226 research outputs found

    When self-consistency makes a difference

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    Compound semiconductor power RF and microwave device modeling requires, in many cases, the use of selfconsistent electrothermal equivalent circuits. The slow thermal dynamics and the thermal nonlinearity should be accurately included in the model; otherwise, some response features subtly related to the detailed frequency behavior of the slow thermal dynamics would be inaccurately reproduced or completely distorted. In this contribution we show two examples, concerning current collapse in HBTs and modeling of IMPs in GaN HEMTs. Accurate thermal modeling is proved to be be made compatible with circuit-oriented CAD tools through a proper choice of system-level approximations; in the discussion we exploit a Wiener approach, but of course the strategy should be tailored to the specific problem under consideratio

    Tiny Deep Learning Architectures Enabling Sensor-Near Acoustic Data Processing and Defect Localization

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    The timely diagnosis of defects at their incipient stage of formation is crucial to extending the life-cycle of technical appliances. This is the case of mechanical-related stress, either due to long aging degradation processes (e.g., corrosion) or in-operation forces (e.g., impact events), which might provoke detrimental damage, such as cracks, disbonding or delaminations, most commonly followed by the release of acoustic energy. The localization of these sources can be successfully fulfilled via adoption of acoustic emission (AE)-based inspection techniques through the computation of the time of arrival (ToA), namely the time at which the induced mechanical wave released at the occurrence of the acoustic event arrives to the acquisition unit. However, the accurate estimation of the ToA may be hampered by poor signal-to-noise ratios (SNRs). In these conditions, standard statistical methods typically fail. In this work, two alternative deep learning methods are proposed for ToA retrieval in processing AE signals, namely a dilated convolutional neural network (DilCNN) and a capsule neural network for ToA (CapsToA). These methods have the additional benefit of being portable on resource-constrained microprocessors. Their performance has been extensively studied on both synthetic and experimental data, focusing on the problem of ToA identification for the case of a metallic plate. Results show that the two methods can achieve localization errors which are up to 70% more precise than those yielded by conventional strategies, even when the SNR is severely compromised (i.e., down to 2 dB). Moreover, DilCNN and CapsNet have been implemented in a tiny machine learning environment and then deployed on microcontroller units, showing a negligible loss of performance with respect to offline realizations

    Behavioral modeling of GaN-based power amplifiers: impact of electrothermal feedback on the model accuracy and identification

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    In this article, we discuss the accuracy of behavioral models in simulating the intermodulation distortion (IMD) of microwave GaN-based high-power amplifiers in the presence of strong electrothermal (ET) feedback. Exploiting an accurate self-consistent ET model derived from measurements and thermal finite-element method simulations, we show that behavioral models are able to yield accurate results, provided that the model identification is carried out with signals with wide bandwidth and large dynamics

    When self-consistency makes a difference

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    Compound semiconductor power RF and microwave device modeling requires, in many cases, the use of selfconsistent electrothermal equivalent circuits. The slow thermal dynamics and the thermal nonlinearity should be accurately included in the model; otherwise, some response features subtly related to the detailed frequency behavior of the slow thermal dynamics would be inaccurately reproduced or completely distorted. In this contribution we show two examples, concerning current collapse in HBTs and modeling of IMPs in GaN HEMTs. Accurate thermal modeling is proved to be be made compatible with circuit-oriented CAD tools through a proper choice of system-level approximations; in the discussion we exploit a Wiener approach, but of course the strategy should be tailored to the specific problem under consideration

    Metastases risk in thin cutaneous melanoma: Prognostic value of clinical-pathologic characteristics and mutation profile

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    Background: A high percentage of patients with thin melanoma (TM), defined as lesions with Breslow thickness ≤1 mm, presents excellent long-term survival, however, some patients develop metastases. Existing prognostic factors cannot reliably differentiate TM patients at risk for metastases. Objective: We aimed at characterizing the clinical-pathologic and mutation profile of metastatic and not-metastatic TM in order to distinguish lesions at risk of metastases. Methods: Clinical-pathologic characteristics were recorded for the TM cases analyzed. We used a Next Generation Sequencing (NGS) multi-gene panel to characterize TM for multiple somatic mutations. Results: A statistically significant association emerged between the presence of metastases and Breslow thickness ≥0.6 mm (p=0.003). None of TM with lymph-node involvement had Breslow thickness < 0.6 mm. Somatic mutations were identified in 19 of 21 TM analyzed (90.5%). No mutations were observed in two not-metastatic cases with the lowest Breslow thickness (≤0.4 mm), whereas mutations in more than one gene were detected in one metastatic case with the highest Breslow thickness (1.00 mm). Conclusion: Our study indicates Breslow thickness ≥0.6 mm as a valid prognostic factor to distinguish TM at risk for metastases

