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1
Watkins, Adam Christopher. "RADIATION INDUCED TRANSIENT PULSE PROPAGATION USING THE WEIBULL DISTRIBUTION FUNCTION." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/811.
Повний текст джерелаАнотація:
In recent years, studying soft errors has become an issue of greater importance. There have been many methods developed that estimate the Soft Error Rate. Those methods are either deterministic or statistical. The proposed deterministic model aims to improve Soft Error Rate estimation by accurately approximating the generated pulse and all subsequent pulses. The generated pulse is approximated by a piecewise function consisting of two Weibull cumulative distribution functions. This method is an improvement over existing methods as it offers high accuracy while requiring less pre-characterization. The proposed algorithm reduces pre-characterization by allowing the beta Weibull parameter to be calculated during runtime using gate parameters such as the gate delay.
2
Katisart, Teeraporn. "Transient receptor potential function in bladder from control and streptozotocin treated rats." Thesis, University of Hertfordshire, 2011. http://hdl.handle.net/2299/6039.
Повний текст джерелаАнотація:
Diabetic cystopathy is a chronic and common complication of diabetes with a classical triad of symptoms; decreased bladder sensation, increased bladder capacity and impaired detrusor muscle contractility (Hunter and Moore, 2003). In animal models of diabetes such as streptozotocin-induced diabetes in the rat, abnormalities of bladder function have been reported (Longhurst and Belis, 1986). The prototypic TRPV channel, TRPV1, is activated by capsaicin, which has been shown to cause contraction of the rat bladder (Saitoh et al., 2007), and this is reduced in STZ-diabetic rat bladder (Pinna et al., 1994). Therefore we hypothesize that TRPV1 function will be reduced in the diabetic bladder. The aim of this study are the following: Firstly, to investigate the effect of the streptozotocin (STZ) model of diabetes on a range of TRP channel functions in the urinary bladder smooth muscle preparation using TRP channel agonists and antagonists and to study the neurotransmitters involved in the contractile or relaxant responses. Some studies were also performed on colon tissues. Secondly, to explore the involvement of cholesterol modudation in TRP channel signalling. Thirdly, to study the change in TRP channel response with time following the treatment with streptozotocin. The results showed that the contractile responses to the TRPV1 agonist capsaicin, TRPV4 agonist 4-α-PDD, and TRPA1 agonist allyl isothiocyanate were significantly reduced in diabetic bladder. The selective TRPV1 antagonist, SB-366791, inhibited the contractile responses to capsaicin confirming the involvement of TRPV1 channels. The effect of diabetes is unlikely to be at the level of contractile machinery since the contractile responses to muscarinic receptor agonist carbachol were not significantly reduced in diabetic tissues. It is reported for the first time that the combination of neurokinin 1 and 2 antagonists GR-205171 and SB-207164 inhibited the contractile responses to capsaicin suggesting that a neurokinin may be the neurotransmitter involved in the capsaicin responses. In addition, the reduction of the responses to capsaicin in STZ-induced diabetic tissues occurred not only in urinary bladder but also in colon. Cholesterol-PEG significantly lowered the maximal contractile responses to capsaicin of rat bladder strips. Methyl-β-cyclodextrin, α-cyclodextrin and β-cyclodextrin at the same concentrations enhanced the contractile responses to capsaicin in the control and diabetic rat bladder strips. These effects of cyclodextrin are specific to capsaicin activated contractions and not seen with TRPA1 activation, suggesting that the effects are not mediated downstream of channel activation. Since α-cyclodextrin does not sequester cholesterol, the enhanced responses to cyclodextrins may not be due to the cholesterol modulations. Instead, theses novel findings may possibly occur by changing the local membrane lipid environment of the TRPV1 channel. As early as 36 hours after induction of diabetes by STZ, the contractile responses to capsaicin were significantly reduced in comparison to those of the controls and this reduction persisted until the eight weeks time point. In contrast, responses to the TRPA1 agonist allyl isothiocyanate were not affected at early time points but were reduced one week after STZ treatment. This detailed time course analysis suggests that there are novel mechanisms of modulation of the TRPV1 channels in this STZ model. In conclusion, in the rat urinary bladder or colon preparations, diabetes mellitus using STZ animal model caused 1) the impairment of a number of TRP channel subfamily functions, TRPV1, TRPV4 and TRPA1 but not TRPM8. The combination of NK1 and NK2 antagonists significantly inhibited the responses to capsaicin. This may suggest the involvement of neurokinin in postsynaptic transmission in rat bladder following the activation of TRPV1 channel, 2) the impairment caused by STZ-induced diabetes occurred very early (within 36 hours after diabetes induction) in TRPV1 channel but not TRPA1 channel. There are specific early effects of STZ treatment on TRPV1 channel function at a time when other afferent nerve terminal channels (TRPA1) are functioning normally, suggesting that early onset of dysfunction in TRPV1 signalling may not merely be the consequence of nerve damage, 3) the mechanism of this impairment may not be the effect of neuropathy on neurotransmitter release or nerve damage. Improving the responsiveness of nerves of bladder in diabetic patients might be of therapeutic benefit. The present studies suggest that it is possible to enhance function using indirect modulators such as bradykinin which potentiated the TRPV1 channel function in diabetic rat bladders.
3
陳偉樂 and Wai-lok Chan. "Multi-function monitoring system for harmonic and transient study of power networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B31210727.
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4
Chan, Wai-lok. "Multi-function monitoring system for harmonic and transient study of power networks /." [Hong Kong : University of Hong Kong], 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13418051.
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5
Zettner, Erika Maria. "Transient otoacoustic emission suppression tuning curves as a function of psychophysical threshold /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8273.
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6
Myers, Benjamin R. "Genetic and evolutionary approaches to transient receptor potential channel structure and function." Diss., Search in ProQuest Dissertations & Theses. UC Only, 2008. 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:3339199.
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7
Mellechervu, Karthik. "Modeling of Transient Thrust of a Two Phase Propellant Tank." Cleveland State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1231561130.
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8
Shaner, Samuel Christopher. "Transient method of characteristics via the Adiabatic, Theta, and Multigrid Amplitude Function methods." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92092.
Повний текст джерелаАнотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2014.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 147-149).<br>In this thesis, we investigated the Adiabatic, Theta, and Multigrid Amplitude Function (MAF) methods for solving the Method of Characteristics (MOC) formulation of the time-dependent neutron transport equation. The transient transport versions of the 2D LRA and C5G7 benchmarks were used to assess the performance and accuracy of these methods. We began by deriving the CMFD-accelerated MOC algorithm in 2D steady state form and examining the effects of various MOC and CMFD parameters on eigenvalue convergence. The C5G7 problem showed similar acceleration performance for 2, 4, and 7 CMFD energy group structures. CMFD meshes at or near the pin-cell level resulted in the greatest speedups of 15-45x in run time and 30-240 x in number of MOC iterations for both problems. A relaxation factor on the nonlinear diffusion coefficient was required to maintain stability for both problems with optimum values between 0.4-0.7. A sensitivity study was conducted on the C5G7 and LRA transient problems to understand the effects of time step and spatial mesh sizes on the solution accuracy and run time performance. The shape function time step size had a large effect on the solution accuracy for the MAF and Theta methods in solving the LRA problem. All methods showed moderate sensitivity to the amplitude function step size, where increasing step size shifted the peak power to earlier times. The coarse mesh size did not have a significant effect on solution accuracy, but meshes on the pin-cell level were clearly preferred to reduce run time. The overall run time performance between the three methods was mixed. The MAF and Theta methods displayed ~84% speedup over the Adiabatic method for the LRA problem, but all methods had similar run times for the C5G7 problem. This inconsistency is likely due to the more drastic flux shape change during the LRA transient and the ability of the MAF and Theta methods to more accurately treat the flux shape temporal derivative. These results demonstrate that the Adiabatic, Theta, and MAF methods are computationally efficient methods for solving the time-dependent neutron transport equation and warrant further investigation. There are clear advantages to each method and the optimal method will likely depend on the transient characteristics of the problem being studied.<br>by Samuel Christopher Shaner.<br>S.M.
