Naked Eye Chemosensor and In Vivo Chelating Activity of Iron (III) By Bromopyridine Quinoxaline (BPQ)

Journal of Fluorescence - A wide variety of medical, biomedical, and industrial applications has been reported for quinoxalines derivatives. In this work, a novel quinoxaline derivative was...     

Design and synthesis of phenoxymethybenzoimidazole incorporating different aryl thiazole-triazole acetamide derivatives as α-glycosidase inhibitors

Molecular Diversity - A novel series of phenoxymethybenzoimidazole derivatives (9a-n) were rationally designed, synthesized, and evaluated for their α-glycosidase inhibitory activity. All...     

Tailoring the optical and magnetic properties of La-BaM hexaferrites by Ni substitution

We investigate the impact of Ni insertion on the structural,optical,and magnetic properties of Ba_0.8La_0.2Fe_12-xNi_xO₁₉hexaferrites(Ni substituted La-BaM hexaferrites).Samples were prepared using the conventional co-precipitation method and sintered at 1000℃for 4 hours to assist the crystallization process.An analysis of the structure of the samples was carried out using an x-ray diffraction(XRD)spectrometer.The M-type hexagonal structure of all the samples was confirmed using XRD spectra.The lattice parameters a and c were found to be in the ranges of 5.8925±0.001 nm–5.8952±0.001 nm and 23.2123±0.001 nm–23.2219±0.001 nm,respectively.The M-type hexagonal nature of the prepared samples was also indicated by the presence of corresponding FT-IR bands and Raman modes in the FT-IR and Raman spectra,respectively.EDX results confirmed the successful synthesis of the samples according to the required stoichiometric ratio.A UV-vis spectrometer was used to record the absorption spectra of the prepared samples in the wavelength range of 200 nm–1100 nm.The optical energy bandgap of the samples was found to be in the range of 1.21 eV–3.39 eV.The M–H loops of the samples were measured at room temperature at an applied magnetic field range of 0 kOe–60 kOe.A high saturation magnetization of 99.92 emu/g was recorded in the sample with x=0 at a microwave operating frequency of 22.2 GHz.This high value of saturation magnetization is due to the substitution of La3+ions at the spin-up(12k,2a,and 2b)sites.The Ni substitution is proven to be a potential candidate for the tuning of the optical and magnetic parameters of M-type hexaferrites.Therefore,we suggest that the prepared samples are suitable for use in magneto-optic applications.     

Influence of various shapes of nanoparticles on unsteady stagnation-point flow of Cu-H2O nanofluid on a flat surface in a porous medium: A stability analysis

The nanofluid and porous medium together are able to fulfill the requirement of high cooling rate in many engineering problems. So, here the impact of various shapes of nanoparticles on unsteady stagnation-point flow of Cu-H₂O nanofluid on a flat surface in a porous medium is examined. Moreover, the thermal radiation and viscous dissipation effects are considered. The problem governing partial differential equations are converted into self-similar coupled ordinary differential equations and those are numerically solved by the shooting method. The computed results can reveal many vital findings of practical importance. Firstly, dual solutions exist for decelerating unsteady flow and for accelerating unsteady and steady flows, the solution is unique. The presence of nanoparticles affects the existence of dual solution in decelerating unsteady flow only when the medium of the flow is a porous medium. But different shapes of nanoparticles are not disturbing the dual solution existence range, though it has a considerable impact on thermal conductivity of the mixture. Different shapes of nanoparticles act differently to enhance the heat transfer characteristics of the base fluid, i.e., the water here. On the other hand, the existence range of dual solutions becomes wider for a larger permeability parameter related to the porous medium. Regarding the cooling rate of the heated surface, it rises with the permeability parameter, shape factor (related to various shapes of Cu-nanoparticles), and radiation parameter. The surface drag force becomes stronger with the permeability parameter. Also, with growing values of nanoparticle volume fraction, the boundary layer thickness (BLT) increases and the thermal BLT becomes thicker with larger values of shape factor. For decelerating unsteady flow, the nanofluid velocity rises with permeability parameter in the case of upper branch solution and an opposite trend for the lower branch is witnessed. The thermal BLT is thicker with radiation parameter. Due to the existence of dual solutions, a linear stability analysis is made and it is concluded that the upper branch and unique solutions are stable solutions.     

