DMCHA提取油脂中溶剂残留量的气相色谱分析研究

利用转极性溶剂提取油脂可减少环境污染、降低分离能耗。建立了转极性溶剂N,N-二甲基环己胺（DMCHA）在提取的麻疯树籽油中残留量的气相色谱分析方法。该方法采用安捷伦GC7890A气相色谱仪,FID检测器,DB-5HT毛细管柱,DMCHA与麻疯树籽油能实现良好分离,分析时间为14.3 min。DMCHA在0.4~2.0 g/L范围内,与峰面积存在良好的线性相关性,相关性系数为0.993,精密度实验中相对标准偏差为3.87%,加标回收率在99.18%~104.02%之间。该方法能够快速准确测定DMCHA提取的麻疯树籽油中溶剂残留量。

溶剂对普拉格雷硫酸氢盐晶型转变过程的影响机制

目的:为了确定普拉格雷硫酸氢盐多晶型体系的稳定性关系,阐明溶剂对其多晶型成核的影响规律,并揭示普拉格雷硫酸氢盐的转晶机制。方法:本文以普拉格雷硫酸氢盐晶型Ⅰ和晶型Ⅱ为研究对象,聚焦其溶剂介导的转晶过程,离线监测了转晶过程中悬浮固相的晶型组成和溶液浓度随时间的变化趋势,并揭示溶剂对其晶型转变过程的影响机制。结果:通过X-射线衍射法测定了普拉格雷硫酸氢盐Ⅰ晶型向Ⅱ晶型的溶剂介导转晶过程,结果表明该转晶过程的速率控制步骤为普拉格雷硫酸氢盐Ⅱ晶型的成核与生长。结论:综合考虑普拉格雷硫酸氢盐在丁酮、乙酸甲酯、甲基异丁基甲酮3种溶剂的转晶速率以及Ⅱ晶型在3种溶剂中的溶解度关系可知,普拉格雷硫酸氢盐Ⅱ晶型的成核过程除了受到溶解度的影响,还与普拉格雷硫酸氢盐分子和溶剂分子间氢键的强弱有关。

DBU/CH_3OH/CO_2(DCC)在甲醇、甲酯、甘油中的溶解度研究

1,8-二氮杂双环[5.4.0]十一碳-7-烯(DBU)作为一种转极性溶剂可应用在生物柴油生产工艺中,实现油脂萃取、酯交换反应、产物分离的耦合。本文就新工艺中涉及到的离子化合物DBU/CH3OH/CO2(DCC)的基本物性进行了研究,为新工艺的设计提供基础数据。首先用新方法合成了DCC纯离子化合物,然后利用平衡法研究了此物质在25℃、35℃、45℃在甲醇、甲酯、甘油中的溶解度及电导率、密度、粘度。结果表明,此离子化合物在甲酯中的溶解度仅为甲醇、甘油中的千分之一左右,25℃、35℃、45℃时在甲酯中的溶解度分别为:2.4848g/kg、5.2613g/kg、8.0318g/kg;在甲醇中的溶解度分别为:2.8194g/g、3.5704g/g、4.2439g/g;在甘油中的溶解度分别为:2.8704g/g、3.5419g/g、3.8231g/g。溶解度均随温度升高而升高,电导率除离子化合物在甲酯中为零,其他均随温度升高而升高,密度及粘度随温度升高而下降。

Solvent-Induced Symmetry-Breaking Charge Transfer in an Octupolar Triphenylamine Derivative Resolved with Transient Fluorescence Spectroscopy

The excited-state symmetry-breaking charge transfer (SBCT) dynamics in quadrupolar or octupolar molecules without clear infrared markers is usually hard to be tracked directly. In this work, on the basis of the evolution of instantaneous emission dipole moment obtained by femtosecond transient fluorescence spectroscopy, we presented a real-time characterization of the solvent-induced SBCT dynamics in an octupolar triphenylamine derivative. While the emission dipole moment of the octupolar trimer in weakly polar toluene changes little during the excited-state relaxation, it exhibits a fast reduction in a few picoseconds in strongly polar tetrahydrofuran. In comparison with the uorescence dynamics of dipolar monomer, we deduced that the emitting state of the octupolar trimer in strongly polar solvent, which undergoes solvent-induced structural uctuation, changes from exciton-coupled octupolar to excitation localized dipolar symmetry. In weakly polar solvent, the octupolar symmetry of the trimer is largely preserved during the solvation stabilization.

