UHF power conversion with GaN HEMT class-E2 topologies

This paper reviews the use of UHF double class-E (class-E2) topologies for dc/dc power conversion. After introducing this attractive resonant converter in the context of the time-reversal duality principle, two different lumped-element networks are described for appropriately terminating the drain of the switching devices. Recent implementation examples, taking advantage of GaN HEMT processes, are then presented. The potential for a fast dynamic response is validated (with a slew rate over 2 V/nS), while also the feasibility for an appropriate operation without requiring external RF gate driving signals. A solution for approximating a load-insensitive operation is finally exposed

UHF Class-E power amplifier design for wide range variable resistance operation

This paper presents a simple switch model for a GaN HEMT device, extracted to estimate the output power and efficiency load-pull contours when the transistor is used in a UHF class-E power amplifier (PA). The impact of model parameters on the theoretical achievable efficiency versus output power backoff (PBO) profile is considered, to then be used in a load-insensitive class-E design methodology. A simple lumped element terminating network, derived from [1], was selected to approximate the desired zero voltage switching (ZVS) operation along a wide range of resistive loads. A 700 MHz outphasing transmitter, amenable to be transformed into a resonant dc/dc power converter, has been implemented for validation. Drain efficiency peaks of 82.2% and 78% have been measured for each application case, with values above 70% and 60% at 10 dB of backoff and 30% of nominal dc output power, respectively.This work was supported by the Ministry of Economy and Competitiveness (MINECO) through TEC2014-58341-C4-1-R and TEC2017-83343-C4-1-R projects, co-funded with FEDER. D. Vegas and M. Pampín also thank the support provided by the pre-doctoral BES-2015-072203 and BES-2012-059599 grants, respectively

Anti-carbamylated protein antibodies as a reproducible independent type of rheumatoid arthritis autoantibodies

A large fraction of the patients with rheumatoid arthritis (RA) develop specific autoantibodies, which until recently were only of two types, rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA). We aimed to replicate important findings about a recently described third type of specific autoantibodies, anti-carbamylated protein (anti-CarP) antibodies, because they have been described based only in the homemade ELISA from a single laboratory. Our study included 520 patients with established RA and 278 healthy controls of Spanish ancestry and it was done with an independently performed ELISA. The prevalence and pattern of environmental, clinical and genetic associations of the anti-CarP antibodies were similar to the previously described. Notably, the presence and titers of anti-CarP correlated with the presence and titers of ACPA, but the anti-CarP antibodies did not share the known genetic and exposure risk factors of the ACPA. In addition, anti-CarP antibodies were independently associated with a higher (10.5%) prevalence of bone erosions. The reproducibility of these characteristics across laboratories and European subpopulations, indicates the wide validity of the results and suggests that determination of anti-CarP antibodies could contribute to explain RA pathogenesis and identify clinically relevant patient subgroups.Funding was provided by the Instituto de Salud Carlos III, PI14/01651; and Instituto de Salud Carlos III, RD12/0009/0008. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S

New Morphiceptin Peptidomimetic Incorporating (1S,2R,3S,4S,5R)-2-Amino-3,4,5-trihydroxycyclopen-tane-1-carboxylic acid: Synthesis and Structural Study

We present the synthesis and structural study of a new peptidomimetic of morphiceptin, which can formally be considered as the result of the replacement of the central proline residue of this natural analgesic drug with a subunit of (1S,2R,3S,4S,5R)-2-amino-3,4,5-trihydroxycyclopentane-1-carboxylic acid, previously obtained from L-idose. An optimized synthesis of this trihydroxylated cispentacin derivative is also reported. Molecular docking calculations on the target receptor support a favorable role of the hydroxy substituents of the non-natural β-amino acid incorporated into the peptidomimeticThis work has received financial support from the Spanish Ministry of Science and Innovation (CTQ2009-08490), the Xunta de Galicia (Centro Singular de Investigación de Galicia, Centro singular de investigación de Galicia accreditation 2019-2022, ED431G 2019/03; Project CN2011/037, project ED431C 2018/04 and Project GRC2014/040), the Principado de Asturias (FICYT IDI/2018/000181) and the European Union (European Regional Development Fund-ERDF). Partial financial support by Arcelor Mittal (R&D-Principado de Asturias; FUO-286-18). Conicyt research fellowship to ML (PFCHA/Doctorado Nacional/2018-21180427)S

Particular association of clinical and genetic features with autoimmunity to citrullinated α-enolase in rheumatoid arthritis.

