Sustaining supercooled mixed phase via resonant oscillations of the order parameter

We investigate the dynamics of a first order transition when the order parameter field undergoes resonant oscillations, driven by a periodically varying parameter of the free energy. This parameter could be a background oscillating field as in models of pre-heating after inflation. In the context of condensed matter systems, it could be temperature $T$, or pressure, external electric/magnetic field etc. We show that with suitable driving frequency and amplitude, the system remains in a type of mixed phase, without ever completing transition to the stable phase, even when the oscillating parameter of the free energy remains below the corresponding critical value (for example, with oscillating temperature, $T$ always remains below the critical temperature $T_c$). This phenomenon may have important implications. In cosmology, it will imply prolonged mixed phase in a first order transition due to coupling with background oscillating fields. In condensed matter systems, it will imply that using oscillating temperature (or, more appropriately, pressure waves) one may be able to sustain liquids in a mixed phase indefinitely at low temperatures, without making transition to the frozen phase.Comment: 17 pages, 7 figures, Expanded version with more detail

Alleviating Urban Food Deserts: Lessons From the Literature

The goals of Healthy People 2010 are to increase the quality and years of healthy life and eliminate health disparities. Great health disparities occur in the area of nutrition, which is one of the objectives addressed in Healthy People 2010. It is well accepted that a healthy diet, including recommended amounts of fruits, vegetables, and whole grains, provides primary prevention against many chronic diseases, including obesity, diabetes, and certain cancers. Urban minority populations are the most likely to live in food deserts, which are areas with limited access to healthy foods. Research shows that the food environment plays a large role in the foods individuals have available to eat. Alleviating food desert conditions in urban areas has great public health importance because of the impact food environments have on the diet, and therefore health, of the people who reside in urban areas. Policy action can improve food retail access to fresh, healthy foods, decrease the price of these foods, and support the establishment of supermarkets and/or the improvement of existing small food retailers. Local policies that give tax breaks to supermarkets that locate in the center of food deserts might convince large food retailers to locate in these areas. Also, local policies that give grants to small food stores in urban food desert areas may persuade small food stores to offer more fresh produce. The United States could drastically reduce health disparities and make a giant leap towards achieving both of the Healthy People 2010 Goals of increasing years of healthy life and eliminating health disparities if urban food desert conditions were ameliorate

Single-Molecule Analysis of i-motif Within Self-Assembled DNA Duplexes and Nanocircles

The cytosine (C)-rich sequences that can fold into tetraplex structures known as i-motif are prevalent in genomic DNA. Recent studies of i-motif–forming sequences have shown increasing evidence of their roles in gene regulation. However, most of these studies have been performed in short single-stranded oligonucleotides, far from the intracellular environment. In cells, i-motif–forming sequences are flanked by DNA duplexes and packed in the genome. Therefore, exploring the conformational dynamics and kinetics of i-motif under such topologically constrained environments is highly relevant in predicting their biological roles. Using single-molecule fluorescence analysis of self-assembled DNA duplexes and nanocircles, we show that the topological environments play a key role on i-motif stability and dynamics. While the human telomere sequence (C3TAA)3C3 assumes i-motif structure at pH 5.5 regardless of topological constraint, it undergoes conformational dynamics among unfolded, partially folded and fully folded states at pH 6.5. The lifetimes of i-motif and the partially folded state at pH 6.5 were determined to be 6 ± 2 and 31 ± 11 s, respectively. Consistent with the partially folded state observed in fluorescence analysis, interrogation of current versus time traces obtained from nanopore analysis at pH 6.5 shows long-lived shallow blockades with a mean lifetime of 25 ± 6 s. Such lifetimes are sufficient for the i-motif and partially folded states to interact with proteins to modulate cellular processes

Experimental characterization of lithium-ion cell strain using laser sensors

The characterization of thickness change during operation of LFP/Graphite prismatic batteries is presented in this work. In this regard, current rate dependence, hysteresis behaviour between charge and discharge and correlation with phase changes are deepened. Experimental tests are carried out with a battery testing equipment correlated with optical laser sensors to evaluate swelling. Furthermore, thickness change is computed analytically with a mathematical model based on lattice parameters of the crystal structures of active materials. The results of the model are validated with experimental data. Thickness change is able to capture variations of the internal structure of the battery, referred to as phase change, characteristic of a certain state of charge. Furthermore, phase change shift is a characteristic of battery ageing. Being able to capture these properties with sensors mounted on the external surface the cell is a key feature for improving state of charge and state of health estimation in battery management system

Chitosan Curcumin Film As A Sensor For Detection of O-Nitrophenol and Fluoride Ion Using Fluoresce Quenching Technique

Curcumin was immobilized in chitosan films fabricated by solvent casting method. The amount of curcumin immobilization was more when methanol was used as a solvent to dissolve curcumin than the butanol solvent. The maximum amount of curcumin immobilized per gram of chitosan film was 0.023 g. Immobilized curcumin was not released back in water even after prolong contact of the films with water. Fluorescence intensity of the films got quenched when these films were in contact with an aqueous solution of o-nitrophenol (ONP) and sodium fluoride (NaF). The extent of quenching depended on the concentration of these attributes. Fluorescence intensity was highly pronounced even when the concentration of ONP and fluoride (FL) was as low as 2.0 x 10–6 M and 2.5 x 10–5 M, respectively. UV-vis spectroscopy could not detect 2.5 x 10–6 M ONP; similarly, ion chromatography was not sensitive towards 2.5 x 10–5 M FL. Since the extent of quenching varies linearly with the concentration of ONP and FL in aqueous solution, the Stern-Volmer equation can be used for quantification of these

Chiral Properties of QCD Vacuum in Magnetars- A Nambu-Jona-Lasinio Model with Semi-Classical Approximation

The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantizing magnetic fiels is studied using Nambu-Jona-Lasinio (NJL) model with Thomas-Fermi type semi-classical formalism. It is found that the dynamically generated light quark mass can never become zero if the Landau levels are populated and the mass increases with the increase of magnetic field strength.Comment: REVTEX 11 Pages, One .eps figure (included

Measurement of Steroid Concentrations in Brain Tissue: Methodological Considerations

It is well recognized that steroids are synthesized de novo in the brain (neurosteroids). In addition, steroids circulating in the blood enter the brain. Steroids play numerous roles in the brain, such as influencing neural development, adult neuroplasticity, behavior, neuroinflammation, and neurodegenerative diseases such as Alzheimer’s disease. In order to understand the regulation and functions of steroids in the brain, it is important to directly measure steroid concentrations in brain tissue. In this brief review, we discuss methods for the detection and quantification of steroids in the brain. We concisely present the major advantages and disadvantages of different technical approaches at various experimental stages: euthanasia, tissue collection, steroid extraction, steroid separation, and steroid measurement. We discuss, among other topics, the potential effects of anesthesia and saline perfusion prior to tissue collection; microdissection via Palkovits punch; solid phase extraction; chromatographic separation of steroids; and immunoassays and mass spectrometry for steroid quantification, particularly the use of mass spectrometry for “steroid profiling.” Finally, we discuss the interpretation of local steroid concentrations, such as comparing steroid levels in brain tissue with those in the circulation (plasma vs. whole blood samples; total vs. free steroid levels). We also present reference values for a variety of steroids in different brain regions of adult rats. This brief review highlights some of the major methodological considerations at multiple experimental stages and provides a broad framework for designing studies that examine local steroid levels in the brain as well as other steroidogenic tissues, such as thymus, breast, and prostate

Understanding of farmers' perception of climate change and adaptation strategies: A case study in Jhargram district of West Bengal, India

A study on farmers perceived prevalence of climate change, manifested by the phenomena like increasing temperature, fluctuating rainfall etc. and in the considered agro-ecological areas was conducted in Binpur II block of Jhargram district of West Bengal to assess the extent of farmers' perception about the climate change and their adaptation strategies to cope up with losses due to climate change. Results showed that the farmers' perception of climate change greatly influenced farmers' readiness to adapt climate change by considering some adjustments to their cultivation and production practices. The findings showed that the farmers' perception of climate change was at a high-level group of respondents. Results showed that 50% of respondents were optimistic with the idea that they can cope up the climate change problems if they get proper government assistance. Only about 13% of farmers perceived Government plans on climate change. Regarding the adaptation strategies, 40% of respondents followed more or less strategies, whereas most of the respondents did not adopt any strategies in this regard. &nbsp

Viscous instabilities in flowing foams: A Cellular Potts Model approach

The Cellular Potts Model (CPM) succesfully simulates drainage and shear in foams. Here we use the CPM to investigate instabilities due to the flow of a single large bubble in a dry, monodisperse two-dimensional flowing foam. As in experiments in a Hele-Shaw cell, above a threshold velocity the large bubble moves faster than the mean flow. Our simulations reproduce analytical and experimental predictions for the velocity threshold and the relative velocity of the large bubble, demonstrating the utility of the CPM in foam rheology studies.Comment: 10 pages, 3 figures. Replaced with revised version accepted for publication in JSTA