Graphene on metals: a Van der Waals density functional study

We use density functional theory (DFT) with a recently developed van der Waals density functional (vdW-DF) to study the adsorption of graphene on Al, Cu, Ag, Au, Pt, Pd, Co and Ni(111) surfaces. In constrast to the local density approximation (LDA) which predicts relatively strong binding for Ni,Co and Pd, the vdW-DF predicts weak binding for all metals and metal-graphene distances in the range 3.40-3.72 \AA. At these distances the graphene bandstructure as calculated with DFT and the many-body G$_0$W$_0$ method is basically unaffected by the substrate, in particular there is no opening of a band gap at the $K$-point.Comment: 4 pages, 3 figure

Preferências alimentares de insetos por espécies de Piperaceae, observadas na cidade de São Paulo, Brasil

Piperaceae species have been placed among the basal angiosperm and are adapted to a variety of habitats including moist forests, secondary vegetation and dry high lands. The major anatomical/morphology features are of small trees, vines, and shrubs for Piper species, while the epiphytic and succulent characteristics are predominant forms among Peperomia species. Their secondary chemistry can be mostly represented by amides, phenylpropanoids/lignoids, and chromenes in addition to a phletoria of biosynthetically mixed-origin secondary compounds. Although several amides and lignans are known as insecticides, several phytophagous insects, among which some considered pests of economic importance, have been observed feeding vigorously on Piperaceae species. Herein we describe the feeding preferences of fourteen phytophagous species of Coleoptera, Lepidoptera and Hemiptera over approximately fifty Piperaceae species observed in São Paulo, SP, Brazil, in a long-term basis.As espécies de Piperaceae têm sido posicionadas entre as angiospermas basais e são frequentemente encontradas em habitats diversificados que incluem matas ciliares, vegetação secundária e campos rupestres. As espécies de Piper possuem hábitos de plantas herbáceas, arboretos e trepadeiras enquanto que, no caso de Peperomia, é freqüente o hábito de epífitas e suculentas. As classes de metabólitos secundários que caracterizam espécies de Piperaceae são amidas, fenilpropanóides/lignóides e cromenos, além de diversos outros de origem biossintética mista de menor representatividade. Apesar de muitos desses possuírem atividades inseticidas, diversos insetos fitófagos, alguns considerados pragas de importância econômica, foram observados alimentando-se de espécies de Piperaceae. Neste trabalho são relatadas as preferências alimentares de quatorze espécies fitófagas de Coleoptera, Lepidoptera e Hemiptera sobre aproximadamente cinqüenta espécies de Piperaceae observadas em São Paulo, SP, Brasil, durante um período de quatro anos

Sustained high-level expression of human factor IX (hFIX) after liver-targeted delivery of recombinant adeno-associated virus encoding the hFIX gene in rhesus macaques

The feasibility, safety, and efficacy of liver-directed gene transfer was evaluated in 5 male macaques (aged 2.5 to 6.5 years) by using a recombinant adeno-associated viral (rAAV) vector (rAAV-2 CAGG-hFIX) that had previously mediated persistent therapeutic expression of human factor IX (hFIX; 6%-10% of physiologic levels) in murine models. A dose of 4 × 1012 vector genomes (vgs)/kg of body weight was administered through the hepatic artery or portal vein. Persistence of the rAAV vgs as circular monomers and dimers and high-molecular-weight concatamers was documented in liver tissue by Southern blot analysis for periods of up to 1 year. Vector particles were present in plasma, urine, or saliva for several days after infusion (as shown by polymerase chain reaction analysis), and the vgs were detected in spleen tissue at low copy numbers. An enzyme-linked immunosorption assay capable of detecting between 1% and 25% of normal levels of hFIX in rhesus plasma was developed by using hyperimmune serum from a rhesus monkey that had received an adenoviral vector encoding hFIX. Two macaques having 3 and 40 rAAV genome equivalents/cell, respectively, in liver tissue had 4% and 8% of normal physiologic plasma levels of hFIX, respectively. A level of hFIX that was 3% of normal levels was transiently detected in one other macaque, which had a genome copy number of 25 before abrogation by a neutralizing antibody (inhibitor) to hFIX. This nonhuman-primate model will be useful in further evaluation and development of rAAV vectors for gene therapy of hemophilia B. © 2002 by The American Society of Hematology

Lixiviação de potássio com aplicação superficial de dejetos líquidos de suínos.

