Using globular clusters to test gravity in the weak acceleration regime: NGC 7099

A test of Newton's law of gravity in the low acceleration regime using globular clusters is presented. New results for the core collapsed globular cluster NGC 7099 are given. The run of the gravitational potential as a function of distance is probed studying the velocity dispersion profile of the cluster, as derived from a set of 125 radial velocities with accuracy better than 1 km/s. The velocity dispersion profile is traced up to ~18 pc from the cluster center. The dispersion is found to be maximal at the center, then decrease until 10+-2 pc from the center, well inside the cluster tidal radius of 42 pc. After that the dispersion remains constant with average value 2.2+-0.3 km/s. Assuming for NGC 7099 a total V mag of M(V)=-7.43 mags and mass-to-light ratio M/L=1, the acceleration at 10 pc from the center is 1.1e-8 cm/s/s. Thus, the flattening of the velocity dispersion profile occurs for a value of the internal acceleration of gravity fully consistent with a_0=1.2e-8 cm/s/s observed in galaxies. This new result for NGC 7099 brings to 4 the clusters with velocity dispersion profile probing acceleration below a_0. All four have been found to have a flat dispersion profile at large radii where the acceleration is below a_0, mimicking qualitatively and quantitatively elliptical galaxies. Whether this indicates a failure of Newtonian dynamics in the low acceleration limit or some more conventional dynamical effect (e.g., tidal heating) is still unclear. However, the similarities emerging between very different globular clusters, as well as between globular clusters and elliptical galaxies seem to favor the first of these two possibilities.Comment: Accepted for publication in A&A Letters. Four pages in tota

Using globular clusters to test gravity in the weak acceleration regime

We report on the results from an ongoing program aimed at testing Newton's law of gravity in the low acceleration regime using globular clusters. It is shown that all clusters studied so far do behave like galaxies, that is, their velocity dispersion profile flattens out at large radii where the acceleration of gravity goes below 1e-8 cm/s/s, instead of following the expected Keplerian fall off. In galaxies this behavior is ascribed to the existence of a dark matter halo. Globular clusters, however, do not contain dark matter, hence this result might indicate that our present understanding of gravity in the weak regime of accelerations is incomplete and somehow incorrect.Comment: As published on the European Southern Observatory "the Messenger", Num. 128, June 2007. Seven pages, 4 figures, 2 table

Abundance analysis of a sample of evolved stars in the outskirts of Omega Centauri

The globular cluster $\omega$ Centauri (NGC 5139) is a puzzling stellar system harboring several distinct stellar populations whose origin still represents a unique astrophysical challenge. Current scenarios range from primordial chemical inhomogeneities in the mother cloud to merging of different sub-units and/or subsequent generations of enriched stars - with a variety of different pollution sources- within the same potential well. In this paper we study the chemical abundance pattern in the outskirts of Omega Centauri, half-way to the tidal radius (covering the range of 20-30 arcmin from the cluster center), and compare it with chemical trends in the inner cluster regions, in an attempt to explore whether the same population mix and chemical compositions trends routinely found in the more central regions is also present in the cluster periphery.We extract abundances of many elements from FLAMES/UVES spectra of 48 RGB stars using the equivalent width method and then analyze the metallicity distribution function and abundance ratios of the observed stars. We find, within the uncertainties of small number statistics and slightly different evolutionary phases, that the population mix in the outer regions cannot be distinguished from the more central regions, although it is clear that more data are necessary to obtain a firmer description of the situation. From the abundance analysis, we did not find obvious radial gradients in any of the measured elements.Comment: 22 pages, 8 eps figures, in press in New Astronom

The blocking of angiotensin II type 1 receptor and RhoA/Rho kinase activity in hypertensive patients: Effect of olmesartan medoxomil and implication with cardiovascular-renal remodeling

