Temperature scanning ultrasonic velocity study of complex thermal transformations in solid lipid nanoparticles

The purpose of this study was to determine whether temperature scanning ultrasonic velocity measurements could be used to monitor the complex thermal transitions that occur during the crystallization and melting of triglyceride solid lipid nanoparticles (SLNs). Ultrasonic velocity ( u) measurements were compared with differential scanning calorimetry (DSC) measurements on tripalmitin emulsions that were cooled (from 75 to 5 degrees C) and then heated (from 5 to 75 degrees C) at 0.3 degrees C min (-1). There was an excellent correspondence between the thermal transitions observed in deltaDelta u/delta T versus temperature curves determined by ultrasound and heat flow versus temperature curves determined by DSC. In particular, both techniques were sensitive to the complex melting behavior of the solidified tripalmitin, which was attributed to the dependence of the melting point of the SLNs on particle size. These studies suggest that temperature scanning ultrasonic velocity measurements may prove to be a useful alternative to conventional DSC techniques for monitoring phase transitions in colloidal systems.     

Synthesis and photophysical properties of poly-(phenylenevinylene) dendrimers with a ruthenium tris-bipyridine core

The photophysical processes have been investigated in first, second and third generation dendrimers with poly-(phenylenevinylene) branches and a ruthenium tris-bipyridine core, RuDn (n = 1–3). These dendrimers show very efficient forward singlet–singlet energy transfer from the branches to the ruthenium core upon UV irradiation, with efficiencies of 0.99 for RuD1 and 0.88 for RuD2 and RuD3 in CH₂Cl₂. The RuDn dendrimers show a bi-exponential emission decay in CH₂Cl₂, when excited with a 460 nm light with short lifetimes, however, the emission decay lifetimes become mono-exponential in 10% Triton X-100 aqueous solution (τ = 840 ns for RuD1, 890 ns for RuD2 and 1120 ns for RuD3).     

An eco-friendly multi-analyte high-performance thin layer chromatographic densitometric determination of amoxicillin,metronidazole, and famotidine in their ternary mixtures and simulated gastric juice: A promising protocol for eradicating Helicobacter pylori

Gastrointestinal tract disorders constitute a heavy burden to healthcare providers. To eradicate Helicobacter pylori infection, different triple therapy protocols have been proposed. Among which are combinations of proton pump inhibitors (e.g., omeprazole), histamine-2 receptor antagonists (e.g., famotidine), along with antibiotics (e.g., amoxicillin). In this work, a sensitive and accurate high-performance thin-layer chromatographic method was developed for the simultaneous determination of amoxicillin, metronidazole, and famotidine in bulk powder and laboratory-prepared combined-tablet mixtures. Complete separation of the cited compounds was achieved using pre-coated silica gel plates with a mixture of methanol:chloroform:toluene:water:glacial acetic acid (5:2:1.5:0.5:0.1 v/v/v/v/v) as the mobile phase. The method was fully validated as per the international conference of harmonization guidelines. Good linearity, a correlation coefficient of 0.9991, was obtained in the concentration ranges 0.1–1.6 μg/band (amoxicillin), 0.1–0.9 μg/band (metronidazole), and 0.1–0.9 μg/band (famotidine). Since the method allowed the determination of the three compounds in combined tablets with a high degree of selectivity, accuracy, precision, with cost-effectiveness, it could be used for regular quality control. Moreover, the applicability of the proposed method was extended to the determination of the ternary mixture in simulated gastric juice. Method greenness was assessed using different green metrics.     

