Triazole-linked analogue of deoxyribonucleic acid ((TL)DNA): design, synthesis, and double-strand formation with natural DNA

A new triazole-linked analogue of DNA ((TL)DNA) has been designed and synthesized using click chemistry. The chain elongation reaction using copper-catalyzed Huisgen cycloaddition was successful and gave the artificial oligonucleotide that formed a stable double strand with the complementary strand of natural DNA.     

碳酸盐碳,氧稳定同位素微量测试方法的研究

本文简要叙述了微量碳酸盐样品碳，氧稳定同位素测试对于古海洋学研究的重要性，着重介绍了该方法的原理，制样过程以及质谱测量，同时还介绍了微量测试几个方面的试验工作，并对影响微量测试的几种因素进行了探讨。     

Moisture driven aging mechanism of LiFePO4 subjected to air exposure

The impact of air exposure on LiFePO₄–C nanocomposites has been investigated at moderate temperature. We show here that the storage in 120 °C hot air for 30 days leads not only to the material delithiation but also to the formation of an amorphous ferric phosphate side-phase, accounting for 38% of the total iron. The formed phase is found to be partially hydrated, suggesting a water-driven aging mechanism and a proposed hypothetic formula: Li_xFePO₄(OH)_x. The side-phase displays new electrochemical activity but poor cyclability and the overall battery performance is thus deteriorated. The regeneration of pristine structure, together with the performance recovery can be achieved by a simple thermal treatment under inert atmosphere.     

Expanding the chemical space in practice: diversity-oriented synthesis

Diversity-Oriented Synthesis (DOS) aims to broaden the frontier of accessible collections of complex and diverse small molecules. This review endeavours to dissect the DOS concept through three elements of diversity: building block, stereochemistry, and skeleton. Recent examples in the literature that emphasize the efficient combinations of these elements to generate diversity are reported.     

石墨炉原子吸收法连续测定气溶胶中重金属

提出了用石墨炉原子吸收法连续测定气溶胶中六种重金属的方法.气溶胶样品经处理后,直接用石墨炉原子吸收法测定其中的铜、钴、镍、镐、铅和铬.其检出限在 1.9×10~(-12)～1.6×10~(-10)g,仪器的精密度(RSD)<6.1%,标准加入回收率为90.4%～106.5%,已用于大批气溶胶样品的测定,结果令人满意.     

Green synthesis of water splitting electrocatalysts: IrO2 nanocages via Pearson's chemistry

Highly porous iridium oxide structures are particularly well-suited for the preparation of porous catalyst layers needed in proton exchange membrane water electrolyzers. Herein, we report the formation of iridium oxide nanostructured cages, via a water-based process performed at room temperature, using cheap Cu₂O cubes as the template. In this synthetic approach, based on Pearson''s hard and soft acid–base theory, the replacement of the Cu₂O core by an iridium shell is permitted by the difference in hardness/softness of cations and anions of the two reactants Cu₂O and IrCl₃. Calcination followed by acid leaching allow the removal of residual copper oxide cores and leave IrO₂ hierarchical porous structures with outstanding activity toward the oxygen evolution reaction. Fundamental understanding of the reaction steps and identification of the intermediates are permitted by coupling a set of ex situ and in situ techniques including operando time-resolved X-ray absorption spectroscopy during the synthesis.

Hierarchical IrO₂ nanocages, easily synthesized in water at room temperature, are extremely active towards the oxygen evolution reaction. The formation mechanism is based on the difference in softness/hardness of the ions involved in the reaction.     

λ-卡拉胶有限水解物在蛋白质置换层析分离中的应用研究

λ－卡拉胶经过有限酸水解得到不同平均分子量的组分，选用平均分子量为21kDa的组分，作为蛋白质置换层析的置换制，用于纤维素酶的分离纯化。经过置换层析，使黑色葡萄状穗霉S607发酵液中难以通过常规的分子筛和离子交换层析分离的一个内切酶组分（EGⅢ）和一个β－葡萄糖苷酶组分得到较好的分离。     

PHOTOCATALYTIC HYDROGEN EVOLUTION FROM WATER SPLITTING UNDER VISIBLE LIGHT IRRADIATION ON NOVEL PHOTOCATALYST FULLENES-PVP-ZN_(0.999)NI(0.001)S

1. INTRODUCTION1. INTRODUCTIONOne of the most widely discussed subjects these days is the energy crisis, i.e. the oil shortage and the oil price rising, which encouraged us to research and develop new green energy-hydrogen energy in the 21st century. Therefore, hydrogen produced from water splittingwith photocatalyst has been extensively studied from the viewpoint of photo energy, such as solar energy conversion to chemical and electricity energy, and environmental concerns. To date, …     

Development and validation of a hydrophilic interaction chromatography-mass spectrometry assay for taurine and methionine in matrices rich in carbohydrates

A new procedure based on hydrophilic interaction chromatography coupled to tandem mass spectrometry (ionisation process by pneumatically assisted electrospray in negative ion mode), is developed and validated for the simultaneous determination of underivatised taurine and methionine in beverages rich in carbohydrates such as energy drinks. No initial clean-up procedure and no sample derivatisation are required. Satisfactory analysis was obtained on an Astec apHera NH2 (150 mm x 4.6 mm; 5 microm) column with methanol-water (60/40) as mobile phase. The method was validated in terms of specificity, detection limits, linearity, accuracy, precision and stability, using threonine as internal standard. The potential effects of matrix and endogenous amino acid content were also examined. The limits of detection in the beverage varied from 20 microg L(-1) for taurine to 50 micro L(-1) for methionine.