• Title/Summary/Keyword: Aqueous

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The Effect of Molecular Weight on the Gelation Behavior of Regenerated Silk Solutions

  • Cho, Hee-Jung;Um, In-Chul
    • International Journal of Industrial Entomology and Biomaterials
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    • v.23 no.1
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    • pp.183-186
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    • 2011
  • The various molecular weight (MW) regenerated silk fibroins were prepared with different dissolution condition and the effect of MW on the gelation behavior of regenerated aqueous silk fibroin (SF) solution was investigated. The result of gelation time measurement indicated that the gelation of SF aqueous solution was accelerated by the increase of MW and SF concentration. When formic acid was added in SF aqueous solution, the gelation time of SFL and SFC30 aqueous solution showed a significant decreaseat 0.03% formic acid addition. In case of the lowest MW sample, SFC180, SF molecules became aggregated and precipitated without gelation after 28 days storage time. These findings indicate that MW control of SF can be utilized to control the gelation time of SF aqueous solution.

Screening of the Positive Inotropic Activity of Medicinal Plants Used in Oriental Medicine

  • Choi, Deok-Ho;Kang, Dae-Gil;Kim, Seung-Ju;Cui, Xun;Lee, Ho-Sub
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.20 no.3
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    • pp.730-734
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    • 2006
  • Aqueous extracts of medicinal plants traditionally used in the East Asia such as China, Korea, and Japan were screened for inotropic activity using isolated rabbit atria. Among the twenty-one aqueous-extracts from medicinal plants, the aqueous extracts of Convallaria keiskei(ACK) and rhizome of Coptis chinesis (ACC) were found to exhibit distinctive positive inotropic activity. The aqueous extracts of C. keiskei and rhizome of C. chinensis significantly increased atrial stroke volume and pulse pressure in beating rabbit atria. These findings suggest that the aqueous extracts of C. keiskei and rhizome of C. chinensis enhance the cardiac muscle contractility and then could be useful for the treatment of cardiac failure.

The Effect of Urea on Volumetric and Viscometric Properties of Aqueous Solutions of Poly(ethylene oxide)

  • 전상일;백경구
    • Bulletin of the Korean Chemical Society
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    • v.19 no.11
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    • pp.1194-1198
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    • 1998
  • The density and the viscosity of aqueous PEO solutions are observed with the several concentrations of PEO at 20 ℃. The effects of urea on them are also observed. The apparent and the partial specific volumes of PEO are calculated from the density data, which result that the polymer-polymer interaction is dominating in the binary aqueous PEO solutions, while the polymer-solvent interaction is dominating in the ternary aqueous urea-PEO solutions. It is explained by the urea induced breakage of the structured water originated from the hydrophobic interactions and the binding of the urea to the PEO chain. The concentration dependence of relative viscosity and the density dependence of fluidity is also discussed with the concept of the polymersolvent and the polymer-polymer interactions of aqueous urea-PEO solutions.

Evaluation of Early Strength of Red Clay Soil with Polymer Aqueous Solution (폴리머수용액을 첨가한 황토의 초기강도 평가)

  • Kim, Jin-Sung;Lee, Bo-Kyeong;Lee, Dong-Eun;Choi, Hyeong-Gil
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.145-146
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    • 2019
  • In this study, we evaluated the early strength of red clay soil with the polymer aqueous solution at rammed earth construction. In order to satisfy the demolding strength of the formwork be due to the rammed of red clay soil, the polymer aqueous solution was added to evaluate the compressive strength at the early age according to the consolidation level. As a result, a high compressive strength was exhibited with the formulation to which the polymer aqueous solution was added.

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Drop formation at submerged nozzles: Comparison of aqueous dispersed and organic dispersed cases for TBP-dodecane and nitric acid system

  • Roy, Amitava;Darekar, Mayur;Singh, K.K.;Shenoy, K.T.
    • Nuclear Engineering and Technology
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    • v.51 no.3
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    • pp.761-768
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    • 2019
  • Understanding the phenomena of formation of single drops is necessary to understand the hydrodynamics in solvent extraction equipment which are used for separation of nuclear materials. In this work, the phenomena of aqueous phase and organic phase drop formation at submerged nozzles are compared by conducting experiments with 30%TBP (v/v) in dodecane as the organic phase and nitric acid as the aqueous phase. Two different nozzles and three different nitric acid concentrations are used. For each nozzle and nitric acid concentration, velocity of the dispersed phase is varied. Drops of aqueous phase formed at downward oriented nozzles submerged in organic phase are observed to be smaller than the drops of organic phase formed at upward oriented nozzles submerged in aqueous phase. Correlations to estimate drop diameter are proposed.

Survival of Escherichia coli O157:H7 and Salmonella typhimurium Inoculated on Chicken by Aqueous Chlorine Dioxide Treatment

  • Hong, Yun-Hee;Ku, Kyoung-Ju;Kim, Min-Ki;Won, Mi-Sun;Chung, Kyung-Sook;Song, Kyung-Bin
    • Journal of Microbiology and Biotechnology
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    • v.18 no.4
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    • pp.742-745
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    • 2008
  • Inactivation of Escherichia coli O157:H7 and Salmonella typhimurium was evaluated on inoculated chicken by aqueous chlorine dioxide ($CIO_2$) treatment. Chicken samples were inoculated with 6-7 log CFU/g of Escherichia coli O157:H7 and Salmonella typhimurium, respectively. The chicken samples were then treated with 0, 50, and 100 ppm of $CIO_2$ solution and stored at $4{\pm}1^{\circ}C$. Aqueous $CIO_2$ treatment decreased the populations of the pathogenic bacteria on the chicken breast and drumstick. In particular, 100 ppm $CIO_2$ treatment on the chicken breast and drumstick reduced Escherichia coli O157:H7 and Salmonella typhimurium by 1.00-1.27 and 1.37-1.44 log CFU/g, respectively. Aqueous $CIO_2$ treatment on the growth of the bacteria was continuously in effect during storage, resulting in the decrease of the populations of Escherichia coli O157:H7 and Salmonella typhimurium. These results suggest that aqueous $CIO_2$ treatment should be useful in improving the microbial safety of chicken during storage.

