• Journal of Sensor Science and Technology
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• v.32 no.6
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• pp.412-417
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• 2023

There is increasing interest in the rapid and highly sensitive monitoring of cell viability in biological and toxicological research. Conventional methods depend on optical assays using Water Soluble Tetrazolium-8 (WST-8) or 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, which requires a large volume of samples and special instruments, necessitating shipment of clinical samples to laboratories. This paper reports on the development of a rapid and sensitive electrochemical (EC) sensor using screen printed electrode (SPE) and surface modification using 4'-mercapto-N-phenylquinone diamine (4'-NPQD), as double electron mediators, for monitoring cell viability via the measurement of nicotinamide adenine dinucleotide (NADH). We used the sensor to observe the viability of MCF-7 and doxorubicin (Dox)-treated cells. The oxidation current of NADH was measured via chronoamperometry (CA), and the EC results showed a good linear relationship when compared with NADH quantification using WST-8 assay. The analysis time was only 10 s and limit of detection (LOD) of NADH was 1.78 µM. Our EC method has the potential to replace conventional WST assays for cell viability and cytotoxicity experiments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.432-438
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• 2013

This study was conducted to compare seed viability among 42 species after ten years of storage in the midterm storage complex ($4^{\circ}C$, 30-40% RH) at the National Agrobiodiversity Center (NAC) Korean genebank maintained by the Rural Development Administration (RDA), Republic of Korea and to suggest the relative seed longevity and suitable monitoring intervals. The germination data from initial tests and after ten years of storage were compared to measure changes in viability during storage. The decline in seed viability varied greatly among seeds from -11.5% for Triticum sp. to 80% for melon. Coriander, crowndaisy, safflower, cosmos, Chinesebellflower, waxgourd, melon, castorbean, Welch-onion, hollyhock, wild barley, and tallfescue showed significant decreases in viability of 34.2%, 73.4%, 36.5%, 30.0%, 40.2%, 71.3%, 80.0%, 65.9%, 45.5%, 51.4%, 53.0%, and 33.5%, respectively. Gardenpea, soybean, perilla, onion, wild rice, Italian-ryegrass, and pepper showed a 15-30% decline in viability, while the viability of morningglory, adzukibean, maize, and Capsicum sp. decreased by 15% to 5%. Chicory, radish, Chinese-cabbage, bottlegourd, watermelon, cucumber, pumpkin, Cucurbita sp., groundnut, kidneybean, clubwheat, sesame, wheat, Triticum sp., rice, barley, orchardgrass, buckwheat, and wild tomato showed changes in viability of <5%. The changes in storage viability also varied within families. The wild types of rice and barley showed rapid viability loss and presented different aspects from cultivars. Since seed viability of species, classified as index 1 or 2, showed germination losses >15% after ten years of storage, a viability test should be conducted with five year intervals, while species with germination loss of <15% (in index 3 or 4) can be retested at ten year intervals.

• Environmental Engineering Research
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• v.23 no.3
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• pp.282-287
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• 2018

Three different methods of bacterial viability monitoring were compared to detect chemically or thermally inactivated Escherichia coli. Direct colony enumeration, live/dead bacterial cell staining with a fluorescent dye, and the dehydrogenase activity assay were compared with respect to their ease of use and time required to perform the three different tests. The green (live cell)/red (dead cell) ratio obtained from the fluorescent bacterial cell staining approach showed a linear relationship with the colony forming units; the result obtained with dehydrogenase was similar to those. The sensitivity of the monitoring methods to detect bacterial deactivation varied with different disinfection conditions. After thermal treatment, the sensitivity of the staining approach was lower, while that of the dehydrogenase activity assay was the highest. After chemical treatment, the sensitivity of detection for both methods was similar.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1098-1105
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• 2001

There is little information on smallholder dairy farming in Zimbabwe. With such inadequate knowledge, no meaningful decisions on how to improve these systems can be made. A study was, therefore, carried out in Nharira communal area and Lancashire small-scale commercial area to provide information on the viability of dairy farms. This paper is based on data obtained through participatory monitoring of 13 smallholder dairy farms in 1996 and 1997. All the four farms in Lancashire were found to be viable in both years. In Nharira, two out of the nine farms in 1996 and three farms in 1997 failed to break even. There were considerable inter-farm differences in the contribution of milk sales towards total income from dairy farming, ranging from 41% to 99% in Nharira and 71% to 81% in Lancashire in 1996. Corresponding estimates in 1997 were 51-95% and 72-78%, respectively. Expenses on cattle feeds contributed 36-84% in 1996 and 37-80% in 1997 towards total variable costs in Nharira. In Lancashire, the respective estimates were 15-33% and 22-36%. Seven out of the nine studied farms in Nharira and three out of four in Lancashire realized higher gross margin (GM) in 1997 than in 1996. All these farming households had conserved considerable amounts of farm-grown feeds. It was concluded that feed costs, number of cows and sizes of land holdings were the main factors determining viability of smallholder dairy farming. The major challenge to smallholder dairy farming in Nharira, in particular, was to develop low-cost feeding strategies.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.901-905
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• 2012

