940 research outputs found

    Rare-earth doped glasses and light managing in solar cells

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    Glasses doped with rare earth elements possess unique photoluminescence properties. They find application in several devices, such as lasers, optical amplifiers, and sensors. More recently, rare-earth doped glass thin films have been the subject of investigation for the development of frequency-converting layers able to increase the efficiency of silicon solar cells. Another approach to the improvement of the performance of a solar cell is based on the capture of a larger flux of light by the detector, which can be obtained by surface texture, plasmonics, or waveguide structures. Here, the recent advances in this area will be briefly reviewed

    prenatal mr imaging detection of deep medullary vein involvement in fetal brain damage

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    SUMMARY: Looking for anomalies distributed in DMV territory, we reviewed 78 fetal MR imaging examinations performed at our institution reporting unequivocal cerebral clastic lesions. We selected 3 cases, all of which had severe cardiocirculatory failure and parenchymal frontoparietal WM hemorrhagic lesions with characteristic fan-shaped distribution. Brain edema and other signs of venous hypertension were also evident. Our data suggest that in utero transient venous hypertension may be responsible for the onset of atypical frontal-located PVL

    Renal Toxicities in Cancer Patients Receiving Immune-Checkpoint Inhibitors: A Meta-Analysis

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    Aim: We performed a meta-analysis of the available clinical trials of immune-checkpoint inhibitors to assess risk differences and relative risks of renal toxicity. Methods: 17 randomized phase III studies were selected, including 10,252 patients. Results: The administration of immune-checkpoint inhibitors resulted in an overall low-grade, high-grade and all-grade renal toxicity Risk Difference of: 0.746% (95% CI 0.629% to 1.15%, p < 0.001—random), 0.61% (95% CI, 0.292–0.929%, p < 0.001—fixed) and 1.2% (95% CI, 0.601–1.85%—random), respectively. The pooled Relative Risk of low-grade, high-grade and all-grade renal toxicity was: 2.185 (95% CI 1.515–3.152—fixed), 2.610 (95% CI, 1.409–4.833, p = 0.002—fixed) and 2.473 (95% CI, 1.782–3.431, p < 0.001—fixed), respectively. An increased risk of renal toxicity was evident in some subgroups more than others. Conclusion: Immune-checkpoint inhibitors are associated with an increased risk of renal toxicity

    Ag-sensitized Tb3+/Yb3+ codoped silica-zirconia glasses and glass-ceramics: Systematic and detailed investigation of the broadband energy-transfer and downconversion processes

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    Abstract Various studies report that Tb3+/Yb3+ co-doped materials can split one UV or 488 nm (visible) photon in two near infrared (NIR) photons at 980 nm by an energy-transfer process involving one Tb3+ and two Yb3+ ions. Additionally, it was demonstrated that Ag multimers can provide an efficient optical sensitizing effect for rare earth ions (RE3+ ions), resulting in a broadband enhanced excitation, which could have a significant technological impact, overcoming their limited spectral absorptions and small excitation cross sections. However, a systematic and detailed investigation of the down-conversion process enhanced by Ag nanoaggregates is still lacking, which is the focus of this paper. Specifically, a step by step analysis of the energy-transfer quantum-cutting chain in Ag-exchanged Tb3+/Yb3+ co-doped glasses and glass-ceramics is presented. Moreover, the direct Ag-Yb3+ energy-transfer is also considered. Results of structural, compositional, and optical characterizations are given, providing quantitative data for the efficient broadband Ag-sensitization of Tb3+/Yb3+ quantum cutting. A deeper understanding of the physical processes beneath the optical properties of the developed materials will allow a wiser realization of more efficient energy-related devices, such as spectral converters for silicon solar cells and light-emitting devices (LEDs) in the visible and NIR spectral regions

    Antibiotic resistance, virulence factors, phenotyping, and genotyping of non\u2013escherichia coli enterobacterales from the gut microbiota of healthy subjects

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    Non-Escherichia coli Enterobacterales (NECE) can colonize the human gut and may present virulence determinants and phenotypes that represent severe heath concerns. Most information is available for virulent NECE strains, isolated from patients with an ongoing infection, while the commensal NECE population of healthy subjects is understudied. In this study, 32 NECE strains were isolated from the feces of 20 healthy adults. 16S rRNA gene sequencing and mass spectrometry attributed the isolates to Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Enterobacter kobei, Citrobacter freundii, Citrobacter amalonaticus, Cronobacter sp., and Hafnia alvei, Morganella morganii, and Serratia liquefaciens. Multiplex PCR revealed that K. pneumoniae harbored virulence genes for adhesins (mrkD, ycfM, and kpn) and enterobactin (entB) and, in one case, also for yersiniabactin (ybtS, irp1, irp2, and fyuA). Virulence genes were less numerous in the other NECE species. Biofilm formation was spread across all the species, while curli and cellulose were mainly produced by Citrobacter and Enterobacter. Among the most common antibiotics, amoxicillin-clavulanic acid was the sole against which resistance was observed, only Klebsiella strains being susceptible. The NECE inhabiting the intestine of healthy subjects have traits that may pose a health threat, taking into account the possibility of horizontal gene transfer

