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Chinese Annals of Mathematics,Series B 2017年第6期38卷 1223-1246页

作者： Daciberg Lima GONCALVES john GUASCHI departamento de Matematica IME-USPRua do Matao 1010CEP:05508-090Sao PauloSPBrazil Normandie Universite UNICAENLaboratoire de Mathematiques Nicolas Oresme UMR CNRS 6139CS 1403214032 Caen Cedex 5France

Let X be a topological *** this survey the authors consider several types of configuration spaces,namely,the classical(usual)configuration spaces F_n(X)and D_n(X),the orbit configuration spaces F_n^G(X)and F_n^G(X)/S_nwith respect to a free action of a group G on X,and the graph configuration spaces F_n~Γ(X)and F_n~Γ(X)/H,whereΓis a graph and H is a suitable subgroup of the symmetric group S_*** ordered configuration spaces F_n(X),F_n^G(X),F_n~Γ(X)are all subsets of the n-fold Cartesian product ∏_1~nX of X with itself,and satisfy F_n^G(X)?F_n(X)?F_n~Γ(X)?∏_1~*** A denotes one of these configuration spaces,the authors analyse the difference between A and ∏_1~nXfrom a topological and homotopical point of *** principal results known in the literature concern the usual configuration *** authors are particularly interested in the homomorphism on the level of the homotopy groups of the spaces induced by the inclusionι:A-→∏_1~nX,the homotopy type of the homotopy fibre I_ιof the mapιvia certain constructions on various spaces that depend on X,and the long exact sequence in homotopy of the fibration involving I_ιand arising from the inclusionι.In this respect,if X is either a surface without boundary,in particular if X is the 2-sphere or the real projective plane,or a space whose universal covering is contractible,or an orbit space S^k/Gof the k-dimensional sphere by a free action of a Lie group G,the authors present recent results obtained by themselves for the first case,and in collaboration with Golasi′nski for the second and third *** authors also briefly indicate some older results relative to the homotopy of these spaces that are related to the problems of *** order to motivate various questions,for the remaining types of configuration spaces,a few of their basic properties are described and proved.A list of open questions and problems is given at the end of the paper.

关键词： Configuration space Equivariant configuration space Fibration Homotopy fibre K(π,1)space Braid groups

Update of the Chronology of Natural Signals in the Near-Surface Mean Global Temperature Record and the Southern Oscillation Index

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International Journal of Geosciences 2013年第1期4卷 234-239页

作者： Chris R. de Freitas john D. McLean department of Physics James Cook University Townsville Australia School of Environment University of Auckland Auckland New Zealand

Time series for the Southern Oscillation Index and mean global near surface temperature anomalies are compared for the 1950 to 2012 period using recently released HadCRU4 data. The method avoids a focused statistical analysis of the data, in part because the study deals with smoothed data, which means there is the danger of spurious correlations, and in part because the El Ni?o Southern Oscillation is a cyclical phenomenon of irregular period. In these situations the results of regression analysis or similar statistical evaluation can be misleading. With the potential controversy arising over a particular statistical analysis removed, the findings indicate that El Nino-Southern Oscillation exercises a major influence on mean global temperature. The results show the potential of natural forcing mechanisms to account for mean global temperature variation, although the extent of the influence is difficult to quantify from among the variability of short-term influences.

关键词： Climate Variability Southern Oscillation Index ENSO Ocean/Atmosphere Interactions Global Temperature

Generalizing J_2 flow theory: Fundamental issues in strain gradient plasticity

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Acta Mechanica Sinica 2012年第4期28卷 1078-1086页

作者： john W. Hutchinson School of Engineering and Applied Sciences Harvard University

It has not been a simple matter to obtain a sound extension of the classical J2 flow theory of plasticity that incorporates a dependence on plastic strain gradients and that is capable of capturing size-dependent behaviour of metals at the micron scale. Two classes of basic extensions of classical J2 theory have been proposed： one with increments in higher order stresses related to increments of strain gradients and the other characterized by the higher order stresses themselves expressed in terms of increments of strain gradients. The theories proposed by Muhlhans and Aifantis in 1991 and Fleck and Hutchinson in 2001 are in the first class, and, as formulated, these do not always satisfy thermodynamic requirements on plastic dissipation. On the other hand, theories of the second class proposed by Gudmundson in 2004 and Gurtin and Anand in 2009 have the physical deficiency that the higher order stress quantities can change discontinuously for bodies subject to arbitrarily small load changes. The present paper lays out this background to the quest for a sound phenomenological extension of the rateindependent J2 flow theory of plasticity to include a de- pendence on gradients of plastic strain. A modification of the Fleck-Hutchinson formulation that ensures its thermo- dynamic integrity is presented and contrasted with a comparable formulation of the second class where in the higher or- der stresses are expressed in terms of the plastic strain rate. Both versions are constructed to reduce to the classical J2 flow theory of plasticity when the gradients can be neglected and to coincide with the simpler and more readily formulated J2 deformation theory of gradient plasticity for deformation histories characterized by proportional straining.

