• Korean Journal of Ecology and Environment
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• 제38권2호통권112호
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• pp.249-260
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• 2005

Dynamics of phytoplankton community were monthly examined at two sites in Lake Juam from January to December 2003. One site is located near the Dam, an intake tower, where obtain a drinking water resource, the other site is located in the shallow region, Mundeok-bridge, the upstream or effluent part of lake. During the study, there made little the differences in physicochemical factors between two sites, but numbers of species and standing crops of phytoplankton differ remarkably. Totally, 41% of green algae and 35.8% of diatoms were comprised of total phytoplankton species, while 46.3% of dinoflagellates and 27.6% of cyanobacteria contributed in total standing crops of Phytoplankton community. Cyanobacterium Microcystis aeruginora and diatom Fragilaria crotonensis dominated the Dam site during a warm season, while dinoflagellates Peridinium bipes and Asterionella formosa were at the shallow region during a cold season, respectively. According to the CCA analysis, dissolved oxygen, chemical oxygen demand and total phosphate strongly affected the growth of P. bipes with low water temperature. In addition, the increment of total nitrogen and water temperature affected biomass of a cyanobacterium M. aeruginosa. Collectively, it may suggest that the majority of annual primary production of Lake Juam is covered by two dominant species Peridinium bipes in cold season and Microcystis aeruginosa in warm season.

• Korean Journal of Ecology and Environment
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• 제38권1호통권110호
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• pp.30-44
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• 2005

To investigate the flora and vegetation structure of vascular plants in the littoral zone of Paldang Reservoir, from April, 2003 to April 2004, nine sampling sites were selected. Along the Paldang Reservoir, 128 taxa, consisted of 51 families and 96 genera, were identified, among them, hydrophytes were confirmed as 38 taxa, which was comprised 29.7% to total taxa, whereas hygrophytes were 44 taxa and terrestrial plants were 46 taxa. Emergent hydrophytes consists of 21 taxa, including Phragmites australis and Typha angustifolia, and next, submerged hydrophytes were 8 taxa. However, the kinds and vegetation area of submerged hydorphytes were reduced compared to previous studies. In the littoral zone of Paldang Reservoir, the aquatic vegetation was widely developed near Dumulmori, Yangsuri, and Kwangdong Bridge, downstream of Kyungancheon. The average number of hydrophyte per sampling sites were 2.7 taxa, whereas hygrophytes were 2.5, and land plants were 1.8. In addition, the hydrophytes in the littoral zone of Paldang Reservoir showed the typical vertical zonation pattern like a natural swamp. These results mean that the littoral zone of Paldang Reservoir has the typical characteristics of aquatic plant ecosystem.

• Journal of the Korean Geotechnical Society
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• 제28권7호
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• pp.67-75
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• 2012

This paper addresses the size effect of shallow foundation settlement in very dense weathered granite soil commonly encountered in bridge foundation. Load-settlement curves measured from the plate load tests of 5 different plate sizes in 2 sites were analyzed. The test results showed that the ground beneath the plate was considered not to reach the failure state and the settlement continuously increased proportionately as load increased. The result implies that settlement would govern the stability or serviceability of foundation on very dense weathered soil. The size effect is expressed as a relationship of subgrade reaction modulus to the size of plate. Compared with the previous relationships, the size effect in this result was more prominent and indicated that settlement prediction using the previous method could possibly underestimate the settlement of foundation in dense weathered granite soil.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제35권1호
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• pp.19-29
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• 2015

As the half-depth precast concrete decks are increasingly applied to the construction sites, researches on connection details have been increased. For design of concrete bridge deck with half-depth precast panels, it is required to provide appropriate details of transverse loop joints between panels. In this paper, the structural performance of precast decks was evaluated to investigate continuity of the proposed loop joint details. From the results, the validity of the joints for the continuity of deck was observed in the aspect of flexural strength and crack control. The ultimate strength increased 1.52 times as the reinforcement spacing in the joint was reduced. In terms of crack control, direct crack width calculation for the loop joint showed appropriate results comparing with measured crack width.

