• Clinical and Experimental Reproductive Medicine
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• v.47 no.2
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• pp.114-121
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• 2020

Objective: Despite extensive research on implantation failure, little is known about the molecular mechanisms underlying the crosstalk between the embryo and the maternal endometrium, which is critical for successful pregnancy. Profilin 1 (PFN1), which is expressed both in the embryo and in the endometrial epithelium, acts as a potent regulator of actin polymerization and the cytoskeletal network. In this study, we identified the specific role of endometrial PFN1 during embryo implantation. Methods: Morphological alterations depending on the status of PFN1 expression were assessed in PFN1-depleted or control cells grown on Matrigel-coated cover glass. Day-5 mouse embryos were cocultured with Ishikawa cells. Comparisons of the rates of F-actin formation and embryo attachment were performed by measuring the stability of the attached embryo onto PFN1-depleted or control cells. Results: Depletion of PFN1 in endometrial epithelial cells induced a significant reduction in cell-cell adhesion displaying less formation of colonies and a more circular cell shape. Mouse embryos co-cultured with PFN1-depleted cells failed to form actin cytoskeletal networks, whereas more F-actin formation in the direction of surrounding PFN1-intact endometrial epithelial cells was detected. Furthermore, significantly lower embryo attachment stability was observed in PFN1-depleted cells than in control cells. This may have been due to reduced endometrial receptivity caused by impaired actin cytoskeletal networks associated with PFN1 deficiency. Conclusion: These observations definitively demonstrate an important role of PFN1 in mediating cell-cell adhesion during the initial stage of embryo implantation and suggest a potential therapeutic target or novel biomarker for patients suffering from implantation failure.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.4
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• pp.232-238
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• 2017

Objective: To determine whether reducing the cetrorelix dose in the antagonist protocol to 0.125 mg had any deleterious effects on follicular development, the number and quality of retrieved oocytes, or the number of embryos, and to characterize its effects on the affordability of assisted reproductive technology. Methods: This randomized controlled study was conducted at the Fertility Unit of Tanta Educational Hospital of Tanta University, the Egyptian Consultants' Fertility Center, and the Qurrat Aien Fertility Center, from January 1 to June 30, 2017. Patients' demographic data, stimulation protocol, costs, pregnancy rate, and complications were recorded. Patients were randomly allocated into two groups: group I (n = 61) received 0.125 mg of cetrorelix (the study group), and group II (n = 62) received 0.25 mg of cetrorelix (the control group). Results: The demographic data were comparable regarding age, parity, duration of infertility, and body mass index. The dose of recombinant follicle-stimulating hormone units required was $2,350.43{\pm}150.76$ IU in group I and $2,366.25{\pm}140.34$ IU in group II, which was not a significant difference (p= 0.548). The duration of stimulation, number of retrieved oocytes, and number of developed embryos were not significantly different between the groups. The clinical and ongoing pregnancy rates likewise did not significantly differ. The cost of intracytoplasmic sperm injection per cycle was significantly lower in group I than in group II (US $ $494.66{\pm}4.079$ vs. US $ $649.677{\pm}43.637$). Conclusion: Reduction of the cetrorelix dose in the antagonist protocol was not associated with any significant difference either in the number of oocytes retrieved or in the pregnancy rate. Moreover, it was more economically feasible for patients in a low-resource country.

• Development and Reproduction
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• v.17 no.1
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• pp.63-72
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• 2013

A specific inhibitor of RNA polymerase II, ${\alpha}$-amanitin is broadly used to block transcriptional activities in cells. Previous studies showed that ${\alpha}$-amanitin affects in vitro maturation of cumulus-oocyte-complex (COC). In this study, we evaluated the target of ${\alpha}$-amanitin, and whether it affects oocytes or cumulus cells (CCs), or both. We treated ${\alpha}$-amanitin with different time period during in vitro culture of denuded oocytes (DOs) or COCs in comparison, and observed the changes in morphology and maturation status. Although DOs did not show any change in morphology and maturation rates with ${\alpha}$-amanitin treatment, oocytes from COCs were arrested at metaphase I (MI) stage and CCs were more scattered than control groups. To discover causes of meiotic arrest and scattering of CCs, we focused on changes of cumulus expansion, gap junctions, and cellular metabolism which to be the important factors for the successful in vitro maturation of COCs. Expression of genes for cumulus expansion markers (Ptx3, Has2, and Tnfaip6) and gap junctional proteins (Gja1, Gja4, and Gjc1) decreased in ${\alpha}$-amanitin-treated CCs. However, these changes were not observed in oocytes. In addition, expression of genes related to metabolism (Prps1, Rpe, Rpia, Taldo1, and Tkt) decreased in ${\alpha}$-amanitin-treated CCs but not in oocytes. Therefore, we concluded that the transcriptional activities of CCs for supporting suitable transcripts, especially for its metabolic activities and formation of gap junctions among CCs as well as with oocytes, are important for oocytes maturation in COCs.

