Academic literature on the topic 'Phenol compound'

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Journal articles on the topic "Phenol compound"

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Arvin, Erik, Bjørn K. Jensen, and Anders Torp Gundersen. "Biodegradation Kinetics of Phenols in an Aerobic Biofilm at Low Concentrations." Water Science and Technology 23, no. 7-9 (April 1, 1991): 1375–84. http://dx.doi.org/10.2166/wst.1991.0590.

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Aerobic biodegradation of the phenols: phenol, 2-methylphenol, 4-methylphenol, 2,4-dimethylphenol, 3,5-dimethylphenol and 2,4,6-trimethylphenol was studied in a biofilm reactor to establish kinetic constants under conditions where the phenols were the sole carbon sources. Phenol concentrations were very low, in the µg/l concentration range. 2,4,6-trimethylphenol was not degraded. The degradation of the other phenols was 1'st order at concentrations in the bulk phase below 20-50 µg/l. Zero order reaction seemed to govern the reaction above 200 µg/l. The l'st order rate constants are 3-30 times higher than the constants calculated for easily degradable organic compounds degraded at 100-1000 times higher concentrations (mg/l range). However, the maximum phenol utilization rates and the Monod constants were much lower compared with constants obtained for the microorganisms grown in the mg/l concentration range. The Monod constant was about 100 times lower. The removal of “total biodegradable phenol” (TB-phenol) was very similar to the removal of a specific compound. The degradation of TB-phenol was l'st order at concentrations below 200 µg/l. When the total biodegradable phenol degradation is near its maximum capacity (o'order reaction) there was a preferential degradation of the most easily degradable phenols, phenol and 2-methylphenol, leading to an apparent inhibition of the degradation of the more slowly degradable phenols, in particular 2,4-dimethylphenol and 3,5-dimethylphenol.
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MacDonald, David, and H. Brian Dunford. "Similarities in the optical spectra of prostaglandin H synthase during its cyclooxygenase and peroxidase reactions." Biochemistry and Cell Biology 67, no. 6 (June 1, 1989): 301–5. http://dx.doi.org/10.1139/o89-046.

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The spectral behavior of the enzyme prostaglandin H synthase was studied in the Soret region under conditions that permitted comparison of enzyme intermediates involved in peroxidase and cyclooxygenase activities. First, the peroxidase activity was examined. The enzyme's spectral behavior upon reacting with 5-phenyl-pent-4-enyl-1-hydroperoxide was different depending on the presence or absence of the reducing substrate, phenol. In the reaction of prostaglandin H synthase with the peroxide in the absence of phenol, formation of the enzyme intermediate compound I is observed followed by partial conversion to compound II and then by enzyme bleaching. In the reaction with both peroxide and phenol the absorbance decreases and a steady-state spectrum is observed which is a mixture of native enzyme and compound II. The steady state is followed by an increase in absorbance back to that of the native enzyme with no bleaching. The difference can be explained by the reactivity of phenol as a reducing substrate with the prostaglandin H synthase intermediate compounds. Cyclooxygenase activity with arachidonic acid could not be examined in the absence of diethyldithiocarbamate because extensive bleaching occurred. In the presence of diethyldithiocarbamate, enzyme spectral behavior similar to that seen in the reaction of the peroxide and phenol was observed. The similarity of the spectra strongly suggests that the enzyme intermediates involved in both the peroxidase and cyclooxygenase reactions are the same.Key words: prostaglandin H synthase, cyclooxygenase activity, peroxidase activity, arachidonic acid, compounds I and II of PGH synthase.
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Yang, Seungdo, Soyeon Jeong, Chunghyeon Ban, Hyungjoo Kim, and Do Heui Kim. "Catalytic Cleavage of Ether Bond in a Lignin Model Compound over Carbon-Supported Noble Metal Catalysts in Supercritical Ethanol." Catalysts 9, no. 2 (February 6, 2019): 158. http://dx.doi.org/10.3390/catal9020158.

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Decomposition of lignin-related model compound (benzyl phenyl ether, BPE) to phenol and toluene was performed over carbon-supported noble metal (Ru, Pd, and Pt) catalysts in supercritical ethanol without supply of hydrogen. Phenol and toluene as target products were produced by the hydrogenolysis of BPE. The conversion of BPE was higher than 95% over all carbon-supported noble metal catalysts at 270 ° for 4 h. The 5 wt% Pd/C demonstrated the highest yield (ca. 59.3%) of the target products and enhanced conversion rates and reactivity more significantly than other catalysts. In the case of Ru/C, BPE was significantly transformed to other unidentified byproducts, more so than other catalysts. The Pt/C catalyst produced the highest number of byproducts such as alkylated phenols and gas-phase products, indicating that the catalyst promotes secondary reactions during the decomposition of BPE. In addition, a model reaction using phenol as a reactant was conducted to check the secondary reactions of phenol such as alkylation or hydrogenation in supercritical ethanol. The product distribution when phenol was used as a reactant was mostly consistent with BPE as a reactant. Based on the results, plausible reaction pathways were proposed.
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Lu, C. J., and S. J. Chen. "The Effects of the Secondary Carbon Source on the Biodegradation of Chlorinated Phenols in Biofilm Reactors." Water Science and Technology 26, no. 9-11 (November 1, 1992): 2113–16. http://dx.doi.org/10.2166/wst.1992.0674.

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The effects of the presence of a secondary carbon source on the biodegradation of chlorinated phenols were studied with column biofilm reactors. The biodegradability of chlorinated phenols was studied with a series of batch reactors. The biodegradability of chlorinated phenols was to follow the order of phenol > 2,4-dichlorophenol > 4-chIorophenol > 2,4,6-trichlorophenol > 2-chlorophenol > 3-chloro-phenol. The presence of a relatively more biodegradable but higher chlorinated phenol, such as 2,4,6-trichlorophenol, enhanced the biodégradation of a less chlorinated butrecalcitrantphenol, such as 2-chlorophenol. The addition of phenol, an easily biodegradable compound, generally decreased the biodegradation of chlorinated phenols.
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Journal, Baghdad Science. "Preparation of some azo compounds by diazotization and coupling of 2- amino -5 – thiol -1,3,4- thiadizaole." Baghdad Science Journal 4, no. 2 (June 7, 2015): 271–75. http://dx.doi.org/10.21123/bsj.4.2.271-275.

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2- amino -5- thiol-1,3,4- thiadiazole (S1) was prepared by cyclic locking of thiosemicarbazide in the presence of anhydrous sodium carbonate and CS2. diazotization of (S1) compound gave diazonium salt (S2) that reacts with different activated aromatic compounds to get the following azo compounds ,2 [(4- aminophenyl) diazenyl ] 1,3,4- thiazdiazole-5- thiol (S3) ,2-[4-amino- 1-naphthyl diazenyl] -1,3,4 – thiazdiazole-5-thiol (S4) , 3-amino-4-[(5- mercapto -1,3,4- thiadiazole -2-yl) diazenyl ] phenol(S5) ,1-[(5-mercapto-1,3,4-thiadiazole-2-yl) diazenyl] -2-naphthol (S6) , 5-{[4-(dimethylamino) phenyl] diazenyl}-1,3,4-thiadiazole-2- thiol(S7) ,5-{[4-(diethylamino) phenyl] diazenyl}-1,3,4- thiadiazole-2- thiol(S8) ,2- amino-5-[(5-mercapto-1,3,4-thiadiazole-2-yl) diazenyl] phenol(S9) . All the prepared azo compounds have been characterized and identified through the study of their some physical, chemical and spectrometrical (U.V.I.R) properties.
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Chi, Mingmei, Xiaoli Su, Xiaojiao Sun, Yan Xu, Xiaoxia Wang, and Yanling Qiu. "Microbial analysis and enrichment of anaerobic phenol and p-cresol degrading consortia with addition of AQDS." Water Science and Technology 84, no. 3 (July 6, 2021): 683–96. http://dx.doi.org/10.2166/wst.2021.264.

