484 research outputs found

    New high resolution calcareous nannofossil analysis across the Danian / Selandian transition at the Zumaia section: comparison with South Tethys and Danish sections

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    A high resolution calcareous nannofossil biostratigraphic analysis was carried out across the Danian/Selandian transition at the Zumaia section (western Pyrenees). In the studied interval, spanning Varol’s Subzone NTp7a to Zone NTp9, a sequence of 10 distinct calcareous nannofossil events is identified. The recognition of these bioevents confirms the continuous and expanded character of the Zumaia section and allows an accurate biostratigraphic correlation of the D/S transition between Zumaia, the Danish reference sections and the more southerly Tethys sections. According to this correlation, the abrupt transition from the upper Danian limestones (the calcisiltite unit) to the Lellinge Greensand that marks the D/S boundary in the type area correlates with the lithological change from the Aitzgorri Limestone Formation to the Itzurun Formation in Zumaia. The calcareous nannofossil bioevents recorded in connection with the organic-rich layer used to mark the base of the Selandian in the Tethys region were detected in Zumaia ~10 m below the top of the Aitzgorri Limestone Formation. This finding suggests that the organic-rich layer is considerably older than the Danian/Selandian (D/S) boundary at Zumaia and the type area, and thus using it to mark the D/S boundary in Tethys is not appropriate. According to a counting of limestone/marl couplets, which are demonstrated to be the stratigraphic expression of precession cycles throughout the Zumaia section, the organic-rich layer in the Tethys region is ~546 kyr older than the D/S boundary at the type area

    Infinitesimal relative position vector fields for observers in a reference frame and applications to conformally stationary spacetimes

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    We introduce and analyze the concept of in nitesimal relative position vector eld between \in nitesimally nearby" observers, showing the equivalence between di erent de nitions. Through the Fermi-Walker derivative of in nitesimal relative position vector elds along an observer in a reference frame, we characterize spacetimes admitting an umbilic foliation. Su cient and necessary conditions for those spacetimes to be a conformally stationary spacetime are given. Finally, the important class of cosmological models known as generalized Robertson-Walker spacetimes is characterize

    Calcificaciones discales idiopáticas en la infancia: A propósito de un caso

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    Las calcificaciones discales en la infancia constituyen una rara entidad; frecuentemente son asintomáticas, pero en ocasiones producen síntomas como cervicalgia o dorsalgia. El pronóstico suele ser bueno en casi todos los pacientes. Presentamos el caso de un niño de 11 años de edad, que consultó por dolor en región dorsal, fiebre y una velocidad de sedimentación globular elevada. La radiología nos mostró la presencia de 2 calcificaciones discales en el segmento torácico. Tras una semana de tratamiento conservador, se produce una completa resolución del cuadro clínico, persistiendo las calcificaciones discales.Invertebral disc calcification in childhood is rare. Most frequently are not symptomatic, but occasionally evoke symptoms like neck pain or back pain. The prognosis of nearly all patients is good. We report on a 11-year-old child, who suffered from acute back pain, fever and elevated erythrocyte sedimentation rates. The X-Ray revealed two calcified discs in the thoracic region. After one week of conservative treatment, a complete resolution of the symptoms is observed, however the radiologic findings showed the persistence of invertebral disc calcifications

    Community-acquired pneumonia: development of a bedside predictive model and scoring system to identify the aetiology

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    AbstractAlthough initial presentation has been commonly used to select empirical therapy in patients with community-acquired pneumonia (CAP), few studies have provided a quantitative estimation of its value. The objective of this study was to analyse whether a combination of basic clinical and laboratory information performed at bedside can accurately predict the aetiology of pneumonia.A prospective study was developed among patients admitted to the Emergency Department University Hospital Arnau de Vilanova, Lleida, Spain, with CAP. Informed consent was obtained from patients in the study. At entry, basic clinical (age, comorbidity, symptoms and physical findings) and laboratory (white blood cell count) information commonly used by clinicians in the management of respiratory infections, was recorded. According to microbiological results, patients were assigned to the following categories: bacterial (Streptococcus pneumoniae and other pyogenic bacteria), virus-like (Mycoplasma pneumoniae, Chlamydia spp and virus) and unknown pneumonia. A scoring system to identify the aetiology was derived from the odds ratio (OR) assigned to independent variables, adjusted by a logistic regression model. The accuracy of the prediction rule was tested by using receiver operating characteristic curves.One hundred and three consecutive patients were classified as having virus-like (48), bacterial (37) and unknown (18) pneumonia, respectively. Independent predictors related to bacterial pneumonia were an acute onset of symptoms (OR 31; 95% Cl, 6–150), age greater than 65 or comorbidity (OR 6·9; 95% Cl, 2–23), and leukocytosis or leukopenia (OR 2; 95% Cl, 0·6–7). The sensitivity and specificity of the scoring system to identify patients with bacterial pneumonia were 89% and 94%, respectively. The prediction rule developed from these three variables classified the aetiology of pneumonia with a ROC curve area of 0·84.Proper use of basic clinical and laboratory information is useful to identify the aetiology of CAP. The prediction rule may help clinicians to choose initial antibiotic therapy

    Caffeine Encapsulation in Metal Organic Framework MIL-53(Al) at Pilot Plant Scale for Preparation of Polyamide Textile Fibers with Cosmetic Properties

