• Korean Journal of Poultry Science
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• v.7 no.1
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• pp.1-11
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• 1980

About 6 to 8% of the eggs annually produced are broken or cracked between the hen and the consumer's carton. The majority of this breakage is due to interrelationships between egg shell quality and the many biological, environmental and managerial factors which have been individually identified as affecting breakage. Some of the factors associated with shell damage discussed in this review include age of hens, temperature ana humidity of the laying house, design of the cage systems and of the cage floors, type of material used to manufacture the cages frequency of daily egg collection in the laying house and, Probably most important, the frequency and quality of handling equipment maintenance. Age and genetic constitution of the hens, environmental temperature, and design and quality of equipment maintenance are the major factors that influence shell breakage. There is a curvilinear relationship between shell quality and shell breakage which explains why small changes in shell quality may be associated with large changes in the incidence of breakage. Published data indicate the incidence of breakage may range from as low as 1 to 2% to 35% or more for other egg producers.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.195-195
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• 2019

최근 센싱 기술과 정보화의 영향으로 하천에서 발생하는 다양한 정보들이 디지털화되어 저장되고 있으며, 이를 효율적으로 저장하고 관리하고자 하는 연구가 수행되고 있다. 특히, 과거에는 점, 선, 면으로 구성된 자료 위주로 구성되어 있어 수집된 자료를 주제별로 관리하는 레이어 형식으로 저장하여 자료를 표출하기 위한 목적으로 설계되었지만, 최근에는 영상자료, 시계열자료 등 기존의 자료와 다른 비구조적 형태의 자료가 발생함에 따라 하천 네트워크를 기반으로 한 하천공간정보를 관계형 구조로 설계하고 있다. 하천의 경우, 각 하천공간정보가 가지는 고유의 값을 활용하여 인접한 하천 네트워크를 구성하는 하천의 중심선 혹은 최심선을 기준으로 하천공간정보들을 관계성을 부여한다. 하지만 이러한 관계성은 자료의 저장, 관리, 제공에는 유리한 측면이 있지만 기하학적인 고려가 없기 때문에 공간정보로서 활용하기에는 한계가 존재한다. 쉽게 설명하면, 1차원 점에 해당하는 공간좌표는 가장 가까운 하천 네트워크를 대상으로 관계성 부여가 가능하지만, 2차원 선과 3차원 면에 해당하는 도형을 대표하는 위치가 공간적으로 많기 때문이다. 본 연구에서는 하천 네트워크 기반 공간정보가 관계성을 부여하되 하천공간정보가 가지는 기하하적 구조를 반영하기 위해 하천 네트워크를 중심으로 한 곡선좌표계 부여 방법을 제시하고자 한다. 하천은 실제로 연속적으로 변화하며, 곡선으로 이루어져 있기 때문에 공간적으로 직교좌표계를 활용하기 보다는 곡선좌표계를 활용하는 것이 더 적합한 것으로 알려져 있다. 실제로 많은 수치해석 모형에서는 곡선좌표계를 고려하여 수치해석을 수행하고 있으며, 도로나 교통 분야의 공간정보에서도 공간적 고려를 위해 곡선좌표계를 활용하는 것으로 알려져 있다. 본 연구에서는 하천 중심선 혹은 최심선을 기준으로 흐름방향 거리를 S, 횡방향 거리를 N으로 설정하여 곡선좌표계를 정의하였으며, 직교좌표계와 곡선좌표계간의 좌표변환을 위해 이차원 변환방법인 투영변환을 활용하였다. 본 연구에서 제시된 방법을 활용할 경우, 하천 네트워크 기반 공간정보가 자료 간의 관계성을 유지하며, 기하하적 고려가 될 것으로 사료된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.266-266
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• 2019

