A stochastic delay differential model of cerebral autoregulation

Mathematical models of the cardiovascular system and of cerebral autoregulation (CAR) have been employed for several years in order to describe the time course of pressures and flows changes subsequent to postural changes. The assessment of the degree of efficiency of cerebral auto regulation has indeed importance in the prognosis of such conditions as cerebro-vascular accidents or Alzheimer. In the quest for a simple but realistic mathematical description of cardiovascular control, which may be fitted onto non-invasive experimental observations after postural changes, the present work proposes a first version of an empirical Stochastic Delay Differential Equations (SDDEs) model. The model consists of a total of four SDDEs and two ancillary algebraic equations, incorporates four distinct delayed controls from the brain onto different components of the circulation, and is able to accurately capture the time course of mean arterial pressure and cerebral blood flow velocity signals, reproducing observed auto-correlated error around the expected drift

Classification of ductile cast iron specimens based on image analysis and support vector machine

The ductile irons discovery in 1948 gave a new lease on life to the cast iron family. In fact, these cast irons are characterized both by a high castability and by high toughness values, combining cast irons and steel good properties. The high mechanical properties (especially ductility) are mainly due to the peculiar graphite elements shape: thanks to the addition of some elements like Mg, Ca, Ce, graphite elements shape can be near to spheres (nodules) instead to lamellae as in "normal" grey cast irons. In this work, the problem of classification of ductile cast irons specimens is addressed; first the nodules present in each specimen are identified determining their morphological shapes. These characteristics are suitable used to extract global features of the specimen. Then it is outlined a procedure to train a classifier based of these properties

On the possible tools for the prevention of non-performing loans. A case study of an Italian bank

This work analyses the contribution of an Information Systems (IS) to the implementation of credit monitoring as a new integrated process to prevent non-performing loans in a small bank. The study focuses on the process of active monitoring of the entire credit portfolio, aimed at guiding the best migration between risk classes. This is understood as a set of integrated activities, in which the quality of information becomes a major determinant of the outcome. Such tools support risk management in the decision-making process and aiding performance evaluation. The purpose of this work is to highlight the possibility of an IS to support this new integrated process of credit monitoring, providing increasingly reliable data, availability on demand and real-time information

Recent advances in pharmacological treatment of heart failure

Background: Over the last years, several trials offered new evidence on heart failure (HF) treatment. Design and results: For HF with reduced left ventricular ejection fraction, type 2 sodium—glucose cotransporter inhibitors, aside from sacubitril—valsartan, demonstrated extraordinary efficacy in ameliorating patients' prognosis. Some new molecules (eg vericiguat, omecamtiv mecarbil and ferric carboxymaltose) correct iron deficiency and have shown to be capable of furthering reducing the burden of HF hospitalisation. Finally, there is new evidence on the possible therapeutic approaches of HF patients with mid-range or preserved left ventricular ejection fraction. Conclusions: This review aimed to revise the main novelties in the field of HF therapy and focus on how the daily clinical approach to patient treatment is changing

Spain and the crisis: housing prices, credit, and macroprudential policies

In this paper, we propose a two-country, two sector monetary union DSGE model with housing. One of the countries is calibrated to represent the Spanish economy while the other one is the rest of the European monetary union. First, we illustrate how looser credit conditions coming from the Euro area, together with increases in housing demand, lead to an increase in house prices and credit in Spain. Then, we analyze to what extent, macroprudential policies could have avoided the excess in credit that triggered the financial crisis in Spain. We find that a countercyclical loan-to-value rule that mainly responds to house prices would have mitigated the credit boom in Spain. These results can also be applied to other countries facing similar problems in the housing sector and thinking about implementing macroprudential policies

ACTIVE CONTOUR SEGMENTATION FOR THE IDENTIFICATION OF METALLOGRAPHIC AND MORPHOLOGICAL ELEMENTS OF INTEREST IN DUCTILE CAST IRON

Ductile cast irons are characterized by a wide range of mechanical properties that depend on graphite elements morphology and microstructure properties. Both chemical composition and manufacturing conditions control matrix microstructure, and ferritic, pearlitic, ferritic-pearlitic, martensitic, bainitic, austenitic and austempered ductile irons can be obtained. Considering crack propagation resistance of ductile cast irons, their peculiar behaviour is due to the graphite elements shape, that is approximately spheroidal. Due to their morphology, graphite elements can act as crack arresters: as a consequence ductile cast irons are characterized by high ductility and toughness values and can be used for loading conditions that could be considered as critical for other cast irons types (e.g. fatigue loading conditions). Up to some years ago, microstructure analysis was mainly performed by means of semi-quantitative procedures applied to metallographically prepared specimens, with the characteristics evaluation that was mainly based on the operator expertise. Only recently there has been an increasing interest in numerical procedures of image analysis for quantitative evaluation of materials. In this work the problem of the estimation of the morphological parameters of elements such as graphite nodules, domains of chemical etching and metallic matrix has been taken up by a variational approach of image segmentation by active contours. Considering ductile irons, images obtained by means of a light optical microscope (LOM) on metallographically prepared specimens show both graphite elements (spheroids, nodules, lamaellas etc.) and microstructure elements (ferrite grains, pearlite lamaellas, etc.) and some artefacts due the preparing procedure that should be distinguished by more interesting elements. An automatic identification procedure is here proposed to distinguish the nodules from the metallic matrix and to evaluate the nodules shape parameters of interest and the composition of the metallic matrix (ferrite/pearlite volume fraction)

