Concentration and size distribution of atmospheric particles in southern Italy during COVID-19 lockdown period.

Many countries imposed lockdown (LD) to limit the spread of COVID-19, which led to a reduction in the emission of anthropogenic atmospheric pollutants. Several studies have investigated the effects of LD on air quality, mostly in urban settings and criteria pollutants. However, less information is available on background sites, and virtually no information is available on particle number size distribution (PNSD). This study investigated the effect of LD on air quality at an urban background site representing a near coast area in the central Mediterranean. The analysis focused on equivalent black carbon (eBC), particle mass concentrations in different size fractions: PM2.5 (aerodynamic diameter Da < 2.5 µm), PM10 (Da < 10 µm), PM10-2.5 (2.5 < Da < 10 µm); and PNSD in a wide range of diameters (0.01-10 µm). Measurements in 2020 during the national LD in Italy and period immediately after LD (POST-LD period) were compared with those in the corresponding periods from 2015 to 2019. The results showed that LD reduced the frequency and intensity of high-pollution events. Reductions were more relevant during POST-LD than during LD period for all variables, except quasi-ultrafine particles and PM10-2.5. Two events of long-range transport of dust were observed, which need to be identified and removed to determine the effect of LD. The decreases in the quasi-ultrafine particles and eBC concentrations were 20%, and 15-22%, respectively. PM2.5 concentration was reduced by 13-44% whereas PM10-2.5 concentration was unaffected. The concentration of accumulation mode particles followed the behaviour of PM2.5, with reductions of 19-57%. The results obtained could be relevant for future strategies aimed at improving air quality and understanding the processes that influence the number and mass particle size distributions.

On the concentration of SARS-CoV-2 in outdoor air and the interaction with pre-existing atmospheric particles.

The spread of SARS-CoV-2 by contact (direct or indirect) is widely accepted, but the relative importance of airborne transmission is still controversial. Probability of outdoor airborne transmission depends on several parameters, still rather uncertain: virus-laden aerosol concentrations, viability and lifetime, minimum dose necessary to transmit the disease. In this work, an estimate of outdoor concentrations in northern Italy (region Lombardia) was performed using a simple box model approach, based on an estimate of respiratory emissions, with a specific focus for the cities of Milan and Bergamo (Italy). In addition, the probability of interaction of virus-laden aerosol with pre-existing particles of different sizes was investigated. Results indicate very low (<1 RNA copy/m3) average outdoor concentrations in public area, excluding crowded zones, even in the worst case scenario and assuming a number of infects up to 25% of population. On average, assuming a number of infects equal to 10% of the population, the time necessary to inspire a quantum (i.e. the dose of airborne droplet nuclei required to cause infection in 63% of susceptible persons) would be 31.5 days in Milan (range 2.7-91 days) and 51.2 days in Bergamo (range 4.4-149 days). Therefore, the probability of airborne transmission due to respiratory aerosol is very low in outdoor conditions, even if it could be more relevant for community indoor environments, in which further studies are necessary to investigate the potential risks. We theoretically examined if atmospheric particles can scavenge virus aerosol, through inertial impact, interception, and Brownian diffusion. The probability was very low. In addition, the probability of coagulation of virus-laden aerosol with pre-existing atmospheric particles resulted negligible for accumulation and coarse mode particles, but virus-laden aerosol could act as sink of ultrafine particles (around 0.01 µm in diameter). However, this will not change significantly the dynamics behaviour of the virus particle or its permanence time in atmosphere.

Acute and Chronic Effects of Noninvasive Ventilation on Left and Right Myocardial Function in Patients with Obstructive Sleep Apnea Syndrome: A Speckle Tracking Echocardiographic Study.