9
Waldenborg, Micael. "Echocardiographic measurements at Takotsubo cardiomyopathy : transient left ventricular dysfunction." Doctoral thesis, Örebro universitet, Institutionen för hälsovetenskap och medicin, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-35798.
Повний текст джерелаАнотація:
Takotsubo cardiomyopathy (TTC) is a disease characterized by transient left ventricular (LV) dysfunction and typical wall motion abnormalities in apical parts, without obvious signs of coronary influence. Due to its elusive natural cause and the lack of clarified pathology, further studies are needed. Thirteen patients presented with an episode of TTC, and referred to Örebro University Hospital (USÖ), were prospectively included and investigated by comparisons made at onset (acute phase) against at follow-up three months later (recovery phase). Including echocardiographic measurements, focused on biventricular systolic long-axis function and conventional diastolic function (DF) variables. Systolic improvement was shown, while most DF data were unchanged, suggesting that TTC is mainly a systolic disease affecting both ventricles. Diagnosis should include multidisciplinary engagement, as TTC associates both with emotional stress and pathological markers of physiological stress. In this thesis, such approach was offered to the aforementioned patients; to see if a common denominator could be found, thus, contributing to better handling. Emotional state was assessed, along with an array of cardiac investigations in addition to echocardiography. Acutely, imbalance in the autonomic cardiac control was shown, as well as a trend toward posttraumatic stress, but specific findings allowing conclusions on differential diagnosis could not be demonstrated. By adding another 15 TTC patients (i.e. 28 in total), through collaboration with observers from USA, a retrospective echocardiographic analysis could be done to further study DF; concluding that TTC associates with impairment of conventional DF variables which tends to parallel the systolic recovery, in contrary to the initial result but in line with other causesof LV dysfunction. Magnetic resonance imaging (MRI) is another method of choice at TTC. The USÖ patients had cardiac MRI, thus, a retrospective analysis was done to investigate the effect on LV geometry, both echocardiographic and by MRI; suggesting that TTC is consistently associated with increased LV mass, due to a local impact that seems to follow the change in LVconcentric wall motion.
10
Al, Marhoon Hussain Hassan. "A Practical Method for Power Systems Transient Stability and Security." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/114.
Повний текст джерелаАнотація:
Stability analysis methods may be categorized by two major stability analysis methods: small-signal stability and transient stability analyses. Transient stability methods are further categorized into two major categories: numerical methods based on numerical integration, and direct methods. The purpose of this thesis is to study and investigate transient stability analysis using a combination of step-by-step and direct methods using Equal Area Criterion. The proposed method is extended for transient stability analysis of multi machine power systems. The proposed method calculates the potential and kinetic energies for all machines in a power system and then compares the largest group of kinetic energies to the smallest groups of potential energies. A decision based on the comparison can be made to determine stability of the power system. The proposed method is used to simulate the IEEE 39 Bus system to verify its effectiveness by comparison to the results obtained by pure numerical methods.
11
Smith, Peter Alan. "A study of the transient effects of high energy laser light on visual function." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243277.
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12
Kim, Jeong-Han. "Optical display of the Airy function and transient wave propagation in a dispersive medium." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-02132009-172038/.
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13
Ralphs, Katherine L. "Characterisation of the localisation and function of the mammalian transient receptor potential channel seven." Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415762.
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14
Du, Xiaoyu. "PLAGL1/ZAC, a transient neonatal diabetes mellitus locus gene, in pancreatic beta-cell development and function." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=96741.
Повний текст джерелаАнотація:
Studies on congenital disorders of the pancreas have contributed to the identification of genes that are critical in beta-cell development and function. Transient neonatal diabetes mellitus (TNDM) is a rare congenital disorder of the pancreas. It involves severe insulin deficiency at birth that reverses over weeks or months but may relapse with diabetes in later life. PLAGL1 (pleiomorphic adenoma gene-like 1, also known as ZAC, zinc finger protein that regulates apoptosis and cell cycle arrest, and LOT1, Lost On Transformation 1) is one of the two possible genes at the TNDM locus and the multiple functions of PLAGL1/ZAC strongly suggest it as the causative gene of TNDM. We hypothesized that double dose expression of PLAGL1/ZAC impairs both beta-cell development and function. To test this hypothesis, we began with the study of ZAC ontogeny. In developing human pancreas, ZAC is expressed with considerable specificity in differentiated beta-cells, and its expression decreases dramatically from the second trimester to adult. These results imply a role of ZAC in a critical time window in beta-cell development, supporting its role in TNDM and explaining the transient nature of the TNDM. In vitro, effects of ZAC overexpression on beta-cell function was observed in INS-1 cells by using tetracycline regulatable system. Overexpression of ZAC inhibits glucose-stimulated insulin exocytosis and proinsulin biosynthesis. Glucose was found to be able to downregulate Lot1/Zac1 expression in INS-1 cells and mouse islets. These data suggest ZAC as a negative regulator in some glucose-regulated pathways whose abnormally high level impairs beta-cell function that explains the relapse of diabetes in TNDM. Finally, a gene expression profile study of INS-1 cells with or without induced ZAC expression identified STC1, IGF1R, SNAP25, GRP78, and P58IPK as possible targets of ZAC that mediate beta-cell dysfunctions. CRABP2, strongly upregulated by ZAC, together with G0S2, GADD45alpha, and FHL2, may mediate ZAC function in both normal beta-cell development and TNDM pathophysiology. In general, these studies suggest that tightly controlled expression level of ZAC is critical for beta-cell development and function. It provides strong evidence that ZAC overexpression causes TNDM. In addition, two previously unstudied genes, STC1 and CRABP2, are suggested to play potential important roles in beta-cell function and development.<br>Les études portant sur les désordres congénitaux du pancréas ont contribué à l'identification de gènes critiques pour le développement et la fonction des cellules bêta. Le diabète néonatal transitoire (DNNT) est une maladie héréditaire du pancréas. Elle est caractérisée par une déficience sévère en insuline à la naissance qui disparaît après quelques semaines/mois mais pouvant réapparaître plus tard au cours de la vie. PLAGL1 (pleiomorphic adenoma gene-like 1, aussi connu comme ZAC, zinc finger protein that regulates apoptosis and cell cycle arrest, et LOT1, Lost On Transformation 1) est un des deux gènes dans la région critique du DNNT et ses multiples fonctions en font le candidat causatif le plus probable. Notre hypothèse est que sa surexpression compromet la fonction et le développement des cellules bêta. Notre étude ontgénique de ZAC dans le pancréas en développement, démontre que ZAC était exprimé avec une spécificité considérable dans les cellules bêta, expression qui diminuait à partir du second trimestre. Ces résultats supportent l'existence d'une fenêtre temporelle critique pour la fonction de ZAC dans le développement des cellules bêta, compatible avec la nature transitoire du DNNT. In vitro, les effets de la surexpression de ZAC ont été observés dans les cellules bêta INS-1 en utilisant un système d'expréssion inductible par la tétracycline. L'exocytose glucose-dépendante de l'insuline et la biosynthèse de la proinsuline sont diminués par la surexpression de ZAC. Le glucose pouvait diminuer l'expression de Lot1/Zac1 dans les INS-1 et dans les îlots murins, une observation qui propose ZAC comme un régulateur négatif de voies métaboliques régulées par le glucose dont les niveaux anormalement élevés affectent la fonction des cellules bêta. Le profile d'expression génique sur les INS-1 après induction de ZAC a identifié STC1, IGF1R, SNAP25, GRP78 et P58IPK comme cibles potentielles de ZAC intervenant dans les dysfonctionnements des cellules bêta. CRABP2, qui est fortement augmenté, tout comme G0S2, GADD45alpha et FHL2, pourrait servir de médiateur de ZAC dans le développement des cellules bêta et dans le DNNT. Ces études indiquent qu'une expression minutieusement contrôlés de ZAC est critiques pour le développement et la fonction des cellules bêta et que sa surexpression peut causer le DNNT. Finalement, un rôle de STC1 et CRABP2 dans la fonction et le développement des cellules bêta est suggéré.
