Publications by authors named "I Santacruz"
Portland cements (PCs) and cement blends are multiphase materials of different fineness, and quantitatively analysing their hydration pathways is very challenging. The dissolution (hydration) of the initial crystalline and amorphous phases must be determined, as well as the formation of labile (such as ettringite), reactive (such as portlandite) and amorphous (such as calcium silicate hydrate gel) components. The microstructural changes with hydration time must also be mapped out.
View Article and Find Full Text PDFPRECORSE study: Seroprevalence of severe acute respiratory syndrome coronavirus 2 in the first trimester of pregnancy during the first wave of the COVID-19 pandemic and subsequent pregnancy complications-A cohort study.
Int J Gynaecol Obstet
October 2023
Article Synopsis
- Researchers have struggled to fully understand cement dissolution and precipitation processes for the past century due to limitations in imaging techniques.
- The study utilizes near-field ptychographic nanotomography to visualize the hydration of Portland cement, revealing a porous C-S-H gel shell forming around alite grains within 19 hours.
- It was found that small alite grains dissolve approximately four times faster than larger ones, and the work aims to further explore these processes with advanced imaging techniques, including the effects of additives like accelerators and superplasticizers.
Purpose: To analyze antibiotic resistance and genetic profile of conjunctival bacteria flora before and after cataract surgery with the focus on coagulase-negative staphylococci (CNS) during cataract surgery and discuss the implications of this colonization as a potential risk of acquiring endophthalmitis.
Methods: After approval of the institutional review board and informed consent from patients had been obtained, conjunctival swabs for culture from 59 patients undergoing cataract surgery were taken of the fellow eye at baseline (C0) and from the eye to be operated before (T0) and after (T1) irrigation with povine-iodine 5%, and at the end of surgery (T2). Genes responsible for virulence (mecA, ica and atlE) and antibiotic profile were determined; strain clonality of persistent colonizing Staphylococcus epidermidis strains was established by the Multi-locus sequence typing (MLST).
The effect of superplasticiser, borax and the water-to-cement ratio on BYF hydration and mechanical strengths has been studied. Two laboratory-scale BYF cements-st-BYF (with β-CS and orthorhombic CAS¯) and borax-activated B-BYF (with α'-CS and pseudo-cubic CAS¯)-have been used, and both show similar particle size distribution. The addition of superplasticiser and externally added borax to BYF pastes has been optimised through rheological measurements.
View Article and Find Full Text PDF