금강의 주요 지류인 미호천과 갑천은 대전광역시와 청주시가 위치하고 있으며, 두 도시지역에서 유입되는 오염물질로 인하여 금강 본류에 높은 오염부하를 제공하고 있다. 따라서 본 연구에서는 3차원 수리동역학 모델인 EFDC 모델을 사용하여 미호천과 갑천의 수질개선이 금강의 수질에 미치는 효과를 분석하였다. 대상유역은 대청댐부터 백제보 까지 70km 구간이며, 모델의 격자는 Curvilinear-Orthogonal Coordinate를 사용하였으며 횡단방향 8개로 분할하여 총 6,698개의 격자로 구성하였다. 경계조건구성 및 모델의 보정은 국가정보 포털인 수자원관리종합정보시스템(WAMIS), 물환경정보시스템(WEIS), 국가기후데이터센터(data,kma,go,kr) 등에서 제공하는 유량, 수질, 기상 등 데이터를 활용하였으며, 모의 기간은 2017년이다. 수질의 보정은 대상유역 내 6곳의 수질 측정 지점에서 수행되었으며, 적합성 평가를 위해 R-square와 NSE(Nash-Sutcliffe Efficiency) 두 가지의 통계 지표를 활용하였다. 수질의 경우 TN, TP, TOC, Chl-a 순으로 평균 R-square값은 0.75, 0.51, 0.36, 0.57이고 평균 NSE (Nash-Sutcliffe Efficiency)값은 0.59, -0.18, -1.10, 0.27으로 모의 값과 실측값 사이의 상관관계는 TN에서 가장 높았으며 반대로 TOC는 가장 낮았다. 모의결과가 실측값을 정확히 반영하지는 못했지만, 수질의 평균적인 현상은 반영한 것으로 판단된다. 두 주요 지류의 수질이 동시에 15% 또는 30% 개선되었을 경우를 모의하여 금강 본류의 수질변화를 6곳의 수질 측정 지점에서의 실측값과 비교하여 분석하였다. 두 지류가 동시에 15%의 수질 개선 시에는 금강 본류 수질은 TN, TP, TOC, Chl-a 순으로 평균 11.80%, 7.90%, 8.63%, 7.04%의 개선되었으며, 30% 수질 개선 시에는 평균 23.66%, 15.92%, 17.36%, 14.26%의 개선되었다. 각 지점에서 고른 개선이 확인되었으며, 개선 효과는 TN이 가장 컸고, 반대로 Chl-a가 가장 적었다. 갑천과 미호천의 수질이 별개로 개선되었을 경우를 모의한 결과, 미호천의 개선이 갑천에 비해 금강의 수질 개선에 영향이 컸다. 이는 두 지류의 수질 농도는 비슷하나 갑천에 비해 유량이 많은 미호천의 오염 부하량이 높은 것으로 분석된다. 연구 결과 금강의 수질을 개선하기 위해서는 두 지류의 수질 개선이 필수적인 것으로 판단된다. 금강의 TN 농도는 두 지류의 영향이 가장 컸으며, 개선 효과는 Chl-a에서 가장 적었다. 또한 갑천에 비해 미호천이 금강 수질에 영향이 큼을 확인하였다.

• Geomechanics and Engineering
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• v.11 no.1
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• pp.141-160
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• 2016

This study elucidates the uplift behaviors of the straight-sided and belled shafts. The field uplift load tests were carried out on 18 straight-sided and 15 belled shafts at the three collapsible loess sites under an arid environment on the Loess Plateau in Northwest China. Both the site conditions and the load tests were documented comprehensively. In general, the uplift load-displacement curves of the straight-sided and belled shafts approximately exhibited an initial linear, a curvilinear transition, and a final linear region, but did not provide a well defined peak or asymptotic value of the load, and therefore their uplift resistances should be interpreted from the load test results using an appropriate criterion. Nine representative uplift resistance interpretation criteria were used to define the "interpreted failure load" for each of the load tests, and all of these interpreted uplift resistances were normalized by the failure threshold, $T_{L2}$, obtained using the $L_1-L_2$ method. These load test data were compared statistically and graphically. For the straight-sided and belled shafts, the normalized uplift load-displacement curves were respectively established by the plots that related the mean interpreted uplift resistance ratio against the mean displacement at the corresponding interpreted criteria, and the comparisons of the normalized load-displacement curves were made. Specific recommendations for the designs of uplift belled and straight-sided shafts in the loess were given, in terms of both capacity and displacement.

