Academic literature on the topic 'Active tissue'
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Journal articles on the topic "Active tissue"
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Kazybekova, S. K., N. K. Bishimbaeyva, A. S. Murtazina, S. M. Tazhibayeva, and R. Miller. "Physico-chemical properties of physiologically active polysaccharides from wheat tissue culture." International Journal of Biology and Chemistry 8, no. 2 (2015): 18–22. http://dx.doi.org/10.26577/2218-7979-2015-8-2-18-22.
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Kim, Soo Hyun, Young Mee Jung, Sang Heon Kim, Young Ha Kim, Jun Xie, Takehisa Matsuda, and Byoung Goo Min. "Mechano-Active Cartilage Tissue Engineering." Advances in Science and Technology 49 (October 2006): 189–96. http://dx.doi.org/10.4028/www.scientific.net/ast.49.189.
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To engineer cartilaginous constructs with a mechano-active scaffold and dynamic compression was performed for effective cartilage tissue engineering. Mechano-active scaffolds were fabricated from very elastic poly(L-lactide-co-ε-carprolactone)(5:5). The scaffolds with 85 % porosity and 300~500 μm pore size were prepared by a gel-pressing method. The scaffolds were seeded with chondrocytes and the continuous compressive deformation of 5% strain was applied to cell-polymer constructs with 0.1Hz to evaluate for the effect of dynamic compression for regeneration of cartilage. Also, the chondrocytes-seeded constructs stimulated by the continuous compressive deformation of 5% strain with 0.1Hz for 10 days and 24 days respectively were implanted in nude mice subcutaneously to investigate their biocompatibility and cartilage formation. From biochemical analyses, chondrogenic differentiation was sustained and enhanced significantly and chondrial extracellular matrix was increased through mechanical stimulation. Histological analysis showed that implants stimulated mechanically formed mature and well-developed cartilaginous tissue, as evidenced by chondrocytes within lacunae. Masson’s trichrome and Safranin O staining indicated an abundant accumulation of collagens and GAGs. Also, ECM in constructs was strongly immuno-stained with anti-rabbit collagen type II antibody. Consequently, the periodic application of dynamic compression can improve the quality of cartilaginous tissue formed in vitro and in vivo.
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Butenas, Saulius, and Kenneth G. Mann. "Active tissue factor in blood?" Nature Medicine 10, no. 11 (November 2004): 1155–56. http://dx.doi.org/10.1038/nm1104-1155b.
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Bogdanov, Vladimir Y., James Hathcock, and Yale Nemerson. "Active tissue factor in blood?" Nature Medicine 10, no. 11 (November 2004): 1156. http://dx.doi.org/10.1038/nm1104-1156.
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Paetsch, C., and L. Dorfmann. "Stability of active muscle tissue." Journal of Engineering Mathematics 95, no. 1 (December 30, 2014): 193–216. http://dx.doi.org/10.1007/s10665-014-9750-1.
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Popović, Marko, Amitabha Nandi, Matthias Merkel, Raphaël Etournay, Suzanne Eaton, Frank Jülicher, and Guillaume Salbreux. "Active dynamics of tissue shear flow." New Journal of Physics 19, no. 3 (March 1, 2017): 033006. http://dx.doi.org/10.1088/1367-2630/aa5756.
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Lowe, Whitney W. "Connective tissue perspectives: Active engagement strokes." Journal of Bodywork and Movement Therapies 4, no. 4 (October 2000): 277–78. http://dx.doi.org/10.1054/jbmt.2000.0166.
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Xi, Wang, Thuan Beng Saw, Delphine Delacour, Chwee Teck Lim, and Benoit Ladoux. "Material approaches to active tissue mechanics." Nature Reviews Materials 4, no. 1 (December 6, 2018): 23–44. http://dx.doi.org/10.1038/s41578-018-0066-z.
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Chirek, Z. "Physiological and biochemical effects of morphactin IT 3233 on callus and tumour tissues of Nicotiana tabacum L. cultured in vitro III. Transamination processes catalysed by aminotransferase L-alanine: 2-oxoglutarate." Acta Societatis Botanicorum Poloniae 43, no. 2 (2015): 169–76. http://dx.doi.org/10.5586/asbp.1974.015.
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An active alanine transaminase was found both in callus and tumour tissues of tobacco. The enzyme is more active in the latter tissue, and the reaction balance is strongly shifted towards alanine production, while in callus tissue towards glutamic acid formation. Morphactin applied to the tissue cultures stimulates markedly the enzyme activity only in callus. A negative correlation was observed between the intensity of transamination processes and enhanced synthesis of proteins in the tissues studied. Morphactin disturbs nitrogen metabolism in the callus tissue. Tumour tissue is more resistant to the action of this substance. The different hormonal activities in these tissues may be the cause of the different effects of morphactin.
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Bogdan, Michał J., and Thierry Savin. "Fingering instabilities in tissue invasion: an active fluid model." Royal Society Open Science 5, no. 12 (December 2018): 181579. http://dx.doi.org/10.1098/rsos.181579.
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Metastatic tumours often invade healthy neighbouring tissues by forming multicellular finger-like protrusions emerging from the cancer mass. To understand the mechanical context behind this phenomenon, we here develop a minimalist fluid model of a self-propelled, growing biological tissue. The theory involves only four mechanical parameters and remains analytically trackable in various settings. As an application of the model, we study the evolution of a two-dimensional circular droplet made of our active and expanding fluid, and embedded in a passive non-growing tissue. This system could be used to model the evolution of a carcinoma in an epithelial layer. We find that our description can explain the propensity of tumour tissues to fingering instabilities, as conditioned by the magnitude of active traction and the growth kinetics. We are also able to derive predictions for the tumour size at the onset of metastasis, and for the number of subsequent invasive fingers. Our active fluid model may help describe a wider range of biological processes, including wound healing and developmental patterning.
Dissertations / Theses on the topic "Active tissue"
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Huang, Boyang. "Electro-active scaffolds for bone tissue engineering." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/electroactive-scaffolds-for-bone-tissue-engineering(e4374a7f-47fe-418f-a515-fe5a37668aa8).html.
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Bone is a highly hierarchical tissue which is able to heal and remodel in case of small defects and damage. For critical-size defects, the most commonly used approach requires the use of synthetic grafts. These grafts, also known as scaffolds, are physical substrates designed for cell attachment, proliferation and differentiation. Scaffolds for bone applications must be biocompatible, biodegradable, and highly porous, presenting mechanical properties similar to bone and surface characteristics that promote cell-scaffold interactions. The final properties of a scaffold strongly depend on both material compositions and process conditions. This research project investigates different aspects related to the design fabrication and characterization of bioactive electro-active scaffolds. Scaffolds were produced using an extrusion-based additive manufacturing system and different material compositions based on Poly (ε-caprolactone) (PCL) mixed with hydroxyapatite (HA), β-tri-calcium phosphate (TCP) and multi-wall carbon nanotubes (MWCNTs) were investigated. HA and TCP are biocompatible and degradable ceramics related to improve the bioactivity of the scaffolds and MWCNTs were selected to improve mechanical properties and due to their excellent electrical conductivity characteristics, to promote both cell-cell and cell-substrate communication. Experimental work was conducted to characterize both pre-processed materials and produced scaffolds evaluating the rheological, mechanical, thermal, chemical and biological properties. Rheological tests show that printability strongly depends on the concentration of the inorganic fillers (MWCNTs, HA and TCP) and processing parameters such as temperature, screw rotational velocity and deposition velocity. The addition of MWCNTs, HA and TCP can enhance the compressive modulus of PCL scaffolds from 48 MPa to 75 MPa in the case of PCL/HA, or 88 MPa in the case of PCL/TCP and PCL/MWCNTs. Biological results show that all scaffolds containing MWCNTs, HA and TCP are biocompatible (more than 80% cell viability), bioactive (40% increase for TCP, 60% increase for HA and 86% increase for MWCNTs) and osteoconductive (significant increase of ALP activity). Results also show that the addition of MWCNTs improves the osteoinductive properties and the presence of nano-sized HA improves the mineralization process. This research shows that PCL/HA/MWCNTs can be viable scaffolds for bone tissue engineering, providing a promising way for bone tissue regeneration.
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Bowyer, Stuart. "Active constraints for robotic surgery in deforming tissue." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/51553.
