132 research outputs found

    Influence of Short Carbon-Chain Alcohol (Ethanol and 1-Propanol)/Diesel Fuel Blends over Diesel Engine Emissions

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    Oxygenated fuels, in this case short carbon-chain alcohols, have been investigated as alternative fuels to power compression ignition engines. A major advantage of short-chain alcohols is that they can be produced from renewable resources, i.e., cultivated commodities or biomass-based biorefineries. However, before entering the market, the effects of short-chain alcohols on engine performance, exhaust emissions, noise and sound quality need to be understood. This work sheds light on the relationship between the physicochemical properties of the alcohol/diesel fuel blends (ethanol and 1-propanol) on engine performance, exhaust emissions and, for the first time, on noise and sound quality. It has been demonstrated that when the content of alcohol in blends increased, soot and soluble organic material emissions drastically decreased, mainly due to the increase of oxygen content in the fuel. Reduction in soot emissions combined with higher thermodynamic efficiency of alcohol fuels, with respect to diesel fuel, enable their utilization on compression ignition engines. There is also an improvement in the soot-NOx trade off, leading to large reductions on soot with a small effect on NOx emissions. The oxygen content within the fuel reduces CO and THC emissions at extra-urban driving operation conditions. However, hydrocarbons and CO emissions increased at urban driving conditions, due to the high heat of vaporization of the alcohol fuels which reduces cylinder temperature worsening fuel atomization, vaporization and mixing with air being more significant at lower cylinder temperature conditions (low engine loads and speeds). Similarly, the higher the presence of alcohol in the blend, the higher the noise emitted by the engine due to their low tendency to auto-ignition. The optimization of alcohol quantity and the calibration of engine control parameters (e.g., injection settings) which is out of the scope of this work, will be required to overcome noise emission penalty. Furthermore, under similar alcohol content in the blend (10% v/v), the use of propanol is preferred over ethanol, as it exhibits lower exhaust emissions and better sound quality than ethanol

    A Deep Learning Loss Function Based on the Perceptual Evaluation of the Speech Quality

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    This letter proposes a perceptual metric for speech quality evaluation, which is suitable, as a loss function, for training deep learning methods. This metric, derived from the perceptual evaluation of the speech quality algorithm, is computed in a per-frame basis and from the power spectra of the reference and processed speech signal. Thus, two disturbance terms, which account for distortion once auditory masking and threshold effects are factored in, amend the mean square error (MSE) loss function by introducing perceptual criteria based on human psychoacoustics. The proposed loss function is evaluated for noisy speech enhancement with deep neural networks. Experimental results show that our metric achieves significant gains in speech quality (evaluated using an objective metric and a listening test) when compared to using MSE or other perceptual-based loss functions from the literature.Spanish MINECO/FEDER (Grant Number: TEC2016-80141-P)Spanish Ministry of Education through the National Program FPU (Grant Number: FPU15/04161)NVIDIA Corporation with the donation of a Titan X GP

    Ammonia as hydrogen carrier for transportation ; investigation of the ammonia exhaust gas fuel reforming

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    AbstractIn this paper we show, for the first time, the feasibility of ammonia exhaust gas reforming as a strategy for hydrogen production used in transportation. The application of the reforming process and the impact of the product on diesel combustion and emissions were evaluated. The research was started with an initial study of ammonia autothermal reforming (NH3 – ATR) that combined selective oxidation of ammonia (into nitrogen and water) and ammonia thermal decomposition over a ruthenium catalyst using air as the oxygen source. The air was later replaced by real diesel engine exhaust gas to provide the oxygen needed for the exothermic reactions to raise the temperature and promote the NH3 decomposition. The main parameters varied in the reforming experiments are O2/NH3 ratios, NH3 concentration in feed gas and gas – hourly – space – velocity (GHSV). The O2/NH3 ratio and NH3 concentration were the key factors that dominated both the hydrogen production and the reforming process efficiencies: by applying an O2/NH3 ratio ranged from 0.04 to 0.175, 2.5–3.2 l/min of gaseous H2 production was achieved using a fixed NH3 feed flow of 3 l/min. The reforming reactor products at different concentrations (H2 and unconverted NH3) were then added into a diesel engine intake. The addition of considerably small amount of carbon – free reformate, i.e. represented by 5% of primary diesel replacement, reduced quite effectively the engine carbon emissions including CO2, CO and total hydrocarbons

