Development of an Oral IgA Response against SARS-CoV-2 Following Immunization with Different COVID-19 Vaccines

The mucosal immune response is recognized to be important in the early control of infection sustained by viruses with mucosal tissues as the primary site of entry and replication, such as SARS-CoV-2. Mucosal IgA has been consistently reported in the mouth and eye of SARS-CoV-2 infected subjects, where it correlated inversely with COVID-19 symptom severity. Yet, there is still scarce information on the comparative ability of the diverse SARS-CoV-2 vaccines to induce local IgA responses at the virus entry site. Thus, the aim of this study was to assess the presence of anti-SARS-CoV-2 IgA in the saliva of 95 subjects vaccinated with a booster dose and different combinations of vaccines, including mRNA-1273 (Moderna), BNT162b2 (Pfizer-BioNTech), and Vaxzevria (AstraZeneca). The results showed the presence of a mucosal response in 93.7% of vaccinated subjects, with a mean IgA titer of 351.5 ± 31.77 U/mL, strongly correlating with the serum anti-SARS-CoV-2 IgG titer (p < 0.0001). No statistically significant differences emerged between the vaccine types, although the salivary IgA titer appeared slightly higher after receiving a booster dose of the mRNA-1273 vaccine (Moderna) following two doses of BNT162b2 (Pfizer-BioNTech), compared to the other vaccine combinations. These data confirm what was previously reported at the eye level and suggest that monitoring salivary IgA may be a useful tool for driving forward vaccine design and surveillance strategies, potentially leading to novel routes of vaccine administration and boosting

Megafloods in Europe can be anticipated from observations in hydrologically similar catchments

Megafloods that far exceed previously observed records often take citizens and experts by surprise, resulting in extremely severe damage and loss of life. Existing methods based on local and regional information rarely go beyond national borders and cannot predict these floods well because of limited data on megafloods, and because flood generation processes of extremes differ from those of smaller, more frequently observed events. Here we analyse river discharge observations from over 8,000 gauging stations across Europe and show that recent megafloods could have been anticipated from those previously observed in other places in Europe. Almost all observed megafloods (95.5%) fall within the envelope values estimated from previous floods in other similar places on the continent, implying that local surprises are not surprising at the continental scale. This holds also for older events, indicating that megafloods have not changed much in time relative to their spatial variability. The underlying concept of the study is that catchments with similar flood generation processes produce similar outliers. It is thus essential to transcend national boundaries and learn from other places across the continent to avoid surprises and save lives

Numerical and experimental methods for stream and wetland modelling

The general aim of my research was the development of innovative numerical and experimental methods for the study of water bodies, in particular wetlands and streams. The use of constructed wetlands (CWs) for waste water treatment is one technique that has shown potential to remove a variety of contaminants including municipal, agricultural, industrial wastewater and storm water. Also, for terrestrial environments and human activities is of primary importance to ensure quality and health safety of rivers and streams. Water quality degradation is mostly caused by the transport and transformation of solutes (pollutants) in rivers. The study of solute transport in wetlands and in rivers appears scientifically significant within a Doctoral Degree in Industrial Engineering since it is related to anthropogenic impacts mainly of industrial origin on the natural environment and on ecosystem services, in particular on surface water bodies and aquatic ecosystems. For these reasons, the improvements of both numerical and experimental methods used for understanding transport phenomena in transitional environments (rivers and wetlands) has a fundamental role for achieving better knowledge on the pollutants removal processes in such zones and thus better management and design of these water bodies. In Chapter 1 a short literature review is presented about: (i) hydrodynamics and removal performance modelling in constructed wetland systems, (ii) conservative and smart tracer techniques and (iii) solute transport modelling in rivers. Then the specific aims of my doctorate research are described. Chapter 2 presents the numerical modelling developed in COMSOL Multiphysics for the study of suspended sediment transport in vegetated wetlands, with different vegetation densities. The removal efficiencies were estimated and compared for the different vegetation densities and grain sizes. Chapter 3 presents the numerical modelling developed combining Telemac2D and Matlab codes for simulating hydrodynamics and solute transport in wetland with randomly generated bathymetries, but characterized by different statistical parameters determining different configurations of the bed forms. The removal efficiencies were then estimated and compared for the different bathymetries. Chapter 4 introduces first activities carried out on numerical and experimental methods for streams and executed with a classical approach at the retention processes study. The numerical model STIR was applied at several conservative tracer datasets, measured for the same reaches in different flow rate conditions. Classical retention parameters, such as diffusion coefficient, exchange rate, mean residence time, were calibrated and compared for the different flow rates. Chapter 5 focuses on the development and application of an innovative numerical tool for the study of reactive and smart tracers. The theoretical basis of STIR-RST software tool is described, in particular about the introduction of parameters representing decay and transformation of the smart tracer and about the chance of choosing if the 2 storage zones are arranged in-series or in-parallel with the main channel. Finally it is shown its application on a smart tracer field test case where Resazurin was used. Chapter 6 reports the experimental study developed for investigating the mass balance closure of the Resazurin-Resorufin (Raz-Rru) system at the cellular scale. In the designed laboratory experiments, the sorption and photodecay of the tracers were minimized and the use of different microbial communities allowed analysing recovery patterns independent of specific microbial species. For each test, total recovery (Raz + Rru) was monitored in the time for evaluating if tracer mass disappeared during the experiments for uptake by cells. A summary of main results and conclusions obtained in this 3-years research is given in Chapter 7. For an easier search of the bibliographic sources used in the text, references are given separately for each chapter and included at the end of the related chapter