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Active constraints are collaborative human-robot control algorithms which have a well-established history of use within robot assisted surgery research. This control strategy anisotropically regulates the motion of a human user in such a way that it effectively combines the competencies of surgeons and robots, allowing for improved clinical outcomes and surgeon experience. The significant majority of research previously presented for active constraints focuses on their application to static procedures, where the surgical environment is assumed to be rigid throughout. In this thesis, several research contributions are presented which assist with applying active constraints in surgical procedures within deforming soft tissue. The primary contribution is the formulation of a novel haptic control algorithm, based on friction, which can effectively guide a surgeon in both positioning and orienting a surgical instrument, while guaranteeing that the haptic interaction is energetically dissipative. The proven dissipative formulation of these 'dynamic frictional constraints' ensures that the surgeon always has overall control of a procedure and makes the system resilient to limitations and errors in the robot's comprehension of the surgical environment. To apply active constraints within deforming tissue, it is necessary to compute the geometric relationship between the surgical instruments and the constrained anatomy. A novel bounding volume is proposed which, when used in a hierarchy, exploits the limits of soft tissue deformations to increase the resolution of constraint geometries that can be used at stable control rates. The experimental validation of these research contributions in a clinically realistic nerve dissection simulation and in non-clinical dynamic path-following tasks, shows significant benefits to the user in several metrics characterising surgical accuracy and precision. These results demonstrate that the proposed enhancements of active constraints could lead to increased surgeon performance, fewer complications and improved clinical outcomes in soft tissue surgical procedures.
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Andersson, Jonas. "Adipose tissue as an active organ : blood flow regulation and tissue-specific glucocorticoid metabolism." Doctoral thesis, Umeå universitet, Medicin, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-48415.
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Background: Despite advances in the treatment of atherosclerosis, cardiovascular disease is the leading cause of death worldwide. With the population getting older and more obese, the burden of cardiovascular disease may further increase. Premenopausal women are relatively protected against cardiovascular disease compared to men, but the reasons for this sex difference are partly unknown. Redistribution of body fat from peripheral to central depots may be a contributing factor. Central fat is associated with hyperlipidemia, hyperglycemia, hypertension, and insulin resistance. Two possible mediators of these metabolic disturbances are tissue-specific production of the stress hormone cortisol and adipose tissue blood flow (ATBF). The aim of this thesis was to determine the adipose tissue production of cortisol by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and to investigate the regulation of ATBF. Materials and Methods: Cortisol release was estimated by labeled cortisol infusions and tissue-specific catheterizations of subcutaneous and visceral adipose tissue (VAT) in men. We investigated ATBF by 133Xe-washout and its relation to autonomic activity, endothelial function, adipose tissue distribution, and adipokines in different groups of women. We further investigated the effect of two diets and of weight loss on ATBF in women. Results: We demonstrated significant cortisol release from subcutaneous adipose tissue in humans. Splanchnic cortisol release was accounted for entirely by the liver. Cortisol release from VAT (to the portal vein) was not detected. ATBF decreased according to increasing weight and postmenopausal status, and the level of blood flow was associated with nitric oxide (NO) activity and autonomic activity. ATBF was also highly associated with leptin levels and both subcutaneous adipose tissue and VAT areas. After 6 months of diet and weight reduction, a significant difference in ATBF was observed between diet groups. Conclusions: Our data for the first time demonstrate the contributions of cortisol generated from subcutaneous adipose tissue, visceral tissues, and liver by 11β-HSD1. ATBF is linked to autonomic activity, NO activity, and the amount of adipose tissue (independent of fat depot). Postmenopausal overweight women exhibited a loss of ATBF flexibility, which may contribute to the metabolic dysfunction seen in this group. Weight loss in a diet program could not increase the ATBF, although there were ATBF differences between diet groups. The results will increase understanding of adipose tissue biology and contribute to the development of treatment strategies targeting obesity and obesity-related disorders.
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Kamper, Marina. "Active contraction of the left ventricle with cardiac tissue modelled as a micromorphic medium." Master's thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/31132.
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The myocardium is composed of interconnected cardiac fibres which are responsible for contraction of the heart chambers. There are several challenges related to computational modelling of cardiac muscle tissue. This is due in part to the anisotropic, non-linear and time-dependent behaviour as well as the complex hierarchical material structure of biological tissues. In general, cardiac tissue is treated as a non-linear elastic and incompressible material. Most computational studies employ the theories of classical continuum mechanics to model the passive response of the myocardium and typically assume the myocardium to be either a transversely isotropic material or an orthotropic material. In this study, instead of a classical continuum formulation, we utilise a micromorphic continuum description for cardiac tissue. The use of a micromorphic model is motivated by the complex microstructure and deformations experienced by cardiac fibres during a heartbeat. The micromorphic theory may be viewed as an extension of the classical continuum theory. Within a micromorphic continuum, continuum particles are endowed with extra degrees of freedom by attaching additional vectors, referred to as directors, to the particles. In this study the directors are chosen such that they represent the deformation experienced by the cardiac fibres. In addition to the passive stresses, the myocardium experiences active stresses as a result of the active tension generated by cardiac fibres. The active tension in the heart is taken to be a function of the sarcomere length, intracellular calcium concentration and the time after the onset of contraction. Experimental studies show that the active behaviour of the myocardium is highly dependent on the tissue arrangement in the heart wall. With a classical continuum description, the sarcomere length is usually defined as a function of the stretch in the initial fibre direction. To allow for a more realistic description of the active behaviour, we define the sarcomere orientation, and consequently also the sarcomere stretch, as a function of the director field. Furthermore, we use the director field to describe the direction in which contraction takes place. The intent of this study is to use a micromorphic continuum formulation and an active-stress model to investigate the behaviour of the left ventricular myocardium during a heartbeat. The simulated results presented here correspond well with typical ventricular mechanics observed in clinical experiments. This work demonstrates the potential of a micromorphic formulation for analysing and better understanding ventricular mechanics.
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Behbahani, Homira. "Immune dysregulation in HIV-1 infected lymphoid tissue /." Stockholm, 2002. http://diss.kib.ki.se/2002/91-7349-193-4.
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Booth, Andrew. "Controlled release of active compounds from a magnetic nanoparticle-vesicle aggregate nanomaterial." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/controlled-release-of-active-compounds-from-a-magnetic-nanoparticlevesicle-aggregate-nanomaterial(5c87df99-8ab3-4965-bdc2-081333be1ef9).html.
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Non-invasive and controlled release of bioactive compounds is an important goal in the development of drug delivery systems and novel biomaterials for tissue engineering. This project aims to exert spatio-temporal control over the release of bioactive compounds from phospholipid vesicle carriers by crosslinking them with superparamagnetic iron oxide nanoparticles to form a magnetic release nanostructure. The magnetic properties of the nanoparticles allow release to be triggered by an alternating magnetic field (AMF), which induces localised heating and “melts” the vesicle membranes. The aggregates can also be manipulated in space by a static magnetic field to create patterned materials. Incorporation of these aggregates into hydrogels has created novel responsive biomaterials. Controlled release of ascorbic acid-2-phosphate has been used to induce collagen production by chondrocytes, demonstrating an AMF triggered cellular response in vitro. The existing system has been redesigned after detailed characterisation and assessment of the performance of each component. Magnetic release has been extensively assessed using fluorescence techniques to quantify release, and optimised through the development of new silica-derived nanoparticle coatings and aggregate formulations informed by quantitative characterisation of nanoparticle functionalisation. The replacement of calcium alginate hydrogels as a 3D cell culture matrix with hyaluronic acid- based hydrogels was found to eliminate gel-induced leakage of vesicle contents and also improves the compatibility of the system with a greater range of cell types. Recently the effective encapsulation and AMF-triggered release of proteins including enzymes has been demonstrated and released enzymes have been demonstrated to retain their activity. Released trypsin was shown to retain proteolytic activity while hyaluronidase released into hyaluronan-derived hydrogels has been demonstrated to influence the rheological properties of the gel. A galactose-terminated lipid has been synthesised that enables specific targeting of the asialoglycoprotein (ASGPR) cell surface receptor receptor found in human hepatocytes, demonstrating the potential for customisation of the MNPV system to particular requirements.
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Degache, Amelie. "Electrical impedance spectroscopy applied to the chronic monitoring of the fibrosis induced by cardiac active implants." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0432.
