• Journal of the Korean Solar Energy Society
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• v.36 no.2
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• pp.9-17
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• 2016

In order to examine how accurately the wind farm design software, WindPRO and Meteodyn WT, predict annual energy production (AEP), an investigation was carried out for Seongsan wind farm of Jeju Island. The one-year wind data was measured from wind sensors on met masts of Susan and Sumang which are 2.3 km, and 18 km away from Seongsan wind farm, respectively. MERRA (Modern-Era Retrospective Analysis for Research and Applications) reanalysis data was also analyzed for the same period of time. The real AEP data came from SCADA system of Seongsan wind farm, which was compare with AEP data predicted by WindPRO and Meteodyn WT. As a result, AEP predicted by Meteodyn WT was lower than that by WindPRO. The analysis of using wind data from met masts led to the conclusion that AEP prediction by CFD software, Meteodyn WT, is not always more accurate than that by linear program software, WindPRO. However, when MERRA reanalysis data was used, Meteodyn WT predicted AEP more accurately than WindPRO.

• Journal of Korean Clinical Nursing Research
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• v.24 no.3
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• pp.356-362
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• 2018

Purpose: This study was a retrospective cohort study to evaluate the effect of evidence-based guidelines for catheter dysfunction among hemodialysis patients, Success rate and bleeding complications in catheterization were examined. Methods: We performed a retrospective cohort study, including 94 patients with catheter dysfunction who were receiving hemodialysis at a university hospital; 55 in the control group and 39 in the protocol group. This protocol was composed of the catheter dysfunction assessment, conservative management of catheter dysfunction, drug management of catheter dysfunction, catheter function test and maintenance management. Data were analyzed with a Chi-square test and t-test using SPSS/WIN 23.0 program. Results: The patency rate of the protocol group was significantly higher than that of the control group. The rate of bleeding complications was not statistically significant for either the control group or the protocol group before or after application. Conclusion: The application of the guidelines effectively increased the patency rate of the catheter without bleeding complications. It is hoped that this guideline can be disseminated to nurses nationwide to improve the efficiency of catheter function for hemodialysis patients.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.270-277
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• 2023

Exposure to ionizing radiation induces free radicals in human nails. These free radicals generate a radiation-induced signal (RIS) in electron paramagnetic resonance (EPR) spectroscopy. Compared with the RIS of tooth enamel samples, that in human nails is more affected by moisture and heat, but has the advantages of being sensitive to radiation and easy to collect. The fingernail as a biological sample is applicable in retrospective dosimetry in cases of localized hand exposure accidents. In this study, the dosimetric characteristics of fingernails were analyzed in fingernail clippings collected from Korean donors. The dose response, fading of radiation-induced and mechanically induced signals, treatment method for evaluation of background signal, minimum detectable dose, and minimum detectable mass were investigated to propose a fingernail-EPR dosimetry protocol. In addition, to validate the practicality of the protocol, blind and field experiments were performed in the laboratory and a non-destructive testing facility. The relative biases in the dose assessment result of the blind and field experiments were 8.43% and 21.68% on average between the reference and reconstructed doses. The results of this study suggest that fingernail-EPR dosimetry can be a useful method for the application of retrospective dosimetry in cases of radiological accidents.

• The Korean Journal of Pain
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• v.33 no.3
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• pp.267-274
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• 2020

Background: General anesthesia (GA) has been considered the anesthetic technique which most frequent leads to phantom limb pain (PLP) after a limb amputation. However, these prior reports were limited by small sample sizes. The aims of this study were to evaluate the incidence of PLP according to the various anesthetic techniques used for limb amputation and also to compare the occurrence of PLP according to amputation etiology using the Korean Health Insurance Review and Assessment Service for large-scale demographic information. Methods: The claims of patients who underwent limb amputation were reviewed by analyzing the codes used to classify standardized medical behaviors. The patients were categorized into three groups-GA, neuraxial anesthesia (NA), and peripheral nerve block (PNB)-in accordance with the anesthetic technique. The recorded diagnosis was confirmed using the diagnostic codes for PLP registered within one year after the limb amputation. Results: Finally, 7,613 individuals were analyzed. According to the recorded diagnoses, 362 patients (4.8%) developed PLP after amputation. Among the 2,992 patients exposed to GA, 191 (6.4%) were diagnosed with PLP, whereas 121 (4.3%) of the 2,840 patients anesthetized with NA, and 50 (2.8%) of the 1,781 patients anesthetized under PNB developed PLP. The relative risks were 0.67 (95% confidence interval [CI], 0.53-0.84; P < 0.001) for NA and 0.43 (95% CI, 0.32-0.59; P < 0.001) for PNB. Conclusions: In this retrospective cohort study, using large-scale population-based databases, the incidence rates of PLP after limb amputations were, in the order of frequency, GA, NA, and PNB.

