首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   34篇
  免费   1篇
  2022年   1篇
  2020年   1篇
  2019年   3篇
  2018年   1篇
  2017年   2篇
  2016年   3篇
  2015年   4篇
  2013年   3篇
  2012年   1篇
  2011年   1篇
  2009年   1篇
  2008年   3篇
  2007年   3篇
  2006年   5篇
  2004年   1篇
  2003年   1篇
  2000年   1篇
排序方式: 共有35条查询结果,搜索用时 15 毫秒
21.
The objective was to determine the effects of supplementing hexoses in oocyte maturation and embryo culture medium on in vitro maturation (IVM) and in vitro fertilization (IVF) of porcine oocytes and in vitro development of in vitro produced (IVP) porcine embryos. In the first experiment, oocytes were matured in vitro in modified North Carolina State University (NCSU)-37 medium, supplemented with hexoses (glucose, fructose or galactose) at various concentrations: 0 (control), 2.5, 5.5 and 10 mM. Supplementing the maturation medium with either glucose or fructose (5.5 mM) increased the percentages of oocytes that matured to metaphase II (79.4 and 70.2%, respectively), as compared with the control group (P < 0.05). However, supplementing galactose had no effects on meiotic maturation and fertilization. In the second experiment, cleaved embryos were collected 3 days after IVF of oocytes matured in the maturation medium supplemented with 5.5 mM of glucose; they were cultured for an additional 4 days in modified NCSU-37 medium, supplemented with 5.5mM of glucose, fructose or galactose. The incidence of blastocyst formation was higher (P < 0.05) in the glucose and fructose groups (18.6 and 18.2%, respectively) than in the galactose group and non-supplemented control group (12.9 and 9.2%). Moreover, fructose supplementation increased the total cell number/blastocyst (48.0 versus 37.6) and reduced the index of DNA-fragmented nucleus in the blastocysts (7.6% versus 11.8%), as compared with glucose supplementation (P < 0.05). In conclusion, fructose was a practical alternative to glucose for supporting IVM of porcine oocytes and fructose was superior to glucose for producing high-quality porcine embryos in vitro.  相似文献   
22.
23.
Field tests of three synthetic sex pheromone blends (Japanese blend: Z11–18:Ald (55 μg), Z13–18:Ald (500 μg), Z11–18:OH (120 μg) and Z13–18:OH (180 μg), Indian blend: Z11–16:Ac (50 μg) and Z13–18:Ac (500 μg) and Philippine blend: Z11–16:Ac (500 μg) and Z13–18:Ac (10 μg) based on geographic variations in sex pheromones) of the rice leaffolder moth, Cnaphalocrocis medinalis Guenée (Lepidoptera: Crambidae), were conducted at Yogyakarta (Java), and at Sempidi and Penatih (Bali), Indonesia. Only the Japanese blend attracted significant numbers of male C. medinalis, while neither the Indian nor the Philippine blend showed any attractiveness to the males. In the GC–MS analysis of a crude extract from pheromone glands of female C. medinalis collected at Sanur, Bali. Indonesia, Z11–18:Ald, Z13–18:Ald, Z11–18:OH and Z13–18:OH were detected at a ratio of 10:100:26:37, and the total amount was approximately 0.8 ng/female. Neither Z11–16:Ac nor Z13–18:Ac were detected. These results suggest that C. medinalis that respond to the Japanese blend are widely distributed from Eastern Asia through Southeast Asia.  相似文献   
24.
25.
To enable both the multiplication of elite livestock and the engineering of transgenic animals for various agricultural and biochemical purposes, scientists around the world are intensively studying efficient ways of improving developmental competency of bovine embryos reconstructed by somatic cell nuclear transfer. Because it is widely accepted that culture conditions along with many other factors contribute to the developmental competency of reconstructed embryos, this preliminary study was designed to test whether or not bovine reconstructed embryos could develop in vitro using a simple portable CO(2) incubator. CO(2) and O(2) gas tensions and air pressure can be varied using this system. The parameters used in the five conducted trials were low CO(2) (2-5%) and O(2) (8-10%) gas tensions, and negative air pressure (of 300 mm Hg). Chamber temperature was maintained at 38.5 degrees C. Bovine fetal fibroblasts were used as donor karyoplasts and were fused into microsurgically enucleated M II oocytes followed by activation and culture. From the 250 enucleated oocytes, 217 (86.8%) fused, 183 (73.2%) cleaved, and 43 (17.2%) developed to the blastocyst stage. While relatively low developmental rates were achieved, technical proficiency may have been a contributing factor. Further studies using this system are needed to determine optimal levels of O(2), CO(2), and air pressure.  相似文献   
26.
