Broadband transverse susceptibility in multiferroic Y-type hexaferrite Ba0.5Sr1.5Zn2Fe12O22

Producción CientíficaNoncollinear spin systems with magnetically induced ferroelectricity from changes in spiral magnetic ordering have attracted significant interest in recent research due to their remarkable magnetoelectric effects with promising applications. Single phase multiferroics are of great interest for these new multifunctional devices, being Y-type hexaferrites good candidates, and among them the ZnY compounds due to their ordered magnetic behaviour over room temperature. Polycrystalline Y type hexaferrites with composition Ba0.5Sr1.5Zn2Fe2O22 (BSZFO) were sintered in 1050 °C–1250 °C temperature range. Transverse susceptibility measurements carried out on these BSZFO samples in the temperature range 80–350 K with DC fields up to ± 5000 Oe reveal different behaviour depending on the sintering temperature. Sample sintered at 1250 °C is qualitatively different, suggesting a mixed Y and Z phase like CoY hexaferrites. Sintering at lower temperatures produce single phase Y-type, but the transverse susceptibility behaviour of the sample sintered at 1150 °C is shifted at temperatures 15 K higher. Regarding the DC field sweeps the observed behaviour is a peak that shifts to lower values with increasing temperature, and the samples corresponding to single Y phase exhibit several maxima and minima in the 250 K–330 K range at low DC applied field as a result of the magnetic field induced spin transitions in this compound.Ministerio de Ciencia, Innovación y Universidades; Agencia Estatal de Investigación with FEDER (MAT2016-80784-P

Synthesis, structural characterization and broadband ferromagnetic resonance in Li ferrite nanoparticles

Producción CientíficaLithium ferrites are well known materials due to its numerous technological applications especially in microwave devices. Lithium ferrite nanoparticles were prepared by sol-gel technique by means of Pechini method, and then annealed at different temperatures in 250–1000 °C range. XRD confirms spinel formation with particles sizes in 15–700 nm range, with increased size with annealing temperature, whereas FTIR and Raman measurement confirm that single phase lithium ferrite with ordered cationic structure is obtained. Microwave magnetoabsorption data of the annealed lithium ferrite nanoparticles were obtained with a broadband system based on a network analyzer that operates up to 8.5 GHz. At fields up to 200 mT we can observe a broad absorption peak that shifts to higher frequencies with magnetic field according to ferromagnetic resonance theory. The amplitude of absorption, up to 85%, together with the frequency width of about 5.5 GHz makes this material suitable as wave absorber. FMR parameters like resonance field, linewidth and broadening are analyzed in order to obtain the characteristic parameters and analyze the microwave behaviour.Ministerio de Economía, Industria y Competitividad ( project MAT2016-80784-P

The Sustainable Management of Metals: An Analysis of Global Research

The objective of this study was to analyze research trends in the field of sustainable management of metals on a global level between 1993 and 2017. To do so, a bibliometric analysis was carried out on a total of 6967 articles. The results revealed the growing interest in this research field, particularly over the last five year-period during which 63% of all articles were published. The three journals in which most articles had been published were the Journal of Cleaner Production, ACS Sustainable Chemistry and Engineering, and Chemsuschem. The countries that published the most articles were China, the United States, India, Germany, and the United Kingdom. A sizeable network of collaboration has been established between countries for the joint publication of studies. The main lines of research have been focused on metal decontamination in water and soil, waste management oriented towards reuse and recycling, and the innovation of processes for cleaner and more efficient production. The results revealed the need for comprehensive studies that integrate different disciplines within the same analytical framework, and to promote research that contributes to the different dimensions of sustainability (environmental, economic, and social)

Genome-Wide Analysis of microRNA Expression Profile in Roots and Leaves of Three Wheat Cultivars under Water and Drought Conditions

