产细菌素屎肠球菌SC-Y112的体外益生性及安全性评价

屎肠球菌SC-Y112是一种具有广谱抗菌性质的产细菌素乳酸菌，为更深入了解其菌株性质，本研究通过模拟胃肠液耐受实验、胆盐耐受实验、抗氧化活性测定、溶血活性测定、明胶液化实验、有害代谢物质检测、耐药性评价及肠球菌毒力基因检测对屎肠球菌SC-Y112的体外益生性质与安全性质进行分析评价。结果表明：屎肠球菌SC-Y112对模拟胃肠液耐受性强，在模拟胃液培养3 h存活率达73.66%，在0.3 g/100 mL的胆盐质量浓度下培养3 h后存活率达56.38%，其发酵24 h上清液总抗氧化能力达35.21 U/mL；此外，屎肠球菌SC-Y112不产生物胺、吲哚以及偶氮还原酶等有害代谢物质，无溶血现象，不溶解明胶，不携带常见肠球菌毒力基因，且对万古霉素敏感。研究结果可为菌株的进一步开发与应用提供科学依据。     

办公建筑LED照明空间的光环境提升需求研究

随着LED照明及其调光调色功能的普及,提高办公人员对室内不同光环境空间的主观体验已成为可能.本文对北京、上海现有办公建筑的办公室、会议室、走廊等光环境空间进行实测,结合对室内人员的主观调研,提出一种面向办公建筑LED照明环境质量提升的客观指标识别方法.在满足现有标准的样本中,以办公室为例,通过主客观数据分析发现,工作面照度和空间亮度更受办公人员关注,空间亮度系数、垂直照度和生理等效照度已成为现有标准外的重要评价指标,体现其等级提升的阈值应分别定为10 lx、150 lx和300 lx.办公建筑中不同光环境场景存在需求差异,均可通过此方法识别归因客观指标及其阈值.研究同时发现,针对主观感受,指标间存在二元耦合关系,其结论进一步丰富光环境评价指标维度并对LED照明的个性化应用提供指导意义.     

Exposure to environmental tobacco smoke during pregnancy and infancy increased the risk of upper respiratory tract infections in infants: A birth cohort study in Wuhan,China

We aimed to evaluate the association of the exposure to environmental tobacco smoke (ETS) during pregnancy and infancy with the risk of upper respiratory tract infections (URTI) in infants based on a Chinese birth cohort study. Among 4178 infants who constituted the final study population, 46.8% experienced URTI in their first year of life. The hazard ratios (HR) and 95% confidence intervals (CI) for the risk of URTI were assessed using Cox regression models. Compared with no ETS during pregnancy, continued ETS during pregnancy was independently associated with a higher risk of URTI (HR: 1.36, 95% CI: 1.13, 1.63) after adjustment for potential confounders and also associated with earlier occurrence of URTI (log-rank P = .002). The association remained consistent across the strata defined according to maternal age, number of siblings, sex, and breastfeeding. Exposure to ETS during infancy was associated with URTI only among infants who were breastfed for less than 12 months (P for interaction < 0.05).Furthermore, infants exposed to ETS during both pregnancy and infancy showed the highest HR of 1.46 (95% CI: 1.16, 1.85) for URTI. Efforts should be made to protect pregnant women and infants from the adverse effects of indoor and outdoor ETS.     

The protein properties of germinated naked barley with infrared and hot air-drying and its noodle-making potential

The naked barley was germinated and then carried out with hot air- or infrared drying to explore the physicochemical and functional properties of protein isolated from barley. Moreover, the relationship between protein and the noodles made from wheat and germinated barley flour was evaluated. It was found that germination affected the protein properties, and the protein properties were correlated with the properties of noodles. The content of β-sheet in protein was first increased and then decreased with germination time increased, and the protein had larger emulsification and foaming properties. Besides, the protein isolated from hot air-dried germinated barley had higher gelatinisation enthalpy and secondary structure content. Furthermore, the wheat and germinated barley mixed noodles had increased elasticity and cohesiveness and reduced viscosity and water absorption. The hardness of noodles showed was positively correlated with water absorption capacity, and the extensibility of cooked noodles was positively correlated with the foaming capacity of proteins.     

