2,868 research outputs found
Assessment of DNA Damage by Comet Assay in Buccal Epithelial Cells: Problems, Achievement, Perspectives
DNA damage risk assessment in comet assay by the use of buccal mucosa cells has great advantages in comparison with other cell type sample due to more safely, easier, cheaper, and non-invasive method for in vivo studies. According to the OECD Guidelines, the in vivo mammalian alkaline comet assay is well-established and validated method for measuring DNA strand breaks in single eukaryotic cells. Considering exposure to xenobiotics and endogenous damage inductors, buccal mucosa cells are the first to be in direct contact after exposure and this makes them an ideal biomatrices in evaluation of the level of individual genotoxicity to several compounds already mentioned. Their clinical diagnostic applicability confers a potential use in patients across time. However, the number of publications referring to the human buccal comet assay is low in the last two decades. This low growing interest may be explained by several factors, including its relative technical problems. Different procedures have been used in collecting and processing the samples. In order to have widespread acceptance and credibility in human population studies, the comet assay in buccal cells requires standardization of the protocol, of parameters analyzed, and a better knowledge of critical features affecting the assay outcomes, including the definition of the values of spontaneous DNA damage. There is a need for further collaborative work as in the HUMN (micronucleus assay on lymphocytes) and HUMNxL (micronucleus assay on buccal cells) collaborative projects. The creation of a network of laboratories will allow more focused validation studies, including the design of a classic, historic, prospective cohort study in order to explore the link between measures of genetic instability in the buccal mucosa and the risk of cancer and other chronic-degenerative diseases. One such network connection will start in 2016 as a COST project under the name âhCOMETâThe comet assay as a human biomonitoring toolâ launched by Prof. Andrew Collins
Especies de caza: procesos de extinciĂłn ocultos tras elevados tamaĂąos de censo
Management of game species may involve a risk of alteration of their genetic properties. Local adaptations may be disrupted if artificially selected individuals from farms or those belonging to distant geographical areas are introduced to increase population density or trophy âqualityâ. In Spain, red deer (Cervus elaphus) from different European subspecies have been introduced to increase the size of trophies (antlers) of local populations. Legislation against these introductions is not effective for various reasons, and once the individuals are in the Iberian peninsula it is virtually impossible to prevent their spreading throughout the whole territory without a genetic tool to distinguish between autochthonous and foreign specimens. We have developed such a genetic test and propose a strategy to dissuade landâowners from importing foreign deer. Since deer are bred mainly for their antlers, our strategy is based on an agreement with the National Trophy Body in Spain which rejects trophies from foreign populations. Rejection decreases the value of the trophy so that it becomes more profitable to produce autochthonous deer. Using such a strategy at some critical step in the production or commercialization process may be a good model to apply in protecting genetic properties of exploited species.La gestiĂłn de las especies de caza puede conllevar riesgos de alteraciĂłn de sus propiedades genĂŠticas. Las adaptaciones locales pueden deteriorarse si ejemplares producidos mediante selecciĂłn artificial en granjas o procedentes de ĂĄreas geogrĂĄficas distantes, son introducidos para aumentar la densidad poblacional o la "calidad" de los trofeos de caza. En EspaĂąa, se han introducido ejemplares de ciervo ibĂŠrico (Cervus elaphus) procedentes de distintas subespecies europeas para aumentar asĂ el tamaĂąo de las cuernas (trofeos de caza) de las poblaciones autĂłctonas. La legislaciĂłn contra este tipo de introducciones no es eficaz por diversos motivos y, una vez introducidos los ejemplares en la penĂnsula ibĂŠrica, es prĂĄcticamente imposible prevenir su dispersiĂłn por todo el territorio sin contar con herramientas genĂŠticas que permitan diferenciar los ejemplares autĂłctonos de los forĂĄneos. Nosotros hemos desarrollado un test genĂŠtico para este fin, y hemos propuesto una estrategia para disuadir a lospropietarios de llevar a cabo la importaciĂłn de ejemplares forĂĄneos. Puesto que los ciervos se crĂan fundamentalmente por su cornamenta como trofeo de caza, nuestra estrategia se ha basado en un acuerdo con la Junta Nacional de HomologaciĂłn de Trofeos de Caza, para que ĂŠsta rechace los trofeos pertenecientes a ejemplares forĂĄneos. Este rechazo reduce el valor de los ejemplares procedentes de otras poblaciones y favorece la producciĂłn de ciervo autĂłctono. Sugerimos que la utilizaciĂłn de estrategias de este tipo en puntos clave de procesos de producciĂłn o comercializaciĂłn, puede ser un buen modelo a aplicar para proteger las propiedades genĂŠticas de las especies sujetas a explotaciĂłn por el hombre
Game species: extinction hidden by census numbers
