Relativistic three-body model for final state interaction in D+ → K-π+π+ decay

A challenge in mesonic three-body decays of heavy mesons is to quantify the contribution of re-scattering between the final mesons. D decays have the unique feature that make them a key to light meson spectroscopy, in particular to access the Kn S-wave phase-shifts. We built a relativis-tic three-body model for the final state interaction in D+ → K -π+π+ decay based on the ladder approximation of the Bethe-Salpeter equation projected on the light-front. The decay amplitude is separated in a smooth term, given by the direct partonic decay amplitude, and a three-body fully interacting contribution, that is factorized in the standard two-meson resonant amplitude times a reduced complex amplitude that carries the effect of the three-body rescattering mechanism. The off-shell reduced amplitude is a solution of an inhomogeneous Faddeev type three-dimensional integral equation, that includes only isospin 1/2 K -π+ interaction in the S-wave channel. The elastic K-π+ scattering amplitude is parameterized according to the LASS data[1]. The integral equation is solved numerically and preliminary results are presented and compared to the experimental data from the E791 Collaboration[2, 3] and FOCUS Collaboration[4, 5].

Incorporation of dithiooxamide as a complexing agent into cellulose for the removal and pre-concentration of Cu(II) and Cd(II) ions from natural water samples

The present study describes the incorporation of a complexing agent, dithiooxamide, into microcrystalline cellulose for use in the pre-concentration of Cu(II) and Cd(II) ions from aqueous samples. The FTIR spectrum of the adsorbent exhibited an absorption band in the region of 800 cm-1, which confirmed the binding of the silylating agent to the matrix. Elemental analysis indicated the amount of 0.150 mmol g-1 of the complexing agent. The adsorption data were fit to the modified Langmuir equation, and the maximum amount of metal species extracted from the solution, Ns, was determined to be 0.058 and 0.072 mmol g-1 for Cu(II) and Cd(II), respectively. The covering fraction φ, which was 0.39 and 0.48 for Cu(II) and Cd(II), respectively, was used to estimate a 1:2 (metal:ligand) ratio in the formed complex, and a binding model was proposed based on this information. The adsorbent was applied in the pre-concentration of natural water samples and exhibited an enrichment factor of approximately 50-fold for the species studied, which enabled its use in the analysis of trace metals in aqueous samples. The system was validated by the analysis of certified standard (1643e), and the adsorbent was stable for more than 20 cycles, thus enabling its safe reutilization. © 2012 Elsevier B.V. All rights reserved.

Doxorubicin induced dilated cardiomyopathy in a rabbit model: An update

Dilated cardiomyopathy (DCM) is characterized by chamber dilation and cardiac dysfunction. Because of the poor prognosis, models are needed for the investigation of and development of new therapeutic approaches, as well as stem cell therapy. Doxorubicin (DOX), used as chemotherapeutic agent, is reported to be cumulative cardiotoxic causing DCM. The aim of the study was to investigate the onset of systolic dysfunction using echocardiography in rabbits receiving two different doses of DOX (1. mg/kg twice a week and 2. mg/kg once a week). Twenty rabbits were treated with doxorubicin in two different doses for 6. weeks and compared with a control group treated with NaCl 0.9%. The effect of doxorubicin on the myocardium was investigated with histological analysis and scanning electron microscopy of left ventricle (LV), as well as in the interventricular septum (IVS) and right ventricle (RV). The results showed a high mortality rate for rabbits receiving 2. mg/kg once a week. A significant reduction in systolic function was present in animals treated with DOX after 6. weeks, with decreased ejection fraction and shortening fraction. Histology and electron microscopy revealed vacuolization, intracytoplasmic granulation, necrosis and interstitial fibrosis in LV, as well as in the IVS and RV. Doxorubicin induced changes are present in the LV, RV and IVS, and the administration at the dose of 1. mg/kg twice a week for only 6. weeks is safe and sufficient to induce DCM in rabbits. © 2012 Elsevier Ltd.

