检索结果-南通市图书馆

The neuroimaging of neurodegenerative and vascular disease in the secondary prevention of cognitive decline

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2021年第8期16卷 1490-1499页

作者： Morgan j.Schaeffer Leona chan philip A.Barber Department of Clinical Neurosciences University of CalgaryCalgaryABCanada

Structural brain changes indicative of dementia occur up to 20 years before the onset of clinical symptoms. Efforts to modify the disease process after the onset of cognitive symptoms have been unsuccessful in recent years. Thus, future trials must begin during the preclinical phases of the disease before symptom onset. Age related cognitive decline is often the result of two coexisting brain pathologies: Alzheimer's disease(amyloid, tau, and neurodegeneration) and vascular disease. This review article highlights some of the common neuroimaging techniques used to visualize the accumulation of neurodegenerative and vascular pathologies during the preclinical stages of dementia such as structural magnetic resonance imaging, positron emission tomography, and white matter hyperintensities. We also describe some emerging neuroimaging techniques such as arterial spin labeling, diffusion tensor imaging, and quantitative susceptibility mapping. Recent literature suggests that structural imaging may be the most sensitive and cost-effective marker to detect cognitive decline, while molecular positron emission tomography is primarily useful for detecting disease specific pathology later in the disease process. Currently, the presence of vascular disease on magnetic resonance imaging provides a potential target for optimizing vascular risk reduction strategies, and the presence of vascular disease may be useful when combined with molecular and metabolic markers of neurodegeneration for identifying the risk of cognitive impairment.

关键词： amyloid arterial spin labeling cognitive decline dementia imaging magnetic resonance imaging positron emission tomography quantitative susceptibility mapping tau vascular disease white matter hyperintensities

Bone targeted therapies for the prevention of skeletal morbidity in men with prostate cancer

在线全文

学校读者我要写书评

暂无评论

Asian journal of Andrology 2014年第3期16卷 341-347页

作者： philip j Saylor Division of Hematology-Oncology Massachusetts General Hospital Cancer Center Boston Massachusetts USA.

Men with prostate cancer suffer substantially from bone-related complications. Androgen deprivation therapy itself is a cause of loss of bone mineral density and is associated with an increased incidence of osteoporotic fractures. In advanced disease, bone is by far the most common site of metastasis. Complications of bone metastases prominently include pain and the potential for skeletal events such as spinal cord compression and pathologic fractures. Elevated osteoclast activity is an important aspect of the pathophysiology of both treatment-related osteoporosis and skeletal complications due to metastases. The osteoclast is therefore a therapeutic target. Denosumab is a fully human monoclonal antibody to receptor activator of nuclear factor-K-B ligand that was designed to potently inhibit osteoclast activity and is the central focus of this review. Bisphosphonates, radiopharmaceuticals and systemically-active hormonal agents such as abiraterone acetate and enzalutamide have each been shown to improve skeletal morbidity in specific clinical situations. Denosumab is the only agent that has been shown to prevent osteoporotic fractures in men receiving androgen deprivation therapy and at elevated risk for fracture. It has also demonstrated superiority to the potent bisphosphonate zoledronic acid for the prevention of skeletal-related events in men with castration-resistant prostate cancer metastatic to bone. Efficacy and toxicity data will be discussed.

关键词： denosumab osteoporosis osteopenia osteoclast RANK (receptor activator of nuclear factor-kappa B) skeletal-relatedevents

PREPARATION OF ASYMMETRIC POLYETHERKETONE FLAT AND HOLLOW FIBER MEMBRANES FOR GAS SEPARATION USING ACETIC ACID BASED COAGULANTS

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

Chinese journal of Polymer Science 2008年第3期26卷 263-273页

作者：杨继萍 philip j.Brown School of Material Science and Engineering Beihang UniversityBeijing 100083China School of Materials Science and Engineering Clemson UniversitySC29634USA

Membranes for gas separation have developed significantly in the last twenty years,however,there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas *** study examines the fundamental properties of polyetherketone (PEK,a thermally stable and chemically resistant polymer) membranes prepared using concentrated sulphuric acid (98% H_2SO_4) as the ***-solvents used in the work included acetic acid,ethanol,methanol,glycerol,and water....

