Surfactant-Assisted Purification of Hydrophobic DNA Nanostructures

Purification of functional DNA nanostructures is an essential step in achieving intended functions because misfolded structures and the remaining free DNA strands in a solution can interact and affect their behavior. However, due to hydrophobicity-mediated aggregation, it is difficult to purify DNA nanostructures modified with hydrophobic molecules by conventional methods. Herein, we report the purification of cholesterol-modified DNA nanostructures by using a novel surfactant-assisted gel extraction. The addition of sodium cholate (SC) to the sample solution before structure folding prevented aggregation; this was confirmed by gel electrophoresis. We also found that adding sodium dodecyl sulfate (SDS) to the sample inhibited structural folding. The cholesterol-modified DNA nanostructures prepared with SC were successfully purified by gel extraction, and their ability to bind to the lipid membrane surfaces was maintained. This method will facilitate the purification of DNA nanostructures modified with hydrophobic molecules and expand their applicability in the construction of artificial cell-like systems.     

Giant dielectric response and grain heterogeneity of Y2/3Cu3Ti4O12–TiO2 composite ceramics fabricated by hydrothermal process

Due to the boom of the electronic information industry, dielectric ceramic materials are widely applied in passive components such as multilayer ceramic capacitors. In this article, Y_2/3Cu₃Ti₄O₁₂–TiO₂ composite ceramics with outstanding dielectric properties (ε_r = 2.29 × 10⁶ at 20 Hz, ε_r = 4.49×10⁵ at 1 kHz) were successfully prepared by hydrothermal and in situ solid-state methods. The minimum dielectric loss value (at 1 kHz) of the obtained composite ceramics is about 0.57. The experimental results show that Y_2/3Cu₃Ti₄O₁₂ has a composite perovskite structure with cation vacancies, which causes internal electron-pinned defect-dipole, and the easy entry of excessive titanium ions to produce donor defects. Meanwhile, the heterogeneous grains with a pomegranate-like microstructure were observed in the prepared composite ceramics, and interfacial polarization between subgrain boundaries was substantiated by impedance analysis. The abundant weakly trapped electrons and more polarized interfaces formed by grain and subgrain boundaries are the primary sources of the excellent dielectric properties of composite ceramics.     

隧道结巨磁电阻材料的研究进展

在概述隧道结巨磁电阻效应及其机理的基础上,综合介绍了多层薄膜结构、微颗粒膜结构和近年来出现的基于多晶隧道结结构的巨磁电阻效应及其相关材料的研究最新进展。重点讨论了涉及隧道结磁电阻材料类型、化学组成、结构与性能、制备技术以及潜在的应用前景,对制备工艺简单、成本低并可能带来突破性发展的多晶隧道结巨磁电阻材料作了展望。     

Self-Assembling Properties and Recovery Effects on Damaged Skin Cells of Chemically Synthesized Mannosylerythritol Lipids

Mannosylerythritol lipids (MELs), which are one of the representative sugar-based biosurfactants (BSs) produced by microorganisms, have attracted much attention in various fields in the sustainable development goals (SDGs) era. However, they are inseparable mixtures with respect to the chain length of the fatty acids. In this study, self-assembling properties and structure-activity relationship (SAR) studies of recovery effects on damaged skin cells using chemically synthesized MELs were investigated. It was revealed, for the first time, that synthetic and homogeneous MELs exhibited significant self-assembling properties to form droplets or giant vesicles. In addition, a small difference in the length of the fatty acid chains of the MELs significantly affected their recovery effects on the damaged skin cells. MELs with medium or longer length alkyl chains exhibited much higher recovery effects than that of C18-ceramide NP.     