Hypothesis/Introduction: The pathophysiological role of oxidative stress (OxSt) in hypertension and target organ damage is recognized. Angiotensin II (Ang II) induces OxSt via NAD(P)H oxidase activation and production of proinflammatory cytokines/growth factors leading to cardiovascular-renal remodeling. Ang II stimulates the RhoA/Rho kinase (ROCK) pathway, which is deeply involved in the development of cardiovascular-renal remodeling via OxSt induction. Olmesartan, an Ang II type 1 receptor blocker, possesses antioxidant and activating nitric oxide system-related effects, which we have shown in terms of p22 phox reduction, heme oxygenase-1 and calcitonin gene-related peptide increase. This study evaluates in 15 untreated hypertensive patients the effect of olmesartan treatment on p63RhoGEF, key in Ang II-induced ROCK activation, and MYPT-1 phosphorylation, a marker of ROCK activity. Materials and methods: The p63RhoGEF protein level and MYPT-1 phosphorylation (Western blot) were evaluated at baseline, and after three and six months of olmesartan treatment. Results: Olmesartan normalized systolic and diastolic BP ( p < 0.001), reduced p63RhoGEF level: 1.3±0.25 d.u. (baseline) vs 1.0±0.29 (three months), p < 0.0001 vs 1.0±0.22, (six months), p < 0.0001 and MYPT-1 phosphorylation: 1.2 ±0.14 (baseline) vs 0.9±0.19 (three months), p = 0.008, vs 0.8±0.16 (six months), p = 0.001. Conclusions: These data added to our previous results further provide a mechanistic rationale for olmesartan's antioxidant/anti-inflammatory potential translation, in the long term, toward anti-atherosclerotic/anti-remodeling effects reported by clinical trials

Vortex Entanglement and Broken Symmetry

Based on the London approximation, we investigate numerically the stability of the elementary configurations of entanglement, the twisted-pair and the twisted-triplet, in the vortex-lattice and -liquid phases. We find that, except for the dilute limit, the twisted-pair is unstable and hence irrelevant in the discussion of entanglement. In the lattice phase the twisted-triplet constitutes a metastable, confined configuration of high energy. Loss of lattice symmetry upon melting leads to deconfinement and the twisted-triplet turns into a low-energy helical configuration.Comment: 4 pages, RevTex, 2 figures on reques

Single-Cell Transcriptomic Profiling of Pluripotent Stem Cell-Derived SCGB3A2+ Airway Epithelium.

Lung epithelial lineages have been difficult to maintain in pure form in&nbsp;vitro, and lineage-specific reporters have proven invaluable for monitoring their emergence from cultured pluripotent stem cells (PSCs). However, reporter constructs for tracking proximal airway lineages generated from PSCs have not been previously available, limiting the characterization of these cells. Here, we engineer mouse and human PSC lines carrying airway secretory lineage reporters that facilitate the tracking, purification, and profiling of this lung subtype. Through bulk and single-cell-based global transcriptomic profiling, we find PSC-derived airway secretory cells are susceptible to phenotypic plasticity exemplified by the tendency to co-express both a proximal airway secretory program as well as an alveolar type 2 cell program, which can be minimized by inhibiting endogenous Wnt signaling. Our results provide global profiles of engineered lung cell fates, a guide for improving their directed differentiation, and a human model of the developing airway

The Relevance of Assessing Subjective Experiences of Skin Toxicity During Adjuvant Radiotherapy for Breast Cancer

