The Experts below are selected from a list of 4200 Experts worldwide ranked by ideXlab platform
Jincai Zhao - One of the best experts on this subject based on the ideXlab platform.
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photodegradation of <B>SulforhodamineB> B dye in platinized titania dispersions under visiBle light irradiation influence of platinum as a functional co catalyst
Journal of Physical Chemistry B, 2002Co-Authors: Wei Zhao, Chuncheng Chen, Xiangzhong Li, Jincai Zhao, Hisao Hidaka, Nick SerponeAbstract:The photooxidative degradation of <B>SulforhodamineB>-B dye (SRB) taking place in visiBle-light illuminated platinized titania dispersions is revisited to examine the influence of metallic platinum doped on TiO2 particles (Degussa P25 titania) By photocatalytic deposition from a hexachloroplatinic acid solution. The various TiO2/Pt specimens were characterized By transmission electron microscopy (TEM), UV−vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The self-photosensitized degradation of SRB mediated By TiO2/Pt specimens is 3-fold faster than that occurring on TiO2 alone under visiBle light irradiation and under otherwise identical conditions. That is, the TiO2/Pt system exhiBited greater catalytic activity than P25 TiO2 alone, which earlier proved to Be an effective photocatalyst in the degradation of dyes under visiBle illumination. A reaction mechanism is proposed on the Basis of a series of experiments that included spin−trap electron spin resonance (ESR) spectral resu...
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photodegradation of <B>SulforhodamineB> B dye in platinized titania dispersions under visiBle light irradiation influence of platinum as a functional co catalyst
Journal of Physical Chemistry B, 2002Co-Authors: Wei Zhao, Chuncheng Chen, Jincai Zhao, Hisao Hidaka, Nick SerponeAbstract:The photooxidative degradation of <B>SulforhodamineB>-B dye (SRB) taking place in visiBle-light illuminated platinized titania dispersions is revisited to examine the influence of metallic platinum dope...
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photooxidation pathway of <B>SulforhodamineB> B dependence on the adsorption mode on tio2 exposed to visiBle light radiation
Environmental Science & Technology, 2000Co-Authors: And Xiangzhong Li, Jincai Zhao, Hisao Hidaka, Nick SerponeAbstract:The temporal course of the photooxidation of <B>SulforhodamineB>-B (SRB) in aqueous media illuminated By visiBle wavelengths in the presence of TiO2 has Been examined to determine the nature of the intermediate species produced and to explore the operative reaction pathway(s). Two pathways are descriBed to account for the differences in the final photooxidation products whose nature depends on the different modes of adsorption of the dye on the metal-oxide mediator. In the SRB/TiO2 system, when SRB is adsorBed on the positively charged TiO2 particle surface through a sulfonate group cleavage of the SRB chromophore structure predominates and N-de-ethylation occurs only to a slight extent with the major photooxidation products Being diethylamine and carBon dioxide. In the presence of the anionic dodecylBenzenesulfonate surfactant DBS, when SRB is near the negatively charged DBS/TiO2 interface through the positive diethylamine group N-de-ethylation occurs preferentially Before destruction of the structure with th...
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esr spin trapping detection of radical intermediates in the tio2 assisted photo oxidation of <B>SulforhodamineB> B under visiBle irradiation
Journal of Photochemistry and Photobiology A-chemistry, 2000Co-Authors: Guangming Liu, Jincai Zhao, Hisao HidakaAbstract:ABstract The ESR spin-trapping technique using 5,5-dimethyl-1-pyrroline- N -oxide (DMPO) and N - t -Butyl-α-phenyl-nitrone (PBN) as spin-trap reagents has Been applied to detect free radical intermediates generated during the in situ visiBle irradiation of aqueous <B>SulforhodamineB> B (SRB)–TiO 2 air-saturated dispersion. Hydroxyl radical ( OH), hydroperoxyl radical (HO 2 ) and hydrated electrons (e aq − ) were detected in the TiO 2 -assisted photo-oxidation of SRB under visiBle irradiation. The mechanism for the generation of active oxygen radicals and the role of these photogenerated active oxygen radicals in the photo-oxidation process are discussed. It is suggested that the oxygen molecules rather than these active oxygen radicals are the main oxidizing agent and play an important role in the visiBle photo-oxidation of SRB mediated By TiO 2 particles.
