Premature Termination Codon in 5′ Region of Desmoplakin and Plakoglobin Genes May Escape Nonsense-Mediated Decay through the Reinitiation of Translation

Arrhythmogenic cardiomyopathy is a heritable heart disease associated with desmosomal mutations, especially premature termination codon (PTC) variants. It is known that PTC triggers the nonsense-mediated decay (NMD) mechanism. It is also accepted that PTC in the last exon escapes NMD; however, the mechanisms involving NMD escaping in 5′-PTC, such as reinitiation of translation, are less known. The main objective of the present study is to evaluate the likelihood that desmosomal genes carrying 5′-PTC will trigger reinitiation. HL1 cell lines were edited by CRISPR/Cas9 to generate isogenic clones carrying 5′-PTC for each of the five desmosomal genes. The genomic context of the ATG in-frame in the 5′ region of desmosomal genes was evaluated by in silico predictions. The expression levels of the edited genes were assessed by Western blot and real-time PCR. Our results indicate that the 5′-PTC in PKP2, DSG2 and DSC2 acts as a null allele with no expression, whereas in the DSP and JUP gene, N-truncated protein is expressed. In concordance with this, the genomic context of the 5′-region of DSP and JUP presents an ATG in-frame with an optimal context for the reinitiation of translation. Thus, 5′-PTC triggers NMD in the PKP2, DSG2* and DSC2 genes, whereas it may escape NMD through the reinitiation of the translation in DSP and JUP genes, with no major effects on ACM-related gene expression.     

电机保护装置设计中几个问题的探讨

给出了一种实现双CPU分体式结构的接口电路.此外,笔者还就电机保护的延时时间系统和散热过程的模拟实现进行了探讨.实验表明,所设计的接口电路能实现显示模块的热插拔,基于单一定时计数器的延时时间系统和通过变时间步长查表方式实现的散热过程简单易行,有着较好的精度.     

真空封装硅微陀螺品质因数的标定

建立了真空封装陀螺的无激励欠阻尼二阶系统模型,用于测量真空封装硅微陀螺的品质因数。对该模型进行理论推导,提出了一种时延常数测试方法。该方法首先利用锁相环路,驱动陀螺实现闭环谐振,获得较大的初始振幅。然后关断激励信号,通过放大电路和解调电路,记录硅微陀螺振荡幅值的衰减过程;用计算机通过Matlab GUI实时采集并拟合振幅衰减曲线,获得时间常数。最后,通过时间常数解算获得真空封装硅微陀螺的品质因数。对真空封装硅微陀螺品质因数的实验测试结果表明:该方法实测数据与理论分析模型的拟合度为99.999%,测试重复性为4.03%,优于传统的扫频测试法的重复性。对比时延常数法与锁相放大器扫频测试法的测试数据显示:时延常数法具有更高的测量精度和更高的测试效率。该方法可以推广到其它高真空封装MEMS器件的品质因数测量。     

Polymer interface changes in electrophoretic deposition

A Monte Carlo computer simulation model for the electrophoretic deposition of polymer chains on a discrete lattice is used to study the polymer density profile, interface growth, and its dependence on field, temperature, and molecular weight. The interface width (W) decreases WE^−1/2 on increasing the field (E). Width (W) depends non-monotonically on the temperature (T): a power-law decay is followed by a power-law increase on raising the temperature. Monotonic decay of the interface width with the molecular weight is possibly a stretched exponential. Conformation and dynamics of a tracer chain is used to probe its characteristics in interface to bulk region. The root mean square (rms) displacement of the center of mass of the tracer chain shows an ultra-slow motion, Rt^ν (ν0.1–0.01 at E=0.1–1.0) as the driven chain moves deeper from interface to bulk. Longitudinal compression of the radius of gyration (R_g) of the chain increases with the field; transverse components (R_gx, R_gy) are larger than the longitudinal component (R_gz). The transverse component (R_gx(y)) becomes oscillatory due to periodic squeezing at high fields as the field competes with the polymer barriers.     

