1,711 research outputs found

    On the optimality of individual entangling-probe attacks against BB84 quantum key distribution

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    It is shown that an existing method to study ideal individual attacks on the BB84 QKD protocol using error discard can be adapted to reconciliation with error correction, and that an optimal attack can be explicitly found. Moreover, this attack fills Luetkenhaus bound, independently of whether error positions are leaked to Eve, proving that it is tight. In addition, we clarify why the existence of such optimal attacks is not in contradiction with the established ``old-style'' theory of BB84 individual attacks, as incorrectly suggested recently in a news feature.Comment: 12 pages, 3 figure

    A Novel Extraction Procedure of Contact Characteristic Parameters from Current–Voltage Curves in CdZnTe and CdTe Detectors

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    The estimation of the characteristic parameters of the electrical contacts in CdZnTe and CdTe detectors is related to the identification of the main transport mechanisms dominating the currents. These investigations are typically approached by modelling the current–voltage (I–V) curves with the interfacial layer–thermionic-diffusion (ITD) theory, which incorporates the thermionic emission, diffusion and interfacial layer theories into a single theory. The implementation of the ITD model in measured I–V curves is a critical procedure, requiring dedicated simplifications, several best fitting parameters and the identification of the voltage range where each transport mechanism dominates. In this work, we will present a novel method allowing through a simple procedure the estimation of some characteristic parameters of the metal–semiconductor interface in CdZnTe and CdTe detectors. The barrier height and the effects of the interfacial layer will be evaluated through the application of a new function related to the differentiation of the experimental I–V curves

    Predictors of HER2 gene amplification in immunohistochemistry score 2+ Early Breast Cancer according to 2018 ASCO/CAP guidelines: a single institution analysis.

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    Background: HER2 overexpression occurs in approximately 15-20% of invasive breast cancers (BC). From a pathological point of view HER2 positivity is defined by intense circumferential membrane complete staining in more than 10% of tumour cells in immunohistochemistry (IHC score 3+). When complete circumferential staining is weak to moderate (IHC score 2+) double probe in situ ibridation (ISH) is mandatory to define HER2 status. In 2018 ASCO/CAP guidelines were updated to provide additional guidance in HER2 equivocal cases to allow a greater discrimination between positive and negative cases. Our aim is to find predictors of HER2 positivity among IHC score 2+ early breast cancer specimens analysed according to 2018 ASCO/CAP guidelines. Patients and methods: 253 cases of early BC diagnosed at Modena Cancer Center between November 2013 and August 2017 were identified. Stage, ISH result, hormonal receptor status (HR), proliferation index (MIB1), and histological grade were captured; menopausal status was available too. All IHC score 2+ cases were reclassified according to 2018 ASCO/CAP guidelines. The association between pathological tumour features, clinical characteristics and ISH positivity was assessed using Fisher test. Results: Overall, 25.7% IHC score 2+ BC resulted HER2 amplified in double probe ISH. High tumour grade (G3 vs G1-2) and MIB1 > 20% significantly predict HER2 ISH amplification (p=0,0001). No correlation was found according to HR, stage, or menopausal status. The majority (185; 98.4%) of HER2-ve BC were reclassified as group 5 (HER2/ CEP17 ratio <2 and HER2 copy number <4 signals/cell) except for 3 specimens classified as group 4 (HER2/CEP17 RATIO <2 and HER2 copy number \ub34 but <6 signals/cell). In HER2+ve group the majority (62; 95.3%) specimens were group 1 (HER2/CEP17 RATIO >2 and HER2 copy number =4 signals/cell), no specimen was group 2, and only 3 cases were classified as group 3 (HER2/CEP17 RATIO <2 and HER2 copy number >6 signals/cell). Conclusions: In this IHC score 2+ BC series, reclassification according to 2018 ASCO/CAP guidelines identified only 4.6% group 3 and 1.6% group 4 cases. The routinely assessment of grading and proliferation index could help to predict HER2 amplification in IHC score 2+ samples even if it must not substitute ISH assay in determining eligibility for HER2 targeted therapies

    Tolerance without clonal expansion: Self-antigen-expressing B cells program self-reactive T cells for future deletion

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    B cells have been shown in various animal models to induce immunological tolerance leading to reduced immune responses and protection from autoimmunity. We show that interaction of B cells with naive T cells results in T cell triggering accompanied by the expression of negative costimulatory molecules such as PD-1, CTLA-4, B and T lymphocyte attenuator, and CD5. Following interaction with B cells, T cells were not induced to proliferate, in a process that was dependent on their expression of PD-1 and CTLA-4, but not CD5. In contrast, the T cells became sensitive to Ag-induced cell death. Our results demonstrate that B cells participate in the homeostasis of the immune system by ablation of conventional self-reactive T cells

    Retrospective assessment of inguinal hernia repair in elderly outpatients

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    Background In the last ten years Day Surgery has significantly evolved, due to improvements in surgery and anaesthesia, and the need of reducing long term admission costs [1]. However, is Day Surgery suitable for elderly patients? The aim of this paper is to assess the risk of over 70 year-old outpatients who underwent inguinal hernia repair, and suggest an adequate preoperative pathway

    Laser-induced transient currents in CdZnTe quasi-hemispherical radiation detector