Numerical and experimental methods for stream and wetland modelling

The general aim of my research was the development of innovative numerical and experimental methods for the study of water bodies, in particular wetlands and streams. The use of constructed wetlands (CWs) for waste water treatment is one technique that has shown potential to remove a variety of contaminants including municipal, agricultural, industrial wastewater and storm water. Also, for terrestrial environments and human activities is of primary importance to ensure quality and health safety of rivers and streams. Water quality degradation is mostly caused by the transport and transformation of solutes (pollutants) in rivers. The study of solute transport in wetlands and in rivers appears scientifically significant within a Doctoral Degree in Industrial Engineering since it is related to anthropogenic impacts mainly of industrial origin on the natural environment and on ecosystem services, in particular on surface water bodies and aquatic ecosystems. For these reasons, the improvements of both numerical and experimental methods used for understanding transport phenomena in transitional environments (rivers and wetlands) has a fundamental role for achieving better knowledge on the pollutants removal processes in such zones and thus better management and design of these water bodies. In Chapter 1 a short literature review is presented about: (i) hydrodynamics and removal performance modelling in constructed wetland systems, (ii) conservative and smart tracer techniques and (iii) solute transport modelling in rivers. Then the specific aims of my doctorate research are described. Chapter 2 presents the numerical modelling developed in COMSOL Multiphysics for the study of suspended sediment transport in vegetated wetlands, with different vegetation densities. The removal efficiencies were estimated and compared for the different vegetation densities and grain sizes. Chapter 3 presents the numerical modelling developed combining Telemac2D and Matlab codes for simulating hydrodynamics and solute transport in wetland with randomly generated bathymetries, but characterized by different statistical parameters determining different configurations of the bed forms. The removal efficiencies were then estimated and compared for the different bathymetries. Chapter 4 introduces first activities carried out on numerical and experimental methods for streams and executed with a classical approach at the retention processes study. The numerical model STIR was applied at several conservative tracer datasets, measured for the same reaches in different flow rate conditions. Classical retention parameters, such as diffusion coefficient, exchange rate, mean residence time, were calibrated and compared for the different flow rates. Chapter 5 focuses on the development and application of an innovative numerical tool for the study of reactive and smart tracers. The theoretical basis of STIR-RST software tool is described, in particular about the introduction of parameters representing decay and transformation of the smart tracer and about the chance of choosing if the 2 storage zones are arranged in-series or in-parallel with the main channel. Finally it is shown its application on a smart tracer field test case where Resazurin was used. Chapter 6 reports the experimental study developed for investigating the mass balance closure of the Resazurin-Resorufin (Raz-Rru) system at the cellular scale. In the designed laboratory experiments, the sorption and photodecay of the tracers were minimized and the use of different microbial communities allowed analysing recovery patterns independent of specific microbial species. For each test, total recovery (Raz + Rru) was monitored in the time for evaluating if tracer mass disappeared during the experiments for uptake by cells. A summary of main results and conclusions obtained in this 3-years research is given in Chapter 7. For an easier search of the bibliographic sources used in the text, references are given separately for each chapter and included at the end of the related chapter

Does the Mass Balance of the Reactive Tracers Resazurin and Resorufin Close at the Microbial Scale?

AbstractResazurin (Raz) is a phenoxazine dye that can be reduced irreversibly to the daughter compound resorufin (Rru) by aerobic respiration. Previous hydrologic studies using the Raz‐Rru reactive tracer system to quantify water‐sediment interactions and metabolic activity have reported that dilution‐corrected masses of Raz and Rru recovered are smaller than the mass of Raz injected. This lack of mass balance closure has been reported as a nonideality of this tracer system and, to date, it is still unclear what drives incomplete recovery. We used controlled laboratory experiments varying the initial concentrations of Raz, the duration of the experiments, and the type of microbial communities present to quantify mass balances of Raz and Rru under conditions that removed other suspected causes of incomplete recovery in field experiments, i.e., sorption to sediments and photodecay. We used the summation of Raz and Rru concentrations over time to assess mass recovery and variability and found mass recoveries in the range of 85.6–110.4%, with a maximum standard deviation of 7.5%. In three of the four experiments, no strong temporal trend in mass recovery is present. In an experiment with Bacillus subtilis bacteria, lower recovery and evidence of a temporal trend in recovery only occurred after 13 hr past the complete transformation of Raz (i.e., beyond the duration of most field experiments). These results suggest that the lack of mass recovery in field studies is likely associated with physical or chemical mechanisms rather than biological interactions with the Raz‐Rru tracer system

