• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.61-68
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• 2001

Purpose: The C-14 urea breath test (C-14 UBT) is the most specific noninvasive method to detect Helicobacter (H) pylori infection. We investigated if the C-14 UBT can reflect the presence and degree of H. pylori detected by gastroduodenoscopic biopsies (GBx). Materials and methods: One hundred fifty patients (M:F=83:67, age $48.6{\pm}11.2$ yrs) underwent C-14 UBT, rapid urease test (CLO test) and GBx on the same day. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (137 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive (${\geq}200dpm$), Intermediate ($50{\sim}199dpm$) or negative (<50 dpm). The results of CLO tests were classified as positive or negative according to color change. The results of GBx on giemsa stain were graded 0 (normal) to 4 (diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT results with GBx grade as a gold standard. Results: In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.5%, 88.4%, 97.1%, 88.4% and 91.3%, respectively. However, the CLO test had sensitivity, specificity, PPV, NPV and accuracy of 83.2%, 81.4%, 91.8%, 81.4% and 82.7%, respectively. The quantitative values of the C-14 UBT were $45{\pm}27$ dpm in grade 0, $707{\pm}584dpm$ in grade 1, $1558{\pm}584dpm$ in grade 2, $1851{\pm}604dpm$ in grade 3, and $2719{\pm}892dpm$ in grade 4. A significant correlation (r=0.848, p<0.01) was found between C-14 UBT and the grade of distribution of H. pylori infection on GBx with giemsa stain. Conclusion: We conclude that the C-14 UBT is a highly accurate, simple and noninvasive method for the diagnosis of ongoing H. pylori infection and reflects the degree of bacterial distribution.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.229-234
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• 2008

Purpose: A urea breath test (UBT) using C-14 or C-13 has been developed for identifying Helicobacter (H) pylori infection on the basis of urease production with release of labeled $CO_2$. We investigated if the C-14 and C-13 UBT have the difference to reflect the presence and degree of H. pylori infection detected by gastro-duodenoscopic biopsies (CBx) in the same patients. Materials and methods: Thirty eight patients (M:F = 28:10, age $53.4{\pm}13.0$ yrs) with upper gastrointestinal symptoms such as indigestion, gastric fullness or pain consecutively underwent C-14 UBT, GBx and C-13 UBT within one week before medications. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (37 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive (${\ge}$ 200 dpm), intermediate (50-199 dpm) or negative (50 dpm). For the C-13 UBT, the results were classified as positive (${\ge}2.5\%_{\circ}$) or negative ($<2.5\%_{\circ}$). The results of GBx with Giemsa stain were graded 0 (normal) to 4 (diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT and C-13 UBT results with GBx grade as a gold standard. Results: The prevalence of H. pylori infection by GBx with Giemsa stain was 25/38 (65.8%). In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.0%, 92.3%, 95.8%, 91.7% and 92.1%, respectively. However, the C-13 UBT had sensitivity, specificity, PPV, NPV and accuracy of 96.0%, 84.6%, 92.3%, 91.7% and 92.1%, respectively. The more significant correlation in C-14 than C-13 UBT (r=0.948 vs r=0.819, p <0.001) was found between the value of UBT and the grade of distribution of H. pylori infection. Conclusion: We conclude that the diagnostic performance between C-14 and C-13 UBT to detect H. pylori infection is not significantly different, but the value of C-14 UBT more significantly reflects the degree of bacterial distribution.

• The korean journal of orthodontics
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• v.37 no.2 s.121
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• pp.98-113
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• 2007

Objective: The purpose of this study was to evaluate the displacement pattern and the stress distribution shown on a finite element model 3-D visualization of a dry human skull using CT during the retraction of upper anterior teeth. Methods: Experimental groups were differentiated into 8 groups according to corticotomy, anchorage (buccal: mini implant between the maxillary second premolar and first molar and second premolar reinforced with a mini Implant, palatal: mini implant between the maxillary first molar and second molar and mini implant on the midpalatal suture) and force application point (use of a power arm or not). Results: In cases where anterior teeth were retracted by a conventional T-loop arch wire, the anterior teeth tipped more postero-inferiorly and the posterior teeth moved slightly in a mesial direction. In cases where anterior teeth were retracted with corticotomy, the stress at the anterior bone segment was distributed widely and showed a smaller degree of tipping movement of the anterior teeth, but with a greater amount of displacement. In cases where anterior teeth were retracted from the buccal side with force applied to the mini implant placed between the maxillary second premolar and the first molar to the canine power arm, it showed that a smaller degree of tipping movement was generated than when force was applied to the second premolar reinforced with a mini implant from the canine bracket. In cases where anterior teeth were retracted from the palatal side with force applied to the mini implant on the midpalatal suture, it resulted in a greater degree of tipping movement than when force was applied to the mini implant between the maxillary first and second molars. Conclusion: The results of this study verifies the effects of corticotomies and the effects of controlling orthodontic force vectors during tooth movement.

• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.404-414
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• 1998

The purpose of this study was to investigate the influence of air pollution using epiphytic lichens on forest trees around Ulsan and Onsan industrial complex from April to June, 1997. The distribution of lichens was investigated at 58 sampled sites. In this study, 16 kinds of epiphytic lichens were recorded, of them, Lepraria sp. having a tolerance to air pollution showed the highest frequency as 30.85%, and in order of Lecanora strobilina(26.18%) and Parmelia austrosinensis(13.42%) unknown to tolerance of air pollution. The number of lichens was gradually decreased around industrial complex, where so - called "lichen desert" was detected. As being distant from the industrial complex, the mean degrees of cover were increased. The degrees of cover in the investigated sites ranged from I to V. According to $SO_2$ concentration limiting lichen's growth, the pattern of distribution of Cladonia sp., Dirinaria applanata, Parmelia austrosinensis, Lepraia sp. and Lecanora strobilina were dissimilar by sensitivity to air pollution Especially Lepraria sp. and Lecanora strobilina were widely distributed to degree of cover from I to V, and as the both had a similar distribution pattern, it could be inferred that Lecanora strobilina had also a tolerance to air pollution. The IAP values ranging from 0 to 64.3 were arranged into six groups and the investigated area was delineated into six IAP zones to represent degree of air environment. It was a high IAP value as being distant from industrial complex. The mare IAP increased, the more number of kinds of lichens increased. It was confirmed that the number of species, coverage and IAP value of epiphytic lichens showed a tendency to decrease of urban area and industrial complex.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.41-47
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• 1995

Tc-99m-MIBI(Sestamibi) myocardial SPECT along with T1-201 tomographic imaging has demonstrated wide application and high image qualify sufficient for the diagnosis of myocardial perfusion defect, which consequently reflects regional myocardial blood flow, The qualitative values of myocardial SPECT with Tc-99m-MIBI as well as the quantitative cases depend in some degree on the reconstruction techniques of multiple projections. Filtered backprojection(FBP) is the common standard for reconstruction rather than the complicated and time-consuming arithmetic methods. In FBP it Is known that the distribution of radioactivity in reconstructed transverse slices varies with the selected filter parameters such as cutoff frequencies and order(Butterworth case). The cutoff frequencies basically remove and decrease the true radioactive distribution and alter the pixel counts, which lead to underestimation of true counts in specific myocardial regions. In this study, we have investigated the effect of cutoff frequencies of reconstruction filter on the artifactually induced perfusion defects, which are often demonstrated near inferior and/or inferoseptal cardiac walls due to the intense hepatic uptake of Tc-99m-MIBI. A computerized method for identifying the relative degree of artifactual perfusion defect and for comparing those degrees along with the relative amount of hepatic uptake to myocardium was developed and patient images were studied to observe the quantitative degree of underestimation of myocardial perfusion, and to propose some reasonable thresh-old of cutoff frequency in the diagnosis of perfusion defect quantitatively. We concluded that from the quantitative viewpoint cutoff frequencies may be used as high as possible with the sacrifice of homogeneity of image quality, and those frequencies lower than the common 0.3 Nyquist frequency would reveal severe degradation of radio-active distribution near inferior and/or Inferoseptal myocardium when applying Butterworth or low pass filter.

• Korean Journal of Environment and Ecology
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• v.17 no.2
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• pp.153-168
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• 2003

Wangpicheon, which is located in Uljin-Gun, Korea, is threatened with various developments plan recently. To investigate the forest structure, actual vegetation and degree of green naturality(DGN) in Wangpicheon, survey was carried out within about 1km width from the stream. In the analysis of actual vegetation, the forest type around Wangpicheon is differentiated into 26 vegetation ones. In these, six Pinus densiflora - dominated vegetation types are appeared a great many of them. In DGN analysis, 70.8% of total area is covered by DGN 8 and 0.3% of total area is covered by DGN 9. According to the analysis of classification by TWINSPAN, the community was divided by three types of Pinus densiflora community and two types of Quercus spp. community i.e. Quercus mongolica and Q. vuliabitis community. The structure of communities were analyzed using importance percentage, and species and individuals, DBH distribution and similarity analysis were executed.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.680-689
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• 2011

A dynamic analysis procedure is developed to provide a comprehensive estimation of the dynamic response spectrum for locomotive's wheels running over a Pre-Stressed Concrete (PSC) box girder bridge on the Korea high speed railway. The wheel force spectrum with the bridge behavior are analyzed as the dynamic procedure for various running speeds (50~450km/h). The high-speed railway locomotive (KTX) is used as 38-degree of freedom system. Three displacements(vertical, lateral, and longitudinal) and three rotational components (pitching, rolling, and yawing). For one car-body and two bogies as well as five movements except pitching rotation components for four wheel axes forces are considered in the 38-degree of freedom model. Three dimensional frame element is used to model of the PSC box girder bridges, simply supported span length of 40m. The irregulation of rail-way is derived using the exponential spectrum density function under assumption of twelve level tracks conditions based on the normal probability procedure. The dynamic responses of bridge passing through the railway locomotive with high-speed analyzed by Newmark-${\beta}$ method and Runge-Kutta method are compared and contrasted considering the developed models of bridge, track and locomotive comprehensively. The dynamic analyses of wheel forces by Runge-Kutta method which are able to analyze the forces with high frequency running on the bridge and ground rail-way are conducted. Additionally, wheel forces spectrum and three rotational components of vehicle body for three typical running speeds is also presented.

