• IMMUNE NETWORK
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• v.13 no.1
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• pp.30-33
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• 2013

Previously we showed that biodegradable nanoparticles containing poly-IC or CpG oligodeoxynucleotide (ODN) together with ovalbumin (OVA) were efficient at inducing MHC-restricted presentation of OVA peptides in dendritic cells. The CTL-inducing activities of the nanoparticles were examined in the present study. Nanoparticles containing poly-IC or CpG ODN together with OVA were prepared using biodegradable polymer poly(D,L-lactic acid-co-glycolic acid), and then were opsonized with mouse IgG. The nanoparticles were injected into the tail vein of mice, and 7 days later the OVA-specific CTL activities were measured using an in vivo CTL assay. Immunization of mice with the nanoparticles containing poly-IC or CpG ODN together with OVA elicited potent OVA-specific CTL activity compared to those containing OVA only. In accordance with these results, nanoparticles containing poly-IC or CpG ODN together with OVA exerted potent antitumor activity in mice that were subcutaneously implanted with EG7.OVA tumor cells. These results show that encapsulation of poly-IC or CpG ODN together with antigen in biodegradable nanoparticles is an effective approach for the induction of potent antigen-specific CTL responses in vivo.

• KSBB Journal
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• v.26 no.5
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• pp.443-452
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• 2011

In this study, inorganic flocculant with biodegradable polymer flocculant was usedfor microalgae harvest. The aim of this study was to optimize the concentration of inorganic flocculant, the concentration of biodegradable polymer flocculant and reaction volume for decreasing the amounts of flocculant and obtaining the suitable pH range for seawater by response surface methodology. The flocculation of three marine microalgae, Chlorella ellipsoidea, Dunaliella bardawil, and Dunaliella tertiolecta, using inorganic flocculants and biodegradable polymer flocculants was investigated. The results indicated that the optimal flocculant quantity showed 0.1 g/L of ferric chloride, 7.5 g/L of chitosan on Chlorella ellipsoidea. In the case of Dunaliella bardawil, the optimal flocculant quantity showed amount of ferric sulfate more than 0.12 g/L and chitosan more than 0.75 g/L. In the case of Dunaliella tertiolecta, the optimal flocculant quantity showed 1.0 g/L of sodium aluminate, 0.75 g/L of chitosan.

• Macromolecular Research
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• v.16 no.4
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• pp.303-307
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• 2008

A series of biodegradable polymeric scaffolds was prepared by using a combination of natural (collagen) and synthetic (poly(caprolactone)) (PCL) polymers in various compositions. These scaffolds were soft, spongy, porous and transparent in nature and were characterized by thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. The entrapment efficiency and drug release activity of the scaffolds were analyzed using penicillin and tetracycline as antimicrobial drugs. The drug release activity of the scaffolds with various combinations of collagen and PCL were studied by measuring the optical density in a spectrophotometer at the following time intervals: 1,4, 24, 48 and 60 h. These scaffolds showed better and continuous drug release for up to 60 h. Even after such a long duration, a portion of the drug remained entrapped in the scaffolds, indicating that they can be utilized for wound healing applications.

• Polymer(Korea)
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• v.35 no.6
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• pp.580-585
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• 2011

This article aims to enhance the biodegradability and environment-friendliness of petroleum based biodegradable poly(butylene adipate-co-succinate-co-terephthalate)(PBAST) by blending chemically modified thermoplastic starch(CMPS). CMPS is a kind of bio-based biodegradable resin which is manufactured by reacting starch with maleic anhydride(MA) in the presence of a plasticizer and a free radical initiator. The characteristic properties of PBAST/CMPS blends were investigated by observing their morphology, thermal, mechanical properties, and biodegradability. The good interfacial adhesion between the phases examined by SEM revealed that PBAST/CMPS blends were compatible blends. The tensile strength and elongation decreased with increasing CMPS content, while modulus increased. The biodegradability of the blends was much higher than that of pristine PBAST and increased with increasing CMPS contents.

