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Molecular basis of cryptorchidism-induced infertility

Science china(life sciences) 2010年第11期53卷 1274-1283页

作者： liU YiXun & li XiXia State Key Laboratory of Reproductive Biology, Institute of Zoology, chinese academy of sciences, beijing 100101, china State Key Laboratory of Reproductive Biology Institute of Zoology Chinese Academy of Sciences Beijing China

Artificial cryptorchidism or local testicular heat treatment can induce reversible oligospermia or azoospermia in monkeys and rats via germ cell apoptosis. Local warming of monkey testes in water at 43°C for 2 consecutive days (30 min per day) decreased the number of sperm in the semen by up to 80% on d 28, and the effect was completely reversed on d 144. Germ cells rely heavily on Sertoli cells for structural and nutritional support. Specialized junctions that play a pivotal role in spermatogenesis occur at sites of Sertoli-Sertoli and Sertoli-germ cell contact in the seminiferous epithelium. We demonstrated that expression of tight junction (TJ)-associated molecules, such as occludin and zonula occludens-1 (ZO-1), were greatly reduced 24–48 h after heat treatment, while the permeability of the blood-testis barrier (BTB) was simultaneously increased, but recovered 10 d later. These results indicate a reversible disruption of the BTB associated with transient inductions of transforming growth factor (TGF) β2 and β3 expression, p38 mitogen-activated protein kinase and extracellular signal-regulated kinase activation, and concomitant loss of occludin and ZO-1. This suggests that expression of TJ-associated molecules and the BTB was reversibly perturbed by mild testicular hyperthermia, and that the heat-induced induction of TGF-β might be involved in downregulating TJ-associated proteins, leading to cell junction reduction. This review discusses the changes in total gene expression patterns after experimental cryptorchidism in adult mouse testes, and the cloning of several novel, physiologically significant spermatogenesis-specific genes.

关键词： cryptorchidism spermatogenesis apoptosis heat stress Sertoli cells blood-testis barrier tight junction

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Strict constraints on 2D primitive pairs for engineering symbol recognition:Theory and application

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Science china(Information sciences) 2012年第5期55卷 1032-1041页

作者： li Ting 1,2,QIU XianJie 1,HUANG He 1 & WANG ZhaoQi 1 1 Virtual Reality Laboratory,Institute of Computing Technology chinese academy of sciences,beijing 100190,china 2 Graduate University of chinese academy of sciences,beijing 100049,china Virtual Reality Laboratory Institute of Computing Technology Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

Geometric constraints on the line-line pair,line-arc pair and arcarc pair are *** con-straints are able to encode the geometric relations between lines,arcs and circles.A geometric proof is presented to demonstrate that the constraints are stable under translation,rotation,uniform scaling or reflection of the primitive *** on the constraints,an algorithm for recognizing symbols in drawings is ***-perimental results show that,compared with three other methods,our method can distinguish more primitive pairs and has higher accuracy in engineering symbol recognition.

关键词： coordinated multi-point transmission multicell cooperation capacity analysis MIMO-OFDM power allocation frequency selective MIMO channel

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Thermal stability of oxygen evolution in photosystem Ⅱ core complex in the presence of digalactosyl diacylglycerol

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chinese Science Bulletin 2002年第24期47卷 2089-2092页

作者： YANG Zhenle, li liangbi & KUANG TingyunPhotosynthesis Research Center, Institute of Botany, chinese academy of sciences, beijing 100093, china Photosynthesis Research Center Institute of Botany Chinese Academy of Sciences Beijing China

The influence of digalactosyldiacylglycerol (DGDG), one of the photosynthetic membrane lipids, on heat inactivation of the process of oxygen evolution has been studied in vitro in photosystem Ⅱ(PS Ⅱ) core complex. It was found that the temperature of semi-inactivation of oxygen evolution in the complex increased from 40.0 to about 43.0℃ in the presence of DGDG with 5-min heat treatment in the dark. Furthermore, when PS Ⅱ core complex was incubated for 5 min at 45.0℃, the oxygen evolution in the complex was completely lost, whilst the DGDG-complexed PS Ⅱ core complex still retained a 16% of activity (100% for 25.0℃). In addition, a 1-h incubation at 38.0℃ inactivated absolutely the oxygen evolution for the PS Ⅱ core complex. By contrast, there remained about 20% of activity (zero time for 100%) for the complex in the presence of DGDG under the same condition. These results indicate a new role of DGDG in the protection of PS Ⅱ core complex against the deleterious effects of temperature. It was

关键词： digalactosyl diacylglycerol photosystem Ⅱ core complex extrinsic protein of 33 kD thermal stability oxygen evolution.

