检索结果-南通市图书馆

Plant physiological changes along an encroachment gradient: an assessment of US Mid-Atlantic serpentine barrens

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2018年第6期11卷 853-865页

作者： Nicole A.Havrilchak Jessica l.Schedlbauer Department of Biology West Chester University750 S.Church StreetWest ChesterPA 19383USA

Aims Serpentine barrens of the Mid-Atlantic United States are globally rare,grass-dominated ecosystems thought to exclude C3 spe-cies and characterized by unique soil ***,like many grassland ecosystems globally,these sites are presently facing encroachment by surrounding *** this ecosystem,the tendril climbing vine,Smilax rotundifolia,forms dense thickets around bar-rens that typically precede forest *** numerous factors speculatively initiate and promote encroachment in these systems,few studies have examined photosynthetic responses of serpentine grasses to changes in resource availability initiated by encroachers or physiological ability of encroaching *** to colonize high-light barren *** sought to under-stand both environmental and physiological dynamics of encroach-ment along an irradiance gradient in these *** At three serpentine barren sites in southeastern Pennsylvania,physiological responses of the native grasses Sorghastrum nutans and Schizachyrium scoparium to increased shading by ***-folia were ***,the physiological performance of *** in the forest understory was compared to that in sunlit barrens ***-saturated photosynthesis(A_(sat)),stomatal conductance(g_(s)),instantaneous transpiration efficiency(ITE),maximum efficiency of photosystem II(F_(v)/F_(m)),midday leaf water potential(ψ_(leaf))and specific leaf area(SlA)were measured for all species over the course of the 2014 growing ***-way analyses of variance were used to assess changes in these param-eters across growing environments,as well as seasonally for each *** regression analyses were also performed to inves-tigate the influence of vapor pressure deficit(D)and leaf tempera-ture(T_(leaf))on A_(sat) and *** Findings light-saturated photosynthesis was significantly greater in ***-difolia growing in sun than in the shade(Ply in th

关键词： encroachment photosynthesis serpentine barren Schizachyrium scoparium Smilax rotundifolia Sorghastrum nutans

Pulse cyclophosphamide therapy for inflammatory bowel disease

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2006年第8期12卷 1278-1280页

作者： Zsolt Barta lászló Tóth Margit Zeher 3~(rd) Department of Medicine Faculty of MedicineMedical and Health Science CentreUniversity of DebrecenDebrecenHungary Department of pathology Faculty of MedicineMedical and Health Science CentreUniversity of DebrecenDebrecenHungary

AIM:To assess the efficacy of intravenous cyclophos-phamide pulse therapy for refractory inflammatory bowel.isease(IBD).METHODS:We included in our cohort eight patientswith(moderate/severe)steroid refractory IBD(4 withulcerative colitis and 4 with Crohn's disease).They allreceived 6 cycles of intravenous cyclophosphamide(800mg)per ***:patients entered into remission after the sec-ond/third cyclophosphamide *** activity *** were no side effects and *** thepatients went into long lasting *** Crohn's diseasepatients and 3 of 4 ulcerative colitis patients achievedcomplete *** patient with ulcerative colitisshowed an impressive clinical response but did not enterinto *** the maintenance,patients with Crohn'sdisease were treated with methotrexate(15 mg/wk)andpatients with ulcerative colitis were treated with azathio-prine(2.5 mg/kg body weight/d).CONClUSION:Remission was maintained in all pa-tients for 6 mo on the *** drug was well *** findings suggest that aggressive immuno-suppressive therapy may be useful in some refractorypatients and further controlled study should be consid-ered in order to fully evaluate this type of treatment as apotential therapy for IBD.

关键词： Crohn's disease Ulcerative colitis Cyclophos-phamide

The anti-scarring effect of corneal stromal stem cell therapy is mediated by transforming growth factorβ3

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Eye and Vision 2020年第1期7卷 512-525页

作者： lin Weng James l.Funderburgh Irona Khandaker Moira l.Geary Tianbing Yang Rohan Basu Martha l.Funderburgh Yiqin Du Gary Hin-Fai Yam Department of Ophthalmology University of Pittsburgh School of medicine203 Lothrop StreetPittsburghPA 15213USA Shanghai lanhe Optometry and Ophthalmology Clinic Shanghai 200032People’s Republic of China

