Electronic structure and optical properties of F-doped β-Ga2O3 from first principles calculations

The effects of F-doping concentration on geometric structure, electronic structure and optical property of β-Ga₂O₃ were investigated. All F-doped β-Ga₂O₃ with different concentrations are easy to be formed under Ga-rich conditions, the stability and lattice parameters increase with the F-doping concentration. F-doped β-Ga₂O₃ materials display characteristics of the n-type semiconductor, occupied states contributed from Ga 4s, Ga 4p and O 2p states in the conduction band increase with an increase in F-doping concentration. The increase of F concentration leads to the narrowing of the band gap and the broadening of the occupied states. F-doped β-Ga₂O₃ exhibits the sharp band edge absorption and a broad absorption band. Absorption edges are blue-shifted, and the intensity of broad band absorption has been enhanced with respect to the fluorine content. The broad band absorption is ascribed to the intra-band transitions from occupied states to empty states in the conduction band.     

A MXene-derived redox homeostasis regulator perturbs the Nrf2 antioxidant program for reinforced sonodynamic therapy

Ultrasound (US)-mediated sonodynamic therapy (SDT) has emerged as a spatiotemporally controllable therapeutic modality in combating cancer because of its high tissue-penetration depth and minimal invasiveness. However, the elevated nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant program in cancer cells can serve as a chief reactive oxygen species (ROS) detoxification system to alleviate oxidative injury and promote tumorigenesis, and thus greatly antagonize the therapeutic efficacy of ROS-mediated anticancer therapies. Herein, we report that vanadium carbide MXene-derived carbon dots (PMQDs) can act as high-efficacy sonosensitizers to efficiently generate ROS upon US irradiation and simultaneously hinder the Nrf2 antioxidant program for enhanced sonodynamic therapy of cancer. These PMQDs show superior US-triggered ROS generating ability because of their efficient migration/separation of electron–hole pairs and narrow bandgap. Importantly, these PMQDs can serve as efficient redox homeostasis regulators to perturb the Nrf2 antioxidant mechanism and thus reduce its effects on ROS neutralization for enhanced SDT efficacy. Overall, the present study will not only provide a new paradigm to augment SDT by perturbing the Nrf2 antioxidant program, but also give valuable insights into developing high-efficacy MXene-derived nanoagents for cancer therapy.

A redox homeostasis regulator has been developed as a high-efficacy sonosensitizer to efficiently generate reactive oxygen species upon ultrasound irradiation and simultaneously hinder the Nrf2 antioxidant program for enhanced sonodynamic therapy.     

Mesoporous sodium four-coordinate aluminosilicate nanoparticles modulate dendritic cell pyroptosis and activate innate and adaptive immunity

Pyroptosis is a programmed cell death widely studied in cancer cells for tumour inhibition, but rarely in dendritic cell (DC) activation for vaccine development. Here, we report the synthesis of sodium stabilized mesoporous aluminosilicate nanoparticles as DC pyroptosis modulators and antigen carriers. By surface modification of sodium-stabilized four-coordinate aluminium species on dendritic mesoporous silica nanoparticles, the resultant Na-^IVAl-DMSN significantly activated DC through caspase-1 dependent pyroptosis via pH responsive intracellular ion exchange. The released proinflammatory cellular contents further mediated DC hyperactivation with prolonged cytokine release. In vivo studies showed that Na-^IVAl-DMSN induced enhanced cellular immunity mediated by natural killer (NK) cells, cytotoxic T cells, and memory T cells as well as humoral immune response. Our results provide a new principle for the design of next-generation nanoadjuvants for vaccine applications.

Na-^IVAl-DMSN acts as both antigen carriers and modulators to “hyperactivate” dendritic cells (DCs) via potassium (K⁺) efflux dependent pyroptosis, eventually leading to enhanced adaptive and innate immunity.     

Precise electro-reduction of alkyl halides for radical defluorinative alkylation

Reported here is a precise electro-reduction strategy for radical defluorinative alkylation towards the synthesis of gem-difluoroalkenes from α-trifluoromethylstyrenes. According to the redox-potential difference of the radical precursors, direct or indirect electrolysis is respectively adopted to realize the precise reduction. An easy-to-handle, catalyst-and metal-free condition is developed for the reduction of alkyl radical precursors that are generally easier to be reduced than α-trifluorome...     

荧光寿命成像显微技术

介绍荧光寿命成像显微（FLIM）技术及其在生物物理、生物化学及临床医学诊断等领域的最新研究成果和发展现状，并就其未来的发展及应用研究进行了讨论。     

基于模糊空间非标准划分的模糊神经控制

提出一种基于模糊空间非标准划分的模糊神经控制方法。该方法克服了基于模糊空间标准划分 (网格状划分 )的模糊子空间急剧增加(指数增长 )的弊病 ,减少了计算负担。并通过对倒立摆控制的仿真研究说明了所提方法的有效性     

小型化火花预电离TEA CO2激光器的实验研究

介绍了一种小型化火花预电离高能输出横向激励大气压(TEA)CO2激光器.激光器的主放电电极采取紧凑式Ernst电极,加大了电极间距,增大了激活区体积,从而提高了输出能量.激光器采用火花阵列预电离方式,有利于主放电均匀、稳定.低重复频率下,自由振荡情况下的输出能量可达到2 J.使用单片机控制的光栅调谐后,10P(20)谱线多模输出能量可达到1J,10 P(20)谱线输出脉冲宽度为100 ns.     

单相电压源变换器减少开关次数调制算法的研究

作为基本的电力电子变换器,单相全桥结构两电平电压源变换器包括单相电压源逆变器、单相并网逆变器、单相电压源整流器和单相有源电力滤波器,具有广泛的应用场合。鉴于单相电压源变换器具有多解性,可以寻找一种减少开关次数的调制算法,以便降低开关损耗。本文根据三相电压源全桥结构两电平电压源变换器的最小开关次数调制算法,设计了一种适合单相全桥结构两电平电压源变换器的最少开关次数的调制算法,在理论分析的基础上,采用MATLAB/SIMULINK进行了仿真验证。     

大幅面高光谱扫描系统在文物研究中的应用

为使高光谱成像技术能够在大幅面绘画类文物研究和保护中充分发挥面分析的优势,研制了大幅面高光谱扫描系统,同时建立了传统颜料数据库。与以往高光谱成像技术对文物进行的局部分析相比,该系统不仅提高了分析效率,而且可对绘画文物整体进行颜料鉴别和相对浓度分布研究,可以为绘画中复杂调色工艺的研究提供巨大的帮助。目前,已使用该系统对故宫博物院东华门天花彩画、纸本书画《丁观鹏画不二尊者图轴》、绢本书画《沈庆兰画贴落》和唐卡《吉祥天母画佛像》进行分析研究,并将其用于文物隐藏病害、隐藏墨迹、底稿线等信息的提取与增强,颜料成分鉴别和混合颜料工艺研究等方面,取得了良好的效果,对绘画类文物的研究与保护具有重要的意义。     

微机械可调谐垂直腔面发射激光器调谐范围分析与设计

介绍了可调谐激光器的意义和它的基本调谐方法及调谐原理.对影响微机械可调谐垂直腔面发射激光器调谐范围的因素做了重点分析,计算了空气隙的最大变化范围和由此引起的激射波长的调谐范围.