On some extremal problems in H p and the prediction ofL p -harmonizable stochastic processes

Summary We providesimple andsuccinct solutions to two dual extremal problems in the Hardy spacesH ^p , and to an aspect of the linear prediction problem for a certain class of discrete and continuous parameter L ^p -harmonizable stochastic processes, for all 1p<. Two of the results presented appear new. The methods of proof of the rest of the results provide alternatesimpler andshorter proofs for some earlier known theorems.This research is partially supported by AFSOR Grant No. 90-016 8 and the University of Tennessee Science Alliance, a State of Tennessee Center of Excellence     

Polarographische Untersuchung der Substitutionsreduktion des Kupfer(II)-?thylendiamintetraacetat-Chelats in Gegenwart von Calciumion

Zusammenfassung Die Reduktion des Kupfer(II)-ÄDTA-Chelats an der Quecksilbertropfelektrode wird durch Calciumion begünstigt, da das durch die Reduktion freigesetzte ÄDTA-Anion mit Calciumion reagiert. Die theoretischen Voraussagen wurden experimentell bestätigt, wobei eine Grundlösung aus Kaliumchlorid und Ammoniak verwendet wurde.

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Polarographic study of the substitution reduction of copper(II) ethylenediaminetetraacetate chelate in the presence of calcium ion

Summary The reduction of copper(II)-EDTA chelate at the dropping mercury electrode is facilitated by calcium ion, because the EDTA anion liberated by the reduction will react with that ion. The theoretical prediction was confirmed experimentally in a supporting electrolyte consisting of potassium chloride and ammonia.

Einer von uns (A. R. R.) ist dem Unterrichtsministerium Japans sehr dankbar, das ihm ein Stipendium 1974/76 verliehen und seinen Aufenthalt in Japan ermöglicht hatte.     

Applications of Singh-Rajput Mes in Recall Operations of Quantum Associative Memory for a Two- Qubit System

Recall operations of quantum associative memory (QuAM) have been conducted separately through evolutionary as well as non-evolutionary processes in terms of unitary and non- unitary operators respectively by separately choosing our recently derived maximally entangled states (Singh-Rajput MES) and Bell’s MES as memory states for various queries and it has been shown that in each case the choices of Singh-Rajput MES as valid memory states are much more suitable than those of Bell’s MES. it has been demonstrated that in both the types of recall processes the first and the fourth states of Singh-Rajput MES are most suitable choices as memory states for the queries ‘11’ and ‘00’ respectively while none of the Bell’s MES is a suitable choice as valid memory state in these recall processes. It has been demonstrated that all the four states of Singh-Rajput MES are suitable choice as valid memory states for the queries ‘1?’, ‘?1’, ‘?0’ and ‘0?’ while none of the Bell’s MES is suitable choice as the valid memory state for these queries also.     

Low-dimensionality effects in the melting of a Langmuir-Blodgett multilayer

Low-dimensionality effects in the melting behavior of a cadmium arachidate Langmuir-Blodgett multilayer have been studied. Depth resolved information about structural changes occurring with temperature is obtained using in-plane X-ray diffraction under standing wave conditions. The surface region exhibits a distinctly different melting behavior as compared to the bulk of the film. While in the bulk of a 13-monolayer cadmium arachidate multilayer, the crystalline phase directly transforms to a tilted hexaticlike phase at 360 K, in the near surface region transformation occurs via an intermediate smectic phase. This behavior of the surface region is similar to that observed in two-dimensional crystals. Thus even in a thick Langmuir-Blodgett multilayer, the surface region exhibits low-dimensionality effects.     

Concise synthesis of a pentasaccharide related to the anti-leishmanial triterpenoid saponin isolated from Maesa balansae

Concise synthesis of the glycone part (a pentasaccharide) of the anti-leishmanial triterpenoid saponin isolated from Maesa balansae is reported. A late-stage TEMPO-mediated oxidation of a primary hydroxyl group to carboxylic acid has been achieved under phase-transfer conditions. Glycosylations were performed either by thioglycoside or glycosyl trichloroacetimidate activation using sulfuric acid immobilized on silica (H2SO4-silica) in conjunction with N-iodosuccinimide and alone, respectively. H2SO4-silica was proved to be a better choice as promoter than conventional Lewis acid promoters such as TfOH or TMSOTf.     

