Strong neutrino cooling by cycles of electron capture and β- decay in neutron star crusts.

The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, β(-) decay, involving neutron-rich nuclei at a typical depth of about 150 metres, cool the outer neutron star crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust.

Neutron single particle structure in 131Sn and direct neutron capture cross sections.

Recent calculations suggest that the rate of neutron capture by (130)Sn has a significant impact on late-time nucleosynthesis in the r process. Direct capture into low-lying bound states is expected to be significant in neutron capture near the N=82 closed shell, so r-process reaction rates may be strongly impacted by the properties of neutron single particle states in this region. In order to investigate these properties, the (d,p) reaction has been studied in inverse kinematics using a 630 MeV beam of (130)Sn (4.

Time-of-flight mass measurements for nuclear processes in neutron star crusts.

We present results from time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory that are relevant for neutron star crust models. The masses of 16 neutron-rich nuclei in the scandium-nickel range were determined simultaneously, with the masses of (61)V, (63)Cr, (66)Mn, and (74)Ni measured for the first time with mass excesses of -30.510(890) MeV, -35.

Nano- and sub-micron porous polyelectrolyte multilayer assemblies: biomimetic surfaces for human corneal epithelial cells.

In vivo, corneal epithelial cells adhere on basement membranes that exhibit porosity on the nanoscale with the diameters of pores and fibers ranging from 20 to 200 nm. Polyelectrolyte multilayers with porosity ranging from the nano to the microscale were assembled to mimic the pore sizes of corneal membranes in vivo. The average pore diameter was found to be 100 nm and 600 nm for the nanoporous and sub-micron porous films respectively.

Effects of inelastic neutrino-nucleus scattering on supernova dynamics and radiated neutrino spectra.

Based on the shell model for Gamow-Teller and the random phase approximation for forbidden transitions, we calculate cross sections for inelastic neutrino-nucleus scattering (INNS) under supernova (SN) conditions, assuming a matter composition given by nuclear statistical equilibrium. The cross sections are incorporated into state-of-the-art stellar core-collapse simulations with detailed energy-dependent neutrino transport. While no significant effect on the SN dynamics is observed, INNS increases the neutrino opacities noticeably and strongly reduces the high-energy tail of the neutrino spectrum emitted in the neutrino burst at shock breakout.

Neutrino-induced nucleosynthesis of A>64 nuclei: the nu p process.

We present a new nucleosynthesis process that we denote as the nu p process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this process, antineutrino absorptions in the proton-rich environment produce neutrons that are immediately captured by neutron-deficient nuclei. This allows for the nucleosynthesis of nuclei with mass numbers A>64, , making this process a possible candidate to explain the origin of the solar abundances of (92,94)Mo and (96,98)Ru.

Consequences of nuclear electron capture in core collapse supernovae.

The most important weak nuclear interaction to the dynamics of stellar core collapse is electron capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, electron capture on these nuclei has been treated in a highly parametrized fashion, if not ignored. With realistic treatment of electron capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce.

Electron capture rates on nuclei and implications for stellar core collapse.

Supernova simulations to date have assumed that during core collapse electron captures occur dominantly on free protons, while captures on heavy nuclei are Pauli blocked and are ignored. We have calculated rates for electron capture on nuclei with mass numbers A=65-112 for the temperatures and densities appropriate for core collapse. We find that these rates are large enough so that, in contrast to previous assumptions, electron capture on nuclei dominates over capture on free protons.

Strength of the 18F(p,alpha)15O resonance at Ec.m. = 330 keV.

Production of the radioisotope 18F in novae is severely constrained by the rate of the 18F(p,alpha)15O reaction. A resonance at E(c.m.

Simulation of the spherically symmetric stellar core collapse, bounce, and postbounce evolution of a star of 13 solar masses with boltzmann neutrino transport, and its implications for the supernova mechanism.

With exact three-flavor Boltzmann neutrino transport, we simulate the stellar core collapse, bounce, and postbounce evolution of a 13M star in spherical symmetry, the Newtonian limit, without invoking convection. In the absence of convection, prior spherically symmetric models, which implemented approximations to Boltzmann transport, failed to produce explosions. We consider exact transport to determine if these failures were due to the transport approximations made and to answer remaining fundamental questions in supernova theory.

Management of AIDS-related pneumothorax.

Background: Pneumothorax (PTX) occurs in 5% of patients with acquired immunodeficiency syndrome (AIDS) infected with Pneumocystis carinii pneumonia, and up to 50% of those will die during hospitalization. The treatment strategies for managing AIDS-related PTXs are often complex and ineffective at treating the PTX, and they can prolong hospitalization.

Methods: We reviewed our experience with 36 male patients with AIDS treated for 44 PTXs over a 2.

