• 한국식품조리과학회지
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• 제4권1호
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• pp.47-52
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• 1988

녹차의 품종, 채엽시기, 가공방법별에 따라 13종류의 한국산 녹차시료를 조제하고 이들 시료의 이화학적 성질을 측정한 결과는 다음과 같다. 1. 수활, 회분, 가용성 고형분 및 조지방 함량은 대체적으로 품종, 차엽의 채취시기 및 가공방법의 상위에 따른 큰 차이점은 나타나지 않았지만 조단백질의 경우에서는 삽목 Yabukida 품종 1번 차의 볶음과 찐 것에서 각각 30.8%, 31.3%이던 것이 2, 3번차로 갈수록 점차 감소하여 4번차의 경우에서는 각각 18.8%, 16.0% 이었다. 이러한 경향은 다른 품종에서도 유사한 경향을 나타내었다. 품종별에 따른 변화도 크게 나타났다. 조섬유에서는 채엽시기에 따라 증가하는 경향을 나타내었다. 2. 표면색도는 볶음 차보다 찐 차가 보다 밝은 녹황색을 띄며 채엽시기가 늦을수록 밝은 황색을 나타내었다. 또한 클로로필함량은 찐 차의 경우가 볶은 차보다 높았고, 채엽시기에 따라 감소의 경향을 보였으나 삽목 Yabukida 4번 차의 경우에서는 증가하였다. 3. 탄닌의 함량은 볶음의 경우 채엽시기가 늦을수륵 증가하였지만 찐 차의 경우 그런 경향이 나타나지 않았으며 theaflavin과 thearubigin 함량은 평균하여 각각 0.07% 및 2.27%이었고 산화중합물비는 평균 0.22이었다. 4. Methylxanthine류에서는 caffeine이 주성분으로 94∼98%를 차지하였으며 볶음차의 caffeine 함량이 높았다. 베니호마래의 caffeine 함량은 다른 품종보다 낮았다. 5. 녹차의 환원당은 0.1% 내외로 거의 일정하였으며 유리당의 경우 삽목 Yabukida가 다른 품종에 비해서 sucrose 함량이 높게 나타났다. 6. 녹차중의 유기산은 succinic, malic, shikimic, citric, quinic, gallic, oxalic 및 malonic acid의 8종류이었으며 이중 quinic acid의 함량이 높았다. 삽목 Yabukida 품종에서는 채엽시기가 빠른 녹차에서는 malic acid 함량이 매우 낮은 반면 oxalic acid는 채엽시기가 늦을수록 감소하여 미량으로 검지되었다.

• 공업화학
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• 제31권3호
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• pp.277-283
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• 2020

본 연구는 건자재용 목재의 연기 유해성평가에 대하여 연기성능지수-II (SPI-II), 연기성장지수-II (SGI-II)를 중심으로 조사하였다. 시험편은 삼나무, 가문비나무, 나왕, 적송을 사용하였다. 연기 특성은 시험편 목재에 대하여 콘칼로리미터(ISO 5660-1) 장비를 이용하여 조사하였다. 연소반응 후 측정된 연기성능지수-II는 적송을 기준으로 1.31~2.15배 증가하였다. 연기성능지수-II에 의한 화재위험성은 가문비나무, 나왕, 삼나무, 적송의 순서로 증가하였다. 연기성장지수-II는 삼나무를 기준으로 1.18~2.55배 증가하였다. 연기성장지수-II에 의한 화재위험성은 삼나무, 가문비나무, 나왕, 적송의 순서로 높아졌다. CO 평균농도는 59~133 ppm이었으며 이 결과는 미국직업안전위생관리국(occupational safety and health administration, OSHA)의 허용기준(permissible exposure limits, PEL)인 50 ppm 보다 높게 나타났다. 결론적으로 적송과 같이 휘발성 유기물질을 다랑 함유한 목재는 연기성능지수-II가 낮고, 연기성장지수-II가 높으므로 화재로 인한 연기유해성이 높은 것으로 이해된다.