Phosphorescent Cationic Iridium（Ⅲ） Complexes with 1,3,4-Oxadiazole Cyclometalating Ligands： Solvent-Dependent Excited-State Dynamics

To elucidate the nature of low-lying triplet states and the effect of ligand modifica- tions on the excited-state properties of functional cationic iridium complexes, the solvent- dependent excited-state dynamics of two phosphorescent cationic iridium（Ⅲ） complexes, namely [Ir（dph-oxd）2（bpy）]PF6 （1） and [Ir（dph-oxd）2（pzpy）]Pf6 （2）, were investigated by femtosecond and nanosecond transient absorption spectroscopy. Upon photoexcitation to the metal-to-ligand charge-transfer （MLCT） states, the excited-state dynamics shows a rapid process （τ-=0.7-3 ps） for the formation of solvent stabilized 3MLCT states, which significantly depends on the solvent polarity for both 1 and 2. Sequentially, a relatively slow process assigned to the vibrational cooling/geometrical relaxation and a long-lived phospho- rescent emissive state is identified. Due to the different excited-state electronic structures regulated by ancillary ligands, the solvation-induced stabilization of the 3MLCT state in 1 is faster than that in 2. The present results provide a better sight of excited-state relaxation dynamics of ligand-related iridium（Ⅲ） complexes and solvation effects on triplet manifolds.

Solvent Reorganization Energy and Electronic Coupling for Intramolecular Electron Transfer in BiphenyI-Acceptor Anion Radicals

A novel algorithm was designed and implemented to realize the numerical calculation of the solvent reorganization energy for electron transfer reactions, on the basis of nonequilibrium solvation theory and the dielectric polarizable continuum model. Applying the procedure to the well-investigated intramoleeular electron transfer in biphenyl-androstane-naphthyl and biphenyl-androstane-phenanthryl systems, the numerical results of solvent reorganization energy were determined to be around 60 k J/mol, in good agreement with experimental data. Koopman＇s theorem was adopted for the calculation of the electron transfer coupling element, associated with the linear reaction coordinate approximation. The values for this quantity obtained are acceptable when compared with experimental results.

Recent Progress on Biocatalysis and Biotransformations in Ionic Liquids

Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liquids or aqueous-ionic liquid biphasic systems. Up to date, there have been many reports on enzyme-exhibited features and enzyme-mediated reactions in ionic liquids. In many cases, remarkable results with respect to yield, catalytic activity, stability and (enantio-, regio-) selectivity were obtained in ionic liquids in comparison with those observed in conventional media. Accordingly, ionic liquids provide new possibilities for the application of new type of solvent in biocatalytic reactions.

Over-expression of uPA increases risk of liver injury in pAAV-HBV transfected mice

AIM:To investigate the relationship between overexpression of urokinase plasminogen activator(uPA) and hepatitis B virus(HBV) related liver diseases in a transgenic mouse model.METHODS:Albumin-tetracycline reverse transcriptional activator and tetO-uPA transgenic mice were generated respectively through pronuclear injection and crossed to produce the double transgenic in-alb-uPA mice,for which doxycycline(Dox)-inducible and liver-specific over-expression of uPA can be achieved.Hydrodynamic transfection of plasmid adeno-associated virus(AAV)1.3HBV was performed through the tail veins of the Dox-induced in-alb-uPA mice.Expression of uPA and HBV antigens were analyzed through double-staining immunohistochemical assay.Cytokine production was detected by enzyme linked immunosorbent assay and α-fetoprotein(AFP) mRNA level was evaluated through real-time quantitative polymerase chain reaction.RESULTS:Plasmid AAV-1.3HBV hydrodynamic transfection in Dox-induced transgenic mice not only resulted in severe liver injury with hepatocarcinoma-like histological changes and hepatic AFP production,but also showed an increased serum level of HBV antigens and cytokines like interleukin-6 and tumor necrosis factor-α,compared with the control group.CONCLUSION:Over-expression of uPA plays a synergistic role in the development of liver injury,inflammation and regeneration during acute HBV infection.

