217 research outputs found

    Magnetic multiwalled carbon nanotubes as nanocarrier tags for sensitive determination of fetuin in saliva

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    This paper reports the development and performance of an electrochemical immunosensor using magnetic multiwalled carbon nanotubes (m-MWCNTs) as nanocarrier tags for the determination of human fetuin A (HFA), a relevant biomarker of obesity, insulin resistance, and type-2 diabetes as well as for pancreatic and liver cancers and inflammatory processes. Screen-printed carbon electrodes were grafted with p-aminobezoic acid and streptavidin was covalently immobilized on the electrode surface. A biotinylated capture antibody was immobilized through streptavidin-biotin interaction and a sandwich assay configuration was implemented using m-MWCNTs conjugated with HRP and anti-HFA antibodies as the detection label. The determination of HFA was accomplished by measuring the current produced by the electrochemical reduction of benzoquinone at -200 mV upon addition of H2O2 as HRP substrate. The prepared m-MWCNTs were characterized by SEM, TEM, XRD and EDS. All the steps involved in the immunosensor preparation were monitored by electrochemical impedance spectroscopy and cyclic voltammetry. A linear calibration plot for HFA was found between 20 and 2000 pg/mL with a LOD value of 16 pg/mL. This performance is notably better than that reported for an ELISA kit and a chronoimpedimetric immunosensor. The favorable contribution of m-MWCNTs in comparison with MWCNTs without incorporated magnetic particles to this excellent analytical performance is also highlighted. The immunosensor selectivity against other proteins and potentially interfering compounds was excellent. In addition, the usefulness of the immunosensor was demonstrated by the analysis of HFA in saliva with minimal sample treatment

    Pollutant emissions from Euro 6 light duty vehicle tested under steady state and transient operation on a roller test bench with hydrogenated paraffinic and biodiesel fuels

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    [EN] The effort to implement more environmental-friendly fuels has been enhanced not only by the desire to reduce the greenhouse effects but also for public health issues. This paper studies the effects on pollutant emissions from a light-duty Euro 6 vehicle with four types of fuel: diesel (fossil origin, used as reference), biodiesel (renewable origin), Gas-to-Liquid (fossil origin) and farnesane (renewable origin). Both stationary engine and real-world driving cycles are studied. First, each fuel was tested in stationary modes in a vehicle test-bench and then tested in a realistic driving cycle with the same vehicle. This allows the separation the transient effects of the driving cycle from stationary results. Stationary tests lead to engine emission maps and driving cycle tests allow weighting the importance of each stationary condition during a realistic route. Instantaneous and cumulative CO, THC (total hydrocarbon), NOx and PN (particle number) emissions on route were obtained. The fuel that presented a highest level of emissions at stationary conditions was, for CO, diesel, for THC, diesel, for NOx, biodiesel and for PN, diesel. The behaviour of fuels during the driving cycles, from less pollutant to more pollutant, was: for CO, diesel, farnesane, GTL and biodiesel; for THC, GTL, farnesane, biodiesel, diesel. For NOx, farnesane and diesel (very similar values), GTL and biodiesel; for PN, GTL, biodiesel, farnesane and diesel.The authors would like to thank the funding provided by the Spanish Ministry of Science for RECUPERA project (Ref. RTI2018-095923-B-C21) and infrastructure (Ref. EQC2019-005675-P) , the donation of Farnesane fuel by AMYRIS, the donation of GTL fuel by SASOL and the discount provided by REPSOL in the purchase of diesel and biodiesel fuels.Fernández-Yáñez, P.; Soriano, JA.; Soto, F.; Armas, O.; Pla Moreno, B.; Bermúdez, V. (2022). Pollutant emissions from Euro 6 light duty vehicle tested under steady state and transient operation on a roller test bench with hydrogenated paraffinic and biodiesel fuels. Fuel. 323:1-12. https://doi.org/10.1016/j.fuel.2022.12417311232

    Carta t2 con base en estimadores robustos de los parámetros

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    En la primera etapa de implementación de un sistema de control multivariado, usando la carta T ² de Hotelling con n observaciones históricas individuales, la presencia de outliers distorsiona la estimación de los parámetros del proceso y del límite de control debido al efecto de enmascaramiento. En este trabajo proponemos el uso de estimadores robustos para la construcción del estadístico T ² en esta primera etapa. Se prueba con estimadores MVE (elipsoide de mínimo volumen) y estimadores S biponderados, para el caso p = 2. Los resultados de simulaciones señalan que estos dos procedimientos resultan consistentes en la detección de outliers provenientes de perturbaciones en el vector de medias y de la matriz de varianzas covarianzas, consideradas individual y conjuntamente, con diferentes niveles de contaminación.In Phase I, Stage 1 of a multivariate process control, the implementation of a Hotelling's T ² chart with n individual observation, outliers cause difficulties with the estimation of process parameters and control limits due to masking effects. We propose procedures to construct robust estimators based upon the MVE (Minimum Volume Ellipsoide) and the biweighted S estimator, for case p = 2 (Bivariate Process). Simulation results show the good performance of these estimators before outliers presence, avoiding masking effects, when we are estimating the mean vector and varianza covarianza matrix, both individually and jointly. We make the investigation with different levels of contamination affecting the mean vector and varianza covarianza matrix

