• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.84-84
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• 2022

The limit of crop cultivation is moving northward due to the temperature rise by climate change. There is a problem with crop growth if early sowing is performed at a time when the temperature is low. It is difficult to secure crop productivity and cultivation stability due to the low temperature and short cultivation period. Therefore, this study was conducted to analyze the change in growth characteristics and yield of corn for grain when early sowing is performed in central region of South Korea. This experiment was conducted at experimental field of Suwon in 2021. Three varieties of corn for grain such as Kwangpyeongok, Sinhwangok, and Hwangdaok were sown at intervals of 5 days from 20 March to 15 April. The planting density at this time was sown with a row interval of 70 cm and a plant interval of 25 cm. Nitrogen, phosphoric acid, and potassium fertilizers were applied at 17.4 kg, 3.0 kg, and 6.9 kg per 10a, respectively. Phosphoric acid and potassium fertilizers were all applied before sowing and nitrogen fertilizer was applied 50% before sowing and 50% in the fifth leaf period. The corn growth characteristics and yield components were investigated. The seedling establishment rate by sowing date was in the range of 68.5~88.5%, and it showed a difference depending on the variety. The range of days from sowing to tassel and silk emergence by sowing date was 79.9~98.4 and 81.0~98.9 days, respectively. As the sowing date was delayed, the days from sowing to tassel and silk emergence decreased. The growth characteristics and yield of corn by sowing date are as follows. Plant height was the highest at 241.3 cm at the sowing on 25 March, and Stalk diameter was the thickest at 25.6 mm at the sowing on 31 March. The fresh weight per plant was the highest at 728 g at the sowing on 25 March, and the dry weight per plant was the highest at 185 g at the sowing on 31 March. Corn growth characteristics did not show a certain trend depending on the sowing date, and corn growth was more vigorous at the sowing on March 25 and 31 than the others. In the case of ear weight, it was the heaviest with 344 g at the sowing on 25 March, and filled ear length ratio showed a tendency to decrease as the sowing time was delayed. The weight of 100 grains and grain yield per 10a of maize were the highest at 36.0g and 878.7kg/10a, respectively at the sowing on 25 March. Although the growth and yield of corn for grain were good during early sowing in the central region of South Korea, it is necessary to investigate the limit temperature for early sowing of corn by examining the annual variation according to weather conditions.

• Journal of Periodontal and Implant Science
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• 제54권1호
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• pp.53-62
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• 2024

Purpose: This study aimed to evaluate the long-term cumulative survival rate (CSR) of dental implants with micro-threads in the neck over a 10-year follow-up period and to examine the factors influencing the survival rate of dental implants. Methods: This retrospective study was based on radiographic and dental records. In total, 151 patients received 490 Oneplant^® dental implants with an implant neck micro-thread design during 2006-2010 in the Department of Periodontology of Seoul National University Dental Hospital. Implant survival was evaluated using Kaplan-Meier analysis. Cox proportional hazard regression analysis was used to identify the factors influencing implant failure. Results: Ten out of 490 implants (2.04%) failed due to fixture fracture. The CSR of the implants was 97.9%, and no significant difference was observed in the CSR between external-and internal-implant types (98.2% and 97.6%, respectively, P=0.670). In Cox regression analysis, 2-stage surgery significantly increased the risk of implant failure (hazard ratio: 4.769, P=0.039). There were no significant differences in influencing factors, including sex, age, implant diameter, length, fixture type, location, surgical procedure, bone grafting, and restoration type. Conclusions: Within the limitations of this retrospective study, the micro-thread design of the implant neck was found to be favorable for implant survival, with stable clinical outcomes.