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Abstract Quinones and humus are ubiquitous in the biosphere and play an important role in the anaerobic biodegradation and biotransformation of organic acids, poisonous compounds as well as inorganic compounds. The impact of humic model compound, anthraquinone-2, 6-disulfonate (AQDS) on anaerobic phenol and p-cresol degradation were studied. Four methanogenic AQDS-free phenol and p-cresol enrichments and two phenol-AQDS enrichments were obtained using two sludges with potential biodegradability of phenol and cresol isomers as inoculum. 16S rRNA gene-cloning analysis combined with fluorescence in situ hybridization revealed that syntrophic aromatic compound degrading bacterium Syntrophorhabdus aromaticivorans was dominant in four AQDS-free enrichments, whereas phenol degrading Cryptanaerobacter phenolicus was dominant in two phenol-AQDS enrichments. Neither co-culture of S. aromaticivorans with Methanospirillum hungatei nor two phenol-AQDS enrichments could metabolize phenol using AQDS as the terminal electron acceptor. Further degradation experiments suggested that C. phenolicus related microbes in two phenol-AQDS enrichments were responsible for the conversion of phenol to benzoate, and benzoate was further degraded by benzoate degraders of Syntrophus aciditrophicus or Sporotomaculum syntrophicum to acetate.
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Sithole, Bishop B., and David T. Williams. "Halogenated Phenols in Water at Forty Canadian Potable Water Treatment Facilities." Journal of AOAC INTERNATIONAL 69, no. 5 (September 1, 1986): 807–10. http://dx.doi.org/10.1093/jaoac/69.5.807.

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Abstract Samples of raw and treated water were collected once in each of 3 seasons at 40 potable water treatment plants across Canada and were analyzed for phenol and 33 halogenated phenolic compounds including chlorophenols, bromophenols, bromochlorophenols, and chloroguaiacols. Eighteen of the compounds were not found at any treatment plant; phenol and each of the remaining halogenated phenols were found in at least 1 sample. Pentachlorophenol was the only halogenated phenolic compound found in more than 20% of the raw water samples in the fall and winter samples at levels up to 53 ng/L with mean values of 1.9 and 2.8 ng/L, respectively. No halogenated phenols were detected in raw water summer samples. The halogenated phenols found most frequently in treated water samples were 4-chloro-, 2,4-dichloro-, 2,4,6- trichloro-, and bromodichlorophenols. Mean values were less than 15 ng/L and maximum values seldom exceeded 100 ng/L. Most of the positive values for the treated water samples were found at 8 of the 40 treatment plants but no correlations could be found between halogenated phenol levels and raw water type, treatment process, or chemical dosages.
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Nekrasova, Larisa P., A. G. Malysheva, and E. G. Abramov. "TRANSFORMATION OF PHENOL AND DIATOMIC PHENOLS IN SURFACE WATER UNDER THE IMPACT OF NATURAL PHYSICAL AND CHEMICAL FACTORS." Hygiene and sanitation 98, no. 11 (November 15, 2019): 1206–11. http://dx.doi.org/10.18821/0016-9900-2019-98-11-1206-1211.

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Introduction. Phenol, as well as diatomic phenols, are among the most common and priority organic pollutants of the environment. Getting into the water with sewage in real conditions of pollution, under the influence of natural physicochemical factors, phenols, as highly reactive compounds, undergo a transformation, as a result of which new, sometimes more toxic compounds may be formed. Purpose of the study is to investigate the transformation processes under the impact of the natural physicochemical factors of phenol, hydroquinone, pyrocatechin, and resorcinol in surface water. Material and methods. The processes of transformation of phenol and diatomic phenols were studied by the methods of spectrophotometry and luminescence spectroscopy. Absorption spectra were recorded with a UV-1800 spectrophotometer (Shimadzu, Japan), and fluorescence spectra were recorded on a CM2203 spectrofluorometer (Solar CJSC, Belarus). The degradation of phenols to CO2 and H2O (mineralization) at room temperature in natural samples was determined using a TOC-VCHP total carbon analyzer (Shimadzu, Japan). Results. The decrease in phenol concentration in river water was subject to linear dependence. The transformation kinetics of resorcinol corresponded to a sequential reaction. The processes of transformation of hydroquinone and pyrocatechin were dominated by chemical oxidation processes. Hydroquinone completely transformed within 24 hours. The degree of conversion of pyrocatechol 87.5% was achieved in 3 days and did not change during the month. During the month, the mineralization of phenol amounted to 90%, hydroquinone, and pyrocatechol - 55% and 45%, respectively. The complete transformation of resorcinol occurred in 7 days. A compound having a bright fluorescence and constituting a product of resorcinol polycondensation, whose concentration increased during the whole experiment, was formed. The degree of mineralization of resorcinol was 93%. Conclusion. The transformation of phenol, hydroquinone, pyrocatechin, and resorcinol in the surface water is caused by the processes of natural chemical and biochemical oxidation and depends on the chemical composition and concentration of presented impurities.
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Yu, Yuxiang, Xiaoqian Qiu, Chao Li, Defu Bao, and Jianmin Chang. "Performance and characterization of phenol-formaldehyde resin with crude bio-oil by model compound method." PLOS ONE 18, no. 1 (January 10, 2023): e0271478. http://dx.doi.org/10.1371/journal.pone.0271478.

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In order to clarify the effects of crude bio-oil for phenol-formaldehyde resin, the phenol-formaldehyde resin with bio-oil model compounds (BMPF) were prepared by model compound method. The bonding strength and aging resistance of BMPF were determined, and their microstructure and chemical bonds were also analyzed by scanning electron microscope, Fourier transform infrared spectroscopy, and nuclear magnetic resonance analysis, respectively. The results showed that the components of crude bio-oil had various degrees of effects on the BMPF performance, and the most obvious one is the phenols. The phenols and the ketones of bio-oil had positive effects on the bonding strength. The ketones had the biggest effect on the surface smoothness of BMPF film. But all components of bio-oil could inordinately improve the aging resistance of BMPF. The structural analysis indicated that the effects of bio-oil components on the BMPF performance by changing the resin structure. The CH2 peak in FT-IR and the methylene bridges intensity in NMR of phenol-free BMPF and ketone-free BMPF were smaller, while the results of aldehyde-free BMPF and acid-free BMPF were opposite. And the influence degree of BMPF structure was basically consistent with that of BMPF performance. These results could provide a basis for the modification of phenol-formaldehyde resin by crude bio-oil.
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Lu, C. J., and Y. H. Tsai. "The Effects of a Secondary Carbon Source on the Biodegradation of Recalcitrant Compounds." Water Science and Technology 28, no. 7 (October 1, 1993): 97–101. http://dx.doi.org/10.2166/wst.1993.0148.

