• 대한환경공학회지
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• 제31권11호
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• pp.983-988
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• 2009

본 연구는 산업단지 폐수종말처리 시설내로 유입되는 니켈폐수의 독성평가 및 이의 효과적 처리방안을 도출하기 위하여 수행되었다. 처리장내로 유입되는 폐수를 24시간 동안 1시간 간격으로 시료를 채취하여 니켈 농도를 분석한 결과 0.33 mg/L~116.0 mg/L의 농도범위로 조사되었으며, 평균 24.0 mg/L로 조사되었다. 본 대상폐수의 농축질화균을 이용한 니켈의 독성도 조사 결과 Nitrosomonas와 Nitrobacter에 대한 $IC_{50}$값이 각각 5.5 및 4.9 mg/L인 것으로 나타났으며, 이는 본 유입폐수를 5배 희석하여 주입하여도 질산화 미생물의 50%를 사멸시킬 수 있는 농도인 것으로 나타났다. 또한 Nickel hydroxide형성에 의한 니켈 제거효율 실험결과 응집 pH에 따라 잔류 니켈 농도는 pH 11에서 1.7 mg/L, pH 12에서 0.6 mg/L로 나타났으며, 이는 상기 니켈 함유 폐수의 $NH_4$-N 및 $NO_3$-N에 대한 $IC_{50}$ 독성농도 조사 결과와 비교시 69.1~89.1% 및 65.3~87.8%의 독성도가 제거될 것으로 판단된다. 따라서 pH 10~11 이상으로 니켈 함유폐수를 응집처리 후 생물학적 처리를 수행한 결과 83.8%~99.4%의 범위로 평균 97.6%의 질산화 반응효율을 얻을 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제38권6호
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• pp.342-351
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• 2017

뉴럴 디코딩은 뉴론이 발화한 스파이크 트레인으로부터 뉴론에 인가된 원 자극을 추정하는 작업을 말한다. 디코딩은 뉴론들끼리 어떻게 신호를 주고 받는 지를 이해함으로써 궁극적으로 뇌가 어떻게 정보처리를 하는 지 이해하는 기초적인 작업이다. 이 논문에서 우리는 3가지 뉴럴 디코딩 방법, 즉 빈도 디코딩, 시간 디코딩, 군집 디코딩 방법에 대해 설명하겠다. 빈도 디코딩은 자극에 대한 스파이크의 발화빈도 정보를 이용하여 자극을 복원하는 방법을 말한다. 역사적으로 가장 먼저 시도되었고 가장 간단한 디코딩 방법이다. 그러나 정수 개인 스파이크 개수로부터 빈도를 계산하는 과정에서 빈도자체가 불연속이고 양자화될 가능성이 높기 때문에 간단하고 정적인 자극이 아닌 경우 빈도 디코딩으로는 자극을 복원하기 어렵다는 한계를 가지고 있다. 시간 디코딩은 스파이크 발생 빈도가 아닌 개별 스파이크들의 발생시각을 이용한 디코딩 방법을 말하며 실제 빠르게 변화하는 자극의 경우 신경세포는 빈도 디코딩이 아니라 시간 디코딩을 통해 자극을 추정하는 것으로 이해되고 있다. 군집 디코딩은 단일 신경세포가 아닌 군집 신경세포로부터 자극을 복원하는 방법이다. 군집 디코딩은 단일 신경 세포 디코딩에 비해 신경 세포의 가변성에 따른 불확실성을 감소시킬 수 있고 서로 다른 자극의 특성을 동시에 표현할 수 있다는 장점을 갖는다. 이 논문에서는 먼저 세 가지 뉴럴디코딩 방법에 대해 소개하고 정보이론이 뉴럴디코딩에 어떻게 적용되는 지를 다룬 후 마지막으로 최근에 각광받고 있는 기계학습 방법에 의한 뉴럴 디코딩에 대해 다루도록 하겠다.

