Suchergebnisse

Phenols are regarded as highly toxic chemicals. Their effects are difficult to study in in vitro systems because of their ambiguous fate (degradation, auto-oxidation and volatility). In the course of in vitro studies of a series of redox-cycling phenols, we found evidences of cross-contamination in several in vitro high-throughput test systems, in particular by trimethylbenzene-1, 4-diol/trimethylhydroquinone (TMHQ) and 2,6-di-tertbutyl-4-ethylphenol (DTBEP), and investigated in detail the physicochemical basis for such phenomenon and how to prevent it. TMHQ has fast degradation kinetics followed by significant diffusion rates of the resulting quinone to adjacent wells, other degradation products being able to air-diffuse as well. DTBEP showed lower degradation kinetics, but a higher diffusion rate. In both cases the in vitro toxicity was underestimated because of a decrease in concentration, in addition to cross-contamination to neighbouring wells. We identified four degradation products for TMHQ and five for DTBEP indicating that the current effects measured on cells are not only attributable to the parent phenolic compound. To overcome these drawbacks, we investigated in detail the physicochemical changes occurring in the course of the incubation and made use of gas-permeable and non-permeable plastic seals to prevent it. Diffusion was greatly prevented by the use of both plastic seals, as revealed by GC–MS analysis. Gas non-permeable plastic seals, reduced to a minimum compounds diffusion as well oxidation and did not affect the biological performance of cultured cells. Hence, no toxicological cross-contamination was observed in neighbouring wells, thus allowing a more reliable in vitro assessment of phenol-induced toxicity. ; The authors wish to acknowledge the support of the European Union's Horizon 2020 research and innovation 493 program under Grant Agreement No 681002 (EU-ToxRisk). We are indebted to CIBEREHD (ISCIII), for supporting our research program on hepatotoxicity of xenobiotics. L.T. was ...

Diets rich in (poly)phenols are associated with a reduced reduction in the incidence of cardiovascular disorders. While the absorption and metabolism of (poly)phenols has been described, it is not clear how their metabolic fate is affected under pathological conditions. This study evaluated the metabolic fate of berry (poly)phenols in an in vivo model of hypertension as well as the associated microbiota response. Dahl salt-sensitive rats were fed either a low-salt diet (0.26% NaCl) or a high-salt diet (8% NaCl), with or without a berry mixture (blueberries, blackberries, raspberries, Portuguese crowberry and strawberry tree fruit) for 9 weeks. The saltenriched diet promoted an increase in the urinary excretion of berry (poly)phenol metabolites, while the abundance of these metabolites decreased in faeces, as revealed by UPLC¿MS/MS. Moreover, salt and berries modulated gut microbiota composition as demonstrated by 16S rRNA analysis. Some changes in the microbiota composition were associated with the high-salt diet and revealed an expansion of the families Proteobacteria and Erysipelotrichaceae. However, this effect was mitigated by the dietary supplementation with berries. Alterations in the metabolic fate of (poly)phenols occur in parallel with the modulation of gut microbiota in hypertensive rats. Thus, beneficial effects of (poly)phenols could be related with these interlinked modifications, between metabolites and microbiota environments. ; C.B., C.N.d.S., C.O. were funded by ANR (ANR-13-ISV1-0001-01) and FCT (FCTANR/BEX-BCM/0001/2013). D.B. was funded by the Austrian Science Fund (FWF P26127-B20) and European Research Council (Starting Grant: FunKeyGut 741623). D.S. and A.F. acknowledge support from Scottish Government: Rural and Environment Science and Analytical Services. We also acknowledge the Investment for the Future program ANR-11-IDEX-0003-01 within the LABEX ANR-10-LABX-0033 (C.B., C.O.), Fundação para a Ciência e Tecnologia financial support of A.G. (SFRH/BD/103155/2014) and C.N.d.S. (IF/01097/2013). iNOVA4Health Research Unit (LISBOA-01-0145-FEDER-007344), which is cofounded by FCT through national funds, and by FEDER under the PT2020 Partnership Agreement, is acknowledged.

