278 research outputs found
Asymptomatic patients and immune subjects
No full textfirst_page settings Open AccessEntry Asymptomatic Patients and Immune Subjects by Sheila Veronese * [ORCID] and Andrea Sbarbati Department of Neurosciences, Biomedicine and Movement Sciences, Verona University, 10 Sq. L.A.Scuro, 37134 Verona, Italy * Author to whom correspondence should be addressed. Academic Editor: Stephen Bustin Encyclopedia 2022, 2(1), 109-126; https://doi.org/10.3390/encyclopedia2010008 Received: 15 November 2021 / Revised: 21 December 2021 / Accepted: 7 January 2022 / Published: 11 January 2022 (This article belongs to the Collection Encyclopedia of COVID-19) Download PDF Browse Figures Citation Export Definition An asymptomatic patient is someone who contracts a disease but shows no symptoms. An immune subject is a person who is free from virus infection. Both of these categories of people experience the limitations of government imposed by a pandemic situation, with one important difference. Probably only the first subjects contribute, in spite of themselves, to the spread of the disease and to the contagion of the people most susceptible to the virus. This implies that their detection is essential to limit infections. Therefore, knowing the characteristics of these people and those immune to the virus can be extremely useful in mitigating the effects of the disease and/or defeating it
Efficiency verification of a horizontal flow barrier via flowmeter tests and multilevel sampling
No full textThe remediation strategy for an industrial site located in a coastal area involves a pump and treat system and a horizontal flow barrier (HFB) penetrating the main aquifer. To validate the groundwater flow conceptual model and to verify the efficiency of the remediation systems, we carried out piezometric measurements, slug tests, pumping tests, flowmeter tests and multilevel sampling. Flowmeter tests are used to infer vertical groundwater flow directions, and base exchange index is used to infer horizontal flow directions at a metric scale. The selected wells are located both upstream and downstream of the HFB. The installation of the HFB produced constraints to the groundwater flow. A stagnant zone of contaminated freshwater floating over the salt wedge in the upper portion of the aquifer is detected downstream of the HFB. This study confirms that the adopted remediation system is efficiently working in the area upstream of the HFB and even downstream in the bottom part of the aquifer. At the same time, it has also confirmed that hot spots are still present in stagnant zones located downstream of the HFB in the upper part of the aquifer, requiring a different approach to accomplish remediation targets. The integrated approach for flow quantification used in this study allows to discriminate the direction and the magnitude of groundwater fluxes near an HFB in a coastal aquifer. Copyright (c) 2012 John Wiley & Sons, Ltd
The role of hydrogeological monitoring in a multidisciplinary context for the preservation of the critical zone in the natural reserve of Castelporziano Estate
No full textCritical Zone (CZ) science has developed in recent years, involving different disciplines that vary depending on the specific research focus. This multidisciplinary approach highlights the relevance of the Underground component of the Critical Zone (UCZ) in regulating the water cycle, which can influence the complex equilibrium of the whole CZ. In this study, we analyze evolution during the time of different parameters, characterizing the saturated and unsaturated parts of the UCZ of the Castelporziano Estate, a natural reserve located in a coastal area close to Rome. The purposes of these activities are to monitor the potential depletion of groundwater resources and understand the recharge mechanism processes characterizing the aquifer in the framework of occurring climate changes, net of anthropogenic pressure. The long-term analyses of water table variations carried out over the last 25 years, allowed us to preliminarily identify four different ranges of the slope coefficient of the water table, characterizing different areas of the Estate. Specifically, the Northern, Central, and Coastal areas have shown a general depletion trend in piezometric levels, while in the Eastern area, a positive trend has been recognized. Additional long-term analysis of piezometric level variations allowed us to confirm the presence of the four recharge areas and compare annual recharge and water table levels to assess the relationship between the saturated UCZ and meteoric recharge in the identified areas. To evaluate the role of the unsaturated UCZ in recharge mechanisms, the water content in the first meter of soil has also been analyzed, showing different responses of outcropping sediments in capturing rainfall during different periods of the year and under different rainfall input conditions, highlighting the pivotal role of rainfall for the Castelporziano UCZ, both for deep recharge of the water table and for feeding the forest roots. Stable isotopes confirm that Castelporziano UCZ feeding is strongly dependent on local meteoric recharge, also highlighting that evaporation processes are active in a limited way. The obtained results assess that the monitoring of UCZ has a crucial role in the correct preservation of more complex environmental systems, which include groundwater resources and the coastal Mediterranean forest
Morfologia ultrastrutturale delle cellule follicolo- stellate dell'adenoipofisi di ratto durante l'inibizione della lattazione
No full textSurfactant-like material on the chemoreceptorial surface of the frog's taste organ: an ultrastructural and electron spectroscopic imaging study
No full textTannic acid treatment was used to study the morphology of surfactant-like material (SLM) in the taste organ of Rana esculenta and the relation between this material and the cell types of the organ. On the surface of the taste organ SLM was associated with the apical processes of wing and putative taste cells. In SLM, a biphasic pattern was visible, a portion showed a lamellar periodicity (the repeating period of lamellae approximated 45 A), and a second portion showed an homogeneous electron density. Electron spectroscopic imaging revealed the presence of phosphorus and a large amount of calcium associated with the SLM. The result of our work suggests that SLM has a role in the perireceptorial events in the gustatory transduction by concentrating calcium in specific sites of the chemoreceptorial surface
The vomeronasal organ in the frog, Rana esculenta. An electron microscopy study
No full textThe ultrastructure of the vomeronasal organ (Jacobson's VNO) of the frog, Rana esculenta, was studied under the transmission and scanning electron microscope. Four cell types were identified: ciliated, bipolar, glial-like, and basal. Ciliated cells are unique to the frog VNO and show morphological evidence of secretion; bipolar (neuronal) cells are arranged in columns and reach the free surface of the epithelium with knobs bearing microvilli. The latter are in contact with amorphous material not described previously. Glial-like cells wrap bipolar cells in the epithelium and poorly differentiated basal cells are found just over the basal lamina. The vascular pump described in mammal VNO is not present at all in the frog VNO. We conclude that in the frog the VNO is closer to the reptilian than the mammalian VNO, although the frog VNO shows some unique morphological characteristics
Adipocyte morphology during hormone-induced lipid deposition and mobilization: an ultrastructural investigation in the perfused cardiac fat.