As a global network, countries are being asked to meet goals set forth in the Global Health Security Agenda (GHSA) for a workforce capable of effective and efficient prevention, detection and response to infectious disease threats. There is great need for a cross-sectoral workforce that can innovate and problem-solve. To achieve GHSA goals, countries need a way to visualize their existing system, identify opportunities for improvement, and achieve improved cross-sectoral interactions. The One Health Systems Mapping and Analysis Resource Toolkit (OH-SMART) was successfully piloted in West Sumatra, Indonesia, and was used to enhance multi-agency collaboration around infectious disease outbreaks and proved to be an adaptable, scalable process requiring minimal resources. The authors present OH-SMART as a potential tool to help countries analyze their existing health system and create relevant action steps to improve cross-sectoral collaborations.  相似文献   
27.
The ability to cryopreserve in vitro-produced feline embryos was investigated. To improve the survival rate of cryopreserved embryos, first the developmental ability of in vitro fertilized feline zygotes (after removal of intracellular lipids) was determined, followed by the post-thaw survival of cryopreserved blastocysts derived from delipidated zygotes. More than 67% of the delipidated zygotes cleaved and 36% of them developed to the morula stage. The developmental ability of delipidated zygotes to the blastocyst stage (26%) was similar to that of sham-operated (30.5%) or control embryos (31.3%). Although the survival rate of delipidated blastocysts (81.8%) after freezing and thawing tended to be higher than that of control embryos without delipidation (60.6%), rates were not significantly different between the both groups. In conclusion, in vitro-produced feline blastocysts were successfully frozen, removal of the cytoplasmic lipid content in feline zygotes did not impair their in vitro developmental competence (up to the blastocyst stage), and reduction of cytoplasmic lipids by aspiration had no apparent effects on the survival of in vitro-derived blastocysts after cryopreservation.  相似文献   
28.
29.
The present study was designated to examine the possibility of producing somatic cell nuclear transfer (SCNT) embryos in pigs using oocyte cytoplasm fragments (OCFs), prepared by centrifugations, as recipient cytoplasts. In Experiment 1, in vitro matured oocytes were centrifuged at 13,000 x g for 3, 6, and 9 min to stratify the cytoplasm, and then the oocytes were freed from zona pellucida and recentrifuged at 5,000 x g for 4 sec in Percoll gradient solution to produce OCFs as the source of recipient cytoplasts. It was found that a long duration of the first centrifugation tends to produce large-sized OCFs after the second centrifugation. In Experiment 2, two or three cytoplasts without chromosomes were aggregated, and then they were fused with a cumulus cell to produce SCNT embryos. The results showed that 66.4 +/- 9.4% of the reconstructed embryos underwent premature chromosome condensation at 1 h after activation, and 85.2 +/- 7.1% and 61.6 +/- 7.0% of them had pseudopronuclei at 10 and 24 h after activation, respectively. In Experiment 3, when SCNT embryos reconstructed by the fusion of three cytoplasts and one cumulus cell, a significantly higher (p < 0.05) rate of reconstructed embryos developed to the blastocyst stage (10.6 +/- 1.8%) than that of reconstructed with two cytoplasts and one cumulus cell (5.2 +/- 1.5%). These results indicate that cytoplasts obtained by two centrifugations can support the remodeling of a transferred somatic nucleus, resulting in the development of the reconstructed porcine embryos to the blastocyst stage.  相似文献   
30.
Although Indonesia has been rabies-infected since at least the 1880s, some islands remain rabies-free, such as Lombok. However, due to its adjacency to rabies-infected islands such as Bali and Flores, there is considerable risk of a rabies incursion. As part of a rabies risk assessment project, surveys were conducted to estimate the size of the dog population and to describe dog management practices of households belonging to different ethnic groups. A photographic-recapture method was employed and the number of unowned dogs was estimated. A total of 400 dog owning households were interviewed, 300 at an urban site and 100 at a rural site. The majority of the interviewed households belonged to the Balinese ethnic group. Owned dogs were more likely male, and non-pedigree or local breed. These households kept their dogs either fully restricted, semi-free roaming or free-roaming but full restriction was reported only at the urban site. Dog bite cases were reported to be higher at the urban site, and commonly affected children/young adults to 20 years old and males. A higher number of unowned dogs was observed at the urban site than at the rural site. Data generated within these surveys can inform rabies risk assessment models to quantify the probability of rabies being released into Lombok and resulting in the infection of the local dog population. The information gained is critical for efforts to educate dog owners about rabies, as a component of preparedness to prevent the establishment of rabies should an incursion occur.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号