• 대한영상의학회지
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• 제82권3호
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• pp.613-623
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• 2021

목적 내측 상과염 환자들 중 최종적으로 수술적 치료를 받게 된 환자들의 임상 및 자기공명영상 인자들의 특징을 알아보고자 한다. 대상과 방법 2010년 3월부터 2018년 12월까지 내측 상과염으로 진단받은 환자들 중에서 주관절 자기공명영상을 촬영한 52명의 환자들을 역행적으로 조사하였다. 환자들의 인구통계학적 및 임상적 정보, 자기공명영상 소견들이 평가되었다. 모든 변수들은 보존적인 치료를 받은 환자군과 수술적 치료를 받은 환자군 사이에서 비교되었고, 로지스틱 회귀분석을 통해 어떤 인자가 수술적 치료를 받은 환자군과 연관 있는지 분석하였다. 결과 횡단면 및 관상면 공통 굴곡근 건의 파열 크기(p < 0.001, p = 0.013), 횡단면 및 관상면 공통 굴곡근 건의 이상 정도(p = 0.022, p = 0.003)가 유의미한 차이를 보였다. 또한 내측 측부 인대의 이상 정도(p = 0.025) 또한 유의미한 차이를 보였다. 로지스틱 회귀분석에서는 오직 공통 굴곡근 건의 횡단면 파열 크기(오즈비: 1.864; 95% 신뢰구간: 1.264~2.750)가 수술적 치료와 관련이 있었다. 결론 내측 상과염으로 진단받은 환자들 중, 더 큰 횡단면 공통 굴곡근 건 파열을 동반한 환자들이 결과적으로 수술을 받게 되는 경향성이 보였다.

• 대한영상의학회지
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• 제84권6호
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• pp.1350-1360
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• 2023

목적 악성 담관 폐쇄 환자에서 경피경간 담도 배액술을 시행할 때 유증상 이탈을 유발하는 예측 인자에 대해 연구를 진행하고자 한다. 대상과 방법 2010년 1월부터 2015년 2월까지 572명의 악성 담관 폐쇄 환자에서 시행한 733건의 경피경간 담도 배액술을 대상으로 후향적 연구를 시행하였다. 카테터의 거치 기간, 접근 위치, 카테터 팁의 위치, 삽입 각도, 피그테일 루프의 유무, 도관 직경을 평가하였다. 결과 추적관찰 기간 동안 157명의 환자에서 224건(30.56%)의 도관 이탈이 발생하였다. 그중 146건(19.92%)가 유증상 도관 이탈이었다. 배액관 이탈 발생까지의 기간은 평균 30일(범위: 1-159일)이었다. 유증상 도관 이탈은 배액관의 교체(137명) 또는 담관 스텐트 삽입(9명)을 통해 치료하였다. 남성(교차비: 1.636, 95% 신뢰구간: 1.131-2.367, p = 0.009), 우측 접근(교차비: 1.567, 95% 신뢰구간: 1.080-2.274, p = 0.018), 도관 삽입 각도 증가(교차비: 1.015, 95% 신뢰구간: 1.005-1.026, p = 0.005), 불완전 피그테일 루프(교차비: 1.672, 95% 신뢰구간: 1.098-2.545, p = 0.016)가 독립적인 경피경간 담도 배액술 도관 유증상 이탈의 예측 인자였다. 결론 유증상 이탈을 유발하는 예측인자에는 남성, 우측 접근, 도관 삽입 각도 증가, 불완전 피그테일 루프가 있다.

• 한국산림과학회지
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• 제113권1호
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• pp.131-142
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• 2024

