• Smart Structures and Systems
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• v.7 no.3
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• pp.223-228
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• 2011

An understanding of biomaterials' smart properties and how biocomposite materials are manufactured by cells provides not only bio-inspiration for new classes of smart actuators and sensors but also foundational technology for smart materials and their manufacture. In this case study, I examine the unique smart properties of bone, which are evident at multiple length scales and how they provide inspiration for novel classes of mechanoactive materials. I then review potential approaches to engineer and manufacture bioinspired smart materials that can be applied to solve currently intractable problems such as the need for "smart" body armor or decor cum personal safety devices.

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.1
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• pp.47-59
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• 2015

A bioactive and multifunctional elastin-like polymer (ELP) was produced by genetic engineering techniques to develop new artificial matrices with the ability to mimic the extracellular matrix (ECM). The basic composition of this ELP is a thermo- and pH-sensitive elastin pentapeptide which has been enriched with RGD-containing domains, the RGD loop of fibronectin, for recognition by integrin receptors on their sequence to promote efficient cell attachment. Hydrogels of this RGD-containing polymer were obtained by crosslinking with hexamethylene diisocyanate, a lysine-targeted crosslinker. These materials retain the "smart" nature and temperature-responsive character, and the desired mechanical behavior of the elastin-like polymer family. The influence of the degree of crosslinking on the morphology and properties of the matrices were tested by calorimetric techniques and scanning electron microscopy (SEM). Their mechanical behavior was studied by dynamical mechanical analysis (DMA). These results show the potential of these materials in biomedical applications, especially in the development of smart systems for tissue engineering.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.255-262
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• 2018

Purpose: To obtain the dynamic characteristics (spring stiffness and damping coefficient) of a rubber mount supporting a tractor cabin in order to develop a simulation model of an agricultural tractor. Methods: The KS M 6604 rubber mount test method was used to test the dynamic characteristics of the rubber mount. Of the methods proposed in the standard, the resonance method was used. To perform the test according to the standard, a base excitation test device was constructed and the accelerations were measured. Results: Displacement transmissibility was measured by varying the frequency from 3-30 Hz. The vibration transmissibility at resonance was confirmed, and the dynamic stiffness and damping coefficient of the rubber mount were obtained. The front rubber mount has a spring constant of 1247 N/mm and damping ratio of 3.27 Ns/mm, and the rear rubber mount has a spring constant of 702 N/mm and damping ratio of 1.92 Ns/mm. Conclusions: The parameters in the z-direction were obtained in this study. In future studies, we will develop a more complete tractor simulation model if the parameters for the x- and y-directions can be obtained.

• Biomaterials Research
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• v.22 no.4
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• pp.303-310
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• 2018

Background: Photodynamic therapy (PDT) is photo-treatment of malignant or benign diseases using photosensitizing agents, light, and oxygen which generates cytotoxic reactive oxygens and induces tumour regressions. Several photodynamic treatments have been extensively studied and the photosensitizers (PS) are key to their biological efficacy, while laser and oxygen allow to appropriate and flexible delivery for treatment of diseases. Introduction: In presence of oxygen and the specific light triggering, PS is activated from its ground state into an excited singlet state, generates reactive oxygen species (ROS) and induces apoptosis of cancer tissues. Those PS can be divided by its specific efficiency of ROS generation, absorption wavelength and chemical structure. Main body: Up to dates, several PS were approved for clinical applications or under clinical trials. $Photofrin^{(R)}$ is the first clinically approved photosensitizer for the treatment of cancer. The second generation of PS, Porfimer sodium ($Photofrin^{(R)}$), Temoporfin ($Foscan^{(R)}$), Motexafin lutetium, Palladium bacteriopheophorbide, $Purlytin^{(R)}$, Verteporfin ($Visudyne{(R)}$), Talaporfin ($Laserphyrin^{(R)}$) are clinically approved or under-clinical trials. Now, third generation of PS, which can dramatically improve cancer-targeting efficiency by chemical modification, nano-delivery system or antibody conjugation, are extensively studied for clinical development. Conclusion: Here, we discuss up-to-date information on FDA-approved photodynamic agents, the clinical benefits of these agents. However, PDT is still dearth for the treatment of diseases in specifically deep tissue cancer. Next generation PS will be addressed in the future for PDT. We also provide clinical unmet need for the design of new photosensitizers.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.32.1-32.12
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• 2020

Objectives: To evaluate the polymerization efficiency of a matrix-modified bulk-fill composite, and compare it to a conventional composite which has a similar filler system. The degree of conversion (DC%) and monomer elution were measured over different storage periods. Additionally, fillers' content was examined. Materials and Methods: Cylindrical specimens were prepared, in bulk and incrementally, from Filtek Bulk Fill (B) and Filtek Supreme XTE (S) composites using a Teflon mold, for each test (n = 6). Using attenuated total reflection method of Fourier transformation infrared spectroscopy, DC% was measured after 24 hours, 7 days, and 30 days. Using high-performance liquid chromatography, elution of hydroxyethyl methacrylate, triethylene glycol dimethacrylate, urethane dimethacrylate, and bisphenol-A glycidyl dimethacrylate was measured after 24 hours, 7 days and 30 days. Filler content was examined by scanning electron microscopy (SEM). Data were analyzed using 2-way mixed-model analysis of variance (α = 0.05). Results: There was no significant difference in DC% over different storage periods between B-bulk and S-incremental. Higher monomer elution was detected significantly from S than B. The elution quantity and rate varied significantly over storage periods and between different monomers. SEM images showed differences in fillers' sizes and agglomeration between both materials. Conclusions: Matrix-modified bulk-fill composites could be packed and cured in bulk with polymerization efficiency similar to conventional composites.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.205-212
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• 2001