15
Xie, Yicheng. "Optogenetic investigation of neuronal excitability and sensory-motor function following a transient global ischemia in mice." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55954.
Повний текст джерелаАнотація:
Global ischemia occurs during cardiac arrest and has been implicated as a complication that can occur during cardiac surgery. It induces delayed neuronal death in human and animal models, particularly in the hippocampus, while it also can affect the cortex. Other than morphology and measures of cell death, relatively few studies have examined neuronal networks and motor-sensory function following reversible global ischemia in vivo. Optogenetics allows the combination of genetics and optics to control or monitor cells in living tissues. Here, I adapted optogenetics to examine neuronal excitability and motor function in the mouse cortex following a transient global ischemia. Following optogenetic stimulation, I recorded electrical signals from direct stimulation to targeted neuronal populations before and after a 5 min transient global ischemia. I found that both excitatory and inhibitory neuronal network in the somatosensory cortex exhibited prolonged suppression of synaptic transmission despite reperfusion, while the excitability and morphology of neurons recovered rapidly and more completely. Next, I adapted optogenetic motor mapping to investigate the changes of motor processing, and compared to the changes of sensory processing following the transient global ischemia. I found that both sensory and motor processing showed prolonged impairments despite of the recovery of neuronal excitability following reperfusion, presumably due to the unrestored synaptic transmission. Interestingly, motor processing recovered faster and more completely than sensory processing. My results suggest a uniform suppression of synaptic transmission, both in excitatory and inhibitory network, despite the rapid recovery of neuronal excitability and morphology, following a global ischemia and reperfusion. This prolonged suppression of synaptic transmission might impede the recovery of sensory and motor processing with differential severity. Besides, I extended tools for mesoscopic imaging using novel optogenetic sensors, including genetically encoded Ca2+ indicators - GCaMPs, and extracellular glutamate sensor - iGluSnFR. I found that iGluSnFR has fastest kinetics for reporting both sensory and spontaneous activity in the cortex, which can resolve temporal features of sensory processing that were not readily observed with GECIs. I suggest that iGluSnFR tools have potential utility in normal physiology, and neurologic pathologies in which abnormalities in glutamatergic signaling are implicated, such as stroke.<br>Medicine, Faculty of<br>Graduate
16
Al, Marhoon Hussain Hassan. "Adaptive Online Transient Stability Assessment of Power Systems for Operational Purposes." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2036.
Повний текст джерелаАнотація:
Online stability assessment is an important problem that has not been solved completely yet. The purpose of this research is to tackle online transient stability assessment. Currently, most utility companies use step-by-step integration in order to set protective equipment so that they effectively work for critical contingencies. However, there are times an unforeseen contingency may occur which may cause the system to transit and the protective equipment to misoperate and does not isolate the disturbed part of the system. This research introduces a method that automatically determines a group of generators that participate in system separation and hence transient instability. The method consists of four phases: modeling and simulation, critical machines identification, online transient stability assessment, and critical clearing time calculation. In the modeling and simulation phase, the power system is built and the generators’ rotor angles and speeds are captured. In the critical machines identification phase, the average instantaneous rotor accelerating powers, coherency measures, the during-fault rotor angles and speeds characteristics, and the pre- and post-fault rotor angles are used to identify the Severely Disturbed Group (SDG) of machines. The results of this phase are used to calculate the kinetic energy of the SDG and potential energy of another (or possibly the same) group of generators. Utilization and success of the proposed method will be documented using results from the IEEE 39-Bus test system. Each step of each phase will be demonstrated as needed. The proposed method is compared to step-by-step integration and two direct methods. The suitability of the proposed method for operation will be shown in cases where the Y-Bus matrix and rotor angles and speeds are given. The proof of concept of the proposed method was used in simulating the test system and encouraging results of the simulation were published in [1] and [2]. The proof of concept is the foundation of the method proposed in this dissertation to determine transient stability of large-scale power systems.
17
Yevseienko, Oleg, Anatoliy Gapon, and Dmytro Salnikov. "Searching for Optimal Control Parameters of Thermal Object Using Pulse-Width Modulation (PWM) Control with Predictive Filter." Thesis, Lviv Polytechnic Publishing House, 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41116.
Повний текст джерелаАнотація:
The thesis is devote to the temperature control of objects with lumped or distributed parameters. The problems of choosing the right value of regulator’s heater power and prediction period are discussed. The major attention is paid to the process of searching the minimum value of control quantities. It is shown that the approximated second-order plane has an exact accordance with the original data. It is concluded that algorithm of PWM-control with prediction filter provides good quality control.
18
Latorre, Hector. "Modeling and Control of VSC-HVDC Transmissions." Doctoral thesis, KTH, Elektriska energisystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32313.
Повний текст джерелаАнотація:
Presently power systems are being operated under high stress level conditions unforeseen at the moment they were designed. These operating conditions have negatively impacted reliability, controllability and security margins. FACTS devices and HVDC transmissions have emerged as solutions to help power systems to increase the stability margins. VSC-HVDC transmissions are of particular interest since the principal characteristic of this type of transmission is its ability to independently control active power and reactive power. This thesis presents various control strategies to improve damping of electromechanical oscillations, and also enhance transient and voltage stability by using VSC-HVDC transmissions. These control strategies are based of different theory frames, namely, modal analysis, nonlinear control (Lyapunov theory) and model predictive control. In the derivation of the control strategies two models of VSC-HVDC transmissions were also derived. They are Injection Model and Simple Model. Simulations done in the HVDC Light Open Model showed the validity of the derived models of VSC-HVDC transmissions and the effectiveness of the control strategies. Furthermore the thesis presents an analysis of local and remote information used as inputs signals in the control strategies. It also describes an approach to relate modal analysis and the SIME method. This approach allowed the application of SIME method with a reduced number of generators, which were selected based on modal analysis. As a general conclusion it was shown that VSC-HVDC transmissions with an appropriate input signal and control strategy was an effective means to improve the system stability.<br>QC 20110412
19
McCabe, Dominick John Henry. "Assessment of platelet activation and function in ischaemic stroke, transient ischaemic attack and asymptomatic severe caratid stenosis." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406355.
