• Journal of Veterinary Clinics
• /
• v.18 no.3
• /
• pp.201-205
• /
• 2001

For evaluating the effect of triple therapy on eradication of gastric Helicobacter species infection in dogs, 7 dogs that had naturally acquired Helicobacter spp. infections were administered amoxicillin, metronidazole and omeparazole orally for 14 days. Changes of infection state were determined by urease test for gastric biopsies and Helicobacter specific PCR analysis for gastric biopsies and fecal samples at 7, 14 days after triple therapy and 30 days after cessation of triple therapy. Although negative results for urease test were obtained 6 of 7 dogs at 14 days after starting triple therapy, PCR analysis for gastric biopsies and fecal samples showed negative results in 3 and 4 dogs respectively. At 30 days after cessation of triple therapy, all tests showed negative results in 3 dogs. Based on these results, diagnostic tests for detercting Helicobacter spp. infection are recommended in dogs having chronic gastritis sign (usually intermittent vomiting) and triple therapy described in this study can be applied for eradicating the organism if the animals were proved to be infected.

• Applied Chemistry for Engineering
• /
• v.16 no.5
• /
• pp.684-688
• /
• 2005

Aniline was polymerized in various protonic acid (HF, HC1, HBr, HI, $H_2SO_4$) aqueous solutions with different acidity. During the reaction, the dimer formation and the reaction rate were examined as functions of acidity (pH) and the size of counter ions. Open-circuit potential measurements were carried out to investigate the effect of protonic acid on the reaction rate. The results showed that polymerization rate in HF aqueous solution was very slow and polymerization did not occur in HI aqueous solution. These results were explained in terms of acidity and power of oxidation. The ratio of formation of dimers varied with the kind of protonic acid, and the results were explained with the nucleophilicity, solvation effect, and mobility of counter ions.

• Polymer(Korea)
• /
• v.34 no.2
• /
• pp.150-153
• /
• 2010

In this research, biomolecule-immobilized multi-walled carbon nanotubes (MWCNTs) were prepared by using radiation-induced graft polymerization. For the immobilization of biomolecules, the surface of MWNCTs was functionalized by radiation-induced graft polymerization of acrylic acid. Based on the results of TGA and Raman spectroscopy it was found that acrylic acid was effectively graft-polymerized on the MWCNTs. Biomolecules such as DNA and proteins were immobilized onto the resultant poly(acrylic acid)-grafted MWCNTs. The results of the X-ray photoelectron spectroscopy and fluorescence microscopy confirmed that the biomoelcules were successfully immobilized on the poly(acrylic acid)-grafted MWCNTs.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.21 no.2
• /
• pp.97-104
• /
• 1988

Condensed phosphates have been used in various meat products to enhance the water holding capacity, to improve texture and to prevent the development of off flavors and off odors. This study was intended to observe the effects of poly - and pyrophosphate on the growth of sanitary indicative bacteria and food poisoning bacteria. The bacteriostatic effect of poly - and pyrophosphates against Gram positive bacteria was much stronger than that of against Gram negative organisms. The effective inhibitory concentration of sodium polyphosphate on the growth of bacteria was varied by species such as $0.3\%$ to Staphylococcus aureus, $0.9\%$ to Salmonella, and more than $1.0\%$ to Escherichia coli in nutrient broth. When Staphylococcus aureus suspension was treated with $0.5\%$ sodium polyphosphate at $35^{\circ}C$ for 1 hour, the release of UV-absorbing substances from the organism was confirmed. However no significant effect was observed in Escherichia coli under the similar condition. When alaska pollack fillets were dipped in $ 3.5\%$ sodium polyphospahate at $2^{\circ}C$ for 1 min. prior to freezing, the viable cell count and coliform MPN's of the frozen product were decreased with the range of 30 to $50\%$ in comparison with those of control.

• Korean Chemical Engineering Research
• /
• v.50 no.6
• /
• pp.1076-1081
• /
• 2012

For the purpose of development of the latex suitable for latex modified concrete, experimental researches on the preparation of carboxylated styrene butadiene latex by the method of the two-step emulsion polymerization and application to concrete were performed. Sodium dodecylbenzene sulfonate and sodium salt of lauryl sulfonate were selected as anionic emulsifiers, and nonylphenoxy poly(ethyleneoxy) ethanols (n=10, 20, 40) as latex stabilizer. Potassium persulfate and sodium bisulfite were used as redox initiator, besides $Na_2HPO_4$ and $K_2CO_3$ as electrolytes. Polymerization recipe of latex suitable for latex modified concrete were suggested from the experimental researches on the effects of anionic emulsifiers and their concentration on the polymerization stability, and the effect of electrolytes concentration on the particle size of latex. Physical properties, such as slump, air contents, compressive and flexural strength, of latex prepared by suggested polymerization recipe were examined. The experimental results showed that latex modified concrete satisfied the quality standards in slump and air contents. Furthermore, it was turned out that the compressive and the flexural strength of latex modified concrete with 28 days curing time showed appreciably improvements.