Diets rich in (poly)phenols are associated with a reduced reduction in the incidence of cardiovascular disorders. While the absorption and metabolism of (poly)phenols has been described, it is not clear how their metabolic fate is affected under pathological conditions. This study evaluated the metabolic fate of berry (poly)phenols in an in vivo model of hypertension as well as the associated microbiota response. Dahl salt-sensitive rats were fed either a low-salt diet (0.26% NaCl) or a high-salt diet (8% NaCl), with or without a berry mixture (blueberries, blackberries, raspberries, Portuguese crowberry and strawberry tree fruit) for 9 weeks. The salt-enriched diet promoted an increase in the urinary excretion of berry (poly)phenol metabolites, while the abundance of these metabolites decreased in faeces, as revealed by UPLC–MS/MS. Moreover, salt and berries modulated gut microbiota composition as demonstrated by 16S rRNA analysis. Some changes in the microbiota composition were associated with the high-salt diet and revealed an expansion of the families Proteobacteria and Erysipelotrichaceae. However, this effect was mitigated by the dietary supplementation with berries. Alterations in the metabolic fate of (poly)phenols occur in parallel with the modulation of gut microbiota in hypertensive rats. Thus, beneficial effects of (poly)phenols could be related with these interlinked modifications, between metabolites and microbiota environments. ; C.B., C.N.d.S., C.O. were funded by ANR (ANR-13-ISV1-0001-01) and FCT (FCTANR/BEX-BCM/0001/2013). D.B. was funded by the Austrian Science Fund (FWF P26127-B20) and European Research Council (Starting Grant: FunKeyGut 741623). D.S. and A.F. acknowledge support from Scottish Government: Rural and Environment Science and Analytical Services. We also acknowledge the Investment for the Future program ANR-11-IDEX-0003-01 within the LABEX ANR-10-LABX-0033 (C.B., C.O.), Fundação para a Ciência e Tecnologia financial support of A.G. (SFRH/BD/103155/2014) and C.N.d.S. (IF/01097/2013). iNOVA4Health Research Unit (LISBOA-01-0145-FEDER-007344), which is cofounded by FCT through national funds, and by FEDER under the PT2020 Partnership Agreement, is acknowledged.

Abstract
N-doped ZnO beads (NZB) and N-doped TiO2 beads (NTB) were synthesized via a modified sol–gel technique utilizing chitosan (CS)/polyvinyl alcohol (PVA) hydrogel beads as basic support for photocatalyst. Urea was used as a source of nitrogen in the preparation of N-doped ZnO beads, while ammonium acetate, CH3COONH4, was used as a nitrogen source in the production of N-doped TiO2 beads. The characteristics of synthesized beads were identified by scanning electron microscope (SEM), X-ray photoelectron spectroscopy analysis (XPS), X-ray diffraction (XRD), N2 adsorption–desorption isotherms, BET surface area, Fourier transform infrared (FT-IR) measurements, and diffuse reflectance spectroscopy (DRS) studies. The use of the nitrogen doping method for photocatalyst was performed to adjust the bandgap and electrical properties of ZnO and TiO2 by establishing acceptor defects. NZB and NTB with the intrinsic donor defect of oxygen vacancy and the nitrogen-to-oxygen acceptor defect could be activated by a less-energy UV consumption for efficient pollutant degradation. The results indicated that the as-synthesized NZB achieved much higher degradation activity than NTB, commercial ZnO, and TiO2 in the decomposition of a binary mixture composed of ammonia and phenol under UV light irradiation.

