• Journal of the Korean Geotechnical Society
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• v.38 no.5
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• pp.5-17
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• 2022

A pile is a type of medium for constructing superstructures in weak geotechnical conditions. A pretensioned spun high-strength concrete (PHC) pile is composed of high-strength concrete with a specified strength greater than 80 MPa. Therefore, it has advantages in resistance to axial and bending moments and quality control and management since it is manufactured in a factory. However, the skin friction of a pile, which accounts for a large portion of the pile bearing capacity, is only approximated using empirical equations or standard penetration test (SPT) N-values. Particularly, there are some poor research results on the pile-soil interface under the seismic loads in Korea. Additionally, some studies do not consider geoenvironmental elements, such as groundwater pH values. This study performs sets of cyclic simple shear tests using submerged concrete specimens for 1 month to consider pH values of groundwater and clay specimens composed of kaolinite to generate a pile-soil interface. 0.2 and 0.4 MPa of normal stress conditions are considered in the case of pH values. The disturbed state concept is employed to express the dynamic behavior of the interface, and the disturbed function parameters are newly suggested. Consequently, the largest disturbance increase under basic conditions is observed, and an early approach to the failure under low normal stress conditions is presented. The disturbance function parameters are also suggested to express this disposition quantitatively.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2949-2957
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• 2020

Fatigue crack growth model has been developed for dissimilar metal weld joints of a piping component under cyclic loading, where in the crack is located at the center of the weld in the circumferential direction. The fracture parameter, Stress Intensity Factor (SIF) has been computed by using principle of superposition as K_H + K_M. K_H is evaluated by assuming that, the complete specimen is made of the material containing the notch location. In second stage, the stress field ahead of the crack tip, accounting for the strength mismatch, the applied load and geometry has been characterized to evaluate SIF (K_M). For each incremental crack depth, stress field ahead of the crack tip has been quantified by using J-integral (elastic), mismatch ratio, plastic interaction factor and stress parallel to the crack surface. The associated constants for evaluation of K_M have been computed by using the quantified stress field with respect to the distance from the crack tip. Net SIF (K_H + K_M) computed, has been used for the crack growth analysis and remaining life prediction by Paris crack growth model. To validate the model, SIF and remaining life has been predicted for a pipe made up of (i) SA312 Type 304LN austenitic stainless steel and SA508 Gr. 3 Cl. 1. Low alloy carbon steel (ii) welded SA312 Type 304LN austenitic stainless-steel pipe. From the studies, it is observed that the model could predict the remaining life of DMWJ piping components with a maximum difference of 15% compared to experimental observations.

• BMB Reports
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• v.39 no.4
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• pp.394-399
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• 2006

The transport of putrescine into a moderately salt tolerant cyanobacterium Synechocystis sp. PCC 6803 was characterized by measuring the uptake of radioactively-labeled putrescine. Putrescine transport showed saturation kinetics with an apparent $K_m$ of $92{\pm}10\;{\mu}M$ and $V_{max}$ of $0.33{\pm}0.05\;nmol/min/mg$ protein. The transport of putrescine was pH-dependent with highest activity at pH 7.0. Strong inhibition of putrescine transport was caused by spermine and spermidine whereas only slight inhibition was observed by the addition of various amino acids. These results suggest that the transport system in Synechocystis sp. PCC 6803 is highly specific for polyamines. Putrescine transport is energy-dependent as evidenced by the inhibition by various metabolic inhibitors and ionophores. Slow growth was observed in cells grown under salt stress. Addition of low concentration of putrescine could restore growth almost to the level observed in the absence of salt stress. Upshift of the external osmolality generated by either NaCl or sorbitol caused an increased putrescine transport with an optimum 2-fold increase at 20 mosmol/kg. The stimulation of putrescine transport mediated by osmotic upshift was abolished in chloramphenicol-treated cells, suggesting possible involvement of an inducible transport system.

• Journal of Plant Biotechnology
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• v.29 no.4
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• pp.277-280
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• 2002

Acid phosphatase in the radish young plant showed optimal activity at pH 5.5. The activity of acid phosphatase was maintained longer during the ABA (0.5 mM) treatment than those in control, whereas that was similar to the treatment of NaCl (0.5 mM). But during the cold (4$^{\circ}C$) treatment, the activity of acid phosphatase was decreased dramatically compared to the control, which was maintained almost on a constant level and increased gradually during 6 days. It showed that acid phosphatase was in relation to the change of biochemical reaction, which plants were coped with cold, NaCl and ABA stress.

• Journal of Life Science
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• v.12 no.2
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• pp.47-52
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• 2002

Saccharomyces cerevisiae KNU5377 (KNU5377) and S. cerevisiae ATCC24858 (ATCC24858) were exposed to $H_2SO_4$ as a stress, which was added at various concentrations to a YPD media. The growth of KNU5377 was reduced to approximately 60% in the YPD media containing 40 nm sulfuric acid when compared to the non-stressed condition. When their growth was monitored during an overnight culture, two strains, KNU5377 and ATCC24858, could not grow when exposed to over 50 mM of sulfuric acid. After a short exposure to this acid for 1 h, KNU5377 exhibited stronger resistance against $H_2SO_4$ than ATCC24858. The neutral trehalase activity of KNU5377 unchanged despite under various concentrations of $H_2SO_4$. In contrast, It at of ATCC24858 was much low at higher $H_2SO_4$concentrations. Trehalose, a non-reducing disaccharide, was maximally accumulated after a short exposure to 60 nm $H_2SO_4$ for KNU5377, but it was reduced under more severe stressful conditions. These results suggest that KNU5377 should modulate the trehalose concentrations under the severe stress condition of high sulfuric acid concentrations. The most highly induced protein in the KNU5377 exposed to sulfuric acid was found to be an approximately 23 kDa protein, which was revealed to be the 605 large subunit ribosomal protein, Ll3 by FASTA search results.

• CELLMED
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• v.8 no.3
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• pp.12.1-12.7
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• 2018

The study was designed to assess antioxidant and antidyslipidaemic effects of terpenoid-rich extract from the root of Aristolochia ringens V. Hyperglycemia-induced oxidative stress and dyslipidemia were established in rats by single intraperitoneal administration of 65 mg/kg bw streptozotocin. Based on therapeutic dose determined in previous study, streptozotocin-induced rats were orally administered with 75 and 150 mg/Kg bw of A. ringens extract for 14 days. Total protein, serum lipid profiles and biomarkers of oxidative stress in liver and kidney of the experimental rats were determined. Atherogenic and cardiovascular disease risk indices were computed. Streptozotocin-induced hyperglycaemia significantly (p < 0.05) decreased activities of superoxide dismutase, catalase and glutathione transferase as well as the amount of reduced glutathione in both tissues indicating oxidative stress induced kidney and liver injury due to glucotoxicity. In comparison to non-treated hyperglycaemic rats, activities of the antioxidant enzymes and concentration of glutathione-H were significantly (p < 0.0001) increased, whereas malondialdehyde was reduced in the tissues of rats treated with both 75 and 150 mg/Kg bw of the extract. The extract also caused significant (p < 0.001) reduction in elevated levels of total cholesterol, triglycerides and low density lipoprotein-cholesterol levels, whereas concentration of the attenuated high density lipoprotein-cholesterol was increased in serum of the treated rats. Reduced atherogenic and cardiac risk indices were projected for the A. ringens extract-treated groups. Results from this study showed that extract from A. ringens root was rich in terpenoids and may reduce risks of complications associated with hyperglycemia-induced oxidative stress and dyslipidemia.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.428-434
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• 2012

A fungal strain, capable of solubilizing insoluble phosphate under diverse temperature, pH and salt conditions was isolated from Waste Mushroom bed of Agaricus bisporus in South Korea. Based on 18S rRNA analysis, the strain was identified as Aspergillus awamori bxq33110. The strain showed maximum phosphate solubilization in AYG medium (525 ${\mu}g\;mL^{-1}$) followed by NBRIP medium (515 ${\mu}g\;mL^{-1}$). The strain solubilized $Ca_3(PO_4)_2$ to a greater extent and rock phosphate and $FePO_4$ to a certain extent. However $AlPO_4$ solubilizing ability of the strain was found to be very low. Glucose at the rate of 2% ($561{\mu}g\;mL^{-1}$) was found be the best carbon source for Aspergillus awamori bxq33110 to solubilize maximum amount of phosphate. However, no significant difference ($P{\leq}0.05$) in phosphorus solubilization was found between 1% and 2% glucose concentrations. $(NH_4)_2SO_4$ was the best nitrogen source for Aspergillus awamori bxq33110 followed by $NH_4Cl$ and $NH_4NO_3$. At pH 7, temperature $30^{\circ}C$ and 5% salt concentration (674 ${\mu}g\;mL^{-1}$) were found to be the optimal conditions for insoluble phosphate solubilization. However, strain Aspergillus awamori bxq33110 was shown to have the ability to solublize phosphate under different stress conditions at $30-40^{\circ}C$ temperature, pH 7-10 and 0-10% salt concentrations indicating it's potential to be used as bio-inoculants in different environmental conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.9
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• pp.1210-1218
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• 2000