• Korean Journal of Childcare and Education
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• v.16 no.4
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• pp.1-29
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• 2020

Objective: The present study aimed to explore the experiences of mothers who have abandoned their additional birth plans since their first child was born. Methods: During in-depth interviews, mothers were asked to recall their own experiences of motherhood. The interview data were analyzed using the grounded theory. Results: The central phenomenon was 'The burden of raising a child is too heavy for mothers to carry alone.' The causal conditions were 'First experience: Unpredictable life', 'Physical and psychological difficulty', and 'Spouse's absence.' The contextual conditions were 'Expectations and reality of parenting' and 'Workplace conditions.' The mothers used interaction strategies of 'Defusing conflict only on a surface level: Giving up', 'Reliance on grandmothers', and 'Downgrading career aspirations.' These strategies were mediated by intervening conditions, 'Stereotypes and experiences of non-family nanny', 'Child's development', and 'Family conflict.' The results were 'Endless guilt', 'Ambivalence between independence versus interdependence' and 'Unfairness: Why only me?' Finally, the process of psychological conflict was identified to account for the steps leading mothers to give up on their birth plans. Conclusion/Implications: During the first experience of motherhood, mothers' conflict gets escalated despite their struggles. These experiences might discourage their additional birth plans. These results provide implications for policies to increase fertility rates.

• The Korean Journal of Ecology
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• v.27 no.4
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• pp.217-224
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• 2004

The purpose of this study is to clarify the effects of the conversion of the forest management type from a natural deciduous broad-leaved forest to an artificial evergreen coniferous forest based on organic matter dynamics. We investigated the amounts and carbon contents of the forest floor and the litterfall, soil chemical characteristics and cellulose decomposition rates in the natural deciduous broad-leaved forest and adjacent artificial evergreen coniferous forest. In the artificial evergreen coniferous forest were planted Japanese cypress (Chamaecyparis obtusa) on the upper slope and Japanese cedar (Cryptomeria japonica) on the lower slope. The soil carbon and nitrogen contents, CEC and microbial activity had decreased due to the conversion of the forest management type from a natural deciduous broad-leaved forest to an artificial Japanese cypress forest, and were almost the same for the conversion to a Japanese cedar forest. Under the same conditions, it is considered that the soil fertility was different by planting specific tree species because the organic matter dynamics were changed by them.

• Clinical and Experimental Pediatrics
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• v.54 no.11
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• pp.429-435
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• 2011

Although Korean population has been growing steadily during the past four decades, the nation is rapidly becoming an aging society because of its declining birth rate combined with an increasing life expectancy. In addition, Korea has one of the lowest fertility rates in the world due to fewer married couples, advanced maternal age, and falling birth rate. The prevalence of low birth weight infants and multiple births has been increased compared with the decrease in the birth rate. Moreover, the number of congenital anomalies is expected to increase due to the advanced maternal age. In addition, the number of interracial children is expected to increase due to the rise in the number of international marriages. However, the maternal education level is high, single-mother birth rate is low, and the gender imbalance has lessened. The number of overweight babies has been decreased, as more pregnant women are receiving adequate prenatal care. Compared to the Asian average birth weight, the average birth weight is the highest in Asia. Moreover, the rate of low birth weight infants is low, and infant mortality is similarly low across Asia. Using birth data from Statistics Korea and studies of birth outcomes in Korea and abroad, this study aimed to assess the changes in maternal and infant characteristics associated with birth outcomes during the past four decades and identify necessary information infrastructures to study countermeasures the decrease in birth rate and increase in low birth weight infants in Korea.

• Korea journal of population studies
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• v.30 no.3
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• pp.1-31
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• 2007

Korea, China and Japan have been undergoing economic development, demographic transition and population aging, in a speed unparalleled in world history. This paper examines, for each of these countries, on (i) the trend and prospect of the effective dependency burden (EDB) in terms of stable population and (ii) the optimum fertility path which will lead to a stable population with the minimum level of EDB under the trend and prospect of decreasing age specific mortality rates. It then evaluates (iii) the transitory EDB costs of pro-natal policies during the adjustment process of stabilization and (iv) the effectiveness of other supplementary policies which influence EDB parameters.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.447-447
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• 2023

