Long-chain fatty ammonium quaternaries in papermaking

A series of long-chain quaternary ammonium halogen esters (UKK-chemicals), quaternary dimethyl tallow epoxypropyl ammonium halogens (EPK1), quaternary ditallow methyl epoxypropyl ammonium halogens (EPK2), and EPK2 oligomers (EPK2P) were synthesized. At acidic, neutral, or slightly basic conditions, EPK1-, EPK2-, EPK2P-, and UKK-chemicals operate as cationic chemicals. They can be used, for example, as stock sizings, surface sizings, or fixatives. Stock sizing, surface sizing, and fixative experiments indicate that EPK1-, EPK2-, EPK2P-, and UKK-chemicals function at least as well as or better than the corresponding synthetic chemicals used in papermaking.     

Direct measurement of the osmotic effects of buffers and fixatives in Nitella flexilis

The pressure probe has been used to investigate the amount and time course of changes in turgor induced by agents used in fixation of biological material for electron microscopy. All buffers tested decreased the turgor pressure of internodal cells of the green alga Nitella flexilis in proportion to their osmotic concentration. With the exception of s-collidine, the buffers were impermeant, as shown by the stability of the reduced turgor. The fixatives formaldehyde and glutaraldehyde caused a rapid reduction in turgor followed by recovery of turgor as the aldehyde penetrated the cell. Plasmolysis of cells can be avoided by a procedure involving stepwise increase of fixative concentration.     

Scanning electron microscopy of Streptomyces without use of any chemical fixatives

A new, short, and quick method was developed for preparation of specimen for observing Actinomycetes of genus Streptomyces by scanning electron microscopy. The cultures were directly grown on stubs and coated with a film of gold without using any fixative and dehydrating procedures. Using this simple preparation procedure, surface of intact sporing structures of Streptomyces was observed over a range of magnifications. As the preparation procedure is so simple and rapid, this procedure could be most useful for the routine examination and identification of Streptomyces.     

The role of primary alkanolamines in cosmetic formulation

Alkaline products are commonly used in cosmetic preparations as neutralizing agents for acid-functional raw materials. Primary alkanolamines can provide positive attributes in such cases. The properties of nitroparaffin-derived primary alkanolamines are compared here with the general requirements for cosmetic-type acid-neutralizing materials.
Acid-functional copolymers, used as hair fixatives in both aerosol and non-aerosol products, are efficiently solubilized by neutralization with 2-amino-2-methyl-1-propanol (amino-methylpropanol) in a variety of aqueous and non-aqueous systems. The effects of such neutralization on resultant film properties which influence product performance are discussed in detail.
Upon neutralization, crosslinked acrylic-acid polymers of varying molecular weights (carbomers) provide significant benefits when used as thickeners, gellants or emulsifiers in cosmetic products. New data are added to previous knowledge on the use of tris(hydroxymethyl)aminomethane (tromethamine) as a neutralizing agent for three resins, especially in gelled formulations. Alcohol compatibility, pH behaviour, and viscosity characteristics of such formulations are described. In addition, toxicological considerations of primary alkanolamines are addressed.
Further to the above applications, nitroparaffin-derived primary alkanolamines can be effectively used as cosmetic emulsifiers (in the form of their fatty-acid soaps), dispersants or co-dispersants for particulate-containing products, and pH buffers/stabilizers.     

半干鸡肉宠物食品的护色研究

利用异VC钠、柠檬酸、焦亚硫酸钠的单一与复配使用对半干鸡肉宠物食品进行护色研究。单一护色实验结果表明,护色效果焦亚硫酸钠>柠檬酸>异VC钠,复配护色实验表明柠檬酸能够增强异VC钠和焦亚硫酸钠的护色效果,柠檬酸:焦亚硫酸钠(质量比)=2:1时,对维持鸡肉宠物食品颜色金黄色,抑制的颜色加深变黑效果显著。     

