自制米袋在3.0T MRI颈部弥散序列扫描中的价值

目的:探讨自制米袋在3.0T MRI颈部弥散加权成像(Diffusion weighted imaging,DWI)序列扫描中的应用价值。方法:通过常规及米袋序列,用相同参数对50名志愿者颈部进行DWI扫描,对所得图像进行主观四级法及客观测量法评价,并比较分析。结果:50例志愿者主观评价法中,DWI图像质量分级在常规组和米袋组分别为30例和0例(1级)、15例和0例(2级)、5例和4例(3级)、0例和46例(4级),P均<0.05。客观评价法中,DWI图像在b值为200、400、600、800 s/mm^2时相位编码方向变形率平均值在常规组和米袋组分别为80.51±25.31和11.41±4.31、81.92±23.27和12.23±5.25、82.89±19.63和12.52±9.67,83.41±30.44和13.22±11.32,P均<0.05;结论:在3.0T MRI颈部DWI序列扫描中,应用米袋辅助扫描可明显提高成像质量,减少变形率,并且操作简单,易于推广。

Two Lower-barrier Channels in the Reaction of HF with HOBO

Two possible lower barrier reaction pathways in the reaction HF+HOBOH2O+FBO are predicated by means of MP2 and CCSD(T) (single-point) methods. In the two channels, two stable intermediates are located, and thus, they are multi-step channels, which are more favorable in energy than direct single-step reaction pathway predicated by previous theoretical study. Therefore, the two pathways should be main reaction channels in experiments.

Computer Simulation of Gd(III) Speciation in Human Interstitial Fluid

The speciation and distribution of Gd(III) in human interstitial fluid was studied by computer simulation. Meantime artificial neural network was applied to the estimation of log ?values of complexes. The results show that the precipitate species, GdPO4 and Gd2(CO3)3, are the predominant species. Among soluble species, the free Gd(III), [Gd(HSA)] , [Gd(Ox)] and then the ternary complexes of Gd(III) with citrate are main species and [Gd3(OH)4] becomes the predominant species at the Gd(III) total concentration of 2.2?0-2mol/L.

Study on the Enhancement of Proton Affinity by N-Diisopropyloxy Phosphorylation of Amino Acid in Mass Spectrometry

With introduction of a diisopropyloxy phosphoryl group into the N terminal of amino acids, it was found that proton affinity (PA) of amino acid was enhanced in mass spectrometry. Density functional theory calculations showed that the energy for protonation of DIPP-amino acid is lower than that of amino acid, which means PA of DIPP-AA is higher than that of corresponding amino acid. These results, coincident with our empirical results, offer a useful interpretation of experimental observations.

Preparation of Macroporous Poly (vinyl alcohol-co-triallyl isocyanurate) Beads Bearing Aminocarboxylic Acid as Functional Groups by Suspension Polymerization

Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Aminocarboxylic acids were immobilized on the copolymer beads by the esterification of hydroxyl groups with diethyl-lenetriaminepentaacetic bisanhydride. The weak acid exchange capacities, specific surface areas and mean pore diameters of the resultant resin beads were measured.

Indirect Determination of CTMAB with Sodium Chloride and Ammonium Thiocyanate by Floatation and Separation of Zinc

A new method for indirect determination of cetyl-trimethyl ammonium bromide (CTMAB) with NaCl and NH4SCN by floatation and separation of zinc has been studied. The study shows that Zn(II) can associate with NH4SCN and CTMAB to form insoluble ternary ion-association complex, and the precipitate can float on the surface of the liquid phase. A good linear relationship is observed between the floatation yield (E%) of Zn(II) and the amount of CTMAB. On the ground, CTMAB can be indirectly determined by determining E% of Zn(II). The results were satisfactory.

东西经济走廊——机遇之门

建立东西经济走廊（EWEC），是越南在1998年12月于菲律宾马尼拉举行的东盟高级首脑会议中倡议的，属于河内行动计划的一个部分。东西经济走廊（EWEC）全长1450公里，跨越了越南、老挝、泰国和缅甸四个国家，连接了太平洋与印度洋。它始于越南岘港，并一直延伸到缅甸的毛淡棉港。在东南亚地区大湄公河次区域（GMS）中，东西经济走廊有着最优先发展的权利。

一位画家的真故事和假故事

维梅尔(荷兰,1632-1675)的名画《带珍珠耳环的少女》,据考证创作于1660年,与伦勃朗的那幅著名自画像同年,其年维梅尔28岁,想必应该是风华正茂吧,待在一生未曾离开的代尔夫特,做他的小画商生意,别说欧洲,就是荷兰本土,听说过他的人也是寥寥可数;他的前辈伦勃朗那时54岁。