关键词： Polyetherketones Membranes Gas permeation Internal coagulant effect Morphology

Sediment generation and soil mound denudation in areas of high-density tree throw along a river valley in the jura Mountains, Switzerland

在线全文

学校读者我要写书评

暂无评论

journal of Mountain Science 2021年第2期18卷 377-391页

作者： philip GREENWOOD jan BAUER Nikolaus j KUHN Physical Geography&Environmental change Research Group Department of Environmental SciencesUniversity of BaselKlingelbergstrasse 27Basel-4056Switzerland

A preliminary field-based investigation was undertaken in a small(<10 km^(2))river valley located in the mountainous jura region of northwest *** aims of the work were to assess sediment generation and annual sediment... 详细信息

A preliminary field-based investigation was undertaken in a small(jura region of northwest *** aims of the work were to assess sediment generation and annual sediment transport rates by tree throw on forested hillslopes,and to document surface hydrology characteristics on four fresh soil mounds associated with recent tree throws over a 24-day monitoring *** the soil mounds,average sediment recovery ranged from 7.7-28.2 g(dry weight),equivalent to a suspended sediment concentration of 145.2-327.8 g L^(-1),and runoff coefficients ranged from 1.0%-4.2%.Based on a soil bulk density value of 1,044 kg m^(-3),upslope runoff generation areas were denuded by an average 0.14 mm by the end of the 24-day monitoring period,representing an erosion rate equivalent to 2.1 mm yr^(-1).A ca.50 cm high soil mound could therefore feasibly persist for around 200-250 *** tree throw work,the dimensions of 215 individual tree throws were measured and their locations mapped in 12 separate locations along the river valley representing a cumulative area equivalent to 5.3 ha(***,43 per ha).Tree throws generated a total of 20.1 m^(3) of fine-sediment(jority of tree throws,but instead,could be associated with root *** the high density of tree throws and their relative maturity(average age 41 years),we hypothesise that once tr

关键词： Tree throw Hillslope processes Sediment generation mechanism Sediment transport rate Soil mound Ibach river valley

Glucose transporter 4 can be inserted in the membrane without exposing its catalytic site for photolabeling from the medium

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2007年第2期50卷 147-154页

作者： Manabu ISHIKI philip j BILAN Programme in Cell Biology Hospital for Sick Children Toronto Canada M5G 1×8

Insulin stimulates the production of PI(3,4,5)P3 in muscle cells, and this is required to stimulate GLUT4 fusion with the plasma membrane. Introduction of exogenous PI(3,4,5)P3 to muscle cells recapitulates insulin's effects on GLUT4 fusion with the plasma membrane, but not glucose uptake. This study aims to explore the mechanism behind this difference. In L6-GLUT4myc muscle cells, the availability of the GLUT4 intracellular C-terminus and extracellular myc epitopes for immunoreactivity on plasma membrane lawns was detected with the corresponding antibody. The availability of the active site of GLUT4 from extracellular medium was assessed by affinity photolabeling with the cell impermeant compound Bio-LC-ATB-BMPA. 100nmol/L insulin and 10μmol/L PI(3,4,5)P3 caused myc signal gain on the plasma membrane lawns by 1.64-fold and 1.58-fold over basal, respectively. Insulin, but not PI(3,4,5)P3, increased photolabeling of GLUT4 and immunolabeling with C-terminus antibody by 2.47-fold and 2.04-fold over basal, respectively. Upon insulin stimulation, the C-terminus signal gain was greater than myc signal gain (2.04-fold vs. 1.64-fold over basal, respectively) in plasma membrane lawns. These results indicate that (i) PI(3,4,5)P3 does not make the active site of GLUT4 available from the extracellular surface despite causing GLUT4 fusion with the plasma membrane; (ii) the availability of the active site of GLUT4 from the extracellular medium and availability of the C-terminus from the cytosolic site are correlated; (iii) in addition to stimulating GLUT4 translocation, insulin stimulation displaces a protein which masks the GLUT4 C-terminus. We propose that a protein which masks the C-terminus also prevents the active site from being available for photolabelling and possibly glucose uptake after treatment with PI(3,4,5)P3.

