Academic literature on the topic 'Cellular control mechanisms – Mathematical models'
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Journal articles on the topic "Cellular control mechanisms – Mathematical models"
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Lomeli, Luis Martinez, Abdon Iniguez, Prasanthi Tata, Nilamani Jena, Zhong-Ying Liu, Richard Van Etten, Arthur D. Lander, Babak Shahbaba, John S. Lowengrub, and Vladimir N. Minin. "Optimal experimental design for mathematical models of haematopoiesis." Journal of The Royal Society Interface 18, no. 174 (January 2021): 20200729. http://dx.doi.org/10.1098/rsif.2020.0729.
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The haematopoietic system has a highly regulated and complex structure in which cells are organized to successfully create and maintain new blood cells. It is known that feedback regulation is crucial to tightly control this system, but the specific mechanisms by which control is exerted are not completely understood. In this work, we aim to uncover the underlying mechanisms in haematopoiesis by conducting perturbation experiments, where animal subjects are exposed to an external agent in order to observe the system response and evolution. We have developed a novel Bayesian hierarchical framework for optimal design of perturbation experiments and proper analysis of the data collected. We use a deterministic model that accounts for feedback and feedforward regulation on cell division rates and self-renewal probabilities. A significant obstacle is that the experimental data are not longitudinal, rather each data point corresponds to a different animal. We overcome this difficulty by modelling the unobserved cellular levels as latent variables. We then use principles of Bayesian experimental design to optimally distribute time points at which the haematopoietic cells are quantified. We evaluate our approach using synthetic and real experimental data and show that an optimal design can lead to better estimates of model parameters.
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Pedersen, Morten Gram, Gianna M. Toffolo, and Claudio Cobelli. "Cellular modeling: insight into oral minimal models of insulin secretion." American Journal of Physiology-Endocrinology and Metabolism 298, no. 3 (March 2010): E597—E601. http://dx.doi.org/10.1152/ajpendo.00670.2009.
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The oral glucose tolerance test and meal tolerance test are common clinical tests of the glucose-insulin system. Several mathematical models have been suggested as means to extract information about β-cell function from data from oral tolerance tests. Any such model needs to be fairly simple but should at the same time be linked to the underlying biology of the insulin-secreting β-cells. The scope of the present work is to present a way to make such a connection using a recent model describing intracellular mechanisms. We show how the three main components of oral minimal secretion models, derivative control, proportional control, and delay, are related to subcellular events, thus providing mechanistic underpinning of the assumptions of the minimal models.
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DRASDO, DIRK. "COARSE GRAINING IN SIMULATED CELL POPULATIONS." Advances in Complex Systems 08, no. 02n03 (June 2005): 319–63. http://dx.doi.org/10.1142/s0219525905000440.
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The main mechanisms that control the organization of multicellular tissues are still largely open. A commonly used tool to study basic control mechanisms are in vitro experiments in which the growth conditions can be widely varied. However, even in vitro experiments are not free from unknown or uncontrolled influences. One reason why mathematical models become more and more a popular complementary tool to experiments is that they permit the study of hypotheses free from unknown or uncontrolled influences that occur in experiments. Many model types have been considered so far to model multicellular organization ranging from detailed individual-cell based models with explicit representations of the cell shape to cellular automata models with no representation of cell shape, and continuum models, which consider a local density averaged over many individual cells. However, how the different model description may be linked, and, how a description on a coarser level may be constructed based on the knowledge of the finer, microscopic level, is still largely unknown. Here, we consider the example of monolayer growth in vitro to illustrate how, in a multi-step process starting from a single-cell based off-lattice-model that subsumes the information on the sub-cellular scale by characteristic cell-biophysical and cell-kinetic properties, a cellular automaton may be constructed whose rules have been chosen based on the findings in the off-lattice model. Finally, we use the cellular automaton model as a starting point to construct a multivariate master equation from a compartment approach from which a continuum model can be derived by a systematic coarse-graining procedure. We find that the resulting continuum equation largely captures the growth behavior of the CA model. The development of our models is guided by experimental observations on growing monolayers.
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Adams, DS. "Mechanisms of cell shape change: the cytomechanics of cellular response to chemical environment and mechanical loading." Journal of Cell Biology 117, no. 1 (April 1, 1992): 83–93. http://dx.doi.org/10.1083/jcb.117.1.83.
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Processes such as cell locomotion and morphogenesis depend on both the generation of force by cytoskeletal elements and the response of the cell to the resulting mechanical loads. Many widely accepted theoretical models of processes involving cell shape change are based on untested hypotheses about the interaction of these two components of cell shape change. I have quantified the mechanical responses of cytoplasm to various chemical environments and mechanical loading regimes to understand better the mechanisms of cell shape change and to address the validity of these models. Measurements of cell mechanical properties were made with strands of cytoplasm submerged in media containing detergent to permeabilize the plasma membrane, thus allowing control over intracellular milieu. Experiments were performed with equipment that generated sinusoidally varying length changes of isolated strands of cytoplasm from Physarum polycephalum. Results indicate that stiffness, elasticity, and viscosity of cytoplasm all increase with increasing concentration of Ca2+, Mg2+, and ATP, and decrease with increasing magnitude and rate of deformation. These results specifically challenge assumptions underlying mathematical models of morphogenetic events such as epithelial folding and cell division, and further suggest that gelation may depend on both actin cross-linking and actin polymerization.
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Edwards, Aurélie. "Modeling transport in the kidney: investigating function and dysfunction." American Journal of Physiology-Renal Physiology 298, no. 3 (March 2010): F475—F484. http://dx.doi.org/10.1152/ajprenal.00501.2009.
