Habitat-induced reciprocal transformation in the root phenotype of Oriental ginseng is associated with alteration in DNA methylation

Oriental ginseng is an important medicinal plant that grows in 2 major forms or ecotypes, wild and domesticated. Each form differs conspicuously in root phenotype, but can be converted from one type to another by habitat. Here we show that the habitat-induced transformation of ginseng root phenotype was accompanied by alteration in cytosine methylation at a large number of 5′-CCGG-3′ sites detected by the methylation-sensitive polymorphism (MSAP) marker. The collective CG and CHG methylation levels of all 4 landraces of the domesticated form were significantly lower than those of the wild form. Interestingly, artificially transplanted ginseng plants recreated in both directions the methylation levels (at least in CHG) of their natural counterparts. The methylation differences between the 2 ginseng ecotypes were validated at 2 isolated MSAP loci bearing homology to a 5S rRNA gene or a copia retrotransposon. Our results implicate a link between epigenetic variation and habitat-induced phenotypic flexibility in Oriental ginseng.     

浅谈三维动画的应用与制作

本文简洁阐述了三维动画的应用范围及意义,介绍了三维动画的基本制作原理和技术制作的基本方法,提供了一种制作三维动画的捷径.     

填充方钴矿热电材料:从单填到多填

以传统窄带半导体材料为主要对象的高性能热电材料研究近年来发展迅速并取得了明显进展.本文以含本征晶格孔洞的笼状结构CoSb3基方钴矿化合物的相关研究为主线,综述近年来热电材料的主要研究进展,并分析了杂质原子在孔洞中部分填充特性为基础的填充方钴矿化合物的结构调控、电-热输运性能协同调控、以及热电性能优化的内在物理机制及其实验实现.在本征孔洞结构的方钴矿化合物中引入部分填充的杂质原子,通过局域声子散射而显著降低晶格热导率,同时可以优化电输运性能.研究还发现这样一类特殊结构化合物的电热输运性能可以通过选择不同价态与不同局域振动频率的多种不同填充原子的组合填充而实现可以近乎独立地调控与优化,热电优值达到1.7@850K,实现了明显具有声子玻璃-电子晶体特征的一类高性能热电材料.研究工作一方面明显提高了填充方钴矿材料的热电性能,另一方面加深了相关物理机制的理解,对进一步的新热电材料体系的设计具有指导意义.     

In vitro and in vivo studies on biodegradable magnesium alloy

The microstructure, mechanical property, electrochemical behavior and biocompatibility of magnesium alloy(Bio De MSM^TM) were studied in the present work. The experimental results demonstrated that grain refining induced by extrusion improves the alloy strength significantly from162 MPa for the as-cast alloy to 241 MPa for the as-extruded one. The anticorrosion properties of the as-extruded alloy also increased.Furthermore, the hemolysis ratio was decreased from 4.7% for the as-cast alloy to 2.9% for the as-extruded one, both below 5%. Bio De MSM^TMalloy shows good biocompatibility after being implanted into the dorsal muscle and the femoral shaft of the New Zealand rabbit, respectively, and there are no abnormalities after short-term implantation. In vivo observation indicated that the corrosion rate of this alloy varies with different implantation positions, with higher degradation rate in the femur than in the muscle.     

人造沸石负载铜催化剂催化苯酚羟化反应研究

考察了以离子交换法制备负载Cu的人造沸石为催化剂在水溶液中催化苯酚羟基化反应中的性能。研究了催化剂铜负载量、催化剂用量、H2O2用量、反应时间、反应温度等条件苯酚转化率和苯二酚选择性的影响。实验结果表明,铜负载量为3%的铜离子交换沸石表现出了良好的催化活性和苯二酚的选择性。在优化条件下,苯酚转化率可达到49%以上,苯二酚的选择性大于97%。回收催化剂的活性可通过将回收的催化剂于550℃条件下煅烧1 h加以恢复。     

Variability and reduction of atmospheric pollutants in Beijing and its surrounding area during the Beijing 2008 Olympic Games

