A new all-metal induction furnace for noble gas extraction

A new all-metal induction furnace for extraction of all noble gases from pyroxenes, olivines, quartz or barites has been developed at CRPG. It differs in design from other induction furnaces in that the totality of the vacuum vessel is metallic and the induction coil, normally located outside the furnace, has been placed inside the vacuum vessel, with a special radio frequency power feedthrough welded onto a flange. The volume of the crucible is ≈ 15 cm^3 and permits fusion of samples with a mass of up to 1 g. Samples are packed into a metal foil, loaded into a carousel, baked out before analysis, and then sequentially dropped into the Ta-crucible. The low weight of the crucible (≈ 120 g) allows for short and efficient degassing cycles. When the furnace is pumped for the first time after samples loading, short cycles between 500 and 1800 °C at fast heating rates (≈ 400 °C·min^(−1)) are sufficient to achieve very low blanks. The durations of these cycles are range from 30 min for He to up to a few hours for Ne, Kr and Xe. Blanks of He, Kr and Xe (10 min heating durations) and Ne (20 min) in static vacuum are (1.6 ± 1.0) × 10^(−15) mol ^4He (T = 1750 °C), (5.8 ± 2.3) × 10^(−17) mol ^(20)Ne (T = 1500 °C), (2.1 ± 0.3) × 10^(−18) mol ^(84)Kr (T = 1700 °C) and (4.4 ± 0.4) × 10^(−18) mol ^(132)Xe (T = 1700 °C). Argon blanks have not yet been measured

A new all-metal induction furnace for noble gas extraction

A new all-metal induction furnace for extraction of all noble gases from pyroxenes, olivines, quartz or barites has been developed at CRPG. It differs in design from other induction furnaces in that the totality of the vacuum vessel is metallic and the induction coil, normally located outside the furnace, has been placed inside the vacuum vessel, with a special radio frequency power feedthrough welded onto a flange. The volume of the crucible is ≈ 15 cm^3 and permits fusion of samples with a mass of up to 1 g. Samples are packed into a metal foil, loaded into a carousel, baked out before analysis, and then sequentially dropped into the Ta-crucible. The low weight of the crucible (≈ 120 g) allows for short and efficient degassing cycles. When the furnace is pumped for the first time after samples loading, short cycles between 500 and 1800 °C at fast heating rates (≈ 400 °C·min^(−1)) are sufficient to achieve very low blanks. The durations of these cycles are range from 30 min for He to up to a few hours for Ne, Kr and Xe. Blanks of He, Kr and Xe (10 min heating durations) and Ne (20 min) in static vacuum are (1.6 ± 1.0) × 10^(−15) mol ^4He (T = 1750 °C), (5.8 ± 2.3) × 10^(−17) mol ^(20)Ne (T = 1500 °C), (2.1 ± 0.3) × 10^(−18) mol ^(84)Kr (T = 1700 °C) and (4.4 ± 0.4) × 10^(−18) mol ^(132)Xe (T = 1700 °C). Argon blanks have not yet been measured

Nitrogen isotopes in the recent solar wind from the analysis of genesis targets: evidence for large scale isotope heterogeneity in the nascent solar system

Nitrogen, the fifth most abundant element in the universe, displays the largest stable isotope variations in the solar system reservoirs after hydrogen. Yet the value of isotopic composition of solar nitrogen, presumably the best proxy of the protosolar nebula composition, is not known. Nitrogen isotopes trapped in Genesis spacecraft target material indicate a 40 % depletion of {sup 15}N in solar wind N relative to inner planets and meteorites, and define a composition for the present-day Sun undistinguishable from that of Jupiter's atmosphere. These results indicate that the isotopic composition of of nitrogen in the outer convective zone of the Sun (OCZ) has not changed through time, and is representative of the protosolar nebula. Large {sup 15}N enrichments during e.g., irradiation, or contributions from {sup 15}N-rich presolar components, are required to account for planetary values

Tilapia male urinary pheromone stimulates female reproductive axis

Mozambique tilapia males congregate in leks where they establish dominance hierarchies and attract females to spawn in sandy pits. Dominant males store more urine than subordinates and the pattern of urination and the high sensitivity of females to male urine suggest chemical signalling via the urine. Here we show that pre-ovulated and post-spawn females when exposed to dominant male urine increased significantly, in less than 1 h, the release rate of the maturation-inducing steroid 17,20bdihydroxypregn- 4-en-3-one which is maintained elevated for at least 6 h. This indicates a pheromonal role for male urine in the synchronisation of spawning. Furthermore, we show that the lack of affinity of 17,20bP to sex steroid binding globulin explains, at least partly, its rapid release and lack of detection in the blood. Thus tilapia urine involvement in several communication processes confirms that cichlids have evolved a sophisticated chemical signalling system together with their complex visual, acoustic and behavioural displays

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Nitrogen isotopes in the recent solar wind from the analysis of Genesis targets: Evidence for large scale isotope heterogeneity in the early solar system

We have analyzed nitrogen, neon and argon abundances and isotopic ratios in target material exposed in space for 27 months to solar wind (SW) irradiation during the Genesis mission. SW ions were extracted by sequential UV (193 nm) laser ablation of gold-plated material, purified separately in a dedicated line, and analyzed by gas source static mass spectrometry. We analyzed gold-covered stainless steel pieces from the Concentrator, a device that concentrated SW ions by a factor of up to 50. Despite extensive terrestrial N contamination, we could identify a non-terrestrial, ^(15)N-depleted nitrogen end-member that points to a 40% depletion of ^(15)N in solar-wind N relative to inner planets and meteorites, and define a composition for the present-day Sun (^(15)N/^(14)N = [2.26 ± 0.67] × 10^(−3), 2σ), which is indistinguishable from that of Jupiter’s atmosphere. These results indicate that the isotopic composition of nitrogen in the outer convective zone of the Sun has not changed through time, and is representative of the protosolar nebula. Large ^(15)N enrichments due to e.g., irradiation, low temperature isotopic exchange, or contributions from ^(15)N-rich presolar components, are therefore required to account for inner planet values