• Clinical and Experimental Reproductive Medicine
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• v.38 no.2
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• pp.82-86
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• 2011

Objective: To evaluate sperm nuclear DNA fragmentation and chromatin structure after 18 hours' incubation at room temperature. Methods: Twenty-eight male partners who participating IVF treatment were prospectively included in this study. Ejaculated sperm count and motility were assessed. The sperm was then immediately processed by the conventional swim-up method. After utilization of some of the sample for routine clinical use, the remainder of each of the samples was divided into two aliquots. One aliquot was immediately assessed for sperm nuclear DNA fragmentation (TUNEL assay) and chromatin structure (toluidine blue [TB] staining). The other aliquot was incubated at room temperature for 18 hours and then assessed by two methods. Only dark-TB sperms were considered as having abnormal chromatin structure. Data before and after extended incubation were compared using a paired Student's $t$-test. Results: Before and after extended culture, nuclear DNA fragmentation assessed by TUNEL was $4.9{\pm}4.7%$ and $7.0{\pm}6.4%$, respectively ($p$=0.008). The proportion of abnormal chromatin structure (dark-TB sperm) was $8.2{\pm}5.6%$ and $10.3{\pm}6.5%$ ($p$ <0.001), before and after incubation, respectively. Conclusion: After 18 hours' incubation at room temperature, sperm nuclear DNA and chromatin structure were significantly affected. The IVF practitioner should bear this information in mind when performing delayed insemination, especially for $in$ $vitro$ maturation cycles.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.283-291
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• 2024

Sodium cooled Fast Reactors (SFR) are built with several engineered safety features and hence a severe accident such as a core melt accident is hypothetical with a probability of <10^-6/ry. However, in case of such accidents, the mixture of the molten fuel and structural materials interacts with sodium. This phenomenon is known as Molten Fuel Coolant Interaction (MFCI) and results in fragmentation of the melt due to various instabilities. The fragmented particles settle as a debris bed on the core catcher at the bottom of the reactor vessel, and continue to generate decay heat. Characteristics of the debris particles play a vital role in heat transfer from the bed and need thorough investigation. The size, shape, and physical state of the debris depend on the associated fragmentation mechanism, superheating of the melt, and sodium temperature. Experiments have been conducted by releasing simulated corium, a molten mixture of alumina and iron generated by the aluminothermy process at ~2400 ℃ into liquid sodium, to study the fragmentation phenomena. After the experiment, the fragmented debris was retrieved and the particle size distribution was determined by sieve analysis. The debris was subjected to microscopic investigation for obtaining morphological characteristics. Based on the characteristics of debris, an attempt has been made to assess of fragmentation mechanism of simulated corium in sodium.

• Animal cells and systems
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• v.16 no.2
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• pp.104-113
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• 2012

The nucleolus is a distinct nuclear territory involved in the compartmentalization of nuclear functions. There is some evidence of a relationship between nuclear fragmentation during spermatogenesis and chromatoid body (CB) formation. The CB is a typical cytoplasmic organelle of haploid germ cells, and is involved in RNA and protein accumulation for later germ-cell differentiation. The goal of this study was to qualitatively and quantitatively describe the nucleolar cycle during the spermatogenesis of $Phrynops$ $geoffroanus$ (Reptilia Testudines), and compare this nucleolar fragmentation with CB formation in this species through the use of cytochemical and ultrastructural analysis. Qualitative analysis showed a fragmentation of the nuclear material after pachytene of the first meiotic division in the primary spermatocytes. Quantitative analysis of the nucleolar cycle revealed a significant difference in the number of nucleoli and in the size of the nucleolus between spermatogonia and early spermatids. Using ultrastructural analysis, we recorded the beginning of the CB formation process in the cytoplasm of primary spermatocytes at the same time as when nuclear fragmentation occurs. In the cytoplasm of primary spermatocytes, the CB was observed in association with mitochondrial aggregates and the Golgi complex. In the cytoplasm of early spermatids, the CB was observed in association with lipid droplets. In conclusion, our data show that the nucleolus plays a role in the CB formation process. During spermatogenesis of $P.$ $geoffroanus$, the CB is involved in some important biological processes, including acrosome formation and mitochondrial migration to the spermatozoon tail and middle piece region.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.1
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• pp.35-43
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• 2009