• Macromolecular Research
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• v.16 no.3
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• pp.231-237
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• 2008

Biodegradable poly($\varepsilon$-caprolactone-co-L-lactide)-b-poly(ethylene glycol) (PCLA-b-PEG) copolymers were synthesized via solution polymerization by varying the feed composition of $\varepsilon$-caprolactone ($\varepsilon$-CL) and L-lactide (LLA) ($\varepsilon$-CL: LLA= 10:0, 7:3, 5:5, 3:7, 0: 10). The feed ratio based on weight is in accordance with the copolymer composition except for the case of $\varepsilon$-CL: LLA=3:7 (C3L7), which was verified by $^1H$-NMR. Two different approaches were used for the exceptional case, which is an extension of the reaction time or the sequential introduction of the monomer. A copolymer composition of $\varepsilon$-CL: LLA=3:7 could be obtained in either case. The chemical microstructure of PCLA-b-PEG was determined using the $^{13}C$-NMR spectra and the effect of the sequential structure on the thermal properties and crystallinity were examined. Despite the same composition ratio of the copolymer, the microstructure can differ according to the reaction conditions.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.1
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• pp.35-45
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• 2017

In order to improve the anaerobic digestion efficiency of the sewage sludge, the methane potential of the hydrolysate generated from the hydro-thermal reaction at 170, 180, 190, 200, 210, $220^{\circ}C$ was analyzed and the constitutional characteristics of the organic materials were estimated by dividing organic materials of hydro-thermal hydrolysate into easily biodegradable, decomposition resistant, and non-biodegradable organic materials applying the parallel first order kinetics model. The ultimate methane potential of sewage sludge hydro-thermal hydrolysate increased to 0.39, 0.39, 0.40, 0.44, 0.45, and $0.46Nm^3/kg-VS_{added}$ as hydro-thermal reaction temperature increased from 170, 180, 190, 200, 210, $220^{\circ}C$. It has been shown that the organic matter of sewage sludge is solubilized to increase the content of biodegradable organic material($VS_B$). The easily degradable organic matter($VS_e$) content was highest at hydro-thermal reaction temperature of 200 and $210^{\circ}C$, and optimum hydro-thermal reaction temperature for organic matter solubilization of sewage sludge was in the range of $200{\sim}210^{\circ}C$. In addition, the amount of biodegradable organic material($VS_B$) and easily biodegradable organic matter ($VS_e$) in the hydrolysate of sewage sludge was the highest at hydro-thermal reaction temperature of $200^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.73-78
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• 2017

This study was conducted to elucidate the effects of mulching materials on root growth characteristics and weed occurrence of Platycodon grandiflorum transplants (3 years old) in organic farming. After transplanting, roots were mulched with one of three mulching materials (biodegradable film, sawdust, or rice husks) or a control (no mulching). The average root diameter of all mulching groups was 28.1 mm, which was 5.1 mm thicker than the no-mulching treatment. Roots with the biodegradable film treatment were the thickest at 30.9 mm. Root length was the shortest, 22.0 cm, with rice husk mulching. The number of rootlets was the highest with film mulching (36.0 rootlets/root) and the lowest with no mulching. For root fresh weight, which directly affects yield, the average of treated and untreated roots was 100 and 56 g/root, respectively. The highest fresh weight was in the biodegradable film plot (130 g/root). The mulching treatment groups showed a weed inhibition effect compared with the no-mulching treatment. The dominant weeds with the no-mulching treatment were Setaria viridis and Digitaria ciliaris, and that with the mulching treatment was Setaria viridis. Average annual weed occurrence across all treatments was 72%. Weed occurrence was the highest with the no-mulching treatment ($125weeds/m^2$), and there were no weeds with the biodegradable film treatment.

