566 research outputs found

    A sub-150-nanometre-thick and ultraconformable solution-processed all-organic transistor

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    Recent advancements in the field of electronics have paved the way to the development of new applications, such as tattoo electronics, where the employment of ultraconformable devices is required, typically achievable with a significant reduction in their total thickness. Organic materials can be considered enablers, owing to the possibility of depositing films with thicknesses at the nanometric scale, even from solution. However, available processes do not allow obtaining devices with thicknesses below hundreds of nanometres, thus setting a limit. Here, we show an all-organic field effect transistor that is less than 150 nm thick and that is fabricated through a fully solution-based approach. Such unprecedented thickness permits the device to conformally adhere onto nonplanar surfaces, such as human skin, and to be bent to a radius lower than 1 μm, thereby overcoming another limitation for field-effect transistors and representing a fundamental advancement in the field of ultrathin and tattoo electronics

    Deoxynivalenol content in italian organic durum wheat: Results of a six-year survey

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    Deoxynivalenol (DON) contamination was investigated of Italian durum wheat from organic agriculture. A number of 661 samples from 13 genotypes were collected within the national organic durum wheat network variety trials during the six-year period between 2007–2012 in five different growing areas across Italy (Northern Italy, Marches, Central Apennines, West-Central Italy, Apulia). Mean temperatures and total rainfalls in April, May and June were collected nearby the study sites. Average DON contamination value along the whole study period was 67 μg/kg, and DON was detected only in 36% of the samples. Noteworthy, 95% of the analyzed grain revealed a DON contamination lower than 334 μg/kg. Maximum allowed DON level for unprocessed durum wheat set by European Union (1750 μg/kg) was exceeded only in four samples (0.6%). The highest mean DON values were detected in Northern Italy (175 μg/kg) and Marches (131 μg/kg). The same was for the percentage of positive samples (80% and 58%, respectively). Lower mean values and percentages of contaminated samples were found in West-Central Italy (22 μg/kg and 29%, respectively), Apennines (3 μg/kg and 8%, respectively) and Apulia (2 μg/kg and 7%, respectively). Statistical analysis (Generalized Linear Model, GLZ) was carried out to highlight the effect of factors like cultivation year, growing area and genotype. It revealed a huge effect of year, growing areas and their interaction, while the effect of genotype resulted significantly but quite less than the other main factors. The effect of the year could be explained by climatic data, which suggested an influence of rainfall and temperature at heading on both DON concentration values and percentage of contaminated samples. Results of this study put in evidence a low DON contamination in Italian organic durum wheat

    Establishing Multiple Chip-to-Chip Orthogonal Free-Space Optical Channels using Programmable Silicon Photonics Meshes

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    Two silicon photonics programmable meshes of Mach-Zehnder interferometers are used to automatically establish chip-to-chip orthogonal free-space communication links. Optimum channels with mutual isolation of more than 30dB are found even in case of a misaligned link or in presence of an obstacle in the path

    Self-Configuring Silicon-Photonic Receiver for Multimode Free Space Channels

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    A self-configuring mesh of silicon Mach-Zehnder Interferometers is employed to receive two spatially overlapped orthogonal beams modulated at 10 Gbit/s. These beams, sharing the same wavelength and state of polarization, are separated with more than 30 dB isolation, and sorted out with no signal degradation

    Multimode Free Space Optical Link Enabled by SiP Integrated Meshes

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    A silicon photonic mesh of tuneable Mach-Zehnder Interferometers (MZIs) is employed to receive two spatially-overlapped Hermite-Gaussian beams modulated at 10 Gbit/s, sharing the same wavelength and state of polarization. The mesh automatically self-configures, separating and sorting the two beams out without any excess loss

    Separating arbitrary free-space beams with an integrated photonic processor

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    Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially with atmospheric turbulence or other scattering or aberrations, the arriving beam shapes may not even be known in advance. We show that such beams can be still separated in the optical domain, and simultaneously detected with negligible cross-talk, even if they share the same wavelength and polarization, and even with unknown arriving beam shapes. The kernel of the adaptive multibeam receiver presented in this work is a programmable integrated photonic processor that is coupled to free-space beams through a two-dimensional array of optical antennas. We demonstrate separation of beam pairs arriving from different directions, with overlapping spatial modes in the same direction, and even with mixing between the beams deliberately added in the path. With the circuit’s optical bandwidth of more than 40 nm, this approach offers an enabling technology for the evolution of FSO from single-beam to multibeam space-division multiplexed systems in a perturbed environment, which has been a game-changing transition in fiber-optic systems

    Preliminary survey on the co-occurrence of DON and T2+HT2 toxins in durum wheat in Italy

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    This study was carried out to determine the co-occurrence of deoxynivalenol (DON) and the sum of T2 and HT2 toxins in durum wheat samples belonging to eight cultivars grown in a national network experimental trials over a three-year period (2011–2013). The effect of several factors (cultivar, year and cultivation area) affecting the occurrence of the two types of mycotoxins and their relationship with several agronomic and grain quality parameters were assayed by statistical analysis (GLZ). The results highlighted the different trend of incidence and contamination rate of the two types of mycotoxins in relation to the cropping year and to the growing examined areas. Year and its interaction with the cultivation area was the most important factor affecting the DON contamination, whereas genotype and its interaction with the year mainly influenced T2+HT2 toxins contamination rate. DON and T2+HT2 contamination levels were not significantly correlated with each other. The evidence that the two types of mycotoxins were differently related with several agronomic and grain quality parameters could be connected to the effects of the respective fungal disease on wheat plant

    Choroidal abnormalities detected by near-infrared reflectance imaging as a new diagnostic criterion for neurofibromatosis 1

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    Objective: To investigate in a large sample of consecutive patients with neurofibromatosis type 1 (NF1) the possibility of including the presence of choroidal abnormalities detected by near-infrared reflectance (NIR) as a new diagnostic criterion for NF1. Design: Cross-sectional evaluation of a diagnostic test. Participants and Controls: Ninety-five consecutive adult and pediatric patients (190 eyes) with NF1, diagnosed based on the National Institutes of Health (NIH) criteria. Controls included 100 healthy age- and gender-matched control subjects. Methods: Confocal scanning laser ophthalmoscopy was performed for each subject, investigating the presence and the number of choroidal abnormalities. Main Outcome Measures: Sensitivity, specificity, and diagnostic accuracy for the different cutoff values of the criterion choroidal nodules detected by NIR compared with the NIH criteria. Results: Choroidal nodules detected by NIR imaging were present in 79 (82%) of 95 of the NF1 patients, including 15 (71%) of the 21 NF1 pediatric patients. Similar abnormalities were present in 7 (7%) of 100 healthy subjects, including 2 (8%) of the 25 healthy pediatric subjects. The highest accuracy was obtained at the cutoff value of 1.5 choroidal nodules detected by NIR imagery. Sensitivity and specificity of the examination at the optimal cutoff point were 83% and 96%, respectively. Diagnostic accuracy was 90% in the overall population and 83% in the pediatric population. Both of these values were in line with the most common NIH diagnostic criteria. Conclusions: Choroidal abnormalities appearing as bright patchy nodules detected by NIR imaging frequently occurred in NF1 patients. The present study shows that NIR examination to detect choroidal involvement should be considered as a new diagnostic criterion for NF1
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