The role of the disorder range and electronic energy in the graphene nanoribbons perfect transmission

Numerical calculations based on the recursive Green's functions method in the tight-binding approximation are performed to calculate the dimensionless conductance $g$ in disordered graphene nanoribbons with Gaussian scatterers. The influence of the transition from short- to long-ranged disorder on $g$ is studied as well as its effects on the formation of a perfectly conducting channel. We also investigate the dependence of electronic energy on the perfectly conducting channel. We propose and calculate a backscattering estimative in order to establish the connection between the perfectly conducting channel (with $g=1$) and the amount of intervalley scattering.Comment: 7 pages, 9 figures. To be published on Phys. Rev.

Existence of solutions for a singular double phase problem involving a ψ\psi-Hilfer Fractional operator via Nehari Manifold

In this present paper, we investigate a new class of singular double phase $p$-Laplacian equation problems with a $\psi$-Hilfer fractional operator combined from a parametric term. Motivated by the fibering method using the Nehari manifold, we discuss the existence of at least two weak solutions to such problems when the parameter is small enough. Before attacking the main contribution, we discuss some results involving the energy functional and the Nehari manifold.Comment: 15 page

Synthesis and characterization of biopolymers functionalized with APTES (3–aminopropyltriethoxysilane) for the adsorption of sunset yellow dye

The biopolymers chitin (CTN) and chitosan (CTS) were functionalized with APTES (3–aminopropyltriethoxysilane) in order to enhance its adsorption potential for sunset yellow dye (SYD). The functionalization was proved by several techniques like FTIR (Fourier transform infrared spectroscopy), XRD (X–ray diffraction), N2 adsorption/desorption isotherms, SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy). The insertion of APTES in the biopolymers has improved the adsorption properties of both, CTN and CTS. The best performance was obtained using CTS functionalized with APTES (CTS–AP), at pH of 4.0, where, more than 99% of the SYD was removed from the solution. Adsorption of SYD on CTS–AP and CTS followed the n–order kinetic model, being that, the use of CTS–AP provided a much faster rate. Freundlich model has better described the isotherms of SYD adsorption on CTS–AP and CTS. An endothermic and physical adsorption was verified. The maximum adsorption capacities were 85 and 95 mg g–1 for CTS and CTS–AP, respectively. The functionalization of CTS with APTES was able to improve the adsorption capacity. However, the main roles of the functionalization was provides a faster adsorption rate, decreasing in 50% the equilibrium time, and, a great recyclability for the adsorbent

SWIMMING BIOPHYSICAL RELEVANT PARAMETERS EXTRACTED FROM VELOCIMETRY AND ACCELEROMETRY

This paper presents different examples of the use of direct velocimetry and accelerometry for the biophysical evaluation and advice of swimmers, assessing relevant parameters for performance enhancement. The described techniques are easy to build and operate, and allow real-and useful-time feedback for practitioners. The velocimetric measurements were based on a cable speedmeter (SwimSensor), and the accelerometric ones using a 3-axial inertial central –WIMU –, incorporating both accelerometers and gyroscopes. Results include swimming intracyclic velocity fluctuations for technical feedback, spectral analysis of the v(t) function to depict bioenergetical anaerobic intensity zones transition and specific fatigue, and breaststroke gliding drag assessment using inverse dynamics

Adsorptive potential of Zn–Al and Mg–Fe layered double hydroxides for the removal of 2–nitrophenol from aqueous solutions

Two layered double hydroxides (LDH) of the type Zn–Al and Mg–Fe were synthesized, characterized and used as adsorbents to uptake 2–nitrophenol (2–NP) from aqueous solutions. XRD, FTIR, SEM, EDS, AFM and N2 adsorption/desorption curves were used to characterize the Zn–Al–LDH and Mg–Fe–LDH. The potential of both layered double hydroxides to adsorb 2–NP was investigated by adsorption kinetics, equilibrium, thermodynamics and consecutive adsorption/desorption cycles. The characterization indicated a high crystallinity degree and a well–organized and lamellar structure, confirming the efficiency of the synthesis. Elovich was the better kinetic model to describe the 2–NP adsorption onto Zn–Al–LDH, while Pseudo–second order was the best for Mg–Fe–LDH. For both LDHs, the adsorption equilibrium followed the Freundlich model. The process was endothermic, being the maximum adsorption capacities of 290 and 165 mg g–1 for Zn–Al–LDH and Mg–Fe–LDH, respectively. LDHs can be applied for five adsorption/desorption cycles with excellent adsorption capacities. It can be concluded that Zn–Al–LDH and Mg–Fe–LDH are promising materials to treat waters and wastewaters containing 2–nitropheno

