• Structural Engineering and Mechanics
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• v.85 no.3
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• pp.353-367
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• 2023

An extended parametric study based on nonlinear finite element analyses is performed to assess the key factors affecting the shear behaviour of exterior beam-column joints of unbraced reinforced concrete frames. Extensive results are presented, the major conclusion being that the few shear behaviour models for exterior reinforced concrete beam-column joints available in the literature do not properly account for some of the most influential factors. The present results are also compared with recently published results for interior joints, showing that while some factors have a similar influence on interior and exterior joints others are relevant for only one of these types of joints. This also confirms, numerically, that some resisting mechanisms of exterior joints differ from those of interior joints.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.86-90
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• 2009

The definition of edible ice is frozen water for the use of food manufacturing, processing, or cooking, as well as for the direct eating. It has been reported that in the process of ice manufacturing and its selling, edible ice is contaminated with some microorganisms, which causes food poisoning and gastroenteritis. It was shown that besides in the edible ice, germ growth caused by various reasons occurred in the mineral water, tap water, water filtering system, and water purifier. With public awareness, in order to examine the sanitary conditions of edible ice in the Northern area of Daegu metropolitan city, 15 places were randomly selected. As a result, 14 places were found to be contaminated with microorganisms. After incubating on the Brain Heart Infusion (BHI) agar plate, 80% of Gram-negative bacilli, 17% of Gram-positive cocci, and 3% of Gram-negative cocci were cultured. Enterobacter cloacae, Chryseomonas luteola, Pantoea spp., Klebsiella pneumoniae, Acinetobacter baumannii, Acinetobacter calcoaceticus or Providencia rettgeri were detected. Gram-positive cocci cultured in BHI agar plate from 5 specimens were identified as Staphylococcus aureus or Staphylococcus xylosus, which is well known bacteria causing strong food poisoning. This present paper raises questions on the importance and awareness of sanitary conditions of edible ice and the identification of pathogenic microorganisms living in the edible ice in relation to their distribution. The examination of sanitary conditions of edible ice in other areas in Daegu seems to be also needed to find out if there are similar cases.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.164-170
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• 2007

The concept of innate immunity in insects which refers to the first line of host defense constitutes the humoral and cellular components which are involved in recognition and actively participate in the elimination of the intruding foreign micro- or macro-organisms. Several recent studies suggest that juvenile hormone (JH) modulates the cellular immune reactions in response to pathogen. In this study, pyriproxyfen (a JH agonist as an insect growth regulator) was tested in its any inhibitory effect on the immune reactions of the beet armyworm, Spodoptera exigua. To this end, five different hemocyte morphotypes of final instar S. exigua were identified by phase contrast microscopy. Plasmatocytes and granular cells, which constitute about 90% of the total hemocyte count, were prominently distinguished based on their basophilic/acidophilic nature using Giemsa stain. The role of pyriproxyfen on the functional ability of hemocytes was analyzed using FITC-labeled Providencia vermicola for the phagocytic potential of the hemocytes. Both granular cells and plasmatocytes exhibited phagocytosis behavior. Pyriproxyfen significantly inhibited the phagocytosis of both cell types, proposing its novel action as an immunosuppressant.

• Korean Journal of Veterinary Service
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• v.25 no.1
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• pp.15-22
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• 2002

This experiment was carried out to investigate the changes of egg qualify during storage in order to find out the proper storage condition. Fresh eggs were stored at cold condition ($5^{\circ}C$, relative humidity ; RH :$65\pm$3%) and room condition($25^{\circ}C$, RH :$40\pm$3%) during 10 weeks and examined microbiological quality, weight loss and interior quality periodically. Weight loss was indicated 17.93% at room condition and 2.56% at cold condition. The pH of egg white and yolk were increased from 7.94 to 9.03(average 13.72%) and from 6.16 to 6.57(average 6.65%) at cold condition and from 7.94 to 9.54(average 20.15%) and from 6.16 to 6.90(average 12.01%) at room condition respectively. But pH of egg white and yolk did not showed significant difference between before molting and after molting. Haugh unit was decreased from 82.0 to <30 at room condition after 3 weeks. The most frequent bacteria isolated were E coli, Staphylococcus leutus, S saprophyticus, Citrobacter freundii, Klebsiella oxytoca, Providencia rettgeri, and Pontoea spp. It was recommended that shelf life of unrefrigerated eggs would not be longer than 21 days at room temperature in summer.

