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   52篇
  免费   6篇
  58篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   2篇
  2018年   1篇
  2016年   5篇
  2013年   2篇
  2012年   3篇
  2011年   8篇
  2010年   2篇
  2009年   2篇
  2008年   5篇
  2007年   2篇
  2004年   6篇
  2003年   1篇
  2002年   2篇
  2001年   3篇
  2000年   4篇
  1994年   2篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1986年   1篇
  1974年   1篇
排序方式: 共有58条查询结果,搜索用时 0 毫秒
11.
A 9-year-old female child of healthy parents (mother: 43 years, father: 44 years) was referred to our center because of severe mental retardation. While pedigree analysis was not contributory, two older sibs were normal and healthy. Physical examination revealed facial dysmorphism, microcephaly and hyperflexibility of all joints. Her chromosome constitution showed a mosaic pattern; mos 46,XX[98]/47,XX,+22[2]. So skin biopsy was performed and mosaic trisomy 22 was confirmed with FISH analysis (46,XX[73]/47,XX,+22[27]). Physical features of this case seemed consistent with her mosaic constitution. This report would be a demonstrative example to show the significant contribution of FISH in states of mosaicism.  相似文献   
12.
We described trisomy 8 mosaicism in a 6-month-old boy with left corneal leukoma, strabismus, posterior urethral valve, tibial bowing and congenital pseudarthrosis of the tibia (CPT) on graphic of left tibia. The patient also had some minor anomalies such as short philtrum, full everted lower lip, microretrognathia, flexion contracture on his left thumb, deep palmar and plantar creases and three cafe-au-lait macules (CALM) larger than 1 cm on the abdomen. Peripheral blood karyotype analysis of the patient showed 46,XY(10%)/47,XY,+8 (90%)). Mosaic trisomy 8 is a rare syndrome characterized by renal, cardiac, ophthalmologic anomalies, dysmorphic facial features and some skeletal manifestations. When re-evaluated at 2 years of age, his gross motor development was delayed and he also had 12 CALM larger than 1 cm, hence the patient fulfilled NIH diagnostic criteria for Neurofibromatosis type 1 (NF 1) based on the CALM and CPT. A truncating mutation was found through comprehensive NF1 mutation analysis, i.e., c.1019_1020delCT (p.Ser340CysfsX12). Here we report a patient with both mosaic trisomy 8 and NF1, which was not described previously.  相似文献   
13.
14.
The effects of 50 microM lanthanum (La3+) on the contractile force, rate and coronary flow of rat hearts perfused with solutions containing 2.5, 5, 7.5 mM calcium (Ca2+) have been investigated. La3+ produced a rapid and marked decrease in contractile force within 1-3 min ("early La(3+)-effect"). The inhibition of contractility by La3+ was reduced progressively when the Ca2+ ion concentration in the perfusion fluid was raised from 2.5 to 7.5 mM. However, after 10-80 min of La3+ perfusion the contractile force was increased significantly ("late La(3+)-effect"). Elevation of Ca2+ during exposure to La3+ increased its effect. During the late La(3+)-effect, a marked decrease in heart rate and a significant increase in time to reach peak tension, time for half relaxation and twitch duration was observed. High concentrations of perfusate Ca2+ decreased the chronotropic response to La3+, in contrast, elevated Ca2+ potentiated La(3+)-induced increase in time to reach peak tension, time for half relaxation and twitch duration. La3+ produced a significant decrease in coronary flow. High Ca2+ augmented the decrease coronary flow. The findings indicate that La3+ may produce marked effects on myocardial function. High extracellular Ca2+ reduces the La(3+)-induced initial decrease in force of contraction, but potentiates the late increase in contractile force by La3+. Elevated external Ca2+ also increases the effects of La3+ on twitch parameters, heart rate and coronary flow.  相似文献   
15.
In this study, total phenolic and flavonoid analyses of flower, leaf, and stem aqueous extracts of C. orientalis were performed. Total phenolic contents of C. orientalis extracts ranged from 12.2±0.06 to 19.0±0.07 mg GAE/g extract. Total flavonoid values range between 2.0±0.11 and 6.6±0.19 mg CE/g extract. Urease, collagenase, tyrosinase, and α-glucosidase inhibition activities were determined in vitro and the relationship between them was examined. IC50 results for all enzymes were obtained between 0.18 and 3.53 μg/mL. The aqueous extract of the plant C. orientalis showed potent cytotoxic effects against the human colon cancer cell lines DLD-1. As the extract concentration increases, cell death increases. The main fatty acid composition by GC/MS analysis is erucic acid (36.5 %). The potential binding modes of the fatty acids in the plant extract to the enzymes and possible inhibition mechanisms were determined by molecular docking calculation.  相似文献   
16.
