EDGE-PRESERVING SPECKLE TEXTURE REMOVAL BY INTERFERENCE-BASED SPECKLE FILTERING FOLLOWED BY ANISOTROPIC DIFFUSION

Ultrasonography has an inherent noise pattern, called speckle, which is known to hamper object recognition for both humans and computers. Speckle noise is produced by the mutual interference of a set of scattered wavefronts. Depending on the phase of the wavefronts, the interference may be constructive or destructive, which results in brighter or darker pixels, respectively. We propose a filter that minimizes noise fluctuation while simultaneously preserving local gray level information. It is based on steps to attenuate the destructive and constructive interference present in ultrasound images. This filter, called interference-based speckle filter followed by anisotropic diffusion (ISFAD), was developed to remove speckle texture from B-mode ultrasound images, while preserving the edges and the gray level of the region. The ISFAD performance was compared with 10 other filters. The evaluation was based on their application to images simulated by Field II (developed by Jensen et al.) and the proposed filter presented the greatest structural similarity, 0.95. Functional improvement of the segmentation task was also measured, comparing rates of true positive, false positive and accuracy. Using three different segmentation techniques, ISFAD also presented the best accuracy rate (greater than 90% for structures with well-defined borders). (E-mail: fernando.okara@gmail.com) (C) 2012 World Federation for Ultrasound in Medicine & Biology.

Metal biosorption onto dry biomass of Arthrospira (Spirulina) platensis and Chlorella vulgaris: Multi-metal systems

Binary and ternary systems of Ni2+, Zn2+, and Pb2+ were investigated at initial metal concentrations of 0.5, 1.0 and 2.0 mM as competitive adsorbates using Arthrospira platensis and Chlorella vulgaris as biosorbents. The experimental results were evaluated in terms of equilibrium sorption capacity and metal removal efficiency and fitted to the multi-component Langmuir and Freundlich isotherms. The pseudo second order model of Ho and McKay described well the adsorption kinetics, and the FT-IR spectroscopy confirmed metal binding to both biomasses. Ni2+ and Zn2+ interference on Pb2+ sorption was lower than the contrary, likely due to biosorbent preference to Pb. In general, the higher the total initial metal concentration, the lower the adsorption capacity. The results of this study demonstrated that dry biomass of C. vulgaris behaved as better biosorbent than A. platensis and suggest its use as an effective alternative sorbent for metal removal from wastewater. (C) 2012 Elsevier B.V. All rights reserved.

Selection of Effective Stone Tools by Wild Bearded Capuchin Monkeys

Appreciation of objects` affordances and planning is a hallmark of human technology. Archeological evidence suggests that Pliocene hominins selected raw material for tool making [1, 2]. Stone pounding has been considered a precursor to tool making [3, 4], and tool use by living primates provides insight into the origins of material selection by human ancestors. No study has experimentally investigated selectivity of stone tools in wild animals, although chimpanzees appear to select stones according to properties of different nut species [5, 6]. We recently discovered that wild capuchins with terrestrial habits [7] use hammers to crack open nuts on anvils [8-10]. As for chimpanzees, examination of anvil sites suggests stone selectivity [11], but indirect evidence cannot prove it. Here, we demonstrate that capuchins, which last shared a common ancestor with humans 35 million years ago, faced with stones differing in functional features (friability and weight) choose, transport, and use the effective stone to crack nuts. Moreover, when weight cannot be judged by visual attributes, capuchins act to gain information to guide their selection. Thus, planning actions and intentional selection of tools is within the ken of monkeys and similar to the tool activities of hominins and apes.

Nanoassisted Laser Desorption-Ionization-MS Imaging of Tumors

The ability of nanoassisted laser desorption-ionization mass spectrometry (NALDI-MS) imaging to provide selective chemical monitoring with proper spatial distribution of lipid profiles from tumor tissues after plate imprinting has been tested. NALDI-MS imaging identified and mapped several potential lipid biomarkers in a murine model of melanoma tumor (inoculation of B16/F10 cells). It also confirmed that the in vivo treatment of tumor bearing mice with synthetic supplement containing phosphoethanolamine (PHO-S) promoted an accentuated decrease in relative abundance of the tumor biomarkers. NALDI-MS imaging is a matrix-free LDI protocol based on the selective imprinting of lipids in the NALDI plate followed by the removal of the tissue. It therefore provides good quality and selective chemical images with preservation of spatial distribution and less interference from tissue material. The test case described herein illustrates the potential of chemically selective NALDI-MS imaging for biomarker discovery.

