1,2-Mannobioside mimic: synthesis, DC-SIGN interaction by NMR and docking, and antiviral activity

The design and preparation of carbohydrate ligands for DC-SIGN is a topic of high interest because of the role played by this C-type lectin in immunity and infection processes. The low chemical stability of carbohydrates against enzymatic hydrolysis by glycosylases has stimulated the search for new alternatives more stable in vivo. Herein, we present a good alternative for a DC-SIGN ligand based on a mannobioside mimic with a higher enzymatic stability than the corresponding disaccharide. NMR and docking studies have been performed to study the interaction of this mimic with DC-SIGN in solution demonstrating that this pseudomannobioside is a good ligand for this lectin. In vitro studies using an infection model with Ebola pseudotyped virus demonstrates that this compound presents an antiviral activity even better than the corresponding disaccharide and could be an interesting ligand to prepare multivalent systems with higher affinities for DC-SIGN with potential biomedical applications.     

A minimally invasive antenna for microwave ablation therapies: design, performances, and experimental assessment

A new coaxial antenna for microwave ablation therapies is proposed. The antenna design includes a miniaturized choke and an arrowhead cap to facilitate antenna insertion into the tissues. Antenna matching and the shape and dimension of the area of ablated tissue (thermal lesion) obtained in ex vivo conditions are evaluated both numerically and experimentally, finding an optimal agreement between numerical and experimental data. Results show that the antenna is well matched, and that it is able to produce a thermal lesion with an average length of 6.5 cm and an average diameter of 4.5 cm in ex vivo bovine liver when irradiates 60 W for 10 min. Finally, the dependence of antenna performances on possible changes in the antenna's structure is investigated, finding an optimal stability with respect to manufacturing tolerances and highlighting the fundamental role played by the antenna's choke.     

Feed restriction and a diet's caloric value: The influence on the aerobic and anaerobic capacity of rats

Background

The influence of feed restriction and different diet's caloric value on the aerobic and anaerobic capacity is unclear in the literature. Thus, the objectives of this study were to determine the possible influences of two diets with different caloric values and the influence of feed restriction on the aerobic (anaerobic threshold: AT) and anaerobic (time to exhaustion: Tlim) variables measured by a lactate minimum test (LM) in rats.

Methods

We used 40 adult Wistar rats. The animals were divided into four groups: ad libitum commercial Purina^? diet (3028.0 Kcal/kg) (ALP), restricted commercial Purina^? diet (RAP), ad libitum semi-purified AIN-93 diet (3802.7 Kcal/kg) (ALD) and restricted semi-purified AIN-93 diet (RAD). The animals performed LM at the end of the experiment, 48 h before euthanasia. Comparisons between groups were performed by analysis of variance (p < 0,05).

Results

At the end of the experiment, the weights of the rats in the groups with the restricted diets were significantly lower than those in the groups with ad libitum diet intakes. In addition, the ALD group had higher amounts of adipose tissue. With respect to energetic substrates, the groups subjected to diet restriction had significantly higher levels of liver and muscle glycogen. There were no differences between the groups with respect to AT; however, the ALD group had lower lactatemia at the AT intensity and higher Tlim than the other groups.

Conclusions

We conclude that dietary restriction induces changes in energetic substrates and that ad libitum intake of a semi-purified AIN-93 diet results in an increase in adipose tissue, likely reducing the density of the animals in water and favouring their performance during the swimming exercises.     

A circuit model of an ultra wideband impulse radar system for breath‐activity monitoring

The aim of this work is to present a circuit model to analyze and design ultra wideband (UWB) radars for the remote monitoring of breath activity. The model includes the impulse signal source, the transceiver antenna, the transmission medium, and the human thorax. First of all, the proposed model has been validated by comparing its responses with those achieved both numerically, with a commercial electromagnetic modeling software, and experimentally, by means of a setup based on an indirect time domain reflectometry system. Then, the model has been used for analyzing the feasibility of a UWB radar operating in the 3–6‐GHz range with an effective isotropic radiated power lower than − 41.3 dBm/MHz, i.e. within the limits issued by the United States Federal Communications Commission for unlicensed UWB imaging systems. The model outlined the possibility of the considered UWB radar of monitoring the breath activity of a subject up to distances of about 10 m in open air. Copyright © 2011 John Wiley & Sons, Ltd.     

