The combined action of carvacrol and high hydrostatic pressure on Listeria monocytogenes Scott A

Aims: The aim of the study was to investigate the combined antimicrobial action of the plantderived volatile carvacrol and high hydrostatic pressure (HHP). Methods and Results: Combined treatments of carvacrol and HHP have been studied at different temperatures, using exponentially growing cells of Listeria monocytogenes, and showed a synergistic action. The antimicrobial effects were higher at 1°C than at 8 or 20°C. Furthermore, addition of carvacrol to cells exposed to sublethal HHP treatment caused similar reductions in viable numbers as simultaneous treatment with carvacrol and HHP. Synergism was also observed between carvacrol and HHP in semi-skimmed milk that was artifcially contaminated with L. monocytogenes. Conclusions: Carvacrol and HHP act synergistically and the antimicrobial effects of the combined treatment are greater at lower temperatures. Significance and Impact of the Study: The study demonstrates the synergistic antimicrobial effect of essential oils in combination with HHP and indicates the potential of these combined treatments in food processing.

Combined action of S-carvone and mild heat treatment on Listeria monocytogenes Scott A

The combined action of the plant-derived volatile, S-carvone, and mild heat treatment on the food-borne pathogen, Listeria monocytogenes, was evaluated. The viability of exponential phase cultures grown at 8 °C could be reduced by 1·3 log units after exposure to S-carvone (5 mmol l−1) for 30 min at 45 °C, while individual treatment with S-carvone or exposure to 45 °C for 30 min did not result in a loss in viability. Other plant-derived volatiles, namely carvacrol, cinnamaldehyde, thymol and decanal, were also found to reduce the viability of L. monocytogenes in combination with the same mild heat treatment at concentrations of 1·75 mmol l−1, 2·5 mmol l−1, 1·5 mmol l−1 and 2 mmol l−1, respectively. These findings show that essential oil compounds can play an important role in minimally processed foods, and can be used in the concept of Hurdle Technology to reduce the intensity of heat treatment or other individual hurdles.

Stable propagation of solitons with increased energy through the combined action of dispersion management and periodic saturable absorption

It is shown, through numerical simulations, that by using a combination of dispersion management and periodic saturable absorption it is possible to transmit solitonlike pulses with greatly increased energy near to the zero net dispersion wavelength. This system is shown to support the stable propagation of solitons over transoceanic distances for a wide range of input powers.

Stable propagation of solitons with increased energy through the combined action of dispersion management and periodic saturable absorption

It is shown, through numerical simulations, that by using a combination of dispersion management and periodic saturable absorption it is possible to transmit solitonlike pulses with greatly increased energy near to the zero net dispersion wavelength. This system is shown to support the stable propagation of solitons over transoceanic distances for a wide range of input powers.

A combined approach for the assessment of cell viability and cell functionality of human fibrochondrocytes for use in tissue engineering.

Temporo-mandibular joint disc disorders are highly prevalent in adult populations. Autologous chondrocyte implantation is a well-established method for the treatment of several chondral defects. However, very few studies have been carried out using human fibrous chondrocytes from the temporo-mandibular joint (TMJ). One of the main drawbacks associated to chondrocyte cell culture is the possibility that chondrocyte cells kept in culture tend to de-differentiate and to lose cell viability under in in-vitro conditions. In this work, we have isolated human temporo-mandibular joint fibrochondrocytes (TMJF) from human disc and we have used a highly-sensitive technique to determine cell viability, cell proliferation and gene expression of nine consecutive cell passages to determine the most appropriate cell passage for use in tissue engineering and future clinical use. Our results revealed that the most potentially viable and functional cell passages were P5-P6, in which an adequate equilibrium between cell viability and the capability to synthesize all major extracellular matrix components exists. The combined action of pro-apoptotic (TRAF5, PHLDA1) and anti-apoptotic genes (SON, HTT, FAIM2) may explain the differential cell viability levels that we found in this study. These results suggest that TMJF should be used at P5-P6 for cell therapy protocols.

