Ag/ZnO nanomaterials as high performance sensors for flammable and toxic gases

Ag/ZnO nanocomposites supported on polycrystalline Al2O3 were synthesized by an unprecedented approach combining plasma enhanced chemical vapor deposition (PE-CVD) of ZnO matrices and the subsequent deposition of Ag nanoparticles (NPs) by radio frequency (RF) sputtering. The system structure, composition and morphology were investigated by glancing incidence x-ray diffraction (GIXRD), secondary ion mass spectrometry (SIMS), field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDXS). A tailored dispersion and distribution of silver particles could be obtained under mild conditions by the sole variation of the sputtering time. Gas sensing properties toward flammable and toxic gases, both reducing (CH3CH2OH, CH3COCH3) and oxidizing (O3), were investigated in the temperature range 100-400?°C. Beside the high sensitivity, the developed sensors exhibited a response proportional to Ag content, thanks to catalytic and electronic effects promoted by silver NPs. In addition, discrimination between oxidizing and reducing analytes was enabled by a suitable choice of the adopted working temperature.     

Making Connections: Mesenchymal Stem Cells Manifold Ways to Interact with Neurons

Mesenchymal Stem Cells (MSCs) are adult multipotent cells able to increase sensory neuron survival: direct co-culture of MSCs with neurons is pivotal to observe a neuronal survival increase. Despite the identification of some mechanisms of action, little is known about how MSCs physically interact with neurons. The aim of this paper was to investigate and characterize the main mechanisms of interaction between MSCs and neurons. Morphological analysis showed the presence of gap junctions and tunneling nanotubes between MSCs and neurons only in direct co-cultures. Using a diffusible dye, we observed a flow from MSCs to neurons and further analysis demonstrated that MSCs donated mitochondria to neurons. Treatment of co-cultures with the gap junction blocker Carbenoxolone decreased neuronal survival, thus demonstrating the importance of gap junctions and, more in general, of cell communication for the MSC positive effect. We also investigated the role of extracellular vesicles; administration of direct co-cultures-derived vesicles was able to increase neuronal survival. In conclusion, our study demonstrates the presence and the importance of multiple routes of communication between MSCs and neurons. Such knowledge will allow a better understanding of the potential of MSCs and how to maximize their positive effect, with the final aim to provide the best protective treatment.     

Impact of contact data resolution on the evaluation of interventions in mathematical models of infectious diseases

Computational models offer a unique setting to test strategies to mitigate the spread of infectious diseases, providing useful insights to applied public health. To be actionable, models need to be informed by data, which can be available at different levels of detail. While high-resolution data describing contacts between individuals are increasingly available, data gathering remains challenging, especially during a health emergency. Many models thus use synthetic data or coarse information to evaluate intervention protocols. Here, we evaluate how the representation of contact data might affect the impact of various strategies in models, in the realm of COVID-19 transmission in educational and work contexts. Starting from high-resolution contact data, we use detailed to coarse data representations to inform a model of SARS-CoV-2 transmission and simulate different mitigation strategies. We find that coarse data representations estimate a lower risk of superspreading events. However, the rankings of protocols according to their efficiency or cost remain coherent across representations, ensuring the consistency of model findings to inform public health advice. Caution should be taken, however, on the quantitative estimations of those benefits and costs triggering the adoption of protocols, as these may depend on data representation.     

Cell and matrix morpho-functional analysis in chondrocyte micromasses

Micromass cultures represent a convenient means of studying chondrocyte physiology in the context of a tridimensional culture model. In this study, we present the first ultrastructural analysis of the distribution and organization of the extracellular components in micromasses in comparison with their cartilaginous counterparts. Primary chondrocytes obtained from osteoarthritis patients were pelleted in micromasses. Transmission electron microscopy and immunofluorescence were used to evaluate the distribution of major extracellular matrix proteins, i.e., aggrecan, chondroitin-4-sulfate, chondroitin-6-sulfate, and collagen I and II. Both approaches revealed a number of morphological features shared by micromass and cartilage chondrocytes. In particular, in micromasses, chondrocytes are in close contact with an organized extracellular matrix that adequately mimics that of cartilage. Cells were observed to establish specialized junctions for cell-extracellular matrix crosstalk. Noteworthy, cells seem endowed in a chondroitin sulfate-rich microenvironment, and thus possibly ensuring the immobilization of chemokines, a family of molecules emerging in osteoarthritis pathogenesis, in a haptotactic-like gradient to the chondrocytes, which facilitates the binding to their receptors. To determine the suitability of this model to investigate osteoarthritis pathogenesis, a potential apoptotic stimulus (endothelial IL-8) was used, and ultrastructural analysis assessed apoptosis induction. Micromass cultures were proved to be an experimental technique providing a large number of properly differentiated chondrocytes, and thus allowing reliable biochemical and morphological studies. They represent, therefore, a novel approach to osteoarthritis investigation that promises more thorough understanding of chondrocyte physiology in osteoarthritis.     