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The effects of the addition of a secondary carbon source on the biodegradation of a chlorinated phenol were studied with a series of batch reactors. The biodegradability of chlorinated phenols was shown to follow the decreasing order: phenol > 2,4-DCP > 4CP > 2,4,6-TCP > 2CP > 3CP by the unacclimated microorganisms. The addition of a secondary carbon source may enhance or retard the biodegradation of a recalcitrant compound. The presence of a relatively easily biodegraded compound, such as 2,4-dichlorophenol, enhanced the biodegradation of a less chlorinated but recalcitrant compound, such as 2-chlorophenol. The enhancement of the removal efficiency of 2-chlorophenol was proportional to the concentration of 2,4-dichlorophenol. Monochlorophenols, such as 2-chlorophenol, 3-chlorophenol or 4-chlorophenol generally retarded the biodegradation of the relatively more highly chlorinated phenols, such as 2,4-dichlorophenol or 2,4,6-trichlorophenol.
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Dissertations / Theses on the topic "Phenol compound"

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Rehfuss, Marc Y. "Characterization and phylogenetic analysis of a phenol and halogenated aromatic compound degrading microbial consortium /." Search for this dissertation online, 2004. http://wwwlib.umi.com/cr/ksu/main.

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Rubió, Piqué Laura. "Phenol-enriched olive oil with its own phenolic compounds and complemented with phenols from thyme: a functional food development model." Doctoral thesis, Universitat de Lleida, 2014. http://hdl.handle.net/10803/146133.

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L'enriquiment de l’oli d'oliva amb els seus propis fenols esdevé una estratègia interessant per augmentar i normalitzar la ingesta diària d’hidroxitirosol sense augmentar el consum calòric. No obstant això, olis amb alt contingut fenòlic proporcionen un gust amarg que podria provocar rebuig entre els consumidors. A més, altes dosis d'hidroxitirosol podria tenir una acció pro-oxidant. En aquesta tesi es va plantejar l'estratègia d'enriquiment d’un oli d'oliva no només amb els seus propis fenols, sinó amb fenols complementaris d'herbes aromàtiques, concretament de farigola, amb la hipòtesi de que apart de proporcionar millores en l'estabilitat de l'oli i l'acceptació dels consumidors, també podria aportar beneficis addicionals per a la salut. Un cop desenvolupat l'oli d'oliva enriquit en fenols, es va avaluar la biodisponibilitat dels fenols mitjançant mètodes in vitro i in vivo, avaluant possibles interaccions o sinergies entre ambdues fonts fenòliques.
El enriquecimiento de aceite de oliva con sus propios fenoles se convierte en una estrategia interesante para aumentar y normalizar la ingesta diaria de hidroxitirosol sin aumentar el consumo calórico. Sin embargo, aceites con alto contenido fenólico tienen un sabor amargo que podría provocar rechazo entre los consumidores, y además sus altas dosis de hidroxitirosol podría tener una acción pro-oxidante. En esta tesis se planteó la estrategia de enriquecimiento de aceite de oliva no sólo con sus propios fenoles, sino con fenoles complementarios de hierbas aromáticas, concretamente tomillo, con la hipótesis de que no sólo podría proporcionar mejoras en la estabilidad del aceite y la aceptación de los consumidores, sino que podría aportar beneficios adicionales para la salud. Una vez desarrollado el aceite de oliva enriquecido se evaluó la biodisponibilidad de los fenoles mediante métodos in vitro e in vivo, evaluando posibles interacciones o sinergias entre ambas fuentes fenólicas.
The enrichment of olive oil with its own phenolic compounds becomes an interesting strategy to increase and standardize the daily intake of hydroxytyrosol without increasing the caloric intake. Concerning olive oils with high phenolic content, however, they have a bitter taste, which could promote a refusal among consumers, and contain high doses of hydroxytyrosol that could have a pro-oxidant action. In this context, the strategy of enriching olive oil not only with its own phenolics but also with complementary phenols from aromatic herbs was outlined in this thesis with the hypothesis that it could not only improve olive oil stability and consumers’ acceptation but also provide additional health benefits. In this thesis a phenol-enriched olive oil was developed using the aromatic herb of thyme, and the bioavailability of the phenolic compounds was assessed, evaluating possible interactions or synergies between both sources through in vitro and in vivo approaches.
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Wasser, Christian. "Synthese de derives phenoliques et etude de leur proprietes hypopigmentantes." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13191.

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Ce memoire presente les syntheses d'acyl-2 methoxy-4 phenols (a) d'alkyl-2 methoxy-4 phenols (b), d'alkyl-3 methoxy -4phenols (c), d'alkoxy-4 phenols (d) d'acide (hydroxy-4' phenyl)-3 methyl-2 propionique (e), d'acide (hydroxy-4' phenyl)-3 hydroxy-2 propionique, d'hydroxy-7 carboxy-3 tetrahydro-1,2,3,4 isoquinoleine et d'acide hydroxy-4 phenylpropargylique(f). L'etude "in vivo" (cobayes) et "in vitro" des proprietes hypopigmentantes des composes a, b, c, d, e et f. L'etude "in vivo" et "in vitro" des proprietes hypopigmentantes de substances naturelles : arbutine, luteoline, abscissine
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Scheffler, Thomas, Sascha Englich, and Michael Gehde. "Specific mold filling characteristics of highly filled phenolic injection molding compounds." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-198644.

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Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior. The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.
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Lepoittevin, Jean-Pierre. "Phenols, diphenols et cyclohexanediols a longues chaines derives d'allergenes naturels." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13103.

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Synthese par une nouvelle methode totalement stereoselective de trans,trans alkyl-3 cyclohexanediols-1,2. Synthese du cis,trans pentadecyl-3 cyclohexanediol-1,2. Activite allergisante et tolerogenique, vis a vis de l'urushiol de ces composes. Approche de la synthese de trans,trans alcenyl-3 cyclohexanediol-1,2. Isolement et structure des principaux composes aromatiques et lipidiques de ginkgo biloba l. Isolement et structure de nouvelles (-) alkyl-3 hydroxy-8 dihydro 3,4 isocoumarines. Isolement et structure de nouveaux nonacosanesdiols. Oxydation en position non activee, par l'acide metachloroperbenzoique des acides anacardiques et des cardanols. Activite allergisante des principaux aromatiques de ginkgo biloba l. Synthese d'un catechol porteur d'un complexe tris-bipyridyle du ruthenium comme sonde de microscopie electronique
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Scheffler, Thomas, Sascha Englich, and Michael Gehde. "Specific mold filling characteristics of highly filled phenolic injection molding compounds." Technische Universität Chemnitz, 2013. https://monarch.qucosa.de/id/qucosa%3A20416.

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Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior. The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.
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Oputu, Ogheneochuko Utieyin. "Advanced oxidation process using ozone/heterogeneous catalysis for the degradation of phenolic compounds (chlorophenols) in aqueous system." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2510.

