2,072 research outputs found
Anisotropic thermal magnetoresistance for an active control of radiative heat transfer
We predict a huge anisotropic thermal magnetoresistance (ATMR) in the
near-field radiative heat transfer between magneto-optical particles when the
direction of an external magnetic field is changed with respect to the heat
current direction. We illustrate this effect with the case of two InSb
spherical particles where we find that the ATMR amplitude can reach values of
up to 800% for a magnetic field of 5 T, which is many orders of magnitude
larger than its spintronic analogue in electronic devices. This thermomagnetic
effect could find broad applications in the fields of ultrafast thermal
management as well as magnetic and thermal remote sensing.Comment: 6 pages, 4 figure
Inflammation in stroke: the role of cholinergic, purinergic and glutamatergic signaling
The inflammatory response is a major factor in stroke pathophysiology and contributes to secondary neuronal damage in both acute and chronic stages of the ischemic injury. Recent work in experimental cerebral ischemia has demonstrated the involvement of neurotransmitter signaling in the modulation of neuroinflammation. The present review discusses recent findings on the therapeutic potential and diagnostic perspectives of cholinergic, purinergic and glutamatergic receptors and transporters in experimental stroke. It provides evidence of the role of neurotransmission signaling as a promising inflammatory biomarker in stroke. Finally, recent molecular imaging studies using positron emission tomography of cholinergic receptors and glutamatergic transporters are outlined along with their potential as novel anti-inflammatory therapy to reduce the outcome of cerebral ischemia.We acknowledge financial support by MINECO SAF2014-54070-JIN (A.M.) and SAF2016-75292-R (C.M.)
Effect of <em>Helicobacter pylori</em> on Tight Junctions in Gastric Epithelia
Molecular complexes grouped under the names of tight, adherent or gap junction regulate the flow of water, ions and macromolecules through epithelium paracellular spaces. The main constituents of tight junctions are claudins, a family of 26 different proteins whose expression and distribution are tissue specific but varies in tumors. A change in claudin 1, 3, 4, 5, 6, 7, 9 and 18 expression, that contributes to lose epithelial cohesion, has been associated to enhanced cell proliferation, migration, and invasiveness in gastric neoplastic tissue. Chronic inflammation process induced by H. pylori infection, a major risk factor for gastric cancer development, disrupts tight junctions via CagA gene, Cag pathogenicity island, and VacA, but the effect upon the epithelial barrier of H. pylori lipopolysaccharides or H. pylori-induced up-regulation of mTOR and ERK signaling pathways by microRNA-100 establishes new concepts of proof
Variable-Angle Phase-Shifted PWM for Multilevel Three-Cell Cascaded H-bridge Converters
Multilevel cascaded H-bridge converters have become a mature technology for applications where high-power medium ac voltages are required. Normal operation of multilevel cascaded H-bridge converters assumes that all power cells have the same dc voltage, and each power cell generates the same voltage averaged over a sampling period using a conventional phase-shifted pulse width modulation (PWM) technique. However, this modulation method does not achieve good results under unbalanced operation per H-bridge in the power converter, which may happen in grid-connected applications such as photovoltaic or battery energy storage systems. In the paper, a simplified mathematical analysis of the phase-shifted PWM technique is presented. In addition, a modification of this conventional modulation method using variable shift angles between the power cells is introduced. This modification leads to the elimination of harmonic distortion of low-order harmonics due to the switching (triangular carrier frequency and its multiples) even under unbalanced operational conditions. The analysis is particularized for a three-cell cascaded H-bridge converter, and experimental results are presented to demonstrate the good performance of the proposed modulation method
A Hybrid Coral Reefs Optimization – Variable Neighborhood Search Approach for the Unequal Area Facility Layout Problem
The Unequal Area Facility Layout Problem (UA-FLP) is a relevant optimization problem related to industrial design, that deals with obtaining the most effective allocation of facilities, that make up the rectangular manufacturing plant layout. The UA-FLP is known to be a hard optimization problem, where meta-heuristic approaches are a good option to obtain competitive solutions. Many of these computational approaches, however, usually fall into local optima, and suffer from lack of diversity in their population, mainly due to the huge search spaces and hard fitness landscapes produced by the traditional representation of UA-FLP. To solve these issues, in this paper we propose a novel hybrid meta-heuristic approach, which combines a Coral Reefs Optimization algorithm (CRO) with a Variable Neighborhood Search (VNS) and a new representation for the problem, called Relaxed Flexible Bay Structure (RFBS), which simplifies the encoding and makes its fitness landscape more affordable. Thus, the use of VNS allows more intensive exploitation of the searching space with an affordable computational cost, as well as the RFBS allows better management of the free space into the plant layout. This combined strategy has been tested over a set of UA-FLP instances of different sizes, which have been previously tackled in the literature with alternative meta-heuristics. The tests results show very good performance in all cases
A novel multi-objective Interactive Coral Reefs Optimization algorithm for the Unequal Area Facility Layout Problem
