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Mutations in the Na-K-2Cl co-transporter NKCC2 lead to type I Bartter syndrome, a life-threatening kidney disease. We previously showed that export from the ER constitutes the limiting step in NKCC2 maturation and cell surface expression. Yet, the molecular mechanisms involved in this process remain obscure. Here, we report the identification of chaperone stress 70 protein (STCH) and the stress-inducible heat shock protein 70 (Hsp70), as two novel binding partners of the ER-resident form of NKCC2. STCH knock-down increased total NKCC2 expression whereas Hsp70 knock-down or its inhibition by YM-01 had the opposite effect. Accordingly, overexpressing of STCH and Hsp70 exerted opposite actions on total protein abundance of NKCC2 and its folding mutants. Cycloheximide chase assay showed that in cells over-expressing STCH, NKCC2 stability and maturation are heavily impaired. In contrast to STCH, Hsp70 co-expression increased NKCC2 maturation. Interestingly, treatment by protein degradation inhibitors revealed that in addition to the proteasome, the ER associated degradation (ERAD) of NKCC2 mediated by STCH, involves also the ER-to-lysosome-associated degradation pathway. In summary, our data are consistent with STCH and Hsp70 having differential and antagonistic effects with regard to NKCC2 biogenesis. These findings may have an impact on our understanding and potential treatment of diseases related to aberrant NKCC2 trafficking and expression.  相似文献   
3.
临界通量是膜过程中一种重要的污染特性指标。采用阶梯汲取液浓度递增法测定不同污染物、架桥离子浓度及膜面流速对正渗透(FO)膜过程临界通量的影响。结果表明,海藻酸钠(SA)、腐殖酸(HA)及二氧化硅(SiO2)污染时FO膜临界通量值分别为29.32, 46.35和32.17 L/(m2?h);随Ca2+浓度由0 mmol/L增大至10 mmol/L,SA污染下FO膜的临界通量由29.22 L/(m2?h)显著降低至9.48 L/(m2?h),原因为Ca2+与SA分子中的羧基的螯合作用及Ca2+在膜?污染物之间的架桥作用;此外,当膜面流速从5 cm/s增至15 cm/s时,SA-Ca2+污染下的FO膜临界通量由9.48 L/(m2?h)提高至31.59 L/(m2?h),表明改善膜表面湍动有利于提高临界通量,扩大操作通量范围。  相似文献   
4.
Pervaporation (PV) is a membrane technology that holds great promise for industrial applications. To better understand the PV mechanism, PV dehydrations of various types of organic solvents (methanol, ethanol, iso-propanol, tert-butanol, and acetone) were performed on five types of organosilica and two types of silicon carbide-based membranes, all with different pore sizes. Water permeance was dependent on the types of organic aqueous solutions, which suggested that organic solvents penetrated the pores and hindered the permeation of water. In addition, water permeance of various types of membranes in PV was well correlated with hydrogen permeance in single-gas permeation. Furthermore, a clear correlation was obtained between the permeance ratio in PV and that in single-gas permeation, which was confirmed via the modified-gas translation model. These correlations make it possible to use single-gas permeation properties to predict PV performance.  相似文献   
5.
ABSTRACT

The hydrophobic polyether sulfone membranes were prepared by the sol-gel method to be applied in an air gap membrane distillation setup for desalination. The surface modifications were carried out using Trimethylsilyl chloride (TMSCl) and Methyltrimethoxysilane (MTMS) solutions. The membranes were characterized using Attenuated Total Reflection Infrared (ATR-IR) spectroscopy, Scanning Electron Microscopy (SEM), and Optical Contact Angle (OCA) methods. The effects of membrane preparation as well as operating conditions such as temperature difference, salt concentration, feed rotation speed, and cold-side temperature on membrane performance were investigated using central composite design method. It was found that feed temperature has the largest effect among the parameters on the permeation flux. The flow rate and salt rejection of the membrane in the optimum conditions were 4.47 Kg m?2 h?1 and 99.37%, respectively.  相似文献   
6.
张杰  刘壮  巨晓洁  谢锐  汪伟  褚良银 《化工学报》2021,72(9):4941-4949
二维膜因其可控的结构和通道特有的物理化学性质,在气体分离、海水淡化、污水处理等诸多分离领域展现出巨大的应用潜力。通过层状Mg/Al氢氧化物(LDH)单片与聚乙烯醇(PVA)高分子链之间的氢键相互作用,层层堆叠构建了PVA/LDH复合膜。利用SEM、XRD考察了PVA与LDH的配比对于复合膜层状结构与层间距高度的影响规律。考察了PVA/LDH复合膜的纯水通量及染料模型分子的截留率。结果表明,不同PVA混合量的复合膜断面都具有层状结构。由于氢键作用导致复合膜较之于纯LDH膜的层间距有所缩小,随着PVA含量增加复合膜层间距先减小后增加;在PVA含量为15%时达到最小值,PVA含量超过15%后复合膜层间距有所增加。不同比例复合膜,以PVA质量分数为25%的复合膜的纯水通量最大;同时,该复合膜对分子量在300~800的染料分子具有优异的截留性能,截留率均超过97%。该工作为PVA/LDH复合膜在印染废水处理提供了新思路。  相似文献   
7.
