• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.6
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• pp.573-580
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• 2004

The main goal of this study was to develop a micro-fabrication process for the capacitive micromachined ultrasonic transducer (cMUT). In order to achieve this goal, the former research results of the micro-electro-mechanical system (MEMS) process for the cMUT were analyzed. The membrane deposition, sacrificial layer deposition and etching were found to be a main process of fabricating the cMUT. The optimal conditions for those microfabrication were determined by the experiment. The thickness, uniformity, and residual stress of the $Si_3N_3$ deposition which forms the membrane of the cMUT were characterized after growing the $Si_3N_3$ on Si-wafer under various process conditions. As a sacrificial layer, the growth rate of the $SiO_2$ deposition was analyzed under several process conditions. The optimal etching conditions of the sacrificial layer were analyzed. The microfabrication process developed in this study will be used to fabricate the cMUT.

• Journal of Plant Biotechnology
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• v.43 no.4
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• pp.411-416
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• 2016

Next-generation sequencing allows the identification of mutations responsible for mutant phenotypes by whole-genome resequencing and alignment to a reference genome. However, when the resequenced cultivar/line displays significant structural variation from the reference genome, mutations in the genome regions absent in the reference cannot be identified by simple alignment. In this review, we report the current status and prospects in identification of genes in mutant phenotypes, by using the methods MutMap, MutMap-Gap, and MutMap+. These methods delineate a candidate region harboring a mutation of interest, followed by de novo assembly, alignment, and identification of the mutation within genome gaps. These methods are likely to prove useful for cloning genes that exhibit significant structural variations, such as disease resistance genes of the nucleotide-binding site-leucine rich repeat (NBS-LRR) class.

• Applied Biological Chemistry
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• v.45 no.3
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• pp.138-144
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• 2002

In order to improve the quality of foxtail millet wine, zymological properties by isolated strains from Nuruk were investigated. Saccharomyces sp Y5-1 as brewing yeast, Aspergillus sp. M6-3, Aspergillus awamori 6970, and Aspengillus usamii mut. shirousamii 6959 (KCTC) as saccharifying molds were used, respectively. Acid content, soluble solids, color (b) and alcohol contents were increased during fermentation. Ethanol concentration of millet wine made with Nuruk by Aspergillus awamori 6970 and Aspergillus usamii mut. shirousamii 6959 were higher than the other, 10.6 and 10.1% respectively. Citric acid was only detected on $1{\sim}2$ day starting fermentation. Oxalic acid, lactic acid and acetic acid of millet wine were high in the wine made of Nuruk by Aspergillus usamii mot. shirousamii 6959, Aspergillus awamori 6970 and traditional Nuruk, respectively. During fermentation, glucose and xylose was higher than the others. Xylose was increased, but most of other sugar were decreased during fermentation. Acetone, ethyl acetate, methanol, ethanol, n-propanol, iso-buthanol and iso-amyl alcohol were detected In the wine made with Nuruk by Aspergillus awamori and Aspergillus usamii mut. shirousamii, iso-imyl alcohol and ethanol were high. On sensory evaluation, the wine made with Nuruk by Aspergillus usamii mut. shirousamii was the best on color and taste.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2434-2440
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• 2018

A new type of piezoelectric micromachined ultrasonic transducer (pMUT) with high resonant frequency was developed by using a thin lead zirconate titanate (PZT) as an insulation layer on a floating $10{\mu}m$ silicon membrane. The PZT insulation layer facilitated acoustic impedance matching at active pMUT, leading to a high performance in the acoustic conversion property compared with the transducer using $SiO_2$ insulation layer. The fabricated ultrasonic devices were wirelessly measured by connecting two identical acoustic transducers to two separate ports in a single network analyzer simultaneously. The acoustic wave emitted from a transducer induced a $3.16{\mu}W$ on the other side of the transducer at a distance of 2 cm. The transducer performances in terms of device diameters, PZT thickness, annealings, and different DC polings, etc. were investigated. COMSOL simulation was also performed to predict the device performances prior to fabrication. Based on the COMSOL simulation, the device was fabricated and the results were compared.

• Journal of Sensor Science and Technology
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• v.29 no.1
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• pp.33-39
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• 2020

Typically, photoacoustic images are obtained in water or gelatin because the impedance of these mediums is similar to that of the human body. However, these acoustic mediums can have an additional mass effect that changes the resonance frequency of the transducer. The acoustic radiation impedance in air is negligible because it is very small compared to that of the transducer. However, the high acoustic impedance of mediums such as the human body and water is quite large compared to that of air, making it difficult to ignore. Specifically, in a case where the equivalent mass is very small, such as with a micro-machined ultrasound transducer, the additional mass effects of the acoustic medium should be considered for an accurate resonance frequency design. In this study, a piezoelectric micro-machined ultrasonic transducer (pMUT) was designed to have a resonance frequency of 10 MHz in the acoustic medium of water, which has similar impedance as the human body. At that time, the resonance frequency of the pMUT in air was calculated at 15.2 MHz. When measuring the center displacement of the manufactured pMUT using a laser vibrometer, the resonance frequencies were measured as 14.3-15.1 MHz, which is consistent with the finite element method (FEM) simulation results. Finally, photoacoustic images of human hair samples were successfully obtained using the fabricated pMUT.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.78-87
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• 2018

