Peptide-based interactions with calnexin target misassembled membrane proteins into endoplasmic reticulum-derived multilamellar bodies.

Oligomeric assembly of neurotransmitter transporters is a prerequisite for their export from the endoplasmic reticulum (ER) and their subsequent delivery to the neuronal synapse. We previously identified mutations, e.g., in the gamma-aminobutyric acid (GABA) transporter-1 (GAT1), which disrupted assembly and caused retention of the transporter in the ER. Using one representative mutant, GAT1-E101D, we showed here that ER retention was due to association of the transporter with the ER chaperone calnexin: interaction with calnexin led to accumulation of GAT1 in concentric bodies corresponding to previously described multilamellar ER-derived structures. The transmembrane domain of calnexin was necessary and sufficient to direct the protein into these concentric bodies. Both yellow fluorescent protein-tagged versions of wild-type GAT1 and of the GAT1-E101D mutant remained in disperse (i.e., non-aggregated) form in these concentric bodies, because fluorescence recovered rapidly (t(1/2) approximately 500 ms) upon photobleaching. Fluorescence energy resonance transfer microscopy was employed to visualize a tight interaction of GAT1-E101D with calnexin. Recognition by calnexin occurred largely in a glycan-independent manner and, at least in part, at the level of the transmembrane domain. Our findings are consistent with a model in which the transmembrane segment of calnexin participates in chaperoning the inter- and intramolecular arrangement of hydrophobic segment in oligomeric proteins.

Local relevancy evaluation in the accreditation bodies for engineering master's programs

Accreditation models in the international context mainly consider the evaluation of learning outcomes and the ability of programs (or higher education institutions) to achieve the educational objectives stated in their mission. However, it is not clear if these objectives and therefore their outcomes satisfy real national and regional needs, a critical point in engineering master's programs, especially in developing countries. The aim of this paper is to study the importance of the local relevancy evaluation of these programs and to analyze the main models of quality assurance and accreditation bodies of USA, Europe and Latin America, in order to ascertain whether the relevancy is evaluated or not. After a literature review, we found that in a free-market economic context and international education, the accreditation of master’s programs follows an international accreditation model, and doesn´t take in account in most cases criteria and indicators for local relevancy. It concludes that it is necessary both, international accreditation to ensure the effectiveness of the program (achievement of learning outcomes) and the national accreditation through which it could ensure local relevancy of programs, for which we are giving some indicators.

Aeroelastic characteristics of slender wing/bodies with freeplay non-linearities

This article presents a time domain approach to the flutter analysis of a missile-type wing/body configuration with concentrated structural non-linearities. The missile wing is considered fully movable and its rotation angle contains the structural freeplay-type non-linearity. Although a general formulation for flexible configurations is developed, only two rigid degrees of freedom are taken into account for the results: pitching of the whole wing/body configuration and wing rotation angle around its hinge. An unsteady aerodynamic model based on the slender-body approach is used to calculate aerodynamic generalized forces. Limit-cycle oscillations and chaotic motion below the flutter speed are observed in this study.

Boundary element formulation for elastoplastic analysis of axisymmetric bodies

The complete formulation of B.E.M. applied to the analysis of axisymmetric bodies acting in the plastic range is presented in this paper. The concept of derivative of a singular integral given by Mikhlin has been used in order to calculate the stresses in internal points. Also a semianalytical approach is proposed to compute the matrix coefficients, presenting the way in which it can be done and the results obtained.

Hysteresis phenomena in transverse galloping of triangular cross-section bodies

Transverse galloping is a type of aeroelastic instability characterised by large amplitude, low frequency oscillation of a structure in the direction normal to the mean wind direction. It normally appears in bodies with small stiffness and structural damping, provided the incident flow velocity is high enough. In the simplest approach transverse galloping can be considered as a one-degree-of-freedom oscillator subjected to aerodynamic forces, which in turn can be described by using a quasi-steady description. In this frame it has been demonstrated that hysteresis phenomena in transverse galloping is related to the existence of inflection points in the curve giving the dependence with the angle of attack of the aerodynamic coefficient normal to the incident flow. Aiming at experimentally checking such a relationship between these inflection points and hysteresis, wind tunnel experiments have been conducted. Experiments have been restricted to isosceles triangular cross-section bodies, whose galloping behaviour is well documented. Experimental results show that, according to theoretical predictions, hysteresis takes place at the angles of attack where there are inflection points in the lift coefficient curve, provided that the body is prone to gallop at these angles of attack.

