Dynamics of Random One-Dimensional ±J Systems

Finite chains of a two-state random Potts spin model with periodic boundary conditions are studied within Glauber dynamics. The spin exchange is assumed random with frustration between ferro and antiferromagnetic values (±J). Time-dependent fluctuations are induced by periodic temperature oscillations. Master type differential equations for spin correlation functions are solved within linear response theory. The spectrum of relaxation times are calculated at different temperatures. The ±J Potts glass chains undergo a zero temperature phase transition. The barriers against inversion of the spin chain take only two values; 0 and 2|J|. The temperature behaviour of specific heat is characterized by rounded peaks. The frequency dependence displays two plateaus for the real part of specific heat and two corresponding peaks for the imaginary part. The dynamic specific heat is not affected by the longest relaxing mode like susceptibility. The time separation of the modes is demonstrated by the Cole-Cole plots.     

Parametric Study of Nonplanar Dust Acoustic Solitons in Two‐Dimensional Superthermal Dusty Plasmas

The nonlinear properties of two dimensional low‐frequency electrostatic excitations of charged dust particles (or defects) are studied in a collisionless, unmagnetized dusty plasma. A fully ionized three‐component model plasma consisting of kappa distributed electrons, Maxwellian ions, and negatively charged massive dust grains is considered. In this regard, the well known reductive perturbation technique is used to the hydrodynamical equations and the Poisson equation, obtaining the cylindrical Kadomtsev–Petviashvili (CKP) equation. A parametric investigation indicates that the structural characteristics of these nonlinear excitations (width, amplitude) are significantly affected by the plasma nonthermality as well as by the relevant plasma parameters, such as dust concentration and dust temperature. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Appraisal of radioactivity and associated radiation hazards in sand samples of four rivers of Punjab province, Pakistan

Natural and anthropogenic radioactivity of sand and water samples collected from the four big rivers of Punjab province, Pakistan, was measured using a high-purity germanium detector coupled with a high resolution multichannel analyser. The average concentration of the naturally occurring radionuclides (226)Ra, (232)Th and (40)K in all the sand samples from the rivers Jhelum, Chenab, Ravi and Indus was found to be 22±0.6, 36±1 and 287±10 Bq kg (-1), respectively, while the concentration of the anthropogenic radionuclide (137)Cs was found to be below the minimum detectable activity, i.e. ~1.2 Bq?kg (-1). All the sand samples have Ra(eq) concentrations lower than the limit of 370 Bq kg (-1). Indoor (H (in)) and outdoor (H (out)) radiation hazard indices were calculated for the samples to assess the radiation hazards arising due to the use of this sand in construction, and were found to be less than unity in the study area. Calculated values of the absorbed dose rate were less than the typical world average value of 59 nGy h (-1), and the annual effective dose rate was also less than the typical world value of 70 μSv, except in the Indus river, in which it is slightly higher then the world average. Results show that the measured values are comparable with other global radioactivity measurements. None of the studied riverbeds was considered a radiological hazard, and their sand can be safely used in construction.     

Additive preservers of Drazin invertible operators with bounded index

Let B(X) be the algebra of all bounded linear operators on an infinite-dimensional complex or real Banach space X. Given an integer n ≥ 1, we show that an additive surjective map Φ on B(X)preserves Drazin invertible operators of index non-greater than n in both directions if and only if Φ is either of the form Φ(T) = αATA~(-1) or of the form Φ(T) = αBT~*B~(-1) where α is a non-zero scalar,A:X → X and B:X~*→ X are two bounded invertible linear or conjugate linear operators.     

Characterization and properties of low-linear-density polyethylene/Typha latifolia composites

The characterization of the effects of different sizes and loadings of Typha latifolia on the tensile, thermal, and morphological properties of linear-low-density polyethylene (LLDPE)/T. latifolia composites were evaluated using tensile test, Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy analyses. Results indicated the tensile strength and elongation at break decreased as T. latifolia loading increased. However, T. latifolia fine size (fs) exhibited better tensile properties than coarse size at the same loading in the composite. T. latifolia (15%, fs) recorded higher thermal stability than LLDPE control and other T. latifolia loadings and sizes due to the strong interaction of T. latifolia (15%, fs) in LLDPE matrix as shown in morphology.     

Mechanistic Insights into the Ameliorative Effect of Cichoriin on Diabetic Rats—Assisted with an In Silico Approach

Type 2 diabetes mellitus is considered to be a substantial socioeconomic burden worldwide on both patients and governments. Coumarins are biomolecules with a diversity of biological activities. The current investigation aimed to explore the ameliorative effects of cichoriin, which is a type of coumarin, on high-fat diet/streptozotocin (HFD/STZ)-induced diabetic rats. Methods: Rats were allocated into five groups. Group I was considered as the control group, while the other groups were HFD/STZ-induced diabetic rats. Group II was assigned as the diabetic control. Groups III and IV were treated with cichoriin (50 or 100 mg/kg, respectively). Group V received glibenclamide (5 mg/kg) (as a positive control). The blood glucose (BG), serum insulin, triglycerides (TG), total cholesterol (TC), total antioxidant capacity (TAC), catalase, hepatic superoxide dismutase (SOD) and content of malondialdehyde (MDA) were assessed. Histopathological and immunohistochemistry analysis of pancreatic tissue were performed. mRNA and protein expressions of GLUT4, AMPK, and PI3K were estimated. Results: Cichoriin treatment ameliorated HFD/STZ-induced diabetic conditions and mitigated the histopathological characteristics of the pancreas, as well as increasing pancreatic insulin expression. This decreased the levels of BG, TG, TC, and MDA and improved the TAC, catalase and SOD contents. Cichoriin demonstrated upregulation of mRNA and protein expressions of GLUT4, AMPK, and PI3K. The in silico binding of cichoriin with GLUT4, AMPK, and PI3K supported the possible current activities. Conclusion: Collectively, this work highlighted the potential role of cichoriin in mitigating HFD/STZ-induced diabetic conditions and showed it to be a valuable product.     

