检索结果-南通市图书馆

Horticulture Research 2014年第1期1卷 198-205页

作者： steve van Nocker Susan E Gardiner Department of Horticulture Michigan State UniversityEast LansingMI 48824 The New Zealand Institute for Plant&Food Research Limited Plant and Food Research Palmerston North Private Bag 11030 Manawatu Mail Centre Palmerston North4442New Zealand

Woody perennial plants,including trees that produce fruits and nuts of horticultural value,typically have long breeding cycles,and development and introduction of improved cultivars by plant breeders may require many breeding cycles and dozens of ***,recent advances in biotechnologies and genomics have the potential to accelerate cultivar development greatly in all *** mini-review summarizes approaches to reduce the number and the duration of breeding cycles for horticultural tree crops,and outlines the challenges that remain to implement these into efficient breeding pipelines.

关键词： cultivar breeding crops

PTOX Mediates Novel Pathways of Electron rransport in Etioplasts of Arabidopsis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2016年第9期9卷 1240-1259页

作者： Sekhar Kambakam Ujjal Bhattacharjee Jacob Petrich steve Rodermel Department of Genetics Development and Cell Biology iowa State University 445 Bessey Hall Ames IA 50011 USA Department of Chemistry Iowa State University Ames IA 50011 USA

The immutans （im） variegation mutant of Arabidopsis defines the gene for PTOX （plastid terminal oxidase）, a versatile plastoquinol oxidase in chloroplast membranes. In this report we used im to gain insight into the function of PTOX in etioplasts of dark-grown seedlings. We discovered that PTOX helps control the redox state of the plastoquinone （PQ） pool in these organelles, and that it plays an essential role in etioplast metabolism by participating in the desaturation reactions of carotenogenesis and in one or more redox pathways mediated by PGR5 （PROTON GRADIENT REGULATION 5） and NDH （NAD（P）H dehydrogenase）, both of which are central players in cyclic electron transport. We propose that these elements couple PTOX with electron flow from NAD（P）H to oxygen, and by analogy to chlororespiration （in chloroplasts） and chromorespiration （in chromoplasts）, we suggest that they define a respiratory process in etioplasts that we have termed ＂etiorespiration＂. We further show that the redox state of the PQ pool in etioplasts might control chlorophyll biosynthesis, perhaps by participating in mechanisms of retrograde （plastid- to-nucleus） signaling that coordinate biosynthetic and photoprotective activities required to poise the etioplast for light development. We conclude that PTOX is an important component of metabolism and redox sensing in etioplasts.

关键词： immutans PTOX etiorespiration phytoene prochlorophyllide retrograde singnaling

Fourier coefficients of restrictions of eigenfunctions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2023年第8期66卷 1849-1878页

作者： Emmett L.Wyman Yakun Xi steve Zelditch Department of Mathematics University of RochesterRochesterNY 14627USA School of Mathematical Sciences Zhejiang UniversityHangzhou 310027China Department of Mathematics Northwestern UniversityEvanstonIL 60208USA

Let{e_(j)}be an orthonormal basis of Laplace eigenfunctions of a compact Riemannian manifold(M,g).Let H■M be a submanifold and{ψ_(k)}be an orthonormal basis of Laplace eigenfunctions of H with the induced *** obtain joint asymptotics for the Fourier coefficientsL^(2)(H)=∫He_(j),ψ_(k)dV_(H)of restrictionsγHe_(j)of e_(j)to *** particular,we obtain asymptotics for the sums of the norm-squares of the Fourier coefficients over the joint spectrum{(μ_(k),λ_(j))}^(∞)_(j,k-0)of the(square roots of the)Laplacian△_(M)on M and the Laplacian△_(H)on H in a family of suitably‘thick'regions in R^(2).Thick regions include(1)the truncated coneμ_(k)/λ_(j)∈[a,b]■(0,1)andλ_(j)≤λ,and(2)the slowly thickening strip|μ_(k)-cλ_(j)|≤w(λ)andλ_(j)≤λ,where w(λ)is monotonic and 1■w(λ)≤λ^(1/2).Key tools for obtaining the asymptotics include the composition calculus of Fourier integral operators and a new multidimensional Tauberian theorem.

