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   50篇
  免费   4篇
  2021年   1篇
  2017年   2篇
  2016年   4篇
  2015年   6篇
  2014年   5篇
  2013年   7篇
  2012年   7篇
  2011年   5篇
  2010年   3篇
  2008年   1篇
  2007年   1篇
  2006年   2篇
  2004年   1篇
  2003年   1篇
  2002年   2篇
  2001年   3篇
  1999年   3篇
排序方式: 共有54条查询结果,搜索用时 31 毫秒
1.
2.
3.
The objective of this study was to evaluate the effects of partially replacing dry ground corn with glycerin on ruminal fermentation using a dual-flow continuous culture system. Six fermenters (1,223 ± 21 ml) were used in a replicated 3x3 Latin square arrangement with three periods of 10 d each, with 7 d for diet adaptation and 3 d for sample collections. All diets contained 75% concentrate and three dietary glycerin levels (0, 15, and 30% on dry matter basis), totaling six replicates per treatment. Fermenters were fed 72 g of dry matter/d equally divided in two meals/d, at 0800 and 2000 h. Solid and liquid dilution rates were adjusted daily to 5.5 and 11%/h, respectively. On d 8, 9, and 10, samples of 500 ml of solid and liquid digesta effluent were mixed, homogenized, and stored at -20°C. Subsamples of 10 ml were collected and preserved with 0.2 mL of a 50% H2SO4 solution for later determination of NH3-N and volatile fatty acids. Microbial biomass was isolated from fermenters for chemical analysis at the end of each experimental period. Data were analyzed using the MIXED procedure in SAS with α = 0.05. Glycerin levels did not affect apparent digestibility of DM (P Lin. = 0.13; P Quad. = 0.40), OM (P Lin. = 0.72; P Quad. = 0.15), NDF (P Lin. = 0.38; P Quad. = 0.50) and ADF (P Lin. = 0.91; P Quad. = 0.18). Also, glycerin inclusion did not affect true digestibility of DM (P Lin. = 0.35; P Quad. = 0.48), and OM (P Lin. = 0.08; P Quad. = 0.19). Concentrations of propionate (P < 0.01) and total volatile fatty acids (P < 0.01) increased linearly and concentrations of acetate (P < 0.01), butyrate (P = 0.01), iso-valerate (P < 0.01), and total branched-chain volatile fatty acids, as well as the acetate: propionate ratio (P < 0.01) decreased with glycerin inclusion. Linear increases on NH3-N concentration in digesta effluent (P < 0.01) and on NH3-N flow (P < 0.01) were observed due to glycerin inclusion in the diets. Crude protein digestibility (P = 0.04) and microbial N flow (P = 0.04) were greater in the control treatment compared with the other treatments and responded quadratically with glycerin inclusion. Furthermore, the inclusion of glycerin linearly decreased (P = 0.02) non-ammonia N flow. Glycerin levels did not affect the flows of total N (P Lin. = 0.79; P Quad. = 0.35), and dietary N (P Lin. = 0.99; P Quad. = 0.07), as well as microbial efficiency (P Lin. = 0.09; P Quad. = 0.07). These results suggest that partially replacing dry ground corn with glycerin may change ruminal fermentation, by increasing total volatile fatty acids, and propionate concentration without affecting microbial efficiency, which may improve glucogenic potential of beef cattle diets.  相似文献   
4.
Cyclodextrin (CD) is a well known drug carrier and excipient for enhancing aqueous solubility. CDs themselves are anticipated to have low membrane permeability because of relatively high hydrophilicity and molecular weight. CD derivatization with 17-beta estradiol (E2) was explored extensively using a number of different click chemistries and the cell membrane permeability of synthetic CD–E2 conjugate was explored by cell reporter assays and confocal fluorescence microscopy. In simile with reported dendrimer–E2 conjugates, CD–E2 was found to be a stable, extranuclear receptor selective estrogen that penetrated into the cytoplasm.  相似文献   
5.
Quantitative ethnobotany of two east Timorese cultures   总被引:1,自引:0,他引:1  
This is the first time aspects of the ethnobotany of East Timor have been reported. The medicinal plant traditions of two distinct East Timorese cultures, the Laklei and Idate, were studied and compared using quantitative ethnobotanical methods. A total of 86 medicinal plant species were identified. The medicinal plant traditions of the Laklei and Idate cultures were compared using Trotter and Logan’s (1986) quantitative “informant agreement ratio.” On average, informant consensus was greater in Laklei, suggesting a medicinal plant tradition that is more defined than in Idate, where informants are more likely to use the same medicinal plants when treating the same usage categories. Furthermore, only 11 of the 86 medicinal plant species documented were used by both cultures, of which only six had similar mentions. These findings have important implications for the understanding of ethnobotany as they demonstrate how relatively closely situated cultural groups can have significantly different traditional knowledge systems.  相似文献   
6.
Rabies virus (RV) is a highly neurotropic virus that migrates from the portal of entry to the central nervous system (CNS). The cytoplasmic dynein light chain (LC8), which is involved in a variety of intracellular motile events, was shown to interact with RV phosphoprotein (P). In order to determine the functional significance of this interaction, P residues 143 to 149 or 139 to 149 encompassing a conserved LC8-interacting motif (K/RXTQT) were deleted from recombinant viruses SAD-L16 and SAD-D29. These viruses are identical except for a replacement of the arginine at position 333 (R333) of the RV glycoprotein by an aspartic acid in SAD-D29. SAD-L16 virus is fully pathogenic for mice, whereas SAD-D29 is nonpathogenic for adult mice but retained pathogenicity for suckling mice. The deletions introduced into the LC8 binding site abolished the P-LC8 interaction and blocked LC8 incorporation into virions. All the mutants propagated in cell culture as efficiently as the parent strains. The pathogenicity of the mutants was then compared with that of the parent viruses by inoculating suckling mice. SAD-L16 derivatives were as pathogenic as their parent virus after intramuscular inoculation, indicating that LC8 is dispensable for the spread of a pathogenic RV from a peripheral site to the CNS. In contrast, SAD-D29-derived deletion mutants were attenuated by as much as 30-fold after intramuscular inoculation but remained as pathogenic as the parent virus when inoculated directly into the brain. This remarkable attenuation after intramuscular but not after intracranial inoculation suggested that abolishing the P-LC8 interaction reduces the efficiency of peripheral spread of the more attenuated SAD-D29 strain. These results demonstrate that elimination of the LC8 ligand and simultaneous substitution of R333 considerably attenuate RV pathogenicity and may be helpful in designing and developing highly safe live-RV-based vaccines.  相似文献   
7.

