The brain's ability to perform efficient and fault-tolerant data processing is strongly related to its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to achieve higher levels of energy efficiency and computational performance. Although efforts to address neuromorphic solutions through hardware based on top-down CMOS-based technologies have obtained interesting results in terms of energetic efficiency improvement, the replication of brain's self-assembled and redundant architectures is not considered in the roadmaps of data processing electronics.
View Article and Find Full Text PDFObjectives: This independent prospective study evaluated the short-term effects and safety of photobiomodulation (PBM) in early and intermediate age-related macular degeneration.
Methods: patients were treated with PBM in one eye. Functional parameters and drusen volume were measured at one (W4), three- (W12) and six-months (W24) after PBM.
The liquid-to-solid phase transition is a complex process that is difficult to investigate experimentally with sufficient spatial and temporal resolution. A key aspect of the transition is the formation of a critical seed of the crystalline phase in a supercooled liquid, that is, a liquid in a metastable state below the melting temperature. This stochastic process is commonly described within the framework of classical nucleation theory, but accurate tests of the theory in atomic and molecular liquids are challenging.
View Article and Find Full Text PDFThe idea of using ultrashort X-ray pulses to obtain images of single proteins frozen in time has fascinated and inspired many. It was one of the arguments for building X-ray free-electron lasers. According to theory, the extremely intense pulses provide sufficient signal to dispense with using crystals as an amplifier, and the ultrashort pulse duration permits capturing the diffraction data before the sample inevitably explodes.
View Article and Find Full Text PDFQuantum simulations of the hydroxide anion and hydroxyl radical are reported, employing variational quantum algorithms for near-term quantum devices. The energy of each species is calculated along the dissociation curve, to obtain information about the stability of the molecular species being investigated. It is shown that simulations restricted to valence spaces incorrectly predict the hydroxyl radical to be more stable than the hydroxide anion.
View Article and Find Full Text PDFPurpose: To compare the 2-year outcome to antivascular endothelial growth factor therapy for myopic choroidal neovascularization (CNV) in the eyes with or without dome-shaped macula (DSM).
Methods: Data from treatment-naive myopic CNV with a 2-year follow-up were retrospectively collected and divided into two groups according to the presence of DSM. The best-corrected visual acuity was acquired at baseline, 3, 12, and 24 months.
Crystallization is a fundamental natural phenomenon and the ubiquitous physical process in materials science for the design of new materials. So far, experimental observations of the structural dynamics in crystallization have been mostly restricted to slow dynamics. We present here an exclusive way to explore the dynamics of crystallization in highly controlled conditions (i.
View Article and Find Full Text PDFPurpose: To evaluate the long-term functional and morphological changes occurring in myopic eyes with a dome-shaped macula (DSM), with or without untreated serous retinal detachment (SRD).
Methods: This prospective, single-centre study enrolled consecutive cases of highly myopic patients with DSM with or without a SRD. Patients underwent complete ophthalmological examinations, optical coherence tomography, axial length measurements and autofluorescence.
Crystallization is a fundamental process in materials science, providing the primary route for the realization of a wide range of new materials. Crystallization rates are also considered to be useful probes of glass-forming ability. At the microscopic level, crystallization is described by the classical crystal nucleation and growth theories, yet in general solid formation is a far more complex process.
View Article and Find Full Text PDFFemtosecond laser pulses have opened new frontiers for the study of ultrafast phase transitions and nonequilibrium states of matter. In this Letter, we report on structural dynamics in atomic clusters pumped with intense near-infrared (NIR) pulses into a nanoplasma state. Employing wide-angle scattering with intense femtosecond x-ray pulses from a free-electron laser source, we find that highly excited xenon nanoparticles retain their crystalline bulk structure and density in the inner core long after the driving NIR pulse.