致密破碎多孔介质渗透率测量方法

基于均匀各向同性多孔介质、达西渗流和理想气体假设,考虑Klinkenberg效应建立了针对具有纳米尺度孔径的低渗透率多孔介质中的渗流模型。针对致密球形破碎样品的压力脉冲实验,建立了相应的边界条件,同时利用有限差分方法获得其实验腔的压力变化曲线的数值解。通过对渗流方程进行量纲1化,引入了与孔隙率、渗透率和滑移参数有关的量纲1参数Z、Z^*和b_K。通过改变参数Z、Z^*和b_K研究了样品边界处压力的变化规律,给出了一种数据处理方法,对于致密球形破碎多孔介质的压力脉冲实验,通过对实验测量的样品边界处压力曲线的分析,结合偏微分方程正问题的数值解,可以确定样品的孔隙率、渗透率和滑移参数,从而更为简便地分析压力脉冲衰减曲线实验数据,得到致密多孔介质样品渗透率。     

高镍三元正极材料镍钴铝的掺杂改性研究进展

高镍三元正极材料镍钴铝（NCA）因具有较高的能量密度及工作电压、成本低、环境友好等优点极有可能成为下一代广泛应用的锂离子电池正极材料之一。然而镍含量的提高导致材料结构不稳定、循环性能和倍率性能降低,限制了其进一步发展。主要从锂位、过渡金属位、氧位掺杂及复合共掺杂4个方面综述了不同位置离子掺杂的改性机理。大量研究结果表明,通过复合共掺杂方式进行改性,能够结合单离子掺杂的优点有效提升镍钴铝正极材料的电化学性能。     

气液螺旋环状流压降特性研究

考虑旋流衰减的影响,对气液螺旋环状流的压降特性进行研究并推导出了螺旋环状流压降预测模型。定义压降旋-直比系数为气液两相螺旋环状流和气液两相直流的压降之比,以此来表征旋流衰减对压降的影响。基于量纲分析的方法对压降旋-直比系数进行分析,推导出其表达式,压降旋-直比系数依赖于Lockhart-Martinelli 参数和气相Froude数变化。最终,得出了气液两相螺旋环状流的压降预测模型。在50 mm内径的水平管内对螺旋环状流的压降特性进行了实验研究,其中气相表观流速变化范围为10~16 m/s,体积含液率（LVF）变化范围为0.6%~4.8%。通过与实验数据进行对比,压降预测模型的相对误差在±15%以内,为工程应用提供了参考。     

水平油气两相流中液滴分布的衰减系数

引　言在石油、天然气的开发过程中 ,在通常的操作条件下 ,水平管线中的两相分离流 (指分层流和环状流 )是常见的流动结构 在较高的气相流速时 ,液滴可从液膜表面上被撕破而进入到中心气核中去 .液滴和其携带流体间的相互作用和相间滑移的存在强烈地影响着流动时的压降特性 ,而液滴浓度在管截面上的不均匀分布 ,也影响气相速度的分布以及对相份额的准确计算和测量 .众所周知 ,管路的压降和相份额数据是两相或多相流输送管线和管路终端处理设备的设计及安全、经济运行的最重要依据 .由此可见 ,在两相输送过程中对液滴传输特性研究的重要性 .…     

Opto-electronic high-frequency cross-correlation using avalanche photodiodes

Correlation analysis has become an important research tool in the investigation of signals and systems behaviour. We report on a special opto-electronic cross-correlator in which a silicon avalanche photodiode is used as the main component. The internal gain of this photodiode is pulse-modulated with 330 ps FWHM at 126 MHz repetition rate, or is modulated sinusoidally at frequencies of up to 882 MHz, respectively. In the pulsed mode, very weak repetitive optical pulses can be detected with 3 × 10⁻³ photons per pulse sensitivity, and with 10 ps timing accuracy. The second mode offers time-selective signal rejection capabilities with 3 ps time resolution. The opto-electronic cross-correlator can be used in displacement and distance measurement, robotics, time dispersion analysis in optical fibres, transient absorption spectroscopy, fluorescence decay measurement, lifetime-selective fluorescence detection, and in fluorescence signal suppression in Raman spectroscopy.     

Prevention of steel corrosion in concrete exposed to seawater with submerged sacrificial anodes

This paper presents the results of a study of the effectiveness of submerged sacrificial anodes in preventing the onset of pitting corrosion in the emerged part of marine piles. Experimental tests were carried out on reinforced concrete columns with steel embedded both in chloride free concrete and chloride contaminated concrete in order to compare the effects of sacrificial anodes on passive steel and on corroding steel. Results have shown, at least under the present testing conditions, that sacrificial anodes may be more effective in preventing corrosion initiation (i.e. in providing cathodic prevention) than in controlling ongoing pitting corrosion (i.e. in guaranteeing cathodic protection). Monitoring criteria for this type of prevention are also discussed.