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1
Wang, Xufeng Materials Science & Engineering Faculty of Science UNSW. "Application of single-part adhesives as healing agent in self-healing composites." Awarded by:University of New South Wales. Materials Science and Engineering, 2007. http://handle.unsw.edu.au/1959.4/32233.
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The aim of this study was to develop a new single-part healing system for self-healing composites. The self-healing approach to composite repair has been developed in the last two decades and means that a damaged area can be repaired by material already housed within the structure. The background and development of self-healing has been reviewed. The two main self-healing mechanisms are discussed. To date only two part self healing systems have been examined. These require diffusion of the separate constituents to a single location in order to effect cure and restore strength. Single part adhesives do not have this disadvantage and are therefore very attractive. Several candidate single-part adhesive or resin systems were considered and discussed according to the critical requirements of a self-healing system. A series of experiments was undertaken to evaluate the possibility of candidate adhesive systems being effective for self-healing by focusing on the determination of storage stability and bonding efficiency. The results of storage stability testing showed that the stability of cyanoacrylate and polyurethane adhesives was poor. However silane and polystyrene cements showed good storage stability. Very low bonding efficiency was achieved with polystyrene cement but a 22% strength recovery was obtained with the silane 3-[tris(trimethylsiloxy)silyl]-propylamine. Suggestions for further research into single-part healing systems are also given.
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Shaohua, Qi. "Self-Healing Cements with Epoxy and Mercaptan Microcapsules or Polycaprolactone Particles as Healing Agent." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/27395.
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Cementitious materials are the most wildly used construction materials in the world, and the development of self-healing cementitious materials are highly beneficial. The aim of the thesis is to use dual-microcapsules or polycaprolactone as self-healing agent, and to study the self-healing properties and fracture mechanics of the self-healing cement.
Microcapsule based self-healing cement in this work is fabricated by adding 10, 20 and 30 wt.% of dual-microcapsules to the cement. The dual-microcapsule system contains a bisphenol A diglycidyl ether (DGEBA) epoxy resin in one capsule and pentaerythritol tetrakis (i.e. mercaptan) as hardener in the other capsule. Polycaprolactone (PCL) based self-healing cement is prepared by adding 10, 20 and 30 wt.% of PCL powders to the cement. The study of self-healing efficiency and fracture behaviour of the self-healing cement are carried out using the TDCB (tapered double-cantilever beam) fracture tests.
For the microcapsules based self-healing system, microcapsules can be classified by three diameters. The diameters of epoxy microcapsules are 210 μm and 71 μm; the diameters of mercaptan microcapsules are 181 μm and 77 μm. The epoxy TDCB with inserted cement block was adopted in fracture characterization of the virgin cements without and with the healing agent as well as that after healing. The cement block is square or round in shape; the specimens with square shape cement showed inconsistent cracking, and most cracking started from edges rather than the pre-crack. The specimens with round shape cement showed consistent cracking along the pre-crack. 10, 20 and 30 wt.% of large microcapsules were added in the cement. The average healing efficiency of cement specimens is 4.6%, 48.1%, and 25.4%, respectively, for 10%, 20%, and 30% of large microcapsules, increasing with the content of healing agent.
For the PCL based self-healing system, the average diameter of PCL powder is 367 μm, and the melting point is 63°C defined by DSC. Rheology of PCL powders shows shear thinning behavior due to a decrease of viscosity under shear rate. The specimens healed at 110°C show better healing efficiency than those healed at 90°C; all of them reach 100% of healing efficiency except the specimens with 10% of PCL healed at 90°C. The maximum healing efficiency reaches 244% for the specimens embedded with 30% of PCL and healed at 110°C.
In conclusion, the healing efficiency increases with the content of epoxy microcapsules or PCL particles, because more coverage of the epoxy or PCL on the cracked surfaces. PCL-based cement at a high healing temperature shows better healing efficiency owing to the lower viscosity and better flow of PCL. PCL-based self-healing system shows better healing efficiency than epoxy microcapsules because of some microcapsules ruptured during the mixing process with the cement, losing its function.
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Bou, ghosn Steve Martin. "Simulating Multi-Agent Decision Making for a Self Healing Smart Grid." Diss., North Dakota State University, 2013. https://hdl.handle.net/10365/27200.
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Dynamic real-time power systems like the national power grid operate in continuously changing environments such as adverse weather conditions, power line malfunctions, device failures, etc. These disruptions can lead to different fault conditions in the power system, ranging from a local outage to a cascading failure of global proportions. It is vital to be able to guarantee that all consumers with critical loads won?t be seriously affected when these outages occur, and to also be able to detect potential faults early on, to prevent them from spreading and creating a generalized failure. In order to achieve this, the power grid must be able to perform intelligent behavior to adapt to ever changing conditions and also to self-heal itself in the event that a fault condition occurs.
The Smart Grid must continuously monitor its own status and if an abnormal state is detected, it must automatically perform corrective actions to restore the grid to a healthy state. Due to the large scale and complexity of the Smart Grid, anticipating all possible scenarios that lead to performance lapses is difficult [2]. There is a high degree of uncertainty in accurately estimating the impact of disruptions on the reliability, availability and efficiency of the power delivery system. The use of simulation models can promote trust in Smart Grid solutions in safe and cost effective ways.
In this work, we first present an innovative framework that can be used as a design basis when implementing agent based simulations of the smart grid. The framework is based on two primary concepts. First, the electrical grid system is separated into semi-autonomous units or micro-grids, each with their own set of hierarchically organized agents. Second, models for automating decision-making in the grid during crisis situations are independently supported, allowing simulations that can test how agents respond to the various scenarios that can occur in the smart grid using different decision models. Advantages of this framework are scalability, modularity, coordinated local and global decision making, and the ability to easily implement and test a large variety of decision models.
4
Uzukwu, Elochukwu Eugene. "Healing Memories: The church as agent of Reconeiliation In the Service of the Kingdom." Bulletin of Ecumenical Theology, 1997. http://digital.library.duq.edu/u?/bet,676.
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Imperiale, Vita. "Design and formulation of a bespoke self-healing agent for repair of multifunctional fibre reinforced polymers." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582821.
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The aim of this investigation was to design a bespoke self-healing agent (SHA) formulation in order to achieve a fully autonomous healing functionality, which provides effective and timely in-situ repair of FRP composite laminates. The preliminary phase of the design process consisted of the identification of the SHA requirements, the choice of epoxy resins as the most suitable chemistry and, finally, the selection of the best candidate species, amongst the many commercially available. Numerous formulations were then generated by the combination of the above components. Therefore, an initial downselection process, with chemical and physical properties characterisation was necessary to consider only a limited number of formulations for mechanical properties characterization. A Mode I fracture toughness test was considered as a means of final selection, the adhesive function being one of the most important functional requirements. Finally, the recovery of residual compressive strength after impact (CAI) was used as a validation method, which was able to demonstrate and quantify the self-healing recovery within a FRP laminate. A very low viscosity epoxy based formulation with a slightly higher fracture toughness than the host composite matrix and good degree of reactivity was selected as having the best overall performance. Adhesion, as a function of time and temperature, was further assessed in this formulation. It was demonstrated that a certain degree of load bearing ability can be achieved after limited reaction extent with full recovery of load bearing ability after 6 hours at 25°C. An ageing assessment of SHA demonstrated that after seven days exposure to 60°C the formulation possessed excellent adhesive properties. The novel integration of a two-part SHA, with the components segregated within different hollow glass fibres for a fully autonomous process, required the development of a suitable manufacturing and design of the FRP laminate. The damaged and self-healed samples achieved 93% of the strength relative to the initial pristine configuration. Besides an increase in the failure load, self-healing generated a significant change in the stress-strain characteristics, which restored a degree of linearity up to failure, and a reduction in the differential strains (and hence increased buckling resistance). The bleeding of the SHA from storage in the HGF to effect healing can be implied from ultrasonic C-scan analysis, where images of self- healing samples possessed fragmented and less defined delamination contours compared to the image of damaged samples without SHA within hollow glass fibres. This investigation has demonstrated that a fully autonomous recovery of a significant proportion of compressive strength in a CFRP is possible via self-healing. For the first time it has been demonstrated that a bespoke multi-component SHA is able to bleed from embedded HGF, self-mix and react to allow recovery of up to 93% of compressive strength, notwithstanding the presence of remaining damage within the CFRP laminate
6
Suurhasko, Kai. "”Jag har alltid trott att det finns något men inte hittat något” : Att leva alternativa diskurser." Thesis, Linköping University, Department of Social Anthropology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-9317.
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Uppsatsen handlar om tre informanter som intervjuats angående sin syn på alternativa behandlingar och alternativa diskurser i kontrast till dominerande diskurser inom medicin och samhälle. Viktiga avsnitt rör till exempel sådant som vad är healing, hur kan en behandling gå till, grundläggande synsätt i alternativa diskurser och hur man ser på sjukdom.
This paper is about three informants. I have interviewed them in the context of their views about alternative discourses in contrast to the dominating discourses in medicine and society. Important parts in the paper touch healing, how treatment is carried out, basic thinking in alternative discourses and how disease is perceived?
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Menke, Nathan. "A COMPUTATIONAL BIOLOGY APPROACH TO THE ANALYSIS OF COMPLEX PHYSIOLOGY: COAGULATION, FIBRINOLYSIS, AND WOUND HEALING." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2093.
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The birth of complexity research derives from the logical progression of advancement in the scientific field afforded by reductionist theory. We present in silico models of two complex physiological processes, wound healing and coagulation/fibrinolysis based on two common tools in the study of complex physiology: ordinary differential equations (ODE) and Agent Based Modeling (ABM). The strengths of these two approaches are well-suited in the analysis of clinical paradigms such as wound healing and coagulation. The complex interactions that characterize acute wound healing have stymied the development of effective therapeutic modalities. The use of computational models holds the promise to improve our basic approach to understanding the process. We have modified an existing ordinary differential equation model by 1) evolving from a systemic model to a local model, 2) the incorporation of fibroblast activity, and3) including the effects of tissue oxygenation. Possible therapeutic targets, such as fibroblast death rate and rate of fibroblast recruitment have been identified by computational analysis. This model is a step toward constructing an integrative systems biology model of human wound healing. The coagulation and fibrinolytic systems are complex, inter-connected biological systems with major physiological roles. We present an Agent Based Modeling and Simulation (ABMS) approach to these complex interactions. This ABMS method successfully reproduces the initiation, propagation, and termination of blood clot formation and its lysis in vitro due to the activation of either the intrinsic or extrinsic pathways. Furthermore, the ABMS was able to simulate the pharmacological effects of two clinically used anticoagulants, warfarin and heparin, as well as the physiological effects of enzyme deficiency/dysfunction, i.e., hemophilia and antithrombin III-heparin binding impairment, on the coagulation system. The results of the model compare favorably with in vitro experimental data under both physiologic and pathophysiologic conditions. Our computational systems biology approach integrates reductionist experimental data into a cohesive model that allows rapid evaluation of the effects of multiple variables. Our ODE and AMBS models offer the ability to generate non-linear responses based on known relationships among variables and in silico modeling of mechanistic biological rules on computer software, respectively. Simulations of normal and disease states as well as effects of therapeutic intervention demonstrate the potential uses of computer simulation. Specifically, models may be applied to hypothesis generation and biological advances, discovery of new diagnostic and therapeutic options, platforms to test novel therapies, and opportunities to predict adverse events during drug development. The ultimate aim of such models is creation of bedside simulators that allow personalized, individual medicine; however, a myriad of opportunities for scientific advancement are opened through in silico experimentation.
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Ratti, James A. "INVESTIGATING SMOKE EXPOSURE AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) WITH A CALIBRATED AGENT BASED MODEL (ABM) OF IN VITRO FIBROBLAST WOUND HEALING." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5441.
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COPD is characterized by tissue inflammation and impaired remodeling that suggests fibroblast maintenance of structural homeostasis is dysregulated. Thus, we performed in vitro wound healing experiments on normal and diseased human lung fibroblasts and developed an ABM of fibroblasts closing a scratched monolayer using NetLogo to evaluate differences due to COPD or cigarette smoke condensate exposure. This ABM consists of a rule-set governing the healing response, accounting for cell migration, proliferation, death, activation and senescence rates; along with the effects of heterogeneous activation, phenotypic changes, serum deprivation and exposure to cigarette smoke condensate or bFGF. Simulations were performed to calibrate parameter-sets for each cell type using in vitro data of scratch-induced migration, viability, senescence-associated beta-galactosidase and alpha-smooth muscle actin expression. Parameter sensitivities around each calibrated parameter-set were analyzed. This model represents the prototype of a tool designed to explore fibroblast functions in the pathogenesis of COPD and evaluate potential therapies.
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Abdeldayem, Ali I. A. "The effect of synthetic cannabinoids on wound healing of chondrocytes monolayers and pseudo 3D cartilage tissue. Effect of different concentrations of synthetic cannabinoids WIN55, 212-2, URB602 and HU-308 with and without their antagonists on wound healing of chondrocyte monolayers and pseudo 3D cartilage tissue." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6316.
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Studies have been conducted to highlight the anti-inflammatory and immunosuppressive
properties of cannabinoids and also their potentials for cartilage repair and regeneration.