Cohesive-frictional modelling of bond and splitting action of prestressing wire

This work shows a numerical procedure for bond between indented wires and concrete, and the coupled splitting of the concrete. The bond model is an interface, non-associative, plasticity model. It is coupled with a cohesive fracture model for concrete to take into account the splitting of such concrete. The radial component of the prestressing force, increased by Poisson’s effect, may split the surrounding concrete, decreasing the wire confinement and diminishing the bonding. The combined action of the bond and the splitting is studied with the proposed model. The results of the numerical model are compared with the results of a series of tests, such as those which showed splitting induced by the bond between wire and concrete. Tests with different steel indentation depths were performed. The numerical procedure accurately reproduces the experimental records and improves knowledge of this complex process.

Modulation of small leucine-rich proteoglycans (SLRPs) expression in the mouse uterus by estradiol and progesterone

Background: We have previously demonstrated that four members of the family of small leucine-rich-proteoglycans (SLRPs) of the extracellular matrix (ECM), named decorin, biglycan, lumican and fibromodulin, are deeply remodeled in mouse uterine tissues along the estrous cycle and early pregnancy. It is known that the combined action of estrogen (E2) and progesterone (P4) orchestrates the estrous cycle and prepares the endometrium for pregnancy, modulating synthesis, deposition and degradation of various molecules. Indeed, we showed that versican, another proteoglycan of the ECM, is under hormonal control in the uterine tissues. Methods: E2 and/or medroxiprogesterone acetate (MPA) were used to demonstrate, by real time PCR and immunoperoxidase staining, respectively, their effects on mRNA expression and protein deposition of these SLRPs, in the uterine tissues. Results: Decorin and lumican were constitutively expressed and deposited in the ECM in the absence of the ovarian hormones, whereas deposition of biglycan and fibromodulin were abolished from the uterine ECM in the non-treated group. Interestingly, ovariectomy promoted an increase in decorin, lumican and fibromodulin mRNA levels, while biglycan mRNA conspicuously decreased. Hormone replacement with E2 and/or MPA differentially modulates their expression and deposition. Conclusions: The patterns of expression of these SLRPs in the uterine tissues were found to be hormone-dependent and uterine compartment-related. These results reinforce the existence of subpopulations of endometrial fibroblasts, localized into distinct functional uterine compartments, resembling the organization into basal and functional layers of the human endometrium.

Synthesis, characterization, and bactericidal properties of composites based on crosslinked resins containing silver

Two different commercial crosslinked resins (Amberlite GT73 and Amberlite IRC748) were employed for anchoring silver. The -SH and -N(CH2COOH)2 groups, respectively, present on these resins were used for Ag+ chelation from an aqueous solution. The Ag+ ions were reduced with three different reductants: hydrazine, hydroxylamine, and formaldehyde (under an alkaline pH). The produced composites were characterized with thermogravimetry/differential thermogravimetry and scanning electron microscopy combined with a backscattered scanning electron detector. Energy-dispersive X-ray spectroscopy coupled to scanning electron microscopy allowed the observation of submicrometer particles of silver, and chemical microanalysis of emitted X-rays revealed the presence of metal on the internal and external surfaces of the composite microspheres. The amount of incorporated silver was determined by titration. The antibacterial activity of the silver/resin composites was determined toward 10(3)-10(7) cells/mL dilutions of the auxotrophic AB1157 Escherichia coli strain; the networks containing anchored submicrometer silver particles were completely bactericidal within a few minutes because of the combined action of silver and functional groups of the resins. (c) 2007 Wiley Periodicals, Inc.

Effects on mitochondria of mitochondria-induced nitric oxide release from a ruthenium nitrosyl complex

The ruthenium nitrosyl complex trans-[Ru(NO)(NH(3))(4)(py)](PF(6))(3) (pyNO), a nitric oxide (NO) donor, was studied in regard to the release of NO and its impact both on isolated mitochondria and HepG2 cells. In isolated mitochondria, NO release from pyNO was concomitant with NAD(P)H oxidation and, in the 25-100 mu M range, it resulted in dissipation of mitochondrial membrane potential, inhibition of state 3 respiration, ATP depletion and reactive oxygen species (ROS) generation. In the presence of Ca(2+), mitochondrial permeability transition (MPT), an unspecific membrane permeabilization involved in cell necrosis and some types of apoptosis, was elicited. As demonstrated by externalization of phosphatidylserine and activation of caspase-9 and caspase-3, pyNO (50-100 mu M) induced HepG2 cell death, mainly by apoptosis. The combined action of the NO itself, the peroxynitrite yielded by NO in the presence of reactive oxygen species (ROS) and the oxidative stress generated by the NAD(P)H oxidation is proposed to be involved in cell death by pyNO, both via respiratory chain inhibition and ROS levels increase, or even via MPT, if Ca(2+) is present. (c) 2008 Elsevier Inc. All rights reserved.

