Abstract Objectives The aim of this study was to evaluate the influence of surfactants 0.2% or 0.1% cetrimide (Cet) or 0.008% benzalkonium chloride (BAK) on 2.5% calcium hypochlorite (Ca(OCl)2), and compare to sodium hypochlorite (NaOCl), regarding the properties of pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity. Material and Methods The pH and free chlorine content were evaluated by digital pHmeter and by titration, respectively. Surface tension was measured by the platinum ring technique with a Du Noüy tensiometer. The solution's contact angle in human dentin surfaces was checked by Drop Shape Analyzer software. Bovine pulps were used for pulp dissolution analysis and the dissolving capacity was expressed by percent weight loss. Antimicrobial activity over Enterococcus faecalis was evaluated by the agar diffusion method. Results Surfactants addition to Ca(OCl)2 and NaOCl did not alter the pH, free chlorine content and pulp dissolution properties. Ca(OCl)2 had the highest surface tension among all tested solutions. When surfactants were added to Ca(OCl)2 and NaOCl, there was a significant reduction of surface tension and contact angle values. The addition of 0.2% or 0.1% Cet enhanced antimicrobial activity of both Ca(OCl)2 and NaOCl. Conclusion Surfactant addition to 2.5% Ca(OCl)2 has shown acceptable outcomes for pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity. Furthermore, the addition of 0.2% Cet showed better results for all tested properties.

A degradação de soluções aquosas de índigo carmim (IC), azul de metileno (MB) e laranja de metilo (MO) assistida pela luz visível foi conseguida sobre a superfície de nanotubos (NTs) de TiO2 impregnados com riboflavina (RF). Soluções aquosas diluídas de RF na presença de RF-NTs TiO2 irradiados com luz UV produziram O2, CO e CO2 como principais produtos gasosos. As mesmas soluções quando irradiadas com luz visível mostraram que o O2 foi o produto principal obtido. Esta geração de O2 in situ com luz visível permite a degradação dos corantes, sem a necessidade de borbulhar ar ou oxigênio no sistema de reação. A degradação fotocatalítica de MO, MB e IC pode ser descrita por um modelo de cinética de pseudo-primeira ordem obtendo ca. 100% de degradação de MB, MO e IC em menos de 3 h de iluminação de luz visível. Os resultados aqui apresentados são altamente promissores em vista da potencial aplicação dos catalisadores RF‑TiO2 NTs preparados com dois compostos ambientalmente corretos na degradação de poluentes utilizando radiação solar.

Visible light-assisted degradation of indigo carmine (IC), methylene blue (MB) and methyl orange (MO) aqueous solutions has been achieved on the surface of TiO2 nanotube (NT) arrays impregnated with riboflavin (RF). Diluted RF water solutions in the presence of RF-TiO2 NTs irradiated with UV light produced O2, CO and CO2 as main gas products. On the contrary, the same solutions irradiated with visible light evolved O2 as a main product. This in situ O2 generation under visible light absorption allows the degradation of the dyes without the necessity to bubble air or oxygen in the reaction system The photocatalytic degradation of MO, MB and IC can be described by a pseudo-first-order kinetic model obtaining ca. 100% degradation of MB, MO and IC in less than 3 h of visible light illumination. The results provided here are highly promising in view of various photocatalytic applications of the prepared RF-TiO2 NTs catalysts by two environmentally friendly compounds in the degradation of pollutants using solar radiation.

Superfícies super-hidrofóbicas com ângulos de contacto maiores ou iguais a 159º foram preparadas utilizando nanopartículas de dióxido de titânio e trimetoxipropil silano (TMPSi) em solventes aquosos ou não aquosos. A superfície super-hidrofóbica preparada em solvente aquoso mostrou uma histerese angular alta. Por outro lado, a superfície super-hidrofóbica preparada em solvente não aquoso teve uma histerese angular baixa e propriedades auto-limpantes. O uso da espectroscopia NEXAFS (Near Edge X-ray Absorption Fine Structure) é demonstrado e justificado no estudo de superfícies super-hidrofóbicas com a ajuda da espectroscopia no infravermelho com transformada de Fourier no modo de refletância total atenuada (FTIR-ATR). O presente estudo realça a importância da heterogeneidade química de uma superfície sobre as propriedades finais de uma superfície super-hidrofóbica. As propriedades autolimpantes de uma superfície super-hidrofóbica somente são obtidas com um completo recobrimento da superfície com TMPSi quando um solvente não aquoso é utilizado. Esse resultado é sustentado por dados detalhados de NEXAFS e FTIR-ATR.

