TURBIDITY MEASUREMENTS AS A TECHNIQUE FOR EVALUATION OF WATER-IN-OIL EMULSION STABILITY

Stability of water-in-paraffinic oil (w/o) emulsions has been studied using turbidity measurements of diluted systems at 400 and 800 nm. The method has been found most suitable for detennination of the required HLB, amount and type of emulsifier, and the inner water phase fraction. The technique has been compared to other known methods and a good correlation was obtained.     

TRYPTOPHAN PHOSPHORESCENCE AT ROOM TEMPERATURE AS A TOOL TO STUDY PROTEIN STRUCTURE AND DYNAMICS

Fluorescence and phosphorescence resemble each other and in many ways can give the same type of information. Both originate from a dipolar interaction between light and the molecule. In this regard, both are polarized and subject to the same type of quenching phenomena. In other respects the information which they divulge are complementary. The fluorescence quantum yield is higher for exposed tryptophans and this is expressed in longer lifetime (Grinvald and Steinberg, 1976); in contrast long lifetime of phosphorescence appears to correlate with burial. Phosphorescence, spin-disallowed, is much longer lived than fluorescence. This allows the structural/dynamic characterization of proteins to be studied on a new time regime. A really remarkable finding of studies of protein phosphorescence is that there is such variability both in phosphorescence lifetime and quenchability. We would interpret this to indicate that the tryptophan environment can range from essentially a crystal, almost comparable in rigidity as found at 77 K, to tryptophans in a flexible environment, almost as flexible as free in solution. An interesting task will be to examine the relationship between the yield and lifetime of phosphorescence and details of the tryptophan environment in terms of rigidity and adjacent amino acids among the proteins with known three dimensional structure.     

甲基丙烯酸甲酯-甲基丙烯酸无规共聚物的合成及其在乳液聚合中的应用

通过自由基共聚制备了不同组成的甲基丙烯酸甲酯-甲基丙烯酸无规共聚物,用碱中和后作为大分子乳化剂用于乳液聚合.研究了无规共聚物的组成、用量及反应温度对乳液聚合的影响.结果表明,在相同的反应条件下,乳化剂中聚甲基丙烯酸含量越多,乳液聚合速率越快;同一乳化剂,随乳化剂浓度的增加,乳液聚合速率增加;在乳化剂组成、浓度不变的情况下,反应温度越高,乳液聚合速率越大.     

THE USE OF A COMPUTERIZED SPECTRORADIOMETER TO PREDICT PHYTOCHROME PHOTOEQUILIBRIA UNDER POLYCHROMATIC IRRADIATION

Abstract A method is described for predicting the effect of polychromatic irradiation upon the photo-stationary equilibrium of the plant photoreceptor phytochrome. This method follows from the rate equations for phototransformation and utilizes the in vivo action spectra for phytochrome phototransformation (Pratt and Briggs, 1966). A scanning spectroradiometer interfaced with a microcomputer is used to determine a spectral photon distribution from 360 to 800 nm. The products of the photon fluence rate and the relative quantum efficiencies at 2-nm intervals are summed over the entire visible range to yield a predicted percentage of the pigment in the Pfr form. This value was determined under eight different polychromatic light sources and was generally within 7% Pfr of the value measured in etiolated corn coleoptiles under the same light sources.     

岩相因子对煤的燃烧特性的预测

为了研究显微组分对煤及焦的燃烧特性的影响，从显微组分和煤阶的角度描述反应性能的变化。本文提出考虑显微组分和煤阶的岩相因子，较好的表示煤的类型和煤化程度对燃烧特性的影响，较前人孤立地看待显微组分和煤阶的影响量大进步。用岩相因子一煤的着火关，取得比较满意的结果。     

MASS TRANSPORT EFFECTS ON THE STABILITY OF EMULSION: EMULSION FILMS WITH ACETIC ACID AND ACETONE DIFFUSING ACROSS THE INTERFACE

The stability of emulsions is studied using, as a model of two interacting drops, an aqueous film of a surfactant immersed in an oil phase. It is shown that the mass transfer of a solute across the film changes its life-time. This change depends on several parameters as the nature and concentration of the solute. the direction of mass transfer, the time elapsed after the formation of the film. The destabilizing effect, of the transfer is found to be much less pronounced when the solute is in the continuous water phase. The instability is ascribed to the Marangoni effect and/or to liquid flow from the film drawn by diffusion of the solute.     