Repair of tracheogastric fistula after cervical exenteration.

A case of tracheogastric fistula after laryngopharyngoesophagectomy for cervical esophageal cancer is described. The surgical management of the tracheogastric fistula is detailed and accompanied by a pertinent review of the literature. The one-stage repair in this report can provide an effective palliation or definitive treatment for this debilitating and unusual complication.

Calcification as a sign of sarcomatous degeneration of malignant pleural mesotheliomas: a new CT finding.

We present two cases demonstrating, on CT examination, heavily calcified mass lesions associated with malignant pleural mesothelioma in workers occupationally exposed to asbestos. These masses proved to be osteogenic sarcomatous degeneration within mesotheliomas. The observation of dense calcification within a pleural mass should raise a suspicion of osteosarcomatous degeneration if it is seen in conjunction with other classic signs of malignant pleural mesothelioma.

Role of open lung biopsy in diagnosing pulmonary complications of AIDS.

Over a 4-year period, 25 patients with pulmonary complications of acquired immunodeficiency syndrome underwent open lung biopsy for diagnosis. Results of the biopsy led to a change in therapy in 15, and of this group, 8 patients improved clinically and were discharged. We believe that a select group of acquired immunodeficiency syndrome patients with pulmonary disease will benefit from open lung biopsy.

Solitary pulmonary nodule. What should be included in the workup?

Rapid, thorough diagnostic workup of patients with solitary pulmonary nodules is imperative. The optimal management for these patients is exploratory thoracotomy for biopsy and appropriate resection. Preliminary fiberoptic bronchoscopy and transthoracic needle aspiration do not rule out malignant tumors if negative and add only unnecessary complexity, delay, expense, and risk to the patient's management.

Malignant pleural effusion treated by tetracycline sclerotherapy. A comparison of single vs repeated instillation.

Fifty patients with malignant pleural effusion were randomized to receive one or two doses of tetracycline sclerotherapy. We found that a single sclerotherapy treatment with tetracycline at a dose of 20 mg/kg was as effective as two sclerotherapy treatments and provided symptomatic relief in 46 of the 50 patients.

Reexpansion pulmonary edema.

Unilateral reexpansion pulmonary edema (RPE) is a rare complication of the treatment of lung collapse secondary to pneumothorax, pleural effusion, or atelectasis. Although RPE generally is believed to occur only when a chronically collapsed lung is rapidly reexpanded by evacuation of large amounts of air or fluid, in this review 15 of 47 cases of RPE available for assessment occurred when the pulmonary collapse was of short duration or when the lung was reexpanded without suction. The pathogenesis of RPE is unknown and is probably multifactorial.

Active specific immunotherapy with an autologous tumor cell vaccine in patients with resected non-small cell lung cancer.

Eighteen postoperative patients with non-small cell lung cancer were actively immunized with a vaccine that included autologous cryopreserved irradiated tumor cells admixed with bacillus Calmette-Guerin. Patients received three weekly intradermal immunizations beginning 1-3 months after surgery (15 patients) or after completion of postoperative radiotherapy (3 patients). There was marked heterogeneity in the relative proportion of tumor cells versus host infiltrating cells within individual vaccines (range of percent tumor cells 7-75%).

Visceral pleural thickening in asbestos exposure: the occurrence and implications of thickened interlobar fissures.

We evaluated fissural (ie, visceral pleural) thickening on radiographs in two asbestos-exposed study populations and a control group. Asbestos workers had an incidence of fissural thickening of 54.5% compared with 16.

Toluidine blue staining of the esophagus. A useful adjunct in the panendoscopic evaluation of patients with squamous cell carcinoma of the head and neck.

Carcinoma of the esophagus has a much higher incidence among patients with squamous cell carcinoma of the head and neck than among the population at large. Esophageal cancer has a low cure rate, and the possibility for increased survival can be enhanced primarily through early detection. Toluidine blue has proved to be effective in demonstrating early malignant lesions that would not be detectable otherwise.

Lytic therapy in the treatment of axillary and subclavian vein thrombosis.

The importance of individualized treatment of patients with primary and secondary axillary-subclavian vein thrombosis is described with special emphasis on the use of thrombolytic therapy. Nine patients were treated with streptokinase or urokinase. Balloon dilation of the axillary or subclavian vein and first rib resection were also selectively used.

Azygos lymph node enlargement as initial manifestation of underlying disease.

Azygos lymph node enlargement is usually an indication of advanced bronchogenic carcinoma, although it may occur in benign pulmonary disease. Often it is found in conjunction with enlargement of hilar and other mediastinal lymph nodes. Isolated azygos lymph node enlargement is unusual and demands tissue diagnosis.