Analysis of rabbit tear proteins by high-pressure liquid chromatography/electrospray ionization mass spectrometry

The aim of this study was to develop a fast and reliable analytical procedure for the display of the protein components of tears that can be used to differentiate the status of the ocular surface. Using this new procedure, we analyzed the tear protein components following a corneal wound in the rabbit. Calibrated 10-microL glass, fire-polished capillary micropipettes were used to collect tears from New Zealand White rabbits prior to and daily for 9 days following a unilateral 6-mm diameter centrally placed anterior keratectomy. Tear proteins were eluted by a reversed-phase high-performance liquid chromatography (RP-HPLC) column and the tear protein profile was monitored by electrospray ionization (ESI) mass spectrometry positive total ion current (TIC) chromatography. Tear proteins were reliably separated into 17 peaks, each of which contained one or a number of protein components. The molecular weight of each protein component was determined by on-line ESI. Major tear protein components, lactoferrin, lysozyme (minimally detectable in rabbit tears), albumin, lipocalin, lipophilin and beta2-microglobulin, were tentatively identified by this method. Based on the mass spectrometric data, beta2-microglobulin was found to be glycosylated with N-acetylhexosamine. ESI-positive TIC chromatograms and mass spectra revealed comparative differences in the tear protein spectra after corneal wounding. One day after wounding, rabbit lysozyme with a molecular weight of 14,717 Da was found to be 8-fold higher in the tears of wounded eyes when compared with tears from unwounded eyes. It dropped back to normal 3 days after wounding. The expression of an unidentified tear protein with the molecular weight of 16,060 Da was also elevated after corneal wounding and returned to normal level by day 5. In this study, LC/ESI-MS was developed as a fast, reproducible and simple method for the identification and analysis of many of the protein components of the tears. Importantly, this technique also allows quantification of each component resolved in the chromatogram. This method is very suitable for mapping peptides and proteins (<80 kDa) in tears.     

N,N''''-硝基苯酰基取代苯酰氨基硫脲的合成与生物活性

酰氨基硫脲类化合物不仅具有广谱抗菌性能 ,还具有极好的杀虫和植物生长调节活性 [1～ 3] ,因而引起许多国内外学者对硫脲类化合物的合成及其化学结构与生物活性关系方面的研究 [4～ 8] .为了进一步研究不同的取代基团对此类化合物生物活性的影响 ,作者用硝基苯酰基异硫氰酸酯与芳基酰肼加成制得相应的 N ,N -硝基苯酰基取代苯酰氨基硫脲 ( ) ,并初步测定了它们抑制大肠杆菌和枯草杆菌生长的生物活性 .这些化合物尚未见文献报道 .Ar— COCl KSCN Ar—CONCS a～ cAr CONHNH2 ( 1 ～ 7) Ar—CONHC( S) NHNHCOAr Ar:a.o-N…     

Cure behavior of epoxy resin/MMT/DETA nanocomposite

The Flory's gelation theory, non-equilibrium thermodynamic fluctuation theory and Avrami equation have been used to predict the gel time t _g and the cure behavior of epoxy resin/organo-montmorillonite/diethylenetriamine intercalated nanocomposites at various temperatures and organo-montmorillonite loadings. The theoretical prediction is in good agreement with the experimental results obtained by dynamic torsional vibration method, and the results show that the addition of organo-montmorillonite reduces the gelation time t _gand increases the rate of curing reaction, the value of k, and half-time of cure after gelation point t_1/2 decreases with the increasing of cure temperature, and the value of n is ~2 at the lower temperatures (<60°C) and decreases to ~1.5 as the temperature increases, and the addition of organo-montmorillonite decreases the apparent activation energy of the cure reaction before gelation point, but has no apparent effect on the apparent activation energy of the cure reaction after gelation point. There is no special curing process required for the formation of epoxy resin/organo-montmorillonite/diethylenetriamine intercalated nanocomposite. This revised version was published online in July 2006 with corrections to the Cover Date.     

Further Daphniphyllum Alkaloids from the Leaves of Daphniphyllum macropodum Miq.

Five new polycyclic Daphniphyllum alkaloids, macropodumines F ( 1 ) and G ( 2 ), 17‐oxoyuzurimine ( 3 ), and macropodumines H ( 4 ) and I ( 5 ), were isolated from the leaves of D. macropodum Miq ., collected in Sichuan Province, China. The structures and relative configurations of the new compounds – as well as of four known, related alkaloids – were elucidated on the basis of in‐depth spectroscopic and mass‐spectrometric analyses, by chemical derivatization, and by comparison of spectroscopic data with those of known compounds.     

Studies of the electrochemical behavior of epinephrine at a homocysteine self-assembled electrode

The self-assembled electrode with the homocysteine monolayer (Hcy/Au) has been characterized by infrared spectroscopy and ac impedance spectroscopy in electrolyte. The Hcy/Au electrode is demonstrated to promote the electrochemical response of epinephrine (E) by cyclic voltammetry. A pair of well-defined redox waves was obtained and the calculated standard rate constant (k_s) is 2.1×10⁻² cm s⁻¹ at the self-assembled electrode. The reduction peak of E can be used to determine the concentration of E in presence of ascorbic acid (AA) owing to the Hcy/Au also promoting the electrochemical oxidation of AA.     

1—酰基—4—氯环己烷与取代芳烃的区域与立体选择性反应

从环己烯合成了１－酰基－４－氯环己烷，发现在其在ＡｌＣｌ３催化与苯，氯苯，溴苯等优先生成反式１－芳基－４－酰基环己烷，与联苯反应时选择性较差。     

Polyamide thin film composite membrane prepared from m-phenylenediamine and m-phenylenediamine-5-sulfonic acid

Thin film composite (TFC) membranes based polyamide were prepared with m-phenylenediamine (MPD), m-phenylenediamine-5-sulfonic acid (SMPD) and trimesoyl chloride (TMC) through interfacial polymerization technique on the polysulphone supporting film. The membranes were characterized using permeation experiments with salt water, attenuated total reflectance infrared (ATR-IR) and X-ray photoelectronic spectroscopy (XPS) as well as scanning electronic microscopy (SEM). This study has shown that the active layer of TFC membrane is aromatic polyamide, including sulfuric acid function group (-SO₃H) according to the result of ATR-IR and XPS. The NaCl rejection of RO membranes decreased and the flux increased when W_SMPD/W_MPD increased from 0 to 1, and the linear part with pendant -COOH in membrane barrier layer increased with the increase of SMPD content, but the surface of membrane becoming smoother and smoother with the increase of SMPD content. So the membranes performance mainly was determined by chemical structure in their barrier layer.     

聚芳醚砜薄膜的气体透过行为

研究了一系列聚芳醚砜的Ｈ２、ＣＯ２、Ｏ２、Ｎ２和ＣＨ４气体透过性能，讨论了其气体透过的温度依赖性。与双酚Ａ聚砜（ＰＳＦ）相比，几种新型聚芳醚砜的气体透过系数和气体选择系数同时有所提高。通过聚合物的分子链段活动性和自由体积数据系列变化，讨论了气体透过速率与分子结构的关系。     

单分散二氧化钛超微粒子的制备

以四丁氧基钛为原料，采用溶胶－凝胶法制备了超微二氧化钛粉末．改变热处理气氛、升温速率、水与四丁氧基钛的摩尔比以及溶剂，分别得到７ｎｍ球形单相锐钛矿以及四方形（４０ｎｍ×１０ｎｍ）、球形（４４ｎｍ）的主相金红石超微粒子．     

复合氨基酸微量元素螯合物制备新工艺的研究

本文报道了以废羽毛为原料，采用矿物质硫酸盐的制备与中和脱酸、螯合反应结合的新工艺，以金属盐类作催化剂和硫酸水解法，制得了复合氨基酸微量元素螯合物。复合氮基酸生成率为７１．７％，微量元素螯合率达到９８％以上。该工艺简单易行，生产成本低。