• 대한임상독성학회지
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• 제16권2호
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• pp.93-101
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• 2018

Purpose: The Korean government has tried to decrease the suicide death rate over the last decade. Suicide attempts, particularly non-fatal attempts, are the most powerful known risk factor for a completed suicide. An analysis of suicide attempt methods will help establish the effective preventive action of suicide. Fit prevention according to the method of suicide attempt may decrease the incidence of suicide death. Self-poisoning is suggested as a major method of both suicide attempts and suicide death. The aim of this study was to determine if a self-poisoning patient is a suitable target for the prevention of the suicide. Methods: This was retrospective analysis of a prospective cohort, which included patients who presented to the emergency department (ED) after a self-harm or suicide attempt from Jan 2013 to Dec 2017. The proportion of methods in suicide attempts, psychological consultation, and fatality according to the suicide attempt method were analyzed. The types of poison were also analyzed. Results: Poisoning was the most common method of suicide attempts (52.1%). The rate of psychological consultations were 18.8% for all patients and 29.1% for poison patients (p<0.001). The rate of mortality in poisoning was 0.6%. Psychological consultation was performed more frequently in admission cases than discharged cases. The most common materials of poisons was psychological medicines and sedatives that had been prescribed at clinics or hospital. Conclusion: Self-poisoning is a major method of suicide attempt with a high rate of psychiatric consultation, low mortality rate, versus others methods. The prevention of suicide death for suicide attempts may focus on self-poisoning, which is the major method of suicide attempts. A suitable aftercare program for self-poisoning may be an effective method for preventing suicide if an early diagnosis and management of psychiatric disorders through psychiatric consultation can be made, and early connection to social prevention program for non-fatal patients are possible.

• 대한간학회지
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• 제24권4호
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• pp.374-383
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• 2018

Background/Aims: There have been numerous efforts to reduce mother-to-child transmission (MTCT) of hepatitis B virus (HBV) with antiviral agents during pregnancy. However, there are limited data regarding the outcomes of pregnant women after delivery. This study was performed to evaluate the efficacy of antiviral agents in preventing MTCT of HBV and maternal long-term outcomes. Methods: The HBV-infected pregnant women treated with antiviral agents to prevent MTCT were retrospectively reviewed. Forty-one pregnant women who received telbivudine or tenofovir during late pregnancy (28-34 week) were analyzed. Hepatitis B virus surface antibody (HBsAb) positivity was tested in 43 infants after 7 months of birth. Eleven mothers were followed >1 year after delivery. Results: The mean HBV DNA titer before antiviral therapy was 8.67 (6.60-9.49) log copies/mL, and the median age at delivery was 32 years (range, 22-40). Eleven patients were treated with tenofovir and 30 with telbivudine. The median duration was 57 days (range, 23-100), and the median HBV DNA titer at birth was 5.06 log copies/mL (range, 2.06-6.50). Antiviral treatments were associated with significant HBV DNA reduction (P<0.001). Among 43 infants (two cases of twins), HBsAb was not detected in two, subsequently confirmed to have HBV infection. Biochemical flare was observed in two of 11 mothers followed >12 months, and an antiviral agent was administered. Conclusions: Antiviral treatment during late pregnancy effectively reduced MTCT. Long-term follow-up should be required in such cases. In addition, given that maternal biochemical flare occurred in 18% of mothers, re-administration of antiviral agents might be required.

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.135-141
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• 2020

실리카-벤젠 에어로겔은 균일하고 정렬된 네트워크 기공 구조, 개선된 기계적 특성을 갖도록 합성되었다. 실리카 에어로겔의 기계적 특성을 향상시키기 위해 유기물을 첨가하는 것이 일반적인 방법이지만, 기공 특성이 유-무기 상분리 현상으로 인해 감소한다. 본 연구에서는 실리카 기반 에어로겔의 기공 특성을 유지하면서 동시에 기계적 물성을 높이기 위해 간단하고 저렴한 방법을 사용하였다. 기공 및 기계적 특성에 대한 하이드록실 결합수의 영향을 연구하기 위해 두 가지 유형의 벤젠 브리지 전구체를 사용하였다. 다공성 실리카 에어로겔은 간단하고 비용-효율적이며 무공해인 졸-겔방법으로 제조되었다. 최종적으로 제조된 실리카-벤젠 에어로겔은 추가적인 silylating reagents없이 우수한 기공 특성, 높은 비 표면적(1,326 ㎡/g), 다공성 구조 및 소수성(>140°)을 가졌다. 일부 샘플(2T4)의 경우 기계적 강도는 순수 실리카 에어로겔의 5 배 이상을 보였다.