2-(5-Bromo-1H-benzimidazol-2-yl)-3'/4'/5'-substituted-phenols (HL1 – HL25) were synthesized and characterized using various spectroscopic techniques. Then, Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ru(III) complexes of 2-(5-bromo-1H-benzimidazol-2-yl)phenol (HL1) were prepared and the methods such as elemental analysis, thermogravimetric analysis (TGA), molar conductivity and magnetic moment measurements, FT-IR, fluorescence and NMR spectroscopy were used to make suggestions about structures of the complexes. It is interesting that the compounds HL12 and HL22 showed stronger fluorescence effects than the others. The common feature of these two compounds is that they have a fluorine substituent at the 4'-position on the phenol ring. In addition, antioxidant and antibacterial activity of the compounds were investigated. The first three compounds showing the best antioxidant activity are HL25 (trihydroxy derivative: 4-(5-bromo-1H-benzimidazol-2-yl)benzene-1,2,3-triol), HL8 (2,5-dihydroxy derivative) and HL6 (2,3-dihydroxy derivative). It was observed that HL25 showed higher antioxidant activity than the reference substances 3,5-di-tert-4-butylhydroxytoluene (BHT) and Trolox both in terms of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging (0.0018 mg/mL) and ferric reducing / antioxidant power (FRAP) methods {trolox equivalent antioxidant capacity (TEAC) value: 1564.44±1.92}. The second and third hydroxy groups added to HL1 appear to significantly increase the antioxidant activity. It was determined that complexes of HL1 showed much better antioxidant effect with respect to HL1. The derivatives with the highest antibacterial effect were found to be HL14 (nitro derivative), HL8, HL6 and HL25 having moderate activity. The high levels of both antioxidant and antibacterial activities of HL6, HL8 and HL25 indicate a correlation between their antibacterial and antioxidant effects. It was observed that the Ru(III) and Co(II) complexes showed moderate antibacterial activity whereas the ligand was inactive.

1 Methods of Plant Analysis -- 1.1 Introduction -- 1.2 Methods of extraction and isolation -- 1.3 Methods of separation -- 1.4 Methods of identification -- 1.5 Analysis of results -- 1.6 Applications -- 2 Phenolic Compounds -- 2.1 Introduction -- 2.2 Phenols and phenolic acids -- 2.3 Phenylpropanoids -- 2.4 Flavonoid pigments -- 2.5 Anthocyanins -- 2.6 Flavonols and flavones -- 2.7 Minor flavonoids, xanthones and stilbenes -- 2.8 Tannins -- 2.9 Quinone pigments -- 3 The Terpenoids -- 3.1 Introduction -- 3.2 Essential oils -- 3.3 Diterpenoids and gibberellins -- 3.4 Triterpenoids and steroids -- 3.5 Carotenoids -- 4 Organic Acids, Lipids and Related Compounds -- 4.1 Plant acids -- 4.2 Fatty acids and lipids -- 4.3 Alkanes and related hydrocarbons -- 4.4 Polyacetylenes -- 4.5 Sulphur compounds -- 5 Nitrogen Compounds -- 5.1 Introduction -- 5.2 Amino acids -- 5.3 Amines -- 5.4 Alkaloids -- 5.5 Cyanogenic glycosides -- 5.6 Indoles -- 5.7 Purines, pyrimidines and cytokinins -- 5.8 Chlorophylls -- 6 Sugars and their Derivatives -- 6.1 Introduction -- 6.2 Monosaccharides -- 6.3 Oligosaccharides -- 6.4 Sugar alcohols and cyclitols -- 7 Macromolecules -- 7.1 Introduction -- 7.2 Nucleic acids -- 7.3 Proteins -- 7.4 Polysaccharides.

