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The use of ZnO as a photocatalyst for organics degradation has been reported in the literature, but a divergence of results suggests that surface groups play a critical role in its photoactivity. In this paper, we describe the influence of annealing time on the photoactivity of ZnO particles by analyzing their behavior against molecules with typically high surface adsorption, i.e., methylene blue and rhodamine B. ZnO prepared through the chemical precipitation route at room temperature has been calcined at mild temperatures to gradually eliminate surface –OH groups. Although the increase in annealing time had promoted the crystallite size to increase through the elimination of Zn(OH)2, the particle growth reduced the specific surface area and surface hydroxylation, both of which are critical features concerning photocatalysis. The probing of the main degradation mechanisms evinced that the generation of OH* radicals is the only relevant process for oxidation, which is closely related to the nature of –OH groups. After the complete ZnO crystallization, a balance of morphology, surface area, exposed surface, and surface hydroxylation is necessary to obtain the most efficient materials.

Several methods for the synthesis of anatase TiO2 have been reported in the literature. In particular, the microwave-assisted hydrothermal crystallization of Ti-peroxocomplexes has enabled the phase and morphological control of TiO2 nanoparticles by adjusting the synthesis conditions, such as pH, time and temperature, with significant increase in the reaction rate compared to the conventional sol-gel techniques. In this paper, we uncover the mechanism involved in the formation of anatase TiO2 nanoparticles from the Ti-peroxo complex precursor route. Structural characterizations (XRD, Raman, TEM and XANES) revealed that the Ti-peroxo complex precursor exhibits a titanate-like structure, comprised of bulk NH4+ ions and surface peroxo groups. The NH4+ ions release during hydrothermal treatment is determining on the anatase TiO2 nanoparticle formation, which occurs concomitantly with the decomposition of peroxogroups. UV-induced dye photodegradation tests involving the Ti-peroxo complex precursor and TiO2 nanoparticles showed that the precursor is not able to form hydroxyl radicals that are the main chemical species responsible for the dye photodegradation, despite the presence of peroxo groups at its surface. The results herein highlight the mechanism involved in the formation of anatase TiO2 nanoparticles, which could assist in the development of new synthesis approaches based on Ti-peroxocomplex precursors.

Heteroaggregation of preformed nanocrystals used as building blocks is an interesting approach for the synthesis of heterostructures since it is possible to retain the main surface characteristics of the materials. In this paper, we studied the synthesis of a heterostructure consisting of monoclinic BiVO4 and anatase TiO2 phase for photocatalytic application. The heterostructures were synthesized using the building blocks technique with different TiO2/BiVO4 molar ratios under hydrothermal treatment. The effectiveness of heteroaggregations formation results in more photoactive catalysts due to the possibility of electron transfer between the materials. Methylene Blue (MB) solutions were decolorized under ultraviolet and visible radiation to evaluate the samples? photocatalytic activity. As a result, the as-synthesized samples presented higher photocatalytic efficiency than pristine anatase TiO2 and m-BiVO4 precursors. The increase of the photocatalytic properties is mainly attributed to the separation of the photogenerated charges, which is the central feature of heterostructures formed due to the collision of the particles during hydrothermal treatment. Made available in DSpace on 2022-09-28T19:05:51Z (GMT). No. of bitstreams: 1 P-TiO2-BiVO4-composite-from-preformed-nanoparticles-for.pdf: 17256989 bytes, checksum: e99f761405bd88c16ecdc86456011623 (MD5) Previous issue date: 2022

Resumo Este trabalho versa acerca das percepções das crianças em relação à participação, enquanto direito de se envolver e transformar o contexto socioeducacional, de acordo com seus desejos, intenções e produções. Depois de situar a discussão sobre a participação enquanto direito garantido pelo Estatuto da Criança e do Adolescente e pela Lei da Primeira Infância, apresentamos como esse processo investigativo emergiu na Escola Viva Olho do Tempo, periferia da cidade de João Pessoa – Paraíba. Do ponto de vista metodológico, trata-se de uma pesquisa etnográfica, a partir da observação participante emergida com as crianças enquanto co-pesquisadoras, possibilitando o reconhecimento de seus movimentos emancipatórios ao buscarem garantir e reivindicar o direito à participação, ou não, naquele contexto. Objetivamos refletir a respeito de como as crianças (re)conhecem e tecem suas participações ocupando/participando nos cantos na escola, entre os acordos e conflitos, em suas relações intra e intergeracionais. Ao considerar seus tempos-espaços de afetos e aprendizagens, revelamos como os direitos das crianças são experienciados, entendidos e (re)inventados por elas. Concluímos que é no sentir de suas práticas e experiências, entre as forças e poderes que circundam suas relações, que as crianças aprendem os sentidos de como podem reivindicar, conquistar e (re)criar, em suas alteridades, o direito de participar ou não das práticas no contexto educacional. Abstract This article focuses on children’s perceptions of participation, as their right to get involved and transform the socio-educational context, according to their wishes, intentions and productions. Having placed the discussion on children’s participation as a right guaranteed by the Statute of Children and Adolescents (Estatuto da Criança e do Adolescente) and the Law of Early Childhood, we present how this investigative process emerged at Escola Viva Olho do Tempo, in the outskirts of the city of João Pessoa, state of Paraíba. From a methodological point of view, this is an ethnographic research, based on the participant’s observation that emerged with the children as co-researchers, enabling the recognition of their emancipatory movements when seeking to guarantee and claim the right to participate, or not, in that context. We aim to reflect on how children learn about, recognize and build their participation by occupying /participating in the corners of the school, among agreements and conflicts, in their intra and intergenerational relationships. When considering their time-spaces of affection and learning, we reveal how children’s rights are experienced, understood and (re) invented by them. We conclude that by feeling their practices and experiences, among forces and powers that surround their relationships, children learn how they can claim, conquer and (re)create, in their alterities, the right to participate or not in the practices in the educational context.