关键词： eigenfunctions period integrals Kuznecov formula

A Variable Stiffness Soft Gripper Using Granular Jamming and Biologically Inspired Pneumatic Muscles

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2018年第2期15卷 236-246页

作者： Loai AI Abeach Samia Nefti-Meziani Theo Theodoridis steve Davis Autonomous Systems and Robotics Research Centre University of Salford Salford M5 4WT UK Computer Engineering Department College of Engineering Basra University Basra 61004 Iraq

As the domains, in which robots operate change the objects a robot may be required to grasp and manipulate, are likely to vary sig- nificantly and often. Furthermore there is increasing likelihood that in the future robots will work collaboratively alongside people. There has therefore been interest in the development of biologically inspired robot designs which take inspiration from nature. This paper pre- sents the design and testing of a variable stiffness, three fingered soft gripper, which uses pneumatic muscles to actuate the fingers and granular jamming to vary their stiffness. This gripper is able to adjust its stiffness depending upon how fragile/deformable the object being grasped is. It is also lightweight and low inertia, making it better suited to operation near people. Each finger is formed from a cylindrical rubber bladder filled with a granular material. It is shown how decreasing the pressure inside the finger increases the jamming effect and raises finger stiffness. The paper shows experimentally how the finger stiffness can be increased from 21 N·m^-1 to 71 N·m^-1. The paper also describes the kinematics of the fingers and demonstrates how they can be position-controlled at a range of different stiffness values.

关键词： biologically inspired robots variable stiffness actuation soft robotics soft grippers pneumatic muscles

A review of the formulation and application of the spatial equilibrium models to analyze policy

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 Forestry Research 2011年第4期22卷 671-679页

作者： Phan Sy Hieu steve Harrison The Centre for Informatics and Statistics Ministry of Agriculture and Rural Development in Vietnam No. 2 Ngoc Ha Street Ba Dinh district Hanoi Vietnam Associate Professor the School of Economics the University of Queensland Australia.

This paper reviews alternative market equilibrium models for policy analysis. The origin of spatial equilibrium models and their application to wood and wood-processing industries are described. Three mathematical programming models commonly applied to solve spatial problems - namely linear programming, non-linear programming and mixed complementary programming - are reviewed in terms of forms of objective functions and constraint equalities and inequalities. These programming are illustrated with numerical examples. Linear programming is only applied in transportation problems to solve quantities trans, ported between regions when quantities supplied and demanded in each region are already known. It is argued that linear programming can be applied in broader context to transportation problems where supply and demand quantities are unknown and are linear. In this context, linear programming is seen as a more convenient method for modelers because it has a simpler objective function and does not require as strict conditions, for instance the equal numbers of variables and equations required in mixed complementary programming. Finally, some critical insights are provided on the interpretation of optimal solutions generated by solving spatial equilibrium models.

关键词： simplex method reduced-gradient linear programming non-linear programming mixed complementary programming

Electrochemically-stimulated nanoscale mechanochemical wear of silicon

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Friction 2023年第11期11卷 2142-2152页

作者： Chen XIAO Stefan VAN VLIET Roland BLIEM Bart WEBER steve FRANKLIN Advanced Research Center for Nanolithography(ARCNL) Amsterdam 1098XGthe Netherlands Van der Waals–Zeeman Institute Institute of PhysicsUniversity of Amsterdam(UvA)Amsterdam 1098XGthe Netherlands Department of Materials Science and Engineering The University of SheffieldSheffield S13JDUK