• Journal of radiological science and technology
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• v.42 no.5
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• pp.379-385
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• 2019

Radiation is used for various purposes such as cancer therapy, research of industrial and drugs. However, in case of radiation accidents such as terrorism, collapsing nuclear plant by natural disasters like Fukushima in 2011, very high radiation does expose to human and could lead to death. For this reason, many people are concerning about radiation exposures. Therefore, assessment and research of retrospective radiation dose to human by various path is an necessary task to be continuously developed. Radiation exposure for workers in radiation fields can be generally measured using a personal exposure dosimeter such as TLD, OSLD. However, general people can't be measured radiation doses when they are exposed to radiation. And even if radiation fields workers, when they do not in possession personal dosimeter, they also can't be measured exposure dose immediately. In this study, we conduct retrospective research on reconstruction of dose after exposure by using smart chip card of personal items through Optically Stimulated Luminescence (OSL). The OSL signal of smart chip card shows linear response from 0.06 Gy to 15 Gy and results of fading rate 45 %, 48% for 24 and 48 hours due to the natural emission of radiation in sample, respectively. The minimum detectable limit (MDD) was 0.38 mGy. This values are expected to use as correction values for reconstruction of exposure dose.

• Archives of Craniofacial Surgery
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• v.22 no.3
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• pp.141-147
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• 2021

Background: Arteriovenous malformation (AVM) which is a high-blood-flow lesion with connections between arteries and veins without an intervening capillary bed, is difficult to manage. The ear is the second most common site of extracranial AVM. However, studies regarding the management of this condition remain lacking. The purpose of this study was to share managing experiences in our center and to investigate the treatment effect through a retrospective analysis of cases. Methods: Among 265 patients with AVM treated in our vascular anomalies center between January 2008 and January 2021, 10 patients with auricular AVM were included in the study to investigate the lesion distribution, clinical stage, and treatment methods by performing a retrospective evaluation. Results: Among 10 patients, five patients had AVMs distributed in the upper half of the ear, one patient in the lower half of the ear, and four patients in whole ear, respectively. Seven patients had Schobinger stage II, and three had stage III. One patient received surgical treatment only, four patients received sclerotherapy only, and five patients received both surgical treatment and sclerotherapy. The posttreatment status was checked as controlled in two patients, improved in seven patients, persistent in one patient. There were no worsening patients. Conclusion: Auricular AVM is a disease that is difficult to manage by one specific department, thus requiring a collaborative management effort from multidisciplinary team.

• Journal of Korean Academy of Nursing
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• v.50 no.6
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• pp.837-847
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• 2020

Purpose: The purpose of this study was to investigate the effects of hospital characteristics on employment rate, working period, and retirement of ward nurses in Korea through a retrospective cohort study based on HIRAS data. Methods: Data were obtained from a report on medical care institutions of Health Insurance Review & Assessment Service (HIRAS). Data from 259,941 nurses who were working for a day or more from January 1, 2012, to December 31, 2016, at 2,942 medical care institutions were analyzed. Life table method analysis, Kaplan-Meier analysis, and Cox proportional hazard regression analysis were conducted. Results: The employment rates of 5 yeas and 10 years for the total sample were 38% and 28%, respectively. The estimated mean value of the working period was 3,642.7 days (SE: 17.4 days). Cox proportional hazard regression analyses revealed that nurses who were working at the general hospital/hospital, clinic, and nursing hospital were more likely to leave the hospital compared to those who were working at the 3rd general hospital. Nurses who were working at the medical institutions which were located in cities and countries, established by the private foundation, rated lower levels of nursing, and owned an insufficient number of beds, nurses and doctors were more likely to leave their workplace compared to those of the counterparts. Conclusion: This study indicates that hospital characteristics may play a significant role in retirement and working period of ward nurses in Korea. The improvement of hospital conditions to reduce ward nurses' retirement are needed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.398-422
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• 2017

