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51.
研究了p-赋范空间中保距离1的映射以及非扩张映射.证明了:若p-赋范空间中的映射保2个或者3个距离,则为等距映射. 相似文献
52.
53.
提出了SIQS模型,研究了路途感染和出境健康检查对疾病传播的影响,获得了如下结果:如果基本再生数R0γθ≤1,无病平衡点全局渐近稳定;如果基本再生数R0γθ>1,综合利用Routh-Hurwitz准则和Gersgorin圆盘定理,得到了地方性平衡点局部渐近稳定性;此外,还证明了如果地方性平衡点存在,疾病是持久的.数学结论表明,出境健康检查能减少感染者出境数量和路途感染的发生率,有利于疾病的消失. 相似文献
54.
根据1997～2000年东海23°30′～33°N、118°30′～128°E海域4个季节海洋调查资料,对东海毛颚类种类组成、多样性分布特征及与环境关系进行分析。结果表明:春、夏季毛颚类种类最丰富(25种),冬季次之(23种),秋季种数最低(21种);冬、春季毛颚类种数仅与表层温度相关,夏季与表层温度、表层盐度二元线性相关,秋季与表层盐度相关;冬、春季毛颚类多样性和丰富度指数值由北向南,由近海向外海逐渐增高,夏季近海和外海差异缩小,秋季多样性指数值为4季最低。 相似文献
55.
Large-scale deployment of a rice 6 K SNP array for genetics and breeding applications 总被引：1，自引：0，他引：1
Michael J. Thomson Namrata Singh Maria S. Dwiyanti Diane R. Wang Mark H. Wright Francisco Agosto Perez Genevieve DeClerck Joong Hyoun Chin Geraldine A. Malitic-Layaoen Venice Margarette Juanillas Christine J. Dilla-Ermita Ramil Mauleon Tobias Kretzschmar Susan R. McCouch 《Rice》2017,10(1):40
Background
Fixed arrays of single nucleotide polymorphism (SNP) markers have advantages over reduced representation sequencing in their ease of data analysis, consistently higher call rates, and rapid turnaround times. A 6 K SNP array represents a cost-benefit “sweet spot” for routine genetics and breeding applications in rice. Selection of informative SNPs across species and subpopulations during chip design is essential to obtain useful polymorphism rates for target germplasm groups. This paper summarizes results from large-scale deployment of an Illumina 6 K SNP array for rice.Results
Design of the Illumina Infinium 6 K SNP chip for rice, referred to as the Cornell_6K_Array_Infinium_Rice (C6AIR), includes 4429 SNPs from re-sequencing data and 1571 SNP markers from previous BeadXpress 384-SNP sets, selected based on polymorphism rate and allele frequency within and between target germplasm groups. Of the 6000 attempted bead types, 5274 passed Illumina’s production quality control. The C6AIR was widely deployed at the International Rice Research Institute (IRRI) for genetic diversity analysis, QTL mapping, and tracking introgressions and was intensively used at Cornell University for QTL analysis and developing libraries of interspecific chromosome segment substitution lines (CSSLs) between O. sativa and diverse accessions of O. rufipogon or O. meridionalis. Collectively, the array was used to genotype over 40,000 rice samples. A set of 4606 SNP markers was used to provide high quality data for O. sativa germplasm, while a slightly expanded set of 4940 SNPs was used for O. sativa X O. rufipogon populations. Biparental polymorphism rates were generally between 1900 and 2500 well-distributed SNP markers for indica x japonica or interspecific populations and between 1300 and 1500 markers for crosses within indica, while polymorphism rates were lower for pairwise crosses within U.S. tropical japonica germplasm. Recently, a second-generation array containing ~7000 SNP markers, referred to as the C7AIR, was designed by removing poor-performing SNPs from the C6AIR and adding markers selected to increase the utility of the array for elite tropical japonica material.Conclusions
The C6AIR has been successfully used to generate rapid and high-quality genotype data for diverse genetics and breeding applications in rice, and provides the basis for an optimized design in the C7AIR.56.
