• Structural Engineering and Mechanics
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• v.82 no.5
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• pp.643-650
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• 2022

In this paper a novel mathematical model and its analytical solution of global buckling behaviour of slender elastic concrete-filled double-skin tubular (CFDST) columns with finite compliance between the steel tubes and a sandwiched concrete core is derived for the first time. The model is capable of investigating the influence of various basic parameters on critical buckling loads of CFDST columns. It is shown that the elastic buckling load of circular and slender CFDST columns is independent on longitudinal contact stiffness, but, on the other hand, it can be considerably dependent on circumferential contact stiffness. The increasing of the circumferential contact stiffness increases the critical buckling load. Furthermore, it is shown that analytical results can agree well with the experimental and numerical results if the calibrated values of circumferential contact stiffness are used in the calculations. Moreover, it is shown that the contact between the steel tubes and a sandwiched concrete core of tested large-scale CFDST columns used in the comparison is relatively weak. Finally, the proposed analytical results can be used as a benchmark solution.

• Journal of the Korean Wood Science and Technology
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• v.47 no.1
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• pp.21-32
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• 2019

In order to investigate the decay process of wood treated with preservative, waterproofing agent and their compound systems, a full-cell process was applied to impregnate the sapwood of poplar (Populus cathay) at paraffin wax emulsion concentrations of 0.5% and 2.0%, Copper Azole (CA) concentrations of 0.3% and 0.5%, and their four compound systems, respectively. Leaching tests and laboratory decay resistance against the white-rot fungus Corious versicolor (L.) Murrill for treated wood were carried out according to the America Standard E11-06 and China Standard GB/T 13942.1-2009. At certain time intervals during the decay test, samples were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction technique (XRD) to investigate the time-dependent changes of chemical components and crystalline structure, thus clarifying the decay mechanisms. The results suggested that white-rot fungi degrade hemicellulose and lignin in the wood cell wall first, followed by a simultaneous degradation of polysaccharides and lignin. Besides, CA could not only slower the decomposition of both hemicellulose and lignin, but also reduce the degradation amount of hemicellulose. However, paraffin wax emulsion at high concentration had a negative effect on the impregnation of CA for the compound system treated wood.

• Parasites, Hosts and Diseases
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• v.36 no.4
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• pp.261-268
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• 1998

The present study was undertaken to investigate the role of cysteine proteinase of Trichomonas vaginalis in escaping from host defense mechanism. A cysteine proteinase of T. vaginalis was purified by affinity chromatography and gel filtration. Optimum pH for the purified proteinase activity was 6.0. The proteinase was inhibited by cysteine and serine proteinase inhibitors such as E-64, NEM, IAA, leupeptin. TPCK and TLCK, and also by $Hg^{2+}$, but not affected by serine-, metallo-, and aspartic proteinase inhibitors such as PMSF, EDTA and pepstatin A. However, it was activated by the cysteine proteinase activator, DTT. The molecular weight of a purified proteinase was 62 kDa on gel filtration and 60 kDa on SDS-PAGE. Interestingly, the purified proteinase was able to degrade serum IgA, secretory IgA, and serum IgG in time- and dose-dependent manners. In addition, the enzyme also degraded hemoglobin in a dose-dependent manner. These results suggest that the acidic cysteine proteinase of T. vaginalis may play a dual role for parasite survival in conferring escape from host humoral defense by degradation of immunoglobulins, and in supplying nutrients to parasites by degradation of hemoglobin.

