128 research outputs found
Pioglitazone versus Rosiglitazone: Effects on Lipids, Lipoproteins, and Apolipoproteins in Head-to-Head Randomized Clinical Studies
Peroxisome proliferator-activated receptors (PPARs) play an important role in regulating both glucose and lipid metabolism. Agonists for both PPARγ and PPARγ have been used to treat dyslipidemia and hyperglycemia, respectively. In addition to affecting glucose metabolism, PPARγ agonists also regulate lipid metabolism. In this review, we will focus on the randomized clinical trials that directly compared the lipid effects of the thiazolidinedione class of PPARγ agonists, pioglitazone and rosiglitazone, head-to-head either as monotherapy or in combination with other lipid-altering or glucose-lowering agent
Outward Migration of Terrestrial Embryos in Binary Systems
We consider the formation and migration of protoplanetary embryos in disks
around the stars in tight binary systems (separations ~ 20 AU. In such systems,
the initial stages of runaway embryo formation are expected to only take place
within some critical disk radius a_{crit}, due to the perturbing effect of the
binary companions (Thebault et al. 2009). We perform n-body simulations of the
evolution of such a population of inner-disk embryos surrounded by an
outer-disk of smaller planetesimals. Taking Alpha Centauri-B as our fiducial
reference example in which a_{crit} ~ 0.7 AU, and using a Minimum Mass Nebular
Model with , we find that within 10^6 yrs (10^7 yrs),
systems will on average contain embryos which have migrated out to 0.9 AU (1.2
AU), with the average outer-most body having a mass of 0.2 M_{earth} 0.4
M_{earth}. Changes to increase the surface density of solids or to use a
flatter profile both produce increased embryo migration and growth. At a given
time, the relative change in semi-major axis of the outer-most embryo in these
simulations is found to be essentially independent of a_{crit}, and we note
that little further embryo migration takes place beyond 10^7 years. We conclude
that the suppression of runaway growth outside a_{crit} does not mean that the
habitable zones in such tight binary systems will be devoid of detectable,
terrestrial mass planets, even if a_{crit} lies significantly interior to the
inner edge of the habitable zone.Comment: Accepted for publication in MNRA
Absolute properties of the low-mass eclipsing binary CM Draconis
Spectroscopic and eclipsing binary systems offer the best means for
determining accurate physical properties of stars, including their masses and
radii. The data available for low-mass stars have yielded firm evidence that
stellar structure models predict smaller radii and higher effective
temperatures than observed, but the number of systems with detailed analyses is
still small. In this paper we present a complete reanalysis of one of such
eclipsing systems, CM Dra, composed of two dM4.5 stars. New and existing light
curves as well as a radial velocity curve are modeled to measure the physical
properties of both components. The masses and radii determined for the
components of CM Dra are M1=0.2310+/-0.0009 Msun, M2=0.2141+/-0.0010 Msun,
R1=0.2534+/-0.0019 Rsun, and R2=0.2396+/-0.0015 Rsun. With relative
uncertainties well below the 1% level, these values constitute the most
accurate properties to date for fully convective stars. This makes CM Dra a
valuable benchmark for testing theoretical models. In comparing our
measurements with theory, we confirm the discrepancies reported previously for
other low-mass eclipsing binaries. These discrepancies seem likely to be due to
the effects of magnetic activity. We find that the orbit of this system is
slightly eccentric, and we have made use of eclipse timings spanning three
decades to infer the apsidal motion and other related properties.Comment: 19 pages, 9 figures. Accepted for publication in Ap
Neurodevelopmental effects of chronic exposure to elevated levels of pro-inflammatory cytokines in a developing visual system
<p>Abstract</p> <p>Background</p> <p>Imbalances in the regulation of pro-inflammatory cytokines have been increasingly correlated with a number of severe and prevalent neurodevelopmental disorders, including autism spectrum disorder, schizophrenia and Down syndrome. Although several studies have shown that cytokines have potent effects on neural function, their role in neural development is still poorly understood. In this study, we investigated the link between abnormal cytokine levels and neural development using the <it>Xenopus laevis </it>tadpole visual system, a model frequently used to examine the anatomical and functional development of neural circuits.