Band gaps in elastic metamaterial rods with spatial periodic distribution and periodically attached local resonators are investigated. New techniques to analyze metamaterial systems are using a ...combination of analytical or numerical method with wave propagation. One of them, called here wave spectral element method (WSEM), consists of combining the spectral element method (SEM) with Floquet–Bloch׳s theorem. A modern methodology called wave finite element method (WFEM), developed to calculate dynamic behavior in periodic acoustic and structural systems, utilizes a similar approach where SEM is substituted by the conventional finite element method (FEM). In this paper, it is proposed to use WFEM to calculate band gaps in elastic metamaterial rods with spatial periodic distribution and periodically attached local resonators of multi-degree-of-freedom (M-DOF). Simulated examples with band gaps generated by Bragg scattering and local resonators are calculated by WFEM and verified with WSEM, which is used as a reference method. Results are presented in the form of attenuation constant, vibration transmittance and frequency response function (FRF). For all cases, WFEM and WSEM results are in agreement, provided that the number of elements used in WFEM is sufficient to convergence. An experimental test was conducted with a real elastic metamaterial rod, manufactured with plastic in a 3D printer, without local resonance-type effect. The experimental results for the metamaterial rod with band gaps generated by Bragg scattering are compared with the simulated ones. Both numerical methods (WSEM and WFEM) can localize the band gap position and width very close to the experimental results. A hybrid approach combining WFEM with the commercial finite element software ANSYS is proposed to model complex metamaterial systems. Two examples illustrating its efficiency and accuracy to model an elastic metamaterial rod unit-cell using 1D simple rod element and 3D solid element are demonstrated and the results present good approximation to the experimental data.
•Elastic metamaterial Rod band gap calculation using wave finite element (WFEM).•Simulated examples with band gaps generated by Bragg scattering and local resonator.•Approach combining WFEM and ANSYS is proposed to model complex metamaterials.•Numerical results are compared with the experimental from a real metamaterial rod.
We investigate the complex band structure and forced response of flexural waves propagating in an elastic metamaterial thick plate. Mindlin-Reissner thick plate theory is considered. We study the ...influence of periodic arrays of spring-mass resonators attached to the surface of a homogeneous thick plate on the formation of Bragg-type and locally resonant band gaps. The plane wave expansion and extended plane wave expansion approaches are used to compute the complex band structure and wave shapes of the metamaterial thick plate with attached spring-mass resonators. An experimental analysis is conducted with a 3D-printed metamaterial plate with resonators. Modal shapes, forced response and band structure are computed by finite element and wave finite element methods. Analytical, numerical and experimental results present good agreement.
We investigate theoretically the band structure of flexural waves propagating in an elastic metamaterial thin plate. Kirchhoff-Love thin plate theory is considered. We study the influence of periodic ...arrays of multiple degrees of freedom local resonators in square and triangular lattices. Plane wave expansion and extended plane wave expansion methods, also known as ω(k) and k(ω), respectively, are used to solve the governing equation of motion for a thin plate. The locally resonant band gaps for square and triangular lattices present almost the same attenuation for all examples analysed. However, square lattice presents broader Bragg-type band gaps with higher attenuation than triangular lattice. An experimental analysis is conducted with a real elastic metamaterial thin plate with resonators in a square lattice. Modal analysis and forced response are computed by finite element method. Plane wave expansion, finite element and experimental results present good agreement.
An electrolyte supported solid oxide fuel cell (SOFC) using standard electrodes, doped-lanthanum manganite cathode and Ni-cermet anode, was operated with direct (anhydrous) ethanol for more than ...100h, delivering essentially the same power output as running on hydrogen. A ceria-based layer provides the catalytic activity for the gradual internal reforming, which uses the steam formed by the electrochemical oxidation of hydrogen for the decomposition of ethanol. Such a concept opens up the way for multi-fuel SOFCs using standard components and a catalytic layer.
► A solid oxide fuel cell was operated under anhydrous ethanol for more than 100h. ► The same power output was observed for both fuels, hydrogen and ethanol. ► A ceria-based layer provided the catalytic activity for ethanol decomposition. ► Anhydrous ethanol was decomposed by the gradual internal reforming. ► Such a concept opens up the way for multi-fuel SOFCs.
This study evaluates the effects of resin infiltrant composition and caries histological zone on the hydrolytic degradation of resininfiltrated artificial bovine enamel caries (RI-AEC). Different ...resin infiltrants were tested (n=26 per group): Icon (G1); TEGDMA 60%, UDMA 20%, and HEMA 20% (TUH); TEGDMA 80% and HEMA 20% (TH); and TEGDMA 75% and Bis-EMA 25% (TB). Following caries infiltration, samples were cut perpendicularly, and transverse microhardness were analyzed (at two histological zones: surface layer and lesion body) before and after 21 days of water immersion. TB presented lower decrease in microhardness (due to hydrolytic degradation) than the other groups, with a large effect size (Hedge’s G from 0.83 to 1.19) and high power (84 to 99%). Neither histological zone nor its interaction with resin infiltrant composition significantly affected the outcome. In conclusion, resin composition affected microhardness of RI-AEC upon water immersion, and TB was the least affected.
