1,283 research outputs found

    Hereditary diaphorase deficiency methemoglobinemia in Maltese families

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    Methemoglobin (ferrihamoglobin) normally constitutes only 1% of the total hemoglobin of the red cells. Its presence in a greater concentration is pathological and may be due to a number of different causes, congenital or acquired. Hereditary Diaphorase Deficiency Methemoglobinemia was discovered in seven persons belonging to four Maltese families. These are the first families of diaphorase deficiency methemoglobinemia to be recorded from the Maltese Islands. The case reports of the seven affected individuals are hereby described and discussed with particular reference to other medical literature and studies. It is suggested that the gene frequency for this type of congenital methemoglobinemia is high in the Maltese Islands and that wider systematic surveys would reveal many more cases.peer-reviewe

    Circular dielectric cavity and its deformations

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    The construction of perturbation series for slightly deformed dielectric circular cavity is discussed in details. The obtained formulae are checked on the example of cut disks. A good agreement is found with direct numerical simulations and far-field experiments.Comment: 17 pages, 12 figure

    Antiproliferative Oleanane Saponins from Dizygotheca elegantissima

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    Four new oleanane saponins (1-4), together with three known saponins, were isolated from the aerial parts of Dizygotheca elegantissima R. Vig. & Guillaumin. Their structures were elucidated by 1D and 2D NMR experiments including 1D TOCSY, DQF-COSY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis. The antiproliferative activity of all isolated compounds was evaluated

    Converted phase identification and retrieval of Vp/Vs ratios from move-out reflection analysis: application to the Campi Flegrei caldera

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    Here, we propose a method for the determination of Vp/Vs ratios in a horizontally layered propagation media using maximization of a coherency function along theoretical travel-times of PS reflected phases. The theoretical travel-times are computed using the information about the propagation media that is extracted by velocity analysis or by topographic analysis performed on the first arrivals. The method is also a valid tool for the identification of the PS phases associated with a fixed seismic reflector, and it is particularly suitable for data that is stored in common mid-point and common conversion point bin- ning; for this kind of data the hypothesis of horizontally and layered media can usually be verified. We applied the method to both simulated and real datasets. The use of the real data that was acquired in the Campi Flegrei caldera (southern Italy) allowed us to estimate a relatively high Vp/Vs ratio (3.5 ± 0.6) for a very shallow layer (maximum depth, 600 m). This hypothesis has been tested by theoretical rock physical modeling of the Vp/Vs ratios as a function of porosity, suggesting that the shallow layer appears to be formed of unconsolidated, water-saturated, volcanic and marine sediments that filled Pozzuoli Bay during the post-caldera activity

    An alien invader is the cause of homogenization in the recipient ecosystem: a simulation-like approach.

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    Biotic homogenization is an expected effect of biological invasions. Invasive alien species typically show great adaptability to a wide range of environmental conditions and may expand into different habitats, thus reducing the dissimilarity among the recipient communities. We tested this assumption by analyzing a comprehensive database (78 species x 229 samples) collected between 2012 and 2017 in the marine protected area of Portofino (NW Italy), where Caulerpa cylindracea, one of the worst invaders in the Mediterranean Sea, exhibits high substratum cover at depths between 1 m and 45 m in 14 different communities (identified according to the European Nature Information System EUNIS for habitat classification). Five samples for each of the eight depth zones (i.e., 5 m, 10 m, 15 m, 20 m, 25 m, 30 m, 35 m, and 40 m) were randomly re-sampled from the comprehensive database to produce a dataset of 67 species x 40 samples. Then, a second dataset of 66 species x 40 samples was simulated by excluding Caulerpa cylindracea. Both re-sampled datasets underwent multivariate analysis. In the presence of C. cylindracea, the overall similarity among samples was higher, thus indicating homogenization of the rocky reef communities of Portofino Marine Protected Area. Continued monitoring activity is needed to understand and assess the pattern and extent of C. cylindracea\u2019s inclusion in the recipient ecosystems

    Bismuth vanadate photoanodes for water splitting deposited by radio frequency plasma reactive co-sputtering

