Iliana Medina Ramirez

Autonomous University of Aguascalientes | UAA · Departamento de Química

Modern imaging strategies are paramount to studying living systems such as cells, bacteria, and fungi and their response to pathogens, toxicants, and nanomaterials (NMs) as modulated by exposure and environmental factors. The need to understand the processes and mechanisms of damage, healing, and cell survivability of living systems continues to mo...

Background and objective: In this manuscript, we consider a compartmental model to describe the dynamics of propagation of an infectious disease in a human population. The population considers the presence of susceptible, exposed, asymptomatic and symptomatic infected, quarantined, recovered and vaccinated individuals. In turn, the mathematical mo...

BACKGROUND. We provide a compartmental model for the transmission of some contagious illnesses in a population. The model is based on partial differential equations, and takes into account seven sub-populations which are, concretely, susceptible, exposed, infected (asymptomatic or symptomatic), quarantined, recovered and vaccinated individuals alon...

Nanomaterials such as titanium dioxide and magnetite are increasingly used in several fields, such as water remediation and agriculture. However, this has raised environmental concerns due to potential exposure to organisms like humans. Nanomaterials can cause adverse interactions depending on physicochemical characteristics, like size, morphology,...

Fungal infections have become a significant public health concern due to their increasing recurrence and harmful effects on plants, animals, and humans. Opportunistic pathogens (among others from the genera Candida and Aspergillus) can be present in indoor air, becoming a risk for people with suppressed immune systems. Engineered nanomaterials are...

Nanomaterials (NMs) can solve some of the current challenges for the treatment of infectious, chronic, or degenerative diseases. The advances in nanoscience and nanotechnology allow scientists the development of NMs with optimal properties for specific applications. Although numerous NMs are nowadays commercially available, few of them end up in bi...

The SiO2-TiO2 composite has been studied through several techniques obtaining different morphologies and specific properties of SiO2 and TiO2. Nevertheless, the modification of the synthesis pH and the addition of different hydrophobic agents, such as hexamethyldisilazane (HDMS) and polydimethylsiloxane (PDMS), have not been thoroughly studied and...

Diseases induced by phytopathogenic fungi generate considerable economic losses and severe damage to agricultural crops. The objective of this research was to evaluate the inhibitory effect in vitro of carbon nanotubes with extracts of Bacillus amyloliquefaciens on the mycelial development of Rhizoctonia solani (Rs), Fusarium solani (Fs), Colletotr...

Zinc oxide is one of the most versatile nanostructured materials with a broad range of applications. Besides, its physicochemical properties can be tuned easily by synthesis conditions to be optimal for a specific application. In our group, we aim for the production of visible light-active materials with enhanced antimicrobial activity. Thus, we sy...

Fungal mycoses have become an important health and environmental concern due to the numerous side deleterious 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, CuI nanomaterials (NMs) were synthesized...

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...

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 highe...

Among the different properties of the hydrophobic semiconductor surfaces, self-cleaning promoted by solar illumination is probably one of the most attractive from the technological point of view. The use of sonochemistry for nanomaterials' synthesis has been recently employed for the associated shorter reaction times and efficient route for control...

Entamoeba histolytica is an invasive enteric protozoan, whose infections are associated to high morbidity and mortality rates. However, only less than 10% of infected patients develop invasive amebiasis. The ability of E. histolytica to adapt to the intestinal microenvironment could be determinant in triggering pathogenic behavior. Indeed, during c...

Safety on the use of magnetic nanomaterials (MNMs) has become an active topic of research given all the recent applications of these materials in various fields. It is known that the toxicity of MNMs depends on size, shape, and surface functionalization. In this study, we evaluate the biocompatibility with different aquatic organisms of engineered...

Nowadays, air pollution has become a global menace being responsible of a significant increase on the morbidity and mortality of human beings. In view of this, sustainable and efficient technologies for air purification are being sought. Air purification by photocatalytic treatment has received a lot of attention due to the unspecific and high oxid...

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. Nevert...

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...

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 (non-damaging) to healthy cells. In this work, Fe3O4 and CoFe2O4 were synthesized and systematically studied for the dev...

[email protected] is an important class of material with applications as catalysts, photocatalysts, optoelectronic devices and antimicrobial agents. Because of its potential for large-scale applications and its high redox activity, detailed examination of the properties and risk assessment of this class of materials should be performed. In this wor...

The azo dyes represent between 60-75 % of the total of dyes produced nowadays. They are widely used in cosmetic industry, paper, optoelectronic, textile, etc. Unfortunately, due to their high resistance to the conventional treatments applied to wastewaters, they pollute the water bodies where are discharged. In this report, the sodium alginate (ALG...

In this article, visible light active, copper doped TiO2 nanoparticles are discussed as potential candidates for the tertiary treatment of industrial effluents. Our aim was to develop sustainable photocatalytic materials that exhibit excellent activity and biocompatibility. The photocatalysts were prepared using a two-step procedure: sol-gel synthe...