• 한국환경복원기술학회지
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• 제23권6호
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• pp.109-123
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• 2020

The purpose of this study is to provide basic data for the establishment of future countermeasures by diagnosing the growth status and actual condition of undesignated old trees distributed in Hyeongok-myeon, Gyeongju, Gyeongsangbuk-do. The number of old trees surveyed was 2 weeks in Gajeong-ri, 2 weeks in Haguri, 3 weeks in Nae-Tae-ri, 1 week in Nawon-ri, 6 weeks in Oryu-ri, 3 weeks in Sangguri, and 2 weeks in Sohyeon-ri, The trees species composition was 6 trees Celtis sinensis Pers., 1 Diospyros lotus L. trees, 4 trees Salix chaenomeloides Kimura trees, 2 Styphnolobium japonicum L. trees, and 7 Zelkova serrata (Thunb.) Makino trees. Growth status is 7.1~22.0m in height, 14.6~25.1m in long axis, 10.2~19.2m in short axis, root diameter is 76.0~236.4cm, diamter at breast height is 67.0~220.0cm, soil acidity is pH4.9~7.0, soil The hardness was measured to be 4.0-27.0mm. The result grade of the scoring data of health information is represented by monitoring generally, monitoring critically, and absolute monitoring, and it was confirmed that out of the 20 trees population in Hyeongok-myeon, the general monitoring grade was 7 weeks, the major monitoring grade was 13 weeks, and there was no absolute monitoring grade. Accordingly, the number of old trees of the general surveillance level was maintained at the current level, and ecological surgical operations were introduced for the major surveillance level, but the case of village forests should be different, and sequential treatments were the old tree urgently needed. The level and bark of the target tree, the state of the crown, the root exposure, the presence of pests and pests, the vitality and the ground condition, the degree of pollution are normal, poor, or very poor, operation and protection management, soil improvement, removal of cover, and disinfection were urgently needed for the old trees with the surveyed data. In order to compensate for these matters, continuous monitoring and management measures for the old number should be sought.

• 한국수산과학회지
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• 제55권6호
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• pp.827-835
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• 2022

Commercial boiled frozen ark shell Scapharca subcrenata (BFAS) is generally used as a seasoned seafood products. One problem facing the industry is that quality decreases during thawing. This study investigated ways to improve quality and shelf-stability of BFAS for use as a non-thermally prepared seasoned seafood products. The Viable bacteria were detected in BFAS after thawing under running water, but were not detected after blanching for over 2 min at 95±5℃. Blanching and dewatering times were optimized by response surface methodology (RSM) to reduce the initial number of bacteria and improve BFAS texture. Experimental design was deemed appropriate because no significant difference (P>0.05) was observed between predicted and actual moisture content, hardness, and overall acceptance values. Optimal blanching and dewatering times were 210 s and 80 s, respectively. Optimized blanching and dewatering processes can significantly improve safety and BAFS qualities including texture. These results indicate that BFAS demand as a staple for home meal replacements can be increased by application of optimized blanching and dewatering processes, especially in Korean seafood processing companies where running water thawing is common.

• 한국전기전자재료학회논문지
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• 제35권1호
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• pp.44-49
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• 2022

In this paper, we investigated current (I)- and voltage (V)-sweeping properties in a double-stack structure, Ge₂Sb₂Te₅/Ti/W-doped Ge₈Sb₂Te₁₁, a candidate medium for applications to multilevel phase-change memory. 200-nm-thick and W-doped Ge₂Sb₂Te₅ and W-doped Ge₈Sb₂Te₁₁ films were deposited on p-type Si(100) substrate using magnetron sputtering system, and the sheet resistance was measured using 4 point-probe method. The sheet resistance of amorphous-phase W-doped Ge₈Sb₂Te₁₁ film was about 1 order larger than that of Ge₂Sb₂Te₅ film. The I- and V-sweeping properties were measured using sourcemeter, pulse generator, and digital multimeter. The speed of amorphous-to-multilevel crystallization was evaluated from a graph of resistance vs. pulse duration (t) at a fixed applied voltage (12 V). All the double-stack cells exhibited a two-step phase change process with the multilevel memory states of high-middle-low resistance (HR-MR-LR). In particular, the stable MR state is required to guarantee the reliability of the multilevel phase-change memory. For the Ge₂Sb₂Te₅ (150 nm)/Ti (20 nm)/W-Ge₈Sb₂Te₁₁ (50 nm), the phase transformations of HR→MR and MR→LR were observed at t<30ns and t<65ns, respectively. We believe that a high speed and stable multilevel phase-change memory can be optimized by the double-stack structure of proper Ge-Sb-Te films separated by a barrier metal (Ti).

