• Fibers and Polymers
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• v.3 no.3
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• pp.91-96
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• 2002

Polyhydroxyamides derivatized with trifluorormethyl ether and trifluoromethyl ester groups were investigated as possible candidates for a new flame retardant polymer. Model compounds for these derivatized polyhydroxyamides were synthesized and their cyclization chemistry was investigated. The model compound study revealed that trifluorornethyl ester group containing model compounds can cyclize on heating, while trifluoromethyl ether group containing model compounds cannot. The non-fluorinated ether and ether derivatives behaved similarly. The trifluoromethyl ester derivatized polyhydroxyamides were synthesized according to the procedures for the model compounds. TGA characterization revealed that the fluorinated polymers have nearly same thermal stability as the underivatized PHA after cyclization.

• Elastomers and Composites
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• v.54 no.4
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• pp.321-329
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• 2019

A series of poly(hyroxyamide)s (PHAs) was prepared by direct polycondensation reaction of 4,4'-(2,3-pyridinedioxy)dibenzoic acid and/or isophthalic acid with 3,3'-dihydroxybenzidine. The yield percentages of the products were high, and the inherent viscosities of the polymer in DMAc solution at 35℃ were 0.31-0.59 dL/g. All PHA polymers were found to be soluble in polar aprotic solvents such as DMAc, DMSO, NMP, and DMF. On the other hand, LiCl was required to dissolve IPHA-1 in aprotic solvents. Poly(benzoxazole)s (PBOs) were partially soluble in conc-H₂SO₄; IPBO-4, -5, and -6 were partially soluble in NMP only when LiCl was added to the solution, and the solution was heated. The PBO polymers showed a maximum weight loss in the temperature range of 654-680℃, and the char yields at 900℃ under nitrogen atmosphere exceeded 63%.

• Elastomers and Composites
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• v.43 no.4
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• pp.271-280
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• 2008

Aromatic polyhydroxyamides (PHAs) having bulky groups and ether linkages in the polymer main chain were synthesized by the low temperature solution polycondensation reaction. FT-IR, $^{1}H-NMR$, DSC, and TGA were used to study the properties of these polymers. The PHAs were converted into polybenzoxazoles (PBOs) by a thermal cyclization reaction, and endothermic peaks were observed in the range of $220{\sim}400^{\circ}C$. The introduction of the ether and bulky groups in the main chain improved the solubility of the PHAs in aprotic solvents such as DMSO and DMF, but the PBOs were nearly insoluble in common solvents. All the PBOs, except for PBO 5 with 2,6-dimethylphenoxy pendant and 2,3-dihydroxyquinoxaline ring, and PBO 6 with 2,6-dimethylphenoxy pendant and 2,3-dihydroxyquinoxaline ring, exhibited $T_g's$ in the range from 149 to $217^{\circ}C$ by DSC. The thermogravimetric analyses indicated that most of the PBOs were thermally stable up to $400^{\circ}C$ in nitrogen. Maximum weight loss temperatures of PHA 5 and PBO 5 with 2,6-dimethylphenoxy pendant and 2,3-dihydroxyquinoxaline ring were $707^{\circ}C$ and $683^{\circ}C$, respectively, which were the hightest temperatures among the corresponding copolymers. The PBOs in nitrogen exhibited relatively high char yields in the range of $63{\sim}70%$ at $900^{\circ}C$.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2005.11a
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• pp.74-75
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• 2005

In order to evaluate dietary brown seaweed and vancomycin on the performance, layers(Isa brown) were fed on basal diet and diets containing 2.0% of brown seaweed or 10ppm vancomycin. Brown seaweed diet significantly increased(p<0.01) nitrogen balance in layer, while excretion of uric acid nitrogen and metabolizable energy utilization were not different among diets. Layer consumed more the brown seaweed diet(p<0.05). Egg production were significantly different by diets but reduced(p<0.0001) with the experimental period passed. Layer fed brown seaweed diet gave thicker shell eggs, higher Haugh unit and higher egg white CuZnSOD activity compared with those in basal diet. Also, Brown seaweed diet increased MnSOD activity in erythrocyte cytosol and peroxidase in plasma, but decreased peroxide level in plasma, and increased proliferation of PBMC stimulated with PHA-P The result indicated that brown seaweed 2.0% diet in layer improved egg quality and performance due to increased protein synthesis which were related to regulation of antioxidant system and immune cell function in blood.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2550-2558
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• 2013

Poly(o-hydroxyamides)(PHAs) copolymers having oligo(oxy ethylene) pendant in the main chain were synthesized by solution polycondensation reaction at low temperature. Copolymer precursors were studied by fourier transform infrared(FT-IR), differential scanning calorimeter(DSC), thermogravimetric analyzer(TGA), universal testing machine(UTM) and limited oxygen index(LOI). The inherent viscosities of the PHAs measured at $35^{\circ}C$ in DMAc or DMAc/LiCl solution were in the range of 0.74~1.42 dL/g. Solubility of the precursors with higher oligo(oxy ethylene) unit was increased, but the PBOs were nearly insoluble in a variety of solvents. The degradation temperature of the copolymer precursors was recorded in the ranges of $408{\sim}664^{\circ}C$ in nitrogen and char yields showed 13~59% values at $900^{\circ}C$. The mechanical properties and flame retardancy of copolymer precursors decreased with higher oligo(oxy ethylene) unit.

