课程文献中心 更多>>

关键词： Cartilage fibre orientation   Finite element analysis   Cartilage stress distribution   Split lines  

摘要： This study presents an evaluation of the role that cartilage fibre 'split line' orientation plays in informing femoral cartilage stress patterns. A two-stage model is presented consisting of a whole knee joint coupled to a tissue-level cartilage model for computational efficiency. The whole joint model may be easily customised to any MRI or CT geometry using free-form deformation. Three 'split line' patterns (medial-lateral, anterior-posterior and random) were implemented in a finite element model with constitutive properties referring to this 'split line' orientation as a finite element fibre field. The medial-lateral orientation was similar to anatomy and was derived from imaging studies. Model predictions showed that 'split lines' are formed along the line of maximum principal strains and may have a biomechanical role of protecting the cartilage by limiting the cartilage deformation to the area of higher cartilage thickness.

关键词： Polycyclic aromatic hydrocarbons   Benzo[a]pyrene toxic equivalents   Gulf menhaden   Northern Gulf of Mexico   Oil spill  

摘要： Approximately 4.9 million barrels of crude oil and gas were released into the Gulf of Mexico (GoM) from April to July 2010 during the Deepwater Horizon (DWH) spill. This resulted in the possible contamination of marine organisms with polycyclic aromatic hydrocarbons (PAHs), USEPA identified constituents of concern. To determine the impact of the DWH oil spill, Gulf menhaden (Brevoortia patronus), a commercially harvested and significant trophic grazing species, was sampled from two Louisiana coastal regions between the years 2011-2013. Tissue extraction and GC/MS analysis demonstrated measurable concentrations of PAH within menhaden. Analysis yielded total PAHs, carcinogenic equivalents (BaP-TEQ), and mutagenic equivalents (BaP-MEQ) which provided an initial toxic potential assessment of this GoM Fishery. Gulf menhaden contained less total PAH concentrations in 2012 and significantly less in 2013 as compared to 2011 (p < 0.05) ranging from 7 ug/g tissue dry weight to 3 ng/g tissue dry weight. Carcinogenic and mutagenic PAHs were also significantly reduced (p < 0.05) over the three year period. The reduction of total PAH concentrations and the reduction of BaP-TEQs and MEQs between 2011 and 2013 indicates a diminished input of new source PAHs along with a reduction of carcinogenic and mutagenic PAHs in menhaden populations. The use of Gulf menhaden was successful in determining the acute toxic potential of PAHs contaminating the GoM in the years directly following the DWH spill event. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： PSCA   DCC   polymorphism   cancer   meta-analysis  

摘要： Multiple studies have investigated the association of gene variant of Deleted in colorectal carcinoma (DCC) and Prostate Stem cell antigen (PSCA) with various cancer susceptibility; however, the results are discrepant. Since SNPs are emerging as promising biomarker of cancer susceptibility, here, we aimed to execute a meta-analysis of DCC (rs714 A > G) and PSCA (rs2294008 C > T, rs2976392 G > A) polymorphism to demonstrate the more accurate strength of these associations. We followed a rigorous inclusion/exclusion criteria and calculated the pooled odds ratios (ORs) and 95% confidence intervals (CIs). Overall, the pooled analysis showed that the DCC rs714 conferred increased risk of cancer only in Asians (AA vs. GG: OR = 1.86, p ≤ 0.0001; AG vs. GG: OR = 1.43, p = 0.005; GA + AA vs. GG: OR = 1.66, p ≤ 0.0001; AA vs. GG + GA; OR = 1.52, p ≤ 0.004, A vs. G allele: OR = 1.41, p ≤ 0.0001). PSCA rs2294008 was associated with increased overall cancer risk (TT vs. CC: OR = 1.28, p = 0.002; CT vs. CC: OR = 1.21, p ≤ 0.0001; CT + TT vs. CC: OR = 1.24, p ≤ 0.0001; TT vs. CC + CT; OR = 1.17, p ≤ 0.005, T vs. C allele: OR = 1.16, p ≤ 0.0001); however, in stratified analysis this association was limited only to gastric and bladder cancer and the strength was more prominent in Asians. In contrast, the PSCA rs2976392 SNP did not modulate the cancer risk. Therefore, we concluded that rs714 and rs2294008 polymorphism may represent a potential genetic biomarker for cancer risk in Asians and gastric as well as bladder cancer, respectively. However, since our study is limited to Asians and cancer types, further larger studies involving other cancers and/or population, gene-environment interactions and the mechanism of DCC and PSCA gene deregulation are desired to define the role of genotype with overall cancer risk.

关键词： 地铁   房价   南昌  

摘要： 地铁作为当前城市交通最方便快捷的一个途径,已成为众多城市交通规划中的首选。地铁对城市的影响,不仅限于交通的通达便利度,在众多影响中,本文以南昌一号线为例,通过站点附近楼盘二手房房价及该区域均价做对比,发现地铁对房价的正面影响较大,并对其后续地铁建设及周围投资,简单做出相对应的建议。

关键词： Quantum wells   Optical properties   III-V semiconductors   Focused ion beam technology   Semiconductor growth  

摘要： The optical properties of m-plane InGaN/GaN quantum wells grown on microwire sidewalls were investigated carrying out a correlative scanning transmission electron microscopy (STEM), atom probe tomography (APT), and micro-photoluminescence study applied on single nanoscale field-emission tips obtained by a focused ion beam annular milling. Instead of assuming simple rectangular composition profiles, yielding misleading predictions for the optical transition energies, we can thus take into account actual compositional distributions and the presence of stacking faults (SFs). SFs were shown to be responsible for a lowering of the recombination energies of the order of 0.1 eV with respect to those expected for defect-free quantum wells (QWs). Such energy reduction allows establishing a good correspondence between the transition energies observed by optical spectroscopy and those calculated on the basis of the QWs In measured composition and distribution assessed by STEM structural analysis and APT chemical mapping. (C) 2016 AIP Publishing LLC.

