检索结果-南通市图书馆

The anatomic determinants of conductive hearing loss secondary to tympanic membrane perforation

Journal of Otology 2017年第3期12卷 125-131页

作者： David J.Carpenter Debara L.Tucci David M.Kaylie Dennis O.Frank-Ito Division of Head and Neck Surgery & Communication sciences Department of Surgery Duke University Medical Center Durham NC USA Computational Biology & Bioinformatics phd Program Duke University Durham NC USA Department of Mechanical Engineering and Materials science Duke University Durham NC USA

Objectives: Recent studies have introduced middle ear volume(MEV) as a novel determinant of perforation-induced conductive hearing loss(CHL) in a mechanism driven by trans-tympanic membrane pressure differences. The primary aims of this preliminary report are to: 1) correlate CHL with perforation size; 2) describe the relationship between CHL and MEV; and 3) compare CHL across a range of cholesteatoma ***: A retrospective pilot study was performed in 31 subjects with audiometry indicative of conductive hearing loss, temporal bone CT scans,and no prior middle ear surgery. Perforation size and MEV were analyzed with respect to CHL in a cohort of 10 perforated ears with no cholesteatoma. CHLs were compared in 3 groups defined by extent of cholesteatoma ***: Ears with large and small perforations showed mean ABG values of 32.0 ± 15.7 dB and 16.0 ± 16.4 dB, respectively. A direct relationship was observed between MEV and CHL for ears with large perforations across all frequencies, whereas this relationship for small perforations was frequency-dependent. Finally, a statistically significant increase in CHL was found across ears with increasing cholesteatoma involvement at 1000 Hz(X^2(2) = 9.786, p = 0.008),2000 Hz(x^2(2) = 8.455, p = 0.015),and 4000 Hz(x^2(2)= 8.253, p = 0.016).Conclusions: These pilot data suggest that greater perforation-induced conductive hearing losses may be associated with larger perforation sizes and cholesteatoma. The correlation between MEV and CHL may require additional study.

关键词： Perforation-induced hearing loss Conductive hearing loss Middle ear volume Three-dimensional volume reconstruction

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

Accuracy Improvement of ASTER Stereo Satellite Generated DEM Using Texture Filter

引用

Geo-Spatial Information science 2010年第4期13卷 257-262页

作者： Mandla V.Ravibabu Kamal Jain Surendra Pal Singh Naga Jyothi Meeniga center for GIS School of Geography and Environmental ScienceMonash UniversityClayton CampusVICAustralia Environmental Water Resource and Transportation Engineering DivisionSchool of Mechanical & Building ScienceVellore Institute of Technology(VIT)-University Vellore-632 014Tamil NaduIndia Geomatics Engineering Section Department of Civil EngineeringIndian Institute of Technology RoorkeeRoorkee-247667U.A.India Post Graduate student(GST) Institute of Science and TechnologyJNTUHyderabadIndia

The grid DEM(digital elevation model) generation can be from any of a number of sources:for instance,analogue to digital conversion of contour maps followed by application of the TIN model,or direct elevation point modelling via digital photogrammetry applied to airborne images or satellite ***,apart from the deployment of point-clouds from LiDAR data acquisition,the generally favoured approach refers to applications of digital *** of the most important steps in such deployment is the stereo matching process for conjugation point(pixel) establishment:very difficult in modelling any homogenous areas like water cover or forest canopied areas due to the lack of distinct spatial *** a result,application of automated procedures is sure to generate erroneous elevation *** this paper,we present and apply a method for improving the quality of stereo DEMs generated via utilization of an entropy texture *** filter was applied for extraction of homogenous areas before stereo matching so that a statistical texture filter could then be applied for removing anomalous evaluation values prior to interpolation and accuracy assessment via deployment of a spatial correlation *** exemplification,we used a stereo pair of ASTER 1B images.

