• Korean Journal of Culture and Social Issue
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• v.18 no.1
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• pp.97-110
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• 2012

The sharp decline of fertility in industrialized countries since the 19th century constitutes a major problem for evolutionary approaches to human behavior. Why would people voluntarily reduce their total number of offspring, despite the fact that resources are so abundant in modern times? Here I review three evolutionary hypotheses for low fertility in modern societies, and discuss how the evolutionary perspective could shed new light on solving the problem of low fertility in Korea. Low fertility may be 1) a maladaptive outcome from the mismatch between our ancestral environments and evolutionarily novel environments, 2) a consequence of gene-culture coevolution where traits that reduce genetic fitness can still spread through a population as a result of imitation, especially if the traits are expressed by high-status people, or 3) an adaptation that maximize parents' long-term genetic fitness in knowledge-based industrialized societies where high parental investment is required for rearing competitive offspring. Based on these considerations, I suggest how the evolutionary explanations of low fertility can be applied to increasing the birth rate in Korea.

• Journal of Preventive Medicine and Public Health
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• v.56 no.6
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• pp.533-541
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• 2023

Objectives: This study analyzed the relationship between parental body mass index (BMI; BMI_p) and hypertension in their adolescent offspring (HTN_a), focusing on the mediating effect of adolescents' BMI (BMI_a). Methods: Utilizing data from the Korea National Health and Nutrition Examination Survey, including participants aged 12-18, we conducted a mediation analysis while controlling for confounding factors such as age, sex, physical activity, dietary habits, household income quartile, and parents' alcohol and smoking habits. Results: The study included a total of 5731 participants, of whom 3381 and 5455 participants had data on fathers' and mothers' BMI, respectively. For adolescent systolic blood pressure (SBP_a), the father's BMI (BMI_f) had a significant total effect (β, 0.23; 95% confidence interval [CI], 0.12 to 0.34) and average controlled mediated effect (ACME) (β, 0.27; 95% CI, 0.23 to 0.32), but the average direct effect (ADE) was not significant. The mother's BMI (BMI_m) had a significant total effect (β, 0.17; 95% CI, 0.09 to 0.25), ACME (β, 0.25; 95% CI, 0.22 to 0.28) and ADE (β, -0.08; 95% CI, -0.16 to 0.00). For adolescent diastolic blood pressure, both BMI_f and BMI_m had significant ACMEs (β, 0.10; 95% CI, 0.08 to 0.12 and β, 0.09; 95% CI, 0.07 to 0.12, respectively), BMI_m had a significant ADE (β, -0.09; 95% CI, -0.16 to -0.02) but BMI_f had an insignificant ADE and total effect. Conclusions: The study found that parental BMI had a significant effect on SBP_a, mediated through BMI_a. Therefore, a high BMI in parents could be a risk factor, mediated through BMI_a, for systolic hypertension in adolescents, necessitating appropriate management.

• Journal of Animal Science and Technology
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• v.66 no.5
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• pp.920-935
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• 2024

Embryo transfer plays a crucial role in enhancing the breeding value of livestock; it has been applied in Hanwoo cattle, which is a popular breed for beef production in Korea. Both in vivo-derived (IVD) and in vitro-produced (IVP) embryos are used for this purpose; however, IVP embryos have been preferred recently owing to advancements in ovum pick-up (OPU) technology and genomic selection. Despite technological advancements, comprehensive data on large-scale OPU/IVEP/embryo transfer in Hanwoo cows are lacking. In this study, 16 elite Hanwoo donor cows were selected on the basis of specific criteria. Oocytes were retrieved from 241 cows using OPU. The collected cumulus-oocyte complexes (COCs) were matured, fertilized, and cultured in vitro to produce transferable embryos. Embryos were classified according to their developmental stage and then transferred to 675 recipient cows. A total of 3,317 COCs were collected, with an average of 13.76 COCs per cow. The number of transferable embryos produced per cow was 3.7. Hanwoo OPU-derived IVP embryos exhibited a higher production yield than the global average, indicating a stable IVEP environment. Both fresh and frozen IVP embryos yielded similar conception rates; hence, the use of vitrified-thawed embryos in transfer plans feasible. However, frozen-thawed embryos at Stage 7 had a lower conception rate than those at earlier stages. There was no significant difference between the conception rates of sexually mature heifers and postpartum cows used as recipients. The male-to-female offspring ratio increased as the developmental stage progressed. Seasonal effects on conception rates were not observed; however, higher abortion rates and a higher proportion of male offspring were observed during winter. This study provides valuable data for the Korean embryo transfer industry, enabling more strategic growth of the domestic Hanwoo embryo industry.

• Anatomy and Cell Biology
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• v.57 no.3
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• pp.400-407
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• 2024

Intrauterine alcohol exposure delays bone maturation and intensifies osteoporosis and fracture risk. As most studies emphasize the neurological aspects of intrauterine alcohol exposure, there is a lack of research on the implications pertaining to osseous tissue. Previous studies investigated these effects in fetuses, with limited studies on postnatal life. Postnatal studies are crucial since peak bone growth occurs during adolescence. This study aimed at assessing the effects of prenatal alcohol exposure on the humerus proximal and distal growth plate chondrocytes in 3-week-old rats. Sprague Dawley rats (n=9) were assigned to either the ethanol group (n=3), saline (n=3), and untreated (n=3) group and time-mated. Once pregnant, as confirmed by the presence of a copulation plug, the former 2 groups were treated with 0.015 ml/g of 25.2% ethanol and 0.9% saline. The untreated group received no treatment. The left humeri belonging to 6 pups per group were used. Serial sections were cut with a microtome at 5 ㎛ thickness. These sections were stained with haematoxylin and eosin for assessment of normal morphology or immunolabeled with anti-Ki-67 and transforming growth factor β-1 (TGFβ-1) antibody. Prenatal alcohol exposure adversely effected the growth plate sizes and the number of cells in the proliferative zone. Fewer TGFβ-1 immunopositive and proliferative chondrocytes were found using the anti-Ki-67 antibody. This may explain the growth retardation in offspring exposed to gestational alcohol, showing that gestational alcohol exposure inhibits cell proliferation, aiding the diminished stature.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.1
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• pp.28-39
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• 2017

