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   9篇
  免费   7篇
化学工业   8篇
建筑科学   1篇
轻工业   6篇
冶金工业   1篇
  2022年   1篇
  2021年   1篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2015年   2篇
  2014年   1篇
  2012年   1篇
  2011年   3篇
  2010年   1篇
  2007年   1篇
  1998年   1篇
排序方式: 共有16条查询结果,搜索用时 15 毫秒
11.
12.
Scope : The biological functions of caffeoylquinic acid (CQA) derivatives from various plant sources have been partially elucidated. The objectives were to isolate and purify diCQAs from Yerba mate tea leaves and assess their anti‐inflammatory and anti‐cancer capabilities in vitro and explore their mechanism of action. Methods and results : Methanol extracts of dried mate leaves were resolved by flash chromatography and further purified resulting in two fractions one containing 3,4‐ and 3,5‐diCQAs and the other 4,5‐diCQA with NMR‐confirmed structures. Both fractions inhibited LPS‐induced RAW 264.7 macrophage inflammation by suppressing nitric oxide/inducible nitric oxide and prostaglandin E2/cyclooxygenase‐2 pathways through inhibiting nucleus translocation of Nuclear factor κB subunits, p50 and p65. The diCQA fractions inhibited Human colon cancer cells CRL‐2577 (RKO) and HT‐29 cell proliferation by inducing apoptosis in a time‐ and concentration‐dependent manner, but did not affect the protein levels of p21, p27, p53, and Bax:Bcl‐2 ratio in RKO cells. In HT‐29 cells, however, the diCQA fractions increased Bax:Bcl‐2 ratio. The diCQA fractions increased the activation of caspase‐8 leading to cleavage of caspase‐3 in both RKO and HT‐29 colon cancer cells. Conclusion : The results suggest that diCQAs in Yerba mate could be potential anti‐cancer agents and could mitigate other diseases also associated with inflammation.  相似文献   
13.
Glycerol, a major by-product of biodiesel production, was employed as a fuel extender in this study. The process was originally investigated by etherifying the entire fluidized catalytic cracking (FCC) gasoline with glycerol. The reactions were carried out in a pressurized liquid phase reactor in the presence of three different catalysts (i.e. Amberlyst 16, Amberlyst 15, and β-zeolite) at 70 °C and 2.6 MPa with a volume ratio of FCC gasoline to glycerol ratio of 84:16 for 10 h. The catalytic activity could be ordered as Amberlyst 16 > Amberlyst 15 >> β-zeolite. The properties of FCC and etherified FCC products were determined by the standard analysis of Research Octane Number (RON), blending Reid vapor pressure (bRvp), distillation temperature following the standard methods of ASTM D-2699, ASTM D-5191 and ASTM D-86, respectively. It was found that the olefin content decreased opposing with increasing of octane number due to ethers of glycerol formation and the etherified gasoline product has lower bRvp than that of original FCC gasoline. The process of FCC gasoline etherification with glycerol showed great environmental benefits; in addition, ethers produced renewably from glycerol could extend the gasoline volume.  相似文献   
14.
The aim of this study was to investigate the relationship between dietary fish consumption and self-reported respiratory symptoms among young adults. A random sample of 4,300 subjects, aged 20-44 yrs, living in Bergen, Norway, received a postal questionnaire on respiratory symptoms, of whom 80% responded. Mean fish consumption was assessed in a food-frequency questionnaire by asking how often the subject consumed units of fish (150 g) during the last year. Average fish consumption was 1.8 units x week(-1). Fish intake of <1 unit x week(-1) was reported by 24%, 41% reported consumption of 1 unit x week(-1) and 35% intake of >1 unit x week(-1). A high fish intake was significantly associated with increasing age after adjusting for smoking. Adjusted for smoking habits, the prevalence of "cough at night" and "chest tightness" showed a decreasing trend with increasing fish consumption (p<0.05), while such a trend for "wheeze" was demonstrated only in smokers (p=0.008 for interaction). In logistic regression models (adjusting for age, sex, body mass, smoking habits and occupational exposure) fish consumption (three categories) was not significantly associated with "wheeze", "chest tightness", "breathless at night" or "asthma attack", although the odds ratios (OR) were consistently less than 1 (except for "asthma attack"). Fish consumption was of borderline significance as a protective factor of "cough at night", OR = 0.86 (95% confidence interval: 0.76-0.97) but in stratified analyses only in smokers. Subjects reporting very high levels of fish consumption (>14 units x week(-1)) did not have lower prevalences of respiratory symptoms. In conclusion, among young Norwegian adults, with a relatively low prevalence of asthma and an overall high fish intake, fish consumption was not a significant predictor of four out of five respiratory symptoms.  相似文献   
15.
Background: Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) play a critical role in neurodevelopment, where breast milk is a significant dietary source. The impact of previous COVID-19 infection and mastitis on the concentration of BDNF and NGF in human milk was investigated. Methods: Concentrations of BDNF and NGF were measured via ELISA in human milk samples collected from 12 mothers with a confirmed COVID-19 PCR, 13 mothers with viral symptoms suggestive of COVID-19, and 22 unexposed mothers (pre-pandemic Ctl-2018). These neurotrophins were also determined in 12 mothers with previous mastitis and 18 mothers without mastitis. Results: The NGF concentration in human milk was lower in the COVID-19 PCR and viral symptoms groups than in the unexposed group, but BDNF did not differ significantly. Within the COVID-19 group, BDNF was higher in mothers who reported headaches or loss of smell/taste when compared with mothers without the respective symptom. BDNF was lower in mothers with mastitis than in mothers without mastitis. Conclusions: Previous COVID-19 and mastitis infections changed differently the secretion of NGF and BDNF in human milk. Whether the changes in NGF and BDNF levels in milk from mothers with infection influence their infant’s development remains to be investigated.  相似文献   
16.
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