Application of thiophilic chromatography to deplete serum immunoglobulins in sample preparation for bidimensional electrophoresis

Serum is a typical sample for non-invasive studies in clinical research. Its proteome characterization is challenging, since requires extensive protein depletion. Methods used nowadays for removal of high-abundance proteins are expensive or show quite often a low loading capacity, which has strong repercussions on the number of samples and replicates per analysis.In order to deplete immunoglobulins (Igs) and albumin (HSA) from 1 mL serum samples, we have developed a protocol based on a combination of thiophilic chromatography, not previously used in clinical proteomics, and a HSA-specific resin. Ig/HSA-depleted samples, immunoglobulinome and albuminone were analyzed by 2-DE. Thiophilic chromatography, coupled with HSA-depletion, allows a good 2-DE resolution as well as the visualization of new spots. Moreover, it yields enough protein to evaluate technical variability and facilitate subsequent protein identification. To validate the protocol, we carried out a preliminary comparative study between triplicate Igs/HSA-depleted serum samples from healthy control individuals and recently diagnosed/untreated rheumatoid arthritis (RA) patients. RA patients showed several acute phase proteins, as well as additional serum proteins, differentially and significantly regulated.Therefore, thiophilic chromatography can be used as an efficient and economical method in 2-DE to deplete immunoglobulins from large human serum samples before a more extensive fractioning.     

硬质PVC/ACR共混体系的增韧机理研究

通过TEM、SEM等方法研究了不同结构丙烯酸酯类抗冲改性剂（ACR）对聚氯乙烯（PVC／ACR共混体系形态结构的影响,对ACR增韧硬质PVC的机理作了探讨,当PVC中含有8phr以上完善核壳结构的ACR时,在共混体系能形成网络结构,这一结构在受冲击时产生多重银纹,并实现银纹的纯化,在PVC／ACR共混体系的增韧机理中占主导地位,同时,ACR诱发PVC产生剪切形变也是提高其增韧效果的因素。     

Minimum SNR and acquisition for bias-free estimation of fractional anisotropy in diffusion tensor imaging - a comparison of two analytical techniques and field strengths

Although it is known that low signal-to-noise ratio (SNR) can affect tensor metrics, few studies reporting disease or treatment effects on fractional anisotropy (FA) report SNR; the implicit assumption is that SNR is adequate. However, the level at which low SNR causes bias in FA may vary with tissue FA, field strength and analytical methodology. We determined the SNR thresholds at 1.5 T vs. 3 T in regions of white matter (WM) with different FA and compared FA derived using manual region-of-interest (ROI) analysis to tract-based spatial statistics (TBSS), an operator-independent whole-brain analysis tool. Using ROI analysis, SNR thresholds on our hardware-software magnetic resonance platforms were 25 at 1.5 T and 20 at 3 T in the callosal genu (CG), 40 at 1.5 and 3 T in the anterior corona radiata (ACR), and 50 at 1.5 T and 70 at 3 T in the putamen (PUT). Using TBSS, SNR thresholds were 20 at 1.5 T and 3 T in the CG, and 35 at 1.5 T and 40 at 3 T in the ACR. Below these thresholds, the mean FA increased logarithmically, and the standard deviations widened. Achieving bias-free SNR in the PUT required at least nine acquisitions at 1.5 T and six acquisitions at 3 T. In the CG and ACR, bias-free SNR was achieved with at least three acquisitions at 1.5 T and one acquisition at 3 T. Using diffusion tensor imaging (DTI) to study regions of low FA, e.g., basal ganglia, cerebral cortex, and WM in the abnormal brain, SNR should be documented. SNR thresholds below which FA is biased varied with the analytical technique, inherent tissue FA and field strength. Studies using DTI to study WM injury should document that bias-free SNR has been achieved in the region of the brain being studied as part of quality control.     

