Alteration of yeast activity by gamma radiation

Yeast is an important component in microbe based industrial technologies. Due to the techno-economic reasons, the fermentation technique has acquired renewed interest. The effect of -radiation on the fermentation reaction has been investigated. The studies show that exposure of the fermentation mixture to -radiation at 5 kGy enhance alcohol production, whereas irradiation at higher doses, viz., 10 kGy and 25 kGy caused a considerable reduction in the alcohol yield. Therefore, low dose irradiation of fermentation mixtures can be applied for increasing the alcohol production by about 25%.     

甲烷无氧脱氢芳构化催化剂Mo/HZSM-5的研究

催化剂Ｍｏ／ＨＺＳＭ－５在甲烷地氧脱氢芳构化反应中表现出很高的活性，用ＸＲＤ，ＢＥＴ经表面，ＮＨ３－ＴＰＤ及ＴＰＲ等手段，对不抽提前后催化剂上的活性ｏ的种进行了研究，ＸＲＤ结果表明，Ｍｏ物种高度分散于筛表面，随着Ｍｏ担载量的提高，ＢＥＴ比表面积有所下降；但氨水抽提后，比表面积有很大程度的恢复，ＮＨ３－ＴＰＤ结果表明，Ｍｏ物种优先占据分子筛中的强酸位。ＴＰＲ结果显示出有ＭｏＯ３晶相存在的催化剂较易被     

Atmospheric pressure chemical ionization mass spectrometry of aldehydes in biological matrices

Application of high-performance liquid chromatography (HPLC) and tandem mass spectrometry (MS/MS) for detection of aldehydes in biological samples such as blood, yoghurt, and milk, is reported. Sample preparation is easy, and the presented method is both sensitive and selective. It is based on the widely used dinitrophenylhydrazine derivatization, followed by extraction with n-hexane and a simple reversed-phase HPLC separation. Detection is performed by atmospheric pressure chemical ionization (APCI) in negative ion mode, with detection limits in the low picogram range. Using MS/MS, acetone and propionaldehyde can clearly be distinguished, facilitating propionaldehyde quantitation even in the presence of high acetone levels. Quantitation by direct MS/MS is also feasible, well suited for high-throughput applications, although not as accurate as using HPLC/MS/MS.     

Theoretical study on the reaction mechanism and thermodynamics of tin oxidation by oxygen species and chlorine species

In this work ab initio molecular orbital methods were employed to study the coal combustion reaction mechanisms of tin oxidized by different oxidants, including HOCl, HCl, ClO, ClO₂, NO₃, CO₂, and O₂. Eleven reaction pathways were identified. The results show that Sn can react with HCl, ClOO, CO₂, O₂, and NO₃ to form SnO and SnCl. SnO can be oxidized into SnCl by HOCl and HCl. SnCl can be further oxidized into a soluble compound, SnCl₂. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

MESO-SUBSTITUTION REACTION OF ZINC OCTAETHYLPORPHYRIN VIA ANODIC OXIDATION

meso-Nitration, chlorination and acetoxylation of ZnOEP viaanodic oxidation are reported to proceed via EE'C, ECE and EE'C mechanismrespectively.     

Facile synthesis of oligophenylene-substituted calix[4]arenes and their enhanced binding properties

[reaction: see text] A facile and efficient protocol for the synthesis of oligophenylene OPP(n)-substituted calix[4]arenes (with n up to 4) via iodo-substituted oligoarylcalix[4]arenes has been developed. The cooperation effect of the proximate fluoroionophores in hexylsulfanyl end-capped OPP(n)-substituted calix[4]arene assemblies leads to metal ion binding enhancement.     

Impact of deglycosylation methods on two-dimensional gel electrophoresis and matrix assisted laser desorption/ionization-time of flight-mass spectrometry for proteomic analysis

Glycosylation is a common post-translational modification that can add complexity to the proteome of many cell types. We used enzymatic and chemical methods of deglycosylation to treat a heavily glycosylated exoproteome sample from the filamentous fungus Trichoderma reesei. Deglycosylated samples were resolved on one-dimensional (1-D) and two-dimensional (2-D) gels in order to determine the effect of deglycosylation on the electrophoresis patterns and on the ability to identify proteins by peptide mass matching using matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) analysis of in-gel tryptic digests. We found that deglycosylation of the protein sample resulted in different protein patterns on 1-D and 2-D gels, reduced the complexity of gel patterns, and enhanced the protein identification of some proteins via MALDI-TOF-MS. Deglycosylation with trifluoromethanesulfonic acid (TFMS) was found to be more effective than enzymatic treatments. These deglycosylation techniques may be employed in whole proteome analysis to locate glycosylated proteins and assist in their identification by MS.     

Electrochemistry in Organic Synthesis.: I. Large-Scale Preparation of Cysteine From Cystine

Cysteine hydrochloride was prepared by electroreduction of cystine with stainless steel plate as electrodes. 0.25 M of cystine in 1.5 N HC1 as cathode solution was divided by anion-exchange membrane from anode solution (1.5 N HC1). A current of 5.6 A/S was applied and at the end of reaction, crysteine hydrochloride was obtained by evaporation of the cathode solution. The method is more convenient than the existing method.     

Synthesis and Catalytic Studies of Uniform Os &; Os–Pd Nanoparticles Supported on MWNTs

Os and Os–Pd nanoparticles supported on multi-walled carbon nanotubes were prepared by vacuum pyrolysis at 573 K using the [Os₃CO₁₀(NCMe)₂] and [Pd(acac)₂] as precursors. The nanoparticles prepared showed a narrow size distribution (Os: 1.8 nm; Os–Pd: 4.3 nm) and were decorated evenly on the surface of the nanotubes. By controlling the metal-to-nanotube ratio, Os nanotubes were prepared using the carbon nanotubes as a template. The catalysis of Os–Pd nanoparticles towards CVD carbon nanotube synthesis was studied. Dedicated to Professor Gunther Schmid on the occasion of his 70th birthday.     

Substituted metal carbonyls. Part 25: Unidentate,intramolecular, and intermolecular bridging modes of 1,1′-bis(diphenylphosphino)ferrocene inM 3S2(CO)9 (M = Fe,Ru) cluster derivatives

Carbonyl exchange of Fe₃(₃-S)₂(CO)₉ wioth1,1-bis(diphenylphosphino)ferrocene (dppf) in refluxing THF gives a cluster ligand with a pendant phosphine moiety, Fe₃(₃-S)₂(CO)₈ (gn¹-Ph₂PlC₅H₄)Fe(C₅H₄)P⁴ MePh₂)]1 ^–,4. Addition of 1 to AuCl(SMe₂) gives ClAu(-dppf) Fe₄(₃-S)₂(CO)₈,8 (45%). Spectroscopic evidence is also obtained for (OC)₈ (₃-S)₂Fe₃(-dppf) Os₃(CO)₁₁,7 and PdCl₂[(-dppf)Fe₃(₃-D)₂(CO)₈]₂,9, from1 and Os₃(CO)₁₁(CH₃CN) and PdCl₂CN)₂, respectively. Crystal data dor3: space group P2₁/n,a = 10.891(3) Å,b = 19.939(3) Å,c = 20.443(2) Å, 100.17(2)°.Z = 4, 3917 reflections,R = 0.049.