BACKGROUND: In patients with obstructive sleep apnea syndrome (OSAS), repetitive hypoxia due to sleep-induced apnea adversely affects the interaction between myocardial oxygen demand and supply, resulting in the development of subclinical cardiac dysfunction. The purpose of the study was to analyze the different involvement of left and right heart myocardial function in patients with OSAS treated with noninvasive ventilation (NIV). METHODS: Conventional Doppler echocardiography, Doppler myocardial imaging (DMI), and two-dimensional speckle tracking echocardiography (2DSTE) of left (LV) and right ventricular (RV) longitudinal and right atrial (RA) deformation were performed in 55 patients with OSAS undergoing NIV (M/F 38/17; mean age 67.8 ± 11.2 years). LV and RV global longitudinal strain (GLS) was calculated by averaging local strain along the entire right and left ventricle, before and during NIV, and after 6 months of nocturnal NIV therapy. RESULTS: LV morphology was comparable before and during NIV, whereas LV ejection fraction and LV DMI early diastolic peak velocity were significantly improved in patients with OSAS during NIV, as was LV regional peak myocardial strain (P < 0.001). RV diameters were slightly increased in patients with OSAS during ventilation, whereas pulmonary artery systolic pressure (PASP), RV GLS, and regional peak myocardial RV strain were significantly reduced during ventilation (P < 0.0001). RA transverse diameters and RA area were also slightly increased during NIV, whereas RA lateral wall strain was reduced (P < 0.001). Acute RV myocardial impairment completely reversed at follow-up, with a decrease in PASP and subsequent increase in both RV and RA myocardial performance. CONCLUSIONS: Conventional 2DSTE is a useful tool for assessing left and right heart morphology and myocardial deformation in patients with OSAS and for monitoring both acute and chronic effects of NIV.

Inflammation and cardiovascular disease: from pathogenesis to therapeutic target.

Atherosclerosis represents the most common pathological substrate of coronary heart disease (CHD), and the characterization of the disease as a chronic low-grade inflammatory condition is now largely accepted. A number of mediators of inflammation have been widely studied, both as surrogate biomarkers and as causal agents, in the pathophysiological network of atherogenesis and plaque vulnerability. The epidemiological observation that biomarkers of inflammation are associated with clinical cardiovascular risk supports the theory that targeted anti-inflammatory treatment appears to be a promising strategy in reducing residual cardiovascular risk on the background of traditional medical therapy. A large number of randomized controlled trials have shown that drugs commonly used in cardiovascular disease (CVD), such as statins, may be effective in the primary and secondary prevention of cardiovascular events through an anti-inflammatory effect. Moreover, several anti-inflammatory drugs are being tested for their potential to reduce residual cardiovascular risk on the background of validated medical therapy for atherosclerotic disease. In this paper, we review relevant evidence with regard to the relationship between inflammation and CVD, from pathogenesis to therapeutic strategies.

Characterisation of the correlations between oxidative potential and in vitro biological effects of PM10 at three sites in the central Mediterranean.

Atmospheric particulate matter (PM) is one of the major risks for global health. The exact mechanisms of toxicity are still not completely understood leading to contrasting results when different toxicity metrics are compared. In this work, PM10 was collected at three sites for the determination of acellular oxidative potential (OP), intracellular oxidative stress (OSGC), cytotoxicity (MTT assay), and genotoxicity (Comet assay). The in vitro tests were done on the A549 cell line. The objective was to investigate the correlations among acellular and intracellular toxicity indicators, the variability among the sites, and how these correlations were influenced by the main sources by using PMF receptor model coupled with MLR. The OPDTTV, OSGCV, and cytotoxicity were strongly influenced by combustion sources. Advection of African dust led to lower-than-average intrinsic toxicity indicators. OPDTTV and OSGCV showed site-dependent correlations suggesting that acellular OP may not be fully representative of the intracellular oxidative stress at all sites and conditions. Cytotoxicity correlated with both OPDTTV and OSGCV at two sites out of three and the strength of the correlation was larger with OSGCV. Genotoxicity was correlated with cytotoxicity at all sites and correlated with both, OPDTTV and OSGCV, at two sites out of three. Results suggest that several toxicity indicators are useful to gain a global picture of the potential health effects of PM.

Airborne concentrations of SARS-CoV-2 in indoor community environments in Italy.