• 대한족부족관절학회지
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• 제27권2호
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• pp.49-54
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• 2023

Purpose: The present study examined the effectiveness of the preoperative ischemia-modified albumin (IMA) levels in predicting the healing period of amputation wounds in patients with diabetes mellitus following a non-traumatic below-knee amputation (BKA). Materials and Methods: This study enrolled 41 diabetic foot ulcer patients who underwent BKA at the authors' hospital diabetic foot center from April 2016 to April 2022. Among the 41 patients, 29 (70.7%) were male and 12 (29.3%) were female. Their mean age was 64.54±11.38 years (41~81 years). The mean follow-up period was 19.48±5.56 weeks (14~48 weeks) after BKA. The patients were divided into two groups (high IMA group and normal IMA group), which evaluated the healing period, wound dehiscence, and revision operation rate using a Fisher's exact test and Mann-Whitney U test. Three orthopedic surgeons performed stump wound evaluation, and they were evaluated as healing when all sutures were fused without oozing. Results: Thirty patients (73.2%) (group A) showed a high level of IMA (median: 91.2 U/mL), and 11 (26.8%) patients (group B) showed a normal range of IMA (median: 82.7 U/mL). In group A, the median period for wound healing took 1.4 weeks longer, which was significant (p=0.001). No statistical relationship was observed between wound dehiscence, revision operation rate, and IMA value. There was no correlation between the other risk factors (estimated glomerular filtration rate, HbA1c) and the wound healing period. Conclusion: Although there was a limitation in using IMA as the sole factor to predict the healing period of amputation wounds in patients after BKA, this study revealed a significant positive correlation between IMA and the period of stump healing after BKA. Therefore, the preoperative IMA levels may help predict the period of stump healing after BKA.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.30-30
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• 2020

본 연구에서는 여름철에 농업용수(벼농사용)로서 집중적으로 지하수를 사용하는 지역에서 시기별 지하수 사용에 따른 지하수 수질변화를 평가하기 위해 수행되었다. 연구지역은 충남 홍성군 양곡리와 신곡리 일부를 포함하는 면적 2.83 ㎢(283.3 ha)에 해당하는 지역이다. 연구지역 지하수 수질의 공간적 분포 및 시간적 변화 특성 평가를 위하여 2019년 2회(7월, 10월)에 걸쳐 지하수 관정(21개소)에 대하여 조사 및 분석을 수행하였다. 지하수 샘플은 현장에서 온도(T), pH, 용존산소(DO) 및 전기전도도(EC), 산화환원전위(Eh) 등을 측정하였고, 실험실에서 주요 양이온 및 미량원소(Ca, Mg, Na, K, Si, Sr), 음이온(F, Cl, Br, NO₂, NO₃, PO₄, SO₄), 알칼리도, 용존 유기탄소(DOC)와 용존 유기물(DOM) 등을 분석하였다. 지하수 수질조사 결과, 전체의 14~15개소(67~71%)가 Ca-HCO₃ 유형으로 분류되었으며, 다음으로는 Ca-Cl 유형이 4~5개소(19~24%)가 관찰되었다. 얕은 심도의 관정에서 상대적으로 심도가 깊은 관정보다 대부분 성분(TDS, Ca, Mg, Na, K, Cl, SO₄, HCO₃, DOC)에서 높은 농도를 나타내었다. 지하수의 수질자료를 이용하여 다변량통계분석법인 주성분분석(PCA: Principal Components Analysis)과 계층적 군집분석(HCA: Hierachical Cluster Anlaysis)를 수행한 결과, 초기 3개 주요 고유성분(eigenvalue)는 PC1 54.0%, PC2 14.2%, PC3 12.3%로 전체 분산의 88.3%를 설명할 수 있었다. PC1은 Ca, Mg, Na, K, Cl, SO₄, DOC가 주요한 영향 인자였으며 PC2는 HCO₃, NO₃, DO에 영향 받음을 확인하였다. 계층적 군집분석 결과, 연구지역 지하수는 Na-Cl 유형의 C-3 관정을 제외하고는 크게 두 그룹으로 구분되어 졌다. 다변량통계분석의 결과에서도 수리지화학, 동위원소, 용존유기물 등의 특성에서 나타나는 것과 유사한 연구지역의 수질특성을 확인할 수 있었다. 연구지역은 차시기 동안 수질변화는 일부 관정을 제외하고는 유의할 만한 수준으로 관찰되지는 않았고, 지하수 사용에 따른 지하수위 회복도 빠르게 진행되고 있는 것으로 나타났다.

