检索结果-南通市图书馆

具有不同对称轴的两种方位各向异性介质中的横波双折射

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

具有不同对称轴的两种方位各向异性介质中的横波双折射

美国勘探地球物理学家学会第62届年会

作者： Rick Slack Dan Ebrom j．A．mcdonald Robert A．Tatham 张淑敏 CogniSeis Development Univ．of Houston Texaco Inc

我们用数值模型研究与物理模型实验研究了第二个方位各向异性层对上覆地层各向异性特征的影响。人们认为,近地表风化层是引起通过下伏地层传播脉冲畸变的强各向异性层,因此,任何通过近表层的横波信号都会附有这层的各向异性响应。有能...

我们用数值模型研究与物理模型实验研究了第二个方位各向异性层对上覆地层各向异性特征的影响。人们认为,近地表风化层是引起通过下伏地层传播脉冲畸变的强各向异性层,因此,任何通过近表层的横波信号都会附有这层的各向异性响应。有能使以前的分裂横波通过又不损失下伏各向异性地层信息的临界地层厚度吗?我们发现,引起时间延迟≥τ／4的(τ=子波主频的周期)方位各向异性的地层厚度使上覆地层的各向异性特征畸变。通过测量快和慢波速度之间的差值并除以快波速度就可使各向异性量化。所得分数代表那一地层各向异性的程度。假定速度的各向异性为5％,主频为40赫,为使上面地层的各向异性特征畸变,则要求近地表层的厚度为125米。当各向异性的程度趋于25％时,风化层的厚度仅需30米或以下,便会使它本身的各向异性响应给以前的地层特征带来影响。

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

老年人急性心肌梗塞的表现

国际老年医学杂志 1985年第3期 107-109页

作者： mcdonald j B 林祥春

非典型性和无痛性心肌梗塞较常见于老年人。1912年Herrick报道无痛性急性心肌梗塞以来,有关无痛性心肌梗塞的文献越来越多。通常认为,急性心肌梗塞(AMI)的经典表现为心前区挤压性疼痛。疼痛可放射到颚、一侧或双侧上肢,也可放射到上腹... 详细信息

非典型性和无痛性心肌梗塞较常见于老年人。1912年Herrick报道无痛性急性心肌梗塞以来,有关无痛性心肌梗塞的文献越来越多。通常认为,急性心肌梗塞(AMI)的经典表现为心前区挤压性疼痛。疼痛可放射到颚、一侧或双侧上肢,也可放射到上腹部。文献所报道的无痛性急性心肌梗塞的发病率差异甚大(4～60％)。神经病、精神错乱、昏迷和言语困难的患者由于不能提供可靠的病史资料也常被列入无痛性AMI组。有人根据98例AMI患者所进行的死后研究

关键词：无痛性心肌梗塞患者诊断标准 WHO 病人急性心肌梗塞 AMI 老年人

Chronic exposure to excess iron promotes EMT and cancer via p53 loss in pancreatic cancer

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Asian journal of Pharmaceutical Sciences 2020年第2期15卷 237-251页

作者： Yangzom D.Bhutia jiro Ogura Paul j.Grippo Carolina Torres Toshihiro Sato mitchell Wachtel Sabarish Ramachandran Ellappan Babu Sathish Sivaprakasam Devaraja Rajasekaran Bradley Schniers Nhu On Logan Smoot Muthusamy Thangaraju jaya P.Gnana-Prakasam Vadivel Ganapathy Department of Cell Biology and Biochemistry Texas Tech University Health Sciences CenterLubbockTX 79430USA Department of Pharmaceutical Sciences Tohoku University Hospital1-1 Seiryo-machiAoba-kuSendaiMiyagi 980-8574Japan Department of Medicine University of Illinois at ChicagoChicagoIL 60607USA Department of Surgical Pathology Texas Tech University Health Sciences CenterLubbockTX 79430USA Department of Biological Sciences Texas Tech UniversityLubbockTX 79410USA Department of Chemistry and Biochemistry Texas Tech UniversityLubbockTX 79410USA Department of Biochemistry and Molecular Biology Augusta UniversityAugustaGA 30912USA Department of Ophthalmology St.Louis UniversitySt.LouisMO 63104USA