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Thesis (DTech (Chemistry))--Cape Peninsula University of Technology, 2016.
The use of ozone as an advanced oxidation process is gathering wide spread attention with the major limitation to its application being its cost of operation and design considerations. While the general approach of most researches is to buttress the already known fact of the efficacy of the process, little attention is given to studying the by-products of ozone reactions with organics. The aims of this study were to investigate the efficacy of the ozonation process for removing recalcitrant phenolics: phenol, 2-chlorophenol (2CP), 4-chlorophenol (4CP) and 2,4-dichloropheno (2,4DCP) from aqueous medium with a view of understanding various reaction pathways of the process and identifying possible intermediates and residual compounds using liquid chromatography-mass spectrometry (LC-MS). The choice of the selected chlorophenols would also elucidate the role of the positioning of the chlorine atoms in determining reaction rates, pathways and subsequent mechanisms and by-products. Sequel to this, oxy-hydroxy iron in β-phase (β-FeOOH, akaganite) and various β-FeOOH bonded composites on support metal oxides (Al2O3, NiO and TiO2) were prepared via hetero-junction joining, and explored as a possible promoter to improve the efficiency of the ozonation process. Apparent first order reaction rates constants of tested phenolics was in the order 2,4-DCP > 2-CP > Phenol > 4-CP, irrespective of the tested pH. The individual rates however increased with increasing pH. The position 4 chlorine atom was found to be least susceptible to hydroxylative dechlorination. Catechol intermediate and pathway was identified as the major degradation pathway for phenol and 2-CP, while 4-chlorocatechol pathways were more important for 4-CP and 2,4-DCP. The formation of polymeric dimers and trimers by all compounds was pronounced at alkaline pH. Heterogeneous catalytic ozonation using β-FeOOH reduced ozonation time for 4-CP by 32%. Mechanism for β-FeOOH/ozone catalysis showed that the catalyst suffered reductive dissolution in acidic pH and the kinetics of 4-CP removal using the catalyst was best described using a two stage kinetic model. The first stage was attributed to heterogeneous catalysis of ozone breakdown on β-FeOOH surface generating faster reacting radicals, while the second stage was due to homogeneous catalysis by reduced Fe2+ ions in solution. β-FeOOH stabilized on NiO at a 5% ratio exhibited superior catalytic property compared to the other tested composites. Characterization by high-resolution transmission electron microscopy (HRTEM) affirmed a β-FeOOH-NiO bonded interfaced composite which was stable as a iv catalyst over four (4) recycle runs. The mechanism of operation of the composite was via an increased ozone breakdown to radicals as monitored via photoluminescence experiments. The composite material produced satisfactory results when tested on real wastewater samples. Results from this study contribute to the current understanding on reaction mechanisms for ozone with phenols and chlorophenols, for the first time monitoring time captured intermediates via liquid chromatography-mass spectrometric method, which preserves the integrity of reaction intermediates. Also this study proposes heterogeneous catalysts; β-FeOOH and β-FeOOH bonded composites as possible improvements for simple ozone based water purification systems.
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Avci, Gulden. "Analysis Of Phenol Oxidation Products By Scytalidium Thermophilum Bifunctional Catalase/phenol Oxidase (catpo)." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613770/index.pdf.

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This thesis was aimed to analyze phenol oxidation by the bifunctional catalase/phenol oxidase of the thermophilic fungus Scytalidium thermophilum. Several reactive oxygen species (ROS) are continuously produced in fungi under oxidative stress. Depending on the nature of the ROS species, some are highly toxic and are rapidly detoxified by various cellular enzymatic mechanisms, including the production of catalase. S. thermophilum produces a novel bifunctional catalase-phenol oxidase (CATPO) which is capable of oxidizing phenolics in the absence of hydrogen peroxide. Phenol oxidases convert phenolic compounds to quinones, which are then polymerized mainly by free- radical mediated reactions. In this study, 14 phenolic compounds were selected according to their different chemical structures and functional properties and were analyzed as substrates of CATPO. Among 14 phenolic compounds, only in catechol, chlorogenic acid, catechin and caffeic acid distinct oxidation products were observed by HPLC. The oxidation products of catechol, caffeic acid, chlorogenic acid and catechin were characterized by LC-ESI-MS. Dimer, trimer, tetramer and oligomer formations were detected. While the maximum conversion efficiency, at 1 hour of reaction, was observed with catechin, minimum conversion efficiency was attained by caffeic acid, under the specified conditions. The oxidation products observed after oxidation of catechol, chlorogenic acid, catechin and caffeic acid by CATPO was compared with the same phenolic compounds oxidation products oxidized by laccase and tyrosinase. CATPO was incapable of oxidizing tyrosinase and laccase-specific substrates tyrosine and ABTS respectively. However, the oxidizing spectrum of substrates indicates that the nature of phenol oxidation by CATPO appears to resemble mainly those of laccase.
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Kalili, Kathithileni Martha. "Application of comprehensive 2-dimensional liquid chromatography for the analysis of complex phenolic fractions." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2420.

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Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009.
ENGLISH ABSTRACT: The separation of apple, cocoa and green tea phenolic compounds by comprehensive 2-dimensional liquid chromatography (2-D-LC) has been studied. In the first dimension, phenolic compounds were separated according to polarity by hydrophilic interaction chromatography (HILIC) on a diol stationary phase with a mobile phase containing acetonitrile, methanol, acetic acid and water. Gradient reversed-phase (RP) LC using a C18 column with fluorescence detection was employed in the second dimension to separate compounds according to hydrophobicity. Compounds were identified using negative electrospray ionisation mass spectrometry (ESI-MS) coupled to both HILIC and RP separations. The coupling of HILIC and RP separations proved to be especially beneficial since this provided simultaneous information on both the polarity and hydrophobicity of phenolics. The low degree of correlation (r2 < 0.21) between the two LC modes afforded peak capacities in excess of 3000 for the off-line method. An on-line method was also developed utilizing a short, small particle-packed column to provide fast separation in the second dimension. A 1 mm i.d. column was used in the first dimension for the on-line system to reduce injection volumes onto the second dimension column. A significantly lower practical peak capacity was measured for the on-line system, due largely to the reduction in second dimension peak capacity. On the other hand, analysis could be performed in an automated fashion using the online system reducing the risk of sample alteration and guaranteeing better operation reliability and reproducibility. Especially the off-line comprehensive HILIC × RP-LC method developed demonstrated its utility in the analysis of various groups of phenolic compounds including proanthocyanidins, phenolic acids, flavonols and flavonol conjugates in a variety of natural products.
AFRIKAANSE OPSOMMING: Die skeiding van fenoliese komponente in appel, kakao en groen tee is deur middel van ‘comprehensive’ 2-dimensionele vloeistof chromatografie (2-D-LC) bestudeer. Hidrofiliese interaksie chromatografie (HILIC) is gebruik om die fenoliese komponente in die eerste dimensie te skei op grond van polariteit, deur gebruik te maak van ‘n diol stationêre fase en mobiele fase bestaande uit asetonitriel, metanol, asynsuur en water. ‘n Gradiënt omgekeerde fase (RP) LC analisie op ‘n C18 kolom met fluorosensie deteksie is in die tweede dimensie gebruik om fenole volgens hidrofobisiteit te skei. Negatiewe elektrosproei-ionisasie massa spektometrie (ESIMS) gekoppel aan HILIC en RP skeidings is gebruik vir identifikasie van fenole. Die koppeling van HILIC en RP skeidings veral voordelig deurdat dit gelyktydige informasie verskaf het oor die polariteit sowel as die hidrofobisiteit van die fenoliese komponente. Die lae graad van korrelasie (r2 < 0.21) tussen die twee LC metodes was verantwoordelik vir piek kapasiteite bo 3000 vir die af-lyn metode. ‘n Aanlyn metode was ontwikkel deur gebruik te maak van ‘n kort, klein partikel gepakte kolom om vinnige skeiding in die tweede dimensie te verseker. 1 mm i.d. kolom was gebruik in die eerste dimensie vir die aanlyn sisteem om die inspuit volume op die tweede dimensie kolom te verminder. Aansienlike laer praktiese piek kapasiteit was gemeet vir die aanlyn sisteem, grootliks toegeskryf aan die reduksie in die tweede dimensie piek kapasitiet. Aan die ander kant, analise kan geoutomatiseerd uitgevoer word deur gebruik te maak van die aanlyn sisteem, wat monster alterasie, beter betroubaarheid en reproduseerbaarhied verseker. Veral die ontwikkelde af-lyn ‘comprehensive’ HILIC × RP-LC metode toon demonstreerbare voordele vir die analiese van verskeie groepe fenoliese komponente, insluitende proantosianiede, fenoliese sure, flavonole en gekonjugeerde flavonole in ‘n verskeidenheid natuurlike produkte.
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Shewmaker, Patricia Lynn Wallace. "Enhanced biodegradation of phenolic compounds and cellular fatty acid analysis of bacteria using infrared pyrolysis/gas chromatography-mass spectrometry." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/25732.