• The Journal of the Acoustical Society of Korea
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• v.25 no.7
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• pp.312-318
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• 2006

The conventional lip-synch system has a two-step process, speech segmentation and recognition. However, the difficulty of speech segmentation procedure and the inaccuracy of training data set due to the segmentation lead to a significant Performance degradation in the system. To cope with that, the connected vowel recognition method using Head-Body-Tail (HBT) model is proposed. The HBT model which is appropriate for handling relatively small sized vocabulary tasks reflects co-articulation effect efficiently. Moreover the 7 vowels are merged into 3 classes having similar lip shape while the system is optimized by employing a class dependent SCHMM structure. Additionally in both end sides of each word which has large variations, 8 components Gaussian mixture model is directly used to improve the ability of representation. Though the proposed method reveals similar performance with respect to the CHMM based on the HBT structure. the number of parameters is reduced by 33.92%. This reduction makes it a computationally efficient method enabling real time operation.

• Biomedical Science Letters
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• v.22 no.2
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• pp.60-64
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• 2016

In the pathogenesis of inflammatory diseases such as allergies, S100A8 acts as an important molecule and T lymphocytes are essential cytokine-releasing cells. In this study, we investigated the effect of S100A8 on release of cytokines, specifically MCP-1, IL-6, and IL-8 in T cells, and its associated signaling mechanism. S100A8 increased secretion of MCP-1, IL-6, and IL-8 in a time- and dose-dependent manner. Elevated secretion of MCP-1, IL-6, and IL-8 due to S100A8 was inhibited by the TLR4 inhibitor TLR4i, the PI3K inhibitor LY294002, the $PKC{\delta}$ inhibitor rottlerin, the ERK inhibitor PD98059, the p38 MAPK inhibitor SB202190, the JNK inhibitor SP600125, and the NF-${\kappa}B$ inhibitor BAY-11-7085. S100A8 induced phosphorylation of ERK, p38 MAPK, and JNK in a time-dependent manner, and activation was suppressed by TLR4i, LY294002, and rottlerin. S100A8 induced NF-${\kappa}B$ activation by $I{\kappa}-B{\alpha}$ degradation, and NF-${\kappa}B$ activity was suppressed by PD98059, SB202190, and SP600125. These results indicate that S100A8 induces cytokine release via TLR4. Study of PI3K, $PKC{\delta}$, MAPKs, and NF-${\kappa}B$ will contribute to elucidation of the S100A8-invovled mechanism.

• Journal of the Korean Geotechnical Society
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• v.30 no.4
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• pp.21-34
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• 2014

This paper studies the time-dependent behaviors of tunnel and surrounding ground due to tunnel deterioration. In the first part, the literature on deterioration characteristics of tunnels was reviewed. In the second part, a numerical analysis was performed to investigate the behavior of concrete lining on the typical section of Korean high-speed rail tunnel (weathered rock) after determination of input variables related to deterioration impact. The result shows that the settlement at the crown of tunnel and surface ground increased up to 7.0% and 30.2% of the total settlements during construction stage, respectively, and the internal convergence reduction of 9.0 mm for concrete linings was generated within 30 years after completion of tunnel construction. Also the loosening height increased up to 2.55 times of tunnel height within 50 years, which is higher than that of Terzaghi's recommendation on ultimate state. Due to this process of extending zones, it is found that additional loads were applied to concrete lining with the axial stress about 3.20~3.66 MPa, which accelerates tunnel deterioration. Finally the quantitative design approach to evaluate time-dependent behavior of lining and surrounding ground due to tunnel deterioration was proposed.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.571-582
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• 2022

Cacao, a major ingredient for making chocolate, has been shown to have potent antioxidant effects. The consumption of raw cacao has beneficial effects on health. This study determined the fermentation properties of yoghurt that was manufactured with cacao nibs (Theobroma cacao L.). The pH of the yogurt containing the cacao nibs was lower than that of the control, and this reduction was both concentration and fermentation time-dependent. Furthermore, the number of lactic acid bacteria in the yogurt made with cacao and its viscosity increased in a cacao nibs dependent manner. In particular, the yoghurt with 5% cacao nibs added had the highest number of lactic acid bacteria at 48 hours at the end point of the fermentation. Whey protein degradation in yogurt containing cacao nibs increased with the fermentation time, and the organic acid production, especially lactic acid, in the yogurt containing cacao nibs increased significantly after 16 hours of fermentation. In addition, the total polyphenol content of the yogurt containing cacao nibs increased, which was proportional to the amount added. Sensory evaluations of the yogurts indicated that overall taste was less desirable as cacao nib loadings increased from 1 to 5% compared with controls. This result is due to the excessive acidity, which was strongly perceived in the absence of added sugar. The development of yogurts with cacao nibs is expected to contribute much to the appeal of fermented milk.

