198 research outputs found
Experimental study on bond performance of GFRP bars in self-compacting steel fiber reinforced concrete
Reinforcing bars made of Glass-Fiber-Reinforced Polymers (GFRP) are more and more common as
internal reinforcement of concrete structures and infrastructures. Since the design of GFRP reinforced concrete
members is often controlled by serviceability limit state criteria (i.e., deflection or crack width control), an
accurate knowledge of the GFRP-concrete bond behavior is needed to formulate sound design equations.
Furthermore, bond laws currently available and widely accepted for conventional steel rebars cannot be
straightforwardly applied for GFRP ones. Hence, an experimental program consisting of 36 pullout bending tests
was carried out to evaluate the bond performance between GFRP bars and steel fiber reinforced self-compacting
concrete (SFRSCC) by analyzing the influence of the following parameters: GFRP bar diameter, surface
characteristics of the GFRP bars, bond length, and SFRSCC cover thickness. Based on the results obtained in
this study, pullout failure was occurred for almost all the specimens. SFRSCC cover thickness and bond length
plaid important role on the ultimate value of bond stress of GFRP bars. Moreover, the GFRP bars with ribbed
and sand-coated surface treatment showed different interfacial bond behaviors.Fundação para a Ciência e a Tecnologia (FCT
Numerical calibration of bond laws for GFRP bars embedded in steel fiber-reinforced self-compacting concrete
An experimental program was carried out at the Laboratory of Structural Division of the Civil
Engineering Department of the University of Minho (LEST-UM) to investigate the bond behaviour of glass
fibre reinforced polymer (GFRP) bars embedded in steel fibre reinforced self-compacting concrete
(SFRSCC) for the development of an innovative structural system. Thirty-six pull-out-bending tests were
executed to assess the influence of the bond length, concrete cover, bar diameter and surface treatment on the
bond of GFRP bars embedded in SFRSCC. This paper reports the results of a numerical study aiming to
identify an accurate GFRP–SFRSCC bond-slip law. Thus, the above mentioned pullout bending tests were
simulated by using a nonlinear finite element (FE) constitutive model available in FEMIX, a FEM based
computer program. The bond-slip relationship adopted for modelling the FE interface that simulates the
interaction between bar and concrete is the key nonlinear aspect considered in the FE analyses, but the
nonlinear behaviour of SFRSCC due to crack initiation and propagation was also simulated. The evaluation
of the values of the relevant parameters defining such a bond-slip relationship was executed by fitting the
force versus loaded end slip responses recorded in the experimental tests. Finally, correlations are proposed
between the parameters identifying the bond-slip relationship and the relevant geometric and mechanical
properties of the tested specimens.Fundação para a Ciência e a Tecnologia (FCT
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The Impact of Sugar Cane–Burning Emissions on the Respiratory System of Children and the Elderly
We analyzed the influence of emissions from burning sugar cane on the respiratory system during almost 1 year in the city of Piracicaba in southeast Brazil. From April 1997 through March 1998, samples of inhalable particles were collected, separated into fine and coarse particulate mode, and analyzed for black carbon and tracer elements. At the same time, we examined daily records of children ( 64 years of age) admitted to the hospital because of respiratory diseases. Generalized linear models were adopted with natural cubic splines to control for season and linear terms to control for weather. Analyses were carried out for the entire period, as well as for burning and nonburning periods. Additional models were built using three factors obtained from factor analysis instead of particles or tracer elements. Increases of 10.2 μg/m3 in particles ≥ 2.5 μm/m3 aerodynamic diameter (PM2.5) and 42.9 μg/m3 in PM10 were associated with increases of 21.4% [95% confidence interval (CI), 4.3–38.5] and 31.03% (95% CI, 1.25–60.21) in child and elderly respiratory hospital admissions, respectively. When we compared periods, the effects during the burning period were much higher than the effects during nonburning period. Elements generated from sugar cane burning (factor 1) were those most associated with both child and elderly respiratory admissions. Our results show the adverse impact of sugar cane burning emissions on the health of the population, reinforcing the need for public efforts to reduce and eventually eliminate this source of air pollution
Entanglement of two-mode Gaussian states: characterization and experimental production and manipulation
A powerful theoretical structure has emerged in recent years on the
characterization and quantification of entanglement in continuous-variable
systems. After reviewing this framework, we will illustrate it with an original
set-up based on a type-II OPO with adjustable mode coupling. Experimental
results allow a direct verification of many theoretical predictions and provide
a sharp insight into the general properties of two-mode Gaussian states and
entanglement resource manipulation
Critical properties of Ising model on Sierpinski fractals. A finite size scaling analysis approach
The present paper focuses on the order-disorder transition of an Ising model
on a self-similar lattice. We present a detailed numerical study, based on the
Monte Carlo method in conjunction with the finite size scaling method, of the
critical properties of the Ising model on some two dimensional deterministic
fractal lattices with different Hausdorff dimensions. Those with finite
ramification order do not display ordered phases at any finite temperature,
whereas the lattices with infinite connectivity show genuine critical behavior.
