锡偶联星形嵌段苯乙烯-异戊二烯-丁二烯三元共聚物的制备及表征

采用阴离子聚合法成功制备了锡偶联星形嵌段苯乙烯(St)-异戊二烯(Ip)-丁二烯(Bd)三元共聚物。通过核磁共振、气相色谱、凝胶渗透色谱、透射电镜、动态力学分析等方法表征材料的结构与性能,并与通用橡胶进行性能对比。结果表明,St含量低于30%时,共聚物趋于无规分布,St含量高于35%时,苯乙烯嵌段结构产生,随着St含量的增加,共聚物侧基结构含量下降;三元共聚中St,Ip,Bd的转化率随总转化率的增加而逐渐增大; St含量较低时,共聚物微观相态均一,随St含量的增大,微观相态产生相分离,损耗峰向高温移动,宽度略有增加;嵌段共聚物的物理力学性能与其他橡胶材料相当,抗湿滑性优于通用胶,滚动阻力小于通用胶,是一种理想的轮胎胎面用橡胶材料。

Numerical Simulation of Axial Inflow Characteristics and Aerodynamic Noise in a Large-Scale Adjustable-Blade Fan

Numerical simulation are conducted to explore the characteristics of the axial inflow and related aerodynamic noise for a large-scale adjustable fan with the installation angle changing from−12°to 12°.In such a range the maximum static(gauge)pressure at the inlet changes from−2280 Pa to 382 Pa,and the minimum static pressure decreases from−3389 Pa to−8000 Pa.As for the axial intermediate flow surface,one low pressure zone is located at the junction of the suction surface and the hub,another is located at the suction surface close to the casing position.At the outlet boundary,the low pressure is negative and decreases from−1716 Pa to−4589 Pa.The sound pressure level of the inlet and outlet noise tends to increase monotonously by 11.6 dB and 7.3 dB,respectively.The acoustic energy of discrete noise is always higher than that of broadband noise regardless of whether the inlet or outlet flow surfaces are considered.The acoustic energy ratio of discrete noise at the inlet tends to increase from 0.78 to 0.93,while at the outlet it first decreases from 0.79 to 0.73 and then increases to 0.84.

Multimodality evoked potentials in patients with delayed encephalopathy after acute carbon monoxide poisoning

Objective： To evaluate the diagnostic and prognostic values in patients with delayed encephalopathy after acute carbon monoxide poisoning. Methods： The tibial nerve somatosensory evoked potentials （SEPs）, vision evoked potentials （VEPs）, and brain stem audition evoked potentials（BAEPs） were performed in 32 healthy adults and 43 patients with delayed encephalopathy after acute carbon monoxide poisoning. Results： This paper indicated abnormalities of tibial nerve SEPs in 31 patients （31/43, 72.1%）, VEPs in 17 patients （17/28, 60.7%）, and BAEPs in 14, patients （14/43, 32.6%）. These results showed that the greatest diagnostic value was SEPs, followed by VEPs and, BAEPs with the lowest sensitivity. Conclusion： Multimodality evoked potentials （EPs） can be used for evaluating the diagnostic and prognostic values in cases of delayed encephalopathy after acute carbon monoxide poisoning.

CNEReg Interprets Ruminant-specific Conserved Non-coding Elements by Developmental Gene Regulatory Network

The genetic information coded in DNA leads to trait innovation via a gene regulatory network(GRN)in development.Here,we developed a conserved non-coding element interpretation method to integrate multi-omics data into gene regulatory network(CNEReg)to investigate the ruminant multi-chambered stomach innovation.We generated paired expression and chromatin accessibility data during rumen and esophagus development in sheep,and revealed 1601 active ruminantspecific conserved non-coding elements(active-RSCNEs).To interpret the function of these activeRSCNEs,we defined toolkit transcription factors(TTFs)and modeled their regulation on rumenspecific genes via batteries of active-RSCNEs during development.Our developmental GRN revealed 18 TTFs and 313 active-RSCNEs regulating 7 rumen functional modules.Notably,6 TTFs(OTX1,SOX21,HOXC8,SOX2,TP63,and PPARG),as well as 16 active-RSCNEs,functionally distinguished the rumen from the esophagus.Our study provides a systematic approach to understanding how gene regulation evolves and shapes complex traits by putting evo-devo concepts into practice with developmental multi-omics data.

Modes of genetic adaptations underlying functional innovations in the rumen

The rumen is the hallmark organ of ruminants and hosts a diverse ecosystem of microorganisms that facilitates efficient digestion of plant fibers.We analyzed 897 transcriptomes from three Cetartiodactyla lineages:ruminants,camels and cetaceans,as well as data from ruminant comparative genomics and functional assays to explore the genetic basis of rumen functional innovations.We identified genes with relatively high expression in the rumen,of which many appeared to be recruited from other tissues.These genes show functional enrichment in ketone body metabolism,regulation of microbial community,and epithelium absorption,which are the most prominent biological processes involved in rumen innovations.Several modes of genetic change underlying rumen functional innovations were uncovered,including coding mutations,genes newly evolved,and changes of regulatory elements.We validated that the key ketogenesis rate-limiting gene(HMGCS2)with five ruminant-specific mutations was under positive selection and exhibits higher synthesis activity than those of other mammals.Two newly evolved genes(LYZ1 and DEFB1)are resistant to Gram-positive bacteria and thereby may regulate microbial community equilibrium.Furthermore,we confirmed that the changes of regulatory elements accounted for the majority of rumen gene recruitment.These results greatly improve our understanding of rumen evolution and organ evo-devo in general.