254 research outputs found

    Preparation and characterisation of titania/hydroxyapatite composite coatings obtained by sol-gel process

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    In the present work a titania network encapsulating a hydroxyapatite particulate phase is proposed as a bioceramic composite coating. The coating on a titanium substrate was produced starting from a sol containing a mixture of titania colloidal particles and hydroxyapatite submicron particles using the dip-coating technique. The microstructure, the morphology and the surface chemical composition of the coating were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Adhesion tests were also performed. These analyses showed that the obtained coating was chemically clean, homogeneous, rough, porous, with a low thickness and well-defined phase composition as well as a good adhesion to the substrate. Copyright © 2001 Elsevier Science Ltd

    Direct femtosecond laser fabrication of superhydrophobic aluminum alloy surfaces with anti-icing properties

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    Ice formation is a serious issue in many fields, from energy to aerospace, compromising the devices' efficiency and security. Superhydrophobicity has been demonstrated to be correlated to the anti-icing properties of surfaces. However, fabricating surfaces with robust water repellence properties also at subzero temperature is still a great challenge. In this work, femtosecond laser (fs-laser) texturing is exploited to produce superhydrophobic surfaces with anti-icing properties on Al2024, an aluminum alloy of great interest in cold environments, in particular for aircraft production. Our textured substrates present self-cleaning properties and robust water repellency at subzero temperatures. Moreover, outstanding anti-icing properties are achieved on the textured surfaces at-20 °C, with water droplets bouncing off the surface before freezing

    Sustainable Production of Stiff and Crystalline Bacterial Cellulose from Orange Peel Extract

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    In this work, a potentially economic and environmentally friendly method for the synthesis of bacterial cellulose (BC) by Gluconacetobacter xylinus from a biomass containing orange peel extract was evaluated. Orange peel extract was used as a culture medium without any hydrolysis treatment, thus speeding up the synthesis procedure. The efficacy of orange peel as a carbon source was compared with that of sucrose. The orange peel extract formed thicker cellulose gels than those formed using sucrose. X-ray diffraction (XRD) revealed both a high crystallinity index and crystallite size of BC nanofibers in samples obtained from orange peel (BC_Orange). Field emission scanning electron microscopy (FE-SEM) revealed a highly densely packed nanofibrous structure (50 nm in diameter). BC_Orange presented a two-fold increase in water holding capacity (WHC), and dynamic mechanical analysis (DMA) showed a 44% increase in storage modulus compared to sucrose derived BC. These results showed that the naturally available carbon sources derived from orange peel extract can be effectively used for BC production. The orange-based culture medium can be considered a profitable alternative to the generation of high-value products in a virtuous circular economy model

    Molecular signature of retinoic acid treatment in acute promyelocytic leukemia

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    Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia characterized by a block of differentiation at the promyelocytic stage. APL patients respond to pharmacological concentrations of all-trans retinoic acid ( RA) and disease remission correlates with terminal differentiation of leukemic blasts. The PML/RAR oncogenic transcription factor is responsible for both the pathogenesis of APL and for its sensitivity to RA. In order to identify physiological targets of RA therapy, we analysed gene expression profiles of RA-treated APL blasts and found 1056 common target genes. Comparing these results to those obtained in RA-treated U937 cell lines revealed that transcriptional response to RA is largely dependent on the expression of PML/RAR. Several genes involved in the control of differentiation and stem cell renewal are early targets of RA regulation, and may be important effectors of RA response. Modulation of chromatin modifying genes was also observed, suggesting that specific structural changes in local chromatin domains may be required to promote RA-mediated differentiation. Computational analysis of upstream genomic regions in RA target genes revealed nonrandom distribution of transcription factor binding sites, indicating that specific transcriptional regulatory complexes may be involved in determining RA response

    Measurements and tests on FBK silicon sensors with an optimized electronic design for a CTA camera

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    In October 2013, the Italian Ministry approved the funding of a Research & Development (R&D) study, within the "Progetto Premiale TElescopi CHErenkov made in Italy (TECHE)", devoted to the development of a demonstrator for a camera for the Cherenkov Telescope Array (CTA) consortium. The demonstrator consists of a sensor plane based on the Silicon Photomultiplier (SiPM) technology and on an electronics designed for signal sampling. Preliminary tests on a matrix of sensors produced by the Fondazione Bruno Kessler (FBK-Trento, Italy) and on electronic prototypes produced by SITAEL S.p.A. will be presented. In particular, we used different designs of the electronics in order to optimize the output signals in terms of tail cancellation. This is crucial for applications where a high background is expected, as for the CTA experiment.Comment: 5 pages, 6 figures; Proceedings of the 10th Workshop on Science with the New Generation of High-Energy Gamma-ray experiments (SciNeGHE) - PoS(Scineghe2014)00

