• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.728-734
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• 2001

The purpose of this study was to investigate the effects of Er:YAG laser on cutting of efficacy of enamel and dentin in primary and permanent teeth. We used the enamel and dentin specimens of human teeth which contain the physiologic saline and maintain the pulpal pressure in dentinal tubules. Each specimen was exposed to Er:YAG laser with non-contact mode under different treatment condition of irradiation energy, pulse repetition rate. We investigated the cutting efficacy of Er:YAG laser by Scanning Intensity Microscopy, and obtained following results. 1. Cutting volume of enamel and dentin in primary and permanent teeth were increased by increasing the irradiation energy, pulse repetition rate. 2. Cutting volume of primary teeth was larger than that of permanent teeth. 3. Cutting volume of dentin was larger than that of enamel in primary and permanent teeth. From these results, Er:YAG laser would be more effective in cutting dentin than enamel, and in cutting primary teeth than permanent teeth for clinical application.

• The Journal of the Korean dental association
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• v.53 no.2
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• pp.132-142
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• 2015

Purpose : The objective of this research was to investigate an optimization of drill design factors for implant stability and efficacy through comparative evaluation by the cutting time, heat generation and initial stability. Materials and Methods : Three design factors were considered for the purpose of drill design optimization; the number of flute(2 flute, 3 flute), helix angle($15^{\circ}$, $25^{\circ}$) and drill tip shape(straight, 2-phase). Design factors were selected through comparative evaluation by temperature change, cutting time and ISQ value. Results : Heat generation and cutting time are influenced by all design factors(p<0.05). Drill tip shape was the only factors which influenced to the largest initial stability(p<0.05). Conclusion : Drills with 2 flutes, 2-phase formed drill tip, and 25 degrees of helix angle exhibit a better performance than other design.

• The Plant Pathology Journal
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• v.16 no.3
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• pp.162-165
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• 2000

Screening of effective fungicides, determination of effective fungicide application time and investigation of the emergence of resistant isolates to fungicides were conducted to establish effective chemical control strategy of gray blight of tea (Camellia sinensis) in Korea. Systemic fungicides, such as bitertanol, were effective for controlling gray blight when the fungicides were sprayed within 3 days after cutting tea leaves for harvest. Sprayed immediately after cutting, contact fungicides such as chlorothalonil were also effective, but control efficacy rapidly decreased with lengthening of the intervals between cutting and spraying. Korean isolates of P. longiseta and P. theae were still sensitive to bitertanol or fluazinam. However, the isolates highly insensitive to copper hydroxide or thiophanate-methyl have already emerged in Korea. Therefore, careful attention should be paid to use of fungicides and spraying programs for the effective control of gray blight of tea in Korea.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2007.11a
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• pp.11-15
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• 2007

Metabolomics is an emerging technology which makes it possible to evaluate change of biological system in response to the physiological, environmental alterations. It has advantages in the simplicity and sensitivity to analyze metabolites since the researcher can use cutting edge instrument, such as mass spectrometry and simple sample preparation method compared to genomics or proteomics. Nowadays this technology has been tried in pharmaceutical area to investigate toxicity and efficacy of drug candidates and drugs in preclinical test. The metabolomic applications on the pharmaceutics for early prediction on toxicity and efficacy are described in this presentation. The multivariate analysis to get metabolic fingerprinting and its relations with the physiological changes are investigated with several drugs. Feasibility of metabolomic application for pharmaceutical area would be suggested from those researches.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.32-44
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• 2001

