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1
Jayasekera, Rasika. "Condoms behind bars barriers to barrier protection /." [New Haven, Conn. : s.n.], 2008. http://ymtdl.med.yale.edu/theses/available/etd-12022008-141338/.
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Gunnarsson, Niklas. "Barrier options." Thesis, Uppsala University, Department of Mathematics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-122338.
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Fröjdh, Christer. "Schottky barriers and Schottky barrier based device on Si and SiC /." Sundsvall, 1998. http://www.lib.kth.se/abs98/froj0302.pdf.
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Jonas, Hartman. "Hemicellulose as barrier material." Licentiate thesis, KTH, Fibre and Polymer Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3907.
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<p>Polysaccharides constitute an important source of raw materials for the packaging industry today. Polysaccharides have good natural barrier properties which are necessary for packaging films. Cellulose is the forerunner among renewable polymers for such applications. Hemicelluloses represent a new interesting breed of barrier materials. We have chosen to work with the hemicellulose O-acetyl-galactoglucomannan (AcGGM). The high water solubility of this particular hemicellulose extracted from process waters is both an advantage and a limiting factor. However, through the right modification, the water sensitivity of AcGGM can be regulated.</p><p>This thesis presents four ways to modify AcGGM: (i) benzylation, (ii) plasma surface treatment followed by styrene addition, (iii) vapor-phase (VP) surface grafting with styrene, and (iv) lamination of an unmodified film with a benzylated material. The most important methods of analysis of the films produced include contact angle measurement, dynamic mechanical analysis under moisture scan, and oxygen gas permeability measurement.</p><p>It was found that unmodified AcGGM films have low oxygen permeability at intermediate relative humidity (50 % RH) and good dynamic mechanical properties over a wider humidity range. Films of benzylated material (BnGGM) exhibited a decrease in oxygen permeability at lower humidity but showed better tolerance to higher humidities and indicated better dynamic mechanical behavior than AcGGM films. Lamination proved to be the most promising technique of modification, combining the good gas barrier properties of AcGGM films with the moisture-insensitivity of the BnGGM films.</p>
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Brezeanu, Mihai. "Diamond Schottky barrier diodes." Thesis, University of Cambridge, 2008. https://www.repository.cam.ac.uk/handle/1810/226757.
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Research on wide band gap semiconductors suitable for power electronicdevices has spread rapidly in the last decade. The remarkable results exhibited bysilicon carbide (SiC) Schottky batTier diodes (SBDs), commercially available since2001, showed the potential of wide band gap semiconductors for replacing silicon (Si)in the range of medium to high voltage applications, where high frequency operationis required. With superior physical and electrical properties, diamond became apotential competitor to SiC soon after Element Six reported in 2002 the successfulsynthesis of single crystal plasma deposited diamond with high catTier mobility. This thesis discusses the remarkable properties of diamond and introducesseveral device structures suitable for power electronics. The calculation of severalfigures of merit emphasize the advantages of diamond with respect to silicon andother wide band gap semiconductors and clearly identifies the areas where its impactwould be most significant. Information regarding the first synthesis of diamond,which took place back in 1954, together with data regarding the modern technologicalprocess which leads nowadays to high-quality diamond crystals suitable for electronicdevices, are reviewed. Models regarding the incomplete ionization of atomic dopantsand the variation of catTier mobility with doping level and temperature have beenelaborated and included in numerical simulators. The study introduces the novel diamond M-i-P Schottky diode, a version ofpower Schottky diode which takes advantage of the extremely high intrinsic holemobility. The structure overcomes the drawback induced by the high activationenergies of acceptor dopants in diamond which yield poor hole concentration at roomtemperature. The complex shape of the on-state characteristic exhibited by diamondM-i-P Schottky structures is thoroughly investigated by means of experimentalresults, numerical simulations and theoretical considerations. The fabrication of a ramp oxide termination on a diamond device is for thefirst time reported in this thesis. Both experimental and simulated results show thepotential of this termination structure, previously built on Si and SiC power devices. A comprehensive comparison between the ramp oxide and two other versions of thefield plate termination concept, the single step and the three-step structures, has beenperformed, considering aspects such as electrical performance, occupied area,complexity of technological process and cost. Based on experimental results presented in this study, together withpredictions made via simulations and theoretical models, it is concluded that diamondM-i-P Schottky diodes have the ability to deliver significantly higher performancecompared to that of SiC SBDs if issues such as material defects, Schottky contactformation and measurement of reliable ionization coefficients are carefully addressedin the near future.
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Gandhi, Swapnilkumar J. "Barrier-mediated pulsatile release." Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/1601.
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Solutes are often most efficiently deployed in discrete pulses, for example in the delivery of herbicides or drugs. Manual application of each pulse can be labor-intensive, automated application of each pulse can be capital intensive, and both are often costly and impractical. Barrier-Mediated Pulsatile Release (BMPR) systems offer a materials-based alternative for automated pulsatile drug delivery, without pumps, power supplies, or complex circuitry. While earlier materials-based approaches such as delayed-release microcapsules are limited to two or three pulses due to the independent nature of each pulse’s timing control, BMPR systems link the timing of each pulse to the previous pulse. Each dose of drug is sequestered in its own stimuli-sensitive depot, releasing only upon contact with the stimulant. These depots are stacked with sacrificial barriers in between, each of which block the stimulant for a predetermined time. For instance, layers of soluble drug may be separated by degradable polymer layers. Water, as the stimulant, will erode the polymer layer over a fixed period of time, followed by quick dissolution and release of the underlying drug and the start of degradation for the next polymer layer. This example, however, is quickly limited by irregular polymer erosion, a single stimulant (water), and difficulty in scaling delay times.
The research work presented in this thesis reports the development of a generalized BMPR system which overcomes those limitations. Model drugs (methylene blue and methyl orange) were immobilized in a pH-sensitive polymer [poly(methyl methacrylate-co-dimethylaminoethyl methacrylate)] which released only at low pH. Zinc oxide (ZnO) nanoparticles immobilized in a pH-insensitive matrix [poly(vinyl alcohol)] served as the barrier layer. The time required for acid to penetrate the barrier layer scaled with the ZnO concentration and with the square of the polymer thickness, allowing wide scaling of the delay time with only minor changes to the barrier layer. Harnessing the swelling pressure of the acid-sensitive hydrogel, each barrier/depot bilayer can delaminate upon solute release, directly exposing the next bilayer to the stimulant source. This system has demonstrated tuned release using a citric acid stimulant to produce up to ten pulses of model drug (methylene blue) over various preset timescales. This system has also demonstrated the alternate release of multiple solutes (methylene blue and methyl orange) at regular time intervals up to five pulses from a single BMPR device. For non-delaminating BMPR systems, spent bilayers impede stimulant diffusion to the inner layers and solute diffusion from the inner layers, increasing the delay time and the pulse width. To predict these changes, a computational model was constructed in FORTRAN. This model was extensively explored over a wide range of parameter space to understand the release behavior of various kinds of non-delaminating BMPR systems. The computer model also validates the performances of experimental delaminating BMPR system. This model can be used to guide the physical modeling of BMPR systems. The model also allows to incorporate variety of stimulants other than just acid. BMPR technology introduces efforts to further generalize the delivery strategy by incorporating glucose as a stimulant.
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Kramer, John N. III. "Barrier spit evolution and primary consolidation of backbarrier facies: West Belle Pass Barrier, LA." ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/td/2214.