Purpose: Radiodermatitis is likely to be an inevitable side effect of radiotherapy (RT) but experiencing pain relief during RT might contribute making treatment more acceptable and less impairing. The current study aimed to assess the subjective perceptions and experiences of skin toxicity in a sample of women undergoing adjuvant RT for breast cancer. Methods: Eighty patients were randomly assigned to one out of two groups: treatment (i.e., a newly developed topical product) and control (i.e., standard-of-care). Patients underwent adjuvant RT for 3 weeks. Clinical assessment of radiodermatitis and self-reported levels of pain, relief, and perceptions of treatment response were collected at the initiation of RT (T1), during RT (T2 and T3), and 2 weeks after treatment completion (T4). To assess changes in skin-related QoL, a subgroup of patients completed the Padua Skin-Related QoL questionnaire at T0 (before the initiation of RT) and at T4. Results: A comparable timing of onset and severity of radiodermatitis during treatment was observed in both groups. The treatment group reported lower levels of pain and higher levels of relief compared to the control group when skin toxicity was at its highest levels (T2 and T3). Independent of the group, levels of perceived improvements in clinical status increased over time, whereas skin-related QoL worsened from T0 to T4. Conclusion: Current findings outline the relevance of integrating clinical evaluations of radiodermatitis with patients\u2019 subjective experiences of skin toxicity in interventional studies. Moreover, they provide preliminary evidence about the soothing effect of a newly developed topical product, thus supporting its usefulness of as a supportive care

Efficient generation and transcriptomic profiling of human iPSC-derived pulmonary neuroendocrine cells

Expansion of pulmonary neuroendocrine cells (PNECs) is a pathological feature of many human lung diseases. Human PNECs are inherently difficult to study due to their rarity (\u3c1% of total lung cells) and a lack of established protocols for their isolation. We used induced pluripotent stem cells (iPSCs) to generate induced PNECs (iPNECs), which express core PNEC markers, including ROBO receptors, and secrete major neuropeptides, recapitulating known functions of primary PNECs. Furthermore, we demonstrate that differentiation efficiency is increased in the presence of an air-liquid interface and inhibition of Notch signaling. Single-cell RNA sequencing (scRNA-seq) revealed a PNEC-associated gene expression profile that is concordant between iPNECs and human fetal PNECs. In addition, pseudotime analysis of scRNA-seq results suggests a basal cell origin of human iPNECs. In conclusion, our model has the potential to provide an unlimited source of human iPNECs to explore PNEC pathophysiology associated with several lung diseases

Old open clusters and the Galactic metallicity gradient: Berkeley 20, Berkeley 66, and Tombaugh 2

To study the crucial range of Galactocentric distances between 12 and 16 kpc, where little information is available, we have obtained VI CCD imaging of Berkeley 20 and BVI CCD imaging of Berkeley 66 and Tombaugh 2, three distant, old open clusters. Using the synthetic colour magnitude diagram (CMD) technique with three types of evolutionary tracks of different metallicities, we have determined age, distance, reddening and indicative metallicity of these systems. The CMD of Be 20 is best reproduced by stellar models with a metallicity about half of solar (Z=0.008 or 0.01), in perfect agreement with high resolution spectroscopic estimates. Its age is between 5 and 6 Gyr from stellar models with overshooting and between 4.3 and 4.5 Gyr from models without it. The distance modulus from the best fitting models is always (m-M)0=14.7 (corresponding to a Galactocentric radius of about 16 kpc), and the reddening E(B-V) ranges between 0.13 and 0.16. A slightly lower metallicity (Z ~ 0.006) appears to be more appropriate for Be 66. This cluster is younger, (age of 3 Gyr), and closer, (m-M)0=13.3 (i.e., at 12 kpc from the Galactic centre), than Be 20, and suffers from high extinction, 1.2 < E(B-V) < 1.3, variable at the 2-3 per cent level. Finally, the results for To 2 indicate that it is an intermediate age cluster, with an age of about 1.4 Gyr or 1.6-1.8 Gyr for models without and with overshooting, respectively. The metallicity is about half of solar (Z=0.006 to 0.01), in agreement with spectroscopic determinations. The distance modulus is (m-M)0=14.5, implying a distance of about 14 kpc from the Galactic centre; the reddening E(B-V) is 0.31-0.4, depending on the model and metallicity, with a preferred value around 0.34.Comment: 19 pages, 19 figures, 8 tables Accepted 2010 November 5. Received 2010 Novembe