Effective heterostructures for photocatalysis need to present good electron-hole mobility among phases, a feature that is only attained with satisfactory interface quality. For very small sizes and with a stable colloidal state, the oriented attachment mechanism can be used to prepare suitable structures by means of a building blocks strategy, whereby preformed nanoparticles are used to control the desired amount of each phase in the heterostructure. Here, we show the success of this strategy for anatase TiO2/rutile SnO2 heterostructures, applying conventional hydrothermal annealing, where successive collisions among particles increase the probability of oriented attachment. The photodegradation of Rhodamine B in water under UV radiation was used as a probe reaction to evaluate formation of the heterostructure, as indicated by an increase in photoactivity. Increased heterostructure photoactivity was related to heterojunction formation and charge separation. The increased lifetimes of the photogenerated charges, due to heterojunction formation, enabled them to reach the oxides surface and promote photocatalytic reactions. The insights presented here may be used in a rationalized synthesis method to obtain heterostructures from preformed nanocrystals.

TiO2 nanoparticles were efficiently doped with Mn applying microwave-assisted synthesis method. Anatase phase was confirmed by XRD pattern, which did not exhibit the peaks associated with MnOx contamination. Raman spectroscopy showed a displacement of up to 5 cm−1 in the O-Ti-O vibrational mode, suggesting that Ti was replaced by Mn. Oxidation state (Mn3+) was confirmed via high-resolution XPS spectrum of Mn 2p energy level. Incorporation of Mn into the TiO2 network resulted in increased surface area (64.6 m2 g−1), average particle size up to 16 nm, and bandgap reduction of up to 43 %. The photocatalytic properties of the materials were investigated through Prozac® degradation and improvement of up to 14 % (Ti-0.73 Mn) and 26 % (Ti-0.38 Mn) was seen on comparing doped TiO2 versus pure TiO2 during photocatalysis. Furthermore, after Prozac® photodegradation, TFMP was identified as the main by-product while MAEB and PPMA (other by-products) were seen to compete with each other in the degradation mechanism. In addition to the quantitative analysis done for Prozac®, TFMP, MAEB, and PPMA, LC MS-Q-TOF analysis was performed, confirming that in the presence of Mn-doped TiO2, specific by-products were formed, probably due to more oxidizing species being present in this reaction system. The present study has shown unprecedented evidence that the application of TiO2 nanoparticles efficiently doped with Mn promotes Prozac® degradation by specific mechanisms.

Photolytic degradation of fluoxetine (FLX), a medicine commonly known as Prozac®, was evaluated by using different photochemical processes. The ultraviolet/microwave (UV/MW) process showed higher efficiency in all the aspects evaluated in this study. The energy consumption was equivalent to 1.94 × 10-4 kW h mg-1 L (UV/MW), while in the UV process the value was 1.20 × 10-2 kW h mg-1 L. The degradation kinetics were applied to the FLX, with rate constant (k) = 0.15 ± 0.01 min-1 and linear correlation coefficient (R2) = 0.980 for UV, and k = 6.15 ± 0.08 min-1 and R2 = 0.998 for UV/MW. The FLX degradation of 99.16% (UV/MW 5 min) and 98.90% (UV 120 min) were observed, evidencing higher efficiency for the first process. The monitoring of transformation products (TPs) through chromatographic analysis enabled the identification of 9 TPs, proving that for the UV/MW process, the hydroxylated structures are verified in high quantity.

This paper describes the deposition of Bi2O3 thin films by spin-coating in a homemade apparatus and their application as photocatalyst in dye photodegradation under UV radiation. For substrate fixation in the spin coating equipment, we developed an alternative method named fit-in method, where the substrate is directlly fixed in a polytetrafluorethylene (PTFE) polymer base used as a sample holder. The Bi2O3 precursor resin was obtained according to the polymeric precursor method and deposited on glass substrates by a dynamic system operating at 4000 RPM, varying the number of added drops (10 or 20), followed by a calcination step to promote oxide crystallization. The thin films were characterized by X-ray diffratometry (XRD), scanning electronic microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and sessile drop method (SDM). The photocatalytic efficiency of Bi2O3 thin films was evaluated by the photodegradation of Rhodamine B (RhB) under UV radiation. The as-obtained Bi2O3 thin films presented high performance in RhB dye removal from aqueous solution and stability during five cycles of reuse, regardless of deposition conditions, which is considered the main feature of a thin film used as a photocatalyst.

