Influence of drying temperature on coconut-fibers.

The use of natural fibers in cementitious composites has been gaining prominence in engineering. The natural lignocellulosic fibers (NLFs) used in these composites have advantages such as reduced density, reduced fragmentation and concrete cracking, thus improving flexural performance and durability. Coconut-fiber is one of those natural fibers and its use presents technical, ecological, social and economic benefits, as it is improperly disposed of, representing a large waste of natural resources, in addition to causing environmental pollution.. Thus, composites reinforced with natural fibers are promising materials for the construction industry, as in addition to meeting the sustainability of buildings, there will also be a reduction in urban solid waste generated and gains for structures with the use of environmentally friendly materials that meet to active efforts and with greater durability. This work aims to evaluate the tensile behavior of green coconut-fibers subjected to different drying temperatures through chemical, thermal (TG/DSC), morphological, visual and mechanical analysis. Drying temperatures of 70 °C, 100 °C and 130 °C were analyzed and the results indicated that the drying temperature at 70 °C was satisfactory, providing fiber-reinforced composites with good tensile strength, combined with good ductility.

In Situ and Operando Characterizations of Metal Halide Perovskite and Solar Cells: Insights from Lab-Sized Devices to Upscaling Processes.

The performance and stability of metal halide perovskite solar cells strongly depend on precursor materials and deposition methods adopted during the perovskite layer preparation. There are often a number of different formation pathways available when preparing perovskite films. Since the precise pathway and intermediary mechanisms affect the resulting properties of the cells, in situ studies have been conducted to unravel the mechanisms involved in the formation and evolution of perovskite phases. These studies contributed to the development of procedures to improve the structural, morphological, and optoelectronic properties of the films and to move beyond spin-coating, with the use of scalable techniques. To explore the performance and degradation of devices, operando studies have been conducted on solar cells subjected to normal operating conditions, or stressed with humidity, high temperatures, and light radiation. This review presents an update of studies conducted in situ using a wide range of structural, imaging, and spectroscopic techniques, involving the formation/degradation of halide perovskites. Operando studies are also addressed, emphasizing the latest degradation results for perovskite solar cells. These works demonstrate the importance of in situ and operando studies to achieve the level of stability required for scale-up and consequent commercial deployment of these cells.

Sputtering of micro-carbon-silver film (µC-Ag) for endotracheal tubes to mitigate respiratory infections.

Polyurethane (PU) substrates are biocompatible materials widely used to manufacture endotracheal tubes. However, in common with other biomedical materials, they are liable to the formation of microbial films. The occurrence of pneumonia in intubated patients treated at intensive care units often takes the form of ventilator-associated pneumonia (VAP). The issue relates to the translocation of pathogenic microorganisms that colonize the oropharyngeal mucosa, dental plaque, stomach, and sinuses. New protective materials can provide a more effective therapeutic approach to mitigating bacterial films. This work concerns microcrystalline carbon film containing dispersed silver nanoparticles (µC-Ag) deposited on PU substrates using a physical vapor deposition sputtering process. For the first time, carbon paper was used to produce a carbon target with holes exposing a silver disk positioned under the carbon paper, forming a single target for use in the sputtering system. The silver nanoparticles were well distributed in the carbon film. The adherence characteristics of the µC-Ag film were evaluated using a tape test technique, and electron dispersive x-ray mapping was performed to analyze the residual particles after the tape test. The microbicidal effect of the thin film was also investigated using speciesS. aureus, a pathogenic microorganism responsible for most infections of the lower respiratory tract involving VAP and ventilator-associated tracheobronchitis (VAT). The results demonstrated that µC-Ag films on PU substrates are promising materials for mitigating pathogenic microorganisms on endotracheal tubes.

Tiny spots to light the future: advances in synthesis, properties, and application of perovskite nanocrystals in solar cells.

