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排序方式: 共有668条查询结果,搜索用时 31 毫秒
41.
42.
Karim Samy El-Said Shaimaa Hussein Barakat M. Alrashdi Heba A. Mahmoud Mahrous A. Ibrahim Mohamed Elbakry Hala El-Tantawy Doaa Ibrahim Kabil Sabry A. El-Naggar 《Molecules (Basel, Switzerland)》2022,27(2)
Heavy metals intoxication causes several health problems that necessitate finding new protective and therapeutic approaches. This study aimed to evaluate the impact of Musa sp. leaves extract (MLE) on hepato-renal toxicities induced by cadmium (Cd) in male mice. The phytochemical screening, metal chelating activity (MCA), and the median lethal dose (LD50) of MLE were determined. Fifty CD-1 male mice were used and intraperitoneally (i.p.) injected with MLE (1000 to 5000 mg/kg b.wt) for MLE LD50 determination. Another 50 mice were used for evaluating the effect of MLE on Cd toxicity. Blood samples were collected for hematological, liver, and kidney functions assessments. Liver tissue homogenates were used for determination of oxidant/antioxidant parameters. Liver and kidney tissues were harvested for histopathological and molecular investigations. MLE showed potent in vitro antioxidant activities. The MCA and LD50 of the MLE were 75 µg/mL and 3000 mg/kg b.wt, respectively. MLE showed beneficial therapeutic activity against hepato-renal toxicities in Cd-intoxicated mice, evidenced by improving the hematological, biochemical, histopathological, and molecular alterations. 相似文献
43.
Prakasham RS Rao ChS Rao RS Rajesham S Sarma PN 《Applied biochemistry and biotechnology》2005,120(2):133-144
Optimization of alkaline protease production parameters by Bacillus sp. was investigated using Taguchi methodology. The pH of the medium was observed to be the most significant factor among
all selected optimization parameters at an individual level. The combinatorial influence of least significant factors, inoculum
level and salt solution concentration (at the individual level), resulted in an interacting severity index of 76%, suggesting
their interactive role in the regulation of protease production in this microbial species. Protease production could be improved
more than 100% with Taguchi’s optimized conditions of the medium composition by this microorganism. 相似文献
44.
Kariate Sudhakara Prasad A. B. Arun P. D. Rekha Chiu‐Chung Young Jen‐Lin Chang Jyh‐Myng Zen 《Electroanalysis》2009,21(14):1646-1650
Aerobically grown Shewanella sp. bacterial suspension drop‐coated on a disposable screen‐printed carbon electrode was found to possess electroactivity without the aid of redox mediator. Cyclic voltammetric studies revealed the characteristics of a mixed diffusion adsorption‐controlled electrochemical process for direct electron transfer at the bacteria‐modified electrode. Both FE‐SEM and ATR FT‐IR experiments were carried out to investigate the surface characteristics. The electroanalytical applicability was further demonstrated for electrocatalytic reduction of arsenite, hydrogen peroxide and nitrite. Low cost and very simple manufacturing procedure allow for the proposed bacterial sensor to be applied as disposable devices. 相似文献
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The evaluation of the use of alkaline peroxodisulfate digestion with low pressure microwave, autoclave or hot water bath heating for the determination of total phosphorus and nitrogen in turbid lake and river waters is described. The efficiency of these digestion procedures were compared to a Kjeldahl digestion procedure with sulphuric acid-potassium sulfate and copper sulfate. The final solution before digestion was 0.045 M in potassium peroxodisulfate and 0.04 M in sodium hydroxide. Procedures were evaluated by the analysis of suspensions of two reference materials, National Institute of Environmental Science, Japan, no. 3 Chlorella and no. 2 pond sediment and natural turbid waters. Best recoveries of phosphorus and nitrogen by microwave heating were obtained when solutions were digested at 95 °C for 40 min. Quantitative recoveries of phosphorus from Chlorella suspensions up to 1000 mg/l were obtained by all three heating procedures, but incomplete recoveries of nitrogen occurred above 20 mg N/l in the digested sample. Good recoveries of phosphorus and nitrogen from suspended sediment suspensions were obtained only from solutions containing <150 mg/l of suspended sediments. Recoveries of phosphorus from phosphorus compounds containing COP and CP bonds added to distilled water were quantitative (94-113%) except for polyphosphates (microwave, 34±8; autoclave, 114±6; water bath, 96±4) and aluminium phosphate (8-23%). Recoveries of nitrogen compounds containing CN bonds added to distilled water were quantitative (94-96%). The analysis of a range of natural turbid water samples by alkaline peroxodisulfate and microwave, autoclave and water bath heating gave similar total phosphorus and nitrogen results. All procedures using alkaline peroxodisulfate underestimate phosphorus concentrations at high suspended sediment concentrations (>150 mg/l) and are only suitable for the analysis of very turbid samples when the turbidity is due to organic matter (algal cells, plant detritus). Underestimation of nitrogen occurs when samples contain more than 20 mg N/l. 相似文献
48.
不动杆菌静息细胞催化拆分外消旋环戊酮醇乙酸酯反应条件的优化 总被引:4,自引:0,他引:4
考察了反应条件对不动杆菌Acinetobactersp.YQ231催化外消旋环戊酮醇乙酸酯对映选择性水解的反应速度和对映选择性的影响.确定的最佳酶反应条件为pH8.0,温度50℃.不同乳化剂对对映选择性的影响不同,以壬基酚聚氧乙烯醚的效果最好,当其加入量为15g/L时,反应的对映选择性最高.产物环戊酮醇对酶活性有显著的抑制作用.细胞中的酯酶优先水解(R)-环戊酮醇乙酸酯,生成(R)-环戊酮醇,在底物浓度为250mmol/L时,对映体比率(E值)可达50. 相似文献
49.
轰击离子能量对CNx薄膜中sp3型C-N键含量的影响 总被引:1,自引:0,他引:1
对磁控溅射生长在单晶Si(001)衬底上的CNx薄膜样品的化学键合及结构进行了研究,利用不同的衬底负偏压(Vh)来控制轰击衬底表面的入射离子能量,从而影响膜中的化学键合的状态.样品的FTIR,Ra-man和XPS分析结果表明,CNx薄膜中N原子分别与sp,sp2和sp3杂化状态的C原子结合,其中sp3型C-N键含量先随着衬底偏压(Vb)的升高而增加,并在偏压Vb=-50V时达到最大值,但随着Vb继续升高,sp3型C-N键含量减少,这表明CNx薄膜中,sp3型C-N键的含量与轰击离子的能量变化密切相关. 相似文献
50.
A New Perylenequinone from Hypomyces sp. 总被引:4,自引:0,他引:4
Wei Zhong LIU* Yun Xiu SHEN Xiang Feng LIU Yuan Teng CHEN Jin Lun XIE Chemistry Teaching Research Department Binzhou Medical College Binzhou Fermentation Engineering Key Laboratory Yunnan University Kunming 《中国化学快报》2001,(5)
Some metabolites of fungi and plants containing perylenequinones have been used as folk medicine for the treatment of many diseases1,2. A filamentous fungus, Ascomy-cetes Hypocreaceae Hypomyces (Fr.) Tul. sp., was found from the northwestern mountains of Yunnan Province, and cultured successfully in the laboratory. A new perylenequinone, named hypomycin A (1), was isolated from its mycelia. In this paper the structure elucidation of 1 was described. Figure 1 The structure of compound 1 Fig… 相似文献