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A Mathematical Model for the Effect of Enzymes on Metabolism of Pharmacologically Active Substances

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Applied Mathematics 2021年第1期12卷 1-17页

作者： donald A. drew Department of Mathematical Sciences Rensselaer Polytechnic Institute Troy NY USA

Addiction is a societal issue with many negative effects. Substances that cause addictive reactions are easily ingested and interact with some part of the neural pathway. This paper describes a mathematical model for the systemic level of a substance subject to degradation (via metabolism) and reversible binding to psychoactive sites. The model allows the determination of bound substance levels during the processing of a dose, and how the maximum level depends on system parameters. The model also allows the study of a particular periodic repetitive dosing described by a rapid ingestion if a dose is at constant intervals.

关键词： Mathematical Model Addiction Metabolism

A Mathematical Model for Nutrient Metabolic Chemistry

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Applied Mathematics 2018年第6期9卷 647-671页

作者： donald A. drew Department of Mathematical Sciences Rensselaer Polytechnic Institute Troy USA

A model based on chemical kinetics for the rate of utilization and/or storage of carbohydrates, fats and proteins is derived and analyzed. This system is studied under different conditions of supply and usage and for short term dynamics and long term dynamics. Both the short term and long term models indicate that starting above an equilibrium threshold leads to growth of the stored species. Results from the short-term and long-term submodels show that the qualitative behavior depends on the levels of certain enzymes. The analysis of a model for enzyme dynamics indicates that the steady-state level of an enzyme should depend on the rate of supply of the substrate.

关键词： Nutrient Metabolic Chemistry

The Interface Between Pragmatics and Conversation Analysis

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外国语 2018年第1期41卷 2-22页

作者： Paul drew Loughborough University UK

In his authoritative and brilliant account of Pragmatics,Levinson(1983)included Conversation Analysis(CA)firmly as part of *** have perhaps been more cautious,even sceptical,about whether CA is really relevant to the Pragmatics programme;and it has to be said that some conversation analysts have been rather stand-offish about being associated with Pragmatics,regarding CA’s programme as very different from that of *** there are many differences and divergences between CA and Pragmatics,my own view is that CA shares with Pragmatics a number of focal interests that lie at or close to the heart of *** I will explore some connections between them,focusing on the contributions CA makes to our understanding of the pragmatics of language use,especially in three of the foundational areas of Pragmatics—namely Implicature(*** Grice 1975),Speech Acts(social action)(*** Austin 1962 and Searle 1969)and Presupposition and Well-Formedness(*** Lakoff1971).I will show examples that demonstrate the distinctiveness of CA’s approach to these core pragmatic aspects of language use—in the spirit of demonstrating how CA’s approach complements and does not detract from approaches in Pragmatics.

关键词： conversation analysis sequential approach empirical complement pragmatics

Determination of Statistical Properties of Microtubule Populations

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Applied Mathematics 2016年第13期7卷 1456-1475页

作者： Tyson DiLorenzo Lee Ligon donald drew Department of Mathematics Rensselaer Polytechnic Institute Troy USA Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies Rensselaer Polytechnic Institute Troy USA

Microtubules are structures within the cell that form a transportation network along which motor proteins tow cargo to destinations. To establish and maintain a structure capable of serving the cell’s tasks, microtubules undergo deconstruction and reconstruction regularly. This change in structure is critical to tasks like wound repair and cell motility. Images of fluorescing microtubule networks are captured in grayscale at different wavelengths, displaying different tagged proteins. The analysis of these polymeric structures involves identifying the presence of the protein and the direction of the structure in which it resides. This study considers the problem of finding statistical properties of sections of microtubules. We consider the research done on directional filters and utilize a basic solution to find the center of a ridge. The method processes the captured image by centering a circle around pre-determined pixel locations so that the highest possible average pixel intensity is found within the circle, thus marking the center of the microtubule. The location of these centers allows us to estimate angular direction and curvature of the microtubules, statistically estimate the direction of microtubules in a region of the cell, and compare properties of different types of microtubule networks in the same region. To verify accuracy, we study the results of the method on a test image.

关键词： Microtubule Image Analysis Curvature

Conversation Analysis and Social Action

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外国语 2013年第3期36卷 2-19页

作者： Paul drew Loughborough University UK

Conversation analysis(CA) has come to be regarded as focusing primarily on turn-taking,on the way speakers design,hold and extend their turns at talk;how they select next speakers;how others know when it is their turn to speak;how orderly transition from one turn to the next is managed and how turns *** argument in this paper is that this research focus is waning,and that in its place a new direction is emerging(or perhaps reemerging) -the investigation of how social actions are conducted through *** research direction connects with an area that is quite familiar in linguistic pragmatics,that of speech act analysis(Austin,Searle).But CA's approach is quite distinctive,exploring as it does the systematic basis for the selection of one from among the alternative constructions or formats for doing certain *** is illustrated through recent studies of offering and requesting,with some further observations of negatively formatted interrogatives used to make *** studies show that speakers select between the alternative available forms on the basis of the sequential position in which the speaker is conducting that action.

