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Physical characteristics of conditioned anaerobic digested sludge-A fractal, transient and dynamic rheological viewpoint

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Journal of Environmental Sciences 2011年第8期23卷 1266-1273页

作者： Yili Wang Emilie Dieude-Fauvel steven K Dentel College of Environmental Science and Engineering Beijing Forestry University Beijing 100083 China. Department of Civil and Environmental Engineering University of Delaware Newark Delaware 19711 USA Cemagref Les Palaquins 03150 Montoldre Paris France

The changes in the physical characteristics of unconditioned and conditioned anaerobic digested sludge （ADS） biosolids, such as capillary suction time （CST）, yield stress, average size and fractal dimensions, were investigated through a CST test, transient and dynamic rheological test and image analysis. The results showed that the optimum polymer dose range was observed when CST or its reciprocal value was employed as an indicator. There were good correlations between the yield stresses determined from both a controlled shear stress test and a strain amplitude sweep test. The yield stress and storage modulus （G＇） increased as the polymer dose increased in most cases. A frequency sweep test revealed that polymer conditioning could extend the frequency sweep ranges for their elastic behaviors over viscous behaviors as well as the gel-like structure in the linear viscoelastic range. These results implied that more deformation energy was stored in this rigid structure, and that elastic behavior became increasingly dominant with the addition of the polymer in most cases, In addition, both the average sizes and two-dimensional fractal dimensions for conditioned ADS biosolids presented a similar up-climax-down variation trend as the polymer doses increased, whereas the critical polymer doses at the highest average sizes or two-dimensional fractal dimensions, were different. Correlation analysis revealed that the conditioned ADS dewaterability was not correlated with the yield stresses, while the average sizes or the two-dimensional fractal dimensions for conditioned ADS biosolids could be taken as the indication parameters for ADS dewaterability.

关键词： anaerobic digested sludge conditioning dynamic oscillatory test yield stress fractal dimensions polymer dose

H_∞ fault estimation for a class of linear time-delay systems in finite frequency domain

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Journal of Systems Engineering and Electronics 2010年第5期21卷 835-841页

作者： Quanchao Dong Maiying Zhong steven X. Ding School of Control Science and Engineering Shandong University Jinan 250061 E R. China School of Instrumentation Science and Opto-electronics Engineering Beihang University Beijing 100191 P. R. China Institute for Automatic Control and Complex Systems University of Duisburg-Essen Duisburg 47057 Germany

This paper deals with the problem of H∞ fault estimation for linear time-delay systems in finite frequency *** a generalized coordinate change is applied to the original system such that in the new coordinates all the time-delay terms are injected by the system＇s input and *** an observer-based H∞ fault estimator with input and output injections is proposed for fault estimation with known frequency *** the aid of Generalized Kalman-Yakubovich-Popov lemma,sufficient conditions on the existence of the H∞ fault estimator are derived and a solution to the observer gain matrices is obtained by solving a set of linear matrix ***,a numerical example is given to illustrate the effectiveness of the proposed method.

关键词： fault estimation time-delay generalized coordinate change generalized Kalman-Yakubovich-Popov lemma finite frequency domain.

Compressive deformation of ultralong amyloid fibrils

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Acta Mechanica Sinica 2010年第6期26卷 977-986页

作者： Raffaella Paparcone steven Cranford Markus J.Buehler Laboratory for Atomistic and Molecular Mechanics

Involved in various neurodegenerative diseases, amyloid fibrils and plaques feature a hierarchical structure, ranging from the atomistic to the micrometer *** the atomistic level,a dense and organized hydrogen bond network is resembled in a beta-sheet rich secondary structure, which drives a remarkable stiffness in the range of 10-20GPa,larger than many other biological nanofibrils, a result confirmed by both experiment and ***, the understanding of how these exceptional mechanical properties transfer from the atomistic to the nanoscale remains *** we report a multiscale analysis that, from the atomistic-level structure of a single fibril,extends to the mesoscale level,reaching size scales of hundreds of *** use parameters directly derived from full atomistic simulations of Aβ（1-40） amyloid fibrils to parameterize a mesoscopic coarse-grained model,which is used to reproduce the elastic properties of amyloid *** then apply our mesoscopic model in an analysis of the buckling behavior of amyloid fibrils with different lengths and report a comparison with predictions from continuum beam theory. An important implication of our results is a severe reduction of the effective modulus due to buckling,an effect that could be important to interpret experimental results of ultralong amyloid *** model represents a powerful tool to mechanically characterize molecular structures on the order of hundreds of nanometers to micrometers on the basis of the underlying atomistic *** work provides insight into structural and mechanical properties of amyloid fibrils and may enable further analysis of larger-scale assemblies such as amyloidogenic bundles or plaques as found in disease states.