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photocatalytic degradation of dye <B>SulforhodamineB> B a comparative study of photocatalysis with photosensitization
New Journal of Chemistry, 2000Co-Authors: Guangming Liu, Jincai ZhaoAbstract:The direct photocatalytic degradation of dye pollutant <B>SulforhodamineB> B (SRB) in aqueous TiO2 dispersions has Been examined and compared to the photosensitization process. The mineralization extent of SRB degradation, the formation of intermediates and final products were monitored to assess the degradation pathways caused By direct photocatalysis. In the initial stage of the direct photocatalysis, SRB is mainly oxidized By a positive hole upon Band-gap excitation of TiO2 By UV light (330 nm<λ<380 nm) and suBsequently undergoes the similar degradation pathways as occur in the photosensitization under visiBle irradiation (λ>420 nm). Diethylamine, N,N-diethylacetamide, N-ethylformamide, N,N-diethylformamide, formic acid and acetic acid were identified as intermediate species; SO42−, NH4+, CO2 and H2O are final mineralized products produced in the direct photocatalytic process.
Nick Serpone - One of the best experts on this subject based on the ideXlab platform.
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photodegradation of <B>SulforhodamineB> B dye in platinized titania dispersions under visiBle light irradiation influence of platinum as a functional co catalyst
Journal of Physical Chemistry B, 2002Co-Authors: Wei Zhao, Chuncheng Chen, Xiangzhong Li, Jincai Zhao, Hisao Hidaka, Nick SerponeAbstract:The photooxidative degradation of <B>SulforhodamineB>-B dye (SRB) taking place in visiBle-light illuminated platinized titania dispersions is revisited to examine the influence of metallic platinum doped on TiO2 particles (Degussa P25 titania) By photocatalytic deposition from a hexachloroplatinic acid solution. The various TiO2/Pt specimens were characterized By transmission electron microscopy (TEM), UV−vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The self-photosensitized degradation of SRB mediated By TiO2/Pt specimens is 3-fold faster than that occurring on TiO2 alone under visiBle light irradiation and under otherwise identical conditions. That is, the TiO2/Pt system exhiBited greater catalytic activity than P25 TiO2 alone, which earlier proved to Be an effective photocatalyst in the degradation of dyes under visiBle illumination. A reaction mechanism is proposed on the Basis of a series of experiments that included spin−trap electron spin resonance (ESR) spectral resu...
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photodegradation of <B>SulforhodamineB> B dye in platinized titania dispersions under visiBle light irradiation influence of platinum as a functional co catalyst
Journal of Physical Chemistry B, 2002Co-Authors: Wei Zhao, Chuncheng Chen, Jincai Zhao, Hisao Hidaka, Nick SerponeAbstract:The photooxidative degradation of <B>SulforhodamineB>-B dye (SRB) taking place in visiBle-light illuminated platinized titania dispersions is revisited to examine the influence of metallic platinum dope...
