Cell Sheet Comprised of Mesenchymal Stromal Cells Overexpressing Stem Cell Factor Promotes Epicardium Activation and Heart Function Improvement in a Rat Model of Myocardium Infarction

Cell therapy of the post-infarcted myocardium is still far from clinical use. Poor survival of transplanted cells, insufficient regeneration, and replacement of the damaged tissue limit the potential of currently available cell-based techniques. In this study, we generated a multilayered construct from adipose-derived mesenchymal stromal cells (MSCs) modified to secrete stem cell factor, SCF. In a rat model of myocardium infarction, we show that transplantation of SCF producing cell sheet induced activation of the epicardium and promoted the accumulation of c-kit positive cells in ischemic muscle. Morphometry showed the reduction of infarct size (16%) and a left ventricle expansion index (0.12) in the treatment group compared to controls (24–28%; 0.17–0.32). The ratio of viable myocardium was more than 1.5-fold higher, reaching 49% compared to the control (28%) or unmodified cell sheet group (30%). Finally, by day 30 after myocardium infarction, SCF-producing cell sheet transplantation increased left ventricle ejection fraction from 37% in the control sham-operated group to 53%. Our results suggest that, combining the genetic modification of MSCs and their assembly into a multilayered construct, we can provide prolonged pleiotropic effects to the damaged heart, induce endogenous regenerative processes, and improve cardiac function.     

基于综合赋权与集对分析的煤炭企业安全评价

安全评价是发现系统风险,提高生产安全性的有效手段。运用集对分析理论对煤炭企业生产安全性进行分析与评价。根据SHEL模型,结合煤炭企业实际对生产中的风险因素进行分析,确定了煤炭企业安全评价指标体系;将熵权法与超标倍数赋权法相组合来确定各评价指标的综合权重,基于集对分析理论构建了煤炭企业安全评价模型。将构建的指标体系和评价模型在平煤集团5个生产矿井进行了应用,结果显示,利用集对分析得到的评价结果与实际情况基本吻合。     

Application of Cudrania tricuspidata leaf extract as a washing agent to inactivate Listeria monocytogenes on fresh-cut romaine lettuce and kale

The present study aimed to examine the antimicrobial activity of silkworm thorn (Cudrania tricuspidata) leaf extract (CTLE) and its application as a washing agent for fresh-cut romaine lettuce and kale. The antimicrobial activities of CTLE at various concentrations against Listeria monocytogenes were determined using disc diffusion and viable cell count assays, and CTLE exhibited strong inactivation of L. monocytogenes. In particular, after the treatment with 0.4% CTLE, the protein content of L. monocytogenes cells was significantly (P < 0.05) decreased from 507.21 to 254.58 μg mL⁻¹, and damaged cells were observed by scanning electron microscopy. CTLE washing resulted in approximately 2-log reduction of microbial growth, similar to that of 0.01% NaOCl. In addition, CTLE washing did not affect the quality of romaine lettuce and kale. Therefore, these results suggest that CTLE is applicable as a new washing agent for inactivating L. monocytogenes on fresh-cut romaine lettuce and kale.     

Pore structure of reactively synthesized nanolaminate Ti3SiC2 alloyed with Al

Ti₃SiC₂ has the unique properties integrating the advantages of metals and ceramics, and good open pore structure when alloyed with Al. In this work, porous Ti₃SiC₂ compounds with different Al/Si atom ratios were prepared through the reactive synthesis of elemental powders at 1300 °C. The results indicate that the phase compositions are determined by Al element mole number, and that the pore structure can be controlled through varying Ti particle size. The MAX phase transits from Ti₃SiC₂ with Al element mole number no more than 0.6 to Ti₃AlC₂ with Al element mole number in the range of 0.8–1.2. When Al element mole number is 0.6, the porous compound has a single MAX phase of Ti₃SiC₂ with uniform microporous structure and high bending strength. Porous Ti₃SiC₂ alloyed with 0.6Al has a slow linear increase rate of 0.0083%/μm in open porosity with increasing Ti particle size, and a strict linear relationship between the maximum aperture and Ti particle size with the increase rate of 0.0342 μm/μm. The pore structure formed by the phase transition mechanism for porous MAX phase has the smallest tortuosity factor compared with that formed by the clearance mechanism and the Kirkendall effect.     

