Trapped Coupled Dielectric Overlay Guide Configuration at Millimeter Wave Frequencies

Trapped coupled dielectric overlay guide has several interesting characteristics useful for millimeter wave applications. Dispersion characteristics and wave impedance for even and odd modes are computed by using Effective Dielectric Constant (EDC) method. Dispersion curves realized for Trapped coupled overlay guide for various dielectric materials and dimensional parameters as a function of frequency. Conductor and dielectric loss in the above configuration have also been studied. Polystyrene (µ_r = 2.56) and Stycast (µ_r = 3.4) have been used as dielectric materials.     

Non-polynomial sextic spline approach for the solution of fourth-order boundary value problems

In this paper a non-polynomial sextic spline function is applied to the numerical solution of a linear fourth-order two-point boundary-value problem occurring in a plate deflection theory. We have developed a non-polynomial sextic spline, which reduces to ordinary sextic spline as θ → 0. Spline relations and error estimates are given. Direct methods of order two, four and six have been obtained. Numerical results are provided to demonstrate the superiority of our methods.     

Controlling dynamical behavior of drive-response system through linear augmentation

Unidirectionally coupled chaotic systems give rise to driver induced bistability in response system under certain parameters setting. Such a system is studied here with augmented dynamics. A linear augmentation provides a controlled dynamical behavior of response system in two different ways: augmented drive system brings the stabilization of the steady state where as augmented response system is able to control the bistability. We present a detailed analysis of Lorenz–Rössler system with linear augmentation for controlled dynamical behavior.     

A Facile Method for Nucleophilic Aromatic Substitution of Cyclic Amine

The expeditious solventless nucleophilic aromatic substitution using microwaves is described. A non-conventional synthetic procedure has been developed where basic alumina has been used as energy transfer medium under Microwave Irradiation (MW1). The results were compared with those obtained by the classical method. This rapid and environmentally benign method avoids the use of excess solvents and toxic bases usually employed in the process make this procedure very attractive for synthesis.     

HTIB-Mediated One-Pot Synthesis of Some 2-Substituted 4-Styrylthiazoles from (E)-4-Arylbut-3-en-2-ones

The reaction of (E)-4-arylbut-3-en-2-ones with [(hydroxy(tosyloxy)iodo]benzene (HTIB) followed by treatment with thioureas, thioamide, and thiobenzamide has offered a one-pot synthesis of 2-substituted 4-styrylthiazoles.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Urease Inhibitory Kinetic Studies of Various Extracts and Pure Compounds from Cinnamomum Genus

Urease is an enzyme that plays a significant role in the hydrolysis of urea into carbonic acid and ammonia via the carbamic acid formation. The resultant increase in pH leads to the onset of various pathologies such as gastric cancer, urolithiasis, hepatic coma, hepatic encephalopathy, duodenal ulcers and peptic ulcers. Urease inhibitors can reduce the urea hydrolysis rate and development of various diseases. The Cinnamomum genus is used in a large number of traditional medicines. It is well established that stem bark of Cinnamomum cassia exhibits antiulcerogenic potential. The present study evaluated the inhibitory effect of seven extracts of Cinnamomum camphora, Cinnamomum verum and two pure compounds Camphene and Cuminaldehyde on urease enzyme. Kinetic studies of potential inhibitors were carried out. Methanol extract (IC₅₀ 980 µg/mL) of C. camphora and a monoterpene Camphene (IC₅₀ 0.147 µg/mL) possess significant inhibitory activity. The Lineweaver Burk plot analysis suggested the competitive inhibition by methanol extract, hexane fraction and Camphene. The Gas Chromatography-Mass Spectroscopy (GC–MS) analysis of hexane fraction revealed the contribution of various terpenes. The present study targets terpenes as a new class of inhibitors that have potential therapeutic value for further development as novel drugs.     

Analysis of salt stress induced changes in Photosystem II heterogeneity by prompt fluorescence and delayed fluorescence in wheat (Triticum aestivum) leaves

In order to investigate changes in the heterogeneity of PSII, prompt fluorescence induction curves (PFIC) and delayed fluorescence induction curves (DFIC) were measured in wheat leaves after salt treatment. From these data, antenna heterogeneity and reducing side heterogeneity were estimated. Results show that antenna size, which is further differentiated into α, β and γ PSII centers, is changed under salt stress conditions. At higher salt concentration, there is a decrease in the number of α PSII centers with simultaneous increase in the amount of β and γ PSII centers. Another aspect of antenna heterogeneity is explained in terms of connectivity (or grouping) between PSII centers which did not change significantly under salt stress. Reducing side heterogeneity was assessed by both DFIC and PFIC and results show that a significant increase in the conversion of Q(B)-reducing centers to Q(B)-non-reducing centers is observed under salt stress.     

Green chemistry-mediated synthesis of nanostructures of afterglow phosphor

Various nanostructures of SrAl₂O₄:Eu²⁺, Dy³⁺ (SAC) afterglow phosphor were prepared in a single-step reaction using a green chemistry-mediated modified combustion process. The evolution of hazardous NxOx gases during the customary combustion reaction was completely eliminated by employing an innovative complex formation route. Another fascinating feature of the process was that, a slight change in the processing conditions ensured the synthesis of either nanoparticles or nanowires. The photoluminescence spectrum of nanophosphor showed a slight blue shift in emission (∼511 nm) as compared to the bulk phosphor (∼520 nm). The afterglow (decay) profiles of SAC nanoparticles, nanowires and bulk phosphor were compared. The chemistry underlying the nanostructure synthesis and the probable afterglow mechanism were discussed.     

Agarwood—The Fragrant Molecules of a Wounded Tree

Agarwood, popularly known as oudh or gaharu, is a fragrant resinous wood of high commercial value, traded worldwide and primarily used for its distinctive fragrance in incense, perfumes, and medicine. This fragrant wood is created when Aquilaria trees are wounded and infected by fungi, producing resin as a defense mechanism. The depletion of natural agarwood caused by overharvesting amidst increasing demand has caused this fragrant defensive resin of endangered Aquilaria to become a rare and valuable commodity. Given that instances of natural infection are quite low, artificial induction, including biological inoculation, is being conducted to induce agarwood formation. A long-term investigation could unravel insights contributing toward Aquilaria being sustainably cultivated. This review will look at the different methods of induction, including physical, chemical, and biological, and compare the production, yield, and quality of such treatments with naturally formed agarwood. Pharmaceutical properties and medicinal benefits of fragrance-associated compounds such as chromones and terpenoids are also discussed.