• The Journal of Advanced Prosthodontics
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• v.10 no.4
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• pp.300-307
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• 2018

PURPOSE. To investigate the fatigue and fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic molar crowns on dental implants and human teeth. MATERIALS AND METHODS. Molar crowns (n=48; n=8/group) were fabricated of a lithium-disilicate-strengthened lithium aluminosilicate glass ceramic (N). Surfaces were polished (P) or glazed (G). Crowns were tested on human teeth (T) and implant-abutment analogues (I) simulating a chairside (C, crown bonded to abutment) or labside (L, screw channel) procedure for implant groups. Polished/glazed lithium disilicate (E) crowns (n=16) served as reference. Combined thermal cycling and mechanical loading (TC: $3000{\times}5^{\circ}C/3000{\times}55^{\circ}C$; ML: $1.2{\time}10^6$ cycles, 50 N) with antagonistic human molars (groups T) and steatite spheres (groups I) was performed under a chewing simulator. TCML crowns were then analyzed for failures (optical microscopy, SEM) and fracture force was determined. Data were statistically analyzed (Kolmogorow-Smirnov, one-way-ANOVA, post-hoc Bonferroni, ${\alpha}=.05$). RESULTS. All crowns survived TCML and showed small traces of wear. In human teeth groups, fracture forces of N crowns varied between $1214{\pm}293N$ (NPT) and $1324{\pm}498N$ (NGT), differing significantly ($P{\leq}.003$) from the polished reference EPT ($2044{\pm}302N$). Fracture forces in implant groups varied between $934{\pm}154N$ (NGI_L) and $1782{\pm}153N$ (NPI_C), providing higher values for the respective chairside crowns. Differences between polishing and glazing were not significant ($P{\geq}.066$) between crowns of identical materials and abutment support. CONCLUSION. Fracture resistance was influenced by the ceramic material, and partly by the tooth or implant situation and the clinical procedure (chairside/labside). Type of surface finish (polishing/glazing) had no significant influence. Clinical survival of the new glass ceramic may be comparable to lithium disilicate.

• Advances in concrete construction
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• v.10 no.5
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• pp.443-454
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• 2020

In recent years, many studies have been done on the performance of concrete containing glass powder (GP). For the purpose of widespread use of GP in concrete mixes, a knowledge of the performance of such a mixture after a fire is essential for the perspective of structural use. This research work was carried out to evaluate the performance of High Performance Concrete (HPC) made with GP after being exposed to elevated temperature. The studied mixtures include partial replacement of cement by GP with up to 30%. The mechanical performance and structural alterations were assessed after high temperature treatment from 200℃ to 800℃. The mechanical performance was evaluated by testing the specimens to the compressive and tensile strength. In addition, the mass loss and the porosity were measured to notice the structural alterations. Changes in microstructure due to temperature was also investigated by the X-ray diffraction (XRD) and thermal gravimetric analyses (TGA) as well as porosity adsorption tests. The results of the concrete strength tests showed a slight difference in compressive strength and the same tensile strength performance when replacing a part of the cement by GP. However, after high temperature exposition, concrete with GP showed better performance than the reference concrete for temperature below 600℃. But, after heating at 800℃, the strength of the concrete with GP drop slightly more than reference concrete. This is accompanied by an important increase in mass loss and water porosity. After the microstructure analysis, no important changes happened differently for concrete with GP at high temperature except a new calcium silica form appears after the 800℃ heating.

• Toxicological Research
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• v.22 no.1
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• pp.47-54
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• 2006

One of the main attractions of treatment with herbal medicine is its apparent lack of side effects compared with the drug therapies used in allopathic medicine. However, evidence from various countries suggest that Asian herbal medicine carry a significant risk of contamination with toxic heavy metals at levels that may seriously threaten health. The aims of this study were to analyze and compare concentrations of heavy metals in urine and hair from 184 patients taking herbal medicines in the form of decoctions and/or pills in comparison to 101 control subjects taking either Western or no medications. Levels of metal concentrations exceeding WHO reference values were observed in a number of hair and urine samples for all subjects. After adjusting for potential confounders, taking decoctions or pills was associated with higher levels of some metals (such as Cu, Pb in urine), as well a higher odds ratio of exceeding the upper limit of reference ranges for Pb, Hg in hair. In contrast, taking decoctions or pills was associated with lower levels of some metals (such as Cu in urine and Cd, Cu, Hg, Pb in hair), suggesting that some herbal medicines may have a chelating effect on heavy metals in the body. Overall, the results obtained in the study show a mixed picture and suggest that heavy metals contamination in herbs is sometimes present, but may also be counteracted by the potential for some herbal medicines to act as chelating agents. Further study must be followed to obtain more concrete evidence.

• Journal of Veterinary Clinics
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• v.22 no.4
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• pp.420-423
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• 2005

A 2-year-old 16-kg, intact female lindo was presented with weight loss and poor hair coat. Abnormal serum biochemical values included mild hypokalemia (3.9 mmol/L, reference range 4.37 to 5.35 mmol/L) and mild hyperglycemia (124 mg/dl, reference range 65 to 118 mg/dl). in the complete blood count and diagnostic imaging examination, abnormal changes wer not seen. The analysis of urine sample obtained from cystocentesis revealed glucosuria (> 100 mg/dl) and mild proteinuria. Repeated analysis after admission showed persistent glucosuria and hypokalemia. But blood glucose values did not exceed the renal threshold fur glucose reabsorption. To differentiate cause of the glucosuria, the glucose tolerance test and the low-dosage dexamethasone suppression test were indicated. Results of both tests were normal. In addition, the serum total thyroxine $(T_4)$ value was within normal range. The arterial blood gas analysis showed no remarkable changes. The fractional reabsorption rates of amino acids and phosphorus were calculated above $97\%$. Based on these findings, the dog was diagnosed as renal glucosuria due to proximal renal tubular dysfunction. But this persistent renal glucosuria with hypokalemia may be the initial sign of Fanconi's syndrome or proximal renal tubular acidosis.

• The Korean Journal of Emergency Medical Services
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• v.5 no.1
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• pp.7-14
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• 2001

The purposes of this study which was conducted by inquiring into some curricula for Emergency Medical Dispatchers(EMDs) are to introduce a curriculum into Korea and develop a textbook for training of the EMDs in Korea. The conclusions from this study were summarized as follows; (1) There are some professional demands in our Emergency Medical Dispatch field therefore, now it is necessary to set up an education system for the EMDs in Korea and give them a suitable name to this change. (2) Some historical turning points which are condensed from the developmental process in the USA. including "Medical Self Help" with no formal dispatch protocols, Medical Priority Dispatch System, Practice Standard, Dispatch Protocols will serve as a good reference for establishing and education system for the EMDs. (3) To effectively train the EMDs in Korea, we needed to be introduced to Emergency Medical Dispatch : National Standard of Curriculum from the U.S. Department of Transportation & the National Highway Traffic Safety Administration which is made up Basic Emergency Medical Concepts, Information Gatherin & Dispatch, Introduction to the Emergency Medical Dispatch Protocol Reference System(EMDPRS) & 32 Chief Complaint Types. (4) The introduced curriculum closely related to the medical director, the direct indirect medical control, the scope of practice in the USA, should be revised for the Emergency Medical Service System of Korea. But to reduce the developmental process & time, it is necessary to postpone the consideration on these factors until publishing a new textbook. (5) This study which gives the cornerstone about some developmental methods on textbook for EMDs will be helpful to build up an education system for EMDs such as Curriculum, EMD Certification, National Academy of Emergency Medical Dispatch to fit the Emergency Medical Service System of Korea in the future.

• The Journal of Advanced Prosthodontics
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• v.9 no.4
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• pp.287-293
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• 2017

PURPOSE. To compare the dimensional accuracy of three impression techniques- a separating foil impression, a custom tray impression, and a stock tray impression. MATERIALS AND METHODS. A machined mandibular complete-arch metal model with special modifications served as a master cast. Three different impression techniques (n = 6 in each group) were performed with addition-cured silicon materials: i) putty-wash technique with a prefabricated metal tray (MET) using putty and regular body, ii) single-phase impression with custom tray (CUS) using regular body material, and iii) two-stage technique with stock metal tray (SEP) using putty with a separating foil and regular body material. All impressions were poured with epoxy resin. Six different distances (four intra-abutment and two inter-abutment distances) were gauged on the metal master model and on the casts with a microscope in combination with calibrated measuring software. The differences of the evaluated distances between the reference and the three test groups were calculated and expressed as mean (${\pm}SD$). Additionally, the 95% confidence intervals were calculated and significant differences between the experimental groups were assumed when confidence intervals did not overlap. RESULTS. Dimensional changes compared to reference values varied between -74.01 and $32.57{\mu}m$ (MET), -78.86 and 30.84 (CUS), and between -92.20 and 30.98 (SEP). For the intra-abutment distances, no significant differences among the experimental groups were detected. CUS showed a significantly higher dimensional accuracy for the inter-abutment distances with -0.02 and -0.08 percentage deviation compared to MET and SEP. CONCLUSION. The separation foil technique is a simple alternative to the custom tray technique for single tooth restorations, while limitations may exist for extended restorations with multiple abutment teeth.

