检索结果-南通市图书馆

The molecular conformation of silk fibroin regulates osteogenic cell behavior by modulating the stability of the adsorbed protein-material interface

引用

Bone Research 2021年第2期9卷 188-199页

作者： Yanlin Long Xian Cheng john A.Jansen Sander G.C.Leeuwenburgh Jing Mao Fang Yang Lili Chen Department of Stomatology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration Wuhan 430022China Department of Dentistry–Biomaterials Radboud University Medical CenterPhilips van Leydenlaan 256525 EX NijmegenThe Netherlands Center of Stomatology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Silk fibroin(SF)can be used to construct various stiff material interfaces to support bone *** essential preparatory step is to partially transform SF molecules from random coils toβ-sheets to render the material water ***,the influence of the SF conformation on osteogenic cell behavior at the material interface remains ***,three stiff SF substrates were prepared by varying theβ-sheet content(high,medium,and low).The substrates had a comparable chemical composition,surface topography,and *** adsorbed fibronectin was used as a model cellular adhesive protein,the stability of the adsorbed protein-material interface,in terms of the surface stability of the SF substrates and the accompanying fibronectin detachment resistance,increased with the increasingβ-sheet content of the SF ***,(i)larger areas of cytoskeleton-associated focal adhesions,(ii)higher orders of cytoskeletal organization and(iii)more elongated cell spreading were observed for bone marrow-derived mesenchymal stromal cells(BMSCs)cultured on SF substrates with high ***β-sheet contents,along with enhanced nuclear translocation and activation of YAP/TAZ and ***,osteogenic differentiation of BMSCs was stimulated on highβ-sheet *** results indicated that theβ-sheet content influences osteogenic differentiation of BMSCs on SF materials in vitro by modulating the stability of the adsorbed protein-material interface,which proceeds via protein-focal adhesion-cytoskeleton links and subsequent intracellular *** findings emphasize the role of the stability of the adsorbed protein-material interface in cellular mechanotransduction and the perception of stiff SF substrates with differentβ-sheet contents,which should not be overlooked when engineering stiff biomaterials.

关键词： interface stability adsorbed

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Thiocyanate-induced labilization of schwertmannite: Impacts and mechanisms

引用

Journal of Environmental Sciences 2019年第6期31卷 218-228页

作者： Cong Fan Chuling Guo Junhui Zhang Cui Ding Xiaofei Li john R.Reinfelder Guining Lu Zhenqing Shi Zhi Dang School of Environment and Energy South China University of Technology The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of Education Department of Environmental Sciences Rutgers University

Schwertmannite is an amorphous iron(iii)-oxyhydroxysulfate that forms in acid mine drainage(AMD) environments. The characteristic of high heavy metal adsorption capability makes schwertmannite a potentially useful, environmentally friendly material in wastewater treatment. Unstable schwertmannite is prone to *** the mechanisms that induce schwertmannite labilization and affect its capacity to remove heavy metals are of great environmental and geochemical ***(SCNˉ) is a hazardous pseudohalide that is also normally found in ***, little is known about the impact of Fe(iii)-binding ligand SCNˉ on schwertmannite stability and its subsequent capacity to bind trace elements. Here, we investigated the adsorption of SCNˉ on schwertmannite and subsequent mineral transformation to characterize this little-known process. The appearance of Fe2+indicated that the interactions between schwertmannite and SCNˉ may involve complexation and reduction reactions. Results showed that the majority of the adsorbed-SCNˉ was immobilized on schwertmannite during the 60-days transformation. The transformation rates of schwertmannite increased with increasing concentrations of SCNˉ. Goethite was detected as the dominant transformation product with or without SCNˉ. The mechanisms of SCNˉ-promoted dissolution of schwertmannite can be described as follows:(1) formation of Fe(iii)–NCS complexes on the schwertmannite surface and in solution, a process which increases the reactivity of solid phase Fe(iii);(2) the extraction of Fe(iii) from schwertmannite by SCNˉ and subsequent schwertmannite dissolution; and(3) the formation of secondary minerals from extracted Fe(iii). These findings may improve AMD treatment strategies and provide insight into the use and potential reuse of schwertmannite as a trace element sorbent.

