A Three-Way Catalyst (TWC) contains a cordierite ceramic monolith coated with a layer of Al₂O₃, Ce_xZr_1−xO₂ and platinoids mixture. Under standard operation, the platinoid concentration decreases, exposing the remaining washcoat structure. After that particle release stage, the sintering process follows where the crystalline Ce_xZr_1−xO₂ solution is broken and begins to separate into ZrO₂ and CeO₂ phases. ZrO₂ is released to the environment as micro and nanoparticles, while a small amount of CeO₂ generates a new Al_xCe_1−xO₂ composite. The main effect of Ce capture is the growth in the size of the polycrystal structure from 86.13 ± 16.58 nm to 225.35 ± 69.51 nm. Moreover, a transformation of cordierite to mullite was identified by XRD analysis. Raman spectra showed that the oxygen vacancies (Vö) concentration decreased as Ce_xZr_1−xO₂ phases separation occurred_. The SEM-EDS revealed the incorporation of new spurious elements and microfractures favouring the detachment of the TWC support structure. The release of ultrafine particles is a consequence of catalytic devices overusing. The emission of refractory micro to nanocrystals to the atmosphere may represent an emerging public health issue underlining the importance of implementing strict worldwide regulations on regular TWCs replacement.

Nanodiamonds have been studied for several biomedical applications due to their inherent biocompatibility and low cytotoxicity. Recent investigations have shown perspectives in using fluorescent nanodiamonds as nanothermometers because of their optical properties’ dependence on temperature. Easy and accurate localized temperature sensing is essential in a wide variety of scientific fields. Our work demonstrated how the fluorescence spectrum of high-pressure high-temperature fluorescent nanodiamonds of three different sizes: 35 nm, 70 nm and 100 nm, changes with temperature within an important biological temperature range (25 °C to 60 °C). Taking advantage of this phenomenon, we obtained nanothermic scales (NS) from the zero phonon lines (ZPL) of the NV⁰ and NV⁻ colour centres. In particular, the 100 nm-sized features the more intense fluorescence spectra whose linear dependence with temperature achieved 0.98 R² data representation values for both NV⁰ and NV⁻. This model predicts temperature for all used nanodiamonds with sensitivities ranging from 5.73% °C⁻¹ to 6.994% °C⁻¹ (NV⁰) and from 4.14% °C⁻¹ to 6.475% °C⁻¹ (NV⁻). Furthermore, the non-cytotoxic interaction with HeLa cells tested in our study enables the potential use of fluorescence nanodiamonds to measure temperatures in similar nano and microcellular aqueous environments with a simple spectroscopic setup.