    Cancer Related Anemia: An Integrated Multitarget Approach and Lifestyle Interventions

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    Cancer is often accompanied by worsening of the patient's iron profile, and the resulting anemia could be a factor that negatively impacts antineoplastic treatment efficacy and patient survival. The first line of therapy is usually based on oral or intravenous iron supplementation; however, many patients remain anemic and do not respond. The key might lie in the pathogenesis of the anemia itself. Cancer-related anemia (CRA) is characterized by a decreased circulating serum iron concentration and transferrin saturation despite ample iron stores, pointing to a more complex problem related to iron homeostatic regulation and additional factors such as chronic inflammatory status. This review explores our current understanding of iron homeostasis in cancer, shedding light on the modulatory role of hepcidin in intestinal iron absorption, iron recycling, mobilization from liver deposits, and inducible regulators by infections and inflammation. The underlying relationship between CRA and systemic low-grade inflammation will be discussed, and an integrated multitarget approach based on nutrition and exercise to improve iron utilization by reducing low-grade inflammation, modulating the immune response, and supporting antioxidant mechanisms will also be proposed. Indeed, a Mediterranean-based diet, nutritional supplements and exercise are suggested as potential individualized strategies and as a complementary approach to conventional CRA therapy

    The Marcus Caelius Project: a transmedial approach to support cultural communication and educational activities at the Civical Archaeological Museum of Bologna

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    [EN] The project “Marcus Caelius – the Value of Memory” is a 8 minute short animation movie located in the Roman Bologna at the Augustan Age. It originated with the Civical Archaeological Museum of Bologna in collaboration with Cineca VisIT-Lab. The project emploies a well known historical fact (the Battle of Teutoburg) to enable a philological approach within an emotional/narrative process. New philologically accurate reconstructions (i.e archaeological finds hedged in the Museum’s collection) are integrated with 3D historical sets caming form previous Cineca projects. Mixed movie-making techniques, such as Blender rendering, Chroma key and Machinima animation, implemented an ad hoc production pipeline in order to define times and costs which could be supported by a small production.[ES] El proyecto de "Marcus Caelius, el valor de la memoria" es una breve película de animación de 8 minutos ambientada en la Bolonia romana (Bononia) durante el periodo del emperador Augusto, que surge de una iniciativa del Museo Arqueológico de Bolonia, en colaboración con Cineca. Este proyecto, basado en un famoso hecho histórico (la batalla de Teutoburgo), quiere proponer un enfoque filológico dentro de un proceso emocional/narrativo, definiendo una pipeline de producción apropiada (que incluye renderizado de Blender, Chroma key y animación Machinima) para definir tiempo y costes que puedan ser cubiertos por un pequeña producción. Nuevas reconstrucciones filológicamente adecuadas (restos arqueológicos en la Colección del Museo), se integran dentro de sets en 3D que proceden deproyectos anteriores de Cineca.The research leading to these results is partly funded by the EU Community's FP7 ICT under the V-MusT.net Project (Grant Agreement 270404). The publication reflects only the author’s views and the Community is not liable for any use that may be made of the information contained therein. Neither the V-MusT.net consortium as a whole, nor a certain participant of the V-MusT.net consortium, warrant that the information contained in this document is capable of use, nor that use of the information is free from risk, and accepts no liability for loss or damage suffered by any person using this information.Bentini, L.; De Luca, D.; Donati, C.; Giovetti, P.; Guidazzoli, A.; Guidi, F.; Marchesi, M.... (2012). The Marcus Caelius Project: a transmedial approach to support cultural communication and educational activities at the Civical Archaeological Museum of Bologna. Virtual Archaeology Review. 3(7):82-85. https://doi.org/10.4995/var.2012.4393OJS828537ANTINUCCI, F. (2010): Comunicare nel museo. Con DVD. Percorsi Laterza. Laterza.BORGATTI, C. et al. (2004): "Databases and virtual environments: a good match for communicating complex cultural sites". in ACM SIGGRAPH 2004 Educators program (New York, NY, USA, 2004), SIGGRAPH '04, ACM. http://dx.doi.org/10.1145/1186107.1186143DELLI PONTI, Francesca et al. (2011): "A Blender open pipeline for a 3D animated historical short film", in Proceeding of the 12th International Symposium on Virtual Reality, Archaeology and Cultural Heritage - Short and Project Papers, VAST 2011.JUNG, Y. et al. (2011): "X3DOM AS CARRIER OF THE VIRTUAL HERITAGE", International Workshop 3D-ARCH, 4, 2011, Trento.O'REILLY, T. (2003): "The Architecture of Participation", [online] http:// www.oreillynet.com/lpt/wlg/3017 [Consult: 14-04-2012]

