Giant magnetoimpedance effect in surface modified CoFeMoSiB amorphous ribbons

[EN] Thin magnetic Fe layers in thickness of 10-240 nm were deposited onto a wheel surface of CoFeMoSiB amorphous ribbons to check our concept of a new type of heterogeneous magnetoimpedance materials formed by two different magnetic parts. The presence of an additional iron layer modifies the magnetoimpedance response of the composite material and leads to increase of the magnetoimpedance ratio from 330 to 345% at a frequency of 3.5 MHz. Two possible mechanisms are discussed for explanation to the observed behaviour. Modification of the surface properties of the amorphous ribbons may have certain potential for technological applications.Cerdeira, M.; Kurlyandskaya, G.; Fernandez, A.; Tejedor, M.; García Miquel, ÁH. (2003). Giant magnetoimpedance effect in surface modified CoFeMoSiB amorphous ribbons. Chinese Physics Letters. 20(12):2246-2249. doi:10.1088/0256-307X/20/12/045S224622492012Beach, R. S., & Berkowitz, A. E. (1994). Giant magnetic field dependent impedance of amorphous FeCoSiB wire. Applied Physics Letters, 64(26), 3652-3654. doi:10.1063/1.111170Kaneo Mohri, Tsuyoshi Uchiyama, & Panina, L. V. (1997). Recent advances of micro magnetic sensors and sensing application. Sensors and Actuators A: Physical, 59(1-3), 1-8. doi:10.1016/s0924-4247(97)80141-0Vazquez, M., Kurlyandskaya, G. V., Garcia-Beneytez, J. M., Sinnecker, J. P., Barandiaran, J. M., Lukshina, V. A., & Potapov, A. P. (1999). Frequency dependence of the magnetoimpedance in nanocrystalline FeCuNbSiB with high transverse stress-induced magnetic anisotropy. IEEE Transactions on Magnetics, 35(5), 3358-3360. doi:10.1109/20.800523L.Sánchez, M., M.Prida, V., Hernando, B., V.Kurlyandskaya, G., D.Santos, J., Tejedor, M., & Vázquez, M. (2002). Magnetostriction Dependence of the Relaxation Frequency in the Magnetoimpedance Effect for Amorphous and Nanocrystalline Ribbons. Chinese Physics Letters, 19(12), 1870-1873. doi:10.1088/0256-307x/19/12/339Xiao, S., Liu, Y., Yan, S., Dai, Y., Zhang, L., & Mei, L. (2000). Giant magnetoimpedance and domain structure in FeCuNbSiB films and sandwiched films. Physical Review B, 61(8), 5734-5739. doi:10.1103/physrevb.61.5734Nishibe, Y., Yamadera, H., Ohta, N., Tsukada, K., & Nonomura, Y. (2000). Thin film magnetic field sensor utilizing Magneto Impedance effect. Sensors and Actuators A: Physical, 82(1-3), 155-160. doi:10.1016/s0924-4247(99)00327-1You-Yong, D., Shu-Qin, X., Yi-Hua, L., Lin, Z., Hou-Zheng, W., & Yan-Zhong, Z. (2001). Frequency and Field Dependences of Giant Magneto-Impedance Effect in Sandwiched FeCuCrVSiB Films. Chinese Physics Letters, 18(2), 272-274. doi:10.1088/0256-307x/18/2/340Beach, R. S., Smith, N., Platt, C. L., Jeffers, F., & Berkowitz, A. E. (1996). Magneto‐impedance effect in NiFe plated wire. Applied Physics Letters, 68(19), 2753-2755. doi:10.1063/1.115587Betancourt, I., Valenzuela, R., & Vazquez, M. (2002). Giant magnetoimpedance in Co-based microwires at low frequencies (100 Hz–13 MHz). Journal of Applied Physics, 91(10), 8423. doi:10.1063/1.1447518Iida, S., Ishii, O., & Kambe, S. (1998). Magnetic Sensor Using Second Harmonic Change in Magneto-Impedance Effect. Japanese Journal of Applied Physics, 37(Part 2, No. 7B), L869-L871. doi:10.1143/jjap.37.l869Amalou, F., & Gijs, M. A. M. (2002). Giant magnetoimpedance in trilayer structures of patterned magnetic amorphous ribbons. Applied Physics Letters, 81(9), 1654-1656. doi:10.1063/1.1499769Panina, L. ., & Mohri, K. (2000). Magneto-impedance in multilayer films. Sensors and Actuators A: Physical, 81(1-3), 71-77. doi:10.1016/s0924-4247(99)00089-8Kurlyandskaya, G. V., Yakabchuk, H., Kisker, E., Bebenin, N. G., Garcı́a-Miquel, H., Vázquez, M., & Vas’kovskiy, V. O. (2001). Very large magnetoimpedance effect in FeCoNi ferromagnetic tubes with high order magnetic anisotropy. Journal of Applied Physics, 90(12), 6280-6286. doi:10.1063/1.1418423Kurlyandskaya, G. ., Garcı́a-Miquel, H., Vázquez, M., Svalov, A. ., & Vas’kovskiy, V. . (2002). Longitudinal magnetic bistability of electroplated wires. Journal of Magnetism and Magnetic Materials, 249(1-2), 34-38. doi:10.1016/s0304-8853(02)00500-0Tejedor, M., Rubio, H., Elbaile, L., & Iglesias, R. (1993). Surface magnetic anisotropy in amorphous alloys. IEEE Transactions on Magnetics, 29(6), 3466-3468. doi:10.1109/20.281198Tejedor, M., Garcı́a, J. A., Carrizo, J., Elbaile, L., & Santos, J. D. (2002). Effect of residual stresses and surface roughness on coercive force in amorphous alloys. Journal of Applied Physics, 91(10), 8435. doi:10.1063/1.1453947Kurlyandskaya, G. V., Sánchez, M. L., Hernando, B., Prida, V. M., Gorria, P., & Tejedor, M. (2003). Giant-magnetoimpedance-based sensitive element as a model for biosensors. Applied Physics Letters, 82(18), 3053-3055. doi:10.1063/1.1571957Miyajima, H., Sato, K., & Mizoguchi, T. (1976). Simple analysis of torque measurement of magnetic thin films. Journal of Applied Physics, 47(10), 4669-4671. doi:10.1063/1.32239

