晶体管镀金可伐(Fe-Ni-Co合金)引线腐蚀断裂原因的研究

基于模型分析,研究了镀金可伐引线在各种缺陷组合方式下的偶合系统在静、动态3％NaCl溶液中的腐蚀行为。应用OCC理论阐述了蚀孔的形成和形貌特征。大气环境下镀金可伐引线的腐蚀是以偶合腐蚀为起因,具有闭塞小孔腐蚀特征的局部腐蚀。中性介质的实验结果与实际断腿样品在形貌等各方面均十分相符,这支持了上述观点。     

β-Galactosidase with transgalactosylation activity from Lactobacillus fermentum K4

The LacLM β-galactosidase of Lactobacillus fermentum K4 is encoded by 2 consecutive genes, lacL (large subunit) and lacM (small subunit), that share 17 overlapping nucleotides. Phylogenetic analysis revealed that this enzyme was closely related to other Lactobacillus β-galactosidases and provided significant insight into its common and distinct characteristics. We cloned both the lacL and lacM genes of L. fermentum K4 and heterologously expressed each in Escherichia coli, although the recombinant enzyme was only functional when both were expressed on the same plasmid. We evaluated the enzymatic properties of this species-specific LacLM β-galactosidase and discovered that it acts as both a hydrolase, bioconverting lactose into glucose and galactose, and a transgalactosylase, generating prebiotic galacto-oligosaccharides (GOS). The recombinant β-galactosidase showed a broad pH optimum and stability around neutral pH. The optimal temperature and Michaelis constant (K_m) for the substrates o-nitrophenyl-β-d-galactopyranoside and lactose were, respectively, 40°C and 45 to 50°C and 1.31 mM and 27 mM. The enzyme activity was stimulated by some cations such as Na⁺, K⁺, and Mg²⁺. In addition, activity was also enhanced by ethanol (15%, wt/vol). The transgalactosylation activity of L. fermentum K4 β-galactosidase effectively and rapidly generated GOS, up to 37% of the total sugars from the reaction. Collectively, our results suggested that the β-galactosidase from L. fermentum K4 could be exploited for the formation of GOS.     

闭式冷却塔中空气与喷淋水同向和逆向流动的流阻试验研究

一些高效逆流闭式冷却塔盘管管外的空气流动和喷淋水的流动方向相同(顺流),其空气流动阻力的规律性尚待进一步探索,本文对此进行了试验研究。设计构建了相关的试验装置、试验件,进行了一系列的试验。为便于对比,分别针对盘管管外的空气流动和喷淋水的流动方向同向以及逆向(逆流)进行了试验。通过改变喷淋水的喷淋量和空气的流速,得到了相关的空气流动阻力的规律性。试验表明,顺流型式比逆流型式的空气流动阻力大为降低,逆流型式存在空气流动阻力的突增点,顺流型式不存在阻力的突增点。     

Theragnostic Efficacy of K18 Response in Alcohol Use Disorder with Clinically Significant Fibrosis Using Gut-Liver Axis

(1) Background: Fibrosis in early-stage alcohol-associated liver disease (ALD) is commonly under-diagnosed in routine clinical practice. This study characterized the liver-injury and cell death response in alcohol use disorder (AUD) patients with ALD who also exhibited fibrosis and assessed the efficacy of standard of care (SOC) treatment in the improvement in liver injury. (2) Methods: Forty-eight heavy-drinking AUD patients aged 21–65 yrs. without clinical manifestations of liver injury were grouped by Fibrosis-4 (FIB-4) score, as negative (Gr.1 < 1.45, n = 21) or positive (Gr.2 ≥ 1.45, n = 27). Patients received 2-weeks (2 w) inpatient SOC. Data on demographics, drinking patterns, liver-injury, immune markers, and liver cell death (K18s) markers were analyzed at baseline (BL) and after 2 w SOC. (3) Results: Lifetime drinking (LTDH, yrs.) and acute heavy drinking (Heavy Drinking Days Past 90 Days [HDD90]) markers were significantly higher in Gr.2 vs. Gr.1. BL ALT, AST, AST:ALT and K18M65 were considerably higher in Gr.2. Dysregulated gut dysfunction and elevated immune activity were evident in Gr.2 characterized by TNF-α, IL-8 and LPS levels. After SOC, Gr.2 showed improvement in AST, ALT, AST/ALT ratio; and in the K18M65, K18M30 and K18M65/M30 ratio vs. Gr.1. The true positivity of BL IL-8 response to predict the improvement in K18M65 to normal levels among Gr.2 patients against those who did not have improvement after 2 w SOC was very high (AUROC = 0.830, p = 0.042). (4) Conclusions: Gut dysfunction, elevated cytokine response and necrotic liver cell death were elevated in AUD patients with early-stage ALD. K18 showed promise as a predictive theragnostic factor to differentiate among the AUD patients with early-stage ALD and baseline fibrosis who had improvement in liver injury against those who did not, by the levels of baseline IL-8.     

快速高准确度的闪烁探测技术

闪烁探测器具有探测效率高和适于多种条件下应用等优点。但在高计数率测量时,光电倍增管出现的疲劳现象难以克服,其长期稳定性也较差。 本文提出一种措施,使闪烁探测器在每秒10~5个计数脉冲下获得了高的精度和好的稳定性。这项技术已经应用于FT-1型核子低含沙量计中。经测试表明,当每次测量历时为100秒时该仪器的计数精度和8小时长期     

退火炉自动控制系统设计

山东烟台钢管总厂冷拔分厂退火炉自动控制系统的设计以微机、智能仪表、变频调速器为主,具有控制精度高、降低消耗、操作维修方便、提高劳动生产率等特点。     

国家烟草专卖局现行职能缺陷刍议

2008年,国务院国家烟草专卖局调整为工业和信息化部管理的副部级国家局.这次调整对国家烟草专卖局的职责有所优化,但并未能根本触动"政企合一"的体制,缺陷明显,政策制定和贯彻落实时有冲突.     

R407C组分分离特性实验研究

针对H407C三元混合工质的非共沸特性,在组分分离实验台上进行了相应的分离实验。结果表明：不同的分离器在不同的加热功率下的分离效果不同;经过组分分离实验,R407C的组分有明显的改变,并且在一定的实验工况下可以得到较好的分离效果。经分离后,轻、重组分最高比例可达48．71％和98．23％。     

Cryogenic Exfoliation of 2D Stanene Nanosheets for Cancer Theranostics

Stanene(Sn)-based materials have been extensively applied in industrial production and daily life,but their potential biomedi-cal application remains largely un...