Manipulating light at distance by a metasurface using momentum transformation

A momentum conservation approach is introduced to manipulate light at distance using metasurfaces. Given a specified field existing on one side of the metasurface and specified desired field transmitted from the opposite side, a general momentum boundary condition is established, which determines the amplitude, phase and polarization transformation to be induced by the metasurface. This approach, named momentum transformation, enables a systematic way to synthesize metasurfaces with complete control over the reflected and transmitted fields. Several synthesis illustrative examples are provided: a vortex hypergeometric-Gaussian beam and a "delayed-start" accelerated beam for Fresnel region manipulation, and a pencil beam radiator and a holographic repeater for Frauenhofer region manipulation

FPGA-based implementation of the back-EMF symmetric-threshold-tracking sensorless commutation method for brushless DC-machines

The operation of brushless DC permanent-magnet machines requires information of the rotor position to steer the semiconductor switches of the power-supply module which is commonly referred to as Brushless Commutation. Different sensorless techniques have been proposed to estimate the rotor position using current and voltage measurements of the machine. Detection of the back-electromotive force (EMF) zero-crossing moments is one of the methods most used to achieve sensorless control by predicting the commutation moments. Most of the techniques based on this phenomenon have the inherit disadvantage of an indirect detection of commutation moments. This is the result of the commutation moment occurring 30 electrical degrees after the zero-crossing of the induced back-emf in the unexcited phase. Often, the time difference between the zero crossing of the back-emf and the optimal current commutation is assumed constant. This assumption can be valid for steady-state operation, however a varying time difference should be taken into account during transient operation of the BLDC machine. This uncertainty degrades the performance of the drive during transients. To overcome this problem which improves the performance while keeping the simplicity of the back-emf zero-crossing detection method an enhancement is proposed. The proposed sensorless method operates parameterless in a way it uses none of the brushless dc-machine parameters. In this paper different aspects of experimental implementation of the new method as well as various aspects of the FPGA programming are discussed. Proposed control method is implemented within a Xilinx Spartan 3E XC3S500E board

Impact of season of harvest on in vitro gas production and dry matter degradability of Acacia saligna leaves with inoculum from three ruminant species

In vitro gas production (IVGP) and dry matter degradability (IVDMD) of Acacia saligna leaves (ASL) from four seasons were studied under arid Egyptian conditions as a 4×3 factorial experiment (4 seasons×3 ruminant species). Incubations were completed using rumen liquid collected immediately after slaughter from sheep, cattle and buffalo, in order to investigate differences among ruminants in their ASL fermentation capacity. Samples of ASL were collected during the last 2 months of each season, being autumn, winter, spring and summer (between the 5th and 12th week of each season). Dried samples of ASL were incubated for 24 h in each of the three buffered rumen liquors, using a syringe technique, to determine IVGP and IVDMD. The crude protein content of ASL was lower (P<0.01) in summer (143 g/kg DM) than autumn (171 g/kg DM), winter (177 g/kg DM) and spring (182 g/kg DM). In winter, ASL had lower neutral detergent fibre, acid detergent fibre, acid detergent lignin and cellulose than in other seasons (P<0.05), but there were no differences among seasons in ash and hemicellulose contents. Condensed tannin (CT, as quebracho tannin equivalent) contents of ASL were higher (P<0.001) in summer (113 g/kg DM) versus the other seasons, with the lowest value during winter (63 g/kg DM). Gas production after 24 h was higher (P<0.05) with buffalo rumen fluid, versus cattle or sheep, in all seasons except winter. IVGP with buffalo rumen fluid was not affected by season but, with cattle and sheep, IVGP was higher (P<0.01) in winter. IVDMD was higher in winter and spring, and lower in summer and autumn, within all species, and higher (P<0.001) values were general with buffalo versus other species. IVGP was positively (P<0.05) correlated with IVDMD, but there was no consistent relationship between IVGP or IVDMD and chemical composition of ASL. Rumen fluid from buffalo, cattle and sheep have different capacities to ferment A. saligna leaves, and differences among species were smallest in winter, when the fibre and CT contents of ASL were lower. © 2005 Elsevier B.V. All rights reserved