• Journal of Acupuncture Research
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• v.31 no.2
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• pp.99-109
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• 2014

Objectives : The purpose of this study was to analysis the relationship between hours of smartphone use and neck pain in university students. Methods : A survey of 2,353 university students was conducted in Gyeonggi province and Incheon city using a self report questionnaire from April 1 to 11 2013. The questionnaire of questions regarding the hours of using smartphone, mainly used function in participant's smartphone and neck discomfort degree. Neck disability index(NDI) was used to evaluate degree of pain. The collected data were analyzed with the t-test and Kendall's tau test using the SPSS 21.0 program and R 3.1.0, respectively. Results : 1. Almost all of the survey participants(99.07 %) were smartphone users. 66.97 % of them answered that they use their smartphone daily more than 2 hours and 48.18 % of them answered that they use their smartphone 10 to 30 minutes everytime they use it. 2. The overall distribution of NDI scores was 'no disability(0~4 score, 62.92 %)', 'mild disability(5~14 score, 32.85 %)', 'moderate disability(15~24 score, 1.19 %)'. As a result of t-test, we found that the average NDI score for female students was significantly higher than the average NDI score for male students(p<0.05). 3. The Kendall's tau test revealed that total time spent daily using smartphones has a strong positive correlation with 'pain intensity', 'lifting', 'reading' 'headache', 'concentration', and 'driving'(p<0.05) in NDI. Also, time duration of one time smartphone usage has a strong positive correlation with 'pain intensity', 'lifting', 'reading', 'headache', 'concentration', 'work', and 'recreation'(p<0.05). 4. The Kendall's tau test revealed that total NDI scores have a significantly strong positive correlation with both of total time spent daily using smartphones(p<0.05) and time duration for one time smartphone usage(p<0.05). This results imply that long-time use of smartphone has a strong relationship with neck pain. Conclusions : The results of the study would be a good starting point for future studies to reduce the risks of chronic neck pain caused by smartphone usage.

• Computers and Concrete
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• v.21 no.3
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• pp.279-289
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• 2018

Hydration heat and thermal induced cracking have always been a fatal problem for massive concrete structures. In order to study a massive reinforced concrete wall of a storage tank for liquefied natural gas (LNG) during its construction, two mock-ups of $0.8m{\times}0.8m{\times}0.8m$ without and with metal corrugated pipes were designed based on the actual wall construction plan. Temperature distribution and strain development of both mock-ups were measured and compared inside and on the surface of them. Meanwhile, time-dependent thermal and mechanical properties of the concrete were tested standardly and introduced into the finite-element (FE) software with a proposed hydration degree model. According to the comparison results, the FE simulation of temperature field agreed well with the measured data. Besides, the maximum temperature rise was slightly higher and the shrinkage was generally larger in the mock-up without pipes, indicating that corrugated pipes could reduce concrete temperature and decrease shrinkage of surrounding concrete. In addition, the cooling rate decreased approximately linearly with the reduction of heat transfer coefficient h, implying that a target cooling curve can be achieved by calculating a desired coefficient h. Moreover, the maximum cooling rate did not necessarily decrease with the extension of demoulding time. It is better to remove the formwork at least after 116 hours after concrete casting, which promises lower risk of thermal cracking of early-age concrete.

• Korean Journal of Plant Taxonomy
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• v.34 no.1
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• pp.27-35
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• 2004

Three unrecorded fern species from the flora of Korea belonging to family Dryopteridaceae, Ctenitis maximowicziana, Dryopteris lunanensis, and D. dcipiens var. diplazioides, are found along the valley of Mt. Wolgak (alt. 275m) in Gwangju, Korea. C. maximawicziana is well distinguished from the rest of the species in the genus including C. sinii by the color and morphology of scales in basal part of petioles, shape of blades, and the presence of round-reniform shaped indusia. Dryopteris lunanensis is also well distinguished from its close relative, D. atrata, by the number of lateral pinnae, degree of division of first and/or second pinnules in lower pinnae of the blades, and distribution pattern of sori. Dryapteris decipiens var. diplazioides is distinguishable from type variety by degree of division in lower pinnae of the blades. In terms of morphology, var. diplazioides seems to be intermediate between a type variety and D. fuscipes.