The anticonvulsant effect of α,β-epoxy-carvone (EC), a monoterpene monocyclic, was investigated in three animal models. EC at 300 or 400
mg/kg promoted protection of 75% and 87.5%, respectively, ...against convulsions induced chemically by pentylenetetrazole (PTZ) and it was efficient in prevents the tonic convulsions induced by maximal electroshock (MES) in doses of 200, 300 or 400
mg/kg, resulting in 25%, 25% and 100% of protection, respectively. This monoterpene was also capable to promote an increase of latency for development of convulsions induced by picrotoxin (PIC) at 300 or 400
mg/kg and presented a significant protection against convulsions at doses of 200, 300 or 400
mg/kg, resulting in 12.5%, 12.5% and 100% of protection, respectively. On the other hand, the anticonvulsant effect of EC, was not affected by pretreatment with flumazenil (FLU), a selective antagonist of benzodiazepine site of GABA
A receptor. Additionally was observed that EC treatment reduced the levels of in vitro lipoperoxidation and decreased (21.2%) the amplitude of compound action potential after 30
min of incubation. The present results clearly indicate the ability of EC to modulate the anticonvulsant and antioxidant effects. However, our data suggests that the action mechanisms are not due a direct activation of the GABA
A benzodiazepine receptors, but could be associated with the reduction of isolated nerve excitability, possibly involving a voltage-gated Na
+ channels blockade.
O presente artigo teve como objetivo relatar o processo de trabalho do apoiador matricial para o cuidado em saúde mental na atenção básica, na perspectiva da superação do modelo psiquiátrico ...tradicional. Trata-se de um relato de experiência realizada no Apoio Matricial – Núcleo de Apoio à Saúde da Família (NASF) do Distrito Sanitário II do município de João Pessoa-PB. Os dados foram coletados a partir de registros realizados no diário de campo do apoiador matricial. Entre as ações que foram realizadas pelo apoiador estão a cartografia, as reuniões de matriciamento em saúde mental, as discussões de casos, a visita domiciliar, o atendimento compartilhado, a articulação da rede, dentre outras. A experiência evidenciou que as atividades de matriciamento potencializaram a atuação das equipes da Atenção Básica para as demandas de saúde mental no território. Tais atividades apresentaram-se essenciais no processo de trabalho para a efetivação do cuidado em saúde mental. Além disso, possibilitou a corresponsabilização pelos usuários e suas famílias para maior resolutividade dos casos existentes no território.
Palavras – Chave: Apoio matricial; Sistema Único de Saúde; saúde mental.
Night-foraging cyclocephaline scarab beetles rely on floral structures of specific plant hosts for food and shelter, as well as mating sites. Although the role of floral fragrances as long-range ...attractants in these interactions has been elucidated, the mechanisms that mediate close-range mate discrimination in aggregations are still unclear. We recorded the mating-oriented behavior of male Cyclocephala distincta, focusing on the influence of contact signaling and movement over mate selection in a series of controlled bioassays. Roughly half of the males chose a conspecific female over another male, readily engaging in copulation upon initial contact. The remainder males required more experience, acquired through successive mounts on both females and males. Eventually, all focal males invested in copulation with females. When faced with the choice for a live or an inert conspecific female, male C. distincta preferred the former in 76% of cases, although we also recorded sexual investment on inert females (10% of cases). In paired experiments with an inert female or a male, nonetheless, focal males significantly opted for the opposite sex, and that included mating with the inert females. Innate characteristics of the females of C. distincta are evaluated by males synergistically, and not separately, in discriminating potential sexual partners.
Linalool oxide is a monoterpene that is found in some species of aromatic plants. The effects of the inhalation of linalool oxide (0.65%, 1.25%, 2.5% and 5.0% w/w) in the elevated plus-maze and ...light/dark box tests as animal models of anxiety were investigated in adult male mice and compared with the effects of the reference anxiolytic diazepam (0.5 and 2.0mg/kg), administered intraperitoneally. Additionally, the effects of inhaled linalool oxide were investigated in the rotarod test. Linalool oxide significantly increased the number of visits to the open arms of the elevated plus-maze and the amount of time spent there as well as the total number of entries. In the light/dark box test, inhalation of linalool oxide led to an increase in the time spent by the mice in the brightly-lit chamber and in the number of times the animal crossed from one compartment to another. Performance on the rotarod was unaffected. Thus, inhaled linalool oxide was found to have anxiolytic properties in both animal models, without causing any motor deficit. These results suggest that inhalation of linalool oxide may be a useful means of counteracting anxiety.
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►Inhaled linalool oxide presents anxiolytic properties in mice. ►Linalool oxide increases open entries and open duration in elevated plus-maze. ►Linalool oxide augments time spent in the light chamber in light/dark test. ►The performance of animals on rotarod is not altered.
Machado–Joseph disease or spinocerebellar ataxia type 3 (MJD/SCA3) is a fatal, autosomal dominant disorder caused by a cytosine-adenine-guanine expansion in the coding region of the MJD1 gene. RNA ...interference has potential as a therapeutic approach but raises the issue of the role of wild-type ataxin-3 (WT ATX3) in MJD and of whether the expression of the wild-type protein must be maintained. To address this issue, we both overexpressed and silenced WT ATX3 in a rat model of MJD. We showed that (i) overexpression of WT ATX3 did not protect against MJD pathology, (ii) knockdown of WT ATX3 did not aggravate MJD pathology and that (iii) non-allele-specific silencing of ataxin-3 strongly reduced neuropathology in a rat model of MJD. Our findings indicate that therapeutic strategies involving non-allele-specific silencing to treat MJD patients may be safe and effective.
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