General Metasurface Synthesis Based on Susceptibility Tensors

A general method, based on susceptibility tensors, is proposed for the synthesis of metasurfaces transforming arbitrary incident waves into arbitrary reflected and transmitted waves. The proposed method exhibits two advantages: 1)it is inherently vectorial, and therefore better suited for full vectorial (beyond paraxial) electromagnetic problems, 2) it provides closed-form solutions, and is therefore extremely fast. Incidentally, the method reveals that a metasurface is fundamentally capable to transform up to four independent wave triplets (incident, reflected and refracted waves). In addition, the paper provides the closed-form expressions relating the synthesized susceptibilities and the scattering parameters simulated within periodic boundary conditions, which allows one to design the scattering particles realizing the desired susceptibilities. The versatility of the method is illustrated by examples of metasurfaces achieving the following transformations: generalized refraction, reciprocal and non-reciprocal polarization rotation, Bessel vortex beam generation, and orbital angular momentum multiplexing

The Role of miR-590-3p in Regulating Human Epithelial Ovarian Cancer Development

Epithelial ovarian cancer (EOC) has the highest mortality rate among all gynecological malignancies. Early detection and intervention remain key to patient prognosis fueling the search for reliable biomarkers. MicroRNAs (miRNAs) are small non-coding RNAs that play a crucial regulatory role within the cell and their dysregulation is associated with many diseases including cancer. In this study, using several well-characterized human EOC cells lines, EOC patient tissue and serum samples, and an in vivo mouse model we investigated the role and mechanism of miR-590-3p in promoting ovarian cancer. Our findings indicate that miR-590-3p levels were elevated in both clinical ovarian tumor samples, as well as in the blood serum of the same patients than in subjects with benign gynecological disorders. Overexpression of miR-590-3p in multiple EOC cells led to an increase in cell proliferation, migration, invasion, colony formation, and spheroid formation. In addition, injection of cells overexpressing mir-590 precursor into nude mice increased the dissemination of the tumor nodules, and formed larger tumors compared to control groups. cDNA microarray for cells overexpressing mir-590 revealed Forkhead box A2 (FOXA2) and Versican (VCAN) as one of the top downregulated and upregulated genes, respectively. Interestingly, ChIP-qPCR revealed that FOXA2 binds to VCAN promoter, and overexpression of FOXA2 reduced, while knockout of FOXA2 increased, VCAN mRNA and protein levels. Moreover, luciferase assay confirmed that miR-590-3p is directly targeting the 3UTR of FOXA2 and cyclin G2 (CCNG2) to suppress their expressions. In addition, silencing of CCNG2 mimicked the effect of miR-590-3p and induced cell proliferation, migration and invasion, while CCNG2 overexpression reversed this phenotype. In addition, mir-590 precursor increased the -catenin activity in TOPflash assays, whereas, knockdown of -catenin blocks the effect of mir-590 on spheroid formation. Altogether, our results demonstrate that miR-590-3p has tumor-promoting effects in EOCs via targeting FOXA2 and CCNG2 which leads to induction of VCAN and -catenin signaling

Nuevos fitocompuestos activos naturales para el tratamiento y prevención de diarreas infecciosas