关键词： Thiocyanate Schwertmannite Stability Ligand-promoted dissolution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

序列运算离散化过程中的误差成因及补偿

引用

清华大学学报（自然科学版） 2009年第1期49卷 17-20页

作者：徐玮康重庆夏清 JIANG john N 清华大学电机工程与应用电子技术系电力系统国家重点实验室北京100084 School of Electrical and Computer engineering the University of OklahomaNormanOK73019USA

为了减少序列离散化过程导致的误差,提出几种概率补偿的方法。由误差的成因入手,分析了离散化过程的误差机理,将利用随机变量的概率分布函数离散化后所得序列,分别以修正公式、平均补偿法及比例补偿法进行补偿,推导出各种误差补偿方法... 详细信息

为了减少序列离散化过程导致的误差,提出几种概率补偿的方法。由误差的成因入手,分析了离散化过程的误差机理,将利用随机变量的概率分布函数离散化后所得序列,分别以修正公式、平均补偿法及比例补偿法进行补偿,推导出各种误差补偿方法下序列期望值及方差的误差估计公式。结果表明:经误差补偿后,算例中序列期望值误差下降为原误差的8%以下,而方差误差至少可降为原误差的91%。

关键词：序列运算理论电力系统离散化误差补偿

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Silicon nitride passive and active photonic integrated circuits:trends and prospects

引用

Photonics Research 2022年第6期10卷 I0001-I0015页

作者： CHAO XIANG WARREN JIN john E.BOWERS Department of Electrical and Computer Engineering University of CaliforniaSanta BarbaraSanta BarbaraCalifornia 93106USA

The use of silicon nitride in integrated photonics has rapidly progressed in recent ***-low-loss waveguides based on silicon nitride are a favorable platform for the research of nonlinear and microwave photonics and their application to a wide variety of fields,including precision metrology,communications,sensing,imaging,navigation,computation,and quantum *** recent years,the integration of Si and Ⅲ-Ⅴ materials has enabled new large-scale,advanced silicon nitride-based photonic integrated circuits with versatile *** this perspective article,we review current trends and the state-of-the-art in silicon nitride-based photonic devices and *** highlight the hybrid and heterogeneous integration of Ⅲ-Ⅴ with silicon nitride for electrically pumped soliton microcomb generation and ultra-low-noise lasers with fundamental linewidths in the tens of m Hz *** also discuss several ultimate limits and challenges of silicon nitride-based photonic device performance and provide routes and prospects for future development.

关键词： passive pumped nitride

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of Extreme Air Temperature and Humidity on the Insecticidal Expression Level of Bt Cotton

引用

Journal of Integrative Agriculture 2012年第11期11卷 1836-1844页

作者： CHENYuan WEN Yu-jin CHEN Yuan john Tom Cothren ZHANG Xiang WANG Yong-hui WilliamA Payne CHEN De-hua Ecology and Cultivation in Middle and Lower Reaches of Yangtse River Ministry of Agriculture/Agricultural College Yangzhou University Yangzhou 225009 P.R.China Department of Soil and Crop Sciences Texas A&M University College Station TX77843 USA Key Laboratory of Crops Genetics and Physiology Jiangsu Province/Agricultural College Yangzhou University Yangzhou 225009 P.R. China norman Borlaug Institute for International Agriculture Texas A&M University College Station TX77843 USA