Photodynamic and Antibiotic Therapy Impair the Pathogenesis of Enterococcus faecium in a Whole Animal Insect Model

Enterococcus faecium has emerged as one of the most important pathogens in healthcare-associated infections worldwide due to its intrinsic and acquired resistance to many antibiotics, including vancomycin. Antimicrobial photodynamic therapy (aPDT) is an alternative therapeutic platform that is currently under investigation for the control and treatment of infections. PDT is based on the use of photoactive dye molecules, widely known as photosensitizer (PS). PS, upon irradiation with visible light, produces reactive oxygen species that can destroy lipids and proteins causing cell death. We employed Galleria mellonella (the greater wax moth) caterpillar fatally infected with E. faecium to develop an invertebrate host model system that can be used to study the antimicrobial PDT (alone or combined with antibiotics). In the establishment of infection by E. faecium in G. mellonella, we found that the G. mellonella death rate was dependent on the number of bacterial cells injected into the insect hemocoel and all E. faecium strains tested were capable of infecting and killing G. mellonella. Antibiotic treatment with ampicillin, gentamicin or the combination of ampicillin and gentamicin prolonged caterpillar survival infected by E. faecium (P = 0.0003, P = 0.0001 and P = 0.0001, respectively). In the study of antimicrobial PDT, we verified that methylene blue (MB) injected into the insect followed by whole body illumination prolonged the caterpillar survival (P = 0.0192). Interestingly, combination therapy of larvae infected with vancomycin-resistant E. faecium, with antimicrobial PDT followed by vancomycin, significantly prolonged the survival of the caterpillars when compared to either antimicrobial PDT (P = 0.0095) or vancomycin treatment alone (P = 0.0025), suggesting that the aPDT made the vancomycin resistant E. faecium strain more susceptible to vancomycin action. In summary, G. mellonella provides an invertebrate model host to study the antimicrobial PDT and to explore combinatorial aPDT-based treatments.

Anti-inflammatory intestinal activity of Arctium lappa L. (Asteraceae) in TNBS colitis model

Ethnopharmacological relevance: In Brazilian traditional medicine, Arctium lappa (Asteraceae), has been reported to relieve gastrointestinal symptoms. Aim of the study: In the present study, we investigated the effects of the lactone sesquiterpene onopordopicrin enriched fraction (ONP fraction) from Arctium lappa in an experimental colitis model induced by 2,4,6 trinitrobenzene sulfonic acid and performed experiments to elucidate the underlying action mechanisms involved in that effect. Materials and methods: ONP fraction (25 and 50 mg/kg/day) was orally administered 48, 24 and 1 h prior to the induction of colitis and 24 h after. The inflammatory response was assessed by gross appearance, myeloperoxidase (MPO) activity, tumor necrosis factor alpha (TNF-α) levels and a histological study of the lesions. We determined cyclooxygenase (COX)-1 and -2 protein expressions by western blotting and immunohistochemistry assays. Results: TNBS group was characterized by increased colonic wall thickness, edema, diffuse inflammatory cell infiltration, increased MPO activity and TNF-α levels. On the contrary, ONP fraction (25 and 50 mg/kg) treatment significantly reduced the macroscopic inflammation scores (p<0.05 and p<0.01, respectively) and morphological alterations associated with an increase in the mucus secretion. Similarly, the degree of neutrophil infiltration and the cytokine levels were significantly ameliorated. Moreover, COX-2 expression was up regulated in TNBS-treated rats. In contrast, ONP fraction (50 mg/kg) administration reduced COX-2 overexpression. Conclusions: We have shown that the ONP fraction obtained from Arctium lappa exert marked protective effects in acute experimental colitis, confirming and justifying, at least in part, the popular use of this plant to treat gastrointestinal diseases. © 2013 Elsevier B.V. All rights reserved.