    La válvula cardiaca de Álvarez

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    [ES] Una válvula de disco para sustitución de la válvula mitral fue diseñada en 1964 por el cirujano cardiovascular español Francisco Alvarez. La prótesis se implantó en España y en Inglaterra hasta 1967. Las complicaciones tromboembólicas surgidas aconsejaron la interrupción de su aplicaciónS

    Evaluation of the screening in current diagnosis of prostatic cancer. New development of urinary biomarkers

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    El cáncer de próstata (CaP) es el tumor maligno no cutáneo más frecuente en el hombre, y supone la segunda causa de muerte por cancer en hombres en EEUU, sólo superado por el cáncer de pulmón. Constituye unos de los problemas sanitarios más importantes en nuestro medio, tanto en términos de morbimortalidad, como de impacto social, económico o sobre la calidad de vida. Sin embargo a pesar de tratarse de un cáncer muy prevalente el screening del cáncer de próstata es aún controvertido. Las principales técnicas utilizadas en la evaluación inicial del cáncer de próstata son el examen digito-rectal, antígeno prostático específico (PSA) sérico, y la ecografía transrectal de próstata. El PSA, es considerado actualmente, el biomarcador más importante para la detección y monitorización del CaP, sin embargo carece de especificidad. Esto ha llevado a la búsqueda de biomarcadores tanto urinarios como en sangre, que supongan una alternativa, para superar esa falta de especificidad. Recientemente se han propuesto una serie de marcadores biológicos alternativos en distintos tipos de tumores, entre los que se encuentra el CaP.Prostate cancer (PCa) tumor is the most common non-cutaneous malignancy in men, and is the second leading cause of cancer death in men in the U.S, exceeded only by lung cancer. It is one of the most important health problems in our environment, both in terms of morbidity and mortality, as social, economic or quality of life. But despite being a highly prevalent cancer screening for prostate cancer remains controversial. The main techniques used in the initial evaluation of prostate cancer are finger-rectal examination, serum prostatic specific antigen (PSA), prostate transrectal ultrasound. The PSA is considered the most important biomarker for the detection and monitoring of prostate cancer, however it lacks specificity. This has led to the search for biomarkers in both urine and blood, which constitute an alternative to overcome this lack of specificity. Have recently proposed a series of alternative biological markers in different types of tumors, including PCa found

    Protumorigenic effects of Snail-expression fibroblasts on colon cancer cells

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    et al.Snail1 is a transcriptional factor that plays an important role in epithelial–mesenchymal transition and in the acquisition of invasive properties by epithelial cells. In colon tumors, Snail1 expression in the stroma correlates with lower specific survival of cancer patients. However, the role(s) of Snail1 expression in stroma and its association with patients' survival have not been determined. We used human primary carcinoma-associated fibroblasts (CAFs) or normal fibroblasts (NFs) and fibroblast cell lines to analyze the effects of Snail1 expression on the protumorigenic capabilities in colon cancer cells. Snail1 expression was higher in CAFs than in NFs and, as well as α-SMA, a classic marker of activated CAFs. Moreover, in tumor samples from 50 colon cancer patients, SNAI1 expression was associated with expression of other CAF markers, such as α-SMA and fibroblast activation protein. Interestingly, coculture of CAFs with colon cells induced a significant increase in epithelial cell migration and proliferation, which was associated with endogenous SNAI1 expression levels. Ectopic manipulation of Snail1 in fibroblasts demonstrated that Snail1 expression controlled migration as well as proliferation of cocultured colon cancer cells in a paracrine manner. Furthermore, expression of Snail1 in fibroblasts was required for the coadjuvant effect of these cells on colon cancer cell growth and invasion when coxenografted in nude mice. Finally, cytokine profile changes, particularly MCP-3 expression, in fibroblasts are put forward as mediators of Snail1-derived effects on colon tumor cell migration. In summary, these studies demonstrate that Snail1 is necessary for the protumorigenic effects of fibroblasts on colon cancer cells.This research was supported by the PI12/02037, Fundación Científica AECC, SAF2010-20750, S2010/BMD-2344, RTICC-RD12/0036/0041 and by the Fundación Banco Santander. Antonio García de Herreros’ laboratory was supported by RTICC-RD12/0036/0005 and SAF 2010-16089. Ma Jesús Larriba’s laboratory was supported by RD12/0036/0021. Cristina Peña and José Miguel García are recipients of Miguel Servet Contracts from the Instituto de Salud Carlos III.Peer reviewe

