• Proceedings of the KSME Conference
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• 2002.08a
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• pp.811-814
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• 2002

Using a mathematical theory, we show that the optimality condition of a turbulent diffuser with maximum pressure recovery at the exit is zero shear stress along the wall. The optimal diffuser shape is designed through iterative procedures by using the $k-{\varepsilon}-{\nu}^{2}-f$ turbulence model for flow simulation. The Reynolds number based on the bulk mean velocity and the channel height at the diffuser entrance is 18,000. We also perform large eddy simulation to validate the shape design results and investigate the flow characteristics near the zero-skin friction wall. Results from large eddy simulation show that the skin friction is slightly higher than zero but is still very small as compared to that of the flat plate boundary layer flow Although the time-averaged wall shear stress is slightly above zero along the diffuser wall, instantaneous flow reversals occur intermittently. The streamwise mein velocity shows an asymptotic behavior of the half-power-law near the wall where the skin friction is close to zero.

• Journal of Marine Bioscience and Biotechnology
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• v.4 no.1
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• pp.31-34
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• 2010

The primary function of the skin is to protect the body from the unwanted environmental influences. The outermost layer of the skin is stratum corneum which consists of corneocytes surrounded by lipid regions. Ceramides covalently bound to keratinocytes are essential for the barrier function of the skin, which can be disturbed in the disease, like xerosis. Xerosis is an abnormal dryness of the skin which reduced the thickness of stratum corneum and ceramide content decreasing with age. In this study, 36 seaweed extracts have been tested for screening of xerosis inhibitory agent by in vitro HaCaT keratinocyte assay. Ishige sinicola and Helminthocladia australis induced the significant amount of ceramide-like substance I in HaCaT keratinocyte among the tested seaweed extracts. Sargassum fulvellum, Chondrus ecellatus and Gigartina tenella also induced the ceramide-like substance I whereas Helminthocladia australis and Pachymeniopsis elliptica induced the ceramide-like II from HaCaT keratinocyte.

• Korean Journal of Veterinary Research
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• v.19 no.2
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• pp.153-157
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• 1979

The authors encountered 78 cases of pig from two swine herds with severe dermatitis, which had been fed with commercial rations. Main clinical signs were hard crust formation or erythema and papules on the skin and retarted growth. The skin lesions were visible on the limb joints in all cases. In some cases, however, crusts occurred on the tail, perineum, hip, ear, back, or neck. In one case the entire body surface was covered with thick crust. No mites were detected on the microscopic examination of skin scrapings. Histological examination of biopsies skin specimens taken from the lesions revealed typical parakeratotic changes: the cornified layer of epidermis was irregularly inreased in thickness and contained numerous nuclei. The provision of dietary supplementation with zinc sulfate and soybean oil for 10 days showed marked curative effect.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.14 no.2
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• pp.35-38
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• 2001

Dermatitis herpetiformis (DH) is a chronic disease of the skin marked by groups of watery, itch blisters. It is characterized by urticarial plaques and blisters on the elbows, buttocks, and knees, although other sites may also be involved. The ingestion of gluten (the proteins gliadin and prolamin contained in wheat, rye, oats, and barley) triggers an immune system reponse that deposits a substance, IgA (immonuglobin A), under the top layer of skin. IgA is present in affected as well as unaffected skin. DH is a hereditary autoimmune disease linked with celiac disease. Treatment for DH is twofold. (1) Remove the cause: gluten. (2) Suppress the skin response with drugs such as Dapsone or some other sulphones. The latter is the most common treatment used as it is rapidly relieves the itch. However there are some side effects associated with these medications and they need to be taken under medical monitoring with blood tests to detect side effects. Recently, we experienced a DH and that was successfully treated by the herbal medication and external therapy. The medications taken by the patient were yongdamsagantanggami and external therapy were gosam and gumunhwa. So we report this case with a bief review of the oriental medical and medical literatures.

