• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.15-24
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• 2013

Purpose: With the demand of SPECT/CT increasing, the interest in complex diagnostic information of CT is rising along with the expansion of various studies on potential performance value. But the study on reduction of exposure dose generated by CT is not being conducted enough. Therefore, in this study, the goal is to identify how much dose reduction exists when performing the extremity bone SPECT/CT using the flat-panel CT. Materials and Methods: The extremity bone SPECT/CT was performed with two equipments -BrightView XCT (Philips Healthcare, Cleveland, USA) and Brilliance 16 CT (Philips Healthcare, Cleveland, USA)-to identify the exposed dose and image quality resulted by changing scan parameter (mAs) applying for both equipment respectively. The noise value of image and spatial resolution were measured with AAPM CT phantom. Tube voltage (kVp) was fixed to 120 kVp, tube current (mAs) calculated at different mA (20, 30, 40, 50, 60, 70, 80) was applied to both equipments respectively. DLP (dose length product) were calculated at the same distance at respective mAs. Also, we acquired images and % contrast with NEMA IEC body phantom to confirm the effect on image. The output of statistics was analyzed by SPSS ver.18. Results: Regarding AAPM phantom, the noise decreased as the tube current (mAs) increased and flat-panel had less noise than Helical CT. This difference increased at lower dose exposure. As to the evaluation of spatial resolution, we can differentiate the space up to 0.75 mm with both equipments. With scan parameter (mA) growing, the value of DLP increased up to 54-216 mGy cm at flat-panel CT and up to 177-709 mGy cm at Helical CT. Regarding NEMA IEC body phantom, same sphere with varied parameter (mA) shows that similar results. Conclusion: There is no significant differences of image quality in both flat-panel and Helical CT when the scan parameter (mA) is changed respectively. Moreover, we can identify the reduction of exposure dose and confirm %contrast analysis value with maintaining image quality. Therefore, at the extremity bone SPECT/CT requiring high spital resolution without the wide ROI, the flat-panel CT is considered to be more useful and it expected to result in the similar image quality with lower exposure dose compared to Helical CT. Additionally, through this study, we expect to help the reduction of the unnecessary exposure dose.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.322-335
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• 2003

Nutrient fluxes and sediment oxygen demands (SOD) were measured with intact sediment cores collected from three stations in the downstream of Nagdong River. The sediments were subjected to controlled oxic and hypoxic conditions and temperature gradients (from $10^{\circ}C$ to $30^{\circ}C$) of the overlying waters in laboratory batch system. The effect of temperature and labile layer thickness of the sediment on SOD were examined. $PO_4\;^{3-}$ and $NH_4\;^+$ fluxes were elevated above $20^{\circ}C$ and large mobilities were observed when they were coupled with a hypoxic and high-temperature condition. In the well oxygenated conditions, $PO_4\;^{3-}$ fluxes were negative or negligible but $NH_4\;^+$ fluxes ranged from 1.3 mg N $m^{-2}\;hr^{-1}$ to 2.3 $m^{-2}\;hr^{-1}$. Temperature quotients($Q_{10}$) of $PO_4\;^{3-}$ fluxes were 3.7 ${\sim}$ 7.3 ranges to have the most high values. $PO_4\;^{3-}$ and $NH_4\;^+$ fluxes had the logarithmic increase with temperature, while $NO_3\;^-$ was negatively absorbed to the sediment and linearly correlated with the temperature. $SiO_2$ fluxes showed no difference among oxic and hypoxic conditions and sediment texture. The nutrient fluxes would be closely correlated with pore water chemistry of sediments and activated by the top sediment layer composition such as labile organic matters or algal detritus. The ecological implications of the nutrient fluxes were discussed in terms of sources and sinks of nutrients coupled to algal productions in the Nagdong River.