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Mathematical models of water and solute transport in the kidney have significantly expanded our understanding of renal function in both health and disease. This review describes recent theoretical developments and emphasizes the relevance of model findings to major unresolved questions and controversies. These include the fundamental processes by which urine is concentrated in the inner medulla, the ultrastructural basis of proteinuria, irregular flow oscillation patterns in spontaneously hypertensive rats, and the mechanisms underlying the hypotensive effects of thiazides. Macroscopic models of water, NaCl, and urea transport in populations of nephrons have served to test, confirm, or refute a number of hypotheses related to the urine concentrating mechanism. Other macroscopic models focus on the mechanisms, role, and irregularities of renal hemodynamic control and on the regulation of renal oxygenation. At the mesoscale, models of glomerular filtration have yielded significant insight into the ultrastructural basis underlying a number of disorders. At the cellular scale, models of epithelial solute transport and pericyte Ca2+ signaling are being used to elucidate transport pathways and the effects of hormones and drugs. Areas where further theoretical progress is conditional on experimental advances are also identified.
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Goryachev, Andrew B., and Marcin Leda. "Compete or Coexist? Why the Same Mechanisms of Symmetry Breaking Can Yield Distinct Outcomes." Cells 9, no. 9 (September 1, 2020): 2011. http://dx.doi.org/10.3390/cells9092011.
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Cellular morphogenesis is governed by the prepattern based on the symmetry-breaking emergence of dense protein clusters. Thus, a cluster of active GTPase Cdc42 marks the site of nascent bud in the baker’s yeast. An important biological question is which mechanisms control the number of pattern maxima (spots) and, thus, the number of nascent cellular structures. Distinct flavors of theoretical models seem to suggest different predictions. While the classical Turing scenario leads to an array of stably coexisting multiple structures, mass-conserved models predict formation of a single spot that emerges via the greedy competition between the pattern maxima for the common molecular resources. Both the outcome and the kinetics of this competition are of significant biological importance but remained poorly explored. Recent theoretical analyses largely addressed these questions, but their results have not yet been fully appreciated by the broad biological community. Keeping mathematical apparatus and jargon to the minimum, we review the main conclusions of these analyses with their biological implications in mind. Focusing on the specific example of pattern formation by small GTPases, we speculate on the features of the patterning mechanisms that bypass competition and favor formation of multiple coexisting structures and contrast them with those of the mechanisms that harness competition to form unique cellular structures.
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Tallarida, R. J. "Receptor discrimination and control of agonist-antagonist binding." American Journal of Physiology-Endocrinology and Metabolism 269, no. 2 (August 1, 1995): E379—E391. http://dx.doi.org/10.1152/ajpendo.1995.269.2.e379.
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The law of mass action is the common model for the interaction of agonist and antagonist compounds with cellular receptors. Parameters of the interaction, obtained from functional and radioligand-binding studies, allow discrimination and subtyping of receptors and aid in understanding specific mechanisms. This article reviews the theory and associated mathematical models and graphical transformations of data that underlie the determination of receptor parameters. The main theory assumes that agonist and antagonist compounds bind to cells that have a fixed number of receptors and provides the framework for obtaining drug-receptor parameters from data and their graphical transformations. Conditions that produce a change in receptor number, a newer concept in pharmacology, can have an important effect on the parameter values derived in the usual way. This review concludes with a discussion of the quantitative study of receptor-mediated feedback control of endogenous ligands, a very new topic with potentially important implications for understanding antagonist effectiveness, loss of control, and chaos in regulated mass action binding.
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Dawn Parente, Jacquelyn, Knut Möller, Sabine Hensler, Claudia Kühlbach, Margareta M. Mueller, Paola Belloni, and J. Geoffrey Chase. "Technical Support of Wound Healing Processes: Project Status." Current Directions in Biomedical Engineering 5, no. 1 (September 1, 2019): 521–23. http://dx.doi.org/10.1515/cdbme-2019-0131.
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AbstractThe optimized wound healing (OWID) project provides technical support of wound healing processes. Advanced biophysical treatment therapies using light (photobiomodulation), negative pressure wound therapy (NPWT), and electrical stimulation show biological effects. Specifically, a biphasic dose-response curve is observed where lower doses activate cells, while above a threshold, higher doses are inhibitory. However, no standard protocols and no multi-modal treatment studies determine specific therapy needs. The OWID project aims to develop a multi-modal treatment device and modelbased therapy for individualized wound healing. This work presents the OWID project status. Currently, a photobiomodulation prototype delivers red, green, and blue light ‘medicine’ at prescribed therapeutic ‘doses’. The calculation of incident light necessarily considers transmission properties of the intervening cell culture plate. Negative pressure wound therapy (NPWT) and electrical impedance tomography (EIT) hardware are being adapted for use in vitro. Development of mathematical models of wound healing and therapy control are supported by treatment experiment outcome measures conducted in a wounded 3D tissue model. Parameter sensitivity analysis conducted on an existing mathematical model of reepithelialization results in changing parameter values influencing cellular movement rates. Thus, the model is robust to fit model parameters to observed reepithelialization rates under treatment conditions impacting cellular activation, inhibition, and untreated controls. Developed image analysis techniques have not captured changes in wound area after photobiomodulation treatment experiments. Alternatively, EIT will be tested for wound area analysis. Additionally, live dyes will be introduced to non-invasively visualize the reepithelialization front on a smaller, cellular scale. Finally, an overall therapeutic feedback control model uses model reference adaptive control to incorporate the intrinsic biological reepithelialization mechanism, treatment loops, and treatment controller modulation at a wound state. Currently, the OWID project conducts photobiomodulation treatment experiments in vitro and has developed mathematical models. Future work includes the incorporation of multi-modal wound healing treatment experiments.
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Sánchez-Jiménez, F., R. Montañez, F. Correa-Fiz, P. Chaves, C. Rodríguez-Caso, J. L. Urdiales, J. F. Aldana, and M. A. Medina. "The usefulness of post-genomics tools for characterization of the amine cross-talk in mammalian cells." Biochemical Society Transactions 35, no. 2 (March 20, 2007): 381–85. http://dx.doi.org/10.1042/bst0350381.
