• 물류혁신 컨퍼런스
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• 제11권3호
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• pp.97-112
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• 2003

• 정보처리학회지
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• 제9권6호
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• pp.72-78
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• 2002

• 정보처리학회지
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• 제6권5호
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• pp.143-146
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• 1999

• 한국잠사곤충학회지
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• 제32권2호
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• pp.85-88
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• 1990

춘기 뽕나무의 수액이동 시기를 구명하기 위하여 1981년, 1982년 그리고 1990년 3년에 걸쳐 3월중순부터 4월중순까지 1개월 동안 3일 간격으로 개량뽕, 청올뽕 그리고 홍올뽕의 가지를 채취하여 피부와 목부의 수분율을 측정하였다. 1. 수액이동은 1981년 지표 20cm, 지온이 10.1$^{\circ}C$인 4월 8일경에, 1982년 8.3$^{\circ}C$인 4월 2일경에, 1990년에는 8.7$^{\circ}C$인 3월 25일경에 일어나서, 해에 따라 1.8$^{\circ}C$ 15일 차를 보였다. 2. 지표 20cm 지온 8$^{\circ}C$ 이하로 떨어지면 목부의 수분율은 감소하거나 피부의 수분율은 현상유지 내지는 증가하는 것으로 보아 뿌리로부터 수분 흡수가 감소되면 목부의 수분이 피부로 이동.보충되는 것으로 보인다. 3. 수액이동은 3월 1일 이후 지표하 20cm의 지온이 영상으로 올라간 때부터 합산하여 적산온도가 18$0^{\circ}C$ 정도 되는 시기에 일어났다.

• 한국토양비료학회지
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• 제45권6호
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• pp.910-919
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• 2012

The role of inorganic nitrogen assimilation in the production of amino acids, organic acids and soluble sugars is one of the most important biochemical processes in plants, and, in order to achieve normally, nitrate uptake and assimilation is essential. For this reason, the characterization of nitrate assimilation and metabolite composition from leaves, roots and xylem sap of tomato (Solanum lycopersicum) was investigated under different nitrate levels in media. Tomato plants were grown hydroponically in liquid culture under five different nitrate regimes: deficient (0.25 and 0.75 mM $NO_3{^-}$), normal (2.5 mM $NO_3{^-}$) and excessive (5.0 and 10.0 mM $NO_3{^-}$). All samples, leaves, roots and xylem sap, were collected after 7 and 14 days after treatment. The levels of amino acids, soluble sugars and organic acids were significantly decreased by N-deficiency whereas, interestingly, they remained higher in xylem sap as compared with N-normal and -surplus. The N-excessive condition did not exert any significant changes in metabolites composition, and thus their levels were similar with N-normal. The gene expression and enzyme activity of nitrate reductase (NR), nitrite reductase (NIR) and glutamine synthetase (GS) were greatly influenced by nitrate. The data presented here suggest that metabolites, as a signal messenger, existed in xylem sap seem to play a crucial role to acquire nitrate, and, in addition, an increase in ${\alpha}$-ketoglutarate pathway-derived amino acids under N-deficiency may help to better understand plant C/N metabolism.

• 대한지역사회영양학회지
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• 제17권3호
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• pp.312-320
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• 2012

The purpose of this study was to investigate the perception of the school dietitian on superior agricultural products (SAP) and the status of using superior agricultural products in school meals. Questionnaires were distributed to 185 school dietitians after face to face interview, and a total of 181 responses were used for analysis. 82.3% of the respondents were using SAPs in school meals and there was a significant difference between elementary school (95.1%), middle school (76.8%) and high school (66.7%) dietitians (p < 0.001). 85.2% of the dietitians, who were using SAP, were purchasing SAPs through electronic bidding, and the main reason of not using SAPs was the higher price of SAPs than that of general agricultural products. The good agricultural practices (GAP) product was considered the most appropriate agricultural products for school meals by the majority of respondents (66.9%), and organic products was the next (13.3%). In addition, the most important selection criterion for a SAP perceived by school dietitians was safety (58.0%), and the main reason of using SAPs in school meals, when two choices were allowed, was 'to provide healthful food to children' (98.9%). The major barriers to using SAPs in school meals (two choices were allowed) were 'too expensive' (73.5%) and 'unstable supply' (32.6). In conclusion, it was suggested that there should be an improvement in SAP supply and management systems to increase the use of SAPs in school meals.

