151 research outputs found
The role of the transient atropisomerism and chirality of flurbiprofen unveiled by laser‐ablation rotational spectroscopy
Producción CientíficaThe combination of atropisomerism and chirality in flurbiprofen is shown to be relevant concerning its pharmacological activity. The two most stable conformers of a total of eight theoretically predicted for each R- or S- flurbiprofen enantiomers have been isolated in the cooling conditions of a supersonic jet and structurally characterized by laser ablation Fourier transform microwave spectroscopy. The detected conformers, whose structure is mainly defined by three dihedral angles, only differ in the sign of the phenyl torsion angle giving rise to Sa and Ra atropisomers. A comparison with the structures available for the R- and S- enantiomers complexed to COX isoforms reveals that the enzymes select only the Saatropisomers, resulting in a diastereoisomer-specific recognition. The most stable gas phase conformer is exclusively selected when using the S- enantiomer while the second is recognized only for the R- enantiomer. These experimental results highlight the importance of atropisomerism in drug design.Junta de Castilla y León (Grant INFRARED-FEDER IR2020-1-UVa02)Ministerio de Economía y Competitividad (Grant CTQ2016-75253-P)Ministerio de Ciencia e Innovación (Grant PID2021-125207NB-C33
Stars, combs and bottlebrushes of elastic single-chain nanoparticles
Hierarchical self-assembly of structural elements gives rise to superstructures often with outstanding properties when compared to individual elements, as first observed in nature. While folding of individual synthetic chains leads to discrete single-chain nanoparticles (SCNPs) of significant interest for a number of applications, its full potential utility through integration into well-defined superstructures is recently being recognized. Remarkably, SCNPs in good solvent resemble randomly branched polymers with ideal connectivity in a theta-solvent or percolating clusters with screened excluded-volume interactions. Herein we consider the integration of SCNPs into star, comb and bottlebrush topologies and investigate the dimensions of the resulting superstructures under different conditions (good solvent, ideal conformations, 1D-and 2D-confinement in nanopores and nanoslits, anchored to flat surfaces). A detailed comparison of the equilibrium conformational properties of star, comb and bottlebrush polymers composed of elastic SCNPs to those of equivalent topologies based on linear chains is provided. This analysis reveals the effect of hierarchical topology on superstructure dimensions in several relevant environments, as well as how the structural parameters of the SCNPs influence the location of the comb-to-bottlebrush transition as a function of grafting density. The degree of intra-chain cross-linking arises as an additional parameter for controlling the local and global dimensions of stars, combs and bottlebrushes of SCNPs.Financial support by MCIN/AEI/10.13039/501100011033 and “ERDF – A way of making Europe” (PID2021-123438NB-I00), Eusko Jaurlaritza –Basque Government (IT1566-22) and Gipuzkoako Foru Aldundia, Programa Red Gipuzkoana de Ciencia, Tecnología e Innovación (2021-CIEN-000010-01) is gratefully acknowledged
Videojuegos y regulación emocional en estudiantes universitarios
La presente investigación tuvo como objetivo estudiar el efecto que tienen los videojuegos en
la reparación del estado de ánimo de estudiantes universitarios de una universidad privada de
Lima Metropolitana. Con ese fin se evaluó a 40 alumnos, 24 hombres (60%) y 16 mujeres
(40%), entre los 18 a 25 años (M = 20.35, DE = 2.06). Los instrumentos utilizados fueron la
Escala de Afecto Positivo y Negativo (SPANAS) y el Immersive Experience Questionnaire
(EIQ). Además, se utilizó una adaptación al español de The mood induction task diseñada por
Robinson, Grillon y Sahakian (2012) para inducir un estado de ánimo negativo en los
participantes. En este sentido, luego de inducir dicho estado de ánimo, el grupo experimental
jugó un videojuego, mientras que el grupo control solo descansó. Se encontraron efectos
significativos de jugar un videojuego en la reparación del estado de ánimo negativo, pero no se
encontraron diferencias significativas en esta reparación entre el grupo experimental y el grupo
control. Tampoco se encontraron relaciones con las horas de juego semanales, no había
diferencias significativas con respecto al sexo y solo se encontró una relación moderada entre
esta reparación y el área de involucramiento emocional de la inmersión.The aim of this research was to study the effect of video games on the mood repair of university
students at a private university in Metropolitan Lima. To this end, 40 students, 24 men (60%)
and 16 women (40%), aged 18 to 25 (M = 20.35, SD = 2.06) were evaluated. The instruments
used were the Positive and Negative Affect Scale (SPANAS) and the Immersive Experience
Questionnaire (EIQ). In addition, a Spanish adaptation of The mood induction task designed
by Robinson, Grillon and Sahakian (2012) was used to induce a negative mood in the
participants. In this sense, the experimental group played a video game after being induced in