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 possibi...

In this work, we report the synthesis, characterization and photocatalytic evaluation of visible light active iron-nitrogen co-doped titanium dioxide (Fe³⁺-TiO2-xNx) nanostructured catalyst. Fe³⁺-TiO2-xNx was synthesized using two different chemical approaches: sol-gel (SG) and microwave (MW) methods. The materials were fully characterized using se...

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 pote...

Nanostructured materials (NSMs) of silver (Ag@TiO 2 ) and copper (TiO 2 -Cu 2+ ) doped titanium dioxide were synthesized, fully characterized, and evaluated for their antimicrobial efficiency and effects on Arabidopsis thaliana . The NSMs were prepared using an environmentally benign route. The physicochemical properties of the materials were deter...

Nowadays the number of publications regarding the synthesis, characterization, and applications of photocatalytic materials for environmental remediation has increased exponentially, since the use of these materials might lead to the development of sustainable technology that allows cleaning the environment in a safe and effective way. Of particula...

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 results suggest a relationship among physico-chemical properties of each dy...

As previously discussed, there exists interest for the large-scale production of nanostructured materials of bare or doped semiconductor photocatalysts. Numerous reports have been presented regarding the synthesis, characterization, and photocatalytic activity evaluation of undoped and doped (metal or nonmetal) titanium dioxide, for example. It has...

Semiconducting materials are of great technological importance in electronics industry and environmental remediation due to their ability to generate charge carriers when activated with certain energy. The favorable combination of electronic structure, light absorption properties, charge transport characteristics, and excited lifetimes of some semi...

This critical volume examines the different methods used for the synthesis of a great number of photocatalysts, including TiO2, ZnO and other modified semiconductors, as well as characterization techniques used for determining the optical, structural and morphological properties of the semiconducting materials. Additionally, the authors discuss pho...

This critical volume examines the different methods used for the synthesis of a great number of photocatalysts, including TiO2, ZnO, and other modified semiconductors, as well as characterization techniques used for determining the optical, structural and morphological properties of the semiconducting materials. Additionally, the authors discuss ph...

Based on our previous work on the green preparation of Ag–TiO2 photocatalyst with bactericidal activity under visible light, we extended our studies to the synthesis of TiO2–Fe3+ materials with enhanced photocatalytic activity for the degradation of recalcitrant organic pollutants in water. TiO2–Fe3+ nanopowders were synthesized using a robust, env...

The goal of this research is to find a more effective treatment for tequila vinasses (TVs) with potential industrial application in order to comply with the Mexican environmental regulations. TVs are characterized by their high content of solids, high values of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), low pH and intense colou...

In this manuscript, we present a computational model to approximate the solutions of a partial differential equation which describes the growth dynamics of microbial films. The numerical technique reported in this work is an explicit, nonlinear finite-difference methodology which is computationally implemented using Newton's method. Our scheme is c...

In this work, we introduce a numerical method to approximate the solutions of a multidimensional parabolic partial differential equation with nonlinear diffusion and reaction, subject to nonnegative initial data and homogeneous boundary conditions of the Neumann type. The equation considered is a model for both the growth of biological films and th...

The reaction of R3M (M=Ga, In) with HESiR′3 (E=O, S; R′3=Ph3, iPr3, Et3, tBuMe2) leads to the formation of (Me2GaOSiPh3)2(1); (Me2GaOSitBuMe2)2(2); (Me2GaOSiEt3)2(3); (Me2InOSiPh3)2(4); (Me2InOSitBuMe2)2(5); (Me2InOSiEt3)2(6); (Me2GaSSiPh3)2(7); (Et2GaSSiPh3)2(8); (Me2GaSSiiPr3)2(9); (Et2GaSSiiPr3)2(10); (Me2InSSiPh3)3(11); (Me2InSSiiPr3)n(12), in...

Motivated by a recent report by R. E. Mickens, we design an effi-cient, non-standard, two-step, nonlinear, explicit, exact finite-difference method to approximate solutions of a population equation with square-root reaction law. Mickens' report establishes the existence of non-negative, traveling-wave solutions of that model which are bounded from...

This communication reports on some incorrect simulations obtained via an implementation of the method introduced in [Int. J. Comput. Meth. 9 (2012) 1250050]. In the present note, we show the correct numerical results of Example 6.1 in that work. A new computer experiment is added in order to observe the process of merging colonies in biological fil...

In this work, we present a simple, finite-difference method to approximate positive and bounded solutions of a parabolic partial differential equation with nonlinear diffusion, which describes the growth dynamics of colonies of bacteria. A theorem on the existence and uniqueness of positive and bounded solutions of the model considered is available...