NMR STUDY ON THE COMPATIBILITY OF ACR/PVC BLENDS

A 300MHz solid NMR study on the compatibility of ACR (poly (methyl methacrylate-co-methacrylate), in the ratio of 1:1)-PVC (poly (vinyl chloride)) blends is reported. Spin-lattice (T_1) and spin-spin (T_2) relaxation time of ACR, PVC and their blends are recorded in the temperature range from 215K to 355K. Experimental results indicate that ACR and PVC are compatible with each other and the domain size is smaller than 25 nm, but heterogeneit(?)s of molecular dimensions still exist. Some problems of mechanism of compatibility and data analysis are also discussed.     

支持IPTV业务的可控组播设计

根据大规模接入汇聚路由器(ACR)的总体结构,提出了一种支持IPTV业务的可控组播设计方案,从而满足IPTV业务的运营管理需求.     

5类电缆性能测试的基本指标

结构化布线工程的最后一步是对布线系统的测试和评估，电缆的性能测试经常被忽视，基本指标有：近端串扰，综合近端串扰，衰减串扰比，等效远端串扰，综合等效远端串扰，回波损耗，延迟抖动等。     

Alternative method for measurement of albumin/creatinine ratio using spectrophotometric sequential injection analysis

A simple, automatic and practical system for successive determination of albumin and creatinine has been developed by combining sequential injection analysis (SIA) and highly sensitive dye-binding assays. Albumin detection was based on the increase in the absorbance due to complex formation between albumin and eosin Y in acidic media. The absorbance of the complex was monitored at 547 nm. For the creatinine assay, the concentration of creatinine was measured by reaction with alkaline picrate to form a colored product which absorbs at 500 nm. The influences of experimental variables such as effects of pH, reagent concentration, standard/sample volume and interferences were investigated. Under optimal conditions, the automated method showed linearity up to 20 mg L⁻¹ for albumin and 100 mg L⁻¹ for creatinine. The 3σ detection limits were 0.6 and 3.5 mg L⁻¹ for albumin and creatinine, respectively, and the relative standard deviations (n = 10) were 2.49% for 20 mg L⁻¹ albumin, and 3.14% for 20 mg L⁻¹ creatinine. Application of the proposed method to the direct analysis of urinary samples yielded results which agreed with those obtained from the Bradford protein assay and a creatinine enzymatic assay according to a paired t-test. The results obtained should be a step towards developing a fully automated and reliable analytical system for clinical research, which requires direct determination of albumin and creatinine and/or its ratios.     

一种可承载IPTV的大规模接入汇聚路由器

提出了一种大规模接入汇聚路由器,使用光以太网点对点接入技术,把用户直接接入核心网络,可完整地承载IPTV业务.     

一种分布式星载单脉冲雷达GMTI方法

 提出了一种基于分布式星载单脉冲雷达的地面动目标检测方法,该方法充分利用星载分布式雷达主瓣和栅瓣回波的空时二维分布特点,能够在一次扫描（一个相干处理间隔）中有效地检测和分辨不同栅瓣杂波中的地面低速动目标,因此该方法不仅具有比一般分布式星载雷达处理更大的区域覆盖率和广域监视能力,具有较高的GMTI性能,且处理简单,运算量低,适合于星上实时处理。     

Solution to the problem of ant being stuck by ant colony routing algorithm

Many ant colony routing (ACR) algorithms have been presented in recent years, but few have studied the problem that ants will get stuck with probability in any terminal host when they are searching paths to route packets around a network. The problem has to be faced when designing and implementing the ACR algorithm. This article analyzes in detail the differences between the ACR and the ant colony optimization (ACO). Besides, particular restrictions on the ACR are pointed out and the three causes of ant being-stuck problem are obtained. Furthermore, this article proposes a new ant searching mechanism through dual path-checking and online routing loop removing by every intermediate node an ant visited and the destination host respectively, to solve the problem of ant being stuck and routing loop simultaneously. The result of numerical simulation is abstracted from one real network. Compared with existing two typical ACR algorithms, it shows that the proposed algorithm can settle the problem of ant being stuck and achieve more effective searching outcome for optimization path.