Identification of New Genes Related to Virulence of Xanthomonas axonopodis Pv. Citri during Citrus Host Interactions

A mutant library of the bacterium Xanthomonas citri subsp. citri strain 306 pathotype A (Xac), the causative agent of most aggressive Asiatic type A citrus canker, was screened regarding altered canker symptoms after inoculations into Citrus sinensis and Citrus limonia host leaves. Twenty-six mutants have shown phenotypic virulence changes and have respectively knocked out gene identified by sequencing. In vivo growth curves were obtained for nine mutants to quantify how the mutations could affect pathogen's adaptability to growth inside and attack host plant infected tissue. Among identified genes in mutated strains, we could find those that until now had not been reported as being involved in Xac adaptation and/or virulence, such as predicted to encode for xylose repressor-like protein (XAC Delta xylR), Fe-S oxidoredutase (XAC Delta aslB), helicase IV (XAC Delta helD), ubiquinol cytochrome c oxidoreductase iron-sulfur subunit (XAC Delta petA), chromosome partitioning protein (XAC Delta parB) and cell division protein FtsB (XAC Delta ftsB), in addition to genes predicted to encode for hypothetical proteins. The new genes found in this study as being relevant to adaptation and virulence, improve the understanding of Xac fitness during citrus plant attack and canker symptoms development.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior-CAPESCNPqFundo de Defesa da Citricultura (FUNDECITRUS)CAPESFUNDECITRUSFAPESPSao Paulo State Univ UNESP, Fac Agr Sci & Vet, Dept Technol, Jaboticabal, SP, BrazilCitriculture Res Ctr Sylvio Moreira IAC Campinas, Campinas, SP, BrazilUniv Fed Ouro Preto, Inst Exact & Biol Sci, Dept Biol Sci, Ouro Preto, MG, BrazilUniv Fed Ouro Preto, Res Ctr Biol Sci NUPEB, Inst Exact & Biol Sci, Dept Biol Sci, Ouro Preto, MG, BrazilSao Paulo State Univ UNESP, Fac Agr Sci & Vet, Plant Hlth Dept, Jaboticabal, SP, BrazilFed Univ Sao Paulo UNIFESP, Dept Biol Sci, Diadema, SP, BrazilFed Univ Sao Paulo UNIFESP, Dept Biol Sci, Diadema, SP, BrazilFAPESP: 04/02006-7Web of Scienc

Effects of a 10 km race on physiological and immunological responses

Introduction: The number of 10 km running races has been increasing in Brazil and the number of finishers almost triplicated in the last decade. However, there is limited amount of data showing the relationship between this event and the immune system response. Aim: Investigate the effects of a 10 km running race on physiological and immunological response in healthy well trained male volunteers. Methods: Fourteen male participants (32,21 ± 10,24 years old, 78,80 ± 9,30 kg) took part in this study. Ratings of perceived exertion (RPE), visual analog scale (VAS), heart rate (HR) and blood samples were taken before, immediately and 24 hours after the race. Lactate, glucose, creatine kinase (CK) and C-reactive protein (CRP), as well as leukocyte number and subpopulation of T cell (CD4+ and CD8+) were analyzed. Results: Participants completed this race in 49,85 ± 7,04 min. There was a significant increase post-race compared to pre-race for HR (67 ± 9 to 159 ± 21 bpm), RPE (6 ± 0 to 15 ± 2) and lactate (3.6 to 6.6 mmol/dL). Glucose levels did not present any significant changes. CK level did not change immediately after the race, but was higher (131,21 ± 62,50 to 286,85 ± 234,35 U/L ) at the 24 h post-race time point. CRP was lower at 24 h (8,37 ± 2,23 to 4,50 ± 2,28 mg/dL). VAS values changed from 0 (before) to 5,64 ± 2,20 (immediately after) to 2,21 ± 2,86 (24 hours). The number of circulating leukocyte (5,83 ± 0,89 to 9,15 ± 1,77 103/µL), neutrophil (2,96 ± 0,49 to 4,34 ± 0,73 103/µL), lymphocyte (2,21 ± 0,57 to 3,92 ± 1,27 103/µL), monocyte (0,46 ± 0,10 to 0,64 ± 0,23 103/µL) and basophil (0,05 ± 0,02 to 0,09 ± 0,03 103/µL) increased significantly immediately after the race, returning to the basal level in 24 h. There was no difference in circulating eosinophils number. The absolute number of CD4+ (828,5 ± 215,8 to 1063,2 ± 235,3 cell/µL) and CD8+ (766,92 ± 347,79 to 1470,30 ± 782,90 cell/µL) also increased immediately after the race returning to basal in 24 h. Significant reduction of the CD4+/CD8+ lymphocyte subpopulation ratio (1,21 ± 0,45 to 0,85 ± 0,33 cell/µL) was observed post-race returning to basal level at 24 h post-race. Results are presented as mean ± SD. (p\u3c0,0001). Conclusion: These results suggest that a 10 km running race is an intense physical activity and induces physiological changes. In addition, intense running provokes a significantly, although transient, modulation of the immune system, specifically of leukocyte sub-population

