Large-Scale Fabrication of Boron Nitride Nanotubes via a Facile Chemical Vapor Reaction Route and Their Cathodoluminescence Properties

Cylinder- and bamboo-shaped boron nitride nanotubes (BNNTs) have been synthesized in large scale via a facile chemical vapor reaction route using ammonia borane as a precursor. The structure and chemical composition of the as-synthesized BNNTs are extensively characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and selected-area electron diffraction. The cylinder-shaped BNNTs have an average diameter of about 100 nm and length of hundreds of microns, while the bamboo-shaped BNNTs are 100–500 nm in diameter with length up to tens of microns. The formation mechanism of the BNNTs has been explored on the basis of our experimental observations and a growth model has been proposed accordingly. Ultraviolet–visible and cathodoluminescence spectroscopic analyses are performed on the BNNTs. Strong ultraviolet emissions are detected on both morphologies of BNNTs. The band gap of the BNNTs are around 5.82 eV and nearly unaffected by tube morphology. There exist two intermediate bands in the band gap of BNNTs, which could be distinguishably assigned to structural defects and chemical impurities

Magnetic susceptibility anisotropy of myocardium imaged by cardiovascular magnetic resonance reflects the anisotropy of myocardial filament α-helix polypeptide bonds

BACKGROUND: A key component of evaluating myocardial tissue function is the assessment of myofiber organization and structure. Studies suggest that striated muscle fibers are magnetically anisotropic, which, if measurable in the heart, may provide a tool to assess myocardial microstructure and function. METHODS: To determine whether this weak anisotropy is observable and spatially quantifiable with cardiovascular magnetic resonance (CMR), both gradient-echo and diffusion-weighted data were collected from intact mouse heart specimens at 9.4 Tesla. Susceptibility anisotropy was experimentally calculated using a voxelwise analysis of myocardial tissue susceptibility as a function of myofiber angle. A myocardial tissue simulation was developed to evaluate the role of the known diamagnetic anisotropy of the peptide bond in the observed susceptibility contrast. RESULTS: The CMR data revealed that myocardial tissue fibers that were parallel and perpendicular to the magnetic field direction appeared relatively paramagnetic and diamagnetic, respectively. A linear relationship was found between the magnetic susceptibility of the myocardial tissue and the squared sine of the myofiber angle with respect to the field direction. The multi-filament model simulation yielded susceptibility anisotropy values that reflected those found in the experimental data, and were consistent that this anisotropy decreased as the echo time increased. CONCLUSIONS: Though other sources of susceptibility anisotropy in myocardium may exist, the arrangement of peptide bonds in the myofilaments is a significant, and likely the most dominant source of susceptibility anisotropy. This anisotropy can be further exploited to probe the integrity and organization of myofibers in both healthy and diseased heart tissue

IODIZED TALC PLEURODESIS FOR THE TREATMENT OF PLEURAL EFFUSIONS

This prospective study was designed to determine the efficacy of iodized talc pleurodesis in patients with pleural effusions. Thirty-four patients underwent this treatment (three bilaterally) between October 1, 1989, and March 31, 1991. All patients had to have complete or nearly complete lung reexpansion after tube thoracostomy with fluid drainage less than 100 ml in 24 hours. A slurry containing 5 gm of talc and 3 gm of thymol iodide was instilled into the pleural space through the chest tube. Chest tubes were removed after complete reexpansion and clearing of the effusions, usually in 3 to 5 days. The patients' ages ranged from 26 to 88 years (average 50 years). Eighteen patients had lung carcinoma, two had mesothelioma, and one each had carcinoma of the ovary, breast, or anorectum, multiple myeloma, schwannoma, or Hodgkin's lymphoma. Two patients had an unknown adenocarcinoma primary and five other patients had acquired immunodeficiency syndrome. One patient had congestive heart failure. Nineteen patients had left, 12 had right, and three had bilateral pleural effusions. The effusion was serosanguineous in 26 and serofibrinous in eight patients. Serial chest radiography showed complete response in all patients. The period of follow-up ranged from 1 to 21 (average 4.9) months, with no recurrences. Twenty-three patients have died during the follow-up period, and there was no sign that reaccumulated pleural effusion existed in any, despite clinical evidence of systemic tumor progression. These observations indicate that intrapleural instillation of a slurry of iodized talc is a safe, adequate, and effective treatment for control of neoplastic or benign pleural effusions

Grade 3 open tibial shaft fractures treated with a circular frame, functional outcome and systematic review of literature

We report on the surgical and functional outcome of 22 patients with Grade 3 open tibial fractures treated with circular frame. All cases united and there were no re-fractures or amputations. All patients were assessed at a minimum of 1-year post frame removal. Assessment included clinical examination, IOWA ankle and knee scores, Olerud and Molander ankle score and EuroQol EQ-5D. Clinical scores were either good or excellent in over half of the patients in all knee and ankle scores. There was a significant positive correlation between functional outcomes and the EQ-5D score. The EQ-5D mean health state visual analogue score was comparable to the general UK population despite patients scoring less than the average UK population in three of the five domains. 36% reported some difficulties in walking and 41% had problems with pain. 14% had difficulties with self-care and 46% had difficulties with their usual activities. 14% had problems with anxiety or depression. Systematic review of the literature suggests, in the management of open tibial fractures, circular frames provide equivalent or superior surgical outcomes in comparison with other techniques. Our study finds the application of a circular frame also results in a good functional outcome in the majority of cases