Vanadium-modified molecular sieves: preparation, characterization and catalysis

Vanadium-containing molecular sieves are redox catalysts and are good candidates as substitutes for oxide-supported V2O5 in a number of reactions. These materials have the advantage of presenting better dispersion of vanadium species, as well as shape-selective properties and controllable acidities. They may be prepared by one-pot synthesis or by post-synthesis methods and a number of techniques such as diffuse reflectance UV-visible spectroscopy, 51V nuclear magnetic resonance and electron paramagnetic resonance, to name but a few, have been used to characterize these materials. In this review, methods of preparation of vanadium-modified molecular sieves, their characterization and applications in catalysis are discussed.46346

EM TEMPOS GLOBAIS, UM “NOVO” LOCAL: a Ford na Bahia

O artigo analisa a dinâmica da Região Metropolitana de Salvador (RMS) a partir da implantação da Ford, discutindo a perspectiva do ‘lugar’ (a periferia metropolitana), dentro de uma relação assimétrica com os negócios globais na era da flexibilidade. O texto caracteriza o complexo Ford de Camaçari a partir da reestruturação produtiva e das mudanças na organização e funcionamento dos territórios e, na segunda parte, seus impactos sobre a periferia metropolitana de Salvador. Na conclusão demonstra que as mesmas circunstâncias que permitiram a vinda da montadora para Camaçari constrangem as ambições originais de melhor equacionamento entre crescimento econômico e progresso social: a flexibilidade dos novos arranjos, que tornam os espaços periféricos estratégicos, compromete o “enraizamento” do investimento; a “produção enxuta”, exígua de emprego e diligente na sua precarização, inibe os benefícios sociais. PALAVRAS CHAVE: reestruturação produtiva, mercado de trabalho, indústria automobilística, periferia metropolitana, segregação socioespacial. IN GLOBAL TIMES, A “NEW” PLACE: Ford in Bahia Ângela Franco This paper makes an analysis of the dynamics of the Metropolitan Area of Salvador (in Portuguese, RMS) starting from the implantation of Ford, discussing the perspective of the ‘local’ (the metropolitan periphery), inside of an asymmetrical relationship with global businesses in the age of flexibility. The Ford Automotive Compound is caracterized in the first part of the paper from its productive reestructuring and changes in the organization and work of territories, and, in the second part, from its impact on the the metropolitan periphery from Salvador. In its conclusion it demonstrates that the same circumstances that allowed the arrival of the automotive maker in Camaçari constrain the original ambitions of better ratio between economical growth and social progress: the flexibility of the new automotive production methods, making peripheric spaces strategic, compromises on the permanence of the investments; and the “streamlined production”, easy on job production and hard on job flexibilization inhibit social benefits. KEYWORDS: productive restructuring, job market, automobile industry, metropolitan periphery, socioespatial segregation. EN PERIODE DE MONDIALISATION, UN “NOUVEAU” LOCAL: Ford à Bahia Ângela Franco Cet article traite de l’analyse de la dynamique de la Région Métropolitaine de Salvador (RMS), à partir de l’implantation de l’usine Ford. On y discute de la perspective du “lieu” (la périphérie métropolitaine), dans une relation asymétrique avec les affaires globales à une époque de flexibilité. On y caractérise le complexe Ford de Camaçari à partir de la restructuration productive et des changements dans l’organisation et le fonctionnement des territoires. Ses impacts sur la périphérie métropolitaine de Salvador sont présentés dans la deuxième partie. En conclusion, on y démontre que ce sont les mêmes circonstances qui ont permis l’arrivée de l’usine de montage à Camaçari qui représentent une contrainte pour les ambitions qui, à l’origine, voulaient atteindre une meilleure équation entre la croissance économique et le progrès social. La flexibilité de ces nouveaux arrangements, qui rendent les espaces périphériques stratégiques, compromet “l’enracinement” des investissements, la “production exiguë”, l’exiguïté des emplois et la diligence dans leur précarisation, elle inhibe les avantages sociaux. MOTS-CLÉS: restructuration productive, marché du travail, industrie automobile, périphérie métropolitaine, ségrégation sociale et spatiale. Publicação Online do Caderno CRH: http://www.cadernocrh.ufba.b