Persistent organic pollutants (POPs) can affect epigenetic mechanisms and obesity development. Polybrominated diphenyl ethers (PBDEs)-widely used to make flames-are one of the important POPs. Prenatal exposure to endocrine disrupting chemicals (EDCs), such as POPs, may affect global DNA methylation in long interspersed nuclear elements (LINE-1), increasing the risk of obesity later in life. Therefore, pregnant Sprague-Dawley (SD) rats were used to elucidate whether BDE-47 and BDE-209 transferred through placenta and breast milk cause epigenetic changes in LINE-1 and increase genetic susceptibility to obesity as obesogen during the developmental periods. Global DNA methylation in LINE-1 and gene expression related to obesity were measured in dams and offspring, using a methylation-sensitive high resolution melting analysis (MS-HRM) and direct bisulfite sequencing and quantitative real time polymerase chain reaction (qPCR), respectively. The results of MS-HRM showed global DNA hypomethylation patterns in LINE-1 of exposed offspring (2 of total 4) at PND 4, but bisulfite sequencing showed no difference in both the exposed and non-exposed groups. Gene expression in dams related to ${\beta}$-oxidation pathway and those related to adipokines showed different patterns between the two groups. On the contrary, gene expressions of offspring showed a similar pattern. Gene expressions related to ${\beta}$-oxidation pathway and obesity were significantly increased when compared with 'at birth', but not $PPAR-{\alpha}$. In conclusion, this study demonstrated the possibility that co-exposure to BDE-47 and BDE-209-via the placenta and breast milk-may affect epigenetic changes and modulate gene expression levels related to obesity.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.2
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• pp.79-83
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• 2000

A han transfers her serum immunoglobulin G to the agg (IgY) and gives immunity to her offspring. Therefore, The hen agg can be an effective supplier of a large amount of antigen specific antibody that accumulates in the egg yolk. Antigen specific antibody has been widely used for immunological analysis in the field of diagnosis as well as pure scientific research. The production and separation technology of IgY is demonstrated in the present study.

• Journal of Ecology and Environment
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• v.31 no.2
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• pp.97-105
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• 2008

Subsocial behavior of the genus Cryptocercus cockroaches has been believed as primitive traits of termite eusociality. Thus, it has been believed that understanding Cryptocercus subsociality is a pre-requisite stage to infer evolutionary route of the eusociality in termites. Woodroaches of Cryptocercus are also well known because of its peculiar characteristics including adults living monogamously in pairs, semelparous reproduction, xylophagy, obligatory association between adults and their offspring, slow development, and anal trophallaxis by adults. Based on the previously accumulated data, we try to understand two major components of Cryptocercus life history, development and reproduction. We hypothesize that harsh winter and length of winter might be one of the main causes driving the appearance of the delayed development and semelparous reproduction in Cryptocercus life history.

• Toxicological Research
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• v.21 no.2
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• pp.129-134
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• 2005

Styrene is a commercially important chemical used mainly in the production of plastics. A toxic effect exerted by styrene exposure may cause infertility, congenital anomalies or death in offspring. Treatment with styrene for 0, 50, 100, and 500 mg/kg for 5 days in Sprague-Dawley rats significantly decreased sperm motilities and sperm counts while sperm abnormalities were significantly increased. To determine the relationship between changes in sperm motilities and roles of reactive oxygen species (ROS), we determined the effect of styrene on ROS production and mRNA expression of antioxidant enzymes in rats. ROS production was enhanced by styrene treatment in a dose-dependent manner. The mRNA expression of catalase and superoxide dismutase (SOD) 2 was strongly suppressed by styrene treatment although SOD1 or glutathione peroxidase (GPX) 4 expressions were not significantly changed. Taken together, these results indicate that styrene may cause toxic effect in rat sperm cells by enhancing oxidative stresses.

• Korean Journal of Veterinary Research
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• v.31 no.2
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• pp.229-234
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• 1991

Thc chimeric morulae were produced following aggregation of the half embryos which were microsurgically bisected at 8-cell and early morula stage. Different phenotypic embryos were obtained by mating ICR female mice with ICR or CBA male mice. The early morula stage was thc desirable stage for the aggregation of mouse embryos after bisection. The post-thawed survival rates of bisected-aggregated embryos that developed into normal blastocyst after conventional freezing in DMSO and ethylene glycol were 30.5 and 32.896, respectively. One offspring was produced by transferring the 67 frozen-thawed bisected-aggregated embryos.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2500-2504
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• 2011

Living organisms are composed of cells that can replicate themselves through growth, division packed with tons capacity. On DNA mutations, ie mutations in the offspring's survival and reproduction can be held against you, and packed with tons ambivalence that could benefit. In this study, the DNA double helix is used as a template for replication, we first separated into single strands of the double helix must be opened Combining the double helix portion of the location of errors in the bond provides a way to find and repair.