• Title/Summary/Keyword: GP

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A study on corrosion resistance and surface properties of AZ31 alloy according to Ca-GP addition during PEO treatment (PEO 처리시 Ca-GP첨가에 따른 AZ31합금의 내식성 및 표면특성에 관한 연구)

  • Lee, Jun-Su;Park, Je-Shin;Park, Il-Song
    • Journal of Surface Science and Engineering
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    • v.54 no.5
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    • pp.238-247
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    • 2021
  • PEO (plasma electrolytic oxidation) was applied to modify the surface of AZ31 magnesium alloy in this study. The mixed solution of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) was used as the electrolyte, and 0 - 0.05 g/L of Ca-GP (Glycerol Phosphate Calcium salt) was added in the electrolyte as an additive. PEO treatment was conducted at a current density of 30mA/cm2 for 5 minutes using a DC power supply. The surface properties were identified by SEM, XRD and surface roughness analyses, and the corrosion resistance was evaluated by potentiodynamic polarization and immersion tests. In addition, the biocompatibility was evaluated by immersion test in SBF solution. As the concentration of Ca-GP was increased, the surface morphology was denser and more uniform, and the amount of Ca and the thickness of oxide layer increased. Only Mg peak was observed in XRD analysis due to very thin oxide layer. The corrosion resistance of PEO-treated samples increased with the concentration of Ca-GP in comparision with the untreated sample. In particular, the highest corrosion resistance was identified at the group of 0.04g Ca-GP through potentiodynamic polarization and immersion tests in saline solution (0.9 wt.%NaCl). During the immersion in saline solution, pH rapidly increased at the beginning of immersion period due to rapid corrosion, and then increase rate of pH decreased. However, the pH value in the SBF temporarily increased from 7.4 to 8.5 during the day, then decreased due to the inhibition of corrosion with HA(hydroxyapatite) formation.

Micro-computed tomographic evaluation of single-cone obturation with three sealers

  • Sahar Zare;Ivy Shen;Qiang Zhu;Chul Ahn;Carolyn Primus;Takashi Komabayashi
    • Restorative Dentistry and Endodontics
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    • v.46 no.2
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    • pp.25.1-25.12
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    • 2021
  • Objectives: This study used micro-computed tomography (µCT) to compare voids and interfaces in single-cone obturation among AH Plus, EndoSequence BC, and prototype surface pre-reacted glass ionomer (S-PRG) sealers and to determine the percentage of sealer contact at the dentin and gutta-percha (GP) interfaces. Materials and Methods: Fifteen single-rooted human teeth were shaped using ProTaper NEXT size X5 rotary files using 2.5% NaOCl irrigation. Roots were obturated with a single-cone ProTaper NEXT GP point X5 with AH Plus, EndoSequence BC, or prototype S-PRG sealer (n = 5/group). Results: The volumes of GP, sealer, and voids were measured in the region of 0-2, 2-4, 4-6, and 6-8 mm from the apex, using image analysis of sagittal µCT scans. GP volume percentages were: AH Plus (75.5%), EndoSequence BC (87.3%), and prototype S-PRG (94.4%). Sealer volume percentages were less: AH Plus (14.3%), EndoSequence BC (6.8%), and prototype S-PRG (4.6%). Void percentages were AH Plus (10.1%), EndoSequence BC (5.9%), and prototype S-PRG (1.0%). Dentin-sealer contact ratios of AH Plus, EndoSequence BC, and prototype S-PRG groups were 82.4% ± 6.8%, 71.6% ± 25.3%, and 70.2% ± 9.4%, respectively. GP-sealer contact ratios of AH Plus, EndoSequence BC, and prototype S-PRG groups were 65.6% ± 29.1%, 80.7% ± 25.8%, and 87.0% ± 8.6%, respectively. Conclusions: Prototype S-PRG sealer created a low-void obturation, similar to EndoSequence BC sealer with similar dentin-sealer contact (> 70%) and GP-sealer contact (> 80%). Prototype S-PRG sealer presented comparable filling quality to EndoSequence BC sealer.