Objectives: The major aim of this study is to construct the database of retrospective exposure assessment for crystalline silica through reviews of literatures in South Korea. Methods: Airborne concentrations of crystalline silica were collected using an academic information search engine, Research Information Service System(RISS), operated by the Korea Education & Research Information Service(KERIS). The key words used for the literature search were 'silica', 'crystalline silica', 'cristobalite', 'quartz' and 'tridymite'. A total number of 18 published documents with the information of crystalline silica level in air or bulk samples were selected and used to estimate retrospective exposures to crystalline silica. Weighted arithmetic mean(WAM) calculated across studies was summarized by industry type. Industries were classified according to Korea Standard Industrial Classification(KSIC) using information provided in the literature. Results: A total of 2,131 individual air sampling data measured from 1987 to 2012 were compiled. Compiled individual measurement data consisted of 827 respirable crystalline silica (RCS), 31 total crystalline silica(TCS), 24 crystalline silica(CS), 778 respirable dust(RD) and 471 total dust(TD). Most of RCS measurements(68.9%) were collected from 'cast of metals(KSIC 243)'. Comparing industry types, 'mining coal and lignite(KISC 051)' showed the highest WAM concentration of RCS, $0.14mg/m^3$, followed by $0.11mg/m^3$ of 'manufacture of other non-metallic mineral products(KSIC 239)', $0.108mg/m^3$ of 'manufacture of ceramic ware(KSIC 232)', $0.098mg/m^3$ of 'heavy construction(KSIC 412)' and $0.062mg/m^3$ of 'cast of metals(KSIC 243)'. In terms of crystalline silica contents in airborne dust, 'manufacture of other non-metallic mineral products(KSIC 239)' showed the highest value of 7.3%(wt/wt), followed by 6.8% of 'manufacture of ceramic ware(KSIC 232)', 5.8% of 'mining of iron ores(KSIC 061)', 4.9% of 'cast of metals(KSIC 243)' and 4.5% of 'heavy construction(KSIC 412)'. WAM concentrations of RCS had no consistent trends over time from 1994 ($0.26mg/m^3$) to 2012 ($0.12mg/m^3$). Conclusion: The data set related RCS exposure level by industries can be used to determine not only the possibility of retrospective exposure to RCS, but also to evaluate the level of quantitative retrospective exposure to RCS.

• The Journal of Korean Medicine
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• v.31 no.5
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• pp.1-11
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• 2010

Objectives: This study aimed to evaluate any clinical studies regarding rhinitis published by the Korean Oriental Medical Society and its sub-societies for future rigorous clinical research. Methods: Every article relevant to rhinitis was initially obtained from journals of the Korean Oriental Medical Society and its sub-societies by electronic search at journal web sites or manual searches. Journals were limited to those registered with the Korea Research Foundation. From initial findings, two independent reviewers selected clinical articles and these articles were further analyzed separately by predefined criteria according to prospective and retrospective studies. For prospective studies, quality assessment was also conducted. Results: From 36 initially obtained articles, 17 were finally analyzed. 2 articles were randomized controlled studies, 6 articles were prospective whereas 9 were retrospective. In the prospective articles, there were no randomized controlled trials and the other non-randomized studies had no control group with several problems of quality regarding pre-calculated study size and unbiased assessment. None of the retrospective studies described rhinitis diagnosis objectively and outcome measures were either non-relevant to rhinitis or non-validated. Conclusions: Further well-designed randomized controlled studies for rhinitis are mandatory and more rigorous non-randomized controlled studies should be conducted.

• Journal of Periodontal and Implant Science
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• v.48 no.4
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• pp.251-260
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• 2018

Purpose: The aim of this retrospective cross-sectional study was to evaluate whether salivary findings of active matrix-metalloproteinase 8 (aMMP-8) chairside (point of care; POC) tests were associated with periodontal risk assessment parameters in patients receiving supportive periodontal therapy (SPT). Methods: A total of 125 patients receiving regular SPT were included, and their records were examined. The following inclusion criteria were used: a diagnosis of chronic periodontitis, at least 1 non-surgical periodontal treatment (scaling and root planning) with following regular SPT (minimum once a year), at least 6 remaining teeth, and clinical and aMMP-8 findings that were obtained at the same appointment. In addition to anamnestic factors (e.g., smoking and diabetes), oral hygiene indices (modified sulcus bleeding index [mSBI] and approximal plaque index), periodontal probing depth simultaneously with bleeding on probing, and dental findings (number of decayed, missing, and filled teeth) were recorded. Salivary aMMP-8 levels were tested using a commercial POC test system (Periomarker, Hager & Werken, Duisburg, Germany). Statistical analysis was performed using the t-test, Mann-Whitney U test, Fisher's exact test, and ${\chi}^2$ test, as appropriate (P<0.05). Results: Only the mSBI was significantly associated with positive salivary aMMP-8 findings (aMMP-8 positive: $27.8%{\pm}20.9%$ vs. aMMP-8 negative: $18.0%{\pm}14.5%$; P=0.017). No significant associations were found between aMMP-8 and smoking, diabetes, periodontal parameters, or parameters related to the maintenance interval (P>0.05). Conclusions: Salivary aMMP-8 chairside findings were not associated with common parameters used for periodontal risk assessment in patients receiving SPT. The diagnostic benefit of POC salivary aMMP-8 testing in risk assessment and maintenance interval adjustment during SPT remains unclear.