1,083 research outputs found

    Experimental evidence of delocalized states in random dimer superlattices

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    We study the electronic properties of GaAs-AlGaAs superlattices with intentional correlated disorder by means of photoluminescence and vertical dc resistance. The results are compared to those obtained in ordered and uncorrelated disordered superlattices. We report the first experimental evidence that spatial correlations inhibit localization of states in disordered low-dimensional systems, as our previous theoretical calculations suggested, in contrast to the earlier belief that all eigenstates are localized.Comment: 4 pages, 5 figures. Physical Review Letters (in press

    Assessment of “Sugranineteen” Table Grape Maturation Using Destructive and Auto-Fluorescence Methods

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    The optimal harvesting of table grapes is commonly determined based on technological and phenolic indices analyzed over the course of its maturity. The classical techniques used for these analyses are destructive, time-consuming, and work for a limited number of samples that may not represent the heterogeneity of the vineyard. This study aimed to follow the ripening season of table grapes using non-destructive tools as a rapid and accurate alternative for destructive techniques. Grape samples were collected from a Sugranineteen vineyard during the ripening season to measure the basic maturity indices via wet chemistry, and total polyphenols, anthocyanins, and flavonoids were evaluated by spectrophotometry. Fluorescent readings were collected from intact clusters with a portable optical sensor (Multiplex® 3, Force-A, France) that generates indices correlated to different maturity parameters. Results revealed strong relationships between the Multiplex® indices ANTH_RG and FERARI and the skin anthocyanin content, with R2 values equal to 0.9613 and 0.8713, respectively. The NBI_R index was also related to total anthocyanins (R2 = 0.8032), while the SFR_R index was linked to the titratable acidity (R2 = 0.6186), the sugar content (R2 = 0.7954), and to the color index of red grapes (CIRG) (R2 = 0.7835). Results demonstrated that Multiplex® 3 can be applied on intact clusters as an effective non-destructive tool for a rapid estimation of table grapes’ anthocyanin content

    Effects of legume seeds and processing treatment on growth, carcass traits and blood constituents of fattening lambs

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    This study aimed to evaluate the effects of faba bean, white lupin and pea seed when fed as protein supplements on growth performance, carcass characteristics and haematological characteristics of growing lambs. Forty-eight Gentile di Puglia male lambs, weaned at 38 ± 2 days old with an average initial bodyweight of 12.8 ± 0.5 kg, were divided into six homogenous groups. The six dietary treatments were RFB (diet containing raw faba bean seeds); EFB (diet containing extruded faba bean seeds); RL (diet containing raw lupin seeds); EL (diet containing extruded lupin seeds); RP (diet containing raw pea seeds); and EP (diet containing extruded pea seeds). Feeding lupin seeds reduced average daily feed intake compared with the other protein sources. Carcass conformation, loin weight as a percentage of half-carcass weight, and fat weight as a percentage of loin weight improved in the lambs that consumed both EP and RP diets. Extrusion reduced hide weight as a percentage of empty bodyweight and fat weight as a percentage of leg weight. The protein source had a significant effect on glucose and total cholesterol concentrations, albumin, α1-globulin, β-globulin, and γ-globulin percentages and albumin-globulin ratios. The processing treatment decreased total cholesterol concentrations. Thus, feeding the various legumes did not affect growth performance, but only carcass characteristics; changes which may be due to the differences in feed intake. Extrusion also had minor effects, and further work is required to investigate the use of these protein sources, both raw and extruded.Keywords: extrusion, faba bean, haematology, lupin, pea, protein source, slaughter dat

    Wireless resonant energy link for pulse generators implanted in the chest

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    This study investigates the feasibility of using the MedRadio band for wirelessly transmitting power to a rechargeable medical device implanted in the chest. In particular, a wireless energy link operating at 403 MHz and based on an inductive coupling between two planar resonators is considered, and its performance is assessed through simulations and experimental tests. Results show that a maximum value of the measured power transfer efficiency of ~23% is achieved. Furthermore, the possibility of using the link for recharging a lithium-ion battery of a pulse generator implanted in the chest at a depth of 5 mm is discussed, and the compliance with safety regulations is verified. Reported results demonstrate that the proposed link can be used to charge a lithium-ion battery with a capacity up to 7.2 mAh, while inducing a peak of the specific absorption rate averaged over 1 g of tissue < 1.6 W/kg

