High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suite Gas Processing System (GPS) Carbon Dioxide Scrubber

In support of the GPS for the SAM instrument suite built by NASA/GSFC, a life test facility was developed to test the suitability of 80Ni-20Cr alloy wire, 0.0142 cm diameter, for use as a heater element for the carbon dioxide scrubber. The element would be required to operate at 1000 C in order to attain the 800 C required for regeneration of the getter. The element also would need to operate in the Mars atmosphere, which consists mostly of CO2 at pressures between 4 and 12 torr. Data on the high temperature degradation mechanism of 80Ni- 20Cr in low pressure CO2, coupled with the effects of thermal cycling, were unknown. In addition, the influence of work hardening of the wire during assembly and the potential for catastrophic grain growth also were unknown. Verification of the element reliability as defined by the mission goals required the construction of a test facility that would accurately simulate the duty cycles in a simulated Mars atmosphere. The experimental set-up, along with the test protocol and results will be described

Resistively Heated SiC Nozzle for Generating Molecular Beams

An improved nozzle has been developed to replace nozzles used previously in an apparatus that generates a substantially unidirectional beam of molecules passing through a vacuum at speeds of several kilometers per second. The basic principle of operation of the apparatus is the same for both the previous and the present nozzle designs. The main working part of the nozzle is essentially a cylinder that is closed except that there is an inlet for a pressurized gas and, at one end, the cylinder is closed by a disk that contains a narrow central hole that serves as an outlet. The cylinder is heated to increase the thermal speeds of the gas molecules into the desired high-speed range. Heated, pressurized gas escapes through the outlet into a portion of the vacuum chamber that is separated, by a wall, from the rest of the vacuum chamber. In this portion of the vacuum chamber, the gas undergoes a free jet expansion. Most of the expanded gas is evacuated and thus does not become part of the molecular beam. A small fraction of the expanded beam passes through a narrow central orifice in the wall and thereby becomes a needle- thin molecular beam in the portion of the vacuum on the downstream side of the wall

The burden of childhood atopic dermatitis in the primary care setting: a report from the Meta-LARC Consortium

Background: Little is known about the burden of AD encountered in U.S. primary care practices and the frequency and type of skin care practices routinely used in children. Objectives: To estimate the prevalence of AD and allergic comorbidities in children 0-5 years attending primary care practices in the U.S. and to describe routine skin care practices used in this population. Design: A cross-sectional survey study of a convenience sample of children under the age of 5 attending primary care practices for any reason. Setting: Ten primary care practices in five U.S. states.Results: Amongst 652 children attending primary care practices, the estimated prevalence of ever having AD was 24 % (95% CI= 21-28) ranging from 15% among those under the age of one to 38% among those aged 4- 5 years. The prevalence of comorbid asthma was higher among AD participants compared to those with no AD, 12% and 4%, respectively (p less than 0.001). Moisturizers with high water:oil ratios were most commonly used (i.e., lotions) in the non-AD population, whereas moisturizers with low water:oil content (i.e. ointments) most common when AD was present. Conclusions: Our study found a large burden of AD in the primary care practice setting in the U.S. The majority of households reported skin care practices in children without AD that may be detrimental to the skin barrier such as frequent bathing and the routine use of moisturizers with high water: oil ratios. Clinical trials are needed to identify which skin care practices are optimal for reducing the significant risk of AD in the community

CORALS: A Laser Desorption/Ablation Orbitrap Mass Spectrometer for In Situ Exploration of Europa

International audienc

Laser desorption mass spectrometry with an Orbitrap analyser for in situ astrobiology

Laser desorption mass spectrometry (LDMS) enables in situ characterization of the organic content and chemical composition of planetary materials without requiring extensive sample processing. Coupled with an Orbitrap TM analyzer capable of ultrahigh mass resolving powers and accuracies, LDMS techniques facilitate the orthogonal detection of a wide range of prospective biomarkers and classification of host mineralogy. Here, an Orbitrap LDMS instrument that has been miniaturized for planetary exploration is shown to meet the performance standards of commercial systems and exceed key figures of merit of heritage spaceflight technologies, including those baselined for nearterm mission opportunities. Biogenic compounds at area densities relevant to prospective missions to ocean worlds are identified unambiguously by redundant measurements of molecular ions (with and without salt adducts) and diagnostic fragments. The derivation of collision cross-sections serves to corroborate assignments and inform on molecular structure. Access to trace elements down to ppmw levels provide insights into geological context

Planetary Applications For In Situ Laser Ablation Processing Coupled With Mass Spectrometry