The following are available online at https://www.mdpi.com/article/ 10.3390/biom13030440/s1. Figure S1: Fraction of different RNA species. Figure S2: Read length distribution of all genome mapped reads (a) from total reads (redundant reads) and (b) from unique reads (non-redundant reads. Figure S3: Library normalized RPM values distribution per sample of novel miRNAs. Figure S4: qRT-PCR analysis of the expression of novel miRNA Tae-mir-novel54-5p and known miRNA Tae-miR827c in 10 samples. Figure S5: Network analysis of (a) target genes by drought downregulated miRNAs and (b) drought upregulated miRNAs in leaves. Table S1: Quality and read mapping report. Table S2: Fraction of different RNA species. Table S3: Read length distribution of all genome mapped reads from total reads (redundant reads). Table S4: Read length distribution of all genome mapped reads from unique reads (non-redundant reads. Table S5: All miRNAs expression matrix. Table S6: Expression matrix of all the miRNAs in the SRA datasets. Table S7: miRNA expression matrix of all miRNAs in the Zea mays SRA datasets. Table S8: Degradome based target-gene predicted interactions. Table S9: qRT-PCR assay information. Table S10: Enrichment of functional annotations in miRNA target genes. Table S11: Mature and hairpin sequences of predicted miRNAs. Table S12: Degradome miRNA-target interaction predictions using CleaveLand4.Wheat is one of the most important food sources on Earth. MicroRNAs (miRNAs) play important roles in wheat productivity. To identify wheat miRNAs as well as their expression profiles under drought condition, we constructed and sequenced small RNA (sRNA) libraries from the leaves and roots of three wheat cultivars (Kukri, RAC875 and Excalibur) under water and drought conditions. A total of 636 known miRNAs and 294 novel miRNAs were identified, of which 34 miRNAs were tissue- or cultivar-specific. Among these, 314 were significantly regulated under drought conditions. miRNAs that were drought-regulated in all cultivars displayed notably higher expression than those that responded in a cultivar-specific manner. Cultivar-specific drought response miRNAs were mainly detected in roots and showed significantly different drought regulations between cultivars. By using wheat degradome library, 6619 target genes were identified. Many target genes were strongly enriched for protein domains, such as MEKHLA, that play roles in drought response. Targeting analysis showed that drought-downregulated miRNAs targeted more genes than drought- upregulated miRNAs. Furthermore, such genes had more important functions. Additionally, the genes targeted by drought-downregulated miRNAs had multiple interactions with each other, while the genes targeted by drought-upregulated miRNAs had no interactions. Our data provide valuable information on wheat miRNA expression profiles and potential functions in different tissues, cultivars and drought conditions

Prym varieties, curves with automorphisms and the Sato Grassmannian

Este trabajo trata las variedades de Prym, curvas con automorfismos y Grassmannian de Sato.The aim of the paper is twofold. First, some results of Shiota and Plaza-Martín on Prym varieties of curves with an involution are generalized to the general case of an arbitrary automorphism of prime order. Second, the equations defining the moduli space of curves with an automorphism of prime order as a subscheme of the Sato Grassmannian are given

Optimisation-based design of transversal signal-interference microwave bandpass and lowpass filters with extended stopband

Generalised bi-path stepped-impedance-line signal-interference bandpass and lowpass transversal filtering sections (TFSs) with increased stopband bandwidth above the main transmission band are presented. They are realised by partitioning the two in-parallel transmission-line paths in their related classic spectrally periodic TFS approach into a plurality of line sub-segments, whose characteristic-impedance and electrical-length values are derived through optimisation. It is demonstrated that the stopband range above the transmission band in these generalised non-frequency-periodic TFSs can be remarkably broadened with regard to those intrinsic to their conventional bandpass and lowpass TFS counterparts. Furthermore, as added benefits, this is achieved for shorter transmission-line paths and a sharper cut-off slope between the transmission band and the extended stopband. For experimental-validation purposes, three proof-of-concept microstrip prototypes are manufactured and characterised. They correspond to a 1-GHz bandpass TFS, a 1-GHz two-TFS-in-series-cascade-based bandpass filter (BPF) with augmented selectivity and out-of-band power-rejection levels, and one lowpass TFS with a designed 3-dB cut-off frequency of 1.25 GHz.Agencia Estatal de InvestigaciónEuropean Commissio

Balanced quasi-elliptic-type combline diplexer with multiextracted-pole junction/output sections