• 대한의용생체공학회:의공학회지
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• 제39권3호
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• pp.124-133
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• 2018

We tried to investigate the changes in cortical activities according to emotional valence states during watching video clips. We examined the neural basis of two emotional states (positive and negative) using spectral power analysis and brain functional connectivity analysis of cortical current density time-series reconstructed from high-density electroencephalograms (EEGs). Fifteen healthy participants viewed a series of thirty-two 2 min emotional video clips. Sixty-four channel EEGs were recorded. Distributed cortical sources were reconstructed using weighted minimum norm estimation. The temporal and spatial characteristics of spectral source powers showing significant differences between positive and negative emotion were examined. Also, correlations between gamma-band activities and affective valence ratings were determined. We observed the changes of cortical current density time-series according to emotional states modulated by video clip. Gamma-band activities showed significant difference between emotional states for thirty seconds at the middle and the latter half of the video clip, mainly in prefrontal area. It was also significantly anti-correlated with the self-ratings of emotional valence. In addition, the gamma-band activities in frontal and temporal areas were strongly phase-synchronized, more strongly for negative emotional states. Cortical activities in frontal and temporal areas showed high spectral power and inter-regional phase synchronization in gamma-band during negative emotional states. It is inferred that the higher amygdala activation induced by negative stimuli resulted in strong emotional effects and caused strong local and global synchronization of neural activities in gamma-band in frontal and temporal areas.

• 대한의용생체공학회:의공학회지
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• 제38권2호
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• pp.62-73
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• 2017

To identify a solution for the restricted availability of healthy lungs and the high risk of immune rejections following organ transplantation, tissue engineering techniques for culturing lungs have been studied by many research groups. The most promising method for culturing lungs is the utilization of a bio-scaffold that was prepared using harvested organs from human donors or other animals by removing their original cells. In this study, a pulsatile perfusion pump was used to alleviate the cell removal effect with the high fluid-dynamic power of the perfusion stream during the decellularization process, while other conventional studies focused on chemical methods to identify efficient detergents. The purpose of this study was to analyze the developed device by using energy equivalent pressure (EEP), which is an indicator of pulsatility, to understand the characteristics of pulsatile energy transmitted according to the load size by using the artificial model and compare it with the measured EEP. The pulsatility of the device can be estimated with the concept of fluid-dynamic energy during a particular constant time period or fluid-dynamic power represented as EEP and EEP increment. Because the measured EEP of perfusion flow during decellularization can be changed by the amount of fluid leakage and the degree of clogging in the capillary vessels, EEP should be measured to determine whether the decellularization is progressing without problems. The decrement of EEP caused by the high perfusion resistance was observed from some experimental results that were obtained with artificial models. EEP can be used to monitor the decellularization process after analyzing the varying EEP according to the amount of load. It was confirmed that the EEP was maintained at a high level in the experiment using the harvested lungs from 12-13-week-old rats. In addition, it was confirmed that the cell removal time was faster than when continuous perfusion was performed. In this study, pulsatile power delivered to the lungs was measured to monitor the process of cell removal, and it serve as the evidence for efficient decellularization.

• 한국토양비료학회지
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• 제39권3호
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• pp.173-183
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• 2006

서낙동강 유역에서 USLE모형을 이용하여 농경지의 작물생산량 및 농업용수 수질과 관련 있는 농경지의 토양침식량을 평가하였다. 모형인자의 data set은 구축에 드는 노력과 시간의 소모를 최소화하고자 정밀토양도, 인공위성 영상 및 DEM자료로부터 RS와 GIS를 이용하여 구축하였는데, 토양상별 K 인자를 정밀토양도에 적용하여 주제도를 작성하고, 인공위성 영상(Landsat TM)으로부터 토지 피복도를 작성하여 C 및 P 인자의 주제도를 작성하였으며, DEM으로부터 LS 인자 주제도를 작성하였다. R인자는 서낙동강 유역 내에 위치하는 김해농업기술센터의 AWS 자료를 이용하여 계산하였다. 농경지발생 토양침식량은 유역전체 발생량의 31.5%였고, 농경지 토양유실량의 97.5%는 밭토양에서 일어나는 것으로 나타났다. 이는 서낙동강 유역이 삼각주평야지대로 경사가 거의 없으나 밭토양의 30.4%는 severe 및 very severe의 침식정도에 분포하였기 때문이다. 또한 식생의 토지 피복 상태 및 강우량의 정도에 따라 작물재배기(5월~9월)와 비재배기(10월~4월)로 나누어 토양침식량을 평가한 결과, 작물재배기는 연간 토양유실위험도와 유사한 경향이었고, 작물비재배포기는 R 값이 작물재포기의 약 1/5에 불과하였음에도 산과 인접한 경사지 밭토양의 일부는 severe 및 very severe의 토양침식 등급을 나타내어서 토양침식 관리에 주의가 필요하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8553-8557
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• 2016

