Analysis of a High-Temperature Spectroscopic Gas Cell Design

Database parameters for line spectra are collected from many studies and require independent verification for use in the design and measurements of laser absorption spectroscopy systems. While many lower temperature lines are well characterized, the higher temperature and pressure lines found in studies of combustion products rely on theoretical scaling. High-temperature calibration devices are therefore desired to allow experimental validation of parameters under test conditions. For this research, the design of a high-temperature, three-zone gas cell is proposed as a replacement for the current absorption cell system at The University of Tennessee Space Institute (UTSI). This new design, a prototype of which has been built and tested at The Technical University of Denmark, allows for measurements of test gas samples at uniform temperatures of at least 1300K. A computational fluid dynamics (CFD) model is shown for the current UTSI gas cell that has \u3c6% difference with measured flange temperatures and \u3c7% dierence from axial gas temperature measurements. This CFD model is then used to predict material and centerline gas temperatures expected at the limit of the proposed design. The model results show that the proposed cell design has a high temperature uniformity in the test section and flange temperatures well below the temperature limits of the desired O-ring materials and indicate that water-cooling will be unnecessary

Giant convecting mud balls of the early solar system

Carbonaceous asteroids may have been the precursors to the terrestrial planets, yet despite their importance, numerous attempts to model their early solar system geological history have not converged on a solution. The assumption has been that hydrothermal alteration was occurring in rocky asteroids with material properties similar to meteorites. However, these bodies would have accreted as a high-porosity aggregate of igneous clasts (chondrules) and fine-grained primordial dust, with ice filling much of the pore space. Short-lived radionuclides melted the ice, and aqueous alteration of anhydrous minerals followed. However, at the moment when the ice melted, no geological process had acted to lithify this material. It would have been a mud, rather than a rock. We tested the effect of removing the assumption of lithification. We find that if the body accretes unsorted chondrules, then large-scale mud convection is capable of producing a size-sorted chondrule population (if the body accretes an aerodynamically sorted chondrule population, then no further sorting occurs). Mud convection both moderates internal temperature and reduces variation in temperature throughout the object. As the system is thoroughly mixed, soluble elements are not fractionated, preserving primitive chemistry. Isotopic and redox heterogeneity in secondary phases over short length scales is expected, as individual particles experience a range of temperature and water-rock histories until they are brought together in their final configuration at the end of convection. These results are consistent with observations from aqueously altered meteorites (CI and CM chondrites) and spectra of primitive asteroids. The “mudball” model appears to be a general solution: Bodies spanning a ×1000 mass range show similar behavior

The oxygen isotope evolution of parent body aqueous solutions as recorded by multiple carbonate generations in the Lonewolf Nunataks 94101 CM2 carbonaceous chondrite

The CM2 carbonaceous chondrite LON 94101 contains aragonite and two generations of calcite that provide snapshots of the chemical and isotopic evolution of aqueous solutions during parent body alteration. Aragonite was the first carbonate to crystallize. It is rare, heterogeneously distributed within the meteorite matrix, and its mean oxygen isotope values are δ18O 39.9±0.6‰, Δ17O -0.3±1.0‰ (1σ). Calcite precipitated very soon afterwards, and following a fall in solution Mg/Ca ratios, to produce small equant grains with a mean oxygen isotope value of δ18O 37.5±0.7‰, Δ17O 1.4±1.1‰ (1σ). These grains were partially or completely replaced by serpentine and tochilinite prior to precipitation of the second generation of calcite, which occluded an open fracture to form a millimeter-sized vein, and replaced anhydrous silicates within chondrules and the matrix. The vein calcite has a mean composition of δ18O 18.4±0.3‰, Δ17O -0.5±0.5‰ (1σ). Petrographic and isotopic results therefore reveal two discrete episodes of mineralization that produced Ca-carbonates with contrasting δ18O, but whose Δ17O values are indistinguishable within error. The aragonite and equant calcite crystallized over a relatively brief period early in the aqueous alteration history of the parent body, and from static fluids that were evolving chemically in response to mineral dissolution and precipitation. The second calcite generation crystallized from solutions of a lower Δ17O, and a lower δ18O and/or higher temperature, which entered LON 9410 via a fracture network. As two generations of calcite whose petrographic characteristics and oxygen isotopic compositions are similar to those in LON 94101 occur in at least one other CM2, multiphase carbonate mineralization could be the typical outcome of the sequence of chemical reactions during parent body aqueous alteration. It is equally possible however that the second generation of calcite in formed in response to an event such as impact fracturing and concomitant fluid mobilisation that affected a large region of the common parent body of several CM2 meteorites. These findings show that integrated petrographic, chemical and isotopic studies can provide new insights into the mechanisms of parent body alteration including the spatial and temporal dynamics of the aqueous system

B cell receptor accessory molecule CD79α : characterisation and expression analysis in a cartilaginous fish, the spiny dogfish (Squalus acanthias)

Copyright © 2013. Published by Elsevier Ltd.Peer reviewedPublisher PD

What Causes Stuttering?

