• Journal of the Korean Geotechnical Society
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• v.39 no.5
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• pp.51-63
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• 2023

Numerical analysis was conducted to determine the effect of soil behavior by thawing and freezing of seasonal frozen soil on pile foundations. The analysis was performed using the finite element method (FEM) to simulate soil-pile interaction based on the atmosphere temperature change. Thermomechanical coupled modeling using FEM was applied with the temperature-dependent nonlinear properties of the frozen soil. The analysis model cases were applied to the MCR and HDP models to simulate the elastoplastic behavior of soil. The numerical analysis results were analyzed and compared with various conditions having different length and width sizes of the pile. The results of the numerical analysis showed t hat t he HDP model was relat ively passive, and t he aspect and magnit ude of t he bearing capacit y and displacement of the pile head were similar depending on the length and width of the pile conditions. The vertical displacement of the pile head by thawing and freezing of the ground showed a large variation in displacement for shorter length conditions. In the MCR model, the vertical displacement appeared in the maximum thaw settlement and frost heaving of 0.0387 and 0.0277 m, respectively. In the HDP model, the vertical displacement appeared in the maximum thaw settlement and frost heaving of 0.0367 and 0.0264 m, respectively. The results of the pile bearing capacity for the two elastoplastic models showed a larger difference in the width condition than the length condition of the pile, with a maximum of about 14.7% for the width L condition, a maximum of about 5.4% for M condition, and a maximum of about 5.3% for S condition. The significance of the effect on the displacement of the pile head and the bearing capacity depended on the pile-soil contact area, and the difference depended on the presence or absence of an active layer in the soil and its thickness.

• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.2
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• pp.99-109
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• 2023

Purpose: CT scan makes up for the weak point of the nuclear medicine image having a low resolution and also were used for attenuation correction on image reconstruction. Recently, many studies try to make use of CT images additionally, one of them is to measure the bone mineral density(BMD) using Quantitative CT(QCT) software. BMD exams are performed to scan lumbar and femur with DXA(Dual-Energy X-Ray Absorptiometry) in order to diagnose bone disease such as osteopenia, osteoporosis. The purpose of this study is to identify the usefulness of QCT_BMD analyzed with low dose CT images on L-spine Bone SPECT/CT comparing with DXA_BMD. Materials and Methods: Fifty five women over 50 years old (mean 66.4 ± 9.1) who took the both examinations(L-spine Bone SPECT/CT with SIEMENS Intevo 16 and DXA scan with GE Lunar prodigy advance) within 90 days from April 2017 to July 2022, BMD, T-score and disease classification were analyzed. Three-dimensional BMD was analyzed with low dose CT images acquired on L-spine Bone SPECT/CT scan on Mindways QCT PRO^TM software and two-dimensional BMD was analyzed on DXA scan. Basically, Lumbar 1-4 were analyzed and the patients who has lesion or spine implants on L-spine were excluded for this study. Pearson's correlation analysis was performed in BMD and T-score, chi-square test was performed in disease classification between QCT and DXA. Results: On 55 patients, the minimum of QCT_BMD was 18.10, maximum was 166.50, average was 82.71 ± 31.5 mg/cm³. And the minimum of DXA-BMD was 0.540, maximum was 1.302, average was 0.902 ± 0.201 g/cm², respectively. The result shows a strong statistical correlation between QCT_BMD and DXA_BMD(p<0.001, r=0.76). The minimum of QCT_T-score was -5.7, maximum was -0.1, average was -3.2 ± 1.3 and the minimum of DXA_T-score was -5.0, maximum was 1.7, average was -2.0 ± 1.3, respectively. The result shows a statistical correlation between QCT T-score and DXA T-score (p<0.001, r=0.66). On the disease classification, normal was 5, osteopenia was 25, osteoporosis was 25 in QCT and normal was 10, osteopenia was 25, osteoporosis was 20 in DXA. There was under-estimation of bone decrease relatively on DXA than QCT, but there was no significant differences statistically by chi-square test between QCT and DXA. Conclusion: Through this study, we could identify that the QCT measurement with low dose CT images QCT from L-Spine Bone SPECT/CT was reliable because of a strong statistical correlation between QCT_BMD and DXA_BMD. Bone SPECT/CT scan can provide three-dimensional information also BMD measurement with CT images. In the future, rather than various exams such as CT, BMD, Bone scan are performed, it will be possible to provide multipurpose information via only SPECT/CT scan. In addition, it will be very helpful clinically in the sense that we can provide a diagnosis of potential osteoporosis, especially in middle-aged patients.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.242-248
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• 2007