关键词： glucose transport 4 (GLUT4) insulin phosphatidylinositol 3 4 5-trisphosphate (PI(3 4 5)P3) photolabel

Insulin sensitivity and inhibition by forskolin,dipyridamole and pentobarbital of glucose transport in three L6 muscle cell lines

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2007年第6期50卷 739-747页

作者： philip j BILAN Michiko HAYASHI Programme in Cell Biology Hospital for Sick Children Toronto Canada M5G 1X8

L6 skeletal muscle myoblasts stably overexpressing glucose transporter GLUT1 or GLUT4 with exofa- cial myc-epitope tags were characterized for their response to insulin. In clonally selected cultures, 2-deoxyglucose uptake into L6-GLUT1myc myoblasts and myotubes was linear within the time of study. In L6-GLUT1myc and L6-GLUT4myc myoblasts, 100 nmol/L insulin treatment increased the GLUT1 content of the plasma membrane by 1.58±0.01 fold and the GLUT4 content 1.96±0.11 fold, as well as the 2-deoxyglucose uptake 1.53±0.09 and 1.86±0.17 fold respectively, all by a wortmannin-inhibitable manner. The phosphorylation of Akt in these two cell lines was increased by insulin. L6-GLUT1myc myoblasts showed a dose-dependent stimulation of glucose uptake by insulin, with unaltered sensitiv- ity and maximal responsiveness compared with wild type cells. By contrast, the improved insulin re- sponsiveness and sensitivity of glucose uptake were observed in L6-GLUT4myc myoblasts. Earlier studies indicated that forskolin might affect insulin-stimulated GLUT4 translocation. A 65% decrease of insulin-stimulated 2-deoxyglucose uptake in GLUT4myc cells was not due to an effect on GLUT4 mobi- lization to the plasma membrane, but instead on direct inhibition of GLUT4. Forskolin and dipyridamole are more potent inhibitors of GLUT4 than GLUT1. Alternatively, pentobarbital inhibits GLUT1 more than GLUT4. The use of these inhibitors confirmed that the overexpressed GLUT1 or GLUT4 are the major functional glucose transporters in unstimulated and insulin-stimulated L6 myoblasts. Therefore, L6-GLUT1myc and L6-GLUT4myc cells provide a platform to screen compounds that may have differ- ential effects on GLUT isoform activity or may influence GLUT isoform mobilization to the cell surface of muscle cells.

关键词： L6 muscle cells, glucose transporter (GLUT), insulin, 2-deoxyglucose uptake

Slope failure simulations with MPM

在线全文

学校读者我要写书评

暂无评论

journal of Hydrodynamics 2017年第3期29卷 445-451页

作者： philip j.Vardon Bin Wang Michael A.Hicks Geo-Engineering Section Faculty of Civil Engineering and GeosciencesDelft University of Technology State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences

The simulation of slope failures,including both failure initiation and development,has been modelled using the material point method（MPM）.Numerical case studies involving various slope angles,heterogeneity and rainfall infiltration are *** is demonstrated that,by utilising a constitutive model which encompasses,in a simplified manner,both pre-and post-failure behaviour,the material point method is able to simulate commonly observed failure *** is a step towards being able to better quantify slope failure consequence and risk.

