• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.224-231
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• 2006

agents used for enhancing mechanical properties of porous natural scaffolds, reduces biocompatability of the scaffolds, due to their inherent cytotoxicity. In this study, scaffolds which was composed of chitosan, alginate and gelatin were cross-linked by using heat treatment instead of cross-linking agent and mechanical properties of the cross-linked scaffold were investigated. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed that cross-linking of heat-treated scaffold was formed via amide or ester linkage between the polymer chains. The heat-treated scaffold had interconnected pores with mean diameter of 100~200 m and showed more than two fold increase of water uptake in comparison with chemically cross-linked scaffold. Tensile strength of the heat-treated scaffold increased up to 130% compared to non cross-linked scaffold and average maximum elongation was 11.3%. The porous cross-linked scaffold with the improved mechanical property may be suitable as a biocompatable scaffold for tissue engineering.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.159-160
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• 2006

A novel approach to the manufacture of biocompatible ceramic scaffold for tissue engineering using micro-stereolithography system is introduced. Micro-stereolithography is a newly proposed technology that enables to make a 3D micro structure. The 3D micro structures made by this technology can have accurate and complex shape within a few micron error. Therefore, the application based on this technology can vary greatly in nano-bio fields. Recently, tissue-engineering techniques have been regarded as alternative candidate to treat patients with serious bone defects. So many techniques to design and fabricate 3D scaffolds have been developed. But the imperfection of scaffold such as random pore size and porosity causes a limitation in developing optimum scaffold. So scaffold development with controllable pore size and fully interconnected shape have been needed for a more progress in tissue engineering. In this paper, bone scaffold was developed by applying the micro-stereolithography to the mold technology. The scaffold material used was HA(Hydroxyapatite) nano powder. HA is a type of calcium phosphate ceramic with similar characteristic to human inorganic bone component. The bone scaffold made by HA is expected, in the near future, to be an efficient therapy for bone defect.

• Polymer(Korea)
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• v.32 no.2
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• pp.163-168
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• 2008

Biomedical scaffold for tissue regeneration was fabricated by one of rapid prototyping processes, bioplotting system, with a biodegradable and biocompatible poly($\varepsilon$-carprolactone)(PCL). Through dynamic mechanical test, it was observed that the PCL scaffold manufactured by the bioplotting process has the superior mechanical properties compared to the conventional scaffold fabricated by a salt-leaching process, and the plotted scaffold could be employed as a potential scaffold to regenerating hard and soft tissue. The plotted scaffold was consisted of porous structures. which were interconnected with each pore to help cells be easily adhered and proliferated in the wall of pore tunnels, and metabolic nutrients can be transported within the matrix. By using the plotting system, we could adjust the pore size, porosity, strand pitch, and, strand diameter of PCL scaffolds, which were important parameters to control mechanical properties of the scaffolds, and consequently we could determine that the mechanically controlled scaffolds could be used as a matching scaffold for any required mechanical properties of the target organ. The fabricated 3D PCL scaffold showed enough possibility as a 3D biomedical scaffold, which was cell-cultured with chondrocytes.

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.258-263
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• 2007

This study was carried out to investigate the effects of number of the lower scaffold limbs on tree growth, light penetration, fruit yield, and fruit quality in slender spindle in 6-year-old 'Fuji'/M.9 apple trees. With regard to the growth by the numbers of the lower scaffold limbs, the width of the tree was wide and the growth of new shoots was increased when the number of the lower scaffold limbs was five. Compare with other treatments, five lower scaffold limbs showed high light-interception on the upper (150 cm above the ground) and middle (100 cm above the ground) canopy. There was no difference in the total number of the flower buds of the spurs according to the number of scaffold limbs, but the number and cross section area of flower bud on the lower canopy (120 cm above the ground) were increased where the number of the lower scaffold limbs was five. Fruit yield was highest in the treated with five lower scaffold limbs and fruit weight tended to increase where the number of the lower scaffold limbs was five or eight. With regard to fruit quality, there showed no difference in fruit shape index, firmness, acid content, Hunter L and b value according to the location of canopy and the number of the lower scaffold limbs, but the content of soluble solids was highest treated with five lower scaffold limbs. Hunter a value indicating fruit color was found to be highest treated with five lower scaffold limbs whose light interception was highest.

