Spin-to-charge current conversion in systems with spin-orbit coupling

145 p.This thesis is based on the experimental study of spin-to-charge current conversion (SCC) phenomena that occur in systems with spin-orbit coupling: spin Hall effect (SHE) and anomalous Hall effect (AHE). The main objective is to unveil the mechanisms that give rise to SCCs, in order to show the path to enhance the conversion efficiency for plausible technological applications. In the first part, the SHE is studied in Pt and Ta using the spin absorption technique. The weight of intrinsic and extrinsic mechanisms is extracted and a clear path to enhance the conversion efficiency is shown. Next, a Pt/graphene-based spin-to-charge current converter is explored where two orders of magnitude larger output signals, originated from SCC, have been obtained. In the second part, the relation between SHE and AHE is studied in 3d ferromagnets (FMs). The results show that both effects are not related by the current spin polarization of the FM, as it is generally assumed, and lead us to suggest the presence of an extra mechanism only in the SHE of 3d FMs. Finally, we analyse an interfacial mechanism that contributes to the AHE of Co when a Bi2O3 capping layer is added on top of the FM.CICnanoGUN

Spin-to-charge current conversion in systems with spin-orbit coupling

145 p.This thesis is based on the experimental study of spin-to-charge current conversion (SCC) phenomena that occur in systems with spin-orbit coupling: spin Hall effect (SHE) and anomalous Hall effect (AHE). The main objective is to unveil the mechanisms that give rise to SCCs, in order to show the path to enhance the conversion efficiency for plausible technological applications. In the first part, the SHE is studied in Pt and Ta using the spin absorption technique. The weight of intrinsic and extrinsic mechanisms is extracted and a clear path to enhance the conversion efficiency is shown. Next, a Pt/graphene-based spin-to-charge current converter is explored where two orders of magnitude larger output signals, originated from SCC, have been obtained. In the second part, the relation between SHE and AHE is studied in 3d ferromagnets (FMs). The results show that both effects are not related by the current spin polarization of the FM, as it is generally assumed, and lead us to suggest the presence of an extra mechanism only in the SHE of 3d FMs. Finally, we analyse an interfacial mechanism that contributes to the AHE of Co when a Bi2O3 capping layer is added on top of the FM.CICnanoGUN

Caracterización de las diferencias de sexo en artritis reumatoide mediante el metaanálisis de estudios transcriptómicos

[ES] Las enfermedades autoinmunes, entre ellas la artritis reumatoide, presentan una mayor prevalencia en mujeres que en hombres. Según la literatura, el sistema inmunitario actúa de forma diferencial entre sexos. Aunque las hormonas sexuales desempeñan un papel fundamental, no se conocen por completo las diferencias en los mecanismos moleculares. Una mejor comprensión de estos mecanismos proporcionaría una mayor precisión en el diagnóstico y la personalización de tratamientos en función del sexo. El objetivo de este Trabajo Final de Grado es, por lo tanto, la identificación y comprensión de los mecanismos moleculares diferenciales que subyacen a la artritis reumatoide por sexos, con el fin de mejorar el diagnóstico y la selección de los tratamientos para cada grupo de pacientes. Para ello, se realizó, en primer lugar, una revisión sistemática de estudios de artritis reumatoide con datos de microarrays de expresión génica o RNA-seq de individuos sanos y pacientes. Se recopilaron 5 datasets con 570 muestras del repositorio GEO. A continuación, se analizaron individualmente los cinco estudios seleccionados. Este paso incluyó un análisis exploratorio, un análisis de expresión diferencial y un análisis de enriquecimiento funcional de procesos biológicos de la Gene Ontology (GO) y de rutas KEGG. Finalmente, se llevó a cabo un metaanálisis de genes mediante un modelo de efectos aleatorios, seguido de un enriquecimiento funcional de los resultados globales. De este modo, se identificaron 10 biomarcadores, 90 procesos biológicos y 11 rutas KEGG específicos de sexo estadísticamente significativos. Además, los resultados del enriquecimiento se sintetizaron empleando la herramienta REVIGO y los términos GO slim. Entre otras funciones, los resultados sugieren una actividad aumentada del sistema inmune en la mujer enferma, ligada a una mayor presencia de precursores energéticos; así como una sobrerrepresentación de términos relacionados con la síntesis proteica y la regulación negativa de los osteoblastos en hombres con artritis reumatoide. En definitiva, este estudio ha permitido caracterizar las diferencias de sexo en pacientes con artritis reumatoide, identificando biomarcadores y funciones sobrerrepresentados en cada sexo. Estos hallazgos podrían conducir al descubrimiento de nuevas dianas terapéuticas y proporcionar la base para futuras investigaciones dirigidas a la medicina de precisión en la artritis reumatoide.[EN] Autoimmune diseases, including rheumatoid arthritis (RA), are more prevalent in women than in men. According to the literature, the immune system acts differently between the sexes. Although sex hormones play a key role, the differences in the molecular mechanisms are not fully understood. A better understanding of these mechanisms could provide greater diagnostic precision and personalised treatments by sex. Therefore, the aim of this Final Degree Project was to identify and understand the molecular mechanisms underlying sex-based differences in rheumatoid arthritis, to improve the diagnosis and the selection of treatment for each group of patients. This goal was achieved in three steps. First, we conducted a systematic review of rheumatoid arthritis studies with gene expression microarray or RNA-seq data from healthy individuals and patients. Five datasets that included 570 samples were retrieved from the Gene Expression Omnibus (GEO) repository. Second, the selected studies were individually analysed. This step included an exploratory analysis, a differential expression analysis, and a functional enrichment analysis of biological processes from the Gene Ontology (GO) and KEGG pathways. Finally, we performed a gene meta-analysis using a random effects model, followed by a functional enrichment of the overall results. Thus, our analysis revealed 10 biomarkers, 90 biological processes and 11 KEGG pathways as significantly sex-dependent. In addition, the results were synthesized using the REVIGO tool and GO slim terms. Among other functions, the outcomes from the enrichment suggest an increased activity of the immune system and a greater presence of energy precursors in female RA patients. Male RA patients, instead, showed an overrepresentation of terms related to protein biosynthesis and negative regulation of osteoblasts. In conclusion, we were able to characterise sex differences in patients with rheumatoid arthritis, identifying biomarkers and functions overrepresented in each sex. Our findings could lead to the discovery of new therapeutic targets and be the basis of future research devoted to sex-specific precision medicine in rheumatoid arthritis.Urrutia Lafuente, E. (2021). Caracterización de las diferencias de sexo en artritis reumatoide mediante el metaanálisis de estudios transcriptómicos. Universitat Politècnica de València. http://hdl.handle.net/10251/171163TFG

As2Te3-ren isolatzaile topologikorako presiopeko trantsizioaren ab-initio azterketa

Materia kondentsatuko sikan erronka nagusietako bat naturako materialen izaera eza- gutu eta ezaugarritzea da. Orain dela urte batzuk arte ezagutzen genituen material guztiak, eroale, erdieroale edo isolatzaileak ziren, materialeko balentzia elektroien izae- raren arabera. Azken urteotan sikako arlo honetan burututako lanek eman dute bere fruitua, materiaren egoera berri bat aurkitu baita naturan [1]: isolatzaile topologikoa. Isolatzaile topologikoak material isolatzaileak dira baina ertza eroalea dute. Egoera eroale hauek dira material berri honen berezkotasuna. Egoerok sistemaren topologia dela eta existitzen dira eta sistemaren simetriaren bidez babestuta daudenez, deusez- taezinak dira. Hall isolatzaile kuantikoa izan zen isolatzaile topologikoen gaia teorikoki garatzen hasteko inspirazio iturria eta esperimentalki beranduago aurkitu ziren [2]. Lan ugari egiten ari da materiaren egoera berri honen teoria osatu eta era honetako material berriak aurkitzeko. Gaur egun isolatzaile topologiko ezagunenetarikoak kalogenuro fami- liakoak dira. Talde honetakoa da 2008.urtean estrainekoz aurkitu zen hiru dimentsiotako isolatzaile topologikoa: Bi1xSbx [3]. Beranduago talde honetako Bi2Te3, Bi2Se3 eta Sb2Te3 isolatzaile topologiko direla ere frogatu da [4]. Aipaturiko konposatu guzti hauek R3m talde espazialari dagokion egitura aurkezten dute baldintza normaletan. Sb2Se3 konposatuak bestalde, R3m egitura presiopean erakusten du eta presiopean soilik, iso- latzaile topologikoa dela frogatu da [5]. Lan honetan gure alea gehitzeko, isolatzaile topologikoa izan daitekeen hautagai bat pro- posatu dugu: As2Te3. Konposatu honek bi egitura hartzen ditu eta hoietako bat R3m egitura da, printzipioz presiopean dagoenean erakusten duena [6]. Gure helburua beraz, As2Te3 presiopean isolatzaile topologikoa izan daitekeen aztertzea izan da. Horretarako, material honen egitura elektronikoa ezaugarritu eta aztertu da presiopean teorikoki. Gradu amaierako lan hau lau atal nagusitan banatzen da. Aurreneko bi ataletan, lan hau garatzeko beharrezkoak izan diren kontzeptu teorikoak jaso dira. Isolatzaile topologikoak landu dira lehendabizi, gaiaren oinarrizko ikuspuntu bat planteatu delarik eta bigarren atalean, burutu diren ab-initio kalkulu teorikoen oinarria azaldu da. Hirugarren atalean, lorturiko kalkulo teorikoen emaitzak aurkeztu, aztertu eta interpretatu dira. Laugarren eta azken atalean, lan honetatik ateratako ondorioak bildu eta aurrerago eman ahal izango diren hurrengo pausuak proposatu dira

Innovations for smoke management in passenger trains

Spanish manufacturer Construcciones y Auxiliar de Ferrocarriles developed an innovative alternative for compartmentation, based on a smoke extraction system, to guarantee safe conditions during evacuation processes in a passenger unit. To demonstrate its performance in a train unit, a real-scale experimental programme, supported by the application of fire computer modelling, was applied in a new Construcciones y Auxiliar de Ferrocarriles' rolling stock. The new smoke exhaust system aims to extract the smoke generated during a fire in the passenger area by exhaust fans of the heating, ventilation, and air conditioning system, allowing the ingress of fresh exterior air in the lower part of the rear ends of the car. These key elements create an air flow that evacuates the smoke to prevent people from being exposed to it. Full-scale fire tests were developed in the train unit following the Australian standard AS 4391-1999. A fire of 140kW was used, and the smoke was generated by a clean smoke machine. Measurement points included six thermocouple trees, 10 gas flow velocity probes and two GoPro HD video cameras (for the estimation of the visibility). The system performance was successful with the tenability criteria, since the value of visibility at the non-fire car was greater than 30 m and the temperature was lower than 30°C during all the tests at a height of 1.7m above the floor. Experimental results were used to validate the computational model. The computational model results show a good accuracy compared with the tests

Characterization of the Common Genetic Variation in the Spanish Population of Navarre

Large-scale genomic studies have significantly increased our knowledge of genetic variability across populations. Regional genetic profiling is essential for distinguishing common benign variants from disease-causing ones. To this end, we conducted a comprehensive characterization of exonic variants in the population of Navarre (Spain), utilizing whole genome sequencing data from 358 unrelated individuals of Spanish origin. Our analysis revealed 61,410 biallelic single nucleotide variants (SNV) within the Navarrese cohort, with 35% classified as common (MAF > 1%). By comparing allele frequency data from 1000 Genome Project (excluding the Iberian cohort of Spain, IBS), Genome Aggregation Database, and a Spanish cohort (including IBS individuals and data from Medical Genome Project), we identified 1069 SNVs common in Navarre but rare (MAF ≤ 1%) in all other populations. We further corroborated this observation with a second regional cohort of 239 unrelated exomes, which confirmed 676 of the 1069 SNVs as common in Navarre. In conclusion, this study highlights the importance of population-specific characterization of genetic variation to improve allele frequency filtering in sequencing data analysis to identify disease-causing variants

Spanish HTT gene study reveals haplotype and allelic diversity with possible implications for germline expansion dynamics in Huntington disease

We aimed to determine the genetic diversity and molecular characteristics of the Huntington disease (HD) gene (HTT) in Spain. We performed an extended haplotype and exon one deep sequencing analysis of the HTT gene in a nationwide cohort of population-based controls (n = 520) and families with symptomatic individuals referred for HD genetic testing. This group included 331 HD cases and 140 carriers of intermediate alleles. Clinical and family history data were obtained when available. Spanish normal alleles are enriched in C haplotypes (40.1%), while A1 (39.8%) and A2 (31.6%) prevail among intermediate and expanded alleles, respectively. Alleles ≥50 CAG repeats are primarily associated with haplotypes A2 (38.9%) and C (32%), which are also present in 50% and 21.4%, respectively, of HD families with large intergenerational expansions. Non-canonical variants of exon one sequence are less frequent, but much more diverse, in alleles of ≥27 CAG repeats. The deletion of CAACAG, one of the six rare variants not observed among smaller normal alleles, is associated with haplotype C and appears to correlate with larger intergenerational expansions and early onset of symptoms. Spanish HD haplotypes are characterised by a high genetic diversity, potentially admixed with other non-Caucasian populations, with a higher representation of A2 and C haplotypes than most European populations. Differences in haplotype distributions across the CAG length range support differential germline expansion dynamics, with A2 and C showing the largest intergenerational expansions. This haplotype-dependent germline instability may be driven by specific cis-elements, such as the CAACAG deletion