Predicting the Onset of Inertial Effects in Sandstone Rocks

This study presents a method to determine the onset of inertial effects at the microscopic level, to distinguish between Darcy and non-Darcy flow regions within porous media at the pore level, and to quantify the effects of retained polymer on gas mobility. Capillary pressure and polymer flood experiments were conducted using Elgin and Okesa sandstone samples. The pore-size distributions were used to study the high-velocity flow effects. A modified capillary-orifice model was used to determine the non-Darcy flow effects at the pore level, with and without residual polymer.The overall flow behavior at any flow rate may be described as the average of all contributions from the Darcy and the non-Darcy terms in all pores. Results of this study suggest that the conventional Reynolds number may lead to incorrect analysis of flow behavior when evaluating non-Darcy flow effects in porous media. The Forchheimer number, defined as the ratio of inertial forces to viscous forces, is found more adequate for analyzing microscopic flow behavior in porous media.     

Preparation of Cs2ZrO3 and Cs2ThO3 Through Sol-gel Method and Their Characterization

Cesium zirconate and cesium thorate were prepared by sol-gel method following citrate-nitrate route. The compounds were characterized by X-ray diffraction, chemical analysis and simultaneous TG-DTA. The methods of preparation of Cs₂ZrO₃ and Cs₂ThO₃ reported in literature involve difficult steps and require stringent experimental conditions for obtaining the compounds. In this work we report an easier method for the preparation of these compounds at relatively low temperature. This revised version was published online in July 2006 with corrections to the Cover Date.     

Bis(μ‐pyrrolidine‐N:N)bis(dibromoboron), [(Br)2B(pyrrolidine)2B(Br)2]

The B atoms in the title compound, C₈H₁₆B₂Br₄N₂, bridge between the two monomeric moieties, forming a (BN)₂ four‐membered ring with partial bond orders of the B—N bonds.     

Enantiomeric resolution of some imidazole antifungal agents on chiralpak WH chiral stationary phase using HPLC

Summary The enantiomeric resolution of (±)-econazole, (±)-miconazole and (±)-sulconazole was achieved on a Chiralpak WH column. The mobile phase used was hexane-2-propanol-diethylamine (400:99:1,v/v/v). The flow rates of the mobile phase used were 0.50 and 1.00 mL min⁻¹. The values of α of the resolved enantiomers of econazole, miconazole and sulconazole were in the range of 1.68 to 1.23 while the values of Rs varied from 2.42 to 1.10. The resolution of these antifungal agents on Chiralpak WH column is governed by ligand exchange mechanism. Hydrophobic interactions also play an important role for the enantiomeric resoltuion of antifungal agents on the reported CSP.     

Extended minimal flavour violating MSSM and implications for B physics

The recently reported measurements of the CP asymmetry by the BABAR and BELLE collaborations, obtained from the rate differences in the decays etc., and their charge conjugates, are in good agreement with the standard model (SM) prediction of the same, resulting from the unitarity of the CKM matrix. The so-called minimal flavour violating (MFV) supersymmetric extensions of the standard model, in which the CKM matrix remains the only flavour changing structure, predict similar to the one in the SM. With the anticipated precision in and other CP asymmetries at the B factories and hadron colliders, one hopes to pin down any possible deviation from the SM. We discuss an extension of the MFV-supersymmetric models which comfortably accommodates the current measurements of the CP asymmetry , but differs from the SM and the MFV-supersymmetric models due to an additional flavour changing structure beyond the CKM matrix. We suggest specific tests in forthcoming experiments in B physics. In addition to the CP-asymmetries in B-meson decays, such as and , and the mass difference in the system, we emphasize measurements of the radiative transition as sensitive probes of the postulated flavour changing structure. This is quantified in terms of the ratio , the isospin violating ratio , and the CP-asymmetry in the decay rates for and its charge conjugate. Interestingly, the CKM–unitarity analysis in the Extended–MFV model also allows solutions for the Wolfenstein parameter, as opposed to the SM and the MFV-supersymmetric models for which only solutions are now admissible, implying , where . Such large values of are hinted by the current measurements of the branching ratios for the decays and . Received: 20 May 2001 / Revised version: 5 August 2001 / Published online: 31 August 2001     

Majorana neutrinos and same-sign dilepton production at LHC and in rare meson decays

We discuss same-sign dilepton production mediated by Majorana neutrinos in high-energy proton–proton collisions for at the LHC energy TeV, and in the rare decays of the , and B mesons of the type . For the pp reaction, assuming one heavy Majorana neutrino of mass , we present discovery limits in the plane where are the mixing parameters. Taking into account the present limits from low-energy experiments, we show that at LHC one has sensitivity to heavy Majorana neutrinos up to a mass TeV in the dilepton channels , and , but the dilepton states will not be detectable due to the already existing constraints from neutrinoless double beta decay. We work out a large number of rare meson decays, both for the light and heavy Majorana neutrino scenarios, and argue that the present experimental bounds on the branching ratios are too weak to set reasonable limits on the effective Majorana masses. Received: 24 April 2001 / Published online: 29 June 2001