1,447 research outputs found

    Catalysis-free synthesis of thiazolidine–thiourea ligands for metal coordination (Au and Ag) and preliminary cytotoxic studies

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    The reaction of propargylamines with isothiocyanates results in the selective formation of iminothiazolidines, aminothiazolines or mixed thiazolidine–thiourea compounds under mild conditions. It has been observed that secondary propargylamines lead to the selective formation of cyclic 2-amino-2-thiazoline derivatives, while primary propargylamines form iminothiazoline species. In addition, these cyclic thiazoline derivatives can further react with an excess of isothiocyanate to give rise to thiazolidine–thiourea compounds. These species can also be achieved by reaction of propargylamines with isothiocynates in a molar ratio of 1 : 2. Coordination studies of these heterocyclic species towards silver and gold with different stoichiometries have been carried out and complexes of the type [ML(PPh3)]OTf, [ML2]OTf (M = Ag, Au) or [Au(C6F5)L] have been synthesised. Preliminary studies of the cytotoxic activity in lung cancer cells have also been performed in both ligands and complexes, showing that although the ligands do not exhibit anticancer activity, their coordination to metals, especially silver, greatly enhances the cytotoxic activity

    Formación de heterociclos y compuestos metálicos con aplicaciones biológicas y gelificantes

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    En el capítulo 1 se han sintetizado diferentes compuestos orgánicos cíclicos a través de reacciones entre propargilaminas primarias y secundarias con iso(tio)cianatos. Para estas reacciones, el tipo de amina, la cadena de átomos de carbono, el uso de isocianatos o isotiocianatos y la estequiometría usada son factores muy importantes para conseguir un compuesto final u otro. Así, el uso de un determinado tipo de propargilaminas, daba lugar a la formación de tiazolinas o tiazolidinas, dependiendo de si eran secundarias o primarias, respectivamente. Por otro lado, para estas tiazolidinas formadas se consiguió sintetizar derivados que contuvieran un grupo tiourea en su estructura cuando se modificaba la estequiometría de la reacción. Se estudió la presencia del átomo de oxígeno (isocianato) y azufre (isotiocianato) en diferentes reacciones de ciclación y se utilizaron diversos catalizadores de oro(I) para sintetizar diferentes tiomorfolinas. Finalmente haciéndolas reaccionar con diferentes complejos de oro se consiguió sintetizar diferentes quinolinas en un proceso de ciclación molecular sin precedentes.En el capítulo 2 se sintetizaron nuevos carbenos NHC de oro(I) con diferentes sustituyentes urea con el objetivo de obtener fármacos similares al Auranofin, del que se sabe que tiene excelentes propiedades antitumorales. Inicialmente se sintetizaron nuevas sales de imidazolio con grupos urea, que fueron el producto de partida para la síntesis de carbenos con grupos fosfina o tiolato como ligandos auxiliares, o para la formación de biscarbenos de oro(I). Además, se consiguieron sintetizar por primera vez compuestos bimetálicos de oro, con el ligando actuando de bidentado puente a través de la desprotonación del grupo NH de la urea. Para estos compuestos se midieron sus propiedades anticancerígenas en dos líneas tumorales diferentes (HeLa y A549) y para aquellos compuestos bimetálicos, que presentaban interacciones aurofilicas se estudiaron además sus propiedades luminiscentesEn el capítulo 3, se sintetizaron diferentes escuaramidas, compuestos que se consideran bioesteres de ureas y se coordinaron con los metales del grupo 11, (oro, plata y cobre). Debido a la capacidad de estos compuestos de poder formar diferentes puentes de hidrógeno a través de sus grupos NH, se midieron las propiedades catalíticas, biológicas y su capacidad de gelificación, obteniendo buenos resultados con diferentes disolventes con grupos hidroxilo (alcogeles), aunque fue en disolventes como acetonitrilo y nitrometano donde se obtuvieron las concentraciones más bajas, del orden de 2g∙L-1.<br /