Perovskites are in the hotspot of material science and technology. Outstanding properties have been discovered, fundamental mechanisms of defect formation and degradation elucidated, and applications in a wide variety of optoelectronic devices demonstrated. Advances through adjusting the bulk-perovskite composition, as well as the integration of layered and nanostructured perovskites in the devices, allowed improvement in performance and stability. Recently, efforts have been devoted to investigating the effects of quantum confinement in perovskite nanocrystals (PNCs) aiming to fabricate optoelectronic devices based solely on these nanoparticles. In general, the applications are focused on light-emitting diodes, especially because of the high color purity and high fluorescence quantum yield obtained in PNCs. Likewise, they present important characteristics featured for photovoltaic applications, highlighting the possibility of stabilizing photoactive phases that are unstable in their bulk analog, the fine control of the bandgap through size change, low defect density, and compatibility with large-scale deposition techniques. Despite the progress made in the last years towards the improvement in the performance and stability of PNCs-based solar cells, their efficiency is still much lower than that obtained with bulk perovskite, and discussions about upscaling of this technology are scarce. In light of this, we address in this review recent routes towards efficiency improvement and the up-scaling of PNC solar cells, emphasizing synthesis management and strategies for solar cell fabrication.

Sensitivity profile of blood culture isolates in a clinical analysis laboratory, Fortaleza, CE / Perfil de sensibilidade de isolados de hemocultura em um laboratório de análises clínicas, Fortaleza, CE / Perfil de sensibilidad de hemocultivos aislados en un laboratorio de análisis clínicos, Fortaleza, CE

Background and objectives: bacteremia is defined from the presence of bacteria in the bloodstream. Its clinical importance is associated with the high morbidity and mortality rate in the world. In severe cases, it can culminate in sepsis, with a constant increase in cases in Brazil. Therefore, this study aims to assess the main bacterial isolates in blood cultures and a possible change in their sensitivity profiles in a clinical analysis laboratory in Fortaleza, Ceará. Methods: an epidemiological, descriptive, retrospective study was carried out, with a quantitative approach of positive blood cultures, seeking to assess the main isolated microorganisms and their sensitivity profiles. The data used were obtained from the laboratory system through the EpiCenter→ software, from January 2019 to December 2020. Statistical analysis was performed using the Graphpad 7.0 software. Results: 840 microorganisms were identified from blood cultures, and the main ones were E. coli, K. pneumoniae, P. aeruginosa, S. epidermidis, S. aureus and S. haemolyticus. Some isolates show a change in the sensitivity profile, such as K. pneumoniae and P. aeruginosa, showing an increase in sensitivity to carbapenems and cephalosporins, while S. epidermidis showed a decrease in sensitivity to minocycline in the comparison between years 2019 and 2020.Conclusion: clinical isolates from blood cultures showed a change in the sensitivity profile between 2019 and 2020, taking into account that, for K. pneumoniae, P. aeruginosa, this change resulted in an increase in sensitivity, with an increase in resistance in S. epidermidis isolates.(AU)

Justificativa e objetivos: bacteremia é definida a partir da presença de bactérias na corrente sanguínea. Sua importância clínica está associada à alta taxa de morbidade e mortalidade no mundo. Nos casos graves, pode culminar em sepse, com constante aumento dos casos no Brasil. Portanto, o presente estudo tem como objetivo avaliar os principais isolados bacterianos em hemoculturas e uma possível alteração nos seus perfis de sensibilidade em um laboratório de análises clínicas de Fortaleza, Ceará. Métodos: foi realizado um estudo epidemiológico, descritivo, retrospectivo, com abordagem quantitativa de hemoculturas positivas, buscando avaliar os principais microrganismos isolados e seus perfis de sensibilidades. Os dados utilizados foram obtidos a partir do sistema laboratorial através do software EpiCenter→, referente ao período de janeiro de 2019 a dezembro de 2020. A análise estatística foi realizada pelo software Graphpad 7.0. Resultados: foram identificados 840 microrganismos a partir das hemoculturas, sendo os principais E. coli, K. pneumoniae, P. aeruginosa, S. epidermidis, S. aureus e S. haemolyticus. Alguns isolados apresentam uma alteração no perfil de sensibilidade, como K. pneumoniae e P. aeruginosa, apresentando um aumento na sensibilidade frente aos carbapenêmicos e as cefalosporinas, enquanto o S. epidermidis apresentou uma diminuição na sensibilidade frente à minociclina na comparação entre os anos de 2019 e 2020. Conclusão: os isolados clínicos de hemocultura apresentaram uma alteração no perfil de sensibilidade entre 2019 e 2020, levando em consideração que, para K. pneumoniae e P. aeruginosa, essa alteração resultou no aumento na sensibilidade, com aumento na resistência nos isolados de S. epidermidis.(AU)

