Marina M. Dias

Five-dimensional f(R) braneworld models

After incorporating the f(R) gravity into the general braneworld sum rules scope, it is shown that some particular class of warped five dimensional nonlinear braneworld models, which may be interesting for the hierarchy problem solution, still require a negative tension brane. For other classes of warp factors (suitable and not suitable for approaching the hierarchy problem) it is not necessary any negative brane tension in the compactification scheme. In this vein, it is argued that in the bulk f(R) gravity context, some types of warp factors may be useful for approaching the hierarchy problem and for evading the necessity of a negative brane tension in the compactification scheme.

Perspectives for an Elko phenomenology using monojets at the 14 TeV LHC

The aim of this work is to explore the possibility to discover a fermionic field with mass dimension one, the Elko field, in the 14 TeV Large Hadron Collider (LHC), in processes with missing energy and one jet. We explore the possibility of a triple coupling with the Higgs field, generating also a contribution to the Elko mass term, and suggest some possibilities for future studies in this field.

Coagulation Factor XII Gene Mutation in Brazilian Families with Hereditary Angioedema with Normal C1 Inhibitor

Background: Hereditary angioedema (HAE) with normal C1 inhibitor (C1-INH) is a rare disorder. Mutations of the gene encoding coagulation factor XII have been identified in a subset of patients with this condition. Our aim was to investigate mutations in the F12 gene in patients with HAE with normal C1-INH from Brazil. Methods: We studied 5 Brazilian families with index female patients who presented with recurrent angioedema with normal C1-INH and C4 levels. Genomic DNA was isolated from whole blood and PCR was performed. Mutations were detected by the sequencing of exon 9 of the F12 gene and allelic discrimination. Results: The c.983C>A (p.Thr328Lys) mutation was identified in 16 subjects, from 4 of the 5 families studied, including 8 patients with symptoms of HAE with normal C1-INH (87.5% women) and 8 subjects asymptomatic for HAE (25% women). Mean age at onset of symptoms among the FXII-HAE patients was 13.8 years (range 6-25 years). Recurrent abdominal pain (100%) and subcutaneous angioedema (87.5%) were the most frequent clinical presentations. Two patients presented with associated laryngeal edema. In keeping with previous observations in patients with both C1-INH-HAE and HAE with normal C1-INH, all 7 women with FXII-HAE reported triggering or worsening of symptoms upon intake of estrogen-containing oral contraceptives and/or pregnancy. Conclusions: We report for the first time in Brazil a mutation in the F12 gene as a likely cause of HAE with normal C1-INH in patients with recurrent attacks of angioedema and/or abdominal pain. A higher frequency of abdominal pain attacks and onset of symptoms at a younger age were observed among Brazilian patients when compared to those from other parts of the world.

Higher-order theories from the minimal length

We show that the introduction of a minimal length in the context of noncommutative space–time gives rise (after some considerations) to higher-order theories. We then explicitly demonstrate how these higher-derivative theories appear as a generalization of the standard electromagnetism and general relativity by applying a consistent procedure that modifies the original Maxwell and Einstein–Hilbert actions. In order to set a bound on the minimal length, we compare the deviations from the inverse-square law with the potentials obtained in the higher-order theories and discuss the validity of the results. The introduction of a quantum bound for the minimal length parameter β in the higher-order QED allows us to lower the actual limits on the parameters of higher-derivative gravity by almost half of their order of magnitude.

Bronchial hyperreactivity induced by tropomyosins from cockroach and shrimp: a mouse model to study in vivo cross-reactivity

Methods Balb/c mice, 4 to 6 weeks-old, were sensitized twice with 50μg of rPer a 7 or nLit v 1 intraperitoneally with 1 mg alum, and challenged with 50μg of rPer a 7 or nLit v 1 intranasally for three days. A group was sensitized with rPer a 7 and challenged with nLit v 1 under same conditions. Controls received saline on same days. Twenty-four hours after the last challenge, mice were ventilated with FlexiVent, and in vivo bronchial hyperresponsiveness was evaluated with increased doses of inhaled methacholine (6.25, 12.5, 25 and 50mg/ml). After ventilation, bronchoalveolar lavage fluid (BALF) was collected and cell counts were performed.