• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.91-110
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• 2004

A comprehensive three-dimensional nano-particle tracking technique in micro- and nano-scale spatial resolution using the Total Internal Reflection Fluorescence Microscope (TIRFM) is discussed. Evanescent waves from the total internal reflection of a 488nm argon-ion laser are used to measure the hindered Brownian diffusion within few hundred nanometers of a glass-water interface. 200-nm fluorescence-coated polystyrene spheres are used as tracers to achieve three-dimensional tracking within the near-wall penetration depth. A novel ratiometric imaging technique coupled with a neural network model is used to tag and track the tracer particles. This technique allows for the determination of the relative depth wise locations of the particles. This analysis, to our knowledge is the first such three-dimensional ratiometric nano-particle tracking velocimetry technique to be applied for measuring Brownian diffusion close to the wall.

• 센서학회지
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• 제21권4호
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• pp.270-275
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• 2012

In this study, we have developed a mobile-based visible/NIR(Near InfraRed) imaging equipment for the animal testing. This equipment can provide visible, NIR and merged image through the viewer program. Especially, merged image help researcher to understand visual messages at animal in-vivo test. Also, it is available to send real-time images through the smart phone. Researcher can communicate with another researcher who is a long distance away. Also, the equipment was made with portable small size to enable it to commercialize.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.1-1
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• 2011

We developed a new generalized synthetic procedure, called as "heat-up process," to produce uniform-sized nanocrystals of many transition metals and oxides without a size selection process. We were able to synthesize uniform magnetite nanocrystals as much as 1 kilogram-scale from the thermolysis of Fe-oleate complex. Clever combination of different nanoscale materials will lead to the development of multifunctional nano-biomedical platforms for simultaneous targeted delivery, fast diagnosis, and efficient therapy. In this presentation, I would like to present some of our group's recent results on the designed fabrication of multifunctional nanostructured materials based on uniform-sized magnetite nanoparticles and their medical applications. Uniform ultrasmall iron oxide nanoparticles of <3 nm were synthesized by thermal decomposition of iron-oleate complex in the presence of oleyl alcohol. These ultrasmall iron oxide nanoparticles exhibited good T1 contrast effect. In in vivo T1 weighted blood pool magnetic resonance imaging (MRI), iron oxide nanoparticles showed longer circulation time than commercial gadolinium complex, enabling high resolution imaging. We used 80 nm-sized ferrimagnetic iron oxide nanocrystals for T2 MRI contrast agent for tracking transplanted pancreatic islet cells and single-cell MR imaging. We reported on the fabrication of monodisperse magnetite nanoparticles immobilized with uniform pore-sized mesoporous silica spheres for simultaneous MRI, fluorescence imaging, and drug delivery. We synthesized hollow magnetite nanocapsules and used them for both the MRI contrast agent and magnetic guided drug delivery vehicle.

• Journal of Biosystems Engineering
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• 제38권3호
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• pp.199-207
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• 2013

Purpose: Tomatoes, an important agricultural product in fresh-cut markets, are sometimes a source of foodborne illness, mainly Salmonella spp. Growth cracks on tomatoes can be a pathway for bacteria, so its detection prior to consumption is important for public health. In this study, multispectral Visible/Near-Infrared (NIR) reflectance imaging techniques were used to determine optimal wavebands for the classification of defect tomatoes. Methods: Hyperspectral reflectance images were collected from samples of naturally cracked tomatoes. To classify the resulting images, the selected wavelength bands were subjected to two-band permutations, and a supervised classification method was used. Results: The results showed that two optimal wavelengths, 713.8 nm and 718.6 nm, could be used to identify cracked spots on tomato surfaces with a correct classification rate of 91.1%. The result indicates that multispectral reflectance imaging with optimized wavebands from hyperspectral images is an effective technique for the classification of defective tomatoes. Conclusions: Although it can be susceptible to specular interference, the multispectral reflectance imaging is an appropriate method for commercial applications because it is faster and much less expensive than Near-Infrared or fluorescence imaging techniques.

• The Korean Journal of Physiology and Pharmacology
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• 제23권4호
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• pp.237-249
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• 2019

Confirming the direct link between neural circuit activity and animal behavior has been a principal aim of neuroscience. The genetically encoded calcium indicator (GECI), which binds to calcium ions and emits fluorescence visualizing intracellular calcium concentration, enables detection of in vivo neuronal firing activity. Various GECIs have been developed and can be chosen for diverse purposes. These GECI-based signals can be acquired by several tools including two-photon microscopy and microendoscopy for precise or wide imaging at cellular to synaptic levels. In addition, the images from GECI signals can be analyzed with open source codes including constrained non-negative matrix factorization for endoscopy data (CNMF_E) and miniscope 1-photon-based calcium imaging signal extraction pipeline (MIN1PIPE), and considering parameters of the imaged brain regions (e.g., diameter or shape of soma or the resolution of recorded images), the real-time activity of each cell can be acquired and linked with animal behaviors. As a result, GECI signal analysis can be a powerful tool for revealing the functions of neuronal circuits related to specific behaviors.