Co(II) anchored glutaraldehyde crosslinked magnetic chitosan nanoparticles (MCS) for synthesis of 2,4,5‐trisubstituted and 1,2,4,5‐tetrasubstituted imidazoles

A simple, highly efficient and green synthesis of 2,4,5‐trisubsituted and 1,2,4,5‐tetrasubstituted imidazoles was developed using a novel MCS‐GT@Co(II) magnetically recoverable and recyclable catalyst under refluxing conditions with ethanol as a solvent. The catalyst was prepared by immobilization of chitosan onto Fe₃O₄ using glutaraldehyde as crosslinker followed by Co(II) ion immobilization via cobalt acetate. The catalyst was characterized using various techniques. For organic products determination, ¹H NMR, ¹³C NMR and Fourier transform infrared spectroscopies were used. The reaction was also tried with individual components of the catalyst, but the synergistic effect of the components in the prepared catalyst showed the highest yield and shortest reaction time.     

Sucrose chelated auto combustion synthesis of BiFeO3 nanoparticles: Magnetically recoverable catalyst for the one‐pot synthesis of polyhydroquinoline

Sucrose chelated Bismuth ferrite (BiFeO₃) nanoparticles as a novel heterogeneous catalyst was synthesized by an auto combustion route. Different calcination temperatures (150 °C, 450 °C, 550 °C, 650 °C, 750 °C and 850 °C) have been employed to obtain single phased BiFeO₃ nanoparticles. The perovskite structure formation and disappearance of organic phase (sucrose) was obtained by Fourier transform infrared spectroscopy (FT‐IR). Phase determination and structural characterization was carried out by powder X‐ray diffraction (XRD). The magnetic properties were analyzed by vibrating sample magnetometer (VSM) whereas surface area/pore volume was obtained by Brunauer–Emmett–Teller (BET). Transmission electron microscope (TEM) analyzed the particles size and morphology. Thermal stability was investigated by thermogravimetric analysis (TGA) and determination of constituent elements was carried out by X‐ray Photo‐Electron Spectroscopy (XPS). Raman spectroscopy confirmed the perovskite structure of the synthesized materials. The BiFeO₃ nanoparticles so obtained were employed as heterogeneous catalyst for the synthesis of polyhydroquinoline derivatives. All the polyhydroquinoline derivatives were characterized by Fourier transform infrared spectroscopy (FT‐IR) and Nuclear magnetic resonance spectroscopy (¹H NMR). For the very first time ever we have used BiFeO₃ as a recyclable magnetic nanocatalyst in the one‐pot four component cyclization reaction of benzaldehyde, ethylacetoacetate/methylacetoacetate, dimedone/cyclohexane‐1,3‐dione, and ammonium acetate for the synthesis of polyhydroquinoline derivatives without solvent under refluxing conditions to provide excellent yields of products. BiFeO₃ nanocatalyst (without any functionalization/surface coatings) shows easy magnetic separation, recyclability, reusability along with excellent yield of polyhydroquinoline derivatives in an economic and benign way.     

RP–LC Simultaneous Determination of Aconitine,Solanine and Piperine in an Ayurvedic Medicine

By optimizing the extraction, separation and analytical conditions, a reliable, rapid, simple and accurate liquid chromatography method with UV detection was developed for the simultaneous quantitative determination of aconitine, solanine and piperine in an ayurvedic preparation prepared from Aconitum ferox, Solanum indicum, Piper nigrum and Piper longum. The separation of these alkaloids was achieved on an reversed phase C-18 column (250 mm × 4.6 mm ID, 5 μm particle size), with isocratic elution using a mixture of acetonitrile–potassium hydrogen phosphate buffer (10 mM, pH 7.5)–methanol (60:25:15, v/v) at a flow rate of 1 mL min⁻¹ with UV detection at 227 nm for aconitine and solanine while 343 nm for piperine. The calibration curves were linear with correlation coefficients of 0.9990, 0.9942, 0.9989 for solanine, piperine and aconitine, respectively. The % Relative standard deviation (%RSD) values were less than 2% in the concentration range of 10–100 μg mL⁻¹ for all the three alkaloids. Intra-day assay and inter-day assay precision of the analytes were less than 2%, and the average recovery rates obtained were in the range of 98–102% for all with %RSD below 2%. Quantitative analysis of the alkaloids in the laboratory and marketed formulations showed that the contents of the alkaloids varied significantly. This method can provide a scientific and technical platform to the product manufacturers for setting up a quality control standard as well as to the public for quality and safety assurance of the proprietary ayurvedic formulations.