MULTILAYER MICROSTRIP ANTENNA QUALITY FACTOR OPTIMIZATION FOR BANDWIDTH ENHANCEMENT

The impedance bandwidth, one of the important characteristics of microstrip patch antennas, can be significantly improved by using a multilayer dielectric configuration. In this paper the focus is on bandwidth enhancement technique of a multilayer patch antenna for X-band applications. In order to enhance the bandwidth, antenna losses are contained by controlling those quality factors which can have a significant impact on the bandwidth for a given permittivity and thickness of the substrate. This has been achieved by conformal transformation of the multidielectric microstrip antenna. For the ease of analysis Wheelers transformation is used to map the complex permittivity of a multilayer substrate to a single layer. Method of Moments and Finite Difference Time Domain approaches are used for the computation of results

PLANT-BASED REMEDIES FOR THE MANAGEMENT OF DIABETES

The knowledge related to medicinal plants have been described in Indian Ayurveda System and survived till today through the prevalent socio-cultural practices. Present study is an attempt to document anti-diabetic plants from Una district of Himachal Pradesh. A thorough survey was conducted from 500 respondents using a semi-structured questionnaire and informal discussions. A total of 84 anti-diabetic plant species have been recorded. These plants include wild (32) or cultivated (41) species. Fabaceae was the dominant family with 10 species. The phytoremedies were prepared using different plant parts or sometimes even the whole plant or in combination with other species. There are only few reports on anti-diabetic use of some wild species from the study area. Further studies of bioactive compounds in these species can depict their hypoglycemic potential. Present study has suggested a strong link between traditional herbal medicines, their documentation and proper chemical characterization to harness their therapeutic potential to the maximum.  KEY WORDS: Diabetes, bioactive compounds, traditional medicines, phytoremedies, angiosperms, Una, Himachal Prades

Application of potato (Solanum tuberosum) plant wastes for the removal of methylene blue and malachite green dye from aqueous solution

AbstractDye pollutants from the textile, paper, and leather industries are important sources of environmental contamination. In the present study an agricultural waste from potato plant (potato stem powder, PSP and potato leaves powder, PLP) was used as an adsorbent for removal of the methylene blue (MB) and malachite green (MG) dyes from aqueous solution. The adsorbent materials were characterized by scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. Batch experiments were performed to investigate the effect of physico-chemical parameters, such as pHpzc, ionic strength, adsorbent dose, contact time, initial dyes concentration and temperature. The kinetics of adsorption was studied by applying the pseudo-first order, pseudo-second order and intraparticle diffusion models. The pseudo-second order model better represented the adsorption kinetics and the mechanism was controlled by surface adsorption and intraparticle diffusion. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The thermodynamic parameters such as change in enthalpy (ΔH°), entropy (ΔS°) and Gibb’s free energy (ΔG°) of adsorption systems were also determined and evaluated

Electronic damping of molecular motion at metal surfaces

A method for the calculation of the damping rate due to electron-hole pair excitation for atomic and molecular motion at metal surfaces is presented. The theoretical basis is provided by Time Dependent Density Functional Theory (TDDFT) in the quasi-static limit and calculations are performed within a standard plane-wave, pseudopotential framework. The artificial periodicity introduced by using a super-cell geometry is removed to derive results for the motion of an isolated atom or molecule, rather than for the coherent motion of an ordered over-layer. The algorithm is implemented in parallel, distributed across both ${\bf k}$ and ${\bf g}$ space, and in a form compatible with the CASTEP code. Test results for the damping of the motion of hydrogen atoms above the Cu(111) surface are presented.Comment: 10 pages, 3 figure

J/Psi suppression in colliding nuclei: statistical model analysis

We consider the $J/\Psi$ suppression at a high energy heavy ion collision. An ideal gas of massive hadrons in thermal and chemical equilibrium is formed in the central region. The finite-size gas expands longitudinally in accordance with Bjorken law. The transverse expansion in a form of the rarefaction wave is taken into account. We show that $J/\Psi$ suppression in such an environment, when combined with the disintegration in nuclear matter, gives correct evaluation of NA38 and NA50 data in a broad range of initial energy densities.Comment: 14 pages, 13 figures. Accepted for publication in Phys. Rev.

Evaluation of susceptibility testing methods for polymyxin

SummaryBackgroundThe widespread resistance in Gram-negative bacteria has necessitated evaluation of the use of older antimicrobials such as polymyxins. In the present study we evaluated the different susceptibility testing methods for polymyxins B and E against Gram-negative bacteria using the new Clinical and Laboratory Standards Institute (CLSI) guidelines.MethodsThe susceptibility of 281 multidrug-resistant (MDR) Gram-negative bacteria (GNB) to polymyxin B was evaluated, comparing broth microdilution (BMD; reference method), agar dilution, E-test, and disk diffusion. Disk diffusion testing of polymyxin B was also performed against 723 MDR GNB.ResultsTwenty-four of 281 (8.5%) isolates were found to be resistant to polymyxin B by the reference BMD method. The rates of very major errors for agar dilution and E-test (for polymyxin B) were 0.7% and 1%, respectively, and those for disk diffusion (for polymyxin B and polymyxin E) were 1% and 0.7%, respectively. For the 257 isolates found sensitive by reference BMD, the rates of major errors by agar dilution and E-test (for polymyxin B) were 2.4% and 0%, respectively, and those for disk diffusion (polymyxin B and polymyxin E) were 0% and 0.7%, respectively. Twenty-six (3.6%) of the 723 Gram-negative isolates were resistant to polymyxin B by disk diffusion.ConclusionThe E-test and agar dilution methods showed good concordance with BMD. The disk diffusion method can be useful for initial screening in diagnostic laboratories

Tight-binding g-Factor Calculations of CdSe Nanostructures

The Lande g-factors for CdSe quantum dots and rods are investigated within the framework of the semiempirical tight-binding method. We describe methods for treating both the n-doped and neutral nanostructures, and then apply these to a selection of nanocrystals of variable size and shape, focusing on approximately spherical dots and rods of differing aspect ratio. For the negatively charged n-doped systems, we observe that the g-factors for near-spherical CdSe dots are approximately independent of size, but show strong shape dependence as one axis of the quantum dot is extended to form rod-like structures. In particular, there is a discontinuity in the magnitude of g-factor and a transition from anisotropic to isotropic g-factor tensor at aspect ratio ~1.3. For the neutral systems, we analyze the electron g-factor of both the conduction and valence band electrons. We find that the behavior of the electron g-factor in the neutral nanocrystals is generally similar to that in the n-doped case, showing the same strong shape dependence and discontinuity in magnitude and anisotropy. In smaller systems the g-factor value is dependent on the details of the surface model. Comparison with recent measurements of g-factors for CdSe nanocrystals suggests that the shape dependent transition may be responsible for the observations of anomalous numbers of g-factors at certain nanocrystal sizes.Comment: 15 pages, 6 figures. Fixed typos to match published versio

Electronic Raman scattering and photoluminescence from La0.7_{0.7}Sr0.3_{0.3}MnO3_3 exhibiting giant magnetoresistance

Raman and Photoluminescence (PL) experiments on correlated metallic La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ have been carried out using different excitation wavelengths as a function of temperature from 15 K to 300 K. Our data suggest a Raman mode centered at 1800 cm$^{-1}$ and a PL band at 2.2 eV. The intensities of the two peaks decrease with increasing temperature. The Raman mode can be attributed to a plasmon excitation whose frequency and linewidths are consistent with the measured resistivities. The PL involves intersite electronic transitions of the manganese ions.Comment: 10 pages + 4 eps figures, Revtex 3.0, figures available on reques