3,950 research outputs found
Short-range order and precipitation in Fe-rich Fe-Cr alloys: Atomistic off-lattice Monte Carlo simulations
Short-range order (SRO) in Fe-rich Fe-Cr alloys is investigated by means of
atomistic off-lattice Monte Carlo simulations in the semi-grand canonical
ensemble using classical interatomic potentials. The SRO parameter defined by
Cowley [Phys. Rev. B 77, 669 (1950)] is used to quantify the degree of
ordering. In agreement with experiments a strong ordering tendency in the Cr
distribution at low Cr concentrations (~< 5%) is observed, as manifested in
negative values of the SRO parameters. For intermediate Cr concentrations (5%
~< c_Cr ~< 15%) the SRO parameter for the alpha-phase goes through a minimum,
but at the solubility limit the alpha-phase still displays a rather strong SRO.
In thermodynamic equilibrium for concentrations within the two-phase region the
SRO parameter measured over the entire sample therefore comprises the
contributions from both the alpha and alpha-prime phases. If both of these
contributions are taken into account, it is possible to quantitatively
reproduce the experimental results and interpret their physical implications.
It is thereby shown that the inversion of the SRO observed experimentally is
due to the formation of stable (supercritical) alpha-prime precipitates. It is
not related to the loss of SRO in the alpha-phase or to the presence of
unstable (subcritical) Cr precipitates in the alpha-phase.Comment: 9 pages, 8 figure
Solunto archaeological park in Sicily: life under mosaic tesserae
Biodeterioration is a complex process induced by the growing and metabolic activity of a wide range of macro and microorganisms, becoming a revelling problem also for the mosaic tesserae of âCasa di Ledaâ in the Greco - Roman site of Solunto in Sicily.
In this case-study, a thick biofilm inducing a deep alteration of mortar and consequently the mosaic tesserae detachment has been highlighted during the restoration plan.
The biofilm microbial consortium has been investigated by an integrate approach based on Microscopy analysis (O.M., C.L.S.M.), in vitro culture (Nutrien and Saboraud media) and molecular biology investigation (DNA target sequence amplification, sequencing, sequence analysis).
A microbial diversity has been revealed belonging to bacteria (Bacillus) and fungi (Alternaria, Aspergillus), besides cyanobacteria (Chroococcus) and green algae (Chlorella).
In order to control the biofilm colonization two essential oils (EO), Thymus vulgaris and Origanum vulgare, have been utilized and their antimicrobial activity, preliminarily in vitro (agar disc diffusion methods) and after ex situ and in situ evaluated. This experimentation is aimed at identifying and implementing green biocides for the control of microbial colonization, a promising technology with a reduced impact on human health and environment, able to replace traditional biocide action
Green next-generation excipients enriched in polyphenols from recovery of grape processing waste black bentonite: Influence of unconventional extraction solvents on antioxidant properties and composition
According to the UN Agenda 2030, several actions could be taken to act synergistically towards various areas of critical importance for both the humanity and the planet. Among them, the application of a circular economy model based on the valorisation of the wastes from the local resources could be a virtuous attitude. In this view, this work proposes a dual green approach for recovery of the waste black bentonite from the fining of organic white grape must. Indeed, this virtuous recovery idea is enhanced by the choice of both eco-friendly extraction method (maceration) and solvents. The latter were unconventional solvents selected among the pharmaceutic/cosmetic liquid hydrophilic excipients (waste-to-market approach) characterized by safety and high solvent power toward polyphenols. PEGs (200, 400, 600), Propylene Glycol and Glycerol
were tested and the extracted compared by HPLC-DAD analyses as well as the Folin-Ciocalteu, DPPH and Bradford assays. PEG200 emerged as the best one, leading to coloured extract containing great amount of polyphenols (3.123 ± 0.106 mg/g) and specifically Quercetin (60.778 ± 2.307 Όg/mL), which confer it interesting scavenger properties, potentially making it directly useful in a wide range of fields from the pharmaceutic to the cosmetic ones
Chemical vapor deposition of iron, iron carbides, and iron nitride films from amidinate precursors
Iron bis(N,N-diisopropylacetamidinate) [Fe2(”-iPr-MeAMD)2(2-iPr-MeAMD)2] and iron bis(N,N-di-tert-butylacetamidinate) [Fe(tBu-MeAMD)2] were used as precursors for the metallorganic chemical vapor deposition (MOCVD) of iron-containing compounds including pure iron, iron carbides, Fe3C and Fe4C, and iron nitrides Fe4C. Their decomposition mechanism involves hydrogen migration followed by dissociation of the FeâN bond and the release of free hydrogenated ligand (HL) and radicals. Surface intermediates are either released or decomposed on the surface providing FeâN or FeâC bonds. MOCVD experiments were run at 10 Torr, in the temperature ranges of 350â450°C with Fe2(”âiPr-MeAMD)2(2-iPr-MeAMD)2 and 280â350°C with Fe(tBu-MeAMD)2. Films prepared from Fe2(”âiPr-MeAMD)2(2-iPr-MeAMD)2 contain Fe, Fe3C, and Fe4C. Those prepared from Fe(tBu-MeAMD)2 contain Fe, Fe3C, and also Fe4C or Fe4N, depending on the temperature and hydrogen to precursor ratio (H/P) in the input gas. The room-temperature coercive field of films processed from Fe(tBu-MeAMD)2 is 3 times higher than that of the high temperature processed Fe4N films
pPKCα mediated-HIF-1α activation related to the morphological modifications occurring in neonatal myocardial tissue in response to severe and mild hyperoxia
In premature babies birth an high oxygen level exposure can occur and newborn hyperoxia exposure can be associated with free radical oxygen release with impairment of myocardial function, while in adult animal models short exposure to hyperoxia seems to protect heart against ischemic injury. Thus, the mechanisms and consequences which take place after hyperoxia exposure are different and related to animals age. The aim of our work has been to analyze the role played by HIF-1α in the occurrence of the morphological modifications upon hyperoxia exposure in neonatal rat heart. Hyperoxia exposure induces connective compartment increase which seems to allow enhanced blood vessels growth. An increased hypoxia inducible factor-1α (HIF-1α) translocation and vascular endothelial growth factor (VEGF) expression has been found upon 95% oxygen exposure to induce morphological modifications. Upstream pPKC-α expression increase in newborn rats exposed to 95% oxygen can suggest PKC involvement in HIF-1α activation. Since nitric oxide synthase (NOS) are involved in heart vascular regulation, endothelial NOS (e-NOS) and inducible NOS (i-NOS) expression has been investigated: a lower eNOS and an higher iNOS expression has been found in newborn rats exposed to 95% oxygen related to the evidence that hyperoxia provokes a systemic vasoconstriction and to the iNOS pro-apoptotic action, respectively. The occurrence of apoptotic events, evaluated by TUNEL and Bax expression analyses, seems more evident in sample exposed to severe hyperoxia. All in all such results suggest that in newborn rats hyperoxia can trigger oxygen free radical mediated membrane injury through a pPKCα mediated HIF-1α signalling system, even though specificity of such response could be obtained by in vivo administration to the rats of specific inhibitors of PKCα. This intracellular signalling can switch molecular events leading to blood vessels development in parallel to pro-apoptotic events due to an immature anti-oxidant defensive system in newborn rat hearts
Development and characterization of an amorphous solid dispersion of furosemide in the form of a sublingual bioadhesive film to enhance bioavailability
Administered by an oral route, Furosemide (FUR), a diuretic used in several edematous states and hypertension, presents bioavailability problems, reported as a consequence of an erratic gastrointestinal absorption due to various existing polymorphic forms and low and pH-dependent solubility. A mucoadhesive sublingual fast-dissolving FUR based film has been developed and evaluated in order to optimize the bioavailability of FUR by increasing solubility and guaranteeing a good dissolution reproducibility. The Differential Scanning Calorimetry (DSC) analyses confirmed that the film prepared using the solvent casting method entrapped FUR in the amorphous state. As a solid dispersion, FUR increases its solubility up to 28.36 mg/mL. Drug content, thickness, and weight uniformity of film were also evaluated. The measured Young\ue2\u80\u99s Modulus, yield strength, and relative elongation of break percentage (EB%) allowed for the classification of the drug-loaded film as an elastomer. Mucoadhesive strength tests showed that the force to detach film from mucosa grew exponentially with increasing contact time up to 7667 N/m2. FUR was quickly discharged from the film following a trend well fitted with the Weibull kinetic model. When applied on sublingual mucosa, the new formulation produced a massive drug flux in the systemic compartment. Overall, the proposed sublingual film enhances drug solubility and absorption, allowing for the prediction of a rapid onset of action and reproducible bioavailability in its clinical application
Neurotensin receptor 1 immunoreactivity in the peripheral ganglia and carotid body
In the present study we investigated, through immunohistochemistry, the presence and location of neurotensin receptor 1 (NTR1) in the peripheral ganglia and carotid body of 16 humans and 5 rats. In both humans and rats, NTR1 immunostained ganglion cells were found in superior cervical ganglia (57.4±11.6% and 72.4±11.4%, respectively, p<0.05), enteric ganglia (51.9±10.4% and 64.6±6.1%, p<0.05), sensory ganglia (69.2±10.7% and 73.0±13.1%, p>0.05) and parasympathetic ganglia (52.1±14.1% and 59.4±14.0%, p>0.05), supporting a modulatory role for NT in these ganglia. Positivity was also detected in 45.6±9.2% and 50.8±6.8% of human and rat type I glomic cells, respectively, whereas type II cells were negative. Our findings suggest that NT produced by type I cells acts in an autocrine or paracrine way on the same cell type, playing a modulatory role on chemoception
The missing link of circularity in small breweriesâ value chains: Unveiling strategies for waste management and biomass valorization
Despite the large quantities and possibilities of reuse of the by-products (solids and liquids) generated by the brewing industry, the proper disposal of these by-products has imposed severe problems for circular and cleaner production transitions worldwide. These challenges are still more salient for the small breweries due to the recognized lack of resources, such as knowledge, finances, and skilled staff. To address this problem, this article aims to identify sustainable strategies for waste management and biomass valorization that can be implemented in the value chain of small breweries. A mixed-method approach was implemented for the data collection and analysis to expand the evidence of the findings, including interviews with 18 small breweries and six specialists in the sector. We found that breweries mainly dispose of the by-products for animal feeding, although industry experts and the specialized literature indicate that at least 21 reuse and recycling alternatives have not been implemented in the value chain. Findings add to the literature five new alternatives informed by companies and six informed by experts for circular and cleaner production realization in small breweries' value chains. Furthermore, the article proposes a novel conceptual model to facilitate waste management and biomass valorization realization in small breweries value chains. Findings provide new insights that complement previous studies to overcome the challenges for waste management and biomass valorization in the sector. The article offers implications for theory, policymakers and managerial practice with repercussions on the production, environmental and financial issues
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