嵌段共聚型固着剂的合成及其对溶解与胶体物质的聚集行为

利用可逆加成断裂链转移（RAFT）聚合法合成了一种新型的固着剂聚丙烯酰胺 b-聚二烯丙基二甲基氯化铵嵌段共聚物（P（AM-b-DADMAC）），通过傅里叶红外光谱（FT-IR）、核磁共振氢谱（1H-NMR）和体积排阻色谱(SEC)等检测手段对聚合物的结构进行了表征，并利用浊度法和聚焦光束反射测量仪（FBRM）考察了该聚合物对未漂热磨机械浆白水中溶解物质与胶体物质（DCS）的聚集行为。结果表明，采用RAFT方法可成功合成结构可控、分子质量分布较窄的嵌段共聚物P(AM-b-DADMAC)。与均聚物聚二烯丙基二甲基氯化铵（PDADMAC）相比，由于P(AM-b-DADMAC)具有特殊的化学结构和物理性质，其对溶解物质（DS）和胶体物质（CS）的处理效果均要好于PDADMAC。     

Techniques for reducing the interfering effects of autofluorescence in fluorescence microscopy: improved detection of sulphorhodamine B-labelled albumin in arterial tissue

Measurements of the transport of circulating sulphorhodamine B-labelled albumin into the arterial wall, made by applying digital imaging fluorescence microscopy to sections of arteries fixed in situ , are limited in sensitivity by the low levels of tracer fluorescence and high levels of autofluorescence emitted from the tissue. Three attempts to improve these ratios are described. In the first, spectra of the tracer in solution and of arterial autofluorescence were used to design novel microscope filters for rhodamine-like dyes. By exciting with the rarely used yellow lines of the mercury arc lamp and detecting a narrow band of emission with Stokes shifts as small as 15 nm, the ratio of tracer fluorescence to autofluorescence was tripled. In the second, effects of different fixatives were investigated. Using a model system, it was confirmed that Karnovsky's fixative gives good tracer immobilization but elevates autofluorescence, whereas fixative-free buffer solutions give low autofluorescence but do not retain the tracer. It was further found that simple formaldehyde-based fixatives, hitherto considered to be poor fixatives of albumin, immobilized the tracer as well as the glutaraldehyde-based fixative, whilst giving autofluorescence levels comparable to those seen with buffer alone; they therefore give excellent tracer fluorescence to autofluorescence ratios. In the third, lowering specimen temperature by 50 °C was found to increase the intensity of tracer fluorescence by 30% whilst autofluorescence was unaffected. These data may have relevance to microscopical studies using other tissues and fluorescent tracers.     

The potential of cryofixation and freeze substitution: observations and theoretical considerations

The theoretical and experimental evidence in favour of cryofixation and freeze-substitution are critically reviewed. The solubility of macromolecules in water is due to the hydration shells. Their behaviour at different temperatures and the consequences of their removal during the processing for embedding are explained. Gelation prior to the transfer into solvents prevents macromolecules aggregating. During substitution at low temperatures, DNA is gelled, justifying the use of the term cryofixation. It is proposed that the preservation of hydration shells at the lowest temperature, and their transformation into minute gaps after a rise of temperature, facilitates the exhibition of epitopes.     

Air-drying of human leucocytes for scanning electron microscopy using the GTGO procedure

The utilization of tannic acid and guanidine hydrochloride as mordants for better osmium binding has been shown to serve as an excellent alternative to metal coating of organ tissue specimens for scanning electron microscopy (SEM). The present report describes the GTGO procedure, a modification of the TAO technique introduced by Murakami et al. (1977, 1978), which we have found successful for the preparation of air dried peripheral blood leucocytes for SEM studies. Air dried, GTGO-treated leucocytes show excellent preservation of surface features with minimal cell shrinkage. When critical point dried, GTGO-treated cells are examined, they also show less shrinkage than cells prepared with standard glutaraldehyde fixation and critical point drying. The potential application of this air drying procedure (GTGO-AD) to other soft biological specimens is currently under investigation. This technique is recommended as a new and effective air drying procedure for the successful preparation of cells for SEM.     

Scanning electron microscopic observations on deembedded biological tissue sections: Comparison of different fixatives and embedding materials

Conventional plant histological specimens fixed in formalin-acetic acid-alcohol, chromic acid-acetic acid-formaldehyde, or glutaraldehyde-osmium and embedded in either paraffin or plastic are examined as possible rapid methods for providing an alternative image of cellular structure by using scanning electron microscopy. Using the mitotic figures of actively growing onion root tips as a study specimen, the organization of the nucleus and spindle apparatus is reasonably well preserved as compared with isolated mitotic spindles and studies of mitosis in endosperm tissue. Relief of internal structure in this technique is obtained through the coagulant nature of the fixative. Used judiciously, this technique can reveal aspects of the three-dimensional nature of internal tissue structure that may otherwise be difficult to discern.