• Structural Engineering and Mechanics
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• v.76 no.3
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• pp.337-354
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• 2020

Reinforced concrete beam-column (RCBC) joints of laterally loaded unbraced frames are sometimes controlled by their shear behavior. This behavior relies on multiple and interdependent complex mechanisms. There are already several studies on the influence of some parameters on the shear strength of reinforced concrete joints. However, there are no studies methodically tackling all the most relevant parameters and quantifying their influence on the overall joint behavior, not just on its shear strength. Hence, considering the prohibitive cost of a comprehensive parametric experimental investigation, a nonlinear finite element analysis (NLFEA) was undertaken to identify the key factors affecting the shear behavior of such joints and quantify their influence. The paper presents and discusses the models employed in this NLFEA and the procedure used to deduce the joint behavior from the NLFEA results. Three alternative, or complementary, quantities related to shear are considered when comparing results, namely, the maximum shear stress supported by the joint, the secant shear stiffness at maximum shear stress and the secant shear stiffness in service conditions. Depending on which of these is considered, the lower or higher the relevance of each of the six parameters investigated: transverse reinforcement in the joint, intermediate longitudinal bars and diagonal bars in the column, concrete strength, column axial load and confining elements in transverse direction.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.621-629
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• 2019

In this study we attempted to screen bacteria and fungi that generate electricity while treating wastewater using optimized double-chamber microbial fuel cell (MFC) system parameters. Optimization was carried out for five best exoelectrogenic isolates (two bacteria and three fungi) at pH values of 6.0, 7.5, 8.5, and 9.5, and temperatures of 30, 35, 40, and 45℃; the generated power densities were measured using a digital multimeter (DT9205A). The isolates were identified using molecular characterization, followed by the phylogenetic analysis of isolates with known exoelectrogenic microorganisms. The bacterium, Proteus species, N6 (KX548358.1) and fungus, Candida parapsilosis, S10 (KX548360) produced the highest power densities of 1.59 and 1.55 W/m² (at a pH of 8.5 and temperatures of 35 and 40℃) within 24 h, respectively. Other fungi-Clavispora lusitaniae, S9 (KX548359.1) at 40℃, Clavispora lusitaniae, S14 (KX548361.1) at 35℃-and bacterium-Providencia species, N4 (KX548357.1) at 40℃-produced power densities of 1.51, 1.46, and 1.44 W/m², respectively within 24 h. The MFCs achieved higher power densities at a pH of 8.5, temperature of 40℃ within 24 h. The bacterial isolates have a close evolutionary relationship with other known exoelectrogenic microorganisms. These findings helped us determine the optimal pH, temperature, evolutionary relationship, and exoelectrogenic fungal species other than bacteria that enhance MFC performance.

• Structural Engineering and Mechanics
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• v.64 no.5
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• pp.641-652
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• 2017

In general, conventional analysis and design of reinforced concrete (RC) frame structures overlook the role of beam-column (RCBC) joints. Nowadays, the rigid joint model is one of the most common for RCBC joints: the joint is assumed to be rigid (unable to deform) and stronger than the adjacent beams and columns (does not fail before them). This model is popular because (i) the application of the capacity design principles excludes the possibility of the joint failing before the adjacent beams and (ii) many believe that the actual behaviour of RCBC joints designed according to the seismic codes produced mainly after the 1980s can be assumed to be nominally rigid. This study investigates the relevance of the deformation of RCBC joints in a standard pushover analysis at several levels: frame, storey, element and cross-section. Accordingly, a RC frame designed according to preliminary versions of EN 1992-1-1 and EN 1998-1 was analysed, considering the nonlinear behaviour of beams and columns by means of a standard sectional fibre model. Two alternative models were used for the RCBC joints: the rigid model and an explicit component based nonlinear model. The effect of RCBC joints modelling was found to be twofold: (i) the flexibility of the joints substantially increases the frame lateral deformation for a given load (30 to 50%), and (ii) in terms of seismic performance, it was found that joint flexibility (ii-1) appears to have a minor effect on the force and displacement corresponding to the performance point (seismic demand assessed at frame level), but (ii-2) has a major influence on the seismic demand when assessed at storey, element and cross-section levels.

