233 research outputs found

    Reflection High-Energy Electron Diffraction oscillations during epitaxial growth of artificially layered films of (BaCuOx)m /(CaCuO2)n

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    Pulsed Laser Deposition in molecular-beam epitaxy environment (Laser-MBE) has been used to grow high quality BaCuOx/CaCuO2 superlattices. In situ Reflection High Energy Electron Diffraction (RHEED) shows that the growth mechanism is 2-dimensional. Furthermore, weak but reproducible RHEED intensity oscillations have been monitored during the growth. Ex-situ x-ray diffraction spectra confirmed the growth rate deduced from RHEED oscillations. Such results demonstrate that RHEED oscillations can be used, even for (BaCuOx)2/(CaCuO2)2 superlattices, for phase locking of the growth.Comment: 9 pages, 5 figures. Corresponding author: Dr. A. Tebano: [email protected]

    EMISSIONS REDUCTION FROM PELLET STOVESTHROUGH BURNER POT MODIFICATIONS

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    In this study, results of an extensive set of experiments onfive wood pellet stoves (8-11 kW nominal power) have been per-formed to verify whether carbon monoxide (CO), particulatematter (PM) and nitrogen monoxide (NO) emissions can be re-duced upon modification of burner pot geometry, depth and airinlet positions. A modification of “traditional” burner pot geom-etry brings CO emission close to zero. Also PM emissions arereduced but not as much as those of CO. It is verified that increas-ing the burner pot’s depth, PM emissions can be further reducedcompared to the less deep burner pot. Finally, since plots of in-stantaneous emissions versus O2content exhibit significant scat-tering and do not show a clear correlation, plots of mean valueof emissions, over narrow intervals of O2, versus O2are intro-duced. These plots show an optimal interval of O2content thatminimizes emissions

    Differential Physiological Responses Elicited by Ancient and Heritage Wheat Cultivars Compared to Modern Ones.

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    Although ancient, heritage, and modern wheat varieties appear rather similar from a nutritional point of view, having a similar gluten content and a comparable toxicity linked to their undigested gluten peptide, whenever the role of ancient end heritage wheat grains has been investigated in animal studies or in clinical trials, more anti-inflammatory effects have been associated with the older wheat varieties. This review provides a critical overview of existing data on the differential physiological responses that could be elicited in the human body by ancient and heritage grains compared to modern ones. The methodology used was that of analyzing the results of relevant studies conducted from 2010 through PubMed search, by using as keywords "ancient or heritage wheat", "immune wheat" (protein or peptides), and immune gluten (protein or peptides). Our conclusion is that, even if we do not know exactly which molecular mechanisms are involved, ancient and heritage wheat varieties have different anti-inflammatory and antioxidant proprieties with respect to modern cultivars. It is, therefore, reasonable to assume that the health proprieties attributed to older cultivars could be related to wheat components which have positive roles in the modulation of intestinal inflammation and/or permeability

    Long-term data prove useful to keep track of non-indigenous seaweed fate

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    The Mar Piccolo of Taranto (southern Italy, Mediterranean Sea), a site of the European LTER network, is a transitional water system, where a century-old intensive mussel farming activity has been carried out, together with an intense import-export business of bivalve mollusks. Previous studies showed that this basinisthirdforNISseaweedintroductionintheMediterraneanSea,aftertheThau LagoonandtheVeniceLagoon.Thepresentpaperdealswiththeresultsof11-year monitoring activity on non-indigenous species (NIS) of seaweeds, which was performed in the Mar Piccolo. In the studied period (2011–2021), two different time frames (i.e., 2011–2015 and 2016–2021) were considered, since they were based on a different number of sampling sites. To investigate spatial and temporal differences in the seaweed assemblage, a multivariate analysis was performed considering the NIS and the most important native species in terms of temporal occurrence. Fourteen NIS were recorded in total in the Mar Piccolo of Taranto duringthisperiod,withvariableabundancesamongsitesandyears:ninespeciesin the firsttimeperiod,andthirteenspeciesinthesecondone.Caulerpacylindracea, recorded with negligible biomass in the first period, was absent in the secondperiod samplings. Molecular analyses confirmed the taxonomy of three species (i.e., Grateloupia minima, Neopyropia koreana, and Polysiphonia morrowii), previously identified only through morphological features. The most abundant specieswasHypneacorona,whichalmostdoubleditsbiomassinthesecondtime period compared to the first one. Three species (i.e., Caulacanthus okamurae, G. minima, and P. morrowii) increased their biomass by an order of magnitude in the second time period. No significant differences were found over years. Site 1 resulted in significant differences among the sites and different seasonal pattern occurred among the investigated sites. No significant long-term changes occurred in the seaweed assemblages, suggesting the absence of strong disturbances due to the settlement of NIS

    Optical conductivity of CuO_2 infinite-layer films

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    The infrared conductivity of CaCuO_2, SrCuO_{2-y}, and Sr_{0.85}Nd_{0.15}CuO_2 infinite-layer films is obtained from reflectivity measurements by taking into account the substrate contribution. SrCuO_{2-y} and Sr_{0.85}Nd_{0.15}CuO_2 exhibit extra-phonon modes and structured bands in the midinfrared, not found in stoichiometric CaCuO_2. These features mirror those observed in the perovskitic cuprates, thus showing that the polaronic properties of high-T_c superconductors are intrinsic to the CuO_2 planes.Comment: File latex, 5 p. incl. 4 fig. in epsf. Submitted to Solid State Com