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20
Payn, Robert Alden. "The Geomorphic Influence of Agricultural Land Use on Stream Hydraulics and Biological Function." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/33913.
Повний текст джерелаАнотація:
<p>Agricultural land use near streams frequently results in long-term disturbance to woody riparian vegetation and an alteration of reach scale geomorphic structure. Such disturbances often result in increased fine sediment input to the stream along with direct changes in channel structure. The study described here was designed to quantify stream geomorphic changes associated with agriculture and their influence on reach scale transient storage hydraulics and sediment biological function. Six small streams in the Appalachian Mountains of western North Carolina were selected to compare 3 reaches with active near-stream agriculture to 3 forested reference reaches. The study site categories differed significantly in many structural and hydraulic properties including slope, sinuosity, sediment size, and transient storage extent. However, differences cannot be attributed to land use alone. Distinct disparity in slope suggests that many of the categorical differences between stream types may also reflect valley scale structure. Despite these larger scale controls, the abundance of suspendable fines varied substantially among agricultural stream substrates, possibly due to varied land-use practices. Suspendable fine sediments and valley slope explained 91 % of variability in transient storage exchange, and abundance of inorganic fine sediments explained 77 % of variability in sediment microcosm nitrate production. This study supports conclusions that reach-scale influence of fine sediments occurred within the context of larger-scale valley structure, with implications on stream hydraulics and biogeochemistry.</p><br>Master of Science
21
Stott, Iain Michael. "Modelling transient population dynamics and their role in ecology and evolution." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/3733.
Повний текст джерелаАнотація:
Population projection matrix (PPM) models are a central tool in ecology and evolution. They are widely used for devising population management practises for conservation, pest control, and harvesting. They are frequently employed in comparative analyses that seek to explain demographic patterns in natural populations. They are also a key tool in calculating measures of fitness for evolutionary studies. Yet, demographic analyses using projection matrices have, in some ways, failed to keep up with prevailing ecological paradigms. A common focus on long-term and equilibrium dynamics when analysing projection matrix models fits better with the outmoded view of ecosystems as stable and immutable. The more current view of ecosystems as dynamic and subject to constant extrinsic disturbances has bred new theoretical advances in the study of short-term "transient" dynamics. Transient dynamics can be very different to long-term trends, and given that ecological studies are often conducted over short timescales, they may be more relevant to research. This thesis focuses on the study of transient dynamics using population projection matrix models. The first section presents theoretical, methodological and computational advances in the study of transient dynamics. These are designed to enhance the predictive power of models, whilst keeping data requirements to a minimum, and borrow from the fields of engineering and systems control. Case studies in this section provide support for consideration of transient dynamics in population management. The second section applies some of these new methods to answer pertinent questions surrounding the ecology and evolution of transient dynamics in plants. Results show that transient dynamics exhibit patterns according to life form and phylogenetic history. Evidence suggests that this can be linked to the stage-structuring of life cycles, which opens up the possibility for new avenues of research considering the evolution of transient dynamics in nature.
22
Chin, Reiko. "Effects of Exercise Training on Myocardial Fatty Acid Metabolism in Rats with Depressed Cardiac Function Induced by Transient Ischemia." Kyoto University, 2001. http://hdl.handle.net/2433/150165.
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Kundrotienė, Jurgita. "Ischemic brain damage following transient and moderate compression of sensorimotor cortex in Sprague-Dawley and diabetic Goto-Kakizaki rats /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7349-819-X/.
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Anandarajan, Mugilan. "The expression and function of airway epithelial Transient Receptor Potential (TRP) channels in hypersensitive airways in children with respiratory problems." Thesis, Queen's University Belfast, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.725331.
Повний текст джерелаАнотація:
Aim' To determine whether the bronchial epithelial cells from young children with different wheezing or coughing phenotypes have increased expression of transient receptor potential (TRP) cation channel receptors compared to normal. Hypotheses to be tested: TRPV1, TRPV4, TRPA1 and TRPM8 receptors are expressed and over-expressed on the bronchial epithelium of young children with post bronchiolitis wheezing / episodic viral induced wheezing (non- asthmatic wheezers), classical atopy asthma and coughers compared to normal subjects. Methodology: Freshly isolated bronchial epithelial cells from children were tested for expression of TRP channels and their functional role by microfluorimetry, immunocytochemistry, confocal live cell imaging, patch clamping and qt- PCR. Results: The experiments conducted in the present study has aided in inferring that TRPV1, V4, A1 and M8 channels are expressed and are functional in bronchial epithelial cells. The channels are expressed in sub cellular organelles in the peri nuclear and nuclear region and are involved in calcium signaling. Our data from microfluorimetry and confocal live cell experiments strongly suggests that TRPM8, V1, V4 and A1 channels are functionally active as evidenced by their ability to 2+ contribute to PBEC Ca signaling and there were differences in response of freshly isolated bronchial epithelial cells between asthmatic and healthy children. However further tests needed to be carried out with more patient samples to analyze the significance of the differences. The analysis of responses from confocal live cell imaging suggested that the calcium whole cell responses and the peak responses in microfluorimetry experiments were increased in most asthmatic cells in comparison to Freshly isolated bronchial epithelial cells from healthy children. Despite the number of patient samples and cells analyzed this is a significant finding suggesting possible up regulation or over expression of the TRP channels in children with asthma. The present study has shown the presence of TRPV1, V4, A1 and M8 channels in bronchial epithelium with possible increased expression or upregulation of these channels in asthma compared to normal healthy children.
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Fang, Fang. "Gain-of-function mutations in SCN5A gene lead to type-3 long QT syndrome." Cleveland State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=csu1354056382.
Повний текст джерела
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Briceno, Jose Alejandro. "Analysis of the Generation of Auditory Steady-State Cortical Evoked Responses in Guinea Pigs." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_theses/146.
Повний текст джерелаАнотація:
Recent research shows that human auditory steady-state responses (ASSRs) develop a resonance at 40 Hz and the dramatic amplitude increase of the Pb component of the middle latency response (MLR) accounts for the high amplitude of the ASSR at 40 Hz. The first part of this study aimed to investigate the ASSR resonance characteristics as a function of rate in guinea pigs. A study of the grand average of the peak-to-peak and fundamental frequency amplitudes does indeed show a resonance around 40 Hz in guinea pigs. Unlike human ASSRs, this resonance is very broad (26-52 Hz) and flat. The centrally recorded ASSRs are smaller and tend to have resonances at higher rates compared to temporal signals. The second part of the analysis investigated whether the superposition of transient responses can predict the acquired ASSRs at each corresponding rate. This superposition theory is one of two competing theories on the origin of the ASSRs, with the other centering on the induced phase synchronization of brain waves. In order to test the first theory, transient responses were used to create synthetic ASSRs, which were then compared to the acquired ASSRs via correlation coefficient and phasor analysis. For the 40 Hz ASSR, both temporal and central electrode synthesized ASSRs show a correlation coefficient above 0.80. In the comparison at 20 Hz, the correlation coefficient is very high (about 0.9) in the temporal electrode, yet significantly lower (about 0.7) for the central electrode. Furthermore, at 80 Hz, the correlation coefficient is significantly lower in both temporal and central electrodes (about 0.7). At all rates, the correlation coefficients are highest with low jitter sequences. Finally, phasor analysis was also used to test the superposition theory of the generation of the acquired ASSRs at 20, 40, and 80 Hz. Overall, in the temporal recordings at 40 Hz, the superposition of the MLR responses accurately predicted the acquired 40 Hz ASSR as demonstrated by both magnitude and phase analysis. The recordings made in the central electrode only predicted the acquired ASSR in its phases, with significant differences found in magnitude at its main harmonics. Similarly, at 20 and 80 Hz in both temporal and central electrodes, the synthetic ASSRs did not appear to fully predict the acquired ASSRs. Although the phases were successfully predicted, large magnitude variations were observed. As shown by mean prediction error plots, the acquired ASSRs are best predicted by low jitter sequences, followed by low-medium and medium jitter sequences.
