270 research outputs found

    Multidimensional Discretization??? Event-Codification ????????? ????????? ????????? ?????? ?????? ??????

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    In the literature, various stochastic anomaly detection methods, such as limit checking and PCAbased approaches, have been applied to weld defect detection. However, it is still a challenge to identify meaningful defect patterns from very limited sensor signals of laser welding, characterized by intermittent, discontinuous, very short, and non-stationary random signals. In order to effectively analyze the physical characteristics of laser weld signals: plasma intensity, weld pool temperature, and back reflection, we first transform the raw data of laser weld signals into the form of event logs. This is done by multidimensional discretization and event-codification, after which the event logs are decoded to extract weld defect patterns by Naïve Bayes classifier. The performance of the proposed method is examined in comparison with the commercial solution of PRECITEC???s LWM TM and the most recent PCA-based detection method. The results show higher performance of the proposed method in terms of sensitivity (1.00) and specificity (0.98).clos

    Effect of bioactive glass addition on the physical properties of mineral trioxide aggregate

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    Background The addition of bioactive glass (BG), a highly bioactive material with remineralization potential, might improve the drawback of weakening property of mineral trioxide aggregates (MTA) when it encounters with body fluid. This study aims to evaluate the effect of BG addition on physical properties of MTA. Methods ProRoot (MTA), and MTA with various concentrations of BG (1, 2, 5 and 10% BG/MTA) were prepared. Simulated body fluid (SBF) was used to investigate the effect of the storage solution on dentin remineralization. Prepared specimens were examined as following; the push-out bond strength to dentin, compressive strength, setting time solubility and X-ray diffraction (XRD) analysis. Results The 2% BG/MTA showed higher push-out bond strengths than control group after 7 days of SBF storage. The 2% BG/MTA exhibited the highest compressive strength. Setting times were reduced in the 1 and 2% BG/MTA groups, and solubility of all experimental groups were clinically acceptable. In all groups, precipitates were observed in dentinal tubules via SEM. XRD showed the increased hydroxyapatite peaks in the 2, 5 and 10% BG/MTA groups. Conclusion It was verified that the BG-added MTA increased dentin push-out bond strength and compressive strength under SBF storage. The addition of BG did not negatively affect the MTA maturation reaction; it increased the amount of hydroxyapatite during SBF maturation.This research was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) & funded by the Korean government (MSIP&MOHW) (No. 2017M3A9E4048170) and NRF (No.2019R1G1A1100082). This work was also supported by a grant from Kyung Hee University in 2020 (KHU-20201233)

    A Pilot Study of the Effectiveness of Medical Emergency System Implementation at a Single Center in Korea

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    Background An automatic alarm system was developed was developed for unexpected vital sign instability in admitted patients to reduce staffing needs and costs related to rapid response teams. This was a pilot study of the automatic alarm system, the medical emergency system (MES), and the aim of this study was to determine the effectiveness of the MES before expanding this system to all departments. Methods This retrospective, observational study compared the performance of patients admitted to the pulmonary department at a single center using patient data from three 3-month periods (before implementation of the MES, December 2013-February 2014; after implementation of the MES, December 2014-February 2015 and December 2015-February 2016). Results A total of 571 patients were admitted to the pulmonary department during the three observation periods. During this pilot study, the MES automatically issued 568 alarms for 415 admitted patients. There was no significant difference in the rate of cardiopulmonary resuscitation (CPR) before and after application of the MES. The mortality rate also did not change. However, it appeared that CPR was prevented in four patients admitted from the general ward to the intensive care unit (ICU) during MES implementation. The median length of hospital stay and median length of ICU stay were not significantly different before and after MES implementation. Conclusions Although we did not find a significant improvement in outcomes upon MES implementation, the CPR rate and mortality rate did not increase despite increased comorbidities. This was a small pilot study and, based on these results, we believe that the MES may have significant effects in longer-term and larger-scale studies

    The effects of different pilot-drilling methods on the mechanical stability of a mini-implant system at placement and removal: a preliminary study

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    Objective: To investigate the effects of different pilot-drilling methods on the biomechanical stability of self-tapping mini-implant systems at the time of placement in and removal from artificial bone blocks. Methods: Two types of artificial bone blocks (2-mm and 4-mm, 102-pounds per cubic foot [102-PCF] polyurethane foam layered over 100-mm, 40-PCF polyurethane foam) were custom-fabricated. Eight mini-implants were placed using the conventional motor-driven pilot-drilling method and another 8 mini-implants were placed using a novel manual pilot-drilling method (using a manual drill) within each of the 2-mm and 4-mm layered blocks. The maximum torque values at insertion and removal of the mini-implants were measured, and the total energy was calculated. The data were statistically analyzed using linear regression analysis. Results: The maximum insertion torque was similar regardless of block thickness or pilot-drilling method. Regardless of the pilot-drilling method, the maximum removal torque for the 4-mm block was statistically higher than that for the 2-mm block. For a given block, the total energy at both insertion and removal of the mini-implant for the manual pilot-drilling method were statistically higher than those for the motor-driven pilot-drilling method. Further, the total energies at removal for the 2-mm block was higher than that for the 4-mm block, but the energies at insertion were not influenced by the type of bone blocks. Conclusions: During the insertion and removal of mini-implants in artificial bone blocks, the effect of the manual pilot-drilling method on energy usage was similar to that of the conventional, motor-driven pilot-drilling method. (Korean J Orthod 2011;41(5):354-360)Supported by a grant from Kyung Hee University in 2010 (KHU-20100696).

