1,801 research outputs found

    A Microscopic Energy- and Density-Dependent Effective Interaction and its Test by Nucleus-Nucleus Scattering

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    An effective nucleon-nucleon interaction calculated in nuclear matter from the Bonn potential has been parametrized in terms of a local density- and energy-dependent two-body interaction. This allows to calculate the real part of the nucleus-nucleus scattering potential and to test this effective interaction over a wide region of densities (ŌĀ‚ȧ3ŌĀ0\rho \leq 3\rho_0) produced dynamically in scattering experiments. Comparing our calculations with empirical potentials extracted from data on light and heavy ion scattering by model-unrestricted analysis methods, we find quantitative agreement with the exception of proton scattering. The failure in this case may be traced back to the properties of the effective interaction at low densities, for which the nuclear matter results are not reliable. The success of the interaction at high overlap densities confirms the empirical evidence for a soft equation of state for cold nuclear matter.Comment: 8 pages 3 Figures included, to appear in Phys. Lett.

    Perspectives of vets on plastics in veterinary medicine

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    The use of disposable plastics and their subsequent environmental impacts are topics of increasing concern in modern society. Medical, including veterinary, sectors are major contributors to plastic waste production. While there is an existing body of literature on the use and reduction of disposable plastics in the human medical sector, few studies, if any, have specifically investigated the use of plastics within the veterinary field. The overall aim of this pilot study was to investigate Australian veterinarians regarding their attitudes toward the ways in which they use disposable plastic in their work and personal lives

    Protoplanetary and Transitional Disks in the Open Stellar Cluster IC 2395

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    We present new deep UBVRI images and high-resolution multi-object optical spectroscopy of the young (~ 6 - 10 Myr old), relatively nearby (800 pc) open cluster IC 2395. We identify nearly 300 cluster members and use the photometry to estimate their spectral types, which extend from early B to middle M. We also present an infrared imaging survey of the central region using the IRAC and MIPS instruments on board the Spitzer Space Telescope, covering the wavelength range from 3.6 to 24 microns. Our infrared observations allow us to detect dust in circumstellar disks originating over a typical range of radii ~ 0.1 to ~ 10AU from the central star. We identify 18 Class II, 8 transitional disk, and 23 debris disk candidates, respectively 6.5%, 2.9%, and 8.3% of the cluster members with appropriate data. We apply the same criteria for transitional disk identification to 19 other stellar clusters and associations spanning ages from ~ 1 to ~ 18 Myr. We find that the number of disks in the transitional phase as a fraction of the total with strong 24 micron excesses ([8] - [24] > 1.5) increases from 8.4 +\- 1.3% at ~ 3 Myr to 46 +\- 5% at ~ 10 Myr. Alternative definitions of transitional disks will yield different percentages but should show the same trend.Comment: accepted by the Astrophysical Journa

    Scheduling of eccentric lower limb injury prevention exercises during the soccer micro-cycle: Which day of the week?

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    Scheduling eccentric-based injury prevention programs (IPP) during the common 6-day micro-cycle in soccer is challenged by recovery and tapering phases. This study profiled muscle damage, neuromuscular performance, and perceptual responses to a lower limb eccentric-based IPP administered 1 (MD+1) vs 3 days (MD+3) postmatch. A total of 18 semi-professional players were monitored daily during 3 in-season 6-day micro-cycles, including weekly competitive fixtures. Capillary creatine kinase concentration (CK), posterior lower limb isometric peak force (PF), counter-movement jump (CMJ) performance, and muscle soreness were assessed 24 hours prior to match-day (baseline), and every 24 hours up to 120 hours postmatch. The IPP consisted of lunges, single stiff leg dead-lifts, single leg-squats, and Nordic hamstring exercises. Performing the IPP on MD+1 attenuated the decline in CK normally observed following match play (CON: 142%; MD+3: 166%; small differences). When IPP was delivered on MD+3, CK was higher vs CON and MD+1 trials on both MD+4 (MD+3: 260%; CON: 146%; MD+1: 151%; moderate differences) and MD+5 (MD+3: 209%; CON: 125%; MD+1: 127%; small differences). Soreness ratings were not exacerbated when the IPP was delivered on MD+1, but when prescribed on MD+3, hamstring soreness ratings remained higher on MD+4 and MD+5 (small differences). No between-trial differences were observed for PF and CMJ. Administering the IPP in the middle of the micro-cycle (MD+3) increased measures of muscle damage and soreness, which remained elevated on the day prior to the next match (MD+5). Accordingly, IPP should be scheduled early in the micro-cycle, to avoid compromising preparation for the following match

    Syntheses and NMR and XRD studies ofcarbohydrate‚Äďferrocene conjugates

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    Carbohydrate‚Äďferrocene conjugates were synthesized and showed that the ferrocene entity appeared to be confined to a low volume so that proton NMR spectroscopy revealed 3 to 4 signals for substituted cyclopentadienyl instead of two usually

    Fostering European Collaborations: EUFRAT and work done at the accelerator facilities of JRC-IRMM

