Adipose mesenchymal stem cells in the field of bone tissue engineering.

Bone tissue engineering represents one of the most challenging emergent fields for scientists and clinicians. Current failures of autografts and allografts in many pathological conditions have prompted researchers to find new biomaterials able to promote bone repair or regeneration with specific characteristics of biocompatibility, biodegradability and osteoinductivity. Recent advancements for tissue regeneration in bone defects have occurred by following the diamond concept and combining the use of growth factors and mesenchymal stem cells (MSCs). In particular, a more abundant and easily accessible source of MSCs was recently discovered in adipose tissue. These adipose stem cells (ASCs) can be obtained in large quantities with little donor site morbidity or patient discomfort, in contrast to the invasive and painful isolation of bone marrow MSCs. The osteogenic potential of ASCs on scaffolds has been examined in cell cultures and animal models, with only a few cases reporting the use of ASCs for successful reconstruction or accelerated healing of defects of the skull and jaw in patients. Although these reports extend our limited knowledge concerning the use of ASCs for osseous tissue repair and regeneration, the lack of standardization in applied techniques makes the comparison between studies difficult. Additional clinical trials are needed to assess ASC therapy and address potential ethical and safety concerns, which must be resolved to permit application in regenerative medicine

Satureja montana: evaluación como agente antifúngico en pinturas para prevención del biodeterioro

El biodeterioro constituye un conjunto de procesos físicos y químicos que generan alteraciones en diversos materiales. La prevención del crecimiento de mohos, así como el desarrollo de medidas de tratamiento apropiadas para los objetos contaminados, son un desafío permanente [1,2]. En este sentido, las pinturas y recubrimientos en general juegan un papel importante como sistemas de conservación y protección de los distintos objetos. El objetivo de este trabajo de investigación fue, en una primera instancia, evaluar la actividad antifúngica in vitro del aceite esencial de Satureja montana (Sm) para luego incorporarlo en una formulación de pintura látex como agente biocida y evaluar su desempeño. Mediante ensayos de contacto in vitro con distintos hongos, se determinó que el aceite esencial al 0.5% v/v, inhibió completamente el crecimiento de todos los hongos. Posteriormente, se formuló una pintura al agua a la que se incorporó como aditivo biocida Sm al 2% p/p y se realizó el ensayo de bioresistencia de la película seca. Para ello, se inocularon paneles pintados con Aspergillus sp. y se incubaron en atmósfera de humedad controlada. Al finalizar el tiempo de incubación, se realizó una inspección visual asignando una calificación al crecimiento fúngico, según la Norma ASTM D-5590-00. Adicionalmente, se realizaron observaciones mediante microscopia electrónica de barrido (MEB). La pintura con el aceite esencial mostró una inhibición significativa del crecimiento fúngico sobre la película seca.Tópico 5: Conservación y restauración de bienes muebles y piezas (documentos de archivos, pinturas, cueros, maderas, textiles, metales, rocas ornamentales, vitrales, etc.)

Synergism in anticorrosive paints

The present work depicts synergism anticorrosive behaviour between zinc hypophosphite and zinc phosphate in a commercial pigment mixture. Also, the performance of anticorrosive paints was evaluated. Synergism anticorrosive behaviour was evaluated by corrosion potential and linear polarization measurements in pigment suspensions. The protective layer obtained with this pigment mixture was investigated by scanning electron microscopy (SEM). Then, the anticorrosive properties of the pigment were assessed by incorporating it into alkyd and epoxy paints which were evaluated by salt spray test and electrochemical noise technique. The morphology and the nature of the protective layer grown under the paint film were also studied by SEM. Experimental results showed that improved anticorrosion protection is achieved in paints with reduced zinc phosphate contents as a consequence of the synergistic interaction between zinc hypophosphite and the other components of the pigment mixture. The electrochemical noise technique proved to be adequate to monitor corrosion in painted panels and is able to detect corrosion under the paint film from very early stages. This paper identified the need to study synergism between anticorrosive pigments to try to reduce the phosphate content in anticorrosive paints.Centro de Investigación y Desarrollo en Tecnología de Pintura

