Mercury emissions and stable isotopic compositions at Vulcano Island (Italy)

Sampling and analyses methods for determining the stable isotopic compositions of Hg in an active volcanic system were tested and optimized at the volcanic complex of Vulcano (Aeolian Islands, Italy). Condensed gaseous fumarole Hg(fum) T , plume gaseous elemental Hg(g) 0 and plume particulate Hg(p) II were obtained at fumaroles F0, F5, F11, and FA. The average total Hg emissions, based on HgT/SO2 in condensed fumarolic gases and plumes, range from 2.5 to 10.1 kg y−1, in agreement with published values [Ferrara, R., Mazzolai, B., Lanzillotta, E., Nucaro, E., Pirrone, N., 2000. Volcanoes as emission sources of atmospheric mercury in the Mediterranean Basin. Sci. Total Environ. 259(1–3), 115–121; Aiuppa, A., Bagnato, E., Witt, M.L.I., Mather, T.A., Parello, F., Pyle, D.M., Martin, R.S., 2007. Real-time simultaneous detection of volcanic Hg and SO2 at La Fossa Crater, Vulcano (Aeolian Islands, Sicily). Geophys. Res. Lett. 34(L21307).]. Plume Hg(p) II increases with distance from the fumarole vent, at the expense of Hg(g) 0 and indicates significant in-plume oxidation and condensation of fumarole Hg(fum) T . Relative to the NIST SRM3133 Hg standard, the stable isotopic compositions of Hg are δ202Hg(fum) T =−0.74‰±0.18 (2SD, n=4) for condensed gaseous fumarole Hg(fum) T , δ202Hg(g) 0 =−1.74‰±0.36 (2SD, n=1) for plume gaseous elemental Hg(g) 0 at the F0 fumarole, and δ202Hg(p) II =−0.11‰±0.18 (2SD, n=4) for plume particulate Hg(p) II . The enrichment of Hg(p) II in the heavy isotopes and Hg(g) 0 in the light isotopes relative to the total condensed fumarolic Hg(fum) T gas complements the speciation data and demonstrates a gas-particle fractionation occurring after the gas expulsion inambient T° atmosphere. A first order Rayleigh equilibriumcondensation isotope fractionation model yields a fractionation factor αcond-gas of 1.00135±0.00058

Comparison of in vitro static and dynamic assays to evaluate the efficacy of an antimicrobial drug combination against Staphylococcus aureus

An easily implementable strategy to reduce treatment failures in severe bacterial infections is to combine already available antibiotics. However, most in vitro combination assays are performed by exposing standard bacterial inocula to constant concentrations of antibiotics over less than 24h, which can be poorly representative of clinical situations. The aim of this study was to assess the ability of static and dynamic in vitro Time-Kill Studies (TKS) to identify the potential benefits of an antibiotic combination (here, amikacin and vancomycin) on two different inoculum sizes of two S. aureus strains. In the static TKS (sTKS), performed by exposing both strains over 24h to constant antibiotic concentrations, the activity of the two drugs combined was not significantly different the better drug used alone. However, the dynamic TKS (dTKS) performed over 5 days by exposing one strain to fluctuating concentrations representative of those observed in patients showed that, with the large inoculum, the activities of the drugs, used alone or in combination, significantly differed over time. Vancomycin did not kill bacteria, amikacin led to bacterial regrowth whereas the combination progressively decreased the bacterial load. Thus, dTKS revealed an enhanced effect of the combination on a large inoculum not observed in sTKS. The discrepancy between the sTKS and dTKS results highlights that the assessment of the efficacy of a combination for severe infections associated with a high bacterial load could be demanding. These situations probably require the implementation of dynamic assays over the entire expected treatment duration rather than the sole static assays performed with steady drug concentrations over 24h

Solar-like oscillations in the metal-poor subgiant nu Indi: II. Acoustic spectrum and mode lifetime

Convection in stars excites resonant acoustic waves which depend on the sound speed inside the star, which in turn depends on properties of the stellar interior. Therefore, asteroseismology is an unrivaled method to probe the internal structure of a star. We made a seismic study of the metal-poor subgiant star nu Indi with the goal of constraining its interior structure. Our study is based on a time series of 1201 radial velocity measurements spread over 14 nights obtained from two sites, Siding Spring Observatory in Australia and ESO La Silla Observatory in Chile. The power spectrum of the high precision velocity time series clearly presents several identifiable peaks between 200 and 500 uHz showing regularity with a large and small spacing of 25.14 +- 0.09 uHz and 2.96 +- 0.22 uHz at 330 uHz. Thirteen individual modes have been identified with amplitudes in the range 53 to 173 cm/s. The mode damping time is estimated to be about 16 days (1-sigma range between 9 and 50 days), substantially longer than in other stars like the Sun, the alpha Cen system or the giant xi Hya.Comment: 5 pages, 7 figures, A&A accepte

Skin manifestations among GATA2-deficient patients

International audienceGATA2 mutations have been identified in various diseases, such as MonoMAC syndrome, Emberger syndrome, familial myelodysplastic syndrome, acute myeloid leukaemia and dendritic cell, monocyte, B-cell and natural killer-cell deficiency. These syndromes present a wide range of clinical features, dominated by severe infections and haematological disorders such as myelodysplastic syndrome. Up to 70% of patients with GATA2 mutations have dermatological features, mainly genital or extragenital warts, panniculitis or erythema nodosum and lymphoedema. We report three patients presenting with common dermatological and haematological features leading to the diagnosis of GATA2 deficiency, but also with skin manifestations that have not been previously described gingival hypertrophy, macroglossitis and glossitis and granulomatous lupoid facial lesions. Dermatologists can encounter patients with GATA2 mutations and should recognize this disorder

