Colmation and Depth Filtration within Streambeds: Retention of Particles in Hyporheic Interstices

Colmation refers to the retention processes that can lead to the clogging of the top layer of channel sediments and decolmation refers to the resuspension of deposited fine particles. Internal colmation, clogging of the interstices directly below the armor layer, may form a thin seal that disconnects surface water from hyporheic water by inhibiting exchange processes. The settling of particles under low flow conditions can cause external colmation. Colmated channel sediments are characterized by reduced porosity and hydraulic conductivity as well as by a consolidated texture. The term ‘depth filtration’ refers to the transport and storage of fine matrix sediments in interstitial layers. Depth filtration is of significance for the transport of colloidal and fine particulate inorganic as well as organic matter within the hyporheic interstices and into the alluvial aquifer. The role of depth filtration is assessed for the content (given in mg per liter) of matrix fine particles retained in the coarse framework sediment of a gravel-bed river in Switzerland. Sediment samples were taken by freeze-coring with liquid nitrogen down to 70 cm depth and by piezometers down to 150 cm depth. Seventy-two percent of the mobile matrix fine particles were smaller than 0.1 mm and 50% were smaller than 0.03 mm. The content of fines tended to increase with depth, although higher accumulations were found at intermediate depths in sediments influenced by exfiltrating ground water. Interstitial detrital particles >90 μm showed vertical distribution patterns opposing those of total particles. These relationships revealed a differential significance of import, storage, and transport within three types of hydrological exchange zones (infiltration, horizontal advection, exfiltration) in the cross-section of the stream.     

猪O型口蹄疫病毒细菌样颗粒疫苗的制备与免疫原性鉴定

验证基于革兰氏阳性增强基质(Gram-positive enhancer matrix,GEM)展示口蹄疫病毒细菌样颗粒(Bacteria-like particles,BLP)疫苗的可行性。按照大肠杆菌偏好性密码子优化合成基于猪口蹄疫病毒Mya98株序列的3种抗原基因设计,并将其插入到含有锚钩蛋白基因的原核表达载体p QZ-PA,鉴定阳性后转入Escherichia coli BL21,进行诱导表达。利用SDS-PAGE与Western blotting对目的基因表达及产物的可溶性进行分析。利用GEM颗粒纯化目的蛋白,制备细菌样颗粒疫苗抗原;利用BCA试剂盒测定重组蛋白的浓度,将重组蛋白与白油佐剂乳化,制备疫苗,免疫5周龄小鼠,同时设商品化多肽苗对照与空白对照,免疫后不同时间采集试验小鼠血清,利用口蹄疫病毒多肽ELISA抗体检测试剂盒和O型口蹄疫抗体液相阻断酶联免疫(Enzyme-linked immunosorbent assay,ELISA)检测试剂盒检测免疫小鼠血清的抗体水平;利用噻唑蓝比色法(Methylthiazolyldiphenyl-tetrazolium bromide,MTT)测定淋巴细胞增殖情况;利用荧光定量PCR方法检测相关细胞因子表达,评价细胞免疫水平。SDS-PAGE结果表明,设计在大肠杆菌中的3种口蹄疫病毒抗原基因均以可溶形式获得高效表达;Western blotting结果显示,表达的重组蛋白能够与口蹄疫病毒阳性血清发生反应,利用GEM颗粒能够实现重组蛋白的一步离心纯化,制备BLP疫苗抗原;免疫试验结果表明,设计的重组抗原B(T1BT2)4B不但能够刺激免疫小鼠产生更高水平的多肽特异性ELISA抗体与口蹄疫特异性液相阻断抗体,而且产生了更高水平的脾淋巴细胞增殖及Th1型的细胞因子分泌。初步实验结果表明,本研究制备的BLP疫苗GEM-B(T1BT2)4B具有良好的免疫原性,为研究口蹄疫病毒基因工程亚单位疫苗开辟了一条新的思路。     

戊型肝炎病毒样颗粒在重组汉逊酵母中的发酵表达、纯化及其免疫原性分析

为了研制戊型肝炎新型基因工程疫苗,利用汉逊酵母表达系统表达重组戊型肝炎病毒样颗粒,成功构建了重组戊型肝炎疫苗工程菌株HP/HEV2.3,对该菌株的发酵条件和纯化工艺进行了研究。先将工作种子批进行发酵培养,收集发酵后的细胞培养物;对其先后进行细胞破碎、澄清和超滤、硅胶吸附和解吸附、超滤浓缩换液、色谱纯化及除菌过滤,制得重组汉逊酵母戊型肝炎病毒样颗粒,纯化收率为33%,纯度达99%;电镜观察显示该重组汉逊酵母戊型肝炎病毒样颗粒与天然戊型肝炎病毒颗粒理论大小一致,为32 nm;基因序列与理论一致;SDS-PAGE分析结果表明其表达的外源蛋白质分子量与预期的目的蛋白质分子量大小一致,均为56 k Da,表达量占细胞总蛋白的26%,表达水平为1.0 g/L发酵液;Western blotting、ELISA活性检测及小鼠免疫接种效力试验ED_(50)结果表明,此重组汉逊酵母戊型肝炎病毒样颗粒具有良好的抗原性和免疫原性,可用于制造戊型肝炎新型基因工程疫苗。     

