73 research outputs found

    A theoretical model of the endothelial cell morphology due to different waveforms

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    Endothelial cells are key units in the regulatory biological process of blood vessels. They represent an interface to transmit variations on the fluid dynamic changes. They are able to adapt its cytoskeleton, by means of microtubules reorientation and F-actin reorganization, due to new mechanical environments. Moreover, they are responsible for initiating a huge cascade of biological processes, such as the release of endothelins (ET-1), in charge of the constriction of the vessel and growth factors such as TGF-ß and PDGF. Although a huge efforts have been made in the experimental characterization and description of these two issues the computational modeling has not gained such an attention. In this work we study the 3D remodeling of endothelial cells based on the main features of blood flow. In particular we study how different oscillatory shear index and the time average wall shear stresses modify the endothelial cell shape. We found our model fitted the experimental works presented before in in vitro studies. We also include our model within a computational fluid dynamics simulation of a carotid artery to evaluate endothelial cell shape index which is a key predictor of atheroma plaque formation. Moreover, our approach can be coupled with models of collagen and smooth muscle cell growth, where remodeling and the associated release of chemical substance are involved.Peer ReviewedPostprint (author's final draft

    Influence of a commercial antithrombotic filter on the caval blood flow during neutra and valsalva maneuver

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    Anticoagulants are the treatment of choice for pulmonary embolism. When these fail or are contraindicated, vena cava filters are effective devices for preventing clots from the legs from migrating to the lung. Many uncertainties exist when a filter is inserted, especially during physiological activity such as normal breathing and the Valsalva maneuver. These activities are often connected with filter migration and vena cava damage due to the various related vein geometrical configurations. In this work, we analyzed the response of the vena cava during normal breathing and Valsalva maneuver, for a healthy vena cava and after insertion of a commercial Günther-Tulip® filter. Validated computational fluid dynamics (CFD) and patient specific data are used for analyzing blood flow inside the vena cava during these maneuvers. While during normal breathing, the vena cava flow can be considered almost stationary with a very low pressure gradient, during Valsalva the extravascular pressure compresses the vena cava resulting in a drastic reduction of the vein section, a global flow decrease through the cava but increasing the velocity magnitude. This change in the section is altered by the presence of the filter which forces the section of the vena cava before the renal veins to keep open. The effect of the presence of the filter is investigated during these maneuvers showing changes in wall shear stress and velocity patterns

    Regional-scale compositional and size fidelity of rocky interdidal comminities from the patagonian atlantic coast

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    Fil: Archuby, Fernando M.. Instituto de Investigación en Paleobiología y Geología. Universidad Nacional de Río Negro. General Roca; ArgentinaFil: Adami, Mariana Laura. División Zoología Invertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Martinelli, Julieta C.. Department of Biological Sciences. Macquarie University; AustraliaFil: Gordillo, Sandra. CICTERRA. Universidad Nacional de Córdoba; ArgentinaFil: Boretto, Gabriela M.. CICTERRA. Universidad Nacional de Córdoba; ArgentinaFil: Malve, Mariano E.. Facultad de Ciencias Exactas, Físicas y Naturales. Universidad Nacional de Córdoba; Argentin

    The Hemodynamics of Aneurysms Treated with Flow-Diverting Stents Considering both Stent and Aneurysm/Artery Geometries

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    Flow diverting stents are deployed to reduce the blood flow into the aneurysm, which would thereby induce thrombosis in the aneurysm sac; the stents prevent its rupture. The present study aimed to examine and quantify the impacts of different flow stents on idealized configurations of the cerebral artery. In our study, we considered a spherical sidewall aneurysm located on curved and tortuous idealized artery vessels and three stents with different porosities (70, 80 and 90%) for deployment. Using computational fluid dynamics, the local hemodynamics in the presence and absence of the stents were simulated, respectively, under the assumption that the blood flow was unsteady and non-Newtonian. The hemodynamic parameters, such as the intra-aneurysmal flow, velocity field and wall shear stress and its related indices, were examined and compared among the 12 cases simulated. The results illustrated that with the stent deployment, the intra-aneurysmal flow and the wall shear stress and its related indices were considerably modified depending on both stent and aneurysm/artery geometries, and that the intra-aneurysmal relative residence time increased rapidly with decreasing stent porosity in all the vessel configurations. These results also inform the rationale for selecting stents for treating aneurysms of different configurations

    Supracondylar fracture of femur: our experience of treatment with locking compression plate from rural Maharashtra

