117 research outputs found
Neural-powered unit disk graph embedding: qubits connectivity for some QUBO problems
Graph embedding is a recurrent problem in quantum computing, for instance, quantum annealers need to solve a minor graph embedding in order to map a given Quadratic Unconstrained Binary Optimization (QUBO) problem onto their internal connectivity pattern. This work presents a novel approach to constrained unit disk graph embedding, which is encountered when trying to solve combinatorial optimization problems in QUBO form, using quantum hardware based on neutral Rydberg atoms. The qubits, physically represented by the atoms, are excited to the Rydberg state through laser pulses. Whenever qubits pairs are closer together than the blockade radius, entanglement can be reached, thus preventing entangled qubits to be simultaneously in the excited state. Hence, the blockade radius determines the adjacency pattern among qubits, corresponding to a unit disk configuration. Although it is straight-forward to compute the adjacency pattern given the qubits' coordinates, identifying a feasible unit disk arrangement that matches the desired QUBO matrix is, on the other hand, a much harder task. In the context of quantum optimization, this issue translates into the physical placement of the qubits in the 2D/3D register to match the machine's Ising-like Hamiltonian with the QUBO formulation of the optimization problems. The proposed solution exploits the power of neural networks to transform an initial embedding configuration, which does not match the quantum hardware requirements or does not account for the unit disk property, into a feasible embedding properly representing the target optimization problems. Experimental results show that this new approach overcomes in performance Gurobi solver
Increasing pattern recognition accuracy for chemical sensing by evolutionary based drift compensation
Artificial olfaction systems, which mimic human olfaction by using arrays of gas chemical sensors combined with pattern recognition methods, represent a potentially low-cost tool in many areas of industry such as perfumery, food and drink production, clinical diagnosis, health and safety, environmental monitoring and process control. However, successful applications of these systems are still largely limited to specialized laboratories. Sensor drift, i.e., the lack of a sensor's stability over time, still limits real in dustrial setups. This paper presents and discusses an evolutionary based adaptive drift-correction method designed to work with state-of-the-art classification systems. The proposed approach exploits a cutting-edge evolutionary strategy to iteratively tweak the coefficients of a linear transformation which can transparently correct raw sensors' measures thus mitigating the negative effects of the drift. The method learns the optimal correction strategy without the use of models or other hypotheses on the behavior of the physical chemical sensors
Accelerating legacy applications with spatial computing devices
Heterogeneous computing is the major driving factor in designing new energy-efficient high-performance computing systems. Despite the broad adoption of GPUs and other specialized architectures, the interest in spatial architectures like field-programmable gate arrays (FPGAs) has grown. While combining high performance, low power consumption and high adaptability constitute an advantage, these devices still suffer from a weak software ecosystem, which forces application developers to use tools requiring deep knowledge of the underlying system, often leaving legacy code (e.g., Fortran applications) unsupported. By realizing this, we describe a methodology for porting Fortran (legacy) code on modern FPGA architectures, with the target of preserving performance/power ratios. Aimed as an experience report, we considered an industrial computational fluid dynamics application to demonstrate that our methodology produces synthesizable OpenCL codes targeting Intel Arria10 and Stratix10 devices. Although performance gain is not far beyond that of the original CPU code (we obtained a relative speedup of x 0.59 and x 0.63, respectively, for a single optimized main kernel, while only on the Stratix10 we achieved x 2.56 by replicating the main optimized kernel 4 times), our results are quite encouraging to drawn the path for further investigations. This paper also reports some major criticalities in porting Fortran code on FPGA architectures
Frequency-modulated electromagnetic neural stimulation (FREMS) as a treatment for symptomatic diabetic neuropathy: results from a double-blind, randomised, multicentre, long-term, placebo-controlled clinical trial
AIMS/HYPOTHESIS: The aim was to evaluate the efficacy and safety of
transcutaneous frequency-modulated electromagnetic neural stimulation (frequency
rhythmic electrical modulation system, FREMS) as a treatment for symptomatic
peripheral neuropathy in patients with diabetes mellitus.