Based on the evidence that hemochromatosis, an iron-overload disease, drives hepatocellular carcinoma, we hypothesized that chronic exposure to excess iron, either due to genetic or environmental causes, predisposes an individual to cancer. Using pancreatic cancer as our primary focus, we employed cell culture studies to interrogate the connection between excess iron and cancer, and combined in vitro and in vivo studies to explore the connection further. Ferric ammonium citrate was used as an exogenous iron source. Chronic exposure to excess iron induced epithelial-mesenchymal transition(EMT) in normal and cancer cell lines, loss of p53, and suppression of p53 transcriptional activity evidenced from decreased expression of p53 target genes(p21, cyclin D1, Bax, SLC7A11). To further extrapolate our cell culture data, we generated EL-KrasG12D( EL-Kras) mouse(pancreatic neoplastic mouse model) expressing Hfe+/+ and Hfe-/- genetic background. p53 target gene expression decreased in EL-Kras/Hfe-/- mouse pancreas compared to EL-Kras/Hfe+/+ mouse pancreas. Interestingly, the incidence of acinar-to-ductal metaplasia and cystic pancreatic neoplasms(CPN) decreased in EL-Kras/Hfe-/- mice, but the CPNs that did develop were larger in these mice than in EL-Kras/Hfe+/+ mice. In conclusion, these in vitro and in vivo studies support a potential role for chronic exposure to excess iron as a promoter of more aggressive disease via p53 loss and SLC7A11 upregulation within pancreatic epithelial cells.

关键词： SLC7A11 p53 Iron Heme Epithelial-mesenchymal transition

维普期刊数据库

Marsh persistence under sea-level rise is controlled by multiple,geologically variable stressors

在线全文

学校读者我要写书评

暂无评论

Ecosystem Health and Sustainability 2017年第10期3卷 22-38页

作者： M.mitchell j.Herman D.M.Bilkovic C.Hershner Virginia Institute of Marine Science College of William&MaryGloucester PointVAUSA

Introduction:Marshes contribute to habitat and water quality in estuaries and coastal *** importance to continued ecosystem functioning has led to concerns about their ***:Concurrent with sea-level rise,marshes are eroding and appear to be disappearing through ponding in their interior;in addition,in many places,they are being replaced with shoreline stabilization *** examined the changes in marsh extent over the past 40 years within a subestuary of Chesapeake Bay,the largest estuary in the United States,to better understand the effects of sea-level rise and human pressure on marsh ***:Approximately 30 years ago,an inventory of York River estuary marshes documented the historic extent of *** were resurveyed in 2010 to examine shifts in tidal marsh extent and *** change varied spatially along the estuary,with watershed changes between a 32%loss and an 11%gain in marsh *** of marsh was apparent in high energy sections of the estuary while there was marsh gain in the upper/riverine section of the estuary and where forested hummocks on marsh islands have become *** showed little change in the small tributary creeks,except in the creeks dominated by fringing marshes and high shoreline ***:Differential resilience to sea-level rise and spatial variations in erosion,sediment supply,and human development have resulted in spatially variable changes in specific marsh extents and are predicted to lead to a redistribution of marshes along the estuarine gradient,with consequences for their unique communities.

关键词： Chesapeake Bay climate change coastal resilience marsh change salt marsh sea-level rise tidal wetlands

Controlling and Evaluating the Structure and Morphology of Polymers on Multiple Scales

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

journal of Materials Science and Chemical Engineering 2015年第12期3卷 48-60页

作者： Geoffrey R. mitchell Ana Tojeira Thomas Gkourmpis james j. Holt Peter Harris Marilena Pezzuto Centre for Rapid and Sustainable Product Development Institute Polytechnic of Leiria Marinha Grande Portugal Innovation & Technology Borealis AB Stenungsund Sweden Department of Physics University of Reading Whiteknghts Reading UK Centre for Advanced Microscopy University of Reading Whiteknights Reading UK CNR-Istituto di Chimica e Tecnologia dei Polimeri Pozzuoli Italy

