Papers by Iliana Medina-Ramirez
Chemosphere, Oct 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Indoor air pollution has become a threat to human health. People spend much time inside different... more Indoor air pollution has become a threat to human health. People spend much time inside different buildings with heavily polluted indoor air. Human and non-human activities release numerous and diverse pollutants into close environments. Biological pollutants are responsible for numerous respiratory diseases with a broad range of severity (allergies, infectious diseases, cancer). The World Health Organization remarks on the increased number of chronic and acute diseases related to indoor air pollution and urges the development of sustainable technologies for indoor air purification. Although adsorption or UV-assisted techniques exist, there are risks and limitations in their use and practical applications. Lately, some research studies show that photocatalysis is a feasible technique to eliminate indoor air pollutants, increasing indoor air quality and human wellness. Our research group is interested in periodic monitoring of indoor air to offer photocatalytic systems with optimal properties for remediation of the site (indoor air) under study. We aim to have an inventory of air pollutants (qualitative and quantitative analysis) by periodically monitoring its quality. After, we can develop a photocatalytic system for the remediation of the site. We have demonstrated the efficiency of different photocatalytic systems (TiO2-Cu 2+ , Ag@TiO2-Cu 2+ , ZnO-Cu 2+) for hospitals' indoor air disinfection. Our studies show the high disinfection capacity of the materials and their biocompatibility.
Frontiers in Cellular and Infection Microbiology, Jan 28, 2021
Ceramics International, May 1, 2022
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Mathematical Chemistry, Aug 12, 2016
In this work, we propose a discrete mathematical system to model the evolution of the thickness o... more In this work, we propose a discrete mathematical system to model the evolution of the thickness of two-dimensional viscous thin films subject to a dewetting process. The continuous model under consideration is a degenerate partial differential equation that generalizes the classical thin film equation, and considers the inclusion of a singular potential. The analytical model is discretized using an exponential method that is capable of preserving the positive character of the approximations. In addition, the explicit nature of our approach results in an economic computer implementation which produces fast simulations. We provide some illustrative examples on the dynamics of the growth of thin films in the presence/absence of a dewetting process. The qualitative results exhibit the appearance of typical patterns obtained in experimental settings. The technique was validated against Bhattacharya’s method and a standard explicit discretization of the mathematical model.
Applied Surface Science, Aug 1, 2022
Environmental Toxicology and Pharmacology, Aug 1, 2021
The increasing use of metal oxide nanoparticles (MONPs) as TiO2 NPs or ZnO NPs has led to environ... more The increasing use of metal oxide nanoparticles (MONPs) as TiO2 NPs or ZnO NPs has led to environmental release and human exposure. The respiratory system, effects on lamellar bodies and surfactant protein A (SP-A) of pneumocytes, can be importantly affected. Exposure of human alveolar epithelial cells (A549) induced differential responses; a higher persistence of TiO2 in cell surface and uptake (measured by Atomic Force Microscopy) and sustained inflammatory response (by means of TNF-α, IL-10, and IL-6 release) and ROS generation were observed, whereas ZnO showed a modest response and low numbers in cell surface. A reduction in SP-A levels at 24 h of exposure to TiO2 NPs (concentration-dependent) or ZnO NPs (the higher concentration) was also observed, reversed by blocking the inflammatory response (by the inhibition of IL-6). Loss of SP-A represents a relevant target of MONPs-induced inflammatory response that could contribute to cellular damage and loss of lung function.
Nanomaterials, Jun 21, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Computer Methods and Programs in Biomedicine, Jun 1, 2023
Computer Methods and Programs in Biomedicine, Jun 1, 2022
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, May 5, 2017
The objective of this study was to analyze by Raman and UV-Vis-NIR Spectroscopic techniques, Mexi... more The objective of this study was to analyze by Raman and UV-Vis-NIR Spectroscopic techniques, Mexican honey from Apis Mellífera, using representative samples with different botanic origins (unifloral and multifloral) and diverse climates. Using Raman spectroscopy together with principal components analysis, the results obtained represent the possibility to use them for determination of floral origin of honey, independently of the region of sampling. For this, the effect of heat up the honey was analyzed in relation that it was possible to greatly reduce the fluorescence background in Raman spectra, which allowed the visualization of fructose and glucose peaks. Using UV-Vis-NIR, spectroscopy, a characteristic spectrum profile of transmittance was obtained for each honey type. In addition, to have an objective characterization of color, a CIE Yxy and CIE L*a*b* colorimetric register was realized for each honey type. Applying the principal component analysis and their correlation with chromaticity coordinates allowed classifying the honey samples in one plot as: cutoff wavelength, maximum transmittance, tones and lightness. The results show that it is possible to obtain a spectroscopic record of honeys with specific characteristics by reducing the effects of fluorescence.
