161 research outputs found

    High-efficiency Bidirectional Buck-Boost Converter for Residential Energy Storage System

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    This paper proposes a bidirectional dc-dc converter for residential micro-grid applications. The proposed converter can operate over an input voltage range that overlaps the output voltage range. This converter uses two snubber capacitors to reduce the switch turn-off losses, a dc-blocking capacitor to reduce the input/output filter size, and a 1:1 transformer to reduce core loss. The windings of the transformer are connected in parallel and in reverse-coupled configuration to suppress magnetic flux swing in the core. Zero-voltage turn-on of the switch is achieved by operating the converter in discontinuous conduction mode. The experimental converter was designed to operate at a switching frequency of 40-210 kHz, an input voltage of 48 V, an output voltage of 36-60 V, and an output power of 50-500 W. The power conversion efficiency for boost conversion to 60 V was >= 98.3% in the entire power range. The efficiency for buck conversion to 36 V was >= 98.4% in the entire power range. The output voltage ripple at full load was <3.59 V-p.p for boost conversion (60 V) and 1.35 V-p.p for buck conversion (36 V) with the reduced input/output filter. The experimental results indicate that the proposed converter is well-suited to smart-grid energy storage systems that require high efficiency, small size, and overlapping input and output voltage ranges.11Ysciescopu

    Clinical outcomes for T1-2N0-1 oral tongue cancer patients underwent surgery with and without postoperative radiotherapy

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    BACKGROUND: The aim of this study was to assess the results of curative surgery with and without radiotherapy in patients with T1-2N0-1 oral tongue squamous cell carcinoma (OSCC) and to evaluate survival and prognostic factors. METHODS: Retrospective analysis of 86 patients with T1-2N0-1 OSCC who received surgery between January 2000 and December 2006. Fourteen patients (16.3%) received postoperative radiotherapy (PORT). Patient characteristics, tumor characteristics, treatment modality, failure patterns, and survival rates were analyzed. RESULTS: The median follow-up was 45 months. The five-year overall survival (OS) and disease-free survival (DFS) rates were 80.8% and 80.2%, respectively. Higher tumor grade and invasion depth > or = 0.5 cm were the significant prognostic factors affecting five-year OS and DFS (OS rate; 65% vs. 91%, p = 0.001 for grade; 66% vs. 92%, p = 0.01 for invasion depth: DFS rate; 69% vs. 88%, p = 0.005 for grade; 66% vs. 92%, p = 0.013 for invasion depth). In the risk group, there was no local failure in patients with postoperative radiotherapy. CONCLUSIONS: In T1-2N0-1 OSCC, factors that affected prognosis after primary surgery were higher tumor grade and deep invasion depth over 0.5 cm. Postoperative radiotherapy should be considered in early oral tongue cancer patients with these high-risk pathologic featuresope

    Transition from Pemphigus Foliaceus to Pemphigus Vulgaris: Case Report with Literature Review

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    The transition between the main subtypes of pemphigus, pemphigus vulgaris (PV), and pemphigus foliaceus (PF) has rarely been reported. Moreover, the development of PV in a patient with PF is much more unusual than that of PF in a patient with PV. We report a 48-year-old man who presented with cutaneous lesions showing the typical clinical and histological features of PF. Five years later, his skin lesions became extensive and he developed oral erosions. His condition did not respond well to steroids and azathioprine. Histological examination of a vesicle disclosed suprabasal acantholysis in contrast to the subcorneal acantholysis discovered upon initial histological evaluation. Indirect immunofluorescence revealed IgG antikeratinocyte cell surface antibodies at a titer of 1:640. The titer was 1:160 at initial diagnosis. Upon immunoblotting, the patient's serum reacted with 130 kiloDalton (kDa) and 160 kDa proteins, suggesting desmoglein (Dsg) 3 and 1, respectively. We herein report an unusual case of PV that developed from PF during the disease's flare-up

    Hypofractionated High-Dose Intensity-Modulated Radiotherapy (60 Gy at 2.5 Gy per Fraction) for Recurrent Renal Cell Carcinoma: A Case Report

