1,721,110 research outputs found
Monete
No full textIn Lessinia nel corso di una serie prolungata di ricerche di superficie sono stati rinvenuti molti reperti, testimonianza della vita e del lavoro dei pastori in un arco temporale molto lungo. Sono state recuperate anche più di 400 monete, prevalentemente di bronzo del XV secolo, alcune sono anche di età romana e provengono da pascoli a quota molto alta
Archeologia e montagna: i nodi critici rilevati dal progetto "Oltre il confine" (Recoaro Terme, VI)
No full textAbstract: In the first part of the paper, motivations, methods used and initial results obtained from the “Oltre il confine” Project held in Recoaro Terme (VI) in the years 2019-2021 are presented. In the second part of the paper, the excavation of three shelters is discussed, underlining their membership in larger systems. In the 15th-18th centuries they were subject of interest for the close mountain communities, but also for the aristocratic families residing further afield and for the policies of the Republic of Venice. During the Recent and Final Bronze age the shelters and, more widely, the findings in these high pastures, often prestigious ones, hint at pastures, travel routes, exchanges, boundaries and rituals. In the final part of the paper, some method consideration about the archaeological work in the high quotes are presented
Numerical investigation of the intravascular coronary stent flexibility
Full text linkNowadays stent therapy is widely adopted to treat atherosclerotic vessel diseases. The high commercial value of these devices and the high prototypation costs require the use of finite element analyses, instead of classical trial and error technique, to design and verify new models. In this paper, we explore the advantages of the finite element method (FEM) in order to investigate new generation stent performance in terms of flexibility. Indeed, the ability of the stent to bend in order to accommodate curvatures and angles of vessels during delivery is one of the most significant prerequisites for optimal stent performance. Two different FEM models, resembling two new generation intravascular stents, were developed. The main model dimensions were obtained by means of a stereo microscope, analyzing one Cordis BX-Velocity and one Carbostent Sirius coronary stent. Bending tests under displacement control in the unexpanded and expanded configuration were carried out. The curvature index, defined as the ratio between the sum of rotation angles at the extremes and the length of the stent, yielded comparative information about the capability of the device to be delivered into tortuous vessels and to conform to their contours. Results, expressed in terms of the bending moment-curvature index, demonstrated a different response for the two models. In particular the Cordis model showed a higher flexibility. Lower flexibility in the expanded configurations for both models was detected. However this flexibility depends on how the contact takes place between the different parts of the struts
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evaluation of segmentation accuracy and its impact on patient-specific CFD analysis
Full text linkMedical image segmentation, especially for biological soft tissues, is an issue of great interest. The aim of this study is to evaluate the segmentation performance of a commercial and an open-source software, to segment aortic root and coronary arteries. 3D printing stereolithography technology was used to generate ground truth models, which were then re-acquired by means of a micro-CT scanner. Measurements from the printed and reconstructed models with both the software were compared, in order to evaluate the level of agreement. In the second phase of this study, Computational Fluid Dynamics (CFD) simulations were conducted, to compare the outputs between the models segmented with the two software. The goal was to understand how differences in the segmentation process propagate in CFD results. Results showed that both software guarantee satisfactory segmentation performance, with average geometrical differences between reconstructed and physical models in the order of a few percentage points. However, when we consider thin details, as a sharp stenotic region, the commercial validated software seems to be more accurate in replicating the real anatomy. We also realized how apparently negligible geometrical differences, varying the employed software, can turn into enormous variations of hemodynamic parameters, such as velocity and wall shear stress, which place in the centre the delicate role the segmentation process holds. This evidence is crucial in the biomedical field and especially in a coronary arteries study, where CFD simulations can be exploited as a starting point for surgery considerations
In silico approaches for transcatheter aortic valve replacement inspection
No full textIntroduction: Increasing applications of transcatheter aortic valve replacement (TAVR) to treat high- or medium-risk patients with aortic diseases have been proposed in recent years. Despite its increasing use, many influential factors are still to be understood. Furthermore, innovative applications of TAVR such as in bicuspid aortic valves or in low-risk patients are emerging in clinical use. Numerical analyses are increasingly used to reproduce clinical treatments. The future trends in this area are foreseen for in silico trials and personalized medicine. Areas covered: This review paper analyzes the recent years (Jan 2018–Aug 2020) of in silico studies simulating the behavior of transcatheter aortic valves with emphasis on the addressed clinical question and the used modeling strategies. The manuscripts are firstly classified based on their clinical hypothesis. A second classification is based on the adopted modeling approach in terms of patient domain, device modeling, and inclusion or exclusion of the fluid domain. Expert opinion: The TAVR can be virtually performed in numerous vessel geometries and with different devices. This versatility allows a rapid evaluation of the feasibility of different implantation approaches for specific patients, and patient populations, resulting in faster and safer introduction or optimization of new treatments or devices
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