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West Belle Pass Barrier is a barrier spit that formed during the last delta lobe progradation associated with the Lafourche delta complex. Located on the western flank of the Caminada-Moreau Headland, West Belle Pass Barrier and Raccoon Pass are located downdrift of the Belle Pass jetties. Morphological changes stemming from storms, jetty infrastructure, and an expanding tidal inlet are evaluated using historical shoreline data and imagery. Littoral transport around the jetties combined with inlet growth created a framework wherein sediment is transported through Raccoon Pass and sequestered as a flood-tidal delta. These events aided in the landward migration of West Belle Pass Barrier, which ultimately loaded and consolidated previously unconsolidated facies. A conceptual model illustrating the primary consolidation of backbarrier facies resulting from washover deposits during one storm is presented. The primary consolidation settlement associated with loading near-surface, water-saturated backbarrier facies is substantially larger than current subsidence rates.
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Zhang, Min. "Modelling and fabrication of high performance Schottky barrier SOI-MOSFETs with low effective Schottky barriers." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982694466.
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Germann, Christian. "Pricing Multi Barrier Reverse Convertibles." St. Gallen, 2008. http://www.biblio.unisg.ch/org/biblio/edoc.nsf/wwwDisplayIdentifier/97193445002/$FILE/97193445002.pdf.
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Kjellgren, Henrik. "Barrier properties of greaseproof paper." Licentiate thesis, Karlstad University, Division for Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1411.
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<p>The barrier properties of greaseproof paper are achieved by extensive beating of the fibres. This treatment results in high costs for energy, both as beating energy and drying energy. A full-scale trial has been performed to investigate the role of the pulp with respect to energy demand and the barrier properties of the final papers. The paper made of 100% sulphite pulp with a low degree of beating showed the lowest energy consumption at a given level of barrier properties such as air permeance, grease resistance and water vapour transmission rate.</p><p>The papers produced in the full-scale trial have been used as substrates for coating. Greaseproof paper has a closed surface and should therefore be a good base paper for barrier coatings.</p><p>Chitosan has been used as a barrier coating because of its good oxygen barrier properties. Moreover, chitosan is a renewable material. Coating trials on a bench-scale showed that greaseproof paper can be upgraded to provide a good oxygen barrier. The oxygen barrier could not be achieved on a pilot-scale using the metered size press technique, because of the low coat weight applied.</p><p>The influence of the base paper on the barrier properties of chitosan-coated paper has been investigated. It was found that greaseproof paper is better than a paper with a higher porosity. The coating seemed to stay more on the surface of the greaseproof papers and to form a continuous coating layer with better barrier properties.</p>
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Hoefler, Torsten. "Fast Barrier Synchronization for InfiniBand." Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200600019.
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Barrier Synchronization is crucial for many parallel systems. This talk introduces different synchronization mechanisms and demonstrates new approaches to leverage special hardware properties of InfiniBand to lower the Barrier latency.
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Buraczewska, Izabela. "Skin barrier responses to moisturizers." Doctoral thesis, Uppsala universitet, Institutionen för medicinska vetenskaper, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9300.
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Moisturizers are used in various types of dry skin disorders, but also by people with healthy skin. It is not unusual that use of moisturizers is continued for weeks, months, or even years. A number of moisturizers have been shown to improve the skin barrier function, while others to deteriorate it, but the reason for observed effects remains unknown. Further understanding of the mechanism by which long-term treatment with moisturizers influences the skin barrier would have clinical implications, as barrier-deteriorating creams may enhance penetration of allergens or irritants and predispose to dry skin and eczema, while barrier-improving ones could reduce many problems. The present research combined non-invasive techniques with analyses of skin biopsies, allowing studies of the epidermis at molecular and cellular level. Test moisturizers were examined on healthy human volunteers for their effect on the skin barrier, with regard to such factors as pH, lipid type, and presence of a humectant, as well as complexity of the product. After a 7-week treatment with the moisturizers, changes in transepidermal water loss, skin capacitance, and susceptibility to an irritant indicated a modified skin barrier function. Moreover, the mRNA expression of several genes involved in the assembly, differentiation and desquamation of the stratum corneum, as well as lipid metabolism, was altered in the skin treated with one of the moisturizers, while the other moisturizer induced fewer changes. In conclusion, long-term use of moisturizers may strengthen the barrier function of the skin, but also deteriorate it and induce skin dryness. Moisturizers have also a significant impact on the skin biochemistry, detectable at molecular level. Since the type of influence is determined by the composition of a moisturizer, more careful selection of ingredients could help to design moisturizers generating a desired clinical effect, and to avoid ingredients with a negative impact on the skin.
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Dutheillet, Lamonthezie Yves. "Barrier properties of epoxy coating." Thesis, Brunel University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445939.
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Krezel, Zbigniew Adam, and n/a. "Recycled aggregate concrete acoustic barrier." Swinburne University of Technology, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20060821.154340.
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This document reports on a research project aimed at developing a concrete acoustic barrier
made from Recycled Aggregate (RA) Concrete. The research project was undertaken in
response to the needs expressed by the Victorian concrete recycling industry. The industry,
the scientific community conducting research into relevant disciplines, and the community
at large, represented by Victorian government agencies, are of the opinion that there is a
need to devise a higher value utilisation application for selected concrete recycling
products.
This document outlines the rationale and objectives of the research project which involves
the examination of Recycled Concrete (RC) Aggregate, the design and examination of RA
Concrete, and finally the development of an acoustic barrier made from RA Concrete.
The literature review presented in this report examines aspects of concrete recycling and
concrete technology pertaining to traditional and alternative constituent materials for
concrete production. Firstly, the importance and influence of fine and coarse aggregate on
basic properties of concrete is introduced. Secondly, an account on the use of alternative
materials in concrete technology, especially of coarse recycled aggregates and
supplementary cementitious materials (SCM) is described. Thirdly, some of the physical
and mechanical properties and how the use of RC Aggregate and SCM changes these
properties are discussed. Fourthly, a number of commonly used techniques and neutron
scattering techniques to investigate aggregate and concrete properties are introduced and
discussed. Fifthly, the porosity of aggregate and concrete including durability are
specifically discussed and testing methods are reasoned. The literature review also
discusses the use of no-fines concrete; its physical, mechanical and acoustic properties.
Finally it presents an account of the use of concrete in transportation traffic noise
attenuation devices.
This document continues with an outline of a methodology that was adopted in this
research project. It outlines experimental work aimed at examining the properties of RC Aggregate which amongst other properties includes porosity, particle size distribution,
water absorption, shape and density. It continues examining RA Concrete properties and
includes, among other properties, compressive strength, porosity and durability as well as
sound absorption of acoustic barrier. The methodology introduces standard and purposely
modified test procedures used in the examination of aggregates, concrete and acoustic
barrier. An account of various research techniques is presented, spanning from simple
visual observations to more sophisticated neutron scattering techniques. The summary of
test procedures follows a description of test specimen composition and their sizes, and a
suite of tested specimens. It also introduces statistical methods used to analyse test results.