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    A patient with renal cell carcinoma (RCC) developed synchronous bone metastasis with metachronous relapses to the bone and renal fossa. The primary lesion was initially removed surgically, and the metastatic bone lesions and locally recurrent tumours were treated by a high-fractional dose and high-total-dose intensity-modulated radiotherapy (IMRT, 60 Gy at 2.5 Gy per fraction) without significant side effects. All the grossly relapsed tumors underwent complete remission (CR) within a short time after IMRT. To date, CR has been maintained for more than two years. This case study reports the successful treatment of radioresistant RCC using a new scheme that involves a fractionation regimen with a high precision radiotherapy

    Successful Retrieval of a Fractured and Entrapped 0.035-Inch Terumo Wire in the Femoral Artery Using Biopsy Forceps

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    A 0.035-inch guide wire fracture and entrapment in a peripheral artery is a very rare complication, but when it does occur it may lead to life-threatening complications, such as perforation, thrombus formation, embolization, and subsequent limb ischemia. We describe our experience of successfully retrieving a fractured 0.035-inch Terumo guide wire in the external iliac artery using a biopsy forcep

    Positional Reproducibility and Effects of a Rectal Balloon in Prostate Cancer Radiotherapy

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    Despite the increasing use of the rectal balloon in prostate cancer radiotherapy, many issues still remain to be verified objectively including its positional reproducibility and relevance to treatment morbidity. We have developed a custom rectal balloon that has a scale indicating the depth of insertion and dilates symmetrically ensuring positional reproducibility. Fifty patients with prostate cancer treated by definitive 3D-conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) with rectal balloon were analyzed. Each of first five patients undergone computed tomography (CT) three times with a rectal balloon. The positional reproducibility was tested by Intraclass Correlation Coefficient (ICC) from the CT-to-CT fusion images. Planning variables and clinical acute toxicities were compared between when or not applying balloon. An ICC of greater than 0.9 in all directions revealed an excellent reproducibility of the balloon. Rectal balloon improved considerably the mean dose and V45Gy-V65Gy in plan comparison, and especially in 3D-CRT the rectal volume exposed to more than 60 Gy dropped from 41.3% to 19.5%. Clinically, the balloon lowered acute toxicity, which was lowest when both the balloon and IMRT were applied simultaneously. The rectal balloon carries excellent reproducibility and reduces acute toxicity in 3D-CRT and IMRT for prostate cancer

    Relationship Between Sarcopenia and Prognosis in Patient With Concurrent Chemo-Radiation Therapy for Esophageal Cancer

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    Background: Sarcopenia, defined as skeletal muscle loss, has been known as a poor prognosis factor in various malignant diseases The aim of this study is to investigate the effect of sarcopenia on prognosis in patients with esophageal cancer who received concurrent chemo- and radiotherapy (CCRT).Methods: We retrospectively collected clinical data of 287 patients with esophageal cancer who were treated by definite CCRT at Gangnam Severance and Severance hospital from August 2005 to December 2014. The cross-sectional area of muscle at the level of the third lumbar vertebra was measured using pre- and post-CCRT computed tomography images. Sarcopenia was defined as skeletal muscle index &lt;49 cm2/m2 for men and of &lt;31 cm2/m2 for women by Korean-specific cutoffs. Overall survival (OS) and progression free survival (PFS) were analyzed according to sarcopenia.Results: Sarcopenia identified before CCRT did not affect OS and PFS. However, patients with post-CCRT sarcopenia showed shorter OS and PFS than patients without it (median OS: 73 months vs. 28 months; median PFS: 34 months vs. 25 months, respectively). Post-CCRT sarcopenia was an independent prognostic factor of poor OS (hazards ratio: 1.697; 95% confidence interval: 1.036–2.780; P = 0.036). In multivariate analysis, male sex (P = 0.004) and presence of CCRT-related complications, such as esophagitis or general weakness were significantly associated with post-CCRT sarcopenia (P = 0.016).Conclusions: Sarcopenia after CCRT can be a useful predictor for long-term prognosis in patients with esophageal cancer. To control CCRT-related complications may be important to prevent skeletal muscle loss during CCRT
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