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    Background: Surgical treatment of supracondylar or intercondylar distal femoral fractures (AO/OTA types 33-A to 33-C) remains a significant surgical challenge with significant complication rates. Supracondylar and intercondylar fractures of femur are very often difficult to treat and they are notorious for many complications. We have studied use of LCP (locking compression plate) in the treatment of metaphyseal fractures. These implants improve fracture healing, especially in osteoporotic bone due to better holding capacity. Objective wass to assess the efficacy of LCP in maintenance of post-operative distal femoral alignment and in preventing post-operative varus collapse in supracondylar fracture of femur.Methods: Prospective Longitudinal observational study Conducted at Post Graduate Institute of Swasthiyog Pratishthan, Miraj, Maharashtra involving 50 patients with supracondylar fracture. The fractures were classified as supracondylar femur fracture (AO/OTA type 33) (A- C). Fractures that were supracondylar with significant proximal fracture extension were classified as an AO/OTA type 33 fracture unless there was a separate diaphyseal fracture. Data was analysed by using SPSS 16.0 version and expressed as percentages.Results: Majority of patients were from 30-39 years age group i.e. 32%. Majority of patients were males i.e. 46 (92%). 7 (14%) patients had healing time <4 months. 24 (48%) patients had healing time between 4-6 months. 19 (38%) patients had healing time more than 6 months. To assess the overall results, we used Knee society score. In 38% of patients, we found excellent results. Good and fair results were seen in 32% and 26% of patients.Conclusion: Locking compression plate is an ideal implant for fixation of supracondylar fracture of femur 33 (A-C) especially in C3 type where articular comminution is present

    Multidisciplinary investigation of two Egyptian child mummies curated at the University of Tartu Art Museum, Estonia (Late/Graeco-Roman Periods)

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    Two ancient Egyptian child mummies at the University of Tartu Art Museum (Estonia) were, according to museum records, brought to Estonia by the young Baltic-German scholar Otto Friedrich von Richter, who had travelled in Egypt during the early 19th century. Although some studies of the mummies were conducted, a thorough investigation has never been made. Thus, an interdisciplinary team of experts studied the remains using the most recent analytical methods in order to provide an exhaustive analysis of the remains. The bodies were submitted for osteological and archaeothanatological study, radiological investigation, AMS radiocarbon dating, chemical and textile analyses, 3D modelling, entomological as well as aDNA investigation. Here we synthesize the results of one of the most extensive multidisciplinary analyses of ancient Egyptian child mummies, adding significantly to our knowledge of such examples of ancient funerary practices.© 2020 Oras et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Impact of natural resource management interventions on water resources and environmental services in different agroecological regions of India

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    Natural resource management is critical for addressing issues of water scarcity, land degradation and poor agricultural and livestock productivity especially in rainfed ecologies. This study was conducted in 13 Gram panchayats (cluster of villages) of three states in India representing different agroecological regions. Natural resource management works undertaken through the Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA) covering water harvesting, pasture land and orchard development were evaluated between November 2015 and January 2016. Density of water harvesting varied from 10 to 250 m3 h

    Studies on rapid multiplication of black pepper (Piper nigrum L.) on soil mound

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    An experiment was conducted to study rapid multiplication of black pepper (Piper nigrum) on soil mound at Dapoli (Maharashtra). The black pepper plants were planted at the base of soil mound (2.5 m width, 0.60 m height at centre, 18 m length, 45' angle slope) at various spacings (15.0,22.5, 30.0 and 37.5 cm) and compared with cuttings raised by bamboo and traditional methods. The vines in soil mound method exhibited superior performance with respect to length and root production node". The availability of cuttings from soil mound method was also the highest. The rooting percentage of cuttings obtained from soil mound and bamboo methods were significantly superior over traditional method of propagation. The B : C ratio for marketable black pepper cuttings by soil mound method was the best (2.1:1.0). Planting base material at 15 cm spacing on soil mound was the best and produced more runners per unit area as compared to other spacing treatments and traditional method. &nbsp

    Ancient Bacterial Genomes Reveal a High Diversity of Treponema pallidum Strains in Early Modern Europe

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    Syphilis is a globally re-emerging disease, which has marked European history with a devastating epidemic at the end of the 15th century. Together with non-venereal treponemal diseases, like bejel and yaws, which are found today in subtropical and tropical regions, it currently poses a substantial health threat worldwide. The origins and spread of treponemal diseases remain unresolved, including syphilis' potential introduction into Europe from the Americas. Here, we present the first genetic data from archaeological human remains reflecting a high diversity of Treponema pallidumin early modern Europe. Our study demonstrates that a variety of strains related to both venereal syphilis and yaws-causing T. pallidum subspecies were already present in Northern Europe in the early modern period. We also discovered a previously unknown T. pallidum lineage recovered as a sister group to yaws- and bejel-causing lineages. These findings imply a more complex pattern of geographical distribution and etiology of early treponemal epidemics than previously understood

    Progress and Challenges in Coupled Hydrodynamic-Ecological Estuarine Modeling

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