Sensitometric Study of the IAG Gelatins using the Rapid Emulsion Sensitometric Evaluator

Abstract

The influence of several alkaline processed IAG gelatins on the chemical sensitization of an ammoniacal silver bromo/iodide (AgBr/l) emulsion has been studied using the Rapid Emulsion Sensitometric Evaluator (RESE). Simple calcium effects on the thiosulphate chemical sensitization process were minimized by adjustment of calcium content prior to sensitization. Results of relative optimum ripening time and relative speed are discussed.     

乳液聚合合成单分散纳米级PMMA微球

采用乳液聚合法制备了单分散性聚甲基丙烯酸甲酯（PMMA）纳米微球,分析了聚合过程中不同单体滴加时间、不同表面活性剂用量、不同引发剂用量以及不同引发剂种类等因素对聚合体系中微球的粒径以及粒径分布的影响,研究表明,PMMA微球的粒径随单体滴加时间、表面活性剂用量、引发剂用量的增加而减小;采用AIBN引发剂制备的微球的粒径较采用KPS引发剂大。     

Monodisperse Emulsion Drop Microenvironments for Bacterial Biofilm Growth

In this work, microfluidic technology is used to rapidly create hundreds of thousands of monodisperse double and triple emulsion drops that serve as 3D microenvironments for the containment and growth of bacterial biofilms. The size of these drops, with diameters from tens to hundreds of micrometers, makes them amenable to rapid manipulation and analysis. This is demonstrated by using microscopy to visualize cellular differentiation of Bacillus subtilis biofilm communities within each drop and the bacterial biofilm microstructure. Biofilm growth is explored upon specific interfaces in double and triple emulsions and upon negative and positive radii of curvature. Biofilm attachment of matrix and flagella mutants is studied as well as biofilms of Pseudomonas aeruginosa. This is the first demonstration of biofilms grown in microscale emulsion drops, which serve as both templates and containers for biofilm growth and attachment. These microenvironments have the potential to transform existing high‐throughput screening methods for bacterial biofilms.     

乳液种子生长法制备亚微米单分散聚苯乙烯微球

采用乳液种子生长法设计生长500～600nm范围的单分散聚苯乙烯微球,研究了种子生长法中新核产生的条件,当乳化剂对苯乙烯磺酸钠浓度等于1.298mmol/L=CCMC/10时,不产生新核心.同时为避免单体自聚结块,采用多次投料的方法,成功制备单分散性良好的聚苯乙烯微球.     

反相乳液法制备单分散性Fe3O4微粒的研究

为制备单分散性的Fe3O4微粒,采用反相乳液法,以Fe2 与Fe3 按n(Fe2 ):n(Fe3 )=1:2配成的水溶液作为水相,十二烷基磺酸钠为乳化剂,液体石蜡和水溶液形成油包水型乳液,用NaOH共沉淀.实验考察了油/水体积比、搅拌速度、乳化剂及碱用量、乳化时间的影响.结果表明,较佳的条件是:在V(石蜡):V(水)=6:1,1030r/min的搅拌速度下,乳化剂的量为4.5g/L,乳化20min后,用超过理论用量5%的氢氧化钠共沉淀.用粒度仪和磁天平表征所得Fe3O4,数均粒径为2μm,98%的粒径分布在1～5μm,质量磁化率为2.60×10-2emu/g.     

快速彩纸氯化银立方晶体外延溴化银乳剂制备方法的研究

外延量在0—5个摩尔百分数范围研究其对氯化银立方晶体外延溴化银乳剂照相性能的影响,并探讨三种供快速彩纸用乳剂的制备途径。     

Possibilities for Chemical Characterization of Inert Gelatins

An overview is given of some chemical methods of characterization of photographic inert gelatins.

Some analytical methods are discussed and results given to show how much information can be obtained from chemical analysis regarding the photographic properties of inert gelatins.     

氧化还原引发无皂乳液聚合制备单分散热敏性微球

在可聚合乳化剂甲基丙烯磺酸钠存在下,以过硫酸钾和亚硫酸氢钠为氧化还原引发体系,将苯乙烯和N-异丙基丙烯酰胺进行无皂乳液聚合,制得粒径大小在200 nm~300 nm范围内的单分散热敏性聚(苯乙烯/甲基丙烯磺酸钠/N-异丙基丙烯酰胺)微球。通过透射电镜观察微球形态和大小,并采用激光光散射粒度仪考察微球粒径大小随温度变化情况。探讨了水溶性单体/油溶性单体比、引发剂用量等对微球粒径大小的影响。结果表明,制备的乳胶粒粒径在32℃附近明显减小,呈现出热敏性质;微球粒径随水溶性单体/油溶性单体比的增大而减小,随引发剂用量的增大而增大。     

Study of Sol Components in Photographic Gelatins

The sol components isolated from commercial photographic gelatins were quantified. A comparison of molecular behaviour between the separated sol portion and eel portion from one of the tested commercial gelatins was made. The sol components in the first, second, third and fourth run gelatins (1-4 extracts) were investigated and correlated with the extraction conditions and molecular behaviour. The effects of extraction temperature and extraction extent (specified by time), and the influences of the sol components on the physical properties, especially on the notification of the gelatins, were verified, and observed by specially designed experiments. The possible mechanism of the liquifying process is discussed on an experimental basis     

Studies on the Properties of Fractionated Gelatins

Gel permeation chromatography (CPC) and temperature solubility were used to isolate different molecular weight fractions of several photographic gelatins. The dependence of the amino acid composition of impurities and metal ion contents on molecular xveight was investigated. The lower molecular weight fraction had an unusual amino acid composition. The difference in amino acid composition was observed according to the raw material species, the methods of manufacture and those of fractionation. This lower molecular weight fraction contained more tyrosine, histidine, methionine, hydroxylysine and hydrophobic amino acids than the original gelatin, while it contained less lysine, alanine and acidic amino acids than the original gelatin. It was considered that the low molecular weight fraction contained a certain amount of telopeptide, peptide from the a2 (1) chain and non- collagenous proteins. High contents of iron and calcium ions as impurities were observed in higher and lower molecular weight fractions.     

