检索结果-南通市图书馆

Effect of esculetin on bone metabolism in ovariectomized rats

在线全文

学校读者我要写书评

暂无评论

Journal of Traditional Chinese Medicine 2018年第6期38卷 896-903页

作者： liu Meijie Wang Ruihai Li Yan Bai Dong Pan Jinghua liu Hong Wang Shaojun Wu Jiaying Sun Gang Miao Qing Ju Dahong liu limei Bone and Joint Diseases Laboratory Experimental Research CenterChina Academy of Chinese Medicine Science 100700China The Basic Research Center of Recipe and Syndrome in Traditional Chinese Medicine Institute of Basic Theory for Chinese MedicineChina Academy of Chinese Medicine ScienceBeijing 100700China

OBJECTIVE: To determine the effect of an esculetin formulation(at 97.4% purity) on osteoporosis, and to investigate the potential underlying molecular mechanism(s).METHODS: Sixty specific pathogen free-grade female Wistar rats were randomly assigned to three groups: blank control(n = 12), sham(n = 12), and model(n = 36). The model group were bilaterally ovariectomized. The sham group had the tissue surrounding the ovaries removed, while the ovaries were retained. After 3 months, the model group was randomly divided into three subgroups: OVX(n = 12), positive control(n = 12), and esculetin(n =12). The positive control group and the esculetin group were intragastrically administered diethylstilbestrol(0.046 mgkd^(-1)), respec·kg^(-1)tively,·d^(-1)) or esculetin(384 mgg^(-1) once per day for 6 consecu··-tive days; medication administration was then stopped for 1 d, before being administered for another 6 consecutive days. All rats were treated for 3months. Samples were collected at the end of the treatment period. An Osteocore3 Digital 2D bone densitometer was used to test the bone mineral density, and histomorphometric analysis was performed to measure bone mass, bone formation,and bone resorption. Enzyme-linked immunosorbent assay analysis was used to measure the serum concentrations of interleukin-6(IL-6), osteoprotegerin(OPG), and receptor activator of nuclear factor-kappa B ligand(RANKL). Immunohistochemistry and in situ hybridization were performed to detect the protein and mRNA expressions of OPG and RANKL in osteoblasts and bone marrow stromal ***: Compared with the OVX group, the esculetin group had significantly greater femoral bone mineral density and tibial trabecular bone volume,and significantly smaller trabecular resorption surface. The percentage of trabecular formation surface, average osteoid width, trabecular bone mineralization rate, and cortical bone mineralization rate did not significantly differ between groups. Compared with the sham g

关键词： Esculetin Osteoporosis Osteoprotegerin RANK ligand Bone resorption

Environmental benefits and farmers' adoption of winter cover crops in the North China Plain

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2024年第1期34卷 159-169页

作者： Shufang GUO Yitao ZHANG limei ZHAI Jian liu Hongyuan WANG Hongbin liu State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China Key Laboratory of Nonpoint Source Pollution ControlMinistry of Agriculture and Rural AffairsInstitute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Institute of Agricultural Environment and Resources Yunnan Academy of Agricultural SciencesKunming 650205China Shandong Yucheng Agro-ecosystem National Observation Research Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China The Norwegian Institute of Bioeconomy Research(NIBIO) Akershus 1431Norway

The introduction of cover crops into monoculture systems to improve soil health has been widely adopted worldwide. However, little is known about the environmental risks and application prospects of different cover crops in spring maize(Zea mays L.) monocultures proposed in the North China Plain. A pot experiment was conducted to evaluate the effects of different winter cover crops on subsequent maize yield, soil fertility, and environmental risks of nitrogen(N) loss, and a questionnaire survey was conducted to examine factors influencing farmers' willingness to adopt cover crops in the North China Plain. Based on the same fertilization regime during the maize growing period, four winter cover crop treatments were set up, including bare fallow, hairy vetch(Vicia villosa Roth.), February orchid(Orychophragmus violaceus), and winter oilseed rape(Brassica campestris L.). The results indicated that winter cover crops significantly increased subsequent maize yield and soil organic carbon, total N, and microbial biomass carbon and N compared with the bare fallow *** incorporation of cover crops led to a negligible increase in nitrous oxide(N_(2)O) emissions and had a very limited effect on ammonia(NH_(3)) *** incorporation of February orchid and winter oilseed rape decreased nitrate leaching compared with the hairy vetch treatment in the maize growing *** N losses via N_(2)O and NH_(3) emissions and N leaching accounted for 71%–84% of the N surplus. However, yield increase and environmental benefits were not the main positive factors for farmers to accept cover crops. Financial incentive was rated by 83.9% of farmers as an “extremely important” factor, followed by other costs, when considering winter cover cropping. These results indicate that the environmental benefits depend on the type of cover crop. Maintaining high levels of soil fertility and maize yield, providing sufficient subsidies, and encouraging large-area cultivation of cover crops