Intrusive luxation is a severe form of dental trauma and there is no consensus regarding its management for permanent teeth. A systematic review and meta-analysis was performed to identify the appropriate treatment for teeth with intrusive luxation. The PubMed/MEDLINE, Embase, US Clinical Trials, and ISRCTN Registry electronic databases were used to search for articles in English and unpublished studies without a date limit. Eligible studies evaluated periodontal results (root resorption as the primary outcome; marginal bone defects and/or pulpal changes as secondary outcomes) after spontaneous re-eruption (SRE), orthodontic repositioning (ORP), or surgical repositioning (SRP) for patients with one or more traumatically intruded permanent teeth. Risk ratios with 95% confidence intervals were used to compare treatments. The meta-analysis revealed no significant difference (P0.05) between SRP and SRE for root resorption. For secondary outcomes, SRE was significantly better than SRP and ORP (P0.05). Subgroup analyses showed no significant differences among treatments in teeth with completely formed roots (P0.05) and a better prognosis when SRE was performed in teeth with incompletely formed roots (P0.05). The available evidence does not allow us to conclude on the best treatment for traumatically intruded teeth. More reliable evidence is needed.

Objectives The aim of this study was to estimate the in vitro activity of ceftaroline against clinical Staphylococcus aureus isolates collected during national surveillance in Belgian acute-care hospitals. Ceftaroline-resistant isolates were further investigated for their resistance mechanisms. Methods From October 2013 to March 2014, 155 laboratories of Belgian acute-care hospitals were invited to send to the National Reference Centre-Staphylococcus aureus (Belgium) up to five non-duplicate S. aureus including three MRSA and two MSSA from hospitalized patients. Isolates were analysed by spa typing, SCCmec typing (for MRSA) and PCR for detection of 16S-mecA-nuc and 16S-mecC. MICs of oxacillin, cefoxitin and ceftaroline were determined by the broth microdilution method. The nucleotide sequences of mecA, native pbp and gdpP genes of isolates with reduced susceptibility to ceftaroline were analysed for the presence of mutations responsible for amino acid substitutions. Results Ninety-nine percent of isolates, including MRSA (n = 284) and MSSA (n = 131), were susceptible to ceftaroline. Only four MRSA isolates showed resistance to ceftaroline (MIC = 2 mg/L). These four isolates belonged to lineages CC5 (n = 1), CC22 (n = 2) and CC8 (n = 1). Two isolates (CC22 and CC8) carried mutations in mecA, as well as in other pbp genes. The remaining isolates carried mutations in native pbp genes or in gdpP. Conclusions This is the first Belgian in vitro survey on ceftaroline activity against S. aureus. This antibiotic showed excellent activity against MRSA and MSSA, and only a few MRSA isolates with resistance were found. Reduced susceptibility to ceftaroline seems a complex phenomenon due to the accumulation of mutations in genes involved in β-lactam tolerance.

We used a two-step whole genome sequencing analysis for resolving two concurrent outbreaks in two neonatal services in Belgium, caused by exfoliative toxin A-encoding-gene-positive (eta+) methicillin-susceptible Staphylococcus aureus with an otherwise sporadic spa-type t209 (ST-109). Outbreak A involved 19 neonates and one healthcare worker in a Brussels hospital from May 2011 to October 2013. After a first episode interrupted by decolonization procedures applied over 7 months, the outbreak resumed concomitantly with the onset of outbreak B in a hospital in Asse, comprising 11 neonates and one healthcare worker from mid-2012 to January 2013. Pan-genome multilocus sequence typing, defined on the basis of 42 core and accessory reference genomes, and single-nucleotide polymorphisms mapped on an outbreak-specific de novo assembly were used to compare 28 available outbreak isolates and 19 eta+/spa-type t209 isolates identified by routine or nationwide surveillance. Pan-genome multilocus sequence typing showed that the outbreaks were caused by independent clones not closely related to any of the surveillance isolates. Isolates from only ten cases with overlapping stays in outbreak A, including four pairs of twins, showed no or only a single nucleotide polymorphism variation, indicating limited sequential transmission. Detection of larger genomic variation, even from the start of the outbreak, pointed to sporadic seeding from a pre-existing exogenous source, which persisted throughout the whole course of outbreak A. Whole genome sequencing analysis can provide unique fine-tuned insights into transmission pathways of complex outbreaks even at their inception, which, with timely use, could valuably guide efforts for early source identification.

Strontium titanate nanoparticles have attracted much attention due to their physical and chemical properties, especially as photocatalysts under ultraviolet irradiation. In this paper, we analyze the effect of heating rate during the crystallization process of SrTiO3 nanoparticles in the degradation of organic pollutants. The relationship between structural, morphological and photocatalytic properties of the SrTiO3 nanoparticles was investigated using different techniques. Transmission electron microscopy and N2 adsorption results show that particle size and surface properties are tuned by the heating rate of the SrTiO3 crystallization process. The SrTiO3 nanoparticles showed good photoactivity for the degradation of methylene blue, rhodamine B and methyl orange dyes, driven by a nonselective process. The SrTiO3 sample with the largest particle size exhibited higher photoactivity per unit area, independent of the molecule to be degraded. The results pointed out that the photodegradation of methylene blue dye catalyzed by SrTiO3 is caused by the action of valence band holes (direct pathway), and the indirect mechanism has a negligible effect, i.e. degradation by O2 (-•) and (•) OH radicals attack.

