• 한국축산식품학회지
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• 제41권6호
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• pp.923-935
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• 2021

Fresh grass carp was used to produce surimi samples that were supplemented with 50 g/kg, 100 g/kg, or 150 g/kg pork back fat. The lipid composition, lipase activity, lipid oxidation index, and lipoxygenase activity of samples subjected to repeated freezethaw process were determined to assess the effects of the added fat on lipolysis and lipid oxidation of grass carp surimi. Freeze-thaw treatment increased free fatty acid content, mainly due to the decomposition of phospholipids and some neutral lipids by lipase. With repeated freeze-thaw treatment, the levels of free fatty acids and phospholipids were correlated with the lipid oxidation indexes and lipoxygenase activity, indicating that lipid degradation can promote lipid oxidation. In the same freeze-thaw cycle, surimi products with high fat content are more vulnerable to oxidative damage, neutral lipids are the main source of free fatty acids in the early stage of freeze-thaw, and phospholipids are the main source of free fatty acids in the late stage.

• 한국동물생명공학회지
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• 제37권1호
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• pp.48-54
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• 2022

Parthenogenesis is maternally uniparental reproduction through the embryonic development of oocytes without fertilization. Artificial activation of mature oocytes could generate homozygous haploid embryos with the extrusion of the second polar body. However, the haploid embryos showed low embryo development in preimplantation embryos. In this study, we investigated whether the electronic fusion of the haploid embryos could enhance embryo development and ESC establishment in mice. Haploid embryos showed the developmental delay from 4-cell to the blastocyst stage. The haploid blastomeres of the 2-cell stage were fused electronically, resulting in that the fused embryos showed a significantly higher rate of blastocysts compared to non-fused haploid embryos (55% vs. 37%). Further, the embryonic stem cells (ESCs) derived from the fused embryos were confirmed to be diploid. The rate of ESC establishment in fused embryos was significantly higher compared to non-fused ones. Based on the results, we concluded that the electronic fusion of haploid embryos could be efficient to generate homozygous ESCs.

• 한국공간구조학회논문집
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• 제23권3호
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• pp.105-113
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• 2023

The study used the whole-life carbon assessment method to conduct a thorough carbon-neutral evaluation of a standard steel structure. To further assess carbon emissions, 11 design-changed models were evaluated, with changes made to the span between beams and columns. The results of the carbon emission assessment showed savings of approximately 13.1% by implementing the stage of the beyond life cycle. Additionally, the evaluation of carbon emissions through design changes revealed a difference of up to 42.2%. These findings confirmed that recycling and structural design changes can significantly reduce carbon emissions by up to 48.6%, making it an effective means of achieving carbon neutrality. It is therefore necessary to apply the stage of beyond life cycle and structural change to reduce carbon emissions.

• Animal cells and systems
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• 제5권1호
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• pp.51-57
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• 2001

We have previously shown that oocyte maturation is induced by an immobilized progesterone, progesterone-3-carboxymethyloxime - bovine serum albumin conjugate (P-BSA) in Rana dybowskii. In this study, we confirmed the maturation inducing activity of P-BSA on Xenopus oocyte and examined the binding character of the immobilized progesterone on the surface of Xenopus oocytes after removal of the vitelline layer. P-BSA induced maturation of Xenopus oocytes but E-BSA failed to do so as observed in Rana. Binding of the immobilized progesterone, fluorescein isothiocyanate-labeled progesterone-3-0-carboxymethyloxime-BSA (P-BSA-FITC) on the devitellined oocytes surface was examined by fluorescence confocal microscopy. The binding affinity of P-BSA-FITC to the devitellined oocyte was higher than that of estrogen-BSA-FITC (E-BSA-FITC) or testosterone-BSA-FITC (T-BSA-FITC). The binding disappeared in the presence of excess free progesterone but not in the presence of free estrogen. Maximum binding occurred after two-hours of incubation with P-BSA-FITC at pH 7.5. Stronger binding occurred in oocytes at stage Vl than stage IV, and in vitro treatment of hCG enhanced the binding. Taken together, these results suggest that a specific receptor for progesterone exists on the plasma membrane of Xenopus oocytes and that progesterone acts initially on this putative receptors and triggers generation of membrane-mediated second messengers during the early stage of oocyte maturation In amphibians.

