• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.1652-1655
• /
• 2008

Indoor air quality (IAQ) of subway becomes a key issue as the IAQ guidelines for public transportation published. There are two major sources regarding IAQ of subway; One is the sources coming from outdoor air and the other is sources of inside. Particulate matters smaller than 10 micrometer (PM10) and carbon dioxide ($CO_2$) are recognized as the one of the most severe pollutants in Korea. The source of PM10 is mainly coming from outdoor air, however, the source of $CO_2$ is coming from passengers exhaust. According to the guidelines, the level of $CO_2$ should be lower than 2500ppm for normal operating time and lower than 3500ppm for rush hour. In order to satisfy these guidelines, the volume of mechanical ventilation should be increase which consumes extra energy for heating or cooling. Therefore, the optimum volume of mechanical ventilation should be calculated for energy saving. In this study, we measured the natural ventilation rate by door-opening which can reduce the load of mechanical ventilation. The $CO_2$ generator and sensors were used to measure the change of $CO_2$ by periodic door-opening of subway.

• Journal of Animal Science and Technology
• /
• 제49권5호
• /
• pp.621-632
• /
• 2007

항생제 대체물질로서 가축용 생균제를 개발하기 위하여, 오리의 소장 및 맹장으로부터 416주의 미생물을 분리하였으며, 항균물질인 박테리오신을 생산하는 13주를 최종적으로 선발하였다. 선발균주들은 Lactobacillus salivarius 1주, Lactobacillus plantarum 1주, Pediococcus pentosaceus 1주, Enterococcus 7주, 그리고 3주의 E. coli로 동정되었으며, 복합생균제를 제조할 목적으로 상기 균주중 5균주에 대한 박테리오신 및 생균제적인 특성를 조사하였다. 유산균인 Lact. salivarius JWS 58, Ent. faecium JWS 833, 그리고 Ped. pentosaceus JWS 939는 식품관련 병원성 균주로 알려진 Listeria mono- cytogenes에 대하여 강한 항균능력을 나타냈으며, 상기 균주의 cell-free supernatant를 단백질 분해효소 처리시 대부분이 병원균 억제활성을 상실하였다. 선발균주인 E. coli JWS 108은 그람음성균주인 E. coli와 Staphylococcus aureus 균주에 대한 생육억제활성을 나타냈다. 또한 Lact. salivarius JWS 58균주와 Ent. faecium JWS 833균주는 각각 Lactobacillus sp. 및 Enterococcus sp. 균주에 대하여 억제활성을 지니고 있었다. Lact. salivarius JWS 58균주는 pH 2.5 완충용액에서 2시간 동안 50% 이상 생존하였으며, pH 2.0 이하에서는 대부분의 선발균주들이 사멸하였다. 그러나 선발균주 모두 0.5% 담즙산 농도까지 아무런 억제현상없이 정상적으로 성장하였다. Ped. pentosaceus JWS 939와 Lact. plantarum JWS 1354 균주는 상대적으로 높은 amylase와 cellulase 효소 활성를 나타냈으며, E. coli JWS 108 균주는 낮은 효소활성을 보였다. Protease 및 lipase 효소 활성은 5균주 모두 유사하게 나타내었다.

• Journal of Animal Science and Technology
• /
• 제51권2호
• /
• pp.135-142
• /
• 2009