One of the important characteristics of biological systems os their ability to change im-portant properties in response to small environmental signals. The molecular mechanisms that biological molecules utilize to sense and respond provide interesting models for the development of "smart" polymeric biomaterials with biomimetic properties. An important example of this is the protein coat of viruses, which contains peptide units that facilitate the trafficking of the virus into the cell via endocytosis, then out of the endosome into the cytoplasm, and from there into the nucleus, We have designed a family of synthetic polymers whose compositions have been de-signed to mimic specific peptides on viral coats that facilitate endosomal escape. Our biomimetic polymers are responsive to the lowered pH whinin endosomes, leading to distruption of the en-dosomal membrane and release of important biomolecular druges such as DNA, RNA, peptides and proteins to the cytoplasm before they are trafficked to lysosomes and degraded by lysosomal en-zymes. In this article, we review our work on the design, synthesis and action of such smart, pH-sensitive polymers.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.2
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• pp.119-130
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• 2007

Purpose: This investigation was designed to estimate the flexure strength, density, and microstructure of the colored and uncolored zirconia oxide ceramics for fixed partial denture. Material and Methods: LAVATM All Ceramic(3M-ESPE, USA), Cercon Smart Ceramic(Dentsply, USA), and Z-match Ceramic(DentAim, Korea) were used for this study. All specimen was fabricated by ASTM C1161. After preparing $25{\times}2{\times}1.5mm$ of rectangular column and sitting rectangular column on universal test machine (UTM), external supporting point distance is 20.0 mm, internal supporting point distance is 10.0 mm. Specimen was loaded with 0.2 mm/min of cross head speed until fracture and at the time of broken of specimen, measuring loading value with PC software. Results: The results were obtained as follows: 1. Flexure strength of uncolored zirconia was higher than that of colored zirconia. 2. In uncolored zirconia, flexure strength of LAVATM Ceramic was more higher than the other ceramics, and it showed statistical difference between LAVATM Ceramic and Cercon Smart Ceramic (P<0.05). 3. In colored zirconia, flexure strength of LAVATM Ceramic was more higher than the other ceramics too, but they did not show statistical difference (p>0.05). 4. In Weibull analysis, Characterastic strength was showed highest value to uncolored LAVATM Ceramic and lowest value to Z-match ceramic, and Weibull modulus(m) of uncolored zirconia was higher than that of colored zirconia. 5. In XRD analysis, all group except Z-match showed high peak of t-ZrO2 but they did not show m-ZrO2. Colored zirconia group showed lower peak of t-ZrO2 than that of uncolored zirconia group.

• Journal of Marine Bioscience and Biotechnology
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• v.14 no.2
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• pp.124-132
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• 2022

By-products from fisheries produced in Korea are of the same industrial material as imported raw materials and are valuable resources for marine bioindustries. Securing raw materials for the mass production of functional materials is one of the main objectives for marine bioindustrial development. The use of fishery by-products as raw materials is anticipated to increase rapidly as the biomarket is growing into a promising industry. In this study, data were acquired from an open-source environment to perform exploratory data analysis, and various visualization methods were used to compare fishery production to the production of marine processed products in the year 2020. This study suggested that the amount of seafood processing, types of processing items, and areas where fishery processing residue is generated, should be able to secure hygienic raw material supply in large quantities. Thus far, it has been found that the Gyeonggi-do and Busan province, where HACCP-certified processing facilities are concentrated, and the local government Seafood Cluster and the Smart Aquaculture Cluster are at the forefront of stable, mass production of raw materials.

• Journal of Forest and Environmental Science
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• v.39 no.1
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• pp.40-48
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• 2023

Street trees have been incorporated into urban forests to regulate the microclimate and provide shade as well as provide aesthetic and environmental functions and to evaluate their physiological characteristics. Zelkova serrata is a major tree species that has been planted on various South Korean streets. We determined the physiological characteristics of Z. serrata in street trees of Goyang and Paju in Gyeonggi Province. According to survey sites, net CO₂ assimilation rates was 13.9-16.4 µmol CO₂ m^-2s^-1, chlorophyll fluorescence (Fv/Fm) was 0.80-0.82, and proline contents was showed 3.4-3.7 mg g^-1 FW. The studied trees were assumed to be physiologically stressed, but it was found that Z. serrata was planted as street trees were not significantly stressed when compared to chlorophyll fluorescence responses and proline contents. In the future, the continuous monitoring system is needed to evaluate the physiological characteristics of urban trees.

• The Korea Journal of Herbology
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• v.26 no.2
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• pp.11-15
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• 2011

Objectives : In the present study, the contents of cinnamic acid and cinnamaldehyde in three different parts of Cinnamomi Ramulus (CR) (the whole body, the bark part, and the wood part) was evaluated using UPLC (ultra performance liquid chromatography) in order to investigate a suitable cutting method. Methods : Analysis was performed on SMART LC with UV detector. Reference compounds were separated on Inertsil ODS-4 column ($2.1mm{\times}50mm$, $3{\mu}m$, GL Science, Japan) using isolation elution with water and acetonitrile each containing acetic acid at a flow rate of $500{\mu}L/min$. Additionally, samples of CR were purchased from pharmacy of medicinal herb. Results : The correlation coefficients of the cinnamic acid and cinnamaldehyde levels showed good linearity ($r^2{\geq}0.9999$) over the linear ranges. Furthermore, the bark part exhibited higher concentration levels of reference compounds than the wood part in all samples. In addition the bark exfoliation rates in oblique and perpendicular-long cut samples of CR were lower than the perpendicular-short cut samples. Conclusions : These results suggested that the optimal cutting method would be able to reduce the bark exfoliation. Therefore, the oblique or perpendicular-long cutting method is considered to be a better cutting type than the perpendicular-short cutting method.