• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.308-313
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• 2014

Recently, for longevity of resident building, the main trend is that the change of the inside space organization of resident building from wall construction to rhamen construction, which resulted in increase in use of lightweight composite panel. Thus, in this study, authors analyzed the engineering property of oxide of magnesium depending on the magnesium chloride addition ratio. The results of this research is expected to contribute on providing a fundamental material for the surface materials of lightweight composite panel. As the result of the experiment, as fluidity increased, air content decreased and initial set and final set as the magnesium chloride addition ratio increase. In the aspect of flexural strength and compressive strength, the test specimen showed the highest strength at 40% of the magnesium chloride addition ratio. At 20% of the magnesium chloride addition ratio, the test specimen showed the lowest water absorption rate. As the magnesium chloride addition ratio increases, the expansibility tends to increase as well in the aspect of shrinkage strain. After observing microstructure, we can see hydration products in the form of needle. It appeared high flexural strength because the hydration products have mineral fibrous tissue shape, which also contribute to the cause of the expansibility.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.10-18
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• 2014

The objective of this study was to investigate the correlation between cattle breeds and deposit of adipose tissues in different positions and the gene expressions of peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$), fatty acid synthase (FASN), and Acyl-CoA dehydrogenase (ACADM), which are associated with lipid metabolism and are valuable for understanding the physiology in fat depot and meat quality. Yanbian yellow cattle and Yan yellow cattle reared under the same conditions display different fat proportions in the carcass. To understand this difference, the expression of $PPAR{\gamma}$, FASN, and ACADM in different adipose tissues and longissimus dorsi muscle (LD) in these two breeds were analyzed using the Real-time quantitative polymerase chain reaction method (qRT-PCR). The result showed that $PPAR{\gamma}$ gene expression was significantly higher in adipose tissue than in LD in both breeds. $PPAR{\gamma}$ expression was also higher in abdominal fat, in perirenal fat than in the subcutaneous fat (p<0.05) in Yanbian yellow cattle, and was significantly higher in subcutaneous fat in Yan yellow cattle than that in Yanbian yellow cattle. On the other hand, FASN mRNA expression levels in subcutaneous fat and abdominal fat in Yan yellow cattle were significantly higher than that in Yanbian yellow cattle. Interestingly, ACADM gene shows greater fold changes in LD than in adipose tissues in Yan yellow cattle. Furthermore, the expressions of these three genes in lung, colon, kidney, liver and heart of Yanbian yellow cattle and Yan yellow cattle were also investigated. The results showed that the highest expression levels of $PPAR{\gamma}$ and FASN genes were detected in the lung in both breeds. The expression of ACADM gene in kidney and liver were higher than that in other organs in Yanbian yellow cattle, the comparison was not statistically significant in Yan yellow cattle.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.1
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• pp.29-34
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• 2016

In this study, development of multichannel filter module and characteristic evaluation for bio imaging were studied. The filter module was fabricated in order to realize near infrared fluorescence imaging of 700 nm and 800 nm wavelength ranges, and contrast imaging analysis for characteristic evaluation of the filter module was studied through signal to back ground ratio (SBR), controlled by parameters such as magnification, exposure, gain. Furthermore, phantoms, which are biomimetic tissue with equal optical properties of kidney and liver, were fabricated to study characteristics of both filter module depending on thickness and exposure amount of light source for bio imaging analysis. The fabricated filter module has more than 4 of SBR difference despite changes of magnification, exposure, gain, and in the case of the kidney phantom and the liver phantom, contrast imaging of more than 4 of SBR was confirmed on 50 mA, 60 mA exposure amount of light source respectively.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.638-646
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• 2014

