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61.
Kilian Dill Robert E. Hardy Ron L. Batstone-Cunningham Marsha E. Daman Bernard Ferrari André A. Pavia 《Carbohydrate research》1984,128(2):183-191
The pH dependence of the labeled-carbon resonances of reductively [13C] methylated compounds tri-l-Ser, glyco-octapeptide AM, asialoglyco-octapeptide AM, glyco-octapeptide AN, asialoglyco-octapeptide AN, and a glycopentapeptide was investigated. The results are discussed relative to those previously observed for reductively [13C]methylated, intact glycophorins AM and AN, and in terms of the mode of display of the MN blood-group specificities by these related glycoproteins. The results indicated that the α-d-NeuAc groups appear to affect the pH-titration results of glyco-octapeptides AM and AN. Moreover, comparison of the pH-titration results for reductively [13C]methylated glyco-octapeptide AM and reductively [13C]methylated asialoglyco-octapeptide AM with those of a reductively [13C]methylated glycopentapeptide and reductively [13C]methylated tri-l-Ser indicated that the other carbohydrate residues present (α-d-GalNAc and β-d-Gal) may also affect the pH-titration results. The reductive-methylation modification appears to affect the chemical shifts of the carbohydrate and peptide carbon atoms of the glycopentapeptide minimally. 相似文献
62.
Robert E. Hardy Marsha E. Daman Anne M. Holbrooks Kilian Dill 《International journal of biological macromolecules》1984,6(2):103-107
13C nuclear magnetic resonance (n.m.r.) spectral data for 13C reductively methylated N-terminal tryptic glycopeptides and for 13C reductively methylated N-terminal glyco-octapeptides derived from homozygous glycophorins AM and AN are presented. Their 13C chemical shift data are compared with the previously published 13C n.m.r. data for 13C reductively methylated homozygous glycophorins AM and AN in order to investigate the means of display of the MN blood determinants by these species. The pH dependence of the 13C resonances of leucine of glyco-octapeptide AN and of serine of glyco-octapepti AM indicated that only a slight structural perturbation occurs at the N-terminus when a large portion of the glycoprotein molecule is removed. However, one structural ‘state’ of 13C reductively methylated glycophorin AM is lost when the glyco-octapeptide AM is produced. The 13C resonance of leucine of glycooctapeptide AN titrated with a of 7.7 (Hill coefficient ). The 13C resonance of serine, on the other hand, exhibited an unusual pH dependence, indicating the existence of some possible steric constraints or hydrogen bonding in this molecule. In comparison to the data obtained for 13C-labelled glycooctapeptide AM molecule, the pH dependence of the chemical shift of the 13C resonance of serine of tripeptide tri-L-serine is also presented. Circular dichroism (c.d.) spectra indicated that the reductive methylation technique does not cause a large perturbation of the glycophorin A molecule. 相似文献
63.
Background
Mast cell-derived mediators mediate several of the pathological features of asthma. Microbial infections induce asthma exacerbations in which the contribution of mast cells remains incomprehensible.Principal Findings
In this study we have investigated the characteristic expression pattern of Toll-like receptors (TLRs) 1–9 and the effect of TLR ligand treatment on IgE-receptor mediated mast cell reactivity. For the studies we employed in vitro differentiated connective tissue like mast cells (CTLMC) and mucosal like mast cells (MLMC) from mice. Both phenotypes were treated for 24 h or 96 h with ligands for TLR1/2, TLR2/6, TLR3 and TLR4, before activation with IgE and antigen. Prolonged exposure (96 h) with TLR-ligands promoted mast cell reactivity following IgE-receptor activation. TLR4 activation with LPS generated the most pronounced effect, with an enhanced degranulation and secretion of leukotrienes, cytokines and chemokines, in both CTLMC and MLMC. The effect of LPS was mediated through a Myd88-dependent pathway and the increased effect involved JNK-dependent pathway.Conclusion
We find that prolonged exposure of mast cells to pathogens/TLR-ligands modulates their effector responses by priming them for increased release of several inflammatory mediators when subsequently activated by IgE-receptors. These data suggest that infections might exaggerate the severity of allergic reactions such as in asthma, by enhancing mediator release from mast cells. 相似文献64.
Ilona Rousalova Sulagna Banerjee Veena Sangwan Kristen Evenson Joel A. McCauley Robert Kratzke Selwyn M. Vickers Ashok Saluja Jonathan D’Cunha 《PloS one》2013,8(10)
Background
Minnelide, a pro-drug of triptolide, has recently emerged as a potent anticancer agent. The precise mechanisms of its cytotoxic effects remain unclear.Methods
Cell viability was studied using CCK8 assay. Cell proliferation was measured real-time on cultured cells using Electric Cell Substrate Impedence Sensing (ECIS). Apoptosis was assayed by Caspase activity on cultured lung cancer cells and TUNEL staining on tissue sections. Expression of pro-survival and anti-apoptotic genes (HSP70, BIRC5, BIRC4, BIRC2, UACA, APAF-1) was estimated by qRTPCR. Effect of Minnelide on proliferative cells in the tissue was estimated by Ki-67 staining of animal tissue sections.Results
In this study, we investigated in vitro and in vivo antitumor effects of triptolide/Minnelide in non-small cell lung carcinoma (NSCLC). Triptolide/Minnelide exhibited anti-proliferative effects and induced apoptosis in NSCLC cell lines and NSCLC mouse models. Triptolide/Minnelide significantly down-regulated the expression of pro-survival and anti-apoptotic genes (HSP70, BIRC5, BIRC4, BIRC2, UACA) and up-regulated pro-apoptotic APAF-1 gene, in part, via attenuating the NF-κB signaling activity.Conclusion
In conclusion, our results provide supporting mechanistic evidence for Minnelide as a potential in NSCLC. 相似文献65.