A novel animal model for in vivo study of liver cancer metastasis

AIM:To establish an animal model with human hepatocyte-repopulated liver for the study of liver cancer metastasis.METHODS:Cell transplantation into mouse livers was conducted using alpha-fetoprotein(AFP)-producing hu-man gastric cancer cells(h-GCCs) and h-hepatocytes as donor cells in a transgenic mouse line expressing urokinase-type plasminogen activator(uPA) driven by the albumin enhancer/promoter crossed with a severe combined immunodeficient(SCID) mouse line(uPA/SCID mice).Host mice were divided into two groups(A and B).Group A mice were transplanted with h-GCCs alone,and group B mice were transplanted with h-GCCs and h-hepatocytes together.The replacement index(RI),which is the ratio of transplanted h-GCCs and h-hepatocytes that occupy the examined area of a histological section,was estimated by measuring h-AFP and h-albumin concentrations in sera,respectively,as well as by immunohistochemical analyses of h-AFP and human cytokeratin 18 in histological sections.RESULTS:The h-GCCs successfully engrafted,repopulated,and colonized the livers of mice in group A(RI = 22.0% ± 2.6%).These mice had moderately differentiated adenocarcinomatous lesions with disrupted glandular structures,which is a characteristics feature of gastric cancers.The serum h-AFP level reached 211.0 ± 142.2 g/mL(range,7.1-324.2 g/mL).In group B mice,the h-GCCs and h-hepatocytes independently engrafted,repopulated the host liver,and developed colonies(RI = 12.0% ± 6.8% and 66.0% ± 12.3%,respectively).h-GCC colonies also showed typical adenocarcinomatous glandular structures around the h-hepatocyte-colonies.These mice survived for the full 56 day-study and did not exhibit any metastasis of h-GCCs in the extrahepatic regions during the observational period.The mice with an h-hepatocyte-repopulated liver possessed metastasized h-GCCs and therefore could be a useful humanized liver animal model for studying liver cancer metastasis in vivo.CONCLUSION:A novel animal model of human liver cancer metastasis was established using the uPA/SCID mouse line.This model could be useful for in vivo testing of anti-cancer drugs and for studying the mechanisms of human liver cancer metastasis.

Solvent Effects on Two-Photon Absorption of Alkyne and Alkene π-bridging Chromophores

The present work concerns the study of solvent effects on the geometrical structures, as well as one- and two-photon absorption （TPA） processes, for two series of alkyne and alkene π-bridging molecules, within the framework of the polarization continuum model. Particular emphasis was put on the characterization of solvent effects on the molecular geometrical structures and geometric distortion, which were measured by the bond-length-alternation parameter. The π centres in the compounds are seen to play a decisive role in increasing the TPA cross section and nonlinear optical properties. All studied molecules have relatively strong TPA characteristics, while the alkyne π-bridging ones yield larger TPA cross sections.

Solvent Dependence of Photophysical and Photochemical Behaviors of Thioxanthen-9-one

The photophysical and photochemical behaviors of thioxanthen-9-one(TX)in different solvents have been studied using nanosecond transient absorption spectroscopy.A unique absorption of the triplet state^(3)TX^(∗) is observed,which involves two components,^(3)nπ^(∗) and^(3)ππ^(∗) states.The ^(3)ππ^(∗) component contributes more to the^(3)TX^(∗) when increasing the solvent polarity.The self-quenching rate constant ksq of^(3)TX^(∗)is decreased in the order of CH_(3)CN,CH_(3)CN/CH_(3)OH(1:1),and CH_(3)CN/H_(2)O(1:1),which might be caused by the exciplex formed from hydrogen bond interaction.In the presence of diphenylamine(DPA),the quenching of^(3)TX^(∗)happens efficiently via electron transfer,producing the TX^(⋅−) anion and DPA^(⋅+) cation radicals.Because of insignificant solvent effects on the electron transfer,the electron affinity of the ^(3)nπ^(∗) state is proved to be approximately equal to that of the ^(3)ππ^(∗) state.However,a solvent dependence is found in the dynamic decay of TX^(⋅−) anion radical.In the strongly acid aqueous acetonitrile(pH=3.0),a dynamic equilibrium between protonated and unprotonated TX is definitely observed.Once photolysis,^(3)TXH^(+∗) is produced,which contributes to the new band at 520 nm.

Effects of Surfactant on Solubility and Microbial Conversion of Steroid

Enhancing the dispersion and dissolution of substrate particles in substrate water suspension is a feasible way to improve steroid bioconversion. The aim of the present study is to investigate the effects of applying surfactant to microbial conversion system on the dispersion, solubilization and in turn bioconversion of steroid substrate. The model system is hydroxylation of substrate 19α- 17α-epoxy- 4-pregnene- 3.2It-dine by microbial enzymes from Rhizopus nigricanl. The results show that the presence of substrate leads to an increase in critical micelle concentration （ CMC） of surfactant PSE compared with the normal CMC of PSE in aqueous solution. The grinding time during substrate suspension preparation affects the substrate aqueous solubility differently with the varied surfactant concentrations while barely making any difference in substrate solubility in the absence of surfactant. The properly prolonged grinding time can make up for the loss in substrate solubility arising from the reduction in surfactant concentration. The surfactant complexes composed of surfactants PSE and MGE at appropriate ratios are screened out with orthodoxy experiment method. the interaction between PSE and MGE exerts the most prominent effects on substrate bioconversion, and the surfactant complexes show more beneficial effects on steroid bioconversion than the surfactant PSE used alone.