A class of coupled-multiline quasi-elliptic-type balanced diplexer device with closely spaced channels and its balanced coupling-routing-diagram formalism to simultaneously model its differential- and common-mode operation are reported. It employs third-order combline-type bandpass filters (BPFs) in its filtering channels, whose resonating lines are connected at one of their extremes to the symmetry plane of the balanced-circuit structure (i.e., virtual grounds for the differential mode), along with a multiextracted-pole/coupled-multiline dual-band BPF junction and single-band BPF output cells. In differential-mode operation, the dual-band BPF junction adds one in-band pole to each diplexer channel and three transmission zeros (TZs) to both channels, whereas the single-band BPF output cells incorporate one in-band pole and two TZs in their corresponding channels. In this manner, increased-selectivity differential-mode BPF transfer functions for the diplexer channels when compared to those of its third-order combline-type BPFs are obtained. Grounded resistors are connected at the symmetry plane of the balanced diplexer for all the resonating lines of the combline-type BPFs, which become detuned with regard to the poles associated with the dual-band BPF junction and the single-band BPF output cells under common-mode excitation. This allows for high common-mode suppression levels in wide spectral ranges to be realized for both channels while maintaining the same TZs as in differential-mode operation. For practical-validation purposes, a 1.6-GHz/1.8-GHz microstrip prototype is manufactured and tested.Ministerio de Economía, Industria y CompetitividadEuropean Commissio

Broadband transverse susceptibility in multiferroic Y-type hexaferrite Ba0.5Sr1.5Co2Fe2O22

Producción CientíficaSingle phase multiferroics in which ordered magnetism and ferroelectricity coexist, are of great interest for new multifunctional devices, and among them Y-type hexaferrites are good candidates. Transverse susceptibility measurements, which have been proved to be a versatile tool to study singular properties of bulk and nanoparticle magnetic systems, have been carried out with a broadband system on polycrystalline Y type hexaferrites with composition Ba0.5Sr1.5Co2Fe2O22, optimal to exhibit multiferroic properties. In the temperature range 80–350 K transverse susceptibility measurements with DC fields up to ±5000 Oe reveal different behaviour depending on the sintering temperature. The thermal evolution of the anisotropy field peak exhibits four regions with different slopes: positive in 80–130 K, negative in 130–200 K, constant in 200–280 K and negative in 280–350 K, which can be considered a signature of spin transitions in this compound.Ministerio de Ciencia, Innovación y Universidades; Agencia Estatal de Investigación with FEDER ( project MAT2016-80784-P

Broadband ferromagnetic resonance in Mn-doped Li ferrite nanoparticles

Producción CientíficaLithium ferrites are well known materials due to their numerous technological applications especially in microwave devices. Mn-doped lithium ferrite nanoparticles were prepared by sol-gel technique by means of Pechini method, and then annealed at different temperatures in 250–1000 °C range. XRD confirms spinel formation with particle size in the 15–200 nm range, with increased size with annealing temperature. Microwave magnetoabsorption data of annealed lithium ferrite nanoparticles, obtained with a broadband system based on a network analyzer operating up to 8.5 GHz are presented. At fields up to 200 m T we can observe a broad absorption peak that shifts to higher frequencies with magnetic field according to ferromagnetic resonance theory. The amplitude of absorption, up to 85%, together with the frequency width of about 4.5 GHz makes this material suitable as wave absorber. Samples annealed at higher temperatures show a behaviour similar to polycrystalline samples, thus suggesting their multidomain character.Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación with FEDER (project MAT2016-80784-P

Input-reflectionless low-pass filter on multilayered diplexer-based topology

A class of two-layered input-reflectionless diplexer-based LPF is reported in this letter. By using a resistively-terminated wideband microstrip vertical transition by the first time for this application, an input-reflectionless response for the conceived LPF device is realized. The RF operational foundations and theoretical examples of this input-reflectionless LPF design approach have been shown and experimentally verified with the development and characterization of a two-LPF-unit microstrip prototype with extended reflectionless stopband.Ministerio de Economía, Industria y CompetitividadEuropean Commissio