Advanced Compton Telescope Designs and SN Science

The Advanced Compton Telescope (ACT) has been suggested to be the optimal next-generation instrument to study nuclear gamma-ray lines. In this work, we investigate the potential of three hypothetical designs of the ACT to perform SN science. We provide estimates of 1) the SN detection rate, 2) the SN Ia discrimination rate, and 3) which gamma-ray lines would be detected from specific supernova remnants. We find that the prompt emission from a SN Ia is such that it is unlikely that one would be within the range that an INTERMEDIATE ACT would be able to distinguish between explosion scenarios, although such an instrument would detect a handful of SNRs. We further find that the SUPERIOR ACT design would be a truly breakthrough instrument for SN science. By supplying these estimates, we intend to assist the gamma-ray astrophysics community in deciding the course of the next decade of gamma-ray SN science.Comment: 10 pages, accepted for publication in New astronomy Reviews (Astronomy with Radioactivities III

Development of triamcionolone based lipid nanocapsules as platforms for ocular drug delivery

Purpose Triamcinolone acetonide (TAA) is considered a first-line drug by itself or as a combined treatment of several intraocular diseases such as macular edema, retinal vein thrombosis, uveitis and age-related macular degeneration. The development of TAA dosage forms is limited due to its poor solubility in water and physiologically acceptable solvents. Lipid nanocapsules (LNCs) are biocompatible systems that allow loading both hydrophobic and hydrophilic drugs. LNCs present a versatile composition and application suitable for different routes of administration. The aim of this work was to develop and characterize a novel lipid LNCs formulation containing TAA as drug delivery system. Methods LNCs were prepared in triplicate using an optimized phase inversion-based method described by Heurtault et al., 2002. Due to the poor solubility of TAA in the oily phase of the original formulation, two co-surfactants (captex® 500p -Glyceryl triacetate and oleic acid) in three proportions (20, 30 and 50%) were tested. The average particle size (APS), polydispersity index (PI), zeta potential (ZP) and entrapment efficacy (EE) were measured. Results Acceptable results were obtained with a 20% of both co-surfactants. LNCs with captex® 500p leads to about (40±1) nm size nanoparticles with a narrow size distribution (PI less than 0.2), a negative ZP (-1.2±0.7) mV and EE (85.8±0.8) % while LNCs with oleic acid showed an APS of (35.9± 0.6) nm and a PI below 0.1 with a negative ZP (-3.6±0.6) mV and EE (87±2) %. Moreover, both systems were stable for two months. Conclusions LNCs allow encapsulation of TAA and their properties remain constant over long periods of time. Thus, LNCs are promising systems than may be a potential strategy to improve efficacy and decrease side effects of this drug so used in the treatment of intraocular diseases

Interacting Kasner-type cosmologies

It is well known that Kasner-type cosmologies provide a useful framework for analyzing the three-dimensional anisotropic expansion because of the simplification of the anisotropic dynamics. In this paper relativistic multi-fluid Kasner-type scenarios are studied. We first consider the general case of a superposition of two ideal cosmic fluids, as well as the particular cases of non-interacting and interacting ones, by introducing a phenomenological coupling function $q(t)$. For two-fluid cosmological scenarios there exist only cosmological scaling solutions, while for three-fluid configurations there exist not only cosmological scaling ones, but also more general solutions. In the case of triply interacting cosmic fluids we can have energy transfer from two fluids to a third one, or energy transfer from one cosmic fluid to the other two. It is shown that by requiring the positivity of energy densities there always is a matter component which violates the dominant energy condition in this kind of anisotropic cosmological scenarios.Comment: Accepted for publication in Astrophysics &Space Science, 8 page

Aspects of electrostatics in a weak gravitational field

Several features of electrostatics of point charged particles in a weak, homogeneous, gravitational field are discussed using the Rindler metric to model the gravitational field. Some previously known results are obtained by simpler and more transparent procedures and are interpreted in an intuitive manner. Specifically: (i) We show that the electrostatic potential of a charge at rest in the Rindler frame is expressible as A_0=(q/l) where l is the affine parameter distance along the null geodesic from the charge to the field point. (ii) We obtain the sum of the electrostatic forces exerted by one charge on another in the Rindler frame and discuss its interpretation. (iii) We show how a purely electrostatic term in the Rindler frame appears as a radiation term in the inertial frame. (In part, this arises because charges at rest in a weak gravitational field possess additional weight due to their electrostatic energy. This weight is proportional to the acceleration and falls inversely with distance -- which are the usual characteristics of a radiation field.) (iv) We also interpret the origin of the radiation reaction term by extending our approach to include a slowly varying acceleration. Many of these results might have possible extensions for the case of electrostatics in an arbitrary static geometry. [Abridged Abstract]Comment: 26 pages; accepted for publication in Gen.Rel.Gra

Antioxidant and antimicrobial films based on brewers spent grain arabinoxylans, nanocellulose and feruloylated compounds for active packaging

In this study, brewers spent grain (BSG) arabinoxylans-based nanocomposite films were prepared by solvent casting of arabinoxylans (AX) suspensions containing different amounts of nanofibrillated cellulose (NFC, 5, 10, 25, 50 and 75% mass fraction). The obtained nanocomposite films were homogeneous and presented thermal stability up to 230 °C and good mechanical properties (Young's modulus up to 7.5 GPa). Additionally, the films with 50% NFC were loaded with ferulic acid or feruloylated arabinoxylo-oligosaccharides enriched fraction from BSG (75 mg per g of film). This combination enhanced the UV–Vis barrier properties and imparted additional functionalities to the films, namely (i) antioxidant activity up to 90% (DPPH scavenging activity), (ii) antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, and (iii) antifungal activity towards the polymorphic fungus Candida albicans. Therefore, these fully biobased nanocomposite films show potential for application as active food packaging systems.publishe

Experimental feasibility of measuring the gravitational redshift of light using dispersion in optical fibers

This paper describes a new class of experiments that use dispersion in optical fibers to convert the gravitational frequency shift of light into a measurable phase shift or time delay. Two conceptual models are explored. In the first model, long counter-propagating pulses are used in a vertical fiber optic Sagnac interferometer. The second model uses optical solitons in vertically separated fiber optic storage rings. We discuss the feasibility of using such an instrument to make a high precision measurement of the gravitational frequency shift of light.Comment: 11 pages, 12 figure

Recommendations for The Conduct of Economic Evaluations in Osteoporosis: Outcomes of An Experts’ Consensus Meeting Organized by The European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) And the US Branch of The International Osteoporosis Foundation

Summary Economic evaluations are increasingly used to assess the value of health interventions, but variable quality and heterogeneity limit the use of these evaluations by decision-makers. These recommendations provide guidance for the design, conduct, and reporting of economic evaluations in osteoporosis to improve their transparency, comparability, and methodologic standards. Introduction This paper aims to provide recommendations for the conduct of economic evaluations in osteoporosis in order to improve their transparency, comparability, and methodologic standards. Methods A working group was convened by the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis to make recommendations for the design, conduct, and reporting of economic evaluations in osteoporosis, to define an osteoporosis-specific reference case to serve a minimum standard for all economic analyses in osteoporosis, to discuss methodologic challenges and initiate a call for research. A literature review, a face-to-face meeting in New York City (including 11 experts), and a review/approval by a larger group of experts worldwide (including 23 experts in total) were conducted. Results Recommendations on the type of economic evaluation, methods for economic evaluation, modeling aspects, base-case analysis and population, excess mortality, fracture costs and disutility, treatment characteristics, and model validation were provided. Recommendations for reporting economic evaluations in osteoporosis were also made and an osteoporosis-specific checklist was designed that includes items to report when performing an economic evaluation in osteoporosis. Further, 12 minimum criteria for economic evaluations in osteoporosis were identified and 12 methodologic challenges and need for further research were discussed. Conclusion While the working group acknowledges challenges and the need for further research, these recommendations are intended to supplement general and national guidelines for economic evaluations, improve transparency, quality, and comparability of economic evaluations in osteoporosis, and maintain methodologic standards to increase their use by decision-makers

Quercus suber and Betula pendula outer barks as renewable sources of oleochemicals: A comparative study

A comparative study on the chemical composition of oak cork (Quercus suber L.) and corresponding industrial residues and birch (Betula pendula L.) outer bark is reported. Cork oak samples have lower extractives contents (6-9%) and higher contents of carbohydrates and lignin (23-27 and 33-38%, respectively) than those found for birch outer bark (40, 6 and 9%, respectively); suberin contents accounted for around 30% of cork, 11% of industrial cork powder and 45% of birch outer bark. Analysis of the suberin monomeric composition revealed that C18 and C22 omega-hydroxyfatty acids (including mid-chain epoxy- and dihydroxy-derivatives), followed by alpha,omega-dicarboxylic acids, are the main components in both suberins, with 9,10-epoxy-18-hydroxyoctadecanoic, 18-hydroxyoctadec-9-enoic, 9,10,18-trihydroxyoctadecanoic and octadec-9-enoic acids as the major components. The differences in the relative amounts of these acids in the suberin samples and the impact on the potential exploitation of the different industrial by-products are discussed. (C) 2008 Elsevier B.V All rights reserved.WaCheUp project - STRP 013896EC/6FP - priority 3, NM

The First Magnetic Fields

We review current ideas on the origin of galactic and extragalactic magnetic fields. We begin by summarizing observations of magnetic fields at cosmological redshifts and on cosmological scales. These observations translate into constraints on the strength and scale magnetic fields must have during the early stages of galaxy formation in order to seed the galactic dynamo. We examine mechanisms for the generation of magnetic fields that operate prior during inflation and during subsequent phase transitions such as electroweak symmetry breaking and the quark-hadron phase transition. The implications of strong primordial magnetic fields for the reionization epoch as well as the first generation of stars is discussed in detail. The exotic, early-Universe mechanisms are contrasted with astrophysical processes that generate fields after recombination. For example, a Biermann-type battery can operate in a proto-galaxy during the early stages of structure formation. Moreover, magnetic fields in either an early generation of stars or active galactic nuclei can be dispersed into the intergalactic medium.Comment: Accepted for publication in Space Science Reviews. Pdf can be also downloaded from http://canopus.cnu.ac.kr/ryu/cosmic-mag1.pd