Background:Corneal stromal stem cells(CSSC)reduce corneal inflammation,prevent fibrotic scarring,and regenerate transparent stromal tissue in injured *** effects rely on factors produced by CSSC to block the fibrotic gene *** study investigated the mechanism of the scar-free regeneration ***:Primary human CSSC(hCSSC)from donor corneal rims were cultivated to passage 3 and co-cultured with mouse macrophage RAW264.7 cells induced to M1 pro-inflammatory phenotype by treatment with interferonγand lipopolysaccharides,or to M2 anti-inflammatory phenotype by interleukin-4,in a Transwell *** timecourse expression of human transforming growth factorβ3(hTGFβ3)and hTGFβ1 were examined by immunofluorescence and ***β3 knockdown for>70%in hCSSC[hCSSC-TGFβ3(si)]was achieved by small interfering RNA ***ïve CSSC and hCSSC-TGFβ3(si)were transplanted in a fibrin gel to mouse corneas,respectively,after wounding by stromal *** clarity and the expression of mouse inflammatory and fibrosis genes were ***:hTGFβ3 was upregulated by hCSSC when co-cultured with RAW cells under M1 *** of hCSSC to wounded mouse corneas showed significant upregulation of hTGFβ3 at days 1 and 3 post-injury,along with the reduced expression of mouse inflammatory genes(CD80,C-X-C motif chemokine ligand 5,lipocalin 2,plasminogen activator urokinase receptor,pro-platelet basic protein,and secreted phosphoprotein 1).By day 14,hCSSC treatment significantly reduced the expression of fibrotic and scar tissue genes(fibronectin,hyaluronan synthase 2,Secreted protein acidic and cysteine rich,tenascin C,collagen 3a1 andα-smooth muscle actin),and the injured corneas remained ***,hCSSC-TGFβ3(si)lost these anti-inflammatory and anti-scarring functions,and the wounded corneas showed intense ***:This study has demonstrated that the corneal regenerative effect of hCSSC is mediated by TGFβ3,inducing a s

关键词： Cornea wound healing Corneal stromal stem cells TGFβ3 Inflammation Fibrosis

Step Sintering of Microwave Heating and MicrowavePlasma Heating for Alumina Ceramics

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 & Technology 1999年第5期15卷 419-422页

作者： Zhang, JS Cao, l Yang, YJ Diao, YX Shen, XX Chinese Acad Sci Met Res Inst Shenyang 110015 Peoples R China

The invention of microwave induced plasma during microwave heating makes it possible to confine plasma inside a crucible, in the pressure range of 1.33 pa to 0.5 Mpa, and above 900 degrees C. In this study, the step sintering of microwave heating and microwave plasma heating (SSMP) was proposed. In this process, microwave heating and plasma heating was ingeniously combined in one chamber, and vacuum was unnecessary for microwave induced plasma. In the first step, the microwave energy directly heated alumina ceramics to a given temperature, above which microwave will mainly ionize the gas and sustain a plasma. Then the plasma further heated alumina ceramics to the final temperature to finish sintering. Maintaining the advantages of microwave heating and plasma heating, this step sintering approach will overcome the limitation of both processes for processing ceramics, and it will be suitable for sintering all kinds of ceramics in principle.

关键词： Ceramic materials

内毒素诱导致新生大鼠肺损伤中肾病理改变及转录因子-κB和转化生长因子-β1表达的研究

在线全文

学校读者我要写书评

暂无评论

中国临床药理学杂志 2020年第5期36卷 514-517页

作者：崔维静赛依帕甘肃省人民医院儿科甘肃兰州730000

目的研究内毒素(lPS)诱导致新生大鼠肺损伤模型中肾病理改变及转录因子-κB(NF-κB)和转化生长因子-β1(TGF-β1)表达的变化。方法用3~5日龄SPF级大鼠尾部静脉注射lPS建立新生大鼠急性肺损伤(AlI)模型。实验分为对照组、6 h模型组和12 ... 详细信息

