• Particle and aerosol research
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• v.6 no.2
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• pp.81-90
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• 2010

Several studies have suggested the possibility of airborne transmission of infectious diseases such as tuberculosis, pandemic influenza. because the number of patients increases explosively, if infectious disease had a high basic reproduction number, pharmaceutical interventions such as vaccination, chemoprophylaxis in the early stage of epidemic. Thus, non-pharmaceutical interventions such as mask-wearing, installing air cleaners, school closure are important to control and prevent the infectious diseases. However, the current technology on the mask, air cleaning, ventilation, and etc., seems to be not originated from the understanding of infection via airborne transmission. It is important to estimate the aerodynamic behavior of saliva droplets by coughing or speaking in order to understand the phenomena of airborne infection. In addition, the prediction of transmission of infectious diseases through the air is critical to prevent or minimize the damage of infection. In this review, we reviewed the recent studies on the airborne infection by focusing on the aerodynamic characteristics of saliva droplets and modeling of airborne transmission.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.18 no.4
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• pp.317-335
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• 2014

In this work, we investigate the global stability analysis of a viral infection model with antibody immune response. The incidence rate is given by a general function of the populations of the uninfected target cells, infected cells and free viruses. The model has been incorporated with two types of intracellular distributed time delays to describe the time required for viral contacting an uninfected cell and releasing new infectious viruses. We have established a set of conditions on the general incidence rate function and determined two threshold parameters $R_0$ (the basic infection reproduction number) and $R_1$ (the antibody immune response activation number) which are sufficient to determine the global dynamics of the model. The global asymptotic stability of the equilibria of the model has been proven by using Lyapunov theory and applying LaSalle's invariance principle.

• Animal Bioscience
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• v.34 no.6
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• pp.975-984
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• 2021

Objective: Inbreeding depression of reproduction is a major concern in the conservation of native chicken genetic resources. Here, based on the successful development of strongly inbred (Sinb) and weakly inbred (Winb) Langshan chickens, we aimed to evaluate inbreeding effects on reproductive traits and identify candidate genes involved in inbreeding depression of reproduction in Langshan chickens. Methods: A two-sample t-test was performed to estimate the differences in phenotypic values of reproductive traits between Sinb and Winb chicken groups. Three healthy chickens with reproductive trait values around the group mean values were selected from each of the groups. Differences in ovarian and hypothalamus transcriptomes between the two groups of chickens were analyzed by RNA sequencing (RNA-Seq). Results: The Sinb chicken group showed an obvious inbreeding depression in reproduction, especially for traits of age at the first egg and egg number at 300 days (p<0.01). Furthermore, 68 and 618 differentially expressed genes (DEGs) were obtained in the hypothalamus and ovary between the two chicken groups, respectively. In the hypothalamus, DEGs were mainly enriched in the pathways related to vitamin metabolism, signal transduction and development of the reproductive system, such as the riboflavin metabolism, Wnt signaling pathway, extracellular matrix-receptor interaction and focal adhesion pathways, including stimulated by retinoic acid 6, serpin family F member 1, secreted frizzled related protein 2, Wnt family member 6, and frizzled class receptor 4 genes. In the ovary, DEGs were significantly enriched in pathways associated with basic metabolism, including amino acid metabolism, oxidative phosphorylation, and glycosaminoglycan degradation. A series of key DEGs involved in folate biosynthesis (gamma-glutamyl hydrolase, guanosine triphosphate cyclohydrolase 1), oocyte meiosis and ovarian function (cytoplasmic polyadenylation element binding protein 1, structural maintenance of chromosomes 1B, and speedy/RINGO cell cycle regulator family member A), spermatogenesis and male fertility (prostaglandin D2 synthase 21 kDa), Mov10 RISC complex RNA helicase like 1, and deuterosome assembly protein 1) were identified, and these may play important roles in inbreeding depression in reproduction. Conclusion: The results improve our understanding of the regulatory mechanisms underlying inbreeding depression in chicken reproduction and provide a theoretical basis for the conservation of species resources.