    On the design of Aircraft Electrical Structure Networks

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    As part of the technology research engaged in the EU Clean Sky 1 project, we present in this paper an electrical structure network (ESN) designed to prevent the impact on an electronic equipment of unwanted voltage drops appearing when nonmetal composite materials are used for grounding. An iterative process has been followed to reach an optimal tradeoff solution meeting all the aircraft requirements: structural, safety, low weight, electrical, etc. Guidelines on the design of a low-impedance metal ESN, to minimize the inductive behavior of the power distribution network, are outlined in this paper. To this end, we employ the UGRFDTD simulation tool, combining finite-difference time domain to analyze the general EM problem, and a multiconductor transmission-line network to handle internal coupling between cables running along coinciding routes. The capability of this tool to create time-domain snapshots of surface currents is shown to provide a useful way to optimize the ESN, thanks to the insight gained on the physics of the problem.This work was supported from the European Community Seventh Framework Program FP7/2008-2014 under Grant CSJU-GAM-GRA- 2008-01 (Clean Sky 1 project), and from the Projects TEC2013-48414-C3- 01 and TEC2015-68766-REDC (MINECO, Spain), P12-TIC-1442 (Junta de Andalucia, Spain), Alhambra-UGRFDTD (AIRBUS DS), and by the CSIRC alhambra.ugr.es supercomputing cente

    Narrowband Monolithic Perovskite-Perovskite Tandem Photodetectors

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    Narrowband photodetectors (PDs) are sought after for many applications requiring selective spectral response. The most common systems combine optical bandpass filters with broadband photodiodes. This work reports a method to obtain a narrowband response in a perovskite PD by the monolithic integration of a perovskite photoconductor and a perovskite photodiode. The spectral response of the tandem PD is determined by the bandgap energy difference of the two perovskites, and exhibits a full width at half maximum below 85 nm, an external quantum efficiency up to 68% and a high specific detectivity of ≈1012 Jones in reverse bias, enabling the device to detect weak light signals. The absorption profile of the narrowband PD can be tuned by changing the thickness and bandgap of the wide bandgap perovskite absorber

    The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: tomographic BAO analysis of DR12 combined sample in configuration space

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    We perform a tomographic baryon acoustic oscillations analysis using the two-point galaxy correlation function measured from the combined sample of BOSS DR12, which covers the redshift range of 0.2<z<0.750.2<z<0.75. Splitting the sample into multiple overlapping redshift slices to extract the redshift information of galaxy clustering, we obtain a measurement of DA(z)/rdD_A(z)/r_d and H(z)rdH(z)r_d at nine effective redshifts with the full covariance matrix calibrated using MultiDark-Patchy mock catalogues. Using the reconstructed galaxy catalogues, we obtain the precision of 1.3%2.2%1.3\%-2.2\% for DA(z)/rdD_A(z)/r_d and 2.1%6.0%2.1\%-6.0\% for H(z)rdH(z)r_d. To quantify the gain from the tomographic information, we compare the constraints on the cosmological parameters using our 9-bin BAO measurements, the consensus 3-bin BAO and RSD measurements at three effective redshifts in \citet{Alam2016}, and the non-tomographic (1-bin) BAO measurement at a single effective redshift. Comparing the 9-bin with 1-bin constraint result, it can improve the dark energy Figure of Merit by a factor of 1.24 for the Chevallier-Polarski-Linder parametrisation for equation of state parameter wDEw_{\rm DE}. The errors of w0w_0 and waw_a from 9-bin constraints are slightly improved when compared to the 3-bin constraint result.Comment: 14 pages, 21 figures, 7 Tables. Submitted to MNRA

    Final Stage of Chronic Kidney Disease with Conservative Kidney Management or Renal Replacement Therapy: A Primary-Care Population Study

