Large-Scale Monte Carlo Study of a Realistic Lattice Model for Ga_(1-x)Mn_xAs

The properties of Mn-doped GaAs are studied at several doping levels and hole compensations, using a real-space Hamiltonian on an fcc lattice that reproduces the valence bands of undoped GaAs. Large-scale Monte Carlo (MC) simulations on a Cray XT3 supercomputer, using up to a thousand nodes, were needed to make this effort possible. Our analysis considers both the spin-orbit interaction and the random distribution of the Mn ions. The hopping amplitudes are functions of the GaAs Luttinger parameters. At the coupling J~1.2eV deduced from photoemission experiments, the MC Curie temperature and the shape of the magnetization curves are in agreement with experimental results for annealed samples. Although there are sizable differences with mean-field predictions, the system is found to be closer to a hole-fluid regime than to localized carriers

Expression of Plakophilins (PKP1, PKP2, and PKP3) in Gastric Cancers

BACKGROUND: The importance of cell-cell junction proteins (including armadillo proteins) in tumor biology is known, but limited with regard to plakophilins. We explored the relationship between plakophilins (PKP1, PKP2, PKP3) to gastric cancer via immunohistochemical techniques. METHODS: We compared the immunohistochemistry of PKPs in 34 gastric adenocarcinomas and 20 normal gastric tissues. RESULTS: In gastric cancer, PKP1 expression was unchanged but PKP2 and PKP3 were significantly decreased as compared to normal controls. There was no observable clinical association with PKP1 or PKP2 expression; however, low PKP3 level and poor prognosis appeared to correlate with regards to node number and tumor stage. The mean disease-free survival (DFS) was 38 ± 3 months (range: 32 - 44) and mean overall survival (OS) 42 ± 4 months (range: 38 - 50). Decreased PKP2 appeared to negatively impact DFS. CONCLUSION: Decreased PKP2 and PKP3 may be early prognostic markers and loss of PKP3 expression during gastric carcinoma progression may indicate an invasive phenotype

A Title 40 Code of Federal Regulations Part 191 Evaluation of Buried Transuranic Waste at the Nevada Test Site -8210

ABSTRACT In 1986, 21 m 3 of transuranic (TRU) waste was inadvertently buried in a shallow land burial trench at the Area 5 Radioactive Waste Management Site on the Nevada Test Site (NTS). Th

A Title 40 Code of Federal Regulations Part 191 Evaluation of Buried Transuranic Waste at the Nevada Test Site

In 1986, 21 m{sup 3} of transuranic (TRU) waste was inadvertently buried in a shallow land burial trench at the Area 5 Radioactive Waste Management Site on the Nevada Test Site (NTS). The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office is considered five options for management of the buried TRU waste. One option is to leave the waste in-place if the disposal can meet the requirements of Title 40 Code of Federal Regulations (CFR) Part 191, 'Environmental Radiation Protection Standard for Management and Disposal of Spent Nuclear Fuel, High-Level, and Transuranic Radioactive Wastes'. This paper describes analyses that assess the likelihood that TRU waste in shallow land burial can meet the 40 CFR 191 standards for a geologic repository. The simulated probability of the cumulative release exceeding 1 and 10 times the 40 CFR 191.13 containment requirements is estimated to be 0.009 and less than 0.0001, respectively. The cumulative release is most sensitive to the number of groundwater withdrawal wells drilled through the disposal trench. The mean total effective dose equivalent for a member of the public is estimated to reach a maximum of 0.014 milliSievert (mSv) at 10,000 years, or approximately 10 percent of the 0.15 mSv 40 CFR 191.15 individual protection requirement. The dose is predominantly from inhalation of short-lived Rn-222 progeny in air produced by low-level waste disposed in the same trench. The transuranic radionuclide released in greatest amounts, Pu-239, contributes only 0.4 percent of the dose. The member of public dose is most sensitive to the U-234 inventory and the radon emanation coefficient. Reasonable assurance of compliance with the Subpart C groundwater protection standard is provided by site characterization data and hydrologic processes modeling which support a conclusion of no groundwater pathway within 10,000 years. Limited quantities of transuranic waste in a shallow land burial trench at the NTS can meet the requirements of 40 CFR 191

Probabilistic Performance Assessment of a Low-Level Radioactive Waste Disposal Site on the Nevada Test Site

The Area 5 Radioactive Waste Management Site on the Nevada Test Site has been disposing of low-level, mixed low-level, and transuranic radioactive waste since 1961. In 1988, the U.S. Department of Energy implemented performance objectives for low-level radioactive waste disposal site performance and required all site operators to prepare a performance assessment. Since then, an iterative performance assessment process has been implemented that consists of repeated cycles of site characterization, conceptual model formation/revision, and performance assessment modeling. At the end of each cycle uncertainty and sensitivity analysis are used to determine the need for revision and to identify topics requiring additional research and development. The performance assessment model is implemented in the GoldSim{reg_sign} probabilistic simulation platform. The current site conceptual model, based on site characterization data and process model results, assumes that there is no groundwater pathway under current climatic conditions and that radionuclide releases are predominately upward to the land surface. Radionuclides are released to the land surface by upward liquid advection/diffusion, gas diffusion, biointrusion, and inadvertent human intrusion. The model calculates dose for four members of public exposure scenarios and two intruder scenarios. The highest mean-dose, 0.04 mSv yr{sup -1}, is expected for a low-probability exposure scenario: establishment of a rural community at the site boundary at the end of institutional control. At the end of institutional control, doses are contributed primarily by {sup 3}H in agricultural products produced onsite. After approximately 300 years, the doses are contributed equally by {sup 99}Tc and {sup 210}Pb ingested in vegetables grown at the residence. Technetium is released to the surface by the coupled processes of liquid advection/diffusion occurring deep in the cover and plant uptake/animal burrowing occurring at shallower depths. Lead-210 is deposited in shallow cover soil by the radioactive decay of {sup 222}Rn diffusing in the gas phase. The highest mean dose for the more likely exposure scenario of transient recreational use of the site is 0.002 mSv yr{sup -1}. The transient visitor's dose is contributed predominantly by external irradiation from {sup 214}Pb and {sup 214}Bi, deposited in the cover by diffusion of {sup 222}Rn