After a detailed description of the aggregate, concrete and RA Concrete acoustic barrier,
the document outlines a summary of data generated through the experimental program of
this research project. The data on fine aggregate, on selected 14/10mm coarse RC
Aggregate, on concrete made from natural and recycled aggregate and on acoustic barrier
are presented and discussed. Test results of various physical, mechanical and acoustic
properties of aggregate, concrete and barrier are reported, analysed and discussed. The data
from observations, visual assessment and scientific experimentation of specific properties
are then crossed analysed in a search for relationships between properties of fine and coarse
aggregates and properties of concrete made from such aggregates. A cross analysis of data
on ?less-fines? RA Concrete and on the acoustic performance of barrier is examined, and
the relationship between the volume of interconnected voids in a porous part of ?less-fines?
concrete, and the sound absorption of acoustic barrier is discussed and reported.
The document then presents a synthesis of the literature review results, project aims
adopted within the experimental program and test results in the three main areas of this
research project. These areas include recycled concrete aggregate, recycled aggregate
concrete and acoustic barrier made from RA Concrete.
Finally, conclusions reached through the course of this investigation are summarised and
recommendations are proposed in relation to the RA Concrete acoustic barrier. The main
conclusion is that selected RC Aggregate can be used in the production of concrete of a compressive strength of 25MPa, if the moisture content and water absorption in the
aggregate are closely monitored, and the foreign material content is kept below 1.5%. The
author concludes that acoustic barrier made from selected RC Aggregate has unique sound
absorption characteristics that can easily be tunable by a selection of appropriate aggregate
and by specific concrete mix designs. Recommendations for further research are also
proposed.
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Krezel, Zbigniew Adam. "Recycled aggregate concrete acoustic barrier." Australasian Digital Theses Program, 2006. http://adt.lib.swin.edu.au/public/adt-VSWT20060821.154340.
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Thesis (PhD) - Swinburne University of Technology, 2006.<br>Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Civil Engineering, Swinburne University of Technology - 2006. Typescript. Includes bibliographical references.
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Rees, P. K. "Two terminal triangular barrier devices." Thesis, Swansea University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638641.
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The detailed theory of two terminal triangular barrier devices including minority carrier effects is investigated. Most of the available theories describing the operation of the traingular barrier diode are analysed and compared with each other. Novel experimental d.c. results for triangular barrier diodes are presented for structures with different asymmetries and zero bias barrier heights. Six different designs for triangular barrier switches are all shown to display switching action. The switching threshold is shown to be a sensitive function of the area doping concentration of the p-plane and of the asymmetry of the zero-bias potential barrier. The measured switching thresholds are in broad agreement with theoretical predictions from the minority models discussed and a substantial database is provided for future work. The triangular barrier switch is optically sensitive and may be switched by a pure electrical signal, pure optical signal, or some combination of the two. The triangular barrier switch is shown to be a fast regenerative switching element with a 10-90% turn-on time of < 300 ps. The nature of the dominant electron current conduction mechanism in a triangular barrier switch is shown to vary with temperature. The three regions of operation for the traingular barrier switch at different temperatures i.e. field emission, thermionic-field emission and thermionic emission, are defined for a given structure and verified experimentally. There is good agreement between theoretical and experimental results. The applications of the triangular barrier diode and the triangular barrier switch are discussed. One application of the triangular barrier switch is demonstrated experimentally: it is used as a variable width pulse generator with well defined rise and fall times determined by the turn-on response of the triangular barrier switch.
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Zhou, Xin Hua. "Characterisation of drug absorption barrier." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335622.
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Miller, Jeffrey Rush. "Barrier and Threshold in Architecture." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/35007.
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This thesis explores the role of barrier and threshold as a form of differentiation between objects and situations. Building elements such as façade, structure, and space become the means by which to distinguish between separate parts, functions, and experiences. Sited in downtown Washington D.C. the proposed office building becomes the permeable barrier between street and lawn. Within the building there is contrasting differentiation between service space and occupiable office space through the role of different building parts that make up an office building.<br>Master of Architecture
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Polleres, Axel, Jürgen Umbrich, Kathrin Figl, and Martin Beno. "Perception of Key Barriers in Using and Publishing Open Data." JeDEM, 2017. http://epub.wu.ac.at/6140/1/Polleres_etal_2017_JEDEM_Perception%2Dof%2DKey.pdf.
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There is a growing body of literature recognizing the benefits of Open Data. However, many potential data providers are unwilling to publish their data and at the same time, data users are often faced with difficulties when attempting to use Open Data in practice. Despite various barriers in using and publishing Open Data still being present, studies which systematically collect and assess these barriers are rare. Based on this observation we present a review on prior literature on barriers and the results of an empirical study aimed at assessing both the users' and publishers' views on obstacles regarding Open Data adoption. We collected data with an online survey in Austria and internationally. Using a sample of 183 participants, we draw conclusions about the relative importance of the barriers reported in the literature. In comparison to a previous conference paper presented at the conference for E-Democracy and Open Government, this article includes new additional data from participants outside Austria, reports new analyses, and substantially extends the discussion of results and of possible strategies for the mitigation of Open Data barriers.
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Podjaski, Cornelia. "Netrins enhance blood-brain barrier function and regulate immune responses at the blood-brain barrier." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116977.
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During development, netrin guidance cues control cell motility and cell adhesion. Cell-adhesion between endothelial cells at the blood-brain barrier makes the endothelium impermeable to blood-derivatives and immune cells. To establish and maintain this barrier during development, and adulthood, and as well as during disease, brain endothelial cells must develop and sustain these strong adhesive contacts, through expression of tight junction molecules. However, we do not know whether netrins support inter-endothelial cell adhesion at the blood-brain barrier. Given this, we hypothesize that netrin tightens the blood-brain barrier during development, adulthood, and protects it during disease. Methods: To test this, we used both human adult primary brain-derived endothelial cells and newborn netrin-1 knockout mice and evaluated netrin's effect on inter-endothelial cell adhesion and barrier permeability. We also assessed netrins' therapeutic potential to maintain the barrier and limit immune cell infiltration into the central nervous system (CNS) during experimental autoimmune encephalomyelitis (EAE). Results: Our results demonstrate that brain endothelial cells express netrins where they function in three ways. They help to form a tighter blood-brain barrier during development. They also maintain and protect the adult barrier by increasing the expression of endothelial junction molecules, thus promoting inter-endothelial adhesion and reducing protein leakage across the barrier. Netrins also reduce blood-brain barrier breakdown and diminish initial myeloid cell infiltration into the brain and spinal cord during EAE, which delays disease onset and ameliorates disease severity. However, during the chronic phase of EAE, netrin-1 treated mice have higher numbers and more activated T cells in their CNS and exhibit an ataxic gait and limb spasticity. Discussion: We conclude that netrins enhance BBB stability, but have dual functions on immune responses during neuroinflammatory disease. These findings favour the hypothesis that if netrin function was to be manipulated as a therapeutic, early short-term approaches would likely be the most effective.<br>Au cours du développement, les molécules de la famille des nétrines contribuent à la morphologénèse des organes en contrôlant la motilité et l'adhérence cellulaire. L'adhérence cellulaire entre les cellules endothéliales est une caractéristique importante de la barrière hémato-encéphalique (BHE), ce qui rend l'endothélium imperméable aux molécules sanguines et aux cellules immunitaires. Pour établir et maintenir cette barrière au cours du développement, à l'âge adulte et au cours de la maladie, les cellules endothéliales du cerveau doivent développer et maintenir ces contacts adhésifs en exprimant des molécules de jonction serrées. Cependant, nous ne savons pas si les molécules de la famille des nétrines influencent l'adhérence cellulaire inter-endothéliale de la BHE. Nous avons donc émis l'hypothèse que les nétrines resserrent la BHE au cours du développement, à l'âge adulte, et la protège au cours de la maladie.Méthodes: Pour valider notre hypothèse, nous avons utilisé des cellules endothéliales primaires dérivées des cerveaux humains adultes ou des cerveaux de souris nouveau-nés déficientes en nétrine-1 et évalué l'effet de la nétrine sur l'adhésion cellulaire endothéliale et inter-perméabilité de la barrière. Nous avons également évalué le potentiel thérapeutique des nétrines a restaurer la barrière et l'infiltration de cellules immunitaires limite dans le système nerveux central (SNC) pendant encéphalomyélite allergique expérimentale, un modèle animal de sclérose en plaques. Résultats: Nos résultats démontrent que les nétrines sont exprimées par les cellules endothéliales du cerveau, exprimes nétrines. Au cours du développement les nétrines aident à assurer l'étanchéité de la BHE. Chez les adultes, ils maintiennent et protègent la barrière adulte en augmentant l'expression des molécules de jonctions serrées, favorisant ainsi l'adhérence inter-endothéliale et diminuant les fuites de protéines à travers la BHE. Dans la pathologie de l'EAE, le rôle des nétrins diffère en fonction de la phase de la maladie. Au cours de la phase aigue, les nétrines atténuent la perte de l'intégrité de la BHE et diminuent l'infiltration des cellules myéloïdes dans le SNC. Ceci retarde l'apparition de la maladie et réduit sa sévérité. Au cours de la phase chronique de l'EAE, les souris traitées avec netrin-1 ont un plus grand nombre des cellules T activées dans leurs SNC et présentent une démarche ataxique ainsi qu'une spasticité des membres. Discussion: Nous concluons que les nétrins améliorent la stabilité de la BHE. Ces résultats suggèrent que les nétrines peuvent être envisagée comme agent thérapeutique dans les maladies neuroinflammatoire. Dans ce cas une approche précoce et à court terme serait probablement plus efficace.