    Trasplante cardíaco

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    A heart transplant is at present considered the treatment of choice in cases of terminal cardiac insufficiency refractory to medical or surgical treatment. Due to factors such as the greater life expectancy of the population and the more efficient management of acute coronary syndromes, there is an increasing number of people who suffer from heart failure. It is estimated that the prevalence of the disease in developed countries is around 1%; of this figure, some 10% are in an advanced stage and are thus potential receptors of a heart transplant. The problem is that it is still not possible to offer this therapeutic form to all of the patients that require it. Consequently, it is necessary to optimise the results of the heart transplant through the selection of patients, selection and management of donors, perioperative management and control of the disease due to graft rejection. Since the first transplant carried out in 1967, numerous advances and changes have taken place, which has made it possible to increase survival and quality of life of those who have received a new heart. In this article we review the most relevant aspects of the heart transplant and the challenges that are currently faced

    Agreement Between 18F-FDG PET/CT and Whole-Body Magnetic Resonance Compared With Skeletal Survey for Initial Staging and Response at End-of-Treatment Evaluation of Patients With Multiple Myeloma

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    PURPOSE: To compare the agreement between whole-body (WB) magnetic resonance (MR) imaging, 18F-FDG PET/CT, and skeletal survey (SS) in patients with multiple myeloma (MM) for diagnosis, initial staging, response evaluation, and early detection of complications. METHODS: This is a retrospective cohort study including MM patients who were diagnosed, treated, and followed in 2 institutions. These patients were studied with SS, WB-MR, and/or 18F-FDG PET/CT. We studied bone lesions by anatomical locations and analyzed the concordance between SS and a tomographic technique (WB-MR or 18F-FDG PET/CT) and between both tomographic techniques (WB-MR and PET/CT). RESULTS: Forty-four MM patients with a mean age of 62.6 years (range, 38-85 years) were included from January 2012 to February 2016. Whole-body MR and 18F-FDG PET/CT found more lesions than SS in every location except in the skull. Concordance between WB-MR and 18F-FDG PET/CT was either good or excellent in most of the locations and in plasmacytoma studies. However, WB-MR was better than 18F-FDG PET/CT in the study of complications (medullar compression and vascular necrosis). CONCLUSIONS: Our results suggest the study of MM patients should include WB-MR and/or 18F-FDG PET/CT, whereas SS is only useful for the skull. Whole-body MR and 18F-FDG PET/CT are complementary techniques, because both of them show good concordance in almost every location. It is still necessary to individualize the indication of each technique according to patient characteristics.None declare

    Evaluation of alpha 1-antitrypsin and the levels of mRNA expression of matrix metalloproteinase 7, urokinase type plasminogen activator receptor and COX-2 for the diagnosis of colorectal cancer

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    Background Colorectal cancer (CRC) is the second most common cause of death from cancer in both men and women in the majority of developed countries. Molecular tests of blood could potentially provide this ideal screening tool. Aim Our objective was to assess the usefulness of serum markers and mRNA expression levels in the diagnosis of CRC. Methods In a prospective study, we measured mRNA expression levels of 13 markers (carbonic anhydrase, guanylyl cyclase C, plasminogen activator inhibitor, matrix metalloproteinase 7 (MMP7), urokinase-type plasminogen activator receptor (uPAR), urokinase-type plasminogen activator, survivin, tetranectin, vascular endothelial growth factor (VEGF), cytokeratin 20, thymidylate synthase, cyclooxygenase 2 (COX-2), and CD44) and three proteins in serum (alpha 1 antitrypsin, carcinoembryonic antigen (CEA) and activated C3 in 42 patients with CRC and 33 with normal colonoscopy results. Results Alpha 1-antitrypsin was the serum marker that was most useful for CRC diagnosis (1.79±0.25 in the CRC group vs 1.27±0.25 in the control group, P<0.0005). The area under the ROC curve for alpha 1-antitrypsin was 0.88 (0.79-0.96). The mRNA expression levels of five markers were statistically different between CRC cases and controls: those for which the ROC area was over 75% were MMP7 (0.81) and tetranectin (0.80), COX-2 (0.78), uPAR (0.78) and carbonic anhydrase (0.77). The markers which identified early stage CRC (Stages I and II) were alpha 1-antitrypsin, uPAR, COX-2 and MMP7. Conclusions Serum alpha 1-antitrypsin and the levels of mRNA expression of MMP7, COX-2 and uPAR have good diagnostic accuracy for CRC, even in the early stages
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