Reduction of the model noise in non-linear reconstruction via an efficient calculation of the incident field: application to a 434 MHz Scanner

Microwave tomography has been drastically boosted by the development of efficient reconstruction algorithms based on an iterative solution of the corresponding non-linear inverse problem. The accuracy of the electric field radiated by the antennas of a microwave scanner, inside the target area, has been shown to play a significant role on the overall image quality. Taking into account the antenna environment is of prime importance, especially when operating at low frequency. For instance, the wall of a 60 cm diameter whole-body microwave scanner cannot be neglected at 434 MHz, even when using the immersion technique consisting of putting the target in water. Indeed, at such a frequency, the attenuation introduced by water is not sufficient to avoid multiple reflections on the scanner boundary walls. Consequently, the method of calculating the incident field constitutes a key factor in iteratively solving non-linear inverse problems. The selected technique must accommodate high accuracy while maintaining acceptable calculation complexity. In this paper, three distinct techniques are analysed. They are based on the use of i) free-space and ii) non free-space Green's function, and iii) a FDTD approach. All these techniques have been firstly investigated for their 2D version, being used in 2D reconstruction algorithms. However, the scattered field data are collected in a 3D scanner. For assessing the validity of the previous 2D techniques, their results have been compared to both experimentally and 3D-FDTD results.Peer ReviewedPostprint (published version

Interaction of the v-rel protein with an NF-kappa B DNA binding site

The avian reticuloendotheliosis virus T contains within its genome the oncogene rel. The expression of this gene is responsible for the induction of lymphoid tumors in birds. Recently, the rel gene was shown to be related to the p50 DNA binding subunit of the transcription factor complex NF-kappa B. Binding sites for the NF-kappa B complex are found in the enhancer regions of a number of genes, including the immunoglobulin kappa gene and the human immunodeficiency virus long terminal repeat. In this communication we identify an activity from avian reticuloendotheliosis virus T-transformed avian lymphoid cells that binds in an electrophoretic-mobility-shift assay to an NF-kappa B binding site from the kappa enhancer. This activity contains proteins immunologically related to rel, as detected by polyclonal and monoclonal antibodies directed against v-rel. In a DNA affinity precipitation assay using the NF-kappa B site from the human immunodeficiency virus long terminal repeat, v-rel and several other proteins were identified. These data suggest that oncogenic transformation by v-rel is the result of an altered pattern of gene expression

Discussion of “Observation of ground movement with existing pile groups due to tunneling in sand using centrifuge modelling” by Ittichai Boonsiri and Jiro Takemura

This discussion aims to highlight the underlying cause of several aspects of the greenfield settlement data presented by Boonsiri and Takemura (Geotech Geol Eng 33(3):621–640, 2015). The discussion considers, for the geotechnical centrifuge tests that were reported, the effects of the boundary conditions imposed at the model tunnel on resulting settlements. Data obtained using the rigid boundary model tunnel in Boonsiri and Takemura (Geotech Geol Eng 33(3):621–640, 2015) are compared against other available data from tests using a fluid-filled flexible membrane model tunnel. It is demonstrated that the boundary conditions used to simulate tunnel ground loss have an important impact on the settlement mechanism; compared to a fluid-filled flexible membrane, a rigid boundary model tunnel results in wider settlement troughs, which do not vary in shape considerably with changes in relative tunnel depth, and can result in higher ratios between the area of the settlement troughs and the tunnel ground loss. The appropriateness of the different tunnel boundary conditions is also discussed

A platform for multi-point fiber optic base dosimetry

Radiotherapy is in a period of rapid scientific and clinical development and the increasing complexity of modern treatment modalities has also introduced a more comprehensive patient-specific quality assurance programme (QA) to verify an individual patient delivery. Optical fibers offer a solution for in vivo radiotherapy dosimetry with many advantages over currently employed clinical dosimetry systems. A new technology is based on the use of luminescent materials with a plastic optical fiber, acting as light guides, to create a multi-point dosimeter. In this study, two different types of optical fibers with a core diameter of 1mm were used in all the characterization measurements. In both cases the inorganic radiation sensor is based on europium-doped yttrium oxide and emits light slightly above 600nm. In both configurations, the fibers were connected to a small portable reader. Optical fibers were irradiated in a water equivalent slab phantom, at the nominal photon energy of a 6MV clinical accelerator for a fixed dose of 1Gy. Field Output Factors (OF) for photon small beams were measured using the two fibers and a ionization chamber. Several measurements of the signal were performed to test the stability over time and repeatability. The comparison of OF measurements between the two fibers and the ion chamber was performed. In our preliminary measurements optical fibers have been demonstrated to be able to perform accurate radiotherapy dosimetric measurements

Tunnel–framed building interaction: comparison between raft and separate footing foundations

