• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.2
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• pp.68-77
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• 2019

C/SiC composites were developed by a liquid silicon infiltration(LSI) method for use as heat-resistant parts of solid and liquid rocket propulsion engines. The heat resistance characteristics according to the composition ratio (carbon / silicon / silicon carbide) were evaluated by specimen test through arc plasma, supersonic torch test. An ablation equation for oxidation reactions was presented. Through the combustion test it was verified that various parts such as nozzle insert, exit cone and combustion chamber heat resistant parts for rocket propulsion can be manufactured and proved high ablation performance and thermal structure performance.

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1481-1489
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• 2021

Early and accurate detection of pathogens is important to improve clinical outcomes of bloodstream infections (BSI), especially in the case of drug-resistant pathogens. In this study, we aimed to develop a culture-independent digital PCR (dPCR) system for multiplex detection of major sepsis-causing gram-negative pathogens and antimicrobial resistance genes using plasma DNA from BSI patients. Our duplex dPCR system successfully detected nine targets (five bacteria-specific targets and four antimicrobial resistance genes) through five reactions within 3 hours. The minimum detection limit was 50 ag of bacterial DNA, suggesting that 1 CFU/ml of bacteria in the blood can be detected. To validate the clinical applicability, cell-free DNA samples from febrile patients were tested with our system and confirmed high consistency with conventional blood culture. This system can support early identification of some drug-resistant gram-negative pathogens, which can help improving treatment outcomes of BSI.

• Archives of Pharmacal Research
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• v.19 no.1
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• pp.46-51
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• 1996

The in vitro activity of LB 10517, a new catechol-substituted cephalosporin, was compared with those of E-1077, cefpirome and ceftazidime 1034 clinical isolates collected in Japan. LB10517 showed a broad-spectrum antibacterial activity against a wide range of grampositive and gram-negative bacteria including non-glucose fermenting rods, Pseudomonas aeruginosa. Against the methicillin-susceptible strains of Staphylococcus aureus (MSSA) and Strptoccus pyogenes, the $MIC_{90}$ values of LB10517 which required to inhibit 90% of the strains wre $3.13\mug/ml\; and\; 0.1\mug/ml$, respectively. It was as active as E-1077 but more active than cefpirome and ceftazidime. Methicillin-resistant strains of S.aureus (MRSA) and Enterococcus spp. were highly resistant to all the test compunds. LB10517 was highly active against most members of the family Enterobacteriaceae, 90% of which were inhibited at a concentration of less than $0.78\mug/ml$, except for Enterobacter cloacae ($1.56\mug/ml$) and Serratia marcescens ($3.13\mug/ml$)Its activity was comparable to those of E-1077 and cefpirome but it was greater than that of ceftazidime. Against Pseudomonas aeruginosa, LB10517 showed the most potent antibacterial activity among the compounds tested. Ninety percent of P. aeruginosa isolates were susceptible at the concentration of $0.39\mug/ml$. Its activity was 32-to 128 fold higher than those of E-1077, cefpirome and ceftazidime. Against imipenem- or ofloxacin-resistant P. aeruginosa, LB10517 with $MIC_{90}\; of\; 6.25 \\mug/ml\; and\; 3.13\mug/ml$, respectively, showed 16-fold more potent activity than the other test compounds. LB10517 showed a relatively high plasma level and long plasma elimination half-life in rats $(t_{1/2}(\beta,\; 52 min)\; and\; dogs\; (t_{1/2}(\beta),\; 103 min)$.