八宿巨型滑坡的发现及其意义（特约稿）

巨型滑坡全球不常见,但是破坏性极强,其识别对于加深区域构造背景的认识,防灾减灾和工程建设均有指导意义。基于遥感解译、无人机地形测绘和现场调查,报道了新发现的八宿巨型滑坡及其残留堆积体特征,初步分析了成因机制与演变过程,估算了滑坡方量。主要结论如下：（1）八宿滑坡发育于怒江缝合带的夏里-八宿裂谷带内,岩性以古生界加玉桥岩群大理岩组和侏罗系马里组变质砂泥岩为主,上部岩层产状为陡倾顺坡向,下部岩层产状为陡倾逆坡向,岸坡结构总体上为上硬下软;（2）滑坡区横跨冷曲的左右两岸,长约7200m,宽约4800m,面积约22.5km2,估算方量约35×108m3,目前残余方量约14×108m3,是国内已经确认的方量最大的滑坡;（3）滑坡极可能属于历史地震诱发的高速堵江滑坡,堰塞坝高度约185m,堆积体碎裂化严重,且在冷曲右岸爬升超过600m。滑坡形成后,堆积区历经了堰塞坝溃决、多拉寺次级滑坡、泥石流堆积与冲刷、表面流水冲刷等改造过程,但是滑坡地貌特征整体保存良好。由于滑坡和泥石流堵江,冷曲在滑坡区先后两次改道;（4）从滑坡与冷曲的演变过程来看,推测滑坡的发生时间应在晚更新世。即八宿滑坡为古滑坡;（5）八宿巨型滑坡的发现说明迄今为止我们对青藏高原地质环境的认知仍然十分有限。川藏铁路等工程建设应加强基础地质与工程地质研究,以及地质灾害风险论证,确保施工与运行期安全。     

多晶La0.85Na0.17MnOz晶界间自旋相关的输运性质

实验研究了晶粒间弱连接和致密连接的La0.85Na0.17MnOz多晶样品的电磁性质,发现弱连接的样品和致密连接的样品在居里温度以下的输运性质显著不同,弱连接的样品从居里温度到77 K在低场下具有较大的磁电阻,而致密连接的样品在低温的磁电阻几乎为零.结合低温下的电阻率与外磁场的关系,可以得出,晶粒间的自旋相关的隧道效应对低温的低场磁电阻起着重要作用.     

巨磁致伸缩材料磁机械耦合系数的测量

根据磁机械耦合系数的测量原理，利用锁相放大器建立了磁机械耦合系数测量系统，并应用该系统测量了巨磁致伸缩材料的磁机械耦合系数。测试结果表明，采用锁相放大器技术所测得的磁机械耦合系数是准确可靠的。     

Giant magnetoresistance effect in Ni buffered Co/Cu/Co sandwich

The effects of Ni buffer layer on the giant magnetoresistance structure of Co/Cu/Co sandwich are investigated systematically in this paper. It is found that Ni buffer layer can induce the crystallization of the lower Ni/Co layer and produce small coercivity, thus enlarging the difference in the magnetic behavior between the two magnetic layers in the sandwich. Moreover, the use of the Ni buffer layer can also improve the interface flatness in the sandwich. All these factors enhance the sensitivity of the Ni buffered sandwich.     

巨型工程机械子午线轮胎高强度、低生热胎面基部胶配方开发

通过对国外知名品牌37.00R57和40.00R57规格巨型工程机械子午线轮胎胎面基部胶组成分析和物理性能测试,对我公司巨型工程机械子午线轮胎胎面基部胶配方进行优化设计。新开发配方半成品和成品胶料动态损耗因子分别降低37.9%和26.6%,胶料物理性能达到竞品水平,成品轮胎TKPH提升13.6%。     

Enhanced giant magnetoimpedance in heterogeneous nanobrush

ABSTRACT: A highly sensitive and large working range giant magnetoimpedance (GMI) effect is found in the novel nanostructure: nanobrush. The nanostructure is composed of a soft magnetic nanofilm and a nanowire array, respectively fabricated by RF magnetron sputtering and electrochemical deposition. The optimal GMI ratio of nanobrush is promoted to more than 250%, higher than the pure FeNi film and some sandwich structures at low frequency. The design of this structure is based on the vortex distribution of magnetic moments in thin film, and it can be induced by the exchange coupling effect between the interfaces of nanobrush.