Front Cover -- Determination of Toxic Organic Chemicals In Natural Waters, Sediments and Soils -- Copyright Page -- Contents -- Preface -- 1 Hydrocarbons in nonsaline waters -- 1.1 Aliphatic hydrocarbons -- Head space analysis -- Gas stripping methods -- Gas chromatography -- High-performance liquid chromatography -- Infrared spectroscopy -- Thin-layer chromatography -- Fluorescence techniques -- Paper chromatography -- Sampling -- Oil spillages -- Metals in spillage oils -- Continuous monitoring of oil slicks -- 1.2 Aromatic hydrocarbons -- Gas chromatography -- Column chromatography -- Spectrophotometric method -- Infrared spectrometry -- Ultraviolet spectroscopy -- Polycyclic aromatic hydrocarbons -- Gas chromatography -- High-performance liquid chromatography -- Thin-layer chromatography -- Fluorescence spectrometry -- Miscellaneous -- References -- 2 Oxygen-containing compounds in nonsaline waters -- 2.1 Carboxylic acids -- Gas chromatography -- High-performance liquid chromatography -- Thin-layer chromatography -- Spectrophotometric methods -- Fluorescence spectrometry -- Potentiometry -- Polarography -- Miscellaneous -- 2.2 Phenols -- Gas chromatography -- High-performance liquid chromatography -- Thin-layer chromatography -- Raman spectroscopy -- Spectrophotometric method -- Atomic absorption spectroscopy -- Miscellaneous -- Preconcentration -- Preconcentration on 5-vinyl pyridine-divinylbenzene copolymer resin -- Preconcentration on silica gel-modified cellulose -- Preconcentration on N-vinyl-2-pyrrolidone copolymer -- Preconcentration on cation-exchange resins -- 2.3 Phenolic acids -- 2.4 Methyl tert-butyl ether -- 2.5 Alcohols -- Spectrophotometric methods -- Gas chromatography -- 2.6 Glycols -- Spectrometry -- Gas chromatography -- Thin-layer chromatography -- 2.7 Dioxans -- Gas chromatography -- 2.8 Esters -- Gas chromatography.

2-[4,6-{Dichloro/dimethyl/bis-(trifluoromethyl)}-benzimidazol-2-yl]-(5-bromo/methoxy)-phenols (HL1 – HL6) and their complexes with ZnCl2, PdCl2 and AuCl3 were synthesized and characterized. The structures of the complexes were confirmed on the basis of elemental analysis, molar conductivity, FT-IR, NMR and fluorescence spectroscopy. Most of the complexes are four-coordinated with a 1:2 M:L ratio and the Au(III) complexes are 1:1 electrolyte whereas the others are non-electrolyte. According to the fluorescence spectra, electronegative substituents such as bromo, chloro, trifluoromethyl and methoxy were found to increase red shift (shifting to higher wavelength). The highest wavelength was observed to belong to HL6 (trifluoromethyl-methoxy derivative) with 531 nm. When compared to the ligands, there is decreasing in the red shift and fluorescence intensity in the spectra of the complexes. In addition, antimicrobial activity of the compounds was evaluated against six bacteria and three fungi. The Au(III) complexes have superior activity against all the bacteria, while the Pd(II) complexes showed higher antifungal activity than the ligands and metal salt.

Paper submitted to the 7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013), New Delhi, India, 23-26 October 2013. ; A kinetic study has been carried out by thermogravimetry in order to compare the thermal behavior of printed circuit boards of mobile phones before and after the removal of the metallic fraction. Experiments were performed in nitrogen atmosphere (pyrolysis runs) as well as in an oxidative atmosphere (10% and 20% oxygen in nitrogen). Several dynamic and dynamic + isothermal runs have been carried out at different heating rates (5, 10 and 20 K min−1), from room temperature to more than 900 K. Moreover, TG–MS experiments were performed (in inert and oxidizing atmosphere) in order to better understand the thermal decomposition of these wastes. Different reaction models are proposed, one for pyrolysis and one for combustion of the two kinds of wastes studied, which proved to simulate appropriately the experimental results at all the heating rates simultaneously. Regarding the analysis of pollutants evolved, pyrolysis and combustion runs have been carried out at 600 ºC and 850 ºC in a horizontal laboratory furnace in order to analyze a wide range of gases, hydrogen halides, carbon oxides, light hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), chlorinated phenols (ClPhs), chlorinated benzenes (ClBzs) and brominated phenols (BrPhs), among others. Furthermore, polybromo- and polychloro-dibenzo-p-dioxins and furans (PBDD/Fs and PCDD/Fs) and dioxin-like polychlorobiphenyls (PCBs) are being analyzed. ; Ministry of Education and Science (Spain) (CTQ2008-05520 project) and Valencian Community Government (Spain) (PROMETEO/2009/043/FEDER project).