Hybrid heuristic-waterfilling game theory approach in MC-CDMA resource allocation

This paper discusses the power allocation with fixed rate constraint problem in multi-carrier code division multiple access (MC-CDMA) networks, that has been solved through game theoretic perspective by the use of an iterative water-filling algorithm (IWFA). The problem is analyzed under various interference density configurations, and its reliability is studied in terms of solution existence and uniqueness. Moreover, numerical results reveal the approach shortcoming, thus a new method combining swarm intelligence and IWFA is proposed to make practicable the use of game theoretic approaches in realistic MC-CDMA systems scenarios. The contribution of this paper is twofold: (i) provide a complete analysis for the existence and uniqueness of the game solution, from simple to more realist and complex interference scenarios; (ii) propose a hybrid power allocation optimization method combining swarm intelligence, game theory and IWFA. To corroborate the effectiveness of the proposed method, an outage probability analysis in realistic interference scenarios, and a complexity comparison with the classical IWFA are presented. (C) 2011 Elsevier B.V. All rights reserved.

Avaliação clínica e radiográfica do extravasamento da pasta de hidróxido de cálcio em dentes com lesões periapicais

It has been evaluated clinically and radiographically the effect of the extrusion of calcium hydroxide paste in teeth with periapical lesions. Twenty-five patients with teeth showing pulp necrosis and periapical lesions were submitted to endodontic treatment. Dressing calcium hydroxide paste, iodoform and propylene glycol were used. Clinically, the symptoms were evaluated after treatment and, radiographically, the reabsorption of extravasated paste and repair process of the periapical lesion. Only three patients had symptoms severe in the first 24 hours, the paste was completely reabsorbed within 15 days and no interference in the repair process.

The complexity of narrative interferes in the use of conjunctions in children with specific language impairment

PURPOSE: To verify the use of conjunctions in narratives, and to investigate the influence of stimuli's complexity over the type of conjunctions used by children with specific language impairment (SLI) and children with typical language development. METHODS: Participants were 40 children (20 with typical language development and 20 with SLI) with ages between 7 and 10 years, paired by age range. Fifteen stories with increasing of complexity were used to obtain the narratives; stories were classified into mechanical, behavioral and intentional, and each of them was represented by four scenes. Narratives were analyzed according to occurrence and classification of conjunctions. RESULTS: Both groups used more coordinative than subordinate conjunctions, with significant decrease in the use of conjunctions in the discourse of SLI children. The use of conjunctions varied according to the type of narrative: for coordinative conjunctions, both groups differed only between intentional and behavioral narratives, with higher occurrence in behavioral ones; for subordinate conjunctions, typically developing children's performance did not show differences between narratives, while SLI children presented fewer occurrences in intentional narratives, which was different from other narratives. CONCLUSION: Both groups used more coordinative than subordinate conjunctions; however, typically developing children presented more conjunctions than SLI children. The production of children with SLI was influenced by stimulus, since more complex narratives has less use of subordinate conjunctions.

Spatial regimes: dynamics of intentional homicides in the city of Sao Paulo between 2000 and 2008

Objective. To identify the existence of spatial and temporal patterns in the occurrence of intentional homicides in the municipality of Sao Paulo (MSP), Brazil, and to discuss the analytical value of taking such patterns into account when designing studies that address the dynamics and factors associated with the incidence of homicides. Methods. A longitudinal ecological study was conducted, having as units of analysis 13 205 census tracts and the 96 census districts that congregate these sectors in Sao Paulo. All intentional homicides reported in the city between 2000 and 2008 were analyzed. The gross homicide rates per 100 000 population was calculated as well as the global and local Bayesian estimates for each census tract during the study period. To verify the possibility of identifying different patterns of the spatial distribution of homicides, we used BoxMap and Moran's I index. Results. The homicide trends in the city of Sao Paulo in the last decade were not homogeneous and systematic. Instead, seven patterns of spatial distribution were identified; that is, seven spatial regimes for the occurrence of intentional homicides, considering the homicide rates within each census tract as well as the rates in adjacent tracts. These spatial distribution regimes were not contained within the limits of the census tracts and districts. Conclusions. The results show the importance of analyzing the spatial distribution of social phenomena without restriction of political and administrative boundaries.