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Les arythmies cardiaques représentent environ 50% des maladies cardiovasculaires qui sont la première cause de mortalité dans le monde. Les implants médicaux jouent un rôle majeur dans le traitement de ces arythmies. En France c’est environ 250 000 patients qui sont équipés d’un implant cardiaque et qui nécessitent un suivi régulier. Ces implants utilisent les dernières technologies de micro-nano électronique et possèdent un boitier de stimulation qui est placé en sous-cutané, connecté aux électrodes via une sonde intraveineuse. Un des principaux points faibles de tout implant réside dans l’interface électrode-tissu, en raison d’une réaction inflammatoire soutenue appelée la fibrose. Ce phénomène compromet la biocompatibilité de l’implant, encapsulant la sonde avec un tissu « isolant ». Cela crée des adhérences le long de la sonde et au niveau de l’électrode, ce qui entraine souvent une hausse des seuils de stimulation au cours du temps et une diminution des durées de vie des batteries. Cette réponse est connue et peut être minimisée lors de l’implantation grâce à des sondes à élution de stéroïdes mais la fibrose reste tout de même un obstacle pour les implants, justifiant notre intérêt d’étude sur le long terme de la biocompatibilité des implants cardiaques.La compréhension des mécanismes de la fibrose est primordiale pour ce travail. La fibrose est due à une activation et différentiation de certaines cellules cardiaques sous une contrainte mécanique, et le tissu cardiaque se retrouve modifié localement. Pour caractériser cette modification, on utilise la mesure d’impédance qui consiste à envoyer un courant électrique sinusoïdal I et recueillir la tension résultante U dans le tissu, l’impédance Z est le ratio U/I. en fonction de la fréquence de mesure, on peut explorer le tissu à une échelle microscopique ou macroscopique. Comme les patients sont déjà équipés de sondes cardiaques reliées à un circuit de stimulation qui peut aussi enregistrer l’activité cardiaque, l’idée principale de ce travail est d’examiner l’utilisation d’une mesure électrique qui pourrait caractériser l’encapsulation fibrotique de la sonde, avec pour objectif final d’embarquer cette méthode de caractérisation dans le circuit implanté. Cela nous amène à la problématique de ce projet : est-ce que la fibrose qui se développe autour des sondes cardiaques a une signature électrique ?Mon travail de thèse s’organise en trois axes. Deux axes expérimentaux sont conduits aux niveaux cellulaire et tissulaire. On envisage en plus un axe discutant la faisabilité de mesures d’impédance embarquées pour des conditions proches de l’in vivo. La partie tissulaire ou ex vivo présente la caractérisation de différentes natures de tissu, sain ou collagéneux, et a été développée à l’IHU LIRYC, sur des ventricules de cochons ou de brebis avec des sondes cardiaques implantées chez l’homme. Les spectres d’impédance obtenus sont analysés avec des modèles électriques connus et dont les paramètres sont extraits pour chaque type de tissus. Une analyse statistique montre que les deux natures de tissu sont caractérisées par des paramètres significativement différents. La partie cellulaire ou in vitro présente la caractérisation électrique, par mesure d’impédance, et biologique, par marquages immunocytochimiques, d’un modèle cellulaire de fibrose. Ce modèle est développé en cultivant des cellules cardiaques humaines, activées ou non par un facteur de croissance. Après une analyse statistique, les valeurs d’impédance des cultures activées montrent une différence significative par rapport aux cultures non activées, tandis que la caractérisation biologique montre une augmentation du nombre des cellules activées au cours du temps. Le dernier axe présente des résultats préliminaires sur de mesure d’impédance embarquée en vue d’une utilisation ultérieure in vivoCardiac arrhythmias represent about 50% of the cardiovascular diseases which are the first cause of mortality in the world. Implantable medical devices play a major role for treating these cardiac arrhythmias. In France, about 250.000 patients are equipped with an implanted device for arrhythmia treatment and need a regular monitoring. These devices use the latest technology of micro-nano-electronics and integrate a subcutaneous pulse generator connected to electrodes placed into the heart via intravenous leads. One of the main weaknesses of every implantable device lies in the electrode-tissue interface due to a sustained inflammatory response called fibrosis. This phenomenon jeopardizes the device biocompatibility, because it encapsulates the stimulation lead with an “insulating” tissue, creating adherences along the lead and often leading to an increase of the stimulation threshold over time and a larger electrical consumption. This response is well-known and minimized during the implantation surgery thanks the use of steroid-elution electrodes, however fibrosis still remains an impediment even for the most recent devices, enhancing the interest of studying long-term biocompatibility of cardiac implanted devices.The understanding of fibrosis mechanisms is essential for this work. It consists in some cardiac cells activation and differentiation under a mechanical stress, inducing fibrosis initiation and modifying locally the active cardiac tissue. To characterize this modification, we use electrical impedance measurements, consisting in sending a sinusoidal electrical current I and then measuring the resulting voltage U in the tissue; the impedance Z is the U/I ratio. Depending on the frequency of the measurement signal, we can explore the tissue from the microscopic to the macroscopic scales. As a patient is already equipped with cardiac leads connected to a stimulation device which can also record the cardiac electrical activity, the main idea of this work is to investigate the use of an electrical measurement that could characterize the fibrotic lead encapsulation, with the final objective to embed this characterization method in the implanted circuit. This brings us to the main question of our project: does the fibrosis developing around the cardiac leads have an electrical signature?My thesis work is organized along three axes. Two experimental axes are conducted at cellular and tissue levels, on in vitro or ex vivo models. In addition, an axis studying the feasibility of embedded impedance measurement for in vivo mimicking conditions is also discussed. The ex vivo part presents the characterization of tissue of different natures, healthy or collagenous, it was developed with the IHU LIRYC laboratory, on porcine or ovine cardiac tissue (ventricles mainly), with stimulation electrodes used on patients The impedance spectra are analyzed using a known electrical model from which characteristic parameters of the two tissue types are extracted. After statistical analysis, these parameters are found to be significantly different allowing us to distinguish both tissue types. The in vitro part presents the electrical characterization, using impedance measurements, in parallel to the biological characterization, using immunocytochemistry, of a cellular fibrosis model. It consists in culturing human cardiac cells, activated or not by a growth factor. After a statistical analysis, the impedance values show a significantly different signature for cultures with growth factor, with respect to sham cultures, while the biological characterization confirmed the presence of more activated and differentiated cells over time. The last axis gives preliminary results of embedded impedance measurements in custom circuits
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Izumi, Hideki. "Tissue factor pathway inhibitor-2 suppresses the production of active matrix metalloproteinase-2 and is down-regulated in cells harboring activated ras oncogenes." Kyoto University, 2001. http://hdl.handle.net/2433/151452.
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Abbott, Eric Justin. "Cutting trees with lasers : isolation of high quality RNA, enzymatically active protein and metabolites from individual tissue types of white spruce stems obtained using laser microdissection." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/24249.
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Laser-assisted microdissection has been established for isolation of individual tissue types from herbaceous plants. However, there are few reports of cell- and tissue-specific analysis in woody perennials. While microdissected tissues are commonly analyzed for gene expression, reports of protein, enzyme activity and metabolite analysis are limited due in part to an inability to amplify these molecules. Conifer stem tissues are organized in a regular pattern with xylem, phloem and cortex development controlled by the activity of the cambial zone (CZ). Defense responses of conifer stems against insects and pathogens involve increased accumulation of terpenoids in cortical resin ducts (CRDs) and de novo formation of traumatic resin ducts from CZ initials. Woody plants are difficult to study at the level of individual tissues or cell-types and are thus good candidates for application of LMD. This thesis describes robust methods for isolation of individual tissue-types from white spruce (Picea glauca) stems for analysis of RNA, enzyme activity and metabolites. A tangential cryosectioning approach was important for obtaining large quantities of CRD and CZ tissues using LMD. Differential expression is reported for genes involved in terpenoid metabolism between CRD and CZ tissues and in response to treatment with methyl jasmonate (MeJA). Transcript levels of β-pinene synthase and levopimaradiene/abietadiene synthase were constitutively higher in CRDs, but induction was stronger in CZ in response to MeJA. 3-Carene synthase was more strongly induced in CRDs compared to CZ. A differential induction pattern was observed for 1-deoxyxyulose-5-phosphate synthase, which was up-regulated in CRDs and down-regulated in CZ. We identified terpene synthase enzyme activity in CZ protein extracts and terpenoid metabolites in both CRD and CZ tissues. Combined analysis of transcripts, proteins and metabolites of individual tissues will facilitate future characterization of complex processes of woody plant development, including periodic stem growth and dormancy, cell specialization, and defense and may be applied widely to other plant species.