Conditions were established for the separation and analysis of Bisphenol A (BPA), Bisphenol F (BPF), and their diglycidyl ethers, by micellar electrokinetic capillary chromatography (MECC). Good resolution was obtained for all compounds, although in order to achieve the separation of ortho-ortho, ortho-para, and para-para isomers of Bisphenol F diglycidyl ether (BFDGE), BFDGE¿2H2O and BFDGE¿2HCl, it was necessary to use a 25 µm I.D. fused-silica capillary. To increase sensitivity, a field amplified sample injection (FASI)-MECC method was developed using 10 mM sodium dodecyl sulfate (SDS) solution as injection matrix and a 75 µm I.D. fused-silica capillary. Instrumental quality parameters such as limits of detection (0.999), and run-to-run and day-to-day precisions (relative standard deviations (RSD) values lower than 12.5%) were determined. Finally, the suitability of the FASI-MECC method for the analysis of BPA, BPF and their diglycidyl ethers in canned soft-drinks was evaluated. Quantitation was performed by matrix-matched calibration using a plastic-bottled isotonic drink as matrix. The results showed that FASI-MECC is an economic method for the screening and quantitation of these kinds of compounds in soft-drink beverages, with no loss of reproducibility, and effective at concentrations lower than the specific migration level (SML) values established by the European Union.

Phenolic compounds (benzoic and cinnamic acid derivatives) were determined by high-performance liquid chromatography with multiple wavelength detector (HPLC--MWD) in grape marc distillates aged in Quercus petraea, Quercus robur and Quercus alba wooden barrels. In addition to colour indices and evaluable polyphenols, all samples were described by sensorial analysis. There were significant differences in the mean concentrations of the majority of phenolic compounds among the samples. Gallic and benzoic acids were the most abundant and samples aged in Q. robur from Galicia (NW of Spain) had the highest concentration of most of the determined phenols. Grape marc distillates aged in Q. robur obtained the highest values of all sensorial attributes, whereas samples aged in Q. petraea and Q. alba obtained similar scores. Principal component analysis accounted for 88.32 % of total variance, showing a good separation of aged distillates in terms of phenolic compounds and colour characteristics, according to the species and origin of the oak wood used in the ageing process. ; We are grateful for the financial support of this work to the Spanish Ministry of Science and Innovation (project CTQ2011-28967), and partial financial support from the FEDER funds of the European Union and to the Regulatory Board of Geographical Names of the Traditional Galician Spirits and Liqueurs for providing the samples. Jose Manuel Salgado is grateful for postdoctoral fellowship (EX-2010-0402) of Education Ministry of Spanish ...

AbstractPhotoresist materials are indispensable in photolithography, a process used in semiconductor fabrication. The work process and potential hazards in semiconductor production have raised concerns as to adverse health effects. We therefore performed a health risk assessment of occupational exposure to positive photoresists in a single optoelectronic semiconductor factory in Taiwan. Positive photoresists are widely used in the optoelectronic semiconductor industry for photolithography. Occupational exposure was estimated using the Stoffenmanager® model. Bayesian modeling incorporated available personal air sampling data. We examined the composition and by‐products of the photoresists according to descriptions published in the literature and patents; the main compositions assessed were propylene glycol methyl ether acetate (PGMEA), novolac resin, photoactive compound, phenol, cresol, benzene, toluene, and xylene. Reference concentrations for each compound were reassessed and updated if necessary. Calculated hazard quotients were greater than 1 for benzene, phenol, xylene, and PGMEA, indicating that they have the potential for exposures that exceed reference levels. The information from our health risk assessment suggests that benzene and phenol have a higher level of risk than is currently acknowledged. Undertaking our form of risk assessment in the workplace design phase could identify compounds of major concern, allow for the early implementation of control measures and monitoring strategies, and thereby reduce the level of exposure to health risks that workers face throughout their career.