High-Resolution NMR Spectroscopy at Large Fields with Nitrogen Vacancy Centers

Ensembles of nitrogen-vacancy (NV) centers are used as sensors to detect NMR signals from micron-sized samples at room temperature. In this scenario, the regime of large magnetic fields is especially interesting as it leads to a large nuclear thermal polarisation -- thus, to a strong sensor response even in low concentration samples -- while chemical shifts and J-couplings become more accessible. Nevertheless, this regime remains largely unexplored owing to the difficulties to couple NV-based sensors with high-frequency nuclear signals. In this work, we circumvent this problem with a method that maps the relevant energy shifts in the amplitude of an induced nuclear spin signal that is subsequently transferred to the sensor. This stage is interspersed with free-precession periods of the sample nuclear spins where the sensor does not participate. Thus, our method leads to high spectral resolutions ultimately limited by the coherence of the nuclear spin signal.Comment: 6 pages, 3 figure

Palinología del paleolítico medio y superior de Cova Beneito (Muro, Alicante)

Es presenten els resultats pal.linológics de una secció estratigrafica que correspon al paleolltic superior de la Cova Beneito (Muro, Alacant), la qual completa la seqüencia paleolítica que ara inclou nivells musterians, aurinyacians, solutrians, gravetians i solutreo-gravetians. La secció pol.linífera s'hi tmba escassament a 1-2 m d'una altra estudiada anterionnent, la qual va resultar esteril. Els espectres pol.línics mostren que el paleolltic superior de la zona es va desenvolupar en condicions d’aridesa ambiental prou marcades, la qual cosa està en corrodància amb les dades que s'observen a altres diagrames pol.linics per a l'estadi isotbpic 2 en domini continental. Dins d'un context global, la seqüencia de la Cova Beneito dóna suport a la hipòtesi que durant l'intetpleniglacial wunnià es produrien expansions, no necessàriament, coetànies, de nuclis de vegetació mediterrània, l'amplitud i duració de les quals dependrien de les condicions locals.In this study, the palynology of an Upper Paleolithic stratigraphical section from Cova Beneito (Muro, Alicante) is presented. It completes all the Paleolithic record including Mousterian, Aurignacian, Solutrian, Gravettian and Solutreo Gravenian industries. The polliniferous section is placed 1-2 m apart from a former one which became sterile. According to the pollen spectra, the Upper Paleolithic environment could have been one of severe aridity. This agrees with the conventional palynology in continental domain for the isotopic stage 2. Overall, the Beneito pollen record supports the view that, during the middle last glacial stage, Mediterranean vegetation couM have been widespread, but with the response of vegetation to the climatic change largely depending on local conditions.Se presentan los resultados palinológicos de una sección estratigráfica correspondiente al Paleolítico superior de Cova Beneito (Muro, Alicante), completando así la secuencia paleolítica que ahora incluye niveles musterienses, auriñacienses. solutrenses, gravetienses y solutreo-gravetienses. La sección polinífera se halla apenas a 1-2 m de otra estudiada anteriormente, la cual resultó estéril. Los espectros polínicos muestran que el Paleolítico Superior de la zona se desarrolló en condiciones de aridez ambiental bastante marcadas, lo cual concuerda con los datos que se manejan en otros diagramas polínicos para el estadio isotópico 2 en dominio continental. En un contexto global, la secuencia de Cova Beneito sirve de apoyo a la hipótesis de que durante el interpleniglacial wurmiense se produjeron expansiones, no necesariamente coetáneas, de núcleos de vegetación mediterránea cuya amplitud y duración dependerían de las condiciones locales

Tailored Ion Beam for Precise Color Center Creation

We present a unitary quantum control scheme that produces a highly monochromatic ion beam from a Paul trap. Our protocol is implementable by supplying the segmented electrodes with voltages of the order of Volts, which mitigates the impact of fluctuating voltages in previous designs and leads to a low-dispersion beam of ions. Moreover, our proposal does not rely on sympathetically cooling the ions, which bypasses the need of loading different species in the trap -- namely, the propelled ion and, e.g., a $^{40}$Ca$^+$ atom able to exert sympathetic cooling -- incrementing the repetition rate of the launching procedure. Our scheme is based on an invariant operator linear in position and momentum, which enables us to control the average extraction energy and the outgoing momentum spread. In addition, we propose a sequential operation to tailor the transversal properties of the beam before the ejection to minimize the impact spot and to increase the lateral resolution of the implantation

Amplified Nanoscale Detection of Labelled Molecules via Surface Electrons on Diamond

The detection of individual molecules and their dynamics has been a long-standing challenge in the field of nanotechnology. In this work, we present a method that utilizes a nitrogen vacancy (NV) center and a dangling-bond on the diamond surface to measure the coupling between two electronic targets tagged on a macromolecule. To achieve this, we design a multi-tone dynamical decoupling sequence that leverages the strong interaction between the nitrogen vacancy center and the dangling bond. In addition, this sequence minimizes the impact of decoherence finally resulting in an increased signal-to-noise ratio. This proposal has the potential to open up new avenues for fundamental research and technological innovation in distinct areas such as biophysics and biochemistry.Comment: 9 pages, 6 figure

