检索结果-南通市图书馆

Report on Childhood Obesity in China (5) Body Weight, Body Dissatisfaction, and Depression Symptoms of Chinese Children Aged 9-10 Years

引用

Biomedical and Environmental Sciences 2007年第1期20卷 11-18页

作者： YAN-PING LI GUAN-SHENG MA EVERT G. SCHOUTEN XIAO-QI HU ZHAO-HUI CUI DONG WANG frans j. kok National Institute for Nutrition and Food Safety Chinese Center for Disease Control and Prevention 29 Nanwei Road Beijing 100050 China Division of Human Nutrition Wageningen University The Netherlands

Obj.ctive To investigate the relationship between body weight, body dissatisfaction and depression symptoms among Chinese children. Methods The fasting body weight and height of the third and fourth grade students （n=3886, aged 9 or 10 years） from 20 schools in Beij.ng, China, were measured, and the students were asked to choose the figures of body image and to complete the self-reported children＇s depression inventory （CDI） questionnaire. Results The CDI Cronbach＇s alpha was 0.81. The total CDI score was 9.60±7.50, 13.2% of children （boys 16.7% vs girls 9.5%） were at risk of developing depression symptoms. Overweight girls, but not boys, had significantly higher total CDI score than their normal weight counteparts. Both obese girls and boys showed a higher negative self-esteem score. More than one fifth underweight girls still wanted to be thinner while more than one third obese boys still wanted to be heavier. Children who wanted to be thinner showed slightly higher scores of ineffectiveness and negative self-esteem. After introducing the body dissatisfaction into the model, overweight was still associated with total CDI score among girls and obesity was still associated with negative self-esteem among both boys and girls. Conclusion Overweight girls show a significantly higher depression symptom score than their normal weight counterparts, which maybe partially explained by body dissatisfaction. Obese boys and girls are both more likely to suffer from low self-esteem, which is partially explained by body dissatisfaction.

关键词： Depression symptoms Body dissatisfaction Overweight Children

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

Fe_(3)O_(4)对黄铜矿在酸性硫酸铁溶液中铜溶解氧化还原反应的影响

引用

Transactions of Nonferrous Metals Society of China 2024年第6期34卷 1965-1975页

作者： Kolela j.NYEMBWE Elvis FOSSO-KANKEU frans WAANDERS Martin MKANDAWIRE Didier K NYEMBWE Bhekie B MAMBA Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals EngineeringFaculty of EngineeringNorth-West UniversityPotchefstroomSouth Africa Department of Mining Engineering College of Science Engineering and TechnologyUniversity of South AfricaFlorida Science CampusJohannesburgSouth Africa Department of Metallurgy Faculty of Engineering and Built EnvironmentUniversity of JohannesburgDoornfonteinJohannesburgSouth Africa Department of Chemistry School of Science and TechnologyCape Breton UniversityCanada School of Mining Metallurgy and Chemical EngineeringFaculty of Engineering and the Built EnvironmentUniversity of JohannesburgJohannesburgSouth Africa Institute for Nanotechnology and Water Sustainability College of Science Engineering and TechnologyUniversity of South AfricaFlorida Science CampusJohannesburgSouth Africa

由于钝化层的形成,黄铜矿(CuFeS_(2))在氧化条件下浸出通常具有溶解速率缓慢的特点。为了将黄铜矿浸出过程中的钝化效应降至最低并提高铜的回收率,研究了CuFeS_(2)在不同pH值(1.0、1.5和1.8)和温度(25和50℃)条件下浸出时,向Fe_(2)(SO_(... 详细信息

