• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.192-203
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• 2004

The AA5182/polypropylene/AA5182 (AA/PP/AA) sandwich sheets have been developed for the application for automotive body panels in the future light weight vehicles with significant weight reduction. It has been reported that the 5182 aluminum sheet shows Luders band because of dissolved Mg atoms that causes fabrication process problem, especially surface roughness. The examination of serration behavior has been made after the tensile deformation of the AA/PP/AA sandwich sheets as well as that of the 5182 aluminum skin at room and elevated temperatures. All sandwich sheets and the 5182 aluminum skin showed serration phenomena on their flow curves. However, the magnitude of the serration was significantly diminished in the sandwich sheet with the high volume fraction of the polypropylene core. According to the results of the surface roughness analysis after the tensile test, the sandwich sheet evidently showed lower Luders band depth than the 5182 aluminum skin. Strain rate sensitivity, m-value, of the 5182 aluminum skin was -0.006. By attaching this skin with polypropylene core which has relatively large positive value, 0.050, m-value of the sandwich sheets was changed to the positive value. The serration reduction of the sandwich sheets was quantitatively investigated in the point of the effect on the polypropylene core thickness variation, that on the strain rate sensitivity. It was found that the serration reduction degree from the experimental results of the sandwich sheet was higher than that from the calculated values by the rule of mixture based on volume fraction of the skins and the core.

• Elastomers and Composites
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• v.39 no.3
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• pp.193-208
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• 2004

Morphology of injection molded polymer blend was investigated by experimental and theoretical approach. In experiments, the effects of injection speed and injection temperature on the morphology of injection molded MPPO/Nylon 6 blend were investigated. The morphology distribution across the part thickness was clearly observed in injection molded blend. We could observe several distinct regions across the thickness of molded part: skin layer, subskin layer and core region. The skin layer where the dispersed phase is fine and highly deformed to the flow direction is observed to be located near the part surface. The subskin layer located at inner region of the skin layer also observed. In the subskin layer, the dispersed phase is coarser than that of skin layer and deforms to the flow direction. Based on the experimental results, the calculation scheme to predict the morphology of injection molded polymer blend was suggested. The morphology of injection molded polymer blend could be predicted in corporation with the result of flow analysis obtained from commercial software for injection molding process and the theory of drop behavior under the flow. The suggested calculation scheme could predict the effect of injection conditions on the morphology of injection molded parts.

• Archives of Craniofacial Surgery
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• v.22 no.2
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• pp.85-92
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• 2021

Background: Patients with secondary deformities associated with unilateral cleft lip and nose might also suffer from nostril stenosis due to a lack of tissue volume in the nostril on the cleft side. Here, we used full-thickness skin grafts (FTSGs) to reduce nostril stenosis and various methods for skin volume augmentation. We compared the changes in the symmetry of both nostrils before and after surgery. Methods: From February 2016 to January 2020, 34 patients underwent secondary cheiloplasty and open rhinoplasty for secondary deformities of the unilateral cleft lip and nose with nostril stenosis. FTSG was used on the nostril floor, nasal columella, and alar inner lining. The measured nasal profile included the nostril surface, nostril circumference, width of the nostril floor, and distance from the alar-facial groove to the nasal tip. The "overlap area," which was defined as the largest overlapping area when the image of the cleft nostril was flipped to the left and right and overlaid on the image of the normal side nostril, was also calculated. The degree of symmetry was evaluated by dividing the value of the cleft side by that of the normal side of each measured profile and expressed as "ratios." Results: The results of all profile ratios, except for the nostril floor width, became significantly close to 1, which represents full symmetry. The overlap area ratio improved from 62.7% to 77.3%, meaning that the length and width of the nostril as well as the overall shape became similar (p< 0.05). Conclusion: When performing cleft rhinoplasty with nostril stenosis, FTSG is useful to achieve symmetry in the nostril size and shape. Skin grafting is simpler to perform than the other types of local flap, and the results are generally satisfactory.

• 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.

