3,261 research outputs found

    Thermal Conductivity of Sand-Silt Mixtures

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    Heat flow controls the design and operation of a wide range of engineered geosystems. This study uses transient thermal probe measurements to determine the evolution of the thermal conductivity of air-dry and water-saturated sand–silt mixtures as a function of effective stress. Results confirm that the thermal conductivity of soils varies with state of stress, dry mass density, mineralogy, and pore fluid properties and highlight the effect of thermal contact resistance on the thermal conductivity of granular materials. Thermal conductivity follows a linear relationship with the logarithm of effective stress as a consequence of fabric compaction, increased coordination number, contact deformation, and reduced thermal contact resistance. The bulk thermal conductivity of water-saturated soils is more than seven times that of air-dry soils for the same fines content (FC) and effective stress. Pore-filling fines contribute conduction paths and interparticle coordination; the peak in thermal conductivity takes place at FC ≈ 0.4; this mixture range corresponds to the transition from fines-controlled to coarse-controlled mechanical response (i.e., both fines and coarse grains are load bearing), in agreement with the revised soil classification system

    Characterization and Engineering Properties of Dry and Ponded Class-F Fly Ash

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    Characterization studies conducted on Class-F fly-ash specimens gathered from different producers in the southeastern United States confirm general trends reported for fly ash worldwide. Additional tests and detailed analyses explain the spread in specific gravity (interparticle porosity cenospheres), highlight the tendency to segregation and layering, and show marked ferromagnetism. Furthermore, data show that early diagenetic cementation—within days after wetting—hinders densification and produces a fabric that is prone to collapse. New procedures are specifically developed to diagnose and characterize early diagenesis, including (1) pH measurements as an indicator of diagenetic potential, (2) test protocols to assess early diagenesis using oedometer tests and shear-wave velocity, and (3) procedures to determine realizable unit weights as reference values for the analyses of contractive or dilative tendencies and instability. In the absence of early diagenetic cementation, dilative fly-ash behavior is expected in the upper ≈20  m under monotonic shear loading. Flow instability may follow the failure of the containment structure if the ponded ash is saturated and has experienced hindered densification

    Blood Biomarkers to Predict Long-Term Mortality after Ischemic Stroke

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    Biomarcador; Endostatina; Accident cerebrovascular isquèmicBiomarcador; Endostatina; Accidente cerebrovascular isquémicoBiomarker; Endostatin; Ischemic strokeStroke is a major cause of disability and death globally, and prediction of mortality represents a crucial challenge. We aimed to identify blood biomarkers measured during acute ischemic stroke that could predict long-term mortality. Nine hundred and forty-one ischemic stroke patients were prospectively recruited in the Stroke-Chip study. Post-stroke mortality was evaluated during a median 4.8-year follow-up. A 14-biomarker panel was analyzed by immunoassays in blood samples obtained at hospital admission. Biomarkers were normalized and standardized using Z-scores. Multiple Cox regression models were used to identify clinical variables and biomarkers independently associated with long-term mortality and mortality due to stroke. In the multivariate analysis, the independent predictors of long-term mortality were age, female sex, hypertension, glycemia, and baseline National Institutes of Health Stroke Scale (NIHSS) score. Independent blood biomarkers predictive of long-term mortality were endostatin > quartile 2, tumor necrosis factor receptor-1 (TNF-R1) > quartile 2, and interleukin (IL)-6 > quartile 2. The risk of mortality when these three biomarkers were combined increased up to 69%. The addition of the biomarkers to clinical predictors improved the discrimination (integrative discriminative improvement (IDI) 0.022 (0.007–0.048), p quartile 3 was an independent predictor of mortality due to stroke. Altogether, endostatin, TNF-R1, and IL-6 circulating levels may aid in long-term mortality prediction after stroke.This work has been funded by Instituto de Salud Carlos III (PI18/00804) and by La Fundació La Marató (Reg. 84/240 proj. 201702). Neurovascular Research Laboratory takes part in the Spanish stroke research network INVICTUS+ (RD16/0019/0021). L.R. is supported by a pre-doctoral fellowship from the Instituto de Salud Carlos III (IFI17/00012)

