• Biomolecules & Therapeutics
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• 제26권1호
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• pp.81-92
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• 2018

It is widely accepted that altered metabolism contributes to cancer growth and has been described as a hallmark of cancer. Our view and understanding of cancer metabolism has expanded at a rapid pace, however, there remains a need to study metabolic dependencies of human cancer in vivo. Recent studies have sought to utilize multi-modality imaging (MMI) techniques in order to build a more detailed and comprehensive understanding of cancer metabolism. MMI combines several in vivo techniques that can provide complementary information related to cancer metabolism. We describe several non-invasive imaging techniques that provide both anatomical and functional information related to tumor metabolism. These imaging modalities include: positron emission tomography (PET), computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS) that uses hyperpolarized probes and optical imaging utilizing bioluminescence and quantification of light emitted. We describe how these imaging modalities can be combined with mass spectrometry and quantitative immunochemistry to obtain more complete picture of cancer metabolism. In vivo studies of tumor metabolism are emerging in the field and represent an important component to our understanding of how metabolism shapes and defines cancer initiation, progression and response to treatment. In this review we describe in vivo based studies of cancer metabolism that have taken advantage of MMI in both pre-clinical and clinical studies. MMI promises to advance our understanding of cancer metabolism in both basic research and clinical settings with the ultimate goal of improving detection, diagnosis and treatment of cancer patients.

• Current Optics and Photonics
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• 제7권4호
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• pp.398-407
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• 2023

We explored a method to evaluate imaging performance for the optimal assembly of an endoscopic miniature lens and a sensor constituting an imaging module at the distal end of gastrointestinal endoscopy. For the assembly of the imaging module, the image sensor was precisely located at the focal plane when collimated light passed through the endoscopic lens. As another method, the distance between the lens and sensor was adjusted to obtain the highest focus index from images measured the star chart of the International Organization for Standardization (ISO) standard at various positions. We analyzed the slanted-edge modulation transfer function (MTF), corresponding depth of field, and number of line pairs for MTF 50% and 20% at each working distance within the range of 5-100 mm for imaging modules assembled in different ways. Assembly conditions of the imaging module with better MTF performance were defined for each working distance range of 5-30 mm and 30-100 mm, respectively. In addition to the MTF performance, the focus index of each assembled module was also compared. In summary, we examined the performance of imaging modules assembled with different methods within the suggested working distance and tried to establish the optimal assembly protocol.

• 전자통신동향분석
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• 제36권3호
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• pp.97-105
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• 2021

The terahertz wave (THz wave) is a band between infrared and microwaves and is defined as an electromagnetic wave having a frequency of 0.1 to 10 THz band. THz waves have the property of transmitting nonpolar materials, which the visible light cannot be transmitted, such as ceramics, plastics, and paper; and the photon energy is low, such as several meV. For this reason, non-destructive testing equipment based on THz imaging technology can be applied to the industrial field. Recently, THz imaging technology was applied in wide industrial fields, such as automobiles, batteries, food, medical, and security, and being actively studied. In this paper, we describe the research trends of terahertz imaging technology and experimental results. Furthermore, we summarize the recent commercialized terahertz camera. Finally, we present the research results in the field of the human security scanner system.

• 한국가시화정보학회지
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• 제21권3호
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• pp.65-74
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• 2023

Compared to epifluorescence(EPI) microscopy which captures fluorescence from the entire depth of sample, total internal reflection fluorescence(TIRF) can selectively visualize only a single surface of it. TIRF uses a thin evanescent field generated by the total internal reflection of laser light on surface. However, conventional TIRF system are designed for total internal reflection to occur at the upper surface of sample, making them unsuitable for sessile droplet imaging. We designed a TIRF system suitable for a sessile droplet imaging by utilizing slide glass as a lightguide. We presented the details for constructing the TIRF system using a prism, slide glass, air slit, and optical trap. Then, we compared the TIRF with EPI by imaging the droplet with fluorescent particles during its drying process. As a result, TIRF allows us to distinctly visualize the drying pattern on the bottom surface of droplet.

• Current Optics and Photonics
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• 제7권6호
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• pp.745-754
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• 2023

In order to test the recognition ability and accuracy of a target imaging simulator under the irradiation of solar stray light in a laboratory environment, it needs to be fixed on a five-axis turntable during a hardware-in-the-loop simulation test, so the optical system of the simulator should have a long exit pupil distance. This article adopts a secondary imaging method to design a projection optical system suitable for thin-film-transistor liquid crystal displays. The exit pupil distance of the entire optical system is 1,000 mm, and the final optimization results in the 400 nm-850 nm band show that the modulation transfer function (MTF) of the optical system is greater than 0.8 at the cutoff frequency of 72 lp/mm, and the distortion of each field of view of the system is less than 0.04%. Combined with the design results of the optical system, TracePro software was used to model the optical system, and the simulation of the target imaging simulator at the magnitude of -1 to +6 Mv was analyzed and verified. The magnitude error is less than 0.2 Mv, and the irradiance uniformity of the exit pupil surface is greater than 90%, which meets the requirements of the target imaging simulator.

