The influence of alizarin and fluorescein on the photoactivity of Ni,Pt and Ru-doped TiO2 layers

The doping with different metal ions and sensitization with organic compounds are two well known methods used to improve the photoactivity of TiO₂. In this respect, the metallic ions-doped TiO₂ samples were prepared by embedding Ni, Pt and Ru ions into TiO₂ crystalline network and then, each sample was sensitized with alizarin and fluorescein dyes. The qualitative evaluation of prepared TiO₂-based materials was made by: UV–vis spectroscopy, spectrofluorimetry, FT/IR spectroscopy and microscopy, X-ray diffraction and N₂ physisorption measurements. The optoelectronic properties investigated by UV–vis spectroscopy show that the optical response of Ni-doped TiO₂ layer shifts to visible. The X-ray spectra do not show peaks of nickel, platinum and ruthenium oxide crystals or pure metals. The FT/IR spectra proved the presence of dye molecules adsorbed on titania nanoparticles surface. These results demonstrated that the studied dopants and dyes have potential to promote modified TiO₂-based materials as good candidates to be used in photolectrocatalytic processes.     

Microbial Enhanced Oil Recovery (MEOR)

Microbial enhanced oil recovery (MEOR) represents the use of microorganisms to extract the remaining oil from reservoirs. This technique has the potential to be cost-efficient in the extraction of oil remained trapped in capillary pores of the formation rock or in areas not swept by the classical or modern enhanced oil recovery (EOR) methods, such as combustion, steams, miscible displacement, caustic surfactant-polymers flooding, etc. Thus, MEOR was developed as an alternative method for the secondary and tertiary extraction of oil from reservoirs, since after the petroleum crises in 1973, the EOR methods became less profitable. Starting even from the pioneering stage of MEOR (1950s) studies were run on three broad areas, namely, injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and metabolites production by microorganisms and their effects.     

Sunscreens' photochemical behaviour: in vivo evaluation by the stripping method

This study shows the influence of a water-in-oil emulsion and an oil-in-water emulsion on the photochemical behaviour of four sunscreen preparations containing various amounts of three UV filters: octyl methoxycinnamate, butyl methoxydibenzoylmethane, and 4-methylbenzylidene camphor. With the stripping method in vivo, skin-product interactions were evaluated after topical application and ultra-violet exposure. Evaluations were also made under the same operating conditions as in determining sun protection factor in vivo. Results showed that each sunscreen preparation has a particular photochemical behaviour related to filter mixture and emulsion type. When developing a sunscreen preparation the choice of the emulsion type and filters is relevant for achieving optimum efficacy and spectral stability.     

Transport mechanism analysis of non-equilibrium charge carrier in heterojunctions with GaS-CdTe:Mn thin films

The current-voltage characteristics in the temperature range 170 ÷ 305 K at the direct polarization of GaS-CdTe:Mn heterojunction were studied. The tunneling process of carriers determines the electrical current through the junction. The ratio of the diffusion coefficient and surface recombination velocity in the CdTe:Mn film from the interface of junction was determined from the spectral characteristics of short circuit current and absorption. The non-equilibrium carriers generated in the CdTe:Mn film at the interface of heterojunction at the temperature of 293 K recombine through two recombination levels. At low temperatures (T < 170 K) the concentration of carriers decreases and only one recombination level appears with the short recombination lifetime.     

Influence on the sp3/sp2 character of the carbon on the insertion of nitrogen in RFMS carbon nitride films

RFMS carbon nitride films have been elaborated at several substrate temperatures between 150 °C and 450 °C, where they evolve from a highly resistive to highly conductive comportment. Their local structure has been determined from X-ray photoemission, Raman and infrared spectroscopic results. The films composition has been measured by nuclear reaction analysis and elastic recoil detection.We will correlate the strong modifications of the electronic properties of the films to their well characterized structural changes. We will show how the substrate temperature acts on the incorporation of nitrogen in carboneous RFMS films and which is the resulting consequence on the sp³/sp² character of the carbon network.     

Contemporary militant extremism: A linguistic approach to scale development.

In this article, the authors describe procedures used in the development of a new scale of militant extremist mindset. A 2-step approach consisted of (a) linguistic analysis of the texts produced by known terrorist organizations and selection of statements from these texts that reflect the mindset of those belonging to these organizations and (b) analyses of the structural properties of the scales based on 132 selected statements. Factor analysis of militant extremist statements with participants (N = 452) from Australia, Serbia, and the United States produced 3 dimensions: (a) justification and advocacy of violence (War factor), (b) violence in the name of God (God factor), and (c) blaming Western nations for the problems in the world today (West factor). We also report the distributions of scores for the 3 subscales, mean differences among the 3 national samples, and correlations with a measure of dogmatism (M. Rokeach, 1956). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

CONTROLLED AGGREGATION OF POLYMER LATICES PART 1. SYNTHESIS AND CHARACTERIZATION OF A MODEL SYSTEM

As a prerequisite for studying the controlled aggregation of polymer colloids, a model system was obtained in two major steps: synthesis of a monodisperse polystyrene latex and cleaning of the resultant colloid. The first step was an emulsion polymerization process in which the particle size was controlled by the surfactant concentration. Serum replacement was used in the second step to remove undesired chemicals, involved or produced in the previous step. Electrophoretic properties and surface charge densities of the latices produced were obtained by means of ξ potential measurements and conductometric titrations. These parameters are discussed in connection with the characteristics of the polymer material and process variables.     

Talking with patients about their use of alternative therapies

Discussion of alternative therapy use provides the primary care clinician with important information regarding patients' health-related practices and beliefs. The dialogue itself may also serve as an important foundation for effective and mutually rewarding doctor-patient relationships. This article reviews demographic and ethnographic data that document patterns and rationales of complementary and alternative therapy use in the United States. Specific principles to facilitate discussion in counseling patients who use, or who consider use of, alternative therapies are discussed.     

Dental hygienists in the United States: results of an ADA survey

The Survey Center of the American Dental Association conducts an annual survey of approximately 5 percent of all private practitioners in the United States. This survey is sent to a randomly selected group of dentists in private practice, including general practitioners and specialists and ADA members and nonmembers. It attempts to collect information on various practice characteristics such as work schedules, patient visits, non-dentist staff employment, expenses and wages. Using information from the 1991 to 1995 Survey of Dental Practice reports, this article examines the employment of dental hygienists.