Martinez R.,University of La Rioja |
Paniagua M.,Autonomous University of Madrid |
Mayneris-Perxachs J.,University of Barcelona |
Mayneris-Perxachs J.,Avda University |
And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2017
The dynamics of the title reaction was studied using mainly the quasiclassical trajectory (QCT) method on the ground 12A′′ (OH+ channel) and first excited 12A′ (OH channel) potential energy surfaces (PESs) employing ab initio analytical representations of the PESs developed by us. Both PESs correspond to exoergic reactions, are barrierless and present a deep minimum along the minimum energy path (MEP). Some extra calculations (cross sections) were also performed with the time dependent quantum real wave packet method at the centrifugal sudden level (RWP-CS method). A broad set of properties as a function of collision energy (Ecol ≤ 0.5 eV) was considered using the QCT method: cross sections, average fractions of energy, product rovibrational distributions, two- and three-vector properties, and the microscopic mechanisms analyzing their influence on the dynamics. The proton transfer channel dominates the reactivity of the system and significant differences between the two reaction channels are found for the vibrational distributions and microscopic mechanisms. The results were interpreted according to the properties of the ground and excited PESs. Moreover, the QCT and RWP-CS cross sections are in rather good agreement for both reaction channels. We hope that this study will encourage the experimentalists to investigate the dynamics of this interesting but scarcely studied system, whose two lowest PESs include the ground and first excited electronic states of the H2O+ cation. © the Owner Societies 2017.
Quinones M.,Rovira i Virgili University |
Guerrero L.,Rovira i Virgili University |
Guerrero L.,ALPINA S.A |
Fernandez-Vallinas S.,Complutense University of Madrid |
And 7 more authors.
Journal of Functional Foods | Year: 2014
The aim of this study was to evaluate the involvement of endothelial-relaxing factors as possible antihypertensive mechanism of low-molecular-weight procyanidin rich grape seed extract (LM-GSPE). Thirty 17-20-week-old male spontaneously hypertensive rats (SHR) were administered water or 375. mg/kg LM-GSPE by intragastric gavage. One millilitre of saline, 30. mg/kg NG-Nitro-l-arginine methyl ester (l-NAME) or 5. mg/kg indomethacin was administrated intraperitoneally. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded before and 6. h after oral administration. Plasma concentration of 6-keto-prostaglandin F1α (PGF1α) was quantified. In addition, we evaluated the relaxation caused by LM-GSPE in different aorta preparations. The antihypertensive effect of LM-GSPE was completely and partially abolished by l-NAME and indomethacin, respectively. In addition, plasma PGF1α was increased in LM-GSPE-administered rats. Finally, LM-GSPE relaxed the intact aorta preparations but did not relax the endothelium-denuded aorta rings. l-NAME inhibited the relaxation caused by LM-GSPE in the SHR aorta rings, but indomethacin did not. Therefore, the antihypertensive effect of LM-GSPE in SHR is endothelium dependent, and it could be mediated by changes in endothelium-derived nitric oxide bioavailability. Nevertheless, prostacyclin could also contribute additionally to this effect. © 2013 Elsevier Ltd.
Kim H.,Gyeongsang National University |
Dwyer L.,University of Nevada, Reno |
Song J.H.,Inha University |
Martin-Cano F.E.,Avda University |
And 5 more authors.
Neurogastroenterology and Motility | Year: 2011
Background Inflammatory responses can include recruitment of cells of hematopoietic origin to the tunica muscularis. These cells can secrete a variety of factors which can reset the gain of smooth muscle cells (SMC) and influence motor patterns. Histamine (H), a major mediator in inflammation, is released by mast cells and exerts diverse effects in SMC by binding to H receptors. The profiles of H receptor expression in animal models used to study inflammatory diseases are unknown. Methods Histamine receptor expression and electro-mechanical responses to H were tested in simian and murine colonic smooth muscle using qualitative and quantitative PCR, isometric force measurements, microelectrode recordings and patch clamp techniques. Key Results H1, H2, and H4 receptor transcripts were expressed at similar levels in simian colonic tissue whereas only the H2 receptor transcript was detected in murine colonic tissue. Stimulation of simian colonic muscles with H caused depolarization and contraction in the presence of tetrodotoxin. Histamine activated non-selective cation channels in simian SMC. In contrast, H caused hyperpolarization and inhibited contractions of murine colon. The hyperpolarization was inhibited by the K ATP channel blocker, glibenclamide. Histamine-activated K + currents were inhibited by glibenclamide in murine colonic SMC. Conclusions & Inferences Histamine receptor expression in simian SMC was similar to that reported in humans. However, H receptor profile and responses to H were considerably different in mice. Thus, monkey colon may be a more suitable model to study how inflammatory mediators affect the gain of smooth muscle excitability. © 2011 Blackwell Publishing Ltd.
Jordi C.,Rovira i Virgili University |
Manjon M.,Rovira i Virgili University |
Manjon M.,Avda University
The Annals of Regional Science | Year: 2014
This paper analyses the determinants of employment and unemployment spells in an urban area. Using data from a random sample of labour force participants in Barcelona, we find that individual, firm, regulatory and macroeconomic factors all affect urban (un)employment duration to a certain degree. Also, national and urban (un)employment exhibits the same shape in the baseline hazards and has similar macroeconomic and regulatory drivers, being the individuals' characteristics the main source of difference we can identify. Consistent with the matching theory, the predicted hazards indicate that the likelihood of finding a job and of being fired is higher and lower, respectively, in the city of Barcelona than in an average Spanish location. © 2014 Springer-Verlag Berlin Heidelberg.