Determination of Esomeprazole on an Electropolymerized L‐arginine and β‐cyclodextrin Modified Screen Printed Carbon Electrode

The formation of an inclusion complex of the proton‐pump inhibitor (PPI) drug esomeprazole (ESO) with ß‐cyclodextrin (ß‐CD) has been investigated and proven by cyclic voltammetry (CV). The formation constant of the complex was determined. Thereafter, an electropolymerized β‐CD and L‐arginine (L‐arg) modified screen printed carbon electrode (P‐β‐CD‐L‐arg/SPCE) was developed for the determination of ESO using differential pulse adsorptive stripping voltammetry (DPAdSV). A significant enhancement of the peak current was observed when applying an accumulation step due to the effect of adsorption. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) further indicated that the polymer of β‐CD and L‐arg efficiently improved the electron transfer kinetic between analyte and electrode surface. Under the optimized conditions, the oxidation peak current was linearly proportional to the concentration of the drug in the range of 1.0×10^?8 to 1.0×10^?5 M. The DPAdSV method was successfully used to determine the concentrations of the drug in spiked human serum samples.     

Amalgamation,interpolation and epimorphisms in algebraic logic

In his landmark paper on amalgamation published in Algebra Universalis in 1971, Don Pigozzi posed some open questions in connection with amalgamation of subclasses of cylindric algebras. Some of these questions were originally raised by Comer, Daigneault, Johnson, McKenzie and others. In this paper we give answers to all these as well as a number of other related questions. Most of the solutions were found by the authors of this paper. However, a few were contributed by others who will of course be given due credit at the appropriate points. This paper is dedicated to Don Pigozzi on his retirement. Presented by R. W. Quackenbush. The first author’s research was supported by the Hungarian National Foundation for Scientific Research grants no T30314 and T23234. The second author’s research was supported by the Hungarian National Foundation for Scientific Reserach OKTA grant no T30314. All the new results in this article were announced by Judit Madarász in the Workshop on Abstract Algebraic Logic, held in Centre de Recerca Matematica Bellaterra, Spain July 1–5, 1997. Received December 15, 2002; accepted in final form January 3, 2006.     

Star‐Shaped Polyaromatic Ethers Coordinated to Redox‐Active Cyclopentadienyliron Moieties

This communication is focused on the controlled design of star‐shaped aromatic ethers with pendent cyclopentadienyliron moieties. A trimetallic core was prepared, which was then reacted with a number of oligomeric ether complexes to give star‐shaped polymers with six, nine, twelve and fifteen pendent cationic cyclopentadienyliron moieties. Cyclic voltammetric studies showed reduction of the iron centers between –0.99 and –1.41 V. Thermogravimetric analysis showed that loss of the metallic moieties occurred between 225 and 284°C.     

Novel method for preparation of poly(benzoxazinone‐imide)

A novel method was developed to prepare poly(benzoxazinone‐imide) by the dealcoholization of poly(amide‐imide), having pendent ethoxycarbonyl groups, which was prepared from poly(amide acid). The poly(amide acid) was prepared from the reaction of pyromellitic dianhydride and 4,4′‐diamino‐6‐ethoxycarbonyl benzanilide. The curing behavior of the poly(amide acid) was monitored by DSC, which indicated the presence of two broad endotherms, one with maximum at 153 °C due to imide‐ring formation and the other with maximum at 359 °C due to benzoxazinone‐ring formation. The poly(amide acid) was thermally treated at 300 °C/1 h to get poly(amide‐imide) with pendent ester groups, then at 350 °C/2 h to convert into poly(benzoxazinone‐imide) by dealcoholization. Viscoelastic measurements of the poly(amide‐imide) showed that the storage modulus dropped at about 280 °C with glass‐transition temperature (T_g ) at about 340 °C. The storage modulus of poly(benzoxazinone‐imide), however, was almost constant up to 400 °C and no T_g was detected below 400 °C. Also, the tensile modulus and tensile strength of the poly(benzoxazinone‐imide) was much higher than that of the poly(amide‐imide). The 5% decomposition of poly(benzoxazinone‐imide) film was at 535 °C, which reflects its excellent thermal stability. Also, poly(benzoxazinone‐imide) showed more hydrolytic stability against alkali in comparison to polyimides. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1647–1655, 2000     

