Mitonafide and Amonafide

La naftalimidas constituyen una familia de nuevos agentes intercalantes con propiedades anticancerosas. En este trabajo, se describe el diseño, la síntesis y la actividad quimioterapéutica, junto a otros estudios preclínicos realizados con vistas a la iniciación de los ensayos clínicos.The naphthalimides are a family of new intercalator agents with antitumor properties. Rere, we describe the design, synthesis and chemotherapeutic activity, together with the results of preclinical studies in order to initiate the clinical essays

Mitonafide and Amonafide

La naftalimidas constituyen una familia de nuevos agentes intercalantes con propiedades anticancerosas. En este trabajo, se describe el diseño, la síntesis y la actividad quimioterapéutica, junto a otros estudios preclínicos realizados con vistas a la iniciación de los ensayos clínicos.The naphthalimides are a family of new intercalator agents with antitumor properties. Rere, we describe the design, synthesis and chemotherapeutic activity, together with the results of preclinical studies in order to initiate the clinical essays

Effects of introgressed 4Nv Aegilops ventricosa chromosome on yield and yield components in bread wheat.

Effects of introgressed 4Nv Aegilops ventricosa chromosome on yield and yield components in bread whea

A novel growth method to improve the quality of GaAs nanowires grown by Ga-assisted chemical beam epitaxy

The successful synthesis of high crystalline quality and high aspect ratio GaAs nanowires (NWs) with a uniform diameter is needed to develop advanced applications beyond the limits established by thin film and bulk material properties. Vertically aligned GaAs NWs have been extensively grown by Ga-assisted vapor–liquid–solid (VLS) mechanism on Si(111) substrates, and they have been used as building blocks in photovoltaics, optoelectronics, electronics, and so forth. However, the nucleation of parasitic species such as traces and nanocrystals on the Si substrate surface during the NW growth could affect significantly the controlled nucleation of those NWs, and therefore the resulting performance of NW-based devices. Preventing the nucleation of parasitic species on the Si substrate is a matter of interest, because they could act as traps for gaseous precursors and/or chemical elements during VLS growth, drastically reducing the maximum length of grown NWs, affecting their morphology and structure, and reducing the NW density along the Si substrate surface. This work presents a novel and easy to develop growth method (i.e., without using advanced nanolithography techniques) to prevent the nucleation of parasitic species, while preserving the quality of GaAs NWs even for long duration growths. GaAs NWs are grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates using triethylgallium and tertiarybutylarsine precursors by a two-step-based growth method presented here; this method includes a growth interruption for an oxidation on air between both steps of growth, reducing the nucleation of parasitic crystals on the thicker SiOx capping layer during the second and longer growth step. VLS conditions are preserved overtime, resulting in a stable NW growth rate of around 6 μm/h for growth times up to 1 h. Resulting GaAs NWs have a high aspect ratio of 85 and average radius of 35 nm. We also report on the existence of characteristic reflection high-energy electron diffraction patterns associated with the epitaxial growth of GaAs NWs on Si(111) substrates, which have been analyzed and compared to the morphological characterization of GaAs NWs grown for different times under different conditions

Photodetector Fabrication by Dielectrophoretic Assembly of GaAs Nanowires Grown by a Two-steps Method

GaAs nanowires (NWs) are promising advanced materials for the development of high performance photodetectors in the visible and infrared range. In this work, we optimize the epitaxial growth of GaAs NWs compared to conventional procedures, by introducing a novel two-steps growth method that exhibits an improvement of the resulting NW aspectratio and an enhancement of the NW growth rate. Moreover, we investigate the contactless manipulation of NWs using non-uniform electric fields to assemble a single GaAs NW on conductive electrodes, resulting in assembly yields above 90%/site and an alignment yields of around 95%. The electrical characteristics of the dielectrophoretic contact formed between the NW and the electrode have been measured, observing that the use of n-type Al-doped ZnO (AZO) as electrode material for NW alignment produces Schottky barrier contacts with the GaAs NW body. Moreover, our results show the fast fabrication of diodes with rectifying characteristics due to the formation of a low-resistance contact between the Ga catalytic droplet at the tip of the NW and the AZO electrode. The current-voltage measurements of a single GaAs NW diode under different illumination conditions show a strong light responsivity of the forward bias characteristic mainly produced by a change on the series resistance

On the feasibility of the use of wind SAR to downscale waves on shallow water

n recent years, wave reanalyses have become popular as a powerful source of information for wave climate research and engineering applications. These wave reanalyses provide continuous time series of offshore wave parameters; nevertheless, in coastal areas or shallow water, waves are poorly described because spatial resolution is not detailed. By means of wave downscaling, it is possible to increase spatial resolution in high temporal coverage simulations, using forcing from wind and offshore wave databases. Meanwhile, the reanalysis wave databases are enough to describe the wave climate at the limit of simulations; wind reanalyses at an adequate spatial resolution to describe the wind structure near the coast are not frequently available. Remote sensing synthetic aperture radar (SAR) has the ability to detect sea surface signatures and estimate wind fields at high resolution (up to 300?m) and high frequency. In this work a wave downscaling is done on the northern Adriatic Sea, using a hybrid methodology and global wave and wind reanalysis as forcing. The wave fields produced were compared to wave fields produced with SAR winds that represent the two dominant wind regimes in the area: the bora (ENE direction) and sirocco (SE direction). Results show a good correlation between the waves forced with reanalysis wind and SAR wind. In addition, a validation of reanalysis is shown. This research demonstrates how Earth observation products, such as SAR wind fields, can be successfully up-taken into oceanographic modeling, producing similar downscaled wave fields when compared to waves forced with reanalysis wind