关键词： cover crop N leaching NH_(3)emission N_(2)O emission spring maize willingness to accept

G-四链体结构与DNA甲基化修饰的交互影响:当前研究与未来展望

在线全文

学校读者我要写书评

暂无评论

化学通报 2024年第9期87卷 1098-1106页

作者：周鑫辰张卓董姝含靳茁战星彤王鹤霖杨舒惠刘丽梅北华大学医学技术学院微生物学检验教研室吉林市132013

基因表达调控是生物学中复杂而关键的过程,涉及细胞内外多因素及DNA结构构成。DNA双螺旋是基本形式,但非规范DNA结构如G-四链体(G4)在基因组关键区域中广泛存在,参与调节基因表达、维持染色体稳定性和影响端粒伸长。G4同时存在于DNA和RN... 详细信息

基因表达调控是生物学中复杂而关键的过程,涉及细胞内外多因素及DNA结构构成。DNA双螺旋是基本形式,但非规范DNA结构如G-四链体(G4)在基因组关键区域中广泛存在,参与调节基因表达、维持染色体稳定性和影响端粒伸长。G4同时存在于DNA和RNA中,与基因表达调控密切相关。DNA甲基化是表观遗传标记,近年研究发现其与多种疾病关联,影响细胞功能。本文综述G4与DNA甲基化的关系,特别在CpG(Cytosine-phosphate-Guanine)岛区域的相互影响,为相关疾病的预防和治疗提供新策略。

关键词： G-四链体 DNA甲基化 CpG岛 DNA复制染色质结构状态

Entrapment of Inclusions in Diamond Crystals Grown from Fe-Ni-C System

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2002年第2期18卷 171-172页

作者： Yuxian liu, limei XIAO and Longwei YINCollege of Materials Science and Engineering, Shandong University, Jinan 250061, China [ Manuscript received June 28, 2001, in revised form October 18, 2001] Coll. of Mat. Sci. and Eng. Shandong Univ. Jinan 250061 China

Diamond single crystals grown from Fe-Ni-C system at high temperature-high pressure (HPHT) usually contain inclusions related to the metallic catalyst. During the diamond growth, the metallic inclusions are trapped by the growth front or are formed through reaction between the contaminants trapped in the diamond. In the present paper, the metallic inclusions related to the catalyst were systematically examined by transmission electron microscopy (TEM). The chemical composition and crystal structure of the metallic inclusions were for the first time determined by selected area electron diffraction pattern (SADP) combined with energy dispersive X-ray spectrometry (EDS). It is shown that the inclusions are mainly composed of orthorhombic FeSi2, fcc (FeNi)23C6, and orthorhombic Fe3C, hexagonal Ni3C.

关键词： Synthetic diamond Fe-Ni-C system Inclusion Transmission electron microscopy

基于土壤微生物群落结构的参地土壤改良研究进展

在线全文

学校读者我要写书评

暂无评论

北华大学学报（自然科学版） 2024年第4期25卷 442-447页

作者：孙晓红徐增鑫鲍双双刘丽梅李洪涛北华大学基础医学院吉林吉林132013 北华大学医学技术学院吉林吉林132013

改良参地土壤是缓解参地资源紧缺、促进人参种植业健康持续发展的有效途径。综述土壤微生物群落结构改变与连作障碍关系,参地土壤化学消毒、农业改良和微生物防治对土壤微生物的影响。结果显示:微生物制剂可以通过调整土壤微生物群落结... 详细信息

改良参地土壤是缓解参地资源紧缺、促进人参种植业健康持续发展的有效途径。综述土壤微生物群落结构改变与连作障碍关系,参地土壤化学消毒、农业改良和微生物防治对土壤微生物的影响。结果显示:微生物制剂可以通过调整土壤微生物群落结构、拮抗病原菌、激活养分等有效防治人参病害及改良参地土壤;开发高效、具有广谱抑菌活性的微生物混合菌剂,辅以化学消毒、农业改良等土壤改良技术是改良参地土壤及防治人参病害的关键。

关键词：人参参地微生物群落结构连作障碍土壤改良

Process design and intensification of multicomponent azeotropes special distillation separation via molecular simulation and system optimization

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第7期71卷 24-44页

作者： Chunliang liu Jianhui Zhong Ranran Wei Jiuxu Ruan Kaicong Wang Zhaoyou Zhu Yinglong Wang limei Zhong College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China

This work provides an overview of distillation processes,including process design for different distillation processes,selection of entrainers for special distillation processes,system integration and intensification of distillation processes,optimization of process parameters for distillation processes and recent research progress in dynamic control ***,the feasibility of using thermodynamic topological theories such as residual curve,phase equilibrium line and distillation boundary line to analyze different separation regions is discussed,and the rationality of distillation process design is discussed by using its ***,the application of molecular simulation methods such as molecular dynamics simulation and quantum chemical calculation in the screening of entrainer is discussed for the extractive distillation *** thermal coupling mechanism of different distillation processes is used to explore the process of different process ***,a mixed integer nonlinear optimization strategy for the distillation process based on different algorithms is ***,the improvement of dynamic control strategies for different distillation processes in recent years is *** work focuses on the application of process intensification and system optimization in the design of distillation process,and analyzes the challenges,prospects,and development trends of distillation technology in the separation of multicomponent azeotropes.