Occurence of potentially enterotoxigenic Bacillus cereus in infant milk powder

Considering that powdered infant milk formula effectively supports the growth of numerous pathogens, this study investigates the prevalence of potentially pathogenic Bacillus cereus in dried milk products by evaluating the occurrence of B. cereus and the presence of virulence-associated genes. The approach consisted of enriching, isolating and biochemical identifying isolates, followed by PCR assays aimed at the hbl (C, D, A, B), nhe (A, B, C) and cytK enterotoxin genes coding HBL complex, NHE complex and cytotoxin K, respectively. Among cytK-positive strains, the discrimination of two different forms for cytotoxin K, cytK-1 and cytK-2 was performed. Bacillus cereus was detected in powdered infant milk formula samples. All the strains harbored at least one gene of the cytK, HBL and NHE enterotoxins. Because of an increasing trend in invasive infections by B. cereus in infants and immunocompromised children, our PCR findings highlight the need to implement an adequate control plan in order to guarantee the health of potentially fragile consumers. From a hygiene point of view, intensive and continuous monitoring of potentially pathogenic B. cereus may be crucial for powdered infant milk formula safety and even recommended in order to assess the infant health risk, as proposed by Commission Regulation (EC) no. 1441/2007 on microbiological criteria for foodstuffs. Furthermore, the detection in this study of B. licheniformis, B. subtilis and B. mycoides strains raises significant health issues regarding Bacillus spp. in powdered infant milk formula.     

Potential of functional strains, isolated from traditional Maasai milk, as starters for the production of fermented milks

The purpose of this research was the evaluation of technological features and of the ability of functional LAB strains with desirable sensory characteristics, to produce fermented milk. Eight strains of Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus paracasei and Lactococcus lactis, isolated from Maasai traditional fermented milk in Kenya and previously tested for their probiotic properties, were selected for this investigation. Technological features such as growth kinetics in fresh heat-treated whole milk medium and survival in the final product during storage at 4 degrees C, were studied. The strains Lb. acidophilus BFE 6,059, Lb. paracasei BFE 5,264 and Lc. lactis BFE 6,049 showed the best potential and were thus selected for use as starter cultures in further trials with the objective to improve their technological performance and to optimise the sensory features of fermented milk obtained. The effects of fat (F), non-fat milk solids (S) and fermentation temperature (T), modulated according to a Central Composite Design, on fermentation rates and viability losses during refrigerated storage of the chosen starters, and on product texture parameters, were studied. From the data analysis, it was possible to select optimum conditions for enhancing positive sensory traits of final products and for improving the survival of these potentially probiotic cultures.     

Quantitative Systems Pharmacology and Biased Agonism at Opioid Receptors: A Potential Avenue for Improved Analgesics

Chronic pain is debilitating and represents a significant burden in terms of personal and socio-economic costs. Although opioid analgesics are widely used in chronic pain treatment, many patients report inadequate pain relief or relevant adverse effects, highlighting the need to develop analgesics with improved efficacy/safety. Multiple evidence suggests that G protein-dependent signaling triggers opioid-induced antinociception, whereas arrestin-mediated pathways are credited with modulating different opioid adverse effects, thus spurring extensive research for G protein-biased opioid agonists as analgesic candidates with improved pharmacology. Despite the increasing expectations of functional selectivity, translating G protein-biased opioid agonists into improved therapeutics is far from being fully achieved, due to the complex, multidimensional pharmacology of opioid receptors. The multifaceted network of signaling events and molecular processes underlying therapeutic and adverse effects induced by opioids is more complex than the mere dichotomy between G protein and arrestin and requires more comprehensive, integrated, network-centric approaches to be fully dissected. Quantitative Systems Pharmacology (QSP) models employing multidimensional assays associated with computational tools able to analyze large datasets may provide an intriguing approach to go beyond the greater complexity of opioid receptor pharmacology and the current limitations entailing the development of biased opioid agonists as improved analgesics.     

Fate of Antimony and Arsenic in Contaminated Waters at the Abandoned Su Suergiu Mine (Sardinia,Italy)

Mine Water and the Environment - We investigated the fate of Sb and As downstream of the abandoned Su Suergiu mine (Sardinia, Italy) and surrounding areas. The mined area is a priority in the...