Multi-directional modeling of crack pattern in 2D R/C members

A macro-scale approach to R/C modeling is proposed in this paper by formulating a comprehensive model, that describes R/C behavior in the uncracked stage (solid concrete) and in the cracked stage, the latter with either unidirectional cracking (primary cracks) or with bidirectional cracking (primary and secondary cracks) or even multi-directional cracking. The secant stiffness matrix is formulated by means of a direct procedure, based on the assumption that the solid concrete and the reinforcement work in parallel, while the solid concrete between the cracks and the cracks themselves work in series. The resistant mechanisms active at the crack interface are introduced by means of their highly nonlinear laws, that are taken from the literature and are based on well-documented tests. The reliability and accuracy of the proposed model are checked against a few well-documented tests on 2D R/C members failing past the formation of secondary cracks.     

Effect of Cu(II) on the complex between kanamycin A and the bacterial ribosomal A site

The solution structure of kanamycin A interacting with a ribosomal A-site fragment was solved by transferred-NOE techniques and found to agree with the structure of the complex observed in the crystal. Despite the fast exchange conditions found for the interaction, the bound form was identified by NOESY spectroscopy. At 600 MHz, NOE effects are only observed for the RNA-associated antibiotic. Dissociation constants were measured by NMR spectroscopy for two sites of interaction (K(d1)=150+/-40 microM; K(d2)=360+/-50 microM). Furthermore, the effects of the Cu(II) ion on the antibiotic, on the RNA fragment that mimics the bacterial ribosomal A site, and on the complex formed between these two entities were analyzed. The study led to the proposal of a model that localizes the copper ion within the kanamycin-RNA complex.     

A role for α?-adrenergic receptors in extinction of conditioned fear and cocaine conditioned place preference.

Previous work has demonstrated an important role for adrenergic receptors in memory processes in fear and drug conditioning paradigms. Recent studies have also demonstrated alterations in extinction in these paradigms using drug treatments targeting β- and α2-adrenergic receptors, but little is known about the role of α?-adrenergic receptors in extinction. The current study examined whether antagonism of α?-adrenergic receptors would impair the consolidation of extinction in fear and cocaine conditioned place preference paradigms. After contextual fear conditioning, injections of the α?-adrenergic receptor antagonist prazosin (1.0 or 3.0 mg/kg) following nonreinforced context exposures slowed the loss of conditioned freezing over the course of 5 extinction sessions (Experiment 1). After cocaine place conditioning, prazosin had no effect on the rate of extinction over 8 nonreinforced test sessions. Following postextinction reconditioning, however, prazosin-treated mice showed a robust place preference, but vehicle-treated mice did not, suggesting that prazosin reduced the persistent effects of extinction (Experiment 2). These results confirm the involvement of the α?-adrenergic receptor in extinction processes in both appetitive and aversive preparations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solving economic load dispatch problems in power systems using chaotic and Gaussian particle swarm optimization approaches

The objective of the Economic Dispatch Problems (EDPs) of electric power generation is to schedule the committed generating units outputs so as to meet the required load demand at minimum operating cost while satisfying all units and system equality and inequality constraints. Recently, global optimization approaches inspired by swarm intelligence and evolutionary computation approaches have proven to be a potential alternative for the optimization of difficult EDPs. Particle swarm optimization (PSO) is a population-based stochastic algorithm driven by the simulation of a social psychological metaphor instead of the survival of the fittest individual. Inspired by the swarm intelligence and probabilities theories, this work presents the use of combining of PSO, Gaussian probability distribution functions and/or chaotic sequences. In this context, this paper proposes improved PSO approaches for solving EDPs that takes into account nonlinear generator features such as ramp-rate limits and prohibited operating zones in the power system operation. The PSO and its variants are validated for two test systems consisting of 15 and 20 thermal generation units. The proposed combined method outperforms other modern metaheuristic optimization techniques reported in the recent literature in solving for the two constrained EDPs case studies.     

CONJUGATE ANALYSIS OF NATURAL CONVECTIVE DRYING OF BIOLOGICAL MATERIALS

ABSTRACT

This paper presents a numerical analysis of heat and mass transport during natural convective drying of an extruded com meal plate. The conjugate problem of drying and natural convection boundary layer Is modeled. The finite volume technique was used to discretize and solve the highly nonlinear system of coupled differential equations governing the transport inside the plate. The boundary layer solution was obtained by means of a finite difference software package that utilizes Runge-Kutta's 5th order method to solve the inherent transport equations. A methodology for evaluating the heat and mass transfer coefficients during the numerical simulation was developed and successfully implemented. The results showed that there is no analogy between heat and mass transfer coefficients for this type of problem.