The higher survival rates of Helicoverpa amigera larvae were usually observed after adverse climate which was related to extreme temperature （T） and relative humidity （RH） stresses in transgenic Bacillus thuringiensis （Bt） cotton. The unstable resistance of Bt cotton to bollworms has been correlated with the reduced expression of CrylAc δ-endotoxin. The objective of this study was to investigate the effects of combined temperature and relative humidity stresses on the leaf CrylAc insecticidal protein expression during critical developmental stages. The study was undertaken on two transgenic cotton cultivars that share same parental background, Sikang 1 （a conventional cultivar） and Sikang 3 （a hybrid cultivar）, during the 2007 and 2008 growing seasons at the Yangzhou University Farm, Yangzhou, China. The study was arranged with two factors that consisted of temperature （two levels） and relative humidity （three levels）. The six T/RH treatments were 37℃/95%, 37℃/70%, 37℃/50%, 18℃/95%, 18℃/70%, and 18℃/50%. In 2007, the six treatments were imposed to the plants at peak flowering stage for 24 h; in 2008, the six treatments were applied to the plants at peak square, peak flowering, and peak boll stages for 48 h. The results of the study indicated that the leaf insecticidal protein expression in CrylAc was significantly affected by extreme temperature only at peak flowering stage, and by both extreme temperature and relative humidity during boll filling stage. The greatest reductions were observed when the stresses were applied at peak boll stage. In 2008, after 48 h stress treatment, the leaf Bt endotoxin expression reduced by 25.9-36.7 and 23.6-40.5% at peak boll stage, but only by 14.9-26.5 and 12.8-24.0% at peak flowering stage for Sikang 1 and Sikang 3, respectively. The greatest reduction was found under the low temperature combined with low relative humidity condition for both years. It is believed that the temperature and relative humidity stresses may be attribut

关键词： Bt cotton high temperature low temperature relative humidity CryIAc protein

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Coping with extremes:convergences of habitat use,territoriality,and diet in summer but divergences in winter between two sympatric snow finches on the Qinghai-Tibet Plateau

引用

Integrative Zoology 2020年第6期15卷 533-543页

作者： Dongming LI Jason E.DAVIS Yanfeng SUN Gang WANG Ghulam NABI john C.WINGFIELD Fumin LEI Key Laboratory of Animal Physiology Biochemistry and Molecular Biology of Hebei ProvinceCollege of Life SciencesHebei Normal UniversityShijiazhuangHebei ProvinceChina Key Laboratory of Zoological Systematics and Evolution Institute of ZoologyChinese Academy of SciencesBeijingChina Department of Neurobiology Physiology and BehaviorUniversity of CaliforniaDavisCaliforniaUSA Department of Biology Radford UniversityRadfordVirginiaUSA Ocean College Hebei Agricultural UniversityQinhuangdaoHebei ProvinceChina University of Chinese Academy of Sciences BeijingChina Center for Excellence in Animal Evolution and Genetics Chinese Academy of SciencesKunmingChina

On the Qinghai-Tibet Plateau,extreme environmental conditions have imposed intense selective pressure on the evolution of phenotypic traits of wild *** date,limited information is available on behavioral and ecological traits concerning niche differentiation among sympatric animals on the Qinghai-Tibet Plateau,especially during winter when the environments are most ***,we studied the seasonal variations in habitat occurrence,territorial behavior,and diet in two sympatric snow finches(the white-rumped snow finch,Onychostruthus taczanowskii,WRSF;and the rufous-necked snow finch,Pyrgilauda ruficollis,RNSF)to determine convergence and divergence of ecological traits in such severe climatic *** results showed that:(i)WRSF occupied rural areas as a dominant species throughout the annual cycle while RNSF occupied the rural areas in summer and then shifted to human-occupied areas in winter and spring;(ii)WRSFs exhibited robust aggressive behavior and territoriality during winter relative to RNSFs;(iii)the diets of both species varied with the season but did not vary between species except that WRSF ate significantly more seeds but RNSF consumed more starchy material derived from human food waste during ***,the separations in the spatial niche and territoriality between WRSF and RNSF,especially in winter,may contribute to alleviating the pressure of interspecific competition,and promoting the coexistence of the two sympatric snow finches in the extreme environments on the Qinghai-Tibet Plateau.

关键词： diet habitat use Qinghai-Tibet Plateau snow finch territorial behavior

来源：

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

The influence of habitat heterogeneity and latitude on gamma diversity of the Nearctic Simuliidae, a ubiquitous group of stream-dwelling insects

引用

Insect Science 2018年第4期25卷 712-720页

作者： john W. McCreadie Rachel H. Williams Sam Stutsman Debra S. Finn Peter H. Adler Department of Biology University of South Alabama Mobile Alabama USA Department of Earth Sciences Biology University of South Alabama Mobile Alabama USA Department of Integrative Biology Oregon State University Corvallis Oregon USA Department of Plant and Environmental Sciences Clemson University Clemson South Carolina USA