Design and implementation of “rainfall snacks”: new opportunity for conveying drops of science

Despite being a very common experience for most people, rainfall essentially remains a mystery for them. They unfortunately remain unaware of the underlying complexity of this geophysical field which exhibits extreme variability over wide ranges of scales in both space and time. In order to overcome this lack of knowledge and push people to pay more attention to rainfall and more generally their geophysical environment, we designed and implemented “rainfall snacks”. It basically consists of a snack designed as a small drop of science, in which each item conveys a simple take home message on rainfall. In order to fulfil the overall purpose, few basic principles are followed for each item / activity: 1) They have a clear and simple take home message on a given rainfall feature. 2) The studied feature is immediately visible at first sight, for example by systematic comparison between two situations to highlight the targeted feature very easily. 3) The snack somehow mimics or enables to visualise actual data, and a more scientific display of the corresponding data is prepared for discussion (pictures, graphs). When possible, we used data tailored to the target audience, i.e. coming from a place they know. 4) The activity is designed as a whole from an initial game to actively engage the audience to the tasting / savouring and the scientific explanation.Snacks with four different items were tested:Rainfall Drop Size Distribution variability with cookies (macaron / “baci di dama”) representing drops variability in shape and in the actual size in their fall. Rainfall monthly distribution and its variability, using glass with liquid (champagne, soda, water…) height corresponding to rainfall depth during a month Rainfall intermittency at various time scales using small cakes decorated with two different colours Spatial pattern of convective vs. stratiform event represented by fruits or cream coverage of tarts.  Each item has been tested in various contexts (family / friends meetings, lab meetings), and improved step by step. Presentation will describe in detail each “rainfall snack item”, and discuss the implementations and improvements.We found that people prefer a game approach, and this increases their active involvement and curiosity: they have to think more about the topic and to use their own reasoning, and this stimulates asking questions. The tasty food is a good motivation to participate (and to win the game). Although we did not really expect this at the beginning, it also sometimes enabled us to initiate a dialogue on what we did as researchers and as such bring research closer to the general public. In general, rainfall snacks enable us to communicate some science in a rather innovative, tasty and good looking way

How well does a convection-permitting regional climate model represent the reverse orographic effect of extreme hourly precipitation?

Estimating future short-duration extreme precipitation in mountainous regions is fundamental for risk management. High-resolution convection-permitting models (CPMs) represent the state of the art for these projections, as they resolve convective processes that are key to short-duration extremes. Recent observational studies reported a decrease in the intensity of extreme hourly precipitation with elevation. This "reverse orographic effect"could be related to processes which are subgrid even for CPMs. To quantify the reliability of future projections of extreme short-duration precipitation in mountainous regions, it is thus crucial to understand to what extent CPMs can reproduce this effect. Due to the computational demands however, CPM simulations are still too short for analyzing extremes using conventional methods. We use a non-asymptotic statistical approach (Simplified Metastatistical Extreme Value: SMEV) for the analysis of extremes from short time periods, such as the ones of CPM simulations. We analyze an ERA-Interim-driven Consortium for Small-Scale Modeling (COSMO-crCLIM, convection-resolving Climate Modelling) simulation (2000-2009; 2.2 km resolution), and we use hourly precipitation from 174 rain gauges in an orographically complex area in northeastern Italy as a benchmark. We investigate the ability of the model to simulate the orographic effect on short-duration precipitation extremes, as compared to observational data. We focus on extremes as high as the 20-year return levels. While overall good agreement is reported at daily and hourly duration, the CPM tends to increasingly overestimate hourly extremes with increasing elevation, implying that the reverse orographic effect is not fully captured. These findings suggest that CPM bias-correction approaches should account for orography. SMEV's capability of estimating reliable rare extremes from short periods promises further applications on short-time-period CPM projections and model ensembles.ISSN:1027-5606ISSN:1607-793

Ageing curtails the diversity and functionality of nascent CD8 + T cell responses against SARS-CoV-2

Age-related changes in the immune system are thought to underlie the vulnerability of elderly individuals to emerging viral diseases, such as coronavirus disease 2019 (COVID-19). In this study, we used a fully validated in vitro approach to determine how age impacts the generation of de novo CD8+ T cell responses against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19. Our data revealed a generalized deficit in the ability of elderly individuals to prime the differentiation of naïve precursors into effector CD8+ T cells defined by the expression of interferon (IFN)-γ and the transcription factor T-bet. As a consequence, there was an age-related decline in the diversity of newly generated CD8+ T cell responses targeting a range of typically immunodominant epitopes derived from SARS-CoV-2, accompanied by an overall reduction in the expression frequency of IFN-γ. These findings have potential implications for the development of new strategies to protect the elderly against COVID-19