본 연구는 편백림의 생산목표 달성을 위한 생육단계별 적정 임분밀도관리 기준을 추정하고, 이로부터 솎아베기 적정 시업체계를 개발하는데 그 목적을 두고 있다. 모집된 편백림 216개 표본점을 대상으로 임내 세장목 점유율과 임분밀도 간의 관계특성을 분석하여 임분밀도 관리기준 지표로서 제시된 상대수확량지수는 Ry 0.75로 나타났다. 이로부터 기존 편백 시업체계의 생산목표별 타당성 검정을 실시한 결과, 임령 증가에 따른 솎아베기 강도의 불균형과 지위에 따른 생장속도가 반영되지 못하는 문제점이 있었다. 본 연구를 통해 작성된 생산목표별 솎아베기 시업체계에서, 대경재는 ha당 353본, 498.1 m³・ha-¹ 수확 가능하였으며, 중경재는 703본・ha-¹, 376.2 m³・ha-¹, 소경재는 1,758본・ha-¹, 249.5 m³・ha-¹으로 나타났다. 이상의 결과로부터 작성된 시업체계는 다양한 경영 목표에 따라 일률적으로 적용할 수는 없으나, 우리나라 편백림의 생장특성을 반영한 임분밀도관리도로부터 획득된 결과로서 실증적 참조 기준을 제시하는데 본 연구의 의의가 있다.

• Korean Journal of Radiology
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• 제22권10호
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• pp.1640-1649
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• 2021

Objective: Flattening in the anteroposterior direction (AP flattening) of the terminal ileum (TI) or sigmoid colon (SC) lying across the psoas muscle, on magnetic resonance enterography (MRE), might mimic bowel inflammation in the coronal view. This study investigated the prevalence of AP flattening and the factors associated with its development. Materials and Methods: A total of 364 surgery-naïve patients with Crohn's disease (CD) who had undergone MRE were retrospectively reviewed. AP flattening was defined as a luminal collapse in the anteroposterior direction, with a bowel width in the axial plane < 1/4 of the normal diameter without reduction of bowel width in coronal images. The prevalence of AP flattening of the TI and SC on MRE in patients with bowel segments lying across the psoas muscle was determined. We further compared the rate of AP flattening between MRE and computed tomography enterography (CTE) in a subcohort of patients with prior CTE. The factors associated with AP flattening were analyzed using multivariable logistic regression in a subcohort of patients with endoscopic findings of TI. Results: Three hundred and twenty-two and 363 patients, respectively, had TI and SC lying across the psoas muscle. The prevalence of AP flattening on MRE was 7.5% (24/322) in TI and 5.2% (19/363) in SC. The prevalences were significantly higher on MRE than on CTE in both the TI (7.3% [12/164] vs. 0.6% [1/164]; p = 0.003) and SC (5.8% [11/190] vs. 1.6% [3/190]; p = 0.039). AP flattening of the TI was independently and strongly associated with the absence of CD inflammation on endoscopy, with an adjusted odds ratio of 0.066 (p = 0.003) for the presence versus the absence (reference) of inflammation. Conclusion: AP flattening of the TI or SC lying across the psoas muscle was uncommon and predominantly observed on MRE of the bowel without CD inflammation.

• Korean Journal of Radiology
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• 제22권2호
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• pp.179-188
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• 2021

Objective: This study aimed to prospectively compare the efficacy, safety, and mid-term outcomes of dual-switching monopolar (DSM) radiofrequency ablation (RFA) to those of conventional single-switching monopolar (SSM) RFA in the treatment of hepatocellular carcinoma (HCC). Materials and Methods: This single-center, two-arm, parallel-group, randomized controlled study was approved by the Institutional Review Board. Written informed consent was obtained from all patients upon enrollment. A total of 80 patients with 94 HCC nodules were randomized into either the DSM-RFA group or SSM-RFA group in a 1:1 ratio, using a blocked randomization method (block size 2). The primary endpoint was the minimum diameter of the ablation zone per unit time. The secondary endpoints included other technical parameters, complication rate, technique efficacy, and 2-year clinical outcomes. Results: Significantly higher ablation energy per unit time was delivered to the DSM-RFA group than to the SSM-RFA group (1.7 ± 0.2 kcal/min vs. 1.2 ± 0.3 kcal/min; p < 0.001). However, no significant differences were observed between the two groups for the analyzed variables, including primary endpoint, regarding size of the ablation zone and ablation time. Major complication rates were 4.9% in the DSM-RFA group and 2.6% in the SSM-RFA group (p = 1.000). The 2-year local tumor progression (LTP) rates of the HCC nodules treated using DSM-RFA and SSM-RFA were 8.5% and 4.7%, respectively (p = 0.316). The 2-year LTP-free survival rates of patients in the DSM-RFA and SSM-RFA groups were 90.0% and 94.4%, respectively (p = 0.331), and the 2-year recurrence-free survival rates were 54.9% and 75.7%, respectively (p = 0.265). Conclusion: Although DSM-RFA using a separable clustered electrode delivers higher ablation energy than SSM-RFA, its effectiveness failed to show superiority over SSM-RFA in the treatment of HCC.