Introduction

The global burden of Tuberculosis (TB) remains enormous. Delay in TB diagnosis may lead to a higher infectious pool in the community and a more advanced disease state at presentation increasing the risk of mortality. This study is conducted to determine the total delay before treatment among smear positive Pulmonary Tuberculosis (PTB) patients.

Methods

A health institution based cross sectional study was conducted in five primary health centers in southern Ethiopia from June to December 2012. A total of 328 smear positive PTB patients were enrolled in the study. A structured and pre-tested questionnaire was used. Median patient, diagnostic, and treatment delays were calculated to determine the total delay. Multiple logistic regression analysis was used to identify factors associated with total delay.

Results

The median patient, diagnostic, treatment and total delays measured in days were 30 (IQR 20.2, 60), 7 (IQR: 3, 14), 3 (IQR: 1, 4) and 45 (IQR: 34.5, 69.5) days respectively. Patients for whom treatment was not initiated within 45 days of onset of symptom(s) (total delay) constituted 49% of the study participants (59.5% among males and 39.2% among females; P<0.001). Total delay was found to be associated with: being female [AOR  = 0.34, 95% CI: 0.18–0.62], having attended tertiary level education [AOR  = 0.11, 95% CI: 0.02–0.55], perceived severity of stigma during the current TB disease course [AOR = 2. 18, 95% CI: 1.07, 4.42] and living in houses with higher family size [AOR = 0.26, 95% CI: 0.11, 0.61].

