• Development and Reproduction
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• v.1 no.2
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• pp.157-164
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• 1997

To study the regulation of porcine follicular cell apostosis by gonadotropin, steroid, and nitric oxide, we analyzed DNA fragmentation, the hallmark of apoptosis, and nitrite production of porcine granulosa cells. Dissected indiidual follicles from ovary were separated in size (small, 2-3 mm; medium, 5-6 mm; large, 7-8 mm) and isolated granulosa cells were classified morpholocally as atretic or nonatretic. Nitrite concentration was measured by mixing follicular fluids with an equal volume of Griess reagent. Follicular nitric oxide (NO) concentration of healthy follicles was higher than that of atretic follicles. Apoptotic DNA fragmentation was suppressed in non-apoptotic granulosa cells. Follicular apoptosis was induced by androgen but prevented by gonadotropin in vitro. Apoptosis was confined to the granulosa cells. But it was not clear whether apoptosis of granulosa cells were isolated, incubated with or without gonadotropin, androgen and sodium nitroprusside (SNP), respectively at $37^{\circ}C$ for 24 hrs. Cultured granulosa cells were used to extract genomic DNA and culture media was asssayed for nitrite concentration. Nitrite production of culture media was increased, while apoptotic DNA fragmentation was suppressed in PMSG, hCG, testosterone+SNP and SNP treated groups. Nitrite concentration in culture media was decreased, but apoptotic DNA fragmentation was induced in testosterone treated group. These data suggest that NO production and apoptosis may be involved of granulosa cell apoptosis induced by testosterone.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.1045-1050
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• 2002

The aims of this study were to detect spontaneously occurring apoptosis in cultured porcine ovarian cells, to examine the role of growth hormone (GH), tyrosine kinase (TK), protein kinase G (PKG) and cyclin-dependent kinase (CDK) in the control of this process, and to determine whether the effect of GH on apoptosis is mediated by TK-, PKG- and cdc2-dependent intracellular mechanisms. We studied the action of pGH (10 ng/ml), blockers of TK (genistein, lavendustin, both 100 ng/ml), PKG (Rp-Br-PET-cGMPS, 50 nM; KT5823, 100 ng/ml) and CDK (olomoucine, $1{\mu}g/ml$), as well as combinations of GH with these blockers, on the onset of apoptosis in cultured granulosa cells isolated from antral (3-6 mm) porcine follicles. The functional characteristics of an early apoptotic event, DNA fragmentation, were determined using terminal deoxynucleotidyltransferase (TdT)-mediated dUTP nick end labelling (TUNEL), whilst morphological signs of advanced apoptosis such as pyknosis, chromatin marginalization, shrinkage and fragmentation of nucleus, were detected using routine light microscopy. After culture, some ovarian granulosa cells exhibited DNA fragmentation, which in some cases was associated with morphological apoptosis-related changes (pyknosis, shrinkage and fragmentation of the nucleus). GH significantly reduced the proportion of TUNEL-positive cells. Neither TK nor CDK blockers when given alone, significantly affected the percentage of TUNEL-positive cells although both PKG blockers significantly increased this index. Furthermore, TK and PKG blockers given together with GH, prevented or reversed the inhibitory effect of GH on apoptosis, whilst the CDK blocker olomoucine promoted it. These observations demonstrate apoptosis in porcine ovaries and suggest the involvement of GH, TK, PKG and CDK in the control of this process. They also suggest that the effect of GH on ovarian apoptosis is mediated or regulated by multiple signalling pathways including TK-, PKG- and CDK-dependent intracellular mechanisms.

• The Journal of Korean Medicine
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• v.22 no.4
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• pp.37-44
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• 2001

Objectives : Cellular death by apoptosis is an active process, depending on gene transcription and protein synthesis. It was reported that nitric oxide can induce apoptosis in several cancer cell-lines. We have previously observed that proliferation of Ll210 cells was inhibited by the administration of Gleditsiae Spina water extract (GE). In this present study, the mechanism of inhibitory action on the proliferation of L l210 cells was examined. Methods : The cell proliferation was determined by MTT assay and DNA fragmentation was determined by a flow cytometry. Results : The administration of GE decreased proliferation of L1210 cells and enhanced DNA fragmentation in vivo system. DNA fragmentation of L1210 cells was enhanced by co-culture of peritoneal macrophages obtained from GE-administered mice in vitro and it was partly inhibited by L-NMMA, nitric oxide synthetase inhibitor. In addition, GE increased nitric oxide production from peritoneal macrophages of L1210-transplanted mice. Conclusions : These results suggest that the inhibitory action of GE on proliferation of transplanted-L1210 cells is partly caused by an induction of apoptosis via production of nitric oxide in macrophages.

• East Asian Economic Review
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• v.24 no.4
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• pp.389-416
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• 2020

This paper provides empirical evidence on the reorganization of GVCs in East Asia, highlighting that structural trends explain a decrease in the fragmentation of production after 2011 but that it is not the result of rising trade costs along the value chain. Using harmonized inter-country input-output tables, the paper first analyzes the global import intensity of production to document changes in the structure of GVCs. It then calculates theory-consistent bilateral trade costs for intermediate and final products using an approach derived from the gravity literature and introduces a new index of cumulative trade costs along the value chain. These data are used to discuss whether the decrease in global imports is the consequence of shifts in demand, efficiency-enhancing strategies of firms or rising trade costs. Between 2011 and 2016, cumulative trade costs have decreased in East Asian GVCs. However, as COVID-19 is likely to intensify trade and investment uncertainties, trade costs could increase in the future. Policies aimed at reducing uncertainties and preserving the gains from trade and investment liberalization will be key in this new environment.

• Explosives and Blasting
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• v.36 no.4
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• pp.9-15
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• 2018

Since the rock fragmentation by blasting can affect the subsequent processes including loading, hauling and secondary crushing, its control is essential for the assessment of blasting efficiency as well as production cost. In this study, we were analyzed the rock fragmentation by the direction of artificial joint. The underground blasting experiments were performed after forming the vertical and horizontal artificial joints. The blast fragmentation was conducted by the split-desktop which is a 2D image processing program. As a result, it was found that the horizontal artificial joint was evaluated to have lower overall the size of muck pile than the vertical artificial joint and the distribution of the size of muck pile was varied. It is possible that the direction of artificial joint could suppress the occur of oversize muck pile and control to a certain size or less.

• Explosives and Blasting
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• v.32 no.3
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• pp.1-9
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• 2014

Since the rock fragmentation from a bench blasting can affect the subsequent processes including loading, hauling and crushing, its control is essential for the assessment of blasting efficiency as well as production cost. In this study, the delay time could be precisely controlled by using electronic detonators. The rock fragmentations resulted from the blastings with different delay times of 1, 2, 3, 4, 5, 7 and 10ms per each meter of burden were measured from full scale field tests in a limestone mine. The results showed that the optimum delay time for minimum fragmentation was approximately 6ms/m. From the analysis of fragmentation size distribution, it was possible to find that delay time can be a parameter on rock fragmentation and thus it would be possible to control rock fragmentation by adjusting delay time.

• Environmental Analysis Health and Toxicology
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• v.19 no.3
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• pp.251-259
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• 2004

Xenoestrogens are chemicals with diverse structure that mimic estrogen. Bisphenol A, a monomer of polycarbonate and epoxy resins, has been detected in canned food and human saliva. Bisphenol A stimulate cell proliferation and induce expression of estrogen -response genes in vitro. The purpose of the this study was to evaluate cell proliferation of bisphenol A in the presence of a rat liver 59 mix contaning cytochrome P450 enzymes and Cu (II). The fragmentation of intact DNA, a parameter of apoptotic cell death, was evaluated quantitatively by diphenylamine reaction method. Bisphenol A induced apoptotic cell death in a dose-dependent manner The effect of radical scavenger on the apoptotic cell death induced bisphenol A was investigated. The DNA fragmentation induced by bisphenol A was significantly inhibited by addition of radical scavenger to the culture medium. This indicated that elevated oxidative stress caused by imbalance between the production and removal of free radicals occurred in cells. Taken together, these results suggest that free radical reacts with Cu (II) leading oxidative stress.