• Development and Reproduction
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• v.19 no.3
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• pp.145-152
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• 2015

Diphlorethohydroxycarmalol (DPHC) is a known to modulate the expression of extracellular matrix (ECM) components in 3T3-L1. However, the possible role of DPHC in integument stability during obesity induction is not clear yet. We evaluated the effects of DPHC on collagen or elastic fiber quantity in integument during obesity induction with high-fat diet. The dorsal back integument sections were stained with hematoxylin-eosin, Masson trichrome, and Verhoff-Van Gieson. The intensities of collagen fibers and elastin fibers were analyzed with ImageJ. The number of fibroblasts was counted at ${\times}1,000$ fields. The number of fibroblast was increased by obesity induction, but DPHC suppressed it in a concentration-dependent manner both in lean and obese mice. On the other hand, the intensities of collagen fibers were increased by DPHC treatment in obese mice groups but not in lean mice groups. The intensities of collagen fibers of obese mice were lower than that of the lean mice in 0% group. However, the number became similar between lean and obese mice by the treatment of DPHC. The intensity of elastic fibers was increased in the lean mice with the concentration of DPHC. In the obese mice group, there were increasing patterns but only significant at 10% DPHC group. The intensity of elastic fibers of obese mice was higher than lean mice in 0%, 1%, and 10% groups. Histologically epithelial cells and follicle cells which were diffused nuclear staining forms were increased by DPHC treatment. The results suggest that the activity of integument cells during obesity induction can be modulated by DPHC.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.2
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• pp.76-81
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• 2021

Halla horse is crossbreed between Jeju and Thoroughbred horses and is used for riding, racing and meat production. Thus, molecular genetic studies are needed to establish and preserve the industrially valuable Halla horses. This study aimed to analyses the genetic diversity and population structure through 12 microsatellite (MS) markers for Halla and putatively related 3 breeds (Jeju, Mongolian and Thoroughbred horses). On average, the number of alleles, observed heterozygosity (H_obs), expected heterozygosity (H_exp), and polymorphic information content (PIC) among all horses were 10, 0.767, 0.799, and 0.771, respectively. Neighbor-joining tree and STRUCTURE analysis showed that Halla horses were between Thoroughbred and Jeju horses, tend to more influenced by Thoroughbred horses. Therefore, these results could be considered for use as the basic genetic breed relationships resource among the horse breeds (Jeju, Mongolian, and Thoroughbred horses) related to the origins of the Halla horse.

• Korean Journal of Animal Reproduction
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• v.24 no.1
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• pp.77-82
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• 2000

This study was conducted to establish the methods of ultrasound-guided transvaginal retrieval of oocytes (ovum pick-up) in Korean native, Hanwoo Heifers. To obtain the basic data about Hanwoo, the size of ovaries in luteal and follicular phases were measured and the number of follicles in ovaries during the estrus cycle was counted by using ultrasound. And to determine the effective anesthetic to Hanwoo, various mixture of anesthetic compounds, Rompun(equation omitted), lidocaine, Monzal(equation omitted), and Domosedan(equation omitted), were treated. The size of Hanwoo ovaries were not significant differently between luteal and follicular phases. The number of medium and small follicles were peak on day 3 and 12 of the estrous cycle, and this result suggested that Hanwoo has 2 follicular growth waves per estrus cycle. The most effective anesthetic method was intramuscular injection of a.3m! Rompun(equation omitted), epidural injection of 5$m\ell$ lidocaine and sprayed cervix by 2$m\ell$ lidocaine.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.3
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• pp.154-161
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• 2021

