• 대한금속재료학회지
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• 제49권1호
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• pp.17-24
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• 2011

To investigate the relationship between heat treatment in zirconium alloy tubing process and metallurgical characteristics of Zr-1Nb-0.69Sn-0.11Fe alloy tubes, mechanical and oxidation behaviors of tubes heat treated at different temperatures after the final pilgering were investigated. The stress strain curves exhibited the saturation behaviors in all heat treatment conditions ($460{\sim}600^{\circ}C$) in this study with the onset strain of saturation increased with increase of post-pilgering annealing temperature. The strength fell off rapidly with increasing annealing temperature. The ultimate strength of the low tin Zr-1Nb-0.69Sn-0.11Fe alloy with slightly higher iron and oxygen contents in this study was found to be higher than Zr-1Nb-1Sn-0.1Fe alloy. The oxidation experiments in steam condition revealed that the corrosion resistance of low tin Zr-1Nb-0.69Sn-0.11Fe alloy was better than the Zr-1Nb-1Sn-0.1Fe alloy with a higher Sn content. The weight gain of low tin Zr-1Nb-0.69Sn-0.11Fe alloy tubes gradually increased with the increasing annealing temperature possibly due to the decreased Nb content in the matrix because of the formation of ${\beta}-Nb$ particles.

• The Korean Journal of Physiology and Pharmacology
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• 제25권2호
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• pp.131-137
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• 2021

Aging is the process spontaneously occurred in living organisms. Cardiac fibrosis is a pathophysiological process of cardiac aging. Mangiferin is a well-known C-glucoside xanthone in mango leaves with lots of beneficial properties. In this study, rat model of cardiac fibrosis was induced by injected with 150 mg/kg/d D-galactose for 8 weeks. The age-related cardiac decline was estimated by detecting the relative weight of heart, the serum levels of cardiac injury indicators and the expression of hypertrophic biomakers. Cardiac oxidative stress and local inflammation were measured by detecting the levels of malondialdehyde, enzymatic antioxidant status and proinflammatory cytokines. Cardiac fibrosis was evaluated by observing collagen deposition via masson and sirius red staining, as well as by examining the expression of extracellular matrix proteins via Western blot analysis. The cardiac activity of profibrotic TGF-β1/p38/MK2 signaling pathway was assessed by measuring the expression of TGF-β1 and the phosphorylation levels of p38 and MK2. It was observed that mangiferin ameliorated D-galactose-induced cardiac aging, attenuated cardiac oxidative stress, inflammation and fibrosis, as well as inhibited the activation of TGF-β1/p38/MK2 signaling pathway. These results showed that mangiferin could ameliorate cardiac fibrosis in D-galactose-induced aging rats possibly via inhibiting TGF-β/p38/MK2 signaling pathway.

• Journal of Ginseng Research
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• 제45권2호
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• pp.287-294
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• 2021

Background: Ginsenoside Rb1 (G-Rb1), one of the major active compounds in Panax ginseng, has already been shown to reduce inflammation in various diseases. Osteoarthritis (OA) has traditionally been considered a degenerative disease with degradation of joint articular cartilage. However, recent studies have shown the association of inflammation with OA. In the present study, we investigated whether Rb1 had an antiinflammatory effect on monoiodoacetate (MIA)-induced OA in ovariectomized rats as a model of postmenopausal arthritis. Methods: G-Rb1 at a dosage of 3 and 10 ㎍/kg body weight was administered every 3 days intraarticularly for a period of 4 weeks to observe antiarthritic effects. Diclofenac (10 mg/kg) served as a positive control. Results: The administration of Rb1 significantly ameliorated OA inflammatory symptoms and reduced serum levels of inflammatory cytokines. Furthermore, G-Rb1 administration considerably enhanced the expression of bone morphogenetic protein-2 and collagen 2A and reduced the levels of matrix metalloproteinase-13 genes, indicating a chondroprotective effect of G-Rb1. G-Rb1 also significantly reduced the expression of several inflammatory cytokines/chemokines (interferon gamma (IFN-γ), monocyte chemoattractant protein-1 (MCP-1)/CCL-2, interleukin [IL]-1β, and IL-6). Histological analysis demonstrated that G-Rb1 significantly attenuated the pathological changes in MIA-induced OA in ovariectomized rats. Safranin O and toluidine blue staining further demonstrated that G-Rb1 effectively prevented the degradation of cartilage and glycosaminoglycans, respectively. Conclusion: Overall, our results suggest that G-Rb1 exerts cartilage protective effect on MIA-induced ovariectomized OA rats, by inhibiting inflammatory mediators such as IL-6, IL-1β, MCP-1/CCL-2, cyclooxygenase-2 (COX-2), and prostaglandin E₂ (PGE2). These results shed a light on possible therapeutic application of G-Rb1 in OA.