The Unequal Area Facility Layout Problem (UA-FLP) has been widely analyzed in the literature using several heuristics and meta-heuristics to optimize some qualitative criteria, taking into account different restrictions and constraints. Nevertheless, the subjective opinion of the designer (Decision Maker, DM) has never been considered along with the quantitative criteria and restrictions. This work proposes a novel approach for the UA-FLP based on an Interactive Coral Reefs Optimization (ICRO) algorithm, which combines the simultaneous consideration of both quantitative and qualitative (DM opinion) features. The algorithm implementation is explained in detail, including the way of jointly considering quantitative and qualitative aspects in the fitness function of the problem. The experimental part of the paper illustrates the effect of including qualitative aspects in UA-FLP problems, considering three different hard UA-FLP instances. Empirical results show that the proposed approach is able to incorporate the DM preferences in the obtained layouts, without affecting much to the quantitative part of the solutions
Reestructuración del área de compras a una gestión por categorias en una empresa de cosméticos del sector industrial
Dadas las condiciones actuales del área de compras de la empresa del sector cosmético en estudio, se propuso como objetivo principal plantear un modelo de gestión por categoría para el área de compras con las bases para generar un mayor valor a la compañía teniendo claro que este departamento gestiona gran parte de los gastos operativos y tendría un importante impacto en los resultados financieros; para esto se realizó un análisis y diagnóstico de los subprocesos que involucran la operación de compras, lo cual nos permitirá detectar las oportunidades de mejora y de acuerdo a nuestra propuesta generar mayor ahorros, valor en los procesos operativos y transaccionales del área, maximizar la rentabilidad al negociar por volumen, disminuir gastos innecesarios, evitar la duplicidad de funciones. El modelo propone reestructurar las funciones de los compradores por categorías a nivel corporativo con el apoyo de un software que aporte con sus herramientas como el módulo de sourcing, catálogos, contratos, etc, y por tanto disminuya la carga operativa y centre al comprador en negociar y buscar ahorros para la empresa y la posicionara como una empresa a la vanguardia y de acuerdo preparada para afrontar la coyuntura actual de un mercado muy competitivo
SPASMOLYTIC, ANTI-INFLAMMATORY, AND ANTIOXIDANT ACTIVITY OF SALVIA GESNERIFLORA LINDLEY
Background: Salvia gesneriflora Lindley is employed in traditional Mexican medicine for the treatment
of several diseases.
Materials and Methods: The chromatographic profile of three extracts (SgH, SgD and SgM) of this
plant allowed the identification of 11 components in SgH, the presence of rosmarinic (1), chlorogenic (2)
and caffeic (3) acids and quercetin glucoside (4) in SgM and of ursolic acid (5) in SgD. The spasmolytic
(electrically induced contractions of guinea-pig ileum), anti-inflammatory (edema in mouse ear) and
antioxidant potential (DPPH, ABTS and FRAP assays) of the extracts were evaluated.
Results: SgM showed the highest percentage of relaxation (80.67 ± 1.633%) with no significant
difference (
Real-Time Selective Harmonic Mitigation Technique for Power Converters Based on the Exchange Market Algorithm
Hand-in-hand with the smart-grid paradigm development, power converters used in
high-power applications are facing important challenges related to efficiency and power quality.
To overcome these issues, the pre-programmed Pulse-Width Modulation (PWM) methods have
been extensively applied to reduce the harmonic distortion with very low power switching losses
for high-power converters. Among the pre-programmed PWM techniques, Selective Harmonic
Elimination (SHE) has been the prevailing solution, but recently, Selective Harmonic Mitigation
(SHM) stands as a superior alternative to provide further control of the harmonic spectrum with
similar losses. However, the large computational burden required by the SHM method to find a
solution confines it as an off-line application, where the switching set valid solutions are pre-computed
and stored in a memory. In this paper, for the first time, a real-time implementation of SHM using an
off-the-shelf mid-range microcontroller is presented and tested. The Exchange Market Algorithm
(EMA), initially focused on optimizing financial transactions, is considered and executed to achieve
the SHM targets. The performance of the EMA-based SHM is presented showing experimental results
considering a reduced number of switching angles applied to a specific three-level converter, but the
method can be extrapolated to any other three-level converter topology.Ministerio de Ciencia e Innovación de España TEC2016-78430-RJunta de Andalucía P18-RT-1340Fondo Nacional de Investigación de Qatar NPRP 9-310-2-13
Prevalence of Child-Adolescent Chronic Pathologies in Cantabria (Spain)
Objective: The study of child-adolescent chronic pathologies (CACPs) is a relevant aspect for public health and this knowledge is necessary for prevention and control. Our objective was to analyze the prevalence and distribution of the main CACPs in the region of Cantabria (Spain).
Methodology: The stratified data were obtained from the whole child and adolescent population treated by the Cantabria Health Service in the year 2019. The prevalence of the most frequent CACPs and their differences based on sex, urban non-urban location and levels of complexity and risk were assessed. The statistical analysis was performed with the SPSS program.
Results: 90,163 people aged from birth to 17-year-olds were analyzed (48.7% girls and 51.3% boys). At least one CACP was present in 29.1% of the population studied (26,234). CACPs were less prevalent in girls (25.5%) than in boys (32.6%), (?2, p <0.001; OR: 0.708; IC 95%: 0.688-0.729). The two most common CACPs were: asthma (16.7%) and attention deficit hyperactivity disorder (6.3%). Multimorbidity occurred in 1,978 girls (4.5%) and in 2,916 boys (6.3%). Those chronic pathologies were less prevalent in urban areas (26.5%) than in non-urban areas (28.0%), (?2, p <0.001; OR: 1.037; 95% CI: 1.023-1.052). CACPs level of complexity was slightly higher in girls and in non-urban locations. The level of risk was similar when sex and location where compared.
Conclusion: CACPs were very common in the age group studied. Our data indicate that not only is there a need for a greater number of descriptive studies, but also a greater accuracy on the clinical records of CACPs. These actions would allow the implementation of effective programs for prevention and early detection of CACPs and better treatment and control, once they are diagnosed
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