检索结果-南通市图书馆

Acta Geologica Sinica(English Edition) 2016年第S1期90卷 31-33页

作者： David A.D.evans Dep't.of Geology & Geophysics Yale University

The iconic image of a giant radiating dyke swarm subsequently fragmented into three pieces via supercontinental breakup was produced by Paul May in1971(see next page).That figure presented a large part of

关键词： and Contrasting Basement Geological Provinces Long-Lived Lips Advancing beyond May 1971 How Do We Deal with the Possibility of Complicated Dyke Geometries

Animal models of amyotrophic lateral sclerosis： a comparison of model validity

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2018年第12期13卷 2050-2054页

作者： Jessica R.Morrice Cheryl Y.Gregory-evans Christopher A.Shaw Experimental Medicine Program University of British Columbia Vancouver Canada Department of Ophthalmology and Visual Sciences University of British Columbia Vancouver Canada Neuroscience Program University of British Columbia Vancouver Canada Department of Pathology. University of British Columbia Vancouver Canada

Animal models are necessary to investigate the pathogenic features underlying motor neuron degeneration and for therapeutic development in amyotrophic lateral sclerosis（ALS）. Measures of model validity allow for a critical interpretation of results from each model and caution from over-interpretation of experimental models. Face and construct validity refer to the similarity in phenotype and the proposed causal factor to the human disease, respectively. More recently developed models are restricted by limited phenotype characterization, yet new models hold promise for novel disease insights, thus highlighting their importance. In this article, we evaluate the features of face and construct validity of our new zebrafish model of environmentally-induced motor neuron degeneration and discuss this in the context of current environmental and genetic ALS models, including C9 orf72, mutant Cu/Zn superoxide dismutase 1 and TAR DNA-binding protein 43 mouse and zebrafish models. In this mini-review, we discuss the pros and cons to validity criteria in each model. Our zebrafish model of environmentally-induced motor neuron degeneration displays convincing features of face validity with many hallmarks of ALS-like features, and weakness in construct validity. However, the value of this model may lie in its potential to be more representative of the pathogenic features underlying sporadic ALS cases, where environmental factors may be more likely to be involved in disease etiology than single dominant gene mutations. It may be necessary to compare findings between different strains and species modeling specific genes or environmental factors to confirm findings from ALS animal models and tease out arbitrary strain-and overexpression-specific effects.

关键词： amyotrophic lateral sclerosis motor neuron degeneration face validity construct validity zebrafish models mouse models genetic models environmental models

From contraction to gene expression:nanojunctions of the sarco/endoplasmic reticulum deliver site-and function-specific calcium signals

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2016年第8期59卷 749-763页

作者： A.Mark evans Nicola Fameli Oluseye A.Ogunbayo Jingxian Duan Jorge Navarro-Dorado Centre for Integrative Physiology College of Medicine and Veterinary MedicineHugh Robson BuildingUniversity of EdinburghEdinburgh EH8 9XDUK Institute of Biophysics Medical University of GrazGraz 8010Austria

Calcium signals determine, for example, smooth muscle contraction and changes in gene expression. How calcium signals select for these processes is enigmatic. We build on the "panjunctional sarcoplasmic reticulum" hypothesis, describing our view that different calcium pumps and release channels, with different kinetics and affinities for calcium, are strategically positioned within nanojunctions of the SR and help demarcate their respective cytoplasmic nanodomains. SERCA2 b and Ry R1 are preferentially targeted to the sarcoplasmic reticulum(SR) proximal to the plasma membrane(PM), i.e., to the superficial buffer barrier formed by PM-SR nanojunctions, and support vasodilation. In marked contrast, SERCA2 a may be entirely restricted to the deep, perinuclear SR and may supply calcium to this sub-compartment in support of vasoconstriction. Ry R3 is also preferentially targeted to the perinuclear SR, where its clusters associate with lysosome-SR nanojunctions. The distribution of Ry R2 is more widespread and extends from this region to the wider cell. Therefore, perinuclear Ry R3 s most likely support the initiation of global calcium waves at L-SR junctions, which subsequently propagate by calcium-induced calcium release via Ry R2 in order to elicit contraction. Data also suggest that unique SERCA and Ry R are preferentially targeted to invaginations of the nuclear membrane. Site- and function-specific calcium signals may thus arise to modulate stimulus-response coupling and transcriptional cascades.

