中国富硒食品的生产现状及趋势

对硒的生物学作用和目前已经开发的富硒食品(富硒西瓜、富硒灵芝、富硒茶叶、富硒牛奶、富硒猪肉和富硒鸡蛋等)进行了概述。当前富硒食品的技术含量大多偏低,技术水平有待提高;价廉物美的富硒食品受市场欢迎,科学论证富硒食品的转化机制是今后科研的一个方向。     

微量元素硒与人体健康

综述了硒与人体健康的关系,包括：硒与心血管疾病、硒与肿瘤、硒与抗衰老、硒与免疫、硒与肝炎等的关系。     

硒缺乏的预防

防治硒缺乏可采用补硒方法。目前常用的补硒制剂主要包括有机物（硒蛋氨酸）和无机物（亚硒酸钠或硒酸钠）。硒主要在小肠吸收，人体对硒的吸收率很高，约为50％～100％。膳食来源的硒主要以硒蛋氨酸形式存在。硒蛋氨酸和硒酵母中生物结合形式的硒在直接消除氧自由基、抑制脂质过氧化方面，在激发免疫反应、促进免疫蛋白合成、刺激淋巴细胞增殖方面，在提高肝脏、肌肉中硒含量和提高肝GSH-Px活性方面，效果均明显好于无机硒化合物。与硒的无机盐相比，硒蛋氨酸不仅生物学活性高出许多，而且更容易被吸收，     

超声辅助酶法提取-原子荧光光谱法测定富硒黑木耳中硒形态

建立了富硒黑木耳中硒代胱氨酸、硒代半胱氨酸、亚硒酸、硒蛋氨酸、硒酸5种硒形态的液相色谱-原子荧光光谱分析方法。通过链酶蛋白酶E酶解,结合超声提取后,选取Hamilton PRP-X100离子交换色谱柱(250 mm×4.1 mm,10μm),40 mmol/L的磷酸氢二铵为流动相,在16 min内,5种硒形态完全达到基线分离。5种硒形态在线性范围内相关系数R为0.9990~0.9999;加标回收率为76.1%~108%;检出限分别为硒代胱氨酸0.35μg/L、甲基-硒代半胱氨酸0.46μg/L、亚硒酸0.26μg/L、硒代蛋氨酸0.64μg/L、硒酸3.06μg/L;方法应用于富硒黑木耳中硒形态的分析,精密度高、重现性好、方法稳定、准确可靠,是测定富硒黑木耳中硒形态含量的有效方法。     

硒蛋白及其分离分析

1957年Schwarz等证明硒是人体必需的微量元素之后,国内外开展了许多总硒及其生物化学作用的研究。大量事实表明硒与多种疾病相关,我国用补硒方法防治克山病获得成功,进一步证实了硒的营养作用。近年来,有关硒的生物医学作用的研究已逐渐从总硒转向对有机硒化合物的研究,后者主要集中于含硒氨基酸、含硒多肽、含硒蛋白和近几年才提出的含硒核酸。 就整个生物界来看,动物、植物和微生物中均发现有硒蛋白存在。在已发现的硒酶中,硒主要以硒半胱氨基酸(seCysH)形式存在于蛋白质的多肽链中。     

非金属元素硒的同素异形体*

结合史实文献和最新研究成果,汇总了硒的同素异形体,可分为气态硒、液态硒、固体硒、纳米硒和硒团簇等5类,重点介绍了固体硒、纳米硒和硒团簇的种类、结构、性质、制备和应用等。完善了硒同素异形体在教学中的深入介绍,有助于体现科学研究对本科教学内容改革的推进作用。     

生命的微量元素硒

硒是动物体必需的微量元素,对于硒的研究,古今中外积累了大量系统的资料,本文针对硒的营养、硒的代谢、硒的分子生物学与硒的补给方面作了综述,并对当前补硒现状谈了看法,仅供参考。     

硒-甲基硒代半胱氨酸的合成与拆分研究

天然硒-甲基硒代半胱氨酸为L型含硒氨基酸,是第21种人体必须氨基酸———硒代半胱氨酸的甲基化衍生物。1960年首次由Trelease S·F·等从美国黄芪中分离得到[1],它还广泛存在于大蒜、洋葱和椰菜等植物以及富硒酵母中。硒-甲基硒代半胱氨酸具有补硒、防治癌症、抗氧化、抗衰老、     

中国硒研究历史回顾（上）

过去50年中,中国微量元素科学和营养科学中最重要的发现,就是认识了硒对人体健康的重要性。在诸多微量元素中,没有哪一个元素能像硒那样对人类产生如此深刻而又广泛的影响。从硒的生物必需性、硒的生物效应两面性、硒的抗癌性、硒的延寿作用及富硒产品开发五个方面回顾了中国的硒研究历程。     

高效液相色谱与电感耦合等离子体质谱联用技术用于胁迫富硒海带硒形态研究

通过对海带胁迫富硒培养, 研究了海带对硒的富集总量及硒化学形态转变. 建立了反相离子对缓冲盐等3个色谱系统的高效液相色谱与电感耦合等离子体质谱联用(RP-HPLC-ICP-MS)技术测定亚硒酸钠、硒甲基半胱氨酸(MeSeCys)、硒代蛋氨酸(SeMet)三种硒形态. 采用3种提取溶剂, 超声提取缩短提取时间, 分离检测富硒海带的主要硒形态为亚硒酸钠、硒甲基半胱氨酸和硒代蛋氨酸.     

Contributions to the Chemistry of the Binary Compounds of the Transition Elements

Phase and structural relationships of the sulfur, selenium, and tellurium compounds of the 4d and 5d transition elements of groups IV to VII of the periodic system are discussed. Homologous elements behave very similarly with respect to the chalcogens, and this is particularly the case for niobium and tantalum, and for molybdenum and tungsten. However, zirconium, niobium, and molybdenum have a greater tendency towards formation of chalcogen-poor phases than their homologues hafnium, tantalum, and tungsten. Subchalcogenides are known only for zirconium and niobium. The number of phases and the tendency towards formation of solid solutions are considerably smaller among the tellurides than among the sulfides and selenides. The crystal structures of the telluride phases also differ from those of the sulfide and selenide phases of analogous composition. In addition, a review of the phase and structural relationships of the arsenic and antimony compounds of the 4d and 5d transition elements of groups V to VII is given.     

An integrated strategy of secondary metabolomics and glycomics to investigate multi-component variations in wine-processing of medicinal herbs and functional foods: A case study on Fructus Corni

Fructus Corni (FC), as a promising Chinese medicinal herb, has aroused considerable interest. Generally, FC needs to be processed according to the limited standard policy in China before clinical application, while the investigations on the specific processing methods (such as wine steaming or high-pressure wine steaming) are unclear. A comprehensive metabolomics strategy based on integrated non-targeted metabolomics and targeted glycomics in this paper was implemented to investigate the influences of the different processing technologies such as steaming, wine steaming, high-pressure steaming, high-pressure wine steaming, wine immersion, and wine stir-frying on FC, respectively. UHPLC-Q-TOF-MS/MS was employed for identifying and distinguishing the secondary metabolites. A total of 85 components were identified in all groups. The results of PCA score plots showed that the crude and processed samples had a complete separation, and wine steamed and high-pressure wine steamed samples could be a category, indicating that the two processed products had a similar quality. Multiple chromatography including HPLC (C₁₈)-PDA, HPLC (NH₂)-ELSD, and HPGPC-ELSD was used for determining the molecular weight distributions, the monosaccharide compositions of polysaccharides, and the contents of free monosaccharides and oligosaccharides. The results indicated that the content and composition of saccharides were different in crude and different processed FC. The polysaccharides were composed of fucose, arabinose, galactose, glucose, galacturonic acid, mannose and rhamnose, and the free monosaccharides were composed of fucose, arabinose, galactose, glucose, mannose, rhamnose and fructose in all FC samples. The PCA score plots of the glycomics indicated that the crude and high-pressure wine steamed FC could be a category, showing that the two groups had similar chemical compositions. Ultimately, the simulation processing experiments indicated that the transformation of morroniside, polysaccharides, oligosaccharides, fructose, and glucose to 5-HMF through the reactions of dehydration and deglycosylation was the potential mechanism of enhancing the effects by processing. Conclusionly, the saccharides should be investigated as thoroughly as the secondary metabolites, and the high-pressure wine steamed FC could be an alternative to wine steamed FC.     

“蛋黄-蛋壳”结构纳米反应器的设计、调控及在锂硫电池正极中的应用研究

锂硫电池具有理论能量密度高等优势,被认为是最有前景的一类新型二次电池.硫正极存在硫和硫化锂的导电性差、可溶性多硫化物的扩散/穿梭、循环过程中硫的体积膨胀以及氧化还原过程慢等问题,严重制约着电池的活性和循环稳定性.设计“蛋黄-蛋壳”结构纳米反应器应用于锂硫电池正极,可通过调控其“蛋黄”、“蛋壳”和“空腔”结构缓解充放电过程中电极的体积变化,为离子/电子输运提供快速通道,强化对多硫化物的吸附和催化转换作用等,进而提高电极的活性和循环性能,有利于推进锂硫电池的商业化进程.本文总结了“蛋黄-蛋壳”结构纳米反应器的设计和调控策略,包括单核-单壳、单核-多壳、多核-单壳以及多核-多壳等,并结合锂硫电池的工作特点和目前应用存在的问题,对未来发展前景进行了展望.     

纳米粒子的精准组装

纳米材料由于其独特的光、电、磁、力学等性质,成为了构建功能材料与器件的理想基元。实现纳米粒子的精确组装,是探究粒子之间的耦合聚集性质和制备宏观功能器件的基础。但是由于纳米粒子的小尺寸以及在溶液中运动的随机性与复杂性,精准控制纳米粒子组装体的形貌以及在空间中的相对位置仍存在巨大挑战。为了将纳米粒子组装成理想的有序结构,许多控制粒子组装的策略与方法得到发展。本文首先概述了纳米粒子自组装的控制方法与典型形貌,着重分析了影响粒子精准排布的因素与控制方法,并对纳米粒子及其组装体的光学性质与器件应用的最新研究进展进行了讨论,最后对目前纳米粒子精准组装所面临的挑战以及未来发展的方向进行了展望。     

Poly(lactide) stereocomplexes: formation, structure, properties, degradation, and applications

Poly(lactide)s [i.e. poly(lactic acid) (PLA)] and lactide copolymers are biodegradable, compostable, producible from renewable resources, and nontoxic to the human body and the environment. They have been used as biomedical materials for tissue regeneration, matrices for drug delivery systems, and alternatives for commercial polymeric materials to reduce the impact on the environment. Since stereocomplexation or stereocomplex formation between enantiomeric PLA, poly(L-lactide) [i.e. poly(L-lactic acid) (PLLA)] and poly(D-lactide) [i.e. poly(D-lactic acid) (PDLA)] was reported in 1987, numerous studies have been carried out with respect to the formation, structure, properties, degradation, and applications of the PLA stereocomplexes. Stereocomplexation enhances the mechanical properties, the thermal-resistance, and the hydrolysis-resistance of PLA-based materials. These improvements arise from a peculiarly strong interaction between L-lactyl unit sequences and D-lactyl unit sequences, and stereocomplexation opens a new way for the preparation of biomaterials such as hydrogels and particles for drug delivery systems. It was revealed that the crucial parameters affecting stereocomplexation are the mixing ratio and the molecular weight of L-lactyl and D-lactyl unit sequences. On the other hand, PDLA was found to form a stereocomplex with L-configured polypeptides in 2001. This kind of stereocomplexation is called "hetero-stereocomplexation" and differentiated from "homo-stereocomplexation" between L-lactyl and D-lactyl unit sequences. This paper reviews the methods for tracing PLA stereocomplexation, the methods for inducing PLA stereocompelxation, the parameters affecting PLA stereocomplexation, and the structure, properties, degradation, and applications of a variety of stereocomplexed PLA materials.     

