31 research outputs found

    A computer-aided simulation tool based on Petri nets for the design and analysis of FMSs

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    Discrete-event simulation has been recognized as an invaluable tool in analyzing and designing FMSs. In this dissertation, a computer-aided simulation tool based on Petri nets is presented to facilitate simulation projects in the manufacturing area. For modeling and simulation of FMSs, Conserved nets which are a subclass of Petri nets are proposed and implemented. The structural characteristics and liveness conditions of Conserved nets are investigated. While hardware components are modeled by hierarchically-classified Petri net objects, high-level, real-time control systems in FMSs are separately modeled and integrated with a Petri net model to resolve conflicts occurring in Petri net execution. The structure of the Petri net-based simulation tool is presented. Also, the use of the simulation tool is illustrated with several case studies including performance comparison of push- and pull-based AGV dispatching rules in an FMS. Finally, strengths and weaknesses of the developed simulation tool are discussed including areas for future study

    Spinal cord injury after conducting transcatheter arterial chemoembolization for costal metastasis of hepatocellular carcinoma

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    Transcatheter arterial chemoembolization (TACE) has been used widely to treat patients with unresectable hepatocellular carcinoma. However, this method can induce various adverse events caused by necrosis of the tumor itself or damage to nontumor tissues. In particular, neurologic side effects such as cerebral infarction and paraplegia, although rare, may cause severe sequelae and permanent disability. Detailed information regarding the treatment process and prognosis associated with this procedure is not yet available. We experienced a case of paraplegia that occurred after conducting TACE through the intercostal artery to treat hepatocellular carcinoma that had metastasized to the rib. In this case, TACE was attempted to relieve severe bone pain, which had persisted even after palliative radiotherapy. A sudden impairment of sensory and motor functions after TACE developed in the trunk below the level of the sternum and in both lower extremities. The patient subsequently received steroid pulse therapy along with supportive care and continuous rehabilitation. At the time of discharge the patient had recovered sufficiently to enable him to walk by himself, although some paresthesia and spasticity remained

    N-benzyl-N-methyldecan-1-amine and its derivative mitigate 2,4- dinitrobenzenesulfonic acid-induced colitis and collagen-induced rheumatoid arthritis

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    As our previous study revealed that N-benzyl-N-methyldecan-1-amine (BMDA), a new molecule originated from Allium sativum, exhibits anti-neoplastic activities, we herein explored other functions of the compound and its derivative [decyl-(4-methoxy-benzyl)-methyl-amine; DMMA] including anti-inflammatory and anti-oxidative activities. Pretreatment of THP-1 cells with BMDA or DMMA inhibited tumor necrosis factor (TNF)-α and interleukin (IL)-1β production, and blocked c-jun terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), MAPKAP kinase (MK)2 and NF-κΒ inflammatory signaling during LPS stimulation. Rectal treatment with BMDA or DMMA reduced the severity of colitis in 2,4-dinitrobenzenesulfonic acid (DNBS)-treated rat. Consistently, administration of the compounds decreased myeloperoxidase (MPO) activity (representing neutrophil infiltration in colonic mucosa), production of inflammatory mediators such as cytokine-induced neutrophil chemoattractant (CINC)-3 and TNF-α, and activation of JNK and p38 MAPK in the colon tissues. In addition, oral administration of these compounds ameliorated collagen-induced rheumatoid arthritis (RA) in mice. The treatment diminished the levels of inflammatory cytokine transcripts, and protected connective tissues through the expression of anti-oxidation proteins such as nuclear factor erythroid-related factor (Nrf)2 and heme oxygenase (HO)1. Additionally, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels did not differ between the BMDA- or DMMA-treated and control animals, indicating that the compounds do not possess liver toxicity. Taken together, these findings propose that BMDA and DMMA could be used as new drugs for curing inflammatory bowel disease (IBD) and RA

    A computer-aided simulation tool based on Petri nets for the design and analysis of FMSs

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    Discrete-event simulation has been recognized as an invaluable tool in analyzing and designing FMSs. In this dissertation, a computer-aided simulation tool based on Petri nets is presented to facilitate simulation projects in the manufacturing area. For modeling and simulation of FMSs, Conserved nets which are a subclass of Petri nets are proposed and implemented. The structural characteristics and liveness conditions of Conserved nets are investigated. While hardware components are modeled by hierarchically-classified Petri net objects, high-level, real-time control systems in FMSs are separately modeled and integrated with a Petri net model to resolve conflicts occurring in Petri net execution. The structure of the Petri net-based simulation tool is presented. Also, the use of the simulation tool is illustrated with several case studies including performance comparison of push- and pull-based AGV dispatching rules in an FMS. Finally, strengths and weaknesses of the developed simulation tool are discussed including areas for future study.</p