Justificación y objetivos: la bacteriemia se define por la presencia de bacterias en el torrente sanguíneo. Su importancia clínica está asociada con la alta tasa de morbimortalidad en el mundo. En casos severos, puede culminar en sepsis, con un aumento constante de casos en Brasil. Por tanto, este estudio tiene como objetivo evaluar los principales aislados bacterianos en hemocultivos y un posible cambio en sus perfiles de sensibilidad en un laboratorio de análisis clínicos en Fortaleza, Ceará. Métodos: se realizó un estudio epidemiológico, descriptivo, retrospectivo, con abordaje cuantitativo de hemocultivos positivos, buscando evaluar los principales microorganismos aislados y sus perfiles de sensibilidad. Los datos utilizados se obtuvieron del sistema de laboratorio a través del software EpiCenter→, para el período de enero de 2019 a diciembre de 2020. El análisis estadístico se realizó mediante el software Graphpad 7.0. Resultados: se identificaron 840 microorganismos a partir de hemocultivos, siendo los principales E. coli, K. pneumoniae, P. aeruginosa, S. epidermidis, S. aureus y S. haemolyticus. Algunos aislados muestran un cambio en el perfil de sensibilidad, como K.pneumoniae y P. aeruginosa, mostrando un aumento en la sensibilidad a los carbapenémicos y cefalosporinas, mientras que S. epidermidis mostró una disminución en la sensibilidad a la minociclina, en la comparación entre los años de 2019 y 2020. Conclusiones: los aislados clínicos de hemocultivos mostraron un cambio en el perfil de sensibilidad entre 2019 y 2020, teniendo en cuenta que para K. pneumoniae, P. aeruginosa, este cambio resultó en un aumento de la sensibilidad, con un aumento de la resistencia en los aislados de S. epidermidis

Resistance of Common Bean Genotypes to the Broad Mite, Polyphagotarsonemus latus (Banks, 1904) (Acari: Tarsonemidae): Offspring Development and Biochemical Basis.

The broad mite (BM) Polyphagotarsonemus latus is a pest of great prominence for several crops, including the common bean (Phaseolus vulgaris). The objective of this study was to select resistant genotypes and to determine chemicals associated with resistance. In the first experiment, BM incidence was assessed for 36 genotypes in a greenhouse study. A group of 10 genotypes was selected according to the development of BM populations. Mite populations and phytometric and biochemical variables were then determined to study eventual differential genotypic responses to mite infestation. Lower numbers of mite mobile forms (larvae + adults) were found on Verdão, Negrão and Carioca Original genotypes. The magnitude of differences reached 5.4 times more BM in the IAC Alvorada than the Verdão genotype. Plant yields were reduced for the genotypes TAA Bola Cheia, IPR Sabiá, IPR Uirapuru, IAC Alvorada and Carioca Original when plants were infested with BM. The yields for LP 13833, BRS Esteio, Negrão 11, Verdão and MD 1133 were similar between infested and non-infested genotypes, indicating tolerance. Verdão and Negrão 11, besides the tolerance, exhibited low offspring development, indicating antibiosis and/or antixenosis. Higher phenolic compound levels were found in the Verdão genotype. Increased contents of catalase and peroxidase were detected for Negrão 11 genotype when infested with BM. This work allowed the detection of common bean genotypes that express resistance and tolerance to BM. These genotypes can be used in places with a history of BM infestation, or used in breeding programs to incorporate these characteristics in other genotypes.

Interactions of Ozone-Functionalized Activated Charcoal with SARS-Cov-2 Proteases Using Molecular Docking and Dynamics.

