大气生物气溶胶的源排放与源解析研究进展

2019年新冠肺炎(COVID-19)的全球爆发引起了公众对生物气溶胶的广泛关注。生物气溶胶是大气气溶胶的重要组成部分。生物气溶胶由于具有普通气溶胶的理化性质和本身特有的生物学特性,在全球生态系统、气候变化、空气质量和公共卫生等领域均扮演十分重要的角色。然而,目前学术界对生物气溶胶的研究主要集中在采样监测、消杀防护以及其环境与健康效应等方面,关于源特性研究相对滞后。基于此,聚焦大气中微生物的来源现状,综述了最近20年来生物气溶胶的自然源和人为源排放特性研究进展,并阐述了影响源排放和输送过程的主要因素(如生物地理区域、土地利用类型和环境因素等),探讨了当前生物气溶胶的各种源解析方法。最后,给出了生物气溶胶来源下一步的研究展望,以期为深入理解生物气溶胶的来源、输送与变化机理,更好地评估大气微生物污染水平与监控病原体的气溶胶传播提供参考。     

论新型高层次人才及其培养

高层次人才在当今社会有其特定的内涵、特殊的作用，现代科技和社会对高层次人才有着新的需求及要求。科技兴国、人才强国战略的实施离不开新型高层次人才。新型高层次人才的培养及其作用的充分发挥，主要依靠符合时代发展要求、注重复合型知识结构和精品倍出的现代高水平高等教育。为此，教育理念、人才培养观、培养模式、培养重心应实现相应转变。     

GICL型鼓形齿联轴器的研制

分析了国内外鼓形齿式联轴器技术的发展和特点，介绍了GICL型鼓形齿式联轴器的研制过程。     

Soluble Epoxide Hydrolase Blockade after Stroke Onset Protects Normal but Not Diabetic Mice

Soluble epoxide hydrolase (sEH) is abundant in the brain, is upregulated in type 2 diabetes mellitus (DM2), and is possible mediator of ischemic injury via the breakdown of neuroprotective epoxyeicosatrienoic acids (EETs). Prophylactic, pre-ischemic sEH blockade with 4-[[trans-4-[[(tricyclo[3.3.1.13,7]dec-1-ylamino)carbonyl]amino]cyclohexyl]oxy]-benzoic acid (tAUCB) reduces stroke-induced infarct in normal and diabetic mice, with larger neuroprotection in DM2. The present study tested whether benefit occurs in normal and DM2 mice if tAUCB is administered after stroke onset. We performed 60 min middle cerebral artery occlusion in young adult male C57BL mice divided into four groups: normal or DM2, with t-AUCB 2 mg/kg or vehicle 30 min before reperfusion. Endpoints were (1) cerebral blood flow (CBF) by laser Doppler, and (2) brain infarct at 24 h. In nondiabetic mice, t-AUCB reduced infarct size by 30% compared to vehicle-treated mice in the cortex (31.4 ± 4 vs. 43.8 ± 3 (SEM)%, respectively) and 26% in the whole hemisphere (26.3 ± 3 vs. 35.2 ± 2%, both p < 0.05). In contrast, in DM2 mice, tAUCB failed to ameliorate either cortical or hemispheric injury. No differences were seen in CBF. We conclude that tAUCB administered after ischemic stroke onset exerts brain protection in nondiabetic but not DM2 mice, that the neuroprotection appears independent of changes in gross CBF, and that DM2-induced hyperglycemia abolishes t-AUCB-mediated neuroprotection after stroke onset.     

Visceral Adipose Tissue Displays Unique Metabolomic Fingerprints in Obesity,Pre-Diabetes and Type 2 Diabetes

Visceral adipose tissue (VAT) metabolic profiling harbors the potential to disentangle molecular changes underlying obesity-related dysglycemia. In this study, the VAT exometabolome of subjects with obesity and different glycemic statuses are analyzed. The subjects (n = 19) are divided into groups according to body mass index and glycemic status: subjects with obesity and euglycemia (Ob+NGT, n = 5), subjects with obesity and pre-diabetes (Ob+Pre-T2D, n = 5), subjects with obesity and type 2 diabetes under metformin treatment (Ob+T2D, n = 5) and subjects without obesity and with euglycemia (Non-Ob, n = 4), used as controls. VATs are incubated in culture media and extracellular metabolite content is determined by proton nuclear magnetic resonance (¹H-NMR). Glucose consumption is not different between the groups. Pyruvate and pyroglutamate consumption are significantly lower in all groups of subjects with obesity compared to Non-Ob, and significantly lower in Ob+Pre-T2D as compared to Ob+NGT. In contrast, isoleucine consumption is significantly higher in all groups of subjects with obesity, particularly in Ob+Pre-T2D, compared to Non-Ob. Acetate production is also significantly lower in Ob+Pre-T2D compared to Non-Ob. In sum, the VAT metabolic fingerprint is associated with pre-diabetes and characterized by higher isoleucine consumption, accompanied by lower acetate production and pyruvate and pyroglutamate consumption. We propose that glucose metabolism follows different fates within the VAT, depending on the individuals’ health status.     

Highly Thermal Stable Polyimides Applied in Flexible Resistive Memory

Flexible memory devices are one of the most crucial elements in the wearable electronics. In this work, polyimides (PIs)-based flexible resistive memory devices with an excellent thermal and mechanical durability are demonstrated. Four kinds of functional PIs are derived from the heterocyclic diamines including 2,6-diaminodibenzo-p-dioxin (OODA) and 2,6-diaminothianthrene, and dianhydrides including 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride. PI with diamine of OODA and dianhydride of 6FDA (PI(OODA_6FDA)) possesses outstanding thermal and mechanical properties with a high glass transition temperature of 352 °C, a low coefficient of thermal expansion of 28.1 ppm K⁻¹, and a high elongation at break of 10%. In addition, PI(OODA_6FDA)-based memory shows write-once-read-many behavior with a high on/off current ratio of 10⁶ and a stable data retention, attributed to the donor–acceptor charge transfer between the polymer chains. The retained current levels at a low resistive state can be observed even with thermal treatment at 200 °C for 24 h or 1000 times cyclic bending at a bending radius of 5 mm. These results demonstrate the potential of heterocyclic PIs for flexible resistive memory.     

管模工艺的优化

管模是生产离心球墨铸铁管的模具,其毛坯的锻造成型非常困难。本文介绍了管模锻造工艺的优化过程。采用优化后的工艺,解决了管模在锻造生产中出现的各种问题,使管模的成品率大幅提高。同时也为长筒型锻件的成型提供了可靠的参考依据。     

铜管内部阴极保护电位分布公式探讨

简述了管道内部阴极保护时电位分布公式的推导过程，重点推导和分析了双点阳极时其电位公式，并与文献中的同类公式进行了比较，同时，用该公式检验了试验结果。     

灰铁铸件牌号要求与熔炼配料选择

由于铸件壁厚对其性能有明显影响，牌号要求相同、壁厚不同的灰铁铸件必须采用不同的成分和配料。介绍不同灰铁铸件牌号标准的对照，并用生产实例说明如何根据图纸牌号要求、铸件结构和使用性能要求选择化学成分控制标准和熔炼配料。     

B113－2型低汽／气比CO高温变换催化剂的研制

介绍了Ｂ１１３－２Ｍ低汽／气比ＣＯ高温变换催化剂的研制方法及其特点．实验室测试表明，Ｂ１１３－２型催化剂具有堆密度低、运行强度高、选择性好、抗沸水性能优、本体含硫低及低温活性好等优点．