由于钝化层的形成,黄铜矿(CuFeS_(2))在氧化条件下浸出通常具有溶解速率缓慢的特点。为了将黄铜矿浸出过程中的钝化效应降至最低并提高铜的回收率,研究了CuFeS_(2)在不同pH值(1.0、1.5和1.8)和温度(25和50℃)条件下浸出时,向Fe_(2)(SO_(4))_(3)−H_(2)SO_(4)浸出剂中添加磁铁矿(Fe_(3)O_(4))对铜溶解速率的影响。结果表明,溶液pH值、电位和温度在溶解过程中起着关键作用。在pH 1.8、50℃和400 mV的条件下,Fe_(3)O_(4)−CuFeS_(2)混合体系中铜的回收率达到最大值(70%),而未添加Fe_(3)O_(4)时,CuFeS_(2)中铜的回收率较低(48%)。添加Fe_(3)O_(4)有助于维持较高的氧化还原值。添加Fe_(3)O_(4)还使活化能从79.04 kj.mol降低到53.69 kj.mol。这表明,当Fe_(3)O_(4)存在时,由于形成了更易溶解的中间体斑铜矿(Cu_(5)FeS_(4))和辉铜矿(Cu_(2)S),CuFeS_(2)更易被氧化。两种溶解过程都受到矿物表面的化学控制。此外,对浸出残渣的矿物学分析表明,当无Fe_(3)O_(4)存在时,作为表面钝化物的黄钾铁矾浓度较高。因此,添加Fe_(3)O_(4)减少了钝化层的形成,提升了铜的回收率。

关键词：黄铜矿溶解磁铁矿电偶钝化

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

Nitridation of Ni-based alloys:thermodynamics,kinetics,and deformation phenomena accompanying internal precipitation

引用

Rare Metals 2006年第5期25卷 501-511页

作者： Alexander A.Kodentsov j.rma K.Kivilahti frans j.j.van Loo Laboratory of Materials and Interface Chemistry Eindhoven University of TechnologyP.O.Box 5135600 MBEindhovenThe Netherlands Laboratory of Electronics Production Technology Helsinki University of TechnologyFIN-02150 EspooFinland

When a moderately stable phase is precipitated out during an intemal reaction, the behaviour of the penetrating atoms within the diffusion zone can be interpreted based on thermodynamic considerations. Evidence for “up-hill” diffusion of the penetrating species through the matrix towards the precipitation front during the intemal nitridation of Ni-Cr alloys at 1125℃ and 6000 bar of N2-pressure was predicted. Such behaviour of nitrogen is opposite to the boundary conditions in Wagner＇s description of internal reactions. A volume change associated with the precipitation reaction resulted in a stress gradient between the alloys surface and the intemal nitridation front. Stress relief occurred mainly by transport of nickel to the gas/metal interface. Pipe diffusion-controlled creep is the dominant stress accommodation mechanism during nitriding of dilute Ni-Cr alloys at 700℃ under a flowing NH3 ＋ H2 gas mixture.

关键词： nitridation nickel alloys thermodynamics diffusion internal precipitation

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

Structural, compositional and mineralogical characterization of carbonatitic copper sulfide: Run of mine, concentrate and tailings

引用

International j.urnal of Minerals,Metallurgy and Materials 2019年第2期26卷 143-151页

作者： Kolela j.Nyembwe Elvis Fosso-Kankeu frans Waanders Kasongo D Nyembwe Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals Engineering Faculty of Engineering North-West University School of Mining Metallurgy and Chemical Engineering Faculty of Engineering and the Built Environment University of Johannesburg