The high contamination by the SARS-Cov-2 virus has led to the search for ways to minimize contagion. Masks are used as part of a strategy of measures to suppress transmission and save lives. However, they are not sufficient to provide an adequate level of protection against COVID-19. Activated charcoal has an efficient antibacterial action, adsorption and low cost. Here, the interaction between two molecules of activated carbon was analyzed, interacting with two structures of the SARS-Cov-2, through docking and molecular dynamics using the platforms Autodock Vina 4.2.6, Gaussian 09 and Amber 16. As a result, the complexes from ozone-functionalized coal to viral structures happen mainly through hydrophobic interactions at the binding site of each receptor. The values of the mean square deviations of the two systems formed by ligands/receptors and showed better stability. The results of Gibbs free energy showed a better interaction between proteins and functionalized charcoal, with △Gtotal values of -48.530 and -38.882 kcal/mol. Thus, the set formed by combinations of proteins with functionalized activated carbon tends to more efficiently adsorb the protein components of the coronavirus to the pores of the activated carbon with ozone during filtration.

Mineral Content, Antioxidant Activity and Essential Oil of Allophylus edulis (A. St.-Hil., A. Juss. & Cambess.) Radlk. Leaves: Plant from South American Biodiversity.

Allophylus edulis (A. St.-Hil., A. Juss. & Cambess.) Radlk. (Sapindaceae) is an edible plant from the South American biodiversity that is a potential source of bioactive compounds. The mineral content and antioxidant activity of Allophylus edulis leaves were investigated, as well as the composition and the antioxidant activity of the essential oil. The mineral content was determined by ICP - OES and the antioxidant assays were assessed by ABTS, DPPH and FRAP. The essential oil was obtained by hydrodistillation and analyzed by GC/MS. Calcium, potassium, phosphorus, sulfur, and magnesium were the main minerals found in A. edulis leaves. Of the toxic metals that were present, a low level of aluminum was detected. The essential oil of A. edulis has (E)-nerolidol as major compound and both, the leaves, and the essential oil isolated from the leaves have antioxidant potential. These findings could provide a framework for developing new food and non-food products with A. edulis leaves.

Tailored organosolv banana peels lignins: Improved thermal, antioxidant and antimicrobial performances by controlling process parameters.

There is a growing environmental concern in the world for replacing the traditional petroleum-based products. The aim of this work was to evaluate the structure - property relationship of banana peel lignins (BPLs) as antioxidant and antimicrobial agents by controlling the parameters of organosolv process. The milled banana peel was hydrolyzed using an aqueous acetic acid solution (70, 80 and 90% v/v) and 2.0% v/v HCl at 110 °C for 1, 2 and 3 h. BPLs were characterized by FTIR, 1H NMR, 1H13C HSQC, 31P NMR, GPC and TGA. The antioxidant capacity of BPLs was evaluated by DPPH, ABTS and H2O2 assays, comparing their performance with that of ascorbic and gallic acid. The antimicrobial activity of BPLs was evaluated against E. coli. The reaction time and acetic acid/water ratio had significant effects on the yield and purity of BPLs. The composition of organosolv solution also affected their total amount of hydroxyls (0.71-0.82 mmol g-1), Mw (2759-3954 g mol-1), Tonset (232-254 °C), antioxidant and antimicrobial activities. It can be concluded that the control of organosolv parameters can be a useful tool for tuning the structural features of lignins and to maximize their performance.

Localization of light induced in ordered colloidal suspensions: powerful sensing tools.

We study the light-matter coupling by Raman scattering in colloidal suspensions composed by core-shell TiO2@Silica (Rutile@Silica) nanoparticles suspended in ethanol and water solutions. Strong enhancement of the Raman signal per particle is observed as [TiO2@Silica] is increased above a threshold, being stronger in ethanol suspensions. Moreover, above this [TiO2@Silica] threshold, the optical transmittance of the ethanol suspension starts to be considerably lower than in water, despite scattering strength being higher in water. These results are attributed to localization of light induced by strong correlation in the scatterers' position as a consequence of the long-range Coulomb interaction between the TiO2@Silica nanoparticles. Light diffraction in TiO2@Silica suspensions (water and ethanol) shows strong correlation in the scatterers' position (structure seemingly cubic), being stronger in ethanol than in water (longer-range Coulomb interaction). As a result, we demonstrate in these colloidal suspensions for the first time, to our knowledge, strongly enhanced light-matter coupling through correlation-induced localization with klT much higher than unity and in an ordered colloidal-photonic structure. This strong enhancement of light-matter coupling by localization of light opens an avenue for manufacturing powerful sensing tools.