Heat and Mass Transfer Characteristics of LiCl Aqueous Solution for a Plate Heat Exchanger Type Dehumidifier (판형 열교환기식 제습기에서 LiCl 수용액의 열 및 물질전달 특성)

  • Jeon, Dong-Soon;Lee, Hae-Seung;Kim, Seon-Chang;Kim, Young-Lyoul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.1
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    • pp.16-22
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    • 2012
  • Experimental investigations were carried out to examine the heat and mass transfer characteristics of LiCl aqueous solution for a plate heat exchanger type dehumidifier. Cooling dehumidification was adopted vertical type heat exchanger. Also non woven fabric is attached surface of the heat exchanger for spreadability of LiCl aqueous solution. Mass flow-rate of LiCl aqueous solution and concentration were selected as experimental conditions. Also, In this study, the effects of relative humidity of process air and velocity were investigated experimentally. As a result of heat transfer coefficient and mass transfer coefficient of were increased film reynolds number increased. heat transfer coefficient and mass transfer coefficient of LiCl aqueous solution were 0.14~0.24 kW/$m2^{\circ}C$ and $1.3{\times}10-63{\sim}6.2{\times}10-6$ m/s respectively.

Fermentation Characteristics and anti-Helicobacter pylori Activity of Aqueous Broccoli Fermented by Lactobacillus plantarum MG208

  • Yang, Ji-Won;Kim, Kyung Tack;Kim, Sung Soo
    • Journal of Applied Biological Chemistry
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    • v.58 no.1
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    • pp.89-95
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    • 2015
  • Helicobacter pylori infection causes gastrointestinal diseases such as chronic gastritis, peptic ulcers, and may lead to gastric cancer. Several studies have reported that lactobacilli present on broccoli show inhibitory activity against H. pylori. Here, we evaluated aqueous broccoli, fermented by Lactobacillus plantarum MG208, for its fermentation characteristics and anti-H. pylori activities including antibacterial activity, growth inhibition, anti-adhesion, and urease inhibition. The results indicated that the fermentation characteristics changed significantly depending on the amount of aqueous broccoli used for fermentation (p <0.05). There was no significant difference between the samples before fermentation (p >0.05). However, a significant concentration-dependent difference was noted in antibacterial activity and urease inhibition (p <0.05) following the addition of aqueous broccoli. Growth inhibition in the 10 mg/mL sample was significantly higher as compared to the negative control and similar to that with amoxicillin (positive control) (p <0.05). Anti-adhesion activity of aqueous broccoli was also significantly different (p <0.05) from the negative control. Therefore, aqueous broccoli fermented by L. plantarum MG208 could prove useful as a functional diet for protection of the gastric environment against H. pylori infection.

Inactivation of Agrobacterium tumefaciens Inoculated on Fresh Radix Ginseng by Electron Beam Irradiation and Aqueous Chlorine Dioxide Treatment

  • Chun, Ho-Hyun;Kim, Ju-Yeon;Song, Kyung-Bin
    • Journal of Applied Biological Chemistry
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    • v.51 no.3
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    • pp.117-122
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    • 2008
  • Inactivation of Agrobacterium tumefaciens was evaluated on the inoculated fresh Radix Ginseng by electron beam irradiation or aqueous chlorine dioxide ($ClO_2$) treatment. Two groups of fresh ginsengs were prepared and inoculated with A. tumefaciens. One group was then irradiated at 0, 2, and 4 kGy using an electron beam accelerator, and the other group was treated with 0, 50, and 100 ppm of aqueous $ClO_2$. Microbiological data indicated that populations of A. tumefaciens significantly decreased with increasing irradiation dose or aqueous $ClO_2$ concentration. In particular, A. tumefaciens was eliminated by irradiation at 4 kGy, and 100 ppm $ClO_2$ treatment reduced the populations of A. tumefaciens by 1.44 log CFU/g. These results suggest that electron beam irradiation or aqueous $ClO_2$ treatment can be useful in improving the microbial safety of fresh ginsengs during storage.

A Study on Oxidation Characteristics and Phytoncide Oil Decomposition Characteristics of Aqueous Solution by 400 kHz Medium Frequency Ultrasound (400 kHz 중주파 초음파에 의한 수용액의 산화특성 및 피톤치드 오일 분해특성에 대한 연구)

  • Hwangbo, Sunae;Kim, Buan;Moon, Changkwan
    • Particle and aerosol research
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    • v.13 no.3
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    • pp.127-132
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    • 2017
  • In this paper, the effect of the irradiation of the median-frequency of ultrasonic wave on the aqueous solution have been investigated. In addition, the decomposition ability of radical species was observed using phytoncide oil of 0.1 wt %. By observing the degree of decomposition while maintaining magnetic stirring, the unirradiated aqueous solution maintained turbid condition and the particle size of the oil was the same as the initial size. On the other hand, the irradiated aqueous solution presented that the transparency degree became good after 3 days and became to the same as the original purified water after one week. The particle size of the after 3 days was about 0.1 to $0.5{\mu}m$. From these results it could be demonstrated that when a medium frequency (about 400 kHz) is applied to the aqueous solution, decomposition ability of radical species are formed and the medium frequency irradiation system can be possible to purify the turbid aqueous solution.