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排序方式: 共有960条查询结果,搜索用时 15 毫秒
951.
Pierre Conan Alice Lon Mathilde Gourdel Claire Rollet Loubna Chaïr Noline Caroff Nelig Le Goux Catherine Le Jossic-Corcos Maha Sinane Lucile Gentile Louise Maillebouis Nadge Loaëc Jennifer Martin Marie Vilaire Laurent Corcos Olivier Mignen Mikael Croyal Ccile Voisset Frdric Bihel Gaëlle Friocourt 《International journal of molecular sciences》2022,23(12)
CBS encodes a pyridoxal 5′-phosphate-dependent enzyme that catalyses the condensation of homocysteine and serine to form cystathionine. Due to its implication in some cancers and in the cognitive pathophysiology of Down syndrome, the identification of pharmacological inhibitors of this enzyme is urgently required. However, thus far, attempts to identify such molecules have only led to the identification of compounds with low potency and limited selectivity. We consequently developed an original, yeast-based screening method that identified three FDA-approved drugs of the 8-hydroxyquinoline family: clioquinol, chloroxine and nitroxoline. These molecules reduce CBS enzymatic activity in different cellular models, proving that the molecular mechanisms involved in yeast phenotypic rescue are conserved in mammalian cells. A combination of genetic and chemical biology approaches also revealed the importance of copper and zinc intracellular levels in the regulation of CBS enzymatic activity—copper promoting CBS activity and zinc inhibiting its activity. Taken together, these results indicate that our effective screening approach identified three new potent CBS inhibitors and provides new findings for the regulation of CBS activity, which is crucial to develop new therapies for CBS-related human disorders. 相似文献
952.
Anna Sannino Maria Rosaria Scarfì Mlody Dufosse Stefania Romeo Loredana Poeta Valerie Prouzet-Maulon Muriel Priault Olga Zeni 《International journal of molecular sciences》2022,23(15)
In the last years, radiofrequency (RF) has demonstrated that it can reduce DNA damage induced by a subsequent treatment with chemical or physical agents in different cell types, resembling the adaptive response, a phenomenon well documented in radiobiology. Such an effect has also been reported by other authors both in vitro and in vivo, and plausible hypotheses have been formulated, spanning from the perturbation of the cell redox status, to DNA repair mechanisms, and stress response machinery, as possible cellular mechanisms activated by RF pre-exposure. These mechanisms may underpin the observed phenomenon, and require deeper investigations. The present study aimed to determine whether autophagy contributes to RF-induced adaptive response. To this purpose, SH-SY5Y human neuroblastoma cells were exposed for 20 h to 1950 MHz, UMTS signal, and then treated with menadione. The results obtained indicated a reduction in menadione-induced DNA damage, assessed by applying the comet assay. Such a reduction was negated when autophagy was inhibited by bafilomycin A1 and E64d. Moreover, CRISPR SH-SY5Y cell lines defective for ATG7 or ATG5 genes did not show an adaptive response. These findings suggest the involvement of autophagy in the RF-induced adaptive response in human neuroblastoma cells; although, further investigation is required to extend such observation at the molecular level. 相似文献
953.
954.
月球车巡视探测的双目视觉里程算法与实验研究 总被引:2,自引:0,他引:2
月球车在月面巡视的移动距离测量是实现安全有效探测的重要保障.基于视觉里程计的定位方法是解决月面滑移,提高行驶里程推算精度的有效方法,对月球车实现高精度定位具有重要意义.本文对双目视觉里程算法的设计及实现技术进行了深入研究,并对基于不同特征提取算法的视觉里程定位方法进行了实验验证,通过与高精度全站仪数据比较,验证了算法的测量精度和有效性. 相似文献
955.
