Use of natural rubber membranes as support for powder TiO2 and Ag/TiO2 photocatalysts

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The purpose of this study was to synthesize TiO2-polymer composites able to act as photocatalyst membranes. TiO2 catalysts were prepared using the sol-gel method to contain 0.0, 0.5, 1.0, and 2.0 wt.% of embedded Ag particles, subsequently incorporated into natural rubber latex at a weight fraction of 15%. Samples of these ceramic powders were suspended in a latex emulsion (natural rubber), cast in Petri dishes and slowly dried in an oven. The resulting materials were evaluated by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, diffuse reflectance spectroscopy, differential scanning calorimetry, thermogravimetry, and photocatalytic assaying using methylene blue as an organic pollutant reference. All composite membranes exhibited good photoactivity conferred by TiO2 powder, with 98% dye fading after 300 min of ultraviolet irradiation.The purpose of this study was to synthesize TiO2-polymer composites able to act as photocatalyst membranes. TiO2 catalysts were prepared using the sol-gel method to contain 0.0, 0.5, 1.0, and 2.0 wt.% of embedded Ag particles, subsequently incorporated in273575583CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFUNDECT - FUNDAÇÃO DE APOIO AO DESENVOLVIMENTO DO ENSINO, CIÊNCIA E TECNOLOGIA DO ESTADO DE MATO GROSSO DO SUL |Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)sem informaçãosem informaçãosem informaçãosem informaçãoThe authors wish to thank the Brazilian funding agencies Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), and Fundação de Apoio ao Desenvolvimento do Ensino, Ciênci

On the mass‐to‐light ratios of fossil groups. Are they simply dark clusters?

Defined as X‐ray bright galaxy groups with large differences between the luminosities of their brightest and second brightest galaxies, ‘fossil groups’ are believed to be some of the oldest galaxy systems in the Universe. They have therefore been the subject of much recent research. In this work we present a study of 10 fossil group candidates with an average of 33 spectroscopically confirmed members per group, making this the deepest study of its type to date. We also use these data to perform an analysis of the luminosity function of our sample of fossil groups. We confirm the high masses previously reported for many of fossil systems, finding values more similar to those of clusters than of groups. We also confirm the high dynamical mass‐to‐light ratios reported in many previous studies. While our results are consistent with previous studies in many ways, our interpretation is not. This is because we show that, while the luminosities of the bright central galaxies (BCGs) in these systems are consistent with their high dynamical masses, their richnesses (total number of galaxies above some canonical value) are extremely low. This leads us to suggest a new interpretation of fossil systems in which the large differences between the luminosities of their brightest and second brightest galaxies are simply the result of the high BCG luminosities and low richnesses, while the high masses and low richnesses also explain the high mass‐to‐light ratios. Our results therefore suggest that fossil systems can be characterized as cluster‐like in their masses and BCG luminosities, but possessing the richnesses and optical luminosities of relatively poor groups. These findings are not predicted by any of the current models for the formation of fossil groups. Therefore, if this picture is confirmed, current ideas about the formation and evolution of fossil systems will need to be reformulated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89559/1/j.1365-2966.2011.19625.x.pd

In vitro screening of cytotoxic activity of euphol from Euphorbia tirucalli on a large panel of human cancer-derived cell lines

A large number of classic antineoplastic agents are derived from plants. Euphorbia tirucalli L. (Euphorbiaceae) is a subtropical and tropical plant, used in Brazilian folk medicine against many diseases, including cancer, yet little is known about its true anticancer properties. The present study evaluated the antitumor effect of the tetracyclic triterpene alcohol, euphol, the main constituent of E. tirucalli in a panel of 73 human cancer lines from 15 tumor types. The biological effect of euphol in pancreatic cells was also assessed. The combination index was further used to explore euphol interactions with standard drugs. Euphol showed a cytotoxicity effect against several cancer cell lines (IC50 range, 1.41-38.89 µM), particularly in esophageal squamous cell (11.08 µM) and pancreatic carcinoma cells (6.84 µM), followed by prostate, melanoma, and colon cancer. Cytotoxicity effects were seen in all cancer cell lines, with more than half deemed highly sensitive. Euphol inhibited proliferation, motility and colony formation in pancreatic cancer cells. Importantly, euphol exhibited synergistic interactions with gemcitabine and paclitaxel in pancreatic and esophageal cell lines, respectively. To the best of our knowledge, this study constitutes the largest in vitro screening of euphol efficacy on cancer cell lines and revealed its in vitro anti-cancer properties, particularly in pancreatic and esophageal cell lines, suggesting that euphol, either as a single agent or in combination with conventional chemotherapy, is a potential anti-cancer drug.Amazônia Fitomedicamentos Ltda. (grant no. FITO 05/2012) and Barretos Cancer Hospital, all from Brazilinfo:eu-repo/semantics/publishedVersio

The role of T cell subsets and cytokines in the regulation of intracellular bacterial infection

Cellular immune responses are a critical part of the host's defense against intracellular bacterial infections. Immunity to Brucella abortus crucially depends on antigen-specific T cell-mediated activation of macrophages, which are the major effectors of cell-mediated killing of this organism. T lymphocytes that proliferate in response to B. abortus were characterized for phenotype and cytokine activity. Human, murine, and bovine T lymphocytes exhibited a type 1 cytokine profile, suggesting an analogous immune response in these different hosts. In vivo protection afforded by a particular cell type is dependent on the antigen presented and the mechanism of antigen presentation. Studies using MHC class I and class II knockout mice infected with B. abortus have demonstrated that protective immunity to brucellosis is especially dependent on CD8+ T cells. To target MHC class I presentation we transfected ex vivo a murine macrophage cell line with B. abortus genes and adoptively transferred them to BALB/c mice. These transgenic macrophage clones induced partial protection in mice against experimental brucellosis. Knowing the cells required for protection, vaccines can be designed to activate the protective T cell subset. Lastly, as a new strategy for priming a specific class I-restricted T cell response in vivo, we used genetic immunization by particle bombardment-mediated gene transfer

