This review describes the synthesis, the properties, and the functions of some cyclodextrin derivatives. Cyclodextrins are cylindrical molecules and well known to form host-guest complexes, but they are not amphiphilic molecules. Specific modification of primary and secondary hydroxyl groups transforms cyclodextrins into some water soluble surfactants or lipophilic derivatives soluble in organic solvents such as chloroform. Certain lipophilic derivatives form well-defined monolayers at water-air interface and multilayers as Langmuir-Blodgett films on solid plates. Characteristic feature of these derivatives is to form specific host-guest complexes. Complexation occures in surfactant aggregates as well as in monolayer or multilayer membranes.
Gel electrophoresis and gel chromatography in the presence of sodium dodecyl sulfate (SDS) are now widely used in the field of biochemistry for separation and analysis of proteins. Replacement of the sodium of SDS by lithium allows efficient separation of protein polypeptides in denatured state at 0°C. On the other hand, the replacement by Tris and several alkanolamines allows electrophoresis and gel chromatography at a temperature near 0°C of proteins retaining their native states. Derivatives of SDS having oligo (oxyethylene) chain between the dodecyl and sulfate groups are also promising as mild surfactants which can be used for the same purpose as above.
Current experimental techniques for estimation of the cell surface tension by contact angle measurements were reviewed. It is shown that in the process of measuring the contact angles of drops of water or air bubbles at biological surfaces, transfer of natural surface active materials to the air/water interface occurs with a consequent reduction in the surface tension. The estimation of cell surface tensions from contact angles based on theoretical calculations in which the air/water tension of pure water is used are in error. The adhering bubble method is preferable for contact angle determinations in biological systems.
We previously reported a potentiometric titration method which permits detection of very small amounts of hydroperoxides present in serum lipids. In the present work, lipid peroxide levels were determined by potentiometry in sera from about 400 subjects over 65 years old. The correlation of lipid peroxide levels with ageing was studied by comparing the levels of aged people with those of healthy young persons in their 20's or middle aged people in their 40's or 50's. The average serum lipid peroxide level of persons in their 40's was found to be 40.4±20.8 neq/mL, the highest of all male groups, decreased in proportion to the age of persons older than this. All female groups showed similar levels (ca. 26 neq/mL) independent of age. The specific values for the 40's group calculated as peroxide levels per 1 g of serum lipids exceeded those of other groups for both sexes, and were noted to decrease with ageing. Moreover, judging from the health conditions of subjects over 65 years old, the serum lipid peroxide levels of the cerebrovascular group appeared higher than those of the normal human group with significant difference. Since the subjects of typical geratic diseases surveyed in the present study were outpatients afflicted with mild forms of disease, further investigation should be conducted on patients of seriously afflicted to determine the correlation of serum lipid peroxide levels with various diseases.
The solidification behavior of cocoa butter from the melt phase was examined during two different types of thermal treatment : simple cooling (60→29°C) and cooling/heating (60→22→30°C).Triacylglycerol composition and polymorphic modified samples were determined. The crystals formed by simple cooling were a mixture of Form V and Form VI of cocoa butter. But only the Form V could be found in crystals obtained by the cooling/heating. These crystals were filtered out and what appeared to be fat blooming of the solidified samples of residual melt was examined. The fat blooming was found in solidified fat after the filtration of simple cooling crystals less than 1 μm in size and in cooling/heating cystals 0.22 μm in size. The addition of 0.2 % of the seed crystals of cocoa butter with Form VI increased the rates of solidification and no fat blooming was observed.
The viscosity B coefficients, heats of solution and surface activity of straigt chain α-amino acids H (CH2) n-1CH (NH2) COOH (Cn, n=15) in water were measured. The viscosity B coefficient of C1, increased with temperature, while those of C2 and higher homologs decreased with increase in temperature. Changes in heat capacity for dissolution in water, ΔC0p, as calculated from heats of solution at 15, 25, and 35°C, were negative for C1, white ΔC0p values for C2 and higher homologs were positive. C1, and C2 raised the surface tension of water, while C3 and higher homologs reduced it. Based on these results, structural changes in water as solvent with dissolution of α-amino acids and the effects of hydrophobicity of α-amino acids on surface active properties are discussed.
A series of novel amphiphilic monoazacrown ethers (1 a-n) have easily been prepared in high yields by addition reaction of monoaza-15-crown-5 and -18-crown-6 to homologous 1, 2-epoxyalkanes and alkyl glycidyl ethers in methanol. They were examined for cloud point and critical micelle concentration in aqueous solution, complexing stability constants with alkali metal cations in methanol and phase-transfer catalysis on Finkelstein reaction. The hydrophilicity and cation-complexing ability of N-alkylmonoazacrown ethers was progressively enhanced by introducing a β-hydroxyl group and the additional insertion of ether oxygen into the alkyl side chain. In spite of their great hydrophilicity, the crown ethers (1) with 18-membered ring had high phase-transfer catalytic efficiency which was superior to that of dicyclohexano-18-crown-6 (3) and similar to that of N-dodecylmonoaza-18-crown-6 (2 b), indicating that the excellent catalysis of (1) to be due to cation-complexation ability.
The rate equation for fatty soil removal as given below is based on the assumption that the cleaning process consists of the following two processes : (1) Removal of the first order, depending on initial concentration of soil in fabrics (Process 1). (2) Reversible soil removal and redeposition of removed soil (Process 2). At =a1exp (-k1t) +a2exp [- (k2-k-2) t]. where At is the absorbance corresponding to soil concentration in fabrics at time t, k1, and k2 rate constants of soil removal during processes 1 and 2 respectively, and k2, the rate constant for the redeposition of removed soil. The experimental results on model soil removal (fatty acid) from fabrics by SDS indicated the present treatment to be adequate. Soil removal in both processes was confirmed to be essentially the same in the case of fatty soil. The dependence of the rate constants and removal rate on temperature indicates the formation of liquid crystalline phases played to possibly be important to fatty soil detergent action.
9-Oxo-trans-2-decenoic acid (9) [Queen substance] and 10-hydroxy-trans-2-decenoic acid (17) [Royal jelly], both sex pheromones of the Apis mellifera were synthesized. The starting material which contained 3-acetyl-1-propanol, 3-chloro-1-propanol and 6-bromo-hexanoic acid was processed by relatively simple procedures such as dehydrogenation, Grignard reaction, hydrogenation, lithium aluminium hydride reduction, malonic acid condensation to produce sex pheromones (9) and (17) in yields of 2538%. The reaction products were identified by comparing their IR and 1H-NMR spectra with those of authentic samples.