Excitatory amino acid transporters in physiology and disorders of the central nervous system

Excitatory amino acid transporters (EAATs) encompass a class of five transporters with distinct expression in neurons and glia of the central nervous system (CNS). EAATs are mainly recognized for their role in uptake of the amino acid glutamate, the major excitatory neurotransmitter. EAATs-mediated clearance of glutamate released by neurons is vital to maintain proper glutamatergic signalling and to prevent toxic accumulation of this amino acid in the extracellular space. In addition, some EAATs also act as chloride channels or mediate the uptake of cysteine, required to produce the reactive oxygen speciesscavenger glutathione. Given their central role in glutamate homeostasis in the brain, as well as their additional activities, it comes as no surprise that EAAT dysfunctions have been implicated in numerous acute or chronic diseases of the CNS, including ischemic stroke and epilepsy, cerebellar ataxias, amyotrophic lateral sclerosis, Alzheimer´s disease and Huntington´s disease. Here we review the studies in cellular and animal models, as well as in humans that highlight the roles of EAATs in the pathogenesis of these devastating disorders. We also discuss the mechanisms regulating EAATs expression and intracellular trafficking and new exciting possibilities to modulate EAATs and to provide neuroprotection in course of pathologies affecting the CNS

Productivity and economic evaluation of Willow (Salix alba L.) based silvopastoral agroforestry system in Kashmir valley

Performance of two fodder crops namely, sorghum (Sorghum vulgare L.) and maize (Zea mays L.) was investigated with Willow (Salix alba L.) to evaluate productivity and economics of the silvopastoral agroforestry system in Kashmir valley. The experiment was laid out by planting two year old willows at 2.0m × 2.0m spacing and dividing the main plot into sub-plots of size 8m × 2m each with 5 replications in randomized block design (RDB). The intercrops of sorghum and maize were maintained at 20cm × 10 cm spacing and supplied with recommended doses of fertilizers. The economics of the willow plantation intercropped with fodder crops was compared with sole willow farming by the benefit-cost ratio and net present worth. The study revealed the differential behaviour of Salix alba regarding growth parameters (height, diameter and girth) by different intercrops and various fodder intercrops with respect to yield, above ground biomass, dry matter production and soil nutrient status (pH, organic carbon, available nitrogen, phosphorus and potassium). The willow based silvopastoral system was estimated to have benefit-cost ratio of 2.71 with maize and 2.68 with sorghum, while as sole crop the willows accrued a benefit-cost ratio of 2.66. The study is useful in discovering growth of willows, productivity of fodder crops and soil nutrient status under various silvopastoral agroforestry systems for maximizing economic gains. The findings envisaged evidences in favour of adopting willow based silvopastoral agroforestry instead of sole tree farming and the knowledge of interactions will be helpful in proper management of the system for sustained multiple productions

Practical tools for third order cosmological perturbations

We discuss cosmological perturbation theory at third order, deriving the gauge transformation rules for metric and matter perturbations, and constructing third order gauge invariant quantities. We present the Einstein tensor components, the evolution equations for a perfect fluid, and the Klein-Gordon equation at third order, including scalar, vector and tensor perturbations. In doing so, we also give all second order tensor components and evolution equations in full, exhilarating generality.Comment: 17 pages, revtex4; v2: corresponds to version published in JCA

Primordial black hole production due to preheating

During the preheating process at the end of inflation the amplification of field fluctuations can lead to the amplification of curvature perturbations. If the curvature perturbations on small scales are sufficiently large, primordial black holes (PBHs) will be overproduced. In this paper we study PBH production in the two-field preheating model with quadratic inflaton potential. We show that for many values of the inflaton mass m, and coupling g, small scale perturbations will be amplified sufficiently, before backreaction can shut off preheating, so that PBHs will be overproduced during the subsequent radiation dominated era.Comment: 5 pages, 3 eps figures. Minor changes to match version to appear in PRD as a rapid communicatio

Generalized Assisted Inflation

We obtain a new class of exact cosmological solutions for multi-scalar fields with exponential potentials. We generalize the assisted inflation solutions previously obtained, and demonstrate how they are modified when there exist cross-couplings between the fields, such as occur in supergravity inspired cosmological models.Comment: 5 page

