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Transmission spectroscopy1–3of exoplanets has revealed signatures of water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations’ relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species—in particular the primary carbon-bearing molecules6,7. Here we report a broad-wavelength 0.5–5.5 µm atmospheric transmission spectrum of WASP-39b8, a 1,200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with the JWST NIRSpec’s PRISM mode9as part of the JWST Transiting Exoplanet Community Early Release Science Team Program10–12. We robustly detect several chemical species at high significance, including Na (19σ), H2O (33σ), CO2(28σ) and CO (7σ). The non-detection of CH4, combined with a strong CO2feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4 µm is best explained by SO2(2.7σ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST’s sensitivity to a rich diversity of exoplanet compositions and chemical processes.

This retrospective analysis studied the effect of sclerotherapy on subsequent oesophageal transection in the management of patients with bleeding oesophageal varices and compared the result with that in those who did not receive sclerotherapy as the primary treatment. Fifty patients were treated by gastro-oesophageal devascularization and oesophageal transection for bleeding oesophageal varices over a 4-year period. Twenty-six patients did not receive sclerotherapy (group 1) and 24 received between one and four sessions of sclerotherapy (group 2) before surgery. Oedema and thickness of the lower end of the oesophagus and some adhesions were noted during surgery in patients who had had previous sclerotherapy; however, stapled oesophageal transection and anastomosis could be performed in all these patients. There was no oesophageal leak in any patient, although there was a higher rate of chest complications (nine versussix patients) in group 2. Six patients (12 per cent) died (three in each group) during the postoperative period; three had Child grade C disease. It is concluded that the decision to operate to control bleeding varices should be made early. One or two sessions of sclerotherapy before surgery does not increase intraoperative difficulty or the postoperative leak rate following oesophageal transection. The outcome of surgery is directly related to the state of liver reserve (Child grade).

A simulation was carried out to study the Chemical Vapor Deposition (CVD) of SiC on a thin cylindrical substrate in a hot wall reactor. The results of this simulation are expected to apply to the process of fiber coating for interface control in fiber reinforced composites. The reactant in this study is methyltrichlorosilane (CH3SiCl3) in a background of hydrogen. The simulation was carried out using a commercial code (FLUENT). The simulation results compared well with experimental data from a hot wall reactor. It was determined that the temperature profiles tend to be uniform in the radial direction, and the deposition process is dominated by reaction kinetics.

The development of temperature gradients and thermal stresses during the heating of large ingots has been investigated with special reference to the selection of heating schedules for brittle intermetallic materials such as titanium aluminides. A 1-D analytical (series) solution for radial temperature transients was used in conjunction with an elasticity analysis to determine the maximum thermal stresses that would be generated during ingot heating. The temperature gradients and stresses were seen to be strongly dependent on Fourier and Biot Numbers. In addition, finite element method simulations incorporating end effects and variations of thermal and elastic properties with temperature were performed and compared to the analytical results. Comparison of the predicated thermal stresses and actual ingot heating observations suggest that cracking is controlled by a maximum normal stress criterion.

The development of temperature gradients and thermal stresses during the heating of large ingots has been investigated with special reference to the selection of heating schedules for brittle intermetallic materials such as titanium aluminides. A 1-D analytical (series) solution for radial temperature transients was used in conjunction with an elasticity analysis to determine the maximum thermal stresses that would be generated during ingot heating. The temperature gradients and stresses were seen to be strongly dependent on Fourier and Biot Numbers. In addition, finite element method simulations incorporating end effects and variations of thermal and elastic properties with temperature were performed and compared to the analytical results. Comparison of the predicated thermal stresses and actual ingot heating observations suggest that cracking is controlled by a maximum normal stress criterion.

Thermophysical properties (thermal conductivity, thermal diffusivity, and specific heat) of porous alpha-two titanium autminide compacts are measured by a laser flash measurement technique. The experimentally measured properties are compared with some of the available models in the relative density range 0.7 to 1.0. Thermal property data available in the literature for porous stainless steel, brass, and beryllium oxide compacts are also compared with the models. Some of the limitations of the existing models to predict the thermal properties as a Junction of relative density (or porosity) are discussed.

Outside vapor deposition has been studied experimentally, and the deposition process parameters have been examined. The system consisted of an industrial-type burner and a cylindrical bait rod. The following aspects of this process were studied: 1) the temperature profile of the bait rod surface, 2) the deposition efficiency measured in terms of the mass of deposited SiO2, and 3) the size distribution of the deposited particles. The maximum bait rod surface temperature was, as expected, at the stagnation point. The temperature on the surface dropped rapidly along the axis of the bait rod away from the stagnation point; this is expected to influence the thermophoretic deposition rate. The particle size distribution shows that the particle diameters are near 0.2 μm and above.

A new type of aerosol reactor is described. By controlling the rate of gas phase reactions such that vapor diffusion to existing particles is favored over homogeneous nucleation, a small number of seed particles can be grown to supermicron sizes. A model for the influence of growing particles on the rate of homogeneous nucleation has been used to design a reactor for the production of silicon particles by thermal decomposition of silane gas. Particles as large as 9 μm mass median diameter have been grown in this two-stage reactor. Silicon aerosol yields ranging from 70% to 83% have been achieved with this system.

The homogenization of ingot metallurgy near-gamma titanium aluminides was investigated with respect to the kinetics of dissolution of single-phase gamma grains during heat treatment in the alpha phase field as well the determination of a processing window for use in scaleup of such heat treatments for large production billets. Initially, homogenization treatments were conducted using small samples heated in a highly controllable, low thermal inertia heating device. Post heat-treatment metallography and microprobe analysis quantified the kinetics of dissolution and suggested that a reaction at the interface between the remnant gamma grains and the surrounding alpha matrix controlled homogenization. A reasonable fit to the measured kinetics was obtained by assuming a reaction rate proportional to the square of the difference between (1) the maximum possible aluminum concentration in the alpha phase in equilibrium with the gamma phase and (2) the actual aluminum concentration in the alpha phase during the dissolution process. Scaleup feasibility was established using both an approximate closed-form analytical solution and finite difference method calculations for the heating of round cylinders of various sizes and height-to-diameter ratios. The surface-to-center temperature differences derived from such calculations were used in conjunction with the measured homogenization kinetics to establish heating cycles that would produce homogenization of the entire billet while minimizing grain growth and exposure time at high temperature.

We have developed an enzyme-linked immunosorbent assay for quantitating human immunoglobulin A in human secretions and serum. The procedure uses Immunobeads as the solid phase, has a sensitivity of 10 ng/ml, and can be completed in 1 day. Since there is no diffusion through agar, the assay does not require a correction factor when measuring secretory immunoglobulin A. This method should be useful in studies of local mucosal immunity in humans, especially when a very sensitive assay is needed.

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