OPTICA GEOMETRICA

Sólo visión Proyectabl

Rigorous diffraction of an electromagnetic beam by wavelength-size slits

A rigorous modal theory for the diffraction of Gaussian beams from N slits in an otherwise perfectly plane conducting screen (line finite-grating) is presented. The case of normal incidence and T.E.-polarization is considered, i.e. the electric field is parallel to the strips. The characteristics of the far-field radiation pattern as a function of the wavelength are analyzed, particularly within the vectorial region where the influence of polarization is more important. Furthermore, the influence of the beam width and beam alignment on the transmission coefficient, on the normally diffracted energy, and on the diffraction is studied

Teoría rigurosa de la dispersión de haces gaussianos por una rejilla con sustrato metálico

Se presenta una teoría rigurosa de la dispersión de haces Gaussianos a incidencia normal y oblicua por una rejilla finita en una pantalla conductora, de espesor cero y con sustrato metálico. El sustrato puede ser el vacío o un conductor. Se considera el caso de polarización T.E., es decir, el campo eléctrico es paralelo a las rendijas. Se analiza en la región vectorial de la difracción a patrones de dispersión en función de la longitud de onda, del hacho del haz y de la posición del haz. De estos resultados se ha encontrado que el ancho de los órdenes de dispersión aumenta con la relación λ/L, donde λ es la longitud de onda y L el ancho del haz incidente. Cuando el sustrato es un conductor la ecuación de dispersión por una rejilla en reflexión predice la posición angular de los órdenes dispersados de una rejilla finita con una buena aproximación. Además, la posición angular de estos órdenes es independiente del sustrato, del ancho y de la posición del haz

A MAXWELL THEORY FOR THE SCATTERING OF TM POLARIZED

We present a rigorous theory for oblique incident Hermite-Gaussian beams, diffracted by two slits of width and separation d, in a thick metallic screen for the case of polarization TM(S). The far field spectra as a function of several opto-geometrical parameters, wavelength λ, slit width , separation d, incidence angle θ i and Hermite order m is analyzed. In the vectorial diffraction region given when λ/ >0.2, where is the incident wavelength and as a function of the separation between slits d; we have numerically analyzed: the far field spectra, the energy diffracted along the incident beam direction (E i ), and the validity of an approximate diffraction (scalar) property, namely E i = Nτ/λ.Se presenta una teoría vectorial de la difracción de haces Hermite–Gauss sobre una pantalla metálica de espesor h con dos rendijas de ancho l y separación d. los haces inciden oblicuamente con polarización TM. Estudiamos numéricamente los patrones de difracción en campo lejano como función de los parámetros opto–geométricos: longitud de onda λ, ancho de rendija l, separación d, ángulo de incidencia θ i y orden del polinomio de Hermite m. Por otra parte, en la región vectorial de la difracción dada por λ⁄l > 0.2 donde λ es la longitud de onda incidente, se analiza numéricamente la energía difractada a lo largo de la dirección del haz incidente (E i ) y la validez de la propiedad de la difracción escalar E i = Nτ/λ donde τ es el coeficiente de transmisión y N el número de rendijas.Conacy

A Novel Theory for the Scattering of P-Polarized Hermite-Gaussian Electromagnetic Beams by a Double Metallic Nano-Slit

We present a rigorous theory for oblique incident Hermite-Gaussian beams, diffracted by two optical nano-slits of width and separation d, in a thick metallic screen for the case of polarization TM (P). The far field spectra as a function of several opto-geometrical parameters, wavelength λ, slit width , separation d, incidence angle θ୧ and Hermite order m is analyzed. In the vectorial diffraction region given when λ/ >0.2, where is the incident wavelength and as a function of the separation between slits d; we have numerically analyzed: the far field spectra, the energy diffracted along the incident beam direction (E୧), and the validity of an approximate diffraction (scalar) property, namely E୧ = Nτ/λUniversidad Autónoma del Estado de Méxic

