Study of alkaline hydrothermal activation of belite cements by thermal analysis

The effect of alkaline hydrothermal activation of class-C fly ash belite cement was studied using thermal analysis (TG/DTG) by determining the increase in the combined water during a period of hydration of 180 days. The results were compared with those obtained for a belite cement hydrothermally activated in water. The two belite cements were fabricated via the hydrothermal-calcination route of class-C fly ash in 1 M NaOH solution (FABC-2-N) or demineralised water (FABC-2-W). From the results, the effect of the alkaline hydrothermal activation of belite cement (FABC-2-N) was clearly differentiated, mainly at early ages of hydration, for which the increase in the combined water was markedly higher than that of the belite cement that was hydrothermally activated in water. Important direct quantitative correlations were obtained among physicochemical parameters, such as the combined water, the BET surface area, the volume of nano-pores, and macro structural engineering properties such as the compressive mechanical strength

Quantitative study of hydration of C3S and C2S by thermal analysis. Evolution and composition of C-S-H gels formed

This research is part of a European project (namely, CODICE project), main objective of which is modelling, at a multi-scale, the evolution of the mechanical performance of non-degraded and degraded cementitious matrices. For that, a series of experiments were planned with pure synthetic tri-calcium silicate (C3S) and bi-calcium silicate (C2S) (main components of the Portland cement clinker) to obtain different calcium–silicate–hydrate (C–S–H) gel structures during their hydration. The characterization of those C–S–H gels and matrices will provide experimental parameters for the validation of the multi-scale modelling scheme proposed. In this article, a quantitative method, based on thermal analyses, has been used for the determination of the chemical composition of the C–S–H gel together with the degree of hydration and quantitative evolution of all the components of the pastes. Besides, the microstructure and type of silicate tetrahedron and mean chain length (MCL) were studied by scanning electron microscopy (SEM) and 29Si magic-angle-spinning (MAS) NMR, respectively. The main results showed that the chemical compositions for the C–S–H gels have a CaO/SiO2 M ratio almost constant of 1.7 for both C3S and C2S compounds. Small differences were found in the gel water content: the H2O/SiO2 M ratio ranged from 2.9 ± 0.2 to 2.6 ± 0.2 for the C3S (decrease) and from 2.4 ± 0.2 to 3.2 ± 0.2 for the C2S (increase). The MCL values of the C–S–H gels, determined from 29Si MAS NMR, were 3.5 and 4 silicate tetrahedron, for the hydrated C3S and C2S, respectively, remaining almost constant at all hydration periods

Validação brasileira do Instrumento de Qualidade de Vida/espiritualidade, religião e crenças pessoais