• Animal cells and systems
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• v.7 no.1
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• pp.43-47
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• 2003

The skin of the eel goby, Odontamblyopus lacepedii, consists of epidermis, dermis and subcutis. The epidermis has three layers: the outermost layer, middle layer and stratum germinativum. The outermost layer is composed of polygonal cells or rather flattened cells, and mucous gland cells of acid mucopolysaccharides. The middle layer consists mainly of swollen small or voluminous epidermal cells and shows a web-shaped structure. The thickness of the epidermis depends on the various sizes and the number of layers of the swollen cells. Well-developed lymphatic spaces containing lymphocytes exist in the stratum germinativum and small scales are embedded in the dermis. A large number of blood capillaries are present just below the basement membrane, and a definite area giving AB and PAS positive was present between the basement membrane and scales, Taste buds ave distributed on surface of the epidermis at intervals. Considering the structural features of the skin, it may be considered that O. lacepedii is more likely to be related to cutaneous respiration as a dual respiratory system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.189-199
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• 2006

Purpose of study: Partial thickness skin graft is the golden standard regimen for full-thickness skin defect caused by burn or trauma. However, in case of extensive burns of more than 50% of total body surface area, the donor site is not sufficient to cover all defects. As a second choice, allograft, xenograft and synthetic materials have been used to treat skin defect. Among them the amniotic membrane(AM) was used as a biological dressing for centuries because of its potential for wound healing. In this study, quantification of EGF in AM and effect of AM-collagen complex on full thickness skin defects was examined. Materials & Methods: The concentration of EGF in fresh, deep frozen and freeze-dried AM was evaluated by ELISA. EGF-R immunostaining was performed in freeze-dried AM. SD rats weighing 250${\sim}$300g was used for wound healing experiment. Three full thickness skin defects(28mm diameter) were made on dorsal surface of SD rat. The control group was covered by Vaselin gauze and AM-collagen complex and $Terudermis^{(R)}$. was grafted in two other defects. Healing area, Cinamon's score were evaluated before biopsy. Grafted sites were retrieved at 3 days, 1 week, 2 weeks and 4 weeks after operation. H & E and Factor VIII immunohistochemical stain was performed to evaluate the microscopic adhesion and structural integrity and microvessel formation. Results: 1. EGF concentration of fresh, deep frozen and freeze-dried AM showed similar level and EGF-R was stained in epithelial layer of freeze-dried AM. 2. At 4 weeks after grafting, the healing area of AM-collagen and Terudermis group was 99.29${\pm}$0.71% and 99.19${\pm}$0.77 of original size. However, that of control group was 24.88${\pm}$2.90. 3. The Cinamon's score of AM-Collagen and $Terudermis^{(R)}$. group at 4 weeks was 15.6${\pm}$1.26 and 14.6${\pm}$3.13 and that of control group was 3.7${\pm}$0.95. Significant difference was observed among control and experimental groups(p<0.05). 4. Histologic examination revealed that AM protected leukocyte infiltration and epithelial migration was nearly completed at 4 weeks. $Terudermis^{(R)}$. group showed mild neutrophil infiltration until 2 weeks and completion of epithelization at 4 weeks. Control group showed massive leukocyte infiltration until 4 weeks. 5. Microvessels were increased sharply at 1 week and control group at 1 and 4 week showed significant differences with $Terudermis^{(R)}$. group of same interval(p<0.05) but no differences were found with AM group(p<0.05). Conclusion: EGF and EGF-R were well preserved in freeze-dried AM. AM attached to collagen acted as excellent biologic dressing which had similar effect with $Terudermis^{(R)}$. AM showed anti-inflammatory action and healing was completed at 4 weeks after full-thickness skin defect.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.469-472
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• 2010

Purpose: Aplasia Cutis Congenita (ACC) is a rare disease characterized by the focal defect of the skin at birth, frequently involving scalp, but it may affect any region of the body. There are no etiology known but some conditions such as intrauterine vascular ischemia, amniotic adherences and viral infections are associated. The ideal treatment for the ACC is not known. Superficial and relatively small sized defects (< $3{\times}5\;cm$) may heal spontaneously and large defects related with risks of infection and bleeding may require aggressive surgical treatment. Hyalomatrix$^{(R)}$ is a bilayer of an esterified hyaluronan scaffold beneath a silicone membrane. It has been used as a temporary dermal substitute to cover deep thickness skin defect and has physiological functions derive from the structural role in extracellular matrix and interaction with cell surface receptor. This material has been used for the wound bed pre-treatment for skin graft to follow and especially in uncooperative patient, like a newborn, this could be a efficient and aseptic way of promoting granulation without daily irritative wound care. For this reason, using Hyalomatrix$^{(R)}$ for the treatment of ACC was preferred in this paper. Methods: We report a case of a newborn with ACC of the vertex scalp and non-ossified partial skull defect. The large sized skin and skull defect ($6{\times}6\;cm$) was found with intact dura mater. No other complications such as bleeding or abnormal neurologic sign were accompanied. Escharectomy was performed and Hyalomatrix$^{(R)}$ was applied for the protection and the induction of acute wound healing for 3 months before the split-thickness skin graft. During the 3 months period, the dressing was renewed in aseptic technique for every 3 weeks. The skin graft was achieved on the healthy granulation bed. Results: The operative procedure was uneventful without necessity of blood transfusion. Postoperative physical examination revealed no additional abnormalities. Regular wound management was performed in out-patient clinic and the grafted skin was taken completely. No other problems developed during follow-up. Conclusion: Hyalomatrix$^{(R)}$ provides protective and favorable environment for wound healing. The combination of the use of Hyalomatrix$^{(R)}$ and the skin graft will be a good alternative for the ACC patients with relatively large defect on vertex.

