Highly conductive dodecaborate/MXene composites for high performance supercapacitors

With the increasingly prominent energy and environmental issues, the supercapacitors, as a highly efficient and clean energy conversion and storage devices, meet the requirements well. However, it is still a challenge to enhance the capacitance and energy density of supercapacitors. A novel and highly conductive dodecaborate/MXene composites have been designed for high performance supercapacitors. The surface charge property of MXene was modified by a simple ultrasonic treatment with ammonium ion, and the dodecaborate ion can be inserted into the inner surface of MXene by electrostatic adsorption. Due to the unique icosahedral cage conjugate structure formed by the B-B bond and the highly delocalized three-dimensional π bond structure of the electrons, the negative charge is delocalied on the whole dodecaborate ion, which reduces the ability to bind to cations. Therefore, the cations can move easily, and the dodecaborate can act as a “lubricant” for ion diffusion between the MXene layers, which significantly improves the ion transfer rate of supercapacitors. The dodecaborate/MXene composites can achieve an extremely high specific capacitance of 366 F.g^-1 at a scan rate of 2 mV.s^-1, which is more than eight times higher than that of MXene (43 F^1-) at the same scan rate. Our finding provides a novel route on the fabrication of the high performance supercapacitors.

     

浙江示范型居家养老服务中心建设的最新进展——来自杭州市主城区的调查报告

在"十三五"国家老龄事业发展和养老体系建设规划的指引下,示范型居家养老服务中心建设在浙江省全面展开.文章选取杭州主城区三个有代表性的区域,对其中全部18家示范型居家养老服务中心进行了使用后评价普查.通过对设施布点、硬件设施、服务内容、使用状况及户外环境的调查与分析,为改进和完善城市社区养老设施建设提出了相关建议.     

RB Regulates DNA Double Strand Break Repair Pathway Choice by Mediating CtIP Dependent End Resection

Inactivation of the retinoblastoma tumor suppressor gene (RB1) leads to genome instability, and can be detected in retinoblastoma and other cancers. One damaging effect is causing DNA double strand breaks (DSB), which, however, can be repaired by homologous recombination (HR), classical non-homologous end joining (C-NHEJ), and micro-homology mediated end joining (MMEJ). We aimed to study the mechanistic roles of RB in regulating multiple DSB repair pathways. Here we show that HR and C-NHEJ are decreased, but MMEJ is elevated in RB-depleted cells. After inducing DSB by camptothecin, RB co-localizes with CtIP, which regulates DSB end resection. RB depletion leads to less RPA and native BrdU foci, which implies less end resection. In RB-depleted cells, less CtIP foci, and a lack of phosphorylation on CtIP Thr847, are observed. According to the synthetic lethality principle, based on the altered DSB repair pathway choice, after inducing DSBs by camptothecin, RB depleted cells are more sensitive to co-treatment with camptothecin and MMEJ blocker poly-ADP ribose polymerase 1 (PARP1) inhibitor. We propose a model whereby RB can regulate DSB repair pathway choice by mediating the CtIP dependent DNA end resection. The use of PARP1 inhibitor could potentially improve treatment outcomes for RB-deficient cancers.     

6061铝合金均匀化过程中AlMnSi弥散颗粒的析出尺寸对再结晶行为的影响

利用力学性能测试、光学显微镜、扫描电镜、透射电镜和能谱分析技术等手段研究了均匀化过程中AlMnSi弥散颗粒的析出尺寸对6061铝合金再结晶行为的影响。结果表明:AlMnSi弥散颗粒在均匀化过程中沿着铝基体[001]晶带轴析出长大,晶体结构为体心立方结构。随着均匀化温度的升高,弥散颗粒的析出尺寸逐渐增大,当AlMnSi弥散颗粒平均尺寸由0.07 μm增长到0.42 μm,最大尺寸由0.21 μm增大到1.12 μm时,力学性能则是先升高后降低。6061铝合金T6态组织仍为变形组织;AlMnSi弥散颗粒尺寸增大到1.12 μm,6061合金T6态组织中出现粗大再结晶,力学性能急剧降低。     

Dispersion in steady and time-oscillatory flows through an eccentric annulus

A multiple-scale perturbation is conducted to derive an averaged equation for predicting the longtime solute transport in an eccentric annulus in which the uniaxial flow may oscillate periodically in time. A proof for the positiveness of the dispersivity is presented, implying that over a cycle of oscillation a solute cloud always broadens. For a steady flow driven by a fixed pressure gradient, increasing the eccentricity and annulus size gives rise to stronger dispersion. This relationship holds when the flow becomes unsteady. In the limit of slow oscillation, dispersion due to an oscillatory flow asymptotes to one-half of that by a steady flow. Increasing the oscillation frequency leads to a two-step decay of the dispersivity. The maximum dispersion in an oscillatory flow can be achieved in the limit of slow oscillation and large eccentricity, where dispersion can be O(10³) times larger than that in an otherwise concentric annulus.