关键词： ASTER digital elevation model extraction stereo matching texture filter quality improvement

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

Biodegradation of natural and synthetic estrogens in moving bed bioreactor

引用

Chinese Journal of Chemical Engineering 2018年第2期26卷 393-399页

作者： Mohammad Mehdi Amin Bijan Bina Karim Ebrahim Zeynab Yavari Farzaneh Mohammadi Environment Research center Research Institute for Primordial Prevention of Non-communicable Disease Isfahan University of Medical Sciences Department of Environmental Health Engineering School of Health Isfahan University of Medical Sciences student Research Committee Isfahan University of Medical Sciences

Estrogen hormones as a group of endocrine disruptive compounds （EDC） can interfere with endocrine system in humans and animals. The goal of this study was to investigate the elimination rate of Estrone （El）, 17β-estradiol （E2） and 17α-ethinyl estradiol （EE2） in Moving Bed Bioreactor （MBBR）. These analytes extracted by Dispersive Liquid-Liquid Microextraction （DLLME） technique, followed by derivatization, and detected by GC/MS. Estrogen removal efficiency in MBBR improved at high solid retention times （SRTs）, which notion is owing to development ofnitrification. Estrogenspecificremovalratewasbetween 0,22-1.45μg.（gVSS） 1.d -1 for natural and synthetic hormones. The adsorption rate was 0.9%-3.2% 0-1.3%, and 0.7%-5.7% for E1, E2, and EE2, respectively. In addition, the biodegradation rates were more than 95% for these compounds. These results illustrated that in MBBR, the hiodegradation and the adsorption to biomass are considered as two significant routes for elimination of estrogenic compounds. As a whole, the deterioration rate of estrogens enhanced by MBBR compared to other biological wastewater treatment processes such as conventional activated sludge.

关键词： Estrogen hormones Adsorption Biodegradation Nitrification

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 Parental Migration on Mental Health of Left-behind Children： Evidence from Northwestern China

引用

China & World Economy 2016年第3期24卷 105-122页

作者： Yaojiang Shi Yu Bai Yanni Shen, Kaleigh Kenny Scott Rozelle Professor Center for Experimental Economics in Education Shaanxi Normal University China. phd candidate Center for Chinese Agricultural Policy Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences University of Chinese Academy of Sciences China. Graduate student Center for Experimental Economics in Education Shaanxi Normal University China. Research Assistant Freeman Spogli Institute for International Studies Stanford University USA. Professor Freeman Spogli Institute for International Studies Stanford University USA.

China＇s rapid development and urbanization have induced large numbers of rural residents to migrate from their homes in the countryside to urban areas in search of higher wages. It is estimated that there are more than 60 million ＂left-behind children ＂＂（LBC） remaining in the countryside after their parents migrate, typically living with surrogate caregivers. Extensive research has focused on the impact of parental out- migration on children＇s mental health, but less attention has been paid to the effects of parental return-migration. The present paper examines the changes in mental health before and after the parents of fourth and fifih grade students out-migrate or return-migrate. We draw on a panel dataset collected by the authors of more than 19 000 students from 252 rural primary schools in northwestern China. Using DID and propensity score matching approaches, our results indicate that parental out-migration has a significant negative impact on the mental health of LBC, as they tend to exhibit higher levels of anxiety and lower levels of self-esteem. However, we find that parental return-migration has no significant effect on the mental health of LBC.

关键词： left-behind children mental health out-migration return-migration rural China

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

Influence of impurities on microstructure and mechanical properties of ZK60 magnesium alloy

引用

Transactions of Nonferrous Metals Society of China 2010年第7期20卷 1299-1304页

作者：潘复生毛建军陈先华彭建王敬丰 College of Materials science and Engineering Chongqing University National Engineering Research center for Magnesium Alloys Chongqing University

The influence of impurity content on the microstructure and mechanical properties of ZK60 magnesium alloys was investigated by optical microscopy,scanning electron microscopy and tensile ***60 alloys were prepared by changing holding time of alloy melt during semi-continuous casting in order to control the content of impurity *** alloy with lower purity content is found to have less second precipitates and larger grain size in the as-cast ***,in the as-extruded state,reducing impurities brings about a decrease in grain size and an increase in yield strength from 244 MPa to 268 MPa,while the elongations in the as-extruded alloys with different contents of impurities are almost the *** T5 treatment,impurity content is found to have more obvious effect on the yield strength of ZK60 *** yield strength of ZK60-45 alloys with low impurity content is increased up to 295 MPa after T5 treatment.

