Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The skin recovery (wound healing) properties of materials based on polyvinyl alcohol (PVA) doped with metal nanoparticles (PVA-MNPs) and their chemical and physical characterization is reported. The synthesis of copper and silver metal nanoparticles supported in PVA was performed by Solvated Metal Atom Dispersed (SMAD) method using 2-ethoxyethanol as solvent. The average size of metal nanoclusters (PVA-Cu = 77 nm,  PVA-Ag = 72 nm) was determined by TEM and the distribution of the inorganic phase in the hybrid material was analyzed by SEM-EDX. TGA performed in synthetic air atmosphere shows an improvement in the thermal stability by addition of nanometals to pure polymer, with the copper composite showing a higher thermo resistive capacity than the rest. Antibacterial activity against ATCC bacterial strains of Escherichia coli (E.C.), Staphylococcus aureus (S.A.), Staphylococcus epidermidis (S.E.) and Pseudomonas aeruginosa (P.A.) was determined. The silver compound showed antibacterial activity against all tested microorganisms, while the copper compound was active against S.E. Toxicological and wound healing tests were performed in Sprague Dawley rats with infested injuries on the back which were treated with PVA films doped with copper and silver. The recovery of injures infested with S. aureus is reported. This type of material could be used for biomedical applications, such as skin recovery processes in infected wounds or type I and II burns.  

Throughout human history, passive mining residues have increased the levels of heavy metals or metallic trace elements in different environmental matrices. These elements, having the ability to accumulate, generate potentially toxic sites, and sometimes affecting people's health. In Chile, metal mining is concentrated between the Administrative Regions IV and VI. Mine tailings constitute the toxic residues composed of heavy metals, which in many occasions are deposited in areas neighboring human settlements and are a health hazard for the inhabitants. When the entire mineral is extracted from a copper mine, only 2 % is used; the rest is cast off as different types of waste: 50 % sterile, 44 % tailings and 4 % slag. In this work, the concentrations of metallic trace elements such as: Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Zn were studied in 6 sites of the largest tailings located within Andacollo city, Northern Chile. The sampling points were recorded using GPS geographic coordinates and, in the laboratory, they were characterized determining: pH, electrical conductivity, soluble organic carbon, total organic carbon, available phosphorus, boron, total nitrogen and capacity cation exchange. The concentrations of metallic trace elements in the tailings were quantified through the analysis of two of its fractions, total fraction and soluble fraction. Metals in both fractions ware determined by atomic absorption spectrophotometry (AAS). The physicochemical characterization of the tailings allowed establishing a profile of the environmental conditions of the sampled sites. The sites that presented a higher concentration of metals in the total fraction correspond to sites 4 and 6, while the sites that presented a higher concentration of metals in the labile fraction correspond to sites 2 and 6. Cu, Hg and Mo where the metals with the mayor Environmental risks assessment in all of sites.    

Fenton reagent is known for over a hundred years and the role of homogeneous and heterogeneous Fenton degradation in wastewater treatment in removing recalcitrant organic contaminants is well appreciated and extensively explored. Limitations and shortcomings of homogeneous and heterogeneous Fenton degradation hinder the large-scale application of heterogeneous Fenton reactions in environmental remediation. Thus, the development of Fenton-like reagents is considered as a need of the hour. Most of the drawbacks of Fenton degradation have been taken care of by these novel reagents were dramatically increased catalytic degradation rate of contaminants was observed due to high surface area. Good mechanical stability, improved electron transfer, magnetically separability, and the possibility of widening the scope are the additional features of Fenton-like reagents. In this review, recent trends in the synthesis, strategies for enhancing its catalytic activity, and various applications of heterogeneous Fenton-like catalysts for the abatement of organic pollutants are discussed. This review describes the recent development of other transition metals, Graphene oxide/Carbon/CNT, MIL/MOF, and oxides as Fenton like catalysts in environmental remediation procedures even at ambient conditions.      This review aims to encourage the fabrications of novel and efficient heterogeneous Fenton-like systems and assist the readers in the selection of the best suitable Fenton-like systems for industrial applications by unfolding the various properties and applications of these catalysts.    