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photooxidation pathway of <B>SulforhodamineB> B dependence on the adsorption mode on tio2 exposed to visiBle light radiation
Environmental Science & Technology, 2000Co-Authors: And Xiangzhong Li, Jincai Zhao, Hisao Hidaka, Nick SerponeAbstract:The temporal course of the photooxidation of <B>SulforhodamineB>-B (SRB) in aqueous media illuminated By visiBle wavelengths in the presence of TiO2 has Been examined to determine the nature of the intermediate species produced and to explore the operative reaction pathway(s). Two pathways are descriBed to account for the differences in the final photooxidation products whose nature depends on the different modes of adsorption of the dye on the metal-oxide mediator. In the SRB/TiO2 system, when SRB is adsorBed on the positively charged TiO2 particle surface through a sulfonate group cleavage of the SRB chromophore structure predominates and N-de-ethylation occurs only to a slight extent with the major photooxidation products Being diethylamine and carBon dioxide. In the presence of the anionic dodecylBenzenesulfonate surfactant DBS, when SRB is near the negatively charged DBS/TiO2 interface through the positive diethylamine group N-de-ethylation occurs preferentially Before destruction of the structure with th...
Rene Csuk - One of the best experts on this subject based on the ideXlab platform.
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towards cytotoxic and selective derivatives of maslinic acid
Bioorganic & Medicinal Chemistry, 2014Co-Authors: Bianka Siewert, Elke Pianowski, Anja Obernauer, Rene CsukAbstract:Several novel esters and amides of maslinic acid were prepared. Their evaluation for cytotoxic activity with a panel of human cancer cell lines using a <B>SulforhodamineB> B (SRB) assay revealed for some of them a noteworthy activity. The results from annexinV-FITC and caspase-assays as well as from DNA laddering experiments provided evidence for an apoptotic cell death. A diacetylated Benzylamide (15) induced a G1/G0 arrest in tumor cells. It also displayed an extraordinary cytotoxicity against human ovarian cancer cells But a 300 times lower toxicity for non-malignant primary human fiBroBlasts.
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synthesis and antitumor activity of ring a modified glycyrrhetinic acid derivatives
European Journal of Medicinal Chemistry, 2011Co-Authors: Rene Csuk, Bianka Siewert, Stefan Schwarz, Ralph Kluge, Dieter StrohlAbstract:ABstract Triterpenoic acids show many pharmacological effects, among them an antiinflammatory or an antitumor activity. One of these, glycyrrhetinic acid ( 1 ) is of interest Because of its antitumor profile. Glycyrrhetinic acid is not only cytotoxic But also triggers apoptosis in various human tumor cell lines. To improve the cytotoxicity of parent 1 we set out to synthesize new derivatives of it – differing in structure and lipophilicity. These compounds were tested in a <B>SulforhodamineB> B assay for cytotoxicity, and screened for their aBility to induce apoptosis using an acridine orange/ethidium Bromide assay and trypan Blue staining. The most active compound, 34 , a Benzyl glycyrrhetinate holding an extra 3- N -(3-aminopropyl)glycyl suBstituent showed IC 50 Between 1.96 and 5.14 μm for five human cancer cell lines and triggers apoptosis in 80% of the cells.
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synthesis and antitumour activity of glycyrrhetinic acid derivatives
Bioorganic & Medicinal Chemistry, 2010Co-Authors: Stefan Schwarz, Rene CsukAbstract:ABstract Glycyrrhetinic acid (GA) is one of many interesting triterpenoic acids showing anticancerogenic potential. GA is known to trigger apoptosis in tumour cell lines, although GA has a low cytotoxicity. In our study we were aBle to prepare derivatives of GA that show lowered the IC 50 values as determined By a <B>SulforhodamineB> B (SRB) assay using 15 different human tumour cell lines. Thus, comBining an ester group comBined with the presence of an amino acid moiety led to a ca. 60-fold improved antitumor activity. Experiments on mouse emBryonic fiBroBlasts (NiH3T3) revealed that these compounds showed a Better selectivity for tumour cells compared to the parent compound GA. An apoptotic effect of some of these compounds was determined using an acridine orange/ethidium Bromide (AO/EB) test and DNA laddering experiments.
Susana P Pereira - One of the best experts on this subject based on the ideXlab platform.