Phytotoxic Neocassane Diterpenes from Eragrostis plana.

Five new neocassane-like diterpenes (1-5) were isolated from the roots of Eragrostis plana. Their structures were elucidated by spectroscopic data, and the absolute configurations of the representative compounds neocassa-12(17),15-dien-3-one (2) and neocassa-12(13),15-diene-3,14-dione (5) were assigned by vibrational circular dichroism. The phytotoxic activity of compounds 3, 4, and 5 was evaluated against the germination and growth of Ipomoea grandifolia and Euphorbia heterophylla. Compound 4 exhibited the most potent activity for growth variables, resulting in the smallest radicle length of I. grandifolia and in the smallest aerial part length of E. heterophylla. Compound 5 reduced the germination speed index more effectively than the herbicide glyphosate (Roundup).

Comunicação pública do Ministério da Saúde no Facebook: uma análise das campanhas contra o Aedes aegypti no 'verão do Zika' / Public communication of the Brazilian Ministry of Health in Facebook: A study of the campaigns against the Aedes aegypti during the 'summer of the Zika' / Comunicación pública del Ministerio de Salud brasileño en el Facebook: un análisis de las campañas contra el Aedes aegypti en el 'verano del Zika'

O objetivo deste artigo é analisar as campanhas de comunicação promovidas, no Facebook, pelo Ministério da Saúde contra o mosquito Aedes aegypti. A intenção é identificar quais conteúdos são promovidos pelo Ministério tendo em vista, por um lado, a comunicação de interesse público (associada a políticas de saúde e a valores democráticos, como transparência e participação) e, por outro, as políticas de imagem de instituições e indivíduos, voltadas para auferir vantagens político-eleitorais. O corpus compreende as publicações veiculadas no período que ficou conhecido como o verão do Zika ­ mais exatamente, entre janeiro e abril de 2016. Por meio de investigação quantitativa e qualitativa, verificou-se que há ênfase na abordagem informacionista (nomeadamente, materiais sobre prevenção) e na difusão de serviços. Constatou-se, ademais, que, recorrentemente, publicações de interesse público trazem elementos de políticas de imagem, o que indica a instrumentalização política da comunicação de Estado na área de saúde.

This article analyzes how the Brazilian Ministry of Health uses Facebook to promote communication campaigns against the Aedes aegypti mosquito. We aim to identify what kind of content the Ministry endorses considering, on the one hand, public interest communication (this one is associated with health policy and with democratic values such as transparency and participation), and, on the other hand, the political marketing, in other words, the construction of personal and institutional images and their dissemination to obtain political and electoral profits. The corpus includes Facebook posts published over the period known as the summer of Zika ­ more precisely, between January and April 2016. By using quantitative and qualitative research, we found out that there is an emphasis on the informational approach (especially, online content linked to prevention) and on the dissemination of services. Moreover, the results indicate that the public interest communication posts recurrently bring elements of personal and institutional images, which suggests a political instrumentalization of state communication in the health area.

Este artículo analiza las campañas de comunicación promovidas por el Ministerio de Salud brasileño, en su página en Facebook, contra el mosquito Aedes aegypti. La intención es identificar los contenidos promovidos por el Ministerio, teniendo en cuenta, por un lado, la comunicación de interés público (relacionada a políticas de salud e a principios democráticos como transparencia y participación) y, por otro lado, la construcción de la imagen política de instituciones y personas (con el objetivo de provechos políticos y electorales). El corpus comprende las publicaciones en el período conocido como el verano del Zika ­ de manera más precisa, entre enero y abril de 2016. A través de una investigación cuantitativa y cualitativa, se ha comprobado que el énfasis de las publicaciones es en la información (contenidos sobre prevención) y en la difusión de los servicios. Nosotros también hemos constatado que las publicaciones de interés público usan con frecuencia elementos de construcción de la imagen política. Esto indica la instrumentación política de la comunicación del Estado en el área de salud.