This paper describes specular reflectance measurements of dielectric plates in three waveguide frequency bands: D-band (110-170 GHz), G-band (140-220 GHz), and J-band (220-325 GHz). The transmit (Tx) part of the proposed specular reflectance measurement system is stationary, while the receive (Rx) part and the material under test (MUT) holder are concentric-rotating with a 2:1 speed ratio for specular reflectance measurements. In specular reflectance measurements, the first step measures the specular reflection coefficients of an MUT and a metal plate on the MUT holder located at the center of the Tx and Rx parts, and the second step calculates the specular reflectance defined by the specular reflection power (i.e., intensity) of the MUT normalized to that of the metal plate. Multiple reflection effects between the Tx and Rx antennas and the MUT on the measured specular reflectance are minimized by averaging out the multiple specular reflectances measured with changing the separation distance between the two antennas by ${\lambda}/8$ intervals. Measurement results of the perpendicular-polarized specular reflectance of commonly used dielectric plates are verified by comparing those with the analytic results and show that the results measured over the overlapped frequency range of the D-/G-bands and at the boundary frequency of the G-/J-bands agree well with the results for the other band, respectively.

• The Korean Journal of Food And Nutrition
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• v.8 no.1
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• pp.6-12
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• 1995

The purpose of this study was to examine the aptitude of wheat flour-Nuluks, for Takju brewing, which were made with Aspergillus oryzae, Rhizopus japonicus or Aspergillus usamii mut. Shirousamii, and to know the way of effective use the Aspergillus oryzae-Nuluk showed high saccharogenic activity, and Rhizopus japonicus-Nuluk high proteolytic activity. When these two Nuluks were combined, the activities of saccharogenic amylase and protease were more balanced. The Takju mash of Aspergillus oryzae-Nuluk was high in acidity and in amino acidity, and that of Rhizopus japonicus-Nuluk high in the content of free sugar, but, that of Aspergillus usamii mut. Shirousamii-Nuluk was low in amino acidity, free sugar and ethanol content. The Takju of Rhizopus japonicus-Nuluk was high in the content of suspended solid and slow in its sedimenting rate, but that of Aspergillus usamii mut. Shirousamii-Nuluk was not. The Takju which was made with combined use of Aspergillus oryzae-Nuluk and Rhizopus japonicus-Nuluk was more balanced in the composition of flavoring ingredients, and was slow in sedimenting rate of suspended solid. Moreover, it gained good result in sunsory evaluation test.

• Korean Architects
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• s.616
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• pp.56-61
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• 2020

• Animal cells and systems
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• v.1 no.3
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• pp.451-455
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• 1997

The effects of nalidixic acid, mitomycin C, and cadmium chloride $(CdCI_2)$ on the activity of 8-hydroxyguanine $(oh^8Gua)$ endonuclease, a DNA repair enzyme for oxidatively modified guanine, $(oh^8Gua$ were studied. Nalidixic acid and mitomycin C, typical inducers of the S0S DNA repair response in E. coli, showed different effects. Nalidixic acid raised the activity of this enzyme, but mitomycin C did not show such an effect. Cadmium chloride also induced the enzyme activity, These results show that the expression of $oh^8$ Gua endonuclease is regulated by multiple factors and can be induced under stressful conditions. In an attempt to demonstrate the importance of this enzyme in defense against DNA damage and mutagenesis, we also characterized mutM mutant for its oh8 Gua endonuclease activity. The mutM mutant showed no detectable $oh^8$ Gua endonuclease activity, unlike its wild type showing high activity. In addition, paraquat, a superoxide producing compound, failed to elevate $oh^8Gua$ endonuclease activity in this mutant. These results suggest that the mutM gene is identical to the $oh^8Gua$ endonuclease gene of E. coli. Taken together with previous reports, these results suggest that $oh^8Gua$ endonuclease plays a crucial role in the protection of aerobically growing organisms from threats of oxidative DNA damage and mutation.

• BMB Reports
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• v.40 no.6
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• pp.1021-1027
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• 2007

We demonstrated the genetic polymorphism of aldehyde oxidase (AO) in Donryu strain rats: the ultrarapid metabolizer (UM) with nucleotide mutation of (377G, 2604C) coding for amino acid substitution of (110Gly, 852Val), extensive metabolizer (EM) with (377G/A, 2604C/T) coding for (110Gly/Ser, 852Val/Ala), and poor metabolizer (PM) with (377A, 2604T) coding for (110Ser, 852Ala), respectively. The results suggested that 377G > A and/or 2604C > T should be responsible for the genetic polymorphism. In this study, we constructed an E. coli expression system of four types of AO cDNA including Mut-1 with (377G, 2604T) and Mut-2 with (377A, 2604C) as well as naturally existing nucleotide sequences of UM and PM in order to clarify which one is responsible for the polymorphism. Mut-1 and Mut-2 showed almost the same high and low activity as that of the UM and PM groups, respectively. Thus, the expression study of mutant AO cDNA directly revealed that the nucleotide substitution of 377G > A, but not that of 2604C > T, will play a critical role in the genetic polymorphism of AO in Donryu strain rats. The reason amino acid substitution will cause genetic polymorphism in AO activity was discussed.