Spelling suggestions: "subject:"2potential"" "subject:"60potential""
521 |
Hepatocyte Water Volume and Potassium Activity During Hypotonic StressWang, Kening, Wondergem, Robert 01 August 1993 (has links)
Hepatocytes exhibit a regulatory volume decrease (RVD) during hypotonic shock, which comprises loss of intracellular K+ and Cl- accompanied by hyperpolarization of transmembrane potential (Vm) due to an increase in membrane K+ conductance, (GK). To examine hepatocyte K+ homeostasis during RVD, double-barrel, K+-selective microelectrodes were used to measure changes in steady-state intracellular K+ activity (aKi) and Vm during hyposmotic stress. Cell water volume change was evaluated by measuring changes in intracellular tetramethylammonium (TMA+). Liver slices were superfused with modified Krebs physiological salt solution. Hyposmolality (0.8×300 mosm) was created by a 50 m m step-decrease of external sucrose concentration. Hepatocyte Vm hyperpolarized by 19 mV from -27 ± 1 to -46 ± 1 mV and aKidecreased by 14% from 91 ± 4 to 78 ± 4 m m when slices were exposed to hyposmotic stress for 4-5 min. Both Vm and aKireturned to control level after restoring isosmotic solution. In paired measurements, hypotonic stress induced similar changes in Vm and aKiboth control and added ouabain (1 m m) conditions, and these values returned to their control level after the osmotic stress. In another paired measurement, hypotonic shock first induced an 18-mV increase in Vm and a 15% decrease in aKiin control condition. After loading hepatocytes with TMA+, the same hypotonic shock induced a 14-mV increase in Vm and a 14% decrease in aTMAi. This accounted for a 17% increase of intracellular water volume, which was identical to the cell water volume change obtained when aKiwas used as the marker. Nonetheless, hyposmotic stress-induced changes in Vm and aKiwere blocked partly by Ba2+ (2 m m). We conclude that (i) hepatocyte Vm increases and aKidecreases during hypotonic shock; (ii) the changes in hepatocyte Vm and aKiduring and after hypotonic shock are independent of the Na+-K+ pump; (iii) the decrease in aKiduring hypotonic stress results principally from hepatocyte swelling.
|
522 |
Development of a Fully Vectorized Potential Flow SolverYu, Wenyuan January 2017 (has links)
Centered finite difference is the basic method in this paper for spatial discretization. In general, except the schemes that will be used adjacent tothe boundary points, centered finite difference schemes will be used on the main mesh points. Depending on the requirement of order of accuracy and optimization, different multi-point stencil schemes will be built in Matlab in the form of matrix. As a result, solving PDEs is actually operating matrices in Matlab. Standard schemes and optimized schemeswill be tested with 1D linear convection equation before applying them to the solvers. In 2D-pulse case, the rectangular domain will be transformed into a wavy domain and as a result Jacobian transformation method will betested. Results from different schemes will be compared with the analytical solution in two dimensional pulse case.
|
523 |
Identification and quantification ofmicrobiological risks in board production : A study of ATP bioluminescence and redox potential / Identifiering och kvantifiering av risker kopplade till mikrobiologi vid kartongproduktion : En studie om ATP bioluminescens och redox potentialBartos, Claudia January 2022 (has links)
Stora Enso is a well-established provider of renewable solution packaging and board materials.Board products for liquid packaging and folding cartons for food are particularly sensitive tothe microbiological contaminants. In the manufacturing process, microbiological growth occursdue to environmental favourable conditions. Most of the microorganisms eventually die in theboard machine. The microflora in the process consists mainly of bacteria from genera Bacillusand Paenibacillus, and these species have a unique characteristic of forming endospores. Thespores are non-vegetative capsules transformed from the dying bacteria, with its purpose ofprotecting the bacterial genome from the unfriendly environment as it passes through in theboard machine. The levels of spores found in the board products are usually low, but suddenpeaks of spores in the board products are unwanted for food and health safety. Bacterial andspore cultivation is a standard method to investigate microbiological activity. The method isinaccessible due to 48-hour incubation time for obtaining test results and does not provide anyoverview in a short time frame of where in the process that might triggered sporulation. In thelong run, it can cause production losses that affect the prospects of the board production.The purpose of this study is to investigate a new analysis method to facilitate identification andquantification of microbiological activity with ATP bioluminescence (AdenosineTriphosphate) measurement and redox potential, and as well investigate the main process sitethat possibly causes the issue. ATP bioluminescence measures the concentration of ATP inrelation to the number of bacterial cells. The study was limited to the broke system due to theclosed system and accumulation of microorganisms. The broke system manages the reuse ofdowngraded new paper board. For the laboratory