关键词：英语学习学习方法阅读知识阅读材料

Particle Size Optimization of Thermochemical Salt Hydrates for High Energy Density Thermal Storage

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Energy & Environmental Materials 2024年第2期7卷 326-333页

作者： a.drew Martin drew Lilley Raνi Prasher Sumanjeet Kaur Energy Technologies Area Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Mechanical Engineering UC BerkeleyBerkeleyCA 94720USA

Thermal energy storage(TES)solutions offer opportunities to reduce energy consumption,greenhouse gas emissions,and ***,they can help reduce the peak load and address the intermittency of renewable energy sources by time shifting the load,which are critical toward zero energy *** materials(TCMs)as a class of TES undergo a solid-gas reversible chemical reaction with water vapor to store and release energy with high storage capacities(600 kWh m^(-3))and negligible self-discharge that makes them uniquely suited as compact,stand-alone units for daily or seasonal ***,TCMs suffer from instabilities at the material(salt particles)and reactor level(packed beds of salt),resulting in poor multi-cycle efficiency and high-levelized cost of *** this study,a model is developed to predict the pulverization limit or Rcrit of various salt hydrates during thermal *** is critical as it provides design rules to make mechanically stable TCM composites as well as enables the use of more energy-efficient manufacturing process(solid-state mixing)to make the *** model is experimentally validated on multiple TCM salt hydrates with different water content,and effect of Rcrit on hydration and dehydration kinetics is also investigated.

关键词： high energy density hydration kinetics long-term cycling thermal energy storage thermochemical materials

Janice drew's work on diet and cancer

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World Journal of Gastrointestinal Pathophysiology 2011年第4期2卷 61-64页

作者： Janice drew Rowett Institute of Nutrition and Health University of AberdeenGreenburn RoadBucksburnAberdeenAB21 9SBUnited Kingdom

Obesity and associated reduced consumption of plant derived foods are linked to increased risk of colon cancer as well as a number of other organ specific *** processes are a contributing factor but the precise mechanisms remain *** and cancer incidence are increasing worldwide,presenting bleak prospects for reducing,or preventing,obesity related *** incidence of these preventable cancers can be achieved with greater understanding of the molecular mechanisms linking diet and *** drew has developed a research program over recent years to investigate molecular mechanisms related to consumption of anti-inflammatory metabolites generated from consumption of plant based diets,the impact of high fat diets and associated altered metabolism and obesity on regulation of colon inflammatory responses and processes regulating the colon *** strategies have been developed incorporating transcriptomics,including the novel gene expression technology,the GenomeLab System and proteomics,together with biochemical analyses of plasma and tissue samples to assess correlated changes in oxidative stress,inflammation and *** approaches developed have achieved success in establishing antioxidant and anti-inflammatory activity of dietary antioxidants and associated genes and pathways that interact to modulate redox status in the *** processes and genes altered in response to obesity and high fat diets have provided evidence of molecular mechanisms that are implicated in obesity related cancer.

关键词： Diet and cancer Obesity-related cancer Adipokines Leptin Phenolic acids Mitochondria Proteomics Multiplex gene expression

A multigroup model for cholera dynamics and control

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International Journal of Biomathematics 2016年第1期9卷 1-27页

作者： drew Posny Chairat Modnak Jin Wang Department of Mathematics Winyate University Wingate NC 28174 USA Department of Mathematics Naresuan University Phitsanulok 65000 Thailand Department of MathematicsUniversity of Tennessee a$ Chattanooga Chattanooga TN 37403 USA

We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that the basic reproduction number R0 remains a sharp threshold for cholera dynamics in multigroup settings. We verify the analysis by numerical simulation results. We also perform an optimal control study to explore optimal vaccination strategy for cholera outbreaks.

关键词： Cholera epidemics multigroup models optimal control.

Who＇s your neighbor？ Acoustic cues to individual identity in red squirrel Tamiasciurus hudsonicus rattle calls

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Current Zoology 2012年第5期58卷 758-764页

作者： Shannon M. DIGWEED drew RENDALL Teana IMBEAU Departments of Psychology and Biological Science Grant MacEwan University Edmonton Alberta T5J 2P2 Canada Department of Psychology University of Lethbridge Lethbridge Alberta T1K 3M4 Canada Department of Biological Science Grant MacEwan University Edmonton Alberta T5J 2P2 Canada

North American red squirrels Tamiasciurus hudsonicus often produce a loud territorial rattle call when conspecifics enter or invade a territory. Previous playback experiments suggest that the territorial rattle call may indicate an invader＇s identity as squirrels responded more intensely to calls played from strangers than to calls played from neighbors. This dear-enemy effect is well known in a variety of bird and mammal species and functions to reduce aggressive interactions between known neighbors. However, although previous experiments on red squirrels suggest some form of individual differentiation and thus recognition, detailed acoustic analysis of potential acoustic cues in rattle calls have not been conducted. If calls function to aid in conspecific identifi- cation in order to mitigate aggressive territorial interactions, we would expect that individual recognition cues would be acoustically represented. Our work provides a detailed analysis of acoustic cues to identity within rattle calls. A total of 225 calls across 32 in- dividual squirrels from Sheep River Provincial Park, Kananaskis, AB, Canada, were analyzed with discriminant function analysis for potential acoustic cues to individual identity. Initial analysis of all individuals revealed a reliable acoustic differentiation across individuals. A more detailed analysis of clusters of neighboring squirrels was performed and results again indicated a statistically significant likelihood that calls were assigned correctly to specific squirrels （55%-75% correctly assigned）; in other words squirrels have distinct voices that should allow for individual identification and discrimination by conspecifics [Current Zoology 58 （5）： 758-764, 2012].

关键词： Vocal communication Territory calls Red squirrel Dear-enemy Individual identity