Nasal Model Experiments Show That a Collimated Fluid Delivers Precise Doses to the Human Olfactory Cavity in the Side-Laying Position.

The nasal administration of therapeutic fluids and vaccines is used to treat allergic rhinitis, sinusitis, congestion, coronaviruses and even Alzheimer's disease. In the latter, the drug must reach the olfactory region, so it finds its way into the central nervous system. Effective administration techniques able to reach the olfactory region are challenging due to the tortuous anatomy of the nasal cavity, and are frequently evaluated in vitro using transparent anatomical models. Here, the liquid distribution inside a 3D printed human nasal cavity is quantified for model fluids resulting from the discharge of a 1-mL syringe with either a spray-generating nozzle, and a straight tip emitting a collimated fluid stream. Experiments using two model fluids with different viscosities suggest that a simple, correctly positioned straight tip attached to a syringe is able to efficiently deliver most of a therapeutic fluid in the human olfactory region in the side-laying position, avoiding the adoption of head-back and head-down positions that can be difficult for patients in the age range typical of Alzheimer's disease. Furthermore, we demonstrate by computer simulations that the conclusion is valid within a wide range of parameters.

Observation of Linear and Nonlinear Light Localization at the Edges of Moiré Arrays.

We observe linear and nonlinear light localization at the edges and in the corners of truncated moiré arrays created by the superposition of periodic mutually twisted at Pythagorean angles square sublattices. Experimentally exciting corner linear modes in the femtosecond-laser written moiré arrays we find drastic differences in their localization properties in comparison with the bulk excitations. We also address the impact of nonlinearity on the corner and bulk modes and experimentally observe the crossover from linear quasilocalized states to the surface solitons emerging at the higher input powers. Our results constitute the first experimental demonstration of localization phenomena induced by truncation of periodic moiré structures in photonic systems.

Observation of Edge Solitons in Topological Trimer Arrays.

We report the experimental observation of nonlinear light localization and edge soliton formation at the edges of fs-laser written trimer waveguide arrays, where transition from nontopological to topological phases is controlled by the spacing between neighboring trimers. We found that, in the former regime, edge solitons occur only above a considerable power threshold, whereas in the latter one they bifurcate from linear states. Edge solitons are observed in a broad power range where their propagation constant falls into one of the topological gaps of the system, while partial delocalization is observed when considerable nonlinearity drives the propagation constant into an allowed band, causing coupling with bulk modes. Our results provide direct experimental evidence of the coexistence and selective excitation in the same or in different topological gaps of two types of topological edge solitons with different internal structures, which can rarely be observed even in nontopological systems. This also constitutes the first experimental evidence of formation of topological solitons in a nonlinear system with more than one topological gap.

Metabolic and neurological consequences of the treatment with polyphenols: a systematic review in rodent models of noncommunicable diseases.

BACKGROUND: Noncommunicable diseases (NCDs) lead to drastic metabolic alterations with associated energy balance and body weight changes, two related physiological processes regulated by the brain. Polyphenol-based treatments for NCDs have emerged as a promising therapy, which seems to involve the energy balance modulation. However, it remains unclear what the most effective polyphenols-based treatment is to attenuate adverse effects in the energy balance of NCDs. OBJECTIVES: This systematic review aimed to evaluate the literature on the metabolic and neurological effects of polyphenols-based treatment in rodent models of NCDs. METHODS: Literature search was carried out in the following databases: CINAHL, Medline/PubMed, SCOPUS, and Web of Science. For title and abstract screening, original papers with polyphenols exposure in rodents were selected. For full-text screening, studies with models of NCDs that reported metabolic and neurological outcomes when treated with polyphenols were selected for inclusion in this review. RESULTS: 23 articles, using individual compound (11 articles) or polyphenols extracts (12 articles), were included in this review: 5 articles using tea polyphenols, 12 articles using grape-derived polyphenols, 3 articles using the polyphenol quercetin, and 3 articles using other polyphenol sources. Most results agree on the beneficial effect of polyphenols in attenuating alterations in energy balance and body weight. Such effects were associated with neuroprotective responses in different brain areas including hippocampus and hypothalamus. CONCLUSION: In conclusion, this review shows that the treatment with polyphenols, especially resveratrol or quercetin, attenuates the adverse effects of NCDs on energy balance and are associated with neuroprotective effects.

Nonlinear higher-order polariton topological insulator.

We address the resonant response and bistability of the exciton-polariton corner states in a higher-order nonlinear topological insulator realized with a kagome arrangement of microcavity pillars. Such states are resonantly excited and exist due to the balance between pump and losses, on one hand, and between nonlinearity and dispersion in inhomogeneous potential landscape, on the other hand, for pump energy around eigen-energies of corresponding linear localized modes. Localization of the nonlinear corner states in a higher-order topological insulator can be efficiently controlled by tuning pump energy. We link the mechanism of corner state formation with symmetry of the truncated kagome array. Corner states coexist with densely packed edge states but are well isolated from them in energy. Nonlinear corner states persist even in the presence of perturbations in a corner microcavity pillar.

Anderson cross-localization.

We report Anderson localization in two-dimensional optical waveguide arrays with disorder in waveguide separation introduced along one axis of the array, in an uncorrelated fashion for each waveguide row. We show that the anisotropic nature of such disorder induces a strong localization along both array axes. The degree of localization in the cross-axis remains weaker than that in the direction in which disorder is introduced. This effect is illustrated both theoretically and experimentally.

Observation of the gradual transition from one-dimensional to two-dimensional Anderson localization.

We study the gradual transition from one-dimensional (1D) to two-dimensional (2D) Anderson localization upon transformation of the dimensionality of disordered waveguide arrays. An effective transition from a 1D to a 2D system is achieved by increasing the number of rows forming the arrays. We observe that, for a given disorder level, Anderson localization becomes weaker with increasing numbers of rows-hence the effective dimension.

Vortex twins and anti-twins supported by multiring gain landscapes.

We address the properties of multivortex soliton complexes supported by multiring gain landscapes in focusing Kerr nonlinear media with strong two-photon absorption. Stable complexes incorporating two, three, or four vortices featuring opposite or identical topological charges are shown to exist. In the simplest geometries with two amplifying rings vortex twins with equal topological charges exhibit asymmetric intensity distributions, while vortex anti-twins may be symmetric or asymmetric, depending on the gain level and separation between rings.

Wave localization at the boundary of disordered photonic lattices.

We report on the experimental observation of reduced light-energy transport and disorder-induced localization close to a boundary of a truncated 1D disordered photonic lattice. Our observations uncover that a higher level of disorder near the boundary is required to obtain similar localization than in the bulk.

Three-dimensional light bullets in arrays of waveguides.

We report the first experimental observation of three-dimensional light bullets, excited by femtosecond pulses in a system featuring quasi-instantaneous cubic nonlinearity and a periodic, transversally modulated refractive index. Stringent evidence of the excitation of light bullets is based on time-gated images and spectra which perfectly match our numerical simulations. Furthermore, we reveal a novel evolution mechanism forcing the light bullets to follow varying dispersion or diffraction conditions, until they leave their existence range and decay.

Observation of two-dimensional superlattice solitons.

We observe experimentally two-dimensional solitons in superlattices comprising alternating deep and shallow waveguides fabricated via the femtosecond-laser direct writing technique. We find that the symmetry of linear diffraction patterns as well as soliton shapes and threshold powers largely differ for excitations centered on deep and shallow sites. Thus, bulk and surface solitons centered on deep waveguides require much lower powers than their counterparts on shallow sites.

Efectos del estiramiento isquiotibial sobre el patrón de activación muscular del recto del abdomen durante la flexoextensión del tronco / Effects of hamstring stretching on rectus abdominis muscle activation pattern during trunk flexion and extension

ObjetivoDeterminar los efectos del estiramiento de las estructuras isquiotibiales mediante técnicas de facilitación neuromuscular propioceptiva sobre el patrón de activación del recto del abdomen durante los movimientos de flexoextensión del tronco.HipótesisEl estiramiento repetido de las estructuras isquiotibiales podría retrasar la activación del recto del abdomen durante la flexión del tronco y adelantarla durante la extensión.MetodologíaSe registraron en 11 sujetos voluntarios la activación electromiográfica del recto del abdomen y los grados de flexión de la cadera durante movimientos de flexoextensión del tronco antes y después de realizar los estiramientos. Las variables de estudio fueron los porcentajes de flexión de la cadera al inicio y al final de la contracción del recto del abdomen y la actividad electromiográfica media del músculo.ResultadosEl t-test mostró que hay diferencias significativas en el inicio y el final de la contracción del recto del abdomen (onset y offset) antes y después del estiramiento (p<0,05).ConclusiónTras un estiramiento prolongado de la musculatura isquiotibial, el recto del abdomen tarda más tiempo en activarse durante la flexión del tronco, y la contracción es de menor duración. El efecto combinado de la laxitud aumentada de las estructuras isquiotibiales y la alteración de la respuesta del recto del abdomen podría alterar los sistemas sensoriomotores de control del movimiento de la región lumbopélvica, aumentando el riesgo de lesiones(AU)