Mitochondrial Preconditioning: A Potential Neuroprotective Strategy

Mitochondria have long been known as the powerhouse of the cell. However, these organelles are also pivotal players in neuronal cell death. Mitochondrial dysfunction is a prominent feature of chronic brain disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD), and cerebral ischemic stroke. Data derived from morphologic, biochemical, and molecular genetic studies indicate that mitochondria constitute a convergence point for neurodegeneration. Conversely, mitochondria have also been implicated in the neuroprotective signaling processes of preconditioning. Despite the precise molecular mechanisms underlying preconditioning-induced brain tolerance are still unclear, mitochondrial reactive oxygen species generation and mitochondrial ATP-sensitive potassium channels activation have been shown to be involved in the preconditioning phenomenon. This review intends to discuss how mitochondrial malfunction contributes to the onset and progression of cerebral ischemic stroke and AD and PD, two major neurodegenerative disorders. The role of mitochondrial mechanisms involved in the preconditioning-mediated neuroprotective events will be also discussed. Mitochondrial targeted preconditioning may represent a promising therapeutic weapon to fight neurodegeneration

Disseminação de vírus em campos de alho cultivado em diferentes sistemas de produção no Brasil

Amostras de quatro regiões produtoras que representam aproximadamente 76% da área de alho plantada no Brasil, foram testadas por RT-PCR para a presença de Onion yellow dwarf virus (OYDV), Leek yellow stripe virus (LYSV), Garlic common latent virus (GCLV), Garlic virus C (Garv-C), Garlic virus D (Garv-D) e Garlic mite-borne filamentous virus (GarMbFV). As amostras (352 bulbos) foram provenientes de cinco sistemas de cultivo: alho tradicional comum (CG), alho tradicional livre de vírus (VFCG), alho nobre não-vernalizado (NVNGSG) e alho nobre vernalizado cultivado por pequenos produtores (VNGSG), e alho nobre vernalizado utilizado por grandes produtores (VNGMG). Infecções múltiplas foram detectadas em 22% das amostras. As espécies de potyvírus foram observadas em todas as regiões. O LYSV prevaleceu sobre OYDV enquanto o carlavírus, GCLV foi o menos disseminado. Garv-C e GarMbFV foram as mais prevalentes entre os allexivírus. O sistema de produção NVNGSG teve uma maior prevalência de LYSV e Garv-C. O sistema de produção CG apresentou a maior prevalência de todas as espécies, especialmente LYSV (94% das amostras). As regiões com maior nível tecnológico tiveram a menor prevalência viral. As informações deste monitoramento, poderão auxiliar no estabelecimento de estratégias visando o aumento da qualidade fitosanitária e da produtividade nacional do alho.Samples from four regions, representing 76% of the garlic growing area in Brazil, were tested by RT-PCR for the presence of Onion yellow dwarf virus (OYDV), Leek yellow stripe virus (LYSV), Garlic common latent virus (GCLV), Garlic virus C (GarV-C), Garlic virus D (GarV-D) and Garlic mite-borne filamentous virus (GarMbFV). The samples (352 bulbs) represented five agricultural systems: traditional common garlic (CG), virus-free common garlic (VFCG), non-vernalized noble garlic (NVNGSG) and vernalized noble garlic cultivated by small growers (VNGSG), and vernalized noble garlic adopted by major growers (VNGMG). Multiple infections were detected in 22% of the samples. Potyvirus species were present in all regions. LYSV prevailed over OYDV while the carlavirus GCLV was less prevalent. GarV-C and GarMbFV were the most prevalent among the allexivirus species. The NVNG production system had a higher prevalence of LYSV and GarV-C. The CG production system, that uses less technology, had the highest prevalence for all species, especially LYSV that prevailed in 94% of the samples. Overall, the regions with higher technological input employing better quality seeds had the lowest viral prevalence for all species. This monitoring provides information to establish a strategy to raise the phytosanitary quality and the national productivity of garlic

An optical and X-ray study of the fossil group RX J1340.6+4018

Fossil groups are systems with one single central elliptical galaxy and an unusual lack of luminous galaxies in the inner regions. The standard explanation for the formation of these systems suggests that the lack of bright galaxies is due to galactic cannibalism. In this study we show the results of an optical and X-ray analysis of RX J1340.6+4018, the prototype fossil group. The data indicates that RX J1340.6+4018 is similar to clusters in almost every sense, dynamical mass, X-ray luminosity, M/L and luminosity function, except for the lack of L* galaxies. There are claims in the literature that fossil systems have a lack of small mass haloes, compared to predictions based on the LCDM scenario. The observational data gathered on this and other fossil groups so far offer no support to this idea. Analysis of the SN Ia/SN II ejecta ratio in the inner and outer regions shows a marginally significant central dominance of SN Ia material. This suggests that either the merger which originated the central galaxy was dry or the group has been formed at early epochs, although better data are needed to confirm this result.Comment: Accepted by AJ; 14 pages, 6 figure