Search results for "Roca"
showing 10 items of 1893 documents
Frozen or dynamic? : An atomistic simulation perspective on the timescales of electrochemical reactions
2023
Electrochemical systems span a wide range of timescales, and several recent works have put forth the idea that the reaction environment should remain frozen and out of equilibrium during electrochemical electron or proton transfer reactions. Furthermore, simplified treatments of the electrochemical interface model the solvent and ions as frozen molecules. However, the claims and practices of a frozen environment strongly clash with most theoretical and simulation approaches developed to study electrochemical reaction rates. It has also been suggested that the electrode potential should not be fixed when simulating reaction rates due to conductivity limitations, which indicates constant pote…
Sexual selection on song and cuticular hydrocarbons in two distinct populations of Drosophila montana
2011
Sexual selection has the potential to contribute to population divergence and speciation. Most studies of sexual selection in Drosophila have concentrated on a single signaling modality, usually either courtship song or cuticular hydrocarbons (CHCs), which can act as contact pheromones. We have examined the relationship between both signal types and reproductive success using F1–3 offspring of wild- collected flies, raised in the lab. We used two populations of the Holarctic species Drosophila montana that represent different phylogeographic clades that have been separate for ca. 0.5 million years (MY), and differ to some extent in both traits. Here, we characterize the nature and identify …
Pyrolytic formation of polycyclic aromatic hydrocarbons from sesquiterpenes
2012
Author's version of an article in the journal: Food Chemistry. Also available from the publisher at: http://dx.doi.org/10.1016/j.foodchem.2012.06.033 The products of the pyrolysis of four sesquiterpenes, β-caryophyllene, α-cedrene, longifolene and valencene, have been examined. Pyrolysis was carried out at 300, 400 and 500 °C, the products determined by GC–MS and then examined for similarities and differences using multivariate data analysis. Analysis showed that longifolene was most resistant and caryophyllene least resistant to pyrolysis with cedrene and valencene occupying intermediate positions. While the compounds were largely unchanged at 300 °C, polycyclic aromatic hydrocarbons (PAHs…
Effects of ectopic expression of NGAL on doxorubicin sensitivity.
2012
Neutrophil gelatinase-associated lipocalin (NGAL, a.k.a Lnc2) is a member of the lipocalin family which has diverse roles including stabilizing matrix metalloproteinase-9 from auto-degradation and as siderocalins which are important in the transport of iron. NGAL also has important biological functions involved in immunity and inflammation as well as responses to kidney damage. NGAL expression has also been associated with certain neoplasia and is important in the metastasis of breast cancer. Many advanced cancer patients have elevated levels of NGAL in their urine and it has been proposed that NGAL may be a prognostic indicator for certain cancers (e.g. breast, brain, and others). NGAL exp…
Comparison of local electrochemical impedance measurements derived frombi-electrode and microcapillary techniques
2009
Abstract In the present paper, local electrochemical impedance spectra were obtained on a 316L stainless steel from two configurations: a dual microelectrode (bi-electrode) and microcapillaries. With the bi-electrode, the local impedance measurements were made from the ratio of the applied voltage to the local current density calculated from the application of the ohm's law. With the use of microelectrochemical cells, the specimen surface area in contact with the electrolyte is limited by the use of glass microcapillaries and the local impedance was defined from the ratio of the local potential to the local current restricted to the analysed surface area. Differences and similarities observ…
Constant inner potential DFT for modelling electrochemical systems under constant potential and bias
2021
Electrochemical interfaces and reactions play a decisive role in e.g. clean energy conversion but understanding their complex chemistry remains an outstanding challenge. Constant potential or grand canonical ensemble (GCE) simulations are indispensable for unraveling the properties of electrochemical processes as a function of the electrode potential. Currently, constant electrode potential calculations at the density functional theory (DFT) level are carried out by fixing the Fermi level of the simulation cell. However, the Fermi level from DFT calculations does does not always reflect the experimentally controlled electrode potential or describe the thermodynamic independent variable in G…
Reciprocal commitment in academic careers? : Finnish implications and international trends
2016
This study explores the nature of reciprocal commitment in academic careers. The article is based on a survey conducted in autumn 2013 among fixed-term employees at eight major universities in Finland (N = 810). The analysis is focusing on researchers who have a doctoral degree and who are working on a fixed-term contract at their university (n = 308). According to our study, researchers experience their working conditions are insecure and many of them have considered leaving their universities. Despite the fact that they find their work meaningful their uncertain and poor working conditions are related to their thoughts of leaving the university. In addition in many of the cases leaving th…
Decompressive Craniectomy Improves QTc Interval in Traumatic Brain Injury Patients
2020
Background: Traumatic brain injury (TBI) is commonly associated with cardiac dysfunction, which may be reflected by abnormal electrocardiograms (ECG) and/or contractility. TBI-related cardiac disorders depend on the type of cerebral injury, the region of brain damage and the severity of the intracranial hypertension. Decompressive craniectomy (DC) is commonly used to reduce intra-cranial hypertension (ICH). Although DC decreases ICH rapidly, its effect on ECG has not been systematically studied. The aim of this study was to analyze the changes in ECG in patients undergoing DC. Methods: Adult patients without previously known cardiac diseases treated for isolated TBI with DC were studied. EC…
La casa-fábrica de obrar azulejos de Vicente Pedrón y Josefa María Casavall en València (1686-1778)
2023
Las fábricas de azulejos en la ciudad de València del último cuarto del siglo XVII y principio del XVIII elaboraron una producción singular. La continuidad técnica facilitó la evolución estética consiguiendo colores y diseños innovadores de alto nivel cromático. Las noticias sobre la actividad de estos obradores, sus creaciones, y sus autores, no son abundantes y más cuando muchos edificios de la época en estudio repletos de azulejos, han ido desapareciendo con el tiempo. En esta ocasión, recurrimos a la información que proporcionan algunos pleitos generados en el entorno de dichas fábricas con el objetivo de identificar las características de las obras realizadas y los productos que generó…
LEAVES OFNERIUM OLEANDERL. AS BIOACCUMULATORS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAH) IN THE AIR OF PALERMO (ITALY): EXTRACTION AND GC-MS ANALYSIS,…
2005
Polycyclic Aromatic Hydrocarbons (PAH) were determined in the leaves of Nerium oleander L. an evergreen plant that occurs widely in both urban and rural areas, to monitor the degree of pollution in the urban area of Palermo (Italy) compared to remote areas. Twenty sites (urban roadside, urban, urban park, suburban and rural) in and around Palermo city were investigated. The purpose of this research was to investigate concentration levels and distribution patterns and relate them to possible sources. Analysis of 19 PAH was performed by gas chromatography/mass spectrometry (GCMS) using selected ion monitoring (SIM). The total amount of PAH ranged from 10 to 166 μg/Kg d.w. Each source gives ri…