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Cuceoglu, Faik. "An Experimental Study on Soil Water Characteristics and Hydraulic Conductivity of Compacted Soils." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73673.
Повний текст джерелаАнотація:
The importance of applying unsaturated soil mechanics concepts to geotechnical engineering design has been widely recognized. Soil water characteristic curve (SWCC) and hydraulic conductivity function (HCF) are vital soil properties that govern engineering behavior of unsaturated soils. In this study, a transient water release and imbibitions method (TRIM) is used to measure the SWCC and HCF under drying and wetting states, which accommodates integrated experimental and modeling techniques. The results of saturated hydraulic conductivity tests through flexible wall method are then used as input parameters for simulating experimental data. In general, the model provides a satisfactory fit to experimental data.
Soil water characteristic curves (SWCCs) and hydraulic conductivity functions (HCFs) are presented for a variety of soils that were prepared at different molding water contents and compactive efforts. The influences of dry density, molding water content, and hysteresis have been investigated. Dry density affects soil-water characteristic in terms of its air-entry value (AEV), rate of drying, and size of the hysteresis loop. The test results indicate that the SWCC and HCF obtained in terms of volumetric water content is more sensitive to the changes in dry density than molding water content. Based on cohesive soil results, some statistical relations are proposed to estimate wetting-path SWCC and HCF parameters from more easily measured drying curves. Changes in the van Genuchten's fitting parameters and residual volumetric water content are investigated for both drying and wetting conditions, with changes in the kaolin clay content.<br>Master of Science
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Khajavi, Noushafarin [Verfasser]. "Analysis of expression and function of thermo-sensitive transient receptor potential channels in cultivated human conjunctival epithelial and human uveal melanoma cells / Noushafarin Khajavi." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2015. http://d-nb.info/1075757541/34.
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Karlas, Thomas, Arne Dietrich, Veronica Peter, et al. "Evaluation of transient elastography, acoustic radiation force impulse imaging (ARFI), and enhanced liver function (ELF) score for detection of fibrosis in morbidly obese patients." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-189067.
Повний текст джерелаАнотація:
Background: Liver fibrosis induced by non-alcoholic fatty liver disease causes peri-interventional complications in morbidly obese patients. We determined the performance of transient elastography (TE), acoustic radiation force impulse (ARFI) imaging, and enhanced liver fibrosis (ELF) score for fibrosis detection in bariatric patients.
Patients and Methods: 41 patients (median BMI 47 kg/m2) underwent 14-day low-energy diets to improve conditions prior to bariatric surgery (day 0). TE (M and XL probe), ARFI, and ELF score were performed
on days -15 and -1 and compared with intraoperative liver biopsies (NAS staging).
Results: Valid TE and ARFI results at day -15 and -1 were obtained in 49%/88%and 51%/90%of cases, respectively. High skin-to-liver-capsule distances correlated with invalid TE measurements. Fibrosis of liver biopsies was staged as F1 and F3 in n = 40 and n = 1 individuals.
However, variations (median/range at d-15/-1) of TE (4.6/2.6–75 and 6.7/2.9–21.3 kPa) and ARFI (2.1/0.7–3.7 and 2.0/0.7–3.8 m/s) were high and associated with overestimation of fibrosis. The ELF score correctly classified 87.5%of patients.
Conclusion: In bariatric patients, performance of TE and ARFI was poor and did not improve after weight loss. The ELF score correctly classified the majority of cases and should be further evaluated.
30
Enous, Ridwaan. "Effect of angiotensin II, norepinephrine and the ace inhibitor, perindoprilat on the arrhythmogenic transient inward current of single isolated guinea pig and rabbit ventricular myocytes." Thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/25755.
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Latorre, Hector F. "A Multichoice Control Strategy for a VSC-HVdc." Licentiate thesis, KTH, Elektriska energisystem, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4675.
Повний текст джерелаАнотація:
Utilization of power electronics based controllable systems (or devices) in transmission systems has opened new opportunities for the power industry to optimize utilization of the existing transmission systems, and at the same time to keep high system reliability and security. As a member of these controllable systems, Voltage Source Converters-based High Voltage direct current (VSC-HVdc) systems have the ability to rapidly control the transmitted active power, and also to independently exchange reactive power with transmissions systems. Therefore, VSC-HVdcs with a suitable control scheme can offer an alternative means to enhance transient stability, to improve power oscillations damping, and to provide voltage support. An interesting application of this system is the analysis of a power system when a VSC-HVdc is connected in parallel with ac transmission lines. This thesis presents the derivation of control strategies to damp power oscillations, to enhance the transient stability and to provide voltage support for a VSC-HVdc. The thesis also formulates a multichoice control strategy and its application when the VSC-HVdc is connected in a synchronous system. The control strategy for enhancing transient stability is based on the theory of Control Lyapunov Function. The control strategy for increasing the damping is based on Linear Analysis. A very effective well known way to increase damping in the system is modulating the active power through the HVdc. However, besides the control of active power, the thesis explores an alternative way to mitigate power oscillations by controlling the reactive power. This condition might be very useful when the dc link in the VSC-HVdc system is out of service, but the converter stations are in operating conditions. A simple model of VSC-HVdc is considered in order to test the control strategy. The model represents the VSC-HVdc as an element in the power system that provides adequate interaction with other systems elements. The model is intended for analysis of power flows and electromechanical transients. It is then sufficient to consider the power frequency components of voltages and currents represented by phasors that vary with time during transients. The model is valid for symmetrical conditions, i.e. positive sequence phasors are used for the representation of the electrical state.<br>QC 20101117
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Latorre, Hector. "A Multichoice Control Strategy for a VSC-HVdc." Licentiate thesis, Stockholm : Elektriska energisystem, Electric Power Systems, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4675.
Повний текст джерела
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Chen, Wenchun [Verfasser], and Bernhard [Gutachter] Nieswandt. "Studies on the role of calcium channels and the kinase domain of transient receptor potential melastatin-like 7 (TRPM7) in platelet function / Wenchun Chen. Gutachter: Bernhard Nieswandt." Würzburg : Universität Würzburg, 2014. http://d-nb.info/1111783284/34.
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Barbosa, JoÃo Marcelo Costa. "Computational modeling of hydraulic transients in the triple function of suction cups and non slam considering the curves admission and expulsion of air." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16144.
