[en] To determine the efficacy of radionuclide therapy using Re-188 and P-32 patches for treatment of keloids. Twenty-four patients with 61 keloid lesions who received radionuclide patch therapy were included in the study. Shape and surface area of the lesions was calculated. Patches conforming to the shape and size of the individual lesions were applied superficially so as to deliver 50 Gy/cm² of surface radiation dose. Randomized patients for treatment with P-32 and Re-188 were matched for age, sex, number and extent of lesions into two groups (P > 0.05). Seventeen, 14, and 10 lesions demonstrated a reduction in lesion size of 50%-80%, 80%-99%, and complete disappearance, respectively. There was a >50% decrease in lesion size in 41 (67%) lesions. Sixteen (76%) lesions in P-32 group demonstrated decrease in lesion size of more than 50% as compared to 25 (62%) lesions in Re-188 group, the difference not being statistically significant (P > 0.5). Spectrum of radiation dermatitis ranging from pain itching, erythema, crusting, desquamation, and re-epithelialization was observed as side effects in patients. Radionuclide therapy using Re-188 and P-32 as radioactive skin patches is an effective and safe therapeutic option for the treatment of keloids. (author)

[en] Non-interferometric phase contrast effects have been shown to enhance material edges in neutron images. The achieved contrast enhancement in the image depends upon the neutron coherent scattering lengths of the materials present in the object and the degree of spatial coherence of the neutron beam. Spatial coherence of the beam is achieved using design-based spatial filters, a large L/d ratio (∼10,000) and low average neutron energy. Physically, a large L/d ratio is realized by a pinhole neutron source thereby significantly reducing the neutron beam intensity at the image plane. Thus, performance of such imaging exercises at low/medium intensity neutron sources is associated with additional design considerations that are not needed at high intensity neutron sources, where it has been demonstrated. In the present work, phase contrast neutron imaging was conducted using a suitably designed collimator at the 1-MWth PULSTAR reactor located at North Carolina State University (NCSU). Results of the imaging exercises that depict phase contrast edge enhancement are being presented along with the collimator design. Digital image plate detectors were used to capture images with a range of exposure times between 45 and 120 min.

[en] Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms which can arise from almost any location in the body. Diagnosing them pre-operatively is difficult as they mimic features of other hepatic neoplasms including hepatocellular carcinoma (HCC), fibrolamellar HCC, and focal nodular hyperplasia (FNH) among others. The unique feature of these tumors is the coexpression of muscle and melanocytic markers. These are identified immunohistochemically by the expression of Human Melanin Black-45 (HMB-45), Melan-A and Smooth Muscle Antigen (SMA) which are seen in the majority of tumors. The liver is uncommonly associated with a PEComa and the approach to a patient with hepatic PEComa is not well described. There is no consensus regarding the neo-adjuvant/adjuvant therapy in these patients. The natural history of this condition is not well documented making it an unpredictable disease. Here we have discussed a case and reviewed the literature concerning these rare tumors.

[en] A neutron imaging facility is located on beam-tube no. 5 of the 1-MW PULSTAR reactor at North Carolina State University. An investigation of high resolution imaging using the coded source imaging technique has been initiated at the facility. Coded imaging uses a mosaic of pinholes to encode an aperture, thus generating an encoded image of the object at the detector. To reconstruct the image data received by the detector, the corresponding decoding patterns are used. The optimized design of coded mask is critical for the performance of this technique and will depend on the characteristics of the imaging beam. In this work, a 34x38 uniformly redundant array (URA) coded aperture system is studied for application at the PULSTAR reactor neutron imaging facility. The URA pattern was fabricated on a 500 μm gadolinium sheet. Simulations and experiments with a pinhole object have been conducted using the Gd URA and the optimized beam line.

[en] Normalized indentation works, referred to as the total and elastic energy constants, have been shown to be effective in the representation and analysis of experimental load–displacement data. However, their physical meaning, influencing factors, variation range and relationships with other nanomechanical quantities are not precisely known. In this study, the load–displacement data obtained as a result of simulations of elastic and elasto-plastic indentations are extensively analysed to enhance our understanding concerning these two energy-based parameters. It has been shown that while the total energy constant describes the state of an indenter tip and the type of contact regime, the elastic energy constant characterizes the response of a material to indentation. In addition, their applications in the evaluation of key nanomechanical quantities such as the indenter tip radius, the nominal hardness and the contact depth are also discussed. (paper)