检索结果-南通市图书馆

Solutions:how adaptive changes in cellular fluids enable marine life to cope with abiotic stressors

在线全文

学校读者我要写书评

暂无评论

Marine Life Science & Technology 2022年第3期4卷 389-413页

作者： george N.Somero Department of Biology Hopkins Marine StationStanford UniversityPacific GroveCA 93950USA

The seas confront organisms with a suite of abiotic stressors that pose challenges for physiological *** in temperature,hydrostatic pressure,and salinity have potential to disrupt structures,and functions of all molecular systems on which life *** evolution,sequences of nucleic acids and proteins are adaptively modified to“fit”these macromolecules for function under the particular abiotic conditions of the *** these macromolecular adaptations are alterations in compositions of solutions that bathe macromolecules and affect stabilities of their higher order structures.A primary result of these“micromolecular”adaptations is preservation of optimal balances between conformational rigidity and flexibility of *** adaptations involve several families of organic osmolytes,with varying effects on macromolecular stability.A given type of osmolyte generally has similar effects on DNA,RNA,proteins and membranes;thus,adaptive regulation of cellular osmolyte pools has a global effect on *** effects are mediated largely through influences of osmolytes and macromolecules on water structure and *** micromolecular responses are often critical in enabling organisms to cope with environmental changes during their lifetimes,for example,during vertical migration in the water column.A species’breadth of environmental tolerance may depend on how effectively it can vary the osmolyte composition of its cellular fluids in the face of *** adaptations remain an under-appreciated aspect of evolution and *** study can lead to a better understanding of determinants of environmental tolerance ranges and to biotechnological advances in designing improved stabilizers for biological materials.

关键词： Adaptation Crowding Extremophiles Hydrostatic pressure Osmolytes Temperature

Corticosteroid-free immunosuppression in liver transplantation: An evidence-based review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2014年第31期20卷 10703-10714页

作者： george Sgourakis Georgia Dedemadi 2~(nd) Surgical Department and Surgical Oncology Unit "Korgialenio-Benakio" Red Cross Hospital Surgical Department of "Amalia Fleming" General Hospital

Thirty-six randomized controlled trials and two metaanalyses were reviewed. With respect to adult patients undergoing first orthotopic liver transplantation(OLT), steroid replacement resulted in fewer cases of overall acute rejection in the corticosteroid free-immunosuppression arm. Initial steroid administration for two weeks and early tacrolimus monotherapy is a feasible immunosuppression regimen without steroid replacement, although further investigations are needed in view of chronic rejections. No significant differences were noted between the treatment groups in terms of patient and graft survival independently of steroid replacement. Renal insufficiency, de novo hypertension, neurological disorders and infectious complications did not differ significantly among steroid and steroidfree groups. Diabetes mellitus, cholesterol levels and cytomegalovirus infection are more frequent in patients within the steroid group. With respect to diabetes mellitus and hypercholesterolemia, the difference was independent of steroid replacement. In relation to transplanted hepatitis C virus patients, mycophenolate mofetil does not appear to have a significant antiviral effect despite early reports. Male gender of donors and recipients, living donors, cold ischemia times, acute rejection, and early histological recurrence were related to the development of advanced hepatitis. There is sufficient scientific clinical evidence advocating avoidance of the ab initio use of steroids in OLT.

关键词： Meta-analysis Evidence based Hepatitis C virus recurrence Liver transplantation Steroid withdrawal Orthotopic liver transplantation

Silicon prepared by electro-reduction in molten salts as new energy materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2020年第8期29卷 46-61,I0002页

作者： Tingting Jiang Xinyi Xu george Z.Chen The State Key Laboratory of Refractories and Metallurgy College of Materials and MetallurgyWuhan University of Science and TechnologyWuhan 430081HubeiChina Electrochemical Technologies Group Faculty of EngineeringUniversity of NottinghamNottingham NG27RDUK Electrochemical Technologies Group Faculty of Science and EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100ZhejiangChina

Silicon has a large impact on the energy supply and economy in the modern world. In industry, high purity silicon is firstly prepared by carbothermic reduction of silica with the produced raw silicon being further refined by a modified Siemens method. This process suffers from the disadvantages of high cost and contaminant release and emission. As an alternative, the molten salt electrolysis approach, particularly the FFC Cambridge Process(FFC: Fray-Farthing-Chen), could realize high purity silicon products with morphology-controllable nanostructures at low or mild temperatures(generally 650–900 ℃). In this article, we review the development, reaction mechanisms, and electrolysis conditions of silicon production by the FFC Cambridge Process. Applications of the silicon products from electrolysis in molten salts are also discussed in terms of energy applications, including using them as the photovoltaic element in solar cells and as the charge storage phase in the negative electrode(negatrode) of lithium ion batteries.

