Innovative manufacturing process of functionalized PA2200 for reduced adhesion properties

This work proposes an approach to fabricate micro patterned surfaces on PA2200 polyamide in order to improve its performance in terms of wettability and adhesion. In more detail, the present work aims to change the wettability of the surface and decrease their bacteria adhesion tendency. The experimental procedure consists of imprinting a set of different micro patterned structures over the polymer in order to verify the effectiveness of the methodology to change the contact angle of the surface, and in turn, reduce the occurrence of bacteria adhesion. Four different surface patterning were produced by laser ablation of a commercially pure titanium alloy, and then imprinted over the polyamide by surface stamping. The resulting surfaces were analyzed by topographical characterization and scanning electron microscopy. The wettability was probed by contact angle measurements while the bacteria adhesion was analyzed by adhesion test. The experimental results demonstrate the effectiveness of the method to modify the surface characteristics and to obtain a reliable patterned surface without using chemical hazardous material; opening to the possibility to replicate more complex structures and to obtain graded engineering surfaces

Tidal volume in acute respiratory distress syndrome : how best to select it

Mechanical ventilation is the type of organ support most widely provided in the intensive care unit. However, this form of support does not constitute a cure for acute respiratory distress syndrome (ARDS), as it mainly works by buying time for the lungs to heal while contributing to the maintenance of vital gas exchange. Moreover, it can further damage the lung, leading to the development of a particular form of lung injury named ventilator-induced lung injury (VILI). Experimental evidence accumulated over the last 30 years highlighted the factors associated with an injurious form of mechanical ventilation. The present paper illustrates the physiological effects of delivering a tidal volume to the lungs of patients with ARDS, and suggests an approach to tidal volume selection. The relationship between tidal volume and the development of VILI, the so called volotrauma, will be reviewed. The still actual suggestion of a lung-protective ventilatory strategy based on the use of low tidal volumes scaled to the predicted body weight (PBW) will be presented, together with newer strategies such as the use of airway driving pressure as a surrogate for the amount of ventilatable lung tissue or the concept of strain, i.e., the ratio between the tidal volume delivered relative to the resting condition, that is the functional residual capacity (FRC). An ultra-low tidal volume strategy with the use of extracorporeal carbon dioxide removal (ECCO2R) will be presented and discussed. Eventually, the role of other ventilator-related parameters in the generation of VILI will be considered (namely, plateau pressure, airway driving pressure, respiratory rate (RR), inspiratory flow), and the promising unifying framework of mechanical power will be presented

Tidal volume in acute respiratory distress syndrome : how best to select it

Mechanical ventilation is the type of organ support most widely provided in the intensive care unit. However, this form of support does not constitute a cure for acute respiratory distress syndrome (ARDS), as it mainly works by buying time for the lungs to heal while contributing to the maintenance of vital gas exchange. Moreover, it can further damage the lung, leading to the development of a particular form of lung injury named ventilator-induced lung injury (VILI). Experimental evidence accumulated over the last 30 years highlighted the factors associated with an injurious form of mechanical ventilation. The present paper illustrates the physiological effects of delivering a tidal volume to the lungs of patients with ARDS, and suggests an approach to tidal volume selection. The relationship between tidal volume and the development of VILI, the so called volotrauma, will be reviewed. The still actual suggestion of a lung-protective ventilatory strategy based on the use of low tidal volumes scaled to the predicted body weight (PBW) will be presented, together with newer strategies such as the use of airway driving pressure as a surrogate for the amount of ventilatable lung tissue or the concept of strain, i.e., the ratio between the tidal volume delivered relative to the resting condition, that is the functional residual capacity (FRC). An ultra-low tidal volume strategy with the use of extracorporeal carbon dioxide removal (ECCO2R) will be presented and discussed. Eventually, the role of other ventilator-related parameters in the generation of VILI will be considered (namely, plateau pressure, airway driving pressure, respiratory rate (RR), inspiratory flow), and the promising unifying framework of mechanical power will be presented

Current concepts of ARDS : a narrative review

Acute respiratory distress syndrome (ARDS) is characterized by the acute onset of pulmonary edema of non-cardiogenic origin, along with bilateral pulmonary infiltrates and reduction in respiratory system compliance. The hallmark of the syndrome is refractory hypoxemia. Despite its first description dates back in the late 1970s, a new definition has recently been proposed. However, the definition remains based on clinical characteristic. In the present review, the diagnostic workup and the pathophysiology of the syndrome will be presented. Therapeutic approaches to ARDS, including lung protective ventilation, prone positioning, neuromuscular blockade, inhaled vasodilators, corticosteroids and recruitment manoeuvres will be reviewed. We will underline how a holistic framework of respiratory and hemodynamic support should be provided to patients with ARDS, aiming to ensure adequate gas exchange by promoting lung recruitment while minimizing the risk of ventilator-induced lung injury. To do so, lung recruitability should be considered, as well as the avoidance of lung overstress by monitoring transpulmonary pressure or airway driving pressure. In the most severe cases, neuromuscular blockade, prone positioning, and extra-corporeal life support (alone or in combination) should be taken into account

