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      • KCI등재

        청소년 인터넷 중독 검사 방법의 통계적 고찰 및 개선 -Young의 척도를 중심으로

        박찬정 ( Chan Jung Park ),김형철 ( Hyung Chul Kim ),고영민 ( Young Min Ko ),현정석 ( Jung Suk Hyun ),김철민 ( Cheol Min Kim ) 한국컴퓨터교육학회 2010 컴퓨터교육학회 논문지 Vol.13 No.4

        국내외에서 이루어진 기존의 인터넷 중독 검사에 대한 연구는 다양하며 방대하지만, 대부분의 연구가 중독도 검사를 위한 항목추출이거나 항목들을 이용한 중독도 분석이었지 항목간의 분석을 통한 차별화는 이루어지지 않았다. 본 논문에서는 리즈렐과 데이터마이닝 기법을 이용하여 Young의 인터넷 중독 검사방법을 고찰하고 문제점을 지적한 후, 검사 방법에 대한 대안을 제안한다. 이를 위해 Young의 척도를 이용하여 청소년 440명을 대상으로 설문을 실시하고, 요인분석을 통해 Young 척도의 문제점을 분석한다. 또한, 데이터 마이닝 알고리즘인 J48 및 PART를 이용하여 설문문항들 중에서 인터넷 중독도를 구분 지을 수 있는 항목들을 선별하고 이를 기반으로 인터넷 중독 학생들을 진단하고 처방하는데 활용하는 방법을 제안한다. So far, the researches about the Internet addiction testing are diverse and enormous. However, since the testing factors have the same importance, there is no discrimination among the factors. In our paper, we analyze the problems of the existing researches by using Lisrel and data mining algorithms. Next, we propose an alternative for the Internet addiction testing. In order to accomplish these, we make an questionnaire consisted of Young`s test and then, we asked to 440 primary and secondary school students. In addition, we analyzed the problems of Young`s test with factor analysis and then, we distinguish more important items from others with J48 and PART. Finally, based on this analysis, we propose a method to diagnose addicted students and prescribe them.

      • KCI등재

        일 대학병원에 입원한 노년기 양극성 장애 환자의 인구학적 및 임상적 특징

        조숙현(Sook Hyun Cho),정한용(Han Yong Jung),권영준(Young Jun Kwon),이소영(So Young Lee),김양래(Yang Rae Kim),김윤정(Yun Jung Kim) 대한노인정신의학회 2006 노인정신의학 Vol.10 No.2

        Objectives : As the elderly population is continuing to increase, psychiatric diseases of the elderly are becoming an important social issue. This study looks into the demographical and clinical features of the elderly patients diagnosed with bipolar disorder in a University hospital. Methods : The study subjects include patients admissioned in the closed wards of Soonchunhyang Seoul hospital and Cheonan hospital from March, 2000 to February, 2005 who met the DSM-IV-TR criteria for bipolar disorder at the time of discharge. A total of 146 patients (76 men, 70 women) medical records were studied retrospectively. Subjects older than the age of 50 at time of admission were grouped as the old age group, whereas those who were younger than 50 as the young age group. Also among the old age group, those who had the first onset of episode under the age of 50 were grouped as the early onset group, whereas those who had the first onset after the age 50 were grouped as the late onset group. Results : The number of bipolar disorder patients in the young age group and old age group were 73 and 73 respectively. The number of early onset group and late onset group were 46 and 23 respectively. The old age group had a relatively higher incidence of bipolar II disorder than the young age group. Also in the old age group there was a higher incidence of hypomanic or depressive episode rather than manic episode compared to the young age group. And in the old age group psychotic symptoms were less common and the mean admission length shorter than the young age group. Additionally in the old age group treatment with Lithium monotherapy or with no mood stabilizers at all were relatively common. Among the old age group, late onset group had a higher rate of bipolar II disorder than the early onset group. Conclusion : This study shows differences in the demographical and clinical features among different age groups. But additional research would be required to determine whether the bipolar disorders in the elderly or late onset group are actually a different type of disorder from those of the young.

      • Comparison of trophic factors changes in the hippocampal CA1 region between the young and adult gerbil induced by transient cerebral ischemia.

