• 한국콘텐츠학회논문지
• /
• 제11권3호
• /
• pp.477-486
• /
• 2011

본 논문에서는 컴퓨터 사용 시간과 시력 저하 관계를 분석했다. 우선 첫째로, 조사에 참여한 학생들을 성별, 학년, 시력과 안경 착용으로 인구학적 특성에 따라 분류 하였다. 설문은 컴퓨터 사용 시간, 시력 저하의 요인들, 그리고 컴퓨터 사용 목적에 관한 질문들을 하였다. 학생들의 연간 시력 변화와 시력 변화의 원인에 대해서 교차 분석한 결과, 설문에 참가한 165명의 학생 중 63.6%가 한 해 동안 시력이 나빠졌다. 컴퓨터 사용시간과 시력 저하 상관관계를 나타내기 위해 회귀 분석한 결과 일일과 주간 컴퓨터 사용에서는 시력저하를 나타냈고, 년 컴퓨터 사용에서는 시력저하를 나타내지 않았다. 또한 독립 표본 T검정으로 안경 착용과 미착용자의 컴퓨터 사용 시간과 시력 저하를 분석한 결과 일일과 주간 컴퓨터 사용에서는 시력저하를 나타냈고, 년 컴퓨터 사용에서는 시력저하를 나타내지 않았다. 그런데 안경 미 착용자가 안경 착용자에 비해서 시력 저하를 더 나타냈다. 본 논문에서는 24.5%의 학생들이 컴퓨터 사용으로 시력저하를 나타냈다. 컴퓨터 사용 용도의 빈도분석 결과에서는 컴퓨터 게임이 36.4%로 가장 많았고, 그 다음으로 학습목적이 32.1% 나타났다. 본 논문에서는 컴퓨터 사용 시간과 시력 저하의 요인 분석을 통해 컴퓨터 사용 시간이 시력저하에 상관관계가 있음을 나타낸다. 따라서 학생들의 컴퓨터 사용에 대한 학부모님들의 관심이 필요하다.

• Journal of Periodontal and Implant Science
• /
• 제31권2호
• /
• pp.277-285
• /
• 2001

Periodontal disease is characterized by inflammation and subsequent loss and/or damage to tooth-supporting tissues such as bone, cementum,and periodontal ligament. Periodontal ligament and cementum are the key tissues in the initial process of regeneration following periodontal disease. Therefore, studies on cementoblasts, which form cementum are emphasized. It is still unclear which cells cementoblast differentiate from. This study was conducted under the hypothesis that PDL fibroblast can differentiate into either cementoblast or osteoblast depending on the conditions of surrounding tissue. Clinically, with excessive traction force of orthodontic appliances or excessive occlusion hypercementosis is observed, and this has been confirmed histologically. Consequently, activation of cementoblast can be expected in rats when mechanical stimuli are given to PDL fibroblast. Therefore, the purpose of this article is to prove that PDL fibroblast differentiates into cementoblast in rats under mechanical stimuli using histologic and molecular methods. In this study, twenty rats were given hard diet. Ten of them were sacrificed after 1 week, and the others were sacrificed after two weeks. Slides were made from tooth specimen, and they were studied under the microscope. In addition, PDL fibroblast and cementum from the extracted teeth were analyzed with Northern blotting. In histologic examination, as time passed, PDL fibroblast migrated to the dentin side, differentiated into cementoblast, and formed new cementum. In Northern blotting, it was found that mRNA expression of cementoblast-specific proteins such as BSP, OC, OPN, and type I collagen were more prominent in rats sacrificed after 2 weeks of hard-diet than rats sacrificed after 1 week. From these findings we can conclude that PDL fibroblast can differentiate into cementoblast under mechanical stimuli. We think that 'Rat Models' used in this study will be beneficial to future studies regarding cementoblast.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권2호
• /
• pp.437-442
• /
• 2015

Aim: To establish a pancreatic cancer stem cell model using human pancreatic cancer cells in nude mice to provide a platform for pancreatic cancer stem cell research. Materials and Methods: To establish pancreatic cancer xenografts using human pancreatic cancer cell line SW1990, nude mice were randomly divided into control and gemcitabine groups. When the tumor grew to a volume of $125mm^3$, they treated with gemcitabine at a dose of 50mg/kg by intraperitoneal injection of 0.2ml in the gemcitabine group, while the mice in control group were treated with the same volume of normal saline. Gemcitabine was given 2 times a week for 3 times. When the model was established, the proliferation of pancreatic cancer stem cells was observed by clone formation assay, and the protein and/or mRNA expression of pancreatic stem cell surface markers including CD24, CD44, CD133, ALDH, transcription factors containing Oct-4, Sox-2, Nanog and Gli, the key nuclear transcription factor in Sonic Hedgehog signaling pathway was detected by Western blot and/or RT-PCR to verify the reliability of this model. Results: This model is feasible and safe. During the establishment, no mice died and the weight of nude mice maintained above 16.5g. The clone forming ability in gemcitabine group was stronger than that of the control group (p<0.01). In gemcitabine group, the protein expression of pancreatic cancer stem cell surface markers including CD44, and ALDH was up-regulated, the protein and mRNA expression of nuclear transcription factor including Oct-4, Sox-2 and Nanog was also significantly increased (P<0.01). In addition, the protein expression of key nuclear transcription factor in Sonic Hedgehog signaling pathway, Gli-1, was significantly enhanced (p<0.01). Conclusions: The pancreatic cancer stem cell model was successfully established using human pancreatic cancer cell line SW1990 in nude mice. Gemcitabine could enrich pancreatic cancer stem cells, simultaneously accompanied by the activation of Sonic Hedgehog signaling pathway.

• 한국환경생태학회지
• /
• 제26권6호
• /
• pp.960-969
• /
• 2012

무등산도립공원 주요 거점의 시간대별 탐방객 이동패턴을 파악하여 관리방안을 제안하기 위해 증심사지구, 원효사지구, 중머리재 등 주요 지점에서 계절별로 3일씩, 오전 7시부터 오후 7시까지 출입하는 탐방객 수를 조사하였다. 조사결과 무등산도립공원 주요 출입구인 증심사지구와 원효사지구에서는 대부분 오전 9시부터 오후 2시 사이에 입장하였고, 오전 10시에서 11시 사이에 입장객 수가 가장 많았다. 퇴장시간은 대부분 오전 12시부터 오후 5시 사이였으며, 피크시간은 오후 2시부터 4시 사이었다. 중머리재를 방문하는 탐방객들은 대부분 오전 11시에서 오후 3시 사이에 중머리재를 경유하여 장불재나 중봉방향으로 등산하거나 증심사지구나 원효사지구로 하산하였는데 오전 11시부터 오후 1시까지가 피크시간 이였다. 한편, 요일과 계절에 따른 시간대별 이동 패턴에는 뚜렷한 경향이 나타나지 않았다. 공원자원 보전과 탐방만족도 증진을 위해서 탐방객이 집중되는 장소와 시간을 중심으로 탐방안내, 캠페인, 훼손지복원 등 집중관리가 필요하다.

• 한국시뮬레이션학회논문지
• /
• 제23권4호
• /
• pp.31-39
• /
• 2014

계절적 유행성 독감은 매년 전 세계적으로 300만-500만 명이 감염되어 25만-50만 명이 사망에 이르는 무서운 질병이다. 유행성 독감에 대한 통제를 강화하기 위해 독감의 유행을 실시간으로 감시하기 위한 연구들이 제안되고 있다. 우리나라의 질병관리본부는(CDC)는 인플루엔자에 대한 임상 자료를 1주 단위로 발표하고 있으며 질병의 유행과 1-2주 정도의 보고 시차가 존재한다. 조기에 독감의 유행을 감지하기 위해 비임상적 자료(뉴스 리포트, 소셜 미디어)의 검색 정보를 활용하여 유행성 독감 발생을 효과적으로 대비하기 위한 연구들이 최근 이루어지고 있다. 비임상적 자료의 수집은 적은 비용으로 거의 실시간으로 이루어질 수 있는 이점이 있다. 본 연구는 네이버 검색엔진이 제공하는 PC와 모바일 키워드 정보를 활용하여 우리나라의 유행성 독감 활동을 감지하는 회귀모형을 개발하고자 한다. 이를 위해 문헌연구를 통하여 인플루엔자 의사분율(ILI)과 높은 상관성을 가질 것으로 예상되는 키워드를 20개 선정하고 키워드와 ILI와의 관계를 로지스틱 회귀모형과 다중회귀모형으로 가정하고 ILI를 예측하였다. 모형적합성 측면에서 다중회귀모형이 로지스틱모형보다 우수하였으며 모바일-기반 회귀모형이 PC-기반 회귀모형보다 ILI 퍼센티지를 추정하는데 우월한 결과를 보이고 있다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제33권4호
• /
• pp.605-614
• /
• 2020

