492 research outputs found

    Assessment of total (anti)oxidant status in goat kids

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    The redox potential of goat serum was assessed by different spectrophotometric assays. Among them, three methods are commonly applied for the evaluation of the oxidative (reactive oxygen metabolites, ROMs, and total oxidant status, TOS) and nitrosative (NO q metabolites, NOx ) stress, and four methods for the evaluation of the antioxidant status: the total antioxidant capacity (TAC) based on the ferric reducing ability of plasma (FRAP), the total antioxidant activity (TAA) based on the reduction of the coloured ABTS•+radical cation, the free radical scavenging activity (FRSA) based on the reduction of the purple DPPH•, and the total thiol levels (TTLs) based on their interaction with DTNB to form a highly coloured anion. Besides, myeloperoxidase (MPO) and ceruloplasmin oxidase (CP) activities were also assessed. Except for TAA, analytical data showed a great inter-individual variation for both oxidant and antioxidant assays. ROMs were strongly correlated with CP, while TOS with MPO and TAC. Furthermore, a tendency between TOS and FRSA was shown. NOx was correlated with TAC and TAA, and a tendency with TOS was shown. No correlations appeared among the antioxidant assays, even if a tendency between TAC and TAA was evidenced, but TAC was correlated with MPO activity. The observed correlation between ROMs and CP is discussed as a possible analytical interference. The absence of correlation among the antioxidant biomarkers suggests the simultaneous use of a panel of tests to verify any changes in the redox balance, mainly in livestock in which reference values for each biomarker are lacking

    MAPPA. Methodologies applied to archaeological potential Predictivity

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    The fruitful cooperation over the years between the university teaching staff of Univerità di Pisa (Pisa University), the officials of the Soprintendenza per i Beni Archeologici della Toscana (Superintendency for Archaeological Heritage of Tuscany), the officials of the Soprintendenza per i Beni Architettonici, Paesaggistici, Artistici ed Etnoantropologici per le Province di Pisa e Livorno (Superintendency for Architectural, Landscape and Ethno-anthropological Heritage for the Provinces of Pisa and Livorno), and the Comune di Pisa (Municipality of Pisa) has favoured a great deal of research on issues regarding archaeological heritage and the reconstruction of the environmental and landscape context in which Pisa has evolved throughout the centuries of its history. The desire to merge this remarkable know-how into an organic framework and, above all, to make it easily accessible, not only to the scientific community and professional categories involved, but to everyone, together with the wish to provide Pisa with a Map of archaeological potential (the research, protection and urban planning tool capable of converging the heritage protection needs of the remains of the past with the development requirements of the future) led to the development of the MAPPA project – Methodologies applied to archaeological potential predictivity - funded by Regione Toscana in 2010. The two-year project started on 1 July 2011 and will end on 30 June 2013. The first year of research was dedicated to achieving the first objective, that is, to retrieving the results of archaeological investigations from the archives of Superintendencies and University and from the pages of scientific publications, and to making them easily accessible; these results have often never been published or have often been published incompletely and very slowly. For this reason, a webGIS (“MappaGIS” that may freely accessed at http://mappaproject.arch.unipi.it/?page_id=452) was created and will be followed by a MOD (Mappa Open Data archaeological archive), the first Italian archive of open archaeological data, in line with European directives regarding access to Public Administration data and recently implemented by the Italian government also (the beta version of the archive can be viewed at http://mappaproject.arch.unipi.it/?page_id=454). Details are given in this first volume about the operational decisions that led to the creation of the webGIS: the software used, the system architecture, the organisation of information and its structuring into various information layers. But not only. The creation of the webGIS also gave us the opportunity to focus on a series of considerations alongside the work carried out by the MAPPA Laboratory researchers. We took the decision to publish these considerations with a view to promoting debate within the scientific community and, more in general, within the professional categories involved (e.g. public administrators, university researchers, archaeology professionals). This allowed us to overcome the critical aspects that emerged, such as the need to update the archaeological excavation documentation and data archiving systems in order to adjust them to the new standards provided by IT development; most of all, the need for greater and more rapid spreading of information, without which research cannot truly progress. Indeed, it is by comparing and connecting new data in every possible and, at times, unexpected way that research can truly thrive