ACTIVE CONTOUR SEGMENTATION FOR THE IDENTIFICATION OF METALLOGRAPHIC AND MORPHOLOGICAL ELEMENTS OF INTEREST IN DUCTILE CAST IRON

Ductile cast irons are characterized by a wide range of mechanical properties that depend on graphite elements morphology and microstructure properties. Both chemical composition and manufacturing conditions control matrix microstructure, and ferritic, pearlitic, ferritic-pearlitic, martensitic, bainitic, austenitic and austempered ductile irons can be obtained. Considering crack propagation resistance of ductile cast irons, their peculiar behaviour is due to the graphite elements shape, that is approximately spheroidal. Due to their morphology, graphite elements can act as crack arresters: as a consequence ductile cast irons are characterized by high ductility and toughness values and can be used for loading conditions that could be considered as critical for other cast irons types (e.g. fatigue loading conditions). Up to some years ago, microstructure analysis was mainly performed by means of semi-quantitative procedures applied to metallographically prepared specimens, with the characteristics evaluation that was mainly based on the operator expertise. Only recently there has been an increasing interest in numerical procedures of image analysis for quantitative evaluation of materials. In this work the problem of the estimation of the morphological parameters of elements such as graphite nodules, domains of chemical etching and metallic matrix has been taken up by a variational approach of image segmentation by active contours. Considering ductile irons, images obtained by means of a light optical microscope (LOM) on metallographically prepared specimens show both graphite elements (spheroids, nodules, lamaellas etc.) and microstructure elements (ferrite grains, pearlite lamaellas, etc.) and some artefacts due the preparing procedure that should be distinguished by more interesting elements. An automatic identification procedure is here proposed to distinguish the nodules from the metallic matrix and to evaluate the nodules shape parameters of interest and the composition of the metallic matrix (ferrite/pearlite volume fraction)

High-sensitivity C-reactive protein is a predictive factor of adiposity in children : results of the Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and InfantS (IDEFICS) study

Background-Whereas cross-sectional studies have shown that obesity is associated with increased C-reactive protein (CRP) levels in children, little is known about the impact of low-grade inflammation on body mass changes during growth. Methods and Results-We assessed cross-sectionally and longitudinally the association of high-sensitivity (hs)-CRP levels with overweight/obesity and related cardiometabolic risk factors in the Identification and prevention of Dietary-and lifestyle-induced health Effects in Children and InfantS (IDEFICS) cohort. 16 224 children from 8 European countries (2 to 9 years) were recruited during the baseline survey (T0). After the exclusion of 7187 children because of missing hs-CRP measurements and 2421 because of drug use during the previous week, the analysis was performed on 6616 children (Boys=3347; Girls=3269; age=6.3 +/- 1.7 years). Of them, 4110 were reexamined 2 years later (T1). Anthropometric variables, blood pressure, hs-CRP, blood lipids, glucose and insulin were measured. The population at T0 was divided into 3 categories, according to the baseline hs-CRP levels. Higher hs-CRP levels were associated with significantly higher prevalence of overweight/obesity, body mass index (BMI) z-score and central adiposity indices (P values all <0.0001), and with higher blood pressure and lower HDL-cholesterol levels. Over the 2-year follow-up, higher baseline hs-CRP levels were associated with a significant increase in BMI z-score (P<0.001) and significantly higher risk of incident overweight/obesity. Conclusions-Higher hs-CRP levels are associated to higher body mass and overweight/obesity risk in a large population of European children. Children with higher baseline levels of hs-CRP had a greater increase in BMI z-score and central adiposity over time and were at higher risk of developing overweight/obesity during growth

Fatigue crack propagation mechanisms in C70250 and CuCrZr copper alloys

A previous study concerning the characterization of CuNiSi (C70250) and CuCrZr alloys showed very interesting characteristics of toughness evaluated with tensile tests and preliminary tests on Charpy specimens. These alloys could have interesting applications such as devices used for energy production, particle physics and aerospace. These alloys are used in the ITER (International Thermonuclear Experimental Reactor) project, an international program of great interest. For this reason, it seems important to characterize the mechanical properties of these alloys. In particular, fatigue crack propagation rate (da/dn vs ΔK) measurements were performed

Evidence of structural cavities in 3D printed acetabular cups for total hip arthroplasty

The use of three‐dimensional (3D) printing to manufacture off‐the‐shelf titanium acetabular cups for hip arthroplasty has increased; however, the impact of this manufacturing technology is yet not fully understood. Although several studies have described the presence of structural cavities in 3D printed parts, there has been no analysis of full postproduction acetabular components. The aim of this study was to investigate the effect of 3D printing on the material structure of acetabular implants, first comparing different designs of 3D printed cups, second comparing 3D printed with conventionally manufactured cups. Two of the 3D printed cups were produced using electron beam melting (EBM), one using laser rapid manufacturing (LRM). The investigation was performed using X‐ray microcomputed tomography, imaging both the entire cups and samples sectioned from different regions of each cup. All 3D printed cups showed evidence of structural cavities; these were uniformly distributed in the volume of the samples and exhibited a prevalent spherical shape. The LRM‐manufactured cup had significantly higher cavity density (p = .0286), with a median of 21 cavities/mm^{3} compared to 3.5 cavities/mm^{3} for EBM cups. However, the cavity size was similar, with a median of 20 μm (p = .7385). The conventional cups showed a complete absence of distinguishable cavities. The presence of cavities is a known limitation of the 3D printing technology; however, it is noteworthy that we found them in orthopedic implants used in patients. Although this may impact their mechanical properties, to date, 3D printed cups have not been reported to encounter such failures