Primary testicular lymphoma: a single centre experience

Aim: Primary testicular lymphoma (PTL) is an uncommon and aggressive form of extranodal non-Hodgkin’s lymphoma (NHL). We aimed to analyse the clinicopathological characteristics and outcomes of our PTL cases. Materials and Methods: A review was made of the medical records of 339 NHL patients who were treated in the Medical Oncology Department between January 2005 and December 2013. Results: 8 PTL patients were identified from the 339 NHL patients. The average age of the patients was 67.7 ± 7.9 years (range 53–79 years). The mean follow-up time was 24.8 months (range 7–98 months). Inguinal orchiectomy was performed as a diagnostic and initial therapy and all the patients underwent 4–6 cycles of chemoimmunotherapy consisting of cyclophosphamide, doxorubicin, vincristine and prednisone plus rituximab. 4 of 8 patients received intrathecal prophylactic chemotherapy and 6 of 8 patients continued contralateral testis irradiation. Relapse occured in only 1 patient in central nervous system after 6 months who had not received intrathecal prophylaxis. No contralateral testis relapse was observed. Conclusions: Primary testicular NHL is an uncommon entity and we evaluated 8 patients; with one relapse in central nervous system and no relapse in the contralateral testis. Key Words: primary testicular lymphoma, contralateral scrotal irradiation, intratechal chemotherapy

High optical efficiency of ZnO nanoparticles

We develop optically efficient photocatalytic ZnO nanoparticles that we chemically embed and well disperse into host PVAc thin films and experimentally demonstrate the highest optical efficiency of ∼70% in ZnO nanoparticle films, with increasing optical spectral efficiency as the excitation wavelength is swept from 370 nm to 290 nm. ©2007 Optical Society of America

Closure Strategy for a Waste Disposal Facility with Multiple Waste Types and Regulatory Drivers at the Nevada Test Site

The U.S. Department of Energy, National Security Administration Nevada Site Office (NNSA/NSO) is planning to close the 92-Acre Area of the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada Test Site (NTS), which is about 65 miles northwest of Las Vegas, Nevada. Closure planning for this facility must take into account the regulatory requirements for a diversity of waste streams, disposal and storage configurations, disposal history, and site conditions. This paper provides a brief background of the Area 5 RWMS, identifies key closure issues, and presents the closure strategy. Disposals have been made in 25 shallow excavated pits and trenches and 13 Greater Confinement Disposal (GCD) boreholes at the 92-Acre Area since 1961. The pits and trenches have been used to dispose unclassified low-level waste (LLW), low-level mixed waste (LLMW), and asbestiform waste, and to store classified low-level and low-level mixed materials. The GCD boreholes are intermediate-depth disposal units about 10 feet (ft) in diameter and 120 ft deep. Classified and unclassified high-specific activity LLW, transuranic (TRU), and mixed TRU are disposed in the GCD boreholes. TRU waste was also disposed inadvertently in trench T-04C. Except for three disposal units that are active, all pits and trenches are operationally covered with 8-ft thick alluvium. The 92-Acre Area also includes a Mixed Waste Disposal Unit (MWDU) operating under Resource Conservation and Recovery Act (RCRA) Interim Status, and an asbestiform waste unit operating under a state of Nevada Solid Waste Disposal Site Permit. A single final closure cover is envisioned over the 92-Acre Area. The cover is the evapotranspirative-type cover that has been successfully employed at the NTS. Closure, post-closure care, and monitoring must meet the requirements of the following regulations: U.S. Department of Energy Order 435.1, Title 40 Code of Federal Regulations (CFR) Part 191, Title 40 CFR Part 265, Nevada Administrative Code (NAC) 444.743, RCRA requirements as incorporated into NAC 444.8632, and the Federal Facility Agreement and Consent Order (FFACO). A grouping of waste disposal units according to waste type, location, and similarity in regulatory requirements identified six closure units: LLW Unit, Corrective Action Unit (CAU) 111 under FFACO, Asbestiform LLW Unit, Pit 3 MWDU, TRU GCD Borehole Unit, and TRU Trench Unit. The closure schedule of all units is tied to the closure schedule of the Pit 3 MWDU under RCRA

Closure Strategy for a Waste Disposal Facility with Multiple Waste Types and Regulatory Drivers at the Nevada Test Site

The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) plans to close the waste and classified material storage cells in the southeast quadrant of the Area 5 Radioactive Waste Management Site (RWMS), informally known as the '92-Acre Area', by 2011. The 25 shallow trenches and pits and the 13 Greater Confinement Disposal (GCD) borings contain various waste streams including low-level waste (LLW), low-level mixed waste (LLMW), transuranic (TRU), mixed transuranic (MTRU), and high specific activity LLW. The cells are managed under several regulatory and permit programs by the U.S. Department of Energy (DOE) and the Nevada Division of Environmental Protection (NDEP). Although the specific closure requirements for each cell vary, 37 closely spaced cells will be closed under a single integrated monolayer evapotranspirative (ET) final cover. One cell will be closed under a separate cover concurrently. The site setting and climate constrain transport pathways and are factors in the technical approach to closure and performance assessment. Successful implementation of the integrated closure plan requires excellent communication and coordination between NNSA/NSO and the regulators