Search results for "Dehydration"

Management of Listeria monocytogenes on Surfaces via Relative Air Humidity: Key Role of Cell Envelope

2021

International audience; Although relative air humidity (RH) strongly influences microbial survival, its use for fighting surface pathogens in the food industry has been inadequately considered. We asked whether RH control could destroy Listeria monocytogenes EGDe by envelope damage. The impact of dehydration in phosphate-buffered saline (PBS) at 75%, 68%, 43% and 11% RH on the bacterial envelope was investigated using flow cytometry and atomic force microscopy. Changes after rehydration in the protein secondary structure and peptidoglycan were investigated by infrared spectroscopy. Complementary cultivability measurements were performed by running dehydration–rehydration with combinations o…

Supported H3PW12O40 for 2-propanol (photo-assisted) catalytic dehydration in gas-solid regime: The role of the support and of the pseudo-liquid phase…

2016

Abstract Catalytic and photocatalytic 2-propanol dehydration was carried out by using a supported Keggin heteropolyacid H3PW12O40 (PW12). Binary materials were prepared by impregnation and/or solvothermal treatment by using commercial supports: SiO2 (Mallinckrodt), TiO2 (Evonik P25) and multiwall carbon nanotubes (Sunnano) or home solvothermically prepared SiO2 and TiO2. All the materials have been characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with EDX microanalysis, specific surface area measurements, diffuse reflectance spectroscopy (DRS), FTIR and Raman spectroscopy. (Photo)catalytic 2-propanol dehydration was studied in gas-solid regim…

CRYOPRESERVATION OF PEACH SHOOT TIPS BY ENCAPSULATION DEHYDRATION

2011

Cryopreservation of Italian cultivars of hazelnut

2021

The present study was performed to optimise the cryopreservation protocol in Italian cultivars of Corylus avellana L. Lateral buds excised from in vitro grown plantlets of ‘Tonda Gentile Romana’ (TGR) and ‘Montebello’ (MB) were cryopreserved by the encapsulation-dehydration technique. The effect of dehydration of beads with sucrose (0.5, 0.75 or 1 M) for 1 or 3 days, of desiccation with silica gel for 6 or 8 h and of application of two cytokinins (N6-benzyladenine or meta-Topolin) in the regrowth phase was evaluated. The highest regrowth was obtained dehydrating alginate beads with 0.75 M sucrose applied for 1 day and with desiccation for 8 h with silica gel in both cultivars. On the other …

Immobilisation of yeast cells on the surface of hydroxyapatite ceramics

2011

Hydroxyapatite (HAP) ceramics was tested for the first time for the possibility of being used as a new carrier for the immobilisation of yeast cells that are both model organisms for eukaryotic cell investigations and producers, which is important in classical and modern biotechnological processes. It was shown that under typical immobilisation conditions yeast (Saccharomyces cerevisiae) has no affinity to HAP ceramics. A novel method for yeast immobilisation was developed. This new method includes the joint incubation of a carrier with the cells, the sedimentation and adhesion of cells on the carrier and the dehydration of obtained preparations. It was shown that the sedimentation and adhe…

Dehydration potential of ultrathin clouds at the tropical tropopause

2003

[1] We report on the first simultaneous in situ and remote measurements of subvisible cirrus in the uppermost tropical troposphere. The observed cirrus, called UTTCs ( ultrathin tropical tropopause clouds), are the geometrically (200-300 m) and optically (t approximate to 10(-4)) thinnest large-scale clouds ever sampled (approximate to10(5) km(2)). UTTCs consist of only a few ice particles per liter with mean radius approximate to5 mum, containing only 1-5 % of the total water. Yet, brief adiabatic cooling events only 1-2 K below mean ambient temperature destabilize UTTCs, leading to large sedimenting particles (r approximate to 25 mm). Due to their extreme altitude above 17 km and low part…

Physical pre-treatment of plums (Prunus domestica). Part 1. Modelling the kinetics of drying

2002

An alternative physical method for enhancing the drying rate of plums is proposed. It consists of the superficial abrasion of the plums' peel using an inert abrasive material to remove the cuticular waxy layer, the limiting factor for moisture loss. The physical pre-treatment was compared with a chemical treatment in which the plums were dipped into a solution of ethyl oleate. The drying kinetics of the above samples, including the untreated one, were reconstructed by using a mathematical model. The drying process, carried out at 60 C to reduce the prunes' quality loss, showed the great capability of both pre-treatments to enhance water diffusivity in the plum peel with respect to the untre…

Hydrothermal Synthesis, Crystal Structure, and Magnetism of Na 2 [Ir(OH) 6 ] and its Dehydration to Na 2 IrO 3

2021

Enhanced (photo)catalytic activity of Wells-Dawson (H6P2W18O62) in comparison to Keggin (H3PW12O40) heteropolyacids for 2-propanol dehydration in gas…

2016

Abstract Catalytic and photocatalytic 2-propanol dehydration to propene at atmospheric pressure and a temperature range of 60–120 °C were carried out in gas-solid regime by using bare and supported Keggin H 3 PW 12 O 40 (PW 12 ) and Wells-Dawson H 6 P 2 W 18 O 62 (P 2 W 18 ) heteropolyacids (HPAs). Binary materials were prepared by impregnation of the HPAs on commercial SiO 2 and TiO 2 . The Wells-Dawson was in any case more active than the Keggin heteropolyacid and the differences were enhanced when the supported samples were used. In particular, Wells-Dawson HPA supported on TiO 2 and under irradiation showed the highest activity. The HPA species played the key role both in the catalytic …

Responses of Prunus ferganensis, Prunus persica and two interspecific hybrids to moderate drought stress

2003

Prunus ferganensis (Kost. & Riab) Kov. & Kost, a close relative of the cultivated peach (Prunus persica (L.) Batsch.), is native to arid regions of central Asia and may possess traits valuable for improving drought tolerance of commercial peach varieties. One distinguishing feature of P. ferganensis is its prominent, elongated, unbranched leaf venation pattern, which behaves as a simple recessive trait in segregating populations of P. ferganensis x P. persica hybrids. To understand whether this trait could be used as a marker in breeding for drought tolerance, we investigated the association between leaf morphological and physiological parameters related to drought response in P. ferganensi…