• 대한의용생체공학회:의공학회지
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• 제31권4호
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• pp.292-301
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• 2010

To restore visual sensation of blind patients, we have proposed a fully implantable retinal prosthesis comprising an three dimensionally (3D) stacked retinal chip for transforming optical signal to electrical signal, a flexible cable with stimulus electrode array for stimulating retina cells, and coupling coils for power transmission. The 3D stacked retinal chip is consisted of several LSI chips such as photodetector, signal processing circuit, and stimulus current generator. They are vertically stacked and electrically connected using 3D integration technology. Our retinal prosthesis has a small size and lightweight with high resolution, therefore it could increase the patients` quality of life (QOL). For realizing the fully implantable retinal prosthesis, we developed a retinal prosthesis module comprising a retinal prosthesis chip and a flexible cable with stimulus electrode array for generating optimal stimulus current. In this study, we used a 2D retinal chip as a prototype retinal prosthesis chip. We fabricated the polymide-based flexible cable of $20{\mu}m$ thickness where 16 channels Pt stimulus electrode array was formed in the cable. Pt electrode has an impedance of $9.9k{\Omega}$ at 400Hz frequency. The retinal prosthesis chip was mounted on the flexible cable by an epoxy and electrically connected by Au wire. The retinal prosthesis chip was cappted by a silicone to pretect from corrosive environments in an eyeball. Then, the fabricated retinal prosthesis module was implanted into an eyeball of a rabbit. We successfully recorded electrically evoked potential (EEP) elicited from the rabbit brain by the current stimulation supplied from the implanted retinal prosthesis module. EEP amplitude was increased linearly with illumination intensity and irradiation time of incident light. The retinal prosthesis chip was well functioned after implanting into the eyeball of the rabbit.

• The Journal of Korean Physical Therapy
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• 제12권1호
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• pp.41-47
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• 2000

BACKGROUND AND PURPOSE. The purpose of this study is to investigate the effect of the disturbed vision on the gait distance parameters on the healthy young population. SUBJECTS. Twenty four healthy college aged individuals are randomly assigned to both a condition with a strobe light and the other condition without a strobe light. METHODS. The instrumentation used for gait analysis is the GaitRite electronic walkway system with a personal IBM computer. The examiner naked all the subjects to walk 6 times on the gait mat without the strobe light and. 6 times on the mat with the strobe light. The first 4 trials were practice and the last two trials were recorded in both conditions. The gait parameters analyzed were as follows : velocity, cadence, step length, and heel to heel base of support. RESULTS. Paired samples t-test used for this study did not found any significant differences between the two conditions because the p-values that were analyzed on the experiment were Utter than 0.05. The gait parameters that were analyzed included cadence, velocity, left and right heel to heel base of support, and left and right step length. DISCUSSION AND CONCLUSION. Based on this population, the condition of disturbed vision via the effect of the strobe light was not significantly challenging to compromise the body's sensory systems. However, in the elderly population, these systems can undergo age related changes. Visual changes rapidly decline in people 60 to 80 years of age and changes in the vestibular system include $20-40\%$ reduction in hair cells.

• 한국인터넷방송통신학회논문지
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• 제12권1호
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• pp.75-81
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• 2012

고해상도 위성영상에 내재된 도로 영역의 추출에 있어서 이진화, 잡음 제거, 색처리 등의 전처리 작업에 의해서 추출된 도로 후보 영역에 대한 도로 영역 식별 작업은 가장 중요한 과정이다. 따라서 본 논문에서는 전처리 작업에 의해서 추출된 도로 후보 영역에 대해서 대뇌 시각영역에서 발견되는 신경 세포(Neuron cell)의 방향-선택적 인지 기능을 계산 모델화한 공간필터(Orientation-selective spatial filter)를 적용하여 도로 영역을 식별하는 새로운 방법을 제안한다. 제안하는 방법은 전처리 결과 고립된 연결 성분으로 라벨링 된 각각의 도로후보 영역에 대해서 신경 세포형 방향 필터를 적용한 후, 강한 방향 성분이 인지된 영역을 도로 영역으로 식별한다. 제안한 방법의 성능 평가를 위해서는 위성영상으로부터 추출된 도로 후보 영역에 대해서 도로, 비도로 부류의 혼동 행렬(Confusion matrix)을 이용한 식별 정확 및 오류율을 측정하여 보인다. 실험 결과, 본 논문에서 제안한 방향 선택적 필터 기반의 방법은 추출된 도로 후보 영역에 대해서 92% 이상의 도로 식별 정확성을 보였다.