• Korean Journal of Ecology and Environment
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• v.47 no.4
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• pp.282-291
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• 2014

This study was conducted to make distribution model of the Red-crowned Crane and the White-naped Crane according to the anthropogenic and natural factors affecting distribution of crane in Cheorwon, Korea. It was investigated that the impact power and its range of the indirect anthropogenic influence to feeding flock density in cranes from the road, residential area, military facilities, civilian control zone (CCZ), greenhouse and natural influence such as roosting site and available feeding area. Available feeding area is the most important factor for the crane's feeding site selection. The feeding flock density of the cranes near the residential area was lower than that of area far from the area, and tended to increase within 2.5 km distance. The increasing tendencies of feeding flock density from military facilities and high traffic volume road were similar, but the density in military facilities increased within 800 m, and the density from high traffic volume road increased within 2 km. These results suggested that residential area, military facilities and the road with high traffic volume had significant effect on foraging densities to the certain range. As the distance from the road with low traffic volume and roosting site increased, feeding flock density tended to decrease. The density of Red-crowned crane and White-naped crane inside the CCZ were respectively higher than those of outside the CCZ, especially for the Red-crowned crane. As a result, density of Red crowned cranes inside the CCZ was 5.2 times higher than that of outside, while that of white-naped cranes was 2.2 times bigger. If the density of greenhouse is lower than $40km^{-2}$, crane's feeding flock density in the low greenhouses density area was higher than that of high greenhouses density area. However, there was no difference in the feeding flock density if the density of the green houses is higher than $40km^{-2}$. The model for the Red-crowned Crane was related with available feeding area, distance from residential area, civilian control zone and distance from high traffic road. The model of the White-naped Crane was related with available feeding area, distance from roosting site and distance from lake. Finally, the estimated feeding flock density of cranes significantly correlated with density model according to the natural and anthropogenic factors.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.2
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• pp.133-139
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• 2004

Objective: To investigate the association of FSH receptor (FSHR) polymorphism at position 680 with outcomes of controlled ovarian hyper-stimulation for IVF-ET in Korean women. Design: Genetic polymorphism analysis. Materials and Methods: The FSHR polymorphism was analyzed by PCR-RFLP in 172 ovulatory women below the age of 40 year. Patients with polycystic ovary syndrome, endometriosis, or previous history of ovarian surgery were excluded. Results: Genotype distribution was 41.9% for the Asn/Asn, 47.7% for the Asn/Ser, and 10.5% for the Ser/Ser FSHR genotype group. There was no difference in age of subjects and infertility diagnosis between genotype groups. When the patients were grouped according to their FSHR genotype, the basal levels of FSH (day 3) were significantly different among the three groups ($6.0{\pm}0.3\;IU/L$ (mean $\pm$ SEM), $5.8{\pm}0.3\;IU/L$, and $8.6{\pm}1.2\;IU/L$ for the Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively, p=0.002). The Ser/Ser group showed a higher total doses of gonadotropins required to achieve ovulation induction, and a lower serum estradiol levels at the time of hCG administration compared with other two groups, but the differences were of no statistical significance. The numbers of oocytes retrieved were significantly different among the three groups ($8.6{\pm}0.8$, $9.9{\pm}0.6$, and $6.3{\pm}0.9$, for the Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively, p=0.049). Clinical pregnancy rates were 42.4%, 25.9%, and 29.4% for the Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively. Conclusion: Homozygous Ser/Ser genotype of FSHR polymorphism at position 680 was associated with decreased ovarian response to gonadotropin stimulation for IVF-ET.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6403-6409
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• 2013