• Imaging Science in Dentistry
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• 제53권3호
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• pp.209-216
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• 2023

Purpose: This study was conducted to compare dental plaque scores obtained through clinical examinations and various imaging techniques, as well as to assess the effectiveness of herbal and conventional toothpastes for plaque removal. Materials and Methods: Thirty volunteers were divided into 3 groups. Each group was given a different toothpaste (from 2 herbal toothpastes and a conventional toothpaste) with which to brush their teeth for 21 days. Both initially and after brushing, dental plaque samples were collected, and plaque on the buccal surfaces of anterior teeth was scored using several imaging systems after staining with a disclosing agent. Specifically, digital dental photography, intraoral digital scanning, and FluoreCam imaging were employed to capture intraoral images. The Turesky Modified Quigley-Hein Plaque Index was used for clinical examination and image analysis. Quantitative polymerase chain reaction analyses and correlational assessments between clinical examination and imaging scores were conducted before and after toothpaste use. The Shapiro-Wilk test and Pearson correlations were utilized. Results: The lowest mean value was observed in the clinical examination without staining, while the highest was obtained using the FluoreCam method. No significant change was found in the level of any microorganism assessed following toothpaste use (P<0.05), with the exception of a decrease in S. mutans levels after using conventional toothpaste (P<0.05). Conclusion: Herbal toothpaste demonstrated plaque-removal effectiveness comparable to that of conventional toothpaste. The use of imaging methods for measuring plaque index has been suggested as a means to educate patients about plaque control and promote ongoing oral care.

• 한국토양비료학회지
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• 제45권5호
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• pp.676-682
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• 2012

본 연구에서는 생육초기 고추의 한발 스트레스 조건에서 작물 생육에 미치는 영향을 구명하기 위해 엽록소 이미지형 광분석을 이용하여 엽록소 형광 매개변수를 비교분석 하였다. 비록 통계적 유의성이 인정되지는 않았지만 전체 잎의 이미지에 나타나는 형광매개변수들의 평균값은 감소하는 경향이었다. 가변형광값에대한 최대형광값의 비는 변동이 없는 반면, 광계II의 정류상태에서의 양자수득율 및 형광감쇄율은 다소 감소하였다. 이러한 현상은 퀴논 A 단백질로부터 퀴논 B 단백질로의 전자전달의 감소를 의미하였다. 잎의 중앙부위와 엽병부근에서의 비광학적 소광 및 가변형광의 비광학적 소광 상수는 한발스트레스 4일 후 유의성있게 증가하였다. 즉 생리적 스트레스 매개변수로 활용이 가능하였다. 광계II에서의 정류상태 양자수득율의 감소는 고추잎의 모든 부위에서 공통적으로 유의성있게 측정되었다. 결론적으로 ${\Phi}PSII$ ($QY_{_-LSS}$), $NPQ_{_-LSS}$, qN 등의 엽록소형광 매개변수들은 고추의 한발스트레스를 판단할 수 있는 생리적 지표로 활용 가능한 것으로 유의성이 인정되었다.

• 한국광학회지
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• 제26권1호
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• pp.23-29
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• 2015

본 연구에서는 뇌 종양 수술에서 다수의 광원과 빔 스플리터 모듈을 사용해 종양과 혈관의 형광영상을 동시에 검출하고 획득한 형광영상을 동일한 디스플레이 장치에 표시함으로써 시술자에게 종양과 혈관의 정확한 정보를 실시간으로 제공할 수 있는 현미경 시스템을 제안한다. 5-ALA(5-Aminolevulinic acid) 와 ICG(Indocyanine green) 의 형광영상의 동시 검출을 위해 빔 스플리터(beam-splitter : BS)모듈을 사용하였고 5-ALA는 600nm, ICG는 800nm이상의 파장 대역에서 가장 효율이 뛰어나도록 구성하였다. 빔 스플리터 모듈은 파장 대역에 따라 광학기기의 구조를 변경할 수 있고 필터를 탈, 착 가능한 구조로 설계하여 필요에 따라 빔 스플리터와 필터의 종류를 변경할 수 있으며 5-ALA 및 ICG 이외의 형광염료를 사용한 시술에서 사용할 수 있다. 빔 스플리터 모듈을 통한 형광영상은 5-ALA는 가시광역, ICG는 근적외선 영역을 검출 할 수 있는 CCD 카메라를 장착해 동일한 디스플레이에서 확인할 수 있고 획득한 형광영상은 닮음 변환(similarity transform)을 이용해 원영상과 정합하여 실시간으로 시술자에게 제공하는 시스템을 구현하였다.

• 대한음성언어의학회:학술대회논문집
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• 대한음성언어학회 2016년도 제44차 춘계학술대회
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• pp.42-42
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• 2016

• Bulletin of the Korean Chemical Society
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• 제30권6호
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• pp.1245-1246
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• 2009