关键词： ZK60 magnesium alloy impurities mechanical properties microstructure extrusion T5 treatment

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

Stereocomplexation and Mechanical Properties of Polylactide-bpoly(propylene glycol)-b-polylactide Blend Films: Effects of Polylactide Block Length and Blend Ratio

引用

Chinese Journal of Polymer science 2017年第11期35卷 1391-1401页

作者： Dutchanee Pholharn Onanong Cheerarot Yodthong Baimark Biodegradable Polymers Research Unit Department of Chemistry and Center of Excellence for Innovation in ChemistryFaculty of Science Mahasarakham University

In the present work, poly（propylene glycol）（PPG） was block copolymerized to form polylactide-poly（propylene glycol）-polylactide （PL-PPG-PL） triblock copolymers for preparing flexible stereocomplex PL （scPL） blend films. The scPL blend films were prepared by solution blending of poly（L-lactide）-PPG-poly（L-lactide）（PLL-PPG-PLL） and poly（D-lactide）- PPG-poly（D-lactide）（PDL-PPG-PDL） triblock copolymers before film casting. The influences of PL end-block lengths （2 ×10^4 and 4×10^4 g/tool） and blend ratios （75/25, 50/50 and 25/75 W/W） on the stereocomplexation and mechanical properties of the blend films were evaluated. From DSC and WAXD results, the 50/50 blend films had complete stereocomplexation. Phase separation between the scPL and PPG phases was not observed from their SEM images. The tensile stress and elongation at break increased with the sterecomplex crystallinities and PL end-block lengths. The PPG middle-blocks enhanced elongation at break of the scPL films. The results showed that the PL-PPG-PL triblock structures did not affect stereocomplexation of the PLL/PDL block blending. In conclusion, the phase compatibility and flexibility of the scPL films were improved by PPG block copolymerization.

关键词： Stereocomplex Polylactide Poly(propylene glycol) Block copolymers Mechanical properties

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

Rangeland Privatization and Its Impacts on the Zoige Wetlands on the Eastern Tibetan Plateau

引用

Journal of Mountain science 2005年第2期2卷 105-115页

作者： YAN Zhaoli WU Ning phd assistant professor from Chengdu Institute of Biology Chinese Academy of Sciences and a rangeland specialist at the International Center for Integrated Mountain Development （ICIMOD） phd supervisor professor and executive deputy director of Chengdu Institute of Biology Chinese Academy of Sciences

The high Zoige Basin （Ruoergai Plateau） on the eastern Tibetan Plateau is a fault depression formed during intensive uplifting of the Tibetan Plateau. The wetland is globally important in biodiversity and is composed of marshes, bogs, fens, wet meadows and shallow water interspersed with low hills and sub-alpine meadows. Most of the Zoige wetlands have long been one of the most important grazing lands in China. Recent rangeland policy has allowed grazing, and usable wetland areas have been being legally allocated to individuals or groups of households on a long-term lease basis. Privatizafion of the wetland has impacted the Zoige wetlands in aspects of hydrologic condition, landscape and biodiversity. The uneven spatial distribution of water resources onprivatelands has led to the practice of extracting ground water, which has decreased the perched water table in Zoige. Fencing off the rangelands and grazing on expanding sand dunes have affected landscapes. Variation in the water table has led to the changes in vegetation diversity, resulting in the changes in wildlife and aquatic diversities and ecosystem processes. Making use all year round of the pasture that was previously grazed only in summer has shrunk the daily activity space of wildlife, and the newly erected fences blocked the movement of wild animals looking for food in the snow to lower and open areas. To maintain the favorable conditions of the Zoige wetland ecosystem, the author suggests that, in addition to biophysical research and implementation of conservation practices, there is an immediate need to initiate an integrated management program, increase public awareness of wetland functions and provide better training for the local conservation staff.

关键词： Tibetan Plateau rangeland privatization Zoige (Ruoergai) wetland ecosystem integrity landscape biodiversity

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

Secular Changes of Stature in Rural Children and Adolescents in China, 1985-2010

引用

Biomedical and Environmental sciences 2014年第8期27卷 573-581页

作者： CHEN Tian Jiao JI Cheng Ye Institute of Child and Adolescent Health School of Public Health Peking University Health Science Center