Componentes químicos del aceite esencial de Ocotea paranaensis (Lauraceae) y sus propiedades antioxidantes, anticancer y antimicrobianas / Chemical constituents of Ocotea paranaensis (Lauraceae) essential oil and their antioxidant, anticancer and antimicrobial properties

La composición química del aceite esencial obtenido de las ramas de Ocotea paranaensis se estudió por cromatografía de gases/espectrometría de masas (CG/MS). Se identificaron veintisiete compuestos, que comprenden el 94,82% de los componentes totales. El aceite se caracterizó por una concentración relativamente alta de sesquiterpenos (62,96%), sesquiterpenos oxigenados (33,33%) y diterpeno (3,70%). En cuanto a los compuestos principales, se destacaron Z-nerolidol (19,16%), germacreno D (12,92%) y α-bulnesene (8,47%), que correspondieron al 40,55% de las sustancias encontradas. El aceite esencial analizado de Ocotea paranaensis tiene una buena acción reductora de fosfomolibdeno y es moderadamente tóxico para la Artemia salina (LC50 = 147,91 µg/mL). Mostró potencial hemolítico y actividad moderada contra Staphylococcus aureus (concentración inhibitoria mínima MIC = 250 µg/mL) y Pseudomonas aeruginosa (MIC = 500 µg/mL). No se observaron resultados satisfactorios de citotoxicidad en el linaje H460 y HeLa.

The chemical composition of the essential oil obtained from the branches of Ocotea paranaensis was studied by gas chromatography/mass spectrometry (GC/MS). Twenty-seven compounds, comprising 94.82% of the total components, were identified. The oil showed relatively high concentration of sesquiterpenes (62.96%), oxygenated sesquiterpenes (33.33%), and diterpene (3.70%). Regarding the major compounds, Z-nerolidol (19.16%), germacrene D (12.92%) and α-bulnesene (8.47%) could be highlighted, which corresponded to 40.55% of the substances that were found. The essential oil from Ocotea paranaensis has phosphomolybdenum reducing action and is moderately toxic to the Artemia salina (LC50 = 147.91 µg/mL). It showed haemolytic potential and moderate activity against Staphylococcus aureus, (minimum inhibitory concentration MIC = 250 µg/mL) and Pseudomonas aeruginosa (MIC = 500 µg/mL). No satisfactory cytotoxicity results were observed in lineage H460 and HeLa.

The Thermomechanical Properties of Thermally Evaporated Bismuth Triiodide Thin Films.

Bismuth triiodide (BiI3) has been studied in recent years with the aim of developing lead-free semiconductors for photovoltaics. It has also appeared in X-ray detectors due to the high density of the Bismuth element. This material is attractive as an active layer in solar cells, or may be feasible for conversion into perovskite-like material (MA3Bi2I9), being also suitable for photovoltaic applications. In this study, we report on the thermomechanical properties (stress, hardness, coefficient of thermal expansion, and biaxial and reduced Young's moduli) of BiI3 thin films deposited by thermal evaporation. The stress was determined as a function of temperature, adopting the thermally induced bending technique, which allowed us to extract the coefficient of thermal expansion (31 × 10-6 °C-1) and Young's biaxial modulus (19.6 GPa) for the films. Nanohardness (~0.76 GPa) and a reduced Young's modulus of 27.1 GPa were determined through nanoindentation measurements.

Olfactory response of Mahanarva spectabilis (Hemiptera: Cercopidae) to volatile organic compounds from forage grasses.

