Stabilization of zeylenone in rat plasma by the presence of esterase inhibitors and its LC‐MS/MS assay for pharmacokinetic study

Six esterase inhibitors, namely EDTA·2Na⁺, NaF, phenylmethanesulfonyl fluoride, dichlorvos, bis‐nitrophenyl phosphate (BNPP) and thenoyltrifluoroacetone, and the mixture of NaF and BNPP, were evaluated for the stabilization of labile benzoate containing zeylenone in rat plasma. The mixture appeared to exhibit the most effectively stabilizing effect with the degraded content of zeylenone decreasing from >60% (in the absence of inhibitors) to <6%. Following the stabilization by the addition of NaF (5 mm ) and BNPP (5 mm ), the analytes in rat plasma were acidified by formic acid and extracted into ethyl acetate at 0°C. After chromatographic separation, the detection of zeylenone was performed on a 3200 Q‐Trap with positive ion electrospray mode, monitoring the ion transition m/z 383.2 → 105.0. The method was validated over the range from 2.68 to 1340 ng/mL with inter‐ and intra‐run precision for the quality control samples being less than 6.8%. The assay accuracy was within 100 ± 7.0%. The validated method was successfully applied to a pharmacokinetic study in rats after the intratracheal administration of zeylenone in free drug or polymeric micellar solutions. The results showed that the pulmonary absorption of zeylenone loaded in micelles was significantly retarded compared with that of free drug solutions. Copyright © 2012 John Wiley & Sons, Ltd.     

A Rat’s Image Using Multichannel Phase Array RF Coil Specifically Designed for Animals: Focused on a Pulse Sequence and Mediator Variable

The study focuses on finding the pulse sequences depicting a rat’s tumor when the size of the field of view was reduced, using coils specifically designed for rats, and obtaining an optimized image of a rat by transforming the parameters, according to each pulse sequence. The manufactured coil is 8-channel phased array coils, and the type is a receive-only coil. The diameter of the coil is 80 mm, and the length is 150 mm. The overlapped distance among each channel was 8 mm, and the lab rats used in the experiment were the commonly used Sprague–Dawley rats. The study used three types of pulse sequences, which are the diffusion weight imaging (DWI), three-dimensional dual echo steady state (3-D DESS), and three-dimensional volumetric interpolated breath-hold (3-D VIBE). Along with the DWI results, pulse sequences of 3-D DESS and 3-D VIBE enabled to distinguish the tumors from that of normal tissues in the brain by optimizing a mediator variable and to illustrate the whole body imaging of a rat.     

浊点萃取-火焰原子吸收光谱法测定消食类中草药中的铅

建立了浊点萃取-火焰原子吸收光谱法测定4种消食类中草药中Pb含量的方法。以双硫腙为络合剂、非离子表面活性剂聚乙二醇辛基苯基醚(Triton X-100)为萃取剂,采用浊点萃取-火焰原子吸收光谱法联用,测定4种消食类中草药中Pb的含量,探讨溶液p H、表面活性剂用量、络合剂用量、平衡温度、平衡时间、干扰离子等条件对浊点萃取率的影响。最佳条件下,富集倍数为21倍,方法的检出限为0.16μg/L,校准曲线相关系数为0.9995;RSD≤1.7%(n=11),回收率在96.5%~98.1%之间。方法已用于4种消食类中草药中Pb的测定。     

Thermogravimetric analysis of carbide slag

Potential of carbide slag as transesterification catalyst is validated. Combined with X-ray fluorescence for ingredient determination, X-ray diffraction for textural phase analysis, scanning electron microscope for surface morphology observation and Hammett indicator for basic strength mensuration, thermal event of carbide slag is investigated through thermogravimetric analysis to estimate the potential of this calcium-based industrial waste as transesterification catalyst. Further, kinetic parameters are calculated through model-free method, where the experiments are conducted at temperature heating rates of 5, 10, 15, and 20 K min^?1. As for activation energy and reaction order, Vyazovkin method and Avrami theory are respectively mentioned. Meanwhile, catalytic performance of carbide slag is labeled by transesterification efficiency and calcium hydroxide is conditionally mentioned for comparison. In conclusion, potential of carbide slag as transesterification catalyst is adequately validated.     

Structural and functional stabilities of artificially designed DNA ultra-thin films grown by silica Assistance

We report the structural and functional stabilities of artificially synthesized DNA ultra-thin films. Fully covered DNA ultra-thin films on a silica substrate were fabricated by the silica-assisted growth method and those samples were then incubated in various chemicals and physical conditions. The DNA ultra-thin films showed high maintainability under those harsh conditions and these results would aid to facilitate the use of artificial DNA ultra-thin films in advanced research areas such as biophotonics and bioelectronics.     

