Early supernovae light-curves following the shock-breakout

The first light from a supernova (SN) emerges once the SN shock breaks out of the stellar surface. The first light, typically a UV or X-ray flash, is followed by a broken power-law decay of the luminosity generated by radiation that leaks out of the expanding gas sphere. Motivated by recent detection of emission from very early stages of several SNe, we revisit the theory of shock breakout and the following emission. We derive analytic light curves, paying special attention to the photon-gas coupling and deviations from thermal equilibrium. We then consider the breakout from several SNe progenitors. We find that for more compact progenitors, white dwarfs, Wolf-Rayet stars (WRs) and possibly more energetic blue-supergiant explosions, the observed radiation is out of thermal equilibrium at the breakout, during the planar phase (i.e., before the expanding gas doubles its radius), and during the early spherical phase. Therefore, during these phases we predict significantly higher temperatures than previous analysis that assumed equilibrium. When thermal equilibrium prevails, we find the location of the thermalization depth and its temporal evolution. Our results are useful for interpretation of early SN light curves. Some examples are: (i) Red supergiant SNe have an early bright peak in optical and UV flux, less than an hour after breakout. It is followed by a minimum at the end of the planar phase (about 10 hr), before it peaks again once the temperature drops to the observed frequency range. In contrast WRs show only the latter peak in optical and UV. (ii) Bright X-ray flares are expected from all core-collapse SNe types. (iii) The light curve and spectrum of the initial breakout pulse holds information on the explosion geometry and progenitor wind opacity. Its spectrum in compact progenitors shows a (non-thermal) power-law.Comment: ApJ in pres

Integration of aero-elastic belt into the built environment for low-energy wind harnessing: current status and a case study

Low-powered devices are ubiquitous in this modern age especially their application in the urban and built environment. The myriad of low-energy applications extend from wireless sensors, data loggers, transmitters and other small-scale electronics. These devices which operate in the microWatt to milliWatt power range and will play a significant role in the future of smart cities providing power for extended operation with little or no battery dependence. Low energy harvesters such as the aero-elastic belt are suitable for integration with wireless sensors and other small-scale electronic devices and therefore there is a need for studying its optimal installation conditions. In this work, a case study presenting the Computational Fluid Dynamics modelling of a building integrated with aero-elastic belts (electromagnetic transduction type) was presented. The simulation used a gable-roof type building model with a 27° pitch obtained from the literature. The atmospheric boundary layer flow was employed for the simulation of the incident wind. The work investigates the effect of various wind speeds and aero-elastic belt locations on the performance of the device giving insight on the potential for integration of the harvester into the built environment. The apex of the roof of the building yielded the highest power output for the aero-elastic belt due to flow speed-up maximisation in this region. This location produced the largest power output under the 45° angle of approach, generating an estimated 62.4 mW of power under accelerated wind in belt position of up to 6.2 m/s. For wind velocity of 10 m/s, wind in this position accelerated up to approximately 14.4 m/s which is a 37.5% speed-up at the particular height. This occurred for an oncoming wind 30° relative to the building facade. For velocity equal to 4.7 m/s under 0° wind direction, airflows in facade edges were the fastest at 5.4 m/s indicating a 15% speed-up along the edges of the building

Revisiting the Local Structure in Ge-Sb-Te based Chalcogenide Superlattices.

The technological success of phase-change materials in the field of data storage and functional systems stems from their distinctive electronic and structural peculiarities on the nanoscale. Recently, superlattice structures have been demonstrated to dramatically improve the optical and electrical performances of these chalcogenide based phase-change materials. In this perspective, unravelling the atomistic structure that originates the improvements in switching time and switching energy is paramount in order to design nanoscale structures with even enhanced functional properties. This study reveals a high- resolution atomistic insight of the [GeTe/Sb2Te3] interfacial structure by means of Extended X-Ray Absorption Fine Structure spectroscopy and Transmission Electron Microscopy. Based on our results we propose a consistent novel structure for this kind of chalcogenide superlattices

Efficient delivery of RNA Interference to peripheral neurons in vivo using herpes simplex virus

Considerable interest has been focused on inducing RNA interference (RNAi) in neurons to study gene function and identify new targets for disease intervention. Although small interfering RNAs (siRNAs) have been used to silence genes in neurons, in vivo delivery of RNAi remains a major challenge limiting its applications. We have developed a highly efficient method for in vivo gene silencing in dorsal root ganglia (DRG) using replication-defective herpes simplex viral (HSV-1) vectors. HSV-mediated delivery of short-hairpin RNA (shRNA) targeting reporter genes resulted in highly effective and specific silencing in neuronal and non-neuronal cells in culture and in the DRG of mice in vivo including in a transgenic mouse model. We further establish proof of concept by demonstrating in vivo silencing of the endogenous trpv1 gene. These data are the first to show silencing in DRG neurons in vivo by vector-mediated delivery of shRNA. Our results support the utility of HSV vectors for gene silencing in peripheral neurons and the potential application of this technology to the study of nociceptive processes and in pain gene target validation studies