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Books on the topic "Phenol compound"

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Juha, Kallas, and Lappeenrannan teknillinen korkeakoulu, eds. Treatment technology of wastewater containing phenols and phenolic compounds. Lappeenranta: Lappeenranta University of Technology, 1992.

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Wilfred, Vermerris. Phenolic compound biochemistry. Dordrecht: Springer, 2006.

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Wilfred, Vermerris. Phenolic compound biochemistry. Dordrecht: Springer, 2006.

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Wilfred, Vermerris. Phenolic compound biochemistry. Dordrecht: Springer, 2006.

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Vermerris, Wilfred. Phenolic compound biochemistry. Dordrecht: Springer, 2008.

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Nollet, Leo M. L., and Janet Alejandra Gutierrez-Uribe, eds. Phenolic Compounds in Food. Boca Raton : CRC Press, Taylor & Francis Group, 2018.: CRC Press, 2018. http://dx.doi.org/10.1201/9781315120157.

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Molinarolo, William E. The high temperature alkaline degradation of phenyl B-D-glucopyranoside. Appleton, WI: Institute of Paper Chemistry, 1989.

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Nicholas, David Henry. Complexation of borates by phenol-formaldehyde resins and related compounds. Birmingham: University of Birmingham, 1990.

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Moussa, Lina Z. Anaerobic digestion of toxic phenolic compounds. Birmingham: University of Birmingham, 1998.

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Ghoul, Mohamed, and Latifa Chebil. Enzymatic polymerization of phenolic compounds by oxidoreductases. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-3919-2.

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Book chapters on the topic "Phenol compound"

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Colclough, Nicola, and John R. Lindsay Smith. "Models for Horseradish Peroxidase Compound II: Phenol Oxidation with Oxoiron(IV) Porphyrins." In The Activation of Dioxygen and Homogeneous Catalytic Oxidation, 171–82. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-3000-8_13.

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Malhotra, Milan, Divya Gupta, Jeetendra Sahani, and Sanjay Singh. "Microbial Degradation of Phenol and Phenolic Compounds." In Recent Advances in Microbial Degradation, 297–312. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0518-5_11.

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Mello, Beatriz. "Phenolic Compound." In Encyclopedia of Membranes, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-40872-4_458-4.

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Knop, Andre, and Louis A. Pilato. "Molding Compounds." In Phenolic Resins, 196–212. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-662-02429-4_12.

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Al-Obaidi, Mudhar A., Chakib Kara-Zaïtri, and Iqbal M. Mujtaba. "The Removal of Phenol and Phenolic Compounds from Wastewater Using Reverse Osmosis." In Water Management, 191–227. First editor. | Boca Raton : Taylor & Francis, a CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa, plc, [2019] | Series: Green chemistry and chemical engineering: CRC Press, 2018. http://dx.doi.org/10.1201/b22241-11.

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Koizumi, Koji, Ted Charles, and Hendrik De Keyser. "Phenolic Molding Compounds." In Phenolic Resins: A Century of Progress, 383–437. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-04714-5_16.

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Shahidi, Fereidoon. "Phenolic Compounds ofBrassicaOilseeds." In ACS Symposium Series, 130–42. Washington, DC: American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0506.ch010.

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Lattanzio, Vincenzo. "Phenolic Compounds: Introduction." In Natural Products, 1543–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-22144-6_57.

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Santana-Gálvez, Jesús, and Daniel A. Jacobo-Velázquez. "Classification of Phenolic Compounds." In Phenolic Compounds in Food, 3–20. Boca Raton : CRC Press, Taylor & Francis Group, 2018.: CRC Press, 2018. http://dx.doi.org/10.1201/9781315120157-1.

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Gambuti, Angelita, and Luigi Moio. "Phenolic Compounds in Wines." In Phenolic Compounds in Food, 291–318. Boca Raton : CRC Press, Taylor & Francis Group, 2018.: CRC Press, 2018. http://dx.doi.org/10.1201/9781315120157-15.

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Conference papers on the topic "Phenol compound"

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Priatna, Rachmat, Edi Syahbandi, and Bambang Sudewo. "Phenol Compound in Produced Water." In SPE Health, Safety and Environment in Oil and Gas Exploration and Production Conference. Society of Petroleum Engineers, 1994. http://dx.doi.org/10.2118/27134-ms.

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"Photolytic Oxidation of Hazardous Organic Compound: Phenol." In International Conference on Chemical, Environmental and Biological Sciences. International Institute of Chemical, Biological & Environmental Engineering, 2015. http://dx.doi.org/10.15242/iicbe.c0315027.

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Oboirien, Bilainu O., P. E. Molokwane, and Evans M. N. Chirwa. "Bioremediation of Organic Pollutants in a Radioactive Wastewater." In The 11th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2007. http://dx.doi.org/10.1115/icem2007-7014.

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Bioremediation holds the promise as a cost effective treatment technology for a wide variety of hazardous pollutants. In this study, the biodegradation of organic compounds discharged together with radioactive wastes is investigated. Nuclear process wastewater was simulated by a mixture of phenol and strontium, which is a major radionuclide found in radioactive wastewater. Phenol was used in the study as a model compound due to its simplicity of molecular structure. Moreover, the biodegradation pathway of phenol is well known. Biodegradation studies were conducted using pure cultures of Pseudomonas aeruginosa and Pseudomonas putida. The rate of phenol degradation by both species was found to be higher in the test without strontium. This suggests some degree of inhibition in the degradation of phenol by strontium. There was no phenol degradation in the sterile controls. The results indicate the feasibility of the biodegradation of organic pollutants discharged in radioactive effluents by specialised microbial cultures.
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Zhibo, Zhang, Siyamak Shahab, and A. Labanava. "QUANTUM-CHEMICAL CALCULATION OF N-(2-hydroxy-3,5-diisopropylpheny) benzene sulfonamide COMPOUND." In SAKHAROV READINGS 2022: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute of Belarusian State University, 2022. http://dx.doi.org/10.46646/sakh-2022-2-403-405.

