• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.3
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• pp.204-211
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• 2017

In dentistry, elevator instruments are used to luxate teeth, and this technique imparts forces to tooth particles that sever the periodontal ligament around tooth roots inside the socket and expand alveolar bone around tooth particles. These effects can result in extraction of the tooth particles or facilitate systematic forceps extraction of the tooth particles. This article presents basic oral surgery techniques for applying elevators to luxate teeth. Determination of the optimal luxation technique requires understanding of the functions of the straight elevator and the Cryer elevator, the concept of purchase points, how the design elements of elevator working ends and tips influence the functionality of an elevator, application of forces to tooth particles, sectioning teeth at furcations, and bone removal to facilitate luxation. The effectiveness of tooth particle luxation is influenced by elevator tip shape and size, the magnitude and the vectors of forces applied to the tooth particle by the tip, and sectioning and bone removal within the operating field. Controlled extraction procedures are facilitated by a dental operating microscope or the magnification of binocular surgical loupes telescopes, combined with co-axial illumination.

• Journal of Periodontal and Implant Science
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• v.46 no.5
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• pp.291-302
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• 2016

Purpose: The aim of the present study was to evaluate the effectiveness of using a mineralized bone cortical allograft (MBCA), with or without a resorbable collagenous membrane derived from bovine pericardium, on alveolar bone remodeling after immediate implant placement in a dog model. Methods: Six mongrel dogs were included. The test and control sites were randomly selected. Four biradicular premolars were extracted from the mandible. In control sites, implants without an allograft or membrane were placed immediately in the fresh extraction sockets. In the test sites, an MBCA was placed to fill the gap between the bone socket wall and implant, with or without a resorbable collagenous membrane. Specimens were collected after 1 and 3 months. The amount of residual particles and new bone quality were evaluated by histomorphometry. Results: Few residual graft particles were observed to be closely embedded in the new bone without any contact with the implant surface. The allograft combined with a resorbable collagen membrane limited the resorption of the buccal wall in height and width. The histological quality of the new bone was equivalent to that of the original bone. The MBCA improved the quality of new bone formation, with few residual particles observed at 3 months. Conclusions: The preliminary results of this animal study indicate a real benefit in obtaining new bone as well as in enhancing osseointegration due to the high resorbability of cortical allograft particles, in comparison to the results of xenografts or other biomaterials (mineralized or demineralized cancellous allografts) that have been presented in the literature. Furthermore, the use of an MBCA combined with a collagen membrane in extraction and immediate implant placement limited the extent of post-extraction resorption.

• Journal of the Korean GEO-environmental Society
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• v.14 no.11
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• pp.25-31
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• 2013

Civil and military firing ranges are usually contaminated with heavy metals such as lead and copper and remediation is required. Acid washing and extraction are common remediation methods. Lead contaminated firing range soil samples were collected and a preliminary study was conducted to evaluate the characteristics of the contamination and the contribution of high specific gravity particles. Ethylenediamine tetra acetic acid(EDTA) extraction was applied for the removal of heavy metal but the extraction was not feasible for the firing range soil. Even after the repeated EDTA extraction, the contamination were still over the Korean environmental standard indicating that soil particles highly contaminated with heavy metal which release the heavy metal ion even after the repeated extraction. Some colored and higher specific gravity particles were separated from the soil samples and analyzed. The colored particles have specific gravity of 2.5-6.6. The saturation ratio of Pb and EDTA was 4.9-32%. After removal of these colored particles, the sandy soil showed moderate contamination which can be treated with soil washing. This was proved with the five-level sequential extraction and TCLP tests.

• The Korean Journal of Food And Nutrition
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• v.4 no.1
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• pp.61-68
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• 1991

In order to study the extraction mechanism of barley tea, some factors affecting extraction and physical properties of roasted barley and extract were examined. The main results of this study are as follows : 1. The roasted barley particles used as the raw materials were amorphous. Under the extraction condition used the average swelling ratio of the particles and imbibed volume were 1. 3g and 1.65ml/g respectively. The maximum soluble solid content in the roasted barley was 67.07%. 2. The concentrations of the barley extracts were determined by measuring their optical densitis at 420nm and the relationship between the concentration(C) and optical density(O. D.) was expressed as : C=6, 178XO. D. As shown in the following relationship, the viscosities(u: Ns/m2) of barley extracts were Influenced by concentration(C : kg/m3) and temperature(T : C). $\mu$=5.6731$\times$$10^{-4}e^{2.7}^{\times10^{{-3}\times{C}}$$\mu$=3.577$\times$$10^{-3}e^{{-3.02}\times{10^{-2}\times{T}}$

• Economic and Environmental Geology
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• v.32 no.1
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• pp.53-62
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• 1999

The possibility of heavy metal pollution by contaminated roadside soils was studied under controlled conditions. The soil samples from roadside and those from a retention pond consisting of settling particles were characterized by the XRD analyses and the sequential extraction experiments. Characterization by sequential extraction, for roadside soil indicates elevate total concentrations of heavy metals. The leaching behavior of the samples under different pH and time conditions were also studied. Differences between both types of samples result mainly from the buffering effect of carbonates, present in roadside soils and lacking from settling particles. Acid leaching of the settling particles is equivalent to the sum of FI+FII+FIII, while the amounts leached from roadside soil are lower probably from kinetic reasons. The buffering effects of carbonates were found to greatly delay the onset of the leaching reactions and the extent of dissolution in most metals except for Ca and Mn. The study of leaching kinetics at pH of 6.5 and 5 showed that Cd and Zn reached the maximum possible concentration within 3 days, while Pb did not show any sign of dissolution at both ph values. The absolute amounts of dissolved Cd and Zn increased by 7 to 9 times by decreasing the pH from 6.5 to 5, indicating slightly acidified rain may result in significant metal dissolution. As deduced from both sequential extraction and leaching experiments, the relative mobility of heavy metals is found to be : Mn=Cd>Zn>>Pb>Fe, in spite of large differences in heavy metal contents and localizations.