• IMMUNE NETWORK
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• v.3 no.2
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• pp.156-163
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• 2003

Background: $\beta$-1,3-glucans are well known to enhance the immune reactions, resulting in antitumor, antibacterial, antiviral, anticoagulatory and wound healing activities. $\beta$-1, 3-glucans have various activities depending on molecular weight, degree of branching, conformation, water-solubility and intermolecular association. However, the $\beta$-1,3-glucan linked backbone structure is essential and $\beta$-D-glucopyranosyl units are required for immuno-potentiating activities. Result: In this study, we tested the immunophamacological activities of soluble $\beta$-1,3-glucans and confirmed the following activities: (1) $IFN-{\gamma}$ production in PBMCs in the presence or the absence of PHA, LPS, or IL-18; (2) induction of various cytokines in the spleen and thymus; (3) adjuvant effect on the antibody production; (4) nitrogen oxide synthesis in macrophages; (5) the cytotoxic and antitumor effects on cell lines and ICR mice. Conclusion: These results strongly suggested that $\beta$-1,3-glucans possessed various immuno-pharmacological activities.

• KSBB Journal
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• v.11 no.5
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• pp.586-592
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• 1996

Poly(3-hydroxybutyric-co-3-hydroxyvaleric) acid(PHB/HV) copolymer synthesis by Pseudomonas sp. HJ from glucose and cosubstrate was investigated. Taxonomic analysis suggested that Pseudomonas sp. HJ was best marched to Pseudomonas picketti having 78.8% similarity. Pseudomonas sp. HJ produced PHB/HV copolymer containing 60.8 mol% HV and 44.9 mol% HV when supplied with hexadecane and propionic acid as a cosubstrate, respectively. The HV composition in PHB/HV copolymer was controlled by varying the concentration of hexadecane and propionic acid. Propionic acid added after 24 hours of incubation was incorporated as the HV monomer in the PHB/HV copolymer up to 49.6 mol%.

• Journal of Microbiology and Biotechnology
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• v.29 no.10
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• pp.1656-1664
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• 2019

Isoprene has the potential to replace some petroleum-based chemicals and can be produced through biological systems using renewable carbon sources. Ralstonia eutropha can produce value-added compounds, including intracellular polyhydroxyalkanoate (PHA) through fatty acid and lipid metabolism. In the present study, we engineered strains of R. eutropha H16 and examined the strains for isoprene production. We optimized codons of all the genes involved in isoprene synthesis by the mevalonate pathway and manipulated the promoter regions using pLac and pJ5 elements. Our results showed that isoprene productivity was higher using the J5 promoter ($1.9{\pm}0.24{\mu}g/l$) than when using the lac promoter ($1.5{\pm}0.2{\mu}g/l$). Additionally, the use of three J5 promoters was more efficient ($3.8{\pm}0.18{\mu}g/l$) for isoprene production than a one-promoter system, and could be scaled up to a 5-L batch-cultivation from a T-flask culture. Although the isoprene yield obtained in our study was insufficient to meet industrial demands, our study, for the first time, shows that R. eutropha can be modified for efficient isoprene production and lays the foundation for further optimization of the fermentation process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.1-6
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• 2002

Synthesis of new active protein was investigated by heat-treatment and fermentation of kidney beans with Bacillus subtilis ATCC 51189. The amount of water-soluble protein in raw kidney bean (raw protein, RP) was greatly reduced by heating (heated protein, HP) and several new amino acids were synthesized by fermentation. The molecular weights of proteins determined by SDS-PAGE were 118 kDa for RP and a new band of 18.0 kDa For protein (fermented protein, FP) in kidney beans heated and fermented with B. subtilis ATCC 51189. Hemagglutinating activities of RP, HP and FP were 128 HU, 4 HU and 32 HU respectively. Both of RP and FP showed anticancer activity against stomach cancer cell line (SNU-1) at 50 $\mu\textrm{g}$g/mL and lymphocyte stimulating activity at 1 $\mu\textrm{g}$/mL, and stimulated PBMC to secrete IFN-${\gamma}$ and IL-12. However, HP did not show any kinds of activities. Taken together, these results suggested that lectin in kidney beans was destroyed by heating, hut new active lectin-like Protein was derived by fermentation with B. subtilis ATCC 51189.