• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.693-698
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• 1992

The resistant effect of several heavy metal ions to Serratia marcescens strain P was studied by the method of minimal inhibitory concentration(MIC), and testing for their metal biosorption. S. marcescens strain P showed a good survival in the presence of high concentrations of some metal ions, namely cadmium, lead, iron, magnesium, and manganese. Copper had the most inhibitory effect among tested. The MIC value was ranged from 0.79 to 1.58 mM. Cells of S. marcescens strain P exhibit an abnormally long lag phase when incubated in high concentrations of zinc and cadmium. Pigment production was reduced by zinc and cadmium, but enhanced by lead and iron. S. marcescens strain P was resistant to ampicillin, tetracycline, cefamandole and chloramphenicol with minimal inhibitory concentration of 128 $\mu$g/ml, 32 $\mu$g/ml, 256 $\mu$g/ml, and 8 $\mu$g/ml, respectively. The kinetics study of biosorptive uptake by S. marcescens strain P revealed that 16.59% of cadmium and 35.38% of lead were eliminated from the media.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.967-974
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• 2007

The present work is aimed to evaluate the protective effect of glutathione-enriched Saccharomyces cerevisiae FF-8 strain on carbon tetrachloride ($CCl_4$)-induced hepatotoxicity and oxidative stress in rats. The activities of liver markers (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase), lipid peroxidative index (thiobarbituric acid-reactive substances), and the antioxidant status (reduced glutathione) were used to monitor those protective roles of FF-8 strain. The liver marker enzymes in plasma and the lipid peroxidation in the liver were increased when $CCl_4$ was treated but these were significantly decreased by FF-8 strain treatment. The hepatic concentration of glutathione in the current glutathione-enriched FF-8 strain fed animal was approximately twice as high as the normal, but this was slightly increased in response to $CCl_4$ plus glutathione-enriched FF-8 strain. The increased liver triglyceride concentration due to the $CCl_4$ treatment was significantly decreased by FF-8 strain and the reduced level reached to that of normal group. Administration of FF-8 strain in normal rat did not show any signs of harmful effects. Therefore, the current findings suggest that FF-8 strain could be an effective antioxidant with no or negligible side-effects and it might be useful for the purpose of protection treatment of hepatotoxicity and oxidative stress in $CCl_4$-treatment in rat.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.76-85
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• 2017

In this study, to evaluate the mechanical properties of fiber-reinforced cement composites by strain rate, hydraulic rapid loading test system was developed. And compressive and tensile strength of the hooked steel fiber and polyamide fiber reinforced cement composite were evaluated. As a result, the compressive strength, strain capacity and elastic modulus were increased with increasing strain rate. The effect of compressive strength by type and volume fraction of fibers was not significant. The dynamic increase factor(DIF) of the compressive strength was higher than that of the CEB-FIP model code 2010 and showed a trend similar to that of ACI-349. The tensile strength and strain capacity were increased with increasing strain rate. The hooked steel fibers were drawn from the matrix. The tensile strength and strain capacity of hooked steel fiber reinforced cement composites were increased as the strain rate increased. The tensile strength and deformation capacity of the fiber reinforced cement composites were increased. And, hooked steel fibers were drawn from the matrix. On the other hand, because the bonding properties of polyamide fiber and matrix is large, polyamide fiber was cut-off with out pullout from matrix. The strain rate effect on the tensile properties of polyamide fiber reinforced cement composites was found to be strongly affected by the tensile strength of the fibers.

• Korean Journal of Poultry Science
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• v.41 no.3
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• pp.205-215
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• 2014

The aim of this study was to determine the effects of stocking density and strain on the performance and physiological adaptive responses including the plasma corticosterone content and the level of mRNA expression of pro-inflammatory cytokines and antioxidant enzymes in broiler chicks. A total of 300 birds of two strains (150 Ross strain vs. 150 Cobb strain) aged 3-d old were allotted into two stocking densities (standard stocking density,$0.046m^2/bird$ vs. high stocking density, $0.023m^2/bird$) in battery cages by $2{\times}2$ factorial designs with ten replicates until 35 d of age. There was no significant strain effect on body weight, feed intakes and feed to gain ratio and the relative organ weights. However body weight, feed intakes and relative organ weight were found to be significantly (P<0.05) affected by the effect of stocking density. Plasma corticosterone level was not affected by both stocking density and strain effects. Hepatic mRNA expression of pro-inflammatory cytokines including interleukin-$1{\beta}$ (IL-$1{\beta}$), IL-6, IL-18 and interferon-gamma (IFN-${\gamma}$) was not significantly changed by the effects of strain and stocking density. However, the mRNA expression of glutathione peroxidase (GPX) was affected by strain, showing that Ross strain decreased (P<0.05) the GPX expression. With respect to the effect of stocking density, there was a significant (P<0.05) increase in superoxide dismutase (SOD) and catalase (CAT) and GPX mRNA expression in the liver from high stocking density group. Splenic pro-inflammatory cytokine expression was not also affected by stocking density and strain, except that IL-18 mRNA significantly (P<0.05) decreased in Cobb strain under high stocking density. The mRNA expression of SOD and CAT was significantly (P<0.05) affected by the effects of stocking density and strain. In conclusion, growth performance was not affected by strain but stocking density. Although mRNA expression of major pro-inflammatory cytokines was not changed by stocking density and strain, antioxidant enzyme was significantly affected by stocking density, strain or even organ in birds under summer conditions. More detailed studies still needed to be explored to elucidate the effects of environmental conditions and genetic background on physiological responses in birds.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.202-207
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• 2004

An elastic-plastic finite element analysis of fatigue crack closure is performed for plane strain conditions. The stabilization behavior of crack opening level and the effect of mesh size on the crack opening stress are investigated. In order to obtain a stabilized crack opening level for plane strain conditions, the crack must be advanced through approximately four times the initial monotonic plastic zone. The crack opening load tends to increase with the decrease of mesh size. The mesh size nearly equal to the theoretical plane strain cyclic plastic zone size may provide reasonable numerical results comparable with experimental crack opening data. The crack opening behavior is influenced by the crack growth increment and discontinuous opening behavior is observed. A procedure to predict the most appropriate mesh size for different stress ratio is suggested. Crack opening loads predicted by the FE analysis based on the procedure suggested resulted in good agreement with experimental ones within the error of 5 %. Effect of the distance behind the crack tip on the crack opening load determined by the ASTM compliance offset method based on the load-displacement relation and by the rotational offset method based on the load-differential displacement relation is investigated. Optimal gage location and method to determine the crack opening load is suggested.