The rapid and unceasing population growth, concomitant with the need for economic development, has led to numerous environmental problems. The most remarkable problems are the release of pesticides in ground water or carbon dioxide in the atmosphere. In this context, nanomaterials are becoming increasingly vital for environmental protection due to their versatile compositions and means of application.

Methicillin-resistant Staphylococcus aureus isolates lacking mec genes ( n = 32), collected from Belgian hospitals, were characterized for their β-lactamase production and the presence of mutations in pbp genes, the pbp4 promoter, and genes involved in penicillin-binding protein 4 overproduction ( gdpP and yjbH ). Twelve isolates were β-lactamase hyperproducers (BHPs), while 12 non-BHP isolates might produce an incomplete GdpP protein. Most isolates showed nucleotide missense mutations in pbp genes. A few isolates also showed mutations in the pbp4 promoter.

Objetivou-se, por meio desta pesquisa, realizar uma análise técnico operacional das máquinas utilizadas na extração florestal mecanizada de eucalipto, em quatro diferentes regionais nos estados do Espírito Santo e Bahia, com a realização de serviços por meio de mão de obra própria e terceirizada, em que estas utilizavam-se de condições climáticas, relevo e maquinários semelhantes. Na pesquisa foram analisados 48 tratores florestais auto carregáveis forwarder, sendo 24 próprios e 24 terceirizados. Avaliou-se a disponibilidade mecânica, eficiência operacional, grau de utilização e produtividadedas máquinas, por meio de coletas em campo e banco de dados dos rendimentos das máquinas. De acordo com os resultados, observou-se que tanto no módulo próprio quanto no terceirizado, as variáveis disponibilidade mecânica, eficiência operacional e grau de utilização, não se diferenciaram quando analisados entre os meses, sendo a diferenciação ocorrida entre as regionais. Os serviços executados por maquinários próprios foram mais eficientes que os terceirizados, com exceção apenas da variável disponibilidade mecânica na regional A. Na análise do volume total extraído por ano, o rendimento com maquinário próprio superou em 1.284.990 m³ o terceirizado. Palavras-chave: análise técnica operacional, baldeio, colheita florestal. OPERATION ANALYSIS OF MECHANICAL EXTRACTION FOREST IN OWN MODULES AND OUTSOURCING ABSTRACT The objective was to realize a technical analysis of operating machinery used in mechanized forest extraction of eucalyptus, in four different regional in the Espirito Santo and Bahia states, with performing services through handheld own and contractors work where they used to climate conditions, relief and similar machinery. In the research were analyzed 48 forwarder, 24 own and 24 contractors. Was evaluated the mechanical availability, operational efficiency, utilization degree and machines production, through field collections and database machines yields. According to the results, it was observed that both the module and its own than contractors, variable mechanical availability, operational efficiency and level of use did not difference when analyzed between months, and differentiation occurred between regionals. The services performed by own machinery were more efficient than contractors, except only the variable mechanical availability in the regional A. When analyzing the total volume extracted per year, income from own machinery climbed by 1.284,990 m³ outsourcing. Keywords: operations technical analyzed, forest extraction, forest harvesting. DOI: http://dx.doi.org/10.14583/2318-7670.v03n03a10

A patient with refractory diffuse lymphoma treated for pulmonary invasive aspergillosis developed a concomitant primary cutaneous mucormycosis. The mucormycete was identified by sequencing as Mucor circinelloides. This case confirms the importance of a rapid pathogen diagnosis in immunocompromised patients and the usefulness of molecular methods for identification of rare fungal species.

One of the primary challenges in obtaining heterostructures is control of the morphology and surface features of the components that are suitable for a specific application. In this sense, the use of preformed nanoparticles as building blocks is interesting. However, to create heterojunctions between preformed nanoparticles, a further calcination step is usually needed that can result in changes in nanoparticle morphology and surface chemistry. Therefore, the main goal of this study was to explore collision-induced heteroaggregation and oriented attachment under hydrothermal conditions to obtain heterostructures from preformed nanoparticles without further thermal treatment or addition of capping agents. We use anatase TiO2 and rutile SnO2 nanoparticles as a model system. A kinetic model based on a diffusion-controlled reaction is adapted to describe the process. For tracking charge migration across the interface and, consequently, heterojunction formation, we employ an indirect method based on the detection of hydroxyl radicals formed over a semiconductor during UV radiation. The rate of hydroxyl radical formation is directly proportional to the photogenerated charge lifetime, which, in turn, depends on the number of heterojunctions formed. The insights presented here suggest the possibility of obtaining the benefits of heterostructures by using nanoparticles with controlled morphology and surface characteristics.

