Conceptual Study for Tissue-Regenerative Biodegradable Magnesium Implant Integrated with Nitric Oxide-Releasing Nanofi bers

Jin‑Kyung Jeon,Hyunseon Seo,Jimin Park,Soo Ji Son,Yeong Rim Kim,Eun Shil Kim,Jong Woong Park,Woong‑Gyo Jung,Hojeong Jeon,Yu‑Chan Kim,Hyun‑Kwang Seok,Jae Ho Shin,Myoung‑Ryul Ok 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

The excessive initial corrosion rate of Mg is a critical limitation in the clinical application of biodegradable Mg implantsbecause the device loses its fi xation strength before the fractured bone heals. This study suggests a new approach to overcomethis hurdle by accelerating tissue regeneration instead of delaying the implant biodegradation. As angiogenesis is anessential process in early bone regeneration, a Mg implant coated with electrospun nanofi bers containing nitric oxide (NO),which physiologically promotes angiogenesis, is designed. The integrated device enables adjustable amounts of NO to bestored on the NO donor-conjugated nanofi ber coating, stably delivered, and released to the fractured bone tissue near theimplanted sites. An in vitro corrosion test reveals no adverse eff ect of the released NO on the corrosion behavior of the Mgimplant. Simultaneously, the optimal concentration level of NO released from the implant signifi cantly enhances tube networkformation of human umbilical vein endothelial cells without any cytotoxicity problem. This indicates that angiogenesis canbe accelerated by combining NO-releasing nanofi bers with a Mg implant. With its proven feasibility, the proposed approachcould be a novel solution for the initial stability problem of biodegradable Mg implants, leading to successful bone fi xation.

Variation of Bird community and Habitat use after Developing Hangang river Ecological Learning Center

Paik, In-Hwan,Jin, Seon-Deok,Jeon, Byung-Seon,Yu, Jae-Pyoung,Park, Chi-Young,Paek, Woon-Kee national science museum of korea 2010 Journal of Korean nature Vol.3 No.4

The Hangang (Han River) Ecological Learning Center is a river ecosystem park which was completed in December of 2002. The river ecosystem park was created based on the understanding of the problems of standard park-formed river which centers around convenient facilities instead of on the wish to accentuate the innate unique characteristics of a river. Therefore, the study was conducted in order to analyze the changes and habitation usage of the avifauna in the Hangang Ecological Learning Center to provide basic information for the improvement of bird species diversity in an ecosystem park. The study was conducted in July and October of both 2003 and 2005 to study the avian colonies of the same time period, and the habitat usage of four different areas were examined. Main dominant species includes species which preferred waterside and grassland, and 2005 showed higher levels of species, bird count and number of migratory birds. Furthermore, among the four regions used as habitats, the confluence region showed the highest level of increase, and this is predicted to have caused by the shallow depth of the confluence and the stability of the waterside plant colonies.

대량의 각혈로 사망한 장티푸스 1예

한상우,유진홍,권순석,김성훈,박지찬,홍은정,최경성,박용완,장준희,안지원,박유경,강지영,박상미,신완식 대한감염학회 2004 감염과 화학요법 Vol.36 No.5

We experienced a 25 year-old male patient with typhoid fever complicated with massive hemoptysis. Pulmonary complication in typhoid fever is very rare and to our knowledge, there has been no report of hemoptysis as a main cause of death with this disease. We herein report a rare case of typhoid fever.

정신분열병 환자에서 얼굴 영상의 작동기억 장애 : 기능자기공명영상연구

이창욱,김태석,주라형,박주미,박여진,김종진,전신수,배치운,김정진,이수정,이철,백인호 大韓神經精神醫學會 2005 신경정신의학 Vol.44 No.2

Objectives : Impaired processing of facial information is one of the broad ranges of cognitive deficits seen in patients with Schi-zophrenia. We aimed to elucidate the differences in brain activities involved in the process of facial working memory between schizophrenic patients and healthy comparison subjects. Methods : Twelve patients with schizophrenia were recruited along with twelve demographically matched healthy volunteers as a comparison group. Functional magnetic resonance imaging (fMRI) was used to assess cortical activities during the Perfor-mance of a 2-back working memory paradigm using images of neutral faces as mnemonic content. Rcsults : The patient group performed the tasks with reduced accuracy. Group analysis revealed that the left fusiform gyrus, the right superior frontal gyrus, the bilateral middle frontal gyri/insula, the left middle temporal gyrus, the precuneus, the quadrangular lobules and the vermis of cerebellum showed decreased cortical activities in the patient group. On the other hand, an increased level of activation in the lateral prefrontal cortex and the pahetal lobule was observed from the patient group, all in the right hemisphere. Conulusion : A decreased level of activity in the left fusiform gyrus among the patient group implicates inefficient processing of facial information. An increased level of activation in prefrontal and parietal neural networks from the patient group confirms earlier findings on the impaired working memory of patients with schizophrenia.

