100 research outputs found

    The Hateful Eight: Connecting Massive Substructures in Galaxy Clusters like A2744 to Their Dynamical Assembly State Using the Magneticum Simulations

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    Substructures are known to be good tracers for the dynamical states and recent accretion histories of the most massive collapsed structures in the universe, galaxy clusters. Observations find extremely massive substructures in some clusters, especially Abell 2744 (A2744), which are potentially in tension with the ΛCDM paradigm because they are not found in simulations directly. However, the methods to measure substructure masses strongly differ between observations and simulations. Using the fully hydrodynamical cosmological simulation suite Magneticum Pathfinder, we develop a method to measure substructure masses in projection from simulations, similarly to the observational approach. We identify a simulated A2744 counterpart that not only has eight substructures of similar mass fractions but also exhibits similar features in the hot gas component. This cluster formed only recently through a major merger together with at least six massive minor merger events since z = 1, where previously the most massive component had a mass of less than 1 × 1014 M ⊙. We show that the mass fraction of all substructures and of the eighth substructure separately are excellent tracers for the dynamical state and assembly history for all galaxy cluster mass ranges, with high fractions indicating merger events within the last 2 Gyr. Finally, we demonstrate that the differences between subhalo masses measured directly from simulations as bound and those measured in projection are due to methodology, with the latter generally 2-3 times larger than the former. We provide a predictor function to estimate projected substructure masses from SubFind masses for future comparison studies between simulations and observations

    Numerical model of a valvuloplasty balloon: in vitro validation in a rapid‑prototyped phantom

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    Background Patient-specific simulations can provide insight into the mechanics of cardiovascular procedures. Amongst cardiovascular devices, non-compliant balloons are used in several minimally invasive procedures, such as balloon aortic valvuloplasty. Although these balloons are often included in the computer simulations of these procedures, validation of the balloon behaviour is often lacking. We therefore aim to create and validate a computational model of a valvuloplasty balloon. Methods A finite element (FE) model of a valvuloplasty balloon (Edwards 9350BC23) was designed, including balloon geometry and material properties from tensile testing. Young’s Modulus and distensibility of different rapid prototyping (RP) rubber-like materials were evaluated to identify the most suitable compound to reproduce the mechanical properties of calcified arteries in which such balloons are likely to be employed clinically. A cylindrical, simplified implantation site was 3D printed using the selected material and the balloon was inflated inside it. The FE model of balloon inflation alone and its interaction with the cylinder were validated by comparison with experimental Pressure–Volume (P–V) and diameter–Volume (d–V) curves. Results Root mean square errors (RMSE) of pressure and diameter were RMSE P = 161.98 mmHg (3.8 % of the maximum pressure) and RMSE d = 0.12 mm (<0.5 mm, within the acquisition system resolution) for the balloon alone, and RMSE P = 94.87 mmHg (1.9 % of the maximum pressure) and RMSE d = 0.49 mm for the balloon inflated inside the simplified implantation site, respectively. Conclusions This validated computational model could be used to virtually simulate more realistic valvuloplasty interventions

    Exercise Prescription in Patients With Arrhythmias

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    Epidemiological, clinical and laboratory studies have yielded definitive evidence that physical activity is able to reduce the morbidity and mortality of cardiovascular diseases and to improve physical fitness and quality of life. Moreover, physical activity seems to be capable of significantly reducing the risk of developing other chronic diseases, such as obesity, osteoporosis, diabetes, some neoplasms and depression. For these reasons, physical exercise has been proposed as an efficacious, low-cost, physiological means of disease prevention and therapy. However, although enormous amounts of scientific data have demonstrated the benefits of a physically active lifestyle, only a minority of people in Europe take regular physical exercise. One of the prime objectives of healthcare institutions is therefore to promote physical activity in the general population, as well as in patients with cardiovascular diseases.In the present review, we analyze the following points: some clinical aspects of arrhythmias and their relationships with physical exercise; the specific recommendations for exercise prescription in the various arrhythmias and in arhythmogenic heart diseases; the interactions between physical activity and antiarrhythmic therapies

    The role of Dietitian in cardiac rehabilitation and secondary prevention

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    Rehabilitation and secondary prevention programs are recognized as an essential part of the overall care of patients with cardiovascular disease. They consist of multidisciplinary strategies aiming at the reduction of modifiable risk factors for cardiovascular disease. There are some evidence of the efficacy of nutritional care in modifying eating habits and behavior in patients undergoing cardiac rehabilitation. In 2007, the Italian Association of Dietitians (ANDID) appointed a working group of dietitians, skilled in nutrition applied in cardiovascular disease, with the aim to make an overview of the available scientific literature and to develop a Professional Position Paper on the role of Dietitian in cardiac rehabilitation and secondary prevention. The first Position Paper, developed in 2008, covered the available evidence about the dietitian professional role and contribution in the management of the topic. The working group has recently updated the contents by introducing, in agreement with the work done by ANDID, the methodology of the Nutrition Care Process and Model (NCP), a systematic problem-solving method intended to stimulate critical thinking, decision-making and address issues related to food and nutritional assistance, in order to provide a safe, effective and high quality care

    [Mediterranean diet: not only food].

