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   59篇
  完全免费   13篇
  2018年   9篇
  2017年   10篇
  2016年   9篇
  2015年   9篇
  2014年   9篇
  2013年   4篇
  2012年   3篇
  2011年   4篇
  2010年   3篇
  2009年   2篇
  2008年   2篇
  2007年   1篇
  2006年   1篇
  2004年   2篇
  2002年   1篇
  2001年   3篇
排序方式: 共有72条查询结果,搜索用时 109 毫秒
1.
Genetic similarity and diversity of cultured catfishSilurus asotus populations collected from two areas in western Korea were examined using randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Out of 20 random primers tested, 5 produced 1344 RAPD bands ranging from 8.2 to 13.6 polymorphic bands per primer. The polymorphic bands in these populations ranged from 56.4% to 59.6%. Polymorphic bands per lane within populations ranged from 4.9% to 5.3%. The similarity within the Kunsan population varied from 0.39 to 0.82 with a mean (± SD) of 0.56 ± 0.08. The level of bandsharing values was 0.59 ± 007 within the catfish population from Yesan. The genetic similarity in cultured catfish populations may have been caused because individuals from two populations were reared in the same environmental conditions or by inbreeding during several generations. However, in view of bandsharing values, polymorphic bands and also the specific major bands that were inter-population-specific, significant genetic differentiation between these populations were present even if bandsharing (BS) values were somewhat numerically different. Therefore, the number of RAPD polymorphisms identified in this study may be sufficient to permit estimating genetic similarity and diversity. However, in future, additional populations, sampling sites and individuals will be necessary to make up for these weak points.  相似文献
2.
All members of R. glutinosa show the unique characteristic of intrinsic tolerance to paraquat (PQ). Antioxidant enzymes have been proposed to be the primary mechanism of PQ resistance in several plant species. Therefore, the antioxidant enzyme systems of R. glutinosa were evaluated by comparatively analyzing cellular antioxidant enzyme levels, and their responses of oxidative stresses and hormones. The levels of ascorbate peroxidase (APX), glutathione reductase (GR), non-specific peroxidase (POX), and superoxide dismutase (SOD) were 7.3-, 4.9-, 2.7- and 1.6-fold higher in PQ-tolerant R. glutinosa than in PQ-susceptible soybeans. However, the activity of catalase (CAT) was about 12-fold higher in the soybeans. The activities of antioxidant enzymes reduced after PQ treatment in the two species, with the exception of POX and SOD in R. glutinosa, which increased by about 40 %. Interestingly, the activities of APX, SOD and POX in R. glutinosa, relative to those in soybeans, were further increased by 49, 67 and 93 % after PQ treatment. The considerably higher intrinsic levels, and increases in the relative activities of antioxidant enzymes in R. glutinosa under oxidative stress support the possible role of these enzymes in the PQ tolerance of R. glutinosa. However, the relatively lower levels of SOD versus PQ tolerance, and the mixed responses of antioxidant enzymes to stresses and hormones, suggest a possible alternative mechanism(s) for PQ tolerance in R. glutinosa.  相似文献
3.
4.
ABSTRACT This paper attempts to reveal the biogeographic characteristics of ant fauna of the islands among Korean South Sea, using quantitative analyses. The data treated in this paper are those from Cheongsando Is. and 10 other islands in South Sea which have been well investigated. The faunal similarity is examined using the Nomura-Simpson's Coefficient (NSC). Futhermore, the obtained NSC value matrix is examined by a cluster analysis using UPGMA method. The number of species which has been recorded in the 11 islands are 91 species belonging to 34 genera under 4 subfamilies. Among the above 11 islands, Jejudo Is., which is the largest, has the highest number of species, 67 spp., while Geogeumdo Is. has the lowest, 21 spp. Cheongsando Is. which has directly been investigated by authors has 30 species. The NSC- values between the 11 localities investigated range from 0.522 (Wando Is. to Saryangdo Is.) to 1.000 (Namhaedo Is. to Geojedo Is.). The comparative NSC value of Cheongsando Is. and 10 islands range from 0.522 (to Saryangdo Is.) to 0.833 (to Jejudo Is). The cluster analysis using a similarity index (NSC) showed that the islands of these areas could be grouped into 3, a level of 32%. The similarity of Soando Is. and Geomundo Is. were the closest, 63%, while Soando Is. and Namhaedo Is. were the remotest, 32%. The similarity of Jindo Is. and Cheongsando Is, was 63%, while that of Namhaedo Is. and Cheongsando Is. was 32%.  相似文献
5.
This study was carried out qualitatively and quantitatively to investigate the presence and the concentrations of anabolic steroids in urine collected from orally administered humans. Microanalysis of conjugated steroids by gas chromatography and mass spectrometry (GC/MS) has been carried out. Following oral administration three major metabolites of anabolic steroid drugs have been detected and partially characterized. The six steroids can be analysed at the same time in 17 min. The lower detection limit was 10 ng/ml in 5 ml of urine. The conjugated steroids from urine were centrifuged to 2,430g for 10 min, the supernatant solution passed through Amberlite XAD-2 column and the steroids eluted fraction esterified by using MSTFA and TMSI. The rate of metabolism and urinary excretion seem to be reasonably fast.  相似文献
6.
