Relationships between study habits, burnout, and general surgery resident performance on the American Board of Surgery In-Training Examination.

Background: The American Board of Surgery In-Training Examination (ABSITE) is used by programs to evaluate the knowledge and readiness of trainees to sit for the general surgery qualifying examination. It is often used as a tool for resident promotion and may be used by fellowship programs to evaluate candidates. Burnout has been associated with job performance and satisfaction; however, its presence and effects on surgical trainees' performance are not well studied.

Effects of thermal annealing on the structural and optical properties of carbon-implanted SiO2.

Amorphous carbon (a-C) nanoclusters were synthesized by the implantation of carbon ions (C-) into thermally grown silicon dioxide film (-500 nm thick) on a Si (100) wafer and processed by high temperature thermal annealing. The carbon ions were implanted with an energy of 70 keV at a fluence of 5 x 10(17) atoms/cm2. The implanted samples were annealed at 1100 degrees C for different time periods in a gas mixture of 96% Ar+4% H2.

Constitutive cholesterol-dependent endocytosis of melanocortin-4 receptor (MC4R) is essential to maintain receptor responsiveness to α-melanocyte-stimulating hormone (α-MSH).

Melanocortin-4 receptor (MC4R) is a G-protein-coupled receptor expressed in the hypothalamus where it controls feeding behavior. MC4R cycles constitutively and is internalized at the same rate in the presence or absence of stimulation by the agonist, melanocyte-stimulating hormone (α-MSH). This is different from other G-protein-coupled receptors, such as β(2)-adrenergic receptor (β(2)AR), which internalizes more rapidly in response to agonist stimulation.

Narrow band UV emission from direct bandgap Si nanoclusters embedded in bulk Si.

We report on the formation of UV emitting Si nanoclusters (NCs) in Si, using a two stage Au implantation technique. These Si NCs, with an average size of 2 nm, show photoluminescence at room temperature, over a narrow band of about 100 meV with a peak of emission near 3.3 eV.

Spontaneous coordinated activity in cultured networks: analysis of multiple ignition sites, primary circuits, and burst phase delay distributions.

All higher order central nervous systems exhibit spontaneous neural activity, though the purpose and mechanistic origin of such activity remains poorly understood. We quantitatively analyzed the ignition and spread of collective spontaneous electrophysiological activity in networks of cultured cortical neurons growing on microelectrode arrays. Leader neurons, which form a mono-synaptically connected primary circuit, and initiate a majority of network bursts were found to be a small subset of recorded neurons.

Ion beam analyses of carbon nanotubes.

The utility of ion beam analysis (IBA) techniques to quantitatively determine impurities in carbon nanotubes (CNTs) over a wide range of atomic numbers is demonstrated. Such techniques have not previously been used to monitor impurities and their effects in this unique material. Despite the difficulty in mounting the samples (which generally are formed into a powdery aggregate rather in a thin film), it is shown that reliable and accurate measurements of impurity concentrations can be achieved.

Monte carlo simulations and experimental studies of yttrium-90 production using a 33 MeV linac.

The purpose of this research is the investigation of the 90Zr(n,p)90Y reaction as an alternative method to the traditional fission product based on the 90Sr/90Y generator. The fast neutrons necessary to activate 90Zr are generated through (p,xn) reactions during 33 MeV proton irradiation of natural tungsten or other targets. Since 90Y is a pure beta emitter, the gamma-rays from the 90Zr(n,2n)59Zr reaction were used to quantify the neutron flux incident on the 90Zr sample.

The target sign: a CT finding in tumors of the corpus callosum.

An unusual computed tomography finding, the "target sign," is demonstrated in a patient with a corpus callosum tumor mass extending to the right lateral ventricle. The central low attenuation of the "target" is produced by the isolated part of the dilated lateral ventricle surrounded by tumor tissue, the dense area of the "target." The diagnosis of the tumor of the corpus callosum and the explanation of the "target sign" was made by polytome pneumoencephalography.