Objective: This study was conducted to determine the effects of stale maize on growth performance, immunity, intestinal morphology, and antioxidant capacity in broilers. Methods: A total of 800 one-day-old male Arbor Acres broilers (45.4±0.5 g) were blocked based on body weight, and then allocated randomly to 2 treatments with 20 cages per treatment and 20 broilers per cage in this 6-week experiment. Dietary treatments included a basal diet and diets with 100% of control maize replaced by stale maize. Results: The content of fat acidity value was higher (p<0.05) while the starch, activities of catalase and peroxidase were lower (p<0.05) than the control maize. Feeding stale maize diets reduced (p<0.05) average daily feed intake (ADFI) throughout the experiment, feed conversion ratio (FCR) during d 0 to 21 and the whole experiment as well as relative weight of liver, spleen, bursa of Fabricius and thymus (p<0.05) on d 21. Feeding stale maize diets decreased jejunum villus height (VH) and VH/crypt depth (CD) (p<0.05) on d 21 and 42 as well as ileum VH/CD on d 42. The levels of immunoglobulin G, acid α-naphthylacetate esterase positive ratios and lymphocyte proliferation on d 21 and 42 as well as lysozyme activity and avian influenza antibody H₅N₁ titer on d 21 decreased (p<0.05) by the stale maize. Feeding stale maize diets reduced (p<0.05) serum interferon-γ, tumor necrosis factor-α, interleukin-2 on d 21 and interleukin-6 on d 21 and 42. Broilers fed stale maize diets had lower levels of (p<0.05) total antioxidative capacity on d 42, superoxide dismutase and glutathione peroxidase on d 21 and 42, but higher (p<0.05) levels of malondialdehyde on d 21 and 42. Conclusion: Feeding 100% stale maize decreased ADFI and FCR, caused adverse effects on immunity and antioxidant function and altered intestinal morphology in broilers.

• 한국ITS학회 논문지
• /
• 제18권5호
• /
• pp.64-78
• /
• 2019

본 논문은 공간 상관성을 고려하여 서울의 택시통행에 영향을 미치는 요인을 분석한 것으로 택시의 GPS 자료를 이용하였다. 먼저 이들 자료를 이용하여 택시통행의 평균 통행시간, 평균 통행거리, 시공간적 분포 등의 통행특성을 분석하였다. 분석결과, 상당수의 택시통행이 평일 오전 첨두(8-9시)와 심야(0-1시) 시간대에 집중하는 것으로 나타났으며, 평균 통행거리와 통행시간은 각각 5.9km와 13분으로 나타났다. 이는 택시가 주로 단거리 통행수단이나 심야에 대중교통의 대체수단으로 활용되고 있음을 보여주고 있다. 다음으로 Moran's I 검정을 통해 교통존 기반의 택시통행들이 공간적으로 상관성이 있음을 규명하였다. 따라서 이를 고려한 택시통행에 대한 공간회귀모형(공간시차모형과 공간오차모형)을 추정하였으며, 인구사회 변수(가구수, 고령자수, 여성인구비, 자동차대수 등), 교통서비스 변수(지하철역수, 버스 정류장수 등), 토지이용 변수(인구밀도, 고용밀도, 주거면적 등) 등을 독립변수로 고려하였다. 모형분석 결과 이들 변수들이 통계적으로 유의하게 택시통행에 영향을 미치는 것으로 나타났다.

