Design and characterization of functional nanomaterials on surfaces

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de la Materia Condensada. Fecha de lectura: 21-10-2020The urgent need for developing new strategies to afford the increasing energy demand remains a challenge for many research fields, such as material science or energy engineering. In this respect, the field of nanoscience has emerged as a powerful field towards the design of functional nanomaterials, synthesized from both organic and inorganic materials. This new scientific discipline has led to the design of novel materials and opened up new avenues for traditional compounds. For instance, transition metal oxides have been proposed as promising catalysts in the oxygen evolution reaction for water splitting, of crucial relevance in clean energy. Additionally, the development of organic electronics, focused on the study of the electronic properties of carbon-based materials, plays an important role in the synthesis and transformation of traditional electronics by designing low-cost, flexible and sustainable electronic devices. In this thesis, we have grown and studied different nanomaterials on metallic surfaces related to energy efficiency, targeting to achieve global sustainability. First, we have studied the catalytic activity of CoO at the atomic scale towards the water splitting reaction. We have grown single bilayer CoO nanoislands, where the co-existence of two distinct phases has been observed. Such polymorphism has been rationalized due to the distinct lattice parameter and the registry with the substrate which induces the modification of its electronic properties, reactivity and, hence, of its catalytic activity. In addition, we have shown the capability to tune the phase by an electric field. Second, we have described the on-surface synthesis of new π-conjugated polymers with important applications in organic electronics. An innovative strategy towards the synthesis of low band gap π-conjugated polymers formed by acene or periacene units has been developed, which allows the control of their electronic structure, resonance form and topological quantum class by tuning the repeating unit size. Our results shed light into the atomistic adsorption and dissociation of water on a CoO model catalyst. Furthermore, we introduced pathways for controlling the electronic properties and quantum topological class of one dimensional polymers on metallic surface

Begomovirus quasispecies adapt to hosts by exploring different sequence space without changing their consensus sequences

Geminiviruses possess single-stranded circular DNA genomes that depend on cellular polymerases for replication in the host nucleus. In plant hosts, geminivirus populations behave as ensembles of mutant and recombinant genomes. This favours the emergence of new geminivirus strains able to produce new diseases or overcome the genetic resistance of cultivars. In warm and temperate areas several whitefly-transmitted geminiviruses of the genus Begomovirus cause the tomato yellow leaf curl disease (TYLCD) with important economic consequences. TYLCD is frequently controlled in commercial tomato production using the Ty-1 resistance gene. Over a 45 day period we studied the evolution of infectious clones from three TYLCD-associated begomoviruses: Tomato yellow leaf curl Sardinia virus, Tomato yellow leaf curl virus and the recombinant Tomato yellow leaf curl Axarquia virus. The evolution of their viral progeny was examined in susceptible tomato (ty1/ty1), resistant tomato (Ty1/ty1), common bean, and the wild reservoir Solanum nigrum. We found that in addition to affecting viral accumulation kinetics, the host influenced the sequence space explored by these begomoviruses. In tomato, viral dynamics was not influenced by the presence of the Ty-1 gene. Interestingly, positive adaptation of the coat protein gene was only observed in the common bean and S. nigrum, which correlates with these plants having viral quasispecies with the highest degree of complexity and heterogeneity. Our results underline the importance of analysing the mutant spectra of begomovirus infections, especially in wild reservoirs, which have the potential to give rise to large numbers of emergent variants in spite of the invariance of their consensus sequences.Junta de Andalucía proyecto: P10-CVI-6561. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Ciencia y medios de comunicación

Varios científicos plantean interrogantes y posibilidades sobre los medios y su responsabilidad en la transmisión de la ciencia

Pathogenic strains of Shewanella putrefaciens contain plasmids that are absent in the probiotic strain Pdp11

Shewanella putrefaciens Pdp11 is a strain described as a probiotic for use in aquaculture. However, S. putrefaciens includes strains reported to be pathogenic or saprophytic to fish. Although the probiotic trait has been related to the presence of a group of genes in its genome, the existence of plasmids that could determine the probiotic or pathogenic character of this bacterium is unknown. In the present work, we searched for plasmids in several strains of S. putrefaciens that differ in their pathogenic and probiotic character. Under the different conditions tested, plasmids were only found in two of the five pathogenic strains, but not in the probiotic strain nor in the two saprophytic strains tested. Using a workflow integrating Sanger and Illumina reads, the complete consensus sequences of the plasmids were obtained. Plasmids differed in one ORF and encoded a putative replication initiator protein of the repB family, as well as proteins related to plasmid stability and a toxin-antitoxin system. Phylogenetic analysis showed some similarity to functional repB proteins of other Shewanella species. The implication of these plasmids in the probiotic or pathogenic nature of S. putrefaciens is discussed

Detection of Neutralizing Antibodies against SARS-CoV-2 Post-Vaccination in Health Care Workers of a Large Tertiary Hospital in Spain by Using a Rapid Test LFIC and sVNT-ELISA

The presence of neutralizing antibodies (NAbs) against SARS-CoV-2 represent a surrogate marker of immunologic protection in populations at high risk of infection such as healthcare workers caring for hospitalized patients with COVID-19. As recommended by CDC and the European CDC, the use of rapid diagnostic tests during population-based evaluations offers an opportunity to identify individuals with serologic evidence of natural infection or who have undergone vaccination. We carried out a cross-sectional study to assess the presence of neutralizing antibodies against SARS-CoV-2 among medical providers at an intensive care unit of a large referral hospital in Alicante, Spain. In addition, we tested for the presence of neutralizing antibodies compared to serum of uninfected individuals from a Biobank. We were also interested in evaluating the use of a rapid lateral flow immunochromatography (LFIC) test against a surrogate ELISA viral neutralization test (sVNT). This rapid test demonstrated a specificity of 1.000 95% CI (0.91–1.00) and the sensitivity of 0.987 95% CI (0.93–1.00). The negative predictive value was 95%. After six months, this rapid test demonstrated that those immunized with two doses of BioNTech/Pfizer vaccine, maintained optimal levels of neutralizing antibodies. We concluded that all Health Care Workers develop NAbs and the use of this rapid immunochromatographic test represents a potential tool to be used in population-based studies to detect serological antibody responses to vaccination. Vaccination policies could benefit from this tool to assess additional doses of vaccine or boosters among high-risk populations.This work was supported by an advisory contract from the University of Alicante with reference WENZHOU-OJABIO1-21T and no one reports personal fees received from the biotech company

Electrically Tunable Reactivity of Substrate-Supported Cobalt Oxide Nanocrystals

[EN] First-row transition metal oxides are promising materials for catalyzing the oxygen evolution reaction. Surface sensitive techniques provide a unique perspective allowing the study of the structure, adsorption sites, and reactivity of catalysts at the atomic scale, which furnishes rationalization and improves the design of highly efficient catalytic materials. Here, a scanning probe microscopy study complemented by density functional theory on the structural and electronic properties of CoO nanoislands grown on Au(111) is reported. Two distinct phases are observed: The most extended displays a Moiré pattern (α-region), while the less abundant is 1Co:1Au coincidental (β-region). As a result of the surface registry, in the β-region the oxide adlayer is compressed by 9%, increasing the unoccupied local density of states and enhancing the selective water adsorption at low temperature through a cobalt inversion mechanism. Tip-induced voltage pulses irreversibly transform α- into β-regions, thus opening avenues to modify the structure and reactivity of transition metal oxides by external stimuli like electric fields.This work was supported by the European Union under the H2020 FET-PROACT A-LEAF (Artificial-Leaf ) project (Grant Agreement No. 732840). Barcelona Supercomputing Center. Grant Number: QS-2019-3-002

Microwave versus radiofrequency ablation for the treatment of liver malignancies: a randomized controlled phase 2 trial

[EN] Microwave (MWA) and radiofrequency ablation (RFA) are main ablative techniques for hepatocellular carcinoma (HCC) and colorectal liver metastasis (MT). This randomized phase 2 clinical trial compares the effectiveness of MWA and RFA as well as morphology of corresponding ablation zones. HCC and MT patients with 1.5-4 cm tumors, suitable for ablation, were randomized into MWA or RFA Groups. The primary endpoint was short-to-long diameter ratio of ablation zone (SLR). Primary technical success (TS) and a cumulative local tumor progression (LTP) after a median 2-year follow-up were compared. Between June 2015 and April 2020, 82 patients were randomly assigned (41 patients per group). For the per-protocol analysis, five patients were excluded. MWA created larger ablation zones than RFA (p = 0.036) although without differences in SLR (0.5 for both groups, p = 0.229). The TS was achieved in 98% (46/47) and 90% (45/50) (p = 0.108), and LTP was observed in 21% (10/47) vs. 12% (6/50) (OR 1.9 [95% CI 0.66-5.3], p = 0.238) of tumors in MWA vs. RFA Group, respectively. Major complications were found in 5 cases (11%) vs. 2 cases (4%), without statistical significance. MWA and RFA show similar SLR, effectiveness and safety in liver tumors between 1.5 and 4 cm.This work was supported by a grant for medical research from Spanish Government (FIS-PI12/00799) and by the Spanish Ministerio de Ciencia, Innovacion y Universidades under "Programa Estatal de I+D+i Orientada a los Retos de la Sociedad", Grant RTI2018-094357-B-C21.Radosevic, A.; Quesada, R.; Serlavos, C.; Sánchez, J.; Zugazaga, A.; Sierra, A.; Coll, S.... (2022). Microwave versus radiofrequency ablation for the treatment of liver malignancies: a randomized controlled phase 2 trial. Scientific Reports. 12(1):1-10. https://doi.org/10.1038/s41598-021-03802-xS11012

Differential Shape of Geminivirus Mutant Spectra Across Cultivated and Wild Hosts With Invariant Viral Consensus Sequences

Geminiviruses (family Geminiviridae) possess single-stranded circular DNA genomes that are replicated by cellular polymerases in plant host cell nuclei. In their hosts, geminivirus populations behave as ensembles of mutant and recombinant genomes, known as viral quasispecies. This favors the emergence of new geminiviruses with altered host range, facilitating new or more severe diseases or overcoming resistance traits. In warm and temperate areas several whitefly-transmitted geminiviruses of the genus Begomovirus cause the tomato yellow leaf curl disease (TYLCD) with significant economic consequences. TYLCD is frequently controlled in commercial tomatoes by using the dominant Ty-1 resistance gene. Over a 45 day period we have studied the diversification of three begomoviruses causing TYLCD: tomato yellow leaf curl virus (TYLCV), tomato yellow leaf curl Sardinia virus (TYLCSV) and tomato yellow leaf curl Malaga virus (TYLCMaV, a natural recombinant between TYLCV and TYLCSV). Viral quasispecies resulting from inoculation of geminivirus infectious clones were examined in plants of susceptible tomato (ty-1/ty-1), heterozygous resistant tomato (Ty-1/ty-1), common bean, and the wild reservoir Solanum nigrum. Differences in virus fitness across hosts were observed while viral consensus sequences remained invariant. However, the complexity and heterogeneity of the quasispecies were high, especially in common bean and the wild host. Interestingly, the presence or absence of the Ty-1 allele in tomato did not lead to differences in begomovirus mutant spectra. However, the fitness decrease of TYLCSV and TYLCV in tomato at 45 dpi might be related to an increase in CP (Coat protein) mutation frequency. In Solanum nigrum the recombinant TYLCMaV, which showed lower fitness than TYLCSV, at 45 dpi actively explored Rep (Replication associated protein) ORF but not the overlapping C4. Our results underline the importance of begomovirus mutant spectra during infections. This is especially relevant in the wild reservoir of the viruses, which has the potential to maintain highly diverse mutant spectra without modifying their consensus sequences

Analysis of the information about Doctoral Degrees presented in the Spanish universities websites.

Globalization has intensified competition, as evidenced by the growing number of international classification systems (rankings) and the attention paid to them. Doctoral education has an international character in itself. It should promote opportunities for graduate students lo participate in these international studies. The quality and competitiveness are two of the most important issues for universities. To promote the interest of graduates to continue their education after the graduate level, it would be necessary to improve the published information of ihe doctoral programs. It should increase the visibility and provide high-quality, easily accessible and comparable information which includes all the relevant aspects of these programs. The authors analysed the website contents of doctoral programs, it was observed a lack of quality of them and very poor information about the contents, so that it was decided that any of them could constitute a model for creating new websites. The recommendations on the format and contents in the web were made by a discussion group. They recommended an attractive design; a page with easy access to contents and easy to find on Ihe net and with the information in more than one language. It should include complete program and academic staff information. It should also be included the study's results which should be easily accessible and includes quantitative data, such as number of students who completed scholars, publications, research projects, average duration of the studies, etc. It will facilitate the choice of progra