Improved Controlled Release and Brain Penetration of the Small Molecule S14 Using PLGA Nanoparticles

Phosphodiesterase 7 (PDE7) is an enzyme responsible for the degradation of cyclic adenosine monophosphate (cAMP), an important cellular messenger. PDE7’s role in neurotransmission, expression profile in the brain and the druggability of other phosphodiesterases have motivated the search for potent inhibitors to treat neurodegenerative and inflammatory diseases. Different heterocyclic compounds have been described over the years; among them, phenyl-2-thioxo-(1H)-quinazolin-4-one, called S14, has shown very promising results in different in vitro and in vivo studies. Recently, polymeric nanoparticles have been used as new formulations to target specific organs and produce controlled release of certain drugs. In this work, we describe poly(lactic-co-glycolic acid) (PLGA)-based polymeric nanoparticles loaded with S14. Their preparation, optimization, characterization and in vivo drug release profile are here presented as an effort to improve pharmacokinetic properties of this interesting PDE7 inhibitor.     

智能温度控制仪在铝电解铸造保温炉上的应用

简要介绍了KX-C智能温控仪的性能、特点;结合铝电解铸造保温炉的控制要求,阐述了KX-C智能温控仪对保温炉的恒温控制过程。应用表明,该仪器由于具有控制准确、动作灵敏、接线简单、无需校准、成本较低、可靠性高、无需维护等优点,可很好满足实际生产的要求。     

Mn-Nb-Mo系X70级管线钢奥氏体再结晶规律的研究

研究了Mn-Nb-Mo系XT0级管线钢的再结晶规律，分析了变形温度、变形量等工艺参数对变形奥氏体再结晶百分数的影响，为现场控轧工艺的制定提供了理论依据。     

Facile Fabrication of Povidone Iodine-Embedded Polytetrafluoroethylene Superhydrophobic Films with Improved Antiadhesive and Bactericidal Properties in Bacterial Environments

It remains a challenge to maintain the antiadhesion properties of superhydrophobic films after exposure to bacterial environments. In this work, superhydrophobic bactericidal polymer films via the simple incorporation of polyvinylpyrrolidone-iodine (PVP-I) or iodine into polytetrafluoroethylene (PTFE) are fabricated to improve their antiadhesive and antibacterial capability. Superhydrophobic iodine-embedded films, polytetrafluoroethylene/polyvinylpyrrolidone-iodine and polytetrafluoroethylene-iodine (PTFE/PVP-I and PTFE-I), show excellent antiadhesive and bactericidal performances even post exposure to bacterial solutions as compared to iodine-free counterparts by controlling the release of iodine. Especially, superhydrophobic PTFE/PVP-I films display a more sustained iodine release profile and significant antibacterial properties against gram-positive (S. aureus, methicillin-resistant S. aureus (MRSA)) and gram-negative (E. coli) bacteria. Such a facile combination of antiseptic agents and superhydrophobic surface could be widely used for antiseptic biomedical applications.     

Hypoxia/Temperature/pH Triple Stimuli–Responsive Block Copolymers: Synthesis,Self-Assembly,and Controlled Drug Release

The amphiphilic block copolymer poly(methacrylic acid-co-2-nitroimidazole acrylate)-b-poly(2-(N,N-dimethylamino)ethyl methacrylate) (P(MAA-co-NIMA)-b-PDMAEMA) with the hypoxia/temperature/pH triple responsiveness is synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT), hydrolysis, and 3-(3-dimethylaminopropyl)-1-ethylcarbodiimide (EDC) reactions, and successfully self-assembled into micelles. The hypoxia response in vitro is realized, and then the sensitivity of the self-assembled micelles to the hypoxia condition is studied by controlling the grafting amount of aminated 2-nitroimidazole. Because 2-(N,N-dimethylamino) ethyl methacrylate (DMAEMA) is a typical material sensitive to temperature and pH conditions, the self-assembled micelles are also responsive to temperature and different acidic/basic conditions. In addition, the cumulative release rate of doxorubicin (DOX) at 42 °C, pH = 6.0, and hypoxic conditions increases significantly, and verifies the synergistic promotion effect of the above stimulations. This intelligent polymer with triple response mechanism improves the controllability and efficiency of drug release, and is expected to be a drug carrier for cancer treatment.     