Повний текст джерелаАнотація:
A ventosa de trÃplice funÃÃo atua na admissÃo e/ou expulsÃo de ar contido na tubulaÃÃo,
protegendo tubulaÃÃo e equipamentos contra os efeitos decorrentes do acÃmulo de ar e
golpe de arÃete. AtravÃs do orifÃcio cinÃtico, ela admite grande quantidade de ar quando
a pressÃo no interior da tubulaÃÃo torna-se inferior à atmosfÃrica, e expulsa ar apÃs a
separaÃÃo da coluna a uma pressÃo superior à atmosfÃrica. Na regiÃo de admissÃo de
ar, a ventosa com orifÃcio âNon Slamâ admite grande volume de ar atravÃs do orifÃcio
cinÃtico, e inicia a expulsÃo de ar, atravÃs do mesmo orifÃcio. A partir de um determinado
valor de pressÃo positiva, o orifÃcio cinÃtico à fechado e abre-se um orifÃcio de menor
diÃmetro, chamado de orifÃcio de "Non Slam", amortecendo, assim, o choque das colunas
lÃquidas que estavam separadas. Neste trabalho, propÃe-se uma metodologia para o cÃlculo
dos coeficientes de admissÃo e expulsÃo de ar no regime transiente a partir das curvas
disponibilizadas pelos fabricantes. O trabalho visa minimizar a falta de informaÃÃes
experimentais sobre as ventosas com base nas curvas dos fabricantes para a determinaÃÃo
dos coeficientes de admissÃo e expulsÃo de ar. Nesse estudo nÃs comparamos o efeito de
se usar um Ãnico coeficiente de descarga de ar para entrada e outro Ãnico para a saÃda de
ar versus considerar a variaÃÃo desses coeficientes de descarga à medida que as pressÃes
variam. O programa computacional UFC7, escrito em Java, implementa o transiente
hidrÃulico com suas condiÃÃes de contorno.<br>sucker triple function acts on admission and / or expulsion of air in the pipe,
protecting piping and equipment against the effects of air and accumulation
water hammer. Through kinetic hole, she admits lot of air when
the pressure inside the pipe becomes lower than atmospheric, and expels air after
separation column at a superatmospheric pressure. The inlet region
air, the suction orifice "Non slam" admits large volume of air through the orifice
Kinetic and starts expelling air through the same hole. From a certain
Positive pressure value, the kinetic orifice is closed and opens a lower orifice
diameter hole called "Non slam", cushioning, thus, the shock of columns
they were separated liquid. In this paper, we propose a methodology for calculating
the admission rates and expulsion of air in transient from the curves
provided by the manufacturers. The work aims to minimize the lack of information
Experimental suction cups on the basis of the curves for the determination of makers
the admission rates and expulsion of air. In this study we compared the effect of
using a single air discharge coefficient for input and another for output only
Air versus consider the variation of these coefficients discharge pressures as
range. The UFC7 computer program written in Java, implements the transient
Hydraulic with its boundary conditions
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Кучеренко, Ольга Костянтинівна. "Система керування процесом відділення ретурної кальцинації гідрокарбонату натрію у виробництві кальцинованої соди". Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/27106.
Повний текст джерелаАнотація:
Об’єкт розробки : система автоматизації відділення ретурної кальцинації гідрокарбонату натрію у виробництві кальцинованої сиди і зокрема система автоматизованого керування (САК) паровим кальцинатором (ПК).
Мета роботі: розробка і дослідження САК ПК, а також розробка загальної функціональної схеми виробництва соди, реалізованої на базі аналогових і дискретних засобів автоматизації.
На підставі процесів, що протікають у ПК, розроблено математичну модель ПК як об’єкт керування температурою сировини на його виході. Така модель описує ПК по каналу керування і каналу збурення.
Математичну модель ПК використаного для розробки та дослідження САК ПК.<br>Object of development: the automation system of the returne calcination of sodium bicarbonate in the production of soda ash and in particular the automated control system (ACS) by a steam calciner (SC).
The purpose of the work: the development and research of ACS SC, as well as the development of a common functional scheme of soda production, implemented on the basis of analog and discrete automation tools.
Based on the processes occurring in the SC, a mathematical model of the PC was developed as an object of control of the temperature of the raw material at its output. This model describes the SC through the control channel and the channel of perturbation.
The mathematical model of the SC used for the development and research of ACS SC.
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Chan, Teck-Wai. "Proximity-to-Separation Based Energy Function Control Strategy for Power System Stability." Queensland University of Technology, 2003. http://eprints.qut.edu.au/15840/.
Повний текст джерелаАнотація:
The issue of angle instability has been widely discussed in the power engineering literature. Many control techniques have been proposed to provide the complementary synchronizing and damping torques through generators and/or network connected power apparatus such as FACTs, braking resistors and DC links. The synchronizing torque component keeps all generators in synchronism while damping torque reduces oscillations and returns the power system to its pre-fault operating condition. One of the main factors limiting the transfer capacity of the electrical transmission network is the separation of the power system at weak links which can be understood by analogy with a large spring-mass system. However, this weak-links related problem is not dealt with in existing control designs because it is non-trivial during transient period to determine credible weak links in a large power system which may consist of hundreds of strong and weak links. The difficulty of identifying weak links has limited the performance of existing controls when it comes to the synchronization of generators and damping of oscillations. Such circumstances also restrict the operation of power systems close to its transient stability limits. These considerations have led to the primary research question in this thesis, "To what extent can the synchronization of generators and damping of oscillations be maximized to fully extend the transient stability limits of power systems and to improve the transfer capacity of the network?" With the recent advances in power electronics technology, the extension of transfer capacity is becoming more readily achievable. Complementary to the use of power electronics technology to improve transfer capacity, this research develops an improved control strategy by examining the dynamics of the modes of separation associated with the strong and weak links of the reduced transmission network. The theoretical framework of the control strategy is based on Energy Decomposition and Unstable Equilibrium Points. This thesis recognizes that under extreme loadings of the transmission network containing strong and weak links, weak-links are most likely to dictate the transient stability limits of the power system. We conclude that in order to fully extend the transient stability limits of power system while maximizing the value of control resources, it is crucial for the control strategy to aim its control effort at the energy component that is most likely to cause a separation. The improvement in the synchronization amongst generators remains the most important step in the improvement of the transfer capacity of the power system network.
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Gupta, Shuchi [Verfasser], and Bernhard [Akademischer Betreuer] Nieswandt. "The role of the Canonical transient receptor potential 6 (TRPC6) channel and the C terminal LIM domain protein of 36 kDa (CLP36) for platelet function / Shuchi Gupta. Betreuer: Bernhard Nieswandt." Würzburg : Universitätsbibliothek der Universität Würzburg, 2013. http://d-nb.info/1043906622/34.
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Xu, Kui. "The Central Nervous System Aspects of Cardiac Arrest and Resuscitation in a Rat Model of Global Ischemia." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1270689501.
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Massullo, Pam. "Aberrant subcellular targeting of the G185R neutrophil elastase mutant associated with severe congenital neutropenia induces premature apoptosis of differentiating promyelocytes & expression and function of the transient receptor potential 2 (TRPM2) i." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1172865905.
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Efthymiou, Nikolaos P. [Verfasser], Peter [Akademischer Betreuer] Rutschmann, Theodor [Akademischer Betreuer] Strobl, and Abdallah J. Hussein [Akademischer Betreuer] Malkawi. "Transient bedload transport of sediment mixtures under disequilibrium conditions : An experimental study and the development of a new dynamic hiding function / Nikolaos Efthymiou. Gutachter: Theodor Strobl ; Abdallah J. Hussein Malkawi. Betreuer: Peter Rutschmann." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1025337654/34.