• 상하수도학회지
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• 제20권4호
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• pp.545-558
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• 2006

The current conditions of large water mains are evaluated by deteriorations and the causes of deterioration are investigated through visual assessments in the field, mechanical tests and analysis of chemical compositions in laboratory for each pipe material, unlined cast iron pipes (CIPs), ductile iron pipes (DCIPs) and steel pipes (SPs) Tubercles and scales from internal and external corrosion of unlined cast iron pipes were identified as the causes of functional performance limitations in large water mains. It is investigated that main causes of internal and external corrosion of water pipes are from lots of depositions of organic and inorganic substances on pipe surface, concentrated pitting, and uniform corrosion by local or global exfoliation or detachment of lining and coatings of DCIPs and SPs. Internal and external corrosion depths of CIPs were higher than those of DCIPs and SPs. Consequently, total corrosion rate summed internal and external corrosion rates of CIPs also were shown to be higher than those of DCIPs and SPs. The failure time from hole generation of CIPs by total corrosion rate was predicted to be taken sixteen years, and DCIPs and SPs were twenty-six years and one hundred and fifty three years. And longitudinal deflection of investigated water mains were not happened and mechanical strengths such as tensile strength, elongation, and hardness also were mostly suited to Korea Standards. It was thought that the weakness of tensile strength of one sample(S-11) was, however, due to higher carbon contents(%) in CIPs. Pipe deterioration score of S-46 was 55.2 and was preferentially assessed to be rehabilitated.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권5호
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• pp.382-390
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• 2006

Various microorganisms were isolated from the surface waters and sediments of eutrophic lakes and reservoirs in Korea to enable an investigation of bacteria having algal lytic activities against Anabaena flos-aquae when water blooming occurs and to study enzyme profiles of algal lytic bacteria. Two bacterial strains, AFK-07 and AFK-13, were cultured, characterized and identified as Acinetobacter johnsonii and Sinorhizobium sp., respectively. The A. johnsonii AFK-07 exhibited a high level of degradatory activities against A. flos-aquae, and produced alginase, caseinase, lipase, fucodian hydrolase, and laminarinase. Moreover, many kinds of glycosidase, such as ${\beta}-galactosidase,\;{\beta}-glucosidase,\;{\beta}-glucosaminidase,\;and\; {\beta}-xylosidase$, which hydrolyzed ${\beta}-O-glycosidic$ bonds, were found in cell-free extracts of A. johnsonii AFK-07. Other glycosidases such as ${\alpha}-galactosidase,\;{\alpha}-N-Ac-galactosidase,\;{\alpha}-mannosidase,\; and\;{\alpha}-L-fucosidase$, which cleave ${\alpha}-O-glycosidic$ bonds, were not identified in AFK-07. In the Sinorhizobium sp. AFK-13, the enzymes alginase, amylase, proteinase (caseinase and gelatinase), carboxymethyl-cellulase (CMCase), laminarinase, and lipase were notable. No glycosidase was produced in the AFK-13 strain. Therefore, the enzyme system of A. johnsonii AFK-07 had a more complex mechanism in place to degrade the cyanobacteria cell walls than did the enzyme system of Sinorhizobium sp. AFK-13. The polysaccharides or the peptidoglycans of A. flos-aquae may be hydrolyzed and metabolized to a range of easily utilized monosaccharides or other low molecular weight organic substances by strain AFK-07 of. A. johnsonii, while the products of polysaccharide degradation or peptidoglycans were more likely to be utilized by Sinorhizobium sp. AFK-13. These bacterial interactions may offer an alternative effective approach to controlling the water choking effects of summer blooms affecting our lakes and reservoirs.

