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Viscoelastic modeling of the diffusion of polymeric pollutants injected into a pipe flow

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Acta Mechanica Sinica 2013年第2期29卷 166-178页

作者： T.Chinyoka o.D. Makinde Center for Research in Computational and Applied Mechanics University of Cape Town Institute for Advanced Research in Mathematical Modeling and Computations Cape Peninsula University of Technology

This study focuses on the transient analysis of nonlinear dispersion of a polymeric pollutant ejected by an external source into a laminar pipe flow of a Newtonian liquid under axi-symmetric *** influence of density variation with pollutant concentration is approximated according to the Boussinesq approximation and the nonlinear governing equations of momentum,pollutant concentration are obtained together with and oldroyd-B constitutive model for the polymer *** problem is solved numerically using a semi-implicit finite difference *** are presented in graphical form for various parameter values and given in terms of fluid velocity,pollutant concentration,polymer stress components,skin friction and wall mass transfer *** model can be a useful tool in understanding the dynamics of industrial pollution situations arising from improper discharge of hydrocarbon pollutants into,say,water *** model can also be quite useful for available necessary early warning methods for detecting or predicting the scale of pollution and hence help mitigate related damage downstream by earlier instituting relevant decontamination measures.

关键词： Axi-symmetric flow·Polymeric pollutant dispersion·oldroyd-B model Buoyancy forces·Semi-implicit finite difference method

Making topological protein links using enzymatic reactions

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National Science Review 2024年第3期11卷 50-51页

作者： Roger Castells-Graells Todd o.Yeates Department of Chemistry and Biochemistry University of California UCLA-DoE Institute for Genomics and Proteomics

Proteins are exceedingly complex molecules though, at their heart, they are essentially linear polymers. Pull at their ends and one obtains an extended backbone. While that is true in most cases, some natural proteins...

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Convergence of neuro-endocrine-immune pathways in the pathophysiology of irritable bowel syndrome

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World Journal of Gastroenterology 2014年第27期20卷 8846-8858页

作者： Maria M Buckley Siobhain M o'Mahony Dervla o'Malley Department of Physiology Western Gateway Building University College Cork Department of Anatomy and Neuroscience and Alimentary Pharmabiotic Centre University College Cork Department of Physiology and Alimentary Pharmabiotic Centre University College Cork

Disordered signalling between the brain and the gut are generally accepted to underlie the functional bowel disorder, irritable bowel syndrome(IBS). However, partly due to the lack of disease-defining biomarkers, understanding the aetiology of this complex and multifactorial disease remains elusive. This common gastrointestinal disorder is characterised by alterations in bowel habit such as diarrhoea and/or constipation, bloating and abdominal pain, and symptom exacerbation has been linked with periods of stress, both psychosocial and infection-related. Indeed, a high level of comorbidity exists between IBS and stress-related mood disorders such as anxiety and depression. Moreover, studies have observed alterations in autonomic output and neuro-endocrine signalling in IBS patients. Accumulating evidence indicates that a maladaptive stress response, probably mediated by the stress hormone, corticotropin-releasing factor contributes to the initiation, persistence and severity of symptom *** risk factors for developing IBS include a positive family history, childhood trauma, dietary factors and prior gastrointestinal infection. An emerging role has been attributed to the importance of immune factors in the pathophysiology of IBS with evidence of altered cytokine profiles and increased levels of mucosal immune cells. These factors have also been shown to have direct effects on neural signalling. This review discusses how pathological changes in neural, immune and endocrine pathways, and communication between these systems, contribute to symptom flares in IBS.

关键词： Stress Corticotropin-releasing factor Proinflammatory cytokines Enteric nervous system Vagus

Two-stage capacity optimization approach of multi-energy system considering its optimal operation

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Energy and AI 2020年第1期1卷 35-63页

作者： X.J.Luo Lukumon o.oyedele olugbenga o.Akinade Anuoluwapo o.Ajayi Big Data Enterprise and Artificial Intelligence Laboratory(Big-DEAL) University of the West of England(UWE)Frenchay CampusBristolUnited Kingdom

