469 research outputs found

    Dynamic simulation model of trans-critical carbon dioxide heat pump application for boosting low temperature distribution networks in dwellings

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    This research investigates the role of new hybrid energy system applications for developing a new plant refurbishment strategy to deploy small scale smart energy systems. This work deals with a dynamic simulation of trans-critical carbon dioxide heat pump application for boosting low temperature distribution networks to share heat for dwellings. Heat pumps provide high temperature heat to use the traditional emission systems. The new plant layout consists of an air source heat pump, four trans-critical carbon dioxide heat pumps (CO2-HPs), photovoltaic arrays, and a combined heat and power (CHP) for both domestic hot water production and electricity to partially drive the heat pumps. Furthermore, electric storage devices adoption has been evaluated. That layout has been compared to the traditional one based on separated generation systems using several energy performance indicators. Additionally, a sensitivity analysis on the primary energy saving, primary fossil energy consumptions, renewable energy fraction and renewable heat, with changes in building power to heat ratios, has been carried out. Obtained results highlighted that using the hybrid system with storage device it is possible to get a saving of 50% approximately. Consequently, CO2-HPs and hybrid systems adoption could be a viable option to achieve Near Zero Energy Building (NZEB) qualification

    A Novel Block-based Watermarking Scheme Using the SVD Transform

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    In this paper, a block-based watermarking scheme based on the Singular Value Decomposition (SVD) is proposed. Our watermark, a pseudo-random Gaussian sequence, is embedded by modifying the angles formed by the right singular vectors of each block of the original image. The orthogonality property of the right singular vector matrix is preserved during the embedding process. Several experiments have been carried out to test the performance of the proposed scheme against different attack scenarios. We conclude that the proposed scheme is resistant against common signal processing operations and attacks, while it preserves the quality of the original image

    Diverse Cretaceous larvae reveal the evolutionary and behavioural history of antlions and lacewings

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    Myrmeleontiformia are an ancient group of lacewing insects characterized by predatory larvae with unusual morphologies and behaviours. Mostly soil dwellers with a soft cuticle, their larvae fossilize only as amber inclusions, and thus their fossil record is remarkably sparse. Here, we document a disparate assemblage of myrmeleontiform larvae from the midCretaceous amber (99 Ma) of Myanmar, evidence of a considerable diversification. Our cladistic analysis integrating extant and extinct taxa resolves the fossils as both stem- and crown-groups. Similarities between extinct and extant species permit inferences of larval ethology of the fossil species through statistical correlation analyses with high support, implying that morphological disparity matched behavioural diversity. An improved understanding of the evolutionary history of antlions and relatives supports the conclusion that hunting strategies, such as camouflage and fossoriality, were acquired early within the lineage

    Isolated hepatocytes versus hepatocyte spheroids: in vitro culture of rat hepatocytes.

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    The use of hepatocytes that express liver-specific functions to develop an artificial liver is promising. Unfortunately, the loss of specialized liver functions (dedifferentiation) is still a major problem. Different techniques, such as collagen entrapment, spherical multicellular aggregates (spheroids), and coculture of hepatocytes with extracellular matrix, have been used to improve the performance of hepatocytes in culture. The aim of this study was to compare two different models of hepatocyte isolation in culture: isolated hepatocytes (G1) and hepatocyte spheroids (60% hepatocytes, 40% nonparenchymal cells, and extracellular matrix) (G2). To test functional activity of hepatocytes, both synthetic and metabolic, production of albumin and benzodiazepine transformation into metabolites was tested. G2 showed a high albumin secretion, while a decrease after 15 days of culture in G1 was noted. Diazepam metabolites were higher in G2 than in G1 in all samples, but had statistical significance at days 14 and 21 (p < 0.01). The glycogen content, after 30 days of culture, was very low in G1 (14.2 ± 4.4%), while in G2 it was 72.1 ± 2.6% (p < 0.01). Our study confirms the effectiveness of a culture technique with extracellular matrix and nonparenchymal cells. Maintenance of a prolonged functional activity has been related to restoration of cell polarity and close cell-to-cell contact. We showed that isolated hepatocytes maintain their functional activity for a period significantly reduced, when compared to the hepatocyte spheroids. We confirmed the role of extracellular matrix as a crucial component to promote hepatocyte homeostasis, and the close link between cellular architecture and tissue-specific functions

    Entanglement swapping with photons generated on-demand by a quantum dot

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    Photonic entanglement swapping, the procedure of entangling photons without any direct interaction, is a fundamental test of quantum mechanics and an essential resource to the realization of quantum networks. Probabilistic sources of non-classical light can be used for entanglement swapping, but quantum communication technologies with device-independent functionalities demand for push-button operation that, in principle, can be implemented using single quantum emitters. This, however, turned out to be an extraordinary challenge due to the stringent requirements on the efficiency and purity of generation of entangled states. Here we tackle this challenge and show that pairs of polarization-entangled photons generated on-demand by a GaAs quantum dot can be used to successfully demonstrate all-photonic entanglement swapping. Moreover, we develop a theoretical model that provides quantitative insight on the critical figures of merit for the performance of the swapping procedure. This work shows that solid-state quantum emitters are mature for quantum networking and indicates a path for scaling up.Comment: The first four authors contributed equally to this work. 17 pages, 3 figure