偶氮二异丁基盐酸脒引发甲基丙烯酸甲酯微球的无皂乳液聚合

采用偶氮二异丁基盐酸脒(AMPMDHC)为引发剂,用无皂乳液聚合方法制备单分散性PMMA微球,合成粒径为500nm的单分散PMMA微球的聚合条件是:MMA/H2O=20:100(m1),温度为70℃,AMPMDHC用量为0.06g,反应时间为1.5h.实验结果表明:(1)引发剂用量越多,PMMA微球粒径越小,但对微球粒径分布影响较小;(2)反应温度升高,微球粒径增大,单分散性降低;(3)微球的粒径随着水的用量增大而降低,当MMA/H2O小于1/6时,微球粒径趋于180nm.     

小尺寸单分散铂纳米粒子的制备

为提高铂催化剂的催化活性,降低催化剂成本,在水/TX-4(壬基酚聚氧乙烯醚)/正丁醇/环己烷微乳液体系中成功制备了粒径2～4nm的单分散铂纳米粒子,并对其进行了TEM和EDS表征。微乳液体系的相图表明,Kw=5∶3,m(S-As)/m(O)=3∶2是制备小尺寸铂纳米粒子的最佳配比。H2PtCl6和NaBH4(过量时)浓度增大时,对产物粒径影响不大,但使粒径的均匀性降低;增溶水量ω增大,粒子粒径增大。CH2PtCl6≤25mmol·L-1,CNaBH4≥100mmol·L-1,ω≤2是制备小尺寸、单分散铂纳米粒子的关键,粒子尺寸可通过改变ω值调节。     

The Chemical Basis of Molecular Weight Differences in Gelatins

Abstract

The breakdown of intact collagen from bone or hide to produce commercial gelatin results in a poll/disperse product with respect to molecular weight. The mechanism of this breakdown and the role of the individual collagen chains in gel formation is not clearly understood.

Analysis of these polypeptide chains for molecular iveight and inter-chain cross-linking of both commercial gelatin and isolated intact components from purified collagen, and the ability of both to form gels, should provide data on the mode of breakdown and the mechanism of gel formation. We have shown that the isolated pure α and β-components form firm gels, in which a high proportion of triple helix Is generated. In contrast, the α2 chain forms weak gels and generates little helix. The highly cross-linked high molecular weight components also produce weak gels, yet generate a high proportion of triple helix. It is possible that the rapid production of triple helices by chains in register due to cross-linking actually reduces network formation, in which multiple chain interactions forming short helices is preferable.     

On the Level of Nucleic Acids in Bone Gelatins

It is shown that nucleic acids are present in bone and that these are largely removed in the acid de-mineralization step. Initial extraction of nucleic acid by mineral add is quite rapid and is probably followed by conversion to apurinic acid. When the bone is extracted without acid treatment, as in the preparation of bone glue, the product is very rich in nucleic acids of relatively low molecular weight. The acid treatment also extracts small amounts of a protein material which may be a restrainer     

Monodisperse breakup of liquid jets

The monodisperse breakup of liquid jets with various physical properties is investigated experimentally and theoretically over a wide range of jet breakup parameters.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 55, No. 3, pp. 413–418, September, 1988.     

超声波辅助制备单分散金属包覆聚苯乙烯导电微球

为了制备单分散聚合物基导电微球,以交联聚苯乙烯(PS)微球为基体,通过超声波辅助的化学镀方法制备了单分散Ni/PS导电微球,接着采用置换法在导电微球表面包覆一层导电性更好的Au层。采用FI-IR,SEM,EDS,XRD等测试方法分别对PS微球及导电微球的官能团变化、形貌、元素组成及晶型结构进行表征,结果表明:超声的引入可以改善导电微球的分散性;导电微球形貌规则,镀层连续均一且有纳米级"丘状"突起。经过金层包覆后导电微球的体电阻率可达到6.9×10-3Ω.cm,可以满足ACF中导电微球的使用要求。     

Laboratory-scale Test for Studying the Coagulation Behaviour of Chemically Modified Gelatins

It has long been recognized that the solubility and coagulation characteristics of chemically modified gelatins can be exploited by emulsion manufacturers for the purpose of washing and concentrating silver halide emulsions. In order to study these characteristics, it has generally been necessary to precipitate silver halide grains in the presence of the chemically modified gelatin to provide a substrate for the coagulation. A more convenient test system has been developed that uses a readily available material (barium sulphate) to mimic silver halide grains and provide a reproducible substrate for coagulation. This test system has been used to study various aspects of the coagulation process and their relationship to properties of phthalic anhydride (PA) modified gelatins. The coagulation properties (or solubilities) of PA gelatins were found to be a non-linear function of the degree of modification. Molecular weight distribution was found to be a secondary factor in solubility.     

单分散聚合物微球的合成技术

综述了单分散聚合物微球的制备方法和研究新进展,具体介绍了分散聚合法、种子聚合法,同时对一些特殊的单分散微球制备方法如SPG玻璃膜乳化法,微波、电离辐射诱导聚合法,气溶胶光聚合法进行了简要介绍,并对这些方法进行评述分析,可知前三种方法对环境污染小,为聚合物微球的工业化绿色生产提供可能.