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Background There is a lack of data on extravascular lung water index (EVLWi), pulmonary vascular permeability index (PVPi), and global end-diastolic volume index (GEDVi) during prone position ventilation (PPV) in coronavirus disease 2019 (COVID-19) patients. The objectives of this study were to analyze trends in EVLWi, PVPi, and GEDVi during PPV and the relationships between these parameters and PaO2/FiO2. Methods In this preliminary retrospective observational study, we performed transpulmonary thermodilution (TPTD) in seven mechanically ventilated COVID-19 patients without cardiac and pulmonary comorbidities requiring PPV for 18 hours, at specific times (30 minutes pre-PPV, 18 hours after PPV, and 3 hours after supination). EVLWi, PVPi and GEDVi were measured. The relationships between PaO2/FiO2 and EVLWi, and PVPi and GEDVi values, in the supine position were analyzed by linear regression. Correlation and determination coefficients were calculated. Results EVLWi was significantly different between three time points (analysis of variance, P=0.004). After 18 hours in PPV, EVLWi was lower compared with values before PPV (12.7±0.9 ml/kg vs. 15.3±1.5 ml/kg, P=0.002). Linear regression showed that only EVLWi was correlated with PaO2/FiO2 (β =–5.757; 95% confidence interval, –10.835 to –0.679; r=–0.58; R2=0.34; F-test P=0.029). Conclusions EVLWi was significantly reduced after 18 hours in PPV and values measured in supine positions were correlated with PaO2/FiO2. This relationship can help clinicians discriminate whether deterioration in gas exchange is related to fluid overload or disease progression. Further clinical research should evaluate the role of TPTD parameters as markers to stratify disease severity and guide clinical management.

Typical radiological findings in patients with SARS-CoV-2 pneumonia consist of the presence of bilateral pulmonary opacities (both ground-glass attenuations and consolidations) with a peripheral or subpleural distribution, often involving the posterior regions of both lungs specifically. Although interstitial pneumonia represents the hallmark of COVID-19, the clinician should remember that sudden worsening gas exchange may have different aetiology. Pneumothorax and pneumomediastinum are well-known complications of invasive mechanical ventilation. However, since the beginning, the development of spontaneous pneumothorax and pneumomediastinum was reported in COVID-19 patients, without risk factors. The exact mechanism for the development of spontaneous pneumothorax and pneumomediastinum in COVID-19 patients is still unclear, and findings suggest that these clinical manifestations can be interpreted as an index of lung disease severity associated with complicated hospital courses, worst prognosis and increase in mortality rate. We report a case of a SARS-CoV-2 infected obese male patient, in quarantine and without risk factors, presenting to the emergency department for severe dyspnea due to COVID-19 pneumonia complicated by spontaneous pneumothorax and pneumomediastinum.

This study explores the potential of biomass hydrothermal carbonization (HTC) for developing innovative, integrated waste-to-value conversion chains. Experiments with two lignocellulosic residuals, silver fir sawdust (FIR) and wheat straw (STRAW), give valuable hints for foreshadowing novel process schemes. The batch carbonization reactions lasted from 0 to 120 min, at constant water/biomass ratios (FIR, 7/1; STRAW, 5/1), at 180, 200, and 230 °C, and autogenous pressure. Within the first 60 min of reaction, both biomasses release green platform chemicals in the liquid phase at increasing concentrations without resorting to catalysts or additives. Longer reaction times cause the depletion of liquid-phase chemicals due to secondary hydrochar production. The highest concentrations of 5-hydroxymethylfurfural (80 mM) and furfural (400 mM) detected with FIR suggest exploiting this biomass in a short-time HTC, renouncing the improvement of the solid fuel. Waste-to-energy is unanimously considered the route of choice for STRAW. In this case, the conventional use of HTC would be pre-treating the biomass for feeding a gasification stage properly. Evidence of this study suggests that a two-step HTC would combine the requirements of fuel production with those of recovery of value-added chemicals from the liquid phase. During the reactor warm-up to 230 °C, furfural concentration builds up to 300 mM, then halves within the first 15 min of the HTC process and drops to zero at 120 min, a reaction time required for a satisfactory STRAW energy densification (raw biomass, 15 MJ/kg; 120 min hydrochar, 21 MJ/kg). The results of this study pave the way for further investigation aiming to set the optimal operational conditions.

