Base free lithium-organoaluminate and the gallium congener: potential precursors to heterometallic assemblies

The first examples of base free lithium-organoaluminate and the corresponding gallium compound [LM(Me)OLi]3 (M = Al (3), Ga (4); L = HC{C(Me)N-2,6-iPr2C6H3}2) have been prepared by the reaction of Li[N(SiMe3)2] with the corresponding metal hydroxides LM(Me)OH (M = Al (1), Ga(2)); the oxygen atom in the M-O-Li fragment exists as oxide ion and is involved in the central Li3O3 six-membered ring formation.     

Elliptic flow for phi mesons and (anti)deuterons in Au+Au collisions at square root of sNN=200 GeV

Differential elliptic flow (v(2)) for phi mesons and (anti)deuterons (d)d is measured for Au+Au collisions at square root of sNN=200 GeV. The v(2) for phi mesons follows the trend of lighter pi+/- and K+/- mesons, suggesting that ordinary hadrons interacting with standard hadronic cross sections are not the primary driver for elliptic flow development. The v(2) values for (d)d suggest that elliptic flow is additive for composite particles. This further validation of the universal scaling of v(2) per constituent quark for baryons and mesons suggests that partonic collectivity dominates the transverse expansion dynamics.     

相对差商算法性能的统计研究

本文通过服从一致分布随机算例的均匀抽样方式，对离散变量优化问题的相对差商算法进行了数值实验，按启发式算法的性能评价指标对数值实验结果进行了统计分析，为评价相对差商算法的实际性能提供了统计依据     

Tetranuclear Uranyl Polyrotaxanes: Preferred Selectivity toward Uranyl Tetramer for Stabilizing a Flexible Polyrotaxane Chain Exhibiting Weakened Supramolecular Inclusion

Introduction of mechanically interlocked components into actinide‐based metal–organic materials such as polyrotaxanes will generate an entirely new type of inorganic–organic hybrid materials showing more supramolecular encapsulation‐based dynamics. In this work, tetranuclear uranyl‐directed polyrotaxanes (UO₂)₄O₂‐C5A3‐CB6 ( 1 ) and (UO₂)₄O₂‐C6A3‐CB6 ( 2 ), which are the first actinide pseudorotaxanes with high‐nuclearity uranium centers, were obtained through systematic extension of the string spacer in pseudorotaxane ligands from 1,4‐butylene (C4) to 1,5‐pentylene (C5) and 1,6‐hexylene (C6). Both of the as‐synthesized tetranuclear uranyl polyrotaxanes were structurally characterized and analyzed. Considering the structure of UO₂‐C4A3‐CB6 and the 1,4‐butylene string spacer, the preference for the uranyl tetramer may be related to the configurational inversion of the pseudorotaxane ligands from trans mode to cis mode on coordination to the uranyl center. Detailed structural analysis suggests that the length of the stretched string molecules for CB6 ‐encapsulated pseudorotaxanes has remarkable effect on the supramolecular inclusion interactions and the configurations of pseudorotaxanes, and should be responsible for the configurational inversion of pseudorotaxane spacers and subsequent distinct changes of the uranyl building units and geometric structures.     

Different transformation of carbosulfan to its higher toxic metabolites in pakchoi (Brassica campestris ssp.) and cucumber (Cucumissativus L.) after field application

Carbosulfan (CAS) is used as an insecticide on vegetables, but its toxicity might increase due to the formation of higher toxic metabolites including carbofuran (CAN), 3-hydroxycarbofuran (3-OH) and 3-ketocarbofuran (3-KETO). In this study, the transformation of CAS to its metabolites in pakchoi (Brassica campestris ssp.) and cucumber (Cucumissativus L.) was investigated in the field in Beijing and Changsha and in a greenhouse in Hangzhou. CAS was metabolised to CAN, 3-OH and 3-KETO in pakchoi but only to CAN and 3-OH in cucumber. In pakchoi, the degradation of CAS (as measured by the DT₅₀ value, the time marking the disappearance of 50% of the pesticide) was the fastest in Hangzhou (0.7 d), followed by Changsha (1.4 d) and Beijing (2.3 d), whereas in cucumber, its degradation was the fastest in Changsha (1.6 d) and Hangzhou (1.6 d), followed by Beijing (2.5 d). These results suggested the monitoring of metabolites should be a prior objective for CAS, and different metabolites should be considered when assessing the risk of CAS in different vegetables.     

