• Journal of Ginseng Research
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• 제44권1호
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• pp.44-49
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• 2020

Background: Salting-out extraction (SOE) had been developed as a special branch of aqueous two-phase system recently. So far as we know, few reports involved in extracting ginsenosides with SOE because of the lower recovery caused by the unique solubility and surface activity of ginsenosides. A new SOE method for rapid pretreatment of ginsenosides from the enzymatic hydrolysates of Panax quinquefolium was established in this article. Methods: The SOE system comprising ethanol and sodium carbonate was selected to extract ginsenosides from the enzymatic hydrolysates of Panax quinquefolium, and HPLC was applied to analyze the ginsenosides. Results: The optimized extraction conditions were as follows: the aqueous two-phase extraction system comprising ethanol, sodium carbonate, ethanol concentration of 41.51%, and the mass percent of sodium carbonate of 7.9% in the extraction system under the experimental condition. Extraction time had minor influence on extraction efficiency of ginsenosides. The results also showed that the extraction efficiencies of three ginsenosides were all more than 90.0% only in a single step. Conclusion: The proposed method had been successfully applied to determine ginsenosides in enzymatic hydrolysate and demonstrated as a powerful technique for separating and purifying ginsenosides in complex samples.

• 자원리싸이클링
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• 제26권1호
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• pp.37-42
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• 2017

이산화탄소 저감을 위한 유효한 방법 중의 하나로 칼슘규산염 광물의 간접탄산염화 공정이 보고되고 있다. 이 공정은 염산, 질산 등의 산에 의하여 칼슘규산염으로부터 칼슘성분을 침출하는 단계와 이산화탄소에 의한 침출용액의 탄산염화 단계의 두 과정으로 구성된다. 침출용매로 초산수용액을 사용하는 경우에는 침출용액을 이산화탄소로 탄산염화 하는 과정에서 초산이 재생성 되어 침출단계로 순환되어 침출용매로 재사용될 수 있다. 제철 및 제강슬래그와 같은 산업부산물은 칼슘규산염을 많이 함유하고 있어 간접탄산염화공정의 원료로 사용될 수 있다. 본 연구에서는 초산수용액에 의한 국내 전기로제강슬래그의 침출효율을 조사하기 위하여, 초산수용액 농도, 침출온도 및 침출시간 등의 침출조건 변화에 따른 침출실험을 수행하였다.

• 대한치과교정학회지
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• 제49권4호
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• pp.222-234
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• 2019

Objective: To investigate the three-dimensional lip vermilion changes after extraction and non-extraction orthodontic treatment in female adult patients and explore the correlation between lip vermilion changes and incisor changes. Methods: Forty-seven young female adult patients were enrolled in this study (skeletal Class III patients were excluded), including 34 lip-protruding patients treated by extraction of four first premolars (18 patients requiring mini-implants for maximum anchorage control and 16 patients without mini-implants) and 13 patients requiring non-extraction treatment. Nine angles, seven distances, and the surface area of the lip vermilion were measured by using pre- and post-treatment three-dimensional facial scans. Linear and angular measurements of incisors were performed on lateral cephalograms. Results: There were no significant changes in the vermilion measurements in the non-extraction group. The vermilion angle, vermilion height, central bow angle, height/width ratio, and vermilion surface area decreased significantly after the orthodontic treatment in the extraction groups, but the upper/lower vermilion proportion remained unchanged. Significant correlations were found between the changes in incisor position and those in vermilion angles, vermilion height, and surface area. Conclusions: Extraction of the four first premolars probably produced an aesthetic improvement in lip vermilion morphology. However, the upper/lower vermilion proportion remained unchanged. The variations in the vermilion were closely related to incisor changes, especially the upper incisor inclination changes.