    A network perspective to the measurement of sense of coherence (SOC): an exploratory graph analysis approach

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    The measurement of sense of coherence (SOC) has received attention for more than three decades. Despite the extensive use of SOC-13, there is still a long debate regarding its dimensionality structure. Recently, there has been an increasing use of network modeling as a valid alternative to latent-variable modeling. This study proposes an exploratory approach to the structure of SOC-13 by adopting a network perspective. The network structure was estimated with a Gaussian Graphical Model, and Exploratory Graph Analysis (EGA) was used to inspect network dimensionality. We fit and compared the unidimensional, first- and second-order confirmatory factor analysis (CFA), bifactor-CFA, and structure derived from EGA. Our results showed unacceptable fit values for the CFA models, suggesting that SOC-13 is not unidimensional. Inspection of the estimated network suggested that the SOC-13 items emerged as a dynamic system of mutually interacting nodes that formed three distinct clusters of items (communities) that are not those defined in the literature. EGA identified three communities of items: the first community was characterized by comprehensibility and manageability items, the second community was characterized by comprehensibility and manageability items, and the third dimension was characterized by all meaningfulness items and one comprehensibility item. Our study presented a novel perspective in investigating the structure of SOC-13 that strengthens the assumption that SOC should be conceptualized as a complex system of cognitive (comprehensibility), behavioral (manageability), and motivational dimensions (meaningfulness) that are deeply linked and not necessarily distinct

    Does femtosecond time-resolved second-harmonic generation probe electron temperatures at surfaces?

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    Femtosecond pump-probe second-harmonic generation (SHG) and transient linear reflectivity measurements were carried out on polycrystalline Cu, Ag and Au in air to analyze whether the electron temperature affects Fresnel factors or nonlinear susceptibilities, or both. Sensitivity to electron temperatures was attained by using photon energies near the interband transition threshold. We find that the nonlinear susceptibility carries the electron temperature dependence in case of Ag and Au, while for Cu the dependence is in the Fresnel factors. This contrasting behavior emphasizes that SHG is not a priori sensitive to electron dynamics at surfaces or interfaces, notwithstanding its cause.Comment: 11 pages, 4 figure

    Cytochalasin B Influences Cytoskeletal Organization and Osteogenic Potential of Human Wharton’s Jelly Mesenchymal Stem Cells

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    Among perinatal stem cells of the umbilical cord, human Wharton’s jelly mesenchymal stem cells (hWJ-MSCs) are of great interest for cell-based therapy approaches in regenerative medicine, showing some advantages over other MSCs. In fact, hWJ-MSCs, placed between embryonic and adult MSCs, are not tumorigenic and are harvested with few ethical concerns. Furthermore, these cells can be easily cultured in vitro, maintaining both stem properties and a high proliferative rate for several passages, as well as trilineage capacity of differentiation. Recently, it has been demonstrated that cytoskeletal organization influences stem cell biology. Among molecules able to modulate its dynamics, Cytochalasin B (CB), a cyto-permeable mycotoxin, influences actin microfilament polymerization, thus affecting several cell properties, such as the ability of MSCs to differentiate towards a specific commitment. Here, we investigated for the first time the effects of a 24 h-treatment with CB at different concentrations (0.1–3 μM) on hWJ-MSCs. CB influenced the cytoskeletal organization in a dose-dependent manner, inducing changes in cell number, proliferation, shape, and nanomechanical properties, thus promoting the osteogenic commitment of hWJ-MSCs, as confirmed by the expression analysis of osteogenic/autophagy markers

    Do olfactory and gustatory psychophysical scores have prognostic value in COVID-19 patients? A prospective study of 106 patients

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    Background: The lack of objective data makes it difficult to establish the prognostic value of chemosensitive disorders in coronavirus disease 2019 (COVID-19) patients. We aimed to prospectively monitor patients diagnosed with COVID-19 to see if the severity of olfactory and gustatory dysfunction associates with subsequent disease severity. Methods: Multicentre prospective study that recruited 106 COVID-19 subjects at diagnosis. Chemosensitive functions were assessed with psychophysical tests within 4 days of clinical onset, at 10 and 20 days. Daily body temperature and oxygen saturation were recorded as markers of disease severity alongside need for hospitalisation. The correlation between olfactory and gustatory scores and disease severity was assessed with linear regression analysis. Results: At T0, 71 patients (67%) presented with olfactory dysfunction while gustatory impairment was detected in 76 cases (65.6%). Chemosensitive disorders gradually improved over the observation period. No significant correlations were found between T0 chemosensitive scores and final disease severity. The correlation between olfactory scores and fever proved significant at T2 (p = 0.05), while the relationship with gustatory scores was significant at T1 (p = 0.01) and T2 (p < 0.001), however neither was clinically relevant. The correlation between chemosensitive scores and oxygen saturation was significant only for taste at T2 (p < 0.001). Logistic regression analysis found significant correlations between olfactory impairment severity and need for hospitalization at T2 (OR 3.750, p = 0.005). Conclusions: Initial objective olfactory and gustatory scores do not seem to have a significant prognostic value in predicting the severity of the COVID-19 course; however, persistence of olfactory dysfunction at 20 days, associated with a more severe course. Unfortunately, olfactory and gustatory dysfunction do not seem to hold prognostic value at the time of initial diagnosis
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