39 research outputs found

    Design and Prototyping of Miniaturized Straight Bevel Gears for Biomedical Applications

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    This paper presents a semi-automated design algorithm for computing straight bevel gear involute profiles. The proposed formulation is based on the Tredgold approximation method. It allows the design of a pair of bevel gears with any desired number of teeth and relative axes inclination angles by implementing additive manufacturing technology. A specific case study is discussed to calculate the profiles of two straight bevel gears of a biomedical application. Namely, this paper illustrates the design of the bevel gears for a new laparoscopic robotic system, EasyLap, under development with a grant from POR Calabria 2014–2020 Fesr-Fse. A meshing analysis is carried out to identify potential design errors. Moreover, finite element-based tooth contact analysis is fulfilled for determining the vibrational performances of the conjugate tooth profiles throughout a whole meshing cycle. Simulation results and a built prototype are reported to show the engineering feasibility and effectiveness of the proposed design approach

    ROSES, the only RObotic System for any Endovascular Surgery, Including the Control of an Animated Catheter Characterized by the Presence of two Controlled Curvatures

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    The paper presents ROSES, its robotic components, the different devices, not necessarily sterile, and its disposables, suitable for any endovascular procedure, both actually performed and presently not assisted by any robotic system, and open in the future for new application yet to come, such as what will be allowed by the new animated catheter. In fact, this is due to the mechanical configuration of the robotic actuators based on a peculiar gear train which presents a big passage hole which allows both the passage of big catheters and even hemostasis valves, as well as full control of very small catheters and guide wires. The system measures forces opposed by the body showing their value both numerically and analogically without the need of any. special tool, measures length of penetration of each catheter and guide wires recording their value. Thus, it may become in future, connected to a work station that will register in real time also the fluoroscopic images, a kind of black box of endovascular surgeries, separating completely doctor and nurses from the patient, using also cameras and microphones to replace the physical contact with the patient

    Prevalence of hypospadias in Italy according to severity, gestational age and birthweight: an epidemiological study

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    <p>Abstract</p> <p>Background</p> <p>Hypospadias is a congenital displacement of the urethral meatus in male newborns, being either an isolated defect at birth or a sign of sexual development disorders. The aim of this study was to assess the prevalence rate of hypospadias in different Districts of Italy, in order to make a comparison with other countries all over the world.</p> <p>Methods</p> <p>We reviewed all the newborns file records (years 2001–2004) in 15 Italian Hospitals.</p> <p>Results</p> <p>We found an overall hypospadias prevalence rate of 3.066 ± 0.99 per 1000 live births (82.48% mild hypospadias, 17.52% moderate-severe). In newborns Small for Gestational Age (birthweight < 10<sup>th </sup>percentile) of any gestational age the prevalence rate of hypospadias was 6.25 per 1000 live births. Performing multivariate logistic regression analysis for different degrees of hypospadias according to severity, being born SGA remained the only risk factor for moderate-severe hypospadias (p = 0.00898) but not for mild forms (p > 0.1).</p> <p>Conclusion</p> <p>In our sample the prevalence of hypospadias results as high as reported in previous European and American studies (3–4 per 1000 live births). Pathogenesis of isolated hypospadias is multifactorial (genetic, endocrine and environmental factors): however, the prevalence rate of hypospadias is higher in infants born small for gestational age than in newborns with normal birth weight.</p

    Triadin/Junctin Double Null Mouse Reveals a Differential Role for Triadin and Junctin in Anchoring CASQ to the jSR and Regulating Ca2+ Homeostasis

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    Triadin (Tdn) and Junctin (Jct) are structurally related transmembrane proteins thought to be key mediators of structural and functional interactions between calsequestrin (CASQ) and ryanodine receptor (RyRs) at the junctional sarcoplasmic reticulum (jSR). However, the specific contribution of each protein to the jSR architecture and to excitation-contraction (e-c) coupling has not been fully established. Here, using mouse models lacking either Tdn (Tdn-null), Jct (Jct-null) or both (Tdn/Jct-null), we identify Tdn as the main component of periodically located anchors connecting CASQ to the RyR-bearing jSR membrane. Both proteins proved to be important for the structural organization of jSR cisternae and retention of CASQ within them, but with different degrees of impact. Our results also suggest that the presence of CASQ is responsible for the wide lumen of the jSR cisternae. Using Ca2+ imaging and Ca2+ selective microelectrodes we found that changes in e-c coupling, SR Ca2+content and resting [Ca2+] in Jct, Tdn and Tdn/Jct-null muscles are directly correlated to the effect of each deletion on CASQ content and its organization within the jSR. These data suggest that in skeletal muscle the disruption of Tdn/CASQ link has a more profound effect on jSR architecture and myoplasmic Ca2+ regulation than Jct/CASQ association

    A performance model of a Wankel engine, including the effects of burning rates, heat transfer, leakage and quenching compared with measured pressure time histories

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    Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering.Microfiche copy available in Archives and Engineering.Vita.Bibliography: leaves 80-81.by Guido A. Danieli.Ph.D

    Progettazione end-effector per chirurgia laparoscopica

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    Scuola di Dottorato "Pitagora" in Scienze Ingegneristiche, Dottorato di Ricerca in Ingegneria Meccanica Ciclo XXIV, a.a. 2011-2012UniversitĂ  degli Studi della Calabri

    Image-Guided robotic system for precision biopsy

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    Dottorato di Ricerca in Ingegneria Meccanica XXVI Ciclo, a.a. 2013UniversitĂ  della Calabri

    Sviluppo, realizzazione e sperimentazione in vitro di un sistema ottico per il rilievo tridimensionale dell’arcata dentale

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    Scuola di Dottorato “Pitagora” in Scienze Ingegneristiche, Dottorato di Ricerca in Ingegneria Meccanica XXI Ciclo a.a. 2007-2008This thesis describes the development of a 3D scanning system based on an active vision technique that uses structured light to obtain the impression of the dental arch. Currently to realize a dental prosthesis a special doughy sticky material is adopted to impress the patient’s dental arch. This imprinting may be scanned and then analyzed and modified by C.A.D. software. All this process is sometimes too long, and it may take several weeks to obtain the final prosthesis. At that moment, there are only few works that use techniques to shorten the processing times and produce a three dimensional model of a dental arch, but often they don’t allow to obtain optimal results due to a low resolution and a slow acquisition rate. Among all the studies described on literature, it results that the structured light is a relatively simple technique that allows for a relative high resolution. In the last years, the development of all these systems, has draw the attention to those devices able to obtain a structure of patient’s dental arch as a C.A.D. model. The device developed and described in this thesis is a novel kind of optical scanner that allows for a total elaboration time, for the realization of a three dimensional model, which is lower than those of the systems described in literature. The new optical scanner consists of four digital camera, a multimedia DLP mini-projector and a software to manage the hardware and process the images. It is actuated by step motors on an 2D guide, which is held rigidly fixed to the denture of the patient by a self balanced kinematic chain, that allows for small motions of the patient’s head. This system designed allows the relief and automatic reconstruction through the use of structured light with a particular Gray-Code method. This work is mainly divided in two main parts: 1. The study of the optical system calibration 2. The study of the reconstruction of dental arch The technique used relies on a new version of Gray-Code method; which allows to solve the so called “correspondences problems”. The structured light is produced by a mini-projector, which has to undertake a calibration phase as well as the camera used for image acquisition. The second part of this study is related to the analysis and marge of the acquired images. This problem involves the alignement of the cloud of points obtained from the automatic scanning process by each camera. In this phase, all the errors involved in the whole procedure are also investigated.Università della Calabri
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