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Evidence is growing in favour of a relationship between cancer and chronic inflammation, and particularly of the role of a polyamine and histamine metabolic interplay involved in these physiopathological problems, which are indeed highly complex biological systems. Decodification of the complex inter- and intra-cellular signalling mechanisms that control these effects is not an easy task, which must be helped by systems biology technologies, including new tools for location and integration of database-stored information and predictive mathematical models, as well as functional genomics and other experimental molecular approaches necessary for hypothesis validation. We review the state of the art and present our latest efforts in this area, focused on the amine metabolism field.
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Almeida, S., M. Chaves, and F. Delaunay. "Control of synchronization ratios in clock/cell cycle coupling by growth factors and glucocorticoids." Royal Society Open Science 7, no. 2 (February 2020): 192054. http://dx.doi.org/10.1098/rsos.192054.
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The cell cycle and the circadian clock are essential cyclic cellular processes often synchronous in healthy cells. In this work, we use previously developed mathematical models of the mammalian cell cycle and circadian cellular clock in order to investigate their dynamical interactions. Firstly, we study unidirectional cell cycle → clock coupling by proposing a mechanism of mitosis promoting factor (MPF)-controlled REV-ERB α degradation. Secondly, we analyse a bidirectional coupling configuration, where we add the CLOCK : BMAL1-mediated MPF repression via the WEE1 kinase to the first system. Our simulations reproduce ratios of clock to cell cycle period in agreement with experimental observations and give predictions of the system’s synchronization state response to a variety of control parameters. Specifically, growth factors accelerate the coupled oscillators and dexamethasone (Dex) drives the system from a 1 : 1 to a 3 : 2 synchronization state. Furthermore, simulations of a Dex pulse reveal that certain time regions of pulse application drive the system from 1 : 1 to 3 : 2 synchronization while others have no effect, revealing the existence of a responsive and an irresponsive system’s phase, a result we contextualize with observations on the segregation of Dex-treated cells into two populations.
Dissertations / Theses on the topic "Cellular control mechanisms – Mathematical models"
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Thomson, Susmita. "Local feedback regulation of salt & water transport across pumping epithelia : experimental & mathematical investigations in the isolated abdominal skin of Bufo marinus." University of Western Australia. Dept. of Physiology, 2003. http://theses.library.uwa.edu.au/adt-WU2003.0022.
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[Truncated abstract] This study describes the results of a four and a half year investigation examining local regulation of ion transport through pumping epithelial cells. The study focussed on the standard isolated toad skin preparation, made famous by Hans Ussing. Originally, the objective was to perform some simple manipulations on the isolated toad skin, a standard and well-tested epithelial layer, which, according to the literature, was a well-behaved and stable preparation. The purpose of doing these toad skin experiments was to gain familiarity with the experimental techniques, such as measuring the open-circuit voltage (Voc) and the short-circuit current (Isc) across an epithelium. In the process, the experimental information that was obtained was to assist in the development and refinement of a mathematical model of a single pumping epithelial cell . . . Finally, it should be emphasised the toad skin was a convenient tissue model for exploring more general issues such as: (i) how pumping epithelial cells may adjust to changes in the extracellular environment by locally regulating their membrane conductances; (2) how the topology of a cell can influence its function (i.e. the topology can determine whether a cell is optimised for salt transport or water transport). (3) how different cells, with different functions, may be positioned in apposition in a pumping epithelial tissue so that gradients generated by one cell type can be utilised by another. From a broader perspective, it is likely that such issues are also applicable to other pumping epithelia, and ultimately, may assist in understanding how these epithelia function.
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Schultz, Joshua Andrew. "Mathematical modeling and control of a piezoelectric cellular actuator exhibiting quantization and flexibility." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45776.
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This thesis presents mathematical modeling and control techniques that can be used to predict and specify performance of biologically inspired actuation systems called cellular actuators. Cellular actuators are modular units designed to be connected in bundles in manner similar to human muscle fibers. They are characterized by inherent compliance and large numbers of on-off discrete control inputs. In this thesis, mathematical tools are developed that connect the performance to the physical manifestation of the device. A camera positioner inspired by the human eye is designed to demonstrate how these tools can be used to create an actuator with a useful force-displacement characteristic. Finally, control architectures are presented that use discrete switching inputs to produce smooth motion of these systems despite an innate tendency toward oscillation. These are demonstrated in simulation and experiment.
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Thomson, Susmita. "Local feedback regulation of salt & water transport across pumping epithelia : experimental & mathematical investigations in the isolated abdominal skin of Bufo marinus /." Connect to this title, 2002. http://theses.library.uwa.edu.au/adt-WU2003.0022.
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Nilsson, Karin. "Intracellular regulation in bacteria : control of initiation of chromosome replication; macrolide antibiotics, resistance mechanisms and bi-stable growth rates /." Uppsala : Dept. of Biometry and Engineering, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200672.pdf.
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Conradie, Riaan. "A comparative analysis of the G1/S transition control in kinetic models of the eukaryotic cell cycle." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1236.
