• Journal of Korean Tunnelling and Underground Space Association
• /
• v.22 no.5
• /
• pp.529-541
• /
• 2020

Although TBM's cutterhead requires design review for fatigue failure due to wear-induced section loss as well as heavy load during excavation, it is difficult to find a case of fatigue analysis for TBM cutterhead at present. In this study, a stress-life design review was conducted on cutter heads with a diameter of 8.2 m using S-N curves as a safety life design concept. Also, we introduced the fatigue design method of construction equipment and the method of assessing fatigue damage and explained the results of the fatigue analysis on the TBM cutter head with a diameter of 8.2 m. The S-N curve has been shown to play a key role in fatigue design and can also be used to assess how much fatigue damage a structure is suffering from at this point in time. In the future, it is necessary to find out when fatigue problems occur during using the equipment and when it is good to conduct safety inspections of the equipment.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.6
• /
• pp.835-842
• /
• 2016

The phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway plays a crucial role in cancer occurrence by promoting cell proliferation and inhibiting apoptosis. In the present study, we evaluated the effect of a PI3K inhibitor, LY294002, on the chemosensitivity of gastric cancer cells to cordycepin, a predominant functional component of the fungus Cordyceps militaris, in AGS human gastric cancer cells and investigated possible underlying cellular mechanisms. Our results revealed that cordycepin inhibited viability of AGS cells in a concentration-dependent manner and induced apoptosis, as determined by apoptotic cell morphologies and fluorescence-activated cell sorting analysis associated with attenuated activation of the PI3K/Akt signaling pathway. Treatment with cordycepin in combination with a subtoxic concentration of LY294002 enhanced cordycepin-induced cytotoxicity and apoptotic potentials in AGS cells. Sensitization of LY294002 to cordycepin-induced apoptosis was accompanied by activation of caspases (caspases-3, -8, and -9) and was concomitant with poly(ADP-ribose) polymerase cleavage. Moreover, LY294002 up-regulated pro-apoptotic Bax and enhanced truncation of Bid in cordycepin-treated AGS cells, which was connected with increased loss of mitochondrial membrane potential and release of cytochrome c from mitochondria to the cytosol. Taken together, these results indicate that inhibition of the PI3K/Akt signaling pathway could augment cordycepin-induced apoptosis in human gastric cancer cells by up-regulating caspase activity through mitochondrial dysfunction.

• Resources Recycling
• /
• v.27 no.3
• /
• pp.30-38
• /
• 2018

In this study, the behaviors of Fe selective chlorination in ilmenite ore by using PVC or $CO-Cl_2$ gas mixture as reducing agents under the condition of 1173 K, for 60 minutes were investigated. The weight loss ratio was 28% when PVC was applied as the reducing agent. The condensate formed at the outlet of reaction tube was identified as $FeCl_2$ by X-ray diffraction analysis. From these results, it was observed that iron in ilmenite ore reacted with HCl gas and Fe was selectively removed in the form $FeCl_2$. However, when $CO-Cl_2$ gas mixture was used as a reducing agent, the weight reduction ratio was 54%, and the condensate formed at the outlet of reaction tube after the experiment was estimated to be $FeCl_3$. It was observed that the ilmenite ore reacted with the $CO-Cl_2$ gas mixture and was simultaneously removed in the form of $FeCl_3$ and $TiCl_4$. However, the results of X-ray diffraction of ilmenite ore after the reaction showed that Fe was almost removed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.37-43
• /
• 2019

Since 3D printed concrete can be constructed without formwork, it is easy to construct an atypical structure, and the construction time and labor cost can be reduced. However, since the construction is exposed to the outside, shrinkage cracking due to moisture loss inside and outside the concrete occurs. Therefore, in order to improve the durability of the 3D printed concrete, a shrinkage reduction plan of the 3D printed concrete is required. In this study, glycol-based and alcohol-based shrinkage reducing agents were fabricated and evaluated for their performance. The shrinkage reducing agent samples showing excellent performance were selected and applied to 3D printed concrete. As a result, the compressive strength was increased by more than 10% and the shrinkage was reduced by more than 36% when using a shrinkage reducing agent. It is expected that the production of high quality 3D printed concrete will be possible because it is possible to increase the compressive strength and reduce the amount of dry shrinkage by applying a shrinkage reducing agent for 3D printed concrete.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.12
• /
• pp.1975-1983
• /
• 2008

