• Archives of Plastic Surgery
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• 제42권2호
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• pp.150-158
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• 2015

Background Fat is widely used in soft tissue augmentation. Nevertheless, it has an unpredictably high resorption rate. Clinically, external expansion with negative pressure is used to increase fat graft survival. In this study, fat graft recipient sites were preconditioned by external application of negative pressure in order to test for improvements in vascularity and fat graft survival. Methods Negative pressure was applied randomly to either the left or right dorsal ear of 20 New Zealand male white rabbits at a pressure of -125 mm Hg. The negative pressure was removed one week after the skin perfusion was measured. The skin flap at each ear was elevated, and 1 g of fat was grafted above the dorsal perichondrium. After one week, the fat weight, microvessel density, mature vessel density of the skin and fat, and amount of glycerol released were measured. Three months after the grafting, the same measurements were performed, with the exception of glycerol release. Results The fat survival rate of the experimental group ($75.4%{\pm}3.9%$) was higher than that of the control group ($53.1%{\pm}4.3%$) (P<0.001). Skin perfusion was higher in the experimental group. The glycerol release in the experimental group was significantly higher than in the control. The microvessel density of the skin and fat was significantly higher in the experimental group. Three months after the grafting, the skin and fat mature vessel density was significantly higher in the experimental groups. Conclusions Negative pressure prior to fat grafting increased the vascularity of the recipient site, and, accordingly, enhanced fat graft survival.

• Archives of Plastic Surgery
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• 제35권6호
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• pp.716-722
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• 2008

Purpose: Split or full thickness skin graft is generally used to reconstruct the palmar skin and soft tissue defect after release of burn scar flexion contracture of hand. As a way to overcome and improve aesthetic and functional problems, the authors used the preserved superficial fat skin(PSFS) composite graft for correction of burn scar contracture of hand. Methods: From December of 2001 to July of 2007, thirty patients with burn scar contracture of hand were corrected. The palmar skin and soft tissue defect after release of burn scar contracture was reconstructed with the PSFS composite graft harvested from medial foot or below lateral and medial malleolus, with a preserved superficial fat layer. To promote take of the PSFS composite graft, a foam and polyurethane film dressing was used to maintain the moisture environment and Kirschner wire was inserted for immobilization. Before and after the surgery, a range of motion was measured by graduator. Using a chromameter, skin color difference between the PSFS composite graft and surrounding normal skin was measured and compared with full thickness skin graft from groin. Results: In all cases, the PSFS composite graft was well taken without necrosis, although the graft was as big as $330mm^2$(mean $150mm^2$). Contracture of hand was completely corrected without recurrence. The PSFS composite graft showed more correlations and harmonies with surrounding normal skin and less pigmentation than full thickness skin graft. Donor site scar was also obscure. Conclusion: The PSFS composite graft should be considered as a useful option for correction of burn scar flexion contracture of hand.

• Archives of Plastic Surgery
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• 제46권5호
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• pp.414-420
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• 2019

Background Congenital muscular torticollis (CMT) is characterized by persistent head tilt toward the affected side. No consensus exists regarding the cause of this disorder. In this study, we analyzed various clinical factors in patients with CMT who were treated with surgical release. This analysis enabled us to identify potential causative factors of CMT and to establish a basis for surgical interventions. Methods In total, 584 patients who underwent surgical intervention for CMT from October 2007 to December 2016 were included in this study. Their demographic characteristics, birthrelated factors, and clinical features were analyzed. Results Data from 525 patients were analyzed in this study after exclusion of those with insufficient information. Before birth, 31 patients (5.9%) were diagnosed with oligohydramnios, and 87 (16.6%) had a breech presentation. Seven (1.3%) cases of clavicle fracture and two (0.4%) cases of cephalohematoma were noted at birth. Before surgery, 397 patients (75.6%) underwent physiotherapy and 128 patients (24.4%) did not. The duration of physiotherapy ranged from 1 to 50 months (average, 6 months). Conclusions Our study shows that 16.6% of the CMT patients presented in the breech position, which is a much higher rate than that observed in the general population (3%-4%). We hypothesize that being in the breech position as a fetus appears to exert a significant influence on shortening and fibrosis of the sternocleidomastoid muscle.

• Archives of Plastic Surgery
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• 제47권6호
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• pp.622-625
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• 2020

Corner mouth lift is in increasing demand among young patients in East Asia. Although various surgical methods exist for corner mouth lift, many patients are reluctant to undergo surgery due to fears of postsurgical scarring. We present a new technique aimed at reducing postoperative scarring. The technique involves triangular excision of the corner of the mouth and incision of the commissure with transposition of a lateral vermilion flap to lift the corner of the mouth. The muscle around the corner of the mouth is dissected to release tension. The corner mouth lift was successfully performed in all patients. It can be effectively used even in patients, such as young Asian women, who are susceptible to hypertrophic scars.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
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• pp.7-10
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• 2008

Heat release characteristics of live fire load are an important parameter for performance oriented fire safety design of a building. While investigations have been carried out on the fire load and its burning behavior in office, residential and commercial buildings and so on, little effort has been paid for the rational treatment of fire load in post office buildings in Japan. In this report, burning behavior of typical combustible objects in post office buildings are studied by measuring heat release rates of plastic palettes with and without postal envelopes or packages and special containers loading numbers of palettes. The test results suggest that dynamic heat release rate is highly dependent on the condition of palettes especially if they load appropriate amount of postal envelopes or not.