This paper evaluates the photocatalytic and dye adsorption properties of highly crystalline orthorhombic vanadium pentoxide (V2O5) one-dimensional (1D) nanostructures, such as nanowires and nanorods, synthesized by a hydrothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning and transmission electron microscopy (SEM and TEM), thermogravimetry (TGA), zeta potential, Fourier transform infrared spectrometry (FTIR), N2 adsorption isotherms and high-resolution 13C nuclear magnetic resonance (NMR). The dye adsorption capability and photocatalytic properties under visible light were mainly studied by the removal of the methylene blue dye (MB). Despite their low specific surface area (approximately 35 m2 g−1), the nanostructures showed high MB adsorption capabilities of greater than 400 mg g−1. Additionally, due to the band-gap values (approximately 2.6 eV), the nanostructures could be successfully applied to photodegradation under visible light, showing higher photoactivity than commercial V2O5. The MB adsorption mechanism onto V2O5 1D-nanostructures surface can be explained via NMe2+ interaction with the negatively charged surface of the studied samples. The observed combination of adsorbent and photocatalytic properties makes the V2O5 1D-nanostructures a promising material for organic pollutant decontamination, which appears more efficient for cationic species.

This paper reports a facile low temperature hydrothermal process to grow highly porous ZnO nanosheets, self-assembled in rosette-like morphology, over the transparent indium tin oxide (ITO) glass substrate for dye-sensitized solar cell application. The prepared porous nanosheets were examined in detail using several techniques to understand the morphological, structural, compositional, optical and photovoltaic properties. The detailed morphological investigations reveal that the prepared nanosheets are made by the accumulation of small ZnO nanoparticles with typical diameters of 28 ± 3 nm. A systematic growth process to prepare such ZnO nanosheets is also discussed in terms of chemical reactions involved. The prepared nanosheets possess the stoichiometric elemental ratios of Zn and oxygen and exhibiting good crystallinity and wurtzite hexagonal phase along with good optical properties. Furthermore, the prepared ZnO nanosheets on ITO substrates were directly utilized as a photo-anode to fabricate an efficient dye-sensitized solar cell (DSSC), which demonstrated a reasonable light-to-electricity conversion efficiency of ∼3.4% with high short circuit current (JSC) of 9.45 mA cm−2, open circuit voltage (VOC) of 0.654 and fill factor of 0.55. The obtained JSC and the performance of the fabricated DSSC are attributed to the high surface to volume ratio of porous ZnO nanosheets, which delivers the high light harvesting efficiency.

This paper reports the synthesis of monoclinic bismuth vanadate (BiVO4) by the oxidant peroxide method with crystallization under hydrothermal conditions, and its catalytic performance on the photodegradation of pollutants under visible light. The as-synthesized BiVO4 materials were characterized by means of X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and scanning electron microscopy (SEM). Hydrothermal treatment above 80 °C was required to obtain pure monoclinic BiVO4 phase by releasing V5+ ions from vanadium peroxo complexes. With the increase in hydrothermal reaction temperature, the particle size decreased. All BiVO4 samples presented large size and shape distribution and band gap of approximately 2.40 eV. The as-prepared BiVO4 catalysts showed high photoactivity for decomposition of model pollutants, methylene blue (MB) and rhodamine B (RhB) dyes, under exposure to visible light. The photodegradation mechanism was evaluated by adding scavengers, DMSO and KBrO3, which were used to probe ˙OH radical and conduction band (CB) electrons, respectively. It was observed that photodegradation of MB and RhB dyes is caused by the action of ˙OH radicals, and that BiVO4 CB electrons do not have reduction potential sufficiently high to reduce dissolved oxygen to O2−˙. It was proven that the indirect mechanism, i.e. ˙OH radical formation, plays the major role on the BiVO4-assisted photodegradation process.

This work describes the facile aqueous solution based syntheses and detailed characterization of zinc based hydroxide/oxide and zinc hydroxy stannate materials and their efficient utilization as catalyst for the photodegradation of harmful organic dye, i.e. Rhodamine B. The detailed studies revealed that the reaction time and temperature are important parameters by which the crystal phases and morphology of prepared materials can be controlled. Therefore, it was observed that with increasing the reaction time and temperature, a mixed phase of Zn(OH)2 and ZnO and pure ZnO can be prepared. The detailed characterizations showed that zinc hydroxy stannate cubes grow in high density and possess cube shaped morphologies. The detailed photocatalytic experiments revealed that as-synthesized ZnSn(OH)6 cubes possess higher photoactivity compared to the zinc based hydroxide/oxide materials. The stability results indicated no significant deactivation even after four successive re-uses in RhB photodegradation. Furthermore, the rate of ˙OH radical formation during UV irradiation was also tracked to investigate the mechanism of RhB photodegradation. The same trend was also observed on comparing the photoactivity and rate of ˙OH radical formation. Thus, it can be proposed that the mechanism of RhB degradation catalyzed by the as-synthesized materials followed an indirect oxidation of the dye by ˙OH radicals formed over the photocatalyst during UV irradiation, instead of direct electron transfer between dye and photocatalyst because there was no remarkable adsorption of the dye onto the photocatalyst surface.

