Synthesis and Spectroscopic Investigations of Four New Y(Ⅲ), Ge(Ⅳ), W(Ⅵ) and Si(Ⅳ) Penicillin Antibiotic Drug Complexes

A four new penicillinate complexes were prepared through the chemical interactions of penicillin potassium salt (Pin) with YCl₃, GeCl₄, WCl₆ and SiCl₄ metal ions. These metal complexes were characterized using spectroscopic techniques (e.g. 1H-NMR, infrared, electronic UV-Vis) as well as elemental, conductivity, and magnetic measurements. The molar conductance values were highly, showing their electrolytic nature. The magnetic and electronic study strongly recommends the octahedral geometry of all penicillinate complexes. A monomeric structures of Pin complexes are proposed with octahedral coordinated metals ions. The metal ions are coordinated toward Pin as tridentate ligand through the amide and β-lactam carbonyls and a carboxylate group from penicillin. The in vitro antimicrobial activity of all the complexes, at concentrations in μg·mL-1, was screened against four bacterial pathogens, namely, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, and two kinds of fungi Aspergillus flavus and Candida albicans showed better activity compared to parent drug and control drug. The anti-cancer inhibition of the tungsten(Ⅵ) complex was assessed against the human hepato cellular carcinoma (HepG-2) tumor cell line with IC50 value is 646 μg·mL-1.     

Analytical expressions to calculate relative amounts of phases in a three-component phase diagram

The relative amounts of different phases in multiphase regions in the common three-component phase diagrams are usually estimated graphically using geometrical features of the diagram. The present contribution introduces algebraic expressions for the lines in the diagram, which allow these numbers to be calculated directly from the experimental results. The method is an extension of the classical methods, which were translated into convenient computer programs [Laughlin, R. G. The Aqueous Phase Behavior of Surfactants; Academic Press: New York, 1994] to calculate the amount of different phases for individual compositions. The introduction of analytical geometry allows simplified expressions to be used for the calculations and the amounts to be presented as continuous functions of the total composition.     

A contribution to simulating a three-dimensional larynx model using the finite element method

A three-dimensional model is presented to simulate the larynx during vocalization. The finite element method is used to calculate the airflow velocity and pressure along the larynx as well as tissue displacement. It is assumed that the larynx tissue is transversely isotropic and divided into three tissues: cover, ligament, and body. A contact-impact algorithm is incorporated to deal with the physics of the collision between both true vocal folds. The results show that the simulated larynx can reproduce the vertical and horizontal phase difference in the tissue movements and that the false vocal folds affect the pressure distribution over the larynx surfaces. The effects of exciting the larynx with different pressure drops are also investigated.     

Automatic estimation of the first subglottal resonance

This letter focuses on the automatic estimation of the first subglottal resonance (Sg1). A database comprising speech and subglottal data of native American English speakers and bilingual Spanish/English speakers was used for the analysis. Data from 11 speakers (five males and six females) were used to derive an empirical relation among the first formant frequency, fundamental frequency, and Sg1. Using the derived relation, Sg1 was automatically estimated from voiced sounds in English and Spanish sentences spoken by 22 different speakers (11 males and 11 females). The error in estimating Sg1 was less than 50 Hz, on average.     

A study of acoustic-to-articulatory inversion of speech by analysis-by-synthesis using chain matrices and the Maeda articulatory model

In this paper, a quantitative study of acoustic-to-articulatory inversion for vowel speech sounds by analysis-by-synthesis using the Maeda articulatory model is performed. For chain matrix calculation of vocal tract (VT) acoustics, the chain matrix derivatives with respect to area function are calculated and used in a quasi-Newton method for optimizing articulatory trajectories. The cost function includes a distance measure between natural and synthesized first three formants, and parameter regularization and continuity terms. Calibration of the Maeda model to two speakers, one male and one female, from the University of Wisconsin x-ray microbeam (XRMB) database, using a cost function, is discussed. Model adaptation includes scaling the overall VT and the pharyngeal region and modifying the outer VT outline using measured palate and pharyngeal traces. The inversion optimization is initialized by a fast search of an articulatory codebook, which was pruned using XRMB data to improve inversion results. Good agreement between estimated midsagittal VT outlines and measured XRMB tongue pellet positions was achieved for several vowels and diphthongs for the male speaker, with average pellet-VT outline distances around 0.15 cm, smooth articulatory trajectories, and less than 1% average error in the first three formants.     

Phase Behavior of Microemulsions Formulated with Sodium Alkyl Polypropylene Oxide Sulfate and a Cationic Hydrotrope

The partial ternary phase diagram of anionic extended surfactant of alkyl polypropylene oxide sulfate C₁₂(PO)₄SO₄ alone and combined with the cationic hydrotrope, tetrabutyl ammonium bromide with water and decane were determined under ambient conditions. Middle phase microemulsion was formulated using salinity scans in the dilute region of surfactant/brine/decane. Visual inspection as well as cross polarizer and optical microscopy were used to detect anisotropy. Spinning drop tensiometer was used to measure interfacial tension (IFT). The first ternary phase diagram using the extended surfactant alone showed three one phase regions, the anisotropic lamellar liquid crystalline phase, L _α and the isotropic L₁ micellar liquid and L₃ sponge phase. In the second ternary phase diagram using the extended surfactant combined with tetra butyl ammonium bromide, an isotropic micellar region, L ₁, appeared in the diluted area of the phase diagram. Meanwhile the L _α phase disappeared completely and the three phase region has a bluish transparent middle phase. Interfacial tension measurements between middle phase and brine, and between decane and brine yielded ultra low values. Calculated IFT values using the characteristic length obtained using De Gennes approximation gave almost half the measured values. The interfacial rigidity was also calculated and compared to values obtained from the literature.     

Effect of molecular structure on the phase behaviour of some liquid crystalline compounds and their mixtures VII. Ternary mixtures of enantiotropes

Transition temperatures of the ternary mixtures, prepared from compounds of the two series, 4-hexadecyloxyphenyl 4-substituted benzoates (Ia,b) and 4-substituted phenyl 4-hexadecyloxy benzoates (IIa,b) have been determined by differential scanning calorimetry and identified with polarized light microscopy. The cyano and nitro derivatives, in both series, were used because their molecules form enantiotropic phases. A new method was elaborated for the elucidation of the eutectic composition of any ternary system from the knowledge of the eutectic composition of the three individual binary mixtures.     

DC Electrical Conductivity of Polymercaptobenzothiazole Disulfide Copper Complex

Polymercaptobenzothiazole disulfide-copper complex PMBTS-Cu has been synthesized by reacting 2-mercaptobenzothiazole disulfide with CuCl₂ in absolute ethanol and dimethyl sulfoxide (DMSO) under reflux for 24 h. PMBTS-Cu has been characterized by several techniques using electronic spectra, elemental analyses, FTIR spectroscopy, and its solubility has been investigated. DC electrical conductivity variation with temperature, in the range 300–500 K, after annealing for 24 h at 100°C, and doping with different ratios of I₂, is determined for comparison. Doping was done in two ways: by mixing and chemically. Activation energies were calculated and the results were interpreted using the band energy model. DC electrical conductivity of I₂doped PMBTS-Cu complex increased with increasing temperature due to the variation of the carrier concentration with temperature as in the case of semiconductors. PMBTS-Cu complex has a copper ion in its backbone and copper salt is known to be a good dopant. Thus, these materials are doped internally, so the doped polymer-Cu complex are only one or two orders of magnitude higher in DC electrical conductivity than the annealed state. However, the energy gap is very small, which suggests suitability in applications like photovoltaic cells.