Volcanic rocks were among the most sought-after materials to produce grinding tools in antiquity because lavas lithologies, either mafic or felsic, ensured good wear resistance and grinding capacity with respect to many other kinds of rocks. The interest in findings made of vesciculated lavas, referable to parts of querns, mortars, and/or pestles of the Final Bronze Age site of Monte Croce Guardia (Arcevia) lies in the fact that this settlement was built upon limestones belonging to the sedimentary sequence of the Marche-Umbria Apennines (central Italy) and far away from potential raw materials of volcanic rocks. A petrologic study of 23 grinding tool fragments clearly indicates a provenance from the volcanic provinces of central Italy: Latium and Tuscany Regions.
View Article and Find Full Text PDFA petrographic and geochemical study of several volcanic millstones, representative of 119 artifacts found in the ancient Greek colony of Megara Hyblaea (Sicily Island) and recording the grinding device evolution from the Archaic to the Hellenistic period, unravelled the volcanoes involved as quarrying and production areas. This was possible also through the comparison with available petrographic and geochemical literature data of ancient volcanic millstones found in the whole Mediterranean. Saddle querns, hopper-rubber, rotary Morgantina- and Delian-type millstones of Megara Hyblaea consist of lithotypes belonging to five magmatic series: Tholeiitic, Na-Alkaline, Tholeiitic Transitional, Calcalkaline and High-K Alkaline.
View Article and Find Full Text PDFA macroscopic lithological study and physical (hardness, size, weight) investigations, coupled with laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence (XRF) chemical analyses of three egg- and one pear-shaped polished black stones, exposed in the library of the child home of the famous poet Giacomo Leopardi, at Recanati (Italy), were carried out. They are characterized by different sizes: two with the same weight of 16.9 kg and the two smaller ones of 5.
View Article and Find Full Text PDFThe article deals with the investigation of geopolymer foams (GFs) synthesized using by-products coming from the (i) screening-, (iv) pyrolysis-, (iii) dust abatement- and (iv) fusion-processes of the secondary aluminum industry. Based on principles of the circular economy to produce new technological materials, the experimental study involves industrial by-products management through the recovery, chemical neutralization, and incorporation of these relatively hazardous waste into the GFs. The geopolymeric matrix, consisting of metakaolin (MK) and silica sand (SA) with a 1:1 wt.
View Article and Find Full Text PDFLarge-scale landslides at volcanic islands are one of the most dangerous geological phenomena, able to generate tsunamis whose effects can propagate far from the source. However, related deposits are scarcely preserved on-land in the geologic records, and are often difficult to be interpreted. Here we show the discovery of three unprecedented well-preserved tsunami deposits related to repeated flank collapses of the volcanic island of Stromboli (Southern Italy) occurred during the Late Middle Ages.
View Article and Find Full Text PDFBackground: The aim of this large retrospective study was to provide a logistic risk model along an additive score to predict early mortality after surgical treatment of patients with heart valve or prosthesis infective endocarditis (IE).
Methods: From 2000 to 2015, 2715 patients with native valve endocarditis (NVE) or prosthesis valve endocarditis (PVE) were operated on in 26 Italian Cardiac Surgery Centers. The relationship between early mortality and covariates was evaluated with logistic mixed effect models.
Objectives: We described clinical-epidemiological features of prosthetic valve endocarditis (PVE) and assessed the determinants of early surgical outcomes in multicentre design.
Methods: Data regarding 2823 patients undergoing surgery for endocarditis at 19 Italian Centers between 1979 and 2015 were collected in a database. Of them, 582 had PVE: in this group, the determinants of early mortality and complications were assessed, also taking into account the different chronological eras encompassed by the study.
Intraaortic balloon pump (IABP) is used as temporary mechanical assistance in case of cardiovascular diseases, even if different hemodynamic problems and, thus, clinical complications may happen, such as the decrease of visceral perfusion. A computational fluid dynamic (CFD) study was carried out to investigate the effects of different IABP-induced abdominal occlusions on patient-specific aortic flow. Two possible sizes (25 and 34 cm) and two locations (2 and 3 cm) of the balloon were compared, modeling four abdominal occlusions and numerically reproducing IAB inflation/deflation behavior.
View Article and Find Full Text PDFPurpose: The extracorporeal membrane oxygenation (ECMO) is a temporary, but prolonged circulatory support for cardiopulmonary failure. Clinical evidence suggests that pulsed flow is healthier than non pulsatile perfusion. The aim of this study was to computationally evaluate the effects of total and partial ECMO assistance and pulsed flow on hemodynamics in a patient-specific aorta model.
View Article and Find Full Text PDFObjective: To verify the rate of thromboembolic and hemorrhagic complications during the first 6 months after mitral valve repair and to assess whether the type of antithrombotic therapy influenced clinical outcome.