The purpose of this study was to investigate the effects of Er : YAG laser on cutting efficacy and temperature changes of dentin. We used the dentin specimens of human premolars and molars which contain the physiologic saline and maintain the pulpal pressure in dentinal tubules. Each specimen was exposed to Er : YAG laser with non-contact handpiece type delivery system under different treatment condition of irradiation energy, pulse repetition rate, and exposure time. Two procedures were conducted by the presence of water flow during lasing. The specimens were grouped by thickness of dentin. We investigated the cavity pattern, volume, and temperature change of dentin specimen to determine the cutting efficacy and temperature rise of Er : YAG laser, and obtained following results. 1. Cutting volume of dentin was increased by increasing the irradiation energy, pulse repetition rate, and exposure time(P<0.05). 2. Margins of abulated cavities were sharp and clean and floors of cavities were conical in shape and showing smooth surfaces. Upper diameter of abulated cavities were increasing as laser parameter of irradiation energy, pulse repetition rate, and exposure time were increased. A few cracks were observed on abulated surfaces under treatment condition of laser parameter with 150mJ, 5Hz, and 5sec. 3. Temperature was increased as laser parameter of irradiation energy, pulse repetition rate, and exposure time were increased, and temperature rise was decreased as dentin thickness was increased(P<0.05). 4. Temperature rise was decreased under water flow compared with no water flow during laser exposure(P<0.05). From these results, we think that the method of using a Er:YAG laser would be effective and safe in cutting dentin for clinical application.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.272-285
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• 2003

This study was conducted to observe the microscopic structures of cavities formed after ablation of primary teeth, permanent teeth, enamel and dentin in using a bur and cavities formed after ablation using laser and the following results were obtained after comparing the effects of ablation. Using a #330 bur and Er:YAG laser irradiated at 150 mJ, 200 mJ, 250 mJ and 300 mJ all at the frequency of 5 Hz, 1 mm enamel and dentin samples were ablated and the ablation time was measured. In order to measure the surfaces ablated, 5 each of primary teeth and permanent teeth were ablated using a #330 bur and Er:YAG laser at 150 mJ, 200 mJ, 250 mJ and 300 mJ for 1 sec and the cross section and vertical section were observed. The following results were obtained : 1. Cutting time of Er:YAG laser was longer than that of conventinal high-speed bur regardless of teeth type. 2. Cutting on enamel, Cutting time of conventional high-speed bur in deciduous teeth was longer than in permanent teeth(P<0.05). But Er:YAG laser was not showed any difference between the deciduous and permanent teeth(P>0.05). 3. Cutting on dentin, Cutting time of conventional high-speed bur in permanent teeth was longer than deciduous teeth. Er:YAG laser of 150 mJ, 5 Hz in permanent teeth was longer than in deciduous teeth(p<0.05). But laser of other power did not showed mean difference. 4. The cavity surface treated with the convetional high-speed bur revealed a relatively flat appearance, almost covered with a debris-like smear layer. Cavity wall showed striped appearance because of blade of bur. 5. The cavity surface treated by the Er:YAG laser system was irregular or rough surface with the absence charring, carbonization, or cracking of the dentin. In addition, there was an absence of a smear layer. Cavity floor was round and relatively smooth. According to these results, cutting time of Er:YAG laser was almostly same in permanent and deciduous teeth, but more effective in dentin than enamel. Cutting the sample, Er:YAG laser was needed more time than conventional bur. But SEM findings suggested that laser device produced favorable surface characteristic(i.e, no smear layer, irregular surface, cracking).

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.683-693
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• 2001

The purpose of this study was to evaluate the effects of Er:YAG laser on cutting efficacy and its histologic findings. Dentin specimens of human premolars and molars were used and irradiated by Er:YAG laser with noncontact handpiece type delivery system under different treatment condition of irradiation time. Cavity pattern and volume were evaluated to determine the cutting efficacy and following results were obtained. 1. Cutting volume of sound dentin was getting larger with time immersed in water increase 2. With the condition of irradiation (150mJ, 10Hz, 30sec), surface irregularity was more increased in sound dentin comparing to carious dentin. For the light microscopic examination, dentinal tubules were opened and ash flecks and cracks were noted with inconsistence of dentinal tubules. 3. In case of 30 sec. irradiation in carious dentin, dark zone was limited to small focus whereas 1 min. irradiation, more wider, and cracks were noted in the perpendicular to direction of dentinal tubules. For the 2 min. irradiation, cavity was the widest and more cracks were found.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.104-110
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• 2015