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This paper represents theoretical calculations related to newly synthetized phenol compound for defining its optimized geometry, free energy and form of molecular orbitals participated in formation of UV/Vis spectrum.
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Zhang, Danyang, Zhiguo Tang, and Qingqing Liu. "Experimental Study of Phenol as Biomass Tar Model Compound Gasification for Hydrogen." In International Conference on Advances in Energy, Environment and Chemical Engineering. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/aeece-15.2015.167.

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Zhao, Hefei, and Selina Wang. "Isolation and purification phenolic compounds in California olive pomace by pilot-scale C18 gel chromatography." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/hkjz6249.

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According to the Food and Agriculture Organization, the United States (mainly in California) produced 151,950 tons of olives in 2019, which resulted in a large amount of pomace waste. While many researchers focused on crude extraction and macroporous resin purification from European olive pomace on an analytical scale, few studies have been conducted to isolate fractions of US olive pomase (OP) by pilot-scale C18 chromatography. Hexane defatted Arbequina California OP was extracted by water, and the extract was loaded to a pilot-scale chromatography column with 262.5 mL C18 gel, and the elute syrup (ES) was collected. Desorptions were applied by 1 L of acidified water (AW), 35% methanol (35M) and 70% methanol (70M), respectively. The fractions were concentrated then freeze-dried. Total phenol contents (TPC) were measured by Folin-Ciocalteu assay. Individual phenols were determined by HPLC-DAD. Results showed that the TPC of the fractions of ES, AW, 35M and 70M were 2.88, 29.39, 170.56 and 235.96 mg gallic acid equivalents/g, respectively. Heatmap cluster analysis showed that ES and AW fractions had similar phenol profiles with hydroxytyrosol and tyrosol-glucoside; and 35M had hydroxytyrosol-glucoside, hydroxytyrosol, tyrosol-glucoside, 4-hydroxyphenylacetic acid (4-HPA), verbascoside and oleuropein; 70M contained hydroxytyrosol, tyrosol-glucoside, tyrosol, but generally had more nonpolar compounds such as verbascoside, rutin and oleuropein. Very interestingly, the 3,4-DHPEA-EDA in water extract at 31.43 min disappeared in 35M and 70M fractions, meanwhile a new peak at 29.25 min showed up which could be a new compound derived from 3,4-DHPEA-EDA possibly because of the acidified process. This study could be the first-ever report of phenol profile of pilot-scale C18 fractions of the US OP. This new data on the chemical compositions of the OP C18 fractions provides practical knowledge for the valorization and industrial food applications of the US olive wastes.
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"Antimicrobial Activity of 2-Nitro-6-[(4-Phenyl-Benzo[4,5]imidazo[1,2-a] Pyrimidin-2-ylimino)-Methyl]-Phenol: A Novel Schiff Base Compound." In Nov. 27-28, 2017 South Africa. EARES, 2017. http://dx.doi.org/10.17758/eares.eap517211.

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A.V., Firsova, Polovinkina M.A., Grigoriev V.A., Osipova V.P., and Kudryavtsev K.V. "EFFECT OF NEW PHENOL DERIVATIVES WITH PYRROLIDINE FRAGMENT ON THE REPRODUCTIVE PROPERTIES OF STURGEON GAMETES." In II INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE "DEVELOPMENT AND MODERN PROBLEMS OF AQUACULTURE" ("AQUACULTURE 2022" CONFERENCE). DSTU-Print, 2022. http://dx.doi.org/10.23947/aquaculture.2022.154-156.

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The influence of new phenolic derivatives of pyrrolidine on the quality of native sturgeon sperm and on the fertility of eggs was assessed in comparison with the well-known antioxidant - ionol. The high efficiency of (L)-1-(2-((1-hydroxynaphthalen-2-yl)thio)acetyl)pyrrolidine-2-carboxylic acid was shown, the addition of this compound increases the time of forward movement of spermatozoa by 2.2 times relative to the control and an increase in the percentage of fertilization and hatching of prelarvae by about 1.5 times. The results obtained indicate the need for additional studies to establish the cryoprotective activity of these derivatives under conditions of deep freezing and defrosting.
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Kusumaningrum, Vivi Ambar, Ahmad Hanapi, Rachmawati Ningsih, Sri Ani Nafiah, and Ainun Nadhiroh. "Synthesis, Characterization, and Antioxidant Activity of 2-methoxy-4 - ((4-methoxy phenyl imino) -methyl) phenol compounds." In International Conference on Engineering, Technology and Social Science (ICONETOS 2020). Paris, France: Atlantis Press, 2021. http://dx.doi.org/10.2991/assehr.k.210421.042.

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Šaćirović, Sabina, Andrija Ćirić, Mališa Antić, and Zoran Marković. "HPLC ANALYSIS OF PHENOLS OF SLOVENIAN RED WINES: CABERNET SAUVIGNON AND MERLOT." In 1st INTERNATIONAL Conference on Chemo and BioInformatics. Institute for Information Technologies, University of Kragujevac, 2021. http://dx.doi.org/10.46793/iccbi21.165s.

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In this study, HPLC-DAD rapid analysis of phenols in wine samples was performed. The recording was performed at different wavelengths: phenolic acid (254nm), flavan-3-ols and stilbene (280nm), flavonoids (340nm) and anthocyanins (520nm). In selected wines, the concentrations of the following compounds were determined and expressed in mg/l of wine. The isolated derivatives were: hydroxybenzoic acids, derivatives of caffeic, ferulic, syringic, and vanillic acids, catechin (flavanol), rutin, myricetin and quercetin (flavonols), and the stilbene derivative-resveratrol. The properties and quantities of phenolic compounds in organic wines were investigated. The results show the content of phenolic compounds in organic wines do not differ qualitatively and quantitatively from those in conventional wines. Wine samples have shown good antioxidative activity according to both DPPH and FRAP analysis, which indicates the good antioxidative potential and high antioxidant concentration in tested wines. Cabernet Sauvignon wines have shown better radical scavenging activity than Merlot, especially when the DPPH test was considered.
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Reports on the topic "Phenol compound"

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Cerquido, Ana Sofia, Martin Vojtek, Rita Ribeiro-Oliveira, Olga Viegas, Joana Beatriz Sousa, Isabel M. P. L. V. O. Ferreira, and Carmen Diniz. Unravelling potential health‐beneficial properties of Corema album phenolic compounds: a systematic review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, August 2022. http://dx.doi.org/10.37766/inplasy2022.8.0022.

