The Effects of Charged Amino Acid Side-Chain Length on Diagonal Cross-Strand Interactions between Carboxylate- and Ammonium-Containing Residues in a β-Hairpin

The β-sheet is one of the common protein secondary structures, and the aberrant aggregation of β-sheets is implicated in various neurodegenerative diseases. Cross-strand interactions are an important determinant of β-sheet stability. Accordingly, both diagonal and lateral cross-strand interactions have been studied. Surprisingly, diagonal cross-strand ion-pairing interactions have yet to be investigated. Herein, we present a systematic study on the effects of charged amino acid side-chain length on a diagonal ion-pairing interaction between carboxylate- and ammonium-containing residues in a β-hairpin. To this end, 2D-NMR was used to investigate the conformation of the peptides. The fraction folded population and the folding free energy were derived from the chemical shift data. The fraction folded population for these peptides with potential diagonal ion pairs was mostly lower compared to the corresponding peptide with a potential lateral ion pair. The diagonal ion-pairing interaction energy was derived using double mutant cycle analysis. The Asp2-Dab9 (Asp: one methylene; Dab: two methylenes) interaction was the most stabilizing (−0.79 ± 0.14 kcal/mol), most likely representing an optimal balance between the entropic penalty to enable the ion-pairing interaction and the number of side-chain conformations that can accommodate the interaction. These results should be useful for designing β-sheet containing molecular entities for various applications.     

Canady Cold Helios Plasma Reduces Soft Tissue Sarcoma Viability by Inhibiting Proliferation,Disrupting Cell Cycle,and Inducing Apoptosis: A Preliminary Report

Soft tissue sarcomas (STS) are a rare and highly heterogeneous group of solid tumors, originating from various types of connective tissue. Complete removal of STS by surgery is challenging due to the anatomical location of the tumor, which results in tumor recurrence. Additionally, current polychemotherapeutic regimens are highly toxic with no rational survival benefit. Cold atmospheric plasma (CAP) is a novel technology that has demonstrated immense cancer therapeutic potential. Canady Cold Helios Plasma (CHCP) is a device that sprays CAP along the surgical margins to eradicate residual cancer cells after tumor resection. This preliminary study was conducted in vitro prior to in vivo testing in a humanitarian compassionate use case study and an FDA-approved phase 1 clinical trial (IDE G190165). In this study, the authors evaluate the efficacy of CHCP across multiple STS cell lines. CHCP treatment reduced the viability of four different STS cell lines (i.e., fibrosarcoma, synovial sarcoma, rhabdomyosarcoma, and liposarcoma) in a dose-dependent manner by inhibiting proliferation, disrupting cell cycle, and inducing apoptosis-like cell death.     

基于时域有限元的近场单站导体柱微波成像

介绍了一种在自由空间中对导体柱近场单站电磁成像的时域数值方法.提出以不均匀分布的点--离散点描述法,来代替通常采用的有限项三角级数逼近的形状函数来描述散射体.在正过程中采用时域有限元法获得其近区散射场,逆过程则通过遗传算法来寻找最优解.以不均匀分布于导体表面点的矢径的模作为优化变量.以在整个迭代过程中,目标散射场和计算散射场的误差总和与目标散射场场值绝对值之和的比值作为目标函数,使目标函数达到最小值来获得导体柱在自由空间中的电磁成像.     

Anisotropic Superconducting Properties of Kagome Metal CsV_3Sb_5

We systematically measure the superconducting(SC) and mixed state properties of high-quality CsV_3 Sb_5 single crystals with T_c～3.5 K.We find that the upper critical field H_(c2)(T) exhibits a large anisotropic ratio of H_(c2)~(ab)/H_(c2)~c～9 at zero temperature and fitting its temperature dependence requires a minimum two-band effective model.Moreover,the ratio of the lower critical field,H_(c1)~(ab)/H_(c1)~c,is also found to be larger than 1,which indicates that the in-plane energy dispersion is strongly renormalized near Fermi energy.Both H_(c1)(T) and SC diamagnetic signal are found to change little initially below T_c～3.5 K and then to increase abruptly upon cooling to a characteristic temperature of ～2.8 K.Furthermore,we identify a two-fold anisotropy of in-plane angular-dependent magnetoresistance in the mixed state.Interestingly,we find that,below the same characteristic T～2.8 K,the orientation of this two-fold anisotropy displays a peculiar twist by an angle of 60° characteristic of the Kagome geometry.Our results suggest an intriguing superconducting state emerging in the complex environment of Kagome lattice,which,at least,is partially driven by electron-electron correlation.     