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Thesis (PhD (Biochemistry))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: The multiplication of cells proceeds through consecutive phases of growth and division (G1, S, G2 and M phases), in a process known as the cell cycle. The transition between these phases is regulated by so-called checkpoints, which are important to ensure proper functioning of the cell cycle. For instance, mutations leading to faulty regulation of the G1/S transition point are seen as one of the main causes of cancer. Traditionally, models for biological systems that show rich dynamic behavior, such as the cell cycle, are studied using dynamical systems analysis. However, using this analysis method one cannot quantify the extent of control of an individual process in the system. To understand system properties at the process level, one needs to employ methods such as metabolic control analysis (MCA). MCA was, however, developed for steady-state systems, and is thus limited to the analysis of such systems, unless the necessary extensions would be made to the framework. The central question of this thesis focuses on quantifying the control in mathematical models of the G1/S transition by the individual cell cycle processes. Since MCA was never applied to the cell cycle, several new methods needed to be added to the framework. The most important extension made it possible to follow and quantify, during a single cell cycle, the control properties of the individual system processes. Subsequently, these newly developed methods were used to determine the control by the individual processes of an important checkpoint in mammalian cells, the restriction point. The positioning of the restriction point in the cell cycle was distributed over numerous system processes, but the following processes carried most of the control: reactions involved in the interplay between retinoblastoma protein (Rb) and E2F transcription factor, reactions responsible for the synthesis of Delayed Response Genes and Cyclin D/Cdk4 in response to growth signals, the E2F dependent Cyclin E/Cdk2 synthesis reaction, as well as the reactions involved in p27 formation. In addition it was shown that these reactions exhibited their control on the restriction point via the Cyclin E/Cdk2/p27 complex. Any perturbation of the system leading to a change in the restriction point could be explained via its e ect on the Cyclin E/Cdk2/p27 complex, showing a causal relation between restriction point positioning and the concentration of the Cyclin E/Cdk2/p27 complex. Finally, we applied the new methods, with a modular approach, to compare a number of cell cycle models for Saccharomyces cerevisiae (budding yeast) and mammalian cells with respect to the existence of a mass checkpoint. Such a checkpoint ensures that cells would have a critical mass at the G1/S transition point. Indeed, in budding yeast, a correction mechanism was observed in the G1 phase, which stabilizes the size of cells at the G1/S transition point, irrespective of changes in the specific growth rate. This in contrast to the mammalian cell cycle models in which no such mass checkpoint could be observed in the G1 phase. In this thesis it is shown that by casting specific questions on the regulation and control of cell cycle transition points in the here extended framework of MCA, it is possible to derive consensus answers for subsets of mathematical models.
AFRIKAANSE OPSOMMING: Die selsiklus bestaan uit agtereenvolgende groei- en delingsiklusse wat tot selvermeerdering lei. Die siklus word gekenmerk deur onderskeie fases (G1, S, G2 en M) wat deur sogenaamde beheerpunte gereguleer word. Hierdie beheerpunte verseker dat selvermeerdering nie ongekontroleerd kan plaasvind nie en mutasies wat lei tot foutiewe regulering van die G1/S transisiepunt word as een van die hoofoorsake van kanker beskou. Die hoofdoel van hierdie studie was om die beheer wat selsiklusprosesse op die G1/S transisie uitoefen met behulp van wiskundige modelle te kwantifiseer. Omdat biologiese sisteme soos die selsiklus ryk dinamiese gedrag vertoon, word hulle tradisioneeldeur middel van dinamiese sisteemanalise bestudeer. Die analisemetode beskik egter nie oor die vermoë om die hoeveelheid beheer wat afsonderlike sisteemprosesse op 0n sisteemeienskap uitoefen te kwantifiseer nie. Om sisteemeienskappe op prosesvlak te verstaan moet metodes soos metaboliese kontrole analise (MKA) ingespan word. MKA was egter ontwikkel om sisteme in 0n bestendige toestand te analiseer en aangesien MKA nog nooit vantevore vir selsiklus analises gebruik was nie, moes nuwe MKA tegnieke gedurende die studie ontwikkel word. Die belangrikste van die metodes maak dit moontlik om beheer (soos uitgeoefen deur die onderskeie sisteemprosesse) oor 0n enkele selsiklus na te volg en te kwantifiseer. Die nuut-ontwikkelde metodes was vervolgens gebruik om te bepaal hoe een so 0n beheerpunt in soogdierselle - die restriksiepunt - deur die onderskeie sisteemprosesse beheer word. Die studie het aangedui dat die posisie van die restriksiepunt tydens die selsiklus deur ’n verskeidenheid sisteemprosesse beheer word. Die bevinding was dat vier prosesse beduidend meer beheer op die posisie van die restriksiepunt uitoefen: Reaksies wat betrekking het op die wisselwerking tussen retinoblastoma proteïen (Rb) en E2F transkripsiefaktor; reaksies verantwoordelik vir die sintese van vertraagde responsgene en Siklien D/Cdk4 in respons tot groeiseine; die E2F afhanklike Siklien E/Cdk2 sintesereaksie; sowel as die reaksies betrokke in p27 vorming. Daar was ook aangetoon dat hierdie reaksies hul beheer op die posisie van die restriksiepunt deur die Siklien E/Cdk2/p27 kompleks uitoefen, siende enige sisteemversteuringe (wat tot veranderinge in die restriksiepuntposisie aanleiding gee) deur veranderinge in die kompleks verklaar kon word - 0n observasie wat aandui dat daar 0n kousale verhouding is tussen die posisie van die restriksiepunt en die Siklien E/Cdk2/p27 kompleks. Die nuut-ontwikkelde metodes was verder gebruik om 0n verskeidenheid selsiklusmodelle van Saccharomyces cerevisiae (bakkersgis) en soogdierselle met 0n modulêre aanpak te vergelyk om te bepaal of daar 0n massa beheerpunt in beide soogdier- en bakkersgisselle bestaan. Daar word gepostuleer dat hierdie beheerpunt verseker dat selle 0n kritiese massa by die G1/S transisiepunt bereik. Die resultate van die studie dui daarop dat bakkersgis, anders as soogdierselle, oor so 0n korreksiemeganisme beskik. Die meganisme stabiliseer die grootte van selle in die G1 fase ondanks veranderinge in die groeitempo van die selle, sodat massa homeostaties by die G1/S transisiepunt gehandhaaf word. Die studie het getoon dat moeilike vrae met betrekking tot die selsiklus beantwoord kan word deur van wiskundige modelle gebruik te maak en die probleme in die nuut-ontwikkelde metaboliese kontrole analise raamwerk te giet.