Extraction techniques and clean-up procedures for the determination of pahs in sediments of the Ceará coast

Extraction and clean-up are essential points in polycyclic aromatic hydrocarbon (PAHs) analysis in a solid matrix. This work compares extraction techniques and clean-up procedures for PAH analysis. PAH levels, their toxicological significance and source were also evaluated in the waters of the Cocó and Ceará rivers. The efficiency of PAH recovery was higher for the soxhlet and ultrasonic techniques. PAH recovery varied from 69.3 to 99.3%. Total PAH concentration (ΣHPA) varied from 720.73 to 2234.76 µg kg-1 (Cocó river) and 96.4 to 1859.21 µg kg-1 (Ceará river). The main PAH sources are pyrolytic processes and the levels were classified as medium so that adverse effects are possible

Effects of disorder range and electronic energy on the perfect transmission in graphene nanoribbons

Numerical calculations based on the recursive Green\u27s function method in the tight-binding approximation are performed to calculate the dimensionless conductance g in disordered graphene nanoribbons with Gaussian scatterers. The influence of the transition from short-to long-ranged disorder on g is studied as well as its effects on the formation of a perfectly conducting channel. We also investigate the dependence of electronic energy on the perfectly conducting channel. We propose and calculate a backscattering estimate in order to establish the connection between the perfectly conducting channel (with g = 1) and the amount of intervalley scattering

Antimicrobial and Photoantimicrobial Activities of Chitosan/CNPPV Nanocomposites

Multidrug-resistant bacteria represent a global health and economic burden that urgently calls for new technologies to combat bacterial antimicrobial resistance. Here, we developed novel nanocomposites (NCPs) based on chitosan that display different degrees of acetylation (DAs), and conjugated polymer cyano-substituted poly(p-phenylene vinylene) (CNPPV) as an alternative approach to inactivate Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. Chitosan's structure was confirmed through FT-Raman spectroscopy. Bactericidal and photobactericidal activities of NCPs were tested under dark and blue-light irradiation conditions, respectively. Hydrodynamic size and aqueous stability were determined by DLS, zeta potential (ZP) and time-domain NMR. TEM micrographs of NCPs were obtained, and their capacity of generating reactive oxygen species (ROS) under blue illumination was also characterized. Meaningful variations on ZP and relaxation time T2 confirmed successful physical attachment of chitosan/CNPPV. All NCPs exhibited a similar and shrunken spherical shape according to TEM. A lower DA is responsible for driving higher bactericidal performance alongside the synergistic effect from CNPPV, lower nanosized distribution profile and higher positive charged surface. ROS production was proportionally found in NCPs with and without CNPPV by decreasing the DA, leading to a remarkable photobactericidal effect under blue-light irradiation. Overall, our findings indicate that chitosan/CNPPV NCPs may constitute a valuable asset for the development of innovative strategies for inactivation and/or photoinactivation of bacteria. Keywords: photoantimicrobial activity; blue-light irradiation; chitosan; CNPPV; nanocomposites; E. coli; S. aureu