Management of game species may involve a risk of alteration of their genetic properties. Local adaptations may be disrupted if artificially selected individuals from farms or those belonging to distant geographical areas are introduced to increase population density or trophy âqualityâ. In Spain, red deer (Cervus elaphus) from different European subspecies have been introduced to increase the size of trophies (antlers) of local populations. Legislation against these introductions is not effective for various reasons, and once the individuals are in the Iberian peninsula it is virtually impossible to prevent their spreading throughout the whole territory without a genetic tool to distinguish between autochthonous and foreign specimens. We have developed such a genetic test and propose a strategy to dissuade land-owners from importing foreign deer. Since deer are bred mainly for their antlers, our strategy is based on an agreement with the National Trophy Body in Spain which rejects trophies from foreign populations. Rejection decreases the value of the trophy so that it becomes more profitable to produce autochthonous deer. Using such a strategy at some critical step in the production or commercialisation process may be a good model to apply in protecting genetic properties of exploited species
Optical Gas Sensing of Ammonia and Amines Based on Protonated Porphyrin/TiO2 Composite Thin Films
Open porous and transparent microcolumnar structures of TiO2 prepared by physical vapour deposition in glancing angle configuration (GLAD-PVD) have been used as host matrices for two different fluorescent cationic porphyrins, 5-(N-methyl 4-pyridyl)-10,15,20-triphenyl porphine chloride (MMPyP) and meso-tetra (N-methyl 4-pyridyl) porphine tetrachloride (TMPyP). The porphyrins have been anchored by electrostatic interactions to the microcolumns by self-assembly through the dip-coating method. These porphyrin/TiO2 composites have been used as gas sensors for ammonia and amines through previous protonation of the porphyrin with HCl followed by subsequent exposure to the basic analyte. UVâvis absorption, emission, and time-resolved spectroscopies have been used to confirm the protonationâdeprotonation of the two porphyrins and to follow their spectral changes in the presence of the analytes. The monocationic porphyrin has been found to be more sensible (up to 10 times) than its tetracationic counterpart. This result has been attributed to the different anchoring arrangements of the two porphyrins to the TiO2 surface and their different states of aggregation within the film. Finally, there was an observed decrease of the emission fluorescence intensity in consecutive cycles of exposure and recovery due to the formation of ammonium chloride inside the film.We thank the Junta de AndalucĂa (Project: FQM-2310), the European Regional Development
Funds program (EU-FEDER) and the Spanish Ministry of Economy and Competitiveness (Projects:
MAT2013-40852-R, MAT2013-42900-P, MAT2014-57652-C2-2-R, MAT2015-69035-REDC, MINECO-CSIC
201560E055, PCIN-2015-169-C02-02 under a 2014 M-Era.Net project and RECUPERA 2020), for financial support.
We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)
ReologĂa de oleogeles basados en monoestearatos de sorbitano y glicerilo y aceites vegetales para aplicaciones lubricantes
Oleogels based on sorbitan and glyceryl monostearates and different types of vegetable oils, potentially applicable as biodegradable alternatives to traditional lubricating greases, have been studied. In particular, the rheological behavior, by means of small-amplitude oscillatory shear (SAOS) measurements, and some lubrication performance-related properties (mechanical stability and tribological response) have been evaluated in this work. SAOS response and mechanical stability of these oleogels are significantly influenced by the type and concentration of the organogelator and the vegetable oil used in the formulations. Glyceryl monostearate (GMS) generally produces stronger gels than sorbitan monostearate (SMS). The use of low-viscosity oils, such as rapeseed and soybean oils, yields gels with significantly higher values of the linear viscoelastic functions than oleogels prepared with high-viscosity oils, i.e. castor oil. The rheological behavior of SMS-based oleogels also depends on the cooling rate applied during the gelification process. On the other hand, the oleogels studied present low values of the friction coefficient obtained in a tribological contact, although only some GMS/castor oil-based oleogels exhibit a suitable mechanical stability.En el presente trabajo se han estudiado diferentes oleogeles, basados en monoestearatos de sorbitano y glicerilo y aceites vegetales, que podrĂan ser potencialmente empleados como alternativas biodegradables a las grasas lubricantes tradicionales. En concreto, se ha evaluado su comportamiento reolĂłgico, a travĂŠs de ensayos en cizalla oscilatoria, y algunas propiedades relacionadas con su rendimiento en la lubricaciĂłn, tales como su estabilidad mecĂĄnica y comportamiento tribolĂłgico. La respuesta reolĂłgica y la estabilidad mecĂĄnica de los oleogeles estudiados estĂĄn significativamente influenciadas por el tipo y la concentraciĂłn del agente gelificante y por el aceite vegetal empleado. AsĂ, el monoestearato de glicerilo (GMS) produce, generalmente, geles mĂĄs fuertes que el monoestearato de sorbitano (SMS). El uso de aceites de baja viscosidad, como los aceites de colza o de soja, dan lugar a geles con valores mĂĄs altos de las funciones viscoelĂĄsticas lineales que los oleogeles preparados con aceite de ricino. El comportamiento reolĂłgico de los oleogeles de SMS depende, ademĂĄs, de la velocidad de enfriamiento durante la gelificaciĂłn. Por otra parte, los oleogeles estudiados presentan bajos valores del coeficiente de fricciĂłn, determinado en un contacto tribolĂłgico, aunque sĂłlo algunos oleogeles que contienen GMS y aceite de ricino muestran una estabilidad mecĂĄnica adecuada