Toxic elements and speciation in seafood samples from different contaminated sites in Europe

The presence of cadmium (Cd), lead (Pb), mercury (THg), methylmercury (MeHg), arsenic (TAs), inorganic arsenic (iAs), cobalt (Co), copper (Cu), zinc (Zn), nickel (Ni), chromium (Cr) and iron (Fe) was investigated in seafood collected from European marine ecosystems subjected to strong anthropogenic pressure, i.e. hotspot areas. Different species (Mytilus galloprovincialis, n=50; Chamelea gallina, n=50; Liza aurata, n=25; Platichthys flesus, n=25; Laminaria digitata, n=15; and Saccharina latissima, n=15) sampled in Tagus estuary, Po delta, Ebro delta, western Scheldt, and in the vicinities of a fish farm area (Solund, Norway), between September and December 2013, were selected to assess metal contamination and potential risks to seafood consumers, as well as to determine the suitability of ecologically distinct organisms as bioindicators in environmental monitoring studies. Species exhibited different elemental profiles, likely as a result of their ecological strategies, metabolism and levels in the environment (i.e. seawater and sediments). Higher levels of Cd (0.15–0.94 mg kg-1), Pb (0.37-0.89 mg kg-1), Co (0.48–1.1 mg kg-1), Cu (4.8–8.4 mg kg-1), Zn (75–153 mg kg-1), Cr (1.0–4.5 mg kg-1) and Fe (283–930 mg kg-1) were detected in bivalve species, particularly in M. galloprovincialis from Ebro and Po deltas, whereas the highest content of Hg was found in P. flesus (0.86 mg kg-1). In fish species, most Hg was organic (MeHg; from 69 to 79%), whereas lower proportions of MeHg were encountered in bivalve species (between 20 and 43%). The highest levels of As were found in macroalgae species L. digitata and S. latissima (41 mg kg-1 and 43 mg kg-1, respectively), with iAs accounting almost 50% of the total As content in L. digitata but not with S. latissima nor in the remaining seafood samples. This work highlights that the selection of the most appropriate bioindicator species is a fundamental step in environmental monitoring of each contaminant, especially in coastal areas. Furthermore, data clearly shows that the current risk assessment and legislation solely based on total As or Hg data is limiting, as elemental speciation greatly varies according to seafood species, thus playing a key role in human exposure assessment via food

On Imprimitive Representations of Finite Reductive Groups in Non-defining Characteristic

In this paper, we begin with the classification of Harish-Chandra imprimitive representations in non-defining characteristic. We recall the connection of this problem to certain generalizations of Iwahori-Hecke algebras and show that Harish-Chandra induction is compatible with the Morita equivalence by Bonnaf\'{e} and Rouquier, thus reducing the classification problem to quasi-isolated blocks. Afterwards, we consider imprimitivity of unipotent representations of certain classical groups. In the case of general linear and unitary groups, our reduction methods then lead to results for arbitrary Lusztig series

Bioaccessibility of contaminants of emerging concern in raw and cooked commercial seafood species: insights for food safety risk assessment.

