Dissertations / Theses on the topic 'Systems physiology'
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Santin, Joseph M. "Context-dependence of physiological systems: environment-physiology interactions in the respiratory control system." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright149336916471128.
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Christensen, Heather R. "Molecular and Integrated Systems Physiology of Prolactin." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1314040076.
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Butler, Jamie Andrew. "Data-based mechanistic modelling of systems in plant physiology." Thesis, Lancaster University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369469.
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Healey, Jennifer Anne. "Wearable and automotive systems for affect recognition from physiology." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9067.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 152-158).
Novel systems and algorithms have been designed and built to recognize affective patterns in physiological signals. Experiments were conducted for evaluation of the new systems and algorithms in three types of settings: a highly constrained laboratory setting, a largely unconstrained ambulatory environment, and a less unconstrained automotive environment. The laboratory experiment was designed to test for the presence of unique physiological patterns in each of eight different emotions given a relatively motionless seated subject, intentionally feeling and expressing these states. This experiment generated a large dataset of physiological signals containing many day-to-day variations, and the proposed features contributed to a success rate of 81% for discriminating all eight emotions and rates of up to 100% for subsets of emotion based on similar emotion qualities. New wearable computer systems and sensors were developed and tested on subjects who walked, jogged, talked, and otherwise went about daily activities. Although in the unconstrained ambulatory setting, physical motion often overwhelmed affective signals, the systems developed in this thesis are currently useful as activity monitors, providing an image diary correlated with physiological signals. Automotive systems were used to detect physiological stress during the natural but physically driving task. This generated a large database of physiological signals covering over 36 hours of driving. Algorithms for detecting driver stress achieved a recognition rates of 96% using stress ratings based on task conditions for validation and 89% accuracy using questionnaires analysis for validation. Further results in which metrics of stress from video tape annotations of the drive were correlated with physiological features showed highly significant correlations (up to r = .77 for over 4000 samples). Together, these three experiments show a range of success in recognizing affect from physiology, showing high recognition rates in somewhat constrained conditions and highlighting the need for more automatic context sensing in unconmore automatic context sensing in unconstrained conditions. The recognition rates obtained thus far lend support to the hypothesis that many emotional differences can be automatically discriminated in patterns of physiological changes.
by Jennifer A. Healey.
Ph.D.
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Rees, J. A. "Studies on adhesive gland systems in monogeneans." Thesis, University of East Anglia, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372362.
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Long, Lu. "The Anglo-tensin and endothelin systems in hypoxia-induced pulmonary hypertension." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312091.
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Du, Beau Amy. "Neurotransmitter phenotypes of descending systems in the rat lumbar spinal cord." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4721/.
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Sensorimotor processes within the spinal cord are profoundly influenced by descending systems from the brain yet the neurotransmitter phenotypes of these systems remains enigmatic. Using tract tracing methods, this study identifies the neurochemical content of axons descending from the sensorimotor cortex and sites within the anatomically diverse reticular formation. There are several classes of neurons in spinal lumbar segments targeted by these descending systems which contribute to recruiting adaptively appropriate motor patterns. This study investigates the neuronal targets of descending systems and the neurochemical content of their inputs. Immunofluorescent tissue containing labelled neuronal processes were examined and reconstructed interneurons were defined according to their neuronal geometry and morphology across laminar boundaries.
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Knight, Anthony. "A systems pharmacology approach to the adenosine A1 receptor." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/75201/.
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The majority of drugs are prescribed on the premise that their desired and undesired effects are well characterised. However, the mechanisms underlying these effects can be elusive and are of interest to the pharmaceutical industry in terms of rational drug design. G protein-coupled receptors are a significant class of drug target that are capable of influencing multiple signalling processes, and downstream effects, simultaneously through a variety of effectors, such as G proteins or –β-arrestins. The effector activated by a given receptor is often a function of the ligand. This is termed functional selectivity and can contribute to adverse drug effects. Understanding functional selectivity in a mammalian setting is hindered by cross-talk between many competing signalling components. The Sc. cerevisiae pheromone response can be modified to isolate individual mammalian receptor- G protein interactions. Therefore, this simple organism represents an excellent tool to study functional selectivity. Further, the simplicity of this organism allows this pathway to be mathematically modelled. By applying mathematical models to mammalian GPCR signalling in yeast it is possible to extract experimentally inaccessible quantitative parameters underlying functional selectivity. This interdisciplinary approach to pharmacological mechanisms is an example of systems pharmacology. Here a systems pharmacology approach is applied to adenosine receptor signalling in yeast with a view to understanding the contribution of the ligand, receptor and G protein to functional selectivity. The first stage of this process was expression and characterisation of adenosine A1R, A2AR, A2BR and A3R subtypes in yeast. Here, the A1R and A2R subtypes were shown to be functional in yeast, but the A3R response was limited. The A1R signals through G proteins representing the inhibitory G αi family in yeast, while the A2AR and A2BR signal through both inhibitory and stimulatory G protein equivalents. Here ligand bias is quantified but further extended to describe adenosine receptor selectivity. Further, the yeast system was used to inform novel fluorescent compound development. Fluorescent ligand-binding rates would ultimately inform modelling studies. A minimal mathematical framework was developed to described A1R signalling in yeast. Ordinary differential equation models recreate dynamic cellular processes. Here an ODE model was applied to experimental time course data to predict rate constants throughout the yeast G protein cycle in the presence of the mammalian A1R. This model predicts that G protein subtype influences the ligand-receptor-G protein interactions of the A1R in yeast. Further modification of the system and fluorescent technologies may help validate these predictions.
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Ashrafian, Hutan. "Global bio-systems modulation and the translational metabolic physiology of bariatric surgery." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/25304.
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The global pandemic of obesity continues to escalate worldwide and results in severe multisystem metabolic dysfunction in the expanding population of its sufferers. It is associated with the concurrent pathologies of type 2 diabetes, cardiovascular disease, cancer and sleep apnea, which have also increased in prevalence over the past decade. Obesity can be mapped in social networks and is recognised as a fundamental element of the metabolic syndrome contributing to the global burden of diabesity and oncobesity. Its impact on global health has resulted in a massive burden on healthcare services and is among the most prominent contributors to mounting healthcare costs. Despite its pathological impact, the non-surgical management of obesity through behavioural, lifestyle and pharmacotherapies has not offered dependable benefits in severely obese patients. Bariatric surgery has demonstrated consistent weight loss in morbidly obese subjects and is increasingly performed worldwide to treat morbid obesity. Furthermore, these operations may produce beneficial metabolic effects especially with respect to improvement in type 2 diabetes and the metabolic syndrome. Understanding surgical weight loss mechanisms and metabolic modulation is required to enhance patient benefits and operative outcomes. A surgical model of Roux-en-Y gastric bypass (RYGB) was developed as an experimental platform to investigate the metabolic effects of bariatric surgery. The model was studied through a systems biology approach to characterize systemic and gastro-intestinal surgical metabolic modulation. Analysis of postoperative faecal samples from this rodent model revealed a powerful shift in gut microbial ecology and also highlighted the role of RYGB surgery in regulating the cross-talk between the gut microbiome and its mammalian host. Similar metabolic changes were also identified in human subjects undergoing bariatric surgery. Analysis of plasma and cardiac tissue revealed shifts in metabolic activity, reflected by enhanced cardiac energy metabolism. Overall, the results of this work identify some of the potential mechanisms behind bariatric surgical weight loss and systemic metabolic enhancement. This study not only supports the term metabolic surgery but also identifies the global multi-systemic benefits of bariatric surgical procedures. As such, the findings presented in this thesis may in future contribute to the enhancement of current bariatric procedures and the development of the next-generation of innovative metabolic therapies.
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Bierbower, Sonya M. "ENVIRONMENTAL EFFECTS ON BEHAVIOR AND PHYSIOLOGY IN CRAYFISH." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/778.
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Despite dramatic morphological differences between animals from different taxa, several important features in organization and sensory system processing are similar across animals. Because of this similarity, a number of different organisms including mammals, insects, and decapod crustaceans serve as valuable model systems for understanding general principles of environmental effects. This research examines intrinsic and extrinsic factors by behaviorally and physiologically means to identify the impact of environmental conditions on two distinct crayfish species- Procambarus clarkii (surface) and Orconectes australis packardi (cave).
The research identified behavioral and physiological responses in these two morphological and genetically distinct species. The studies also examined multiple levels of complexity including social behavior, an autonomic response, chemosensory capabilities and neuronal communication, identified comparative similarities/differences, addressed learning and environmental influences on learning and examined behavioral and cellular responses to high levels of carbon dioxide. I found environmental factors directly influence crayfish behavior of social interactions. Interactions were more aggressive, more intense and more likely to end with a physical confrontation when they took place 'in water' than 'out of water'. The modified social interaction resulted in a altered fighting strategy.
A study on motor task learning was undertaken which showed similar learning trends among these crayfish species despite their reliance on different sensory modalities. I also demonstrated learning was dependent on perceived stress by the organism. Previously trained crayfish inhibited from completing a task showed significant increase in an autonomic stress response.
Studies on the behavioral and physiological responses to CO2 revealed that high [CO2] is a repellent in a concentration dependent manner. The autonomic responses in heart rate and an escape tailflip reflex shows complete cessation with high [CO2]. A mechanistic effect of CO2 is by blocking glutamate receptors at the neuromuscular junction and through inhibition of the motor nerve within the CNS.
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Bergman, Esbjörn. "Changes in sensory systems during aging : an experimental study in the rat /." Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3900-4/.
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Harrigan, Paul Richard. "Factors influencing the stability of dehydrated liposomal systems." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26416.