关键词： Electrolysis Molten salt Silicon Nanomaterial Li ion battery Solar cell

Stable non-synonymous substitutions on NS gene (NS1 and NS2 proteins) of Qinghai lake H5N1 influenza virus (Clade 2.2) after successive passages in Muscovy ducks

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2009年第9期52卷 847-853页

作者： GAO george F. Key Laboratory of Pathogenic Microbiology and Immunology of CAS (CASPMI) Institute of Microbiology Chinese Academy of Sciences (CAS) China-Japan Joint Laboratory of Molecular Immunology and Molecular Microbiology Institute of Microbiology Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Beijing Institutes of Life Science Chinese Academy of Sciences

Although worldwide concern has been raised since the large-scale outbreak of highly pathogenic avian influenza in wild birds at Qinghai Lake,China in 2005,the factors responsible for the ability to kill waterfowl remain unclear. The why and how questions of the H5N1 virus species-jump into its reservoir host need to be answered. In this report we test the pathogenicity and adaptation of Qinghai Lake (Clade 2.2) isolate to Muscovy ducks for further understanding of this virus. The isolate was highly pathogenic in ducks and retained its high pathogenicity even after 20 generations of passage in ducks. During the process of serial passages,only the NS gene developed non-synonymous substitutions,which caused two mutations in NS1 protein (Val23Ala and Leu207Pro) and one in NS2 (Phe55Leu). These mutations persisted immutably through all subsequent passages and the pathogenicity remained high,implying that highly pathogenic H5N1 virus remains stable in aquatic birds through oral transmission. Although the exact functions of these mutations are not known,our results provide an important foundation for further understanding the characteristics of the Qinghai Lake isolates.

关键词： avian influenza virus H5N1 mutation NS1/2 serial passages

Studies on the co-metabolism of glucose and glycerol in the fungus Umbelopsis isabellina

在线全文

学校读者我要写书评

暂无评论

Carbon Resources Conversion 2023年第4期6卷 326-333页

作者： Panagiotis Dritsas george Aggelis Unit of Microbiology Section of GeneticsCell and Developmental BiologyDepartment of BiologyUniversity of Patras26504 PatrasGreece

Over the past few years,it is observed an increased interest for oleaginous microorganisms in the perspective to produce microbial oils of great commercial interest through the consumption of low/zero cost *** this paper,the physiology of the fungus Umbelopsis isabellina growing on blends of glycerol and glucose was *** all experiments the fungus completely consumed glucose and produced satisfactory quantities of biomass containing reserve lipids in high ***,glycerol concentration in the growth medium was negatively correlated to glucose assimilation rate,mainly during the balanced-growth ***,at high initial concentrations,glycerol was partially consumed and seemed to contribute positively to the suppression of lipid *** the discovery of this complex regulatory mechanism regarding glucose and glycerol co-assimilation,the activity of three key-enzymes namely aldolase,glycerol kinase and glycerol dehydrogenase,which are implicated in glycerol and glucose assimilation,was *** experiments revealed a clear preference of the fungus for glucose over *** the other hand,storage polysaccharides are degraded instead of storage lipid at the late oleaginous phase for maintenance *** new biochemical features will enable the design of appropriate growth media for the co-fermentation of these two substrates by *** with the aim to maximize lipid accumulation.

