• Carbon letters
• /
• v.25
• /
• pp.25-32
• /
• 2018

In this study, a thermal-gradient chemical vapor infiltration (TG-CVI) process was numerically studied in order to enhance the deposition uniformity within the preform. The computational fluid dynamics technique was used to solve the governing equations for heat transfer and gas flow during the TG-CVI process for two- and three-dimensional (2-D and 3-D) models. The temperature profiles in the 2-D and 3-D models showed good agreement with each other and with the experimental results. The densification process was investigated in a 2-D axisymmetric model. Computation results showed the distribution of the SiC deposition rate within the preform. The results also showed that using two-zone heater gave better deposition uniformity.

• YAKHAK HOEJI
• /
• v.32 no.6
• /
• pp.386-393
• /
• 1988

Chemical transformation of D-glucose to 2-keto-L-gulonic acid and L-ascorbic acid has been examined. D-Sorbitol obtained from D-glucose was microbiologically oxidized to L-sorbose by G. suboxydans in 90% yield. On treatment of L-sorbose with acetone in the presence of sulfuric acid, its diacetonide is obtained in 95% yield. This diacetonide is oxidized to the corresponding acid with nickel chloride-hypochlorite, and the acid is directly transformed to L-ascorbic acid. The over all yield of Vitamin C from D-glucose achieved is 54%.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.5
• /
• pp.825-830
• /
• 2016

The purpose of this study optimizes the conditions of PLA printing material for 3D printer. Deltabot type 3D printer is used. The ranges of printing temperature, printing speed, and infill density are $195{\sim}215^{\circ}C$, 10~70mm/sec, and 10~100% respectively. From the results of printing temperature, printing quality is almost same every printing temperature. From the results of printing speed and infill density, printing quality is excellent under 40mm/sec, and over 50% respectively. Surface roughness is $2.28{\mu}mRa$ at $205^{\circ}C$, 10mm/sec, 100%, and is $5.93{\mu}mRa$ at $205^{\circ}C$, 70mm/sec. Surface roughness is directly proportional to the printing speed, and is inversely proportional to the infill density. Objects fabricated PLA printing material adhere bed at room temperature.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.10
• /
• pp.929-933
• /
• 1995

The electronic band structure and electrical properties of KMo4O6 containing chains of condensed molybdenum octahedra are analyzed by means of the extended Hu&ckel tight-binding method. KMo4O6 has partially filled bands of 1D as well as 3D character. They also exhibit the anisotropic band dispersions with bandwidths much larger along the c* axis than along the directions perpendicular to it. Thus, conduction electrons are essentially delocalized along the c* direction (i.e., the chain of condensed molybdenum octahedra) in the solid. The 1D band of two partially filled d-block bands leads to Fermi surface nesting with the wave vector q=0.3c*. The CDW instability due to this nesting is expected to cause the phase transition associated with the resistivity anomaly at low temperature. The characteristics of metallic behavior in the crystallographic ab plane are explained on the basis of the unnested 2D Fermi surfaces.

• Microbiology and Biotechnology Letters
• /
• v.50 no.4
• /
• pp.477-487
• /
• 2022

Probiotics provide a symbiotic relationship and beneficial effects by balancing the human intestinal microbiota. The relationships between microbiota changes and various diseases may predict health abnormalities and diseases. Treatment with vitamins and probiotics is one therapeutic approach. To evaluate the effect of probiotics on vitamin absorption, we chose Lactobacillus rhamnosus CBT-LR5 treatment, which has resistance to vitamin C-inducible toxicity, with vitamins in high-fat diet (HFD)-induced obesity models. CBT-LR5 affected the absorption of micronutrients, such as ionic minerals and water-soluble vitamins. An increase in vitamin C absorption by CBT-LR5 enhanced the antioxidant response in HFD-induced obesity models. Increased vitamin B absorption by CBT-LR5 regulated lipid metabolism in HFD-induced obesity models. These favorable effects of CBT-LR5 on the absorption of vitamins should be investigated as candidate therapeutic target treatments for metabolic diseases.

