• Korean Journal of Radiology
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• 제23권11호
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• pp.1102-1111
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• 2022

Objective: To evaluate the ultrasonography (US) features for diagnosing metastasis in cervical lymph nodes (LNs) in patients with thyroid cancer and compare the US classification of risk of LN metastasis between European and Korean guidelines. Materials and Methods: From January 2014 to December 2018, US-guided fine-needle aspiration was performed on 836 LNs from 714 patients for the preoperative nodal staging of thyroid cancer. The US features of LNs were retrospectively reviewed for the following features: size, presence of hilum, margin, orientation, cystic change, punctate echogenic foci (PEF), large echogenic foci, eccentric cortical thickening, abnormal vascularity, and cortical hyperechogenicity. A multiple logistic regression analysis was performed to identify the independent US features for the diagnosis of metastatic LNs. The diagnostic performance of independent US features was subsequently evaluated. LNs were categorized according to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and European Thyroid Association (ETA) guidelines, and the correlation between the two sets of classifications was assessed. Results: Absence of the hilum, presence of cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity were independent US features of metastatic LNs. Cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity showed high specificity (86.8%-99.6%). The absence of the hilum had the highest sensitivity yet low specificity (66.4%). When LNs were classified according to the ETA guidelines and K-TIRADS, they yielded similar categorizations of malignancy risks and were strongly correlated (Spearman coefficient, 0.9766 [95% confidence interval, 0.973-0.979]). According to the ETA guidelines, 9.8% (82/836) of LNs were classified as "not specified." Conclusion: Absence of hilum, cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity were independent US features suggestive of metastatic LNs in thyroid cancer. Both K-TIRADS and the ETA guidelines provided similar risk stratification for metastatic LNs with a high correlation; however, the ETA guidelines failed to classify 9.8% of LNs into a specific risk stratum. These results may provide a basis for revising LN classification in future guidelines.

• 한국물환경학회지
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• 제33권4호
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• pp.424-433
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• 2017

The purpose of this study is to understand the changes on species composition of the epilithic diatoms and the appearance of morphological abnormalities in the upper region of the Nakdong River where heavy metal inflow is observed. The samples were collected once a week for a month of September 2016 from selecting 7 sampling stations. The heavy metals of cadmium (Cd) and arsenic (As) were not detected during the survey period, but zinc (Zn) was detected in st.4 - st.6 with the range of $0.015{\sim}0.188mg\;L^{-1}$. Metal sensitive species such as Achnanthes convergens, Cocconeis placentula, Cocconeis placentula var. euglypta, Cocconeis placentula var. lineata showed high dominance in st.1 - st.3, st.7. However, metal tolerant species such as Nitzschia palea, Achnanthes minutissima showed high dominance in st.4 - st.6. It is concluded that heavy metal inflow directly affects the changes in species composition of epilithic diatoms. As a result of CCA, the characteristics of the sampling sites were divided into 3 groups. Group 1 was represented the non-detected Zn sites with C. placentula, C. placentula var. euglypta, C. placentula var. lineata. Group 2 was showed the detected Zn sites with Navicula minima and Nitzschia palea. Group 3 was included st.3 - st.7 on 4th week that was stabilized the community structure. Total 8 taxa of abnormal frustules observed. This occurrence of abnormal frustules reflected the temporal and quantitative indicators of heavy metal pollution, in particular, it was confirmed that genus Fragilaria, which has a high abnormality according to heavy metal pollution, can be used as an indicator species.

• 자원환경지질
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• 제51권4호
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• pp.393-400
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• 2018

2016년 9월 12일 발생한 $M_L5.8$ 경주 지진과 2017년 11월 15일 $M_L5.4$ 포항 지진은 국내에 지진 예측가능성에 대한 관심을 불러일으켰다. 지진 예측의 가능성에 대한 회의적인 의견이 있음에도 불구하고 세계적으로는 지진 발생 전 이상 변동을 보이는 인자들의 관측과 평가가 지속되고 있다. 본 연구에서는 양산단층대의 지하수위 정밀 관측을 위해 시범 운용 중인 양산 지하수 정밀관측공에서 2015년부터 관측된 지하수의 비정상적인 상승 사례를 보고하였다. 이 이상 변동은 다양한 수리지질학적 인자들을 고려하였을 때 지진 전조일 가능성이 높다고 판단된다. 그럼에도 불구하고 단일 관정의 단일 요소에서 나타난 자료만으로 지진 전조를 섣불리 판단할 수 없다. 장기적으로는 전조 현상 연구와 평가를 위한 전문기구의 설립이 필요하다.