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    Photoactive bismuth vanadate (BiVO4) thin coatings were deposited on fluorine-doped tin oxide glass by plasma reactive sputtering from Bi2O3 and vanadium (V) radio frequency (RF) powered targets. The films were characterized by x-ray diffraction, scanning electron microscopy, energy dispersion spectroscopy, and UV-vis spectroscopy. The effects that the power density supplied to the Bi2O3 target, the post-annealing treatment, and the film thickness have on the structural features and on the photoelectrochemical (PEC) performances of the so obtained BiVO4 film-based photoelectrodes were investigated. Their PEC performance in water splitting was evaluated in a three-electrode cell by both incident photon to current efficiency (IPCE) and linear sweep voltammetry measurements under AM 1.5 G simulated solar light irradiation. A monoclinic phase of BiVO4, which is more photoactive than the tetragonal BiVO4 phase, was obtained by optimizing the power density supplied to the Bi2O3 target, i.e., by tuning the Bi:V:O atomic ratio. The best PEC performance was obtained for a stoichiometric 1:1 Bi:V atomic ratio, attained with 20 W power supplied at the Bi2O3 target and 300 W power supplied at the vanadium target, and an optimal 200 nm thickness of the BiVO4 film, with a 0.65 mA/cm2 photocurrent density attained at 1.23 V vs. standard calomel electrode, under simulated solar light. These results show the suitability of plasma reactive sputtering with two RF powered electrodes for the deposition of BiVO4 photoanodes for water splitting

    A pilot-plant for the selective recovery of magnesium and calcium from waste brines

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    The problem of brines disposal has raised great interest towards new strategies for their valorisation through the recovery of minerals or energy. As an example, the spent brine from ion exchange resins regeneration is often discharged into rivers or lakes, thus impacting on the process sustainability. However, such brines can be effectively reconcentrated, after removal of bivalent cations, and reused for the resins regeneration. This work focuses on developing and testing a pilot plant for selective recovery of magnesium and calcium from spent brines exploiting a novel proprietary crystallization unit. This is part of a larger treatment chain for the complete regeneration of the brine, developed within the EU-funded ZERO BRINE project. The pilot crystallizer was tested with the retentate of the nanofiltration unit processing the spent brine from the industrial water production plant of Evides Industriewater B.V. (Rotterdam, The Netherlands). Magnesium and calcium hydroxide were selectively precipitated by adding alkaline solution in two consecutive steps and controlling reaction pH. Performance was assessed in terms of recovery efficiency and purity of produced crystals, observing in most investigated cases a recovery of about 100% and 97% and a purity above 90% and 96%, for magnesium and calcium hydroxide, respectively

    Use of ecological indices to assess the health status of Posidonia oceanica meadows in Eastern Liguria.

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    Posidonia oceanica (L.) Delile is an endemic Mediterranean seagrass and a key species of coastal marine ecosystems listed among the priority habitats in the European Directive 92/43 / EEC. P. oceanica is a good biological indicator to define the quality of coastal marine ecosystem, because its high sensitivity to environmental conditions changes. The aim of this study is 1) to investigate if the health status of some P.oceanica meadows located in different sites influences the ability of the system to stock natural capital and 2) to quantify changes in natural capital value in both biophysical and monetary terms. Health status of five different meadows along Liguria coast was evaluated by means of different indicators such as: Conservation Index, Substitution Index, Phase Shift Index and Posidonia Rapid Easy Index. Natural capital has been assessed through emergy analysis, a biophysical approach able to account the resources directly and indirectly used up to reach a certain product or mantain a system. Results showed that healthier meadows are located in marine protected areas or far from main sources of anthropic pressures and that higher values of natural capital is stored in healthy seagrass

    Inferring periodic orbits from spectra of simple shaped micro-lasers

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    Dielectric micro-cavities are widely used as laser resonators and characterizations of their spectra are of interest for various applications. We experimentally investigate micro-lasers of simple shapes (Fabry-Perot, square, pentagon, and disk). Their lasing spectra consist mainly of almost equidistant peaks and the distance between peaks reveals the length of a quantized periodic orbit. To measure this length with a good precision, it is necessary to take into account different sources of refractive index dispersion. Our experimental and numerical results agree with the superscar model describing the formation of long-lived states in polygonal cavities. The limitations of the two-dimensional approximation are briefly discussed in connection with micro-disks.Comment: 13 pages, 19 figures, accepted for publication in Physical Review

    Bioactive Limonoids from the Leaves of Azaridachta indica (Neem)

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    Eight new limonoids (1−8) and one new phenol glycoside (9), along with six known compounds, were isolated from the leaves of Azaridachta indica. The structures of 1−9 were elucidated on the basis of spectroscopic data analysis. Compounds isolated were assayed for their cytotoxicity against different cancer cell lines. Moreover, their ability to interact with the molecular chaperone Hsp90, affecting its biological activity, was tested
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