• Title/Summary/Keyword: Water reducing agent

Search Result 267, Processing Time 0.03 seconds

Anti-melanogenic effects of Hordeum vulgare L. barely sprout extract in murine B16F10 melanoma cells

  • Choi, Jeong-Hwa;Jung, Jong-Gi;Kim, Jung-Eun;Bang, Mi-Ae
    • Journal of Nutrition and Health
    • /
    • v.52 no.2
    • /
    • pp.168-175
    • /
    • 2019
  • Purpose: Barely sprout is a well-known oriental herbal medicine with a wide range of health benefits. Recent studies have provided scientific evidence of its therapeutic effects with expanded application. This study investigated anti-melanogenic effect of barley sprout water extract (BSE) in murine melanocyte B16F10. Methods: Various concentrations (0, 50, 125, and $250{\mu}g/mL$) of BSE and arbutin (150 ppm) were applied to B16F10 stimulated with or without alpha-melanocyte stimulating hormone (100 nM) for 72 hours. The whitening potency of BSE was determined altered cellular melanin contents. Activity and expression of tyrosinase and microphthalmia-associated transcription factor (MITF) were also assayed. Results: Experimental results revealed that treatment with BSE reduced cellular melanin production by approximately 40% compared to the control. Molecular findings supported that suppressed activity and expression of tyrosinase and MITF proteins by BSE were associated with declined cellular melanogenesis. Furthermore, anti-melanogenic effect of BSE ($250{\mu}g/mL$) was similar to that of arbutin, a commonly used whitening agent. Lastly, polyphenols including p-coumaric, ferulic, and vanillic acids were identified in BSE using HPLC analyses. They might be potential active ingredients showing such melanogenesis-reducing effect. Conclusion: BSE was evident to possess favorable anti-melanogenic potency in an in vitro model. As a natural food sourced material, BSE could be an effective depigmentation agent with potential application in pharmaceutical and cosmetic industries.

Engineering Properties of the Concrete Using Reject Ash as Pre-mixed Fine Aggregate (리젝트애시를 잔골재로 프리믹스하여 활용하는 콘크리트의 공학적 특성)

  • Han, Min-Cheol;Hyun, Seung-Yong
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.7 no.1
    • /
    • pp.44-49
    • /
    • 2019
  • The purpose of this study is to analyze the fundamental characteristics of concrete with the change of reject ash(Reject ash=Rj) in the mixed aggregate where single grain aggregate of different grain size and aggregate of opposite grain size are mixed together, to analyze the possibility of a mixed aggregate system that premixes at an aggregate manufacturing plant and delivers it as one aggregate. As a result of the experimental study, it was found that the grain size regulation is satisfied if the mixed aggregate(CSb+SS) is substituted for about 5% of Rj. In the case of the fluidity slump, slump flow and air volume, it was found that they decrease as the substitution ratio of Rj increases, while the compressive strength increases as the substitution ratio of Rj increases. Therefore, it is analyzed that it would contribute greatly to an improvement of quality such as improvement of compressive strength if adequate fluidity and air quantity are secured by the water reducing agent and AE agent while premixing the Rj, which is disposed of by landfill, with about 5% of the mixed aggregate.

The Electrochemical Characteristics of MEA with Pt/Cross-Linked SPEEK-HPA Composite Membranes/Pt-Ru for Water Electrolysis (수전해용 Pt/공유가교 SPEEK-HPA 복합막/Pt-Ru MEA의 전기화학적 특성)