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Du, Plessis Sonette. "The influence of different types of barrier creams on skin barrier function / Sonette du Plessis." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8684.
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Aims and objectives: The research aims and objectives of this study were: Firstly to determine the positive effects and possible disadvantages of three types of barrier creams on skin barrier function by determining skin barrier function by measuring stratum corneum hydration transepidermal water loss (TEWL) and skin surface pH. Secondly to compare different racial skin types (African skin to Caucasian skin) by determining the effects of barrier cream on skin barrier function. Finally to compare the effect of the three different barrier creams on four different anatomical areas.
Methods: Thirty eight non-smoking male test subjects took part in this study where three different types of barrier creams were tested on their arms and hands in a controlled laboratory environment. The thirty eight test subjects consisted of nineteen African and nineteen Caucasian test subjects. Three parameters were measured namely TEWL, stratum corneum hydration and pH condition of the skin. TEWL was measured using a Vapometer (Delfin Technology Ltd. Finland). The Multi probe Adapter system (MPA) (Courage and Khazaka, Germany) was used with a temperature and humidity sensor and with the following probes all from Courage and Khazaka, Germany: a Corneometer measuring skin hydration and a pH-Meter measuring skin surface pH. The measurements were repeated on each of the four sampling areas (forearm, wrist, back of hand and palm) with a reasonable time interval between each measurement. After the baseline measurement the barrier cream was applied by the researcher on the test subjects’ dominant arm. The long term effects were determined after the baseline measurement in intervals of 2 hours. Directly after each measurement the barrier cream was reapplied.
Results: Gloves In A Bottle™ increased stratum corneum hydration, had no effect on TEWL and increased skin surface pH, whereas Reinol™ increased stratum corneum hydration and decreased TEWL and had no effect on pH values. Travabon™ decreased stratum corneum hydration and TEWL and had no effect on skin surface pH. The results indicated that there were significant differences between Caucasian and African test subjects with the use of barrier creams, because of the baseline differences and the reaction to barrier creams showed different results. There were also statistically significant differences in the four different anatomical areas where the barrier creams were applied.
Conclusion: Barrier creams are beneficial in the workplace, although it should be taken into consideration that different ethnicities react differently to barrier creams under different workplace situations and therefore this should be taken into account when selecting a barrier cream.<br>Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013
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Zhu, Chunni. "The Blood-brain barrier in normal and pathological conditions." Title page, abstract and contents only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phz637.pdf.
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Bibliography: leaves 318-367. Examines the blood-brain barrier in normal and pathological conditions induced by intravascular and extravascular insults. Intravascular insults were induced by administration of Clostridium perfringens prototoxin; extravascular insults were induced by an impact acceleration model for closed head injury to induce traumatic brain injury. Also examines the integrity of the blood-brain barrier ultrastructurally and by its ability to exclude endogenous and exogenous tracers. Also studies the expression of 2 blood-brain barrier specific proteins, endothelial barrier antigen (EBA) and glucose transporter 1 (GLUT1)
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Ferreira, Guilherme Neves. "Bioaerossóis na indústria farmacêutica." Universidade do Estado do Rio de Janeiro, 2009. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2766.
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Este estudo teve como finalidade, testar uma barreira contra a contaminação microbiológica em placas de contato, utilizadas em monitoramento de salas limpas para fabricação de produtos farmacêuticos estéreis. Durante o ano de 2007, foram realizados testes de contato com a utilização da mencionada barreira, e os resultados foram comparados com dados dos anos de, 2004, 2005 e 2006, quando a barreira não foi utilizada. Os ambientes utilizados para os testes foram duas salas limpas de uma planta farmacêutica localizada no Rio de Janeiro.
Nos mencionados ambientes é necessário o uso de uma vestimenta especial, de forma a evitar que partículas do corpo dos operadores, bactérias e fungos, migrem para a superfície externa do uniforme e coloquem em risco a esterilidade dos produtos. Sendo assim, foi proposta a colocação de uma camiseta diretamente sobre a pele do operador durante todo o ano de 2007 de forma a evitar ou reduzir a possibilidade de migração dessas partículas; e os resultados foram comparados com os anos de 2004, 2005 e 2006, quando a camiseta não foi usada. Os testes demonstraram que houve uma redução de cerca de 50% na ocorrência de placas contaminadas. Com relação ao número total de colônias formadas, a redução foi de 75% na comparação com os anos de 2004 e 2005 e de 50% com relação ao ano de 2006<br>This study had as objective to test a barrier against microbiological contamination in contact plates that are used in sterile pharmaceutical products clean rooms monitoring. During 2007 the tests were performed and compared with data from, 2004, 2005 and 2006, when the mentioned barrier was not used. The test environments were two clean rooms from a pharmaceutical plant located at Rio de Janeiro. In the mentioned environments the use of special garments is necessary for avoiding that particles from operators bodies, bacteria and most remain in contact with the room environment, adding risk to the sterilized products. So, it was proposed the use of undershirt between the garment and the operator skin for reducing the contact plates contamination during the regular rooms monitoring. This undershirt was used during 2007 and the results were compared with the samples of 2004, 2005 and 2006 when the undershirt was not used. The results demonstrated that it was obtained a reduction of about 50% in relation to contaminated plates. In relation to the total number of colonies the reduction was 75% in comparison with 2004 and 2005, and 50% in comparison with 2006
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Kuhr, Marlena, Dilbar Aibibu, and Chokri Cherif. "Targeted partial finishing of barrier textiles with microparticles, and their effects on barrier properties and comfort." Sage, 2016. https://tud.qucosa.de/id/qucosa%3A35613.