        Yan, Bing Chun,Park, Joon Ha,Kim, Sung Koo,Choi, Jung Hoon,Lee, Choong Hyun,Yoo, Ki-Yeon,Kwon, Young-Geun,Kim, Young-Myeong,Kim, Jong-Dai,Won, Moo-Ho Kluwer Academic/Plenum Publishers 2012 Cellular and molecular neurobiology Vol.32 No.8

        <P>In the present study, we investigated neuronal death/damage in the gerbil hippocampal CA1 region (CA1) and compared changes in some trophic factors, such as brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) and vascular endothelial growth factor (VEGF), in the CA1 between the adult and young gerbils after 5 min of transient cerebral ischemia. Most of pyramidal neurons (89%) were damaged 4 days after ischemia-reperfusion (I-R) in the adult; however, in the young, about 59% of pyramidal neurons were damaged 7 days after I-R. The immunoreactivity and levels of BDNF and VEGF, not GDNF, in the CA1 of the normal young were lower than those in the normal adult. Four days after I-R in the adult group, the immunoreactivity and levels of BDNF and VEGF were distinctively decreased, and the immunoreactivity and level of GDNF were increased. However, in the young group, all of their immunoreactivities and levels were much higher than those in the normal young group. From 7 days after I-R, all the immunoreactivities and levels were apparently decreased compared to those of the normal adult and young. In brief, we confirmed our recent finding: more delayed and less neuronal death occurred in the young following I-R, and we newly found that the immunoreactivities of trophic factors, such as BDNF, GDNF, and VEGF, in the stratum pyramidale of the CA1 in the young gerbil were much higher than those in the adult gerbil 4 days after transient cerebral ischemia.</P>

      • 노화가 인체 중간엽 줄기세포로부터 조골세포로의 증식 및 분화에 미치는 영향

        백기현,태현정,오기원,이원영,조정기,권순용,강무일,차봉연,이광우,손호영,강성구,김춘추 대한내분비학회 2003 Endocrinology and metabolism Vol.18 No.3

        연구배경: 일반적으로 골다공증과 연관된 위험인자로는 연령, 폐경, 약물, 불충분한 칼슘섭취, 만성질환 및 운동부족 등이 있는데, 특히 노화가 진행할수록 골밀도가 감소하는 것은 잘 알려져 있다. 노화와 관련하여 진행되는 골소실은 조골세포 및 전구조골세포의 기능적 결핍에 의한 골형성의 감소가 주요한 요인으로 여겨지고 있다. 그 동안 연령이 조골모 세포의 양과 조골모 세포로부터 성숙조골세포로의 분화 및 증식에 미치는 영향에 대한 일부 보고들이 있었으나 아직 일치된 견해는 없는 형편이다. 방법: 다양한 연령의 사람으로부터 골수를 채취, 중간엽 줄기세포가 포함된 단핵세포를 분리한 후 조골세포로 분화하기 좋은 조건하에서 배양하였다. 대상군은다시 젊은군과 노령군으로 구분하여 다양한 변수를 비교 분석하였다. 일차배양에서는 CFU-F를 계수하여 골수내 중간엽 줄기세포의 수를 추산하였고, 칼슘측정을 통하여 기질의 무기화 정도를 비교하였다. 계대배양후 이차배양에서는 시기별로 알카리성 포스파타제 활성도를 측정하고 오스테오칼신 mRNA의 발현을 관찰하여 젊은군과 노령군 사이의 증식능 차이를 비교하였다. 또한 이차배양 시기별로 MTT 측정을 하여 양군간에 증식능 차이가 있는지 알아보았다. 결과: 1. 일차배양 15일째에 평균 CFU-F의 수는 젊은군에서 유의하게 많았다(젊은군 148.3±28.9, 노령군 54.3±9.1, p=0.02). CFU-F의 평균면적은 젊은군에서 넓은 경향을 보였으나 통계적으로 유의하지는 않았다. 2. 일차배양 17일 경과 후 양군간에 기질 칼슘 침착정도는 유의한 차이를 보이지 않았다(젊은군 103.6±50.6, 노령군: 114.0±56.5, p=NS). 3. 이차배양 10일째에 젊은군에서 알카리성 포스파타제 활성도가 고령군에 비해 유의하게 높았다(젊은군: 935.5±115.0 U/mg, 노령군: 578.4±115.7U/mg,p.0.05). 고령군에서는 시간 경과에 따른 변화가 미약했으며 전반적으로 알카리성 포스파타제의 활성도가 젊은군에 비해 낮았다. 4. 이차배양도중 오스테오칼신 mRNA의 발현은 배양시기별로 젊은군에 비해 고령군에서 더 낮은 경향을 관찰할 수 있었다. 5. 이차배양 10일과 15일에 젊은군에서 노령군보다세포증식이 유의하게 증가된 양상을 보였다(10앓 젊은군 0.73±0.05, 노령군 0.58±0.04, p=0.05, 15일; 젊은군 0.80±0.05, 노령군 0.70±0.03, p=0.05).결론: 이상의 연구에서 저자들은 노령군에서 젊은군보다 골수 내 중간엽줄기세포의 수가 적고, 노령군에서 유래한 전구조골세포의 성숙조골세포로의 증식 및 분화가 젊은군 보다 감소해 있는 것을 관찰할 수 있었다. Background: Osteoblasts originate from osteoprogenitor cells in bone marrow stroma, termed mesenchymal stem cells (MSCs) or bone marrow stromal cells. Each MSC forms colonies (colony forming units-fibroblasts [CFL-Fs]) when cultured ex vivo. There are some reports about the age-related changes of the number and osteogenic potential of osteoprogenitor cells, but any relationship has not been clearly established in humans. In this study, we counted MSCs using CFU-Fs count and examined the proliferative capacity and differentiation potential of osteoprogenitor cells. Finally, we analyzed how these parameters varied with donor age. Methods: Bone marrow was obtained from the iliac crest of young (n=6, 27.2±8.6 years old) and old (n= 10, 57.4k6.7 years old) healthy donors. Mononuclear cells, including MSCs, were isolated and cultured in osteogenic medium. In primary culture, we compared the colony-forming efficiency of MSCs between the two groups and determined the matrix calcification. When primary culture showed near confluence, the cells were subcultured. Alkaline phosphatase activity, osteocalcin expression by RT-PCR and proliferative potential by MTT assay were examined by the time course of secondary culture. Results: At the 15th day of primary culture, the mean number of CFU-Fs was significantly higher in the younger donors (young: 148.3±28.9, old: 54.3±9.1, p=0.02) and the mean size of CFL-Fs was also larger in the younger donors than the older donors. However, matrix calcification was not different between the two groups (young: 103.6±50.6, old: 114.0±56.5, p=NS). In secondary culture, alkaline phosphatase activities were significantly lower in the older donors. The younger donors showed peak alkaline phosphatase activity at day 10, while the older donors didn't showed a remarkable peak (young: 935.5±115.OU/mg, old: 578.4±115.7U/mg, p<0.05). Total cell number as a proliferative index increased progressively during the secondary culture and a significantly greater cell number was noted in the younger donors. Osteocalcin expression was generally upregulated in the younger donors, but this was not statistically significant. Conclusion: Our study shows that the number of osteoprogenitor cells is decreased during aging and that the proliferative capacity and differentiation potential of osteoprogenitor cells seem to be reduced during aging (J Kor SOC Endocrinol 18:296-305, 2003).

