• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.111-116
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• 2018

This research examines the drop impact of an external cooling unit package of an air conditioner system. The packaging is composed of a shock-absorbing material, which protects the package contents by absorbing the impact energy and other parts for fixture. Accurate quantification of the impact acceleration experienced by the package contents is necessary to design an effective packaging with minimal volume and sufficient shock absorbing capacity. Explicit time integration was used for the drop impact analyses. A finite element model of the package was constructed, material testing and material model selection were carried out, and sensors for data acquisition were modeled to obtain accurate simulation results. The results were compared with real physical test data. Due to imprecise modeling of the damping, the acceleration and strain values predicted by the simulation were larger than those from physical test. However, the trend of the history data and the peak deceleration value in the direction of impact showed good agreements. Thus, the analysis model and scheme are suitable for the design of an air conditioner cooling unit package.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8281-8285
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• 2016

Background: Helicobacter pylori is a cause of chronic gastritis, peptic ulcer disease, and gastric malignancy, infection being a serious health problem in Thailand. Recently, clarithromycin resistant H. pylori strains represent the main cause of treatment failure. Therefore this study aimed to determine the prevalence and pattern of H. pylori resistance to clarithromycin in Suranaree University of Technology Hospital, Suranree University of Technology, Nakhon Ratchasima, Northeastern Thailand, Nakhon Ratchasima province, northeast of Thailand. Materials and Methods: This hospital-based cross-sectional study was carried out between June 2014 and February 2015 with 300 infected patients interviewed and from whom gastric mucosa specimens were collected and proven positive by histology. The gastric mucosa specimens were tested for H. pylori and clarithromycin resistance by 23S ribosomal RNA point mutations analysis using real-time polymerase chain reactions. Correlation of eradication rates with patterns of mutation were analyzed by chi-square test. Results: Of 300 infected patients, the majority were aged between 47-61 years (31.6%), female (52.3%), with monthly income between 10,000-15,000 Baht (57%), and had a history of alcohol drinking (59.3%). Patient symptoms were abdominal pain (48.6%), followed by iron deficiency anemia (35.3%). Papaya salad consumption (40.3%) was a possible risk factor for H. pylori infection. The prevalence of H. pylori strains resistant to clarithromycin was 76.2%. Among clarithromycin-resistant strains tested, all were due to the A2144G point mutation in the 23S rRNA gene. Among mutations group, wild type genotype, mutant strain mixed wild type and mutant genotype were 23.8%, 35.7% and 40.5% respectively. With the clarithromycin-based triple therapy regimen, the efficacy decreased by 70% for H. pylori eradication (P<0.01). Conclusions: Recent results indicate a high rate of H. pylori resistance to clarithromycin. Mixed of wild type and mutant genotype is the most common mutant genotype in Nakhon Ratchasima province, therefore the use of clarithromycin-based triple therapy an not advisable as an empiric first-line regimen for H. pylori eradication in northeast region of Thailand.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.57-58
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• 2006

The effects of lowering ECAP temperature during ECAP process and Post-ECAP annealing on microstructure, texture and mechanical properties of the AZ31 alloys have been investigated in the present study. The as-extruded materials were ECAP processed to 2 passes at 553K prior to subsequent pressing up to 6 passes at 523K or 493K. When this method of lowering ECAP temperature during ECAP was used, the rods could be successfully deformed up to 6 passes without any surface cracking. Grain refinement during ECAP process at 553K might have helped the material to endure further straining at lower deformation temperatures probably by increasing the strain accommodation effect by grain boundary sliding, causing stress relaxation. Texture modification during ECAP has a great influence on the strength of Mg alloys because HCP metals have limited number of slip systems. As slip is most prone to take place on basal planes in Mg at room temperature, the rotation of high fraction of basal planes to the directions favorable for slip as in ECAP decreases the yield stress appreciably. The strength of AZ31 Mg alloys increases with decrease of grain size if the texture is constant though ECAP deformation history is different. A standard positive strength dependence on the grain size for Mg alloys with the similar texture (Fig. 1) supports that the softening of ECAPed Mg alloys (a negative slope) typically observed despite the significant grain refinement is due to the texture modification where the rotation of basal planes occurs towards the orientation for easier slip. It could be predicted that if the original fiber texture is restored after ECAP treatment yielding marked grain refinement, yield stress as high as 500 MPa will be obtained at the grain size of ${\sim}1{\mu}m$. Differential speed rolling (DSR) with a high speed ratio between the upper and lower rolls was applied to alter the microstructure and texture of the AZ31 sheets. Significant grain refinement took place during the rolling owing to introduction of large shear deformation. Grain size as small as $1.4{\mu}m$ could be obtained at 423K after DSR. There was a good correlation between the (0002) pole intensity and tensile elongation. This result indicates that tensile ductility improvement in the asymmetrically rolled AZ31 Mg alloys is closely related to the weakening of basal texture during DSR. Further basal texture weakening occurred during annealing after DSR. According to Hall-Petch relation shown in Fig. 1, the strength of the asymmetrically rolled AZ31 is lower than that of the symmetrically rolled one when compared at the same grain size. This result was attributed to weakening of fiber texture during DSR. The DSRed AZ31, however, shows higher strength than the ECAPed AZ31 where texture has been completely replaced by a new texture associated with high Schmid factors.

