431 research outputs found

    Ruptured middle cerebral artery aneurysms. retrospective study and multivariate analysis of 105 patients treated by surgical clipping

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    Objective of the study: We analyze in this study only patients with surgically treated ruptured aneurysms in order to identify statistical significance of each predictive factor in terms of outcome of patients with ruptured MCAAs. Materials and methods: In this retrospective study, we analyzed 105 cases of ruptured MCAAs, admitted from January 2001 to December 2015 at Neurosurgical Department of Umberto I University Hospital of Rome, Italy. Predictive factors evaluated are: Patient’s features (age, sex, co-morbidities), aneurysmal location (proximal, bifurcation or distal) and size of aneurysmal dome (small, large or giant); surgical timing (ultra-early, early, delayed), and Intracerebral Hemorrhage (ICH) volume. For each parameter we calculated mean and standard deviation, covariance and relation coefficient (through the linear regression model). Results: The clinical evaluation of patients assessed through the World Federation of Neurological Surgeons (WFSN) grading scale, that is 5 for 37 patients (35.3%), 4 for 28 patients. In 40% of cases the maximum sac diameter was between 7 mm and 12 mm, while in 67% of the cases the aneurysms concerned the bifurcation of the middle cerebral artery. ICH was associated in 57 cases (54.3%). As far as outcome is concerned, at 3 months, 32 patients (30.47%) had a favourable outcome, while 73 (69.52%) patients had not favourable outcome. To one year, 46 patients (43.8%) had favourable outcomes, while 59 patients (56.19%) had not favourable outcome. The mean outcomes as mean mRS are significantly less favourable in patients with ICH. Conclusion: In MCAAs patients, the presence of ICH strongly affects the outcome with a marked increase in mortality and morbidity. Surgical timing significantly influences the outcomes and ultra-early surgery should always be taken into account

    InGaAs/InP single-photon detector gated at 1.3 GHz with 1.5% afterpulsing

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    We demonstrate a single-photon detector based on InGaAs/InP single-photon avalanche diodes (SPADs) sinusoidalgated at 1.3 GHz with very low afterpulsing (about 1.5%), high dynamic range (maximum count rate is 650 Mcount/s), high photon detection efficiency (>30% at 1550 nm), low noise (per-gate dark count rate is 2.2 x 10(-5)), and low timing jitter (<70 ps full-width at half-maximum). The SPAD is paired with a "dummy" structure that is biased in antiphase. The sinusoidal gating signals are cancelled by means of a common-cathode configuration and by adjusting the relative amplitude and phase of the signals biasing the two arms. This configuration allows us to adjust the gating frequency from 1 to 1.4 GHz and can be operated also in the so-called gate-free mode, with the gate sine-wave unlocked with respect to the light stimulus, resulting in a free-running equivalent operation of the InGaAs/InP SPAD with about 4% average photon detection efficiency at 1550 nm

    InGaAs/InP SPAD with Monolithically Integrated Zinc-Diffused Resistor

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    Afterpulsing and optical crosstalk are significant performance limitations for applications employing near-infrared single-photon avalanche diodes (SPADs). In this paper, we describe an InGaAs/InP SPAD with monolithically integrated resistor that is fully compatible with the planar fabrication process and provides a significant reduction of the avalanche charge and, thus, of afterpulsing and optical crosstalk. In order to have a fast SPAD reset (<50 ns), we fabricated quenching resistors ranging from 10 to 200 k\Ω, smaller than what is available in the literature. The resistor, fabricated with the zinc diffusions already used for avoiding premature edge-breakdown, promptly reduces the avalanche current to a low value ∼ 100~ μ A in less than 1 ns, while an active circuit completes the quenching and enforces a well-defined hold-off. The proposed mixed-quenching approach guarantees an avalanche charge reduction of more than 20 times compared with similar plain SPADs, enough to reduce the hold-off time down to 1 μ s. Finally, a compact single-photon counting module based on this detector and featuring 70-ps photon-timing jitter is presented

    Integrated Circuit for Subnanosecond Gating of InGaAs/InP SPAD

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    We present a novel integrated circuit for subnanosecond gating of InGaAs/InP single-photon avalanche diodes (SPADs). It enables the detector in well-defined time intervals (down to 500 ps) and strongly reduces the afterpulsing effect. It includes a fast pulser with rising/falling edge shorter than 300 ps (20%-80%), a wideband comparator and hold-off logic circuitry. The fast avalanche quenching reduces the charge flow in the SPAD, thus decreasing the afterpulsing, a detrimental effect that limits the maximum count rate of InGaAs/InP SPADs. The wideband SiGe comparator guarantees very low timing jitter of the acquired waveforms: <100 ps (FWHM) at 5 V excess bias voltage, when operated with InGaAs/InP SPAD, whereas we estimate that the time jitter of the circuit is < 30 ps

    Anatomical theatre place of Knowledge – the pivotal role of anatomist in its realization