      • KCI등재

        물의 종류를 달리한 동치미의 경도 변화 및 세포벽 관찰

        심영현,안기정,김지은 한국조리과학회 2004 한국식품조리과학회지 Vol.20 No.1

        The purpose of this study was to investigate the changes of hardness and microstructure of Dongchimi cooked with various source of water(distilled water, purified water, Cho Jung Carbonated Natureal water). This study was conducted to observe the change of pH, total acidity, salt content, turbidity, texture and microstructure. Dongchimi cooked with source of water of water was fermented at 10℃ for 46 days. The changes of pH on Dongchimi cooked with various source of water decreased in all samples during fermentation period, and then showed a slowly decrease after 12 days of fermentation. The total acidity of Dongchimi cooked with Cho Jung Carbonated Natural water was arrived slowly at best tasting condition 0.3~0.4 point compared with other conditions. So Dongchimi cooked with Cho Jung Carbonated Natural water was continued to the best tasting condition for end of fermentation. At early stage of fermentation, the changes of turbidity of Dongchimi used Cho Jung Carbonated Natural water showed highly as compared with other test condition for 12th days of fermentation. The maximum cutting force of chinese radish of Dongchimi showed the highest value among all at the 25th day of ripening and then decreased gradually. The maximum cutting force of chinese radish of Dongchimi used Cho Jung Carbonated Natural water was the highest compared with other conditions at 25th day of fermentation. The calcium content of Dongchimi juice used Cho Jung Carbonated Natural water was observed high at the early stage of fermentation and showed the highest value at 25th day of ripening. The calcium content of chinese radish and Dongchimi juice of Dongchimi cooked with water purifier was lower than that of Dongchimi cooked with Cho Jung Carbonated Natural water, and was higher than that of Dongchimi cooked with Distilled water at the early stage of fermentation. The magnesium content in all samples increased gradually from the early stage of fermentation. The microstructure showed disintegration appearance of middle lamella and cell wall during fermentation period.

