• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.192-197
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• 2009

This study was conducted to investigate the effect of site-specific variable fertilization following digital fertility map generated from soil analysis on rice growth and yield. The site-specific application of fertilizer was implemented by using rice transplanter equipped with side dressing applicator and global positioning system (GPS). Coefficient of variation (C.V.) of soil nitrogen content was reduced after the experiment, and spatial variation of semivariogram was reduced. Rice growth from tillering to ripening stage, plant height, tiller and panicle number increased at site-specific variable fertilization treatment, and coefficient variation (C.V.) of each growth characteristics was lower than those of conventional fertilization treatment. As a result, fertility in the rice field was more uniform become of site-specific fertilizer application. Head rice yield of site-specific application plot increased by 9% (i.e., to from 450 kg/10a to 492 kg/10a of the control plot) and its CV was significantly reduced to 3.5 compared to 7.8 of the control plot. In addition, there was no significant difference in amylose, protein contents and whiteness of milled rice, but its CV was reduced.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.6
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• pp.525-532
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• 2021

We have investigated the relative roles of α₁-adrenoceptors and purinoceptors in contractions to low and high frequency stimulation of the mouse vas deferens, in terms of the time course of responses. In separate experiments, isometric contractile responses were obtained to 10 pulses at 1 Hz and 40 pulses at 10 Hz. Responses to 1 Hz stimulation consisted of a series of discrete peaks. The α_1A-adrenoceptor antagonist RS100329 (10^-9M-10^-7M) significantly reduced the response to the first pulse, the α_1D-adrenoceptor antagonist BMY7378 (10^-7M-10^-6M) significantly reduced the response to the first two pulses, and the non-selective α₁-adrenoceptor antagonist prazosin (10^-8M) reduced the response to the first 4 pulses at 1 Hz. Responses to 10 Hz stimulation consisted of an early peak response and a maintained plateau response. RS100329 significantly reduced the peak response but did not significantly affect the plateau response. Prazosin, significantly reduced both the peak and plateau responses. The α_1A-adrenoceptor antagonist RS17053 in high concentrations reduced mainly the plateau response leaving a clear early peak response. The plateau response of contraction was almost abolished by the purinoceptor antagonist suramin. These results suggest that there is a relatively minor early α_1D-adrenoceptor and a larger early α_1A-adrenoceptor component to stimulationevoked contractions of mouse vas deferens, but the major α₁-adrenoceptor component is revealed by prazosin to be α_1B-adrenoceptor mediated. α_1B-Adrenoceptor activation probably facilitates contractions mediated by other α₁-adrenoceptors and by purinoceptors. These results suggest that combined non-selective α₁-adrenoceptor blockade, particularly α_1B-adrenoceptor blockade, in addition to P2X1-purinoceptor blockade is useful in reducing male fertility.

• Journal of Families and Better Life
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• v.24 no.6 s.84
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• pp.177-193
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• 2006

This study analyzes marriage and fertility rates in Korea and makes recommendations for family policy. Based on the 'The Report of Marriage & Divorce Statistics in 2005' and data from the Korea Statistical Information System (KOSIS) of the National Statistics Organization, the trends, reasons for marriage rates changes, and future expectations were critically reviewed. In addition, the relationship between marriage and fertility rates was analyzed. The principle characteristics of marriage rates are as follows: 1) the M-shape of the longitudinal crude marriage rates; 2) the increased age of individuals entering their the first marriage; 3) the increase in remarriage rates; 4) the changes in the patterns of remarriage; 5) the increased in the age at which individuals remarry and; 6) the increase in marriage to non-Koreans. The marriage and fertility rates changes are a permanent normative shift because of 1) later marriage because of women's increased education and labor force participation 2) rational choices about birth control 3) reduced population because of the aging of baby boomers 4) structural changes in the marriage market and 5) egalitarian changes in women's attitudes toward marriage and family. The recommendations for future family policy were as follows: 1) the need for a realistic, long-term family policy because the current marriage patterns will continue; 2) the need to develop new statistics such as fertility rates that are based on marriage cohort or birth cohort because family behavior is a mixture of personal, social and political responses; 3) the need for impact analysis of current family policy about increasing fertility rates; 4) the need for a new family perspective that encompasses diverse marriage and family patterns; 5) the need to focus on men's role in families because of women's changing roles and family interaction patterns and; 6) the need for preventive family policies such as family life education.

• Korean Journal of Animal Reproduction
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• v.7 no.2
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• pp.57-71
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• 1983

1. Diluted chicken semen can be preserved at 2 to 5$^{\circ}C$ for 24 to 48 hr with resultant fertility of greater than 90% of that of fresh semen. Turkey semen can be preserved at 10 to 15$^{\circ}C$ for 6 to 24 hr and provide economical fertility. 2. Frozen chicken semen has given variable results; a 21 to 93% fertility ranges as compared to 92 to 94% expected with fresh semen. Highest fertility levels obtained with frozen turkey semen intravaginally inseminated have been 61 and 63% using DMSO and glycerol, respectively, as cryoprotectants. 3. The use of glycerol as a cryoprotectant reauires that its concentration in semen be reduced to less than 2% either by dialysis or centrifugation after thawing and before intravaginal insemination if optimal fertility is to be obtained. 4. The temperature at which cryoprotectants are added to semen and the time allowed for equilibration are important for subsequent fertility pre- and post-freezing. 5. The type of container used for packaging the semen, freeze or cooling rates, thaw rates and level of cryoprotectant all interact in affecting cell survival. 6. Plastic freeze straws as a packaging device for semen offers the following advantages: easy to handle, require minimal storage space, offer a wide range of freeze and thaw rates, and insemination can be made directly from them upon thawing. 7. Controlled slow cooling rates of 1 to 8$^{\circ}C$/min have thus far provided the best results for cooling chicken semen throught the transition phase change (liquid to solid) or critical temperature range of ＋5 to -20 or -35$^{\circ}C$. 8. Highest fertilities have been achieved with frozen chicken semen where a slow thaw rate (2。 to 5$^{\circ}C$) has been used regardless of the freeze rate. 9. To maintain a constant high level of fertility throughout a breeding season with frozen semen, a higher absolute number of spermatozoa must be inseminated (2 to 3 times as many) as compared to fresh semen since a, pp.oximately 50% are destroyed during processing and freezing. 10. The quality of semen may vary with season and age of the male. Such changes in sperm quality could be accentuated by storage effects. Thus, the correct number of spermatozoa may very well vary during the course of a breeding period. 11. As to time of insemination, it is best to avoid inseminating chicken hens within 1-2 hr after or 3-5 hr before oviposition; and turkey hens during or 7-10 hr before oviposition. 12. The physiological receptiveness of the oviduct at the time of insemination is a very important biological factor influencing fertility levels throughout the breeding season.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.2
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• pp.240-245
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• 2010

The effects of controlled energy restriction and duration of pre-incubation egg holding on fertility, hatchability and hatch losses were evaluated in aged broiler breeders (64 wk). The energy (ME) required for maintenance, activity, growth and anticipated egg production was calculated and offered to a control group (283-471 kcal/kg) from 21-64 weeks of age. In three other groups, ME was quantitatively reduced either by 20% (SER; severe energy restriction) or 10% (MER; moderate energy restriction) and increased by10% (EEF; excess energy feeding) over the control group (CER; controlled energy restriction). Each diet was offered to 130 pullets in individual cages, and the quantity of ME increased with age. At the end of 64 weeks, fertile eggs were collected from each dietary group for 11 consecutive days and grouped under 4 holding periods based on the length of storage (2, 5, 8 or 11 d). The influence of energy regimes, egg holding intervals and their interaction was evaluated on fertility, hatch losses and hatchability. Broiler breeders maintained on SER regime (231-419 kcal/d) produced maximum number of eggs (993) followed by MER (819), CER (624) and EEF (438) during the 11-day period. The percent fertility and hatchability was significantly (p$\leq$0.05) higher in SER and MER groups compared to CER and EEF. However, energy regimes did not influence the loss in egg weight during pre-incubation storage, shell weight, shell thickness or hatch losses as dead germs and dead in shell. The improvement in hatchability in SER and MER groups appeared to be closely related to higher fertility and lower embryonic mortality. Holding of eggs for 11 days showed a linear loss in egg weight with the length of storage, but did not influence the fertility and hatch losses. The percent hatchability on eggs set was maximum when storage period was restricted to 5 days. The interaction between energy regimes and egg holding periods exhibited better hatchability results with SER regime when eggs were held for 5 days. Response to MER was not different from SER. It was obvious that energy restriction during production period had a positive influence on egg number, fertility and hatchability in aged breeders. At 64 weeks of age, holding of fertile eggs for 5 days prior to incubation was adequate for optimum hatchability in breeders.