View Article and Find Full Text PDFThe paper focuses on the development of electron coherent diffraction imaging in transmission electron microscopy, made in the, approximately, last ten years in our collaborative research group, to study the properties of materials at atomic resolution, overcoming the limitations due to the aberrations of the electron lenses and obtaining atomic resolution images, in which the distribution of the maxima is directly related to the specimen atomic potentials projected onto the microscope image detector. Here, it is shown how augmented coherent diffraction imaging makes it possible to achieve quantitative atomic resolution maps of the specimen atomic species, even in the presence of low atomic number atoms within a crystal matrix containing heavy atoms. This aim is achieved by: (i) tailoring the experimental set-up, (ii) improving the experimental data by properly treating parasitic diffused intensities to maximize the measure of the significant information, (iii) developing efficient methods to merge the information acquired in both direct and reciprocal spaces, (iv) treating the dynamical diffused intensities to accurately measure the specimen projected potentials, (v) improving the phase retrieval algorithms to better explore the space of solutions.
View Article and Find Full Text PDFTheory of superfluid ^{4}He shows that, due to strong correlations and backflow effects, the density profile of a vortex line has the character of a density modulation and it is not a simple rarefaction region as found in clouds of cold bosonic atoms. We find that the basic features of this density modulation are represented by a wave packet of cylindrical symmetry in which rotons with a positive group velocity have a dominant role: The vortex density modulation can be viewed as a cloud of virtual excitations, mainly rotons, sustained by the phase of the vortex wave function. This suggests that in a vortex reconnection some of these rotons become real so that a vortex tangle is predicted to be a source of nonthermal rotons.
View Article and Find Full Text PDFIntroduction: Endometriosis is the growth of endometrium outside the uterine cavity. In 5-15% of cases the disease can affect the colon and small bowel, causing complete obstruction and requiring resection in about 1% of cases.
Case Summary: We describe a case of sigmoid obstruction due to endometriosis in a 38 years old woman with personal history of endometriosis.
We consider a zero-temperature one-dimensional system of bosons interacting via the soft-shoulder potential in the continuum, typical of dressed Rydberg gases. We employ quantum Monte Carlo simulations, which allow for the exact calculation of imaginary-time correlations, and a stochastic analytic continuation method, to extract the dynamical structure factor. At finite densities, in the weakly interacting homogeneous regime, a rotonic spectrum marks the tendency to clustering.
View Article and Find Full Text PDFCoherent Diffractive Imaging is a lensless technique that allows imaging of matter at a spatial resolution not limited by lens aberrations. This technique exploits the measured diffraction pattern of a coherent beam scattered by periodic and non-periodic objects to retrieve spatial information. The diffracted intensity, for weak-scattering objects, is proportional to the modulus of the Fourier Transform of the object scattering function.
View Article and Find Full Text PDFJ Phys Condens Matter
November 2013
This article discusses the behavior of submonolayer quantum films (He and H2) on graphene and newly discovered surfaces that are derived from graphene. Among these substrates are graphane (abbreviated GH), which has an H atom bonded to each C atom, and fluorographene (GF). The subject is introduced by describing the related problem of monolayer films on graphite.
View Article and Find Full Text PDFWe hereby report a case of use of biological mesh to repair one large, contaminated abdominal wall defect due to a sigmoid tumour presented as an abscess infiltrating the abdominal wall. Our patient was a 48-year-old woman. Her medical history was negative for any previous disease or surgical procedure.
View Article and Find Full Text PDFBACKGROUND: Paget's disease (PD) of the breast is a relatively rare condition (incidence 1-3%) among primary breast cancers [6]. It presents with suggestive symptoms like erythema, nipple bleeding and ulceration. PATIENT AND METHODS: A 76-year-old woman was followed up for cancer of the left breast that had been operated 10 years before.
View Article and Find Full Text PDFObjective: The aim of this study was to evaluate the robustness and zero-drift of an intracranial pressure sensor, Neurovent-P (Raumedic AG, Münchberg, Germany), when used in the clinical environment.
Methods: A prospective multicenter trial, conforming to the International Organization for Standardization 14155 Standard, was conducted in 6 European BrainIT centers between July 2005 and December 2006. Ninety-nine catheters were used.