Food Hydrocolloids
In this work, a deep structural characterization of the chitosan-genipin complex was performed by... more In this work, a deep structural characterization of the chitosan-genipin complex was performed by techniques like small-angle X-ray scattering, dye absorption, atomic force microscopy, compression strength, nitrogen adsorption/desorption, scanning electronic microscopy, and thermogravimetric analysis to understand the changes in the structure through all steps of the process. For this, chitosan beads were modified with Na 2 CO 3 to change porosity and then crosslinked with genipin. The prepared particles were used as support for enzyme immobilization. Our results demonstrated modification in the porosity of the chitosan beads, changing the number of pores and pore volume. After crosslinking process (pH 9), especially the microstructure of chitosangenipin beads was modified, enhancing the fractality and, after enzyme immobilization (pH 4.5) the fractality increased at the higher scale (~100 nm) and reduced at the lower scale (~1-10 nm). β-galactosidase immobilized on the modified particles presented high stability on the continuous production of galactooligosaccharides for 30 days. Our results indicate that the chitosan-genipin complex can be characterized as a plastic and dynamic system due to its structural modifications, particularly in response to changes in the pH environment, even after the crosslinking process.
Adsorption Science & Technology, 2021
In this work, the ability of pectin (Pec) to remove direct red 80 (DR80), Congo red (CR), methyl ... more In this work, the ability of pectin (Pec) to remove direct red 80 (DR80), Congo red (CR), methyl orange (MO), and methyl red (MR) was studied. The removal percentages under adequate pH and ionic strength conditions were as follows: DR80 (99.5%), CR (99.8%), MO (88.6%), and MR (68%), showing that this methodology is efficient to remove azo dyes. The proposed method included the addition of native Pec to the dye aqueous solution and the formation of a gel that occurred when a calcium salt solution was added. This gel retains the molecules adsorbed onto the molecular surface of Pec through hydrogen bonds and electrostatic and hydrophobic interactions. To our knowledge, it is the first time that the Zimm-Bragg model is used to describe the removal of azo dyes with native Pec. This model includes two parameters: K u (nucleation constant), which is related to the tendency exerted by a dye molecule attached to the Pec to bind to other molecules present in the aqueous phase, and U (cooperat...
Journal of Fungi, 2021
Fungal mycoses have become an important health and environmental concern due to the numerous dele... more Fungal mycoses have become an important health and environmental concern due to the numerous deleterious side effects on the well-being of plants and humans. Antifungal therapy is limited, expensive, and unspecific (causes toxic effects), thus, more efficient alternatives need to be developed. In this work, Copper (I) Iodide (CuI) nanomaterials (NMs) were synthesized and fully characterized, aiming to develop efficient antifungal agents. The bioactivity of CuI NMs was evaluated using Sporothrix schenckii and Candida albicans as model organisms. CuI NMs were prepared as powders and as colloidal suspensions by a two-step reaction: first, the CuI2 controlled precipitation, followed by hydrazine reduction. Biopolymers (Arabic gum and chitosan) were used as surfactants to control the size of the CuI materials and to enhance its antifungal activity. The materials (powders and colloids) were characterized by SEM-EDX and AFM. The materials exhibit a hierarchical 3D shell morphology composed...
Revista de la Sociedad Química de Mexico, 2017
The interaction of Alginic acid with three direct dyes (Direct blue 1, Direct red 81, and Direct ... more The interaction of Alginic acid with three direct dyes (Direct blue 1, Direct red 81, and Direct black 22) was studied. It was found that as a result of this interaction formation of adducts after addition of calcium ion, facilitates their removal from aqueous solution. Our re- sults suggest a relationship among physico-chemical properties of each dye and its removal efficiency. The main mechanisms involved in dye removal are electrostatic interactions, hydrogen bonding and hy- drophobic interactions.
Revista Internacional de Contaminación Ambiental, 2019
Palabras clave: agregación, grupos funcionales, gelificación RESUMEN Los colorantes azo represent... more Palabras clave: agregación, grupos funcionales, gelificación RESUMEN Los colorantes azo representan entre 60 y 75 % de los colorantes producidos actualmente. Se utilizan ampliamente en la industria cosmética, del papel, optoelectrónica, textil, etc. Desafortunadamente una vez utilizados, debido a su alta resistencia a tratamientos convencionales de aguas residuales, contaminan los cuerpos de agua donde son descargados. En este reporte se utiliza alginato de sodio (ALG) para remover los colorantes azo rojo directo 80 (RD80), rojo congo (Rcongo) y rojo de metilo (Rmetilo). Estudios de espectroscopía UV-visible, FTIR y Raman ayudaron a elucidar los tautómeros involucrados en su remoción. Los porcentajes de remoción fueron: RD80 (99.9 % a pH = 12 y fuerza iónica= 0.1 M), Rcongo (99.7 % a pH = 12 y fuerza iónica = 0.1 M) y Rmetilo (14.9 % a pH = 7 y fuerza iónica = 0.1 M). El modelo de Zimm-Bragg describe adecuadamente las isotermas experimentales, sugiriendo la importancia de la agregación de los colorantes en su eficiencia de remoción. Adicionalmente, se comparó la eficiencia de remoción de siete colorantes azo y se encontró que moléculas con peso molecular elevado, con alta planaridad y carga positiva mostraron las mayores eficiencias de remoción. Lo anterior permite predecir cualitativamente a partir de las estructuras de colorantes azo, cuál de ellos será removido más eficientemente con el ALG.
