Additive synthesis by sol-gel method for its use as antimicrobial

The antimicrobial activity of silver nanoparticles makes this chemical element attractive for their incorporation in different materials. Additionally, heteropolyacids (HPAs) have advantages as catalysts which make them environmentally very interesting. The objective of this work is to incorporate in a silica matrix obtained by sol-gel an HPA together with Ag, for their use as fillers in paints or adhesives. Six samples were synthesized, using tetraethoxysilane, methyltrimethoxysilane, acetic acid, molybdophosphoric acid and silver acetate. The silicas were characterized by potentiometric titration, XRD, SEM, TEM, SBET and FT-IR. When HPA is used instead of acetic acid, a variation on the final acidity is produced. The specific surface area decreases when HPA is incorporated into the silica synthesized using tetraethoxysilane as precursor, noticing a slight increase when Ag is added because a different distribution of HPA in the matrix. By SEM, it was observed that the particle size is bigger when the silicas are synthesized with TEOS-HPA, but it still shows the characteristic morphology of bulk silica. Additionally, preliminary test to evaluate the antimicrobial properties of the solids were carried out with fungi as Chaetomium globosum and Alternaria alternate, isolated from contaminated paints, and the first results are encouraging to continue with the development of these materials.Fil: Arreche, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; ArgentinaFil: Hernández, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; ArgentinaFil: Blanco, Mirta Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; ArgentinaFil: Vazquez, Patricia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; Argentin

Trophic analysis and parasitological aspects of liolaemus parvus (Iguania: Liolaemidae) in the central andes of Argentina

The objective of this study was to describe temporal variations in the diet and parasitological aspects in Liolaemus parvus. In order to examine the diet, we determined the volume, numerousness, and frequency of occurrence for each prey item and calculated the relative importance index. We removed nematodes from the stomach and estimated parasitic indicators. Liolaemus parvus presents an active searching mode. It is a predominantly insectivorous species with low intake of plant material and a specialist in feeding on prey items of the family Formicidae, although it also feeds on other arthropods like coleopterans, hemipterans, and spiders. We found temporal variations in its diet. The first record of Parapharyngodon riojensis nematodes is reported herein. Males showed higher nematode prevalence than females. We have expanded the number of host species and the distribution range of Parapharyngodon riojensis. The information provided about trophic ecology and parasitism is the first contribution to this lizard species’ biology.Fil: Castillo, Gabriel Natalio. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Acosta, Juan Carlos. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; ArgentinaFil: Blanco, Graciela Mirta. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentin

Adjustment of the reproductive activity of vulnerable lizard phymaturus williamsi at high altitudes

In environments with cold climates, reproduction of lizards is restricted to short seasonal periods of activity, from mid-spring to early autumn. We studied the reproductive biology of Phymaturus williamsi (William’s Andean Lizard), a vulnerable and viviparous lizard from the palluma phylogenetic group of genus Phymaturus, endemic to rocky outcrops in cold environments in the Andes of San Juan, Argentina. We determined adult size, male and female reproductive cycles, litter size, mean annual reproductive output, and the relationship between gonadal cycles, fat bodies, and climatic variables. The shortest reproductive male and female were 87.2 mm and 86.4 mm SVL, respectively. The litter size per female was of one or two offspring every two years, and the mean annual reproductive output was 0.95 offspring/female/year. Births occurred from late summer to early autumn. Males exhibited an annual postnuptial cycle, with spermatogenesis beginning in mid-spring, spermiogenesis occurring in summer and autumn, and sperm stored during brumation through early spring when mating occurs. The male post-nuptial cycle is common in species of the patagonicus group, but not in the palluma group, as is P. williamsi. Nevertheless, the biennial female cycle is common in the palluma group, and results from the adjustment of the reproductive activity to the physiological and environmental constraints of the harsh and cold climatic conditions prevailing at high altitudes in the Andes. The knowledge of the reproductive traits of the vulnerable P. williamsi has direct relevance for the development of conservation strategies, as this information is fundamental for population viability analyses.Fil: Castro, Susana Alejandra. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Boretto, Jorgelina Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Blanco, Graciela Mirta. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; ArgentinaFil: Acosta, Juan Carlos. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentin

Additive synthesis by sol-gel method for its use as antimicrobial

The antimicrobial activity of silver nanoparticles makes this chemical element attractive for their incorporation in different materials. Additionally, heteropolyacids (HPAs) have advantages as catalysts which make them environmentally very interesting. The objective of this work is to incorporate in a silica matrix obtained by sol-gel an HPA together with Ag, for their use as fillers in paints or adhesives. Six samples were synthesized, using tetraethoxysilane, methyltrimethoxysilane, acetic acid, molybdophosphoric acid and silver acetate. The silicas were characterized by potentiometric titration, XRD, SEM, TEM, SBET and FT-IR. When HPA is used instead of acetic acid, a variation on the final acidity is produced. The specific surface area decreases when HPA is incorporated into the silica synthesized using tetraethoxysilane as precursor, noticing a slight increase when Ag is added because a different distribution of HPA in the matrix. By SEM, it was observed that the particle size is bigger when the silicas are synthesized with TEOS-HPA, but it still shows the characteristic morphology of bulk silica. Additionally, preliminary test to evaluate the antimicrobial properties of the solids were carried out with fungi as Chaetomium globosum and Alternaria alternate, isolated from contaminated paints, and the first results are encouraging to continue with the development of these materials.Centro de Investigación y Desarrollo en Ciencias Aplicada

Síntesis de sílice mediante el método sol-gel y su aplicación como aditivos antimicrobianos en pinturas higiénicas

El poder antimicrobiano de las nanopartículas de plata hace a este elemento muy atractivo para incorporarlo a diversos materiales. Asimismo, los heteropoliácidos (HPAs) poseen ventajas como catalizadores y son ambientalmente atractivos. Este trabajo tiene como objetivo incorporar en una matriz silícea obtenida por sol-gel un heteropoliácido junto con Ag, para emplearlo como aditivo en pinturas y/o adhesivos. Se sintetizaron 6 muestras, utilizando TEOS, MTMS, ácido acético, ácido fosfomolibdico y acetato de plata. Los materiales se caracterizaron por titulación potenciométrica, DRX, SEM, SBET y FT-IR. Cuando se usa HPA reemplazando el ácido acético se produce una variación en la acidez final. El área disminuye cuando se incorpora HPA para TEOS, pero tiene un leve aumento cuando se adiciona Ag por diferente distribución del HPA en la matriz. Por SEM, el tamaño de las partículas es mayor cuando las sílices son sintetizadas con TEOS-HPA, observándose la morfología característica de la sílice másica.The antimicrobial activity of silver nanoparticles makes this chemical element attractive for their incorporation in different materials. Additionally, heteropolyacids (HPAs) have advantages as catalysts which make them environmentally attractive. The objective of this work is to incorporate in a silicium matrix obtained by sol-gel an HPA together with Ag for their use as fillers in paints or adhesives. Six samples were synthesized, using TEOS, MTMS, acetic acid, phosphomolybdic acid and silver acetate. The silicas were characterized by potentiometric titration, XRD, SEM, TEM, SBET and FT-IR. When HPA is used instead AAc, a variation on final acidity is produced. The specific surface area decreases when HPA is incorporated on TEOS-silica, noticing a slight increase when Ag is added because a different distribution of HPA on the matrix. By SEM, the particles size is bigger when the silicas are synthesized with TEOS-HPA, but it still shows the characteristic morphology of bulk silica.Centro de Investigación y Desarrollo en Ciencias Aplicada

Improved antimicrobial activity of silica-Cu using a heteropolyacid and different precursors by sol-gel: synthesis and characterization

Antimicrobial coatings are used to avoid the proliferation of fungi and bacteria inside urban buildings by incorporating low concentrations of antimicrobial agents (biocides). This study is focused on evaluating the antifungal activity of copper (II) supported on a silica matrix, and as counter-cation of a heteropolyacid, obtained from the sol-gel method using various catalysts, against two fungal isolates. The fungi used in this evaluation were Alternaria alternata and Chaetomium globosum isolated by routine microbiological techniques from biodeteriorated paints films. In all cases, fungi were selected due to their ability to grow on the paint films and their negative impact on human health. First, silicas were prepared using tetraethylorthosilicate and methyl trimethoxysilane as precursors and acetic acid, hydrochloric acid as catalysts of the hydrolysis reaction of the alkoxide. The effect of addition of copper (II) in the form of copper nitrate was studied. With respect to the morphology of the silica, most of them are similar, between pure and modified silica, in all cases. Once the stage of the synthesis and characterization of the prepared materials was performed, six of them were selected to evaluate their antifungal activity by agar plate inhibition test against both fungi of interest (A. alternata and C. globosum), and the percent inhibition was determined in each case. Tested Cu-based solids were shown to have a higher antifungal activity because they completely inhibit the growth of both fungi with lower concentrations relative to its control. This work was performed as a preliminary study, in order to guide the selection of a suitable organic biocide from a list of possible antifungal agents.Centro de Investigación y Desarrollo en Tecnología de Pintura

Synthesis and characterization of zirconium oxides for use as antimicrobial additives in paints

Zirconia is a multifunctional material widely used. Its important properties such as high chemical resistance, thermal stability and high mechanical toughness have turned these materials into object of study within fields such as the optics, electronics, magnetism, among others. In recent years, the chemical properties of zirconium oxide have been used, mixed with silicon in order to obtain mixed oxides, more stable and robust, with the final application on toughening of ceramics. These properties are related to the degree of mixing of the components at molecular level, therefore, the linking between Si-O-Zr. Considering the effective antimicrobial capacity of silver nanoparticles, their incorporation into different materials is very interesting, acting as biocides. The objective of this work is to obtain zirconium oxides by the sol-gel technique, using zirconium n-propoxide as precursor, and also study the effect of different solvents (water:ethanol), the use of various acid catalysts in the synthesis, acetic acid and a heteropolyacid (HPA), as the phosphomolybdic acid (H3PMo12O40), in the physicochemical properties of the obtained solids. Finally, the addition of a silver salt was carried out into the sample with acetic acid and heteropolyacid as catalyst in order to incorporate it as antimicrobial filler in paints. The obtained materials were characterized by SEM, XRD, FT-IR, textural properties through the absorption of N2 (SBET) and potentiometric titration with n-butylamine. Homogeneous solids were obtained in all the synthesis with acetic acid as catalysts. In addition, x-ray diffraction diagrams of amorphous solids were observed. The values obtained of surface areas are influenced by the variables of synthesis. The characteristic bands of zirconia were observed by FTIR in the solids synthesized. The results show that the solids environmentally synthesized are promising additives for use in paints.Centro de Investigación y Desarrollo en Tecnología de PinturasCentro de Investigación y Desarrollo en Ciencias Aplicada

Primer registro de <i>Ameivula abalosi</i> Cabrera, 2012 (Squamata: Teiidae) en la provincia de San Juan, Argentina

Se informa el primer registro de Ameivula abalosi (Cabrera, 2012) para la provincia de San Juan, departamento Valle Fértil. Así, se proporciona nueva información a los inventarios de la biodiversidad herpetofaunística de la Reserva de Usos Múltiples Valle Fértil y para la provincia de San Juan.Asociación Herpetológica Argentina (AHA

Amphisbaena bolivica Mer tens, 1929 (Squamata: Amphisbaenidae): Primer registro para la provincia de San Juan, Argentina

Durante un estudio de campo correspondiente a un monitoreo herpetofaunístico en la localidad de Valle Fértil, se registró un ejemplar de A. bolivica (LHC= 275 mm). Fue identificado siguiendo los caracteres diagnósticos y merísticos de la especie (Montero, 1996b; Vanzolini, 2002; Fig. 2).Asociación Herpetológica Argentin

Primer registro de <i>Ameivula abalosi</i> Cabrera, 2012 (Squamata: Teiidae) en la provincia de San Juan, Argentina

Se informa el primer registro de Ameivula abalosi (Cabrera, 2012) para la provincia de San Juan, departamento Valle Fértil. Así, se proporciona nueva información a los inventarios de la biodiversidad herpetofaunística de la Reserva de Usos Múltiples Valle Fértil y para la provincia de San Juan.Asociación Herpetológica Argentina (AHA