METHODS: This was a double-blind, randomised, multicentre, parallel-group study
of three series, each of ten treatment sessions of FREMS or placebo administered
within 3 weeks, 3 months apart, with an overall follow-up of about 51 weeks. The
primary endpoint was the change in nerve conduction velocity (NCV) of deep
peroneal, tibial and sural nerves. Secondary endpoints included the effects of
treatment on pain, tactile, thermal and vibration sensations. Patients eligible
to participate were aged 18-75 years with diabetes for ≥ 1 year, HbA(1c) <11.0%
(97 mmol/mol), with symptomatic diabetic polyneuropathy at the lower extremities
(i.e. abnormal amplitude, latency or NCV of either tibial, deep peroneal or sural
nerve, but with an evocable potential and measurable NCV of the sural nerve), a
Michigan Diabetes Neuropathy Score ≥ 7 and on a stable dose of medications for
diabetic neuropathy in the month prior to enrolment. Data were collected in an
outpatient setting. Participants were allocated to the FREMS or placebo arm (1:1
ratio) according to a sequence generated by a computer random number generator,
without block or stratification factors. Investigators digitised patients' date
of birth and site number into an interactive voice recording system to obtain the
assigned treatment. Participants, investigators conducting the trial, or people
assessing the outcomes were blinded to group assignment.
RESULTS: Patients (n = 110) with symptomatic neuropathy were randomised to FREMS
(n = 54) or placebo (n = 56). In the intention-to-treat population (50 FREMS, 51
placebo), changes in NCV of the three examined nerves were not different between
FREMS and placebo (deep peroneal [means ± SE]: 0.74 ± 0.71 vs 0.06 ± 1.38 m/s;
tibial: 2.08 ± 0.84 vs 0.61 ± 0.43 m/s; and sural: 0.80 ± 1.08 vs -0.91 ± 1.13
m/s; FREMS vs placebo, respectively). FREMS induced a significant reduction in
day and night pain as measured by a visual analogue scale immediately after each
treatment session, although this beneficial effect was no longer measurable 3
months after treatment. Compared with the placebo group, in the FREMS group the
cold sensation threshold was significantly improved, while non-significant
differences were observed in the vibration and warm sensation thresholds. No
relevant side effects were recorded during the study.
CONCLUSIONS/INTERPRETATION: FREMS proved to be a safe treatment for symptomatic
diabetic neuropathy, with immediate, although transient, reduction in pain, and
no effect on NCV.
TRIAL REGISTRATION: ClinicalTrials.gov NCT01628627.
FUNDING: The clinical trial was sponsored by Lorenz Biotech (Medolla, Italy),
lately Lorenz Lifetech (Ozzano dell'Emilia, Italy)
The neutron irradiation module at the European Spallation Source ESS
The neutron Irradiation Module at the European Spallation Source will make use of the high intensity fast neutron spectrum to study the behaviour of the materials used in the facility, set within the ESS research and development program for the target station. By studying how these materials are affected by radiation, estimates of the material degradation in irrradiated bespoke samples will allow to optimise of the design and lifetime of regularly replaced target components. The general design and a set of results from the neutronics calculations, aimed at estimating proton and neutron flux distributions, displacement damage, heat deposition and activation for the radiological hazard analysis of the Irradiation Module, set within the Italian contributions to the ESS construction phase, are reported. © Published under licence by IOP Publishing Ltd
Vitamin-V: Virtual Environment and Tool-boxing for Trustworthy Development of RISC-V based Cloud Services
Vitamin-V is a 2023-2025 Horizon Europe project that aims to develop a complete RISC-V open-source software stack for cloud services with comparable performance to the cloud-dominant x86 counterpart and a powerful virtual execution environment for software development, validation, verification, and test that considers the relevant RISC-V ISA extensions for cloud deployment
Rheological properties of magnetic biogels
We report an experimental and theoretical study of the rheological properties of magnetic biogels
consisting of fibrin polymer networks with embedded magnetite nanoparticles, swollen by aqueous solutions.