Various wound healing techniques can be used to investigate the mechanisms of
chondrocyte repair in monolayers or three dimensional tissue constructs. The effect of
different concentrations of the synthetic cannabinoids WIN55, 212-2 (WIN-2), URB602
and HU-308 with and without their antagonists on the wound healing of chondrocyte
monolayers was investigated using a simple scratch assay model. The three
cannabinoids were found to increase wound healing of chondrocyte monolayers, but at
different rates. WIN55, 212-2 at a concentration of 1μM had the highest effect of
increasing both migration and proliferation of chondrocytes cultured in a chondrogenic
media, which increased the rate of wound closure. It was also found that treating the
cells with 2μM of any of the cannabinoids lead to a decrease in cell proliferation and the
rate of wound closure. These findings were further investigated, by studying the effect
of WIN-2 on nitric oxide (NO) and matrix metalloproteinase-2 (MMP-2) expressed by
wounded chondrocyte monolayers. Moreover, expression of collagen type-I, collagen
type-II, fibronectin and S100 proteins were detected using immunofluorescence and
verified quantitatively using ELISA based techniques, following treatment with 1μM
and 2μM of WIN-2, for both 2D monolayers and 3D sheets. Treating chondrocytes with
1μM of WIN-2 significantly increased collagen type-II, fibronectin and S100, and
significantly reduced collagen type-I compared to control groups in monolayers and
chondrocyte cell sheets. On the other hand, both concentrations of WIN-2 significantly
reduced the expression of the inflammation markers NO, and MMP-2, in a dose
dependent manner. These findings highlight the potential use of the synthetic
cannabinoid for improving the rate of wound closure as well as acting as an antiinflammatory
agent, which could be used to enhance tissue engineering protocols aimed
at cartilage repair.Egyptian Government
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Abdeldayem, Ali Ibrahim Al. "The effect of synthetic cannabinoids on wound healing of chondrocyte monolayers and pseudo 3D cartilage tissue : effect of different concentrations of synthetic cannabinoids WIN55, 212-2, URB602 and HU-308 with and without their antagonists on wound healing of chondrocyte monolayers and pseudo 3D cartilage tissue." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6316.
Full textAbstract:
Studies have been conducted to highlight the anti-inflammatory and immunosuppressive properties of cannabinoids and also their potentials for cartilage repair and regeneration. Various wound healing techniques can be used to investigate the mechanisms of chondrocyte repair in monolayers or three dimensional tissue constructs. The effect of different concentrations of the synthetic cannabinoids WIN55, 212-2 (WIN-2), URB602 and HU-308 with and without their antagonists on the wound healing of chondrocyte monolayers was investigated using a simple scratch assay model. The three cannabinoids were found to increase wound healing of chondrocyte monolayers, but at different rates. WIN55, 212-2 at a concentration of 1μM had the highest effect of increasing both migration and proliferation of chondrocytes cultured in a chondrogenic media, which increased the rate of wound closure. It was also found that treating the cells with 2μM of any of the cannabinoids lead to a decrease in cell proliferation and the rate of wound closure. These findings were further investigated, by studying the effect of WIN-2 on nitric oxide (NO) and matrix metalloproteinase-2 (MMP-2) expressed by wounded chondrocyte monolayers. Moreover, expression of collagen type-I, collagen type-II, fibronectin and S100 proteins were detected using immunofluorescence and verified quantitatively using ELISA based techniques, following treatment with 1μM and 2μM of WIN-2, for both 2D monolayers and 3D sheets. Treating chondrocytes with 1μM of WIN-2 significantly increased collagen type-II, fibronectin and S100, and significantly reduced collagen type-I compared to control groups in monolayers and chondrocyte cell sheets. On the other hand, both concentrations of WIN-2 significantly reduced the expression of the inflammation markers NO, and MMP-2, in a dose dependent manner. These findings highlight the potential use of the synthetic cannabinoid for improving the rate of wound closure as well as acting as an antiinflammatory agent, which could be used to enhance tissue engineering protocols aimed at cartilage repair.
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SOUZA, NETO JÚNIOR José de Castro. "Avaliação de feridas cutâneas em ratos tratadas com creme à base de extrato de ameixa-do-mato (Ximenia americana) a 10%." Universidade Federal Rural de Pernambuco, 2016. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/4460.
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This study aimed to evaluate the healing activity, herbal profile and the acute toxicity of American Ximenia. 60 Wistar rats (Rattus norvegicus albinus), males, with an average body weight 270 g and 60 days old. the animals were divided into 03 groups of 20 animals each (GTX - animals with wounds treated with cream containing Ximenia americana at 10%; GP - animals with wounds treated with cream base;. GC- animals with untreated wounds) subdivided into 4 groups of 5 animals corresponding to the healing time 4, 7, 14 and 21 days in each animal were two surgical wounds (right and left antimere) leaving exposed the adjacent fascia. the wounds were measured in the degree of contraction and evaluated morphological and histomorphometric on the number of fibroblasts, blood vessels, collagen fibers and mast cells. For the acute study, 5 mice were selected Swiss albino, male, average body weight of 45 g and 60 days of age. Doses of 300 mg / kg 2000 mg / kg ethanol extract of the plant intraperitoneally. Acute toxicity was evaluated from the effects on the central and peripheral nervous system with estimated LD50. The phytochemical profile analysis was done by Thin Layer Chromatography. The degree of contraction of the wounds was significantly higher in the treated group when compared with standard and control groups (p <0.05). The GTX group had higher concentrations of fibroblasts, blood vessels in the 4th and 7th postoperative day and collagen fibers (all time) and reducing the number of mast cells when compared with the other groups (p <0.05). The hydroalcoholic extract showed no lethality in toxicity testing. The phytochemical study revealed the presence of tannins, flavonoids and terpenoids. The American Ximenia cream 10% did not increase the number of mast cells during wound healing, but proved to be efficient in the contraction of skin wounds in mice, angiogenesis and fibroplasia, promoting healing. These findings may be related to the presence of chemical constituents, tannins and flavonoids, which makes this plant a potential source of material for the production of herbal medicines.
O presente estudo objetivou avaliar a atividade cicatrizante, o perfil fitoterápico e a toxicidade aguda da Ximenia americana. Foram utilizados 60 ratos Wistar (Rattus norvergicus albinus), machos, com peso corporal médio de 270 g e 60 dias de idade. Foram distribuídos em 03 grupos de 20 animais cada (GTX – animais com feridas tratadas com creme contendo Ximenia americana a 10%; GP –animais com feridas tratadas com creme base; GC – animais com feridas não tratadas) subdivididos em 4 grupos de 5 animais, correspondente aos tempos de pós-operatório (PO): 4, 7, 14 e 21 dias. Em cada animal foram realizadas duas feridas cirúrgicas (antímero direito e esquerdo) deixando exposta a fáscia muscular adjacente. As feridas foram mensuradas quanto ao grau de contração e avaliadas morfológica e histomorfometricamente quanto ao número de fibroblatos, neovasculação, fibras colágenas e mastócitos. Para o estudo de toxicidade aguda, foram selecionados 5 camundongos Swiss albinos, machos, peso corporal médio de 45 g e 60 dias de idade. Foram administradas doses de 300 mg/Kg, 2000 mg/kg do extrato etanólico da planta, por via intraperitoneal. A toxicidade aguda foi avaliada a partir dos efeitos sobre o sistema nervoso central e periférico com estimativa da DL50. A análise do perfil fitoquímico foi realizado por Cromatografia em Camada Delgada. O grau de contração das feridas foi significativamente maior no grupo tratado, quando comparado com os grupos padrão e controle (p<0,05). O grupo GTX apresentou maiores concentrações de fibroblastos, vasos sanguíneos no 4o e 7o dia de PO, fibras colágenas (todos os tempos) e redução do número de mastócitos quando comparado com os demais grupos (p<0,05). O extrato hidroalcoólico não apresentou letalidade no teste de toxicidade. O estudo fitoquímico revelou a presença de taninos, flavanoides e terpenóides. O creme de Ximenia americana a 10% mostrou ser eficiente na contração de feridas cutâneas em ratos, na angiogênese e fibroplasia, favorecendo a cicatrização. Estes achados podem estar relacionados a presença dos constituintes químicos, taninos e flavanoides, o que faz desta planta uma potencial fonte de matéria para produção de fitoterápicos.
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Al-Mansoori, Tariq Hussein Abees. "Encapsulated healing agents for asphalt self-healing." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/51801/.
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Service life of asphalt roads could be extended by enhancing the natural self-healing ability of asphalt mixtures with encapsulated rejuvenators. When crack damage appears, the capsules release healing agents, which dissolve bitumen to flow into cracks. In this research, a new type of capsules was developed. These capsules contain sunflower oil as a rejuvenating agent. The size, morphology, mechanical strength and thermal stability of these capsules were investigated. The composition of the capsules, which nominally divides these capsules into different types based on their oil content, epoxy-cement shell and polymer amount, and its effect on capsule characteristics were also studied. In addition, the effect of the capsules on the chemical composition of bitumen with time of exposure to broken capsules was evaluated by the FTIR test. Results show that the characteristics of the capsules and their effect on chemical composition allow them to be incorporated in asphalt mixtures for further investigations for their effect on asphalt mechanical performance and self-healing. The mechanical performance of aged asphalt mixtures is investigated by using three nominally different types of capsules. Two of these were protected with a hard shell made of epoxy-cement composite; two coats with 1.0 o/w (oil-to-water), three coats with 1.0 o/w and without the hard shell with 0.5 o/w. The optimum amount of capsules used in all mixtures was 0.5% of total mass of asphalt mixture. Tests started by investigating the effect of mixing and compaction processes on these capsules. Results show that the hard shell (epoxy-cement) was not necessary for the capsules to survive mixing and compaction processes. Capsules deformed and broke with cyclic loading, releasing oil that diffused in the bitumen in less than 24h. Healing of cracks in aged asphalt mixtures led to an increase of stiffness under cyclic loading. However, asphalt specimens with capsules had lower deformation resistance. Computer tomography scanning of specimens showed large reductions in cracks around the capsules, after resting 4 days (96h) at 20oC. The mechanical properties of asphalt mixture containing capsules have been evaluated. Including water sensitivity, particle loss, stiffness and permanent deformation. One type of capsule (0.1 o/w) with three different capsule contents by mass of asphalt mixture were used, 0.1%, 0.25% and 0.5% with oil-to-bitumen ratio 1.1, 2.8 and 5.5, respectively. Capsules were strongly bonded to the asphalt mixture and results showed improved or at least similar mechanical properties to that of asphalt mixtures without capsules. This shows that capsules for asphalt self-healing can be safely used in the road, without affecting its quality. Asphalt containing capsules had slightly lower stiffness (no rest period), which can be easily solved by reducing the size of the capsules in the future. Furthermore, a new method for testing asphalt self-healing by the action of capsules was designed and tested. This method was based on a 3-point bending test (3PB) to beak samples and measure their flexural strength. The test was implemented by comparing the strength recovery of the broken beams after healing to their original flexural strength. The test was first applied to asphalt mastic beams, which are asphalt mixtures with higher bitumen content and fine aggregate and filler. Five different types of capsules used, based on their o/w ratios. These were 0.05, 0.1, 0.2, 0.5 and 1.0 o/w ratios with different amounts depending on their oil content so that they can provide a 7.2% of rejuvenator (sunflower oil) to the asphalt mastic beams. The effect of capsule content on self-healing was investigated by the 3PB on samples containing all those five capsule types (different contents) at one healing temperature, namely 20oC and different healing times. Effect of temperature on healing was investigated as well by 3PB test applied to mastic beams containing one type of capsules with 0.5 o/w ratio at four different temperatures, namely 5oC, 10oC, 15oC and 20oC. The main results showed that the capsules can break inside the asphalt mastic releasing the encapsulated oil to bitumen. Healing levels in the asphalt mastic samples with capsules were greater than samples without capsules, and the healing level of asphalt samples with, and without, capsules increased with the healing time. Additionally, the healing level given by the capsules inside the cracked asphalt mastic depended on the oil/water content of the capsule and on the temperature at which the healing process occurs. Finally, a correlation factor was developed between the healing level of asphalt mastic with and without capsules, independent of the temperature and time evaluated. Self-healing of real asphalt mixture was also investigated by same method of 3PB at different healing times and different temperatures. One type of capsules, namely 0.1 o/w with three different capsule contents, 0.10%, 0.25% and 0.50% by total weight of the mixture, were mixed with the asphalt. Eight different healing temperatures were used in this test, namely -5oC, 5oC, 10oC, 15oC, 20oC, 30oC, 40oC and 50oC. It was proven that the capsules can resist the mixing and compaction processes and break inside the asphalt mixture as a result of applying external mechanical loads, releasing the encapsulated oil. The capsules content in asphalt mixture has a significant influence on the healing level, where a higher capsule content led to higher healing levels. It was found that cracked asphalt mixture with capsules recovered 52.9% of initial strength at 20oC versus 14.0% of asphalt mixture without capsules. Likewise, asphalt with, and without, capsules presents an increase of the healing level when the temperature increases. Finally, it was proved that healing temperature over 40oC has significant influence on the healing levels of the asphalt beams.
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Rae, Steven Inglis. "Novel self-healing systems : expanding and inhibited healing agents." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702144.
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The concept of self-healing materials has emerged from the reticence that exists in composite design, especially in aerospace structures. This concern emanates from composite materials' poor interlaminar properties and therefore tendency to perform badly when subject to impact events, typically manifesting as matrix cracking, delamination, and fibre debonding. With even microscopic damage having the potential to grow under fatigue loading until the structure's mechanical properties are diminished, composite structures are manufactured with high built in safety factors and structural redundancy to counteract inevitable defect creation. By developing self-healing materials, these defects can be addressed before (or after) they are allowed to grow, thus reducing the requirement for structural redundancy and capitalise on the mass savings that result. The chemistry behind healing mechanisms, and. methods of incorporating healing functionality itself, has been intensely researched by many groups in recent years. Whilst impressive results have been observed, and respecting the advancements that have been achieved, there still exist challenges which need to be addressed to allow for effective and fully autonomous self-healing systems. Many studies report thermal activation of polymerisation reactions, pre-mixing of healing agents, manual closing of crack planes to increase the relative volume of healing agent, or artificial opening of crack planes to increase infiltration and alleviate tensile stresses on the healing agent. Fundamentally however, achieving high healing efficiencies relies on delivering an adequate volume of healing agent(s) in a stoichiometric ratio and achieve effective mixing, or relies on exposing embedded catalyst to initiate and sustain polymerisation. We aim to address some of these challenges and reduce the dependency on external stimulus to increase healing efficiency in an autonomous manner through two different approaches. Firstly, the problems associated with incorporation of catalyst into the matrix, achieving stoichiometric ratios, and effective mixing, can be addressed using a single part healing chemistry that requires no additional stimulus or catalyst after release to polymerise. We have therefore investigated a potential route to 'inhibited healing' whereby a resin is actively prevented from undergoing polymerisation until released from the delivery vessel, whereupon polymerisation occurs rapidly and autonomously., Secondly, problems associated with mixing, reducing fibre disruption from vascule incorporation, delivering adequate volume from smaller reserves, achieving high proportions of infiltration, or to address larger damage voids and bridge wider separations, can be achieved by creation of volume in the healing agent , itself. We have investigated different chemical systems to produce a structural polymer with a volume greater than the sum of its constituent parts, explored methods of tailoring its chemical and structural properties, and assessed its ability to repair not only the relatively small volumes associated with damage within laminate structures, but also the larger damage volumes associated with impacted sandwich structures.
