1,761 research outputs found
Neural Nets and Star/Galaxy Separation in Wide Field Astronomical Images
One of the most relevant problems in the extraction of scientifically useful
information from wide field astronomical images (both photographic plates and
CCD frames) is the recognition of the objects against a noisy background and
their classification in unresolved (star-like) and resolved (galaxies) sources.
In this paper we present a neural network based method capable to perform both
tasks and discuss in detail the performance of object detection in a
representative celestial field. The performance of our method is compared to
that of other methodologies often used within the astronomical community.Comment: 6 pages, to appear in the proceedings of IJCNN 99, IEEE Press, 199
AMPHIPHILIC, BIODEGRADABLE ANDBIOCOMPATIBLE POLYMERS FOR INDUSTRIALAPPLICATIONS
The aim of this PhD work was to establish the synthetic procedures for new families of biocompatible and biodegradable and/or bioeliminable biomaterials that can be differently processed to obtain nanoparticles, core-shell nanofibres and hydrogel slabs or conduits, respectively. Depending on composition, size and morphology, these biomaterials may be intended for applications as drug delivery systems and/or tissue regeneration.
Specifically, the research project has been developed along two main lines:
\u2022 Synthesis of poly(lactic-glycolic acid)-g-poly(1-vinylpyrrolidin-2-one) (PLGA-g-PVP) copolymers whose architecture consisted of a long PLGA backbone with oligomeric PVP pendants. These were obtained by the radical polymerisation of 1-vinylpyrrolidin-2-one in molten PLGA 50:50, acting as chain transfer agent. The procedure was a single pot - single step one. Copolymers were characterized by FTIR, 1H- and 13C-NMR and thermal analyses. They were saponified giving, besides PLGA degradation products, also un-degraded PVP. This was isolated and analysed by size exclusion chromatography, to evaluate the molecular weights of grafted PVP chains. MALDI-TOF analysis allowed identifying the chemical structure of PVP terminals and unambiguously establishing that PVP chains had been grafted onto PLGA backbone
PLGA-g-PVP with different PVP content were formulated as drug nanocarriers by different procedures. Doxorubicin-loaded nanoparticles were prepared by the solvent diffusion method and fully characterised. In vitro drug release kinetics were studied and in vitro biological activity evaluated on several antitumoral cell lines.
PLGA-g-PVP were also used as coatings of lipid nanocapsules for the delivery of curcumin and artemisinin as antimalarials. Drug loaded-lipid micro-dispersions were first prepared by oil in water emulsion. The lipid drops were converted into nanometric ones by high pressure homogenization and finally surface coated by adding a DMSO/acetone PLGA-g-PVP solution. Growth inhibition assay were conducted on plasmodium falciparum (3D7) cultures. Haemoltic assays were conducted on healthy red blood cells.
PLGA-g-PVP- and PLGA-based scaffolds consisting of nanofibrous mats were produced by electrospinning. Starting materials were electrospun and their morphology was evaluated by scanning electron microscopy and wettability by contact angle measurements. Coaxial electrospinning of two materials, in which PLGA formed the core and PLGA-g-PVP the shell of fibres, were also conducted and compared with those obtained by mixed solutions of staritng materials. Chemical composition was evaluated by TGA, morphology by scanning electron microscopy and wettability by contact angle measurements. Nanofabric scaffold produced will be evaluated for drug release and tissue engineering applications.
\u2022 Synthesis of a new classes of poly(saccharide)-poly(aminoamine)s 3D-network intended as scaffolds for the regeneration of liver.
In particular, hyaluronic acid-polyamidoamine and hyaluronic acid-gelatin- polyamidoamine hydrogels were synthesised by amidation reaction between the carboxylic acid group of hyaluronic acid and amine groups of gelatin and or an NH2-functionalized PAA, promoted by 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) as coupling agent. Chemical-physical characterization were carried out on hydrogels. In order to promote hepatic cell proliferation serotonin was bonded to both hydrogels, adding it to the initial recipe, exploiting the above reaction between carboxylic acid group of hyaluronic acid and amine group of serotonin. Serotonin-loaded hydrogels were tested in vitro to evaluate biological efficacy
Editorial: Endocrine modulators of neurological processes: potential treatment targets of pediatric neurological diseases.