OBJETIVO: Analisar propriedades psicométricas do Instrumento de Qualidade de Vida da Organização Mundial da Saúde - Módulo Espiritualidade, Religiosidade e Crenças Pessoais (WHOQOL-SRPB). MÉTODOS: O WHOQOL-SRPB, a Escala de Coping Religioso/Espiritual Abreviada (CRE-Breve), o WHOQOL-Breve e o BDI foram consecutivamente aplicados em amostra de conveniência de 404 pacientes e funcionários de hospital universitário e funcionários de universidade, em Porto Alegre, RS, entre 2006 e 2009. A amostra foi estratificada por sexo, idade, estado de saúde e religião/crença. O reteste dos dois primeiros instrumentos foi realizado com 54 participantes. Análises fatoriais exploratórias do WHOQOL-SRPB pelo método dos componentes principais foram realizadas sem delimitar o número de fatores, solicitando oito fatores e em conjunto com os itens do WHOQOL-Breve. RESULTADOS: O WHOQOL-SRPB em português brasileiro (Domínio SRPB-Geral) apresentou validade de construto, com validade discriminativa entre crentes de não-crentes (t = 7,40; p = 0,0001); validade relacionada ao critério concorrente, discriminando deprimidos de não-deprimidos (t = 5,03; p = 0,0001); validade convergente com o WHOQOL-Breve (com físico r = 0,18; psicológico r = 0,46; social r = 0,35; ambiental r = 0,29; global r = 0,23; p = 0,0001) e com o Domínio SRPB do WHOQOL-100 (r = 0,78; p = 0,0001); e validade convergente/discriminante com a Escala CRE-Breve (com CREpositivo r = 0,64; p = 0,0001/CREnegativo r = -0,03; p = 0,554). Observou-se excelente fidedignidade teste-reteste (t = 0,74; p = 0,463) e consistência interna (α = 0,96; correlação intrafatorial 0,87 > r > 0,60, p = 0,0001). As análises fatoriais exploratórias realizadas corroboraram a estrutura de oito fatores do estudo multicêntrico do WHOQOL-SRPB. CONCLUSÕES: O WHOQOL-SRPB em português brasileiro apresentou boas qualidades psicométricas e uso válido e fidedigno para uso no Brasil. Sugerem-se novos estudos com populações específicas, como diferentes religiões, grupos culturais e/ou doenças.OBJETIVO: Analizar propiedades psicométricas del Instrumento de Calidad de Vida de la OMS - Módulo Espiritualidad, Religiosidad y Creencias Personales (WHOQOL-SRPB). MÉTODOS: El WHOQOL-SRPB, la Escala de Coping Religioso/Espiritual Abreviada (CRE-Breve), el WHOQOL-Breve y el BDI fueron consecutivamente aplicados en muestra de conveniencia de 404 pacientes y funcionarios de hospital universitario y funcionarios de universidad, en Porto Alegre, Sur de Brasil, entre 2006 y 2009. La muestra fue estratificada por sexo, edad, estado de salud y religión/creencia. La reevaluación de los dos primeros instrumentos fue realizada por 54 participantes. Análisis factoriales exploratorias del WHOQOL-SRPB por el método de los componentes principales fueron realizadas, sin delimitar el número de factores, solicitando ocho factores y en conjunto con los itens del WHOQOL-Breve. RESULTADOS: El WHOQOL-SRPB en portugués-brasileño (Dominio SRPB-General) presentó validez de constructo, con validez discriminativa entre creyentes de no creyentes (t=7,40; p=0,0001); validez relacionada con el criterio concurrente, discriminando deprimidos de no deprimidos (t=5,03; p=0,0001); validez convergente con el WHOQOL-Breve (con físico r=0,18; psicológico r=0,46; social r=0,35; ambiental r=0,29; global r=0,23; p=0,0001) y con el Dominio-SRPB del WHOQOL-100 (r=0,78; p=0,0001); y validez convergente/discriminante con la Escala CRE-Breve (con CRE positivo r=0,64; p=0,0001/CRE negativo r=-0,03; p=0,554). Se observó excelente fidedignidad test-retest (t=0,74; p=0,463) y consistencia interna (α=0,96; correlación intrafactorial 0,87>r>0,60, p=0,0001). Los análisis factoriales exploratorios realizados corroboran la estructura de ocho factores de estudio multicéntrico del WHOQOL-SRPB. CONCLUSIONES: El WHOQOL-SRPB en portugués-brasileño presentó buenas cualidades psicométricas, siendo válido y fidedigno para uso en Brasil. Se sugieren nuevos estudios con poblaciones específicas, como diferentes religiones, grupos culturales y/o enfermedades.OBJECTIVE: To analyze the psychometric properties of the World Health Organization's Quality of Life Instrument - Spirituality, Religion and Personal Beliefs module (WHOQOL-SRPB). METHODS: The WHOQOL-SRPB, the Brief Spiritual/Religious Coping Scale (Brief-SRCOPE Scale), the WHOQOL-BREF and the Beck Depression Inventory (BDI) were consecutively applied in a convenience sample of 404 patients and workers of a university hospital and workers of a university, in the city of Porto Alegre, Southern Brazil, between 2006 and 2009. The sample was stratified by sex, age, health status and religion/belief. The retest of the two first instruments was conducted with 54 participants. Exploratory factorial analyses of the WHOQOL-SRPB with the method of main components were performed, without limiting the number of factors, and requiring eight factors concomitantly with the WHOQOL-BREF items. RESULTS: The Brazilian Portuguese version of the WHOQOL-SRPB (General SRPB-Domain) showed construct validity, with a discriminatory validity between believers and non-believers (t = 7.40; p = 0.0001); concurrent criterion-related validity, distinguishing depressed individuals from non-depressed ones (t = 5.03; p = 0.0001); convergent validity with the WHOQOL-BREF (physical r = 0.18; psychological r = 0.46; social r = 0.35; environmental r = 0.29; global r = 0.23; p = 0.0001) and with the SRPB-Domain of the WHOQOL-100 (r = 0.78; p = 0.0001); and convergent/discriminatory validity with the brief SRCOPE Scale (with positive SRCOPE r = 0.64; p = 0.0001/negative SRCOPE r = -0.03; p = 0.554). Excellent test-retest reliability (t = 0.74; p = 0.463) and internal consistency (α = 0.96; intrafactorial correlation 0.87 > r > 0.60; p = 0.0001) were observed. The exploratory factorial analyses performed corroborated the eight-factor structure of the WHOQOL-SRPB multicenter study. CONCLUSIONS: The Brazilian Portuguese version of the WHOQOL-SRPB showed good psychometric qualities and use valid and reliable in Brazil. It is suggested that new studies be conducted with specific populations, such as different religions, cultural groups and/or diseases