Soil organic carbon (SOC) is a critical indicator of soil fertility. Its importance in maintaining ecological balance has received widespread attention. However, global temperatures have risen by 0.8℃ since the late 1800s due to human-induced greenhouse gas emissions, resulting in severe disruptions in SOC dynamics. To study the impacts of temperature variations on SOC and soil respiration, we used the Soil Carbon and Landscape co-Evolution (SCALE) model, which was capable of estimating the spatial distribution of soil carbon dynamics. The study site was located at Heshan Farm (125°20'10.5"E, 49°00'23.1"N), Nenjiang County in Heilongjiang Province, Northeast China. We validated the model using observed soil organic carbon and soil respiration in 2015 and achieved excellent agreement between observed and modeled variables. Our results showed considerable influences of temperature increases on SOC and soil respiration rates at both erosion and deposition areas. In particular, changes in SOC and soil respiration at the deposition area were greater than at the erosion area. Our study highlights that the impacts of temperature elevations are considerably dependent on soil erosion and deposition processes. Thus, it is important to implement effective soil conservation strategies to maintain soil fertility under global warming.

• Journal of Families and Better Life
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• v.28 no.2
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• pp.89-96
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• 2010

This study examines how frequently employers offer family-friendly corporate programs and how frequently employees use the programs. This study also seeks to discover whether the implementation and utilization of family-friendly corporate programs results in an increase in employees' childbirths. Data were collected from 377 married full-time employees working in private sector companies located in Seoul and GyeongGi-Do. Frequency analyses of the employees' responses showed moderate rates of implementation of family-friendly corporate programs and much lower rates of employees' utilization. The hierarchical regression analysis revealed that the implementation of family-friendly corporate programs significantly predicted employees' childbirths. However, this was ineffective, having no significant influence on employees' childbirths, when their utilization of the programs was entered into the model. Higher rates of utilization of family-friendly corporate programs predicted more childbirths after employment. This study suggests that the implementation of family-friendly corporate programs per se is not a complete solution to get employees to have more babies. Rather, what matters is the usability of those programs. Finally, the implications of the study results are discussed.

• Korean Journal of Animal Reproduction
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• v.16 no.1
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• pp.63-76
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• 1992

This study was carried out to investigate the appearance time of the second polar body for producing Gynogenesis or Triploid which could be obtained by arresting the second polar body by cold shock, and then blastoderm was used to measure fertility that revealed the nature of oogenesis, the effects of water temperature on fertility, hatchability, abnormality, viability and growth rate, and the water temperature and the breeding methods to prevent early death of larvae in Korean loach(Misgurnus anguillicaudatus) ; the results obtained in this study were summarized as follows. The second polar body was observed ont he surface of plasma disc close to micropyle within 10~40 min after fertilization at 29$^{\circ}C$. Artificial inseminatin had to be done immediately after the egg spawning because the spermatozoa of loach their mobility within 2 minutes when they were exposed to water. The amount of time needed to reach at blastoderm stage was 12 hours if fertilized eggs were incubated at 16$^{\circ}C$, 8 hours at 19$^{\circ}C$, 6 hours at 21$^{\circ}C$, 5 hours at 23$^{\circ}C$, 4 hours at 26$^{\circ}C$ and 3 hours 30 min at 29$^{\circ}C$ showing the shorter time for development of eggs at higher temperature. Fertilization rates in water temperatures of 19$^{\circ}C$, 21$^{\circ}C$, 23$^{\circ}C$, and 26$^{\circ}C$ were higher than those of water temperatures, 16$^{\circ}C$ and 29$^{\circ}C$. Water temperatures at 19$^{\circ}C$, 21$^{\circ}C$, and 23$^{\circ}C$ showed higher hatching rates that those of 16$^{\circ}C$, 26$^{\circ}C$, and 29$^{\circ}C$, while abnormal rates in 16$^{\circ}C$, 19$^{\circ}C$, 21$^{\circ}C$ and 23$^{\circ}C$ were lower than that of 26$^{\circ}C$ and 29$^{\circ}C$. Water temperatures at 16$^{\circ}C$, 19$^{\circ}C$, 21$^{\circ}C$, 23$^{\circ}C$ and 26$^{\circ}C$ respectively, were more different than 29$^{\circ}C$ in survival rates. The embryos were hatched at 72 hours after fertilization in 16$^{\circ}C$ water temperature, 48 hours in 19$^{\circ}C$, 40 hours in 21$^{\circ}C$, 32 hours in 23$^{\circ}C$, 25 hours in 26$^{\circ}C$, and 16 hours in 29$^{\circ}C$. Within three days after hatched out, the larvage grew 3mm in total length, the yolk granules were entirely consumed and the head and the trunk became thicker. Within 45 days after hatched out, the larva grew 25mm at 29$^{\circ}C$, 21mm at 26$^{\circ}C$, 16mm at 23$^{\circ}C$, 15mm at 21$^{\circ}C$, 12mm at 16$^{\circ}C$ in a 30 litreglass aquarium.