Methods: Retrospective data were retrieved from 19 centers. Inclusion criteria were isolated mitral valve repair with ring implantation.
Aims: To assess the results and impact of lesion set and surgical technique on long-term success of surgical ablation during mitral surgery.
Methods And Results: The patient population consisted of 685 subjects with persistent and long-standing persistent atrial fibrillation (AF) undergoing cardiac surgery for mitral valve disease as the primary indication and concomitant ablation between January 2003 and January 2012 at three institutions. One hundred and sixty-six underwent unipolar (24.
Background: We investigated the role of surgical ablation targeting the autonomous nervous system during a Cox-Maze IV procedure in the maintenance of sinus rhythm at long-term follow-up.
Methods: The patient population consisted of 519 subjects with persistent or long-standing persistent atrial fibrillation (AF) undergoing radiofrequency Maze IV during open heart surgery between January 2006 and July 2013 at three institutions without (Group 1) or with (Group 2) ganglionated plexi (GP) ablation. Recurrence of atrial fibrillation off-antiarrhythmic drugs was the primary outcome.
Aim: Consistent expansion of primary human endothelial cells in vitro is critical in the development of engineered tissue. A variety of complex culture media and techniques developed from different basal media have been reported with alternate success. Incongruous results are further confounded by donor-to-donor variability and cellular source of derivation.
View Article and Find Full Text PDFInt J Numer Method Biomed Eng
February 2015
Left ventricular assist devices (LVADs) are mechanical supports used in case of heart failure. Little is known as the height of the anastomosis in aorta might influence the hemodynamic. The aim of the study was to evaluate the fluid dynamic behavior due to the outflow graft placement of a continuous flow LVAD in ascending aorta and to identify the insertion site with the best hemodynamic profile.
View Article and Find Full Text PDFComput Methods Biomech Biomed Engin
January 2016
In the modern era, stroke remains a main cause of morbidity after cardiac surgery despite continuing improvements in the cardiopulmonary bypass (CPB) techniques. The aim of the current work was to numerically investigate the blood flow in aorta and epiaortic vessels during standard and pulsed CPB, obtained with the intra-aortic balloon pump (IABP). A multi-scale model, realized coupling a 3D computational fluid dynamics study with a 0D model, was developed and validated with in vivo data.
View Article and Find Full Text PDFBackground: This study reports the outcomes of patients who underwent electrical cardioversion for atrial fibrillation recurrence following mitral valve surgery and associated radiofrequency ablation compared to those who did not undergo concomitant atrial fibrillation ablation.
Methods: The population consisted of 116 patients with persistent/long-standing persistent AF who underwent mitral valve surgery with (Group A, n=54) or without (Group B, n=62) associated radiofrequency ablation between January 2007 and January 2011 at three institutions and who subsequently underwent cardioversion for persistent atrial fibrillation within 12 months of their initial procedure.
Results: The mean follow-up duration was 30.
Acute bowel ischemia is a perioperative complication that is frequently unrecognized as a cause of death after cardiac surgical procedures, with an in-hospital mortality of 50% to 100%. In recent years, controversy regarding the most appropriate approach to resolve clinical or laboratory suspicion and the limited therapeutic options have led to very little improvement in patient prognosis. This article reviews the related literature examining the actual prevalence, pathophysiologic mechanisms, predisposing factors, diagnostic tests, and therapeutic approaches providing a glance at new promising tools in diagnostic workup.
View Article and Find Full Text PDFA 60-year-old man underwent aortic and mitral valve replacement with mechanical On-X prostheses, plus tricuspid annuloplasty ring and maze radiofrequency ablation. Two years later, he was admitted to hospital with severe orthopnea and hemolysis. Echocardiography revealed a blocked prosthetic mitral leaflet due to interference of the preserved subvalvular apparatus.
View Article and Find Full Text PDFInteract Cardiovasc Thorac Surg
December 2013
Objectives: The revival of the apicoaortic conduit has attracted new interest in this alternative treatment for severe aortic stenosis unsuitable for conventional valve replacement. However, doubts still exist about the perfusion of the epiaortic vessels after apicoaortic conduit implantation, especially when severe aortic stenosis is associated with aortic valve insufficiency. The aim of the study was to evaluate the perfusion of the epiaortic vessels (innominate artery, left carotid artery and left subclavian artery) in cases of mixed aortic valve disease before and after apicoaortic conduit implantation.
View Article and Find Full Text PDFThe present study was undertaken to investigate, in an animal model, the relationship between sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) activity, phospholamban phosphorylation, acylphosphatase activity, and hemodynamic changes that occur in the early phase of pressure overload. In 54 study-group pigs, weighing 40±5 kg each, an aortic stenosis was created with a band of umbilical tape tied around the aorta; 18 sham-operated pigs formed our control group. Eight animals (6 study and 2 control) were randomly assigned to each experimental time (0.
View Article and Find Full Text PDF