关键词： calcium nanojunction ryanodine receptor sarco/endoplasmic reticulum calcium ATPase smooth muscle gene expression contraction

Synthesis of a-SnWO_4 thin-film electrodes by hydrothermal conversion from crystalline WO_3

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2015年第4期26卷 474-478页

作者： Kayla J.Pyper Taylor C.evans Bart M.Bartlett Department of Chemistry University of Michigan

Thin film electrodes of the orthorhombic form of tin tungstate （α-SnWO4） were prepared using a hydrothermal method to convert thin films of WO3 in aqueous SnCI2. The pH dependence of the growth mechanism was identified by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The XRD patterns show complete conversion of WO3（s） to SnWO4（s） at pH 1, 4, and 7. SEM images reveal a morphology change from sponge-like platelets to sharp nanowires as the pH increases from 1 to 7. The α-SnWO4 thin films were reddish brown in color, and display an indirect band gap of 1.9 eV by diffuse reflectance UV-vis spectroscopy. α-SnWO4 is therefore solar-responsive, and a chopped light linear sweep voltammogram recorded under 100 mW/cm2 AM1.5 simulated solar illumination in a pH 5 0.1 mol/L KPi buffer show a visible light response for photoelectrochemical water oxidation, producing 32 μA/cm2 at 1.23 V vs. RHE.

关键词： Alpha tin tungstateHydrothermal conversionMicrostructureHydrothermal method

The evolution of lower extremity reconstruction

在线全文

学校读者我要写书评

暂无评论

Plastic and Aesthetic Research 2022年第1期9卷 182-195页

作者： Brogan G.A.evans David L.Colen Division of Plastic and Reconstructive Surgery Department of SurgeryYale School of MedicineNew HavenCT 06510USA

Reconstruction of the lower extremity is a complex task that has evolved greatly in both technique and indication over the past *** advances in treating traumatic lower extremity injuries focused on primary amputation to avoid the high mortality of *** introduction of antibiotics improved surgical debridement and local reconstructive options,enhancing the viability of lower extremities with simple and proximal *** the advent of microvascular surgery,free tissue transfer techniques provided a means to reconstruct more distal and complex *** these surgical techniques have continued to evolve,so too have indications for reconstruction,patient management and post-operative care-now with a greater emphasis on patient quality of life and limb *** purpose of this article is to outline the evolution of lower extremity reconstruction,and how the standard of practice has changed over time.

关键词： Lower extremity lower extremity reconstruction limb salvage free flap perforator flap vascularized bone flap orthoplastic surgery

Effect of baffles on performance of fluid catalytic cracking riser

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2018年第3期16卷 18-30页

作者： Milinkumar T. Shah Vishnu K. Pareek Geoffrey M. evans Ranjeet P. Utikar Department of Chemical Engineering Curtin University Western Australia Australia Department of Chemical Engineering University of Newcastle New South Wales Australia

Increasing demand of automobile fuel and a need to process heavier crude oil makes it imperative to find improvements to the design of existing fluid catalytic cracking （FCC） units. Several modifications to the design of the riser section of FCC units have been suggested in previous studies including： improved feed nozzle designs, multiple nozzle configurations, internal baffles, and novel two-stage-riser systems. In this study, we investigate the effects of baffles on the performance of FCC risers using computational fluid dynamics simulations. In this study, predictions from a basis model （without baffles） are compared with those from four different configurations including：（i） 5-cm baffles at 5-m spacing, （ii） 7.5-cm baffles at 5- m spacing, （iii） 10-cm baffles with 5-m spacing, （iv） lO-cm baffles at 2.5-m spacing, and （v） lO-cm baffles at 1-m spacing. The baffles force the catalyst away from wails toward the center of the riser, enhancing the radial dispersion of the catalyst and the heat transfer inside the riser. The use of longer baffles and smaller spacings further increases the dispersion, yielding more homogeneous radial profiles. The changes in the radial dispersion result in variations in the conversion, yields, and pressure drops. The baffles increase conversion of vacuum gas oil （VGO） and the yield of gasoline. However, the simulations showed that longer baffles and a larger number of baffles did not always give a higher yield or higher conversion. Among the simulated configurations, the 5-cm baffles at 5-m spacing gave the highest conversion of VGO, whereas the 10-cm baffles at 1 -m spacing resulted in the highest yield of the gasoline. Thus, rational optimization of baffle configurations is required to achieve optimal performance.

关键词： Fluid catalytic cracking Riser Baffles Computational fluid dynamics

Theoretical Analysis of the Fluctuation Theorem Applied to Electric Circuits

维普期刊数据库评论

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 Theoretical Physics 2014年第10期61卷 476-484页

作者： Charlotte F.Petersen Elmars Krausz Denis J.evans Stephen R.Williams Research School of Chemistry Australian National UniversityCanberraACT 0200Australia

We carry out a theoretical analysis of the fluctuations in the Johnson–Nyquist noise in an RC electric circuit being driven by a non-ideal constant current source. Using the appropriate Langevin equation, we derive the fluctuation theorem for the system. This analysis exhibits some interesting features. Firstly, the average of the dissipation function is not necessarily just an instantaneous entropy production, i.e. the work being done on the circuit by the external power source divided by the ambient temperature. Secondly, by appropriate selection of the values for the circuit components,the transient response of the system can be made identical to the nonequilibrium steady state response. In the limit of an ideal current source, the average of the dissipation function reduces to the entropy production. Our analysis accurately reproduces published experimental results.