2-Hydroxy-4-methoxybenzaldehyde inhibits the growth of Aspergillus flavus via damaging cell wall,cell membrane,manipulating respiration thus creating a promising antifungal effect on corn kernels

This study investigated the antifungal activity and the potential antifungal mechanisms of 2-hydroxy-4-methoxybenzaldehyde (HMB) against Aspergillus flavus (A. flavus). The minimum inhibitory concentration (MIC) of HMB in preventing spore germination was 70 μg mL⁻¹. HMB at MIC disrupted cell wall integrity by reducing the number of septa by 86.66% (P < 0.05) in mycelia and increased cell membrane permeability by about 14-fold (P < 0.05) evidenced by propidium iodide (PI) staining. Furthermore, HMB at MIC inhibited respiration by 33.33%. These results revealed that the antifungal activity of HMB against A. flavus could be attributed to the damaged cell wall integrity, cell membrane permeability and respiration metabolism. What’s more, A. flavus was completely restrained in corn kernels due to HMB. Therefore, HMB could be applied as an effective antifungal agent.     

Improvement of the quality stability of vacuum-packaged fermented fish (Suanyu) stored at room temperature by irradiation and thermal treatments

To evaluate the effects of irradiation and thermal treatments on the quality characteristics of the vacuum-packaged low-salted fermented fish (Suanyu) during 90-day storage, thermal-treated group (TTG), irradiated-treated group (ITG) and non-treated group (CG) were prepared. The results showed that total viable counts reduced by 4.49 and 4.67 log CFU/g after thermal and irradiation treatments, respectively, and no coliforms and pseudomonas growth occurred during storage. Compared with CG, lower levels in L*, springiness, chewiness of TTG and higher levels in L*, b* and chewiness of ITG were detected after 90-day storage. Total biogenic amines content was significantly reduced in ITG compared with CG and TTG (P < 0.05). Both irradiation and thermal treatments have the potential to maintain quality of Suanyu during room storage. Compared with irradiation, thermal treatment could better stabilise the free amino acids and volatile compounds of Suanyu during room storage, but had some negative effects on texture quality.     

钢管RPC边框密肋复合剪力墙轴压性能研究

为研究新型钢管RPC边框密肋复合剪力墙的轴压性能,基于统一强度理论,考虑中间主应力及拉压异性效应,推导出此类构件的轴压承载力计算公式并进行试验验证;采用有限元分析软件ABAQUS,建立钢管RPC边框密肋复合剪力墙的有限元模型,对轴压力学性能进行分析,探讨了中间主应力、钢管壁厚和高宽比对构件轴压承载力的影响.结果表明:钢管RPC边框密肋复合剪力墙具有较高的轴压承载力,ABAQUS数值模拟结果与理论分析结果吻合良好,同时验证了理论计算方法的准确性及有限元模型的可靠性.最后总结分析荷载位移曲线与应力曲线的变化规律,可知钢管RPC边框密肋复合剪力墙表现出良好的协同工作能力.     

Electrostatic-lenses position-sensitive TOF MCP detector for beam diagnostics and new scheme for mass measurements at HIAF

A foil–microchannel plate(MCP) detector,which uses electrostatic lenses and possesses both good position and timing resolutions, has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China. Characterized by low energy loss and good performances of timing and position measurements, it would be located at focal planes in fragment separator HFRS for position monitoring, beam turning, Bρ measurement, and trajectory reconstruction. Moreover, it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(Bρ-△E-TOF) method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis. Most importantly, the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci, and position measurements at a dispersive focus of HFRS, thus making it possible to use two complementary mass measurement methods [isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(Bρ-TOF) at the beam-line HFRS] in one single experimental run.     

碱度对包钢高炉渣物理性能的影响

摘要：为探明二元碱度对包钢高炉渣物理性能的影响机理，基于包钢7号高炉渣化学组成，添加纯试剂CaO、SiO2调整炉渣的二元碱度。通过实验研究二元碱度对包钢7号高炉渣熔化温度、黏度和熔化性温度的影响规律；同时采用Factsage70热力学软件，计算了不同碱度下炉渣的液相线温度和热焓值。结果表明：随着碱度升高，炉渣熔化温度不断升高，黏度和熔化性温度先降低后升高，碱度在1.1～1.3之间，碱度每提高0.1，炉渣半球温度提高4.67℃，软熔区间为3.33～4.60℃；碱度在1.1～1.4之间，1450℃以上炉渣黏度均低于0.5Pa·s，流动性良好；Factsage7.0计算结果表明：随着碱度的升高，炉渣的液相线温度不断升高，热焓值不断降低。综合考虑碱度对包钢炉渣熔化温度、熔化性温度、热焓和黏度的影响规律，建议包钢高炉渣的碱度应控制在1.1～1.3之间。