The aim of this study was to determine the structural, compositional, and mineralogical composition of carbonatitic copper sulfide concentrator plant streams. Three samples, each from a different stream(run of mine(ROM), concentrate, and tailings) of a copper concentrator were characterized using various techniques, including stereomicroscopy, X-ray fluorescence, X-ray diffraction, Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy(SEM) in conj.nction with energy-dispersive X-ray spectroscopy(EDS), and optical microscopy. The results reveal that each stream possesses its own unique compositional features. Carbonate minerals associated with calcite and dolomite, followed by quartz, remain the maj.r minerals in both the ROM and tails streams. In the ROM stream, chalcopyrite appears to occur as veins within the carbonatite-hosting ore body. Mineral phase mutation was discovered in the tails stream because magnetite formerly identified in the ROM as the primary iron oxide had evolved into hematite. This metamorphosis was likely promoted by the concentration process. The concentration process was effective, upgrading the chalcopyrite content from 2 wt% in the ROM stream to 58 wt% in the concentrate stream; it was accompanied by bornite(4 wt%), anilite(3 wt%), and digenite(2.5 wt%). In addition, the concentrate stream exhibited properties distinctive from those of the other streams. The FTIR analysis showed the existence of a sulfide group related to the chalcopyrite mineral. Free chalcopyrite grains were observed in the concentrate by SEM analysis, and their mineral presence was supported by the EDS analysis results. All characterization techniques corresponded well with each other regarding the structure, chemistry, and composition of the samples.

关键词： chalcopyrite mineral characterization phase mutation concentrate streams

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

Report on Childhood Obesity in China(8):Effects and Sustainability of Physical Activity Intervention on Body Composition of Chinese Youth

引用

Biomedical and Environmental Sciences 2010年第3期23卷 180-187页

作者： YAN-PING LI XIAO=QI HU EVERT G. SCHOUTEN AI-LING LIU SONG-MING DU LIN-ZHONG LI ZHAO-HuI CUI DONG WANG frans j.kok FRANK B HU GUAN-SHENG MA National Institute for Nutrition and Food Safety Chinese Center for Disease Control and Prevention Beijing 100050 China Division of Human Nutrition Wageningen University The Netherlands Departments of Nutrition and Epidemiology Harvard School of Public Health USA Department of Global Health and Population Harvard School of Public Health USA

Obj.ctives To determine whether a large-scale physical activity intervention could affect body composition in primary school students in Beij.ng, China. Methods The study design was one-year cluster randomized controlled trial of physical activity intervention （20 rain of daily exercise in the classroom） with an additional year of follow-up among 4 700 students aged 8-11 years at baseline. Results After the one-year intervention, BMI increased by 0.56 kg/m2 （SD 1.15） in the intervention group and by 0.72 kg/m^2 （SD 1.20） in the control group, with a mean difference of-0.15 kg/m^2 （95% CI： -0.28 to -0.02）. BMI z score decreased by -0.05 （SD 0.44） in the intervention group, but increased by 0.01 （SD 0.46） in the control group, with a mean difference of-0.07 （-0.13 to -0.01）. After another year of follow up, compared to the control group, children in the intervention group had significantly lower BMI （-0.13, -0.25 to -0.01 ）, BMI z score （-0.05, -0.10 to -0.01）, fat mass （-0.27 kg, -0.53 to -0.02） and percent body fat （-0.53, -1.00 to -0.05）. The intervention had a more pronounced effect on weight, height, BMI, BMI z score, and body composition among obese children than among normal weight or overweight children. Compared to the control group, the intervention group had a significantly higher percentage of children who maintained or reduced their BMI z score at year 1 （P-0.008） and year 2 （P=-0.04）. Conclusions These findings suggest that 20 min of daily moderate to vigorous physical activity during the school year is a feasible and effective way to prevent excessive gain of body weight, BMI, and body fatness in primary school students.

关键词： Intervention BMI School China

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

Design and Optimization of a GaN GIT Based PFC Boost Converter

引用

Chinese j.urnal of Electrical Engineering 2017年第3期3卷 34-43页

作者： Wenbo Wang frans Pansier j.lena Popovic j.A.Ferreira Delft University of Technology DelftThe Netherlands