    A Prototype of a New Generation Readout ASIC in 65 nm CMOS for Pixel Detectors at HL-LHC

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    The foreseen High-Luminosity upgrade at the CERN Large Hadron Collider (LHC) will constitute a new frontier for particle physics after year 2024, demanding for the installation of new silicon pixel detectors able to withstand unprecedented track densities and radiation levels in the inner tracking systems of current general-purpose experiments. This paper describes the implementation of a new-generation pixel chip demonstrator using a commercial 65 nm CMOS technology and targeting HL-LHC specifications. It was designed as part of the Italian INFN CHIPIX65 project and in close synergy with the international CERN RD53 collaboration on 65 nm CMOS. The prototype is composed of a matrix of 64×64 pixels with 50 ÎŒm × 50 ÎŒm cells featuring a compact design, low-noise and low-power performance. The pixel array integrates two different analogue front-end architectures working in parallel, one with asynchronous and one with synchronous hit discriminators. Common characteristics are a compact layout able to fit into half the pixel size, low-noise performance (ENC < 100 e− RMS for 50 fF input capacitance), below 5 ÎŒW/pixel power consumption, linear charge measurements up to 30 ke− input charge using Time-over-Threshold (ToT) encoding and leakage current compensation up to 50 nA per pixel. A novel region-based digital architecture has been designed in order to ensure > 99% efficiency for expected 3 GHz/cm2 hit rate, 1 MHz trigger rate and 12.5 ÎŒs trigger latency at HL-LHC. Pixels have been organized into regions of 4×4 cells and a common synthesized logic shared among all pixels provides a centralized memory for latency buffering, performs the trigger matching and handles the local configuration. The simulated particle inefficiency for this architecture is below 0.1% under nominal HL-LHC conditions. All global biases and voltages required by analogue front-ends are generated on-chip using 10-bit programmable DACs. Bias currents and voltages can be monitored by a 12-bit ADC. A bandgap voltage reference circuit provides a stable reference voltage for all these blocks. The readout of triggered data is based on replicated FIFOs placed at the chip periphery. Data are finally sent off-chip with 8b/10b encoding using a high-speed serializer. Triggerless and debug operating modes are also supported. Chip configuration and slow-control are performed through fully-duplex synchronous Serial Peripheral Interface (SPI) master/slave transactions. The I/O interface uses custom-designed JEDEC-compliant SLVS transmitters and receivers. All blocks and analogue front-ends have been silicon-proven during a previous prototyping phase and were demonstrated to be radiation tolerant up to 580 Mrad Total Ionizing Dose (TID) or beyond. The CHIPIX65 demonstrator was submitted for fabrication on July 2016. It was received back from the foundry on October 2016 and preliminary experimental characterizations started

    UTRdb and UTRsite (RELEASE 2010) : a collection of sequences and regulatory motifs of the untranslated regions of eukaryotic mRNAs

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    The 5' and 3' untranslated regions of eukaryotic mRNAs (UTRs) play crucial roles in the post-transcriptional regulation of gene expression through the modulation of nucleo-cytoplasmic mRNA transport, translation efficiency, subcellular localization and message stability. UTRdb is a curated database of 5' and 3' untranslated sequences of eukaryotic mRNAs, derived from several sources of primary data. Experimentally validated functional motifs are annotated and also collated as the UTRsite database where more specific information on the functional motifs and cross-links to interacting regulatory protein are provided. In the current update, the UTR entries have been organized in a gene-centric structure to better visualize and retrieve 5' and 3'UTR variants generated by alternative initiation and termination of transcription and alternative splicing. Experimentally validated miRNA targets and conserved sequence elements are also annotated. The integration of UTRdb with genomic data has allowed the implementation of an efficient annotation system and a powerful retrieval resource for the selection and extraction of specific UTR subsets. All internet resources implemented for retrieval and functional analysis of 5' and 3' untranslated regions of eukaryotic mRNAs are accessible at http://utrdb.ba.itb.cnr.it/

    A Prototype of a New Generation Readout ASIC in 65 nm CMOS for Pixel Detectors at HL-LHC

