61 research outputs found

    Study for the computational resolution of the conservation equations of mass, momentum and energy. Application to different aeronautical and industrial engineering problems

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    The following final degree dissertation composes a study of the computational resolution of the Navier-Stokes equations. The objective of the work is to introduce the student to the field of Computational Fluid Dynamic (CFD) simulations. This is done by creating self-made codes able to solve problems proposed by the Heat and Mass Transfer Technological Center (CTTC) of the Polytechnic University of Catalonia (UPC). The equations of mass, momentum and energy are solved by means of the Finite Volume Method (FVM) with an algorithm based on the Fractional Step Method (FSM) for incompressible fluids. All the codes are self-programmed and verified by the student in C++ language. Emphasis is made in understanding the different theoretical and computational implications of the Navier-Stokes equations. The different problems are chosen specifically to treat as many aspects of the incompressible NavierStokes equations as possible. Their difficulty increases progressively, starting from a simple conduction heat transfer problem and ending in the study of turbulence. The contribution of the convective and diffusive terms is deeply analyzed, firstly by solving a pure diffusion case and then by finding the numerical solution of a general convection-diffusion equation. The Fractional Step Method is employed to solve both internal flow (with forced and natural convection) and external flow (around a square cylinder). Different aspects about turbulence are studied and implemented to the resolution of the Burgers equation and a three-dimensional channel flow. To finalize the work, a proposal for future steps is given in relation to a more advanced research project, based on a deeper study of turbulence models and High Performance Computing (HPC)

    Isorange pairwise orthogonal transform

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    Spectral transforms are tools commonly employed in multi- and hyperspectral data compression to decorrelate images in the spectral domain. The Pairwise Orthogonal Transform (POT) is one such transform that has been specifically devised for resource-constrained contexts like those found on board satellites or airborne sensors. Combining the POT with a 2D coder yields an efficient compressor for multi- and hyperspectral data. However, a drawback of the original POT is that its dynamic range expansion -i.e., the increase in bit depth of transformed images- is not constant, which may cause problems with hardware implementations. Additionally, the dynamic range expansion is often too large to be compatible with the current 2D standard CCSDS 122.0-B-1. This paper introduces the Isorange Pairwise Orthogonal Transform, a derived transform that has a small and limited dynamic range expansion, compatible with CCSDS 122.0-B-1 in almost all scenarios. Experimental results suggest that the proposed transform achieves lossy coding performance close to that of the original transform. For lossless coding, the original POT and the proposed isorange POT achieve virtually the same performance

    Mosaic-Based Color-Transform Optimization for Lossy and Lossy-to-Lossless Compression of Pathology Whole-Slide Images

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    Altres ajuts: This work has been funded by the EU Marie Curie CIG Programme under Grant PIMCO, the Engineering and Physical Sciences Research Council (EPSRC), UKThe use of whole-slide images (WSIs) in pathology entails stringent storage and transmission requirements because of their huge dimensions. Therefore, image compression is an essential tool to enable efficient access to these data. In particular, color transforms are needed to exploit the very high degree of inter-component correlation and obtain competitive compression performance. Even though the state-of-the-art color transforms remove some redundancy, they disregard important details of the compression algorithm applied after the transform. Therefore, their coding performance is not optimal. We propose an optimization method called mosaic optimization for designing irreversible and reversible color transforms simultaneously optimized for any given WSI and the subsequent compression algorithm. Mosaic optimization is designed to attain reasonable computational complexity and enable continuous scanner operation. Exhaustive experimental results indicate that, for JPEG 2000 at identical compression ratios, the optimized transforms yield images more similar to the original than the other state-of-the-art transforms. Specifically, irreversible optimized transforms outperform the Karhunen-Loève Transform in terms of PSNR (up to 1.1 dB), the HDR-VDP-2 visual distortion metric (up to 3.8 dB), and the accuracy of computer-aided nuclei detection tasks (F1 score up to 0.04 higher). In addition, reversible optimized transforms achieve PSNR, HDR-VDP-2, and nuclei detection accuracy gains of up to 0.9 dB, 7.1 dB, and 0.025, respectively, when compared with the reversible color transform in lossy-to-lossless compression regimes

    Porcine Digestible Peptides (PDP) in Weanling Diets Regulates the Expression of Genes Involved in Gut Barrier Function, Immune Response and Nutrient Transport in Nursery Pigs

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    CRAG 10.3390/ani10122368This study was conducted to investigate the effects of dietary supplementation of porcine digestible peptides (PDP), spray-dried plasma (SDP), or a combination of both, on growth performance and the expression of genes related to intestinal function of weaned pigs. A total of 180 piglets (trial 1) and 198 piglets (trial 2) were used to evaluate the partial substitution of soybean ingredients with 2% SDP or 2% PDP (trial 1), and with 3% SDP or the combination of 1% SDP and 2% PDP (SDP-PDP; trial 2) during the pre-starter period (0-14 days). The gene expression of 56 genes was quantified in a qPCR platform in jejunum and ileum samples obtained from piglets 14 d after weaning (trial 2). Piglets fed SDP, PDP and SDP-PDP had a higher body weight (BW), average daily gain (ADG) and feed efficiency (G:F) than the soybean control on day 14 (p < 0.05). In addition, the combination of SDP and PDP upregulated ten genes in jejunum samples (p < 0.05) related to intestinal function. More research is needed to confirm that gene expression upregulation by PDP in combination with SDP has an impact on intestinal function and to elucidate its underlying mechanisms