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Cope, Tim S. "Self-healing composites via metal triflate catalytic curing agents." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682235.
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This research focuses on the development and implementation of novel self-healing chemistries for fibre reinforced polymer (FRP) composite materials that are cost effective, compatible with the host epoxy-based matrix material, stable to environmental conditions (i.e. air and moisture) and achieve high healing efficiencies after the initial fracture event. The initial 'proof of concept' study involved identifying a suitable catalytic curing agent that was capable of initiating the ring-opening polymerisation (ROP) of epoxides, to restore the fracture toughness of the host epoxy matrix after a fracture event had occurred. The solid-state Lewis acid catalytic curing agent, scandium(III) triflate (Sc(OTf)3), was selected as the healing agent and the healing efficiency was quantitatively evaluated using a tapered double cantilever beam (TDCB) test specimen geometry. To provide an efficient delivery method for the epoxide constituent, microcapsules containing diglycidyl ether bisphenol A (DGEBA) epoxy resin and a non-toxic solvent, ethyl phenylacetate (EPA), were synthesised via an in situ urea-formaldehyde microencapsulation procedure. Autonomous (AUTO) test specimens containing embedded Sc(OTf)3 particles and DGEBAEPA microcapsules, resulted in >80% recovery of the host matrix fracture toughness value. Heating at moderately raised temperatures accelerated the ring-opening polymerisation (ROP) of the epoxy resin. Due to the inherent volume limitations of a microcapsule-based system, a bio-inspired microvascular geometry for self-healing agent delivery was implemented into glass and carbon FRP composites, to facilitate the repair of large internal damage volumes. Thermal cure analysis and mechanical characterisation of the metal triflate-initiated self-healing polymers were also investigated to optimise cure conditions at low temperature and to investigate the influence of reagent loadings on the mechanical properties. Suitable self-healing agents were externally injected into a double cantilever beam (DCB) test specimen geometry via 0.5 mm microvascule channels located on the composite laminate mid-plane, where the healing agent was left to autonomously wet out the exposed fractured crack planes. Initially, pre-mixed and non-mixed self-healing agents were evaluated in glass FRP (GFRP) DCB test specimens and left to cure at moderately raised temperatures, to provide healing efficiency values of >99% for fracture toughness and load, at the point of crack initiation. To assess the transfer of this technology to carbon FRP composites, DCB test specimens were manufactured using out of autoclave (OOA) techniques that contained embedded Sc(OTf)3 catalyst on the composite laminate mid-plane. The catalyst was subsequently exposed during testing via the propagating crack. Fractured specimens were injected with an epoxy-EPA solution to initiate healing and provide a 60% restoration of the initial fracture toughness value after 24 hours at 80 QC. This research, therefore, demonstrates the tailorability of the underpinning chemistry of this self-healing system, across a variety of delivery systems, in epoxy-based polymer composite materials.
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Everitt, Daniel Thomas. "Self-healing agents for application in fibre-reinforced polymers." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707746.
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Roy, Rahul. "Bacteria - based self - healing mortar with bio - plastic healing agents : Comparative analysis on quantification and characterization of self-healing by various experimental techniques." Thesis, KTH, Betongbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289227.
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Crack formation in concrete structures due to various load and non-load factors leading to degradation of service life is very common. Repair and maintenance operations are, therefore, necessary to prevent cracks propagating and reducing the service life of the structures. Accessibility to affected areas can, however, be difficult and the reconstruction and maintenance of concrete buildings are expensive in labor and capital. Autonomous healing by encapsulated bacteria-based self-healing agents is a possible solution. In this study, a novel bacteria-based healing agent was investigated in order to test the self-healing efficiency of the specimens in comparison to the commonly used healing agents made of lactic acid derivatives. (PLA). The novel integrated healing agent is a non-toxic, biodegradable dissolved inorganic carbon substrate derived from wastewater that has been used as an encapsulation material for spores of cohnii bacteria in the Bacillus gene family and for nutrients made up of yeast extract. This dissolved inorganic carbon substrate is a bioplastic made by the bacteria in wastewater known as alkanoate derivatives (AKD). To assess the effect of these healing agents on the mortar characteristics, quantification and characterization of the self-healing were conducted. The quantification of the self-healing efficiency was performed by various experimental techniques such as light microscopy, water permeability, chloride ion permeability, and thermogravimetric analysis whereas the material characterization was investigated by x-ray diffraction and environmental scanning electron microscope. Moreover, a statistical analysis was performed to study the correlation of self-healing efficiency between various experimental techniques. The incorporated dosages of healing agents adopted were 2.6% and 5% by weight of cement. Complete immersion in water was considered to be the condition of treatment of the specimen for healing at two separate periods of 28 and 56 days. The crack widths investigated were in the range of 0.04 to 0.8 mm. The quantification and characterization tests indicated that bacterial containing mortar series especially PLA and AKD at 5% dosage displayed a higher self-healing performance and an indication of precipitated calcium carbonate in the crack mouth. However, the results from the chloride migration test didn’t show any influence by the self-healing healing agents. Furthermore, the statistical analysis identified a major impact of the internal crack geometry on the difference in self-healing ratios, also in the cases where effective crack width is equal.Sprickbildning i betongkonstruktioner p.g.a. olika laster och lastoberoende faktorer som leder till förkortning av livslängden är mycket vanligt förekommande. Reparation och underhåll är därför nödvändiga för att förhindra att sprickorna propagerar och reduceras konstruktionernas livslängd. Möjligheterna att komma åt de skadade partierna kan dock vara svåra och reparationerna är vanligen både arbetsintensiva och kostsamma. Självläkning med ingjutna bakteriebaserade, självläkande tillsatser är en möjlig lösning på problemet. I denna studie undersöktes en ny bakteriebaserat självläkande tillsats för att prova den självläkande förmågan i jämförelse med vanligt förekommande självläkande tillsatser av mjölksyrederivat (PLA). Den nya integrerade självläkande tillsatsen är en giftfri, biologiskt nedbrytningsbar, oorganisk kolsubstratslösning utvunnen ur avloppsvatten, en tillsats som har använts som ett inkapslingsmaterial för sporer från cohnii-bakterier från bacillussläktet och från näringsämnen framställda ur jästextrakt. Denna kolsubstratslösning är en bioplast framställd ur avloppsvatten och känd som alkanoatderivat (AKD). För att bestämma effekten av dessa självläkande tillsatser på cement bruks egenskaper genomfördes kvantifiering och karakterisering av självläkningen. Kvantifieringen av självläkningens effektivitet utfördes genom olika experimentella metoder såsom ljusmikroskopi, vattengenomsläpplighet, kloridjonstransport och termogravimetriska analyser medan materialkarakteriseringen utfördes med röntgendiffraktion och svepelektronmikroskop (ESEM). Vidare genomfördes en statistisk analys för att undersöka korrelationen mellan olika experimentella metoder. De doser av självläkande tillsatser som användes var 2,6 och 5 % av cementvikten. Fullständig nedsänkning i vatten ansågs vara den lämpligaste lagringen för självläkning under två olika tidsperioder på 28 respektive 56 dygn. De sprickbredder som studerades låg i intervallet 0.04 till 0.8 mm. Försöken kring kvantifiering och karakterisering indikerade att bruken innehållande bakterier, i synnerhet 5 % PLA och AKD, utvecklade en högre form av självläkande beteende och en förekomst av kalciumkarbonat i sprickspetsen. Resultaten från försöken kring kloridtransport visade emellertid inga tecken på någon effekt från de självläkande tillsatserna. Vidare identifierades i den statistiska analysen att inre sprickbildning har stor betydelse för självläkningseffekten även i fall där den effektiva sprickbredden är lika stor.
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Muzio, Rubens Ramiro. "The healing function of Christian worship a clinical and theological analysis of praise and adoration as healing agents /." Theological Research Exchange Network (TREN), 1991. http://www.tren.com.
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Matheson, Mhairi. "The investigation and development of IGD peptidomimetics as wound healing agents." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6810/.
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An ever increasing incidence of diabetes has resulted in an epidemic of chronic wounds. Few therapies effectively promote wound healing, and thus, health care budgets are faced with an unsustainable burden and patients with poor quality of life. Recently, the isoleucine-glycine-aspartic acid (IGD) tripeptide motif of Migration Stimulating Factor (MSF) has been found to be responsible for the wound healing properties of this protein. Modelling studies of the IGD motif of MSF have lead to the design and synthesis of a benzodiazepinone core, which displays wound healing properties in vitro and in vivo. This thesis discusses the optimisation of the synthetic route to this exciting IGD peptidomimetic and investigations into the activity and the method of action of this molecule through scratch assays and qRT-PCR studies. Analogues of this benzodiazepinone with varying synthetic handles have been developed and used to tag the active bicyclic core with desired technologies. In one such example, BODIPY tagging and confocal microscopy allowed the investigation of fibroblast uptake of the BODIPY IGD peptidomimetic. An IGD peptidomimetic with a triethylene glycol synthetic handle has been developed for increased hydrophilicity and is envisioned to be used in the development of a therapeutic hydrogel.
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Osim, Wilton [Verfasser]. "Surface modification of nanofillers and encapsulation of healing agents for ROMP- and “click”-based self-healing polymer nanocomposites / Wilton Osim." Halle, 2018. http://d-nb.info/1177798581/34.
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McIver, Victoria Clare. "Studies on the effect of various topical agents on second intention wound healing of the equine distal limb." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/24899.
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Traumatic wounds of the distal limb are common in horses. These wounds are often left to heal by second intention because of substantial tissue avulsion and contamination. In the horse second intention healing is often problematic and wounds are susceptible to the production of excessive granulation tissue, which inhibits the progression of healing.
There have been many products recommended to enhance second intention wound healing in horses, however no product has proved to be a treatment panacea. Marijuana (Cannabis sativa) contains more than 60 biologically active chemical agents that have been shown to have potent antibacterial and anti-inflammatory activity as well as the ability to improve elements of healing in a rat skin wound healing model. The current study aimed to investigate the effects of one resin, cannabadiol, on second intention wound healing in horses. The first part of our study was to determine if daily topical application of cannabidiol, in combination with a carrier of manuka honey, would improve wound healing variables in an equine model of second intention wound healing.
Several studies have shown manuka honey enhances second intention would healing in horses in equine wound healing models. As the unique manuka factor (UMF) increases so does the antimicrobial activity of the manuka honey. Most studies have focused on UMF 20 honey in contaminated and uncontaminated equine wound healing models. The second part of our study examined the effect of different UMF honey on second intention wound healing, and compared this to the use of Melaleuca honey. Our hypothesis was that increasing the UMF rating would improve wound healing and that Melaleuca honey would not enhance second intention would healing in the horse.
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Elias, Patrick David. "On the development of the Angiotensin IV ligands, Norleual and NLE¹-Angiotensin IV, as anti-cancer and wound healing agents." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Dissertations/Summer2008/p_elias_052808.pdf.
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Hatch, Dale R. "Training leaders and potential leaders as agents of Christ's healing in the life of local churches." Theological Research Exchange Network (TREN), 2006. http://www.tren.com/search.cfm?p028-0244.
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Mantzaris, Debbie 1974. "Investigation of the mechanisms involved in delayed ulcer healing by nonsteroidal anti-inflammatory drugs (NSAIDs)." Monash University, Dept. of Surgery, 2001. http://arrow.monash.edu.au/hdl/1959.1/8095.
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Khaw, Peng Tee. "The effects of growth factors and antiproliferative agents on ocular fibroblasts and wound healing after glaucoma filtration surgery." Thesis, University College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360508.
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Theunissen, Daniël. "Measurements in wound healing : effects of topical agents on full thickness dermal incised wounds in an animal model." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/8768.
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Bibliography: leaves 55-59.Inert topical agents in the form of creams, lotions and ointments are often applied to wounds to create an environment conducive to wound healing. These agents, although not pharmacologically active on the intact skin, have activity when applied to wounds where the stratum comeum barrier to penetration is absent. From measurements of simple parameters like the rate of re-epitheliasation. it is known that some topical agents enhance wound healing while others retard the healing process. There is data available on the antiseptic and anti-microbial properties of most of the topical agents in use today, but ail the effects of these products on the micro-environment of wounds and their influence on the process of healing is not known. Central to the study of wounds and wound healing is the need for accurate methods to evaluate wounds. Parameters used for measuring outcome should be unambiguous and measurements should be accurate and reproducible. At present, no universally accepted methods of assessing wounds exist. Clinical evaluation is usually subjective and not quantitative, resulting in unacceptable levels of inter- and intra-observer variation. Similarly lacking are clear histological correlates of what we consider good healing characteristics of a wound. As our knowledge increase about the complex process of wound healing, in particular the hormones and peptide growth factors that regulate the process, possibilities arise for therapeutic intervention to enhance or improve clinical outcome. At the same time, the need for objective measurements becomes more urgent, as we need to evaluate and compare treatment options. Previous measurement systems were developed, ranging from visual scoring systems to measurement of biological and chemical wound constituents. Physical characteristics of healing wounds can also be measured by properties such as the tensile strength. The structural and ultra- structural elements of healing wounds remain difficult to measure, although immuno-histochemistry and scanning electron microscopy allows some quantification and simple morphometric measurements. With current advances in computer technology however, rapid, automatic measurements can be made from tissue sections for a variety of practical applications in the pathology laboratory. Image analysis offers dynamic functional imaging, linking multiple data sources to provide composite quantitative systems. Further correlation of detailed histologic examination of wounds to a detailed clinical assessment of the same wounds is important, not only to add credibility to clinical scoring schemes, but also to understand which structural features of the dermis are important for the severity of scarring (and therefore which should be the object of future therapeutic or preventative strategies).