目的研究内毒素(lPS)诱导致新生大鼠肺损伤模型中肾病理改变及转录因子-κB(NF-κB)和转化生长因子-β1(TGF-β1)表达的变化。方法用3~5日龄SPF级大鼠尾部静脉注射lPS建立新生大鼠急性肺损伤(AlI)模型。实验分为对照组、6 h模型组和12 h模型组。按实验要求时间杀死大鼠,无菌留取标本。用全自动生化仪检测新生大鼠的肾功能,用试剂盒检测丙二醛(MDA)含量变化和超氧化物歧化酶(SOD)、总抗氧化能力(T-AOC)活性,用免疫组化法检测NF-κB和TGF-β1的表达水平。结果对照组、6 h模型组和12 h模型组的大鼠血清肌酸酐的含量分别为(15.02±0.48),(45.96±1.25)和(97.65±1.43)μmol·l^-1,血尿素氮的含量分别为(6.84±0.53),(10.35±0.84)和(14.68±0.25)μmol·l^-1,肾组织中MDA含量分别为(2.02±0.41),(3.21±0.63)和(5.01±0.18)nmol·mg^-1,SOD活性分别为(28.74±0.69),(18.25±0.36)和(14.58±0.15)U·g^-1,T-AOC活性分别为(2.38±0.25),(1.83±0.02)和(1.26±0.23)μmol·l-1,肾组织中NF-κB的相对表达量分别为(1.02±0.08),(1.43±0.19)和(1.87±0.14),TGF-β1的相对表达量分别为(0.97±0.04),(1.46±0.15)和(1.92±0.08),对照组的上述指标与6 h模型组和12 h模型组比较,差异均有统计学意义(均PlPS诱导致新生大鼠AlI模型的过程中,也会对肾造成一定的损伤;在对lPS的应激中,NF-κB/TGF-β1信号通路的氧化应激反应异常活化。

关键词：内毒素新生大鼠肺损伤肾病理改变转录因子-κB 转化生长因子-β1

GO/CNC薄层纳米复合膜的制备及性能研究

在线全文

学校读者我要写书评

暂无评论

中国给水排水 2024年第11期40卷 65-72页

作者：吕永涛杨雅馨吝力潘永宝崔双科王磊西安建筑科技大学环境与市政工程学院陕西西安710055 陕西省膜分离技术研究院陕西省膜分离重点实验室陕西西安710055 陕西省现代建筑设计研究院有限公司陕西西安710021

为改善纳滤膜的性能,利用纤维素纳米晶(CNC)修饰氧化石墨烯(GO),合成了具有良好分散性的GO/CNC复合纳米材料,之后通过界面聚合引入聚酰胺(pa)层中制得改性纳滤膜,并进行形貌结构表征和性能测试。研究发现,GO/CNC改性膜表面具有更明显的... 详细信息

为改善纳滤膜的性能,利用纤维素纳米晶(CNC)修饰氧化石墨烯(GO),合成了具有良好分散性的GO/CNC复合纳米材料,之后通过界面聚合引入聚酰胺(pa)层中制得改性纳滤膜,并进行形貌结构表征和性能测试。研究发现,GO/CNC改性膜表面具有更明显的凸起褶皱结构、更高的粗糙度及亲水性,在0.6 Mpa下纯水通量可达38.45 l(/m2·h),较pa原膜与GO改性膜分别提升了84.86%和53.92%,Na2SO4和NaCl截留率分别为95.47%和6.65%。经pH=4、4000 mg/l的NaClO溶液浸泡4 h后,pa原膜的归一化纯水通量增加了近50%,归一化Na2SO4截留率降至0.89,而GO/CNC改性膜的归一化纯水通量仅增加了13%,Na2SO4截留率几乎无影响。上述结果表明,GO/CNC的添加可显著提升复合纳滤膜的渗透通量,同时具有良好的Na2SO4/NaCl分离选择性与耐氯性能。

关键词：氧化石墨烯纤维素纳米晶纳滤膜界面聚合耐氯性

Effect of Nitrogen Content on Microstructures and Mechanical Properties of WB_2(N) Films Deposited by Reactive Magnetron Sputtering

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2015年第12期31卷 1217-1225页

作者： Y.M.liu D.Y.Deng H.lei Z.l.Pei C.l.Jiang C.Sun J.Gong Institute of Metal Research Chinese Academy of Sciences

In the present study,WB 2（N） films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron *** influence of N 2 partial pressure（P （N2）） on the film microstructure and characteristics is studied systematically,including the chemical composition,crystalline structure,residual stress,surface roughness as well as the surface and the cross-section ***,nano-indentation and ball-on-disk tribometer are performed to analyze the mechanical and tribological properties of the *** results show that the addition of nitrogen apparently leads to the change of the structure from（1 0 1） to（0 0 1） orientation then to the amorphous structure with the formation of BN *** the addition of nitrogen can greatly refine the grain size and microstructure of the ***,the residual stress of the film is also found to change from tensile to compressive stress as a function of P （N2）,and the compressive stress increases with P （N2）,The WB 2（N） films with small nitrogen content,which are deposited at P （N2） of 0.004 and 0.006 pa,exhibit better mechanical,tribological and corrosion properties than those of other *** increase of nitrogen content accelerates the formation of BN phase and fast decreases the film *** addition,the large N 2 partial pressure gives rise to the target poisoning accompanied by the increase of the target voltage and the decrease of the deposition rate.