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Woven barrier fabrics for filtration and operating room textiles feature permeable pore channels between yarn interlocking points (mesopores), which create an increased risk of penetration by contaminated fluids and particles. These pore channels can be reduced in size by high-density weaving. This, however, results in deteriorated drapability and performance characteristics. To meet the requirements made on the barrier effect without impairing the physiological properties of the textile, fluid-tight and particle-tight woven fabrics with adjustable porosity are being developed. This research aim could be realized by the targeted and partial application of microparticles into the mesopores. There, they form a meshed structure in the pores, whose size is thus reduced without them being entirely obstructed. The simultaneous retention of the micropores (pores between the individual filaments) in the woven fabric guarantees preservation of the physiological characteristics of the textile. The efficiency of the finishing was examined by an extensive physiological and physical characterization of the woven fabrics before and after particle application. Regarding the test method used to monitor the barrier effect and the channel paths, a test device was modified to simulate the demands of later, practical use.
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Moen, Endre Fylling. "Maintenance and barriers : Principles for barrier management in the petroleum industry will be more and more important and It is fundamental to understand the maintenance function in the barrier management." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for produksjons- og kvalitetsteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26133.
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SummaryThis thesis' sets out to analyse and present the purpose and meaning of safety, maintenance functions and management, maintenance indicators, barrier management and the importance and dependency between those. In addition, this is done in relation to the petroleum industry in Norway, and in collaboration with DNV GL, to develop an improved concept of barrier management. The analyses, discussions and conclusions are done at the basis of earlier accident reports and relevant literature.Safety is the overall process of ensuring a safe environment for every included and associated object. A function that is designed and developed to maintain safety is dependent on frequent maintenance in order to maintain its functionality and capability.One of the four top priorities in the Petroleum Safety Authority Norway's future development program is the improved integration of barriers and barrier management. Barriers are often defined as an obstacle, or a function, to prevent any form of hazardous energy to penetrate at an unwanted area, process or situation. The present situation in the industry indicates deviations in the common understanding and usage of barriers, and there are several areas of potential improvement.In barrier management and the phase of monitoring and improving existing solutions, maintenance has a significant role of making the barriers more relevant, efficient and resilient due to changes, time dependent wear and modifications in the systems. To utilize and control the barriers at the highest level possible, the need for an organised management is required. This includes maintenance, which is an essential process in barrier management of proactively ensure the barriers' continuous improvement and resilience.Maintenance indicators in accordance to barriers could be integrated in barrier management with the purpose of revealing weaknesses and areas of improvement. Backlogging is a maintenance indicator, which reveals if planned and preventive maintenance activities are performed in accordance with the scheduled plan. Backlogging is often measured in days or weeks. Another maintenance indicator is number of errors revealed during maintenance and testing. This indicator measures the ratio of errors in a barrier, after performing a test or maintenance operation. A barrier function often consists of several barrier elements, in which the barrier elements could be both technical, operational and organisational. Thus, maintenance functions and indicators are necessary to maintain and improve the elements. It is important to note, however, that maintenance is not regarded as a direct barrier element in itself.This survey has developed a concept suggestion in cooperation and relation to DNV GL, with the focus at future barrier management guidelines. The emphasis has been on implementing maintenance activities and potential maintenance procedures in the barrier management within areas where earlier/present weaknesses are identified. More specific, a DNV GL concept of internal cooperation and exchange of experience is presented.
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Vander, Wielen Lorraine C. "Dielectric barrier discharge-initiated fiber modification." Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/ipstetd-1054/.
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Vander, Wielen Lorraine C. "Dielectric barrier discharge-initiated fiber modification." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7091.
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Bubik, Martin. "Endothelial barrier protection by natural compounds." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-112945.
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Göritzer, Andreas. "Thin Capitalization Rule vs Interest Barrier." WU Vienna University of Economics and Business, 2010. http://epub.wu.ac.at/2944/1/workingpaper41_goeritzer_online.pdf.
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To be able to do business, companies have to be equipped with capital by their shareholders.
Usually, this capital is granted to them as equity. Nevertheless, it is also reasonable for shareholders to provide debt to the company. In any case, companies have to onsider the differences in taxation regarding equity and debt financing. That is why for internationally operating roups of companies the differing legal frameworks between countries are crucial factors for making decisions in corporate financing (Obser 2005: 1ff), especially because interest expenditure due to debt financing is usually tax-deductible in almost every country and thus considerably reduces a company's tax base (Jacobs 2007, 909). Hence, internationally operating companies should consider the various differing corporate tax rates between countries in their financing strategies in order to minimize their total tax base. (author's abstract)<br>Series: Discussion Papers SFB International Tax Coordination
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Curry, Nicholas. "Design of Thermal Barrier Coating Systems." Doctoral thesis, Högskolan Väst, Institutionen för ingenjörsvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-5931.
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Thermal barrier coatings (TBC’s) are used to provide both thermal insulation and oxidation protection to high temperature components within gas turbines. The development of turbines for power generation and aviation has led to designs where the operation conditions exceed the upper limits of most conventional engineering materials. As a result there has been a drive to improve thermal barrier coatings to allow the turbine to operate at higher temperatures for longer. The focus of this thesis has been to design thermal barrier coatings with lower conductivity and longer lifetime than those coatings used in industry today. The work has been divided between the development of new generation air plasma spray (APS) TBC coatings for industrial gas turbines and the development of suspension plasma spray (SPS) TBC systems. The route taken to achieve these goals with APS TBC’s has been twofold. Firstly an alternative stabiliser has been chosen for the zirconium oxide system in the form of dysprosia. Secondly, control of the powder morphology and spray parameters has been used to generate coating microstructures with favourable levels of porosity. In terms of development of SPS TBC systems, these coatings are relatively new with many of the critical coating parameters not yet known. The focus of the work has therefore been to characterise their lifetime and thermal properties when produced in a complete TBC system. Results demonstrate that dysprosia as an alternative stabiliser gives a reduction in thermal conductivity. While small at room temperature and in the as produced state; the influence becomes more pronounced at high temperatures and with longer thermal exposure time. The trade-off for this lowered thermal conductivity may be in the loss of high temperature stability. Overall, the greatest sustained influence on thermal conductivity has been from creating coatings with high levelsof porosity. In relation to lifetime, double the thermo-cyclic fatigue (TCF) life relative to the industrial standard was achieved using a coating with engineered porosity. Introducing a polymer to the spray powder helps to generate large globular pores within the coating together with a large number of delaminations. Such a structure was shown to be highly resistant to TCF testing. SPS TBC’s were shown to have much greater performance relative to their APS counterparts in thermal shock life, TCF life and thermal conductivity. Columnar SPS coatings are a prospective alternative for strain tolerant coatings in gas turbine engines.
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Jones, Robert Edward. "Bondcoat developments for thermal barrier coatings." Thesis, Sheffield Hallam University, 1999. http://shura.shu.ac.uk/3137/.
