•A PTR-ToF-MS based protocol for the high-throughput analysis of wine is proposed.•Argon injected in the drift tube reduces the negative effect of ethanol.•Differentiation among wines from different ...geographical origin is achievable.•Wine fermented with different strains of Oenococcus oeni were discriminated.
PTR-ToF-MS has been previously used to analyse the headspace of wine, but it is not fully exploited in the field due to problems related to the high ethanol concentration. In the case of alcoholic fermentation during bread-making, we have recently proposed improvements to the method by introducing argon in the system in order to reduce fragmentation and formation of ethanol clusters. In this study, we optimize the experimental setup in the case of wine by (i) boosting the sampling protocol (sample headspace flushing and incubation); (ii) determining the optimal E/N value while using argon as carrier gas and (iii) proving that the optimized protocol reduces the effect of ethanol. The new protocol has been verified to discriminate eight French wines coming from three different regions (Gers, Gironde, Languedoc) and, in order to assess the applicability of the method in a relevant problem of oenological interest, we also tested it on a set of samples consisting of a red wine fermented with two different commercial preparations of Oenococcus oeni. Using principal component analysis of selected m/z signals, differentiation among wines from different geographical origin was achievable. Samples corresponding to the reference wine and to wines inoculated with two different commercial preparations were clearly separated. Intriguingly, our approach suggests the selective degradation of volatile organic compounds by O. oeni in wine as new possible feature of malolactic starter cultures in wine.
The enzyme system responsible for Amphibian Kupffer Cell (KC) melanogenesis has not been entirely elucidated. This research demonstrates that the KC melanosomes of Rana esculenta L. possess a ...tyrosine-hydroxylase (TH) activity, showing that a tyrosinase is the enzyme involved in the melanogenesis. The TH reaction depends on catalytic Dopa as a cofactor and is not affected by catalase or H2O2, showing that it is catalysed by the tyrosinase and not by the peroxidase present in the melanosomes. The TH reaction is activated by Cu2+ ions but not by other tyrosinase activators such as limited proteolysis, protein ageing, and Sodium Dodecyl Sulphate (SDS). SDS inhibited the KC TH activity even below the critical micelle concentration. All these results suggest that the KC-tyrosinase differs in structure from other known tyrosinases. Using anti-KC-tyrosinase antobodies, we observed that the sites of the tyrosinase location within the cell are the same as those described in the melanocytes. In the immunoblots, the anti-KC-tyrosinase antibodies also recognised two protein bands, at the higher molecular weight ranges, in the protein electrophoretic pattern. Moreover, the tyrosinase activity was limited to the highest molecular weight band of about 260 kDa, suggesting that the enzyme activity could depend on a molecular aggregate. The melanin produced in the liver was found to be a 5,6-dihydroxyindole-rich eumelanin similar to the Sepia melanin.
Among different radiotherapy techniques, proton irradiation is an established and effective method for treatment of several types of cancer, because less healthy tissue is exposed with respect to ...conventional radiotherapy by photons/electrons. Recently, proton therapy has been proposed for the treatment of breast cancer.
In vitro
studies of proton irradiated normal human breast cells can provide information about cellular radioresponse, particularly as far as healthy tissue is concerned. In this paper, a study of the effects at different time points, following proton irradiation at different doses, of human normal MCF10A breast cells is performed by Raman spectroscopy. The aim of this investigation is to detect the unwanted effects of proton treatment and to investigate the possibility of monitoring them and of making an assessment of the cellular sensitivity by means of such a technique. The obtained results seem to indicate a rather significant sensitivity of MCF10A cells to proton irradiation. In fact, even at doses as low as 0.5 Gy, biological effects are clearly detectable in Raman spectra. In particular, ratiometric analysis of the Raman spectra measured from the nucleoplasm compartment showed that DNA/RNA damage increases with time, suggesting that most cells are unable to repair DNA/RNA broken bonds. The results obtained by the Raman spectroscopy analysis exhibit a similar trend with regard to dose to those obtained by commonly used radiobiological assays (
i.e.
MTT, clonogenic assay, senescence, apoptosis and necrosis). The results of this study strongly suggest the possibility that the Raman technique can be used to identify molecular markers predicting radiation response.
Radiobiological effects occurring in normal human breast cells exposed to a low dose of a clinical proton beam are detectable by means of Raman spectra and the ratiometric analysis of Raman peak intensities.