    PEG reimplantation after Buried Bumper Syndrome: a case report

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    Percutaneous endoscopic gastrostomy (PEG) is the method of choice to provide long-term enteral nutrition for patients with impossibility to be fed orally. Although it is considered a routine and safe procedure, potential complications exist, which are generally classified into three major categories: endoscopic technical difficulties, PEG procedure-related complications and late complications associated with PEG tube use, such as buried bumper syndrome (BBS). BBS is a potentially life-threatening complication, occurring in 0.3% to 2.5% of cases. Additional complications related to BBS may present, such as wound infection, peritonitis, and necrotizing fasciitis. Once resolved the acute complication, an adequate feeding method should be prompted for the patient, among whom PEG remains of choice. After tissue inflammation, fibrosis may prevent a standard endoscopic procedure for the new implantation, therefore endoscopists should modulate procedures to obtain successful and safe results. A combined surgical-and endoscopic strategy could resolve implantation difficulties ensuring a safe and simple procedure. We present here a case of BBS complicated with abdominal wall cellulitis in a paraplegic 35-year-old-man who was admitted to our hospital. (www.actabiomedica.it)

    The 2006 hot phase of Romano's star (GR 290) in M33

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    Understanding the nature of the instabilities of LBVs is important to understand the late evolutionary stages of very massive stars. We investigate the long term, S Dor-type variability of the luminous blue variable GR290 (Romano's star) in M33, and its 2006 minimum phase. New spectroscopic and photometric data taken in November and December 2006 were employed in conjunction with already published data on GR290 to derive the physical structure of GR290 in different phases and the time scale of the variability. We find that by the end of 2006, GR 290 had reached the deepest visual minimum so far recorded. Its present spectrum resembles closely that of the Of/WN9 stars, and is the hottest so far recorded in this star (and in any LBV as well), while its visual brightness decreased by about 1.4 mag. This first spectroscopic record of GR290 during a minimum phase confirms that, similarly to AG Car and other LBVs, the star is subject to ample S Dor-type variations, being hotter at minimum, suggesting that the variations take place at constant bolometric luminosity.Comment: 4 figures, 1 table, accepted for publication in A&A Letter

    GR 290 (Romano's Star): 2. Light history and evolutionary state

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    We have built the historical light curve of the luminous variable GR 290 back to 1901, from old observations of the star found in several archival plates of M 33. These old recordings together with published and new data show that for at least half a century the star was in a low luminosity state, with B ~18. After 1960, five large variability cycles of visual luminosity were recorded. The amplitude of the oscillations was seen increasing towards the 1992-1994 maximum, then decreasing during the last maxima. The recent light curve indicates that the photometric variations have been quite similar in all the bands, and that the B-V color index has been constant within +/-0.1 m despite the 1.5m change of the visual luminosity. The spectrum of GR 290 at the large maximum of 1992-94, was equivalent to late-B type, while, during 2002-2014, it has varied between WN10h-11h near the visual maxima to WN8h-9h at the luminosity minima. We have detected, during this same period, a clear anti-correlation between the visual luminosity, the strength of the HeII 4686 A emission line, the strength of the 4600-4700 A lines blend and the spectral type. From a model analysis of the spectra collected during the whole 2002-2014 period we find that the Rosseland radius R_{2/3}, changed between the minimum and maximum luminosity phases by a factor of 3, while T_eff varied between about 33,000 K and 23,000 K. The bolometric luminosity of the star was not constant, but increased by a factor of ~1.5 between minimum and maximum luminosity, in phase with the apparent luminosity variations. In the light of current evolutionary models of very massive stars, we find that GR 290 has evolved from a ~60 M_Sun progenitor star and should have an age of about 4 million years. We argue that it has left the LBV stage and is moving to a Wolf-Rayet stage of late nitrogen spectral type.Comment: Accepted on The Astronomical Journal, 10 figures. Replaced because the previous uploaded file was that without the final small corrections requested by the refere

    The pulsed electron deposition technique for biomedical applications: A review

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    The "pulsed electron deposition" (PED) technique, in which a solid target material is ablated by a fast, high-energy electron beam, was initially developed two decades ago for the deposition of thin films of metal oxides for photovoltaics, spintronics, memories, and superconductivity, and dielectric polymer layers. Recently, PED has been proposed for use in the biomedical field for the fabrication of hard and soft coatings. The first biomedical application was the deposition of low wear zirconium oxide coatings on the bearing components in total joint replacement. Since then, several works have reported the manufacturing and characterization of coatings of hydroxyapatite, calcium phosphate substituted (CaP), biogenic CaP, bioglass, and antibacterial coatings on both hard (metallic or ceramic) and soft (plastic or elastomeric) substrates. Due to the growing interest in PED, the current maturity of the technology and the low cost compared to other commonly used physical vapor deposition techniques, the purpose of this work was to review the principles of operation, the main applications, and the future perspectives of PED technology in medicine

    Textile chemical sensors based on conductive polymers for the analysis of sweat

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    Wearable textile chemical sensors are promising devices due to the potential applications in medicine, sports activities and occupational safety and health. Reaching the maturity required for commercialization is a technology challenge that mainly involves material science because these sensors should be adapted to flexible and light-weight substrates to preserve the comfort of the wearer. Conductive polymers (CPs) are a fascinating solution to meet this demand, as they exhibit the mechanical properties of polymers, with an electrical conductivity typical of semiconductors. Moreover, their biocompatibility makes them promising candidates for effectively interfacing the human body. In particular, sweat analysis is very attractive to wearable technologies as perspiration is a naturally occurring process and sweat can be sampled non-invasively and continuously over time. This review discusses the role of CPs in the development of textile electrochemical sensors specifically designed for real-time sweat monitoring and the main challenges related to this topic

    Organic Electrochemical Transistors as Versatile Analytical Potentiometric Sensors

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    Potentiometric transduction is an important tool of analytical chemistry to record chemical signals, but some constraints in the miniaturization and low-cost fabrication of the reference electrode are a bottleneck in the realization of more-advanced devices such as wearable and lab-on-a-chip sensors. Here, an organic electrochemical transistor (OECT) has been designed with an alternative architecture that allows to record the potentiometric signals of gate electrodes, which have been chemically modified to obtain Ag/AgnX interfaces (X = Cl−, Br−, I−, and S2−), without the use of a reference electrode. When the OECT is immersed in a sample solution, it reaches an equilibrium state, because PEDOT:PSS exchanges charges with the electrolyte until its Fermi level is aligned to the one of Ag/AgnX. The latter is controlled by Xn− concentration in the solution. As a consequence, in this spontaneous process, the conductivity of PEDOT:PSS changes with the electrochemical potential of the modified gate electrode without any external bias. The sensor works by applying only a fixed drain current or drain voltage and thus the OECT sensor operates with just two terminals. It is also demonstrated that, in this configuration, gate potential values extracted from the drain current are in good agreement with the ones measured with respect to a reference electrode being perfectly correlated (linear slope equal to 1.00 ± 0.03). In the case of the sulfide anion, the OECT performance overcomes the limit represented by the Nernst equation, with a sensitivity of 0.52 V decade−1. The presented results suggest that OECTs could be a viable option to fabricate advanced sensors based on potentiometric transduction

    Selective detection of liposoluble vitamins using an organic electrochemical transistor

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    Accurate quantification of vitamins content is essential in food analysis, with direct impact on the quality of our diet and, therefore, on our health. Current research interest is devoted to the design of robust and versatile devices able to perform real-time analyses that do not strictly rely on laboratory facilities. Here, we report the first organic electrochemical transistor (OECT) based sensor working in organic environment for the detection of a fat-soluble vitamin (Vitamin A). The OECT behaviour in organic solvents was thoroughly characterized and its structure was optimised allowing both potentiostatic and potentiodynamic detections. On one hand, the potentiostatic approach provided a gain of 100 and the detection limit was as low as 115 nM, but it did not address selectivity issues. On the other hand, the potentiodynamic approach showed a higher detection limit, but allowed the selective detection of Vitamin A in the presence of & alpha;-Tocopherol. Analyses of randomized solutions revealed that a pre-calibrated sensor can estimate Vitamin A concentration with a 3% error. Moreover, the robustness of our sensor was demonstrated by analysing commercial food fortifiers without any sample pretreatment
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