Superhydrophobic surfaces with static water contact angles higher or equal to 159º were fabricated using titanium dioxide nanoparticules and trimethoxypropyl silane (TMPSi) in aqueous or non-aqueous solvents. The superhydrophobic surface fabricated in aqueous solvent showed high contact angle hysteresis. On the other hand, the superhydrophobic surface fabricated in non-aqueous solvent showed low contact angle hysteresis and self-cleaning properties. The application of near edge X-ray absorption fine structure (NEXAFS) spectroscopy in surface analysis of superhydrophobic surface is demonstrated and justified with the help of Fourier transform infrared spectroscopy by attenuated total reflectance (FTIR-ATR). The present work highlights the importance of chemical heterogeneity of the surface on the final properties of a superhydrophobic surface. The self cleaning superhydrophobic surface is obtained only with a complete coverage of the surface with TMPSi in a non-aqueous solvent. This finding is supported by detailed NEXAFS and FTIR-ATR data.

PROBLEM: Reliable demographic data is a central requirement for health planning and management, and for the implementation of adequate interventions. This study addresses the lack of demographic data on mobile pastoral communities in the Sahel. APPROACH: A total of 1081 Arab, Fulani and Gorane women and 2541 children (1336 boys and 1205 girls) were interviewed and registered by a biometric fingerprint scanner in five repeated random transect demographic and health surveys conducted from March 2007 to January 2008 in the Lake Chad region in Chad. LOCAL SETTING: Important determinants for the planning and implementation of household surveys among mobile pastoral communities include: environmental factors; availability of women for interviews; difficulties in defining "own" children; the need for informationeducation-communication campaigns; and informed consent of husbands in typically patriarchal societies. RELEVANT CHANGES: Due to their high mobility, only 5% (56/1081) of registered women were encountered twice. Therefore, it was not possible to establish a demographic and health cohort. LESSONS LEARNT: Prospective demographic and health cohorts are the most accurate method to assess child mortality and other demographic indices. However, their feasibility in a highly mobile pastoral setting remains to be shown. Future interdisciplinary scientific efforts need to target innovative methods, tools and approaches to include marginalized communities in operational health and demographic surveillance systems.

SITUACIÓN: Contar con datos demográficos fiables es un requisito fundamental para la planificación y la gestión sanitarias, así como para la puesta en marcha de las medidas necesarias. El estudio aborda la falta de datos demográficos en las comunidades nómadas de pastores de la región del Sahel. ENFOQUE: Se realizaron entrevistas a un total de 1081 mujeres y de 2541 niños (1336 niños y 1205 niñas) árabes, fulanís y goraneses, y se les incluyó en un registro mediante un lector óptico-biométrico de las huellas dactilares en cinco encuestas demográficas y de salud aleatorias, repetidas y transversales que se realizaron entre marzo de 2007 y enero de 2008 en la región del Lago Chad, en Chad. MARCO REGIONAL: Entre los determinantes más importantes de la planificación y la puesta en marcha de las encuestas domiciliarias en las comunidades nómadas pastoriles se encuentran: los factores medioambientales, la disponibilidad de las mujeres para realizar las entrevistas, las dificultades para definir cuáles son «sus» hijos, la necesidad de desarrollar campañas de información-educacióncomunicación y la obtención de los consentimientos informados de los maridos en las sociedades patriarcales típicas. CAMBIOS IMPORTANTES: Debido a su elevada movilidad, sólo pudimos volver a encontrarnos con el 5% (56:1081) de las mujeres registradas. Por lo tanto, no fue posible establecer una cohorte demográfica y sanitaria. LECCIONES APRENDIDAS: Las cohortes prospectivas de carácter demográfico y sanitario son el método más preciso para evaluar la mortalidad infantil y otros índices demográficos. No obstante, sigue sin demostrarse su viabilidad en grupos de pastores que se desplazan mucho. Los futuros esfuerzos científicos interdisciplinarios deben dirigirse a la obtención de métodos, herramientas y enfoques innovadores que incluyan a las comunidades marginadas en los sistemas operativos de control demográfico y sanitario.