This paper introduces Bayesian statistical methods for studying the kinetics of biomass hydrothermal carbonization. Two simple, specially developed computer programs implement Markov-chain Monte Carlo methods to illustrate these techniques' potential, long since established in other areas of chemical reaction engineering. A range of experimental data, both from this study and the literature, test the soundness of a Bayesian approach to modeling biomass hydrothermal carbonization kinetics. The first program carries out parameter estimations and performs better or equal than the traditional deterministic methods (R2 as high as 0.9998). For three out of the 22 datasets, the program detected the global minima of the parameter space, while the deterministic least-square found local values. The second program uses Gillespie's algorithm for the statistical simulation of the reactions occurring in hydrothermal carbonization. Comparing six basic kinetic models with literature data tested the stochastic simulation as a tool for assessing biomass conversion reaction networks rapidly. Among the simple models discussed, reaction scheme 3 fitted better to the experimental data (R2 > 0.999). The proposed approach is worth extending to more complex, time-consuming computer models and could support other techniques for studying hydrothermal conversions.

An innovative process based on hydrothermal carbonization, gasification, and solid oxide fuel cells (SOFCs) technologies was developed using a commercial process simulation software called ASPEN Plus. The object of this work is to study plant efficiency under various operating conditions. The hydrothermal pre-treatment (HTC) at 200 and 250 °C was modelled as a black box based on the experimental results. The gasifier was modelled as a single reactor vessel with both the fluidized bed steam gasification of solid fuel and the hot gas cleaning system. The SOFC was modelled as a simple grey box with the ASPEN Plus blocks. The effect of HTC temperature and steam/carbon (S/C) ratio on the syngas composition and yield and plant efficiency was studied. The results show that the gasification of hydrochar obtained at 200 °C with S/C ratio of 0.6 gives the best results, namely an energy output of SOFC equal to 1.81 kW/kgBiomass, and overall process efficiency of 36%.

Contrarily to SARS and MERS, the evidence suggests that thromboembolic events are common in patients with COVID-19 pneumonia. The clinical course of severe COVID-19 patients can be complicated with coagulopathy, causing fatal thromboembolic events and requiring adequate treatment with anticoagulant therapy. However, the clinicians should be alerted about the increase of bleeding related to aggressive anticoagulation protocols, especially in critically ill patients who undergo traumatic maneuvers. Here, we reported the case of a 55-year-old woman with symptomatic COVID-19 pneumonia, admitted to the ICU and treated with anticoagulant therapy complicated by major bleeding, probably related to prone position for ARDS treatment.

This study aims to investigate the CO2 sorption capacity of hydrochar, obtained via hydrothermal carbonization (HTC). Silver fir sawdust was used as a model material. The batch runs went at 200 °C and up to 120 min. The hydrochar was activated with potassium hydroxide impregnation and subsequent thermal treatment (600 °C, 1 h). CO2 capture was assayed using a pressure swing adsorption (PSA) process. The morphology and porosity of hydrochar, characterized through Brunauer-Emmett-Teller, Barrett-Joyner-Halenda (BET-BJH) and scanning electron microscopy (SEM) analyses, were reported and the sorbent capacity was compared with traditional sorbents. The hydrochar recovered immediately after the warm-up of the HTC reactor had better performances. The Langmuir equilibrium isotherm fits the experimental data satisfactorily. Selectivity tests performed with a model biogas mixture indicated a possible use of hydrochar for sustainable upgrading of biogas to bio-methane. It is conceivably a new, feasible, and promising option for CO2 capture with low cost, environmentally friendly materials.

Background: There is a lack of data on extravascular lung water index (EVLWi), pulmonary vascular permeability index (PVPi), and global end-diastolic volume index (GEDVi) during prone position ventilation (PPV) in coronavirus disease 2019 (COVID-19) patients. The objectives of this study were to analyze trends in EVLWi, PVPi, and GEDVi during PPV and the relationships between these parameters and PaO2/FiO2. Methods: In this preliminary retrospective observational study, we performed transpulmonary thermodilution (TPTD) in seven mechanically ventilated COVID-19 patients without cardiac and pulmonary comorbidities requiring PPV for 18 hours, at specific times (30 minutes pre-PPV, 18 hours after PPV, and 3 hours after supination). EVLWi, PVPi and GEDVi were measured. The relationships between PaO2/FiO2 and EVLWi, and PVPi and GEDVi values, in the supine position were analyzed by linear regression. Correlation and determination coefficients were calculated. Results: EVLWi was significantly different between three time points (analysis of variance, P=0.004). After 18 hours in PPV, EVLWi was lower compared with values before PPV (12.7±0.9 ml/kg vs. 15.3±1.5 ml/kg, P=0.002). Linear regression showed that only EVLWi was correlated with PaO2/FiO2 (ß =-5.757; 95% confidence interval, -10.835 to -0.679; r=-0.58; R2=0.34; F-test P=0.029). Conclusions: EVLWi was significantly reduced after 18 hours in PPV and values measured in supine positions were correlated with PaO2/FiO2. This relationship can help clinicians discriminate whether deterioration in gas exchange is related to fluid overload or disease progression. Further clinical research should evaluate the role of TPTD parameters as markers to stratify disease severity and guide clinical management. [ABSTRACT FROM AUTHOR]

