• Journal of Embryo Transfer
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• v.27 no.3
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• pp.127-131
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• 2012

This study was performed to investigate the effects of parity and season on the embryo production in superovulated Hanwoo cows. Superovulation was performed from 1 to 8 times by repeated superovulation treatment of Hanwoo cows (n = 22). Irrespective of estrous cycle, donor cows were received a CIDR, progesterone (50 mg) and estradiol benzoate (2.5 mg). After 4.5 days, the donor cows were superovulated with total 28AU FSH (Antorin R-10) administrated twice daily in a decreasing dose for 4 days. On $6^{th}$ and $7^{th}$ of FSH injection, 2.5 mg and 15 mg $PGF_2{\alpha}$ were injected i.m, respectively. CIDR was removed at the $7^{th}$ FSH injection. The donor cows received $200{\mu}g$GnRH at 48 hrs after $1^{st}$ $PGF_2{\alpha}$ injection. The donor cows were artificially inseminated three times after estrous detection at 12 hr intervals and embryos were recovered 7 days after estrous detection. The mean number of total ova, transferrable embryos, degenerated embryos and unfertilized oocytes were $11.6{\pm}7.9$, $5.5{\pm}4.4$, $3.0{\pm}3.3$ and $2.6{\pm}4.1$ per donor cows, respectively. A higher number of total ova were recovered in parity 3~5 ($14.3{\pm}1.3$) than 1~2 ($8.9{\pm}1.9$, P<0.05). The number of recovered normal embryos is significantly higher in parity 3~5 ($7.3{\pm}0.8$) than that of over 6 ($3.7{\pm}1.5$). Significantly higher number of total ova and normal embryos were recovered in summer ($16.4{\pm}2.3$, $8.1{\pm}1.4$) than in autumn ($10.1{\pm}1.8$, $4.5{\pm}1.1$) and winter ($6.3{\pm}1.8$, $3.3{\pm}1.1$), respectively (P<0.05). Transferable embryos were significantly higher in summer ($7.6{\pm}1.3$) than in winter ($3.0{\pm}1.0$, P< 0.05). The results were showed that parity and season affecting on the production of embryos in superovulated Hanwoo.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.365-374
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• 2015

The regular quality assurance (RQA) of X-ray images is essential for maintaining a high accuracy of diagnosis. This study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) of a computed radiography (CR) system for various periods of use from 2006 to 2015. We measured the pre-sampling MTF using the edge method and RQA 5 based on commission standard international electro-technical commission (IEC). The spatial frequencies corresponding to the 50% MTF for the CR systems in 2006, 2009, 2012 and 2015 were 1.54, 1.14, 1.12, and $1.38mm^{-1}$, respectively and the10% MTF for 2006, 2009, 2012, and 2015 were 2.68, 2.44, 2.44, and $2.46mm^{-1}$, respectively. In the NPS results, the CR systems showed the best noise distribution in 2006, and with the quality of distributions in the order of 2015, 2009, and 2012. At peak DQE and DQE at $1mm^{-1}$, the CR systems showed the best efficiency in 2006, and showed better efficiency in order of 2015, 2009, and 2012. Because the eraser lamp in the CR systems was replaced, the image quality in 2015 was superior to those in 2009 and 2012. This study can be incorporated into used in clinical QA requiring performance and evaluation of the performance of the CR systems.

• Journal of Embryo Transfer
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• v.21 no.3
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• pp.191-198
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• 2006

