• Journal of Microbiology and Biotechnology
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• v.21 no.6
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• pp.567-573
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• 2011

We investigated the phylogenetic diversity of ammoniaoxidizing bacteria (AOB) in Yellow Sea continental shelf sediment by the cloning and sequencing of PCR-amplified amoA and 16S rRNA genes. Phylogenetic analysis of the amoA-related clones revealed that the diversity of AOB was extremely low at the study site. The majority (92.7%) of amoA clones obtained belonged to a single cluster, environmental amoA cluster-3, the taxonomic position of which was previously unknown. Phylogenetic analysis on AOB-specific 16S rRNA gene sequences also demonstrated a very low diversity. All of the cloned 16S rRNA gene sequences comprised a single phylotype that belonged to the members of uncultured Nitrosospira cluster-1, suggesting that AOB belonging to the uncultured Nitrosospira cluster-1 could carry amoA sequences of environmental amoA cluster-3.

• Journal of Aerospace System Engineering
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• v.14 no.6
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• pp.44-57
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• 2020

The ICAO AMO global recognition system will be instituted in 2024, with the aim of reducing the certification and surveillance burden on aviation authorities and approved maintenance organizations (AMOs). If the domestic AMO certification and surveillance system is internationally recognized through this system, it may facilitate the rapid development of the domestic MRO industry in South Korea. To ensure international recognition of the domestic AMO system, the AMO surveillance and regulation system must be improved. This study reviewed ICAO policies, standards, guidelines, and leading aviation authorities' regulations and systems with regard to maintenance organization certification and surveillance, and a comparative analysis with the domestic system was conducted. From this, gaps in aviation safety inspection personnel training, qualification, and surveillance were identified, and measures for improving inspection personnel training and organization certification and surveillance system maintenance were elucidated to preemptively respond to the ICAO AMO global recognition system.

• Korean Journal of Microbiology
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• v.50 no.2
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• pp.164-168
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• 2014

The ecosystem of the Arctic region has been increasingly affected by global warming. Archaeal ammonia monooxygenase alpha subunit coding gene (amoA) which is a key enzyme for nitrification was used to investigate the effect of runoff water of ice melt on microbial community of nitrogen cycle. The archaeal amoA genes at coastal area of Svalbard, Arctic region were PCR-amplified and sequenced after clone library construction. Analysis of archaeal amoA gene clone libraries suggested that the station 188 which is in the vicinity to the area of runoff water harbor lower ammonia-oxidizing archaeal diversity than the station 176 and 184. The average amino acid sequence identity within all archaeal amoA gene clones was 94% (with 91% nucleotide sequence identity). While all the clones of the station 188 were affiliated with Nitrosoarchaeaum clade containing strains isolated from low-salinity and terrestrial environments, about 45% of total clones of the station 176 and 184 were related to marine Nitosopumilus clade. Interestingly, other typical archaeal amoA gene clones of thaumarchaeal I.1b clade frequently retrieved from terrestrial environments was identified at station 188. Microbial community of nitrogen cycle in marine sediment might be affected by input of sediments caused by runoff glacier melt waters.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.232-235
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• 2007

Mesophilic Crenarchaeota have been known to be predominant among ammonia-oxidizing microorganisms in terrestrial and marine environments. In this study, we determined the archaeal phylotypes carrying specific amoA by combining digital PCR and multiplex-nested PCR. Analysis of samples in which amoA and 16S rRNA gene were amplified showed that amoA gene diversity was relatively higher than that of 16S rRNA gene. Nitrifying archaeal group I.1a was dominant over I.1b group of crenarchaota and euryarchaeota. This approach could be applied for interrelating a functional gene to a specific phylotype in natural environments.

• Journal of Aerospace System Engineering
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• v.10 no.2
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• pp.27-33
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• 2016

For the continued airworthiness of aviation products, aviation authority requires that every manufacturer should provide ICA(Instruction of Continued Airworthiness) to their users, and the users should follow it by themselves or using another approved maintenance agent. To reduce the cost and improve performance quality of maintenance activities, lots of users tries to outsource this job. To perform maintenance or repair of other owned air products, an air carrier and aviation maintenance companies should obtain AMO(approval of maintenance organization). It means AMO is a postulation to enter MRO(Maintenance Repair and Overhaul) market. For that, this paper discusses the comparison of requirements and procedures of AMO system between Korea and US to help understand the AMO system, and then, tries to point out what improvement should be made to Korean AMO system to be more effective, efficient and safe.

• Applied Biological Chemistry
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• v.11
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• pp.173-184
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• 1969

To elucidate the effect of Amo-1618(4-hydroxyl-5-isopropyl-2-methlphenyl trimethyl ammonium chloride, 1-piperidine carboxylate) known as a kind of growth retardant, on the growth, grain yield, increasing the efficiency of nitrogen fertilizer, behavior of mineral nutritions and the rate of phosphorus utilization, this experiment was conducted pot culture method in a vinyl house. Two nitrogen level, namely, practical nitrogen level(1 N) and three times nitrogen level(3 N) was made and labelled double-calcium-superphosphate $Ca(H_2P^{32}O_4)_2.\;2H_2O)$ as a source of radioactive phosphorus(P-32) was employed $80\;{\mu}c/pot$, respectively. Rice seedlings, variety 'Suwon No. 82', was transplanted to a 1/50,000 a china pot on June 13 in 1968. For treatment, at early stage of tillering, 10,000 ppm solution of Amo-1618 was foliar sprayed only one time. The Duncan's new mutiple-range test was adopted for statistical analysis evaluating experimental data at 5% level significance. The results obtained may be summarized as follows; 1) No significant difference was found among the treatments in plant height, but in plot of Amo-1618 treatment and 3 N level, number of tillers was significantly increased than that of others. 2) Weight of 10,000 kernels and seed-setting rate was also remarkably increased in same treatment above. 3) Grain yield per pot was significantly increased in Amo-1618 and 3 N level application. This results seemed to be due to the increased the factors on the yield. 4) Contents of nitrogen and phosphorus per cent in the grain was likewise increased in Amo-1618 and 3 N application. There is, however, no difference among treatments in the content of nitrogen and phosphorus in the leaves and culms of rice plants. 5) On the other hand, the contents of potassium and magnesium, no distinctly tendeny showed among treatments. 6) The rate of phosphorus utilization was significantly increased in the plot of Amo-1618 and 3 N application.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.4
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• pp.33-44
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• 2022