No full textThe rat pericoronary adipose tissue was perfused in the presence of either the liposynthetic hormone insulin or the lipolytic hormone noradrenaline. Insulin perfusion associated with a) larger adipocyte mean sectional diameter in comparison with noradrenaline perfusion; b) glycogen deposition; c) appearance of small fat globules at discrete sites at the periphery of the main lipid drop. The two latter phenomena were apparently dose-dependent. Massive lipid deposition was induced by addition of triglycerides to the perfusion medium and this associated with appearance of prominent endoplasmic reticulum in the cytoplasm. In noradrenaline-perfused adipose tissue many small lipid droplets surrounded the central lipid deposit and the endoplasmic reticulum was in the form of both thin long, dashed cisternae sometime surrounding lipid droplets and grouped, anastomosing tubular cisternae. The present work shows that the perfused white adipose tissue of the heart is a suitable model to study, in situ, the morphological effects of hormones in adipocytes. © 1995 Academic Press. All rights reserved
VALIDATION OF A DENSITY DEPENDENT GROUNDWATER TRANSPORT MODEL USING MASS RECOVERY RATE
No full textIn this short note is described the validation process of a density dependent groundwater transport model, previously implemented and published, using the mass recovery rate of dissolved Total Petroleum Hydrocarbons and Chloride from 67 pumping wells in a polluted site. A good fit between observed and calculated values was recorded, supporting the feasibility of flow and transport models validation in complex polluted sites where pump & treat remediation are applied and management strategies need to be rapid and robust
Ultrastructure of brown adipocytes mitochondria in cell culture from explants
No full textBrown adipocytes lose in culture their typical mitochondria, which are replaced by others of non typical morphology. During studies aimed at clarifying this phenomenon we found that better preservation of the 'typical' mitochondrial morphology is obtained in vitro after a long period of time, when cells from small fragments (explants) of brown adipose tissue (BAT) are cultured instead of collagenase-isolated brown adipocytes. These results suggest that the explant technique could be better suited to study brown adipocytes in culture than other methods employing collagenase-isolated cells
Assessing the effect of saltwater intrusion on petroleum hydrocarbons plumes via numerical modelling
No full textA contamination by petroleum hydrocarbons was detected in a sandy aquifer below a petrochemical plant in Southern Italy. The site is located near the coastline and bordered by canals which, together with pumping wells, control submarine groundwater discharge toward the sea and seawater intrusion (SWI) inland. In this study, a three-dimensional flow and transport model was developed using SEAWAT-4.0 to simulate the density-dependent groundwater flow system. Equivalent freshwater heads from 246 piezometers were employed to calibrate the flow simulation, while salinity in 193 piezometers was used to calibrate the conservative transport. A second dissolved species, total petroleum hydrocarbons (TPH), was included in the numerical model to simulate the plumes originating from light non-aqueous-phase liquid. A detailed field investigation was performed in order to determine the fate of dissolved hydrocarbons. Fifteen depth profiles obtained from multilevel samplers (MLS) were used to improve the conceptual model, originally built using a standard monitoring technique with integrated depth sampling (IDS) of salinity and TPH concentrations. The calibrated simulation emphasises that density-dependent flow has a great influence on the migration pattern of the hydrocarbons plume. This study confirms that calibration of density-dependent models in sites affected by SWI can be successfully reached only with MLS data, while standard IDS data can lead to misleading results. Thus, it is recommended to include MLS in the characterization protocols of contaminated sites affected by SWI, in order to properly manage environmental pollution problems of coastal zones. © 2012 Springer Science+Business Media B.V
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