• Journal of Korean Neurosurgical Society
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• v.59 no.6
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• pp.590-596
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• 2016

Objective : Rheumatoid arthritis (RA) is a systemic disease that can affect the cervical spine, especially the atlantoaxial region. The present study evaluated the risk factors for atlantoaxial subluxation (AAS) development and progression in patients who have undergone surgical treatment. Methods : We retrospectively analyzed the data of 62 patients with RA and surgically treated AAS between 2002 and 2015. Additionally, we identified 62 patients as controls using propensity score matching of sex and age among 12667 RA patients from a rheumatology registry between 2007 and 2015. We extracted patient data, including sex, age at diagnosis, age at surgery, disease duration, radiographic hand joint changes, and history of methotrexate use, and laboratory data, including presence of rheumatoid factor and the C-reactive protein (CRP) level. Results : The mean patient age at diagnosis was 38.0 years. The mean time interval between RA diagnosis and AAS surgery was $13.6{\pm}7.0$ years. The risk factors for surgically treated AAS development were the serum CRP level (p=0.005) and radiographic hand joint erosion (p=0.009). The risk factors for AAS progression were a short time interval between RA diagnosis and radiographic hand joint erosion (p<0.001) and young age at RA diagnosis (p=0.04). Conclusion : The CRP level at RA diagnosis and a short time interval between RA diagnosis and radiographic hand joint erosion might be risk factors for surgically treated AAS development in RA patients. Additionally, a short time interval between RA diagnosis and radiographic hand joint erosion and young age at RA diagnosis might be risk factors for AAS progression.

• Journal of Food Hygiene and Safety
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• v.4 no.1
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• pp.21-27
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• 1989

This study was performed to investigate the mercury concentration of restaurant meals and to estimate the total dietary intake of mercury. Experimental subjects were 66 cases in 11 kinds of common restaurant meals collected from the Seoul area. Total mercury was determined by Hg-analyzer and two kinds of atomic absorption spectrophotometer (AAS). The results were as follows: 1. Mean value of mercury contents in fluid of meals was about 0.002 ppm and there was no significant difference between the two methods. 2. Mercury concentration of residue by AAS was significantly higher than that by Hg-analyzer. The mean values of mercury concentration were 2.423 ppm, 10.229 ppm and 11.655 ppm by Hg-analyzer, AAS-PE and AAS-Hi, respectively. 3. Dietary intake of mercury from the meals was estimated $7.806\;\mu\textrm{g}/day$ by Hg-analyzer and 31.290, $35.349\;\mu\textrm{g}/day$ by two kinds of AAS. The values were lower than the FAO/WHO limit, $42.9\;\mu\textrm{g}/day$.

• Journal of Environmental Health Sciences
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• v.45 no.3
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• pp.258-266
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• 2019

Objectives: In this study, blood lead was analyzed using graphite furnace atomic absorption spectrometry (GF-AAs) and inductively coupled plasma mass spectrometry (ICP-MS). We tried to examine the difference and consistency of the analytical values and the applicability of the analytical method. Methods: We selected 57 people who agreed to participate in this study. After confirming the linearity of the calibration standard curves in GF-AAs and ICP-MS, the concentrations of lead in quality control material and samples were measured, and the degree of agreement was compared. Results: The detection limit of the ICP-MS was lower than that of GF-AAs. The coefficient of variation of reference materials was shown to be stable in the ICP-MS and GF-AAs. When the correspondence between the two equipments was verified by bias of the analysis values, a concordance was shown, and approximately 98% of the ideal reference lines were present within ${\pm}40%$ of the deflection. Conclusion: GF-AAs showed high sensitivity to single heavy metal analysis, but it took much time and showed higher detection limit than ICP-MS. Therefore, it would be considered necessary to switch to ICP-MS analysis method, considering that the level of lead exposure is gradually decreasing.

