Colored scalar in a chromomagnetic field

The motion of colored scalar particles in a constant color magnetic field is considered. The Klein-Gordon equation is solved in this background and the energy spectrum is quantized by boundary conditions. The unitary transformation diagonalizing this equation and the states with definite energy are found.     

Infinitely many solutions for perturbed impulsive fractional differential systems

In this paper, the existence of infinitely many solutions for perturbed systems of impulsive non-linear fractional differential equations including Lipschitz continuous non-linear terms is discussed. The approach is based on variational methods. In addition, examples are presented to illustrate the feasibility and effectiveness of the main results.     

Microwave-Induced Solvent-Free Synthesis and Antifungal Screening of Novel Spiro Heterocyclic Systems Containing 3,5-Diphenyl-7H-thiazolo[3,2-a]pyrimidine and Indolin-2-one

A microwave-induced technique has been developed for the synthesis of a series of novel spiro indoline-based heterocycles (7a–g) at atmospheric pressure in an open vessel using an environmentally benign procedure. This rapid method produces pure products in good yields within a few minutes in comparison to the conventional procedure developed for the synthesis of these heterocycles. The synthesized compounds have been screened in vitro for antifungal activity against two fungal strains (i.e., Aspergillus niger and Aspergillus flavus). All compounds have shown significant activity against these pathogens.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

The Essential Oil-Bearing Plants in the United Arab Emirates (UAE): An Overview

Essential Oils (EOs) are expensive hydrocarbons produced exclusively by specific species in the plant kingdom. Their applications have deep roots in traditional herbal medicine, which lacks scientific evidence. Nowadays, more than ever, there is a growing global interest in research-based discoveries that maintain and promote health conditions. Consequently, EOs became a much attractive topic for both research and industry, with revenues reaching billions of dollars annually. In this work, we provide key guidance to all essential oil-bearing plants growing in the United Arab Emirates (UAE). The comprehensive data were collected following an extensive, up-to-date literature review. The results identified 137 plant species, including indigenous and naturalized ones, in the UAE, citing over 180 published research articles. The general overview included plant botanical names, synonyms, common names (Arabic and English), families and taxonomic authority. The study acts as a baseline and accelerator for research, industry and discoveries in multiple disciplines relying on essential oil-bearing plants.     

Dielectric Study of Homogeneity in Some Binary Liquids in Their Supercooled State

In this work, we report a dielectric study of some binary mixtures in their supercooled region over a frequency range of 10⁶ to 10^–3 Hz. Differential scanning calorimetry measurements have been made above 100K. The samples studied here are DL-lactic acid (88% in aqueous solution), binary mixtures of dimethyl sulfoxide and acetic acid, of propylene glycol and cyclohexanol, and of 4-methyl-3-heptanol and tritolyl phosphate. The frequency dispersion of the relaxation spectra and the temperature dependence of the relaxation process have been critically examined for heterogeneity. The mixtures of dimethyl sulfoxide and acetic acid reveal a 1:1 complex formation. Some evidence of heterogeneity was found only in mixtures of 4-methyl-3-heptanol and tritolyl phosphate. For comparison, we have also studied liquid mixtures of isopropylbenzene with small quantities of acetone or fluorobenzene. These mixtures showed no signs of heterogeneity, although the relaxation spectra are broader than the spectrum of pure isopropylbenzene.     