work, 15 process positions were selected inthe broke system. Pulp were sampled from each process position for each laboratory workday,and measurements of ATP bioluminescence, redox potential, pH, temperature, TOC (totalorganic carbon), retention time, and bacterial and spore cultivation were completed as well. Thecollected data were studied in a multivariate analysis and correlograms were produced for eachprocess position. In addition, a parallel study of a lab scale broke tower simulation wasperformed to further investigate if the broke tower could be the source of the microbiologicalactivity.The obtained results showed low correlations between the process parameters and the totalbacterial and spore concentration. Similar results were obtained for ATP bioluminescence andredox potential, resulted in a low correlation to the total bacterial and spore concentration aswell. The simulation gave additional insight in the function of ATP bioluminescence and redoxpotential.The conclusion is that ATP bioluminescence is an accessible method due to high repeatability,however the reliability is lacking. The analysis is not reliable because of low correlationbetween the total bacterial and spore concentration. Redox potential is both a reliable andaccessible method to identify and quantify the microbiological growth in the system, becauseit signifies the environmental conditions for the bacterial growth. It has been proven in the brokesimulation. Further research is needed to understand the representation in relation to thebacterial growth behind each analysis in order to fully consider the analysing measurementapplicable. Due to low correlations between the variables in each process position, anyassumptions cannot be considered in any specific process position that might be main cause ofraised spore values in board products. / Stora Enso är en väletablerad leverantör av förnybara lösningar för förpackningar ochkartongmaterial. Kartongprodukter för vätskeförpackningar och vikkartong för livsmedel ärsärskilt känslig för mikrobiologisk aktivitet. I tillverkningsprocessen sker mikrobiologisktillväxt på grund av gynnsamma miljöförhållanden. De flesta av de vegetativa cellerna dör såsmåningom i kartongmaskinen, men en stor del av mikrofloran består av bakterier från släktenaBacillus och Paenibacillus. Dessa arter har en unik egenskap att bilda endosporer. Sporerna äricke-vegetativa kapslar som transformerats från de döende bakterierna, med syftet att skyddabakteriegenomet från den ogynnsamma miljön som passeras i genom maskinen. Nivåerna avsporer som finns i kartongprodukterna är låga, men plötsliga förhöjda värden av sporer ikartongprodukterna är oönskade för livsmedels- och hälsosäkerheten. Bakterie- och sporodlingär en standardmetod att undersöka den mikrobiologiska aktiviteten. Metoden är otillgängligvars resultat visas efter 48 timmar inkubation. Metoden ger ingen översikt var i processen somkan ha framkallats sporulering, och detta bildar en diffus överblick var i processen inom korttidsram som kan ha bidragit till sporuleringen. På lång sikt kan det orsakas produktionsförlustersom påverkar kartongproduktionens framtidsutsikter.Syftet med denna studie är att undersöka nya analysmetoder för att underlätta identifiering ochkvantifiering av mikrobiologisk aktivitet med en ATP bioluminescens (Adenosin Trifosfat)mätning och redoxpotential och även undersöka den huvudsakliga processposition som orsakardet huvudsakliga problemet. ATP bioluminescens mäter koncentrationen av ATP i förhållandetill antalet vegetativa celler. Studien begränsades till utskottssystemet på grund av slutet systemoch ansamling av mikroorganismer. För laborationsarbetet valdes 15 processpunkter ut iutskottssystemet. Utskottsmassan togs från varje processpunkt för varje laborationsdag, ochmätningar av ATP bioluminescens, redoxpotential, pH, temperatur, TOC (totalt organiskt kol),retentionstid och bakterie- och sporodling genomfördes också. De insamlade data studerades ien multivariat analys och korrelogram togs fram för varje processpunkt. En parallellundersökning genomfördes med en labbsaklig simulering av utskottstornet för att ytterligareundersöka om tornet är möjligtvis källan till den mikrobiologiska aktiviteten.De erhållna resultaten visade låg korrelation mellan processparametrarna och den totalabakterie- och sporkoncentrationerna i samtliga processpositioner. ATP bioluminescens ochredox potential erhöll låg korrelation mellan den totala bakterie- och sporkoncentrationen, mensimuleringen gav tydligare förståelse i de båda mätningarnas funktion.Slutsatsen är att ATP är en tillgänglig metod eftersom det är repeterbar. Däremot har det visatsatt den är opålitlig, på grund av den låga korrelationen mellan den totala bakteriella ochsporhalten. Redox potential är pålitlig att använda, vilket har visats i simuleringen. Denförklarar de miljömässiga förhållandena i systemet och på så sätt stärks förståelsen om denbakteriella tillväxten. Vidare forskning behövs för att förstå betydelsen i samband med denbakteriella tillväxten bakom varje mätning för att analysmetoden ska vara applicerbar. På grundav låga korrelationer mellan variablerna i varje processposition kan några antaganden intebeaktas i någon specifik processposition som kan vara huvudorsaken till förhöjda sporvärden ikartongprodukter.