• Journal of Periodontal and Implant Science
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• 제51권4호
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• pp.285-295
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• 2021

Purpose: The aims of the present study were 1) to quantitatively evaluate the extent of sinus pneumatization and 2) to determine the factors affecting sinus pneumatization. Methods: Based on implant treatment records, a list of patients who underwent implant placement on the posterior maxilla was obtained. Among them, patients with pre-extraction and post-extraction (before implant placement) panoramic radiographs were selected. After excluding radiographs with low resolution and image distortion, the radiographs before and after extraction were superimposed using computer software. Subsequently, the extent of sinus pneumatization (the vertical change of the sinus floor) was measured. Simple and multiple mixed models were used to determine the factors affecting sinus pneumatization. Results: A total of 145 patients were eligible for the present investigation. The average extent of sinus pneumatization was 1.56±3.93 mm at 176 tooth sites. Male sex, single tooth extraction, extraction of an endodontically compromised tooth, a class I root-sinus relationship, and sinus membrane thickening >10 mm favored pneumatization, but without statistical significance. The maxillary second molar presented the greatest pneumatization (2.25±4.39 mm) compared with other tooth types. This finding was confirmed in the multiple mixed model, which demonstrated a statistically significant impact of the extraction of a second molar compared with the extraction of a first premolar. Conclusions: Maxillary sinus pneumatization was 1.56±3.93 mm on average. The extraction of a second molar led to the greatest extent of pneumatization, which should be considered in the treatment plan for this tooth site.

• Journal of Dental Anesthesia and Pain Medicine
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• 제22권5호
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• pp.387-394
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• 2022

Background: Dental pain management is an important aspect of patient management in pediatric dentistry. Articaine is considered the most successful anesthetic agent for infiltration anesthesia. Buffered articaine has been observed to have faster onset and longer duration of action with less pain on injection. The aim of this study was to evaluate and compare pain on injection, onset of action, and pain during extraction using buffered (using Sodium bicarbonate (NaHCO₃)) and non-buffered 4% articaine (with 1:100000 adrenaline) infiltrations for primary maxillary molar extractions in 4-10-year-old children. Methods: Seventy children who required extraction of maxillary primary molars were enrolled in this triple-blind randomized study. Children undergoing extraction were randomly divided into two groups, with 35 in each group. The study group was the buffered articaine group; the control group was the non-buffered articaine group. Buccal and palatal infiltrations were administered with either buffered or non-buffered articaine. Subjective evaluation was done for pain on injection, pain during extraction using Wong-Baker Faces Pain Rating Scale (WBFPR) and onset of anesthesia in seconds. Pain on injection, pain during extraction were objectively evaluated using Sound Eye Motor (SEM) scale and onset of anesthesia was also evaluated objectively by pricking with sharp dental probe. Results: The outcome was, significantly less pain on injection and significantly faster onset of anesthesia with significantly less pain during extraction for both subjective and objective evaluations in the buffered articaine group. Subgroup analysis was also performed and it showed variable results, with only significant difference for WBFPR scores in age subgroup 4-7 years for palatal infiltration. Conclusion: Less pain on injection, faster onset of anesthesia, and less pain during extraction were observed when buffered articaine was used for maxillary primary molar extraction.

• 한국정보통신학회논문지
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• 제19권4호
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• pp.948-953
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• 2015

최근, 생체 정보를 이용하여 개인의 신원을 확인하기 위해 근적외선 LED와 CCD 카메라를 이용한 지정맥 인식기술 연구되고 있다. 지정맥 인식은 손가락의 두께, 주변 광, 체온카메라 등의 잡음으로부터 정맥과 배경 이미지를 분리하는 방법에 따라 성능의 차이가 발생한다. 이러한 문제점을 개선하기 위해 본 연구에서는 NIR LED와 CCD 카메라로 촬영된 지정맥 영상으로부터 지정맥 회전, ROI 검출, 필터뱅크를 이용한 정맥 증강 기법을 제안하고 실험을 통하여 그 성능을 평가하였다. 이 실험의 결과에서 제안된 지정맥 회전과 ROI 검출의 정확도가 99.8%를 보였다. 그리고 필터뱅크를 이용한 정맥 증강처리에서는 제안된 방법이Retinex 알고리즘 보다 우수한 대비 성능을 보였다. 이 실험의 결과로부터 제안된 방법을 정맥인식의 전처리 과정에 적용한다면, 보다 나은 인식률을 제공할 것으로 사료된다.