PROBLÈME: La fiabilité des données démographiques constitue un critère majeur, tant pour la planification et la gestion sanitaire que pour la mise en oeuvre d'interventions adéquates. Cette étude s'intéresse au manque de données démographiques concernant les communautés pastorales nomades du Sahel. APPROCHE: Au total, 1 081 femmes et 2 541 enfants (1 336 garçons et 1 205 filles) arabes, foulani et goranes ont été interrogés et enregistrés à l'aide d'un lecteur biométrique d'empreintes digitales, au cours de cinq enquêtes sanitaires et démographiques transversales aléatoires successives, réalisées entre mars 2007 et janvier 2008 dans la région du lac Tchad au Tchad. ENVIRONNEMENT LOCALE: Les facteurs déterminants pour la planification et la mise en oeuvre d'enquêtes auprès des ménages des communautés pastorales nomades comprennent: les facteurs environnementaux, la disponibilité des femmes pour les entretiens, les difficultés à identifier leurs «propres» enfants, le besoin en campagnes d'information, d'éducation et de communication, ainsi que le consentement éclairé des époux au sein de ces sociétés typiquement patriarcales. CHANGEMENTS SIGNIFICATIFS: Du fait de leur grande mobilité, seulement 5% (56/1 081) des femmes enregistrées ont été rencontrées à deux reprises. Il n'a donc pas été possible d'établir de cohorte démographique et sanitaire. LEÇONS TIRÉES: Les cohortes démographiques et sanitaires prospectives constituent la méthode la plus précise pour évaluer la mortalité infantile et les autres indices démographiques. Cependant, leur faisabilité dans un contexte pastoral hautement nomade reste à prouver. Les prochains efforts scientifiques interdisciplinaires devront cibler des méthodes, des outils et des approches novateurs, permettant d'inclure les communautés marginalisées dans des systèmes de surveillance démographique et sanitaire opérationnels.

Um novo método para a fabricação de nanotubos (NTs) de TiO2 organizados e impregnados com nanopartículas (NPs) de ouro foi desenvolvido, e as propriedades estruturais, morfológicas e ópticas dos NTs obtidos foram investigadas. Os arranjos de NTs de TiO2 foram crescidos pela oxidação anódica de Ti metálico utilizando soluções eletrolíticas contendo íons fluoreto e NPs de Au. As estruturas resultantes foram caracterizadas por espectrometria de retroespalhamento Rutherford (RBS), difratometria de raios X com incidência rasante (GIXRD), microscopias eletrônicas de transmissão (TEM) e de varredura (SEM) e espectroscopia UV-Vis. Tanto os arranjos de NTs sem Au quanto os impregnados com Au mostraram atividade fotocatalítica boa e estável na geração de hidrogênio a partir de misturas água/metanol. Os nanotubos de TiO2 contendo Au foram mais ativos na fotogeração de hidrogênio do que os NTs de TiO2 sem Au.

A novel method for the fabrication of TiO2 nanotubes (NTs) impregnated with gold nanoparticles (NPs) is reported. TiO2 NT arrays were grown by anodic oxidation of Ti metal using fluoride electrolytes containing Au NPs. Resulting structures were characterized by Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffractometry (GIXRD), transmission and scanning electron microscopy (SEM and TEM) and UV-Vis spectroscopy. Au-free and Au-impregnated TiO2 NT arrays showed good and stable photocatalytic activity for hydrogen generation from water/methanol solutions. Au-containing TiO2 NTs presented higher hydrogen photogeneration activity than Au-free TiO2 NTs.

Photon stimulated ion desorption (PSID) from condensed carbon dioxide has been studied for photon excitation energies ranging from 93 to 193 eV. PSID studies have been performed at the Brazilian synchrotron light source (LNLS), Campinas, during a multi-bunch operation mode of the storage ring. The results showed that after photon excitation several ions desorbed from the CO2 films: C+ , O+ , CO+ and O2+. PSID experiments showed that ion desorption was enhanced only at the Si resonance excitations. When the thickness of the CO2 was ~ 500 L or higher, almost no desorption yield was observed. The study of the dependence of the relative partial ion yield on the photon excitation showed that the X-ray induced Electron Stimulated Desorption (XESD) mechanism has to be invoked to explain the origin of the desorbed ions in the energy region studied.

With the aim of studying the interaction of fast electrons with solid surfaces we have developed an experimental set-up based on electron stimulated desorption (ESD) coupled to time-of-flight (TOF) mass spectrometry. Poly(methyl methacrylate) and poly(vynil chloride) samples have been irradiated by a pulsed electron beam of 1.2 keV and 0.18 µs FWHM. The results show that H+ is the main ionic species to desorb after electron bombardment. In addition, other ionic fragments were also observed and assigned. These results show the potentiality of this technique in the study of ESD of polymers.