• 항공우주시스템공학회지
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• 제13권5호
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• pp.79-86
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• 2019

회전익 항공기의 충돌방지등은 항공기 운용 중 충돌을 방지하기 위한 목적으로 사용되며, 비행 안전성을 확보하기 위한 핵심 구성품이다. 한국형 기동헬기(KUH)의 충돌방지등은 상부등과 하부등으로 구성되며, 충돌방지등 전원공급기와 항공기에 함께 장착되어 운용된다. 그리고 충돌방지등은 밝기 조절 및 선택적 점등이 가능한 이중 구조로 설계되었다. 항공기 납품 후 운용 과정에서 충돌방지등의 이상점 등이 발생하였고, 이러한 현상을 해소하기 위하여 항공기 체계/구성품 단위의 종합 검토를 수행하였다. 본 논문에서는 충돌방지등의 이상점등이 발생한 원인을 분석하였고, 설계 개선방안을 제시하였다. 그리고 설계 개선방안에 대한 타당성을 구성품 및 항공기 체계 지상 및 비행시험으로 입증하였다.

• 한국분말재료학회지
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• 제29권2호
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• pp.110-117
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• 2022

The grain growth behavior in the (1-x)K_0.5Na_0.5NbO₃-xCaZrO₃ (KNNCZ-x) system is studied as a function of the amount of CZ and grain shape. The (1-x)K_0.5Na_0.5NbO₃-xCaZrO₃ (KNNCZ-x) powders are synthesized using a conventional solid-state reaction method. A single orthorhombic phase is observed at x = 0 - 0.03. However, rhombohedral and orthorhombic phases are observed at x = 0.05. The grain growth behavior changes from abnormal grain growth to the suppression of grain growth as the amount of CaZrO₃ (CZ) increases. With increasing CZ content, grains become more faceted, and the step-free energy increases. Therefore, the critical growth driving force increases. The grain size distribution broadens with increasing sintering time in KNNCZ-0.05. As a result, some large grains with a driving force larger than the critical driving force for growth exhibit abnormal grain growth behavior during sintering. Therefore, CZ changes the grain growth behavior and microstructure of KNN. Grain growth at the faceted interface of the KNNCZ system occurs via two-dimensional nucleation and growth.

• 대한유전성대사질환학회지
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• 제22권2호
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• pp.53-57
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• 2022

다양한 아미노산 및 지질 대사 질환에서 피부와 모발의 변화가 관찰된다. 탈모증이 관찰되는 경우 장병성 선단피부염(아연 대사 장애), 비오티니다아제 결핍증 (비타민 B), 다발성 카르복실라제 결핍증, acrodermatitis acidemica 등 아미노산 및 비타민 대사 결함을 의심해볼 수 있다. 또한 부서지기 쉬운 모발이 관찰되는 경우 아르기니노숙신산뇨증 또는 시트룰린혈증 및 점액다당증을 의심해볼 수 있다. 건조하고 두꺼워진 인설을 가진 피부 또는 비늘증은 중성지질 축적 질환, 지방산 대사 장애, 콜레스테롤 합성 및 대사 장애와 관련하여 나타날 수 있다. 수포성 병변은 장병성 선단피부염, 비오티니다아제 결핍증, 홀로카르복실라제 합성효소 결핍증, acrodermatitis acidemica 등에서 나타날 수 있다.

• 한국산학기술학회논문지
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• 제18권8호
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• pp.317-323
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• 2017

본 연구의 목적은 요통으로 추간공 접근법과 추궁간판 접근법을 사용하여 요부 경막외 신경차단술을 받은 환자를 대상으로 시술 후 자기공명영상 소견이 어떻게 다른지 조사하는 것이었다. 연구 방법은 신경차단술 후 자기공명영상의 이상 소견에 대해 분석한 관찰 연구이다. 연구 대상자는 2007년 1월에서 2016 12월 사이에 일개 대학병원 통증클리닉에서 요부 경막외 신경차단술 24시간 후에 요추부 자기공명영상을 촬영한 78명의 환자를 대상으로 하였다. 신경차단술을 받은 대상자 중에서 추궁간판 접근법을 사용한 환자는 36명이었고, 추간공 접근법을 사용한 환자는 42명이었다. 경막외 신경차단술 후 자기공명영상에서 비정상적인 소견을 보인 환자들의 비율은 추간공 접근법을 사용한 군(7%)에 비해 추궁간판 접근법을 사용한 군(53%)에서 많았다. 비정상적인 자기공명영상 소견은 경막외 공기, 유체, 연부 조직의 변화, 바늘 자국 등이었다. 전체 비정상소견 중에서는 경막외 공기가 72%로 다수를 차지했다. 위의 연구결과를 고려할 때 요부 경막외 신경차단술을 시행 후 24시간 이내에 자기공명영상을 촬영할 경우에는, 시술 시 추간공 접근법을 이용하는 것이 자기공명영상의 판독 오류 또는 해석의 어려움을 줄이는데 도움이 될 것이다. 또한 추궁간판 접근법을 이용하여 시술하는 경우에는 자기공명영상에서 경막외 공기 등의 이상 소견이 발견될 가능성에 주의할 필요가 있다.