• Korean Journal of Biological Psychiatry
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• v.17 no.3
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• pp.119-126
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• 2010

Synaptic adhesion molecules mediate synapse formation, maturation and maintenance. These proteins are localized at synaptic sites in neuronal axons and dendrites. These proteins function as a bridge of synaptic cleft via interaction with another synaptic adhesion molecules in the opposite side. They can interact with scaffold proteins via intracellular domain and recruit many synaptic proteins, signaling proteins and synaptic vesicles. Scaffold proteins function as a platform in dendritic spines or axonal terminals. Recently, many genetic studies have revealed that synaptic adhesion molecules and scaffold proteins are important in neurodevelopmental disorders, psychotic disorders, mood disorders and anxiety disorders. In this review, fundamental mechanisms of synapse formation and maturation related with synaptic adhesion molecules and scaffold proteins are introduced and their psychiatric implications addressed.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.77-81
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• 2020

In this paper, we create scaffold defect classification models using machine learning based data. We extract the characteristic from collected scaffold external images using USB camera. SVM, KNN, MLP algorithm of machine learning was using extracted features. Classification models of three type learned using train dataset. We created scaffold defect classification models using test dataset. We quantified the performance of defect classification models. We have confirmed that the SVM accuracy is 95%. So the best performance model is using SVM.

• Journal of the Semiconductor & Display Technology
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• v.19 no.2
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• pp.26-30
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• 2020

In this paper, we studied the problem if the experiment number occurring in order to identify defect in scaffold. We need to change each of the 5 print factor to predict defect when printing disk type scaffold using FDM 3d printer. So then the number of scaffold print will be more than 100,000 times. This experiment number is difficult to perform in the field. In order to solve this problem, we have produced a prediction model based on machine learning multiple linear regression using print conditions and defect scaffold data for print conditions. The prediction model produced was verified through experiments. The verification confirmed that the error was less than 0.5 %. We have confirmed that satisfied within the target margin of error 5 %.

• Journal of the Semiconductor & Display Technology
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• v.16 no.4
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• pp.25-29
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• 2017

In this paper, we have studied the deformation problem of the scaffold caused by the FDM type 3D printer. The Practical TRIZ technique was used to solve the deformation problem of the scaffold generated from the adhesion surface between the scaffold and the bed. The Practical TRIZ methodology was used to derive the solution and the experiment was conducted on the derived solution. As a result of evaluating the experimental results obtained for the solution, it was found that the deformation of the scaffold was much improved to the satisfactory level.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.871-876
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• 2022

In the construction industry, fatal accidents related to scaffolds frequently occur. To prevent such accidents, scaffolds should be carefully monitored for their safety status. However, manual observation of scaffolds is time-consuming and labor-intensive. This paper proposes a method that automatically analyzes the installation status of scaffold joints based on images acquired from a Unmanned Aerial Vehicle (UAV). Using a deep learning-based object detection algorithm (YOLOv5), scaffold joints and joint components are detected. Based on the detection result, a two-stage rule-based classifier is used to analyze the joint installation status. Experimental results show that joints can be classified as safe or unsafe with 98.2 % and 85.7 % F1-scores, respectively. These results indicate that the proposed method can effectively analyze the joint installation status in UAV-acquired scaffold images.

• Macromolecular Research
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• v.12 no.4
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• pp.367-373
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• 2004

We have developed a rigorous heat treatment method to improve the biocompatibility of chitosan as a tissue-engineered scaffold. The chitosan scaffold was prepared by the controlled freezing and lyophilizing method using dilute acetic acid and then it was heat-treated at 110$^{\circ}C$ in vacuo for 1-3 days. To explore changes in the physicochemical properties of the heat-treated scaffold, we analyzed the degree of deacetylation by colloid titration with poly(vinyl potassium sulfate) and the structural changes were analyzed by scanning electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, wide-angle X-ray diffractometry (WAXD), and lysozyme susceptibility. The degree of deacetylation of chitosan scaffolds decreased significantly from 85 to 30% as the heat treatment time increased. FT-IR spectroscopic and WAXD data indicated the formation of amide bonds between the amino groups of chitosan and acetic acids carbonyl group, and of interchain hydrogen bonding between the carbonyl groups in the C-6 residues of chitosan and the N-acetyl groups. Our rigorous heat treatment method causes the scaffold to become more susceptible to lysozyme treatment. We performed further examinations of the changes in the biocompatibility of the chitosan scaffold after rigorous heat treatment by measuring the initial cell binding capacity and cell growth rate. Human dermal fibroblasts (HDFs) adhere and spread more effectively to the heat-treated chitosan than to the untreated sample. When the cell growth of the HDFs on the film or the scaffold was analyzed by an MTT assay, we found that rigorous heat treatment stimulated cell growth by 1.5∼1.95-fold relative to that of the untreated chitosan. We conclude that the rigorous dry heat treatment process increases the biocompatibility of the chitosan scaffold by decreasing the degree of deacetylation and by increasing cell attachment and growth.