常压低温冷等离子体还原Fe2O3的研究

目的研究常压低温冷等离子体还原过程中气体常量对Fe_2O_3还原过程的影响。方法采用冷压成形后高温烧结的方式制备Fe_2O_3试样块,利用射流型常压冷等离子体还原铁基氧化物,通过X射线衍射仪分析还原前后的物相,用扫描电镜观察还原前后的微观形貌,讨论了还原过程中气氛的作用和影响。结果等离子体的还原能力取决于还原气体的成分与含量,其中氮等离子体在常温常压条件下无法还原Fe_2O_3,氨气+氮气混合气体为工作气体的常压低温冷等离子体能将Fe_2O_3还原成Fe_3O_4和金属Fe,还原能力随着氨气含量的增加而增强,还原速率随着氨气含量的增加而下降。氨气在等离子体中可产生多种还原性物质,如N_2H_4、H和H_2*等,能将Fe_2O_3还原,且过程表现为过渡还原,即Fe_2O_3先被还原成Fe_3O_4,再被还原成金属Fe。结论常压低温冷等离子体中的电子与热效应无法还原Fe_2O_3,添加氨气后的等离子体中产生了一系列的活性物质,才能还原金属Fe表面的氧化物。     

中国古代几种含氮物质的热处理渗入效果初探

根据文献记载，我国古代有采用含氮物质进行热处理事实，分析了古代渗氮处理的可能性和前提条件，具体实践了几种文献记载含氮物质的渗氮处理。试验结果表明，Lu硝容易升华，基本没有渗氮效果，但可能起到一定催渗作用；硝单独使用渗氮效果也不明显；牛角灰、毛发灰、箬皮灰都有明显的渗氮作用；加硝有促进作用，硝与毛发灰共同作用有显著渗氮效果，并获得了较好的含氮化合物渗层。     

新轴承寿命理论在应用中的探讨

本文介绍了基于滚动轴承弹性流体动力润滑研究的成果 ,进而建立的新标准 ISO2 81 / I轴承的寿命理论 ,着重分析了新轴承寿命理论下影响轴承寿命的各种因素 ,作为实际应用中延长轴承使用寿命的理论根据     

石蜡聚苯乙烯微球的制备Ⅱ.分散剂及复合介质的影响

通过悬浮聚合法合成了石蜡聚苯乙烯微球,研究了合成过程中复合介质的配比和用量以及分散剂种类和用量对微球粒径及其分布的影响。结果表明:采用聚乙烯醇作分散剂,更有利于合成小粒径高产率的石蜡聚苯乙烯微球,悬浮聚合体系中水-乙醇复合介质的最佳体积配比和用量分别为1:2.5和150mL。     

四氯化碳过程助剂及其替代技术的应用与发展现状

简要介绍了破坏臭氧物质的主要品种、用途和国家淘汰计划,着重介绍了四氯化碳在过程助剂领域中的主要用途、用量以及替代技术的开发现状和趋势,指出了研究四氯化碳转化技术的紧迫性、重要性和选择转化反应需要考虑的因素。     

煤化工废水中酚类物质、氨氮的处理方法研究进展

煤化工废水是一种典型的有毒、难降解性工业废水。经预处理后的废水中仍含有大量的有毒有害物质,其中氨氮、酚类物质是典型的代表,氨氮含量在200mg/L左右,酚类物质含量占COD值的40%以上,浓度高达1000mg/L。如果对这些高毒性的物质不加处理或处理深度不够,则对环境和生命都会造成极大的危害。因此,酚类物质、氨氮的有效处理是实现煤化工废水无害化处理以及绿色可持续发展的关键。本综述主要从酚类物质处理技术与工艺、氨氮处理技术与工艺两个方面梳理了国内外煤化工废水中酚类物质、氨氮的处理现状,也全面分析了各种技术与工艺的优缺点。使该领域的研究人员以更加科学的方法了解煤化工废水中酚类物质、氨氮处理技术与工艺的研究现状和发展趋势。最后,探讨了未来煤化工废水中酚类物质、氨氮处理的发展前景。     

Real-Time Monitoring the Effect of Cytopathic Hypoxia on Retinal Pigment Epithelial Barrier Functionality Using Electric Cell-Substrate Impedance Sensing (ECIS) Biosensor Technology

Disruption of retinal pigment epithelial (RPE barrier integrity is a hallmark feature of various retinal blinding diseases, including diabetic macular edema and age-related macular degeneration, but the underlying causes and pathophysiology are not completely well-defined. One of the most conserved phenomena in biology is the progressive decline in mitochondrial function with aging leading to cytopathic hypoxia, where cells are unable to use oxygen for energy production. Therefore, this study aimed to thoroughly investigate the role of cytopathic hypoxia in compromising the barrier functionality of RPE cells. We used Electric Cell-Substrate Impedance Sensing (ECIS) system to monitor precisely in real time the barrier integrity of RPE cell line (ARPE-19) after treatment with various concentrations of cytopathic hypoxia-inducing agent, Cobalt(II) chloride (CoCl₂). We further investigated how the resistance across ARPE-19 cells changes across three separate parameters: R_b (the electrical resistance between ARPE-19 cells), α (the resistance between the ARPE-19 and its substrate), and C_m (the capacitance of the ARPE-19 cell membrane). The viability of the ARPE-19 cells and mitochondrial bioenergetics were quantified with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and seahorse technology, respectively. ECIS measurement showed that CoCl₂ reduced the total impedance of ARPE-19 cells in a dose dependent manner across all tested frequencies. Specifically, the ECIS program’s modelling demonstrated that CoCl₂ affected R_b as it begins to drastically decrease earlier than α or C_m, although ARPE-19 cells’ viability was not compromised. Using seahorse technology, all three concentrations of CoCl₂ significantly impaired basal, maximal, and ATP-linked respirations of ARPE-19 cells but did not affect proton leak and non-mitochondrial bioenergetic. Concordantly, the expression of a major paracellular tight junction protein (ZO-1) was reduced significantly with CoCl_2-treatment in a dose-dependent manner. Our data demonstrate that the ARPE-19 cells have distinct dielectric properties in response to cytopathic hypoxia in which disruption of barrier integrity between ARPE-19 cells precedes any changes in cells’ viability, cell-substrate contacts, and cell membrane permeability. Such differences can be used in screening of selective agents that improve the assembly of RPE tight junction without compromising other RPE barrier parameters.     