ZnO hierarchical aggregates： Solvothermal synthesis and application in dye-sensitized solar cells

ZnO hierarchical aggregates have been successfully synthesized by solvothermal methods through reaction of zinc acetate and potassium hydroxide in methanol solution. The shapes of the aggregates were controlled by varying the ratio of Zn2~ and OH- ions in the reaction system, while the size can be tuned from 2μm to 100 nm. Oriented attachment was found to be the main mechanism of the three-dimensional assembly of small ZnO nanocrystallites into large aggregates. The performance of these aggregates in dye-sensitized solar cells （DSCs） indicated that hierarchical structured photoelectrodes can increase energy conversion efficiency of DSCs effectively when the sizes of aggregates match the wavelengths of visible light.

Statistical and thermodynamic properties of binary self-condensing vinyl polymerization

The thermodynamic properties of a binary self-condensing vinyl polymerization system consisting of monomers and inimers are investigated by the principle of statistical mechanics.In detail,in terms of two types of canonical partition functions constructed from different viewpoints,the equilibrium free energy,the law of mass action and the size distribution of hyperbranched polymers are obtained.As an application,the specific heat,equation of state and isothermal compressibility concerning the polymerization are given as well.To study the dimension of hyperbranched polymers in the system,a recursion formula satisfied by the(k+1)-th and k-th mean square radius of gyration is derived,and then the first,second and third radius of gyration under different solvent conditions are presented.The influences of the fraction of inimers,the conversion of vinyl groups and the solvent effect on the average dimension of hyperbranched polymers are discussed.

Effects of surfactants on enzyme-containing reversed micellar system

With the development of colloid interface and enzyme technologies,enzyme-containing reversed micellar system has been receiving much attention in bioseparation and bioconversion. Because of its high efficiency,it has brought new opportunities for the development of molecular biotechnology. Reversed micelles represent nano-sized aqueous droplets stabilized by surfactant amphiphiles inside the bulk organic solvents. The entrapped enzymes have enhanced activities under those conditions as suited in the lipid bilayers of biological membranes. The fundamentals of enzyme-containing reversed micellar system are described in this paper,with special emphasis on the effects of surfactants varying in concentrations and structures. The latest study progress on the surfactants application in enzyme-containing reversed micelles is reviewed. The introduction of novel functional surfactants in micellar enzymology and their future development are also discussed.

Elucidating the dynamics of solvent engineering for perovskite solar cells

Researchers working in the field of photovoltaic are exploring novel materials for the efficient solar energy conversion.The prime objective of the discovery of every novel photovoltaic material is to achieve more energy yield with easy fabrication process and less production cost features.Perovskite solar cells (PSCs)delivering the highest efficiency in the passing years with different stoichiometry and fabrication modification have made this technology a potent candidate for future energy conversion materials.Till now,many studies have shown that the quality of active layer morphology,to a great extent,determines the performance of PSCs.The current and potential techniques of solvent engineering for good active layer morphology are mainly debated using primary solvent,co-solvent (Lewis acid-base adduct approach)and solvent additives.In this review,the dynamics of numerously reported solvents on the morphological characteristics of PSCs active layer are discussed in detail.The intention is to get a clear understanding of solvent engineering induced modifications on active layer morphology in PSC devices via different crystallization routes.At last,an attempt is made to draw a framework based on different solvent coordination properties to make it easy for screening the potent solvent contender for desired PSCs precursor for a better and feasible device.

Up/down conversion luminescence rare-earth ion-doped Y_2O_3 1D nanocrystals

Multicolor luminescent rare-earth ion-doped Y2O3 nanocrystals （NCs） were prepared by a solvethermal method. The as-synthesized NCs yielded nanosheets, nanowires （NWs） and nanorods （NRs） with the increase of alkali （NaOH） in oleic acid system. Moreover, Y203 nanowires with controllable size have also been obtained. After sintering, the PL intensity of Y2O3：Ln3＋ nanocrystals increased with the changed morphology of the precursor, that is, Y（OH）3 nanocrystals. Both downconversion （red emission for Y2O3：Eu3＋ and green emission for Y2O3：Tb3＋） and upconversion （red emission for Y2O3：Yb/Er3＋） luminescence of the as-prepared nanocrystals have been demonstrated in this work. We also found that the PL intensity of Y2O3：Ln3＋ NCs dispersed in polar solvent was stronger than that in nonpolar solvent. Their up/downconversion fluorescence and controllable morphology might promise further fundamental research and biochemistry such as nanoscale optoelectronics, nanolasers, and ultrasensitive multicolor biolables.