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The prime design considerations for modern nickel based superalloys for use in aero gas-turbine engines, are those of mechanical performance, namely good resistance to creep and fatigue with good toughness and microstructural phase stability. Design of the current generation of superalloys has attained these properties at the expense of environmental resistance. This design philosophy has lead to the widespread use of surface coatings technology to protect hot-section componentry from the harsh operating environment. The ongoing drive towards higher operating temperatures has lead to an interest, over the last few years, in thermal barrier coatings (TBCs). TBCs are duplex coating systems consisting of a thin, insulating, ceramic layer over a metallic bondcoat. The bondcoat provides both environmental protection and the necessary adhesive interface to maintain the adherence of the ceramic during the rigours of operation. Central to the performance of a TBC system is the integrity and adherence of the alumina scale promoted by the bondcoat. This study aimed to design and optimise a novel bondcoat system that was capable of out-performing the current generation of bondcoats and progress the resultant coating into a production ready status. This was achieved by comparing the performance of a range of bondcoats of both novel and standard compositions, using the modified scratch test in conjunction with hot isothermal and cyclic furnace tests. The down selected system was then analysed using a range of techniques including optical and electron microscopy, XRD, WDS and SIMS in order to understand the failure mechanisms. The results of the testing programme lead to bondcoat chemistry changes and processing improvements that enabled better performance to be achieved. The bondcoat was optimised and taken to a production standard by using the Taguchi Method of fractional factorial experimental design. The resultant coating system offered a higher TBC/bondcoat interface temperature capability and extended the life of the system at more moderate temperatures, beyond that offered by systems currently available. The coating system has subsequently been run as a bondcoat for EB-PVD TBCs and has successfully completed the duty cycles on a number of development and test engines.
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Parks, Rowan Wesley. "Gut barrier function in obstructive jaundice." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361292.
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McDonnell, Paul. "Resonant tunnelling across double barrier structures." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285640.
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Henry, Brian T. "The barrier function of gastrointestinal mucus." Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334550.
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Hallam, Jonathan. "Barrier trees for studying search landscapes." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438685.
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Morgan, David Cenydd. "Recycling multi-layer barrier packaging waste." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608609.
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Huang, Guangming. "Dielectric barrier discharges for ozone generation." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27626.
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Non-thermal plasma discharges, particularly dielectric barrier discharges (DBDs), are the most common method of ozone generation. The aim of this research was to optimize the micro-discharges in DBDs, to improve ozone generation efficiency. The electrical characteristics of DBDs were researched, and the effects of the physical and electrical parameters of DBDs on ozone generation were investigated. Four DBD based ozone reactors, including plate configuration and cylindrical configuration, were designed and developed. Three major energization modes, including transient (40 ms) AC power supply, continuous AC power supply and pulsed power supply, were used for the investigation of ozone generation performance. Under transient AC energisation in oxygen, it was found that the ozone generation efficiency at 2 bar absolute was 217 g/kWh, increased by 31% compared with that at 1 bar absolute. The ozone generation efficiency was found to increase with decreasing E/N in the range from 126 Td to 185 Td. Under continuous AC energisation, the ozone concentration was found to increase as the gas flow rate decreased (from 1 L/min to 0.4 L/min) or applied voltage was increased (from 3.5 kV to 6 kV). Under optimized conditions, the highest ozone concentration obtained was 271 g/Nm3, which is promising in comparison with previously-published data. The ozone generation efficiency was found to reduce as the ozone concentration increased above 30 g/Nm3. Furthermore, it was found that the AC energization frequency had no obvious effect on the behaviour of micro-discharges, or on the ozone generation efficiency. Pulsed DBDs for ozone generation was found to be less efficient than continuous AC energisation, for the conditions investigated herein. This research has achieved the desired combination of high ozone generation efficiency at high ozone concentration (>150 g/Nm3), based on DBDs The curve of ozone generation efficiency versus ozone concentration achieved shows more efficient performance than that in the literature: at the typical industrial ozone concentration of 150 g/Nm3 for waste water treatment, the ozone generation efficiency in this work was ~8.2 kWh/kg, ~20% higher than that in the literature.
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Chern, Kevin Tsun-Jen. "GaInN/GaN Schottky Barrier Solar Cells." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/52899.
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GaInN has the potential to revolutionize the solar cell industry, enabling higher efficiency solar cells with its wide bandgap range spanning the entire solar spectrum. However, material quality issues stemming from the large lattice mismatch between its binary endpoints and questionable range of p-type doping has thus far prevented realization of high efficiency solar cells. Nonetheless, amorphous and multi-crystalline forms of GaInN have been theorized to exhibit a defect-free bandgap, enabling GaInN alloys at any indium composition to be realized. But the range of possible p-type doping has not yet been determined and no device quality material has been demonstrated thus far. Nonetheless, a Schottky barrier design (to bypass the p-type doping issue) on single-crystal GaInN can be used to provide some insight into the future of amorphous and micro-crystalline GaInN Schottky barrier solar cells. Through demonstration of a functional single crystalline GaInN Schottky barrier solar cell and comparison of the results to the best published reports for more conventional p-i-n GaInN solar cells, this work aims to establish the feasibility of amorphous and multi-crystalline GaInN solar cells.<br>Ph. D.
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Wännman, Caroline. "Erosion Behaviour of Thermal Barrier Coatings." Thesis, Linköpings universitet, Konstruktionsmaterial, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-176646.
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Thermal barrier coatings (TBCs) are advanced material systems used in the hot sections of gas turbines. The TBCs are designed to provide insulation against hot gases by a ceramic top coat and to provide oxidation and corrosion resistance by a metallic bond coat. As the operating environment is harsh and complex, the TBC often requires stricter material properties. Failure of TBCs can limit the longevity of the turbine severely. In this study, failure caused by erosion has been the main focus. The erosion behaviour of TBCs processed by atmospheric plasma spay (APS), electron beam physical vapour deposition (EB-PVD), and plasma spray physical vapour deposition (PS-PVD) has been studied by an experimental investigation and a literature study. The erosion performance of different TBCs was studied by conducting erosion tests under 90° and 15° alumina particle impact (50 μm) and measuring the weight loss and thickness loss of the ceramic top coat. Variables affecting the erosion behaviour were studied by means of scanning electron microscopy (SEM), investigating the microstructure, the erosion damage, porosity content, and column density. Hardness tests were also conducted to investigate a potential correlation between hardness and erosion performance. It was evident that the 8YSZ top coat processed by EB-PVD had higher erosion resistance than APS, which in turn had higher erosion resistance than PS-PVD. Their microstructures are significantly different, resulting in different erosion failure mechanisms. APS TBCs have a splat-on-splat lamellar microstructure, and the failure mechanismsare ploughing of furrows, splat boundary failure, and tunneling via pores. In contrast, EB-PVD TBCs have columnar microstructure and fail by near-surface cracking. The investigated PS-PVD TBC had a feathery columnar microstructure, containing many large grain boundaries and flaws, making grain boundary failure the governing mechanism. The APS and EB-PVD TBCs impacted at a 90° angle had significantly higher erosion rates than those eroded at 15°, which also was reported in literature. However, the opposite was observed for the PS-PVD TBCs. The level of porosity and hardness of the TBC top coat was found to affect the erosion rate, even though no evident correlations could be observed in this study. No factor alone was found to dictate the erosion behaviour of the investigated TBCs. Based on the literature study and findings in the experimental study, a TBC with good erosion performance has, in general, low porosity, few defects, high hardness and high fracture toughness. Specifically for APS TBCs, good splat bonding is favourable and for EB-PVD and PS-PVD it recommended to have high column density, columns orthogonal to the substrate, and low gap width between the columns.
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Irvine, Alan David. "The epidermal barrier in atopic disease." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.706985.
