143 research outputs found

    Analyses of odours from concentrated animal feeding operations: a review

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    Concentrated Animal Feeding Operations (CAFOs) are widely present all over the world due to the high population demand for food and products of animal origin. However, they have generated several environmental concerns, including odour nuisance, which affects people health and quality of life. Odours from livestock are a very complex mixtures of molecules and their analytical investigation is highly demanding. Many works have been published regarding the study of odours from CAFOs, using different techniques and technologies to face the issue. Thus, the aim of this review paper is to summarize all the ways to study odours from CAFOs, starting from the sampling methods and then treating in general the principles of Dynamic Olfactometry, Gas Chromatography coupled with Mass Spectrometry and Electronic Noses. Finally, a deep literature summary of Gas Chromatography coupled with Mass Spectrometry and Electronic Noses applied to odours coming from poultry, dairy and swine feeding operations is reported. This work aims to make some order in this field and it wants to help future researchers to deal with this environmental problem, constituting a state-of-the-art in this field

    Efficiency of an Air Cleaner Device in Reducing Aerosol Particulate Matter (PM) in Indoor Environments

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    Abstract: Indoor air quality (IAQ) in household environments is mandatory since people spend most of their time in indoor environments. In order to guarantee a healthy environment, air purification devices are often employed. In the present work, a commercial household vacuum cleaner has been tested in order to verify its eciency in reducing the mass concentration and particle number of aerosol particulate matter (PM). The eciency has been tested measuring, while the instrument was working, PM10 (particles with aerodynamic diameter less than 10 m), PM2.5 (particles with aerodynamic diameter less than 2.5 m), PM1 (particles with aerodynamic diameter less than 1 m), and 7 size-fractions in the range between 0.3 and >10 m. Measurements have been carried out by means of a portable optical particle counter instrument and simulating the working conditions typical of a household environment. It has been found that the tested commercial device significantly reduces both PM concentrations and particle number, especially in the finest fraction, i.e., particles in the range 0.3\u20130.5 m, allowing an improvement of indoor air quality

    TiO2 Nanocrystals Decorated CVD Graphene for Electroanalytical Sensing

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    In this work, the manufacturing and characterization of an optically transparent and UV-light photoactive anode, formed of monolayer graphene grown by chemical vapor deposition (CVD) and decorated with a close packed multilayered nanostructured layout of colloidal TiO2 nanocrystals (NCs), are reported. The hybrid material has been prepared by a facile solution-based procedure, which relays on soaking the CVD graphene in a solution of 1-pyrene butyric acid (PBA) surface coated TiO2 NCs, achieved upon implementation of a capping exchange process for displacing the pristine organic ligand deriving from the colloidal synthesis. Pyrene undergoes \u3c0-\u3c0 stacking interactions, anchoring the NCs to the platform with retention of the NC geometry and composition. The NCs immobilize onto the graphene platform with preservation of its aromatic structure and the resulting hybrid has been found optically transparent in the visible spectral range. (Photo)electrochemical investigation shows that the composite material has a promising sensitivity for selectively detecting dopamine and norepinephrine and, concomitantly, exhibits a (photo)electric activity higher than that of bare graphene. Thus, the achieved hybrid material results interesting for the manufacturing of photo-active components to integrate in photo-renewable sensor elements along with photodetectors and solar cells

