105 research outputs found
Optomechanical control of molecular motors
The majority of mechanisms that can be deployed for optical micromanipulation are not especially amenable for extension into the nanoscale. At the molecular level, the rich variety of schemes that have been proposed to achieve mechanical effect using light commonly exploit specific chemical structures; familiar examples are compounds that can fold by cis-trans isomerization, or the mechanically interlocked architectures of rotaxanes. However, such systems are synthetically highly challenging, and few of them can realistically form the basis for a true molecular motor. Developing the basis for a very different strategy based on programmed electronic excitation, this paper explores the possibility of producing controlled mechanical motion through optically induced modifications of intermolecular force fields, not involving the limitations associated with using photochemical change, nor the high intensities required to produce and manipulate optical binding forces between molecules. Calculations reveal that significant, rapidly responsive effects can be achieved in relatively simple systems. By the use of suitable laser pulse sequences, the possibilities include the generation of continuous rotary motion, the ultimate aim of molecular motor design
Emissions of Fe(II) and its kinetic of oxidation at Tagoro submarine volcano, El Hierro
The eruptive process that took place in October 2011 in the submarine volcano Tagoro off the Island of El Hierro
and the subsequent degasification stage, five months later, have increased the concentration of TdFe(II) (Total
dissolved iron(II)) in thewaters nearest to the volcanic edifice. In order to detect any variation in concentrations
of TdFe(II) due to hydrothermal emissions, three cruiseswere carried out two years after the eruptive process in
October 2013,March 2014 andMay 2015. The results fromthese cruises confirmed important positive anomalies
in TdFe(II), which coincided with negatives anomalies in pHF,is (pH in free scale, at in situ conditions) located in
the proximity of themain cone. Maximumvalues in TdFe(II) both at the surface, associated to chlorophyll a maximum,
and at the sea bottom, were also observed, showing the important influence of organic complexation and
particle re-suspension processes. Temporal variability studies were carried out over periods ranging from hours
to days in the stations located over themain and two secondary cones in the volcanic edifice with positive anomalies
in TdFe(II) concentrations and negative anomalies in pHF,is values. Observations showed an important variability
in both pHF,is and TdFe(II) concentrations, which indicated the volcanic area was affected by a
degasification process that remained in the volcano after the eruptive phase had ceased. Fe(II) oxidation kinetic
studies were also undertaken in order to analyze the effects of the seawater properties in the proximities of the
volcano on the oxidation rate constants and t1/2 (half-life time) of ferrous iron. The increased TdFe(II) concentrations
and the low associated pHF,is values acted as an important fertilization event in the seawater around the
Tagoro volcano at the Island of El Hierro providing optimal conditions for the regeneration of the area.En prens
Magnetic anomalies of the NW Iberian continental margin and the adjacent abyssal plains
The NW Iberian margin is a hyperextended continental margin, formed during the opening of the North Atlantic Ocean, where a subsequent partial tectonic inversion has undergone during the Alpine Orogeny. This succession of tectonic episodes determines the magnetic signature of the margin. The Spanish Exclusive Economic Zone Project has carried out seven one-month cruises between 2001 and 2009. To extend and densify the spatial coverage, we have used data from the World Digital Magnetic Anomaly Map. Here, we describe the methodology used for the acquisition and data processing of the magnetic field data. The use of diverse instrumentation, a non-complete external field’s cancelation, and the use of different magnetic core field models, contributed to the total error budget. To reduce it, we have used a leveling algorithm which minimizes all these contributions. Finally, a statistical analysis was applied using crossover residuals, showing a resolution better than 28 nT
Evolución de la Biomecánica Deportiva a partir de las tesis doctorales realizadas en España entre los años 1980 y 2019
El objeto de este estudio es realizar una revisión de las tesis doctorales que se han leído en España en el campo de la Biomecánica Deportiva durante el periodo comprendido entre 1980 y 2019 para conocer la producción científica, los datos de autoría y dirección, y los referentes institucionales que les han dado cobertura académica. La muestra ha quedado compuesta de 233 tesis después de un proceso de selección con el uso de criterios de inclusión/exclusión y términos de búsqueda específicos. Los resultados ponen de manifiesto que la producción de tesis en Biomecánica deportiva ha sido exponencial a lo largo de los periodos analizados. El 90,6% de las tesis se han leído en universidades públicas y el 9,4% en privadas. Tanto en la autoría, como en la dirección de las tesis, existe una presencia mayoritaria de hombres. A pesar de la progresiva y creciente presencia de la mujer como autoras de las tesis, el 69,5% están realizadas por hombres y en el caso de la dirección de las tesis, la presencia de la mujer es incluso, más reducida, con un 81,5% de las tesis dirigidas solo por hombresPeer Reviewe