BALB/c Mice Infected with Antimony Treatment Refractory Isolate of Leishmania braziliensis Present Severe Lesions due to IL-4 Production

Leishmaniasis is a neglected disease that affects more than 12 million people worldwide. In Brazil, the cutaneous disease is more prevalent with about 28,000 new cases reported each year, and L. braziliensis is the main causative agent. The interesting data about the infection with this parasite is the wide variety of clinical manifestations that ranges from single ulcerated lesions to mucocutaneous and disseminated disease. However, experimental models to study the infection with this parasite are difficult to develop due to high resistance of most mouse strains to the infection, and the mechanisms underlying the distinct manifestations remain poorly understood. Here, the authors use a mouse experimental model of infection with different L. braziliensis isolates, known to induce diseases with distinct severity in the human hosts, to elucidate immune mechanisms that may be involved in the different manifestations. They showed that distinct parasite isolates may modulate host response, and increased IL-4 production and Arg I expression was related to more severe disease, resulting in longer length of disease with larger lesions and reduced parasite clearance. These findings may be useful in the identification of immunological targets to control L. braziliensis infection and potential clinical markers of disease progression

5-Hydroxymethylfurfural and Furfural Base-Free Oxidation over AuPd Embedded Bimetallic Nanoparticles

International audienceThe heterogeneous catalytic partial oxidation of alcohols and aldehydes in the liquid phase usually needs the addition of a homogeneous base, which in turn makes the products’ recovery cumbersome, and can further induce undesired side reactions. In the present work, we propose the use of novel catalysts based on metallic Au, Pd and bimetallic AuPd nanoparticles embedded in a titanosilicate matrix. The as-prepared catalysts showed good efficiency in the base-free partial oxidation of furfural and 5-hydroxymethylfurfural. Au4Pd1@SiTi catalyst showed high selectivity (78%) to monoacids (namely, 5-formyl-2-furancarboxylic acid and 5-hydroxymethyl-2-furancarboxylic acid) at 50% 5-hydroxymethylfurfural (HMF) conversion. The selectivity even reached 83% in the case of furfural oxidation to furoic acid (at 50% furfural conversion). The performances of the catalysts strongly depended on the Au–Pd ratio, with an optimal value of 4:1. The pH of the solution was always below 3.5 and no leaching of metals was observed, confirming the stabilization of the metal nanoparticles within the titanosilicate host matrix

Palladium nanoparticles supported on mesoporous biocarbon from coconut shell for ethanol electro-oxidation in alkaline media

Abstract Palladium nanoparticles supported on carbon Vulcan XC72 (Pd/C) and biocarbon (Pd/BC) synthesized by sodium borohydride process were used as catalysts for ethanol electro-oxidation in alkaline media. The biocarbon (BC) from coconut shell with mesoporous and high surface area (792 m2 g−1) was obtained by carbonization at 900 °C and the hydrothermal treatment in a microwave oven. The D-band and G-band intensity ratio (I D/I G) from Raman analysis showed high disorder of the biocarbon, while X-ray photoelectron spectroscopy (XPS) suggests higher percentage of oxygen groups on the surface of biocarbon than of Vulcan XC72. From X-ray diffraction (XRD), it was observed peaks in 2θ degree related to the face centered cubic (fcc) structure of palladium and the mean crystallite sizes calculated based on the diffraction peak of Pd (220) were 5.6 nm for Pd/C and 5.3 nm for Pd/BC. Using Transmission Electron Microscope (TEM), it was observed particles well dispersed on both carbons support materials. The electrocatalytic activity of the materials was investigated by cyclic voltammetry (CV) and chronoamperometry (CA) experiments. The peak current density (on CV experiments) from ethanol electro-oxidation on Pd/BC was 50% higher than on Pd/C, while the current density measured at 15 min of CA experiments was 80% higher on Pd/BC than on Pd/C. The higher catalytic activity of Pd/BC might be related to the large surface area of the biocarbon (792 m2 g−1) vs (239 m2 g−1) of Vulcan carbon, the defects of the biocarbon structure and higher amount of oxygen on the surface than Carbon Vulcan XC 72