采用金属有机骨架材料M(HBTC)(4,4'-bipy)·3DMF(M=Ni,Co,Zn)催化CO_2与环氧丙烷的环加成反应（英文）

采用溶剂热法合成了三种M(HBTC)(4,4’-bipy)·3DMF(M=Ni,Co,Zn,HBTC=1,3,5-均苯三甲酸,4,4’-bipy=4,4′-联吡啶)结构的支柱层金属有机骨架材料(MOFs).首次采用溶剂热和微波法合成了Zn(HBTC)(4,4’-bipy)·3DMF,并采用多种物理化学方法对其进行了表征.M(HBTC)(4,4’-bipy)·3DMF中包含有M2+离子的蜂窝网格层和BTC单元,BTC单元与4,4’-联吡啶柱进一步交联形成三维多孔骨架材料.在采用烷基铵卤化物作为助催化剂和无溶剂的条件下,所有MOFs材料均对催化固定CO_2与环氧化合物环加成制备环状碳酸酯反应表现出非常好的协同催化性能,其催化活性高低顺序为:ZnCoNi,这可通过酸-碱双功能特性进行解释.采用微波法合成的Zn(HBTC)(4,4’-bipy)·3DMF材料表现出与常规催化剂相似的物理化学性质和催化性能.考察了不同制备参数的影响和材料的重复使用性能,并提出了该反应的可能机理     

Fast,Scalable Synthesis of Micronized Ge3N4@C with a High Tap Density for Excellent Lithium Storage

Nanostructuring has significantly contributed to alleviating the huge volume expansion problem of the Ge anodes. However, the practical use of nanostructured Ge anodes has been hindered due to several problems including a low tap density, poor scalability, and severe side reactions. Therefore, micrometer-sized Ge is desirable for practical use of Ge-based anode materials. Here, micronized Ge₃N₄ with a high tap density of 1.1 mg cm⁻² has been successfully developed via a scalable wet oxidation and a subsequent nitridation process of commercially available micrometer-sized Ge as the starting material. The micronized Ge₃N₄ shows much-suppressed volume expansion compared to micrometer-sized Ge. After the carbon coating process, a thin carbon layer (≈3 nm) is uniformly coated on the micronized Ge₃N₄, which significantly improves electrical conductivity. As a result, micronized Ge₃N₄@C shows high reversible capacity of 924 mAh g⁻¹ (2.1 mAh cm⁻²) with high mass loading of 3.5 mg cm⁻² and retains 91% of initial capacity after 300 cycles at a rate of 0.5 C. Additionally, the effectiveness of Ge₃N₄@C as practical anodes is comprehensively demonstrated for the full cell, showing stable cycle retention and especially excellent rate capability, retaining 47% of its initial capacity at 0.2 C for 12 min discharge/charge condition.     

Effect of epistasis on the evolution of the quasi-species model

Epistasis is a phenomenon of non-additive interactions between genes in determining phenotypes. We investigate how epistasis affects the evolution of the quasi-species model by using the parallel mutation-selection (ParaMuSe) quasi-species evolution model. From the stochastic simulation of the ParaMuSe model, we find that there is a transition between the quasi-species with negative magnetization and the quasi-species with positive magnetization, depending on the peak value of each fitness region. The critical peak value for the transition is found to be larger than the equalpeak case so that even with a higher peak in the positive epistatic region, the quasi-species can be formed in the negative epistatic region. We analyze simulation results by using the coherent state representation for the ParaMuSe model and find that negative epistasis is favored to positive epistasis in forming more diverse quasi-species.

     

A deterministic channel access scheme for multimedia streaming in WiMedia networks

WiMedia MAC is an attractive transmission technology for high rate multimedia streaming and high quality consumer electronic devices in wireless personal area networks. In this paper, we propose a deterministic channel access (DCA), where all the devices determine their transmission orders in a distributed manner by exchanging beacon frames in the beacon period. Since all of the devices follow a deterministic transmission order, collision-free channel access can be achieved and thus the throughput can be significantly improved. In addition, the DCA addresses unfairness problems found in channel access by using circulating reference points. The trace-driven simulation results demonstrate that the DCA outperforms the existing channel access schemes in WiMedia MAC under different situations, especially under bursty traffic.