    ErbBs inhibition by lapatinib blocks tumor growth in an orthotopic model of human testicular germ cell tumor

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    In this work, we have analyzed the expression of different members of the ErbB family in human samples of testicular germ cell tumors (GCTs). We observed expression of ErbB1 or ErbB2 in different tumor subtypes, but we also found high expression of ErbB3 in all GCTs tested. This pattern of expression was maintained when primary tumors were orthotopically implanted in nude mice. We have chosen a choriocarcinoma model characterized by high levels of ErbB1, but also of ErbB2 and ErbB3, to assay the in vivo effect of ErbB inhibitors on tumoral growth. Our results showed a complete lack of effect (refractoriness) to the pure ErbB1 receptor inhibitors cetuximab and gefitinib. While these inhibitors blocked ErbB1 phosphorylation, ErbB2 phosphorylation was not affected, suggesting an ErbB1-independent activation of this receptor. To confirm the importance of ErbB2 activation, animals were treated with lapatinib, a dual ErbB1 and ErbB2 inhibitor. Lapatinib treatment caused a 50% inhibition in tumor growth, an effect correlated with a blockade of both ErbB1 and ErbB2 phosphorylation levels, and of downstream signaling pathways (Akt, ERKs and Stat3). ErbB2 activation could still occur due to the formation of ErbB2/ErbB3 heterodimers, and ErbB3 activation was completely inhibited by lapatinib. Finally, combined inhibition of ErbB1 (gefitinib) and ErbB3 activities (knockdown expression by shRNA) inhibited tumoral testicular cells proliferation in a similar way to lapatinib. Our results explain why lapatinib but not anti-ErbB1 agents might be effective for treatment of testicular GCT patients

    A comprehensive biomarker analysis of microsatellite unstable/mismatch repair deficient colorectal cancer cohort treated with immunotherapy

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    The search for immunotherapy biomarkers in Microsatellite Instability High/Deficient Mismatch Repair system (MSI-H/dMMR) metastatic colorectal cancer (mCRC) is an unmet need. Sixteen patients with mCRC and MSI-H/dMMR (determined by either immunohistochemistry or polymerase chain reaction) treated with PD-1/PD-L1 inhibitors at our institution were included. According to whether the progression-free survival with PD-1/PD-L1 inhibitors was longer than 6 months or shorter, patients were clustered into the IT-responder group (n: 9 patients) or IT-resistant group (n: 7 patients), respectively. In order to evaluate determinants of benefit with PD-1/PD-L1 inhibitors, we performed multimodal analysis including genomics (through NGS panel tumour-only with 431 genes) and the immune microenvironment (using CD3, CD8, FOXP3 and PD-L1 antibodies). The following mutations were more frequent in IT-resistant compared with IT-responder groups: B2M (4/7 versus 2/9), CTNNB1 (2/7 versus 0/9), and biallelic PTEN (3/7 versus 1/9). Biallelic ARID1A mutations were found exclusively in the IT-responder group (4/9 patients). Tumour mutational burden did not correlate with immunotherapy benefit, neither the rate of indels in homopolymeric regions. Of note, biallelic ARID1A mutated tumours had the highest immune infiltration and PD-L1 scores, contrary to tumours with CTNNB1 mutation. Immune microenvironment analysis showed higher densities of different T cell subpopulations and PD-L1 expression in IT-responders. Misdiagnosis of MSI-H/dMMR inferred by discordances between immunohistochemistry and polymerase chain reaction was only found in the IT-resistant population (3/7 patients). Biallelic ARID1A mutations and Wnt signalling activation through CTNNB1 mutation were associated with high and low T cell immune infiltrates, respectively, and deserve special attention as determinants of response to PD-1/PD-L1 inhibitors. The non-MSI-H phenotype in dMMR is associated with poor benefit to immunotherapy. Our results suggest that mechanisms of resistance to immunotherapy are multi-factorial

    Impact of Inflammatory Response Modifiers on the Incidence of Hospital-Acquired Infections in Patients with COVID-19.

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    The study aim was to assess the influence of inflammatory response modifiers, including anti-interleukin-6 (IL-6) biologics and corticosteroids, on the incidence of hospital-acquired infections in patients with coronavirus disease 2019 (COVID-19). METHODS: Case-control study performed at a university hospital from February 26 to May 26, 2020. Cases were defined as patients with COVID-19 who developed hospital-acquired infections. For each case, two controls were selected among patients without infections. Cases and controls were matched obeying three criteria in a hierarchical sequence: length of hospital stay up until the first infection; comorbidity; and need for Intensive care unit (ICU) admission. Conditional logistic regression analysis was used to estimate the association of exposures with being a case. RESULTS: A total of 71 cases and 142 controls were included. Independent predictors for acquiring a hospital infection were chronic liver disease [odds ratio (OR) 16.56, 95% CI 1.87-146.5, p = 0.012], morbid obesity (OR 6.11, 95% CI 1.06-35.4, p = 0.043), current or past smoking (OR 4.15, 95% CI 1.45-11.88, p = 0.008), exposure to hydroxychloroquine (OR 0.2, 95% CI 0.041-1, p = 0.053), and invasive mechanical ventilation (OR 61.5, 95% CI 11.08-341, p ≤ 0.0001). CONCLUSIONS: Inflammatory response modifiers had no influence on acquisition of nosocomial infections in admitted patients with COVID-19. Hospital-acquired infections primarily occurred in the critically ill and invasive mechanical ventilation was the main exposure conferring risk