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    The proposal of a Mediterranean way of life is much more than advise how to eat. The Mediterranean Diet, a model of Sustainable Diet, is an example of how to combine personal choices, economic, social and cultural rights, protective of human health and the ecosystem. There is in fact fundamental interdependence between dietary requirements, nutritional recommendations, production and consumption of food. In literature studies and nutritional and epidemiological monitoring activities at national and international level have found a lack of adherence to this lifestyle, due to the spread of the economy, lifestyles of the Western type and globalization of the production and consumption. To encourage the spread of a culture and a constant practice of the Mediterranean Diet, there are some tools that are presented in this article. The Mediterranean Diet Pyramid in addition to the recommendations on the frequency and portions of food, focuses on the choice of how to cook and eat food. The "Double Food Pyramid" encourages conscious food choices based on "healthy eating and sustainability. All the nutrition professionals and dietitians in particular should be constantly striving to encourage the adoption of a sustainable and balanced nutrition

    Numerical model of a valvuloplasty balloon:in vitro validation in a rapid-prototyped phantom

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    BACKGROUND: Patient-specific simulations can provide insight into the mechanics of cardiovascular procedures. Amongst cardiovascular devices, non-compliant balloons are used in several minimally invasive procedures, such as balloon aortic valvuloplasty. Although these balloons are often included in the computer simulations of these procedures, validation of the balloon behaviour is often lacking. We therefore aim to create and validate a computational model of a valvuloplasty balloon. METHODS: A finite element (FE) model of a valvuloplasty balloon (Edwards 9350BC23) was designed, including balloon geometry and material properties from tensile testing. Young’s Modulus and distensibility of different rapid prototyping (RP) rubber-like materials were evaluated to identify the most suitable compound to reproduce the mechanical properties of calcified arteries in which such balloons are likely to be employed clinically. A cylindrical, simplified implantation site was 3D printed using the selected material and the balloon was inflated inside it. The FE model of balloon inflation alone and its interaction with the cylinder were validated by comparison with experimental Pressure–Volume (P–V) and diameter–Volume (d–V) curves. RESULTS: Root mean square errors (RMSE) of pressure and diameter were RMSE(P) = 161.98 mmHg (3.8 % of the maximum pressure) and RMSE(d) = 0.12 mm (<0.5 mm, within the acquisition system resolution) for the balloon alone, and RMSE(P) = 94.87 mmHg (1.9 % of the maximum pressure) and RMSE(d) = 0.49 mm for the balloon inflated inside the simplified implantation site, respectively. CONCLUSIONS: This validated computational model could be used to virtually simulate more realistic valvuloplasty interventions

    Exercise Prescription in Patients With Arrhythmias

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    In the present review we analyze some clinical aspects of arrhythmias and their relationships with physical exercise; specific recommendations for exercise prescription in various arrhythmias and in arhythmogenic heart diseases, as well as the interactions between physical activity and antiarrhythmic therapies

    In Vitro Assessment of the Neuro-Compatibility of Fe-20Mn as a Potential Bioresorbable Material for Craniofacial Surgery

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    Background and Objectives:Spring-assisted surgery is a popular option for the treatment of non-syndromic craniosynostosis. The main drawback of this procedure is the need for a second surgery for spring removal, which could be avoided if a distractor material could be metabolised over time. Iron–Manganese alloys (FeMn) have a good trade-off between degradation rate and strength; however, their biocompatibility is still debated. Materials and Methods: In this study, the neuro-compatibility of Fe-20Mn (wt.%) was assessed using standard assays. PC-12 cells were exposed to Fe-20Mn (wt.%) and stainless steel via indirect contact. To examine the cytotoxicity, a Cell Tox Green assay was carried out after 1, 2, and 3 days of incubation. Following differentiation, a neurite morphological examination after 1 and 7 days of incubation time was carried out. The degradation response in modified Hank’s solution at 1, 3, and 7 days was investigated, too. Results: The cytotoxicity assay showed a higher toxicity of Fe-20Mn than stainless steel at earlier time points; however, at the latest time point, no differences were found. Neurite morphology was similar for cells exposed to Fe-20Mn and stainless steel.Conclusions: In conclusion, the Fe-20Mn alloy shows promising neuro-compatibility. Future studies will focus on in vivo studies to confirm the cellular response to Fe-20Mn.</p

    In Vitro Assessment of the Neuro-Compatibility of Fe-20Mn as a Potential Bioresorbable Material for Craniofacial Surgery

    Get PDF
    Background and Objectives: Spring-assisted surgery is a popular option for the treatment of non-syndromic craniosynostosis. The main drawback of this procedure is the need for a second surgery for spring removal, which could be avoided if a distractor material could be metabolised over time. Iron–Manganese alloys (FeMn) have a good trade-off between degradation rate and strength; however, their biocompatibility is still debated. Materials and Methods: In this study, the neuro-compatibility of Fe-20Mn (wt.%) was assessed using standard assays. PC-12 cells were exposed to Fe-20Mn (wt.%) and stainless steel via indirect contact. To examine the cytotoxicity, a Cell Tox Green assay was carried out after 1, 2, and 3 days of incubation. Following differentiation, a neurite morphological examination after 1 and 7 days of incubation time was carried out. The degradation response in modified Hank’s solution at 1, 3, and 7 days was investigated, too. Results: The cytotoxicity assay showed a higher toxicity of Fe-20Mn than stainless steel at earlier time points; however, at the latest time point, no differences were found. Neurite morphology was similar for cells exposed to Fe-20Mn and stainless steel. Conclusions: In conclusion, the Fe-20Mn alloy shows promising neuro-compatibility. Future studies will focus on in vivo studies to confirm the cellular response to Fe-20Mn
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