关键词： Strain gradient plasticity deformation plasticity J2 flow theory of plasticity

Palm oil biodiesel:An assessment of PAH emissions,oxidative potential and ecotoxicity of particulate matter

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Journal of Environmental Sciences 2021年第3期33卷 326-338页

作者： Silvana Arias Francisco Molina john R.Agudelo Grupo de Investigación en Gestión y Modelación Ambiental-GAIA Escuela AmbientalFacultad de IngenieríaUniversidad de Antioquia UdeACalle 70 No.52-21MedellínColombia departamento de Ingeniería Mecánica Universidad de Antioquia UdeA

This work assessed the impact of fuelling an automotive engine with palm biodiesel(pure,and two blends of 10%and 20%with diesel,B100,B10 and B20,respectively)operating under representative urban driving conditions on 17 priority polycyclic aromatic hydrocarbon(PAH)compounds,oxidative potential of ascorbic acid(OP^(AA)),and ecotoxicity through D aphnia pulex mortality *** diluted with filtered fresh air(WD)gathered in a minitunel,and particulate matter(PM)collected directly from the exhaust gas stream(W/oD)were used for *** showed that PM collecting method significantly impact PAH *** all PAH appeared in both,WD and W/oD,higher concentrations were obtained in the last *** biodiesel concentration in the fuel blend decreased all PAH compounds,and those with 3 and 5 aromatic rings were the most *** biodiesel affected both OP^(AA)and *** B10 and B20 exhibited the same rate of ascorbic acid(AA)depletion,B100 showed significant faster oxidation rate during the first four minutes and oxidized 10%more AA at the end of the test.B100 and B20 were significantly more ecotoxic than *** lethal concentration LC50 for B10 was 6.13 mg/*** was concluded that palm biodiesel decreased PAH compounds,but increased the oxidative potential and ecotoxicity.

关键词： Biodiesel Particulate matter P emissions Oxidative stress Ecotoxicity Daphnia pulex

Highly cross-linked polyethylene is the new‘gold standard’bearing material for total hip arthroplasty

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Biosurface and Biotribology 2021年第2期7卷 53-59页

作者： john B.Medley department of Mechanical and Mechatronics Engineering University of WaterlooWaterlooOntarioCanada

Conventional polyethylene is not used much in total hip arthroplasty(THA);it has been supplanted by oxidation-resistant cross-linked polyethylene(≥50 kGy irradiation).However,studies persist that de-emphasize or ignore cross-linked polyethylene.A se-lective literature review is used briefly to present the early use of conventional poly-ethylene and its implication in wear particle-induced osteolysis leading to premature revision *** current situation is established based on Australian registry data and other studies that advocate the use of cross-linked polyethylene in preference to conventional *** some studies suggest caution in using cross-linked polyethylene,overall it is strongly *** the author’s opinion,cross-linked polyethylene is the new reference standard bearing material in THA.

关键词： cross Highly planted

An Interface-Fitted Finite Element Level Set Method with Application to Solidification and Solvation

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Communications in Computational Physics 2011年第6期10卷 32-56页

作者： Bo Li john Shopple department of Mathematics and the NSF Center for Theoretical Biological Physics University of CaliforniaSan Diego9500 Gilman DriveMail code:0112.La JollaCA 92093-0112USA department of Mathematics University of CaliforniaSan Diego9500 Gilman DriveMail code:0112.La JollaCA 92093-0112USA.

A new finite element level set method is developed to simulate the interface *** normal velocity of the moving interface can depend on both the local geometry,such as the curvature,and the external force such as that due to the flux from both sides of the interface of a material whose concentration is governed by a diffusion *** key idea of the method is to use an interface-fitted finite element *** an approximation of the interface allows an accurate calculation of the solution to the diffusion *** interface-fitted mesh is constructed from a base mesh,a uniform finite element mesh,at each time step to explicitly locate the interface and separate regions defined by the *** new level set techniques are developed in the framework of finite element *** include a simple finite element method for approximating the curvature,a new method for the extension of normal velocity,and a finite element least-squares method for the reinitialization of level set *** of the method to the classical solidification problem captures the *** method is also applied to the molecular solvation to determine optimal solute-solvent interfaces of solvation systems.

关键词： Level set method finite element interface-fitted mesh curvature approximation velocity extension reinitialization solidification dendrites molecular solvation variational implicitsolvent models

Fabrication of K-promoted iron/carbon nanotubes composite catalysts for the Fischer–Tropsch synthesis of lower olefins

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Journal of Energy Chemistry 2016年第2期25卷 309-315页

作者： Xuezhi Duan Di Wang Gang Qian john C.Walmsley Anders Holmen de Chen Xinggui Zhou State Key Laboratory of Chemical Engineering East China University of Science and Technology Shanghai 200237 China department of Chemical Engineering Norwegian University of Science and Technology 7491 Trondheim Norway SINTEF Materials and Chemistry 7465 Trondheim Norway