Intermolecular interactions of the malate synthase of Paracoccidioides spp

Background: The fungus Paracoccidioides spp is the agent of paracoccidioidomycosis (PCM), a pulmonary mycosis acquired by the inhalation of fungal propagules. Paracoccidioides malate synthase (PbMLS) is important in the infectious process of Paracoccidioides spp because the transcript is up-regulated during the transition from mycelium to yeast and in yeast cells during phagocytosis by murine macrophages. In addition, PbMLS acts as an adhesin in Paracoccidioides spp. The evidence for the multifunctionality of PbMLS indicates that it could interact with other proteins from the fungus and host. The objective of this study was to identify and analyze proteins that possibly bind to PbMLS (PbMLS-interacting proteins) because protein interactions are intrinsic to cell processes, and it might be possible to infer the function of a protein through the identification of its ligands. Results: The search for interactions was performed using an in vivo assay with a two-hybrid library constructed in S. cerevisiae; the transcripts were sequenced and identified. In addition, an in vitro assay using pull-down GST methodology with different protein extracts (yeast, mycelium, yeast-secreted proteins and macrophage) was performed, and the resulting interactions were identified by mass spectrometry (MS). Some of the protein interactions were confirmed by Far-Western blotting using specific antibodies, and the interaction of PbMLS with macrophages was validated by indirect immunofluorescence and confocal microscopy. In silico analysis using molecular modeling, dynamics and docking identified the amino acids that were involved in the interactions between PbMLS and PbMLS-interacting proteins. Finally, the interactions were visualized graphically using Osprey software. Conclusion: These observations indicate that PbMLS interacts with proteins that are in different functional categories, such as cellular transport, protein biosynthesis, modification and degradation of proteins and signal transduction. These data suggest that PbMLS could play different roles in the fungal cell. © 2013 de Oliveira et al.; licensee BioMed Central Ltd.

Peripheral kappa and delta opioid receptors are involved in the antinociceptive effect of crotalphine in a rat model of cancer pain

Cancer pain is an important clinical problem and may not respond satisfactorily to the current analgesic therapy. We have characterized a novel and potent analgesic peptide, crotalphine, from the venom of the South American rattlesnake Crotalus durissus terrificus. In the present work, the antinociceptive effect of crotalphine was evaluated in a rat model of cancer pain induced by intraplantar injection of Walker 256 carcinoma cells. Intraplantar injection of tumor cells caused the development of hyperalgesia and allodynia, detected on day 5 after tumor cell inoculation. Crotalphine (6 μg/kg), administered p.o., blocked both phenomena. The antinociceptive effect was detected 1 h after treatment and lasted for up to 48 h. Intraplantar injection of nor-binaltorphimine (50 g/paw), a selective antagonist of κ-opioid receptors, antagonized the antinociceptive effect of the peptide, whereas N,N-diallyl-Tyr-Aib-Phe-Leu (ICI 174,864, 10 μg/paw), a selective antagonist of δ-opioid receptors, partially reversed this effect. On the other hand, D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr amide (CTOP, 20 g/paw), an antagonist of μ-opioid receptors, did not modify crotalphine-induced antinociception. These data indicate that crotalphine induces a potent and long lasting opioid-mediated antinociception in cancer pain. © 2013 Elsevier Inc.

Light front fermion model propagation

In this work we consider the propagation of two fermion fields interacting with each other by the exchange of intermediate scalar bosons in the light front. We obtain the corrections up to fourth order in the coupling constant using hierarchical equations in order to obtain the bound state equation (Bethe - Salpeter equation). © 2013 Chinese Physical Society and IOP Publishing Ltd.

Scaling attractors in interacting teleparallel dark energy

It has been proposed recently the existence of a non-minimal coupling between a canonical scalar field (quintessence) and gravity in the framework of teleparallel gravity, motivated by similar constructions in the context of General Relativity. The dynamics of the model, known as teleparallel dark energy, has been further developed, but no scaling attractor has been found. Here we consider a model in which the non-minimal coupling is ruled by a dynamically changing coefficient α≡f,φ/(f)1/2, with f(φ) an arbitrary function of the scalar field φ. It is shown that in this case the existence of scaling attractors is possible, which means that the universe will eventually enter these scaling attractors, regardless of the initial conditions. As a consequence, the cosmological coincidence problem could be alleviated without fine-tunings. © 2013 IOP Publishing Ltd and Sissa Medialab srl.

Avaliação do potencial tripanocida de diaminas, diaminas de ferroceno e derivados de 1,4-naftoquinonas em cepas de Trypanosoma brucei

Pós-graduação em Biotecnologia - IQ

Sistema multiagente web semântico para gestão de conteúdos educacionais

Pós-graduação em Ciência da Computação - IBILCE

Uma arquitetura multiagente para sistemas de supervisão e controle de processos

Pós-graduação em Ciência da Computação - IBILCE

Confidence and the Stock Market: An Agent-Based Approach

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cyclosporine improves remyelination in diabetic rats submitted to a gliotoxic demyelinating model in the brainstem

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Geraniol-a flavoring agent with multifunctional effects in protecting the gastric and duodenal mucosa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)