Ovine secretory IgA (sIgA) has been purified to relative homogeneity by ammonium sulphate precipitation (to 40 per cent w/v) of lung lavage fluid from 3- or 12-month-old lambs, followed by molecular sieve chromatography on a Sephacryl S300 matrix. Three peaks A, B and C with molecular sizes corresponding to 550,000, 400,000 and 165,000 respectively were eluted from the column. Immunoelectrophoresis, radial immunodiffusion and enzyme-linked immunosorbent assays (ELISAs) with class specific antiserum confirmed that peak B contained only IgA. Polyacrylamide gel electrophoresis of peak B under reducing conditions resolved three subunits corresponding to secretory component, heavy and light chains. Hybridomas generated by fusing spleen cells from IgA-primed Balb/C mice with murine myeloma (Sp2/0) were screened for IgA-specific monoclonal antibodies against a panel of ovine IgG2, IgG1, IgA and IgM. One particular clone, F3-4B4, identified as murine IgG1, was monospecific against ovine IgA with no cross reactivity against bovine immunoglobulins. This hybridoma was successfully tested as a serological probe by ELISA profiling to locate IgA containing fractions in the course of immunoglobulin purification from biological fluids. 相似文献
57.
58.
L F Lozano A A Bickford A E Castro J Swartzman-Andert R Chin C Meteyer G Cooper B Reynolds R L Manalac 《Journal of veterinary diagnostic investigation》1989,1(3):254-259
An enteric syndrome of turkey poults, characterized by enteritis, crop mycosis, intestinal changes (pale, thin-walled ballooning with watery contents), and rickets, occurred during 1988 in 74 turkey flocks from different farms belonging to 9 California turkey growers. The flocks ranged in size from 9,000 to 120,000 birds. Pools of intestine sections from 618 birds, representing 78 field cases, were examined. Histopathological examination of the intestines showed a mild to severe atrophy with a reduced depth of crypts, which was more prominent in the distal part of the small intestine. Viral isolation attempts with primary cell cultures of chicken embryo kidney cells were negative. Examination by electron microscopy of negatively stained intestinal specimens revealed the presence of Reoviridae particles of 58.8 to 80 nm in diameter. Enzyme-linked immunosorbent assay results on the intestinal pools for mammalian and group A avian rotaviruses were negative. A statistically significant relationship was found for the presence of Reoviridae particles in the intestines of 10-21-day-old birds. Of the 7 most common pathological conditions analyzed, 2, rickets and intestinal changes (thin-walled ballooning intestine with watery contents), showed a statistically significant association with the presence of Reoviridae particles. 相似文献
59.
Yi‐Chen Chen Shih‐Chieh Chang Yu‐Han Huang Ya‐Jane Lee Chao‐Chin Chang Jiunn‐Wang Liao Wei‐Li Hsu 《Veterinary and comparative oncology》2019,17(3):427-438
Neutrophil gelatinase‐associated lipocalin (NGAL) is a new biomarker for renal injury. It is also involved in tumorigenesis of different human cancer types. The oncogenic role of NGAL is related to its molecular forms, and heterodimer formation with matrix metalloproteinase 9 (MMP9) promotes human breast cancer (HBC) invasion and metastasis. To date, the levels of NGAL and NGAL/MMP9 complex have not yet been explored in canine mammary tumours (CMTs). Hence, this study aimed to investigate whether NGAL and its molecular forms could be the biomarker for CMT diagnosis. To this end, expression profile of NGAL and MMP9 in mammary epithelial cells as well as in urine samples were detected. By immunohistochemistry staining, NGAL was expressed at variable levels. Unlike HBC, a significant reduction in NGAL expression was demonstrated in benign and malignant CMTs as compared with normal controls. Additionally, NGAL expression was significantly reduced in dogs with metastatic CMTs. By contrast, the mean score of MMP9 expression in ascending order was normal groups, benign, and malignant CMTs. Interestingly, analysis of the molecular form revealed the NGAL/MMP9 complex presents in most mammary tissues and urine of dogs with benign or malignant CMTs, whereas the complex was absent in samples from dogs without CMTs. In conclusion, NGAL and MMP9 are ubiquitously expressed in canine mammary epithelial cells in normal and cancerous status. However, the NGAL/MMP9 complex exclusively presents in mammary tissues and urine of dogs with tumours. 相似文献
60.
Chin GY 《Science (New York, N.Y.)》1980,208(4446):888-894
Three notable new developments in magnetic alloys are highlighted. These include rare earth-cobalt permanent magnets with maximum energy products up to 240 kilojoules per cubic meter; chromium-cobalt-iron permanent magnets that have magnetic properties similar to those of the Alnicos, but contain only about half as much cobalt and are sufficiently ductile to be cold-formable; and high-induction grain-oriented silicon steels that exhibit 20 percent less core loss as transformer core materials than conventional oriented grades. 相似文献