444 research outputs found
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Comparison of the design and costs of induction linac drivers for inertial fusion using ions of differing mass
An induction linear accelerator that produces an energetic (5 to 20 GeV) beam of heavy (130 to 238 amu) ions is a prime candidate as a driver for inertial fusion. The required accelerator output parameters for an ion species can be determined from the target requirements for a given fusion energy yield. The cost and efficiency of various accelerator configurations to produce the required output parameters can be determined to aid in the selection of the lowest cost accelerator design option. In this study, we compare the cost of various accelerator configurations that will produce various target fields and fusion powers using cesium 133 ions with those using mercury 200 ions, and report extensively on some 600 MJ target yield results
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Comparison of the design and costs of induction linac drivers for inertial fusion using ions of mass 133 and 200
Optimized cost estimates for induction linac accelerators using mass 133 ions at a charge state of +2 producing inertial fusion target yields of 300, 600, and 1200 MJ are presented. The ions are injected into the accelerator at 3 MV, and accelerated to the required voltage appropriate to the desired target yield. A cost comparison of these drivers is made with drivers using mass 200, charge state +3 ions for several target yields and a fusion power of 3000 MW
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Cost/performance analysis of an induction linac driver system for inertial fusion
A linear induction accelerator that produces a beam of energetic (approx. =10 GeV) heavy (CAapprox.200) ions is a prime candidate as a driver for inertial fusion. Continuing developments in amorphous iron for use in accelerating modules represent a potentially large reduction in the driver cost and an increase in the driver efficiency. Additional insulator developments may also represent a potentially large reduction in the driver cost. The efficiency and cost of the induction linac system is discussed as a function of output energy and pulse repetition frequency for several beam charge states, numbers of beams and beam particle species. Accelerating modules and transport modules will be described. Large cost leverage items will be identified as a guide to future research activities and technology of development that can yield further substantial reductions in the accelerator system cost and improvement in the accelerator system efficiency. 13 refs., 2 figs
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Analysis of an induction linac driver system for inertial fusion
A linear induction accelerator that produces a beam of energetic (5 to 20 GeV) heavy (130 to 210 amu) ions is a prime candidate as a driver for inertial fusion. Continuing developments in sources for ions with charge state greater than unity allow a potentially large reduction in the driver cost and an increase in the driver efficiency. The use of high undepressed tunes (sigma/sub 0/ approx. = 85/sup 0/) and low depressed tunes (sigma approx. = 8.5/sup 0/) also contributes to a potentially large reduction in the driver cost. The efficiency and cost of the induction linac system are discussed as a function of output energy and pulse repetition frequency for several ion masses and charge states. The cost optimization code LIACEP, including accelerating module alternatives, transport modules, and scaling laws, is presented. Items with large cost-leverage are identified as a guide to future research activities and development of technology that can yield substantial reductions in the accelerator system cost and improvement in the accelerator system efficiency. Finally, a cost-effective strategy using heavy ion induction linacs in a development scenario for inertial fusion is presented. 34 refs., 6 figs., 7 tabs
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Heavy ion fusion system assessment: Final focus and transport model
This report discusses the trade-offs necessary to build an economical heavy ion fusion reactor. The principal concerns are the dynamics of the accelerated ion beam. 15 refs. (JDH
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Cost of induction linac driver for inertial fusion for various target yields
The cost of induction linac accelerators for inertial fusion using mass 200 ions at a charge state of +3 for target yields of 300, 600, and 1200 MJ is presented. The ions are injected into the accelerator at 3 MV, and accelerated to the required voltage appropriate to the desired target yield. A cost comparison of the low voltage portion of the accelerator (3 to 50 MV) is made between a system with 64 and one with 16 superconducting quadrupoles. The design of the low voltage portion which yields the minimum-cost accelerator designs for several target yields and a fusion power of 3000 MW is presented
Nasopharyngeal Myoepithelial Carcinoma Mimicking Nasopharyngeal Carcinoma