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Ranft, Jonas M. "Mechanics of Growing Tissues: A Continuum Description Approach." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-105479.
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During development, higher organisms grow from a single fertilized egg cell to the adult animal. The many processes that lead to the eventual shape of the developed organism are subsumed as morphogenesis, which notably involves the growth of tissues by repeated rounds of cell division. Whereas coordinated tissue growth is a prerequisite for animal development, excessive cell division in adult animals is the key ingredient to cancer. In this thesis, we investigate the collective organization of cells by cell division and cell death. The multicellular dynamics of growing tissues is influenced by mechanical conditions and can give rise to cell rearrangements and movements. We develop a continuum description of tissue dynamics, which describes the stress distribution and the cell flow field on large scales. Cell division and apoptosis introduce stress sources that, in general, are anisotropic. By combining cell number balance with dynamic equations for the stress source, we show that the tissue effectively behaves as a viscoelastic fluid with a relaxation time set by the rates of division and apoptosis. If the tissue is confined in a fixed volume, it reaches a homeostatic state in which division and apoptosis balance. In this state, cells undergo a diffusive random motion driven by the stochasticity of division and apoptosis. We calculate the effective diffusion coefficient as a function of the tissue parameters and compare our results concerning both diffusion and viscosity to simulations of multicellular systems. Introducing a second material component that accounts for the extracellular fluid, we show that a finite permeability of the tissue gives rise to additional mechanical effects. In the limit of long times, the mechanical response of the tissue to external perturbations is confined to a region of which the size depends on the ratio of tissue viscosity and cell-fluid friction. The two-component description furthermore allows to clearly distinguish the different contributions to the isotropic part of the mechanical stress, i.e., the fluid pressure and the stress exerted by cells. Last but not least, we study the propagation of an interface between two different cell populations within a tissue driven by differences in the mechanical control of the rates of cell division and apoptosis. Combining simple analytical limits and numerical simulations, we distinguish two different modes of propagation of the more proliferative population: a diffusive regime in which relative fluxes dominate the expansion, and a propulsive regime in which the proliferation gives rise to dominating convective flowsDie Entwicklung höherer Organismen beginnt mit einer einzelnen befruchteten Eizelle und endet beim erwachsenen Tier. Die vielen Prozesse, die zur endgültigen Form des entwickelten Organismus führen, werden als Morphogenese zusammengefasst; diese umfasst insbesondere das Wachstum von Geweben durch wiederholte Zellteilungszyklen. Während koordiniertes Gewebewachstum eine Voraussetzung normaler Entwicklung ist, führt übermäßige, unkontrollierte Zellteilung letztlich zu Krebs. In dieser Arbeit untersuchen wir den Einfluss von Zellteilung und Zelltod auf die Organisation von Zellen in Geweben. Die Dynamik wachsender Gewebe wird durch mechanische Bedingungen beeinflusst, die u.a.~Anlass zu Zellbewegungen sein können. Wir entwickeln eine Kontinuumsbeschreibung der Gewebedynamik, die die mechanischen Spannungen und das Zellströmungsfeld auf großen Skalen beschreibt. Zellteilung und Apoptose wirken als Spannungsquellen, die in der Regel anisotrop sind. Indem wir die Erhaltungsgleichung für die Zellanzahldichte mit dynamischen Gleichungen für die Spannungsquellen kombinieren, zeigen wir, dass sich das Gewebe effektiv wie eine viskoelastische Flüssigkeit verhält, deren Relaxationszeit von Zellteilungs- und Apoptose-Raten abhängt. Wenn das Gewebe in einem gegebenen Volumen eingeschlossen ist, erreicht es einen homöostatischen Zustand, in dem Zellteilung und der Apoptose im Gleichgewicht sind. In diesem Zustand unterliegen die Zellen einer diffusiven Bewegung aufgrund der Stochastizität von Zellteilung und Apoptose. Wir berechnen den effektiven Diffusionskoeffizienten als Funktion der Gewebeparameter und vergleichen unsere Ergebnisse sowohl hinsichtlich der Diffusion und als auch der Viskosität mit numerischen Simulationen solcher vielzelliger Systeme. Die Berücksichtigung der extrazellulären Flüssigkeit als einer zweiten Materialkomponente erlaubt uns zu zeigen, dass eine endliche Permeabilität des Gewebes zusätzliche mechanische Effekte bedingt. Auf langer Zeitskalen bleibt die mechanische Reaktion des Gewebes auf externe Störungen auf einen Bereich beschränkt, dessen Größe vom Verhältnis der Gewebeviskosität zum Permeabilitätskoeffizienten abhängt. Die Zweikomponenten-Beschreibung erlaubt darüber hinaus eine klare Unterscheidung der verschiedenen Beiträge zum isotropen Teil der mechanischen Spannung, d.h., des hydrodynamischen und des von Zellen ausgeübten Drucks. Zuletzt untersuchen wir die Dynamik einer Grenzfläche zwischen zwei verschiedenen Zellpopulationen innerhalb eines Gewebes, die durch Unterschiede in der mechanischen Kontrolle der effektiven Zellteilungsraten angetrieben wird. Mithilfe der Kombination einfacher analytischer Grenzfälle und numerischer Simulationen zeigen wir, dass zwei unterschiedliche Ausbreitungsmodi unterschieden werden können: ein diffusives Regime, in dem relative Flüsse die Expansion der stärker wachsenden Zellpopulation dominieren, sowie ein Regime, in dem die Grenzfläche durch konvektive Strömungen angetrieben wird
Les organismes supérieurs se développent à partir d\'une seule cellule fécondée jusqu\'à l\'animal adulte. Les nombreux processus qui conduisent à la forme finale de l\'organisme sont connus sous le nom de morphogenèse, qui comprend notamment la croissance des tissus par des cycles répétés de division cellulaire. Alors que la croissance coordonnée des tissus est une condition nécessaire au développement des animaux, la division cellulaire excessive chez les animaux adultes est l\'ingrédient clé du cancer. Dans cette thèse, nous étudions l\'organisation collective des cellules par division et mort cellulaire. La dynamique multicellulaire des tissus en croissance est influencée par des conditions mécaniques et peut donner lieu à des réarrangements ainsi qu\'à des mouvements cellulaires. Nous élaborons une description continue de la dynamique des tissus qui décrit la distribution des contraintes et le champ d\'écoulement des cellules sur de grandes échelles. La division cellulaire et l\'apoptose introduisent des sources de contraintes qui, en général, sont anisotropes. En combinant l\'équation de conservation du nombre de cellules avec des équations dynamiques des sources de contraintes, nous montrons que le tissu se comporte de manière effective comme un fluide viscoélastique avec un temps de relaxation fixé par les taux de division et d\'apoptose. Si le tissu est confiné dans un volume donné, il atteint un état homéostatique dans lequel division et apoptose s\'équilibrent. Dans cet état, les cellules subissent un mouvement diffusif aléatoire dû à la stochasticité de la division et de l\'apoptose. Nous calculons le coefficient de diffusion effectif en fonction des paramètres du tissu et comparons nos résultats concernant à la fois la diffusion et la viscosité à des simulations numériques de tels systèmes multicellulaires. En introduisant un deuxième composant qui représente le liquide extracellulaire, nous montrons qu\'une perméabilité finie du tissu donne lieu à des effets mécaniques supplémentaires. Dans la limite des temps longs, la réponse mécanique du tissu à des perturbations extérieures est confinée à une région dont la taille dépend du rapport entre la viscosité tissulaire et le coefficient de frottement entre les cellules et le liquide extracellulaire. La description à deux composants permet en outre de distinguer clairement les différentes contributions à la partie isotrope de la contrainte mécanique, c\'est-à-dire la pression du fluide et la contrainte exercée par les cellules. Finalement, nous étudions la propagation d\'une interface entre deux populations de cellules différentes, due à des différences dans le contrôle mécanique des taux de division et de mort cellulaire. En combinant de simples limites analytiques et des simulations numériques, nous distinguons deux modes de propagation différents de la population cellulaire la plus proliférante : un régime diffusif dans lequel les flux relatifs dominent l\'expansion, et un régime de propulsion dans lequel la prolifération domine et entraine des flux convectifs
Books on the topic "Active tissue"
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service), SpringerLink (Online, ed. Active Implants and Scaffolds for Tissue Regeneration. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg, 2011.
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Zilberman, Meital, ed. Active Implants and Scaffolds for Tissue Regeneration. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-18065-1.