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Campbell, Amanda Marie. "Investigation of the action of phosphatase of regenerating liver on PTEN using murine models." Thesis, 2014. http://hdl.handle.net/1805/6220.
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Indiana University-Purdue University Indianapolis (IUPUI)The addition and removal of phosphate groups is a key regulatory mechanism for many cellular processes. The balance between phosphorylation and dephosphorylation is delicate and must be maintained in order for proper cell functions to be carried out. Protein kinases and phosphatases are the keepers of this balance with kinases adding phosphate groups and phosphatases removing them. As such, mutation and/or altered regulation of these proteins can be the driving factor in disease. Phosphatase of Regenerating Liver (PRL) is a family novel of three dual specificity phosphatases (DSPs) first discovered in the regenerating liver tissue of rats. PRLs have also been shown to act as oncogenes in cell culture and in animal models. However, the physiological substrate and mechanisms of the PRLs are not yet known. Recently, our lab has developed a PRL 2 knockout mouse and found several striking phenotypes all of which correspond to a significant increase in PTEN. We also found that PRL 2 is targetable by small molecular inhibitors that can potentially be used to disrupt tumor growth and spermatogenesis. Furthermore, a PTEN heterozygous mouse model crossed into our PRL 2 knockout line was generated to investigate the relevance of PRL interaction with PTEN in cancer.
Books on the topic "Cellular control mechanisms – Mathematical models"
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Aguda, B. Models of cellular regulation. Oxford: Oxford University Press, 2008.
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P, Singh R. Organizational control mechanisms. New Delhi: Northern Book Centre, 1988.
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Heinrich, Reinhart. The regulation of cellular systems. New York: Chapman & Hall, 1996.
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service), SpringerLink (Online, ed. Introduction to Modeling Biological Cellular Control Systems. Milano: Springer Milan, 2012.
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Zhao, Jingshan. Ji qi ren ji gou zi you du fen xi li lun =: Analytical theory of degrees of freedom for robot mechanisms. Bei jing: Ke xue chu ban she, 2009.
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Hameroff, Stuart R. Ultimate computing: Biomolecular consciousness and nanotechnology. Amsterdam: North-Holland, 1987.
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Ultimatecomputing: Biomolecular consciousness and nano technology. Amsterdam: North-Holland, 1987.
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Committee on the Use of Animals in Research (U.S.), National Academy of Sciences (U.S.), and Institute of Medicine (U.S.), eds. Science, medicine, and animals. Washington, D.C: National Academy Press, 1991.
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Function and regulation of cellular systems. Basel: Birkhäuser Verlag, 2004.
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1960-, Deutsch Andreas, ed. Function and regulation of cellular systems. Basel: Birkhauser Verlag, 2004.
Find full textBook chapters on the topic "Cellular control mechanisms – Mathematical models"
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Knuesel, Jeremie, Jean-Marie Cabelguen, and Auke Ijspeert. "Decoding the Mechanisms of Gait Generation and Gait Transition in the Salamander Using Robots and Mathematical Models." In Motor Control, 417–46. Oxford University Press, 2010. http://dx.doi.org/10.1093/acprof:oso/9780195395273.003.0018.
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Duman, Ronald S. "Molecular and Cellular Pathogenesis of Depression and Mechanisms for Treatment Response." In Neurobiology of Mental Illness, edited by Helen S. Mayberg, 425–37. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199934959.003.0032.
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Early theories of depression were centered on the monoamines, but more recent work has focused on the amino acid neurotransmitters, glutamate and GABA. Imbalances of glutamate and GABA transmission in key cortical and limbic structures are thought to contribute to disruption of brain circuits that control emotion and mood. These imbalances, together with stress activated pathways that regulate neurotrophic factors and inflammatory cytokines could contribute to atrophy and loss of neurons observed in depressed patients and rodent stress models. The significance of synaptic connections in depression is highlighted by new studies demonstrating that a rapid acting, highly efficacious antidepressant agent increases synaptogenesis, paving the way for a new generation of medications for the treatment of depression.
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Ranganathan, Prakash, and Kendall Nygard. "Design Models for Resource Allocation in Cyber-Physical Energy Systems." In Sustainable ICTs and Management Systems for Green Computing, 111–30. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-4666-1839-8.ch005.
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Today’s and tomorrow’s smart grid systems are made more efficient, cleaner, and reliable by “smart” control mechanisms and decision models that deliver information to consumers so they can better manage energy resources. The rapidly changing needs and opportunities of today’s electric grid market require unprecedented levels of interoperability to integrate diverse information systems to share knowledge and collaborate among sub-devices or sub-systems in the grid. This book chapter focuses on optimal mathematical models for resource allocation. A series of mathematical models is presented in this book chapter for solving large-scale energy allocation problems with partially observable states, utility functions, and constrained action is introduced. The authors’ techniques use a Linear Programming (LP) approach to determine resource allocations among a set of fuzzy rules that allocates Distributed Energy Resources (DER’s) or power sources/sinks and uses to determine improving resource management.
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Monnot, Gwennaëlle C., and Pedro Romero. "Immunotherapy and tumour resistance to immune-mediated control and elimination." In Oxford Textbook of Cancer Biology, edited by Francesco Pezzella, Mahvash Tavassoli, and David J. Kerr, 423–37. Oxford University Press, 2019. http://dx.doi.org/10.1093/med/9780198779452.003.0029.
