SDS-PAGE study on photooxidation damage of lysozyme induced by riboflavin

The photooxidation damage of lysozyme under 315-375 nm irradiation in the presence of riboflavin was studied by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).Indica- tions showed that the mechanisms and products of oxidative damage were relative to the concentra- tion of riboflavin,the time of irradiation and the ambience.The type I process was examined in a nitrogen saturated solution,whereas both type I and type II were observed in an aerobic atmosphere and type II was the dominant process.The study also suggested that antioxidants,such as melatonin, can reduce the damage of lysozyme effectively.     

Electrical conductivities of carbon nanotube-filled polycarbonate/polyester blends

Carbon nanotube (CNT)-filled polycarbonate (PC)/poly(butylene terephthalate) (PBT) and polycarbonate (PC)/poly(ethylene terephthalate) (PET) blends containing 1 wt% CNTs over a wide range of blend compositions were prepared by melt mixing in a torque rheometer to investigate the structure-electrical conductivity relationship. Field emission scanning electron microscopy was used to observe the blend morphology and the distribution of CNTs. The latter was compared with the thermodynamic predictions through the calculation of wetting coefficients. It was found that CNTs are selectively localized in the polyester phase and conductive blends can be obtained over the whole composition range (20 wt%, 50 wt% and 80 wt% PBT) for CNT-filled PC/PBT blends, while conductive CNT-filled PC/PET blends can only be obtained when PET is the continuous phase (50 wt%, 80 wt% PET). The dramatic difference in the electrical conductivity between the two types of CNT-filled PC/polyester blends at a low polyester content (20 wt%) was explained by the size difference of the dispersed phases on the basis of the transmission electron microscope micrographs.     

Long lifetime of nanobubbles due to high inner density

As predicted by classical macroscopic theory, the lifetime for nanoscale gas bubbles is extremely short. However, stable gas nanobubbles have been experimentally observed in recent years. In this report, we theoretically show that, if the inner density of gas bubbles is sufficiently high, the lifetime of nanobubbles can increase by at least 4 orders of magnitude, and even approaches the timescale for experimental observations. Supported by the National Natural Science Foundation of China (Grant Nos. 10474109 and 10674146)     

St/交联剂乳液共聚包覆硬脂酸改性碳酸钙颗粒的研究

在硬脂酸改性的纳米碳酸钙存在下,通过苯乙烯(St)与多乙烯基单体的乳液共聚合,制备了以纳米碳酸钙为核,以交联聚苯乙烯(PS)为壳的交联型PS/碳酸钙复合纳米粒子.研究了多乙烯基单体的种类和用量以及碳酸钙的用量对聚合反应以及包覆的影响.结果表明,多乙烯基单体以及碳酸钙的引入会使聚合反应速率有不同程度的降低;使用1%~5%的TMPTMA或DVB,可实现PS对碳酸钙颗粒的牢固包覆,不可抽提的PS达94%以上;当碳酸钙用量改变时,需要适当调整乳化剂和多乙烯基单体的用量;IR和TGA的结果表明,随着碳酸钙用量增加,产物中的碳酸钙含量也相应增加;TEM照片和计算结果显示,当碳酸钙用量为14.8%时,绝大部分碳酸钙颗粒被包覆,且基本上每个乳胶粒中包覆一个碳酸钙颗粒,复合粒子具有清晰的核壳结构,壳层厚度约为10 nm,而当碳酸钙用量增加到29.3%和58.7%时,壳层厚度减小,并且出现较多裸露的碳酸钙颗粒.     

Co doping effects on structural, electronic and magnetic properties in Mn2VGa

The electronic structure and magnetic properties of Co-doped Heusler alloys (Mn_1−xCo_x)₂ VGa (x=0.0, 0.25, 0.5, 0.75, 1.0) have been studied by first-principles calculations. The results show that the lattice constants decrease with increasing Co content except x=1.0. The spin polarization for x=0.5 is only 34%, much lower than the other concentrations. The compounds of x=0.0, 0.25 show nearly half-metallicity because the Fermi level slightly touches the valence bands. And the compounds of x=0.75, 1.0 exhibit the half-metallic character with 100% spin polarization. It is found the local moments of Mn(Co) basically show a linear increasing trend while the moments of V show a linear decreasing trend with increasing doping concentration. However, the local moments for x=0.5 quite depart from the linear trend. The majority-spin component at the Fermi level increases while the minority-spin component at the Fermi level decreases with the substitution of Co atoms for Mn atoms when x≤0.75. For x≥0.75, the majority-spin component remains more or less the same and the gap in the minority DOS increases with Co doping. The majority spin states are shifted to valence bands and the majority spin states around E_F increase due to a leakage of charge from the unoccupied spin-up states to the occupied majority states with increasing Co content.