• Archives of Plastic Surgery
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• v.46 no.4
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• pp.330-335
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• 2019

Background The use of anatomic implants has improved the aesthetic results of breast surgery; however, implant malrotation is an uncommon, but serious complication of these procedures. Nevertheless, little research has explored implant adhesion. In this study, we investigated adhesion between the expander and the capsule. Methods Seventy-nine cases of immediate breast reconstruction via two-stage implant-based reconstruction performed between September 2016 and November 2017 were evaluated. Mentor CPX4 expanders were used in 14 breasts, and Natrelle expanders in 65. We analyzed areas of adhesion on the surfaces of the tissue expanders when they were exchanged with permanent implants. We investigated whether adhesions occurred on the cephalic, caudal, anterior, and/or posterior surfaces of the expanders. Results Total adhesion occurred in 18 cases, non-adhesion in 15 cases, and partial adhesion in 46 cases. Of the non-adhesion cases, 80% (n=12) were with Mentor CPX4 expanders, while 94.4% (n=17) of the total adhesion cases were with Natrelle expanders. Of the partial adhesion cases, 90.7% involved the anterior-cephalic surface. The type of tissue expander showed a statistically significant relationship with the number of attachments in both univariate and multivariate logistic regression analyses (P<0.001) and with total drainage only in the univariate analysis (P=0.015). Conclusions We sought to identify the location(s) of adhesion after tissue expander insertion. The texture of the implant was a significant predictor of the success of adhesion, and partial adhesion was common. The anterior-cephalic surface showed the highest adhesion rate. Nevertheless, partial adhesion suffices to prevent unwanted rotation of the expander.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.2
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• pp.87-92
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• 2015

The injection molding process is widely used in the production of most plastic products. In order to make metal-colored plastic products like those found in modern luxury home alliances, metallic pigments are mixed with a basic resin material for injection molding. However, process control for metal-colored plastic products is extremely difficult due to the non-uniform melt flow of the metallic resin pigments. In this study, the effect of process parameters on the quality of a metal-colored plastic product is evaluated. A rapid mold cooling method using a compressed cryogenic fluid is also proposed to decrease the content of undesired compounds within the plastic product.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.32-37
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• 2001

In the present industry, there are necessary to cut not only iron metals but also non-ferrous metals such as aluminum, brass, plastic and wood(Paulownia). therefore it had been made the studies of non-ferrous metals by many scientists. we hope this kind of study will continue. The purpose of this study is to conduct the basic experiment about influencing of change the side rake angle at turning of non-ferrous metals. As the results, the surface roughnesses were on the increase with a increase of side-rake angle at the case of the plastic, brass, aluminum, and paulownia.

• Journal of Korean Elementary Science Education
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• v.33 no.2
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• pp.401-414
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• 2014

The purpose of this study is to investigate the elementary preservice teachers' conceptions about 'plastics' focusing on non-polar property from a National University of Education. For the study, the views about plastics, relative shapes of a water droplet on plastic or glass material, and relative shapes of water surface in the plastic or glass measuring cylinder were surveyed from the preservice teachers. And the responses were analyzed based on the patterns. The results from the study are as follows: First, most preservice teachers were well aware of the plastic products which are used in daily life. Second, the responses concerning the reason why plastics can be used commonly were divided into 2 categories with 14 sub-level groups. However relatively few preservice teachers mentioned regarding 'chemical stability' and 'conductivity', which are associated with the plastics' non-polar property. Third, it was found that 50 participants (30.1%) had 'Scientific conception (Sc)', 38 (22.9%) had 'Partial-scientific conception (Ps)', 66 (39.8%) had 'Misconception (Mc)', and 12 (7.2%) had 'No conception (Nc)' on the subject of the relative shapes of a water droplet. Fourth, the distribution patterns and the ratio of the preservice teachers' conception on the survey question 3 concerning the relative shapes of water surface were quite similar to those of the survey question 2. So it was concluded that overall understanding level of the preservice teachers was pretty low on the subjects of the relative polarities of the plastic, glass, and water as well as their interactions. Fifth, the distribution percentile of 'Sc'/'Ps'/'Mc'/'Nc' was not related with the gender but highly correlated with preservice teachers' academic field and their science subjects taken in high school. Based on the results from the study, some educational guidelines were suggested.

• Medical Lasers
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• v.8 no.2
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• pp.59-63
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• 2019

Background and Objectives High-intensity focused ultrasound (HIFU) has been developed as an effective, non-invasive, skin-tightening method in response to the increasing demand for improvements in skin laxity and tightening with minimal risk and recovery time. This study evaluated the efficacy and safety of HIFU for non-invasive skin tightening of crow's feet wrinkles, with the aim of determining how long the tightening can be maintained. Materials and Methods Between January and March 2019, 21 female patients with crow's feet wrinkles were treated with HIFU. The treatment involved 200 shots, three times every 2 weeks. Three blinded, experienced plastic surgeons and patients evaluated satisfaction at 2 weeks after the first procedure, 2 weeks after the second procedure, 2 weeks after the third procedure, and 6 weeks after the first procedure based on photographs according to the Global Aesthetic Improvement Scale (GAIS). The Friedman test was used to compare data. Results Of the 21 patients treated using HIFU, one was lost to follow-up for nonstudy-related reasons. Therefore, 20 patients were evaluated and ranged in age from 28 to 48 years. Plastic surgeons' GAIS scores were 2.6, 2.3, 1.7, and 1.3 and patients' GAIS scores were 2.6, 2.2, 1.8, and 1.4 at 2 weeks after the first procedure, 2 weeks after the second procedure, 2 weeks after the third procedure, and 6 weeks after the third procedure. No serious adverse effects were observed. Conclusion The aging face with crow's feet wrinkles can be improved by using HIFU, while minimizing epidermal and dermal injury.