The neuropeptide ${\alpha}$-melanocyte-stimulating hormone (${\alpha}$-MSH) has anti-inflammatory property by down regulating the expressions of proinflammatory cytokines. Because ${\alpha}$-MSH elicits the anti-inflammatory effect in various inflammatory disease models, we examined the therapeutic effect of oral administration of recombinant Lactobacillus casei, which secretes ${\alpha}$-MSH (L. casei-${\alpha}$-MSH), on dextran sulfate sodium (DSS)-induced colitis in Balb/c mice. Thus, we constructed the ${\alpha}$-MSH-secreting Lactobacillus casei by the basic plasmid, pLUAT-ss, which was composed of a PldhUTLS promoter and ${\alpha}$-amylase signal sequence from Streptococcus bovis strain. Acute colitis was induced by oral administration of 5% DSS in drinking water for 7 days. To investigate the effect of L. casei-${\alpha}$-MSH on the colitis, L. casei or L. casei-${\alpha}$-MSH was orally administered for 7 days and their effects on body weight, mortality rate, cytokine production, and tissue myeloperoxidase (MPO) activity were observed. Administration of L. casei-${\alpha}$-MSH reduced the symptom of acute colitis as assessed by body weight loss (DSS alone: $14.45{\pm}0.2\;g$; L. casei-${\alpha}$-MSH: $18.2{\pm}0.12\;g$), colitis score (DSS alone: $3.6{\pm}0.4$; L. casei-${\alpha}$-MSH: $1.4{\pm}0.6$), MPO activity (DSS alone: $42.7{\pm}4.5\;U/g$; L. casei-${\alpha}$-MSH: $10.25{\pm}0.5\;U/g$), survival rate, and histological damage compared with the DSS alone mice. L. casei-${\alpha}$-MSH-administered entire colon showed reduced in vitro production of proinflammatory cytokines and $NF-{\kappa}B$ activation. The ${\alpha}$-MSH-secreting recombinant L. casei showed significant anti-inflammatory effects in the murine model of acute colitis and suggests a potential therapeutic role for this agent in clinical inflammatory bowel diseases.

• Analytical Science and Technology
• /
• v.27 no.6
• /
• pp.352-356
• /
• 2014

Various studies have been done to improve the properties of the steel by adding boron to the steel. Some studies have reported on the analysis of the boron in steel by AAS (atomic absorption spectrometry), ICP-OES(inductively coupled plasma-optical emission spectrometry), ICP-MS (inductively coupled plasma/mass spectrometry). The volatile loss of boron of steel in sample digestion and the separation procedure for avoiding matrix effect by high concentration of iron are difficulties for determination of boron in steel. The method to determine boron in steel by ICP-MS was developed without volatilization of boron in sample digestion step with $HNO_3-NH_4HF_2$ digestion method, and the additional separation process for avoiding matrix effect. Complete decomposition of steel with $HNO_3-NH_4HF_2$ digestion method, and boron determination by ICP-MS in the matrix of high concentration of iron were possible. Quantitative recoveries of boron in certified standard steel by new method in this study were 103 to 111%, and the relative standard deviation is less than 5%. The method detection limit was $1.17{\mu}g/g$.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.2 no.2
• /
• pp.39-51
• /
• 1994

When broiler litter was composted under the control of peak temperature of piles(uncontrolled, controled below $70^{\circ}C$ and below $60^{\circ}C$), changes of physical and chemical parameters were determined throughout the processing period. Broiler litter was composted in each of three $1.0{\times}1.0{\times}1.2m$ dimensional facilities for 8 weeks. After 5 to 6 weeks of composting, broiler litter was converted into the final compost with no ammonia odour, rice hull size of particle, and faint brown color. Central temperature of piles reached to the peak(about $69{\sim}70^{\circ}C$) within 3 to 4 days after composting and gradually decreased thereafter. The final product contained 26.5% of moisture, 9.0~9.1 of pH, and 14.0~14.3 of C/N ratio. The increase of C/N ratio with processing resulted from the considerable loss of N. The total wet weight of the final composts was an average of 38.3% of the initial weight, the dry weight of those 64.1%, and the organic matter weight of those 34.8%. Treatments of central temperature of composts did not affect changes of moisture, pH, C/N ratio, total wet weight, total dry weight, and total organic matter weight. In general, composted broiler litter was converted into the final product with little change in physical and chemical parameters after 5 to 6 weeks of processing. Nitrogen losses during the composting should be prevented for the improvement of the composting efficiency of broiler litter.

• Journal of Energy Engineering
• /
• v.19 no.4
• /
• pp.228-233
• /
• 2010

About 55% of total energy is consumed in the industrial division. The industrial heat pump application will show magnificent energy saving effect as well as higher cost efficiency because of larger energy consuming volume of each facility and longer operation hour and higher stability against seasonal temperature change. Over 90% of dryer for industrial usage has hot wind heat source and hot wind dryer is the representative type covering 68.7% while its 30 ~ 50% lower heat efficiency causes lots of energy loss by exhaust air. Re-usage of exhaust air can improve energy efficiency of dryer because 68% heat energy or 78% of hot air lose in exhaust air. Therefore, high temperature heat pump dryer can be the best alternative. Comparing to the existing dryer with 30% ~ 50% energy efficiency, newly developing high temperature heat pump dryer will enhance energy efficiency up to 60% ~ 80% efficiency. In this paper, heat pump system for high temperature was designed, constructed and tested. The results have shown that system COPh is estimated as 3.3.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.25 no.4
• /
• pp.669-673
• /
• 2011

To prevent and treat the osteoporotic fracture, more attention should be paid in old age patients. Osteoclast which has ability to bone resorption is originated from hematopoietic cell line and plays a key role osteoporotic bone loss. Rubi Fructus has been widely used in Oriental medicine. Extracts of the leaves and fruit of Rubus species have been used in various countries as natural remedies to treat diabetes, infections, colic, and burns. However, the effect of extract of Rubi Fructus (fruit of Rubus coreanus Miq.) in osteoclast differentiation remains unknown. Thus, we evaluated the effect of Rubi Fructus on receptor activator of nuclear factor-kB ligand (RANKL)-induced osteoclast differentiation. Here we found that Rubi Fructus significantly inhibited osteoclast differentiation induced by RANKL. Rubi Fructus suppressed the activation of p38 pathway and NFkB in bone marrow macrophages (BMMs) treated with RANKL. Also, Rubi Fructus significantly inhibited the mRNA expression of c-Fos, tartrate-resistant acid phosphatase (TRAP), osteoclast-associated receptor (OSCAR), nuclear factor of activated T cells (NFAT)c1 and cathepsin K in BMMs treated with RANKL. Particularly, Rubi Fructus greatly inhibited the protein expression of c-fos and NFATc1. especially in the case of NFATc1 expression, a master transcription factor of the differentiation of osteoclasts is very important step for osteoclastogenesis. Taken together, our results demonstrated that Rubi Fructus may be useful treatment option of bone-related disease such as osteoporosis and rheumatoid arthritis.

• Clinics in Shoulder and Elbow
• /
• v.2 no.2
• /
• pp.157-169
• /
• 1999

Eighty-nine shoulders in eighty-eight patients with traumatic unilateral anterior shoulder instability were evaluated for Rowe and UCLA scores, recurrence, return to activity, and range of motion by an independent examiner at an average of 39 months after either arthroscopic or open Bankart repair using suture anchors. The arthroscopic technique included a minimum of 3 anchors, and a routine incorporation of capsular plication and proximal shift. Twenty­six shoulders(86.6%) out of thirty in the open Bankart repair group had excellent or good results while fifty­four(91.5%) of the fifty-nine shoulders with arthroscopic Bankart repair had excellent or good results. The arthroscopic group revealed significantly better results in the Rowe(p=.041) and UCLA scores(p=.026). Two shoulders in each group developed redislocation. There were no significant differences in the loss of external rotation and return to prior activity between the two groups(p>.05). The residual instability occurred more frequently in the group of patients with lesser anchors. Arthroscopic suture anchor capsulorraphy has results equal to or better than the open Bankart procedure.