Background: Accurate dose assessment and correct identification of irradiated from non-irradiated people are goals of biological dosimetry in radiation accidents. Objectives: Changes in the FDXR and the RAD51 gene expression (GE) levels were here analyzed in response to total body exposure (TBE) to a 6 MV x-ray beam in rats. We determined the accuracy for absolute quantification of GE to predict the dose at 24 hours. Materials and Methods: For this in vivo experimental study, using simple randomized sampling, peripheral blood samples were collected from a total of 20 Wistar rats at 24 hours following exposure of total body to 6 MV X-ray beam energy with doses (0.2, 0.5, 2 and 4 Gy) for TBE in Linac Varian 2100C/D (Varian, USA) in Golestan Hospital, in Ahvaz, Iran. Also, 9 rats was irradiated with a 6MV X-ray beam at doses of 1, 2, 3 Gy in 6MV energy as a validation group. A sham group was also included. After RNA extraction and DNA synthesis, GE changes were measured by the QRT-PCR technique and an absolute quantification strategy by taqman methodology in peripheral blood from rats. ROC analysis was used to distinguish irradiated from non-irradiated samples (qualitative dose assessment) at a dose of 2 Gy. Results: The best fits for mean of responses were polynomial equations with a R2 of 0.98 and 0.90 (for FDXR and RAD51 dose response curves, respectively). Dose response of the FDXR gene produced a better mean dose estimation of irradiated "validation" samples compared to the RAD51 gene at doses of 1, 2 and 3 Gy. FDXR gene expression separated the irradiated rats from controls with a sensitivity, specificity and accuracy of 87.5%, 83.5% and 81.3%, respectively, 24 hours after dose of 2 Gy. These values were significantly (p<0.05) higher than the 75%, 75% and 75%, respectively, obtained using gene expression of RAD51 analysis at a dose of 2 Gy. Conclusions: Collectively, these data suggest that absolute quantification by gel purified quantitative RT-PCR can be used to measure the mRNA copies for GE biodosimetry studies at comparable accuracy to similar methods. In the case of TBE with 6MV energy, FDXR gene expression analysis is more precise than that with RAD51 for quantitative and qualitative dose assessment.

• 대한간호학회지
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• 제22권4호
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• pp.526-551
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• 1992

The purpose of this study was to identify the commonalities of various nursing interventions and effective intervention methods in each intervention through analysis and synthesis of many accumulated research papers. The study analyzed the effects of various nursing interventions on anxiety and /or stress. For this purpose, 64 experimental studies with randomized or nonequivalent control group pre-test-posttest design were selected from journals of medical and nursing schools, the Korean Nurse, the Korean Nurses' Academic Society Journal, the Cetnral Journal of Medicine, the New Medical Journal, the Nurse Monthly, and from theses and dissertations conducted from 1970 to 1991. The selected studies nor classified according to three characteristics : 1) the research samuel, 2) types and methods of nursing interventions, and 3) statistical tests. The following analysis was done : 1) Confirmation of the accuracy of data drawn from each study by paired review, 2) Estimation of the homogenity of pre-test scores of the dependent variable between control and experimental groups warranted the effect size of post-scores, 3) If the homogenity of pre-test scores did not warrant, the change scores from pre-test to post-test were used to estimate the effect size, 4) Use of the effect size of each study among homogenious studies was tested for each intervention method, such as relaxation, information, and touch and /or support. Finally, for the studies not showing homogenity, an ANOVA test was used to identify patterns for each intervention. Some findings are summarized as follow : The effect sizes for relaxation and information were greater than those for touch and /or supportive technique. Studies using random assignment had greater effect sizes than nonrandomized sample studies using the same intervention. For healthy people, group education was more effective than individual teaching. However, for patients, relaxation and touch and /or supportive techniques given on individual basis were more effective than when given in a group situation. Measuring anxiety and stress by biological indicators was less effective than by self-report. Budzynski's relaxation method was the most effective. The more frequently the techniques applied, the larger the effect size. On the bases of these findings, the following recommendations were made : 1. A combination of information, relaxtion, and touch-supportive techniques should be used for greater effect in reducing the level of anxiety and /or stress. 2. Information is the first choice of intervention to reduce the level of anxiety and /or stress of healthy People : other interventions may be added depending on the conditions of the subjects.

