On‐the‐Spot Immobilization of Quantum Dots,Graphene Oxide,and Proteins via Hydrophobins

Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications.     

Supermodularity and subadditivity properties of the entropy on themajorization lattice

We prove that the entropy is a supermodular and subadditive function on the lattice of all n-dimensional probability distributions, ordered according to the partial order relation defined by majorization among vectors     

Characterization of colloidal polymer particles through stability ratio measurements

We propose a general methodology for the estimation of the doublet formation rate constant (proportional to the stability ratio of primary particles) in colloidal dispersions from measurements obtained by common optical techniques, such as dynamic light scattering, static light scattering (nephelometry) or turbidimetry. In contrast to previous approaches relying on the initial slopes of the measured quantities, such as the mean hydrodynamic radius, scattered light intensity or turbidity, we introduce a transformation of the measurables to properly scaled quantities, which grow linearly in time with a slope proportional to the doublet formation rate. Analysis of systematic and random errors allows one to control the error in the estimated value of the aggregation rate. Using this approach, we measured the aggregation rate constant of colloidal polymer particles prepared by surfactant-free emulsion copolymerization of styrene and 2-hydroxyethyl methacrylate (HEMA). It was found that the stability ratio at constant ionic strength decreases with increasing dilution of the original polymer latex. This can be explained by the presence of non-reacted stabilizing species (most likely oxidized HEMA) that desorb from the particle surface upon latex dilution and thus diminish the repulsive interactions between particles. In order to check if the stability of latex particles is influenced by reversibly adsorbed species it is always necessary to perform aggregation experiments at various dilutions.     

Reasons for the autonomous community of Aragon's position against the Ebro transfer as envisaged in the national hydrological plan

The present paper outlines the views of the Government of Aragon on the National Hydrological Plan of Spain. It concludes that the transfer of water from the Ebro River will accentuate the differences among some regions of Spain in terms of their development potentials. It will unquestionably constrain the future development of regions that are already disadvantaged, such as Aragon. Alternatives are proposed where the regions in need of water can obtain it, but without adversely affecting the economic, social and environmental sustainability of the region and the people of Aragon.     

Analysis and Design of Robust Controllers Using the Interval Diophantine Equation

In this paper the design of pole placement feedback controllers for interval plants is addressed within an Interval Analysis framework. Three main topics connected by the concept of interval Diophantine equation are treated: a relatively straightforward investigation about robust coprimeness of interval polynomials, a reliable computing approach for the design of pole placement controllers in the presence of inaccuracies of interval type, and the design of robust controllers with regional pole placement specifications. After explicitly characterizing a convex subset of robust controllers, the problem of designing non-fragile controllers is formulated as a design centering problem, which is then solved by a global optimization algorithm. Numerical examples illustrate the main characteristics of the approach proposed.This paper has been partially supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico–Brazil.     

On the impact of physical layer awareness on scheduling and resource allocation in broadband multicellular IEEE 802.16 systems [Radio Resource Management and Protocol Engineering for IEEE 802.16]

Multicellular networks based on the IEEE 802.16 standard appear to be very promising candidates to provide end users with broadband wireless access. However, they also pose interesting challenges in terms of radio resource management, where several design choices are not specified in the standard, intentionally left open to implementors. For this reason, we focus in this article on scheduling and resource allocation, and investigate how they could operate in a cross-layer fashion. In particular, we describe the principles of joint scheduling and resource allocation for IEEE 802.16 operating in AMC mode, and discuss the critical role played by physical layer considerations, especially intercell interference estimation and channel state awareness, in the obtained performance. This leads to identifying key open issues and possible general solutions     

A new pneumatic bearing dynamometer for power input measurement in stirred tanks

A turntable dynamometer has been constructed for the accurate measurement of power input and mixing applications in bench stirred tank reactors. The main feature of this device is a pneumatic bearing with complementary conical parts. The conical pneumatic bearing permitted to apply eccentric loads without affecting its stability. The static friction torque in the pneumatic bearing was very small, 4 × 10^?4 Nm, and can be neglected in the experimental ranges of measured torques, i.e. from 5 × 10^?3 to 2.21 Nm. In accordance with the instrumentation used, the deviations obtained with the apparatus are less than 10% at low torque readings. At moderate torques, deviations lower than 1% are routinely obtained. Several power input measurements show that the obtained data scatter is lower than 2.5%. The power input response in the turbulent regime is in agreement with dimensional analysis: the power input depends on the cube of the impeller speed. In addition, data obtained with a turbine impeller under ungassed conditions agree with the predictions of a published correlation, which takes into account several geometrical parameters.     

Inspection and Process of Tension of Cables of General Rafael Urdaneta Bridge

In 1997 and 1999, inspection works were carried out in the 384 cable stays of the six central piers of General Rafael Urdaneta Bridge, located in Maracaibo, Venezuela. Inspection indicated the presence of water and significant settlings in the sockets of the cables and corrosion along each cable and socket. The tension of the cables was also measured, and differences of up to 30% in the tension of the cables of some of the 24 groups corresponding to the six central piers (four groups of 16 for each pier) were found. The results suggested the need to retension the cables. This paper shows the outcome of the inspection and indicates the procedure and results of the process of retension, finished in July 2000.     

A new amperometric biosensor for fructose determination based on epoxy-graphite-TTF-TCNQ-FDH-biocomposite

In this work a novel amperometric biosensor for fructose determination in solutions was developed. The device was constructed by the incorporation of a tetrathiofulvalene-tetracyanoquinodimethane organic conducting salt and fructose dehydrogenase enzyme, include in a polymeric matrix of epoxy resin and graphite powder. Because of the electrocatalytic function of the salt, the direct transfer of the electron between the reduced prosthetic group (PQQH₂) of the enzyme and the transducing material, was verified at a low working potential (150 mV vs. Ag/AgCl), where the interfering reactions were minimized. The response time at 90% of the steady state value was less than 20 s. The current response was directly proportional to the D-fructose concentration from 0.01 to 0.3 mmol/l with a detection limit of 0.005 mmol/l (signal/noise of 3) and a sensitivity of 1.9985 μA/mmol. The biosensor sensitivity diminishes when its surface is not polished between successive determinations, and remains constant (rsd=1.85, n=10) when the surface is polished between determinations. The effects of temperature and pH on the biosensor response were studied and analyzed; also the properties of the enzyme (Km _ap, I _max, Q₁₀) were determinate in this work. The biosensor was used to determine fructose in high fructose syrups and there were not significant differences between these results and those obtained by HPLC (p≤0.05). During 4 months, in intermittent determinations the biosensor kept 100% of its original sensitivity and after 18 months stored at 4°C, it only lost 32% of its sensitivity. The simplicity, low working potential, high stability and good performance of this biosensor shows a great potential for its use in the fructose determination.     

Carbonitriding of Clay: Relation between the Weight Loss and Crystalline Phases during Reaction

β'-Sialons are phases of the Si-Al-O-N system. The carbonitriding of clays and kaolins is a preparation method. The reaction mechanism of clay carbonitriding is verified by means of the relation among crystalline phases formed and the weight loss produced in the samples during the reaction. Two clays were previously mixed with carbon black and pressed into pellets, flowing through N₂ atmosphere, at five temperatures within the range 1335–1427°C. The phases formed (XRD)—mullite, SiC, β'A-sialon, and oxynitrides—were related to the weight loss measured in the pellet independently of reaction temperature and time. The β'A-sialon and the nitrogenous phases were formed from SiC and mullite. A z value decrease for β'A-sialon was observed during reaction progression.