Green synthesis of biogenic metal nanoparticles by terrestrial and aquatic phototrophic and heterotrophic eukaryotes and biocompatible agents

The size, shape and controlled dispersity of nanoparticles play a vital role in determining the physical, chemical, optical and electronic properties attributing its applications in environmental, biotechnological and biomedical fields. Various physical and chemical processes have been exploited in the synthesis of several inorganic metal nanoparticles by wet and dry approaches viz., ultraviolet irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques. However, these methodologies remain expensive and involve the use of hazardous chemicals. Therefore, there is a growing concern for the development of alternative environment friendly and sustainable methods. Increasing awareness towards green chemistry and biological processes has led to a necessity to develop simple, cost-effective and eco-friendly procedures. Phototrophic eukaryotes such as plants, algae, and diatoms and heterotrophic human cell lines and some biocompatible agents have been reported to synthesize greener nanoparticles like cobalt, copper, silver, gold, bimetallic alloys, silica, palladium, platinum, iridium, magnetite and quantum dots. Owing to the diversity and sustainability, the use of phototrophic and heterotrophic eukaryotes and biocompatible agents for the synthesis of nanomaterials is yet to be fully explored. This review describes the recent advancements in the green synthesis and applications of metal nanoparticles by plants, aquatic autotrophs, human cell lines, biocompatible agents and biomolecules.     

A review on elastic graphene aerogels: Design,preparation, and applications

Graphene aerogels with unique properties, such as ultralow density, super-elasticity, high specific surface area, and excellent thermal stability, have undergone great progress in the past decades. Especially, super-elastic graphene aerogels provide a highly attention-catching platform for developing advanced energy devices, pressure sensors, contaminates adsorbents, and electromagnetic wave shielding and absorption materials, and so forth. In this review, we begin with the introduction and discussion of various fabrication techniques and compare their advantages and disadvantages, focusing on the template-free assembly process and template-assisted assembly process. Then, we summarize the factors influencing the compressibility and elasticity of graphene aerogels, including intrinsic properties of building blocks, constituent materials, and structure design, and their wide applications. At the end, we discuss the current challenges and future prospects of this field.     

纳米粒子与细胞相互作用的力学-化学偶联研究进展

纳米粒子在生物医学和大气环境领域的广泛研究使得其生物安全性越来越受到重视。目前已经有许多研究关注纳米粒子与细胞的相互作用及细胞毒性问题。本综述从细胞力学-化学偶联的角度总结了近五年来有关纳米粒子与细胞相互作用的研究进展。首先介绍了与细胞力学-化学偶联性质相关的分子基础以及目前检测细胞机械性质的纳米技术,然后重点讨论了纳米粒子对细胞粘附、骨架、刚度和迁移性质的影响。在此基础上,进一步指出了纳米生物力学-化学偶联的挑战与展望。     

无机-无机复合电致变色材料的研究进展

在外加电压的作用下,电致变色材料的光学性能（颜色、透光率等）能够可控制、可逆地变化,在节能减排领域有重要应用前景。随着相关研究的不断创新、深入和拓展,单一组分的电致变色材料因受到其自身结构和性能的限制,不能表现出人们所期望的电致变色性能,并且在结构和性能上不具有可设计和调控性,因而越来越无法满足实际应用的需求。与非复合电致变色材料相比较,复合型材料在这方面具有明显的优势,其优势体现在通过合理的材料设计,借助复合材料各组分的协调作用,充分激发各组分的优点,克服各自的缺点,可以获得结构和性能优异的电致变色材料。因此,近年来越来越多的研究聚焦于复合型电致变色材料。目前已开展研究的复合型电致变色材料的种类很多,根据复合组分是无机材料还是有机材料来对复合型电致变色材料分类的话主要可分为无机-无机复合、无机-有机复合和有机-有机复合3大类。相比有机电致变色材料,无机电致变色材料在材料成分控制、机械性能、光调制、使用稳定性、寿命等方面优势显著,因此,单一组分的和复合型的无机电致变色材料始终是本领域研究的重要方向。因此,本文致力于近年来无机-无机复合电致变色材料、器件和电解质的研究现状和未来的发展动态,对其研究进展、所存在的问题和发展趋势进行了归纳总结,为复合型电致变色材料的进一步研发和应用提供依据。