Optimized White Reflectance in Photonic Network Structures

Three-dimensional disordered networks are receiving increasing attention as versatile architectures for highly scattering materials. However, due to their complex morphology, little is still known about the interplay between their structural and optical properties. Here, we describe a simple algorithm that allows to generate photonic network structures inspired by that of the Cyphochilus beetle, famous for the bright white reflectance of its thin cuticular scales. The model allows to vary the degree of structural anisotropy and filling fraction of the network independently, revealing the key contribution of these two parameters to the overall scattering efficiency. Rigorous numerical simulations show that the obtained structures can exceed the broadband reflectance of the beetle while using less material, providing new insights for the design of advanced scattering materials.Comment: 10 pages, 3 figures. peer reviewed version, published in final form at https://doi.org/10.1002/adom.20190004

Effect of Industrial Heat Treatment and Barrel Finishing on the Mechanical Performance of Ti6Al4V Processed by Selective Laser Melting

Additive manufacturing is now capable of delivering high-quality, complex-shaped metallic components. The titanium alloy Ti6Al4V is an example of a printable metal being broadly used for advanced structural applications. A sound characterization of static mechanical properties of additively manufactured material is crucial for its proper application, and here specifically for Ti6Al4V. This includes a complete understanding of the influence of postprocess treatment on the material behavior, which has not been reached yet. In the present paper, the postprocess effects of surface finish and heat treatment on the mechanical performance of Ti6Al4V after selective laser melting were investigated. Some samples were subjected to barrel finishing at two different intensities, while different sets of specimens underwent several thermal cycles. As a reference, a control group of specimens was included, which did not undergo any postprocessing. The treatments were selected to be effective and easy to perform, being suitable for real industrial applications. Tensile tests were performed on all the samples, to obtain yield stress, ultimate tensile strength and elongation at fracture. The area reduction of the barrel-finished samples, after being tested, was measured by using a 3D scanner, as a further indication of ductility. Experimental results are reported and discussed, highlighting the effect of postprocessing treatments on the mechanical response. We then propose the optimal postprocessing procedure to enhance ductility without compromising strength, for structures manufactured from Ti6Al4V with selective laser melting

Recent advances in mathematical modeling and statistical analysis of exocytosis in endocrine cells

open5noMost endocrine cells secrete hormones as a result of Ca(2+)-regulated exocytosis, i.e., fusion of the membranes of hormone-containing secretory granules with the cell membrane, which allows the hormone molecules to escape to the extracellular space. As in neurons, electrical activity and cell depolarization open voltage-sensitive Ca(2+) channels, and the resulting Ca(2+) influx elevate the intracellular Ca(2+) concentration, which in turn causes exocytosis. Whereas the main molecular components involved in exocytosis are increasingly well understood, quantitative understanding of the dynamical aspects of exocytosis is still lacking. Due to the nontrivial spatiotemporal Ca(2+) dynamics, which depends on the particular pattern of electrical activity as well as Ca(2+) channel kinetics, exocytosis is dependent on the spatial arrangement of Ca(2+) channels and secretory granules. For example, the creation of local Ca(2+) microdomains, where the Ca(2+) concentration reaches tens of µM, are believed to be important for triggering exocytosis. Spatiotemporal simulations of buffered Ca(2+) diffusion have provided important insight into the interplay between electrical activity, Ca(2+) channel kinetics, and the location of granules and Ca(2+) channels. By confronting simulations with statistical time-to-event (or survival) regression analysis of single granule exocytosis monitored with TIRF microscopy, a direct connection between location and rate of exocytosis can be obtained at the local, single-granule level. To get insight into whole-cell secretion, simplifications of the full spatiotemporal dynamics have shown to be highly helpful. Here, we provide an overview of recent approaches and results for quantitative analysis of Ca(2+) regulated exocytosis of hormone-containing granules.openPedersen, Morten Gram; Tagliavini, Alessia; Cortese, Giuliana; Riz, Michela; Montefusco, FrancescoPedersen, MORTEN GRAM; Tagliavini, Alessia; Cortese, Giuliana; Riz, Michela; Montefusco, Francesc

Back to Government?: The Pluralistic Deficit in the Decisionmaking Process and Before the Courts

Back to Government?: The Pluralistic Deficit in the Decisionmaking Processes and Before the Courts, Symposium. University of Trento, Italy, June 11-12, 2004

Back to Government?: The Pluralistic Deficit in the Decisionmaking Process and Before the Courts

Back to Government?: The Pluralistic Deficit in the Decisionmaking Processes and Before the Courts, Symposium. University of Trento, Italy, June 11-12, 2004

Excitability of the motor cortex in patients with migraine changes with the time elapsed from the last attack

BACKGROUND: Motor-evoked potentials (MEPs) produced by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex can be an objective measure of cortical excitability. Previously, MEP thresholds were found to be normal, increased, or even reduced in patients with migraine. In the present study, we determined whether the level of cortical excitability changes with the time interval from the last migraine attack, thereby accounting for the inconsistencies in previous reports. METHODS: Twenty-six patients with untreated migraine without aura (MO) underwent a MEP study between attacks. Their data were then compared to the MEP data collected from a group of 24 healthy volunteers (HVs). During the experiment, the TMS figure-of-eight coil was positioned over the left motor area. After identifying the resting motor threshold (RMT), we delivered 10 single TMS pulses (rate: 0.1 Hz, intensity: 120% of the RMT) and averaged the resulting MEP amplitudes. RESULTS: The mean RMTs and MEP amplitudes were not significantly different between the MO and HV groups. In patients with MO, the RMTs were negatively correlated with the number of days elapsed since the last migraine attack (rho = -0.404, p = 0.04). CONCLUSION: Our results suggest that the threshold for evoking MEPs is influenced by the proximity of an attack; specifically, the threshold is lower when a long time interval has passed after an attack, and is higher (within the range of normative values) when measured close to an attack. These dynamic RMT variations resemble those we reported previously for visual and somatosensory evoked potentials and may represent time-dependent plastic changes in brain excitability in relation to the migraine cycle

analysis of the micro voids fraction in structural steels and its evolution during plastic deformation until failure

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Effect of high level of bladder filling on spinal nociception and motoneuronal excitability

To verify whether high level of bladder distension may counteract the inhibitory effect of descending pathways on sacral spinal cord neurons and to investigate which spinal circuitries are possibly involved in such a viscero-somatic interaction. Nociceptive withdrawal reflex (NWR), cutaneous silent period (CSP), and H-reflex were recorded in both lower and upper limbs of twenty-eight healthy subjects. Subjects were examined during baseline (empty bladder, no voiding desire), high level of bladder filling (urgency desire), and control (empty bladder, no voiding desire) sessions. Results showed that the NWR and its related pain perception were reduced in the upper limbs, while only a pain perception reduction in males was observed in the lower limbs. The H-reflex was inhibited in both limbs. No effects were found on the CSP duration. The decrease in both the NWR and its related pain perception in the upper limbs confirms the presence of a bladder distension-induced descending inhibitory modulation on nociception at spinal level. The lack of a similar inhibitory effect in the lower limbs suggests that excitatory nociceptive inputs from bladder afferents counterbalance the inhibitory effect on sacral spinal cord. The lack of the descending inhibitory effect may be a mechanism aimed at forcing the micturition phase to avoid bladder damage caused by bladder sovradistension