Structural changes in Poly(lactic acid)–zeolite nanocomposites exposed to 60Co gamma rays

Poly(lactic acid) (PLA) nanocomposites containing 3%, 5% and 7% zeolite used in the present research study were prepared by solution casting. The PLA nanocomposites were structurally characterized by Scanning Electron Microscopy and Fourier-transform infrared spectroscopy. The effects of the gamma radiation at the absorbed doses of 10, 15 and 20?kGy on the structures and thermal properties of the nanocomposites were investigated in a tetrahydrofuran solvent. Thermodecomposition tests and analyses were carried within 30–500°C range at the rate of 10°C?min^?1 by thermogravimetric analysis (TG). The activation energies for thermal degradation of the nanocomposites were calculated from their TG data by Flynn–Wall–Ozawa method. The G values of the nanocomposites were calculated based on molecular weights which were measured by means of gel permeation chromatography before and after the gamma irradiation. The E_a and molecular weight results showed that addition of zeolite to the PLA affected the radiation resistance of the polymer.     

Cytotoxic effect,enzyme inhibition,and in silico studies of some novel N-substituted sulfonyl amides incorporating 1,3,4-oxadiazol structural motif

Molecular Diversity - The acetylcholinesterase and carbonic anhydrase inhibitors (AChEIs and hCAIs) remain key therapeutic agents for many bioactivities such as anti-Alzheimer and antiobesity...     

Inflation and inflation uncertainty: A dynamic framework

This paper aims to investigate the direct relationship between inflation and inflation uncertainty by employing a dynamic method for the monthly country–region–place United States data for the time period 1976–2007. While the bulk of previous studies has employed GARCH models in investigating the link between inflation and inflation uncertainty, in this study Stochastic Volatility in Mean models are used to capture the shocks to inflation uncertainty within a dynamic framework. These models allow researchers to assess the dynamic effects of innovations in inflation as well as inflation volatility on inflation and inflation volatility over time, by incorporating the unobserved volatility as an explanatory variable in the mean (inflation) equation. Empirical findings suggest that innovations in inflation volatility increases inflation. This evidence is robust across various definitions of inflation and different sub-periods.     

Thermoelectric properties of stannite-phase CuZn2AS4 (CZAS; A=Al,Ga and In) nanocrystals for solar energy conversion applications

The current study aimed to comprehensively investigate structural, electronic, optical and transport properties of quaternary semiconductor CuZn₂AS₄ (CZAS; A=Al, Ga and In) nanocrystals (NCs). Based on energy considerations, the stannite structure (I-42m; No. 121) is found to be more stable than the kesterite (I-4; No.82) and wurtzite (P6₃mc; No.186) type structures. By means of hybrid functional calculations, these nanocrystals have direct band gap of 0.81–1.71 eV with a high absorption coefficient of >10⁴ cm^?1, which are well-suited for use in solar energy-conversion applications. Some of the latest advances in applications of these nanocrystals in thermoelectric applications are also highlighted in the current study. It is observed that transport coefficients of these materials are found to be nearly direction independent and isotropic. All three samples are p-type conductors at room temperature. Especially, the Seebeck coefficient of CuZn₂AlS₄ is even larger than that of CuZn₂GaS₄ and CuZn₂InS₄ under the studied carrier concentration and temperature region. The maximum figure of merit (ZT) reaches 0.982 (0.977), 0.984 (0.974) and 0.53 (0.955) for p-type (n-type) CuZn₂AlS₄, CuZn₂GaS₄, and CuZn₂InS₄, respectively, at 300 K. The high Seebeck coefficients, high figure of merit and low thermal conductivities make these systems good candidates for high-efficiency thermoelectric conversion applications.     

Removal of Phenolic and Lignin Compounds from Bleached Kraft Mill Effluent by Fly Ash and Sepiolite

This study aimed to remove phenolic and lignin compounds from paper mill industry (4500 m³/h) wastewaters, which is discharged to sea from a plant located in the western Turkey. As adsorbent, fly ash, raw sepiolite and heat-activated sepiolite were used. The effect of factors such as, particle size, temperature and pH on adsorption process was investigated. From kinetic studies, equilibrium time was found as 1 h for both. The kinetic data supports pseudo-second order model but shows very poor fit for pseudo-first order model. Intraparticle model also shows that there are two separate stages in sorption process, namely, external diffusion and pore diffusion. Adsorption isotherms for fly ash and activated sepiolite were obtained at two different temperatures. From experiments carried out at different pHs, it was observed that pH plays an important role in the adsorption process in removing of both lignin and phenolic compounds, providing both ionizating the compounds and modifying sorbent surfaces. It was also observed that heat-activated sepiolite is more effective than raw sepiolite and fly ash to remove these compounds. Adsorption of lignin and phenolic compounds increases with decreasing particle size. In addition, the efficiency of adsorption decreases with increasing adsorption temperature for both fly ash and untreated sepiolite.     