Melatonin and dehydroepiandrosterone combination: does this treatment exert a synergistic effect during experimental Trypanosoma cruzi infection?

Previous studies showed that melatonin or dehydroepiandrosterone (DHEA) enhances the immune response against parasitic pathogens. The present study investigated the in vitro activity of melatonin combined with DHEA in a period of 24 hr during the course of in vivo T. cruzi infection. The in vitro activity of melatonin or DHEA alone, as well as together, were tested for the trypomastigote forms (doses ranging from 0.5 to 128 mu m). In vitro, neither melatonin nor DHEA alone had any activity against trypomastigote forms, although when the highest concentration of combined melatonin and DHEA was used, it was active against the trypomastigote forms of the parasite. However, for this concentration, a quite toxicity on peritoneal macrophages was observed. For in vivo evaluation, male Wistar rats were infected with the Y strain of T. cruzi. They were orally treated with 10 mg/kg body weight/day of melatonin and subcutaneously with 40 mg/kg body weight/day of DHEA. Treatment with melatonin, DHEA and the association showed a significant reduction in the number of blood trypomastigotes during the acute phase of infection as compared to untreated animals (P < 0.05). A significant increase in the number of macrophages and nitric oxide (NO) concentrations were observed during the peak of parasitaemia with melatonin alone or combined with DHEA. However, with DHEA alone the highest concentration of NO was observed (P < 0.05). Moreover, DHEA treatment increased TNF-alpha levels during the infection (P < 0.05). These results show that melatonin, DHEA or the combination of both reduces parasitemia during the acute phase of infection. The combined action of both molecules did not exert a synergic action on the host`s ability to fight infection, and it seems that among all treatments DHEA induces a more efficient immune response.

Chk1 regulates the S phase checkpoint by coupling the physiological turnover and ionizing radiation-induced accelerated proteolysis of Cdc25A

Chk1 kinase coordinates cell cycle progression and preserves genome integrity. Here, we show that chemical or genetic ablation of human Chk1 triggered supraphysiological accumulation of the S phase-promoting Cdc25A phosphatase, prevented ionizing radiation (IR)-induced degradation of Cdc25A, and caused radioresistant DNA synthesis (RDS). The basal turnover of Cdc25A operating in unperturbed S phase required Chk1-dependent phosphorylation of serines 123, 178, 278, and 292. IR-induced acceleration of Cdc25A proteolysis correlated with increased phosphate incorporation into these residues generated by a combined action of Chk1 and Chk2 kinases. Finally, phosphorylation of Chk1 by ATM was required to fully accelerate the IR-induced degradation of Cdc25A. Our results provide evidence that the mammalian S phase checkpoint functions via amplification of physiologically operating, Chk1-dependent mechanisms.

Postbuckling of piezoelectric FGM plates subject to thermo-electro-mechanical loading

In this paper, we examine the postbuckling behavior of functionally graded material FGM rectangular plates that are integrated with surface-bonded piezoelectric actuators and are subjected to the combined action of uniform temperature change, in-plane forces, and constant applied actuator voltage. A Galerkin-differential quadrature iteration algorithm is proposed for solution of the non-linear partial differential governing equations. To account for the transverse shear strains, the Reddy higher-order shear deformation plate theory is employed. The bifurcation-type thermo-mechanical buckling of fully clamped plates, and the postbuckling behavior of plates with more general boundary conditions subject to various thermo-electro-mechanical loads, are discussed in detail. Parametric studies are also undertaken, and show the effects of applied actuator voltage, in-plane forces, volume fraction exponents, temperature change, and the character of boundary conditions on the buckling and postbuckling characteristics of the plates. (C) 2003 Elsevier Science Ltd. All rights reserved.