K-promoted iron/carbon nanotubes composite（i.e., Fe K-OX） was prepared by a redox reaction between carbon nanotubes and K2FeO4followed by thermal treatments on a purpose as the Fischer–Tropsch catalyst for the direct conversion of syngas to lower olefins. Its catalytic behaviors were compared with those of the other two Fe-IM and Fe K-IM catalysts prepared by impregnation method followed by thermal treatments. The novel Fe K-OX composite catalyst is found to exhibit higher hydrocarbon selectivity,lower olefins selectivity and chain growth probability as well as better stability. The catalyst structureperformance relationship has been established using multiple techniques including XRD, Raman, TEM and EDS elemental mapping. In addition, effects of additional potassium into the Fe K-OX composite catalyst on the FTO performance were also investigated and discussed. Additional potassium promoters further endow the catalysts with higher yield of lower olefins. These results demonstrated that the introduction method of promoters and iron species plays a crucial role in the design and fabrication of highly active,selective and stable iron-based composite catalysts for the FTO reaction.

关键词： Fischer–Tropsch synthesis Lower olefins Iron catalyst Potassium promoter Carbon nanotubes

Improved Hepascore in hepatitis C predicts reversal in risk of adverse outcome

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World Journal of Hepatology 2017年第19期9卷 850-856页

作者： Angus W Jeffrey Yi Huang W Bastiaan de Boer Leon A Adams Gerry MacQuillan David Speers john Joseph Gary P Jeffrey School of Medicine University of Notre Dame School of Medicine and Pharmacology University of Western Australia department of Hepatology Sir Charles Gairdner Hospital department of Anatomical Pathology Path West QEII Medical Centre department of Microbiology Path West QEII Medical Centre department of Biochemistry Path West QEII Medical Centre

AIM To establish if serial Hepascore tests(referred to as delta Hepascore) in those with chronic hepatitis C(CHC) correlate with the increase and/or decrease in risk of liver related *** Three hundred and forty-six CHC patients who had two Hepascore tests performed were studied. During 1944 patient years follow-up 28(8.1%) reached an endpoint. The Hepascore is a serum test that provides clinically useful data regarding the stage of liver fibrosis andsubsequent clinical outcomes in chronic liver *** Patients with a baseline Hepascore > 0.75 had a significantly increased rate of reaching a composite endpoint consisting of hepatocellular carcinoma, liver death, and/or decompensation(P 0.75, a subsequent improved Hepascore showed a significantly decreased risk for the composite endpoint(P = 0.004). There were no negative outcomes in those with a stable or improved delta Hepascore. The minimum time between tests that was found to give a statically significant result was in those greater than one year(P = 0.03).CONCLUSION In conclusion, Hepascore is an accurate predictor of liver related mortality and liver related morbidity in CHC patients. Of note, we have found that there is a decreased risk of mortality and morbidity in CHC patients when the patient has an improving delta Hepascore. Repeat Hepascore tests, when performed at a minimum one-year interval, may be of value in routine clinical practice to predict liver related clinical outcomes and to guide patient management.

关键词： Chronic Prognosis Direct acting antivirals Serum Hepatitis C

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Autoimmune hepatitis

Frontiers of Medicine 2015年第2期9卷 187-219页

作者： Farhad Sahebjam john M. Vierling departments of Medicine and Surgery Baylor College of Medicine Baylor-St. Luke's Medical Center Houston TX 77030 USA

Autoimmune hepatitis is a chronic liver disease putatively caused by loss of tolerance to hepatocyte- specific autoantigens. It is characterized by female predilection, elevated aminotransferase levels, autoantibodies, increased y-globulin or IgG levels and biopsy evidence of interface hepatitis. It is currently divided into types 1 and 2, based on expression of autoantibodies. Autoantigenic epitopes have been identified only for the less frequent type 2. Although autoimmune hepatitis occurs in childhood, this review focuses on disease in adults. In the absence of pathognomonic biomarkers, diagnosis requires consideration of clinical, biochemical, serological and histological features, which have been codified into validated diagnostic scoring systems. Since many features also occur in other chronic liver diseases, these scoring systems aid evaluation of the differential diagnosis. New practice guidelines have redefined criteria for remission to include complete biochemical and histological normalization on immunosuppressive therapy. Immunosuppression is most often successful using prednisone or prednisolone and azathioprine; however, the combination of budesonide and azathioprine for non-cirrhotic patients offers distinct advantages. Patients failing standard immunosuppression are candidates for alternative immunosuppressive regimens, yet none of the options has been studied in a randomized, controlled trial. Overlap syndromes with either primary sclerosing cholangitis or primary biliary cirrhosis occur in a minority. Liver transplantation represents a life-saving option for patients presenting with acute liver failure, severely decompensated cirrhosis or hepatocellular carcinoma. Transplant recipients are at risk for recurrent autoimmune hepatitis in the allograft, and de novo disease may occur in patients transplanted for other indications. Patients transplanted for AIH are also at risk for recurrent or de novo inflammatory bowel disease. Progress in our understa

关键词： autoimmune hepatitis autoantibodies diagnosis immunological diseases drug-induced liver injury therapy immunosuppression outcomes hepatocellular carcinoma liver transplantation