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Plant seeds, yeasts, bacterial spores, rotifers, and other organisms are capable of suspending their metabolism and entering a state of latency when dehydrated. These organisms may maintain this state for extremely long periods of time, yet upon rehydration resume normal metabolism, without evidence of severe membrane disruption. With many of these organisms, the ability to survive dehydration has been correlated to the production of large amounts of carbohydrates, including glycerol, glycogen and the disaccharide trehalose. Trehalose has been shown to protect isolated sarcoplasmic reticulum microsomes and phospholipid vesicles from dehydration damage, implying that the site of protective action of trehalose and other carbohydrates is the lipid portion of membranes. In this thesis, the effects of carbohydrate composition, vesicle size, and lipid composition on the protection of liposomes from dehydration was investigated, as was the structure of the solid lipid-trehalose complex. Electron microscopy of dried liposomes indicated that vesicles protected with trehalose remain essentially intact even when dry, while vesicles not protected by sugar are severely disrupted by drying . ³¹-P and ¹³-C NMR results suggested that the lipid of protected vesicles is in a similar phase as that of unprotected vesicles, and that this state is similar to powdered anhydrous phospholipid. Using carboxyfluorescein as a probe, it was demonstrated that trehalose, other sugars can prevent vesicle disruption upon dehydration. Different lipid compositions of the liposomes showed nearly identical behavior, with the exception of vesicles composed of dipalmitoylphosphatidylcholine and egg phosphatidylcholine, which showed greater and lower stability to dehydration respectively. Light scattering experiments indicated that a wide variety of carbohydrate and lipid vesicle combinations can withstand dehydration and maintain their original size when protected by sugars. The implications of these results in the development of liposomes as pharmaceuticals are discussed, and a hypothesis is advanced regarding the role of carbohydrates in the preservation of dry lipid membranes.Medicine, Faculty of
Biochemistry and Molecular Biology, Department of
Graduate
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Schmitt, Daniel T. "Time series analysis of real-world complex systems - climate, finance, proteins, and physiology." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-60656.
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Chintapalli, Venkateswara Rao. "An integrative and systems biology approach to Drosophila melanogaster transcriptomes." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3361/.
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The availability of fully sequenced genomes of the model organisms including Drosophila, and their subsequent annotation has afforded seamless opportunities for reverse genetics in a complex model organism. With the advent of DNA microarrays to assay the levels of tens of thousands of genes in a single sample, functional genomics has been significantly aided to understand the functions in systems context. These microarrays have been employed predominantly on the RNA samples that are extracted from the whole animals for example at different developmental stages or in response to external stimuli. However, these approaches relied on the expression patterns that represent the sum of transcription coming from all the organs, which do not estimate the tissue-specificity of transcription. The purpose of this thesis is to provide tissue-specific transcriptomes of Drosophila melanogaster that were generated as part of the large FlyAtlas project using Affymetrix Drosophila GeneChips® (or microarrays). These chips, one at a time interrogate the levels of 18,500 transcripts (that represent all known genes) using 18,880 distinct probe sets in a single, total RNA sample. For each tissue, four biological replicates were analysed using the chips and the normalised signal intensities were obtained that represent the relative levels of mRNA expression. Using the transcriptomes, a general analysis was performed for potential novel insights into tissue-specific functions (Chintapalli et al., 2007) (Chapter 3). Then, a comparative analysis of epithelial tissues was performed to understand how the epithelia are organised in terms of their transcriptomes (Chapter 4). The Malpighian tubules are the Drosophila epithelial counterparts of the human kidney. They show asymmetric organisation in the body cavity. FlyAtlas segment-specific tubule transcriptomes allowed the comparison of their potential functional similarities and differences, thus to understand the asymmetry in function (Chapter 5)(Chintapalli, 2012). This identified a human Best vitelliform macular dystrophy (BVMD) disease homolog, Best2 in only the anterior pair of tubules that have the morphologically and functionally distinct enlarged initial (or distal) segment, a storage organ for Ca2+. Bestrophins were accordingly selected as candidate genes to analyse organismal functions, and thus to validate previous two theories that implicated bestrophins as Ca2+-activated Clˉ channels and/or Ca2+ channel regulators (Chapter 6). The confocal microscopy analysis of bestrophin YFP fusion proteins revealed interesting and novel localisations of bestrophins, in that Best1 was found in the apical plasma membranes, Best2 localised to peroxisomes, Best3 and Best4 were found intracellular. The salt survival analysis showed that Best1 is essential in regulating extra salt levels in the body. Furthermore, the fluid secretion analysis showed Best1’s potential role in Ca2+-dependent Clˉ function. Interestingly, the flies with reduced levels of Best2 expression showed increased ability to survive on extra salt food; the basis for this was investigated further in Chapter 7. Best2 was also found abundant in the eyes than anywhere else in the head. A comparative analysis of anterior tubule- and eye-specific transcriptomes revealed a potential overlap of Ca2+ signaling components, in that the PLCβ signaling was one. A neuropeptide Ca2+ agonist, capa1 evoked secondary cytosolic Ca2+ responses were found high in Best2 knockdowns. A quantitative PCR (qPCR) analysis of candidate Ca2+ signaling and homeostasis genes in Best2 mutants revealed their gene expression upregulation, under control-fed and salt-fed conditions than their wildtype controls, fed on similar diet regimes. The norpA that encodes PLCβ was found significantly enriched in the mutants. Cyp6a23 is another gene that was highly upregulated in Best2 mutants; it is a Drosophila homologue of human Cyp11b, a Ca2+-responsive gene implicated in renal salt wasting. Upon the downregulation of Cyp6a23, flies became sensitive to salt diet feeding. Other genes investigated and found to be upregulated in the mutants include transient-receptor-potential (trp) Ca2+ channel and retinal degeneration C (rdgC). Together, these results strongly suggest Best2 as a potential Ca2+ channel regulator, and provide fascinating insight into bestrophin function. Peroxisomal localisation of Best2 in line with the implication that peroxisomes act as dynamic regulators of cell Ca2+ homeostasis led to another aspect of the project (Chapter 8). This study identified two peroxins that are most abundant in the tubules and play essential roles in the novel cyclic nucleotide-regulated peroxisomal Ca2+ sequestration and transport pathway and that are detrimental for peroxisome biogenesis and proliferation.
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Croft, Wayne D. "A systems and molecular analysis of G protein-mediated signalling." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/49621/.
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The ability of cells to respond correctly to signals from their microenvironment is an essential prerequisite of life. Many external signals are detected through G protein-coupled receptor (GPCR) signalling pathways, which control all aspects of eukaryotic physiology. Ligand-bound GPCRs initiate signalling by promoting exchange of GDP for GTP on the Gα subunit of heterotrimeric G proteins, thereby facilitating activation of downstream effectors. Signalling is terminated by the hydrolysis of GTP to GDP through intrinsic GTPase activity of the Gα subunit, in a reaction catalysed by the regulator of G protein signalling (RGS) proteins. Due to the problem of complexity in higher eukaryotic GPCR signalling, the matingresponse in Schizosaccharomyces pombe has been used to study GPCR signalling in isolation. In vivo data from quantitative assays of reporter strains and live-cell uorescence microscopy informs the development of an ordinary differential equation model of the signalling pathway, first described by Smith et al., 2009. The rate of nucleotide exchange on the Gα (Gpa1) is a key molecular mechanism controlling duration and amplitude of signalling response. The in uence of this is investigated through characterisation of Gpa1 nucleotide exchange mutants and perturbation of reaction rate parameters in the computational model. Further, this thesis also presents data relating to the temporal and spatial regulation of Rgs1 (the sole RGS protein for Gpa1). Using an inter-disciplinary approach, evidence is provided to suggest that an interaction between Rgs1 and the C-terminal tail of the GPCR (Mam2) tethers Rgs1 to the plasma membrane to facilitate its function. Finally, quantification of signalling at the single cell level is described. Time-lapse livecell imaging of uorescent reporter cells is optimised and single cell signalling response quantified using image analysis software. Single cell quantification provides greater insight into temporal dynamics, cell-to-cell variability, and highlights the existence of mechanisms for cellular decision-making.
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Caldji, Christian. "Early environmental regulation of neural systems mediating fearfulness." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103367.
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Postnatal handling of rat litters during the first week of life greatly decreases behavioural fearfulness to novelty in the adult offspring. Our first question was to what extent the Benzodiazepine/GABAA receptor complex, a system critical for the expression of fear, might be involved in mediating the observed reduced fearfulness in handled animals (H). Benzodiazepine receptor (BZ) binding was reduced in the amygdala and locus coeruleus (LC), regions important for the expression of fear in non-handled (NH) and maternally separated animals (MS). Moreover, levels of the mRNA for the gamma2 sub-unit of the GABAA receptor complex, which confers high affinity BZ binding, were higher in the amygdaloid nuclei as well as in the LC of handled compared with both NH and MS animals.Studies with the handling paradigm have lead to the idea that variations mother-pup interactions may actually be the cause of the handling effects. As adults, the offspring of mothers which exhibited high levels of licking/grooming and arched-back nursing (LG-ABN) showed substantially reduced behavioral fearfulness in response to novelty compared to the offspring of low LG-ABN mothers. In addition, the adult offspring of the high and low LGABN mothers showed the same receptor and molecular profiles as H and NH adult offspring. Corticotropin releasing factor (CRF) and alpha2 norepinephrine receptor levels, additional receptor systems thought to be important in the expression of fearfulness, differed in these animals too. Adoption studies give further support to the maternal hypothesis in the finding that the expression mRNA for the gamma2 sub-unit of the GABAA receptor complex can be differentially expressed as a result of different offspring to mother combinations.
Taken together, these findings suggest that early life events (ie: naturally occurring differences in maternal care) during the first few days of life have long-term effects on the development of central neurotransmitter systems, which mediate the expression of fearfulness to novelty.
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Riquelme, Zubiria Elia. "Analysing the role of secretion systems in the physiology and pathogenesis of Brucella." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTT084.