Synthetic polymers are growing environmental concern because they are generally nondegradable and recent research has been focused on the biological treatment of plastic wastes and the development of biodegradable plastics. Plastics are classified into two broad types: thermoplastics and thermosetting plastics. Phenol–formaldehyde resins (PF resins...

Synthetic polymers are growing environmental concern because they are generally nondegradable and recent research has been focused on the biological treatment of plastic wastes and the development of biodegradable plastics. Plastics are classified into two broad types: thermoplastics and thermosetting plastics. Phenol-formaldehyde resins (PF resins...

Synthetic polymers are growing environmental concern because they are generally nondegradable and recent research has been focused on the biological treatment of plastic wastes and the development of biodegradable plastics. Plastics are classified into two broad types: thermoplastics and thermosetting plastics. Phenol-formaldehyde resins (PF resins...

Engineered noble (silver [Ag], gold [Au], and platinum [Pt]) metallic nanoparticles (ENPs) were prepared in gum arabic solutions using a facile, economical, and nontoxic synthetic route. Advanced instrumentation techniques (ultraviolet-visible spectroscopy, X-ray powder diffraction, high-resolution transmission electron microscopy equipped with X-r...

We report the synthesis of grafted copolymers of acrylonitrile (AN) and vinyl acetate (AV) on starch (St) (PAN-g-St) using graft copolymerization methods in solution under air presence. The grafting reactions were initiated by free radical methods using ammonium persulfate (APS) and sodium bisulfate (SB) as an initiators. We have found that the gra...

Fundamental research has been carried out to define optimal "green" synthesis conditions for the production of titania (TiO(2)) and silver (Ag) nanocomposites (TANCs) ranging from 12.7-22.8 nm in diameter. A bottom-up colloidal approach was employed to accurately control TANC monodispersity and composition. TANCs were found to be effective at inact...

En este estudio, copolímeros injertados de almidón (ALM) con acrilonitrilo (AN) y acetato de vinilo (AV) (PAN-co-ALM) fueron preparados mediante métodos de copolimerización injertada en solución bajo una atmósfera oxidante normal (en presencia de aire). Las reacciones de injerción fueron iniciadas por procesos de radicales libres, empleando persulf...

Platinum (Pt) is the most efficient and highly utilized electrocatalsyt; however its high cost hinders its widespread use as a stand-alone catalyst. To remedy this problem, a nickel (Ni) encapsulated by Pt (NiⓔPt) nanocatalyst was fabricated using a cost-effective green colloidal method. The NiⓔPt nanoparticles (NPs) were then characterized using t...

An environmental-friendly procedure for manufacturing silver (Ag) and titania (TiO(2)) nanocomposites in an aqueous solution is presented. This green synthetic approach results in the successful production of nanomaterials with high dispersion and crystallinity. The colloidal suspensions of the nanocomposites composed of metal and ceramic (Ag-TiO(2...

A significant accomplishment of this study centers on developing nanocomposite materials via green synthesis techniques for inactivation of prokaryotes like Escherichia coli (E coli). The motivations of this study are to: (1) implement fundamental research in nanochemistry for biological application; (2) understand the mechanism(s) of inactivation...

The fabrication and characterization of gold (Au) nanostructured materials draws significant attention because of their distinctive properties and their technological applications. The first objective of this study is to fabricate polymer-stabilized Au nanoparticles and nanofilms (PAN) through a cost effective and green synthetic methodology. In th...

The nonlinear phenomena of supratransmission and bistability in harmonically forced arrays of anharmonic oscillators are studied in the present article. Employing a finite-difference scheme with multiple properties of consistency, we show that these processes are actually present in such nonlinear systems. We show that, for every frequency in the f...

The title compound, [Zn3(C9H21SiS)6] or [(ⁱPr3SiS)Zn(μ-SSiⁱPr3)2Zn(μ-SSiⁱPr3)2Zn(SSiⁱPr3)], is the first structurally characterized homoleptic silanethiol­ate complex of zinc. A near-linear arrangement of three ZnII ions is observed, the metals at the ends being three-coordinate with one terminally bound silanethiol­ate ligand. The central ZnII ion...

In the present work, the connection of the generalized Fisher–KPP equation to physical and biological fields is noted. Radially symmetric solutions to the generalized Fisher–KPP equation are considered, and analytical results for the positivity and asymptotic stability of solutions to the corresponding time-independent elliptic differential equatio...

In this work, we show that an adequate modulation of the driving amplitude in an anharmonic chain results in an efficient transmission of binary information. The non-linear processes of supratransmission and infratransmission are shown to be useful in the solution of the problem under investigation. Numerical results are conducted using a finite-di...

We present an implicit finite-difference scheme to approximate solutions of generalized α-Fermi–Pasta–Ulam systems defined on bounded domains which, amongst other features, include the presence of external and internal damping. Both continuous and semi-discrete media are considered in this paper, and several other scalar parameters are considered i...