    Porcine Digestible Peptides (PDP) in Weanling Diets Regulates the Expression of Genes Involved in Gut Barrier Function, Immune Response and Nutrient Transport in Nursery Pigs

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    This study was conducted to investigate the effects of dietary supplementation of porcine digestible peptides (PDP), spray-dried plasma (SDP), or a combination of both, on growth performance and the expression of genes related to intestinal function of weaned pigs. A total of 180 piglets (trial 1) and 198 piglets (trial 2) were used to evaluate the partial substitution of soybean ingredients with 2% SDP or 2% PDP (trial 1), and with 3% SDP or the combination of 1% SDP and 2% PDP (SDP-PDP; trial 2) during the pre-starter period (0-14 days). The gene expression of 56 genes was quantified in a qPCR platform in jejunum and ileum samples obtained from piglets 14 d after weaning (trial 2). Piglets fed SDP, PDP and SDP-PDP had a higher body weight (BW), average daily gain (ADG) and feed efficiency (G:F) than the soybean control on day 14 (p < 0.05). In addition, the combination of SDP and PDP upregulated ten genes in jejunum samples (p < 0.05) related to intestinal function. More research is needed to confirm that gene expression upregulation by PDP in combination with SDP has an impact on intestinal function and to elucidate its underlying mechanisms

    First-line treatment in lymphomatoid papulosis: a retrospective multicentre study

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    Background: Data regarding response to treatment in lymphomatoid papulosis (LyP) are scarce. Aim: To assess the daily clinical practice approach to LyP and the response to first-line treatments. Methods: This was a retrospective study enrolling 252 patients with LyP. Results: Topical steroids, methotrexate and phototherapy were the most common first-line treatments, prescribed for 35%, 20% and 14% of the patients, respectively. Complete response (CR) was achieved in 48% of treated patients. Eczematous lesions significantly increased relative risk (RR) of not achieving CR (RR = 1.76; 95% CI 1.16-2.11). Overall median time to CR was 10 months (95% CI 6-13 months), and 78% of complete responders showed cutaneous relapse; both results were similar for all treatment groups (P > 0.05). Overall estimated median disease-free survival (DFS) was 11 months (95% CI 9-13 months) but DFS for patients treated with phototherapy was 23 months (95% CI 10-36 months; P < 0.03). Having the Type A LyP variant (RR = 2.04; 95% CI 0.96-4.30) and receiving a first-line treatment other than phototherapy (RR = 5.33; 95% CI 0.84-33.89) were significantly associated with cutaneous early relapse. Of the 252 patients, 31 (13%) had associated mycosis fungoides unrelated to therapeutic approach, type of LyP or T-cell receptor clonality. Conclusions: Current epidemiological, clinical and pathological data support previous results. Topical steroids, phototherapy and methotrexate are the most frequently prescribed first-line treatments. Although CR and cutaneous relapse rates do not differ between them, phototherapy achieves a longer DFS. Presence of Type A LyP and use of topical steroid or methotrexate were associated with an increased risk of early relapse

    Characterization, Recombinant Production and Structure-Function Analysis of NvCI, A Picomolar Metallocarboxypeptidase Inhibitor from the Marine Snail Nerita versicolor

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    A very powerful proteinaceous inhibitor of metallocarboxypeptidases has been isolated from the marine snail Nerita versicolor and characterized in depth. The most abundant of four, very similar isoforms, NvCla, was taken as reference and N-terminally sequenced to obtain a 372-nucleotide band coding for the protein cDNA. The mature protein contains 53 residues and three disulphide bonds. NvCIa and the other isoforms show an exceptionally high inhibitory capacity of around 1.8 pM for human Carboxypeptidase A1 (hCPA1) and for other A-like members of the M14 CPA subfamily, whereas a twofold decrease in inhibitory potency is observed for carboxypeptidase B-like members as hCPB and hTAFIa. A recombinant form, rNvCI, was produced in high yield and HPLC, mass spectrometry and spectroscopic analyses by CD and NMR indicated its homogeneous, compact and thermally resistant nature. Using antibodies raised with rNvCI and histochemical analyses, a preferential distribution of the inhibitor in the surface regions of the animal body was observed, particularly nearby the open entrance of the shell and gut, suggesting its involvement in biological defense mechanisms. The properties of this strong, small and stable inhibitor of metallocarboxypeptidases envisage potentialities for its direct applicability, as well as leading or minimized forms, in biotechnological/biomedical uses
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