  • Hwang, Yong-Koo;Woo, Je-Young;Lee, Kwang-Mun;Chung, Jang-Hoon;Moon, Sang-Bong;Kang, An-Soo
    • Journal of Hydrogen and New Energy
    • /
    • v.20 no.3
    • /
    • pp.194-201
    • /
    • 2009
  • The e1ectrocatalytic properties of heteropolyacids(HPAs) entrapped in covalently cross-linked sulfonated polyetheretherketone(CL-SPEEK/HPA) membranes have been studied for water electrolysis. The HPAs, including tungstophosphoric acid(TPA), molybdophosphoric acid(MoPA), and tungstosilicic acid(TSiA) were used as additives in the composite membranes. The MEA was prepared by a non-equilibrium impregnation-reduction(I-R) method, using reducing agent, sodium borohydride(NaBH4) and tetraamineplatinum(II) chloride(pt(NH$_3$)$_4$Cl$_2$). The electrocatalytic properties of composite membranes such as the cell voltage were in the order of magnitude CL-SPEEKlMoPA40 (wt%) > /TPA30 > /TSiA40. In the optimum cell applications for water electrolysis, the cell voltage of PtlPEM/Pt-Ru MEA with CL-SPEEKlTPA30 membrane was 1.75 V at 80$^{\circ}$C and I A/cm$^2$ and this voltage carried lower than that of 1.81 V of Nafion 117. Consequently, in regards of electrochemical and mechanical characteristics and oxidation durability, the newly developed CL-SPEEKITPA30 composite membrane exhibited a better performance than the others, but CLSPEEKlMoPA40 showed the best electrocatalytic activity (1.71 Vat 80$^{\circ}$C and 1 A/cm$^2$) among the composite membranes.

Moisture Absorption Characteristics of Pt/Nafion Membrane for PEMFC Prepared by a Drying Process (건식법에 의해 제조한 PEMFC용 Pt/나피온 막의 흡습 특성)

  • Lee, Jae-Young;Lee, Hong-Ki
    • Journal of Hydrogen and New Energy
    • /
    • v.23 no.4
    • /
    • pp.310-315
    • /
    • 2012
  • A simple drying process was developed for the preparation of a Pt/Nafion self-humidifying membrane to be used for a proton-exchange membrane fuel cell (PEMFC). Platinum (II) bis (acetylacetonate), $Pt(acac)_2$ was sublimed, penetrated into the surface of a Nafion film and then reduced to Pt nanoparticles simultaneously without any support of a reducing agent in a glass reactor at $180^{\circ}C$ for 15 min. The process was carried out in $N_2$ atmosphere to prevent the oxidation of Pt nanoparticles at high temperature. The morphology and distribution of the Pt nanoparticles were observed by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS), and we found that the average Pt particle size was ca. 3.7 nm, the penetration depth was ca. $17{\mu}m$. Almost all Pt nanoparticles were formed just beneath the surface and the number density decreased rapidly as the penetration depth increased. To estimate water absorption characteristics of the Nafion membranes, water uptake at an isothermal condition was measured by dynamic vapor sorption (DVS), and it was found that water uptake of the Pt/Nafion membrane was higher than that of the neat Nafion membrane.

A Study on the Factors Affecting the High Fluid Mortar Containing Ground Granulated Blast-furnace Slag (고로슬래그 미분말을 함유한 고유동 모르터의 유동성상에 미치는 영향 요인에 관한 연구)

  • Kim, Jae-Hun;Yoon, Sang-Chun;Jee, Nam-Yong
    • Journal of the Korea Institute of Building Construction
    • /
    • v.2 no.4
    • /
    • pp.145-152
    • /
    • 2002
  • High fluid concrete unlike OPC concrete is made with various material, and the phase of fresh concrete is considerably different. In order to understand fluidity phase and mix properties of high fluid concrete, concrete is required to access as suspension structure which consists of aggregate and paste. The focus of this paper is to analyze the test results and quantify the effect of mix proportions of mortar and fineness modulus of sand on the properties of fresh mortar. The effect of water-binder ratio. sand-binder ration. contents of ggbs (by mass of total cementitious materials). and various contents of water reducing agent on the yield stress and plastic viscosity of the mix is studied. Based on the experimental results, the fellowing conclusions can be drawn: (1) The mixing time needed for high fluid mortar was approximately two times more than that of ordinary portland mortar. (2) The fluidity phase of mortar could be explained by yield stress of mix and the fluidity of mortar. (3) As the content of ggbs increased, yield stress of mortar was decreased and plastic viscosity of it was increased. (4) For the high fluid mortar, it was appeared that sand-binder ratio should be below 1.5.