• 한국환경복원기술학회지
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• 제27권3호
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• pp.1-18
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• 2024

The study aims to establish a direction for forest ecological restoration by classifying forest types and understanding the ecological characteristics of the Uljin forest area damaged by a large fire in 2022. Hierarchical cluster analysis and indicator species analysis were conducted on 78 survey plots located in the forest fire-affected area, and four forest cover types were derived: P. densiflora pure forests, P. densiflora dominant forests, mixed broad-leaved forests, and Q. variabilis dominant forests. As a result of visually comparing changes in forest types before and after forest fire damage, by classifying data according to whether or not upper dead trees are included, it was confirmed that pine forests, which have a high proportion of pine trees, spread widely due to forest fire damage. However, broad-leaved mixed forests and oyster oak dominant forests showed characteristics of maintaining concentration, indicating that pine forests were severely damaged. As a result of the important value analysis, during the process of natural recovery after a forest fire, the species that appear early in the lower layer are the sprouts of existing species such as Quercus mongolica Fisch. ex Ledeb., Quercus variabilis Blume, Fraxinus sieboldiana Blume, Rhododendron mucronulatum Turcz. The distribution of diameter at breast height by forest cover type showed that among areas with extreme forest fire damage, the proportion of dead trees was relatively high and structural changes were large in P. densiflora pure forests and P. densiflora dominant forests where pine trees had a high distribution ratio. However, if continuous monitoring is carried out in the future with reference to the results of this study and plant data is collected and analyzed from a mid- to long-term perspective, it is believed that it will be used as useful data to promote forest ecological restoration projects in forest fire-affected areas.

• Korean Journal of Radiology
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• 제20권5호
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• pp.854-861
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• 2019

Objective: To evaluate quantitative magnetic resonance imaging (MRI) parameters for differentiation of cysts from and solid masses in the anterior mediastinum. Materials and Methods: The development dataset included 18 patients from two institutions with pathologically-proven cysts (n = 6) and solid masses (n = 12) in the anterior mediastinum. We measured the maximum diameter, normalized T1 and T2 signal intensity (nT1 and nT2), normalized apparent diffusion coefficient (nADC), and relative enhancement ratio (RER) of each lesion. RERs were obtained by non-rigid registration and subtraction of precontrast and postcontrast T1-weighted images. Differentiation criteria between cysts and solid masses were identified based on receiver operating characteristics analysis. For validation, two separate datasets were utilized: 15 patients with 8 cysts and 7 solid masses from another institution (validation dataset 1); and 11 patients with clinically diagnosed cysts stable for more than two years (validation dataset 2). Sensitivity and specificity were calculated from the validation datasets. Results: nT2, nADC, and RER significantly differed between cysts and solid masses (p = 0.032, 0.013, and < 0.001, respectively). The following criteria differentiated cysts from solid masses: RER < 26.1%; nADC > 0.63; nT2 > 0.39. In validation dataset 1, the sensitivity of the RER, nADC, and nT2 criteria was 87.5%, 100%, and 75.0%, and the specificity was 100%, 40.0%, and 57.4%, respectively. In validation dataset 2, the sensitivity of the RER, nADC, and nT2 criteria was 90.9%, 90.9%, and 72.7%, respectively. Conclusion: Quantitative MRI criteria using nT2, nADC, and particularly RER can assist differentiation of cysts from solid masses in the anterior mediastinum.

