• Ocean and Polar Research
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• 제36권4호
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• pp.383-394
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• 2014

The surface sediments from the manganese nodule exploration area of Korea in the Clarion-Clipperton fracture zone were investigated to understand the resource potential of and emplacement mechanism for rare earth elements (REEs). The sediments are categorized into three lithological units (Unit I, II and III from top to bottom), but into two groups (Unit I/II and Unit III) based on the distribution pattern of REEs. The distribution pattern of REEs in Unit I/II is similar to that of Post-Archean Australian Shale (PAAS), but shows a negative Ce anomaly and enrichment in heavy REEs (HREEs). In Unit III, the HREE enrichment and Ce anomaly is much more remarkable than Unit I/II when normalized to PAAS, which are interpreted as resulting from the absorption of REEs from seawater by Fe oxyhydroxides that were transported along the buoyant plume from remotely-located hydrothermal vents. It is supported by the PAAS-normalized REE pattern of Unit III which is similar to those of seawater and East Pacific Rise sediments. Meanwhile, the PAAS-normalized REE pattern of Unit I/II is explained by the 4:1 mixing of terrestrial eolian sediment and Unit III from each, indicating the much smaller contribution of hydrothermal origin material to Unit I/II. The studied sediments have the potentiality of a low-grade and large tonnage REE resource. However, the mining of REE-bearing sediment needs a large size extra collecting, lifting and treatment system to dress and refine low-grade sediments if the sediment is exploited with manganese nodules. It is economically infeasible to develop low-grade REE sediments at this moment in time because the exploitation of REE-bearing sediments with manganese nodules increase the mining cost.

• Clinical Endoscopy
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• 제57권2호
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• pp.181-190
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• 2024

Background/Aims: Radiofrequency ablation (RFA) is the first-line therapy for dysplastic Barrett's esophagus (BE). Therefore, cryotherapy has emerged as an alternative treatment option. This study aimed to compare the efficacies of these two techniques based on the rates of complete eradication of intestinal metaplasia (CE-IM) and dysplasia (CE-D). Adverse events and recurrence have also been reported. Methods: An electronic search was conducted using the Medline (PubMed), Embase, LILACS, and Google Scholar databases until December 2022. Studies were included comparing cryotherapy and RFA for treating dysplastic BE with or without early esophageal neoplasia. This study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results: Three retrospective cohort studies involving 627 patients were included. Of these, 399 patients underwent RFA, and 228 were treated with cryotherapy. There was no difference in CE-IM (risk difference [RD], -0.03; 95% confidence interval [CI], -0.25 to 0.19; p=0.78; I²=86%) as well as in CE-D (RD, -0.03; 95% CI, -0.15 to 0.09; p=0.64; I²=70%) between the groups. The absolute number of adverse events was low, and there was no difference in the recurrence rate. Conclusions: Cryotherapy and RFA were equally effective in treating dysplastic BE, with or without early esophageal neoplasia.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8127-8134
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• 2014

Background: Qigong is highly favoured among Asian breast cancer survivors for enhancing health. This study examined the hypothesis that quality of life (QoL) in the Qigong group is better than the placebo (aerobic) or usual care group. Materials and Methods: A total of 197 participants were randomly assigned to either the 8-week Kuala Lumpur Qigong Trial or control groups in 2010-2011. Measurement taken at baseline and post-intervention included QoL, distress and fatigue. Analysis of covariance (ANCOVA) and Kruskal Wallis were used to examine for differences between groups in the measurements. Results: There were 95 consenting participants in this 8week trial. The adherence rates were 63% for Qigong and 65% for the placebo group. The Qigong group showed significant marginal improvement in Quality of life scores compared to placebo (mean difference=7.3 unit; p=0.036), compared to usual care (mean difference=6.7 unit; p=0.048) on Functional Assessment Cancer Therapy-Breast measure. There were no significant changes between the placebo and usual care groups in fatigue or distress at post intervention (8-week). Conclusions: Cancer survivors who participated in the Qigong intervention showed slightly better QOL. Follow up studies are greatly needed to evaluate which subgroups may best benefit from Qigong. With a steep rise of cancer survivors, there is an urgent need to explore and engage more cultural means of physical activity to fight side effects of treatment and for cancer control in developing countries.