• Korean Journal of Environmental Biology
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• v.38 no.3
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• pp.433-449
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• 2020

Nine fish and one clam species were collected from freshwater environments in Korea, including four lakes, two streams, and the Nakdong River, to investigate the host-associated bacteria. Hundreds of bacterial strains were isolated from the samples using a cell sorter and a dilution plating method. After identification of the bacterial strains using 16S rRNA gene sequences, 42 strains with greater than 98.7% sequence similarity with validly published species were determined to be unrecorded bacterial species in Korea. These strains were phylogenetically diverse and assigned to four phyla, six classes, 17 orders, 27 families, and 32 genera. At the genus level, the unrecorded species were classified as Corynebacterium, Mycobacterium, Mycolicibacterium, Gordonia, Williamsia, Modestobacter, Brachybacterium, Sanquibacter, Arthrobacter, and Mycolicibacterium of the class Actinobacteria; Empedobacter, and Flavobacterium of the class Flavobacteriia; Fictibacillus, Psychrobacillus, Cohnella, Paenibacillus, Rummeliibacillus, Enterococcus, and Vagococcus of the class Bacilli; Aquamicrobium, Paracoccus, and Sphingomonas of the class Alphaproteobacteria; Achromobacter, Delftia, and Deefgea of the class Betaproteobacteria; and Aeromonas, Providencia, Yersinia, Marinomonas, Acinetobacter, and Pseudomonas of the class Gammaproteobacteria. The 42 unrecorded species were subjected to further taxonomic characterization using gram staining, cellular and colony morphological determination, biochemical analyses, and phylogenetic analyses. This paper provides detailed descriptions of the 42 previously unrecorded bacterial species.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.421-427
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• 2016

We aim to offer basic materials about infection management through conducting bacterial contamination test about general radiography equipment and CT equipment installed in ER of three general hospitals with 100 sickbeds or more located in Gyeongsangbuk-do Province, and suggest management plan. It had been conducted from 1st December 2015 to 31st December, and objects were general radiography equipment and CT equipment of emergency room located in Gyeongsangbuk-do Province. For general radiography equipment, sources were collected from 4 places such as upper side of control box which employees use most, upper side of exposure button, whole upper side of table which is touching part of patient's skin, upper side of stand bucky's grid, and where patients put their jaws on. For CT equipment, sources were collected from 3 places such as upper side of control box which radiography room employees use most, X-ray exposure button, whole upper side of table which is touching part of patient's skin, and gantry inner. Surface contamination strain found at general radiography equipment in emergency room of radiology are Providencia stuartii(25%), Stenotrophomonas maltophilia(18%), Enterobacter cloacae(8%), Pseudomonas species(8%), Staphylococcus epidermidis(8%), Gram negative bacilli(8%), and ungrown bacteria at incubator after 48 hours of incubation (67%) which is the biggest. Most bacteria were found at upper side of stand bucky-grid and stand bucky of radiology's general radiography equipment, and most sources of CT equipment were focused at patient table, which means it is contaminated by patients who have various diseases, and patients who have strains with decreased immunity may get severe diseases. Thus infection prevention should be made through 70% alcohol disinfection at both before test and after test.

• Journal of Life Science
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• v.28 no.11
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• pp.1301-1315
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• 2018

We purified an antimicrobial peptide from the acidified hemocyte extract of Mytilus coruscus by $C_{18}$ reversed-phase high-performance liquid chromatography (RP-HPLC). The peptide was 4041.866 Da based on matrix-assisted laser desorption ionization time-of-flight mass spectrophotometer (MALDI-TOF/MS) and the 25 amino acids of the N-terminus sequence were identified. Comparison of this sequence of the purified peptide with the N-terminus sequences of other antimicrobial peptides revealed 100% identity with the mytilin B precursor of Mytilus coruscus. We also identified a 312 bp open-reading frame (ORF) encoding 103 amino acids based on the obtained amino acid residues. The nucleotide sequence of this ORF and the amino acid sequence also revealed 100% identity with the mytilin B precursor of Mytilus coruscus. We synthesized two antimicrobial peptides with an alanine residue in the C-terminus, and designated them mytilin B1 and B2. These two antimicrobial peptides showed antimicrobial activity against gram-positive bacteria, including Bacillus cereus and Streptococcus parauberis (minimal effective concentration, MECs $41.6-89.7{\mu}g/ml$), gram-negative bacteria, including Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Providencia stuartii, Pseudomonas aeruginosa, and Vibrio ichthyoenteri (MECs $7.4-39.5{\mu}g/ml$), and the fungus Candida albicans (MECs $26.0-31.8{\mu}g/ml$). This antimicrobial activity was stable under heat and salt conditions. Furthermore, the peptides did not exhibit significant hemolytic activity or cytotoxic effects. These results suggest that mytilin B could be applied as alternative antibiotic agent, and they add to the understanding of the innate immunity of hard-shelled mussels.