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The initiating ability of 2-cyano-2-propyl hydroperoxide in the oxidation reaction of cumene by molecular oxygen has been investigated and compared with the initiating ability of cumene hydroperoxide.
Die Initiierungseigenschaften von 2-Cyano-2-propyl-hydroperoxid bei Oxydations-prozessen
Zusammenfassung Es wurde die Initiierungsfähigkeit des 2-Cyan-2-hydroperoxypropans in der Oxidation von Cumol mit molekularem Sauerstoff untersucht und mit der Initiierungsfähigkeit des Cumolhydroperoxids verglichen.相似文献
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Liu Y Xiao XY Sun M Hu YH Ou-Yang KQ Cai SX Hua ZC 《Applied biochemistry and biotechnology》2006,133(1):77-86
Interleukin (IL)-2 is a pharmacologically important cytokine secreted by T-lymphocytes. Recombinant IL-2 (rIL-2) has been
modified and produced in many systems. Mass production of rIL-2 is the prerequisite for its wide application. Using a site-directed
mutagenesis strategy, we first generated a gene coding for a new type of mutant of human IL-2 (MhIL-2), in which we replaced
the cysteine-125 in human IL-2 with alanine, the leucine-18 with methionine, and the leucine-19 with serine. Then we investigated
the possibility of its production of MhIL-2 in a Pichia pastoris system. High-level secreted expression of MhIL-2 was achieved by methanol induction. When purified with ultrafiltration,
cation-exchange chromatography, and Sephadex G100 gel filtration, about 100 mg of MhIL-2 with high purity was obtained from
1 L of ferment supernatant. Biologic activity assay revealed that the purified recombinant protein displayed increased activity
on proliferation of IL-2-dependent CTLL-2 cells. These results suggest that MhIL-2 is an improved IL-2 mutant that might hold
great promise for clinical use, and that P. pastoris is an excellent system for the mass production of biologically active hIL-2. 相似文献
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有关荧光素的溴和碘取代物的低温磷光性质与取代度关系的研究表明,随着取代度的增大,磷光量子产率与荧光量子产率之比呈现先增大继而减小的趋势,即溴和碘的充分取代物的磷光反而减弱,故用eosin-ITC作标记物的报道很少.化学结构和环境等因素对磷光发射有重要影响;某些已被重原子(Br或/和I)高度取代的试剂, 相似文献
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Maria Antonieta Ferrara Josiane M. V. Mattoso Elba P. S. Bon Nei Pereira Jr. 《Applied biochemistry and biotechnology》2004,113(1-3):299-305
Although the quality of nitrogen source affects fermentation product formation, it has been managed empirically, to a large
extent, in industrial scale. Laboratory-scale experiments successfully use the high-cost proline as a nonrepressive source.
We evaluated urea as a substitute for proline in Saccharomyces cerevisiae ure2dal80 fermentations for asparaginase II production as a model system for nitrogen-regulated external enzymes. Maximum asparaginase
II levels of 265 IU/L were observed in early stationary-phase cells grown on either proline or urea, whereas in ammonium cells,
the maximum enzyme level was 157 IU/L. In all cases, enzyme stability was higher in buffered cultures with an initial pH of
6.5. 相似文献
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[2+2+2] Cycloaddition reaction is a captivating process that assembles six-membered rings from three unsaturations with complete atom economy. Of the multiple transition metals that can be used to catalyze this reaction, rhodium offers many advantages. These include high activity and versatility, but especially the ability to easily tune the reactivity and selectivity by the modification of the ligands around the metal. In this personal account, we summarize our endeavours in the development of efficient and sustainable [2+2+2] cycloaddition reactions to prepare products of interest, develop conditions in which the catalyst can be recovered and reused, and understand the mechanistic details that govern the selectivity of the processes. 相似文献
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Cu2+/TiO2对甲基橙的光催化降解机理 总被引:11,自引:1,他引:10
以自制的掺铜离子的混晶型二氧化钛为光催化剂,考察了甲基橙光催化降解过程中pH值和光源的影响,提出了两种不同的光催化降解机理:在高压汞灯照射下,TiO2的价带电子被激发到导带,光生电子和空穴主要通过Cu2+ 的短路循环而复合,光催化剂的活性降低;在太阳光照射下,甲基橙发生自身光敏化氧化反应,受激电子从单线态或三线态的甲基橙分子跃迁到TiO2的导带,Cu2+起到电荷传递中继站的作用,加速了注入电子向H2O2的转移,从而促进了甲基橙的光催化降解。 相似文献
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Jingjing Li Letong Yin Jingxiu Bi David Stanley Qili Feng Qisheng Song 《Molecules (Basel, Switzerland)》2022,27(18)
The transforming growth factor-β (TGF-β) superfamily encodes a large group of proteins, including TGF-β isoforms, bone morphogenetic proteins and activins that act through conserved cell-surface receptors and signaling co-receptors. TGF-β signaling in insects controls physiological events, including growth, development, diapause, caste determination and metamorphosis. In this study, we used the red flour beetle, Tribolium castaneum, as a model species to investigate the role of the type I TGF-β receptor, saxophone (Sax), in mediating development. Developmental and tissue-specific expression profiles indicated Sax is constitutively expressed during development with lower expression in 19- and 20-day (6th instar) larvae. RNAi knockdown of Sax in 19-day larvae prolonged developmental duration from larvae to pupae and significantly decreased pupation and adult eclosion in a dose-dependent manner. At 50 ng dsSax/larva, Sax knockdown led to an 84.4% pupation rate and 46.3% adult emergence rate. At 100 ng and 200 ng dsSax/larva, pupation was down to 75.6% and 50%, respectively, with 0% adult emergence following treatments with both doses. These phenotypes were similar to those following knockdowns of 20-hydroxyecdysone (20E) receptor genes, ecdysone receptor (EcR) or ultraspiracle protein (USP). Expression of 20E biosynthesis genes disembodied and spookier, 20E receptor genes EcR and USP, and 20E downstream genes BrC and E75, were suppressed after the Sax knockdown. Topical application of 20E on larvae treated with dsSax partially rescued the dsSax-driven defects. We can infer that the TGF-β receptor gene Sax influences larval-pupal-adult development via 20E signaling in T. castaneum. 相似文献
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本文详细地综述了最近几年来有关超临界CO2流体中的化学反应的研究成果,展望了超临界CO2化学反应的开发应用前景,试图让这一崭新的研究领域受到更加广泛的关注。 相似文献