IgG and IgA with Potential Microbial-Binding Activity Are Expressed by Normal Human Skin Epidermal Cells

The innate immune system of the skin is thought to depend largely on a multi-layered mechanical barrier supplemented by epidermis-derived antimicrobial peptides. To date, there are no reports of antimicrobial antibody secretion by the epidermis. In this study, we report the expression of functional immunoglobulin G (IgG) and immunoglobulin A (IgA), previously thought to be only produced by B cells, in normal human epidermal cells and the human keratinocyte line HaCaT. While B cells express a fully diverse Ig, epidermal cell-expressed IgG or IgA showed one or two conservative V_HDJ_H rearrangements in each individual. These unique VDJ rearrangements in epidermal cells were found neither in the B cell-derived Ig VDJ databases published by others nor in our positive controls. IgG and IgA from epidermal cells of the same individual had different VDJ rearrangement patterns. IgG was found primarily in prickle cells, and IgA was mainly detected in basal cells. Both epidermal cell-derived IgG and IgA showed potential antibody activity by binding pathogens like Staphylococcus aureus, the most common pathogenic skin bacteria, but the microbial-binding profile was different. Our data indicates that normal human epidermal cells spontaneously express IgG and IgA, and we speculate that these Igs participate in skin innate immunity.     

绿色多酸苏氨酸复合材料的合成及对大肠杆菌抗菌性能研究

合成Keggin结构H7Ni(H2O)FeW11O39.14H2O和H6Ti(H2O)CrW11O39.14H2O杂多酸,并与苏氨酸复合采用离子交换法制得两种复合材料,采用IR对产物进行了表征,测试了材料对大肠杆菌的抗菌性能。     

B2O3-K2O-Sb2O3系统玻璃的光学折射率及带隙

高折射率和非线性光学玻璃可以用于高速光开关、光学存储器、新型光纤和光学运算元件等,其研究受到各国科技工作者的高度重视,本文采用熔融淬冷法制备了组成为(85-x)B₂O₃-15K₂O-xSb₂O₃(x=70, 75, 80, 85)的4组玻璃,测试了玻璃样品的密度、折射率、热学性能、拉曼光谱和吸收光谱,利用玻璃样品的吸收光谱计算了其直接允许光学带隙、间接允许光学带隙及Urbach能量。结果表明：随着Sb₂O₃含量的增加,玻璃样品的密度从4.445g/cm³逐渐增加到4.767g/cm³,折射率从1.9438增加到2.0058,玻璃转变温度从291℃降低到260℃,玻璃析晶温度从463℃降低到370℃,直接光学带隙从3.2775eV降低到3.1379eV,间接光学带隙从3.1444eV降低到3.0256eV,Urbach能量从0.137eV逐渐减小到0.107eV。说明Sb₂O₃-K₂O-B₂O₃系统玻璃可以作为新型的非线性光学玻璃候选材料之一。     

氧化石墨烯杂化分子印迹复合膜制备及性能研究

采用改进的Hummers法,通过冷冻干燥制备了氧化石墨烯(GO)。以辛弗林盐酸盐为模板分子,水溶性的丙烯酰胺为功能单体,离子液体(溴代1-丁基-3-甲基咪唑)为致孔剂,把GO加入聚合液中,制备了GO杂化的分子印迹复合膜(GO-MIM)。利用透射电镜、扫描电镜、X射线衍射和红外光谱等方法对GO及GO-MIM进行了表征。通过将分子印迹膜技术与GO相结合,明显提高了分子印迹膜的力学性能。吸附及渗透实验表明,GO-MIM可在纯水溶剂体系,对辛弗林盐酸盐具有很好的选择性吸附能力和优先透过能力,体现了明显的分子印迹效果。     

Synthesis of micro-sized SnO2@carbon hollow spheres with enhanced lithium storage properties

Uniform and stable micro-sized SnO(2) hollow spheres are prepared by templating against polystyrene microspheres. After being coated with a thin layer of amorphous carbon, the as-obtained SnO(2)@carbon hollow microspheres are shown to exhibit improved lithium storage properties, delivering a reversible capacity of 570 mA h g(-1) after 50 cycles at a high current density of 400 mA g(-1).     

射频磁控溅射技术制备羟基磷灰石生物涂层及其微结构

采用射频磁控溅射技术在Ti6Al4V基体上成功制备了羟基磷灰石(hydroxyapatite。HA)涂层,利用扫描电镜、X射线衍射、Fourie,红外光谱和电子探针线扫描对HA涂层的形貌、相组成和化学组成进行分析。结果表明：磁控溅射制备的涂层为非晶态且存在羟基的缺失,其Ca与P的摩尔比n(Ca)／n(P)为1．69．经大气条件下,后处理可恢复羟基并显着提高涂层的晶化程度。涂层与基体结合紧密,呈现有利于骨性结合的内部致密、表面多孔的梯度结构。     

Fabrication of ZrB2-SiC ceramic composites by optimized gel-casting method

The ZrB₂-SiC ceramics with homogenous microstructures were successfully fabricated by the optimized gel-casting method and pressureless sintering. The effects of the processing parameters, including the monomer content, cross-linker/monomer ratios, initiator addition, catalyst concentration and polymerization temperature, on the final gel properties were systematically investigated. The rheological behavior and stability of ZrB₂-SiC suspensions were evaluated, and the microstructures and mechanical properties of sintered ceramics were also analyzed. The homogenous gel networks containing low monomer content (4 wt%) and without catalysts had been successfully obtained, which could be mainly attributed to the homogeneous distribution of crosslinking points and temperature-induced gelation. The crack-free and complex-shaped ZrB₂-SiC ceramic composites were achieved by the optimized gel-casting, which could reach the highest relative density of 97.2% and the flexural strength of 402 ± 57 MPa, respectively. This study provides an optimized gel-casting process for fabricating ZrB₂-SiC ceramics with excellent properties by low colloidal additives and without catalysts.     

长短棱长度比对4WS转子密炼机混合特性的影响

4WS转子是一种新型的密炼机转子,其中长短棱长度比是重要的几何结构设计参数。利用POLYFLOW软件,分别对长短棱长度比为2∶1、3∶1、4∶1的4WS型转子密炼机流场进行了有限元模拟。通过粒子示踪技术,对三种密炼机的宏观混合形态进行了粒子可视化追踪。利用流场数据,计算了典型的分散混合和分布混合评价参数,对三种不同转子密炼机内流体的混合效率进行了对比分析,探究长短棱长度比对4WS转子密炼机混合特性的影响规律。结果表明,相对于长短棱长度比为3∶1和2∶1的4WS型转子密炼机,长短棱长度比为4∶1的4WS型转子密炼机分散和分布混合能力均有了较大的提升。     

MgO膨胀剂对超高性能混凝土收缩性能的影响

为明确MgO膨胀剂(MEA)对超高性能混凝土(UHPC)收缩性能及抗压强度的影响,本文通过抗压强度和自收缩试验来评估不同活性、不同掺量MEA对UHPC的作用效果,并对其作用机理进行分析。结果表明,不同活性的MEA均能有效抑制UHPC的收缩,其中高活性的MEA水化速率相对较大,对UHPC早期的自收缩抑制效果明显。然而,MEA与水泥之间“争水效应”的存在,使得掺加高活性MEA的UHPC的抗压强度较同龄期掺加低活性MEA的UHPC的抗压强度低6%左右。MEA的掺量是影响其减缩效果的重要因素,当MEA掺量超过6%(质量分数)时,受UHPC基体自由水含量的限制导致其膨胀性能不能充分激发,难以进一步提升MEA的膨胀性能。综合考虑MEA对UHPC的收缩性能与力学性能的影响,本文建议选用活性值为220 s、掺量为6%的低活性MEA。     

Thermodynamic analysis of reaction pathways and equilibrium yields for catalytic pyrolysis of naphtha

The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha. Herein, for a better catalyst design and operation parameters optimization, the reaction pathways and equilibrium yields for the catalytic pyrolysis of C_5–8 n/iso/cyclo-paraffins were analyzed thermodynamically. The results revealed that the thermodynamically favorable reaction pathways for n/iso-paraffins and cyclo-paraffins were the protolytic and hydrogen transfer cracking pathways, respectively. However, the formation of light paraffin severely limits the maximum selectivity toward light olefins. The dehydrogenation cracking pathway of n/iso-paraffins and the protolytic cracking pathway of cyclo-paraffins demonstrated significantly improved selectivity for light olefins. The results are thus useful as a direction for future catalyst improvements, facilitating superior reaction pathways to enhance light olefins. In addition, the equilibrium yield of light olefins increased with increasing the chain length, and the introduction of cyclo-paraffin inhibits the formation of light olefins. High temperatures and low pressures favor the formation of ethylene, and moderate temperatures and low pressures favor the formation of propylene. n-Hexane and cyclohexane mixtures gave maximum ethylene and propylene yield of approximately 49.90% and 55.77%, respectively. This work provides theoretical guidance for the development of superior catalysts and the selection of proper operation parameters for the catalytic pyrolysis of C_5–8 n/iso/cyclo-paraffins from a thermodynamic point of view.