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The field of tumour immunology has gradually reached a consensus that the immune system and tumours sustain a rich set of dynamic interactions starting early during carcinogenesis. Incipient tumours may be eliminated by the immune system via adaptive immune responses mediated mainly by cytotoxic CD8 T lymphocytes, which recognize short antigenic peptides presented by polymorphic major histocompatibility complex (MHC) class I molecules. Advanced tumours, however, are generally highly resistant to the main effectors of the immune system. Moreover, the molecular and cellular composition of the tumour microenvironment is strongly immunosuppressive. Recent research efforts have focused on the dissection of the mechanisms operating at the tumour sites, which neutralize antitumour immunity in both experimental models and directly in cancer patients. All along this basic research, translational scientists have tried to harness the immune system to design novel therapeutic modalities that have collectively been coined as cancer immunotherapy. The overall goal has been to increase the numbers of tumour antigen-specific T cells in cancer patients via either vaccination or adoptive transfer of large numbers of immune cells. It is safe to state that cancer immunotherapy will provide a revolution in the treatment of cancer and the future may bear the prospect of effective tumour control in many cancer types, and that immunotherapy will be one of the main components of effective therapeutic options.
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Werner, Erika F., and Errol R. Norwitz. "Parturition." In Oxford Textbook of Endocrinology and Diabetes, 1287–98. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199235292.003.0905.
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Labour is the physiological process by which the products of conception are passed from the uterus to the outside world. Timely onset is the key determinant of perinatal outcome. Although all viviparous animals share this process, the molecular and cellular mechanisms appear to differ in humans. Most animal models have demonstrated that the fetus is in control of the timing of labour. However, the parturition cascade in humans appears to be autocrine/paracrine in nature, thus precluding direct investigation. This chapter summarizes the current knowledge on the biological mechanisms responsible for the onset of labour at term in the human, as well as reviewing the limited treatment options when these mechanisms falter.
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Alferov, G. V., G. G. Ivanov, P. A. Efimova, and A. S. Sharlay. "Stability of Linear Systems With Multitask Right-Hand Member." In Stochastic Methods for Estimation and Problem Solving in Engineering, 74–112. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-5045-7.ch004.
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To study the dynamics of mechanical systems and to define the construction parameters and control laws, it is necessary to have computational models accurately describing properties of real mechanisms. From a mathematical point of view, the computational models of mechanical systems are actually the systems of differential equations. These models can contain equations that also describe non-mechanical phenomena. In this chapter, the problems of stability and asymptotic stability conditions for the motion of mechanical systems with holonomic and non-holonomic constraints are under consideration. Stability analysis for the systems of differential equations is given in term of the second Lyapunov's method. With the use of the set-theoretic approach, the necessary and sufficient conditions for stability and asymptotic stability of zero solution of the considered system are formulated. The proposed approaches can be used to study the stability of the motion for robot manipulators, transport, space, and socio-economic systems.
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Ojha, Rudra Pratap, Pramod Kumar Srivastava, and Goutam Sanyal. "Pre-Vaccination and Quarantine Approach for Defense Against Worms Propagation of Malicious Objects in Wireless Sensor Networks." In Sensor Technology, 1233–51. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2454-1.ch059.
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Network security poses a challenge to wireless sensor networks (WSNs) achieving its true potential. It is hard to tackle due to operational constraints of networks. Worms have become an emergent threat to the wireless networks. The spread of worms in the network is epidemic in nature. This article proposes a novel mathematical model with pre-vaccination and quarantine for study of worm propagation dynamics in WSN that is based on epidemic model. Further, the authors have devised an expression to determine threshold communication radius and node density. The objective of this proposed model is to study the propagation dynamics of worms in wireless sensor networks. Through the model, investigate the stability condition of networks in the presence of malicious codes. The experimental studies indicate that the proposed model outperforms in terms of security and energy efficiency over other existing models. It is a leap toward worm-controlling mechanisms in sensor networks. Finally, the control mechanism and performance of the proposed model is validated through extensive simulation results.
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Bulatov, Vasily, and Wei Cai. "Introduction To Crystal Dislocations." In Computer Simulations of Dislocations. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780198526148.003.0004.
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Dislocations first appeared as an abstract mathematical concept. In the late 19th century, Italian mathematician Vito Volterra examined mathematical properties of singularities produced by cutting and shifting matter in a continuous solid body [1]. As happened to some other mathematical concepts, dislocations could have remained a curious product of mathematical imagination known only to a handful of devoted mathematicians. In 1934, however, three scientists, Taylor, Polanyi and Orowan, independently proposed that dislocations may be responsible for a crystal’s ability to deform plastically [2, 3, 4]. While successfully explaining most of the puzzling phenomenology of crystal plasticity, crystal dislocations still remained mostly a beautiful hypothesis until the late 1950s when first sightings of them were reported in transmission electron microscopy (TEM) experiments [5]. Since then, the ubiquity and importance of dislocations for crystal plasticity and numerous other aspects of material behavior have been regarded as firmly established as, say, the role of DNA in promulgating life. Dislocations define a great many properties of crystalline materials. In addition to a crystal’s ability to yield and flow under stress, dislocations also control other mechanical behaviors such as creep and fatigue, ductility and brittleness, indentation hardness and friction. Furthermore, dislocations affect how a crystal grows from solution, how a nuclear reactor wall material is damaged by radiation, and whether or not a semiconductor chip in an electronic device will function properly. It can take an entire book just to describe the various roles dislocations play in materials behavior. However, the focus of this book is on the various computational models that have been developed to study dislocations. This chapter is an introduction to the basics of dislocations, setting the stage for subsequent discussions of computational models and associated numerical issues. Like any other crystal defect, dislocations are best defined with respect to the host crystal structure. We begin our discussion by presenting in Section 1.1 the basic elements and common terminology used to describe perfect crystal structures. Section 1.2 introduces the dislocation as a defect in the crystal lattice and discusses some of its essential properties. Section 1.3 discusses forces on dislocations and atomistic mechanisms for dislocation motion.
Conference papers on the topic "Cellular control mechanisms – Mathematical models"
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Penninger, Charles L., Andrés Tovar, Glen L. Niebur, and John E. Renaud. "High Fidelity Computational Model of Bone Remodeling Cellular Mechanisms." In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19464.
