Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling

<p>Abstract</p> <p>Background</p> <p>With nearly 1,100 species, the fish family Characidae represents more than half of the species of Characiformes, and is a key component of Neotropical freshwater ecosystems. The composition, phylogeny, and classification of Characidae is currently uncertain, despite significant efforts based on analysis of morphological and molecular data. No consensus about the monophyly of this group or its position within the order Characiformes has been reached, challenged by the fact that many key studies to date have non-overlapping taxonomic representation and focus only on subsets of this diversity.</p> <p>Results</p> <p>In the present study we propose a new definition of the family Characidae and a hypothesis of relationships for the Characiformes based on phylogenetic analysis of DNA sequences of two mitochondrial and three nuclear genes (4,680 base pairs). The sequences were obtained from 211 samples representing 166 genera distributed among all 18 recognized families in the order Characiformes, all 14 recognized subfamilies in the Characidae, plus 56 of the genera so far considered <it>incertae sedis </it>in the Characidae. The phylogeny obtained is robust, with most lineages significantly supported by posterior probabilities in Bayesian analysis, and high bootstrap values from maximum likelihood and parsimony analyses.</p> <p>Conclusion</p> <p>A monophyletic assemblage strongly supported in all our phylogenetic analysis is herein defined as the Characidae and includes the characiform species lacking a supraorbital bone and with a derived position of the emergence of the hyoid artery from the anterior ceratohyal. To recognize this and several other monophyletic groups within characiforms we propose changes in the limits of several families to facilitate future studies in the Characiformes and particularly the Characidae. This work presents a new phylogenetic framework for a speciose and morphologically diverse group of freshwater fishes of significant ecological and evolutionary importance across the Neotropics and portions of Africa.</p

STUDY OF AMORPHOUS GERMANIUM-NITROGEN ALLOYS THROUGH X-RAY PHOTOELECTRON AND AUGER ELECTRON SPECTROSCOPIES

In this work, experimentally determined values of electron spectroscopic shifts induced by nitrogen in Ge core levels of substoichiometric amorphous germanium-nitrogen (a-GeN) alloys are discussed and presented. X-ray photoelectron spectroscopy (XPS) and x-ray excited Auger electron spectroscopy (XAES) are employed to study the behavior of the Ge 3d and LMM spectra, respectively, and combined the corresponding XPS and Auger core levels shifts to determine Δα′, the modified Auger parameter shift, which is exempt from problems inherent in the interpretation of XPS and XAES shifts. It is demonstrated how one can use Δα′ to reliably estimate ΔnGe, the change in Ge valence charge in the alloys, and how one can calibrate XPS shifts of Si and Ge based alloys in terms of approximate values of ΔnGe

Mechanical properties of Graphene Nanoribbons

Herein, we investigate the structural, electronic and mechanical properties of zigzag graphene nanoribbons upon the presence of stress applying Density Functional Theory within the GGA-PBE approximation. The uniaxial stress is applied along the periodic direction, allowing a unitary deformation in the range of +/- 0.02%. The mechanical properties show a linear-response within that range while the non-linear dependence is found for higher strain. The most relevant results indicate that Young's modulus is considerable higher than those determined for graphene and carbon nanotubes. The geometrical reconstruction of the C-C bonds at the edges hardness the nanostructure. Electronic structure features are not sensitive to strain in this linear elastic regime, being an additional promise for the using of carbon nanostructures in nano-electronic devices in the near future.Comment: 30 pages. J. Phys.: Condens. Matter (accepted

New cytotoxic neolignans from the cobalt crust fungus

Terana coerulea (Phanerochaetaceae family) is known as the cobalt crust fungus and it is used for its antibiotic properties at the Irati’s Forest (Navarra, Spain). Previous mycochemical investigations reported the isolation of corticins A-C,[1] p-terphenyl neolignans related to the antitumoural telephoric acid.[2] In this job, from powdered dry fungi, six extracts of increasing polarity were obtained and tested for cytotoxicity against four human tumour cell lines and one non-tumour primary cell culture with the sulforhodamine B assay. From the most cytotoxic one, the EtOAc extract, we isolated and identified three p-terphenyl neolignans. One of them was previously described as corticin A by Briggs et al.,[1] whose earlier structure has been revised in this work using one- and two-dimensional NMR, HRMS, positive and negative MS/MS and its peracetyl derivative in comparison with 4’’-deoxy and 4,5-dimethoxy candidusines A.[3] The other two neolignans are new natural products, named corticins D and E. These neolignans were less cytotoxic than the EtOAc extract itself, maybe due to an aerial oxidation and degradation produced when these neolignans, with catechol moieties, are definitively purified.info:eu-repo/semantics/publishedVersio

Delivery of nanogel formulations with antimicrobial peptides for the treatment of mycobacteriosis

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Mycobacterium tuberculosis is the human pathogen that causes Tuberculosis (TB). In 2015, 10.4 million TB cases and 1.8 million deaths were reported, placing this disease alongside HIV/AIDS as the deadliest infectious diseases. Current treatments rely in the administration of a cocktail of four first-line antibiotics during 6 months and, in the worst case scenario, a long-lasting treatment (24 months) with second-line drugs. The overuse or misuse of antimicrobial agents decreases the success of treatments and increases emergence of Multi-drug resistant (MDR) strains. Therefore, the development of new strategies for TB therapy is urgently needed. In this scope, antimicrobial peptides (AMPs) arise as promising candidates for TB treatment since they present high spectrum of antimicrobial activity, high efficacy at low concentrations and low propensity for bacterial resistance. Nevertheless, the low capacity of AMPs to reach the infected site and the use of high concentrations to overcome this problem limits its clinical application - this can be circumvented using a drug delivery system [1]. [...]info:eu-repo/semantics/publishedVersio

Multiplexed vortex beam-based optical tweezers

The design and implementation of a multiplexed spiral phase mask in an experimental optical tweezer setup are presented. This diffractive optical element allows the generation of multiple concentric vortex beams with independent topological charges. The generalization of the phase mask for multiple concentric vortices is also shown. The design for a phase mask of two multiplexed vortices with different topological charges is developed. We experimentally show the transfer of angular momentum to the optically trapped microparticles by enabling orbiting dynamics around the optical axis independently within each vortex. The angular velocity of the confined particles versus the optical power in the focal region is also discussed for different combinations of topological charges

Design of innovative biocompatible cellulose nanostructures for the delivery and sustained release of curcumin

Poor aqueous solubility, stability and bioavailability of interesting bioactive compounds is a challenge in the development of bioactive formulations. Cellulose nanostructures are promising and sustainable carriers with unique features that may be used in enabling delivery strategies. In this work, cellulose nanocrystals (CNC) and cellulose nanofibers were investigated as carriers for the delivery of curcumin, a model liposoluble compound. Nanocellulose modification with the surfactant cetyltrimethylammonium bromide (CTAB), tannic acid and decylamine (TADA), and by TEMPO-mediated oxidation were also tested and compared. The carrier materials were characterized in terms of structural properties and surface charge, while the delivery systems were evaluated for their encapsulation and release properties. The release profile was assessed in conditions that mimic the gastric and intestinal fluids, and cytotoxicity studies were performed in intestinal cells to confirm safe application. Modification with CTAB and TADA resulted in high curcumin encapsulation efficiencies of 90 and 99%, respectively. While no curcumin was released from TADA-modified nanocellulose in simulated gastrointestinal conditions, CNC-CTAB allowed for a curcumin-sustained release of ca. 50% over 8 h. Furthermore, the CNC-CTAB delivery system showed no cytotoxic effects on Caco-2 intestinal cells up to 0.125 g/L, meaning that up to this concentration the system is safe to use. Overall, the use of the delivery systems allowed for the reduction in the cytotoxicity associated with higher curcumin concentrations, highlighting the potential of nanocellulose encapsulation systems.info:eu-repo/semantics/publishedVersio

Bond strength of metallic or ceramic orthodontic brackets to enamel, acrylic, or porcelain surfaces

Bonding strategies within different brackets and dental materials are still a challenge concerning adhesion and dental surface damage. This study compared the shear and tensile bond strength of orthodontic ceramic and metallic brackets to enamel, acrylic, and ceramic surfaces after thermal cycling. Dental surfaces were divided into three groups: enamel, ceramic, and acrylic. Each group received stainless-steel and ceramic brackets. After thermal cycling, specimens were randomly divided into two subgroups considering tensile (TBS) or shear bond strength (SBS) test. After the mechanical testing, scanning electron and optical microscopy were performed, and the adhesive remnant index (ARI) was determined. The two-way ANOVA full factorial design was used to compare TBS, SBS, and ARI on the surface and bracket type (α = 0.05). There were significant differences in TBS, SBS, and ARI values per surface (p p = 0.009) and type of bracket (p = 0.025 and p = 0.001). The highest mean SBS values were recorded for a ceramic bracket bonded to an acrylic surface (8.4 ± 2.3 MPa). For TBS, a ceramic bracket bonded to acrylic showed the worst performance (5.2 ± 1.8 MPa) and the highest values were found on a metallic bracket bonded to enamel. The adhesion of metallic or ceramic brackets is enough for clinical practice although the damage of the enamel surface after debonding is irreversible and harmful for the aesthetic outcome of the teeth.This work was financed by the Conselho Nacional de Desenvolvimento Científico e Tecnológico in the subject of the project PVE/CAPES/CNPq 407035/2013-3, and by FCT (Portugal) on the projects “Development of High Performance Bioinspired Functionally Graded Materials for Oral Rehabilitation”, and NORTE-01-0145-FEDER-000018-HAMaBICo