前列地尔联合益肾化湿颗粒对糖尿病肾病患者血糖、血脂、肾功能以及尿足细胞相关蛋白的影响

目的:分析前列地尔联合益肾化湿颗粒对糖尿病肾病患者血糖、血脂、肾功能以及尿足细胞相关蛋白的影响。方法:98例糖尿病肾病患者按抽签法分为对照组与实验组,各49例,对照组予以前列地尔治疗,实验组基于对照组加用益肾化湿颗粒治疗,比较两组疗效,糖化血红蛋白(Hb A1c)、血糖(FPG)、餐后2 h血糖低(2h PG),甘油三脂(TG)、总胆固醇(TC)、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C),血尿素氮(BUN)、肌酐(Cr)、β2微球蛋白(β2-MG)、胱抑素(Cys-C),尿足细胞标志蛋白(PCX)nephrin,安全性。结果:实验组总有效率高于对照组(P0.05)。治疗后,两组Hb Alc、FPG、2h PG比较无差异(P0.05)。实验组TG、TC、LDL-C、BUN、Cr、β2-MG、Cys-c、PCX、尿nephrin/尿Cr低于对照组(P0.05)。实验组HDL-C高于对照组(P0.05)。结论:前列地尔联合益肾化湿颗粒治疗对糖尿病肾病的疗效确切,可利于血糖、血脂、肾功能的改善,降低尿足细胞相关蛋白的浓度。     

Ultrafine Metal Nanoparticles/N‐Doped Porous Carbon Hybrids Coated on Carbon Fibers as Flexible and Binder‐Free Water Splitting Catalysts

By employing in situ reduction of metal precursor and metal‐assisted carbon etching process, this study achieves a series of ultrafine transition metal‐based nanoparticles (Ni–Fe, Ni–Mo) embedded in N‐doped carbon, which are found efficient catalysts for electrolytic water splitting. The as‐prepared hybrid materials demonstrate outstanding catalytic activities as non‐noble metal electrodes rendered by the synergistic effect of bimetal elements and N‐dopants, the improved electrical conductivity, and hydrophilism. Ni/Mo₂C@N‐doped porous carbon (NiMo‐polyvinylpyrrolidone (PVP)) and NiFe@N‐doped carbon (NiFe‐PVP) produce low overpotentials of 130 and 297 mV at a current density of 10 mA cm^?2 as catalysts for hydrogen evolution reaction and oxygen evolution reaction, respectively. In addition, these binder‐free electrodes show long‐term stability. Overall water splitting is also demonstrated based on the couple of NiMo‐PVP||NiFe‐PVP catalyzer. This represents a simple and effective synthesis method toward a new type of nanometal–carbon hybrid electrodes.     

二甲双胍片联合糖脉康颗粒对2型糖尿病患者血清IL-6、TNF-?琢、CRP、APN水平的影响

摘要 目的：研究二甲双胍片联合糖脉康颗粒对2型糖尿病患者血清白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)、脂联素(APN)水平的影响。方法：选择2013年2月至2016年10月在我院接受治疗的2型糖尿病患者130例,按照给药方法不同分为对照组和观察组,对照组采用二甲双胍片治疗,观察组以对照组为基础联合糖脉康治疗。治疗8周后,对比两组患者治疗前后血清IL-6、TNF-α、CRP、APN、总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C),空腹血糖(FBC)、餐后2小时血糖(2hPBG)、糖化血红蛋白(HbAlc)、胰岛抵抗指数( HOMA-IR)、胰岛β细胞分泌功能指数(HOMA-IS)和胰岛素敏感指数(ISI)的变化。结果：治疗后,两组患者血清IL-6、TNF-α、CRP、TC、TG、LDL-C,FBC、2hPBC、HbAlc,HOMA-IR均较治疗前均明显降低,而血清APN、HDL-C、HOMA-IS、ISI均明显增高(P<0.05);与对照组相比,观察组患者血清IL-6、TNF-α、CRP、TC、TG、LDL-C,FBC、2hPBC、HbAlc、HOMA-IR水平均较低(P<0.05),血清APN、HDL-C,HOMA-IS、ISI水平较高(P<0.05)。结论：二甲双胍片联合糖脉康治疗2型糖尿病患者可有效稳定其血脂血糖,改善胰岛功能,可能与其降低血清IL-6、TNF-α、CRP水平,增加血清APN水平有关。     

High yield process for the production of active human α‐galactosidase a in CHO‐K1 cells through lentivirus transgenesis

Fabry disease is an X‐linked recessive disorder caused by a deficiency in lysosomal α‐Galactosidase A. Currently, two enzyme replacement therapies (ERT) are available. However, access to orphan drugs continues to be limited by their high price. Selection of adequate high‐expression systems still constitutes a challenge for alleviating the cost of treatments. Several strategies have been implemented, with varying success, trying to optimize the production process of recombinant human α‐Galactosidase A (rhαGAL) in Chinese hamster ovary (CHO‐K1) cells. Herein, we describe for the first time the application of a strategy based on third‐generation lentiviral particles (LP) transduction of suspension CHO‐K1 cells to obtain high‐producing rhαGAL clones (3.5 to 59.4 pg cell^?1 d^?1). After two purification steps, the active enzyme was recovered (2.4 × 10⁶ U mg^?1) with 98% purity and 60% overall yield. Michaelis‐Menten analysis demonstrated that rhαGAL was capable of hydrolyzing the synthetic substrate 4MU‐α‐Gal at a comparable rate to Fabrazyme®, the current CHO‐derived ERT available for Fabry disease. In addition, rhαGAL presented the same mannose‐6‐phosphate (M6P) content, about 40% higher acid sialic amount and 33% reduced content of the immunogenic type of sialic acid (Neu5Gc) than the corresponding ones for Fabrazyme®. In comparison with other rhαGAL production processes reported to date, our approach achieves the highest rhαGAL productivity preserving adequate activity and glycosylation pattern. Even more, considering the improved glycosylation characteristics of rhαGAL, which might provide advantages regarding pharmacokinetics, our enzyme could be postulated as a promising alternative for therapeutic use in Fabry disease. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1334–1345, 2017