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Cotting, Fernando. "Obtenção de microcápsulas poliméricas contendo um agente formador de filme em seu núcleo para o desenvolvimento de revestimentos autorreparadores." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-15012018-143331/.
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A aplicação de uma ou mais camadas de tinta sobre as superfícies metálicas é a maneira mais comum e eficaz de proteger os substratos metálicos contra o fenômeno da corrosão. No entanto, os sistemas de pintura podem vir a falhar precocemente por diferentes motivos, causando um ataque corrosivo inesperado no metal a ser protegido. Por esta razão, o processo de repintura em estruturas metálicas é realizado frequentemente para garantir a integridade da estrutura pintada e aumentar sua vida útil. Como o processo de repintura gera impactos econômicos e ambientais, sistemas de pintura capazes de sofrerem uma reparação sem a necessidade de uma intervenção humana, precisam ser desenvolvidos. O encapsulamento de agentes de reparação, com propriedades de formação de filme, em microcápsulas poliméricas é uma excelente alternativa para que os sistemas de pintura se autorreparem, aumentando os intervalos de repintura. Após o processo de encapsulamento, as microcápsulas contendo o agente de reparação são incorporadas na preparação da tinta, para que o sistema de pintura seja aplicado sobre a estrutura metálica. Este tipo de aditivação confere ao revestimento a propriedade de autorreparação, pois quando o sistema de pintura é danificado as microcápsulas são rompidas e liberam o agente de reparação no local danificado, protegendo novamente o substrato metálico. Neste trabalho foi desenvolvido um sistema autorreparador monocomponente, através do microencapsulamento de uma resina a base de éster de epóxi, pelo método de polimerização in-situ. Também foi desenvolvido um sistema autorreparador bicomponente, através do microencapsulamento de uma resina a base de epóxi, pelo método de emulsão e polimerização in-situ de ureia-formaldeído-melamina e do seu endurecedor a base de poliamida, pelo método de extração de solvente em paredes de poliestireno. Foi realizado um planejamento estatístico para estudar a emulsão precursora das microcápsulas de poli(ureia-formaldeído-melamina) contendo o sistema monocomponente, onde foram estudados: o tipo e a velocidade de agitação, a presença de cloreto de sódio na formulação, o uso de uma sonda ultrassônica após a etapa de dispersão, a concentração de tensoativo na formulação e o tensoativo utilizado. Como variáveis de resposta foram determinadas: a estabilidade visual das emulsões e o diâmetro das gotículas formadas. A melhor condição de emulsificação determinada foi utilizada para a obtenção das microcápsulas de poli(ureia-formaldeídomelamina) contendo a resina éster de epóxi e das microcápsulas de poli(ureiaformaldeído-melamina) contento a resina epóxi. Entre as condições de emulsificação estudadas, apenas a condição utilizando o tensoativo goma arábica possibilitou a obtenção das microcápsulas de poli(ureia-formaldeído-melamina) na faixa de diâmetro desejada. O método escolhido para o encapsulamento do endurecedor possibilitou a obtenção de microcápsulas de poliestireno, porém com uma baixa capacidade de armazenamento. A liberação dos agentes de reparação encapsulados foi observada pela microscopia óptica e comprovada pela técnica de espectroscopia na região do infravermelho (FTIR) e pela técnica de espectroscopia Raman. Os aditivos autorreparadores desenvolvidos (mono e bicomponente) foram adicionados separadamente em uma tinta epóxi, nas proporções mássicas em base seca de 10 e 15 %. O sistema de pintura foi aplicado em um esquema de três camadas e o aditivo de autorreparação foi incorporado na primeira e/ou segunda camada aplicada. O sistema de pintura contendo o aditivo autorreparador monocomponente apresentou um aspecto visual melhor do que o sistema de pintura contendo o aditivo autorreparador bicomponente, porém o sistema bicomponente forneceu melhores propriedades de aderência, de impermeabilidade, anticorrosivas e de autorreparação à tinta aditivada. As medidas com as técnicas eletroquímicas de espectroscopia de impedância eletroquímica (EIE) e de varredura com eletrodo vibratório (SVET) comprovaram que os dois aditivos desenvolvidos proporcionaram o efeito autorreparador aos sistemas de pintura aditivados, quando estes foram danificados mecanicamente com uma microbroca ou com um estilete. Ensaios acelerados de corrosão em câmara de névoa salina e ensaios de exposição ao intemperismo natural mostraram que os aditivos desenvolvidos promoveram uma proteção adicional ao aço carbono, quando o sistema de pintura foi danificado mecanicamente.The application of one or more coating layers on the metallic surfaces is the most common and effective way to protect metallic substrates against corrosion. Nevertheless, the coating layer may fail early for different reasons, leading to an unexpected corrosive attack on the protected metal. For this reason, the coating repair process is performed to ensure the integrity during the service life of the coated metallic structures. Due to the fact that coating repair process generates economic and environmental impacts; there is a great need for the development of systems capable to repair themselves, without human intervention. The encapsulation of repairing agents, with film forming properties, in polymeric microcapsules is an excellent alternative to the coating self-repair, decreasing the coating repair process frequency. After the encapsulation process, the microcapsules containing the repair agent are incorporated into the paint preparation and the coating system could be applied normally to the metallic surface. This kind of additivation confers to the coating the self-healing property, because when the coating system is damaged the microcapsules suffers a rupture and release the repair agent into the damaged site, protecting the metallic substrate from corrosion. In this work, a mono-component self-healing system was developed, through the microencapsulation of an epoxy ester resin, by the in-situ polymerization method. A bi-component self-healing system was also developed, by the microencapsulation of an epoxy resin, through the emulsion and in-situ polymerization method and by the microencapsulation of a polyamide hardener, by the double emulsion and solvent extraction method. A factorial design was developed to study the precursor emulsion of the poly (urea-formaldehyde-melamine) microcapsules containing the monocomponent system, where the studied factors were: the type and speed of the agitation, the presence of sodium chloride in the formulation, the use of an ultrasonic probe after the emulsification, the surfactant type and concentration. The analyzed response variables were: the visual stability of the emulsions and the mean diameter of the formed droplets. The best obtained emulsification conditions were employed to produce the poly(urea-formaldehyde-melamine) microcapsules containing the epoxy ester resin and poly(urea-formaldehyde-melamine) microcapsules containing the epoxy resin. Among the studied emulsification conditions, only using arabic gum surfactant the poly (urea-formaldehyde-melamine) microcapsules were obtained. The selected method for the hardener encapsulation was efficient to obtain polystyrene microcapsules, but with low loading capacity. The release of the encapsulated repair agents was observed by optical microscopy and confirmed by infrared spectroscopy (FTIR) technique and Raman spectroscopy technique. The developed self-healing additives (mono and bicomponent) were added separately in an epoxy commercial coating, using the dry mass ratios 10% and 15 %. The coating system was applied in a three layer coating system and the self-healing additive was incorporated into the first and/or second layer. The coated samples containing the mono-component additive had a better visual appearance than the bi-component additive system; nevertheless the bi-component system provided better adhesion, impermeability, anti-corrosion and self-healing properties to the doped coating. The electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET) measurements proved that the two developed additives provided self-healing properties to the doped coating systems, when they were mechanically damaged with a micro drill or a blade. Accelerated corrosion tests in the salt spray chamber and natural atmospheric corrosion tests showed that the developed additives provided an additional protection to the carbon steel, when the coating system has been mechanically damaged.
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Carvalho, Luis Eduardo Morato Rebouças de. "Utilização da triancinolona como agente modulador da resposta inflamatória na cirurgia de músculo extra-ocular em coelhos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-25042007-093133/.
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Objetivo: Avaliar a eficiência da Triancinolona Acetonida como agente modulador da resposta inflamatória e cicatricial em coelhos submetidos a cirurgia de músculo extra-ocular. Método: Foi realizado estudo prospectivo, mascarado, em dois estádios. No primeiro estádio, dez coelhos foram submetidos a retrocesso do músculo reto superior em ambos os olhos. Aplicouse, em um deles, 0,15 cc de Triancinolona Acetonida (40mg/cc) nos tecidos circunjacentes ao local de reinserção muscular e, como controle, 0,15cc de solução de cloreto de sódio a 0,9% no local equivalente no olho contra-lateral. Quinze dias após, cinco coelhos foram submetidos a exenteração das órbitas e os restantes dos animais tiveram o mesmo procedimento realizado após trinta dias. O material do sítio de reinserção muscular foi avaliado por meio de análise histopatológica qualitativa e quantitativa (morfometria). No segundo estádio, com incrementação da agressão cirúrgica, dezesseis coelhos foram submetidos aos mesmos procedimentos com exenteração das órbitas após quinze dias, e posterior análise histopatológica dos tecidos. Resultados: Houve efeito inibitório sobre a intensidade da resposta inflamatória nos olhos tratados em comparação com os olhos controle. Conclusão: Nas condições de realização do presente estudo o uso per-operatório da triancinolona acetonida foi efetivo no controle da resposta inflamatória em olhos de coelhos submetidos a cirurgia de músculo extra-ocular.Purpose: To evaluate the efficiency of triamcinolone acetonide (TRI) in limiting the postoperative inflammatory response and scarring following strabismus surgery. Methods: A prospective, two-stage, masked, controlled trial was conducted. In the first stage, the inflammatory response at the extraocular reattachment site was analyzed following superior rectus recession in ten rabbits. One eye had 0,15 cc of triamcinolone acetonide (40mg/cc) applied around the new insertion site and, similarly, 0,15 cc of isotonic saline solution (0,9%) was applied to the fellow eye following the same procedure, thus serving as a control. Fifteen days later, orbital exenteration was performed in five rabbits and the remaining five were exenterated thirty days later. The reattachment site tissues were submitted to qualitative and quantitative histological examinations. In the second stage 16 rabbits were submitted to amplified surgical trauma, after which the aforementioned steps were also carried out. Granuloma total area at the extraocular muscle reattachment sites of control and treated eyes were compared. Results: There was an inhibitory effect of TRI on the inflammatory response of treated eyes as compared to control eyes. Conclusions: TRI was effective in controlling the postoperative inflammatory response in rabbit eyes submitted to traumatic recession of the superior rectus muscle.
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Melo, Lucas Silveira. "Development of a platform for implementing multi-agents systems for application to automatic restoration of electric power distribution systems." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15234.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoIt is common the occurence of permanent faults in power distribution systems. In a typical radial power distribution system when the fault protection system operates, may cause power-off not only in the fault section, but also to all customers downstream the fault.Through disjunction devices normally closed along the feeder, and normaly open on its edges, is possible to isolate the faulty sector and reenergize the healthy ones, reducing the number of customers affected by a fault. Network operators normally do this procedure manually and in addition to demand a considerable ammount of time, is subject to errors on the part of the operator. In order to automate the analisys of the network and provided it of self-healing capacity, various methods have been proposed to solve this matter. Most of these approaches adopts a centralized strategy and do not address the aspect of electric power grid self-healing. In this work is proposed an approach that uses multi-agent systems for self-healing purposes of power distribution systems. Multi-agent are highly suitable for modelling distributed systems in the smart grid domain. For a safe recovery and without violation of operational restrictions the feeder agents perform an evaluation before device agents send any command to the network switches. The proposed multi-agent system is implemented in a agentâs development platform proposed in this work that uses the Python programming language. The platform is called PADE, Python Agent DEvelpment framework. The computer representation of the network, without simplifications, is accomplished by a data encoding based on the theory of graphs and named node-depth representation that serves as a basis for the development of an API of network representation that models each of the required components in the restoration analysis. The device agents communicate with IED that in turn control the switches in the network, by means of IEC 61850 protocols: GOOSE and MMS. To validate the proposed approach, computer simulations are performed using a simplified distribution power grid as a case study and a test platform with relay test case, protection and control IED, managed switch and embedded systems.
à comum a ocorrÃncia de faltas permanentes no sistema de distribuiÃÃo de energia elÃtrica. Por tratar-se de um sistema radial, a atuaÃÃo da proteÃÃo para estas faltas causa a desenergizaÃÃo nÃo sà do setor em falta, mas de todos os consumidores a jusante do setor onde ocorreu a falta. Fazendo uso dos dispositivos de disjunÃÃo normalmente fechados ao longo do alimentador e normalmente abertos nas suas bordas à possÃvel isolar o setor sob falta e re-energizar os setores sÃos, reduzindo o nÃmero de consumidores afetados por um defeito. Este procedimento à normalmente feito pelos operadores da rede, e alÃm de demandar um tempo considerÃvel, està sujeito à erros por parte do operador. No sentido de tornar automÃtica as anÃlises de restauraÃÃo da rede e prover o sistema da capacidade de auto-cura, tÃm sido propostas diversas metodologias para o problema. A maioria destas abordagens adota uma estratÃgia centralizada e nÃo abordam o aspecto de auto-cura da rede elÃtrica. Neste trabalho, à proposta uma abordagem utilizando sistemas multiagentes para recomposiÃÃo de setores de alimentadores de distribuiÃÃo de energia elÃtrica. A tÃcnica de sistemas multiagentes vem se mostrando bastante promissora no desenvolvimento de sistemas distribuÃdos em um contexto de redes elÃtricas inteligentes. Para que a recomposiÃÃo ocorra sem a violaÃÃo das restriÃÃes operacionais e de forma coerente, sÃo feitas anÃlises pelos agentes alimentadores antes que qualquer comando seja enviado para as chaves do sistema por meio de agentes dispositivo. O sistema multiagente proposto à implementado em uma plataforma de desenvolvimento de agentes proposta neste trabalho e que utiliza a linguagem de programaÃÃo Python. A plataforma tem o nome de PADE, Python Agent DEvelpment framework. A representaÃÃo computacional sem simplificaÃÃes da rede à proporcionada por uma codificaÃÃo de dados apoiada na teoria de grafos e denominada RepresentaÃÃo NÃ-Profundidade, que serve de base para o desenvolvimento de uma API de representaÃÃo da rede-elÃtrica que modela cada um dos componentes necessÃrios nas anÃlises de recomposiÃÃo. Ao agente dispositivo à dada a possibilidade de comunicaÃÃo com IED, que controlam as chaves do sistema, por meio dos protocolos da norma IEC 61850: GOOSE e MMS. Para validar a metodologia proposta sÃo realizadas simulaÃÃes computacionais utilizando uma rede de distribuiÃÃo simples como caso base e uma plataforma de testes com: mala de testes de relÃs, IED de proteÃÃo e controle de mercado, switch gerenciÃvel e placas de desenvolvimento de sistemas embarcados.