• 한국산림과학회지
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• 제32권1호
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• pp.36-63
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• 1976

1974년(年) 천연(天然)소나무집단(集團)에 대한 유전적변이(遺傳的變異)를 분석(分析)하고져 먼저 경북(慶北) 청송군(靑松郡) 소재(所在) 주왕산(周王山)소나무림(林), 충남(忠南) 서산군(瑞山郡) 소재(所在) 안면도(安眠島) 소나무림(林), 그리고 강원도(江原道) 평창군(平昌郡) 소재(所在) 소나무림(林)을 대상(對象)으로하여 각(各) 집단(集團)에서 되도록 소면적(小面積)의 범위내(範圍內)에 서있는 소나무 개체(個體)를 각(各) 20주(株)씩 총 60주(株)를 택(擇)하여 그 모수(母樹)에 대한 형태학적(形態學的) 특성(特性)등을 조사측정(調査測定)하고 집단간(集團間)에 보이는 차이(差異) 그리고 한 집단내(集團內)에 있는 각개체수목(各個體樹木)의 형질(形質)을 조사보고(調査報告)한바 있다(제일보고문(第一報論文). 1974년(年) 가을에 가계별(家系別)로 종자(種字)을 채취(採取)하여서 가계별(家系別) 및 산지별(産地別)의 차이(差異)를 분석(分析)하고 동시(同時)에 그 종자(種字)를 파종하여서 1-0묘(苗) 및 1-1묘(苗)를 대상(對象)으로 생장인자(生長因子)에 대한 측정(測定)을 하고 그 유전력(遺傳力)을 계산(計算)해 보았다. 그밖에 엽록소함량(葉綠素含量) 또는 monoterpene등의 함량(含量)의 차이(差異)를 분석(分析)해 보았다. 종자(種字)의 형태학적(形態學的) 특성(特性)에 있어서는 집단간(集團間) 또 가계간(家系間)에 유의차(有意差)를 보이지 않는 것도 있었으나 대체(大體)로 유의차(有意差)가 인정(認定)되었다. 그리고 각형질간(各形質間)의 상관(相關)을 보았는데 구과폭(毬果幅)과 종자익(種字翼)의 폭(幅), 구과장(毬果長)과 종자익(種字翼)의 길이간(間), 그리고 구과(毬果) 생중량(生重量)과 종자중량간(種字重量間)에는 정(正)의 상관(相關)이 보였다. 묘고(苗高)와 근원경(根元徑)의 성장(成長)에 있어서는 가계간(家系間) 그리고 집단간(集團間)에 차이(差異)가 인정되었다. 묘고(苗高)의 유전력(遺傳力)은 집단(集團)의 평균치(平均値)를 가지고 분석(分析)하였다. 즉 집단(集團)에 관계(關係)되는 분산(分散)을 유전분산(遺傳分散)으로 보고서 유전력(遺傳力)을 계산(計算)해 보았는데 1-0묘(苗)의 묘고(苗高)에서는 0.29, 1-1묘(苗)에서는 0.14가 그리고 근원경(根元徑)에 있어서는 1-0묘(苗)는 0.15, 1-1묘(苗)에서는 0.06이였다. 기공열수(氣孔列數)에 있어서는 집단간차이(集團間差異)가 있었으나 거치밀도(鋸齒密度)에는 차이(差異)가 없었다. 침엽(針葉)의 특성(特性)에 관(關)해서는 모수(母樹)와 차대간(次代間)에 상관(相關)이 없었다. 엽록소함량(葉綠素含量)은 집단간차이(集團間差異)는 보였으나 가계간차이(家系間差異)는 없었다. monoterpene의 성분(成分)에 있어서는 myrcene과 ${\beta}$-phellandrene의 함량(含量)으로 집단차(集團差)를 볼 수 있었다.