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One of the most intriguing aspects of bone is its ability to grow, repair damage, adapt to mechanical loads, and maintain mineral homeostasis [1]. It is generally accepted that bone adaptation occurs in response to the mechanical demands of our daily activities; moreover, strain and microdamage have been implicated as potential stimuli that regulate bone remodeling [2]. Computational models have been used to simulate remodeling in an attempt to better understand the metabolic activities which possess the key information of how this process is carried out [3]. At present, the connection between the cellular activity of remodeling and the applied mechanical stimuli is not fully understood. Only a few mathematical models have been formulated to characterize the remolding process in terms of the cellular mechanisms that occur [4,5].
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Penninger, Charles L., Neal M. Patel, and Andrés Tovar. "A Novel HCA Framework for Simulating the Cellular Mechanisms of Bone Remodeling." In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70613.
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Each year, bone metabolic diseases affect millions of people of all ages, genders, and races. Common diseases such as osteopenia and osteoporosis result from the disruption of the bone remodeling process and can place an individual at a serious fracture risk. Bone remodeling is the complex process by which old bone is replaced with new tissue. This process occurs continuously in the body and is carried out by bone cells that are regulated by numerous metabolic and mechanical factors. The remodeling process provides for various functions such as adaptation to mechanical loading, damage repair, and mineral homeostasis. An improved understanding of this process is necessary to identify patients at risk of bone disease and to assess appropriate treatment protocols. High-fidelity computer models are needed to understand the complex interaction of all parameters involved in bone remodeling. The primary focus of this investigation is to present a new computational framework that utilizes mathematical rules to mechanistically model the cellular mechanisms involved in the bone remodeling process. The computational framework used in this research combines accepted biological principles, cellular-level rules in a cellular automaton framework, and finite-element analysis. This computational model is referred to as hybrid cellular automaton (HCA) model. The simulations obtained with the HCA model allow to predict time-dependent morphology variations at the tissue level as a result of biological changes at the cellular level.
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Smychkova, Anna, and Dmitry Zhukov. "Complex of Description Models for Analysis and Control Group Behavior Based on Stochastic Cellular Automata with Memory and Systems of Differential Kinetic Equations." In 2019 1st International Conference on Control Systems, Mathematical Modelling, Automation and Energy Efficiency (SUMMA). IEEE, 2019. http://dx.doi.org/10.1109/summa48161.2019.8947537.
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Mayalu, Michaëlle N., and H. Harry Asada. "Integrated Mechanistic-Empirical Modeling of Cellular Response Based on Intracellular Signaling Dynamics." In ASME 2013 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/dscc2013-3806.
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A hybrid modeling framework integrating a highly specific mechanistic model with highly abstract empirical model is presented. With the growing interest in the scientific and medical community for identification of therapeutic targets in treatment of disease, it is necessary to develop predictive models that can describe cellular behavior in response to environmental cues. Intracellular signaling pathways form complex networks that regulate cellular response in both health and disease. Mechanistic (or white-box) models of biochemical networks are often unable to explain comprehensive cellular response due to lack of knowledge and/or intractable complexity (especially in events distal from the cell membrane). Empirical (or black-box) models may provide a less than accurate representation of cellular response due to data deficiency and/or loss of mechanistic detail. In the proposed framework, we use a mechanistic model to capture early signaling events and apply the resulting generated internal signals (along with external inputs) to a downstream empirical sub-model. The key construct in the approach is the treatment of a cell’s biochemical network as an encoder that creates a functional internal representation of external environmental cues. The signals derived from this representation are then used to inform downstream behaviors. Using this idea, we are able to create a comprehensive framework that describes important mechanisms with sufficient detail, while representing complex or unknown mechanisms in a more abstract form. The model is verified using published biological data describing T-Cells in immune response.
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Khulief, Y. A., and F. A. Al-Sulaiman. "Experimentally-Tuned Mathematical Model for Drillstring Vibrations." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-35057.
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Field experience manifests that drillstring vibration is one of the major causes for a deteriorated drilling performance. It is crucial to understand the complex vibrational mechanisms experienced by a drilling system in order to better control its functional operation and improve its performance. Experimental studies of drillstring dynamics are essential to complement the theoretical studies, and to alleviate the complexity of such dynamic models. This paper presents an experimental investigation using a specially designed drilling test rig. The test rig can simulate the drillstring vibrational response due to various excitation mechanisms, which include stick-slip, well-borehole contact, and drilling fluid interaction. The test rig is driven by a variable speed motor which allows for testing different drilling speeds, while a magnetic tension brake is used to simulated stick-slip. In addition, a shaker is employed to excite the drillstring axially in order to simulate the weight-on-bit (WOB). The drillstring is instrumented for vibration measurements. The experimentally identified parameters are used to refine the finite element multibody model of the drillstring, which was derived earlier by the investigators [1]. Comparisons with published data demonstrate the reliability of the developed scheme for prediction of drillstring vibrations.
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Wagner, John, Cecil Huey, and Katie Knaub. "Clock Mechanism Fundamentals for Education: Modeling and Analysis." In ASME 2008 Dynamic Systems and Control Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/dscc2008-2100.
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Time keeping devices have been designed, fabricated, and widely deployed throughout history to regulate daily functions including commerce and transportation. In addition, horology offers a catalog of mankind’s innovation and demonstrates important scientific and engineering concepts. The investigation and analysis of clock systems from a mechatronics perspective illustrates the evolution of gear systems, feedback control, and transformation of energy for time measurement. In this paper, the operational behavior of an eight day mechanical clock has been studied through mathematical models, numerical simulation, and computer animation. The classroom exploration of time keeping mechanisms offers practical applications of physical principles.
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Farahat, Waleed A., and H. Harry Asada. "Control of Eukaryotic Cell Migration Through Modulation of Extracellular Chemoattractant Gradients." In ASME 2010 Dynamic Systems and Control Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/dscc2010-4190.
