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Search Results: 1 - 10 of 209144 matches for " Raffaele L Dellacà "
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Changes in the mechanical properties of the respiratory system during the development of interstitial lung edema
Raffaele L Dellacà, Emanuela Zannin, Giulio Sancini, Ilaria Rivolta, Biagio E Leone, Antonio Pedotti, Giuseppe Miserocchi
Respiratory Research , 2008, DOI: 10.1186/1465-9921-9-51
Abstract: We studied 17 paralysed and mechanically ventilated closed-chest rats (325–375 g). Total input respiratory system impedance (Zrs) was derived from tracheal flow and pressure signals by applying forced oscillations with frequency components from 0.16 to 18.44 Hz distributed in two forcing signals. In 8 animals interstitial lung edema was induced by intravenous infusion of saline solution (0.75 ml/kg/min) for 4 hours; 9 control animals were studied with the same protocol but without infusion. Zrs was measured at the beginning and every 15 min until the end of the experiment.In the treated group the lung wet-to-dry weight ratio increased from 4.3 ± 0.72 to 5.23 ± 0.59, with no histological signs of alveolar flooding. Resistance (Rrs) increased in both groups over time, but to a greater extent in the treated group. Reactance (Xrs) did not change in the control group, while it decreased significantly at all frequencies but one in the treated. Significant changes in Rrs and Xrs were observed starting after ~135 min from the beginning of the infusion. By applying a constant phase model to partition airways and tissue mechanical properties, we observed a mild increase in airways resistance in both groups. A greater and significant increase in tissue damping (from 603.5 ± 100.3 to 714.5 ± 81.9 cmH2O/L) and elastance (from 4160.2 ± 462.6 to 5018.2 ± 622.5 cmH2O/L) was found only in the treated group.These results suggest that interstitial edema has a small but significant impact on the mechanical features of lung tissues and that these changes begin at very early stages, before the beginning of accumulation of extravascular fluid into the alveoli.The functional organisation of the lung extracellular matrix comprises basically two large macromolecular families. The fibrillar components, including collagen I and III and elastic fibers, provide the elasticity of the lung tissue on stretching and de-stretching which is mechanically defined as lung compliance, that is the ratio be
The Abdominal Circulatory Pump
Andrea Aliverti, Dario Bovio, Irene Fullin, Raffaele L. Dellacà, Antonella Lo Mauro, Antonio Pedotti, Peter T. Macklem
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0005550
Abstract: Blood in the splanchnic vasculature can be transferred to the extremities. We quantified such blood shifts in normal subjects by measuring trunk volume by optoelectronic plethysmography, simultaneously with changes in body volume by whole body plethysmography during contractions of the diaphragm and abdominal muscles. Trunk volume changes with blood shifts, but body volume does not so that the blood volume shifted between trunk and extremities (Vbs) is the difference between changes in trunk and body volume. This is so because both trunk and body volume change identically with breathing and gas expansion or compression. During tidal breathing Vbs was 50–75 ml with an ejection fraction of 4–6% and an output of 750–1500 ml/min. Step increases in abdominal pressure resulted in rapid emptying presumably from the liver with a time constant of 0.61±0.1SE sec. followed by slower flow from non-hepatic viscera. The filling time constant was 0.57±0.09SE sec. Splanchnic emptying shifted up to 650 ml blood. With emptying, the increased hepatic vein flow increases the blood pressure at its entry into the inferior vena cava (IVC) and abolishes the pressure gradient producing flow between the femoral vein and the IVC inducing blood pooling in the legs. The findings are important for exercise because the larger the Vbs the greater the perfusion of locomotor muscles. During asystolic cardiac arrest we calculate that appropriate timing of abdominal compression could produce an output of 6 L/min. so that the abdominal circulatory pump might act as an auxiliary heart.
