Self-improving properties of a generalized Muckenhoupt class

Acta Mathematica Hungarica - We first prove some new weighted refinements of inequalities of Hardy’s type with negative powers. Next, we prove that any $$A_{\lambda }^{1}$$ Muckenhoupt class...     

Optical properties of Cantor nanostructures made from porous silicon: A sensing application

The fabrication and characterization of pSi based triadic Cantor multilayer structures is reported. Transfer matrix method was used to calculate the corresponding reflectivity spectrum and was compared with the experimental data. A good agreement between the theoretical and experimental reflectivity spectra is reported for the wavelengths corresponding to the non-absorbing region for silicon. The reduction in the quality of the transmission modes has been attributed to the dispersion and backscattering from the interfaces of the complete structure. As the optical response of pSi based sensor depends on the characteristics of the multilayered photonic structure, a comparison of sensitivity of 3rd order Cantor structure with a regular microcavity structure of similar optical thickness resulted in an optical response dependent on the choice of the refractive indices. An optimal choice of the refractive indices for the Cantor structures resulted in an increased red-shift (due to the enhancement of the refractive indices of the corresponding layers), after the surface modification of the photonic device. Such structures offer the possibility to improve the sensing response of the pSi-based photonic structures.     

Functionalization of Cotton by In-Situ Reaction of Styrene in Atmospheric Pressure Plasma Zone

Cotton fabric was treated using styrene/helium glow plasma at the atmospheric pressure. After the treatment, the substrate was found to turn into a highly hydrophobic material showing water drop disappearance time of 60?min and water contact angle of 133°. The treatment was found to be durable even after vigorous washing. The effect of various parameters, such as discharge voltage and frequency, on fragmentation of styrene inside plasma zone was investigated using optical emission spectroscopy and GC?CMS. The types of fragments formed in the plasma zone were correlated with the hydrophobicity of the substrate. The chemical nature of surface of the substrate was analyzed using SEM and Raman spectroscopy to elucidate the possible mechanism of plasma modification.     

DC electrical conduction and morphological behavior of counter anion‐governed genesis of electrochemically synthesized polypyrrole films

Highly conducting polypyrrole (PPY) films, doped with various anions [pTS^?, ClO₄^?, and NO₃^? and mixed electrolyte system (pTS^? + ClO₄^?)], have been electrochemically synthesized in aqueous solution at ～275 K in an inert atmosphere. PPY exhibits metallic order dc conductivity at room temperature and shows variation of conductivity with respect to time of polymerization. Effect of dopant anion on growth mechanism of PPY is evident from its surface morphology. X‐ray photoelectron spectroscopy (XPS), used to examine the surface composition and doping level of various PPY films, confirms the anionic doping into the polymer backbone. Both XPS and ultraviolet–visible spectroscopy give evidence of formation of polarons and bipolarons. The temperature (4.2–320 K)‐dependent dc conductivity data of these PPY films have been explained by Mott's 3D variable‐range hopping conduction model. Mott's parameters have been estimated, and structural disorder with doping is correlated for all the samples. Mott's criterion for distant hopping sites prevails in case of moderately doped samples (PPY3, PPY4, and PPY5), whereas the hopping to nearest neighbor sites is found more suitable in case of highly doped samples (PPY1 and PPY2). The origin of these changes is due to the modification in the molecular structure of PPY, which is governed by different growth mechanisms for organic (pTS^?) and inorganic (ClO₄^? and NO₃^?) counter anions. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Design,synthesis of novel N prenylated indole-3-carbazones and evaluation of in vitro cytotoxicity and 5-LOX inhibition activities

A series of novel N-1 and C-3 substituted indole derivatives (5a–f) were designed, synthesized and evaluated for their cytotoxic properties, viz Brine Shrimp Lethality Bioassay (BSLB) besides 5-Lipoxygenase (5-LOX) inhibitory activities through in vitro assays. Structure Activity Relation (SAR) studies showed that compound 5d with an LC₅₀ of 6.49 μM and 5c with an IC₅₀ of 33.69 μM were found to be interesting for cytotoxicity and 5-LOX inhibitory activity respectively.     

Quantification of rosiglitazone in rat plasma and tissues via LC–MS/MS: Method development,validation, and application in pharmacokinetic and tissue distribution studies

A bioanalytical method for the quantification of rosiglitazone in rat plasma and tissues (adipose tissue, heart, brain, bone, and kidney) using LC–MS/MS was developed and validated. Chromatographic separation was achieved on a Gemini C₁₈ column (50 × 4.6 mm, 3 μm) using a mobile phase consisting of 10 mM ammonium formate (pH 4.0) and acetonitrile (10:90, v/v) at a flow rate of 0.8 mL/min and injection volume of 10 μL (internal standard: pioglitazone). LC–MS detection was performed with multiple reaction monitoring mode using target ions at m/z → 358.0 and m/z → 357.67 for rosiglitazone and pioglitazone (internal standard), respectively. The calibration curve showed a good correlation coefficient (r²) over the concentration range of 1–10,000 ng/mL. The mean percentage recoveries of rosiglitazone were found to be over the range of 92.54–96.64%, with detection and lower quantification limit of 0.6 and 1.0 ng/mL, respectively. The developed method was validated per U.S. Food and Drug Administration guidelines and successfully utilized to measure rosiglitazone in plasma and tissue samples. Further, the developed method can be utilized for validating specific organ-targeting delivery systems of rosiglitazone in addition to conventional dosage forms.     

Polypyrrole Coated Multiwalled Carbon Nanotube Hybrids for Corrosion Inhibition

Colloid Journal - The present study highlights the suitability of multiwalled carbon nanotube (MWCNT) incorporated polypyrrole (PPy) nanohybrids for corrosion inhibition applications. These...     

Homotopy Perturbation Method for Time-Fractional Shock Wave Equation

A scheme is developed to study numerical solution of the time-fractional shock wave equation and wave equation under initial conditions by the homotopy perturbation method (HPM). The fractional derivatives are taken in the Caputo sense. The solutions are given in the form of series with easily computable terms. Numerical results are illustrated through the graph.     

Experimental and numerical investigations of impacting cantilever beams part 1: first mode response

In this paper, the dynamic behavior of a cantilever beam impacting two flexible stops as well as rigid stops is studied both experimentally and numerically. The effect of contact stiffness, clearance, and contacting materials is studied in detail. For the numerical study of the system, a finite element model is created and the resulting differential equations are solved using a Time Variational Method (TVM). To achieve higher computational efficiency, the Newton–Krylov method is used along with TVM. Experimental results validate the contact model proposed for predicting the first mode system dynamics. A new nonlinear force estimation function has been proposed based on measured accelerations, which enables the understanding of the impact dynamics.     

Transport property measurements in tungsten sulphoselenide single crystals grown by a CVT technique

The transport properties of ternary mixed WS_xSe_2‐x single crystals have been studied by measuring the thermo power, electrical conductivities and Hall parameters in a small temperature range 303‐423 K. The electrical conductivity was highest for selenium rich WSe₂ and lowest for sulphur rich WS₂ crystals. All the crystals showed semiconducting behaviour from the temperature dependence of ‘ρ’, ‘R_H’ and ‘S’. The Hall coefficients showed that the samples are p‐type conducting. The temperature dependence of resistivity, Hall coefficients, carrier concentration showed that all of them are thermally activated. The values of activation energies, pre‐exponential factors and the scattering parameters have been determined. The dominant scattering mechanism for the charge carriers has been explained. The relation between the TEP and the concentration of charge carriers and electrical conductivity was studied. The effective masses of holes and the effective density of states have been determined. These parameters show an increase with increase in sulphur content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)