关键词： circuit analysis fluctuation theorems statistical machanics Johnson noise

Studies of the Catalytic Activity and Deactivation of Calcined Layered Double Hydroxides in the Reaction of Ethanol with Propylene Oxide

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2002年第2期18卷 192-195页

作者： JIAO Qing ze ZHAO Yun ZHANG Yi qing evans DG DUAN Xue ZHOU Zi-niu The Key Laboratory of Science and Technology of Controllable Chemical Reactions Ministry of EductionBeijing University of Chemical TechnologyBeijing 100029P.R.China Yixing Auxiliary Chemicals Plant Jiangsu 214262P.R.China

The reaction of ethanol with propylene oxide over calcined layered double hydroxides(CLDH) was investigated. The results show that CLDH has a good activity and a good selectivity, but the activity and the selectivity of CLDH decrease when CLDH reforms LDH- the so called 'memory effect'. The influence of the 'memory effect' on the CLDH returning to LDH was studied by the hydration reaction. It is shown that the 'memory effect' is not complete, and the decreases of the Mg/Al molar ratio of LDH and the crystallite size due to the increase of the hydration reaction time result in the drop of the activity and the selectivity.

关键词： Ethanol, Propylene oxide Calcined layered double hydroxide 'Memory effect' Hydration

Flow of Steel in Mold Region During Continuous Casting

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2007年第2期14卷 30-35,41页

作者： ZHANG Xing-guo ZHANG Wen-xiao JIN Jun-ze J. W. evans Research Center of Foundry Engineering Dalian University of Technology Dalian 116023 Liaoning China Department of Material Science and Engineering University of California at Berkeley Berkeley CA94720 USA

The particle image velocimetry （PIV） technique was used to study the fluid flow phenomena that occurred during continuous casting, using a water model with dimensions of 1 840mm× 280 mm. Two types of solidified shells, i. e. , the smooth type and the coarse type, were used to characterize the dendrite in order to simulate different liquid-solid interfacial conditions. The influence of the nozzle angle and the immersion depth of nozzle, as well as the casting speed on the flow behavior was investigated quantitatively. The results were as follows：（1） There are two large recirculations above and below the fluid jet in the mold, respectively, under the smooth interface condition. However, in the case of the dendrite solidified shell, it was found that the flow velocity of the fluid decreased and more smaller vortices appeared in the upper region of the mold. （2） The angle and the immersion depth of nozzle are two important factors affecting the flow pattern, and they are also capable of bringing about the change in the flow direction. （3） The higher the casting speed, the higher are the jet stream and the impacting point on the narrow face. However, the high casting speed causes serious fluctuation of the meniscus, and correspondingly leads to various defects.

关键词： particle image velocimetry continuous casting steel fluid flow

Structure and Combustion Characteristics of Methane/Air Premixed Flame under the Action of Wall

在线全文

学校读者我要写书评

暂无评论

Energy Engineering 2021年第4期118卷 1135-1154页

作者： Feiyang Li Jianfeng Pan Chenxin Zhang evans K.Quaye Xia Shao School of Energy and Power Engineering Jiangsu UniversityZhenjiang212013China

In order to obtain the combustion characteristics of the CH4/Air premixed flame under the action of the wall interaction,a study on the impact of the jet flame on the wall at different separation distances was carried *** separation distance from the burner outlet to the lower surface of the wall is changed and the flame structure is obtained through *** temperature,velocity and reaction rate are obtained through numerical simulation,and the law of flame characteristics change is obtained through *** results show that as the separation distance increases,the premixing cone inside the flame gradually changes from a horn shape to a complete cone shape and the length of the premixing cone profile ***,the peak temperature and velocity of the mixture in the axial direction gradually increase,and the temperature and velocity in the radial direction first increase and then *** temperature gradient and velocity reach the maximum when the separation distance is 11 *** peaks of reactants(CH_(4))net reaction rate intermediate products(CO)and products(CO_(2),H_(2)O)on the axis and the axial distance corresponding to the peaks increase *** chemical reaction rate near the wall also gradually decreases with the increase of the separation distance.

关键词： Flame-wall interaction separation distance flame structure air flow temperature flow velocity reaction rate