Phycobiliprotein from Arthrospira maxima: Conversion to nanoparticles by high-energy ball milling, structural characterization, and evaluation of their anti-inflammatory effect.

Arthrospira maxima is a source of phycobiliproteins with different nutraceutical properties, e.g. antioxidant and anti-inflammatory activities. The current study was aimed at the elaboration, characterization, and evaluation of the anti-inflammatory effect of the phycobiliprotein nanoparticles extracted from Arthrospira maxima. Previously freeze-dried phycobiliproteins were milled by high-energy ball milling until reaching a nanometric size (optimal time: 4 h). Microscopy techniques were used for the characterization of the size and morphology of phycobiliproteins nanoparticles. Additionally, a spectroscopic study evidenced that nanosized reduction induced an increase in the chemical functional groups associated with its anti-inflammatory activity that was tested in a murine model, showing an immediate inflammatory effect. The novelty and importance of this contribution was to demonstrate that high energy ball milling is an emerging and green technology that can produce phycobiliprotein nanoparticles on a large-scale, without the use of organic solvents, to test their nutraceutical properties in a biological model by intragastric administration.

Shadows of structured beams in lenslike media.

The self-healing phenomenon of structured light beams has been comprehensively investigated for its important role in various applications including optical tweezing, superresolution imaging, and optical communication. However, for different structured beams, there are different explanations for the self-healing effect, and a unified theory has not yet been formed. Here we report both theoretically and experimentally a study of the self-healing effect of structured beams in lenslike media, this is, inhomogeneous lenslike media with a quadratic gradient index. By observing the appearance of a number of shadows of obstructed structured wave fields it has been demonstrated that their self-healing in inhomogeneous media are the result of superposition of fundamental traveling waves. We have found that self-healing of structured beams occurs in this medium and, interestingly enough, that the shadows created in the process present sinusoidal propagating characteristics as determined by the geometrical ray theory in lenslike media. This work provides what we believe to be a new inhomogenous environment to explain the self-healing effect and is expected to deepen understanding of the physical mechanism.

Symmetric gradient-index media reconstruction.

Ray tracing in gradient-index (GRIN) media has been thoroughly studied and several ray tracing methods have been proposed. Methods are based on finding the ray path given a known GRIN. In recent decades, the inverse problem, which consists of finding the GRIN distribution for a given light ray path, has been gaining attention. Given that it is not an easy task, the methods proposed in the literature vary in degrees of difficulty. In this work, an alternative method is presented to derive symmetric GRIN distributions whose implementation can be considered the simplest to date. Since it is based on invariants, which result from the symmetries of the system as stated by Fermat's principle, it is an exact numerical method, i.e., the physical system is not approximated. The robustness of the method permits the reconstruction of the GRIN distribution from a ray propagating in three-dimensions. In order to demonstrate its operation, different known symmetric GRIN media are reconstructed using rays that propagate in two and three dimensions.

Brain site-specific regulation of hedonic intake by orexin and DYN peptides: role of the PVN and obesity.

The orexin peptides promote hedonic intake and other reward behaviors through different brain sites. The opioid dynorphin peptides are co-released with orexin peptides but block their effects on reward in the ventral tegmental area (VTA). We previously showed that in the paraventricular hypothalamic nucleus (PVN), dynorphin and not orexin peptides enhance hedonic intake, suggesting they have brain-site-specific effects. Obesity alters the expression of orexin and dynorphin receptors, but whether their expression across different brain sites is important to hedonic intake is unclear. We hypothesized that hedonic intake is regulated by orexin and dynorphin peptides in PVN and that hedonic intake in obesity correlates with expression of their receptors. Here we show that in mice, injection of DYN-A1-13 (an opioid dynorphin peptide) in the PVN enhanced hedonic intake, whereas in the VTA, injection of OXA (orexin-A, an orexin peptide) enhanced hedonic intake. In PVN, OXA blunted the increase in hedonic intake caused by DYN-A1-13. In PVN, injection of norBNI (opioid receptor antagonist) reduced hedonic intake but a subsequent OXA injection failed to increase hedonic intake, suggesting that OXA activity in PVN is not influenced by endogenous opioid activity. In the PVN, DYN-A1-13 increased the intake of the less-preferred food in a two-food choice task. In obese mice fed a cafeteria diet, orexin 1 receptor mRNA across brain sites involved in hedonic intake correlated with fat preference but not caloric intake. Together, these data support that orexin and dynorphin peptides regulate hedonic intake in an opposing manner with brain-site-specific effects.

Generalization of ray tracing in symmetric gradient-index media by Fermat's ray invariants.

