• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.78-87
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• 2016

Red blood cells (RBCs) are customarily adhered to a bio-functionalised substrate to make them stationary in interferometric phase-imaging modalities. This can make them susceptible to receive alterations in innate morphology due to their own weight. Optical tweezers (OTs) often driven by Gaussian profile of a laser beam is an alternative modality to overcome contact-induced perturbation but at the same time a steeply focused laser beam might cause photo-damage. In order to address both the photo-damage and substrate adherence induced perturbations, we were motivated to stabilize the RBC in OTs by utilizing a laser beam of ‘arbitrary intensity profile’ generated by a source having cavity imperfections per se. Thus the immobilized RBC was investigated for phase-imaging with sinusoidal interferograms generated by a compact and robust Michelson interferometer which was designed from a cubic beam splitter having one surface coated with reflective material and another adjacent coplanar surface aligned against a mirror. Reflected interferograms from bilayers membrane of a trapped RBC were recorded and analyzed. Our phase-imaging set-up is limited to work in reflection configuration only because of the availability of an upright microscope. Due to RBC’s membrane being poorly reflective for visible wavelengths, quantitative information in the signal is weak and therefore, the quality of experimental results is limited in comparison to results obtained in transmission mode by various holographic techniques reported elsewhere.

• The Korean Journal of Nuclear Medicine
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• v.37 no.3
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• pp.202-205
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• 2003

A 10 days old male infant with congenital megacalyces and megaureter, diagnosed by prenatal ultrasonographic screening, underwent Tc-99m DTPA renal scan for evaluation of urinary tract patency, Tc-99m DMSA scan for evaluation of renal cortical damage. He also underwent intravenous urography(IVU) and renal ultrasonography. Tc-99m DTPA renal scan demonstrates intense tracer accumulation in enlarged both renal pelvocalyses and ureters, which rapidly washout without diuretics administration. Tc-99m DMSA renal cortical scan shows no remarkable photon defect in both renal cortices and visible tracer uptake in both megaureter areas. Ultasonographic and IVU studios show enlarged both renal calyses and bullously dilated ureters, but no dilatation in renal pelvis. Follow up Tc-99m DTPA renal scan, peformed at one year later, also reveals intense tracer accumulation in enlarged both urinary tracts which rapidly washout without diuretics, and shows no significant change compare to the previous Tc-99m DTPA renal scan. Urinary tract obstruction and renal cortical damage can be easily evaluated with Tc-99m DTPA and Tc-99m DMSA scans in patiens with megacalyces and megaureter.

• Smart Structures and Systems
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• v.31 no.4
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• pp.311-323
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• 2023

Ever since ancient times, earthquakes have been a major threat to the civil infrastructures and the safety of human beings. The majority of casualties in earthquake disasters are caused by the damaged civil infrastructures but not by the earthquake itself. Therefore, the efficient and accurate post-earthquake assessment of the conditions of structural damage has been an urgent need for human society. Traditional ways for post-earthquake structural assessment rely heavily on field investigation by experienced experts, yet, it is inevitably subjective and inefficient. Structural response data are also applied to assess the damage; however, it requires mounted sensor networks in advance and it is not intuitional. As many types of damaged states of structures are visible, computer vision-based post-earthquake structural assessment has attracted great attention among the engineers and scholars. With the development of image acquisition sensors, computing resources and deep learning algorithms, deep learning-based post-earthquake structural assessment has gradually shown potential in dealing with image acquisition and processing tasks. This paper comprehensively reviews the state-of-the-art studies of deep learning-based post-earthquake structural assessment in recent years. The conventional way of image processing and machine learning-based structural assessment are presented briefly. The workflow of the methodology for computer vision and deep learning-based post-earthquake structural assessment was introduced. Then, applications of assessment for multiple civil infrastructures are presented in detail. Finally, the challenges of current studies are summarized for reference in future works to improve the efficiency, robustness and accuracy in this field.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.259-266
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• 2023