• Journal of Periodontal and Implant Science
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• 제47권6호
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• pp.388-401
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• 2017

Purpose: The physicochemical properties of a xenograft are very important because they strongly influence the bone regeneration capabilities of the graft material. Even though porcine xenografts have many advantages, only a few porcine xenografts are commercially available, and most of their physicochemical characteristics have yet to be reported. Thus, in this work we aimed to investigate the physicochemical characteristics of a porcine bone grafting material and compare them with those of 2 commercially available bovine xenografts to assess the potential of xenogenic porcine bone graft materials for dental applications. Methods: We used various characterization techniques, such as scanning electron microscopy, the Brunauer-Emmett-Teller adsorption method, atomic force microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and others, to compare the physicochemical properties of xenografts of different origins. Results: The porcine bone grafting material had relatively high porosity (78.4%) and a large average specific surface area (SSA; $69.9m^2/g$), with high surface roughness (10-point average roughness, $4.47{\mu}m$) and sub-100-nm hydroxyapatite crystals on the surface. Moreover, this material presented a significant fraction of sub-100-nm pores, with negligible amounts of residual organic substances. Apart from some minor differences, the overall characteristics of the porcine bone grafting material were very similar to those of one of the bovine bone grafting material. However, many of these morphostructural properties were significantly different from the other bovine bone grafting material, which exhibited relatively smooth surface morphology with a porosity of 62.0% and an average SSA of $0.5m^2/g$. Conclusions: Considering that both bovine bone grafting materials have been successfully used in oral surgery applications in the last few decades, this work shows that the porcinederived grafting material possesses most of the key physiochemical characteristics required for its application as a highly efficient xenograft material for bone replacement.

• Asian-Australasian Journal of Animal Sciences
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• 제28권5호
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• pp.620-631
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• 2015

A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC $43971^T$, Micrococcus luteus ATCC $4698^T$ and Escherichia coli ATCC $11775^T$ were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at $100^{\circ}C$), but the antimicrobial activity was eliminated after treatment at $121^{\circ}C$ for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory.

• Ocean and Polar Research
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• 제25권4호
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• pp.653-662
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• 2003

Changes in the area of geo-ecosystem $(62^{\circ}09'S,\;58^{\circ}31'w)$ reflect climatic changes in the South Shetland Islands. Air temperature and deglaciation will increase. The ice-free space area at the SSSS 8- (ASPA 121) site has enlarged threefold during the last 21 years, thus creating conditions for inhabitation and succession. Wind, water and snow play important roles in transportation of geochemical components. They distribute nutrients, mineral substances, seeds, fragments of plants and animals, etc. Plant and animal colonization is patchy and it happens at random in an 'island' - like manner. The colonization pattern is dependant, to a high degree on physical factors. The newly uncovered ice-free areas are at first inhabited by a vascular plant known as the Deschampsia antarctica. The border of the land-oasis with Admiralty Bay is the place where the processes related to animal feeding at the sea and reproduction on the land take place. Bird colonies and pinniped lairs form centers of fertilization surrounded by high chemical gradients dependent on the direction of the flow of nutrients $(e.g.\;NH_4)$. During the last 25 years, the numbers of penguins in this region have decreased, and thus the amount of materials excreted on land has diminished. The numbers of fur seals change in multi-annual cycles, and their migration into this area is related to the E1 $Ni\~{n}o$ phenomenon. The numbers of elephant seals in the area did not change. Organic matter deposited by the sea onto the shore are a source of nutrients and deficient chemical elements on land. Mineral matter is washed out into the waters of Admiralty Bay. These processes change seasonally, and multi annually. Negative effects on the environment at Arctowski Station induced by man are slight, but noticeable nevertheless. Physical processes have the largest influence on the living conditions and distribution of plants and animals, and as a consequence, on the functioning of the geo-ecosystem in the coastal-shore zone of the Maritime Antarctic.

• Journal of Nutrition and Health
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• 제31권6호
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• pp.1014-1023
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• 1998