    Beyond cusp anomalous dimension from integrability

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    We study the first sub-leading correction O((lns)0)O((\ln s)^0) to the cusp anomalous dimension in the high spin expansion of finite twist operators in N=4{\cal N}=4 SYM theory. Since this approximation is still governed by a linear integral equation (derived already from the Bethe Ansatz equations in a previous paper), we finalise it better in order to study the weak and strong coupling regimes. In fact, we emphasise how easily the weak coupling expansion can be obtained, confirms the known four loop result and predicts the higher orders. Eventually, we pay particular attention to the strong coupling regime showing agreement and predictions in comparison with string expansion; speculations on the 'universal' part (upon subtracting the collinear anomalous dimension) are brought forward.Comment: Latex versio

    Factors influencing choice of chemotherapy in metastatic colorectal cancer (mCRC)

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    Management of metastatic colorectal cancer requires a multimodal approach and must be performed by an experienced, multidisciplinary expert team. The optimal choice of the individual treatment modality, according to disease localization and extent, tumor biology, and patient clinical characteristics, will be one that can maintain quality of life and long-term survival, and even cure selected patients. This review is an overview of the different therapeutic approaches available in metastatic colorectal cancer, for the purpose of defining personalized therapeutic algorithms according to tumor biology and patient clinical features

    Strong coupling for planar N=4{\cal N}=4 SYM theory: an all-order result

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    We propose a scheme for determining a generalised scaling function, namely the Sudakov factor in a peculiar double scaling limit for high spin and large twist operators belonging to the sl(2)sl(2) sector of planar N=4{\cal N}=4 SYM. In particular, we perform explicitly the all-order computation at strong 't Hooft coupling regarding the first (contribution to the) generalised scaling function. Moreover, we compare our asymptotic results with the numerical solutions finding a very good agreement and evaluate numerically the non-asymptotic contributions. Eventually, we illustrate the agreement and prediction on the string side.Comment: references added, typos corrected; Latex file plus one figur

    531. Computational Pipeline for the Identification of Integration Sites and Novel Method for the Quantification of Clone Sizes in Clonal Tracking Studies

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    Gene-corrected cells in Gene Therapy (GT) treated patients can be tracked in vivo by means of vector integration site (IS) analysis, since each engineered clone becomes univocally and stably marked by an individual IS. As the proper IS identification and quantification is crucial to accurately perform clonal tracking studies, we designed a customizable and tailored pipeline to analyze LAM-PCR amplicons sequenced by Illumina MiSeq/HiSeq technology. The sequencing data are initially processed through a series of quality filters and cleaned from vector and Linker Cassette (LC) sequences with customizable settings. Demultiplexing is then performed according to the recognition of specific barcodes combination used upon library preparation and the sequences are aligned to the reference genome. Importantly, the human genome assembly Hg19 is composed of 93 contigs, among which the mitochondrial genome, unlocalized and unplaced contigs and some alternative haplotypes of chr6. While previous approaches aligned IS sequences only to the standard 24 human chromosomes, using the whole assembled genome allowed improving alignment accuracy and concomitantly increased the amount of detectable ISs. To date, we have processed 28 independent human sample sets retrieving 260,994 ISs from 189,270,566 sequencing reads. Although, sequencing read counts at each IS have been widely used to estimate the relative IS abundance, this method carries inherent accuracy constraints due to the rounds of exponential amplification required by LAM-PCR that might generate unbalances on the original clonal representation. More recently, a method based on genomic sonication has been proposed exploiting shear site counts to tag the number of original fragments belonging to each IS before PCR amplification. However, the number of cells composing a given clone could far exceed the number of fragments of different lengths that can be generated upon fragmentation in proximity of that given IS. This would rapidly saturate the available diversity of shear sites and progressively generate more and more same-site shearing on independent genomes. In order to overcome the described biases and reliably quantify ISs, we designed and tested a new LC encoding random barcodes. The new LC is composed of a known sequence of 29nt used as binding site for the primers upon amplification steps, a 6nt-random barcode, a fixed-anchor sequence of 6nt, a second 6nt-random barcode and a final known sequence of 22nt containing sticky ends for the three main restriction enzymes in use (MluI, HpyCH4IV and AciI). This peculiar design allowed increasing the accuracy of clonal diversity estimation since the fixed-anchor sequence acts as a control for sequencing reliability in the barcode area. The theoretical number of different available barcodes per clone (412=16,777,216) far exceeds the requirements for not saturating the original diversity of the analyzed sample (on average composed by around 50.000 cells). We validated this novel approach by performing assays on serial dilutions of individual clones carrying known ISs. The precision rate obtained was averagely around 99.3%, while the worst error rate reaches at most the 1.86%, confirming the reliability of IS quantification. We successfully applied the barcoded-LC system to the analysis of clinical samples from a Wiskott Aldrich Syndrome GT patient, collecting to date 50,215 barcoded ISs from 94,052,785 sequencing reads

    Enzyme Immobilization on Maghemite Nanoparticles with Improved Catalytic Activity: An Electrochemical Study for Xanthine

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    Generally, enzyme immobilization on nanoparticles leads to nano-conjugates presenting partially preserved, or even absent, biological properties. Notwithstanding, recent research demonstrated that the coupling to nanomaterials can improve the activity of immobilized enzymes. Herein, xanthine oxidase (XO) was immobilized by self-assembly on peculiar naked iron oxide nanoparticles (surface active maghemite nanoparticles, SAMNs). The catalytic activity of the nanostructured conjugate (SAMN@XO) was assessed by optical spectroscopy and compared to the parent enzyme. SAMN@XO revealed improved catalytic features with respect to the parent enzyme and was applied for the electrochemical studies of xanthine. The present example supports the nascent knowledge concerning protein conjugation to nanoparticle as a means for the modulation of biological activity
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