</p> <p>Results</p> <p>Using a test for a visually guided behavior that requires normal visual system development, we examined the long-term effects of prolonged developmental exposure to three pro-inflammatory cytokines with known neural functions: interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α. We found that all cytokines affected the development of normal visually guided behavior. Neuroanatomical imaging of the visual projection showed that none of the cytokines caused any gross abnormalities in the anatomical organization of this projection, suggesting that they may be acting at the level of neuronal microcircuits. We further tested the effects of TNF-α on the electrophysiological properties of the retinotectal circuit and found that long-term developmental exposure to TNF-α resulted in enhanced spontaneous excitatory synaptic transmission in tectal neurons, increased AMPA/NMDA ratios of retinotectal synapses, and a decrease in the number of immature synapses containing only NMDA receptors, consistent with premature maturation and stabilization of these synapses. Local interconnectivity within the tectum also appeared to remain widespread, as shown by increased recurrent polysynaptic activity, and was similar to what is seen in more immature, less refined tectal circuits. TNF-α treatment also enhanced the overall growth of tectal cell dendrites. Finally, we found that TNF-α-reared tadpoles had increased susceptibility to pentylenetetrazol-induced seizures.</p> <p>Conclusions</p> <p>Taken together our data are consistent with a model in which TNF-α causes premature stabilization of developing synapses within the tectum, therefore preventing normal refinement and synapse elimination that occurs during development, leading to increased local connectivity and epilepsy. This experimental model also provides an integrative approach to understanding the effects of cytokines on the development of neural circuits and may provide novel insights into the etiology underlying some neurodevelopmental disorders.</p
A New Spectroscopic and Photometric Analysis of the Transiting Planet Systems TrES-3 and TrES-4
We report new spectroscopic and photometric observations of the parent stars of the recently discovered transiting planets TrES-3 and TrES-4. A detailed abundance analysis based on high-resolution spectra yields [Fe/H] = –0.19 ± 0.08, T_(eff) = 5650 ± 75 K, and log g = 4.4 ± 0.1 for TrES-3, and [Fe/H] = +0.14 ± 0.09, T_(eff) = 6200 ± 75 K, and log g = 4.0 ± 0.1 for TrES-4. The accuracy of the effective temperatures is supported by a number of independent consistency checks. The spectroscopic orbital solution for TrES-3 is improved with our new radial velocity measurements of that system, as are the light-curve parameters for both systems based on newly acquired photometry for TrES-3 and a reanalysis of existing photometry for TrES-4. We have redetermined the stellar parameters taking advantage of the strong constraint provided by the light curves in the form of the normalized separation a/R_* (related to the stellar density) in conjunction with our new temperatures and metallicities. The masses and radii we derive are M_* = 0.928^(+0.028)_(–0.048) M_⊙, R_* = 0.829^(+0.015)_(–0.022) R_⊙, and M_* = 1.404^(+0.066)_(–0.134) M_⊙, R_* = 1.846^(+0.096)_(–0.087) R_⊙ for TrES-3 and TrES-4, respectively. With these revised stellar parameters, we obtain improved values for the planetary masses and radii. We find M_p = 1.910^(+0.075)_(–0.080) M_(Jup), R_p = 1.336^(+0.031)_(–0.036) R_(Jup) for TrES-3, and M_p = 0.925 ± 0.082 M_(Jup), R_p = 1.783^(+0.093)_(–0.086) R_(Jup) for TrES-4. We confirm TrES-4 as the planet with the largest radius among the currently known transiting hot Jupiters
TrES-3: A Nearby, Massive, Transiting Hot Jupiter in a 31-Hour Orbit
We describe the discovery of a massive transiting hot Jupiter with a very
short orbital period (1.30619 d), which we name TrES-3. From spectroscopy of
the host star GSC 03089-00929, we measure T_eff = 5720 +- 150 K, logg=4.6 +-
0.3, and vsini < 2 km/s, and derive a stellar mass of 0.90 +- 0.15 M_sun. We
estimate a planetary mass of 1.92 +- 0.23 M_Jup, based on the sinusoidal
variation of our high-precision radial velocity measurements. This variation
has a period and phase consistent with our transit photometry. Our spectra show
no evidence of line bisector variations that would indicate a blended eclipsing
binary star. From detailed modeling of our B and z photometry of the 2.5%-deep
transits, we determine a stellar radius 0.802 +- 0.046 R_sun and a planetary
radius 1.295 +- 0.081 R_Jup. TrES-3 has one of the shortest orbital periods of
the known transiting exoplanets, facilitating studies of orbital decay and mass
loss due to evaporation, and making it an excellent target for future studies
of infrared emission and reflected starlight.Comment: v1. 14 pages, 2 figures, 3 tables. Submitted to ApJL 27 April 2007.
