Immunosensor Interface Based on Physical and Chemical Immunogylobulin G Adsorption onto Mixed Self-Assembled Monolayers

An immunosensor interface based on mixed hydrophobic self-assembled monolayers (SAMs) of methyl and carboxylic acid terminated thiols with covalently attached human Immunoglobulin G (hIgG), is investigated. The densely packed and organised SAMs were characterised by contact angle measurements and cyclic voltammetry. The effect of the non-ionic surfactant, Tween 20, in preventing nonspecific adsorption is addressed by ellipsometry during physical and covalent hIgG immobilization on pure and mixed SAMs, respectively. It is clearly demonstrated that nonspecific adsorption due to hydrophobic interactions of hIgG on methyl ended groups is totally inhibited, whereas electrostatic/hydrogen bonding interactions with the exposed carboxylic groups prevail in the presence of surfactant. Results of ellipsometry and Atomic Force Microscopy, reveal that the surface concentration of covalently immobilized hIgG is determined by the ratio of COOH/CH3-terminated thiols in SAM forming solution. Moreover, the ellipsometric data demonstrates that the ratio of bound anti-hIgG/hIgG depends on the density of hIgG on the surface and that the highest ratio is close to three. We also report the selectivity and high sensitivity achieved by chronoamperometry in the detection of adsorbed hIgG and the reaction with its antibody.

Efecto de counter diez g (Terbufos) y fertilizante (N-P) sobre los nem��todos asociados a caf�� en vivero

El caf�� (coffea ar��biga L.) representa uno de los cultivos de mayor importancia en Nicaragua Este cultivo se ve afectado por nematodos fitoparasito de los g��neros Meloidogyne Spp. Pratylenchus spp0, y Rotylenchulus spp. Se prob�� el efecto de combinaciones del nematicida counter 10 G y fertilizante N-P sobre los nematodos fitoparasito con un ensayo en el Centro Experimental del Caf�� Mauricio L��pez Mungu��a���, Masatepe entre los meses de abril y Octubre de 1986. El dise��a utilizado fue en bifactorial en bloques completos al azar con cuatro repeticiones. Los tratamientos fueron al nematicida counter 10 G (terbufos) en dosis de 0; 017: 0.25 y 0, 32 gr de la planta; el fertilizante N-P de la f��rmula 18-46 o en dosis de 0.5 y 10 gr/planta, aplicados sobre y en combinaci��n lo que se Hizo un total de 12 tratamientos. la aplicaci��n del nematicida se hizo una sola vez y el fertilizante en dos ocasiones d. A los 55 y 100 DDA se midi�� el numero de nematodos en el suelo (Meloidogyne spp., Rotylenchulus spp, y pratylenchus spp) nematodos en las ra��ces (Meloidogyne spp), altura de planta, Numero de hojas y peso de ra��z. Los resultados de este ensayo demostraron qu�� el nematicida tuvo efecto sobre Rotylenchulus spp y Rotylenchulus spp. Pero no sobre Meloidogyne spp en el suelo y en la ra��z: No se encontr�� ning��n defecto del fertilizant4e sobre las poblaciones de nematodos. Las combinaciones de nematicida-fertilizante tuvieron un efecto de amplia variabilidad sobre las poblaciones de nematodos lo que dificulto la recomendaci��n de una determinada combinaci��n: La dosis de fertilizantes que resulto con los mejores promedios sobre las variables altura de la planta, N��mero de hojas y peso de ra��z fue la de 5gr, /planta Se encontr�� una correlaciona negativa significativa entre el g��nero Meloidogyne spp y la altura de la plata a los 55 DDA, no observ��ndose estos mismos resultados a los 100 DDA: tambi��n se encontr�� una correlaci��n positiva significativa entre el n��mero de Meloidogyne spp, del suelo y de la ra��z a los 55 y 100 DDA; entre pratylenchus y rotylenchulus a los 55 DDA y entere el n��mero de N��dulos causados por Meloidogyne a los 55 DDA y el peso de la Ra��z a los 100 DDA.