A number of Korean Chicken breeds were registered in Domestic Animal Diversity Information System (DAD-IS, http://dad.fao.org/) of the Food and Agriculture Organization (FAO). Evaluation of genetic diversity and relationship of local breeds is an important factor towards the identification of unique and valuable genetic resources. Therefore, this study aimed to analysis the genetic diversity and relationship of 22 Korean Chicken breeds using 12 microsatellite (MS) markers. The mean number of alleles for each variety was 5.52, ranging from a 3.75 (Leghorn F; NF) to a 7.0 (Ross). The most diverse breed was the Hanhyup3 (HCC), which had the highest expected heterozygosity (H_Exp) (0.754) and polymorphic information content (PIC) (0.711). The NF was the least diverse population, having the lowest H_Exp (0.467) and PIC (0.413). As a result of the principal coordinates analysis (PCoA) and factorial correspondence analysis (FCA) confirmed that Hy-line Brown (HL) and Lohmann Brown (LO) are very close to each other and that Leghorn and Rhode Island Red (RIR) are clearly distinguished from other groups. Thus, the reliability and power of identification using 12 types of MS markers were improved, and the genetic diversity and probability of individual discrimination were confirmed through statistical analysis. This study is expected to be used as basic data for the identification of Korean chicken breeds, and our results indicated that these multiplex PCR marker sets will have considerable applications in population genetic structure analysis.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.3
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• pp.232-238
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• 2020

This study used adult wistar-based rats to observe the sexual cycle as a morphological characteristic of vaginal epithelial cells by vaginal smearing, and investigated the fetal number through mating with male rats of the same strain. The target animal was a 12 to 13-week-old Wistar-based mature unlighted rat (weight 220 g to 240 g), room temperature 23 ± 2℃, 14 hours artificial lighting (05:00 to 19:00 hours), 10 hours Adapted individuals were used for rearing for at least 2 weeks under the conditions of the darkroom (19:00 to 05:00). The feed was managed for free feeding of pellet feed for animals and water. The vaginal smearing method was used for the experiments by observing the sexual cycle every morning and confirming that the normal sexual cycle of 4 or 5 days was repeated at least 2 cycles or more. As a result, the proestrus was found to have few red blood cells, the cells and nuclei were rather large and round, and many nucleated cells were identified. In the case of the estrus, the cells were large and the nuclei were not stained, and most of the keratinocytes were found. In addition, in the metestrus and diestrus, there were many white blood cells, and it was confirmed that nucleated epithelial cells and keratinocytes were significantly reduced. The pregnancy period was 21 ± 1.8 days, and the number of live births per delivery was 11.9 on average. The number of fetuses on the 8th and 10th days of pregnancy were 15.2 ± 0.4 and 15.4 ± 0.3, respectively. On the contrary, the number of fetuses on the 12th day of pregnancy was 12.9 ± 0.6, which was significantly (p < 0.05) decreased compared to the 10th day of pregnancy, and the number of fetuses was similar until delivery. As a result of investigating the change of body weight according to the birth weight and growth stage after delivery, the birth weight of female and male was 9.2 ± 2.0 g and 9.8 ± 2.5 g, respectively. After that, until the 16th day, the female and the male showed similarly moderate weight gain, and then showed a rapid weight gain until the 21st day of lactation. With reference to the results of this study, it is expected to be used as basic data for determining the mating time of rodents and controlling pregnancy and fetal number.

• Bulletin of the Korean Mathematical Society
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• v.48 no.3
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• pp.555-574
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• 2011

It is well known that the mathematical models provide very important information for the research of human immunodeciency virus type. However, the infection rate of almost all mathematical models is linear. The linearity shows the simple interaction between the T-cells and the viral particles. In this paper, a differential equation model of HIV infection of $CD4^+$ T-cells with Crowley-Martin function response is studied. We prove that if the basic reproduction number $R_0$ < 1, the HIV infection is cleared from the T-cell population and the disease dies out; if $R_0$ > 1, the HIV infection persists in the host. We find that the chronic disease steady state is globally asymptotically stable if $R_0$ > 1. Numerical simulations are presented to illustrate the results.

• Bulletin of the Korean Mathematical Society
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• v.54 no.6
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• pp.1893-1912
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• 2017

In this paper, we aim to construct a nonstandard finite difference (NSFD) scheme to solve numerically a mathematical model for cholera epidemic dynamics. We first show that if the basic reproduction number is less than unity, the disease-free equilibrium (DFE) is locally asymptotically stable. Moreover, we mainly establish the global stability analysis of the DFE and endemic equilibrium by using suitable Lyapunov functionals regardless of the time step size. Finally, numerical simulations with different time step sizes and initial conditions are carried out and comparisons are made with other well-known methods to illustrate the main theoretical results.