Design of Optical/IR Blocking Filters for the Lynx X-Ray Microcalorimeter

The Lynx mission concept, under development ahead of the 2020 Astrophysics Decadal Review, includes the Lynx X-ray Microcalorimeter (LXM) as one of its primary instruments. The LXM uses a microcalorimeter array at the focus of a high-throughput soft x-ray telescope to enable high-resolution nondispersive spectroscopy in the soft x-ray waveband (0.2 to 15 keV) with exquisite angular resolution. Similar to other x-ray microcalorimeters, the LXM uses a set of blocking filters mounted within the dewar that pass the photons of interest (x-rays) while attenuating the out-of-band long-wavelength radiation. Such filters have been successfully used on previous orbital and suborbital instruments; however, the Lynx science objectives, which emphasize observations in the soft x-ray band (<1keV), pose more challenging requirements on the set of LXM blocking filters. We present an introduction to the design of the LXM optical/IR blocking filters and discuss recent advances in filter capability targeted at LXM. In addition, we briefly describe the external filters and the modulated x-ray sources to be used for onboard detector calibration

Formaldehyde Anti-Inversion at z=0.68 in the Gravitational Lens B0218+357

We report new observations of the 110-111 (6 cm) and 211-212 (2 cm) transitions of ortho-formaldehyde (o-H2CO) in absorption at z=0.68466 toward the gravitational lens system B0218+357. Radiative transfer modeling indicates that both transitions are anti-inverted relative to the 4.6 K cosmic microwave background (CMB), regardless of the source covering factor, with excitation temperatures of ~1 K and 1.5-2 K for the 110-111 and 211-212 lines, respectively. Using these observations and a large velocity gradient radiative transfer model that assumes a gradient of 1 km s^-1 pc^-1, we obtain a molecular hydrogen number density of 2x10^3 cm^-3 < n(H2) < 1x10^4 cm^-3 and a column density of 2.5x10^13 cm^-2 < N(o-H2CO) < 8.9x10^13 cm^-2, where the allowed ranges conservatively include the range of possible source covering factors in both lines. The measurements suggest that H2CO excitation in the absorbing clouds in the B0218+357 lens is analogous to that in Galactic molecular clouds: it would show H2CO absorption against the CMB if it were not illuminated by the background quasar or if it were viewed from another direction.Comment: 10 pages, 6, figures, 6 table

Enhanced electrochemical energy storage by nanoscopic decoration of endohedral and exohedral carbon with vanadium oxide via atomic layer deposition

Atomic layer deposition (ALD) is a facile process to decorate carbon surfaces with redox-active nanolayers. This is a particularly attractive route to obtain hybrid electrode materials for high performance electrochemical energy storage applications. Using activated carbon and carbon onions as representatives of substrate materials with large internal or external surface area, respectively, we have studied the enhanced energy storage capacity of vanadium oxide coatings. While the internal porosity of activated carbon readily becomes blocked by obstructing nanopores, carbon onions enable the continued deposition of vanadia within their large interparticle voids. Electrochemical benchmarking in lithium perchlorate in acetonitrile (1 M LiClO4) showed a maximum capacity of 122 mAh/g when using vanadia coated activated carbon and 129 mAh/g for vanadia coated carbon onions. There is an optimum amount of vanadia between 50 and 65 wt % for both substrates that results in an ideal balance between redox-activity and electrical conductivity of the hybrid electrode. Assembling asymmetric (charge balanced) full-cells, a maximum specific energy of 38 Wh/kg and 29 Wh/kg was found for carbon onions and activated carbon, respectively. The stability of both systems is promising, with a capacity retention of ∼85–91% after 7000 cycles for full-cell measurements

PE-46 The Design of the Lynx X-Ray Microcalorimeter

Lynx is an x-ray telescope, one of four large satellite mission concepts currently being studied by NASA to be the next astrophysics flagship mission after WFIRST. One of Lynx's three instruments is an imaging spectrometer consisting of an x-ray microcalorimeter behind an X-ray optic with an angular resolution of 0.5 arc-seconds and approximately 3 sq m of area at 1 keV. This instrument will provide unparalleled diagnostics of distant extended structures and in particular will allow the detailed study of the role of cosmic feedback in the evolution of the Universe. We discuss the design and read-out of the of the array configuration including a number of sub-array options for increasing the capabilities to maximize the scientific return of the Lynx observatory

Classification of childhood asthma phenotypes and long-term clinical responses to inhaled anti-inflammatory medications

Background— Although recent studies have identified the presence of phenotypic clusters in asthmatic patients, the clinical significance and temporal stability of these clusters have not been explored. Objective— Our aim was to examine the clinical relevance and temporal stability of phenotypic clusters in children with asthma. Methods— We applied spectral clustering to clinical data from 1041 children with asthma participating in the Childhood Asthma Management Program. Posttreatment randomization follow-up data collected over 48 months were used to determine the effect of these clusters on pulmonary function and treatment response to inhaled anti-inflammatory medication. Results— We found 5 reproducible patient clusters that could be differentiated on the basis of 3 groups of features: atopic burden, degree of airway obstruction, and history of exacerbation. Cluster grouping predicted long-term asthma control, as measured by the need for oral prednisone (P < .0001) or additional controller medications (P = .001), as well as longitudinal differences in pulmonary function (P < .0001). We also found that the 2 clusters with the highest rates of exacerbation had different responses to inhaled corticosteroids when compared with the other clusters. One cluster demonstrated a positive response to both budesonide (P = .02) and nedocromil (P = .01) compared with placebo, whereas the other cluster demonstrated minimal responses to both budesonide (P = .12) and nedocromil (P = .56) compared with placebo. Conclusion— Phenotypic clustering can be used to identify longitudinally consistent and clinically relevant patient subgroups, with implications for targeted therapeutic strategies and clinical trials design

