Radially patterned polycaprolactone nanofibers as an active wound dressing agent

Dongwoo Shin,Min Sup Kim,양채은,이원재,노태석,백우열 대한성형외과학회 2019 Archives of Plastic Surgery Vol.46 No.5

Background The objectives of this study were to design polycaprolactone nanofibers with a radial pattern using a modified electrospinning method and to evaluate the effect of radial nanofiber deposition on mechanical and biological properties compared to non-patterned samples. Methods Radially patterned polycaprolactone nanofibers were prepared with a modified electrospinning method and compared with randomly deposited nanofibers. The surface morphology of samples was observed under scanning electron microscopy (SEM). The tensile properties of nanofibrous mats were measured using a tabletop uniaxial testing machine. Fluorescence-stained human bone marrow stem cells were placed along the perimeter of the radially patterned and randomly deposited. Their migration toward the center was observed on days 1, 4, and 7, and quantitatively measured using ImageJ software. Results Overall, there were no statistically significant differences in mechanical properties between the two types of polycaprolactone nanofibrous mats. SEM images of the obtained samples suggested that the directionality of the nanofibers was toward the central area, regardless of where the nanofibers were located throughout the entire sample. Florescence images showed stronger fluorescence inside the circle in radially aligned nanofibers, with significant differences on days 4 and 7, indicating that migration was quicker along radially aligned nanofibers than along randomly deposited nanofibers. Conclusions In this study, we successfully used modified electrospinning to fabricate radially aligned nanofibers with similar mechanical properties to those of conventional randomly aligned nanofibers. In addition, we observed faster migration along radially aligned nanofibers than along randomly deposited nanofibers. Collectively, the radially aligned nanofibers may have the potential for tissue regeneration in combination with stem cells.

Radially patterned polycaprolactone nanofibers as an active wound dressing agent

Shin, Dongwoo,Kim, Min Sup,Yang, Chae Eun,Lee, Won Jai,Roh, Tai Suk,Baek, Wooyeol Korean Society of Plastic and Reconstructive Surge 2019 Archives of Plastic Surgery Vol.46 No.5

Background The objectives of this study were to design polycaprolactone nanofibers with a radial pattern using a modified electrospinning method and to evaluate the effect of radial nanofiber deposition on mechanical and biological properties compared to non-patterned samples. Methods Radially patterned polycaprolactone nanofibers were prepared with a modified electrospinning method and compared with randomly deposited nanofibers. The surface morphology of samples was observed under scanning electron microscopy (SEM). The tensile properties of nanofibrous mats were measured using a tabletop uniaxial testing machine. Fluorescence-stained human bone marrow stem cells were placed along the perimeter of the radially patterned and randomly deposited. Their migration toward the center was observed on days 1, 4, and 7, and quantitatively measured using ImageJ software. Results Overall, there were no statistically significant differences in mechanical properties between the two types of polycaprolactone nanofibrous mats. SEM images of the obtained samples suggested that the directionality of the nanofibers was toward the central area, regardless of where the nanofibers were located throughout the entire sample. Florescence images showed stronger fluorescence inside the circle in radially aligned nanofibers, with significant differences on days 4 and 7, indicating that migration was quicker along radially aligned nanofibers than along randomly deposited nanofibers. Conclusions In this study, we successfully used modified electrospinning to fabricate radially aligned nanofibers with similar mechanical properties to those of conventional randomly aligned nanofibers. In addition, we observed faster migration along radially aligned nanofibers than along randomly deposited nanofibers. Collectively, the radially aligned nanofibers may have the potential for tissue regeneration in combination with stem cells.

Medical Dispute

Dongwoo Shin 대한외과학회 2019 대한외과학회 학술대회 초록집 Vol.2019 No.10

의무기록과 의료분쟁

Dongwoo Shin 대한외과학회 2019 대한외과학회 학술대회 초록집 Vol.2019 No.10

Violation of Ohm’s law in a Weyl metal

Shin, Dongwoo,Lee, Yongwoo,Sasaki, M.,Jeong, Yoon Hee,Weickert, Franziska,Betts, Jon B.,Kim, Heon-Jung,Kim, Ki-Seok,Kim, Jeehoon Nature Publishing Group, a division of Macmillan P 2017 Nature materials Vol.16 No.11

Ohm’s law is a fundamental paradigm in the electrical transport of metals. Any transport signatures violating Ohm’s law would give an indisputable fingerprint for a novel metallic state. Here, we uncover the breakdown of Ohm’s law owing to a topological structure of the chiral anomaly in the Weyl metal phase. We observe nonlinear I–V characteristics in Bi<SUB>0.96</SUB>Sb<SUB>0.04</SUB> single crystals in the diffusive limit, which occurs only for a magnetic-field-aligned electric field (E∥B). The Boltzmann transport theory with the charge pumping effect reveals the topological-in-origin nonlinear conductivity, and it leads to a universal scaling function of the longitudinal magnetoconductivity, which completely describes our experimental results. As a hallmark of Weyl metals, the nonlinear conductivity provides a venue for nonlinear electronics, optical applications, and the development of a topological Fermi-liquid theory beyond the Landau Fermi-liquid theory.