Epidemiologia da insónia em adolescentes : do diagnóstico de situação à intervenção

RESUMO - Introdução: Os problemas do sono, designadamente a insónia, os sintomas de insónia, os padrões de sono inadequados e a sonolência diurna, são frequentes na adolescência. Estes problemas estão frequentemente associados a múltiplos fatores, entre os quais estilos de vida e fatores ambientais, e apresentam consequências significativas na vida do adolescente e posteriormente na idade adulta. O sono e as suas perturbações deveriam constituir uma preocupação para os profissionais da saúde e da educação com o objetivo de tornar os hábitos de sono saudáveis num estilo de vida - com benefícios calculáveis como os associados a outros estilos de vida saudáveis (alimentação e exercício físico). Em Portugal, os estudos sobre problemas do sono em adolescentes são escassos, bem como as intervenções individuais e comunitárias no âmbito da higiene do sono. Os objetivos desta investigação foram estimar a prevalência de insónia e de sintomas de insónia em adolescentes, identificar fatores de risco e protetores dos sintomas de insónia, analisar as repercussões dos sintomas de insónia, caracterizar os padrões de sono dos adolescentes do distrito de Viseu e elaborar uma proposta de intervenção destinada à promoção da higiene do sono adaptada às características dos adolescentes do distrito de Viseu. Métodos: Realizou-se um estudo transversal onde se avaliaram alunos de vinte e seis escolas públicas do terceiro ciclo e secundário do distrito de Viseu, durante ano letivo 2011/2012. A recolha dos dados foi efetuada através de um questionário autoaplicado e respondido pelos alunos em sala de aula. Foram considerados elegíveis para participar no estudo todos os alunos que frequentassem entre o 7.º e o 12.º ano de escolaridade e tivessem idades entre os 12 e os 18 anos. Dos 9237 questionários distribuídos recolheu-se 7581 (82,1%). Foram excluídos da análise os questionários relativos a adolescentes com idade inferior a 12 ou superior a 18 anos e os questionários devolvidos por preencher. A amostra global foi constituída por 6919 adolescentes, sendo 3668 (53,2%) do sexo feminino. A insónia foi definida com base na presença, no mês prévio, dos sintomas de insónia definidos nos critérios do DSM-IV (dificuldade em adormecer, dificuldade em manter o sono, acordar muito cedo e ter dificuldade em voltar a adormecer e sono não reparador) com uma frequência de pelo menos três vezes por semana e associados a consequências no dia-a-dia. A qualidade de vida foi avaliada com recurso à escala de qualidade de vida SF-36; a sintomatologia depressiva através do Inventário de Depressão de Beck para adolescentes (BDI-II) e a sonolência diurna utilizando a Escala de Sonolência de Epworth (ESE). Para responder ao último objetivo foi elaborada uma proposta de intervenção individual e comunitária no âmbito da higiene do sono. A proposta resulta da evidência científica, dos resultados da presente investigação e de reuniões com profissionais da saúde e da educação. Resultados: No total da amostra, a prevalência de insónia foi de 8,3% e de sintomas de insónia foi de 21,4%. A prevalência de insónia foi superior no sexo feminino (10,1% vs. 5,9%; p<0,001) assim como a prevalência de sintomas de insónia (25,6% vs. 15,8%; p<0,001). Individualmente, todos os sintomas foram mais prevalentes no sexo feminino, sendo a diferença estatisticamente significativa (p<0,001). Em média os adolescentes dormiam, durante a semana, 8:04±1:13 horas. A prevalência de sono insuficiente (< 8 horas) foi de 29%. Apenas 6,4% dos adolescentes indicaram que se deitavam todas as noites à mesma hora. A prevalência de sintomatologia depressiva foi de 20,9% (26,0% nas raparigas e 15,1% nos rapazes, p<0,001). A prevalência de sonolência diurna foi de 33,1%, apresentando o sexo feminino um risco superior (OR=1,40; IC95%: 1,27-1,55). A prevalência de sintomatologia depressiva e de sonolência diurna foi superior entre os adolescentes com sintomas de insónia (48,2% vs. 18,8%, p<0,001 e 42,4% vs. 33,0%, p<0,001, respetivamente). Os adolescentes com sintomas de insónia apresentavam igualmente pior qualidade de vida. Em relação a outras repercussões no dia-a-dia, foram os adolescentes com sintomas de insónia que referiam mais vezes sentir dificuldade em levantar-se de manhã, acordar com cefaleias, acordar cansado e recorrer a medicação para dormir. Nos rapazes os sintomas de insónia associaram-se com o IMC. Após o ajustamento para o sexo e idade com recurso à regressão logística verificou-se uma associação entre sintomas de insónia e sexo feminino [OR ajustado(idade)= 1,82; IC95%: 1,56-2,13], idade ≥16 anos [OR ajustado(sexo)= 1,17; IC95%: 1,01-1,35], residência urbana (OR ajustado= 1,30; IC95%: 1,04-1,63), consumo de café (OR ajustado= 1,40; IC95%: 1,20-1,63), consumo de bebidas alcoólicas (OR ajustado= 1,21; IC95%: 1,03-1,41) e sintomatologia depressiva (OR ajustado= 3,59; IC95%: 3,04-4,24). Quanto à escolaridade dos pais, verificou-se uma redução do risco com o aumento da escolaridade dos pais (5º-6º ano OR ajustado= 0,82; IC95%: 0,64- 1,05; 7º-12º ano OR ajustado= 0,77; IC95%: 0,61-0,97; >12º ano OR ajustado= 0,64; IC95%: 0,47-0,87). Após uma análise multivariada, o modelo preditivo para a ocorrência de sintomas de insónia incluiu as variáveis sexo feminino, viver em meio urbano, consumir café e apresentar sintomatologia depressiva. Este modelo apresenta uma especificidade de 84,2% e uma sensibilidade de 63,6%. O sono insuficiente associou-se, após ajuste para o sexo e idade, com o ano de escolaridade, estado civil dos pais, determinados estilos de vida (consumo de café, tabagismo, consumo de álcool, consumo de outras drogas, sair à noite, presença de TV no quarto e número de horas despendido a ver televisão e no computador), latência do sono, sesta > 30 minutos, horários de sono irregulares e com a toma de medicamentos para dormir. Os resultados deste estudo constituem um diagnóstico de situação relativamente aos problemas de sono em adolescentes no distrito de Viseu. Tendo por base os princípios da Carta de Ottawa relativamente à promoção da saúde, a proposta elaborada visa a implementação de estratégias de prevenção agrupadas em intervenções individuais, comunitárias e sobre os planos curriculares. As intervenções baseiam-se na utilização das tecnologias da informação e comunicação, no contexto da nova arquitetura na esfera pública da saúde conducente aos sistemas personalizados de informação em saúde (SPIS). Conclusões: Registou-se uma elevada prevalência de insónia e sintomas de insónia entre os adolescentes do distrito de Viseu, superior no sexo feminino. A presença de sintomas de insónia esteve associada, sobretudo, a determinados estilos de vida e à ausência de higiene do sono. Os problemas de sono em adolescentes, devido à sua frequência e repercussões, devem constituir uma preocupação em termos de saúde pública e constituir uma prioridade nas estratégias de educação para a saúde. Os 9 princípios da intervenção delineada visam uma abordagem preventiva de problemas de sono - através da ação conjunta de profissionais da saúde e da educação, de elementos da comunidade e com o indispensável envolvimento dos adolescentes e da família -, procurando instituir os hábitos de sono saudáveis como um estilo de vida.

