Valley polarization effects on the localization in graphene Landau levels

Effects of disorder and valley polarization in graphene are investigated in the quantum Hall regime. We find anomalous localization properties for the lowest Landau level (LL), where disorder can induce wavefunction delocalization (instead of localization), both for white-noise and gaussian-correlated disorder. We quantitatively identify the contribution of each sublattice to wavefunction amplitudes. Following the valley (sublattice) polarization of states within LLs for increasing disorder we show: (i) valley mixing in the lowest LL is the main effect behind the observed anomalous localization properties, (ii) the polarization suppression with increasing disorder depends on the localization for the white-noise model, while, (iii) the disorder induces a partial polarization in the higher Landau levels for both disorder models.Comment: 5 pages, 6 figures, extended version, with 2 new figures adde

The Unique Symbiotic System between a Fern and a Cyanobacterium, Azolla-Anabaena azollae: Their Potential as Biofertilizer, Feed, and Remediation

The free-floating aquatic fern Azolla is small and heterosporic, with a worldwide distribution in quiet waters (rivers, dams, creeks, etc.) and is considered an invasive species. This is the only known fern with a permanent symbiotic association with the heterocystic nitrogen-fixing cyanobacterium Anabaena azollae where the cyanobiont is transmitted through the Azolla generations without a de novo infection. The cyanobiont and other bacteria genera inhabit an ovoid cavity in each dorsal lobe of the leaf. The cyanobiont has a high rate of nitrogen fixation and thus this symbiosis was analyzed regarding its biofertilization (incorporated in soil or as manure). In addition, due to the amino acids and protein contents, this fern can also be used as food, and due to the high ability to uptake heavy metals and other pollutants, it can be used as phytoremediator. Since this fern is grown in tropical and subtropical zones where most of the countries have problems regarding the living conditions (health, sanitary, and food, among others) of people, this fern can be a very useful and cheap tool to cope with the severe problems that they face

Resonant tunneling through protected quantum dots at phosphorene edges

We theoretically investigate phosphorene zigzag nanorribons as a platform for constriction engineering. In the presence of a constriction at the upper edge, quantum confinement of edge protected states reveals resonant tunnelling Breit-Wigner transmission peaks, if the upper edge is uncoupled to the lower edge. Coupling between edges in thin constrictions gives rise to Fano-like and anti-resonances in the transmission spectrum of the system.Comment: 8 pages,7 figure

Bioavailability of orange juice (poly)phenols: the impact of short-term cessation of training by male endurance athletes

Background: Physical exercise has been reported to increase the bioavailability of citrus flavanones. Objective: To investigate the bioavailability of orange juice (OJ) (poly)phenols in endurance-trained men before and after cessation of training for 7 days. Design: Ten fit endurance-trained males, with a maximal oxygen consumption of 58.2 ± 5.3 mL/kg/min, followed a low (poly)phenol diet for 2 d before drinking 500 mL of OJ, containing 398 µmol of (poly)phenols of which 330 µmol were flavanones. After the volunteers stopped training for 7 days the feeding study was repeated. Urine samples were collected 12 h pre- and 24 h post-OJ orange consumption. Bioavailability was assessed by the quantitative analysis of urinary flavanone metabolites and (poly)phenol catabolites using HPLC-HR-MS. Results: While training, 0-24 h urinary excretion of flavanone metabolites, mainly hesperetin-3-O-glucuronide, hesperetin-3´-sulfate, naringenin-4´-O-glucuronide, naringenin-7-O-glucuronide, was equivalent to 4.2% of OJ flavanone intake. This increased significantly to 5.2% when OJ was consumed after the volunteers stopped training for 7 days. Overall, this trend, although not significant, was also observed with OJ-derived colonic catabolites which after supplementation in the trained state were excreted in amounts equivalent to 51% of intake compared to 59% after cessation of training. However, urinary excretion of three colonic catabolites of bacterial origin, most notably, 3-(3´-hydroxy-4´-methoxyphenyl)hydracrylic acid, did increase significantly when OJ was consumed post- compared to pre-cessation of training. Data were also obtained on inter-individual variations in flavanone bioavailability. Conclusion: A 7-day cessation of endurance training enhanced, rather than reduced, the bioavailability of OJ flavanones. The biological significance of these differences and, whether or not they extend to the bioavailability of other dietary (poly)phenols, remains to be determined. Hesperetin-3´-O-glucuronide and the colonic microbiota-derived catabolite 3-(3´-hydroxy-4´-methoxyphenyl)hydracrylic acid are key biomarkers of the consumption of hesperetin-O-glycoside-containing OJ and other citrus products

Movement of NO3-N and atrazine through soil columns as affected by lime application

Lime (CaCO3) applied to the soil, to minimize or neutralize the soil pH, can influence the fate and transport of other chemicals in soil. This study was conducted to investigate the effect of lime application on the movement of NO3-N and atrazine through soil columns under saturated and unsaturated conditions

Optimization of Whey Protein-Based Films Incorporating Foeniculum vulgare Mill: Essential Oil