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1216-1225
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• 2014

Biofilm-related infections of Candida albicans are a frequent cause of morbidity and mortality in hospitalized patients, especially those with immunocompromised status. Options of the antifungal drugs available for successful treatment of drug-resistant biofilms are very few, and as such, new strategies need to be explored against them. The aim of this study was to evaluate the efficacy of phenylpropanoids of plant origin against planktonic cells, important virulence factors, and biofilm forms of C. albicans. Standard susceptibility testing protocol was used to evaluate the activities of 13 phenylpropanoids against planktonic growth. Their effects on adhesion and yeast-to-hyphae morphogenesis were studied in microplate-based methodologies. An in vitro biofilm model analyzed the phenylpropanoid-mediated prevention of biofilm development and mature biofilms using XTT-metabolic assay, crystal violet assay, and light microscopy. Six molecules exhibited fungistatic activity at ${\leq}0.5mg/ml$, of which four were fungicidal at low concentrations. Seven phenylpropanoids inhibited yeast-to-hyphae transition at low concentrations (0.031-0.5 mg/ml), whereas adhesion to the solid substrate was prevented in the range of 0.5-2 mg/ml. Treatment with ${\leq}0.5mg/ml$ concentrations of at least six small molecules resulted in significant (p < 0.05) inhibition of biofilm formation by C. albicans. Mature biofilms that are highly resistant to antifungal drugs were susceptible to low concentrations of 4 of the 13 molecules. This study revealed phenylpropanoids of plant origin as promising candidates to devise preventive strategies against drug-resistant biofilms of C. albicans.

• KSBB Journal
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• 제32권2호
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• pp.117-123
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• 2017

Maple tree is a useful medical plant for obtaining bioactive materials such as pharmaceutics, cosmetics, food additive, etc., and there are 16 species of native maple trees in Korea. In this study, we evaluated the antioxidant activity of sap and crude extracts of Acer mono Max, a representative maple species. The crude extracts were obtained by solvent extraction (water, ethanol, and ethyl acetate) from its branches (bark and xylem). The phenolic contents and radical scavenging capacities of the extracts and the sap were evaluated in terms of half maximal effective concentration ($EC_{50}$) and kinetics by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The ethanol extracts showed the highest extraction yield, phenolic contents and antioxidant activity, and bark extracts showed better antioxidant activity than xylem extracts. The antioxidant activity of the sap was very low, but the $EC_{50}$ of ethanol and ethyl acetate extracts ranged from 68 to $79{\mu}g/mL$, similar to that ($60{\mu}g/mL$) of the control, butylated hydroxytoluene (BHT). The DPPH radical scavenging rate ($220{\sim}760{\mu}M/min$) and the second-order reaction rate constant ($6.48{\sim}7.04L/g{\cdot}min$) of these extracts were better than those of BHT ($55{\sim}370{\mu}M/min$ and $3.60L/g{\cdot}min$). These results suggest that A. mono Max. is one of the useful bioresources for obtaining antioxidant biologically active substances, and it is possible to obtain physiologically active substances from by-product of its pruning while minimizing the effect on the growth of the tree.

• 공업화학
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• 제7권1호
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• pp.136-144
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• 1996

역상현탁 중합방법으로 sodium acrylate 및 아크릴산을 모노머로 사용하고 분산제로는 sucrose fatty acid ester(S-570), 증점제로는 Xanthan-gum, 가교제로는 EDGMA 및 GPGE, 개시제로는 $K_2S_2O_8$, 및 용매로는 사이클로헥산을 사용하여, sorbitol의 함유량을 10~50%로 변화시키면서 sorbitol이 결합하고 있는 고흡수성 수지(SAP)를 합성하였다. 합성한 고흡수성 수지를 모노머량의 0.05~0.40mol%로 표면가교 시켰고, 입자형태는 구형이었으며 입자크기 분포는 $177{\sim}707{\mu}m$ 이었다. 고흡수성 수지의 흡수량은 물에 대하여는 785~1086배 이었고, 0.9% NaCl 용액에 대해서는 50~83배 이었다. Sorbitol의 함유랑이 증가할 수록 고흡수성 수지의 흡수량과 보수량은 감소하였으며, +5 cal/g SAP의 흡열특성을 나타내었다.

• Steel and Composite Structures
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• 제34권6호
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• pp.853-862
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• 2020

In recent years, due to the many advantages cable-stayed bridges have often constructed in medium and long span. These advantages can be listed as an aesthetically pleasing appearance, economic and easy construction, etc. The main structural elements of cable-stayed bridges are listed as deck, pylon, cables and foundation. Perhaps one of the most vital and expensive of these structural elements is stay-cables. Stay-cables ensure the allowable displacement and distribution of bending moments along the bridge deck with prestressing force. Therefore the optimum design of the stay-cables and prestressing force are very important in achieving the performance expected from the cable-stayed bridges. This paper aims to obtain the stay-cables size and prestressing force optimization of the cable-stayed bridge. For this purpose, single pylon and fan type cable configuration Manavgat Cable-Stayed Bridge was selected as an example. The three dimensional (3D) finite element model (FEM) of the bridge was created with SAP2000. Analysis of the 3D FEM of the bridge was conducted under the different combined effects of the self-weight of the structural element, prestressing force of stay-cable and live load. Stay-cable stress and deck displacement were taken into account as constraints for the optimization problem. To optimize this existing bridge a metaheuristic algorithm named Jaya was used in the optimization process. 3D FEM of the selected bridge was repeatedly analyzed by using Open Applicable Programming Interface (OAPI) properties of SAP2000. To carry out the optimization process the developed program which integrates the Jaya algorithm and the required codes for calling SAP2000 is coded in MATLAB. At the end of the study, the total weight of the stay-cables was reduced more than 40% according to existing stay cables under loads taken into account.