关键词： RESEARCH   BP Deepwater Horizon Explosion & Oil Spill, 2010   Salt marshes   Littorinidae   Nutrient cycles   Food chains (Ecology)  

摘要： Deepwater Horizon was the largest marine oil spill in U.S. waters, oiling large expanses of coastal wetland shorelines. We compared marsh periwinkle (Littoraria irrorata) density and shell length at salt marsh sites with heavy oiling to reference conditions similar to 16 months after oiling. We also compared periwinkle density and size among oiled sites with and without shoreline cleanup treatments. Densities of periwinkles were reduced by 80-90% at the oiled marsh edge and by 50% in the oiled marsh interior (similar to 9 m inland) compared to reference, with greatest numerical losses of periwinkles in the marsh interior, where densities were naturally higher. Shoreline cleanup further reduced adult snail density as well as snail size. Based on the size of adult periwinkles observed coupled with age and growth information, population recovery is projected to take several years once oiling and habitat conditions in affected areas are suitable to support normal periwinkle life-history functions. Where heavily oiled marshes have experienced accelerated erosion as a result of the spill, these habitat impacts would represent additional losses of periwinkles. Losses of marsh periwinkles would likely affect other ecosystem processes and attributes, including organic matter and nutrient cycling, marsh-estuarine food chains, and multiple species that prey on periwinkles.

摘要： The greenhead horse fly, Tabanus nigrovittatus Macquart, is frequently found in coastal marshes of the Eastern United States. The greenhead horse fly larvae are top predators in the marsh and thus vulnerable to changes in the environment, and the adults potentially are attracted to polarized surfaces like oil. Therefore, horse fly populations could serve as bioindicators of marsh health and toxic effects of oil intrusion. In this study, we describe the impact of the April 2010 Deep Water Horizon oil spill in the Gulf of Mexico on tabanid population abundance and genetics as well as mating structure. Horse fly populations were sampled biweekly from oiled and unaffected locations immediately after the oil spill in June 2010 until October 2011. Horse fly abundance estimates showed severe crashes of tabanid populations in oiled areas. Microsatellite genotyping of six pristine and seven oiled populations at ten polymorphic loci detected genetic bottlenecks in six of the oiled populations in association with fewer breeding parents, reduced effective population size, lower number of family clusters and fewer migrants among populations. This is the first study assessing the impact of oil contamination at the level of a top arthropod predator of the invertebrate community in salt marshes.

关键词： 50Hz   digital power line filter   glaucoma   multifocal ERG   notch filter  

摘要： Purpose: To assess the effect of a 50Hz power line digital filter on the response to a 2-global-flash multifocal electroretinogram (mfERG) in primary open angle glaucoma (POAG) compared to control. Materials and methods: A 2-global-flash mfERG (VERIS) was recorded (23 control, 34 POAG). Eight recordings were noise contaminated: 4 control, 4 POAG. Response averages from the central 10 degrees and 7 surrounding groups were analyzed with and without a 50Hz digital filter for the following mfERG response epochs: direct component (15-45ms), 1st (45-75ms) and 2nd (75-105ms) induced components. Results: A digital 50Hz filter had little effect on uncontaminated with noise waveforms but, in noisy recordings, changed the waveform dramatically to resemble uncontaminated waveforms. In controls' 50Hz-filtered uncontaminated with noise mfERGs differed significantly from unfiltered responses in induced components. Uncontaminated with noise recordings from glaucoma patients did not differ with or without the notch filter (p>0.1 for all three epochs of mfERG). The mfERG response in the central 10 degrees in glaucoma patients differed significantly from controls, whether the notch filter was used or not (p<0.001). Conclusions: A 50Hz notch filter allows grossly contaminated waveforms to be analyzed in a meaningful manner. With a 50Hz filter, glaucoma patients still differed significantly from normal.

关键词： 昆明地铁二号线   开发利益   影响范围  

摘要： 城市轨道交通在城市公共交通中发挥着越来越大的作用。通过运用模型从轨道交通沿线区域可达性的角度分析昆明市地铁二号线各站点(环城南路站—北部汽车站)开发利益的影响范围,研究结果表明:地铁二号线会影响周围房地产价格,并且各站点影响半径是不一样的,其与距离城市中心车站的距离呈反比例关系,这些站点的平均影响范围为0.650km。

关键词： 中国股市   “五一”长假   中国资本市场   改革试点   运行轨迹   A股市场   股权分置   上市公司  

摘要： 上期的文章笔者简单概述了五条线的形成以及未来预期。本文笔者详细来解读1号线和2号线的运行轨迹。10年前的2005年6月前后，中国A股市场发生了几个重大事件，与笔者的1号线起点有着密切的关系。2005年5月股改试点正式启动，“五一”长假前夕，证监会一纸《关于上市公司股权分置改革试点有关问题的通知》，拉开了中国资本市场一场深刻革命的序幕。