Assessment of decontamination of gutta-percha cone and the change of surface texture after rapid chemical disinfection (화학소독제 처리 후 가타파차 콘의 멸균 효과 및 표면 성상의 변화 평가)

  • Pang, Nan-Sim;Jung, Il-Young;Yu, Yoon-Jung;Kum, Kee-Yeon
    • Restorative Dentistry and Endodontics
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    • v.31 no.2
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    • pp.133-139
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    • 2006
  • The purposes of this study were firstly to identify the microbial species on gutta-percha (GP) cones exposed at outpatient clinics using polymerase chain reaction, and secondly to evaluate the rapid sterilization effect of two chemical disinfectants at chair side. It also evaluated the alteration of surface texture of GP cones after 5-min soaking into two chemical disinfectants. A total of 100 GP cones from two endodontic departments were randomly selected for microbial detection using PCR assay with universal primer. After inoculation on the sterilized GP cones with the same microorganism identified by PCR assay, they were soaked in two chemical disinfectants: 5% NaOCl and 2% chlorhexidine for 1, 3, 5, and 10 minutes. The sterilization effect was evaluated by turbidity and subculture. The change of surface textures using a scanning electron microscope was also examined after 5 min-soaking in two chemical disinfectants. Results showed that four bacterial species were detected in 17 GP cones, and all the species belonged to the genus Staphylococcus. Two chemical disinfectants were effective in sterilization with just 1 minute soaking. On the SEM picture of NaOCl-soaked GP cone, a cluster of cuboidal crystals was seen on the cone surface. Present data demonstrate that two chemical disinfectants are useful for rapid sterilization of GP cone just before obturation at chair side, while CHX-soaked GP cone has cleaner surface without crystal precipitation than that of NaOCl-treated cone.

Fluoride Release and Recharge Properties of Several Fluoride-Containing Restorative Materials (수종의 불소함유 수복재의 불소 유리 및 재충전)

  • Lee, Dongyun;Kim, Jongsoo;Han, Miran;Shin, Jisun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.47 no.2
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    • pp.196-204
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    • 2020
  • The aim of the study is to compare the fluoride release and recharge properties of glass ionomer cements and 'alkasite'. Specimens of two glass ionomer cements (Fuji IX GP and Riva Self Cure), 'alkasite' restorative material (Cention N) and composite resin (Filtek™ Z350XT) were prepared. The fluoride release of each specimen was measured for 28 days. Thereafter, 1.23% acidulated phosphate fluoride (APF) gel was applied to experimental groups. No treatment was performed on control groups. The fluoride release was measured for additional 7 days to evaluate the fluoride recharge properties of each materials. The fluoride release was highest in Riva Self Cure, followed by Fuji IX GP, Cention N (p < 0.05). Fluoride release of Cention N was measured to be approximately 49% of Fuji IX GP's. After the application of 1.23% APF gel, increases in fluoride release were observed in Riva Self Cure, Fuji IX GP and Cention N (p < 0.05). Fluoride recharge was observed in Cention N as well as in glass ionomer cements. Further studies are required to evaluate the anti-cariogenic properties of Cention N at clinical conditions.

Comparative Evaluation of Drug Use for Outpatients Prescribed by General Practitioner and Specialized Practitioner in ENT Area (이비인후과 영역에서 일반의와 전문의에 의한 외래처방전의 비교 평가)

  • Min, Hyun-Seong;Song, Tae-Beom;Lee, Myung-Koo;Jang, Je-Kwan;Lee, Chong-Kil;Lim, Sung-Cil
    • YAKHAK HOEJI
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    • v.54 no.4
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    • pp.258-269
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    • 2010
  • As people are easy to access the National Health Insurance, medical health service has been increased. It contributed to extend human's average life expectancy and to get better health care. But also increased unnecessary health service or inappropriate drug use. Therefore, DUR (Drug Use Review) is needed to induce appropriate drug use. The purpose of this study is to evaluate outpatient prescriptions by General Practitioner (GP) and Specialized Practitioner, especially indication for ENT referral including common cold which is the frequent indications that have patient see doctor. This study was reviewed retrospectively prescriptions for ENT referral collected at the A pharmacy for ENT Clinic in Cheong-Ju, B pharmacy for GP Clinic in BoEun from Feb 2nd, 2009 to Feb 28th, 2009. Each pharmacy located closed to the each enrolled clinic. The numbers of collected prescriptions were each A pharmacy (n=2501), B pharmacy (n=1343). This study was classified Drug Related Problems (DRPs) those prescriptions had as total 6 groups according to following 6 categories; 1) Unnecessary Drug, 2) Wrong Drug, 3) Low Dose, 4) Overdose, 5) Wrong Instruction, 6) Wrong Combination. In results, Specialized Practitioner's prescriptions had more DRPs than General Practitioner's prescriptions (ENT 155.34% vs GP 130.01%). In detail, Specialized Practitioner's prescriptions had more DRPs in Low Dose (ENT 16.95% vs GP 4.77%), Overdose (ENT 6.72% vs G.P 5.51%), Wrong Instruction (ENT 7.91% vs GP 5.81%), Wrong Combination (ENT 29.31% vs GP 25.09%). These DRPs would be caused from lack of consideration for dosage and drug interaction. General Practitioner's prescriptions had more DRPs in Unnecessary Drug (ENT 70.37% vs GP 78.85%), Wrong drug (ENT 4.12% vs GP 9.98%). These DRPs would be associated with drug selection. This study was assumed that Specialized Practitioner is better prescriber than General Practitioner because Specialized Practitioner complete additional intern and residency training. But, Specialized Practitioner is not always better prescriber than General Practitioner. Furthermore, prescriptions of both Specialized Practitioner and General Practitioner had many problems. In conclusion, It could be cut down the excessive medical expense and expected more efficient medical care by reducing DRPs, thus contributing to the improvement of national health. In order to pharmacist must have good professional ability of pharmacotherapy to help the physician for the drug selection.