• Advances in nano research
• /
• 제13권6호
• /
• pp.575-585
• /
• 2022

Due to its biofilm formation and colonization of the osteocyte-lacuno canalicular network (OLCN), Staphylococcus aureus (S.aureus) implant-associated bone infection (SIABI) is difficult to cure thoroughly, and may occur recurrently subsequently after a long period dormant. It is essential to explore an alternative therapeutic strategy that can eradicate the pathogens in the infected foci. To address this, the polymethylmethacrylate (PMMA) bone cement and Fe3O4 nanoparticles compound cylinder were developed as implants based on their size and mechanical properties for the alternative magnetic field (AMF) induced thermal ablation, The PMMA mixed with optimized 2% Fe₃O₄ nanoparticles showed an excellent antibacterial efficacy in vitro. It was evaluated by the CFU, CT scan and histopathological staining on a rabbit 1-stage transtibial screw model. The results showed that on week 7, the CFU of infected soft tissue and implants, and the white blood cells (WBCs) of the PMMA+2% Fe₃O₄+AMF group decreased significantly from their controls (p<0.05). PMMA+2% Fe₃O₄+AMF group did not observe bone resorption, periosteal reaction, and infectious reactive bone formation by CT images. Further histopathological H&E and Gram Staining confirmed there was no obvious inflammatory cell infiltration, neither pathogens residue nor noticeably burn damage around the infected screw channel in the PMMA+2% Fe₃O₄+AMF group. Further investigation of nanoparticle distributions in bone marrow medullary and vital organs of heart, liver, spleen, lung, and kidney. There were no significantly extra Fe₃O₄ nanoparticles were observed in the medullary cavity and all vital organs either. In the current study, PMMA+2% Fe₃O₄+AMF shows promising therapeutic potential for SIABI by providing excellent mechanical support, and promising efficacy of eradicating the residual pathogenic bacteria in bone infected lesions.

• Animal Bioscience
• /
• 제35권10호
• /
• pp.1575-1584
• /
• 2022

Objective: An experiment was conducted to evaluate the effects of partially replacing soybean meal (SBM) with sunflower meal (SFM) with added exogenous multienzymes (MEs) on various biological parameters in broilers. Methods: One week-old, 400 broiler chicks were randomly divided into four treatments (control, 3SFM, 6SFM, and 9SFM) with 5 replicates/treatment (20 chicks/replicate). Control diet was without SFM and MEs, while diets of 3SFM, 6SFM, and 9SFM treatments were prepared by replacing SBM with SFM at levels of 3%, 6%, and 9%, respectively, and were supplemented with MEs (100 mg/kg). Feeding trial was divided into grower (8 to 21 day) and finisher phases (22 to 35 day). External marker method was used to measure the nutrient digestibility. At the end of trial, twenty birds (one birds per replicate) with similar body weight were slaughtered for samples collection. Results: No significant effect of dietary treatments was found on all parameters of growth performance and carcass characteristics, except relative weight of bursa. Weight (25.0 g) and length (15.80 cm) of duodenum were significantly (p<0.05) higher in 3SFM than control. Lowest (p<0.05) villus height/crypt depth ratio was found in 3SFM and 9SFM than control. Most of meat quality parameters remained unaffected, however, highest pH of breast meat (6.16) and thigh meat (6.44) were observed in 9SFM and 3SFM, respectively. Lowest (p<0.05) cook loss of thigh meat was found in 6SFM (31.76%). Ileal digestibility of crude protein was significantly (p<0.05) higher in 3SFM (72.35%) than control (69.46%). In addition, amylase (16.87 U/mg) and protease (85.18 U/mg) activities were significantly (p<0.05) higher in 3SFM than control. However, cecal microbial count remained unaffected. Conclusion: Partial replacement (up to 9%) of SBM with SFM, with added MEs can help to improve the nutrient digestibility, intestinal morphology, and digestive enzyme activities without affecting cecal microbial count and growth performance in broilers.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권4호
• /
• pp.2621-2626
• /
• 2013

Background: To review the peer reviewed literature on the psychological aspects of the prostate cancer experience of men in Asia. Materials and Methods: Medline and PsycINFO, CINAHL, ProQuest, and Web of Science (1999 - November Week 4, 2012) were searched. Inclusion criteria were: included men with prostate cancer and/or their partners or caregivers who identify as Asian recruited in an Asian country; and assessed health-related quality of life, psychological and social adjustment relating to prostate cancer and published in English after $1^{st}$ January 1999 and prior to $30^{th}$ November, 2012. Study aims; design; quality; level of evidence, and key results were assessed. Results: 43 articles met all inclusion criteria and were retained for initial review. Of these most focussed on health-related QOL with only five evidence Level IV studies from Japan and Taiwan including a specific psychological focus. Of these, one was a cross-sectional case control study; three were cross-sectional descriptive quantitative designs; one was a cross-sectional descriptive qualitative study. From the data available, a substantive sub group of men with prostate cancer (approximately one third) in these countries experience clinically high psychological distress and decision regret. Conclusions: Research on the psychological needs of men with the increasingly prevalent condition of prostate cancer in Asian countries is scant with only a small number of low level evidence descriptive studies identified. Future research to underpin the development and evaluation of effective and culturally relevant psychological and supportive care interventions for such men is urgently needed.