MOIRA-PLUS use in decision making on the long-term management of contaminated freshwater bodies and catchments

In the mid-long-term after a nuclear accident, the contamination of drinking water sources, fish and other aquatic foodstuffs, irrigation supplies and people?s exposure during recreational activities may create considerable public concern, even though dose assessment may in certain situations indicate lesser importance than for other sources, as clearly experienced in the aftermath of past accidents. In such circumstances there are a number of available countermeasure options, ranging from specific chemical treatment of lakes to bans on fish ingestion or on the use of water for crop irrigation. The potential actions can be broadly grouped into four main categories, chemical, biological, physical and social. In some cases a combination of actions may be the optimal strategy and a decision support system (DSS) like MOIRA-PLUS can be of great help to optimise a decision. A further option is of course not to take any remedial actions, although this may also have significant socio-economic repercussions which should be adequately evaluated. MOIRA-PLUS is designed to allow for a reliable assessment of the long-term evolution of the radiological situation and of feasible alternative rehabilitation strategies, including an objective evaluation of their social, economic and ecological impacts in a rational and comprehensive manner. MOIRA-PLUS also features a decision analysis methodology, making use of multi-attribute analysis, which can take into account the preferences and needs of different types of stakeholders. The main functions and elements of the system are described summarily. Also the conclusions from end-user?s experiences with the system are discussed, including exercises involving the organizations responsible for emergency management and the affected services, as well as different local and regional stakeholders. MOIRAPLUS has proven to be a mature system, user friendly and relatively easy to set up. It can help to better decisionmaking by enabling a realistic evaluation of the complete impacts of possible recovery strategies. Also, the interaction with stakeholders has allowed identifying improvements of the system that have been recently implemented.

Far wake structure in rarefied plasma flows past charged bodies

The asymptotic structure of the far-wake behind a charged body in a rarefied plasma flow is investigated under the assumption of small ion-to-electron temperature ratio and of flow speed hypersonic with respect to the ions but not with respect to the electrons. It is found that waves are excited even if the flow is subacoustic (flow velocity less than the ion-acoustic speed). For both superacoustic and subacoustic velocities a steep wave front develops separating the weakly perturbed, quasineutral plasma ahead, from the region behind where ion waves appear. Near the axis a trailing front develops;the region between this and the axis is quasineutral for superacoustic speeds. The decay laws in all of these regions, the self-similar structure of the fronts and the general character of the waves are determined.The damping of the waves and special flow detail for bodies large and small compared with the Debye length are discussed. A nonlinear analysis of the leading wave front in superacoustic flow is carried out. A hyperacoustic equivalence principle is presented.

Learning from the living bodies: New principles and techniques for photonic sensing

Signal processing in any living being is much more complex than the one performed in artificial systems. Cortex architecture, although only partly known, gives some useful ideas to be employed in sensing technology. To analyze some of these structures is the objective of this paper. Among the points to be analyzed are the parallel transfer of information, the similarity of the different systems and the massive amount of data analyzed by physical techniques. As an example of these concepts, the possibility to transmit images in a parallel way will be reported.

Sensitivity analysis to assess the influence of the inertial properties of railway vehicle bodies on the vehicle’s dynamic behaviour

A sensitivity analysis has been performed to assess the influence of the inertial properties of railway vehicles on their dynamic behaviour. To do this, 216 dynamic simulations were performed modifying, one at a time, the masses, moments of inertia and heights of the centre of gravity of the carbody, the bogie and the wheelset. Three values were assigned to each parameter, corresponding to the percentiles 10, 50 and 90 of a data set stored in a database of railway vehicles. After processing the results of these simulations, the analyzed parameters were sorted by increasing influence. It was also found which of these parameters could be estimated with a lesser degree of accuracy for future simulations without appreciably affecting the simulation results. In general terms, it was concluded that the most sensitive inertial properties are the mass and the vertical moment of inertia, and the least sensitive ones the longitudinal and lateral moments of inertia.