• Animal Bioscience
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• v.34 no.12
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• pp.1912-1920
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• 2021

Objective: This study investigated the effects of 5-aminolevulinic acid (5-ALA) on the motility parameters, mitochondrial membrane depolarization, and ATP levels in chicken sperm. Methods: The pooled semen from Barred Plymouth Rock males was used. In the first experiment, the semen was diluted 4-times with phosphate-buffered saline (PBS (-)) containing various concentrations (0, 0.01, 0.05, and 0.1 mM) of 5-ALA, and then the sperm motility parameters after incubation were evaluated by computer-assisted sperm analysis (CASA). In the second experiment, the semen was diluted 4-times with PBS (-) containing 0.05 mM 5-ALA, and then sperm mitochondrial membrane depolarization and ATP levels after 1.5 h of incubation were analyzed with the MitoPT^® JC-1 Assay and ATP Assay kits, respectively. In the third experiment, the semen was removed from the seminal plasma and resuspended with the mediums of PBS (-), PBS (-) supplemented with CaCl₂ and MgCl₂ (PBS (+)) + 5-ALA, PBS (+) + caffeine, and PBS (+) + caffeine + 5-ALA. Then, the sperm motility parameters after incubation were evaluated by CASA. In the last experiment, the semen was treated with the mediums of PBS (-), PBS (-) + 5-ALA, 5.7% glucose, 5.7% glucose + 5-ALA after removing the seminal plasma, and then the sperm motility parameters were evaluated by CASA. Results: The addition of 0.05 mM 5-ALA significantly increased the chicken sperm motility, progressive motility, linearity, average path velocity, curvilinear velocity, straight-line velocity, and the wobble. The sperm mitochondrial membrane depolarization was also increased by the 5-ALA treatment. The 5-ALA treatment decreased the sperm ATP levels. Both the caffeine treatment and glucose treatment decreased the sperm motility during incubation period. Conclusion: 5-ALA might increase sperm mitochondrial membrane depolarization to utilize the ATP for enhancing sperm movement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.470-476
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• 2019

The braking force for a train is generally provided by compressed air. The pressure valve system that is used to apply appropriate braking forces to trains has a complex flow circuit. It is possible to make a channel shape that can increase the flow efficiency by 3D printing. There are restrictions on the flow shape design when using general machining. Therefore, in this study, the compressed air flow was analyzed in a pressure valve system by comparing flow paths made with conventional manufacturing methods and 3D printing. An analysis was done to examine the curvature magnitude of the flow path, the diameter of the flow path, the magnitude of the inlet and reservoir pressure, and the initial temperature of the compressed air when the flow direction changes. The minimization of pressure loss and the uniformity of the flow characteristics influenced the braking efficiency. The curvilinear flow path made through 3D printing was advantageous for improving the braking efficiency compared to the rectangular shape manufactured by general machining.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.195-204
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• 2019

In this study, we examined the effect of a liposome-based extender (Optixcell) and a tris-citric egg-yolk extender (Triladyl) on the frozen-thawed spermatozoa characteristics and the calving rate. The percentages for the total motility of the frozen-thawed spermatozoa were similar in the Optixcell and Triladyl groups. However, among the motile spermatozoa with a straight line velocity (VSL) ${\geq}25{\mu}m/sec$, the curvilinear velocity (VCL, ${\mu}m/sec$), VSL (${\mu}m/sec$), average path velocity (VAP, ${\mu}m/sec$), amplitude of lateral head displacement (ALH, ${\mu}m$), beat cross frequency (BCF, Hz), and plasma membrane integrity of the frozen-thawed spermatozoa for the Optixcell group were significantly higher than those for the Triladyl group. Furthermore, the calving rate in the Optixcell group (79.0%) was higher than that of the Triladyl group (62.8%). However, the acrosomal membrane integrity of the frozen-thawed spermatozoa in the Optixcell and Triladyl groups was not significantly different. These results indicate that semen freezing with Optixcell improved the motility and plasma membrane integrity of frozen-thawed spermatozoa and the calving rate of Hanwoo cows (native Korean cattle). In conclusion, our results suggest that semen freezing with the liposome-based extender Optixcell is more efficient than with the tris-citric egg-yolk extender Triladyl for improved offspring production.