Ray tracing in gradient-index (GRIN) media has been traditionally performed either by using the analytical or numerical solutions to the Eikonal equation or by creating a layered medium where Snell's law is calculated in each layer. In this paper, an exact general method to perform ray tracing in GRIN media is presented based on the invariants of the system as stated by Fermat's principle when the media presents symmetries. Its advantage, compared with other methods reported in the literature, relies on its easy implementation. Besides the GRIN distribution and the initial conditions of the incident ray, once the invariants of the system are stated the resulting math is simple to solve and interpret. To benchmark the algorithm, ray tracing in typical cases of GRIN media is calculated, finding minimal discrepancies between the analytical solutions and our simulations. The used media are axial refractive index and parabolic index fiber and lenses with spherical gradient-index symmetry, such as: Luneburg's, Gutman's, generalized Maxwell's Fish-eye, Eaton's, and concentrator lenses. Our method can be further applied to distributions with symmetries associated with other common curvilinear orthogonal coordinate systems, in particular to those associated to the separability of the Helmholtz equation that would allow us to investigate wave optics in these GRIN media with the associated geometries.

What are the traveling waves composing the Hermite-Gauss beams that make them structured wavefields?

To the best of our knowledge, at the present time there is no answer to the fundamental question stated in the title that provides a complete and satisfactory physical description of the structured nature of Hermite-Gauss beams. The purpose of this manuscript is to provide proper answers supported by a rigorous mathematical-physics framework that is physically consistent with the observed propagation of these beams under different circumstances. In the process we identify that the paraxial approximation introduces spurious effects in the solutions that are unphysical. By removing them and using the property of self-healing, that is characteristic to structured beams, we demonstrate that Hermite-Gaussian beams are constituted by the superposition of four traveling waves.

Severe bowel complications in SARS-CoV-2 patients receiving protocolized care.

INTRODUCTION AND AIMS: A case series of ten patients that received protocolized care for SARS-CoV-2 infection and developed severe gastrointestinal complications, is presented. The aim of our study was to contribute to the ongoing discussion regarding gastrointestinal complications related to SARS-CoV-2 infection. After reviewing the current literature, ours appears to be the first detailed case series on the topic. MATERIALS AND METHODS: A retrospective filtered search of all patients admitted to our hospital for SARS-CoV-2 infection, who developed severe gastrointestinal complications, was performed. All relevant data on hospital patient management, before and after surgery, were collected from the medical records. RESULTS: Of the 905 patients admitted to our hospital due to SARS-CoV-2 infection, as of August 26, 2020, ten of them developed severe gastrointestinal complications. Seven of those patients were men. There were four cases of perforation of the proximal jejunum, three cases of perforations of the ascending colon, one case of concomitant perforation of the sigmoid colon and terminal ileum, one case of massive intestinal necrosis, and one preoperative death. Three right colectomies, four intestinal resections, one Hartmann's procedure with bowel resection, and one primary repair of the small bowel were performed. The mortality rate of the patients analyzed was 50%. CONCLUSION: Spontaneous bowel perforations and acute mesenteric ischemia are emerging as severe, life-threatening complications in hospitalized SARS-CoV-2 patients. More evidence is needed to identify risk factors, establish preventive measures, and analyze possible adverse effects of the current treatment protocols.

[Severe bowel complications in SARS-CoV-2 patients receiving protocolized care]. / Complicaciones intestinales graves en pacientes SARS-CoV-2 recibiendo manejo protocolizado.

Introduction and aims: A case series of ten patients that received protocolized care for SARS-CoV-2 infection and developed severe gastrointestinal complications, is presented. The aim of our study was to contribute to the ongoing discussion regarding gastrointestinal complications related to SARS-CoV-2 infection. After reviewing the current literature, ours appears to be the first detailed case series on the topic. Materials and methods: A retrospective filtered search of all patients admitted to our hospital for SARS-CoV-2 infection, who developed severe gastrointestinal complications, was performed. All relevant data on hospital patient management, before and after surgery, were collected from the medical records. Results: Of the 905 patients admitted to our hospital due to SARS-CoV-2 infection, as of August 26, 2020, ten of them developed severe gastrointestinal complications. Seven of those patients were men. There were four cases of perforation of the proximal jejunum, three cases of perforations of the ascending colon, one case of concomitant perforation of the sigmoid colon and terminal ileum, one case of massive intestinal necrosis, and one preoperative death. Three right colectomies, four intestinal resections, one Hartmann's procedure with bowel resection, and one primary repair of the small bowel were performed. The mortality rate of the patients analyzed was 50%. Conclusion: Spontaneous bowel perforations and acute mesenteric ischemia are emerging as severe, life-threatening complications in hospitalized SARS-CoV-2 patients. More evidence is needed to identify risk factors, establish preventive measures, and analyze possible adverse effects of the current treatment protocols.

