Optical Absorptivity versus Molecular Composition of Model Organic Aerosol Matter

Aerosol particles affect the Earth’s energy balance by absorbing and scattering radiation according to their chemical composition, size, and shape. It is generally believed that their optical properties could be deduced from the molecular composition of the complex organic matter contained in these particles, a goal pursued by many groups via high-resolution mass spectrometry, although: (1) absorptivity is associated with structural chromophores rather than with molecular formulas, (2) compositional space is a small projection of structural space, and (3) mixtures of polar polyfunctional species usually exhibit supramolecular interactions. Here we report a suite of experiments showing that the photolysis of aqueous pyruvic acid (a proxy for aerosol α-dicarbonyls absorbing at λ > 300 nm) generates mixtures of identifiable aliphatic polyfunctional oligomers that develop absorptions in the visible upon standing in the dark. These absorptions and their induced fluorescence emissions can be repeatedly bleached and retrieved without carbon loss or ostensible changes in the electrospray mass spectra of the corresponding mixtures and display unambiguous signatures of supramolecular effects. The nonlinear additivity of the properties of the components of these mixtures supports the notion that full structural speciation is insufficient and possibly unnecessary for understanding the optical properties of aerosol particles and their responses to changing ambient conditions

Thermochromism of Model Organic Aerosol Matter

Laboratory experiments show that the optical absorptivity of model organic matter is not an intrinsic property, but a strong function of relative humidity, temperature, and insolation. Suites of representative polyfunctional C_(x)H_(y)O_(z) oligomers in water develop intense visible absorptions upon addition of inert electrolytes. The resulting mixtures reach mass absorption cross sections σ(532 nm) ~ 0.1 m^(2)/gC in a few hours, absorb up to 9 times more solar radiation than the starting material, can be half-bleached by noon sunlight in ~ 1 h, and can be repeatedly recycled without carbon loss. Visible absorptions red-shift and evolve increasingly faster in subsequent thermal aging cycles. Thermochromism and its strong direct dependences on ionic strength and temperature are ascribed to the dehydration of >CH−C(OH)C═C< unsaturations by a polar E1 mechanism, and bleaching to photoinduced retrohydration. These transformations are deemed to underlie the daily cycles of aerosol absorption observed in the field, and may introduce a key feedback in the earth’s radiative balance

Lo "Stone Center": quali il suo ruolo, la sua strutturazione e la sua collocazione, oggi

Abstract non disponibil

COVID-19 Accelerated Cognitive Decline in Elderly Patients with Pre-Existing Dementia Followed up in an Outpatient Memory Care Facility

Introduction: Coronavirus disease 2019 (COVID-19) may affect the cognitive function and activities of daily living (ADL) of elderly patients. This study aimed to establish the COVID-19 effect on cognitive decline and the velocity of cognitive function and ADL changes in elderly patients with dementia followed up in an outpatient memory care facility. Methods: In total, 111 consecutive patients (age 82 ± 5 years, 32% males) with a baseline visit before infection were divided into those who had or did not have COVID-19. Cognitive decline was defined as a five-point loss of Mini-Mental State Examination (MMSE) score and ADL comprising basic and instrumental ADL indexes (BADL and IADL, respectively). COVID-19 effect on cognitive decline was weighted for confounding variables by the propensity score, whereas the effect on change in the MMSE score and ADL indexes was analyzed using multivariate mixed-effect linear regression. Results: COVID-19 occurred in 31 patients and a cognitive decline in 44. Cognitive decline was about three and a half times more frequent in patients who had COVID-19 (weighted hazard ratio 3.56, 95% confidence interval 1.50–8.59, p = 0.004). The MMSE score lowered on average by 1.7 points/year, independently of COVID-19, but it lowered twice faster in those who had COVID-19 (3.3 vs. 1.7 points/year, respectively, p < 0.050). BADL and IADL indexes lowered on average less than 1 point/year, independently of COVID-19 occurrence. Patients who had COVID-19 had a higher incidence of new institutionalization than those who did not have the disease (45% versus 20%, p = 0.016, respectively). Conclusions: COVID-19 had a significant impact on cognitive decline and accelerated MMSE reduction in elderly patients with dementia

Menu labelling and healthy food choices: a randomised controlled trial

The purpose of this study was to examine the effect of different menu labelling formats on healthy food choices in a real restaurant setting. This cross-sectional, randomised and controlled parallel-group trial was conducted in Brazil in 2013. 313 university students were randomly assigned to one of three parallel groups with different menu labelling formats. Of these, data from 233 students were analysed. The others did not attend and were excluded. Intervention group 1 (n=88) received information in the form of a traffic light system plus guideline daily amounts, while intervention group 2 (n=74) was presented with an ingredients list plus highlighted symbols. The control group (n=71) received a menu with no menu labelling. Data were collected on one weekday in a restaurant setting. Trial outcomes were assessed by healthy food choices. Healthy food choices were significantly higher among students who received the menu showing an ingredients list plus highlighted symbols. The same menu labelling format positively affected healthy food choices in women, not overweight participants and who often ate out more than twice a week. A menu labelling format that presented an ingredients list and highlighted symbols was positively associated with healthy food choices among university students in Brazil. This type of labelling could be adopted in future legislation on menu labelling in Brazil and around the world

