27 resultados para network theory and analysis
                                
Resumo:
In this preliminary study eighteen p-substituted benzoic acid [(5-nitro-thiophen-2-yl)-methylene]-hydrazides with antimicrobial activity were evaluated against multidrug-resistant Staphylococcus aureus, correlating the three-dimensional characteristics of the ligands with their respective bioactivities. The computer programs Sybyl and CORINA were used, respectively, for the design and three-dimensional conversion of the ligands. Molecular interaction fields were calculated using GRID program. Calculations using Volsurf resulted in a statistically consistent model with 48 structural descriptors showing that hydrophobicity is a fundamental property in the analyzed biological response.
                                
Resumo:
This paper analyses the applicability of the main enterprise internationalization theories to the entry of the multinational corporations into Brazil, throughout five phases of Brazilian economy, from 1850 to nowadays. It seeks to verify the explanation power of each theory over the FDI flows in Brazil. It concludes that there is a contingency relation between the theories and the phases of the economy, and. it shows such relationship in a table. In addition, it concludes that the most powerful theory along the researched period was Dunning`s eclectic paradigm, mainly due to the Localization considerations. Theoretical propositions are put forward as a contribution to future research.
                                
Resumo:
Atopic dermatitis (AD) is a chronic, inflammatory skin disease with a high prevalence and complex pathogenesis. The skin of AD patients is usually colonized by Staphylococcus aureus (S. aureus); its exotoxins may trigger or enhance the cutaneous inflammation. Several mediators are related to the AD immune imbalance and interleukin-18 (IL-18), an inflammatory cytokine, may play a role in the atopic skin inflammation. To evaluate peripheral blood mononuclear cells (PBMC) proliferation response to staphylococcal enterotoxins A (SEA) and B (SEB) and the levels of IL-18 in adults with AD. Thirty-eight adult patients with AD and 33 healthy controls were analysed. PBMC were stimulated with SEA and SEB, phytohemaglutinin (PHA), pokeweed (PWM), tetanus toxoid (TT) and Candida albicans (CMA). IL-18 secretion from PBMC culture supernatants and sera were measured by ELISA. A significant inhibition of the PBMC proliferation response to SEA, PHA, TT and CMA of AD patients was detected (P <= 0.05). Furthermore, increased levels of IL-18 were detected both in sera and non-stimulated PBMC culture supernatants from AD patients (P <= 0.05). A decreased PBMC proliferation response to distinct antigens and mitogens (TT, CMA, SEA and PHA) in adults with AD suggest a compromised immune profile. IL-18 secretion from AD upon stimulation was similar from controls, which may indicate a diverse mechanism of skin inflammation maintained by Staphylococcus aureus. On the other hand, augmented IL-18 secretion from AD sera and non-stimulated cell culture may enhance the immune dysfunction observed in AD, leading to constant skin inflammation.
                                
Resumo:
Background Mucosal leishmaniasis is caused mainly by Leishmania braziliensis and it occurs months or years after cutaneous lesions. This progressive disease destroys cartilages and osseous structures from face, pharynx and larynx. Objective and methods The aim of this study was to analyse the significance of clinical and epidemiological findings, diagnosis and treatment with the outcome and recurrence of mucosal leishmaniasis through binary logistic regression model from 140 patients with mucosal leishmaniasis from a Brazilian centre. Results The median age of patients was 57.5 and systemic arterial hypertension was the most prevalent secondary disease found in patients with mucosal leishmaniasis (43%). Diabetes, chronic nephropathy and viral hepatitis, allergy and coagulopathy were found in less than 10% of patients. Human immunodeficiency virus (HIV) infection was found in 7 of 140 patients (5%). Rhinorrhea (47%) and epistaxis (75%) were the most common symptoms. N-methyl-glucamine showed a cure rate of 91% and recurrence of 22%. Pentamidine showed a similar rate of cure (91%) and recurrence (25%). Fifteen patients received itraconazole with a cure rate of 73% and recurrence of 18%. Amphotericin B was the drug used in 30 patients with 82% of response with a recurrence rate of 7%. The binary logistic regression analysis demonstrated that systemic arterial hypertension and HIV infection were associated with failure of the treatment (P < 0.05). Conclusion The current first-line mucosal leishmaniasis therapy shows an adequate cure but later recurrence. HIV infection and systemic arterial hypertension should be investigated before start the treatment of mucosal leishmaniasis. Conflicts of interest The authors are not part of any associations or commercial relationships that might represent conflicts of interest in the writing of this study (e.g. pharmaceutical stock ownership, consultancy, advisory board membership, relevant patents, or research funding).
                                
