Vertically Aligned Hybrid Core/Shell Semiconductor Nanowires for Photonics Applications

A family of 1D organic/inorganic core/shell materials formed by an inner organic nanowire (ONW) conformally covered with an inorganic wide band gap semiconductor (ZnO or TiO₂) layer is presented. The developed procedure is a two‐steps vacuum methodology involving the formation of supported single crystal small‐molecule nanowires by physical vapor deposition and plasma enhance chemical vapor deposition (PECVD) of the inorganic shell. Critical characteristics of the last technique are the possibilities of low temperature and remote configuration deposition. Additionally, an initial step has to be included in order to create nucleation centers for the growth of the ONWs. The procedure and its general character in terms of the variability in organic core and inorganic shells composition and the applicability of the technique to different substrates are presented. The formation of the inorganic shell with no damage of the organic core single‐crystalline structure is demonstrated by high resolution transmission electron microscopy. The vertical alignment of the hybrid nanostructure is achieved thanks to the interaction of the 1D organic nanostructured surfaces and the glow discharge during the deposition of the inorganic shell by PECVD. The optical properties of these core/shell NWs are studied by fluorescence spectroscopy and microscopy, and their application as nanoscale waveguides in the 550–750 nm range addressed.     

Nanosecond and femtosecond mass spectroscopic analysis of a molecular beam produced by the spray-jet technique

The spray-jet molecular beam apparatus enabled us to produce a molecular beam of non-volatile molecules under high vacuum from a sprayed mist of sample solutions. The apparatus has been used in spectroscopic studies and as a means of molecular beam deposition. We analyzed the molecular beam, consisting of non-volatile, solvent, and carrier-gas molecules, by using femtosecond- and nanosecond- laser mass spectroscopy. The information thus obtained provided insight into the molecular beam produced by the spray-jet technique.     

Pathogenic Mutations Shift the Equilibria of α‐Synuclein Single Molecules towards Structured Conformers

α‐synuclein (α‐Syn) is an abundant brain protein whose mutations have been linked to early‐onset Parkinson's disease (PD). We recently demonstrated, by means of a single‐molecule force spectroscopy (SMFS) methodology, that the conformational equilibrium of monomeric wild‐type (WT) α‐Syn shifts toward β‐containing structures in several unrelated conditions linked to PD pathogenicity. Herein, we follow the same methodology previously employed for WT α‐Syn to characterize the conformational heterogeneity of pathological α‐Syn mutants A30P, A53T, and E46K. Contrary to the bulk ensemble‐averaged spectroscopies so far employed to this end by different authors, our single‐molecule methodology monitored marked differences in the conformational behaviors of the mutants with respect to the WT sequence. We found that all the mutants have a much higher propensity than the WT to adopt a monomeric compact conformation that is compatible with the acquiring of β structure. Mutants A30P and A53T show a similar conformational equilibrium that is significantly different from that of E46K. Another class of conformations, stabilized by mechanically weak interactions (MWI), shows a higher variety in the mutants than in the WT protein. In the A30P mutant these interactions are relatively stronger, and therefore the corresponding conformations are possibly more structured. The more structured and globular conformations of the mutants can explain their higher propensity to aggregate with respect to the WT.     

Single molecule fluorescence autocorrelation measurement on anisotropic molecular diffusion in nematic liquid crystal

Diffusion kinetics of three dyes in nematic liquid crystals are studied with single-molecule fluorescence autocorrelation spectroscopy. Markedly large anisotropy was observed in the diffusion coefficient and structure of diffusion molecules showed no marked effect on the anisotropy.     

Neumann原理与分子的转动性质

给出分子惯量张量的并矢式,利用标量场性质得到惯量张量的示性曲面,根据Neumann原理讨论各种点群分子惯量张量示性面的特点,给出分子惯量张量沿不同方向值的分布规律及角动量与角速度共线的方向.     

多苯环树枝状化合物的合成及对荧光小分子荧光作用研究

以均苯四甲酸酐（PMDA）和二乙醇胺（DEA）为原料,制备均苯四甲酰四二乙醇胺（PTDA）,用小分子荧光体3,5-二羟基苯甲酸（3,5-DAC）修饰PTDA,合成多苯环树枝状化合物（PTDA -3,5-DAC）。通过红外光谱、核磁共振表征了其结构。研究了PTDA -3,5-DAC与荧光小分子（曙红B、罗丹明B、亚甲基蓝和达旦黄）组成的能量转移体系中,荧光小分子荧光强度的变化。实验结果表明,合成PTDA -3,5-DAC的最佳条件：反应温度为160℃,反应时间为4 h,催化剂对甲苯磺酸用量为2.0%,反应程度为75.67%。PTDA -3,5-DAC作用于曙红B和亚甲基蓝的DMF溶液,荧光强度逐渐降低;作用于罗丹明B的DMF溶液,荧光强度先增大后减小;作用于达旦黄的DMF溶液,荧光强度有较小程度的增强。     

Structural Determinants of the Selectivity of 3‐Benzyluracil‐1‐acetic Acids toward Human Enzymes Aldose Reductase and AKR1B10

