6,068 research outputs found

    A Configurable Smart E-Nose for Spatio-Temporal Olfactory Analysis

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    This paper describes a novel electronic nose (enose) aimed at applications that require knowing not only the gas composition and concentration, but also its temporal and spatial evolution. This is done by capturing additional information related to the chemical substance such as the timestamp and geo-location of the measurements, as well as other physical magnitudes of the environment like temperature and humidity for correcting and interpreting the data. The device has been conceived following a modular architecture as a set of independent smart modules, which are interconnected and controlled through an I2C interface by a central processing unit. Each smart module can identify itself, store settings for autoconfiguration and perform signal pre-processing of the measured variables. Smart module types include: chemical sensors, communication interfaces, batteries, data storage, GPS, temperature and humidity.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Creating maps of VOC odors in urban areas by cycling with a portable e-nose

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    This work describes an application for monitoring volatile organic compounds (VOCs) in urban areas, likely coming from residential waste or the public sewage system. The objective is to obtain a spatial and temporal representation of such odors by means of a gas distribution map, from which valuable information such as the location, or the time-intervals of maximum strength of the nuisance odors can be inferred. The necessary data: chemical, temporal and spatial; is provided by a GPS and a specific e-nose accommodating eight metal oxide (MOX) gas sensors, both mounted on a bicycle. The results of a monitoring campaign carried out in a town in southern Spain are presented. The campaign comprises nine measurement runs distributed along three consecutive days, with a total path of more than 90Km. Fig.1 shows an illustrative example of the data collected during this process, and the generated geo-referenced gas distribution maps. As can be appreciated, the chemical, temporal and spatial data are successfully merged to obtain representative information about the presence of VOCs in the urban area. A deeper analysis comprising the study of the areas showing the higher VOCs concentration, as well as the temporal variability among the different days and hours within the day are also provided.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Proyectos de Excelencia de la Junta de Andalucía: TEP08-4016 y TEP2012-53

    Hybrid Catalysts Comprised of Graphene Modified with Rhodium-Based N-Heterocyclic Carbenes for Alkyne Hydrosilylation

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    Thermally partially reduced graphene oxide has been covalently modified with 3-methyl-4-phenyl-1, 2, 3-triazolium salts making use of the epoxy functionalities on the carbon nanomaterial. Characterization of the functionalized materials through adequate solid characterization techniques, particularly X-ray photoelectron spectroscopy (XPS), allows one to follow the stepwise building up of the triazolium fragments on the graphene oxide attached to the wall via covalent C-N linkage. The hydroxyl-triazolium-functionalized materials have been used to prepare rhodium hybrid materials containing either alkoxo or triazolylidene molecular rhodium(I) complexes depending on the protection of the hydroxyl groups present in the material. Characterization of the heterogeneous systems, especially by means of XPS and extended X-ray absorption fine structure (EXAFS) spectroscopy, has evidenced the coordination sphere of the supported rhodium(I) complexes in both rhodium hybrid materials. The graphene-oxide-supported rhodium triazolylidene hybrid catalysts show excellent activity, comparable to that of the homogeneous [RhI(cod)(Triaz)] (Triaz = 1, 4-diphenyl-3-methyl-1, 2, 3-triazol-5-ylidene) catalyst, for the hydrosilylation of terminal and internal alkynes. In addition, these catalysts have shown good selectivity to the beta-(Z) vinylsilane isomers (for the not hindered terminal substrates) or syn-additions (for the internal substrates). In contrast to the rhodium(I)-alkoxo-based hybrid material, the silyl-protected rhodium(I)-triazolylidene-based hybrid catalyst can be reused in consecutive cycles without loss of activity maintaining the selectivity. The lack of leaching of active rhodium species demonstrates the strength of the C-N covalent bond of the triazolylidene linker to the graphitic wall

    Extraction of the antioxidant phytocomplex from wine-making by-products and sustainable loading in phospholipid vesicles specifically tailored for skin protection

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    The present study is aimed at valorizing grape pomace, one of the most abundant winery-making by-products of the Mediterranean area, through the extraction of the main bioactive compounds from the skin of grape pomace and using them to manufacture innovative nanoformulations capable of both avoiding skin damages and promoting skincare. The phytochemicals were recovered through maceration in hydroethanolic solution. Catechin, quercetin, fisetin and gallic acid, which are known for their antioxidant power, were detected as the main compounds of the extract. Liposomes and phospholipid vesicles modified with glycerol or Montanov 82® or a combination of both, were used as carriers for the extract. The vesicles were small (~183 nm), slightly polydispersed (PI ≥ 0.28), and highly negatively charged (~−50 mV). The extract was loaded in high amounts in all vesicles (~100%) irrespective of their composition. The antioxidant activity of the extract, measured by using the DPPH (2,2-Diphenyl-1-picrylhydrazyl) test, was 84 ± 1%, and slightly increased when loaded into the vesicles (~89%, P < 0.05). The grape pomace extract loaded vesicles were highly biocompatible and able to protect fibroblasts (3T3) from the oxidative stress induced by hydrogen peroxide

    The GAPS Programme with HARPS-N@TNG IX. The multi-planet system KELT-6: detection of the planet KELT-6 c and measurement of the Rossiter-McLaughlin effect for KELT-6 b

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    Aims. For more than 1.5 years we monitored spectroscopically the star KELT-6 (BD+312447), known to host the transiting hot Saturn KELT-6b, because a previously observed long-term trend in radial velocity time series suggested the existence of an outer companion. Methods. We collected a total of 93 new spectra with the HARPS-N and TRES spectrographs. A spectroscopic transit of KELT-6b was observed with HARPS-N, and simultaneous photometry was obtained with the IAC-80 telescope. Results. We proved the existence of an outer planet with a mininum mass Mp_{\rm p}sini=3.71±\pm0.21 MJup_{\rm Jup} and a moderately eccentric orbit (e=0.210.036+0.039e=0.21_{-0.036}^{+0.039}) of period P\sim3.5 years. We improved the orbital solution of KELT-6b and obtained the first measurement of the Rossiter-McLaughlin effect, showing that the planet has a likely circular, prograde, and slightly misaligned orbit, with a projected spin-orbit angle λ\lambda=-36±\pm11 degrees. We improved the KELT-6b transit ephemeris from photometry, and we provided new measurements of the stellar parameters. KELT-6 appears as an interesting case to study the formation and evolution of multi-planet systems.Comment: Letter, 4 figures, accepted for publication in A&A. Some language editing and numbering of the paper series changed (from X to IX

    Truncated tau interferes with the autophagy and endolysosomal pathway and results in lipid accumulation

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    This is the final version. Available from Springer via the DOI in this record. Availability of data and material. The data that support the findings of this study are available from the corresponding author upon reasonable request.The autophagy-lysosomal pathway plays a critical role in the clearance of tau protein aggregates that deposit in the brain in tauopathies, and defects in this system are associated with disease pathogenesis. Here, we report that expression of Tau35, a tauopathy-associated carboxy-terminal fragment of tau, leads to lipid accumulation in cell lines and primary cortical neurons. Our findings suggest that this is likely due to a deleterious block of autophagic clearance and lysosomal degradative capacity by Tau35. Notably, upon induction of autophagy by Torin 1, Tau35 inhibited nuclear translocation of transcription factor EB (TFEB), a key regulator of lysosomal biogenesis. Both cell lines and primary cortical neurons expressing Tau35 also exhibited changes in endosomal protein expression. These findings implicate autophagic and endolysosomal dysfunction as key pathological mechanisms through which disease-associated tau fragments could lead to the development and progression of tauopathy

    The Lyth Bound and the End of Inflation

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    We derive an extended version of the well-known Lyth Bound on the total variation of the inflaton field, incorporating higher order corrections in slow roll. We connect the field variation Δϕ\Delta\phi to both the spectral index of scalar perturbations and the amplitude of tensor modes. We then investigate the implications of this bound for ``small field'' potentials, where the field rolls off a local maximum of the potential. The total field variation during inflation is {\em generically} of order mPlm_{\rm Pl}, even for potentials with a suppressed tensor/scalar ratio. Much of the total field excursion arises in the last e-fold of inflation and in single field models this problem can only be avoided via fine-tuning or the imposition of a symmetry. Finally, we discuss the implications of this result for inflationary model building in string theory and supergravity.Comment: 10 pages, RevTeX, 2 figures (V3: version accepted for publication by JCAP

    Risks of dengue secondary infective biting associated with aedes aegypti in home environments in Monterrey, Mexico

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    Abstract. Secondary dengue virus infections are a major risk for developing dengue hemorrhagic fever. Recent exposure to infectious bites of Aedes aegypti (L.) females in previously diagnosed dengue cases fulfills the epidemiological model of dengue hemorrhagic fever. A study was comprised of 357 (89.2%) dengue and 43 (10.8%) dengue hemorrhagic fever cases confirmed by laboratory tests and clinical manifestations. An entomological survey was done in homes and backyards. Concurrently, a questionnaire was used to assess the impact of healthpromotion campaigns through knowledge of the vector and its epidemiological role. Seventy-six (28.4%) of the 268 (67.0%) total wet or dry oviposition sites were positive for the presence of larvae or pupae, while adult Ae. aegypti were found in 32 (8.0%). One hundred thirty-two (33%) householders who formerly had dengue fever or dengue hemorrhagic fever had knowledge of either larval or adult dengue vector stages. According to gender distribution, 145 (36.2%) and 14 (3.5%) of the males confirmed with cases of dengue and dengue hemorrhagic fever lived in houses with 17.9 and 2% of the Ae. aegypti larval and pupal habitats. Houses with females who had dengue and dengue hemorrhagic fever were 212 (53%) and 29 (7.3%), with containers with immature Ae. aegypti in 19.4 and 7%, respectively. Lack of sustainability of government-targeted health education campaigns is the major problem for involving communities in prevention and control of dengu
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