• Title/Summary/Keyword: Confocal microscopy

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EFFECT OF ETCHING TIME ON ENAMEL SURFACE ROUGHNESS: CONFOCAL LASER SCANNING MICROSCOPIC STUDY (공초점 레이저주사현미경을 이용한 산부식 시간에 따른 법랑질 표면 양상에 관한 연구)

  • Kam, Dong-Hoon;Kim, Jung-Wook;Jang, Ki-Taeg;Lee, Sang-Hoon;Kim, Chong-Chul;Hahn, Se-Hyun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.30 no.1
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    • pp.41-46
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    • 2003
  • In order to evaluate the sufficient etching time for successful bonding and also minimizing unnecessary mineral loss, the enamel surface roughness analysis was performed using confocal laser scanning microscopy. Sixty extracted sound human molar teeth were imbedded in the center of acrylic cylinder using self-curing clear resin exposing buccal surface, and then polished with series of SiC paper(220, 500, 800, 1000, 2000, 4000 grit). Each specimen was randomly assigned to six groups(N=10). 37% phosphoric acid was applied to the polished tooth surface for 10, 20, 30, 40, 50, 60 seconds respectively and washed with copious water. After the surface roughness analysis, five roughness parameters(Sa, Sq, Sz, Sdr, Ra) were statistically analysed by ANOVA and Duncan post hoc test. We found that the all five parameters had higher roughness value in 30 seconds etching time, especially parameter Sz showed the lowest value in 10 seconds etching time and the highest value in 30 seconds etching time compared with the other etching times(p<0.05).

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The bactericidal effect of an atmospheric-pressure plasma jet on Porphyromonas gingivalis biofilms on sandblasted and acid-etched titanium discs

  • Lee, Ji-Yoon;Kim, Kyoung-Hwa;Park, Shin-Young;Yoon, Sung-Young;Kim, Gon-Ho;Lee, Yong-Moo;Rhyu, In-Chul;Seol, Yang-Jo
    • Journal of Periodontal and Implant Science
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    • v.49 no.5
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    • pp.319-329
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    • 2019
  • Purpose: Direct application of atmospheric-pressure plasma jets (APPJs) has been established as an effective method of microbial decontamination. This study aimed to investigate the bactericidal effect of direct application of an APPJ using helium gas (He-APPJ) on Porphyromonas gingivalis biofilms on sandblasted and acid-etched (SLA) titanium discs. Methods: On the SLA discs covered by P. gingivalis biofilms, an APPJ with helium (He) as a discharge gas was applied at 3 different time intervals (0, 3, and 5 minutes). To evaluate the effect of the plasma itself, the He gas-only group was used as the control group. The bactericidal effect of the He-APPJ was determined by the number of colony-forming units. Bacterial viability was observed by confocal laser scanning microscopy (CLSM), and bacterial morphology was examined by scanning electron microscopy (SEM). Results: As the plasma treatment time increased, the amount of P. gingivalis decreased, and the difference was statistically significant. In the SEM images, compared to the control group, the bacterial biofilm structure on SLA discs treated by the He-APPJ for more than 3 minutes was destroyed. In addition, the CLSM images showed consistent results. Even in sites distant from the area of direct He-APPJ exposure, decontamination effects were observed in both SEM and CLSM images. Conclusions: He-APPJ application was effective in removing P. gingivalis biofilm on SLA titanium discs in an in vitro experiment.

Fluorescent Silk Fibroin Nanoparticles Prepared Using a Reverse Microemulsion

  • Myung, Seung-Jun;Kim, Hun-Sik;Kim, Yeseul;Chen, Peng;Jin, Hyoung-Joon
    • Macromolecular Research
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    • v.16 no.7
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    • pp.604-608
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    • 2008
  • Color dye-doped silk fibroin nanoparticles were successfully fabricated using a microemulsion method. An aqueous silk fibroin solution was prepared by dissolving cocoons (Bombyx mori) in a concentrated lithium bromide solution followed by dialysis. A color dye solution was also mixed with the aqueous silk fibroin solution. The surfactants used for the microemulsion were then removed by methanol and ethanol, yielding color dye-doped silk fibroin nanoparticles, approximately 167 nm in diameter. The secondary structure of the nanoparticles showed a $\beta$-sheet conformation, as characterized by Fourier transform infrared spectroscopy. The morphology of the nanoparticles was determined by field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy, and their size and size distribution were measured by dynamic light scattering. The color dye-doped silk fibroin nanoparticles were examined by confocal laser scanning microscopy.