• Structural Monitoring and Maintenance
• /
• v.10 no.4
• /
• pp.339-360
• /
• 2023

In this paper, to assess the performance of a multi-span simply supported RC bridge, the dynamic characteristics of the bridge were measured and determined by structural health monitoring and resilient assessment via operational modal analysis as well as FE modeling. Supporting finite element (FE) models were created and analyzed according to the design drawings. This study used 2D plane monitoring of locations of hole in the infill wall and used 3D health monitoring and resilient assessment. From the results of 3Dsymmetric frame, if the frame is unsymmetrical, the used model can lead to the reduction in the internal forces. The recommendations from this study is from some discrepancies observed between 2D and 3D models, if possible 3D model should be used in analyzing the real frames.

• Journal of Life Science
• /
• v.30 no.8
• /
• pp.672-679
• /
• 2020

Distal myopathy is a clinically and genetically heterogeneous group of degenerative diseases of the distal muscle. Glycogen storage disease type IXD (GSD9D) is a metabolic distal myopathy characterized by muscle deficiency of phosphorylase kinase, a key regulatory enzyme in glycogen metabolism. Affected individuals may develop muscle weakness, degeneration, and cramps, as well as abnormal muscle pain and stiffness after exercise. It has been reported that mutations in the PHKA1 gene which encodes the alpha subunit of muscle phosphorylase kinase cause GSD9D. In this study, we examined a Korean GSD9D family with a c.3314T>C (p.I1105T) mutation in the PHKA1 gene. This mutation has not been previously reported in any mutation database nor was it found in 500 healthy controls. The mutation region is well conserved in various other species, and in silico analysis predicts that it is likely to be pathogenic. To date, only seven mutations in the PHKA1 gene have been documented, and this is the first report of Korean GSD9D patients. This study also describes and compares the clinical symptoms and pathological conditions of previously reported cases and these Korean patients. We believe that our findings will be useful for the molecular diagnosis of GSD9D.

• Food Science and Preservation
• /
• v.16 no.1
• /
• pp.128-133
• /
• 2009

We performed an experiment of keeping the extension of raw and semi-dried flounder (Pleuronectes herzensteini). The effect of with (WG) or without gill (OG), drying degree (20% drying: 20D, 40% drying: 40D) and storage temperature($5^{\circ}C$) and 0.1% chitosan-ascorbate (CA) treatment of vacuum packaging flounder on the growth of contaminated microorganism during storage for 10 days were investigated. Total aerobacter (TA) in the OG-treated raw flounder was $0.29{\sim}0.44$ log cycle lower than that of WG-treated flounder. Also, the number of Staphylococcus aureus (SA) and E. coli (EO) in OG were lower compared with WG. The number of TA, SA and EO in 20 D among 0 D, 20 D and 40 D stored at $5^{\circ}C$ were lowest. Especially, the SA and EO was $0.13{\sim}0.53$, 0.3-0.88, and 0.13-0.74 log cycle lower compared with raw flounder. The growth of TA, SA and EO separated from raw flounder in tryptic soy broth were completely inhibited by 0.1% CA. The anti-biotical effect of CA of two microorganisms SA and EO that separated from flounder, and the growth of all of them were 90% (SA), 96% (EO) inhibited at the 0.1% CA. The inhibition times at $37^{\circ}C$ in soy broth was 36 hr. However when CA was added directly to flounder, it appeared inhibition effect to 0.88 log cycle. The effect of CA was better when gills removed and 20% drying.