A metric to quantify college football’s topsy-turvy season

Based on ranking change of college football teams from week to week in AP polls, a metric to measure the topsy-turviness of college football weeks has been developed. Six recent seasons (2002–2007) were used in the analysis. The 2007 season turned out to be the most topsy-turvy, while the 2004 season was the most stable. These findings were confirmed with other measurements, such as change in ranking from week to week and number of weeks deemed topsy-turvy or stable based on the average and standard deviation of all TT factor numbers. Other polls, such as the USA Today poll, resulted in similar trends. In-depth statistical analysis of the weekly TT factors did not indicate the presence of nonrandomness throughout the weekly topsy-turvy season. When using a randomized complete block design, statistically significant differences were detected in the mean TT factors across weeks and seasons. However, no significant trends were found in the TT factors, except for in the last week before the bowls are played.     

C-C and C-H bond activation in the fragmentation of the [M + Ni]+ adducts of aliphatic amino acids

The major metal-containing species formed upon fast atom bombardment of amino acid/Ni⁺² mixtures is the [M + Ni]⁺ adduct, involving reduction of the Ni⁺² to the +1 oxidation state. By contrast, electrospray ionization of amino acid/Ni⁺² mixtures produces predominantly [Ni(M ? H)M]⁺; this species, on collisional activation, produces predominantly [M + Ni]⁺ by elimination of [M - H], presumably a carboxylate radical. The unimolecular fragmentation reactions occurring on the metastable ion time scale for the [M + Ni]⁺ adducts of a variety of α-amino acids have been recorded. The adducts with phenylalanine, α-aminoisobutyric acid and α-aminobutyric acid fragment by elimination of H₂O, H₂O + CO and, to a minor extent, by elimination of CO₂. These reactions are similar to those observed for the [M + Cu]⁺ adducts of α-amino acids. A reaction distinctive for the [M + Ni]⁺ adducts involves formation of the immonium ion RCH=NH ₂ ⁺ . By contrast, the [M + Ni]⁺ adducts with leucine, isoleucine, and norleucine show extensive metastable ion fragmentation by elimination of H₂, CH₄, C₂H₄, C₃H₆, and C₄H₈, with the relative importance of the different fragmentation channels depending on the configuration of the C₄H₉ side chain. These results are interpreted in terms of C-C and C-H bond activation of the C₄H₉ side chain by the Ni⁺. The adducts with valine and norvaline fragment in a fashion similar to the adduct with phenylalanine, except that minor elimination of C₃H₆ is observed.     

Simultaneous Determination and Drug Dissolution Testing of Combined Amlodipine Tablet Formulations Using RP-LC

In the proposed work, the simultaneous analysis of amlodipine–rosuvastatin and amlodipine–atorvastatin in their dosage forms was achieved. Simultaneous dissolution profiles of the amlodipine–rosuvastatin and amlodipine–atorvastatin tablets are realized using Apparatus II with a simple, accurate and precise RP-LC method. The mobile phase consisting of 0.2 % H₃PO₄ and pH 5:methanol:acetonitrile (46:27:27) was used. The samples of 10 µL were injected onto a Zorbax SB C18 (100 mm, 4.6 mm, 3.5 µm particle size) column with 1.2 µL min⁻¹ flow rate. The samples were detected at 236 nm. By plotting peak area ratios vs. concentration, the linearity for amlodipine–rosuvastatin and amlodipine–atorvastatin was determined. With the developed RP-LC method, AML, ROS and ATOR were detected within the range of 0.25–10, 0.5–10 and 0.25–25 µg mL⁻¹, respectively. LOD and LOQ values were also calculated as 0.028, 0.058, 0.021 and 0.095 µg mL⁻¹, 0.195 µg mL⁻¹, 0.070 µg mL⁻¹ for AML, ROS and ATOR, respectively. System suitability tests parameters, such as capacity factor, selectivity to previous peak, selectivity to next peak, resolution to previous peak, resolution to next peak, tailing factor, theoretical number of plates, were performed and found coherent with the ICH guideline parameters. The proposed method has been extensively validated in terms of recovery, and recovery results were between 99 and 101 %. For proving the precision, between-day and within-day repeatability results of the method were proposed. The method can be used for the simultaneous determination of amlodipine–rosuvastatin and amlodipine–atorvastatin.

     

When some complement of a z-closed submodule is a summand

In this article we study modules with the condition that every z-closed submodule has a complement which is a direct summand. This new class of modules properly contains the class of extending modules. It is well known that the class of extending modules is closed under direct summands, but not under direct sums. In contrast to extending (or CS) modules, it is shown that the class of modules with former property is closed under direct sums. However we provide number of algebraic topological examples which show that this new class of modules is not closed under direct summands. To this end we obtain several results on the inheritance of the latter closure property.     

Thermal and magnetothermal properties of La0.5Pr0.5Mn2Si2

The thermal and magnetothermal properties of La_0.5Pr_0.5Mn₂Si₂ and isostructural LaFe₂Si₂ intermetallic compounds in the temperature range 4.5-303 K are reported with and without applied magnetic field. The electronic, lattice, and magnetic contributions to the heat capacity of La_0.5Pr_0.5Mn₂Si₂ are determined and analyzed. We have determined and from heat capacity experiments; the values are in line with those from the magnetization measurements. We conclude that in order to observe the anomaly in the heat capacity data around in the system, the transition around should occur in a narrow temperature interval.