This paper describes the synthesis of TiO2-SnO2 heterostructures and their application to water decontamination based on the photodegradation of Rhodamine B (RhB). The heterostructures were fabricated through two different routes, a hydrolytic sol gel and the polymeric precursor method, both of which induced the growth of SnO2 on commercial TiO2. The results show that the heterostructures presented higher photoactivity behaviors than commercial TiO2 nanopowders. The achievement of homogeneity during phase formation (i.e., of the SnO2 dispersion over the TiO2 nanoparticles) was a key parameter for obtaining higher photocatalytic activities per unit area. The main degradation mechanism was correlated with the process of OH radical generation, which was related to the concentration and nature of the surface hydroxyl groups. Accordingly, the polymeric precursor method was shown to be more adequate for dispersing higher amounts of SnO2 in comparison with the hydrolytic sol gel method. Additionally, the polymeric precursor method delivered higher proportions of bonded surface hydroxyl groups, which were responsible for radical formation; in contrast, the hydrolytic sol gel method demonstrated the highest amount of adsorbed water.

A photochemical reactor composed of an Hg-MDEL was applied in photodegradation studies of fluoxetine (Prozac®). The reactor exhibited to be an efficient hydroxyl radical generation system, since the O • H quantification studies conducted with coumarin (COU), 4-hydroxycoumarin (4HC) and 7-hydroxycoumarin (7HC) solutions resulted in the kinetics constant of formation of O • H kOH = 3.14 ± 0.18 min−1. When the Hg-MDEL reactor was applied for degradation of Prozac®, the study of variation of the microwave power allowed a significant increase in the rate of degradation of the Prozac®, indicating that the hydroxyl radical formation is optimized through the adjustment of this parameter. An increase in the initial concentration of Prozac from 33 to 134 μmol L−1 resulted in a 21% decrease in the kinetic constant value, the mean kinetic constant was k = 10.64 ± 1.25 min −1 and R 2 = 0.943 ± 0.131. The Prozac® photodegradation studies showed that the application of the pseudo-first-order kinetics should be limited to the time of up to 0.50 min for the respective system, due to the influence exerted by the transformation products. In general, the total removal of Prozac® was 100% for its highest concentration (134 μmol L−1) at the time of 0.75 min. As for the solution of Prozac® 101 μmol L−1, the energy consumption was 6 kW h g−1, achieving a removal of 99%. Finally, the photochemical system presented in this work demonstrates a high efficiency in the formation of hydroxyl radicals, a high degradation rate of organic compounds (Prozac®, COU and 7HC) and low energy consumption.

Despite photocatalytic degradation is studied generally focusing the catalyst, its interaction with the contaminant molecule plays a fundamental role in the efficiency of that process. Then, we proposed a comparative study about the photodegradation of two well-known dyes, with different acidity/basicity - Methylene Blue (MB) and Rhodamine B (RhB), catalyzed by TiO2 nanoparticles, varying both dye and photocatalyst concentrations. The results showed that the amphoteric character of MB molecules, even in a range of concentration of 5.0-10.0 mg L(-1) , did not imply in pH variation in solution. Therefore, it did not affect the colloidal behavior of TiO2 nanoparticles, independent of the relative dye/catalyst concentration. The acid-base character of RhB influenced the resultant pH of the solution, implicating in different colloidal behavior of the nanoparticles and consequently, in different degradation conditions according to dye concentration. As the isoelectric point of TiO2 is between the pH range of the RhB solutions used in this study, from 1.0 to 7.5 mg L(-1) , the resultant pH was the key factor for degradation conditions, from a well dispersed to an agglomerated suspension.

Anodic interference films were grown on stainless steel by an electrochemical process in a 70 g L−1 CrO3+500 g L−1 H2SO4 solution at temperatures of 25–75°C. The aim of this research was to assess the influence of temperature on characteristics of this coating. The morphology of the films was assessed through atomic force microscopy, the chemical composition was assessed by X-ray photoelectron spectroscopy, while the mechanical characteristics were assessed by resistance to abrasion wear and nanohardness. The roughness of the films grown at 25°C is less than that of the other temperatures. No significant difference regarding the porosity of the films was detected. A chromium hydroxide was observed on the top of the oxide layer grown on stainless steel. The steel coloured at 75°C presented a lesser hardness compared to the samples grown at 25, 35 and 55°C. The wear resistance increased as the temperature of the film’s growth rose, which was inversely proportional to the hardness.

OBJECTIVES It is common wisdom that persistent carriage of Staphylococcus aureus is more frequent in young children than in adults. The objectives of this study were to assess the S. aureus temporal carriage pattern among a healthy community of pre-school children, with concomitant description of genotype diversity, toxin-encoding genes and antibiotic resistance. METHODS Among 333 children 3-6 years of age, S. aureus nasopharyngeal carriage was assessed over one school year by culture of three sequential nasopharyngeal aspirates. Identification, methicillin resistance and toxin production profile were determined by PCR. Genotyping was performed by spa sequencing and multilocus sequence typing (MLST). RESULTS Out of 830 samples collected, 286 (34%) yielded S. aureus from 185 carriers (55%). Based on consecutive genotype analysis, only 40/268 (15%) children could be classified as persistent carriers, and the remaining 118 (44%) showed intermittent carriage. spa typing revealed 82 types clustered into 13 spa clonal complexes (CCs). Fourteen strains isolated from 11 (3%) children were methicillin-resistant S. aureus (MRSA), half of these strains belonged to the commonly hospital-associated spa t008-ST8-SCCmec IV. Methicillin-susceptible S. aureus (MSSA) were genotypically more diverse. Toxic shock syndrome toxin and egc1/2 complexes were highly prevalent (24%). Contrastingly, Panton-Valentine leucocidin (PVL) was carried only by three MSSA strains (0.6% of children). Exfoliative toxins were detected in 10 (3.5%) MSSA strains, of which 5 were related to the impetigo clone CC121. CONCLUSIONS Although S. aureus nasopharyngeal carriage was high among healthy pre-school children, persistent carriage seems to be less frequent than previously reported. The prevalence of MRSA carriage was 3%, but was not associated with PVL.