    Gastrectomy for the treatment of refractory gastric ulceration after radioembolization with Y microspheres

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    Transcatheter arterial radioembolization (TARE) with Yttrium-90 (90Y)-labeled microspheres has an emerging role in treatment of patients with unresectable hepatocellular carcinoma. Although complication of TARE can be minimized by aggressive pre-evaluation angiography and preventive coiling of aberrant vessels, radioembolization-induced gastroduodenal ulcer can be irreversible and can be life-threatening. Treatment of radioembolization-induced gastric ulcer is challenging because there is a few reported cases and no consensus for management. We report a case of severe gastric ulceration with bleeding that eventually required surgery due to aberrant deposition of microspheres after TARE

    Community mental health status six months after the Sewol ferry disaster in Ansan, Korea

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    OBJECTIVES: The disaster of the Sewol ferry that sank at sea off Korea’s southern coast of the Yellow Sea on April 16, 2014 was a tragedy that brought grief and despair to the whole country. The aim of this study was to evaluate the mental health effects of this disaster on the community of Ansan, where most victims and survivors resided. METHODS: The self-administered questionnaire survey was conducted 4 to 6 months after the accident using the Korean Community Health Survey system, an annual nationwide cross-sectional survey. Subjects were 7,076 adults (≥19 years) living in two victimized communities in Ansan, four control communities from Gyeonggi-do, Jindo and Haenam near the accident site. Depression, stress, somatic symptoms, anxiety, and suicidal ideation were measured using the Center for Epidemiologic Studies-Depression Scale, Brief Encounter Psychosocial Instrument, Patient Health Questionnaire-15, and Generalized Anxiety Disorder 7-Item Scale, respectively. RESULTS: The depression rate among the respondents from Ansan was 11.8%, and 18.4% reported suicidal ideation. Prevalence of other psychiatric disturbances was also higher compared with the other areas. A multiple logistic regression analysis revealed significantly higher odds ratios (ORs) in depression (1.66; 95% confidence interval [CI], 1.36 to 2.04), stress (1.37; 95% CI, 1.10 to 1.71), somatic symptoms (1.31; 95% CI, 1.08 to 1.58), anxiety (1.82; 95% CI, 1.39 to 2.39), and suicidal ideation (1.33; 95% CI, 1.13 to 1.56) compared with Gyeonggi-do. In contrast, the accident areas of Jindo and Haenam showed the lowest prevalence and ORs. CONCLUSIONS: Residents in the victimized area of Ansan had a significantly higher prevalence of psychiatric disturbances than in the control communities

    Outcome of Intermittent Thoracentesis versus Pigtail Catheter Drainage for Hepatic Hydrothorax

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    Background/Aims: The management of hepatic hydrothorax (HH) remains a challenging clinical scenario with suboptimal options. We investigated the effect and safety of pigtail catheter drainage compared to intermittent thoracentesis. Methods: This multicenter, retrospective study included 164 cirrhotic patients with recurrent pleural effusion from March 2012 to June 2017. Patients with neoplasms, cardiopulmonary disease, and infectious conditions were excluded. We compared the clinical outcomes of pigtail catheter drainage versus thoracentesis for variables including complications related to procedures, overall survival, and re-admission rates. Results: A total of 164 patients were divided into pigtail catheter (n = 115) and thoracentesis (n = 49) groups. During the follow-up period of 6.93 months after discharge, 98 patients died (pigtail; n = 47 vs. thoracentesis; n = 51). The overall survival (p = 0.61) and 30-day mortality (p = 0.77) rates were similar between the pigtail catheter and thoracentesis groups. Only MELD scores were associated with overall survival (adjusted HR, 1.08; p p = 0.7). A total of five complications occurred, including four total cases of bleeding (one patient in the pigtail catheter group and three in the thoracentesis group) and one case of empyema in the pigtail catheter group. Conclusions: Pigtail catheter drainage is not inferior to that of intermittent thoracentesis for the management of HH, proving it may be an effective and safe clinical option
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