Improving the functional properties of (K0.5Na0.5)NbO3 piezoceramics by acceptor doping

ZrO2 and TiO2 modified lead-free (K0.5Na0.5)NbO3 (KNN) piezoelectric ceramics are prepared by a conventional solid-state reaction. The effect of acceptor doping on structural and functional properties is investigated. A decrease in the Curie temperature and an increase in the dielectric constant values are observed when doping. More interestingly, an increase in the coercive field E-c and remanent polarization P-r is observed. The piezoelectric properties are greatly increased when doping with small concentrations dopants. ZrO2 doped ceramic exhibits good piezoelectric properties with piezoelectric coefficient d(33) = 134 pC/N and electromechanical coupling factor k(p) = 35%. It is verified that nonlinearity is significantly reduced. Thus, the creation of complex defects capable of pinning the domain wall motion is enhanced with doping, probably due to the formation of oxygen vacancies. These results strongly suggest that compositional engineering using low concentrations of acceptor doping is a good means of improving the functional properties of KNN lead-free piezoceramic system. (C) 2014 Elsevier Ltd. All rights reserved.Postprint (published version

Validation of a Novel, Sensitive, and Specific Urine-Based Test for Recurrence Surveillance of Patients With Non-Muscle-Invasive Bladder Cancer in a Comprehensive Multicenter Study

Bladder cancer (BC), the most frequent malignancy of the urinary system, is ranked the sixth most prevalent cancer worldwide. Of all newly diagnosed patients with BC, 70–75% will present disease confined to the mucosa or submucosa, the non-muscle-invasive BC (NMIBC) subtype. Of those, approximately 70% will recur after transurethral resection (TUR). Due to high rate of recurrence, patients are submitted to an intensive follow-up program maintained throughout many years, or even throughout life, resulting in an expensive follow-up, with cystoscopy being the most cost-effective procedure for NMIBC screening. Currently, the gold standard procedure for detection and follow-up of NMIBC is based on the association of cystoscopy and urine cytology. As cystoscopy is a very invasive approach, over the years, many different noninvasive assays (both based in serum and urine samples) have been developed in order to search genetic and protein alterations related to the development, progression, and recurrence of BC. TERT promoter mutations and FGFR3 hotspot mutations are the most frequent somatic alterations in BC and constitute the most reliable biomarkers for BC. Based on these, we developed an ultra-sensitive, urine-based assay called Uromonitor®, capable of detecting trace amounts of TERT promoter (c.1-124C > T and c.1-146C > T) and FGFR3 (p.R248C and p.S249C) hotspot mutations, in tumor cells exfoliated to urine samples. Cells present in urine were concentrated by the filtration of urine through filters where tumor cells are trapped and stored until analysis, presenting long-term stability. Detection of the alterations was achieved through a custom-made, robust, and highly sensitive multiplex competitive allele-specific discrimination PCR allowing clear interpretation of results. In this study, we validate a test for NMIBC recurrence detection, using for technical validation a total of 331 urine samples and 41 formalin-fixed paraffin-embedded tissues of the primary tumor and recurrence lesions from a large cluster of urology centers. In the clinical validation, we used 185 samples to assess sensitivity/specificity in the detection of NMIBC recurrence vs. cystoscopy/cytology and in a smaller cohort its potential as a primary diagnostic tool for NMIBC. Our results show this test to be highly sensitive (73.5%) and specific (93.2%) in detecting recurrence of BC in patients under surveillance of NMIBC.This study was supported by FCT (“Portuguese Foundation for Science and Technology”) through a PhD grant to RB (SFRH/ BD/111321/2015). Further funding was obtained from the project “Advancing cancer research: from basic knowledge to application” NORTE-01-0145-FEDER-000029: “Projetos Estruturados de I & D & I,” funded by Norte 2020—Programa Operacional Regional do Norte. This article is a result of the project PTDC/MED-ONC/31438/2017 (The Other Faces of Telomerase: Looking beyond Tumor Immortalization), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), COMPETE 2020—Operacional Programme for Competitiveness and Internationalisation (POCI) and by Portuguese funds through FCT. Further funding by the European Regional Development Fund (ERDF) through the Operational Programme for Competitiveness and Internationalisation— COMPETE 2020, and Portuguese national funds via FCT, under project POCI-01-0145-FEDER-016390:CANCEL STEM