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    Currently in the marketplace, we can find clothing items able to release skin-friendly ingredients while wearing them. These innovative products with high-added value are based on microencapsulation technology. In this work, due to its lightness, flexibility, porosity, chemical affinity and adsorption capacity, metal-organic framework (MOF) MIL-53(Al) was the selected microcapsule to be synthesized at a large scale and subsequent caffeine encapsulation. The synthesis conditions (molar ratio of reactants, solvents used, reaction time, temperature, pressure reached in the reactor and activation treatment to enhance the encapsulation capacity) were optimized by screening various scaling-up reactor volumes (from lab-scale of 40 mL to pilot plant production of 3.75 L). Two types of Al salts (Al(NO3)3·9H2O from the original recipe and Al2(SO4)3 as commercial SUFAL 8.2) were employed. The liporeductor cosmetic caffeine was selected as the active molecule for encapsulation. Caffeine (38 wt %) was incorporated in CAF@MIL-53(Al) microcapsules, as analyzed by TGA and corroborated by GC/MS and UV-vis after additive extraction. CAF@MIL-53(Al) microcapsules showed a controlled release of caffeine during 6 days at 25 °C (up to 22% of the initial caffeine). These capsules were incorporated through an industrial spinning process (with temperatures up to 260 °C) to manufacture PA-6 fibers with cosmetic properties. Up to 0.7 wt % of capsules were successfully incorporated into the fibers hosting 1700 ppm of caffeine. Fabrics were submitted to scouring, staining, and washing processes, detecting the presence of caffeine in the cosmetic fiber. © 2022 The Authors. Published by American Chemical Society

    Study of Melamine-Formaldehyde/Phase Change Material Microcapsules for the Preparation of Polymer Films by Extrusion

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    n-Eicosane-melamine formaldehyde microcapsules of an average size of 1.1 µm and latent heat of fusion of 146.2 ± 5.3 J/g have been prepared. They have been characterized by scanning electron microscopy, FTIR spectroscopy, calorimetric techniques, and thermogravimetric analyses. Under processing conditions, the microcapsules apparently preserved their properties, also maintaining their n-eicosane loading and heat storage capacity under washing conditions (water with detergent at 60¿C). The microcapsules synthesis has been scaled up for the fabrication of functional films by extrusion. For that, polymer films containing 10 wt.% of microcapsules were prepared at a pilot plant level. In those films, even though a fraction of the n-eicosane loading was lost during the extrusion process, the microcapsules showed good compatibility within the polyamide. The percentage of PCM in the polyamide 6 films was estimated by TGA, verifying also the heat storage capacity predicted by DSC (2.6 ± 0.7 J/g). © 2022 by the authors. Licensee MDPI, Basel, Switzerland

    Theoretical analysis of the focusing of acoustic waves by two-dimensional sonic crystals

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    Motivated by a recent experiment on acoustic lenses, we perform numerical calculations based on a multiple scattering technique to investigate the focusing of acoustic waves with sonic crystals formed by rigid cylinders in air. The focusing effects for crystals of various shapes are examined. The dependance of the focusing length on the filling factor is also studied. It is observed that both the shape and filling factor play a crucial role in controlling the focusing. Furthermore, the robustness of the focusing against disorders is studied. The results show that the sensitivity of the focusing behavior depends on the strength of positional disorders. The theoretical results compare favorably with the experimental observations, reported by Cervera, et al. (Phys. Rev. Lett. 88, 023902 (2002)).Comment: 8 figure

    Effect of animal mixing as a stressor on biomarkers of autophagy and oxidative stress during pig muscle maturation

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    The objective of this work was to study the postmortem evolution of potential biomarkers of autophagy (Beclin 1, LC3-II/LC3-I ratio) and oxidative stress (total antioxidant activity, TAA; superoxide dismutase activity, SOD and catalase activity, CAT) in the Longissimus dorsi muscle of entire male ((Large White × Landrace) × Duroc) pigs subjected to different management treatments that may promote stress, such as mixing unfamiliar animals at the farm and/or during transport and lairage before slaughter. During the rearing period at the farm, five animals were never mixed after the initial formation of the experimental groups (unmixed group at the farm, UF), whereas 10 animals were subjected to a common routine of being mixed with unfamiliar animals (mixed group at the farm, MF). Furthermore, two different treatments were used during the transport and lairage before slaughter: 10 pigs were not mixed (unmixed group during transport and lairage, UTL), whereas five pigs were mixed with unfamiliar animals on the lorry and during lairage (mixed group during transport and lairage, MTL). These mixing treatments were then combined into three pre-slaughter treatments – namely, UF-UTL, MF-UTL and MF-MTL. The results show that MF-UTL and MF-MTL increased significantly the muscle antioxidant defense (TAA, SOD and CAT) at short postmortem times (4 and 8 h; P < 0.001), followed by an earlier depletion of the antioxidant activity at 24 h postmortem (P < 0.05). We also found that mixing unfamiliar animals, both at the farm and during transport and lairage, triggers postmortem muscle autophagy, which showed an earlier activation (higher expression of Beclin 1 and LC3-II/LC3-I ratio at 4 h postmortem followed by a decreasing pattern of this ratio along first 24 h postmortem) in the muscle tissues of animals from the MF-UTL and MF-MTL groups, as an adaptive strategy of the muscle cells for counteracting induced stress. From these results, we propose that monitoring the evolution of the main biomarkers of autophagy (Beclin 1, LC3-II/LC3-I ratio) and muscle antioxidant defense (TAA, SOD, CAT) in the muscle tissue within the first 24 h postmortem may help the detection of animal stress and its potential effect on the postmortem muscle metabolism.info:eu-repo/semantics/publishedVersio
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