Conclusion

Total delay in treatment of TB is still high in the study area. Patient''s sex, perceived stigma, educational status and family size are significantly contributing for total delay. Therefore, a concerted effort should be taken in order to improve health seeking behavior of the community on TB and to reduce delays from seeking care after experiencing TB symptoms.  相似文献   
8.
In recent years, diverse scholars have addressed the issue of the chemosensory perceptions associated with traditional medicines, nevertheless there is still a distinct lack of studies grounded in the social sciences and conducted from a cross-cultural, comparative perspective. In this urban ethnobotanical field study, 254 informants belonging to the Gujarati, Kashmiri and English ethnic groups and living in Western Yorkshire in Northern England were interviewed about the relationship between taste and medicinal perceptions of five herbal drugs, which were selected during a preliminary study. The herbal drugs included cinnamon (the dried bark of Cinnamomum verum, Lauraceae), mint (the leaves of Mentha spp., Lamiaceae), garlic (the bulbs of Allium sativum, Alliaceae), ginger (the rhizome of Zingiber officinale, Zingiberaceae), and cloves (the dried flower buds of Syzygium aromaticum, Myrtaceae). The main cross-cultural differences in taste perceptions regarded the perception the perception of the spicy taste of ginger, garlic, and cinnamon, of the bitter taste of ginger, the sweet taste of mint, and of the sour taste of garlic. The part of the study of how the five selected herbal drugs are perceived medicinally showed that TK (Traditional Knowledge) is widespread among Kashmiris, but not so prevalent among the Gujarati and especially the English samples. Among Kashmiris, ginger was frequently considered to be helpful for healing infections and muscular-skeletal and digestive disorders, mint was chosen for healing digestive and respiratory troubles, garlic for blood system disorders, and cinnamon was perceived to be efficacious for infectious diseases. Among the Gujarati and Kashmiri groups there was evidence of a strong link between the bitter and spicy tastes of ginger, garlic, cloves, and cinnamon and their perceived medicinal properties, whereas there was a far less obvious link between the sweet taste of mint and cinnamon and their perceived medicinal properties, although the link did exist among some members of the Gujarati group. Data presented in this study show how that links between taste perceptions and medicinal uses of herbal drugs may be understood as bio-cultural phenomena rooted in human physiology, but also constructed through individual experiences and culture, and that these links can therefore be quite different across diverse cultures.  相似文献   
9.
We report an efficient approach for the chemical synthesis of Rhesus θ-defensin-1 (RTD-1) using Fmoc-based solid-phase peptide synthesis in combination with an intramolecular version of native chemical ligation. The corresponding linear thioester precursor was cyclized and folded in a one-pot reaction using reduced glutathione. The reaction was extremely efficiently yielding natively folded RTD-1 with minimal or no purification at all. This approach is fully compatible with the high throughput production of chemical libraries using this peptide scaffold.  相似文献   
10.
Editing of P-gene mRNA of Newcastle disease virus (NDV) enables the formation of two additional proteins (V and W) by inserting one or two nontemplated G residues at a conserved editing site (5'-AAAAAGGG). The V protein of NDV plays an important role in virus replication and is also a virulence factor presumably due to its ability to counteract the antiviral effects of interferon. A recombinant virus possessing a nucleotide substitution within the A-stretch (5'-AAgAAGGG) produced 20-fold-less V protein and, in consequence, was impaired in replication capacity and completely attenuated in pathogenicity for chicken embryos. However, in a total of seven serial passages, restoration of replication and pathogenic capacity in 9- to 11-day-old chicken embryos was noticed. Determining the sequence around the editing site of the virus at passage 7 revealed a C-to-U mutation at the second nucleotide immediately upstream of the 5'-A(5) stretch (5'-GuUAAgAAGGG). The V mRNA increased from an undetectable level at passage 5 to ca. 1 and 5% at passages 6 and 7, respectively. In addition, similar defects in another mutant possessing a different substitution mutation (5'-AAAcAGGG) were restored in an identical manner within a total of seven serial passages. Introduction of the above C-to-U mutation into the parent virus (5'-GuUAAAAAGGG) altered the frequency of P, V, and W mRNAs from 68, 28, and 4% to 15, 44, and 41%, respectively, demonstrating that the U at this position is a key determinant in modulating P-gene mRNA editing. The results indicate that this second-site mutation is required to compensate for the drop in edited mRNAs and consequently to restore the replication capacity, as well as the pathogenic potential, of editing-defective NDV recombinants.  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