Thermal vapor sulfurization of molybdenum layers

Sulfurization of molybdenum layers is a promising route for obtaining large-scale and high-quality transition metal dichalcogenides. Here we describe the synthesis of continuous and homogeneous MoS2 in the centimeter scale by the thermal vapor sulfurization of pre-deposited molybdenum precursors on SiO2. Metallic molybdenum as well as MoO3 were used as precursors while the sulfurization was performed by chemical vapor deposition. A multi-technique characterization was employed to fully describe the deposition of molybdenum as well as its sulfurization. Thus, Raman spectroscopy, X-ray and ultra-violet photoelectron spectroscopies as well as scanning electron and atomic force microscopies indicated that the molybdenum layers were completely transformed in MoS2. The samples were homogeneous in the centimeter scale and quite flat with a root mean square roughness of 1.4 Å. Furthermore, its work function was 4.1 eV.publishe

Caracterización botánica de mieles argentinas

XV lnternational A.P.L.E. Symposium of Palynolog

Túneles en la ciudad de La Plata: posibilidades de uso turístico

La presente tesis buscará determinar si la puesta en valor y acondicionamiento de los túneles descubiertos hasta el momento en la ciudad de La Plata, permitirá ampliar los circuitos de turismo cultural para que puedan ser apreciados por diferentes públicos. Se entiende por túnel a las galerías subterráneas que sirven como vía de comunicación entre dos puntos. Los mismos han existido desde la antigüedad en diferentes ciudades del mundo como vías de escape o formas de protección ante posibles amenazas. Este es el caso, por ejemplo, de la “Manzana de las Luces” en la Ciudad Autónoma de Buenos Aires, donde se pueden apreciar los túneles que conectaban subterráneamente diferentes dependencias oficiales. (Reynal 1998). La Ciudad de La Plata y su fundación han estado desde siempre rodeadas de mitos y misterios, que han dado motivo a diferentes publicaciones literarias e históricas. (Diario Hoy 6 de Noviembre de 2009). Dentro de estos mitos se incluye el de la existencia de túneles que deberían ser investigados. (Reynal 1998).Facultad de Ciencias Económica

X-ray photoelectron spectroscopy: a surface characterization technique

During the last years, an increasing number of students have visited the XPS laboratory for characterizing their samples with this experimental technique. Their background span over a wide range of fields such as physics, material science, chemistry and biology, among others. For most of them, both XPS and ultra-high vacuum technology were something new and they needed help to deal with the data of their samples. This book tries to concentrate the key information that a young researcher needs for a first approach to XPS. We hope the students will understand its working principle and will obtain the basic tools for analysing their data.publishe

Coronary Endothelium‐Dependent Vasomotor Function After Drug‐Eluting Stent and Bioresorbable Scaffold Implantation

Infarto de miocardio; Disfunción endotelial; Tomografía de coherencia ópticaMyocardial infarction; Endothelial dysfunction; Optical coherence tomographyInfart de miocardi; Disfunció endotelial; Tomografia de coherència òpticaBackground Early generation drug‐eluting stents (DESs) showed a high grade of coronary endothelial dysfunction that was attributed to lack of stent reendothelialization. Endothelium‐dependent vasomotor response of current DESs and bioresorbable scaffolds (BRSs) remains unknown. This study sought to assess the device‐related endothelial function of current devices and to correlate neointima healing with endothelial function. Methods and Results A total of 206 patients from 4 randomized trials treated with the durable‐polymer everolimus‐eluting Xience (n=44), bioresorbable‐polymer sirolimus‐eluting Orsiro (n=35), polymer‐free biolimus‐eluting Biofreedom (n=24), bioactive endothelial‐progenitor cell‐capturing sirolimus‐eluting Combo DES (n=25), polymer‐based everolimus‐eluting Absorb (n=44), and Mg‐based sirolimus‐eluting Magmaris BRS (n=34) underwent endothelium‐dependent vasomotor tests and optical coherence tomography imaging, as per protocol, at follow‐up. Crude vasomotor responses of distal segments to low‐dose acetylcholine (10−6 mol/L) were different between groups: bioresorbablepolymer DEShad the worst (−8.4%±12.6%) and durable‐polymer DES had the most physiologic (−0.4%±11.8%; P=0.014). High‐dose acetylcholine (10−4 mol/L) showed similar responses between groups (ranging from −10.8%±11.6% to −18.1%±15.4%; P=0.229). Device healing was different between devices. Uncovered struts ranged from 6.3%±7.1% (bioresorbable‐polymer DES) to 2.5%±4.5% (bioactive DES; P=0.056). In multivariate models, endothelium‐dependent vasomotor response was associated with age, bioresorbable‐polymer DES, and angiographic lumen loss, but not with strut coverage nor plaque type. Endothelial dysfunction (defined as ≥4% vasoconstriction) was observed in 46.6% of patients with low‐dose and 68.9% with high‐dose acetylcholine, without differences between groups. Conclusions At follow‐up, endothelial dysfunction was frequently observed in distal segments treated with current stents without remarkable differences between devices. Although neointima healing was different between devices, poor healing was not associated with endothelial dysfunction.The source funding of the 4 randomized trials included in this study is the following. The BVS‐FLOW trial (Coronary vasomotor function and myocardial flow with bioresorbable vascular scaffolds or everolimus‐eluting metallic stents: a randomised trial) was funded by a grant of “La Marato” Foundation. The Spanish Heart Foundation funded the RE‐TROFI2 (Long‐Term Coronary Functional Assessment of the Infarct‐Related Artery Treated With Everolimus‐Eluting Bioresorbable Scaffolds or Everolimus‐Eluting Metallic Stents: Insights of the TROFI II Trial) and MAGSTEMI (Magnesium‐Based Resorbable Scaffold Versus Permanent Metallic Sirolimus‐Eluting Stent in Patients With ST‐Segment Elevation Myocardial Infarction) trials. The FUNCOMBO (Coronary endothelial and microvascular function distal to polymer‐free and endothelial cell‐capturing drug‐eluting stents) trial was funded by OrbusNeich and was promoted by the Spanish Heart Foundation

Usefulness of the Hybrid RFR-FFR Approach: Results of a Prospective and Multicenter Analysis of Diagnostic Agreement between RFR and FFR—The RECOPA (REsting Full-Cycle Ratio Comparation versus Fractional Flow Reserve (A Prospective Validation)) Study

Cardiologia; Estudi fisiològic; EspanyaCardiología; Estudio fisiológico; EspañaCardiology; Physiological study; SpainBackground. The resting full‐cycle ratio (RFR) is a novel resting index which in contrast to the gold standard (fractional flow reserve (FFR)) does not require maximum hyperemia induction. The objectives of this study were to evaluate the agreement between RFR and FFR with the currently recommended thresholds and to design a hybrid RFR-FFR ischemia detection strategy, allowing a reduction of coronary vasodilator use. Materials and Methods. Patients subjected to invasive physiological study in 9 Spanish centers were prospectively recruited between April 2019 and March 2020. Sensitivity and specificity studies were made to assess diagnostic accuracy between the recommended levels of RFR ≤0.89 and FFR ≤0.80 (primary objective) and to determine the RFR “grey zone” in order to define a hybrid strategy with FFR affording 95% global agreement compared with FFR alone (secondary objective). Results. A total of 380 lesions were evaluated in 311 patients. Significant correlation was observed (R2 = 0.81; ) between the two techniques, with 79% agreement between RFR ≤ 0.89 and FFR ≤ 0.80 (positive predictive value, 68%, and negative predictive value, 80%). The hybrid RFR-FFR strategy, administering only adenosine in the “grey zone” (RFR: 0.86 to 0.92), exhibited an agreement of over 95% with FFR, with high predictive values (positive predictive value, 91%, and negative predictive value, 92%), reducing the need for vasodilators by 58%. Conclusions. Dichotomous agreement between RFR and FFR with the recommended thresholds is significant but limited. The adoption of a hybrid RFR-FFR strategy affords very high agreement, with minimization of vasodilator use

Graphene Based Sensors for Air Quality Monitoring - Preliminary Development Evaluation

Indoor air pollution can induce adverse health effects on building occupants and pose a significant role in health worldwide. To avoid such effects, it is extremely important to monitor and control common indoor pollutants such as CO2, VOCs and relative humidity. Therefore, this work focuses on recent advances in the field of graphene-based gas sensors, emphasizing the use of modified graphene that broadly expands the range of nanomaterials sensors. Graphene films were grown on copper by chemical vapor deposition (CVD) and transferred to arbitrary substrates. After synthesis, the samples were functionalized with Al2O3 by ALD and characterized by a large set of experimental techniques such as XPS, Raman and SEM. The results demonstrated that graphene was successfully synthesized and transferred to SiO2, glass and polymer. As a proof-of-concept, ALD of Al2O3 was performed on the graphene surface to produce a graphene/metal oxide nanostructure towards the development of nanocomposites for gas sensing. From this perspective, a laboratory prototype device based in measuring the electrical properties of the graphene sample as a function of the gas absorption is under development

Reductive nanometric patterning of graphene oxide paper using electron beam lithography