Background The combination of polycaprolactone and hyaluronic acid creates an ideal environment for wound healing. Hyaluronic acid maintains a moist wound environment and accelerates the in-growth of granulation tissue. Polycaprolactone has excellent mechanical strength, limits inflammation and is biocompatible. This study evaluates the safety and efficacy of bio-conjugated polycaprolactone membranes (BPM) as a wound dressing. Methods 16 New Zealand white rabbits were sedated and local anaesthesia was administered. Two $3.0{\times}3.0cm$ full-thickness wounds were created on the dorsum of each rabbit, between the lowest rib and the pelvic bone. The wounds were dressed with either BPM (n=12) or Mepitel (n=12) (control), a polyamide-silicon wound dressing. These were evaluated macroscopically on the 7th, 14th, 21st, and 28th postoperative days for granulation, re-epithelialization, infection, and wound size, and histologically for epidermal and dermal regeneration. Results Both groups showed a comparable extent of granulation and re-epithelialization. No signs of infection were observed. There was no significant difference (P>0.05) in wound size between the two groups. BPM (n=6): $8.33cm^2$, $4.90cm^2$, $3.12cm^2$, $1.84cm^2$; Mepitel (n=6): $10.29cm^2$, $5.53cm^2$, $3.63cm^2$, $2.02cm^2$; at the 7th, 14th, 21st, and 28th postoperative days. The extents of epidermal and dermal regeneration were comparable between the two groups. Conclusions BPM is comparable to Mepitel as a safe and efficacious wound dressing.

• Progress in Medical Physics
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• v.11 no.1
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• pp.39-47
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• 2000

In Stereotactic Radiosurgery (SRS), there are three imaging methods of target localization, such as digital subtraction Angiography (DSA), computed tomography (CT), magnetic resonance imaging (MRI). Especially, DSA and MR images have a distortion effect generated by each modality. In this research, image properties of DSA were studied. A first essential condition in SRS is an accurate information of target locations, since high dose used to treat a patient may give a complication on critical organ and normal tissue. Hut previous localization program did not consider distortion effect which was caused by image intensifier (II) of DSA. A neurosurgeon could not have an accurate information of target locations to operate a patient. In this research, through distortion correction, we tried to calculate accurate target locations. We made a grid phantom to correct distortion, and a target phantom to evaluate localization algorithm. The grid phantom was set on the front of II, and DSA images were obtained. Distortion correction methods consist of two parts: 1. Bilinear transform for geometrical correction and bilinear interpolation for gray level correction. 2. Automatic detection method for calculating locations of grid crosses, fiducial markers, and target balls. Distortion was corrected by applying bilinear transform and bilinear interpolation to anterior-posterior and left-right image, and locations of target and fiducial markers were calculated by the program developed in this study. Localization errors were estimated by comparing target locations calculated in DSA images with absolute locations of target phantom. In the result, the error in average with and without distortion correction is $\pm$0.34 mm and $\pm$0.41 mm respectively. In conclusion, it could be verified that our localization algorithm has an improved accuracy and acceptability to patient treatment.

• Journal of Biomedical Engineering Research
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• v.38 no.2
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• pp.62-73
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• 2017

To identify a solution for the restricted availability of healthy lungs and the high risk of immune rejections following organ transplantation, tissue engineering techniques for culturing lungs have been studied by many research groups. The most promising method for culturing lungs is the utilization of a bio-scaffold that was prepared using harvested organs from human donors or other animals by removing their original cells. In this study, a pulsatile perfusion pump was used to alleviate the cell removal effect with the high fluid-dynamic power of the perfusion stream during the decellularization process, while other conventional studies focused on chemical methods to identify efficient detergents. The purpose of this study was to analyze the developed device by using energy equivalent pressure (EEP), which is an indicator of pulsatility, to understand the characteristics of pulsatile energy transmitted according to the load size by using the artificial model and compare it with the measured EEP. The pulsatility of the device can be estimated with the concept of fluid-dynamic energy during a particular constant time period or fluid-dynamic power represented as EEP and EEP increment. Because the measured EEP of perfusion flow during decellularization can be changed by the amount of fluid leakage and the degree of clogging in the capillary vessels, EEP should be measured to determine whether the decellularization is progressing without problems. The decrement of EEP caused by the high perfusion resistance was observed from some experimental results that were obtained with artificial models. EEP can be used to monitor the decellularization process after analyzing the varying EEP according to the amount of load. It was confirmed that the EEP was maintained at a high level in the experiment using the harvested lungs from 12-13-week-old rats. In addition, it was confirmed that the cell removal time was faster than when continuous perfusion was performed. In this study, pulsatile power delivered to the lungs was measured to monitor the process of cell removal, and it serve as the evidence for efficient decellularization.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.1
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• pp.45-55
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• 2016

