• Clean Technology
• /
• v.27 no.1
• /
• pp.55-60
• /
• 2021

Antibiotics are compounds broadly used to treat patients with infectious diseases and to enhance productivity in agriculture, fisheries, and livestock industries. However, due to the overuse of antibiotics and their low biodegradability, a substantial amount of antibiotics is leaking into the sewer, subsequently resulting in pollution and the emergence of antibiotic-resistant bacteria. This study explores biodegradable serum albumin's potential as an adsorbent to remove antibiotics from water. Serum albumin is a natural blood protein that transports various metabolites and hormones to all tissues' extravascular spaces. While serum albumin is highly water-soluble, it has intrinsic binding sites which readily accommodate ionic, hydrophilic, or hydrophobic molecules, rendering it a good building block for a nano-adsorbent. To induce coacervation, a desolvating agent, ethanol, was added dropwise into the aqueous albumin solution, resulting in dehydration and liquid-liquid phase separation of albumins into albumin nanoparticles within a size range of 150 ~ 170 nm. The addition of glutaraldehyde as a cross-linker improved the size stability and homogeneity of albumin nanoparticles. Adsorption of amoxicillin antibiotics on albumin nanoparticles was dependent upon glutaraldehyde concentration used in desolvation and pH during adsorption. The maximum adsorption capacity measured by spectrophotometry was found to be 12.4 micrograms of amoxicillin per milligram of albumin nanoparticle. These results demonstrate serum albumin's potential as a building block for fabricating a natural nano-adsorbent to remove antibiotics from water.

• Clean Technology
• /
• v.29 no.1
• /
• pp.10-21
• /
• 2023

Hydrogels that are made of natural polymer-based double networks have excellent biocompatibility, low cytotoxicity, and high water content, assuring that the material has the properties required for a variety of biomedical applications. However, hydrogels also have limitations due to their relatively weak mechanical properties. In this study, hydrogels based on an alginate di-aldehyde (ADA) and gelatin (Gel) double network that is reinforced with additional hydrogen bonds formed between the hydroxyl (-OH) groups of the hyperbranched polymer (HPG) and the functional groups present inside of the hydrogels were successfully synthesized. The enhanced mechanical properties of these synthesized hydrogels were evaluated by varying the amount of HPG added during the hydrogel synthesis from 0 to 25%. In addition, magnetite nanoparticles (Fe₃O₄ NPs) were synthesized within the hydrogels and the structures and the magnetic properties of the hydrogels were also characterized. The hydrogels that contained 15% HPG and Fe₃O₄ NPs exhibited superparamagnetic behaviors with a saturation magnetization value of 3.8 emu g^-1. These particular hydrogels also had strengthened mechanical properties with a maximum compressive stress of 1.1 MPa at a strain of 67.4%. Magnetic hydrogels made with natural polymer-based double networks provide improved mechanical properties and have a significant potential for drug delivery and biomaterial application.

• Polymer(Korea)
• /
• v.38 no.6
• /
• pp.815-819
• /
• 2014

Scaffolds of tissue engineering should be biocompatible and biodegradable for cell attachment, proliferation and differentiation. In the various scaffold fabrication, 3D printing technique can make the three dimensional scaffold with interconnected pores for cell ingrowth. Polycaprolactone (PCL) is biodegradable polyester with a low melting temperature and has been approved by the Food and Drug Administration (FDA). In this study, PCL scaffold was fabricated by 3D bioprinting system and surface modification of PCL scaffold was controlled by NaOH treatment. Morphological change and wetability of NaOH-treated scaffold were observed by SEM and contact angle measurement system. The remnant of PCL treated with NaOH was measured by ATR-FTIR. In vitro study of scaffolds was evaluated with WST-1 and ALP activity assay. NaOH treatment of PCL scaffolds increased surface roughness, hydrophilicity, cell proliferation and osteogenic differentiation. These results indicate that NaOH-treated PCL scaffold made by 3D bioprinting has tissue engineered potential for the development of biocompatible material.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.1 s.129
• /
• pp.63-76
• /
• 2005

Wood-culture is new paradigm which is substituted for the cement culture, and the study of wood-culture should keep pace with not only the study of a engineering science but also a sociological study to form a theory system. The purpose of this study is to suggest the method of sociological approach of the wood culture which have not yet tried at home and abroad; in view of structural-functionalism, systemical-functionalism, conflict theory, social-change theory by analyzing cases in Korea. In view of structural-functionalism, social system consists of cognition system, institution system, life system and technology system. These sub-systems fulfill the function of what-should-be, reasonability, reality and development. In view of systemical-functionalism, according to the acknowledgment and spreading proccess of the wood usefulness, wood culture system consists of the individual system, organizational system and the social system. In view of conflict theory, the society which has the wood culture can be classified into three types. The one is society which the traditional wood culture is declining and the cement culture is spreading. The other one is society which the cement culture is declining and the traditional wood culture is spreading. Another is Finally the society which the two type balance with. In view of social-change theory, the society can be classified into three types. The one is society which the wood culture is proceeding to the cement culture. The other is society which the cement culture is proceeding to the wood culture. Another is society which the wood culture changes itself. Finally, from a view of changing level, the society can be classified into three types: the micro-change, the middle-level-change, and the macro-change. It's need to study wood culture systemically in view of engineering and sociological science. And then it will be possible to make 'wood culture theory system'.