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Cell migration is fundamental to a wide range of biological and physiological functions including: wound healing, immune defense, cancer metastasis, as well as the formation and development of biological structures such as vascular and neural networks. In these diverse processes, cell migration is influenced by a broad set of external mechanical and biochemical cues, particularly the presence of (time dependent) spatial gradients of soluble chemoattractants in the extracellular domain. Many biological models have been proposed to explain the mechanisms leading to the migratory response of cells as a function of these external cues. Based on such models, here we propose approaches to controlling the chemotactic response of eukaryotic cells by modulating their micro-environments in vitro (for example, using a microfluidic chemotaxis chamber). By explicitly modeling i) chemoattractant-receptor binding kinetics, ii) diffusion dynamics in the extracellular domain, and iii) the chemotactic response of cells, models for the migration processes arise. Based on those models, optimal control formulations are derived. We present simulation results, and suggest experimental approaches to controlling cellular motility in vitro, which can be used as a basis for cellular manipulation and control.
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Celik, Ismail B., Asaf Varol, Coskun Bayrak, and Jagannath R. Nanduri. "A One Dimensional Mathematical Model for Urodynamics." In ASME/JSME 2007 5th Joint Fluids Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/fedsm2007-37647.
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Millions of people in the world suffer from urinary incontinence and overactive bladder with the major causes for the symptoms being stress, urge, overflow and functional incontinence. For a more effective treatment of these ailments, a detailed understanding of the urinary flow dynamics is required. This challenging task is not easy to achieve due to the complexity of the problem and the lack of tools to study the underlying mechanisms of the urination process. Theoretical models can help find a better solution for the various disorders of the lower urinary tract, including urinary incontinence, through simulating the interaction between various components involved in the continence mechanism. Using a lumped parameter analysis, a one-dimensional, transient mathematical model was built to simulate a complete cycle of filling and voiding of the bladder. Both the voluntary and involuntary contraction of the bladder walls is modeled along with the transient response of both the internal and external sphincters which dynamically control the urination process. The model also includes the effects signals from the bladder outlet (urethral sphincter, pelvic floor muscles and fascia), the muscles involved in evacuation of the urinary bladder (detrusor muscle) as well as the abdominal wall musculature. The necessary geometrical parameters of the urodynamics model were obtained from the 3D visualization data based on the visible human project. Preliminary results show good agreement with the experimental results found in the literature. The current model could be used as a diagnostic tool for detecting incontinence and simulating possible scenarios for the circumstances leading to incontinence.
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Bayly, Philip V., and Kate S. Wilson. "Unstable Oscillations and Wave Propagation in Flagella." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-46920.
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Flagella are active, beam-like, sub-cellular organelles that use wavelike oscillations to propel the cell. The mechanisms underlying the coordinated beating of flagella remain incompletely understood despite the fundamental importance of these organelles. The axoneme (the cytoskeletal structure of flagella) consists of microtubule doublets connected by passive and active elements. The motor protein dynein is known to drive active bending, but dynein activity must be regulated to generate oscillatory, propulsive waveforms. Mathematical models of flagella motion generate quantitative predictions that can be analyzed to test hypotheses concerning dynein regulation. Here we investigate the emergence of unstable modes in a mathematical model of flagella motion with feedback from inter-doublet separation (the “geometric clutch” or GC model). The unstable modes predicted by the model may be used to critically evaluate the underlying hypothesis. The least stable mode of the GC model exhibits switching at the base and robust base-to-tip propagation.
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Xydas, Evagoras G., Loucas S. Louca, and Andreas Mueller. "Analysis and Passive Control of a Four-Bar Linkage for the Rehabilitation of Upper-Limb Motion." In ASME 2015 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/dscc2015-9916.
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In the last two decades robotic rehabilitation research provided significant insight regarding the human-robot interaction, helped understand the process by which the impaired nervous system is retrained to better control movements, and led to the development of a number of mathematical and neurophysiological models that describe both the human motion and the robot control. The human-machine interaction in this research is typically achieved through robotic devices that are based on open kinematic chains. These devices have multiple degrees of freedom (DOF), sophisticated computer control, actuation and sensing. The flexibility of such approach enables the easy implementation of the various models and methods that have to be applied in order to maximize the potential of robotic rehabilitation. On the other hand, mechanisms with fewer DOF’s that are based on closed kinematic chains can generate specific, yet adequate trajectories for the purposes of robotic rehabilitation. An example of such mechanisms is four-bar linkages that have only 1-DOF but yet can generate paths with complex kinematic characteristics. Design and analysis of four-bar linkages is used to achieve a variety of kinematics in terms of trajectory, velocity and acceleration profiles. The simplicity of these mechanisms is appealing and they can be used in rehabilitation due to their ability to replicate the motion of various human joints and limbs. The focus of the current work is to study the use of a four-bar linkage for generating the natural motion of upper-limb reaching tasks with the intention of using this mechanism for rehabilitation. This natural hand motion is described by a straight-line trajectory with a smooth bellshaped velocity profile, which in turn is generated by the well-established Minimum Jerk Model (MJM). The goal is to design passive control elements in a four-bar linkage that generate the required torque for producing the MJM motion. The passive elements are two linear translational springs that act on the driving link of a straight line generating mechanism. A design optimization is used to minimize the difference between the desired and actual input spring torque while remaining within the predefined design space. The final arrangement is simulated in a Multibody Dynamics software that applies feed-forward dynamics to generate the mechanism’s free response to the torque generated by the designed linear springs. The results of this work suggest that systematic design of a four-bar linkage can lead to simple mechanisms that can replicate the natural motion of reaching tasks. Relatively inexpensive linear springs can be employed in the design of passive-active controlled therapeutic mechanisms. Further investigation that combines analysis of both active and passive control/actuation elements must be performed for finalizing the control design. Simulations and analysis that incorporate various impaired hand responses must be also performed in order to finalize the design.