• Archives of Plastic Surgery
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• v.33 no.3
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• pp.376-378
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• 2006

Basal cell carcinoma(BCC) is malignant epithelial neoplasm arising from either basal cells or pluripotential appendageal cells of the epidermis. BCC is the most common cutaneous malignancy, especially in sun-exposed sites, such as head and neck. But its occurrence on the finger is very rare. We experienced a case of BCC arising on the dorsal surface of the middle finger of a young woman. This case is not associated with any predisposing factors such as basal cell nevus syndrome, trauma, or preexistent dermatosis. Following surgical removal of the lesion, the defect was covered with full-thickness skin graft. The patient has presented no sign of relapse for 1 year of clinical follow-up. We report this rare case of BCC in terms of age and location.

• Applied Microscopy
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• v.52
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• pp.8.1-8.7
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• 2022

The Korean trident goby, Tridentiger brevispinis, lives in adverse habitats that can easily become hypoxic due to low precipitation, regional dry periods, and high amounts of solar radiation. Histological and morphometric studies revealed the goby's specialized skin (35.4-150.0㎛ in thickness), consisting of an epidermis and dermis. The thicker epidermis comprises an outermost surface layer (having taste buds, stratified fattened cells, mucous cells, pigment cells, and stratified polygonal cells), middle layer (having stratified polygonal cells), and stratum germinativum (stratified columnar cells). In particular, the dermis has scales, well-developed vascularization, and a few blood capillaries just above the basement membrane, and a reduced diffusion distance was present in the lateral body. Consequently, adaptations such as thicker epidermis, well-developed vascularization, few blood capillaries, and a reduced diffusion distance may provide cutaneous respiration for survival in poorly oxygenated water during the periodic dry season.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.1
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• pp.21-28
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• 2006

Purpose: The purpose of this study is to find a optimal beam spoiler condition on the dose distribution near the surface, when treating a squamous cell carcinoma of the head and neck and a lymphatic region with 10 MV photon beam. The use of a optimal spoiler allows elivering high dose to a superficial tumor volume, while maintaining the skin-sparing effect in the area between the surface to the depth of 0.4 cm. Materials and Methods: The lucite beam spoiler, which were a tissue equivalent, were made and placed between the surface and the photon collimators of linear accelerator. The surface-dose, the dose at the depth of 0.4 cm, and the maximum dose at the dmax were measured with a parallel-plate ionization chamber for $5{\times}5cm\;to\;30{\times}30cm^2$ field sizes using lucite spoilers with different thicknesses at varying skin-to-spoiler separation (SSS). In the same condition, the dose was measured with bolus and compared with beam spoiler. Results: The spoiler increased the surface and build-up dose and shifted the depth of maximum dose toward the surface. With a 10 MV x-ray beam and a optimal beam spoiler when treating a patient, a similer build-up dose with a 6 MV photon beam could be achieved, while maintaining a certain amount of skin spring. But it was provided higher surface dose under SSS of less than 5 cm, the spoiler thickness of more than 1.8 cm or more, and larger field size than $20{\times}20cm^2$ provided higher surface dose like bolus and obliterated the spin-sparing effect. the effects of the beam spoiler on beam profile was reduced with increasing depths. Conclusion: The lucite spoiler allowed using of a 10 MV photon beam for the radiation treatment of head and neck caner by yielding secondary scattered electron on the surface. The dose at superficial depth was increased and the depth of maximum dose was moved to near the skin surface. Spoiling the 10 MV x-ray beam resulted in treatment plans that maintained dose homogeneity without the consequence of increased skin reaction or treat volume underdose for regions near the skin surface. In this, the optimal spoiler thickeness of 1.2 cm and 1.8 cm were found at SSS of 7 cm for $10{\times}10cm^2$ field. The surface doses were measured 60% and 64% respectively. In addition, It showed so optimal that 94% and 94% at the depth of 0.4 cm and dmax respectively.