Preparation of Silica Aerogel/Resin Composites and Their Application in Dental Restorative Materials

As the most advanced aerogel material, silica aerogel has had transformative industrial impacts. However, the use of silica aerogel is currently limited to the field of thermal insulation materials, so it is urgent to expand its application into other fields. In this work, silica aerogel/resin composites were successfully prepared by combining silica aerogel with a resin matrix for dental restoration. The applications of this material in the field of dental restoration, as well as its performance, are discussed in depth. It was demonstrated that, when the ratio of the resin matrix Bis-GMA to TEGDMA was 1:1, and the content of silica aerogel with 50 μm particle size was 12.5%, the composite achieved excellent mechanical properties. The flexural strength of the silica aerogel/resin composite reached 62.9546 MPa, which was more than five times that of the pure resin. Due to the presence of the silica aerogel, the composite also demonstrated outstanding antibacterial capabilities, meeting the demand for antimicrobial properties in dental materials. This work successfully investigated the prospect of using commercially available silica aerogels in dental restorative materials; we provide an easy method for using silica aerogels as dental restorative materials, as well as a reference for their application in the field of biomedical materials.     

Pogostone Enhances the Antibacterial Activity of Colistin against MCR-1-Positive Bacteria by Inhibiting the Biological Function of MCR-1

The emergence of the plasmid-mediated colistin resistance gene mcr-1 has resulted in the loss of available treatments for certain severe infections. Here we identified a potential inhibitor of MCR-1 for the treatment of infections caused by MCR-1-positive drug-resistant bacteria, especially MCR-1-positive carbapenem-resistant Enterobacteriaceae (CRE). A checkerboard minimum inhibitory concentration (MIC) test, a killing curve test, a growth curve test, bacterial live/dead assays, scanning electron microscope (SEM) analysis, cytotoxicity tests, molecular dynamics simulation analysis, and animal studies were used to confirm the in vivo/in vitro synergistic effects of pogostone and colistin. The results showed that pogostone could restore the bactericidal activity of colistin against all tested MCR-1-positive bacterial strains or MCR-1 mutant–positive bacterial strains (FIC < 0.5). Pogostone does not inhibit the expression of MCR-1. Rather, it inhibits the binding of MCR-1 to substrates by binding to amino acids in the active region of MCR-1, thus inhibiting the biological activity of MCR-1 and its mutants (such as MCR-3). An in vivo mouse systemic infection model, pogostone in combination with colistin resulted in 80.0% (the survival rates after monotherapy with colistin or pogostone alone were 33.3% and 40.0%) survival at 72 h after infection of MCR-1-positve Escherichia coli (E. coli) ZJ487 (blaNDM-1-carrying), and pogostone in combination with colistin led to one or more order of magnitude decreases in the bacterial burdens in the liver, spleen and kidney compared with pogostone or colistin alone. Our results confirm that pogostone is a potential inhibitor of MCR-1 for use in combination with polymyxin for the treatment of severe infections caused by MCR-1-positive Enterobacteriaceae.     

Approach for the Direct Synthesis of β-Dichlorosubstituted Acetanilides Using Iodine Trichloride (ICl3) as the Oxidant and Catalyst

A reliable method for direct synthesis of β‐dichlorosubstituted acetanilides is reported. The key transformation involves the oxidative and catalytic cleavage of a carbon‐carbon bond in the presence of iodine trichloride (ICl₃). In this protocol ICl₃ is used not only as the catalyst but also as the oxidant which widely broadens the scope of its application in organic synthetic chemistry.     

Coral reef-like polyanaline nanotubes prepared by a reactive template of manganese oxide for supercapacitor electrode

Coral reef-like PANI nanotubes composed of nanopaticles were successfully synthesized by a reactive template of manganese oxide.The structure was characterized by using SEM,TEM,and FT-IR,and the supercapacitive behaviors of these nanotubes were investigated with cyclic voltammetry（CV）,and charge-discharge tests,respectively.A maximum specific capacitance of 533 F/g could be achieved in 1mol/L aqueous H₂SO₄ with the potential range of -0.2 to 0.8 V（vs.the saturated calomel electrode） in a half-cell setup configuration for PANI electrode,suggesting its potential application in the electrode material for electrochemical capacitors.     

冲击波温度和压力对二氧化钛相变的影响

 介绍了一种简便易行的降低疏松固体物质冲击波温度的方法，其要点是用液体石蜡充填样品的空隙。以用粉末锐钛矿压装成型的样品为例，对比了不充填和充填液态石蜡时冲击波作用的结果。在同样的冲击加载条件下（均为钢飞片，撞击速度为3.16 km/s），估算两种样品中达到的压力分别为36.3 GPa和46.8 GPa，平均温度分别约为4.7×10³ ℃和2.0×10³ ℃，即：充填液态石蜡的样品中压力增加了约10 GPa，但平均温度降低了近3×10³ ℃。对冲击后回收样品的分析结果表明，不充填石蜡样品的主要产物为金红石，即冲击波产生的高温起了主要作用。而充填液态石蜡时，主要生成β-TiO₂高压相，即高压起了主要作用。     

利用X射线衍射研究冲击波合成纤锌矿型氮化硼

 用X射线衍射法，对不同结晶度的石墨型氮化硼（gBN）在冲击波作用下转变成的纤锌矿型氮化硼（wBN）产物进行了研究，对wBN中的杂质含量等进行了分析。结果表明：gBN的石墨化指数G.I值对wBN的产率有明显的影响。     

酸性红黄壤土上大麦遗传改良研究

本文报道了酸性红黄壤土上大麦遗传改良研究结果:(1)采用酸铝营养液培养幼苗的方法鉴定了我国3871份大麦品种的耐酸铝性，得到一级耐性材料315份，占鉴定总数的8.13劣，(2)相关通径分析表明，酸性红黄壤土上大麦单株籽粒产量损失起主要作用的是有效分菜数下降(P = 0. 7324 )、每穗实粒数减少(P = 0 . 5923 )和千粒重降低(P = 0.5877),由此可见，这是在红黄壤土田间条件下选择耐酸铝性大麦的三个主要选择指标;(3)发现大麦耐酸铝性基因遗传方式除单基因遗传方式外，尚有多基因控制的表现数量性状遗传方式;'(4)从对酸铝性表现敏感的大麦品种“早熟3一号”的花药、幼胚等外植体诱导出的愈伤组织，通过离体细胞突变体筛选，得到了“耐性细胞系”.以上结果表明，通过耐酸铝性遗传改良培育出适应酸性红黄壤土种植的大麦新品种是可行的，亦为开发利用红黄壤土地资源补充了另一条有效途径.     

催化光度法测定痕量铁

基于铁对过氧化氢氧化对-氨基二甲基苯胺盐酸盐的催化活性,建立了测定痕量的新方法。灵敏度为1.6×10-11g/mL,测定范围为0～0.50μg Fe/50mL,用于测定几种实物样品中的痕量铁,相对标准偏差0.65～2.6%.