    Moisture content measurements through TDR: A metrological assessment for industrial applications

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    In this paper a metrological assessment on the accuracy provided by a Time Domain Reflectometry (TDR)-based method for the estimation of moisture content of granular materials is proposed. In particular, comparative moisture content measurements are carried out through two different TDR instruments: an inexpensive portable unit and a high-performance unit. The main goals are first to assess a robust procedure for TDR moisture monitoring (in particular for sand-like materials), and second to provide a deep metrological analysis for minimizing and characterizing error contributions. This feature is particularly important when considering the proposed measurement procedures for industrial applications, where both accuracy and low cost must be guaranteed

    On the use of dielectric spectroscopy for quality control of vegetable oils

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    Quality control of vegetable oils is becoming more stringent, and related laws are being enforced especially for avoiding adulteration. As a result, there is a substantial need for methods of analysis that could provide real-time in-situ monitoring, especially for quality control purposes during production process. In this regard, the present paper investigates the possibility of monitoring qualitative characteristics of vegetable oils through microwave dielectric spectroscopy, which is a highly versatile investigative approach. In particular, the Cole & Cole frequency-domain dielectric parameters are known to be strongly related to the compositional characteristics of various substances. This way, starting from traditional Time Domain Reflectometry measurements performed on oils, the corresponding frequency domain information is retrieved. Successively, through a minimization routine, the Cole & Cole parameters of each considered oil are extrapolated. Results show that different dielectric characteristics can be associated with different oils. It is important to point out that the characteristics of the proposed procedure can be automated and, therefore, it may represent a promising solution for practical monitoring applications

    The impact of peri-natal stress on psychosis risk: Results from the Bo-FEP incidence study

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    Objective: According to the gene-environment interaction model the pathogenesis of psychosis relies on an adverse neuro-socio-developmental pathway. Perinatal stress represents an important risk factor for the development of psychosis because of the increasingly evident interference with socio-neuro-development in the earlier phases of life. We aim to investigate the correlation of perinatal risk factors with the onset of psychosis with a case-control-incidence study. Results: Patients (and their mothers) were eligible if they presented with first-episode psychosis at the Bologna West Community Mental Health Centre (Bo-West CMHC) between 2002 and 2012. The Bo-West CMHC serves a catchment area of about 200,000 people. The controls were recruited in the same catchment area and study period. 42 patients, 26 controls and their mothers were included. We collected the history of peri-natal stress and calculated crude and adjusted Odds Ratios for onset of first-episode psychosis. Adjusted logistic regression showed that psychosis onset was significantly associated with stressful situations during pregnancy, lower level of maternal physical health before or during pregnancy, use of anti-inflammatory drugs during pregnancy, and low level of maternal education. The results of our study suggest that stress during perinatal period increases the risk of developing psychosis

    Overproduction and Characterization of the Bacillus subtilis Anti-sigma Factor FlgM

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    FlgM is an anti-sigma factor of the flagellar-specific sigma (sigma) subunit of RNA polymerase in Bacillus subtilis, and it is responsible of the coupling of late flagellar gene expression to the completion of the hook-basal body structure. We have overproduced the protein in soluble form and characterized it. FlgM forms dimers as shown by gel exclusion chromatography and native polyacrylamide gel electrophoresis and interacts in vitro with the cognate sigmaD factor. The FlgM.sigmaD complex is a stable heterodimer as demonstrated by gel exclusion chromatography, chemical cross-linking, native polyacrylamide gel electrophoresis, and isoelectric focusing. sigmaD belongs to the group of sigma factors able to bind to the promoter sequence even in the absence of core RNA polymerase. The FlgM.sigmaD complex gave a shift in a DNA mobility shift assay with a probe containing a sigmaD-dependent promoter sequence. Limited proteolysis studies indicate the presence of two structural motifs, corresponding to the N- and C-terminal regions, respectively
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