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The prevalence of allergic diseases, including atopic dermatitis (AD; also known as atopic eczema), food allergy, hay fever, asthma, atopic eye disease and eosinophilic eosophagitis has increased dramatically in the developed world and in urbanised parts of the developing world over the past several decades. Atopic dermatitis is the most common chronic inflammatory disease of children, affecting 15-20% of children in the US and Europe. In many cases, infantile AD is associated with significant allergies to common foods such as peanut, hen’s egg and cow’s milk. Atopic dermatitis is followed in approximately 50% of cases by development of asthma and in 70%, hay fever in later childhood. The clustering of these conditions that often occurs in sequence has been termed the ‘atopic march’. The basis for the remarkable increase in the prevalence of these diseases is not well understood. For most of the latter half of the 20th Century the pathogenesis of atopic dermatitis was assumed to be primarily due to immune dysregulation. In the first decade of the 21st century, however, several lines of evidence emerged that placed the epithelial barrier as a central player in the pathogenesis of AD and of atopic disease in general. Several key discoveries that contributed to this change in understanding are included in the collection of publications presented for this DSc submission. The publications can be broadly grouped into studies on single gene disorders, their relevance to complex disease, subphenotyping of complex disease, mechanistic work and finally, some early translational approaches.
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Laudier, Natalie A. "Wave overtopping of a barrier beach." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FLaudier.pdf.
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Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, September 2009.<br>Thesis Advisor(s): MacMahan, Jamie. "September 2009." Description based on title screen as viewed on 5 November 2009. Author(s) subject terms: Overtopping, run-up, barrier, natural beach, Carmel River Beach Includes bibliographical references (p. 41-44). Also available in print.
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Roberts, Angus. "Clinical information extraction : lowering the barrier." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/3254/.
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Electronic Patient Records have opened up the possibility of re-using the data collected for clinical practice, to support both clinical practice itself, and clinical research. In order to achieve this re-use, we have to address the issue that most Electronic Patient Records make heavy use of narrative text. This thesis reports an approach to automatically extract clinically significant information from the textual component of the medical record, in order to support re-use of that record. The cost of developing such information extraction systems is currently seen to be a barrier to their deployment. We explore ways of lowering this barrier, through the separation of the linguistic, medical and engineering knowledge and skills required for development. We describe a rigorous methodology for the construction of a corpus of clinical texts semantically annotated by medical experts, and its use to automatically train a supervised machine learning-based information extraction system. We explore the re-use of existing medical knowledge in the form of terminologies, and present a way in which these terminologies can be coupled with supervised machine learning for information extraction. Finally, we consider the extent to which pre-existing software components can be used to construct a clinical IE system, and build a system that is capable of extracting clinical concepts, their properties, and the relationships between them. The resulting system shows that it is possible to achieve separation of linguistic, medical and engineering knowledge in clinical information extraction. We find that existing software frameworks are capable of some aspects of information extraction with little additional engineering work, but that they are not mature enough for the construction of a full system by the non-expert. We also find that a new cost is introduced in separating domain and linguistic knowledge, that of manual annotation by domain experts.
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Costa, Maria Carolina Simões. "Internship and Monograph Reports entitled “Nanotechnologies to Overcome the Blood Brain Barrier and the Blood Retinal Barrier”." Master's thesis, 2021. http://hdl.handle.net/10316/99159.
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Relatório de Estágio do Mestrado Integrado em Ciências Farmacêuticas apresentado à Faculdade de Farmácia<br>O aumento da prevalência de doenças relacionadas com o envelhecimento da população, tal como doenças neurodegenerativas e doenças degenerativas da retina levou a um crescente interesse em otimizar o tratamento destas.No entanto, a entrega de fármacos no cérebro e no olho não é assim tão linear, devido à presença de barreiras que protegem estes órgãos.Tornou-se, portanto, necessário desenvolver estratégias para a formulação de fármacos eficazes no tratamento destas doenças.A utilização de nanotecnologia para o tratamento de doenças tem crescido nos últimos anos. O uso de nanopartículas tem provado um enorme potencial em melhorar a farmacocinética do fármaco e a sua veiculação.Devido às suas características, o uso de nanopartículas para o tratamento de doenças do sistema nervoso central e da retina tem sido imensamente estudado. Esta revisão pretende abordar as dificuldades em ultrapassar as barreiras que protegem o cérebro e o olho, bem como os vários estudos de desenvolvimento de nanopartículas com o objetivo de formular estratégias terapêuticas para o tratamento de doenças neurodegenerativas e doenças degenerativas da retina. Ao longo desta revisão é feita menção a varios estudos publicados em que são abordadas diferentes nanopartículas com potencial para atuar nos alvos destas doenças. No presente trabalho encontra-se os relatórios referentes aos estágios realizados em farmácia comunitária e indústria farmacêutica, onde é feita uma abordagem SWOT (Strengths, Weaknesses, Opportunities and Threats) para discutir os aspetos mais pertinentes dos estágios.<br>The increasing prevalence of diseases related to an aging population, such as neurodegenerative diseases and retinal degenerative diseases, has led to a growing interest in optimizing their treatment.However, drug delivery to the brain and eye is not that easy, due to the presence of barriers that protect these organs. Therefore, it became necessary to develop strategies for the formulation of effective drugs in the treatment of these diseases.The use of nanotechnology to treat diseases has grown interest in recent years. The use of nanoparticles has proven an enormous potential in improving drug pharmacokinetics and its delivery.Due to their characteristics, the use of nanoparticles for the treatment of diseases of the central nervous system and the retina has been extensively studied.This review intends to address the difficulties in overcoming the barriers that protect the brain and the eye, as well as the various studies on the development of nanoparticles with the aim to formulate therapeutic strategies for the treatment of neurodegenerative diseases and retinal degenerative diseases.Throughout this review, mention is made of several published studies in which different nanoparticles with potential to act on the targets of these diseases are addressed.In this work, the reports refering to the internships in communitary pharmacy and pharmaceutical industry are discussed, to evaluate the relevant aspects refering to the internships is used a SWOT (Strengths, Weaknesses, Opportunities and Threats) approach.
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Costa, Maria Carolina Simões. "Internship and Monograph Reports entitled “Nanotechnologies to Overcome the Blood Brain Barrier and the Blood Retinal Barrier”." Master's thesis, 2021. http://hdl.handle.net/10316/99176.