Kepler's law for optical beams.

It is well known that optics and classical mechanics are intimately related. One of the most important concepts in classical mechanics is that of a particle in a central potential that leads to the Newtonian description of the planetary dynamics. Within this, a relevant result is Kepler's second law that is related to the conservation of orbital angular momentum, one of the fundamental laws in physics. In this paper, we demonstrate that it is possible to find the conditions that allow us to state Kepler's second law for optical beams with orbital angular momentum by analyzing the streamlines of their energy flow. We find that the optical Kepler's law is satisfied only for cylindrical symmetric beams in contrast to the classical mechanics situation that is satisfied for the other conic geometries, namely, parabolic, elliptical and hyperbolic. We propose a novel approach to confirm our analytic results: we observe the propagation of the Arago's spot created by a beam with orbital angular momentum as a local "light-tracer" instead of looking at the propagation of the whole beam. The observed patterns fully agree with the prediction of our formalism.

Single function crystalline lens capable of mimicking ciliary body accommodation.

The lens is a complex optical component of the human eye because of its physiological structure: the surface is aspherical and the structural entities create a gradient refractive index (GRIN). Most existent models of the lens deal with its external shape independently of the refractive index and, subsequently, through optimization processes, adjust the imaging properties. In this paper, we propose a physiologically realistic GRIN model of the lens based on a single function for the whole lens that accurately describes different accommodative states simultaneously providing the corresponding refractive index distribution and the external shape of the lens by changing a single parameter that we associate with the function of the ciliary body. This simple, but highly accurate model, is incorporated into a schematic eye constructed with reported experimental biometric data and accommodation is simulated over a range of 0 to 6 diopters to select the optimum levels of image quality. Changes with accommodation in equatorial and total axial lens thicknesses, as well as aberrations, are found to lie within reported biometric data ranges.

Probing the reciprocal lattice associated with a triangular slit to determine the orbital angular momentum for a photon.

The orbital angular momentum conservation of light reveals different diffraction patterns univocally dependent on the topological charge of the incident light beam when passing through a triangular aperture. It is demonstrated that these patterns, which are accessed by observing the far-field measurement of the diffracted light, can also be obtained using few photon sources. In order to explain the observed patterns, we introduce an analogy of this optical phenomenon with the study of diffraction for the characterization of the crystal structure of solids. We demonstrate that the finite pattern can be associated with the reciprocal lattice obtained from the direct lattice generated by the primitive vectors composing any two of the sides of the equilateral triangular slit responsible for the diffraction. Using the relation that exists between the direct and reciprocal lattices, we provide a conclusive explanation as to why the diffraction pattern of the main maxima is finite. This can shed a new light on the investigation of crystallographic systems.

Intelligent-assistant system for scleral spur location.

A system based on the use of two artificial neural networks (ANNs) to determine the location of the scleral spur of the human eye in ocular images generated by an ultrasound biomicroscopy is presented in this paper. The two ANNs establish a relationship between the distance of four manually placed landmarks in an ocular image with the coordinates of the scleral spur. The latter coordinates are generated by the expert knowledge of a subject matter specialist. Trained ANNs that generate good results for scleral spur location are incorporated into a software system. Statistical indicators and results yield an efficiency performance above 95%.

Topographic synthesis of arbitrary surfaces with vortex Jinc functions.

When a circular aperture is uniformly illuminated, it is possible to observe in the far field an image of a bright circle surrounded by faint rings known as the Airy pattern or Airy disk. This pattern is described by the first-order Bessel function of the first type divided by its argument expressed in circular coordinates. We introduce the higher-order Bessel functions with a vortex azimuthal factor to propose a family of functions to generalize the function defining the Airy pattern. These functions, which we call vortex Jinc functions, happen to form an orthogonal set. We use this property to investigate their usefulness in fitting various surfaces in a circular domain, with applications in precision optical manufacturing, wavefront optics, and visual optics, among others. We compare them with other well-known sets of orthogonal functions, and our findings show that they are suitable for these tasks and can pose an advantage when dealing with surfaces that concentrate a considerable amount of their information near the center of a circular domain, making them suitable applications in visual optics or analysis of aberrations of optical systems, for instance, to analyze the point spread function.