In this work, it has been investigated the Monkeypox disease which occurs in both humans and animals by infection with a double-stranded DNA virus having the symptoms consisting of fever, fatigue, headache, and muscle pains like flu. Tecovirimat drug can be applied in prohibition of monkeypox virus through adsorbing onto surface of single-walled carbon nanotube (SWCNT) as the drug delivery method due to direct electron transfer principle which has been studied by density functional theory (DFT) methods. Therefore, it has been accomplished the B3LYP/6-311+G (2d,p) level of theory to estimate the susceptibility of SWCNT for adsorbing tecovirimat through nuclear magnetic resonance and thermodynamic parameters. In other words, the data explained that the feasibility of using SWCNT and tecovirimat becomes the norm in drug delivery system which has been achieved by quantum calculations due to physico-chemical properties of NMR and IR methodologies.

8-(dimethylamino)-N,N-dimethyl­naphthalen-1-aminium hydrogenterephthalate (PSH+TPAH-) and 8-(dimethylamino)-N,N-dimethylnaphthalen-1-aminium hydrogen-terephthalate hydrate (PSH+TPAH-·H2O) were prepared by the direct reaction of N1,N1,N8,N8-tetra­methyl­naphthalene-1,8-di­amine, Proton Sponge (PS) © and terephthalic acid (TPAH2) in a 1:1 stoichiometric relation. The structure of both salts is constructed on the base of 1D chains defined by hydrogen bonding of the anionic carboxylate end and the carboxylic acid of TPAH- anion. Additionally for the structure of PSH+TPAH-·H2O the water molecules connect this 1D chains through hydrogen bonds, then defining a 1D-belt. In both cases the PSH+ provides balance of charge among the chains.

The Mg based composites with the element addition of 3Zn, 0.5Mn and the reinforcement of ceramic particles nanoTiO2 and Al2O3 are added to form an Mg- hybrid composites through powder metallurgy method. The examination is mainly concentrated on the effect of multi ceramic particles such as nanoTiO2 and Al2O3 inclusion in the composite matrix for the characteristics of hardness, tensile strength, wear and corrosion. Optical and scanning electron microscopy are used for the micro structural variation. X-ray diffraction is used to analysis the various phases available in the hybrid composites matrix. Many intermetallic phase are formed during heat treatment process which reduces the porosity and increases density and corrosion resistance of the composites. The hard ceramic particles inclusion, hot extrusion process and heat treatment or stress-relieving mechanism enhances the above said properties of the prepared hybrid composites.  

Teucrium stocksianum is locally used as home remedy in different parts of the world for the treatment of digestive problems as well as microbial infections. The present study was designed to screen phytochemical constituents and in vitro antimicrobial as well as radical scavenging activities of the leaves extracts from the Teucrium stocksianum. Methods: Plant samples of the Teucrium stocksianum were collected from the growing locality and four different solvents viz., n-hexane, methanol, ethanol, and water were used for the preparation of plant extracts. The in vitro biological activities were investigated against eight human pathogens such as like Bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogen, Escherichia coli, Klebsiella pneumoniae and Pseusdomonas aeruginosa and Fungi: Aspergillus niger and Aspergillus fumigatus using agar well diffusion method and minimum inhibitory concentration. The antioxidant properties were carried out by DPPH and reducing power assays using various concentrations. Results: Results revealed that all pathogens were highly susceptible and inhibited by all solvent extracts. The methanolic and ethanolic leaves extracts exhibited promising antimicrobial activity and inhibited the growth of pathogens at par with the standard drugs viz., chloramphenicol for Bacteria and Fluconazole for fungi. Moreover, performance of methanolic and ethanolic extracts was the best amongst all solvents. In terms of antioxidant properties, both methods i.e., DPPH free radicals and reducing power resulted significant activity. Conclusion: The Phytochemical screening and biological activities of Teucrium stocksianum leaves extracts is reported for the first time. The ethanol, methanol, n-hexane and aqueous extracts of Teucrium stocksianum possess significant inhibitory effect against tested pathogens. The present investigation Teucrium stocksianum leaves extract contain potential antimicrobial components that may be of great use for the development of pharmaceutical industries as a therapy against various diseases. These results denote in-depth analysis of methanolic and ethanolic extracts to search potential compound responsible for antimicrobial activity. The results of the study support the folklore claim along with the development of new antimicrobial drugs from the plant. The results showed that Teucrium stocksianum leaves extracts possess multiple essential phytochemicals. Presence of phenolic compounds in plant extract demonstrates antioxidant activity. Both tests for antioxidant properties exhibited marked effects and can be employed as a potential natural antioxidant agent which may be used for mitigating oxidative stress. Nevertheless, there is need to explore mechanism involved for such kind of activity. The current findings hold up the ethno-pharmacological utilization of plant in the treatment of microbial infections and embrace great perception in the development of unusual antimicrobial and antioxidant agents.