Four experiments were conducted to evaluate the effect of temperature and humidity on biochemical indices of Arbor Acres broilers at different weeks of age. The alkaline phosphatase (AKP), acid phosphatase (ACP), lactic dehydrogenase (LD), creatine kinase (CK), plasma glucose (Glu), calcium (Ca), potassium (K), chloride (Cl), urea nitrogen (UN), uric acid (UA), plasma thyroxin (T4), triiodothyronine (T3) and insulin levels were determined in all the four experiments. In experiment 1, the plasma Glu, LD and CK levels were increased by heat exposure ($35{^{\circ}C}$ and 35, 60, or 85% RH, 2 h) and this effect was aggravated by longer exposure (24 h). No significant changes (p>0.05) were found in Ca concentration, activity of AKP and ACP. In experiment 2, temperature (10, 20, 30, $33{^{\circ}C}$) had significant effect on the levels of K, Cl, UN, UA levels and the activity of LD (p<0.01), but had no significant influence on the activity of CK (p>0.05). The UN, UK and LD levels were elevated by low temperature $(10{^{\circ}C})$ (p<0.01), Cl content was increased by high temperature ($(33{^{\circ}C})$ (p<0.01), and K level was decreased by high ($(33{^{\circ}C})$ or low $(10{^{\circ}C})$ temperature and increased by medium temperature $(30{^{\circ}C})$ (p<0.01). The humidity (35, 85% RH) only had significant effect on Cl concentration which was decreased by high humidity (p<0.01). In experiment 3, the result showed that only the LD and CK activity were significantly increased (p<0.01) by high temperature (7, 24, 28, $32{^{\circ}C}$) or high humidity (35, 85% RH). Temperature and humidity had no significant effect on K, Cl, UA, UN and Glu levels (p>0.05). In experiment 4 (24, 27, 30, $33{^{\circ}C}$; 30, 45, 60, 75, 90% RH), plasma T3 level was declined by high temperature $(33{^{\circ}C})$, and this phenomena disappeared in birds under high temperature and high humidity environment. T4 concentration in plasma was not affected by temperature (p>0.05), but was increased by high or low humidity (p<0.01). Neither temperature nor humidity had significant effect on plasma insulin concentration (p>0.05). The results of the four experiments suggested that broilers at different growth periods might have different thermal requirements and would response differently to heat exposure. The plasma biochemical indices themselves had big variation; the reaction of the indices to thermal exposure treatment differed with the age of broilers. The big variation of biochemical indices themselves might cover the response of indices to temperature and humidity treatments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1766-1772
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• 2009

In this study, we are interested in comparing the protein profiles of acid-shocked and control cells of S. mutans isolated from Korean children with caries. The results of 2D gel electrophoresis showed that twelve proteins are up-regulated when the cells were grown under 20 mM lactic acid stress in the exponential phase. Up-proteins under acid stress were estimated a major key of the survival and proliferation of S. mutans in low pH environments. These proteins are estimated generally associated with three biochemical pathways: glycolysis, alternative acid production and branched-chain amino acid biosynthesis.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.175-184
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• 1994

This was performed to investigate the antiulcer effects of Aloe vera on the stomach ulcer induced by restraint and water-immersion stress in rats. For this experiment, 60 male Sprague-Dawley strain were used. The experimental groups were divided into five: a control(CA) and 4 aloe treatment groups. Each dose of aloe was 50 mg/kg BW(AA), 100mg/kg BW(AB), 200 mg/kg BW(AC), and 400 mg/kg BW(AD). The rats were allocated to each group by 12 and observed for 4 weeks. The results are as following. 1. The stomach surface pH in each group showed no significant difference, byt the values of aloe treatment groups were higher than the value of the control group. 2. The gastric wall mucus was significantly increased in all aloe treatment groups(p<0.05) compared with the control group. Especially in AC and AD group the differences were higher(p<0.01). 3. At shear rate rate 11.25, 45.0, 90.0, 225.0 sec-1, whole blood viscosity and plasma viscosity were measured. Most of the values of aloe treatment groups were significantly low compared with those of the control group(P<0.05). 4. The ulcer index of aloe treatment groups were significantly low campared with control group(p<0.05). Especially in AC and AD group the differences were more significant(p<0.01). 5. Less severe ulcers were observed in AA and AB group than in the control group. Tissues of AC and AD group had only slight ulcers and necrosis of tissue was not observed in these groups. Especially in AD group, there was more mucus than other groups and it seemed that alove vera stimulated the epithelial regeneration. From the results of this study, it can be concluded that the oral administration of Alove vera results in protection of stomach ulcer by stimulating the secretion of gastric mucus and the circulation of blood.