关键词： Azeotrope separation Process design Optimization algorithm Process integration Dynamic control Entrainer selection

Microstructure and wear resistance of PTA clad Cr7C3/γ-Fe ceramal composite coating

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第8期16卷 874-878页

作者： liu Junbo, WANG limei and HUANG Jihua (Weifang University, Weifang 261061, China School of Materials Science and Engineering, University of Science and Technology, Beijing 100083, China) Weifang University Weifang 261061 China. School of Materials Science and Engineering University of Science and Technology Beijing 100083 China

A wear resistant Cr7C3/γ-Fe ceramal composite coating was fabricated on substrate of the hardening and tempering C degree steel by PTA (plasma transferred arc) cladding with (wt%) Fe-25Cr-7C elemental powder blends. Microstructure of the coating was characterized by OM, SEM, XRD and EDS. Wear resistance of the coating was tested under dry sliding wear condition at room temperature. The results indicate that the PTA clad ceramal composite coating has a rapidly solidified fine microstructure consisting of Cr7C3 primary particles uniformly distributed in theγ-Fe matrix and is metallurgically bonded to the C degree steel substrate. The PTA clad Cr7C3/γ-Fe ceramal composite coating has high hardness and excellent wear resistance under dry sliding wear test conditions. The excellent wear resistance of the Cr7C3/γ-Fe ceramal composite coating is attributed to the coating's high hardness, strong covalent atomic bonding and refined microstructure.

关键词： PTA clad Cr7C3/γ-Fe composite coating microstructure wear resistance.

Intelligent Predictive Analysis of the Performance Level of Discipline Construction in Local Universities Based on Grey Prediction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Intelligent Predictive Analysis of the Performance Level of ...

Enhanced Cooling Efficiency of Urban Trees on Hotter Summer Days in 70 Cities of China

作者： limei liu Xiuling Li School of Applied Mathematics Jilin University of Finance and Economics

In order to overcome the difficulties in measurement data collecting of the performance level of discipline construction in local universities,GM（1,1） grey prediction model was used to predict and analyze the performance level of discipline construction in local universities,which combined with the general performance indicator system of discipline *** research shows that to improve the performance level of discipline construction,we must strengthen the construction of teaching staff,ensure sufficient and high-quality teaching resources,optimize the process of personnel training,promote the development of students,strengthen quality supervision and guarantee,enhance the scientific research ability and awareness of teachers and students,clarify the orientation and goals of universities and actively promote the economic and social development of the country and the region.

关键词： Discipline Construction Local Universities Performance Level Grey Prediction Intelligent Prediction

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

Advances in Atmospheric Sciences 2024年第11期41卷 2259-2275页

作者： limei YANG Jun GE Yipeng CAO Yu liu Xing LUO Shiyao WANG Weidong GUO School of Atmospheric Sciences Nanjing UniversityNanjing 210023China Joint International Research Laboratory of Atmospheric and Earth System Sciences Nanjing UniversityNanjing 210023China Frontiers Science Center for Critical Earth Material Cycling Nanjing UniversityNanjing 210023China

Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter days, depending on the physiological response of urban trees to rising ambient temperature. However, the response of urban trees' cooling efficiency to rising urban temperature remains poorly quantified for China's cities. In this study, we quantify the response of urban trees' cooling efficiency to rising urban temperature at noontime [~1330 LT(local time), LT=UTC+8] in 17summers(June, July, and August) from 2003–19 in 70 economically developed cities of China based on satellite observations. The results show that urban trees have stronger cooling efficiency with increasing temperature, suggesting additional cooling benefits provided by urban trees on hotter days. The enhanced cooling efficiency values of urban trees range from 0.002 to 0.055℃ %-1 per 1℃ increase in temperature across the selected cities, with larger values for the lowTCP-level cities. The response is also regulated by background temperature and precipitation, as the additional cooling benefit tends to be larger in warmer and wetter cities at the same TCP level. The positive response of urban trees' cooling efficiency to rising urban temperature is explained mainly by the stronger evapotranspiration of urban trees on hotter *** results have important implications for alleviating urban heat risk by utilizing urban trees, particularly considering that extreme hot days are becoming more frequent in cities under global warming.

关键词： urban trees cooling efficiency China's cities evapotranspiration summer hot days