VARIABILIDAD DEL ECOTIPO DE ALFALFA 'TIERRA DE CAMPOS'

La alfalfa es el cultivo forrajero más extendido en la comarca de Tierra de Campos. Se cultiva habitualmente en secano, con aprovechamiento mediante siega para heno y mediante pastoreo de los rebrotes, destinándose parte de superficie a la producción de semilla para uso propio. Esta forma de manejo, en este ambiente, a lo largo de los años, ha originado un tipo de alfalfa conocido con el nombre de 'Tierra de Campos'. La introducción en la comarca de alfalfas flamencas para su multiplicación, junto con un mayor intercambio de semilla han contaminado el ecotipo. Con el presente trabajo se pretende contribuir al estudio de su variabilidad. Se inició en 1992, con una prospección en las zonas más habituales de cultivo de alfalfa en Tierra de Campos, recogiéndose 56 muestras de semilla, que se estudiaron en laboratorio, invernadero y campo; en este caso en dos condiciones diferentes: secano y regadío, a lo largo de tres años. En laboratorio se midió la dureza, el tamaño y el peso de la semilla. En invernadero se recogieron datos de la velocidad de crecimiento en estado de plántula. En campo se evaluó el rebrote, velocidad de crecimiento, color de la flor, fecha de floración y persistencia. Junto con las muestras se sembraron como testigos alfalfas de diferente precocidad, algunas de rebrote tardío, como Europe, y otras de rebrote precoz, como CUF-101. Con los datos recogidos se realizó un análisis Cluster, encontrándose que solo el 62 % de las muestras correspondían a las características del ecotipo 'Tierra de Campos', y que el resto estaban mezcladas o eran de otra procedencia. Finalmente, se ha realizado un análisis discriminante, utilizando los datos de todos los caracteres, para saber cuales de estos pueden identificar mejor al ecotipo, habiendo destacado la persistencia, el rebrote primaveral y la velocidad de crecimiento. Se llegó a la conclusión que el ecotipo 'Tierra de Campos' está bastante contaminado, pues el 38 % de las muestras evaluadas no responden a las características del mismo, siendo necesario intervenir cuanto antes para conservar sus características. Los caracteres que mejor sirven para definir el ecotipo son: rebrote primaveral, velocidad de crecimiento, fecha de floración, ritmo de crecimiento de la plántula y persistenci

CO oxidation on ceria studied by electrochemical impedance spectroscopy

Electrochemical impedance spectroscopy technique has been widely used to analyze the electrical properties of a large number of materials. In this study, the electrical properties of CeO2 pellets under CO oxidation conditions have been analyzed by electrochemical impedance spectroscopy. CeO2 pellets have been prepared by a conventional precipitation method and sintered at low temperature to satisfy a compromise between large surface area and a high relative density of the pellet. The electrical properties of CeO2 have been investigated under different atmosphere conditions such as N2, O2, CO, CO2, or selected combinations. The electrical sensitivity of CeO2 to the surrounding atmosphere allows to follow the catalytic reaction as a function of the CO¿:¿O2 ratio and temperature. The appropriate analysis of the electrical response by electrochemical impedance spectroscopy could open a new insight to monitor the catalytic response and behavior of any catalyst.Peer ReviewedPostprint (author's final draft

Measurements of the W boson mass from e"+e"-#->#W"+W"-#->#lvqq events with the ALEPH detector