Among the most prominent, large-scale patterns of species richness are the increases in richness with decreasing latitude and with increasing habitat heterogeneity. Using the stream-dwelling larval and pupal stages of North American black flies （Diptera： Simuliidae）, we address 3 broad questions about species richness：（i） Does a significant latitude-richness relationship exist？（ii） How does habitat heterogeneity influence gamma diversity？（iii） What is the sign （positive or negative） of the latitude-richness and the heterogeneity-richness relationships？ We found no evidence that habitat heterogeneity influences gamma diversity. The estimated peak species richness for black flies in North America was at 50-53°N, which also corresponds with peak generic richness. All plesiomorphic, extant lineages of the Simuliidae in the Western Hemisphere are found in cool mountainous environments of North America, suggesting that peak richness at 50-53°N might be a signature of this phylogenetic pattern and a reflection of underlying historical processes

关键词： aquatic insects biodiversity gamma richness North America Simuliidae streams

来源：

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

Historic distribution and driving factors of human-caused fires in the Chinese boreal forest between 1972 and 2005

引用

Journal of Plant Ecology 2015年第5期8卷 480-490页

作者： Futao Guo john L.Innes Guangyu Wang Xiangqing Ma Long Sun Haiqing Hu Zhangwen Su Faculty of Forestry Fujian Agriculture and Forestry UniversityNo.15 Shangxiadian RoadFuzhou 350002China Sustainable Forest Management Laboratory Faculty of ForestryUniversity of British Columbia2424 Main MallVancouverBritish Columbia V6T 1Z4Canada Faculty of Forestry Northeast Forestry UniversityNo.26 Hexing RoadHarbinHeilongjiang Province 150040China

Aims The pattern and driving factors of forest fires are of interest for fire occurrence prediction and forest fire *** aims of the study were:(i)to describe the history of human-caused fires by season and size of burned area over time;(ii)to identify the spatial patterns of human-caused fires and test for the existence of‘hotspots’to determine their exact locations in the Daxing’an mountains;(iii)to determine the driving factors that determine the spatial distribution and the possibility of human-caused fire *** In this study,K-function and Kernel density estimation were used to analyze the spatial pattern of human-caused *** analysis was conducted in s-plus and arcgIs environments,*** analysis of driving factors was performed in SPSS 19.0 based on a logistic regression *** variables used to identify factors that influence fire occurrence included vegetation types,meteorological conditions,socioeconomic factors,topography and infrastructure factors,which were extracted and collected through the spatial analysis mode of arcgIs and from official statistics,*** Findings The annual number of human-caused fires and the area burnt have declined since 1987 due to the implementation of a forest fire protection *** were significant spatial heterogeneity and seasonal variations in the distribution of human-caused fires in the Daxing’an *** heterogeneity was caused by elevation,distance to the nearest railway,forest type and temperature.a logistic regression model was developed to predict the likelihood of human-caused fire occurrence in the Daxing’an mountains;its global accuracy attained 64.8%.The model was thus comparable to other relevant studies.

关键词： anthropogenic fire spatial distribution K-function Kernel intensity estimation boreal forest logistic regression

来源：

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

Parasitic Plants <i>Striga</i>and <i>Phelipanche</i>Dependent upon Exogenous Strigolactones for Germination Have Retained Genes for Strigolactone Biosynthesis

引用

American Journal of Plant Sciences 2015年第8期6卷 1151-1166页

作者： Malay Das Monica Fernández-Aparicio Zhenzhen Yang Kan Huang norman J. Wickett Shannon Alford Eric K. Wafula Claude dePamphilis Harro Bouwmeester Michael P. Timko john I. Yoder James H. Westwood Department of Plant Pathology Physiology and Weed Science Virginia Tech Blacksburg VA USA Department of Biological Sciences Presidency University Kolkata India Institute for Sustainable Agriculture Department of Plant Breeding Spanish National Research Council Córdoba Spain Department of Biology Institute of Molecular Evolutionary Genetics Pennsylvania State University University Park PA USA Department of Biology University of Virginia Charlottesville VA USA Chicago Botanic Garden Glencoe IL USA Laboratory of Plant Physiology Wageningen University Wageningen Netherlands Department of Plant Sciences University of California Davis Davis CA USA