Mechanochemical reactions at the sliding interface between a single-crystalline silicon(Si)wafer and a silica(SiO2)microsphere were studied in three environmental conditions:humid air,potassium chloride(KCl)solution,and KCl solution with an applied *** to that from humid air,mechanochemical material removal from the silicon surface increased substantially in the KCl-immersed condition,and further increased when electrochemistry was introduced into the tribological *** measuring the load dependence of the material removal rate and analyzing the results using a mechanically assisted Arrhenius-type kinetic model,the activation energy(E_(a))and the mechanical energy(E_(m)),by which this energy is reduced by mechanical activation,were compared qualitatively under different environmental *** the KCl-immersed condition,mechanochemistry may decrease the required effective energy of reactions(E_(eff)=E_(a)−E_(m))and promote material removal mainly through improved catalysis of the mechanochemical reactions facilitated by greater availability of water molecules compared to the humid air ***,the effectiveness of the mechanochemistry is *** the electrochemical condition,electrochemically-accelerated oxidation of the silicon surface was confirmed by the X-ray photoelectron spectroscopy(XPS)*** results strongly suggest that electrochemistry further stimulates mechanochemical reactions primarily by increasing the initial energy state of the surface via the facilitated formation of interfacial bonding bridges,i.e.,a surface oxidation/hydroxylation process.

关键词： spherical contact adhesive wear normal loading power law

Inverse Design of Strained Graphene Surfaces for Electron Control

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2023年第6期33卷 235-260页

作者： Francois Fillion-Gourdeau Emmanuel Lorin steve Maclean Institute for Quantum Computing University of WaterlooWaterlooOntarioCanadaN2L 3G1 School of Mathematics and Statistics Carleton UniversityOttawaCanadaK1S 5B6 Centre de Recherches Mathematiques Universite de MontrealMontrealCanadaH3T 1J4

This paper is devoted to the inverse design of strained graphene surfaces for the control of electrons in the semi-classical optical-like *** that charge carriers are described by the Dirac equation in curved-space and exploiting the fact that wave propagation can be described by ray-optics in this regime,a general computational strategy is proposed in order to find strain fields associated with a desired effective refractive index *** latter is first determined by solving semi-classical trajectories and by optimizing a chosen objective functional using a genetic ***,the graded refractive index corresponding to the strain field is obtained by using its connection to the metric component in isothermal *** coordinates are evaluated via numerical quasiconformal transformations by solving the Beltrami equation with a finite volume *** graphene surface deformation is finally optimized,also using a genetic algorithm,to reproduce the desired index of *** analytical results and numerical experiments are performed to illustrate the methodology.

关键词： Graphene isothermal coordinates Beltrami equation gravitational lens waveguide finite volume method genetic algorithm Dirac equation

Biofeedback therapy for dyssynergic defecation

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 2006年第44期12卷 7069-7074页

作者： Giuseppe Chiarioni steve Heymen William E Whitehead Gastrointestinal Rehabilitation Division Valeggio sul Mincio Hospital Azienda Ospedaliera and University of Verona Valeggio sul Mincio Italy UNC Center for Functional Gastrointestinal and Motility Disorders University of North Carolina at Chapel Hill Chapel Hill NC United states

Dyssynergic defecation is one of the most common forms of functional constipation both in children and adults; it is defined by incomplete evacuation of fecal material from the rectum due to paradoxical contraction or failure to relax pelvic floor muscles when straining to defecate. This is believed to be a behavioral disorder because *** no associated morphological or neurological abnormalities, and consequently biofeedback training has been recommended for treatment. Biofeedback involves the use of pressure measurements or averaged electromyographic activity within the anal canal to teach patients how to relax pelvic floor muscles when straining to defecate. This is often combined with teaching the patient more appropriate techniques for straining （increasing intra-abdominal pressure） and having the patient practice defecating a water filled balloon. Tn adults, randomized controlled trials show that this form of biofeedback is more effective than laxatives, general muscle relaxation exercises （described as sham biofeedback）, and drugs to relax skeletal muscles. Moreover, its effectiveness is specific to patients who have dyssynergic defecation and not slow transit constipation. However, in children, no clear superiority for biofeedback compared to laxatives has been demonstrated. Based on three randomized controlled studies in the last two years, biofeedback appears to be the preferred treatment for dyssynergic defecation in adults.