Global climate change is increasing, and the damage and scale of localized torrential rains are increasing. Pre-flood analysis simulation results should be derived from rainfall data through rainfall forecasts to prevent flood damage. In addition, it is necessary to control the use and management of flood response disaster prevention facilities through immediate decision-making. However, methods using spills and flood models such as XPSWMM and GATE2018 are limited due to professional usability and complex analytical procedures. Prototype (flood disaster prevention facility simulator) of this study is developed by calculating rainfall (short-term and long-term) using CBD software development methods. It is also expected to construct administrator and user-centric interfaces and provide GIS and visible data (graphs, charts, etc.).

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.1-9
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• 1999

Numerous observations revealed strong evidence of increased middle ultraviolet radiation or UV-B (280 ~ 320 nm) at the earth's surface resulting from stratospheric ozone depletion. UV is the waveband of electromagnetic radiation which is strongly absorbed by nucleic acids and proteins, thus causing damage to living systems. It has been recorded in the East Sea, Korea that solar UV-B impinging on the ocean surface penetrates seawater to significant depths. Recent researches showed that exposure to UV-B for as short as 2h at the ambient level (2.0 Wm$^{-2}$) decreased macroalgal growth and photosynthesis and destroyed photosynthetic pigments. These may suggest that UV-B could be an important environmental factor to determine algal survival and distribution. Some adaptive mechanisms to protect macroalgae from UV-damage have been found, which include photoreactivation and formation of UV-absorbing pigments. Post-illumination of visible light mitigated UV-induced damage in laminarian young sporophytes with blue the most effective waveband. The existence of UV-B absorbing pigments has been recognized in the green alga, Ulva pertusa and the red alga, Pachymeniopsis sp., which is likely to exert protective function for photosynthetic pigments inside the thalli from UV-damage. Further studies are however needed to confirm that these mechanisms are of general occurrence in seaweeds. Macroalgae together with phytoplankton are the primary producers to incorporate about 100 Gt of carbons per year, and provide half of the total biomass on the earth. UV-driven reduction in macroalgal biomass, if any, would therefore cause deleterious effects on marine ecosystem. The ultimate impacts of increasing UV-B flux due to ozone destruction are still unknown, but the impression from UV studies made so far seems to highlight the importance of setting up long-term monitoring system for us to be able to predict and detect the onset of large -scale deterioration in aquatic ecosystem.

• Journal of Plant Biotechnology
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• v.34 no.4
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• pp.299-305
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• 2007

Oxidative stress is a major damaging factor for plants exposed to environmental stresses. Previously, we have generated transgenic potato (cv. Superior) plants expressing both CuZnSOD and APX genes in chloroplast under the control of an oxidative stress-inducible SWPA2 promoter (referred to as SSA plants) and selected the transgenic potato plant lines with tolerance against methyl viologen (MV)-mediated oxidative stress. When leaf discs of SSA plants were subjected to $3{\mu}M$ methyl viologen (MV), they showed approximately 40% less damage than non-transgenic (NT) plants. SSA plantlets were treated with $0.3{\mu}M$ MV stress, SSA plants also exhibited reduced damage in root growth. When 350 MV was sprayed onto the whole plants, SSA plants showed a significant reduction in visible damage, which was approximately 75% less damage than leaves of NT plants. These plants will be used for further analysis of tolerance to environmental stresses, such as high temperature and salt stress. These results suggest that transgenic potato (cv. Superior) plants would be a useful plant crop for commercial cultivation under unfavorable growth conditions.