Strigolactones are plant hormones with multiple functions, including regulating various aspects of plant architecture such as shoot branching, facilitating the colonization of plant roots by arbuscular mycorrhizal fungi, and acting as seed germination stimulants for certain parasitic plants of the family Orobanchaceae. The obligate parasitic species Phelipanche aegyptiaca and Striga hermonthica require strigolactones for germination, while the facultative parasite Triphysaria versicolor does not. It has been hypothesized that P. aegyptiaca and S. hermonthica would have undergone evolutionary loss of strigolactone biosynthesis as a part of their mechanism to enable specific detection of exogenous strigolactones. We analyzed the transcriptomes of P. aegyptiaca, S. hermonthica and T. versicolor and identified genes known to act in strigolactone synthesis (D27, CCD7, CCD8, and MAX1), perception (MAX2 and D14) and transport (PDR12). These genes were then analyzed to assess likelihood of function. Transcripts of all strigolactone-related genes were found in P. aegyptiaca and S. hermonthica, and evidence points to their encoding functional proteins. Gene open reading frames were consistent with homologs from Arabidopsis and other strigolactone-producing plants, and all genes were expressed in parasite tissues. In general, the genes related to strigolactone synthesis and perception appeared to be evolving under codon-based selective constraints in strigolactone-dependent species. Bioassays of S. hermonthica root extracts indicated the presence of strigolactone class stimulants on germination of P. aegyptiaca seeds. Taken together, these results indicate that Phelipanche aegyptiaca and S. hermonthica have retained functional genes involved in strigolactone biosynthesis, suggesting that the parasites use both endogenous and exogenous strigolactones and have mechanisms to differentiate the two.

关键词： Broomrape Phelipanche Striga Strigolactone Triphysaria Witchweed

来源：

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

Cross-cultural psychometric assessment of the parent-teen sexual risk communication (PTSRC-iii) scale in Jamaica

引用

Open Journal of Preventive Medicine 2012年第2期2卷 205-213页

作者： norman K. Waldron M. Katherine Hutchinson Hermi H. Hewitt Pansy I. Hamilton Department of Community Health and Psychiatry The University of the West Indies (UWI) Kingston Jamaica Hugh Wynter Fertility Management Unit Faculty of Medical Sciences The University of the West Indies (UWI) Kingston Jamaica New York University College of Nursing New York USA The UWI School of Nursing The University of the West Indies (UWI) Kingston Jamaica

Background: HIV/AIDS represents a serious health threat in Jamaica. Adolescent and young adult females are at particularly high risk. US studies have shown that parent-teen sexual communication may significantly influence the sexual risk-related beliefs and behaviors. However, no studies have examined parent-teen sexual communication in Jamaica or the wider Caribbean. Objective: The study aims to describe patterns of parent-teen sexual communication between Jamaican mothers and adolescent daughters and assess the psychometric properties of the Parent-Teen Sexual Risk Communication (PTSRC-iii) scale when used with this population. Method: Data were collected as part of a larger randomized controlled trial study. A total of 330 urban Jamaican adolescent girls, ages 13 - 17, and their mothers or female guardians completed the 8-item PTSRC-iii scale at baseline and 3-month follow-up. Results: Mothers’ and daughters’ scores covered the full range of possible scores. Internal reliability of the PTSRC-iii scale was excellent (α = 0.92 and 0.93 for mothers and daughters, respectively). There was evidence of consistency over time (r = 0.57, p r = 0.27, p r = 0.427, p r = 0.146, p = 0.008). A two-factor structure was identified, although the second factor showed a lower eigen-value than was found in previous US studies. The loading pattern and explanation of variance were very similar to the factor 2 described in the initial psychometric testing of the PTSRC-iii instrument. Discussion: Patterns of sexual communication and the psychometrics of the scale when used in Jamaica were consistent with US results, and provided evidence of the cross-cultural reliability and validity of the PTSRC-iii scale.

关键词： Adolescent Sexual Risk Sexual Communication Psychometric Assessment Reliability

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：