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891.
There are abundant insulin receptors on the membrane of myocytes, which renders cardiomyocytes typical target cells of insulin. Accumulating evidence has indicated that abnormal insulin level is an important predisposing factor in diabetes-related cardiovascular disorders and may contribute to the development of cardiovascular diseases, such as coronary heart diseaseand heart failure. It has been shown that insulin couldreduce infarct size in experimental animals subjected to myocardial ischem…  相似文献   
892.
In addition to the wide spread peraluminous granites, some alkaline or alkali-rich intrusive rocks were recently observed in the Wuyi Mountains. The Yangfang aegiriteaugite syenites in the Wuyi Mountains are strongly enriched in light rare earth elements (LREE), K, Ba, Ga, Zr and Y. What is more, differentiations of REE are obvious. In addition, the Yangfang aegiriteaugite syenites have also some characteristics similar to A-type granite. Zircons are selected from the Yangfang aegiriteaugite syenites for Sensitive High-Resolution Ion Microprobe (SHRIMP-Ⅱ) U-Pb geochronology study. 15 analyses give concordant 206Pb/238U ages in a narrow range of 233—249 Ma, which correspond to a single age population with a weighted mean 206Pb/238U age of 242 4 Ma, which records the crystallization time of the aegiriteaugite syenites. It is suggested that: (1) there were early Triassic peralkaline intrusive rocks in South China; (2) the early Indosinian extension event was probably active in local area, South China. This discovery provides a new insight for farther understanding of 揑ndosinian orogeny in South China.  相似文献   
893.
The recent discovery of superconductivity at 39 K in the superconductor MgB2[1] shows that intermetallic compounds with simple structure types are worth serious reconsideration as sources of new superconducting mate-rials. Subsequent to this discovery, He et al. observed a new intermetallic superconductor MgCNi3[2] at about 8 K. The perovskite crystal structure for MgCNi3 is shown in Fig. 1, with the atomic positions: Mg: 1a (0,0,0), C: 1b (0.5,0.5,0.5) and Ni: 3c (0,0.5,0.5). This mater…  相似文献   
894.
A novel permanent magnetic bearing has been developed, which consists of two magnetic rings with differenl dimensions in the same direction of axial magnetization, located concentrically. Because of the effect of magnetic field, the magnetic rings keep a distance axially from each other. If the distance between the two rings changes, a rehabilitalion force is produced to return to the original po-sition. When this distance decreases, a repeiling force will be generated; its component in axial direction can be used as a magnetic spring and its radial component can function as a bearing. With this novel permanent magnetic bearing, an impeller totai artificial beart (TAH) is designed, manufactured and tested. The rotation is driven radially. On the left and right sides of the rotor magnets, two small magnetic rings are fixed onto the rotor, coupling with two big magnetic rings on both sides of the motor coil, to form the magnetic bearings. Hereby the bearings are used for wear reduction rather than rotor l  相似文献   
895.
An important discovery in the Kaili Biota has been made recently, and many interesting components from ChengjiangBiota and Burgess Shale Biota have been discovered. Among them Marrella, only known from mid-Middle Cambrian Burgess Shale Biotaof British Columbia, Canada, is one of the most important arthropods fossils. Because the Kaili Biota is older than the Burgess Shale Biota,the strange head shield of Marrella occurring in the Kaili Biota outside Laurentia ranges from mid-Middle Cambrian to early Middle Cam-brian and is significant for the reconstruction of palaeogeography and evolutionary study of early metazoa. In the present paper Marrellasp. is reported for the first time in Asia.  相似文献   
896.
The paleo oceanenvironmentalchangeduringthePrecambrian Cambriantransitionisakeyissuere latedtothecausesforanexplosiveradiationofdiffer entmetazoanphyladuringtheEarlyCambrianera .Thechemicalandisotopiccompositionsofmarinesed iments (carbonates ,phosphorites ,siliceousrocks ,andblackshales)recordthechangingcompositionandphysicalconditionsoftheseawaterinwhichtheserocksaccumulated .Organiccarbon richblackshalesfrommarineenvironmentsarecommonlyenrichedinanumberoftraceelementssuchasNi,Mo ,V ,Co ,…  相似文献   
897.
Severalmonthsago ,anoutbreakofsevereacuterespiratorysyndrome (SARS )startedtospreadaroundtheworld .Asofthiswriting (May 14 ,2 0 0 3) ,morethan 75 0 0 personshavebeeninfectedinasmanyas 2 9countries[1] .The pathogencausingSARShasalreadybeenidentifiedtobeSARS Covbyanumberoflaboratoriesworldwide[2 ,3] .Severedis easesinanimals ,suchasthediseasescausedbyporcinetransmissiblegastroenteritisvirus (TGEV ) ,murinehepatitisvirus (MHV)andporcinehemagglu tinatingencephalomyelitisvirus (PHEV ) ,ha…  相似文献   
898.
The evolution of immunology as a scientific discipline, and the current status of immunology research in China and some other countries in the world, is surveyed. Some of the directions in which the field should be highlighted in the future are speculated on.  相似文献   
899.
大桩距水泥搅拌桩复合地基桩土应力试验   总被引:3,自引:1,他引:3  
通过对复合地基静载荷试验和桩土应力比测试,对软土地基上某住宅小区设计的大桩距水泥搅拌桩复合地基的承载性状和桩土应力比进行全面探讨,为大桩距水泥搅拌桩在软基上的设计应用提供了可靠的资料和经验。  相似文献   
900.
利用Wigner函数的基本性质和空间变量的对易关系中包含的坐标-坐标的非对易性,用量子力学来处理阻尼系统,得到的阻尼谐振子在非对易空间中的Wigner函数与对易空间形式一致.  相似文献   
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