This paper investigates the influence of the foundation configuration (raft or separate footings) on tunnel-soil-framed building interaction using geotechnical centrifuge testing. Tunnelling-induced soil movements and deformation fields, framed building displacements, and structure shear distortions (with associated modification factors) are illustrated. Framed building stiffness and footing bearing capacity are also evaluated experimentally. Results show that the foundation configuration plays an important role in determining the ground response to tunnelling, affecting soil displacement fields as well as the distribution of soil shear and volumetric strains. In particular, foundation settlements and differential horizontal displacements are larger for separate footings compared to raft foundations. The effects of building width, weight, and eccentricity (with respect to the tunnel) on foundation settlements and structural distortions is quantified for separate footings and contrasted against results for raft foundations. The modification factor of the maximum building shear distortion is linked to the relative soil-building shear stiffness; interestingly, for buildings with similar values of relative stiffness, the level of shear distortion within framed buildings is lower for separate footings than rafts

Protein tyrosine phosphatases: the problems of a growing family

Protein tyrosine phosphorylation is now recognized as an important component of the control of many fundamental aspects of cellular function, including growth and differentiation, cell cycle and cytoskeletal integrity. In vivo, the net level of phosphorylation of tyrosyl residues in a target substrate reflects the balance between the competing action of kinases and phosphatases. We are examining physiological roles for protein tyrosine phosphorylation, pursuing the problem from the perspective of the enzymes that catalyze the dephosphorylation reaction, the protein tyrosine phosphatases (PTPases). The PTPases have, until recently, been somewhat neglected relative to the protein tyrosine kinases (PTKs). However, considerable progress has been made in identifying new members of the PTPase family, and it appears that they constitute a novel class of signal transducing molecules that rival the PTKs in their structural diversity and complexity. One of the principal reasons that the study of PTPases has lagged behind that of the..

Tunneling-Induced Deformation of Bare Frame Structures on Sand: Numerical Study of Building Deformations

The paper compares the performance of two Finite Element Method approaches in reproducing the response of bare frame structures to tunneling in dry dense sand. A fully coupled approach, in which the tunnel, frame and soil are accounted for, is compared with a two-stage method incorporating simpler structural and soil models. The two approaches are validated against centrifuge test results of tunneling in sand beneath frames founded on either rafts or separate footings. Both approaches provide good estimates of displacements and distortions experienced by the frames provided that the soil-foundation interface and structural stiffness are correctly accounted for. The numerical models are also employed to extend the range of eccentric configurations investigated with centrifuge tests. The results demonstrate that shear deformations play an important role for all considered buildings, whereas only frames on separate footings are sensitive to horizontal ground movements. Finally, data are synthesized using modification factors and recently proposed relative stiffness terms

Genome-Wide Identification of HrpL-Regulated Genes in the Necrotrophic Phytopathogen Dickeya dadantii 3937

BACKGROUND: Dickeya dadantii is a necrotrophic pathogen causing disease in many plants. Previous studies have demonstrated that the type III secretion system (T3SS) of D. dadantii is required for full virulence. HrpL is an alternative sigma factor that binds to the hrp box promoter sequence of T3SS genes to up-regulate their expression. METHODOLOGY/PRINCIPAL FINDINGS: To explore the inventory of HrpL-regulated genes of D. dadantii 3937 (3937), transcriptome profiles of wild-type 3937 and a hrpL mutant grown in a T3SS-inducing medium were examined. Using a cut-off value of 1.5, significant differential expression was observed in sixty-three genes, which are involved in various cellular functions such as type III secretion, chemotaxis, metabolism, regulation, and stress response. A hidden Markov model (HMM) was used to predict candidate hrp box binding sites in the intergenic regions of 3937, including the promoter regions of HrpL-regulated genes identified in the microarray assay. In contrast to biotrophic phytopathgens such as Pseudomonas syringae, among the HrpL up-regulated genes in 3937 only those within the T3SS were found to contain a hrp box sequence. Moreover, direct binding of purified HrpL protein to the hrp box was demonstrated for hrp box-containing DNA fragments of hrpA and hrpN using the electrophoretic mobility shift assay (EMSA). In this study, a putative T3SS effector DspA/E was also identified as a HrpL-upregulated gene, and shown to be translocated into plant cells in a T3SS-dependent manner. CONCLUSION/SIGNIFICANCES: We provide the genome-wide study of HrpL-regulated genes in a necrotrophic phytopathogen (D. dadantii 3937) through a combination of transcriptomics and bioinformatics, which led to identification of several effectors. Our study indicates the extent of differences for T3SS effector protein inventory requirements between necrotrophic and biotrophic pathogens, and may allow the development of different strategies for disease control for these different groups of pathogens