Application of Ru(bpy)(3)(2+) in control and formation of gold surface nanostructure through oxidation-reduction cycling

It was studied that the nanostructure formed on a gold surface via a simple oxidation-reduction cycles (ORC) in 0.1 M KCl containing Ru(bpy)(3)(2+) with different concentrations. Atomic force microscopy (AFM) and energy-dispersed spectroscopy (EDS) were used to characterize the nanostructure formed on the gold surface. Sweep-step voltammetry and corresponding electroluminescence (ECL) response, in situ electrochemical quartz crystal microbalance (EQCM) measurement were used to monitor the ORC. procedure. It was found that the surface structure became more uniform in the presence of Ru(bpy)(3)(2+), and the surface roughness was decreasing with the increasing of Ru(bpY)(3)(2+) concentration, suggesting a simple and effective method to control the formation of nanostructure on the gold surface.

El uso de patrones geométricos para la construcción del lenguaje simbólico en estudiantes de nivel medio superior

La idea que motiva el presente trabajo se refiere a entender cómo generalizan los estudiantes de bachillerato y qué tipo de pensamiento les permite hacerlo, para ello planteamos a un grupo de estudiantes del IEMS actividades donde se debe identificar un patrón que predice una secuencia geométrica, como un primer acercamiento a la idea de generalización. Este patrón debe ser descrito de forma algebraica (fórmula). En este artículo mostraremos dos tipos de formulaciones distintas construidas por los estudiantes para abordar el problema con distintos tipos de pensamiento que nos permiten mirar aspectos que podrían determinar el éxito o fracaso del desarrollo cognitivo puesto en marcha por los estudiantes.

Characterisation of two calmodulin-like proteins from the liver fluke, Fasciola hepatica.

Calmodulin is a calcium ion-sensing signalling protein found in eukaryotics. Two calmodulin-like gene sequences were identified in an EST library from adult liver flukes. One codes for a protein (FhCaM1) homologous to mammalian calmodulins (98% identity), whereas the other protein (FhCaM2) has only 41% identity. These genes were cloned into expression vectors and the recombinant proteins were expressed in Escherichia coli. Gel shift assays showed that both proteins bind to calcium, magnesium and zinc ions. Homology models have been built for both proteins. As expected, FhCaM1 has a highly similar structure to other calmodulins. Although FhCaM2 has a similar fold, its surface charge is higher than FhCaM1. One of the potential metal ion-binding sites has lower metal-ion co-ordination capability, while another has an adjacent lysine residue, both of which may decrease the metal-binding affinity. These differences may reflect a specialised role for FhCaM2 in the liver fluke.

Mass spectrometric analysis of muscle samples to detect potential antibiotic growth promoter misuse in broiler chickens

Mass spectrometric methods were developed and validated for the analysis in chicken muscle of a range of antibiotic growth promoters: spiramycin, tylosin, virginiamycin and bacitracin, and separately for two marker metabolites of carbadox (quinoxaline-2-carboxylic acid and 1,4-bisdesoxycarbadox), and a marker metabolite of olaquindox (3-methyl-quinoxaline-2-carboxylic acid). The use of these compounds as antibiotic growth promoters has been banned by the European Commission. This study aimed to develop methods to detect their residues in muscle samples as a means of checking for the use of these drugs during the rearing of broiler chickens. When fed growth-promoting doses for 6 days, spiramycin (31.4 mu g kg(-1)), tylosin (1.0 mu g kg(-1)), QCA (6.5 mu g kg(-1)), DCBX (71.2 mu g kg(-1)) and MQCA (0.2 mu g kg(-1)) could be detected in the muscle 0 days after the withdrawal of fortified feed. Only spiramycin could consistently be detected beyond a withdrawal period of 1 day. All analytes showed stability commercial cooking process, therefore raw or cooked muscle could be used for monitoring purposes.

Conformational Change of Mitochondrial Complex I Increases ROS Sensitivity During Ischemia

Aims: Myocardial ischemia/reperfusion (I/R) is associated with mitochondrial dysfunction and subsequent cardiomyocyte death. The generation of excessive quantities of reactive oxygen species (ROS) and resultant damage to mitochondrial enzymes is considered an important mechanism underlying reperfusion injury. Mitochondrial complex I can exist in two interconvertible states: active (A) and deactive or dormant (D). We have studied the active/deactive (A/D) equilibrium in several tissues under ischemic conditions in vivo and investigated the sensitivity of both forms of the heart enzyme to ROS.

Results: We found that in the heart, t½ of complex I deactivation during ischemia was 10?min, and that reperfusion resulted in the return of A/D equilibrium to its initial level. The rate of superoxide generation by complex I was higher in ischemic samples where content of the D-form was higher. Only the D-form was susceptible to inhibition by H2O2 or superoxide, whereas turnover-dependent activation of the enzyme resulted in formation of the A-form, which was much less sensitive to ROS. The mitochondrial-encoded subunit ND3, most likely responsible for the sensitivity of the D-form to ROS, was identified by redox difference gel electrophoresis.

Innovation: A combined in vivo and biochemical approach suggests that sensitivity of the mitochondrial system to ROS during myocardial I/R can be significantly affected by the conformational state of complex I, which may therefore represent a new therapeutic target in this setting.

Conclusion: The presented data suggest that transition of complex I into the D-form in the absence of oxygen may represent a key event in promoting cardiac injury during I/R.

Identity and Geopolitics in Hergé's Adventures of Tintin

This is a study of identity and geopolitics in Hergé's Adventures of Tintin, a series of adventure comics created from 1929 to 1976. The Tintin comics became increasingly popular throughout the mid-twentieth century, and their creator, Hergé, is still a subject of intrigue in the press and popular publications. Recent work in popular geopolitics has pioneered the use of comics as a new type of source material in critical geography. Hergé's approach to the comics format combines an iconic protagonist with detailed and textured environments that draw upon some of the geopolitical discourses of the twentieth century. Three forms of geopolitical meaning are identified within the Tintin comics: discourses of colonialism, European pre-eminence and anti-Americanism. These overlapping trends amount to different facets of one single discourse, which places European ideologies at the centre of its world-view. This is highlighted by focusing on three geographical spaces of the Tintin series, and by contextualising the life and selected works of Hergé. © 2009 Taylor & Francis.

Electromagnetic rogue waves in beam-plasma interactions

The occurrence of rogue waves (freak waves) associated with electromagnetic pulse propagation interacting with a plasma is investigated, from first principles. A multiscale technique is employed to solve the fluid Maxwell equations describing weakly nonlinear circularly polarized electromagnetic pulses in magnetized plasmas. A nonlinear Schrödinger (NLS) type equation is shown to govern the amplitude of the vector potential. A set of non-stationary envelope solutions of the NLS equation are considered as potential candidates for the modeling of rogue waves (freak waves) in beam-plasma interactions, namely in the form of the Peregrine soliton, the Akhmediev breather and the Kuznetsov-Ma breather. The variation of the structural properties of the latter structures with relevant plasma parameters is investigated, in particular focusing on the ratio between the (magnetic field dependent) cyclotron (gyro-)frequency and the plasma frequency. © 2013 IOP Publishing Ltd.

Quantum state storage and processing for polarization qubits in an inhomogeneously broadened Λ-type three-level medium

We address the propagation of a single photon pulse with two polarization components, i.e., a polarization qubit, in an inhomogeneously broadened "phaseonium" \Lambda-type three-level medium. We combine some of the non-trivial propagation effects characteristic for this kind of coherently prepared systems and the controlled reversible inhomogeneous broadening technique to propose several quantum information processing applications, such as a protocol for polarization qubit filtering and sieving as well as a tunable polarization beam splitter. Moreover, we show that, by imposing a spatial variation of the atomic coherence phase, an effcient quantum memory for the incident polarization qubit can be also implemented in \Lambda-type three-level systems.