• Macromolecular Research
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• v.15 no.1
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• pp.65-73
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• 2007

Chitosan, fibroin, and hydroxyapatite are natural biopolymers and bioceramics that are biocompatible, biodegradable, and resorb able for biomedical applications. The highly porous, chitosan-based, bioceramic hybrid composite, chitosanlfibroin-hydroxyapatite composite, was prepared by a novel method using thermally induced phase separation. The composite had a porosity of more than 94% and exhibited two continuous and different morphologies: an irregularly isotropic pore structure on the surface and a regularly anisotropic multilayered structure in the interior. In addition, the composite was composed of an interconnected open pore structure with a pore size below a few hundred microns. The chemical composition, pore morphology, microstructure, fluid absorptivity, protein permeability, and mechanical strength were investigated according to the composition rate of bioceramics to biopolymers for use in tissue engineering. The incorporation of hydroxyapatite improved the fluid absorptivity, protein permeability, and tenacity of the composite while maintaining high porosity and a suitable microstructure.

• Journal of Biomedical Engineering Research
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• v.33 no.4
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• pp.207-212
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• 2012

It is widely known that sciatic nerve injury (SNI) can negatively affect the biomechanical characteristics of the musculoskeletal system. However, there were no studies that evaluated and compared denervated side with another side limb at the same time. In this study, sixteen male 12-week-old mice were allocated into two groups: HEMI (Right Sciatic nerve denervated) and CON (Control). Both limbs were scanned using micro-CT at 0 week and 4 weeks. There were significant differences in relative variation (RV) of BMD and all structural parameters compared CON and HEMI in right tibia (p < 0.05). Tb.Th and Tb.Sp distributions were differed CON with HEMI in right tibia. In left tibia, there were significant differences in RV of BMD (p < 0.05) and Tb.Sp distribution. These result means that SNI can induce bone loss in the both side tibiae. However, there was a different profile of bone loss between left and right tibiae.

• Rapid Communication in Photoscience
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• v.1 no.2
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• pp.35-37
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• 2012

Photoinduced electron-transfer process of 1,8-naphthalimide-linker-trimethylsilane (NI-O3-TMS, O3 = 3,6,9-trioxaundecyl) and NI-O3 has been investigated using the transient absorption measurements in $CH_3CN$ and $CH_3CN/H_2O$. The excitation of NI-O3-TMS in $CH_3CN$ produced the NI radical anion ($NI^{{\cdot}-}$) with a transient absorption band around 413 nm, via the intermolecular electron-transfer between NI moieties in the excited singlet state. In contrast, in a protic polar solvent mixture of $CH_3CN/H_2O$, a proton abstraction process occurred from $NI^{{\cdot}-}$ to generate the NI ketyl radical ($NIH^{\cdot}$), which showed a transient absorption band around 405 nm. The decay time constants of $NIH^{\cdot}$ were quite long compared to those of $NI^{{\cdot}-}$ in $CH_3CN$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.4
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• pp.193-197
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• 2018

The ratio of the period of a diffractive element to the input beam size is a critical parameter in a diffractive beam shaper. We measured and calculated the Fraunhofer diffraction patterns of a periodic hologram with an input beam size similar to the period of the hologram. The measured intensities show very complicated patterns and are strongly dependent upon the center position of the laser beam relative to the hologram. Using a diffraction formula for a periodic hologram, we calculated the diffracted light intensities and fit them to the measured ones. The measured and calculated intensities are in good agreement even when the beam diameter of the incident laser is similar to the period of the hologram. We can therefore use this formula to estimate the output of a periodic beam shaper even under such an extreme condition.

• International Journal of Korean Welding Society
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• v.2 no.2
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• pp.7-13
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• 2002

A comparison of the welding performance of ship hull structural steels has been made. The weldability of steels especially designed for laser processing was compared to that of conventional hull and structural steels with plate thicknesses up to 12 mm. Autogenous laser beam welding was used to weld butt joints as well as skid and stake welded T-joints. The welds were assessed in accordance with the document "The Classification Societies" Requirements for Approval of $CO_2$ Laser Welding Procedures" Small imperfections in the weld only grew slightly in root bend tests and they only had a minor influence on the fatigue properties of laser fillet welded joints. In Charpy impact tests, the 27 J transition temperature of the weld metal and HAZ ranged from below -60 to $-50^{\circ}C$. The amount of martensite in the weld metal depended on the carbon equivalent of the steel with the highest amounts and highest hardness levels in conventional EH 36 (389 HV 5). Thermomechanically rolled steels contained less martensite and showed a correspondingly lower maximum hardness.ximum hardness.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.222-228
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• 2002

A comparison of the welding performance of ship hull structural steels has been made. The weldability of steels especially designed for laser processing was compared to that of conventional hull and structural steels with plate thicknesses up to 12 mm. Autogenous laser beam welding was used to weld butt joints as well as skid and stake welded T-joints. The welds were assessed in accordance with the document "The Classification Societies′ Requirements for Approval of $CO_2$ Laser Welding Procedures". Small imperfections in the weld only grew slightly in root bend tests and they only had a minor influence on the fatigue properties of laser fillet welded joints. In Charpy impact tests, the 27 J transition temperature of the weld metal and HAZ ranged from below -60 to -5$0^{\circ}C$. The amount of martensite in the weld metal depended on the carbon equivalent of the steel with the highest amounts and highest hardness levels in conventional EH 36 (389 HV 5). Thermomechanically rolled steels contained less martensite and showed a correspondingly lower maximum hardness.

• Journal of Life Science
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• v.26 no.1
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• pp.91-100
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• 2016

Angiogenesis is essential for the pathophysiological processes of embryogenesis, tissue growth, diabetic retinopathy, psoriasis, wound healing, rheumatoid arthritis, cardiovascular diseases, and tumor growth. Inhibition of angiogenesis represents an attractive therapeutic approach for the treatment of angiogenic diseases such as cancer. However, uncontrolled angiogenesis is also necessary for tumor development and metastasis. Inhibition of vascular endothelial growth factor (VEGF) signaling, a critical factor in the induction of angiogenesis, cause robust and rapid changes in blood vessels of tumors and therefore VEGF constitutes a target for such anti-angiogenic therapy. Recently, since natural compounds pose significantly less risk of deleterious side effects than synthetic compounds, a great many natural resources have been assessed for useful substance for anti-angiogenic treatment. Here we evaluated the anti-angiogenic effects of a hot water extract of Scutellaria baicalensis (SBHWE) using in vitro assays and ex vivo animal experiments. Our results show that SBHWE dose-dependently abrogated vascular endothelial responses by inhibiting VEGF-stimulated migration and invasion as well as tube formation in a human umbilical vein endothelial cell (HUVEC) model, without cytotoxicity, as determined by a cell viability assay. Further study revealed that SBHWE prevented VEGF-induced neo-vascularization in a rat aortic ring sprouting model. Taken together, our findings reveal an anti-angiogenic activity of Scutellaria baicalensis and suggest that SBHWE is a novel candidate inhibitor of VEGF-induced angiogenesis.

• The monthly packaging world
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• s.267
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• pp.42-43
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• 2015

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.758.2-758.2
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• 2006

• Science & Technology Policy
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• v.10 no.3 s.123
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• pp.122-127
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• 2000