• 대한간호학회지
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• 제45권4호
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• pp.604-612
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• 2015

Purpose: The purpose of this study was to investigate the levels of physical symptoms, anxiety, depression, and quality of life (QOL) during chemotherapy for colorectal cancer patients in South Korea and to identify factors influencing their QOL. Methods: Data were collected from 144 colorectal cancer patients receiving chemotherapy during 2012 at one general hospital located in Seoul. Physical symptoms were measured by the M. D. Anderson Symptom Inventory-Gastrointestinal Cancer Module, and anxiety and depression were measured by the Hospital Anxiety Depression Scale. QOL was measured by the Functional Assessment of Cancer Therapy-Colorectal. Data were analyzed using descriptive statistics, t-test, one-way ANOVA, $Scheff{\acute{e}}$ post hoc test, Pearson correlation and stepwise multiple regression. Results: Mean age of the participants was 56.6 and most of them were not employed. In terms of cancer stage, 38.2% were in stage 3, followed by stage 4 (34.7%). The most frequent symptom was lack of appetite, followed by sleep disturbance and fatigue. The mean score for anxiety was 5.40 with a prevalence of 23% and that of depression 8.85 with a prevalence of 64.6%. The mean score for quality of life was 81.93 out of 136 and 75.3% of the variance in QOL was explained by depression, symptoms, anxiety, treatment place, and occupational status. Depression was the strongest predictive factor. Conclusion: Oncology professionals need to pay special attention to relieving depression as well as physical symptoms to improve QOL during chemotherapy for colorectal cancer patients.

• 대한기계학회논문집B
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• 제37권12호
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• pp.1153-1157
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• 2013

증기터빈의 터빈 블레이드는 발전소 핵심설비 중 하나로, 로터의 디스크에 결합되어 회전함으로 써 증기 에너지를 기계적 에너지로 변환시켜주는 역할을 하고 있다. 최근 터빈의 잦은 기동정지로 인해 블레이드 회전에 따른 원심하중이 반복적 작용하고 이에 따른 저압 증기터빈 최종단 블레이드의 손상이 자주 보고되고 있다. 본 논문에서는 터빈 블레이드에 발생되는 손상을 분석하여 블레이드에 발생되는 저주기 피로수명을 평가하였다. 증기터빈 최종단 블레이드의 균열발생 수명을 결정하기 위해 유한요소법으로 계산한 탄성응력에 Neuber's rule을 적용하여 진변형율 진폭을 계산하였으며, 예측된 수명과 블레이드 실제 기동정지횟수가 잘 일치됨을 보였다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권11호
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• pp.1665-1672
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• 2008

Interspecies somatic cell nuclear transfer (iSCNT) is a useful method to preserve endangered species and to study the reprogramming event of a nuclear donor cell by the oocyte. Although several studies of iSCNT using murine cells and bovine oocytes have been reported, the development of murine-bovine iSCNT embryos beyond the 8-cell stage has not been successful. In this paper, we examined the developmental potential of embryos reconstructed with a murine embryonic fibroblast as the nuclear donor and a bovine oocyte as the cytoplasm recipient. The reconstructed embryos were cultured in CZB (murine medium) or CR1aa (bovine medium). In addition, for the development of a murine-bovine iSCNT blastocyst, the antioxidant ${\beta}$-mercaptoethanol (${\beta}ME$) was supplemented to CR1aa medium. Furthermore, to verify the mouse genome activation in murine-bovine iSCNT embryos, RT-PCR analysis of murine Xist was performed. The development of the murine-bovine iSCNT embryos cultured in CR1aa was significantly higher than that in CZB (p<0.05). With respect to the effect of BME on the development of the murine-bovine iSCNT blastocyst, addition of BME produced a significant increase in blastocyst development (p<0.05). Karyotype analysis confirmed that the reconstructed embryos were derived from murine cells (40XX). The Xist gene was gradually increased from the 8-cell stage to the blastocyst stage. This is the first report of blastocyst development of iSCNT embryos derived from murine somatic cells and bovine oocytes. These results demonstrate that bovine cytoplasm can support the development of later stages of a preimplantation embryo from murine-bovine iSCNT.