Silver nanoparticles (Ag-NPs) were synthesized using a facile green chemistry synthetic route. The reaction occurred at ambient temperature with four reducing agents introduced to obtain nanoscale Ag-NPs. The variables of the green synthetic route, such as acidity, concentration of starting materials, and molar ratio of reactants were optimized. Di...

It has been reported that potassium dichromate-induced nephrotoxicity is evidenced by diminution in creatinine clearance, increase in urinary protein, and structural damage to the proximal tubules. Damage to tissue often leads to the release of enzymes from the injured cells into the extracellular fluids. The aim of this study was to establish whet...

It is well known that exposure to chromium (Cr) can lead to nephrotoxicity. Quercetin is a flavonoid of interest because of its proposed health-promoting effects. The aim of this work was to elucidate the role of quercetin against the nephrotoxicity caused by Cr in rats. Quercetin may have positive effects in combating, or helping to prevent, nephr...

La técnica de rotación se emplea ampliamentepara el depósito de películas delgadas de diversos materiales. Se diseñó y construyó un aparato doméstico para el depósito de películas delgadas basado en el método de rotación. El equipo es compacto y ofrece un control digital, amplio rango de velocidades (desde 1 hasta 7500 rpm),estabilidad, etc. Para l...

The mol­ecule of the title compound, C30H46, has a crystallographically imposed inversion center and the cyclo­hexyl groups are oriented with their methine H atoms pointing towards one another (H⋯H = 1.99 Å). The cyclohexyl groups adopt chair conformations. A significant C—H⋯π inter­action assembles mol­ecules into layers parallel to (100).

The mol­ecule of the title compound, C30H46, has a crystallographically imposed inversion center and the cyclo­hexyl groups are oriented with their methine H atoms pointing towards one another (H⋯H = 2.04 Å).

The title compound, C24H25Br, packs efficiently in the crystal structure with no solvent-accessible voids and several intermolecular H...H contacts approximating the sum of the van der Waals radii. The molecule is quite crowded, with intramolecular Br...H and C...H contacts ca 0.38 and 0.30 Å, respectively, less than the sum of the corresponding va...

The molecule of the title compound, C30H46, has a crystallographically imposed inversion center and the cyclohexyl groups are oriented with their methine H atoms pointing towards one another (H...H = 1.99 Å). The cyclohexyl groups adopt chair conformations. A significant C—H...π interaction assembles molecules into layers parallel to (100).

The molecule of the title compound, C30H46, has a crystallographically imposed inversion center and the cyclohexyl groups are oriented with their methine H atoms pointing towards one another (H...H = 2.04 Å).

The title compound, C24H25Br, packs efficiently in the crystal structure with no solvent-accessible voids and several inter­molecular H⋯H contacts approximating the sum of the van der Waals radii. The mol­ecule is quite crowded, with intra­molecular Br⋯H and C⋯H contacts ca 0.38 and 0.30 Å, respectively, less than the sum of the corresponding van d...

The copper silanechalcogenolates tBu3PCuESiPh3 (1, E = O; 2, E = S; 3, E = Se) were prepared from the reaction of [tBu3PCu(CH3CN)3]BF4 with [Ph3SiELi(THF)2]2 in acetonitrile. The compounds were obtained as colorless, crystalline, but thermally labile solids. X-ray crystallography shows that complexes 1-3 are monomeric in the solid state with no Cu....

Bis(triphenyl­silyl)selenide, [(C6H5)3Si]2Se or C36H30SeSi2, exists in the solid state as monomeric angular mol­ecules. Si—Se—Si angles of 111.56 (3) and 109.45 (3)° are found in the two independent mol­ecules.

The title compound, [Cu4I4(C12H27P)4], recovered from an attempt to prepare triisopropyl­silylthiol­ato(tri-tert-butyl­phosphine)copper(I), is found to be tetra­meric with a distorted heterocubane structure, one of the body diagonals of the cube being a crystallographic threefold rotation axis.

New single source precursors to hexagonal gallium sulfide (GaS) were investigated. Four organometallic compounds containing a Ga2S2 ring core, [R2Ga(μ-SSiR′3)]2 (R=Me, Et; R′=Ph, iPr), were prepared and thermally decomposed to give chemically pure gallium sulfide. The decomposition temperatures as measured by TGA range from 200 to 350°C and the res...

Universitaria C.P. 20100 Aguascalientes, Ags. México, fax (449)9108410, 2 IBT-UNAM, 3 CINVESTAV IPN jjaureg@correo.uaa.mx Palabras clave: resinas fenólicas, hongos ligninoliticos, biodegradación. Introducción. Las resinas fenólicas (RF) o baquelita son duroplásticos que se obtienen mediante la condensación de fenol y formaldehído en condiciones alc...