this mood, while the control group only rested. Significant effects of playing a video game on
the repair of the negative mood were found, but no significant differences were found in this
repair between the experimental group and the control group. No relationship was found with
the weekly hours of play, there were no significant differences with respect to sex and only a
moderate relationship was found between this repair and the area of emotional involvement of
the immersion
Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay
The Cretaceous (Mercedes Formation) and Paleogene (Queguay Formation) deposits cropping out inWand S
Uruguay comprise two terrestrial limestone units that are very rich in trace fossils. The study of these units
permits to propose a sedimentological model for palustrine limestones and calcretes in which the distribution
of different types of trace fossils is considered. The study units include three main types of deposit: lacustrine
limestones, palustrine limestones and calcretes. The lacustrine limestones are relatively homogeneous and
contain gastropods, charophytes and ostracods, but no trace fossils. They were deposited in a relatively more
perennial lacustrine environment. The palustrine limestones include four different facies: desiccated
mudstones, nodular limestones, granular limestones and gravel-sheets. The desiccated mudstones indicate
a lesser degree of pedogenic modification and the granular limestones a higher degree. The gravel-sheets are
an indication of the reworking of previous limestones deposits during low lakewater levels. Most of the
palustrine limestones (except the gravel sheets) contain the same bioclasts as the lacustrine limestones plus a
variety of trace fossils such as Rebuffoichnus sciuttoi, Fictovichnus gobiensis and different ichnospecies of
Celliforma. The calcretes are either massive (groundwater) or laminar. The massive calcretes are sandy
limestones made up of a carbonate matrix and cements. The laminar calcretes (root mats), which contain
alveolar septal structures, occur as centimetre-thick layers and can be seen in all types of deposit. They contain
the same trace fossil association as the palustrine limestones; the massive calcretes are poorer in such fossils.
The distribution of trace fossils in these environments is under strong facies control and provides good
evidence of subaerial exposure and semi-arid climates. All the limestones are partially replaced and cemented
by opal and quartz, but in all cases the primary structure is preserved. Silicification occurred under
groundwater meteoric conditions. Overall, the limestones facies (calcretes, palustrine and lacustrine) and
their lateral distribution likely reflect the existence of wetland environments in semiarid to sub-humid
climates. These climatic conditions were interrupted by a period of increased precipitations, probably the
Early Eocene Climatic Optimum
Advances in the Phototriggered Synthesis of Single-Chain Polymer Nanoparticles
Clean use of photons from light to activate chemical reactions offers many possibilities in different fields, from chemistry and biology to materials science and medicine. This review article describes the advances carried out in last decades toward the phototriggered synthesis of single-chain polymer nanoparticles (SCNPs) as soft nanomaterials with promising applications in enzyme-mimicking catalysis and nanomedicine, among other different uses. First, we summarize some different strategies developed to synthesize SCNPs based on photoactivated intrachain homocoupling, phototriggered intrachain heterocoupling and photogenerated collapse induced by an external cross-linker. Next, we comprehensively review the emergent topic of photoactivated multifolding applied to SCNP construction. Finally, we conclude by summarizing recent strategies towards phototriggered disassembly of SCNPsThis research was funded by Gipuzkoako Foru Aldundia -Programa Red Gipuzkoana de Ciencia, Tecnologia e Innovacion 2019-, grant number 2019-CIEN-000050-01; Basque Government, grant number IT-1175-19; and MCIU/AEI/FEDER, UE, grant number PGC2018-094548-B-I00
Metamorphosis of a Commodity Plastic like PVC to Efficient Catalytic Single-Chain Nanoparticles
We perform the conversion of a commodity plastic of common use in pipes, window frames, medical devices, flexible hoses, etc. like polyvinyl chloride (PVC) to single-chain nanoparticles (SCNPs). SCNPs are versatile, protein-mimetic soft nano-objects of growing interest for catalysis, sensing, and nanomedicine, among other uses. We demonstrate that the metamorphosis process -as induced through metal-free click chemistry- leads to well-defined, uniform SCNPs that are stable during storage in the solid state for months. All the conversion process (from PVC isolation to PVC-SCNPs synthesis) can be run in a green, dipolar aprotic solvent and involving, when required, a simple mixture of ethanol and water (1/1 vol.) as non-solvent. The resulting PVC-SCNPs are investigated as recyclable, metalloenzyme-mimetic catalysts for several representative Cu(II)-catalyzed organic reactions. The method could be valid for the metamorphosis and valorization of other commodity plastics in which it is feasible to install azide functional groups in their linear polymer chains.We gratefully acknowledge Grant PID2021-123438NB-I00 funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”, Grant TED2021-130107A-I00 funded by MCIN/AEI/10.13039/501100011033 and Unión Europea “NextGenerationEU/PRTR” and Grant IT-1566-22 from Eusko Jaurlaritza (Basque Government)