• Geomechanics and Engineering
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• v.14 no.2
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• pp.151-159
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• 2018

Annually, the global production of construction aggregates reaches over 40 billion tons, making aggregates the largest mining sector by volume and value. Currently, the aggregate industry is shifting from sand to hard rock as a result of legislation limiting the extraction of natural sands and gravels. A major implication of this change in the aggregate industry is the need for understanding rock fragmentation and energy absorption to produce more cost-effective aggregates. In this paper, we focused on incorporating dynamic rock and soil mechanics to understand the effects of loading rate and water saturation on the rock fragmentation and energy absorption of three different sandstones (Red, Berea and Buff) with different pore sizes. Rock core samples were prepared in accordance to the ASTM standards for compressive strength testing. Saturated and dry samples were subsequently prepared and fragmented via fast and dynamic compressive strength tests. The particle size distributions of the resulting fragments were subsequently analyzed using mechanical gradation tests. Our results indicate that the rock fragment size generally decreased with increasing loading rate and water content. In addition, the fragment sizes in the larger pore size sample (Buff sandstone) were relatively smaller those in the smaller pore size sample (Red sandstone). Notably, energy absorption decreased with increased loading rate, water content and rock pore size. These results support the conclusion that rock fragment size is positively correlated with the energy absorption of rocks. In addition, the rock fragment size increases as the energy absorption increases. Thus, our data provide insightful information for improving cost-effective aggregate production methods.

• Tunnel and Underground Space
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• v.14 no.5
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• pp.353-362
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• 2004

Prediction of fragmentation in bench blasting is one of the most important factors to establish the production plan. It is widely accepted that fragmentation could be accurately predicted using the Kuz-Ram model in bench blasting. Nevertheless, the model has an ambiguous or subjective aspect in evaluating the model parameters such as joint condition, rock strength, density, burden, explosive strength and spacing. This study proposes a new method to evaluate the parameters of Kuz-Ram model, and the predicted mean fragment sizes using the proposed method are examined by comparing the measured sizes in the field. The results show that the predictions using Kuz-Ram model with the proposed method coincide with field measurements, but Kuz-Ram model does not reflect the in-situ rock condition and hence needs to be improved.

• 지반과기술
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• v.3 no.3
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• pp.15-22
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• 2006

The optimum blasting pattern to excavate a quarry efficiently and economically can be determined based on the minimum production cost, which is generally estimated according to rock fragmentation. Therefore, it is a critical problem to predict fragment size distribution of blasted rocks over an entire quarry. By comparing various prediction models, it can be ascertained that the result obtained from Kuz-Ram model relatively coincides with that of field measurements. Kuz-Ram model uses the concept of rock factor to signify conditions of rock mass such as block size, rock jointing, strength and others. For the evaluation of total production cost, it is imperative to estimate 3-D spatial distribution of rock factor for the entire quarry. In this study, a sequential indicator simulation technique is adopted for estimation of spatial distribution of rock factor due to its higher reproducibility of spatial variability and distribution models than Kriging methods. Further, this can reduce the uncertainty of predictor using distribution information of sample data. The entire quarry is classified into three types of rock mass and optimum blasting pattern is proposed for each type based on 3-D spatial distribution of rock factor. In addition, plane maps of rock factor distribution for each ground level are provided to estimate production costs for each process and to make a plan for an optimum blasting pattern.