With the depletion of fossil fuel and climate change,multi-energy systems have attracted widespread attention in ***-energy systems,fuelled by renewable energy,including solar and biomass energy,are gain-ing increasing adoption in commercial *** of previous capacity design approaches are formulated based upon conventional operating schedules,which result in inappropriate design capacities and ineffective operating schedules of the multi-energy ***,a two-stage capacity optimization approach is pro-posed for the multi-energy system with its optimal operating schedule taken into *** demonstrate the effectiveness of the proposed capacity optimization approach,it is tested on a renewable energy fuelled multi-energy system in a commercial *** primary energy devices of the multi-energy system consist of biomass gasification-based power generation unit,heat recovery unit,heat exchanger,absorption chiller,elec-tric chiller,biomass boiler,building integrated photovoltaic and photovoltaic thermal hybrid solar *** variable efficiency owing to weather condition and part-load operation is also *** algorithm is adopted to determine the optimal design capacity and operating capacity of energy devices for the first-stage and second-stage optimization,*** two optimization stages are interrelated;thus,the optimal design and operation of the multi-energy system can be obtained simultaneously and *** the adoption of the proposed novel capacity optimization approach,there is a 14%reduction of year-round biomass consumption compared to one with the conventional capacity design approach.

关键词： Multi-energy system Renewable energy Biomass Genetic algorithm Capacity design optimization

Social biology of rodents

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Integrative Zoology 2007年第4期2卷 193-204页

作者： Jerry o.WoLFF Department of Biology St.Cloud State UniversitySt.CloudMinnesotaUSA

Herein, I summarize some basic components of rodent social biology. The material in this paper is summarized andcondensed from a recent book “Rodent Societies: An Ecological and Evolutionary Perspective” edited by J. *** and P. W. Sherman (2007). I describe the four basic spacing patterns and illustrate how female territoriality isa function of offspring defense and male mating tactics are a function of female defensibility. The vulnerability ofyoung to infanticide shapes female spacing and mating behavior. Food does not appear to be a defensible resourcefor rodents, except for those species that larder hoard nonperishable items such as seeds. Philopatry and theformation of kin groups result in genetic sub-structuring of the population, which in turn affects effectivepopulation size and genetic diversity. Dispersal is male biased and typically involves emigration from the maternalsite to avoid female relatives and to seek unrelated mates. Scent marking is a major form of communication and isused in reproductive competition and to assess prospective mates, but it is also eavesdropped by predators to locateprey. Females do not appear to alter the sex ratio of litters in response to maternal condition but among arvicolinerodents daughters appear to be favored in spring and sons in autumn. Rodents are relatively monomorphic;however, females tend to be larger than males in the smallest species and smaller in the larger species. Predationrisk results from an interaction among foraging time and vulnerability and in turn affects behavioral and life historycharacteristics.

关键词： chemosignals dispersal infanticide mating systems predation risk rodents social behavior

Fight them or feed them:how the intestinal mucus layer manages the gut microbiota

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Gastroenterology Report 2019年第1期7卷 3-12,I0001页

作者： Bjoern o.Schroeder Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research Department of Molecular and Clinical MedicineInstitute of MedicineBruna Stra°ket 16University of GothenburgSE 41345 GothenburgSweden

The intestinal tract is inhabited by a tremendous number of microorganisms,termed the gut *** microorganisms live in a mutualistic relationship with their host and assist in the degradation of complex *** the gut microbiota is generally considered beneficial,the vast number of microbial cells also form a permanent threat to the ***,the intestinal epithelium is covered with a dense layer of mucus to prevent translocation of the gut microbiota into underlying *** mucus is an organized glycoprotein network with a host-specific glycan *** the mucus layer has long been considered a passive,host-designed barrier,recent studies showed that maturation and function of the mucus layer are strongly influenced by the gut *** return,the glycan repertoire of mucins can select for distinct mucosa-associated bacteria that are able to bind or degrade specific mucin glycans as a nutrient *** the intestinal mucus layer is at the crucial interface between host and microbes,its breakdown leads to gut bacterial encroachment that can eventually cause inflammation and ***,a dysfunctional mucus layer has been observed in colitis in mice and ***,the increased consumption of a low-fiber Western-style diet in our modern society has recently been demonstrated to cause bacteria-mediated defects of the intestinal mucus ***,I will review current knowledge on the interaction between gut bacteria and the intestinal mucus layer in health and *** the molecular details of this host–microbe interaction may contribute to the development of novel treatment options for diseases involving a dysfunctional mucus layer,such as ulcerative colitis.