We studied two types of magnetic biogels, differenced by the presence or absence of an applied magnetic field
during the initial steps of cross-linking. The experiments demonstrated very strong dependence of the elastic
modulus of the magnetic biogels on the concentration of the magnetic particles. We finally developed some
theoretical models that explain the observed strong concentration effects.This study was supported by projects FIS2013-41821-R (Plan Nacional de Investigación Científica, Desarrollo
e Innovación Tecnológica, MINECO, Spain, co-funded by ERDF, European Union) and FIS2017-85954-R (Ministerio de
Economía, Industria y Competitividad, MINECO, andAgencia Estatal de Investigación, AEI, Spain, co-funded by Fondo Europeo
de Desarrollo Regional, FEDER, European Union). A.Z. is grateful to the program of the Ministry of Education and Science of
the Russian Federation, projects 02.A03.21.0006, 3.1438.2017/4.6, and 3.5214.2017/6.7, as well as to the Russian Fund of Basic
Researches, project 18-08-00178
Serum coding and non-coding RNAs as biomarkers of NAFLD and fibrosis severity
BACKGROUND & AIMS:
In patients with non-alcoholic fatty liver disease (NAFLD), liver biopsy is the gold standard to detect non-alcoholic steatohepatitis (NASH) and stage liver fibrosis. We aimed to identify differentially expressed mRNAs and non-coding RNAs in serum samples of biopsy-diagnosed mild and severe NAFLD patients with respect to controls and to each other.
METHODS:
We first performed a whole transcriptome analysis through microarray (n = 12: four Control: CTRL; four mild NAFLD: NAS 64 4 F0; four severe NAFLD NAS 65 5 F3), followed by validation of selected transcripts through real-time PCRs in an independent internal cohort of 88 subjects (63 NAFLD, 25 CTRL) and in an external cohort of 50 NAFLD patients. A similar analysis was also performed on liver biopsies and HepG2 cells exposed to oleate:palmitate or only palmitate (cellular model of NAFL/NASH) at intracellular/extracellular levels. Transcript correlation with histological/clinical data was also analysed.
RESULTS:
We identified several differentially expressed coding/non-coding RNAs in each group of the study cohort. We validated the up-regulation of UBE2V1, BNIP3L mRNAs, RP11-128N14.5 lncRNA, TGFB2/TGFB2-OT1 coding/lncRNA in patients with NAS 65 5 (vs NAS 64 4) and the up-regulation of HBA2 mRNA, TGFB2/TGFB2-OT1 coding/lncRNA in patients with Fibrosis stages = 3-4 (vs F = 0-2). In in vitro models: UBE2V1, RP11-128N14.5 and TGFB2/TGFB2-OT1 had an increasing expression trend ranging from CTRL to oleate:palmitate or only palmitate-treated cells both at intracellular and extracellular level, while BNIP3L was up-regulated only at extracellular level. UBE2V1, RP11-128N14.5, TGFB2/TGFB2-OT1 and HBA2 up-regulation was also observed at histological level. UBE2V1, RP11-128N14.5, BNIP3L and TGFB2/TGFB2-OT1 correlated with histological/biochemical data. Combinations of TGFB2/TGFB2-OT1 + Fibrosis Index based on the four factors (FIB-4) showed an Area Under the Curve (AUC) of 0.891 (P = 3.00E-06) or TGFB2/TGFB2-OT1 + Fibroscan (AUC = 0.892, P = 2.00E-06) improved the detection of F = 3-4 with respect to F = 0-2 fibrosis stages.
CONCLUSIONS:
We identified specific serum coding/non-coding RNA profiles in severe and mild NAFLD patients that possibly mirror the molecular mechanisms underlying NAFLD progression towards NASH/fibrosis. TGFB2/TGFB2-OT1 detection improves FIB-4/Fibroscan diagnostic performance for advanced fibrosis discrimination
The instrument suite of the European Spallation Source
An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of the
European Spallation Source (ESS), and being made available to the neutron user community. The ESS neutron
source consists of a high-power accelerator and target station, providing a unique long-pulse time structure
of slow neutrons. The design considerations behind the time structure, moderator geometry and instrument
layout are presented.
The 15-instrument suite consists of two small-angle instruments, two reflectometers, an imaging beamline,
two single-crystal diffractometers; one for macromolecular crystallography and one for magnetism, two powder
diffractometers, and an engineering diffractometer, as well as an array of five inelastic instruments comprising
two chopper spectrometers, an inverse-geometry single-crystal excitations spectrometer, an instrument for vibrational
spectroscopy and a high-resolution backscattering spectrometer. The conceptual design, performance
and scientific drivers of each of these instruments are described.
All of the instruments are designed to provide breakthrough new scientific capability, not currently
available at existing facilities, building on the inherent strengths of the ESS long-pulse neutron source of high
flux, flexible resolution and large bandwidth. Each of them is predicted to provide world-leading performance
at an accelerator power of 2 MW. This technical capability translates into a very broad range of scientific
capabilities. The composition of the instrument suite has been chosen to maximise the breadth and depth
of the scientific impact o
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