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Capillary electrophoretic and extraction conditions for the analysis of Catha edulis FORKS active principles
2013
A capillary electrophoretic method, which allowed the detection and separation of the active principles of Catha edulis, i.e. cathinone, cathine and phenylpropanolamine, was developed. A suitable internal standard (nicotinamide), which permitted the quantification of the analytes reducing the variability of the migration times due to EOF changes, was identified. The analytical method was validated, assessing linearity, sensitivity and repeatability, showing optimal features for the analysis of the vegetable material. Moreover extraction conditions were investigated to achieve the exhaustion of the plant material in the fastest and most efficient way to meet the requirements of the Court.
Photocatalytic degradation of phenol in aqueous titanium dioxide dispersions
1988
The results of a study of photocatalytic degradation of phenol using aqueous oxygenated TiO2 (anatase) suspensions in a batch Pyrex photoreactor are reported. The influence on the photodegradation rate of various parameters as pH, phenol and TiO2 content, oxygen partial pressure, anions present in the dispersions was investigated. A complete oxidation of phenol was observed. Intermediate compounds, catechol and quinone, were detected. It was observed that the photodegradation also proceeded with sunlight radiation. A mechanistic and kinetic model, which accounts for the results obtained, is given. Likely reasons for inactivity of the rutile modification for this reaction are also given.
Hybrid TiO2 @ phthalocyanine catalysts in photooxidation of 4-nitrophenol: Effect of the matrix and sensitizer type
2020
Abstract Microcrystalline and nanocrystalline anatase (TiO2) based hybrid photocatalysts including selected phthalocyanine sensitizers were explored in photooxidation of 4-nitrophenol (4-NP) in water. Composites obtained with the homemade pure nano-anatase displayed a very poor catalytic performance compared to the other ones prepared from the commercial Tioxide-Huntsman (micro) and Evonik P25 (nano) products. In particular, the microcrystalline anatase impregnated with sandwich phthalocyanines of Gd or Yb showed excellent results both in photooxidation of 4-NP and hydroquinone, and proved the only ones which completely removed these two compounds from the system during the same reaction cy…
Effects of ACE-Inhibitors and Angiotensin Receptor Blockers on Inflammation
2011
The role of inflammation in cardiovascular disease and in hypertensive disease above all, is complex. Several studies confirm that activation of renin-angiotensin-aldosterone system (RAAS), through increase in the production of angiotensin II (Ang II), is closely related to local vascular inflammation. Over the BP lowering effects of anti-hypertensive treatments, several ancillary effects for every class may be found, distinguishing the various drugs from one another. Given the pro-inflammatory effects of Ang II and aldosterone, agents that interfere with the components of RAAS, such as ACE inhibitors, Angiotensin Receptor Blockers (ARBs), and mineralocorticoid receptor antagonists (spirono…
Influence of Proton Conducting Cations on the Structure and Properties of 2D Anilate-Based Magnets
2017
The syntheses, structures, magnetic, and proton conductivity properties of a family of bimetallic anilate-based compounds with inserted alkylammonium cations are presented. The structures of (Me2NH2)[MnIICrIII(Br2An)3]·2H2O (1), (Et2NH2)[MnIICrIII(Br2An)3] (2), (Et3NH)[MnIICrIII(Cl2An)3] (3), and [(Et)(i-Pr)2NH]-[MnIICrIII(Br2An)3]·(CHCl3)0.5·(H2O) (4) contain a 2D anionic network formed by Mn(II) and Cr(III) ions linked through anilate ligands. In 1, 2, and 3, the hexagonal holes of this network are occupied by Me2NH2+, Et2NH2+, or Et3NH+ cations. Interestingly, the small increase of size of the templating cation in 4 ([(Et)(i-Pr)2NH]+ in the place of Me2NH2+, Et2NH2+ or Et3NH+), gives ris…
Ring splitting of azetidin-2-ones via radical anions
2012
The radical anions of azetidin-2-ones, generated by UV-irradiation in the presence of triethylamine, undergo ring-splitting via N-C4 or C3-C4 bond breaking, leading to open-chain amides. This reactivity diverges from that found for the neutral excited states, which is characterised by alpha-cleavage. The preference for beta-cleavage is supported by DFT theoretical calculations on the energy barriers associated with the involved transition states. Thus, injection of one electron into the azetidin-2-one moiety constitutes a complementary activation strategy which may be exploited to produce new chemistry.
Detection of mitochondrial electron chain carrier redox status by transhepatic light intensity during rat liver reperfusion.
2003
The aim of the study was to investigate mitochondrial electron transfer during rat liver reperfusion after cold storage and hypothermic machine perfusion. Livers from male Brown Norway rats were preserved (UW) for 10h either by cold storage (CS) or by hypothermic oxygenated perfusion extracorporal (HOPE). Transhepatic photometric analysis allowed determination of the redox status of mitochondrial cytochromes during preservation, rewarming and reperfusion. Mitochondrial electron chain carriers were inhibited at different sites with rotenone and cyanide in some experiments. reversed transcriptional polymerase chain reaction (RT-PCR) was performed after reperfusion concerning transcription of …
Asymmetric Synthesis of Spiro-oxindole-ε-lactones through N-Heterocyclic Carbene Catalysis
2018
An unprecedented N-heterocyclic carbene-catalyzed annulation of isatin-derived enals and o-hydroxyphenyl-substituted p-quinone methides as bifunctional reagents has been discovered. The new protocol involves a 1,6-addition of the homoenolate equivalent intermediates to the hydroxy donor-1,6-Michael acceptors and leads to spirocyclic oxindole-ε-lactones in high yields and very good stereoselectivities.
Electrochemical synthesis of coenzymes Qn by oxidation of tetramethoxy precursors
2009
The electrochemical oxidation of tetramethoxy precursors (2) to coenzymes Q (n) (1) at a carbon anode was investigated both in a bench-scale batch electrochemical reactor and in a continuous recirculation reaction system equipped with a parallel-plate electrochemical divided cell. High faradic efficiency (> 60%) and excellent selectivity (> 90%) in coenzymes Q (n) were obtained in CH3CN or CH3CN/CH2Cl2 + 0.15 M Bu4NBF4 under potentiostatic or amperostatic alimentation.
Palladium-Catalysed Amination of 1,8- and 1,5-Dichloroanthracenes and 1,8- and 1,5-Dichloroanthraquinones
2005
Diamino derivatives of anthracene and anthraquinone have been synthesised by palladium-catalysed coupling of 1,8-dichloroanthracene and 1,8-dichloroanthraquinone with a wide range of aliphatic and aromatic primary and secondary amines. The use of polyamines gave rise to a large number of new nitrogen- and oxygen-containing macrocycles incorporating anthracene or anthraquinone moieties. The method has also been employed for the preparation of bismacrocycles in which two cyclam or azacrown units are linked together by an anthracene bridge through C(sp2)−N bonds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)