耳蜗力学研究进展

耳蜗力学是听觉科学和生理声学研究的核心话题,同时也是一个极具代表性的生物力学话题. 深入总结和揭示耳蜗力学特性能够推动相关问题的深入研究和促进心理声学的发展与应用. 该文分宏观力学和微观力学两部分进行综述,然后结合近几年的研究动态,总结耳蜗力学的发展趋势和应用前景. 表明耳蜗作为一个杰出的频率选择和高灵敏度的声信号感应器官,可以对20~20 000 Hz 这样跨度达千倍的频率做出精确响应,且刺激信号可以放大4 000 倍以上.     

基于嵌入式平台的猫眼效应目标实时探测系统研究

在安保工作中,为快速发现狙击手,构建了利用狙击镜的猫眼效应原理来发现目标的系统。该系统不同于传统的采用连续激光扫描视场,而采用可调制半导体激光器为探测光源,在调制信号的控制下照射视场,CCD接收相应的主被动回波图像。并根据目标距离不同所成图像特征不同的特点,提出了分别针对远近目标的识别算法,最终在嵌入式DSP高速处理平台上进行图像处理实现。外场实验结果表明,主被动图像相结合,且利用远近目标不同的识别算法,有效提高了探测率,降低了虚警率,系统准确探测到了300 m近目标和800 m远目标,并达到10 frames/s的实时处理速度。     

Infrared Responsive Choline Phosphate Lipids for Synergistic Cancer Therapy

Choline phosphate lipids have been designed and developed as new-generation zwitterionic nanocarriers with excellent biocompatibility and bioorthogonality to provide a more programmable performance for cancer therapy. However, there is a lack of spatiotemporal and reversible control for drug release at target tumor cells, which can lead to severe adverse effects to normal tissue and discounted treatment outcome. Here, light-inducible Lip-cRGDfk/ICG/Dox liposomes were developed for synergistic cancer therapy. ICG can effectively convert light energy into selective heating in a local environment upon laser irradiation, thus inducing thermal ablation of tumor cells, and further reversibly trigger the spatiotemporal release of anticancer drugs (Dox) at tumor cells due to the conformation transformation of CP lipids to synergistically kill tumor cells. That Lip-cRGDfk/ICG/Dox exhibited a significant improvement for breast cancer therapy in vitro and in vivo is also demonstrated, thus it can serve as an efficient platform to noninvasively and spatiotemporally control the activation of cytotoxicity at tumor cells for precision cancer therapy.     

Multi-Step Continuous-Flow Organic Synthesis: Opportunities and Challenges

Continuous-flow multi-step synthesis takes the advantages of microchannel flow chemistry and may transform the conventional multi-step organic synthesis by using integrated synthetic systems. To realize the goal, however, innovative chemical methods and techniques are urgently required to meet the significant remaining challenges. In the past few years, by using green reactions, telescoped chemical design, and/or novel in-line separation techniques, major and rapid advancement has been made in this direction. This minireview summarizes the most recent reports (2017–2020) on continuous-flow synthesis of functional molecules. Notably, several complex active pharmaceutical ingredients (APIs) have been prepared by the continuous-flow approach. Key technologies to the successes and remaining challenges are discussed. These results exemplified the feasibility of using modern continuous-flow chemistry for complex synthetic targets, and bode well for the future development of integrated, automated artificial synthetic systems.     

对数似然图像分割的快速主动轮廓跟踪算法

针对跟踪目标尺度变化问题,提出了基于灰度对数似然图像分割的快速主动轮廓跟踪算法。改进的主动轮廓跟踪算法将根据以目标与背景的颜色差异而建立的对数似然图对图像进行阈值分割和数学形态学处理,再将Kalman滤波器结合到主动轮廓跟踪算法进行目标跟踪。改进的主动轮廓跟踪算法对目标分割准确,轮廓特征显著,跟踪效果稳定,算法能很好地适应跟踪目标尺度变化。通过Kalman滤波器对目标位置点的预测减少了主动轮廓跟踪算法收敛的迭代次数,使算法的运算效率提高了33%左右。     