Purpose: Biallelic germline variants of the 8-hydroxyguanine (8-OG) repair gene MYH have been associated with colorectal neoplasms that display somatic $G:C{\rightarrow}T:A$ transversions. However, the effect of single germline variants has not been widely studied, prompting the present investigation of monoallelic MYH variants and susceptibility to sporadic colorectal cancer (CRC) in a Chinese population. Patients and Methods: Between January 2006 and December 2012, 400 cases of sporadic CRC and 600 age- and sex-matched normal blood donors were screened randomly for 7 potentially pathogenic germline MYH exons using genetic testing technology. Variants of heterozygosity at the MYH locus were assessed in both sporadic cancer patients and healthy controls. Univariate and multivariate analyses were performed to determine risk factors for cancer onset. Results: Five monoallelic single nucleotide polymorphisms (SNPs) were identified in the 7 exon regions of MYH, which were detected in 75 (18.75%) of 400 CRC patients as well as 42 (7%) of 600 normal controls. The region of exon 1 proved to be a linked polymorphic region for the first time, a triple linked variant including exon 1-316 $G{\rightarrow}A$, exon 1-292 $G{\rightarrow}A$ and intron 1+11 $C{\rightarrow}T$, being identified in 13 CRC patients and 2 normal blood donors. A variant of base replacement, intron 10-2 $A{\rightarrow}G$, was identified in the exon 10 region in 21 cases and 7 controls, while a similar type of variant in the exon 13 region, intron 13+12 $C{\rightarrow}T$, was identified in 8 cases and 6 controls. Not the only but a newly missense variant in the present study, p. V463E (Exon 14+74 $T{\rightarrow}A$), was identified in exon 14 in 6 patients and 1 normal control. In exon 16, nt. 1678-80 del GTT with loss of heterozygosity (LOH) was identified in 27 CRC cases and 26 controls. There was no Y165C in exon 7 or G382D in exon 14, the hot-spot variants which have been reported most frequently in Caucasian studies. After univariate analysis and multivariate analysis, the linked variant in exon 1 region (p=0.002), intron 10-2 $A{\rightarrow}G$ (p=0.004) and p. V463E (p=0.036) in the MYH gene were selected as 3 independent risk factors for CRC. Conclusions: According to these results, the linked variant in Exon 1 region, Intron 10-2 $A{\rightarrow}G$ of base replacement and p. V463E of missense variant, the 3 heterozygosity variants of MYH gene in a Chinese population, may relate to the susceptibility to sporadic CRC. Lack of the hot-spot variants of Caucasians in the present study may due to the ethnic difference in MYH gene.

• Journal of the Korean Arthroscopy Society
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• v.15 no.2
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• pp.83-91
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• 2011

Purpose: Microfracture has been used as a first-line treatment to repair articular cartilage defects. In this study, a new technique using an extracelluar matrix biomembrane to cover the cartilage lesions after microfracture was evaluated in terms of cartilage repairability and clinical outcome compared with conventional microfracture technique in a prospective randomized trial. Materials and Methods: A total of 53 patients (59 cases) without osteoarthritis who had focal full thickness articular cartilage lesions were randomly assigned in two group. Seventeen patients (17 cases) underwent conventional microfracture procedure (control group) and thirty-six patients (42 cases) received microfracture and placing biomembrane cover (ArtiFilm$^{TM}$) concomitantly (experimental group). Clinical assessment was done through 6 months postoperatively using the subjective International Knee Documentation Committee IKDC questionnaire, and visual analog scale (VAS) for pain and satisfaction. Magnetic resonance imaging (MRI) was performed at 6 months after the operation in all patients. Results: In clinical outcomes, the significant difference was observed between both groups in IKDC, but not in VAS for pain and for satisfaction (final outcomes of IKDC, p=0.001; VAS for pain, p=0.074; VAS for satisfaction, p=0.194). The MRI showed good to complete defect fill (67 to 100%) in 33 patients (78.6%) of experimental group and 4 patients (23.5%) of control group, respectively. In control group, 9 of 17 patients (52.9%) showed poor defect fill (less than 33%), whereas 5 (11.9%) in experimental group (p=0.001). Assessment of peripheral integration revealed no gap formation in 35 patients (83.3%) in experimental group and 6 patients (35.3%) in control group (p=0.001). No serious complications or adverse effects related to the biomembrane were found. Conclusion: Good short-term follow-up clinical results were obtained in the group whose cartilage defects in the knee joint were covered with biomembrane after the microfracture, with the MRI findings confirming the excellent regeneration of the defective cartilage area. This suggests that the surgery to cover the defective area with biomembrane (ArtiFilm$^{TM}$) after the microfracture procedure is a safe, more effective treatment to induce cartilage regeneration.