Evaluating Latency in Multiprocessing Embedded Systems for the Smart Grid
Smart grid endpoints need to use two environments within a processing system (PS), one with a Linux-type operating system (OS) using the Arm Cortex-A53 cores for management tasks, and the other with a standalone execution or a real-time OS using the Arm Cortex-R5 cores. The Xen hypervisor and the OpenAMP framework allow this, but they may introduce a delay in the system, and some messages in the smart grid need a latency lower than 3 ms. In this paper, the Linux thread latencies are characterized by the Cyclictest tool. It is shown that when Xen hypervisor is used, this scenario is not suitable for the smart grid as it does not meet the 3 ms timing constraint. Then, standalone execution as the real-time part is evaluated, measuring the delay to handle an interrupt created in programmable logic (PL). The standalone application was run in A53 and R5 cores, with Xen hypervisor and OpenAMP framework. These scenarios all met the 3 ms constraint. The main contribution of the present work is the detailed characterization of each real-time execution, in order to facilitate selecting the most suitable one for each application.This work has been supported by the Ministerio de Economía y Competitividad of Spain within the project TEC2017-84011-R and FEDER funds as well as by the Department of Education of the Basque Government within the fund for research groups of the Basque university system IT978-16. It has also been supported by the Basque Government within the project HAZITEK ZE-2020/00022 as well as the Ministerio de Ciencia e Innovación of Spain through the Centro para el Desarrollo Tecnológico Industrial (CDTI) within the project IDI-20201264; in both cases, they have been financed through the Fondo Europeo de Desarrollo Regional 2014-2020 (FEDER funds). It has also been supported by the University of the Basque Country within the scholarship for training of research staff with code PIF20/135
A new record for the mycobiota of Valencia Autonomous Community: Verpa bohemica
Se trata de una especie poco frecuente, que se ha encontrado por primera vez en Alicante (España). Se aportan datos acerca de la ecología, fenología y morfología de esta especie en el territorio estudiado.An uncommon species is found for the first time in Alicante province (Spain). Some data are provided about the ecology, phenology and morphology of this species in the studied territory
Toward Long-Term-Dispersible, Metal-Free Single-Chain Nanoparticles
We report herein on a new platform for synthesizing stable, inert, and dispersible metal-free single-chain nanoparticles (SCNPs) via intramolecular metal-traceless azide–alkyne click chemistry. It is well known that SCNPs synthesized via Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) often experience metal-induced aggregation issues during storage. Moreover, the presence of metal traces limits its use in a number of potential applications. To address these problems, we selected a bifunctional cross-linker molecule, sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DIBOD). DIBOD has two highly strained alkyne bonds that allow for the synthesis of metal-free SCNPs. We demonstrate the utility of this new approach by synthesizing metal-free polystyrene (PS)-SCNPs without significant aggregation issues during storage, as demonstrated by small-angle X-ray scattering (SAXS) experiments. Notably, this method paves the way for the synthesis of long-term-dispersible, metal-free SCNPs from potentially any polymer precursor decorated with azide functional groups.We gratefully acknowledge Grant PID2021-123438NB-I00 funded by MCIN/AEI/10.13039/501100011033; “ERDF A way of making Europe”, Grant TED2021-130107A-I00 funded by MCIN/AEI/10.13039/501100011033; Unión Europea “NextGenerationEU/PRTR” and Grant IT-1566-22 from Eusko Jaurlaritza (Basque Government)
Non-quantum liquefaction of coherent gases
We show that a gas-to-liquid phase transition at zero temperature may occur
in a coherent gas of bosons in the presence of competing nonlinear effects.
This situation can take place both in atomic systems like Bose-Einstein
Condensates in alkalii gases with two and three-body interactions of opposite
signs, as well as in laser beams which propagate through optical media with
Kerr (focusing) and higher order (defocusing) nonlinear responses. The
liquefaction process takes place in absence of any quantum effect and can be
formulated in the frame of a mean field theory, in terms of the minimization of
a thermodynamic potential. We also show numerically that the effect of linear
gain and three-body recombination also provides a rich dynamics with the
emergence of self-organization behaviour.Comment: 6 pages, 5 figures. Submitted to Physica D: Nonlinear Phenomen
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