Chest wall mechanics during pressure support ventilation
Andrea Aliverti, Eleonora Carlesso, Raffaele Dellacà, Paolo Pelosi, Davide Chiumello, Antonio Pedotti, Luciano Gattinoni
Critical Care , 2006, DOI: 10.1186/cc4867
Abstract: In nine patients four different levels of PSV (5, 10, 15 and 25 cmH2O) were randomly applied with the same level of positive end-expiratory pressure (10 cmH2O). Flow, airway opening, and oesophageal and gastric pressures were measured, and volume variations for the entire chest wall, the ribcage and abdominal compartments were recorded by opto-electronic plethysmography. The pressure and the work generated by the diaphragm, rib cage and abdominal muscles were determined using dynamic pressure-volume loops in the various phases of each respiratory cycle: pre-triggering, post-triggering with the patient's effort combining with the action of the ventilator, pressurization and expiration. The complete breathing pattern was measured and correlated with chest wall kinematics and dynamics.At the various levels of pressure support applied, minute ventilation was constant, with large variations in breathing frequency/ tidal volume ratio. At pressure support levels below 15 cmH2O the following increased: the pressure developed by the inspiratory muscles, the contribution of the rib cage compartment to the total tidal volume, the phase shift between rib cage and abdominal compartments, the post-inspiratory action of the inspiratory rib cage muscles, and the expiratory muscle activity.During PSV, the ventilatory pattern is very different at different levels of pressure support; in patients with acute lung injury pressure support greater than 10 cmH2O permits homogeneous recruitment of respiratory muscles, with resulting synchronous thoraco-abdominal expansion.In intensive care pressure support ventilation (PSV), a form of assisted mechanical ventilation, is among the modes most commonly employed to decrease the patient's work of breathing without neuromuscular blockade [1]. It is known that for optimal unloading of the respiratory muscles, the ventilator should cycle in synchrony with the activity of the patient's respiratory rhythm. Patient-ventilator asynchrony frequently occ
The blood shifts during the pressure volume curve
D Chiumello, A Aliverti, R Dellacà, E Carlesso, L Gattinoni
Critical Care , 2002, DOI: 10.1186/cc1552
Abstract: In eight sedated and paralyzed ALI/ARDS patients (5 M/3 F, age 75 ± 13 years, BMI 25.6 ± 3 kg/m2, PaO2/FiO2 222 ± 67 mmHg), the PV curves were obtained by the supersyringe method. A mathematical correction was applied to the gas volume injected or withdrawn by the syringe to avoid mistakes due to temperature, humidity, pressure and gas exchange [2]. To study the deflation phase, avoiding the inflation effects, for each PV curve the difference between the total static compliance (TSC) of PVgas and TSC of PVcw, was added to the deflation limb of PVcw.(1) Inflation phase: the ?Vgas was always higher than the Vcw, the discrepancy between ?Vgas and ?Vcw was at TSC -193.72 ± 145.56 ml, which was correlated to airway pressure product time of inflation (P < 0.001, r2 = 0.87) and to the ratio between esophageal and airway pressure variations (?Pes/?Paw) (P < 0.01, r2 = 0.91).(2) Deflation phase: the ?Vgas was equal, lower or higher than the ?Vcw, this discrepancy was correlated to central venous pressure (P < 0.01, r2 = 0.7) and time to deflation (P < 0.05, r2 = 0.8).The discrepancy between ?Vgas and ?Vcw was correlated to time to perform the PV curve, airway pressure reached, mechanical property of the respiratory system and hemodynamic conditions. We think that the discrepancy can be due to the blood shifts (OUT and INTO the thorax).
Obesity, Diabetes Mellitus and Vascular Disease: A Complex Relationship with Prostate Cancer  [PDF]
Simona Di Francesco, Raffaele L. Tenaglia
Journal of Cancer Therapy (JCT) , 2014, DOI: 10.4236/jct.2014.55050
Abstract:

Background: Obesity, type II Diabetes mellitus (DMII) and vascular damage could be implicated in prostate cancer (PCa) nevertheless no clear results has been reached. The aim of the research was to investigate the association of these alterations with PCa at initial diagnosis, without the influence of hormone therapy or chemotherapy. Methods: Retrospective analysis of 400 patients undergoing prostate biopsy at our institution between 2005 and 2012 was conducted. We examined associations of obesity, DMII and vascular damage in 200 patients with PCa diagnosis versus 200 age-matched controls. Men with history of hormone therapy or chemotherapy, prostate or bladder surgery were excluded. Results: Obesity was significantly associated (OR 2.10, p < 0.05) with aggressive PCa (Gleason Score 8 - 10). DMII was significantly associated to aggressive PCa but only in obese cases (OR 4.25). Carotid vascular disease (CVD) and coronary artery disease (CAD) were significantly linked to PCa in all cases versus controls (OR 1.88, p < 0.05). Conclusions: In our study, obesity, particularly in combination with DMII, was significantly associated with aggressive PCa. Moreover, a significant relation was found between vascular disease and PCa hormone-naive at initial diagnosis. The metabolic derangements associated to obesity and DMII may increase oxidative stress and cause a permanent pro-inflammatory state that predisposes to vascular disease and PCa.