Accepted for publication in ApJL 14 May 200
Self-perceived weather sensitivity and joint pain in older people with osteoarthritis in six European countries: Results from the European Project on OSteoArthritis (EPOSA)
People with osteoarthritis (OA) frequently report that their joint pain is influenced by weather conditions. This study aimed to examine whether there are differences in perceived joint pain between older people with OA who reported to be weather-sensitive versus those who did not in six European countries with different climates and to identify characteristics of older persons with OA that are most predictive of perceived weather sensitivity.
Methods
Baseline data from the European Project on OSteoArthritis (EPOSA) were used. ACR classification criteria were used to determine OA. Participants with OA were asked about their perception of weather as influencing their pain. Using a two-week follow-up pain calendar, average self-reported joint pain was assessed (range: 0 (no pain)-10 (greatest pain intensity)). Linear regression analyses, logistic regression analyses and an independent t-test were used. Analyses were adjusted for several confounders.
Results
The majority of participants with OA (67.2%) perceived the weather as affecting their pain. Weather-sensitive participants reported more pain than non-weather-sensitive participants (M = 4.1, SD = 2.4 versus M = 3.1, SD = 2.4; p < 0.001). After adjusting for several confounding factors, the association between self-perceived weather sensitivity and joint pain remained present (B = 0.37, p = 0.03). Logistic regression analyses revealed that women and more anxious people were more likely to report weather sensitivity. Older people with OA from Southern Europe were more likely to indicate themselves as weather-sensitive persons than those from Northern Europe.
Conclusions
Weather (in)stability may have a greater impact on joint structures and pain perception in people from Southern Europe. The results emphasize the importance of considering weather sensitivity in daily life of older people with OA and may help to identify weather-sensitive older people with OA.The Indicators for Monitoring COPD and Asthma - Activity and Function in
the Elderly in Ulm study (IMCA - ActiFE) is supported by the European Union
(No.: 2005121) and the Ministry of Science, Baden-Württemberg. The Italian
cohort study is part of the National Research Council Project on Aging (PNR).
The Longitudinal Aging Study Amsterdam (LASA) is financially supported by
the Dutch Ministry of Health, Welfare and Sports. The Peñagrande study was
partially supported by the National Fund for Health Research (Fondo de
Investigaciones en Salud) of Spain (project numbers FIS PI 05/1898; FIS RETICEF
RD06/0013/1013 and FIS PS09/02143). The Swedish Twin Registry is supported
in part by the Swedish Ministry of Higher Education. The Hertfordshire Cohort
Study was supported by the Medical Research Council, UK
Health and prolonging working lives: an advisory report of the Health Council of The Netherlands
Objective This paper summarizes the main findings and recommendations of an advisory report on health and
prolonging working life, which was requested by the Dutch Minister of Social Affairs and Employment.
Methods The advisory report was compiled by a multidisciplinary committee of ten scientists appointed by the
Health Council of The Netherlands. The committee's aims were to (i) describe the health of the ageing population, (ii) describe how prolonging working life influences health, (iii) describe determinants, besides health,
for prolonging working lives, and (iv) review the literature on interventions aimed at retaining or improving
employability of older workers.
Results The report was presented to the Minister on 26 June 2018. As the likelihood of health problems increases
with age, prolonging working life may be difficult. In general, life expectancy increases and gains in life years and
health seem mainly attributable to people aged >75 years. Work is good for mental health. However, it may be
beneficial for mental health to stop working around the retirement age. Besides health, financial factors, lifestyle,
motivation to work, and working conditions play a role in prolonging working life. A systematic review of the
evidence indicated that interventions such as worksite health promotion or career development workshops can
support older workers in this matter.
Conclusions The Health Council advised the Dutch Government to focus on worksite health promotion and
career development interventions as well as the improvement of their implementation. This requires a tailored
approach as there is a large diversity in health among older workers and particularly between low- and higheducated people. With this in mind, it was further recommended to explore whether flexible pension schemes
might better suit this diversit
- …