关键词： Reactive magnetron sputtering Nanocomposites WB 2(N) films Residual stress Mechanical properties

在线全文

学校读者我要写书评

暂无评论

基于等效刚度法优化的风力机叶片刚度计算

中国测试 2024年第7期50卷 47-52页

作者：余浩马剑龙吕文春苏宏杰张鹏宇内蒙古工业大学能源与动力工程学院内蒙古呼和浩特010051 内蒙古自治区高校可再生能源工程研究中心内蒙古呼和浩特010051 风能太阳能利用技术教育部重点实验室内蒙古呼和浩特010051 内蒙古机电职业技术学院科技与职教研究中心内蒙古呼和浩特010070

风力机叶片刚度由于非线性且截面变化程度大的特点,针对叶片建模初期刚度的评估问题通常采用刚度展项分布图体现叶片刚度,存在评估叶片刚度的参考参数不够直接、宏观的问题。基于变刚度梁挠度计算的等效刚度法,将叶片等效成变截面悬臂梁... 详细信息

风力机叶片刚度由于非线性且截面变化程度大的特点,针对叶片建模初期刚度的评估问题通常采用刚度展项分布图体现叶片刚度,存在评估叶片刚度的参考参数不够直接、宏观的问题。基于变刚度梁挠度计算的等效刚度法,将叶片等效成变截面悬臂梁,根据叶片特征合理选取边界条件,以叶片建模的截面数据特点为基础,优化原始等效刚度法的计算方式,使该方法更加贴合叶片模型,从而适用于叶片,达到方法优化的目的。利用ANSYS有限元软件进行叶片的预应力模拟实验,得出叶片的挠度模拟数值,以该模拟计算的挠度值为参考,验证优化后方法的有效性。结果表明:优化后的等效刚度法得到的刚度值,在低均布载荷值22.5 pa下理论计算的挠度值与试验挠度值的误差达到9.68%,减小原始方法计算的误差贴近叶片模型,可用于叶片刚度估算,为叶片的刚度计算提供新方法。

关键词：风力机叶片刚度等效刚度法变截面悬臂梁叶片挠度

维普期刊数据库博看期刊

Bouveret syndrome masquerading as a gastric mass-unmasked with endoscopic luminal laser lithotripsy:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2020年第22期8卷 5701-5706页

作者： Swetha parvataneni Harshit S Khara David l Diehl Department of Internal Medicine Geisinger Lewistown HospitalLewistownPA 17044United States Department of Gastroenterology and Hepatology Advanced EndoscopyGeisinger Health systemDanvillePA 17822United States Department of Gastroenterology and Nutrition Geisinger Medical CenterDanvillePA 17822United States

BACKGROUND Bouveret syndrome,also known as gallstone ileus,is a rare form of gastric outlet obstruction accounting for 1%-3%of *** condition is most often reported in *** diagnosis can be challenging and is often missed due to atypical presentations,which occasionally mimic gastric outlet obstruction symptoms such as nausea,vomiting,loss of appetite and *** symptoms vary with stone *** stones are managed with a surgical approach,but this carries increased morbidity and *** the past decade,the endoscopic approach has emerged as an alternative mode of treatment,but it is generally unsuccessful in the management of larger-sized stones.A literature review revealed cases of successful endoscopic treatment requiring multiple sessions for stone sizes measuring up to about 4.5 *** we present a unique case of an elderly patient with Bouveret syndrome with a 5 cm stone mimicking a gastric mass and causing gastric outlet obstruction,who was successfully managed in a single session using a complete endoscopic approach with laser *** SUMMARY An 85-year-old female patient presented with 1-month history of intermittent abdominal pain,vomiting,decreased appetite and weight *** abdominal computed tomography showed a 4.5 cm×4.7 cm partially calcified mass at the gastric pylorus causing gastric outlet *** showed an ulcerated fistulous opening and a large 5 cm impacted gallstone in the duodenal *** nets and baskets were used in an attempt to remove the stone,but this approach was *** her advanced age,poor physical condition and underlying comorbidities,she was deemed to be high-risk for ***,a minimally invasive approach using endoscopic laser lithotripsy was attempted and successfully treated the ***-procedure,the patient experienced complete resolution of her symptoms with no complications and was able to tolerate her *** was subsequently discharged home

关键词： Gastric outlet obstruction Bouveret syndrome laser lithotripsy Holmium laser lithotripsy Holmium and neodymium yttrium aluminum garnet lasers Case report