关键词： Amyloid Coarse-grain Molecular simulation Nanomechanics Materiomics

Effect of compressibility on bubbly cavitating flows

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Journal of Hydrodynamics 2020年第1期32卷 1-5页

作者： Harish Ganesh Anubhav Bhatt Juliana Wu steven Ceccio Department of Naval Architecture and Marine Engineering University of MichiganAnn ArborMichiganUSA

Cavitating bubbly flows can form in separated flows and shear layers leading to local regions high vapor void fraction,and these flows often exhibit periodic shedding of vaporous ***,the presence of a liquid re-entrant flow,driven by the kinematics of liquid flow stagnation,has been identified as an important mechanism leading to cavity ***,high local vapor void fractions can also result in a reduced mixture speed of sound and a possible supersonic *** recent findings on different geometries indicate that propagating bubbly shocks in these flows are a primary mechanism of flow *** this study,we discuss the effect of compressibility on four geometries,mainly in the generation of propagating bubbly shocks that can influence the cavitation shedding *** order to elucidate the differences and similarities of the observed cavitation dynamics,and the influence of compressibility,we report observations from a backward facing step,backward facing wedge,NACA0015 hydrofoil,and a bluff body with a wedge cross section.

关键词： Cavitation bubbly shocks compressible vapor-liquid flows

Multi-disciplinary approaches to water systems:introduction to the special column

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Frontiers of Earth Science 2020年第2期14卷 251-255页

作者： steven RFASSNACHT Mingguo MA ESS-Watershed Science Colorado State UniversityFort CollinsCO 80523-1476USA Cooperative Institute for Research in the Atmosphere Fort CollinsCO 80523-1375USA Natural Resources Ecology Laboratory Fort CollinsCO 80523-1499USA Research Base of Karst Eco-environments at Nanchuan in Chongqing Ministry of Nature ResourcesSchool of Geographical SciencesSouthwest UniversityChongqing 400715China

1 Introduction As the human population grows,the livelihoods and well-being of a significant portion of humanity will depend even more on the ability of freshwater ecosystems to provide essential services(Vörösmarty et al.,2010),which will require the maintenance of biodiversity in these freshwater systems(Dudgeon et al.,2006).There are many competing demands on the available water resources,such as potable water,fish and wildlife habitat,agriculture,industrial use,and recreation,that are driven by different sectors;even within a specific sector there can be diverging *** example,water management of the Upper Arkansas River in Colorado has been mandated by the 1949 Arkansas River Compact between the US states of Colorado and Kansas which has led to stream-aquifer issues(Taylor and Luckey,1974),water transfers from agriculture to urban(Howe et al.,1990),and competing recreational uses(Wollmuth et al.,1985;Arkansas Basin Roundtable,2017).The recent Upper Arkansas Voluntary Flow Management Program tries to balance many users,including recreation by kayakers and rafters who want to maintain streamflow(at the Wellsville gauge)at or greater than 20 m3/s as well as anglers who want lower flows in the range of 7 to 11 m3/s to maintain fish habitat(Arkansas Basin Roundtable,2017).

关键词： Upper habitat maintain

Current status of laparoscopy for the treatment of rectal cancer

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World Journal of Gastroenterology 2014年第41期20卷 15125-15134页

作者： Noam Shussman steven D Wexner Department of Colorectal Surgery Cleveland Clinic Florida

Surgery for rectal cancer in complex and entails many *** the laparoscopic approach in general and specific to colon cancer has been long proven to have short term benefits and to be oncologically safe,it is still a debatable topic for rectal *** attempt to benefit rectal cancer patients with the known advantages of the laparoscopic approach while not compromising their oncologic outcome has led to the conduction of many studies during the past *** we describe our technique for laparoscopic proctectomy and assess the current literature dealing with short term outcomes,immediate oncologic measures(such as lymph node yield and specimen quality) and long term oncologic outcomes of laparoscopic rectal cancer *** also briefly evaluate the evolving issues of robotic assisted rectal cancer surgery and the current innovations and trends in the minimally invasive approach to rectal cancer surgery.