    Functional Hybrids of Multilayer CVD Graphene and Colloidal Anatase Nanocrystals

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    UV-light photoactive hybrids based on CVD graphene (from 1 to 5 layers) decorated with TiO2 nanocrystals (NC) surface functionalized with 1-pyrene butyric acid (PBA), were prepared by a simple solution-based procedure. PBA functionalization was obtained by a capping exchange procedure onto pre-synthesized organic-capped NCs [1]. An in-depth physico-chemical characterization demonstrated the successful immobilization of the colloidal NCs on the graphene multilayers, which preserves or even enhances the graphene intrinsic structural properties: the electrical conductivity is higher than that measured for bare graphene, due to a p-doping effect, related to a hole transfer from the nano-objects to graphene, mediated by the short aromatic ligand acting as a charge channel. The hybrids properties are strongly dependent on the number of layers of CVD graphene. The use of two redox probes [inner-sphere, surface sensitive (K4Fe(CN)6) and outer-sphere, surface insensitive (Ru(NH3)6Cl3)], in a CV and EIS study, allowed to understand these features, showing a strong difference between the mono-, the bi- and the other multi-layers, in terms of different diffusional mechanism and redox active sites [2]. Moreover, the stacked layers of the pyrene-coated TiO2 NCs are found to increase the electroactivity, the capacitive behavior, as well as the photo-electrical response of graphene, concomitantly maintaining its high charge mobility. The photoelectrical conversion of the hybrid is enhanced of 50% with respect to the bare graphene, with a long recombination lifetime of the photogenerated electron-hole pairs. For all the above reasons, the photoactive composite has a great potential as an optically transparent component for manufacturing photoanodes to be integrated in solar cells or photodetectors and in FETs or (photo)electrochemical sensors, also exploiting the possibility of photorenovating the sensor surface [3]. [1] C. Ingrosso et al., ACS Appl. Mater. & Interfaces 7 (2015) 4151-4159. [2] D.A. Brownson, D.K. Kampouris, C.E. Banks, Chem. Soc. Rev. 41 (2012) 6944-6976. [3] V. Pifferi et al., Anal. Bioanal. Chem. 408(26) (2016), 7339-7349

    Gene and protein expression in response to different growth temperatures and oxygen availability in Burkholderia thailandensis.

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    Published onlineJournal ArticleResearch Support, Non-U.S. Gov'tThis is the final version of the article. Available from Public Library of Science via the DOI in this record.Burkholderia thailandensis, although normally avirulent for mammals, can infect macrophages in vitro and has occasionally been reported to cause pneumonia in humans. It is therefore used as a model organism for the human pathogen B. pseudomallei, to which it is closely related phylogenetically. We characterized the B. thailandensis clinical isolate CDC2721121 (BtCDC272) at the genome level and studied its response to environmental cues associated with human host colonization, namely, temperature and oxygen limitation. Effects of the different growth conditions on BtCDC272 were studied through whole genome transcription studies and analysis of proteins associated with the bacterial cell surface. We found that growth at 37°C, compared to 28°C, negatively affected cell motility and flagella production through a mechanism involving regulation of the flagellin-encoding fliC gene at the mRNA stability level. Growth in oxygen-limiting conditions, in contrast, stimulated various processes linked to virulence, such as lipopolysaccharide production and expression of genes encoding protein secretion systems. Consistent with these observations, BtCDC272 grown in oxygen limitation was more resistant to phagocytosis and strongly induced the production of inflammatory cytokines from murine macrophages. Our results suggest that, while temperature sensing is important for regulation of B. thailandensis cell motility, oxygen limitation has a deeper impact on its physiology and constitutes a crucial environmental signal for the production of virulence factors.This work was supported by Fondazione CARIPLO (Progetto Vaccini, contract number 2009–3577) and by Ministero dell’Istruzione, dell’Università e della Ricerca (MIUR) (project FIRB RBLA039LSF). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Novel N^C^N-cyclometallated platinum complexes with acetylide co-ligands as efficient phosphors for OLEDs

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    Two new cyclometallated platinum(ii) complexes have been prepared that incorporate a terdentate N^C^N-coordinating ligand and a monodentate acetylide co-ligand. The complexes, namely [PtL 3-CC-C 6H 3F 2] and [PtL 6-CC-C 6H 3F 2] (where HL 3 = 5-methyl-1,3-di(2-pyridyl) benzene; HL 6 = 5-mesityl-1,3-di(2-pyridyl)benzene; H-CC-C 6H 3F 2 = 3,5-difluorophenylacetylene), were prepared by ligand metathesis from the corresponding chloro complex PtL nCl. Both of the new complexes are intensely luminescent in solution, displaying quantum yields superior to PtL nCl. OLEDs have been prepared using the new compounds as phosphorescent emitters. Although both lead to efficient devices, the best electroluminescence quantum efficiencies are obtained with the derivative of HL 6, having the mesityl group on the cyclometallated phenyl ring. The superior performance with this complex can be rationalised in terms of the greater steric hindrance that serves to reduce aggregate-induced quenching

    Enhanced photoactivity and conductivity in transparent TiO2 nanocrystals/graphene hybrid anodes

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    An optically transparent and UV-light active anode, characterized by high (photo) conductivity, charge mobility and exciton lifetime, based on graphene, grown by CVD, decorated with colloidal TiO2 nanocrystals (NCs), has been fabricated, by a direct and facile solution-based procedure. TiO2 NCs anchor onto graphene by means of p-p stacking interactions occurring between the pyrene-1-butyric acid (PBA) surface coating ligand and the 2-D platform and assemble in a highly interconnected multilayered layout, by means of interligand pi-pi forces, retaining composition and geometry, along with the graphene structure. Remarkably, the PBA-coated TiO2 NCs on the graphene increase its electrical conductivity, electroactivity, and capacitive behavior, as well as photoelectrical response under UV-light, resulting in a 50% enhanced photoelectroactivity and a long exciton recombination lifetime. The photoanodes can be integrated into solar cells as optically transparent electrodes, in photodetectors, FETs and (bio)sensors

    3D Mass Spectrometry Imaging Reveals a Very Heterogeneous Drug Distribution in Tumors

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    Mass Spectrometry Imaging (MSI) is a widespread technique used to qualitatively describe in two dimensions the distribution of endogenous or exogenous compounds within tissue sections. Absolute quantification of drugs using MSI is a recent challenge that just in the last years has started to be addressed. Starting from a two dimensional MSI protocol, we developed a three-dimensional pipeline to study drug penetration in tumors and to develop a new drug quantification method by MALDI MSI. Paclitaxel distribution and concentration in different tumors were measured in a 3D model of Malignant Pleural Mesothelioma (MPM), which is known to be a very heterogeneous neoplasm, highly resistant to different drugs. The 3D computational reconstruction allows an accurate description of tumor PTX penetration, adding information about the heterogeneity of tumor drug distribution due to the complex microenvironment. The use of an internal standard, homogenously sprayed on tissue slices, ensures quantitative results that are similar to those obtained using HPLC. The 3D model gives important information about the drug concentration in different tumor sub-volumes and shows that the great part of each tumor is not reached by the drug, suggesting the concept of pseudo-resistance as a further explanation for ineffective therapies and tumors relapse

    TiO2 Nanocrystals Decorated CVD Graphene based Hybrid for UV-light Active Photoanode

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    n this work, the manufacturing and characterization of an optically transparent and UV-light photoactive anode, formed of graphene grown by chemical vapor deposition (CVD) decorated with a close packed multilayer nanostructured layout of colloidal TiO2 nanocrystals (NCs), has been reported. The hybrid material was prepared by a facile solution-based procedure, which relays on incubating the CVD graphene in a solution of 1-pyrene butyric acid (PBA)-surface coated TiO2 NCs. Pyrene undergoes pi-pi stacking interactions, anchoring the NCs to the graphene platform with retention of the NC geometry and composition. Concomitantly, the NCs immobilize onto graphene preserving the structure of the aromatic platform. Photoelectrochemical investigation shows that the composite material exhibits a photoelectric response 50% higher than that of bare graphene based electrodes

    3D Mass Spectrometry Imaging Reveals a Very Heterogeneous Drug Distribution in Tumors

    Get PDF
    Mass Spectrometry Imaging (MSI) is a widespread technique used to qualitatively describe in two dimensions the distribution of endogenous or exogenous compounds within tissue sections. Absolute quantification of drugs using MSI is a recent challenge that just in the last years has started to be addressed. Starting from a two dimensional MSI protocol, we developed a three-dimensional pipeline to study drug penetration in tumors and to develop a new drug quantification method by MALDI MSI. Paclitaxel distribution and concentration in different tumors were measured in a 3D model of Malignant Pleural Mesothelioma (MPM), which is known to be a very heterogeneous neoplasm, highly resistant to different drugs. The 3D computational reconstruction allows an accurate description of tumor PTX penetration, adding information about the heterogeneity of tumor drug distribution due to the complex microenvironment. The use of an internal standard, homogenously sprayed on tissue slices, ensures quantitative results that are similar to those obtained using HPLC. The 3D model gives important information about the drug concentration in different tumor sub-volumes and shows that the great part of each tumor is not reached by the drug, suggesting the concept of pseudo-resistance as a further explanation for ineffective therapies and tumors relapse
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