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    The European Commission via the General Directorate RTD in its different Framework Programs supported collaborations of member state institutions dealing with nuclear data. The projects EFNUDAT, ERINDA, CHANDA and EUFRAT all have in common Transnational Access Activities (TAA) to partner institutions. Within the past 10 years the collaborations have grown and in CHANDA now 35 partners are involved of which 16 offer TAA to their facilities. Since June 2014 JRC-IRMM, one of the driving forces behind the TAA, launched its own TAA project EUFRAT to foster collaborations with member states institutions. The calls for proposals are open ended with a deadline twice a year. A Project Advisory Committee discusses the proposals and decides on about approval. Financial support is given to approved proposals for two scientists. So far two calls have been evaluated with a request for access totalling more than 5000 h. Examples of proposals at the accelerator facilities at the JRC-IRMM are presented showing the multitude of possibilities using the nuclear facilities at the JRC-IRMM

    Voltage Sensor Probes (VSPs) as an Efficient Tool to Screen for Inhibitors of Voltage-Gated Sodium Channels

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    Voltage-gated sodium channels (Nav) represent a therapeutically validated group of targets for the development of antiepileptic drugs, analgesics and antiarrhythmics [1]. However most of the existing drugs acting as Nav blockers suffer from multiple side effects, but the existence of a multigene family of Nav [2] suggests that the identification of new compounds that selectively block Nav isoforms might have better therapeutic efficiency and reduced side effects. Due to their molecular interference with numerous ion channels, alkaloids represent a group of natural products of particular interest. This is the reason why we have evaluated the efficiency of an in-house method to screen a library of isoquinoline alkaloids formerly isolated in our laboratory. Mammalian GH3 cells constitutively expressing Nav where used in conjunction with Voltage Sensor Probes (VSPs), the signals being read on a fluorescence plate reader. Thanks to this technique, we were able to precisely detect Nav channels activators or blockers. Among 62 compounds tested, 5 isoquinolines appeared as potent Nav channels inhibitors. References: 1. Salat, K. et al. (2014) EOID 23:1093-1104 2. Yu, F.H. et al (2003) Genome Biol. 4

    Numerical Simulation of Illumination and Thermal Conditions at the Lunar Poles Using LOLA DTMs

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    We are interested in illumination conditions and the temperature distribution within the upper two meters of regolith near the lunar poles. Here, areas exist receiving almost constant illumination near areas in permanent shadow, which were identified as potential exploration sites for future missions. For our study a numerical simulation of the illumination and thermal environment for lunar near-polar regions is needed. Our study is based on high-resolution, twenty meters per pixel and 400 x 400 km large polar Digital Terrain Models (DTMs), which were derived from Lunar Orbiter Laser Altimeter (LOLA) data. Illumination conditions were simulated by synthetically illuminating the LOLA DTMs using the horizon method considering the Sun as an extended source. We model polar illumination for the central 50 x 50 km subset and use it as an input at each time-step (2 h) to evaluate the heating of the lunar surface and subsequent conduction in the sub-surface. At surface level we balance the incoming insolation with the subsurface conduction and radiation into space, whereas in the sub-surface we consider conduction with an additional constant radiogenic heat source at the bottom of our two-meter layer. Density is modeled as depth-dependent, the specific heat parameter as temperature-dependent and the thermal conductivity as depth- and temperature-dependent. We implemented a fully implicit finite-volume method in space and backward Euler scheme in time to solve the one-dimensional heat equation at each pixel in our 50 x 50 km DTM. Due to the non-linear dependencies of the parameters mentioned above, Newton's method is employed as the non-linear solver together with the Gauss-Seidel method as the iterative linear solver in each Newton iteration. The software is written in OpenCL and runs in parallel on the GPU cores, which allows for fast computation of large areas and long time scales

    Screening an in house alkaloids library using Voltage-Sensor Probes for new modulators of voltage-gated sodium channels

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    Voltage-gated sodium channels (Nav) are molecular targets of clinically used drugs for treatments of various diseases (epilepsy, chronic pain, cardiac arrhythmia…) and also of numerous animal and plant neurotoxins. The development of easy-to-use screening assays for searching new ligands from chemicals libraries, animal venoms or plant extracts represents a challenge of a great interest to generate therapeutic hits. Here, we used the mammalian GH3B6 pituitary cell line, which constitutively expresses three different neuronal Nav channel isoforms (Nav1.2, Nav1.3 and Nav1.6), to identify novel compounds of pharmacological interest from a library of in-house vegetal alkaloids. The screening is based on a method using Voltage-Sensor Probes (VSPs) that we adapted to detect both activators and blockers of Nav channels. Over the 84 pure alkaloids or plant extracts that were screened, 17 increased the VSP signal. They operated as gating modifier, showing an action mechanism similar to that of batrachotoxin (BTX), known to strongly inhibit Nav channel inactivation. The remaining 67 plant products were assessed for their potency to inhibit BTX-induced VSP signal. We further selected 11 alkaloids as efficient Nav channels inhibitors. We focused our attention on two structural analogs belonging to the aporphine family, liriodenine and oxostephanine, which differ only by a methoxy group. Whereas liriodenine has been already described as a Nav channels blocker, oxostephanine has not been yet documented as an ion channel modulator. In conclusion, the novel VSPs-based screening assay we developed is a suitable method to challenge the discovery and to assess the activity of novel ligands on Nav channels
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