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Pasternak, Björn. "Towards surgical use of matrix metalloproteinase biology /." Linköping : Department of Clinical and Experimental Medicine, Linköping University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11489.
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Shekede, Blessing Tatenda. "Bactericidal efficacy of wound gauze treated with chitosan nanomaterial hybrids of zinc, silver and copper on common wound bacteria." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2795.
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Thesis (Master of Applied Sciences in Chemistry)--Cape Peninsula University of Technology, 2018.Maintenance of optimum wound chemistry is important to ensure timely healing of a wound. Bacterial infections impair the process of wound healing by producing toxins that alter the chemical environment in and around the wound. The imbalance in the wound chemistry prolongs healing and opens doors to opportunistic infections. Bacteria have developed resistance to conventional bactericides hence, there is need for search of new bactericides that can control bacteria in and around the wound. Therefore, new chemical or biochemical bactericides, which are not resisted by the bacteria, can be explored to control bacterial life around the wound in a bid to maintain optimum wound healing chemistry. Materials such as chitosan, zinc oxide, copper oxide and silver have showed remarkable potential as both bactericidal and wound healing agents. In this work silver, zinc oxide, and copper oxide nanoparticles (NPs) and their chitosan composites (CH-NPs) were synthesized using the chemical reduction method and simple chelation respectively to produce nanoparticles of Ag, ZnO, and CuO as well as composites of CH-ZnO, CH-Ag, CH-CuO, and CH-ZnO-Ag-CuO. Formation of the NPs was confirmed by the exhibition of characteristic peaks in UV-Visible and Fourier Transform Infrared Resonance (FTIR) spectroscopy as well as X-ray diffraction. The nanoparticles (NPs) had optical and electronic band gaps in the range 1 to 5eV indicating their semi-conductive nature. X-ray diffraction (XRD) investigations depicted the crystalline structures of the NPs to be base-centred, face-centred, and hexagonal for Ag, CuO, and ZnO respectively. Transmission electron microscopy (TEM) studies exhibited spherical, hexagonal, and rod-shaped shapes for silver, copper oxide, zinc oxide NPs respectively. Electrochemical investigations of the pure NPs indicated the existence of both the adsorption and the diffusion controlled electron transfer processes at electrode surfaces as well as fast electron transfer rate as depicted by the charge transfer coefficient and standard rate constant parameter values. FTIR spectra of CH-NPs composites depicted new excitation bands absent in spectra of both chitosan and the NPs. The spectra also indicated the deformation and absence of the amine (-NH2) and hydroxyl bands (-OH) within the CH-NPs composites. UV-Visible spectroscopy investigations of the CH-NPs composites exhibited blue-shifts of the λmax with respect to the NPs. The FTIR and UV-Visible spectra confirmed the existence of bonding between the chitosan and the NPs. The optical band gap energies of all the CH-NPs composites fell within the range of 2.0 to 4.5 eV indicating that the CH-NPs fell in the category of the semi-conducting materials after chelating with the chitosan.
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Valente, Rômulo Oliveira de Hollanda. "Avaliação das propriedades tóxicas antiinflamatórias e cicatrizantes do extrato de cravo-da-Índia Syzygium aromaticum (L) Merr. & LM Perry." Universidade Federal da Paraíba, 2006. http://tede.biblioteca.ufpb.br:8080/handle/tede/6633.
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Previous issue date: 2006-12-18Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The aim of this study was to evaluate the acute toxicity of the extract of clove. It was established through the calculation of LD50 by the method of Karber and Behrens (1964) through intraperitoneal and oral routes in mice (Mus musculus). The inflammation and wound-healing process (cicatrization) were evaluated using electric burns in the back of mice albino wistar (Rattus novergicus) treaties with a dermatologic cream with 5% clove extract compared with other two groups: placebo and 5% dexpanthenol (positive-control). The animals were sacrificed in groups in the 2nd, 7th and 14th day of treatment. The results of the study demonstrated the toxicological tests evidenced high toxicity for intraperitoneal route (LD50 = 255 mg/kg) and nontoxic for oral route after complementary dilution of the lipophilic portion of the extract in sunflower oil. The histological evaluation of the surgical specimens demonstrated that the dermatologic cream contributed to the reduction of the infiltrated polymorphonuclear inflammatory cells, and with a great increase of fibroplasias between the 2nd and 7th day of treatment, when compared to placebo and 5%dexpanthenol group. It can be concluded that clove (Syzygium aromaticum L.) has potential for the development of a cutaneous phytotherapeutic agent that can be used as anti-inflammatory and wound-healing drug (cicatrizant) with reduced toxicity.
O objetivo deste estudo foi avaliar a toxicidade aguda do extrato de cravo-da-índia através do cálculo da DL50 pelo método de Karber e Behrens (1964) para as vias de administração intraperitoneal e oral, em camundongos (Mus musculus). A avaliação da inflamação e cicatrização foi realizada em feridas elétricas produzidas com eletrocautério no dorso de ratos albinos wistar (Rattus novergicus), tratados com creme dermatológico contendo extrato de cravo-da-índia a 5% comparativamente a outros dois grupos: placebo e dexpantenol a 5% (controle-positivo). Os animais foram sacrificados em grupos no 2º, 7º e 14º dia de tratamento. Os resultados dos testes toxicológicos evidenciaram elevada toxicidade para via intraperitoneal (DL50 = 255 mg/kg) e atóxica para via oral a partir da diluição complementar da porção lipofílica do extrato com óleo de girassol. A avaliação histológica da pele do dorso dos animais demonstrou que o creme dermatológico contribuiu na redução do infiltrado inflamatório de células polimorfonucleares, e com grande aumento da fibroplasia entre o 2º e o 7º dia de tratamento, quando comparado ao placebo e ao dexpantenol a 5%. Conclui-se que o cravo-da-índia (Syzygium aromaticum L.) apresenta potencial para desenvolvimento de produto fitoterápico antiinflamatório e cicatrizante para utilização humana, com reduzida toxicidade.
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Valente, Fernanda Soldatelli. "Terapia tópica na cicatrização de lesões cutâneas provocadas por congelamento com nitrogênio líquido em ratos Wistar." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/95142.
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A criocirurgia tem sido utilizada no tratamento de diferentes enfermidades de sistemas e órgãos, tanto na medicina humana quanto na medicina veterinária, sendo sua maior indicação o tratamento de dermatopatias. Contudo, efeitos adversos como a cicatrização lenta, cicatrizes extensas, disfunção estética e funcional, foram relatadas após a aplicação da substância criogênica. O presente trabalho tem como objetivo avaliar a influência da sulfadiazina de prata, própolis, ácidos graxos essenciais e calêndula no tempo da cicatrização de feridas cutâneas padronizadas e induzidas pelo nitrogênio líquido em ratos. Utilizaram-se 40 ratos Wistar, divididos aleatoriamente em cinco grupos de oito animais cada: grupo vaselina (V), grupo sulfadiazina de prata (S), grupo própolis (P), grupo ácidos graxos essenciais (A) e grupo calêndula (C). Através da aplicação do nitrogênio líquido pela técnica do spray aberto, realizou-se a indução de duas feridas na região dorsal em segmentos paralelos de pele, uma no antímero direito e outra no esquerdo. A ferida direita recebeu o tratamento de acordo com os agentes tópicos escolhidos ou apenas com o veículo da pomada (vaselina sólida). A ferida esquerda recebeu a limpeza com solução cloreto de sódio 0,9% ou nenhum tratamento adicional. As aplicações tópicas foram realizadas duas vezes ao dia, durante 28 dias após a indução das lesões. Macroscopicamente, a cada dois dias, analisaram-se as medidas das lesões e calculou-se a área e a taxa de contração cicatricial das mesmas. No 28º dia pós-operatório, procedeu-se à coleta das biópsias para avaliação histopatológica e imuno-histoquímica, quanto à presença de células inflamatórias, intensidade de deposição de colágeno, densidade de mastócitos, proliferação epitelial e angiogênese. Com base nos resultados obtidos concluiu-se que: 1) o grupo própolis apresenta a maior taxa de contração das feridas, demonstrando diferença estatística significativa em relação ao grupo sem tratamento nas avaliações a partir do 6º dia pós-cirúrgico; 2) não se observa diferenças estatísticas significativas entre os grupos pesquisados quanto à proliferação epitelial, neovascularização e deposição de colágeno, nas avaliações histopatológicas e imuno-histoquímicas aos 28 dias de pós-operatório; 3) a terapia com os agentes tópicos ou, apenas, com a limpeza com solução cloreto de sódio 0,9% proporciona uma relevante evolução clínica das feridas frente a não intervenção no processo cicatricial. Sugere-se a necessidade de novos estudos com cicatrização de lesões causadas pela criocirurgia, no que diz respeito às ferramentas que podem ser usadas com o intuito de acelerar esse processo e melhorar a qualidade das cicatrizes.Cryosurgery has been used to treat different diseases of systems and organs in both human and veterinary medicine. Although treatment of skin disorders is the leading indication, adverse effects, such as delayed wound healing, large scars, esthetical deformation, and functional impairment, have been reported with administration of cryogenic substance. This study aims to evaluate the influence of silver sulfadiazine, propolis, essential fatty acids and calendula at healing time of cutaneous wounds that were standardized and induced by liquid nitrogen in rats. For that, forty Wistar rats were randomly divided in five groups of eight animals each: vaseline group (V), silver sulfadiazine group (S), propolis group (P), essential fatty acids group (A) and calendula group (C). Two parallel lesions were produced in the dorsal region of each rat through the application of liquid nitrogen by spraying technique. The right wound received treatment according to the chosen topical agents or only with ointment vehicle (solid vaseline). The left wound was just cleaned with a 0.9% sodium chloride solution or it received no additional treatment. Topical applications were carried out twice daily for 28 days after wound induction. Macroscopically, every two days, the wounds were measured to calculate their area and healing rate. On the 28th postoperative day, biopsies were performed for histopathological and immunohistochemical evaluations. Microscopic analysis included: presence of inflammatory cells, intensity of collagen deposition, mast cells density, epithelial proliferation and angiogenesis. By the obtained results, the study concludes that: 1) propolis group shows the highest wound contraction rate, with a statistical difference to the untreated group in all the evaluations performed after the sixth day of treatment; 2) there were no significant differences among groups regarding epithelial proliferation, neovascularization and collagen deposition; 3) therapy with topical agents or just a cleaning with 0.9% sodium chloride solution provides an important clinical evolution of wounds when compared to non-intervention in healing process. Lastly, this paper proposes that new studies on ways of accelerating and improving quality of the healing process following cryosurgery are necessary.
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Sathananthan, Saranya. "Modulating fibrin matrix properties via fibrin knob peptide functionalized microgels." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44905.
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Fibrin is the body's natural provisional matrix activated in response to vascular injury in which noncovalent knob:hole interactions between fibrin monomers lead to the assembly of fibrin for clot formation. In this study we aimed to exploit fibrin knob:hole affinity interactions with swelling, space filling microgels for the development of a potential bio-synthetic hybrid polymer system with hemostatic properties. Previous work has explored the inherent binding interactions of various fibrin knobs and their complementary polymerization holes, which have led to the development of fibrin knob peptide mimic (GPRPFPAC) with enhanced binding affinity for fibrin(ogen) holes. By coupling this enhanced fibrinogen binding peptide with a pNIPAm microgel system capable of being dynamically tuned and self-assembled, we hypothesized the specific and rapidly triggered formation of a bulk hydrogel in a wound environment (i.e. in the presence of fibrinogen). We found that at the peptide ligand density and concentrations of microgels used, that a rapid formation of a gel did not occur in the presence of fibrinogen alone. However with fibrinogen and thrombin, we found that fibrin network polymerization, structure, and viscoelastic properties were greatly altered in the presence of knob peptide-conjugated microgels.
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Jorge, Michelle Pedroza 1981. "Atividade cicatrizante do extrato bruto de Arrabidaea chica (Humb. & Bonpl.) verlot." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/309829.