This study examined the effect of different apple cultivars upon the UV inactivation of Escherichia coli O157:H7 strains within unfiltered apple cider. Apple cider was prepared from eight different apple cultivars, inoculated with approximately 106 to 107 CFU of three strains of E. coli O157:H7 per ml (933, ATCC 43889, and ATCC 43895), and exposed to 14 mJ of UV irradiation per cm2. Bacterial populations for treated and untreated samples were then enumerated by using nonselective media. E. coli O157:H7 ATCC 43889 showed the most sensitivity to this disinfection process with an average 6.63-log reduction compared to an average log reduction of 5.93 for both strains 933 and ATCC 43895. The highest log reduction seen, 7.19, occurred for strain ATCC 43889 in Rome cider. The same cider produced the lowest log reductions: 5.33 and 5.25 for strains 933 and ATCC 43895, respectively. Among the apple cultivars, an average log reduction range of 5.78 (Red Delicious) to 6.74 (Empire) was observed, with two statistically significant (α ≤ 0.05) log reduction groups represented. Within the paired cultivar-strain analysis, five of eight ciders showed statistically significant (α ≤ 0.05) differences in at least two of the E. coli strains used. Comparison of log reductions among the E. coli strains to the cider parameters of °Brix, pH, and malic acid content failed to show any statistically significant relationship (R2 ≥ 0.95). However, the results of this study indicate that regardless of the apple cultivar used, a minimum 5-log reduction is achieved for all of the strains of E. coli O157:H7 tested.  相似文献   
17.
Ventilatory acclimatization to hypoxia is a time-dependent increase in ventilation and the hypoxic ventilatory response (HVR) that involves neural plasticity in both carotid body chemoreceptors and brainstem respiratory centers. The mechanisms of such plasticity are not completely understood but recent animal studies show it can be blocked by administering ibuprofen, a nonsteroidal anti-inflammatory drug, during chronic hypoxia. We tested the hypothesis that ibuprofen would also block the increase in HVR with chronic hypoxia in humans in 15 healthy men and women using a double-blind, placebo controlled, cross-over trial. The isocapnic HVR was measured with standard methods in subjects treated with ibuprofen (400mg every 8 hrs) or placebo for 48 hours at sea level and 48 hours at high altitude (3,800 m). Subjects returned to sea level for at least 30 days prior to repeating the protocol with the opposite treatment. Ibuprofen significantly decreased the HVR after acclimatization to high altitude compared to placebo but it did not affect ventilation or arterial O2 saturation breathing ambient air at high altitude. Hence, compensatory responses prevent hypoventilation with decreased isocapnic ventilatory O2-sensitivity from ibuprofen at this altitude. The effect of ibuprofen to decrease the HVR in humans provides the first experimental evidence that a signaling mechanism described for ventilatory acclimatization to hypoxia in animal models also occurs in people. This establishes a foundation for the future experiments to test the potential role of different mechanisms for neural plasticity and ventilatory acclimatization in humans with chronic hypoxemia from lung disease.  相似文献   
18.
Summary Using restriction endonuclease analysis, oligonucleotide hybridization, and direct sequencing of amplified genomic DNA, we characterized 11 different mutations in the DNA of 26 patients from Turkey homozygous for -thalassemia. We found that mutations IVS-1 nt110, IVS-1 nt6, and the frameshift at codon 8 were the most frequent. By direct sequencing we characterized two very rare mutations not previously reported in the Turkish population: a frameshift +1 at codons 9/10 and a nonsense mutation at codon 15.  相似文献   
19.
Summary An ultraviolet spectrophotometric method was used to monitor the formation of soluble ferric iron in acid culture solutions of Thiobacillus ferrooxidans. This methodology was demonstrated to be applicable for determining both pyrite and ferrous ion oxidation. Kinetic parameters of Fe2+ oxidation determined with the use of this method were in close agreement with those previously obtained by measurement of oxygen uptake rates.  相似文献   
20.
(S)‐(?)‐1‐(1′‐napthyl)‐ethanol (S‐NE) is an important intermediate for the preparation of mevinic acid analogs, which is used for the treatment of hyperlipidemia. The objectives of the study were to isolate a microorganism that could effectively reduce 1‐acetonaphthone (1‐ACN) to S‐NE, to determine the influence that the physicochemical parameters would have on the reduction by the isolated microorganism, and to attempt large‐scale studies with the microorganism. Over the years fungi have been considered a promising biocatalyst and it has been presumed that many fungal species have not been isolated and therefore the current study focused on possible isolation of these microorganisms. A total of 72 fungal isolates were screened for their ability to reduce 1‐ACN to its corresponding alcohol. The isolate, EBK‐62, identified as Alternaria alternata, was found to be the most successful at reducing the ketone to the corresponding alcohol in the submerged culture. The reaction conditions were systematically optimized for the reducing agent A. alternata EBK62, which showed high stereospecificity and good conversion for the reduction. The preparative scale study was carried out in a 2 L bioreactor and a total of 4.9 g of S‐NE in optically pure form (>99% enantiomeric excess) was produced in 48 h. Chirality 28:669–673, 2016. © 2016 Wiley Periodicals, Inc.  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