    Effect of Alloying Elements on Laser Surface Modification of Powder Metallurgy to Improve Surface Mechanical Properties of Beta Titanium Alloys for Biomedical Application

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    [Abstract] Beta-type titanium alloy surfaces (Tie35Nbe10Ta (TNT) and Tie30Nbe4Sn (TNS)) weremodified by laser using a power of 1000 W and speed of 6.7 mm/s (Condition A) and a powerof 1500 W with speed of 10 mm/s (Condition B). Increasing laser conditions, the thicknessof the molten layer was also increased. The initial equiaxed grains changes to quiteelongated grains shape. The surfaces were structured undera00martensite,aand matrixb.Thebphase content decreased slightly and thea00phase increased for both alloysincreasing the laser conditions. The condition A increased the elastic modulus (E) anddecreased the hardness while condition B did not affect the mechanical properties surfacefor the TNT system compared to base metal (BM). In TNS system the laser condition Adecreased the E and increased the hardness while increasing the laser parameters (Con-dition B) both E and hardness decreased compared to BM. The laser surface treatment wasinfluenced by the levels of alloying elements present promoting most significant changesin the microstructure and mechanical properties in the TNS systemThis work was supported by the Ministerio Español de Ciencia, Innovación y Universidades, Spain with Grant RTI2018-097810-B-I00, RTI2018-096472-B-I00 and the European Union (EU) through Fondo Europeo de Desarrollo Regional (FEDER), Spai

    Simulation of Optimal Driving for Minimization of Fuel Consumption or NOx Emissions in a Diesel Vehicle

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    [EN] Significant reduction in fuel consumption and NOx emissions can be achieved just by changing the driving along the road. In this paper, dynamic programming is employed to find two different driving profiles optimized for fuel consumption and NOx creation minimization in a diesel vehicle. Results, show that the fuel reduction driving cycle leads to fuel savings of 4% compared with the average consumption with arbitrary driving. The NOx reduction driving profile improves the emissions of arbitrary driving by a 34.5%. NOx oriented driving profile improves the emissions of the fuel-oriented cycle by a 38% at the expense of a fuel consumption penalty of 10%. This result points out the difficulty of a simultaneous NOx and fuel consumption reduction, stressing the efforts to be done in this field during the following years. Strategies followed and conclusions drawn from this paper are relevant concerning vehicle autonomy integration.This research was funded by the Spanish Ministry of Science and Innovation, grant number RTI2018-095923-B-C21.Fernández-Yáñez, P.; Soriano, JA.; Mata, C.; Armas, O.; Pla Moreno, B.; Bermúdez, V. (2021). Simulation of Optimal Driving for Minimization of Fuel Consumption or NOx Emissions in a Diesel Vehicle. Energies. 14(17):1-15. https://doi.org/10.3390/en14175513S115141

    Combined femoral and tibial component total knee arthroplasty device rotation measurement is reliable and predicts clinical outcome

