1,721,051 research outputs found
Silver nanoparticles in polymeric matrices for fresh food packaging
Full text linkThe growing demand for increased fresh food shelf life as well as the need of protection
against foodborne diseases urged the development of antimicrobial food packaging. Among the
most efficient methods, the combination of organic–inorganic, packaging, i.e. polymer embedded
metal nanoparticles proved to be highly effective. Silver nanoparticles (AgNPs), in particular, have
antimicrobial, anti-fungi, anti-yeasts and anti-viral activities and can be combined with both nondegradable and edible polymers for active food packaging. The actual application of AgNPs in food
packaging is regulated by EU and USA food safety authorities in a prudent way, due to the inability
to make conclusive statements on their toxicity. Therefore, their use is evaluated in terms of Ag+
migration into the packed food.
In this mini review, the most recent studies are reported on protection of meat, fruit and dairy
products against the most common food pathogens by AgNPs-doped non-degradable and edible
polymers and oils are reported
Novel Synthesis of Zinc Oxide Nanoparticles from Type IV Deep Eutectic Solvents
Full text linkOne of the fields where DES show remarkable added-values is the synthesis of inorganic materials, in particular nanoparticles. In this field, the inherent and highly-tunable nano-homogeneities of DES structure give origin to a marked templating effect, a precious role that has led to the recent bloom of a vast number of studies exploiting these new synthesis media to prepare nanomaterials and composite structures of various kinds. In this contribution, three examples of synthesis of nanoparticles containing zinc, using metal type-IV Deep Eutectic Solvents, a pathway that has never been explored so far, is described. The prepared materials have layered shapes, and when zinc nitrate is used as DES component, pure layered ZnO is obtained, forming nanometric platelets that assemble to form flower-like aggregates. The prepared nanoparticles show intrinsic fluorescence, and are being further studied to set up sensors for the detection of various contaminants
Recent Advances in the Synthesis of Inorganic Materials Using Environmentally Friendly Media
Full text linkDeep Eutectic Solvents have gained a lot of attention in the last few years because of their vast applicability in a large number of technological processes, the simplicity of their preparation and their high biocompatibility and harmlessness. One of the fields where DES prove to be particularly valuable is the synthesis and modification of inorganic materials—in particular, nanoparticles. In this field, the inherent structural inhomogeneity of DES results in a marked templating effect, which has led to an increasing number of studies focusing on exploiting these new reaction media to prepare nanomaterials. This review aims to provide a summary of the numerous and most recent achievements made in this area, reporting several examples of the newest mixtures obtained by mixing molecules originating from natural feedstocks, as well as linking them to the more consolidated methods that use “classical” DES, such as relin
Contamination Microbiologique de l’environnement. Méthodes de détection des bactériophages
No full textL’igienista: controllo dell’acqua potabile, depurazione osmotica, livello minimo di filtraggio batteriologico, controllo dell’ambiente e dei percorsi.
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Green zinc/galactomannan-based hydrogels push up the photovoltage of quasi solid aqueous dye sensitized solar cells
Full text linkIn the present work, we implement environmentally friendly water-based quasi-solid electrolytes (QSE) for dye sensitized solar cells (DSSCs), displaying an unprecedent open circuit voltage (VOC) as high as 750 mV. the production of the hydrogel for QSE-DSSCs is achieved by exploiting the concept of fully green design and fabrication, through the selection of components such as the natural polysaccharide galactomannan (GM), biocompatible zinc salts, and the employment of eco-friendly synthetic procedures to produce the hybrid gelating agents. In the process, moderate temperature (<40 °C), only aqueous solutions are employed, and, at most, ethanol is used in some phases of the procedure. depending on the type of the initial salt, either zinc hydroxysulfate lamellae or zinc oxide nanoparticles are created within the gel matrix, with a more extended nanoporous structure in the latter case. the nanostructures and the gels are investigated by multiple techniques, including X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Upon ensuing addition of I-/I3- redox mediator and assembling of the device, state-of-the-art aqueous QSE-DSSCs are achieved. The latter couples a 2 % efficiency (limited by charge diffusion as proved by electrochemical Impedance spectroscopy) with a good average visible transmittance (AVT), and light utilization efficiency (LUE), a couple of coveted features in wave-selective or semi-transparent devices. finally, linear response-time dependent DFT (LR-TDDFT) simulations are carried out on a model iodine/iodide layered zinc hydroxy sulphate structure towards a better understanding of the mechanism responsible for the high AVT
Problematiche connesse con l'applicazione della RT-PCR real-time nelle analisi ambientali.
No full textMolecular biology techniques allow high sensitivity and specificity in the detection of enteric viruses in various environmental samples, and are considerably less costly and more rapid than traditional analytical methods. Real time RT-PCR technology allows accurate, efficient, and reproducible quantification of viral genes, by amplifying enteroviral RNA directly from an adequately treated environmental sample. It uses different chemical systems, including TaqMan and Syber Green probes, for detection of the amplificon. Both systems allow quantification of the initial number of copies in each cycle by comparing values with those of an external calibration curve (standard curve), generated by serial dilutions of a reference RNA sample with a known concentration. Difficulties in generating a standard curve for each enteric virus however, make standardization of the system time consuming. In an attempt to overcome this obstacle, we used an internal standard with a known concentration, to obtain a valid calibration curve for the quantification of environmental enteroviruses. A comparative analysis was performed with various commercially available extraction and amplification systems to evaluate the method's efficiency and reproducibility
Problematiche connesse con l'applicazione della RT-PCR Real-Tima nelle analisi ambientali.
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