|
524 |
Action potentials as indicators of metabolic perturbations for temporal proteomic analysisKolli, Aditya Reddy 01 January 2014 (has links)
The single largest cause of compound attrition during drug development is due to inadequate tools capable of predicting and identifying protein interactions. Several tools have been developed to explore how a compound interferes with specific pathways. However, these tools lack the potential to chronically monitor the time dependent temporal changes in complex biochemical networks, thus limiting our ability to identify possible secondary signaling pathways that could lead to potential toxicity. To overcome this, we have developed an in silico neuronal-metabolic model by coupling the membrane electrical activity to intracellular biochemical pathways that would enable us to perform non-invasive temporal proteomics. This model is capable of predicting and correlating the changes in cellular signaling, metabolic networks and action potential responses to metabolic perturbation. The neuronal-metabolic model was experimentally validated by performing biochemical and electrophysiological measurements on NG108-15 cells followed by testing its prediction capabilities for pathway analysis. The model accurately predicted the changes in neuronal action potentials and the changes in intracellular biochemical pathways when exposed to metabolic perturbations. NG108-15 cells showed a large effect upon exposure to 2DG compared to cyanide and malonate as these cells have elevated glycolysis. A combinational treatment of 2DG, cyanide and malonate had a much higher and faster effect on the cells. A time-dependent change in neuronal action potentials occurred based on the inhibited pathway. We conclude that the experimentally validated in silico model accurately predicts the changes in neuronal action potential shapes and proteins activities to perturbations, and would be a powerful tool for performing proteomics facilitating drug discovery by using action potential peak shape analysis to determine pathway perturbation from an administered compound.
|
525 |
Development of a Meshless Method to Solve Compressible Potential FlowsRamos, Alejandro 01 June 2010 (has links) (PDF)
The utility of computational fluid dynamics (CFD) for solving problems of engineering interest has experienced rapid growth due to the improvements in both memory capacity and processing speed of computers. While the capability now exists for the solution of the Navier-Stokes equations about complex and complete aircraft configurations, the bottleneck within the process is the time consuming task of properly generating a mesh that can accurately solve the governing partial differential equations (PDEs). This thesis explored two numerical techniques that attempt to circumvent the difficulty associated with the meshing process by solving a simplified form of the continuity equation within a meshless framework. The continuity equation reduces to the full potential equation by assuming irrotational flow. It is a nonlinear PDE that can describe flows for a wide spectrum of Mach numbers that do not exhibit discontinuities. It may not be an adequate model for the detailed analysis of a complex flowfield since viscous effects are not captured by this equation, but it is an appealing alternative for the aircraft designer because it can provide a quick and simple to implement estimate of the aerodynamic characteristics during the conceptual design phase.
The two meshless methods explored in this thesis are the Dual Reciprocity Method (DRM) and the Generalized Finite Difference Method (GFD). The Dual Reciprocity Method was shown to have the capability to solve for the two-dimensional subcritical compressible flow over a Circular Cylinder and the non-lifting flow for a NACA 0012 airfoil. Unfortunately these solutions were obtained with the requirement of a priori knowledge of the solution to tune a parameter necessary for proper convergence of the algorithm. Due to the shortcomings of applying the Dual Reciprocity Method, the Generalized Finite Difference Method was also investigated. The GFD method solves a PDE in differential form and can be thought of as a meshless form of a standard finite difference scheme. This method proved to be an accurate and general technique for solving the previously mentioned cases along with the lifting flow about a NACA 0012 airfoil. It was also demonstrated that the GFD method could be formulated to discretize the full potential equation with second order accuracy. Both solution methods offer their own set of unique advantages and challenges, but it was determined that the GFD Method possessed the flexibility necessary for a meshless technique to become a viable aerodynamic design tool.
