An efficient method for genomic DNA extraction from different molluscs species

The selection of a DNA extraction method is a critical step when subsequent analysis depends on the DNA quality and quantity. Unlike mammals, for which several capable DNA extraction methods have been developed, for molluscs the availability of optimized genomic DNA extraction protocols is clearly insufficient. Several aspects such as animal physiology, the type (e.g., adductor muscle or gills) or quantity of tissue, can explain the lack of efficiency (quality and yield) in molluscs genomic DNA extraction procedure. In an attempt to overcome these aspects, this work describes an efficient method for molluscs genomic DNA extraction that was tested in several species from different orders: Veneridae, Ostreidae, Anomiidae, Cardiidae (Bivalvia) and Muricidae (Gastropoda), with different weight sample tissues. The isolated DNA was of high molecular weight with high yield and purity, even with reduced quantities of tissue. Moreover, the genomic DNA isolated, demonstrated to be suitable for several downstream molecular techniques, such as PCR sequencing among others.     

Simultaneous Classification of Teas According to Their Varieties and Geographical Origins by Using NIR Spectroscopy and SPA-LDA

Due to the human health benefits already scientifically proven, tea (Camellia sinensis) has been widely studied in the literature. Several studies report the classification of the variety or geographical origin of teas, separately. Thus, this paper has proposed a methodology for simultaneous classification of tea samples according to their varieties (green or black) and geographical origins (Brazil, Argentina, or Sri Lanka). For this purpose, near-infrared (NIR) spectroscopy and three differing supervised pattern recognition techniques, namely SIMCA (soft independent modeling of class analogy), PLS-DA (partial least squares-discriminant analysis), and SPA-LDA (successive projections algorithm associated with linear discriminant analysis) have been used. Despite having good results, both full-spectrum PLS-DA and SIMCA were not able to achieve 100 % classification accuracy, regardless of the significance level for the F test in the case of the SIMCA model. On the other hand, the resulting SPA-LDA model successfully classified all studied samples into five differing tea classes (Argentinean green tea; Brazilian green tea; Argentinean black tea; Brazilian black tea; and Sri Lankan black tea) using 12 wave numbers alone.     

Primary neurogenesis in Xenopus embryos regulated by a homologue of the Drosophila neurogenic gene Delta

X-Delta-1, a Xenopus homologue of the Drosophila Delta gene, is expressed in the early embryonic nervous system in scattered cells that appear to be the prospective primary neurons. Ectopic X-Delta-1 activity inhibits production of primary neurons and interference with endogenous X-Delta-1 activity results in overproduction of primary neurons. These results indicate that the X-Delta-1 protein mediates lateral inhibition delivered by prospective neurons to adjacent cells, and that commitment to a neural fate in vertebrates is regulated by Delta-Notch signalling as in Drosophila.     

Operational failure experience of fault-tolerant digital control systems

Fault-tolerant digital control systems (F-T DCSs) can theoretically achieve extremely high reliability, i.e. high mean time between failures (MTBFs). However, in actual applications theoretical MTBFs are idealized goals, and even the more modest goals can only be achieved with great effort at the design stage (particularly software design) and with excellence in operation/maintenance throughout the life of the system. This paper discusses the reliability performance of F-T DCSs, including a presentation of actual failure experience from 20 different computer system installations. Particular emphasis is given to identifying major contributors to system unreliability and comparing different types of F-T DCS architectures.     