Objectives: Seminal concentration of tumor necrosis factor-alpha (TNF-${\alpha}$) relevant to sperm nuclear DNA integrity has not been studied. The present study aimed to evaluate seminal concentration of TNF-${\alpha}$ in correlation with sperm parameters and nuclear DNA integrity in asymptomatic healthy donors. Methods: Semen samples were obtained by masturbation from forty-five healthy donors. Results: Sperm quality was assessed by computer-assisted semen analysis and nuclear DNA integrity measured by the TUNEL assay in raw semen. TNF-${\alpha}$ concentrations were measured by ELISA in frozen-thawed seminal plasmas. Sperm DNA fragmentation rates were ranged between 1.9% and 53.0% (mean${\pm}$SD, 12.4${\pm}$9.6%). Univariate analysis revealed that DNA fragmentation rate was not associated with sperm concentration or motility but had a correlation with linearity negatively (r=-0.325, p=0.03) and age positively (r=0.484, p=0.001). The mean seminal concentration of TNF-${\alpha}$ was 4.9 pg/mL with a range from 1.1 to 22.6 pg/mL. The TNF-${\alpha}$ concentration had no correlation with clinically relevant parameters of sperm quality or nuclear DNA fragmentation rate. Conclusion: Our results indicate that sperm nuclear DNA fragmentation may be not associated with seminal TNF-${\alpha}$ level or sperm quality in asymptomatic healthy donors.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2402-2409
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• 2020

Analytical criteria for the onset of fuel fragmentation and Burst Fission Gas Release in fuel rods with ballooned claddings are formulated. On that basis, the GRSW-A model integrated with a fuel behaviour code is updated. After modification, the updated code is successfully applied to simulation of the Halden LOCA test IFA-650.12. Specifically, the calculation with Burst Fission Gas Release during the test resulted in prediction of cladding failure, whereas it could not be predicted at the test planning, before new models were implemented. A good agreement of the current model with experimental data for transient Fission Gas Release in the tests IFA-650.12 and IFA-650.14 is shown, as well.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.136-136
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• 2003

Mainly due to deficiencies in nuclear reprogramming, gene expression and DNA fragmentation, which result in early and late embryonic losses, the overall success rate achieved by cloning techniques to date is low. This present study compared the incidences of DNA fragmentation during development of IVF, parthenotes (PT), nuclear transfer (NT) and transgenic (TG) embryos. Terminal deoxynucleotidyl transferase (TdT) nick-end labelling (TUNEL) with propidium iodide counter staining was used for determination of DNA fragmentation and total number, respectively. TG and NT donor cells were fetal fibroblasts with or without transfection with EGFP, and cultured in DMEM+15% FCS until confluent, for 5 days. At 19 h post-maturation (hpm), enucleated oocytes were reconstructed with donor cells and activated at 24 hpm with the combinations of ionomycin (5 M, 5 min) and cyclo-heximide (10 g/ml, 5 h) after electric fusion by a single DC pulse (1.6 KV/cm, 60 sec). Parthenotes were produced by the same activation protocol at 24 hpm. (중략)

• Toxicological Research
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• v.20 no.1
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• pp.63-69
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• 2004

Casapse-3 protease is known as a key role of apoptotic enzyme, and caspase-3 activity is a central event that occurs upstream of DNA fragmentation during apoptosis. This study demonstrates that chitosan pretreatment inhibits cadmium-induced apoptosis by attenuating the activity of caspase-3. We also analyzed the protective effect of chitosan on DNA fragmentation induced by cadmium. Cadmium toxicity was examined by DNA fragmentation and nuclear condensation with Hoechst stain. Caspase-3 activities were increased cadmium treated group for 3 hours compared with control. When chitosan (150 mg/ml) was pretreated at 30 min before cadmium treatment, cadmium cytotoxicity was suppressed in a dose-dependent manner evaluated by DNA fragmentation and caspase activity. From these results, it is suggest that the protective effect of chitosan pretreatment against cadmium-induced cytotoxicity is mediated through inhibition of caspase-3 protease activation and DNA fragmentation.