• Speech Sciences
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• v.11 no.2
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• pp.181-192
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• 2004

This paper presents an efficient speech interactive agent rendering smooth car navigation and Telematics services, by employing embedded automatic speech recognition (ASR), distributed speech recognition (DSR) and text-to-speech (ITS) modules, all while enabling safe driving. A speech interactive agent is essentially a conversational tool providing command and control functions to drivers such' as enabling navigation task, audio/video manipulation, and E-commerce services through natural voice/response interactions between user and interface. While the benefits of automatic speech recognition and speech synthesizer have become well known, involved hardware resources are often limited and internal communication protocols are complex to achieve real time responses. As a result, performance degradation always exists in the embedded H/W system. To implement the speech interactive agent to accommodate the demands of user commands in real time, we propose to optimize the hardware dependent architectural codes for speed-up. In particular, we propose to provide a composite solution through memory reconfiguration and efficient arithmetic operation conversion, as well as invoking an effective out-of-vocabulary rejection algorithm, all made suitable for system operation under limited resources.

• Archives of Pharmacal Research
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• v.28 no.11
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• pp.1257-1262
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• 2005

MMP-9 is a metalloproteinase capable of basement membrane degradation in vivo. Expression of MMP-9 can be found in normal conditions such as trophoblasts, osteoclasts, and leukocytes and their precursors. They also occur as well as in pathological conditions, such as the invasive growth of primary tumors, metastasis, angiogenesis, rheumatoid arthritis, and periodontal diseases. MMP-9 upregulation can be highly induced by a wide range of agents. These agents include growth factors, cytokines, cell-cell, and cell-ECM adhesion molecules, and agents altering cell shape. Here, we observed that TNF-$\alpha$ stimulated human monocytic cell line, HL-60 produced MMP-9 in a dose and time dependent manner. Real time PCR results indicated transcriptional upregulation of MMP-9 as early as 3 h post TNF-$\alpha$ stimulation. To investigate the signaling pathway underlined in TNF-$\alpha$ induced MMP-9 expression, three MAP kinase inhibitors were added to cells 1 h prior to TNF-$\alpha$ treatment. The ERK inhibitor completely abolished MMP-9 expression by TNF-$\alpha$. But neither p38 MAP kinase nor JNK inhibitor had an effect on TNF-$\alpha$ induced MMP-9 expression, suggesting that ERK activation is required for the MMP-9 induction by TNF-$\alpha$. Taken together, we found that TNF-$\alpha$ stimulation facilitates ERK activation, which results in the transcriptional upregulation of MMP-9 gene and subsequent MMP-9 production and secretion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.169-172
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• 2004

The effect of the process parameters on the stable lifetime in rapid thermal firing(RTF) was investigated in order to optimize the process for the Cz-silicon. The process temperature was varied between $700^{\circ}C\;and\;950^{\circ}C$ while the process time was chosen 1 s and 10 s. At below $850^{\circ}C$ the stable lifetime for 10 s is higher than that for 1 s and increases with increasing by the process temperature. However, at over $850^{\circ}C$ the improved stable lifetime is not dependent on the process time and temperature. On the other hand, two high temperature processes in solar cell fabrics are combined with the optimized process and the non-optimized process. The last process determines the stable lifetime. Also, the degraded stable lifetime could be increased by processing in optimized process. The decreased lifetime can increase using the optimized oxidation process, which is a final process in solar cells. Finally, the optimized and non-optimized processes are applied solar cells.