关键词： 钨材料   韧脆转变温度(DBTT)   四点弯曲试验(4PBT)   加载速率  

摘要： 针对聚变装置中钨材料的性能评价问题,采用四点弯曲试验(4PBT)方法对钨材料的韧脆转变温度(DBTT)进行了测试和分析。首先,基于对四点弯曲过程的应变率和强度随温度变化的分析获得了商用轧制纯钨的DBTT。结果表明,用标准四点弯曲法测得的工业轧制纯钨的DBTT值在150℃以下,低于相同材料的拉伸试验和冲击试验的测量值。然后对比不同加载速率的4PBT和拉伸试验的结果,证实了不同的DBTT测试方法的加载速率依赖性。最后,对测试方法影响DBTT测量的原因进行了分析和讨论。

关键词： Atmospheres   Dynamics   Composition   Jupiter   Atmosphere   Meteorology  

摘要： The 24 degrees N jet borders the North Tropical Belt and North Tropical Zone, and is the fastest prograde jet on Jupiter, reaching speeds above 170 m/s. In this region, observations have shown several periodic convective plumes, likely from latent heat release from water condensation, which affect the cloud and zonal wind structure of the jet. We model this region with the Explicit Planetary hybrid-Isentropic Coordinate model using its active microphysics scheme to study the phenomonology of water and ammonia clouds within the jet region. On perturbing the atmosphere, we find that an upper tropospheric wave develops that directly influences the cloud structure within the jet. This wave travels at a net (eastward) phase speed of similar to 75 m/s in our model, and leads to periodic chevron-shaped features in the ammonia cloud deck. These features travel with the wave speed, and are subsequently much slower than the zonal wind at the cloud deck. This unique morphology of the ammonia cloud, and the slower drift rate, were both observed following the convective outbreak in this region in 2016 and 2020. We find that an upper level circulation is responsible for these cloud features in the aftermath of the convective outbursts. The comparatively slower observed drift rates of these features, relative to the wind speed of the jet, provides constraints on the vertical wind shear above the cloud tops, and we suggest that wind velocities determined from cloud tracking should correspond to a different altitude compared to the 680 hPa pressure level. We also diagnose the convective potential of the atmosphere due to water condensation, and find that it is strongly coupled to the wave.

关键词： 腰痛   针刺   内热针   系统评价   Meta分析  

摘要： 目的运用循证医学方法评价内热针与其他针刺疗法治疗腰痛的疗效比较,评价内热针疗法的应用价值。方法从中国期刊全文数据库(CNKI)、中国科技期刊全文数据库(VIP)、美国国家医学图书馆期刊文献检索系统(Pubmed)、中国生物医学文献服务系统(Sino Med)和万方资源数据库(Wanfang)检索了建库至2021年2月的内热针与其他针刺疗法治疗腰痛病的随机对照试验(RCT)。由2名研究人员根据纳入标准和排除标准独立对文献进行筛选、提取资料、交叉核对,并利用Cochrane系统评价手册评价文献质量并用Rev Man5.3软件制作文献质量评价图,以Stata16软件进行Meta分析。结果共采用14项研究,共计受试者1068例。Meta分析结果显示:有效率[OR=2.02,95%CI(1.47,2.57),P<0.01],视觉模拟疼痛评分(VAS)[MD=-2.08,95%CI(-2.34,-1.81),P<0.01],日本骨科协会(JOA)腰椎评分[MD=5.46,95%CI(4.63,6.29),P<0.01],腰屈曲范围(LFR)[MD=1.78,95%CI(1.04,2.52),P<0.01]。结论内热针较毫针、温针与电针疗法能够明显减轻腰部疼痛,改善腰椎功能。但本研究纳入文献质量不高,治疗效果证据较为有限,尚需更多大样本、多中心、高质量临床随机对照研究以佐证。

摘要： IntroductionLong-term Ulcerative Colitis (UC) increases the risk of colonic dysplasia and colorectal cancer (CRC). We aim to establish whether real-world faecal calprotectin (FCP) data can be used to estimate the cumulative inflammatory burden (CIB) and identify those at risk of dysplasia and *** with left sided or extensive UC of >8 yrs duration, with >1 endoscopy and >1 serial FCP value (from 2005) were extracted from the NHS Lothian IBD registry. Patients with PSC were *** scores based on histology (CIB(H)) or FCP (CIB(FCP)) were calculated based on the method proposed by Choi et al [1]. Patients were categorised into three groups; IBD-associated dysplasia and CRC (IBD-D/CRC n=15), only sporadic adenomas (n=29, excluded from further analysis) and patients who did not develop any type of dysplasia (n=220).To give a more accurate estimation of cumulative inflammation FCP levels were defined as low (n=73) or high (n=162). High CIB(FCP) is equivalent to 5 yrs of a continuous FCP value of ≥250µg/g, a surrogate marker of chronic active *** defined cohort of 264 patients (146 males), with a median age 36 (IQR 27.1-46.9) were *** the CIB(H) score, patients with no dysplasia (n=220) had a median score of 4.7 (IQR 2.7-7.9), compared with patients with IBD-D/CRC (n=15) who had a score of 5.4 (3.5-8.2) (p=0.4405, unpaired two-tailed t-test).The median CIB (FCP) score for patients with no dysplasia was 1804 (883-3689), compared with patients with IBD-D/CRC who had a median score of 2256 (1593-3848) (p=0.4835). The correlation between the two types of CIB scores in identifying risk of IBD-D/CRC was weak (Spearman’s rho=0.296 (p<0.001). In this cohort neither score was able to predict IBD-D/*** give a more accurate estimation of CIB(FCP) the rates of IBD-D/CRC were stratified by FCP levels over time; 73 patients (31.1%) had low CIB(FCP) and 162 (68.9%) had a high CIB(FCP). Using this model, 1/73 (1.4%) in the low CIB(FCP)