• Journal of Periodontal and Implant Science
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• 제36권1호
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• pp.265-272
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• 2006

Dental plaque, a biofilm consisting of more than 500 different bacterial species, is an etiological agent of human periodontal disease, It is therefore important to characterize interactions among periodontopathic microorganisms in order to understand the microbial pathogenesis of periodontal disease. Previous data have suggested a synergistic effect of tow major periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia in the periodontal lesion. In the present study, to better understand interaction between P. gingivalis and T. forsythia, the coaggregation activity between these bacteria was characterized. The coaggregation activity was observed by a direct visual assay by mixing equal amount (1 ${\times}$ $10^9$)of T. forsythia and P. gingivaJis cells. It was found that the first aggregates began to appear after 5-10 min, and that the large aggregates completely settled within 1 h. Electron and epifluorescence microscopic studies confirmed cell-cell contact between two bacteria. The heat treatment of P. gingivalis completely blocked the activity, suggesting an involvement of a heat-labile component of P. gingivalis in the interaction. On the other hand, heat treatment of T. forsythia significantly increased the coaggregation activity; the aggregates began to appear immediately. The coaggregation activity was inhibited by addition of protease, however carbohydrates did not inhibit the activity, suggesting that coaggregation is a protein-protein interaction. The results of this study suggest that coaggregation between P. gingivalis and T. forsythia is a result of cell-cell physical contact, and that coaggregation is mediated by a heat-labile component of P. gingivalis and T. forsythia component that can be activated on heat treatment.

• 정보처리학회논문지B
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• 제10B권5호
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• pp.491-496
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• 2003

본 논문에서는 정지 영상과 동영상 컨텐츠에 적용하기 위한 새로운 워터마크 설계 가이드라인을 제공한다. 본 논문에서 제안하는 워터마크 설계 방법은 인간 시각 시스템 내의 시각 세포들의 기본적인 동작 특성인 상호간섭 및 배제 작용을 이용하여, 각각의 영상 컨텐츠의 특성을 반영하여 최대한의 워터마크 강도를 구하는데 있다. 영상 컨텐츠의 최대 워터마크를 결정할 수 있다면, 자연스럽게 워터마크의 강인성이 증가되어 일반적인 영상처리 공격이나 MPEG 공격에도 강인하게 동작한 수 있다. 정지영상에서는 여러 단계의 에지 성분이 나타나게 됨에 따라 인간 시각 시스템의 민감도가 급감하게 되고, 동영상에서는 움직임이 세밀해지고 또는 많아질수록 민감도가 급감한다는 점을 모델링하기 위해, 본 논문에서는 정지 영상에서의 엔트로피 마스킹과 동영상에서의 움직임 엔트로피 마스킹을 이용하여 민감도 저하 현상을 모델링하였다. 또한, (움직임) 엔트로피 마스킹 모델을 기존의 워터마크 기법에 적용한 결과를 통해, 일반적인 워터마크 기법에 엔트로피 마스킹을 더함으로써, 워터마크의 투명성을 늘리고, 자연스럽게 워터마크의 강건성을 늘릴 수 있음을 보였다.

• 재활복지공학회논문지
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• 제4권1호
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• pp.63-70
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• 2010

시각장애인을 위한 보조공학(Assistive Technology : AT)의 연구개발은 보행과 정보 접근을 위한 것이 대부분이고, 특히 정보커뮤니케이션을 위한 음성도서용 DAISY플레이어나, 컴퓨터 화면을 읽어 주는 스크린 리더, 저시력자용 독서확대기, 점자 및 점자정보단말기 등이 상품화되어 오늘날 많은 시각장애인들에게 필수적인 보조공학기기로 자리 잡고있다. 시각장애인들이 사용하는 보조공학은 촉각이나 청각을 이용하여 시각 기능을 대행하기 때문에 감각대행기라고도 한다. 촉각을 이용한 감각대행기인 점자디스플레이와 점자정보단말기는 점자 형성을 위한 액츄에이터로 압전 소자로 만든 바이몰프가 사용되며, 점자셀의 점자(핀)는 바이몰프의 상하 운동에 의해 형성된다. 점자 셀은 휴대용 점자정보단말기에 사용되고 있기 때문에, 소형화 및 저가격화가 관건이 되며 현재는 일본의 KGS사가 세계 점자 셀(Cell) 시장의 80% 이상을 점유하고 있다. 본 연구진은 2003년에 저가/소형 원반형 점자디스플레이를 개발하여, 세계 최초로 제품화에도 성공한 바있다. 본고에서는 일본의 점자정보단말기를 비롯한 촉각디스플레이의 연구개발에 대해 검토하고 촉각을 이용한 감각대행 제품의 하나로서, 본 연구진이 개발한 원반형 점자디스플레이에 대해 고찰한다.