• Membrane and Water Treatment
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• 제13권1호
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• pp.21-28
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• 2022

The use of plastics in our everyday lives have been drastically increased during the last few decades. However with the usage of commercial plastic products there is a possibility of microplastic consumption, due to the fragmentation of the products. Additionally, the potential for microplastic ingestion may also be increased by using damaged products. Hence, the current study was conducted to understand the potential release of micro/nano plastics and organic matter from damaged teabags. To check the leakage tendency, the amount of damage to the tea bags from 1-10 cm were tested along with temperatures of 25-70℃, and exposure times from 5 min to 1 hr was tested. Release of fibrous micro/nanoplastics, and organic leachate from the damaged teabags were observed to understand the outflow conditions. Results showed that with the increased degree of damage, temperature, and exposure time increased the release of fiberous matter, where the increase of temperature, and exposure time increased organic leachate. Additional analysis confirmed the leachate of nylon polymers into the heated water.

• 해양환경안전학회지
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• 제27권3호
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• pp.439-446
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• 2021

Environmental damage caused by marine plastic debris occurs and has become a major contributor to marine pollution. This study analyzed the current state of marine plastic debris pollution and proposed essential strategies to reduce damage. To assess the current state of pollution arising from marine plastic debris, this study investigated the properties of plastic debris, reviewed case studies of ecological impacts, and examined the inflow and distribution of marine plastic debris. The results of this study indicate that the major deleterious effects of marine plastics are entanglement and ingestion. In addition, the amount of plastic waste entering the sea was estimated to be 230 Mt in 2015 and may increase to 554 Mt in 2050. In this study, three key strategies were proposed to reduce damage and preserve the ecosystem, including: 1) removing plastic debris in the marine environment, 2) limiting the release of plastic debris to the marine environment, and 3) preventing damage to humans and marine life from plastic debris. To minimize the environmental damage caused by marine plastic debris, the proposed response strategies should be implemented in parallel.

• Archives of Plastic Surgery
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• 제35권3호
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• pp.235-242
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• 2008

Purpose: Due to increasing interest in the treatment of spinal cord injuries, many histopathological studies have been conducted to prove that many neurotrophic factors including growth hormone are important for regeneration of the injured spinal cord. Growth hormone has to be given everyday, however, and this negatively affects compliance in clinical trials. Recently, the invention of sustained release growth hormone (SRGH) that can be given just once a week may both help the regeneration of injured spinal cord and, at the same time, be more compliant and convenient for clinical patients. Methods: In this study, thirty 7-week-old female Spraque-Dawley rats were subjected to a weight-driven impact spinal cord injury. They were divided into 3 groups and Group I and II were injected with SRGH once a week for 4 weeks; Group I were injected into the injured spinal cord area, while Group II were injected into the peritoneal cavity. Meanwhile, Group III were injected with normal saline solution. The functional outcome was evaluated using the Basso-Beattie-Bresnahan motor rating score and the inclined plane test was done 4 weeks after the first injection. Histopathological examination was performed at the same time and the amount of residual white matter was measured in all groups. Results: After 4 weeks, Groups I and II showed greater improvement than Group III(the control group) in the functional test. In the control group, invasion of atypical phagocytes, axonal degeneration, edema and cavity formation in the posterior site of spinal cord gray matter was observed in histopatholgical examination. The rate of residual white matter in Group III was less than in the other groups. Conclusion: Data showed significant functional and histopathological improvement in the groups treated with SRGH into the spinal and peritoneal cavity compared with the control group. SRGH is therefore beneficial because it helps with regeneration of the injured spinal cord and improves the compliance and convenience of patients.

• Advances in materials Research
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• 제5권4호
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• pp.299-318
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• 2016

Analytical investigations were performed of a longitudinal crack representing a cylindrical surface in circular shafts loaded in torsion with taking into account the non-linear material behavior. Both functionally graded and multilayered shafts were analyzed. It was assumed that the material is functionally graded in radial direction. The mechanical behavior of shafts was modeled by using non-linear constitutive relations between the shear stresses and shear strains. The fracture was studied in terms of the strain energy release rate. Within the framework of small strain approach, the strain energy release rate was derived in a function of the torsion moments in the cross-sections ahead and behind the crack front. The analytical approach developed was applied to study the fracture in a clamped circular shaft. In order to verify the solution derived, the strain energy release rate was determined also by considering the shaft complimentary strain energy. The effects were evaluated of material properties, crack location and material non-linearity on the fracture behavior. The results obtained can be applied for optimization of the shafts structure with respect to the fracture performance. It was shown that the approach developed in the present paper is very useful for studying the longitudinal fracture in circular shafts in torsion with considering the material non-linearity.

• 한국산업융합학회 논문집
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• 제2권2호
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• pp.131-137
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• 1999

Package crack caused by the soldering process in the surface mounting plastic package is evaluated by applying the energy release rate criterion. The package crack formation depend on various parameters such as chip set, chip size, package thickness, package width, material properties and the moisture content etc. The effects of chip set and the other parameters were estimated during the analysis of package cracks which were located in the edge of the upper interface of the chip and the lower interlace of the die pad. From the results, it could be obtained that the more significant parameters to effect the chip set are chip width.