控轧控冷工艺对高强度锚杆钢组织和性能的影响

随着矿井深度的增加,对锚杆支护强韧性的要求越来越高,为了应对这一情况,需要研发出更高强度的锚杆钢。利用锚杆钢研究了轧制工艺、冷却工艺与珠光体、铁素体相比例,析出相析出行为及力学性能的关系。研究结果表明,在中轧后、精轧前采用适当水冷+回复段处理的复合工艺可使晶粒更细小、组织更均匀。对超高强度锚杆钢进行热压缩变形试验,由热模拟试验结果确定相转变温度为A_c1=737 ℃、A_c3=886 ℃。最终筛选出入精轧温度为810 ℃、回复段温度为800 ℃时,可获得的晶粒尺寸达4 μm,珠光体体积分数为66.8%,铁素体体积分数为33.2%,珠光体片层间距达200 nm;另外调整V、Cr、N等析出以提高锚杆钢的强韧性,较低的回复温度有利于细小、弥散、V(C/N)析出相的析出,V(C/N)的析出可进一步改善锚杆钢的力学性能。由该控轧控冷工艺轧制的锚杆钢屈服强度为780 MPa、抗拉强度为930 MPa、硬度为291HV、伸长率为20%。     

SPV490钢轧后在线热处理工艺研究

研究了SPV490钢控轧后在线直接淬火、回火工艺参数与其力学性能之间的关系。分析了不同的工艺参数对钢板组织及性能的影响。结果表明:经奥氏体再结晶区和未再结晶区两阶段结合控制轧制后在线930℃直接淬火、640℃回火,钢板可获得均匀、细小的回火索氏体组织,其综合力学性能均超过标准要求。     

中厚板控制冷却过程的轧件跟踪

控制轧制与控制冷却技术所组成的热机械轧制工艺得到了广泛应用。其中精确的板坯跟踪是保证轧钢过程自动化的前提条件。文中较详细地介绍了热机械轧制过程的板坯跟踪方法。     

Insect sex pheromones

The half-lives (t _1/2) for evaporative loss ofn-alkyl andn-alkenyl acetates from rubber septa were determined at temperatures varying from 15 to 35 °C. The changes int _1/2 with temperature gave high correlations with the equation, Int _1/2 = H/RT+y _o where H is the heat of vaporization,R is the gas constant,T is the absolute temperature, andy _o is a constant. Half-lives changed dramatically with temperature and the degree of change with temperature increased with increasing molecular weight. For mixtures, component ratios changed with temperature, but the degree was modest. At 20 °C there was a 7.5-fold ratio oft _1/2 between members of the homologousn-alkyl orn-alkenyl acetates differing by two carbon atoms. The large change int _1/2 with temperature and with number of carbon atoms is a consequence of the thermodynamic relationships and the temperature range of pheromone usage. Therefore, a similar degree of change inf _1/2 with temperature and number of carbon atoms will apply to other formulations of the same type (those in which the rate of evaporation is first order). The values oft _1/2 at 20 °C mainly agreed very well with those reported previously at room temperature. However, our previously reported values for pentadecyl and hexadecyl acetate were revised. Half-lives were shown to depend on the vapor pressure of a compound in the formulation substrate, but not on the vapor pressure of the pure compound.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

Comparing the revised NIOSH lifting equation to the psychophysical,biomechanical and physiological criteria used in its development

The purpose of this study was to perform a systematic and comprehensive comparison between the recommended weights of lift (RWL) from the revised NIOSH lifting equation, and the specific biomechanical, psychophysical and physiological criteria that were stated to be used in the equation's development. A composite acceptable load (CAL) table was developed for the 216 conditions presented in the female lifting table of Snook and Ciriello (1991). Each CAL value was calculated to correspond to the most conservative load of the three design criteria. The RWLs caused lumbar compression forces close to the biomechanical limit of 3400 N for lifts below knuckle height, but resulted in compression forces that are much lower at higher lifting heights. At moderate lifting frequencies, the average RWL would be acceptable to more than 95% of female workers according to the psychophysical criterion. At the highest frequencies, the RWL was found to be an average of 63% of the CAL values based on the integration of the psychophysical and physiological criteria. It is recommended that ergonomists acknowledge the very conservative nature of the revised NIOSH lifting equation when using it to evaluate occupational lifting tasks.