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Application of Natural Resource-derived Biomaterials with Nanotechnology and 3D Printing Techniques
선우훈 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
There are many trials to regenerate one’s defected organs or tissues by tissue engineered techniques. To date, synthetic polymers are frequently used as base materials. However, such polymers have unexpected side effects, such as cytotoxicity and genotoxicity. To solve these problems, biomaterials derived from natural resources are addressed as alternatives. We introduce the application of natural resource-derived biomaterials, such as equine bone powder and chitosan, with nanomaterials and 3D printing techniques. At first, equine bone powder and chitosan were solely used for tissue regeneration. The application of nanomaterials, such as graphene, and electrospun nanofiber with natural resource-derived biomaterials resulted in enhanced tissue regenerations. Finally, we tried to apply natural resources into 3D printed tissue reconstruction. Their application is expected to fulfill the limitation of conventional synthetic polymer-based therapies.
온실에서 방울토마토 수확작업시 작업자의 생리학적 및 생체역학적 반응 측정
선우훈,임기택,김장호,손현목,정종훈 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.3
Physiological signals such as body temperature, heart rate, blood pressure and heart rate variability and biomechanical workload for stress analysis were investigated during the cherry tomato harvesting work in a greenhouse. The skin temperatures raised 0.05℃/min, 0.03℃/ min, and 0.08 ℃/min in standing, stooping and squatting postures, respectively. Breath rate significantly increased from 18 to 28 breaths/min during the cherry tomato harvesting work. As the heart rate during the work ranged from about 72 to 110 beats/min (bpm), the cherry tomato harvesting work appeared to be a light intensity task of less than 110 bpm. The worker’s average energy consumption rate in three positions during 43 min working time was 65.74 kcal (91 kcal/h in 70 kg). This was a light intensity of work, compared to 75 kcal/h in 70 kg of basic metabolic energy consumption rate of a worker with 70 kg weight; The maximum shear force on the disk (L5/ S1) due to static workload in the cherry tomato harvesting work was 446 N in the stooping posture, 321 N in the squatting posture and 287 N in the standing posture. Acute stress index expressed with the heart rate variability, increased parasympathetic activation up to about 70 while workers were doing most agricultural work in this study. This study provided a system to measure quantitatively workers’ physiological change, kinematics and kinetic factors without any restrictions of space in the greenhouse works.
논문 : 정보처리 및 복합기술 ; 온실에서 방울토마토 수확작업시 작업자의 생리학적 및 생체역학적 반응 측정
선우훈 ( H. Seonwoo ),임기택 ( K. T. Lim ),김장호 ( J. H. Kim ),손현목 ( H. M. Son ),정종훈 ( J. H. Chung ) 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.3
Physiological signals such as body temperature, heart rate, blood pressure and heart rate variability and biomechanical workload for stress analysis were investigated during the cherry tomato harvesting work in a greenhouse. The skin temperatures raised 0.05℃/min, 0.03℃/ min, and 0.08 ℃/min in standing, stooping and squatting postures, respectively. Breath rate significantly increased from 18 to 28 breaths/min during the cherry tomato harvesting work. As the heart rate during the work ranged from about 72 to 110 beats/min (bpm), the cherry tomato harvesting work appeared to be a light intensity task of less than 110 bpm. The worker`s average energy consumption rate in three positions during 43 min working time was 65.74 kcal (91 kcal/h in 70 kg). This was a light intensity of work, compared to 75 kcal/h in 70 kg of basic metabolic energy consumption rate of a worker with 70 kg weight; The maximum shear force on the disk (L5/ S1) due to static workload in the cherry tomato harvesting work was 446 N in the stooping posture, 321 N in the squatting posture and 287 N in the standing posture. Acute stress index expressed with the heart rate variability, increased parasympathetic activation up to about 70 while workers were doing most agricultural work in this study. This study provided a system to measure quantitatively workers` physiological change, kinematics and kinetic factors without any restrictions of space in the greenhouse works.
