7 research outputs found
Polycyclic Aromatic Hydrocarbon Emission in Spitzer/IRS Maps. I. Catalog and Simple Diagnostics
Laboratory astrophysics and astrochemistr
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Obesity, diabetes and longevity in the Gulf: is there a Gulf Metabolic Syndrome?
The Gulf is experiencing a pandemic of lifestyle-induced obesity and type 2 diabetes mellitus (T2DM), with rates exceeding 50 and 30%, respectively. It is likely that T2DM represents the tip of a very large metabolic syndrome iceberg, which precedes T2DM by many years and is associated with abnormal/ectopic fat distribution, pathological systemic oxidative stress and inflammation. However, the definitions are still evolving with the role of different fat depots being critical. Hormetic stimuli, which include exercise, calorie restriction, temperature extremes, dehydration and even some dietary components (such as plant polyphenols), may well modulate fat deposition. All induce physiological levels of oxidative stress, which results in mitochondrial biogenesis and increased anti-oxidant capacity, improving metabolic flexibility and the ability to deal with lipids. We propose that the Gulf Metabolic Syndrome results from an unusually rapid loss of hormetic stimuli within an epigenetically important time frame of 2-3 generations. Epigenetics indicates that thriftiness can be programmed by the environment and passed down through several generations. Thus this loss of hormesis can result in continuation of metabolic inflexibility, with mothers exposing the foetus to a milieu that perpetuates a stressed epigenotype. As the metabolic syndrome increases oxidative stress and reduces life expectancy, a better descriptor may therefore be the Lifestyle-Induced Metabolic Inflexibility and accelerated AGEing syndrome – LIMIT-AGE. As life expectancy in the Gulf begins to fall, with perhaps a third of this life being unhealthy – including premature loss of sexual function, it is vital to detect evidence of this condition as early in life as possible. One effective way to do this is by detecting evidence of metabolic inflexibility by studying body fat content and distribution by magnetic resonance (MR). The Gulf Metabolic Syndrome thus represents an accelerated form of the metabolic syndrome induced by the unprecedented rapidity of lifestyle change in the region, the stress of which is being passed from generation to generation and may be accumulative. The fundamental cause is probably due to a rapid increase in countrywide wealth. This has benefited most socioeconomic groups, resulting in the development of an obesogenic environment as the result of the rapid adoption of Western labour saving and stress relieving devices (e.g. cars and air conditioning), as well as the associated high calorie diet
POLYCYCLIC AROMATIC HYDROCARBON EMISSION IN SPITZER
We present a sample of resolved galactic HII regions and photodissociation
regions (PDRs) observed with the Spitzer infrared spectrograph (IRS) in
spectral mapping mode between the wavelengths of 5--15 m. For each object
we have spectral maps at a spatial resolution of 4" in which we have
measured all of the mid-infrared emission and absorption features. These
include the PAH emission bands, primarily at 6.2, 7.7, 8.6, 11.2 and 12.7
m, as well as the spectral emission lines of neon and sulfur and the
absorption band caused by silicate dust at around 9.8 m. In this work we
describe the data in detail, including the data reduction and measurement
strategies, and subsequently present the PAH emission band intensity
correlations for each of the objects and the sample as a whole. We find that
there are distinct differences between the sources in the sample, with two main
groups, the first comprising the HII regions and the second the reflection
nebulae (RNe). Three sources, the reflection nebula NGC~7023, the Horsehead
nebula PDR (an interface between the HII region IC~434 and the Orion B
molecular cloud) and M 17, resist this categorization, with the Horsehead PDR
points mimicking the RNe and the NGC~7023 fluxes displaying unique bifurcated
appearance in our correlation plots. These discrepancies seem to be due to the
very low radiation field experienced by the Horsehead PDR and the very clean
separation between the PDR environment and a diffuse environment in the
NGC~7023 observations.Comment: 17 pages, 9 figures. ApJ accepte