• Nutrition Research and Practice
• /
• v.10 no.1
• /
• pp.11-18
• /
• 2016

BACKGROUND/OBJECTIVES: Type 2 diabetes (T2D) is more frequently diagnosed and is characterized by hyperglycemia and insulin resistance. $\small{D}$-xylose, a sucrase inhibitor, may be useful as a functional sugar complement to inhibit increases in blood glucose levels. The objective of this study was to investigate the anti-diabetic effects of $\small{D}$-xylose both in vitro and stretpozotocin (STZ)-nicotinamide (NA)-induced models in vivo. MATERIALS/METHODS: Wistar rats were divided into the following groups: (i) normal control; (ii) diabetic control; (iii) diabetic rats supplemented with a diet where 5% of the total sucrose content in the diet was replaced with $\small{D}$-xylose; and (iv) diabetic rats supplemented with a diet where 10% of the total sucrose content in the diet was replaced with $\small{D}$-xylose. These groups were maintained for two weeks. The effects of $\small{D}$-xylose on blood glucose levels were examined using oral glucose tolerance test, insulin secretion assays, histology of liver and pancreas tissues, and analysis of phosphoenolpyruvate carboxylase (PEPCK) expression in liver tissues of a STZ-NA-induced experimental rat model. Levels of glucose uptake and insulin secretion by differentiated C2C12 muscle cells and INS-1 pancreatic ${\beta}$-cells were analyzed. RESULTS: In vivo, $\small{D}$-xylose supplementation significantly reduced fasting serum glucose levels (P < 0.05), it slightly reduced the area under the glucose curve, and increased insulin levels compared to the diabetic controls. $\small{D}$-xylose supplementation enhanced the regeneration of pancreas tissue and improved the arrangement of hepatocytes compared to the diabetic controls. Lower levels of PEPCK were detected in the liver tissues of $\small{D}$-xylose-supplemented rats (P < 0.05). In vitro, both 2-NBDG uptake by C2C12 cells and insulin secretion by INS-1 cells were increased with $\small{D}$-xylose supplementation in a dose-dependent manner compared to treatment with glucose alone. CONCLUSIONS: In this study, $\small{D}$-xylose exerted anti-diabetic effects in vivo by regulating blood glucose levels via regeneration of damaged pancreas and liver tissues and regulation of PEPCK, a key rate-limiting enzyme in the process of gluconeogenesis. In vitro, $\small{D}$-xylose induced the uptake of glucose by muscle cells and the secretion of insulin cells by ${\beta}$-cells. These mechanistic insights will facilitate the development of highly effective strategy for T2D.

• Journal of Ginseng Research
• /
• v.14 no.2
• /
• pp.291-296
• /
• 1990

Various rates of 2,4-D were sprayed on 2 and 3 year old ginseng plants as foliar spray to define the critical concentration. No apparent plant injury was noticable for those ginseng plants when application concentration of 2,4-D doubled the recommended dosage (70 ml/10a). Neither abnormal foliar change occurred nor any inhibition in leaf and stem growth was resulted for the plants treated with 2,4-D concentrated two times of the recommended dosage. When the rates of 2,4-D application were increased greater than this level, injury ratings increased linearly with the rates of 2,4-D application and plant you was inhibited. Ethylene gas was not produced from the ginseng plant treated with 2 times concentrated 2,4-D, however the ginseng plants produced 0.03 to 0.09 ppm ethylene gas when the rate of application were increased 3 and 4 times, respectively. On the other hand the soybean treated with the recommended amount of 21-D produced ethylene gas of 10-20 times higher compared with ginseng plants and died. Photosynthesis ability of the ginseng leaf was significantly decreased by 2,4-D foliar application but it was recovered 4 weeks after 2,4-D foliar treatment. The herbicide 2,4-D was applicated to 2,3 and 4 years old ginseng plants as foliar spray with the rates of 0.5, 1.0, 1.5 and 2.0 times of the recommended dosage to define the effects of 2,4-D on the plant growth and root yield of the ginseng. There were no significant differences in the leaf and stem growth between untreated and 2,4-D treated plant. Berry maturing of 3 and 4 year old ginseng was not influenced by 2,4-D. The root weight of 4 years old ginseng plant was not reduced by application of 2,4-D concenrated 2 times of the recommended dosage, Application time of the herbicide 2,4-D had no effects on the leaf or stem growth of 2,3 and 4 year old year old ginseng plants. When the ginseng seedling was treated with 2,4-D, detrimental phenomena as stem bending and docoration of seedling leaf margin occurred, but stem bending was recovered in a few day s. Keywords Panax ginseng C.A. Meyer, 2,4-D , herbicide.