RED DE VALOR DEL MANGO Y SUS DESECHOS CON BASE EN LAS PROPIEDADES NUTRICIONALES Y FUNCIONALES

The value chain is a new concept inside the agricultural development in Mexico that involves having in mind the demands of the consumers for the development of commercialization strategies for fruits. The nutritional and functional properties can add value to food. The mango and byproducts generated during its processing or marketing are a very important source of bioactive compounds with high added value, mostly dietary fiber, micronutrients, polyphenols, carotenoids, among many others. These can be valorisated through multidisciplinary research, innovation, technology transfer, development of market studies and business plans, as well as the accompaniment during the management and implementation of functional foods in agro-business.Mango, value chain, functional food., Agribusiness,

INNOVACION DE PRODUCTOS DE ALTO VALOR AGREGADO A PARTIR DE LA TUNA MEXICANA

In the world, Mexico is the major producer of prickly pears and also has the largest number in varieties. However, in addition to its highly seasonal production, prickly pears are consumed just by a small segment of the Mexican population. Therefore, the promotion of prickly pears consumption in the form of new derivative products by emphasizing its bioactive properties seems to be a possible solution to its low consumption. Recent studies from European and Asian laboratories showed that some prickly pears varieties have a significant antioxidant activity. In Mexico, prickly pears producers are looking for new ways of commercialization. In this regard, similar studies are underway surveying those varieties from the highly producing Mexican states with the goal to develop new functional products with high added value. In addition, the use of prickly pears as a raw material for the cosmetic and pharmaceutical industries is being considered and seems to be highly promising.Prickly pears, antioxidant activity, innovation, functional food., Agribusiness,

Hepatoprotective Effect of Opuntia robusta and Opuntia streptacantha Fruits against Acetaminophen-Induced Acute Liver Damage

Acetaminophen (APAP)-induced acute liver failure (ALF) is a serious health problem in developed countries. N-acetyl-L-cysteine (NAC), the current therapy for APAP-induced ALF, is not always effective, and liver transplantation is often needed. Opuntia spp. fruits are an important source of nutrients and contain high levels of bioactive compounds, including antioxidants. The aim of this study was to evaluate the hepatoprotective effect of Opuntia robusta and Opuntia streptacantha extracts against APAP-induced ALF. In addition, we analyzed the antioxidant activities of these extracts. Fruit extracts (800mg/kg/day, orally) were given prophylactically to male Wistar rats before intoxication with APAP (500 mg/kg, intraperitoneally). Rat hepatocyte cultures were exposed to 20mmol/LAPAP, and necrosis was assessed by LDH leakage. Opuntia robusta had significantly higher levels of antioxidants than Opuntia streptacantha. Both extracts significantly attenuated APAP-induced injury markers AST, ALT and ALP and improved liver histology. The Opuntia extracts reversed APAP-induced depletion of liver GSH and glycogen stores. In cultured hepatocytes, Opuntia extracts significantly reduced leakage of LDH and cell necrosis, both prophylactically and therapeutically. Both extracts appeared to be superior to NAC when used therapeutically. We conclude that Opuntia extracts are hepatoprotective and can be used as a nutraceutical to prevent ALF

Betalain, Acid Ascorbic, Phenolic Contents and Antioxidant Properties of Purple, Red, Yellow and White Cactus Pears

Commercialization of cactus pears based on their antioxidant properties can generate competitive advantages, and these can turn into business opportunities and the development of new products and a high-value ingredient for the food industry. This work evaluated the antioxidant activities (1,1-diphenyl-2-picrylhydrazyl radical-scavenging, protection against oxidation of a β-carotene-linoleic acid emulsion, and iron (II) chelation), the content of total phenolic compounds, ascorbic acid, betacyanin, betaxanthin and the stability of betacyanin pigments in presence of Cu (II)-dependent hydroxyl radicals (OH•), in 18 cultivars of purple, red, yellow and white cactus pear from six Mexican states. Our results indicated that the antiradical activities from yellow and white cactus pear cultivars were not significantly different (p < 0.05) and were lower than the average antiradical activities in red and purple cultivars. The red cactus pear from the state of Zacatecas showed the highest antioxidant activity. The free radical scavenging activity for red cactus pears was significantly correlated (p < 0.05) to the concentration of total phenolic compounds (R2 = 0.90) and ascorbic acid (R2 = 0.86). All 18 cultivars of cactus pears studied showed significant chelating activity of ferrous ions. The red and purple cactus pears showed a great stability when exposed to OH•

Association of Epstein-Barr virus antibody titers with a human IL-10 promoter polymorphism in Japanese women

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens