Analysis of <Emphasis Type="Italic">O</Emphasis>-glycan heterogeneity in IgA1 myeloma proteins by Fourier transform ion cyclotron resonance mass spectrometry: implications for IgA nephropathy

IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis. In IgAN, IgA1 molecules with incompletely galactosylated O-linked glycans in the hinge region (HR) are present in mesangial immunodeposits and in circulating immune complexes. It is not known whether the galactose deficiency in IgA1 proteins occurs randomly or preferentially at specific sites. We have previously demonstrated the first direct localization of multiple O-glycosylation sites on a single IgA1 myeloma protein by use of activated ion-electron capture dissociation (AI-ECD) Fourier transform ion cyclotron resonance (FT-ICR) tandem mass spectrometry. Here, we report the analysis of IgA1 O-glycan heterogeneity by use of FT-ICR MS and liquid chromatography FT-ICR MS to obtain unbiased accurate mass profiles of IgA1 HR glycopeptides from three different IgA1 myeloma proteins. Additionally, we report the first AI-ECD fragmentation on an individual IgA1 O-glycopeptide from an IgA1 HR preparation that is reproducible for each IgA1 myeloma protein. These results suggest that future analysis of IgA1 HR from IgAN patients and normal healthy controls should be feasible.     

新型N-取代苯基-9-烷基-3-咔唑磺酰脲类化合物的合成及其抗肿瘤活性

以9-烷基咔唑为原料,经磺化、氯化和氨化反应制得9-烷基咔唑-3-磺酰胺(4a和4o);取代苯胺与三光气反应制得取代苯基异氰酸酯(6a~6n,6s,6Ⅳ);4分别与6经缩合反应合成了30个新型的N-取代苯基-9-烷基-3-咔唑磺酰脲类化合物(7a~7Ⅳ),其结构经1H NMR,IR和ESI-MS表征。对7进行了Cdc25B抑制活性筛选。结果表明,在用药浓度为20μg·m L-1时,其中12个化合物对Cdc25B具有良好的抑制活性,抑制率大于90%。     

Lelek?s problem is not a metric problem

We show that Lelek?s problem on the chainability of continua with span zero is not a metric problem: from a non-metric counterexample one can construct a metric one.     

Metal-molecule Schottky junction effects in surface enhanced Raman scattering

We propose a complementary interpretation of the mechanism responsible for the strong enhancement observed in surface enhanced raman scattering (SERS). The effect of a strong static local electric field due to the Schottky barrier at the metal-molecule junction on SERS is systematically investigated. The study provides a viable explanation to the low repeatability of SERS experiments as well as the Raman peak shifts as observed in SERS and raw Raman spectra. It was found that a strong electrostatic built-in field at the metal-molecule junction along specific orientations can result in 2-4 more orders of enhancement in SERS.     

掺镁钛酸钡纳米棒的水热合成和光催化性能

用水热法制备掺镁钛酸钡(Ba1-xMgxTiO3(x=0,0.10,0.20,0.30,0.40),BMT)纳米粉体。运用X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、紫外可见漫反射光谱技术(DRS)等手段对样品进行了表征,并在可见光照射下于溶液中考察了其光催化降解甲基橙反应活性。结果表明,通过控制氢氧根浓度可以得到不同形貌的纳米粉体。基于不同条件下制备的样品的微结构分析,提出了这些不同形貌的形成机制。制备出的BMT材料的带隙能约为2.61 eV。光催化反应结果表明BMT的光催化活性比掺氮TiO2高得多。OH-浓度为8 mol·L-1时制备的BMT纳米棒光催化效率最高,经可见光照射360 min,浓度为0.01 mmol·L-1甲基橙溶液的降解率可达到93.0%,且循环使用4次后,其光催化活性并没有明显降低,表明BMT是一种稳定有效的可见光催化剂.     

大岗山水电站防渗帷幕科研试验区的化灌设计与选材

针对四川大岗山水电站特殊的地质条件,采用YDS高渗透环氧化学灌浆材料,对Ⅴ1类辉绿岩脉开展水泥/化学复合灌浆的室内模拟试验和现场试验,分析灌浆参数、施工工艺、浆液扩散范围等有关技术问题,考察了化学灌浆的可行性,提出了合理的工艺参数。研究结果表明,YDS高渗透环氧化学灌浆材料灌浆与水泥灌浆组成的复合灌浆方式完全能够满足大岗山水电站防渗帷幕工程的要求,其化灌设计经济、合理,工艺操作可行,符合化学灌浆施工规范,现场试验效果满足设计要求。     

Quick detection of contaminants leaching from polypropylene centrifuge tubes with surface‐enhanced Raman spectroscopy and ultraviolet absorption spectroscopy

Anomalous surface‐enhanced Raman scattering (SERS) peaks were identified for liquid sample stored in polypropylene (PP) centrifuge tubes for months. We observed unexpected Raman peaks during experiments with thiamine hydrochloride aqueous solutions stored in PP tubes for 2 months. In order to identify the contaminants, we have performed SERS experiments on deionized (DI) water stored in PP centrifuge tubes for 2 months and compared them with those from fresh DI water sample. We have also carried out ultraviolet (UV) absorption spectra for both fresh and contaminated water. We believe that the water is contaminated because of chemicals leaching from the PP tube. From the gas chromatography‐mass spectrometry data, the main contaminants were found to be phthalic acid (PA) and its derivatives. Further SERS and UV absorption experiment for PA correlated well with the anomalous peaks identified earlier. We qualitatively confirmed the identification and quantitatively estimated the concentration of the suspect contaminants as between 1 and 10 µM with both SERS and UV absorption spectroscopy. With UV absorption spectroscopy, we precisely estimated the concentration as 2.1 µM . We have shown that the sample in PP tube can be contaminated by the leaching chemicals upon long‐term storage, and suggest SERS and UV absorption spectroscopy as two quick and simple techniques to detect the contamination. Copyright © 2011 John Wiley & Sons, Ltd.     

Two-channel Kondo physics in two-impurity Kondo models

We consider the non-Fermi-liquid quantum critical state of the spin-S two-impurity Kondo model and its potential realization in a quantum dot device. Using conformal field theory and the numerical renormalization group, we show the critical point to be identical to that of the two-channel Kondo model with additional potential scattering, for any spin S. Distinct conductance signatures are shown to arise as a function of device asymmetry, with the square-root behavior commonly believed to arise at low-energies dominant only in certain regimes.     

Af+AB星型聚合体系的统计热力学

应用统计力学和热力学原理研究了 A_f+AB星型聚合体系的性质. 首先从两种不同的角度给出了与聚合反应相应的配分函数, 并据此得到反应体系的平衡自由能、质量作用定律及数量分布函数, 进而得到了体系的平衡状态方程和比热. 在此基础上, 以反应体系的回转半径为例研究了溶剂效应对星型高分子空间尺度的影响.     

硫铝酸盐水泥复合调凝剂的制备及其性能研究

为了有效地控制硫铝酸盐水泥的凝结时间, 研究了不同掺量葡萄糖酸钠、柠檬酸钠、硫酸铝及氢氧化锂在复掺和混掺条件下对硫铝酸盐水泥凝结时间和工作性能的影响. 结果表明: 在以一定比例复合的柠檬酸钠和葡萄糖酸钠二相体系中, 再加入水泥质量1%～3%的硫酸铝或0.4%～1.5%氢氧化锂制成的三相调凝体系, 可以更灵活有效地控制快硬硫铝酸盐水泥的初凝结时间, 并可以更好地改善硫铝酸盐水泥的工作性能及常温体积安定性.