OBJECTIVE: To confirm that the presence of anti-citrullinated alpha-enolase peptide 1 (anti-CEP-1) antibodies identifies a subgroup of patients with rheumatoid arthritis (RA). METHODS: DNA and serum samples were obtained from 451 patients with RA and 279 healthy control subjects, all of whom were of Spanish ancestry. Antibodies to cyclic citrullinated peptide (CCP) and CEP-1 were measured by enzyme-linked immunosorbent assay. HLA-DRB1 and the R620W single-nucleotide polymorphism of PTPN22 were genotyped. RESULTS: Anti-CEP-1 and anti-CCP antibodies were observed in 26.8% and 71.2% of the patients with RA, respectively. Most of the patients (86.6%) with anti-CEP-1 antibodies also had anti-CCP antibodies. Erosive arthritis, rheumatoid factor (RF) positivity, and the presence of the HLA shared epitope (especially the DRB1*04 alleles) were disproportionately associated with the group of patients with both antibodies. In addition, evidence of a significant interaction between the shared epitope and the risk allele of PTPN22 was observed only in these patients. In contrast, the association with these clinical and genetic features was weaker in patients with anti-CCP antibodies but lacking anti-CEP-1 antibodies. These results were obtained in patients in whom the prevalence of RA risk factors differed from that in other previously studied patients. CONCLUSION: We observed that autoimmunity against citrullinated alpha-enolase may identify a subset of patients with a higher frequency of joint erosions and RF positivity. In addition, we confirmed the disproportionately large effect of the susceptibility alleles of HLA-DRB1 and their interaction with PTPN22 in this subset of patients. These results extend, confirm, and generalize the evidence supporting the specificity of the anti-CEP-1 antibody-positive subgroup of patients with RA among anti-CCP antibody-positive patients with RA

Diseño de un amplificador de alta eficiencia a GaN HEMT en 2.6 GHz

In this paper, a highly efficient GaN HEMT power amplifier (PA) for 2.6 GHz LTE band is presented. Using the nonlinear model of the selected device, the drain terminating and biasing networks are designed to provide near optima impedance values at the fundamental and higher order harmonics. The second and third harmonics terminations have been specially taken into account in order to obtain the best performance by means of a series of load-pull simulations. Good efficiency and PAE profiles have been obtained at the selected frequency band with the implemented amplifier. A peak of efficiency close to 80% has been measured at 2.6 GHz.Este trabajo ha sido posible gracias al soporte proporcionado por el Ministerio de Economía y Competitividad (MINECO) a través del TEC2014-58341-C4-1-R cofinanciado con fondos FEDER. David Vegas agradece también el apoyo recibido a través del contrato predoctoral BES-2015-072203

Diseño de un amplificador clase E compacto en 2.14 GHz

In this paper, a simple and direct methodology is followed for the design of a compact class E RF power amplifier (RFPA). Characterizing the ON-state resistance and the OFF-state output capacitance, initial values for the efficiency and the optimum drain impedance are estimated, according to class E theory. Taking into consideration the usually undesired parasitics of lumped elements, a multi-harmonic drain terminating network is then adjusted with an air core coil and a few multilayer ceramic capacitors. After input matching, a 70% power added efficiency (PAE) value has been measured at 2.14 GHz for an output power of 10.9 W. The highly linear Vdd-to-AM profile is amenable for its use in polar transmitters

Performance and microbial features of the partial nitritation-anammox process treating fish canning wastewater with variable salt concentrations