• Korean Journal of Remote Sensing
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• v.38 no.5_2
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• pp.669-683
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• 2022

The frequency and damage of forest fires have tended to increase over the past 20 years. In order to effectively respond to forest fires, information on forest fire damage should be well managed. However, information on the extent of forest fire damage is not well managed. This study attempted to present a method that extracting information on the area of forest fire in real time and quasi-real-time using visible infrared imaging radiometer suite (VIIRS) images. VIIRS data observing the Korean Peninsula were obtained and visualized at the time of the East Coast forest fire in March 2022. VIIRS images were classified without supervision using iterative self-organizing data analysis (ISODATA) algorithm. The results were reclassified using the relationship between the burned area and the location of the flame to extract the extent of forest fire. The final results were compared with verification and comparison data. As a result of the comparison, in the case of large forest fires, it was found that classifying and extracting VIIRS images was more accurate than estimating them through forest fire occurrence data. This method can be used to create spatial data for forest fire management. Furthermore, if this research method is automated, it is expected that daily forest fire damage monitoring based on VIIRS will be possible.

• Journal of Photoscience
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• v.9 no.2
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• pp.382-384
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• 2002

When illuminated with strong visible light, the reaction center Dl protein of photo system II is photodamage and degraded. Reactive oxygen species and endogenous cationic radicals generated by photochemical reactions are the cause of the damage to the Dl protein. Recently we found that the photodamaged Dl protein cross-links with the surrounding polypeptides such as D2 and CP43 in photosystem II. As the cross-linking reaction is dependent on the presence of oxygen, reactive oxygen species are suggested to be involved. Among the reactive oxygen species examined, ？ OH was most effective in the formation of the cross-linked products. These results indicate that the cross-linking is mostly due to ？ OH generated at photosystem II. The cross-linking site of the Dl protein is not known. As several tyrosine residues exist at the D­E loop of the Dl protein, there is a possibility that di-Tyr is formed between the D­E loop of the Dl protein and surrounding polypeptides during the strong illumination. Therefore, we examined the formation of di-Tyr using the monoclonal antibody against di-Tyr under excess illumination of the photosystem II membranes. The results obtained here suggest that no di-Tyr is formed during the excess illumination of photosystem II.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.6 no.1
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• pp.1-15
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• 2008

This study was designed to investigate the effect of treadmill exercise of low-intensity and high-intensity on the functional recovery and histological change in spinal cord injury rats. Sprague-Dawley rats were experimented(n=15) for this research. Spinal cord injury was induced by the NYU drop impacter device after laminectomy. After operation, rats were test at modified Tarlov scale at 3 days, and divided into the control group(n=5), experimental group I(n=5, low-intensity treadmill) and experimental group II(n=5, high-intensity treadmill). The rats were disciplined from 7 day through 21 day. Functional recovery was evaluated by the BBB scales and the Grid Walk test for the progressive locomotor recovery at 3, 7, 14, 21 days. Histopathological studies for the muscle in order to observation the change of damage and size of the organized surface which is visible visually it executed hematoxylin & eosin stain. According to the result of 4 weeks of treadmill exercise, group II showed improvement than group I of motor behavior after spinal cord injury.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.139-147
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• 1997

Argon laser used in this case report, is special in having two wavelength of 488, 514nm blue-green visible light spectrum. Blue light is used for composite resin polymerization and caries detection. Green light is used for soft tissue surgery and coagulation. Maximum absorption of this laser light occurs in red pigmentation such as hemoglobin. The argon laser may be well-suited for selective destruction of blood clots and hemangioma with minimal damage to adjacent tissues. Argon laser light penetrates tissue to the 1 mm depth, so its thermal intensity is lower than $CO_2$ laser light. Also, due to its short wavelength it can be focused in a small spot and even single gene can be excised by this laser and microscopy. After applicating argon laser to 4 patient for surgical procedure and to 1 patient for curing the composite resin, following results were obtained. 1. Improved visibility were gained due to hemostasis and no specific technique were needed according to easy recontouring of the tissue. 2. Ability to use by contact mode, tactile sense was superior but tissue dragability and accumulation of tissue on the tip needed sweeping motion. 3. Additive local anesthetic procedure was needed. 4. No suture and less curing time reduced chair time, this made argon laser available in pediatric dentistry.