As the majority of Korean MRO demand is outsourced overseas, AMO by major foreign authorities is required to promote the Korean MRO industry to keep Korean MRO demand on shore. This study aims to promote consulting for AMO (obtaining repair station certification) by U.S. Federal Aviation Administration (FAA) for Korean maintenance companies. We analyzed AMO process, studied various industry cases, developed a model for AMO consulting, and identified core competencies for consultants. We suggested a five-step modified Milan model to apply AMO consulting process. We identified seven core competencies (ethics, communications, problem-solving, technical, relationship, resource management, organizational understanding) both social and technical for consultants. Additionally, we text analyzed more than 260 FAA AMO consultant resumes on Linkedin and interpreted frequent words (airline, audit, inspector, DER, regulation, ISO, system) to their competencies. This study contributes to promote consulting for the Korean MRO industry to be recognized by FAA and to develop the Korean MRO industry.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1187-1196
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• 2013

Global warming will have far-reaching effects on our ecosystem. However, its effects on Antarctic soils have been poorly explored. To assess the effects of warming on microbial abundance and community composition, we sampled Antarctic soils from the King George Island in the Antarctic Peninsula and incubated these soils at elevated temperatures of $5^{\circ}C$ and $8^{\circ}C$ for 14 days. The reduction in total organic carbon and increase in soil respiration were attributed to the increased proliferation of Bacteria, Fungi, and Archaea. Interestingly, bacterial ammonia monooxygenase (amoA) genes were predominant over archaeal amoA, unlike in many other environments reported previously. Phylogenetic analyses of bacterial and archaeal amoA communities via clone libraries revealed that the diversity of amoA genes in Antarctic ammonia-oxidizing prokaryotic communities were temperature-insensitive. Interestingly, our data also showed that the amoA of Antarctic ammonia-oxidizing bacteria (AOB) communities differed from previously described amoA sequences of cultured isolates and clone library sequences, suggesting the presence of novel Antarctic-specific AOB communities. Denitrification-related genes were significantly reduced under warming conditions, whereas the abundance of amoA and nifH increased. Barcoded pyrosequencing of the bacterial 16S rRNA gene revealed that Proteobacteria, Acidobacteria, and Actinobacteria were the major phyla in Antarctic soils and the effect of short-term warming on the bacterial community was not apparent.

• Imaging Science in Dentistry
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• v.47 no.1
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• pp.33-37
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• 2017

Purpose: This study aimed to evaluate the prevalence of Haller cells and accessory maxillary ostium (AMO) in cone-beam computed tomography (CBCT) images, and to analyze the relationships among Haller cells, AMO, and maxillary sinusitis. Materials and Methods: Volumetric CBCT scans from 201 patients were retrieved from our institution's Digital Imaging and Communications in Medicine archive folder. Two observers evaluated the presence of Haller cells, AMO, and maxillary sinusitis in the CBCT scans. Results: AMO was observed in 114 patients, of whom 27 (23.7%) had AMO exclusively on the right side, 26 (22.8%) only on the left side, and 61 (53.5%) bilaterally. Haller cells were identified in 73 (36.3%) patients. In 24 (32.9%) they were present exclusively on the right side, in 17 (23.3%) they were only present on the left side, and in 32 (43.8%) they were located bilaterally. Of the 73 (36.3%) patients with Haller cells, maxillary sinusitis was also present in 50 (68.5%). On using chi-square test, a significant association was observed between AMO and maxillary sinusitis in the presence of Haller cells. Conclusion: Our results showed AMO and Haller cells to be associated with maxillary sinusitis. This study provides evidence for the usefulness of CBCT in imaging the bony anatomy of the sinonasal complex with significantly higher precision and a smaller radiation dose.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.629-636
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• 2010

A simple, rapid method for determining amoxicillin (AMO) and ampicillin (AMP) in aquatic products (flatfish, salmon, shrimp, tilapia, and yellow croaker) was evaluated. For quantification, the AMO and AMP ions at m/z 348.9 and 105.9, respectively, were selected. The limit of detection (LOD) and limit of quantification (LOQ) for detecting AMO were 0.09 and $0.25\;{\mu}g/L$, respectively. The respective values for AMP were 0.02 and $0.05\;{\mu}g/L$. After $100\;{\mu}g/L$ AMO treatment, the level decreased 10% after 7 days at $5^{\circ}C$, while it decreased 20% at $25^{\circ}C$. After 7 days, 94.9.100% of $100\;{\mu}g/L$ AMP remained after storage at $5^{\circ}C$, while 62.3.100% remained after storage at $25^{\circ}C$. Using the food code method, the recovery of AMO ranged from 64.1.92.0% and that of AMP from 44.8.86.2%. With a protein centrifugation method, the recovery of AMO ranged from 39.8.87.9% and that of AMP from 78.0.98.1%. With liquid-liquid extraction, the recovery of AMO ranged from 36.5.88.3% and that of AMP from 31.8.75.1%.