• 제목/요약/키워드: Active chemical

검색결과 2,278건 처리시간 0.026초

Using response surface methodology and Box-Behnken design in the study of affecting factors on the dairy wastewater treatment by MEUF

  • Khosroyar, Susan;Arastehnodeh, Ali
    • Membrane and Water Treatment
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    • 제9권5호
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    • pp.335-342
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    • 2018
  • Micelle-Enhanced Ultrafiltration (MEUF) is a membrane separation processes that improving ultrafiltration process with the formation of micelles of the surface active agents. Surface active agents are widely used to improve membrane processes due to the ability to trap organic compounds and metals in the treatment of industrial waste water. In this study, surface active agents are used to improve micelle-enhanced ultrafiltration (MEUF) to reduce chemical oxygen demand (COD), total dissolved solid (TDS), turbidity and clogging the membrane in dairy wastewater treatment. Three important operational factors (anionic surface active agent concentration, pressure and pH) and these interactions were investigated by using response surface methodology (RSM) and Box-Behnken design. Results show that due to the concentration polarization layer and increase the number of Micelles; the anionic surface active agent concentration has a negative effect on the flux and has a positive effect on the elimination of contamination indices. pH, and the pressure have the greatest effect on flux. On the other hand, it could be stated that these percentages of separation are in the percentages range of Nano-filtration (NF). While MEUF process has higher flux than NF process. The results have been achieved at lower pressure while NF process needs high pressure, thus making MEUF is the replacement for the NF process.

Copper micro/nanostructures as effective SERS active substrates for pathogen detection

  • Ankamwar, Balaprasad;Sur, Ujjal Kumar
    • Advances in nano research
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    • 제9권2호
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    • pp.113-122
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    • 2020
  • Surface-Enhanced Raman Scattering (SERS) spectroscopy is a multifaceted surface sensitive methodology which exploits spectroscopy-based analysis for various applications. This technique is based on the massive amplification of Raman signals which were feeble previously in order to use them for appropriate identification at qualitative and quantitative in chemical as well as biological systems. This novel powerful technique can be utilized to identify pathogens such as bacteria and viruses. As far as SERS is concerned, one of the most studied problems has been functionalization of SERS active substrate. Metal colloids and nanostructures or microstructures synthesized using noble metals such as Au, Ag and Cu are considered to be SERS active. Silver and gold are extensively used as SERS active substrates due to chemical inertness and stability in air compare to copper. However, use of Cu as a suitable alternative has been taken into account as it is cheap. Herein, we have synthesized air-stable copper microstructures/nanostructures by chemical, electrochemical and microwave-assisted methods. In this paper, we have also discussed the use of as synthesized copper micro/nanostructures as inexpensive yet effective SERS active substrates for the fast identification of micro-organisms like Staphylococcus aureus and Escherichia coli.

The Dual-frequency (20/40 kHz) Ultrasound Assisted Photocatalysis with the Active Carbon Fiber-loaded Fe3+-TiO2 as Photocatalyst for Degradation of Organic Dye

  • Xiong, Shaofeng;Yin, Zhoulan;Zhou, Yuanjin;Peng, Xianzhong;Yan, Wenbin;Liu, Zhixiong;Zhang, Xiangyu
    • Bulletin of the Korean Chemical Society
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    • 제34권10호
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    • pp.3039-3045
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    • 2013
  • Dual-frequency ultrasound assisted photocatalysis (DUAP) method was proposed to degrade a stable organic model effluent, cresol red (CR), using the prepared $Fe^{3+}$-doped $TiO_2$ with active carbon fiber loading ($Fe^{3+}-TiO_2/ACF$) as photocatalyst. The influence of key factors, including Fe doping amount and power density of dual-frequency ultrasounds (20/40 kHz), on the degradation efficiency was investigated. The degradation efficiency rises to 98.7% in 60 min accompanied by the color removal of CR liquid samples from yellow to colorless transparent at optimal conditions. A synergy index of 1.40 was yielded by comparison with single ultrasound assisted photocatalysis (SUAP) and the photocatalysis without ultrasound assisted (UV/$TiO_2$), indicating that a clear synergistic effect exists for the DUAP process. Obvious enhancement of degradation efficiency for the DUAP process should be attributed to production of large amount of free radicals by strong cavitational effects of dual ultrasounds.

