52 research outputs found

    Crystal growth of NdNiO3 perovskite under high oxygen pressure

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    Well-shaped single crystals of NdNiO3 perovskite have been grown for the first time under high oxygen pressure conditions, in a belt-type press at 4 GPa..

    Pulsed pressure treatment for inactivation of Escherichia coli and Listeria innocua in whole milk

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    E. coli and L. innocua in whole milk were subjected to continuous pressure treatments (300, 350, 400, 450, 500, 550 and 600 MPa) at ambient temperature for 5, 10, 15 and 20 min. These treatments underlined that at moderate pressure values (300, 350 and 400 MPa), increasing the pressurization time from 5 to 20 min did not improve cell death to a great extent. Therefore, pulsed pressure treatments (at 300, 350 and 400 MPa) for 5 min (2.5 min Ă— 2 pulses, 1 min Ă— 5 pulses and 0.5 min Ă— 10 pulses), 10 min (5 min Ă— 2 pulses, 2 min Ă— 5 pulses and 1 min Ă— 10 pulses), 15 min (5 min Ă— 3 pulses, 3 min Ă— 5 pulses and 1.5 min Ă— 10 pulses) and 20 min (10 min Ă— 2 pulses, 5 min Ă— 4 pulses, 4 min Ă— 5 pulses and 2 min Ă— 10 pulses) were applied. As already observed in continuous pressure experiments, in pulsed pressure treatments the inactivation level is improved with increasing pressure level and in addition with the number of applied pulses; however, the effect of pulse number is not additive. Results obtained in this study indicated that pulsed pressure treatments could be used to pasteurize the whole milk at lower pressure values than the continuous pressure treatments. Nevertheless, an optimization appears definetely necessary between the number of pulses and pressure levels to reach the desirable number of log-reduction of microorganisms

    Inactivation of Staphylococcus aureus and Salmonella enteriditis in tryptic soy broth and caviar samples by high pressure processing

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    We studied the action of high pressure processing on the inactivation of two foodborne pathogens, Staphylococcus aureus ATCC 6538 and Salmonella enteritidis ATCC 13076, suspended in a culture medium and inoculated into caviar samples. The baroresistance of the two pathogens in a tryptic soy broth suspension at a concentration of 108-109 colony-forming units/ml was tested for continuous and cycled pressurization in the 150- to 550-MPa range and for 15-min treatments at room temperature. The increase of cycle number permitted the reduction of the pressure level able to totally inactivate both microorganisms in the tryptic soy broth suspension, whereas the effect of different procedure times on complete inactivation of the microorganisms inoculated into caviar was similar

    Inactivation of Staphylococcus aureus and Salmonella enteriditis in tryptic soy broth and caviar samples by high pressure processing

    No full text
    We studied the action of high pressure processing on the inactivation of two foodborne pathogens, Staphylococcus aureus ATCC 6538 and Salmonella enteritidis ATCC 13076, suspended in a culture medium and inoculated into caviar samples. The baroresistance of the two pathogens in a tryptic soy broth suspension at a concentration of 108-109 colony-forming units/ml was tested for continuous and cycled pressurization in the 150- to 550-MPa range and for 15-min treatments at room temperature. The increase of cycle number permitted the reduction of the pressure level able to totally inactivate both microorganisms in the tryptic soy broth suspension, whereas the effect of different procedure times on complete inactivation of the microorganisms inoculated into caviar was similar

    Stabilization of caviar by high pressure.

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    International Congress, Technological Innovation and Enhancement of Marginal Products, Faculty of Agricultural Science, Foggia 2005

    Crystal structure of NdNiO3 at 123 and 292 K.

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    Well-shaped, small single crystals of the NdNiO3 perovskite were grown under high oxygen pressure conditions in a belt-type press at 4 GPa. The reaction took place in sealed platinum capsules in the presence of KClO3 as oxidizing agent. It seems that the choice of hydroxides of the involved cations as precursor reagents is crucial for the success of the crystal growth, via water vapor transport reactions. NdNiO3 was investigated by X-ray powder and single crystal diffraction at 123 and 292 K: GdFeO3 type, Pbnm, a = 538.10(7), b = 537.91(7), c = 760.26(10) pm, wR2 = 0.0434, 338 F2 values, and 29 variables at 292 K. The lowtemperature data gave no hint for a monoclinic distortion: Pbnm, a = 537.91(8), b = 538.49(8), c = 760.02(12) pm, wR2=0.0299, 338 F2 values, and 29 variables. At room temperature, the Ni–O distances vary from 193.9 to 194.2 pm, and the O–Ni–O angles cover the range from 89.5 to 90.5◦. Similar small distortions are observed for the NiO6 octahedra at 123 K. Due to the strong orthorhombic distortion, the neodymium atoms have only nine oxygen neighbors at Nd–O distances from 236.0 to 295.7 pm
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