This study was conducted for 3 years in an apple orchard to investigate the efficacy of the glufosinate-ammonium (GFA) SL for weed control in comparison to non-woven fabric mulch, sod culture and machinery cutting treatments. Glufosinate-ammonium SL 18% was applied with 2 to 3 times, and the extents of injury caused by the different weed control methods were also investigated during the 3 years. The highest level of weed control was obtained by glufosinate-ammonium 3 times spray (98.7%), followed by machinery cutting (95.1%), glufosinate-ammonium 2 times spray (81.5%) and natural sod culture (5.8%). Amounts of fruit production in three times application of glufosinate-ammonium 540 g a.i. $ha^{-1}$, twice application of GFA, machinery cutting, non-woven fabric processing, sod culture and untreated control were 27.2, 26.2, 25.3, 24.1, 20.4 and 13.3 kg, respectively. There was no toxicity symptom of glufosinate-ammonium on the whole tree such as fruit, bud, trunk, branch and flower during the 3 years.

• Tuberculosis and Respiratory Diseases
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• v.70 no.1
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• pp.43-50
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• 2011

Background: Open lung biopsy is used for diagnosis of diffuse infiltrative lung diseases (DILD), but it is invasive and relatively expensive procedure. Fluoroscopy-guided cutting needle lung biopsy (FCNLB) has merits of avoidance of admission and rapid diagnosis. But diagnostic accuracy and safety were not well known in the diagnosis of DILD. Methods: We included 52 patients (37 men, 15 women) having DILD on HRCT with dyspnea, except the patients who could be confidently diagnosed with clinical and HRCT findings. FCNLB was performed using 16G Ace cut needle (length 1.5 cm, diameter 2 mm) at the area of most active lesion on HRCT. Final diagnoses were made by the consensus. Results: The mean interval between the HRCT and FCNLB was 4.5 days. Most cases were performed one biopsy during 5~10 minutes. Specific diagnosis was obtained in 43 of 52 biopsies (83%). The most common diagnosis was nonspecific interstitial pneumonia (11 cases) and followed by cryptogenic organizing pneumonia (7 cases), diffuse alveolar hemorrhage and usual interstitial pneumonia (5 cases in each), hypersensitivity pneumonitis (3 cases), tuberculosis and drug induced interstitial pneumonitis (2 cases in each), the others are in one respectively. Mild complication was developed in 9 patients (8 pneumothorax, 1 hemoptysis). Most of complications were regressed without treatment except one case with chest tube insertion for pneumothorax. Conclusion: Fluoroscopy-guided 16 G cutting needle lung biopsy was an useful method for the diagnosis of DILD.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.637-642
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• 2010

Pre-treatment steps of fresh produce as Saengshik raw materials are followed by initial clean-up, dipping, primary washing, and cutting. Hypochlorous acid solution was applied in the dipping step to reduce natural microflora. Also, procedures were changed by cutting, dipping and then primary washing, and the efficacy of hypochlorus acid was evaluated. Potatoes, carrots, kales, and angelicas were submerged in water or 100 ppm of hypochlorous acid for 5 min. After initial clean-up, the aerobic plate counts of potatoes, carrots, kales and angelicas were 4.7, 5.3, 5.6, and 5.7 log CFU/g, respectively. When samples were submerged into water, it only reduced the population of natural microflora by 0.2 to 1.1 log CFU/g, whereas when treated with hypochlorous acid, it reduced the population by 0.5 to 2.8 log CFU/g. Reductions of natural microflora in green leafy vegetables were more highly achieved than bulbs such as potatoes and carrots. However, the numbers of natural microflora were increased after cutting step. To control the cross contamination at the cutting process, the process was changed as follows: initial clean-up, cutting, dipping in hypochlorous acid, and then primary washing. It showed effective reduction of the population by 2.3 to 3.2 log CFU/g. Hypochlorous acid solution could be useful as a sanitizer for surface washing of fresh vegetables.