• Journal of dental hygiene science
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• v.11 no.5
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• pp.445-453
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• 2011

Objectives : The purpose of this study was to determine of fluoride-releasing of orthodontic resin cements containing fluoride and compare decalcification of tooth attached fluoride and non-fluoride resin cements. Methods : Total eighty premolar tooth were used in this study. Forty tooth were used for fluoride releasing measurement and forty tooth were used for decalcification measurement. Each forty tooth were randomly divided into four groups, and brackets were attached on tooth surface with Blugloo, Light Bond, Orthofolw(experimental groups) and Transbond cement(control group). After brackets were attached on tooth surface, forty tooth were immersed in artificial salival and then the quantity of fluoride releasing was measured ever day for 8days and then three-days intervals for 3 weeks. Forty tooth were immersed in decalcification solution for 48hours and then degree of decalcification was measured as lesion area, ${\Delta}F$, and ${\Delta}Q$ using QLF. The data were analysed by one-way ANOVA and Pearson's correlation coefficient using SPSS 12.0 program. Results : Fluoride release of experimental groups was higher than control group(p<0.05). Cumulative fluoride release of experimental groups was also higher than control group(p<0.05). There were the highest release during first day. ${\Delta}F$, and ${\Delta}Q$ was high TB > BG > OF > LB (p<0.05). Change of ${\Delta}F$, and ${\Delta}Q$ was also high TB > BG > OF > LB (p<0.05). As for correlation between fluoride release and lesion area, ${\Delta}F$, and ${\Delta}Q$ showed negative correlation but there was no significant difference. Conclusions : This study shows that orthodontic reins cements containing fluoride release fluoride and prevent initial enamel decalcification caused by orthodontic treatment.

• Korean Journal of Plant Resources
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• v.30 no.5
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• pp.556-564
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• 2017

Appropriate soil temperature and early planting of potato is very important for the successful potato-soybean cropping system in central region of South Korea. This experiment was carried out to determine the effect of mulching materials on the growth and yield of potato (Solanum tuberosum L.). Five different mulch treatments were had been applied on an upland soil as follows ; no mulch (NM), transparent film (TF), transparent film + additional transparent film (TF + ATF), black film (BF), and black film + additional transparent film (ATF). In the period of sowing time to removing additional films, mean soil temperature of the treatments was in the order of TF+ATF > TF > BR+ATF > BF as $20.3^{\circ}C$ > $18.5^{\circ}C$ > $16.1^{\circ}C$ > $15.4^{\circ}C$, respectively and that of NM was $13.8^{\circ}C$. The accumulated soil temperature was TF > NM > BF during the removing additional films to earthing at inter-tillage. On the changes in the soil temperature during a whole day, the temperature in the BF was lower than NM during around 18:00 PM to 12:00 NM, while NM was higher than BF in the time period of 10:00AM to 21:00PM. The sequence of potato sprout emergence was 15 > 18 > 20 > 22 days of TF+ATF, TF, BF+ATF, and BF, respectively and that of NM was 24 days. Comparing to the NM, potato sprout emergence was observed on the TF+ATF treated plot as early as 9 days. At 10 days before harvest, the significant difference in the tuber dry weight had been observed and the sequence tuber weight was in the order of TF > TF+ATF > BF+ATF > BF > NM. The potato yields of TF, TF+ATF, and BF+ATF were increased of 40.7, 37.3, and 22% as compared to NM ($2,805kg\;10a^{-1}$), but almost same yield in the BF. The differences of tuber dry weight and potato yields was co-related with the temperature rise of soil by the application of mulching materials on soil. Based on these results, application of mulching film had been very effective to increase the tuber size and the yield of potato by the temperature rise during seedling stage of potato. Transparent mulching was better than black mulching especially for the emergence of sprout of potato in relation to minimizing cooling injury.