PHOTO-CIDNP AS A TOOL FOR THE STUDY OF THE REACTIVITY OF PHOTOSENSITIZING DRUGS: THE FUROCOUMARINS

Abstract— Several monofunctional and bifunctional furocoumarin derivatives were studied by means of the photo-CIDNP technique. Nuclear spin polarizations were observed on some of these derivatives when irradiated in acetonitrile solutions. The likely occurrence of both semi-reduced and semi-oxidized species of the FC in the reaction scheme is discussed.
When N-acetyltyrosine was added to the solution, CIDNP effects were observed on both reactants. They arose from a highly reversible pathway, as no photoproduct was polarized. On the FC part, the stronger effects were always observed on the 3,4 pyrone double bond suggesting that it must possess the highest spin density in the reaction intermediate. According to previous studies, the latter should be the FC anion or neutral radical. For the amino-acid moiety, the intensity of the polarizations was strongly dependent on the nature of the FC. This allowed the classification of the FC into three groups (zero, weak and strong intensities). As compared with their photobiological reactivity, this classification seemed to be related to the usual mono- and bifunctional distinction. This is the second example showing that photo-CIDNP could be used as a preliminary test for the study of the photosensitizing drug properties.     

INTRACELLULAR SH-LEVELS AS RELATED TO TUMOR PROBLEMS

Abstract

In the following review we will distinguish between non-protein thiols NPSH and protein thiols PSH. SH include low molecular SH-compounds such as glutathione, cysteine, SH containing coenzymes (such as coenzyme A, dihydrolipoic acid and glutathione). It cannot be the goal of this review to deal with the biochemical functions of CySH or the coenzymes which belong to elementary biochemistry.     

SURFACE METAL ION-IMPRINTED RESINS PREPARED BY EMULSIFIER-FREE EMULSION POLYMERIZATION USING PHOSPHORIC DIESTER AS FUNCTIONAL MONOMER

The uniform surface ion-imprinted resins for Zn2+ as the imprinting guest were prepared by emulsi fier-free emulsion polymerization utilizing ally phenyl hydrogenphosphate as a functional comonomer. The Zn2+-imprinted resin adsorbed Zn2+ much more effectively than did the unimprinted one. The selective feature of the surface imprinted resins to the template ions was demonstrated.     

SURFACE METAL ION-IMPRINTED RESINS PREPARED BY EMULSIFIER-FREE EMULSION POLYMERIZATION USING PHOSPHORIC DIESTER AS FUNCTIONAL MONOMER

1.INTRODUCTIONMolecularimprintingtechnique,asaconceptdemonstratedfirstlybyWuffandhiscoworker[1],hasrecentlyemergedasatechniquefordevelopingspecialrecognitionofvarioustargetmaterials[2~6].Theresultantimprintedpolymerscontainaspecificrecognitionsitethatcanrecognizetheimprintingmoleculeandhenceexhibitahighselectivityforrebindingtheimprintingmolecule.Therecognitionsitescanbetailor-madebycopolymerizationofcross-linkingmonomersandfunctionalmonomerswithwhichinteractatargetmolecule.However,mostof…     

11-钨过渡金属杂多阴离子为配体的配合物的热稳定性研究

通式为MW_(11)O_(39)的“不饱和”11-系列杂多阴离子仍然保持了基本的Keggin结构,但失去了其中的一个W-O基团。MW_(11)O_(39)具有很高的反应活性,当其他金属离子(或3A主族元素离子)进入这一空位时,便形成了三元杂多配合物ZMW_(11)和Ln(MW_(11))_2。ZMW_(11)(Z为3A主族金属离子和过渡金属离子)中,11-杂多阴离子起着五齿配体的作用,第六个配位位置被结构水占据,ZMW_(11)基本保持原来的Keggin结构。Ln(MW_(11))_2(Ln为镧系或锕系离子)     

