2,881 research outputs found

    A Logical Model and Data Placement Strategies for MEMS Storage Devices

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    MEMS storage devices are new non-volatile secondary storages that have outstanding advantages over magnetic disks. MEMS storage devices, however, are much different from magnetic disks in the structure and access characteristics. They have thousands of heads called probe tips and provide the following two major access facilities: (1) flexibility: freely selecting a set of probe tips for accessing data, (2) parallelism: simultaneously reading and writing data with the set of probe tips selected. Due to these characteristics, it is nontrivial to find data placements that fully utilize the capability of MEMS storage devices. In this paper, we propose a simple logical model called the Region-Sector (RS) model that abstracts major characteristics affecting data retrieval performance, such as flexibility and parallelism, from the physical MEMS storage model. We also suggest heuristic data placement strategies based on the RS model and derive new data placements for relational data and two-dimensional spatial data by using those strategies. Experimental results show that the proposed data placements improve the data retrieval performance by up to 4.0 times for relational data and by up to 4.8 times for two-dimensional spatial data of approximately 320 Mbytes compared with those of existing data placements. Further, these improvements are expected to be more marked as the database size grows.Comment: 37 page

    The Glymphatic System in Diabetes-Induced Dementia

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    The glymphatic system has emerged as an important player in central nervous system (CNS) diseases, by regulating the vasculature impairment, effectively controlling the clearance of toxic peptides, modulating activity of astrocytes, and being involved in the circulation of neurotransmitters in the brain. Recently, several studies have indicated decreased activity of the glymphatic pathway under diabetes conditions such as in insulin resistance and hyperglycemia. Furthermore, diabetes leads to the disruption of the blood-brain barrier and decrease of apolipoprotein E (APOE) expression and the secretion of norepinephrine in the brain, involving the impairment of the glymphatic pathway and ultimately resulting in cognitive decline. Considering the increased prevalence of diabetes-induced dementia worldwide, the relationship between the glymphatic pathway and diabetes-induced dementia should be investigated and the mechanisms underlying their relationship should be discussed to promote the development of an effective therapeutic approach in the near future. Here, we have reviewed recent evidence for the relationship between glymphatic pathway dysfunction and diabetes. We highlight that the enhancement of the glymphatic system function during sleep may be beneficial to the attenuation of neuropathology in diabetes-induced dementia. Moreover, we suggest that improving glymphatic system activity may be a potential therapeutic strategy for the prevention of diabetes-induced dementia

    Effects of 12 weeks nutrition education on nutritional status in hemodialysis patients

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    Protein-energy malnutrition is present in a large proportion of patients with end stage renal disease and, is a strong risk factor for mortality in these patients. This study was aimed to evaluate the effectiveness of 12-weeks nutrition education during the hemodialysis session for the improvement of nutritional status. From the June 2011 to the September 2011, patients who were on regular hemodialysis in Pusan National University Hospital were enrolled in this study. In education group, intensive nutrition education was performed by the hemodialysis nurse, for fifty to sixty minutes during the hemodialysis session, once a week. Curriculum for renal nutrition includes regular taking of their medication, intake of moderate amount of protein and sufficient calories, reduction of water, salt, potassium and phosphate intake. Otherwise, any education program was not performed in patients of control group. Nutrition status was assessed by the subjective global assessment (SGA),body mass index (BMI), triceps skinfold thickness (TSF), arm muscle area(AMC) and laboratory markers such as serum albumin, serum blood urea nitrogen(BUN) and hemoglobin(Hb) level before and after the education. Effect of nutrition education was analyzed using ANCOVA test. A total of 49 patients were enrolled in this study and nutrition education was provided to 25 hemodialysis patients. Their mean age was 57.20±15.49 in education group and 55.13±14.42 in control groupand male was 56.0% in education group and 50.0% in control group and, other baseline characteristics were not significantly different between two groups. After the 12-week education, significant improvement was found in SGA, serum albumin, BUN and Hb level. SGA score was improved from 6.36±0.99 to 6.72±0.61 in education group, compared to control group(6.38±0.88 to 6.42±0.88, p=0.029 ). Improvement of serum albumin level, BUN and Hb was as follows: serum albumin(4.23±0.28 to 4.30±0.25 in education group, 4.28±0.39 to 4.13±0.34 in control group, p=0.040), serum Hb(10.45±1.49 to 11.13±1.74 in education group, 10.51±1.12 to 10.04±1.02 in control group, P=0.004), serum BUN(66.52±18.76 to 70.94±17.26 in education group, 59.50±13.61 to 58.68±13.88 in control group, p=0.032). 12 week nutrition education during the hemodialysis session by hemodialysis nurse was effectiv

    How Cereal Grass Shoots Perceive And Respond To Gravity

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141646/1/ajb208758.pd

    New Tubulocentric Insights for Diabetic Nephropathy: From Pathophysiology to Treatment

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    The prevalence of diabetes is increasing worldwide, and one of the most important complications, diabetic nephropathy, constitutes a significant global health care and socioeconomic burden. Glomerular dysfunction is a major factor in the development and progression of diabetic nephropathy. However, emerging evidence suggests that tubular damage also plays an important role in the pathogenesis of diabetic nephropathy. This tubulocentric view shifts the focus markedly from glomeruli to proximal tubules, which might have an important role as a trigger or a driver in the early development and progression of diabetic nephropathy. Accordingly, numerous studies have focused on several different tubular damage markers that are clinically indicated as potential biomarkers for the early detection of diabetic nephropathy. Furthermore, these findings are relevant for identifying therapeutics for diabetic nephropathy that target the proximal tubules. This review outlines new tubulocentric insights into diabetic nephropathy, from pathophysiological mechanisms to diagnostic and therapeutic approaches

    Atomic layer coating of hafnium oxide on carbon nanotubes for high-performance field emitters

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    Carbon nanotubes coated with hafnium oxide exhibit excellent electron emission characteristics, including a low turn-on voltage, a high field enhancement factor, and exceptional current stability. Their enhanced emission performance was attributed to a decrease in the work function and an increase in the electron density of states at the carbon nanotube Fermi level closest to the conduction band minimum of hafnium oxide. In addition, the enhanced current stability was attributed to the ability of hafnium oxide to protect the carbon nanotubes against ions and free radicals created in the electron field emission process. (C) 2011 American Institute of Physics. [doi:10.1063/1.3650471]ArticleAPPLIED PHYSICS LETTERS. 99(15):153115 (2011)journal articl

    Multisensor Estimation Fusion of Nonlinear Cost Functions in Mixed Continuous-Discrete Stochastic Systems

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    We propose centralized and distributed fusion algorithms for estimation of nonlinear cost function (NCF) in multisensory mixed continuous-discrete stochastic systems. The NCF represents a nonlinear multivariate functional of state variables. For polynomial NCFs, we propose a closed-form estimation procedure based on recursive formulas for high-order moments for a multivariate normal distribution. In general case, the unscented transformation is used for calculation of nonlinear estimates of a cost functions. To fuse local state estimates, the mixed differential difference equations for error cross-covariance between local estimates are derived. The subsequent application of the proposed fusion estimators for a multisensory environment demonstrates their effectiveness
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