• Korea journal of population studies
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• v.25 no.2
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• pp.5-40
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• 2002

Using detailed data of women's work history, this study analyses the transition process between employment and non-employment over the life history in order to identity individual and structural determinants in the processes. Korean women comprise very heterogeneous groups in terms of work continuity: one group having a continuous work history and another having an interrupted work experience. While 4.0% of total women have stayed in the labor market since leaving school, 17.3% have not worked outside at all and remaining 87.9% have experienced into and out of the labor market at least once. On the average, the cumulated time of employment per woman is 8.2 years and the cumulated time of unemployment is 13.1 years. Thus Korean women work a total of only 38.5% of their whole lifetime after leaving school. We can conclude that the increase of the employment rate of married women in Korea since the 1970s has been due to the increase of the new entrants with short or little working careers into the labor market, not to the increase of women's work continuity on the whole. A women's educational achievement does not seem to be positively related to employment duration, contrary to the suggestion of the human capital theory, Rather, family variables, especially the existence of the child under 6 yens old, is a more significant determining factor for an individual's exit from employment. And there is little difference among different age cohorts which implies little improvement in the employment continuity of younger women. This study also documents the importance of structural variables, such as the type of occupation, as significant determining factors for the hazard rate. Specially women with professional jobs tend to stay longer in the labor market. Therefore, women's entry into more professional occupations is expected to contribute to the continuity of employment. Our results also show that duration-dependence is not spurious. When unobserved heterogeneity is controlled, the negative relation between the rate from employment and the duration of employment does not disappear.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.747-756
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• 1995

To find out the optimum application method of slow-releasing fertilizer(SRF) and conventional fertilizer(CF) with different fertilization rate under two culture methods[l0-day old seedling machine transplanting(MT) and direct-sowing on dry paddy(DS)] in the south-western region(clay loam soil) of Korea, used were Chosun slow-releasing fertilizer(silicate latex coated fertilizer: N-P$_2$O$_{5}$-K$_2$O =18-12-13) and conventional fertilizer. Plant height and number of tillers with different two culture methods were higher at MT than DS in early growth. The ratio of dry weight in heading stage was higher at CF than SRF in MT than DS and especially, SRF 80% + CF 20% than SRF 100% or CF 100%. Leaf area index (LAI) in heading stage was higher at CF in MT but higher at SRF in DS than their counterparts. Chlorophyll content was higher at SRF than in CF expect for heading stage(HS), especially in DS. It was highest at HS in CF without its difference during maximum tillering stage(MTS) and panicle formation stage(PFS), while highest at PFS in SRF with tendency of gradual increase and decrease before and after PFS, respectively. Heading was delayed 2~3 days at SRF in two cultrue methods and 4~5 days at SRF in DS in comparison with CF in MT with delay of 2 days at DS compared with MT. Culm length was longer at CF in MT and at SRF in DS than their counterparts. Panicle number per m was more at SRF and in DS. Filled grain ratio was higher at CF and in MT. Yield was obtained 101 and 100% at 100% and 80% level of SRF in DS respectively, and 96% at 80% level of CF in MT, compared with conventional application method (516kg /l0a), and increased 2~4% at DS and 0~3% at MT in SRF. Yield was high in order of 100%(SRF) =80%(SRF) + 20%(CF) > 100%(SRF) + 20%(CF) > 80%(SRF) at MT and 80%(SRF) + 20%(CF) =100%(SRF) > 80%(SRF) =100%(SRF) + 20%(CF) at DS.