Polyphenols rich diets and risk of type 2 diabetes

Type 2 diabetes is an increasing health concern worldwide. Both genetic and environmental risk factors as improper dietary habits or physical inactivity are known to be crucial in the pathogen-esis of type 2 diabetes. Polyphenols are a group of plant-derived compounds with anti-inflammatory and antioxidant properties that are associated with a low prevalence of metabolic conditions charac-terized by insulin resistance, including obesity, diabetes, and hypertension. Moreover, there is now full awareness that foods that are rich in phytochemicals and polyphenols could play an important role in preserving human cardiovascular health and substantial clinical evidence indicates that regu-lar dietary consumption of such foods affects favorably carbohydrate metabolism. This review briefly summarizes the evidence relating dietary patterns rich in polyphenols with glucose metabolism and highlights the potential benefits of these compounds in the prevention of type 2 diabetes

Sustained virologic response to direct-acting antiviral agents predicts better outcomes in hepatitis C virus-infected patients: A retrospective study

Direct-acting antiviral agents (DAAs) are extremely effective in eradicating hepatitis C virus (HCV) in chronically infected patients. However, the protective role of the sustained virologic response (SVR) achieved by second- and third-generation DAAs against the onset of hepatocellular carcinoma (HCC) and mortality is less well established

Short-term cardiac outcome in survivors of COVID-19: a systematic study after hospital discharge

Background: COVID-19 has caused considerable morbidity and mortality worldwide and cardiac involvement has been reported during infection. The short-term cardiac outcome in survivors of COVID-19 is not known. Objective: To examine the heart of patients who survived COVID-19 and to compare the cardiac outcome between patients who recovered from mild-to-moderate or severe illness. Methods: With use of ECG and echocardiography, we examined the heart of 105 patients who had been hospitalized with COVID-19 and were consecutively recruited after hospital discharge while attending follow-up visits. Survivors of COVID-19 were compared with 105 matched controls. We also compared the cardiac outcome and lung ultrasound scan between COVID-19 patients who had mild-to-moderate or severe illness. Results: Cardiac data were collected a median of 41\ua0days from the first detection of COVID-19. Symptoms were present in a low percentage of patients. In comparison with matched controls, no considerable structural or functional differences were observed in the heart of survivors of COVID-19. Lung ultrasound scan detected significantly greater residual pulmonary involvement in COVID-19 patients who had recovered from severe than mild-to-moderate illness. No significant differences were detected in ECG tracings nor were found in the left and right ventricular function of patients who had recovered from mild-to-moderate or severe illness. Conclusions: In a short-term follow-up, no abnormalities were identified in the heart of survivors of COVID-19, nor cardiac differences were detected between patients who had different severity of illness. With the limitations of a cross-sectional study, these findings suggest that patients who recover from COVID-19 do not have considerable cardiac sequelae. Graphic abstract: [Figure not available: see fulltext.

Unmatched ventilation and perfusion measured by electrical impedance tomography predicts the outcome of ARDS

Background In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions might reflect ARDS severity and affect the risk of ventilation-induced lung injury. Despite pathophysiological relevance, unmatched ventilation and perfusion are not routinely assessed at the bedside. The aims of this study were to quantify unmatched ventilation and perfusion at the bedside by electrical impedance tomography (EIT) investigating their association with mortality in patients with ARDS and to explore the effects of positive end-expiratory pressure (PEEP) on unmatched ventilation and perfusion in subgroups of patients with different ARDS severity based on PaO2/FiO2 and compliance. Methods Prospective observational study in 50 patients with mild (36%), moderate (46%), and severe (18%) ARDS under clinical ventilation settings. EIT was applied to measure the regional distribution of ventilation and perfusion using central venous bolus of saline 5% during end-inspiratory pause. We defined unmatched units as the percentage of only ventilated units plus the percentage of only perfused units. Results Percentage of unmatched units was significantly higher in non-survivors compared to survivors (32[27–47]% vs. 21[17–27]%, p < 0.001). Percentage of unmatched units was an independent predictor of mortality (OR 1.22, 95% CI 1.07–1.39, p = 0.004) with an area under the ROC curve of 0.88 (95% CI 0.79–0.97, p < 0.001). The percentage of ventilation to the ventral region of the lung was higher than the percentage of ventilation to the dorsal region (32 [27–38]% vs. 18 [13–21]%, p < 0.001), while the opposite was true for perfusion (28 [22–38]% vs. 36 [32–44]%, p < 0.001). Higher percentage of only perfused units was correlated with lower dorsal ventilation (r =  − 0.486, p < 0.001) and with lower PaO2/FiO2 ratio (r =  − 0.293, p = 0.039). Conclusions EIT allows bedside assessment of unmatched ventilation and perfusion in mechanically ventilated patients with ARDS. Measurement of unmatched units could identify patients at higher risk of death and could guide personalized treatment