The partial nitritation-anammox (PN-AMX) process applied to wastewaters with high NaCl concentration was studied until now using simulated media, without considering the effect of organic matter concentration and the shift in microbial populations. This research work presents results on the application of this process to the treatment of saline industrial wastewater. Obtained results indicated that the PN-AMX process has the capability to recover its initial activity after a sudden/acute salt inhibition event (up to 16 g NaCl/L). With a progressive salt concentration increase for 150 days, the PN-AMX process was able to remove the 80% of the nitrogen at 7–9 g NaCl/L. The microbiological data indicated that NaCl and ammonia concentrations and temperature are important factors shaping PN-AMX communities. Thus, the NOB abundance (Nitrospira) decreases with the increase of the salt concentration, while heterotrophic denitrifiers are able to outcompete anammox after a peak of organic matter in the feedingThis work was supported by the Spanish Government through GRANDSEA (CTM2014-55397-JIN) and FISHPOL (CTQ2014-55021-R) projects co-funded by FEDER, and the Chilean Government (CONICYT/FONDAP/15130015). The authors from the USC belong to CRETUS (AGRUP2015/02) and the Galician Competitive Research Group (GRC 2013-032), programs co-funded by FEDERS

Amplificador de potencia doble-banda (1.8 GHz y 2.6 GHz) con alta eficiencia

This work presents a methodology to design highefficient dual-band RF power amplifiers. Using the non-linear model of the selected GaN HEMT device, an analysis of the performance of the transistor to changes in the phases of both the second and the third harmonic has been carried out for both frequencies. Based on this analysis, drain terminating and biasing networks are designed to provide near optima impedance values at the fundamental and higher order harmonics to the selected frequency bands. The experimental characterization of the implemented prototype, which operates at 1.8 GHz and 2.6 GHz, can achieve drain efficiencies around 70 % with output power levels greater than 42 dBm in both frequency bands. Furthermore, PAEs obtained are very close to drain efficiencies after dual-band input matching.Este trabajo ha sido financiado por el Gobierno de Espana bajo los proyectos TEC2014-58341-C4-1-R y TEC2014-58341-C4-2-R del MINECO, por el FEDER, por el FSE, a través de la beca FPI del MINECO del primer autor (BES-2012-061813). Además, el primer autor agradece la beca de movilidad predoctoral del MINECO (EEBB-I-15-10447

Non-HLA genes PTPN22, CDK6 and PADI4 are associated with specific autoantibodies in HLA-defined subgroups of rheumatoid arthritis

Introduction: Genetic susceptibility to complex diseases has been intensively studied during the last decade, yet only signals with small effect have been found leaving open the possibility that subgroups within complex traits show stronger association signals. In rheumatoid arthritis (RA), autoantibody production serves as a helpful discriminator in genetic studies and today anti-citrullinated cyclic peptide (anti-CCP) antibody positivity is employed for diagnosis of disease. The HLA-DRB1 locus is known as the most important genetic contributor for the risk of RA, but is not sufficient to drive autoimmunity and additional genetic and environmental factors are involved. Hence, we addressed the association of previously discovered RA loci with disease-specific autoantibody responses in RA patients stratified by HLA-DRB1*04. Methods: We investigated 2178 patients from three RA cohorts from Sweden and Spain for 41 genetic variants and four autoantibodies, including the generic anti-CCP as well as specific responses towards citrullinated peptides from vimentin, alpha-enolase and type II collagen. Results: Our data demonstrated different genetic associations of autoantibody-positive disease subgroups in relation to the presence of DRB1*04. Two specific subgroups of autoantibody-positive RA were identified. The SNP in PTPN22 was associated with presence of anti-citrullinated enolase peptide antibodies in carriers of HLA-DRB1*04 (Cochran-Mantel-Haenszel test P = 0.0001, P corrected <0.05), whereas SNPs in CDK6 and PADI4 were associated with anti-CCP status in DRB1*04 negative patients (Cochran-Mantel-Haenszel test P = 0.0004, P corrected <0.05 for both markers). Additionally we see allelic correlation with autoantibody titers for PTPN22 SNP rs2476601 and anti-citrullinated enolase peptide antibodies in carriers of HLA-DRB1*04 (Mann Whitney test P = 0.02) and between CDK6 SNP rs42041 and anti-CCP in non-carriers of HLA-DRB1*04 (Mann Whitney test P = 0.02). Conclusion: These data point to alternative pathways for disease development in clinically similar RA subgroups and suggest an approach for study of genetic complexity of disease with strong contribution of HLA