The objectives of this study was to produce valuable offsprings of Hanwoo and Jeju black cattle using in vivo embryo production and embryo transfer techniques during 5 years ($2001{\sim}2005$) in Jeju. Two hundred and eighty six Hanwoo and sixty nine Jeju black cattles, at random stages of the estrous cycle, received a CIDR. Seven days later, the animals were superovulated with a total of 400 mg pFSH ($Folltropin^{(R)}-V$) administered twice daily in constant doses (each 50 mg) over 4 days. On the 6th administration of FSH, CIDR was withdrawn and 25 mg $PGF_{2{\alpha}}$ was administered. Cows were artificially inseminated thrice after estrous detection at 12 hr intervals. The cows received $250{\mu}g$ GnRH at the time of 2nd insemination. Embryos were recovered 7 or 8 days after the 1st insemination. Recipients were synchronized with donors by insertion of a CIDR for 7 days and administration of 25 mg $PGF_{2{\alpha}}$ at the time of CIDR removal. The collected embryos were transferred to 1,219 recipients by 6 transfer persons. The mean numbers of total ova and transferable embryos from Hanwoo and Jeju black cattle donors were 7.4 and 4.7, respectively The number of transferable embryos differed between Hanwoo (5.0) and Jeju black cattle (3.5, p<0.05), while that of total ova did not differ. Repeated superovulation treatments decreased (p<0.05) the ratio of numbers of the flushed animals vs. superovulated animals in Jeju black cattle, and the numbers of total ova and transferable embryos in Hanwoo. More transferable embryos were collected at summer (5.6) than winter (2.9, p<0.01). The mean pregnancy rate was 40%. The pregnancy.ate was affected by transfer year (2001<2004, p<0.05) and transfer person ($33.0{\sim}41.9%$, p<0.01), while not by donor (embryo) breed. These results showed that in vivo embryo preduction and embryo transfer techniques using CIDR for Hanwoo and Jeju black cattle donors as well as recipient, regardless of their estrous cycle, may enable a stable embryo production and recipient preparation.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.5
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• pp.119-134
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• 2018

Today, many firms face the environment of high uncertainty and severe competition due to the rapid technology development and the diverse needs of customers. In the business environment, one of the most important ways to gain sustainable competitive advantage and future growth engine is related to NPD (New Product Development), which is a very important issue for practice and academia. Thus, this study intends to provide new values to practitioners and researchers related to NPD by analyzing current research trends and future trends in NPD field. For this, we bibliometrically analyzed keyword networks which consist of keywords that were already published in the eminent journals from Scopus database to generate insights that have not been captured in the previous reviews on the topic. As a result, we could understand the extant research streams in NPD field, and suggest the changes of specific research topics based on the connected relationships among keywords over the time. In addition, we also foresaw the general future research trends in NPD field based on the keywords according to preferential attachment processes. Through this study, it was confirmed that NPD keyword network is a small world network that follows the distribution of power law and the growth of network is formed by link formation by keyword preferential attachment. In addition, through component analysis and centrality analysis, keywords such as Innovation, New product innovation, Risk management, Concurrent engineering, Research and development, and Product life cycle management are highly centralized in NPD keyword network. On the other hand, as a result of examining the change of preferential attachment of keywords over the time, we suggested the required new research direction including i) NPD collaboration with suppliers, ii) NPD considering market uncertainty, iii) NPD considering convergence with the other academic areas like technology management and knowledge management, iv) NPD from SME(Small and medium enterprises) perspective. The results of this study can be used to determine the research trends of NPD and the new research themes for interdisciplinary studies with other disciplines.

• Journal of Radiation Protection and Research
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• v.35 no.1
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• pp.34-42
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• 2010

With the expanded use of radiation in modern medical practices, the most important issue in regards to efforts to reduce individual exposure dose is quality assurance. Therefore in order to study the present condition of quality assurance, the Gwangju Metropolitan City area was divided into five districts each containing ten hospitals. Four experiments were conducted: a reproducibility experiment for kVp, mA, and examination time (sec) intensity of illumination; half-value layer (HVL) measurement; and beam perpendicularity test matching experiment. The tube voltage reproducibility experiment for all fifty hospitals resulted in a 95.33% passing rate and mA and examination time both resulted in a 77.0% passing rate. The passing rate for intensity of illumination was 86.0% and 52.0% for HVL, which was the lowest passing rate of all four factors. For the beam perpendicularity test matching experiment, generally the central flux is matched to within $1.5^{\circ}$. Of all fifty hospitals 30.0% were beyond $3^{\circ}$. The results of the survey showed that 58% responded that they knew about quality assurance cycle. All fifty respondents stated that they have not received any training in regards to quality assurance at their current place of employment. Although quality assurance is making relative progress, the most urgent issue is awareness of the importance of quality assurance. Therefore, the implementation of professional training focusing on safety management and accurate quality assurance of radiation will reduce the exposure to radiation for radiologists and patients and higher quality imaging using less dosage will also be possible.

• Korean Journal of Plant Resources
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• v.27 no.4
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• pp.380-391
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• 2014

Plants as well as crops are damaged by a combination of the hot and dry winds that has been a major factor in the reduction of crop production. A means to protect them from damaging conditions is to consider a coating material. In this study, we established laboratory screening methods to find a coating material to protect a crop from rapid transpiration caused by various factors. In a test measuring the weight loss of kidney bean seedlings for 6 days, Avion treatments decreased its weight loss (P=0.05). Owing to long-time spend in completing this assay, we performed a more simple method using a cobalt chloride paper strip, which changes from blue to red colors under water condition. Beewax, guagum, paraffin liquid, soybean oil, and PE-635 gave a waterproofing effect above 37 and 43% at 0.5 and 1 h after treatment, respectively. However, these tested materials did not show significant waterproofing results at 2 h. Although the methods produced reasonable results, a screening method to obtain more objective data is needed. An alternative is to use an instrument that can detect the transpiration of crop leaves. In a preliminary test using barley leaves, a portable photosynthesis system showed transpiration inhibition of 2% soybean oil and 10 times-diluted Avion under field conditions. In another test using the leaves of maize seedlings and apricot tree, 2% liquid paraffin and plant oils such as apricot oil, linseed oil, olive oil, and soybean oil showed significant transpiration inhibition (P=0.05). Especially, paraffin liquid and soybean oil selected from above tests gave good transpiration inhibitory effects against rice at 2%. In addition, the mixture of 2% soybean oil and a spreader showed more elevated inhibition results comparing with soybean oil or the spreader alone indicating that the spreader may be attributed to more uniform diffusion of the hydrophobic material onto the leaf surface of maize seedlings. The hydrophobic material coated physically the stomata and cuticle layers on leaf surfaces of rice. These hydrophobic materials screened in this study are expected to be used as plant coating materials.

• Journal of dental hygiene science
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• v.16 no.2
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• pp.150-156
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• 2016

In this study, the surface treatment of a self-cured temporary crown was polished using a denture bur, silicone bur, or pumice. The color stability of the temporary crown resin specimen was evaluated by immersing it in coffee, and cola, wine, beer, red pepper paste, or soybean paste. Two-hundred eighty-five identical resin specimens with six types of staining solution and three types of surface treatment were placed in a shaking incubator at $37^{\circ}C$. The degree of discoloration was observed using a time-lapse recording of days 1, 5, and 7. $L^*$, $a^*$, and $b^*$ were measured using a spectrophotometer, which shows the quantitative value of discoloration, and statistically processed after calculating ${\Delta}E^*$. The results show that as time passed, all the specimens showed a color change (p<0.001). The amount of color change was the greatest in in crowns with denture bur polishing on the day 1, 5, and 7. As the precipitation time increased, the ${\Delta}E^*$ value was also increased. Of the specimens immersed on day 1, the greatest color change in crowns polished with denture bur was observed in those immersed in red pepper paste, while the smallest color change was observed in those immersed in cola. On days 5 and 7, the greatest color change in crowns polished with denture bur was observed in those immersed in red wine. Crowns polished with silicone bur and immersed in soybean paste exhibited the smallest color change. Based on the results, compared to pumice polishing, silicone bur polishing results in better color stability, saves time and money, and is recommended for patients with temporary crowns.

