• 한국토양비료학회지
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• 제32권2호
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• pp.95-108
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• 1999

충북 진천, 음성, 괴산, 중원군과 충남 천원군, 그리고 경북 청도, 성주, 안동군에 분포하는 101개 연초 경작지에 대하여 토양의 화학성 및 토양도 자료들을 이용한 토양 비옥도를 평가하기 위하여 1985년부터 2년 동안포장시험이 수행되었으며 또한 동일 토양에 대한 포트시험도 병행하여 서로 비교하였다. 무비구의 연초 수량을 토양 비옥도 요인으로 고려하여 9개 화학성과 10개 토양도 자료들을 포함하는 19개 독려변수들로 평가하였다. 19개 독립변수들은 11개의 정량적 지표들과 9개의 정성적 지표들로 구분하여 BAS의 REO와 CLM model로 다중선형 회귀분석을 수행하였다. 무비구 연초 수량은 최저치와 최고치 간에 포트시험의 경우 5.0-5.5배, 포장시험의 경우 8.2-14.9배의 차이를 보여 공시토양의 다양한 비옥도 특성을 나타냈다. 무비구 수량과 밀접한 상관을 보인 화학적 지표는 포장시험과 포트시험간뿐 아니라 년차 간에도 상이하였으며, 또한 포장시험의 무비구 수량에 기여하는 정량적 지표들의 표준화 편회귀계수는 모두 1.0 미만을 보여 비옥도 평가를 위한 탄일 유효도지표의 선발이 어렵다는 것을 시사하였다. 비옥도에 대한 독립변수들의 다중선형회귀 평가는 단일 지표에 의한 평가보다 매우 양호하였으며 화학적 지표들 이외에 토양도의 정량적 및 정성적 지표들을 평가에 포함시킴에 따라 결정계수($R^2$)는 점진적으로 증가되었다. 즉 예를 들면 1985년도 무비구 수량에 대한 다중선형회귀의 결정계수는 단일지표 $NO_3-N$ 함량에 의한 평가 0.244에 비하여 화학적 지표들에 의한 평가는 0.422, 토양도의 정량적 지표들의 추가되면 0.503, 그리고 정성적 지표들을 추가하면 0.633으로 증가되었다. 따라서 토양 화학성 이외에 토양도 자료들을 포함하는 정량적 및 정성적 지표들에 의한 다중선형회귀 분석방법은 연초 경작지의 비옥도 평가를 위한 유의성 있는 모델로 추정되었다.

• Clinical and Experimental Reproductive Medicine
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• 제37권2호
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• pp.143-151
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• 2010

목 적: 본 연구는 체외수정술 후 배양 3일째 2개의 난할단계 배아 (D3ET)와 배양 5일째 2개의 포배기단계 배아(D5ET)를 이식했을 때 각각의 임신예후를 비교하기 위하여 시행하였다. 연구방법: 2007년 1월부터 2009년 6월까지 강남차병원 여성의학연구소에서 체외수정술 후 D3ET을 시행한 90명의 환자를 나이와 체외수정 주기의 특성을 고려하여 D5ET군 90명과 비교한 후향적 환자군-대조군 연구를 시행하였으며, 두 군 모두 2개씩의 양질의 배아를 이식하였다. 각각의 임신율, 착상률, 다태임신율을 비교하였다. 결 과: 환자의 특성, 체외수정주기 및 배아의 특징은 두 군 간에 차이를 보이지 않았다. 임신예후를 비교했을 때, D3ET군과 D5ET군 모두 유의한 차이를 보이지 않았다: 착상률 (39.4% vs. 32.8%), 임신율 (57.8% vs. 46.7%), 임상적임신율 (53.3% vs. 45.6%), 진행임신율 (50.0% vs. 42.2%), 유산율 (13.5% vs. 9.5%). 두 군 모두 높은 다태임신율을 보여주었다 (37.5% vs. 34.1%). 결 론: 체외수정술 후 배양 5일째 포배기단계 배아이식이 배양 3일째 난할단계 이식보다 더 좋은 임신예후를 보여주지 못한다. 또한 나이가 젊고, 양질의 배아를 가진 좋은 예후를 예측할 수 있는 여성에서는 다태임신율을 줄이기 위해 단일배아이식을 고려해야 한다.