• 한국환경과학회지
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• 제22권8호
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• pp.925-935
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• 2013

In this study, a comprehensive field monitoring was conducted to understand habitat conditions of fish species in up and downstream of Hoengseong Dam. Based on the monitoring data, riverine health conditions such as composition ratio of fish species, bio-diversity (dominance index, diversity, evenness and richness), index of biological integrity (IBI) and qualitative habitat evaluation index (QHEI) were assessed, and optimal ecological flowrates (OEF) were estimated using the habitat suitability indexes (HSI) established for three fish species Coreoleuciscus splendidus, Pungtungia herzi and Microphysogobio longidorsalis selected as icon species using the physical habitat simulation system (PHABSIM). The total number of species sampled was 20 species, and two species of Zacco platypus (30.4%) and C. splendidus (20.9%) dominated the fish community. As a result, it was revealed that IBI and QHEI values decreased from upstream to downstream along the river. The estimated IBI value ranged from 24 to 36 with average being 30.9 out of 50, rendering the site ecologically fair to good health conditions. HSI for C. splendidus were determined according to three different month in terms of season: Spring (April), Summer (August) and Autumn (October). HSI for flow velocity were estimated at 0.7 to 0.8 m/s for the Spring, 0.5 to 1.0 m/s for the Summer and 0.8 to 0.9 m/s for the Autumn. HSI for water depth were estimated at 0.3 to 0.5 m for the Spring; 0.3 to 0.5 m for the Summer; and 0.3 to 0.4 m for the Autumn. OEF was estimated at 4.2 and $6.5m^3/s$ for the Spring and Autumn, and $12.0m^3/s$ for the Summer. Overall, it was concluded that the Hoengseong Dam has been relatively well protected from the anthropogenic disturbance for the legally protected species including the endemic species studied in this study.

• Nutrition Research and Practice
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• 제6권5호
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• pp.436-443
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• 2012

Previous Korean total diet studies (KTDSs) have estimated dietary exposure to toxic chemicals based on 110-120 representative foods selected from over 500 foods appeared in the Korea National Health & Nutrition Examination Surveys (KNHANES), which would result in a possible underestimation. In order to find measures for a closer-to-real estimate of dietary exposure to heavy metals, this study examined the feasibility of mapping foods to the representative foods in the KTDS by comparing estimates. In mapping, those foods not analyzed in the 2009 KTDS (443 out of 559 foods appeared in the 2007 KNHANES) were mapped to the 114 representative foods used in the 2009 KTDS based on the closeness in regards to biological systematics and morphological similarity. Dietary exposures to total mercury and lead were re-estimated using the content of total mercury and lead in 114 foods analyzed in the 2009 KTDS, food intake, and individual's own body weight for respondents in the 2007 KNHANES instead of mean body weight of Koreans used in the 2009 KTDS. The re-estimates of exposure with mapping were approximately 50% higher than the original estimates reported in the 2009 KTDS. In addition, mapping enabled the comparison of percentile distribution of the exposure among populations of different age groups. In conclusion, estimates via mapping resulted in a more comprehensive estimation of dietary exposure to heavy metals present in foods that Koreans consume.

• 환경영향평가
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• 제29권3호
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• pp.230-238
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• 2020

본 연구는 비침습 샘플인 털을 이용하여 영월 한반도습지 내 서식하는 멧돼지(Sus scrofa)의 유전분석을 통하여 그들의 서식 생태를 유추하였다. 털 시료는 2018년 11월부터 2019년 5월까지 한반도습지(2.772㎢) 내에서 비빔목 및 헤어트랩을 이용하여 수집하였다. 털 시료로부터 DNA를 추출하여 개체의 종과 성을 PCR을 통해 파악하였으며 6개의 마이크로새틀라이트 마커를 이용하여 개체 구분과 개체 간 유전적 근연관계를 유추하였다. 수집된 털 시료 중 총 16개의 털이 멧돼지의 시료였으며, 이는 암컷 7마리, 수컷 3마리의 10개체로부터 수집된 것임이 판명되었다. 이 10개체의 유전적 관계를 추정해 본 결과, 이들이 만들어내는 45쌍 중에 9쌍의 개체가 친족관계일 가능성이 높게 나타났다. 개체 쌍의 친족관계와 털 시료가 채집된 위치를 함께 고려하여 본 결과, 한반도습지 일대에서 서식하는 멧돼지는 암컷과 그 자손으로써 모계 가족단위로 생활하는 것으로 추정되며, 이는 기존에 알려진 멧돼지의 습성과도 일치하는 결과이다. 그러나 본 연구에 사용된 샘플과 마이크로새틀라이트 마커의 수가 제한적이므로 향후 추가적인 분석이 필요하다.