손현목,선우훈,김장호,임기택,정종훈 한국농업기계학회 2013 바이오시스템공학 Vol.38 No.2
Purpose: The purpose of this study is to provide analysis of physiological, biomechanical responses occurring from the operation to lifting or twist lifting task appears frequently in agricultural work. Methods: This study investigated the changes of physiological factors such as heart rate, heart rate variability (HRV) and biomechanical factors such as physical activity and kinetic analysis in the task of twisting at the waist while lifting. Results: Heart rates changed significantly with the workload. The result indicated that the workload of 2 kg was light intensity work, and the workload of 12 kg was hard intensity work. Physical activity increased as the workload increased both on wrist and waist. Besides, stress index of the worker increased with the workload. Dynamic load to herniated discs was analyzed using inertial sensor, and the angular acceleration and torque increased with the workload. The proposed measurement system can measure the recipient’s physiological and physical signals in real-time and analyzed 3-dimensionally according to the variety of work load. Conclusions: The system we propose will be a new method to measure agricultural workers’ multi-dimensional signals and analyze various farming tasks.
임기택,박수현,선우훈,정필훈,김장호,정종훈 한국농업기계학회 2013 바이오시스템공학 Vol.38 No.1
Purpose: The present study aimed at image processing methods for automatic cell pattern recognition and morphological analysis for tissue engineering applications. The primary aim was to ascertain the novel algorithm of adaptive brightness correction from microscopic images for use as a potential image analysis. Methods: General microscopic image of cells has a minor problem which the central area is brighter than edge-area because of the light source. This may affect serious problems to threshold process for cell-number counting or cell pattern recognition. In order to compensate the problem, we processed to find the central point of brightness and give less weight-value as the distance to centroid. Results: The results presented that microscopic images through the brightness correction were performed clearer than those without brightness compensation. And the classification of mixed cells was performed as well, which is expected to be completed with pattern recognition later. Beside each detection ratio of hBMSCs and HeLa cells was 95% and 92%, respectively. Conclusions: Using this novel algorithm of adaptive brightness correction could control the easier approach to cell pattern recognition and counting cell numbers.
Cellulose-based Nanocrystals: Sources and Applications via Agricultural Byproducts
서유리,김진우,선우훈,김장호,정종훈,임기택 한국농업기계학회 2018 바이오시스템공학 Vol.43 No.1
Purpose: Cellulose nanocrystals (CNCs) are natural polymers that have been promoted as a next generation of new, sustainable materials. CNCs are invaluable as reinforcing materials for composites because they can impart improved mechanical, chemical, and thermal properties and they are biodegradable. The purpose of this review is to provide researchers with information that can assist in the application of CNCs extracted from waste agricultural byproducts (e.g. rice husks, corncobs, pineapple leaves). Methods & Results: This paper presents the unique characteristics of CNCs based on agricultural byproducts, and lists processing methods for manufacturing CNCs from agricultural byproducts. Various mechanical treatments (microfluidization and homogenization) and chemical treatments (alkali treatment, bleaching and hydrolysis) can be performed in order to generate nanocellulose. CNC-based composite properties and various applications are also discussed. Conclusions: CNC-based composites from agricultural byproducts can be combined to meet end-use applications such as sensors, batteries, films, food packaging, and 3D printing by utilizing their properties. The review discusses applications in food engineering, biological engineering, and cellulose-based hydrogels.
장경제,박상배,이주오,홍영걸,선우훈,임기택,김장호,정종훈 한국농업기계학회 2023 바이오시스템공학 Vol.48 No.4
Introduction Collagen and other natural polymers including hyaluronic acid and chitosan (CS) are common additives for improving the bone forming capacity and retain the structures of xenografts. The topography of the cell-attaching region on implants has a significant role in the cell behavior. To control the topography of calcium phosphate composites (CPCs) in the cell-attaching regions, equine bone powders (EBPs) with various sizes and CS solutions were used to fabricate CPCs. A correlation between the particle size distribution of the equine bone-derived calcium phosphate composites (EB-CPCs) and behavior of mesenchymal stem cells was observed. The EBPs were classified according to the granule size. The main crystal was hydroxyapatite. Results The results of the surface roughness measurements revealed that in the groups containing hydroxyapatite particles with sizes of 5 μm, 50 μm, and 100 μm, the Rz values were 23.199, 43.274, and 69.701 μm, respectively. The ultimate compressive strengths for the groups with hydroxyapatite sizes of 5 μm, 50 μm, and 100 μm were 1.98 ± 0.058 MPa, 1.36 ± 0.17 MPa, and 1.96 ± 0.14 MPa, respectively. A cell viability analysis revealed that a higher Rz led to elongated shape, resulting in an enhanced cell proliferation. A lower Rz led to rounded shape, resulting in an increased osteogenic differentiation. Conclusion In conclusion, control of the powder particle size in the fabrication of CPCs is an important factor affecting osteogenesis.