用于BB84相位编码量子密钥分发系统的不间断式主动相位补偿方案

提出一种新的不间断的主动相位补偿方案,在进行量子密钥分发的同时统计不匹配基量子比特在干涉仪不同输出端口上的随机计数分布,给出了由不匹配基量子比特统计数值计算相位漂移参数的计算公式,并由统计数值计算得到相位漂移参数。结果表明：该方案允许系统并行处理量子密钥分发与相位补偿,也充分利用了在原BB84协议中会被丢弃的不匹配基量子比特信息。     

铁-钼/活性炭催化剂的费-托合成反应性能

用微型固定床反应器和原位穆斯堡尔谱考察了在活性炭担载的铁-钼双金属催化剂上的费-托合成反应和在反应条件下的物相。已知在费-托合成中铁有利于生成长链烃,钼有利于生成低碳烃。铁-钼/活性炭催化剂则综合了铁和钼的性质,其中铁-钼/油棕炭催化剂具有很好的活性和液化石油气选择性。在反应中,富钼催化剂的主要物相为铁-钼碳化物,而富铁催化剂的物相则为铁-钼碳化物和e’-Fe_2·2C碳化铁。     

KIT-6负载CeO2催化CO2和甲醇合成碳酸二甲酯

采用不同老化温度(80、100、120和150℃)合成了一系列KIT-6载体,并通过浸渍法制备了相应的CeO_2/KIT-6催化剂。结合X射线衍射、N_2物理吸附、NH_3程序升温脱附、CO_2程序升温脱附、透射电子显微镜、傅里叶变换红外光谱和X射线光电子能谱等表征结果,详细考察了老化温度对KIT-6结构以及CeO_2/KIT-6催化剂直接催化CO_2和甲醇合成碳酸二甲酯(DMC)反应活性的影响。结果表明,不同老化温度下制备的KIT-6均保持其独特的三维孔道结构。随着老化温度升高,KIT-6比表面积先增大后减小,当老化温度为100℃时,KIT-6比表面积达到最大(683 m~2·g~(-1))。KIT-6较高的比表面积有利于提高CeO_2分散度,进而提高暴露的活性位点数量,催化活性随催化剂表面中等碱/酸性吸附位数量和Ce~(3+)含量的增加而逐渐提高。其中,CeO_2/100-KIT-6催化剂中CeO_2颗粒尺寸最小(5.9 nm),暴露的活性位数量最高,催化活性最佳。随后,考察了反应温度和压力对CeO_2/100-KIT-6催化活性的影响。随着反应温度提高,催化活性先升高后降低,当反应温度为140℃时,催化活性最高;且催化活性随反应压力的提高而逐渐增加。在反应温度为140℃、压力为6.8 MPa条件下,催化剂经6次循环后,DMC收率由15 mmol·g_(CeO_2)~(-1)逐渐降低至2.8 mmol·g_(CeO_2)~(-1),原因归结为反应过程中CeO_2纳米颗粒发生团聚,使暴露出的活性位数量减少。     

表皮生长因子受体酪氨酸激酶抑制剂的药效团研究

根据一系列表皮生长因子受体酪氨酸激酶抑制剂的三维定量构效关系研究，得 到了该类抑制剂的药效团，研究结果与Novartis的药效团模型相当类似．药效团包 括一个氢键受体，一个氢键给体，一个疏水区和一个带有氯或溴原子药效团对于研 究表皮生长因子受体酪氨酸激酶抑制剂结构与活性的关系具有重要的意义．通过三 维数据库搜索可能会得到新的先导化合物．     

On the choice of active space orbitals in MCSCF calculations

We describe a procedure which may be used to aid selection of the active space in multiconfigurational self-consistent field (MCSCF) calculations for general chemical systems. Starting from a restricted Hartree-Fock calculation, we define a hierarchy of interacting virtual orbitals for every occupied orbital. The most strongly interacting orbitals are then taken to constitute the active space in a configuration interaction (CI) calculation. The natural orbital occupation numbers obtained from the CI calculation are then used to choose the active space to be used in a subsequent MCSCF calculation. We illustrate our method on a number of systems (Li₂, B₂, C₂, carbonyl oxide and the transition state for oxidation of H₂S by dioxirane). In all these cases, ‘intuitive’ active spaces are inadequate, as are active spaces derived from the natural orbitals of unrestricted Hartree-Fock calculations.