Sarcopenia Definition, diagnosis & treatment

( Dongwoo Shin ) 한국정맥경장영양학회 2016 한국정맥경장영양학회 학술대회집 Vol.2016 No.-

Not All Deals are Created Equal :Two Distinct Roles of Sales Promotion on Consumer’s Shopping Plans

Shin, Dongwoo(신동우) 한국경영교육학회 2015 경영교육연구 Vol.30 No.2

본 논문은 목적 수립 및 달성과정에 대한 이론들을 바탕으로 소비자가 쇼핑계획을 수립하고 실행하는 과정에서 판매촉진 자극물이 끼치는 영향에 대한 이론적 틀을 제공하고 있다. 본 논문에서 제시된 모델은 판매촉진 자극물이 소비자의 구매행동에 독립적인 두 경로(형성 vs. 방해) 를 통해서 영향을 미칠 수 있음을 주장하고 있다. 형성경로는 사전에 제공된 판매 촉진 자극물 이 여러개의 실행의도의 조합으로 이루어진 쇼핑 계획을 수립하는데 필요한 동인과 정보를 제공하는 과정에 대해 서술하고 있다. 반면 방해경로는 구매 현장에서 제공되는 경쟁사의 판매 촉진 자극물이 소비자가 사전에 구성한 쇼핑 계획의 실행을 방해하는 외부 자극으로 작동하는 과정을 설명하고 있다. 소비자의 행동(action)/상태(state) 마음가짐은 형성과 방해 과정에서 판매 촉진 자극물이 미치는 영향의 크기를 변화시키는 조절 변수로 제시되었다. The authors propose an action-oriented framework that emphasizes the influence of sales promotions in a consumer’s goal-striving process. The model hypothesizes that a sales promotion stimulus influences a consumer’s goal striving process via two routes (formation and disturbance of implementation intentions). Formation refers to a process which a sales promotion motivates a consumer to form a new set of implementation intentions.Disturbance refers to a process that a sales promotion influences a consumer’s buying behavior by breaking his/her current implementation intentions. Action orientation mindset (i.e., deliberate- vs. implemental- mindset) is introduced as a moderating variable that influences the formation and disturbance processes and the relationship between past behavior and current behavior.

Serially expanded flap use to treat large hairless scalp lesions

Shin, Dongwoo,Kim, Yong Hun,Song, Han Gyeol,Hong, Jong Won Korean Cleft Palate-Craniofacial Association 2019 Archives of Craniofacial Surgery Vol.20 No.6

Hairless scalp areas can occur due to trauma, tumors, or congenital disease. This aesthetically unpleasing condition can lead to psychosocial distress, and thin skin flaps may be prone to scarring. Treating the hairless scalp by simple excision is challenging because of skin tension. Tissue expanders are a good option for hairless scalp resurfacing. However, a single expansion may be inadequate to cover the entire defect. This report describes good results obtained using a serial resurfacing method involving re-expansion of the flap with a tissue expander to treat two patients with large lesions: one due to aplasia cutis congenital and another who underwent dermatofibrosarcoma protuberance resection. The results suggest that scalp resurfacing by serial tissue expansion using a tissue expander can be used for extensive lesions.

Simulation Study of Electromagnetic Forming in Aluminum alloy Sheet

Dongwoo Shin,Youngsuk Kim,Arun Kumar,Rajesh Appaturai 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.5

Selective Growth and Structural Analysis of Regular MnO Nanooctapods Bearing Multiple High-Index Surface Facets.

Shin, Dongwoo,Kim, Mijong,Song, Hyunjoon Wiley-VCH 2015 Chemistry, an Asian journal Vol.10 No.8

<P>Although numerous morphologies of MnO nanostructures have been reported, an exact structural analysis and mechanistic study has been lacking. In the present study, the formation of regular MnO octapods was demonstrated in a simple procedure, comprising the thermal decomposition of manganese oleate. Because of their structural uniformity, an ideal three-dimensional model was successfully constructed. The eight arms protruded from the cubic center with tip angles of 38° and surface facets of {311} and {533} with rounded edges. The concentrations of oleate and chloride ions were the determining factors for the octapod formation. Selective coordination of the oleate ions to the {100} faces led to edge growth along the <111> direction, which was then limited by the chloride ions bound to the high-index surface facets. These structural and mechanistic analyses should be helpful for understanding the complex nanostructures and for tuning their structure-related properties.</P>