Faceting and structural anisotropy of nanopatterned CdO(110) layers

CdO(110) layers with a self-organized surface structure have been grown on (10math0) sapphire (m plane) substrates by metal-organic vapor phase epitaxy. The epitaxial relationships between layer and substrate have been determined and a crystallographic model that accounts for the CdO in-plane orientation, which results in a reduced lattice mismatch when the CdO[001] direction is perpendicular to the sapphire c axis, has been proposed. Although the measured lattice parameters indicate that the layers are almost fully relaxed, an anisotropic mosaicity is detected with symmetrical rocking curves attaining minimum values when measured along the CdO[math10] direction. The layer morphology consists of a regular ridge-and-valley structure which defines, again, a preferential in-plane direction. The grooves run parallel to the CdO[001] axis and exhibit lateral surfaces sloped at 28° with respect to the (110) surface. The influence of growth temperature and VI∕II molar ratio on the anisotropic mosaicity and morphology has been [email protected] [email protected] [email protected]

Isotopic study of the influence of oxygen interaction and surface species over different catalysts on the soot removal mechanism

In order to improve the catalytic formulations for soot removal in after-treatment emission control technologies for gasoline and diesel engine vehicle, an isotopic study was approached using transitory labeled oxygen response method over model catalysts that allows the unraveling of soot oxidation mechanism. Ce-based materials promote oxygen exchange associated with the high population of lattice oxygen species (O2-) denoted as OI type. The incorporation of praseodymium produces a Pr3+ enrichment that decrease the energy for oxygen release and increase oxygen mobility through surface and subsurface oxygen centers (OII type) depending on the synthesis procedure. For PtBaK catalyst, OIII species are responsible for oxygen exchange. Gas-solid reaction between soot and gas phase molecular oxygen is responsible for direct uncatalyzed soot oxidation. For ceria containing catalysts, low-temperature soot removal takes place through the intervention of lattice atomic species and superoxide species. For DPNR model catalyst, PtBaK/Al2O3, the soot elimination occurs with the intervention OIII type centers. In the presence NO, the assisted and cooperative mechanism due to NO2 and the intervention of the adsorbed nitrate species on the trimetallic catalyst enhances soot removal capacity.MCR acknowledges the postdoctoral fellowship obtained from the University of Malaga. MCR, CH, MAL and LJA want to thank the financial support of CTQ 2017-87909R project. MCR also want to thank the University of Alicante for the financial support for the internship (INV19-07). JCMM and AGG gratefully acknowledge the financial support of Generalitat Valenciana (PROMETEO/2018/076 project) and the Spanish Ministry of Science, Innovation and Universities (PID2019-105542RB-I00 project) and the UE-FEDER funding. JCMM also acknowledges Spanish Ministry of Science, Innovation and Universities for the financial support through a FPU grant (FPU17/00603)

Unraveling the nature of active sites onto copper/ceria-zirconia catalysts for low temperature CO oxidation

The aim of this research is an attempt to shed some light on the understanding of the nature of the active sites and the generated synergies in the copper/ceria-zirconia formulations for low temperature CO oxidation by means of the creation of copper entities with different physico-chemical nature. For this reason, several CuOx/ceria-zirconia catalysts, with different Cu contents and different methods to incorporate copper species, were synthesized. Focus was specially put in this case trying to link the results of CO oxidation catalytic tests with the CO-temperature programmed reduction profiles/approximate estimations and selected characterization parameters in order to find out correlations among catalysts' properties/reducibility and catalytic behaviors, especially those corresponding to the nature and roles of the different CuOx species in contact with ceria-based support on catalytic activity. Results reveal a significant improvement in CO conversion compared to the ceria-zirconia support by adding a small amount of copper loading (as low as 0.5 %), emphasizing the paramount role of copper incorporated by the method of IWI. From 0.5 up to 2% of copper loading, an interesting increase gradual trend in activity and reducibility can be noted. It should be mentioned that all the catalysts obtained by this procedure are more catalytically active towards CO oxidation than 1%Pt/Al2O3 at low temperatures (T < 130 degrees C). CO-TPR results show that the reducibility of these catalysts is in line with their CO oxidation activity. The method of preparation has been revealed as a critical variable in the catalytic performance, and quite similar catalytic activities can be reached from different synthesis methods and different copper contents, due to the similar nature and type of CuOx species generated over the catalysts' surface, identified by the CO-TPR profiles and the rest of characterization data. Finally, IWI method seems to be the best one among those tested, thus combining superior areas of both alpha and beta contributions assigned on CO-TPR profiles, which seem to be critical in the interpretation of the catalytic behaviors

Sacroiliac joint dysfunction: reliability and validity of diagnostic test. Review

Introducción: Los test de diagnóstico de la articulación sacroiliaca son una de las herramientas más utilizadas por los fisioterapeutas para el análisis de esta articulación. El análisis de la fiabilidad y la validez de los tests de uso más extendido como son el test de flexión en bipedestación y sedestación y el test de Gillet, ha sido objetivo de múltiples investigaciones que han pretendido comprobar si su uso resulta indicado o no. Objetivo: Analizar mediante una revisión bibliográfica la fiabilidad y la validez de estos test según los trabajos existentes. Material y método: Búsquedas bibliográficas en Pubmed, Cochrane Plus y PEDro. Para el análisis de la fiabilidad se analizaron trabajos centrados en el estudio intra e inter-examinadores y para la validez, estudios que comparan estos test con un estandar de referencia. Resultados: En la búsqueda se obtienen 31 artículos y 9 manuales de Osteopatía. 14 artículos referentes a la fiabilidad de los test de diagnóstico de la articulación sacroiliaca y 16 sobre la validez. Conclusiones: No se puede confiar en los test de diagnóstico de disfunción sacroiliaca como método de diagnóstico de forma individual. Sólo el uso de varios test de diagnósticos utilizados en grupo, obtienen datos más seguros. En cuanto al análisis de la validez, el estandar de referencia más utilizado genera muchas dudas sobre su idoneidad.Terapia y Rehabilitació