In particular we considered two Sierpinski carpets constructed using different
generators and characterized by Hausdorff dimensions d_H=log 8/log 3 = 1.8927..
and d_H=log 12/log 4 = 1.7924.., respectively.
The data show in a clear way the existence of an order-disorder transition at
finite temperature in both Sierpinski carpets.
By performing several Monte Carlo simulations at different temperatures and
on lattices of increasing size in conjunction with a finite size scaling
analysis, we were able to determine numerically the critical exponents in each
case and to provide an estimate of their errors.
Finally we considered the hyperscaling relation and found indications that it
holds, if one assumes that the relevant dimension in this case is the Hausdorff
dimension of the lattice.Comment: 21 pages, 7 figures; a new section has been added with results for a
second fractal; there are other minor change
Klebsiella pneumoniae is able to trigger epithelial-mesenchymal transition process in cultured airway epithelial cells
The ability of some bacterial pathogens to activate Epithelial-Mesenchymal Transition normally is a consequence of the persistence of a local chronic inflammatory response or depends on a direct interaction of the pathogens with the host epithelial cells. In this study we monitored the abilities of the K. pneumoniae to activate the expression of genes related to EMT-like processes and the occurrence of phenotypic changes in airway epithelial cells during the early steps of cell infection. We describe changes in the production of intracellular reactive oxygen species and increased HIF-1α mRNA expression in cells exposed to K. pneumoniae infection. We also describe the upregulation of a set of transcription factors implicated in the EMT processes, such as Twist, Snail and ZEB, indicating that the morphological changes of epithelial cells already appreciable after few hours from the K. pneumoniae infection are tightly regulated by the activation of transcriptional pathways, driving epithelial cells to EMT. These effects appear to be effectively counteracted by resveratrol, an antioxidant that is able to exert a sustained scavenging of the intracellular ROS. This is the first report indicating that strains of K. pneumoniae may promote EMT-like programs through direct interaction with epithelial cells without the involvement of inflammatory cells
Reactividad del sistema bifásico tricloroacetonitrilo-CH2Cl2/H2O2 en la epoxidación del aceite de soja
In this work we report on the epoxidation of soybean oil by the trichloroacetonitrile -CH2Cl2/H2O2 byphasic system. The reaction was carried out at room temperature and, most importantly, in non acid conditions which prevent the opening of the oxirane ring. The epoxidized soybean oil was characterized by infrared, 1H and 13C NMR. A maximum conversion of 81 % was achieved in two hours with 86% of selectivity in epoxy groupsEn el presente trabajo informamos sobre la epoxidación de aceite de soja mediante el sistema bifásico tricloroacetonitrilo-CH2Cl2/H2O2. La reacción fue realizada bajo condiciones de temperatura ambiente y, lo más importante, en condición no ácida, lo que evita la apertura del anillo oxirano. El aceite de soja fue caracterizado por infrarrojo y RMN de 1H and 13C. En dos horas se alcanzó una conversión máxima del 81 % obteniéndose una selectividad del 86 % en grupos epóxido
Genetic and epigenetic alterations of cdh1 regulatory regions in hereditary and sporadic gastric cancer
E-cadherin is a key player in gastric cancer (GC) and germline alterations of CDH1, its encoding gene, are responsible for Hereditary Diffuse Gastric Cancer (HDGC) syndrome. This study aimed at elucidating the role of genetic variants and DNA methylation of CDH1 promoter and enhancers in the regulation of gene expression. For this purpose, we analyzed genetic variants of the CDH1 gene through Next-Generation Sequencing (NGS) in a series of GC cell lines (NCI-N87, KATO-III, SNU-1, SNU-5, GK2, AKG, KKP) and the corresponding CDH1 expression levels. By bisulfite genomic sequencing, we analyzed the methylation status of CDH1 regulatory regions in 8 GC cell lines, in a series of 13 sporadic GC tissues and in a group of 20 HDGC CDH1-negative