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    The foreseen High-Luminosity upgrade at the CERN Large Hadron Collider (LHC) will constitute a new frontier for particle physics after year 2024, demanding for the installation of new silicon pixel detectors able to withstand unprecedented track densities and radiation levels in the inner tracking systems of current general-purpose experiments. This paper describes the implementation of a new-generation pixel chip demonstrator using a commercial 65 nm CMOS technology and targeting HL-LHC specifications. It was designed as part of the Italian INFN CHIPIX65 project and in close synergy with the international CERN RD53 collaboration on 65 nm CMOS. The prototype is composed of a matrix of 64×64 pixels with 50 ÎŒm × 50 ÎŒm cells featuring a compact design, low-noise and low-power performance. The pixel array integrates two different analogue front-end architectures working in parallel, one with asynchronous and one with synchronous hit discriminators. Common characteristics are a compact layout able to fit into half the pixel size, low-noise performance (ENC < 100 e− RMS for 50 fF input capacitance), below 5 ÎŒW/pixel power consumption, linear charge measurements up to 30 ke− input charge using Time-over-Threshold (ToT) encoding and leakage current compensation up to 50 nA per pixel. A novel region-based digital architecture has been designed in order to ensure > 99% efficiency for expected 3 GHz/cm2 hit rate, 1 MHz trigger rate and 12.5 ÎŒs trigger latency at HL-LHC. Pixels have been organized into regions of 4×4 cells and a common synthesized logic shared among all pixels provides a centralized memory for latency buffering, performs the trigger matching and handles the local configuration. The simulated particle inefficiency for this architecture is below 0.1% under nominal HL-LHC conditions. All global biases and voltages required by analogue front-ends are generated on-chip using 10-bit programmable DACs. Bias currents and voltages can be monitored by a 12-bit ADC. A bandgap voltage reference circuit provides a stable reference voltage for all these blocks. The readout of triggered data is based on replicated FIFOs placed at the chip periphery. Data are finally sent off-chip with 8b/10b encoding using a high-speed serializer. Triggerless and debug operating modes are also supported. Chip configuration and slow-control are performed through fully-duplex synchronous Serial Peripheral Interface (SPI) master/slave transactions. The I/O interface uses custom-designed JEDEC-compliant SLVS transmitters and receivers. All blocks and analogue front-ends have been silicon-proven during a previous prototyping phase and were demonstrated to be radiation tolerant up to 580 Mrad Total Ionizing Dose (TID) or beyond. The CHIPIX65 demonstrator was submitted for fabrication on July 2016. It was received back from the foundry on October 2016 and preliminary experimental characterizations started

    ASPicDB: a database of annotated transcript and protein variants generated by alternative splicing

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    Alternative splicing is emerging as a major mechanism for the expansion of the transcriptome and proteome diversity, particularly in human and other vertebrates. However, the proportion of alternative transcripts and proteins actually endowed with functional activity is currently highly debated. We present here a new release of ASPicDB which now provides a unique annotation resource of human protein variants generated by alternative splicing. A total of 256 939 protein variants from 17 191 multi-exon genes have been extensively annotated through state of the art machine learning tools providing information of the protein type (globular and transmembrane), localization, presence of PFAM domains, signal peptides, GPI-anchor propeptides, transmembrane and coiled-coil segments. Furthermore, full-length variants can be now specifically selected based on the annotation of CAGE-tags and polyA signal and/or polyA sites, marking transcription initiation and termination sites, respectively. The retrieval can be carried out at gene, transcript, exon, protein or splice site level allowing the selection of data sets fulfilling one or more features settled by the user. The retrieval interface also enables the selection of protein variants showing specific differences in the annotated features. ASPicDB is available at http://www.caspur.it/ASPicDB/

    Results from CHIPIX-FE0, a Small-Scale Prototype of a New Generation Pixel Readout ASIC in 65 nm CMOS for HL-LHC

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    A prototype of a new-generation readout ASIC targeting High-Luminosity (HL) LHC pixel detector upgrades has been designed and fabricated as part of the Italian INFN CHIPIX65 project using a commercial 65 nm CMOS technology. This demonstrator, hereinafter referred to as CHIPIX-FE0, is composed of a matrix of 64 7 64 pixels with 50 \ub5m 7 50 \ub5m pixel size embedding two different architectures of analog front-ends working in parallel. The final layout of the chip was submitted and accepted for fabrication on July 2016. Chips were received back from the foundry on October 2016 and successfully characterized before irradiation. Several irradiation campaigns with X-rays have been accomplished during 2017 at Padova INFN and CERN EP/ESE facilities under different uniformity and temperature conditions up to 630 Mrad Total Ionizing Dose (TID). These studies corfirmed negligible degradation of analog front-ends performance after irradiation. First sample chips have been also bump-bonded to 50 \ub5m 7 50 \ub5m and single readout electrode 25 \ub5m 7 100 \ub5m 3D sensors provided by Trento FBK. This represented a major milestone for the entire CHIPIX65 project, offering to the pixel community the first example of a complete readout chip in 65 nm CMOS technology coupled to such a kind of silicon detectors. Extensive characterizations with laser and radioactive sources have started. This paper briefly summarizes most important pre- and post-irradiation results, along with preliminary results obtained from chips bump-bonded to 3D sensors. Selected components of the CHIPIX65 demonstrator have been finally integrated into the large-scale RD53A prototype submitted at the end of summer 2017 by the CERN RD53 international collaboration on 65 nm CMOS technology
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