Chiral and U(1)AU(1)_A restoration for the scalar/pseudoscalar meson nonets

We analyze the restoration pattern of the members of the scalar and pseudoscalar meson nonets under chiral $O(4)$ and $U(1)_A$ symmetries. For that purpose, we exploit QCD Ward Identities (WI), which allow one to relate susceptibilities with quark condensates, as well as susceptibility differences with meson vertices. In addition, we consider the low-energy realization of QCD provided by $U(3)$ Chiral Perturbation Theory (ChPT) at finite temperature to perform a full analysis of the different correlators involved. Our analysis suggests $U(1)_A$ partner restoration if chiral symmetry partners are also degenerated. This is also confirmed by the ChPT analysis when the light chiral limit is reached. Partner degeneration for the $I=1/2$ sector, the behavior of $I=0$ mixing and the temperature scaling of meson masses predicted by WI are also studied. Special attention is paid to the connection of our results with recent lattice analyses.Comment: 28 pages and 16 figure

Influence of Baseline Fluctuation Cancellation on Automatic Measurement of Motor Unit Action Potential Duration

The aim of this work is to analyze the influence of a method for baseline fluctuation (BLF) cancellation for electromyographic (EMG) signals on automatic methods for measurement of the motor unit action potential (MUAP) duration. These methods include four conventional automatic methods (CAMs) and a recently published wavelet transform method (WTM). A set of 182 MUAPs from 170 EMG recordings were studied. The CAMs and the WTM were applied to the MUAPs before and after applying BLF cancellation to the recordings. A gold standard of duration marker positions (GSP) ws manually established. The accuracy of each algorithm was estimated as the dfference between its positions and the GSP. Accuracies were compared for the 5 methods and for each method before and after BLF cancellation. A significant difference between accuracy pre- and post-BLF removal was found in two CAMs; markers were closer to the GSP after BLF removal. For all MUAPs, the differences between WTM markers and the GSP were the smallest, and significant differences were not found for the WTM before and after BLF cancellation. The management of BLF is an important issue in EMG signal processing and BLF removal must be considered in extraction and analyse of MUAP waveforms. The BLF removal method improved the performance of two CAMs for MUAP duration measurement. The WTM was the most accurate and was not affected by BLF.

Nuevos copolímeros a base de indol

Referencia OEPM: 9300155.-- Fecha de solicitud: 28/01/1993.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).Nuevos copolímeros a base de indol (ver figura en archivo de texto adjunto). La presente invención se refiere a un nuevo tipo de copolímeros de base indol de fórmula general (I), en la que R puede ser los heterociclos tiofeno y pirrol, DP son restos del agente oxidante que actúa como agente dopante. Para la obtención de los copolímeros se hace reaccionar indol con los heterociclos tiofeno o pirrol preferentemente a temperatura entre 25-30ºC en presencia de agente oxidante tal como el cloruro férrico, disueltos en cloroformo. En ambos casos se utilizan distintas relaciones molares de oxidante/monómero entre 1.5 y 5 y de comonómero/indol entre 1.5 y 9. Al final de la reacción se precipita el copolímero con una mezcla metanol/agua (1:1 en peso). Estos polímeros se caracterizan por presentar una marcada conductividad eléctrica y ser fácilmente solubles, lo que les hace ser aptos para diversas aplicaciones como conductores.Peer reviewe

Characterization of the response to zinc deficiency in the cyanobacterium Anabaena sp. strain PCC 7120

Zur regulators control zinc homeostasis by repressing target genes under zinc-sufficient conditions in a wide variety of bacteria. This paper describes how part of a survey of duplicated genes led to the identification of the open reading frame all2473 as the gene encoding the Zur regulator of the cyanobacterium Anabaena sp. strain PCC 7120. All2473 binds to DNA in a zinc-dependent manner, and its DNA-binding sequence was characterized, which allowed us to determine the relative contribution of particular nucleotides to Zur binding. A zur mutant was found to be impaired in the regulation of zinc homeostasis, showing sensitivity to elevated concentrations of zinc but not other metals. In an effort to characterize the Zur regulon in Anabaena, 23 genes containing upstream putative Zur-binding sequences were identified and found to be regulated by Zur. These genes are organized in six single transcriptional units and six operons, some of them containing multiple Zur-regulated promoters. The identities of genes of the Zur regulon indicate that Anabaena adapts to conditions of zinc deficiency by replacing zinc metalloproteins with paralogues that fulfill the same function but presumably with a lower zinc demand, and with inducing putative metallochaperones and membrane transport systems likely being involved in the scavenging of extracellular zinc, including plasma membrane ABC transport systems and outer membrane TonB-dependent receptors. Among the Zur-regulated genes, the ones showing the highest induction level encode proteins of the outer membrane, suggesting a primary role for components of this cell compartment in the capture of zinc cations from the extracellular medium.Ministerio de Ciencia e Innovación y Fondo Social Europeo BFU2007-66589/BMC BFU2010-19544Junta de Andalucía y FEDER P07-CVI-0316

Engineering a robust cyclohexanone monooxygenase for the production of methyl propanoate

