Effects of chemical aging on carbonaceous materials: Stability of water-dispersible colloids and their influence on the aggregation of natural-soil colloid.

Although hydrochar and biochar have been used as soil conditioners, there is not a clear understanding of how their properties changes due to aging impacts their colloidal particles behavior on the soil system. From this premise, we produced hydrochar and biochar from the same feedstock (cashew bagasse) and aged with different chemical methods: (i) using hydrogen peroxide, (ii) a mixture of nitric and sulfuric acids, and (iii) hot water. It was analyzed the effects of aging on the stability of the carbonaceous materials (CMs) colloids in aqueous medium with different ionic strength (single systems), as well as the stability of the natural-soil colloid when interacting with biochar and hydrochar colloids (binary systems). A chemical composition (C, H, N, and O content) change in CMs due to the chemically induced aging was observed along with minor structural modifications. Chemical aging could increase the amount of oxygen functional groups for both biochar and hydrochar, though in a different level depending on the methodology applied. In this sense, hydrochar was more susceptive to chemical oxidation than biochar. The effectiveness of chemical aging treatments for biochar increased in the order of water < acid < hydrogen peroxide, whereas for hydrochar the order was water < hydrogen peroxide < acid. While the increase in surface oxidation improved the biochar colloidal stability in water medium at different ionic strengths (single systems), the stability and critical coagulation concentration (CCC) slightly changed for hydrochar. Natural-soil clay (NSC) interactions with oxidized carbonaceous material colloids (binary systems) enhanced NSC stability, which is less likely to aggregate. Therefore, the aging of carbonaceous materials modifies the interaction and dynamics of soil small particles, requiring far more attention to the environmental risks due to their application over time.

Compositional and microhardness findings in tooth affected by X-linked hypophosphatemic rickets.

BACKGROUND: This study aimed to evaluate the X-linked hypophosphatemic rickets (XLHR)-related compositional and microhardness tooth aspects. MATERIAL AND METHODS: One affected and one non-affected teeth by XLHR were sectioned transversely, and each section was separated for Micro-Raman spectroscopy, Knoop microhardness and scanning electron microscopy with energy dispersive x-ray microanalysis (SEM-EDS). The outcomes of these analyses were assessed. RESULTS: Outcomes of Raman analysis of inorganic/organic components (~958/~1250+~1450 cm-1) and carbonate/phosphate (~1070/~958 cm-1) ratios showed areas of altered enamel and dentin (interglobular dentin, calcospherites, and mantle dentin) with an increase of inorganic content in the rickets tooth. Microhardness reduction was observed in the affected tooth, with a more evident drop in regions of mantle dentin, interglobular dentin, and calcospherites. SEM-EDS analysis showed demonstrated the absence of calcium and phosphorus in interglobular spaces. CONCLUSIONS: In conclusion, compositional and structural deficiencies were observed in deciduous tooth affected by XLHR. Also, it was observed the absence of hydroxyapatite in the interglobular dentin by using Raman spectroscopy analysis. Key words:Dentin, dentin permeability, X-linked hypophosphatemic rickets, tooth, tooth calcification, Raman spectroscopy.

Improving Properties of Albendazole Desmotropes by Supramolecular Systems with Maltodextrin and Glutamic Acid.

Albendazole, an effective broad-spectrum anthelmintic agent, showed unpredictable therapeutic response caused by poor water solubility and slow dissolution rate. Then, novel binary and multicomponent supramolecular systems of two different solid forms of albendazole (I and II) with maltodextrin alone or with glutamic acid were studied as an alternative to improve the oral bioavailability of albendazole. The interactions and effects on the properties of albendazole were studied in solution and solid state. The solid systems were characterized using Raman and Fourier transform-infrared spectroscopy, thermal analysis, powder X-ray diffraction, and scanning electron microscopy. The solubility measurements, performed in aqueous and simulated gastric fluid, showed that albendazole (form II) was the most soluble form, while its supramolecular systems showed the highest solubility in simulated gastric fluid. On the other hand, the dissolution profiles of binary and multicomponent systems in simulated gastric fluid displayed pronounced increments of the dissolved drug and a faster dissolution rate compared to those of free albendazole forms. Thus, these supramolecular structures constitute an interesting alternative to improve the physicochemical properties of albendazole, with potential application for the preparation of pharmaceutical oral formulations.