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《BMJ (Clinical research ed.)》1971,3(5771):387-388
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沙棘灌丛林受害程度的预测模型   总被引:2,自引:0,他引:2  
我国沙棘灌丛林目前的灾害可分为生物灾害和非生物灾害。生物灾害以沙棘木蠹蛾危害为主,是近几年在内蒙古、辽宁、山西、宁夏和陕西等地大面积爆发的一种钻蛀性害虫;非生物灾害主要是立地和气候因素,总体表现为沙棘生长衰退,甚至出现大面积枯死。对辽宁省建平县和内蒙古敖汉旗不同受害程度沙棘灌丛林进行抽样调查,共设50块标准地,分别调查沙棘死亡株率、有叶树冠比例、沙棘木蠹蛾危害株率和20cm根干部沙棘木蠹蛾虫口数等沙棘受害指标,同时调查记录坡向、坡位、坡度、树高、地径和林分密度等多项生跃环境因子。通过模糊综合评判法,对4种受害特征指标进行权重分配,并根据综合评判值的大小,将沙棘灌丛林的受害程度分为健康、轻、中和重4个等级,以坡向、坡位、坡度、树高、地径和林分密度为预测因子,分别构建沙棘灌丛林受害程度BP神经网络模型和Logistic模型,BP神经网络的拟合率达88.1%,预留样本检验准确率为75%,Logistic模型的概率一致率为69.4%。在其它条件相同的情况下,坡位对受害程度的影响是其它因素的4.93倍。  相似文献   

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The ABO blood group system in humans has three different carbohydrate antigens named A, B, and O. The A antigen sequence is terminal trisaccharide N-acetylgalactosamine (GalNAc)α1-3[Fucα1-2]Galβ-, B is terminal trisaccharide Galα1-3[Fucα1-2]Galβ-, and O is terminal disaccharide Fucα1-2Galβ-. The single ABO gene locus has three alleles types A, B and O. The A and B genes code A and B glycosyltransferases respectively and O encodes an inactive enzyme. A large allelic diversity has been found for A and B transferases resulting in the genetic subgrouping of each ABO blood type. Genes for both transferases have been cloned and the 3D structure of enzymes with and without substrate has been revealed by NMR and X ray crystallography. The ABO blood group system plays a vital role in transfusion, organ and tissue transplantation, as well as in cellular or molecular therapies.  相似文献   

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The ABO blood group system in humans has three different carbohydrate antigens named A, B, and O. The A antigen sequence is terminal trisaccharide N-acetylgalactosamine (GalNAc)α1-3[Fucα1-2]Galβ-, B is terminal trisaccharide Galα1-3[Fucα1-2]Galβ-, and O is terminal disaccharide Fucα1-2Galβ-. The single ABO gene locus has three alleles types A, B and O. The A and B genes code A and B glycosyltransferases respectively and O encodes an inactive enzyme. A large allelic diversity has been found for A and B transferases resulting in the genetic subgrouping of each ABO blood type. Genes for both transferases have been cloned and the 3D structure of enzymes with and without substrate has been revealed by NMR and X ray crystallography. The ABO blood group system plays a vital role in transfusion, organ and tissue transplantation, as well as in cellular or molecular therapies.  相似文献   

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J. Bouw  G. E. Nasrat  C. Buys 《Genetica》1964,35(1):47-58
The mode of inheritance of blood groups in man and animals has been a matter of discussion as long as investigations in this field have been performed.A series of aberrations from the usual transmission of genes controlling the blood groups of the system B of cattle is presented. These data offer a contribution to the assumption that the blood groups are controlled by linked genes.On leave from the Faculty of Agriculture, University of Cairo, Egypt, U.A.R.  相似文献   

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The accuracy of regular serum methods to detect ABO blood groups can be negatively affected by some factors, such as irregular antibodies, autoantibodies or effects of diseases leading to false or weak agglutination. This study aimed to accurately identify ambiguous ABO blood groups by serological and gene detection methods. The samples were collected in the First Affiliated Hospital of Nanjing Medical University from December 2018 to December 2019. ABO genotyping was performed by polymerase chain reaction-sequence specific primer (PCR-SSP) method in 20 samples, and ABO exons 6 and 7 or FUT1 and FUT2 genes were sequenced in 5 samples. The genes detected in the 21 specimens included 4 cases of A/B, 2 cases of A205/O01, 3 cases of A/O01, 3 cases of A/O02, 1 case of O01/O01, 1 case of O01/O02, 1 case of B/O01, 1 case of B/O02, 1 case of Bel/O01, 1 case of Cisab01/O01, 1 case of rare B/O04, 1 case of Bombay-like Bmh, 1 case of new gene showing c.261del G of exon 6, c.579 T > C of exon 7 and B new/O01. This study suggests that ABO blood group genotyping technology combined with serological typing can be used for accurately typing ambiguous blood groups.  相似文献   

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红细胞的Na—K—Cl联合转运系统   总被引:1,自引:0,他引:1  
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Recent data available in literature and the author's data about the state of the antioxidant protection of the blood plasma have been generalized. The role of superoxide dismutase as the basic compound of the antioxidant system is discussed. The character of individual macromolecules (transferrin, ceruloplasmin, albumin) which have shown nonenzymatic specific antioxidant properties is presented. Possible mechanisms of biological activity of some antioxidants have been examined.  相似文献   

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