• 대한화학회지
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• 제50권5호
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• pp.385-393
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• 2006

연구에서는 고등학교 화학 수업에서 개방적 가설검증 학습모형을 적용한 과학 탐구학습을 실시하고, 학생들의 인지 수준에 따른 과학 탐구능력, 과학 수업에 대한 태도에 미치는 효과와 수업에 대한 인식을 알아보았다. 서울에 소재한 남자 고등학교 2학년 4개 학급의 학생들(92명)을 대상으로 개방적 가설검증 학습모형을 적용한 과학 탐구학습을 실시한 처치집단과 실험과정이 모두 제시된 실험 수업을 실시한 통제집단으로 배치한 후, 화학의 ‘금속과 그 이용' 단원에 대해서 수업을 실시하였다. 연구 결과에 의하면, 개방적 가설검증 학습모형을 적용한 과학 탐구학습은 과학 탐구능력 향상에 관해서 실험설계, 자료 변환 및 해석, 가설검증의 영역에서 유의미한 효과가 있었으며 문제 파악 및 정의, 가설설정의 영역에서는 효과가 없었다. 한편, 개방적 과학 탐구학습에서 학생들의 역할 및 수행할 과제의 증가로 인해 과학 수업에 대한 태도는 처치집단에 부정적인 효과가 나타났다.

• Journal of Korean Neurosurgical Society
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• 제54권5호
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• pp.384-389
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• 2013

Objective : Use of quantitative computed tomography (CT) to evaluate bone mineral density was suggested in the 1970s. Despite its reliability and accuracy, technical shortcomings restricted its usage, and dual-energy X-ray absorptiometry (DXA) became the gold standard evaluation method. Advances in CT technology have reduced its previous limitations, and CT evaluation of bone quality may now be applicable in clinical practice. The aim of this study was to determine if the Hounsfield unit (HU) values obtained from CT correlate with patient age and bone mineral density. Methods : A total of 128 female patients who underwent lumbar CT for back pain were enrolled in the study. Their mean age was 66.4 years. Among them, 70 patients also underwent DXA. The patients were stratified by decade of life, forming five age groups. Lumbar vertebrae L1-4 were analyzed. The HU value of each vertebra was determined by averaging three measurements of the vertebra's trabecular portion, as shown in consecutive axial CT images. The HU values were compared between age groups, and correlations of HU value with bone mineral density and T-scores were determined. Results : The HU values consistently decreased with increasing age with significant differences between age groups (p<0.001). There were significant positive correlations (p<0.001) of HU value with bone mineral density and T-score. Conclusion : The trabecular area HU value consistently decreases with age. Based on the strong positive correlation between HU value and bone mineral density, CT-based HU values might be useful in detecting bone mineral diseases, such as osteoporosis.

• 한국작물학회지
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• 제37권6호
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• pp.541-549
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• 1992

벼 담수표면직파재배시 파종기 및 품종을 기상 및 재배 환경과의 관계를 구조적으로 분석하여 담수직파에서 흔히 발생하는 도복의 방상대책과 후기등숙생리를 검토한 결과는 아래와 같다. 1. 초기생육형수질중에서 출아일수는 조기파종일수록 길었으며 단립면적당 입묘수 및 입묘율은 파종이 늦을수록 그리고 만생종일수록 많고 양호하였다. 2. 단립면적당 수수는 파종이 늦을수록 감소하였으며 유효경비율은 만파인 5월 21일 파종구에서 가장 낮았다. 출수개화일수는 파종기가 늦을수록 단축되었으며 등숙기간중 강우분포는 조생종의 등숙기에 많았고 중ㆍ만생종의 등숙기에는 비교적 적었다. 파종기별 및 품종의 숙기별 포장도복정도는 파종이 빠를수록, 그리고 숙기가 빠를수록 컸다. 5. 수량 및 수량구성형질은 파종이 빠를수록 많고 양호했으며 특히 등숙비율은 그차이가 뚜렸하였다.

• Safety and Health at Work
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• 제5권2호
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• pp.86-90
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• 2014

Background: Urinary 1-hydroxypyrene (1-OHP) was selected as a biomarker of polycyclic aromatic hydrocarbons (PAHs) to explore the accumulation level in the bodies of workers at rubber smoke sheet factories in southern Thailand. Methods: Spot urine samples were taken from four groups of workers from June 2006 to November 2007. The nonexposure or control groups included habitual cigarette smokers and nonsmokers. The other two groups were workers exposed to particle-bound PAHs from rubber wood smoke and they were nonsmokers. All spot urine samples were analyzed for 1-OHP and creatinine levels. Results: The mean${\pm}$standard deviation urinary 1-OHP in the control group of habitual smokers and the nonsmokers was $0.24{\pm}0.16{\mu}mol/mol$ creatinine and not-detected to $0.14{\mu}mol/mol$ creatinine, respectively. In the workers, the 1-OHP levels on workdays had no significant difference from the 1-OHP levels on the days off. The yearly average 1-OHP level was $0.76{\pm}0.41{\mu}mol/mol$ creatinine whereas the average 1-OHP level during 10 consecutive workdays was $1.06{\pm}0.29{\mu}mol/mol$ creatinine (p > 0.05). Conclusion: The urinary 1-OHP levels of workers exposed to PAHs were high. The accumulation of 1-OHP in the body was not clear although the workers had long working hours with few days off during their working experience. Therefore, a regular day off schedule and rotation shift work during high productive RSS should be set for RSS workers.