Estudio sísmico de la corteza superior en Isla Decepción (Antártida)
In this work, results from 4 refraction/wide angle seismic profiles, acquired in 2002 during the GEODEC-MAR cruise across Deception Island volcanic interior; have allowed us to determine the upper crustal structure. According to P-wave velocity-depth model obtained, a four layer structure have been observed. The first and the second layers correspond to the sedimentary cover (1.8-2.8 and 3.5-3.6 km s'1 respectively). The third one is interpreted as the crystalline basement (4.0-4.9 km s'1). The fourth layer is separated in two zones which indicate two types of crust: type 1-5.5 km s type 11-6.0 km s'1, the contact between both zones could be related with a fracture zone across Deception Island
The natural ocean acidification and fertilization event caused by the submarine eruption of El Hierro
Versión del edito
Significant Release of Dissolved Inorganic Nutrients From the Shallow Submarine Volcano Tagoro (Canary Islands) Based on Seven-Year Monitoring
Tagoro, the shallow submarine volcano that erupted south of El Hierro (Canary Islands, Spain) in October 2011, has been intensely monitored for over 7 years, from the early eruptive stage to the current degassing stage characterized by moderate hydrothermal activity. Here, we present a detailed study of the emissions of inorganic macronutrients (NO2– + NO3–, PO4, and Si(OH)4) comprising a dataset of over 3300 samples collected through three different sampling methodologies. Our results show a significant nutrient enrichment throughout the whole studied period, up to 8.8-fold (nitrate), 4.0-fold (phosphate), and 16.3-fold (silicate) in the water column, and larger enrichments of phosphate (10.5-fold) and silicate (325.4-fold), but not of nitrate, in the samples collected directly from the vents. We also provide some preliminary results showing ammonium (NH4+) concentrations up to 1.97 μM in the vent fluids as compared to 0.02 μM in the surrounding waters. Nutrient fluxes from the volcano during the degassing stage were estimated as 3.19 ± 1.17 mol m–2 year–1 (NO2– + NO3–), 0.02 ± 0.01 mol m–2 year–1 (PO4), and 0.60 ± 1.35 mol m–2 year–1 (Si(OH)4), comparable to other important nutrient sources in the region such as fluxes from the NW-African upwelling. Nutrient ratios were affected, with a minimum (NO3– + NO2–):PO4 ratio of 2.36:1; moreover, a linear correlation between silicate and temperature enabled the use of this nutrient as a mixing tracer. This study sheds light on how shallow hydrothermal systems impact the nutrient-poor upper waters of the ocean.En prens
Curie temperature enhancement of electron doped SrFeMoO perovskites studied by photoemission spectroscopy
We report here on the electronic structure of electron-doped half-metallic
ferromagnetic perovskites such SrLaFeMoO (=0-0.6) as
obtained from high-resolved valence-band photoemission spectroscopy (PES). By
comparing the PES spectra with band structure calculations, a distinctive peak
at the Fermi level (E) with predominantly (Fe+Mo) t
character has been evidenced for all samples, irrespectively of the values
investigated. Moreover, we show that the electron doping due to the La
substitution provides selectively delocalized carriers to the
t metallic spin channel. Consequently, a gradual rising of
the density of states at the E has been observed as a function of the La
doping. By changing the incoming photon energy we have shown that electron
doping mainly rises the density of states of Mo parentage. These findings
provide fundamental clues for understanding the origin of ferromagnetism in
these oxides and shall be of relevance for tailoring oxides having still higher
T
Chronic lymphocytic leukemia patients with IGH translocations are characterized by a distinct genetic landscape with prognostic implications
Chromosome 14q32 rearrangements/translocations involving the immunoglobulin heavy chain (IGH) are rarely detected in chronic lymphocytic leukemia (CLL). The prognostic significance of the IGH translocation is controversial and its mutational profile remains unknown. Here, we present for the first time a comprehensive next-generation sequencing (NGS) analysis of 46 CLL patients with IGH rearrangement (IGHR-CLLs) and we demonstrate that IGHR-CLLs have a distinct mutational profile with recurrent mutations in NOTCH1, IGLL5, POT1, BCL2, FBXW7, ZMYM3, MGA, BRAF and HIST1H1E genes. Interestingly, BCL2 and FBXW7 mutations were significantly associated with this subgroup and almost half of BCL2, IGLL5 and HISTH1E mutations reported were previously identified in non-Hodgkin lymphomas. Notably, IGH/BCL2 rearrangements were associated with a lower mutation frequency and carried BCL2 and IGLL5 mutations, while the other IGHR-CLLs had mutations in genes related to poor prognosis (NOTCH1, SF3B1 and TP53) and shorter time to first treatment (TFT). Moreover, IGHR-CLLs patients showed a shorter TFT than CLL patients carrying 13q-, normal fluorescence in situ hybridization (FISH) and +12 CLL, being this prognosis particularly poor when NOTCH1, SF3B1, TP53, BIRC3 and BRAF were also mutated. The presence of these mutations not only was an independent risk factor within IGHR-CLLs, but also refined the prognosis of low-risk cytogenetic patients (13q-/normal FISH). Hence, our study demonstrates that IGHR-CLLs have a distinct mutational profile from the majority of CLLs and highlights the relevance of incorporating NGS and the status of IGH by FISH analysis to refine the risk-stratification CLL model
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