• Archives of Plastic Surgery
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• 제35권1호
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• pp.1-6
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• 2008

Purpose: In tissue engineering, it is important that the scaffolds have high affinity with cells for making efficient use of cells. The authors studied the binding affinity of human adipose stem cells(ASCs) to micronized acellular dermal matrix(alloderm) using biotin and avidin linkages.Methods: Human ASCs were harvested from adipose tissue obtained by abdominoplasty. ASCs($1{\times}10^4$, $5{\times}10^4$, $1{\times}10^5$, $5{\times}10^5$, $1{\times}10^6$, $5{\times}10^6$ cells) were attached to micronized alloderm(1mg) in three groups; 1) control group in which no ASCs and alloderm was treated; 2) serum group in which alloderm was exposed to fetal bovine serum; and 3) biotin group in which biotinylated cells were attached to biotinylated alloderm. The binding affinities were determined 1 day after making ASC-alloderm complexes. The proliferation rates were determined by XTT assays in 4, 7, 14, and 21 days and scanning electron microscopic examination was performed in 7 and 21 days after culture of ASC-alloderm complexes.Results: The binding affinities of the biotin group were significantly increased in all cell concentrations. Maximum binding affinity was observed at $5{\times}10^4/mg$ of micronized dermal matrix in biotin group. The viabilities were lowest in biotin group in contrast to binding affinity, but the difference was not significant. SEM showed well attachment of cells to micronized dermal matrix in all groups. Conclusion: The use of avidin/biotin facilitated human ASCs attaching to micronized acellular dermal matrix. This attachment would not disturb adipose stem cells viabilities. The present study suggests that avidin/ biotin can be used as making efficient use of cells in adipose tissue engineering.

• Archives of Plastic Surgery
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• 제50권4호
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• pp.335-339
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• 2023

It is undeniable that a significant number of patients who want to improve their facial appearance is increasingly interested in nonsurgical procedures. Without a doubt, the use of autologous fat could not be left out as a magnificent alternative for nasal modeling simply because of four influential factors: ease of collection, compatibility, the temporality of the results, and safety. This work describes an innovative alternative technique for nasal modeling using micrografts enriched with adipose-derived mesenchymal stem cells (ASCs). With this technique, fat was collected and divided into two samples, nanofat and microfat. Nanofat was used to isolate the ASCs; microfat was enriched with ASCs and used for nasal modeling. Lipoinjection was performed in a supraperiosteal plane on the nasal dorsum. Through a retrolabial access, the nasal tip and base of the columella were lipoinjected. We consider that nonsurgical nasal modeling using micrografts enriched with ASCs can be an attractive and innovative alternative. This technique will never be a substitute for surgical rhinoplasty. It can be performed in a minor procedure area with rapid recovery and return to the patient's daily activities the next day. If necessary, the procedure can be repeated.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.18-20
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• 2018

This paper proposes a new pair of Active Snubber Cells (ASCs) which can fully provide soft switching for a Floating-output Double Boost Converter (FDBC). Besides that, the introduced ASCs are applicable for all basic DC-DC converters. Main switches of the FDBC turn on and off with ZVS. However, the main diodes are ZCS turned off. Furthermore Snubber switches are turned on and off with ZCS and ZVS respectively. It worthy to mention also that the soft switching for snubber diodes of the presented cells is achieved. A 1.5kW, 100kHz prototype of the FDBC with the proposed ASCs was built and evaluated; and the maximum attained efficiency is 97.3%.

• 대한전자공학회논문지TC
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• 제48권9호
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• pp.17-26
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• 2011

무선 네트워크 기술 및 모바일 컴퓨팅 기기의 발전과 함께 웹 서비스 기술이 발전하여 유비쿼터스 환경에서 새로운 서비스가 출현하게 되었다. 이러한 서비스들은 홈, 사무실, 공항, 전시장 등과 같은 위치 환경과 깊은 관계가 있으며, 위치환경에 따라 차별화된다. 사용자의 환경정보에 따라 다양한 지역서비스를 사용하는데 필요한 프로그램들이 사용자의 기기에 동적으로 전달되어지고, 지역에 따라 분산된 다양한 서비스들을 효과적으로 관리해 주는 시스템이 요구된다. 본 논문에서는 편리하게 서비스 선택을 할 수 있으며 유용한 서비스를 사용자에게 제공해 줄 수 있는 자동 서비스 구성 시스템을 제안한다. 제안한 시스템은 사용자가 지역 서비스 존에 들어가게 되면 모바일 기기에 자동으로 지역서비스 프로그램을 설치하고 지역서비스를 제공하여 준다. 또한 본 시스템은 분산된 지역서비스를 원격에서 효율적으로 관리할 수 있으며, 원격 관리자, 서비스 게이트웨이, 모바일 기기로 구성되어 있다. 본 시스템을 802.11b 무선 네트워크와 OSGi 프레임워크 기반으로 구현하였다.

• 한국실내디자인학회논문집
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• 제17권2호
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• pp.111-121
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• 2008

In recent years, Korean population aged 65 and over has grown faster(7.2% in 2000, 14.4% projected in 2018 and 20.0% in 2026) than the other age groups and average life expectancy has increased from 65.8 years in 1980 to 75.9 years in 2000. The Aging Simulation Center(ASC) was built for people to give educational chance for further understanding of the elderly and the environment for the aged. People are able to recognize the changes including hearing loss, vision changes, and changes in the ability to touch and move after experiencing the simulated daily life of older persons. In general, ASC is composed of residential setting area and exhibition area of daily commodities for the elderly and care person. Currently, there are four ASCs in Korea. The purpose of this study is to evaluate the characteristics of space design and design elements of ASCs and to suggest design implementation for better residential environment for the elderly. For the research purpose, design characteristics such as floor plans and spatial design elements of three ASCs were analyzed and compared. As a whole, space design of three ASCs was almost same without distinguished characteristics. The major finding of this study indicates that the ASC is considerably helpful environment to understand aging. However, some of design elements such as lighting should be supplemented for safety issue. It is recommended for future design of ASC to include exterior space including outdoor stairs, paths and roads and so on. In addition, reception and preparation area should be arranged with universally designed furniture.

• 대한두개안면성형외과학회지
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• 제21권4호
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• pp.211-218
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• 2020

Autologous fat grafts are widely used in soft-tissue augmentation and reconstruction. To reduce the unpredictability of fat grafts and to improve their long-term survival, cell-assisted lipotransfer (CAL) was introduced. In this alternative method, autologous fat is mixed and grafted with stromal vascular fraction cells or adipose-derived stem/stromal cells (ASCs). In regenerative medicine, ASCs exhibit excellent therapeutic potential and are also simple to harvest. Although the efficacy of CAL has been demonstrated in experimental and clinical research, studies on its safety in terms of oncologic risk have reported inconclusive results. In order to establish CAL as a viable stem cell therapeutic approach, it will be necessary to demonstrate its oncologic safety in basic and clinical studies. Doing so could transform the paradigm of clinical strategy and practice for the treatment of a wide variety of diseases.

• Applied Microscopy
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• 제50권
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• pp.26.1-26.3
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• 2020

The biocompatible polyurethane acrylate (PUA) nanopillars were fabricated by soft lithography using three different sizes of nanobeads (350, 500, and 1000 nm), and the human adipose-derived stem cells (hASCs) were cultured on the nanopillars. The hASCs and their various behaviors, such as cytoplasmic projections, migration, and morphology, were observed by high resolution images using a scanning electron microscope (SEM). With the accurate analysis by SEM for the controlled sizes of nanopillars, the deflections are observed at pillars fabricated with 350- and 500- nm nanobeads. These high-resolution images could offer crucial information to elucidate the complicated correlations between nanopillars and the cells, such as morphology and cytoplasmic projections.