EMULSION POLYMERIZATION AS A METHOD FOR THE DETERMINATION OF THE CRITICAL MICELLE CONCENTRATION OF SURFACTANTS OF LOW SOLUBILITY IN WATER +

Although a large number of methods are available for the determination of critical micelle concentrations many of these cannot be applied to the highest members of homologous series which are insufficiently soluble in water. The number of latex particles formed and consequently the rate of emulsion polymerization of such monomers as styrene which have only a very low solubility In water increase rapidly at the c.m.c. of the surfactant. When the surfactant is a salt which can be formed at the interface by dissolving the long-chain acid in the monomer and a slight excess of alkali in the water, observation of surfactant concentration at which this increase in particle number and polymerization rate takes place provides an experimental method for the determination of the c.m.c. which gives results in good agreement with expectation based on an extrapolation of results obtained by other methods on lower members of the series in the case of potassium docosanoate.     

REDUCTION OF TERMINAL ORGANYLCHALCOGENO PHOSPHONATES AS A WAY TO PREPARE PRIMARY ORGANYLCHALCOGENO PHOSPHINES

2-Organylseleno(telluro)ethyl phosphines and 4-organylthio(seleno (telluro))butyl phosphines were prepared by reduction of diethyl 2-organylseleno(telluro)ethyl phosphonates and diethyl 4-organylthio(seleno(telluro)) butyl phosphonates with lithium aluminium hydride in diethyl ether. ¹H and ³¹P NMR spectra as well as mass spectra of the resulting phosphines were considered. Their stability in regard to the oxidation by oxygen was discussed.     

METHYL SALICYLATE FLUORESCENCE AS A PROBE OF THE GEOMETRY OF COMPLEXATION TO CYCLODEXTRINS

Abstract Methyl salicylate (MS) is found to form complexes with α-, β- and γ-cyclodextrins in aqueous solution. The fluorescence of the complexes differ dramatically from that of MS in pure aqueous solution in the case of α- and γ-cyclodextrin, but is similar to that of MS in pure aqueous solution in the case of β-cyclodextrin. The binding constants for the complexes have been evaluated and the fluorescence of the complexes has been employed to infer the geometry of the complexes.     

团结奋斗开拓创新建设制造强国

放眼世界 ,随着经济全球化进程日益加快 ,新一轮的世界产业结构调整正在不断推进 ,国际分工正在更为宽广的领域展开。如何在全球经济格局中占据有利位置 ,如何应对高科技时代的激烈竞争 ,如何化解全球化这把双刃剑可能带来的损害 ,如何赢得未来世界对自己国家和民族的尊重 ,已经成为各国必须应答的命题。制造业 ,特别是装备制造业的整体能力和水平将决定各国的经济实力、国防实力、综合国力和在全球经济中的竞争与合作能力 ,决定着一个国家 ,特别是发展中国家实现现代化和民族复兴的进程。作为刚刚进入工业化中期的发展中国家 ,我们必须清醒…     

A study of PBT/PC blends by modulated DSC and conventional DSC

Two poly(butylene terephthalate)/polycarbonate (PBT/PC) blends with different formulations were analyzed by modulated DSC (MDSC) and conventional DSC to determine differences in crystallization behavior. A significant difference (30°C in cold crystallization temperature) between the two samples was detectable by MDSC while no significant difference was seen by conventional DSC. That indicatesthe total heat flow from MDSC is not always equivalent to the heat flow from conventional DSC as we have assumed or seen before. The reason has not been fully understood, but may be related to unusual nucleation and crystallization induced by modulation. Alternative conventional DSC methods were developed and compared to the MDSC results.Dedicated to Professor Bernhard Wunderlich on the occasion of his 65th birthdayThe authors like to thank Drs. Bernhard Wunderlich and Robert Gallucci for helpful discussion, David Shaker and Mary Parsonage for some DSC experiments. Technical support from TA Instruments is also greatly appreciated.