Editorial on the Research Topic Endocrine Modulators of Neurological Processes: Potential Treatment Targets of Pediatric
Neurological Diseases
Lossy Multi/Hyperspectral Compression HW Implementation at high data rate
Image compression is becoming more and more important, as new multispectral and hyperspectral instruments are going to generate very high data rates due to the increased spatial and spectral resolutions. Transmitting all the acquired data to the ground segment is a serious bottleneck, and compression techniques are a feasible solution to this problem. The CCSDS has established a working group (WG) on multispectral and Hyperspectral Data Compression (MHDC), which has the purpose of standardizing compression techniques to be used onboard. The WG has already standardized a lossless compression algorithm for multispectral and hyperspectral images, and has started working on a lossy compression algorithm. The complexity of lossless compression algorithms is typically larger than that of lossy ones, leading to potentially lower throughputs. Therefore, a careful assessment is required in order to identify techniques that are able to sustain very high data rates. The increased complexity can also lead to increased resource occupancy on a hardware device such as an FPGA. Lossy compression introduces information losses in the images, and these losses must be accurately characterized, and their effect on the applications investigated. For these reasons, developing a lossy algorithm requires a more elaborate process. Under an ESA contract primed by Politecnico of Torino, TSD is currently designing an IP core for FPGA and/or ASIC implementation of a lossy compression algorithm that is being proposed for CCSDS standardization. In addition to the IP core, TSD is developing a HW platform based on the Xilinx Virtex-5 XQR5VFX130, the industry's first high performance rad-hard reconfigurable FPGA for processing-intensive for space systems. Advanced results along with details of electronic platform design will be presented in this paper
Chlamydophila pecorum in fetuses of mediterranean buffalo (bubalus bubalis) bred in Italy
In order to study the role played by the different species of Chlamydophila in causing abortions in Mediterranean buffalo, the Authors examined 164 fetuses from 80 different buffalo herds in Southern Italy. Three fetuses, came from two different herds, were positive. Our study confirms the pathogenic role of C. pecorum in buffalo, not only as a cause of neuropathology in calves but as an infectious abortive agent
Stimulated single-fiber electromyography (sSFEMG) in Lambert-Eaton syndrome
Objective: To report the clinical features and the neurophysiological approach of a patient with Lambert-Eaton myasthenic syndrome (LEMS), highlighting the diagnostic role of the stimulated single fiber electromyography (sSFEMG). Case report: A 60-year-old woman presenting with the LEMS triad (proximal and axial weakness, autonomic dysfunction and areflexia) was evaluated by neurophysiological tests (electroneuromyography, repetitive stimulation test (TSR), voluntary and stimulated SFEMG). We reported: 1) increase of compound muscle action potential (CMAP) amplitude (>60%) following brief isometric exercise compared to the rest (baseline); 2) decremental/incremental response of CMAP amplitude at low- (3 Hz) and high-frequency (30 Hz) repetitive stimulation test (RST), respectively; 3) increased neuromuscular jitter and blocking at voluntary single-fiber electromyography (vSFEMG); 4) stimulation rate-dependent reduction of the neuromuscular jitter and blocking at sSFEMG. Diagnosis was confirmed by serological demonstration of circulating voltage gated calcium channels (VGCC) antibodies. Significance: The present case highlights the role of the sSFEMG in the diagnosis of LEMS, underling the stimulation rate-dependency of both neuromuscular jitter and blocks
Extraction of phenolic compounds from 'Aglianico' and 'Uva di Troia' grape skins and seeds in model solutions: Influence of ethanol and maceration time
The effect of increasing concentration of ethanol (0, 4, 7.5 and 13 %) and contact time (respectively 1, 4, 7 and 10 days) on the extraction of phenolics from berry skins and seeds of the grape, Vitis vinifera 'Aglianico' and 'Uva di Troia', were examined. Two assays of post-fermentative maceration in two hydroalcoholic solutions at 11 and 13 % ethanol, were also performed. Chromatic properties and phenolics of medium were analyzed by HPLC and spectrophotometric methods. The extraction of total phenolics, anthocyanins, proanthocyanidins, and vanilline reactive flavans (VRF) from berry skins reached the maximum on the 4th day of maceration. Quercetin and gallic acid were gradually extracted from grape skins. The maximum release of flavan-3-ols from the skins was achieved on the first day of maceration. Total phenolics, tannins and VRF were gradually extracted from seeds. During the postfermentative maceration, higher the content of ethanol, higher the extraction of total polyphenols and tannins from 'Uva di Troia' skins and the extraction of total polyphenols and tannins from 'Aglianico' seeds. These results clearly indicate that the grape cultivar mainly influences the release of phenolic compounds from the solid parts of berry to the must especially during postfermentative maceration.
MICROPILES TRIPODS SHIELDS (MTS) AS UNCONVENTIONAL BREAKERS FOR THE CONTROL OF MODERATELY RAPID EARTHFLOWS (SASSI NERI LANDSLIDE, NORTHERN APENNINES)
The paper deals with the idea, design and implementation of unconventional one-of-a-kind Micropiles Tripods Shields (MTS) intended to break and decelerate moderately rapid earthflows surges in the track zone of the Sassi Neri landslide (Nure Valley, Northern Apennines, Province of Piacenza, Italy). The MTS are inspired to floating anchors and “chevaux de fries” used in wartime. The basic elements are tripods of 193 mm diameter steel micropiles laid out at triangle, driven into the stable bedrock and emerging some meters aboveground. Each tripod consists of a vertical upslope central pile and two lateral oblique piles, linked by two transversal beams and connection plates aboveground. Multiple tripods are spaced along transversal rows to form Micropiles Tripods Shields (MTS) to advancing earthflows. The design of MTS has been based on field investigations such as boreholes and geophysics, that indicated a limited thickness of landslide deposits in the track zone where MTS have been installed. The forces resulting from active earthflows fronts have been estimated both with geotechnical and hydraulic computations. The analysis of vertical and transversal forces as well as bending moments acting on a single tripod versus the characteristic resistances was carried out using a bi-dimensional scheme with finite-elements software Plaxis, that indicated that the stress levels were compatible with the structural resistance of the tripods. The construction of MTS took place in 2018, involving working site preparation with partial lime-treatment of the surficial layers, underground micropiles drilling and installation, aboveground micropiles welding, tripods completion with connection beams and plates. Some tripods have been instrumented with load cells for monitoring earth pressures against micropiles, electric transducers for groundwater monitoring next to the piles, tiltmeters for tripods rotations and a total station for slope and tripods movements monitoring. Results show that the acceleration of slope movements corresponds to a generalized increase of pore water pressure at all the monitored tripods and to temporary slight tilting of the tripods which has so far being fully recovered when the landside slowed down and pressure decreased. This pioneering application indicates that once the characteristics of the earthflows are carefully considered, the depth to the bedrock in the installation zone is limited, and the logistical conditions in the field during construction are adequate, the MTS can be taken into consideration as a possible unconventional solution to break down and control moderately rapid earthflow
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