Blue phase III widening in CE6-dispersed surface-functionalised CdSe nanoparticles

The phase transition behaviour of the chiral liquid crystal CE6 doped with spherical surface-functionalised CdSe nanoparticles has been examined by means of high-resolution adiabatic scanning calorimetry and polarising microscopy. The addition of nanoparticles results in an essentially stabilised blue phase III. The phase diagram is displayed upon heating and cooling and the enthalpy changes involved in the conversion between the blue phases are determined. The dispersion of functionalised nanoparticles is prominent for the stabilisation of blue phase III, which is potentially useful for applications, especially if applied on liquid crystals that exhibit blue phases close to room temperature.     

双萘酰亚胺衍生物用于检测水溶液中的苦味酸

设计合成了一个新的双1,8-萘酰亚胺衍生物(Bis-Nph), 并通过核磁共振波谱和高分辨质谱鉴定了其结构. Bis-Nph呈现出典型的分子内电荷转移(ICT)和聚集诱导增强发射(AIEE). 该化合物可以作为荧光探针检测水溶液中的苦味酸(2,4,6-三硝基苯酚, TNP), 检出限为5.8×10^-7 mol/L. 作用机制为TNP的质子转移到Bis-Nph, 有效地阻断了其ICT发射, 使荧光发生显著猝灭. 另外, Bis-Nph的细胞毒性较低, 可做成试纸进行TNP的快速检测.     

Molecular Machines Working on Surfaces and at Interfaces

In the past ten years a great variety of artificial molecular machines have been constructed, and very interesting concepts for controlling molecular‐level movements by external inputs have been developed. Most of the studies, however, have been performed in solution, where the investigated systems contain a huge number of molecules which behave independently from one another because they cannot be addressed individually. Before such systems can find applications in many fields of technology, they must be interfaced with the macroscopic world by ordering them in some way so that they can behave coherently and can be addressed in space. The problem of obtaining ordered arrays of molecular machines can be addressed by a variety of techniques, which include deposition on surfaces, incorporation into polymers, organization at interfaces, and immobilization in membranes or porous materials. In the last few years, the development of scanning‐probe techniques has also enabled direct observation and manipulation of single molecular‐machine molecules on surfaces. Techniques of this kind have opened novel routes to the study of molecular machines, and have also contributed to better understanding the differences between movement at the macroscopic and molecular levels. This paper reviews some recent achievements in the field of molecular machines working on surfaces and at interfaces, as single molecules or ordered arrays. Hybrid natural–artificial machines are also discussed, and the working mechanism of some natural machines is illustrated for the purpose of comparison.     

外源信号物质对肉苁蓉种子萌发体的影响研究

肉苁蓉（Cistanche deserticola Y.C.Ma）是沙生根寄生植物。采用激光扫描共聚焦显微镜（LSCM）,对种子经外源信号物质氟草敏（Norflurazon）、2,6-二甲氧基对苯醌（DMBQ）处理后萌发产生的类胚根状体、初生吸器的细胞形态;Ca2＋浓度、囊泡运输的变化情况进行了观察研究。结果表明,肉苁蓉种子萌发产生的类胚根状体顶部的细胞为多面体,细胞小,排列紧密,内含物较多,中部大多为长方形薄壁细胞,内含物少;经DMBQ处理后类胚根状体细胞的钙离子浓度升高,囊泡运输加强。研究结果为揭示外源信号物质对肉苁蓉寄生影响提供了理论依据。     

Multiple resonance heteronuclear decoupling under MAS: dramatic increase of spectral resolution at moderate magnetic field and MAS frequencies

The effects of multiple-resonance heteronuclear decoupling under magic angle spinning (MAS) on the resolution of one-dimensional ¹⁹F and ³¹P and various two-dimensional MAS NMR spectra and on the residual non-refocusable coherence lifetimes in fluorinated aluminophosphate AlPO₄-CJ2, i.e. a compound that contains numerous highly abundant nuclei but no homonuclear spin bath, has been investigated. The design of the four-channel (¹H, ¹⁹F, ²⁷Al, ³¹P) MAS probe used for this study is first described. ¹H and ¹H–²⁷Al double-resonance decouplings allows lengthening the optimized transverse relaxation and increasing the resolution in the ¹⁹F and ³¹P dimensions. Under the application of multi-nuclear decoupling, a two-dimensional ¹⁹F–³¹P CP-HETCOR correlation spectrum for AlPO₄-CJ2 is recorded with unprecedented high-resolution in the two dimensions. Moreover, because ¹H-decoupling increases the ¹⁹F , it has been applied during the entire duration of the 2D NMR experiments, allowing the direct use of residual small interactions to generate ¹⁹F–¹⁹F and ¹⁹F–²⁷Al 2D NMR correlation spectra in AlPO₄-CJ2.     