Carbonation front progress in mortars containing fly ash considering the presence of chloride ions

The incorporation of fly ash (FA) in cementitious matrices have been frequently used in order to make the matrix more resistant to the action of chlorides. On the other hand, it is known that Ca (OH)2 existing in the matrix is partially consumed by the pozzolanic reactions, which facilitates the advancement of carbonation. Given that the combined action between carbonation and chloride penetration is a fact little known, we speculate about the behaviour of the matrix in this context. This study investigates the influence of the presence of chlorides on the carbonation in mortars with FA. Samples with 0% and 40% replacement of cement CEM I 42.5 R for FA were molded with water/binder 0.56 and 0.52 respectively. After 90 days of curing the specimens were subjected to cycles of immersion/drying for 56 days. Half of the samples was subjected to the following cycle: two days in a solution containing NaCl (concentration equal to 3.5 %); 12 days in the carbonation chamber (4% of CO2). The other half was: two days in water; 12 days in the carbonation chamber. Then, the development of carbonation was evaluated. The results indicate that the presence of chlorides influences the carbonation. The specimens submitted to the exclusive action of CO2 showed a greater depth of carbonation compared to that presented by the specimens subjected to combined action. This may be related to changes in properties of the matrix which may lead to further refinement of the pores and related to the presence of the salt that can lead to partial filling of the pores and the increase in moisture content.