Crystalline polymers spontaneously form hierarchical structures although the precise manner in which these scales of structure are interconnected especially terms of the formation and evolution of the complete structure remains unclear. We have set out to control these scales of structure by introducing additional components which self-assemble in to nano-scale units which then direct the crystallisation of the polymer matrix. In other words, we first assemble a low concentration top-level structure which is designed to template or direct the sub-sequent crystallisation of the matrix polymer. This top level structure takes on the role of controlling the structure. We have set out to both establish the design principles of such structures and to develop experimental procedures which allow us to follow the formation of such complex hierarchical polymer structures. In particular we focus of the relationships between these different levels of structure and time sequence of events required for the structure to evolve in the targeted manner. In this programme, we have exploited time-resolving small-angle X-ray scattering and electron microscopy together with neutron scattering to probe and quantify the different scales of structure and their evolution. We highlight new neutron scattering instrumentation which we believe have great potential in the growing field of hierarchical structures in polymers. The addition of small quantities of nanoparticles to conventional and sustainable thermoplastics leads to property enhancements with considerable potential in a number of areas Most engineered nano-particles are highly stable and these exist as nano-particles prior to compounding with the polymer resin, they remain as nano- particles during the active use as well as in the subsequent waste and recycling streams. In this work we also explore the potential for constructing nano-particles within the polymer matrix during processing from organic compounds selected to provide nano

关键词： Component Semi-Crystalline Polymers Morphology Texture Nucleation Growth Shear Flow

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

功能性运动筛查在老年人群中的应用（英文）

journal of Sport and Health Science 2016年第1期5卷 119-125页

作者： Ulrike H.mitchell A.Wayne johnson Pat R.Vehrs j.Brent Feland Sterling C.Hilton Department of Exercise Sciences Brigham Young University Provo UT 84602 USA Department of Educational Leadership and Foundations David O. McKay School of Education Brigham Young University Provo UT 84602 USA

Background:The Functional Movement Screen(FMS^(TM)) has become increasingly popular for identifying functional limitations in basic functional *** exploratory and descriptive study was undertaken to confirm feasibility of performing the FMS^(TM) in older active adults,assess prevalence of asymmetries and to evaluate the relationship between functional movement ability,age,physical activity levels and body mass index(BMI).Methods:This is an observational study;97 men(n = 53) and women(n = 44) between the ages of 52 and 83 *** was computed and self-reported physical activity levels were *** were grouped by age(5-year intervals),BMI(normal,over-weight,and obese)and *** participant's performance on the FMS^(TM) was digitally recorded for later ***:The youngest age group(50–54 years) scored highest in all seven tests and the oldest age group(75+) scored lowest in most of the tests compared to all other age *** subjects in the 'normal weight' group performed no different than those who were in the 'overweight' group;both groups performed better than the 'obese' *** the 97 participants 54 had at least one *** pairwise correlations between the total FMS^(TM) score and age(r =-0.531),BMI(r =-0.270),and the measure of activity level(r = 0.287) were significant(p juries in the older population.

关键词：运动测试老年活动性不对称性活动水平成人年龄组 FMS

维普期刊数据库

在线全文

学校读者我要写书评

暂无评论

青春论青年期的特性

Tranexamic acid for intracerebral haemorrhage within 2 hours of onset: protocol of a phase Ⅱ randomised placebo-controlled double-blind multicentre trial

