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62.
Valerio F De Bellis P Lonigro SL Visconti A Lavermicocca P 《International journal of food microbiology》2008,122(3):328-332
Four fermentation products (FPs) of the lactic acid bacterium Lactobacillus plantarum ITM21B were screened for their anti-Bacillus activity in vitro and in bread-making trials. Results of the storage tests performed with loaves prepared with an FP or calcium propionate demonstrated that after 3 days at 30 degrees C, gross spoilage was evident in only the control loaves, which contained Bacillus subtilis at numbers of about 10(9) cfu/g. The highest inhibitory activity was shown by DM-FP obtained by growing L. plantarum in a defined medium (DM). Significantly, this medium contained an amino acceptor of the aminoacid transamination, namely alpha-ketoglutaric acid, and an aminoacid pool. With loaves prepared using the DM-acid mixture which simulated the DM-FP composition, the same reduction of ropy spoilage as with DM-FP was obtained after 3 days, while the efficacy of the mixture decreased after 7 days. This result suggests the potential involvement of some unknown metabolites in the inhibitory activity of DM-FP. In baked products made with flour based media (M1-FP, M2-FP, M3-FP), no ropy symptoms were noticeable after 3 days storage although a considerable Bacillus count was detected. DM-FP was as effective as calcium propionate (0.3% w/w, based on flour mass) in prolonging the Bacillus free-shelf life of yeast-leavened bread for 7 days. 相似文献
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María C. Ruiz Iván González Valerio Rodriguez Rafael Padilla 《Mineral Processing and Extractive Metallurgy Review》2021,42(1):1-8
ABSTRACT The effect of chloride ions on the copper extraction equilibria, the rate of extraction, copper/iron selectivity, and chloride extraction was studied for organic phases containing pure ketoxime (LIX 84-IC) and pure nonylaldoxime (LIX 860N-IC). In these systems, the used aqueous phase contained total chloride concentrations from 0 to 110 g/l. It was determined that the chloride ions in the aqueous solution had a large negative effect on the extraction equilibria for LIX 84-IC and a small effect for LIX 860N-IC. This deleterious effect is attributed to an increase in the hydrogen ion activity coefficient in the presence of chloride ions. The chloride accelerated the rate of copper extraction even though the reaction was fast in all the tested conditions. An increase in the temperature from 25°C to 35°C affected positively the extraction equilibria for LIX 84-IC. 相似文献
65.
Abhinav Anand Matteo L. Zaffalon Graziella Gariano Andrea Camellini Marina Gandini Rosaria Brescia Chiara Capitani Francesco Bruni Valerio Pinchetti Margherita Zavelani‐Rossi Francesco Meinardi Scott A. Crooker Sergio Brovelli 《Advanced functional materials》2020,30(4)
Ternary I‐III‐VI2 nanocrystals (NCs), such as CuInS2, are receiving attention as heavy‐metals‐free materials for solar cells, luminescent solar concentrators (LSCs), LEDs, and bio‐imaging. The origin of the optical properties of CuInS2 NCs are however not fully understood. A recent theoretical model suggests that their characteristic Stokes‐shifted and long‐lived luminescence arises from the structure of the valence band (VB) and predicts distinctive optical behaviours in defect‐free NCs: the quadratic dependence of the radiative decay rate and the Stokes shift on the NC radius. If confirmed, this would have crucial implications for LSCs as the solar spectral coverage ensured by low‐bandgap NCs would be accompanied by increased re‐absorption losses. Here, by studying stoichiometric CuInS2 NCs, it is revealed for the first time the spectroscopic signatures predicted for the free band‐edge exciton, thus supporting the VB‐structure model. At very low temperatures, the NCs also show dark‐state emission likely originating from enhanced electron‐hole spin interaction. The impact of the observed optical behaviours on LSCs is evaluated by Monte Carlo ray‐tracing simulations. Based on the emerging device design guidelines, optical‐grade large‐area (30×30 cm2) LSCs with optical power efficiency (OPE) as high as 6.8% are fabricated, corresponding to the highest value reported to date for large‐area devices. 相似文献
66.
M. Di Giulio V. Di Valerio D. Bosco E. Marsich A. Cataldi L. Cellini S. Sancilio 《Journal of materials science. Materials in medicine》2018,29(4):36
The molecular mechanisms leading to Streptococcus mitis capability of entering oral cells were investigated in a co-culture of S. mitis and Human Gingival Fibroblasts (HGFs) in the presence of saliva. An innovative colloidal solution based on silver nanoparticles (Chitlac-nAg), a promising device for daily oral care, was added to the experimental system in order to study the effects of silver on the bacterial overgrowth and ability to enter non-phagocytic eukaryotic cells. The entry of bacteria into the eukaryotic cells is mediated by a signalling pathway involving FAK, integrin β1, and the two cytoskeleton proteins vinculin and F-actin, and down-regulated by the presence of saliva both at 3 and 48?h of culture, whereas Chitlac-n Ag exposure seems to influence, by incrementing it, the number of bacteria entering the fibroblasts only at 48?h. The formation of fibrillary extrusion from HGFs and the co-localization of bacteria and silver nanoparticles within the fibroblast vacuoles were also recorded. After longer experimental times (72 and 96?h), the number of S. mitis chains inside gingival cells is reduced, mainly in presence of saliva. The results suggest an escape of bacteria from fibroblasts to restore the microbial balance of the oral cavity. 相似文献
67.
Frontoni Emanuele Mancini Adriano Zingaretti Primo Contigiani Marco Bello Luigi Di Placidi Valerio 《Microsystem Technologies》2018,24(3):1369-1377
Microsystem Technologies - The shelf out-of-stock (SOOS) problem is relevant for retailers and producers since the absence of products on the shelf can lead to a significant reduction of... 相似文献
68.
Simonetta Tuti Franco Pepe Daniela Pietrogiacomi Valerio Indovina 《Catalysis Today》2002,75(1-4):373-378
FeOx/ZrO2 samples, prepared by impregnation with Fe(NO3)3, were characterised by means of DRS, XRD, FTIR, redox cycles and volumetric CO adsorption. Volumetric CO adsorption, combined with FTIR, showed that 45% of iron in the sample containing 2.8 Fe atoms nm−2 was capable of forming iron carbonyls. DRS evidenced Fe2O3 on samples with Fe-content≥2.8 atoms nm−2. The selective catalytic reduction of NO with C3H6 in the presence of O2 was studied with a reactant mixture containing NO=4000 ppm, C3H6=4000 ppm, O2=2%. The dependence on iron-content suggests that only isolated iron, prevailing in dilute FeOx/ZrO2, is active for NO reduction, whereas iron on the surface of small oxide particles, prevailing in concentrated FeOx/ZrO2, is active for C3H6 combustion. 相似文献
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70.
During medium and high intensity storm events, urban drainage networks can rapidly reach their maximum capacity, and subsequently floods can occur. Owing to the non-linearity of the processes involved, it is evident that the return period of a rainfall is different from the return period of the generated overflows. Therefore, the assessment of the maximum overflow volume related to a given return period is a key element in the management of urban drainage networks, since it may cause problems to infrastructure and economic losses. In this paper, a combined methodology for the hydraulic rehabilitation of such networks is proposed, by expressing their hydraulic critical conditions in terms of overflow volumes rather than rainfall volumes and considering both observed rainfall data and synthetic hyetographs derived from statistical analysis. The first application of the proposed methodology to the sewer network of the Mesola Municipality is presented and commented on. 相似文献