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La brucellose est une zoonose courante causée par des bactéries du genre Brucella. La maladie humaine représente une cause importante de morbidité dans le monde entier alors que la brucellose animale est associée a d’importantes pertes économiques dues majoritairement aux avortements et à l’infertilité chez les ruminants. La survie et la réplication des bactéries du genre Brucella à l’intérieur de cellules phagocytiques et non-phagocytiques dépend du système de sécrétion de type IV (T4SS) qui sécrète des effecteurs protéiques. Ces effecteurs sont capables de sentir et de modifier la biologie de la cellule hôte. Les séquences génomiques de Brucella n’ont pas montré d’autres systèmes de sécrétions spécialisés. Cependant, elles révèlent la présence du système Tat (twin arginine translocator). Cette étude porte sur le T4SS, très bien caractérisé, ainsi que sur le système Tat chez Brucella suis. Pour comprendre les mécanismes utilisés par Brucella pour délivrer ses effecteurs protéiques appartenant au T4SS, nous avons montré que le résidu Gly295 de la protéine VirB10 chez B. suis, situé au sein d’un gate domain (GxxGxxG) proche de la région antenna projection, contribue à la régulation du transfert de substrat à travers la membrane externe. Ceci a été validé à l’aide du système rapporteur CyaA qui indique une translocation plus importante des effecteurs de Brucella chez le mutant VirB10G295R. Il a été possible d’en conclure que la mutation G295R empêche le T4SS de réguler la sécrétion de ses effecteurs. Cela suggère donc que le canal adopte une conformation ouverte de façon constitutive ce qui conduit à une libération non régulée des effecteurs protéiques. Il est possible que Brucella puisse également sécréter des effecteurs via la voie Tat. Le système Tat est présent dans de nombreuses, mais pas de façon ubiquitaire, bactéries et est utilisé pour l’export de protéines repliées du cytosol à l’enveloppe bactérienne ou l’environnement extracellulaire. Un criblage in silico du génome de Brucella a été réalisé en utilisant le signal N-terminal SRRxFLK qui a révélé 27 substrats potentiels de ce système. Dans ce travail, malgré l’utilisation de diverses techniques, l’obtention d’un mutant tat de Brucella n’a pas été possible. Plus important, une analyse bio-informatique a indiqué que plusieurs des substrats prédits de Tat encodés par le génome de Brucella sont essentiels à de nombreux mécanismes physiologiques de la bactérie. De plus, des données de TnSeq ont établies que tatC est un gène essentiel. De ce fait, un autre système rapporteur in vivo a été utiliser pour confirmer la dépendance au système Tat des substrats prédits précédemment. Grâce à cette stratégie, il a été montré qu’un système hétérologue construit chez E. coli fonctionne pour identifier les séquences signal du système Tat de Brucella. En conclusion, ces travaux suggèrent que le système Tat est un système de transport protéique essentiel à la viabilité des bactéries du genre Brucella. Ces résultats contribuent à une meilleure compréhension des mécanismes de translocations des effecteurs protéiques du T4SS et donnent des informations sur la façon dont la voie Tat contribue à la physiologie de Brucella. Comprendre la biologie des bactéries responsables de la Brucellose est une étape essentielle pour le développement de mesures de contrôleBrucellosis is a widespread zoonotic disease caused by bacteria of the genus Brucella. The human disease represents an important cause of morbidity worldwide whereas animal brucellosis is associated with serious economic losses caused mainly by abortion and infertility in ruminants. Brucella virulence depends on its ability to survive and replicate within host cells. This requires the Brucella VirB type IV secretion system (T4SS). The T4SS translocates effector proteins which subvert the host cell biology and defences, allowing it to create a novel intracellular niche in which it survives and multiplies.The VirB T4SS is a multi-protein complex encoded by the 12 genes of the virB operon. While there is some information on the structure of the VirB T4SS, little is known about the mechanisms that Brucella uses to deliver T4SS effectors. In this thesis we showed that the Gly295 of VirB10 in B. suis, a residue within a conserved gate motif (GxxGxxG) near the antenna projection region, contributes to the regulation of substrate transfer across the outer membrane. This was validated with the CyaA reporter system which indicates a higher translocation of Brucella effectors in the VirB10G295R. We can conclude that the G295R mutation renders the T4SS unable to regulate the secretion this suggests, a constitutively open channel conformation that leads to the unregulated release of effector proteins.The VirB T4SS is the only complex secretion system used by Brucella.Brucella does use two transport systems to export proteins from the cytoplasm; the Sec system and the Tat system. Tat is present in many, but not all, bacteria and is used to export folded proteins from the cytosol to the bacteria envelope or to the extracellular environment. There have been no reports of investigation of the Brucella Tat system. . An in-silico screen of the Brucella genome using the consensus N-terminal signal SRRxFLK revealed 27 potential substrates. To investigate the role of the Tat system in Brucella physiology ad virulence, we attempted to create a Brucella tat mutant using several strategies: none were successful. Analysis of the predicted Tat substrates showed that several could be essential physiological processes, explaining why we could not mutate the Brucella Tat system. . Moreover, Tn-Seq data from the De Bolle group identified tatC as an essential gene. Therefore, we have used an alternative in vivo reporter system to confirm the Tat dependency of the predicted substrates. We proved that a heterologous system constructed in E. coli works to identify Brucella Tat signal sequences. Altogether, we proposed that the Tat system is an essential protein transport system for viability in Brucella spp. Our results contribute to a further understanding of the mechanisms of translocation of T4SS protein effectors and give information about how the Tat pathway is contributing to the role of physiology of Brucella. Understanding the biology of the pathogen that causes brucellosis is an essential step in the development of control measures
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Narayanaswamy, Variankaval. "Characterization of phase transitions in transdermal drug delivery systems." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/8645.
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Mournetas, Virginie. "Defining stemness of human embryonic stem cells : a systems biology approach." Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/2008879/.
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Human embryonic stem cells (hESCs) are undifferentiated cells arising from the inner cell mass of the blastocyst, which are able to self-renew or differentiate in vitro into specialised cell types. These pluripotent cells are a powerful tool to study human embryonic development and have great potential in the field of regenerative medicine. Human ESC pluripotency is governed by an intrinsic transcriptional network composed of the three well-known transcription factors OCT4, SOX2 and NANOG, whereas the role of extrinsic cell/microenvironment interactions in the maintenance of hESC stemness has been neglected to some extent. The aim of this work was to develop a systems biology approach oriented on these extrinsic factors and their links with the transcriptional network, in order to uncover some of the fundamental mechanisms underlying the stemness state. The thesis is divided into two complementary approaches: a top-down in silico study and a bottom-up in vitro study. The top-down in silico approach consists of a meta-analysis of hESC transcriptional data, leading to the construction of a hESC transcriptome. These mRNA data served as proxy for proteins in a protein-protein interaction database to build a hESC interactome. This interactome (or protein-protein interaction network) was structurally defined to identify the likely cell surface and extracellular proteins regulating hESC stemness by revealing the ’module organiser’ or hub proteins and the ’module connector’ or bottleneck proteins, along with the extracellular/transcriptional links. The bottom-up in vitro approach was the study of five of the previously identified cell surface/extracellular proteins in hESC fate decision. These candidates, together with OCT4, were stably knocked down using short hairpin (sh)RNAs and lentiviruses. The optimisation of the shRNA lentivirus production led to the development of a method for the direct quantification of these lentiviral particles. The effects of shRNA-mediated knockdown on hESC phenotype were investigated by assessing cell morphology and by determining the expression levels of the following groups of mRNAs: candidate stemness mRNAs, pluripotency mRNAs, as well as trophectoderm, endoderm, mesoderm and ectoderm mRNAs. We found that the candidates could modulate each other’s expression and appeared to regulate hESC commitment into different lineages. Furthermore, the expression levels of some of the candidates were regulated by OCT4. Taken together, these results suggest that by using the novel in silico approach developed during this project, it is possible to identify new stemness factors that could potentially have a role in either maintaining hESC self-renewal or in regulating lineage specification.
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Buratti, Sara <1981>. "Pharmaceutical residues in aquatic systems: mode of action and effects on mussel physiology." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3539/.
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Pharmaceutical residues contaminate aquatic ecosystems as a result of their widespread human and veterinary usage. Since continuously released and not efficiently removed, certain pharmaceuticals exhibit pseudo-persistence thus generating concerns for the health of aquatic wildlife.
This work aimed at assessing on mussels Mytilus galloprovincialis, under laboratory conditions, the effects of three pharmaceuticals, carbamazepine (antiepileptic), propranolol (β-blocker) and oxytetracycline (antibiotic), to evaluate if the human-based mode of action of these molecules is conserved in invertebrates. Furthermore, in the framework of the European MEECE Programme, mussels were exposed to oxytetracycline and copper at increasing temperatures, simulating variations due to climate changes.
The effects of these compounds were assessed evaluating a battery of biomarkers, the expression of HSP70 proteins and changes in cAMP-related parameters.
A decrease in lysosomal membrane stability, induction of oxidative stress, alterations of cAMP-dependent pathway and the induction of defense mechanisms were observed indicating the development of a stress syndrome, and a worsening in mussels health status. Data obtained in MEECE Programme confirmed that the toxicity of substances can be enhanced following changes in temperature. The alterations observed were obtained after exposure to pharmaceuticals at concentrations sometimes lower than those detected in the aquatic environment. Hence, further research is advisable regarding subtle effects of pharmaceuticals on non-target organisms.
Furthermore, results obtained during a research stay in the laboratories of Cádiz University (Spain) are presented. The project aimed at measuring possible effects of polluted sediments in Algeciras Bay (Spain) and in Cádiz Bay, by assessing different physiological parameters in caged crabs Carcinus maenas and clams Ruditapes decussatus exposed in situ for 28 days. The neutral red retention assay was adapted to these species and proved to be a sensitive screening tool for the assessment of sediment quality.
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Hung, You-jou. "Shoulder position sense and kinesthetically guided reaching accuracy in individuals with anterior shoulder instability." Diss., University of Iowa, 2008. https://ir.uiowa.edu/etd/204.
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Altered neuromuscular control due to compromised position sense may contribute to shoulder instability. The purpose of this study was to investigate whether unstable shoulder subjects exhibit larger errors than intact shoulder subjects in kinesthetically guided active positioning and reaching that are of greater functional significance than passive testing of shoulder position sense. Ten subjects with a history of anterior shoulder dislocation and 15 intact shoulder subjects participated in the study. Shoulder position sense was examined with three different protocols (imposed motion to remembered shoulder rotation angles and active shoulder abduction/rotation to verbally specified positions) with targets located in both the mid- and end-range of rotation. Three dimensional end-point accuracy of kinesthetically guided reaches to visually specified targets, along with the shoulder rotation angle and scapula orientations at the end-point, were also analyzed. In agreement with previous studies, unstable shoulder subjects exhibited significantly larger errors in perception of shoulder joint angles than healthy controls in a protocol involving imposed motion to remembered shoulder rotation angles. However, the clinical significance of the observed deficit is questionable because the averaged rms error differences between unstable and intact shoulders were relatively small (average: 1.8°). During tests of active positioning, unstable shoulder subjects were able to move the shoulder to verbally defined angles as accurately as healthy controls in both shoulder abduction and rotation. Unstable and intact shoulder subjects exhibited similar reaching accuracy and scapular orientations in the kinesthetically guided reaching test, but unstable shoulder subjects consistently used less shoulder rotation angle than healthy controls. However, they were able to point to a remembered target as accurately as intact shoulder subjects, suggesting that a different reaching strategy was adopted by unstable shoulder subjects to minimize shoulder rotation. Results of this study show that unstable shoulder subjects can perceive shoulder angles and reach to visually specified targets in space as accurately as healthy controls in functional activities with voluntarily arm movements. The results suggest that less sensitive joint receptors due to over-stretched shoulder stabilizers following shoulder injury have little impact on the neuromuscular control of the shoulder joint.