The W boson mass is measured directly from the reconstructed invariant mass distribution of the decay products in e"+e"-#->#W"+W"-#->#e#nu#-barqq-bar and e"+e"-#->#W"+W"-#->##mu##nu#-barqq-bar events, recorded by the ALEPH detector at the LEP collider at centre-of-mass energies of #sq root#s = 172 GeV during 1996 and #sq root#s = 183 GeV during 1997. An efficient, pure selection and a new kinematic fit to treat the undetected neutrino correctly are developed. The W boson mass is measured by a direct comparison of the data invariant mass distribution with simulated distributions for various W mass values, which axe obtained by using the CC03 matrix element to reweight a large sample fully simulated at one value for the W mass. The result for the W boson mass from the direct reconstruction of 34 e#nu#-barqq-bar and #mu##nu#-barqq-bar candidates at #sq root#s = 172 GeV is: M_W = 80.54 #+-# 0.47(stat.) #+-# 0.11(syst.) GeV/c"2. With the higher statistics at #sq root#s = 183 GeV, the e#nu#-barqq-bar and #mu##nu#-barqq-bar channels are studied separately and the results for the W boson mass from the direct reconstruction of 94 e#nu#-barqq-bar and 78 #mu##nu#-barqq-bar candidates are: M_W"e"#nu#"-"b"a"r"q"q"-"b"a"r = 80.428 #+-# 0.269(stat.) #+-# 0.043(syst.) GeV/c"2; M_W"#mu##nu#"-"b"a"r"q"q"-"b"a"r = 80.370 #+-# 0.287(stat.) #+-# 0.039(syst.) GeV/c"2. The combination of results at #sq root#s = 172 GeV and #sq root#s = 183 GeV is: M_W = 80.422 #+-# 0.181(stat.) #+-# 0.040(syst.) GeV/c"2. This is compared to other measurements and the Standard Model prediction for the W boson mass of 80.365 #+-# 0.030 GeV/c"2. (author)Available from British Library Document Supply Centre-DSC:DXN028470 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Improving the functional properties of (K0.5Na0.5)NbO3 piezoceramics by acceptor doping

ZrO2 and TiO2 modified lead-free (K0.5Na0.5)NbO3 (KNN) piezoelectric ceramics are prepared by a conventional solid-state reaction. The effect of acceptor doping on structural and functional properties is investigated. A decrease in the Curie temperature and an increase in the dielectric constant values are observed when doping. More interestingly, an increase in the coercive field E-c and remanent polarization P-r is observed. The piezoelectric properties are greatly increased when doping with small concentrations dopants. ZrO2 doped ceramic exhibits good piezoelectric properties with piezoelectric coefficient d(33) = 134 pC/N and electromechanical coupling factor k(p) = 35%. It is verified that nonlinearity is significantly reduced. Thus, the creation of complex defects capable of pinning the domain wall motion is enhanced with doping, probably due to the formation of oxygen vacancies. These results strongly suggest that compositional engineering using low concentrations of acceptor doping is a good means of improving the functional properties of KNN lead-free piezoceramic system. (C) 2014 Elsevier Ltd. All rights reserved

Growth and physical properties of highly oriented La-doped (K,Na)NbO3 ferroelectric thin films

Lead-free (K,Na)NbO3 (KNN) and La doped (K,Na)NbO3 (KNN-La) thin films are grown on SrTiO3 substrates using the chemical solution deposition method. The effect of adding different amounts of Na and K excess (0-20 mol%) is investigated. The results confirm the necessity of adding 20 mol% excess amounts of Na and K precursor solutions in order to avoid the formation of the secondary phase, K4Nb6O17, as confirmed by X-ray diffraction and Raman spectroscopy. Moreover, when adding a 20 mol% of alkaline metal excess, the thin films are highly textured with out-of-plane preferential orientation in the [100] direction of the [100] orientation of the substrate. Doping with lanthanum results in a decrease of the leakage current density at low electric field, and an increase in the dielectric permittivity across the whole temperature range (80-380 K). Although the (100)-oriented KNN and KNN-La films exhibited rounded hysteresis loops, at low temperatures the films show the typical ferroelectric hysteresis loops. (C) 2015 Elsevier B.V. All rights reserved