Effects of Dietary Garlic Powder on Growth Performance and mRNA Expression of Hepatic HMG-CoA Reductase in Broiler Chickens (육계 사료 내 마늘분말의 첨가급여가 육계 성장과 HMG-CoA Reductase의 mRNA 발현에 미치는 영향)

  • You, Sun-Jong;Ahn, Byoung-Ki;Kang, Chang-Won
    • Journal of Animal Science and Technology
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    • v.51 no.4
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    • pp.307-314
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    • 2009
  • This experiment was conducted to investigate the effects of dietary garlic powder (GP) on growth performance and mRNA expression of hepatic 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase) in broiler chickens. Day-old male chicks (Ross, n=270) were fed diets containing 0% [positive control (PC) with antibiotics or negative control (NC) without antibiotics], 1%, 3% and 5% GP for 6 wks. There were no significant differences in feed intake among the treatments throughout the experimental period. Body weight gains in groups fed dietary GP at 3% and 5% were significantly higher than that of NC group (P<0.05). Feeding GP up to 5% did not exert any adverse effect on weight gain and feed intake. There were no significant differences in the relative weights of liver, spleen, cecum and breast muscle. The content of meat cholesterol in GP containing dietary groups tended to be reduced as compared to NC group. Average infectious bronchitis antibody titers in chicks fed GP containing diets were significantly higher than that of NC group (P<0.05). The mRNA expression of hepatic HMG-CoA reductase was reduced by dietary GP. These results indicate that dietary GP has growth promoting effects and tended to alter cholesterol metabolism in broiler chickens.

Characteristics and Purification of Bacteriocin Produced by Lactobacillus acidophilus GP4A (Lactobacillus acidophilus GP4A가 생산하는 박테리오신의 특성 및 정제)

  • Han, Gyeong-Sik;Joo, Gwan-Seok;Kim, Se-Heon
    • Journal of Dairy Science and Biotechnology
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    • v.17 no.1
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    • pp.1-10
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    • 1999
  • A bacteriocin produced by Lab. acidophilus GP4A isolated from fecal contents of pig was characterized. Lab. acidophilus GP4A produced a heat-stable and pH-resistant bacteriocin, which was hydrolyzed by trypsin and pepsin and active against various microorganisms. Lab. acidophilus GP4A produced bacteriocin at maximum rate when grown in MRS broth(pH 6.5${\sim}$7.5) at$37^{\cric}C$ or $40^{\cric}C$. The bacteriocin produced by Lab. acidophilus GP4A inhibited the growth of Lactobacillus delbrueckii subsp. lactis 4794 in early logarithmic phase. The bacteriocin was purified by ammonium sulfate precipitation and Octyl sepharose CL-4B column chromatography. The purification resulted in a final yield of 21.7% and a 13.6-fold increase in the specific activity.