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Bursell, James David Hingston. "Swelling-activated membrane transport systems in vertebrate and protozoan cells : a comparative study." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337564.
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Williamson, Beth. "Determinants of transcriptional regulation of transport and oxidative processes in human model systems." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/15053/.
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Initial predictions of drug response and drug-drug interactions (DDIs) are made following high-throughput in vitro screening. Such assays are indispensible in the pharmaceutical industry to determine the metabolism, transport and pharmacokinetics of new chemical entities. However, they often fail when extrapolated to in vivo response due to unsuitable pharmacokinetic or pharmacodynamic prediction. The primary aim of this thesis was to investigate and understand the differences in the expression profiles of drug disposition genes, between transformed hepatic cell lines and primary human hepatocytes. Primary human hepatocytes were also analysed to determine uptake contribution, induction and genotype of key drug disposition-relevant genes. The loss of hepatic phenotype in HepG2 and Huh7 cells is partly due to the altered expression of transcriptional regulators including; chaperones, co-chaperones, co-activators and co-repressors. Indeed, Chapter 2 of this thesis shows lower levels of the Gadd45β and PGC1α gene expression in HepG2 cells corresponds to a deficient expression and activity of cytochrome P450 3A4 (CYP3A4), with the levels reducing further as cell passage increases, in comparison to primary human hepatocytes. HepG2 cells were transfected with a novel complex transfection of Gadd45β and PGC1α with the aim to improve CYP3A4 activity in Chapter 3. CYP3A4 activity was improved by 54% and induction response was enhanced in comparison to control cells with no off-target effects. Over the last decade it has become apparent that transporters can play a significant role in the disposition of many drugs. Organic anion transporting polypeptide (OATP) transporters have received considerable recent attention since they mediate sodium-independent uptake of a broad array of xenobiotics. A method to determine the specific contribution of OATP1B1 in the hepatic uptake was successfully optimised and applied for 5 therapeutic drugs in Chapter 4. Future application of this strategy is likely to have broad importance in determining relative contribution that individual transporters play in drug disposition. To prevent accumulation and toxicity of xenobiotics, biotransformation and transport of foreign compounds occurs. However, these processes can be altered by induction or inhibition mechanisms. Rifampicin is a first line drug in tuberculosis (TB) treatment but it is a potent inducer of CYPs and transporters. DDIs during TB treatment are common but the induction potential of different rifamycins has not been comprehensively ranked. Chapter 5 investigated the induction potential of rifampicin, rifapentine and rifabutin. Rifampicin significantly induced CYP3A4, ABCB1, OATP1B1 and ABCC2 in primary human hepatocytes. Induction by rifabutin was observed for CYP3A4, OATP1B3 whilst rifapentine only significantly induced OATP1B1. This work serves as a basis for further study into the extent to which rifamycins induce key metabolism and transporter genes. Nuclear receptors (NR) regulate the expression of CYPs and drug transporters influencing pharmacokinetics. PXR and VDR have been found to synergistically increase CYP3A4 expression and activity in intestinal cell lines. This effect has been observed in vivo with seasonal variations apparent for CYP3A4 substrates. In Chapter 6, novel associations between vitamin D receptor polymorphisms and expression of it and its target genes involved in drug disposition were shown in D2 intestinal biopsies. This thesis reports generation of model systems and their application to enable many questions to be answered relating to pharmacokinetics and DDIs. The thesis forms a solid platform from which to further investigate these issues in future studies.
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Koslow, Jennifer Marie. "Mixed mating systems, pathogens, and plant community ecology." [Bloomington, Ind.] : Indiana University, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3232578.
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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2006."Title from dissertation home page (viewed July 11, 2007)." Source: Dissertation Abstracts International, Volume: 67-08, Section: B, page: 4208. Advier: Keith Clay.
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Lam, Minh Phuc. "Interactions of acute alcohol with the endogenous opioid and corticotropin-releasing hormone systems in the rat brain." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=96687.
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Alcohol abuse and dependence are complex psychiatric disorders involving multiple neurobiological systems in various brain regions including the central amygdala (CeA). As part of the extended amygdala complex, the CeA has been demonstrated to have a key role in the development of alcohol addiction. In addition, alcohol induces multiple interactions of neurochemical systems including the endogenous opioid and corticotropin-releasing hormone (CRH) systems. Thus, the main objective of the studies in this dissertation was to investigate the effects of acute alcohol administration in the rat on the activity of the endogenous opioid peptides and CRH at the level of CeA, as well as the possible interactions between these two neurochemical systems. Using the in vivo microdialysis technique, the effects of acute alcohol administration on the release of opioid peptides (endorphins, enkephalins, and dynorphins) and CRH at the level of CeA were investigated. Additional studies explored the effects of microinjections in CeA of either CRH or CRH receptor type 1 (CRHR1) and type 2 (CRHR2) antagonists on the release of beta-endorphin and dynorphin peptides under basal conditions and in response to acute alcohol exposure. These in vivo microdialysis studies demonstrated that at the level of CeA (1) acute alcohol induced a dose- and time-dependent increase in the extracellular concentrations of beta-endorphin and dynorphin A1-8 but not of met-enkephalin; (2) acute alcohol induced a dose-and-time-dependent increase in the extracellular concentrations of CRH; (3) microinjection of CRH induced an increase in the extracellular concentrations of beta-endorphin; (4) blockade of CRHR1 and CRHR2 attenuated the alcohol-induced increase in the extracellular concentrations of β-endorphin; (5) microinjection of CRH induced an increase in the extracellular concentrations of dynorphin A1-8 and (6) blockade of CRHR2 attenuated the alcohol-induced increase in the extracellular concentrations of dynorphin A1-8. In summary, acute alcohol exposure induced an increase in CRH release at the level of CeA, which may interact with CRHR1 and CRHR2 to stimulate the release of beta-endorphin and with CRHR2 to stimulate the release of dynorphinA1-8 in CeA. Thus, it may be proposed that the interactions between the CRH and opioid peptide systems in response to acute alcohol administration at the level of CeA may be important in determining alcohol consumption.L'abus d'alcool et la dépendance sont des troubles psychiatriques complexes impliquant des multiples systèmes neurobiologiques dans diverses régions du cerveau dont l'amygdale centrale (CeA). Dans le cadre du complexe amygdalien étendu, la CeA a été démontré à jouer un rôle clé dans le développement de la dépendance à l'alcool. Ainsi, l'objectif principal des études dans cette thèse était d'étudier les effets de l'administration d'alcool à court terme sur l'activité des peptides opioïdes endogènes et l'hormone corticolibérine (CRH) au niveau de la CeA, ainsi que les interactions entre ces deux systèmes neurochimiques. En utilisant la technique de microdialyse in vivo, les expériences de cette thèse ont démontré les effets de l'administration d'alcool à court terme sur la libération des peptides opioïdes (endorphines, enképhalines, et dynorphines) et CRH au niveau de la CeA. De plus, les expériences de cette thèse ont demontré les effets des microinjections dans la CeA soit CRH ou les antagonistes des récepteurs CRH de type 1 (CRHR1) et de type 2 (CRHR2) sur la libération des beta-endorphine et dynorphine dans des conditions basales et après un traitement avec l'alcool à court terme. Les résultats de ces études de microdialyse in vivo ont démontré qu'au niveau de la CeA (1) le traitement avec l'alcool à court terme a induit des augmentations des concentrations extracellulaires de beta-endorphine et dynorphine A1-8 et non pas d'enképhaline qui sont dépendantes sur la dose d'alcool et le temps après l'injection; (2) le traitement avec l'alcool à court terme a causé une augmentation des concentrations extracellulaires de CRH dépendante sur la dose d'alcool et le temps après injection; (3) la microinjection de CRH a produit une augmentation des concentrations extracellulaires de beta-endorphine; (4) le blocage de CRHR1 et CRHR2 a atténué l'augmentation des concentrations extracellulaires de β-endorphine induit par l'alcool; (5) la microinjection de CRH a induit une augmentation des concentrations extracellulaires de dynorphine A1-8 et (6) le blocage de CRHR2 a atténué l'augmentation des concentrations extracellulaires de dynorphine A1-8 induit par l'alcool. En résumé, le traitement avec l'alcool à court terme a induit une augmentation de la CRH au niveau de la CeA. Après sa libération, la CRH peut interagir avec CRHR1 et CRHR 2 pour stimuler la libération des endorphines et l'interaction avec CRHR2 peut stimuler la libération des dynorphines A1-8 au CeA. Ainsi, il peut être proposé que les interactions entre les systèmes opioidergiques et la CRH au niveau de la CeA causées par l'administration d'alcool à court terme pourraient être importantes dans la consommation d'alcool.
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Miraldi, Emily R. (Emily Rae). "Bridging the gap between protein-tyrosine phosphorylation networks, metabolism and physiology in liver-specific PTP1b deletion mice." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/72824.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Computational and Systems Biology Program, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references.