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Orientadores: João Ernesto de Carvalho, Mary Ann Foglio, Lucia Tasca Gois RuizDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: As folhas de Arrabidaea chica (Humb. & Bonpl.) Verlot (Bignoniaceae), popularmente conhecida como Crajiru, são utilizadas na medicina popular como cicatrizante, antiinflamatória e no tratamento de cólicas intestinais. O presente trabalho descreve os efeitos cicatrizante, antiinflamatório, antiulcerogênico e antioxidante do extrato bruto metanólico das folhas de Arrabidaea chica. O extrato estimulou o crescimento de fibroblastos, in vitro, de forma proporcional à concentração utilizada com atividade similar à alantoina. Também estimulou a produção in vitro de colágeno de maneira semelhante ao ácido ascórbico. Nos ensaios de DPPH e Folin-Ciocalteau, o extrato bruto apresentou moderada ação antioxidante. A aplicação tópica do extrato bruto em modelos experimentais do processo cicatrizante in vivo reduziu em 96% a área cutânea ulcerada após dez dias de tratamento, enquanto o grupo salina apresentou redução de somente 36%. Em modelos de úlcera gástrica em ratos induzida por etanol, o extrato bruto de A. chica reduziu o índice de lesões em 90%. Apesar do uso popular em processos inflamatórios, esse extrato não reduziu o edema de pata induzido por carragenina nem o edema de orelha induzido por óleo de cróton em ratos. Esses resultados permitem concluir que o extrato bruto metanólico das folhas secas de Arrabidaea chica possui princípios ativos que ativam o processo cicatricial, através da proliferação de fibroblastos e síntese de colágeno, confirmando o uso popular cicatrizante desta espécie
Abstract: Arrabidaea chica (Humb. & Bonpl.) Verlot (Bignoniaceae) leaves, popularly known as Crajiru, are employed in folk medicine for wound healing, anti-inflammatory, and intestinal colic. Herein we report the in vitro and in vivo healing, antulcerogenic, antiinflamatory and antioxidant activities of Arrabidaea chica crude methanolic extracts. A. chica crude methanolic extract stimulated cell growth in a concentration dependent way and demonstrated similar effect as allantoin and vitamin C increasing in vitro collagen production. Also, A. chica crude extract demonstrated moderate scavenger effect (DPPH assay) and moderate reducing effect (Folin-Ciocalteau reagent). Wound healing experimental models in rats reduced in 96% the wounds size after ten days treatment, whereas saline group showed only 36% wound healing. Antiulcerogenic experimental models in rats showed gastroprotective activity, redution of 90%, by measuring ulceration lesion index (ULI). The Arrabidaea chica crude extract showed no antiinflamatory activity. The crude extract¿s efficiency seems to involve fibroblast growing stimulus and collagen synthesis both in vitro and in vivo, beyond the moderate scavenging activity and antiulcerogenic activity, corroborating with the folk use of this plant species
Mestrado
Ciencias Basicas
Mestre em Clinica Medica
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Dilika, Fikile. "The medicinal value of Amaryllidaceae and Asteraceae species used in male circumcision." Thesis, Connect to this title online, 2002. http://upetd.up.ac.za/thesis/available/etd-04112007-153554/.
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Meunier, Andreas. "Cyclooxygenase-2 inhibitors and knee prosthesis surgery." Doctoral thesis, Linköping : Department of Clinical and Experimental Medicine, Linköping University, 2008. http://www.bibl.liu.se/liupubl/disp/disp2008/med1077s.pdf.
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ANGELLOTTI, Giuseppe. "Sviluppo di spugne bioerodibili multifunzionali per la promozione di processi riparativi mediante il rilascio controllato di agenti antibiotici e antiossidanti. Utilizzo in chirurgia orale." Doctoral thesis, Università degli Studi di Palermo, 2023. https://hdl.handle.net/10447/580944.
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La salute delle strutture molli e dure del cavo orale è essenziale non solo per preservare le funzioni ad esse direttamente associate, ma anche per promuovere la salute generale dell’organismo. Tra le problematiche di maggiore interesse clinico a carico della cavità orale ritroviamo: i) le complicazioni post-operatorie che possono verificarsi a seguito di comuni avulsioni dentali che, se non trattate tempestivamente, possono sfociare in gravi parodontiti; ii) i fenomeni di osteonecrosi a carico di mascella e mandibola associate a trattamenti farmacologici nonché alla radioterapia; iii) il carcinoma orale a cellule squamose (OSCC) che è tra i più aggressivi tumori del collo e della testa, caratterizzato dal più basso tasso di sopravvivenza a 5 anni. Va inoltre presa in considerazione la posizione anatomica del cavo orale che, essendo facilmente accessibile dall’esterno, è suscettibile ad infezioni batteriche che possono compromettere uno stato di salute già debilitato e/o peggiorare la condizione clinica delle problematiche sopra citate. Nel trattamento delle affezioni del cavo orale è di fondamentale importanza ottenere una rapida remissione della sintomatologia, favorendo la rigenerazione del tessuto leso e prevenendo le complicazioni infettive mediante una terapia mirata, efficace e localizzata. Tuttavia, le strategie terapeutiche attualmente in uso sono spesso invasive e in alcuni casi meramente palliative (es. rimozione chirurgica del tessuto necrotico anche osseo), o spesso la necessità di ricorrere a terapie farmacologiche aggressive non scevre da effetti avversi anche gravi può contribuire ad un peggioramento di una condizione patologica preesistente.
Per superare gli inconvenienti dati dai trattamenti convenzionali, recentemente è stato proposto l’utilizzo di sostanze naturali di origine vegetale aventi comprovate proprietà terapeutiche benefiche (es. antiossidanti, antinfiammatorie, antitumorali, antibatteriche), capacità di stimolazione dei processi di rigenerazione tissutale, e soprattutto, effetti collaterali trascurabili. Tra le varie classi di composti naturali che potrebbero rispondere a tali requisiti, i polifenoli sono quella di maggiore interesse scientifico. Si tratta di un gruppo di molecole molto eterogeneo accomunato chimicamente dalla presenza di uno o più gruppi fenolici. Sebbene i polifenoli si trovino in molteplici fonti alimentari e le loro svariate proprietà benefiche siano ben note, il loro utilizzo in ambito clinico è ancora una sfida aperta a causa delle loro caratteristiche chimico-fisiche e farmacocinetiche generalmente sfavorevoli, quali instabilità chimica e fisica, quando soggette ai fenomeni ambientali come le radiazioni ultraviolette, temperatura elevata o pH fortemente acido o alcalino, scarsa solubilità in ambiente acquoso, elevata suscettibilità al metabolismo epatico e, quindi, bassa biodisponibilità a seguito di somministrazione orale. Per superare tali limiti e rendere somministrabili ed efficaci i polifenoli è quindi auspicabile la realizzazione di drug delivery platform o carrier in grado di incorporare efficacemente tali attivi, preservarne l’integrità strutturale e funzionale e modularne il rilascio al sito target. Inoltre, per promuovere la guarigione dagli stati patologici sopra elencati, può risultare utile la co-somministrazione di polifenoli ed antibatterici tra quelli già utilizzati in chirurgia orale. Tenendo in considerazione queste premesse nel presente lavoro di dottorato sono stati realizzati innovativi sistemi di veicolazione capaci di incorporare polifenoli quali Curcumina, Quercetina e Resveratrolo da soli o in co-somministrazione con antibiotici quali il Metronidazolo e la Ciprofloxacina, per il trattamento localizzato delle suddette patologie associate al cavo orale.
Una strategia per la veicolazione dei polifenoli consiste nella loro incapsulazione in sistemi micro e nanoparticellari. A tal fine sono state realizzate microparticelle polimeriche contenenti Resveratrolo con la tecnica dello Spray Drying, ottimizzando accuratamente i parametri operativi al fine di ottenere particelle sferiche, di dimensione omogenea ed uniformi in termini di contenuto in attivo. Tale strategia ha consentito la completa amorfizzazione del Resveratrolo, incrementandone notevolmente la solubilità in ambiente acquoso, e promuoverne la permeabilità attraverso la mucosa sublinguale.
I Carrier Lipidici Nanostrutturati (NLC), costituiti da particelle di dimensioni nanometriche, si sono rivelati un altro sistema di veicolazione dei polifenoli particolarmente promettente, proprio grazie alla loro natura lipidica che ben si è adattata alle caratteristiche chimico-fisiche dei polifenoli. Un’attenta selezione dei componenti lipidici e del bilanciamento degli stessi in relazione al tipo ed alla quantità di polifenolo da incapsulare, ha consentito la preparazione di miscele omogenee, aventi temperatura di rammollimento opportuna (stabilità, storage e maneggevolezza) ma soprattutto contenenti il polifenolo nella sua forma amorfa. Sono stati pertanto preparati e caratterizzati diversi sistemi NLC contenenti rispettivamente Curcumina, Quercetina e Resveratrolo. L’ottimizzazione della tecnica di preparazione top-down ad alta energia caratterizzata da omogeneizzazione seguita da sonicazione ad alte frequenze, ha portato alla produzione di nanoparticelle riproducibili ed omogenee (<500 nm, PDI < 0.600), caratterizzate da un’elevata efficienza di incapsulazione (>95%) ed in grado di controllare il rilascio degli attivi secondo cinetiche ben definite. Per consentire la co-somministrazione dei polifenoli (lipofili) con gli antibiotici precedentemente menzionati (idrofili), sono stati ulteriormente realizzati dei sistemi nanocompositi sotto forma di spugne bioerodibili, costituite da una matrice polimerica biocompatibile e bioerodibile (a base di Chitosano o Acido Ialuronico, e PVP K90) all’interno della quale sono state intrappolate le nanoparticelle lipidiche. I nanocompositi, essendo formulazioni polverulente, hanno mostrato diverse caratteristiche favorevoli, tra cui: omogeneità, elevata porosità, capacità di promuovere l’accumulo degli attivi nei tessuti del cavo orale ed elevata stabilità nel tempo, preservando così i polifenoli dalla degradazione. Inoltre, la “trasformazione” delle dispersioni acquose di NLC in un sistema anidro porta all’ottenimento di una polvere secca estremamente semplice da manipolare ed applicare, consentendo di dosare i principi attivi in modo accurato e riproducibile. Studi in vitro, hanno dimostrato, inoltre, la citocompatibilità delle spugne bioerodibili a base di Curcumina, coì come la citocompatibilità delle NLC cariche di Resveratrolo con i fibroblasti murini, mentre le spugne a base di Quercetina e Ciprofloxacina hanno evidenziato proprietà antibatteriche e antibiofilm nei confronti dello Staphilococcus aureus superiori all’antibiotico in forma libera.Parallelamente, è stata impiegata la tecnica della stampa 3D per la realizzazione di scaffold polimerici carichi sia di Curcumina, in cui l’aggiunta di beta-tricalcio fosfato (bioceramica), è stata in grado di influenzare positivamente le caratteristiche dello scaffold, aumentandone la porosità e promuovendo la stabilità della Curcumina in fase di preparazione.
In conclusione, il lavoro di ricerca svolto ha portato allo sviluppo tecnologico, da una parte, di valide ed efficienti delivery platform nano- e micrometriche per la veicolazione dei polifenoli e, dall’altra, alla produzione di sistemi di drug delivery macroscopici (nanocompositi e scaffold) potenzialmente utili per il trattamento delle patologie del cavo orale.
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Zhong, Yinghui. "Development and Characterization of Anti-Inflammatory Coatings for Implanted Neural Probes." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/19760.
Full textAbstract:
Stable single-unit recordings from the nervous system using microelectrode arrays can have significant implications for the treatment of a wide variety of sensory and movement disorders. However, the long-term performance of the implanted neural electrodes is compromised by the formation of glial scar around these devices, which is a typical consequence of the inflammatory tissue reaction to implantation-induced injury in the CNS. The glial scar is inhibitory to neurons and forms a barrier between the electrode and neurons in the surrounding brain tissue. Therefore, to maintain long-term recording stability, reactive gliosis and other inflammatory processes around the electrode need to be minimized.
This work has succeeded in the development of neural electrode coatings that are capable of sustained release of anti-inflammatory agents while not adversely affecting the electrical performance of the electrodes. The effects of coating methods, initial drug loadings on release kinetics were investigated to optimize the coatings. The physical properties of the coatings and the bioactivity of released anti-inflammatory agents were characterized. The effect of the coatings on the electrical property of the electrodes was tested. Two candidate anti-inflammatory agents were screened by evaluating their anti-inflammatory potency in vitro. Finally, neural electrodes coated with the anti-inflammatory coatings were implanted into rat brains to assess the anti-inflammatory potential of the coatings in vivo. This work represents a promising approach to attenuate astroglial scar around the implanted silicon neural electrodes, and may provide a promising strategy to improve the long-term recording stability of silicon neural electrodes.
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Pasini, Marcela Mozzaquatro. "AVALIAÇÃO DE DIFERENTES FORMULAÇÕES DE AZUL DE METILENO NA TERAPIA FOTODINÂMICA EM DOENÇA PERIODONTAL INDUZIDA EM RATOS." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/6138.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis study aimed to evaluate the histological effect of different formulations of Methylene Blue (MB) used in antimicrobial Photodynamic Therapy (aPDT) as adjuvant to conventional treatment, on gingival collagen fibers in the treatment of periodontal disease induced in rats. In this study were used 120 male rats (Rattus Novergicus, Wistar lineage). The periodontitis was induced by placing a ligature on right mandibular first molar in 105 rats. After 7 days, they were removed and the animals were randomized in 5 groups: NC negative control; PC positive control (no treatment); SRP - scaling and root planning (SRP) and periodontal pocket irrigation with saline solution; aPDT SRP + aPDT (with MB 0,01% dissolved in water + laser); aPDT/ethanol SRP + aPDT (with MB 0,01% dissolved in solvents containing ethanol 20% + laser). The NC animals received neither periodontitis induction nor treatment. Five animals of NC and PC and ten animals of SRP, aPDT and aPDT/ethanol are euthanized 7, 15 and 30 days after treatment. Gingival samples were collected to the quantification of collagen fibers and descriptive analysis of collagen type I and III proportion and organization. Data were analyzed with ANOVA and multilevel Poisson regression analysis. The animals of NC, PC, SRP, aPDT and aPDT/ethanol showed percentage of collagen fibers area of 67,99%, 45,71%, 58,39%, 71,70% and 72,37%, respectively, but no statistical difference was seen in aPDT and aPDT/ethanol; the collagen fibers area was higher at 30 days (71,37%) than at 7 days (60,25%) and at 15 days (63,12%) after treatment, showing statistical difference only at 30 days (ANOVA). Considering multivariate Poisson regression analysis, aPDT and aPDT/ethanol showed 6% higher rate of collagen fibers organization when compared to NC (p<0,05); this organization increased 5% at 15 days after treatment and 19% at 30 days when compared to 7 days (p<0,05). The action of different formulations of MB was similar concerning the quantity and organization of gingival collagen fibers, presenting higher collagen type I quantity, parallel and dense alignment at 30 days after treatment. According to the experimental model used in this study, the ethanol presence in MB formulation doesn t interfere on collagen fibers quantity and quality of collagen fibers in periodontal wound healing. This study suggests the aPDT could be a promising alternative to periodontal disease treatment as adjuvant to conventional treatment.