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Treinen, Moslen Mary, and Smith Charles V, eds. Free radical mechanisms of tissue injury. Boca Raton: CRC Press, 1992.
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Cassidy, Nicola Marie. Isolation of extracellular matrix components from dentine active in dental cytodifferentiation and tissue repair. Birmingham: University of Birmingham, 1995.
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Nowak, Alicja. Metabolizm tkanki kostnej u aktywnych fizycznie młodych mężczyzn-- wpływ wysiłku fizycznego =: Bone tissue metabolism in active young men--influence of physical exercise. Poznań: Akademia Wychowania Fizycznego im. Eugeniusza Piaseckiego, 2005.
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Miller, Franklin G. Death, dying, and organ transplantation: Reconstructing medical ethics at the end of life. Oxford: Oxford University Press, 2011.
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Robert, Truog, ed. Causing death: Reconstructing medical ethics at the end of life. Oxford: Oxford University Press, 2011.
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Clark, J. Andrew. Scar tissue. [Santa Barbara, CA?]: Lip Think Press in conjunction with Dial R Studios, 2007.
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Crasbercu, Corinne. Tout en patch' ...: Plaids, sacs et autres bricoles. [Paris]: Marabout, 2010.
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Reid, Helen M. Tissue inhibitors of matrix metalloproteinases are modulated differently by 12-0-Tetradeconoylphorbol-13-actate (TPA) and 1,1,1-Trichoro-2,2-Bis-(p-Chlorophenyl)-ethane (DDT). [S.l: The Author], 1997.
Find full textBook chapters on the topic "Active tissue"
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Mizrahi, Boaz, Christopher Weldon, and Daniel S. Kohane. "Tissue Adhesives as Active Implants." In Active Implants and Scaffolds for Tissue Regeneration, 39–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/8415_2010_48.
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Kim, Soo Hyun, Young Mee Jung, Sang Heon Kim, Young Ha Kim, Jun Xie, Takehisa Matsuda, and Byoung Goo Min. "Mechano-Active Cartilage Tissue Engineering." In Advances in Science and Technology, 189–96. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/3-908158-05-2.189.
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Hitoshi, Hori, Nakagawa Yoshinori, Ojima Hiroshi, Niijima Takehiro, and Terada Hiroshi. "Biologically Active Cyanine Dyes as Probes for the Identification of Active Oxygen Species." In Oxygen Transport to Tissue XIV, 255–60. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3428-0_27.
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DeJong, T. M. "Understanding the long-term storage sink." In Concepts for understanding fruit trees, 92–95. Wallingford: CABI, 2022. http://dx.doi.org/10.1079/9781800620865.0010.
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Abstract Similar to short-term starch storage in the chloroplasts of the leaves that serves to buffer growth of organs from carbohydrate shortages due to diurnal patterns of photosynthesis related to daily patterns of light and darkness, trees also have long-term storage capacity to enable them to supply the minimal respiratory needs of tissues during the winter and resume growth in the spring when trees are still leafless. This long-term storage of carbohydrates and some minerals occurs primarily in the phloem and xylem tissue of the branches, trunk and roots. While active phloem tissue has higher concentrations of stored carbohydrates than xylem tissue, the mass of active xylem storage tissue is many times the mass of the active phloem tissue. Thus, xylem tissue comprises the largest storage compartment of temperate deciduous fruit trees. This chapter deals with understanding the long-term storage sink in fruit trees.
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Nardo, Paolo Di, Marilena Minieri, Annalisa Tirella, Giancarlo Forte, and Arti Ahluwalia. "Inherently Bio-Active Scaffolds: Intelligent Constructs to Model the Stem Cell Niche." In Myocardial Tissue Engineering, 29–47. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/8415_2010_58.
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Reichard, Chad A., and Eric A. Klein. "Tissue-Based Markers for Risk Prediction." In Active Surveillance for Localized Prostate Cancer, 121–33. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-62710-6_12.
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Holden, A. V. "Idiosyncracies of Cardiac Tissue as an Excitable Medium." In Nonlinear Waves in Active Media, 170–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74789-2_23.
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Donovan, Michael J., and Carlos Cordon-Cardo. "Predicting High-Risk Disease Using Tissue Biomarkers." In Active Surveillance for Localized Prostate Cancer, 23–34. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-61779-912-9_3.
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Dorati, Rossella, Claudia Colonna, Ida Genta, and Bice Conti. "Polymer Scaffolds for Bone Tissue Regeneration." In Active Implants and Scaffolds for Tissue Regeneration, 259–85. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/8415_2010_59.
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Igwe, John, Ami Amini, Paiyz Mikael, Cato Laurencin, and Syam Nukavarapu. "Nanostructured Scaffolds for Bone Tissue Engineering." In Active Implants and Scaffolds for Tissue Regeneration, 169–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/8415_2010_60.
Full textConference papers on the topic "Active tissue"
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Gajdošechová, Lucia, Štefan Zorad, Daniela Ježová, Mária Ondrejčáková, Miroslava Eckertová, and Katarína Kršková. "Oxytocin remodels adipose tissue." In XIIth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2011. http://dx.doi.org/10.1135/css201113045.
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Kim, Sang-Heon, Youngmee Jung, Soo Hyun Kim, and Young Ha Kim. "Mechano-active Tissue Engineering." In In Commemoration of the 1st Asian Biomaterials Congress. WORLD SCIENTIFIC, 2008. http://dx.doi.org/10.1142/9789812835758_0007.
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Zorad, Štefan, Daniela Ježová, Ľudmila Szabová, Ladislav Macho, and Katarína Tybitanclová. "Insulin receptors in adipose tissue of rats with monosodium glutamate-induced obesity." In VIIIth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2003. http://dx.doi.org/10.1135/css200306125.
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Tybitanclová, Katarína, and Štefan Zorad. "Changes of AT1 receptor expression in rat adipose tissue with respect to adiposity." In IXth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2005. http://dx.doi.org/10.1135/css200508097.
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Baculíková, Miroslava, Lucia Gajdošechová, Roderik Fiala, Peter Grančič, Anton Kebis, Marián Kukan, and Štefan Zorad. "Reduced angiotensin II mediated protein oxidation in adipose tissue of 12-week-old Zucker rats." In XIth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2009. http://dx.doi.org/10.1135/css200911004.
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Li, En, Shuichi Makita, Deepa Kasaragod, and Yoshiaki Yasuno. "Simultaneous tissue birefringence and deformation measurement by polarization sensitive optical coherence elastography with active compression (Conference Presentation)." In Optical Elastography and Tissue Biomechanics V, edited by Kirill V. Larin and David D. Sampson. SPIE, 2018. http://dx.doi.org/10.1117/12.2288056.
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Nagatomi, Jiro, Michael B. Chancellor, and Michael S. Sacks. "Active Biaxial Mechanical Properties of Bladder Wall Tissue." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-43146.
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The urinary bladder is a smooth muscle organ whose main functions are to store and to void urine. Since the most important aspect of the storage function of the bladder is to maintain low intravesical pressure in order to protect the upper urinary tract from backflow of urine, the compliance of the bladder wall is one of the key functional paramters to assess the health of this organ. Previously, our laboratory reported, for the first time, the biaxial mechanical properties of bladder wall tissue in the inactive state (in the absence of calcium in the testing bath solution and thus smooth muscle contraction was abolished) (Gloeckner et al. 2002). The bladder in vivo, however, normaly exhibits passive smooth muscle tone during filling and active contraction during voiding. Therefore, in order to completely characterize the bladder tissue mechanical behaviors, it is necessary to examine the load-deformation relationship of the bladder under the passive and active states. In the present study, a novel experimental model was designed to allow collection of biaxial stress-strain data from urinary bladder wall tissue under passive, active and inactive states.
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Chumtong, Puwanan, Masaru Kojima, Kenichi Ohara, Mitsuhiro Horade, Yasushi Mae, Yoshikatsu Akiyama, Masayuki Yamato, and Tatsuo Arai. "An active microscaffold for applications in tissue engineering." In 2013 International Symposium on Micro-NanoMechatronics and Human Science (MHS). IEEE, 2013. http://dx.doi.org/10.1109/mhs.2013.6710404.
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Tanaka, Nobuyuki, Mitsuru Higashimori, and Makoto Kaneko. "Active sensing for viscoelastic tissue with coupling effect." In 2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2008. http://dx.doi.org/10.1109/iembs.2008.4649102.
