1,721,104 research outputs found
E-cigarettes induce toxicological effects that can raise the cancer risk. The contribute of EPR radical trapping technique
No full textE-cigarettes induce toxicological effects that can raise the cancer
risk. The contribute of EPR radical probe technique
Donatella Canistro1, Fabio Vivarelli1, Silvia Cirillo1, Andrea Sapone1, Moreno Paolini1,
Paola Franchi2, Marco Lucarini2
1Department of Pharmacy and Biotechnology (University of Bologna, Via Irnerio 48, I-40126 Bologna, Italy)
2Department of Chemistry “G. Ciamician” (University of Bologna, Via San Giacomo 11, I-40126 Bologna, Italy)
E-mail: [email protected]
Electronic cigarettes (e-cigs) are devices designed to deliver nicotine in a vaping solution rather than smoke and without tobacco combustion. Perceived as a safer alternative to conventional cigarettes, e-cigs are aggressively marketed as lifestyle-choice consumables, thanks to few restrictions and a lack of regulatory guidelines. Despite the burgeoning worldwide consumption of e-cigs, their safety remains largely unproven and it is unknown whether these devices cause in vivo toxicological effects
that could contribute to cancer. Here we illustrate the contribute of EPR radical probe technique in a study where it was possible to demonstrate the co-mutagenic and cancer-initiating effects of e-cig vapour in a rat lung model. It was found that e-cig have a powerful booster effect on phase-I carcinogen-bioactivating enzymes, and increase oxygen free radical production and DNA oxidation.
We are able to indirectly evaluate the content of reactive oxygen species (ROS) in lungs tissues of exposed rats, by using an appropriate hydroxylamine that in the presence of transient radical species gives rise to a persistent nitroxide radical. (see Scheme 1)
Scheme 1
We found a significant increase of radical species production in samples of lungs tissues from exposed rats compared to samples from non-exposed animals.
[1] Canistro, D.; Vivarelli, F.; Cirillo, S.; Babot Marquillas, C.; Buschini, A.; Lazzaretti, M.;Marchi, L.; Cardenia, V.; Rodriguez-Estrada, M.T.; Lodovici, M.; Cipriani, C.; Lorenzini, A.; Croco, E.; Marchionni, S.; Franchi, P.; Lucarini, M.; Longo, V.; Della Croce, C.M.; Vornoli, A.; Colacci, A.; Vaccari, M.; Sapone, A.; Paolini, M. SCIENTIFIC REPORTS. 2017, DOI:10.1038/s41598-017-02317-8
[2] Vivarelli, F.; Canistro, D.; Franchi, P.; Sapone, A.; Vornoli, A.; Della Croce, C.; Lucarini, M.; Paolini, M. Life Sciences, 2016, 145, 166-173. DOI:10.1016/j.lfs.2015.12.033
[3] Fabbri, R.; Sapone, A.; Paolini, M.; Vivarelli, F.; Franchi, P.; Lucarini, M.; Pasquinelli, G.; Vicenti, R.; Macciocca, M.; Venturoli, S.; Canistro, D. Hystology and Hystopatology, 2015, 30, 725-730 DOI: 10.14670/HH-30.72
Do Peroxyl Radicals Obey the Principle That Kinetic Solvent Effects on H-Atom Abstraction Are Independent of the Nature of the Abstracting Radical?
No full textNot availabl
Homolytic reactivity of ligated boranes toward alkyl, alkoxyl, and peroxyl radicals
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A method to differentiate the causes of stiff-knee gait (skg) in stroke patients with hemiplegia
No full textSKG is frequent in patients with hemiplegia due to stroke. The lack of knee flexion lead to the use of compensatory mechanisms at the hip and the pelvis and determines a huge increase in the energetic cost of gait [1]. In the literature, SKG has been mainly associated to an overactivity of the quadriceps muscles, while more recently it has been also related to the limited knee flexion velocity in pre-swing due to the lack of push-off [2,3]. In this study, we propose a method to separate, among the causes of SKG, the lack of push-off from the presence of braking mechanisms due to the stretch-induced overactivity of the thigh muscles
Aerobic oxidation of benzyl alcohols catalyzed by aryl substituted N-hydroxyphthalimides. Possible involvement of a charge-transfer complex
No full textA series of aryl-substituted N-hydroxyphthalimides (X-NHPIs) containing either electron-withdrawing groups (4-CH(3)OCO, 3-F) or electron-donating groups (4-CH(3), 4-CH(3)O, 3-CH(3)O, 3,6-(CH(3)O)(2)) have been used as catalysts in the aerobic oxidation of primary and secondary benzylic alcohols. The selective formation of aromatic aldehydes was observed in the oxidation of primary alcohols; aromatic ketones were the exclusive products in the oxidation of secondary alcohols. O-H bond dissociation enthalpies (BDEs) of X-NHPIs have been determined by using the EPR radical equilibration technique. BDEs increase with increasing the electron-withdrawing properties of the aryl substituent. Kinetic isotope effect studies and the increase of the substrate oxidation rate by increasing the electron-withdrawing power of the NHPI aryl substituent indicate a rate-determining benzylic hydrogen atom transfer (HAT) from the alcohol to the aryl-substituted phthalimide-N-oxyl radical (X-PINO). Besides enthalpic effects, polar effects also play a role in the HAT process, as shown by the negative rho values of the Hammett correlation with sigma(+) and by the decrease of the rho values (from -0.54 to -0.70) by increasing the electron-withdrawing properties of the NHPI aryl substituent. The relative reactivity of 3-CH(3)O-C(6)H(4)CH(2)OH and 3,4-(CH(3)O)(2)-C(6)H(3)CH(2)OH, which is higher than expected on the basis of the sigma(+) values, the small values of relative reactivity of primary vs secondary benzylic alcohols, and the decrease of the rho values by increasing the electron-withdrawing properties of the NHPI aryl substituent, suggest that the HAT process takes place inside a charge-transfer (CT) complex formed by the X-PINO and the benzylic alcohol
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