• Animal Bioscience
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• v.35 no.2
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• pp.166-176
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• 2022

Objective: Sperm is particularly susceptible to reactive oxygen species (ROS) stress. Glutathione (GSH) is an endogenous antioxidant that regulates sperm redox homeostasis. However, it is not clear whether boar sperm could utilize cysteine for synthesis GSH to protect sperm quality from ROS damage. Therefore, the present study was undertaken to elucidate the mechanism of how cysteine is involved in protecting boar sperm quality during liquid storage. Methods: Sperm motility, membrane integrity, lipid peroxidation, 4-hydroxyIlonenal (4-HNE) modifications, mitochondrial membrane potential, as well as the levels of ROS, GSH, and, ATP were evaluated. Moreover, the enzymes (GCLC: glutamate cysteine ligase; GSS: glutathione synthetase) that are involved in glutathione synthesis from cysteine precursor were detected by western blotting. Results: Compared to the control, addition of 1.25 mM cysteine to the liquid storage significantly increased boar sperm progressive motility, straight-line velocity, curvilinear velocity, beat-cross frequency, membrane integrity, mitochondrial membrane potential, ATP level, acrosome integrity, activities of superoxide dismutase and catalase, and GSH level, while reducing the ROS level, lipid peroxidation and 4-HNE modifications. It was also observed that the GCLC and GSS were expressed in boar sperm. Interestingly, when we used menadione to induce sperm with ROS stress, the menadione associated damages were observed to be reduced by the cysteine supplementation. Moreover, compared to the cysteine treatment, the γ-glutamylcysteine synthetase (γ-GCS) activity, GSH level, mitochondrial membrane potential, ATP level, membrane integrity and progressive motility in boar sperm were decreased by supplementing with an inhibitor of GSH synthesis, buthionine sulfoximine. Conclusion: These data suggest that boar sperm could biosynthesize the GSH from cysteine in vitro. Therefore, during storage, addition of cysteine improves boar sperm quality via enhancing the GSH synthesis to resist ROS stress.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.285-291
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• 2022

In 1951, Colin Russell Austin and Min Chueh Chang identified "capacitation", a special process involving ejaculated spermatozoa in the female reproductive tract. Capacitation is a phenomenon that occurs in vivo, but almost all knowledge of capacitation has been obtained from in vitro studies. Therefore, numerous trials have been performed to establish in vitro capacitation methods for various studies on reproduction. Although a series of studies have been conducted to develop an optimal protocol for inducing capacitation, most have focused on identifying the appropriate chemical compounds to induce the capacitation of boar spermatozoa in vitro. Therefore, the purpose of this study was to identify the optimal incubation time for inducing capacitation in vitro. Duroc semen was incubated for various periods (60, 90, and 120 min) to induce capacitation. Sperm function (sperm motility, motion kinematic parameters, and capacitation status) was evaluated. The results showed that total sperm motility, rapid sperm motility, progressive sperm motility, curvilinear velocity, and average path velocity significantly decreased in a time-dependent manner. However, the capacitation status did not show any significant changes. Taken together, these results indicate that an incubation time of more than 60 min suppresses sperm motility and motion kinematic parameters. Therefore, we suggest that 60 min may be the best incubation time to induce capacitation without negative effects on sperm motility and motion kinematics in boar spermatozoa in vitro.

• Fisheries and Aquatic Sciences
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• v.26 no.5
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• pp.318-335
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• 2023

It is important to understand the biological aspects of fish for fishing management. This study was conducted from February through October 2021. A total of 1,629 fishes were collected using different fishing gears. The length-weight relationship is a power curve for all fishes and showed a significant (r² > 0.8). All fishes revealed a negative allometric growth pattern except Labeobarbus intermedius. Oreochromis niloticus (1.714 ± 0.009) was found in better condition than other fish species (analysis of variance [ANOVA], p < 0.05). The length at maturity was 24.0 cm and 25.4 cm total length (TL), 28.9 cm and 28.2 cm fork length, and 53.2 cm and 57.5 cm TL for females and males of O. niloticus, L. intermedius and Clarias gariepinus, respectively. Fecundity was ranged between 100-947 eggs/g with absolute fecundity (AF) of 468-3,832 eggs, 200-1,000 eggs/g with AF of 2,752-136,420 eggs, and 505-900 eggs/g with AF of 2,000-6,404 eggs for O. niloticus, C. gariepinus, and L. intermedius, respectively. Their respective mean fecundity was 1,490 ± 91, 23,330 ± 5,070, and 3,096 ± 273 eggs, respectively. Mean fecundity revealed a significant variation between size classes and species (ANOVA, p < 0.05). The fecundity length and fecundity-body weight relationships except (O. niloticus) of fishes were curvilinear while the gonad weight (GW)-fecundity relationship was linear for all fish species. The fecundity was moderately associated with increasing length than body weight, and GW for all fishes (r² > 0.6). In conclusion, a tangible management setup is required to sustain the use of fish in the reservoir.