A lysosomal polarity-specific two-photon fluorescent probe for visualization of autophagy

Autophagy plays a vital role in maintaining the balance of normal physiological state of living cells. In this paper, a polarity-specific two-photon fluorescent probe Lyso-NA based on naphthalimide was synthesized for the purpose of monitoring autophagy during biological research. The results of photophysical properties and theoretical calculation confirmed that different polarities of solvents mainly effected fluorescent intensities of probe. Fluorescent intensity, quantum yield and fluorescence lifetime of probe kept a good linear relationship with polarity respectively. In addition, due to its low toxicity and selective accumulation in lysosomes, Lyso-NA is suitable for detecting changes in lysosomal polarity of living cells. Compare with the imaging results of plasmid transfection, a better performed real-time long-term fluorescent visualization of autophagy in living cells was achieved. Probe Lyso-NA can work as an efficient and cost effective imaging tool for visualizing autophagy in living cells.     

皂素皂苷脂肪链中甲基绝对构型的确定

利用Sharpless环氧化和Roush反应合成了皂素苷脂肪链中C9脂肪酸单体的两个非对映异构体,即(3S,5S,6S)-3,5-二羟基-6-甲基-δ-辛酸内酯和(3S,5S,6R)-3,5-二羟基-6-甲基-δ-辛酸内酯。通过与天然样品进行理化数据对比,确定了皂素皂苷脂肪链中甲基的绝对构型为S。     

Recent advances in layered LiNi x CoyMn1−x−y O2 cathode materials for lithium ion batteries

Lithium cobalt oxide, LiCoO₂, has been the most widely used cathode material in commercial lithium ion batteries. Nevertheless, cobalt has economic and environmental problems that leave the door open to exploit alternative cathode materials, among which LiNi _x Co_yMn_{1 − x − y} O₂ may have improved performances, such as thermal stability, due to the synergistic effect of the three ions. Recently, intensive effort has been directed towards the development of LiNi _x Co _y Mn_{1 − x − y} O₂ as a possible replacement for LiCoO₂. Recent advances in layered LiNi _x Co_yMn_{1 − x − y} O₂ cathode materials are summarized in this paper. The preparation and the performance are reviewed, and the future promising cathode materials are also prospected.     

Digital moiré fringe measurement method for alignment in imprint lithography

Accurate layer-to-layer alignment, which is of prime importance for the fabrication of multilayer nanostructures in integrated circuits, is one of the main obstacles for imprint lithography. Current alignment measurement techniques commonly involve an image detection process for coarse alignment followed by a grating interference process for fine alignment. Though this kind of two-level alignment system is reasonable for measurement, when it is used in real imprint lithography, it is inconvenient because of the existence of a complex loading system that needs space for alignment. In this study, we propose a fine alignment method using only image detection using grating images and digital moiré fringe technology. In this method, though the gratings are also selected as alignment marks for accurate measurement, they do not interfere with the physics. The grating images captured from the template and wafer are used to measure angular displacement and to form parallel digital moiré fringes. The relative linear displacement between the template and wafer is determined by detecting the spatial phase of parallel digital moiré fringes. Owing to the magnification effect of digital moiré fringes, this method is capable of generating accurate measurements. According to the experimental results, this digital moiré fringe technique is accurate to less than 10 nm. In addition, without a complex grating interference system, this method has the advantage of being easy to operate.     

Practical approach for the stereoselective introduction of beta-arabinofuranosides

A practical approach for the stereoselective introduction of beta-arabinofuranosides has been developed on the basis of locking an arabinosyl donor in a conformation in which nucleophilic attack from the beta face is favored. The new glycosyl donor was designed by analyzing optimized geometries of low-energy conformers of the arabinofuranosyl oxacarbenium ion. The Newman projection of the E(3) conformer indicated that nucleophilic attack from the alpha face is disfavored because an eclipsed H-2 will be encountered. On the other hand, an approach from the beta face was expected to be more favorable, because it will experience only staggered substituents. The arabinofuranosyl oxacarbenium ion could be locked in the E(3) conformation by employing a 3,5-O-di-tert-butylsilane protecting group, which places C-5 and O-3 in a pseudoequatorial orientation, resulting in a perfect chair conformation of the protecting group. The new glycosyl donor gave excellent beta selectivities in a range of glycosylations with glycosyl acceptors having primary and secondary alcohols. The attractiveness of the new methodology was demonstrated by the chemical synthesis of a fragment of arabinogalactan, which is an important constituent of the primary plant cell wall.     

Few-layer graphene film fabricated by femtosecond pulse laser deposition without catalytic layers

The films of few-layer graphene are formed through laser exfoliation of a highly ordered pyrolytic graphite(HOPG), without a catalytic layer for the growth process. The femtosecond(fs) laser exfoliation process is investigated at different laser fluences and substrate temperature. For fs laser exfoliation of HOPG, the few-layer graphene is obtained at 473 K under an optimal laser fluence. The formation of few-layer graphene is explained by removal of intact graphite sheets occurred by an optimal laser fluence ablation. The new insights may facilitate the controllable synthesis of large area few-layer graphene.     

Molecular dynamics simulations of La2O3 thin films on SiO2

Classical molecular dynamics is used to investigate the equilibrium state of the surface region and interface of heteroepitaxial La2O3 thin films.Due to the lattice mismatch,heteroepitaxial thin films are subject to very large stress.For this reason the behavior of La2O3 thin films at SiO2interface becomes an important concern.Our result indicates that La2O3 can uniformly wet SiO2 surface.The properties of the simulated films are analyzed and the lack of any discernible crystalline phase in epitaxial La2O3 on SiO2 indicates that the lattice mismatch between SiO2 and La2O3 is sufficiently large to prevent the formation of even short-range orders in La2O3 film.     

Cross-linking copolymers of acrylates’ gel electrolytes with high conductivity for lithium-ion batteries

The cross-linking gel copolymer electrolytes containing alkyl acrylates, triethylene glycol dimethacrylate, and liquid electrolyte were prepared by in situ thermal polymerization. The gel polymer electrolytes containing 15 wt% polymer content and 85 wt% liquid electrolyte content with sufficient mechanical strength showed the high ionic conductivity around 5?×?10^?3 Scm^?1 at room temperature. The gel electrolytes containing different polymer matrices were prepared, and their physical observation and conductivity were discussed carefully. The cross-linking copolymer gel electrolytes of alkyl acrylates with other monomers were designed and synthesized. The results showed that copolymerization can improve the mechanical properties and ionic conductivities of the gel electrolytes. The polymer matrices of gels had excellent thermal stability and electrochemical stability. The scanning electron microscope analysis showed the gel electrolyte was the homogeneous structure, and the cross-linking polymer host was the porous three-dimensional network structure, which demonstrated the high conductivity of the gel electrolytes. The gel polymer Li-ion battery was prepared by this in situ thermal polymerization. The cell exhibited high charge-discharge efficiency at 0.1 C. The results of LiFePO4-PEA-Li cell and graphite-PEA-Li cell showed that gel polymer electrolytes have good compatibility with the battery electrodes materials.     

A 200‐fold Quantum Yield Boost in the Photoluminescence of Silver‐Doped AgxAu25−x Nanoclusters: The 13 th Silver Atom Matters

The rod‐shaped Au₂₅ nanocluster possesses a low photoluminescence quantum yield (QY=0.1 %) and hence is not of practical use in bioimaging and related applications. Herein, we show that substituting silver atoms for gold in the 25‐atom matrix can drastically enhance the photoluminescence. The obtained Ag_xAu_25?x (x=1–13) nanoclusters exhibit high quantum yield (QY=40.1 %), which is in striking contrast with the normally weakly luminescent Ag_xAu_25?x species (x=1–12, QY=0.21 %). X‐ray crystallography further determines the substitution sites of Ag atoms in the Ag_xAu_25?x cluster through partial occupancy analysis, which provides further insight into the mechanism of photoluminescence enhancement.     

子痫前期患者CD4+CD25+调节 性T细胞亚群的改变及意义

目的 探讨子痫前期患者CD4+CD25+调节性T细胞（Treg）亚群改变及在PE免疫耐受失衡中的作用。方法 选 取PE 患者（观察组）30 例,同期正常晚期妊娠（对照组）20 例。分别采集PE 患者和正常晚期妊娠妇女外周血,采用流式细胞术检测Treg 以及活化记性相关（CD45RO、HLA-DR）、归巢相关（CCR4、CCR6、CD103）、功能相关（ICOS、CTLA-4、Galectin 1）和生存相关（PD1 和CD95）标记分子的表达。采用免疫抑制实验检测外周血中Treg 的免疫抑制功能。结果 观察组患者外周血CD4+CD25+细胞的比例[(5.87±3.34) %]低于对照组[（6.65±1.18）%],但差异无统计学意义。免疫抑制实验显示观察组患者外周血中Treg 对CD4+CD25-T 细胞的增值抑制作用与对照组无统计学差异。通过对Treg 多个标记分子的检测进一步发现,ICOS 和CCR6 在观察组Treg 上的表达水平显著低于对照组Treg（均P＜0.01）;CCR4 和Galectin 1的表达水平较对照组低,而CD45RO、HLA-DR 、CD103、CTLA、PD1 和CD95 的表达水平较对照组高,但两组间差异均无统计学意义（均P＞0.05）。结论 Treg 亚群比例失调可能是导致子痫前期发生的重要因素。