    Shifting sowing of camelina from spring to autumn enhances the oil quality for bio-based applications in response to temperature and seed carbon stock

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    Camelina [Camelina sativa (L.)Crantz]is an emerging oilseed crop that is attracting the interest of farmers in relation to its high environmental adaptability and low-input request. Camelina oil is an outstanding feedstock for the bio-based industry, since its unique composition allows multiple applications. Being spring camelina biotypes able to grow as both an autumn and spring crop in mild climates, and sowing date directly influences the temperature occurring during the seed filling stage, which likewise influences the final seed quality in terms of seed weight, oil and fatty acid (FA)content. A detailed study on the response of spring camelina to the effects of autumn and spring sowing is reported herein. The spring variety Midas was sown at six different sowing dates at the experimental farm of Bologna University (Italy)during two consecutive growing seasons (2015-16 and 2016-17). In parallel, three experiments were also carried out in a growth chamber with different ranges of temperatures during the seed filling period. Samplings of immature seeds over time, in both controlled environment and open field trials, allowed identification of a \u201ctime frame\u201d in which the main variations in FA kinetics occurred. A \u201ccritical period\u201d, from 350 to 540 growing degree day after the start of flowering (GDD-AF)was identified as that in which the closest relation between the final camelina FA composition and temperature, during the seed filling stage, occurred. The adoption of this empirical model permitted early evaluation (about 10 d before harvest)of the final camelina oil composition with relevant implications for the bio-based industry. Autumn sowing dates were associated with increased plant aboveground biomass, seed yield, seed oil content, seed weight (TKW), and content of linolenic and eicosenoic acid. Since eicosenoic acid is a valuable feedstock for the bio-based industry, growing spring camelina, as an autumn crop, in the Mediterranean region allows significantly increase the quantity of this infrequent FA

    FBQS J1644+2619: multiwavelength properties and its place in the class of gamma-ray emitting Narrow Line Seyfert 1s

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    A small fraction of Narrow Line Seyfert 1s (NLSy1s) are observed to be gamma-ray emitters. Understanding the properties of these sources is of interest since the majority of NLSy1s are very different from typical blazars. Here, we present a multi-frequency analysis of FBQS J1644+2619, one of the most recently discovered gamma-ray emitting NLSy1s. We analyse an ~80 ks XMM-Newton observation obtained in 2017, as well as quasi-simultaneous multi-wavelength observations covering the radio - gamma-ray range. The spectral energy distribution of the source is similar to the other gamma-ray NLSy1s, confirming its blazar-like nature. The X-ray spectrum is characterised by a hard photon index (Gamma = 1.66) above 2 keV and a soft excess at lower energies.The hard photon index provides clear evidence that inverse Compton emission from the jet dominates the spectrum, while the soft excess can be explained by a contribution from the underlying Seyfert emission. This contribution can be fitted by reflection of emission from the base of the jet, as well as by Comptonisation in a warm, optically thick corona. We discuss our results in the context of the other gamma-ray NLSy1s and note that the majority of them have similar X-ray spectra, with properties intermediate between blazars and radio-quiet NLSy1s.Comment: Accepted for publication in MNRA

    Antibiotic resistance, virulence factors, phenotyping, and genotyping of non\u2013escherichia coli enterobacterales from the gut microbiota of healthy subjects

    Get PDF
    Non-Escherichia coli Enterobacterales (NECE) can colonize the human gut and may present virulence determinants and phenotypes that represent severe heath concerns. Most information is available for virulent NECE strains, isolated from patients with an ongoing infection, while the commensal NECE population of healthy subjects is understudied. In this study, 32 NECE strains were isolated from the feces of 20 healthy adults. 16S rRNA gene sequencing and mass spectrometry attributed the isolates to Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Enterobacter kobei, Citrobacter freundii, Citrobacter amalonaticus, Cronobacter sp., and Hafnia alvei, Morganella morganii, and Serratia liquefaciens. Multiplex PCR revealed that K. pneumoniae harbored virulence genes for adhesins (mrkD, ycfM, and kpn) and enterobactin (entB) and, in one case, also for yersiniabactin (ybtS, irp1, irp2, and fyuA). Virulence genes were less numerous in the other NECE species. Biofilm formation was spread across all the species, while curli and cellulose were mainly produced by Citrobacter and Enterobacter. Among the most common antibiotics, amoxicillin-clavulanic acid was the sole against which resistance was observed, only Klebsiella strains being susceptible. The NECE inhabiting the intestine of healthy subjects have traits that may pose a health threat, taking into account the possibility of horizontal gene transfer
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