• Journal of the Korean Institute of Rural Architecture
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• v.23 no.3
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• pp.1-8
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• 2021

Rural multi-purpose buildings needs to ensure their safety against various disasters. Therefore, a pile foundation, which is a foundation type that can transmit the load of the structure to the bedrock layer, has been designed. The pile foundation method is largely divided into driving piles method and pre-bored pile method. Recently, in order to respond to the Noise and Vibration Control Act and related environmental complaints, construction of pile foundation adopts pre-bored pile method. The bearing capacity of the pre-bored pile method is calculated through a load test in situ. However, a disadvantage stems in that it is difficult to measure the ultimate bearing capacity due to field conditions. Therefore, in this study, the skin frictional force of pre-bored pile was measured through a model test in laboratory for each pile filling material. In result, the pile filling material with using circulating resources shows superior skin frictional force than ordinary portland cement. This study also judged that the result can be applied in place of ordinary Portland cement in the field.

• Geomechanics and Engineering
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• v.27 no.6
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• pp.595-604
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• 2021

With the advantages of high permeability and strength, pervious concrete piles can be suitable for ground improvement with high water content and low bearing capacity. By comparing the strength and permeability of pervious concrete with different aggregate sizes (3-5 mm and 4-6 mm) and porosities (20%, 25%, 30% and 35%), the recommended aggregate size (3-5 mm) and porosity (30%) can be achieved. The model tests of the pervious concrete piles in soft soil (silt and clay) foundations were conducted to evaluate the bearing characteristics, results show that, for the higher consolidation efficiency of the silty foundation, the bearing capacity of the silty foundation is 16% higher, and the pile-soil stress ratio is smaller. But when it is the ultimate load for the piles, they will penetrate into the underlying layer, which reduces the pile-soil stress ratios. With higher skin friction of the pile in the silty foundation, the pile penetration is smaller, so the decrease of the pile axial force can be less. For the difference in consolidation efficiency, the skin friction of pile in silt is more affected by the effective stress of soil, while the skin friction of pile in clay is more affected by the lateral stress. When the load reaches 4400 N, the skin friction of the pile in the silty foundation is about 35% higher than that of the clay foundation.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.206.2-206.2
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• 2005

• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.31.2-31.2
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• 2008

• Science of Emotion and Sensibility
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• v.26 no.4
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• pp.41-50
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• 2023

This study aims to develop electromyography (EMG) textile electrodes and assess their performance and signal stability by examining variations in layer count and fabric types. We fabricated the electrodes through layering and pressing techniques, focusing on configurations with different layer counts (Layer-0, Layer-1, and Layer-2). Our findings indicate that layer presence significantly influences muscle activation measurements, with enhanced performance correlated with increased layer numbers. Subsequently, we created electrodes from five distinct fabrics (neoprene, spandex cushion, 100% polyester, nylon spandex, and cotton canvas), each maintaining a Layer-2 structure. In performance tests, nylon spandex fabric, particularly heavier variants, outperformed others, while the spandex cushion electrodes showed superior stability in muscle activation signal acquisition. This research elucidates the connection between electrode performance and factors like layer number and electrode-skin contact area. It suggests a novel approach to electrode design, focusing on layer properties and targeted pressure application on specific sensor areas, rather than uniformly increasing sleeve pressure.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.661-667
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• 2014

Background Tissue expansion is an effective and valuable technique for the reconstruction of large skin lesions and scars. This study aimed to evaluate the applicability and safety of a newly designed skin expanding bioreactor system for maximizing the graft area and minimizing the donor site area. Methods A computer-controlled biaxial skin bioreactor system was used to expand skin in two directions while the culture media was changed daily. The aim was to achieve an expansion speed that enabled the skin to reach twice its original area in two weeks or less. Skin expansion and subsequent grafting were performed for 10 patients, and each patient was followed for 6 months postoperatively for clinical evaluation. Scar evaluation was performed through visual assessment and by using photos. Results The average skin expansion rate was $10.54%{\pm}6.25%$; take rate, $88.89%{\pm}11.39%$; and contraction rate, $4.2%{\pm}2.28%$ after 6 months. Evaluation of the donor and recipient sites by medical specialists resulted in an average score of 3.5 (out of a potential maximum of 5) at 3 months, and 3.9 at 6 months. The average score for patient satisfaction of the donor site was 6.2 (out of a potential maximum of 10), and an average score of 5.2 was noted for the recipient site. Histological examination performed before and after the skin expansion revealed an increase in porosity of the dermal layer. Conclusions This study confirmed the safety and applicability of the in vitro skin bioreactor, and further studies are needed to develop methods for increasing the skin expansion rate.