• Elastomers and Composites
• /
• v.48 no.4
• /
• pp.294-299
• /
• 2013

Solution polymerization was conducted with water-soluble methacrylic acid (MAA) as a monomer and potassium persulfate (KPS) as an initiator at a selected temperature between $70^{\circ}C$ and $90^{\circ}C$. When the ratio between MAA and water was reduced or initiator concentration increased, molecular weights decreased. Molecular weights of poly(methacrylic acid) (PMAA) showed nearly no dependence on reaction temperature. The Weissenberg effect was observed in most polymerization reactions, while its effect weakened at $90^{\circ}C$. The polydispersity index was less than 1.5 in most of the reactions. An increase in the stirring speed produced PMAAs with increasing molecular weights. When the stirring speed reached 800 rpm, we retrieved a monodisperse PMAA with both the number and weight average molecular weights of 791,000 g/mol. The glass transition temperature was found to be $162^{\circ}C$.

• Polymer(Korea)
• /
• v.36 no.1
• /
• pp.65-70
• /
• 2012

Glycidyl methacrylate (GMA) was used to introduce epoxy groups on the surface of polypropylene (PP) plate, used as a substrate, through plasma-induced graft copolymerization. Emulsion polymerization was applied for graft copolymerization of GMA and was compared with conventional solution polymerization to confirm its effect. Plasma treatment conditions under one atmospheric pressure were fixed as follows; the RF power of 200 W, the treatment time of 30 sec, the Ar gas flow rate of 6 LPM, and the exposure time of treated PP samples in air of 5 min. For graft-copolymerization, GMA concentration, reaction temperature, and reaction time was optimized to maximize the grafting degree of GMA. The maximum grafting degree of GMA was obtained at the condition of 12%-GMA concentration, $90^{\circ}C$ reaction temperature, and 5 hr-reaction time. Analysis results supported that the emulsion polymerization was more effective than the solution polymerization for grafting more GMAs on the surface of PP plate under the same reaction conditions.

• Korean Journal of Food Science and Technology
• /
• v.18 no.2
• /
• pp.149-152
• /
• 1986

The effects of polyphosphates (STP, TSPP, SAPP and SHMP) and heart on phyrsicochemical properties of a restructured pork product were studied. Among phosphates studied, no significant differences were found in TBA value and WHC while STP and TSPP showed a significantly better effect on the reduction of cooking loss than SAPP and SHMP. When the products with beef heart (5%, 10%, and 15%) were compared with beef organoleptically, texture and color of the products showed no difference from those of beef regardless of levels of heart. Juiciness was better and cooking loss was lower in the products with heart than in beef. When pork heart was added, cooking loss and TBA value were not significantly different among products with different levels of heart (5%,7.5% and 10%). Color and juiciness were improved significantly with 7.5%, and 10% levels compared to 5% level. The measurements by a color difference meter showed that the improvement of color was mainly due to the increase in redness of tilt product.

• Restorative Dentistry and Endodontics
• /
• v.34 no.2
• /
• pp.145-153
• /
• 2009

The purpose of this study was to evaluate the effect of instrument compliance on the polymerization shrinkage stress measurements of dental composites. The contraction strain and stress of composites during light curing were measured by a custom made stress-strain analyzer, which consisted of a displacement sensor, a cantilever load cell and a negative feedback mechanism. The instrument can measure the polymerization stress by two modes: with compliance mode in which the instrument compliance is allowed, or without compliance mode in which the instrument compliance is not allowed. A flowable (Filtek Flow: FF) and two universal hybrid (Z100: Z1 and Z250: Z2) composites were studied. A silane treated metal rod with a diameter of 3.0 mm was fixed at free end of the load cell, and other metal rod was fixed on the base plate. Composite of 1.0 mm thickness was placed between the two rods and light cured. The axial shrinkage strain and stress of the composite were recorded for 10 minutes during polymerization. and the tensile modulus of the materials was also determined with the instrument. The statistical analysis was conducted by ANOVA. paired t-test and Tukey's test (${\alpha}<0.05$). There were significant differences between the two measurement modes and among materials. With compliance mode, the contraction stress of FF was the highest: 3.11 (0.13). followed by Z1: 2.91 (0.10) and Z2: 1.94 (0.09) MPa. When the instrument compliance is not allowed, the contraction stress of Z1 was the highest: 17.08 (0.89), followed by FF: 10.11 (0.29) and Z2: 9.46 (1.63) MPa. The tensile modulus for Z1, Z2 and FF was 2.31 (0.18), 2.05 (0.20), 1.41 (0.11) GPa, respectively. With compliance mode. the measured stress correlated with the axial shrinkage strain of composite: while without compliance the elastic modulus of materials played a significant role in the stress measurement.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2692-2695
• /
• 2008

Polydiacetylene (PDA) is chemosensor materials that exhibit non-fluorescent-to-fluorescent transition as well as blue-to-red visible color change upon chemical or thermal stress. They have been studied in forms of film or microarray chip, so far. In this paper, we provide a novel technique to fabricate continuous micro-fiber PDA sensor using in-situ laser-polymerization technique and 3-D hydrodynamic focusing on a microfluidic chip. The flow of a monomer solution with diacetylene (DA) monomer is focused by a sheath flow on a 3-D microfluidic chip. The focused flow is exposed to 365 nm UV laser beam for in-situ polymerization which generates a continuous fiber containing DA monomers. Then, the fiber is exposed to 254 nm UV light to polymerize DA monomers to PDA. Preliminary results indicate that the fiber size can be controlled by the flow rates of the monomer solution and sheath flows and that a PDA sensor fiber successively responds to chemical and thermal stress.