若丹明类荧光探针的合成与应用研究进展

本文综述了近年来若丹明类荧光染料的研究状况.首先,介绍了若丹明衍生物的结构特征,然后以其修饰位置为线索,详细地介绍了该类化合物的合成,总结了其修饰策略及结构与功能之间的联系,强调了它们在环境分析和生物标记领域的应用.以供读者了解若丹明荧光探针的合成及其在蛋白质、DNA等生物标记领域和金属离子检测领域的应用时参考.     

一种增色检测铜离子的新型罗丹明B衍生物探针

合成了一种新型罗丹明B衍生物,(5-醛基吡咯-2-酸乙酯)罗丹明B酰肼西夫碱(RHPS)。在含30%乙腈的Tris-HCl缓冲溶液(pH=7.0)中,该探针本身无色,加入铜离子后溶液很快变为粉红色,而对其它金属离子如铁、汞、铅和镁等都没有明显响应。该探针与铜离子的结合是一个可逆过程,因此可应用于环境中铜离子的快速实时检测,线性范围为1.0×10-7～6.0×10-6mol/L,检出限达1.2×10-8mol/L。     

一种用于测定F~-的比色和荧光增强型探针

本文利用F~-诱导Si-O键断裂原理,以亚胺香豆素为荧光母体,成功合成了一种比色和荧光增强型F~-探针。由于探针分子结构的自由度较大,探针分子在乙腈溶液中几乎没有荧光,但随着F~-的加入探针分子经历Si-O键断裂及成环反应,生成具有较大共轭结构的环化产物,其荧光光谱在452nm处呈现出显著的荧光峰(荧光增强46倍),溶液的最大吸收峰由315nm红移至410nm(红移95nm),溶液的颜色由无色变为黄色,适用于裸眼检测F~-。同时,相对于其他阴离子(Cl~-、Br~-、I~-、NO_3~-、HSO_4~-、ClO_4~-、Ac~-、H_2PO_4~-),探针分子表现出对F~-较高的选择性和专一性,为F~-浓度的监测提供了一种高效灵敏的分析方法。     

The glucocorticoid derivative with the phthalimide group cationic nanocrystal for ophthalmic application: a design space development approach

The glucocorticoid derivative of budesonide with a phthalimide group is a drug candidate to treat inflammatory eye diseases; nevertheless, it presents low water solubility. Drug nanocrystals have been proposed to overcome this hurdle. The development of an innovative ophthalmic anti-inflammatory nanosuspension was performed using a design space approach. We obtained the particle size reduction of this glucocorticoid derivative on a nanometer scale (approximately 165.0 nm), applying wet bead milling on a super reduced scale. The design of experiment supported the optimization of the formula evaluating the parameters that influence reducing the particle size and also allowed determining the design space. Considering the two statistical models developed and the size range obtained, we proposed that the optimized formulation for the glucocorticoid derivative nanosuspension may be 1.0 wt% glucocorticoid derivative and 0.092 wt% cetylpyridinium chloride. This formulation was characterized by the morphological, physical–chemical, and mucoadhesive in vitro test and showed potential for ophthalmic use with reduced frequency of product application, improved efficiency, and safety, which may promote better patient compliance.     

氢离子辐照纯钒中形成的位错环

钒合金作为聚变堆候选材料, 其辐照损伤行为一直是关注的重点. 研究辐照时形成的位错环的性质, 其意义在于揭示纯钒中辐照空洞的长大机理. 这种机理表现为不同类型位错环对点缺陷吸收的偏压不同, 从而影响金属的辐照肿胀. 本文利用加速器对纯钒薄膜样品进行氢离子辐照, 然后, 利用透射电镜的inside-outside方法分析氢离子辐照所形成的位错环的类型. 结果表明, 在氢离子辐照纯钒中没有发现柏氏矢量b=<110>的位错环, 只有柏氏矢量b=1/2<111>和b=<110>的位错环, 这两种位错环的惯性面处于{110}-{112}之间. 能确定性质的位错环全部为间隙型位错环, 未发现空位型位错环.