290 research outputs found

    Reactivity and fate of secondary alkane sulfonates (SAS) in marine sediments

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    This research is focused on secondary alkane sulfonates (SAS), anionic surfactants widely used in household applications that access aquatic environments mainly via sewage discharges.We studied their sorption capacity and anaerobic degradation in marine sediments, providing the first data available on this topic. SAS partition coefficients increased towards those homologues having longer alkyl chains(from up to 141 L kg 1 for C14 to up to 1753 L kg 1 for C17), which were those less susceptible to undergo biodegradation. Overall, SAS removal percentages reached up to 98% after 166 days of incubation using anoxic sediments. The degradation pathway consisted on the formation of sulfocarboxylic acids after an initial fumarate attack of the alkyl chain and successive b-oxidations. This is the first study showing that SAS can be degraded in absence of oxygen, so this new information should be taken into account for future environmental risk assessments on these chemicals

    PELIGROSIDAD A LOS MOVIMIENTOS DE LADERA EN LA VERTIENTE MERIDIONAL DE SIERRA NEVADA (GRANADA) A PARTIR DE LA ESTIMACIÓN MULTI-TÉCNICA DE LA ACTIVIDAD

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    El presente trabajo aborda la cartografía de la susceptibilidad y la peligrosidad a los movimientos de ladera, en un ambiente montañoso, con información limitada sobre su actividad. El análisis y validación de la susceptibilidad se realizada mediante un modelo elaborado a partir del ModelBuilder™ de ArcGIS basado en el Método de la Matriz en un SIG. Dicho modelo necesita una cartografía previa de los movimientos, un MDE y un análisis discriminante de los factores determinantes de la estabilidad. Los datos del análisis reflejan que el 15% de la zona estudiada muestra una susceptibilidad a los movimientos de moderada a muy alta que, a su vez, coincide con lugares donde se encuentran la mayoría de las infraestructuras públicas de la región. Además, los valores registrados en la validación mediante el grado de ajuste están por encima del 83% para las zonas de susceptibilidad alta y muy alta. Estas zonas que presentan un mayor grado de susceptibilidad y, por tanto, una mayor exposición potencial al riesgo, son las seleccionadas para el análisis detallado de la peligrosidad. El principal problema, que, por otra parte, suele ser generalizado en este tipo de áreas para la estimación de la frecuencia con la que se suceden movimientos de ladera, es la falta de información sobre su ocurrencia. Por tanto, y con el objetivo de obtener la mayor información posible, los datos relativos a la actividad de los movimientos se extraen de diversas fuentes y técnicas, de forma que interactivamente solventen sus correspondientes limitaciones. Estos datos se extraen de una documentación previa, tanto en prensa como bibliografía específica, donde se presentan trabajos sobre DInSAR, fotogrametría aérea y LIDAR, y TLS. Además, se realiza de forma específica un análisis dendrogeomorfológico de árboles en movimientos de ladera y se revisa la ortofotografía aérea histórica de la zona de estudio. Posteriormente, con los datos de actividad, se realiza un análisis de los factores desencadenantes, que refleja que los movimientos de ladera están relacionados con episodios de precipitaciones intensas y prolongadas, y no tanto con la actividad sísmica del área. Por último, de forma indirecta, se estima la peligrosidad de la zona de estudio a los movimientos de ladera, asociando los resultados obtenidos de actividad con los factores desencadenantes; esto es, con periodos de precipitaciones intensas. Así, se establece un periodo de retorno que se extrapola a toda el área, con la asunción de que los grandes deslizamientos se generan o reactivan, conjuntamente con movimientos superficiales, tras periodos lluviosos intensos y prolongados, y que las lluvias torrenciales generan movimientos de ladera superficiales tipo flujo y desprendimientos. Los resultados obtenidos indican que la frecuencia con la que se generan los movimientos es de 5 años para los flujos superficiales y desprendimientos (F=0,2), y de 18 años para los deslizamientos y movimientos complejos (F=0,06). La zona, en términos generales, presenta determinados sectores con susceptibilidad moderada a muy alta, sin embargo la peligrosidad a los movimientos de ladera es de moderada a muy baja. En términos de probabilidad temporal, los flujos y desprendimientos son los movimientos con mayor peligrosidad

    Pseudo-arthrosis repair of a posterior cruciate ligament avulsion fracture

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    A pseudo-arthrosis repair of a 4-year-old bony avulsion fracture of the PCL using a minimally invasive technique, screw fixation, and bone grafting is reported. The case presented seems to be rather unique due to the fragment size and the approach for pseudo-arthrosis repair. There was a good functional result following minimally invasive pseudo-arthrosis repair of a posterior cruciate ligament avulsion fracture. There are no previous reports of similar pseudo-arthrosis repairs, and other authors report good results of delayed refixation of PCL avulsion fractures. Therefore, refixation and pseudo-arthrosis repair should be considered as a viable treatment