Dios entre las m��nadas : la centralidad del tema de Dios en algunas tesis metaf��sicas de G. W. Leibniz

Resumen: En el presente trabajo buscaremos introducir ciertas tesis distintivas del pensamiento de Leibniz en lo que respecta a su metaf��sica subrayando el papel de Dios en cada una de ellas. Fundamentalmente, las tesis a tratar son la teor��a de las m��nadas y dos teor��as que se siguen de ella: la de la armon��a preestablecida y la del mejor de los mundos posibles. Adem��s, buscaremos mostrar que las pruebas de la existencia de Dios (o al menos dos de ellas: el denominado ���argumento cosmol��gico��� y el denominado ���ontol��gico���), poseen subyacentemente una fundamentaci��n metaf��sica. En este sentido, no nos centraremos en las pruebas mismas sino en su fundamentaci��n.

Observaciones pr��cticas del uso del Disyston diez g. en el control de Sogata oryzicola M. en Nicaragua

El Disyston 10 G. es un insecticida sistemico selectivo y act��a por contacto, ��nicamente sobre plagas que viven en el suelo cuando el producto se ha disuelto. Aunque es muy estable y por lo tanto su residualidad muy prolongada, se puede aplicar en todo cultivo 70 d��as antes de la cosecha y se evita de esta manera repetir aplicaciones, lo cual significa beneficios econ��micos. EL buen control obtenido de S. oryzicola, usando este insecticida en el cultivo del arroz, ha proporcionado beneficios econ��micos dignos de tomarse en cuenta. As�� mismo, facilita el aprovechamiento del control biol��gico natural que para los casos aqu�� expuestos fue excelente. El control biol��gico inducido es de esperarse que tambi��n se realice. Para el caso especifico del arroz este insecticida debe usarse en los 80 d��as antes de la cosecha, dependiendo del grado de infestacion de S. oryzicola. Ademas de los insectos chupadores que controla, tambi��n resulta efectivo contra insectos que se movilizan en o debajo de la superficie del suelo, manifestando al mismo tiempo un efecto secundario sobre nematodos. Su aplicaci��n tiene la ventaja sobre las formas convencionales, en que por ser granulado y con suficiente peso no es arrastrado por el viento de regular intensidad, los cuales resultar��an desastrosos para formulaciones emulsionables y en polvo. Durante se realizaron los recuentos, la S. oryzicola mantuvo niveles reducidos, ayudando en esta forma a mantener los predadores y par��sitos, los cuales emigrar��an, si la S. oryzicola se eliminara totalmente. Este bajo nivel de poblaci��n que permaneci�� en la plantaci��n no fue suficiente para provocar la aparici��n de s��ntomas de Hoja Blanca en el cultivo y en el grado necesario para disminuir la producci��n de grano.

Numerical simulation of g-jitter effects on half floating zone convection under microgravity environment

The g-jitter effects on the thermocapillary convection in liquid bridge of floating half zone were studied by numerical simulation for unsteady and axi-symmetric model in the cylindrical coordinate system. The g-jitter field was given by a steady microgravity field in addition to an oscillatory low-gravity field, and the effects on the flow field, temperature distribution and free surface deformation were analyzed numerically.

G-jitter effects on half floating-zone convection in intermediate-frequency range

The g-jitter influence on thermocapillary convection and critical Marangoni number in a liquid bridge of half-floating rone was discussed in the low frequency range of 0.4 to 1.5 Hz in a previous paper. This paper extended the experiments to the intermediate frequency range of 2 to 18 Hz, which htrs often been recorded as vibration environment of spacecrafts. The experiment was completed on the deck of a vibration machine, which gave a periodical applied acceleration to simulate the effects of g-jitter. The experimental results in the intermediate frequency range are different from that in the low frequency range. The velocity field and the shape of the free surface have periodical fluctuations in response to g-jitter. The amplitude of the periodical varying part of the temperature response decreases obviously with increasing frequency of g-jitter and vanishes almost when the frequency of g-jitter is high enough. The critical Marangoni number is defined to describe the transition from a periodical convection in response to g-jitter to an oscillatory convection due to internal instability, and will increase with increasing g-jitter frequency. According to the spectral analysis, it can be found that the oscillatory part of temperature is a superposition of two harmonic waves if the Marangoni number is larger than a critical value.