Electron beam lithography (EBL) was used for preparing nanostructured reduced patterns on the GO paper surface, while preserving its mechanical resistance and flexibility. Different EBL parameters, like dose and time of exposure for patterning were tested. SEM analysis showed the consequent increase of contrast of the reduced stripes on the patterned regions due to the increase of electron beam doses. Moreover, surface potential microscopy experiments also exhibited a clear contrast between the patterned and non-patterned regions. Structural analysis of the patterned paper through X-ray diffraction and nanoindentation showed that the interlayer distance between GO sheets decreases after reduction allowing the increase of the Hardness and Young modulus that makes this material able to be manipulated and integrated on different devices. Furthermore, we also observe that exposed areas to electron beam reduction process show an increase in the electrical conductivity up to 3 × 104 times. The developed flexible GO films can have interesting applications such as biosensors or templates for inducing tissue regeneration, by providing a surface with differently patterned cues with contrasting electron mobility. Preliminary in vitro studies with L929 fibroblasts support the cytocompatible nature of this patterned GO paper.Gil Gonçalves thanks the Fundação para a Ciência e a Tecnologia for the PostDoc grant (SFRH/BDP/84419/2012). P.A.A.P.M. acknowledge the FCT/MCTES for a research contract under the Program Investigator 2013 (IF/00917/2013/CP1162/CT0016) and TEMA – Centre for Mechanical Technology and Automation (UID/EMS/00481/2013), financed by national funds through the FCT/MEC. I.B. wish to acknowledge the Portuguese Foundation for Science and Technology for the financial support (grant IF/00582/2015). H·I·S.N. acknowledges CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. The biological studies of this work have been funded by the Ministerio de Economía y Competitividad and the Fondo Europeo de Desarrollo Regional (MAT2016-78857-R, MINECO/FEDER, UE). AGM and MCS acknowledge ISCIII-MINECO-FEDER for respective contracts. Authors would like to thank Dr M. Teresa Portolés from the Biochemistry and Molecular Biology Department at Universidad Complutense de Madrid for the generous supply of L929 fibroblasts. Dr José Ángel Rodríguez and Dr Javier Mazarío from the Service of Microscopy and Image Analysis at the Hospital Nacional de Parapléjicos are acknowledged for assistance with CLSM studies and Dr Enrique Rodríguez from the Servicio Interdepartamental de Investigación at the Universidad Autónoma de Madrid for SEM studies.info:eu-repo/semantics/acceptedVersio

On-surface self-organization of a robust metal-organic cluster based on copper(i) with chloride and organosulphur ligands

Direct sublimation of a Cu4Cl4 metal-organic cluster on Cu(110) under ultra-high vacuum allows the formation of ultra-large well-organized metal-organic supramolecular wires. Our results show that the large monomers assemble with each other by π-π interactions connecting dipyrimidine units and are stabilized by the surfaceWe thank Spanish MINECO (Grants: MAT2013-46753-C2-1-P, MAT2013-47878-C2-1-R and MAT2011-26534) for financial support. JIM acknowledges a CSIC-JaeDoc fellowship, cofunded by ES

Chemistry below graphene: Decoupling epitaxial graphene from metals by potential-controlled electrochemical oxidation

While high-quality defect-free epitaxial graphene can be efficiently grown on metal substrates, strong interaction with the supporting metal quenches its outstanding properties. Thus, protocols to transfer graphene to insulating substrates are obligatory, and these often severely impair graphene properties by the introduction of structural or chemical defects. Here we describe a simple and easily scalable general methodology to structurally and electronically decouple epitaxial graphene from Pt(111) and Ir(111) metal surfaces. A multi-technique characterization combined with ab-initio calculations was employed to fully explain the different steps involved in the process. It was shown that, after a controlled electrochemical oxidation process, a single-atom thick metal-hydroxide layer intercalates below graphene, decoupling it from the metal substrate. This decoupling process occurs without disrupting the morphology and electronic properties of graphene. The results suggest that suitably optimized electrochemical treatments may provide effective alternatives to current transfer protocols for graphene and other 2D materials on diverse metal surfacesWe acknowledge funding from the Spanish MINECO (Grants MAT2014-54231-C4-1-P, MAT2014-54231-C4-4-P, MAT2013- 47898-C2-2-R and MAT2017-85089-C2-1-R), the EU via the ERCSynergy Program (Grant ERC-2013-SYG-610256 NANOCOSMOS), the innovation program under grant agreement No. 696656 (GrapheneCore1- Graphene-based disruptive technologies), the Comunidad Aut_onoma de Madrid (CAM) MAD2D-CM Program (S2013/ MIT-3007) and computing resources from CTI-CSIC. GOI acknowledges financial support from FCT, Ministry of Science and Technology, Portugal (Grant No. PTDC/CTM-NAN/121108/2010 and IF/ 01054/2015). EL acknowledges funding from Spanish “Consolider” project CSD2010-00024. JIM acknowledges the financial support by the “Ramón y Cajal” Program of MINECO (Grant RYC-2015-17730) and NANOCOSMO