Protective effects of plasma alpha-tocopherols on the risk of inorganic arsenic-related urothelial carcinoma

Arsenic plays an important role in producing oxidative stress in cultured cells. To investigate the interaction between high oxidative stress and low arsenic methylation capacity on arsenic carcinogenesis, a case-control study was conducted to evaluate the relationship among the indices of oxidative stress, such as urinary 8-hydroxydeoxyquanine (8-OHdG), as well as plasma micronutrients and urinary arsenic profiles on urothelial carcinoma (UC) risk. Urinary 8-OHdG was measured using high-sensitivity enzyme-linked immunosorbent assay kits. The urinary arsenic species were analyzed using high-performance liquid chromatography and hydride generator-atomic absorption spectrometry. Plasma micronutrient levels were analyzed using reversed-phase high-performance liquid chromatography. The present study showed a significant protective effect of plasma alpha-tocopherol on UC risk. Plasma alpha-tocopherol levels were significantly inversely related to urinary total arsenic concentrations and inorganic arsenic percentage (InAs%), and significantly positively related to dimethylarsinic acid percentage (DMA%). There were no correlations between plasma micronutrients and urinary 8-OHdG. Study participants with lower alpha-tocopherol and higher urinary total arsenic, higher InAs%, higher MMA%, and lower DMA% had a higher UC risk than those with higher alpha-tocopherol and lower urinary total arsenic, lower InAs%, lower MMA%, and higher DMA%. These results suggest that plasma alpha-tocopherol might modify the risk of inorganic arsenic-related UC.     

MMA接枝对锂、天然石墨界面的影响

分析了甲基丙烯酸(MMA)接枝到聚丙烯(PP)隔膜表面对金属锂界面稳定性的影响.未处理的PP隔膜,界面电阻随着放置时间的延长而增大,约45d后达到稳定值;接枝MMA后,界面电阻在放置初期很快达到稳定值,约为320 Ω·cm2,稳定一段时间后,增大到新的稳定值380 Ω·cm2.分析了隔膜表面接棱MMA对天然石墨电极界面阻抗行为的影响.     

Synthesis and Characterization of Graft-type MCS Resin

Abstract

MCS resin, formed from methyl methacrylate (MMA), styrene (St), chlorinated polyethylene (CPE), was synthesized by suspension swelling graft-copolymerization. In this paper, the synthesis conditions of MCS, the effect of different synthesis conditions on graft efficiency, the mechanical properties, rheological behavior and morphology were investigated. The graft efficiency increased with increasing CPE content. The apparent viscosity of melt increased with increasing the content of CPE. The copolymer composition was analyzed by FTS-40 Fourier transform infrared spectrometer and PE-2400 element analyzer. The fractured surface morphology of MCS resin was observed by SEM and X-ray energy dispersive spectroscopy.     

伽玛射线辐照接枝对杨树木材力学性能的影响

摘要常温常压下用甲基丙烯酸甲酯（MMA）对速生杨树木材进行浸渍处理,采用^60Coγ射线对其进行辐照接枝改性,考察浸渍时间和吸收剂量对杨树木材主要力学性能的影响,并采用扫描电镜观察接枝前后试材切面的变化。试验结果表明：当浸渍时间为48h,吸收剂量为20kCy时,其顺纹抗压强度、抗弯强度和抗弯弹性模量较素材分别提高了72．3％、72％和42．5％。经过辐照处理后的杨树木材细胞壁被大量聚合物填充,并形成了明显的颗粒状聚合物,其力学性能有较大程度提高。     

Synthesis and characterization of nanosilica ball—PMMA hybrid composites

Organic–inorganic hybrid materials are one of the most attractive topics, which deals from fundamental researches to practical applications. In the present research, we have studied the polymerization of methyl methacrylate (MMA) on the surface of γ‐methacryloxy propyl trimethoxy silane (γ‐MPS) modified nanosilica ball (NSB). The polymeric materials were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and thermo gravimetric analysis (TGA). The results show that new core‐shell structured materials, NSB core‐PMMA shell composites, have been synthesized. The core‐shell hybrid materials can be adjusted to form only a single spherical phase. The addition of the core‐shell hybrid materials to the clearcoat enhances the surface hardness and antiscratch property. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

