Parallel Iterative Methods

In this paper we discuss the implementation of the ITPACK library [Kine 82] in the parallel (//)ELL-PACK environment [Holls 92] and report on its performance on the nCUBE II parallel machine. In this study we are concerned with the numerical solution of second order elliptic partial diITerential equations (PDEs) on rectangular regions with mixed boundary conditions using finite difference approximations. The parallelization methodology applied is based on the domain decomposition of discrete geometric data structures (grids) associated with the numerical solution of the PDE problem[Chri 91]. The implementa-tion of I jITPACK for boundary value problems defined on general 2·0 and 3-D domains for both finite element and difference methods is reported in [Kim 93]. The performance results obtained so far indicate almost optimal computational and space efficiency of the / /ITPACK modules

Ionizing radiation exposure and the development of soft-tissue sarcomas in atomic-bomb survivors

BACKGROUND: Very high levels of ionizing radiation exposure have been associated with the development of soft-tissue sarcoma. The effects of lower levels of ionizing radiation on sarcoma development are unknown. This study addressed the role of low to moderately high levels of ionizing radiation exposure in the development of soft-tissue sarcoma. METHODS: Based on the Life Span Study cohort of Japanese atomic-bomb survivors, 80,180 individuals were prospectively assessed for the development of primary soft-tissue sarcoma. Colon dose in gray (Gy), the excess relative risk, and the excess absolute rate per Gy absorbed ionizing radiation dose were assessed. Subject demographic, age-specific, and survival parameters were evaluated. RESULTS: One hundred and four soft-tissue sarcomas were identified (mean colon dose = 0.18 Gy), associated with a 39% five-year survival rate. Mean ages at the time of the bombings and sarcoma diagnosis were 26.8 and 63.6 years, respectively. A linear dose-response model with an excess relative risk of 1.01 per Gy (95% confidence interval [CI]: 0.13 to 2.46; p = 0.019) and an excess absolute risk per Gy of 4.3 per 100,000 persons per year (95% CI: 1.1 to 8.9; p = 0.001) were noted in the development of soft-tissue sarcoma. CONCLUSIONS: This is one of the largest and longest studies (fifty-six years from the time of exposure to the time of follow-up) to assess ionizing radiation effects on the development of soft-tissue sarcoma. This is the first study to suggest that lower levels of ionizing radiation may be associated with the development of soft-tissue sarcoma, with exposure of 1 Gy doubling the risk of soft-tissue sarcoma development (linear dose-response). The five-year survival rate of patients with soft-tissue sarcoma in this population was much lower than that reported elsewhere.published_or_final_versio

Inverted hysteresis and negative remanence in a homogeneous antiferromagnet

Magnetic remanence -- found in bar magnets or magnetic storage devices -- is probably the oldest and most ubiquitous phenomenon underpinning technological applications of magnetism. It is a macroscopic non-equilibrium phenomenon: a remanent magnetisation appears when a magnetic field is applied to an initially unmagnetised ferromagnet, and then taken away. Here, we present an inverted magnetic hysteresis loop in the pyrochlore compound Nd2Hf2O7: the remanent magnetisation points in a direction opposite to the applied field. This phenomenon is exquisitely tunable as a function of the protocol in field and temperature, and it is reproducible as in a quasi-equilibrium setting. We account for this phenomenon in considerable detail in terms of the properties of nonequilibrium population of domain walls which exhibit a magnetic moment between domains of an ordered antiferromagnetic state which itself has zero net magnetisation. Properties and (nonequilibrium) dynamics of topological defects play an important role in modern spintronics, and our study adds an instance where a uniform field couples selectively to domain walls rather than the bulk.Physic

Defining the clinical syndrome of lumbar spinal stenosis: an international Delphi study

INTRODUCTION: Lumbar spinal stenosis (LSS) is a poorly defined clinical syndrome. Criteria for defining a syndrome should be informed by the experience of expert clinicians. The objective of this Delphi study is to reach a consensus among international experts on which factors are most important in diagnosis of ...postprin

Classification of High Intensity Zones of the Lumbar Spine and Their Association with Other Spinal MRI Phenotypes: The Wakayama Spine Study

published_or_final_versio

Bone sarcomas in atomic bomb survivors of Hiroshima and Nagasaki

Abstract no. 1017PURPOSE/OBJECTIVE(S): Ionizing radiation‐induced bone sarcomas have traditionally been associated with exposure to high levels of ionizing radiation. The role of exposure to lower levels of ionizing radiation in the development of such lesions remains speculative. Also, the appropriate dose‐response model of radiation dose exposure to excess relative risk (ERR) in association with bone sarcomas is questionable. MATERIALS/METHODS: The data source of the longitudinal, population‐based Life Span Study (N=120,321) cohort of atomic bomb survivors of Hiroshima and Nagasaki was utilized to estimate the ERR per Gray (Gy) of ionizing radiation exposure in the development of bone sarcomas. Other factors regarding sarcoma demographics …postprin

Expression pattern of class I histone deacetylases in vulvar intraepithelial neoplasia and vulvar cancer: a tissue microarray study

BACKGROUND: Epigenetic regulation is an important mechanism leading to cancer initiation and promotion. Histone acetylation by histone deacetylases (HDACs) represents an important part of it. The development of HDAC inhibitors has identified the utility of HDACs as a therapeutic target. Little is known about the epigenetic regulation of vulvar intraepithelial neoplasia (VIN) and vulvar squamous cell cancer (VSCC). In this study, the expression of class I HDACs (HDAC 1, 2 and 3) was compared in a series of VIN and VSCC tissues. METHODS: A tissue micro array (TMA) with specimens from 106 patients with high-grade VIN and 59 patients with vulvar cancer was constructed. The expression of HDACs 1, 2 and 3 were analyzed with immunohistochemistry (IHC). The nuclear expression pattern was evaluated in terms of intensity and percentage of stained nuclei and was compared between vulvar preinvasive lesions and vulvar cancer. RESULTS: HDAC 2 expression was significantly higher in VIN than in VSCC (p < 0.001, Fisher's test). Also, 88.7% (n=94/106) of VIN samples and only 54.5% (n=31/57) of VSCC samples were scored at the maximum level. Conversely, HDAC 3 expression was significantly higher in VSCC (93%, 53/57) compared to VIN (73.6%, 78/106, p=0.003), whereas only a small difference in the expression of HDAC 1 was found between these two entities of vulvar neoplasia. CONCLUSIONS: These results suggest that epigenetic regulation plays a considerable role in the transformation of VIN to invasive vulvar neoplasia

Pitfalls and complications in the treatment of cervical spine fractures in patients with ankylosing spondylitis

Patients with ankylosing spondylitis are at significant risk for sustaining cervical spine injuries following trauma predisposed by kyphosis, stiffness and osteoporotic bone quality of the spine. The risk of sustaining neurological deficits in this patient population is higher than average. The present review article provides an outline on the specific injury patterns in the cervical spine, diagnostic algorithms and specific treatment modalities dictated by the underlying disease in patients with ankylosing spondylitis. An emphasis is placed on the risks and complication patterns in the treatment of these rare, but challenging injuries