양방향 요소제거법을 이용한 신뢰성 기반 최적설계

유진식,박재용,황승민,임민규,오영규,한석영 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

This research presents a Reliability-Based Topology Optimization (RBTO) using Bi-directional Evolutionary Structural Optimization (BESO). An actual design involves uncertain conditions such as material property, operational load and dimensional variation. Deterministic Topology Optimization (DTO) is obtained without considering of uncertainties related to the uncertainty parameters. However, RBTO involves evaluation of probabilistic constraints, which can be done in two different ways, the reliability index approach (RIA) and the performance measure approach (PMA). The reliability index approach (RIA) and the performance measure approach (PMA) are adopted to evaluate the probabilistic constraints. In order to apply the BESO method to the RBTO, sensitivity number is defined as the change in the reliability index due to the addition or the removal of the ith element. In the BESO, a mesh-independency filter using nodal variables is used to remove the checkerboard patterns. The optimal topologies of RIA and PMA are obtained very similarly. It is shown that RBTO based on BESO can be effectively applied from the presented examples.

폐구리염화물용액의 분무열분해반응에 의한 생성분말의 특성에 관한 연구

박희범,최재권,한진아,유재근 호서대학교 반도체제조장비국산화연구센터 2001 반도체장비학술심포지움 Vol.2001 No.-

본 연구의 목적은 폐 구리염화물 용액을 원료로 사용하여 분무열분해 공정에 의해 평균입도가 1 ㎛ 이하이며 입도분포가 균일하고 치밀한 조직을 나타내는 미립의 구리산화물 분말을 제조하는데 있다.또한 본 연구에서는 분무열분해 공정에 의해 생성되는 분말의 특성에 영향을 미치는 반응 온도, 원료용액의 유입속도, 분위기기체 및 공기의 유입속도, nozzle tip 크기 및 원료용액의 농도 등의 반응인자들의 영향을 검토하였다.