二茂铁和α-羟基乙基二茂铁对MMA本体聚合的影响

聚甲基丙烯酸甲酯(PMMA)一般由本体聚合或悬浮聚合制得.本体聚合具有生产工艺简单,投资少等优点,但本体聚合周期长,反应热排除困难而易产生自动加速效应导致爆聚,因此制约了本体法制备PMMA.研究微量二茂铁及其衍生物α-羟基乙基二茂铁对MMA本体聚合的影响,结果表明:微量二茂铁或α-羟基乙基二茂铁的加入,聚合时间与聚合温度显著降低,在室温下能实现快速聚合;80℃时,当二茂铁的添加量超过0.17%时,MMA无法爆聚,解决了本体法制备MMA的瓶颈,对工业化生产具有一定的指导意义.     

面向加工变形控制的航空整体结构件拓扑优化设计方法

在毛坯制造过程中,材料力学性能的非均匀性导致铝合金厚板内产生残余应力,以致在后续的高速切削加工过程中,随着材料的大量去除,残余应力的释放使得整体结构件发生变形,严重影响着整体结构件的尺寸稳定性。当初始残余应力水平及状态一定时,随着从毛坯上去除材料切削成形为不同的零件结构,零件变形会表现出不同的形式。因此,研究零件变形与零件结构形式之间的关系对于实现加工过程的高效化和精密化至关重要。首先,通过铝厚板的材料去除等效为残余应力的释放,利用弯曲变形理论建立铝厚板厚度方向上加工变形的解析分析模型及有限元分析模型。通过航空企业现场加工、测试零件后可知：加工变形的解析值、仿真值与测量值相比,无论是幅值水平还是变形曲线,解析值与仿真值完全吻合,而两者与实验值之间仅存在不到10%的幅值误差。其次,为了使得加工变形达到最小,构建以结构体积为约束的拓扑优化设计模型,通过利用一系列凸显式子问题逼近目标和约束函数,构建拓扑优化模型的MMA求解技术。最后利用所提出的优化方法计算出C919直梁件的结构,优化前、后的加工变形分别为22.02 mm与0.7414 mm,在相同的材料去除量情况下,通过优化结构可以使得加工变形减小96.63%。     

皂化对于淀粉-MMA接枝共聚物吸水性能影响的研究

对由玉米淀粉(corn starch,CS)与甲基丙烯酸甲酯(MMA)在KMnO4引发下接枝共聚所制得的CS-MMA接枝共聚物进行皂化,制得了高吸水性树脂.研究了不同条件对其吸水性能的影响,确定了制备该高吸水性树脂的最佳工艺条件.在最佳条件下,树脂的吸水率为900g/g.     

高聚物增强木质基复合材料的结构与性能

为探索性能优异的高聚物增强木质基复合材料的制备方法, 以大青杨木材为研究对象, 选用双功能性单体甲基丙烯酸缩水甘油酯(GMA)和丙烯酸类单体甲基丙烯酸甲酯(MMA), 通过加热引发聚合的方式制得P(GMAcoMMA)/木材复合材料。利用SEM、 FTIR和XRD表征其结构, 并测试其相关性能。结果表明: GMA的加入, 使高聚物与木材细胞壁紧密接触, 界面相互作用力增强; GMA一端的环氧基团, 与木材细胞壁上的羟基充分发生了化学反应, 其双键与MMA单体发生自由基共聚合反应, 从而使P(GMAcoMMA)接枝在木材细胞壁上, 并且主要以无定形态存在。与未改性的木材相比, P(GMAcoMMA)/木材复合材料的静曲强度(MOR)、 尺寸稳定性、 防腐性能和热稳定性依次提高90.53%、 54.05%、 92.85%和31℃。      

JX-300X DCS在MMA装置中的应用

根据连续生产MMA过程的特点,利用浙大中控JX 300X集散控制系统设计了MMA生产过程的控制系统,并将其应用于MMA生产实际装置中.