• Investigative Magnetic Resonance Imaging
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• 제1권1호
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• pp.114-118
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• 1997

목적: 기능적 MR 영상은 외부자극에 따라, 이에 상응하는 특정한 뇌피질 부위의 혈류량의 변화를 신호강도의 차이로 나타내는 방법이다. 시각피질에 대한 기능적 MR은 환자가 광자극을 응시함으로써 수행될 수 있는 것으로, 이의 수행에는 적절한 형태의 광자극원이 필수적이다. 이에 저자는 광자극원의 크기가 시각피질 활성화에 영향을 미칠 수 있는지 알아보기 위하여 본 연구를 하였다. 대상 및 방법: 정상적인 시력을 가진 자원자 5명을 대상으로 시각활성화 기능적 MR을 시행하였다. 광자극원은 $11{\times}8cm$ 크기의 기판에 적색 LED(light-emitting diodes) 39개를 박고 직류전원을 사용하도록 만들었다. 이를 크기에 따라 full field, half field 및 focal central field의 3가지로 구분하고 8Hz로 점멸하였다. EPI 기법으로 6회의 광자극 기간과 6회의 휴식기간을 번갈아 3차례 시행하여 총 36회의 검사를 하고, Z-score로 통계처리하였다. 이 때 얻은 활성화 영상을 같은 부위의 T1강조영상에 결합시켰다. 각 경우에서 시각피질에서 활성화된 pixel의 수를 full field, half field 및 focal central field에서 얻어진 pixel 수의 합으로 나누어 활성화지수를 구하였다. 이 활성화지수를 토대로 광원크기와의 관계를 분석하였다. 결과: Full field로 자극을 주었을 때 시각피질의 평균 신호강도의 증가는 약 9.6%였다. 4명에서 활성화지수는 full field, half field, focal central field의 순으로 감소하였으며, 나머지 1명에서는 half field 시의 값이 full field 시의 값보다 컸다. 광원크기에 따른 활성화지수의 범위는 full field 43-73%(평균 55%), half field 22-40%(평균 32%), focal central field 5-24%(평균 13%)였다. 결론: 기능적 MR영상을 이용하여 시각피질의 활성화를 용이하게 확인할 수 있었으며 광자극원의 크기에 따라 증가되는 시각피질 활성화를 입증할 수 있었다.

• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.272-278
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• 2009

Recently, there has been a growing interest in optical imaging of neural activity because the optical neuroimaging has considerable advantages over conventional imaging. Birefringence of the axon has been reported to change during neural activation, but the neurophysiological origin of the change is still unresolved. This study hypothesizes that the birefringence signal is at least partially attributed to the transient cellular volume change associated with nerve excitation. To examine this hypothesis, we investigated how the intensity of cross-polarized light transmitting through the axon would change as the size of the axon changes. For this purpose, a two-dimensional finite-difference time-domain program was developed with the improvement of the total-field/scattered-field method which reduces numerical noise. The results support our hypothesis in that the computed cross-polarized signals exhibit some agreement with previously-reported birefringence signals.

• Journal of information and communication convergence engineering
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• 제18권3호
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• pp.188-193
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• 2020

In this paper, we examine whether the 3D image experience through a light-field display device showed the difference in the arousal of the user compared with the 2D image experience. For our experiment, the Looking Glass^TM (LG) was used as a lightfield display device that provided 3D images, and 2D images were provided by digital and printed images. The subject's facial behavior during each media experience was recorded for analysis and the degree of arousal was measured by FaceReader^TM. As a result, the first image presented in the first order among the three kinds of images showed that there was a statistical difference in the degree of arousal between the three media. However, no significant differences were found between the three media in the other images. This may be because the arousal did not increase from the experience of the second image through the LG, owing to habituation. In conclusion, the 3D imaging experience may appear in the beginning, but does not continue.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1528-1532
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• 2000

The conventional optics and near field optics are compared numerically in the view points of the spot size and propagation characteristics. The decaying characteristics of near field light require the optics to access the object within several tens of nanometers. Therefore the gap control is one of the main issues in the near field optics area. In this paper the gap control is done by using the shear force of the NF(Near Field) probe and the characteristics are examined. The probe is modeled as a 2'nd order mass-spring-damper system driven by a harmonic force. The primary cause of the decrease in vibration amplitude is due to the damping force - shear force - between the surface and the probe. Using the model, damping constant and resonance frequency of the probe is calculated as a function of probe-sample distance. Detecting the amplitude and phase shift of the NF probe attached to the high Q-factor piezoelectric tuning fork, we can control the position of the NF probe about 0 to 50nm above the sample. The feedback signal to regulate the probe-sample distance can be used independently for surface topography imaging. 3-D view of the shear force image of a testing sample with the period of $1{\mu}m$ will be shown.

• Current Optics and Photonics
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• 제8권1호
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• pp.97-104
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• 2024

In aerial cameras, image quality is easily affected by weather, temperature, and the attitude of the aircraft. Aiming at this phenomenon, based on the theory of two-step zoom optical systems, a dual-band optical-despun two-step zoom optical system is designed. The system has a small field of view of 2.00° × 1.60°, and a large field of view of 4.00° × 3.20°. In the zoom process, the wavelength range is 0.45-0.70 ㎛ and 0.75-1.10 ㎛, and the size of the optical system is 168 mm (L) × 90 mm (W) × 60 mm (H). The overall lens weight is only 170.8 g, which has advantages for miniaturization and light weight. At the Nyquist frequency of 104 lp/mm, the modulation transfer function of the visible-light optical system is more than 0.44, and that of the near-infrared optical system is more than 0.30, both of which have good imaging quality and tolerance characteristics in the range of -45 to 60 ℃.