    High mammographic density in long-term night shift workers: DDM-Spain /Var-DDM

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    [EN] Background: Night-shift work (NSW) has been suggested as a possible cause of breast cancer, and its association with mammographic density (MD), one of the strongest risk factors for breast cancer, has been scarcely addressed. This study examined NSW and MD in Spanish women. Methods: The study covered 2,752 women aged 45-68 years recruited in 2007-2008 in 7 population-based public breast cancer screening centers, which included 243 women who had performed NSW for at least one year. Occupational data and information on potential confounders were collected by personal interview. Two trained radiologist estimated the percentage of MD assisted by a validated semiautomatic computer tool (DM-scan). Multivariable mixed linear regression models with random screening center-specific intercepts were fitted using log-transformed percentage of MD as the dependent variable and adjusting by known confounding variables. Results: Having ever worked in NSW was not associated with MD [e(beta):0.96; 95% confidence interval (CI), 0.86-1.06]. However, the adjusted geometric mean of the percentage of MD in women with NSW for more than 15 years was 25% higher than that of those without NSW history (MD>15 (years):20.7% vs. MDnever:16.5%; e(beta):1.25; 95% CI, 1.01-1.54). This association was mainly observed in postmenopausal participants (e(beta):1.28; 95% CI, 1.00-1.64). Among NSW-exposed women, those with <= 2 night-shifts per week had higher MD than those with 5 to 7 nightshifts per week (e(beta):1.42; 95% CI, 1.10-1.84). Conclusions: Performing NSW was associated with higherMD only in women with more than 15 years of cumulated exposure. These findings warrant replication in futures studies. (C)2017 AACR.We would like to thank the participants in the DDM-Spain/Var-DDM-Spain study for their contribution to breast cancer research. Other members of DDM-Spain/Var-DDM: Gonzalo. López-Abente, Roberto Pastor-Barriuso, Pablo Fernández-Navarro, Anna Cabanes, Soledad Laso, Manuela Alcaraz, María Casals, Inmaculada Martínez, Juan Carlos Pérez Cortés, Joaquín Antón, Nieves Ascunce, Isabel González-Román, Ana Belén Fernández, Montserrat Corujo, Soledad Abad, and Jesús Vioque. A.M. Pedraza-Flechas FI14CIII/00013 PFIS; B. Perez-Gomez FIS PS09/0790; M. Pollán FIS PI060386, EPY1306/06 collaboration agreement between Astra-Zeneca and ISCIII, and FECMA 485 EPY 1170 10; R. LLobet Gent per Gent Fund (EDEMAC Project); All authors: European Regional Development Fund (FEDER). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.Pedraza-Flechas, AM.; Lope, V.; Sanchez-Contador, C.; Santamarina, C.; Pedraz-Pingarron, C.; Moreo, P.; Ederra, M.... (2017). High mammographic density in long-term night shift workers: DDM-Spain /Var-DDM. Cancer Epidemiology Biomarkers & Prevention. 26(6):905-913. https://doi.org/10.1158/1055-9965.EPI-16-0507S90591326

    Interactions between copper homeostasis and the fungal cell wall affect copper stress resistance

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    Copper homeostasis mechanisms are essential for microbial adaption to changing copper levels within the host during infection. In the opportunistic fungal pathogen Cryptococcus neoformans (Cn), the Cn Cbi1/Bim1 protein is a newly identified copper binding and release protein that is highly induced during copper limitation. Recent studies demonstrated that Cbi1 functions in copper uptake through the Ctr1 copper transporter during copper limitation. However, the mechanism of Cbi1 action is unknown. The fungal cell wall is a dynamic structure primarily composed of carbohydrate polymers, such as chitin and chitosan, polymers known to strongly bind copper ions. We demonstrated that Cbi1 depletion affects cell wall integrity and architecture, connecting copper homeostasis with adaptive changes within the fungal cell wall. The cbi1Δ mutant strain possesses an aberrant cell wall gene transcriptional signature as well as defects in chitin / chitosan deposition and exposure. Furthermore, using Cn strains defective in chitosan biosynthesis, we demonstrated that cell wall chitosan modulates the ability of the fungal cell to withstand copper stress. Given the previously described role for Cbi1 in copper uptake, we propose that this copper-binding protein could be involved in shuttling copper from the cell wall to the copper transporter Ctr1 for regulated microbial copper uptake

    Characterization and Engineering Properties of Dry and Ponded Class-F Fly Ash

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    Characterization studies conducted on Class-F fly-ash specimens gathered from different producers in the southeastern United States confirm general trends reported for fly ash worldwide. Additional tests and detailed analyses explain the spread in specific gravity (interparticle porosity cenospheres), highlight the tendency to segregation and layering, and show marked ferromagnetism. Furthermore, data show that early diagenetic cementation—within days after wetting—hinders densification and produces a fabric that is prone to collapse. New procedures are specifically developed to diagnose and characterize early diagenesis, including (1) pH measurements as an indicator of diagenetic potential, (2) test protocols to assess early diagenesis using oedometer tests and shear-wave velocity, and (3) procedures to determine realizable unit weights as reference values for the analyses of contractive or dilative tendencies and instability. In the absence of early diagenetic cementation, dilative fly-ash behavior is expected in the upper ≈20  m under monotonic shear loading. Flow instability may follow the failure of the containment structure if the ponded ash is saturated and has experienced hindered densification