• Journal of Korean Neurosurgical Society
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• v.62 no.6
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• pp.661-670
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• 2019

Objective : Rheumatoid arthritis (RA) is known to involve the cervical spine up to 86%. It often causes cervical instability like atlantoaxial subluxation (AAS), subaxial subluxation, and vertical subluxation (VS). In order to find the relation between RA and cord compression, we will evaluate the characteristics and risk factors of basilar invagination (BI) and cervicomedullary junction (CMJ) compression. Methods : From January 2007 to May 2015, 12667 patients administrated to Hanyang University Medical Center. Four thousand three hundred eighty-six patients took cervical X-ray and 250 patients took cervical computed tomography or magnetic resonance imaging. Radiologic parameters, medication records were obtained from 242 patients. Multivariate logistic regression analysis was performed with correlation of CMJ compression, basin-dental interval (BDI), basin-posterior axial line interval (BAI), pannus formation, BI, and AAS. Results : In the point of CMJ compression, atlantodental interval (ADI), posterior-atlantodental interval, BAI, AAS, and BI are relatively highly correlated. Patients with BI have 82 times strong possibility of radiologic confirmed CMJ compression, while AAS has 6-fold and pannus formation has the 3-fold possibility. Compared to the low incidence of BI, AAS and pannus formation have more proportion in CMJ compression. Furthermore, wrist joint erosion was correlated with VS and AAS. Conclusion : BI has a very strong possibility of CMJ compression, while AAS and pannus formation have a high proportion in CMJ compression. Hence bilateral wrist joint erosion can be used as an indicator for the timing of screening test for cervical involvement. We suggest the early recommendation of cervical spine examination for the diagnosis of cervical involvement in order to prevent morbidity and mortality.

• Smart Media Journal
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• v.9 no.4
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• pp.109-117
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• 2020

Recently, with the advent of the 4th industrial revolution, digital twins are emerging as an important technology that connects and integrates physical systems and cyber systems. In this article, we analyzed the major requirements of digital twins required for the construction of digital twins of power equipments in the energy field, focusing on the industry 4.0-based Asset Administration Shell(AAS). However, since not so many studies have been conducted yet on a common platform or demonstration model for implementing digital twins both domestically and internationally, digital twin requirements are analyzed with the consideration of digital twinning of power equipment in the energy field. Also, we suggested necessary procedures and specific functions of AAS to establish a smart energy digital twin in the future by analyzing the core requirements necessary for the construction and designing the AAS design for specific power equipment.

• The korean journal of orthodontics
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• v.53 no.5
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• pp.328-335
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• 2023

Objective: The aim of this study was to determine whether an association between study quality, other study characteristics, and Altmetric Attention Scores (AASs) existed in orthodontic studies. Methods: The Scopus database was searched to identify orthodontic studies published between January 1, 2017, and December 31, 2019. Articles that satisfied the eligibility criteria were included in this study. Study characteristics, including study quality were extracted and entered into a pre-pilot data collection sheet. Descriptive statistics were calculated. On an exploratory basis, random forest and gradient boosting machine learning algorithms were used to examine the influence of article characteristics on AAS. Results: In total, 586 studies with an AAS were analyzed. Overall, the mean AAS of the samples was 5. Twitter was the most popular social media platform for publicizing studies, accounting for 53.7%. In terms of study quality, only 19.1% of the studies were rated as having a high level of quality, with 41.8% of the studies deemed moderate quality. The type of social media platform, number of citations, impact factor, and study type were among the most influential characteristics of AAS in both models. In contrast, study quality was one of the least influential characteristics on the AAS. Conclusions: Social media platforms contributed the most to the AAS for orthodontic studies, whereas study quality had little impact on the AAS.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.33-40
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• 2013