7,8-Dihydroxiflavone Protects Adult Rat Axotomized Retinal Ganglion Cells through MAPK/ERK and PI3K/AKT Activation

We analyze the 7,8-dihydroxyflavone (DHF)/TrkB signaling activation of two main intracellular pathways, mitogen-activated protein kinase (MAPK)/ERK and phosphatidylinositol 3 kinase (PI3K)/AKT, in the neuroprotection of axotomized retinal ganglion cells (RGCs). Methods: Adult albino Sprague-Dawley rats received left intraorbital optic nerve transection (IONT) and were divided in two groups. One group received daily intraperitoneal DHF (5 mg/kg) and another vehicle (1%DMSO in 0.9%NaCl) from one day before IONT until processing. Additional intact rats were employed as control (n = 4). At 1, 3 or 7 days (d) after IONT, phosphorylated (p)AKT, p-MAPK, and non-phosphorylated AKT and MAPK expression levels were analyzed in the retina by Western blotting (n = 4/group). Radial sections were also immunodetected for the above-mentioned proteins, and for Brn3a and vimentin to identify RGCs and Müller cells (MCs), respectively (n = 3/group). Results: IONT induced increased levels of p-MAPK and MAPK at 3d in DHF- or vehicle-treated retinas and at 7d in DHF-treated retinas. IONT induced a fast decrease in AKT in retinas treated with DHF or vehicle, with higher levels of phosphorylation in DHF-treated retinas at 7d. In intact retinas and vehicle-treated groups, no p-MAPK or MAPK expression in RGCs was observed. In DHF- treated retinas p-MAPK and MAPK were expressed in the ganglion cell layer and in the RGC nuclei 3 and 7d after IONT. AKT was observed in intact and axotomized RGCs, but the signal intensity of p-AKT was stronger in DHF-treated retinas. Finally, MCs expressed higher quantities of both MAPK and AKT at 3d in both DHF- and vehicle-treated retinas, and at 7d the phosphorylation of p-MAPK was higher in DHF-treated groups. Conclusions: Phosphorylation and increased levels of AKT and MAPK through MCs and RGCs in retinas after DHF-treatment may be responsible for the increased and long-lasting RGC protection afforded by DHF after IONT.     

Poly(chitosan-ester-ether-urethane) Hydrogels as Highly Controlled Genistein Release Systems

Polymeric hydrogels play an increasingly important role in medicine, pharmacy and cosmetology. They appear to be one of the most promising groups of biomaterials due to their favorable physicochemical properties and biocompatibility. The objective of the presented study was to synthesize new poly(chitosan-ester-ether-urethane) hydrogels and to study the kinetic release of genistein (GEN) from these biomaterials. In view of the above, six non-toxic hydrogels were synthesized via the Ring-Opening Polymerization (ROP) and polyaddition processes. The poly(ester-ether) components of the hydrogels have been produced in the presence of the enzyme as a biocatalyst. In some cases, the in vitro release rate of GEN from the obtained hydrogels was characterized by near-zero-order kinetics, without “burst release” and with non-Fickian transport. It is important to note that developed hydrogels have been shown to possess the desired safety profile due to lack of cytotoxicity to skin cells (keratinocytes and fibroblasts). Taking into account the non-toxicity of hydrogels and the relatively highly controlled release profile of GEN, these results may provide fresh insight into polymeric hydrogels as an effective dermatological and/or cosmetological tool.     

海绵城市入渗设施淤堵研究进展及长期性能改进方案探讨

针对海绵城市渗井、渗透管和渗透塘等典型入渗设施,阐述了淤堵机理和性能改进研究的意义。将淤堵影响因素分为淤堵物源性质、水动力条件和滤层特性3个方面,分别围绕这3个方面概述了淤堵研究进展。将我国海绵城市入渗设施淤堵问题研究的不足和需要加强研究的方面归纳为:淤堵物源特征仍然不够明确,水流条件研究不够全面,间歇运行的影响研究不够,实际组合滤层结构缺乏研究,时间效应研究不够,主要作用机制认识存在分歧,结构形式和运行维护方案研究不够,缺乏原型试验和实际工程研究。针对我国海绵城市建设,提出急需针对典型城市区域监测实际雨洪,尤其是久未下雨后暴雨中的第1波雨洪,研究入渗设施的淤堵物源性质。基于类似问题的研究工作,分析了入渗设施滤层性能改进的途径,认为可更换滤层方案可以突破入渗设施淤堵问题,促进入渗设施的更广泛运用,从而保障海绵城市建设的长期效果。