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    Background The optimal total knee arthroplasty (TKA) rotational alignment and how best to obtain and measure it are debatable. The aim was to analyse the reliability of the Berger femoral, three different tibial and four different com- bined two-dimensional computer tomography (2D-CT) TKA component rotation measurements, and to ascertain which rotational values best predict a successful clinical outcome. Methods The 2D-CT scans were obtained post-operatively on 60 patients who had TKA. We determined one femoral [Berger’s femoral angle (BFA)], three tibial [Berger’s tibial angle (BTA), anatomical tibial angle (ATA) and bimalleolar posterior tibial component angle (BM_PTCA)] and four combined [transepicondylar posterior tibial component angle (TE_PTCA), bicondylar posterior tibial component angle (BC_PTCA, transepicondylar bimalleolar angle (TE_BM) and bicondylar bimalleolar angle (BC_BM)] TKA rotation angles. We made all measures in 23 patients twice by three observers and determined inter- and intra-observer agreement using the Bland–Altman plot method. We analysed measures of 55 patients using the area under the ROC curve (AUC) analysis to ascertain the discriminative capacity of BFA, ATA, TE_PTCA and BC_PTCA for predicting a successful clinical outcome according to the Knee Society Score (KSS) threshold. Results ATA showed the smaller inter- and intra-observer average of differences (-0.1° and 1.6°, respectively) of the studied methods followed by BFA (-0.9° and 1.4°), TE_PTCA (-2.1° and 2.7°) and BC_PTCA (-0.5° and 1.8°). BFA (-4° to 2.1° and -6.1° to 8.8°) and BC_PTCA (-4.4° to 3.4° and -7.9° to 4.4°) showed the narrower inter- and intra- observer limits of agreement. A TKA device rotation (BC_PTCA) < 0.8° of external rotation (ER) predicted a KSS and KSS knee successful outcome, and < 3.8° ER for KSS functional (AUC = 0.889; 0.907 and 0.764, respectively). BFA and ATA < 0.9° ER and < 3.9° internal rotation (IR) predicted a successful KSS knee outcome (AUC = 0.796 and 0.889, respectively). Conclusion The ATA tibial component rotation measurement was the most reliable of those studied. BFA, TE_PTCA and BC_PTCA were reliable measures for TKA femoral and combined rotation. The presence of a minimal rotation between the TKA components (BC_PTCA) and a small femoral ER or tibial IR predicted a successful KSS outcome.Peer ReviewedPostprint (published version

    Interleukin-10 facilitates the selection of patients for systemic thrombolysis

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    Background Clinical-Diffusion mismatch (CDM; NIHSS score ≥8 & DWI lesion volume ≤25 mL) and Perfusion-Diffusion mismatch (PDM; difference >20% between initial DWI and MTT lesion volumes) have been proposed as surrogates for ischemic brains that are at risk of infarction. However, their utility to improve the selection of patients for thrombolytic treatment remains controversial. Our aim was to identify molecular biomarkers that can be used with neuroimaging to facilitate the selection of ischemic stroke patients for systemic thrombolysis. Methods We prospectively studied 595 patients with ischemic stroke within 12 h of the stroke onset. A total of 184 patients received thrombolytic treatment according to the SITS-MOST criteria. DWI and MTT volumes were measured at admission. The main outcome variable was good functional outcome at 3 months (modified Rankin scale <3). Serum levels of glutamate (Glu), IL-10, TNF-α, IL-6, NSE, and active MMP-9 also were determined at admission. Results Patients treated with t-PA who presented with PDM had higher IL-10 levels at admission (p < 0.0001). In contrast, patients with CDM had higher levels of IL-10 (p < 0.0001) as well as Glu and TNF-α (all p < 0.05) and lower levels of NSE and active MMP-9 (all p < 0.0001). IL-10 ≥ 30 pg/mL predicts good functional outcome at 3 months with a specificity of 88% and a sensitibity of 86%. IL-10 levels ≥30 pg/mL independently in both patients with PDM (OR, 18.9) and CDM (OR, 7.5), after an adjustment for covariates. Conclusions Serum levels of IL-10 facilitate the selection of ischemic stroke patients with CDM and PDM for systemic thrombolysis.This project has been partially supported by grants from the Spanish Ministry of Science and Innovation (Fondo de Investigaciones Sanitarias, Instituto Salud Carlos III, RETICS-RD06/0026 and PI081472) and Xunta de Galicia (Consellería de Economía e Industria: 09CSA057918PR, Consellería de Sanidade: PS09/32)S

    Economic evaluation of the primary recovery of tetracycline with traditional and novel aqueous two-phase systems

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    Antibiotics are a key pharmaceutical to inhibit growth or kill microorganisms. They represent a profitable market and, in particular, tetracycline has been listed as an essential medicine by the WHO. Therefore it is important to improve their production processes. Recently novel and traditional aqueous two-phase systems for the extraction have been developed with positive results. The present work performs an economic analysis of the production and recovery of tetracycline through the use of several ATPS through bioprocess modeling using specialized software (BioSolve, Biopharm Services Ltd, UK) to determine production costs per gram (CoG/g). First, a virtual model was constructed using published data on the recovery of tetracycline and extended to incorporate uncertainties. To determine how the model behaved, a sensitivity analysis and Monte Carlo simulations were performed. Results showed that ATPS formed by cholinium chloride/K3PO4 was the best option to recover tetracycline, as it had the lowest CoG/g (US$ 672.83/g), offered the highest recovery yield (92.42%), second best sample input capacity (45% of the ATPS composition) and one of the lowest materials contribution to cost. The ionic liquid-based method of ATPS is a promising alternative for recovering tetracycline from fermentation broth.publishe
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