Important prognostic factors for the long-term survival of lung cancer subjects in Taiwan

<p>Abstract</p> <p>Background</p> <p>This study used a large-scale cancer database in determination of prognostic factors for the survival of lung cancer subjects in Taiwan.</p> <p>Methods</p> <p>Total of 24,910 subjects diagnosed with lung cancer was analysed. Survival estimates by Kaplan-Meier methods. Cox proportional-hazards model estimated the death risk (hazard ratio (HR)) for various prognostic factors.</p> <p>Results</p> <p>The prognostic indicators associated with a higher risk of lung cancer deaths are male gender (males versus females; HR = 1.07, 95% confidence intervals (CI): 1.03–1.11), males diagnosed in later periods (shown in 1991–1994 versus 1987–1990; HR = 1.13), older age at diagnosis, large cell carcinoma (LCC)/small cell carcinoma (SCC), and supportive care therapy over chemotherapy. The overall 5-year survival rate for lung cancer death was significantly poorer for males (21.3%) than females (23.6%). Subjects with squamous cell carcinoma (SQCC) and treatment by surgical resection alone had better prognosis. We find surgical resections to markedly increase 5-year survival rate from LCC, decreased risk of death from LCC, and no improved survival from SCC.</p> <p>Conclusion</p> <p>Gender and clinical characteristics (i.e. diagnostic period, diagnostic age, histological type and treatment modality) play important roles in determining lung cancer survival.</p

Risk for Progression to Overt Hypothyroidism in an Elderly Japanese Population with Subclinical Hypothyroidism

Background: Few population-based studies report the changes with time in thyroid function tests in patients with subclinical hypothyroidism. We compared the risk for developing overt hypothyroidism in patients with subclinical hypothyroidism and euthyroid controls from the same population of elderly Japanese. We also sought associations of selected parameters with the development of overt hypothyroidism in the subclinical hypothyroid and euthyroid groups. Methods: We measured thyrotropin (TSH) and free thyroxine (T4) levels at baseline examinations performed from 2000 to 2003 in the cohort of Japanese atomic-bomb survivors and identified 71 patients with spontaneous subclinical hypothyroidism (normal free T4 and TSH >4.5 mIU/L without a history of thyroid treatment, mean age 70 year) and 562 euthyroid controls. We re-examined TSH and free T4 levels an average of 4.2 years later (range, 1.9-6.9). Results: The risk for progression to overt hypothyroidism was significantly increased in subclinical hypothyroid patients (7.0%) compared with control subjects (1.6%) after adjusting for age and sex (odds ratio, 4.56; p=0.009). Higher baseline TSH levels were associated with progression from subclinical to overt hypothyroidism (p=0.02) in the multivariate analysis, including age, sex, antithyroid peroxidase antibody, and ultrasonography (US) findings. The analysis using binary TSH data suggested that a TSH level >8 mIU/L was a predictive value for development of overt hypothyroidism (p=0.005). On the other hand, serum TSH levels spontaneously normalized in 38 (53.5%) of the patients with subclinical hypothyroidism. In the multivariate analysis, normalization of TSH levels was associated with lower baseline TSH levels (p=0.004) and normal and homogenous thyroid US findings (p=0.04). Atomic-bomb radiation dose was not associated with subclinical hypothyroidism or its course. Conclusions: Subclinical hypothyroidism was four times more likely to be associated with development of overt hypothyroidism than euthyroid controls in the sample population of Japanese elderly. TSH levels in half of the patients normalized spontaneously when assessed after an average follow-up period of 4.2 years. Baseline TSH level and thyroid US findings are potential predictors of future thyroid function in subclinical hypothyroidism

An overview of dealloyed nanoporous gold in bioelectrochemistry

peer-reviewedNanoporous gold (NPG) obtained via dealloying of Au alloys has potential applications in a range of fields, and in particular in bioelectrochemistry. NPG possesses a three dimensional bicontinuous network of interconnected pores with typical pore diameters of ca. 30-40 nm, features that are useful for the immobilisation of enzymes. This review describes the common routes of fabrication and characterization of NPG, the use of NPG as a support for oxidoreductases for applications in biosensors and biofuel cells together with recent progress in the use of NPG electrodes for applications in bioelectrochemistry

Photocatalytic Degradation of Organic Pollutants in Water Using Graphene Oxide Composite

Developing sustainable and less-expensive technique is always challenging task in water treatment process. This chapter explores the recent development of photocatalysis technique in organic pollutant removal from the water. Particularly, advantages of graphene oxide in promoting the catalytic performance of semiconductor, metal nanoparticle and polymer based photocatalyst materials. Owing to high internal surface area and rapid electron conducting property of graphene oxide fostering as backbone scaffold for effective hetero-photocatalyst loading, and rapid photo-charge separation enables effective degradation of pollutant. This chapter summaries the recent development of graphene oxide composite (metal oxide, metal nanoparticle, metal chalcogenides, and polymers) in semiconductor photocatalysis process towards environmental remediation application