• 생물정신의학
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• 제11권2호
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• pp.117-126
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• 2004

Objects:It has been reported that the incidence of tardive dyskinesia(TD), the remarkable abnormal involuntary movement, was higher in the schizophrenics with high blood sugar levels and that TD had been improved by small amount of insulin-injection for 90 days. And also it was generally known that the blood lipids were higher in the schizophrenics with tardive dyskinesia. Thus, we tried to replicate the correlations of abnormal involuntary movements with blood sugar levels and blood lipids in chronic schizophrenics treated with antipsychotics. Methods:Thirty-eight male schizophrenic inpatients who were stable in clinical state with medications, were included. The patients who had been already diagnosed as diabetes mellitus(DM), organic brain disorder, substance- related disorder, physical illness were excluded and also we excluded female patients to remove the hormonal effect on TD. Eleven patients who ranked higher(above five) in the Abnormal Involuntary Movement Scale(AIMS) were assigned into 2 groups, a dibenese group and a placebo group. Diabinese or placebos were administrated for 3 weeks with antipsychotics and AIMS was rechecked. Results:There were no correlations between the total AIMS scores and blood sugar and lipids levels in all subjects. The means of total and subscale scores(objective, face, and extremity) of AIMS did not reveal statistical significances between diabinese and placebo groups. However(total, jaw, face, upper arm, and objective feeling), were statistically higher in the diabinese group than those in the placebo group. And correlations of total cholesterol(TC) with fast blood sugar(FBS), weight with body mass index(BMI) and waist, total glycerol (TG) with BMI were statistically significant. Conclusion:In this study, there were statistical significances in the changes in ratings of AIMS scores between the diabinese group and the placebo group. Application of oral hypoglycemic agent might be a way of improving abnormal involuntary movements in schizophrenics with abnormal involuntary movements or TD. Althogugh it was not certain that there were correlations of abnormal involuntary movement with blood sugar and lipids, correlations of TC/TG with AIMS, of FBS with AIMS cautiously suggest that the regular check of $HbA_1C$, waist, and weight are recommended for schizophrenics.

• 산업경영시스템학회지
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• 제20권44호
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• pp.69-79
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• 1997

We investigate both of central and dispersion tendencies of the observed test statistics in control charts in order to judge whether a production process is abnormal or not. In order to do it, first, we study about detection of changes of the population mean as a central tendency The $\bar{x}$ and x control charts are used for detecting the change of the population mean $\mu$. We shows the probability detecting the change of population mean using the $\bar{x}$ and x control charts. Secondly, we study about detection of changes of the population standard deviation as a dispersion tendency in the s control chart. In our studies, for the given several parameters the detection probabilities of changes of central and dispersion tendencies are calculated, the necessary sample size values n are suggested for detecting the changes, and their informations are given as various tables.

• International journal of advanced smart convergence
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• 제9권4호
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• pp.8-15
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• 2020

This study was conducted in order to determine the effect of intraoperative hemoglobin changes on intraoperative neuromonitoring (IONM). This was a retrospective study that included 339 participants who underwent cerebrovascular surgery. We compared anesthetic agents, intraoperative hemoglobin, hematocrit, blood transfusion, and blood loss. We examined motor evoked potential and sensory evoked potential to patients. There were significant differences in hemoglobin changes, bleeding levels, transfusion, anesthesia time, and postoperative mobility disorders. Moreover, compared with patients who received transfusions, those who did not receive transfusion had a lower average hemoglobin level, as well as a higher bleeding amount, and a need of higher anesthesia time and anesthetic dose. Also, we found vasospasm occurred while surgery can bring adverse results after operation. This study showed that an intraoperative decrease in hemoglobin levels affects the function of cerebral perfusion, which could result in abnormal nerve monitoring results. However, as this study could not find a relation of anesthetics to IONM, there is a need for further research regarding the association between anesthetics and hemoglobin changes and IONM.