Objectives: To validate and accredit a set of three multiplex endpoint PCR assays, targeting the most important carbapenemase and minor extended-spectrum β-lactamase (ESBL) resistance genes, according to the international ISO 15189 particular requirements for the quality and competence of medical laboratories. Methods: Specific primers targeting ESBLs and carbapenemases were collected from the literature or designed internally. The multiplex PCRs were validated for sensitivity, specificity, intra- and inter-run reproducibility and accuracy by means of external quality control (EQC) using a collection of 137 characterized and referenced isolates. For each multiplex PCR assay, the presence of an extraction control ruled out false-negative results due to PCR inhibition or extraction faults. Amplicons were separated by capillary electrophoresis (QIAxcel system, Qiagen). The protocols and validation files were reviewed in the setting of an external audit conducted by the Belgian organization for accreditation (BELAC). Results: Sensitivity, specificity and reproducibility for each targeted gene were 100%. All isolates from the three EQC panels were correctly identified by each PCR assay (accuracy 100%). The validation files were controlled by BELAC, and the PCR protocols were accepted as accredited according to ISO 15189. Conclusions: Three home-made multiplex PCRs targeting the major carbapenemases and four minor class A ESBL genes encountered in Gram-negative bacteria were accredited according to the ISO 15189 standards. This validation scheme could provide a useful model for laboratories aiming to accredit their own protocols. © The Author 2013. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

Anti-Flavivirus antibodies are highly cross-reactive and may facilitate Zika virus (ZIKV) infection through the antibody-dependent enhancement (ADE) mechanism. We ­demonstrate that dengue-specific antibodies enhance the infection of a primary Brazilian ZIKV isolate in a FcγRII-expressing K562 cell line. In addition, we demonstrate that serum samples from dengue-immune pregnant women enhanced ZIKV infection. These findings highlight the need for epidemiological studies and animal models to further confirm the role of ADE in the development of congenital and neurological complications associated with ZIKV infections.

Since the emergence of Zika virus (ZIKV) in Brazil in 2015, 48 countries and territories in the Americas have confirmed autochthonous cases of disease caused by the virus. ZIKV-associated neurological manifestations and congenital defects make the development of safe and effective antivirals against ZIKV of utmost importance. Here we evaluated the antiviral activity of 6-methylmercaptopurine riboside (6MMPr), a thiopurine nucleoside analogue derived from the prodrug azathioprine, against the epidemic ZIKV strain circulating in Brazil. In all of the assays, an epithelial (Vero) and a human neuronal (SH-SY5Y) cell line were used to evaluate the cytotoxicity and effective concentrations of 6MMPr against ZIKV. Levels of ZIKV-RNA, viral infectious titre and the percentage of infected cells in the presence or absence of 6MMPr were used to determine antiviral efficacy. 6MMPr decreased ZIKV production by >99% in both cell lines in a dose- and time-dependent manner. Interestingly, 6MMPr was 1.6 times less toxic to SH-SY5Y cells compared with Vero cells, presenting a 50% cytotoxic concentrations (CC50) of 460.3 µM and 291 µM, respectively. The selectivity index of 6MMPr for Vero and SH-SY5Y cells was 11.9 and 22.7, respectively, highlighting the safety profile of the drug to neuronal cells. Taken together, these results identify, for the first time, the thiopurine nucleoside analogue 6MMPr as a promising antiviral candidate against ZIKV that warrants further in vivo evaluation.

Resumo A gestão do uso da água no ambiente agrícola é fator decisivo para a construção de métodos produtivos ambientalmente sustentáveis. A fotocatálise é um método promissor para a descontaminação de águas. Este artigo teve como proposta avaliar o potencial fotocatalítico de partículas de ZnO puro e dopado com manganês. Estes materiais foram produzidos pelo método dos precursores poliméricos e caracterizados por difratometria de raios X, adsorção de N2 em baixa temperatura, espectroscopia na região do infravermelho e do ultravioleta e fotoluminescência. Para avaliação da eficiência dos fotocatalisadores obtidos, ensaios de fotodegradação foram realizados utilizando-se o corante azul de metileno sob radiação UVC. As partículas apresentaram-se monofásicas, porém com baixa área superficial específica. A amostra de ZnO com teor de dopagem de 0,25% de Mn apresentou maior eficiência no processo fotocatalítico para a degradação do corante azul de metileno. Esta eficiência foi relacionada com o maior valor de energia de band gap e menor taxa de recombinação eletrônica, o que permite maior formação de radicais de hidroxila, compostos estes responsáveis pela degradação do corante. Abstract The management of water use in the agricultural environment is a key factor to build new environmentally sustainable productive methods. Photocatalysis is a promising method for water decontamination. This research paper aimed to evaluate the photocatalytic potential of pure and Mn-doped ZnO particles. The materials were obtained by the polymeric precursor method, and characterized by X-ray diffraction, N2 adsorption in low temperature, infrared and ultraviolet spectroscopy, and photoluminescence. In order to evaluate ZnO:Mn particles photoefficiency, experiments were carried out by applying the methylene blue dye solution to photodegradation under UVC exposure. The particles had ZnO single-phase, but low specific surface area. The sample ZnO:0.25% Mn presented higher efficiency in the methylene blue photocatalytic degradation test. This efficiency was related to a higher band gap energy value and a lower rate of electron recombination, which allows greater formation of hydroxyl radicals, which are responsible for dye degradation.