Several herbivorous insects utilize plant chemical cues to identify hosts for feeding. The role of smell in host plant detection by Mahanarva spectabilis (Distant) remains largely unknown. In this study, assays were applied to assess M. spectabilis olfactory responses to forage grasses (Pennisetum purpureum cvs. Roxo Botucatu and Pioneiro; Panicum maximum cvs. Makueni and Tanzânia; Hyparrhenia rufa cv. Jaraguá; Melinis minutiflora; Cynodon dactylon cv. Tifton; Brachiaria brizantha cv. Marandú; and Brachiaria decumbens cv. Basilisk). Bioassays were performed using a Y-olfactometer to evaluate the behavior of adult M. spectabilis to forage damaged and undamaged by insects. M. spectabilis preferred volatiles of undamaged Basilisk and Pioneiro. Repellent behavior by M. spectabilis to cospecifics was recorded for plant volatiles from damaged Marandú. The mixture of volatiles from undamaged forage grasses differed from that of forage grasses damaged by insects. Forage grasses showed a greater diversity of compounds after damage, including menthone, eucalyptol and camphor, which are compounds likely to cause loss of attractiveness or repellence. Our results demonstrate that M. spectabilis employs plant chemical cues in its choice of hosts. This fact may contribute to strategies of integrated management against this pest.

Molecular Electronics Including Temperature Effects Based on Dyes Pigments.

In this work we used the Density Functional Theory to study the thermodynamic properties from Brazilein (BZE) and Brazilin (BZI) molecules, main pigments responsible for the red color from Brazil wood. We did a comparison between the two dyes to then know which dye has better resistance to temperature (T ) and external electric field (E) values, aiming their potential to possible applications in solar cells, as excitons trainers. We have found that the BZE molecule becomes less stable after a temperature known as degradation temperature, and therefore enters oxidation state. However, BZE is more stable and more resistant to high temperatures. With respect to the applied external electric field, we find that BZE is more reactive to almost all the applied electric fields, thus more easily converted into energy in the form of electrical work.

Composition, antioxidant properties, and biological activities of the essential oil extracted from Ocotea diospyrifolia (Meisn.) Mez

The article has aimed to characterize the essential oil extracted from Ocotea diospyrifolia (Meisn.) Mez. leaves, in terms of its chemical composition and antioxidant, hemolytic, and phytotoxic potentials, as well as its toxicity against Artemia salina. The major constituents identified by CG-MS were d-elemene, spathulenol, and b-atlantol. When screened for potential biological activities, the essential oil presented low toxicity against Artemia salina, and a capacity of lysing red blood cells. Also, the evaluation of its in vitro antioxidant activity, using the phosphomolybdenum method, showed better results when compared to butylhydroxytoluene (BHT) and rutin. In conclusion, the results obtained showed certain in vitro toxicity, leading to an interesting target for cytotoxicity evaluations of carcinoma cells.

Time-Dependent Density Functional Theory Analysis of Triphenylamine-Functionalized Graphene Doped with Transition Metals for Photocatalytic Hydrogen Production.

The electronic structures and optical properties of triphenylamine-functionalized graphene (G-TPA) doped with transition metals, using water as a solvent, were theoretically investigated to verify the efficiency of photocatalytic hydrogen production with the use of transition metals. This study was performed by Density Functional Theory and Time-dependent Density Functional Theory through Gaussian 09W software, adopting the B3LYP functional for all structures. The 6-31g(d) basis set was used for H, C and N atoms, and the LANL2DZ basis set for transition metals using the Effective Core Potentials method. Two approaches were adopted: (1) using single metallic dopants (Ni, Pd, Fe, Os and Pt) and (2) using combinations of Ni with the other dopants (NiPd, NiPt, NiFe and NiOs). The DOS spectra reveal an increase of accessible states in the valence shell, in addition to a gap decrease for all dopants. This doping also increases the absorption in the visible region of solar radiation where sunlight is most intense (400 nm to 700 nm), with additional absorption peaks. The results lead us to propose the G-TPA structures doped with Ni, Pd, Pt, NiPt or NiPd to be novel catalysts for the conversion of solar energy for photocatalytic hydrogen production, since they improve the absorption of solar energy in the range of interest for solar radiation; and act as reaction centers, reducing the required overpotential for hydrogen production from water.