Osteoporosis and sarcopenia are two conditions associated with aging and characterized by a simultaneous decline in bone and muscle mass, respectively. These conditions share common risk factors ...(genetic, endocrine, nutritional and lifestyle factors) and biological pathways that often co-exist in a syndrome known as osteosarcopenia. Among the endocrine causes, estrogens play a critical role, especially in women. Estrogens have been demonstrated to exert a positive effect on bone and muscle development and maintenance. For this reason, menopause is characterized by a loss in bone mineral density and skeletal muscle quality and quantity. To date, studies indicate a positive effect of hormonal therapy on the prevention and management of osteoporosis, to the point that estrogen is prescribed as a first-line treatment for osteoporosis by the major international authorities. While results on sarcopenia are still disputable, such that estrogens are not recommended to prevent muscle loss in postmenopausal women, increased response to anabolic stimuli with estrogen therapy suggests similar beneficial effects on muscle as seen with bone, particularly when combined with resistance exercise.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We report R 6 3000 Very Large Telescope ISAAC K-band spectroscopy of the nuclei (i.e., central 100-300 pc) of nine galaxies hosting an active galactic nucleus. For five of these we also present ...spectra of the circumnuclear region out to 1 kpc. We have measured a number of molecular hydrogen lines in the = 1-0, 2-1, and 3-2 vibrational transitions, as well as the Brg and He I recombination lines and the Na I stellar absorption feature. Although only three of the galaxies are classified as type 1 Seyfert galaxies in the literature, broad Brg (FWHM > 1000 km s super(-1)) is seen in seven of the objects. The = 1-0 emission appears thermalized at temperatures T 6 1000 K. However, the = 2-1 and = 3-2 emission show evidence of being radiatively excited by far-ultraviolet photons. The photodissociation region models that fit the data best are, as for the ultraluminous infrared galaxies in Davies et al., those for which the H sub(2) emission arises in dense clouds illuminated by intense far-ultraviolet radiation. The Na I stellar absorption line is clearly seen in six of the nuclear spectra of these AGNs, indicating the presence of a significant population of late-type stars. It is possible that these stars are a result of the same episode of star formation that gave rise to the stars heating the photodissociation regions. It seems unlikely that the AGN is the dominant source of excitation for the near-infrared H sub(2) emission: in two of the nuclear spectra H sub(2) was not detected at all, and in general we find no evidence of suppression of the 2-1 S(3) line, which may occur in X-ray-irradiated gas. Our data do not reveal any significant difference between the nuclear and circumnuclear line ratios, suggesting that the physical conditions of the dominant excitation mechanism are similar both near the AGN and in the larger scale environment around it, and that star formation is an important process even in the central 100 pc around AGNs.
In order to better characterise the usefulness of PAH emission as a tracer of star formation, we have undertaken a programme of 3 μm narrowband imaging of a sample of nearby template galaxies ...covering a wide range of metallicity, star formation activity, and nuclear activity. In the present paper we present first results of this programme: high spatial resolution images of PAH feature emission and the adjacent continuum emission from the central regions of the nearby starburst galaxies NGC 253 and NGC 1808, taken with ISAAC at the VLT-UT1. Globally, the feature emission is seen to peak on the central starburst regions of both sources. On smaller scales, however, we see no general spatial correlation or anti-correlation between the PAH feature emission and the location of sites of recent star formation, suggesting that the degree to which PAH feature emission traces starburst activity is more complicated than previously hypothesized based on results from data with lower spatial resolution. We do find spatial correlations, though, when we consider the feature-to-continuum ratio, which is low at the positions of known super star clusters in NGC 1808 as well as at the position of the IR peak in NGC 253. We take this to imply a decrease in the efficiency of PAH emission induced by the star formation, caused either by mechanical energy input into the ISM, photoionisation of the PAH molecules, or photodissociation of the PAH molecules. All three hypotheses are discussed. In addition, for the first time we present observations of PAH feature emission in the superwind of a starbursting system (NGC 253), providing strong support that winds are heavily mass-loaded and entrain substantial amounts of ambient ISM. We have also found a plausible connection between observed NaD absorption, H2, and PAHs above the plane of NGC 253. This observation has important implications for enriching galaxy halos and possibly the intergalactic medium with small dust grains.
We present the results of H- and K-band very large telescope/Spectrograph for INtegral Field Observations in the Near Infrared (VLT/SINFONI) integral field spectroscopy of the Ultraluminous Infrared ...Galaxy (ULIRG) IRAS 19 254–7245 (the Super-antennae), an interacting double galaxy system containing an embedded active galactic nuclei. Deep K-band spectroscopy reveals Paα arising in a warped disc with position angle of 330° and an inclination i= 40°–55°. The kinemetric parameters derived for H2 are similar to Paα. Two high-ionization emission lines, Si vi and Al ix, are detected and we identify as Ni ii the line observed at 1.94 μm. Diluting non-stellar continuum, which was previously detected, has decayed, and the H-band continuum emission is consistent with pure stellar emission. Based on H2 emission-line ratios, it is likely that at the central 1-kpc region H2 is excited by ultraviolet fluorescence in dense clouds while shock excitation is dominant further out. This scenario is supported by very low Paα to H2 line ratio detected outside the nuclear region and non-thermal ortho/para ratios (∼2.0–2.5) close to the nucleus.
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