COVID-19 pandemic raised a debate regarding the role of airborne transmission. Information regarding virus-laden aerosol concentrations is still scarce in community indoors and what are the risks for general public and the efficiency of restriction policies. This work investigates, for the first time in Italy, the presence of SARS-CoV-2 RNA in air samples collected in different community indoors (one train station, two food markets, one canteen, one shopping centre, one hair salon, and one pharmacy) in three Italian cities: metropolitan city of Venice (NE of Italy), Bologna (central Italy), and Lecce (SE of Italy). Air samples were collected during the maximum spread of the second wave of pandemic in Italy (November and December 2020). All collected samples tested negative for the presence of SARS-CoV-2, using both real-time RT-PCR and ddPCR, and no significant differences were observed comparing samples taken with and without customers. Modelling average concentrations, using influx of customers' data and local epidemiological information, indicated low values (i.e. < 0.8 copies m-3 when cotton facemasks are used and even lower for surgical facemasks). The results, even if with some limitations, suggest that the restrictive policies enforced could effectively reduce the risk of airborne transmissions in the community indoor investigated, providing that physical distance is respected.

A review on measurements of SARS-CoV-2 genetic material in air in outdoor and indoor environments: Implication for airborne transmission.

Airborne transmission of SARS-CoV-2 has been object of debate in the scientific community since the beginning of COVID-19 pandemic. This mechanism of transmission could arise from virus-laden aerosol released by infected individuals and it is influenced by several factors. Among these, the concentration and size distribution of virus-laden particles play an important role. The knowledge regarding aerosol transmission increases as new evidence is collected in different studies, even if it is not yet available a standard protocol regarding air sampling and analysis, which can create difficulties in the interpretation and application of results. This work reports a systematic review of current knowledge gained by 73 published papers on experimental determination of SARS-CoV-2 RNA in air comparing different environments: outdoors, indoor hospitals and healthcare settings, and public community indoors. Selected papers furnished 77 datasets: outdoor studies (9/77, 11.7%) and indoor studies (68/77. 88.3%). The indoor datasets in hospitals were the vast majority (58/68, 85.3%), and the remaining (10/68, 14.7%) were classified as community indoors. The fraction of studies having positive samples, as well as positivity rates (i.e. ratios between positive and total samples) are significantly larger in hospitals compared to the other typologies of sites. Contamination of surfaces was more frequent (in indoor datasets) compared to contamination of air samples; however, the average positivity rate was lower compared to that of air. Concentrations of SARS-CoV-2 RNA in air were highly variables and, on average, lower in outdoors compared to indoors. Among indoors, concentrations in community indoors appear to be lower than those in hospitals and healthcare settings.

Physiologic Range of Myocardial Mechano-Energetic Efficiency among Healthy Subjects: Impact of Gender and Age.

BACKGROUND: Myocardial mechano-energetic efficiency (MEE) is the capability of the left ventricle (LV) to convert the chemical energy obtained from the cardiac oxidative metabolism into mechanical work. The aim of present study was to establish normal non-invasive MEE and MEEi reference values. METHODS: In total, 1168 healthy subjects underwent physical examinations, clinical assessment, and standardized transthoracic echocardiographic (TTE) examination. MEE was obtained by TTE as the ratio between stroke volume (SV) and heart rate (HR): MEE = SV/HR [HR expressed in seconds (HR/60)]. Because MEE is highly related to left ventricular mass (LVM), MEE was then divided by LVM with the purpose of obtaining an estimate of energetic expenditure per unit of myocardial mass (i.e., indexed MEE, MEEi, mL/s/g). RESULTS: The mean values of MEE and MEEi in the overall population were 61.09 ± 18.19 mL/s; 0.45 ± 0.14, respectively. In a multivariable analysis, gender, body surface area (BSA), diastolic blood pressure, left atrial volume indexed to BSA, E/e' and tricuspid annular plane systolic excursion (TAPSE) were the independent variables associated with MEE, while age, gender, BSA and TAPSE were the independent variables associated with MEEi. CONCLUSIONS: The knowledge of age- and gender-based MEE and MEEi normal values may improve the global assessment of LV cardiac mechanics and serve as a reference to identify phenotypes at high risk of cardiovascular events.

Characterization of airborne particulate fractions from the port city of Rijeka, Croatia.