Isokinetic muscle strength and knee function associated with double femoral pin fixation and fixation with interference screw in anterior cruciate ligament reconstruction

Intensive scheduling in sports requires athletes to resume physical activity shortly after injury. The purpose of this study was to investigate early isokinetic muscle strength and knee function on bone-patellar tendon-bone (BPTB) ACL reconstruction with double femoral pin fixation or interference screw technique. A prospective study was conducted from 2008 to 2009, with 48 athletes who received femoral BPTB fixation with interference screw (n = 26) or double pin (n = 22). Clinical (IKDC objective score and hop test) and isokinetic muscle strength (peak torque (PT), PT/body weight and flexion/extension rate (F/E) in 60 and 240A degrees/s) were analyzed at 6 months of follow-up. Analysis at baseline showed no differences between groups before surgery related to age, gender, associated injury, Tegner or Lysholm score; thus showing that groups were similar. During follow-up, however, there were significant differences between the two groups in some of the isokinetic muscle strength: PT/BW 60A degrees/s (Double Pin = 200% +/- A 13% vs. Interference Screw = 253% +/- A 16%*, *P = 0.01); F/E 60A degrees/s (Double Pin = 89% +/- A 29%* vs. Interference Screw = 74% +/- A 12%, *P = 0.04). No statistical differences between groups were observed on IKDC objective score, hop test and complications. The significant muscle strength outcome of the interference screw group found in this study gives initial evidence that this fixation technique is useful for athletes that may need accelerated rehabilitation. Early return to sports ability signaled by isokinetic muscle strength is of clinical relevance as it is one of the main goals for athletes' rehabilitation. III.

Is shell partitioning between the hermit crabs Pagurus brevidactylus and Pagurus criniticornis explained by interference and/or exploitation competition?

The effect of crab behaviour on shell-use dynamics was analysed, comparing both interference and exploitation behaviours between the hermit crabs Pagurus criniticornis and Pagurus brevidactylus. Although these species exhibited microhabitat separation, with P. criniticornis dominating (100%) in sandy substrates and P. brevidactylus (80%) on rocky shores, they overlapped in the rocky shore/sand interface (P. criniticornis, 53%; P. brevidactylus, 43%). Pagurus criniticornis occupied shells of Cerithium atratum in higher frequencies (84%) than P. brevidactylus (37%), which was hypothesized to be a consequence of competitive interactions combined with their ability to acquire and/or retain this resource. The species P. criniticornis was attracted in larger numbers to simulated gastropod predation events than was P. brevidactylus, which, on the few occasions that it moved before P. criniticornis, tended to be attracted more rapidly. Interspecific shell exchanges between these species were few, suggesting the absence of dominance relationships. The shell-use pattern in this species pair is thus defined by exploitation competition, which is presumed to be intensified in areas of microsympatry. These results differ from other studies, which found that interference competition through interspecific exchanges shapes shell use, indicating that shell partitioning in hermit crabs is dependent on the behaviour of the species involved in the contests.

Regulation of neurogenesis and gliogenesis of retinoic acid-induced P19 embryonal carcinoma cells by P2X2 and P2X7 receptors studied by RNA interference

Embryonic carcinoma cells are widely used models for studying the mechanisms of proliferation and differentiation occurring during early embryogenesis. We have now investigated how down-regulation of P2X2 and P2X7 receptor expression by RNA interference (RNAi) affects neural differentiation and phenotype specification of P19 embryonal carcinoma cells. Wild-type P19 embryonal carcinoma cells or cells stably expressing shRNAs targeting P2X2 or P2X7 receptor expression were induced to differentiate into neurons and glial cells in the presence of retinoic acid. Silencing of P2X2 receptor expression along differentiation promoted cell proliferation and an increase in the percentage of cells expressing glial-specific GFAP, while the presence of beta-3 tubulin-positive cells diminished at the same time. Proliferation induction in the presence of stable anti-P2X2 receptor RNAi points at a mechanism where glial proliferation is favored over growth arrest of progenitor cells which would allow neuronal maturation. Differently from the P2X2 receptor, inhibition of P2X7 receptor expression during neural differentiation of P19 cells resulted in a decrease in cell proliferation and GFAP expression, suggesting the need of functional P2X7 receptors for the progress of gliogenesis. The results obtained in this study indicate the importance of purinergic signaling for cell fate determination during neural differentiation, with P2X2 and P2X7 receptors promoting neurogenesis and gliogenesis, respectively. The shRNAs down-regulating P2X2 or P2X7 receptor gene expression, developed during this work, present useful tools for studying mechanisms of neural differentiation in other stem cell models. (C) 2012 ISDN. Published by Elsevier Ltd. All rights reserved.