• 한국환경보건학회지
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• 제49권5호
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• pp.251-261
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• 2023

Background: This paper deals with the study of natural radioactivity in rocks from Ogun State in Southwestern Nigeria. The aim is to determine radiation emissions from rocks in order to estimate radiation hazard indices. Objectives: The following objectives were targeted: 1. To determine radiation emissions from each type of rocks; 2. To estimate radiation hazard indices based on the rocks; 3. To correlate the activity concentrations of radionuclides with major oxides. Methods: The samples were analyzed using a NaI (Tl) gamma ray spectrometric detector and PerkinElmer AAnalyst 400 AAS spectrometer. Results: The activity of ⁴⁰K, ²²⁶Ra, and ²³²Th were found in order of decreasing magnitude from pegmatite>granite>migmatite. In contrast, lower concentrations were found in shale, phosphate, clay stone, sandstone and limestone. The mean absorbed doses were 125±23 nGyh^-1 (migmatite), 74±13 nGy/h (granite), 72±13 nGyh^-1 (pegmatite), 64±09 nGyh^-1 (quartzite), 45±16 nGyh^-1 (shale), 41±09 nGyh^-1 (limestone), 41±11 nGyh^-1 (clay stone), 24±03 nGyh^-1 (phosphate), and 21±10 nGyh^-1 (sandstone). The outdoor effective dose rates in all rock samples were slightly higher than the world average dose value of 0.34 mSvy^-1. The percentage composition of SiO₂ in the rock samples was above 50 wt% except for in the limestone, shale and phosphate. Al₂O₃ ranged from 4.10~21.24 wt%, Fe₂O₃ from 0.39~7.5 wt%, and CaO from 0.09-46.6 wt%. In addition, Na₂O and K₂O were present in at least 5 wt%. Other major oxides, including TiO₂, P₂O₅, K₂O, MnO, MgO and Na₂O were depleted. Conclusions: The findings suggest that Ogun State may be described as a region with elevated background radiation. It is recommended that houses should be constructed with good cross ventilation and residences should use home radiation monitoring instruments to monitor radon emanating from walls.

• 한국전기전자재료학회논문지
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• 제37권1호
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• pp.88-93
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• 2024

To evaluate the possibility as a multi-level memory medium for the Ge₂Sb₂Te₅/TiN/W-doped Ge₂Sb₂Te₅ cell structure, the crystallization rate and stabilization characteristics according to voltage (V)- and current (I)- pulse sweeping were investigated. In the cell structures prepared by a magnetron sputtering system on a p-type Si (100) substrate, the Ge₂Sb₂Te₅ and W-doped Ge₂Sb₂Te₅ thin films were separated by a barrier metal, TiN, and the individual thicknesses were varied, but the total thickness was fixed at 200 nm. All cell structures exhibited relatively stable multi-level states of high-middle-low resistance (HR-MR-LR), which guarantee the reliability of the multilevel phase-change random access memory (PRAM). The amorphousto-multilevel crystallization rate was evaluated from a graph of resistance (R) vs. pulse duration (T) obtained by the nanoscaled pulse sweeping at a fixed applied voltage (12 V). For all structures, the phase-change rates of HR→MR and MR→LR were estimated to be approximately t<20 ns and t<40 ns, respectively, and the states were relatively stable. We believe that the doublestack structure of an appropriate Ge-Sb-Te film separated by barrier metal (TiN) can be optimized for high-speed and stable multilevel PRAM.