This study explores the potential of biomass hydrothermal carbonization (HTC) for developing innovative, integrated waste-to-value conversion chains. Experiments with two lignocellulosic residuals, silver fir sawdust (FIR) and wheat straw (STRAW), give valuable hints for foreshadowing novel process schemes. The batch carbonization reactions lasted from 0 to 120 min, at constant water/biomass ratios (FIR, 7/1; STRAW, 5/1), at 180, 200, and 230 °C, and autogenous pressure. Within the first 60 min of reaction, both biomasses release green platform chemicals in the liquid phase at increasing concentrations without resorting to catalysts or additives. Longer reaction times cause the depletion of liquid-phase chemicals due to secondary hydrochar production. The highest concentrations of 5-hydroxymethylfurfural (80 mM) and furfural (400 mM) detected with FIR suggest exploiting this biomass in a short-time HTC, renouncing the improvement of the solid fuel. Waste-to-energy is unanimously considered the route of choice for STRAW. In this case, the conventional use of HTC would be pre-treating the biomass for feeding a gasification stage properly. Evidence of this study suggests that a two-step HTC would combine the requirements of fuel production with those of recovery of value-added chemicals from the liquid phase. During the reactor warm-up to 230 °C, furfural concentration builds up to 300 mM, then halves within the first 15 min of the HTC process and drops to zero at 120 min, a reaction time required for a satisfactory STRAW energy densification (raw biomass, 15 MJ/kg; 120 min hydrochar, 21 MJ/kg). The results of this study pave the way for further investigation aiming to set the optimal operational conditions. [ABSTRACT FROM AUTHOR]

Typical radiological findings in patients with SARS-CoV-2 pneumonia consist of the presence of bilateral pulmonary opacities (both ground-glass attenuations and consolidations) with a peripheral or subpleural distribution, often involving the posterior regions of both lungs specifically. Although interstitial pneumonia represents the hallmark of COVID-19, the clinician should remember that sudden worsening gas exchange may have different aetiology. Pneumothorax and pneumomediastinum are well-known complications of invasive mechanical ventilation. However, since the beginning, the development of spontaneous pneumothorax and pneumomediastinum was reported in COVID-19 patients, without risk factors. The exact mechanism for the development of spontaneous pneumothorax and pneumomediastinum in COVID-19 patients is still unclear, and findings suggest that these clinical manifestations can be interpreted as an index of lung disease severity associated with complicated hospital courses, worst prognosis and increase in mortality rate. We report a case of a SARS-CoV-2 infected obese male patient, in quarantine and without risk factors, presenting to the emergency department for severe dyspnea due to COVID-19 pneumonia complicated by spontaneous pneumothorax and pneumomediastinum. [ABSTRACT FROM AUTHOR]

This study aims to investigate the CO2 sorption capacity of hydrochar, obtained via hydrothermal carbonization (HTC). Silver fir sawdust was used as a model material. The batch runs went at 200 °C and up to 120 min. The hydrochar was activated with potassium hydroxide impregnation and subsequent thermal treatment (600 °C, 1 h). CO2 capture was assayed using a pressure swing adsorption (PSA) process. The morphology and porosity of hydrochar, characterized through Brunauer-Emmett-Teller, Barrett-Joyner-Halenda (BET-BJH) and scanning electron microscopy (SEM) analyses, were reported and the sorbent capacity was compared with traditional sorbents. The hydrochar recovered immediately after the warm-up of the HTC reactor had better performances. The Langmuir equilibrium isotherm fits the experimental data satisfactorily. Selectivity tests performed with a model biogas mixture indicated a possible use of hydrochar for sustainable upgrading of biogas to bio-methane. It is conceivably a new, feasible, and promising option for CO2 capture with low cost, environmentally friendly materials. [ABSTRACT FROM AUTHOR]

