Asymmetric cellulose acetate dialysis membranes: Synthesis,characterization, and performance

Cellulose acetate (CA) is highly comparable to other synthetic polymer materials and is effective in the hemodialysis process. In this work, asymmetric CA membranes were synthesized with the phase‐inversion method. CA with a molecular weight of 52,000, poly(ethylene glycol) (PEG) with a molecular weight of 400, and 1‐methyl‐2‐pyrrolidone (NMP) were used as the polymer, additive, and solvent, respectively. The effects of the CA and PEG concentrations and coagulation bath temperature (CBT) on the morphology, pure water permeability (PWP), insulin/human serum albumin (HSA) transmission, and finally thermal and chemical stability of the prepared membranes were determined and investigated. In general, increasing the PEG concentration and CBT and reducing the CA concentration resulted in increased PWP and insulin/HSA transmission. Also, these variations facilitated the formation of macrovoids in the membrane sublayer. On the other hand, increasing the PEG and CA concentrations and reducing CBT resulted in increased thermal and chemical stability of the prepared membranes. Also, ratios of 15.5/10/74.5 and 17.5/10/72.5 (w/w) for the CA/PEG/NMP casting solutions and their immersion into coagulation baths with CBTs of 0 and 25°C, respectively, resulted in the preparation of membranes that had not only optimum sieving properties and higher PWP but also thermal and chemical stability better than that of conventional CA hemodialysis membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Sulfuric acid recovery from rare earth sulphate solutions by diffusion dialysis

1 Introduction As an important industrial chemical, sulfuric acids are widely used in metallurgical and chemical processes, in which some waste solutions containing free sulfuric acids and metallic ions are therefore produced[1, 2]. If these waste acids …     

渗析法处理酸洗废液的膜面积

本文介绍了渗析地处理钢铁酸洗废液的原理，建立了计算渗析膜面积的公式，提出了渗析适宜条件是流入倍数为１．０５－１．２５，回收率为８０％－９０％。     

重组牛乳铁蛋白肽包含体的复性与纯化

通过分析透析液pH值，包含体蛋白浓度，DTT浓度3个参数对复性率的影响，确定了重组牛乳铁蛋白N-末端多肽（pGEX-4T1／rbLF—N）包含体透析复性的最佳条件和复性后蛋白纯化的适宜方法。采用谷胱甘肽琼脂糖凝肢4B柱（Glutathione Sapharose^TM 4B）时复性后的蛋白溶液进行纯化．纯化后的融和蛋白经胃蛋白酶酶解并检测其酶解产物的抗菌活性。试验表明包涵体蛋白可以部分复性。当pH值为8．5，包含体蛋白质量浓度为100mg／L，DTT浓度为24mmol／L，包含体的复性率最高。纯化后的融合蛋白酶解产物具有抗菌作用。     

一阶导数光谱法测定血液透析用浓缩物中醋酸根含量

建立一种测定血液透析用浓缩物中醋酸根含量的方法。方法：采用一阶导数光谱法测定血液透析用浓缩物中醋酸根的含量。波长扫描范围：190-300nm。结果：醋酸根线性范围是9．8-58．6mmol／L（r=0．9998）,平均加样回收率为99．9％,RSD=0．80％（n=3）。结论：此方法操作简便,测定时间短,准确度高,浓缩物中其他离子对测定结果基本无影响。     

应用FIAstar5000和透析膜测定牛奶及乳制品中的亚硝酸盐和硝酸盐

样品在热萃取缓冲溶液中,是悬浊液。离心分离并快速冷却分离出脂肪。脱脂后的溶液注射到流动注射分析系统中。系统内透析膜用来除去蛋白质和残余脂肪。通过镉将硝酸根离子还原至亚硝酸根离子。在一个酸性的对氨基苯磺酰胺溶液中,亚硝酸根形成偶氮化合物。它与N-（1-萘基）-乙二胺二盐酸盐（NED）结合形成紫色的含氮染料,在540nm处进行测定。此方法为测定牛奶亚硝酸盐和硝酸盐的常规方法,检出限可达0．02mg／kg,RSD〈10,回收率〉90％。     

Astragalus membranaceus Inhibits Peritoneal Fibrosis via Monocyte Chemoattractant Protein (MCP)-1 and the Transforming Growth Factor-β1 (TGF-β1) Pathway in Rats Submitted to Peritoneal Dialysis