The aim of this work was characterization of airborne particulates in the port city of Rijeka in order to evaluate impact of ship emissions on air quality. Samples of airborne particulates were collected with a ten stages cascade impactor during two campaigns: autumn and spring. A total of 16 weekly samples were analyzed on mass concentration, ions, metals and carbonaceous species (EC, OC, WSOC). Distribution of airborne fractions showed a bimodal distribution, with two maxima: one in coarse, and other in fine fraction. Source apportionment using PMF receptor model identified six sources of airborne particulates in Rijeka: crustal, biomass burning, sea salt, traffic/metal industry, combustion/SIA and HFO burning, i.e., ship emission (contribution 3%). The contribution of ship traffic to primary emission of particulate matter, using vanadium as tracer, indicated a twofold increase for PM10 and PM2.5 relative to 2012-14. An unusual desert dust event was registered in autumn campaign.

Size-resolved particle emission factors of vehicular traffic derived from urban eddy covariance measurements.

Road traffic is one of the major sources of atmospheric particles in urban areas. Modelling the contribution of this source to urban pollution requires reliable estimates of emission factors possibly resolved in size. In this work, size-resolved particle emission factors (EFs) of the mixed vehicle fleet were measured in the urban area of Lecce (south-eastern Italy). The approach used is based on vertical fluxes measured with eddy-covariance, counting of vehicles, and estimation of footprints. Results show that the average EF in number (range 0.009-3 µm) was 2.2*1014 #/Veh km, being dominated by ultrafine particles (Dp < 0.25 µm) due to exhaust emissions. EF number size distribution decreases with particle size. A reduction of more than four orders of magnitude was observed at Dp ≅ 0.9 µm. EF mass size distribution reaches a maximum around Dp ≅ 0.3 µm then decreases until Dp ≅ 0.9 µm. For larger particles EF in mass increases for the influence of non-exhaust emissions. Average emission factor of PM1 was 56 mg/Veh Km and that of PM2.5 was 63 mg/Veh Km. A comparison of measurements taken in 2010 and 2015 in the same area shows a decreasing trend of the average total EF in number of about 56%, likely as a consequence of the increased use of new generation vehicles following more restrictive limits for particle emissions.

Right Ventricular Functional Reserve in Early-Stage Idiopathic Pulmonary Fibrosis: An Exercise Two-Dimensional Speckle Tracking Doppler Echocardiography Study.

BACKGROUND: The most important determinant of long-term survival in patients with idiopathic pulmonary fibrosis is the right ventricular (RV) adaptation to the increased pulmonary vascular resistance. Our aim was to explore RV contractile reserve during stress echocardiography in early-stage IPF. METHODS: Fifty early-stage patients with IPF and 50 healthy control patients underwent rest and stress echocardiography, including RV two-dimensional speckle tracking echocardiography. At peak exertion, blood gas analysis and spirometry were also assessed. RESULTS: At rest, RV diameters were mildly increased in IPF; however, although RV conventional systolic function indexes were similar between the IPF and control groups, RV global longitudinal strain and RV lateral wall longitudinal strain (LWLS) were significantly reduced in the IPF cohort. During physical exercise, patients with IPF showed a reduced exercise tolerance with lower maximal workload (P < .01), level of oxygen saturation (P < .001), and peak heart rate (P < .01). Systolic and diastolic BP values were similar in both groups. Systolic pulmonary artery pressure (PAPs) increase (ΔPAPs) during exertion was higher in IPF vs healthy subjects (P < .0001); RV LWLS increase (ΔRV LWLS) during exercise was lower in patients with IPF vs control patients (P < .00001). By multivariable analysis, RV LWLS at rest and ΔRV LWLS were directly related to peak exertion capacity, PAPs, and blood oxygen saturation level (Spo2; P < .0001). Δ RV LWLS was directly related to diffusion lung carbon monoxide (P < .0001). CONCLUSIONS: RV myocardial dysfunction is already present at rest in early-stage IPF and worsens during exertion as detected by two-dimensional speckle-tracking echocardiography. The RV altered contractile reserve appears to be related to reduced exercise tolerability and impaired pulmonary hemodynamic.

Characterisation of particle size distributions and corresponding size-segregated turbulent fluxes simultaneously with CO2 exchange in an urban area.