The mystery of a sometimes debilitating speech disorder is examined by cognitive neuroscientist

Flatland

Flatland is a project of VCDE233 TYPOGRAPHY II and VCDI223 DESIGN AND PRE-PRESS PRODUCTION, both courses in the Design Studies diploma program at MacEwan University. Students were asked to translate an assigned section of the Victorian novella, Flatland: A Romance of Many Dimensions by Edwin A. Abbott (1884), into a two-page layout that treats the text in a way that is visually appealing, readable, and appropriate to the content. They were encouraged to challenge conventions by exploring alternative grids, objective and expressive type, and text and image relationships. VCDE233 Typography II (Constanza Pacher) and VCDI223 Design and Pre-Press Production (Jess Dupuis

Autologous stem cell transplantation with low-dose cyclophosphamide to improve mucosal healing in adults with refractory Crohn's disease: the ASTIClite RCT

Some text in this abstract has been reproduced from Lindsay J, Din S, Hawkey C, Hind D, Irving P, Lobo A, et al. OFR-9 An RCT of autologous stem-cell transplantation in treatment refractory Crohn’s disease (low-intensity therapy evaluation): ASTIClite. Gut 2021;70(Suppl. 4):A4. Background Treatment-refractory Crohn’s disease is characterised by chronic symptoms, poor quality of life and high costs to the NHS, and through days of work lost by patients. A previous trial of autologous haematopoietic stem cell transplant (HSCT) failed its end point of medication-free clinical remission for 3 months with no evidence of disease activity, and reported high toxicity. Subsequent studies suggest that HSCT achieves complete mucosal healing in 50% of patients, and that toxicity likely relates to the cyclophosphamide dose. Objectives The primary objective was to assess the efficacy of HSCTlite (HSCT with low-dose cyclophosphamide) compared with standard care for inducing regression of intestinal ulceration in patients with refractory Crohn’s disease at week 48. Secondary objectives included the assessment of disease activity, quality of life and regimen safety. Mechanistic objectives included immune reconstitution after HSCTlite. Design Two-arm, parallel-group randomised controlled trial with a 2 : 1 (intervention : control) allocation ratio. Setting Nine NHS trusts (eight trusts were recruitment sites; one trust was a treatment-only site). Participants Adults with treatment-refractory Crohn’s disease, for whom surgery was inappropriate or who had declined surgery. Interventions The intervention treatment was HSCTlite using cyclophosphamide, and the control was any current available treatment for Crohn’s disease, apart from stem cell transplantation. Main outcomes The primary outcome was treatment success at week 48 [mucosal healing (Simple Endoscopic Score for Crohn’s Disease ulcer subscore of 0) without surgery or death], assessed by central readers blinded to allocation and timing of assessment. Key secondary outcomes were clinical remission, Simple Endoscopic Score for Crohn’s Disease scores at week 48, change in Crohn’s Disease Activity Index scores and safety. Results The trial was halted owing to Suspected unexpected serious adverse events that took place after randomising 23 patients (HSCTlite arm, n = 13; usual-care arm, n = 10). Ten out of the 13 patients randomised to the HSCTlite arm received the intervention and nine (one death) reached the 48-week follow-up. In the usual-care arm 9 out of the 10 patients randomised reached the 48-week follow-up (one ineligible). The primary outcome was available for 7 out of 10 HSCTlite patients (including the patient who died) and six out of nine usual-care patients. Absence of endoscopic ulceration without surgery or death was reported in three out of seven (43%) HSCTlite patients, compared with zero out of six (0%) usual-care patients. Centrally read Simple Endoscopic Score for Crohn’s Disease scores [mean (standard deviation)] were 10.8 (6.3) and 10.0 (6.1) at baseline, compared with 2.8 (2.9) and 18.7 (9.1) at week 48, in the HSCT and usual-care arms, respectively. Clinical remission (Crohn’s Disease Activity Index scores of < 150) occurred in 57% and 17% of patients in the HSCTlite and usual-care arms, respectively, at week 48. Serious adverse events were more frequent in the HSCTlite arm [38 in 13 (100%) patients] than in the usual-care arm [16 in 4 (40%) patients]. Nine suspected unexpected serious adverse reactions were reported in six HSCTlite patients, including three cases of delayed renal failure due to proven thrombotic microangiopathy. Two HSCTlite patients died. Conclusions Within the limitations of reduced patient recruitment and numbers of patients assessed, HSCTlite meaningfully reduced endoscopic disease activity, with three patients experiencing resolution of ulceration. Suspected unexpected serious adverse reactions, particularly relating to thrombotic microangiopathy, make this regimen unsuitable for future clinical use. Limitations The early trial closure prevented complete recruitment, and the impact of the coronavirus pandemic prevented completion of some study investigations. Small participant numbers meant analysis could only be descriptive. Future work Owing to undetermined aetiology of thrombotic microangiopathy, further trials of HSCTlite in this population are not considered appropriate. Priorities should be to determine optimal treatment strategies for patients with refractory Crohn’s disease, including those with a stoma or multiple previous resections

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

Multi-ancestry meta-analysis of tobacco use disorder prioritizes novel candidate risk genes and reveals associations with numerous health outcomes

Tobacco use disorder (TUD) is the most prevalent substance use disorder in the world. Genetic factors influence smoking behaviors, and although strides have been made using genome-wide association studies (GWAS) to identify risk variants, the majority of variants identified have been for nicotine consumption, rather than TUD. We leveraged five biobanks to perform a multi-ancestral meta-analysis of TUD (derived via electronic health records, EHR) in 898,680 individuals (739,895 European, 114,420 African American, 44,365 Latin American). We identified 88 independent risk loci; integration with functional genomic tools uncovered 461 potential risk genes, primarily expressed in the brain. TUD was genetically correlated with smoking and psychiatric traits from traditionally ascertained cohorts, externalizing behaviors in children, and hundreds of medical outcomes, including HIV infection, heart disease, and pain. This work furthers our biological understanding of TUD and establishes EHR as a source of phenotypic information for studying the genetics of TUD