680 research outputs found
Using Chandra to Unveil the High-Energy Properties of the High-Magnetic Field Radio Pulsar J1119-6127
(shortened) PSR J1119-6127 is a high magnetic field (B=4.1E13 Gauss), young
(<=1,700 year-old), and slow (P=408 ms) radio pulsar associated with the
supernova remnant (SNR) G292.2-0.5. In 2003, Chandra allowed the detection of
the X-ray counterpart of the radio pulsar, and provided the first evidence for
a compact pulsar wind nebula (PWN). We here present new Chandra observations
which allowed for the first time an imaging and spectroscopic study of the
pulsar and PWN independently of each other. The PWN is only evident in the hard
band and consists of jet-like structures extending to at least 7" from the
pulsar, with the southern `jet' being longer than the northern `jet'. The
spectrum of the PWN is described by a power law with a photon index~1.1 for the
compact PWN and ~1.4 for the southern long jet (at a fixed column density of
1.8E22/cm2), and a total luminosity of 4E32 ergs/s (0.5-7 keV), at a distance
of 8.4 kpc. The pulsar's spectrum is clearly softer than the PWN's spectrum. We
rule out a single blackbody model for the pulsar, and present the first
evidence of non-thermal (presumably magnetospheric) emission that dominates
above ~3keV. A two-component model consisting of a power law component (with
photon index ~1.5--2.0) plus a thermal component provides the best fit. The
thermal component can be fit by either a blackbody model with a temperature
kT~0.21 keV, or a neutron star atmospheric model with a temperature kT~0.14
keV. The efficiency of the pulsar in converting its rotational power, Edot,
into non-thermal X-ray emission from the pulsar and PWN is ~5E-4, comparable to
other rotation-powered pulsars with a similar Edot. We discuss our results in
the context of the X-ray manifestation of high-magnetic field radio pulsars in
comparison with rotation-powered pulsars and magnetars.Comment: 26 pages including 3 tables and 7 figures. Accepted for publication
in Ap
Use of grape pomace phenolics to counteract endogenous and exogenous formation of advanced glycation end-products
The increase in consumption of \u201cultra-processed\u201d foods has raised attention because of the possible adverse effects deriving from the Maillard reaction leading to the formation of toxic advanced glycation end-products (AGEs) during food processing. Additionally, the increasing trend and consumption of sugar-added foods and sweetened beverages is related to the endogenous formation of the same toxic compounds. However, ultra-processing in the context of food technology can bring challenges as well as a wealth of opportunities. Indeed, re-processing of grape pomace, a by-product of winemaking, can yield phenolic-rich fractions that efficiently counteract the effects of AGEs. In this review, the process of endogenous and exogenous AGE formation is illustrated. Then, the ability of grape phenolics to act as inhibitors of AGE formation is presented, including the efficacy ranking of various individual compounds measured in vitro and the outcome of in vivo double-blinded randomized crossover trials designed to prove the efficacy of grape phenolics as inhibitors of protein carbonylation. Finally, a survey of model functional foods added with grape phenolics, either to lower the dietary load of AGEs or to deliver antiglycation agents in vivo is listed in order to highlight the opportunity to develop safe and tailor-made \u201canti-AGEs\u201d food applications
Uterine rupture at the fundus during pregnancy: a case report
Rupture of a gravid uterus is a surgical emergency. Predisposing factors include a scarred uterus. Spontaneous rupture of an unscarred uterus during pregnancy is a rare occurrence. We hereby present the case of a spontaneous complete uterine fundal rupture at Karnataka Institute of Medical Sciences, Hubli, Karnataka, India. The patient had a history of septal resection. Spontaneous uterine rupture occurs when there is an upper segment uterine scar. This case report shows that past history of septal resection is a risk factor for the presence of uterine scar
Temperature-dependent optical properties of plasmonic titanium nitride thin films
Due to their exceptional plasmonic properties, noble metals such as gold and
silver have been the materials of choice for the demonstration of various
plasmonic and nanophotonic phenomena. However, noble metals' softness, lack of
tailorability and low melting point along with challenges in thin film
fabrication and device integration have prevented the realization of real-life
plasmonic devices.In the recent years, titanium nitride (TiN) has emerged as a
promising plasmonic material with good metallic and refractory (high
temperature stable) properties. The refractory nature of TiN could enable
practical plasmonic devices operating at elevated temperatures for energy
conversion and harsh-environment industries such as gas and oil. Here we report
on the temperature dependent dielectric functions of TiN thin films of varying
thicknesses in the technologically relevant visible and near-infrared
wavelength range from 330 nm to 2000 nm for temperatures up to 900 0C using
in-situ high temperature ellipsometry. Our findings show that the complex
dielectric function of TiN at elevated temperatures deviates from the optical
parameters at room temperature, indicating degradation in plasmonic properties
both in the real and imaginary parts of the dielectric constant. However, quite
strikingly, the relative changes of the optical properties of TiN are
significantly smaller compared to its noble metal counterparts. Using
simulations, we demonstrate that incorporating the temperature-induced
deviations into the numerical models leads to significant differences in the
optical responses of high temperature nanophotonic systems. These studies hold
the key for accurate modeling of high temperature TiN based optical elements
and nanophotonic systems for energy conversion, harsh-environment sensors and
heat-assisted applications.Comment: 23 pages, 9 figures and 5 table
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