ABSTRACT Introduction: Changes in ventricular geometry in hypertensive patients are influenced by 24-hour control of blood pressure, as well as its adequate decrease during nighttime. Objective: To describe the left ventricle geometric patterns in patients with or without nocturnal hypertension. Method: An ambulatory blood pressure monitoring (ABPM) and an echocardiogram were performed on 54 patients with high blood pressure, from 2016 to 2017. The following ABPM variables were calculated: average and pressure loads of daytime, nighttime, and 24-hour, as well as circadian pattern. In the echocardiogram, the diameters, the interventricular septum and the left ventricular posterior wall were measured; its mass and mass index were calculated, as well as determined its geometric and diastolic function patterns. Results: The average age was 57.4%±14.1 years old. Females (57.4%) and white skin color (59.3%) predominated. Waking and nocturnal hypertension were found in 38.9% and 51.9% respectively, and the altered dipper phenomenon was found in 68.5% of the patients, significantly associated with increased nocturnal blood pressure (p=0.001). The interventricular septum was considerably higher in patients with nocturnal hypertension when compared to the group without it (11.1±2.2 vs. 9.6±1.4 mm; p=0.006). Altered geometry predominated (53.7%) at the expense of higher concentric remodeling (40.7%), without any association with nocturnal hypertension. Conclusions: Left ventricle geometric patterns behaved similarly in patients with and without nocturnal hypertension.

RESUMEN Introducción: En los cambios de la geometría ventricular en hipertensos influyen el control de la presión arterial durante las 24 horas del día, así como su descenso adecuado en el período nocturno. Objetivo: Describir los patrones geométricos del ventrículo izquierdo en pacientes con y sin hipertensión arterial nocturna. Método: Se realizó monitoreo ambulatorio de la presión arterial (MAPA) y ecocardiograma a 54 pacientes con hipertensión arterial del 2016 al 2017. Se calcularon las variables de MAPA: promedio y cargas de presión diurno, nocturno y 24 horas, y el patrón circadiano. En el ecocardiograma se midieron los diámetros, el tabique interventricular y la pared posterior del ventrículo izquierdo, se calculó su masa e índice de masa, y se determinó su patrón geométrico y de función diastólica. Resultados: La edad promedio fue 55,4±14,1 años y predominaron el sexo femenino (57,4%) y el color de la piel blanco (59,3%). La hipertensión arterial al despertar y nocturna se halló en el 38,9% y 51,9%, respectivamente, y el fenómeno dipper alterado en 68,5% de los pacientes, asociado significativamente al incremento de la presión arterial nocturna (p=0,001). El tabique interventricular fue significativamente mayor en pacientes con hipertensión arterial nocturna en comparación con el grupo que no la presentaba (11,1±2,2 vs. 9,6±1,4 mm; p=0,006). Predominó la geometría alterada (53,7%) a expensas de mayor remodelado concéntrico (40,7%), sin asociación con la hipertensión arterial nocturna. Conclusiones: Los patrones geométricos del ventrículo izquierdo se comportaron de forma similar en pacientes con y sin hipertensión arterial nocturna.

O processo de climatizacao de um concreto de alta resistencia mecanica (VHSC) foi estudado e comparado com o de um concreto comum. O concreto VHSC apresenta resistencia a compressao muito maior que 100 MPa apos sete dias de cura. A resistencia a compressao aumenta com a diminuicao do valor da relacao agua/cimento e melhorando a distribuicao de tamanho de particula dos inumeros graos anidros residuais de clinquer e dos agregados de quartzo. Uma proporcao de 15% do cimento e substituida por residuo de silica nao condensada, que consiste de particulas esfericas de silica amorfa de 0,1 µm de diametro, com a vantagem de preencher o espaco entre as particulas de clinquer. Outra vantagem e densificar a zona interfacial entre a pasta de cimento e os agregados. Apos 28 dias de cura, as amostras de concreto VHSC consistem de agregados de quartzo e residuos de particulas anidras de clinquer ligadas umas as outras com uma pasta composta principalmente de hidrato silicato de calcio (C-S-H). Amostras de concreto VHSC foram imersas em agua destilada continuamente renovada sob atmosfera inerte. Apos dois meses de exposicao, ocorreram mudancas quimicas, mineralogicas e texturais em uma zona na superficie. A profundidade da zona degradada foi 300 µm. Este valor e muito menor que a profundidade da zona degradada formada em uma argamassa comum (800 µm) ou em uma pasta comum (1500 µm) submetida a mesma condicao. Na superficie das amostras climatizadas de concreto VHSC, as particulas anidras de clinquer dissolveram e o vazio resultante de 10 µm de diametro permaneceu vazio. Na fronteira entre o interior isolado e a zona climatizada da superficie os vazios resultantes da dissolucao das particulas de clinquer foram preenchidos com C-S-H secundario. Como conclusao, a baixa porosidade do concreto VHSC foi benefica para a resistencia a compressao e tambem para a durabilidade. A presenca de inumeras particulas anidras de clinquer nao resultou em problema.