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, Departamento de Microbiología II, leída el 24-07-2015Las infecciones entéricas siguen siendo uno de los problemas más importantes de salud pública. La diarrea infecciosa es a nivel mundial la segunda causa de morbilidad y mortalidad infantil, con 4,6 millones de muertes de los aproximadamente un billón de episodios de diarrea al año reportados en niños. Según informes recientes de la OMS, 1,9 millones de niños menores de cinco años siguen muriendo de estas enfermedades cada año. Los principales síntomas clínicos de las infecciones entéricas incluyen los síntomas gastrointestinales y las afecciones sistémicas, pudiendo darse sucesivamente. El principal síntoma de afectación gastrointestinal es la diarrea. Otros síntomas frecuentes son fiebre, nauseas, vómitos y dolor abdominal, en función de los patógenos microbianos. Los brotes de infecciones intestinales se producen a través de la ingestión de alimentos o agua contaminados, transmisión vía fecal oral, o por contacto directo, persona a persona. En los países en vías de desarrollo los agentes causantes de las infecciones entéricas más recurrentes son las bacterias. Escherichia coli es una bacteria anaerobia facultativa predominante en la microbiota intestinal del colon en los humanos que con el paso del tiempo se asoció a la aparición de diarreas. Las bacterias E. coli diarreicas se clasifican en seis categorías; entre ellas destaca E. coli enteropatógena, EPEC. EPEC es la causa más importante de morbilidad y mortalidad en niños menores de cinco años en los países en vías de desarrollo. EPEC se adhiere a las células intestinales y mediante un sistema de secreción denominado tipo tres, inyecta las proteínas efectoras bacterianas que se transfieren al citosol de la célula hospedadora afectando a múltiples funciones fisiológicas que en última instancia conducen a la enfermedad diarreica. EPEC se adhiere a las células intestinales formando una lesión histopatológica caracterizada por la degeneración local de las microvellosidades de absorción, la adherencia intima de la bacteria a la célula hospedadora y la formación de una estructura rica en filamentos de actina denominada pedestal. La terapia de rehidratación oral y el suplemento nutricional se deben realizar antes de administrar ningún otro agente terapéutico. Los antibioticos se requieren para el tratamiento de la gastroenteritis bacteriana en aquellos pacientes que sufren complicaciones graves, como por ejemplo pacientes donde la enfermedad se ha expandido por el organismo provocando sepsis. Generalmente, el tratamiento antimicrobiano consigue prevenir la progresión de la enfermedad. La aparición de resistencia bacteriana frente a los agentes antimicrobianos, particularmente de cepas de E. coli, se ha incrementado a nivel global. Un gran número de cepas bacterianas están mostrando ser resistentes a prácticamente todos los agentes terapéuticos disponibles. De este modo, el problema ha ido aumentando durante décadas, y hoy en día muchas infecciones comunes se están convirtiendo en infecciones difíciles o incluso imposibles de tratar, y así una infección común potencialmente mortal puede convertirse en una amenaza para la vida de la persona. Por lo tanto, hay una continua necesidad de buscar nuevos agentes antibacterianos para superar la resistencia a los antibioticos. El uso de plantas medicinales para el tratamiento de las enfermedades es una práctica arraigada en las distintas culturas desde la antigüedad. Cerca de 1.500 especies de plantas medicinales y aromáticas son ampliamente utilizadas en distintos países Europeos. En los últimos años, metabolitos secundarios como compuestos fenólicos, terpenoides, flavonoides y alcaloides han recibido una gran atención debido a sus diversas funciones biológicas. Por todo ello, en esta tesis hemos estudiado las propiedades antimicrobianas de una selección de extractos de plantas medicinales frente a diversas cepas de bacterias patógenas, 12 Gram positivas y Gram negativas en total, y 3 levaduras.Depto. de Microbiología y ParasitologíaFac. de FarmaciaTRUEunpu

Perioperative risk factors for mortality in patients with acute type A ‎aortic dissection: A retrospective analysis of a center experience ‎over 15 years

‎Background Acute type A aortic dissection (AAAD) isassociated with highmortality rateandfrequent ‎postoperative complications. This study was designed to evaluate perioperative risk ‎factors for mortality in patients with AAAD.‎ Patients and methods A retrospective analysis included 344 consecutivepatientswho underwent surgery for ‎AAAD in moderate hypothermic circulatory arrest (20-24 C°) between 2001 and 2016.‎ Results ‎ The 30-day mortality rate for all patients was 18%. Non-survivors were significantly ‎older (65.7±12.0years vs.62.0±12.5 years; p=0.034) with significantly higher Euro-score ‎II [15.4%(6.6;23.0) vs. 4.63%(2.78;9.88) p75years), coronary heart disease, previous cardiac surgery and ‎preoperative cardiopulmonary resuscitation (CPR) (p<0.05). Intraoperatively, survivors ‎had statistically shorter cardiopulmonary bypass times [163min (134;206) vs. 198 min ‎‎(150;245); p=0.001]. However, the hypothermic circulatory arrest time was similar ‎between the groups. Postoperatively, the incidence of AKI (55.9% vs. 15.2%; p<0.001), ‎stroke (27.9% vs. 12.1%; p=0.002) and sepsis (18.0% vs. 2.1%; p<0.001) were ‎significantly higher among non-survivors. The multiple logistic regression confirmed ‎that older age, previous cardiac surgery, preoperative CPR, intraoperative transfusion ‎and postoperative AKI were statistically significant independent risk factors for death ‎‎(p<0.05).‎ Conclusion The currentstudy suggested that AAADremains associated with a high mortality rate. ‎The reason for mortality and complications in patients undergoing surgical repair of ‎AAAD was multifactorial, especially older age, previous cardiac surgery, preoperative ‎CPR, transfusion, as well as postoperative AKI were considered risk factors for ‎mortality.