Influences of copolymers (Copovidone,Eudragit RL PO and Kollicoat MAE 30 DP) on stability and bioactivity of spray-dried and freeze-dried lysozyme

Protein stability is the most crucial factor in protein pharmaceutical preparations. Various techniques were applied for producing stable protein formulations such as spray-drying and freeze-drying. However, heating and freezing stresses are disadvantages for proteins using these methods, respectively. Accordingly, excipients have been used to preserve therapeutic effects of proteins during processing and for long period of time. Therefore, influences of Copovidone, Eudragit^® RL-PO and Kollicoat^® MAE-30 DP (as excipients) on stability and integrity of lysozyme (as a model protein) in spray-dried and freeze-dried forms were investigated. Protein formulations in both dried forms were prepared without and with the addition of mentioned excipients at different concentrations. Protein formulations were characterized for yield determination, morphology using scanning electron microscopic (SEM), thermal analysis by Differential Scanning Calorimetry (DSC), secondary structure stability using Fourier transform infrared (FT-IR) spectroscopy and biological activity. All protein formulations were subjected to a stability study as solid protein formulations for 3 weeks at 24?°C/76% relative humidity and aqueous protein samples were stored at 50?°C for 30?min in a water bath. Results showed that Copovidone successfully preserved integrity and biological activity of lysozyme before and after storage in both spray-dried and freeze-dried forms with more advantage for using higher concentration of the same excipient. Smooth spheres of spray-dried lysozyme formulations with Copovidone were smaller than spray-dried lysozyme without and with Kollicoat^® MAE-30 DP, which affected %yield produced. Copovidone has demonstrated valuable protection ability for lysozyme.     

热处理工艺对30MnCrNiMo高强钢组织与性能的影响

借助全自动淬火膨胀仪测定钢的Ac₁、Ac₃相变点,通过对试验钢进行淬火+亚温淬火+回火热处理和淬火+回火热处理,研究了两种热处理工艺下30MnCrNiMo高强钢的组织与性能。结果表明:30MnCrNiMo高强钢的Ac₁、Ac₃相变点分别为653、807 ℃。采用淬火+亚温淬火+回火的热处理工艺所获得的马氏体和铁素体复相组织比直接淬火+回火得到的全马氏体组织更为细小、均匀,试验钢的屈服强度为1499 MPa,伸长率为14.0%,室温、-40 ℃冲击吸收能量分别为35.5和29.5 J,钢的塑性和冲击性能显著提升,有效改善了30MnCrNiMo高强钢的强韧性能。     

淬火工艺及Nb元素对30MnB5钢原奥氏体晶粒度的影响

利用光学显微镜(OM),研究了淬火工艺及Nb元素对30MnB5钢的原奥氏体晶粒度的影响。结果表明:含Nb的30MnB5钢在淬火温度860~920 ℃,保温时间不超过60 min时,原奥氏体晶粒度具有良好的稳定性;当淬火温度达到950 ℃时,保温时间超过30 min后,原奥氏体晶粒尺寸随着保温时间增长逐渐变大;因此,淬火温度低于950 ℃时,Nb元素对30MnB5钢热处理过程中原奥氏体晶粒生长具有抑制作用;当淬火温度达到1000 ℃时,Nb元素仅在30 min以内对原奥氏体晶粒生长有轻微抑制作用,当淬火保温时间超过60 min时,Nb元素完全失去对原奥氏体晶粒生长的抑制作用。     

连轧管机用30Cr3MoV限动芯棒材料的研制

以合金热力学计算和锻件温度场模拟为指导,采用合适的冶炼、锻造、热处理工艺,研制的连轧管机用30Cr3MoV限动芯棒材料的力学性能与H13相当,满足技术要求。     

Piezoelectric sensor based on electrospun PVDF-MWCNT-Cloisite 30B hybrid nanocomposites

Piezoelectric materials have attracted substantial interest in applications such as sensors and actuators. Ferroelectric and piezoelectric polymeric fibers doped with nanoparticles are made for use in nanoscale electronic devices. In this paper, we report on poly (vinylidene fluoride) (PVDF) nanocomposites doped with different ratios of multi-walled carbon nanotube (MWCNT) and Cloisite 30B (OMMT) nanoclay prepared by electrospinning technique. The effect of different ratios of OMMT and MWCNT nanofillers and potential synergistic effect of these fillers on the crystalline structure of PVDF and the performance of resulting piezo-device were studied. Results showed that OMMT increases beta phase crystals and piezoelectric properties of PVDF as compared with MWCNT. Meanwhile, MWCNT decreases impedance and increases dielectric constant of PVDF as compared with OMMT. The acoustic absorption behavior of PVDF/MWCNT/OMMT hybrid nanocomposite was also investigated. It was found that the sound absorption efficiency of PVDF/MWCNT/OMMT hybrid nanocomposites was increased compared with that of pure PVDF fibers and film. No synergistic effect of OMMT and MWCNT on the properties of PVDF was observed.     

Agglomeration and relocation: Manufacturing plant relocation in Korea

This study investigates the magnitude of localization economies by analysing the relocation pattern of Korean establishments in the manufacturing sector. Relocation of establishments is identified by their move across the border of wards, counties, or cities and distinguished between beyond and within their workers' commuting distance. It seems that relocation beyond commuting distance costs more than that within commuting distance since the former includes additional costs related with searching for, hiring, and training new workers. Key findings of this paper show that external benefits from agglomeration are large enough to be recognized by manufacturers through relocation beyond the border of their workers' commuting area. When the own industry's share of employment in all manufacturing industries becomes doubled through relocation, the probability for establishments to relocate over a long distance across the boundary of their workers' commuting area rises by 17 per cent. The results for sub‐samples divided by the age of establishments show that older establishments are more likely to relocate over a long distance to an area with disproportionate presence of establishments in the same industry. These results seem to fit product life cycle theory by Duranton and Puga. As the production process of the product becomes standardized, the firms producing that product tend to relocate to the specialized area where they can reduce the production costs by increasing dependence on the existing intermediate input suppliers, who are more likely to appear in a more specialized area.     

GS30数控车床机电一体化改造研究

阐述了GS30型数控车床存在的问题及改造所要达到的目标,确定了改造的总体技术方案,选择了西门子840D数控系统作为控制装置,并配备了相匹配的各模块型号,做出了机床电气原理图,编制了PLC软件程序,对机床的各参数进行了设定,在完成机械部分和数字伺服系统的调试后,对该机床进行了验收,结果表明:通过改造,提高了机床的可靠性和精度,维修方便,能满足各元件的加工要求,机电一体化改造成本仅为同档次进口机床购价的四分之一。     

MiR-30b Is Involved in the Homocysteine-Induced Apoptosis in Human Coronary Artery Endothelial Cells by Regulating the Expression of Caspase 3

Homocysteine (Hcy) is an independent risk factor for a variety of cardiovascular diseases, such as coronary heart disease, hypertension, stroke, etc. There is a close relationship between the vascular endothelial cell apoptosis and these diseases. Recent studies have shown homocysteine can induce apoptosis in endothelial cells, which may be an important mechanism for the development of theses cardiovascular diseases. Although there are several reports about how the Hcy induces apoptosis in endothelial cells, the exact mechanism is not fully understood. MicroRNAs are small, non-coding RNA. Previous studies have shown that there is a close relationship between several microRNAs and cell apoptosis. However, there are no studies about the role of microRNAs in Hcy-induced apoptosis in endothelial cells so far. In this study, we constructed the model of homocysteine-induced apoptosis in human coronary artery endothelial cells (HCAECs) and found miR-30b was significantly down-regulated by 1 mmol/L Hcy. In addition, overexpression of miR-30b can improve the Hcy-induced apoptosis in HCAECs by downregulating caspase-3 expression. Therefore, miR-30b may play an important role in Hcy-induced apoptosis in endothelial cells.