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Stanitsas, Panagiotis, Anoop Cherian, Alexander Truskinovsky, Vassilios Morellas, and Nikolaos Papanikolopoulos. "Active convolutional neural networks for cancerous tissue recognition." In 2017 IEEE International Conference on Image Processing (ICIP). IEEE, 2017. http://dx.doi.org/10.1109/icip.2017.8296505.
Full textReports on the topic "Active tissue"
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Pesis, Edna, and Mikal Saltveit. Postharvest Delay of Fruit Ripening by Metabolites of Anaerobic Respiration: Acetaldehyde and Ethanol. United States Department of Agriculture, October 1995. http://dx.doi.org/10.32747/1995.7604923.bard.
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The use of pretreatments for 24 h prior to storage, under anaerobic condtions, or in the presence of the natural metabolic products, acetaldehyde (AA) and ethanol, to delay fruit ripening, was found to be effective with several climacteric fruits, among them avocado, mango, peach and tomato. The delay in ripening of avocado, peach and tomato was accompanied by inhibition of ethylene production and of fruit softening. The maintenance of fruit firmness was associated with a decrease in the activities of cell-wall-degrading enzymes, including endoglucanases (Cx), polygalacturonases (PG) and b-galactosidases. In peaches the AA- and N2-treated fruits were firmer after 3 weeks storage and contained higher amount of insoluble pectin than untreated controls. We showed that AA vapors are able to inhibit ripening, ethylene production and ethylene induction in the presence of 1-amino-cyclopropane-1-carboxylic acid (ADD) in avocado and mango tissue. Ethylene induced by ACC is taken as an indicator of ACC oxidase activity. ACC oxidase activity in AA-treated avocado fruit was much lower than in the untreated fruit. In carnation flowers very little ethylene was produced by ethanol-treated flowers, and the normal increases in ACC content and ACC oxidase activity were also suppressed. Using kinetic studies and inhibitors of alcohol dehydrogenase (ADH), we showed that AA, not ethanol, was the active molecule in inhibiting ripening of tomato fruit. Application of anaerobiosis or anaerobic metabolites was effective in reduction of chilling injury (CI) in various plant tissues. Pretreatment with a low-O2 atmosphere reduced CI symptoms in avocado; this effect was associated with higher content of the free sylfhydryl (SH) group, and induction of the detoxification enzymes, catalase and peroxidase. Application of AA maintained firmer and brighter pulp tissue (non-oxidative), which was associated with higher free SH content, lower ethylene and ACC oxidase activities, and higher activities of catalase and peroxidase. Ethanol was found to reduce CI in other plant tissue. In roots of 24-h-old germinated cucumber seeds, exposure to 0.4-M ethanol shock for 4 h reduced chilling-induced ion leakage. In cucumber cotyledons it appears that alcohols may reduce CI by inducing stomata closure. In cotyledon discs held in N2 at 10C for 1 day, there accumulated sufficient endogenously synthesized ethanol to confer tolerance to chilling at 2.5C for 5 days.
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Boisclair, Yves R., Alan W. Bell, and Avi Shamay. Regulation and Action of Leptin in Pregnant and Lactating Dairy Cows. United States Department of Agriculture, July 2000. http://dx.doi.org/10.32747/2000.7586465.bard.
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The original project had four specific objectives: (1) To complete the development of a radioimmunoassay for bovine leptin; (2) To characterize the leptin system in lactating dairy cows during the transition from pregnancy to lactation; (3) To identify endocrine factors regulating the production of leptin by bovine adipose tissue; (4) To study the actions of leptin on bovine adipose and mammary tissues in vitro. However, BARD funded only the development of the bovine leptin RIA (Objective 1) for a single year. This report describes our work in completing this objective. Leptin, a protein hormone secreted predominantly by white adipose tissue, plays a critical role in the regulation of energy metabolism. In rodents and humans, leptin informs the central nervous system of the size of the energy reserves, coordinates adaptations to periods of nutrient insufficiency, and regulates the metabolism of key tissues involved in the storage and dissipation of energy. However, almost nothing is known on the biology of leptin in cattle, in part because of the absence of a valid assay to measure bovine leptin. To remediate this situation, we have developed a radioimmunoassay capable of measuring bovine leptin with a high degree of sensitivity, accuracy and precision. First, we produced recombinant bovine leptin and used it to immunize rabbits, and to prepare bovine leptin trace and standards. A single antiserum with sufficient affinity and titer was identified. Using this antiserum, binding of 125I bovine leptin was displaced in a dose dependent manner by the addition of bovine or ovine leptin. Serial dilution of bovine and ovine plasma gave displacement curves that were parallel to that of bovine or ovine leptin. Recoveries of external addition of bovine leptin in ewe and cow plasma ranged between 94 and 104%. Plasma leptin concentration measured by this assay was increased by the plane of nutrition in growing calves and lambs. Finally, plasma leptin concentration was linearly related to the fat content of the empty carcass in growing cattle. We conclude that circulating leptin in sheep and cattle is increased by fatness and plane of nutrition, consistent with results in humans and rodents. This assay provides an important tool to investigate mechanisms that regulate plasma leptin in cattle and sheep.
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Friedman, Haya, Julia Vrebalov, and James Giovannoni. Elucidating the ripening signaling pathway in banana for improved fruit quality, shelf-life and food security. United States Department of Agriculture, October 2014. http://dx.doi.org/10.32747/2014.7594401.bard.
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Background : Banana being a monocot and having distinct peel and pulp tissues is unique among the fleshy fruits and hence can provide a more comprehensive understanding of fruit ripening. Our previous research which translated ripening discoveries from tomato, led to the identification of six banana fruit-associated MADS-box genes, and we confirmed the positive role of MaMADS1/2 in banana ripening. The overall goal was to further elucidate the banana ripening signaling pathway as mediated by MADS-boxtranscriptional regulators. Specific objectives were: 1) characterize transcriptional profiles and quality of MaMADS1/2 repressed fruit; 2) reveal the role of additional MaMADSgenes in ripening; 3) develop a model of fruit MaMADS-box mode of action; and 4) isolate new components of the banana ripening signaling pathway. Major conclusion: The functions of the banana MaMADS1-5 have been examined by complimenting the rinor the TAGL1-suppressed lines of tomato. Only MaMADS5 exhibited partial complementation of TAGL1-suppressed and rinlines, suggesting that while similar genes play corresponding roles in ripening, evolutionary divergence makes heterologous complementation studies challenging. Nevertheless, the partial complementation of tomato TAGL1-surpessed and rinlines with MaMADS5 suggests this gene is likely an important ripening regulator in banana, worthy of further study. RNA-seqtranscriptome analysis during ripening was performed on WT and MaMADS2-suppressed lines revealing additional candidate genes contributing to ripening control mechanisms. In summary, we discovered 39 MaMADS-box genes in addition to homologues of CNR, NOR and HB-1 expressed in banana fruits, and which were shown in tomato to play necessary roles in ripening. For most of these genes the expression in peel and pulp was similar. However, a number of key genes were differentially expressed between these tissues indicating that the regulatory components which are active in peel and pulp include both common and tissue-specific regulatory systems, a distinction as compared to the more uniform tomato fruit pericarp. Because plant hormones are well documented to affect fruit ripening, the expressions of genes within the auxin, gibberellin, abscisic acid, jasmonic acid, salicylic and ethylene signal transduction and synthesis pathways were targeted in our transcriptome analysis. Genes’ expression associated with these pathways generally declined during normal ripening in both peel and pulp, excluding cytokinin and ethylene, and this decline was delayed in MaMADS2-suppressed banana lines. Hence, we suggest that normal MaMADS2 activity promotes the observed downward expression within these non-ethylene pathways (especially in the pulp), thus enabling ripening progression. In contrast, the expressions of ACSand ACOof the ethylene biosynthesis pathway increase in peel and pulp during ripening and are delayed/inhibited in the transgenic bananas, explaining the reduced ethylene production of MaMADS2-suppressed lines. Inferred by the different genes’ expression in peel and pulp of the gibberellins, salicylic acid and cytokinins pathways, it is suggested that hormonal regulation in these tissues is diverse. These results provide important insights into possible avenues of ripening control in the diverse fruit tissues of banana which was not previously revealed in other ripening systems. As such, our transcriptome analysis of WT and ripening delayed banana mutants provides a starting point for further characterization of ripening. In this study we also developed novel evidence that the cytoskeleton may have a positive role in ripening as components of this pathway were down-regulated by MaMADS2 suppression. The mode of cytoskeleton involvement in fruit ripening remains unclear but presents a novel new frontier in ripening investigations. In summary, this project yielded functional understanding of the role and mode of action of MaMADS2 during ripening, pointing to both induction of ethylene and suppression of non-ethylene hormonal singling pathways. Furthermore, our data suggest important roles for cytoskeleton components and MaMADS5 in the overall banana ripening control network. Implications: The project revealed new molecular components/genes involved in banana ripening and refines our understanding of ripening responses in the peel and pulp tissues of this important species. This information is novel as compared to that derived from the more uniform carpel tissues of other highly studied ripening systems including tomato and grape. The work provides specific target genes for potential modification through genetic engineering or for exploration of useful genetic diversity in traditional breeding. The results from the project might point toward improved methods or new treatments to improve banana fruit storage and quality.