• Nutrition Research and Practice
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• v.6 no.1
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• pp.16-20
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• 2012

The effects of retrograded rice on body weight gain, gut functions, and hypolipidemic actions in rats were examined. When the retrograded rice was produced by repetitive heating and cooling cycles, it contained significantly higher amounts of resistant starch ($13.9{\pm}0.98%$) than is found in common rice ($9.1{\pm}1.02%$) (P < 0.05). Sprague-Dawley rats were fed either common rice powder or retrograded rice powder, and mean body weight gain was significantly lower in the retrograded rice group (P < 0.05). The liver weight of the retrograded rice group ($14.5{\pm}0.5\;g$) was significantly lower than that of the common rice group ($17.1{\pm}0.3\;g$, P < 0.05). However, the weights of other organs, such as the kidney, spleen, thymus, and epididymal fat pad were not significantly affected by rice feeding. Intestinal transit time tended to be lower in rats fed retrograded rice when compared to rats fed the common rice, but the difference was not significant. The retrograded rice diet significantly increased stool output when compared to that in the common rice powder diet (P < 0.05), whereas fecal moisture content (%) was significantly higher in the retrograded rice group ($23.3{\pm}1.2$) than that in the common rice group ($19.1{\pm}1.2$) (P < 0.05). The retrograded rice group had significantly lower plasma cholesterol (P < 0.05), liver cholesterol (P < 0.05), and triacylglycerol contents in adipose tissue (P < 0.05) when compared to those in the common rice group. In conclusion, retrograded rice had higher resistant starch levels compared with those of common rice powder, and it lowered body weight gain and improved lipid profiles and gut function in rats.

• BMB Reports
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• v.44 no.1
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• pp.34-39
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• 2011

Resistance to PAI-1 is a factor which confers clinical benefits in thrombolytic therapy. The only US FDA approved PAI-1 resistant drug is Tenecteplase$^{(R)}$. Deletion variants of t-PA have the advantage of fewer disulfide bonds in addition to higher plasma half lives. A new variant was developed by deletion of the first three domains in t-PA in addition to substitution of KHRR 128-131 amino acids with AAAA in truncated t-PA. The specific activity of this new variant, $570\;IU/{\mu}g$, was found to be similar to those found in full length t-PA (Alteplase$^{(R)}$), $580\;IU/{\mu}g$. A 65% and 85% residual activity after inhibition by rPAI-1 was observed for full length and truncated-mutant form, respectively. This new variant as the first PAI-1 resistant truncated t-PA may offer more advantages in clinical conditions in which high PAI-1 levels makes the thrombolytic system prone to re-occlusion.

• The Plant Pathology Journal
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• v.28 no.4
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• pp.401-408
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• 2012

Initial subcellular responses in susceptible (PI 274420) and resistant (cv. Hartwig) soybeans infected with the soybean cyst nematode (SCN) were examined 2 and 4 days after inoculation (DAI). Subcellular features common to both soybeans at 2 DAI included hypertrophied initial syncytial cells (ISCs) and syncytium-component cells (SCs) with a dense cytoplasm containing proliferated rough and smooth endoplasmic reticulum (RER and SER), a hypertrophied nucleolus, and reduced vacuoles, suggesting that the nematode-infected cells were dedifferentiated. In the resistant soybean, a striking initial subcellular difference from the susceptible soybean was the dilation of the RER, indicating ER dysfunction and leading to cell death. This disturbed nematode feeding, as evidenced by disrupted feeding tubes. In PI 274420, the ISC cytoplasm was depleted, with the exception of ER membranes, at 4 DAI, while the SC cytoplasm was dense with proliferation of starch-containing plastids around multiple nuclei that might be derived from the congregation of nuclei in the neighboring SCs and in part by nuclear division without cytokinesis. In cv. Hartwig, syncytia were necrotized with secondary cell wall thickening outside the plasma membrane and an extremely dense cytoplasm containing a nucleus with an electron-lucent nucleolus, accompanied by the proliferation of closely stacked parallel RER and ribosomes. These results suggest that syncytia develop continuously in PI 274420 to produce and store nutritional substances in SCs, providing for the nematode through ISC until maturation, but in cv. Hartwig, syncytia degenerate early due to excessive metabolism, blocking nematode feeding and cytoplasmic connections with adjacent intact cells.

