快速检测SEP在手术中脊髓监护的应用

介绍了利用体感诱发电位进行手术中脊髓监护的方法，介绍了手术中脊髓监护的原理及实验系统的构成，给出了利用伪随机序列技术实现快速检测体感诱发电位的算法，实验结果显示，本文的研究较传统方法有一定,值得进一步研究。     

新型皮肤美白剂的研究进展

从抑制黑色素形成、转移以及促进黑色素从表皮脱落等方面对新型皮肤美白剂及其作用机制进行了简要评述。     

临床致病菌整合子检测及耐药基因盒序列分析

目的对临床菌株中的第一类整合子分布及其耐药基因盒的结构特征进行分析。方法应用PCR方法检测33株临床菌株中的第一类整合酶基因intI，并对intI阳性菌株整合的耐药基因进行测序及序列分析。结果33株临床菌株（100％）均为第一类整合酶基因阳性。耐药基因盒特异PCR扩增发现，29株菌得到1913bp的扩增产物，2株得到1664bp的产物，1株得到1009bp的产物，1株得到1913bp和1009bp两种不同产物。序列分析结果表明，1913bp的扩增产物携带基因盒dhfr、orfF和aadA2，1664bp的扩增产物携带基因盒aadA5和dfr17，1009bp的扩增产物携带基因盒aadA2，aadA2和aadA5均为编码对氨基糖苷类抗生素产生耐药的基因盒，dhfr和dfr17均为编码对磺胺类药物甲氧苄氨嘧啶产生耐药的基因盒；orfF为未知功能的开放阅读框。结论第一类整合子介导的耐药基因广泛存在于临床致病细菌中，提示要加强对耐药基因在细菌种属间水平转移的监测工作。     

Viable but non-culturable state and toxin gene expression of enterohemorrhagic Escherichia coli O157 under cryopreservation

As major food-borne pathogens worldwide, Escherichia coli are capable of toxin production directly causing severe human disease. However, routine methods are incapable of detecting viable but non-culturable (VBNC) bacteria in food products and raw materials, leading to false-negative identification. In this study, VBNC E. coli O157 strains were acquired after cryopreservation at −20 °C, with and without freeze-thawing; morphology was observed to be of shorter rod-shape, and toxin expression remained at relatively high levels. PMA-PCR assay for VBNC detection was also validated. Therefore, these results suggest that VBNC E. coli O157 strains may represent a strong threat to public health and food safety.     

Identification of major matrix metalloproteinase-20 proteolytic processing products of murine amelogenin and tyrosine-rich amelogenin peptide using a nuclear magnetic resonance spectroscopy based method

ObjectiveThe aim of this study was to identify major matrix metalloproteinase-20 (MMP20) proteolytic processing products of amelogenin over time and determine if the tyrosine-rich amelogenin peptide (TRAP) was a substrate of MMP20.DesignRecombinant¹⁵N-labeled murine amelogenin and ¹³C,¹⁵N-labeled TRAP were incubated with MMP20 under conditions where amelogenin self-assembles into nanospheres. Digestion products were fractionated by reverse-phase high-performance liquid chromatography at various time points. Product identification took advantage of the intrinsic disorder property of amelogenin that results in little change to its fingerprint ¹H-¹⁵N heteronuclear single-quantum coherence nuclear magnetic resonance spectrum in 2% acetic acid upon removing parts of the protein, allowing cleavage site identification by observing which amide cross peaks disappear.ResultsThe primary product in five out of the six major reverse-phase high-performance liquid chromatography bands generated after a 24 h incubation of murine amelogenin with MMP20 were: S55-L163, P2-L147, P2-E162, P2-A167, and P2-R176. After 72 h these products were replaced with five major reverse-phase high-performance liquid chromatography bands containing: L46-A170, P2-S152, P2-F151, P2-W45, and short N-terminal peptides. TRAP was completely digested by MMP20 into multiple small peptides with the initial primary site of cleavage between S16 and Y17.ConclusionsIdentification of the major MMP20 proteolytic products of amelogenin confirm a dynamic process, with sites towards the C-terminus more rapidly attacked than sites near the N-terminus. This observation is consistent with nanosphere models where the C-terminus is exposed and the N-terminus more protected. One previously reported end-product of the MMP20 proteolytic processing of amelogenin, TRAP, is shown to be an in vitro substrate for MMP20.     

Flash memory devices and bistable nonvolatile resistance switching properties based on PFO doping with ZnO

In this study, poly(9,9-dioctylfluorene-2,7-diyl) (PFO) was synthesized through the Suzuki reaction, and it was characterized. A sandwich type memory device based on PFO and PFO:ZnO, was fabricated using rotary-coating technology. I–V characteristics of the device were studied, and the effects of ZnO nanoparticle (NP) doping content on the performances of the device were discussed. The best doping content of ZnO NPs was found by processing the experimental results (4.76 wt%). Also, the stability of the device was tested, and it was found that the device remained stable after a long testing period. Furthermore, the switching mechanism of the device was discussed.

In this study, poly(9,9-dioctylfluorene-2,7-diyl) (PFO) was synthesized through the Suzuki reaction, and it was characterized.     

Copper-catalyzed intramolecular cross dehydrogenative coupling approach to coumestans from 2′-hydroxyl-3-arylcoumarins

A copper-catalyzed intramolecular cross dehydrogenative C–O coupling reaction of 2′-hydroxyl-3-arylcoumarins was developed. This protocol provided a facile and efficient strategy for the construction of natural coumestans and derivatives in moderate to high yields. This transformation exhibited good functional group compatibility and was amenable to substrates with free phenolic hydroxyl groups.

A copper-catalyzed intramolecular cross dehydrogenative C–O coupling reaction of 2′-hydroxyl-3-arylcoumarins was developed.     

Thermal management for a tube–shell Li-ion battery pack using water evaporation coupled with forced air cooling

A novel battery thermal management system (BTMS) based on water evaporation (WE) and air-cooling (AC) for a tube–shell Li-ion battery (LIB) pack is designed. A sodium alginate (SA) film with a higher water content above 99% is fortified by adding polyethylene (PE) fibers. The air flow and PE-fiber composite sodium alginate (PECSA) film are both used to control the temperature of the battery pack. Results show that the maximum temperature of the battery pack can be controlled below 32 °C, when WE coupled with AC is used at a discharge rate of 1.8C within a discharge time of 1000 s. This method yields the highest performance of thermal management. The experimental results validate the numerical data, confirming that the design of WE combined with AC helps prevent overheating of a battery pack. This work also provides an automatic refilling system to solve the dehydration problem of the PECSA film.

A novel battery thermal management system (BTMS) based on water evaporation (WE) and air-cooling (AC) for a tube–shell Li-ion battery (LIB) pack is designed.     

Jatropha curcas (Linn) leaf extract –a possible alternative for population control of Rhipicephalus(Boophilus) annulatus

ObjectiveTo study the effect of ethanolic extract of leaves of the plant Jatropha curcas as a step towards developing a safe and ecofriendly therapeutic agent to combat the problems of tick and tick-borne diseases.MethodsPulverised leaves of J. curcas were subjected to soxhlet extraction using ethanol. The ethanolic extract of J. curcas at different dilutions such as, 50, 60, 70, 80, 90 and 100 mg / ml were tested against ticks using adult immersion test. The per cent adult mortality, inhibition of fecundity and hatching of laid ova were studied.ResultsThe extract caused significant blocking of hatching of the laid ova by the treated ticks.ConclusionsEclosion blocking effect of J. curcas extract is a promising property of the plant that can be utilized for controlling the population of ticks.