AbstractMyoepithelial carcinoma (malignant myoepithelioma) (MC) is a rare tumor, defined as a malignant salivary neoplasm composed almost exclusively of tumor cells with myoepithelial differentiation. It can arise in unusual location sites, such as the nasopharynx, and may be difficult to approach. Nasopharyngeal MC can sometimes present as a nasopharyngeal mass which may be mistaken for primary nasopharyngeal carcinoma (NPC). The treatment strategy for nasopharyngeal MC is different from NPC, and maximal surgical resection of the main lesion is still considered as the mainstay of therapy. Herein we present a 32-year-old man with a nasopharyngeal mass which was initially mistaken as NPC, and which was later confirmed as MC after a comprehensive review of the pathology
Multilocus Short Sequence Repeat Analysis of Mycobacterium avium subsp. paratuberculosis Isolates from Dairy Herds in Northeastern United States of a Longitudinal Study Indicates Low Shedders are Truly Infected
ABSTRACT The objectives of this study were to evaluate whether low shedders of Mycobacterium avium subsp. paratuberculosis (MAP) were pass-through animals or whether they were truly infected. We also evaluated whether these animals were possibly infected by the supershedders. The MAP isolates were obtained from a longitudinal study that involved three different herds in the northeastern US. The shedding levels of animals at each culturepositive occasion were determined. Selected isolates were collected from all animals that were culture-positive at the same time super-shedders were present in the herds and from super-shedders. Using a multilocus short sequence repeat (MLSSR) approach we found 15 different strains from a total of 142 isolates analyzed. The results indicated herd-specific infections; a clonal infection in herd C with 89% of animals sharing the same strain, different strains in herds A and B. In herd C, 100% and in herd A, 17 to 70% of cows shed the same strain as that of contemporary super-shedders at a given collection date. About 82% of available tissue samples were culture-positive indicating a true infection. Taken together the results of MAP strain-typing and shedding levels, we conclude that at least 50% of low shedders have same strain as that of a contemporary super-shedder. The results of this study indicate that very few cows had characteristics of a possible pass-through animal; many more cows were actively infected. The sharing of same strain of low shedders with the contemporary super-shedders suggests that low shedders may be infected as adults by the super-shedders
Homozygous familial hypercholesterolaemia: new insights and guidance for clinicians to improve detection and clinical management. A position paper from the Consensus Panel on Familial Hypercholesterolaemia of the European Atherosclerosis Society
AIMS:
Homozygous familial hypercholesterolaemia (HoFH) is a rare life-threatening condition characterized by markedly elevated circulating levels of low-density lipoprotein cholesterol (LDL-C) and accelerated, premature atherosclerotic cardiovascular disease (ACVD). Given recent insights into the heterogeneity of genetic defects and clinical phenotype of HoFH, and the availability of new therapeutic options, this Consensus Panel on Familial Hypercholesterolaemia of the European Atherosclerosis Society (EAS) critically reviewed available data with the aim of providing clinical guidance for the recognition and management of HoFH.
METHODS AND RESULTS:
Early diagnosis of HoFH and prompt initiation of diet and lipid-lowering therapy are critical. Genetic testing may provide a definitive diagnosis, but if unavailable, markedly elevated LDL-C levels together with cutaneous or tendon xanthomas before 10 years, or untreated elevated LDL-C levels consistent with heterozygous FH in both parents, are suggestive of HoFH. We recommend that patients with suspected HoFH are promptly referred to specialist centres for a comprehensive ACVD evaluation and clinical management. Lifestyle intervention and maximal statin therapy are the mainstays of treatment, ideally started in the first year of life or at an initial diagnosis, often with ezetimibe and other lipid-modifying therapy. As patients rarely achieve LDL-C targets, adjunctive lipoprotein apheresis is recommended where available, preferably started by age 5 and no later than 8 years. The number of therapeutic approaches has increased following approval of lomitapide and mipomersen for HoFH. Given the severity of ACVD, we recommend regular follow-up, including Doppler echocardiographic evaluation of the heart and aorta annually, stress testing and, if available, computed tomography coronary angiography every 5 years, or less if deemed necessary.
CONCLUSION:
This EAS Consensus Panel highlights the need for early identification of HoFH patients, prompt referral to specialized centres, and early initiation of appropriate treatment. These recommendations offer guidance for a wide spectrum of clinicians who are often the first to identify patients with suspected HoFH
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