1990年

作者：（加）米切尔（mitchell j.j.）张进辅译

本书介绍了青春期的特征和青春期的三个阶段,并对其进行了系统详细的分析和说明,

ISBN: (纸本)7219017227

本书介绍了青春期的特征和青春期的三个阶段,并对其进行了系统详细的分析和说明,

关键词：青春期青少年心理学

来源：汇雅图书（南通市图书馆... 评论

在线全文

汇雅图书（南通市图书馆）

学校读者我要写书评

暂无评论

Stroke & Vascular Neurology 2022年第2期7卷 158-165页

作者： Nawaf Yassi Henry Zhao Leonid Churilov Bruce C V Campbell Teddy Wu Henry Ma Andrew Cheung Timothy Kleinig Helen Brown Philip Choi jiann-Shing jeng Annemarei Ranta Hao-Kuang Wang Geoffrey C Cloud Rohan Grimley Darshan Shah Neil Spratt Der-Yang Cho Karim Mahawish Lauren Sanders john Worthington Ben Clissold Atte Meretoja Vignan Yogendrakumar Mai Duy Ton Duc Phuc Dang Nguyen Thai My Phuong Huy-Thang Nguyen Chung Y Hsu Gagan Sharma Peter j mitchell Bernard Yan Mark W Parsons Christopher Levi Geoffrey A Donnan Stephen M Davis Department of Medicine and Neurology Melbourne Brain Centre at The Royal Melbourne HospitalThe University of MelbourneParkvilleVictoriaAustralia Population Health and Immunity Division Walter and Eliza Hall Institute of Medical ResearchParkvilleVictoriaAustralia Ambulance Victoria MelbourneVictoriaAustralia Melbourne Medical School The University of MelbourneMelbourneVictoriaAustralia Stroke Division The Florey Institute of Neuroscience and Mental HealthParkvilleVictoriaAustralia Department of Neurology Christchurch HospitalChristchurchNew Zealand Department of Neurology Monash Medical CentreMonash UniversityClaytonVictoriaAustralia Department of Interventional Neuroradiology Liverpool HospitalLiverpoolNew South WalesAustralia Department of Neurology Royal Adelaide HospitalAdelaideSouth AustraliaAustralia Department of Neurology Princess Alexandra HospitalWoolloongabbaQueenslandAustralia Department of Neurology Box Hill HospitalEastern HealthBox HillVictoriaAustralia Stroke Centre and Department of Neurology National Taiwan University HospitalTaipeiTaiwan Department of Medicine Dunedin School of MedicineUniversity of OtagoWellingtonNew Zealand Department of Neurosurgery E-Da HospitalYanchaoKaohsiungTaiwan Department of Neurology Alfred HospitalMelbourneVictoriaAustralia Department of Clinical Neuroscience Monash University Central Clinical SchoolMelbourneVictoriaAustralia Department of Medicine Sunshine Coast University HospitalNambourQueenslandAustralia Department of Neurology Gold Coast University HospitalSouthportQueenslandAustralia Department of Neurology John Hunter HospitalThe University of NewcastleNewcastleNew South WalesAustralia Department of Neurosurgery China Medical University HospitalTaichungTaiwan Department of Internal Medicine Palmerston North HospitalPalmerston NorthNew Zealand Department of Neurology St Vincent's HospitalFitzroyVictoriaAustralia Department of Neurology Royal Prince Alfred HospitalCamperdownNew South WalesAustra

Rationale Haematoma growth is common early after intracerebral haemorrhage(ICH),and is a key determinant of *** acid,a widely available antifibrinolytic agent with an excellent safety profile,may reduce haematoma *** and design Stopping intracerebral haemorrhage with tranexamic acid for hyperacute onset presentation including mobile stroke units(STOP-MSU)is a phase Ⅱ double-blind,randomised,placebo-controlled,multicentre,international investigator-led clinical trial,conducted within the estimand statistical *** In patients with spontaneous ICH,treatment with tranexamic acid within 2 hours of onset will reduce haematoma expansion compared with *** size estimates A sample size of 180 patients(90 in each arm)would be required to detect an absolute difference in the primary outcome of 20%(placebo 39%vs treatment 19%)under a two-tailed significance level of *** adaptive sample size re-estimation based on the outcomes of 144 patients will allow a possible increase to a prespecified maximum of 326 *** Participants will receive 1 g intravenous tranexamic acid over 10 min,followed by 1 g intravenous tranexamic acid over 8 hours;or matching *** efficacy measure The primary efficacy measure is the proportion of patients with haematoma growth by 24±6 hours,defined as either≥33%relative increase or≥6 mL absolute increase in haematoma volume between baseline and follow-up CT *** We describe the rationale and protocol of STOP-MSU,a phase Ⅱ trial of tranexamic acid in patients with ICH within 2 hours from onset,based in participating mobile stroke units and emergency departments.

关键词： placebo centre absolute

Selenium and Iodine Deficiencies and Selenoprotein Function

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

Biomedical and Environmental Sciences 1997年第2期10卷 129-135页

作者： jOHN R. ARTHUR FERGUS NICOL jULIE H. mitchell AND GEOFFREY j. BECKETT(Division Of Biochemical Sciences, Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK Cellular Endocrinology Unit,University Department of Clinical Biochemistry, The Royal In Division of Biochemical Sciences Rowett Research Institute Aberdeen UK.

This paper reviews some recent findings on the interactions between selenium deficiency and iodine deficency. Both micronutrients can control the levels of selenoprotein mRNAs, particularly in the thyroid and brain. When selenium and iodine supplies are limiting the compensatory mechanisms work to minimise adverse effects on thyroid hormone metabolsm and thus neurological developtnent. The mechanisms for regulation of selenoproteins in selenium and iodine deficiency are however very tissue-specific. For example, unlike the brain and thyroid,brown adipose tissue is unable to retain selenoproteins in selenium and iodine deficiency and is therefore at greater risk from injurious effects of the deficiencies.

关键词： gene Selenium and Iodine Deficiencies and Selenoprotein Function

维普期刊数据库