Determinants of flow-mediated outward remodeling in female rodents: respective roles of age, estrogens, and timing

OBJECTIVE: Flow (shear stress)-mediated outward remodeling (FMR) of resistance arteries is a key adaptive process allowing collateral growth after arterial occlusion but declining with age. 17-beta-estradiol (E2) has a key role in this process through activation of estrogen receptor alpha (ERalpha). Thus, we investigated the impact of age and timing for estrogen efficacy on FMR. APPROACH AND RESULTS: Female rats, 3 to 18 months old, were submitted to surgery to increase blood flow locally in 1 mesenteric artery in vivo. High-flow and normal-flow arteries were collected 2 weeks later for in vitro analysis. Diameter increased by 27% in high-flow arteries compared with normal-flow arteries in 3-month-old rats. The amplitude of remodeling declined with age (12% in 18-month-old rats) in parallel with E2 blood level and E2 substitution failed restoring remodeling in 18-month-old rats. Ovariectomy of 3-, 9-, and 12-month-old rats abolished FMR, which was restored by immediate E2 replacement. Nevertheless, this effect of E2 was absent 9 months after ovariectomy. In this latter group, ERalpha and endothelial nitric oxide synthase expression were reduced by half compared with age-matched rats recently ovariectomized. FMR did not occur in ERalpha(-/-) mice, whereas it was decreased by 50% in ERalpha(+/-) mice, emphasizing the importance of gene dosage in high-flow remodeling. CONCLUSIONS: E2 deprivation, rather than age, leads to decline in FMR, which can be prevented by early exogenous E2. However, delayed E2 replacement was ineffective on FMR, underlining the importance of timing of this estrogen action

Testosterone Prevents Cutaneous Ischemia and Necrosis in Males Through Complementary Estrogenic and Androgenic Actions

OBJECTIVE: Chronic nonhealing wounds are a substantial medical concern and are associated with morbidity and mortality; thus, new treatment strategies are required. The first step toward personalized/precision medicine in this field is probably in taking sex differences into account. Impaired wound healing is augmented by ischemia, and we previously demonstrated that 17β-estradiol exerts a major preventive effect against ischemia-induced skin flap necrosis in female mice. However, the equivalent effects of testosterone in male mice have not yet been reported. We then investigated the role of steroid hormones in male mice using a skin flap ischemia model. APPROACH AND RESULTS: Castrated male mice developed skin necrosis after ischemia, whereas intact or castrated males treated with testosterone were equally protected. Testosterone can (1) activate the estrogen receptor after its aromatization into 17β-estradiol or (2) be reduced into dihydrotestosterone, a nonaromatizable androgen that activates the androgen receptor. We found that dihydrotestosterone protected castrated wild-type mice by promoting skin revascularization, probably through a direct action on resistance arteries, as evidenced using a complementary model of flow-mediated outward remodeling. 17β-estradiol treatment of castrated male mice also strongly protected them from ischemic necrosis through the activation of estrogen receptor-α by increasing skin revascularization and skin survival. Remarkably, 17β-estradiol improved skin survival with a greater efficiency than dihydrotestosterone. CONCLUSIONS: Testosterone provides males with a strong protection against cutaneous necrosis and acts through both its estrogenic and androgenic derivatives, which have complementary effects on skin survival and revascularization

PHIL photoinjector test line

LAL is now equiped with its own platform for photoinjectors tests and Research and Developement, named PHIL (PHotoInjectors at LAL). This facility has two main purposes: push the limits of the photoinjectors performances working on both the design and the associated technology and provide a low energy (MeV) short pulses (ps) electron beam for the interested users. Another very important goal of this machine will be to provide an opportunity to form accelerator physics students, working in a high technology environment. To achieve this goal a test line was realised equipped with an RF source, magnets and beam diagnostics. In this article we will desrcibe the PHIL beamline and its characteristics together with the description of the first two photoinjector realised in LAL and tested: the ALPHAX and the PHIN RF Guns

Measurement of low signal-to-noise-ratio solar p modes in spatially-resolved helioseismic data

We present an adaptation of the rotation-corrected, m-averaged spectrum technique designed to observe low signal-to-noise-ratio, low-frequency solar p modes. The frequency shift of each of the 2l+1 m spectra of a given (n,l) multiplet is chosen that maximizes the likelihood of the m-averaged spectrum. A high signal-to-noise ratio can result from combining individual low signal-to-noise-ratio, individual-m spectra, none of which would yield a strong enough peak to measure. We apply the technique to GONG and MDI data and show that it allows us to measure modes with lower frequencies than those obtained with classic peak-fitting analysis of the individual-m spectra. We measure their central frequencies, splittings, asymmetries, lifetimes, and amplitudes. The low-frequency, low- and intermediate-angular degrees rendered accessible by this new method correspond to modes that are sensitive to the deep solar interior down to the core and to the radiative interior. Moreover, the low-frequency modes have deeper upper turning points, and are thus less sensitive to the turbulence and magnetic fields of the outer layers, as well as uncertainties in the nature of the external boundary condition. As a result of their longer lifetimes (narrower linewidths) at the same signal-to-noise ratio the determination of the frequencies of lower-frequency modes is more accurate, and the resulting inversions should be more precise.Comment: 17 pages, 17 figures. Accepted for publication in ApJ on 27 January 200