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KoreainvestedenterprisesandthedevelopmentofWeihai

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Journal of Geographical sciences 1998年第2期8卷 28-38页

作者： li WenyanInstitute of Geography, chinese academy of sciences, beijing 100101 china

with the implementation of opendoor policy of the ***, Shandong's coastal area, relying on its advantageous location and abundant resources, has become one of the most rapidly developing areas in northern china for ten years or so. In the process of the development of Weihai, Koreainvested enterprises have been playing a more and more important role. Taking Weihai as an example, this paper attempts to make a preliminary study mainly on the relationship between the Korean direct investment and the economic development in china's port cities concerned.

关键词： Koreainvested enterprises sustainable development Weihai china.

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chinese national clinical practice guidelines on the prevention,diagnosis,and treatment of early gastric cancer

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chinese Medical Journal 2024年第8期137卷 887-908页

作者： Peng li Ziyu li Enqiang linghu Jiafu Ji Society of Digestive Endoscopy of the chinese Medical Association Colorectal Surgery Group of the chinese Medical Association chinese Association of Gastroenterologists&Hepatologists National Clinical Research Center for Digestive Diseases chinese Medical Journal Clinical Practice Guideline Collaborative Department of Gastroenterology Beijing Friendship HospitalCapital Medical UniversityNational Clinical Research Center for Digestive DiseaseBeijing 100050China Department of Gastrointestinal Surgery Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education)Peking University Cancer Hospital and InstituteBeijing 100142China Department of Gastroenterology and Hepatology the First Medical CenterChinese People’s Liberation Army General HospitalBeijing 100853China 不详

Background:Gastric cancer is one of the most common malignant tumors in the digestive system in *** comprehensive practice guidelines for early gastric cancer in china are currently ***,we created the chinese national clinical practice guideline for the prevention,diagnosis,and treatment of early gastric ***:This clinical practice guideline(CPG)was developed in accordance with the World Health Organization’s recommended process and with the Grading of Recommendations Assessment,Development,and Evaluation(GRADE)in assessing evidence *** used the Evidence to Decision framework to formulate clinical recommendations to minimize bias and increase transparency in the CPG development *** used the Reporting Items for practice Guidelines in HealThcare(RIGHT)statement and the Appraisal of Guidelines for Research and Evaluation II(AGREE II)as reporting and conduct guidelines to ensure completeness and transparency of the ***:This CPG contains 40 recommendations regarding the prevention,screening,diagnosis,treatment,and follow-up of early gastric cancer based on available clinical studies and *** provide recommendations for the timing of Helicobacter pylori eradication,screening populations for early gastric cancer,indications for endoscopic resection and surgical gastrectomy,follow-up interval after treatment,and other ***:This CPG can lead to optimum care for patients and populations by providing up-to-date medical *** intend this CPG for widespread adoption to increase the standard of prevention,screening,diagnosis,treatment,and follow-up of early gastric cancer;thereby,contributing to improving national health care and patient quality of life.

关键词： Early gastric cancer Prevention Screening Diagnosis Treatment Follow-up

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Synthesis, separation and identification of dinitropyrene isomers

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Journal of Environmental sciences 1993年第1期5卷 54-62页

作者： Wang Hai, li Baoqin, Xu Weibing, Jin Zuliang Xu XiaobaiResearch Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china

Dinitropyrenes (DNP) were prepared by nitration of pyrene, and the product was characterized by MS and elemental analysis. Three isomers of DNP were separated by HPLC and identified by 1H-NMR. The eating sequence on the normal phase column is 1, 3-DNP, 1, 6-DNP and 1, 8-DNP, whereas is 1, 6-DNP, 1. 8-DNP and 1. 3-DNP on the reversed phase column. The separation of three DNP isomers under different chromatographic conditions was also discussed.

关键词： dinitropyrenes environmental pollutant mutagen polycyclic aromatic hydrocarbon nitro-polycyclic aromatic hydrocarbon.

