Dielectric properties of amino substituted pyridines in dilute solutions of some non-polar solvents at different temperatures

Microwave dielectric absorption and relaxation behaviour of each of 2-aminopyridine and 4-dimethylaminopyridine in non-polar solvents benzene, carbon tetrachloride and 1,4-dioxane have been studied at 303.15 K, 313.15 K and 323.15 K temperatures. X-band microwave bench operating at 9.1 GHz has been used for determination of dielectric constant (ε') and dielectric loss (ε"). The static permittivity (ε0) at 2 MHz and permittivity at optical frequency (ε∞) have also been determined. The measured values of dielectric permittivity (ε') and dielectric loss (ε") have been used to evaluate relaxation time (τ), dipole moment (μ), molar volume (Vm) and molar polarization of solute (P2). Present study suggests the existence of intra-molecular and overall rotation of the amino pyridine molecules in the non-polar solvents. The solute–solvent molecular associations have been predicted. The effect of solvent environments on the relaxation behaviour of the amino pyridines has also been discussed

Orientational and dielectric behaviour of N, N-dimethylformamide in different non-polar solvents

Dielectric behaviour of concentrated solutions of different mole fractions of N, N-dimethylformamide in various non-polar solvents has been studied using precision LCR meter with four terminal liquid dielectric test fixture over a frequency range 20 Hz to 2 MHz at 303.15 K temperature. The dielectric parameters namely dielectric constant (ε′), dielectric loss (ε″) and static dielectric constant (ε0) have been determined by capacitive measurement method. The limiting dielectric constant (ε∞) has been determined by Abbe’s refractometer for the same solutions at 303.15 K temperature. Kirkwood correlation factor geff has also been calculated using determined values of ε0 and ε∞,to gain information about the orientational behaviour of N, N-dimethylformamide in different non-polar solvent environments

Phase diagram of the disordered Bose-Hubbard model

We establish the phase diagram of the disordered three-dimensional Bose-Hubbard model at unity filling, which has been controversial for many years. The theorem of inclusions, proven in Ref. [1], states that the Bose glass phase always intervenes between the Mott insulating and superfluid phases. Here, we note that assumptions on which the theorem is based exclude phase transitions between gapped (Mott insulator) and gapless phases (Bose glass). The apparent paradox is resolved through a unique mechanism: such transitions have to be of the Griffiths type when the vanishing of the gap at the critical point is due to a zero concentration of rare regions where extreme fluctuations of disorder mimic a {\it regular} gapless system. An exactly solvable random transverse field Ising model in one dimension is used to illustrate the point. A highly non-trivial overall shape of the phase diagram is revealed with the worm algorithm. The phase diagram features a long superfluid finger at strong disorder and on-site interaction. Moreover, bosonic superfluidity is extremely robust against disorder in a broad range of interaction parameters; it persists in random potentials nearly 50 (!) times larger than the particle half-bandwidth. Finally, we comment on the feasibility of obtaining this phase diagram in cold-atom experiments, which work with trapped systems at finite temperature.Comment: 9 pages, 5 figure

Bunching Transitions on Vicinal Surfaces and Quantum N-mers

We study vicinal crystal surfaces with the terrace-step-kink model on a discrete lattice. Including both a short-ranged attractive interaction and a long-ranged repulsive interaction arising from elastic forces, we discover a series of phases in which steps coalesce into bunches of n steps each. The value of n varies with temperature and the ratio of short to long range interaction strengths. We propose that the bunch phases have been observed in very recent experiments on Si surfaces. Within the context of a mapping of the model to a system of bosons on a 1D lattice, the bunch phases appear as quantum n-mers.Comment: 5 pages, RevTex; to appear in Phys. Rev. Let

Assessment of physico- chemical properties and microbial community during composting of municipal solid waste (Viz. KItchen waste) at Jhansi City, U.P. (India)