• Journal of Life Science
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• v.32 no.2
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• pp.148-154
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• 2022

Focal adhesion kinase (FAK) is known to regulate cell adhesion, migration, and mechanotransduction in focal adhesions (FAs). However, studies on how FAK activity is regulated in the plasma membrane microdomains according to the composition of extracellular matrix (ECM) proteins are still lacking. A genetically encoded fluorescence resonance energy transfer (FRET)-based biosensor can provide useful information on the activity of intracellular signals with high spatiotemporal resolution. In this study, we analyzed the FAK activities in lipid raft (detergent-resistant membrane) and non-lipid raft (non-detergent-resistant membrane) microdomains using FRET-based membrane targeting FAK biosensors (FAK-Lyn and FAK-KRas biosensors) under four different ECM protein compositions: glass, type 1 collagen, fibronectin, and laminin. Interestingly, FAK activity in response to laminin in a lipid raft microdomain was lower than that in other ECM conditions. Cells subjected to fibronectin showed higher FAK activity in a lipid raft microdomain than that in a non-lipid raft microdomain. Therefore, this study demonstrates that the FAK activity can be distinctively regulated according to the ECM type and the environment of the plasma membrane microdomains.

• The Korean Journal of Ceramics
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• v.3 no.2
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• pp.88-91
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• 1997

The diamondlike (DLC) films were deposited by RF plasma CVD system which had cathode consisting of mesh sheet, for the purpose of a protection from wear of OPC surface of the electrophotographic photosensitive body. Material charateristics and tribological properties of the films were also investigated and finally copying performance was evaluated with DLC deposited OPC samples. The surface resistance of the DLC film unaffected by the surface potential of the OPC was about $10^{11}{\Omega}$ and its hardness was about 1200 kg/$\textrm{mm}^2$. In this case the film showed typical material strcture of dimondlike hydrocarbon. The friction coefficient of the film was lowered to 0.2~0.3 at the optimum condition in this investigation and their wear resistant was inproved by DLC-deposition on the OPC surface. DLC-deposited OPC samples with a good copying performance without image flow and draft could be obtained at some depositing conditions.

• Journal of Nutrition and Health
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• v.28 no.9
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• pp.846-854
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• 1995

Taurine concentrations in blood and various tissues were measured in cats fed normal trurine diet(0.15% taurine) and trurine-free diet(0% taurine) for 5 weeks and 12 weeks, respectively. Cumulative body weight gain in young cats fed normal taurine diet and taurine-free diet for the initial 5 weeks were 463$\pm$43g and 383$\pm$53g respectively. Taurine concentration was one to two orders magnitude higher in most tissues than in plasma, among which the liver taurine-free diet for 12 weeks resulted in 98% reduction in plasma taurine concentration, 93% reduction in whole blood tarurine concentration, and 40~90% reduction in tissue taurine concentrations compared to the values for normal taurine diet group. Among the tissues tested, taurine depletion was most profound in heart and kidney, while liver and intestine were relatively resistant to taurine depletion. Whole blood taruined concentration appeared to be a better index for the body taurine status of cats as in more closely reflects the rate of taurine depletion in tissues. Taurine depletion in cats significantly increased the concentrations of essential and non-essential free amino acids in liver, while free amino acid concentrations in other tissues were not affected by taurine depletion.

• Advances in materials Research
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• v.8 no.4
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• pp.275-293
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• 2019

The engine parts material used in gas turbines (GTs) should be resistant to high-temperature variations. Thermal barrier coatings (TBCs) for gas turbine blades are found to have a significant effect on prolonging the life cycle of turbine blades by providing additional heat resistance. This work is to study the performance of TBCs on the high-temperature environment of the turbine blades. It is understood that this coating will increase the lifecycles of blade parts and decrease maintainence and repair costs. Experiments were performed on the gas turbine blade to see the effect of TBCs in different combinations of materials through the air plasma method. Three-layered coatings using materials INCONEL 718 as base coating, NiCoCrAIY as middle coating, and La₂Ce₂O₇ as the top coating was applied. Finite element analysis was performed using a two-dimensional method to optimize the suitable formulation of coatings on the blade. Temperature distributions for different combinations of coatings layers with different materials and thickness were studied. Additionally, three-dimensional thermal stress analysis was performed on the blade with a commercial code. Results on the effect of TBCs shows a significant improvement in thermal resistance compared to the uncoated gas turbine blade.