关键词： Biofeedback Constipation Pelvic floor dyssynergia Dyssynergic defecation Functional defecation disorders Randomized controlled trials

Investigation of the anisotropic confinement-dependent brittleness of a Utah coal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2021年第2期8卷 274-290页

作者： Bo-Hyun Kim Gabriel Walton Mark KLarson steve Berry CDC/NIOSH 315 E.Montgomery Ave.SpokaneWAUSA Department of Geology and Geological Engineering Colorado School of MinesGoldenCOUSA Department of Geological Engineering Montana TechButteMTUSA

Changes of failure mechanism with increasing confinement,from extensional to shear-dominated failure,are widely observed in the rupture of intact specimens at the laboratory scale and in rock *** an analysis published in 2018,both unconfined and triaxial compressive tests were conducted to investigate the strength characteristics of 84 specimens of a Utah coal,including the spalling limits,the ratio of apparent unconfined compressive strength to unconfined compressive strength(UCS),the damage characteristics,and the post-yield *** mechanical characteristics were found to be strongly anisotropic as a function of the orientation of the cleats relative to the loading direction,defined as the included angle.A total of four different included angles were used in the work performed in *** authors found that the degree of anisotropic strength differed according to the included ***,the transition from extensional to shear failure at the given confinements was not clearly *** this study,a total of 20 specimens were additionally prepared from the same coal sample used in the previous study and then tested under both unconfined and triaxial compressive *** the authors already knew the most contrasting cases of the included angles from the previous work using the four included angles,they chose only two of the included angles(0°and 30°)for this *** the triaxial compressive tests,a greater confining stress than the mean UCS was applied to the specimens in an attempt to identify the brittle-ductile transition of the *** new results have been compiled with the previous results in order to re-evaluate the confinement-dependency of the coal ***,the different confining stresses are used as analogs for different width-to-height(W/H)conditions of pillar *** the W/H ratios of the specimens were not directly considered during testing,the equivalent W/H ratios of a pillar as a function of

关键词： Utah coal Spalling limit AUCS/UCS ratio Damage characteristic Post-yield dilatancy Anisotropic

Autophagy in hepatitis C virus-host interactions:Potential roles and therapeutic targets for liver-associated diseases

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19期20卷 5773-5793页

作者： Po-Yuan Ke steve S-L Chen Institute of Biomedical Sciences Academia Sinica Department of Biochemistry and Molecular Biology Graduate Institute of Biomedical Sciencesand Molecular Medicine Research CenterCollege of MedicineChang Gung University Liver Research Center Chang-Gung Memorial Hospital PhD Program in Translational Medicine Kaohsiung Medical UniversityKaohsiung 80708 and Academia Sinica

Autophagy is a lysosome-associated,degradative process that catabolizes cytosolic components to recycle nutrients for further use and maintain cell *** C virus(HCV)is a major cause of chronic hepatitis,which often leads to end-stage liverassociated diseases and is a significant burden on worldwide public *** lines of evidence indicate that autophagy plays an important role in promoting the HCV life cycle in host ***,the diverse impacts of autophagy on a variety of signaling pathways in HCV-infected cells suggest that the autophagic process is required for balancing HCVhost cell interactions and involved in the pathogenesis of HCV-related liver ***,the detailed molecular mechanism underlying how HCV activates autophagy to benefit viral growth is still ***,how the autophagic response contributes to disease progression in HCV-infected cells remains largely ***,in this review,we overview the interplay between autophagy and the HCV life cycle and propose possible mechanisms by which autophagy may promote the pathogenesis of HCVassociated chronic liver ***,we outline the related studies on how autophagy interplays with HCV replication and discuss the possible implications of autophagy and viral replication in the progression of HCV-induced liver diseases,e.g.,steatosis and hepatocellular ***,we explore the potential therapeutics that target autophagy to cure HCV infection and its related liver diseases.

关键词： Autophagy Hepatitis C virus Steatosis Cirrhosis Hepatocellular carcinoma