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Lunar ~3He estimations and related parameters analyses

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Science china Earth sciences 2010年第8期53卷 1103-1114页

作者： li DiHui, liU HeGuang, ZHANG WeiGuo, li Yun & XU ChuanDong Center for Space Science and Applied Research, chinese academy of sciences, beijing 100190, china Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China

As a potential nuclear fuel, 3He element is significant for both the solution of impending human energy crisis and the conservation of natural environment. Lunar regolith contains abundant and easily extracted 3He. Based on the analyses of the impact factors of 3He abundance, here we have compared a few key assessment parameters and approaches used in lunar regolith 3He reserve estimation and some representative estimation results, and discussed the issues concerned in 3He abundance variation and 3He reserve estimation. Our studies suggest that in a range of at least meters deep, 3He abundance in lunar regolith is homogeneously distributed and generally does not depend on the depth; lunar regolith has long been in a saturation state of 3He trapped by minerals through chemical bonds, and the temperature fluctuation on the lunar surface exerts little influence on the lattice 3He abundance. In terms of above conclusions and the newest lunar regolith depth data from the microwave brightness temperature retrieval of the "ChangE-1" Lunar Microwave Sounder, a new 3He reserve estimation has been presented.

关键词： lunar regolith 3He abundance reserve estimation maturity granularity composition solar wind flux CELMS

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^(40)Ar-^(39)Ar thermochronology of two ductile shear zones from Yiwulüshan,West liaoning Region: Age constraints on the Mesozoic tectonic events

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chinese Science Bulletin 2002年第13期47卷 1113-1118页

作者： ZHANG Xiaohui, li Tiesheng & PU ZhipingResearch Center of Mineral Resources Exploration, Institute of Geology and Geophysics, chinese academy of sciences, beijing 100101, china Guangzhou Institute of Geochemistry, chinese academy of sciences, Guangzhou 51 Research Center of Mineral Resources Exploration Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China

Two ductile shear zones trending EW and NNE respectively not only controlled the tectonic framework of the northern North china, but also constrained the geody-namic background for gold mineralization in this region. Field observations and microstructural analyses reveal that the EW trending ductile shear zones are mainly contributed to dextral compressional deformation resulting from top-to-the-southeast oblique thrust shearing, whereas the NNE trending ones are genetically related to sinistral strike-slip and extensional faulting. One sample from the former yielded an 40Ar-39Ar plateau age of (219±4) Ma (Bi) and two samples from the latter gave 40Ar-39Ar plateau ages of (116± 2) Ma (Bi) and (127±3) Ma (Bi). These ages provide constraints on the top-to-the-southeast oblique thrusting event occurring in Late Triassic and the sinistral extensional and strike-slip faulting event which occurred in Early Cretaceous.

关键词： 40Ar-39Ar age biotite ductile shear zone West liaoning Region.

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Exploiting pattern and sustainable development of marginal lands in the Three Gorge Reservoir Areas

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Journal of Environmental sciences 2001年第2期13卷 173-179页

作者： WU Gang, li Jing, KONG Hong mei, ZHAO Jing zhu, GAO lin (Department of Ecology System, Research Center for Eco Environmental sciences, chinese academy of sciences, beijing 100085, china) Department of Ecology System Research Center for Eco- Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

This paper studied the distribution and utilization status, reasonable exploitation patterns and potential productivity, and sustainable development of marginal lands in the Three Gorge Reservoir Areas. It has been pointed that problems of the soil fertility degradation, poor productivity in crop lands, natural disasters and environmental deterioration existed in all the exploited marginal lands. In order to maintain the sustainability of the marginal lands, following measure have been proposed: prohibiting cultivation in the crop lands with a slope more than 25°, restoring vegetation in the slope more than 25°, strengthening the basic agricultural construction, establishing the production base of woody feeds and oils, establishing a multi dimensional management model with reasonable structure and optimum function for forestry, agriculture and fishing.

关键词： marginal lands utilization pattern sustainable development Three Gorge Reservoir Are4

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Searching for Variable Stars in and around Open Clusters

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chinese Journal of Astronomy and Astrophysics 2002年第6期2卷 481-486页

作者： Yu Xin, Xiao-Bin Zhang and li-Cai DengNational Astronomical Observatories, chinese academy of sciences, beijing 100012 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present a snapshot-of our recent results of a variable star survey in 1 degree fields around three open clusters: NGC 188, NGC 7789 and M67. A total number of 39 variable stars are newly discovered, including 22 W ... 详细信息

关键词： open clusters : individual : NGC 188, NGC 7789 and M67 stars : variables

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