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    Human anatomy dissection represented a cornerstone in the evolution of medicine and modern scientific thought. The anatomical theatres, some of which are considered true masterpieces of architecture, are the place where concretely men learned to know themselves with a scientific method. Anatomists had a pivotal role in the buildings of anatomical theatres, using their knowledge in the research process of more functional architectures for demonstrative and experimental science. Antonio Scarpa (1752-1832) is an emblematic figure in this scenario. He studied anatomy at the University of Padua in the oldest permanent anatomical theatre of the world, originate in 1594 from a joint project conceived by Paolo Sarpi, scientist and church reformer, and Hieronymus Fabricius Ab Aquapendente, anatomist. In 1772, Scarpa became professor at the University of Modena. Bearing witness to the architectural value of the theatre in Padua is the fact that in 1774 Scarpa, involved in the planning for an anatomical theatre in Modena, had the professor of surgery in Padua, Girolamo Vandelli, send him a wooden model of the theatre there. Another project, less expensive, was selected instead. Later, in 1783, Scarpa was made professor of anatomy at the University of Pavia and promptly he promoted the building of an anatomical theatre there. The building was concluded in 1785, its semicircular layout is modeled on ancient theatres and the Palladian Olympic Theatre of Vicenza. Today, most of the anatomical theatres are lost or forgotten. The Thesa project will provide a census of anatomical theatres, both survived and not, which will allow us to identify connections among them, among the anatomists who studied there and the mutual influences that characterize their form. We believe the achievement of these objectives defines the essential conditions necessary to regain full awareness of the value of anatomical theatres in both the academic and popular contexts, thus creating a fertile cultural basis for new initiatives that can continue the quest for knowledge undertaken in the past in these places. From an architectural and evocative perspective, they are and will remain places where man puts himself at the centre and at the same time observes himself

    Fractures and dislocations of the lisfranc tarso-metatarsal articulation: outcome related to timing and choice of treatment

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    A Lisfranc injury is when one or more of the metatarsals are displaced from the tarsus. The term is more commonly used to describe an injury to the midfoot, centred on the 2nd tarso-metatarsal joint. These fractures are sometimes easily overlooked, especially if they are part of a polytrauma. They are often difficult to diagnose and treat, but if they go undetected and are not properly treated, they can cause long-term or chronic disability. Our team reviewed a group of 71 patients with a Lisfranc fracture dislocation. The lesions were classified according to Meyerson classification. All the patients were re-evaluated 3 years after their surgeries by clinical examination, Ankle-Hindfoot Scale AOFAS questionnaire, X-rays and baropodometric analysis. This review outlines the treatment outcome of this injury, taking into consideration the timing of diagnosis

    Design and verification of a micro wells turbine for Mediterranean operations

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    In the framework of the Poseidone Project we have designed a Wells turbine for Mediterranean operations. Here we present RANS computations carried out with OpenFOAM at different operating conditions. Rotor-stator interaction was synthetized with MRF approach and RANS closure relied on the cubic eddy viscosity closure of Lien et al. The virtual test rig reproduced the ISO conditions of the laboratory and was able to correctly predict torque and efficiency at different operations. Computations moreover allowed to acquire information on the threedimensional velocity and pressure field that develops inside the Wells turbine. The aim was to have an insight on the secondary motions and on the possible stall mechanism that characterize the device at low flow rates. Results were successfully validated against experimental measures

    The demonstration of the Sense Organs in the waxes of the Bologna school between XVIII and XIX century

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    In the field of the morphological disciplines the name of Filippo Pacini (1812-1883) is mostly related to the discovery of the sensitive Pacinian Corpuscles of the skin, but also to studies about the eye, particularly in the microscopical structure of the retina. Because this important respect of his scientific work, it seems appropriate to investigate the contribution of anatomical wax modelling to the representation of the sense organs between XVIII end XIX century. Considering the school of Ercole Lelli (1702-1766) in Bologna, of particular interest are the models made by Anna Morandi Manzolini (1716-1775). The approach in demonstrating the sense of tact is exquisitely functional, not only anatomical, by a wax reproducing two hands, one of them in the action of touching, the other withdrawing from a wounding object, thus giving a lively scene of a function, the tact, that at time science could not yet explain in their inner mechanisms. In the set of waxes about the vision, besides the general conformation of the eye and of the extrinsic muscles, is well presented the structure of the eyeball with the three tunics and vessels. Quite different in the artistic feature are the models of the eye and lachrymal apparatus performed by Cesare Bettini (1814-1885) about a century later. These waxes are of great dimensions, to be more useful for their educational purposes. The waxes of the school of Bologna not show the microscopic appearance of the organs: it was still too early for this kind of knowledge at the time of Anna Morandi Manzolini, but also the preparations of the wax modelers of the XIX century, at the epoch of the anatomists Francesco Mondini (1786-1844) and Luigi Calori (1807-1896), are not devoted to these fine aspects, that instead we can find in other collections, as those of the Anatomy Museum of the University of Florence
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