Cubic phases of binary systems of 4'-n-tetradecyloxy-3'-nitrobiphenyl-4-carboxylic acid (ANBC-14)-n-alkane

The phase behaviour of the binary systems 4'-ⁿ-tetradecyloxy-3'-nitrobiphenyl-4-carboxylic acid (ANBC-14)-ⁿ-alkane (ⁿ-tetradecane or ⁿ-hexadecane) was investigated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. The phase behaviour was a function of temperature (^T) and the effective carbon number of the system (^n*), where ^n* involves carbon atoms both from the alkoxy group of ANBC-14 and from the ⁿ-alkane added. ANBC-14 shows no cubic phase, but the addition of ⁿ-alkane induced cubic phases when ^n*≧c. 15. An interesting point is that the type of cubic phase is ^Ia3^d for 15^≦n*≦17, while an ^Im3^m type is formed for 18^≦n*≦20. Furthermore, for ^n* = 22, two types of cubic phase, one with ^Im3^m symmetry in the low temperature region and the other with ^Ia3^d in the high temperature region, were observed both on heating and cooling. The phase diagram with respect to ^T and ^n* is very similar to that of pure one-component ANBC-ⁿ, which is a function of ^T and the number of carbon atoms in the alkoxy group ⁿ.     

Variational principle for regular and random Ising models on the cactus tree or on the usual lattice in the “cactus approximation”

The distribution functions and the free energy are expressed in terms of the effective fields for the regular and random Ising models of an arbitrary spin S on the generalized cactus tree. The same expressions apply to systems on the usual lattice in the “cactus approximation” in the cluster variation method. For an ensemble of random Ising models of an arbitrary spin S on the generalized cactus tree, the equation for the probability distribution function of the effective fields is set up and the averaged free energy is expressed in terms of the probability distribution. The same expressions apply to the system on the usual lattice in the “cactus approximation”. We discuss the quantities on the usual lattice when the system or the ensemble of random systems has the translational symmetry. Variational properties of the free energy for a system and of the averaged free energy for an ensemble of random systems are noted. The “cactus approximations” are applicable to the Heisenberg model as well as to the Ising model of an arbitrary spin, and to ensembles of random systems of these models.     

Studies on proton pump inhibitors. II. Synthesis and antiulcer activity of 8-[(2-benzimidazolyl)sulfinylmethyl]-1,2,3,4-tetrahydroquinolines and related compounds

Many 8-[(2-benzimidazolyl)sulfinylmethyl]-1,2,3,4-tetrahydroquinolin e derivatives were synthesized and tested for their (H+ + K+)adenosine triphosphatase (ATPase)-inhibitory and antisecretory activities against histamine-induced gastric acid secretion in rats. These sulfinyl compounds were synthesized by the oxidation of the corresponding sulfides, which were obtained from the reaction of 8-chloromethyl-1,2,3,4-tetrahydroquinolines and 2-mercaptobenzimidazoles in the presence of potassium carbonate. All compounds tested were potent inhibitors of (H+ + K+)ATPase. Most of the compounds showed antisecretory activity. Among them, 8-[(2-benzimidazolyl)sulfinylmethyl]-1-ethyl-1,2,3,4-tetrahydro quinoline (IXa) was found to have the most potent activity. The structure-activity relationships are discussed.     

Simple and rapid extraction method of total egg lipids for determining organochlorine pesticides in the egg

A simple and rapid extraction method of total egg lipids for determination of organochlorine pesticides (OCPs) in the egg was developed. After being mixed with anhydrous sodium sulphate, the extraction of lipids in egg yolk was performed using n-hexane–acetonitrile (2:1, v/v). Troublesome emulsions did not occur. Using the present method, an average of 3.03 g of egg lipids was collected from 10 g of egg yolk. Compared with classical methods, the present method is handy; needs much shorter analysis time and less requirement of solvents and has higher efficiency of egg lipid extraction and higher recoveries of OCPs.