Magnesium-Catalyzed Asymmetric Thia-Michael Addition to α,β-Unsaturated Ketones

We demonstrate the application of chiral magnesium complexes in an asymmetric carbon-sulfur bond-forming reaction. Enantioselective and cost-effective methodology under mild condition for the thia-Michael addition, utilizing an in situ generated chiral dinuclear magnesium-ProPhenol complex, has been developed. The versatility of this protocol is demonstrated with a broad range of thiol nucleophiles and a wide selection of enones. Enantioenriched β-ketosulfides are obtained in good to excellent yields and moderate to excellent enantioselectivity. The presented catalytic system exhibits excellent tolerance for structurally different substrates while maintaining high enantioselectivity. This observation aligns with proposed mechanism, wherein the sulfur atom coordinates to the catalyst in close proximity to the reaction center.     

Metal-organic framework composites for energy conversion and storage

Metal-organic frameworks (MOFs) with orderly porous structure, large surface area, high electrochemical response and chemical tunability have been widely studied for energy conversion and storage. However, most reported MOFs still suffer from poor stability, insufficient conductivity, and low utilization of active sites. One strategy to circumvent these issues is to optimize MOFs via designing composites. Here, the design principle from the viewpoint of the intrinsic relationships among various components will be illuminated to acquire the synergistic effects, including two working modes: (1) MOFs with assistant components, (2) MOFs with other function components. This review introduces recent research progress of MOF-based composites with their typical applications in energy conversion (catalysis) and storage (supercapacitor and ion battery). Finally, the challenges and future prospects of MOF-based composites will be discussed in terms of maximizing composite properties.     

硒肥浓度对藤茶硒含量及生长发育的影响

以多年生木质藤本植物藤茶为材料进行盆栽实验,探讨硒肥浓度对藤茶硒的吸收变化规律及生长发育的影响,优选出适宜的硒肥浓度,为富硒藤茶大规模栽培和开发利用提供依据。结果表明,一定浓度的硒肥对藤茶根、茎、叶的生长具有显著促进作用,并对藤茶的花序重量具有显著影响。随着硒的浓度升高,藤茶硒含量呈现整体升高的规律,硒浓度增大到一定程度时硒含量增加不显著。综合藤茶富硒规律及生长发育的影响可知,富硒藤茶的施硒浓度为5~10 mg/kg,在此浓度范围内硒对藤茶生长发育有积极影响且富硒含量较高。      

香蕉低聚糖的通便功能评价

为比较不同品种香蕉低聚糖的通便功能,选取皇帝蕉(Musa AA Pisang Mas)和粉蕉(Musa ABB Pisang Awak),提取低聚糖后分别设置两种浓度(高剂量组2.5 g/(kg·BW·d)和低剂量组1.25 g/(kg·BW·d)),参考《保健食品检验与评价技术规范(2003版)》中\     

谷胱甘肽添加对贮藏猕猴桃酒香气成分的影响

在以徐香猕猴桃为原料酿造得到的猕猴桃酒中,分别添加25 mg/L和50 mg/L的谷胱甘肽,以不添加谷胱甘肽的猕猴桃酒为对照组,4℃条件下密封贮藏6个月后取样测定各样品的香气成分,分析贮藏后猕猴桃酒香气成分的变化以及添加谷胱甘肽对贮藏猕猴桃酒香气成分的影响。采用顶空固相微萃取（SPME）法进行猕猴桃酒香气成分提取,通过气相色谱-质谱（GC-MS）进行猕猴桃酒香气成分分析。结果表明:从猕猴桃酒中共检测出42种香气成分,主要包括醇类、酯类、酸类以及萜烯类和C₁₃-降异戊二烯衍生物。贮藏6个月后猕猴桃各类香气总量均产生逸散,然而与贮藏后的对照组样品相比,谷胱甘肽添加处理的猕猴桃酒特征香气保持效果更好,香气物质总量更高,25 mg/L和50 mg/L的谷胱甘肽的添加分别可以降低6.68%和46.24%的香气损失,说明谷胱甘肽在猕猴桃酒贮藏阶段的添加更有益于猕猴桃酒的贮藏。      

The effect of oxygen on the epitaxial growth of diamond

We studied the effect of oxygen on the growth quality of diamond epitaxial layers. After oxygen is added during the growth of the diamond epitaxial layer, as the thickness of the epitaxial layer increases, the full width at half maximum of the rocking curve of the (004) plane of diamond epitaxial layer increases continuously, and, in addition, the intensities of both the Raman peaks and the free exciton emission peaks of the diamond epitaxial layer decrease continuously. These experimental results demonstrate that as the thickness of the diamond epitaxial layer increases, the quality of the diamond epitaxial layer degrades. The strong etching effect of the OH radical groups in the plasma on the diamond epilayers leads to the degradation of their crystallinity.     