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Venugopal, Karunakaran. "Femtosecond solvation, excited state dynamics, and photophysical properties of chromophores used in polynucleic acids." Doctoral thesis, [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=983550263.
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Massullo, Pam. "Aberrant subcellular targeting of the G185R neutrophil elastase mutant associated with severe congenital neutropenia induces premature apoptosis of differentiating promyelocytes & expression and function of the transient receptor potential 2 (TRPM2) ion channel in dendritic cells." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1172865905.
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43
Hiskens, Ian A. "Energy functions, transient stability and voltage behaviour /." Online version, 1990. http://bibpurl.oclc.org/web/30417.
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44
Elragig, Aiman Saleh. "On transients, Lyapunov functions and Turing instabilities." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/13789.
Повний текст джерелаАнотація:
Motivated by the papers [84, 85], this thesis considers the concepts of reactivity, Lyapunov stability and Turing patterns. We introduce the notion of P-reactivity, a new measure for transient dynamics. We extend a result by Shorten and Narendra [108] regarding joint dissipativity for second order systems. We derive an easy verifiable formula that determines systems P-reactivity with respect to a norm induced by the positive definite matrix P. An optimization problem aiming to determine the positive definite P with respect to which a stable system is most reactive is posed and solved numerically for second order systems. The stability radius is adopted as a measure of robustness of joint disspaptivity. We characterise the stability radius of joint dissipativity when the underlying systems are subject to certain specific perturbation structures. A detailed robustness analysis of the Shorten and Narendra conditions is also presented. Using the notion of common Lyapunov function we show that the necessary condition in [85] is a special case of a more powerful (i.e tighter) necessary condition. Specifically, we show that if the linearised reaction matrix and the diffusion matrix share a common Lyapunov function, then Turing instability is not possible. The existence of common Lyapunov functions is readily checked using semi-definite programming. We also further extend this to include more complicated movement mechanisms such as chemotaxis. Unlike the traditional techniques, this new necessary condition can be used to check Turing instability for systems with any dimension and any number of parameters. We apply our new conditions to various models in literature.
45
Dong, Min. "The Role of Transient Outward Current in Regulating Cardiomyocytes Electrical and Mechanical Functions." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1273521671.
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Barbosa, Carlos José Dornas Gonçalves. "Mecanismos envolvidos no aumento do risco de sangramento em pacientes com acidente vascular cerebral ou ataque isquêmico transitório prévios em uso de antiagregante plaquetário." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-09042018-082518/.
Повний текст джерелаАнотація:
Introdução: O antecedente de AVCI e/ou AIT está presente em 5% dos pacientes com coronariopatia aguda e em até 17% dos pacientes com coronariopatia crônica. Esta população apresenta elevado risco para eventos cardiovasculares, assim como para desfechos hemorrágicos maiores (principalmente quando em uso de tratamento antitrombótico). A agregabilidade plaquetária apresenta papel fundamental no balanço isquêmico/hemorrágico; entretanto, esse mecanismo é pouco estudado em pacientes com evento cérebro vascular isquêmico prévio. O principal objetivo desse estudo é avaliar se pacientes com DAC e AVCI/ AIT prévio exibem alterações na agregabilidade plaquetária que justifiquem o risco aumentado para sangramento nesses indivíduos. Casuística e Métodos: Entre janeiro de 2013 e abril de 2015, 140 pacientes foram selecionados nos bancos de dados da unidade coronária e do serviço de cirurgia cardíaca do InCor- HCFMUSP. Critérios de inclusão: coronariopatia aguda prévia (há mais de 12 meses), antecedente de AVCI/AIT (anterior ao episódio de coronariopatia aguda), uso crônico de AAS e assinatura do Termo de Consentimento Livre e Esclarecido. Critérios de exclusão: AVCH prévio, uso de antiagregação plaquetária dupla ou anti-inflamatórios não esteroidais, trombofilia ou coagulopatia conhecida, trombocitopenia ou trombocitose, angioplastia ou cirurgia cardíaca nos últimos 6 meses, disfunção renal grave ou qualquer doença terminal. Desenho do estudo: Estudo de caso e controle (1:1), com os grupos caso (AVCI/AIT prévio) e controle (sem AVCI/AIT prévio) pareados por sexo, idade, tipo de coronariopatia aguda e tempo entre a coronariopatia aguda e a inclusão no estudo. A agregabilidade plaquetária foi mensurada pelo VerifyNow Aspirin®, VerifyNow P2Y12®, Agregometria óptica com agonista ADP, Agregometria óptica com agonista adrenalina e tromboelastrografia (Reorox®). Resultados: Os grupos controle (n=70) e caso (n=70), estavam bem pareados em relação à maioria das variáveis analisadas. A idade média da população global foi de 66 anos, 73% apresentavam IAM prévio, e o tempo médio entre o episódio de coronariopatia aguda e a inclusão no presente estudo foi de 5,31 anos. No momento da avaliação os pacientes do grupo caso apresentavam valores mais elevados de pressão arterial sistólica (135,84 ± 16,09 vs 123,68 ± 16,11mmHg, p < 0,001), embora esse grupo utilizasse maior número de antihipertensivos (2,37 ± 1,09 vs 3,0 ± 1,23, p=0,006). Em relação a variáveis metabólicas, o perfil lipídico não presentou diferença significativa entre os grupos, entretanto o grupo caso apresentou maiores valores de creatinina (1,24 ± 0,35 vs 1,11 ± 0,27 mg/dL, p=0,037) e também de glicemia de jejum (116,16 ± 32,03 vs 134,88 ± 57,58 mg/dL, p=0,031). No que se refere à meta principal do estudo, a agregabilidade plaquetária foi similar nos dois grupos por todos os métodos utilizados: VerifyNow Aspirin® (525,00 ± 79,78 vs 530,35 ± 83,81 ARU nos grupos caso e controle, respectivamente, p=0,7), VerifyNow P2Y12® (262,14 ± 43,03 vs 251,74 ± 43,72 PRU, p=0,21), Agregometria óptica com agonista ADP (78,34 ± 9,02 vs 77,55 ± 9,70%, p=0,82), Agregometria óptica com agonista adrenalina (49,01± 23,93% vs 49,34 ± 21,7, p=0,77), e tromboelastografia (Firmeza máxima do coágulo: 2,136,00 ± 569,97 vs 2.001,27 ± 635,68 Pa, p=0,19). Conclusão: Em pacientes com doença arterial coronária crônica a agregabilidade plaquetária foi similar nos indivíduos com ou sem AVCI/AIT. Esses resultados apontam para que outros mecanismos sejam responsáveis pelo elevado risco hemorrágico dessa população<br>Background: Ischemic stroke (IS) or transient ischemic attack (TIA) history is present in 5% of patients with acute coronary syndrome (ACS) and in 17% of patients with stable atherosclerotic disease (CAD). This population has a higher risk for major cardiovascular events and an increased incidence of major hemorrhagic outcomes when subjected to modern antithrombotic regimens, Platelet aggregability have key role in \"ischemic-hemorrhagic\" balance, however, these factors are little known in the population with prior cerebrovascular event. The aim of this study is to evaluate whether patients with coronary artery disease and previous IS/ TIA exhibit alterations in platelet aggregation, justifying the increased bleeding risk of these individuals. Methods: Between January 2013 and April 2015, 140 participants were selected in the coronary care unit and cardiac surgery service databank. Inclusion criteria: prior ACS (over 12 months), history of IS/ TIA previous to ACS, chronic use of aspirin since ACS and agreement to the consent form. Exclusion criteria: prior hemorrhagic