Rapid industrialization and population explosion in India has led to the migration of people from villages to cities, which generate thousands of tons of Municipal Solid Waste (viz. Kitchen waste) MSW (Viz. KW) daily. Jhansi City is well known district of Bundelkhand region of Uttar Pradesh (India) with a geographical area of 502.75 thousand hectare. The district is situated in the South West corner of the region at 24º11' - 25º57' N latitude and 78º10' - 79º23' E longitudes. Population of Jhansi city is near about 4,79, 612. A detail study was conducted in four consecutive years to assess the potential and possibilities of MSW (Viz. KW) composting generated from Jhansi city, Uttar Pradesh. In the present study, we studied physico-chemical parameters and succession of microbial populations during composting process of MSW (Viz. KW) and found that the pH ranged between 7.1-7.9, Temperature 14-65.2°C, Organic Carbon 20-26 %, moisture content  22-66.7 %, nutrients N – 1.16 %, P – 0.04 %,  K – 0.34%, Na – 2.89 % and microbial colonies like Bacteria, fungi, and Actinomycetes were also present in large numbers.Temperature plays an important role in the growth of microbial colonies during composting of Municipal Solid waste (Viz. Kitchen Waste)

Prevalence of HPV in Oesophageal Biopsies and its Correlation with Expression Of P16INK4A

Background: The association of Human papillomavirus (HPV ) and p16INK4a is well established with cervical malignancies and has been studied in oral mucosa also. Koilocytosis, that is considered to be a hallmark of HPV infection is also seen in oesophageal mucosa. Aims: This study was designed to determine the prevalence of HPV in biopsies from inflammatory and neoplastic lesions of oesophagus and correlate it with expression of p16INK4a. Materials and Methods: The study included 102 oesophageal biopsies. Haematoxylin & Eosin stained sections were examined for morphological details including koilocytosis. Immunohistochemistry for HPV and p16INK4a were done on 50 biopsies. HPV positivity was graded and scoring for p16INK4a was done. Results: Various grades of koilocytosis was noted in 68.75%, 94.73% and 72.91% controls, inflammatory and neoplastic lesions respectively. IHC for HPV was positive in 80% control, 75% inflammatory and 100% cases of neoplastic lesion. Complete score for p16INK4a was 0.60, 0.59 and 3.63 in control, inflammatory and neoplastic lesion. The difference in expression of p16INK4a between neoplastic and inflammatory lesion was statistically significant. Conclusion: Expression of p16INK4a protein showed good correlation with HPV infection in inflammatory and neoplastic lesions. Thus IHC for p16INK4a which is easily available can be used as an indirect evidence of HPV infection in neoplastic lesion where expensive molecular technique for HPV DNA measurement is not feasibl

Electrostatic- and Parallel Magnetic Field- Tuned Two Dimensional Superconductor-Insulator Transitions

The 2D superconductor-insulator transition in disordered ultrathin amorphous bismuth films has been tuned both by electrostatic electron doping using the electric field effect and by the application of parallel magnetic fields. Electrostatic doping was carried out in both zero and nonzero magnetic fields, and magnetic tuning was conducted at multiple strengths of electrostatically induced superconductivity. The transitions were analyzed using finite size scaling with critical exponent products nu*z = 0.65-0.7. The parallel critical magnetic field increased with electron transfer as (dn_c-dn)^0.33, where dn is the electron transfer and dn_c is its critical value, and the critical resistance decreased linearly with dn. However at lower temperatures, in the insulating regime, the resistance became larger than expected from extrapolation of its temperature dependence at higher temperatures, and scaling failed. These observations imply that although the electrostatic- and parallel magnetic field- tuned superconductor-insulator transitions would appear to belong to the same universality class and to be delineated by a robust phase boundary that can be crossed either by tuning electron density or magnetic field, in the case of the field-tuned transition at the lowest temperatures, some different type of physical behavior turns on in the insulating regime.Comment: About 11 pages, with 14 figures. To be submitted to Phys Rev

On the Dynamics of Near-Extremal Black Holes

We analyse the dynamics of near-extremal Reissner-Nordstr\"om black holes in asymptotically four-dimensional Anti-de Sitter space (AdS$_4$). We work in the spherically symmetric approximation and study the thermodynamics and the response to a probe scalar field. We find that the behaviour of the system, at low energies and to leading order in our approximations, is well described by the Jackiw-Teitelboim (JT) model of gravity. In fact, this behaviour can be understood from symmetry considerations and arises due to the breaking of time reparametrisation invariance. The JT model has been analysed in considerable detail recently and related to the behaviour of the SYK model. Our results indicate that features in these models which arise from symmetry considerations alone are more general and present quite universally in near-extremal black holes.Comment: 44 (=26+18) pages, 1 figure, 6 appendices; v2: references added; v3: minor changes made; v4: additional references added, version accepted in JHE