• Journal of the Korean Society of Safety
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• 제21권4호
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• pp.73-84
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• 2006

Standard safety management cost system was established in 1988 as a decree Number of 88-13, first time. And then, it has been revised fourteen times, up to now. A lot of practical investigations have been made for the revision but many problems at sites are continued to be put out so that it should be revised. This study is to find out hazard level of each work kinds through questionnaire and interview and investigate analyze the status which standard safety management costs have been used. Also, this study is to show reasonable rates of standard safety management costs in construction industry and to set up countermeasures against those problem after reviewing its status in korea with in Japan and Europe. Budget and actually performed amount of safety management costs in this study are investigated. costs for temporary work which is clarified in Japan is collected in order to compare domestic cost rate with Japanese one related to the total project amount. This study is to investigate eleven project kinds of domestic system, first, and to investigate eleven items of apartment bldg, office, civil work such as bridge, tunnel, dam, plant etc, secondly. Additionally, three items of gymnasium, railway, particular steel tower are investigated in this study. Also this study is to investigate and analyze performed costs of presently processing worker finished work so that it shows a new reasonable rate against standard safety management costs in construction industry, in order to make basical data and material to be systemized.

• Journal of Microbiology and Biotechnology
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• 제25권11호
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• pp.1827-1834
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• 2015

The SMG1 lipase from Malassezia globosa is a newly found mono- and diacylglycerol (DAG) lipase that has a unique lid in the loop conformation that differs from the common alpha-helix lid. In the present study, we characterized the contribution of three residues, L103 and F104 in the lid and F278 in the rim of the binding site groove, on the function of SMG1 lipase. Site-directed mutagenesis was conducted at these sites, and each of the mutants was expressed in the yeast Pichia pastoris, purified, and characterized for their activity toward DAG and p-nitrophenol (pNP) ester. Compared with wild-type SMG1, F278A retained approximately 78% of its activity toward DAG, but only 11% activity toward pNP octanoate (pNP-C8). L103G increased its activity on pNP-C8 by approximately 2-fold, whereas F104G showed an approximate 40% decrease in pNP-C8 activity, and they both showed decreased activity on the DAG emulsion. The deletion of 103-104 retained approximately 30% of its activity toward the DAG emulsion, with an almost complete loss of pNP-C8 activity. The deletion of 103-104 showed a weaker penetration ability to a soybean phosphocholine monolayer than wild-type SMG1. Based on the modulation of the specificity and activity observed, a pNP-C8 binding model for the ester (pNP-C8, N102, and F278 form a flexible bridge) and a specific lipid-anchoring mechanism for DAG (L103 and F104 serve as "anchors" to the lipid interface) were proposed.

• Microbiology and Biotechnology Letters
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• 제46권2호
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• pp.135-144
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• 2018

The rapid increase in number and diversity of Extended Spectrum ${\beta}$-Lactamases (ESBLs) producing Enterobacteriaceae in natural aquatic environment is a major health concern worldwide. This study investigates abundance and distribution of ESBL producing multidrug resistant Enterobacteriaceae and molecular characterization of ESBL genes among isolates from highly polluted stretch of river Yamuna, India. Water samples were collected from ten different sites distributed across Delhi stretch of river Yamuna, during 2014-15. A total of 506 non duplicate Enterobacteriaceae isolates were obtained. Phenotypic detection of ESBL production and antibiotic sensitivity for 15 different antibiotics were performed according to CLSI guidelines (Clinical and Laboratory Standard Institute, 2015). A subset of ESBL positive Enterobacteriaceae isolates were identified by 16S rRNA gene and screened for ESBL genes, such as $bla_{CTX-M}$, $bla_{TEM}$ and $bla_{OXA}$. Out of 506 non-duplicate bacterial isolates obtained, 175 (34.58%) were positive for ESBL production. Susceptibility pattern for fifteen antibiotics used in this study revealed higher resistance to cefazolin, rifampicin and ampicillin. A high proportion (76.57%) of ESBL positive isolates showed multidrug resistance phenotype, with MAR index of 0.39 at Buddha Vihar and Old Delhi Railway bridge sampling site. Identification and PCR based characterization of ESBL genes revealed the prevalence of $bla_{CTX-M}$ and $bla_{TEM}$ genes to be 88.33% and 61.66%, respectively. Co-occurrence of $bla_{CTX-M}$ and $bla_{TEM}$ genes was detected in 58.33% of the resistant bacteria. The $bla_{OXA}$ gene was not detected in any isolates. This study highlights deteriorating condition of urban aquatic environment due to rising level of ESBL producing Enterobacteriaceae with multidrug resistance phenotype.

• The Journal of Advanced Prosthodontics
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• 제8권5호
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• pp.354-362
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• 2016

PURPOSE. The trueness and precision of acquired images of intraoral digital scanners could be influenced by restoration type, preparation outline form, scanning technology and the application of power. The aim of this study is to perform the comparative evaluation of the 3-dimensional reproducibility of intraoral scanners (IOSs). MATERIALS AND METHODS. The phantom containing five prepared teeth was scanned by the reference scanner (Dental Wings) and 5 test IOSs (E4D dentist, Fastscan, iTero, Trios and Zfx Intrascan). The acquired images of the scanner groups were compared with the image from the reference scanner (trueness) and within each scanner groups (precision). Statistical analysis was performed using independent two-samples t-test and analysis of variance (${\alpha}=.05$). RESULTS. The average deviations of trueness and precision of Fastscan, iTero and Trios were significantly lower than the other scanners. According to the restoration type, significantly higher trueness was observed in crown and inlay than in bridge. However, no significant difference was observed among four sites of preparation outline form. If compared by the characteristics of IOS, high trueness was observed in the group adopting the active triangulation and using powder. However, there was no significant difference between the still image acquisition and video acquisition groups. CONCLUSION. Except for two intraoral scanners, Fastscan, iTero and Trios displayed comparable levels of trueness and precision values in tested phantom model. Difference in trueness was observed depending on the restoration type, the preparation outline form and characteristics of IOS, which should be taken into consideration when the intraoral scanning data are utilized.

• Imaging Science in Dentistry
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• 제39권1호
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• pp.19-25
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• 2009

Purpose: To longitudinally observe the healing process of extracted socket and the alterations of the residual ridge in healthy adult dogs using cone beam CT (CBCT). Materials and Methods: The mandibular premolars of two beagle dogs were removed and the extraction sites were covered with the gingival tissue. CBCTs (3D X-ray CT scanner, Alphard vega, Asahi Co.) were taken at baseline and at 1 week interval for 12 weeks. Radiographic density of extracted wounds was measured on normalized images with a custom-made image analysis program. The amount of alveolar crestal resorption after the teeth extraction was measured with a reformatted three-dimensional image using CBCT. Bony healing pattern of extracted wound of each group was also longitudinally observed and analyzed. Results: Dimensional changes occurred during the first 6 weeks following the extraction of dogs' mandibular premolars. The reduction of the height of residual ridge was more pronounced at the buccal than at the lingual aspect of the extraction socket. Radiographic density of extracted wounds increased by week 4, but the change in density stabilized after week 6. New bone formation was observed at the floor and the peripheral side of extracted socket from week 1. The entrance of extracted socket was sealed by a hard-tissue bridge at week 5. Conclusion: The healing process of extracted wound involved a series of events including new bone formation and residual ridge resorption.

• Explosives and Blasting
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• 제25권2호
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• pp.71-78
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• 2007

In many cases of underwater blasting in South Korea, the special blasting is mainly used for deepening harbor, installing gas pipes, or well blasting to build a bridge. The procedure of well blasting is almost same with shaft blasting, but the difference is that water is filled in before blasting. In case of deepening blasting under water, the first step like drilling, arranging explosives, and wire connection is done on a barge, then the next step such as charging and tamping is accomplished under water by expert divers. Therefore, underwater blasting needs precise and exact plan before blasting. In this paper, authors would like to introduce a case of underwater blasting for deepening the Busan new port with emulsion explosives and non-electric detonators in order to get some of 8,500TEU out sized container vessels entered into the port and to make safe. Considering environment and vibration, the blasting was controlled to minimized the damage to the lighthouse nearby. It will be great help to many other blasting sites where emulsion explosives and non-electric detonators are used for underwater blasting through this case.