본 실험은 비육돈에 저에너지 사료를 급여했을 때 도살체중이 성장효율과 도체 품질에 미치는 영향을 조사하여 적정 도살체중을 추정할 목적으로 수행되었다. (Yorkshire $\times$ Landrace) $\times$ Duroc 교잡종 암퇘지와 거세돼지에게 3,060 kcal DE/kg의 저에너지사료를 생체중 80 kg부터 급여하여 110, 125, 혹은 135 kg에 도살한 다음 한국에서 선호도가 가장 높은 부위인 삼겹살과 선호도가 가장 낮은 뒷다리 및 등심에 대한 이화학적 특성과 관능검사를 실시하였다. 일당증체량과 일당사료섭취량은 공히 125 및 135 kg 구가 110 kg 구보다 높았고, 사료효율은 반대로 110 kg 구가 높았다(P<0.01). 등지방두께는 도살체중이 증가하면서 증가하였고(P<0.01와 P<0.05), 암퇘지보다 거세돼지에서 높아(P<0.01) 125 kg 거세돼지의 등지방두께(24.6 mm)는 135 kg 암퇘지의 수치(24.2 mm)와 비슷하였다. 삼겹살, 뒷다리 및 등심의 이화학적 특성은 도살체중의 영향을 거의 받지 않았으나, 110 kg과 125 kg 도살체중 사이 뒷다리의 적색도 증가(P<0.05)는 주목할만 하였다. 삼겹살에 대한 관능평가에서는 이 부위의 매우 중요한 품질 특성인 지방층:근육층 비율이 125 kg 도살체중에서 가장 높았으나(P<0.05) 전체적인 기호도는 도살체중과 무관하였다. 뒷다리와 등심부위에서는 상강도는 110 kg과 125 kg 도살체중 사이 증가한(P<0.01) 반면 색깔, 향, 이상취 및 육즙참출 정도는 도살체중의 영향을 받지 않았다. 또한 등심 부위의 전체적인 기호도는 110 kg과 125 kg 도살체중 사이 증가하였다(P<0.05). 가열육에 대한 관능평가에서는 110 kg과 125 kg는 색깔, 향, 이상취, 다즙성, 연도, 맛 및 전체적인 기호도 중 어느 품질 특성도 출하체중 변화로 인해 변하지 않았다. 결론적으로, 본 연구에 쓰인 저에너지 사료를 급여할 때 본 연구에 쓰인 돈군의 암퇘지와 거세돼지의 적정 도살체중은 각각 125~135 kg 및 125 kg 수준이다.

• 한국동물위생학회지
• /
• 제30권3호
• /
• pp.437-443
• /
• 2007

This study was carried out to investigate the sorts and the quantity of preservatives in 2,575 samples of 10 kind products which had been sold in the markets from 2004 to 2006. These analyses were done using HPLC. By the result of Investigation, the most frequently detected preservative was sorbic acid in 222 cases. Detection rate of sorbic acid was 8.62%. Dehydroacetic acid (DHA) was detected in 8 cases among 36 butter samples and one of 278 sausage samples. Detection rate of DHA was 0.0035%. In detail, the detection rate was 71.5% (88/123) in dried meat, 22.2% (8/36) in processed butter, 17.3% (48/278) in sausage, 10.4% (17/163) in canned meat etc., 7.9% (49/619) in ham, 7.48% (19/254) in processed cheese and 4% (2/49) in bacon, respectively. The content range of sorbic acid and its average in each of the processed meat and milk products are as follows: $ND{\sim}1.64 g/kg$, 0.26 g/kg in dried meat, $ND{\sim}1.34 g/kg$, 0.114g/kg in sausage, $ND{\sim}0.41g/kg$, 0.015 g/kg in canned meat etc., $ND{\sim}1.37 g/kg$, 0.038g/kg in ham, $ND{\sim}1.63g/kg$, 0.056 g/kg in processed cheese, $ND{\sim}0.57 g/kg$, 0.022 g/kg in bacon, respectively. Amount of detected DHA was less than 0.23 g/kg, and its average was 0.022 g/kg in processed butter.