Ceramics International, 2020
Magnetic nanostructured materials have found numerous biomedical applications. However, the influ... more Magnetic nanostructured materials have found numerous biomedical applications. However, the influence of a magnetic field on the inhibition of pathogenic microorganisms has been poorly explored. Zinc and Iron nano-structured oxides have been widely used due to their biocompatibility and their excellent optoelectronic and magnetic properties. Nevertheless, little effort has been devoted to demonstrate their antibacterial activity at doses that are not harmful to mammalians. In this work, ZnO, Fe 3 O 4 (MNPs) and ZnO@Fe 3 O 4 (NCs) were synthesized and fully characterized. The materials exhibit good antibacterial activity to inhibit the growth of Staphylococcus aureus (S. aureus) and Helicobacter pylori (H. pylori) both, as planktonic cells and as biofilms structures at low doses. The photocatalytic activity of the materials (NCs) was demonstrated when radiated suspensions of NCs and microorganisms (MOs) exhibited higher inhibition growth of MOs in comparison to non-radiated assays. The materials show better antibacterial activity for biofilm growth inhibition in comparison to commercially available antibiotics. Magnetic antimicrobial films were fabricated by in situ deposition of MNPs in Arabic gum (AG) solution. The films exert enhanced antibacterial activity against S. aureus growth due to Fe 3+ lixiviation and magnetic disruption. Regarding the biocompatibility of the materials, ZnO modifies significantly biochemical parameters in Wistar rats after acute administration. Our results show that the composite ZnO@Fe 3 O 4 at low doses: (a) exerts an optimum inhibition on the biofilm formation of microorganisms due to its synergetic activity of lixiviation of ions and oxidative activity; (b) good biocompatibility of the composite with living cells. These properties suit ZnO@Fe 3 O 4 as potential candidates for the development of new anti-biofilm formulation.
Journal of the Mexican Chemical Society, 2019
The interaction among Xanthan (XANT) and three azo dyes: Direct blue 1 (DB1), Direct red 81 (DR81... more The interaction among Xanthan (XANT) and three azo dyes: Direct blue 1 (DB1), Direct red 81 (DR81), and Direct black 22 (DB22) was studied. The Xanthan-dye-Al product was formed after the addition of AlCl3 to a Xanthan-Dye adduct containing solution. It was proposed that polyhydroxyoxoaluminum clusters named CAL-13 and CAL-30 react with this adduct producing a Xanthanate aluminum network, XANT-Al, and as a consequence a decrease in dye concentration in an aqueous medium was observed. The removal efficiencies obtained were the following: DB1 (99 %), DB22 (99 %) and DR81 (94 %), demonstrating that this dye removal method is very efficient. The Zimm-Bragg model adequately described the experimental data and the order observed in the Ku (nucleation) and U (aggregation) parameters from this model was the following: DB1>DB22> DR81. Evidence suggests that physicochemical properties of dyes such as charge, molecular weight, aggregation ability and the capacity of XANT-Al to trap dye m...
Cancer Investigation, 2019
Cancer treatment by magnetic hyperthermia offers numerous advantages, but for practical applicati... more Cancer treatment by magnetic hyperthermia offers numerous advantages, but for practical applications many variables still need to be adjusted before developing a controlled and reproducible cancer treatment that is bio-compatible (nondamaging) to healthy cells. In this work, Fe 3 O 4 and CoFe 2 O 4 were synthesized and systematically studied for the development of efficient therapeutic agents for applications in hyperthermia. The biocompatibility of the materials was further evaluated using HepG2 cells as biological model. Colorimetric and microscopic techniques were used to evaluate the interaction of Magnetic Nano-Materials (MNMs) and HepG2 cells. Finally, the behavior of MNMs was evaluated under the influence of an Alternating Magnetic Field (AMF), observing a more efficient temperature increment for CoFe 2 O 4 , a desirable behavior for biomedical applications since lower doses and shorter expositions to alternating magnetic field might be required.
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Papers by Iliana Medina-Ramirez