Enhanced stability of perovskite solar cells incorporating dopant-free Crystalline spiro-OMeTAD layers by vacuum sublimation
The main handicap still hindering the eventual exploitation of organometal halide perovskite-based solar cells is their poor stability under prolonged illumination, ambient conditions, and increased temperatures. This article shows for the first time the vacuum processing of the most widely used solid-state hole conductor (SSHC), i.e., the Spiro-OMeTAD [2,2â˛,7,7â˛-tetrakis (N,N-di-p-methoxyphenyl-amine) 9,9â˛-spirobifluorene], and how its dopant-free crystalline formation unprecedently improves perovskite solar cell (PSC) stability under continuous illumination by about two orders of magnitude with respect to the solution-processed reference and after annealing in air up to 200 °C. It is demonstrated that the control over the temperature of the samples during the vacuum deposition enhances the crystallinity of the SSHC, obtaining a preferential orientation along the ĎâĎ stacking direction. These results may represent a milestone toward the full vacuum processing of hybrid organic halide PSCs as well as light-emitting diodes, with promising impacts on the development of durable devices. The microstructure, purity, and crystallinity of the vacuum sublimated Spiro-OMeTAD layers are fully elucidated by applying an unparalleled set of complementary characterization techniques, including scanning electron microscopy, X-ray diffraction, grazing-incidence small-angle X-ray scattering and grazing-incidence wide-angle X-ray scattering, X-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy.The authors thank the âAgencia Estatal de InvestigaciĂłnâ, âConsejerĂa de EconomĂa y Conocimiento de la Junta de AndalucĂaâ (USâ1263142), âMinisterio de EconomĂa y Competitividadâ (MAT2016â79866âR, MAT2013â42900âP, FPA2016â77689âC2â1âR, and MAT2016â76892âC3â2âR) and the European Union (EU) through cohesion fund and FEDER 2014â2020 programs for financial support. J.R.S.âV. and A.B. acknowledge the EU project PlasmaPerovSol and funding from the European Union's Horizon 2020 research and innovation programme under the Marie SkĹodowskaâCurie grant agreement ID 661480. J.R.S.âVâ and M.C.L.âS. thank the University of Seville through the VI âPlan Propio de InvestigaciĂłn y Transferencia de la USâ (VI PPITâUS). This research has received funding from the EUâH2020 research and innovation programme under Grant Agreement No. 654360 having benefitted from the access provided by Technische Universität Graz at ElettraâTUG in Trieste (IT) within the framework on the NFFA (Nanoscience Foundries & Fine Analysis) Europe Transnational Access Activity. F.J.A. and J.R.S.âV. acknowledge the âJuan de la Ciervaâ and âRamon y Cajalâ national programs, respectively
Direct Measurement of Nuclear Dependence of Charged Current Quasielastic-like Neutrino Interactions using MINERvA
Charged-current interactions on carbon, iron, and lead with a
final state hadronic system of one or more protons with zero mesons are used to
investigate the influence of the nuclear environment on quasielastic-like
interactions. The transfered four-momentum squared to the target nucleus,
, is reconstructed based on the kinematics of the leading proton, and
differential cross sections versus and the cross-section ratios of iron,
lead and carbon to scintillator are measured for the first time in a single
experiment. The measurements show a dependence on atomic number. While the
quasielastic-like scattering on carbon is compatible with predictions, the
trends exhibited by scattering on iron and lead favor a prediction with
intranuclear rescattering of hadrons accounted for by a conventional particle
cascade treatment. These measurements help discriminate between different
models of both initial state nucleons and final state interactions used in the
neutrino oscillation experiments
The scattering of SH waves by a finite crack with a superposition based diffraction technique
The problem of diffraction of cylindrical and plane SH waves by a finite crack is revisited -- We construct an approximate solution by the addition of independent diffracted terms -- We start with the derivation of the fundamental case of a semi-infinite crack obtained as a degenerate case of generalized wedge -- This building block is then used to compute the diffraction of the main incident waves -- The interaction between the opposite edges of the crack is then considered one term at a time until a desired tolerance is reached -- We propose a recipe to determine the number of required interactions as a function of frequency -- The solution derived with the superposition technique can be applied at low and high frequencie
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
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