Antioxidant Activity, Macamide B Content and Muscle Cell Protection of Maca (Lepidium meyenii) Extracted Using Ultrasonification-Assisted Extraction

  • Buyanbadrakh, Enkhbolor;Hong, Hyeong-Suk;Lee, Kang-Woo;Huang, Wen Yan;Oh, Jun-Hyun
    • Microbiology and Biotechnology Letters
    • /
    • v.48 no.2
    • /
    • pp.129-137
    • /
    • 2020
  • This study aims to evaluate the efficacy of the Ultrasonication-Assisted (UA) extraction on the functionality of the herbaceous biennial plant maca (Lepidium meyenii). The specific objectives include comparison of the antioxidant activities among various maca extracts, determination of the macamide B content of the extracts, and in vitro evaluation of maca on cell viability and creatine kinase (CK) activity. The antioxidant activities of the water, ethanol, and UA extracts were compared by determining the total phenolic and flavonoid contents, the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, and the ferric reducing antioxidant power (FRAP) of the extracts. The macamide B content of maca extracts were analyzed by HPLC. The effects of the extracts on muscle cell viability and creatine kinase activity were also determined using C2C12 myoblasts. UA extraction significantly increased the total phenolic content (2.90 GAE ㎍/mg, p < 0.05), without affecting the flavonoid content. DPPH radical scavenging activity did not exhibit any statistical difference among the extracts. The ethanol and UA extracts exhibited significantly higher FRAP than the water extract (p < 0.05). The macamide B content of ethanol and UA extracts were 0.087 and 0.083 ㎍/mg, respectively. The water and UA extracts exhibited higher C2C12 muscle cell viability than the ethanol extract, and both extracts resulted in a significantly lower CK level than the H2O2-treated control group. This research suggests that the maca extract can protect muscle cells and serve as an antifatigue agent under oxidative stress conditions.

Biosurfactant as a microbial pesticide

  • Lee, Baek-Seok;Choi, Sung-Won;Choi, Ki-Hyun;Lee, Jae-Ho;Kim, Eun-Ki
    • 한국생물공학회:학술대회논문집
    • /
    • 2003.04a
    • /
    • pp.40-44
    • /
    • 2003
  • Soil-borne infectious disease including Pythium aphanidermatum and Rhizoctonia solani causes severe damage to plants, such as cucumber. This soil-borne infectious disease was not controlled effectively by chemical pesticide. Since these diseases spread through the soil, chemical agents are usually ineffective. Instead, biological control, including antagonistic microbe can be used as a preferred control method. An efficient method was developed to select an antagonistic strain to be used as a biological control agent strain. In this new method, surface tension reduction potential of an isolate was included in the ‘decision factor’ in addition to the other factors, such as growth rate, and pathogen inhibition rate. Considering these 3 decision factors by a statistical method, an isolate from soil was selected and was identified as Bacillus sp. GB16. In the pot test, this strain showed the best performance among the isolated strains. The lowest disease incidence rate and fastest seed growth was observed when Bacillus sp. GB16 was used. Therefore this strain was considered as plant growth promoting rhizobacteria (PGPR). The action of surface tension reducing component was deduced as the enhancement of wetting, spreading, and residing of antagonistic strain in the rhizosphere. This result showed that new selection method was significantly effective in selecting the best antagonistic strain for biological control of soil-borne infectious plant pathogen. The antifungal substances against P. aphanidermatum and R. solani were partially purified from the culture filtrates of Bacillus sp. GB16. In this study, lipopeptide possessing antifungal activity was isolated from Bacillus sp. GB16 cultures by various purification procedures and was identified as a surfactin-like lipopeptide based on the Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), high performance liquid chromatography mass spectroscopy (HPLC-MS), and quadrupole time-of-flight (Q-TOF) ESI-MS/MS data. The lipopeptide, named GB16-BS, completely inhibited the growth of Pythium aphanidermatum, Rhizoctonia solani, Penicillium sp., and Botrytis cineria at concentrations of 10 and 50 mg/L, respectively. A novel method to prevent the foaming and to provide oxygen was developed. During the production of surface active agent, such as lipopeptide (surfactin), large amount of foam was produced by aeration. This resulted in the carryover of cells to the outside of the fermentor, which leads to the significant loss of cells. Instead of using cell-toxic antifoaming agents, low amount of hydrogen peroxide was added. Catalase produced by cells converted hydrogen peroxide into oxygen and water. Also addition of corn oil as an oxygen vector as well as antifoaming agent was attempted. In addition, Ca-stearate, a metal soap, was added to enhance the antifoam activity of com oil. These methods could prevent the foaming significantly and maintained high dissolved oxygen in spite of lower aeration and agitation. Using these methods, high cell density, could be achieved with increased lipopeptide productivity. In conclusion to produce an effective biological control agent for soil-borne infectious disease, following strategies were attempted i) effective screening of antagonist by including surface tension as an important decision factor ii) identification of antifungal compound produced from the isolated strain iii) novel oxygenation by $H_2O_2-catalase$ with vegetable oil for antifungal lipopeptide production.