关键词： 短波电台   远距离通信   干扰机   干扰路径   降低干扰   干扰源   排障   机载通信系统  

摘要： 机载短波电台容易对机上油量、火警、转速、温度等信号产生干扰,引发故障。排障过程中需要从干扰源、干扰路径、被干扰体等方面进行逐渐排除,降低干扰程度。为此,通过系统分析机载短波电台干扰机上其他系统因素和排除方法,总结排障措施,以提高排障效率。短波电台属于飞机机载通信系统产品的重要组成部分,主要用于空空/空地之间的远距离通信联络。某型俄制短波电台由于产品性能存在缺陷且使用年限较长,已不能满足远距离作训任务需求.

摘要： ~~

关键词： miRNA治疗   癌症   肝炎   心血管疾病   糖尿病  

摘要： microRNAs(miRNAs)是一类内源性、非编码小分子RNAs(约22 nt),在基因表达调控中发挥关键作用。已有研究表明,miRNAs失调是造成多种人类疾病的原因,如癌症、病毒感染及自身免疫性疾病等。补充或抑制miRNAs功能与活性已成为多种疾病治疗的新策略,抗肿瘤miR-34mimics、治疗HCV感染的anti-miR-122等基于miRNAs的治疗方案已进入临床试验。重点就miRNAs治疗在癌症及其他疾病中的最新研究进展进行综述,并对目前开发安全有效miRNAs治疗策略所面临的挑战进行分析。

关键词： Organic acids   Catalysts   Metals   Ligands   Organic reactions  

摘要： The reaction of the hexahydride OsH6(PiPr(3))(2) with a P,Ge,P-germylene-diphosphine affords an osmium tetrahydride derivative bearing a Ge,P-chelate, which arises from the hydrogenolysis of a P-C(sp(3)) bond. This Os(IV)-Ge(II) compound is a pioneering example of a bifunctional catalyst based on the coordination of a sigma-donor acid, which is active in the dehydrogenation of formic acid to H-2 and CO2. The kinetics of the dehydrogenation, the characterization of the resting state of the catalysis, and DFT calculations point out that the hydrogen formation (the fast stage) exclusively occurs on the coordination sphere of the basic metal center, whereas both the metal center and the sigma-donor Lewis acid cooperatively participate in the CO2 release (the rate-determining step). During the process, the formate group pivots around the germanium to approach its hydrogen atom to the osmium center, which allows its transfer to the metal and the CO2 release.

关键词： dysregulation of RNA processing   alternative splicing   therapeutic targeting of alternative splicing   cancer   gastrointestinal malignancies  

摘要： Recent comprehensive genomic studies including single-cell RNA sequencing and characterization have revealed multiple processes by which protein-coding and noncoding RNA processing are dysregulated in many cancers. More specifically, the abnormal regulation of mRNA and precursor mRNA (pre-mRNA) processing, which includes the removal of introns by splicing, is frequently altered in tumors, producing multiple different isoforms and diversifying protein expression. These alterations in RNA processing result in numerous cancer-specific mRNAs and pathogenically spliced events that generate altered levels of normal proteins or proteins with new functions, leading to the activation of oncogenes or the inactivation of tumor suppressor genes. Abnormally spliced pre-mRNAs are also associated with resistance to cancer treatment, and certain cancers are highly sensitive to the pharmacological inhibition of splicing. The discovery of these alterations in RNA processing has not only provided new insights into cancer pathogenesis but identified novel therapeutic vulnerabilities and therapeutic opportunities in targeting these aberrations in various ways (e.g., small molecules, splice-switching oligonucleotides (SSOs), and protein therapies) to modulate alternative RNA splicing or other RNA processing and modification mechanisms. Some of these strategies are currently progressing toward clinical development or are already in clinical trials. Additionally, tumor-specific neoantigens produced from these pathogenically spliced events and other abnormal RNA processes provide a potentially extensive source of tumor-specific therapeutic antigens (TAs) for targeted cancer immunotherapy. Moreover, a better understanding of the molecular mechanisms associated with aberrant RNA processes and the biological impact they play might provide insights into cancer initiation, progression, and metastasis. Our goal is to highlight key alternative RNA splicing and processing mechanisms and their roles

关键词： composite materials   mechanical strength   turbine engine fuel   carbon fiber   alternative jet fuel  

摘要： New commercial and military aircraft components are often manufactured using advanced composite materials. Fuel is stored in the wing and horizontal tail structures of aircraft for prolonged periods of time. The use of alternative turbine engine fuels as substitutes for such kerosene-based fuels as Jet-A is increasing steadily. However, the studies related to effects of the fuels on the composite structure of aircraft are limited in number. This research was meant to investigate the effects that contacting alternative turbine fuels might have on the mechanical properties of a composite structure. Three different test settings were prepared - 0 and 90 degrees orientation tensile and a modified wedge ones. An IM7 8552 unidirectional carbon fiber/epoxy prepreg was used to manufacture test specimens. They were soaked in various kinds of turbine engine fuels: neat Jet-A, 50/50 blend of Jet-A and hydroprocessed renewable jet (HRJ) (Jet-A/HRJ), Fischer-Tropsch (FT), 50/50 blend of synthetic jet fuel S8 and Fischer-Tropsch (FT) (S8/FT), hydrogenated esters and fatty acids (HEFA) fuels, and synthesized iso-paraffin fuels (SIP) for a period of 45 days and then tested. The test data obtained were analyzed to detect any significant degradation of the mechanical properties of test specimens.