Stony Brook University

About: Stony Brook University is a education organization based out in Stony Brook, New York, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 32534 authors who have published 68218 publications receiving 3035131 citations. The organization is also known as: State University of New York at Stony Brook & SUNY Stony Brook.

Evolution of Proto-Neutron Stars

Abstract: We study the thermal and chemical evolution during the Kelvin-Helmholtz phase of the birth of a neutron star, employing neutrino opacities that are consistently calculated with the underlying equation of state (EOS). Expressions for the diffusion coefficients appropriate for general relativistic neutrino transport in the equilibrium diffusion approximation are derived. The diffusion coefficients are evaluated using a field-theoretical finite-temperature EOS that includes the possible presence of hyperons. The variation of the diffusion coefficients is studied as a function of EOS and compositional parameters. We present results from numerical simulations of proto-neutron star cooling for internal stellar properties as well as emitted neutrino energies and luminosities. We discuss the influence of the initial stellar model, the total mass, the underlying EOS, and the addition of hyperons on the evolution of the proto-neutron star and on the expected signal in terrestrial detectors. We find that the differences in predicted luminosities and emitted neutrino energies do not depend much upon the details of the initial models or the underlying high-density EOS for early times (t<10 s), provided that opacities are calculated consistently with the EOS. The same holds true for models that allow for the presence of hyperons, except when the initial mass is significantly larger than the maximum mass for cold, catalyzed matter. For times larger than about 10 s, and prior to the occurrence of neutrino transparency, the neutrino luminosities decay exponentially with a time constant that is sensitive to the high-density properties of matter. We also find the average emitted neutrino energy increases during the first 5 s of evolution and then decreases nearly linearly with time. In general, increasing the proto-neutron star mass increases the average energy and the luminosity of neutrinos, as well as the overall evolutionary timescale. The influence of hyperons or variations in the dense matter EOS is increasingly important at later times. Metastable stars, those with hyperons that are unstable to collapse upon deleptonization, have relatively long evolution times, which increase the nearer the mass is to the maximum mass supportable by a cold, deleptonized star.

Transthyretin sequesters amyloid beta protein and prevents amyloid formation

Abstract: The cardinal pathological features of Alzheimer disease are depositions of aggregated amyloid beta protein (A beta) in the brain and cerebrovasculature. However, the A beta is found in a soluble form in cerebrospinal fluid in healthy individuals and patients with Alzheimer disease. We postulate that sequestration of A beta precludes amyloid formation. Failure to sequester A beta in Alzheimer disease may result in amyloidosis. When we added A beta to cerebrospinal fluid of patients and controls it was rapidly sequestered into stable complexes with transthyretin. Complexes with apolipoprotein E, which has been shown to bind A beta in vitro, were not observed in cerebrospinal fluid. Additional in vitro studies showed that both purified transthyretin and apolipoprotein E prevent amyloid formation.

Treatment of neuromyelitis optica with rituximab: retrospective analysis of 25 patients.

Abstract: Background: Neuromyelitis optica (NMO) is an uncommon, life-threatening inflammatory demyelinating disorder. Recently, much has become known about its immunopathogenesis. However, optimal treatments, with expected outcomes, have not been established. Objective: To evaluate the use and efficacy of rituximab for treating NMO. Design: Retrospective multicenter case series of NMO patients treated with rituximab. Setting: Seven tertiary medical centers in the United States and England. Patients: Twenty-five patients (including 2 children), 23 of whom experienced relapses despite use of other drugs before rituximab. Extended follow-up of 7 previously reported patients is included. Interventions: Infusions of rituximab at median intervals of 8 months. Main Outcome Measures: Annualized relapse rate and disability (expressed as Expanded Disability Status Scale score). Results: At a median follow-up of 19 months, the median annualized posttreatment relapse rate was lower than the pretreatment rate (0 [range 0-3.2] vs 1.7 [range, 0.5-5] relapses, P<.001). Disability improved or stabilized in 20 of 25 patients (80%, P=.02). Two patients died during the follow-up period, 1 owing to a brainstem relapse and 1 owing to suspected septicemia. Infections were reported in 20% of patients. Conclusions: In NMO, treatment with rituximab appears to reduce the frequency of attacks, with subsequent stabilization or improvement in disability.

Enhanced electrocatalytic performance of processed, ultrathin, supported Pd-Pt core-shell nanowire catalysts for the oxygen reduction reaction.

Abstract: We report on the synthesis, characterization, and electrochemical performance of novel, ultrathin Pt monolayer shell–Pd nanowire core catalysts. Initially, ultrathin Pd nanowires with diameters of 2.0 ± 0.5 nm were generated, and a method has been developed to achieve highly uniform distributions of these catalysts onto the Vulcan XC-72 carbon support. As-prepared wires are activated by the use of two distinctive treatment protocols followed by selective CO adsorption in order to selectively remove undesirable organic residues. Subsequently, the desired nanowire core–Pt monolayer shell motif was reliably achieved by Cu underpotential deposition followed by galvanic displacement of the Cu adatoms. The surface area and mass activity of the acid and ozone-treated nanowires were assessed, and the ozone-treated nanowires were found to maintain outstanding area and mass specific activities of 0.77 mA/cm2 and 1.83 A/mgPt, respectively, which were significantly enhanced as compared with conventional commercial Pt...