DNA-psoralen: single-molecule experiments and first principles calculations

The authors measure the persistence and contour lengths of DNA-psoralen complexes, as a function of psoralen concentration, for intercalated and crosslinked complexes. In both cases, the persistence length monotonically increases until a certain critical concentration is reached, above which it abruptly decreases and remains approximately constant. The contour length of the complexes exhibits no such discontinuous behavior. By fitting the relative increase of the contour length to the neighbor exclusion model, we obtain the exclusion number and the intrinsic intercalating constant of the psoralen-DNA interaction. Ab initio calculations are employed in order to provide an atomistic picture of these experimental findings.Comment: 9 pages, 4 figures in re-print format 3 pages, 4 figures in the published versio

Composição de betão de resistência melhorada ao fogo para aduelas de túneis : parte I

Relatório técnico 05-DEC/E-32Para a obtenção de um betão de ductilidade elevada e resistência melhorada ao fogo para aduelas de túneis, optou-se, entre outros, pela utilização de dois tipos de fibras. Um primeiro tipo de fibra, não metálica, que apresenta reduzido grau de polimerização e derrete na presença de temperaturas elevadas. Sob a acção do fogo, o desaparecimento desta fibra irá criar uma rede de micro canais que permite a saída do vapor de água do interior do betão. A inclusão deste tipo de fibra também reduz a propagação de fendas durante a fase de retracção plástica do betão. O outro tipo de fibra, metálica, tem o propósito de garantir o nível de ductilidade que se pretende para o betão, bem como reduzir a quantidade de armadura convencional a colocar nos elementos estruturais. O presente relatório começa com uma breve síntese do estado do conhecimento no âmbito de: incêndios em túneis, aspectos acerca do dimensionamento de aduelas para túneis, nomeadamente a inclusão de fibras metálicas e o comportamento do betão sob temperaturas elevadas (alterações das suas propriedades, cenários de fogo normalizados, classificação dos materiais e inspecção e avaliação de estruturas afectadas). Segue-se uma secção onde são reportados os ensaios preliminares efectuados com vista à selecção do tipo e dosagem de fibra não metálica a utilizar, bem como o tempo necessário para a estabilização da resistência residual do betão com o tempo após a exposição à simulação do efeito do fogo.To develop a high ductility concrete of enhanced fire resistance, two distinct types of fibers were used. The first one is a non-metallic fiber, with low degree of polymerization, that sublimes in the presence of high temperatures. Under the action of fire, these fibers create a network of micro channels for the escape of the water vapor. These fibers have also the purpose of decreasing the crack formation and crack propagation during the concrete plastic shrinkage phase. The other type of fibers, is made by steel, and has the purpose of providing high ductility to the concrete postcracking behaviour, as well as of replacing, totally of partially, conventional reinforcement applied in pre-casting concrete tunnel segments. A brief state-of-the-art is presented in the following topics: fire in tunnels; design of tunnel segments; the use of metallic fibers in this type of structural elements; concrete behavior under high temperatures (how material properties are affected, fire scenarios, fire classification for materials and inspection and evaluation of affected structures). A section of this document is dedicated to the description of the preliminary tests carried out to select a non-metallic fiber type and the content of this fiber. The period of time for the stabilization of the concrete compressive residual strength was also assessed

Factores De Riesgo Para Incontinencia Urinaria En El Puerperio

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Fiber reinforced concrete of enhanced fire resistance for tunnel segments

In the last decades, technical and scientific efforts have been done to increase the concrete strength, based on the assumption that more economic, lightweight, durable and good looking structures can be built. This strength enhancement, however, has been obtained by increasing the compactness of the concrete internal structure, resulting concretes with a void percentage much lower than the values observed in concretes of current strength classes. Research and fire accidents have shown that the concrete failure of structures exposed to fire is as explosive as high is the concrete strength class, since the concrete brittleness increases with the concrete compressive strength. In the present work a fiber reinforced concrete of enhanced fire resistance was developed and its properties are characterized by experimental research. This concrete is intended to have enough resistance for the most structural engineering applications, while the performance of the fibrous reinforcement system was evaluated in terms of verifying its possibilities for replacing, partially or totally, conventional reinforcement used in concrete precast tunnel segments.The authors wish to acknowledge the support provided by the Portuguese Science and Technology Foundation (FCT) by means of the project POCTI/ECM/57518/2004 “FICOFIRE - High performance fiber reinforced concrete of enhanced fire resistance”, as well as the support of Spie Batignolles Company

FRCcalc - software for design of fiber reinforced concrete elements according to MC2010 recommendations

