864 research outputs found
Author Correction: Reliability of Total Grain-Size Distribution of Tephra Deposits (Scientific Reports, (2019), 9, 1, (10006), 10.1038/s41598-019-46125-8)
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper
Antimicrobial power of Cu/Zn mixed oxide nanoparticles to Escherichia coli
No full textThe antimicrobial power of a Cu/Zn mixed oxide was probed by viability study against E. coli. A facile, environment friendly synthesis of CuO, ZnO and Cu0.73Zn0.27O nanoparticles was carried out via hydroxycarbonate precursors and the samples characterized by several techniques. The antimicrobial efficacy of the nanoparticles was, then, probed by two independent growth inhibition essays, the culture methods and the optical density after 4 h, 8 h and 24 h contact time and shows both a time and concentration dependency. Remarkably the Cu0.73Zn0.27O mixed oxide exhibits the highest antimicrobial activity, with 90% growth inhibition already after 8 h for a dose of 200 μg/mL whereas CuO reaches the same performance only after 24 h and ZnO has, comparatively, only a limited activity
Reliability of Total Grain-Size Distribution of Tephra Deposits
No full textTotal Grain-Size Distribution (TGSD) of tephra deposits is key to the characterization of explosive volcanism, plume-dispersal modeling, and magmatic fragmentation studies. Nonetheless, various aspects that includes deposit exposure and data fitting make its determination extremely complex and affect its representativeness. In order to shed some lights on the reliability of derived TGSDs, we examine a large TGSD dataset in combination with a sensitivity analysis of sampling strategies. These analyses are based both on a well-studied tephra deposit and on synthetic deposits associated with a variety of initial eruptive and atmospheric conditions. Results demonstrate that TGSDs can be satisfactorily fitted by four distributions (lognormal, Rosin-Rammler, and power-law based either on the absolute or cumulative number of particles) that capture different distribution features. In particular, the Rosin-Rammler distribution best reproduces both the median and the tails of the TGSDs. The accuracy of reconstructed TGSDs is strongly controlled by the number and distribution of the sampling points. We conclude that TGSDs should be critically assessed based on dedicated sampling strategies and should be fitted by one of the mentioned theoretical distributions depending on the specific study objective (e.g., tephra-deposit characterization, physical description of explosive eruptions, tephra-dispersal modeling)
Corrigendum to “Assessing tephra total grain-size distribution: Insights from field data analysis” [Earth Planet. Sci. Lett. 443 (2016) 90–107] (S0012821X16300577)(10.1016/j.epsl.2016.02.040)
No full textThe authors found a mistake in the formulation of the distribution named Bi-Weibull distribution reported in the equation (A.2) of the Appendix A. The error affects equation (4) (which is the same as eq. (A.2)) and Table 4 in the original manuscript. In equation (A.2) the normalization constants were missing and there was an error in the argument of the exponent. The correct normalized distribution is:[formula fresented]. The corrected Table 4 and Fig. A.1 are reported below
Comparison of three different media for the detection of E. coli and coliforms in water.
No full textThe European Drinking Water Directive defines reference methods for the enumeration of microbiological parameters in drinking water. The method to be used for Escherichia coli and coliforms is the membrane filtration technique on Lactose TTC agar with Tergitol 7. Many technical drawbacks of the procedure, as well as its limitations regarding the recent taxonomy of coliforms, make it necessary to evaluate alternative methods. Two alternative assays, a chromogenic media (m-ColiBlu24®) and a defined substrate technology-DST test (Colilert 18/Quanty TrayTM) were compared with the ISO standard with attention to the phenotypic characteristic of the isolates. Results showed that the ISO method failed to detect an important percentage of coliforms and E. coli while m-ColiBlu24® and Colilert 18 provided results in a shorter time allowing the simultaneous detection of E. coli and coliforms with no further confirmation steps
Aspetti chimici e biologici delle acque e dei fanghi di risulta da un impianto di depurzione
No full text
Free fatty acid and glucose metabolism in human aging: evidence for operation of the Randle cycle
No full textWe assessed insulin effects on plasma free fatty acid (FFA) and glucose metabolism in seven elderly (71 +/- 2 yr) and in seven younger (21 +/- 1 yr) subjects matched for body weight and body mass index but not for percent body fat (32.4 +/- 3.8% in elderly vs. 20.4 +/- 3.5% in young, P < 0.05), by performing sequential euglycemic clamps at five insulin doses (0.6, 1.5, 3, 6, and 15
pmol.min-1.kg-1) in combination with indirect calorimetry and [1-14C]palmitate plus [3-3H]glucose infusion. At baseline, plasma FFA concentration, turnover infusion. At baseline, plasma FFA concentration, turnover and oxidation, and total lipid oxidation were all increased in the elderly (897 +/- 107 vs. 412 +/- 50 mumol/l and 11.2 +/- 1.4 vs. 5.14 +/- 0.86, 3.45 +/- 0.65 vs. 1.37 +/- 0.25,and 4.63 +/- 0.72 vs. 3.01 +/- 0.33 mumol.min-1.kg-1 lean body mass, P < 0.05 for all comparisons), whereas glucose turnover was similar as a result of decreased glucose oxidation (8.2 +/- 1.4 vs. 13 +/- 1.9 mumol.min-1.kg-1 lean body mass, P < 0.05) and increased glucose storage (6.6 +/- 1.4 vs. 1.7 +/- 1.3mmol.min-1.kg-1 lean body mass, P < 0.05). At all insulin infusions, plasma FFA concentration, turnover and oxidation, and total lipid oxidation were higher in the elderly than in the younger group (P < 0.05). However, if normalized per fat mass, all FFA and lipid metabolic fluxes, both in the postabsorptive state and during hyperinsulinemia, were comparable in the two groups
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