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Review question / Objective: A systematic review of the literature was carried out to summarize the phenolic compounds and bioactive properties identified in C. album berries and leaves and search for research gaps on this topic. Condition being studied: Summarize the phenolic compound's composition of Corema album berries and leaves assessed by advanced analytical methods and assessment of their bioactive properties. Information sources: Three databases PubMed, SCOPUS, and Web of Science as information sources. The following keywords were used: (“Corema album” AND (berries OR leaves)). Contact with authors or grey literature was not used as information source.
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Grant, T. M., and C. J. King. Irreversible adsorption of phenolic compounds by activated carbons. Office of Scientific and Technical Information (OSTI), December 1988. http://dx.doi.org/10.2172/6416993.

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Nelson, Nicholas. Catalytic upgrading of phenolic compounds using ceria-based materials. Office of Scientific and Technical Information (OSTI), November 2016. http://dx.doi.org/10.2172/1593322.

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Ozkan, Gursel. Phenolic Compounds, Organic Acids, Vitamin C and Antioxidant Capacity in Prunus spinosa L. Fruits. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, February 2019. http://dx.doi.org/10.7546/crabs.2019.02.17.

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Choudhary, Ruplal, Victor Rodov, Punit Kohli, John D. Haddock, and Samir Droby. Antimicrobial and antioxidant functionalized nanoparticles for enhancing food safety and quality: proof of concept. United States Department of Agriculture, September 2012. http://dx.doi.org/10.32747/2012.7597912.bard.

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General concept. The reported 1-year study tested the feasibility ofpreparing antimicrobial and antioxidant nanoparticlesfunctionalized with natural phenolic compounds, as a first step to reach the ultimate goal - improving safely and quality of foods by developing novel antimicrobial and antioxidant food-contacting materials. The secondary objectives of the study were (a) selecting the most promising phenoliccompounds, (b) building nanoparticles with the selected phenolicgrafted on their Surface, and (c) testing antimicrobial and antioxidant properties of these particles. The study was expected to provide a " go/no go" decision as concerning the prospects of phenolic- bound nanoparticles as antimicrobial and antioxidant agents. Results. In course of the feasibility study, curucminwas chosen as the most promising phenoliccompound due to its high antibacterial activity exceeding other tested compounds by at leas one order of magnitude. Lipsome-typephospholipid/polydiacetylene(PDA) nanoparticlesfunctionalizedwith curcuminwere successfully built. The pitfall of limited curcumin amount that could be covalently bound to theparticle surface was circumvented by inclusion of curcunun in the liposome body. It was suggested onthe basis of fluorescence spectroscopy that curcuminwas bound by hydrophobic forces in the bi1ayer periphery of the Liposomesand therefore mightexert a contact effect on microorganisms. The curcumin­ functionalizednanoparticles(CFN) were shown to have a strong bactericidal activity towards both Gram-negative (E. coli) and Gram-positive (B. ce,·e11s) bacteria, but only limited effect against yeast. Furthermore, beyond the originallyplanned objectives, preliminary trials showed that CFN could be bound to silanized glass surface rendering aנבtiנnicrobial activity to the glass. Tnaddition, the particles showed antioxidantcapacity. Tberefore, it ,vas co11cluded tlוattlוeaims of tlוefeasibility study bad been successfully reached an
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Naim, Michael, Gary R. Takeoka, Haim D. Rabinowitch, and Ron G. Buttery. Identification of Impact Aroma Compounds in Tomato: Implications to New Hybrids with Improved Acceptance through Sensory, Chemical, Breeding and Agrotechnical Techniques. United States Department of Agriculture, October 2002. http://dx.doi.org/10.32747/2002.7585204.bard.

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The tomato, a profitable vegetable crop in both the USA and Israel, has benefited significantly from intensive breeding efforts in both countries, and elsewhere (esp. Holland). : Modem hybrids are highly prolific and resistant to a variety of major pests. They produce attractive, firm fruit for both processing and fresh-marketing. In all cases, however, reduction in flavor and aroma have occurred concomitantly with the increase in yield. Sugars-acids ratio dominate fruit taste, whereas aroma volatiles (potent at minute ppb and ppt levels) contribute to the total characteristic tomato flavor. An increase in sugars (1-2%) contributes significantly to tomato fruit taste. However, because of energy reasons, an increase in fruit sugars is immediately compensated for by a decrease in yield. Our main objectives were to: (a) pinpoint and identify the major impact aroma components of fresh tomato; (b) study the genetic and environmental effects on fruit aroma; (c) determine precursors of appealing (flavors) and repelling (off-flavors) aroma compounds in tomato. Addition of saturated salts blocked all enzymatic activities prior to isolation of volatiles by dynamic and static headspace, using solvent assisted flavor evaporation (SAFE) and solid phase micro-extraction (SPME) from highly favored (FA-612 and FA-624) and less preferred (R 144 and R 175) tomato genotypes. Impact aroma components were determined by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC- MS) and aroma extract dilution analysis (AEDA). The potent odorant (Z)-1,5-octadien-3-one, was identified for the first time in fresh tomato. From the ca. 400 volatile compounds in the headspace of fresh tomato, the following compounds are proposed to be impact aroma compounds: (Z)-3-hexenal, hexanal, 1-penten-3-one, 2-phenylethanol, (E)-2-hexenal, phenyl acetaldehyde, b-ionone, b-damascenone, 4-hydroxy-2,5-dimethyl-3-(2H)-furanone (FuraneolR), (Z)-l,5-octadien-3-one, methional, 1-octen-3-one, guaiacol, (E,E)- and (E,Z)- 2,4-decadienal and trans- and cis-4,5-EPOXY -(E)-2-decenal. This confirms the initial hypothesis that only a small number of volatiles actually contribute to the sensation of fruit aroma. Tomato matrix significantly affected the volatility of certain impact aroma components and thus led to the conclusion that direct analysis of molecules in the headspace . may best represent access of tomato volatiles to the olfactory receptors. Significant differences in certain odorants were found between preferred and less-preferred cultivars. Higher consumer preference was correlated with higher concentrations of the following odorants: l-penten-3-one, (Z)-3-hexenal, (E,E)- and (E,Z)-2,4-decadienal and especially Furaneol, whereas lower consumer preference was associated with higher concentrations of methional, 3-methylbutyric acid, phenylacetaldehyde, 2-phenylethanol, and 2-isobutylthiazole. Among environmental factors (salinity, N source, growth temperature), temperature had significant effects on the content of selected aroma compounds (e.g., 3-methylbutanal, 1- penten-3-one, hexanal, (Z)-3-hexenal, (E)-2-hexenal, 2-isobutylthiazole, 6-methyl-5-hepten- 2-one, 1-octen-3-one, methional, 2-phenylethanal, phenyl acetaldehyde, and eugenol) in fresh tomatoes. Salt stress (20 mM NaCl) increased the content of odorants such as (Z)-3-hexenal, 2-phenylethanol and 3-methylbutanal in the R-144 cultivar whereas salinity had minor effects on 1-pentene-3-one, 2-isobutylthiazole and b-ionone. This fundamental knowledge obtained by comprehensive investigation, using modem chemical, sensory and agrotechnical methodology will assist future attempts to genetically modify the concentrations of key odorants in fresh tomatoes, and thus keep the tomato production of Israel and the USA competitive on the world market.
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Kanner, Joseph, Edwin Frankel, Stella Harel, and Bruce German. Grapes, Wines and By-products as Potential Sources of Antioxidants. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7568767.bard.