• 치위생과학회지
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• 제22권2호
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• pp.99-107
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• 2022

Background: Obesity weakens acquired immunity and causes infection. This study aimed to investigate the relationship between the inflammatory markers in the gingival crevicular fluid and serum and periodontal bacteria in saliva through obesity control for 4 weeks. Methods: Forty-six subjects with a body mass index (BMI) of ≥23 kg/m² stayed in the camp for 4 weeks, followed by exercise and a low salt-low fat diet. Body size measurements, oral examinations, blood, saliva, and gingival crevicular fluid were collected before and after the program. C-reactive protein (CRP) in serum, matrix metalloproteinase (MMP)-8, MMP-9, and interleukin (IL)-1β in the gingival sulcus fluid were measured. After extracting bacterial genomic DNA from saliva, the presence of periodontal bacteria were detected using Taq probe. The relationship of each index before and after the program was analyzed through paired t-test and partial correlation analysis. Results: Campylobacter rectus (Cr) increased after the program, and there was no significant change in other bacteria. Serum CRP and Fusobacterium nucleatum (Fn), Aggregatibacter actinomycetemcomitans, Cr, ratio of Fn, and ratio of Cr had a positive relationship at baseline; however, the relationship was not significant after the program. Ratio of Prevotella intermedia had a positive relationship with MMP-9, MMP-8, IL-1β at baseline. Moreover, the ratio of Treponema denticola and the ratio of Tannerella forsythia showed a positive relationship with MMP-8, MMP-9, and IL-1β. The relationship between the ratio of Porphyromonas gingivalis and IL-1β showed a constant positive relationship at baseline and after the program. Conclusion: Obesity control program in subjects with a BMI of ≥23 kg/m² accompanied by diet and exercise did not affect the changes in periodontal bacteria itself, but changes in the relationship between periodontal bacteria and serum CRP, the relationship between the inflammatory index in the gingival crevicular fluid and periodontal bacteria was observed.

• 한국발생생물학회지:발생과생식
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• 제25권4호
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• pp.257-268
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• 2021

Phthalates and their metabolites are well-known endocrine disrupting chemicals. Di-(2-ethylhexyl) phthalate (DEHP) has been widely used in industry and the exposing possibility to adult is high. In this study, DEHP was treated (133 ㎍/L and 1,330 ㎍/L in drinking water) according to the OECD test guideline 443 to mature female mice and their adrenal gland were examined for histological characteristics and steroidogenic gene expression. The wet weight of the adrenal gland was increased in all administrated groups compared to control. The diameter of zona fasciculata (ZF) was increased by DEHP in both outer ZF and inner ZF but there was no difference in morphology of the cells and arrangements into zona between groups. In addition, the arrangement of extracellular matrix was not different between control and DEHP groups. CYP11B1 was mainly localized at ZF and the intensity was not different between groups. DAX1 was localized in zona glomerulosa (ZG) and ZF, and its expression levels were decreased by DEHP administration. Its level was lower in DEHP133 group than DEHP1330 group. On the other hand, CYP17A1 was localized in ZG of DEHP1330 group. These results suggest that chronic low-dose DEHP exposing may modify the microstructure and function of the adrenal cortical cortex.

• 보건행정학회지
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• 제32권4호
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• pp.356-367
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• 2022

Background: The emergence of new infectious diseases threatens public health, increasing socioeconomic damage, and national risks. This study aimed to develop an evidence-based risk assessment tool to quickly respond to new infectious diseases. Methods: The risk elements were extracted by reviewing the risk assessment methods of the World Health Organization, United States, Europe, United Kingdom, and Germany, and the validity and priority of elements were determined through expert meetings and Delphi surveys. Then, the scale and level for each risk element were defined and a final score calculation method according to the risk evaluation result was derived. The developed risk assessment tool was verified using data at the time of domestic transmission of an emerging infectious disease. Results: In case of spread of actual infectious diseases, priority is determined based on the criticality of the elements in each area of transmissibility and severity, from which the weighted score of the risk assessment is derived. Then, the risk score for each element was calculated by multiplying the average value of the risk evaluation by its weight and the evaluation risk assessment score for the two areas was calculated. At last, the final score is plotted in a matrix where the x-axis indicates the transmissibility and the y-axis the severity and plotted on the coordinate plane for time series use. Conclusion: With respect to transmissibility and severity, this risk assessment method to respond to new and re-emerging infectious diseases enables rapid and evidence-based evaluation by quantitatively and qualitatively assessing various risk elements.