我国部分地区空气中氡及其子体α潜能浓度调查研究(1983—1990) 总被引:7,自引:0,他引:7
The Writing Group of the Summary Report on Nationwide Survey of Environmental Radioactivity Level in China 《辐射防护》1992,12(2):164-170,F003
本文报道1983—1990年由国家环境保护局组织的我国部分地区空气中氡及其子体α潜能浓度调查(试点)的方法和初步结果。全国15省选择21个城市以及部分特殊地点(包括部分煤渣砖房、人防工程地下室、海滨、水面和溶洞等)开展了此项调查。调查采用瞬时测量(有双滤膜法、闪烁法、气球法、活性炭吸附解析法)和累积测量(固体经迹蚀刻法)两种方法。考虑到长时间的平均浓度对评价氡吸入危害更有意义,并注意到我国北方农村特殊居室——窑洞和某些高寒城市肺癌发病率可能较高的情况,在调查后期,还组织了专门力量,用固体经迹探测器 CSR,对延安窑洞和哈尔滨居民室内氡浓度进行了测量。调查中室外测点尽量与大气常规监测同位,室内测点注意选取不同的建筑物类型。调查结果表明:(1)这些城市室外平均氡浓度均值范围为(3.3-40.8)Bq·m~(-3)子体α潜能浓度均值范围为(1.54—11.4)×10~(-8)J·m~(-3);(2)室内平均氡浓度范围为(7.5—170.8)Bq·m~(-3),子体α潜能浓度均值范围为(3.0—45.5)×10~(-8)J·m~(-3);(3)在武汉东湖、浙江千岛湖和辽宁大伙房水库三个水面,氡浓度均值分别为4.63、5.50和2.2 Bq·m~(-3),氡子体的等效平衡氡浓度均值分别为3.20、3.62和0.88 Bq·m~(-3),氡子体对水面上方空气吸收剂量率的贡献,分别为1.0、1 相似文献
956.
957.
The demultiplexing experiment from a 40 Gb/s optical time-division multiplexing signal is completed by using electro- absorption sampling window based on electronic phase-locked loop circuit for clock recovery. Error-free demultiplexing is achieved when the launched optical power into electro-absorption sampling window reaches 5.5 dBm without optical filter following the EDFA. 相似文献
958.
Vh-type crystals were prepared by precipitation in pure alcohol of amylose solutions in dimethyl sulfoxide (DMSO). The respective influences of amylose chain length and final equilibrium relative humidity (E.R.H.) on the nature of transitions induced by moisture exchanges were studied extensively using X-ray diffraction. The nature and kinetics of observed transitions depend on amylose chain length. If the Va form is always observed upon dehydration, A, B or mixtures of A and B forms are obtained according to the amylose chain length when rehydrating over higher water activities. Other specific transitions occurred when the Vh material was preliminary crystallized in mixture of ethanol and water (80/20,v/v). Some results suggest that these transitions occur through a transient disappearance of crystallinity and subsequent reorganization. Such mechanisms would be more conceivable than a solid state conversion from a single helical conformation (Vh type) to a double one (A and B types). 相似文献
959.
Four different starch sources, namely waxy maize, wheat, potato and pea starch were extruded with the plasticizer glycerol, the latter in concentrations of 15, 20 and 25% (w/w). The glass transition temperatures of the resulting thermoplastic products were measured by Dynamic Mechanical Thermal Analysis (DMTA). Beside mechanical and structural properties also the transition temperatures of the materials were evaluated during tensile and impact tests. Above certain glycerol contents, dependent on the starch source, a lower glass transition temperature Tg resulted in decreased modulus and tensile strengths and increased elongations. Lowering the Tg at different glycerol contents did not influence the impact strength. When the amylose/amylopectin ratio increased a decrease in Tg was found. For pea, wheat, potato and waxy maize starch the Tg was 75 °C, 143 °C, 152 °C and 158 °C, respectively. Therefore products with higher percentages of amylose are more flexible. The shrinkage of the specimens made by injection molding was considerable compared to the specimens made by pressing. 相似文献
960.
1996年,胜利油田微生物采油技术研究发展中心在开展微生物采油的室内试验和矿场研究中,取得突破性进展。在室内试验研究中,筛选、培养了适应于微生物采油的厌氧和兼性厌氧菌种80余株,分F、B两个系列,各12组,并具有年生产600t以上菌液的能力,菌液中的细菌密度达到1010~12Cel/L。在地层渗透率高于30×10-3μm2、地层矿化度低于150000mg/L、地层温度低于120℃、原油粘度低于4000mPa·s、含腊量高于3%的井中,用微生物进行吞吐处理均见到效果。1996年5月到年底,该中心先后在胜利、中原、滇黔桂等油田,矿场试验施工60余口井、230多井次,有效率达70%以上,累计净增原油8500多吨,取得很好的经济效益。因此,这项技术具有广阔的应用前景。 相似文献