Metabolic syndrome describes a complex set of obesity-related disorders that enhance diabetes, cardiovascular, and mortality risk. Studies of liver-specific protein-tyrosine phosphatase lb (PTPlb) deletion mice (L-PTPlb-/-) suggests that hepatic PTPlb inhibition would mitigate metabolic syndrome progression through amelioration of hepatic insulin resistance, endoplasmic reticulum stress, and whole-body lipid metabolism. However, the network alterations underlying these phenotypes are poorly understood. Mass spectrometry was used to quantitatively discover protein phosphotyrosine network changes in L-PTP lb-/- mice relative to control mice under both normal and high-fat diet conditions. A phosphosite set enrichment analysis was developed to identify numerous pathways exhibiting PTPlb- and diet-dependent phosphotyrosine regulation. Detection of PTP lb-dependent phosphotyrosine sites on lipid metabolic proteins initiated global lipidomics characterization of corresponding liver samples and revealed altered fatty acid and triglyceride metabolism in L-PTPlb-/- mice. Multivariate modeling techniques were developed to infer molecular dependencies between phosphosites and lipid metabolic changes, resulting in quantitatively predictive phenotypic models.
by Emily R. Miraldi.
Ph.D.
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Santos, Magalhães André. "Subjective and objective assessment of physically active people with knee injury." Thesis, University of Kent, 2016. https://kar.kent.ac.uk/60066/.
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Knee injuries are highly prevalent in physically active individuals and are frequently associated with sport participation. Independently of the nature of the injury, subjective and objective clinical measures are used to assess, monitor and evaluate treatment outcomes in this population. To be clinically meaningful, these outcome measures should be relevant to the condition, the anatomical area, the individual or population, and importantly, possess adequate psychometric properties. Despite a high prevalence of knee injuries, there are several aspects of the subjective and objective knee evaluation in physically active individuals that remain unclear or have not been considered in previous research. The main aim of the present thesis was to fill some of the gaps identified in the literature regarding both subjective and objective knee measures in physically active individuals. Therefore, this thesis was divided into two distinct parts. The first part looked at the patient-reported outcome (PRO) measures of the knee and physical activity, and consisted of two studies. The first study was a systematic review conducted to explore the PRO measures that are commonly used in the evaluation of physical activity and return to sport following autologous chondrocyte implantation (ACI). Aiming as well, to provide a critical analysis of these instruments from a rehabilitative perspective. This review revealed not only the heterogeneity in the selection, but also in the timing and reporting of patient-reported activity scoring instruments following ACI, which makes a systematic comparison difficult and introduces bias into the interpretation of these outcomes. Another important finding of this review, was that the instruments currently used to evaluate postoperative outcomes in an articular cartilage repair population do not always fulfil the rehabilitative needs of physically active individuals. The second study was conducted in recreational marathon runners and aimed to provide normative values for a widely used knee specific PRO measure in athletes with knee injury, the Knee Injury Osteoarthritis Outcome Score (KOOS). Alongside the normative KOOS subscales values stratified by age group and history of knee injury that were presented, this study also showed that recent history of knee running-related injury (RRI) has a negative impact on the KOOS scores. In runners with no history of knee RRI, the results observed suggested a lack of interaction between KOOS subscale values and age. Furthermore, the KOOS values seen were substantially higher compared to previously published normative population-based KOOS values. The second part of the present thesis comprised three experimental studies concerning single-leg cycling (SLC) exercise testing, in particular assessing the potential use of the self-paced test (SPT) concept as an objective measure following knee surgery. The first study analysed the reliability of a 5x2 min stages SPT anchored to the rate of perceived exertion (RPE) for SLC exercise testing. This study showed that this test protocol elicits reliable cardiorespiratory and metabolic responses. The second study examined the validity of the SPT protocol used in the previous study, through a concurrent comparison against a conventional fixed power incremental SLC exercise test. This investigation showed that the 5x2 min SPT provides a valid objective means for assessing peak aerobic capacity in SLC exercise testing. Moreover, it may be associated with increased activity enjoyment comparatively to conventional testing. The third and last experimental study investigated the effect of a 10 kg counterweight device (CW10) on cardiorespiratory, metabolic and perceptual responses to SLC exercise testing. The results of this study demonstrated that the CW10 despite eliciting an improvement in the activity enjoyment, did not affect peak cardiorespiratory and metabolic responses to SLC exercise testing. When matched for test duration the SPT elicited higher peak power output and peak oxygen consumption than conventional incremental testing, regardless of the CW10 usage or not. In conclusion, the original work of the present thesis increases the body of knowledge of two distinct, but complementary fields in the subjective and objective knee assessment of physically active individuals. The outcomes provided both on PRO measures and SLC exercise testing, may have impact on the clinical practice of clinicians, sport rehabilitation professionals and researchers.
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Pethick, Jamie. "The effects of neuromuscular fatigue on the complexity of isometric torque output in humans." Thesis, University of Kent, 2016. https://kar.kent.ac.uk/60067/.
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The temporal structure, or complexity, of torque output is thought to reflect the adaptability of motor control and has important implications for system function, with high values endowing greater adaptability in response to alterations in task demand. The aim of this thesis was to investigate the effect of neuromuscular fatigue on the complexity of isometric muscle torque output. It was hypothesised that neuromuscular fatigue would lead to a reduction in the complexity of muscle torque output, as measured by approximate entropy (ApEn), sample entropy (SampEn) and the detrended fluctuation analysis (DFA) α scaling exponent. The first experimental study (Chapter 4) demonstrated that muscle torque complexity was significantly reduced during both maximal and submaximal intermittent fatiguing contractions, with the values at task failure indicative of increasingly Brownian noise (DFA α > 1.50). It was subsequently shown in the second study (Chapter 5) that this reduction in complexity occurred exclusively during contractions performed above the critical torque. It was next demonstrated, in the third study (Chapter 6), that pre-existing fatigue significantly reduced torque complexity and time to task failure, but still resulted in consistent values of complexity at task failure regardless of the time taken to reach that point. In the fourth study (Chapter 7) caffeine ingestion was found to slow the rate of reduction in torque complexity with fatigue, seemingly through both central and peripheral mechanisms. Finally, in the fifth study (Chapter 8) eccentric exercise decreased the complexity of torque output, with values only recovering to baseline levels after 24 hours recovery, in comparison to only 10 minutes recovery following isometric exercise. These results demonstrate that torque complexity is significantly perturbed by neuromuscular fatigue. This thesis has thus provided substantial evidence that the complexity of motor control during force production becomes less complex, and that muscles become less adaptable, with neuromuscular fatigue.
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Fan, Li 1967. "Interactions of renin-angiotensin and natriuretic peptide systems in control of blood pressure during ovine pregnancy." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39904.
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This thesis focuses on the renin-angiotensin system and atrial natriuretic factors (ANF) two hormonal systems which are stimulated and which may exert important antagonizing actions on the regulation of mean arterial pressure (MAP) and body fluid homeostasis during pregnancy. All experiments were conducted in healthy nonpregnant and/or pregnant (gestational age of 105 to 140 days, term = 145 days) mixed breed ewes, using a facility designed for studies of large animals. Findings from the first study with unilateral denervated kidneys provide evidence that renal nerves are a necessary component in the control of renin secretion in both nonpregnant and pregnant ewes. The second study demonstrates that angiotensin II (AngII) and ANF do not account for the dramatic suppression of renin secretion in response to the reduction of renal perfusion pressure in sheep with bilateral renal denervation. The data from these two studies suggest that the renal baroreceptors influence renin secretion indirectly through activation of renal afferents rather than by a direct action on the juxtaglomerular apparatus. In order to study the possible effects of increased plasma AngII on ANF production during pregnancy, four doses of AngII (0.5, 5, 20, 40 ng/kg/min) and nitroprusside were simultaneously infused to separate indirect hemodynamic actions on ANF secretion from direct hormonally mediated effects on ANF secretion by AngII. The data clearly show that AngII increases plasma ANF in a dose-dependent manner but: only in the presence of the AngII pressor effect. A striking finding was the demonstration that the natriuretic and diuretic responses to intrarenal artery infusion of three doses of ANF (0.3, 1.5, 3.0 pmol/kg/min) are increased during ovine pregnancy and these responses are solely limited to actions on the distal part of the nephron without altering renal vascular or glomerular function. Finally, a study with 10 days of intrarenal artery infusion of low dose AngII (1 ng/kg/m
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August, Elias. "Stability and dissipativity theory for nonnegative and compartmental dynamical systems." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/13068.
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Marques, Bernardo José Santos. "Veracity: low cost physiology assessment tool using virtual reality." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/22731.
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Mestrado em Engenharia de Computadores e TelemáticaAnxiety disorders affect many individuals, conditioning their daily life routines. Specific phobia is one example of an anxiety disorder, which is an irrational fear towards an object, or situation. Phobics felt a distorted reality, and usually try to avoid the phobic element, which will only intensify the problem. The evolution of technology and the miniaturization brought to the foreground not only allow the development of portable solutions for the assessment of psychological and behavior but also new possibility to mimic the real world likes Virtual Reality (VR) outside of the laboratory setting. Recent studies, describe Virtual Reality exposure as effective, when compared to in vivo exposure, with the benefit of being less aggressive to the phobic individual. In this dissertation, we propose Veracity, an affordable and portable system, which relies on VR to present more ecological and virtual stimuli to phobic individuals while monitoring their physiological and behaviour response. We used spider phobias as the main case study of our system. While presenting the VR stimuli, using a game divided in a set of increasing difficulty levels, Veracity allows the interaction with the virtual environment through hand gesture. Simultaneously the individual’s reaction is acquired (ECG, HR, RR, VIDEO, Screenshots, 3D objects tracking, etc.) using external resources and two smartphone applications. Veracity also supports data management for post processing integrated with the cloud. The gamification approach and its ability to customize the virtual stimuli provides enough versatility to foster its usefulness in clinical practice as a solution to monitor and elicit natural reactions from individuals with specific phobias.