Comparison of methods for the detection of biofilm production in coagulase-negative staphylococci

<p>Abstract</p> <p>Background</p> <p>The ability of biofilm formation seems to play an essential role in the virulence of coagulase-negative staphylococci (CNS). The most clearly characterized component of staphylococcal biofilms is the polysaccharide intercellular adhesin (PIA) encoded by the <it>icaADBC </it>operon. Biofilm production was studied in 80 coagulase-negative staphylococci (CNS) strains isolated from clinical specimens of newborns with infection hospitalized at the Neonatal Unit of the University Hospital, Faculty of Medicine of Botucatu, and in 20 isolates obtained from the nares of healthy individuals without signs of infection. The objective was to compare three phenotypic methods with the detection of the <it>icaA</it>, <it>icaD </it>and <it>icaC </it>genes by PCR.</p> <p>Findings</p> <p>Among the 100 CNS isolates studied, 82% tested positive by PCR, 82% by the tube test, 81% by the TCP assay, and 73% by the CRA method. Using PCR as a reference, the tube test showed the best correlation with detection of the <it>ica </it>genes, presenting high sensitivity and specificity.</p> <p>Conclusions</p> <p>The tube adherence test can be indicated for the routine detection of biofilm production in CNS because of its easy application and low cost and because it guarantees reliable results with excellent sensitivity and specificity.</p

Inhibition of HIV virus by neutralizing Vhh attached to dual functional liposomes encapsulating dapivirine

Although highly active antiretroviral therapy (HAART) has greatly improved the life expectancy of HIV/AIDS patients, the treatment is not curative. It is a global challenge which fosters an urgent need to develop an effective drug or neutralizing antibody delivery approach for the prevention and treatment of this disease. Due to the low density of envelope spikes with restricted mobility present on the surface of HIV virus, which limit the antibody potency and allow virus mutation and escape from the immune system, it is important for a neutralizing antibody to form bivalent or multivalent bonds with the virus. Liposome constructs could fulfil this need due to the flexible mobility of the membrane with its attached antibodies and the capacity for drug encapsulation. In this study, we evaluated the neutralization activity of a range of liposome formulations in different sizes coated with anti-gp120 llama antibody fragments (Vhhs) conjugated via either non-covalent metal chelation or a covalent linkage. The non-covalent construct demonstrated identical binding affinity to HIV-1 envelope glycoprotein gp120 and neutralizing ability for HIV virus as free Vhh. Although covalently linked Vhh showed significant binding affinity to gp120, it unexpectedly had a lower neutralization potency. This may be due to the comparability in size of the viral and liposome particles restricting the number which can be bound to the liposome surface so involving only a fraction of the antibodies, whereas non-covalently attached antibodies dissociate from the surface after acting with gp120 and free the remainder to bind further viruses. Covalently conjugated Vhh might also trigger the cellular uptake of a liposome-virion complex. To explore the possible ability of the antibody-coated liposomes to have a further function, we encapsulated the hydrophobic antiviral drug dapivirine into both of the non-covalently and covalently conjugated liposome formulations, both of which revealed high efficacy in reducing viral replication in vitro. Thus, dual function liposomes may lead to a novel strategy for the prophylaxis of HIV/AIDS by combining the neutralizing activity of Vhh with antiviral effects of high drug concentrations

