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991.
Summary A simple assay is described for the quantitative measurement of cellulase and hemicellulase activities. It is based on the enzymatic release of stained cleavage products originating from dyed substrates such as different celluloses, mannan and xylan, diffusing from an upper into a lower agar layer. The amount of cleavage products is assessed by direct absorbance measurement in the agar tubes employing an ordinary filter photometer. The method proved to be applicable to various species of basidiomycete fungi. 相似文献
992.
The chlorinated ethylenes 1,1-dichloroethylene (vinylidene chloride), trans-1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene (perchloroethylene) were assayed for their ability to induce mitotic gene conversion and point mutation as well as mitotic aneuploidy in diploid strains of the yeast Saccharomyces cerevisiae. From strain D7 late logarithmic-phase cells grown in 20% glucose liquid medium, containing a high level of cytochrome P-450, as well as stationary-phase cells combined with an exogenous metabolic activating system (S9) were used, in order to activate the chlorinated compounds and to produce electrophilic mutagenic intermediates. Only 1,1-dichloroethylene exhibited a dose-dependent genetic activity, while the other ethylenes did not. The 2 ways of metabolic activation were compared and were found to cause approximately the same effect. In contrast to the findings with strain D7, vinylidene chloride, trans-1,2-dichloroethylene, and trichloroethylene induced, without metabolic activation, mitotic chromosomal malsegregation in strain D61.M. The presence of liver homogenate as an activating system did not enhance the respective frequencies of chromosome loss. In the case of tetrachloroethylene, sufficient data have not become available, since this compound showed a highly toxic effect towards yeast cells, decreasing the rate of surviving cells to less than 30% at a concentration of 9.8 mM. 相似文献
993.
E L Elfahime M Plante F René J M Fe?ix B Koch 《The Journal of steroid biochemistry and molecular biology》1992,41(2):135-140
The present study reports on the ontogeny and the effect of thyroid hormones on liver corticosteroid-binding globulin (CBG) biosynthesis, in relation to plasma CBG binding capacity in the rat. We show that mRNACBG contents were high in liver of 18-day-old fetuses and decreased with age to reach almost undetectable levels by postnatal day 1. Interestingly, at the latter time point plasma CBG concentration remained elevated and disappeared thereafter from the circulation with a half-life of about 3 days. The messenger was localized in parenchymatous cells and not in hematopoietic ones, although the latter constitute the major cell population in fetal liver. It is not until after 10 days of age that mRNACBG and plasma CBG levels increased in concert, with a sex-difference being noticed by postnatal day 30. Treatment of rats with 3,3',5-triiodo-L-thyronine (T3), but not reverse T3 (rT3) (the predominant form present in fetal serum), enhanced CBG biosynthesis. These findings show that liver mRNACBG contents undergo dramatic changes during ontogeny and suggest the existence of a differential regulation of the messenger in fetal and neonatal rats. 相似文献
994.
X P Lu K S Koch D J Lew V Dulic J Pines S I Reed T Hunter H L Leffert 《The Journal of biological chemistry》1992,267(5):2841-2844
Cyclins and cyclin-associated cdc kinases are key regulators of oocyte maturation (Maller, J. L. (1990) in The Biology and Medicine of Signal Transduction (Nishizuka, Y., Endo, M., and Tanaka, C., eds) pp. 323-328, Raven Press, New York), yeast cell cycles (Nurse, P. (1990) Nature 344, 503-508), DNA replication in cell-free systems (D'Urso, F., Marraccino, R. L., Marshak, R. R., and Roberts, J. M. (1990) Science 250, 786-791), and amphibian cell proliferative transitions (Hunt, T. (1991) Nature 350, 462-463). The extent to which these regulatory molecules participate in the growth control of differentiated epithelial cells like hepatocytes is unknown. Therefore, we investigated the expression of "G1" (E, C, and D) and "G2/M" (A, B1, and B2) cyclin mRNAs, the relative levels of cyclin A- and B1-associated histone H1-kinase activity, and the appearance of cyclin-associated kinases (p32/p33cdk2 and p33/p34cdc2) in regenerating rat liver and in control tissues from sham hepatectomized rats. To do this, we exploited a battery of human cyclin cDNAs and cyclin antisera that recognize rat molecules. The results suggest an apparent sequence of regeneration-specific changes: 1) elevated and induced expression of cyclins E (2.1 kilobases (kb)) and C (4 kb), and D mRNAs (4 kb), within 12 h, respectively; 2) induction of cyclins A (3.4 and 1.8 kb), B1 (2.5 and 1.8 kb), and B2 (1.9 kb) mRNAs at 24 h; 3) induction of cyclin A- and B1-associated nuclear histone H1 kinase at 24 h; and 4) enhanced levels of PSTAIRE-containing proteins of Mr approximately 32-33 and 33-34 kDa in nuclear extracts from 24-h regenerating liver that co-immunoprecipitate with cyclin A and B1 antisera, respectively. These observations provide an intellectual framework that unifies the biology of hepatocyte mitogenesis, proto-oncogene expression, and the machinery of the cell cycle. 相似文献
995.
Interleukin-6 production by murine B cells and B cell lines 总被引:1,自引:0,他引:1
996.