• Polymer(Korea)
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• v.33 no.5
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• pp.469-476
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• 2009

In this study, biodegradable superporous hydrogels(SPHs) with fast swelling and superabsorbent properties were prepared using biodegradable crosslinkers and their physicochemical properties were characterized. A biodegradable crosslinker (PLA-PEG-PLA DA) was synthesized by a ring opening polymerization of D,L-lactide (LA) using hydrophilic poly(ethylene glycol) as a macroinitiator, followed by diacrylation of the end groups for the introduction of polymerizable vinyl groups. Various kinds of hydrogels with different chemical compositions were prepared and characterized in terms of swelling ratio, swelling kinetics, and biodegradation properties. The synthetic results were confirmed by $^1H$-NMR, FT-IR and GPC measurements, and the porous structures of the prepared SPHs and their porosities were identified by a scanning electron microscope and mercury porosimetry, respectively. The physicochemical properties of SPHs could be controlled by varying their chemical compositions and their cytotoxicity were found to be very low by MTT assay.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.3
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• pp.207-217
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• 2010

The purpose of this study was to evaluate the effects of the stress distribution and displacement in mandible according to treatment modalities of mandibular angle fractures, using a three dimensional finite element analysis. A mechanical model of an edentulous mandible was generated from 3D scan. A 100-N axial load and four masticatory muscular supporting system were applied to this model. According to the number, location and materials of titanium and biodegradable polymer plates, the experimental groups were divided into five types. Type I had a single titanium plate in the superior border of mandibular angle, type II had two titanium plates in the superior tension border and in the inferior compression border of mandibular angle, type III had a single titanium plate in the ventral area of mandibular angle, type IV had a single biodegradable polymer plate in the superior border of mandibular angle, type V had a single biodegradable polymer plate in the ventral area of mandibular angle. The results obtained from this study were follows: 1. Stress was concentrated on the condylar neck of the fractured side except Type III. 2. The values of von-Mises stress of the screws were the highest in the just-posterior screw of the fracture line, and in the just-anterior screw of Type III. 3. The displacement of mandible in Type III was 0.04 mm, and in Type I, II, IV, and V were 0.10 mm. 4. The plates were the most stable in the ventral area of mandibular angle (Type III, V). In conclusion, the ventral area of mandibular angle is the most stable location in the fixation of mandibular angle fractures, and the just- posterior and/or the just-anterior screws of the fracture line must be longer than the other, and surgeons have to fix accurately these screws, and the biodegradable polymer plate also was suitable for the treatment of mandible angle fracture.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1343-1362
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• 2015

As a result of analysis based on the observed data for BOD, COD and TOC in order to manage non-biodegradable organics in the Geumho River, COD/BOD ratio was analyzed as the occupying predominance proportion. In this study, the classification(changes in water quality measurement : increase, equal, decrease) and measurement of BOD and COD were analyzed for trends over the past 10 years from 2005 to 2014 in the Geumho River. The Geumho River is expected to need non-biodegradable organics management because BOD was found to be reduced 61.1% and COD was found to be increased 50%. As a result of the analysis of land use, the Geumho-A is a unit watershed area of $921.13km^2$, which is the most common area that is occupied by forests. The Geumho-B is a unit watershed area of $436.8km^2$, which is the area that is highest occupied by agriculture and grass of 24.84%. The Geumho-C is a unit watershed area of $704.56km^2$ accounted for 40.29% of the entire watershed, which is the area that is occupied by urban of 15.12%. Load of non-biodegradable organics, which is not easy biodegradable according to the discharge, appeared to be increased because flow coefficient of COD and TOC at the Geumho-B were estimated larger than 1 value. The management of non-point sources of agricultural land is required because the Geumho-B watershed area occupied by the high proportion of agriculture and field. In this segment it showed to increase the organics that biodegradation is difficult because the ratio of BOD and TOC was decreased rapidly from GR7 to GR8. Thus, countermeasures will be required for this.