• Polymer(Korea)
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• v.36 no.1
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• pp.1-8
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• 2012

In this study, we employed hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta}$-CD) as an excipient to produce poly(lactic-$co$-glycolic acid) (PLGA) fine particles by a supercritical fluid process, called aerosol solvent extraction system (ASES), and investigated the effect of HP-${\beta}$-CD content on the morphology of the particles. The influence of HP-${\beta}$-CD on the drug release characteristics of paclitaxel-loaded PLGA particles was also evaluated. Fine particles were obtained when the HP-${\beta}$-CD content in PLGA/HP-${\beta}$-CD mixtures was greater than 40% and 30%, respectively, for PLGA(75:25) and PLGA(50:50), whereas a film-like precipitate was obtained for lower HP-${\beta}$-CD content. The release rate for paclitaxel loaded PLGA(75:25)/HP-${\beta}$-CD particles was found to increase with HP-${\beta}$-CD content.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.5
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• pp.430-435
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• 2006

Purpose : The aim of this study was to investigate healed bovine bone particles ($Bio-Oss^{(R)}$) and absorbable collagen sponge ($CollaPlug^{(R)}$) applied extraction socket site at 4-6 months' post-extraction. Material and methods : From August, 2004 to October, 2005, 17 sockets in 5 adult patients were selected out of the patients whose received ridge preservation using bovine bone particles and absorbable collagen sponges at Dept. of oral and maxillofacial surgery in Samsung Medical Center. There were 5 male patients, ages 30 to 58 years. Immediate postoperation and 4-6 months after operation study models were compared to evaluate the ridge dimension by measuring vertical height and horizontal width of alveolar ridge. Results : The measurements at 4-6 months revealed, in the ridge dimension, a loss of vertical height of 0.91${\pm}$0.40mm and horizontal width of 1.25${\pm}$0.58mm. There was no adverse reaction. Conclusion : This study suggests that treatment of extraction sockets with graft materials and collagen sponges is valuable in preserving alveolar bone in extraction sockets and preventing alveolar ridges defects.

• Journal of Sensor Science and Technology
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• v.27 no.4
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• pp.237-241
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• 2018

The real-time enrichment and detection of pathogens are serious issues and rapidly evolving field of research because of the ability of these pathogens to cause infectious diseases. In general, bacterial detection is accomplished by conventional colony counting or by polymerase chain reaction (PCR) after DNA extraction. As colony counting requires considerable time to cultivate, PCR is an attractive method for rapid detection. A small number of pathogens can cause diseases. Hence, a pretreatment process, such as enrichment is essential for detecting bacteria in an actual environment. Thus, in this study, we developed a microfluidic chip capable of performing rapid enrichment of bacteria and the extraction of their genes. A lectin, i.e., Concanavalin A (ConA), which shows binding affinity to the surface of most bacteria, was coated on the surface of magnetic particles to nonspecifically capture bacteria. It was subsequently concentrated through magnetic forces in a microfluidic channel. To lyse the captured bacteria, magnetic particles were irradiated by a wavelength of 532nm. The photo-thermal effect on the particles was sufficient for extracting DNA, which was consequently utilized for the identification of bacteria. Our device will help monitor the existence of bacteria in various environmental situations such as water, air, and soil.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1236-1245
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• 2004

In this study, an optical imaging method was developed for the measurements of the sizes and velocities of droplets in sprays. Double-exposure single-frame spray images were captured by the imaging system. An image processing program was developed for the measurements of the sizes and positions of individual particles including separation of the overlapped particles and particle tracking and pairing at two time instants. To recognize and separate overlapping particles, the morphological method based on watershed segmentation as well as separation using the perimeter and convex hull of image was used consecutively. Better results in separation were obtained by utilization of both methods especially for the multiple or heavily-overlapped particles. The match probability method was adopted for particle tracking and pairing after identifying the positions of individual particles and it produced good matching results even for large particles like droplets in sprays. Therefore, the developed optical imaging method could provide a reliable way of analyzing the motion and size distribution of droplets produced by various sprays and atomization devices.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.409-416
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• 1999

Microwave extraction system equipped with closed vessels was applied to confirm its capability of extracting ginseng solubles including saponin, which was monitored to optimize extraction con ditions by response surface methodology. Total yield increased with the decrease in particles size and more extraction steps. Soluble components were completely extracted by operating the system within 6 min per one step, which should be repeated by 3 or 4 times. Optimized conditions for maxi mum extraction of response variables(total yield, crude saponin) were 40~50% of ethanol concentration, about 140oC of extraction temperature, and within 6 min of the extraction time. The extraction effi ciency of total yield was dependent on the decrease of ethanol concentration, while crude saponin content was favored on the higher degree of ethanol concentration. According to the temperature guideline, below 90oC of extraction temperature, the optimal ranges of extraction conditions were predicted as 30~50% of ethanol concentration and 2.5~6.5 min of extraction time. Estimated values of total yield and crude saponin were in good agreement with experimental values.