Full textAbstract:
Relatório de Estágio do Mestrado Integrado em Ciências Farmacêuticas apresentado à Faculdade de Farmácia<br>O aumento da prevalência de doenças relacionadas com o envelhecimento da população, tal como doenças neurodegenerativas e doenças degenerativas da retina levou a um crescente interesse em otimizar o tratamento destas.No entanto, a entrega de fármacos no cérebro e no olho não é assim tão linear, devido à presença de barreiras que protegem estes órgãos.Tornou-se, portanto, necessário desenvolver estratégias para a formulação de fármacos eficazes no tratamento destas doenças.A utilização de nanotecnologia para o tratamento de doenças tem crescido nos últimos anos. O uso de nanopartículas tem provado um enorme potencial em melhorar a farmacocinética do fármaco e a sua veiculação.Devido às suas características, o uso de nanopartículas para o tratamento de doenças do sistema nervoso central e da retina tem sido imensamente estudado. Esta revisão pretende abordar as dificuldades em ultrapassar as barreiras que protegem o cérebro e o olho, bem como os vários estudos de desenvolvimento de nanopartículas com o objetivo de formular estratégias terapêuticas para o tratamento de doenças neurodegenerativas e doenças degenerativas da retina. Ao longo desta revisão é feita menção a varios estudos publicados em que são abordadas diferentes nanopartículas com potencial para atuar nos alvos destas doenças. No presente trabalho encontra-se os relatórios referentes aos estágios realizados em farmácia comunitária e indústria farmacêutica, onde é feita uma abordagem SWOT (Strengths, Weaknesses, Opportunities and Threats) para discutir os aspetos mais pertinentes dos estágios.<br>The increasing prevalence of diseases related to an aging population, such as neurodegenerative diseases and retinal degenerative diseases, has led to a growing interest in optimizing their treatment.However, drug delivery to the brain and eye is not that easy, due to the presence of barriers that protect these organs. Therefore, it became necessary to develop strategies for the formulation of effective drugs in the treatment of these diseases.The use of nanotechnology to treat diseases has grown interest in recent years. The use of nanoparticles has proven an enormous potential in improving drug pharmacokinetics and its delivery.Due to their characteristics, the use of nanoparticles for the treatment of diseases of the central nervous system and the retina has been extensively studied.This review intends to address the difficulties in overcoming the barriers that protect the brain and the eye, as well as the various studies on the development of nanoparticles with the aim to formulate therapeutic strategies for the treatment of neurodegenerative diseases and retinal degenerative diseases.Throughout this review, mention is made of several published studies in which different nanoparticles with potential to act on the targets of these diseases are addressed.In this work, the reports refering to the internships in communitary pharmacy and pharmaceutical industry are discussed, to evaluate the relevant aspects refering to the internships is used a SWOT (Strengths, Weaknesses, Opportunities and Threats) approach.
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(9714149), Alexandra M. Dieterly. "BREAKING BARRIERS: BLOOD-BRAIN BARRIER PARADIGMS IN BRAIN METASTASES OF LUNG CANCER." Thesis, 2020.
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<p>A multitude of neurologic diseases are increasing in patients that both diminish quality and quantity of life. My dissertation research focused on unraveling the blood-brain barrier’s alterations (BBB), primarily in lung cancer brain metastases, the most common brain metastasis in patients. We optimized a reliable and reproducible mouse model for creating brain metastases using patient derived brain seeking cells of non-small lung cancer (NSCLC) using ultrasound-guided intracardiac injection. I then evaluated brain tissue with qualitative and quantitative immunofluorescence for individual components of the BBB. Using this experimental method, I was able to identify the specific shift of each BBB component over time in NSCLC brain metastases. I then used human brain metastases specimens to demonstrate the clinical relevance of my findings. These results show distinct alterations in the BBB, which have the potential for targeting therapeutic delivery to extend patient survival. I was also able to characterize a novel epithelial-mesenchymal (EMT) phenotype in vertebral metastases of NSCLC in our model, with features similar to those seen in human patients. Most recently, I analyzed patterns of paracellular permeability associated with each BBB component of NSCLC brain metastases which may provide direct passageways for therapeutic delivery. Altogether, this research offered foundational evidence for the future development of targeted novel therapeutics, including nanoparticles. Outside of the brain metastases field, we used an experimental framework to successfully characterize the BBB alterations in a traumatic brain injury model (bTBI). These findings provided the first description of this unique pathology and the framework for developing therapeutics in other neurologic diseases. Although my research work has focused on animal models of disease, future directions based on my research work include the developing a novel 3D BBB-on-chip device to enable high throughput novel therapeutic delivery through the BBB. Long-term, identifying targetable alterations in the restrictive BBB using <i>in vitro</i> and <i>in vivo</i> models provides a potential conduit for effective prevention and treatment of a myriad of neurologic diseases to prolong patient survival and quality of life.</p>
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Cheng-Wen, Tsai. "American Barrier Option." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1301200602161700.
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Chen, Oliver. "Credit barrier models." 2004. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=94712&T=F.
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Tsai, Cheng-Wen, and 蔡承文. "American Barrier Option." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/76029237493536659692.
Full textAbstract:
碩士<br>國立臺灣大學<br>數學研究所<br>94<br>An American barrier option is an option contract in which the option holder receives an American option or becomes nullified conditional on the underlying stock price touching a barrier level. We use the Feynamn-Kac method to value American options and present analytic valuation formulas for American under the Black-Scholes pricing framework. Because the early exercise boundary of the American barrier option is different from the early exercise boundary of the vanilla American option, we claim the in-out parity does not hold.
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Chan, Kwang-Yang, and 詹光陽. "Effect of W barrier in the Al/Barrier/p+n diodes." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/93704559782332997391.
Full textAbstract:
碩士<br>國立交通大學<br>電子研究所<br>83<br>This thesis studies the thermal stability of W contacted p+n
junction diodes using the selective CVD W with the silane
reduction process. For the Al/W/p+n diode with a W layer of
100nm, the device was able to sustain a 450℃ anneal for 30min
without causing any degradation to the device's
characteristics. Degradation occurred when the device was
annealed at 500 ℃, and the XRD analysis showed the appearance
of WAl12 phase. With a thicker W layer of 300nm, the Al/W/p+n
diode was able to raise the stable temperature by about 50℃,
but the diode degraded when it was annealed at 550℃.The
insertion of a 50 nm TiN layer between Al and W successfully
retarded Al-W interdiffusion and WAl12 formation, resulting in
excellent barrier capability up to 575℃. In addition, a simple
self-aligned formation of WNx layer on the W surface by post
CVD-W in situ N2 plasma treatment resulted in another thermally
stable contact system of Al/WNx/W /Si structure. Various
evidence has shown that this post CVD-W N2 plasma treatment
efficiently suppressed the formation of WAl12 and resulted in
an improvement on thermal stability of the W contacted junction
diodes up to 575℃.
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Abdelkader, Sarah Gamal Muhhamed. "Pointing to a place across a barrier : study of barriers effect on human survey knowledge." Master's thesis, 2018. http://hdl.handle.net/10362/33714.
Full textAbstract:
Dissertation submitted in partial fulfilment of the requirements for the degree of Master of Science in Geospatial Technologies<br>People use their mental representation of space to perform activities that involve spatial tasks. Over the past decades, several methods were applied to study the effect of different factors on the way people acquire spatial knowledge.
Through a pointing task, this study attempts to investigate the influence of spatial barriers on human survey knowledge in an outdoor environment. The task involved pointing from the same origin to targets in two separate conditions: one target lies across a barrier and another with no barrier in the pointing direction. The experiment was conducted in three locations: two in Muenster city and one in Dortmund city. A total of 204 random subjects participated in the whole experiments. In each location, the number of subjects participating was divided into two equal groups, each group pointing in only one separate condition. Subjects were asked to give an estimation of the direction to the target using a 360° dial, followed by a question about the direction they would go to get to that target. Pointing errors away from the target were calculated and analysed.
Preliminary results of the study highlighted interesting patterns in the distribution of pointing error in each condition. One major finding of the study reveals that participants made a higher error in case of pointing across a barrier. In two of the study locations, the results show that in such a case, the pointing error is more biased in accordance with people’s path preference when crossing a barrier to reach a destination, while this effect was not observed in the third location.
The study suggests a new viewpoint of understanding how barriers can have an impact on survey knowledge acquisition, and therefore, opens the door to more comprehensive research on this effect. The results also imply that in some cases, such an effect might need to be considered in the process of developing orientation-based applications.