Sub-Tg relaxations due to dipolar solutes in nonpolar glass-forming solvents

It is well known that rigid dipolar solutes (in smaller quantity) dispersed in a nonpolar glassy matrix exhibit a sub-T(g) (or beta(s)) relaxation due to the solute often designated as Johari-Goldstein (JG) relaxation, which is intermolecular in nature. In this article, we report the results of our study of such a sub-T(g) process in a wide variety of dipolar solutes in different glassy systems using dielectric spectroscopy over a frequency range of 20-10(6) Hz down to a temperature of 77 K. The T(g) of these solutions are determined using differential scanning calorimetry. The solvents used in this study are o-terphenyl (OTP), isopropylbenzene (IPB), and methylcyclohexane. In the case of rigid molecular solutes, like mono-halogen benzenes, the activation energy (DeltaE(beta)) of the beta(s) process is found to increase with decreasing T(g) of the solvent, with a corresponding decrease in the magnitude of the beta(s) process. In the case of more symmetrical molecular solute, for example, tert-butylchloride, the change in DeltaE(beta) is not very appreciable. These results emphasize the importance of the size of the cage of the host matrix in the relaxation of the solute molecules. We have also studied the sub-T(g) relaxation(s) due to some flexible molecular solutes, viz., 1butylbromide, 1hexylbromide, 1butylacetate, and benzylacetate. These solutes in IPB matrix exhibit only one relaxation, whereas in OTP matrix they exhibit an additional sub-T(g) process, which may be identified with a JG type of relaxation. These observations lead us to the conclusion that the beta process observed in the glassy states of these pure solutes is predominantly intramolecular in nature.     

COMPARATIVE STUDIES ON THE LETHAL, MUTAGENIC, AND RECOMBINOGENIC EFFECTS OF ULTRAVIOLET-A,-B,-C, AND VISIBLE LIGHT WITH AND WITHOUT 8-METHOXYPSORALEN IN Saccharomyces cerevisiae

Abstract
Genetic effects of UV-A, UV-B, UV-C, and the combination of 8-methoxypsoralen (8MOP) with UV-A or visible light were studied in the haploid strain XV185–14C and diploid strain D5 of Saccharomyces cerevisiae. The induction of his+, lys+, and horn+ reverse mutations was measured in strain XV185–14C. In strain D5 we measured the induction of genetically altered colonies, particularly twin spot colonies arising from a mitotic crossing-over. UV-C and UV-B induced point mutations at the three loci in the haploid strain and mitotic crossing-over and other genetic alterations in the diploid strain. UV-C was more mutagenic and recombinogenic than UV-B. UV-A or visible light alone did not induce genotoxic effects at the doses tested. However, UV-A plus 8-MOP produced lethal and mutagenic effects in the haploid strain XV185–14C, although mutagenic activity was less than that of UV-B. Visible light plus 8-MOP also induced genotoxic effects in strain XV185–14C. In the diploid strain D5, UV-A plus 8-MOP induced a higher frequency of genetic alterations than UV-B at comparative doses. Visible light plus 8-MOP was also genetically active in strain D5. The haploid strain was more sensitive to the lethal effects of UV-C, UV-B, UV-A, and impure visible light plus 8-MOP than the diploid strain.     

Controlling the yield behavior of fat-oil mixtures using cooling rate

The rheological behavior such as yielding of fat crystal networks are dictated by many variables. Among these variables, the shape of the constituent fat cluster is important yet relatively unexplored. In this work, we describe the rheological investigations of a fat-oil system which can be formulated to either contain bundles of needles or spherical clusters by controlling the cooling rate and fat concentration. Fat-oil mixtures containing high-fat concentrations exhibited weak frequency dependence of storage modulus (G ^′) and loss modulus (G ^″). The yielding behavior of the mixtures were investigated by large amplitude oscillatory shear (LAOS) rheology using strain and stress controlled modes. Lissajous-Bowditch plots and orthogonal set of Chebyshev polynomials were used to analyze the non-linearities associated with the yielded fat-oil mixtures. For a given fat concentration, the yield stress of fat networks obtained at low cooling rates (bundles of needles) were similar to that of networks obtained at high cooling rates (spherical clusters). However, after yielding, Lissajous-Bowditch plots suggested that the mixtures comprising of bundles of needles exhibited viscous-like behavior while the spherical clusters exhibited a plastic-like behavior. This was further supported by microscopy images of yielded fat-oil mixtures. Overall, for a given fat concentration, the two different shapes of fat clusters can give rise to networks of similar yield stress values but different behaviors after yielding.