关键词： Dietary fiber gut microbiota host-microbe interaction inflammatory bowel disease mucus mucin mucosal barrier metabolic disease probiotics ulcerative colitis

Biliary cysts:Etiology,diagnosis and management

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World Journal of Gastroenterology 2012年第35期18卷 4801-4810页

作者： Beata Jabońska Department of Digestive Tract Surgery University Hospital of the Medical University of Silesia

Biliary cysts(BC) are rare dilatations of different parts of a biliary *** account for approximately 1% of all benign biliary *** occur the most frequently in Asian and female *** are an important problem for pediatricians,gastroenterologists,radiologists and *** presentation and management depend on the BC *** is the most serious and dangerous BC *** other complications associated with BC involve cholelithiasis and hepatolithiasis,cholangitis,acute and chronic pancreatitis,portal hypertension,liver fibrosis and secondary liver cirrhosis and spontaneous cyst *** BC classifications have been described in the *** classification dividing BC into five types is the most useful in clinical *** early diagnosis and proper treatment are very important,because BC are associated with a risk of carcinogenesis.A malignancy risk increases with the *** investigations(ultrasonography,computed tomography,endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography) play an important role in BC ***,prenatal diagnosis using ultrasonography is *** allows to differentiate biliary disorders in fetals and to perform the early surgical treatment that improves *** most patients,total cyst excision with Roux-Y hepaticojejunostomy is the treatment of *** treat-ment of BC is associated with high success rate and low morbidity and *** early treatment is associated with a lower number of *** following BC surgery require permanent and careful postoperative observation using laboratory and imaging investigations because of possibility of biliary anastomosis stricture and biliary cancer in tissue remnant.

关键词： Biliary cysts Biliary drainage Hepaticojeju-nostomy

Anaerobic digestion of cyanobacteria and chlorella to produce methane for biofuel

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International Journal of Agricultural and Biological Engineering 2012年第3期5卷 68-74页

作者： Abiodun o.Jegede Centre for Energy Research and Development Obafemi Awolowo UniversityIle-IfeOsunNigeria

The methane potentials of cyanobacteria and chlorella have been investigated in eight different lab scale reactors at 25℃for three-day Hydraulic Retention Time(HRT).Autoclavation pre-treatment was applied to the cyanobacteria to aid digestion,while the Chlorella was obtained and digested in powdery *** organic loading rates were 1g VS,2 g VS,3 g VS,4 g VS,5 g VS,6 g VS,7 g VS,8 g VS and 9 g *** production rates increased with increasing loading rates and started declining at loading rate higher than 7 g VS,while the HRT was kept *** highest methane production rates for cyanobacteria and chlorella were(78±25)mL/(L·d)and(100±25)mL/(L·d),respectively,at loading rate of 7 g *** instability occurred at loading rates of 8 g VS and 9 g VS with higher accumulation of methane *** compositions of both feeds were close and the methane production potentials of both biomasses were also close and followed the same trend.

关键词： anaerobic digestion biofuel carbon dioxide(Co2) Hydraulic Retention Time(HRT) methane(CH4) chemical oxygen demand(CoD) volatile fatty acids(VFAs)

Indentation Size Effect and Microhardness Study of β-Sn Single Crystals

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Chinese Physics Letters 2005年第12期22卷 3137-3140页

作者： o. SAHIN o. UZUN U. KoLEMEN B. DUZGUN N. UCAR Department of Physics Art and Science Faculty Suleyman Demirel University Isparta Turkey Department of Physics Art and Science Faculty Gaziosmanpasa University Tokat Turkey Department of Physics K. K. Education Faculty Ataturk-University Erzurum Turkey

The load dependence of apparent microhardness of β-Sn single crystals having different growth directions is investigated. The measurements are performed on （110） planes of these crystals in the load range from 10 to 50 mN. It is found that the degree of the microhardness anisotropy decreases for higher indentation test loads. The examined materials exhibit the behaviour of indentation size effect （ISE）, i.e., the apparent hardness increases with decreasing indentation load. Neither Meyer＇s law nor the proportional specimen resistance （PSR） model can fully explain the nonlinear variation of microhardness with load. Instead, preference is given to modified the PSR model based on the consideration of the effect of machining-induced residually stressed surface on the hardness measurement.

关键词： Microhardness