Number and mass particle concentrations and fluxes were measured, simultaneously with CO2 concentration and flux, in the urban area of Lecce (Italy). The measurements of the turbulent exchanges of atmospheric particles and gas were performed with an eddy-covariance station located near the busiest road of the town. For the smaller particles, the diurnal evolution of the particle number concentrations and fluxes shows a clear correlation with human activities, in particular vehicular traffic, which is the obvious candidate as the source of the two clear peaks in the CPC concentration in the morning and in the evening. The fluxes were upward for all the measurement period, even though small net deposition was observed for larger particles and during weekend. For the CPC, the correlation with the traffic daily pattern is extremely strong. The city is a continuous particle source. The data analysis seems also to suggest the presence of local urban nucleation events. CO2 and particle concentrations were larger at low wind velocity, instead, fluxes were larger at high wind velocity. This opposite behaviour suggests that the influence of local urban emissions is larger on fluxes with respect to concentrations. The average daily patterns of CO2 concentration show an overlap between biogenic cycle and urban emissions. Again, traffic appears to be the dominant source for fluxes and the urban area is a net source of CO2.

Reference Ranges and Physiologic Variations of Left E/e' Ratio in Healthy Adults: Clinical and Echocardiographic Correlates.

BACKGROUND: Transthoracic Doppler echocardiographic examination is commonly performed to define the diastolic ventricular function since it is widely available, noninvasive, and inexpensive with respect to other diagnostic imaging modalities. However, data regarding age- and gender-matched reference values are scanty and sometimes conflicting. This study aims to explore the physiologic variations of left ventricular (LV) E/e' ratio as assessed in a large cohort of healthy adults and to investigate clinical and echocardiographic correlates. METHODS: From June 2007 to February 2014, 1168 healthy Caucasian adults (mean age 45.1 ± 15.6 years) performed standard echocardiographic examination (transthoracic echocardiogram). RESULTS: E/e' constantly increases across all the age classes (P < 0.0001, analyses of variance both for males and females) with a strong statistically significant linear positive correlation with age. Stepwise multiple linear regression analysis identified age (P < 0.0001), LV mass (P < 0.001), LV end-diastolic volume (P < 0.01), and left atrial volume (P < 0.001) as the only independent determinants of E/e' ratio (model R2 = 0.54, P < 0.0001). CONCLUSIONS: In healthy subjects, transmitral E velocity to e' ratio changes in relation to the age: it increased with a statistically significant correlation in individuals older than 60 years. Hence, differences related to demographic and anthropometric measurements may potentially develop a misclassification of otherwise normal individuals when established on dichotomically suggested normal reference values. Our study can demonstrate that it is indispensable to apply specific cutoff related to the age and gender to properly assess LV diastolic function.

Patient selection for transcatheter aortic valve replacement: A combined clinical and multimodality imaging approach.

Transcatheter aortic valve replacement (TAVR) has been validated as a new therapy for patients affected by severe symptomatic aortic stenosis who are not eligible for surgical intervention because of major contraindication or high operative risk. Patient selection for TAVR should be based not only on accurate assessment of aortic stenosis morphology, but also on several clinical and functional data. Multi-Imaging modalities should be preferred for assessing the anatomy and the dimensions of the aortic valve and annulus before TAVR. Ultrasounds represent the first line tool in evaluation of this patients giving detailed anatomic description of aortic valve complex and allowing estimating with enough reliability the hemodynamic entity of valvular stenosis. Angiography should be used to assess coronary involvement and plan a revascularization strategy before the implant. Multislice computed tomography play a central role as it can give anatomical details in order to choice the best fitting prosthesis, evaluate the morphology of the access path and detect other relevant comorbidities. Cardiovascular magnetic resonance and positron emission tomography are emergent modality helpful in aortic stenosis evaluation. The aim of this review is to give an overview on TAVR clinical and technical aspects essential for adequate selection.

Application of PMF and CMB receptor models for the evaluation of the contribution of a large coal-fired power plant to PM10 concentrations.