On the New Boson Higgs’s Studies at the CERN-ATLAS Experiment. The Emergency of a Historical Discovery  [PDF]
Raffaele Pisano
Advances in Historical Studies (AHS) , 2013, DOI: 10.4236/ahs.2013.21002
Abstract: This paper is a summary of the interview-workshop to Aleandro Nisati (12 December 2012, SEMM-Service Enseignement et Multimédia) co-organized by UFR Physique, University of Lille 1, France (Raffaele Pisano, Remi Franckowiak, Bernard Maitte and Lisa Rougetet), ATLAS Experiment Team (CERN, Genève, Switzerland), in persons of the cited Italian scientist—already Physics coordinator at ATLAS—and his colleague, Steven Goldfarb (CERN-University of Michigan, USA). The latter kindly answered to the questions on the ATLAS detector, LHC machine and CERN-ATLAS laboratories proposed by the participants. Distinguished lectures by historians of science at University of Lille 1 (Bernard Maitte, Bernard Pourprix and Robert Locqueneux) specialist on history of physics opened the workshop session.
Review Ph.D. Thesis: Psyco-Education Factors of Applying Visualisation in Science Education. Siauliai University, Lithuania  [PDF]
Raffaele Pisano
Advances in Historical Studies (AHS) , 2013, DOI: 10.4236/ahs.2013.21005
Abstract: This paper presents a review of a Ph.D. Thesis by Renata Bilbokaite, Natural Science Education Research Centre, Siauliai University, Lithuania.
Reflections on the Scientific Conceptual Streams in Leonardo da Vinci and His Relationship with Luca Pacioli  [PDF]
Raffaele Pisano
Advances in Historical Studies (AHS) , 2013, DOI: 10.4236/ahs.2013.22007
Abstract: Leonardo da Vinci (1452-1519) is perhaps overrated for his contributions to physical science, since his technical approach. Nevertheless important components concerning practical problems of mechanics with great technical ability were abounded. He brought alive again the Nemorarius’ (fl. 12th - 13th century) tradition and his speculations on mechanics, if immature made known how difficult and elusive were the conceptual streams of the foundations of science for practitioners-artisans. Leonardo also had an interesting and intense relationship with mathematics but merely unhappy insights in his time. The meeting with Luca Bartolomeo de Pacioli (1445-1517) was very important for da Vinci since proposing stimulating speculations were implemented, but they were not definitive theoretical results. In this paper historical reflections notes on mechanics and mathematics in da Vinci and his relationships with Pacioli are presented.
Introduction to Advances Historical Studies—Newton Special Issue. History and Historical Epistemology of Science  [PDF]
Raffaele Pisano
Advances in Historical Studies (AHS) , 2014, DOI: 10.4236/ahs.2014.31001
Abstract: Introduction to Advances Historical Studies
Solutions to the Boltzmann equation in the Boussinesq regime
Raffaele Esposito,Joel L. Lebowitz,Rossana Marra
Physics , 1997, DOI: 10.1023/A:1023223226585
Abstract: We consider a gas in a horizontal slab, in which the top and bottom walls are kept at different temperatures. The system is described by the Boltzmann equation (BE) with Maxwellian boundary conditions specifying the wall temperatures. We study the behavior of the system when the Knudsen number $\epsilon$ is small and the temperature difference between the walls as well as the velocity field is of order $\epsilon$, while the gravitational force is of order $\epsilon^2$. We prove that there exists a solution to the BE for which is near a global Maxwellian, and whose moments are close, up to order $\epsilon^2$ to the density, velocity and temperature obtained from the smooth solution of the Oberbeck-Boussinesq equations, up to the time this one stays regular.
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