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Gamma-ray Full Spectrum Analysis for Environmental Radioactivity by HPGe Detector
Meeyoung Jeong,Kyeong Beom Lee,Kyeong Ja Kim,Min-Kie LEE,Ju-Bong HAN 한국우주과학회 2014 Journal of Astronomy and Space Sciences Vol.31 No.4
Odyssey, one of the NASA’s Mars exploration program and SELENE (Kaguya), a Japanese lunar orbiting spacecraft have a payload of Gamma-Ray Spectrometer (GRS) for analyzing radioactive chemical elements of the atmosphere and the surface. In these days, gamma-ray spectroscopy with a High-Purity Germanium (HPGe) detector has been widely used for the activity measurements of natural radionuclides contained in the soil of the Earth. The energy spectra obtained by the HPGe detectors have been generally analyzed by means of the Window Analysis (WA) method. In this method, activity concentrations are determined by using the net counts of energy window around individual peaks. Meanwhile, an alternative method, the so-called Full Spectrum Analysis (FSA) method uses count numbers not only from full-absorption peaks but from the contributions of Compton scattering due to gamma-rays. Consequently, while it takes a substantial time to obtain a statistically significant result in the WA method, the FSA method requires a much shorter time to reach the same level of the statistical significance. This study shows the validation results of FSA method. We have compared the concentration of radioactivity of 40K, 232Th and 238U in the soil measured by the WA method and the FSA method, respectively. The gamma-ray spectrum of reference materials (RGU and RGTh, KCl) and soil samples were measured by the 120% HPGe detector with cosmic muon veto detector. According to the comparison result of activity concentrations between the FSA and the WA, we could conclude that FSA method is validated against the WA method. This study implies that the FSA method can be used in a harsh measurement environment, such as the gamma-ray measurement in the Moon, in which the level of statistical significance is usually required in a much shorter data acquisition time than the WA method.
Gamma-ray Full Spectrum Analysis for Environmental Radioactivity by HPGe Detector
Jeong, Meeyoung,Lee, Kyeong Beom,Kim, Kyeong Ja,Lee, Min-Kie,Han, Ju-Bong The Korean Space Science Society 2014 Journal of Astronomy and Space Sciences Vol.31 No.4
Odyssey, one of the NASA's Mars exploration program and SELENE (Kaguya), a Japanese lunar orbiting spacecraft have a payload of Gamma-Ray Spectrometer (GRS) for analyzing radioactive chemical elements of the atmosphere and the surface. In these days, gamma-ray spectroscopy with a High-Purity Germanium (HPGe) detector has been widely used for the activity measurements of natural radionuclides contained in the soil of the Earth. The energy spectra obtained by the HPGe detectors have been generally analyzed by means of the Window Analysis (WA) method. In this method, activity concentrations are determined by using the net counts of energy window around individual peaks. Meanwhile, an alternative method, the so-called Full Spectrum Analysis (FSA) method uses count numbers not only from full-absorption peaks but from the contributions of Compton scattering due to gamma-rays. Consequently, while it takes a substantial time to obtain a statistically significant result in the WA method, the FSA method requires a much shorter time to reach the same level of the statistical significance. This study shows the validation results of FSA method. We have compared the concentration of radioactivity of $^{40}K$, $^{232}Th$ and $^{238}U$ in the soil measured by the WA method and the FSA method, respectively. The gamma-ray spectrum of reference materials (RGU and RGTh, KCl) and soil samples were measured by the 120% HPGe detector with cosmic muon veto detector. According to the comparison result of activity concentrations between the FSA and the WA, we could conclude that FSA method is validated against the WA method. This study implies that the FSA method can be used in a harsh measurement environment, such as the gamma-ray measurement in the Moon, in which the level of statistical significance is usually required in a much shorter data acquisition time than the WA method.