Distúrbios de ansiedade afetam muitos indivíduos, condicionando as suas rotinas. Um exemplo é o caso da fobia específica, um medo irracional em relação a um objeto ou situação. Indivíduos fóbicos sentem uma realidade distorcida, e geralmente, tentam evitar o elemento fóbico, o que intensifica o problema. A evolução da tecnologia não só permite o desenvolvimento de soluções portáteis para a avaliação fisiológica e comportamental, criando novas possibilidades para imitar o mundo real utilizando Realidade Virtual (VR) fora do ambiente controlado de laboratório. Estudos recentes, descrevem a exposição a VR como sendo eficaz quando comparada com a exposição in vivo, sendo menos agressiva para o individuo. Nesta dissertação, propomos o Veracity, um sistema portátil e economicamente acessível, para apresentação de estímulos virtuais a indivíduos fóbicos e interação com esse ambiente através do reconhecimento da mão e gestos enquanto a sua resposta fisiológica e comportamental é monitorizada. O principal caso de estudo do nosso sistema é a fobia de aranhas. O sistema é rápido de configurar, permite a recolha de dados fora do ambiente de laboratório e a exposição a estímulos, que permitem reações mais naturais. Simultaneamente, a reação do indivíduo é adquirida (ECG, HR, RR, VIDEO, Imagens, 3D tracking, etc.), utilizando recursos externos e duas aplicações para dispositivos móveis. Veracity suporta ainda a gestão dos dados recolhidos, para pósprocessamento integrado com a cloud. A sua aproximação baseada em jogos e a sua capacidade de personalizar os estímulos virtuais, proporciona um nível de versatilidadeque, que promove a sua utilidade na prática clínica como uma solução para provocar reações naturais e monitorizarem individuos com fobias específicas.
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Hu, Keli. "Signal transduction systems involved in ischemic preconditioning and ATP-sensitive K+ channels." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0002/NQ44456.pdf.
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Mohtat, Nadereh. "Study of magnetic field effects on radical reactions and of the mobility of transients in microheterogeneous systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ28361.pdf.
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Routledge, Hayden Swailes. "Regulation of myogenic tone in cerebral and mesenteric resistance arteries by metabolic agents and second messenger systems." Thesis, University of Glasgow, 2000. http://theses.gla.ac.uk/4904/.
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1. The pressure-perfusion myograph. permeabilisation techniques and also intracellular membrane potential recordings were used to examine the regulation of myogenic tone in cerebral and mesenteric resistance arteries by metabolic agents and second messenger systems. 2. After pressurisation to 60 mmHg, rat isolated mesenteric and cerebral resistance arteries developed spontaneous myogenic tone, resulting in a 26 ± 1% (n = 42) and 30 ± 2% (n = 14) reduction in diameter respectively. 3. The metabolic vasodilator adenosine and the KATI' channel opener cromakalim each produced a dose-dependent dilatation of pressurised mesenteric arteries. The cromakalim-evoked dilatation was inhibited by glibenc1amide (l J.lM), demonstrating the presence of the KATI' channel in the mesenteric artery and their activation as the mechanism for cromakalim-evoked dilatation. In contrast neither adenosine nor cromakalim produced a dilatation of pressurised cerebral arteries. 4. Adenosine-evoked dilatation of mesenteric arteries was unaffected by the nitric oxide synthase inhibitor L-NAME (100 IlM). antagonists of the KATI' channel (gJibenclamide; 1 J.lM), the small conductance Ca2' activated K+ channel (apamin; 0.3 J.lM) and the large conductance, Ca2! activated K+ channel (TEA; 1 mM). Further to this, cromakalim (10 IlM) but not adenosine (100 J.lM) produced a hyperpolarisation of the pressurised mesenteric artery. This suggests that neither nitric oxide synthesis nor K+ channel activation contributed to the adenosine-evoked dilatation. 5. Adenosine evoked adose-dependent dilatation of p-escin permeabilised mesenteric arteries; where the intracellular Ca" concentration was clamped to ~600 nM. The mechanism of adenosine-evoked dilatation may involve a decreased myofilament Ca2+ sensitivity. 6. An increase in extracellular potassium ion concentration ([K+lo) may link increased neuronal activity and regional cerebral blood flow. Elevation of [K+Jofrom 4.7 to 10 mM evoked a sustained dilatation of isolated pressurised thalamo-perforating cerebral arterioles. 7. The K+-evoked dilatation was inhibited by the inward rectifier K+ channel (K1R) inhibitor Ba2+ (50J.lM), and the K+ channel inhibitor cesium (20mM) but was not blocked by inhibitors of the ATP-sensitive (KATP)and the Ca2 + -activated K+ channel (KcJ, glibenclamide (l J.lM) and TEA (lmM) respectively. Nor was the dilatation altered with the neurotoxin tetrodotoxin (TTX, 0.3 J.lM). The K+--evoked dilatation was associated with a membrane hyperpolarisation to -58 ± I mV (n = 5), from a control value of -42 ± 1 mV (n = 10). 8. It is proposed that increased [K+Jo evokes a dilatation of thalamoperforating cerebral arteries via an activation of KIR channels and smooth muscle cell hyperpolarisation. 9. An increase in [Ca2+]o to approximately 700 nM evoked a 30 ± 3 % (n = 28) constriction of isolated ~-escin permeabilised cerebral resistance arteries. 10. Under [Ca2+1 clamped conditions the putative PKC activator indolactam evoked a 20 ± 2% constriction of the artery. The PKC inhibitor (PKC(19_ 36); I IlM) produced a near maximal (85 ± 4 %) reversal of the indolactam-evoked constriction of the artery, while PKC(19_36) (1 IlM) produced only a minor (12 ± 3 %) reversal of the Ca2+-induced constriction, thus confirming that the indolactam-evoked constriction was due to an activation ofPKC. 11. The MLCK antagonist SM-l (100 JlM) reversed both the Ca2+_ and the indolactam-evoked constriction of the artery. The calmodulin antagonist RS-20 (0.1 - 100 JlM) dose-dependently reversed the Ca2 + -evoked constriction but, even up to a concentration of 300 JlM, did not reverse the indolactam evoked-constriction of the artery. 12. It is proposed that MLCK but not calmodulin plays a role in the PKCevoked smooth muscle contraction.
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Locke, James C. W. "A systems biology approach to the Arabidopsis circadian clock." Thesis, University of Warwick, 2006. http://wrap.warwick.ac.uk/58550/.
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Circadian clocks involve feedback loops that generate rhythmic expression of key genes. Molecular genetic studies in the higher plant Arabidopsis theliene have revealed a complex clock network. We begin by modelling the first part of the Arabidopsis clock network to be identified, a transcriptional feedback loop comprising TIMING OF CAB EXPRESSION 1 (TOCl), LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1). As for many biological systems, there are no experimental values for the parameters in our model, and the data available for parameter fitting is noisy and varied. To tackle this we construct a cost function, which quantifies the agreement between our model and various key experimental features. We then undertake a global search of parameter space, to test whether the proposed circuit can fit the experimental data. Our optimized solution for the Arabidopsis clock model is unable to account for significant experimental data. Thanks to our search of parameter space, we are able to interpret this as a failure of the network architecture. We develop an extended clock model that is based upon a wider range of data and accurately predicts additional experimental results. The model comprises two interlocking feedback loops comparable to those identified experimentally in other circadian systems. We propose that each loop receives input signals from light, and that each loop includes a hypothetical component that had not been explicitly identified. Analysis of the model predicts the properties of these components, including an acute light induction at dawn that is rapidly repressed by LHY and CCAL We find this unexpected regulation in RNA levels of the evening-expressed gene GIGANTEA (GI), supporting our proposed network and making GI a strong candidate for this component. We go on to develop reduced models of the Arabidopsis clock to aid conceptual understanding, and add a further proposed feedback loop to develop a 3-loop model of the circadian clock. This 3-loop model is able to reproduce further key experimental data.
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Chik, Tai-wai David, and 戚大衛. "Global coherent activities in inhibitory neural systems: Chik Tai Wai David." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31040408.
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Jia, Wei-Guo. "Calcium-related signal transduction systems in developing visual cortex." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30927.
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Neuronal connections in cat visual cortex are highly susceptible to visual experience at early postnatal age and thus serve as a useful model of neural plasticity. The biochemical mechanisms underlying this cortical plasticity remain unclear. In this thesis, the development of several elements in calcium-related signal transduction systems, including the type-1 muscarinic and alpha-1 adrenoceptor systems as examples of cell surface receptors and protein kinase C. calcium/calmodulin dependent kinase II and inositol 1,4,5 phosphotate receptors as second messenger targets, were investigated using the methods of immunocytochemistry and autoradiography. The results show that each receptor develops with its own time-table and laminar distribution; the various elements all culminate and display the maximal colocalization during the critical period; and, only at this age, the cortical levels of the receptors and kinases are dependent on subcortical afferents. The results suggest that cell surface receptors and their second messenger targets develop in specific temporal and spatial patterns, which may be both genetically and environmentally determined, and this specific sequence of development of the molecules for signal transduction results in a series of modifications in the morphology and physiology of the developing cortex leading to its maturation.Medicine, Faculty of
Graduate
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Insel, Nathan. "Physiology of the medial frontal cortex during decision-making in adult and senescent rats." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/196140.
Full textAbstract:
Convergent evidence suggests that the dorsal medial prefrontal cortex (dmPFC) makes an important contribution to goal-directed action selection. The dmPFC is also part of a network of brain regions that becomes compromised in old age. It was hypothesized that during decision-making, some process of comparison takes place in the dmPFC between the representation of available actions and associated values, and that this process is changed with aging. These hypotheses were tested in aged and young adult rats performing a novel 3-choice, 2-cue decision task. Neuron and local field potential activity revealed that the dmPFC experienced different states during decision and outcome phases of the task, with increased local inhibition and oscillatory (gamma and theta) activity during cue presentation, and increased excitatory neuron activity (among regular firing neurons) at goal zones. Although excitatory and inhibitory activity appeared anti-correlated over phases of the decision task, cross-correlations and the prominent gamma oscillation revealed that excitation and inhibition were highly correlated on the millisecond scale. This "micro-scale" coupling between excitation and inhibition was altered in aged rats and the observed changes were correlated with changes in decision and movement speeds of the aged animals, suggesting a putative mechanism for age-related behavioral slowing. With respect to decision-making, both aged and young adult rats learned over multiple days to follow the rewarded cue in the 3-choice, 2-cue task. Support for the hypothesis that the dmPFC simultaneously represents alternative actions was not found; however, neuron activity selective for particular goal zones was observed. Interestingly, goal-selective neural activity during the decision period was more likely to take place on error trials, particularly on high-performing sessions and when rats exhibited a preference for a particular feeder. A possible interpretation of these patterns is that goal representations in the dmPFC might have sometimes overruled learned habits, which are likely to be involved in following the correct cue and which are known to be supported by other brain regions. These results describe fundamental properties of network dynamics and neural coding in the dmPFC, and have important implications for the neural basis of processing speed and goal-directed action.
