Hydroxyapatite (HAp) nanoparticles with a homogeneous rod morphology were successfully synthesized using the hydrothermal method. The powders were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The antibacterial and dermal irritation analyses of the samples were performed and discussed. The use of cationic and anionic surfactants, namely, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), respectively, at a low concentration (2.5 mol%) modified the length/diameter (L/D) ratio of the HAp rods. Structural characterizations of hydroxyapatite synthesized without surfactant (HA), with 2.5 and 5 mol% of SDS (SDS− and SDS+, respectively), and with 2.5 and 5 mol% of CTAB (CTAB− and CTAB+, respectively) revealed well-crystallized samples in the hexagonal phase. The CTAB− sample presented antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Streptococcus anginosus, Staphylococcus aureus, Micrococcus luteus, and Klebsiella pneumoniae, suggesting that antimicrobial susceptibility was promoted by the bacterial nature and the use of the surfactant. Dermal irritation showed no clinical signs of disease in rabbits during the study, where there was neither erythema nor necrosis at the inoculation sites.

Se caracterizaron química, física y mineralógicamente agregados minerales finos mexicanos, tales como: ceniza volante, microsílice, humo de sílice, escoria granulada de alto horno (EGAH) gruesa, fina y refinada para su dosificación con cemento Portland compuesto (CPC) en su estado normal y refinado por molienda de alta energía (HEM), con el objetivo de fabricar un concreto de alto desempeño (CAD), partiendo de subproductos industriales. Los materiales fueron acondicionados con tamaños menores a #200 mallas (75μm) y algunos con partículas del orden submicrométrico para analizar el aporte en la resistencia a la compresión dentro de las mezclas. Una vez caracterizada la materia prima se determinaron los parámetros experimentales para reducir los tamaños de partícula mediante HEM del cemento Portland compuesto y la escoria granulada de alto horno. Los productos de molienda, así como los demás materiales cementantes fueron caracterizados por: difracción de rayos X (DRX), microscopía electrónica de barrido (MEB) y absorción atómica. Se identificaron las fases presentes en dichos materiales, detectando una modificación en el porcentaje de las fases Alita C3S y Belita C2S favoreciendo la resistencia a la compresión, especialmente al moler el CPC durante 30 min por HEM. Los ensayos de resistencia a la compresión de las probetas del CAD obtenidas comprueban que la mayor resistencia a la compresión se alcanza usando humo de silice HS.

This study focused on synthesizing AlNiCo and CoNi materials using a low-energy milling process. The aim was to explore the formation of low-energy phases in both systems, contrasting with the typical research on phases formed under high-energy conditions. In the Co-20 wt% Ni system, the phases ${\mathrm{Co}}_{0.75}{\mathrm{Ni}}_{0.25}$ and Ni were identified, as well as the FCC cubic phase of CoNi, using X-ray diffraction (XRD) with a molybdenum radiation source. The observed behavior aligned closely with the miscibility curve in the equilibrium phase diagram, which included a region of alloys with varying structures and similar compositions. A notable feature was the presence of a predominantly dispersed hexagonal Ni zone, consisting of nanoparticles. Transmission electron microscopy (TEM) was employed to observe the FCC CoNi phase, which displayed a specific arrangement. AlNiCo and CoNi alloys were successfully synthesized through mechanical alloying, incorporating equilibrium and non-equilibrium phases.