      • KCI등재
      • KCI등재

        Effects of I- and W-Phases Under Identical Conditions on Microstructure and Mechanical Properties of As-Cast Mg–Zn–Y Alloys at Room and Elevated Temperatures

        Young‑Gil Jung,Wonseok Yang,Jae Ik Hyun,Shae K. Kim,Hyunkyu Lim,Do Hyang Kim 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

        Three alloys (Mg–6Zn–1.2Y, Alloy I; Mg–3.65Zn–1.65Y, Alloy II; and Mg–4.3Zn–1.4Y, Alloy III) with same volume fractionand grain size were designed to evaluate the effects of the I-phase (Mg3Zn6Y) and W-phase (Mg3Zn3Y2), which are themajor phases in Mg–Zn–Y alloys, on the mechanical properties. The tensile strength of Alloy I with the I-phase at roomtemperature was the highest among the tested alloys because the coherent interface between the I-phase and the α-Mg phasewas more resistant to cracking than the incoherent interface between the W-phase and the α-Mg phase. A cross-sectionalmicrostructure analysis of a sample that was tensile-tested at 423 K revealed that the morphology of the I-phase remainedrelatively stable. In contrast, the W-phase was broken and fragmented during the tensile test at 423 K because it had higherbrittleness under the test conditions. Therefore, the tensile and creep properties of Alloy I at 423 K were better than thoseof Alloys II and III containing the W-phase. According to the results, the I-phase in the Mg-Zn-Y alloy was more beneficialto the mechanical properties at room temperature and 423 K than the W-phase.

      • 제초제(propanil. butachlor) 저항성 잡초 선발 방법에 관한 연구

        정성엽,김영미,박재현,이재현,김학윤,이인중,신동현,김길웅 경북대학교 농업과학기술연구소 1999 慶北大農學誌 Vol.17 No.-

        This study was conducted to develop a simple selection method for herbicide-resistance weeds. Two methods, designated "seedling method" and "stem node method" were employed for screening of barnyardgrass against propanil and butachlor. In the seedling method, shoot and root growth of barnyardgrass were significantly inhibited at quarter of the recommended herbicide rate, while in the stem node method, the similar inhibition was obtained at half of the recommended rate. Thus, it was concluded that the seedling method is more simple and quick method to evaluate response of barnyardgrass to propanil and butachlor compared to stem node method.

      • KCI등재

        나노 충전제 함량에 따른 복합레진의 표면 미세경도 차이

        정영정,김연재,김정욱,이상훈,김종철,한세현,장기택 大韓小兒齒科學會 2005 大韓小兒齒科學會誌 Vol.32 No.1

        최근에 개발된 나노 충전제를 microhybrid 복합레진에 첨가할 때, 나노 충전제 함량이 중합에 미치는 영향을 조사하기 위해, 실험적으로 나노 충전제의 함량을 다르게 제작한 복합레진에서 광중합 후 미세경도를 측정, 분석하여 다음과 같은 결론을 얻었다. 1. 나노 충전제의 함량이 2%, 3%인 군은 0%, 1%인 군에 비해 중합된 면의 미세경도가 유의하게 높았으나(p<0.01), 그 차이는 크지 않았다. 2. 나노 충전제의 함량이 높을수록 레진 시편의 하면에서의 미세경도는 증가하였으며, 나노 충전제의 함량이 0%, 1%, 2%간에, 0%, 1%, 3%간에 유의한 차이가 있었고(p<0.01), 2%와 3%간에는 차이가 없었다(p<0.05). 3. 레진 시편의 상면과 하면의 미세 경도 차이는 나노 충전제 함량이 높을수록 감소하였으며, 나노 충전제의 함량이 0%, 1%, 2%간에, 0%, 1%, 3%간에 유의한 차이가 있었고(p<0.01), 2%와 3%간에는 차이가 없었다(p<0.05). The objective of this study was to evaluate the effects of nanofiller content on the microhardness and polymerization of experimental microhybrid composites. The nanofiller contents in the experimental composites were varied (0%, 1%, 2%, 3%), while the total filler content remained constant as 76 %wt. We obtained the following results: 1. The microhardness of the top surface for the 2%, 3% nanofilled microhybrid composites were significantly higher than those for the 0%, 1% nanofilled composites (p<0.05), but the difference was not great. 2. The microhardness of the bottom surfaces significantly increased with an increase in the nanofiller level (p<0.05), except between the 2% and 3% nanofilled groups (p>0.05). 3. As the nanofiller level increased, the difference beween microhardness of top and bottom surfaces significantly decreased (p<0.05), except between 2% and 3% nanofilled groups (p>0.05).

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