ObjectiveTo determine the effects of hamstring stretching (propioceptive neuromuscular propioception) on the muscle activation pattern of rectus abdominis (RA) during trunk flexion and extension.HypothesisRepeated hamstring stretching techniques could either delay or anticipate RA activation during trunk flexion or extension, respectively.MethodologyElectromyography activity of the rectus abdominis and grades of hip flexion during flexion-extension movements of the trunk before and after stretching hamstring muscles was recorded in 11 volunteer subjects. Study variables: RA onset, RA offset (expressed as a percentage of the maximum hip flexion value) and RA average EMG.ResultsThe paired T-test showed significant differences in RA onset and offset before and after stretching (p<0.05).ConclusionAfter prolonged hamstring muscle stretching, the rectus abdominis takes a long time to become activated during trunk flexion and the contraction is shorter. The combined effect of increased laxity of hamstring and altered response of RA after stretching might alter the sensorimotor systems of lumbopelvic region motor control, increasing the risk of injuries(AU)

Light tunneling inhibition and anisotropic diffraction engineering in two-dimensional waveguide arrays.

We address two-dimensional (2D) waveguide arrays where light tunneling into neighboring waveguides may be effectively suppressed by an out-of-phase harmonic modulation of the refractive index in neighboring waveguides at suitable frequencies. Genuine 2D features, such as anisotropic diffraction engineering, diffraction-free propagation along selected directions in the transverse plane, and tunneling inhibition for multichannel vortices, are shown to occur.

Nonlinearity-induced broadening of resonances in dynamically modulated couplers.

We report the observation of nonlinearity-induced broadening of resonances in dynamically modulated directional couplers. When the refractive index of the guiding channels in the coupler is harmonically modulated along the propagation direction and is out-of-phase in two channels, coupling can be completely inhibited at resonant modulation frequencies. We observe that nonlinearity broadens such resonances and that localization can be achieved even in detuned systems at power levels well below those required in unmodulated couplers.

Observation of two-dimensional coherent surface vector lattice solitons.

We report, to the best of our knowledge, the first experimental observation of vector surface solitons, which form at the edge and in the corner of two-dimensional laser-written waveguide arrays. These elliptically polarized vector states are composed of two orthogonally polarized components. They exist only above a power threshold and bifurcate from scalar surface solitons. The components of a vector soliton may have substantially different degrees of localization in certain parameter ranges.

Inhibition of light tunneling in waveguide arrays.

We report the observation of almost perfect light tunneling inhibition at the edge and inside laser-written waveguide arrays due to band collapse. When the refractive index of the guiding channels is harmonically modulated along the propagation direction and out-of-phase in adjacent guides, light is trapped in the excited waveguide over a long distance due to resonances. The phenomenon can be used for tuning the localization threshold power.

Observation of two-dimensional defect surface solitons.

We report on the experimental observation of two-dimensional solitons located in defect channels at the surface of a hexagonal waveguide array. The threshold power for the excitation of solitons existing owing to total internal reflection grows with decrease of the refractive index in negative defects and vanishes for sufficiently strong positive defects. Negative defects can also support linear surface modes existing owing to Bragg-type reflections.

Soliton excitation in waveguide arrays with an effective intermediate dimensionality.

We reveal and observe experimentally significant modifications undertaken by discrete solitons in waveguide lattices upon the continuous transformation of the lattice structure from one-dimensional to two-dimensional. Light evolution and soliton excitation in arrays with a gradually increasing number of rows are investigated, yielding solitons with an effective reduced dimensionality residing at the edge and in the bulk of the lattice.

Angular surface solitons in sectorial hexagonal arrays.

We report on the experimental observation of corner surface solitons localized at the edges joining planar interfaces of hexagonal waveguide array with uniform nonlinear medium. The face angle between these interfaces has a strong impact on the threshold of soliton excitation as well as on the light energy drift and diffraction spreading.