Characterization of MAO‐Modified Silicas for Ethylene Polymerization

A series of methylaluminoxane (MAO)‐modified PQ and EP 12 silicas, calcined at 110, 250, and 450°C, were prepared. The resulting MAO‐modified supports were characterized by a set of complementary techniques: Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy‐energy dispersive X‐ray spectroscopy (SEM‐EDX), small angle X‐ray scattering (SAXS), and thermal gravimetric analysis (TGA). The Al/Si ratios of the MAO‐modified PQ and EP12 silicas were in the ranges of 0.19–0.27 wt % and 0.17–0.30 wt %, respectively. MAO‐modified silicas were used in the polymerization of ethylene using an Et₂IndZrCl₂ catalyst. The MAO‐modified PQ silica showed higher activity in comparison to the MAO‐modified EP12. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4568–4575, 2013     

Optimized orthonormal wavelet filters with improved frequency separation

This paper proposes an optimization-based method to design orthonormal wavelet filters with improved frequency separation. The proposed approach adopts a parameterization of orthogonal filter banks which ensures that the resulting wavelets have at least two vanishing moments. The filter parameters are adjusted by a numerical optimization algorithm in order to minimize a cost function associated to cut-off sharpness. In comparison with standard orthonormal filters, the proposed method is shown to provide better trade-off between frequency selectivity and time resolution. For illustration, the optimized filters are employed in an application example involving the use of a wavelet-packet system identification scheme. As a result, the identification errors are smaller than those obtained by using a non-optimized filter with the same length.     

Evaluating two implementations of the component responsible for decoding video and audio in the Brazilian digital TV middleware

The project Ginga Code Development Network (GingaCDN) was created to implement a reference version of Ginga, the Brazilian Digital Television System (SBTVD) middleware, supporting the declarative GingaNCL and the procedural GingaJ environments in the same middleware. To reach that, a common core is being implemented, named Ginga Common Core (GingaCC). One of the main components of the GingaCC is the one responsible to decode audio and video streams, called Media Processing. In this work, two Media Processing implementations using libVLC and Xine graphical libraries are investigated. Performance tests and results of both Media Processing implementations running in two different desktop architectures are discussed.     

A routing protocol suitable for backhaul access in wireless mesh networks

This work proposes the Wireless-mesh-network Proactive Routing (WPR) protocol for wireless mesh networks, which are typically employed to provide backhaul access. WPR computes routes based on link states and, unlike current routing protocols, it uses two algorithms to improve communications in wireless mesh networks taking advantage of traffic concentration on links close to the network gateways. WPR introduces a controlled-flooding algorithm to reduce routing control overhead by considering the network topology similar to a tree. The main goal is to improve overall efficiency by saving network resources and avoiding network bottlenecks. In addition, WPR avoids redundant messages by selecting a subset of one-hop neighbors, the AMPR (Adapted MultiPoint Relay), needed to reach all two-hop ones. We first analyze the proposed algorithms compared with the algorithms used by OLSR for the same tasks in terms of running time, optimality, and number of routing messages. Results show that the algorithms proposed by WPR are more efficient than the algorithms used by OLSR in running time and number of routing messages. In addition, we also perform simulations to evaluate the performance of WPR. Results reveal that the aggregated throughput of WPR outperforms OLSR by up to 27% using a combination of web and backbone internal traffic despite our design assumption of traffic convergence toward gateways.     

Fipronil (active ingredient of acaricide Frontline®) acting on the mice thyroid

Fipronil, active ingredient of Frontline® acaricide, is a phenyl‐pyrazolic derivative, and its efficacy in the elimination of several plagues, even in lower concentrations, has already been demonstrated; however, its effect on nontarget organisms has not been thoroughly explained. In this sense, the present study had the objective to evaluate the effects of different doses of fipronil in mice and determine its cytotoxic potential and possible compromises on nontarget organisms in artificial conditions. The results showed that animals exposed to fipronil presented significant alterations in the thyroidean tissue with evident follicular disorganization, decreased in the size of most follicles culminating with the rupture of smaller follicles and still with posterior fusion in a big and irregular “follicle” filled with colloid. The present study also revealed that the action of fipronil not only causes disorganization in the thyroidean tissue but alsoalters the chemical composition of the colloid itself (prehormone), modifying its proteic basis, which was confirmed by histochemical test for protein detection, making it clear that, in thyroids exposed to fipronil, the colloid was weakly positive or even negative for the presence of proteins in its constitution. Microsc. Res. Tech. 2011. © 2011 Wiley Periodicals, Inc.