    Experimental survey of soil CO2 content over a karstic cave in mediterranean climate

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    The CO2 content and the temperature of the air have been measured within the scarce soil (although with relatively high organic matter concentration) which partially covers the carbonate outcrops over the Nerja Cave (Málaga). General yearly average values of around 850 ppm and 25 ºC have been identified, both using continuous recording devices and separated measures with portable equipment. Temperature evolution closely follows that of the outside atmosphere. Spatial variations in CO2 contents are related with the vegetal cover and with the soil depth. Seasonal variations are important, with a maximum of more than 1000 ppm in May (main vegetation development) and minimum (around 350- 500) in December. Daily oscillations have also been identified, ranging up to more than 600 ppm in the period of maximum CO2 production. These results agree with estimates based in hydrogeochemical modelling as well as in the TOC content of drip water to the cav

    Using RGB-D sensors and evolutionary algorithms for the optimization of workstation layouts

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    [EN] RGB-D sensors can collect postural data in an automatized way. However, the application of these devices in real work environments requires overcoming problems such as lack of accuracy or body parts' occlusion. This work presents the use of RGB-D sensors and genetic algorithms for the optimization of workstation layouts. RGB-D sensors are used to capture workers' movements when they reach objects on workbenches. Collected data are then used to optimize workstation layout by means of genetic algorithms considering multiple ergonomic criteria. Results show that typical drawbacks of using RGB-D sensors for body tracking are not a problem for this application, and that the combination with intelligent algorithms can automatize the layout design process. The procedure described can be used to automatically suggest new layouts when workers or processes of production change, to adapt layouts to specific workers based on their ways to do the tasks, or to obtain layouts simultaneously optimized for several production processes.This work was supported by the Programa estatal de investigacion, desarrollo e innovacion orientada a los retos de la sociedad of the Government of Spain under Grant TIN2013-42504-R.Diego-Mas, JA.; Poveda Bautista, R.; Garzon-Leal, D. (2017). Using RGB-D sensors and evolutionary algorithms for the optimization of workstation layouts. Applied Ergonomics. 65:530-540. doi:10.1016/j.apergo.2017.01.012S5305406

    Integration of light and circadian signals that regulate chloroplast transcription by a nuclear-encoded sigma factor

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    We investigated the signalling pathways that regulate chloroplast transcription in response to environmental signals. One mechanism controlling plastid transcription involves nuclear‐encoded sigma subunits of plastid‐encoded plastid RNA polymerase. Transcripts encoding the sigma factor SIG5 are regulated by light and the circadian clock. However, the extent to which a chloroplast target of SIG5 is regulated by light‐induced changes in SIG5 expression is unknown. Moreover, the photoreceptor signalling pathways underlying the circadian regulation of chloroplast transcription by SIG5 are unidentified. We monitored the regulation of chloroplast transcription in photoreceptor and sigma factor mutants under controlled light regimes in Arabidopsis thaliana. We established that a chloroplast transcriptional response to light intensity was mediated by SIG5; a chloroplast transcriptional response to the relative proportions of red and far red light was regulated by SIG5 through phytochrome and photosynthetic signals; and the circadian regulation of chloroplast transcription by SIG5 was predominantly dependent on blue light and cryptochrome. Our experiments reveal the extensive integration of signals concerning the light environment by a single sigma factor to regulate chloroplast transcription. This may originate from an evolutionarily ancient mechanism that protects photosynthetic bacteria from high light stress, which subsequently became integrated with higher plant phototransduction networks

    Dynamics of biofilm formation and the interaction between Candida albicans and methicillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA)