• Clinical and Experimental Pediatrics
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• v.53 no.3
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• pp.307-313
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• 2010

Purpose : Results of the Korea National Health Screening Program for Infants and Children, which was launched in November 2007, were evaluated for future research and policy development. Methods : Data from a total of 2,729,340 cases were analyzed. Five visiting ages, such as 4, 9, 18, 30, and 60 months, were included. Several parameters such as stunting, obesity, and positive rate of developmental screening were also analyzed. Telephone survey was performed in 1,035 users. For the provider survey, 262 doctors participated in our study. Results : The overall participation rate of users was 35.3%. This participation rate showed a decrement tendency to old age and low income. Only 6.9% of users participated in oral screening. Health screening was performed mainly in private clinics (82.6%). The recall rate of 4 months program users at the age of 9 months was 57.3%. The positive rate of screening was 3.1%, and was higher in the low-income group. By telephone survey, users reported that questionnaires were not difficult (94%) and overall satisfaction was good (73%). Longer duration of counseling was related with more satisfied users. Counseling and health education were helpful to users (73.2%). Doctors agreed that this program was helpful to children (98.5%). Conclusion : Korea National Health Screening Program for Infants and Children was launched successfully. Participation rate should be improved, and a quality control program needs to be developed. More intensive support following this program for children of low-income families may lead to effective interventions in controlling health inequality. Periodic update of guidelines is also needed.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.341-351
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• 2008

This study investigated the effect of intermittent polymerization on the rate of polymerization shrinkage and cuspal deflection in composite resins. The linear polymerization shrinkage of each composite was measured using the custom-made linometer along with the light shutter specially devised to block the light at the previously determined interval. Samples were divided into 4 groups by light curing method; Group 1) continuous light (60s with light on); Group 2) intermittent light (cycles of 3s with 2s light on & 1s with light off for 90s): Group 3) intermittent light (cycles of 2s with 1s light on & 1s with light off for 120s); Group 4) intermittent light (cycles of 3s with 1s light on & 2s with light off for 180s). The amount of linear polymerization shrinkage was measured and its maximum rate (Rmax) and peak time (PT) in the first 15 seconds were calculated. For the measurement of cuspal deflection of teeth, MOD cavities were prepared in 10 extracted maxillary premolars. Reduction in the intercuspal distance was measured by the custom-made cuspal deflection measuring machine. ANOVA analysis was used for the comparison of the light curing groups and t-test was used to determine significant difference between the composite resins. Pyramid showed the greater amount of polymerization shrinkage than Heliomolar (p < 0.05). There was no significant difference in the linear polymerization shrinkage among the groups. The Rmax was group 4 < 3, 2 < 1 in Heliomolar and group 3 < 4 < 2, 1 in Pyramid (p < 0.05). Pyramid demonstrated greater cuspal deflection than Heliomolar. The cuspal deflection in Heliomolar was group 4 < 3 < 2, 1 and group 4, 3 < 2, 1 in Pyramid (p < 0.05). It was concluded that the reduced rate of polymerization shrinkage by intermittent polymerization can help to decrease the cuspal deflection.

• Journal of Embryo Transfer
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• v.31 no.1
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• pp.47-52
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• 2016

The objective of this study was to investigate the result of in vivo embryo collection and pregnancy rate after embryo transfer using sex-sorted sperm of Korean brindle cattle. Donor Korean brindle cattle superovulation treated by decreasing dose of FSH injection. Embryos were recovered on 7 days after the third artificial insemination. Control group semen straw used artificial insemination contained 20 million sperm. Sex-sorted semen straws contained 4 million sperm or 10 million sperm. As for the result of the recovery of the in vivo embryos derived from sex-sorted sperm, the number of transferable embryos was significantly highly recovered to be $6.20{\pm}2.28/donor$ from the control group and was significantly lowly recovered to be $1.57{\pm}1.72/donor$ from the group treated at a sperm concentration of $10{\times}10^6$ (p<0.05). The number of unfertilized embryo was $0.8{\pm}1.30/donor$ in control group which was significantly lower than the group treated at a sperm concentration of $4{\times}10^6$ (p<0.05). However, there was no significant difference in the number of undeveloped ova between control and treatment groups. Pregnancy rate after embryo transfer was shown to be 35.00% in control group and 12.50% in treatment group. The karyotype analysis of the calf derived from sex-sorted sperm resulted in a similar chromosomal distribution pattern (2n=60, XX) compared to those of common Korean native cattle.