    Ex vivo mapping of enhancer networks that define the transcriptional program driving melanoma metastasis

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    : Mortality from vmelanoma is associated with metastatic disease, but the mechanisms leading to spreading of the cancer cells remain obscure. Spatial profiling revealed that melanoma is characterized by a high degree of heterogeneity, which is established by the ability of melanoma cells to switch between different phenotypical stages. This plasticity, likely a heritage from embryonic pathways, accounts for a relevant part of the metastatic potential of these lesions, and requires the rapid and efficient reorganization of the transcriptional landscape of melanoma cells. A large part of the non-coding genome cooperates to control gene expression, specifically through the activity of enhancers (ENHs). In this study, we aimed to identify ex vivo the network of active ENHs and to outline their cooperative interactions in supporting transcriptional adaptation during melanoma metastatic progression. We conducted a genome-wide analysis to map active ENHs distribution in a retrospective cohort of 39 melanoma patients, comparing the profiles obtained in primary (N = 19) and metastatic (N = 20) melanoma lesions. Unsupervised clustering showed that the profile for acetylated histone H3 at lysine 27 (H3K27ac) efficiently segregates lesions into three different clusters corresponding to progressive stages of the disease. We reconstructed the map of super-ENHs (SEs) and cooperative ENHs that associate with metastatic progression in melanoma, which showed that cooperation among regulatory elements is a mandatory requirement for transcriptional plasticity. We also showed that these elements carry out specialized and non-redundant functions, and indicated the existence of a hierarchical organization, with SEs on top as masterminds of the entire transcriptional program and classical ENHs as executors. By providing an innovative vision of how the chromatin landscape of melanoma works during metastatic spreading, our data also point out the need to integrate functional profiling in the analysis of cancer lesions to increase definition and improve interpretation of tumor heterogeneity

    Association of nutritional glycaemic indices with global DNA methylation patterns: results from the Moli-sani cohort

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    Background: High dietary glycaemic index (GI) and load (GL) have been associated with increased risk of various cardiometabolic conditions. Among the molecular potential mechanisms underlying this relationship, DNA methylation has been studied, but a direct link between high GI and/or GL of diet and global DNA methylation levels has not been proved yet. We analyzed the associations between GI and GL and global DNA methylation patterns within an Italian population. Results: Genomic DNA methylation (5mC) and hydroxymethylation (5hmC) levels were measured in 1080 buffy coat samples from participants of the Moli-sani study (mean(SD) = 54.9(11.5) years; 52% women) via ELISA. A 188-item Food Frequency Questionnaire was used to assess food intake and dietary GI and GL for each participant were calculated. Multiple linear regressions were used to investigate the associations between dietary GI and GL and global 5mC and 5hmC levels, as well as the proportion of effect explained by metabolic and inflammatory markers. We found negative associations of GI with both 5mC (β (SE) = - 0.073 (0.027), p = 0.007) and 5hmC (- 0.084 (0.030), p = 0.006), and of GL with 5mC (- 0.14 (0.060), p = 0.014). Circulating biomarkers did not explain the above-mentioned associations. Gender interaction analyses revealed a significant association of the gender-x-GL interaction with 5mC levels, with men showing an inverse association three times as negative as in women (interaction β (SE) = - 0.16 (0.06), p = 0.005). Conclusions: Our findings suggest that global DNA methylation and hydroxymethylation patterns represent a biomarker of carbohydrate intake. Based on the differential association of GL with 5mC between men and women, further gender-based separate approaches are warranted
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