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    Polymicrobial biofilms are an understudied and a clinically relevant problem. This study evaluates the interaction between C. albicans, and methicillin- susceptible (MSSA) and resistant (MRSA) S. aureus growing in single- and dual-species biofilms. Single and dual species adhesion (90 min) and biofilms (12, 24, and 48 h) were evaluated by complementary methods: counting colony-forming units (CFU mL-1), XTT-reduction, and crystal violet staining (CV). The secretion of hydrolytic enzymes by the 48 h biofilms was also evaluated using fluorimetric kits. Scanning electron microscopy (SEM) was used to assess biofilm structure. The results from quantification assays were compared using two-way ANOVAs with Tukey post-hoc tests, while data from enzymatic activities were analyzed by one-way Welch-ANOVA followed by Games-Howell post hoc test ( = 0.05). C. albicans, MSSA and MRSA were able to adhere and to form biofilm in both single or mixed cultures. In general, all microorganisms in both growth conditions showed a gradual increase in the number of cells and metabolic activity over time, reaching peak values between 12 h and 48 h (<0.05). C. albicans single- and dual-biofilms had significantly higher total biomass values (<0.05) than single biofilms of bacteria. Except for single MRSA biofilms, all microorganisms in both growth conditions secreted proteinase and phospholipase-C. SEM images revealed extensive adherence of bacteria to hyphal elements of C. albicans. C. albicans, MSSA, and MRSA can co-exist in biofilms without antagonism and in an apparent synergistic effect, with bacteria cells preferentially associated to C. albicans hyphal forms.CNPq (Council for Technical and Scientific Development) (Grant 400658/2012-7)Fundação para a Ciência e Tecnologia (FCT), Portugal (SFRH/BPD/71076/2010)CAPES(Coordination for the Improvement of Higher Level Personnel

    Carbon Dynamics, Development and Stress Responses in Arabidopsis: Involvement of the APL4 Subunit of ADP-Glucose Pyrophosphorylase (Starch Synthesis)

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    An Arabidopsis thaliana T-DNA insertional mutant was identified and characterized for enhanced tolerance to the singlet-oxygen-generating herbicide atrazine in comparison to wild-type. This enhanced atrazine tolerance mutant was shown to be affected in the promoter structure and in the regulation of expression of the APL4 isoform of ADP-glucose pyrophosphorylase, a key enzyme of the starch biosynthesis pathway, thus resulting in decrease of APL4 mRNA levels. The impact of this regulatory mutation was confirmed by the analysis of an independent T-DNA insertional mutant also affected in the promoter of the APL4 gene. The resulting tissue-specific modifications of carbon partitioning in plantlets and the effects on plantlet growth and stress tolerance point out to specific and non-redundant roles of APL4 in root carbon dynamics, shoot-root relationships and sink regulations of photosynthesis. Given the effects of exogenous sugar treatments and of endogenous sugar levels on atrazine tolerance in wild-type Arabidopsis plantlets, atrazine tolerance of this apl4 mutant is discussed in terms of perception of carbon status and of investment of sugar allocation in xenobiotic and oxidative stress responses

    Altered Retinoic Acid Metabolism in Diabetic Mouse Kidney Identified by 18O Isotopic Labeling and 2D Mass Spectrometry

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    Numerous metabolic pathways have been implicated in diabetes-induced renal injury, yet few studies have utilized unbiased systems biology approaches for mapping the interconnectivity of diabetes-dysregulated proteins that are involved. We utilized a global, quantitative, differential proteomic approach to identify a novel retinoic acid hub in renal cortical protein networks dysregulated by type 2 diabetes.Total proteins were extracted from renal cortex of control and db/db mice at 20 weeks of age (after 12 weeks of hyperglycemia in the diabetic mice). Following trypsinization, (18)O- and (16)O-labeled control and diabetic peptides, respectively, were pooled and separated by two dimensional liquid chromatography (strong cation exchange creating 60 fractions further separated by nano-HPLC), followed by peptide identification and quantification using mass spectrometry. Proteomic analysis identified 53 proteins with fold change >or=1.5 and p<or=0.05 after Benjamini-Hochberg adjustment (out of 1,806 proteins identified), including alcohol dehydrogenase (ADH) and retinaldehyde dehydrogenase (RALDH1/ALDH1A1). Ingenuity Pathway Analysis identified altered retinoic acid as a key signaling hub that was altered in the diabetic renal cortical proteome. Western blotting and real-time PCR confirmed diabetes-induced upregulation of RALDH1, which was localized by immunofluorescence predominantly to the proximal tubule in the diabetic renal cortex, while PCR confirmed the downregulation of ADH identified with mass spectrometry. Despite increased renal cortical tissue levels of retinol and RALDH1 in db/db versus control mice, all-trans-retinoic acid was significantly decreased in association with a significant decrease in PPARbeta/delta mRNA.Our results indicate that retinoic acid metabolism is significantly dysregulated in diabetic kidneys, and suggest that a shift in all-trans-retinoic acid metabolism is a novel feature in type 2 diabetic renal disease. Our observations provide novel insights into potential links between altered lipid metabolism and other gene networks controlled by retinoic acid in the diabetic kidney, and demonstrate the utility of using systems biology to gain new insights into diabetic nephropathy
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