Comment on "electromagnetic resonances in individual and coupled split-ring resonators"

Resonances appearing in split-ring resonators (SRR) were explained by the theory about the magnetoelectric coupling in the tensor polarizability of these particles. The relative strength of the resonances was explained from the numerical values of the different polarizabilities computed with the model. No resonant absorption was observed for incident waves with the perpendicular polarization

Efficient analysis of magnetostatic surface waves in printed and suspended ferrite loaded strip lines

This paper analyzes the guidance of magnetostatic surface waves (MSSW) by a metallic strip printed on a ferrimagnetic slab or on a dielectric/ferrimagnetic structure (suspended configuration) in the frame of the magnetostatic approach. An integral spectral domain analysis (SDA) is used for this purpose. Shielding upper and/or lower ground planes are also considered. Some interesting new physical effects, such as backward and complex MSSWs in the suspended configuration are reported. Good agreement with previously published experimental and computed results confirms the validity of our approach

Role of bianisotropy in negative, permeability and left-handed metamaterials

The recently proposed artificial media with negative magnetic permeability and left-handed metamaterials are revisited at the light of the theory of artificial bi(iso/aniso)tropic-media. In particular, the existence of bianisotropic effects in those materials is investigated, making use of an approximate model. Some unexplained properties of the electromagnetic-wave propagation through these media, revealed by closer inspection of previous numerical simulations and experimental work, are highlighted. It is shown that these peculiarities are properly explained if the bianisotropy is explicitly accounted for. The bianisotropy is related to the existence of magnetoelectric coupling in the artificial constituents (artificial atoms) of the medium. A simple modification of the artificial atom that precludes the bianisotropy is also proposed.Comisión Interministerial de Ciencia y Tecnología TIC2001-316

Comprehensive analysis of strip- and slot-line guided forward, backward, and complex magnetostatic waves

This paper presents a comprehensive and accurate analysis of the guidance of volume and surface magnetostatic waves by strips or slots in the presence of a ferrite slab magnetized to saturation by an external uniform magnetic field. The strip/slot can be directly printed on the ferrite surface or separated from it by means of a dielectric layer of arbitrary thickness. The problem is posed in terms of a suitable integral equation accounting for the magnetostatic limit. This equation is solved by using a spectral-domain formulation. The proposed method allows for the consideration of arbitrary magnetization angles and the presence of upper and/or lower ground planes. Strip-guided forward, backward, and complex surface magnetostatic waves have been obtained and analyzed in terms of the appropriate waveguide parameters. Slot-guided backward volume magnetostatic waves have been also computed and studied. Theoretical results have been checked against theoretical (magnetostatic and full wave) and experimental data available in the literature with reasonable agreement

Analysis of the propagation of leaky magnetostatic modes in normally magnetized microstrip and slot lines

The propagation of leaky forward magnetostatic (MS) volume waves along ferrite-loaded microstrip and slot lines is analyzed. This phenomenon is studied by means of a numerical approach based on the residue calculus technique because of its good numerical convergence and stability. The proposed method allows for a quick and accurate computation of the phase and attenuation constants of the leaky MS modes. A comparative analysis between both microstrip lines and slot lines is carried out, and some new physical effects, such as MS resonances in the radiation loss, are reported. The advantages of the proposed method of analysis over other numerical methods, such as Galerkin's or moment methods, are also discussed

Binding of [125I]Iodocyanopindolol by Rat Harderian Gland Crude Membranes: Kinetic Characteristics and Day-Night Variations

The Harderian glands are innervated by sympathetic fibers originating in the superior cervical ganglia. The aim of this study is to characterize the /3-adrenergic receptors in the rat Harderian gland. The characteristics of/3-adrenergic receptors were determined in crude membrane preparations from rat 125 125 Harderian gland, using [ I]iodocyanopindolol ([ I]CYP) as radioligand. The binding of the ligand to the receptor is rapid, reversible, saturable, specific and dependent on time, temperature and membrane concentration. At 30~ stoichiometric data suggest the presence of one binding site with a K a value of 0.29 nM and Bmax of 32 pmol/L. The interaction shows a high degree of specificity for /3-adrenergic agonists and blockers, as suggested by competitive displacement experiments with isoproterenol (ICso = 19.1 nM), propranolol (ICso = 28.1 nM), and norepinephrine (ICso = 96.3 nM). Clonidine, yohimbine, methoxamine, and prazosin are ineffective at concentrations up to 1 IzM. In the other hand, binding of [125I]CYP by Harderian gland membranes exhibits day-night variations. Binding values are low during the daytime and increase progressively late in the evening to reach a maximum at 2200 h (2 h after the onset of dark period), but decreased to the end of the dark period (0600 h). In conclusion, the results presented in this paper show the functional and pharmacological characterization of/3-adrenergic receptors in the rat Harderian gland. This neurotransmitter may play a physiological role at this level regulating, at least, processes such as a thyroid hormone metabolismComision Interministerial de Ciencia y Tecnología (España) PB94-1434Fondo de Investigaciones Sanitarias 93/021