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Rafaeli, Ada, and Russell Jurenka. Molecular Characterization of PBAN G-protein Coupled Receptors in Moth Pest Species: Design of Antagonists. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7593390.bard.
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The proposed research was directed at determining the activation/binding domains and gene regulation of the PBAN-R’s thereby providing information for the design and screening of potential PBAN-R-blockers and to indicate possible ways of preventing the process from proceeding to its completion. Our specific aims included: (1) The identification of the PBAN-R binding domain by a combination of: (a) in silico modeling studies for identifying specific amino-acid side chains that are likely to be involved in binding PBAN with the receptor and; (b) bioassays to verify the modeling studies using mutant receptors, cell lines and pheromone glands (at tissue and organism levels) against selected, designed compounds to confirm if compounds are agonists or antagonists. (2) The elucidation ofthemolecular regulationmechanisms of PBAN-R by:(a) age-dependence of gene expression; (b) the effect of hormones and; (c) PBAN-R characterization in male hair-pencil complexes. Background to the topic Insects have several closely related G protein-coupled receptors (GPCRs) belonging to the pyrokinin/PBAN family, one with the ligand pheromone biosynthesis activating neuropeptide or pyrokinin-2 and another with diapause hormone or pyrokinin-1 as a ligand. We were unable to identify the diapause hormone receptor from Helicoverpa zea despite considerable effort. A third, related receptor is activated by a product of the capa gene, periviscerokinins. The pyrokinin/PBAN family of GPCRs and their ligands has been identified in various insects, such as Drosophila, several moth species, mosquitoes, Triboliumcastaneum, Apis mellifera, Nasoniavitripennis, and Acyrthosiphon pisum. Physiological functions of pyrokinin peptides include muscle contraction, whereas PBAN regulates pheromone production in moths plus other functions indicating the pleiotropic nature of these ligands. Based on the alignment of annotated genomic sequences, the primary and secondary structures of the pyrokinin/PBAN family of receptors have similarity with the corresponding structures of the capa or periviscerokinin receptors of insects and the neuromedin U receptors found in vertebrates. Major conclusions, solutions, achievements Evolutionary trace analysisof receptor extracellular domains exhibited several class-specific amino acid residues, which could indicate putative domains for activation of these receptors by ligand recognition and binding. Through site-directed point mutations, the 3rd extracellular domain of PBAN-R was shown to be critical for ligand selection. We identified three receptors that belong to the PBAN family of GPCRs and a partial sequence for the periviscerokinin receptor from the European corn borer, Ostrinianubilalis. Functional expression studies confirmed that only the C-variant of the PBAN-R is active. We identified a non-peptide agonist that will activate the PBAN-receptor from H. zea. We determined that there is transcriptional control of the PBAN-R in two moth species during the development of the pupa to adult, and we demonstrated that this transcriptional regulation is independent of juvenile hormone biosynthesis. This transcriptional control also occurs in male hair-pencil gland complexes of both moth species indicating a regulatory role for PBAN in males. Ultimate confirmation for PBAN's function in the male tissue was revealed through knockdown of the PBAN-R using RNAi-mediated gene-silencing. Implications, both scientific and agricultural The identification of a non-peptide agonist can be exploited in the future for the design of additional compounds that will activate the receptor and to elucidate the binding properties of this receptor. The increase in expression levels of the PBAN-R transcript was delineated to occur at a critical period of 5 hours post-eclosion and its regulation can now be studied. The mysterious role of PBAN in the males was elucidated by using a combination of physiological, biochemical and molecular genetics techniques.
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Matthews, Lisa, Guanming Wu, Robin Haw, Timothy Brunson, Nasim Sanati, Solomon Shorser, Deidre Beavers, Patrick Conley, Lincoln Stein, and Peter D'Eustachio. Illuminating Dark Proteins using Reactome Pathways. Reactome, October 2022. http://dx.doi.org/10.3180/poster/20221027matthews.
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Diseases are often the consequence of proteins or protein complexes that are non-functional or that function improperly. An active area of research has focused on the identification of molecules that can interact with defective proteins and restore their function. While 22% percent of human proteins are estimated to be druggable, less than fifteen percent are targeted by FDA-approved drugs, and the vast majority of untargeted proteins are understudied or so-called "dark" proteins. Elucidation of the function of these dark proteins, particularly those in commonly drug-targeted protein families, may offer therapeutic opportunities for many diseases. Reactome is the most comprehensive, open-access pathway knowledgebase covering 2585 pathways and including 14246 reactions, 11088 proteins, 13984 complexes, and 1093 drugs. Placing dark proteins in the context of Reactome pathways provides a framework of reference for these proteins facilitating the generation of hypotheses for experimental biologists to develop targeted experiments, unravel the potential functions of these proteins, and then design drugs to manipulate them. To this end, we have trained a random forest with 106 protein/gene pairwise features collected from multiple resources to predict functional interactions between dark proteins and proteins annotated in Reactome and then developed three scores to measure the interactions between dark proteins and Reactome pathways based on enrichment analysis and fuzzy logic simulations. Literature evidence via manual checking and systematic NLP-based analysis support predicted interacting pathways for dark proteins. To visualize dark proteins in the context of Reactome pathways, we have also developed a new website, idg.reactome.org, by extending the Reactome web application with new features illustrating these proteins together with tissue-specific protein and gene expression levels and drug interactions.
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Sisler, Edward C., Raphael Goren, and Akiva Apelbaum. Controlling Ethylene Responses in Horticultural Crops at the Receptor Level. United States Department of Agriculture, October 2001. http://dx.doi.org/10.32747/2001.7580668.bard.
Full textAbstract:
Ethylene is a plant hormone that controls many plant responses, such as growth, senescence, ripening, abscission and seed germination. Recently, 1-methy- cyclopropene (1-MCP), was shown to bind to ethylene receptor for a certain period of time and prevent ethylene action. The objectives of this research were to synthesize analogues of 1-MCP and test their potency to block the ethylene receptor and inhibit ethylene action. During the course of this project, procedures for synthesis and shipment of the cyclopropene compounds were developed as well assay procedures for each compound were worked out. Thirteen new compounds were synthesized. All of them are structural analogues of 1-MCP, with substitution in the 1-position and a side chain containing 2 to 10 carbons. After preliminary studies, nine promising compounds were selected for in-depth study. The potency of the compounds to inhibit ethylene action was tested on a wide scope of systems like: climacteric fruits (banana, avocado and tomato), the triple response (etiolated peas), and leaf abscission (citrus). As the putative inhibitors are suspected to compete for the site of binding and a competitive type of inhibition could be considered, a high concentration of ethylene (300 m1.L-1) was used to induce ripening and other physiological processes. The tests were conducted under extreme conditions which hasten ripening like treatment and storage at 22 to 25oC. There were fluctuations in the responses as related to the concentrations of the inhibitors. Some required much higher concentration to exert the same effect, while some, when applied at the same concentration, blocked the receptor for a longer period of time than the others. Some fruits and other plant organs responded differently to the same inhibitor, indicating differences in characteristics and availability of the ethylene receptors in the various tissues. The potency of the putative inhibitors was found to be greatly affected by their molecular structural and size. In addition, it was found that treatment with the inhibitor should be given before the onset of ethylene action In the case of fruit, treatment should be carried out before the pre-climacteric stage. Simultaneous treatment with ethylene and the inhibitors reduced the inhibitors' effect. The relationship between ethylene and the inhibitors is of a non-competitive nature. All the fruits treated with the putative inhibitors resumed normal ripening after recovery from the inhibition. This fact is of great importance when considering the inhibitors for practical use. The advantage of using inhibitors of ethylene action over inhibitors of ethylene production lies in the ability of the inhibitors of ethylene action to protect the tissue against both endogenous and exogenous ethylene, thus providing better overall protection. Our findings indicate that 1-MCP and its structural analogues are potent inhibitors of ethylene action capable of providing good protection against endogenous and exogenous ethylene. The fact that the compounds are in a gas phase and are non-phytotoxic, odorless and effective at minute concentrations, renders them promising candidates for commercial use. However, the development of water-soluble inhibitors will expand the potential use of the inhibitors in agriculture.
