572 research outputs found

    Anomalous material-dependent transport of focused, laser-driven proton beams.

    Get PDF
    Intense lasers can accelerate protons in sufficient numbers and energy that the resulting beam can heat materials to exotic warm (10 s of eV temperature) states. Here we show with experimental data that a laser-driven proton beam focused onto a target heated it in a localized spot with size strongly dependent upon material and as small as 35 μm radius. Simulations indicate that cold stopping power values cannot model the intense proton beam transport in solid targets well enough to match the large differences observed. In the experiment a 74 J, 670 fs laser drove a focusing proton beam that transported through different thicknesses of solid Mylar, Al, Cu or Au, eventually heating a rear, thin, Au witness layer. The XUV emission seen from the rear of the Au indicated a clear dependence of proton beam transport upon atomic number, Z, of the transport layer: a larger and brighter emission spot was measured after proton transport through the lower Z foils even with equal mass density for supposed equivalent proton stopping range. Beam transport dynamics pertaining to the observed heated spot were investigated numerically with a particle-in-cell (PIC) code. In simulations protons moving through an Al transport layer result in higher Au temperature responsible for higher Au radiant emittance compared to a Cu transport case. The inferred finding that proton stopping varies with temperature in different materials, considerably changing the beam heating profile, can guide applications seeking to controllably heat targets with intense proton beams

    Reprint of “Atlantic Multidecadal Oscillation (AMO) modulates dynamics of small pelagic fishes and ecosystem regime shifts in the eastern North and Central Atlantic”

    Get PDF
    Dynamics of abundance and migrations of populations of small pelagic clupeoid fish such as anchovy (Engraulis encrasicolus), sardine (Sardina pilchardus), sardinella (Sardinella aurita), sprat (Sprattus sprattus) and herring (Clupea harengus) in the eastern North and Central Atlantic between Senegal and Norway vary in synchrony with the warm and cool phases of the Atlantic Multidecadal Oscillation (AMO). This is shown by compiling retrospective data on fish catches and anecdotal observations, which in some cases date back to the mid-19th century. The AMO is defined as the de-trended mean of North Atlantic (0-60 degrees N) sea surface temperature anomalies. However, it is not primarily the temperature which drives the dynamics of the small pelagic fish populations. Instead, the AMO seems to be a proxy for complex processes in the coupled atmosphere-ocean system of the North Atlantic. This is manifested in large-scale changes in strength and direction of the current system that move water masses around the North Atlantic and likely involves the North Atlantic Oscillation (NAO), the Atlantic Meridional Overturning Circulation (AMOC), the Mediterranean Overflow Water (MOW) and the subpolar gyre (SPG). The contractions and expansions of the SPG apparently play a key role. This was particularly obvious in the mid-1990s, when the SPG abruptly contracted with the result that warm subtropical water masses moved to the north and east. Small pelagic fish populations in the eastern North and Central Atlantic, including those in the Mediterranean responded quickly by changing abundances and migrating northwards. It seems that the complex ocean-atmosphere changes in the mid-1990s, which are described in the text in detail, caused a regime shift in the ecosystems of the eastern North and Central Atlantic and the small pelagic clupeoid fish populations are the sentinels of this shift

    Study of the cheese salting process by dielectric properties at microwave frequencies

    Full text link
    [EN] The salting process involves complex phenomena that affect the overall quality of cheese due to its effect on water activity and induced biochemical changes. The permittivity of cheese was analysed throughout the cheese salting treatment in order to relate it to water and salt transport. The salting treatment was carried out using 25% (wily) sodium chloride brine at 4 degrees C. The samples were immersed in a vessel containing the osmotic solution with continuous stirring, for 0, 10, 20, 30, 40, 50, 60, 90, 120, 180, 240, 360, 480, 720, 900 and 1440 min. Samples were subsequently equilibrated in an isothermal chamber at 4 degrees C for 24 h. Mass, volume, surface water activity, moisture, ion content and permittivity were determined in fresh and salted samples. Permittivity was measured from 500 MHz to 20 GHz, using an openended coaxial probe connected to a Vector Network Analyser. The results showed that measurements at 20 GHz explain the water loss and water flux in the overall product. The state of the electrolytes in cheese can be followed using the ionic conductivity at 500 MHz. A coupled measurement of permittivity at 20 GHz and 500 MHz can predict the chemical species involved in the cheese salting process, and its structural changes. In conclusion, the measurement of permittivity in the microwave range can be used to monitor the salting cheese process. (C) 2018 Elsevier Ltd. All rights reserved.The authors acknowledge financial support from the Spanish Ministerio de Economia, Industria y Competitividad, Programa Estatal de I+D+i orientada a los Retos de la Sociedad AGL2016-80643-R. Author J. Velazquez-Varela thanks the Consejo Nacional de Ciencia y Tecnologia (CONACyT) of Mexico for its support. This paper was published under the frame of the European Social Fund, Human Resources Development Operational Programme 2007-2013, project no. POSDRU/159/1.5/S/132765.Velazquez-Varela, J.; Castro Giraldez, M.; Cuibus, L.; Tomás-Egea, JÁ.; Socaciu, C.; Fito Suñer, PJ. (2018). Study of the cheese salting process by dielectric properties at microwave frequencies. Journal of Food Engineering. 224:121-128. https://doi.org/10.1016/j.jfoodeng.2017.12.024S12112822

    The Role of Invasive Therapies in Elderly Patients with Acute Myocardial Infarction