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Several grape varieties and red wines were found to contain large concentration of phenolic compounds which work as antioxidant in-vitro and in-vivo. Wastes from wine production contain antioxidants in large amounts, between 2-6% on dry material basis. Red wines but also white wines were found to prevent lipid peroxidation of turkey muscle tissues stored at 5oC. The antioxidant reaction of flavonoids found in red wines against lipid peroxidation were found to depend on the structure of the molecule. Red wine flavonoids containing an orthodihydroxy structure around the B ring were found highly active against LDL and membrane lipid peroxidation. The antioxidant activity of red wine polyphenols were also found to be dependent on the catalyzer used. In the presence of H2O2-activated myoglobin, the inhibition efficiency was malvidin 3-glucoside>catechin>malvidin>resveratol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratol>malvidin 3-glucoside = malvidin>catechin. Differences in protein binding were found to affect antioxidant activity in inhibiting LDL oxidation. A model protein such as BSA, was investigated on the antioxidant activity of phenolic compounds, grape extracts, and red wines in a lecithin-liposome model system. Ferulic acid followed by malvidin and rutin were the most efficient in inhibiting both lipid and protein oxidation. Catechin, a flavonal found in red-wines in relatively high concentration was found to inhibit myoglobin catalyzed linoleate membrane lipid peroxidation at a relatively very low concentration. This effect was studied by the determination of the by-products generated from linoleate during oxidation. The study showed that hydroperoxides are catalytically broken down, not to an alcohol but most probably to a non-radical adduct. The ability of wine-phenolics to reduce iron and from complexes with metals were also demonstrated. Low concentration of wine phenolics were found to inhibit lipoxygenase type II activity. An attempt to understand the bioavailability in humans of antocyanins from red wine showed that two antocyanins from red wine were found unchanged in human urine. Other antocyanins seems to undergo molecular modification. In hypercholesterolemic hamsters, aortic lipid deposition was significantly less in animals fed diets supplemented with either catechin or vitamin E. The rate of LDL accumulation in the carotid arteries was also significantly lower in the catechin and vitamin E animal groups. These results suggested a novel mechanism by which wine phenolics are associated with decreased risk of coronary heart diseases. This study proves in part our hypothesis that the "French Paradox" could be explained by the action of the antioxidant effects of phenolic compounds found at high concentration in red wines. The results of this study argue that it is in the interest of public health to increase the consumption of dietary plant falvonoids. Our results and these from others, show that the consumption of red wine or plant derived polyphenolics can change the antioxidant tone of animal and human plasma and its isolated components towards oxidative reactions. However, we need more research to better understand bioavailability and the mechanism of how polyphenolics affect health and disease.
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8

Yu, S. K.-T., R. P. Vrana, and J. B. Green. Retention indices, relative response factors, and mass spectra of trifluoroacetate esters of phenolic compounds determined by capillary GC/MS: Topical report. Office of Scientific and Technical Information (OSTI), April 1989. http://dx.doi.org/10.2172/6421637.

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9

Richardson, Curtis John, Neal Flanagan, Hongjun Wang, Mengchi Ho, Jeff Chanton, and Bill Cooper. Phenolic compounds and black carbon feedback controls on peat decomposition and carbon accumulation in southeastern peatlands under regimes of seasonal drought, drainage and frequent fire. Office of Scientific and Technical Information (OSTI), December 2018. http://dx.doi.org/10.2172/1488733.

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10

Carpita, Nicholas C., Ruth Ben-Arie, and Amnon Lers. Pectin Cross-Linking Dynamics and Wall Softening during Fruit Ripening. United States Department of Agriculture, July 2002. http://dx.doi.org/10.32747/2002.7585197.bard.

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Abstract:
Our study was designed to elucidate the chemical determinants of pectin cross-linking in developing fruits of apple and peach and to evaluate the role of breakage cross-linkages in swelling, softening, and cell separation during the ripening. Peaches cell walls soften and swell considerably during the ripening, whereas apples fruit cells maintain wall firmness but cells separate during late stages of ripening. We used a "double-reduction" technique to show that levels of non-methyl esters of polyuronic acid molecules were constant during the development and ripening and decreased only in overripe fruit. In peach, methyl and non-methyl esters increased during the development and decreased markedly during the ripening. Non-methyl ester linkages in both fruit decreased accompanied fruit softening. The identity of the second component of the linkage and its definitive role in the fruit softening remain elusive. In preliminary examination of isolated apples cell walls, we found that phenolic compounds accumulate early in wall development but decrease markedly during ripening. Quantitative texture analysis was used to correlate with changes to wall chemistry from the fresh-picked ripe stage to the stage during storage when the cell separation occurs. Cell wall composition is similar in all cultivars, with arabinose as the principal neutral sugar. Extensive de-branching of these highly branched arabinans pre-stages softening and cell-cell separation during over-ripening of apple. The longer 5-arabinans remain attached to the major pectic polymer rhamnogalacturonan I (RG I) backbone. The degree of RG I branching, as judged from the ratios of 2-Rha:2,4-Rha, also decreases, specially after an extensive arabinan de-branching. Loss of the 4-Rham linkages correlated strongly with the softening of the fruit. Loss of the monomer or polymer linked to the RG I produce directly or indirectly the softening of the fruit. This result will help to understand the fruit softening and to have better control of the textural changes in fruit during the ripening and especially during the storage. 'Wooliness', an undesirable mealy texture that is induced during chilling of some peach cultivars, greatly reduces the fruit storage possibilities. In order to examine the hypothesis that the basis for this disorder is related to abnormality in the cell wall softening process we have carried out a comparative analysis using the resistant cultivar, Sunsnow, and a sensitive one, Hermosa. We investigated the activity of several pectin- and glycan-modifying enzymes and the expression of their genes during ripening, chilling, and subsequent shelf-life. The changes in carbohydrate status and in methyl vs. non-methyl uronate ester levels in the walls of these cultivars were examined as well to provide a basis for comparison of the relevant gene expression that may impact appearance of the wooly character. The activities of the specific polygalacturonase (PGase) and a CMC-cellulase activities are significantly elevated in walls of peaches that have become wooly. Cellulase activities correlated well with increased level of the transcript, but differential expression of PGase did not correspond with the observed pattern of mRNA accumulation. When expression of ethylene biosynthesis related genes was followed no significant differences in ACC synthase gene expression was observed in the wooly fruit while the normal activation of the ACC oxidase was partially repressed in the Hermosa wooly fruits. Normal ripening-related loss of the uronic acid-rich polymers was stalled in the wooly Hermosa inconsistent with the observed elevation in a specific PGase activity but consistent with PG gene expression. In general, analysis of the level of total esterification, degree of methyl esterification and level of non-methyl esters did not reveal any major alterations between the different fruit varieties or between normal and abnormal ripening. Some decrease in the level of uronic acids methyl esterification was observed for both Hermosa and Sunsnow undergoing ripening following storage at low temperature but not in fruits ripening after harvest. Our results support a role for imbalanced cell wall degradation as a basis for the chilling disorder. While these results do not support a role for the imbalance between PG and pectin methyl esterase (PME) activities as the basis for the disorder they suggest a possible role for imbalance between cellulose and other cell wall polymer degradation during the softening process.
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