• Archives of Plastic Surgery
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• 제45권2호
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• pp.128-134
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• 2018

Background Non-syndromic craniosynostosis causes craniofacial asymmetry and may persist after cranioplasty. These postoperative asymmetries are primarily depressions. In some cases, patients may be subjected to pranks and harassment by their peers, affecting their psychosocial development. We propose lipoinjection enriched with adipose stem cells (ASCs) to treat the sequelae of craniosynostosis in the fronto-orbital and temporal complex in cranioplasty patients, with the goal of improving the appearance of the upper third of the face. Methods Twelve children (four boys and eight girls) between 4 and 8 years of age (mean age, 6 years) in the postoperative period after treatment for plagiocephaly, brachycephaly, and trigonocephaly were included, with a follow-up period of 1 to 18 months. Fat tissue was obtained from the lower abdomen, and ASCs were isolated using the Yoshimura technique. Lipoinjection was performed using several mini-approaches to ensure adequate distribution. Results Two different scales were used to evaluate the aesthetic outcomes. At 6 months, three plastic surgeons independent of the study classified the results using a Likert scale. The patients' parents categorized the results using a visual analog scale at 6, 9, and 18 months. R esults were favorable on both scales, as the patients' facial appearance improved and they reported increased happiness and self-esteem due to their remodeled facial appearance. Conclusions We suggest that lipoinjection enriched with ASCs is a good alternative for correcting asymmetry of the fronto-orbital and temporal contour in patients with sequelae of craniosynostosis. This treatment will help boost patients' self-esteem starting at an early age.

• BMB Reports
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• 제53권2호
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• pp.118-123
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• 2020

Cardiac regeneration with adult stem-cell (ASC) therapy is a promising field to address advanced cardiovascular diseases. In addition, extracellular vesicles (EVs) from ASCs have been implicated in acting as paracrine factors to improve cardiac functions in ASC therapy. In our work, we isolated human cardiac mesenchymal stromal cells (h-CMSCs) by means of three-dimensional organ culture (3D culture) during ex vivo expansion of cardiac tissue, to compare the functional efficacy with human bone-marrow derived mesenchymal stem cells (h-BM-MSCs), one of the actively studied ASCs. We characterized the h-CMSCs as CD90^low, c-kit^negative, CD105^positive phenotype and these cells express NANOG, SOX2, and GATA4. To identify the more effective type of EVs for angiogenesis among the different sources of ASCs, we isolated EVs which were derived from CMSCs with either normoxic or hypoxic condition and BM-MSCs. Our in vitro tube-formation results demonstrated that the angiogenic effects of EVs from hypoxia-treated CMSCs (CMSC-Hpx EVs) were greater than the well-known effects of EVs from BM-MSCs (BM-MSC EVs), and these were even comparable to human vascular endothelial growth factor (hVEGF), a potent angiogenic factor. Therefore, we present here that CD90^lowc-kit^negativeCD105^positive CMSCs under hypoxic conditions secrete functionally superior EVs for in vitro angiogenesis. Our findings will allow more insights on understanding myocardial repair.

• Journal of Korean Neurosurgical Society
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• 제63권2호
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• pp.153-162
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• 2020

Spinal cord injury (SCI) is one of the most devastating conditions and many SCI patients suffer neurological sequelae. Stem cell therapies are expected to be beneficial for many patients with central nervous system injuries, including SCI. Adult stem cells (ASCs) are not associated with the risks which embryonic stem cells have such as malignant transformation, or ethical problems, and can be obtained relatively easily. Consequently, many researchers are currently studying the effects of ASCs in clinical trials. The environment of transplanted cells applied in the injured spinal cord differs between the phases of SCI; therefore, many researchers have investigated these phases to determine the optimal time window for stem cell therapy in animals. In addition, the results of clinical trials should be evaluated according to the phase in which stem cells are transplanted. In general, the subacute phase is considered to be optimal for stem cell transplantation. Among various candidates of transplantable ASCs, mesenchymal stem cells (MSCs) are most widely studied due to their clinical safety. MSCs are also less immunogenic than neural stem/progenitor cells and consequently immunosuppressants are rarely required. Attempts have been made to enhance the effects of stem cells using scaffolds, trophic factors, cytokines, and other drugs in animal and/or human clinical studies. Over the past decade, several clinical trials have suggested that transplantation of MSCs into the injured spinal cord elicits therapeutic effects on SCI and is safe; however, the clinical effects are limited at present. Therefore, new therapeutic agents, such as genetically enhanced stem cells which effectively secrete neurotrophic factors or cytokines, must be developed based on the safety of pure MSCs.