Inflammation and transforming growth factor-β1 (TGF-β1) contribute to the development of peritoneal fibrosis (PF), which is associated with peritoneal dialysis (PD). Astragalus membranaceus (Astragalus) has anti-inflammatory and anti-fibrotic effects in many diseases. The goal of this study was to determine the anti-fibrotic effects of Astragalus on the PF response to PD. A rat model of PD was induced using standard PD fluid, and PF was verified by HE and Masson’s staining, as well as through the expression of fibroblast surface protein (FSP) and collagen III. The expression levels of monocyte chemoattractant protein (MCP)-1, F4/80 (macrophage/monocyte marker in rat), TGF-β1 and the downstream proteins phospho-SMAD 2/3 in dialyzed peritoneal tissue treated with or without Astragalus was evaluated using immunohistochemistry analysis. Overall correlations between MCP-1 and TGF-β1 staining were analyzed using both the Spearman and Pearson methods. The results showed that Astragalus could inhibit the recruitment and activation of monocytes/macrophages, thereby reducing the production of TGF-β1 in the dialyzed peritoneal membrane. PF was also significantly decreased following treatment with Astragalus. MCP-1 expression had a strong positive correlation with TGF-β1 sensitivity, suggesting that the anti-fibrotic function of Astragalus was mediated by MCP-1 and the TGF-β1 pathway. Our results indicate that Astragalus could be a useful agent against PD-induced PF.     

Inorganic ligand-modified, colloid-enhanced ultrafiltration: A novel method for removing uranium from aqueous solution

Inorganic ligand-modified, colloid-enhanced ultrafiltration (ILM-CEUF) is as a novel membrane-based separation method for selectively removing target ions from aqueous solution. Traditional colloid-enhanced ultrafiltration (CEUF) is a well-established membrane-based separation technique that can be used to separate metal ions from other aqueous solution components. Ligand-modified, colloid-enhanced ultrafiltration (LM-CEUF) uses organic ligands that selectively complex target ions and also associate with a water-soluble colloid, such as a surfactant micelle or polyelectrolyte. The colloid, associated -ligand, and target ion are then concentrated using an ultrafilter, producing a filtrate with a low concentration of the target ion. While traditional LM-CEUF techniques are able to provide quantitative separations of a variety of ionic pollutants, the high costs of the chelating agents make such techniques nonviable in most remediation schemes. This study investigated the replacement of organic ligands with carbonate for the selective removal of U(VI) from aqueous solution.In slightly to moderately basic solutions containing carbonate, UO₂(CO₃)₃⁴⁻ can be made to dominate the U(VI) speciation. Using poly(diallyldimethylammonium) chloride, the effectiveness and efficiency of ILM-CEUF for removing U(VI) from other aqueous solution components was investigated as a function of carbonate concentration, pH, and ionic strength. Uranium separations of greater than 99.6% were achieved; even in the presence of large excesses of competing ions. The specific separation of U(VI) from Sr²⁺ was also examined.     

腹膜透析治疗心脏手术后急性肾功能衰竭

目的探讨腹膜透析（PD）对心脏手术后急性肾功能衰竭（ARF）的治疗效果。方法选择心脏手术后ARF患者26例,采用2．5％葡萄糖透析液行PD。观察透析前和透析后24、48、72、96h时尿量、超滤量、电解质、血尿素氮（BUN）、血肌酐（Cr）的变化。结果PD时间3～16d,26例患者中23例患者肾功能恢复至术前水平,1例死于多脏器功能衰竭,2例自动放弃治疗。23例患者经PD治疗后,尿量逐渐增加,BUN、Cr明显低于PD前（P〈0．05）。未发生严重并发症。结论PD安全、经济、有效,是心脏手术后治疗ARF的首要选择。     

渗析法确定土水特征曲线的试验研究

土水特征曲线(SWCC)描述的是土体基质吸力与含水率之间的关系,它对于非饱和土的研究具有重要意义。在测定SWCC的各种方法中,渗析法的试验过程较简单、安全且可靠。本文以合肥地区非饱和膨胀土为研究对象,详细介绍了渗析法获得SWCC的试验过程和技术要领,并采用水浴恒温振荡器代替磁力搅拌器改进了渗析试验。结果表明:采用水浴恒温振荡器进行渗析试验是合理可行的,其优点是一次可以进行相同环境条件下多个浓度的渗析试验;使用水浴恒温振荡器对合肥地区膨胀土进行渗析试验时,其渗析平衡时间约为8天。在此基础上,采用Fredlund-Xing模型的3种型式对渗析试验结果进行了曲线拟合,得到了试验土体的SWCC及其拟合参数,可知模型3种型式的区别主要在高吸力部分。