Effect of Fluorination on Skin Sensitization Potential and Fragrant Properties of Cinnamyl Compounds 下载免费PDF全文
Julie Charpentier Roger Emter Heinz Koch Dominique Lelièvre Xavier Pannecoucke Samuel Couve‐Bonnaire Andreas Natsch Agnes Bombrun 《化学与生物多样性》2018,15(4)
A series of three α‐ and three β‐fluorinated representatives of the family of cinnamate‐derived odorants (cinnamaldehyde ( 1 ), cinnamyl alcohol ( 2 ), and ethyl cinnamate ( 3 )) as used as fragrance ingredients is described. Olfactive evaluation shows that the fluorinated compounds exhibit a similar odor profile to their parent compounds, but the olfactive detection thresholds are clearly higher. In vitro evaluation of the skin sensitizing properties with three different assays indicates that α‐fluorination of Michael acceptor systems 1 and 3 slightly improves the skin sensitization profile. α‐Fluorocinnamyl alcohol 2b is a weaker skin sensitizer than cinnamyl alcohol 2a by in vitro tests and the fluorinated product drops below the sensitization threshold of the KeratinoSens® assay. On the other hand, β‐fluorination of compounds 1 – 3 results in highly reactive products which display a worsened in vitro skin sensitization profile. 相似文献
997.
Domenico Sergi Fiona M. Campbell Christine Grant Amanda C. Morris Eva-Maria Bachmair Christiane Koch Fiona H. McLean Aifric Muller Nigel Hoggard Baukje de Roos Begona Porteiro Mark V. Boekschoten Fiona C. McGillicuddy Darcy Kahn Phyllis Nicol Jonas Benzler Claus-Dieter Mayer Janice E. Drew Helen M. Roche Michael Muller Ruben Nogueiras Carlos Dieguez Alexander Tups Lynda M. Williams 《Genes & nutrition》2018,13(1):28
998.
H. Lu R. J. Bekker M. J. Grundeken P. Woudstra J. J. Wykrzykowska J. G. P. Tijssen R. J. de Winter K. T. Koch 《Netherlands heart journal》2018,26(5):263-271
Objectives
We sought to investigate angiographic indications for the use of the STENTYS technique and evaluated the long-term safety and clinical efficacy of the stent.Background
Coronary lesions involving complex anatomy, including aneurysmatic, ectatic, or tapered vessel segments often carry a substantial risk of stent malapposition. The self-apposing stent technique may reduce the risk of stent malapposition and therefore improve clinical outcomes.Methods
A total of 120 consecutive patients treated with the STENTYS stent were included (drug-eluting stent (DES) n?=?101, bare-metal stent (BMS) n?=?19). All lesions were scored for angiographic indications for the STENTYS stent, including aneurysms, ectasias, tapering, absolute diameters, bifurcation lesions, and saphenous vein grafts. Off-line quantitative coronary angiography analyses were performed pre-procedure and post-procedure. Five years follow-up was obtained including cardiac death, target vessel myocardial infarction (TV-MI), target vessel revascularisation, stent thrombosis, and the composite endpoint target vessel failure (cardiac death, TV-MI and target vessel revascularisation).Results
Angiographic indications for STENTYS use were aneurysm (30%), ectasia (19%), tapering (27%), bifurcation lesions (8%), and saphenous vein graft lesions (16%) and absolute diameters (22%). Mean maximal diameter was 4.51?±?0.99?mm. At 5?year follow-up target vessel failure rates were 24.1% in the total cohort (DES 22.8% vs. BMS 33%, p?=?0.26). Definite stent thrombosis rate was 3.8% at 5?year follow-up in this cohort with complex and high-risk lesions (DES 4.5% vs. BMS 0%, p?=?0.39).Conclusions
Angiographic indications for the use of the self-apposing stent were complex lesions with atypical coronary anatomy. Our data showed reasonable stent thrombosis rates at 5?year follow-up, considering the high-risk lesion characteristics.999.
Inorganic CsPbI3 Perovskite Coating on PbS Quantum Dot for Highly Efficient and Stable Infrared Light Converting Solar Cells 下载免费PDF全文
Xiaoliang Zhang Jindan Zhang Dibya Phuyal Juan Du Lei Tian Viktor A. Öberg Malin B. Johansson Ute B. Cappel Olof Karis Jianhua Liu Håkan Rensmo Gerrit Boschloo Erik M. J. Johansson 《Liver Transplantation》2018,8(6)
Solution‐processed colloidal quantum dot (CQD) solar cells harvesting the infrared part of the solar spectrum are especially interesting for future use in semitransparent windows or multilayer solar cells. To improve the device power conversion efficiency (PCE) and stability of the solar cells, surface passivation of the quantum dots is vital in the research of CQD solar cells. Herein, inorganic CsPbI3 perovskite (CsPbI3‐P) coating on PbS CQDs with a low‐temperature, solution‐processed approach is reported. The PbS CQD solar cell with CsPbI3‐P coating gives a high PCE of 10.5% and exhibits remarkable stability both under long‐term constant illumination and storage under ambient conditions. Detailed characterization and analysis reveal improved passivation of the PbS CQDs with the CsPbI3‐P coating, and the results suggest that the lattice coherence between CsPbI3‐P and PbS results in epitaxial induced growth of the CsPbI3‐P coating. The improved passivation significantly diminishes the sub‐bandgap trap‐state assisted recombination, leading to improved charge collection and therefore higher photovoltaic performance. This work therefore provides important insight to improve the CQD passivation by coating with an inorganic perovskite ligand for photovoltaics or other optoelectronic applications. 相似文献
1000.
A long term evaluation of differential potassium fertilization of a creeping bentgrass putting green