• 한국인구학
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• 제16권2호
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• pp.125-139
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• 1993

Korea has successfully achieved a lowered fertility level owing to the strong population control policy and effective family planning program. Along with fertility decline and decreased number of children in family, average number of household members has decreased and nontraditional households such as one person household and households composed of unrelated individuals have prolifirated, even though the absolute number of them are found minimal in Korea. However in recent years several data and survey results suggest that one person households are gradually in the increasing trend. The study aimed at investigating the real state of one person households in Korea and next analyzing the proportional distribution of one person households by a few socioeconomic characteristics, thus providing basic for eatablishing far-singhted population and social welfare policy in the future. Korea has experienced high growth rate of economy through government-led development plans starting from the 1960s. During the past three decades, Korea has shifted from the agricultural state to the industrialized one. In compliance with the economic growth, urbanization and industrialization have brought about rural-to-urban migration and a great bulk of young population migrated to urban areas, who are seeking for educational and job opportunities. Korean society has also been under drastic change in every aspect of life involving norms, tradition, and attitude, etc. Therefore, in spite of the prejudice on 'living alone' still remaining, young people gradually leave parents and home, and further form nontraditional households in urban areas. Current increase in the number of one person households is partly attributable to the increase in high female educational attainment and female participation in economic activities. As the industrial structure in Korea changes from primary into secondary and tertiary industries, job opportunities for service/sales and manufacturing are opened to young female labor force in the process of industrialization. Contrary to the formation of one person households by young people, the aged single households are composed when children in family leave one by one because of marriage, education, employment. In particular, a higher proportion of aged female single households occur in rural areas due to the mortality difference by sex. Based on the data released form the 1990 Population and Housing Census and National Fertility and Family Health Survey in 1985 and 1991, the study tried to examine the state of one person households in Korea. According to Census data, the number of one person households increased to 1, 021, 000 in 1990, comprising 9.0 percent of total households. And the survey reveal that among total 11, 540 households, 8.0 percent, 923 households, are composed of one person households. Generally, the proportion of female single households is greater than that of male ones, and a big proportion of one person households is concentrated in the 25-34 age bracket in urban areas and 65 years and more in rural areas. It is shown than one person householders in urban areas have higher educational attainment with 59.2 percent high schooling and over in 1991, Job seeking proved to be the main reason for leaving home and forming one person households. The number of young female single households with higher education and economic self-reliance are found nil and the study did not allow to analyze the causal realtionship between female education and employment and one person household formation. However more research and deep analysis on the causal facors on one person household formation using statistical method are believed to be necessary.

• Clinical and Experimental Reproductive Medicine
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• 제32권2호
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• pp.91-99
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• 2005

