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11.
Analysis of a large sample of well-dated fossil mammals from localities in the Turkana Basin of Kenya and Ethiopia revealed sampling biases that affect patterns of faunal turnover during the late Pliocene. When these biases were accounted for, results indicated that 58 to 77 percent of the mammal species were replaced between 3.0 and 1.8 million years ago (Ma). Overall diversity increased from 3.0 to 2.0 Ma but then declined. No distinct turnover pulse is seen between 2.8 and 2.5 Ma; instead, the most significant period of faunal change began after 2.5 Ma and continued through 1.8 Ma.  相似文献   
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An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.  相似文献   
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通过嫁接对木麻黄的亲本进行矮化是开展木麻黄杂交育种的重要技术基础。为了研究木麻黄 不同亲缘间嫁接对嫁接亲和力和花诱导的影响,以木麻黄属的短枝木麻黄(Casuarina equisetifolia)为砧 木,分别以同种的短枝木麻黄,同属不同种的细枝木麻黄(C. cunninghamiana)、粗枝木麻黄(C. glauca) 和不同属的滨海木麻黄(Allocasuarina littoralis)为接穗,开展木麻黄不同亲缘关系间的嫁接研究,研究 种内、种间和属间嫁接对木麻黄嫁接亲和力和花诱导的影响。研究结果表明,木麻黄种内嫁接的亲和力 最高,无性系接穗嫁接成活率高达91.4%,实生苗接穗为87.0%;而种间嫁接的亲和力显著低于种内嫁 接,细枝木麻黄接穗和粗枝木麻黄接穗嫁接成活率分别为36.0% 和45.0%;属间的嫁接未发现有成活的 例子,其嫁接亲和力为0。在嫁接对接穗的花诱导方面,种内嫁接的无性系接穗次年开花率为74.2%,显 著高于种内嫁接的实生苗接穗(42.3%)和种间嫁接的细枝木麻黄(39.8%)和粗枝木麻黄(35.6%)。  相似文献   
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Immune privileged mesenchymal stem cells (MSCs) can differentiate into multiple cell types and possess great potential for human and veterinary regenerative therapies. This study was designed with an objective to isolate, expand and characterize buffalo bone marrow‐derived MSCs (BM‐MSCs) at molecular and cellular level. Buffalo BM‐MSCs were isolated by Ficoll density gradient method and cultured in Dulbecco’s modified Eagle’s medium supplemented with fetal bovine serum (FBS). These cells were characterized through alkaline phosphatase (AP) staining, colony‐forming unit (CFU) assay, mRNA expression analysis (CD 73, CD 90, CD 105, Oct4 and Nanog), immunolocalization along with flow cytometry (Stro 1, CD 73, CD 105, Oct4, Sox2 and Nanog) and in situ hybridization (Oct4 and Sox2). Multilineage differentiation (osteogenic, adipogenic and chondrogenic) was induced in vitro, which was further assessed by specific staining. Buffalo BM‐MSCs have the capacity to form plastic adherent clusters of fibroblast‐like cells and were successfully maintained up to 16th passage. These cells were AP positive, and further CFU assay confirmed their clonogenic property. RT‐PCR analysis and protein localization study showed that buffalo BM‐MSCs are positive for various cell surface markers and pluripotency markers. Cytoplasmic distribution of mRNA for pluripotency markers in buffalo BM‐MSCs and multilineage differentiation were induced in vitro, which was further assessed by specific staining. To the best of our knowledge, this is the first report of buffalo BM‐MSCs, which suggests that MSCs can be derived and expanded from buffalo bone marrow and can be used after characterization as a novel agent for regenerative therapy.  相似文献   
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Cells are blessed with a group of stress protector molecules known as heat shock proteins (HSPs), amongst them HSP70, encoded by HSPA‐1A gene, is most abundant and highly conserved protein. Variety of stresses hampers the developmental competence of embryos under in vivo and in vitro conditions. Present work was designed to study the quantitative expression of HSPA‐1A mRNA in immature oocytes (IMO), matured oocytes (MO), in vitro produced (IVP) and in vivo‐derived (IVD) buffalo embryos to assess the level of stress to which embryos are exposed under in vivo and in vitro culture conditions. Further, HSPA‐1A gene sequence was analysed to determine its homology with other mammalian sequences. The mRNA expression analysis was carried out on 72 oocytes (40 IMO; 32 MO), 76 IVP and 55 IVD buffalo embryos. Expression of HSPA‐1A was found in oocytes and throughout the developmental stages of embryos examined irrespective of the embryo source; however, higher (p < 0.05) expression was observed in 8–16 cell, morula and blastocyst stages of IVP embryos as compared to IVD embryos. Phylogenetic analysis of bubaline HSPA‐1A revealed that it shares 91–98% identity with other mammalian sequences. It can be concluded that higher level of HSPA‐1A mRNA in IVP embryos in comparison with in vivo‐derived embryos is an indicator of cellular stress in IVP system. This study suggests need for further optimization of in vitro culture system in which HSPA‐1A gene could be used as a stress biomarker during pre‐implantation development.  相似文献   
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Background

Few previous studies have investigated the association between biomarkers and cardiac disease findings in dogs with naturally occurring myxomatous mitral valve disease (MMVD).

Aim

To investigate if histopathological changes at necropsy could be reflected by in vivo circulating concentrations of cTnI and aldosterone, and renin activity, in dogs with naturally occurring congestive heart failure because of MMVD.

Animals

Fifty privately owned dogs with MMVD and heart failure.

Methods

Longitudinal Study. Dogs were prospectively recruited and examined by clinical and echocardiographical examination twice yearly until time of death. Blood was stored for batched analysis of concentrations of cTnI and aldosterone, and renin activity. All dogs underwent a standardized necropsy protocol.

Results

cTnI were associated with echocardiographic left ventricular end‐diastolic dimension (P < .0001) and proximal isovolumetric surface area radius (< .004). Furthermore, in vivo cTnI concentrations reflected postmortem findings of global myocardial fibrosis (P < .001), fibrosis in the papillary muscles (P < .001), and degree of arterial luminal narrowing (< .001) Aldosterone or renin activity did not reflect any of the cardiac disease variables investigated.

Conclusion and clinical importance

Cardiac fibrosis and arteriosclerosis in dogs with MMVD are reflected by circulating cTnI concentration, but not by aldosterone concentration or renin activity. Cardiac troponin I could be a valuable biomarker for myocardial fibrosis in dogs with chronic cardiac diseases.  相似文献   
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