|
526 |
Development of a Small and Inexpensive Terrain Avoidance System for an Unmanned Aerial Vehicle via Potential Function Guidance AlgorithmWallace, Shane Alan 01 September 2010 (has links) (PDF)
Despite the first unmanned aerial vehicle (UAV) mission being flown on Aug 22 1849 to bomb Venice UAVs have only recently began to modernize into sophisticated tools beyond simple aerial vehicles. With an increasing number of potential applications, such as cargo delivery, communications, search and rescue, law enforcement, and homeland security, the need for appropriate UAV technology advancement also arose. Here, the development of a low-cost collision avoidance system is described. Hardware was tested and selected based on predetermined constraints and goals. Additionally, a variety of potential functions were explored and assessed at their effectiveness in preventing a collision of a UAV with mountainous terrain. Simulations were conducted using Cloud Cap’s Piccolo autopilot in conjunction with Matlab. Based on these simulations, a set of potential functions was selected to be used with the chosen hardware on subsequent UAV-development-related projects.
|
527 |
Adoption of AI-powered Industrial Robots in Auto Component Manufacturing CompaniesPillai, R., Sivathanu, B., Mariani, M., Rana, Nripendra P., Yang, B., Dwivedi, Y.K. 08 October 2020 (has links)
Yes / The usage of AI-empowered Industrial Robots (InRos) is booming in the Auto Component Manufacturing Companies (ACMCs) across the globe. Based on a model leveraging the Technology, Organisation, and Environment (TOE) framework, this work examines the adoption of InRos in ACMCs in the context of an emerging economy. This research scrutinizes the adoption intention and potential use of InRos in ACMCs through a survey of 460 senior managers and owners of ACMCs in India. The findings indicate that perceived compatibility, external pressure, perceived benefits and support from vendors are critical predictors of InRos adoption intention. Interestingly, the study also reveals that IT infrastructure and government support do not influence InRos adoption intention. Furthermore, the analysis suggests that perceived cost issues negatively moderate the relationship between the adoption intention and potential use of InRos in ACMCs. This study offers a theoretical contribution as it deploys the traditional TOE framework and discovers counter-intuitively that IT resources are not a major driver of technology adoption: as such, it suggests that a more comprehensive framework than the traditional RBV should be adopted. The work provides managerial recommendations for managers, shedding light on the antecedents of adoption intention and potential use of InRos at ACMCs in a country where the adoption of InRos is in a nascent stage.
|
528 |
Commitment and Discourse Particles in Japanese / コミットメントと日本語の談話助詞Matsumoto, Daiki 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(人間・環境学) / 甲第24685号 / 人博第1058号 / 新制||人||248(附属図書館) / 2022||人博||1058(吉田南総合図書館) / 京都大学大学院人間・環境学研究科共生人間学専攻 / (主査)教授 藤田 耕司, 教授 谷口 一美, 准教授 守田 貴弘, 教授 田中 伸一 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM
|
529 |
G-Aminobutyric Acid-Producing Bacteria: Screening, Probiotic Potential, and Impact on Gut Microbiota Under a Simulated Human ColonMousavi, Rojaalsadat 08 November 2021 (has links)
This study aimed to isolate and characterize in-vitro and under simulated colonic conditions, probiotic candidates isolated from food environment producing γ-aminobutyric acid (GABA), a major inhibitory neuromediator of the enteric nervous system with a potential role in modulating the immune system in many health disorders. Several lactic acid bacteria were isolated and detected for the presence of the gadB gene using PCR and GAD enzymatic assay. The most active strains with high and fast production kinetics were identified, characterized, and included Streptococcus thermophilus, Lactiplantibacillus plantarum, and Lactobacillus delbrueckii subsp. bulgaricus. The biological safety (i.e., sensitivity to antibiotics and the presence of virulence factors) and probiotic potential (i.e., resistance to gastrointestinal conditions and whole-genome sequencing) of identified bioactive strains was also confirmed in vitro. The growth, GABA production, and competitiveness of selected probiotic candidates (B. animalis, S. thermophilus, and L. bulgaricus) were investigated in the presence of human gut microbiota ex vivo in a model of a proximal colon mimicking physiological and microbiological conditions of the human large intestine. Supplementation with GABA-producing probiotic candidates did not affect the overall gut microbiota diversity over 48 h of treatment. However, we observed modulation of the microbiome composition, especially change of Bacteroides population, a key gut microbe associated with anti-depressive and anti-inflammatory activities. The level of microbiota-generated butyrate within 12 h of treatment was significantly increased compared to control. Results from this study demonstrated the probiotic potential of tested GABA-producing bacteria and their impact on gut microbiota structure and metabolism, suggesting their suitability for gut health-promoting application.
|
530 |
Association Between Maternal Dietary Inflammation Potential and Exclusive BreastfeedingCetinkaya, Hatice January 2022 (has links)
No description available.
|
Page generated in 0.1952 seconds