ASACUSA MUSASHI: New progress with intense ultra slow antiproton beam

Our group “ASACUSA MUSASHI” has established an efficient way for accumulating antiprotons and extracting them as intense ultra-slow mono-energetic beams at the CERN-AD facility. This novel beam opens new frontiers for investigating a variety of physics. For realizing H? spectroscopy and the test for charge-parity-time symmetry, we have also developed the cusp trap, a combination of an anti-Helmholz superconducting coil and a multi-ring electrode trap, for trapping both antiprotons and positrons and then synthesizing antihydrogens. Recently, the cusp trap was practically used to accumulate antiprotons. The last piece for synthesizing antihydrogens in the cusp trap is the positron accumulator. We have developed a compact system to effectively accumulate positrons based on N₂ gas-buffer scheme with a specially designed high precision cylindrical multi-ring electrode trap. The recent progress of the developing work is an important milestone for upcoming antihydrogen science of ASACUSA MUSASHI.     

Conformational stability, r 0 structural parameters, barriers to internal rotation, ab initio calculations, and vibrational assignment for 2,2-difluoroethanol

The infrared spectra (4,000–30 cm^?1) of the gas and solid and the Raman spectrum of liquid 2,2-difluoroethanol as well as variable temperature infrared spectra of krypton/xenon solutions have been recorded. From all these data, two (Gg and Tg) out of the five possible stable conformers have been confidently identified. The order of the stabilities has been predicted to be Gg > Tg > Gt > Gg′ > Tt by utilizing ab initio MP2 (full) and DFT (B3LYP method) calculations, where the first indicator (capital letter) is in reference to rotation around the C–C bond (G = gauche or T = trans) and the second one (small letter) refers to the orientation of the hydroxyl group. The percentage of the minor conformer Tg, at ambient temperature, is estimated to be (16 ± 3%). The optimized geometries, fundamental frequencies, infrared intensities, Raman activities, and depolarization values as well as centrifugal distortion constants have been obtained from ab initio and density functional theory calculations by utilizing a variety of basis sets as well as those with diffuse functions. By utilizing the previously reported microwave rotational constants for two isotopomers of the Gg conformer combined with ab initio MP2(full)/6-311+G(d,p) predicted structural values, adjusted r ₀ parameters have been obtained. The determined heavy atom distances (Å) for the Gg conformer are: C₁–C₂ = 1.510(3), C₂–F₄ = 1.371(3), C₂–F₅ = 1.362(3), C₁–O₃ = 1.412(3) Å and angles ∠O₃C₁C₂ = 111.0(5), ∠F₄C₂C₁ = 108.8(5), ∠F₅C₂C₁ = 109.8(5), τF₄C₂C₁O₃ = 63.5(5), τF₅C₂C₁O₃ = 179.1(5)°. Barriers of internal rotation have been obtained and vibrational assignments for the Gg and Tg conformers are given. The five predicted centrifugal distortion constants compared to the experimental values are in reasonable agreement except for ?_K, which appears to be in error. The results are discussed and the structural parameters compared to the corresponding ones for 2-fluoroethanol and 2,2,2-trifluoroethanol where those for the latter molecule have been redetermined. The currently determined heavy atom parameters are quite different from the earlier assumed values, which led to poor values of the six adjusted parameters.     

METHOD OF CENTERS ALGORITHM FOR MULTI-OBJECTIVE PROGRAMMING PROBLEMS

In this paper, we consider a method of centers for solving multi-objective programming problems, where the objective functions involved are concave functions and the set of feasible points is convex. The algorithm is defined so that the sub-problems that must be solved during its execution may be solved by finite-step procedures. Conditions are given under which the algorithm generates sequences of feasible points and constraint multiplier vectors that have accumulation points satisfying the KKT conditions. Finally, we establish convergence of the proposed method of centers algorithm for solving multiobjective programming problems.