Resumo:
Carpenter syndrome, a rare autosomal recessive disorder characterized by a combination of craniosynostosis, polysyndactyly, obesity, and other congenital malformations, is caused by mutations in RAB23, encoding a member of the Rab-family of small GTPases. In 15 out of 16 families previously reported, the disease was caused by homozygosity for truncating mutations, and currently only a single missense mutation has been identified in a compound heterozygote. Here, we describe a further 8 independent families comprising 10 affected individuals with Carpenter syndrome, who were positive for mutations in RAB23. We report the first homozygous missense mutation and in-frame deletion, highlighting key residues for RAB23 function, as well as the first splice-site mutation. Multi-suture craniosynostosis and polysyndactyly have been present in all patients described to date, and abnormal external genitalia have been universal in boys. High birth weight was not evident in the current group of patients, but further evidence for laterality defects is reported. No genotype-phenotype correlations are apparent. We provide experimental evidence that transcripts encoding truncating mutations are subject to nonsense-mediated decay, and that this plays an important role in the pathogenesis of many RAB23 mutations. These observations refine the phenotypic spectrum of Carpenter syndrome and offer new insights into molecular pathogenesis. (C) 2011 Wiley-Liss, Inc.
                                
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A theory of bifurcation equivalence for forced symmetry breaking bifurcation problems is developed. We classify (O(2), 1) problems of corank 2 of low codimension and discuss examples of bifurcation problems leading to such symmetry breaking.
                                
Resumo:
In this paper we present results for the systematic study of reversible-equivariant vector fields - namely, in the simultaneous presence of symmetries and reversing symmetries - by employing algebraic techniques from invariant theory for compact Lie groups. The Hilbert-Poincare series and their associated Molien formulae are introduced,and we prove the character formulae for the computation of dimensions of spaces of homogeneous anti-invariant polynomial functions and reversible-equivariant polynomial mappings. A symbolic algorithm is obtained for the computation of generators for the module of reversible-equivariant polynomial mappings over the ring of invariant polynomials. We show that this computation can be obtained directly from a well-known situation, namely from the generators of the ring of invariants and the module of the equivariants. (C) 2008 Elsevier B.V, All rights reserved.
                                
Resumo:
We present the first-principle electronic structure calculation on an amorphous material including many-body corrections within the GW approximation. We show that the inclusion of the local field effects in the exchange-correlation potential is crucial to quantitatively describe amorphous systems and defect states. We show that the mobility gap of amorphous silica coincides with the band gap of quartz, contrary to the traditional picture and the densityfunctional theory results. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
                                
Resumo:
The Mario Schenberg gravitational wave detector has started its commissioning phase at the Physics Institute of the University of Sao Paulo. We have collected almost 200 h of data from the instrument in order to check out its behavior and performance. We have also been developing a data acquisition system for it under a VXI System. Such a system is composed of an analog-to-digital converter and a GPS receiver for time synchronization. We have been building the software that controls and sets up the data acquisition. Here we present an overview of the Mario Schenberg detector and its data acquisition system, some results from the first commissioning run and solutions for some problems we have identified.
                                
Resumo:
We observe experimentally a deviation of the radius of a Bose-Einstein condensate from the standard Thomas-Fermi prediction, after free expansion, as a function of temperature. A modified Hartree-Fock model is used to explain the observations, mainly based on the influence of the thermal cloud on the condensate cloud.
                                
Resumo:
Using Sigma theory we show that for large classes of groups G there is a subgroup H of finite index in Aut(G) such that for phi is an element of H the Reidemeister number R(phi) is infinite. This includes all finitely generated nonpolycyclic groups G that fall into one of the following classes: nilpotent-by-abelian groups of type FP(infinity); groups G/G `` of finite Prufer rank; groups G of type FP(2) without free nonabelian subgroups and with nonpolycyclic maximal metabelian quotient; some direct products of groups; or the pure symmetric automorphism group. Using a different argument we show that the result also holds for 1-ended nonabelian nonsurface limit groups. In some cases, such as with the generalized Thompson`s groups F(n,0) and their finite direct products, H = Aut(G).
                                
Resumo:
In order to investigate the chemical profile of 14 specimens of Aplysina spp. marine sponges, we have developed a method based on LC-PDA-MS for the detection of bromotyrosine-derived metabolites. The method enabled the dereplication of three distinct chemotypes of bromotyrosine-derived compounds based on UV absorptions, which were further refined by electrospray ionization-mass spectrometry analysis of the brominated quasi-molecular ion clusters. This procedure led to either a single compound assignment, or a maximum of two possible isobaric compounds. The dereplication study indicated that the chemical profile of the 14 specimens of Aplysina spp. analyzed presented practically the same dibromotyrosine-derived compounds. The results obtained suggested a possible biogenetic pathway for the formation of dibromotyrosine-derived compounds of wide occurrence in Verongida sponges.