Single GaAs nanowire based photodetector fabricated by dielectrophoresis

Mechanical manipulation of nanowires (NWs) for their integration in electronics is still problematic because of their reduced dimensions, risking to produce mechanical damage to the NW structure and electronic properties during the assembly process. In this regard, contactless NW manipulation based methods using non-uniform electric fields, like dielectrophoresis (DEP) are usually much softer than mechanical methods, offering a less destructive alternative for integrating nanostructures in electronic devices. Here, we report a feasible and reproducible dielectrophoretic method to assemble single GaAs NWs (with radius 35–50 nm, and lengths 3–5 μm) on conductive electrodes layout with assembly yields above 90% per site, and alignment yields of 95%. The electrical characteristics of the dielectrophoretic contact formed between a GaAs NW and conductive electrodes have been measured, observing Schottky barrier like contacts. Our results also show the fast fabrication of diodes with rectifying characteristics due to the formation of a low-resistance contact between the Ga catalytic droplet at the tip of the NW when using Al doped ZnO as electrode. The current-voltage characteristics of a single Ga-terminated GaAs NW measured in dark and under illumination exhibit a strong sensitivity to visible light under forward bias conditions (around two orders of magnitude), mainly produced by a change on the series resistance of the device

AlxIn1−xN on Si (100) Solar Cells (x = 0–0.56) Deposited by RF Sputtering

We investigate the photovoltaic performance of solar cells based on n-AlxIn1−xN (x = 0–0.56) on p-Si (100) hetero-junctions deposited by radio frequency sputtering. The AlxIn1−xN layers own an optical bandgap absorption edge tuneable from 1.73 eV to 2.56 eV within the Al content range. This increase of Al content results in more resistive layers (≈10−4–1 Ω·cm) while the residual carrier concentration drops from ~1021 to ~1019 cm−3 . As a result, the top n-contact resistance varies from ≈10−1 to 1 MΩ for InN to Al0.56In0.44N-based devices, respectively. Best results are obtained for devices with 28% Al that exhibit a broad external quantum efficiency covering the full solar spectrum with a maximum of 80% at 750 nm, an open-circuit voltage of 0.39 V, a short-circuit current density of 17.1 mA/cm2 and a conversion efficiency of 2.12% under air mass 1.5 global (AM1.5G) illumination (1 sun), rendering them promising for novel low-cost III-nitride on Si photovoltaic devices. For Al contents above 28%, the electrical performance of the structures lessens due to the high top-contact resistivityThis research was funded by the national projects from the Ministry of Research and Innovation TEC2017-84378-R and NERA (RTI2018-101037-B-I00); the projects from the Comunidad de Madrid SINFOTON2-CM (P2018/NMT-4326), MADRID-PV2 (P-2018/EMT-4308) and SOLA (CM/JIN/2019-013); the projects from the University of Alcalá ANIS (CCG2018/EXP-042) and PISA (CCG19/IA-005); and by the FEDER program. R. Blasco acknowledges the financial support of his contract associated with the Ramon y Cajal Fellowship RYC-2013-1408

Engineering Deoxysugar Biosynthetic Pathways from Antibiotic-Producing Microorganisms A Tool to Produce Novel Glycosylated Bioactive Compounds

AbstractA plasmid (pLN2) was generated in which genes involved in the biosynthesis of L-oleandrose in the oleandomycin producer Streptomyces antibioticus ATCC11891 were cloned. pLN2 was used to direct the biosynthesis of different deoxysugars by exchanging and/or adding genes from other antibiotic biosynthetic clusters. Transfer of the synthesized deoxysugars to the tetracenomycin C aglycon, 8-demethyl-tetracenomycin C, through the use of the “sugar flexible” glycosyltransferase ElmGT, validated the system. Several pLN2 derivatives were constructed by replacement of the oleU 4-ketoreductase gene by different 4-ketoreductase genes. Some of them, such as EryBIV and UrdR, reduced the keto group of the 4-keto intermediates, generating L-olivosyl and D-olivosyl derivatives, respectively. The system was also used to generate an L-rhamnosyl derivative (through a two-gene deletion) and an L-rhodinosyl derivative (through a combination of a gene replacement and a gene addition)

Growth of silicon- and carbon-doped GaAs by chemical beam epitaxy using H2-diluted DTBSi and CBr4 precursors

A wide range of n- and p-type doping levels in GaAs layers grown by chemical beam epitaxy is achieved by using H2-diluted DTBSi and CBr4 as gas precursors for Si and C, respectively. We show that the doping level can be varied by modifying either the concentration or the flux of the diluted precursor. Specifically, we demonstrate carrier concentrations of 7.8 × 1017 –1.4 × 1019 cm−3 for Si, and 1 × 1017 –3.8 × 1020 cm−3 for C, as determined by Hall effect measurements. The dependence of Si incorporation on the diluted-precursor flux is found to be linear. In contrast, we observe a superlinear behavior for C doping. The dependence of the electron and hole mobility values on the carrier concentration as well as the analysis of the layers by low-temperature (12 K) photoluminescence spectroscopy indicate that the use of H2 for diluting DTBSi or CBr4 has no effect on the electrical and optical properties of GaAsThis work was supported by the former Ministerio de Ciencia, Innovación y Universidades under Project No. TEC2016-78433-R and the current Ministerio de Ciencia e Innovación under Project No. PID2020-114280RB-I00. S. Fernández-Garrido and N. López acknowledge the final support received through the Spanish program Ramón y Cajal (co-financed by the European Social Fund) under Grants No. RYC2016-19509 and RYC-2016-20588, respectively, from the former Ministerio de Ciencia, Innovación y Universidades. N. López also acknowledges the funding received through the European ERC Starting Grant No. 75888