Observational Constraints on the Modified Gravity Model (MOG) Proposed by Moffat: Using the Magellanic System

A simple model for the dynamics of the Magellanic Stream (MS), in the framework of modified gravity models is investigated. We assume that the galaxy is made up of baryonic matter out of context of dark matter scenario. The model we used here is named Modified Gravity (MOG) proposed by Moffat (2005). In order to examine the compatibility of the overall properties of the MS under the MOG theory, the observational radial velocity profile of the MS is compared with the numerical results using the $\chi^2$ fit method. In order to obtain the best model parameters, a maximum likelihood analysis is performed. We also compare the results of this model with the Cold Dark Matter (CDM) halo model and the other alternative gravity model that proposed by Bekenstein (2004), so called TeVeS. We show that by selecting the appropriate values for the free parameters, the MOG theory seems to be plausible to explain the dynamics of the MS as well as the CDM and the TeVeS models.Comment: 14 pages, 3 Figures, accepted in Int. J. Theor. Phy

Impact of A Cargo-Less Liposomal Formulation on Dietary Obesity-Related Metabolic Disorders in Mice.

Current therapeutic options for obesity often require pharmacological intervention with dietary restrictions. Obesity is associated with underlying inflammation due to increased tissue macrophage infiltration, and recent evidence shows that inflammation can drive obesity, creating a feed forward mechanism. Therefore, targeting obesity-induced macrophage infiltration may be an effective way of treating obesity. Here, we developed cargo-less liposomes (UTS-001) using 1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC (synthetic phosphatidylcholine) as a single-agent to manage weight gain and related glucose disorders due to high fat diet (HFD) consumption in mice. UTS-001 displayed potent immunomodulatory properties, including reducing resident macrophage number in both fat and liver, downregulating liver markers involved in gluconeogenesis, and increasing marker involved in thermogenesis. As a result, UTS-001 significantly enhanced systemic glucose tolerance in vivo and insulin-stimulated cellular glucose uptake in vitro, as well as reducing fat accumulation upon ad libitum HFD consumption in mice. UTS-001 targets tissue residence macrophages to suppress tissue inflammation during HFD-induced obesity, resulting in improved weight control and glucose metabolism. Thus, UTS-001 represents a promising therapeutic strategy for body weight management and glycaemic control

The velocity dispersion and mass function of the outer halo globular cluster Palomar 4

We obtained precise line-of-sight radial velocities of 23 member stars of the remote halo globular cluster Palomar 4 (Pal 4) using the High Resolution Echelle Spectrograph (HIRES) at the Keck I telescope. We also measured the mass function of the cluster down to a limiting magnitude of V~28 mag using archival HST/WFPC2 imaging. We derived the cluster's surface brightness profile based on the WFPC2 data and on broad-band imaging with the Low-Resolution Imaging Spectrometer (LRIS) at the Keck II telescope. We find a mean cluster velocity of 72.55+/-0.22 km/s and a velocity dispersion of 0.87+/-0.18 km/s. The global mass function of the cluster, in the mass range 0.55<=M<=0.85 M_solar, is shallower than a Kroupa mass function and the cluster is significantly depleted in low-mass stars in its center compared to its outskirts. Since the relaxation time of Pal 4 is of the order of a Hubble time, this points to primordial mass segregation in this cluster. Extrapolating the measured mass function towards lower-mass stars and including the contribution of compact remnants, we derive a total cluster mass of 29800 M_solar. For this mass, the measured velocity dispersion is consistent with the expectations of Newtonian dynamics and below the prediction of Modified Newtonian Dynamics (MOND). Pal 4 adds to the growing body of evidence that the dynamics of star clusters in the outer Galactic halo can hardly be explained by MOND.Comment: 17 pages, accepted for publication in MNRAS; Fig. 8 surface brightness/density data at github.com/matthiasjfrank/pal4_surface_brightnes

Testing Fundamental Physics with Distant Star Clusters: Analysis of Observational Data on Palomar 14

We use the distant outer halo globular cluster Palomar 14 as a test case for classical vs. modified Newtonian dynamics (MOND). Previous theoretical calculations have shown that the line-of-sight velocity dispersion predicted by these theories can differ by up to a factor of three for such sparse, remote clusters like Pal 14. We determine the line-of-sight velocity dispersion of Palomar 14 by measuring radial velocities of 17 red giant cluster members obtained using the Very Large Telescope (VLT) and Keck telescope. The systemic velocity of Palomar 14 is (72.28+-0.12)km/s. The derived velocity dispersion of (0.38+-0.12)km/s of the 16 definite member stars is in agreement with the theoretical prediction for the classical Newtonian case according to Baumgardt et al. (2005). In order to exclude the possibility that a peculiar mass function might have influenced our measurements, we derived the cluster's main sequence mass function down to 0.53Msolar using archival images obtained with the Hubble Space Telescope. We found a mass function slope of 1.27+-0.44, which is, compared to the canonical mass function, a significantly shallower slope. The derived lower limit on the cluster's mass is higher than the theoretically predicted mass in case of MOND. Our data are consistent with a central density of 0.1 Msolar pc^-3. We need no dark matter in Palomar 14. If the cluster is on a circular orbit, our spectroscopic and photometric results argue against MOND, unless this cluster experienced significant mass loss.Comment: 17 pages, 11 figures. Accepted for publication in A