关键词： Heterogeneity material point method(MPM) rainfall-induced slope failure strain softening

Dryland agriculture and rangeland restoration priorities in Afghanistan

在线全文

学校读者我要写书评

暂无评论

journal of Arid Land 2015年第3期7卷 391-402页

作者： Michael j jACOBS Catherine A SCHLOEDER philip D TANIMOTO Texas Agri Life Research Department of Ecosystem Science & Management2138TAMUCollege StationTX 77843-2138USA Oikos Services LLCFortineMT 59918USA Conservation Imaging Inc.AuburndaleMassachusetts 02466USA

Afghanistan is threatened by rangeland degradation.A quantitative visual analysis of Google Earth Imagery was used to systematically locate,characterize and quantify the current extent of rangelands in Afghanistan degraded as a consequence of dryland *** data were used in conjunction with dryland agriculture locations to establish a climate envelope comprised by temperature and mean annual precipitation to create a geographical mask known to contain dryland *** this mask we created a grid of 100 km2 cells that we analyzed individually to access dryland agriculture *** limits to sustainable dryland agriculture and areas of high restoration priority were also assessed as was the distribution of rain-fed agriculture with respect to the location of traditional migration routes for extensive livestock *** extents of agriculture in Afghanistan,at both upper and lower elevations,correlated most closely with mean annual temperature（MAT） at the upper elevation limits,and with mean annual precipitation（MAP） at the lower elevation *** total,dryland agriculture comprised 38,980 km2 of former native *** was highest in the northwestern,northern and northeastern provinces of Herat,Badghis,Faryab,jawzjan,Sar-e-Pul,Samangan,Balkh,Baghlan,Kunduz,Takhar and Badakhshan,with the highest percentage of conversion occurring in *** MAP value of 〈400 mm is perceived by farmers as the current climatic limit to sustainable dryland agriculture across the northern regions of the *** this MAP value,approximately 27,677 km2 of converted rangeland met the need for restoration *** projections indicate that Afghanistan will become warmer and drier in the coming *** consequence of this trend is that the MAP threshold of 〈400 mm to sustainable dryland agriculture will become obsolete in the coming *** of currently converted rangelands is needed to restore critical grazing area

关键词： degradation climatic trends extensive livestock production dryland agriculture rangeland restoration

Study on Characteristics of Co-firing Ammonia/Methane Fuels under Oxygen Enriched Combustion Conditions

在线全文

学校读者我要写书评

暂无评论

journal of Thermal Science 2018年第3期27卷 270-276页

作者： XIAO Hua WANG Zhaolin VALERA-MEDINA Agustin BOWEN philip j School of Engineering Cardiff University College of Energy Xiamen University

Having a background of utilising ammonia as an alternative fuel for power generation, exploring the feasibility of co-firing ammonia with methane is proposed to use ammonia to substitute conventional natural gas. However, improvement of the combustion of such fuels can be achieved using conditions that enable an increase of oxygenation, thus fomenting the combustion process of a slower reactive molecule as ammonia. Therefore, the present study looks at oxygen enriched combustion technologies, a proposed concept to improve the performance of ammonia/methane combustion. To investigate the characteristics of ammonia/methane combustion under oxygen enriched conditions, adiabatic burning velocity and burner stabilized laminar flame emissions were studied. Simulation results show that the oxygen enriched method can help to significantly enhance the propagation of ammonia/methane combustion without changing the emission level, which would be quite promising for the design of systems using this fuel for practical applications. Furthermore, to produce low computational-cost flame chemistry for detailed numerical analyses for future combustion studies, three reduced combustion mechanisms of the well-known Konnov's mechanism were compared in ammonia/methane flame simulations under practical gas turbine combustor conditions. Results show that the reduced reaction mechanisms can provide good results for further analyses of oxygen enriched combustion of ammonia/methane. The results obtained in this study also allow gas turbine designers and modellers to choose the most suitable mechanism for further combustion studies and development.

关键词： Ammonia/Methane Oxygen-enriched Combustion Reduced Mechanism Gas Turbine