A demanda mundial por carnes tem aumentado a criação e abate de animais, gerando resíduos como os dejetos líquidos de suínos (DLS) que são utilizados como fertilizante em pastagens e culturas. Porém, o potássio contido neste fertilizante pode ser perdido por lixiviação. O objetivo deste trabalho foi mensurar a lixiviação de potássio proveniente da aplicação superficial de DLS em diferentes doses. O experimento foi conduzido em delineamento inteiramente casualizado com cinco tratamentos (90, 180, 270 e 360 m3 ha-1 de DLS) e uma testemunha e cinco repetições. Foram utilizadas colunas de lixiviação de tubos de PVC com 250 mm de diâmetro, subdivididos em camadas de 20 e 25 cm, totalizando 65 cm de profundidade. A determinação da quantidade de água lixiviada nas colunas de lixiviação, e as coletas das amostras de água nas garrafas PET foram realizadas a cada 72h, de acordo com a aplicação de uma lâmina de água de 20mm. As determinações analíticas do potássio lixiviado na água percolada foram realizadas no laboratório de solos da Embrapa Solos por meio de espectrometria de plasma de emissão atômica. As coletas foram efetuadas até 30 dias após a aplicação dos DLS. Observou-se variação significativa para a coleta efetuada no sexto dia, com ajuste de uma curva de regressão com tendência linear, indicando que doses maiores de DLS causam maior lixiviação de K. A lixiviação de K foi de 1,36% do total de K aplicado. A lixiviação entre o décimo segundo e décimo oitavo dia após a aplicação dos DLS superou as demais

Global Demethylation of Rat Chondrosarcoma Cells after Treatment with 5-Aza-2′-Deoxycytidine Results in Increased Tumorigenicity

Abnormal patterns of DNA methylation are observed in several types of human cancer. While localized DNA methylation of CpG islands has been associated with gene silencing, the effect that genome-wide loss of methylation has on tumorigenesis is not completely known. To examine its effect on tumorigenesis, we induced DNA demethylation in a rat model of human chondrosarcoma using 5-aza-2-deoxycytidine. Rat specific pyrosequencing assays were utilized to assess the methylation levels in both LINEs and satellite DNA sequences following 5-aza-2-deoxycytidine treatment. Loss of DNA methylation was accompanied by an increase in invasiveness of the rat chondrosarcoma cells, in vitro, as well as by an increase in tumor growth in vivo. Subsequent microarray analysis provided insight into the gene expression changes that result from 5-aza-2-deoxycytidine induced DNA demethylation. In particular, two genes that may function in tumorigenesis, sox-2 and midkine, were expressed at low levels in control cells but upon 5-aza-2-deoxycytidine treatment these genes became overexpressed. Promoter region DNA analysis revealed that these genes were methylated in control cells but became demethylated following 5-aza-2-deoxycytidine treatment. Following withdrawal of 5-aza-2-deoxycytidine, the rat chondrosarcoma cells reestablished global DNA methylation levels that were comparable to that of control cells. Concurrently, invasiveness of the rat chondrosarcoma cells, in vitro, decreased to a level indistinguishable to that of control cells. Taken together these experiments demonstrate that global DNA hypomethylation induced by 5-aza-2-deoxycytidine may promote specific aspects of tumorigenesis in rat chondrosarcoma cells

Direct EPR Detection of Nitric Oxide in Mice Infected with the Pathogenic Mycobacterium Mycobacterium tuberculosis

It has been shown that treatment of mice preinfected with Mycobacterium tuberculosis with spin NO traps (iron complexes with diethyldithiocarbamate) enables detection of large amounts of NO in internal organs 2 and 4 weeks after infection (up to 55–57 μmol/kg of wet lung tissue accumulated with spin NO traps during 30 min). The animals were infected with the drug-sensitive laboratory strain H37Rv and a clinical isolate nonrespondent to antituberculous drugs (the multidrug-resistant strain of M. tuberculosis) obtained from a patient with an active form of tuberculosis. Two weeks after infection with the multidrug-resistant strain, the NO level in the lungs, spleen, liver and kidney increased sharply concurrently with slight lesions of lung tissue. A reverse correlation, i.e., low level of NO in the lungs and other internal organs and extensive injury of lung tissue, was established for H37Rv-infected mice. Four weeks after infection, NO production in the lungs increased dramatically for both M. tuberculosis strains resulting in 80–84% damage of lung tissue. The lesion is suggested to be due to the development of defense mechanisms in M. tuberculosis counteracting NO effects