Antecedentes y Objetivos: “Bacanora” es una bebida espirituosa que emplea como materia prima principalmente las poblaciones silvestres de Agave angustifolia, las cuales requieren estrategias de conservación debido a su sobre aprovechamiento. El objetivo de este trabajo fue evaluar la variación morfológica y el contenido de azúcares reductores totales y fructanos del tallo de A. angustifolia proveniente de poblaciones silvestres conservadas en Sonora, México. Métodos: Se estudiaron tres poblaciones silvestres conservadas de A. angustifolia, en Sonora, México, en 29 variables relacionadas con las características morfológicas, indicadores de madurez fenológica y el contenido de azúcares reductores y fructanos. Resultados clave: El contenido de fructanos y azúcares reductores totales del tallo presentaron un promedio de 22.6 y 32.7 g/100 g (base seca) respectivamente; con una variación significativa entre las poblaciones silvestres (p<0.05). De las de 29 variables evaluadas, el estudio de componentes principales indicó que con cuatro componentes se explica 51.9% de la varianza de los datos. El análisis canónico discriminante de las 16 variables que mostraron mayor relación con los cuatro componentes principales definió el agrupamiento de las poblaciones. Dos funciones canónicas separaron significativamente (p<0.001) a las tres poblaciones silvestres de agave y representaron 100% de la varianza total. Conclusiones: Las variables con mayor contribución e importancia relativa asociadas a cada población fueron el desarrollo de la inflorescencia, el contenido de azúcares reductores totales del tallo, así como el tono y la saturación de color de las hojas. Background and Aims: “Bacanora” is a spirit drink that uses mainly wild populations of Agave angustifolia as raw material, which require conservation strategies due to their overuse. The aim of this work was to evaluate the morphological variation and the content of total reducing sugars and fructans in the stem of A. angustifolia in conserved wild populations from Sonora, Mexico.Methods: Three conserved wild populations of A. angustifolia were studied by 29 variables related to morphological characters, phenological maturity indicators, and the content of reducing sugars and fructans.Key results: The content of fructans and total reducing sugars in the stem presented an average of 22.6 and 32.7 g/100 g (dry basis) respectively, with a significant variation among wild populations (p<0.05). Of the 29 variables evaluated, a principal component analysis indicated that 51.9% of the data variance is explained with four components. A discriminant canonical analysis with the 16 variables that showed the greatest relationship with the four main components defined the grouping of the populations. Two canonical functions significantly separated (p<0.001) the three wild agave populations and represented 100% of the total variance.Conclusions: The variables with the greatest contribution and relative importance associated with each population were the development of the inflorescence, the content of total reducing sugars in the stem, as well as the tone and color saturation of leaves.

This work provides the first description of the synthesis and characterization of polymeric nanoparticles (NPs) obtained by polyelectrolyte complexes (PECs) of three polysaccharides: chitosan (Cs) or its catecholic derivative, ulvan, and hyaluronic acid (HA). The carbodiimide method used catechol group conjugation onto the Cs backbone using the catechol-containing compound hydrocaffeic acid. A degree of substitution of 2.98% was determined by spectroscopy in the chitosan-catechol (CsC) conjugate. DLS studies showed hydrodynamic diameter (D _h) close to 300 nm for PECs of Cs and CsC with ulvan, with positive zeta potential for both complexes. HA coating was confirmed by obtaining negative zeta potential. The HA coating reduced the D _h values of the materials by approximately 100 nm. This resulted in maintaining stability in water suspension for up to 8 weeks, yielding unimodal size distribution. ATR-FTIR spectra confirmed the presence of the polyelectrolytes in the PECs. FE-SEM studies demonstrated that HA-coated NPs exhibited smaller sizes than their uncoated counterparts. PECs with CsC maintained higher free radical scavenging activity than those with unmodified Cs, with the HA coating only reducing antioxidant activity by 16%. All tested NPs demonstrated biocompatibility at concentrations up to 200 μg/mL in ARPE-19 cell cultures derived from human retinal pigment epithelial cells.

Background: Reports in a northwestern Mexico state linked arsenic (As) in drinking water to DNA damage in people from indigenous communities. However, this correlation remains under discussion due to unknown variables related to nutrition, customs, and the potential presence of other metal(oid)s. Methods: To determine this association, we sampled water from three Yaqui towns (Cócorit, Vícam, and Pótam), and analyzed the metals by ICP-OES. We exposed four separate groups, with five male CD-1 mice each, to provide further insight into the potential effects of untreated drinking water. Results: The maximum concentrations of each metal(oid) in µg·L⁻¹ were Sr(819) > Zn(135) > As(75) > Ba(57) > Mo(56) > Cu(17) > Al(14) > Mn(12) > Se(19). Histological studies revealed brain cells with angulation, satellitosis, and reactive gliosis with significant statistical correlation with Mn and As. Furthermore, the liver cells presented hepatocellular degeneration. Despite the early response, there is no occurrence of both statistical and significative changes in hematological parameters. Conclusions: The obtained results provide experimental insights to understand the potential effects of untreated water with low As and Mn contents in murine models. This fact is noteworthy because of the development of histological changes on both the brain and liver at subchronic exposure.