2D FE Prediction of Surface Alteration of Inconel 718 under Machining Condition

Abstract Nickel-based super alloys such as Inconel 718 are widely employed in extremely hostile applications owing to their superior thermo-mechanical properties. On the contrary, these latter lead the industries to adopt conservative process parameters (e.g. low cutting speed) resulting in lower production rates. The possibility to increase the cutting parameters could lead to higher material removal rates and drastic reduction of the machining time of the process. The aim of this study is to investigate the effects of extreme cutting parameters on the surface and subsurface alterations such as grain size and hardness changes by developing a finite element (FE) numerical model. The Zener-Hollomon and Hall-Petch equation were implemented to predict the grain size and micro hardness variations due to the cutting process. In addition, the depth of the affected layer due to machining was predicted using the critical strain equation. The obtained results proved the accuracy and reliability of the proposed FE model showing a good agreement between the simulated and the experimental results

Systemic capillary leak syndrome : is methylene blue the silver bullet?

Background. Systemic capillary leak syndrome (SCLS) is a rare disorder characterized by unexplained, recurrent episodes of transient, abrupt increase in endothelial permeability, leading to severe hypotension, generalized edema, and hemoconcentration. Case Report. We report the case of a patient suffering from systemic capillary leak syndrome and present a possible interpretation of the pathophysiology of this condition. Besides the classical triad of hypotension, edema, and hemoconcentration, we recorded increased levels of methemoglobin, an index of NO overproduction. We present a possible interpretation of the pathophysiology of this condition based on the fast and complete reversal of symptoms after methylene blue administration (which opposes NO-induced effects) and speculate that increased NO levels could be implicated in the pathophysiology of the capillary leak phase. Why should an emergency physician be aware of this? The safety of this treatment and its fluid- and cathecolamine-sparing effect deserve consideration and further research

Neutrophil activation in systemic capillary leak syndrome (Clarkson disease)

Systemic capillary leak syndrome (SCLS; Clarkson disease) is a rare orphan disorder characterized by transient yet recurrent episodes of hypotension and peripheral oedema due to diffuse vascular leakage of fluids and proteins into soft tissues. Humoral mediators, cellular responses and genetic features accounting for the clinical phenotype of SCLS are virtually unknown. Here, we searched for factors altered in acute SCLS plasma relative to matched convalescent samples using multiplexed aptamer‐based proteomic screening. Relative amounts of 612 proteins were changed greater than twofold and 81 proteins were changed at least threefold. Among the most enriched proteins in acute SCLS plasma were neutrophil granule components including bactericidal permeability inducing protein, myeloperoxidase and matrix metalloproteinase 8. Neutrophils isolated from blood of subjects with SCLS or healthy controls responded similarly to routine pro‐inflammatory mediators. However, acute SCLS sera activated neutrophils relative to remission sera. Activated neutrophil supernatants increased permeability of endothelial cells from both controls and SCLS subjects equivalently. Our results suggest systemic neutrophil degranulation during SCLS acute flares, which may contribute to the clinical manifestations of acute vascular leak

Stressors in the ICU: different perceptions of patients, relatives and staff members

Introduction The high-risk critically ill are exposed to signifi cant stressors, along with diffi culties in communicating them to relatives and members of the staff . The aim of this study was to compare the perception of stressors as reported by patients (P), relatives (R) and ICU staff members (S). Methods A validated questionnaire [1] was used to quantitatively assess discomforts related to the ICU stay. Items were clustered into categories; higher scores refer to a higher stressfulness. The median (IQR) was calculated for each category. Twenty-eight high-risk critically ill at discharge, 55 relatives 48 hours after admission of their next of kin, and a total of 125 staff members (55 attending physicians, 40 nurses and 30 medical students/specialist trainees) were interviewed. Fifty-six of the staff members were used to keep patients consciously sedated as for local guidelines; the remaining used deeper levels of sedation. Nonparametric tests were used as needed. Results All stressor categories were diff erently reported by the three groups analysed: environmental (S = 17 (15 to 19), R = 15 (13 to 18), P = 10 (8 to 11), P <0.01), relationships (S = 23 (21 to 25), R = 20.5 (17 to 24.5), P = 14 (11 to 17), P <0.01), emotional (S = 25.5 (23 to 28), R = 24 (20 to 26), P = 18 (15 to 22), P <0.01), and physical (S = 35 (31 to 38), R = 33 (26.5 to 37), P = 27 (21 to 30), P <0.01). Among the staff members, nurses overestimated more than attending physicians, while trainees are closer to relatives\u2019 perception (P = 0.03). Staff members used to conscious sedation overestimate less the impact of environmental stressors (P = 0.03). Years of experience (r = 0.24, P = 0.03) and age (r = 0.27, P = 0.01) are related to stressor overestimation among staff members. Conclusion Members of the staff should reconsider their beliefs on patients\u2019 perception of stressors. We argue that such an overestimation may bring inappropriate administration of analgesic and sedative drugs, particularly for nurses and older members of staff . Relatives might be useful intermediaries to have a better insight of patients\u2019 perception