Purpose: To study the effect of recombinant human epidermal growth factor (rhEGF) on oral mucositis induced by cisplatin and radiotherapy in a mouse model. Materials and Methods: Twenty-four ICR mice were divided into three groups-the normal control group, the no rhEGF group (treatment with cisplatin and radiation) and the rhEGF group (treatment with cisplatin, radiation and rhEGF). A model of mucositis induced by cisplatin and radiotherapy was established by injecting mice with cisplatin (10 mg/kg) on day 1 and with radiation exposure (5 Gy/day) to the head and neck on days $1{\sim}5$. rhEGF was administered subcutaneously on days -1 to 0 (1 mg/kg/day) and on days 3 to 5 (1 mg/kg/day). Evaluation included body weight, oral intake, and histology. Results: For the comparison of the change of body weight between the rhEGF group and the no rhEGF group, a statistically significant difference was observed in the rhEGF group for the 5 days after day 3 of. the experiment. The rhEGF group and no rhEGF group had reduced food intake until day 5 of the experiment, and then the mice demonstrated increased food intake after day 13 of the of experiment. When the histological examination was conducted on day 7 after treatment with cisplatin and radiation, the rhEGF group showed a focal cellular reaction in the epidermal layer of the mucosa, while the no rhEGF group did not show inflammation of the oral mucosa. Conclusion: These findings suggest that rhEGF has a potential to reduce the oral mucositis burden in mice after treatment with cisplatin and radiation. The optimal dose, number and timing of the administration of rhEGF require further investigation.

• The Korean Journal of Nuclear Medicine
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• v.31 no.1
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• pp.73-82
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• 1997

Regional myocardial blood flow (rMBF) can be noninvasively quantified using N-13 ammonia and dynamic positron emission tomography (PET). The quantitative accuracy of the rMBF values, however, is affected by the distortion of myocardial PET images caused by finite PET image resolution and cardiac motion. Although different methods have been developed to correct the distortion typically classified as partial volume effect and spillover, the methods are too complex to employ in a routine clinical environment. We have developed a refined method incorporating a geometric model of the volume representation of a region-of-interest (ROI) into the two-compartment N-13 ammonia model. In the refined model, partial volume effect and spillover are conveniently corrected by an additional parameter in the mathematical model. To examine the accuracy of this approach, studies were performed in 9 coronary artery disease patients. Dynamic transaxial images (16 frames) were acquired with a GE $Advance^{TM}$ PET scanner simultaneous with intravenous injection of 20 mCi N-13 ammonia. rMBF was examined at rest and during pharmacologically (dipyridamole) induced coronary hyperemia. Three sectorial myocardium (septum, anterior wall and lateral wall) and blood pool time-activity curves were generated using dynamic images from manually drawn ROIs. The accuracy of rMBF values estimated by the refined method was examined by comparing to the values estimated using the conventional two-compartment model without partial volume effect correction rMBF values obtained by the refined method linearly correlated with rMBF values obtained by the conventional method (108 myocardial segments, correlation coefficient (r)=0.88). Additionally, underestimated rMBF values by the conventional method due to partial volume effect were corrected by theoretically predicted amount in the refined method (slope(m)=1.57). Spillover fraction estimated by the two methods agreed well (r=1.00, m=0.98). In conclusion, accurate rMBF values can be efficiently quantified by the refined method incorporating myocardium geometric information into the two-compartment model using N-13 ammonia and PET.

• Molecules and Cells
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• v.27 no.5
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• pp.591-599
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• 2009