• Korean Journal of Food Science and Technology
• /
• v.51 no.5
• /
• pp.447-451
• /
• 2019

6-gingerol can be converted to 6-shogaol, one of the predominant active compounds found in ginger, via processing such as drying and extraction. Subcritical water extraction is the environmentally friendly method of extraction of bioactive compounds using only purified water as a solvent. This study investigated subcritical water extraction ($190^{\circ}C$, 15 min) of 6-gingerol, and 6-shogaol from dried ginger (Zingiber officinale) including drying conditions such as temperature (room temperature, 60, $80^{\circ}C$, and freeze drying) and time duration for drying (1-4 h). The amount of 6-gingerol was found to be reduced, and that of 6-shogaol was found to be increased depending upon the water content of dried ginger. Upon oven-drying ginger at $60^{\circ}C$ for 2 h, the maximum yields of 6-gingerol ($0.18{\pm}0.02mg/g$ fresh weight), and 6-shogaol ($0.47{\pm}0.02mg/g$ fresh weight) were obtained upon subcritical water extraction.

• Journal of Plant Biotechnology
• /
• v.50
• /
• pp.56-62
• /
• 2023

Transgenic lilies have been obtained using Agrobacterium tumefaciens (AGL1) with the plant scale explants, followed by DL-phosphinothricin (PPT) selection. In this study, scales of lily plants cv. "red flame" were transformed with the pCAMBIA3301 vector containing the gus gene as a reporter and the blpR gene as a selectable marker, as well as a gene of interest showing herbicide tolerance, both driven by the CaMV 35S promoter. Using a 20-minute infection time and a 5-day cultivation period, factors that optimized and demonstrated a high transformation efficiency were achieved. With these conditions, approximately 22-27% efficiency was observed for Agrobacterium-mediated transformation in lilies. After transformation with Agrobacterium, scales of lilies were transferred to MS medium without selective agents for 2 weeks. They were then placed on selection MS medium containing 5 mg/L PPT for a month of further selection and then cultured for another 4-8 weeks with a 4-week subculture regime on the same selection medium. PPT-resistant scales with shoots were successfully rooted and regenerated into plantlets after transferring into hormone-free MS medium. Also, most survived putatively transformed plantlets indicated the presence of the blpR gene by PCR analysis and showed a blue color indicating expression of the gus gene. In conclusion, when 100 scales of lily cv. "red flame" are transformed with Agrobacterium, approximately 22-27 transgenic plantlets can be produced following an optimized protocol. Therefore, this protocol can contribute to the lily breeding program in the future.

• The Journal of Engineering Geology
• /
• v.3 no.3
• /
• pp.253-266
• /
• 1993

GIS technique was applied for ffie work of water supply protection, and GIS rnaps were produced by this technique in Cheong-ju area. They are actual runoff rnap and regional groundwater protection map. The digital database was estabilished for creation of these maps in EGIS(Environmental Geologic information system). A lot of environmental, hydrological and geotedmical data relating to the area were collected from various sources, and used along with the results of the field investigation and laboratorv works in the interpretation of environmental geologic characteristics of the area. These special maps can be applied in the establishment of water supply protection and regional land use planning. For instant, the actaal runoff rnap is very linportant for hydrologic study, and groundwater protection map for susceptibility to groundwater contamination in the area. Actual runoff of the study area was calculated about 148mm using the method of SCS(Soil Consrevation Service) in GIS. The GIS technique was effective in watershed analysis and water balance study.

• Journal of Korean Library and Information Science Society
• /
• v.40 no.3
• /
• pp.225-247
• /
• 2009

The values of a organization generate belief and activate participation of community members. Accordingly, it is necessary to find new core values of the school library in addition to access and assistance which are the library's traditional values. This study analyzed the central keywords in the contents of mission and vision appeared in the International School Library Standards and acquired core values being composed of 5 fields such as education, collaboration, access, cultural awareness and sensitivity, and democratic citizenship. As a result of analyses of missions and visions in America, Australia, UK, and Canada School Library Standards, it seems that life-long learning skills, physical access and social responsibility are common core values. America and UK School Library Standards which were revised recently are underlining technology skills, multiple literacies and integrated information literacy curriculum particularly. Ultimately, these core values will be utilized as the directions and basic materials for the establishment of missions and visions for the school library in Korea.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.1
• /
• pp.89-94
• /
• 2010

Patterning bacteria and cells on substrates has potential applications in molecular biology, antimicrobial drug screening, environmental monitoring and tissue engineering. We developed a technique to deposit two-dimensional array of bacterial cells onto an agar plate by modifying commercially available thermal inkjet printers. The concentration of the bacterial solution in the cartridge was carefully determined to ensure a single cell suspension in a droplet ejected from a nozzle. We measured quantitatively the effects of the bacterial concentration and the agar concentration on patterning performance. Bacterial patterning by inkjet printer is a low-cost and versatile technique which may replace the existing sophisticated methods.

• Polymer(Korea)
• /
• v.34 no.3
• /
• pp.185-190
• /
• 2010

Recently, an electrospinning process, which is one of various nanotechnologies, has been used in fabricating micro/nanosized fibers. The fabricated electrospun micro/nanofibers has been widely applied in biomedical applications, specially in tissue regeneration. In this study, we fabricated highly aligned electrospun biodegradable and biocompatible poly(${\varepsilon}$-caprolactone)(PCL) micro/nanofibers by using a modified electrospinning process supplemented with a complex electric field. From this process, we can attain highly aligned electrospun nanofibers compared to that fabricated with the normal electrospinning process. To observe the feasibility of the highly aligned electrospun mat as a biomedical scaffold, nerve cells(PC-12) was cultured and it was found that the cells those were well oriented to the direction of aligned fibers.