98 research outputs found

    Explosive fragmentation of thin ceramic tube using pulsed power

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    This study experimentally examined the explosive fragmentation of thin ceramic tubes using pulsed power. A thin ceramic tube was threaded on a thin copper wire, and high voltage was applied to the wire using a pulsed power generator. This melted the wire and the resulting vapor put pressure on the ceramic tube, causing it to fragment. We examined the statistical properties of the fragment mass distribution. The cumulative fragment mass distribution obeyed the double exponential or power-law with exponential decay. Both distributions agreed well with the experimental data. We also found that the weighted mean fragment mass was scaled by the multiplicity. This result was similar to impact fragmentation, except for the crossover point. Finally, we obtained universal scaling for fragmentation, which is applicable to both impact and explosive fragmentation.Comment: 5 pages, 6 figure

    Glass-phase coordination polymer displaying proton conductivity and guest-accessible porosity

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    We describe the preparation of the crystalline and glassy state of a coordination polymer displaying proton conduction and guest-accessible porosity. EXAFS and solid-state NMR analyses indicated that pyrophosphate and phosphate ions are the main proton transporters in the glass and that homogeneously distributed 5-chloro-1H-benzimidazole in the glass provide the porosity

    Pathologic stage I non–small cell lung cancer with high levels of preoperative serum carcinoembryonic antigen: Clinicopathologic characteristics and prognosis

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    ObjectiveSurgery alone remains the standard therapy for patients with stage I non–small cell lung cancer. Although the preoperative serum level of carcinoembryonic antigen has been shown to be an independent prognostic factor, it has not yet been included in the staging system and does not alter the treatment strategy, especially in the selection of patients for adjuvant chemotherapy.MethodsFrom 1986 to 2003, preoperative and postoperative serum carcinoembryonic antigen levels were measured in 455 patients with completely resected pathologic stage I non–small cell lung cancer. We compared the clinicopathologic characteristics and outcomes among patients who had preoperative serum carcinoembryonic antigen levels within the normal range (N group, n = 323), patients who had high carcinoembryonic antigen levels before surgery but normal levels after surgery (HN group, n = 112), and patients who had high carcinoembryonic antigen levels before and after surgery (HH group, n = 20).ResultsThe significant characteristics of the HN group included the male sex, greater age, smoking, squamous cell histology, T2 status, lymphatic invasion, vascular invasion, and pleural invasion. Adenocarcinomas in patients of the HN group were more likely to be moderately to poorly differentiated. The 5-year survivals in the HN and HH groups were significantly lower (56.2% and 43.1%, respectively) than those in the N group (85.9%). Multivariate analysis revealed that greater age, non-adenocarcinoma histology, pleural invasion, and the carcinoembryonic antigen in the HN and HH groups were independent prognostic factors.ConclusionPatients with resected pathologic stage I non–small cell lung cancer and high preoperative serum carcinoembryonic antigen levels are a subgroup with a distinctly poor prognosis who display smoking-related clinicopathologic characteristics

    GFAP-Negative Subcutaneous Sacrococcygeal Extraspinal Ependymoma

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    Ependymomas are slowly growing glial tumors derived from the ependymal cells and usually occur in the central nervous system (CNS). Ependymomas rarely occur outside of the CNS and they are called extraspinal ependymomas. In spite of their metastatic potential, extraspinal ependymomas can be misdiagnosed for other benign mass like pilonidal cysts. The diagnosis is confirmed by histopathology and most of the cases are known to show glial fibrillary acidic protein (GFAP), S-100 protein, and keratin (AE1AE3) immunoreactivity. Herein, we present a case of GFAP-negative ependymoma, which presented as asymptomatic subcutaneous tumor of the left buttock and was clinically misdiagnosed as epidermal cyst. Our case indicates that ependymomas cannot be ruled out by lack of GFAP immunoreactivity and an asymptomatic subcutaneous mass could be a malignant tumor like ependymomas, which requires careful examinations

    An Angiotensin II Type 1 Receptor Blocker Prevents Renal Injury via Inhibition of the Notch Pathway in Ins2 Akita Diabetic Mice

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    Recently, it has been reported that the Notch pathway is involved in the pathogenesis of diabetic nephropathy. In this study, we investigated the activation of the Notch pathway in Ins2 Akita diabetic mouse (Akita mouse) and the effects of telmisartan, an angiotensin II type1 receptor blocker, on the Notch pathway. The intracellular domain of Notch1 (ICN1) is proteolytically cleaved from the cell plasma membrane in the course of Notch activation. The expression of ICN1 and its ligand, Jagged1, were increased in the glomeruli of Akita mice, especially in the podocytes. Administration of telmisartan significantly ameliorated the expression of ICN1 and Jagged1. Telmisartan inhibited the angiotensin II-induced increased expression of transforming growth factor β and vascular endothelial growth factor A which could directly activate the Notch signaling pathway in cultured podocytes. Our results indicate that the telmisartan prevents diabetic nephropathy through the inhibition of the Notch pathway