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    Background: Studies focus on the incidence and risk factors (RFs) associated with reaching the final stage of chronic kidney disease (CKD-G5) and receiving kidney replacement therapy (KRT). Analysis of those related to reaching CKD-G5 while receiving conservative kidney management (CKM) has been neglected. Methods: Retrospective cohort study analysing electronic health records of individuals aged & GE; 50 with eGFR < 60 mL/min/m(2). Cumulative incidence rates of CKD-G5, with and without KRT, were calculated. Multinomial regression models determined odds ratios (ORs) for CKD-G5 progression with KRT, CKM, or death. Results: Among 332,164 patients, the cumulative incidence of CKD-G5 was 2.79 cases per 100 person-years. The rates were 1.92 for CKD-G5 with KRT and 0.87 for CKD-G5 with CKM. Low eGFR and albuminuria were the primary RFs. Male gender and uncontrolled blood pressure had a greater impact on KRT (OR = 2.63 CI, 1.63) than on CKD-G5 with CKM (OR = 1.45 CI, 1.31). Increasing age and rurality reduced the probability of KRT but increased the probability of CKD-G5 with CKM. Higher incomes decreased the likelihood of developing CKD-G5 with and without KRT (OR = 0.49 CI). Conclusion: One-third of CKD-G5 cases receive CKM. Those are typically older, female, rural residents with lower incomes and with lesser proteinuria or cardiovascular RF. The likelihood of receiving KRT is influenced by location and socioeconomic disparities

    The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey : tomographic BAO analysis of DR12 combined sample in Fourier space

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    We perform a tomographic baryon acoustic oscillations (BAO) analysis using the monopole, quadrupole and hexadecapole of the redshift-space galaxy power spectrum measured from the pre-reconstructed combined galaxy sample of the completed Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey (BOSS) Data Release12 covering the redshift range of 0.20 < z < 0.75. By allowing for overlap between neighbouring redshift slices, we successfully obtained the isotropic and anisotropic BAO distance measurements within nine redshift slices to a precision of 1.5–3.4 per cent for DV/rd, 1.8–4.2 per cent for DA/rd and 3.7–7.5 per cent for H rd, depending on effective redshifts. We provide our BAO measurement of DA/rd and H rd with the full covariance matrix, which can be used for cosmological implications. Our measurements are consistent with those presented in Alam et al., in which the BAO distances are measured at three effective redshifts. We constrain dark energy parameters using our measurements and find an improvement of the Figure-of-Merit of dark energy in general due to the temporal BAO information resolved. This paper is a part of a set that analyses the final galaxy clustering data set from BOSS.PostprintPeer reviewe

    Risk factors for graft loss and mortality after renal transplantation according to recipient age: a prospective multicentre study

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    Producción CientíficaBackground. To describe the causes of graft loss, patient death and survival figures in kidney transplant patients in Spain based on the recipient’s age. Methods. The results at 5 years of post-transplant cardiovascular disease (CVD) patients, taken from a database on CVD, were prospectively analysed, i.e. a total of 2600 transplanted patients during 2000–2002 in 14 Spanish renal transplant units, most of them receiving their organ from cadaver donors. Patients were grouped according to the recipient’s age: Group A: 60 years. The most frequent immunosuppressive regimen included tacrolimus, mycophenolate mofetil and steroids. Results. Patients were distributed as follows: 25.85% in Group A (>40 years), 50.9% in Group B (40–60 years) and 23.19% in Group C (>60). The 5-year survival for the different age groups was 97.4, 90.8 and 77.7%, respectively. Death-censored graft survival was 88, 84.2 and 79.1%, respectively, and non death-censored graft survival was 82.1, 80.3 and 64.7%, respectively. Across all age groups, CVD and infections were the most frequent cause of death. The main causes of graft loss were chronic allograft dysfunction in patients 1 g at 6 months post-transplantation were statistically significant in the three age groups. The patient survival multivariate analysis did not achieve a statistically significant common factor in the three age groups. Conclusions. Five-year results show an excellent recipient survival and graft survival, especially in the youngest age group. Death with functioning graft is the leading cause of graft loss in patients >40 years. Early improvement of renal function and proteinuria together with strict control of cardiovascular risk factors are mandatory
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