    Get PDF
    INTRODUCTION: In elderly patients with acute myocardial infarction, very little is known about the role of surgical myocardial revascularization and percutaneous coronary intervention (invasive therapies - IT), especially in the context of long-term outcomes after hospital discharge. METHODS: We analyzed 1588 patients with MI who had been included prospectively in a databank and followed for up to 7.5 years. In this population, 548 patients were >70 years old (elderly group - EG), and 1040 were <70 years of age (younger group - YG); 1088 underwent IT during hospitalization, and the remaining 500 were treated medically (conservative therapy - CT). Patients were monitored either by visit or by phone at least once a year. A standard questionnaire was administered to all patients. The impact of IT was analyzed with both non-adjusted and adjusted models. RESULTS: By the end of the follow-up period, the survival rates for the IT and CT groups were, respectively, 71.9% versus 47.2% in the global population (hazard ratio=0.55, P<0.001), 81.5% versus 66.6% in the YG (hazard ratio=0.68, P=0.018) and 48.8% versus 20.3% in the EG (hazard ratio=0.58, P<0.001). In the adjusted models, the hazard ratios were 0.62 (P<0.001) in the global population, 0.74 in the YG (P=0.073) and 0.64 (P=0.001) in the EG. CONCLUSION: Long-term follow-up of patients with myocardial infarction revealed that IT during the in-hospital phase was at least as effective in elderly patients as in younger patients

    Información de medicamentos a la población desde el Servicio de Farmacia a través de Internet

    Get PDF
    Objectives: To describe and discuss the work of a Pharmacy Department for the health-care portal www.viatusalud.com. Methods: Using a web portal, a Pharmacy Department develops and updates a vademecum on drugs, and answers enquiries by end-users. Results: On December 31, 2002 more than 750 records on drugs were available, and 3030 enquiries had been answered. Conclusions: With this drug information and online enquiry service, our Pharmacy Department helps meet the demand of health-care information posed by the community and by patients previously seen at Clínica Universitaria. In addition, it allows areas of improvement to be detected in the information to be offered to patients fron a Pharmacy Department, and represents a tertiary source of information for health-care professionals

    Visceral and somatic pain modalities reveal NaV 1.7-independent visceral nociceptive pathways.

    Get PDF
    KEY POINTS: Voltage-gated sodium channels play a fundamental role in determining neuronal excitability. Specifically, voltage-gated sodium channel subtype NaV 1.7 is required for sensing acute and inflammatory somatic pain in mice and humans but its significance in pain originating from the viscera is unknown. Using comparative behavioural models evoking somatic and visceral pain pathways, we identify the requirement for NaV 1.7 in regulating somatic (noxious heat pain threshold) but not in visceral pain signalling. These results enable us to better understand the mechanisms underlying the transduction of noxious stimuli from the viscera, suggest that the investigation of pain pathways should be undertaken in a modality-specific manner and help to direct drug discovery efforts towards novel visceral analgesics. ABSTRACT: Voltage-gated sodium channel NaV 1.7 is required for acute and inflammatory pain in mice and humans but its significance for visceral pain is unknown. Here we examine the role of NaV 1.7 in visceral pain processing and the development of referred hyperalgesia using a conditional nociceptor-specific NaV 1.7 knockout mouse (NaV 1.7Nav1.8 ) and selective small-molecule NaV 1.7 antagonist PF-5198007. NaV 1.7Nav1.8 mice showed normal nociceptive behaviours in response to intracolonic application of either capsaicin or mustard oil, stimuli known to evoke sustained nociceptor activity and sensitization following tissue damage, respectively. Normal responses following induction of cystitis by cyclophosphamide were also observed in both NaV 1.7Nav1.8 and littermate controls. Loss, or blockade, of NaV 1.7 did not affect afferent responses to noxious mechanical and chemical stimuli in nerve-gut preparations in mouse, or following antagonism of NaV 1.7 in resected human appendix stimulated by noxious distending pressures. However, expression analysis of voltage-gated sodium channel α subunits revealed NaV 1.7 mRNA transcripts in nearly all retrogradely labelled colonic neurons, suggesting redundancy in function. By contrast, using comparative somatic behavioural models we identify that genetic deletion of NaV 1.7 (in NaV 1.8-expressing neurons) regulates noxious heat pain threshold and that this can be recapitulated by the selective NaV 1.7 antagonist PF-5198007. Our data demonstrate that NaV 1.7 (in NaV 1.8-expressing neurons) contributes to defined pain pathways in a modality-dependent manner, modulating somatic noxious heat pain, but is not required for visceral pain processing, and advocate that pharmacological block of NaV 1.7 alone in the viscera may be insufficient in targeting chronic visceral pain.University of Granada Dr Hadwen Trust for Humane Researc

    MicroRNAs and Developmental Robustness: A New Layer Is Revealed

    Get PDF
    MicroRNAs provide a new layer of regulation to ensure that a developmental program of programmed cell death yields a reproducible outcome in spite of perturbations to the system

    Robustness and Stability of the Gene Regulatory Network Involved in DV Boundary Formation in the Drosophila Wing

    Get PDF
    Gene regulatory networks have been conserved during evolution. The Drosophila wing and the vertebrate hindbrain share the gene network involved in the establishment of the boundary between dorsal and ventral compartments in the wing and adjacent rhombomeres in the hindbrain. A positive feedback-loop between boundary and non-boundary cells and mediated by the activities of Notch and Wingless/Wnt-1 leads to the establishment of a Notch dependent organizer at the boundary. By means of a Systems Biology approach that combines mathematical modeling and both in silico and in vivo experiments in the Drosophila wing primordium, we modeled and tested this regulatory network and present evidence that a novel property, namely refractoriness to the Wingless signaling molecule, is required in boundary cells for the formation of a stable dorsal-ventral boundary. This new property has been validated in vivo, promotes mutually exclusive domains of Notch and Wingless activities and confers stability to the dorsal-ventral boundary. A robustness analysis of the regulatory network complements our results and ensures its biological plausibility
    corecore