• Journal of the Korean Geotechnical Society
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• v.30 no.4
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• pp.35-45
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• 2014

Limit equilibrium methods of slope stability analysis have been widely adopted mainly due to their simplicity and applicability. However, the conventional methods may not give reliable and convincing results for various geological conditions such as nonhomogeneous and anisotropic soils. Also, they do not take into account soil slope history nor the initial state of stress, for example excavation or fill placement. In contrast to the limit equilibrium analysis, the analysis of deformation and stress distribution by finite element method can deal with the complex loading sequence and the growth of inelastic zone with time. This paper proposes a technique to determine the critical slip surface as well as to calculate the factor of safety for shallow failure on partially saturated soil slope. Based on the effective stress field in finite element analysis, all stresses are estimated at each Gaussian point of elements. The search strategy for a noncircular critical slip surface along weak points is appropriate for rainfall-induced shallow slope failure. The change of unit weight by seepage force has an effect on the horizontal and vertical displacements on the soil slope. The Drucker-Prager failure criterion was adopted for stress-strain relation to calculate coupling hydraulic and mechanical behavior of the partially saturated soil slope.

• Tuberculosis and Respiratory Diseases
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• v.59 no.3
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• pp.266-271
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• 2005

Background : Ethambutol(EMB) is one of the first-line drugs included in short-course anti-tuberculosis therapy. The point mutations in embB gene have been speculated to be associated EMB resistance. However, detection of embB mutations at these positions have been observed in both EMB-susceptible isolates; thus, it remains controversial whether these mutations are associated with EMB resistance Methods : The 36 M. tuberculosis isolates were selected from clinical isolates which tested susceptible to EMB and resistant to at least one drug. DNA extracted from the isolates was analyzed by amplifying embB gene. The PCR products were purified and directly sequenced. We reviewed the history of past drug susceptibility test results. Results : Out of 36 EMB-susceptible strains, 3 strains (8.3%) had a mutation in codon 306 or 406 of the embB gene. These three strains had at least isoniazid resistance. They grew at 1.0 mcg/ml of EMB in Lowenstein-Jensen media. The patients of the strains were continuously smear-positive for over 3 years despite taking TB therapy. One strain had been EMB-resistant in past drug susceptibility tests. Conclusion : EMB-susceptible strains containing embB mutation may be caused by decreased viability in vitro test not by itself.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.235-246
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• 2003

Since the study of Lee et al.(1994) there have been some case studies on the set-up effect of driven piles in Korea country. However, comprehensive examination on the analyses of the set-up effect with various testing data has not been carried out. In particular, the analysis of the influence of soil type and pile shape on the set-up effect has not been reported. It is necessary to analyse the test results of production piles in order to apply the set-up effect of driven piles for the field engineering. In this study some test piling and analyses were performed to give basic information to the piling design as well as the research on the set-up effect in sandy soils. The analyses on the set-up effect were performed with the monitoring data obtained from the high-strain dynamic loading tests. It was shown that the set-up effect of driven piles was not only affected by soil type but also by soil formation history It turned out that the set-up effect in sandy soils was considerable one that should not be ignored in the field, and that the bearing capacity increase of pile is mainly caused by the increase of shaft resistance. It was shown that the set-up effect of closed pile was larger than that of opened pile in clayey soils, while the set-up effect of opened pile was larger than that of closed pile in sandy soils.

• Korean Journal of Microbiology
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• v.30 no.1
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• pp.15-29
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• 1992

Vibrio vuln$cus has been recognized as a pathogen of septicemia and wound infection, when the organism attacks high-risk persons with a history of hepatic disease. alcohol abuse. diabetes or any debilitative disease. Forty six strains of K vulnzjicus. isolated from 1025 marine specimens from May to Novemver for three years. from 1985 to 1987. were studied for their biochemical properties. growth requirements, serotype and drug susceptibilities. The isolates were different in their various biochemical reactions. Ninety-five percent of isolated strains were able to ferment lactose, while most strains didn't utilize sucrose in their biochemical test, for example ornithine, gelatin and mannitol were quite dit'ferent composition than those described in other reports. It was found that the biochemical test wasn't useful for identifying strain. The type of somatic 0 antiserum was determined in isolates from marine sources and in patients with Vibrio septicemia. In patient isolates. 1-2 group were 24% and 1-4 group were 42%. However. 02 group(33%) were more abundant in isolates from marine sources. Minimal inhibitory concentrations(M1Cs) of chloramphenicol, tetracycline. erythromycin and ampicillin were determinef for V vuln~ficus by broth dilution method. MIC90 was I , 0.25, :! and 4,ug/ml in patient isolates. 1, 0.25, 2 and 2 ,ug/ml in marine isolates. The divalent chelating agent, IDTA. inhibited the growth of V. vuln!'ficus at 6.25 mMlml of MIC90.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.111-119
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• 2007