Epicardial adipose tissue in patients with heart failure

<p>Abstract</p> <p>Purpose</p> <p>The aim of this study was to evaluate the extent of epicardial adipose tissue (EAT) and its relationship with left ventricular (LV) parameters assessed by cardiovascular magnetic resonance (CMR) in patients with congestive heart failure (CHF) and healthy controls.</p> <p>Background</p> <p>EAT is the true visceral fat deposited around the heart which generates various bioactive molecules. Previous studies found that EAT is related to left ventricular mass (LVM) in healthy subjects. Further studies showed a constant EAT to myocardial mass ratio in normal, ischemic and hypertrophied hearts.</p> <p>Methods</p> <p>CMR was performed in 66 patients with CHF due to ischemic cardiomyopathy (ICM), or dilated cardiomyopathy (DCM) and 32 healthy controls. Ventricular volumes, dimensions and LV function were assessed. The amount of EAT was determined volumetrically and expressed as mass indexed to body surface area. Additionally, the EAT/LVM and the EAT/left ventricular remodelling index (LVRI) ratios were calculated.</p> <p>Results</p> <p>Patients with CHF had less indexed EAT mass than controls (22 ± 5 g/m²versus 34 ± 4 g/m², p < 0.0001). In the subgroup analysis there were no significant differences in indexed EAT mass between patients with ICM and DCM (21 ± 4 g/m²versus 23 ± 6 g/m², p = 0.14). Linear regression analysis showed that with increasing LV end-diastolic diameter (LV-EDD) (r = 0.42, p = 0.0004) and LV end-diastolic mass (LV-EDM) (r = 0.59, p < 0.0001), there was a significantly increased amount of EAT in patients with CHF. However, the ratio of EAT mass/LV-EDM was significantly reduced in patients with CHF compared to healthy controls (0.54 ± 0.1 versus 0.21 ± 0.1, p < 0.0001). In CHF patients higher indexed EAT/LVRI-ratios in CHF patients correlated best with a reduced LV-EF (r = 0.49, p < 0.0001).</p> <p>Conclusion</p> <p>Patients with CHF revealed significantly reduced amounts of EAT. An increase in LVM is significantly related to an increase in EAT in both patients with CHF and controls. However, different from previous reports the EAT/LVEDM-ratio in patients with CHF was significantly reduced compared to healthy controls. Furthermore, the LV function correlated best with the indexed EAT/LVRI ratio in CHF patients. Metabolic abnormalities and/or anatomic alterations due to disturbed cardiac function and geometry seem to play a key role and are a possible explanation for these findings.</p

The velocity dispersion and mass-to-light ratio of the remote halo globular cluster NGC 2419

Precise radial velocity measurements from HIRES on the Keck I telescope are presented for 40 stars in the outer halo globular cluster NGC 2419. These data are used to probe the cluster's stellar mass function and search for the presence of dark matter in this cluster. NGC 2419 is one of the best Galactic globular clusters for such a study due to its long relaxation time (T_{r0} ~ 10^{10} yr) and large Galactocentric distance (R_{GC} ~ 90 kpc) -- properties that make significant evolutionary changes in the low-mass end of the cluster mass function unlikely. We find a mean cluster velocity of =-20.3 +- 0.7 km/sec and an internal velocity dispersion of \sigma = 4.14 +- 0.48 km/sec, leading to a total mass of (9.0 +- 2.2) * 10^5 Msun and a global mass-to-light ratio of M/L_V = 2.05 +- 0.50 in solar units. This mass-to-light ratio is in good agreement with what one would expect for a pure stellar system following a standard mass function at the metallicity of NGC 2419. In addition, the mass-to-light ratio does not appear to rise towards the outer parts of the cluster. Our measurements therefore rule out the presence of a dark matter halo with mass larger than ~10^7 Msun inside the central 500 pc, which is lower than what is found for the central dark matter densities of dSph galaxies. We also discuss the relevance of our measurements for alternative gravitational theories such as MOND, and for possible formation scenarios of ultra-compact dwarf galaxies.Comment: 11 pages, 7 figures, MNRAS in pres

Takotsubo cardiomyopathy after a dancing session: a case report

<p>Abstract</p> <p>Introduction</p> <p>Stress-induced (Takotsubo) cardiomyopathy is a rare form of cardiomyopathy which presents in a manner similar to that of acute coronary syndrome. This sometimes leads to unnecessary thrombolysis therapy. The pathogenesis of this disease is still poorly understood. We believe that reporting all cases of Takotsubo cardiomyopathy will contribute to a better understanding of this disease. Here, we report a patient who, in the absence of any recent stressful events in her life, developed the disease after a session of dancing.</p> <p>Case presentation</p> <p>A 69-year-old Caucasian woman presented with features suggestive of acute coronary syndrome shortly after a session of dancing. Echocardiography and a coronary angiogram showed typical features of Takotsubo cardiomyopathy and our patient was treated accordingly. Eight weeks later, her condition resolved completely and the results of echocardiography were totally normal.</p> <p>Conclusions</p> <p>Takotsubo cardiomyopathy, though transient, is a rare and serious condition. Although it is commonly precipitated by stressful life events, these are not necessarily present. Our patient was enjoying one of her hobbies (that is, dancing) when she developed the disease. This case has particular interest in medicine, especially for the specialties of cardiology and emergency medicine. We hope that it will add more information to the literature about this rare condition.</p

Acute ECG ST-segment elevation mimicking myocardial infarction in a patient with pulmonary embolism

Pulmonary embolism is a common cardiovascular emergency, but it is still often misdiagnosed due to its unspecific clinical symptoms. Elevated troponin concentrations are associated with greater morbidity and mortality in patients with pulmonary embolism. Right ventricular ischemia due to increased right ventricular afterload is believed to be underlying mechanism of elevated troponin values in acute pulmonary embolism, but a paradoxical coronary artery embolism through opened intra-artrial communication is another possible explanation as shown in our case report