• Asian-Australasian Journal of Animal Sciences
• /
• 제31권8호
• /
• pp.1366-1372
• /
• 2018

Objective: A disintegrin and metallopeptidase with thrombospondin motifs type 8 (ADAMTS8) is crucial for diverse physiological processes, such as inflammation, tissue morphogenesis, and tumorigenesis. The chicken ADAMTS8 (chADAMTS8) gene was differentially expressed in the kidney following exposure to different calcium concentrations, suggesting a pathological role of this protein in metabolic diseases. We aimed to examine the molecular characteristics of chADAMTS8 and analyze the gene-expression differences in response to toll-like receptor 3 (TLR3) stimulation. Methods: The ADAMTS8 mRNA and amino acid sequences of various species (chicken, duck, cow, mouse, rat, human, chimpanzee, pig, and horse) were retrieved from the Ensembl database and subjected to bioinformatics analyses. Reverse-transcription polymerase chain reaction (RT-PCR) and quantitative PCR (qPCR) experiments were performed with various chicken tissues and the chicken fibroblast DF-1 cell line, which was stimulated with polyinosinic-polycytidylic acid (poly[I:C]; a TLR3 ligand). Results: The chADAMTS8 gene was predicted to contain three thrombospondin type 1 (TSP1) domains, whose amino acid sequences shared homology among the different species, whereas sequences outside the TSP1 domains (especially the amino-terminal region) were very dif­ferent. Phylogenetic analysis revealed that chADAMTS8 is evolutionarily clustered in the same clade with that of the duck. chADAMTS8 mRNA was broadly expressed in chicken tissues, and the expression was significantly up-regulated in the DF-1 cells in response to poly(I:C) stimulation (p<0.05). These results showed that chADAMTS8 may be a target gene for TLR3 signaling. Conclusion: In this report, the genetic information of chADAMTS8 gene, its expression in chicken tissues, and chicken DF-1 cells under the stimulation of TLR3 were shown. The result suggests that chADAMTS8 expression may be induced by viral infection and correlated with TLR3-mediated signaling pathway. Further study of the function of chADAMTS8 during TLR3-dependent inflammation (which represents RNA viral infection) is needed and it will also be important to examine the molecular mechanisms during different regulation, depending on innate immune receptor activation.

• 한국식품영양학회지
• /
• 제32권6호
• /
• pp.636-642
• /
• 2019

The purpose of this study was to examine biological activities, including total contents of polyphenol, antioxidant activities, inhibitory activities of tyrosinase, and protective effect against oxidative stress in the HepG2 cells of ethanol extracts from wheat sprout. The antioxidant activity of extracts was determined by ABTS and DPPH radical scavenging activities. Ethanol extracts were tested using different ethanol concentrations (0%, 30%, 50%, 80% and 95%, respectively). The highest amount of total polyphenol was extracted by 50% and 80% ethanol which was 26.3 and 26.8 mg gallic acid equivalents/g sample, respectively. High levels of ABTS and DPPH radical scavenging activity were found in 50% ethanol (26.7 and 15.0 mg TEAC/g sample, respectively) and 80% (24.3 and 16.1 mg TEAC/g sample, respectively) ethanol extracts. Also, 50% and 80% ethanol extracts indicated higher inhibitory activities of tyrosinase compared with other extracts. In the cell-based assay, pre-treatment of the HepG2 cells with wheat sprout extracts prevented the cell damage induced by TBHP (tert-butyl hydroperoxide). The results of this study indicate that wheat sprout has significantly higher diverse biological activities and apparently has significant health benefits.

• 대한치과기공학회지
• /
• 제22권1호
• /
• pp.69-78
• /
• 2000

The microstructure and corrosion behavior of commercially dental casting gold alloys were investigated to clarify the effect of burn-out temperature and cooling rate. In the case of water quenching after casting, only the αphase, which is typical dendritic microstructure of golda alloy, was detected. However, the precipitates along the grain boundary were detected only at the slow cooling rate and they increased inversely proportional to the burn-out temperature. This might be due to the time difference which solute atom could diffuse. EPMA and SEM results also demonstrated that the precipitate should be lamellar structure consisted of Ag rich phase(${\alpha}_1$) and Cu rich phase (${\alpha}_2$). In terms of corrosion, the galvanic coupling was formed due to the difference of composition between precipitates and matrix at the slow cooling rate. In the case of water quenching, the critical current density($i_p$) which indicate the degree of corrosion was lowest at $650^{\circ}C$ and below the burnout temperature, $i_p$ increased with it because of the effect of grain boundary segregation. But above the temperature, $i_p$ increased with it. This may be due to the strain field effect by residual thermal stress.