stroke, current dual antiplatelet therapy or anti-inflammatory non-steroidal, any thrombophilia or coagulopathy, thrombocytopenia, thrombocytosis, PCI or CABG in the last 6 months, severe renal impairment and any terminal illness. Study design: Case-control study (1:1), case group (previous IS/TIA) and control group (without previous IS/TIA) matched for sex, age, type of previous ACS, time between ACS and inclusion in the study. Platelet aggregation was assessed by VerifyNow Aspirin®, VerifyNow P2Y12®, Light transmission aggregometry aggonist with agonists adrenaline, Light transmission aggregometry aggonist with ADP, and thromboelastography (Reorox®). Results: The control group (n=70) and case group (n=70), were well matched. The mean age was 63 years, about 73% presented previous AMI and the index ACS occurred 5,31 years before study inclusion. At the evaluation day patients in the case group presented higher SBP levels (135.84 ± 16.09 vs 123.68 ± 16.11 mmHg, p < 0,001), although this group were using more antihypertensive medications (2.37 ± 1.09 vs 3.0 ± 1.23, p=0,006). In relation to metabolic profile, lipid profile did not presented diferences, however, case group presented higher values for creatinine (1.24 ± 0.35 vs 1.11 ± 0.27 mg/dL, p=0.037) and also presented higher values for fasting glucose.(116.16 ± 32.03 vs 134.88 ± 57.58 mg/dL, p=0.031) Platelet aggregation was statistically similar in both groups: VerifyNow Aspirin® (525.00 ± 79.78 vs 530.35 ± 83.81 ARU, p=0.7), VerifyNow P2Y12® (262.14 ± 43.03 vs 251.74 ± 43.72 PRU, p=0.21), Light transmission aggregometry aggonist with agonists ADP (78,34 ± 9,02 vs 77,55 ± 9,70%, p=0,82), Light transmission aggregometry aggonist with adrenaline (49,01 ± 23,93% vs 49,34 ± 21,7, p=0,77) and thromboelastography (maximum clot firmness: 2.136,00 ± 569,97 vs 2.001,27 ± 635,68 Pa, p=0,19). Conclusion: Platlet aggregability is similar in CAD patients with or without previous IS/TIA and this results point at other reasons to justify the high risk for bleeding in this patients
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Cook, Amanda Laurie. "Diet and bowel function in adults." Thesis, London South Bank University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313002.
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Zhong, Bing. "Lossy Transmission Line Modeling and Simulation Using Special Functions." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195307.
Повний текст джерелаАнотація:
A new algorithm for modeling and simulation of lossy interconnect structures modeled by transmission lines with Frequency Independent Line Parameters (FILP) or Frequency Dependent Line Parameters (FDLP) is developed in this research. Since frequency-dependent RLGC parameters must be employed to correctly model skin effects and dielectric losses for high-performance interconnects, we first study the behaviors of various lossy interconnects that are characterized by FILP and FDLP. Current general macromodeling methods and Model Order Reduction (MOR) algorithms are discussed. Next, some canonical integrals that are associated with transient responses of lossy transmission lines with FILP are presented. By using contour integration techniques, these integrals can be represented as closed-form expressions involving special functions, i.e., Incomplete Lipshitz-Hankel Integrals (ILHIs) and Complementary Incomplete Lipshitz-Hankel Integrals (CILHIs). Various input signals, such as ramp signals and the exponentially decaying sine signals, are used to test the expressions involving ILHIs and CILHIs. Excellent agreements are observed between the closed-form expressions involving ILHIs and CILHIs and simulation results from commercial simulation tools. We then developed a frequency-domain Dispersive Hybrid Phase-Pole Macromodel (DHPPM) for lossy transmission lines with FDLP, which consists of a constant RLGC propagation function multiplied by a residue series. The basic idea is to first extract the dominant physical phenomenology by using a propagation function in the frequency domain that is modeled by FILP. A rational function approximation is then used to account for the remaining effects of FDLP lines. By using a partial fraction expansion and analytically evaluating the required inverse Fourier transform integrals, the time-domain DHPPM can be decomposed as a sum of canonical transient responses for lines with FILP for various excitations (e.g., trapezoidal and unit-step). These canonical transient responses are then expressed analytically as closed-form expressions involving ILHIs, CILHIs, and Bessel functions. The DHPPM simulator can simulate transient results for various input waveforms on both single and coupled interconnect structures. Comparisons between the DHPPM results and the results produced by commercial simulation tools like HSPICE and a numerical Inverse Fast Fourier Transform (IFFT) show that the DHPPM results are very accurate.
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Manney, Sanjay (Sanjay Leela) Carleton University Dissertation Engineering Electrical. "Transient analysis of nonuniform high-speed interconnects." Ottawa, 1992.
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Najafiyazdi, Mostafa. "Anisotropic mesh adaptation for transient problems and functional-output variables." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104799.
Повний текст джерелаАнотація:
Mesh adaptation is modification of an existing mesh as to accurately capture physical phenomena without increasing computational cost excessively. Among many challenges remained in this field, "unsteady mesh adaptation" and "functional-output mesh adaptation" are the two topics addressed in this work. "Transient-Fixed-point" method is a new approach for unsteady mesh adaptation as an implicit coupling between the mesh and the solution. What differentiates transient-fixed-point from steady adaptation methods is the metric intersection through time. In this work a new scheme for transient metric intersection is proposed for orthogonal data preserving. Another challenge in mesh adaptation is to control mesh modifications according to an integral function, known as functional-output, (e.g. lift, drag, moments, etc.) rather than the directly computed variables (e.g. velocity, pressure, Mach, etc.). Such control comes from a suitable edge-based error evaluation to be defined according to the chosen functional. One such definition is proposed in this work that drives surface mesh adaptation based on the chosen functional-output function.<br>L'adaptation de maillage est la modification d'un maillage existant afin de saisir avec précision les phénomènes physiques sans augmentation excessive du coût de calcul. Parmi les nombreux défis qui demeurent dans ce domaine, l'adaptation de maillage de manière instable et l'adaptation de maillage selon un « functional-output » sont les deux thèmes abordés dans ce travail. La méthode « Transient-Fixed-point » est une nouvelle approche pour l'adaptation de maillage de manière instable. Cette méthode consiste à formée un lien entre le maillage et la solution. Ce qui différencie la méthode « Transient-Fixed-point » de méthodes d'adaptation constante est l'intersection des métriques à travers le temps. Dans cet ouvrage, un nouveau régime pour l'intersection de métriques transitoire est proposé afin de préserver l'orthogonalité des données.Un autre défi de l'adaptation de maillage est de contrôler les modifications apporté à la maille selon une fonction intégrale, connu sous le nom de « functional-output » (par exemple, la portance, la trainée, des moments, etc.) plutôt que de calculées directement les variables (par exemple vitesse, pression, Mach, etc.). Un tel contrôle provient d'une d'évaluation approprié de l'erreur des lisières à être définies en fonction des choix de « functional ». Une telle définition est proposée dans ce travail qui entraine l'adaptation de maillage de surface en fonction du« functional-output » choisi.