The advent of GaN power devices brings the possibility of pushing up frequencies of power electronics system beyond the capacity of conventional Si *** harvest the high frequency operation benefits of GaN technology,not only GaN devices should be used optimally by providing proper switching and conduction conditions to best accommodate parasitic elements inherent with the devices,other components should also be capable of facilitating high frequency *** this paper,PFC boost converter is used as a platform to harvest the benefits of GaN technology and,at the same time,to uncover the limitations in pushing power electronics systems up.A 600W PFC boost converter with a maximum switching frequency of 3MHz is designed and implemented,which reached an average efficiency of 98.5%.The results indicate that,when properly used,a GaN PFC boost converter could operate at a frequency that is beyond the reach of conventional Si *** well,with availability of GaN devices,high frequency operation of power electronics systems is no longer limited by the lack of switching devices but by practical issues *** frequency magnetic materials,high frequency controllers,etc.

关键词： GaN GIT boost converter PFC high frequency design optimization

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

Association of smoking, alcohol drinking and dietary factors with esophageal cancer in high- and low-risk areas of j.angsu Province, China

引用

World j.urnal of Gastroenterology 2006年第11期12卷 1686-1693页

作者： Ming Wu j.n-Kou Zhao Xiao-Shu Hu Pei-Hua Wang Yu Qin Yin-Chang Lu j.e Yang Ai-Min Liu De-Lin Wu Zuo-Feng Zhang kok j.frans Pieter van't Veer j.angsu Provincial Center for Disease Control and Prevention Nanjing 210009 Jiangsu ProvinceChina Dafeng Center for Disease Control and Prevention Dafeng 224100 Jiangsu Province China Ganyu Center for Disease Control and Prevention Ganyu 222100 Jiangsu Province China Department of Epidemiology UCLA School of PublicHealth Los Angeles California United States Pieter van't Veer Division of Human Nutrition Wageningen University Wageningen 6700 EV the Netherlands Supported by Jiangsu Provincial Health Department No. RC 2003090

AIM： To study the main environmental and lifestyle factors that account for the regional differences in esophageal cancer （EC） risk in low- and high-risk areas of j.angsu Province, China. METHODS： Since 2003, a population-based casecontrol study has been conducted simultaneously in lowrisk （Ganyu County） and high-risk （Dafeng County） areas of j.angsu Province, China. Using identical protocols and pre-tested standardized questionnaire, following written informed consent, eligible subj.cts were inquired about their detail information on potential determinants of EC, including demographic information, socio-economic status, living conditions, disease history, family cancer history, smoking, alcohol drinking, dietary habits, frequency, amount of food intake, etc. Conditional logistic regression with maximum likelihood estimation was used to obtain Odds ratio （OR） and 95 % confidence interval （95% CI）, after adj.stment for potential confounders. RESULTS： In the preliminary analysis of the ongoing study, we recruited 291 pairs of cases and controls in Dafeng and 240 pairs of cases and controls in Ganyu, respectively. In both low-risk and high-risk areas, EC was inversely associated with socio-economic status, such as level of education, past economic status and body mass index. However, this disease was more frequent among those who had a family history of cancer or encountered misfortune in the past 10 years. EC was also more frequent among smokers, alcohol drinkers and fast eaters. Furthermore, there was a geographic variation of the associations between smoking, alcohol drinking and EC risk despite the similar prevalence of these risk factors in both low-risk and high-risk areas. The dose-response relationship of smoking and smoking related variables, such as age of the first smoking, duration and amount were apparent only in high-risk areas. On the contrary, a dose-response relationship on the effect of alcohol drinking on EC was observed only in low-risk areas. CONCL

关键词： Esophageal cacner Case-control study Smoking Alcohol drinking Dietary factors

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

Evolutionary dynamics of leucine‐rich repeat receptor‐like kinases and related genes in plants:A phylogenomic approach

引用

j.urnal of Integrative Plant Biology 2014年第7期56卷 648-662页

作者： Tao Shi Hongwen Huang Michael j.Sanderson frans E.Tax Department of Ecology and Evolutionary Biology University of Arizona School of Life Sciences Lanzhou University South China Botanical Garden the Chinese Academy of Sciences Department of Molecular and Cellular Biology University of Arizona School of Plant Sciences University of Arizona