Cardiac-Oxidized Antigens Are Targets of Immune Recognition by Antibodies and Potential Molecular Determinants in Chagas Disease Pathogenesis

Trypanosoma cruzi elicits reactive oxygen species (ROS) of inflammatory and mitochondrial origin in infected hosts. In this study, we examined ROS-induced oxidative modifications in the heart and determined whether the resultant oxidized cardiac proteins are targets of immune response and of pathological significance in Chagas disease. Heart biopsies from chagasic mice, rats and human patients exhibited, when compared to those from normal controls, a substantial increase in protein 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), carbonyl, and 3-nitrotyrosine (3-NT) adducts. To evaluate whether oxidized proteins gain antigenic properties, heart homogenates or isolated cardiomyocytes were oxidized in vitro and one- or two-dimensional gel electrophoresis (2D-GE)/Western blotting (WB) was performed to investigate the proteomic oxidative changes and recognition of oxidized proteins by sera antibodies in chagasic rodents (mice, rats) and human patients. Human cardiomyocytes exhibited LD50 sensitivity to 30 µM 4-HNE and 100 µM H2O2 at 6 h and 12 h, respectively. In vitro oxidation with 4-HNE or H2O2 resulted in a substantial increase in 4-HNE- and carbonyl-modified proteins that correlated with increased recognition of cardiac (cardiomyocytes) proteins by sera antibodies of chagasic rodents and human patients. 2D-GE/Western blotting followed by MALDI-TOF-MS/MS analysis to identify cardiac proteins that were oxidized and recognized by human chagasic sera yielded 82 unique proteins. We validated the 2D-GE results by enzyme-linked immunosorbent assay (ELISA) and WB and demonstrated that oxidation of recombinant titin enhanced its immunogenicity and recognition by sera antibodies from chagasic hosts (rats and humans). Treatment of infected rats with phenyl-α-tert-butyl nitrone (PBN, antioxidant) resulted in normalized immune detection of cardiac proteins associated with control of cardiac pathology and preservation of heart contractile function in chagasic rats. We conclude that ROS-induced, cardiac-oxidized antigens are targets of immune recognition by antibodies and molecular determinants for pathogenesis during Chagas disease

Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code – II. The Southern clusters and overview

We investigate the Fe, C, N, O, Mg, Al, Si, K, Ca, Ce, and Nd abundances of 2283 red giant stars in 31 globular clusters from high-resolution spectra observed in both the Northern and Southern hemisphere by the SDSS-IV APOGEE-2 survey. This unprecedented homogeneous data set, largest to date, allows us to discuss the intrinsic Fe spread, the shape, and statistics of Al-Mg and N-C anti-correlations as a function of cluster mass, luminosity, age, and metallicity for all 31 clusters. We find that the Fe spread does not depend on these parameters within our uncertainties including cluster metallicity, contradicting earlier observations. We do not confirm the metallicity variations previously observed in M22 and NGC 1851. Some clusters show a bimodal Al distribution, while others exhibit a continuous distribution as has been previously reported in the literature. We confirm more than two populations in ω Cen and NGC 6752, and find new ones in M79. We discuss the scatter of Al by implementing a correction to the standard chemical evolution of Al in the Milky Way. After correction, its dependence on cluster mass is increased suggesting that the extent of Al enrichment as a function of mass was suppressed before the correction. We observe a turnover in the Mg-Al anticorrelation at very low Mg in ω Cen, similar to the pattern previously reported in M15 and M92. ω Cen may also have a weak K-Mg anticorrelation, and if confirmed, it would be only the third cluster known to show such a pattern