Objective: To define an appropriate vitrification condition of preantral follicle that yields high survival and to evaluate growth and ovulation rate of mouse follicles during in vitro culture after vitrification. Methods: Preantral follicles were isolated mechanically from mouse ovaries that were surgically recovered from mice aged 14 days. Retrieved preantral follicles were placed in EG (Ethylene Glycol) for 2, 5, 10 minutes and transferred to EFS-40 (40% EG, 18% Ficoll-70, 0.5 M sucrose) for 0.5, 1, 2 minutes. And then, preantral follicles were placed onto an EM grid and submerged immediately in liquid nitrogen. Thawing was carried out at room temperature. After defining the most appropriate vitrification condition that yields high survival, in vitro growth and ovulation rate of follicles were evaluated. Results: Appropriate vitrification condition that yield high survival rate ($83.2{\pm}2.1%$) of preantral follicle was EG for 5 minutes and EFS-40 for 0.5 minutes. In vitro survival rate of the vitrified preantral follicles were $85.5{\pm}0.5%$, $67.9{\pm}0.8%$ and $40.2{\pm}0.5%$ on day 2, 6 and 10. And in vitro growth of the vitrified preantral follicles were $107.1{\pm}16.1{\mu}m$, $117.1{\pm}18.4{\mu}m$, $178.4{\pm}45.6{\mu}m$ and $325.4{\pm}54.4{\mu}m$ on day 0, 2, 6 and 10. Although in vitro survival rate and growth of vitrified preantral follicles were lower than that of non-vitrified preantral follicles, the patterns of survival and growth were similar in vitrified and non-vitrified preantral follicles. The ovulation rate of antral follicles that was grown from vitrified preantral follicles was $32.6{\pm}1.2%$. Conclusion: Vitrified preantral follicles could be grown to antral sizes, and mature oocytes that can be used for IVF-ET programs were produced successfully. These data suggest that cryopreservation of preantral follicle by vitrification can be used for the preservation of the fertility.

• 한국발생생물학회지:발생과생식
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• 제16권4호
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• pp.379-384
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• 2012

Lhx8 (LIM homeobox 8) gene encodes a LIM homeodomain transcriptional regulator that is preferentially expressed in germ cells and critical for mammalian folliculogenesis. However, Lhx8 DNA binding sequences are not characterized yet. We aimed to identify and characterize a cis-acting sequence of germ-cell specific transcriptional factor, Lhx8. To identify Lhx8 DNA binding element, Cyclic Amplification of Sequence Target (CAST) Analysis was performed. Electrophoretic Mobility Shift Assay (EMSA) was processed for the binding specificity of Lhx8. Luciferase assay was for the transcriptional activity of Lhx8 through identified DNA binding site. We identified a putative cis-acting sequence, TGATTG as Lhx8 DNA binding element (LBE). In addition, Lhx8 binds to the LBE with high affinity and augments transcriptional activity of luciferase reporter driven by artificial promoter containing the Lhx8 binding element. These findings indicate that Lhx8 directly regulates the transcription of genes containing Lhx8 binding element in oocytes during early folliculogenesis.

• Clinical and Experimental Pediatrics
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• 제54권11호
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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.

• Animal cells and systems
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• 제13권2호
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• pp.205-212
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• 2009

Known as a female hormone, estrogen, performs important functions, and the activities of the hormone are mediated via the estrogen receptor. The principal objective of the present study was to assess the effects of a estrogen receptor agonist in male reproductive organs. In this study, the estrogen receptor alpha agonist, PPT, was injected subcutaneously into adult male mice. The effects of PPT on the murine reproductive system were histologically assessed at 3,5, and 8 weeks after treatment. In the treatment group, reductions were observed in the weight of the body, testis and epididymis. Microscopic examination revealed a reduction in seminiferous tubular diameter in the testis, and epithelial cell height in the epididymis during the experiment. 8 weeks after treatment, spermatogenesis was not detected, nor was the lumen of the seminiferous tubules. In the fertility test, 1 week after PPT injection, the fertilizing ability of males was decreased, and on the 2nd and 3rd weeks, complete infertility was observed. In conclusion, the injection of high concentrations of PPT into adult males induced physiological changes, including infertility, and also induced morphological changes, including a reduction in the height of epithelial cells within the reproductive system.

• Clinical and Experimental Reproductive Medicine
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• 제47권2호
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• pp.94-100
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• 2020

The inverse correlation between maternal age and pregnancy rate represents a major challenge for reproductive endocrinology. The high embryo ploidy error rate in failed in vitro fertilization (IVF) cycles reflects genetic misfires accumulated by older oocytes over time. Despite the application of different follicular recruitment protocols during IVF, gonadotropin modifications are generally futile in addressing such damage. Even when additional oocytes are retrieved, quality is frequently poor. Older oocytes with serious cytoplasmic and/or chromosomal errors are often harvested from poorly perfused follicles, and ovarian vascularity and follicular oxygenation impact embryonic chromosomal competency. Because stimulation regimens exert their effects briefly and immediately before ovulation, gonadotropins alone are an ineffective antidote to long-term hypoxic pathology. In contrast, the tissue repair properties (and particularly the angiogenic effects) of platelet-rich plasma (PRP) are well known, with applications in other clinical contexts. Injection of conventional PRP and/or its components (e.g., isolated platelet-derived growth factors as a cell-free substrate) into ovarian tissue prior to IVF has been reported to improve reproductive outcomes. Any derivative neovascularity may modulate oocyte competence by increasing cellular oxygenation and/or lowering concentrations of intraovarian reactive oxygen species. We propose a mechanism to support intrastromal angiogenesis, improved follicular perfusion, and, crucially, embryo ploidy rescue. This last effect may be explained by mRNA upregulation coordinated by PRP-associated molecular signaling, as in other tissue systems. Additionally, we outline an intraovarian injection technique for platelet-derived growth factors and present this method to help minimize reliance on donor oocytes and conventional hormone replacement therapy.

• The Plant Pathology Journal
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• 제35권4호
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• pp.301-312
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• 2019

Sorghum is the fifth most important cereal worldwide, spreading from Africa throughout the world. It is particularly important in the semi-arid tropics due to its drought tolerance, and when cultivated in Southeast Asia commonly occurs as a second crop during the dry season. We recovered Fusarium from sorghum in Thailand and found F. proliferatum, F. thapsinum and F. verticillioides most frequently, and intermittent isolates of F. sacchari and F. beomiforme. The relatively high frequencies of F. proliferatum and F. verticillioides, suggest mycotoxin contamination, particularly fumonisins and moniliformin, should be evaluated. Genetic variation within the three commonly recovered species was characterized with vegetative compatibility, mating type, Amplified Fragment Length Polymorphisms (AFLPs), and female fertility. Effective population number ($N_e$) was highest for F. verticillioides and lowest for F. thapsinum with values based on mating type allele frequencies higher than those based on female fertility. Based on AFLP genetic variation, the F. thapsinum populations were the most closely related, the F. verticillioides populations were the most distantly related, and the F. proliferatum populations were in an intermediate position. The genetic variation observed could result if F. thapsinum is introduced primarily with seed, while F. proliferatum and F. verticillioides could arrive with seed or be carried over from previous crops, e.g., rice or maize, which sorghum is following. Confirmation of species transmission patterns is needed to understand the agricultural systems in which sorghum is grown in Southeast Asia, which are quite different from the systems found in Africa, Australia, India and the Americas.

• 동남아시아연구
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• 제20권3호
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• pp.147-182
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• 2010

The purpose of this study is to examine the population changes in the nine Southeast Asian countries, including Cambodia, Lao People's Democratic Republic, Philippine, Indonesia, Malaysia, Myanmar, Singapore, Vietnam, and Thailand. According to the demographic transition theory which described the transition from high birth and death rates to low birth and death rates, the demographic changes in less developed countries, including the Southeast Asian countries, follow the general pattern of the population changes that the Western countries had experienced. However, this theory does not consider the fact that the demographic behaviors such as fertility and mortality tend to be ethnocentric (or particular). Therefore, I examine in this paper both the generality and particularity of the population changes in the Southeast Asia . The analytic results are consistent with my assumptions. Every country in the Southeast Asia will soon reach the third phrase of the demographic transition and meet population ageing process. However, the timings arriving at the third phrase can differ. Singapore which is the most developed country had firstly passed through the demographic transition and the highest level of population ageing. Cambodia and Lao People's Democratic Republic, the least developed countries, will lastly arrive at the third phrase and the ageing society. In addition, among the three countries which had experienced war or civil war, only Cambodia had experienced babyboom.