The Beijing-Tianjin-Hebei Atmospheric Environment Monitoring Network was established by the Institute of Atmospheric Physics, Chinese Academy of Sciences. The goals of the network were to monitor and provide warnings of the atmospheric quality in Beijing and its surrounding area during the Beijing 2008 Olympic Games. The results showed that the atmospheric complex pollution exhibited high concentrations of ozone and fine particles and oxidation in summer, with a ubiquitous regional source. The regional mean concentrations of SO₂, PM_2.5, NO₂, and O_{3_8h max} (the maximum daily 8 h mean) and O_x were 22±11, 90±40, 25±5, 136±35 and 112±21 μg/m³ in summer, respectively. During the Olympic Games, the mean concentration of SO₂, PM_2.5, NO_{2, O3_8h} max, and O_x were 12.5±4, 56±28, 23±4, 114±29, 95±17 μg/m³ in the region, respectively, and fell by 51.0%, 43.7%, 13%, 20.2%, and 18.9%, respectively, compared to the prophase mean before the Olympic Games. The concentration of atmospheric pollutants declined significantly and achieved the “Green Olympics” control goal of air quality. After the Olympic Games, SO₂, PM_2.5 and NO_x increased significantly as the temporary atmospheric pollution control measures were terminated.     

Quantum secure direct communication and authentication protocol with single photons

A quantum secure direct communication and authentication protocol is proposed by using single photons. An information transmission is completed by sending photons once in quantum channel, which improves the efficiency without losing the security. The protocol encodes identity-string of the receiver as single photons sequence, which acts as detection sequence and implements authentication. Before secret message is encoded as single photons sequence, it is encrypted with identity-string of the sender by using XOR operation, which defends quantum teleportation attack efficiently. The base identity-strings of the sender and the re- ceiver are reused unconditionally secure even in noisy channel. Compared with the protocol proposed by Wang et al. （Phys Lett A, 2006, 358： 256--258）, the protocol in this study sends photons once in one transmission and defends most attacks including ＇man-in-the-middle＇ attack and quantum teleportation attack efficiently.     

The effect of inhomogeneous water on seismic imaging in deepwater areas of the South China Sea

This paper examines the effect of inhomogeneous water on seismic imaging in deep water areas. An appropriate partial differen- tial equation is derived for the acoustic pressure field in inhomogeneous water, including current effects. Seismic wavefields are simulated and the results show that the traveltime of seismic waves can be affected. The maximum traveltime perturbation at zero offset is 20 ms. In particular, the structure of horizontal reflectors below the water is distorted by mesoscale eddies. Variations of water temperature are the fundamental cause of the distortion. Finally, a calibration method for the distortion of seismic imaging caused by inhomogeneous water is presented.     

Analysis of biomarkers for the cross-linkage of formaldehyde with bovine serum albumin peptides

Formaldehyde, a well-known environmental toxic hazard, has been found to produce endogenously via semicarbazide-sensitive amine oxidase-catalyzed oxidative deamination of methylamine. In diabetes, the activity of SSAO has been found to increase with a subsequent increase in endogenous formaldehyde production. It has been postulated that SSAO-induced production of formaldehyde may be involved in the alteration of protein structure, which may subsequently cause protein deposition associated with chronic pathological disorders. Formaldehyde has also been found to react （cross-link） with amino group of the N-terminal amino acid residue and with the side-chains of arginine, cysteine, histidine and lysine residues. Therefore, formaldehyde may be responsible, at least in part, for protein cross-linkage, oxidative stress and cytotoxicity. The cross-linking of formaldehyde with bovine serum albumin was studied using LC-MS and Mascot database. The peptides sequence for control BSA （untreated） digested with trypsin was matched in the online database search query by exporting the MS/MS data to online MASCOT database. In this way, a total of twenty-seven peptides were matched in the database search query. These twenty-seven peptides were then searched manually in all of the tryptic BSA samples treated with different concentrations of FA that were incubated in different time intervals. Six formaldehyde-treated BSA peptides （FKDLGEEHFK, HLVDEPQNLIK, KVPQVSTPTLVEVSR, RPCFSALTPDETYVPK, LVNELTEFAK, DAFLGSFLYEYSR） were found to be the possible markers for formaldehyde-protein/peptides adducts.     

复合型酸化缓蚀剂的性能研究

以喹啉为母体,配以有机胺和芳香族化合物,与卤代烃反应合成了一种复合缓蚀剂。采用静态失重法和电化学法评价了缓蚀剂的缓蚀性能,分析了缓蚀机理,并与目前国内常用的酸化缓蚀剂缓蚀效果进行了对比。结果表明,复合缓蚀剂为阳极抑制为主的混合型缓蚀剂,能够有效抑制盐酸对N80碳钢的腐蚀,比目前使用的缓蚀剂性能更优。