Cyclohexanone monooxygenase (EC 1.14.13.22) from Acinetobacter calcoaceticus (AcCHMO) catalyzes the Baeyer-Villiger oxidation of 2-butanone, producing both ethyl acetate and methyl propanoate (Fig. 1A).[1] Methyl propanoate is of industrial interest as a precursor of acrylic plastic. We have replaced various residues near the substrate and NADP+ binding sites in AcCHMO using saturation mutagenesis with the aim of increasing both the activity on 2-butanone and the methyl propanoate/total product ratio. Whole cell biotransformations were prepared for the resulting libraries and the analyses were carried out by headspace GC analysis. A higher conversion yield (92%) and kcat value (0.5 s-1) than wild type AcCHMO (52% and 0.3 s-1, respectively) were observed for T56S AcCHMO. I491A AcCHMO exhibited a significant improvement over the wild type enzyme in the desired regioselectivity using 2-butanone as a substrate (40% vs. 26% methyl propanoate, respectively). The T56S/I491A double mutant combined the beneficial effects of both mutations (Fig. 1B).[2] Recently, we reported on the discovery, characterization, and crystal structure determination of a CHMO from Thermocrispum municipale (TmCHMO).[3] A Ser residue was found in TmCHMO at the equivalent position to that of AcCHMO T56. The TmCHMO I493, equivalent to AcCHMO I491, was replaced with an Ala by site-directed mutagenesis. The resulting mutant exhibited a similar activity and regioselectivity to those observed for T56S/I491A AcCHMO using the substrate 2-butanone. This study shows that even for a relatively small aliphatic substrate, regioselectivity can be tuned by structure-inspired enzyme engineering in two different CHMOs. Beneficial mutations previously carried out for AcCHMO, or other CHMOs, may be repeated in TmCHMO achieving similar effects. This is very attractive for biocatalysis since TmCHMO is significantly more thermostable and solvent tolerant than all CHMOs described so far. .Please click Additional Files below to see the full abstract

Breaking the configurational anisotropy in Fe single crystal nanomagnets

In this work, we improve the ability to tailor the switching mechanism in nanomagnets by introducing an additional, highly controlled source of anisotropy: magnetocrystalline anisotropy. We analyze the vortex dynamics in single crystal Fe nanotriangles with different orientations of the crystalline axes. By experimental studies and simulation, we show that the angular dependence of the vortex annihilation field springs from the convolution of the crystalline and configurational anisotropies. In contrast, the remanence and the nucleation field present a much simpler behavior controlled by the existence of a single symmetry axis when shape and crystalline orientation are taken into account

Astrobiological field campaign to a volcanosedimentary mars analogue methane producing subsurface protected ecosystem: Imuruk Lake (Alaska)

Viking missions reported adverse conditions for life in Mars surface. High hydrogen signal obtained by Mars orbiters has increased the interest in subsurface prospection as putative protected Mars environment with life potential. Permafrost has attracted considerable interest from an astrobiological point of view due to the recently reported results from the Mars exploration rovers. Considerable studies have been developed on extreme ecosystems and permafrost in particular, to evaluate the possibility of life on Mars and to test specific automated life detection instruments for space missions. The biodiversity of permafrost located on the Bering Land Bridge National Preserve has been studied as an example of subsurface protected niche of astrobiological interest. Different conventional (enrichment and isolation) and molecular ecology techniques (cloning, fluorescence "in situ" probe hybridization, FISH) have been used for isolation and bacterial identificationThe expedition to Imuruk Lake was supported by Centro de Astrobiología-INTA (Spain). The laboratory experimental procedures were supported by Grant AYA 2010–20213 “Desarrollo de Tecnología para la identificación de vida de forma automática” from the Spanish Governmen

The water cycle and regolith-atmosphere interaction at Gale crater, Mars

We perform mesoscale simulations of the water cycle in a region around Gale crater, including the diffusion of water vapour in and out of the regolith, and compare our results with measurements from the REMS instrument on board the Curiosity rover. Simulations are performed at three times of year, and show that diffusion in and out of the regolith and adsorption/desorption needs to be taken into account in order to match the diurnal variation of relative humidity measured by REMS. During the evening and night, local downslope flows transport water vapour down the walls of Gale crater. When including regolith-atmosphere interaction, the amount of vapour reaching the crater floor is reduced (by factors of 2–3 depending on season) due to vapour diffusing into the regolith along the crater walls. The transport of vapour into Gale crater is also affected by the regional katabatic flow over the dichotomy boundary, with the largest flux of vapour into the regolith initially occurring on the northern crater wall, and moving to the southern wall by early morning. Upslope winds during the day transport vapour desorbing and mixing out of the regolith up crater walls, where it can then be transported a few hundred metres into the atmosphere at convergence boundaries. Regolith-atmosphere interaction limits the formation of surface ice by reducing water vapour abundances in the lower atmosphere, though in some seasons ice can still form in the early morning on eastern crater walls. Subsurface ice amounts are small in all seasons, with ice only existing in the upper few millimetres of regolith during the night. The results at Gale crater are representative of the behaviour at other craters in the mesoscale domain