patients and 6 healthy controls. The NGS analysis on CDH1 coding and regulatory regions detected genetic alterations in 3 out of 5 GC cell lines lacking functional E-cadherin. CDH1 regulatory regions showed different methylation patterns in patients and controls, GC cell lines and GC tissues, expressing different E-cadherin levels. Our results showed that alterations in terms of genetic variants and DNA methylation patterns of both promoter and enhancers are associated with CDH1 expression levels and have a role in its regulation.This research and its authors were funded by IRCCS IRST (G.T., C.M., R.D. V.A., M.R., F.R., M.C., S.P., G.M., D.C., P.U.) and by FEDER-Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020–Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT–Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274) (C.S.J., R.B.-M., A.A., C.O.). This work was also financed by the project NORTE-01-0145-FEDER-000029 (CANCER)-supported by Norte Portugal Regional Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)–project POCI-01-0145-FEDER-016390 (CancelStem) and PTDC/BTM-TEC/30164/2017 (3DChroMe), funded by ERDF, POCI and FCT
Blinatumomab vs historical standard therapy of adult relapsed/refractory acute lymphoblastic leukemia
We compared outcomes from a single-arm study of blinatumomab in adult patients with B-precursor Ph-negative relapsed/refractory acute lymphoblastic leukemia (R/R ALL) with a historical data set from Europe and the United States. Estimates of complete remission (CR) and overall survival (OS) were weighted by the frequency distribution of prognostic factors in the blinatumomab trial. Outcomes were also compared between the trial and historical data using propensity score methods. The historical cohort included 694 patients with CR data and 1112 patients with OS data compared with 189 patients with CR and survival data in the blinatumomab trial. The weighted analysis revealed a CR rate of 24% (95% CI: 20-27%) and a median OS of 3.3 months (95% CI: 2.8-3.6) in the historical cohort compared with a CR/CRh rate of 43% (95% CI: 36-50%) and a median OS of 6.1 months (95% CI: 4.2-7.5) in the blinatumomab trial. Propensity score analysis estimated increased odds of CR/CRh (OR=2.68, 95% CI: 1.67-4.31) and improved OS (HR=0.536, 95% CI: 0.394-0.730) with blinatumomab. The analysis demonstrates the application of different study designs and statistical methods to compare novel therapies for R/R ALL with historical data
Ressincronizaçao Cardíaca em Seguimento Tardio: Análise de Preditores de Resposta Clínica
Objetivo: Identificar marcadores de melhora clínica no subgrupo de pacientes com bloqueio completo de ramo esquerdo (BRE) da coorte submetida a ressincronizaçao cardíaca (RC) no InCor-SP do HC-FMUSP. Material e método: Foram analisadas características clínicas e epidemiológicas prospectivas de 121 pacientes com IC e BRE submetidos a RC. O critério de melhora clínica foi a reduçao de pelo menos duas classes funcionais (CF-NYHA) durante acompanhamento mínimo de seis meses. As variáveis analisadas pré e pós RC para comparaçao do comportamento dos grupos foram: CF-NYHA, sexo, idade, drogas, cardiopatia de base, ritmo cardíaco de base, BRE espontâneo X BRE induzido por marcacapasso (troca de sistema ou primeiro implante), diâmetro diastólico final do ventrículo esquerdo (DdVE) e fraçao de ejeçao do ventrículo esquerdo (FEVE - ecocardiograma). A análise estatística foi realizada por meio dos testes de Qui-Quadrado, exato de Fisher e regressao logística de Cox. Resultados: Houve reduçao de duas CF em 36% dos pacientes e de uma CF em 54% (inalterada em 10%). Associaram-se à reduçao significativa da CF (análise univariada) o ritmo sinusal (p=0,023), BRE espontâneo (p=0,035), cardiomiopatia dilatada (CMD) (p=0,03), nao uso de amiodarona (p=0,003) e DdVE (p=0,044). DdVE e CMD foram preditores independentes de melhora clínica (análise múltipla). Conclusoes: 1. A melhora clínica foi maior em pacientes com BRE espontâneo em relaçao ao BRE induzido. 2. As medidas do DdVE e CMD discriminaram subgrupos de resposta clínica satisfatória (seguimento tardio) e foram preditores independentes deste comportamento
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