Petroleum-based plastics used in food packaging are not biodegradable. They accumulate in the environment in large amounts, causing a decrease in soil fertility, jeopardizing marine habitats, and causing serious problems to human health. Whey protein has been studied for applications in food packaging, either because of its abundant availability or because it confers transparency, flexibility, and good barrier properties to packaging materials. Taking advantage of whey protein to produce new food packaging materials is a clear example of the so-called circular economy. The present work focuses on optimizing the formulation of whey protein concentrate-based films to enhance their general mechanical properties applying the Box–Behnken experimental design. Foeniculum vulgare Mill. (fennel) essential oil (EO) was incorporated into the optimized films, which were then further characterized. The incorporation of fennel EO in the films leads to a significant increase (p 90%). The results of the bioactive activities of the optimized films showed their ability to be applied as active materials for food packaging to improve the shelf-life of food products and also to prevent foodborne diseases associated with the growth of pathogenic microorganisms.info:eu-repo/semantics/publishedVersio

One decade of evolution of corporate governance practices in Brazil

This study presents the evolution of the quality of corporate governance practices of listed Brazilian companies from 2004 to 2013 by means of a broad corporate governance index (CGI). Results indicate that the quality of corporate governance practices improved, notably after the creation of voluntary membership exchange trading lists that require better corporate governance and disclosure practices. The average CGI score of 5.8 (out of 10.0) in 2013 may be considered low and points to the need for further improvement. Moreover, firms score very low in the ethics & conflicts of interest aspects of the CGI, when compared to its disclosure, board composition & functioning, and shareholders rights components. The very small number of firms that ban loans to related parties and that facilitate participation in the shareholder meetings is a concern. The decrease in the use of control enhancement mechanisms, such as non-voting shares and indirect control structures, was a remarkable achievement. Even so, shareholder agreements are increasingly used as instruments to interfere with director independence and leverage the controlling bloc power.Este estudo apresenta a evolução da qualidade das práticas de governança corporativa de empresas brasileiras negociadas em bolsa entre 2004 e 2013 por meio de um índice abrangente de governança corporativa (CGI). Os resultados indicam que a qualidade das práticas de governança corporativa melhorou, especialmente após a criação dos níveis diferenciados de governança corporativa de adesão voluntária na bolsa, que exigem práticas melhores de governança corporativa e transparência. O CGI médio de 5,8 (em um total de 10) em 2013 pode ser considerado baixo e sugere que pode haver mais espaço para melhoria. Além disso, as empresas pontuam muito baixo nos aspectos de ética & conflito de interesse do CGI, quando comparadas com os componentes sobre transparência, composição & funcionamento do conselho e diretos dos acionistas. O número muito pequeno de empresas que proíbem empréstimos a partes relacionadas e que facilitam a participação nas assembleias de acionistas é uma preocupação. A diminuição de mecanismos de aumento do controle, como as ações sem direito de voto e estruturas indiretas de controle, foi um avanço notável. Mesmo assim, os acordos de acionistas são cada vez mais empregados como instrumentos que interferem com a independência dos conselheiros e aumentam o poder do bloco controlador

Diarrhea-associated biofilm formed by enteroaggregative Escherichia coli and aggregative Citrobacter freundii: a consortium mediated by putative F pili

<p>Abstract</p> <p>Background</p> <p>Enteroaggregative <it>Escherichia coli </it>(EAEC) are enteropathogenic strains identified by the aggregative adhesion (AA) pattern that share the capability to form biofilms. <it>Citrobacter freundii </it>is classically considered as an indigenous intestinal species that is sporadically associated with diarrhea.</p> <p>Results</p> <p>During an epidemiologic study focusing on infantile diarrhea, aggregative <it>C. freundii </it>(EACF) and EAEC strains were concomitantly recovered from a severe case of mucous diarrhea. Thereby, the occurrence of synergic events involving these strains was investigated. Coinfection of HeLa cells with EACF and EAEC strains showed an 8-fold increase in the overall bacterial adhesion compared with single infections (P < 0.001). The synergic effect was mediated by physical interactions among the bacteria and primed in the absence of chemical signaling and without the participation of host cells. Thus, significant increases (2.7-fold on average) in bacterial adhesion were also observed during the formation of mixed biofilms on abiotic surfaces. Bacterial settling assays showed that EAEC strains harboring F-pili genes (<it>traA</it>) were capable of forming bacterial aggregates only in the presence of EACF. Scanning electronic microscopy analyses revealed that bacterial aggregates as well as enhanced biofilms formed by EACF and <it>traA</it>-positive EAEC were mediated by non-bundle forming, flexible pili. Moreover, mixed biofilms formed by EACF and <it>traA</it>-positive EAEC strains were significantly reduced using nonlethal concentration of zinc, a specific inhibitor of F pili. In addition, EAEC strains isolated from diarrheic children frequently produced single biofilms sensitive to zinc.</p> <p>Conclusions</p> <p>Putative F pili expressed by EAEC strains boosted mixed biofilm formation when in the presence of aggregative <it>C. freundii</it>.</p

Breast cancer: biomarkers and biosensors

This study was supported by the Portuguese Foundation for Science and Technology ( under the scope of the strategic funding of UID/BIO/ 04469 2020 unit and BioTecNorte operation (NORTE 01 0145 FEDER 000004 funded by the European Regional Development Fund under the scope of Norte 2020 Programa Operacional Regional do Norte Ana Cláudia Pereira is recipient of fellowships supported by a doctoral advanced training (call NORTE 69 2015 15 funded by the European Social Fund under the scope of Norte 2020 Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio