Characterization of 3D elastic porous polydimethylsiloxane (PDMS) cell scaffolds fabricated by VARTM and particle leaching

In this study, elastic porous polydimethylsiloxane (PDMS) cell scaffolds were fabricated by vacuum‐assisted resin transfer moulding (VARTM) and particle leaching technologies. To control the porous morphology and porosity, different processing parameters, such as compression load, compression time, and NaCl particle size for preparing NaCl preform, were studied. The porous structures of PDMS cell scaffolds were characterized by scanning electron microscopy (SEM). The properties of PDMS cell scaffolds, including porosity, water absorption, interconnectivity, compression modulus, and compression strength were also investigated. The results showed that after the porogen–NaCl particles had been leached, the remaining pores had the sizes of 150–300, 300–450, and 450–600 μm, which matched the sizes of the NaCl particles. The interconnectivity of PDMS cell scaffolds increases with an increase in the size of NaCl particles. It was also found that the smaller the size of the NaCl particles, the higher the porosity and water absorption of PDMS cell scaffolds. The content of residual NaCl in PDMS/NaCl scaffolds reduces under ultrasonic treatment. In addition, PDMS scaffolds with a pore size of 300–450 μm have better mechanical properties compared to those with pore sizes of 150–300 and 450–600 μm. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42909.     

The Role of a Nonribosomal Peptide Synthetase in l‐Lysine Lactamization During Capuramycin Biosynthesis

Capuramycins are one of several known classes of natural products that contain an l ‐Lys‐derived l ‐α‐amino‐?‐caprolactam (l ‐ACL) unit. The α‐amino group of l ‐ACL in a capuramycin is linked to an unsaturated hexuronic acid component through an amide bond that was previously shown to originate by an ATP‐independent enzymatic route. With the aid of a combined in vivo and in vitro approach, a predicted tridomain nonribosomal peptide synthetase CapU is functionally characterized here as the ATP‐dependent amide‐bond‐forming catalyst responsible for the biosynthesis of the remaining amide bond present in l ‐ACL. The results are consistent with the adenylation domain of CapU as the essential catalytic component for l ‐Lys activation and thioesterification of the adjacent thiolation domain. However, in contrast to expectations, lactamization does not require any additional domains or proteins and is likely a nonenzymatic event. The results set the stage for examining whether a similar NRPS‐mediated mechanism is employed in the biosynthesis of other l ‐ACL‐containing natural products and, just as intriguingly, how spontaneous lactamization is avoided in the numerous NRPS‐derived peptides that contain an unmodified l ‐Lys residue.     

Interface trap effect on the transient characteristics of a photovoltaic InSb infrared detector

The transient characteristics can be significantly affected by the interface trap. In order to reveal the intrinsic mechanism and provide some references for the design of detectors, the interface trap effect on the transient characteristics of a back-illuminated photovoltaic InSb infrared detector is studied with two-dimensional simulations. The relationships between interface traps and some key physical parameters, such as the hole concentration, the recombination rate and the electric field, are analyzed to reveal the intrinsic mechanisms of the influence of the interface traps on the transient characteristics. Studies show that with the increase of the interface trap density, the recombination rate and the electric field near the interface increase, the hole concentration decreases, and the “black holes” in current density distribution appear and move forward to the pn junction. And the transient photoresponse decreases with the increase of the interface trap density.     

丙烯酸β-羟丙酯/乙烯基吡咯烷酮共聚物及其水凝胶的合成和温敏行为的研究

用自由基共聚法合成了一系列 β-羟丙酯 (β-HPAT)和乙烯基吡咯烷酮 (NVP)的共聚物及其水凝胶。发现共聚物的水溶液有敏锐的温敏行为 ,最低汇溶温度 (LCST)随 NVP含量的增加而升高 ,随着反应单体总浓度的增加 ,相变敏锐性下降且 LCST也随之下降。通过考察水凝胶的溶胀率 (SR) ,发现共聚凝胶在适当的单体浓度、交联剂浓度和较宽的单体浓度配比范围内 ,有较灵敏的温敏行为     

1,4—丁二醇的生产应用及市场前景

介绍了１,４－丁二醇的性质、生产方法以及国内外１,４－丁二醇的生产消费及市场情况,提出了发展我国１,４－丁二醇产品的建议。     

烟酸的应用与生产方法

介绍了烟酸的性质、应用及其生产方法,并分析了国内外市场对烟酸的需求情况。     

年产120吨聚丙烯酸钠絮凝剂的工艺设计与投产

介绍了新开发的生产工艺过程及工艺条件,对120吨/年的工厂设备选型、工厂经济分析及其应用效果作了简要评述。     

低温超导磁体的粘接技术

1　前言我所设计制造的低温超导磁体中 ,有螺旋形的中心螺线管线圈 ,圆环形的极向场线圈 ,Ｄ形的纵场线圈 ,它们的截面结构基本相同。磁体中层与层之间 (又称层间绝缘 ) ,匝与匝之间 (匝间绝缘 )及整个磁体的外围 (对地绝缘 ) ,都是粘接结构。说明粘接技术在低温超导磁体中具有多种用途 ,可实现多种目的 ,包括连接、紧固、密封、填充、导热和绝缘等。在有些有特殊要求的低温超导磁体的层间或匝间 ,还垫有由胶粘剂粘接的垫块。2　超低温胶粘剂的选用超低温胶粘剂是指能在超低温条件(- 2 69℃ ,- 1 96℃ ,- 1 83℃ )下使用 ,并保持足够粘接强…     

焦炭强度指标间的关系研究

通过１０种单种煤炼制的７ｋｇ焦炉焦,７个钢铁公司的入炉焦和风口焦,测定他们的米库姆转鼓强度、Ｉ－转鼓强度、显微强度、结构强度、抗拉强度和焦炭光学组织,从中揭示他们之间的内在关系。