RNA interference-mediated knockdown of CD49e (α5 integrin chain) in human thymic epithelial cells modulates the expression of multiple genes and decreases thymocyte adhesion

Abstract Background The thymus is a central lymphoid organ, in which bone marrow-derived T cell precursors undergo a complex process of maturation. Developing thymocytes interact with thymic microenvironment in a defined spatial order. A component of thymic microenvironment, the thymic epithelial cells, is crucial for the maturation of T-lymphocytes through cell-cell contact, cell matrix interactions and secretory of cytokines/chemokines. There is evidence that extracellular matrix molecules play a fundamental role in guiding differentiating thymocytes in both cortical and medullary regions of the thymic lobules. The interaction between the integrin α5β1 (CD49e/CD29; VLA-5) and fibronectin is relevant for thymocyte adhesion and migration within the thymic tissue. Our previous results have shown that adhesion of thymocytes to cultured TEC line is enhanced in the presence of fibronectin, and can be blocked with anti-VLA-5 antibody. Results Herein, we studied the role of CD49e expressed by the human thymic epithelium. For this purpose we knocked down the CD49e by means of RNA interference. This procedure resulted in the modulation of more than 100 genes, some of them coding for other proteins also involved in adhesion of thymocytes; others related to signaling pathways triggered after integrin activation, or even involved in the control of F-actin stress fiber formation. Functionally, we demonstrated that disruption of VLA-5 in human TEC by CD49e-siRNA-induced gene knockdown decreased the ability of TEC to promote thymocyte adhesion. Such a decrease comprised all CD4/CD8-defined thymocyte subsets. Conclusion Conceptually, our findings unravel the complexity of gene regulation, as regards key genes involved in the heterocellular cell adhesion between developing thymocytes and the major component of the thymic microenvironment, an interaction that is a mandatory event for proper intrathymic T cell differentiation.

Expression profiling and cross-species RNA interference (RNAi) of desiccation-induced transcripts in the anhydrobiotic nematode Aphelenchus avenae

Abstract Background Some organisms can survive extreme desiccation by entering a state of suspended animation known as anhydrobiosis. The free-living mycophagous nematode Aphelenchus avenae can be induced to enter anhydrobiosis by pre-exposure to moderate reductions in relative humidity (RH) prior to extreme desiccation. This preconditioning phase is thought to allow modification of the transcriptome by activation of genes required for desiccation tolerance. Results To identify such genes, a panel of expressed sequence tags (ESTs) enriched for sequences upregulated in A. avenae during preconditioning was created. A subset of 30 genes with significant matches in databases, together with a number of apparently novel sequences, were chosen for further study. Several of the recognisable genes are associated with water stress, encoding, for example, two new hydrophilic proteins related to the late embryogenesis abundant (LEA) protein family. Expression studies confirmed EST panel members to be upregulated by evaporative water loss, and the majority of genes was also induced by osmotic stress and cold, but rather fewer by heat. We attempted to use RNA interference (RNAi) to demonstrate the importance of this gene set for anhydrobiosis, but found A. avenae to be recalcitrant with the techniques used. Instead, therefore, we developed a cross-species RNAi procedure using A. avenae sequences in another anhydrobiotic nematode, Panagrolaimus superbus, which is amenable to gene silencing. Of 20 A. avenae ESTs screened, a significant reduction in survival of desiccation in treated P. superbus populations was observed with two sequences, one of which was novel, while the other encoded a glutathione peroxidase. To confirm a role for glutathione peroxidases in anhydrobiosis, RNAi with cognate sequences from P. superbus was performed and was also shown to reduce desiccation tolerance in this species. Conclusions This study has identified and characterised the expression profiles of members of the anhydrobiotic gene set in A. avenae. It also demonstrates the potential of RNAi for the analysis of anhydrobiosis and provides the first genetic data to underline the importance of effective antioxidant systems in metazoan desiccation tolerance.