Development of visible light-responsive mono and codoped TiO2 for photocatalytic degradation of methyl orange dye

Titanium dioxide (TiO2) has been acknowledged as a promising photocatalyst in environmental remediation including wastewater treatment. In this study, TiO2 nanoparticles either by single or co-doped of iron (Fe) and nitrogen (N) via sol-gel method and calcined at 500 °C for 3 hours. This experiment investigated the performance of mono/co-dopant of TiO2 photocatalyst against methyl orange in aqueous solution under UV light irradiation. The experimental results showed the rate of degradation favored in co-doped TiO2 followed by mono doped TiO2 and pristine TiO2. The photocatalytic reaction followed pseudo first-order kinetics which were rationalized in terms of the Langmuir– Hinshelwood model and provided nearly complete degradatio

SORCS1 and SORCS3 control energy balance and orexigenic peptide production

SORCS1 and SORCS3 are two related sorting receptors expressed in neurons of the arcuate nucleus of the hypothalamus. Using mouse models with individual or dual receptor deficiencies, we document a previously unknown function of these receptors in central control of metabolism. Specifically, SORCS1 and SORCS3 act as intracellular trafficking receptors for tropomyosin-related kinase B to attenuate signaling by brain-derived neurotrophic factor, a potent regulator of energy homeostasis. Loss of the joint action of SORCS1 and SORCS3 in mutant mice results in excessive production of the orexigenic neuropeptide agouti-related peptide and in a state of chronic energy excess characterized by enhanced food intake, decreased locomotor activity, diminished usage of lipids as metabolic fuel, and increased adiposity, albeit at overall reduced body weight. Our findings highlight a novel concept in regulation of the melanocortin system and the role played by trafficking receptors SORCS1 and SORCS3 in this process

Bulk Etch Rate Measurements and Calibrations of Plastic Nuclear Track Detectors

New calibrations of CR39 and Makrofol nuclear track detectors have been obtained using 158 A GeV Pb (82+) and In (49+) ions; a new method for the bulk etch rate determination, using both cone height and base diameter measurements was developed. The CR39 charge resolution based on the etch-pit base area measurement is adequate to identify nuclear fragments in the interval 7 <= Z/beta <= 49. For CR39 the detection threshold is at REL~50 MeV cm^2/g, corresponding to a nuclear fragment with Z/beta~7. Base cone area distributions for Makrofol foils exposed to Pb (82+) ions have shown for the first time all peaks due to nuclear fragments with Z > 50; the distribution of the etched cone heights shows well separated individual peaks for Z/beta = 78 - 83 (charge pickup). The Makrofol detection threshold is at REL 2700 MeV cm^2/g, corresponding to a nuclear fragment with Z/beta~50.Comment: 11 pages, 5 EPS figures. Submitted to Nucl. Instr. Meth.

Multiple field inflation

Inflation offers a simple model for very early evolution of our Universe and the origin of primordial perturbations on large scales. Over the last 25 years we have become familiar with the predictions of single-field models, but inflation with more than one light scalar field can alter preconceptions about the inflationary dynamics and our predictions for the primordial perturbations. I will discuss how future observational data could distinguish between inflation driven by one field, or many fields. As an example, I briefly review the curvaton as an alternative to the inflaton scenario for the origin of structure.Comment: 27 pages, no figures. To appear in proceedings of 22nd IAP Colloquium, Inflation +25, Paris, June 200

Dynamics and perturbations in assisted chaotic inflation

On compactification from higher dimensions, a single free massive scalar field gives rise to a set of effective four-dimensional scalar fields, each with a different mass. These can cooperate to drive a period of inflation known as assisted inflation. We analyze the dynamics of the simplest implementation of this idea, paying particular attention to the decoupling of fields from the slow-roll regime as inflation proceeds. Unlike normal models of inflation, the dynamics does not become independent of the initial conditions at late times. In particular, we estimate the density perturbations obtained, which retain a memory of the initial conditions even though a homogeneous, spatially-flat Universe is generated.Comment: 10 pages, revtex, 2 figure