Crater Wear Volume Calculation and Analysis (크레이터 마모의 체적계산 및 분석법)

  • Jeong, Jin-Seok;Cho, Hee-Geun;Yoon, Moon-Chul
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.18 no.3
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    • pp.248-254
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    • 2009
  • The worn crater wear geometry of coated tools after machining has been configured by using Confocal Laser Scanning Microscopy(CLSM) and the Wavelet-based filtering technique. The CLSM can be well suited to construct the three-dimensional crater wear on the rake surfaces of coated tips. However, The raw heightness data of HEI(height encoded image) acquired by CLSM must be filtered due to the electronic and imaging noise occurring in constructing the crater image. So the Wavelet-based filtering algorithm is necessary to denoise the shape features in a micro scales so as to realize accurate crater wear topography analysis. The crater wear patterns filtered enable us to predict the crater wear shape in order to study the tool wear evolution. The study shows that the technique by combining the CLSM and Wavelet-based filtering is an excellent one to obtain the geometries of worn tool rake surfaces over a wide range of surface resolution in a micro scale.

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Microbial and Physicochemical Monitoring of Granular Sludge During Start-up of Thermophilic UASB Reactor

  • Ahn, Yeong-Hee;Park, Sung-Hoon
    • Journal of Microbiology and Biotechnology
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    • v.13 no.3
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    • pp.378-384
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    • 2003
  • Mesophilically-grown granular sludge seeded in thermophilic UASB reactor was monitored to better understand the start-up process of the reactor. The reactor was fed with a synthetic wastewater containing glucose. As COD loading rate increased stepwise, methane production rate increased. Maximum values of COD removal efficiency (95%) and methane production rate (5.3 l/day) were achieved by approximately day-80 and remained constant afterward. However, physicochemical and microbial properties of granules kept changing even after day-80. Specific methanogenic activity (SMA) was initially negligible, and increased continuously until day-153 and remained constant afterward, showing the maximum value of $1.51{\pm}0.13\;g\;CH_4-COD/g$ VSS/day. Deteriorated settling ability of granules recovered the initial value by day-98 and was maintained afterward, as determined by sludge volume index. Initially reduced granule size increased until day-126, reaching a plateau of 1.1 mm. Combined use of fluorescence in situ hybridization and confocal laser scanning microscopy (CLSM) allowed to localize families of Methanosaetaceae and Merhanosarcinaceae in granules with time Quantitative analyses of CLSM images of granule sections showed abundance patterns of the methanogens and numerical dominance of Methanosaeta spp. throughout the start-up period. The trend of SMA agreed well with abundance patterns of the methanogens.

Development of DNA Sensor Using Magnetic Iron Oxide Nanoparticle (자성 산화철(iron oxide) 나노입자를 이용한 DNA 센서 개발)

  • Nam, Ki-Chang;Song, Kwang-Soup
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.48 no.6
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    • pp.51-56
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    • 2011
  • The surface of magnetic iron oxide nanoparticles (${\gamma}-Fe_2O_3$) is functionalized ($-NH_2$, -COOH) with bifunctional organic molecules and evaluated using FT-IR (Fourier transform infrared spectroscopy). We immobilize 21-base pair probe DNA and hybridize fluorescence-labeled (Cy5) target DNA onto the functionalized iron oxide nanoparticles. The fluorescence images obtained from a confocal microscopy show that the functionalized iron oxide nanoparticles should detect the hybridization of complementary and noncomplementary DNA.