• Mycobiology
• /
• 제40권3호
• /
• pp.164-167
• /
• 2012

The effects of aeration through lid filters on the hyphal growth of Lentinula edodes (oak mushroom) in sawdust cultivation bags were investigated. The aeration treatment levels were traditional 27 mm hole cotton plugs, cotton balls and combinations of seven hole sizes ${\times}$ two hole positions (up and under) in the lids covering plastic bags containing 1.4 kg sawdust medium at 63% moisture that had been autoclaved for one hour and inoculated with sawdust spawn of L. edodes strain 921. Aeration treatment effects were measured based on the $CO_2$ concentration at the 15th wk, as well as the hyphal growth rate and degree of weight loss of bags every 14 days for 15 wk. In bags with traditional cotton plugs, the $CO_2$ concentration was $3.8{\pm}1.3%$, daily mean hyphal growth was $2.3{\pm}0.6mm$ and daily mean weight loss was $0.84{\pm}0.26g$. In the bags with 15 mm diameter holes, the $CO_2$ concentration was $6.0{\pm}1.6%$, daily hyphal growth was $2.8{\pm}0.2mm$ and daily weight loss was $0.86{\pm}0.4g$. The bags with 15 mm holes had a higher $CO_2$ concentration and lower water loss than bags with other hole sizes, but the hyphal growth was not significantly different from that of other bags. The weight loss of bags increased proportionally relative to the lid hole sizes. Taken together, these results indicate that traditional cotton plugs are economically efficient, but 15 mm hole lids are the most efficient at maintaining hyphal growth and controlling water loss while allowing $CO_2$ emissions.

• 한국식품영양학회지
• /
• 제33권2호
• /
• pp.167-173
• /
• 2020

To increase the functional material content of soybean, a repetitive steaming and drying process was used. We investigated the changes in the total polyphenol content, the antioxidant activity, and the angiotensin-I converting enzyme (ACE) inhibition in soybean following nine rounds of steaming and drying. Soybean was steamed 9 times for 2 h and then dried 9 times from 55℃ to 73℃ for 3 h. The total polyphenol content in the soybean reached a maximum value of 60.47 mg GAE eq./100 g at 73℃ while the total polyphenol content in the raw soybean reached 25.17 mg GAE eq./100 g. In the raw soybean samples, the DPPH radical scavenging activity (5 mg/mL) was 8.04% but it increased by 43.29% after drying 9 times to 73℃. ABTS radical scavenging activity also improved following 9 rounds of steaming and drying. ACE inhibitory activity of the soybean dried 9 times at 73℃ was 58.94% at 10 mg/mL. These results showed that steaming and drying soybean 9 times enhanced the antioxidant activity and the ACE inhibitory activity of soybean. Therefore, more research on the biological and anti-hypertensive activity of soybean using this steaming and drying method is necessary.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제15권3호
• /
• pp.197-206
• /
• 2015

Failure analysis of pre-insulated pipe (SPPS 380, 400A) transporting high temperature water ($95{\sim}110^{\circ}C$) for a plant was carried out. The damaged area (${\Phi}5mm$) of pre-insulated pipe was found only on welds. The chemical composition of damaged pipe meets specification of carbon steel pipes for pressure service (KS D 3562). As results of microstructure analysis, crack propagated from outer to inside after pitting corrosion occurred on the outside surface. The non-metallic inclusion existed on the end of crack. And the non-metallic inclusion continuously and linearly formed along with the bond line of welds. Based on SEM-EDS analysis, the nonmetallic inclusions have higher Manganese (Mn) and Oxygen (O) content but sulfur (S) was not detected. As results of water quality analysis, hydrogen ion concentration and minerals like Fe, Mg, Si were in low level. But the content of dissolved oxygen (11.2 ppm) was slightly higher than that of standard. It seems that the cause of damaged pipe is grooving corrosion due to MnO inclusion formed on bond line and corrosion took place nearby welds.