• Archives of Craniofacial Surgery
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• v.24 no.5
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• pp.223-229
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• 2023

Background: Preauricular sinus (PAS) is a common congenital anomaly, and complete excision is recommended to prevent recurrence. However, PAS has a high recurrence rate as a result of incomplete removal due to the high variability of the sinus ramifications, making its treatment challenging. In this study, we standardized the surgical procedure to reduce the complications and recurrence rate and compared the postoperative results between the non-standardized and the standardized groups. Methods: This retrospective study included 97 patients (120 ears) who had undergone PAS excision by a single surgeon between October 2014 and September 2022 and underwent at least 6 months of follow-up. After October 2018, all patients were treated using the standardized method, which comprised the use of magnifying glasses, exploration with a lacrimal probe, the use of methylene blue staining, and excision of a piece of surrounding normal tissue and related cartilage in continuity with the specimen. There were 38 patients (45 ears) in the non-standardized group and 59 patients (75 ears) in the standardized group. Results: Recurrence was observed in six of 120 ears, indicating an overall recurrence rate of 5.0%. Recurrence occurred in five ears (11.1%) in the non-standardized group and one ear (1.3%) in the standardized group. The standardized group had a significantly lower recurrence rate (p= 0.027) than the non-standardized group. Conclusion: We defined a standardized sinectomy protocol and used it for the surgical treatment of PAS. With this standardized method, we were able to reduce the rates of complications and recurrence without the use of a long incision.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.293-296
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• 2010

Purpose: NTM (non tuberculous mycobacteria) is rare cause of surgical site infection after plastic surgery in immunocompetent patients. There are some reports about NTM infection after body contouring procedure from Latin America. But, there is no report in Korea. The purpose of this article is to report 2 patients with soft tissue infection caused by NTM after body contouring procedure. Methods: Two young female patients exhibited signs of inflammation and abscess after body contouring procedure. One patient underwent liposuction. The other underwent HPL (hypotonic pharmacologic lipo-dissolution) injection. Results: The result of tissue cultures were positive for NTM. All patients responded to the combined therapeutic approach. Conclusion: The goal of this article is to raise awareness among plastic surgeons who may encounter such patients in their practice. NTM should be included in the differential diagnosis of surgical site infection after body contouring surgery.

• Geotechnical Engineering
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• v.13 no.5
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• pp.133-144
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• 1997

It was proved from the viscosity test for deposits of debris flows(Kim and Seo, 1997) that the property of debris flows could be represented as Bingham plastic model. Based on this bahavior, numerical analysis for the movement of debris flows is carried out by using a computer progran Polyflow which huts been developed for the analysis of the behavior of non-Newtonian fluid. The numerical results obtained from two sites agree well with the movement predicted by an empirical formula. It can be concluded, therefore. that this scheme can be used for the analysis of the movement of debris flow.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.143-150
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• 1999

The LRFD Specification defines two sets of limiting width-to-thickness ratios. On the basis of these limiting values, steel sections we subdivided into three categories: compact, noncompact, and slender sections. A compact section is capable of developing a fully plastic stress distribution (plastic moment), and can sustain rotations approximately three times beyond the yield before the possibility of local buckling arises. Noncompact sections can develop the yield stress before local buckling occurs. They may not, however, resist local buckling at the strain levels required to develop the fully plastic stress distribution. In this paper, 1-Type girders of a 2 span continuous steel bridge are divided into compact and non-compact sections and analyzed. In the design process, an optimization skill was adopted and ADS, a Fortran program for Automated Design Synthesis, was used.

• Structural Engineering and Mechanics
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• v.61 no.2
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• pp.275-282
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• 2017

The Fleck-Hutchinson theory on strain gradient plasticity (SGP), proposed in Adv. Appl Mech 33 (1997) 295, has recently been reformulated by adopting the strategy of decomposing the second order strain presented by Lam et al. in J Mech Pays Solids 51 (2003) 1477. The newly built SGP satisfies the non negativity of plastic dissipation, which is still an outstanding issue in other SGP theories. Furthermore, it explicitly shows how elastic strain gradients and corresponding elastic characteristic length scales come into play in general elastic-plastic loading histories. In this study, the relation between elastic length scales and plastic length scales is investigated by taking wire torsion as an example. It is concluded that the size effects arising when two sets of length scales are of the same order are essentially elastic instead of plastic.