• 한국콘텐츠학회논문지
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• 제16권12호
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• pp.468-479
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• 2016

본 연구는 중환자 첫 발열 평가 가이드라인에 대한 간호사의 지식과 수행 정도를 확인하고자 수행된 연구이다. 대상자는 2개 병원 내 외과병동 및 중환자실에서 근무하는 총 145명의 간호사를 대상으로 하였다. 자료 분석은 SPSS 19.0 프로그램을 활용하여 분석하였고, 중환자 첫 발열 평가 가이드라인의 지식과 수행의 평균 평점은 각각 0.70점과 3.08점이다. 가이드라인의 근거수준 1영역은 지식과 수행 상위군에서 하위군보다 유의하게 높은 수행 점수를 나타냈고, 근거수준 3영역은 지식 상위군보다 지식 하위군이 더 높은 수행 점수를 나타냈다. 대상자의 가이드라인에 대한 지식과 수행은 유의한 상관관계를 나타냈다. 결론적으로 본 연구는 중환자 첫 발열 평가 가이드라인에 대한 간호사의 지식과 수행력을 향상시키고 근거기반실무를 개선시킬 필요가 있음을 제시하였다.

• Journal of Periodontal and Implant Science
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• 제23권3호
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• pp.564-576
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• 1993

The purpose of this study was to evaluate the effects of Nd:YAG laser treatment on removal of smear layer and exposure of dentinal tubules. The experimental specimens were obtained from root planed surface of 30 human teeth which were extracted due to severe periodontal disease. The specimens were assigned randomly of three groups: root planed group, Tetracycline HCl(100mg/ml, 5min) group, and Nd:YAG laser ($Laser-35^{TM}$, U.S.A. 5 seconds )group. Nd:YAG laser group was divided into 4 subgroups according to 3.0W, 3.5W, 4.0W, 4.5W of power. The surface change of specimens were evaluated by scanning electron microscopy. The number of exposed dentinal tubules and percentage of area occupied by dentinal tubule orifices per unit area between each group was statistically analyzed by paired Student t-test. The results were as follows: 1. By root planing only, dentinal tubule was not exposed, but scale-like smear layer and parallel instrument tracks were resulted. 2. Tetracycline HCl treated surfaces exhibited the small number of partially exposed dentinal tubules with long orifices. The number($3.80{\pm}0.79$) of exposed dentinal tubules on Tetracycline HCl group was significantly less than that in laser groups above 3.5W of power(P<0.001), and the percentage ($0.68{\pm}0.19$) of area occufied by dentinal tubule orifices per unit area($192\;{\mu}m^2$) was significantly lower than that of any laser group(P<0.001). 3. The laser group irradiated with 4.5W of power showed both the most number($10.60{\pm}0.97$) of exposed dentinal tubules among the experimental groups, and the highest percentage($3.75{\pm}0.55\;%$) of area occupied by dentinal tubule orifices. 4. Energy Surge during laser pulsing and overlapping passes of the fiber resulted in melted and resolidified surface textures with lava-like appearance.

• 치과방사선
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• 제20권1호
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• pp.53-62
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• 1990

This experiment was performed to clarify the effects of /sup 60/Co gamma irradiation on secretory function, amylase activity and contents of nucleic acids of parotid gland in rat. Experimental animals were divided into 6th hours, 3rd, 7th, 14th and 28th days after irradiation and control. The experimental animals are singly irradiated with 20Gy (2,000rad) through protective lead block. Secretory function of parotid gland was evaluted by uptake and clearance of /sup 99m/TcO₄. /sup 99m/TcO₄. 0.2μ ci/gm, was injected into peritonium in uptake groups. Rats were sacrified with cervical dislocation after 30 minutes and gland was excised. In the clearance group. pilocarpine nitrate (8㎎/㎏) was intraperitoneally injected at 30 minutes after /sup 99m/TcO₄ injection and rats were sacrified 30 minutes after pilocarpine injection. Radioactivity of excised parotid gland was measured by using of gamma counter and stimulation-secretion coefficients, uptake radioactivity divided by clearance radioactivity, was calculated. Amylase activity and contents of DNA and RNA were determined by spectrophotometry. The results obtained were as follows: 1. In the uptake test, the radioactivity of /sup 99m/TcO₄ per unit weight increase in experimental group except 6th hours group, compared with control groups and showed a peak at 3rd days after irradiation. 2. In the clearance test, the radioactivity of /sup 99m/cO₄per unit weight rose to a peak at 3rd days after irradiation and gradually recovered thereafter. 3. Stimulation-secretion coefficient of parotid gland decreased at 6th hours, 3rd and 7th days after irradiation, and gradually increased. 4. Amylase activity of parotid gland decreased in 3rd and 7th days group, and especially lowest in 3rd days after irradiation. 5. The contents of DNA showed no definite difference in all the experimental groups, but RNA was seemed to decrease with time after irradiation.