• Animal cells and systems
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• 제7권2호
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• pp.151-157
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• 2003

Calretinin is thought to play roles in calcium buttering. Its site of expression has been extensively studied in the central nervous system. We previously reported (Hong et at.,2002, Neurosci. Res.,44: 325-335) calretinin expression in the superficial layers of the cat superior colliculus (SC). In the present study, we studied the distribution of calretinin in the intermediate and deep layers by immunocytochemistry. We found striking differences in calretinin immunoreactivity among the superficial, intermediate, and deep layers. In contrast to the superficial layers, the intermediate and deep layers contained many calretinin-immunoreactive (IR) neurons. They formed two laminar tiers. The first tier, which was very distinctive, was found within the upper intermediate gray layers and formed clusters of labeled neurons in many sections. The second tier of calretinin-IR neurons was found in the deep gray layer. However, the second tier was not distinctive compared to the first tier and the labeled neurons did not form any clusters. Calretinin-IR neurons in the intermediate and deep layers varied dramatically in morphology and included vortical fusiform, pyriform, and stellate neurons. Neurons with varicose dendrites were also labeled. Most of the labeled neurons were small to medium in size. Enucleation appeared to have no effect on the distribution of calretinin immunoreactivity in the contralateral intermediate and deep layers of the SC. The results indicate that calretinin is present in various neurons, at different locations. These results should be applicable for better understanding of the functional organization of the SC.

• 대한두개안면성형외과학회지
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• 제14권1호
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• pp.61-64
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• 2013

Schwannomas are well-differentiated solitary benign tumors that originate from the schwann cells of the nerve sheath. They can readily occur in the head and neck regions, but the schwannoma originating from the infraorbital nerve is extremely rare and usually painless, slow-growing, and without specific symptoms. The author experienced a rare case of infraorbital schwannoma, which was completely removed through the intraoral approach. A 20-year-old woman was admitted to our hospital for a painless, solid and circular mass located on the right infraorbital region. The eyeball movement and visual field were normal. There was no globe displacement or proptosis. Preoperative computed tomography demonstrated $13{\times}10{\times}5mm$-sized soft tissue mass. On March 2011, the mass was removed through an intraoral approach. On histopathological examination, the gross specimen consisted of a smooth, well-encapsulated and light yellowish solid mass, measuring $12{\times}7{\times}5mm$. Microscopically, it presented a typical manifestation of schwannoma with Antoni A area with Verocay body, and Antoni B area on H&E stain. The result of the immunohistochemical staining was positive for the S-100 protein. The patient had hypoesthesia of the nasal septum and vestibule in the postoperative period, and this finding confirmed that the internal nasal branch of infraorbital nerve was the nerve in which the schwannoma originated. Infraorbital schwannomas are very rare and must be included in the differential diagnosis of the orbital masses inferior to the eyeball. In the case of early diagnosis, the small-sized infraorbital schwannomas can be completely removed without any scar through an intraoral approach.

• Journal of Microbiology and Biotechnology
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• 제29권5호
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• pp.827-837
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• 2019

The present study was conducted with the aim to investigate the ameliorative effects of a new soybean product (cheonggukjang) fermented with Bacillus amyloliquefaciens SCGB1 (SFBA) in atopic dermatitis (AD) mouse model. Visual evaluation of AD induction in the mice indicated the remarkable control of SFBA in reducing the pathological severity of AD-like skin lesions reported as the SCORAD score of AD clinical symptoms. The results revealed that SFBA reduced dorsal skin and epidermal thickness to a similar extent with prednisolone. Further analysis revealed the dominance of SFBA in restraining mast cell infiltration in the dermis; immunoglobulin-E expression in serum; and TH2 IL-4 cytokine and itch-related IL-31 cytokine in the mice skin and serum. SFBA also suppressed scratching behaviours in mice induced by compound 48/80. Further histological findings also revealed the alleviation of collagen fiber deposition in dermal skin of the AD mice model. These actions of SFBA were examined to be mediated by its suppression of the phosphorylation activation of key signalling molecules such as $NF-{\kappa}B$ and MAPK responsible for the induction of cytokine production. Thus, SFBA can be considered as a promising functional food for managing clinical, histological and immunological spectra associated with AD.

• 대한본초학회지
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• 제32권6호
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• pp.49-54
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• 2017

Objectives : Bangki is commonly Sinomeni Caulis et Rhizoma (SC) in Korea. But it often confused with others such as Cocculi Radix (CR), Stephaniae Tetrandrae Radix (SR) and Aristolochiae Fangchi (AR) due to the similarity in herbal names and morphological characteristics. However, because all of these types of Bangi have different healing properties, they need to be differentiated. Methods : A discrimination on external features of original plants and external characteristics of herbal medicines was carried out using visual examination, stereoscope. For the examination of Internal characteristics of herbal medicines, tissues were dyed using fast green FCF, hematoxylin and safranin O, and the features were observed by the microscope. Results : In external morphology of original plants, the original plants of SC and AR were lignum plants and others were herbaceous plants. The leaf blade and the petiole were another discriminative criteria. In external morphology of herbal medicines, SR and AR have powders and others didn't. Also, SC and CR were determined by the dense of the radiation pattern in the cross section. In internal morphology of herbal medicines, SR and AR were distinguished by the dense of Stone cells. Moreover, SC and CR were different in the pattern of medullary ray and vascular bundle. Conclusions : The results above could be used as identification keys of Bangki. Moreover, these identifications might attribute as a fundamental material to further studies like physicochemical pattern analysis and biological reaction.