Objective To analyze and assess secular change in stature in rural children and adolescents in China from 1985 to 2010. Methods Data were obtained from the 6 rounds of the Chinese National Survey on student＇s Constitution and Health. The subjects enrolled in the study were children and adolescents aged 7-18 years in rural areas of provincial capitals. Results An overall positive secular trend in stature occurred in rural areas of provincial capitals in China from 1985 to 2010. The overall average increase rates were 3.1 and 2.4 cm/decade for boys and girls, respectively. The total body height increases for grown up boys and girls were 3.6 and 2.3 cm and the increase rates were 1.4 and 0.9 cm/decade, respectively. There were differences in body height increase among eastern, central and western regions. The average body height of the children or adolescents in eastern region was highest, followed by central region and western region. The overall increase rates in central region were highest among the three regions. The difference between eastern/central region and western region was obvious. 〈br〉 Conclusion Positive secular trend in stature of children or adolescents has occurred in rural area of China, and rural boys and girls showed a great potential for continuous growth. More attention should be paid to the differences in children＇s body height between western region and eastern/central region.

关键词： Secular change Stature Rural population Regional difference Child and adolescent

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

Biotechnological approaches in glucosinolate production

引用

Journal of Integrative Plant Biology 2018年第12期60卷 1231-1248页

作者： Annette Petersen Cuiwei Wang Christoph Crocoll Barbara Ann Halkier DynaMo center Copenhagen Plant Science Centre Department of Plant and Environmental Sciences University of Copenhagen

Glucosinolates(GLSs) are sulfur-rich, amino acid-derived defense compounds characteristic of the Brassicales order. In the past, GLSs were mostly known as anti-nutritional factors in fodder, biopesticides in agriculture, and flavors in condiments such as mustard. However, in recent times, GLSs have received increased attention as promoters of human *** has spurred intensive research towards generating rich sources of health-promoting GLSs. We provide a comprehensive overview of the biotechnologica approaches applied to reach this goal. This includes optimization of GLS production and composition in native, GLS-producing plants, including hairy root and cell cultures thereof, as well as synthetic biology approaches in heterologous hosts, such as tobacco and the microbial organisms Escherichia coli and Saccharomyces cerevisiae. The progress using these different approaches is discussed.

关键词： GLS Biotechnological approaches in glucosinolate production

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

Disagreement in middle ear volume estimation between tympanometry and three-dimensional volume reconstruction in the context of tympanic membrane perforation

引用

Journal of Otology 2017年第2期12卷 74-79页

作者： David J.Carpenter Debara L.Tucci David M.Kaylie Dennis O.Frank-Ito Division of Head and Neck Surgery&Communication sciences Department of SurgeryDuke University Medical CenterDurhamNCUSA Computational Biology&Bioinformatics phd Program Duke UniversityDurhamNCUSA Department of Mechanical Engineering and Materials science Duke UniversityDurhamNCUSA

Introduction: Middle ear volume(MEV) is a clinically relevant parameter across middle ear diseases. MEV values between these techniques have never before been tested for agreement in ears with perforated tympanic membranes(TMs).Methods: Middle ears were identified from 36 patients ranging 18-89 years of age with TM perforations who underwent tympanometry and temporal bone computed tomography(CT) between 2005 and 2015. MEVs calculated by both tympanometry and three-dimensional volume reconstruction(3DVR) were analyzed for agreement using Bland Altman plots. The differences between tympanometric and 3DVR MEV values for each given middle ear were characterized across MEV quartiles(1= smallest; 4= largest) and across increasing states of middle ear disease using Kruskale Wallis and Wilcoxon testing with Bonferroni ***: Bland Altman plots demonstrated significant disagreement between MEV measurement techniques. Differences between tympanometric(T) and 3DVR MEV values were significantly greater with increasing average(i.e.(Tt3DVR)/2)) MEV per linear regression(p < 0.0001). Significance was demonstrated between fourth and first average MEV quartiles(p= 0.0024), fourth and second quartiles(p= 0.0024), third and first quartiles(p= 0.0048), and third and second quartiles(p= 0.048). Absolute MEV difference was not significantly different across varying states of middle ear disease(p= 0.44).Conclusion: Statistically and clinically significant disagreement was demonstrated between tympanometric and 3DVR MEV values. Studies that vary in MEV estimation techniques may be expected to demonstrate significantly different results. These preliminary results suggest that clinicians should endeavor to seek further confirmation when interpreting high tympanometric MEV values.

关键词： Middle ear volume Tympanometry Three-dimensional volume reconstruction Tympanic membrane perforation

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

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：