A new software, denominated FRCcalc, was developed for the analysis and design of fiber reinforced concrete (FRC) members based on the recommendations and design guidelines of MC2010. The software is guided for the analysis of FRC cross-sections with and without conventional steel reinforcements, submitted to bending and shear, in order to assess the ultimate and serviceability limit state safety verifications of structural members. A main feature of the software is the possibility to run a comparative analysis between FRC and reinforced concrete (RC) cross-sections from the technical aspects. Two examples of the analysis of FRC and RC cross-sections using FRCcalc are presented, having been explored the use of fiber reinforcement in members for increased structural performance and as a total or partial replacement of conventional steel reinforcement. Additionally, in order to appraise FRCcalc accuracy to evaluate the flexural response of FRC and RC cross-sections, a comparison with the results obtained with DOCROS software is presented, being DOCROS based on a layered model capable of attributing to each layer an aimed constitutive model, therefore adequate to predict the moment-curvature of cross sections composed of several types of cement, metallic and polymer materials.The first Author would like to acknowledge the grant SFRH/BDE/96381/2013 co-funded by CiviTest - Pesquisa de Novos Materiais para a Engenharia Civil, Lda. and by FCT - Portuguese Foundation for Science and Technology. The authors also acknowledge the support provided by the FCT project PTDC/ECM-EST/2635/2014

A step towards personalized medicine: establishment of a pharmacogenomics profile of response to BCG intravesical immunotherapy in bladder cancer

The most effective adjuvant therapy of non-muscle invasive bladder cancer (NMIBC) during the last 35 years has been the intravesical instillation with Bacillus Calmette-Guerin (BCG). However, despite its efficacy, approximately 30% of the patients present treatment failure and tumor may progress.info:eu-repo/semantics/publishedVersio

Flow injection analysis using carbon film resistor electrodes for amperometric determination of ambroxol

Flow injection analysis (FIA) using a carbon film sensor for amperometric detection was explored for ambroxol analysis in pharmaceutical formulations. The specially designed flow cell designed in the lab generated sharp and reproducible current peaks, with a wide linear dynamic range from 5 × 10-7 to 3.5 × 10-4 mol L-1, in 0.1 mol L-1 sulfuric acid electrolyte, as well as high sensitivity, 0.110 A mol-1 L cm-2 at the optimized flow rate. A detection limit of 7.6 × 10-8 mol L-1 and a sampling frequency of 50 determinations per hour were achieved, employing injected volumes of 100 [mu]L and a flow rate of 2.0 mL min-1. The repeatability, expressed as R.S.D. for successive and alternated injections of 6.0 × 10-6 and 6.0 × 10-5 mol L-1 ambroxol solutions, was 3.0 and 1.5%, respectively, without any noticeable memory effect between injections. The proposed method was applied to the analysis of ambroxol in pharmaceutical samples and the results obtained were compared with UV spectrophotometric and acid-base titrimetric methods. Good agreement between the results utilizing the three methods and the labeled values was achieved, corroborating the good performance of the proposed electrochemical methodology for ambroxol analysis.http://www.sciencedirect.com/science/article/B6THP-4RW434G-1/1/d40a3f00a2eaccb84817b064f601d0f

Steel fibres for the shear resistance of high strength concrete beams

Available research on the use of steel fibres to increase the shear resistance of concrete structures shows that the effectiveness of this type of reinforcement increases with the increase of the concrete compressive strength, as long as the fibre rupture is avoided. Experimental research has also indicated that the effectiveness of the fibre reinforcement for the shear resistance is more pronounced in shallow beams than in deep beams. In terms of analytical research, some models have been proposed and, recently, RILEM TC 162 TDF recommended an analytical approach for the prediction of the fibre reinforcement contribution in terms of shear resistance of concrete beams. The present work has the purpose to contribute for this topic, discussing the performance of RILEM TC 162 TDF approach, by using the results obtained in an experimental program composed of three point bending tests with shallow beams of high strength concrete (HSC). Six different HSC compositions were developed, varying the dosage of steel fibres (0, 60 and 75 kg/m3) and concrete strength class. The experimental program also included tests to characterize the flexural behaviour of the developed high strength steel fibre reinforced concrete (HSSFRC). Using the force-deflection relationships obtained in the three point-notched beam bending tests, and performing an inverse analysis, the values of the fracture mode I parameters of the HSSFRC were determined. These values were used on the numerical simulation of the tests carried out with HSSFRC beams failing in shear, under the framework of the material nonlinear finite element analysis, in order to evince the influence of using a softening constitutive law for modeling the crack shear sliding. In the present work, the experimental program and the numerical research are described, and the main results are presented and discussed.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/ECM/57518/2004 “FICOFIRE : High performance fiber reinforced concrete of enhanced fire resistance