Criterios y prácticas de externaciones de niños en contextos de encierro / Criteria and practices of externalization of children in confinement contexts

INTRODUCCIÓN La salida de los niños del ámbito carcelario conlleva una separación tanto de sus madres como de un conjunto de prácticas propias de la institución y la consecuente inserción en un contexto diferente. Si bien los procesos de extenuación están orientados fundamentalmente por el discurso jurídico, despliegan una estructura compleja en la que se ponen en juego múltiples variables que no han sido exploradas suficientemente desde el campo de la Salud Mental. OBJETIVOS Estudiar y analizar los criterios y las prácticas de extenuación de niños alojados junto a sus madres en la Unidad Penitenciaria Nº33, desde una perspectiva de Salud Mental Objetivos Estudiar y analizar los criterios y las prácticas de externación de niños alojados junto a sus madres en la Unidad Penitenciaria Nº33, desde una perspectiva de Salud Mental. MÉTODOS Se realizó un estudio exploratorio de corte cualitativo, con entrevistas semiestructuradas como principal técnica para la obtención de dato. RESULTADOS Se identificaron dos modalidades de egreso de niños del ámbito carcelario. Se elaboraron variables desde las cuales se dilucidaron factores intervinientes en el proceso de externación, que incluyen las prácticas y criterios del procedimiento, a saber a) modo de participación de las madres en la externación b) lugar del niño en el discurso materno e institucional c) intervenciones del Consejo Asistido d) participación de organismos extrapenitenciarios y e) edad del niño. DISCUSIÓN Los procedimientos de externación son llevados adelante por el personal penitenciario, que trabaja dentro del contexto carcelario atendiendo las necesidades de la población detenida y cuenta con escasa colaboración de sectores especializados en materia de niñez y adolescencia. Los procesos de externación tienen como principal actor a las mujeres madres, quienes presentan diversas respuestas a la problemática e inciden directamente en el resultado de tal proceso. Las variables construidas resultan relevantes para diseñar políticas públicas, especialmente en lo concerniente a la planificación de programas orientados a la atención del campo de la niñez.

[Reversible alterations in the neuroimages associated with vigabatrine treatment in infants with epileptic spasms]. / Alteraciones reversibles en la neuroimagen asociadas al tratamiento con vigabatrina en lactantes con espasmos epilepticos.

INTRODUCTION: Vigabatrin (VGB) is a first-line drug for the treatment of infantile spasms. Recently, several reports claim the existence of abnormalities in magnetic resonance imaging (MRI) (particularly affecting basal ganglia, and visible in T2 and diffusion sequences) in infants with spasms that were receiving high doses of VGB (> 100 mg/kg/day), which appear to be reversible after withdrawal of treatment. CASE REPORTS: We present two cases with an epileptic encephalopathy in the first year of life and seizures consisting of infantile spasms. Both were treated with several antiepileptic drugs, including VGB up to a maximum dosage of 200 mg/kg/day. At the age of 11 and 28 months, respectively, MRI images showed marked signal hyperintensities on T2-sequences on bilateral globus pallidus, thalamus, posterior portion of the brainstem and dentate nuclei, also visible on diffusion sequences. Both had previous unaltered MRI studies. After excluding an underlying metabolic disease, VGB withdrawal is decided, appreciating the reversibility of those lesions in a prospective MRI study, three months later. CONCLUSIONS: We must consider and carefully evaluate findings on brain MRI in infants receiving VGB at high doses for treatment of spasms. The apparent cytotoxic effect on basal ganglia could simulate metabolic/mitochondrial diseases. By knowing this effect of VGB and its typical MRI features, unnecessary testing can be avoided in young infants with epileptic encephalopathies, including complex procedures like muscle biopsy or a new metabolic screening.

TITLE: Alteraciones reversibles en la neuroimagen asociadas al tratamiento con vigabatrina en lactantes con espasmos epilepticos.Introduccion. La vigabatrina (VGB) es un farmaco de primera linea para el tratamiento de espasmos infantiles. Diversos estudios han hallado anomalias en la resonancia magnetica (RM) cerebral, que afectaban particularmente a los ganglios de la base, y especialmente en secuencias de difusion, en lactantes con espasmos que recibian VGB en altas dosis (> 100 mg/kg/dia), y se ha observado la desaparicion de las lesiones tras la retirada de dicho tratamiento. Casos clinicos. Se presentan dos casos clinicos con inicio de una encefalopatia epileptica en el primer año de vida y crisis en forma de espasmos infantiles. Ambos recibieron tratamiento con distintos farmacos, entre ellos VGB hasta dosis de 200 mg/kg/dia. Con 11 y 28 meses de vida, respectivamente, aparecian imagenes en la RM cerebral con una marcada hiperintensidad de señal en secuencias ponderadas en T2 en ambos palidos, talamos, porcion posterior del tronco encefalico y nucleos dentados, que asociaban restriccion en secuencias de difusion. Ambos disponian de estudios previos de RM, sin alteraciones. Tras excluir una metabolopatia subyacente, se decidio la retirada de la VGB y tres meses despues, en una RM de control, se aprecio la total reversibilidad de dichas lesiones. Conclusiones. Deben evaluarse con cautela los hallazgos de la RM cerebral en lactantes que reciban VGB en altas dosis para el tratamiento de espasmos. Su aparente efecto citotoxico sobre los ganglios de la base podria simular metabolopatias/enfermedades mitocondriales. Conocer este efecto de la VGB y sus caracteristicas tipicas en la RM puede evitar pruebas innecesarias, como una biopsia muscular o un nuevo cribado metabolico.