International audienceOver the next few decades, top-level planetary mission objectives will pivot towards the in situ chemical analysis of silicate- and/or ice-rich bodies in order to augment our understanding of: i) planetary geology, informing on processes such as protracted accretion, internal differentiation, and interior dynamics; ii) prospects for habitability and biosignature preservation potential of surface and subsurface environments; and ultimately, iii) the detection of organic matter and identification of alien biological systems (if present). Lander and rover platforms continue to become more enabling, offering expanded payload capacities (i.e., more mass, volume, and energy resources for instruments), drills capable of acquiring materials from depths at the km-scale, and precision sample manipulation with advanced robotic systems. Mission concepts that incorporate elements of both fundamental geology and astrobiology are highly prioritized by the scientific community, NASA Science Mission Directorate, and ESA Cosmic Vision Program; viable mission candidates include comet, asteroid, and/or lunar sample return, and the progressive exploration of Mars and its moons. The addition of "Ocean Worlds" to the New Frontiers 4 Announcement of Opportunity served to underscore the critical need for in situ chemical analyzers capable of characterizing solid planetary materials, such as salts, ices, and sublimated residues (in addition to more traditional silicate minerals and accessory phases). The M-CLASS (Measurement of Composition via Laser Ablation Sampling and Spectrometry) Laboratory, a joint venture between the University of Maryland, NASA GSFC, and international partners, is advancing a number of pioneering technologies geared specifically towards analyzing elemental composition, isotopic abundances, and organic content of solid planetary materials via in situ laser ablation mass spectrometry. For geological investigations, a miniaturized inductively coupled plasma mass spectrometer (ICPMS) equipped with a heritage quadrupole mass analyzer (a la the SAM QMS) is in development. The innovative plasma source, which was designed originally through the NASA SBIR Program, requires as little as 1 W of power (tunable per science requirements) but provides access to trace element signals. Because trace elements (defined by abundances at ppmw levels or below) are too depleted to form accessory phases, they can vary by more than three orders of magnitude in geological samples and serve as sensitive tracers to a host of planetary processes (global differentiation, weathering/erosion, biomineralization, etc.). For astrobiological investigations, we are building and qualifying for spaceflight an engineering model of a laser-enabled Orbitrap mass analyzer capable of detecting organic compounds and contextual mineralogical indicators via high sensitivity and active beam scanning, resulting in 2D chemical imaging without extensive sample handling requirements. A prototype version of this instrument has been shown to distinguish organic molecules as potential biomarkers with ultrahigh mass resolution (m/Δm ≥ 120,000, FWHM at m/z 100) and highly accurate peak assignments within 3 ppm of absolute values. The quantification of isotopic abundances with ≤1.0% (2σ) precision, and the detection of a variety of amino acids at concentrations as low as ≤1 pmol/mm2, were also demonstrated

Planetary Applications For In Situ Laser Ablation Processing Coupled With Mass Spectrometry

International audienceOver the next few decades, top-level planetary mission objectives will pivot towards the in situ chemical analysis of silicate- and/or ice-rich bodies in order to augment our understanding of: i) planetary geology, informing on processes such as protracted accretion, internal differentiation, and interior dynamics; ii) prospects for habitability and biosignature preservation potential of surface and subsurface environments; and ultimately, iii) the detection of organic matter and identification of alien biological systems (if present). Lander and rover platforms continue to become more enabling, offering expanded payload capacities (i.e., more mass, volume, and energy resources for instruments), drills capable of acquiring materials from depths at the km-scale, and precision sample manipulation with advanced robotic systems. Mission concepts that incorporate elements of both fundamental geology and astrobiology are highly prioritized by the scientific community, NASA Science Mission Directorate, and ESA Cosmic Vision Program; viable mission candidates include comet, asteroid, and/or lunar sample return, and the progressive exploration of Mars and its moons. The addition of "Ocean Worlds" to the New Frontiers 4 Announcement of Opportunity served to underscore the critical need for in situ chemical analyzers capable of characterizing solid planetary materials, such as salts, ices, and sublimated residues (in addition to more traditional silicate minerals and accessory phases). The M-CLASS (Measurement of Composition via Laser Ablation Sampling and Spectrometry) Laboratory, a joint venture between the University of Maryland, NASA GSFC, and international partners, is advancing a number of pioneering technologies geared specifically towards analyzing elemental composition, isotopic abundances, and organic content of solid planetary materials via in situ laser ablation mass spectrometry. For geological investigations, a miniaturized inductively coupled plasma mass spectrometer (ICPMS) equipped with a heritage quadrupole mass analyzer (a la the SAM QMS) is in development. The innovative plasma source, which was designed originally through the NASA SBIR Program, requires as little as 1 W of power (tunable per science requirements) but provides access to trace element signals. Because trace elements (defined by abundances at ppmw levels or below) are too depleted to form accessory phases, they can vary by more than three orders of magnitude in geological samples and serve as sensitive tracers to a host of planetary processes (global differentiation, weathering/erosion, biomineralization, etc.). For astrobiological investigations, we are building and qualifying for spaceflight an engineering model of a laser-enabled Orbitrap mass analyzer capable of detecting organic compounds and contextual mineralogical indicators via high sensitivity and active beam scanning, resulting in 2D chemical imaging without extensive sample handling requirements. A prototype version of this instrument has been shown to distinguish organic molecules as potential biomarkers with ultrahigh mass resolution (m/Δm ≥ 120,000, FWHM at m/z 100) and highly accurate peak assignments within 3 ppm of absolute values. The quantification of isotopic abundances with ≤1.0% (2σ) precision, and the detection of a variety of amino acids at concentrations as low as ≤1 pmol/mm2, were also demonstrated

CORALS: A Laser Desorption/Ablation Orbitrap Mass Spectrometer for In Situ Exploration of Europa

International audienc