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Neuroprotective Effects of Herbal Ethanol Extract from Gynostemma pentaphyllum on Dopamine Neurons in Rotenone- and MPTP-induced Animal Model of Parkinson's Disease (Rotenone- 및 MPTP-유도 파킨슨병 동물 모델에서 돌외 에탄올 추출물의 Dopamine 신경세포 보호작용)

  • Suh, Kwang Hoon;Choi, Hyun Sook;Shin, Kun Seong;Zhao, Ting Ting;Kim, Seung Hwan;Hwang, Bang Yeon;Lee, Chong Kil;Lee, Myung Koo
    • YAKHAK HOEJI
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    • v.57 no.2
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    • pp.77-86
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    • 2013
  • The neuroprotective effects of herbal ethanol extract (GP-EX) from Gynostemma pentaphyllum on dopamine neurons in animal model of Parkinson's disease (PD) were investigated. Rats and mice were administered with rotenone (2.5 mg/kg) for 28 days and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg) for 5 days for the PD models, respectively and the animals were simultaneously treated with GP-EX (30 mg/kg, daily). After preparing the PD models, the animals were also administered with L-DOPA (10 mg/kg) for 14 days with or without GP-EX treatment. Treatment with GP-EX (30 mg/kg) inhibited the rotenone- and MPTP-induced neurotoxic effects in dopamine neurons of rats or mice, which was determined by the numbers of tyrosine hydroxylase-immunohistochemical staining survival cells, as well as the levels of dopamine, 3,4-dihydroxyphenylacetic acid and homovanillic acid. GP-EX (30 mg/kg) also showed the protective effects on neurotoxicity which was induced by long-term administration of L-DOPA (10 mg/kg) in rotenone- and MPTP-induced animal model of PD. The used doses of GP-EX (30 mg/kg) did not produce any signs of toxicity, such as weight loss, diarrhea, or vomiting, in rats and mice during the treatment periods. These results suggest that GP-EX has the protective functions against chronic L-DOPA-induced neurotoxic reactions in dopamine neurons of rotenone- and MPTP-induced animal model of PD. Therefore, the natural GP-EX may be beneficial in the prevention of PD progress and L-DOPA-induced neurotoxicity in PD patients.

계란의 등급과 규격 ( I ) - 알의 구조와 일반적 성질 -

  • 오봉국
    • KOREAN POULTRY JOURNAL
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    • v.15 s.168
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    • pp.61-65
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    • 1983
  • 계란 유통구조 개선을 위한 움직임이 이제는 구체화되어가고 있다. 지난 3월 채란업자 대표들이 일본의 계란 생산에서 유통과정과 소비자에까지 전과정을 시찰하고 온데 이어 10월 중에는 농수산부, 축협중앙회, 양계협회 대표로 구성되는 선진국 GP 센타 조사단이 출국할 예정이다. 계란은 무엇이며 어떻게 처리되어야 하나? GP 센타 설치에 앞서 선진국 계란의 등급과 규격에 대하여 알아 본다.

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Quality and Sensory Characteristics of White Bread added with Various Ginseng Products (인삼제품의 첨가에 따른 제빵적성 및 관능평가)

  • Song, Mi-Ran;Lee, Ka-Soon;Lee, Byeong-Chan;Oh, Man-Jin
    • Food Science and Preservation
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    • v.14 no.4
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    • pp.369-377
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    • 2007
  • This study investigated the effect of ginseng products on the baking properties of white breads. Flour was substituted by ginseng products (ginseng at levels 2, 4, 6, and 8%, all w/w, of flour levels). Both ginseng powder (GP) and red ginseng powder (RGP) were used. Similarly, red ginseng extract (RGE) was substituted at levels of 1, 2, 3, and 4% (all w/w) of flour. The physical properties of each dough were assessed using farinograms, extensograms, and amylograms. Water absorption increased as the proportions of ginseng products rose. The dough surface areas and R/E (resistance/extensibility) values decreased, as did peak viscosities, at the proportions of ginseng products increased. The pH values during fermentation decreased as the proportions of ginseng products increased. The fermentation power of dough with GP was lower than that of control, and higher than that of dough with RGP or RGE, but the addition of ginseng products beyond certain levels weakened the gas retention power: The specific loaf volumes of breads with 2% GP were the highest at 5.41 mL/g. In breads with RGE, the specificloaf volume increased from 5.52 mL/g to 5.82 mL/g as RGE levels rose from 0% to 4%. Hardness increased with rising GP and RGP levels in breads with GP and RGP, but decreased with RGE levels in breads with RGE. The moisture contents of breads during storage tended to be higher than control in breads with ginseng products. Lightness increased with addition of GP and decreased upon addition of RGP or RGE, while redness and yellowness increased after addition of any ginseng products. In sensory evaluation tests, the sensory scores for texture, color, mouth feel, and overall acceptability, were high, when any ginseng product (GP, RGP or RGE) was present at 2%. Of these breads, the bread with 2% RGE attained the highest sensory score.