关键词： Oleaginous microorganisms Umbelopsis isabellina Glucose and glycerol co-assimilation Aldolase Glycerol kinase Glycerol dehydrogenase

Understanding supercapacitors based on nano-hybrid materials with interfacial conjugation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2013年第3期23卷 245-255页

作者： george Z.Chen Department of Chemical and Environmental Engineering and Energy and Sustainability Research DivisionFaculty of EngineeringUniversity of NottinghamNottingham NG7 2RDUK

The recent fast development of supercapacitors,also known scientifically as electrochemical capacitors,has benefited significantly from synthesis,characterisations and electrochemistry of ***,the principle of supercapacitors is explained in terms of performance characteristics and charge storage mechanisms,*** layer(or interfacial) capacitance and *** semiconductor band model is applied to qualitatively account for the pseudo-capacitance in association with rectangular cyclic voltammograms(CVs) and linear galvanostatic charging and discharging plots(GCDs),aiming to differentiate supercapacitors from rechargeable *** invalidity of using peak shaped CVs and non-linear GCDs for capacitance measurement is highlighted.A selective review is given to the nano-hybrid materials between carbon nanotubes and redox active materials such as electronically conducting polymers and transition metal oxides.A new concept,"interfacial conjugation",is introduced to reflect the capacitance enhancement resulting from π-π stacking interactions at the interface between two materials with highly conjugated chemical *** prospects of carbon nanotubes and graphenes for supercapacitor applications are briefly compared and ***,this article can help readers to understand supercapacitors and nano-hybrid materials so that further developments in materials design and synthesis,and device engineering can be more efficient and objective.

关键词： Supercapacitors Carbon nanotubes Graphenes Electronically conducting polymers Transition metal oxides Interfacial conjugation

REGULARITY AND RECURRENCE OF SWITCHING DIFFUSIONS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2007年第2期20卷 273-283页

作者： george YIN Chao ZHU Department of Mathematics Wayne State University Detroit Michigan 48202 U.S.A.

This work is concerned with switching diffusion processes, also known as regime-switching diffusions. Our attention focuses on regularity, recurrence, and positive recurrence of the underlying stochastic processes. The main effort is devoted to obtaining easily verifiable conditions for the aforementioned properties. Continuous-state-dependent jump processes are considered. First general criteria on regularity and recurrence using Liapunov functions are obtained. Then we focus on a class of problems, in which both the drift and the diffusion coefficients are ＂linearizable＂ with respect to the continuous state, and suppose that the generator of the jump part of the process can be approximated by a generator of an ergodic Markov chain. Sufficient conditions for regularity, recurrence, and positive recurrence are derived, which are linear combination of the averaged coefficients （averaged with respect to the stationary measure of the Markov chain）.

关键词： Recurrence regularity switching diffusion

Hybrid competitive Lotka–Volterra ecosystems with a hidden Markov chain

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Control and Decision 2014年第1期1卷 51-74页

作者： Ky Tran george Yin Department of Mathematics Wayne State UniversityDetroitMIUSA

This work concerns Lotka–Volterra models that are formulated using stochastic differential equations with *** from the existing formulations,the Markov chain that models random environments is *** such partially observed systems,we use Wonham’s filter to estimate the Markov chain from the observable evolution of the population,and convert the original system to a completely observable *** then show that the positive solution of our model does not explode in finite time with probability *** properties including stochastic boundedness,finite moments,sample path continuity and large-time asymptotic behaviour are also ***,stochastic permanence,extinction and feedback controls are also investigated.

关键词： Lotka-Volterra model hidden Markov chain partially observed system

Numerical Solutions for Optimal Control of Stochastic Kolmogorov Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2021年第5期34卷 1703-1722页

作者： YIN george WEN Zhexin QIAN Hongjiang NGUYEN Huy Department of Mathematics University of ConnecticutStorrsCT 06269USA School of Mathematics and Statistics Central South UniversityChangsha 410083China Department of Mathematics Wayne State UniversityDetroitMI 48202USA

This work is concerned with controlled stochastic Kolmogorov *** systems have received much attention recently owing to the wide range of applications in biology and *** with the basic premise that the underlying system has an optimal control,this paper is devoted to designing numerical methods for *** from the existing literature on numerical methods for stochastic controls,the Kolmogorov systems take values in the first *** is,each component of the state is *** work is designing an appropriate discrete-time controlled Markov chain to be in line with(locally consistent)the controlled *** authors demonstrate that the Kushner and Dupuis Markov chain approximation method still *** of the numerical scheme is proved under suitable conditions.

关键词： Controlled diffusion controlled Markov chain Kolmogorov equation numerical approximation