Este estudo objetivou avaliar histologicamente o efeito de diferentes formulações de Azul de Metileno (AM), na Terapia Fotodinâmica antimicrobiana (TFDa), como adjuvante ao tratamento periodontal convencional, sobre as fibras colágenas do tecido gengival no tratamento da doença periodontal induzida em ratos. Neste estudo, foram utilizados 120 ratos machos (Rattus Novergicus, linhagem Wistar). A periodontite foi induzida pela colocação de ligaduras no molar inferior direito em 105 ratos. Decorridos 7 dias, as ligaduras foram removidas e os animais foram randomizados em 5 grupos: CN - controle negativo; CP - controle positivo (sem tratamento); RAR - raspagem e alisamento radicular (RAR) e irrigação da bolsa periodontal com solução salina; TFDa - RAR + TFDa (com AM a 0,01% dissolvido em água + laser); e TFDa/etanol - RAR + TFDa (com AM a 0,01% dissolvido em solventes contendo etanol a 20% + laser). Os animais do CN não foram submetidos à indução de doença ou tratamento. Cinco animais de CN e CP e dez animais de RAR, TFDa e TFDa/etanol foram eutanasiados em 7, 15 e 30 dias após os tratamentos. Amostras de tecido gengival foram coletadas para quantificação das fibras colágenas e análise descritiva da proporção e organização dos tipos I e III de colágeno. Dados foram analisados com ANOVA e análise multinível de Regressão de Poisson. Os animais de CN, CP, RAR, TFDa e TFDa/etanol mostraram percentual de área das fibras colágenas de 67,99%, 45,71%, 58,39%, 71,70% e 72,37%, respectivamente, porém nenhuma diferença estatística foi observada entre TFDa e TFDa/etanol; a área das fibras colágenas foi maior aos 30 dias (71,37%) do que aos 7 dias (60,25%) e aos 15 dias (63,12%) após o tratamento, apresentando diferença estatística somente aos 30 dias (ANOVA). Considerando a análise multivariada da Regressão de Poisson, TFDa e TFDa/etanol apresentaram uma taxa 6% maior de organização das fibras colágenas quando comparados ao CN (p<0,05); tal organização aumentou 5% aos 15 dias após o tratamento e 19% aos 30 dias, quando comparados aos 7 dias (p<0,05). A ação das diferentes formulações do AM foi semelhante no que diz respeito à quantidade e organização das fibras colágenas do tecido gengival, apresentando maior quantidade de colágeno tipo I, com alinhamento paralelo e denso aos 30 dias após o tratamento. De acordo com o modelo experimental utilizado neste estudo, a presença do etanol na formulação do AM não interfere na quantidade e na qualidade das fibras colágenas frente ao processo de cicatrização periodontal. Este estudo sugere que a TFDa pode ser uma alternativa promissora para o tratamento da doença periodontal como adjuvante ao tratamento convencional.
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Mncube, Khulekani. "Characterisation of Absorbatox™ as a wound healing agent." Diss., 2013. http://hdl.handle.net/2263/31616.
Full textAbstract:
Introduction: Chronic wounds are a great burden to care-givers and patients alike and are the main cause of many preventable amputations. Such wounds are treated with wound dressings but providing a wound environment that is conducive to proper wound healing is not always possible with such dressings. Absorbatox™ is a natural zeolite that has been manipulated to increase its cationic exchange capacity and has its main functionality as a potential wound healing agent in its strong capillary action. This quality enables the zeolite to absorb excess wound exudate and thus prevent wound infection and maceration. Absorbatox™ was characterised to determine its effects on wound healing. Methods: The physical characterisation of two grades of Absorbatox™ - granular and micronised - was conducted using nitrogen adsorption to determine pore size and surface area, and laser particle sizing to determine the particle sizes of the Absorbatox™ particles. Full-thickness wounds of 8 x 8 mm were created on the backs of pigs and treated with Absorbatox™, a positive and a negative control. The wound dimensions were measured and recorded. The wounds were then excised on selected days of each phase of wound healing and fixed in formalin. The wound sections were analysed by mass spectrometry imaging and abundant wound proteins were identified from the tryptic digests using BLAST against the Swiss-Prot database. Results: The surface areas of the micronised and granular Absorbatox™ were 14.43 and 11.23 m2/g, respectively. The micronised Absorbatox™ particle sizes ranged between 0.8 µm to approximately 300 µm with an average pore diameter of 28.2 nm. The granular Absorbatox™ particle sizes ranged between 2 µm and 875 µm with average pore diameters of 43.8 nm. Absorbatox™ showed better wound healing by delaying wound contraction and causing more rapid shallowing of the wound depths compared to the negative control. The difference observed in the wound healing rates of the Absorbatox™-treated and positive control groups were statistically significant and the histological evaluations of the wounds treated with Absorbatox™ showed wound closures that were associated with qualities that more closely resembled normal, healthy tissue than the positive control wounds. The protein activity in the trypsin-digested tissue including within the wound area and the surrounding healthy tissue was successfully imaged using MALDI-MSI. BLAST software was used at an e-value of 30 to identify possible proteins from the tryptic digests and were identified as proteins involved in wound healing. Discussion: Micronised Absorbatox™ treated wounds showed more rapid healing than the other treatments most likely due to the smaller particles and pores which results in strong capillary action to absorb excess exudate. Mass spectrometry imaging allowed monitoring of the protein fluctuations that occur during wound healing. The proteins detected were then identified using BLAST and MASCOT database comparison tools which identified that the abundant proteins detected by mass spectrometry were not those typically observed in wound healing but rather those involved in molecular aspects of wound healing like nerve regeneration, cell proliferation, survival, and migration.Dissertation (MSc)--University of Pretoria
Pharmacology
unrestricted
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DWIVEDI, RAMAN. "MICROENCAPSULATION OF HEALING AGENT FOR USE IN POLYMER COATINGS." Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14932.
Full textAbstract:
Different healing agents, namely unsaturated polyester and epoxy were encapsulated in polystyrene by physical encapsulation technique. The effect of operating parameters on the microcapsule dimensions and morphology was established by SEM imaging. Thermal and structural properties of the microcapsules were determined by TGA and FTIR respectively. Core content of PS encapsulated microcapsules was found to be 45 3%. Epoxy and USP were encapsulated in urea-formaldehyde microcapsules by emulsion polymerisation process. The core content of the microcapsules was determined by solvent extraction method and was found to be 58 4%. Latent hardener (copper complex of 2-methyl imidazole) was synthesized by the reaction of copper chloride with 2 methyl imidazole. Self-healing composites are also prepared by dispersing varying amount of microcapsules (10-30% w/w) in the matrix. The impact strength was found to decrease with introduction of microcapsules in the composition. Latent hardener was used as a curing agent to effect self healing in epoxy compositions containing epoxy encapsulated in UF microcapsules. Self healing efficiency was determined as the ratio of impact strength of the samples before and after healing. ~67% efficiency could be achieved using copper complex as the latent hardener system. Self healing was also demonstrated in compositions containing unsaturated polyester encapsulated in UF microcapsules. Although USP underwent thermal self curing, the temperature required could be brought down significantly by using AIBN as the free radical initiator. Self healing efficiency of ~103% could be achieved using AIBN as the curing agent.
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Mwangi, Justus Mbogo. "Divorcees' problem : the church as a healing agent in counselling of divorcees." Thesis, 1998. http://hdl.handle.net/10413/4491.
Full textAbstract:
The objective of this research study is to investigate the problems of the divorced Christians within the Anglican Diocese of Kirinyaga in Kenya. A selection was made of some the divorced Christians in this diocese who even after their separation and divorce remained in the Church. The divorced Christians in this study were observed to have many more
problems than ordinary Christian people. Their failure to survive their marriage made them feel desperate, tending towards a sense of personal failure. It was hypothesized that divorcees experience being sidelined in the Church, thus causing them physical and psychological emotions which affect them and label them as people who are unpardonable. Jack Dominian (1979), in search of information leading to the breakdown of
marriages, has observed that the Christian Churches' teaching on sexuality and marriage has been a factor contributing indirectly to the breakdown of
marriages and specifically to divorce. He also confirmed that another important contributing factor is the background of the partners. With this in mind the Christian Churches will want to do everything possible to save marriages. Therefore, the Churches have to be properly prepared and
equipped for undertaking the challenges involving in building a worthy marriage. At the end of this research study the emphasis on marriage counselling is appealed to as a worthy tool to guide people towards a stable marriage. The dissertation commences with chapter one as an introduction which defines the objectives, motivation and the hypothesis to be tested. The literature review is tabled and is followed by definition of the terms so as to make the reader familiar with their usage. Finally, the chapter closes with the structure of the study. Chapter two deals with the methodology, explaining the sample and the development of the tool. The survey and all procedures are explained. Chapter three is divided into three parts. Part one introduces Agikuyu marriage and divorce, part two brings a theological review of divorce problems in the scriptures and part three brings a challenge to the missionary endeavours in the Anglican Diocese of Kirinyaga. It deals with the tensions created by the efforts of the Western missionaries and the Church as they came up against the African traditional heritage. Chapter four brings out the results of the methodological work. Hypothesis analysis is done and the interpretation given. The findings are given for and against the hypothesis. Discussion of the findings is done and then a conclusion is made. Chapter five is divided into three parts. First, a few ideas arising from the findings are discussed at length.The second part is the way forward which suggests possible ways in dealing with divorcees and enhancing a stable marriage. The final part carries the concluding remarks as a summary of the research study.Thesis (M.Th. ; School of Theology)-University of Natal, Pietermaritzburg, 1998
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Cai, Ren-zhi, and 蔡仁智. "Implementation of Android-Based Multi-Agent Systems for Self-Healing Distribution Systems." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/72e9nz.
Full textAbstract:
碩士國立臺北科技大學
自動化科技研究所
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This thesis proposed a distributed multi-agent system for distribution system service restoration. The system consists of switch and feeder agents. Each agent maintains its own information. Agents can operate independently, and talk to other agents for exchanging information. Decision makes by agents are done parallelly. Parallel processing can speed up the decision making. The final switch operations are done by switch agents. As the decision is performed parallelly, the performance service restoration can be improved. This thesis utilizes JADE as the multi-agent development platform to development a self-healing system for distribution systems. The platform consists of Personal Computers（PCs）and Android platforms. Switch and feeder agents are assigned to PCs and Android platforms. Communications between PCs, between Android platforms and between PCs and Android platforms are developed. In order to exchange information on different platforms, ontology is implemented in this thesis to avoid context confusions. Due to portability and easy development of human machine interface system, Android platform is chosen for the development of the Multi-Agent Self-Healing Distribution Systems. The simulation results show that the proposed system is able to find an adequate switch plan for service restoration by exchange information between agents.
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"Development of an agent-based model to recapitulate murine patellar tendon healing as a function of age." Tulane University, 2021.
Find full textAbstract:
archives@tulane.eduThe patellar tendon transmits loads from the quadriceps to the tibia promoting locomotion. The main etiological factor behind patellar tendinopathies is thought to be excessive loading and unloading during athletic activity (Pearson & Hussain, 2014). The extracellular matrix (ECM) composition and fibroblast-like tenocytes dictate tendon’s uniaxial mechanical properties (Kannus, 2000). Following injury, a flood of inflammatory cells and spike in certain gene expressions work together to remove damaged tissue, trigger fibroblast proliferation, and deposit a provisional collagen matrix (Thomopoulos et al., 2015). Despite these processes, healed tendons demonstrate significant functional deficits (Mienaltowski et al., 2016). Moreover decrease in cell migration and fiber alignment with age further hampers healing outcomes(Dunkman et al., 2013). Efforts to restore tendon function are impeded by a lack of understanding of the early healing process, which may be age- and sex-dependent (Fryhofer et al., 2016; Mienaltowski et al., 2016). The tendon healing process can be further understood using an agent-based model (ABM). ABMs simulate individual agents and the interactions between them and their environment. This approach has the advantage of building complexity from the ground up, mimicking the underlying tendon physiology (Conte & Paolucci, 2014). Therefore, the objectives of this study were to 1) formulate a literature based ABM of murine patellar tendon healing with varying initial conditions to recapitulate changes observed with aging, and 2) Conduct simulations to determine whether ABM recapitulated salient features of healing, and to make predictions about healing outcomes.
1
Jordan Robinson
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Vediappan, Rajan Sundaresan. "Modifying Post-Surgical Wound Healing." Thesis, 2021. http://hdl.handle.net/2440/130740.
Full textAbstract:
“Surgery is a profession defined by its authority to cure by means of bodily invasion. The brutality and risks of opening a living person's body have long been apparent, the benefits only slowly and haltingly worked out”, says Atul Rawande on reviewing 200 yrs. of Surgery as a specialty in NEJM. My research focuses on working out these benefits, specifically looking at reduction of scar tissue formation in ENT, Abdominal & Spine surgery. Scar tissue formation is an outcome of healing process that can be excessive due to inflammation or infection and thereby has the ability to curtail the benefits or warrant revision surgery. Multiple strategies have been tested and employed thus far and none have given favourable results without causing additional harm or economic burden in health care costs. I propose to use a hydrogel synthesized by combining Chitosan and Dextran aldehyde -Chitin is an exoskeleton extracted polymer and Dextran Aldehyde a sugar, with added noveldrugs Deferiprone and Gallium Protoporphyrin providing additional anti scaring and antibiotic properties which could potentially augment the healing properties of the gel. I have conducted 3 types of studies. There are 2 animal studies and a Phase 1 Human clinical trial. The animal studies are an abdominal surgery rat model and a spine surgery sheep model. These studies show the safety and efficacy of this chitogel-drug combination at various dosages and illustrate the healing benefits of gel-drug combination.Thesis (Ph.D.) -- University of Adelaide, Adelaide Medical School, 2021
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Kok, Jacobus (Kobus). "Siekte en gebrokenheid teenoor genesing en restourasie in Johannes (Afrikaans)." Thesis, 2008. http://hdl.handle.net/2263/29292.