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Kumar, Jothi Dinesh. "Novel stromal cell signalling systems in oesophageal cancer." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/15257/.
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Myofibroblasts are recognised to play an important role in wound healing and the maintenance of tissue integrity. In addition, they are increasingly recognised to provide a supporting microenvironment for cancer cells. They secrete a variety of chemokines, cytokines, growth factors and proteases that collectively regulate cell proliferation, migration and invasion. Specific chemokines are known to recruit mesenchymal stromal cells (MSCs) to both tumours and normal tissue which may then give rise to myofibroblasts. Proteomic studies by Holmberg and Varro (unpublished observations) identified chemerin as an upregulated chemokine in conditioned media (CM) from oesophageal cancer associated myofibroblasts (CAMs) compared to adjacent tissue myofibroblasts (ATMs). Chemerin is potent chemo-attractant for immune and inflammatory cells. The objectives of this thesis were (a) to functionally characterise the oesophageal myofibroblasts,(b) validate the findings of previous proteomic studies and (c) determine the role of chemerin in MSC migration. Oesophageal CAMs from both squamous and adenocarcinoma tumours were shown to be more proliferative than their paired ATMs, or normal tissue myofibroblasts (NTMs). In addition, CAM conditioned media increased the proliferation and migration of two oesophageal cancer cell lines (OE21 and OE33) and stimulated MSC migration compared to ATM CM. The data suggest oesophageal CAMs promote an aggressive tumour microenvironment. Western blotting and ELISA confirmed increased chemerin secretion by squamous carcinoma CAMs. Chemerin and conditioned media from squamous carcinoma CAMs, stimulated MSC and OE21 cell migration; Chemerin neutralizing antibody reversed these effects and siRNA knockdown of chemerin in CAMs, or of its cognate receptor ChemR23 in MSCs, decreased migratory responses. Studies using pharmacological inhibitors or Western blot of cellular proteins indicated that chemerin stimulated MSCs via PKC, and p42/44, p38 MAP and JNK kinases. Macrophage Inhibitory Factor (MIF) was identified as a putative chemerin target in MSCs and validated by ELISA and Western blot of MSC media and cell extracts. MIF inhibited MSC migration in response to low or moderate concentrations of chemerin, indicating that it might restrain MSC migration in normal tissues but not in cancers where chemerin is elevated. Finally, confirmation of chemerin-chemR23 interactions was obtained using a chemR23 antagonist, CCX832. Chemerin induced MSC and OE21 cell migration was inhibited by CCX832. Moreover, transendothelial migration of MSCs in response to chemerin or CAM conditioned media was reversed by CCX832. Transendothelial migration was also shown to depend on chemerin-stimulated MMP-2 secretion. These findings indicate a molecular mechanism by which MSCs are recruited to tumours. Taken as a whole, this work indicates that myofibroblasts derived from oesophageal cancers differ from those in adjacent or normal tissue. The finding of increased chemerin in these cells is novel and may be relevant to MSC recruitment. Since it is possible to inhibit the effects of chemerin on MSCs using CCX832, there is the potential for a novel therapeutic approach to prevent cancer progression.
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Orlowski, John M. "Evaluation of input-intensive soybean management systems and the effect of lactofen application on soybean physiology." UKnowledge, 2015. http://uknowledge.uky.edu/pss_etds/66.
Full textAbstract:
In an effort to maximize yields, many soybean growers have begun moving to intensive, input-based soybean management systems. However, limited reliable information exists about the effect of these inputs on soybean yield. The purpose of this study was to evaluate the effect of individual inputs and combinations of inputs as part of high-yield management systems on soybean seed yield and to determine the effect of one of these inputs, lactofen, on soybean physiology. Small plot studies were established in nine states across the Midwest. A number of commercially available soybean inputs were evaluated individually and in combination to determine their effect on soybean yield and quality. Lactofen and comparison treatments were applied to soybeans at multiple growth stages and yield and yield components were determined. When examined across environments, input-intensive combination treatments increased soybean yields from 3.9 to 8.1 %. However, break-even economic analysis indicated that the combination (SOYA) treatments evaluated had 0% probability of breaking across a wide range of yield levels and soybean prices, due to the high input costs. The foliar insecticide showed the highest probability of breaking even across a range of yield levels and crop prices (40% to 99%). Yield increases and breakeven probabilities were generally greatest in the northern states (Minnesota, Wisconsin, Michigan) and similar in the central and southern states. Lactofen application did not kill the apical meristem and had minimal effect on yield components compared to untreated soybeans at any growth stage. Meristem removal increased node m-2 in some environments, but did not increase pods m-2 and seeds m-2 or seed yield.
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Hitt, Lauren R., and Lars Tomanek. "ACUTE NITRATE EXPOSURE CAUSES PROTEOMIC CHANGES CONSISTENT WITH THE REGULATION OF REACTIVE OXYGEN AND NITROGEN SPECIES." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/95.
Full textAbstract:
Nitrate is the most common ionic form of nitrogen in aquatic ecosystems. Although nitrate is known to affect ecosystems at high levels through eutrophication, hypoxia and loss of biodiversity, it is considered to be physiologically inert to the individual aquatic organism. To test the physiological effects of nitrate on aquatic life, we exposed gill tissue of the Pacific oyster, Crassostrea gigas, to nitrate and characterized changes in protein expression, using a gel-based proteomics approach. Of the 642 protein spots detected, we found that 24 proteins (15 identified) changed expression in response to a 6-hour exposure to nitrate concentrations ranging from 0-73 mg/L, values that characterize highly contaminated surface and ground waters. Proteins changing expression included the oxidative stress proteins thioredoxin and cavortin (a member of the superoxide dismutase family) as well as proteins that are involved in G-protein signaling (Rho-GDI, ADP-ribosylation factor, G-protein ß-subunit), protein homeostasis (heat shock protein 70, prohibitin, calreticulin, and proteasome &#;-type 4 subunit), glycolysis (enolase), transport of hydrophobic molecules (lipocalin) and cytoskeletal arrangements (intermediate filaments and a gelsolin-like adseverin). The most parsimonious explanation for these changes in protein expression assumes that C. gigas reduces nitrate to nitrite and nitric oxide, which reacts with superoxide anions to form the very reactive peroxynitrite. We propose that part of the cellular response to reactive nitrogen species,phagocytic hemocytes inhibit the production of reactive oxygen species, potentially compromising the immune response of oysters to invading pathogens.
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Krjukova, Jelena. "Investigation on Pre- and Postsynaptic Ca2+ Signaling in Neuronal Model Systems." Doctoral thesis, Uppsala universitet, Institutionen för neurovetenskap, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4300.
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Communication between neuronal and non-neuronal is called volume transmission when the released neurotransmitter (NT) acts via diffusion and affects several target cells. Both the neurosecretory and postsynaptic cell responses are linked to [Ca2+]i elevations. In the present thesis the role of pre-and postsynaptic Ca2+ elevations has been investigated in the reconstituted "synapse" model comprised of NGF-differentiated PC12 and HEL cells as well as in SH-SY5Y neuroblastoma cells. In PC12 cells, both 70mM K+ and nicotine triggered NT release, which could be detected as a secondary [Ca2+]i increase in surrounding HEL cells. Both secretagogues shared the same voltage-dependent Ca2+ influx pathway as judged from the pharmacological profile blockers of voltage-gated Ca2+ channels. The coupling of electrical responses to the activation of Ca2+ signaling via muscarinic receptors in SH-SY5Y cells was also studied. These data revealed that depolarization caused a considerable potentiation of the muscarinic Ca2+ response. The potentiated Ca2+ increase was mainly dependent on the enhanced Ca2+ influx and to a lesser extent on [Ca2+]i release from intracellular stores. A phospholipase C (PLC) activator, m-3M3FBS was used to further study the role of G-protein coupled receptor (GPCR)-coupled Ca2+ signaling. However, it was found that m-3M3FBS instead triggered [Ca2+]i elevations independently of PLC activation. In conclusion, the results indicate that the magnitude of NT release from PC12 cells is sufficient to cause a robust activation of neighboring target cells. Postsynaptic muscarinic signaling is amplified due to integration of electrical excitation and GPCR signaling. The PLC activator, m-3M3FBS is not suitable for studies of PLC-mediated signals in intact cells.
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Walworth, James, David M. Kopec, Andrew Pond, and Jeff J. Gilbert. "Turfgrass Systems for Saline Irrigation Water." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009. http://hdl.handle.net/10150/216644.
Full textAbstract:
Seashore Paspalum (Paspalum vaginatum) is a warm-season halophyte with excellent salt tolerance after establishment. In areas which require overseeding, there is a need for a cool-season counterpart suitable for over-seeding. The goal of this field research is to evaluate a year-round turfgrass system for saline conditions using perennial ryegrass (Lolium perenne), alkaligrass (Puccinellia distans), and a combination of perennial ryegrass and Puccinellia as the cool-season grasses. In the summer months, paspalum quality and density were reduced when overseeded with ryegrass or with a combination of puccinellia and ryegrass. Ryegrass quality and density decreased slightly as irrigation water salinity was increased from 0 to 3000 to 6000 mg/L. In addition, the percentage of cover by overseeded ryegrass decreased significantly when 6000 mg/L irrigation water was applied. Puccinellia was much more sensitive to salinity than ryegrass and overall quality, turf density, and percent cover by puccinellia were greatly reduced by addition of salt. However, in the absence of added salt, puccinellia quality, percent cover, density, and color were generally greater than that of ryegrass. The puccinellia/ryegrass overseed mixture generally performed intermediate relative to either grass alone.
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Norton, E. R., and H. J. Borrego. "Evaluation of Envoke by Pix Interaction in Arizona Cotton Production Systems." College of Agriculture, University of Arizona (Tucson, AZ), 2006. http://hdl.handle.net/10150/198193.
