Comparative study of metomega chrome blue BBL, calcon, eriochrome blue S.E. and omega chrome black blue G as indicators in the complexometric titration of calcium and magnesium

Conclusion It can be concluded that for the determination of calcium and magnesium in mixtures two separate titrations are to be done in case of Calcon, Erio SE, BBG. Total calcium and magnesium was determined first and then calcium in a separate titration. Magnesium is found by differences whereas in the case of BBL, the mixture was first titrated for its calcium content, then the solution is made acidic with hydrochloric acid and then alkaline with ammonia buffer solution pH 10 and magnesium is determined in the same sample.It is also noticed that Erio SE can work in sodium hydroxide or potassium hydroxid medium as well as in diethyl amine; but its drawback is the red hue which can be overcome by the addition of a green component, whereas BBL is spoilt in sodium hydroxide or potassium hydroxide medium.In comparing the first 3 indicators (Calcon, Erio SE, BBG) we find that BBG is the best one in the titration of calcium and magnesium using either EDTA on Complexion IV, and its endpoint has no red hue as that found in Erio SE; also the recovery of calcium is quantitative in any ratio of magnesium.

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Vergleichende Untersuchung von Metomega Chromblau BBL, Calcon, EriochromblauS.E.und Omega-ChromschwarzblauG als Inidicatoren bei der komplexometrischen Bestimmung von Calcium und Magnesium

     

Studies on arylhydrazonoisoxazolinethiones. Behaviour of 4-arylhydrazono-3-phenyl-2-isoxazoline-5-thiones toward hydrazines,grignard reagents and alkylating agents

The 4-arylhydrazono-3-phenyl-2-isoxazoline-5-thiones 2 react with hydrazines to yield the 5-hydrazones 3 and 5 . The reaction of 2 with Grignard reagent resulted in addition of the reagent to the thiocarbonyl group to yield 7 . Treatment of 2 with diazomethane effected S - and N -methylation beside 1,2,3-triazole derivative 11 obtained through isomerisation. The potassium salt of 2 react with alkyl halides to yield the S-alkyl derivatives 12 .     

Determination of antihypertensive mixtures by use of a chemometrics-assisted spectrophotometric method

A simple multivariate calibration method for analysis of two types of hypotensive mixture is described. The mixtures are composed of chlorthalidone with atenolol or chlorthalidone with both amiloride hydrochloride and atenolol. The components of the mixtures result in substantial spectral overlap—between 87.5 and 91.0%. Resolution of the mixtures under investigation has been accomplished mainly by using CLS and PCR methods. The components in each mixture have been simultaneously determined in three commercial dosage forms with high accuracy and without interference from commonly encountered excipients and additives. Good recoveries were obtained with both synthetic mixtures and commercial tablets. The results obtained were compared with those from pharmacopeial methods and found to be in good agreement. The results obtained from CLS and PCR were also compared with those obtained from a ¹D spectrophotometric method.     

Hall-effect and metal-nonmetal transition in copper-argon and lead-argon systems

Summary Hall-effect measurements have been made to find out the type of transition from metal to nonmetal in copper-argon and lead-argon films prepared at helium temperature. The Hall measurements indicate that the transition from metal to nonmetal is a new-type transition. Such a metal-nonmetal transition in metal-argon systems may be attributed to the combined effect of electron correlation intermediated by phase transition. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Importance of nanostructured vanadia for selective oxidation of propane to acrylic acid

Highly dispersed nanostructured vanadia supported on mesoporous silica SBA-15, prepared by controlled grafting/ion-exchange, has been found to exhibit high selectivities in propane partial oxidation to acrylic acid demonstrating its unique potential for mixed metal oxide catalyst development.     

3D graphical representation of protein sequences and their statistical characterization

Based on three physicochemical properties of amino acid side chains, we proposed a novel unique 3D graphical representation of protein sequences. Then, we constructed two vectors of three components as mathematical objects to characterize protein sequences numerically. The similarity/dissimilarity analysis among nine ND5 protein sequences proved the utility of our approach. A correlation and significance analysis have been provided to compare our results and the sequence homology.     

Changes in the haemocytes of Agrotis ipsilon larvae (Lepidoptera: Noctuidae) in relation to dimilin and Bacillus thuringiensis infections

Five types of haemocytes are observed in the fourth larval instar of the black cutworm, Agrotis ipsilon: prohaemocytes (PRs), plasmatocytes (PLs), granulocytes (GRs), spherule cells (SPs) and adipohaemocytes (ADs). Infection of A. ipsilon fourth larval instar with Bacillus thuringiensis and dimilin resulted in a reduction of the total haemocyte count. Changes in the differential haemocyte population during bacterial and dimilin infections have been assessed. The PRs % decreased significantly while SPs, PLs, and GRs % increased significantly after the application of the two insecticides at 12 and 24 h. Ultrastructural alternations and malformations have been observed in circulating haemocytes of A. ipsilon larvae treated with dimilin and B. thuringiensis.     

Nonlinear stability of an axial electric field: Effect of interfacial charge relaxation

We introduce a nonlinear perturbation technique to third order, to study the stability between two cylindrical inviscid fluids, subjected to an axial electric field. The study takes into account the relaxation of electrical charges at the interface between the two fluids. At first order, a linear dispersion relation is obtained. Analytical and numerical results for the overstability and incipient instability conditions are given. For perfect dielectric fluids, the electric field has a stabilizing influence, while for leaky dielectric fluids, the electric field can have either a stabilizing or a destabilizing influence depending on the conductivity and permittivity ratios of the two fluids. At higher order, a nonlinear dispersion relation (nonlinear Ginzburg–Landau equation) is derived, describing the evolution of wave packets of the problem. For leaky dielectric fluids near the marginal state, a nonlinear diffusion equation (nonlinear incipient instability) is obtained. For perfect dielectric fluids, two cubic nonlinear Schrödinger equations are obtained. One of these equations to determine a nonlinear cutoff electric field separating stable and unstable disturbance, whereas the other is used to analyze the stability of the system. It is found that the nonlinear stability criterion depending on the ratio of permittivity, Such effects can only be explained successfully in the nonlinear sense, as the linear analysis unsuccessful to inform about them.