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Kanner, Joseph, Mark Richards, Ron Kohen, and Reed Jess. Improvement of quality and nutritional value of muscle foods. United States Department of Agriculture, December 2008. http://dx.doi.org/10.32747/2008.7591735.bard.
Full textAbstract:
Food is an essential to our existence but under certain conditions it could become the origin to the accumulative health damages. Technological processes as heating, chopping, mincing, grounding, promote the lipid oxidation process in muscle tissues and meat foodstuffs. Lipid oxidation occurred rapidly in turkey muscle, intermediate in duck, and slowest in chicken during frozen storage. Depletion of tocopherol during frozen storage was more rapid in turkey and duck compared to chicken. These processes developed from lipid peroxides produce many cytotoxic compounds including malondialdehyde (MDA). The muscle tissue is further oxidized in stomach conditions producing additional cytotoxic compounds. Oxidized lipids that are formed during digestion of a meal possess the potential to promote reactions that incur vascular diseases. A grape seed extract (1% of the meat weight) and butylated hydroxytoluene (0.2% of the lipid weight) were each effective at preventing formation of lipid oxidation products for 3 hours during co-incubation with cooked turkey meat in simulated gastric fluid (SGF). Polyphenols in the human diet, as an integral part of the meal prevent the generation and absorption of cytotoxic compounds and the destruction of essential nutrients, eg. antioxidants vitamins during the meal. Polyphenols act as antioxidants in the gastrointestinal tract; they scavenge free radicals and may interact with reactive carbonyls, enzymes and proteins. These all reactions results in decreasing the absorption of reactive carbonyls and possible other cytotoxic compounds into the plasma. Consumptions of diet high in fat and red meat are contributory risk factors partly due to an increase production of cytotoxic oxidized lipid products eg. MDA. However, the simultaneously consumption of polyphenols rich foods reduce these factors. Locating the biological site of action of polyphenols in the in the gastrointestinal tract may explain the paradox between the protective effect of a highly polyphenols rich diet and the low bioavailability of these molecules in human plasma. It may also explain the "French paradox" and the beneficial effect of Mediterranean and Japanese diets, in which food products with high antioxidants content such as polyphenols are consumed during the meal.
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Granot, David, and Noel Michelle Holbrook. Role of Fructokinases in the Development and Function of the Vascular System. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7592125.bard.
Full textAbstract:
Plant vascular tissues are superhighways whose development and function have profound implications for productivity, yield and stress response. Preliminary studies by the PI indicated that sugar metabolism mediated by fructokinases (FRKs) has a pronounced effect on the transport properties of the xylem. The goal of this research was to determine how the main fructokinase gene, FRK2, and the only plastidic fructokinase, FRK3, influence vascular development and physiology, emphasizing processes that occur at both the cellular and organismic level. We found that both genes are expressed in vascular tissues, but FRK3 is expressed primarily in vascular tissues of mature petioles. Vascular anatomy of plants with antisense suppression of FRK2 uncovered that FRK2 is necessary for xylem and phloem development, most likely due to its role in vascular cell-wall synthesis, and affects vascular development all over the plant. As a result, suppression of FRK2 reduced hydraulic conductivity of roots, stem and leaves and restricted sugar phloem transport. Vascular anatomy of plants with RNAi suppression of FRK3 uncovered that FRK3 is required for vascular development in mature petiole but its role is partially complemented by FRK2. Suppression of FRK3 combined with partial suppression of FRK2 had effects completely different from that of FRK2 suppression, resulting in wilting of mature leaves rather than young leaves of FRK2 suppressed plants, and decreased export of photoassimilates. This primary effect of FRK2 suppression on mature petioles had a secondary effect, reducing the hydraulic conductivity in roots and stem. The very fact that a plastidic fructokinase plays a role in vascular development is quite surprising and we are still seeking to uncover its metabolic mode-of-action. Yet, it is clear that these two fructokinases have different roles in the coordination between photosynthetic capacity and vascular development. We have started analyzing the role of the last third FRK, FRK1, and discovered that it is also expressed exclusively in vascular tissues. It appears therefore, that all FRKs studied here are involved in vascular development. An interesting unexpected outcome of this study was the connection of FRK2 with hormonal regulation of vascular development, most likely auxin. This observation together with the yet to be solved questions on the exact roles of FRK3 are the subjects of our current efforts.
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Eshed-Williams, Leor, and Daniel Zilberman. Genetic and cellular networks regulating cell fate at the shoot apical meristem. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7699862.bard.
Full textAbstract:
The shoot apical meristem establishes plant architecture by continuously producing new lateral organs such as leaves, axillary meristems and flowers throughout the plant life cycle. This unique capacity is achieved by a group of self-renewing pluripotent stem cells that give rise to founder cells, which can differentiate into multiple cell and tissue types in response to environmental and developmental cues. Cell fate specification at the shoot apical meristem is programmed primarily by transcription factors acting in a complex gene regulatory network. In this project we proposed to provide significant understanding of meristem maintenance and cell fate specification by studying four transcription factors acting at the meristem. Our original aim was to identify the direct target genes of WUS, STM, KNAT6 and CNA transcription factor in a genome wide scale and the manner by which they regulate their targets. Our goal was to integrate this data into a regulatory model of cell fate specification in the SAM and to identify key genes within the model for further study. We have generated transgenic plants carrying the four TF with two different tags and preformed chromatin Immunoprecipitation (ChIP) assay to identify the TF direct target genes. Due to unforeseen obstacles we have been delayed in achieving this aim but hope to accomplish it soon. Using the GR inducible system, genetic approach and transcriptome analysis [mRNA-seq] we provided a new look at meristem activity and its regulation of morphogenesis and phyllotaxy and propose a coherent framework for the role of many factors acting in meristem development and maintenance. We provided evidence for 3 different mechanisms for the regulation of WUS expression, DNA methylation, a second receptor pathway - the ERECTA receptor and the CNA TF that negatively regulates WUS expression in its own domain, the Organizing Center. We found that once the WUS expression level surpasses a certain threshold it alters cell identity at the periphery of the inflorescence meristem from floral meristem to carpel fate [FM]. When WUS expression highly elevated in the FM, the meristem turn into indeterminate. We showed that WUS activate cytokinine, inhibit auxin response and represses the genes required for root identity fate and that gradual increase in WUCHEL activity leads to gradual meristem enlargement that affect phyllotaxis. We also propose a model in which the direction of WUS domain expansion laterally or upward affects meristem structure differently. We preformed mRNA-seq on meristems with different size and structure followed by k-means clustering and identified groups of genes that are expressed in specific domains at the meristem. We will integrate this data with the ChIP-seq of the 4 TF to add another layer to the genetic network regulating meristem activity.
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Moza, Andreea, Florentina Duica, Panagiotis Antoniadis, Elena Silvia Bernad, Diana Lungeanu, Marius Craina, Brenda Cristiana Bernad, et al. Outcome of newborns in case of SARS-CoV-2 vertical infection. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, December 2022. http://dx.doi.org/10.37766/inplasy2022.12.0093.
Full textAbstract:
Review question / Objective: To identify the types and examine the range of available evidence of vertical transmission of SARS-CoV-2 from mother to newborn. To clarify the key concepts and criteria for diagnosis of SARS-CoV-2 vertical infection in neonates. To summarize the existing evidence and advance the awareness on SARS-CoV-2 vertical infection in pregnancy. Background: Severe Acute Respiratory Syndrome Virus 2 (SARS-CoV-2), the virus that causes 2019 coronavirus disease (COVID-19), has been isolated from various tissues and body fluids, including the placenta, amniotic fluid, and umbilical cord of newborns. In the last few years, much scientific effort has been directed towards studying SARS-CoV-2, focusing on the different features of the virus, such as its structure and mechanisms of action. Moreover, much focus has been on developing accurate diagnostic tools and various drugs or vaccines to treat COVID-19.