Full textAbstract:
A single trial was conducted during the 2005 cotton growing season at The University of Arizona Safford Agricultural Center to evaluate the effects of the selective herbicide Envoke in combination and alone with the plant growth regulator (Pix). Combining applications of chemical inputs in a crop production system has the potential to help reduce costs by eliminating a trip across the field with equipment. The effects of these applications on growth, development, yield, and fiber quality was investigated. The trial was arranged with seven treatments including 1) control, 2) broadcast Envoke, 3) post-direct Envoke, 4) broadcast Pix, 5) broadcast Envoke + Pix, 6) post-direct Envoke followed by broadcast Pix, and 7) broadcast Pix followed by post-direct Envoke. These treatments were imposed in both normal and high soil moisture regimes. Plots were arranged in a randomized complete block design with four replications in two separate studies (normal and high soil moisture). Plots were monitored for effects on plant growth and development throughout the season by collecting a series of plant measurements from each treatment. Effects on final lint yield and fiber quality was determined by harvesting the center two rows of each four-row plot and weighing the resultant seed cotton. A sub-sample was collected for lint turnout and fiber quality analysis. Results indicated very little differences in plant growth and development among any of the treatments in both the normal and high moisture regimes. Significant differences were observed among lint yield and fiber quality parameters. Analysis of variance indicated significant effects due to treatment in lint yield, fiber length, strength, and uniformity. Significant differences were also observed due to soil moisture with respect to micronaire and fiber strength. Significant interaction between treatment and moisture regime was observed in micronaire, fiber length, strength, and uniformity. Results indicate that even though plant growth and development did not appear to be significantly impacted by the application of Pix + Envoke, lint yield was impacted. In both the normal and high soil moisture regimes the treatment receiving the combined application of Pix and Envoke produced the lowest yield.
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Norton, E. R., and H. J. Borrego. "Evaluation of Plant Growth Regulator Formulations in Arizona Cotton Production Systems." College of Agriculture, University of Arizona (Tucson, AZ), 2006. http://hdl.handle.net/10150/198211.
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A single experiment was conducted in 2005 at the University of Arizona Safford Agricultural Center in an effort to continue to evaluate several different formulations of the plant growth regulator (PGR) mepiquat chloride. Plots were established with the cultivar Deltapine DP 655BR on 19 April 2005. Four treatments were imposed on 18 July 2005 of 16 oz./acre applications of Mepex, Pix Ultra, and Pentia, plus a control plot. Plots were four 36” rows wide and extended the length of the irrigation run of 220 feet. Plots were arranged in a randomized complete block design with four replications. Plots were monitored with respect to plant growth and development through collecting plant measurement data over the course of the season. Yield results were obtained by harvesting the center two rows of each plot and weighing the resultant seedcotton. Fiber quality was determined from a sub-sample collected from each plot at harvest. Plant growth and development trends indicated strong fruit retention levels all season with strong early season vigor. Each of the PGR applications had significant impact on plant height effectively reducing internode elongation. Lint yield results indicated increased yields for all PGR applications over the control with Pentia producing a statistically significant higher yield. Fiber quality was also impacted by PGR application. All PGR treatments had trends toward higher staple length, fiber strength, and fiber uniformity. These results are consistent with previous results indicating that PGR applications have the potential to increase yields under situations were high vigor is present.
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Cordes, Henrik [Verfasser], Lars Mathias [Akademischer Betreuer] Blank, and Rodríguez Julio [Akademischer Betreuer] Sáez. "Multi-scale modeling in human systems pharmacology & physiology / Henrik Cordes ; Lars Mathias Blank, Julio Sáez Rodríguez." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1194066887/34.
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Tegge, Samuel. "The Mechanism of Biotremor Production in the Veiled Chameleon (Chamaeleo calyptratus)." TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/2336.
Full textAbstract:
Vibratory communication has evolved in numerous animal groups, including insects, spiders, fishes, mammals, and was recently discovered in veiled chameleons (Chamaeleo calyptratus). I examined the mechanism by which C. calyptratus produce these biotremors. Muscle activity data were gathered during simulated anti-predator responses via electromyography (EMG) with simultaneous recordings of biotremor production using an accelerometer. I correlated EMG data with the accelerometer data to implicate the muscles responsible for the production of the biotremors. Mixed-effect linear regression models described the mechanism, and a model selection framework determined which model fit the data best. I then used an analysis of variance to partition the variance to each variable to determine which muscles were most important in the biotremor producing mechanism. The Mm. sternohyoideus superficialis et profundus, Mm. mandibulohyoideus, and M. levator scapulae were active during the production of biotremors. Mean latency calculations revealed that the M. levator scapulae and Mm. mandibulohyoideus activated prior to the vibration onset, and the Mm. sternohyoideus superficialis et profundus activated after the vibration onset. The M. sternohyoideus superficialis then ceased activity prior to vibration cessation, and the M. sternohyoideus profundus, Mm. mandibulohyoideus, and M. levator scapulae ceased activity after the vibration had ended. The description of the biotremor producing mechanism further supports that C. calyptratus can produce biotremors, possibly for communication.
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Bohara, Gyanendra. "Application of Statistical Physics in Human Physiology: Heart-Brain Dynamics." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1248449/.
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This dissertation is devoted to study of complex systems in human physiology particularly heartbeats and brain dynamics. We have studied the dynamics of heartbeats that has been a subject of investigation of two independent groups. The first group emphasized the multifractal nature of the heartbeat dynamics of healthy subjects, whereas the second group had established a close connection between healthy subjects and the occurrence of crucial events. We have analyzed the same set of data and established that in fact the heartbeats are characterized by the occurrence of crucial and Poisson events. An increase in the percentage of crucial events makes the multifractal spectrum broader, thereby bridging the results of the former group with the results of the latter group. The crucial events are characterized by a power index that signals the occurrence of 1/f noise for complex systems in the best physiological condition.
These results led us to focus our analysis on the statistical properties of crucial events. We have adopted the same statistical analysis to study the statistical properties of the heartbeat dynamics of subjects practicing meditation. The heartbeats of people doing meditation are known to produce coherent fluctuations. In addition to this effect, we made the surprising discovery that meditation makes the heartbeat depart from the ideal condition of 1/f noise.
We also discussed how to combine the wave-like nature of the dynamics of the brain with the existence of crucial events that are responsible for the 1/f noise. We showed that the anomalous scaling generated by the crucial events could be established by means of a direct analysis of raw data. The efficiency of the direct analysis procedure is made possible by the fact that periodicity and crucial events is the product of a spontaneous process of self-organization. We argue that the results of this study can be used to shed light into the nature of this process of self-organization.
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Norton, E. R., and H. Borrego. "Evaluation of Commercial Harvest Aid Products in Arizona Upland Cotton Production Systems." College of Agriculture, University of Arizona (Tucson, AZ), 2006. http://hdl.handle.net/10150/198210.
Full textAbstract:
A defoliation experiment was conducted during the 2005 growing season in an effort to evaluate effectiveness of the Ginstar™ defoliant alone and in combination with Cotton Quick™. This study was conducted at the University of Arizona Safford Agricultural Center on Upland (cultivar DP655BR). Plots were planted on 22 April. Treatments were arranged in a randomized complete block design with four replications and treatments that included Ginstar™ at 6 and 8 oz./acre rates and Ginstar™ at the 6 and 8 oz./acre rates in combination with various rates of Cotton Quick™ (1.5, 2, 3, and 4 pts/acre). A control, not receiving any harvest prep material was also included for a total of eleven treatments. Treatments were imposed on 3 October and evaluations were made on 14 October and 26 October. Estimations on percent leaf drop, regrowth control, and open boll were made. Lint yield was estimated by harvesting the center two rows of each plot and sub-samples were collected for fiber quality analysis. Plots were harvested on 26 October in an attempt to evaluate the boll opening effectiveness of the Cotton Quick™ material. Results indicated increased leaf drop in lower Ginstar™ rates with the addition of Cotton Quick™. Measurements of open boll percentages did not indicate any increase with the addition of Cotton Quick™ however, lint yield and fiber quality parameters would demonstrate otherwise. Lint yield slightly increased in all treatments receiving Cotton Quick™ while fiber micronaire decreased in Cotton Quick™ treatments. This would indicate a blending of less mature bolls opened with the addition of Cotton Quick™ with those already opened. Percent lint also increased in all treatments receiving Cotton Quick™.
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Norton, E. R., and D. L. Hatch. "2006 Evaluation of Commercial Harvest Aid Materials in Arizona Cotton Production Systems." College of Agriculture, University of Arizona (Tucson, AZ), 2007. http://hdl.handle.net/10150/198216.
Full textAbstract:
A defoliation experiment was conducted during the 2006 growing season in an effort to evaluate the effectiveness of Ginstar® and FreeFall® defoliant alone and in combination with CottonQuik®. This study was conducted at the University of Arizona Safford Agricultural Center on Upland (cultivar DP655BR). Plots were planted on 20 April. Treatments were arranged in a randomized complete block design with four replications and treatments included Ginstar® at 6 and 8 oz./acre rates and Ginstar® at the 6 and 8 oz./acre rates in combination with various rates of CottonQuik® (1.5, 2, 3, and 4 pts/acre). We also evaluated a new product from DuPont, FreeFall® SC at different rates (3.2, 4.8, 6.4 oz./acre) in combination with CottonQuik® (2 pts./acre). The standard defoliation protocol among growers in southeastern Arizona is sodium chlorate plus Gramoxone®, so this treatment combination was also included. A control, not receiving any harvest prep material was also included for a total of fifteen treatments. Treatments were imposed on 13 October and evaluations were made on 20 October and 1 November. Estimations on percent leaf drop, regrowth control, and open boll were made. Lint yield was estimated by harvesting the center two rows of each plot and sub-samples were collected for fiber quality analysis. Plots were harvested on 2 November directly after the second evaluation date in an attempt to evaluate the boll opening effectiveness of the CottonQuik® material. Results indicated higher effectiveness of leaf drop or defoliation in the plots that included CottonQuik® as opposed to Ginstar® alone. The treatments performed much better that the standard sodium chlorate treatment. Percent leaf drop also increased at the higher rates of FreeFall® (4.8, 6.4 oz./acre). The percentage of open boll was also improved with the addition of CottonQuik® to the all of the treatments. However, very little significant differences were observed in lint yield and fiber quality. A trend of increased yield with the addition of CottonQuik® was observed when compared to Ginstar® alone or the standard sodium chlorate treatment. All aspects of harvest preparation including percent defoliation and boll opening appear to be significantly enhanced with the use of CottonQuik® when compared to standard Ginstar® rates alone.