• Animal cells and systems
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• 제4권3호
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• pp.223-229
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• 2000

Limbs and supporting structures of an organism experience a full weight of its own when it lands from water, because neutral buoyancy in the aquatic habitat will be no longer available in the terrestrial world. Metamorphosis of anuran amphibians presents 8 good research model to examine how this transition from non-loading to weight-loading affects development of motor capacity at the time of their first emergence on land. Our video analysis of the transitional anurans, Rana catesbeiana, at Gosner stage 46 (the stage of complete transformation) demonstrated that the take-off speed increased 1.23-fold after the first six hours of weight-loading on the wet ground. It did not increase further during the following three days of loading, and was close to the level of mature frogs with different body mass. During development of larvae in deep water with no chance of landing through metamorphosis, both tension and power of a hindlimb anti-gravity muscle increased 5-fold between stages 37 and n. However, the muscle contractility increased more rapidly when the larvas could access the wet ground by their natural landing behavior after stages 41-42. Muscle power, one of major factors affecting locomotory speed, was 1.29-fold greater in the loaded than in the non-loaded larvae at the transitional stage. Thus, weight-loading had a potentially significant effect on the elevation of motor capacity, with a similar extent of increment in locomotory speed and muscle power during the last stages of metamorphosis. Such a motor adjustment of the froglets in a relatively short transitional period would be important for effective ecological interactions and survival in their inexperienced terrestrial life.

• Plant Breeding and Biotechnology
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• 제1권1호
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• pp.1-8
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• 2013

Low-temperature stress is an important factor controlling the growth and development of rice (Oryza sativa L.) in temperate region. In this study, a molecular linkage map consisting of 136 SSR markers was employed to identify QTL associated with cold tolerance at the seedling stage. 80 recombinant inbred lines (RILs) from an intersubspecific cross between Milyang23 (O. sativa ssp. Indica) and Hapcheonaengmi3, a japonica weedy rice and the parents were evaluated for leaf discoloration and SAPD value of seedlings. Rice plants were grown for 15 days in the low-temperature condition (13/20℃ day/night) and the control condition (25/20℃ day/night) in the growth chamber. The degree of leaf discoloration showed a highly significant correlation with the SPAD value in the low-temperature plot (r = -0.708, P < 0.0001). A total of four QTLs for SPAD were identified and the phenotypic variance explained by each QTL ranged from 5.4 to 16.0%. Two QTLs detected in the control condition were located on chromosomes 2 and 5, respectively. Two QTL on chromosomes 1 and 4 were detected at the low-temperature condition and Hapcheonaengmi3 alleles increased the SPAD values at these loci. Substitution mapping was conducted to delimit the position of qSPA-4 using introgression lines derived from the same cross. Results indicated that qSPA-4 was located in a 810-Kb region flanked by RM16333 and RM16368. The results indicated that Hapcheonaengmi3 contains QTL alleles that are likely to improve cold tolerance of Indica rice.

• 대한기계학회논문집A
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• 제31권11호
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• pp.1083-1092
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• 2007

The objective of the present paper is to evaluate the effect of the evolution of contact surface profile caused by fretting wear on fatigue life of press-fitted shaft by means of an analytical method based on experimental data. A finite element analysis was performed to analyze the stress states of press-fitted shaft, considering the worn contact profiles of shaft. The fatigue lives of the press-fitted shaft reflecting the evolution of contact stress induced by fretting wear were evaluated by stress-life approach using fatigue notch factor. It is found that the stress concentration of contact edge in press-fitted shaft decreases rapidly at the initial stage of total fatigue life, and its location shifts from the contact edge to the inside with increasing number of fatigue cycles. Thus the change of crack nucleation position in press-fitted shaft is mainly caused by the stress change of contact edge due to the evolution of contact surface profile by fretting wear. Furthermore, the estimated fatigue lives by stress-life approach at the end of running-in period of the fretting wear process corresponded well to the experimental results. It is thus suggested that the effect of fretting wear on fatigue life in press fits is strongly related to the evolution of surface profile at the initial stage of total fatigue life.