ITGB5 and AGFG1 variants are associated with severity of airway responsiveness

Background: Airway hyperresponsiveness (AHR), a primary characteristic of asthma, involves increased airway smooth muscle contractility in response to certain exposures. We sought to determine whether common genetic variants were associated with AHR severity. Methods: A genome-wide association study (GWAS) of AHR, quantified as the natural log of the dosage of methacholine causing a 20% drop in FEV1, was performed with 994 non-Hispanic white asthmatic subjects from three drug clinical trials: CAMP, CARE, and ACRN. Genotyping was performed on Affymetrix 6.0 arrays, and imputed data based on HapMap Phase 2, was used to measure the association of SNPs with AHR using a linear regression model. Replication of primary findings was attempted in 650 white subjects from DAG, and 3,354 white subjects from LHS. Evidence that the top SNPs were eQTL of their respective genes was sought using expression data available for 419 white CAMP subjects. Results: The top primary GWAS associations were in rs848788 (P-value 7.2E-07) and rs6731443 (P-value 2.5E-06), located within the ITGB5 and AGFG1 genes, respectively. The AGFG1 result replicated at a nominally significant level in one independent population (LHS P-value 0.012), and the SNP had a nominally significant unadjusted P-value (0.0067) for being an eQTL of AGFG1. Conclusions: Based on current knowledge of ITGB5 and AGFG1, our results suggest that variants within these genes may be involved in modulating AHR. Future functional studies are required to confirm that our associations represent true biologically significant findings

The Vitamin D Antenatal Asthma Reduction Trial (VDAART): Rationale, design, and methods of a randomized, controlled trial of vitamin D supplementation in pregnancy for the primary prevention of asthma and allergies in children

There is intense interest in the role of vitamin D in the development of asthma and allergies. However, studies differ on whether a higher vitamin D intake or status in pregnancy or at birth is protective against asthma and allergies. To address this uncertainty, the Vitamin D Antenatal Asthma Reduction Trial (VDAART) was developed. VDAART is a randomized, double-blind, placebo-controlled trial of vitamin D supplementation in pregnant women to determine whether prenatal supplementation can prevent the development of asthma and allergies in the women’s offspring. A secondary aim is to determine whether vitamin D supplementation can prevent the development of pregnancy complications, such as preeclampsia, preterm birth, and gestational diabetes. Women were randomized to the treatment arm of 4,000 IU/day of vitamin D3 plus a daily multivitamin that contained 400 IU of vitamin D3 or the placebo arm of placebo plus a multivitamin that contained 400 IU daily of vitamin D3. Women who were between the gestational ages of 10–18 weeks were randomized from three clinical centers across the United States – Boston Medical Center, Washington University in St. Louis, and Kaiser Permanente Southern California Region (San Diego, CA). Supplementation took place throughout pregnancy. Monthly monitoring of urinary calcium to creatinine ratio was performed in addition to medical record review for adverse events. Offspring are being evaluated quarterly through questionnaires and yearly during in-person visits until the 3rd birthday of the child. Ancillary studies will investigate neonatal T-regulatory cell function, maternal vaginal flora, and maternal and child intestinal flora

Patterns of Growth and Decline in Lung Function in Persistent Childhood Asthma

BACKGROUND: Tracking longitudinal measurements of growth and decline in lung function in patients with persistent childhood asthma may reveal links between asthma and subsequent chronic airflow obstruction. METHODS: We classified children with asthma according to four characteristic patterns of lung-function growth and decline on the basis of graphs showing forced expiratory volume in 1 second (FEV1), representing spirometric measurements performed from childhood into adulthood. Risk factors associated with abnormal patterns were also examined. To define normal values, we used FEV1 values from participants in the National Health and Nutrition Examination Survey who did not have asthma. RESULTS: Of the 684 study participants, 170 (25%) had a normal pattern of lung-function growth without early decline, and 514 (75%) had abnormal patterns: 176 (26%) had reduced growth and an early decline, 160 (23%) had reduced growth only, and 178 (26%) had normal growth and an early decline. Lower baseline values for FEV1, smaller bronchodilator response, airway hyperresponsiveness at baseline, and male sex were associated with reduced growth (P<0.001 for all comparisons). At the last spirometric measurement (mean [±SD] age, 26.0±1.8 years), 73 participants (11%) met Global Initiative for Chronic Obstructive Lung Disease spirometric criteria for lung-function impairment that was consistent with chronic obstructive pulmonary disease (COPD); these participants were more likely to have a reduced pattern of growth than a normal pattern (18% vs. 3%, P<0.001). CONCLUSIONS: Childhood impairment of lung function and male sex were the most significant predictors of abnormal longitudinal patterns of lung-function growth and decline. Children with persistent asthma and reduced growth of lung function are at increased risk for fixed airflow obstruction and possibly COPD in early adulthood. (Funded by the Parker B. Francis Foundation and others; ClinicalTrials.gov number, NCT00000575.