Cellulose microfibers (CMFs) having surfaces modified with polydopamine (PDPA) and octadecylamine (ODA) were prepared, and their reinforcing abilities for polypropylene (PP) were investigated. The PDPA coating was made via self-polymerization of dopamine (P-CMF), and subsequent alkylation was conducted by the reaction with ODA (OP-CMF). The modified CMFs exhibited improved dispersibility in the PP matrix due to the reduced hydrophilicity. The OP-CMF/PP composite prepared by batch mixing had a higher tensile modulus compared to that for the pure PP and composites with unmodified CMFs. However, excess alkylation lowered the tensile modulus, and the presence of an optimal degree of alkylation was demonstrated. The CMF/PP-IM composites fabricated by injection molding exhibited improved tensile properties compared to those prepared by batch mixing. Both the tensile modulus and yield stress were increased by increasing the CMF content and improved by the surface modification of the CMFs.  相似文献   
8.
洪帆  宋洁  杜冰  郑环达  郑来久 《精细化工》2021,38(12):2377-2384
细菌纤维素(BC)是微生物生长过程中产生的以葡萄糖为基本骨架的结构性碳水化合物,具有高纯度、高聚合度、高结晶度、高持水性、高抗张强度和良好的机械强度,在功能材料领域显示了巨大的应用潜力.综述了近年来BC合成菌种筛选的研究现状;分析了BC在透气、吸湿排汗、力学性能和染色与脱色性能调控方面的进展情况;重点总结了BC基材料在抗菌、防紫外线、防辐射、防静电、拒水拒油、导电和传感等功能化改性方面的研究进展;最后,指出BC大规模高效成模和成型技术、差异化高功能BC材料制备技术是未来的重点研发方向.  相似文献   
9.
《Ceramics International》2021,47(21):29908-29918
The cellulose derived carbon/graphene/ZnO aerogel composite was prepared as an electrode in order to investigate the electrochemical properties. Carbon aerogel was synthesized using paper as an available cellulose source, and the composite was obtained through a new and simple preparation method including the immersion of monolithic carbon aerogel in graphene oxide/Zn2+ suspension and subsequent chemical reduction and freeze drying. The morphology, functional groups and crystalline structure of the samples were studied with Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction Spectroscopy (XRD), respectively. Electrochemical performance of the prepared binder free electrodes was examined using Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS). The data revealed that flexible carbon/graphene/ZnO composite resulted in a low density (0.035 g cm−3) electrode with the capacitance of 900 mF cm−2 at a high current density of 10 mA cm−2, lower IR drop and high cyclic stability (capacitance retention of 96%) after 1000 cycles, at 10 mA cm−2. These features were due to the presence of 3D porous conductive network, highly reduced graphene oxide, and the formation of ZnO nanoparticles on graphene sheets. Moreover, polyaniline (PANI) was introduced to carbon/graphene/ZnO composite electrode using electro-oxidation method at different reaction time and aniline concentration in order to achieve remarkably improved capacitance of 2500 mF cm−2 (at 10 mA cm−2) and low charge transfer resistance. Also, after the supercapacitor device assembly, the capacitance was retained. Based on the results, the synthesized composite is a promising material for new generation of lightweight freestanding electrodes with the high electrochemical performance.  相似文献   
10.
An ecofriendly and biodegradable porous structure was prepared from drying aqueous foams based on nano fibrillated cellulose (NFC), extracted from softwood pulp by subcritical water/CO2 treatment (SC-NFC). The primary aim of this work was to use the modified SC-NFC as stabilizer for a water-based Pickering emulsion which upon drying, yielded porous cellulosic materials, a good dye adsorbent. In order to exploit the carboxymethylated SC-NFC (CMSC-NFC, with a degree of substitution of 0.35 and a charge density of 649 μeqv/g) as a stabilizer for water-based Pickering emulsion in subsequent step, an optimized quantity of octyl amine (30 mg/g of SC-NFC) was added to make them partially hydrophobic. A series of dry foam structures were prepared by varying the concentrations of treated CMSC-NFCs and 4 wt% was found to be the optimum concentration to yield foam with high porosity (99%) and low density (0.038 g/cc) along with high compression strength (0.24 MPa), superior to the conventionally extracted NFC. The foams were applied to capture as high as 98% of methylene blue dyes, making them a potential green candidate for treating industrial effluent. In addition, the dye adsorption kinetics and isotherms were found to be well suited with second order kinetics and Langmuir isotherm models.  相似文献   
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