We studied the weathering process of a very high strength concrete (VHSC) and compared it with that of a usual concrete. VHSC has compressive strengths much above 100 MPa after seven days of curing. The compressive strength is increased by lowering the value of the water/cement ratio and by improving the particle size distribution of the numerous residual anhydrous grains of clinker and of the quartz aggregates. A proportion of 15% of the cement is replaced by non-condensed silica fume, which consists of spherical particles of amorphous silica, 0.1 µm in diameter. This has the advantage to fill the space between clinker particles. Another advantage is to densify the interfacial zone between cement paste and aggregates. Afters 28 days of curing, the VHSC samples consist of quartz aggregates and residual anhydrous clinker particles linked to each other with a paste mainly composed of calcium silicate hydrate (C-S-H). Samples of VHSC were immersed in continuously renewed distilled water under inert atmosphere. After two months of exposure, chemical, mineralogical and textural changes have occurred in a superficial zone. The depth of the degraded zone is 300 µm. This value is much lower than the depth of the degraded zone formed in an usual mortar (800 µm) or in a common paste (1500 µm) leached in the same condition. At the surface of the weathered samples of VHSC, the anhydrous clinker particles have dissolved and the resulting holes of 10 µm diameter remained empty. At the frontier between the safe core and the weathered superficial zone, the holes resulting from the dissolution of clinker particles were filled with secondary C-S-H. As a conclusion, the low porosity of VHSC is a benefit for the compressive strength but also for the durability. The presence of numerous anhydrous clinker particles is not a problem.

Cimento é um material de ampla utilização que pode ser sujeito a modificação pelo tempo. A modificação química do cimento em meio natural é principalmente caracterizada por lixiviação de CaO e adição de CO2. As diferentes zonas de resistência que se desenvolvem às custas do cimento podem ser previstas com os diagramas de fase do potencial químico; estes diagramas simulam o comportamento de sistemas abertos a alguns elementos químicos. Alguns componentes têm o chamado status inerte, significando que o sistema é fechado para estes componentes, seu teor no sistema permanece constante; alguns outros componentes tem um status móvel, significando que estes componentes podem ser trocados com o meio exterior, seu teor podendo variar de uma região da amostra para outra. Os componentes móveis são representados no modelo pelos potenciais químicos (ligados às suas concentrações) que variam no meio exterior. Os principais aspectos da resistência ao tempo de um sistema cementício aberto a CaO e CO2 são previstos em um diagrama de fases com µCaO e µCO2 como eixos do diagrama. Do centro para a extremidade observa-se o desaparecimento de portlandita, ettringita e monosulfoaluminato de cálcio, a precipitação de calcita e sílica amorfa, a modificação da composição de minerais CSH (silicatos de cálcio hidratados) que tem o decréscimo da razão c/s (CaO/SiO2) do centro para a extremidade da amostra. Para os minerais CSH, forma separadas as soluções sólidas contínuas em três composições definidas por diferentes razões CaO/SiO2, denominadas fases 1, 2 e 3: CaO = 0,8, 1,1, 1,8, respectivamente para 1 mol SiO2 sabendo que H2O varia nas três composições.

Cement is a ubiquitous material that may suffer hazardous weathering. The chemical weathering of cement in natural environment is mostly characterized by the leaching of CaO and the addition of CO2. The different weathering zones that develop at the expense of the cement may be predicted by the help of chemical potential phase diagrams; these diagrams simulate the behaviour of systems open to some chemical elements. Some components have a so-called inert status, that is to say the system is closed for these components, their amount in the system remains constant; some other components have a mobile status, that is to say these components can be exchanged with the outside of the system, their amount can vary from one sample zone to another. The mobile components are represented in the model by their chemical potentials (linked to their concentrations) that are variable in the external environment. The main features of the weathering of a cement system open to CaO and CO2 are predicted in a phase diagram with µCaO et µCO2 as diagram axes. From core to rim, one observes the disappearance of portlandite, ettringite and calcium monosulfoaluminate, the precipitation of calcite and amorphous silica, the modification of the composition of the CSH minerals (hydrated calcium silicates) that see a decrease of their c/s ratio (CaO/SiO2) from the core to the rim of the sample. For the CSH minerals, we have separated their continuous solid solution into three compositions defined by different CaO/SiO2 ratios and called phases 1, 2 and 3: CaO = 0.8, 1.1, 1.8 respectively for one mole of SiO2 knowing that H2O varies in the three compositions.