• 정보과학회 논문지
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• 제42권6호
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• pp.817-822
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• 2015

관계 추출은 질의응답 및 지식확장 등에 널리 사용될 수 있는 주요 정보추출 기술이다. 정보추출에 관한 기존 연구들은 관계 범주가 수동으로 부착된 대용량의 학습 데이터를 필요로 하는 지도 학습모델을 기반으로 이루어져 왔다. 최근에는 학습 데이터 구축을 위한 인간의 노력을 줄이기 위해 원거리 감독법이 제안되었다. 그러나 원거리 감독법은 분류 문제를 해결하는데 필수적인 부정 학습 데이터를 수집하기 어렵다는 단점이 있다. 이러한 원거리 감독법의 단점을 극복하기 위해 본 논문에서는 부정 데이터 없이 학습이 가능한 단일 클래스 분류 모델을 제안한다. 입력 데이터로부터 긍정 데이터를 선별하기 위해서 제안 모델은 벡터 공간 상에서 어휘 정보와 구문 패턴에 기반한 유사도 척도를 사용하여 입력 데이터가 내부 범주에 속하는지 그렇지 않은지 판단한다. 실험에서 제안 모델은 대표적인 단일 클래스 분류 모델인 One-class SVM보다 높은 성능(0.6509 F1-점수, 0.6833 정밀도)을 보였다.

• 정보과학회 논문지
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• 제44권11호
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• pp.1138-1148
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• 2017

토픽 추출은 문서 집합으로부터 그 문서 집합을 대표하는 토픽을 자동 추출하는 기술이며 자연어 처리의 중요한 연구 분야이다. 대표적인 토픽 추출 방법으로는 잠재 디리클레 할당과 단어 군집화 기반 토픽 추출방법이 있다. 그러나 이러한 방법의 문제점으로는 토픽 중복 문제와 토픽 혼재 문제가 있다. 토픽 중복 문제는 특정 토픽이 여러 개의 토픽으로 추출되는 문제이며, 토픽 혼재 문제는 추출된 하나의 토픽 내에 여러 토픽이 혼재되어 있는 문제이다. 이러한 문제를 해결하기 위하여 본 연구에서는 토픽 중복 문제에 대해 강건한 잠재 디리클레 할당으로 토픽을 추출하고 단어 간 유사도를 이용하여 토픽 분리 및 토픽 병합의 단계를 거쳐 최종적으로 토픽을 보정하는 방법을 제안한다. 실험 결과 제안 방법이 잠재 디리클레 할당 방법에 비해 좋은 성능을 보였다.

• 한국환경농학회지
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• 제39권1호
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• pp.44-49
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• 2020

BACKGROUND: Benzo(a)pyrene is a highly toxic substance which has been listed as a Group I carcinogen by the International Agency for Research on Cancer. There have been numerous studies by researchers worldwide on benzo(a)pyrene. Soxhlet, ultrasound-assisted, and liquid-liquid extractions have been widely used for the analysis of benzo(a)pyrene. However these extraction methods have significant drawbacks, such as long extraction time and large amount of solvent usage. To overcome these disadvantages, we aimed to establish a rapid residual analysis of benzo(a)pyrene content in agricultural products and soil samples. METHODS AND RESULTS: A Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was used as the pretreatment procedure. For rapid residual analysis of benzo(a)pyrene, a modified QuEChERS method were used, and the best codition was demonstrated after various performing instrument analysis. The extraction efficiency of this method was also compared with Soxhlet extraction, the current benzo(a)pyrene extracting method. Although both methods showed high recovery rates, the rapid residual analysis method markedly reduced both the measurement time and solvent usage by approximately 97% and 96%, respectively. CONCLUSION: Based on these results, we suggest the rapid residual analysis method established through this study, faster and more efficient analysis of residual benzo(a)pyrene in major agricultural products such as rice, green and red chili peppers and also soil samples.

• 한국물환경학회지
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• 제22권5호
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• pp.879-886
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• 2006

The analytical methods of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) for water sample with extremely low concentration was developed to extract large volume and to improve fast chromatography for clean up. Semi-automated solid phase extraction (SPE) system and column coupling chromatography using elution pump was optimized and applied to each processes of treatment plant. Results of disk type SPE indicated that this system was applicable below 40 L of aqueous sample with a flow rate of 0.08 ~ 0.2 L/min. Average recoveries of SPE using labeled sampling spike of $^{37}Cl$-2,3,7,8-TCDD was 97%. Column coupling method resulted in reduced clean up time, solvent volume, increased average recoveries with constant elution rate. The combined methods were applied to the monitoring of drinking water treatment plant. Limits of detection (LOD) of each process were calculated. For example, LOD of raw and treated water ranged 0.094~0.968 pg/L and 0.028~0.364 pg/L, respectively. Combined methods of extraction and cleanup techniques provided fast analysis of PCDD/Fs with high accuracy and low LODs for water samples.