Ginsentology II: Chemical Structure-Biological Activity Relationship of Ginsenoside

  • Lee, Byung-Hwan;Nah, Seung-Yeol
    • Journal of Ginseng Research
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    • 제31권2호
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    • pp.69-73
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    • 2007
  • Since chemical structures of ginsenoside as active ingredient of Panax ginseng are known, accumulating evidence have shown that ginsenoside is one of bio-active ligands through the diverse physiological and pharmacological evaluations. Chemical structures of ginsenoside could be divided into three parts depending on diol or triol ginsenoside: Steroid- or cholesterol-like backbone structure, carbohydrate portions, which are attached at the carbon-3, -6 or -20, and aliphatic side chain coupled to the backbone structure at the carbon-20. Ginsenosides also exist as stereoisomer at the carbon-20. Bioactive ligands usually exhibit the their structure-function relationships. In ginsenosides, there is little known about the relationship of chemical structure and biological activity. Recent reports have shown that ginsenoside $Rg_3$, one of active ginsenosides, exhibits its differential physiological or pharmacological actions depending on its chemical structure. This review will show how ginsenoside $Rg_3$, as a model compound, is functionally coupled to voltage-gated ion channel or ligand-gated ion channel regulations in related with its chemical structure.

성능향상을 위한 리튬전지의 Cathode active material에 관한 연구 (A Study on Cathode active material of Li/MnO$_2$ Battery for performance improvement)

  • 김학주;송수정
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2001년도 추계산학기술 심포지엄 및 학술대회 발표논문집
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    • pp.79-84
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    • 2001
  • 본 논문에서는 리튬전지의 Cathode active material로 CMD(chemical manganese dioxide)를 사용하여 현재 사용중인 EMD(electrolytic manganese dioxide)와 공정 수율 및 특성과 방전 성능을 비교함으로써 새로운 cathode active material.로의 적용 가능성을 확인하기 위함이다.

Biological Control Potential of Penicillium brasilianum against Fire Blight Disease

  • Kim, Yeong Seok;Ngo, Men Thi;Kim, Bomin;Han, Jae Woo;Song, Jaekyeong;Park, Myung Soo;Choi, Gyung Ja;Kim, Hun
    • The Plant Pathology Journal
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    • 제38권5호
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    • pp.461-471
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    • 2022
  • Erwinia amylovora is a causative pathogen of fire blight disease, affecting apple, pear, and other rosaceous plants. Currently, management of fire blight relies on cultural and chemical practices, whereas it has been known that few biological resources exhibit disease control efficacy against the fire blight. In the current study, we found that an SFC20201208-M01 fungal isolate exhibits antibacterial activity against E. amylovora TS3128, and the isolate was identified as a Penicillium brasilianum based on the 𝛽-tubulin (BenA) gene sequence. To identify active compounds from the P. brasilianum culture, the culture filtrate was partitioned with ethyl acetate and n-butanol sequentially. From the ethyl acetate layer, we identified two new compounds (compounds 3-4) and two known compounds (compounds 1-2) based on spectroscopic analyses and comparison with literature data. Of these active compounds, penicillic acid (1) exhibited promising antibacterial activity against E. amylovora TS3128 with a minimal inhibitory concentration value of 25 ㎍/ml. When culture filtrate and penicillic acid (125 ㎍/ml) were applied onto Chinese pearleaf crab apple seedlings prior to inoculation of E. amylovora TS3128, the development of fire blight disease was effectively suppressed in the treated plants. Our results provide new insight into the biocontrol potential of P. brasilianum SFC20201208-M01 with an active ingredient to control fire blight.

DNA Ligand - Redox Active Molecule Conjugates as an Electrochemical DNA Probe

  • Ihara, Toshihiro;Maruo, Voshiyuki;Uto, Yoshihiro;Takenaka, Shigeori;Takagi, Makoto
    • 분석과학
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    • 제8권4호
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    • pp.887-894
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    • 1995
  • Toward the development of universal, sensitive, and convenient method of DNA (or RNA) detection, two kinds of electrochemically active DNA ligands. acridine - viologen and oligonucleotide - ferrocene conjugate, were prepared. Thermodynamic and electrochemical study revealed that these probes bound strongly to DNA, and showed a typical cyclic voltammograms, indicating a potential for use as a reversible electrochemical labelling agent for DNA. Especially, using the electrochemically active oligonucleotide, we have been able to demonstrate the detection of DNA at femtomole levels by HPLC equipped with ordinary electrochemical detector (ECD). These results lead to the conclusion that the redox-active probes are very useful for the microanalysis of nucleic acid due to the stabilily of the complexes, high detection sensitivity, and wide applicability to the target structures (single- and double strands) and sequences.

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