• Advances in concrete construction
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• 제14권5호
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• pp.355-368
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• 2022

This paper investigates the impact of length and volume fractions (VFs) of banana fibres (BFs) on the mechanical and physical properties of concrete. The mechanical properties were compressive strength, splitting tensile, flexural strength, and bond stress, while the physical properties were unit weight and absorption. The slump test was used to determine workability. The concrete's behaviour with BFs was studied using scanning electron microscopy. Experimental work of concrete mixtures with BFs of various lengths (12 mm, 25 mm, and 35 mm) and VFs (0%, 0.5%, 1.0%, and 1.5%) were carried out. The samples did not indicate any agglomeration of fibres or heterogeneity during mixing. The addition of BFs to concrete with VFs of up to 1.50% for all fibre lengths have a significant impact on mechanical properties, also the longer fibres performed better than shorter ones at all volume fractions of BFs. The mix10, which contain BFs with VFs 1.5% and length 35 mm, demonstrated the highest mechanical properties. The compressive strength, splitting tensile, flexural strength, and bond stress of the mix10 were 37.71 MPa, 4.27 Mpa, 6.12 MPa, and 6.75 MPa, an increase of 7.37%, 20.96%, 24.13%, and 11.2% over the reference concrete, which was 35.12 MPa, 3.53 MPa, 4.93 MPa, and 6.07 MP, respectively. The absorption is increased for all lengths by increasing the VFs up to 1.5%. Longer fibres have lower absorption, while shorter fibres have higher absorption. The mix8 had the highest absorption of 4.52%, compared to 3.12% for the control mix. Furthermore, the microstructure of concrete was improved through improved bonding between the fibres and the matrix, which resulted in improved mechanical properties of the composite.

• Applied Microscopy
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• 제52권
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• pp.5.1-5.10
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• 2022

The use of Pipelines for long-distance transportation of crude oil, natural gas and similar applications is increasing and has pivotal importance in recent times. High specific strength plays a crucial role in improving transport efficiency through increased pressure and improved laying efficiency through reduced diameter and weight of line pipes. TRIP-based high-strength and high-ductility alloys comprise a mixture of ferrite, bainite, and retained austenite that provide excellent mechanical properties such as dimensional stability, fatigue strength, and impact toughness. This study performs microstructure analysis using both Nital etching and LePera etching methods. At the time of Nital etching, it is difficult to distinctly observe second phase. However, using LePera etching conditions it is possible to distinctly measure the M/A phase and ferrite matrix. The fraction measurement was done using OM and SEM images which give similar results for the average volume fraction of the phases. Although it is possible to distinguish the M/A phase from the SEM image of the sample subjected to LePera etching. However, using Nital etching is nearly impossible. Nital etching is good at specific phase analysis than LePera etching when using SEM images.

• Journal of Microbiology and Biotechnology
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• 제33권2호
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• pp.235-241
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• 2023

Hyaluronidase (HAase) can enhance drug diffusion and dissipate edema by degrading hyaluronic acid (HA) in the extracellular matrix into unsaturated HA oligosaccharides in mammalian tissues. Microorganisms are recognized as valuable sources of HAase. In this study, a new hyaluronate lyase (HAaseD) from Bacillus sp. CQMU-D was expressed in Escherichia coli BL21, purified, and characterized. The results showed that HAaseD belonged to the polysaccharide lyase (PL) 8 family and had a molecular weight of 123 kDa. HAaseD could degrade chondroitin sulfate (CS) -A, CS-B, CS-C, and HA, with the highest activity toward HA. The optimum temperature and pH value of HAaseD were 40℃ and 7.0, respectively. In addition, HAaseD retained stability in an alkaline environment and displayed higher activity with appropriate concentrations of metal ions. Moreover, HAaseD was an endolytic hyaluronate lyase that could degrade HA to produce unsaturated HA oligosaccharides. Together, our findings indicate that HAaseD from Bacillus sp. CQMU-D is a new hyaluronate lyase and with excellent potential for application in industrial production.

• 대한한방내과학회지
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• 제43권6호
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• pp.1089-1104
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• 2022

Objective: The aim of this study was to identify the efficacy and underlying mechanism of cloves as an osteoarthritis (OA) treatment in a monosodium iodoacetate (MIA)-induced rat OA model. Osteoarthritis (OA) is nowadays one of the most prevalent degenerative joint diseases. Methods: Sprague-Dawley rats treated with MIA (50 μL; 80 mg/mL) were used as in vivo OA models. Cloves (100 and 200 mg/kg b.w.) were administered orally once daily for 2 weeks from 7 days after MIA injection. Changes in hindpaw weight distribution (HWD) were measured as a joint discomfort index. Activation markers related to inflammatory responses and cartilage degeneration in the right knee joints were evaluated by serum analysis and western blotting. Results: HWD decreased in the MIA control group but showed a dose-dependent elevation after clove treatment. Clove treatment inhibited inflammatory factors by PI3K/Akt/NF-κB signaling pathways, while also activating antioxidant factors through Sirt1/AMPK signaling pathways. Clove treatment also suppressed matrix metalloproteinase (MMP) overexpression and significantly increased the levels of tissue inhibitors of metalloproteinases (TIMPs). Conclusions: Treatment with cloves effectively reversed MIA-induced effects. Therefore, clove treatment could have the potential to protect against or treat OA.