Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A

The nearby Supernova 1987A was accompanied by a burst of neutrino emission, which indicates that a compact object (a neutron star or black hole) was formed in the explosion. There has been no direct observation of this compact object. In this work, we observe the supernova remnant with JWST spectroscopy, finding narrow infrared emission lines of argon and sulfur. The line emission is spatially unresolved and blueshifted in velocity relative to the supernova rest frame. We interpret the lines as gas illuminated by a source of ionizing photons located close to the center of the expanding ejecta. Photoionization models show that the line ratios are consistent with ionization by a cooling neutron star or a pulsar wind nebula. The velocity shift could be evidence for a neutron star natal kick.

Illuminating gravitational waves: A concordant picture of photons from a neutron star merger

Merging neutron stars offer an excellent laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of an electromagnetic counterpart (EM170817) with gravitational waves (GW170817) detected from merging neutron stars. By synthesizing a panchromatic data set, we demonstrate that merging neutron stars are a long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma rays seen in EM170817 are dissimilar to classical short gamma-ray bursts with ultrarelativistic jets. Instead, we suggest that breakout of a wide-angle, mildly relativistic cocoon engulfing the jet explains the low-luminosity gamma rays, the high-luminosity ultraviolet-optical-infrared, and the delayed radio and x-ray emission. We posit that all neutron star mergers may lead to a wide-angle cocoon breakout, sometimes accompanied by a successful jet and sometimes by a choked jet.

Oxidation–reduction reactions of simple hydroxamic acids and plutonium(IV) ions in nitric acid

Simple hydroxamic acids such as formo- and aceto-hydroxamic acids have been proposed as suitable reagents for the separation of either Pu and/or Np from U in modified or single cycle Purex based solvent extraction processes designed to meet the emerging requirements of advanced fuel cycles. The stability of these hydroxamic acids is dominated by their decomposition through acid hydrolysis. Kinetic studies of the acid hydrolysis of formo- and aceto-hydroxamic acids are reported in the absence and the presence of Pu(IV) ions. The slow reduction of these plutonium(IV) hydroxamate complexes to Pu(III) aquo-ions has been characterised by spectrophotometry and cyclic voltammetry. The reductions of Pu(IV) in the presence of FHA and AHA are consistent with a mechanism in which free hydroxamic acid in solution is hydrolysed whilst Pu(IV) ions remain fully complexed to hydroxamate ligands; then at some point close to a 1 : 1 Pu(IV) : XHA ratio, some free Pu4+ is released from the complex and reduction is initiated. Electrochemical and kinetic data suggest that the reductant is the hydroxamic acid rather than the hydroxylamine.

The binding of difunctional neutral guest molecules by novel bis(tripyrrolyl) cryptands

Bis(tripyrrolyl) cryptands are prepared via a [2 + 3] Schiff base condensation of formyltripyrrolyls with diamines; an ethyl-spaced hexapyrrole cryptand is shown to bind strongly ethane-1,2-diamine and ethane-1,2-diol in chloroform solution.

Metal-assembled cobalt(II) resorc[4]arene-based cage molecules that reversibly capture organic molecules from water and act as NMR shift reagents

The complex Co4 1(2)8- is a tetranuclear cobalt(II) cage compound that assembles in aqueous solutions above pH 4 and is capable of encapsulating a variety of organic guest molecules, for example, benzene, hexane, chlorobutane, butanol, and ethyl acetate. Ligand 1 is a resorc[4]arene-based molecule with iminodiacetate moieties appended to its upper rim. 1H NMR studies of Co4 1(2)8-.guest complexes demonstrate inclusion of nonpolar hydrocarbons, substituted phenyls, alcohols, halogen-containing hydrocarbons, and polar organic molecules. The complex Co4 1(2)8- acts as an NMR shift reagent and causes substantial upfield isotropic hydrogen shifts (-30 to -40 ppm) in the guest molecule and separation of the guest hydrogen chemical shifts by typically 12 ppm. The complex Co4 1(2)8- will encapsulate molecules with fewer than eight atoms in a linear chain, mono- and disubstituted benzenes, and polar molecules with greater than two carbon atoms. The solid-state structure of Ba4[Co4 1(2).C6H5C2H5] shows a disordered guest molecule encapsulated within the cavity of Co4 1(2)8-. The cavity dimensions, bond lengths, and bond angles of Ba4[Co4 1(2).C6H5C2H5] are very similar to those determined in Ba4[Co4 1(2).6H2O].

Resorcarene-Based Nanoarchitectures: Metal-Directed Assembly of a Molecular Loop and Tetrahedron

Large cavities and portals are present in the nanoscale molecular architectures formed from dithiocarbamate-functionalized resorcarene ligands and zinc(II) or copper(III) ions. With Zn(II) a molecular loop based on a triangle of resorcarene cups is prepared-the cavity is circular (shown on the left). A molecular cage based on a distorted tetrahedron of four resorcarene ligands assembled by eight Cu(III) ions contains triangular-shaped portals suitable for guest passage (shown on the right).

Scoliosis after thoracotomy in tracheoesophageal fistula patients. A follow-up study

The cases of eighteen patients who underwent thoracotomy for treatment of tracheoesophageal fistula or esophageal atresia were reviewed after a follow-up of ten years or more. In nine patients spinal curves of 10 degrees or more had developed, and eight of the nine curves were convex away from the side of incision. Curves were found to have appeared at any time from early childhood to skeletal maturity, but those that developed before the adolescent growth spurt were most likely to progress. Patients who have undergone thoracotomy early in childhood should be watched carefully for the development of scoliosis.

Corticosteroid-induced avascular necrosis: an experimental study in rabbits

New Zealand white rabbits were divided into 4 groups for the study of the etiology of corticosteroid-induced osteonecrosis (avascular necrosis). Group A and B received intramuscular injections of methylprednisolone acetate and methylprednisolone succinate respectively. Group C, on semirestricted diets, and Group D, on ad libitum diets, were controls. Osteocyte death, necrotic debris and intravascular fat emboli were evident in sections of proximal and distal femur by the 2nd week in experimental animals. Blood analysis revealed elevated lipid and prostaglandin levels. Osteoporosis was first observed at 6 weeks. Evidence of advanced osteonecrosis was present histologically at 18 weeks. It is concluded that osteonecrosis probably develops as the result of the interaction of several corticosteroid-induced alterations, including circulating fat emboli and inflammatory unbound free fatty acids or prostaglandins. Osteoporosis may also be a factor in explaining the sporadic nature of the disorder.