高性能通用处理器中的漏电功耗优化

针对高性能通用处理器的结构特性及设计特点,指出了由于在高性能通用处理器中存在发射宽度较大、数据通路规整的基本特点,其大多数电路中的堆叠效应依然明显存在．由此结合一款高性能通用处理器——龙芯2号的具体设计,对该处理器主要数据通路模块进行了输入向量控制,并提出以“直接观察法”、“有效分解法”、“操作数隔离复用法”、“模拟退火算法”等多种技术思想为基础的电路最小漏电功耗分析及优化的实用性方法．实验结果表明,以上方案能够使得处理器的主要数据通路的漏电功耗减少近27％,同时模拟退火算法与以往的随机算法以及遗传算法相比在寻找电路最小漏电功耗的全局搜索能力上具有优势．     

轻型单体液压支柱与前探梁临时支护对比效果分析

对新生煤矿100105工作面两顺槽使用前探梁临时支护与玻璃钢材料的轻型单体液压支柱作为临时支护的效果进行了分析.经实践可得,轻型单体液压支柱质量轻、操作方便,相比使用前探梁支护大大降低了工人的劳动强度,提高了工作效率,保障了安全性.     

Dipotassium Glycyrrhizinate on Melanoma Cell Line: Inhibition of Cerebral Metastases Formation by Targeting NF-kB Genes-Mediating MicroRNA-4443 and MicroRNA-3620—Dipotassium Glycyrrhizinate Effect on Melanoma

Glycyrrhizic acid (GA), a natural compound isolated from licorice (Glycyrrhiza glabra), has exhibited anti-inflammatory and anti-tumor effects in vitro. Dipotassium glycyrrhizinate (DPG), a dipotassium salt of GA, also has shown an anti-tumor effect on glioblastoma cell lines, U87MG and T98G. The study investigated the DPG effects in the melanoma cell line (SK-MEL-28). MTT assay demonstrated that the viability of the cells was significantly decreased in a time- and dose-dependent manner after DPG (IC₅₀ = 36 mM; 24 h). DNA fragmentation suggested that DPG (IC₅₀) induced cellular apoptosis, which was confirmed by a significant number of TUNEL-positive cells (p-value = 0.048) and by PARP-1 [0.55 vs. 1.02 arbitrary units (AUs), p-value = 0.001], BAX (1.91 vs. 1.05 AUs, p-value = 0.09), and BCL-2 (0.51 vs. 1.07 AUs, p-value = 0.0018) mRNA compared to control cells. The proliferation and wound-healing assays showed an anti-proliferative effect on DPG-IC₅₀-treated cells, also indicating an inhibitory effect on cell migration (p-values < 0.001). Moreover, it was observed that DPG promoted a 100% reduction in melanospheres formation (p-value = 0.008). Our previous microRNAs (miRs) global analysis has revealed that DPG might increase miR-4443 and miR-3620 expression levels. Thus, qPCR showed that after DPG treatment, SK-MEL-28 cells presented significantly high miR-4443 (1.77 vs. 1.04 AUs, p-value = 0.02) and miR-3620 (2.30 vs. 1.00 AUs, p-value = 0.01) expression compared to control cells, which are predicted to target the NF-kB, CD209 and TNC genes, respectively. Both genes are responsible for cell attachment and migration, and qPCR revealed significantly decreased CD209 (1.01 vs. 0.54 AUs, p-value = 0.018) and TNC (1.00 vs. 0.31 AUs, p-value = 2.38 × 10⁻⁶) mRNA expression levels after DPG compared to untreated cells. Furthermore, the migration of SK-MEL-28 cells stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA) was attenuated by adding DPG by wound-healing assay (48 h: p-value = 0.004; 72 h: p-value = 7.0 × 10⁻⁴). In addition, the MMP-9 expression level was inhibited by DPG in melanoma cells stimulated by TPA and compared to TPA-treated cells (3.56 vs. 0.99 AUs, p-value = 0.0016) after 24 h of treatment. Our results suggested that DPG has an apoptotic, anti-proliferative, and anti-migratory effect on SK-MEL-28 cells. DPG was also able to inhibit cancer stem-like cells that may cause cerebral tumor formation.     

含大剂量功能性油剂的热塑性聚合物母粒SROPE

SROPE技术是用加入第三组分嵌段聚合物的方法使大剂量的功能性油剂混入热塑性聚合物中,制成具有油剂缓慢析出性能的母粒,可赋予聚合物一定的功能性。SROPE技术对于几乎所有的模压和熔融纺丝工艺都有相当广泛的通用性。