    Combination of Antiemetics for the Prevention of Postoperative Nausea and Vomiting in High-Risk Patients

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    It was previously reported that the Korean predictive model could be used to identify patients at high risk of postoperative nausea and vomiting (PONV). This study investigated whether PONV in the high-risk and very high-risk patients identified by the Korean predictive model could be prevented by multiple prophylactic antiemetics. A total of 2,456 patients were selected from our previous PONV study and assigned to the control group, and 374 new patients were recruited consecutively to the treatment group. Patients in each group were subdivided into two risk groups according to the Korean predictive model: high-risk group and very high-risk group. Patients in the treatment group received an antiemetic combination of dexamethasone 5 mg (minutes after induction) and ondansetron 4 mg (30 min before the end of surgery). The incidences of PONV were examined at two hours after the surgery in the postanesthetic care unit and, additionally, at 24 hr after the surgery in the ward, and were analyzed for any differences between the control and treatment groups. The overall incidence of PONV decreased significantly from 52.1% to 23.0% (p≤0.001) after antiemetic prophylaxis. Specifically, the incidence decreased from 47.3% to 19.4% (p≤0.001) in the high-risk group and from 61.3% to 28.3% (p≤0.001) in the very high-risk group. Both groups showed a similar degree of relative risk reductions: 59.0% vs. 53.8% in the high-risk and very high-risk groups, respectively. The results of our study showed that the antiemetic prophylaxis with the combination of dexamethasone and ondansetron was effective in reducing the occurrence of PONV in both high-risk and very high-risk patients

    Improved Gastrointestinal Symptoms and Quality of Life after Conversion from Mycophenolate Mofetil to Enteric-Coated Mycophenolate Sodium in Renal Transplant Patients Receiving Tacrolimus

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    It is reported that a conversion from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) relieves gastrointestinal (GI) symptom burden and improves health-related quality of life (HRQoL). However, it is unclear whether renal transplant recipients using tacrolimus receive the same benefit from the conversion. In this prospective, multi-center, open-label trial, patients were categorized into two groups by their GI symptom screening. Equimolar EC-MPS (n=175) was prescribed for patients with GI burdens; those with no complaints remained on MMF (n=83). Gastrointestinal Symptom Rating Scale (GSRS) and Gastrointestinal Quality of Life Index (GIQLI) were evaluated at baseline and after one month. Patients and physicians completed Overall Treatment Effect (OTE) at one month. EC-MPS-converted patients had worse GSRS and GIQLI scores at baseline than MMF-continued patients (all P<0.001). Significant improvements in GSRS and GIQLI scores were observed for EC-MPS-converted patients at one month, but MMF-continued patients showed worsened GSRS scores (all P<0.05). OTE scale indicated that EC-MPS patients improved in overall GI symptoms and HRQoL more than MMF patients did (P<0.001). In tacrolimus-treated renal transplant recipients with GI burdens, a conversion from MMF to EC-MPS improves GI-related symptoms and HRQoL

    Effects of remote ischemic postconditioning on hepatic injury in lipopolysaccharide-induced endotoxemic rats

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    Background Remote ischemic postconditioning (RIPoC) is induced by several cycles of brief, reversible, mechanical blood flow occlusion, and reperfusion of the distal organs thereby protecting target organs. We investigated if RIPoC ameliorated liver injury in a lipopolysaccharide (LPS)-induced endotoxemic rats. Methods Protocol 1) Rats were administered LPS and samples collected at 0, 2, 6, 12, and 18 h. 2) After RIPoC at 2, 6, and 12 h (L+2R+18H, L+6R+18H, and L+12R+18H), samples were analyzed at 18 h. 3) RIPoC was performed at 2 h, analysis samples at 6, 12, 18 h (L+2R+6H, L+2R+12H, L+2R+18H), and RIPoC at 6 h, analysis at 12 h (L+6R+12H). 4) Rats were assigned to a control group while in the RIPoC group, RIPoC was performed at 2, 6, 10, and 14 h, with samples analyzed at 18 h. Results Protocol 1) Liver enzyme, malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), and nuclear factor-κB (NF-κB) levels increased while superoxide dismutase (SOD) levels decreased over time. 2) Liver enzyme and MDA levels were lower while SOD levels were higher in L+12R+18H and L+6R+18H groups when compared with L+2R+18H group. 3) Liver enzyme and MDA levels were lower while SOD levels were higher in L+2R+6H and L+6R+12H groups when compared with L+2R+12H and L+2R+18H groups. 4) Liver enzyme, MDA, TNF-α, and NF-κB levels were lower while SOD levels were higher in RIPoC group when compared with control group. Conclusions RIPoC attenuated liver injury in the LPS-induced sepsis model by modifying inflammatory and oxidative stress response for a limited period
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