Light shows various optical behaviors such as reflection, absorption, and scattering on skin for individuals. In particular, reflection of light from the skin has been widely used as the brightness index of the skin of individuals through the measurement of the physical quantity of spectral reflectance. Therefore, the study of light behavior on skin would be useful for the preparation of new evaluation method in the development stage of make-up products. In this study, multi-dimensional analysis for spectral reflectance behavior of light on individual skin was performed using Kubelka-Munk model. Also, we analyzed the contribution of skin parameters such as skin thickness and hemoglobin, which could affect the spectral reflectance, using above model and literature information. Base on this, we calculated the theoretical reflectance of normal women for visual light, which showed good agreement with the measured reflectance. Our study of light propagation in skin based on Kubelka-Munk model provides useful insight for the development of personalized cosmetic in the near future.

• Korean Journal of Optics and Photonics
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• v.18 no.5
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• pp.367-372
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• 2007

Cervical dysplasia induces morphologic changes in the cervical epithelium which involve changes in the nuclear/cytoplasmic (N/C) ratio. Since the nucleus is one of the significant scattering sources, the N/C ratio change reflects the degree of circular polarization (DOCP) with the depth of signals. Therefore, we used the polarization-sensitive OCT (PS-OCT) technique to measure the polarization changes caused by scattering. Cervical tissues were obtained from a high-grade squamous intraepithelial lesion (H-SIL) of one woman and from low normal women. We obtained the mean of the DOCP as a function of depth in the cervix and quantified the change ratio of the DOCP using slopes that were determined by linear fits in the epithelium layer. We found that DOCP of H-SIL decayed faster than that of normal tissue because of the higher scattering in H-SIL as expected. This result indicates that the PS-OCT system might be useful in measurements of change ratio of DOCP with depth for screening of cervical dysplasia.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.138-146
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• 2018

Photodynamic therapy (PDT) is a great potential approach for the localized tumor removal with fewer metastatic potentials and side effects in treating the disease. In the treatment process, a photosensitizer (PS) that absorbs a light energy to generate reactive oxygen is essential. In general, a visible light is used as a light source of PDT, so that side effects from the light source are inevitable. For this reason, upconversion nanoparticles (UCNPs) using near-infrared (NIR) as an excitation source are attracting attention in the field of disease diagnosis and treatment. UCNPs have the low cytotoxicity and phototoxicity, and also advantages such as deep tissue penetration and low background autofluorescence. For PDT, UCNPs should be combined with a PS which absorbs the light energy from UCNPs and transfers it to the surrounding oxygen to produce reactive oxygen. In addition, the therapeutic efficacy can be improved by modifying nanoparticle surfaces, adding anti-cancer drugs, or combining with photothermal therapy (PTT). In this review, we summarize the recent research to improve the efficiency of PDT using UCNPs.

• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.173-182
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• 1999

Contrast-enhanced CT has an important role in assessing liver lesions, the optimal protocol to get most effective result is not clear. The mein goal when deciding injention protocol is to optimize lesion detectability with rapid scanning when lesion to liver contrast is maximum. For this purpose, we developed a physiological model of the contrast medium enhancement based on the compartment modeling and pharmacokinetics. Blood supply to liver is achieved in two paths. This dual supply characteristic distinguishes the CT enhancement of liver from that of the other organs. The first path is by hepatic artery and to second, by portal vein. However, it is assumed that only gepatic artery can supply blood to hepatocellular carcinoma(HCC) compartment, thus, the difference of contrast enhancement is resulted between normal liver tissue and hepatic tumor. By solving differential equations for each compartment simultaneously using the computer program Matlab, CT contrast-enhancement curves were simulated. The simulated enhancement curves for aortic, hepatic, portal vein, and HCC compartments were compared with the mean enhancement curves from 24 patients exposed to the same protocols as the simulation. These enhancement curves showed a good agreement. Furthermore, we simulated lesion-to-liver curves for various injection protocols, and the effects were analyzed. The variables to be considered in the injection protocol were injection rate, dose, and concentration of contrast material. These data may help to optimize scanning protocols for better diagnosis.