The influences of fish oil and different levels of vitamin I supplement on hepatocellular chemical carcinogenesis have been studied. Male Sprague-Dawley rats received diethylnitrosamine (DEN)(200mg/kg body weight) and were subjected to two-thirds partial hepatectomy to induce murine chemical hepatocarcinogenic procedure. Placental glutathione S-transferase(GST-P) positive foci area, antioxidant enzymes(Cu/Zn-superoxide dismutase(SOD), catalase, glutathione reductase (GR), total- glutathione peroxidase (TGPx), glutathione S -transferase (GST)), glucose 6-phosphatase (G6Pase) activities, and lipid peroxidation of microsomes(thiobarbituric acid reactive substances (TBARS)) were measured. Experimental animals were fed 15% corn or fish oil with 0, 40, 1,000, 10,000IU vitamin E /kg diet for 8 weeks. Vitamin E supplements decreased the area of GST-P positive foci in both groups. The higher the vitamin E levels, the smaller the area of GST-P positive foci were noticed. Compared to 0 IU vitamin E, 40 IU in corn oil and 1,000 IU in fish oil groups were effective in decreasing G57-P positive foci area. Fish oil groups tended to have smaller area of GST-P positive foci. fish oil groups showed lower body weight, lower activities of Cu/Zn-SOD and TGPx, higher TBARS contents, higher activities of GST, catalase, G6Pase, GR and higher liver/body ratio than corn oil groups. As the level of vitamin I increased, GST-P positive foci count, catalase activities, and TBARS tended to decrease. G6Pase activities tended to increase in both groups. At higher vitamin E levels, GST activities tended to decrease in fish oil groups. These results suggest that vitamin I has suppressive offects on hepatocellular chemical carcinogenesis probably through antioxidant eH:cts decreasing TBARS contents, $H_2O$$_2$, and organic peroxides. fish oil tended to have greated suppressive offects than corn oil on hepatocellular carcinogenesis. (Korean J Nutrition 31(6) : 1014-1023, 1998)

• 한국항해항만학회지
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• 제38권6호
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• pp.601-606
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• 2014

본 연구에서는 선박에서 발생하는 오 폐수의 처리를 위하여 SBR공정에 유효미생물을 주입하는 변법을 이용하여 Lab scale 실험을 수행하였다. 유해물질 유입에 따른 생물학적 처리 장치의 효율 저하 문제를 해결하기 위하여 SBR공정에 유효미생물을 주입하는 변법은 크루즈선이라는 특수 환경과의 접목성과 생물학적 처리 시 야기될 수 있는 문제를 대비하기 위한 대안으로 선박환경에 매우 적합한 공정으로 평가되었다. 슬러지 관찰 결과 기존의 활성슬러지에 유효미생물의 주입함으로써 슬러지의 안정성을 확보할 수 있었으며, 슬러지의 EPS 함량도 40% 이상 높아진 것을 확인할 수 있었다. 또한 슬러지의 미생물 분석 결과 유효미생물 주입으로 인해 수처리에 유리한 미생물종이 다수 출현하여 휘발성 유기화합물과 같은 유기 유해물질이 생분해되어 안전한 물질로 전환되는 것을 확인할 수 있었으며. 중금속과 같은 무기 유해물질도 중금속의 종류와 유입농도에 영향을 받지 않고 70% 이상의 안정적인 처리 효율도 확보할 수 있는 것으로 확인되었다.

• 한국응용과학기술학회지
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• 제1권1호
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• pp.33-36
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• 1984

백쥐의 사료(飼料)에 석이버섯의 수용성(水溶性) 및 EtOH 추출물(抽出物)을 지(知)하여 지질대사(脂質代謝) 및 cholesterol대사(代謝)에 미치는 영향을 검토(檢討)한 결과(缺課), 다음과 같은 결론(結論)을 얻었다. (1) 간희(肝曦) 및 혈(血) cholesterol 저하작용(低下作用)에 관해서는 수용성(水溶性) 추출물(抽出物)이나 EtOH 추출물(抽出物)이 동시(同時)에 유핵(有劾)하다는 결과(結果)를 얻었다. 그리고 EtOH 추출물(抽出物)이 수용성(水溶性) 추출물(抽出物)보다 약간 높은 경향을 보였다. (2) 이 cholesterol 저하작용(低下作用)에 관여하는 유핵성출(有劾性物)은 물이나 EtOH의 추출(抽出)에 따라서 어느 쪽의 추출액으로도 이행(移行)되는 성질(性質)을 가지고 있다고 추정(推定)된다.