• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.318-325
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• 2021

The objective of this study was to identify the effect of zebularine, a DNA methylation inhibitor, on the chromosomal association between homoeologous chromosomes in the wheat genetic background. Zebularine at a final concentration of 10 µM was used to treat the spikes of the double monosomic wheat addition line (DMA) with one Leymus mollis chromosome and one Leymus racemosus chromosome, both of which were in a homoeologous relationship. In late prophase, zebularine led to chromosome breakage in the Leymus homoeologous chromosomes. Chromosome breakage caused an increase in the frequency of chromosomal associations between the Leymus homoeologous chromosomes. Ordinary DMA showed 65 cells (35.3%) with chromosomal associations and 119 cells (64.7%) with no association, whereas treated DMA showed 102 cells (60.0%) with chromosomal associations and 67 cells (39.4%) with no association. In diakinesis, the Leymus bivalent showed a chromosomal association in the whole euchromatic region. In metaphase, the Leymus bivalent showed association in the whole chromosomal region, unlike other Leymus bivalents with partial chromosomal association. Chromosomal association by chromosome breakage occurred not only between Leymus chromosomes but also between Leymus and wheat chromosomes. The frequency of other chromosomal association (such as fusion and insert) was increased. Chromosome breakage by zebularine treatment is a useful method at the chromosome level as the spores with others are hereditary stable, although the homologous index (h) was not significantly different between ordinary DMA and treated DMA. It is necessary to study how to control zebularine treatment with a more stable concentration for chromosome breakage during meiosis.

• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.23-30
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• 2023

This study was conducted to analyze the correlation between egg breakage rate and cumulative external forces on eggs during the egg transfer system in 12 commercial layers farms. The commercially available electronic egg device was used to detect the external forces on eggs during egg collection systems. In addition, egg breakage rate per farm was collected. It was found that the external force on eggs were greater in the order of washer and dryer connection part, conveyor connection part, transfer, sorter, collecting elevator, packer, egg transfer connection part, and egg tray. A positive relationship between the external forces on eggs during egg transit system and the incidence of cracked eggs per farm was noted. The external forces on eggs varied from 5G to 38G depending on the location and the egg breakage rate ranged from 3.2 to 14.5% per farm. Although efforts to produce eggs with high eggshell quality are considered important, extra care should be made to lower the external forces on eggs during the egg transfer system from laying house to egg packing center.

• Bulletin of the Korean Chemical Society
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• v.29 no.12
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• pp.2395-2398
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• 2008

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1891-1893
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• 2006

• Fibers and Polymers
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• v.4 no.2
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• pp.71-76
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• 2003

We evaluated the seam characteristics with finishing, seaming and sealing processes and seam Puckering behavior of the breathable waterproof fabrics with laser scan. There were differences in 99% significant level between the seamed fabric and the sealed fabric. Seam breakage was initiated with the breakage of sewing thread, so the seam strength after seaming was almost uniform. The sewn seam strength and elongation increased with sealing process in all finishing methods. Pucker grade of laminating type was generally much higher than that of the coating type. We confirmed that wave length and amplitude have more important meaning than the number of weave in the breathable waterproof fabrics. The puckering in breathable waterproof fabrics is mainly occurred by inherent and feeding pucker. The former if due to the insertion of sewing thread and the littler is caused by differential feeding when two pieces of fabric are fed into the gap between a press foot and needle plate.

• Environmental Mutagens and Carcinogens
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• v.17 no.2
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• pp.71-77
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• 1997

The single cell gel electrophoressis(SCGE) assay, also known as the comet assay, is a rapid, simple, visual and sensitive technique for measuring and analysing DNA breakage in mammalian cells. The SCGE or comet assay is a promising test for the detection of DNA damage and repair in individnal cells. It has widespread potential applications in DNA damage and repair studies, genotoxicity testing and biomonitoring. In this microgel electrophoresis technique, cells are embedded in agarose gel on microscope slides, iysed and electrophoresed under alkaline conditions. Cells with increased DNA damage display increased migration of DNA from the nucleus towards the anode. The length of DNA migration indicates the amount of DNA breakage in the cell. The comet assay is also capable of identifying apoptotic cells which contain highly fragmented DNA. Here we review the development of the SCGE assay, existing protocols for the detection and analysis of comets, the relevant underlying principles determining the behaviour of DNA and the potential applications of the technique.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.245-250
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• 2002

A successful on-line monitoring system for conventional machining operations has the potential to reduce cost, guarantee consistency of product quality, improve productivity and provide a safer environment for the operator. In fee-shape machining, typical signs of tool problems such as vibration, noise, chip flow characteristics and visual signs are almost unnoticeable without the use of special equipment. These characteristics increase the importance of automatic monitoring in fine-shape machining; however, sensing and interpretation of signals are more complex. In addition, the shafts of the micro-tools break before the typical extensive cutting edge of the tool gets damaged. In this study, the existence of a relationship between the characteristics of the cutting force and tool usage was investigated, and tool breakage detection algorithm was developed and the fellowing results are obtained. In data analysis, didn't use a relative error compare which mainly used in established experiment and investigated tool breakage detection algorithm in time domain which can detect AE and cutting force signals more effective and accurate.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.5
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• pp.144-149
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• 2000

The demands for robotic and automatic system are continually increasing in manufacturing fields. There have been many studies to monitor and predict the system, but they have mainly focused upon measuring cutting force, and current of motor spindle, and upon using acoustic sensor, etc. In this study, time series sequence of cutting force was acquired by taking advantage of piezoelectric type tool dynamometer. Radial cutting force was obtained from it and was available for useful observation data. The parameter was estimated using PAA(parameter adaptation algorithm) from observation data. ARMA(auto regressive moving average) model was selected for system model and second order was decided according to parameter estimation. Uncorrelation test was also carried out to verify convergence of parameter.

• Applied Microscopy
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• v.14 no.2
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• pp.38-51
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• 1984

Fine structure of dormant and swollen conidiospore from Trichoderma koningii and the mechanism of protoplasting from the conidiospore were studied by scanning and transmission electron microscopy. The cell wall of dormant conidiospore was two-layered structure which consisted of electron dense outer layer and electron transparent inner layer. After 8.5 hrs incubation. the conidiospore was swollen and the outer layer of cell wall shown unequal thickness and partial breakage. Protoplast was released through the pore which has been formed by the breakage of outer layer and dissolution of newly synthesized cell wall for germ-tube formation. Swollen conidiospore and protoplast in releasing process contained various cell organelles and vacuoles with electron dense materials. The protoplast contained looser cytoplasm and had no cell wall materials outside of plasmamembrane.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.1
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• pp.133-139
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• 2004

High speed machining (HSM) can reduce machining time with the high metal removal rate by high speed spindle and feedrate. This paper supports HSM technology using the small size tool with the optimal tool path generation and modification of tool change. The optimum tool path is generated to reduce cutting length of cavity pattern and change the cutting tool for preventing the tool breakage by wear. The tool path is modified with the experiment data of tool wear and breakage to support tool change on reasonable time. The result can contribute to HSM technology of high hardness materials using the small size end-mill.