A stirred tank membrane reactor is used to study the kinetics of polygalacturonic acid (PGA) enzymatic hydrolysis. The reactor operates in semicontinuous configuration:  the native biopolymer is loaded at the initial time and the system is continuously fed with the buffer. The effect of retention time (from 101 to 142 min) and membrane molecular weight cutoff (from 1 to 30 kDa) on the rate of permeable oligomers production is investigated. Reaction products are clustered in two different classes, those sized below the membrane cutoff and those above. The reducing power measured in the permeate is used as an estimate of total product concentration. The characteristic breakdown times range from 40 to 100 min. The overall kinetics obeys a first-order law with a characteristic time estimated to 24 min. New mathematical data handling are developed and illustrated using the experimental data obtained. Finally, the body of the experimental results suggests useful indications (reactor productivity, breakdown induction period) for implementing the bioprocess at the industrial scale. [ABSTRACT FROM AUTHOR]

The enzymatic depolymerization of the pectic substance polygalacturonic acid (PGA) is studied in batch reactor. The number-average molecular weight of native substrate is estimated, using a simple and quick technique, to be approximately 11.1 kDa, the polymeric chains consisting on average of 63 galacturonic acid units. The effect of enzyme concentration was studied varying biocatalyst loading from 6 to 242 mg/L. The experiments were repeated at substrate concentrations ranging from 0.5 to 5 g/L. Data obtained at both short reaction time (20 min) and prolonged enzyme action (up to 350 min) are correlated using different kinetic equations, and the parameter values are discussed. [ABSTRACT FROM AUTHOR]

Steam-exploded (SE) poplar wood biomass was hydrolyzed by means of a blend of Celluclast and Novozym cellulase complexes in the presence of the inhibiting compounds produced during the preceding steam-explosion pretreatment process. The SE temperature and time conditions were 214 °C and 6 min, resulting in a log R0 of 4.13. In enzymatic hydrolysis tests at 45 °C, the biomass loading in the bioreactor was 100 gDW/L (dry weight) and the enzyme-to-biomass ratio 0.06 g/gDW. The enzyme activities for endo-glucanase, exo-glucanase, and β-glucosidase were 5.76, 0.55, and 5.98 U/mg, respectively. The inhibiting effects of components released during SE (formic, acetic, and levulinic acids, furfural, 5-hydroxymethyl furfural (5-HMF), syringaldehyde, 4-hydroxy benzaldehyde, and vanillin) were studied at different concentrations in hydrolysis runs performed with rinsed SE biomass as model substrate. Acetic acid (2 g/L), furfural, 5-HMF, syringaldehyde, 4-hydroxybenzaldehyde, and vanillin (0.5 g/L) did not significantly effect the enzyme activity, whereas formic acid (11.5 g/L) inactivated the enzymes and levulinic acid (29.0 g/L) partially affected the cellulase. Synergism and cumulative concentration effects of these compounds were not detected. SSF experiments show that untreated SE biomass during the enzymatic attack gives rise to a nonfermentable hydrolysate, which becomes fermentable when rinsed SE biomass is used. The presence of acetic acid, vanillin, and 5-HMF (0.5 g/L) in SSF of 100 gDW /L biomass gave rise to ethanol yields of 84.0%, 73.5%, and 91.0% respectively, with respective lag phases of 42, 39, and 58 h. [ABSTRACT FROM AUTHOR]

An innovative process based on hydrothermal carbonization, gasification, and solid oxide fuel cells (SOFCs) technologies was developed using a commercial process simulation software called ASPEN Plus. The object of this work is to study plant efficiency under various operating conditions. The hydrothermal pre-treatment (HTC) at 200 and 250 °C was modelled as a black box based on the experimental results. The gasifier was modelled as a single reactor vessel with both the fluidized bed steam gasification of solid fuel and the hot gas cleaning system. The SOFC was modelled as a simple grey box with the ASPEN Plus blocks. The effect of HTC temperature and steam/carbon (S/C) ratio on the syngas composition and yield and plant efficiency was studied. The results show that the gasification of hydrochar obtained at 200 °C with S/C ratio of 0.6 gives the best results, namely an energy output of SOFC equal to 1.81 kW/kgBiomass, and overall process efficiency of 36%. [ABSTRACT FROM AUTHOR]