湿法磷酸净化脱砷的研究现状

随着食品、医药及电子行业的不断发展，磷酸及磷酸盐的市场需求量不断增大，并且对磷酸的品质要求也越来越高，尤其是对湿法磷酸中砷杂质的要求，湿法磷酸中砷的含量将直接影响其在磷精细化工领域的应用，因此湿法磷酸中砷的高效、安全去除是亟待解决的一大难题。本文主要对湿法净化磷酸脱砷技术的研究情况进行综述，比较了几种湿法净化磷酸脱砷工艺的优缺点，介绍了较常见的化学沉淀法、结晶法，以及新兴的电沉积法、垂直区域熔融法和微反应器脱砷工艺的应用前景，并指出这些新兴的脱砷工艺将成为今后湿法磷酸的净化脱砷的发展方向，如能解决将这些脱砷工艺在实际中的问题，将会对磷酸工业的发展提供一个更有力的支持。     

荷花山铅锌矿与铜陵地区其它矿床成矿控制因素的对比研究

为了探讨荷花山铅锌矿控矿因素上与铜陵地区其它矿床异同，运用宏、微观相结合，地质观察研究同位素地球化学以及流体包裹体分析相结合的方法，通过地层岩性、地质构造、特定地质体及成矿流体的来源和性质等几个方面与成矿关系的比较，揭示了这种新类型矿床的控矿因素的特点是与岩浆关系不密切的低温热液、角砾岩控矿。得出了这种新类型矿床既具有铜陵地区其它矿床的控矿因素，同时也具有自己独特的控矿因素的结论。     

大统矿业超高水充填开采制浆系统设计研究

煤炭作为我国的主要能源，在国民经济发展中具有不可取代的作用。矿井面临资源枯竭的困境时，尽可能多地采出煤炭是企业存续发展的当务之急。山东省兖州市大统矿业有限公司杨庄煤矿九采区3煤层1997—2005年进行了开采，由于受当时设备和技术的限制，仅回采一分层2.2 m。为挖掘企业潜力，充分利用煤炭资源，采用超高水充填法开采剩余分层和浅部煤炭资源。结合矿井实际情况提出适应矿井的高水充填系统布置方案，在地面建设制浆站，通过专门的设备将材料骨料制成浆液，然后运用管路将浆液输送至采空区进行充填。超高水材料制浆充填系统可服务于九采区全部充填工作面，每小时制浆生产能力为320 m³，每天生产1班8 h，约2 500 m³ 可以满足2个工作面的充填开采需要，极大提高了制浆充填效率，取得了良好的效果和经济社会效益。     

煤巷过断层破碎带施工工艺与支护技术实践

W1313回风顺槽在里程332 m处揭露正断层,对此采取了调整巷道顶板锚网索支护参数,采用圆木大板棚复合支护等措施,并加强了顶板、通风、掘锚机破岩、爆破作业和作业人员的安全管理,确保工作面过断层破碎带时的安全施工。     

某能源公司安全管理效率评价

某能源股份有限公司是我国上市煤炭公司,为评价其安全管理效率,采用数据包络(DEA)分析方法,以员工人数、资产总额、安全生产费为投入指标,以原煤产量、百万吨煤死亡率为产出指标,对其2007—2018年间的安全管理效率进行了评价。结果显示,某能源公司在研究期间的安全管理效率较为低下,但近5年来有提升的趋势,2018年安全管理实现DEA有效;安全管理无效的主要原因为纯技术效率和规模效率低下。为提高安全管理效率,该企业应在安全投入资源的匹配性和安全投入规模的合理性两个方面采取针对性措施。     

煤矿安全监控系统的发展简述

煤矿安全监控系统是煤矿日常安全管理和灾害防治不可或缺的安全装备,然而现有安全监控系统普遍存在网络结构可靠性差、抗干扰能力弱、数字化程度低、兼容性差、智能化水平低等问题。结合监控系统升级改造的具体要求,对我国煤矿安全监测监控系统的现状,包括存在的主要问题进行了论述,并对系统升级改造后的变化及未来的发展趋势进行了探讨。分析表明,基于工业太环网、数字总线双重冗余结构的新一代全数字式煤矿安全监控系统集多主通讯、智能传感、电磁兼容等多项关键技术于一体,满足监控系统数字化、智能化以及网络化的升级改造要求,也是未来监控系统的发展趋势。新系统的应用可有效提高煤矿的防灾抗灾能力,为煤矿的安全生产提供保障。