Autoria na publicação: FABIOLA FOGAÇA

Perivascular spaces are associated with tau pathophysiology and synaptic dysfunction in early Alzheimer’s continuum

Background: Perivascular spaces (PVS) have an important role in the elimination of metabolic waste from the brain. It has been hypothesized that the enlargement of PVS (ePVS) could be affected by pathophysiological mechanisms involved in Alzheimer’s disease (AD), such as abnormal levels of CSF biomarkers. However, the relationship between ePVS and these pathophysiological mechanisms remains unknown. Objective: We aimed to investigate the association between ePVS and CSF biomarkers of several pathophysiological mechanisms for AD. We hypothesized that ePVS will be associated to CSF biomarkers early in the AD continuum (i.e., amyloid positive cognitively unimpaired individuals). Besides, we explored associations between ePVS and demographic and cardiovascular risk factors. Methods: The study included 322 middle-aged cognitively unimpaired participants from the ALFA + study, many within the Alzheimer’s continuum. NeuroToolKit and Elecsys® immunoassays were used to measure CSF Aβ42, Aβ40, p-tau and t-tau, NfL, neurogranin, TREM2, YKL40, GFAP, IL6, S100, and α-synuclein. PVS in the basal ganglia (BG) and centrum semiovale (CS) were assessed based on a validated 4-point visual rating scale. Odds ratios were calculated for associations of cardiovascular and AD risk factors with ePVS using logistic and multinomial models adjusted for relevant confounders. Models were stratified by Aβ status (positivity defined as Aβ42/40 < 0.071). Results: The degree of PVS significantly increased with age in both, BG and CS regions independently of cardiovascular risk factors. Higher levels of p-tau, t-tau, and neurogranin were significantly associated with ePVS in the CS of Aβ positive individuals, after accounting for relevant confounders. No associations were detected in the BG neither in Aβ negative participants. Conclusions: Our results support that ePVS in the CS are specifically associated with tau pathophysiology, neurodegeneration, and synaptic dysfunction in asymptomatic stages of the Alzheimer’s continuum

Spoken term detection ALBAYZIN 2014 evaluation: overview, systems, results, and discussion

The electronic version of this article is the complete one and can be found online at: http://dx.doi.org/10.1186/s13636-015-0063-8Spoken term detection (STD) aims at retrieving data from a speech repository given a textual representation of the search term. Nowadays, it is receiving much interest due to the large volume of multimedia information. STD differs from automatic speech recognition (ASR) in that ASR is interested in all the terms/words that appear in the speech data, whereas STD focuses on a selected list of search terms that must be detected within the speech data. This paper presents the systems submitted to the STD ALBAYZIN 2014 evaluation, held as a part of the ALBAYZIN 2014 evaluation campaign within the context of the IberSPEECH 2014 conference. This is the first STD evaluation that deals with Spanish language. The evaluation consists of retrieving the speech files that contain the search terms, indicating their start and end times within the appropriate speech file, along with a score value that reflects the confidence given to the detection of the search term. The evaluation is conducted on a Spanish spontaneous speech database, which comprises a set of talks from workshops and amounts to about 7 h of speech. We present the database, the evaluation metrics, the systems submitted to the evaluation, the results, and a detailed discussion. Four different research groups took part in the evaluation. Evaluation results show reasonable performance for moderate out-of-vocabulary term rate. This paper compares the systems submitted to the evaluation and makes a deep analysis based on some search term properties (term length, in-vocabulary/out-of-vocabulary terms, single-word/multi-word terms, and in-language/foreign terms).This work has been partly supported by project CMC-V2 (TEC2012-37585-C02-01) from the Spanish Ministry of Economy and Competitiveness. This research was also funded by the European Regional Development Fund, the Galician Regional Government (GRC2014/024, “Consolidation of Research Units: AtlantTIC Project” CN2012/160)

Chromatin regulation by Histone H4 acetylation at Lysine 16 during cell death and differentiation in the myeloid compartment

Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death