Nicotinic acetylcholine receptors (nAChRs) play important roles in nervous system functions and are involved in a variety of diseases. We previously demonstrated that ginsenosides, the active ingredients of Panax ginseng, inhibit subsets of nAChR channel currents, but not ${\alpha}7$, expressed in Xenopus laevis oocytes. Mutation of the highly conserved Leu247 to Thr247 in the transmembrane domain 2 (TM2) channel pore region of ${\alpha}7$ nAChR induces alterations in channel gating properties and converts ${\alpha}7$ nAChR antagonists into agonists. In the present study, we assessed how point mutations in the Leu247 residue leading to various amino acids affect 20(S)-ginsenoside $Rg_3$ ($Rg_3$) activity against the ${\alpha}7$ nAChR. Mutation of L247 to L247A, L247D, L247E, L247I, L247S, and L247T, but not L247K, rendered mutant receptors sensitive to $Rg_3$. We further characterized $Rg_3$ regulation of L247T receptors. We found that $Rg_3$ inhibition of mutant ${\alpha}7$ nAChR channel currents was reversible and concentration-dependent. $Rg_3$ inhibition was strongly voltage-dependent and noncompetitive manner. These results indicate that the interaction between $Rg_3$ and mutant receptors might differ from its interaction with the wild-type receptor. To identify differences in $Rg_3$ interactions between wild-type and L247T receptors, we utilized docked modeling. This modeling revealed that $Rg_3$ forms hydrogen bonds with amino acids, such as Ser240 of subunit I and Thr244 of subunit II and V at the channel pore, whereas $Rg_3$ localizes at the interface of the two wild-type receptor subunits. These results indicate that mutation of Leu247 to Thr247 induces conformational changes in the wild-type receptor and provides a binding pocket for $Rg_3$ at the channel pore.

• Pediatric Infection and Vaccine
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• v.6 no.2
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• pp.245-252
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• 1999

Purpose : The aim of this study is to determine the age-specific seropositivity and the level of measles specific IgG in adults and to evaluate herd immunity to measles in Korea, the measles specific IgG were measured from the sera of adults over ages of 20 in Korea. Methods : 156 sera were collected from 156 out-patients over ages 20, who had visited clinical laboratory from June to July in 1997 at Korea University Ansan Hospital. The histories of natural measles or vaccination were not undertaken. Measles specific IgG titers were measured using ELISA method($SIA^{TM}$ Measles IgG Kit Co. St. Louis. Mo). Results : The results obtained from this study were as follows. 1) The seropositivity of measles specific IgG in adults was 94.9%. And there were no significant differences in their age and gender. 2) The mean measles-specific IgG titer was $238{\pm}84AU/mL$. And there were no significant differences in age and gender, except significant lower in 4th decades than other age groups. And there were no significant correlations between age and measles specific IgG level. Conclusion : In conclusion, a seropositivity of in adults was 94.9% which was higher than that of adolescents(91.2% in previous study), and antibody level was similar with adolescents. The herd immunity of the adults were considered to enough for protecting the transmission of measles in the community. For the eradication of measles in Korea, more efforts will be required to increase the vaccine coverage rate in children and adolescents.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.2
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• pp.106-111
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• 2018

This study was conducted to investigate the relationship between changes of rumen microflora and bloat in Jersey cow. Jersey cows (control age: 42 months, control weight: 558kg; treatment age: 29 months, treatment weight 507kg) were fed on the basis of dairy feeding management at dairy science division in National Institute of Animal Science. The change of microbial population in rumen was analyzed by using next generation sequencing (NGS) technologies due to metabolic disease. The diversity of Ruminococcus bromii, Bifidobacterium pseudolongum, Bifidobacterium merycicum and Butyrivibrio fibrisolvens known as major starch fermenting bacteria was increased more than 36-fold in bloated Jersey, while cellulolytic bacteria community such as Fibrobacter succinogenes, Ruminococcus albus and Ruminococcus flavefaciens was increased more than 12-fold in non-bloated Jersey. The proportion of bacteroidetes and firmicutes was 33.4% and 39.6% in non-bloated Jersey's rumen, while bacteroidetes and firmicutes were 24.9% and 55.1% in bloated Jersey's. In conclusion, the change of rumen microbial community, in particular the increase in starch fermenting bacteria, might have an effect to occur the bloat in Jersey cow.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.538-553
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• 1999

The purpose of this study was to compare the shear bond strength and the anticariogenicity of glass ionomer cement with conventional bonding resin and fluoride releasing resin. After the shear bond strength test, scanning electron microscopic observation was performed for the evaluation of the fracture patterns in each group. Under the polarizing light microscope, artificially induced carious lesions were evaluated and the lesion depths of the samples were measured using image analyzing program(Image-Pro $PLUS^{TM}$, USA). 50 sound maxillary premolars were used for the bond strength test and another 30 for the anticariogenic test. Data collected were analyzed statistically using Oneway-ANOVA and Scheffe test. The results were as follows: 1. Glass ionomer groups(G-III, IV, V) generally showed the lower bond strength values than resin groups(G-I, II). 2. Among the two resin groups, G-I showed the higher bond strength than G-II without statistically significant difference between them(p>.05). 3. Within glass ionomer groups, statistical significance was found between G-III and G-V with the superior bond strength in G-V (p<.05). 4. Under the SEM, adhesive failure was the predominant fracture pattern in G-I and II, whereas cohesive failures were mainly observed in G-III. In G-IV and V, mixed type of pattern where the both fracture patterns coexisted within samples could be seen. 5. In evaluation of the depth of artificially developed carious lesion, glass ionomer group showed shallower depth than resin groups with statistical significance between G-III and G-I, II(p<.05). Among resin groups, fluoride releasing resin(G-II) showed the shallower depth than conventional resin(G-I)(p<.05).

• Korean journal of communication and information
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• v.35
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• pp.250-291
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• 2006

This study examines the regulatory issues and introduction problems of TV-betting data broadcasts in Korea by in-depth interview with a panel group. TV-betting data broadcast services of card games and horse racing games are widely in use in Europe and other parts of the world. In order to carry out the study, a demo program of TV-betting data broadcast in the OCAP(OpenCableTM Application Platform Specification) system environment, which is the data broadcasting standard for digital cable broadcasts in Korea was exposed to the panel group and then they were interviewed after watching and using the program. The results could be summarized as below. First of all, while TV-betting data broadcasts have many elements of entertainment, the respondents thought that it would be difficult to introduce TV-betting in data broadcasts as in overseas countries largely due to social factors. In addition, in order to introduce TV-betting data broadcasts, they suggested that excessive speculativeness must be suppressed through a series of regulatory system devices, such as by guaranteeing credibility of the media based on safe security systems for transactions, scheduling programs with effective time constraints to prevent the games from running too frequently, limiting the betting values, and by prohibiting access to games through set-top boxes of other data broadcast subscribers. The general consensus was that TV-betting could be considered for gradual introduction within the governmental laws and regulations that would minimize its ill effects. Therefore, the government should formulate long-term regulations and policies for data broadcasts. Once the groundwork is laid for safe introduction of TV-betting on data broadcasts within the boundary of laws and regulations, interactive TV games are expected to be introduced in Korea not only for added functionality of entertainment but also for far-ranging development of data broadcast and new media industries.

• Radiation Oncology Journal
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• v.14 no.2
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• pp.149-158
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• 1996

Purpose : To get an accute steepness of dose gradients at outside the target volume in intracranial lesion and a less limitation of beam selection avoiding the high dose at normal brain tissue, this Photon Knife Radiosurgery System was developed in order to provide the three-dimensional dose distribution through the reconstruction of CT scan and the combined stereotactic trans-multiarc beam mode based on linear accelerator photon beam. Materials and methods : This stereotactic radiosurgery, Photon Knife based on linear accelerator photon beam was provided the non-coplanar multiarc and trans-multiarc irradiations. The stereotactic trans-multiarc beam mode can be obtained from the patient position in decubitus. This study has provided the 3-dimensional isodose curve and anatomical structures with the surface rendering technique. The dose distribution from the combined two trans-multiarcs (2M 2TM) was compared to that of four non-coplanar multiarcs (4M) with same collimator size of 25 mm in a diameter and total gantry movements. Results : In this study, it shows that the dose distributions of stereotactic beam mode are significantly depended on the selected couch and gantry angle in same collimator size. Practical dose distribution of combined stereotactic trans-multiarc beam has shown a more small rim thickness than that of the non-coplanar multiarc beam mode in axial, sagittal and coronal plane in our study. 3-Dimensional dose line displayed with surface rendering of irregular target shape is helpful to determine the target dose and to predict the prognosis in follow-up radiosurgery. Conclusions : 3-Dimensional dose line displayed with surface rendering of irregular target shape is essential in stereotactic radiosurgery. This combined stereotactic trans-multiarc beam has shown a less limitation of the selection couch and gantry beam angles for the target surrounding critical organs. It has shown that the dose distribution of combined trans-multiarc beam greatly depended on the couch and gantry angles. In our experiments, the absorbed dose has been decreased to $27%$ / mm in maximum at the interval of $50\%$ to $80\%$ of isodose line.