In South Korea, the north border area has been under vivax malaria epidemic since 1993. However, Jeollabuk-do, which is about 300 kms from the border, has not experienced the same epidemic. I investigated a total of 58 notified cases of malaria in Jeollabuk-do in the year 2000. All of the cases had an exposure history in the epidemic area. Among them were 49 ex-soldiers, 3 soldiers who served near the border area and 6 civilians who traveled there. The causal agent of all cases was Plasmodium vivax. Except the civilians, the soldiers and ex-soldiers were aged in their twenties. In the present study, the incubation period was from 6 to 520 days with a median of 157 days, and the latent onset type (92%) was more prevalent than the early onset type. Illness onset of most cases (86%) peaked during the summer season (June to September) despite of variable incubation periods. The time lag for diagnosis ranged from 2 to 42 days with a median of 11 days. Jeollabuk-do has not been an area of epidemic until now, but incidences have been increasing annually since 1996. In Jeollabuk-do, early diagnosis and treatment can be a feasible disease control measure to prevent spreading from the epidemic area.  相似文献
7.
Kim Y  Kim JS  Kim G  No YJ  Yoo HW 《Mutation research》2006,593(1-2):116-120
Mutations in the NOTCH3 gene (NOTCH3) are responsible for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), an adult-onset hereditary angiopathy leading to ischemic episodes, vascular dementia and other neurologic deficits. All mutations of NOTCH3 described so far are strictly stereotyped, leading to the gain or loss of a cysteine residue in a given epidermal growth factor (EGF)-like repeat of NOTCH3. We report two novel mutations of NOTCH3, R587C and C988Y, each resulting in an odd number of cysteine residues in an EGF-like repeat of NOTCH3. We identified these mutations in two unrelated Korean families with CADASIL, who presented with magnetic resonance imaging (MRI) abnormalities typical of CADASIL. These findings confirm that mutations in NOTCH3 are associated with the pathogenesis of CADASIL across different ethnic backgrounds.  相似文献
8.
Cercaria yamagutii Ito, 1957, was found in the marine mesogastropods Lunatia fortuni and Glossaulax didyma from the tidelands of Simpo located at the estuary of the Mankyoung River, which runs to the western coast of Korea. Metacercariae were found in a marine bivalve Mactra veneriformis after being infected with C. yamagutii experimentally. When a sea gull, Larus crassiostris, was fed with the metacercariae collected from the infected M. veneriformis, adult worms were recovered 10 days later. It was confirmed that the parasites collected from L. crassiostris were Acanthoparyphium tyosenense Yamaguti, 1939. From the results of this life cycle study, it was determined that the first intermediate hosts of A. tyosenense are L. fortuni and G. didyma. The second intermediate and final hosts are M. veneriformis and L. crassiostris, respectively. Mactra veneriformis was experimentally infected with C. yamagutii isolated from L. fortuni and G. didyma by maintaining them in a water tank for 30 min at about 20 C. The cercariae entered M. veneriformis through their incurrent siphons. Five hours after infection, the cercariae tails began to separate from the bodies, and the cercariae formed cysts. Mature cysts were formed 340 hr (14 days) after infection and identified as the metacercariae of A. tyosenense. The prevalence of A. tyosenense metacercariae was 99.5% in naturally infected M. veneriformis. This is the first report of C. yamagutii as the cercaria of A. tyosenense, and the complete life cycle of A. tyosenense was established in Korea.  相似文献
9.
Poly(acrylic acid) (PAA)-patterned polystyrene (PS) substrates were prepared by ion beam lithography to control cell behaviors of mouse fibroblasts and human embryonic kidney cells. Thin PAA films spin-coated on non-biological PS substrates were selectively irradiated with energetic proton ions through a pattern mask. The irradiated substrates were developed with deionized water to generate negative-type PAA patterns. The surface characteristics of the resulting PAA-patterned PS surface, such as surface morphology, chemical structure and composition and wettability, were investigated. Well-defined 100 μm PAA patterns were effectively formed on relatively hydrophobic PS substrates by ion beam lithography at higher fluences than 5 × 1014 ions/cm2. Moreover, based on the in vitro cell culture test, cells were adhered and proliferated favorably onto hydrophilic PAA regions separated by hydrophobic PS regions on the PAA-patterned PS substrates, and thereby leading to the formation of well-defined cell patterns.  相似文献
10.
A mini-microscope-based system for multisite detection of cardiovascular toxicity was developed. The mini-microscope consisted of an image sensor and lens module extracted from an inexpensive webcam. The flipped lens module enabled cells to be magnified and monitored during testing. The portability and compactness of this system enables short-term and potential long-term experimentation inside a conventional incubator. The toxicity test results demonstrated that the normalized beating rates of cardiac muscle cells selected from multiple regions increased over time when treated with 100 nM isoprenaline. The presented system could be a promising cost-effective cell-based testing tool for discovering and screening drugs.  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