Improving the selectivity of non-polar alkanes, alkenes, and aromatic hydrocarbon compounds by the application of acetonitrile as a Cl reagent

The selective enhancement of membrane introduction mass spectrometry for non-polar alkanes, alkenes, and aromatic hydrocarbon compounds by the application of acetonitrile as a chemical ionization reagent was investigated. Acetonitrile Cl is able to produce specific fragment ions for many of the compounds test and this can be used to identify and quantify the parent neutrals. This method provided relatively high detection limits of the test compounds. This method could potentially be useful for analytical applications such as the detection of non-polar hydrocarbons for environmental studies if CH₃CN Cl/MIMS is coupled with a preconcentration method.     

Preparation of highly selective solid-phase extractants for Cibacron reactive dyes using molecularly imprinted polymers

Selective polymeric extractants were prepared for preconcentration of Cibacron reactive red dye, a dye that is often applied with Cibacron reactive blue and Cibacron reactive yellow for dyeing of fabrics. The best extractant was fabricated (in chloroform) using methacrylic acid (as monomer), ethylene glycol dimethacrylate (as crosslinker), AIBN (as initiator for polymerization), and red dye as template molecule, with a molar stoichiometric ratio of 8.0:40.0:2.5:0.63, respectively. The structure of the molecularly imprinted polymer (MIP) was robust, and resisted dissolution up to 260 °C. Compared with the un-imprinted polymer, the imprinted product has a large specific surface area which improved its adsorption capacity. The effect of imprinting was obvious from the adsorption capacity measured at pH 4 for red dye (the imprinted molecule), which was increased from 24.0 to 79.3 mg g⁻¹ after imprinting. Equilibrium adsorption studies revealed that the dye-imprinted-polymer enables efficient extraction of red dye even in the presence of blue and yellow dyes which have similar chemical natures to the red dye. The selectivity coefficients S _{red dye/dye}, were 13.9 and 17.1 relative to the yellow and blue dyes, respectively. The MIP was found to be effective for red dye preconcentration, with a preconcentration factor of 100, from tap water and treated textile wastewater. The factors affecting extraction of red dye by the MIP were studied and optimized. Under the optimized extraction conditions, red dye was selectively quantified in the presence of other competing dyes at a concentration of 20 μg L⁻¹ from different water systems with satisfactory recoveries (91–95%) and RSD values (∼5.0%).     

Yttria‐based sol–gel coating for capillary microextraction online coupled to high‐performance liquid chromatography

This work about the development of yttria‐based polymeric coating using [bis(hydroxyethyl) amine] terminated polydimethylsiloxanes and yttrium trimethoxyethoxide inside the capillary. The coated capillary was utilized for online capillary microextraction and high‐performance liquid chromatography analysis. The prepared coating material was characterized using scanning electron microscopy, X‐ray photoelectron spectroscopy, energy dispersive X‐ray spectrometry, and thermogravimetric analysis. The coated capillary with polymer presented better extraction efficiency compared with the pure yttria‐based coated capillary with applicability in extreme pH environments (pH 0–pH 14). Excellent extraction towards polyaromatic hydrocarbons, aldehydes, ketones, alcohols, phenols, and amides was observed with limit of detection ranging from 0.18 to 7.35 ng/mL (S/N = 3) and reproducibility in between 0.6 and 6.8% (n = 3). Capillary‐to‐capillary extraction analysis has presented reproducibility between 4.1 and 9.9%. The analysis provided linear response for seven selected phenols in the range of 5–200 ng/mL with R² values between 0.9971 and 0.9998. The inter‐day, intra‐day, and capillary‐to‐capillary reproducibility for phenols was also <10%. Real sample analysis by spiking 5, 50, and 200 ng/mL of phenols in wastewater and pool‐water produced recovery between 84.7 and 94.3% and reproducibility within 7.6% (n = 3).     

A novel carbon/chitosan paste electrode for electrochemical detection of normetanephrine in the urine

Normetanephrine is a marker for pheochromocytoma, a rare catecholamine-secreting and neuroendocrine tumor, that arises from sympathetic and parasympathetic paraganglia. In this work, a novel carbon/chitosan electrode paste was used for sensitive voltammetric determination of normetanephrine and dopamine in the presence of ascorbic acid and uric acid. The modified electrode has shown an increase in the effective area of up to 68%, well-separated oxidation peaks, and an excellent electrocatalytic activity. The electrochemical response characteristics were investigated by cyclic and differential pulse voltammetry. Interestingly, high sensitivity and selectivity in the linear range of normetanephrine, dopamine, ascorbic acid, and uric acid concentrations were observed. The present method was applied in the urine sample and satisfactory results were obtained showing that this electrode is very suitable in pharmaceutical and clinical preparations.