Effects of g-jitter on the critical marangoni number

A half floating zone is fixed on a vibrational deck, which supports a periodical applied acceleration to simulate the effect of g-jitter. This paper deals with the effects of g-jitter on the fluid fields and the critical Marangoni number, which describes the transition from a forced oscillation of thermocapillary convection into an instability oscillatory convection in a liquid bridge of half floating zone with top rod heated. The responses of g-jitter field on the temperature profiles and flow pattern in the liquid bridge were obtained experimentally. The results indicated that the critical Marangoni number decreases with the increasing of g-jitter effect and is slightly smaller for higher frequency of g-jitter with fixed strength of applied gravity.

Quantum and variational monte-carlo interaction potentials for li2 (x1-sigma-g+)

<span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">Optimized trial functions are used in quantum Monte Carlo and variational Monte Carlo calculations of the Li</span><sub style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">2</sub><span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">(X&nbsp;</span><sup style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">1</sup><span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">&Sigma;</span><sup style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">+</sup><sub style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">g</sub><span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">) potential curve. The trial functions used are a product of a Slater determinant of molecular orbitals multiplied by correlation functions of electron&mdash;nuclear and electron&mdash;electron separation. The parameters of the determinant and correlation functions are optimized simultaneously by reducing the deviations of the local energy&nbsp;</span><em style="border: 0px; font-size: 13px; margin: 0px; padding: 0px; vertical-align: baseline; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; line-height: 20px; text-align: justify; word-spacing: -1px">E</em><sub style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">L</sub><span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">&nbsp;(</span><em style="border: 0px; font-size: 13px; margin: 0px; padding: 0px; vertical-align: baseline; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; line-height: 20px; text-align: justify; word-spacing: -1px">E</em><sub style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">L</sub><span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">&nbsp;��� &Psi;</span><sup style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">&minus;1</sup><sub style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">T</sub><em style="border: 0px; font-size: 13px; margin: 0px; padding: 0px; vertical-align: baseline; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; line-height: 20px; text-align: justify; word-spacing: -1px">H</em><span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">&Psi;</span><sub style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">T</sub><span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">, where &Psi;</span><sub style="border: 0px; font-size: 0.75em; margin: 0px; padding: 0px; line-height: 0; color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; text-align: justify; word-spacing: -1px">T</sub><span style="color: #2e2e2e; font-family: 'Arial Unicode MS', 'Arial Unicode', Arial, 'URW Gothic L', Helvetica, Tahoma, sans-serif; font-size: 13px; line-height: 20px; text-align: justify; word-spacing: -1px">&nbsp;denotes a trial function) over a fixed sample. At the equilibrium separation, the variational Monte Carlo and quantum Monte Carlo methods recover 68% and 98% of the correlation energy, respectively. At other points on the curves, these methods yield similar accuracies.</span>

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Starting Nozzle Flow Simulation Using K-G Two-Equation Turbulence Model

The starting process of two-dimensional nozzle flows has been simulated with Euler, laminar and k - g two-equation turbulence Navier-Stokes equations. The flow solver is based on a combination of LUSGS subiteration implicit method and five spatial discretized schemes, which are Roe, HLLE, MHLLE upwind schemes and AUSM+, AUSMPW schemes. In the paper, special attention is for the flow differences of the nozzle starting process obtained from different governing equations and different schemes. Two nozzle flows, previously investigated experimentally and numerically by other researchers, are chosen as our examples. The calculated results indicate the carbuncle phenomenon and unphysical oscillations appear more or less near a wall or behind strong shock wave except using HLLE scheme, and these unphysical phenomena become more seriously with the increase of Mach number. Comparing the turbulence calculation, inviscid solution cannot simulate the wall flow separation and the laminar solution shows some different flow characteristics in the regions of flow separation and near wall.