• Toxicological Research
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• v.24 no.2
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• pp.137-150
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• 2008

Sexually mature male and female rats were orally intubated with the organophosphorus insecticide, Pestban at a daily dosage of 7.45 or 3.72 mg/kg bwt, equivalent to 1/20 and 1/40 $LD_{50}$, respectively. Male rats were exposed for 70 days, while the female rats were exposed for 14 days, premating, during mating and throughout the whole length of gestation and lactation periods till weaning. The results showed depressed acetylcholinesterase(AChE) activity in the brain of parents, fetuses and their placentae in a dose-dependent manner. The fertility was significantly reduced with increasing the dose in both treated groups, with more pronounced suppressive effects in the male treated group. The number of implantation sites and viable fetuses were significantly reduced in pregnant females of both treated groups. However, the number of resorptions, dead fetuses, and pre-and postimplantation losses were significantly increased. The incidence of resorptions was more pronounced in treated female compared to male group and was dose dependant. The behavioral responses as well as fetal survival and viability indices were altered in both treated groups during the lactation period. The incidence of these effects was more pronounced in the treated female group and occurred in a dose-related manner. The recorded morphological, visceral, and skeletal anomalies were significantly increased with increasing the dose in fetuses of both treated groups, with more pronounced effects on fetuses of treated females. In conclusion, the exposure of adult male and female rats to Pestban would cause adverse effects on fertility and reproduction.

• Korean journal of applied entomology
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• v.36 no.3
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• pp.277-282
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• 1997

Chemosterilant effect of chlorpyrifos-methyl (CPM) on the beet armyworm, Spodoptera e.rigua (Hubner) was investigated, using topical application. Egg fecundity and fertility were analyzed in the adults reared from the fifth instar larvae which were treated with sublethal doses of CPM. Though CPM reduced fecundity a little, it gave significant negative effect on egg fertility in a dose-dependent manner. Genetic analysis was performed by reciprocal crosses between treated (100 Wgllarva) and untreated individuals and showed a dominant lethal effect of CPM on egg fecundity and fertility. This results indicate that chlorpyrifos-methyl may act as a chemosterilant as well as a well-known neurotoxicant, and suggest that it can be used in genetic control program.

• Molecules and Cells
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• v.25 no.2
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• pp.294-300
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• 2008

Cytokinins are essential hormones in plant development. $\underline{A}$rabidopsis $\underline{h}$istidine-containing $\underline{p}$hosphotransfer proteins (AHPs) are mediators in a multistep phosphorelay pathway for cytokinin signaling. The exact role of AHP4 has not been elucidated. In this study, we demonstrated young flower-specific expression of AHP4, and compared AHP4-overexpressing (Ox) trangenic Arabidopsis lines and an ahp4 knock-out line. AHP4-Ox plants had reduced fertility due to a lack of secondary cell wall thickening in the anther endothecium and inhibition of IRREGURAR XYLEMs (IRXs) expression in young flowers. Conversely, ahp4 anthers had more lignified anther walls than the wild type, and increased IRXs expression. Our study indicates that AHP4 negatively regulates thickening of the secondary cell wall of the anther endothecium, and provides new insight into the role of cytokinins in formation of secondary cell walls via the action of AHP4.

• Clinical and Experimental Reproductive Medicine
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• v.47 no.2
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• pp.108-113
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• 2020

Objective: Endometrial fibrosis, the primary pathological feature of intrauterine adhesion, may lead to disruption of endometrial tissue structure, menstrual abnormalities, infertility, and recurrent pregnancy loss. At present, no ideal therapeutic strategy exists for this fibrotic disease. Eupatilin, a major pharmacologically active flavone from Artemisia, has been previously reported to act as a potent inducer of dedifferentiation of fibrotic tissue in the liver and lung. However, the effects of eupatilin on endometrial fibrosis have not yet been investigated. In this study, we present the first report on the impact of eupatilin treatment on transforming growth factor beta (TGF-β)-induced endometrial fibrosis. Methods: The efficacy of eupatilin on TGF-β-induced endometrial fibrosis was assessed by examining changes in morphology and the expression levels of fibrosis markers using immunofluorescence staining and quantitative real-time reverse-transcription polymerase chain reaction. Results: Eupatilin treatment significantly reduced the fibrotic activity of TGF-β-induced endometrial fibrosis in Ishikawa cells, which displayed more circular shapes and formed more colonies. Additionally, the effects of eupatilin on fibrotic markers including alpha-smooth muscle actin, hypoxia-inducible factor 1 alpha, collagen type I alpha 1 chain, and matrix metalloproteinase-2, were evaluated in TGF-β-induced endometrial fibrosis. The expression of these markers was highly upregulated by TGF-β pretreatment and recovered to the levels of control cells in response to eupatilin treatment. Conclusion: Our findings suggest that suppression of TGF-β-induced signaling by eupatilin might be an effective therapeutic strategy for the treatment of endometrial fibrosis.

• Journal of the Korean Statistical Society
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• v.5 no.2
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• pp.143-158
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• 1976

The purpose of this article is, first, to argue that the fertility cannot be reduced rapidly through widerspread diffusion of contraceptive practices which has been the main drive of the national policy in population control, because there involves the inescapable externalites in procreation, second, family sizes tend to be larger because of the financial externalities arising from government subsidies to families with children, and finally, the decreasing relative risk aversion of households with wealth may induce the poor to have large family sizes.