Optical properties of CdSe and CdS films, deposited on sapphire substrate by means of pulsed laser ablation technique, have been investigated in order to study the effect of such a transparent ...substrate on the photoluminescence efficiency of the deposited epilayers. CdSe and CdS films present intrinsic (excitonic) emission at low temperature, differently from the same films deposited on quartz. The temperature dependence of the excitonic energy has been analyzed taking into account the contribution of both the thermal dilatation and electron–phonon interaction.
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•Study of untreated and hydrogenated rich-diamond and rich-graphite nanodiamond (ND) particles.•Quantum efficiencies (QE) of ND-based photocathodes measured by ...photoemission.•Stabilities of aqueous ND dispersions assessed by zeta potential (ZP).•Good correlation between the QE of photocathodes and the ZP of ND particles.
In this paper, we present an investigation on two types of nanodiamond (ND) powders with average size of particles around 250nm and having different sp2 (graphite phase) and sp3 (diamond phase) carbon contents. The ND surface modification is carried out by physical methods i.e. treatments in H2 microwave plasma. The quantum efficiency (QE) of photocathodes and the stability of aqueous dispersions are assessed by photoemission and zeta potential (ZP) measurements, respectively.
The resultant hydrogenated surface affects in the solid state the QE of ND-based photocathodes and in solution the particle ZP. The effect of the hydrogen treatment is beneficial inducing an enhancement of photocathode QE and a corresponding increase of the ZP. A schematized energy diagram is proposed to illustrate and explain the strong correlation between QE and ZP parameters.
Here we present the rescue of sub-daily meteorological observations collected from 1884 to 1963 at Montevergine Observatory, located in the Southern Apennines in Italy. The recovered dataset consists ...of 3-daily observations of the following atmospheric variables: dry-bulb temperature, wet-bulb temperature, water vapour pressure, relative humidity, atmospheric pressure, cloud type, cloud cover, rainfall, snowfall and precipitation type. The data, originally available only as paper-based records, have been digitized following the World Meteorological Organization standard practices. After a cross-check, the digitized data went through three different automatic quality control tests: the gross error test, which verifies whether the data are within acceptable range limits; the tolerance test, which flags whether values are above or below monthly climatological limits that are defined in accordance with a probability distribution model specific to each variable; and the temporal coherency test, which checks the rate of change and flags unrealistic jumps in consecutive values.
Deposition of thin films of ZnSe has been performed by means of pulsed laser deposition (PLD) technique, by varying the pulsed laser fluence. X-ray diffraction spectra shows that the films grow in ...the cubic phase, with a preferential orientation along the (1
0
0) direction. Reflectance spectra from 10 to 300
K in the excitonic resonance region have been analysed according to the classical oscillator model. The parameters that describe the temperature variation of the energy (including electron–phonon interaction and thermal expansion effects) and broadening of the bandgap have been evaluated. All the deposited films show photoluminescence at room temperature. This is promising for optoelectronic application of PLD technique.
Bacterial stressors in minimally processed food Capozzi, Vittorio; Fiocco, Daniela; Amodio, Maria Luisa ...
International Journal of Molecular Sciences,
07/2009, Letnik:
10, Številka:
7
Journal Article, Book Review
Recenzirano
Odprti dostop
Stress responses are of particular importance to microorganisms, because their habitats are subjected to continual changes in temperature, osmotic pressure, and nutrients availability. Stressors (and ...stress factors), may be of chemical, physical, or biological nature. While stress to microorganisms is frequently caused by the surrounding environment, the growth of microbial cells on its own may also result in induction of some kinds of stress such as starvation and acidity. During production of fresh-cut produce, cumulative mild processing steps are employed, to control the growth of microorganisms. Pathogens on plant surfaces are already stressed and stress may be increased during the multiple mild processing steps, potentially leading to very hardy bacteria geared towards enhanced survival. Cross-protection can occur because the overlapping stress responses enable bacteria exposed to one stress to become resistant to another stress. A number of stresses have been shown to induce cross protection, including heat, cold, acid and osmotic stress. Among other factors, adaptation to heat stress appears to provide bacterial cells with more pronounced cross protection against several other stresses. Understanding how pathogens sense and respond to mild stresses is essential in order to design safe and effective minimal processing regimes.
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