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determination of metaBolic viaBility and cell mass using a tandem resazurin <B>SulforhodamineB> B assay
Current protocols in immunology, 2016Co-Authors: Filomena S G Silva, Irina G Starostina, Vilena V Ivanova, Albert A Rizvanov, Paulo J Oliveira, Susana P PereiraAbstract:The identification of rapid, reliaBle, and highly reproduciBle Biological assays that can Be standardized and routinely used in preclinical tests constitutes a promising approach to reducing drug discovery costs and time. This unit details a tandem, rapid, and reliaBle cell viaBility method for preliminary screening of chemical compounds. This assay measures metaBolic activity and cell mass in the same cell sample using a dual resazurin/<B>SulforhodamineB> B assay, eliminating the variation associated with cell seeding and excessive manipulations in assays that test different cell samples across plates. The procedure also reduces the amount of cells, test compound, and reagents required, as well as the time expended in conventional tests, thus resulting in a more confident prediction of toxic thresholds for the tested compounds. © 2016 By John Wiley & Sons, Inc.
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determination of metaBolic viaBility and cell mass using a tandem resazurin <B>SulforhodamineB> B assay
Current protocols in immunology, 2016Co-Authors: Filomena S G Silva, Irina G Starostina, Vilena V Ivanova, Albert A Rizvanov, Paulo J Oliveira, Susana P PereiraAbstract:The identification of rapid, reliaBle, and highly reproduciBle Biological assays that can Be standardized and routinely used in preclinical tests constitutes a promising approach to reducing drug discovery costs and time. This unit details a tandem, rapid, and reliaBle cell viaBility method for preliminary screening of chemical compounds. This assay measures metaBolic activity and cell mass in the same cell sample using a dual resazurin/<B>SulforhodamineB> B assay, eliminating the variation associated with cell seeding and excessive manipulations in assays that test different cell samples across plates. The procedure also reduces the amount of cells, test compound, and reagents required, as well as the time expended in conventional tests, thus resulting in a more confident prediction of toxic thresholds for the tested compounds. © 2016 By John Wiley & Sons, Inc. Keywords: high throughput; human skin fiBroBlasts; preclinical tests; toxicity evaluation
Wei Zhao - One of the best experts on this subject based on the ideXlab platform.
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photodegradation of <B>SulforhodamineB> B dye in platinized titania dispersions under visiBle light irradiation influence of platinum as a functional co catalyst
Journal of Physical Chemistry B, 2002Co-Authors: Wei Zhao, Chuncheng Chen, Xiangzhong Li, Jincai Zhao, Hisao Hidaka, Nick SerponeAbstract:The photooxidative degradation of <B>SulforhodamineB>-B dye (SRB) taking place in visiBle-light illuminated platinized titania dispersions is revisited to examine the influence of metallic platinum doped on TiO2 particles (Degussa P25 titania) By photocatalytic deposition from a hexachloroplatinic acid solution. The various TiO2/Pt specimens were characterized By transmission electron microscopy (TEM), UV−vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The self-photosensitized degradation of SRB mediated By TiO2/Pt specimens is 3-fold faster than that occurring on TiO2 alone under visiBle light irradiation and under otherwise identical conditions. That is, the TiO2/Pt system exhiBited greater catalytic activity than P25 TiO2 alone, which earlier proved to Be an effective photocatalyst in the degradation of dyes under visiBle illumination. A reaction mechanism is proposed on the Basis of a series of experiments that included spin−trap electron spin resonance (ESR) spectral resu...
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photodegradation of <B>SulforhodamineB> B dye in platinized titania dispersions under visiBle light irradiation influence of platinum as a functional co catalyst
Journal of Physical Chemistry B, 2002Co-Authors: Wei Zhao, Chuncheng Chen, Jincai Zhao, Hisao Hidaka, Nick SerponeAbstract:The photooxidative degradation of <B>SulforhodamineB>-B dye (SRB) taking place in visiBle-light illuminated platinized titania dispersions is revisited to examine the influence of metallic platinum dope...