• Composites Research
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• v.14 no.6
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• pp.32-37
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• 2001

It is known that recoating or protection with glass-tube can prevent FBG sensor from being affected by birefringence. However, the effect on the strain transfer of such treatment has not been verified yet. Three types (uncoated, recoated and glass-tube protection) of FBG sensors are fabricated to verify the effect on the strain transfer of each treatment. The strain from each sensor embedded into a graphite/epoxy composite specimen was compared with that of ESG attached on the surface through the tensile test. And the signal characteristics of each sensor were also compared using the tensile test of a tapered aluminum specimen which was under the state of strain gradient.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.445-453
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• 2007

The effect of an electrochemically generated oxidation-reduction potential and electric pulse on ethanol production and growth of Saccharomyces cerevisiae ATCC 26603 was experimented and compared with effects of electron mediators (neutral red, benzyl viologen, and thionine), chemical oxidants (hydrogen peroxide and hypochlorite), chemical reductants (sulfite and nitrite), oxygen, and hydrogen. The oxidation (anodic) and reduction (cathodic) potential and electric pulse activated ethanol production and growth, and changed the total soluble protein pattern of the test strain. Neutral red electrochemically reduced activated ethanol production and growth of the test strain, but benzyl viologen and thionine did not. Nitrite inhibited ethanol production but did not influence growth of the test strain. Hydrogen peroxide, hypochlorite, and sulfite did not influence ethanol production and growth of the test strain. Hydrogen and oxygen also did not influence the growth and ethanol production. It shows that the test strain may perceive electrochemically generated oxidation-reduction potential and electric pulse as an environmental factor.

• Structural Engineering and Mechanics
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• v.47 no.2
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• pp.185-207
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• 2013

In flexural strength design of normal-strength concrete (NSC) beams, it is commonly accepted that the distribution of concrete stress within the compression zone can be reasonably represented by an equivalent rectangular stress block. The stress block it governed by two parameters, which are normally denoted by ${\alpha}$ and ${\beta}$ to stipulate the width and depth of the stress block. Currently in most of the reinforced concrete (RC) design codes, ${\alpha}$ and ${\beta}$ are usually taken as 0.85 and 0.80 respectively for NSC. Nonetheless, in an experimental study conducted earlier by the authors on NSC columns, it was found that ${\alpha}$ increases significantly with strain gradient, which means that larger concrete stress can be developed in flexure. Consequently, less tension steel will be required for a given design flexural strength, which improves the ductility performance. In this study, the authors' previously proposed strain-gradient-dependent concrete stress block will be adopted to produce a series of design charts showing the maximum design limits of flexural strength and ductility of singly-and doubly-NSC beams. Through the design charts, it can be verified that the consideration of strain gradient effect can improve significantly the flexural strength and ductility design limits of NSC beams.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.10
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• pp.896-901
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• 2002

The polarization and strain behavior of multilayer ceramic actuators fabricated by tape casting using a PNN-PZT ceramics were investigated in association with electrode size and internal layer number. Spontaneous polarization and strain decreased with increasing electrode size. In addition, the increase of internal layer number brought reduced spontaneous polarization and increased the field-induced strain. Because the actuators structure is designed to stack ceramic layer and electrode layer alternatively, the ceramic-electrode interfaces may act as a resistance to motion of domain wall. To analyze the effect of ceramic-electrode interface, the diffraction intensity ratio of (002) to (200) planes was calculated from X-ray diffraction patterns of samples subjected to a voltage of 200 V. The diffraction intensity ratio of (002) to (200) planes was decreased with increasing electrode size and internal layer number. The diffraction intensity ratio and straining behavior analyses indicate that the Polarization and strain were affected by the amount of 90°domain decreasing with increasing electrode size and internal layer number. Consequently, the change of polarization and displacement with respect to electrode size and layer number is likely to be caused by readiness of the domain wall movement around the interface.

• Journal of Power System Engineering
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• v.21 no.2
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• pp.20-26
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• 2017

This study was carried out to investigate the effect of precipitate on the high temperature deformation stability of incoloy 825 alloy. $Cr_{23}C_6$ carbide was precipitated under $950^{\circ}C$, but was not detected over $1,000^{\circ}C$. Most of the precipitation consist of $Cr_{23}C_6$ carbide. Strain-rate sensitivity was the highest in 0.01/s and the lowest in 10/s. Strain-rate sensitivity was decreased sharply below $950^{\circ}C$. In the temperature between $850^{\circ}C{\sim}1,150^{\circ}C$, plastic instable area did not exist. It showed the lowest Ziegler Parameter value of 0.06 Ziegler Parameter was the lowest as 0.06 at $850^{\circ}C$ with 10s-1 of strain. The highest Ziegler Parameter value(0.43) was found in plastic deformation at $1,050^{\circ}C$ with 0.01s-1 of strain. It tends to have an higher resistance to the high temperature deformation under $950^{\circ}C$, due to the precipitation.