    Occurrence of moulds associated with ovine raw milk and cheeses of the Spanish region of Castilla La Mancha

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    The distribution of mould species was examined at several points of the processing chain in a Manchego cheese plant and associated dairy farms. Geotrichum and Fusarium were the most frequent genera isolated in milk samples as well as in 1-month ripened cheeses, evidencing a direct transfer from raw milk. Conversely, the mycobiota of long-ripened cheeses consisted mainly of Penicillium species, which gained entry to the cheese through the air of ripening rooms. This study contributes to the understanding of the dynamics of fungal populations in semihard and hard cheeses, highlighting that airborne transfer from the stables could have a direct impact on their quality

    End-to-end tests of the TuMag instrument for the SUNRISE III mission

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    Ground-based and airborne instrumentation for astronomy IX (2022), Montreal, jul 17-22, 2022.--Proceedings of SPIE - The International Society for Optical Engineering vol. 12184 Article number 121842FSUNRISE III mission is a one-meter aperture telescope onboard a balloon within NASA Long Duration Balloon Program. Three post-focus instruments are used for studying the Sun's dynamics and magnetism, among which the Tunable Magnetograph (TuMag) is a tunable imaging spectropolarimeter. TuMag is a diffraction-limited imager, a high sensitivity polarimeter (< 10(-3)), and a high-resolution spectrometer (Delta lambda similar to 65 m angstrom). It will be able to study solar magnetic fields at high spatial resolution (similar to 100 km on the solar surface). It will make images of the solar surface magnetic field after measuring the state of polarization of light within three selected spectral lines: the Fe I lines at 525.02 nm and 525.06 nm, and the Mg I b2 line at 517.27 nm. It will be sensitive to the solar vector magnetic fields and line-of-sight velocities, in the photospheric and chromospheric layers. TuMag will be the first solar magnetograph onboard an aerospace platform with the capability of tuning the solar line to be observed. In this paper the TuMag end-to-end tests carried out during the verification phase are described. These tests are performed to characterize and calibrate the instrument. Specifically, they determine the polarimetric and spectroscopic performances of the instrument as well as the image quality. The availability of a singular facility, an ISO6 clean room with a coelostat on the building roof, allowed the use of solar light during the verification campaign. This was key to a complete instrument verification due to the unique spectroscopic and polarimetric characteristics of solar light.The authors would like to thank Ministerio de Ciencia e Innovacion from the Spanish government for the support of this research via the grant Space Solar Physics RTI2018-096886-B-C5 and "Centro de Excelencia Severo Ochoa" grant SEV-2017-0709.Peer reviewe

    VLDL Hydrolysis by Hepatic Lipase Regulates PPARδ Transcriptional Responses

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    PPARs (α,γ,δ) are a family of ligand-activated transcription factors that regulate energy balance, including lipid metabolism. Despite these critical functions, the integration between specific pathways of lipid metabolism and distinct PPAR responses remains obscure. Previous work has revealed that lipolytic pathways can activate PPARs. Whether hepatic lipase (HL), an enzyme that regulates VLDL and HDL catabolism, participates in PPAR responses is unknown.Using PPAR ligand binding domain transactivation assays, we found that HL interacted with triglyceride-rich VLDL (>HDL≫LDL, IDL) to activate PPARδ preferentially over PPARα or PPARγ, an effect dependent on HL catalytic activity. In cell free ligand displacement assays, VLDL hydrolysis by HL activated PPARδ in a VLDL-concentration dependent manner. Extended further, VLDL stimulation of HL-expressing HUVECs and FAO hepatoma cells increased mRNA expression of canonical PPARδ target genes, including adipocyte differentiation related protein (ADRP), angiopoietin like protein 4 and pyruvate dehydrogenase kinase-4. HL/VLDL regulated ADRP through a PPRE in the promoter region of this gene. In vivo, adenoviral-mediated hepatic HL expression in C57BL/6 mice increased hepatic ADRP mRNA levels by 30%. In ob/ob mice, a model with higher triglycerides than C57BL/6 mice, HL overexpression increased ADRP expression by 70%, demonstrating the importance of triglyceride substrate for HL-mediated PPARδ activation. Global metabolite profiling identified HL/VLDL released fatty acids including oleic acid and palmitoleic acid that were capable of recapitulating PPARδ activation and ADRP gene regulation in vitro.These data define a novel pathway involving HL hydrolysis of VLDL that activates PPARδ through generation of specific monounsaturated fatty acids. These data also demonstrate how integrating cell biology with metabolomic approaches provides insight into specific lipid mediators and pathways of lipid metabolism that regulate transcription
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