The cement industry brought very severe environment problems with massive carbon dioxide during its production. To solve this problem, attempts on Alkali-Activated Slag (AAS) concrete that perfectly substitutes industrial by-products such as ground granulated blast furnace slag (GGBFS) for cement are being actively made. AAS concrete is possible to have high strength development at room temperature, however, it is difficult to ensure the working time due to the fast setting time and the loss of workabillity because of the alkali reaction. In this study, the early age properties of alkali activated slag mortar are investigated to obtain the fundamental data for AAS concrete application to structural members. The water-binder ratio (W/B) was fixed at 0.35 and sodium hydroxide and waterglass as alkali activator was used. The compressive strength, the flow and the ultrasonic pulse velocity were measured according to the type of superplasticisers, which were naphthalene(N), lignin(L), melamine(M) and PC(P), up to a maximum of 2 percent by the mass of GGBFS. The results showed that adding melamine type of superplasticizer improved the fluidity of AAS mortar without decreasing the compressive strength, while naphthalene and polycarbonate type of superplasticizer had little effect on the fluidity of AAS mortar.

• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.491-501
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• 2018

Objectives: The aims of this study were to compare concentrations and the correspondence of human blood cadmium by using graphite furnace atomic absorption spectrometry (GF-AAS) and inductively coupled plasma-mass spectrometry (ICP-MS), which are representative methods of heavy metal analysis. Methods: We randomly selected 79 people who agreed to participate in the research project. After confirming the linearity of the calibration curves for GF-AAS and ICP-MS, the concentrations of cadmium in a quality control standard material and blood samples were measured, and the correlation and the degree of agreement were compared. Results: The detection limit of ICP-MS (IDL: $0.000{\mu}g/L$, MDL: $0.06{\mu}g/L$) was lower than that of GF-AAS (IDL: $0.085{\mu}g/L$, MDL: $0.327{\mu}g/L$). The coefficient of variation of the quality control standard material showed stable values for both ICP-MS (clinchek-1: 5.35%, clinchek-2: 6.22%) and GF-AAS (clinchek-1: 7.92%, clinchek-2: 5.22%). Recovery was relatively high for both ICP-MS (clinchek-1: 95.1%, clinchek-2: 92.8%) and GF-AAS (clinchek-1: 91.4%, clinchek-2: 98.8%), with more than 90%. The geometric mean, median, and percentile of blood samples were all similar. The agreement of the two instruments compared with the bias of the analytical values found that about 81% of the analytical values were within ${\pm}30%$ of the deviation from the ideal reference line (y=0). As a result of the agreement limit, the value included in the confidence interval was about 94%, which shows high agreement. Conclusion: In this study, we confirmed there was no significant difference in concentrations of a quality control standard material and blood samples. Since ICP-MS showed lower concentrations than GF-AAS at concentrations below the method detection limit of GF-AAS, it is expected that more precise results will be obtained by analyzing blood cadmium with ICP-MS.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.1
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• pp.31-36
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• 2009

The exposure of human beings to toxic trace metals (Cu, Zn) continues to be an important public health issue and concern. This study was conducted to assess the exposure to trace metals (Cu, Zn) in the general Korean population by inductively coupled plasma mass spectrometry (ICP-MS) and Atomic absorption spectrometry (AAS). Serum samples were obtained from 40 healthy volunteers. Specimens were collected in special container and we applied sample processing to minimize contamination. We used ICP-MS and AAS to analyze simultaneously the concentration of metals including copper, zinc. Distribution of trace metal levels in the general healthy population showed lower values. The results in this study can provide background data for clinical studies associated with trace metal exposure in the korean population.

• Journal of Pharmaceutical Investigation
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• v.20 no.1
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• pp.1-5
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• 1990

Effect of an angiotensin inhibitor (AAS; loading dose of 25, 50, $100{\mu}g/kg$ and maintenance dose of 12.5, 25,$50{\mu}g/ka/hr$) on the pharmacokinetics of propranolol (4 mg/kg i.v.) was studied in rabbits. Plasma concentrations and relative bioavailability of propranolal increased upto 127-175% by AAS coinjection. The urinary excretion of propranolol decreased by AAS. Dosage regimen of propranolol should be adjusted when it is administered with AAS.