Background Viral encephalitis is a common cause of lethal infections in humans, and several different viruses are documented to be responsible. Rocio virus is a flavivirus that causes a severe lethal encephalitis syndrome in humans and also mice, providing an interesting model to study the CNS compartmentalized immune response. Interleukin 33 (IL-33), a member of the IL-1 family, is an immunomodulatory cytokine that is highly expressed in the CNS. However, the role of IL-33 on viral encephalitis remains unclear. Therefore, we aimed to explore how the IL-33/ST2 axis regulates the local immune response during Rocio virus infection. Methods Wild-type (WT), ST2 (ST2−/−), and nitric oxide synthase-deficient mice (iNOS−/−) and Stat6 (Stat6−/−)-deficient mice were infected with different concentrations of the Rocio virus by intraperitoneal route, the cytokine mRNA level in CNS was analyzed by qPCR, and cellular immunophenotyping was performed on infected mice by the flow cytometry of isolated CNS mononuclear cells. Results We have shown that the mRNA expression of IL-33 and ST2 receptors is increased in the CNS of Rocio virus-infected WT mice and that ST2−/− mice showed increased susceptibility to infection. ST2 deficiency was correlated with increased tissue pathology, cellular infiltration, and tumor necrosis factor alpha (TNF-α) and interferon-gamma (IFN-γ) mRNA levels and higher viral load in the CNS, compared with wild-type mice. The increased Th1 cytokine levels released in the CNS acted on infiltrating macrophages, as evidenced by flow cytometry characterization of cellular infiltrates, inducing the expression of iNOS, contributing to brain injury. Moreover, iNOS−/− mice were more resistant to Rocio virus encephalitis, presenting a lower clinical score and reduced mortality rate, despite the increased tissue pathology. Conclusions We provide evidences of a specific role for IL-33 receptor signaling in nitric oxide induction through local IFN-γ modulation, suggesting that nitric oxide overproduction might have an important role in the progression of experimental viral encephalitis. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0628-1) contains supplementary material, which is available to authorized users.

The purpose of this systematic review was to perform a comparative analysis of the use or not of graft material in maxillary sinus lift surgery. Relevant studies published in the last 10 years were identified through a search of the PubMed/MEDLINE, ScienceDirect, and Cochrane Library databases and were assessed against the study inclusion and exclusion criteria. The initial search resulted in 1037 articles. After applying the inclusion and exclusion criteria, 16 articles remained. Four hundred and thirty-six patients were followed up over a postoperative period ranging from 6 months to 11 years. In total, 868 implants were installed in 397 maxillary sinuses. The implant survival rate was 96.00% for surgeries performed without graft material and 99.60% for those in which biomaterial was used, within a follow-up period of 48 to 60 months. In conclusion, maxillary sinus lift surgery, with or without graft material, is a safe procedure with a low complication rate and predictable results.

Objectives: Rapid diagnosis and appropriate empirical antimicrobial therapy before the availability of conventional microbiological results is of pivotal importance for the clinical outcome of ventilator-associated pneumonia (VAP). We evaluated the VAPChip, a novel, closed cartridge molecular tool aiming to identify directly from clinical samples and within a working day the principal bacteria causative of VAP as well as clinically relevant β-lactam resistance genes. Methods: The Real-time Array PCR for Infectious Diseases (RAP-ID) is a novel technology that combines multiplex PCR with real-time microarray detection. The VAPChip is a closed cartridge kit adapted to the RAP-ID instrument that targets 13 key respiratory pathogens causative of VAP and 24 relevant antimicrobial resistance genes that mediate resistance to β-lactam agents, including extended-spectrum cephalosporins and carbapenems. Analytical validation of the VAPChip was carried out blindly on a collection of 292 genotypically characterized bacterial reference and clinical isolates, including 225 isolates selected on the basis of their species identification and antimicrobial resistance profiles and 67 bacterial isolates belonging to the oropharyngeal flora not targeted by the array. Results: The limit of detection of the assay lies between 10 and 100 genome copies/PCR and the dynamic range is five orders of magnitude permitting at least semi-quantitative reporting of the results. Sensitivity, specificity and negative and positive predictive values ranged from 95.8% to 100% for species identification and detection of resistance genes. Conclusions: VAPChip is a novel diagnostic tool able to identify resistant bacterial isolates by RAP-ID technology. The results of this analytical validation have to be confirmed on clinical specimens. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.