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    Laser-induced transient currents were measured after applying pulsed or direct-current bias to a CdZnTe quasi-hemispherical radiation detector with gold contacts. The temporal evolution of current transients was analyzed to evaluate the dynamics of the space charge formation and its spatial distribution. The observed effects were explained by a model involving hole injection from positively biased contacts. Experimental results were complemented by numerical simulations, which supported the model. This paper discusses how the detected phenomena affect the detector performance and proposes an improved detector design

    Reduced Self-Reactivity of an Autoreactive T Cell After Activation with Cross-reactive Non–Self-Ligand

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    Autoreactive CD4+ T lymphocytes are critical to the induction of autoimmune disease, but because of the degenerate nature of T cell receptor (TCR) activation such receptors also respond to other ligands. Interaction of autoreactive T cells with other non–self-ligands has been shown to activate and expand self-reactive cells and induce autoimmunity. To understand the effect on the autoreactivity of naive cross-reactive T cells of activation with a potent nonself ligand, we have generated a TCR transgenic mouse which expresses a TCR with a broad cross-reactivity to a number of ligands including self-antigen. The activation of naive transgenic recombination activating gene (Rag)2−/− T cells with a potent non–self-ligand did not result in a enhancement of reactivity to self, but made these T cells nonresponsive to the self-ligand and anti-CD3, although they retained a degree of responsiveness to the non–self-ligand. These desensitized cells had many characteristics of anergic T cells. Interleukin (IL)-2 production was selectively reduced compared with interferon (IFN)-γ. p21ras activity was reduced and p38 mitogen-activated protein kinase (MAPK) was relatively spared, consistent with known biochemical characteristics of anergy. Surprisingly, calcium fluxes were also affected and the anergic phenotype could not be reversed by exogenous IL-2. Therefore, activation with a hyperstimulating non–self-ligand changes functional specificity of an autoreactive T cell without altering the TCR. This mechanism may preserve the useful reactivity of peripheral T cells to foreign antigen while eliminating responses to self

    Incomplete Charge Collection at Inter-Pixel Gap in Low-and High-Flux Cadmium Zinc Telluride Pixel Detectors

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    The success of cadmium zinc telluride (CZT) detectors in room-temperature spectroscopic X-ray imaging is now widely accepted. The most common CZT detectors are characterized by enhanced-charge transport properties of electrons, with mobility-lifetime products µeτe > 10−2 cm2/V and µhτh > 10−5 cm2/V. These materials, typically termed low-flux LF-CZT, are successfully used for thick electron-sensing detectors and in low-flux conditions. Recently, new CZT materials with hole mobility-lifetime product enhancements (µhτh > 10−4 cm2/V and µeτe > 10−3 cm2/V) have been fabricated for high-flux measurements (high-flux HF-CZT detectors). In this work, we will present the performance and charge-sharing properties of sub-millimeter CZT pixel detectors based on LF-CZT and HF-CZT crystals. Experimental results from the measurement of energy spectra after charge-sharing addition (CSA) and from 2D X-ray mapping highlight the better charge-collection properties of HF-CZT detectors near the inter-pixel gaps. The successful mitigation of the effects of incomplete charge collection after CSA was also performed through original charge-sharing correction techniques. These activities exist in the framework of international collaboration on the development of energy-resolved X-ray scanners for medical applications and non-destructive testing in the food industry

    Application of the OECT-Based In Vivo Biosensor Bioristor in Fruit Tree Monitoring to Improve Agricultural Sustainability

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    Water scarcity is a major concern in agriculture worldwide. Fruit trees are severely affected by water deprivation in terms of growth, fruit yield, and quality. Plant monitoring combined with efficient irrigation is pivotal to achieve good quality standards and improve agricultural sustainability. This study reports the use of in vivo sensing technology to monitor fruit tree species continuously, in real time and in vivo, through an Organic Electrochemical Transistor (OECT)-based biosensor called Bioristor. The sensor was applied to grapevines, apples, and kiwis, revealing its capability to trace the plant water status for the whole productive cycle. A correlation between the sensor response index (R) and environmental parameters such as air humidity and temperature were recorded for fruit species. The day/night oscillation of the ionic content in the transpiration stream varies during plant growth and fruit maturation and during severe drought stress. Bioristor promptly detected the occurrence of drought stress. The gate current (Igs) trend supports the reduction in the saturation of the system due to the lower water availability. The use of Bioristor-acquired indices can be used to improve precision irrigation techniques according to the real plant needs

    Window-Based Energy Selecting X-ray Imaging and Charge Sharing in Cadmium Zinc Telluride Linear Array Detectors for Contaminant Detection

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    The spectroscopic and imaging performance of energy-resolved photon counting detectors, based on new sub-millimetre boron oxide encapsulated vertical Bridgman cadmium zinc telluride linear arrays, are presented in this work. The activities are in the framework of the AVATAR X project, planning the development of X-ray scanners for contaminant detection in food industry. The detectors, characterized by high spatial (250 µm) and energy (<3 keV) resolution, allow spectral X-ray imaging with interesting image quality improvements. The effects of charge sharing and energy-resolved techniques on contrast-to-noise ratio (CNR) enhancements are investigated. The benefits of a new energy-resolved X-ray imaging approach, termed window-based energy selecting, in the detection of low- and high-density contaminants are also shown
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