The evaluation of the contribution of coal-fired thermo-electrical power plants to particulate matter (PM) is important for environmental management, for evaluation of health risks, and for its potential influence on climate. The application of receptor models, based on chemical composition of PM, is not straightforward because the chemical profile of this source is loaded with Si and Al and it is collinear with the profile of crustal particles. In this work, a new methodology, based on Positive Matrix Factorization (PMF) receptor model and Si/Al diagnostic ratio, specifically developed to discriminate the coal-fired power plant contribution from the crustal contribution is discussed. The methodology was applied to daily PM10 samples collected in central Italy in proximity of a large coal-fired power plant. Samples were simultaneously collected at three sites between 2.8 and 5.8km from the power plant: an urban site, an urban background site, and a rural site. Chemical characterization included OC/EC concentrations, by thermo-optical method, ions concentrations (NH4(+), Ca(2+), Mg(2+), Na(+), K(+), Mg(2+), SO4(2-), NO3(-), Cl(-)), by high performances ion chromatography, and metals concentrations (Si, Al, Ti, V, Mn, Fe, Ni, Cu, Zn, Br), by Energy dispersive X-ray Fluorescence (ED-XRF). Results showed an average primary contribution of the power plant of 2% (±1%) in the area studied, with limited differences between the sites. Robustness of the methodology was tested inter-comparing the results with two independent evaluations: the first obtained using the Chemical Mass Balance (CMB) receptor model and the second correlating the Si-Al factor/source contribution of PMF with wind directions and Calpuff/Calmet dispersion model results. The contribution of the power plant to secondary ammonium sulphate was investigated using an approach that integrates dispersion model results and the receptor models (PMF and CMB), a sulphate contribution of 1.5% of PM10 (±0.3%) as average of the three sites was observed.

Transcranial Doppler Ultrasound: Physical Principles and Principal Applications in Neurocritical Care Unit.

Transcranial Doppler (TCD) ultrasonography is a noninvasive ultrasound study, which has been extensively applied on both outpatient and inpatient settings. It involves the use of a low-frequency (≤2 MHz) transducer, placed on the scalp, to insonate the basal cerebral arteries through relatively thin bone windows and to measure the cerebral blood flow velocity and its alteration in many different conditions. In neurointensive care setting, TCD is useful for both adults and children for day-to-day bedside assessment of critical conditions including vasospasm in subarachnoid hemorrhage, traumatic brain injury, acute ischemic stroke, and brain stem death. It also allows to investigate the cerebrovascular autoregulation in setting of carotid disease and syncope. In this review, we will describe physical principles underlying TCD, flow indices most frequently used in clinical practice and critical care applications in Neurocritical Unit care.

Transcranial Doppler Ultrasound: Incremental Diagnostic Role in Cryptogenic Stroke Part II.

Transcranial Doppler (TCD) ultrasonography is a noninvasive ultrasound study, which has been extensively applied in both outpatient and inpatient settings. Its main use in current clinical practice is the research for "Paradoxical Embolism," due to migration of thromboembolic material from systemic venous circulation to the left cardiac chambers and arterial circulation through cardiopulmonary shunts such as patent foramen ovale which represents an important cause of cryptogenic stroke, especially in patients under 55 years of age. In this review, we shall describe the incremental diagnostic role in cryptogenic stroke for this imaging modality. TCD not only can be used to detect right-left cardiopulmonary shunts but it also allows to classify the grade of severity of such shunts using the so-called "Microembolic Signals grading score."

Transcranial Doppler ultrasonography: From methodology to major clinical applications.

Non-invasive Doppler ultrasonographic study of cerebral arteries [transcranial Doppler (TCD)] has been extensively applied on both outpatient and inpatient settings. It is performed placing a low-frequency (≤ 2 MHz) transducer on the scalp of the patient over specific acoustic windows, in order to visualize the intracranial arterial vessels and to evaluate the cerebral blood flow velocity and its alteration in many different conditions. Nowadays the most widespread indication for TCD in outpatient setting is the research of right to left shunting, responsable of so called "paradoxical embolism", most often due to patency of foramen ovale which is responsable of the majority of cryptogenic strokes occuring in patients younger than 55 years old. TCD also allows to classify the grade of severity of such shunts using the so called "microembolic signal grading score". In addition TCD has found many useful applications in neurocritical care practice. It is useful on both adults and children for day-to-day bedside assessment of critical conditions including vasospasm in subarachnoidal haemorrhage (caused by aneurysm rupture or traumatic injury), traumatic brain injury, brain stem death. It is used also to evaluate cerebral hemodynamic changes after stroke. It also allows to investigate cerebral pressure autoregulation and for the clinical evaluation of cerebral autoregulatory reserve.