Biocompatible and Thermoresistant Hydrogels Based on Collagen and Chitosan

Hydrogels are considered good biomaterials for soft tissue regeneration. In this sense, collagen is the most used raw material to develop hydrogels, due to its high biocompatibility. However, its low mechanical resistance, thermal stability and pH instability have generated the need to look for alternatives to its use. In this sense, the combination of collagen with another raw material (i.e., polysaccharides) can improve the final properties of hydrogels. For this reason, the main objective of this work was the development of hydrogels based on collagen and chitosan. The mechanical, thermal and microstructural properties of the hydrogels formed with different ratios of collagen/chitosan (100/0, 75/25, 50/50, 25/75 and 0/100) were evaluated after being processed by two variants of a protocol consisting in two stages: a pH change towards pH 7 and a temperature drop towards 4 °C. The main results showed that depending on the protocol, the physicochemical and microstructural properties of the hybrid hydrogels were similar to the unitary system depending on the stage carried out in first place, obtaining FTIR peaks with similar intensity or a more porous structure when chitosan was first gelled, instead of collagen. As a conclusion, the synergy between collagen and chitosan improved the properties of the hydrogels, showing good thermomechanical properties and cell viability to be used as potential biomaterials for Tissue Engineering.Ministerio de Ciencia e Innovación RTI2018-097100-B-C2

Deciphering the quality of SARS-CoV-2 specific T-cell response associated with disease severity, immune memory and heterologous response

SARS-CoV-2 specific T-cell response has been associated with disease severity, immune memory and heterologous response to endemic coronaviruses. However, an integrative approach combining a comprehensive analysis of the quality of SARS-CoV-2 specific T-cell response with antibody levels in these three scenarios is needed. In the present study, we found that, in acute infection, while mild disease was associated with high T-cell polyfunctionality biased to IL-2 production and inversely correlated with anti-S IgG levels, combinations only including IFN-γ with the absence of perforin production predominated in severe disease. Seven months after infection, both non-hospitalised and previously hospitalised patients presented robust anti-S IgG levels and SARS-CoV-2 specific T-cell response. In addition, only previously hospitalised patients showed a T-cell exhaustion profile. Finally, combinations including IL-2 in response to S protein of endemic coronaviruses were the ones associated with SARS-CoV-2 S-specific T-cell response in pre-COVID-19 healthy donors’ samples. These results could have implications for protective immunity against SARS-CoV-2 and recurrent COVID-19 and may help for the design of new prototypes and boosting vaccine strategies

Chemically specifi C multiscale modeling of clay-polymer nanocomposites reveals intercalation dynamics, tactoid self-assembly and emergent materials properties

A quantitative description is presented of the dynamical process of polymer intercalation into clay tactoids and the ensuing aggregation of polymerentangled tactoids into larger structures, obtaining various characteristics of these nanocomposites, including clay-layer spacings, out-of-plane clay-sheet bending energies, X-ray diffractograms, and materials properties. This model of clay-polymer interactions is based on a three-level approach, which uses quantum mechanical and atomistic descriptions to derive a coarse-grained yet chemically specifi c representation that can resolve processes on hitherto inaccessible length and time scales. The approach is applied to study collections of clay mineral tactoids interacting with two synthetic polymers, poly(ethylene glycol) and poly(vinyl alcohol). The controlled behavior of layered materials in a polymer matrix is centrally important for many engineering and manufacturing applications. This approach opens up a route to computing the properties of complex soft materials based on knowledge of their chemical composition, molecular structure, and processing conditions.This work was funded in part by the EU FP7 MAPPER project (grant number RI-261507) and the Qatar National Research Fund (grant number 09–260–1–048). Supercomputing time was provided by PRACE on JUGENE (project PRA044), the Hartree Centre (Daresbury Laboratory) on BlueJoule and BlueWonder via the CGCLAY project, and on HECToR and ARCHER, the UK national supercomputing facility at the University of Edinburgh, via EPSRC through grants EP/F00521/1, EP/E045111/1, EP/I017763/1 and the UK Consortium on Mesoscopic Engineering Sciences (EP/L00030X/1). The authors are grateful to Professor Julian Evans for stimulating discussions during the course of this project. Data-storage and management services were provided by EUDAT (grant number 283304)

IFNL4 ss469415590 polymorphism is associated with unfavourable clinical and immunological status in HIV-infected individuals

AbstractThe IFNL4 ss469415590 polymorphism, in high linkage disequilibrium with the IL28B rs12979860 variant, has been associated with hepatitis C virus clearance. We evaluated whether ss469415590 is associated with clinical and immunovirological parameters in human immunodeficiency virus-infected subjects. We found an independent association of the IFNL4 ss469415590 polymorphism with higher prevalence of AIDS-defining illnesses and lower CD4 T cell numbers. These results suggest the existence of common host defence mechanisms against different viral infections