下一代互联网真实地址寻址技术实现及试验情况

随着网络规模的不断扩大和应用方式的多样化,互联网在安全可信方面正面临着挑战.作为可信任下一代互联网的重要基础,研究真实地址寻址技术具有十分重要的意义.本文从体系结构出发,对真实地址寻址结构各个层面的技术实现进行了说明,并介绍了基于CNGI-CERNT2的真实地址寻址试验网.     

Synthesis of Halopyrazole Matrine Derivatives and Their Insecticidal and Fungicidal Activities

Matrine is a traditional botanical pesticide with a broad-spectrum biological activity that is widely applied in agriculture. Halopyrazole groups are successfully introduced to the C13 of matrine to synthesize eight new derivatives with a yield of 78–87%. The insecticidal activity results show that the introduction of halopyrazole groups can significantly improve the insecticidal activity of matrine on Plutella xylostella, Mythimna separata and Spodoptera frugiperda with a corrected mortality rate of 100%, which is 25–65% higher than matrine. The fungicidal activity results indicate that derivatives have a high inhibitory effect on Ceratobasidium cornigerum, Cibberella sanbinetti, Gibberrlla zeae and Collectot tichum gloeosporioides. Thereinto, 4-Cl-Pyr-Mat has the best result, with an inhibition rate of 23–33% higher than that of matrine. Therefore, the introduction of halogenated pyrazole groups can improve the agricultural activity of matrine.     

一种改进的折半查找算法

针对查找范围变化很大而又相对稳定的查找对象,给出了一种改进的基于区间控制的折半查找算法,当后一个查找对象在前一个查找对象附近时,在最坏状态和平均状态下,该算法与传统的标准折半查找算法相比,其查找长度显著减少,查找速度快,当父表很大而子表相对很小时,存储上仅需增加一个额外的存储单元,实现代价很小。此算法适用于过程控制中的实时查找处理,有一定的实用价值。     

反应物量对纳米晶Fe_3Al组织和性能的影响

利用铝热反应熔化方法分别在反应物量为50、100、200g的条件下制备了块体纳米晶Fe3Al材料,通过TEM和XRD研究了材料的晶粒尺寸,并研究了材料室温压缩性能和硬度。结果表明,所制备的材料主要由非晶和纳米晶组织组成,当反应物量增大,部分区域甚至出现微米晶组织。反应物量为50g时Fe3Al材料中非晶较多,不存在微米晶;反应物量为100g时主要以纳米晶为主,非晶数量减少,伴随有少量的微米晶出现;反应物量为200g时,材料以纳米晶为主,微米晶数量较100g时有所增加。随着反应物量的增加,纳米晶相的平均晶粒尺寸增加,屈服强度和硬度呈先增大后减小的趋势。     

中波红外火情遥感的大气辐射传输特性

分析2005年在广西武鸣机场进行的人工火情测量试验中获得的由BOMEM MR-154FT高光谱仪测定的火情光谱特征发现:在中波4.34～4.76μm光谱段的辐亮度比火情遥感监测常用通道3.5～4.0μm有更强的响应关系.用模拟计算方法进一步分析了中波红外光谱的大气辐射特性.分别对中波波段主要的吸收气体(水汽、水汽连续、二氧化碳混合、二氧化碳、一氧化二氮、臭氧和气溶胶)影响辐射传输的情况进行模拟计算;选择中国内陆地区18种大气廓线样本和4种大气模型,分别进行辐射传输计算,获得了3～5μm谱段分谱大气透过率和大气程辐射等,并比较了新选择通道(4.42～4.78μm)与传统通道(3.55～3.95μm)在地面和传输到大气层顸后辐亮度的变化情况,为今后应用新探测通道奠定了基础.     

温度箱入射窗方案与温度场模拟

介绍了夜视仪可靠性试验中温度应力试验箱入射窗的结构方案,并通过其上的加热器加热避免低温造成内层窗口玻璃结霜,且确保光通道中温度梯度尽量均匀,计算加热器所需功率,并使用ANSYS软件对温度场进行模拟。