Competitive proton and hydride transfer reactions via ion‐neutral complexes: fragmentation of deprotonated benzyl N‐phenylcarbamates in mass spectrometry

The gas‐phase chemistry of deprotonated benzyl N‐phenylcarbamates was investigated by electrospray ionization tandem mass spectrometry. Characteristic losses of a substituted phenylcarbinol and a benzaldehyde from the precursor ion were proposed to be derived from an ion‐neutral complex (INC)‐mediated competitive proton and hydride transfer reactions. The intermediacy of the INC consisting of a substituted benzyloxy anion and a phenyl isocyanate was supported by both ortho‐site‐blocking experiments and density functional theory calculations. Within the INC, the benzyloxy anion played the role of either a proton abstractor or a hydride donor toward its neutral counterpart. Relative abundances of the product ions were influenced by the nature of the substituents. Electron‐withdrawing groups at the N‐phenyl ring favored the hydrogen transfer process (including proton and hydride transfer), whereas electron‐donating groups favored direct decomposition to generate the benzyloxy anion (or substituted benzyloxy anion). By contrast, electron‐withdrawing and electron‐donating substitutions at the O‐benzyl ring exhibited opposite effects. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of sevoflurane on tight junction protein expression and PKC-α translocation after pulmonary ischemia–reperfusion injury

Pulmonary dysfunction caused by ischemia-reperfusion injury is the leading cause of mortality in lung transplantation. We aimed to investigate the effects of sevoflurane pretreatment on lung permeability, tight junction protein occludin and zona occludens 1 (ZO-1) expression, and translocation of protein kinase C (PKC)-α after ischemia–reperfusion. A lung ischemia-reperfusion injury model was established in 96 male Wistar rats following the modified Eppinger method. The rats were divided into four groups with 24 rats in each group: a control (group C), an ischemia-reperfusion group (IR group), a sevoflurane control group (sev-C group), and a sevoflurane ischemia-reperfusion group (sev–IR group). There were three time points in each group: ischemic occlusion for 45 min, reperfusion for 60 min and reperfusion for 120 min; and there were six rats per time point. For the 120-min reperfusion group, six extra rats underwent bronchoalveolar lavage. Mean arterial pressure (MAP) and pulse oxygen saturation (SpO₂) were recorded at each time point. The wet/dry weight ratio and lung permeability index (LPI) were measured. Quantitative RT-PCR and Western blot were used to measure pulmonary occludin and ZO-1, and Western blot was used to measure cytosolic and membranous PKC-α in the lung. Lung permeability was significantly increased after ischemia–reperfusion. Sevoflurane pretreatment promoted pulmonary expression of occludin and ZO-1 after reperfusion and inhibited the translocation of PKC-α. In conclusion, sevoflurane pretreatment alleviated lung permeability by upregulating occludin and ZO-1 after ischemia–reperfusion. Sevoflurane pretreatment inhibited the translocation and activation of PKC-α, which also contributed to the lung-protective effect of sevoflurane.     

Porous Liquids: A Promising Class of Media for Gas Separation

A porous liquid containing empty cavities has been successfully fabricated by surface engineering of hollow structures with suitable corona and canopy species. By taking advantage of the liquid‐like polymeric matrices as a separation medium and the empty cavities as gas transport pathway, this unique porous liquid can function as a promising candidate for gas separation. Moreover, such a facile synthetic strategy can be further extended to the fabrication of other types of nanostructure‐based porous liquid, opening up new opportunities for preparation of porous liquids with attractive properties for specific tasks.     

Acquired Superoxide‐Scavenging Ability of Ceria Nanoparticles

Ceria nanoparticles (nanoceria) are well known as a superoxide scavenger. However, inherent superoxide‐scavenging ability has only been found in the nanoceria with sizes of less than 5 nm and with very limited shape diversity. Reported herein is a strategy to significantly improve the superoxide‐scavenging activity of nanoceria sized at greater than 5 nm. The nanoceria with sizes of greater than 5 nm, with different shapes, and with a negligible Ce³⁺/Ce⁴⁺ ratio can acquire remarkable superoxide‐scavenging abilities through electron transfer. This method will make it possible to develop nanoceria‐based superoxide‐scavengers with long‐acting activity and tailorable characteristics.     

Hypercrosslinked Phenolic Polymers with Well‐Developed Mesoporous Frameworks

A soft chemistry synthetic strategy based on a Friedel–Crafts alkylation reaction is developed for the textural engineering of phenolic resin (PR) with a robust mesoporous framework to avoid serious framework shrinkage and maximize retention of organic functional moieties. By taking advantage of the structural benefits of molecular bridges, the resultant sample maintains a bimodal micro‐mesoporous architecture with well‐preserved organic functional groups, which is effective for carbon capture. Moreover, this soft chemistry synthetic protocol can be further extended to nanotexture other arene‐based polymers with robust frameworks.