    Experimental investigation of performance differences between Coherent Ising Machines and a quantum annealer

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    Physical annealing systems provide heuristic approaches to solving NP-hard Ising optimization problems. Here, we study the performance of two types of annealing machines--a commercially available quantum annealer built by D-Wave Systems, and measurement-feedback coherent Ising machines (CIMs) based on optical parametric oscillator networks--on two classes of problems, the Sherrington-Kirkpatrick (SK) model and MAX-CUT. The D-Wave quantum annealer outperforms the CIMs on MAX-CUT on regular graphs of degree 3. On denser problems, however, we observe an exponential penalty for the quantum annealer (exp(αDWN2)\exp(-\alpha_\textrm{DW} N^2)) relative to CIMs (exp(αCIMN)\exp(-\alpha_\textrm{CIM} N)) for fixed anneal times, on both the SK model and on 50%-edge-density MAX-CUT, where the coefficients αCIM\alpha_\textrm{CIM} and αDW\alpha_\textrm{DW} are problem-class-dependent. On instances with over 5050 vertices, a several-orders-of-magnitude time-to-solution difference exists between CIMs and the D-Wave annealer. An optimal-annealing-time analysis is also consistent with a significant projected performance difference. The difference in performance between the sparsely connected D-Wave machine and the measurement-feedback facilitated all-to-all connectivity of the CIMs provides strong experimental support for efforts to increase the connectivity of quantum annealers.Comment: 12 pages, 5 figures, 1 table (main text); 14 pages, 12 figures, 2 tables (supplementary

    Pancreatic Pseudocysts - Proposal for Diagnosis and Surgical Management -

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    To determine the clinical features and problems presented by a pancreatic pseudocyst, eighteen patients managed at our hospitals since 1980 were reviewed. Males predominated with a ratio of 16: 2, and the average age was 36.2 years. Pseudocyst was located in the pancreatic head in 6, in the body in 6, in the tail in 5 and multiple pseudocysts in one case. The cause of pancreatic pseudocyst was chronic pancreatitis in 9 (including 8 patients with histories of alcoholism), acute pancreatitis in 2 and trauma in 7 patients, respectively. Three patients were associated with pancreatic calculi. Rupture of pseudocyst occurred in one patient with multiple cysts. Autopsy showed acute pancreatic necrosis and penetration to the stomach and duodenum. The indications for surgery were principally cyst-related symptoms(infection, hemorrhage, enlargement and compression of adjacent organs) and differential diagnosis from malignancy. Most of the patients underwent internal drainage ; 9 cystojejunostomy, 2 cystogastrostomy). Three patients underwent cystojejunostomy with longitudinal pancreaticojejunostomy for chronic pancreatitis. Massive hemorrhage after cystogastrostomy occurred in one patient with infected pseudocysts, which required removal of the cysts. Postoperative outcome of the 17 surgical patients was excellent in 16 patients. Only one patient died of pancreatitis associated with alcohol abuse, resulting in a 5.9% mortality. This study suggests that adequate internal drainage by pancreaticojejunostomy to treat the underlying pancreatic disease is most important to obtain an excellent prognosis in patients with pseudocysts

    Surgery for Ulcerative Colitis - A Comparative Retrospective Study -

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    The records of patients with ulcerative colitis (UC) who underwent operation at our hospitals between 1973 and 1995 were reviewed. The clinical course of the disease was the chronic relapsing-remitting type in seven, chronic continuous type in four, acute attack of the relapsing-remitting type in six, and fulminant colitis (toxic megacolon) in two patients. The most common indication for surgery was a condition refractory to conservative therapy. Four patients with massive bleeding, perforation and toxic megacolon underwent emergency operation. The surgical procedures performed were ileoanal anastomosis (IAA) in four, ileoanal canal anastomosis (IACA) in one, ileorectal anastomosis (IRA) in five, proctocolectomy and permanent ileostomy (PCI) in four, and colectomy in five patients. The mortality rate was 5.2%. During follow-up, drug therapy with sulfasalazine (salazosulfapyridine) in colectomy or IRA patients was necessary to control inflammation in the remaining rectal mucosa. One patient with segmental colectomy for severe colitis required removal of the remaining colon 1 year later. Three out of four patients undergoing total proctocolectomy and IAA had a good postoperative course with an average of six bowel movements in 24 hours, but one patient with a long rectal cuff was returned to a PCI because of a cuff abscess. The PCEEA instrument was sufficient to perform IAA and IACA. Carcinoma in the remnant rectum occurred in one patient 20 years after Hartmann\u27s procedure. In conclusion, total proctocolectomy, which has the advantage of removing all diseased mucosa with its potential for inflammation, dysplasia, and carcinoma, may be preferable for extensive long-standing UC
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