1,721,173 research outputs found
An efficient NAND flash file system for flash memory storage
No full textIn this paper, we present an efficient flash file system for flash memory storage. Flash memory, especially NAND flash memory, has become a major method for data storage. Currently, a block level translation interface is required between an existing file system and flash memory chips due to its physical characteristics. However, the approach of existing file systems on top of the emulating block interface has many restrictions and is, thus, inefficient because existing file systems are designed for disk-based storage systems. The flash file system proposed in this paper is designed for NAND flash memory storage while considering the existing file system characteristics. Our target performance metrics are the system booting time and garbage collection overheads, which are important issues in flash memory. In our experiments, the proposed flash file system outperformed other flash file systems both in booting time and garbage collection overheads
(Poster) Quantitative analysis of carrier escape and recombination efficiency in GaN-based blue light-emitting diodes
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A new raid-disk placement method for interactive media server with an accurate bit count control
No full textIn this paper, we propose a RAID-disk placement algorithm of coded video data and an efficient disk prefetching method to increase the number of clients who can be serviced interactive operations in the media server. Our placement policy is incorporated with a special bit count control method that is based on repeated tuning of quantization parameters to adjust the actual bit count to the target bit count. The encoder using this method can generate coded frames whose sizes are synchronized with the RAID stripe size, so that when various fast-forward levels are accessed we can reduce the seek and rotational latency and enhance the disk throughput
Analysis of an Aperture-Coupled Microstrip Patch Antenna having and Asymmetric Cross Slot
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Angiogenic and Immunomodulatory effects of embryonic stem cell derived mesenchymal stem cells in a murine model of ischemic hindlimb
No full textIn critical limb-threatening ischemia (CLTI), failed revascularization and pharmacotherapy substantially increase amputation and mortality risks. Mesenchymal stem cells (MSCs) are a promising therapeutic option for CLTI. This study evaluated the therapeutic effects of embryonic stem cell-derived MSCs (E-MSCs) on inflammation and angiogenesis under ischemic conditions across different E-MSC doses. Hindlimb ischemia was induced in 85 BALB/c nude mice by cauterizing the femoral and branched arteries. The mice were divided into five groups: non-ischemia (G1); saline-treated ischemia (G2); and ischemia treated with E-MSCs at low, medium, and high doses (G3-G5). Therapeutic effects were assessed using the rotarod test, blood perfusion ratio, and histological and cytokine analyses. G1 exhibited normal blood perfusion and motor function, whereas E-MSC-treated groups (G3-G5) demonstrated improved perfusion compared to G2. Although the medium-dose group (G4) showed numerically greater recovery, differences between G3, G4, and G5 were not statistically significant, suggesting no dose-response. All E-MSC-treated groups exhibited reduced inflammation and increases in motor function and angiogenic factors. Histological analysis revealed enhanced myofiber regeneration, reduced inflammatory infiltration, and diminished collagen deposition in the ischemic muscle of G3-G5. These changes were observed across all dose groups without significant dose-dependent differences. These results suggest E-MSCs enhance blood perfusion and modulate inflammation and angiogenesis in ischemic limbs, regardless of dose. These findings support the therapeutic potential of E-MSCs in CLTI, although further investigation is needed to optimize dosing and elucidate the mechanisms involved
Predictors of unplanned 30-day readmissions after coronary artery bypass graft: A systematic review and meta-analysis of cohort studies
No full textAims: Coronary artery bypass graft (CABG) is one of the most performed cardiac surgery globally. CABG is known to have a high rate of short-term readmissions. The 30-day unplanned readmission rate as a quality measure is associated with adverse health outcomes. This study aimed to identify and synthesize the perioperative risk factors for 30-day unplanned readmission after CABG. Methods and results: We systematically searched seven databases and reviewed studies to identify all eligible English articles published from 1 October 1999 to 30 September 2019. Random-effect models were employed to perform pooled analyses. Odds ratio and 95% confidence interval were used to estimate the risk factors for 30-day unplanned readmission. The 30-day hospital readmission rates after CABG ranged from 9.2% to 18.9% in 14 cohort studies. Among preoperative characteristics, older adults, female, weight loss, high serum creatinine, anticoagulant use or dialysis, and comorbidities were found to be statistically significant. Postoperative complications, prolonged length of hospital stay, and mechanical ventilation were revealed as the postoperative risk factors for 30-day unplanned readmission. However, intraoperative risk factors were not found to be significant in this review. Conclusion: Our findings emphasize the importance of a comprehensive assessment during the perioperative period of CABG. Healthcare professionals can perform a readmission risk stratification and develop strategies to reduce readmission rates after CABG using the risk factors identified in this review. Future studies with prospective cohort samples are needed to identify the personal or psychosocial factors influencing readmission after CABG, including perioperative risk factors
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