Leucine-rich repeat （LRR） receptor-like kinases （RLKs）, evolutionarily related LRR receptor-like proteins （RLPs） and receptor-like cytoplasmic kinases （RLCKs） have important roles in plant signaling, and their gene subfamilies are large with a complicated history of gene duplication and loss. In three pairs of closely related lineages, including Arabidopsis thaliana and A. lyrata （Arabidopsis）, Lotus j.ponicus, and Medicago truncatula （Legumes）, Oryza sativa ssp. j.ponica, and O. sativa ssp. indica （Rice）, we find that LRR RLKs comprise the largest group of these LRR-related subfamilies, while the related RLCKs represent the smal est group. In addition, comparison of orthologs indicates a high frequency of reciprocal gene loss of the LRR RLK/LRR RLP/RLCK subfamilies. Furthermore, pairwise comparisons show that reciprocal gene loss is often associated with lineage-specific duplication（s） in the alternative lineage. Last, analysis of genes in A. thaliana involved in development revealed that most are highly conserved orthologs without species-specific duplication in the two Arabidopsis species and originated from older Arabidopsis-specific or rosid-specific duplications. We discuss＆amp;nbsp;potential pitfal s related to functional prediction for genes that have undergone frequent turnover （duplications, losses, and domain architecture changes）, and conclude that prediction based on phylogenetic relationships wil likely outperform that based on sequence similarity alone.

关键词： Domain architecture evolution gene duplication and loss leucine-rich repeat receptor-like kinases leucine-rich repeat receptor-like proteins receptor-like cytoplasmic kinases

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

“Biological Nitrogen Fixation” Book Summary

引用

Advances in Microbiology 2016年第6期6卷 407-411页

作者： frans j. de Bruij. INRA/CNRS Laboratory of Plant-Microbe Interactions Castanet France

Biological nitrogen fixation is a very valuable alternative to nitrogen fertilizer. This process will be discussed in the “Biological Nitrogen Fixation” book. A wide array of free-living and associative nitrogen fixing organisms (diazotrophs) will be covered. The most extensively studied and applied example of biological nitrogen fixation is the symbiotic interaction between nitrogen fixing “rhizobia” and legume plants. While legumes are important as maj.r food and feed crops, cereals such as wheat, maize and rice are the primary food crops, but do not have this symbiotic nitrogen fixing interaction with rhizobia. It has thus been a “holy grail” to transfer the ability to fix nitrogen to the cereals and this topic will be also addressed in these books.

关键词： Biological Nitrogen Fixation Diazotrophs Nodulation Nitrogenase Legumes Cereals

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

Reducing potassium deficiency by using sodium fertilisation

引用

Stress Biology 2022年第1期2卷 151-160页

作者： Sarah j.Thorne frans j.M.Maathuis Department of Biology University of SheffieldSheffield S102TNUK Department of Biology University of YorkYork YO15DDUK

Potassium(K)is the most abundant cation in the vast maj.rity of *** is required in large quantities which,in an agronomic context,typically necessitates application of K in the form of potash or other K ***,the price of K fertiliser has risen dramatically,a situation that is paralleled by increasing K deficiency of soils around the globe.A potential solution to this problem is to reduce crop K fertiliser dependency by replacing it with sodium(Na)fertiliser which carries a much smaller price *** this paper we discuss the physiological roles of K and Na and the implications of Na fertilisation for crop cultivation and soil *** using greenhouse growth assays we show distinct growth promotion after Na fertilisation in wheat,tomato,oilseed and *** results also show that up to 60%of tissue K can be substituted by Na without growth *** on these data,simple economic models suggest that(part)replacement of K fertiliser with Na fertiliser leads to considerable savings.

关键词： Deficiency Fertiliser Nutrient Potassium Salinity Sodium

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：