Full textAbstract:
In this dissertation the healing acts of Jesus in John are investigated against the ancient Mediterranean socio-religious and cultural background in which it realized. All sickness and healing realities realize within a particular socio-cultural context and may differ significantly within different cultures. For example, less than one hundred years ago depression was not diagnosed as an illness and there existed no therapeutic processes for the disease. When one investigates ancient healing narratives which tell of sickness realities almost 2000 years ago, before the dawn of the Western Bio-Medical research system and modernism, one must remember that the sickness realities of that time will differ to a great extent from the modern project‘s sickness realities and its constructs. The researcher must in other words be very sensitive about anachronistic misinterpretations and ethnocentrism - that is, a reductionistic view of sickness (and other) realities through your own worldview. For this reason the term sickness is used as an umbrella term, and a distinction is made between the curing of a disease and the healing of an illness. The word group curing and disease are words that are used in the Western Bio-Medical world, and are also deeply imbedded within the modernistic philosophical worldview. On the other hand the word group healing of an illness is more inclusive in the sense that it is sensitive to sickness realities as experienced and constructed in ancient Mediterranean societies. In the first century ancient Mediterranean temple oriented Judaism for example, a particular disease (like skin disease), unlike today, also had negative socio-religious implications for the afflicted person which sometimes resulted in marginalization and status deconstruction. Turning to John‘s healing narratives it should also be taken into account that his healing acts are presented as σημετα that is, signs which illustrate that Jesus is the Son of God, the source of life (cf. John 20:30-31; 10:32; 6:14). The question to be answered is, in what way does John present the healing narratives in order to illustrate that Jesus is the true source of Life (cf. John 1:4). The thesis is thus developed that John presents sickness realities that closely represent ¯"death”, crisis, disorientation, brokenness and loss of life possibilities within the ancient Mediterranean symbolic universe. John then presents Jesus as the divine transformation Agent, who restores and recreates life possibilities after a transformational interaction with the sick person. It is also argued that John‘s understanding of healing is not to be limited to the traditional Western Biomedical paradigm revolving around the curing of disease but also includes a view of Jesus‘ role as healer and restorer of spiritual brokenness, a tradition which originated in the Old Testament. The narrative regarding the discussion between Jesus and the Samaritan woman is used as an example of a situation in which Jesus offers someone the gift of life and spiritual restoration or healing which resulted in the representation of reality. Lastly it will be argued why the resurrection could be understood as a Johannine σημετον and also be interpreted as the culminating healing act in John‘s Gospel, illustrating that Jesus is the true source of life in abundance (cf. John 1:4; 10:10).Thesis (PhD)--University of Pretoria, 2008.
New Testament Studies
PhD
Unrestricted
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(8306043), Yen Hao Chiao. "SCREENING FOR ALKALINE RESISTANT SPORE FORMING BACTERIA AS CONCRETE HEALING AGENTS." Thesis, 2020.
Find full textAbstract:
In order to find suitable bacteria as concrete healing agents, we examined a total of 50 bacterial isolates from an alkaline soil sample. These isolates were subsequently tested for sporulation rates, ability to induce calcium carbonate precipitation, tolerance to alkaline conditions, as well as their capacity to heal cracks in mortar samples. Of the 50, two bacterial isolates showed promising results across all these test categories. These isolates were identified as Bacillus horneckiae and B. kochii. Both were able to grow on LB agar at a pH of 10, within 5 days had sporulation rates over 90% on the AR2A agar plates, and precipitated calcium carbonate on B4 agar plates.
Both B. horneckiae and B. kochii had preferences for high alkaline environments. The OD 540nm readings of these two bacteria in pH 9 and 10 LB broths were significantly higher than the readings of their counterparts in pH 8 LB broth after 48 h of incubation. The growth of B. horneckiae and B. kochii in different concentrations of YE broths were tested. These two bacteria both had worse growth in 0.5 and 1% YE broths than in 2% YE broth. The spores of B. horneckiae and B. kochii were also tested for germinations in the same test environments. Results showed that either high pH or low nutrient levels did not have many impacts on spore germinations of these two bacteria.
Calcium carbonate precipitation from these two bacteria were quantified. Bacillus horneckiae and B. kochii reduced approximately 980 and 650 ppm of free Ca2+ ion respectively from a 1/10 LB broth containing 2500ppm of Ca2+ within 7 d and precipitated CaCO3.
The mean viable counts of B. horneckiae and B. kochii decreased 1.2 and 1.5 orders of magnitude respectively in the first 24 h, dropped additional 0.6 and 0.4 orders of magnitude between day 1 and 14, and then, remained constant between day 14 and 28 after being mixed in mortar samples. Healing abilities were tested by incorporating bacterial spores in mortar samples. Cracks up to 0.25 mm were healed in mortar samples containing B. horneckiae or B. kochii spores. All the results suggested that both the bacterial isolates, B. horneckiae and B. kochii, may be used as bacterial healing agents in self-healing concretes.
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Moharana, Soumya Ranjan. "An in silico exploration of novel antifibrotic agents for wound healing." Thesis, 2013. http://ethesis.nitrkl.ac.in/4671/1/109BT0026.pdf.
Full textAbstract:
A breach in epithelial lining from trauma or disease leads to wound formation. Wounds can vary in depth and can be incised, chopped, lacerated or a complex type depending upon the inducing agent and the direction of force applied. An untreated wound follows the natural course of healing that comprises of four phases. Prior to remodeling, the final phase in wound healing, proliferation phase initiates when the fibroblasts start depositing new extracellular matrix. Sometimes, the remodeling is compromised and there is excessive matrix deposition. This phenomenon is termed fibrosis. A number of signal transduction pathways orchestrate the wound healing and a disparity in the interaction leads to fibrosis. Transforming Growth Factor Beta (TGF-Beta) pathway acts as a hub in the whole interaction of wound healing and an abnormal response in its receptor has been confirmed to be the root cause of fibrosis. In the current project, TGF-Beta receptor was investigated as the target protein to alleviate fibrosis using bioinformatics tool. Briefly, the structures of TGF-Beta receptors were retrieved from PDB. A series of natural and synthetic drugs were searched and the corresponding structures were retrieved from PUBCHEM database. Ligand-receptor docking was done using Swiss-dock software. The structure of best docked ligand i.e. Alpha-tocopherol was modified in ChemSketch followed by docking. Both virgin and the modified Alpha-tocopherol can act as novel drug against excessive fibrosis; however it needs final validation in vitro and in vivo.
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TRIPATHI, MANORAMA. "INVESTIGATING THE INFLUENCE OF MICROENCAPSULATED HEALING AGENTS ON THE PROPERTIES OF EPOXY THERMOSETS." Thesis, 2017. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16140.
Full textAbstract:
The primary motivation behind the present research work is to study the effect
of inclusion of healant loaded microcapsules on specific properties (thermal,
structural and mechanical) of a representative epoxy thermoset. In addition, we also
explore alternate chemistry for introducing self healing functionality in epoxy
composites. Two distinct healing systems have been investigated, namely
cycloaliphatic epoxy and unsaturated polyester. The healants were encapsulated in
urea-formaldehyde microcapsules by adopting an in-situ dispersion polymerization
route and in polystyrene shell through solvent evaporation process. The effect of
operating parameters particularly stirring speed on the particle size distribution has
been studied. Under optimal conditions, the core content of the epoxy loaded
microcapsuleswas found to be 65 ± 4%for microcapsules prepared by dispersion
polymerization route and 38 ± 2%for microcapsules prepared using solvent
evaporation route.
It is to be noted that the healing efficiency is strongly influenced by the
internal microstructure of the microcapsule and we also developed an analytical
model for predicting the amount of healant released in the event of microcapsule
rupture. In microcapsules possessing “reservoir” type microstructure, the healant
exists as a single droplet, where the entire content is expected to be released upon
rupture. On the other hand, in monolithic microcapsules, the healant is dispersed in
the form of discrete micro-droplets, and only the healant available within the cracked
microcapsule is expected to be released and cause healing. Our model predicted that
significantly lower amounts of healant is released in monolithic microspheres in
comparison to reservoir microcapsules, especially when the micro-droplet dimensions
and core content, both are low.
V
Triethylenetetramine (TETA) hardener was encapsulated by adopting two
methods, namely interfacial polymerization and physical entrapment technique. The
effects of experimental parameters, namely reaction temperature (50-75°C), stirring
speed (400-700 rpm) and epoxy: amine concentration ratio (10:1.2-10:4.3) on the
microcapsule properties was investigated. A polymeric surfactant was used to
stabilize the suspension in order to modulate the particle size distribution of the
resultant microcapsules. Highest encapsulation efficiencies resulted when the
reaction medium was maintained at 70°C under a stirring speed of 600 rpm, while
maintaining an epoxy: amine ratio of 10:3.2. The microcapsule dimensions and core
content could be tailored, following the interfacial polymerisation route. Under
optimal conditions, spherical microcapsules with 100 % yield and 12% core content
were obtained.
Physical entrapment approach was also explored for the immobilisation of
amine hardener in mesoporous silica. For this purpose, mesoporous silica (SBA-15)
was synthesised using polymer-templated technique and employed as a substrate for
immobilization. Vacuum infiltration of TETA led to its entrapment within the porous
structure of SBA-15 with loadings as high as 5g/g, which could be attributed to
hydrogen bonding and acid–base interactions.
The curing kinetics of self-healing epoxy compositions was investigated by
non-isothermal differential scanning calorimetric (DSC) studies. Epoxy loaded
microcapsules and immobilised amine was dispersed into epoxy resin, and cured
using TETA. DSC studies revealed the autocatalytic nature of epoxy curing, which
remained unaltered due to addition of the fillers responsible for introducing self
healing functionality. The kinetic parameters of the curing process were determined
using both Friedman and Kissinger–Akahira–Sunose (KAS) method. The activation
VI
energy at different degree of conversion (E ) was found to decrease with increasing
degree of cure ( ). Although urea-formaldehyde possess secondary amine
functionalities, which have the potential to react with the epoxy groups, no significant
differences in the curing kinetics of the base resin were observed.Kinetic parameters
were used to predict the curing behaviour of compositions at higher heating rates
using KAS method. As expected, the onset curing temperature (Tonset) and peak
exotherm temperature (Tpeak) of epoxy shifted towards higher temperatures with
increased heating rate; however introduction of fillers do not affect these
characteristic temperatures significantly. Also, the overall order of reaction does not
vary significantly. The results suggest that although 2° amino groups are available
with the urea-formaldehyde (UF) resin, these do not directly participate in the curing
reaction, as the primary amino groups in TETA are more easily accessible.
To evaluate the effect of self healing additives on the mechanical properties
and healing efficiency, epoxy composites containing UF and PS microcapsules (5
30%, w/w) were prepared by room temperature curing and their mechanical
behaviour and healing efficiency was studied under both quasi-static and dynamic
loadings. The tensile strength, modulus and impact resistance of the matrix was found
to decrease with increasing amount of microcapsule in the formulation, the
detrimental effect being less pronounced for polystyrene microcapsules due to its
monolithic internal microstructure. Morphological investigations on the cracked
surface revealed features like crack pinning, crack bowing, microcracking and crack
path deflection, which were used to explain the toughened nature of microcapsule
containing epoxy composites.
VII
Healing efficiency was quantified in terms of the ratio of impact strength
before and after healing. For the purpose of validation of the developed analytical
model, composites were prepared using epoxy encapsulated microcapsules with
varied internal structures. Ni and Cu-imidazole complexes were prepared for use as
latent hardeners for epoxy. Both the imidazole-metal complexes could effectively
cure the epoxy released from within the microcapsules in the event of damage
followed by thermal treatment. In line with our predictions, the extent of healing was
much lower in the case of samples containing monolithic microcapsules. At 20% w/w
microcapsule loadings, healing efficiencies close to 60% was observed upon
introduction of reservoir type microcapsules, while under similar loadings, only 10%
healing could be evidenced in the presence of monolithic microcapsules.
For reservoir type microcapsules, complete healing (efficiency ~ 100±2%)
could be effected at 30% microcapsule loading, in the presence of metal imidazole
complexes. In comparison, the complete healing was evidenced at relatively lower
microcapsule loading (20%, w/w) when amine immobilised SBA-15 was used.
The potential of encapsulated unsaturated polyester resin (USP) towards
introduction of healing functionality was also explored. USP was encapsulated in
urea-formaldehyde shell and polystyrene shell by dispersion polymerization and
solvent evaporation technique respectively both resulting in the formation of free
flowing microcapsules. Calorimetric studies confirmed the chemical activity of the
encapsulated USP, which spontaneously polymerised in the presence of a free radical
initiator, 2,2‟-Azobis(2-methylpropionitrile) (AIBN), at temperature as low as 80°C.
Temperature triggered healing of epoxy-microcapsule composites was performed at
110° C and healing efficiency was quantified as the ratio of impact strength of healed
and virgin specimens. The same was found to increase with increasing amount of
VIII
microcapsule in the formulation and reached a maximum (100 ± 2%) at 20% (w/w)
loading. Fractographic analysis of the surface revealed the flow pattern of chemically
active polyester resin from the ruptured microcapsules, which subsequently cured in
the presence of AIBN available within the matrix.
50
Sefat, Farshid. "Transforming Growth Factor Beta (TGF-β): Natural Curing Agents for Repair." 2014. http://hdl.handle.net/10454/11142.
Full textAbstract:
yesThere are various techniques to enhance tissue regeneration via the application of growth factors to the site of regeneration to induce cells to proliferate, differentiate and regenerate. Generally, direct application of growth factors has little effect [1] because the growth factor diffuses out from the site of regeneration very quickly. This is a problem that can be solved by a controlled release of growth factor at the site of action over a long period of time by use of a bioabsorbable scaffold. Growth factors are protein based molecules in the body which are produced by cells and attach to the cell surface. Growth factors bind to membrane receptors, which in turn activate an intracellular signalling pathway. This will activate or inhibit a gene causing either an up regulation or down regulation of a gene product, which then alters the cells behaviour.