Firemen are directly exposed to various harmful chemicals, physical factors and mental stress during rescue and fire-fighting. In fire extinguishing, unstable posture, poisonous gas, dust, high temperature and heavy equipments are possible hazardous factors. The alertness for emergency, shift work, job strain and stress are also possibly hazardous. Therefore, this study aimed to investigate the prevalence of musculo-skeletal symptoms and job stress and to determine risk factors in firemen. This study was carried out in a group of 226 firemen in Busan City, Korea. Standardized Nordic Questionnaire was used to investigate the prevalence of musculo-skeletal symptoms and Psycho-social Well-being Index (abbreviated PWI) was used to investigate the prevalence of job stress. General and occupational characteristics were included education, marital status, alcohol and smoking history, working duration, and work shift system. Body mass index (BMI) scores were calculated by physical examination including height and weight. Concerning musculo-skeletal complaints, the commonest site was neck, and shoulder, lower back, upper back were the next. Complaint site above one area of body was about 80%. From multiple logistic regression analysis, working duration was significant variable in musculo-skeletal symptoms. Odds ratio were 15.4 in working duration. About 16.8% was high risk stress group. From multiple logistic regression analysis, shift work and alcohol drinking were significant variables in PWI scores. Odds ratios were 2.25 in shift work. Accordingly, interventions are needed for health promotion of long term and shift worker.

• Economic and Environmental Geology
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• v.15 no.1
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• pp.41-47
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• 1982

Typical stratigraphic sequences of Paleozoic form the Baegunsan Syncline (equal to Hambaeg Syncline) and Taebaegsan Group is the basement in the southern part of Kangweon Province. Deformation pattern depends on their stratigraphic site and their internal properties. In the biotite schists and meta-sandstones of Pre-Cambrian sequences, flow folds and ptygmatic folds are developed, and high strain deformation is pervasive. Deformational patterns of Cambro-Ordovician are variable because of their various formations. Fracturing is pervasive in the Jangsan Quartzite and Daegi and Maggol Limestone. Welldeveloped slaty cleavage and angular folds of kink and chevron types are the prevailing structures of pelitic rocks. The most characteristic feature of limestone alternated with argillite is the "Compositional cleavage (Author's proposal)" known as the "Worm-eatern" structures. It was known that this structures have a sedimentary origin. But their preferred orienation of long axis of erosional lime holes, originated from tectonic deformation of folding. And this structures have the same character as the axial plane cleavages. Fracturing and long wave concentric folds are dominant characters of the Upper Paleozic sequences. In this area, two folds are superimposed. Field studying and analysis of structures show that the cross-folds of NS-direction are pervasive and were deformed by the EW-directional Baegunsan Syncline. The cross-folding is the major and penetrative deformation and prior to Baegunsan Syncline.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.69-75
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• 2004

Vibrio vulnificus is a halophilic bacterium frequently involved in human infection of seafood-associated primary septicemia and primary wound infection, mostly in men with over 40-years of age with underlying liver disease. The primary septicemia, which is the most common form of V. vulnificus infection in Korea, is defined as a systemic illness presenting fever or hypotension with recovery of V. vulnificus from blood or tissue without the apparent primary focus of infection. V. vulnificus typically do not produce acid from sucrose, but a case of primary septisemia was found in a patient at Chonnam K hospital in 1993 from whose blood a sucrose-fermenting strain was isolated. The patient was a 62-year-old man, heavy drinker, with underlying liver disease. He consumed a raw seafood dish two days before onset of the present illness. His symptoms were tenderness and swelling on the right foot. He rapidly developed septicemia, resulting in sudden death. V. vulnificus was isolated from the venous blood culture of the patient. On subculture, the isolate formed yellow colonies on TCBS and produced acid from sucrose. Because of these characteristics, species identification was not achieved by the API 20E and was delayed. Other characteristics of the isolate were identical to those of typical V. vulnificus. The isolate was common serotype O4A and possession of V. vulnificus-specific cytolysin gene was detected by PCR. The isolate was susceptible to all the antimicrobial agents tested including tetracycline, but was intermediate to colistin. In conclusion, it is important that microbiologists be aware of the presence of sucrose-positive V. vulnificus when he or she identifies gram-negative bacilli, which is isolated from the blood of patients with a recent history of raw seafood dish consumption.