We present an electroporation and viability monitoring chip for lung cancer cells in a single channel with multiple electric field zones. Previous electroporation chips utilized multiple microchannels or electrodes to form multiple electric fields, thus resulting in complex structures. However, the present chip can generate multiple electric fields in a single stepwise microchannel between a pair of electrodes, thus achieving the analysis of both cell electroporation and viability with a simple structure. We demonstrate that the electric field of 0.4 kV/cm results in a maximum percentage of $51.4{\pm}3.0%$ and $26.6{\pm}0.7%$ of viable and electroporated human lung cancer cells, H23 and A549, respectively. The present chip has potential for use in integrated cell chips for transfection studies.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.3
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• pp.202-206
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• 2000

The genetically-engineered Escherichia coli strain, DPD2540, which contains a fabA:::luxCDAbefusion gene, gives a bioluminescent output when membrane fatty acid synthesis is needed. For more pactical application of this strain in the filed as biosensor, freezedrying was adopted. A 12% surcrose solution with Luria-Bertani (LB) broth, as determined by the viability after freeze-drying, was found to be most most effective composition for lyophilization solution among various compositions testitons tested. Rapid freezing with liquid nitrogen also gave the best viability after freeze-drying as compared to samples frozen at-7$0^{\circ}C$ and -2$0^{\circ}C$. The biosensing activities of the cells showed a greater sensitivity when the cells from the expontial phase were freeze-dried. Finally, the optimum temperature for use of the freeze-dried cells in the biodencor field was determined.

• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.525-528
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• 2013

River otter(Lutra lutra) are listed as endangered species and Natural monument in Korea, and this study examined the possibility of extinct of river otter in Hongchon river using with the application of Population Viability Analysis (PVA) technique. In Hongchon river areas population was estimated 9 individuals for the last 1999-2005 years and PVA analysis was done for the next 10 years using the average population of 9. Using the initial population the river otter was estimated 30% of extinct for the next 10 years. This estimation was quite low considering water pollution and construction of highways. Also PVA only used population size lacking in other life history information. Nonetheless river otter population can be in risk of extinction if the current construction of crossovers, cement bank are maintained. Long term information regarding life history needs essential.

• Smart Structures and Systems
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• v.5 no.4
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• pp.397-413
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• 2009

Composite bridges offer many advantages compared to current steel and aluminum bridges. This paper presents the results of a comprehensive on-going research program to develop innovative Diagnostic Prognostic System (DPS) and a structural evaluation of Composite Army Bridge (CAB) system. The DPS is founded on three technologies: optical fiber sensing, remote data transmission, and virtual testing. In developing this system, both laboratory and virtual test were used in different damage scenarios. Health monitoring with DPS entailed comparing live strain data to archived strained data in various bridge locations. For field repairs, a family of composite chords was subjected to simple ramp loads in search of ultimate strength. As such, composite bridge specimens showcased their strengths, heralded the viability of virtual testing, highlighted the efficacy of field repair, and confirmed the merits of health monitoring.

• International Journal of Computer Science & Network Security
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• v.21 no.12
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• pp.9-20
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• 2021

Abstraction applied in computer networking hides network details behind a well-defined representation by building a model that captures an essential aspect of the network system. Two current methods of representation are available, one based on graph theory, where a network node is reduced to a point in a graph, and the other the use of non-methodological iconic depictions such as human heads, walls, towers or computer racks. In this paper, we adopt an abstract representation methodology, the thinging machine (TM), proposed in software engineering to model computer networks. TM defines a single coherent network architecture and topology that is constituted from only five generic actions with two types of arrows. Without loss of generality, this paper applies TM to model the area of network monitoring in packet-mode transmission. Complex network documents are difficult to maintain and are not guaranteed to mirror actual situations. Network monitoring is constant monitoring for and alerting of malfunctions, failures, stoppages or suspicious activities in a network system. Current monitoring systems are built on ad hoc descriptions that lack systemization. The TM model of monitoring presents a theoretical foundation integrated with events and behavior descriptions. To investigate TM modeling's feasibility, we apply it to an existing computer network in a Kuwaiti enterprise to create an integrated network system that includes hardware, software and communication facilities. The final specifications point to TM modeling's viability in the computer networking field.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.191-198
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• 2008

Flow accelerated corrosion (FAC) phenomenon of low alloy carbon steels in nuclear power plant has been known as one of major degradation mechanisms. It has a potential to cause nuclear pipe rupture accident which may directly impact on the plant reliability and safety. Recently, the equipotential switching direct current potential drop (ES-DCPD) method has been developed, by the present authors, as a method to monitor wall loss in a piping. This method can rapidly monitor the thinning of piping, utilizing either the wide range monitoring (WiRM) or the narrow range monitoring (NaRM) technique. WiRM is a method to monitor wide range of straight piping, whereas NaRM focuses significantly on a narrow range such as an elbow. WiRM and NaRM can improve the reliability of the current FAC screening method that is based on computer modeling on fluid flow conditions. In this paper, the measurements by ES-DCPD are performed with signal sensitivity analyses in the laboratory environment for extended period and showed the viability of ES-DCPD for real plant applications.