  • PDF

Oxidative Degradation of Phenol Using Zero-Valent Iron-Based Fenton-Like Systems (영가철 기반 펜톤 시스템을 활용한 페놀의 산화분해)

  • Kim, Hak-Hyeon;Lee, Hye-Jin;Kim, Hyung-Eun;Lee, Hongshin;Lee, Byeong-Dae;Lee, Changha
    • Journal of Soil and Groundwater Environment
    • /
    • v.18 no.4
    • /
    • pp.50-57
    • /
    • 2013
  • For the last couple of decades, the Fenton (-like) systems have been extensively studied for oxidation of organic contaminants in water. Recently, zero-valent iron (ZVI) has received attention as a Fenton catalyst as well as a reducing agent capable of producing reactive oxidants from oxygen. In this study, the ZVI-based Fenton reaction was assessed for the oxidative degradation of phenol using $ZVI/O_2$, $ZVI/H_2O_2$, ZVI/Oxalate/$O_2$ and hv/ZVI/Oxalate/$O_2$ systems. Reaction parameters such as pH and reagent dose (e.g., ZVI, $H_2O_2$, and oxalate) were examined. In the presence of oxalate (ZVI/Oxalate/$O_2$ and hv/ZVI/Oxalate/$O_2$ systems), the degradation of phenol was greatly enhanced at neutral pH values. It was found that ZVI accelerates the Fenton reaction by reducing Fe(III) into Fe(II). The conversion of Fe(III) into Fe(II) by ZVI was more stimulated at acidic pH than at near-neutral pH values.

Shrinkage Reduction Performance of HPFRCC Using Expansive and Srhinkage Reducing Admixtures (팽창재와 수축저감제를 사용한 HPFRCC의 수축 저감 성능)

  • Park, Jung-Jun;Moon, Jae-Heum;Park, Jun-Hyoung;Lee, Jang-Hwa;Kim, Sung-Wook
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.18 no.5
    • /
    • pp.34-40
    • /
    • 2014
  • High-performance fiber-reinforced cement composite (HPFRCC) shows very high autogenous shrinkage, because it contains a low water-to-binder ratio (W/B) of 0.2 and high fineness admixture without coarse aggregate. Thus, it needs a method to decrease the cracking potential. Accordingly, in this study, to effectively reduce the shrinkage of HPFRCC, a total of five different ratios of SRA (1% and 2%), EA (5% and 7.5%), and a combination of SRA and EA (1% and 7.5%) were considered. According to the test results of ring-test, a combination of SRA and EA (1% and 7.5%) showed best performance regarding restrained shrinkage behavior without significant deterioration of compressive and tensile strengths. This was also verified by performing modified drying shrinkage crack test.

Technology on the Shrinkage Reduction of High Performance Concrete (고성능 콘크리트의 수축 저감 기술)

  • Koh, Kyung-Taek;Ryu, Gum-Sung;Kang, Su-Tae;Park, Jung-Jun;Kim, Sung-Wook;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.04a
    • /
    • pp.1101-1104
    • /
    • 2008
  • Recently, active researches are conducted on high performance concrete(HPC) exhibiting high strength and high fluidity. These researches are resulting in increased applications on real structures. In order to satisfy the required performances, HPC makes use of large quantities of binder and presents low water-cementitious material ratio. Such mixing is increasing significantly the autogenous shrinkage, which subsequently is likely to favor the potential development of cracks. Therefore, we investigated the effect of used materials and mix proportions on the shrinkage properties of HPC, and of the use of expansive additives and shrinkage reducing agents on the HPC. The autogenous shrinkage of HPC using blast furnace slag are tend to be increased, in some case have the potential development of cracks by only the autogenous shrinkage. Also the using method in combination with expansive additive and shrinkage reducing agent is more effective than the separately using method of that.

  • PDF