• Imaging Science in Dentistry
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• v.38 no.2
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• pp.73-79
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• 2008

Purpose: To assess the internal echo intensity and morphological variability of masseter muscles on ultrasonography and to establish diagnostic criterion of estimation. Materials and Methods: Participants consisted of 50 young adults (male 25, female 25) without pathologic conditions and with full natural dentitions. Sonographic examinations were done with real time ultrasound equipment as Logiq 500 (GE Medical Systems, Seoul, Korea) at 3 parts according to lines paralleling with ala-tragus line as reference line. The thickness and area of masseter muscles according to reference line in cross-sectional images were measured at rest and at maximum contraction. The visibility and width of the internal echogenic intensity of the masseter muscles were also assessed and the muscle appearance was classified into 4 types. Data were statistically analyzed by paired t-test and $x^2$-test. Results: 1. When comparing the thickness and area of masseter muscles concerning with gender, there was few significant difference between right and left sides, however, there were significant differences between males and females except for the greatest thickness of left side. 2. The changes of the greatest thickness and the area between rest and maximum contraction showed that the part of the least thickness manifested more increase at maximum contraction. 3. Each part the manifestations of the internal echogenic intensity of the masseter muscles were different depending on the locations. But there was no statistically significance. Conclusion: Changes of muscles thickness with contraction and internal echogenic intensity with locations showed great disparity within the masseter muscles, which will be diagnostic criteria for pathophysiologic and anatomic changes of masseter muscles.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.1942-1951
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• 2017

Campylobacter jejuni and Campylobacter coli are important foodborne pathogenic bacteria, particularly in poultry meat. In this study, the presence of extracellular DNase activity was investigated for biofilm-deficient Campylobacter strains versus biofilm-forming Campylobacter strains isolated from chickens, to understand the relationship between extracellular DNase activity and biofilm formation. A biofilm-forming reference strain, C. jejuni NCTC11168, was co-incubated with biofilm non-forming strains isolated from raw chickens or their supernatants. The biofilm non-forming strains or supernatants significantly prohibited the biofilm formation of C. jejuni NCTC11168. In addition, the strains degraded pre-formed biofilms of C. jejuni NCTC11168. Degradation of C. jejuni NCTC11168 biofilm was confirmed after treatment with the supernatant of the biofilm non-forming strain 2-1 by confocal laser scanning microscopy. Quantitative analysis of the biofilm matrix revealed reduction of extracellular DNA (16%) and proteins (8.7%) after treatment. Whereas the biofilm-forming strains C. jejuni Y23-5 and C. coli 34-3 isolated from raw chickens and the C. jejuni NCTC11168 reference strain showed no extracellular DNase activity against their own genomic DNA, most biofilm non-forming strains tested, including C. jejuni 2-1, C. coli 34-1, and C. jejuni 63-1, exhibited obvious extracellular DNase activities against their own or 11168 genomic DNA, except for one biofilm non-former, C. jejuni 22-1. Our results suggest that extracellular DNase activity is a common feature suppressing biofilm formation among biofilm non-forming C. jejuni or C. coli strains of chicken origin.

• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.91-101
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• 2001

In order to propose a optimum method increasing accuracy and reproducibility in analysis of urine lead levels, we compared matrix modifier addition method and microwave digestion method. The results were as follows ; 1. Where the concentration of $Pd(NO_3)_2$(matrix modifier) was $50mg/{\ell}$, and ashing temperature was $900^{\circ}C$, the results were optimum. In case of matrix modifier addition method, the average coefficient of variation (CV) of normal man was 24.1%, and lead worker was 7.9%. The average urine lead levels of standard were $10.42\mu{g}/{\ell}$ and $19.89\mu{g}/{\ell}$ , the accuracies compared to reference values were 97.0% and 92.6%, respectively. 2. Microwave digestion temperature($160~180^{\circ}C$), time(15~25min) and the ratio of urine/ashing acid(1:1~4:1) did not significantly affect lead absorbance and background absorbance. Therefore we set up a optimum analytical conditions as follows: temperature, $160^{\circ}C$; time, 15min; the ratio of urine/ashing acid, 4:1. after samples were digested by the above analytical conditions, lead absorbance and background absorbance was measured at $450^{\circ}C$ as ashing temperature. The average coefficient of variation (CV) of normal man was 12.4%, and lead worker was 6.2%. The average urine lead levels of standard urine were $10.66\mu{g}/{\ell}$ and $23.31\mu{g}/{\ell}$, the accuracies compared to reference values were 99.3% and 103.9%, respectively. From the results, we suggest that microwave digestion method is a more favorable method than matrix modifier addition method because of easiness to reduce organic matter, possibility to analysis at low temperature and accuracy.

• International Journal of Highway Engineering
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• v.2 no.4 s.6
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• pp.111-122
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• 2000

PMS(Pavement Management System) has been developed and/or operated for the freeway and national highway systems in Korea. There is, however, no municipal PMS that is necessary in many cities for efficient management of their roadways. In this study, a municipal Prototype PMS is developed. The Prototype PMS is designed to be operated on PC base. It uses GIS interface for user friendliness that applies color graphics, text and distress pictures to display pavement conditions and rehabilitation information for both current and historical situations. The computer program of the prototype PMS consists of four major functions(inquiry, analysis, data management, and print). Especially, prioritization and M&R(Maintenance and Rehabilitation) alternative selection procedure is designed to be flexible so that the users can modify the decision criteria whenever it is necessary. Database items of the Prototype PMS is carefully selected for the objectives and size of municipal PMS. Reference point method is basically used for the location referencing in the Database. The unit section consists of each loom segment of the road for effective management.