Jeong, Hoon Jae,Kim, Dae Won,Woo, Su Jung,Kim, Hye Ri,Kim, So Mi,Jo, Hyo Sang,Park, Meeyoung,Kim, Duk-Soo,Kwon, Oh-Shin,Hwang, In Koo,Han, Kyu Hyung,Park, Jinseu,Eum, Won Sik,Choi, Soo Young Springer-Verlag 2012 Molecules and cells Vol.33 No.5
<P>Parkinson's disease (PD) is a well known neurodegenerative disorder characterized by selective loss of dopaminergic neurons in the substantia nigra pars compact (SN). Although the exact mechanism remains unclear, oxidative stress plays a critical role in the pathogenesis of PD. DJ-1 is a multifunctional protein, a potent antioxidant and chaperone, the loss of function of which is linked to the autosomal recessive early onset of PD. Therefore, we investigated the protective effects of DJ-1 protein against SH-SY5Y cells and in a PD mouse model using a cell permeable Tat-DJ-1 protein. Tat-DJ-1 protein rapidly transduced into the cells and showed a protective effect on 6-hydroxydopamine (6-OHDA)-induced neuronal cell death by reducing the reactive oxygen species (ROS). In addition, we found that Tat-DJ-1 protein protects against dopaminergic neuronal cell death in 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine (MPTP)-induced PD mouse models. These results suggest that Tat-DJ-1 protein provides a potential therapeutic strategy for against ROS related human diseases including PD.</P>
Adjuvant role of macrophages in stem cell-induced cardiac repair in rats
Lim, Soo yeon,Cho, Dong Im,Jeong, Hye-yun,Kang, Hye-jin,Kim, Mi Ra,Cho, Meeyoung,Kim, Yong Sook,Ahn, Youngkeun Nature Publishing Group UK 2018 Experimental and molecular medicine Vol.50 No.11
<▼1><P>Bone marrow-derived mesenchymal stem cells (BMMSCs) are used extensively for cardiac repair and interact with immune cells in the damaged heart. Macrophages are known to be modulated by stem cells, and we hypothesized that priming macrophages with BMMSCs would enhance their therapeutic efficacy. Rat bone marrow-derived macrophages (BMDMs) were stimulated by lipopolysaccharide (LPS) with or without coculture with rat BMCs. In the LPS-stimulated BMDMs, induction of the inflammatory marker iNOS was attenuated, and the anti-inflammatory marker Arg1 was markedly upregulated by coculture with BMMSCs. Myocardial infarction (MI) was induced in rats. One group was injected with BMMSCs, and a second group was injected with MIX (a mixture of BMMSCs and BMDMs after coculture). The reduction in cardiac fibrosis was greater in the MIX group than in the BMC group. Cardiac function was improved in the BMMSC group and was substantially improved in the MIX group. Angiogenesis was better in the MIX group, and anti-inflammatory macrophages were more abundant in the MIX group than in the BMMSC group. In the BMMSCs, interferon regulatory factor 5 (IRF5) was exclusively induced by coculture with macrophages. IRF5 knockdown in BMMSCs failed to suppress inflammatory marker induction in the macrophages. In this study, we demonstrated the successful application of BMDMs primed with BMMSCs as an adjuvant to cell therapy for cardiac repair.</P></▼1><▼2><P><B>Heart attacks: mixed cell therapy for heart regeneration</B></P><P>A tailored technique involving stem cells and anti-inflammatory immune cells shows promise for repairing heart tissue damage. Immune cells called anti-inflammatory macrophages are vital for healing of the heart following a heart attack. Youngkeun Ahn, Yong Sook Kim and co-workers at Chonnam National University Hospital in Gwangju, South Korea trialed a novel stem cell therapy on rats to improve cardiac repair. They took bone marrow-derived macrophages and stem cells from each rat and incubated the two cell types together to create individualized treatments. Following induced heart attacks, they injected one group of rats with both cell types, and another group with stem cells only. While heart function improved in both groups, the group treated with both cell types showed significant improvements with a greater reduction in cardiac fibrosis and increased the reparative activity of macrophages.</P></▼2>
김정욱(Jeongwook Kim),정지완(Jiwan Jeong),차미영(Meeyoung Cha) 한국HCI학회 2020 한국HCI학회 학술대회 Vol.2020 No.2
자연어처리(NLP)는 우리가 일상 생활에서 사용하는 언어인 자연어의 의미를 분석하고 추출하는 일련의 작업을 의미한다. 이를 위해서는 의미 단위로 문장을 분해하는 토크나이징(Tokenizing)이 필수적이며, 이를 위해 다양한 한국어 토크나이저가 개발되었다. 하지만 대다수의 토크나이저들은 급격히 증가하는 신조어에 적절히 대응하지 못해 잘못된 결과를 도출하고, 따라서 사용자들은 사용자 사전 추가 기능을 이용해 이를 수동으로 보정해야 한다. 포털 뉴스는 당시 발생한 주요 사건들에 대한 기사를 일 3 만여 건 제공하고 있으며, 이들의 제목은 조사가 생략된 경우가 많아 비지도학습으로 단어를 추출하기 적절하다. 따라서 본 눈문에서는 오픈소스로 공개된 한국어 NLP 도구인 soynlp 를 네이버 뉴스 기사 전체에 적용하여 매주 신조어를 추출하였고, 이를 기존의 한국어 토크나이저에 추가하여 신조어에 원활히 대응함을 확인하였다.