• Nuclear Engineering and Technology
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• v.36 no.3
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• pp.276-284
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• 2004

This paper presents the results of the TEXAS-V computer code simulations of FARO L-14, L-28, and L-33. The old break-up model and new break-up model are tested to compare the respective simulations of each. As these experimental data sets cover a wide range of ambient pressures, sub-cooling of the water pool, and the melt jet diameters, the results of the simulations will be beneficial in assessing the TEXAS-V code's capability to predict the steam explosion phenomena in a prototypical reactor case. The current model was found to have some deficiencies, and the modules for the fragmentation, the equation of state, and the interfacial area for each flow regime in TEXAS-V were improved for the simulation of FARO L28 and FARO L-33.

• Development and Reproduction
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• v.26 no.3
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• pp.99-105
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• 2022

Styrene is the precursor of polystyrene. Human exposure to styrene could occur in occupational and residential settings and via food intake. Styrene is metabolized to styrene-7,8-oxide by cytochrome P450 enzyme. In the present study, we investigated the cytotoxicity mediated by styrene and styrene-7,8-oxide in TM3 testicular Leydig cells in vitro. We first monitored the nuclear fragmentation in Leydig cells after exposure to styrene or styrene-7,8-oxide. Hoechst 33258 cell staining showed that styrene exposure in TM3 Leydig cells did not exhibit nuclear fragmentation at any concentration. In contrast, nuclear fragmentation was seen in styrene-7,8-oxide-exposed cells. These results indicate that cytotoxicity-mediated cell death in Leydig cells is more susceptible to styrene-7,8-oxide than to styrene. Following styrene treatment, procaspase-3 and XIAP protein levels did not show significant changes, and cleaved (active) forms of caspase-3 were not detected. Consistent with the western blot results, the active forms of caspase-3 and XIAP proteins were not prominently altered in the cytoplasm of cells treated with styrene. In contrast to styrene, styrene-7,8-oxide induced cell death in an apoptotic fashion, as seen in caspase-3 activation and increased the expression of XIAP proteins. Taken together, the results obtained in this study demonstrate a fundamental idea that Leydig cells are capable of protecting themselves from cytotoxicity-mediated apoptosis as a result of styrene exposure in vitro. It remains unclear whether the steroid-producing function, i.e., steroidogenesis, of Leydig cells is also unaffected by exposure to styrene. Therefore, further studies are needed to elucidate the endocrine disrupting potential of styrene in Leydig cells.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.72.1-72
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• 2003

Generally, plants defend themselves against pathogens by structural and biochemical reactions. Defense structures act as physical barriers and inhibit the pathogen from gaining entrance and spreading through the plant. Xanthomonas axonopodis pv glycines, the causal pathogen of bacterial pustule of soybean, causes hypersensitive response (HR). When pepper fruits were inoculated with X. axonopodis pv. glycines, in situ, time-series defense-related structural changes occurred in the inoculated sites. Early responses were programmed cell death (PCD), characterized by condensation and vacuolization of the cytoplasm, condensation of nuclear materials, and fragmentation of the nuclear DNA, which were observed by transmission electron microscopy. Nuclear fragmentation was proven by TUNEL method under confocal laser scanning microscopy and DNA laddering through eletrophoresis. At later stages, plant responses were cell elongation and cell division, forming a periderm-like boundary layer that demarcated healthy tissues from the inoculation sites. Using several stains such as toluidine blue, sudan IV, annexin V, and phloroglucinol-HCl, defense-related materials and structural changes were also examined.