关键词： Laparoscopy Rectal cancer Minimally invasive surgery Oncological outcomes Short term benefits

Current methods for the maturation of induced pluripotent stem cellderived cardiomyocytes

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World Journal of Stem Cells 2019年第1期11卷 33-43页

作者： Pranav Machiraju steven C Greenway Departments of Pediatrics and Cardiac Sciences Alberta Children’s Hospital Research Institute Libin Cardiovascular Institute of Alberta Cumming School of MedicineUniversity of Calgary Departments of Pediatrics Cardiac Sciences Biochemistry & Molecular Biology Alberta Children’s Hospital Research Institute Libin Cardiovascular Institute of Alberta Cumming School of Medicine University of Calgary

Induced pluripotent stem cells(iPSCs) were first generated by Yamanaka and colleagues over a decade ago. Since then, iPSCs have been successfully differentiated into many distinct cell types, enabling tissue-, disease-, and patientspecific in vitro modelling. Cardiovascular disease is the greatest cause of mortality worldwide but encompasses rarer disorders of conduction and myocardial function for which a cellular model of study is ideal. Although methods to differentiate iPSCs into beating cardiomyocytes(iPSC-CMs) have recently been adequately optimized and commercialized, the resulting cells remain largely immature with regards to their structure and function,demonstrating fetal gene expression, disorganized morphology, reliance on predominantly glycolytic metabolism and contractile characteristics that differ from those of adult cardiomyocytes. As such, disease modelling using iPSC-CMs may be inaccurate and of limited utility. However, this limitation is widely recognized, and numerous groups have made substantial progress in addressing this problem. This review highlights successful methods that have been developed for the maturation of human iPSC-CMs using small molecules,environmental manipulation and 3-dimensional(3 D) growth approaches.

关键词： Induced pluripotent stem cells Induced pluripotent stem cell-derived cardiomyocytes Regenerative medicine Stem cell biology Translational research

Long-term antifibrotic action of interferon-γ treatment in patients with chronic hepatitis B virus infection

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Hepatobiliary & Pancreatic Diseases International 2011年第2期10卷 151-157页

作者： Peter R Mertens steven Dooley Department of Nephrology and Hypertension Otto-von-Guericke-University First Affiliated Hospital Zhejiang University School of Medicine Molecular Hepatology-Alcohol Dependent Diseases II. Medical Clinic Faculty of Medicine at MannheimUniversity of Heidelberg

BACKGROUND:The first priority in treating fibrosis is to eliminate the causes that result in liver injury,e.g.,hepatitis B and C ***,in many liver diseases the cause is either unknown or *** present study was designed to investigate the long-term antifibrotic effect of interferon-gamma(IFN-γ)treatment in patients chronically infected with hepatitis B virus. METHODS:A total of 42 patients,30 treated with IFN-γand 12 controls,were enrolled from an original clinical trial(Clin Gastroenterol Hepatol 2005;3:819.).Three serial liver biopsies that were obtained at the initiation and end of IFN-γtreatment as well as 4 to 6 years after treatment discontinuation were assessed according to the modified Chevallier scoring system. RESULTS:Twenty-five out of 30 IFN-γ-treated patients were followed up until 4 to 6 years after the treatment was stopped. However,all controls were excluded from follow-up due to death,loss and elevated virus level within 2 ***-five IFN-γ-treated patients had stable serum liver function and liver fibrosis indices without any further antiviral or anti-fibrotic *** inflammatory and fibrotic scores were found after nine months of IFN-γtreatment according to the modified Chevallier scoring system(inflammation:11.8±6.5 at the beginning of IFN-γtreatment vs.9.2±4.1 after 9 months, P<0.05;fibrosis:15.0±7.3 at baseline vs.12.6±6.8 after 9 months, P<0.05).Among them,14 patients accepted a third serial liver biopsy 4 to 6 years after treatment discontinuation,and the fibrotic score was increased(14.2±8.3 vs.11.9±7.6 after 9 months, P<0.05). CONCLUSIONS:Nine-month IFN-γtreatment significantly improves the fibrosis score in patients with chronic HBV *** majority of patients demonstrate stable serum biochemical indices and quality of ***,they do not show a long-term benefit according to histological criteria. Given the limited sample size,long-term IFN-γtreatment regimens should be assessed in further

关键词： hepatic stellate cells hepatitis B virus liver fibrosis inflammation interferon-gamma

Strigolactones redefine plant hormones

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Science China(Life Sciences) 2016年第10期59卷 1083-1085页

作者： Lu Wang steven M.Smith School of Biological Sciences University of Tasmania Institute of Genetics and Developmental Biology Chinese Academy of sciences

A commonly accepted view of plant growth hormones is that their interaction with the cognate receptor protein is reversible, so that each hormone molecule can potentially interact multiple times with a receptor and so either amplify the hormone signal or maintain it over an extended period of time. The signal can be ＇cancelled＇ by degrading the hormone. Strigolactones present us with a potentially new paradigm. The receptor is a serine hydrolase-type protein which attacks the strigolactone resulting in covalent modi- fication of the receptor, while at the same time destroying the hormone. Strigolactone is apparently a one-use ＇dispos- able＇ hormone.

关键词：植物激素受体蛋白定义植物生长激素相互作用激素信号酸水解