Acidophilic and alkalophilic cadmium-resistant bacterial strains were isolated from the metal-contaminated soil of Panki thermal power plant, Kanpur, India, and two strains, namely SB21 (acidophilic) and SB20 (alkalophilic), were selected as representative strains on the basis of their high resistance to cadmium as compared to other strains. The phylogenetic analysis of the strains using 16s rDNA sequence revealed the strains to be Pseudomonas putida and Comamonas species strain, respectively. Furthermore, to determine the mechanism involved in cadmium resistance, a czc gene was amplified from the strains and sequenced. Homology of the sequences of the two strains, when compared with the available database using a BLASTn search, showed that the 650bp amplicons possess a partial czcA gene sequence. Moreover, the mechanism was confirmed by the results of atomic absorption spectroscopy and transmission electron microscopy studies, which supported the efflux mechanism in the alkalophilic strain SB20, but the acidophilic strain SB21 showed intracellular and periplasmic accumulation of metal in the cells in spite of the presence of the czcA gene, indicating the presence of multiple mechanisms of metal resistance in strain SB21.
Further, the strains were characterized functionally for their bioremediation potential in cadmium-contaminated soil under acidic and alkaline conditions by performing an in-situ greenhouse experiment using mungbean plants. A marked increase in agronomical parameters was observed under acidic conditions in the presence of strain SB21. Moreover, the concentration of metal decreased in both plants and soil in the presence of these bioinoculants; however, strain SB21 was found to be a better decontaminator than SB20 and thus can further be employed in bioremediation applications. 相似文献
66.
Raghuwansh P. Sah Sushil K. Garg Ajay K. Dixit Vikas Dudeja Rajinder K. Dawra Ashok K. Saluja 《The Journal of biological chemistry》2014,289(40):27551-27561
The pathogenesis of chronic pancreatitis (CP) is poorly understood. Endoplasmic reticulum (ER) stress has now been recognized as a pathogenic event in many chronic diseases. However, ER stress has not been studied in CP, although pancreatic acinar cells seem to be especially vulnerable to ER dysfunction because of their dependence on high ER volume and functionality. Here, we aim to investigate ER stress in CP, study its pathogenesis in relation to trypsinogen activation (widely regarded as the key event of pancreatitis), and explore its mechanism, time course, and downstream consequences during pancreatic injury. CP was induced in mice by repeated episodes of acute pancreatitis (AP) based on caerulein hyperstimulation. ER stress leads to activation of unfolded protein response components that were measured in CP and AP. We show sustained up-regulation of unfolded protein response components ATF4, CHOP, GRP78, and XBP1 in CP. Overexpression of GRP78 and ATF4 in human CP confirmed the experimental findings. We used novel trypsinogen-7 knock-out mice (T−/−), which lack intra-acinar trypsinogen activation, to clarify the relationship of ER stress to intra-acinar trypsinogen activation in pancreatic injury. Comparable activation of ER stress was seen in wild type and T−/− mice. Induction of ER stress occurred through pathologic calcium signaling very early in the course of pancreatic injury. Our results establish that ER stress is chronically activated in CP and is induced early in pancreatic injury through pathologic calcium signaling independent of trypsinogen activation. ER stress may be an important pathogenic mechanism in pancreatitis that needs to be explored in future studies. 相似文献
67.
68.
Sharma Anket Kumar Vinod Shahzad Babar Ramakrishnan M. Singh Sidhu Gagan Preet Bali Aditi Shreeya Handa Neha Kapoor Dhriti Yadav Poonam Khanna Kanika Bakshi Palak Rehman Abdul Kohli Sukhmeen Kaur Khan Ekhlaque A. Parihar Ripu Daman Yuan Huwei Thukral Ashwani Kumar Bhardwaj Renu Zheng Bingsong 《Journal of Plant Growth Regulation》2020,39(2):509-531
Journal of Plant Growth Regulation - Plants encounter various abiotic stresses due to their sessile nature which include heavy metals, salt, drought, nutrient deficiency, light intensity, pesticide... 相似文献
69.
70.
Chatterjee M Saluja R Kumar V Jyoti A Kumar Jain G Kumar Barthwal M Dikshit M 《Free radical biology & medicine》2008,45(8):1084-1093
Previous studies from this lab have demonstrated that in vitro ascorbate augments neutrophil nitric oxide (NO) generation and oxidative burst. The present study was therefore undertaken in guinea pigs to further assess the implication of ascorbate deficiency in vivo on neutrophil ascorbate and tetrahydrobiopterin content, NOS expression/activity, phagocytosis, and respiratory burst. Ascorbate deficiency significantly reduced ascorbate and tetrahydrobiopterin amounts, NOS expression/activity, and NO as well as free radical generation in neutrophils from scorbutics. Ascorbate and tetrahydrobiopterin supplementation in vitro, though, significantly enhanced NOS catalysis in neutrophil lysates and NO generation in live cells, but could not restore them to control levels. Although phagocytic activity remained unaffected, scorbutic neutrophils were compromised in free radical generation. Ascorbate-induced free radical generation was NO dependent and prevented by NOS and NADPH oxidase inhibitors. Augmentation of oxidative burst with dehydroascorbate (DHA) was counteracted in the presence of glucose (DHA uptake inhibitor) and iodoacetamide (glutaredoxin inhibitor), suggesting the importance of ascorbate recycling in neutrophils. Ascorbate uptake was, however, unaffected among scorbutic neutrophils. These observations thus convincingly demonstrate a novel role for ascorbate in augmenting both NOS expression and activity in vivo, thereby reinforcing oxidative microbicidal actions of neutrophils. 相似文献