Three-dimensional ray tracing in spherical and elliptical generalized Luneburg lenses for application in the human eye lens.

Ray tracing in spherical Luneburg lenses has always been represented in 2D. All propagation planes in a 3D spherical Luneburg lens generate the same ray tracing, due to its radial symmetry. A geometry without radial symmetry generates a different ray tracing. For this reason, a new ray tracing method in 3D through spherical and elliptical Luneburg lenses using 2D methods is proposed. The physics of the propagation is shown here, which allows us to make a ray tracing associated with a vortex beam. A 3D ray tracing in a composite modified Luneburg lens that represents the human eye lens is also presented.

Composite modified Luneburg model of human eye lens.

A new lens model based on the gradient-index Luneburg lens and composed of two oblate half spheroids of different curvatures is presented. The spherically symmetric Luneburg lens is modified to create continuous isoindicial contours and to incorporate curvatures that are similar to those found in a human lens. The imaging capabilities of the model and the changes in the gradient index profile are tested for five object distances, for a fixed geometry and for a fixed image distance. The central refractive index decreases with decreasing object distance. This indicates that in order to focus at the same image distance as is required in the eye, a decrease in refractive power is needed for rays from closer objects that meet the lens surface at steeper angles compared to rays from more distant objects. This ensures a highly focused image with no spherical aberration.

[Complications of peripheral parenteral nutrition. Clinical observations of 2 cases]. / Complicaciones de la nutrición parenteral periférica. Observación clínica de 2 casos.

INTRODUCTION: Peripheral parenteral nutrition (PPN) is artificial nutrition used when digestive absorption is insufficient. It supplies the nutritional needs of the patient and permits administration through a peripheral catheter. WE PRESENT 2 CLINICAL CASES: The first one entails an epidermolisis through extravasation masked by temporo-spatial disorientation of the patient with appearance of flictenes (blisters). Prolonged treatment and consultation with plastic surgery were required. The second case entails a chemical phlebitis with early detection by nursing professionals. It was resolved with short term treatment and did not require consultation with the plastic surgeon. PLANNING CARE: We elaborated a care plan aimed at identifying real or potential problems related with possible complications of intravenous PPN administration, such as phlebitis and extravasation. The aim of this research was prevention, early detection and treatment. DISCUSSION: Phlebitis is related with catheter characteristics, in-dwelling time and high osmolarity of PPN. Early action decreases injury of the affected tissue. In case 1, the patient requires 19 days of curing. This was only 72 h in case 2. CONCLUSION: The nursing staff plays an essential role in catheter election, localization, administration and preventing complications. Staff training and a procedure protocol greatly reduce the incidence of phlebitis, avoid discomfort for the patient and reduce health care cost.

Splitting after collision of high-order bright spatial solitons in Kerr media.

By numerically studying the collision between (1 + 1)-Dimensional high order bright spatial solitons in a Kerr nonlinear media we show that after the collision, the high order solitons split into a number of first order solitons that corresponds to its order. Two different collision scenarios are considered: collision between two independent high order solitons and a collision with a virtual soliton simulated by the reflection at an angle of a high order soliton at a linear interface. The results demonstrate that in both cases the high order solitons split showing minor differences.

New asymmetric propagation invariant beams obtained by amplitude and phase modulation in frequency space.

In this paper, we demonstrate, numerically and experimentally that using the mask-lens setup used by Durnin to generate Bessel beams Durnin [Phys. Rev. Lett. 58, 1499 (1987)], it is possible to generate different kinds of propagation invariant beams. A modification in the amplitude or phase of the field that illuminates the annular slit is proposed that corresponds to modulation in frequency space. In particular, we characterize the new invariant beams that were obtained by modulating the amplitude of the annular mask and when the incident field was modulated with a one-dimensional quadratic or cubic phase. Experimental results using an amplitude mask are shown in order to corroborate the numerical predictions.