The human enzymes aldose reductase (AR) and AKR1B10 have been thoroughly explored in terms of their roles in diabetes, inflammatory disorders, and cancer. In this study we identified two new lead compounds, 2‐(3‐(4‐chloro‐3‐nitrobenzyl)‐2,4‐dioxo‐3,4‐dihydropyrimidin‐1(2H)‐yl)acetic acid (JF0048, 3 ) and 2‐(2,4‐dioxo‐3‐(2,3,4,5‐tetrabromo‐6‐methoxybenzyl)‐3,4‐dihydropyrimidin‐1(2H)‐yl)acetic acid (JF0049, 4 ), which selectively target these enzymes. Although 3 and 4 share the 3‐benzyluracil‐1‐acetic acid scaffold, they have different substituents in their aryl moieties. Inhibition studies along with thermodynamic and structural characterizations of both enzymes revealed that the chloronitrobenzyl moiety of compound 3 can open the AR specificity pocket but not that of the AKR1B10 cognate. In contrast, the larger atoms at the ortho and/or meta positions of compound 4 prevent the AR specificity pocket from opening due to steric hindrance and provide a tighter fit to the AKR1B10 inhibitor binding pocket, probably enhanced by the displacement of a disordered water molecule trapped in a hydrophobic subpocket, creating an enthalpic signature. Furthermore, this selectivity also occurs in the cell, which enables the development of a more efficient drug design strategy: compound 3 prevents sorbitol accumulation in human retinal ARPE‐19 cells, whereas 4 stops proliferation in human lung cancer NCI‐H460 cells.     

New,Non‐quinone Fluorogeldanamycin Derivatives Strongly Inhibit Hsp90

Streptomyces hygroscopicus is a natural producer of geldanamycin. Mutasynthetic supplementation of an AHBA‐blocked mutant with all possible monofluoro 3‐aminobenzoic acids provided new fluorogeldanamycins. These showed strong antiproliferative activity and inhibitory effects on human heat shock protein Hsp90. Binding to Hsp90 in the low nanomolar range was determined from molecular modelling, AFM analysis and by calorimetric studies.     

Structurally Diverse Polyamines: Solid‐Phase Synthesis and Interaction with DNA

A versatile solid‐phase approach based on peptide chemistry was used to construct four classes of structurally diverse polyamines with modified backbones: linear, partially constrained, branched, and cyclic. Their effects on DNA duplex stability and structure were examined. The polyamines showed distinct activities, thus highlighting the importance of polyamine backbone structure. Interestingly, the rank order of polyamine ability for DNA compaction was different to that for their effects on circular dichroism and melting temperature, thus indicating that these polyamines have distinct effects on secondary and higher‐order structures of DNA.     

当归多糖对DPN大鼠TLR4/MyD88/NF-κB通路抑制影响

目的: 分析当归多糖对糖尿病神经病变（DPN）大鼠TLR4/MyD88/NF-κB通路抑制影响。方法: 选取SPF级Wistar雄性大鼠105只,随机选取15只作为正常组,剩余90只大鼠制备DPN模型,成功造模75只,随机分成5组,模型组、当归多糖低、中、高剂量组和阳性对照组,每组15只。模型组和正常组大鼠采用2 mL/100 g生理盐水灌胃,当归多糖低、中、高剂量组大鼠给予当归多糖药液灌胃,阳性对照组给予弥可保+二甲双胍溶液灌胃,每日给药体积均为2 mL/100 g。每天1次,连续灌胃10 d。给药3、10 d后检测大鼠机械缩足反应阈值（PWT）、热缩足反射潜伏期（PWL）,末次给药后检测大鼠空腹血糖、血清丙二醛（MDA）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性、谷胱甘肽过氧化物酶（GSH-Px）、白细胞介素-6（IL-6）、髓鞘碱性蛋白（MBP）、TNF-α及C反应蛋白（CRP）含量,检测大鼠运动神经传导速度（MNCV）、感觉神经传导速度（SNCV）,大鼠坐骨神经内核因子-κB（NF-κB） mRNA、髓样分子因子88（MyD88） mRNA及Toll样受体4（TLR4） mRNA表达。结果: 模型组及当归多糖低剂量组大鼠空腹血糖、MDA含量显著高于正常组,CAT、SOD及GSH-Px含量显著低于正常组,当归多糖中、高剂量组大鼠空腹血糖、MDA含量显著低于模型组、阳性对照组,CAT、SOD及GSH-Px含量显著高于模型组、阳性对照组,差异有统计学意义（P＜0.05）;模型组、当归多糖低剂量组大鼠血清IL-6、MBP、TNF-α及CRP含量均显著高于正常组,当归多糖中、高剂量组大鼠血清IL-6、MBP、TNF-α及CRP含量均显著低于模型组、阳性对照组,差异有统计学意义（P＜0.05）;模型组、当归多糖低剂量组大鼠NF-κB mRNA、MyD88 mRNA及TLR4 mRNA表达量均显著高于正常组,当归多糖中、高剂量组大鼠NF-κB mRNA、MyD88 mRNA及TLR4 mRNA表达量均显著低于模型组、阳性对照组,差异有统计学意义（P＜0.05）。结论: 当归多糖可显著改善DPN大鼠的周围神经损伤状态,促进神经传导的恢复,其机制可能与阻断TLR4/MyD88/NF-κB信号路径的转导,降低炎性因子水平,减轻神经的氧化应激损伤有关。