일부 인쇄회로기판 납땜근로자들의 눈, 호흡기, 피부의 증상에 대한 조사연구

유재영,우극현,김진석,함정오,최태성,하봉구,정상재,박신구,김일룡 大韓産業醫學會 2001 대한직업환경의학회지 Vol.13 No.4

목적 : 이 연구는 납점작업자를 대상으로 납점작업으로 유발될 가능성이 높은 눈, 호흡기, 피부 등의 증상호소율 및 노출강도에 따른 관련성을 파악하기위해 수행되었다. 방법 : 연구참가자 146명중 연구목적에 적합한 20명을 제외한 126명을 대상으로 '눈이 가렵고 충혈됨', '코가 가렵거나 파가움', '재채기', '콧물'. '코막힘' , '목이 따끔거림' , '목에 무언가가 걸려있는것 같음' , '갑자기 연속적인 기침을 함' , '운동 시에 다른 사람에 비해 숨이 가쁨', '숨을 쉴 때 쌕쌕하는 소리가 남', '가래가 끓음', '손이나 안면에 가려움을 느낌' , '안면에 여드름이 날' '손이나 안면에 붉은 반점이 남' 등 14가지 증상에 대한 경험유무와 혈중연농도, 납점작업의 건강위험요인에 대한 지식상태 등을 조사하였다. 결과 : 조사된 14가지의 증상 중, '갑자기 연속적인 기침을 함'이 하루 납점시간 4시간 이상인 군아서 4시간 미만인 군보다 유의하게 증상호소율이 높았으며, 다른 증상의 경우 하루 납땜시간에 따라 유의한 결과를 보이지 않았다. 납땜작업의 건강위험요인에 대한 질문에 12.8 %가 플럭스에 의한 건강위험을 지적하였다. 전체 대상자의 평균 혈중연농도는6.05 rg/dL였으며, 히고치는 15.50 rg/dL이었다.결론 : 납땜작업자에게 호흡기 증상의 위험이 높을 가능성이 있으며, 납땜작업의 건강위험에 대한추가적인 연구와 납점작업자들을 대상으로 납점작업에 의해 유발될 수 있는 건강장해에 대한 적극적인교육 및 홍보활동을 필요로 한다. Objectives : This study was conducted to evaluate the prevalence of ocular, respiratory and skin symptoms among solderers and to investigate the relationship between symptom prevalence and exposure intensity. Methods : We analyzed 126 eligible participants out of a population of 146 male solder-ers who completed the symptom questionnaires. Fourteen symptoms including 'itchy and red eyes', 'itchy or prickly nose', 'sneezing', 'rhinorrhea', 'blocked nose', 'prickly throat', 'foreign body sensation in throat', 'sudden bouts of coughing', 'exertional breathlessness', 'wheezing', 'sputum production', 'itchy face or hands', 'acneiform erup-tions on the face' and 'red spots on the face or hands' were contained. Blood lead levels of all the 126 participants were tested and the participants' own assessments of the health risk of soldering were collected. Results : Of the 14 investigated symptoms, 'sudden bouts of coughing' was significantly more prevalent in solderers who worked 4 hours or more a day than those who worked less than 4 hours a day, as for the other symptoms, there were no significant differences in the prevalences related to daily soldering hours. 2.8% of the solderers considered the risk of flux exposure to be serious. The mean blood lead bevel was 6.05 μg/dL (maximum 15.50 μg/dL). Conclusions : Soldering may increase the risk of respiratory symptoms. Further invert tigations on the hazards of soldering processes are warranted and solderers should be educarted on these hazards.

거시적 관점에서의 임금과 생산성의 관계에 대한 연구 : 우리 나라 제조업을 중심으로

박성준,오유진 한국노동경제학회 2001 勞動經濟論集 Vol.24 No.3

본 연구는 Geweke의 선형 피드백 방법과 Sims의 충격 반응(impulse response) 방법을 사용하여 1971년 1분기부터 2000년 3분기까지의 임금과 생산성 자료를 이용하여 임금과 생산성 간의 관계를 규명함으로써 우리 나라 제조업에 있어서의 임금결정방식을 살펴보았다. 특히 경제위기 이후 실업률이 급등한 상황에서 임금결정방식에서는 어떠한 변화가 일어났는지를 살피기 위해 자료를 경제위기 이전과 경제위기를 포함한 전 기간으로 나누었다. 그 결과 경제위기 이전까지는 생산성 향상이 임금 증가를 가져오고 또한 임금 상승이 생산성 향상으로 이어지는 순환관계를 보여 우리 제조업에서의 임금결정방식은 노동시장 균형이론과 이의 대체이론 모두를 지지하는 것으로 나타났다. 그러나 경제위기를 포함한 전 기간에서는 생산성 향상은 임금의 증가를 가져왔으나 임금은 생산성 상승과 무관하게 나타나, 경제위기 이후 우리 제조업에서의 임금결정방식은 노동시장 균형이론만이 반영되었다고 유추 해석되어진다. We focus on the relationship between the wage and the productivity in the Korean manufacturing industry over the period from the 1971 year to the 2000 year by using the Geweke's linear feedback method and the impulse response method. And we divide the whole period into the 1971-before the financial crisis and the 1971-2000 including the after the financial crisis to study the change of the relationship between the wage and the productivity after the financial crisis. The results are the followings; The productivity has the large influence on the wage positively, so that the improvement of the productivity boosts the wage and the vice versa in the before financial crisis period. It means that both the conventional wage setting theory and the alternative wage theory(efficiency wage and union theory) exist in the manufacturing industry. However, there exist only the conventional wage setting theory in the whole period.

포도재배용 봉지제조 기술개발 : 종이의 구조적 특성이 광 투과에 미치는 영향

유병철,이진호,이장호,박종문 충북대학교 첨단원예기술개발연구센터 2000 연구보고서 Vol.5 No.-

유해화학물질의 계통분석

박성우,박유신,이진훈,김남이,김유나,임미애,이상기,유재훈,진광호,신호상,노동석 內務部 國立科學搜査硏究所 2001 國立 科學 搜査 硏究所 年報 Vol.33 No.-