Plants are a rich source of secondary metabolites that have been found to have medicinal properties. The present study was conducted to evaluate the phytochemical screening, antimicrobial activities, and heavy metal analysis in different parts (leaves, stem and roots) of Caltha palustris var. alba. The phytochemical analysis for the plant was carried out in ethanol, acetone, ethyl acetate, n-hexane and deionized water extracts. The phytochemical screening confirmed the presence of several bioactive compounds like, alkaloids, flavonoids, tannin, phenols, and saponin. The antimicrobial activity was determined by the agar disc diffusion method using five different extracts. The antimicrobial study revealed that the C. palustris var. alba has the ability to fight against the selected microorganism. The phytochemical and biological screenings were correlated with the presence of heavy metals in selected plant C. palustris var. alba. The concentrations of heavy metals were determined by atomic absorption spectrophotometer and revealed the presence of the metals like cadmium, manganese, zinc, copper, lead, and chromium. The metal concentration was compared with the permissible limit set by World Health Organization (WHO) and the result was discussed. From these studies, it is clear that plant C. palustris var. alba can be used for medicinal purposes.

Water is an essential substance to ensure the survival of human beings has been contaminated over the years, which has been reflected in the increase of contamination by substances from industry and domestic waste, deteriorating its quality and turning it into a risk for those who consume it or live in it. However, in recent years the interest of researchers to remedy this problem has led to the study of different techniques applied to remove these contaminants since the traditional methods used in water treatment plants do not satisfactorily fulfill this purpose. Among the contaminants of greatest interest and to which this review is directed are the emerging contaminants, substances at trace level of a large number of chemical compounds of different origin and nature, which accumulate in aquatic environments causing cardiac affections, psychiatric reactions, liver disorders, genetic mutation, ecotoxicological risks as well as bacterial resistance, such as macrolides. These compounds belong to the group of antibiotics used to treat mainly respiratory affections, but whose consumption has increased in the last couple of years due to their possible action for the prevention of contagion or reduction of symptoms in patients with the COVID-19 virus. Therefore, the objective of this review is to compile the techniques used for their removal, such as sonochemical treatment and continuous ozonation, from which removal percentages higher than 70% have been obtained for macrolides such as azithromycin, clarithromycin, and erythromycin, representative drugs of this type of antibiotics, this in order to conduct research and experimental work for the removal with techniques such as polymer-assisted liquid phase retention, ultranofiltration membranes, which have had high percentages of efficiency for different types of antibiotics and thus establish different ways of removal for these contaminants of interest.  

This paper describes the preliminary determination of some element concentration in buckwheat and commercial buckwheat flour determined by ICP-MS. The results indicate how essential and toxic elements added in the soil were absorbed by the buckwheat seeds planted and how the elements concentration of the new seeds was affected by this intentional addition. Results showed limits of detection and quantification range from 0.008 to 1.085 µg/Kg. Correlation coefficients (r) were calculated in the range of 0.9920 to 0.9999. The data obtained described that some elements are far below LOD and LOQ in µg/Kg concentrations in the grains. and that ICP-MS was a very precise method to determinate simultaneously many elements at the same time.