Synergism in anticorrosive paints

The present work depicts synergism anticorrosive behaviour between zinc hypophosphite and zinc phosphate in a commercial pigment mixture. Also, the performance of anticorrosive paints was evaluated. Synergism anticorrosive behaviour was evaluated by corrosion potential and linear polarization measurements in pigment suspensions. The protective layer obtained with this pigment mixture was investigated by scanning electron microscopy (SEM). Then, the anticorrosive properties of the pigment were assessed by incorporating it into alkyd and epoxy paints which were evaluated by salt spray test and electrochemical noise technique. The morphology and the nature of the protective layer grown under the paint film were also studied by SEM. Experimental results showed that improved anticorrosion protection is achieved in paints with reduced zinc phosphate contents as a consequence of the synergistic interaction between zinc hypophosphite and the other components of the pigment mixture. The electrochemical noise technique proved to be adequate to monitor corrosion in painted panels and is able to detect corrosion under the paint film from very early stages. This paper identified the need to study synergism between anticorrosive pigments to try to reduce the phosphate content in anticorrosive paints.Centro de Investigación y Desarrollo en Tecnología de Pintura

The anti-corrosion performance of water-borne paints in long term tests

One of the most inexpensive and effective method to protect steel against corrosion is paints containing active pigments. The traditional way to test these coatings performance is by accelerated tests (exposition to salt spray and/or humidity chambers) and electrochemical tests (corrosion potential, ionic resistance and electrochemical impedance spectroscopy). However, these tests give incomplete information if the results are not correlated to outdoor or service tests. The aim of this work was to evaluate water-borne epoxy anticorrosion paints containing different commercial phosphate pigments. The paints were exposed to a semi-industrial atmosphere for 7 years. Electrochemical tests and accelerated assays were also done in order to find a correlation between laboratory and service tests. The results obtained showed no correlation between those from pigment suspensions and those from painted panels, as it seemed that paint performance is highly dependent on the resin. The pigments zinc iron phosphate and zinc aluminium phosphate performed poorly in pigment suspensions. However, the coatings containing them exhibited the highest ionic resistance, the lowest film capacitance and gave the better results in outdoor tests. Results in outdoor exposure tests correlated with those from impedance measurements.Centro de Investigación y Desarrollo en Tecnología de Pintura

The anti-corrosion performance of water-borne paints in long term tests

One of the most inexpensive and effective method to protect steel against corrosion is paints containing active pigments. The traditional way to test these coatings performance is by accelerated tests (exposition to salt spray and/or humidity chambers) and electrochemical tests (corrosion potential, ionic resistance and electrochemical impedance spectroscopy). However, these tests give incomplete information if the results are not correlated to outdoor or service tests. The aim of this work was to evaluate water-borne epoxy anticorrosion paints containing different commercial phosphate pigments. The paints were exposed to a semi-industrial atmosphere for 7 years. Electrochemical tests and accelerated assays were also done in order to find a correlation between laboratory and service tests. The results obtained showed no correlation between those from pigment suspensions and those from painted panels, as it seemed that paint performance is highly dependent on the resin. The pigments zinc iron phosphate and zinc aluminium phosphate performed poorly in pigment suspensions. However, the coatings containing them exhibited the highest ionic resistance, the lowest film capacitance and gave the better results in outdoor tests. Results in outdoor exposure tests correlated with those from impedance measurements.Centro de Investigación y Desarrollo en Tecnología de Pintura

Protección del acero con pinturas con sales de tierras raras como pigmentos anticorrosivos

Entre las estrategias desarrolladas para proteger estructuras metálicas de la corrosión en el medio en el que serán expuestas se destacan las pinturas. El objetivo de este trabajo fue evaluar el comportamiento de pinturas anticorrosivas conteniendo sales de tierras raras (STR) como inhibidores de corrosión para proteger el acero de la oxidación. Se propone el uso de zeolitas modificadas con iones pasivantes como el Ce (III) como pigmentos anticorrosivos, debido a que el uso del fosfato de zinc ha comenzado a restringirse por su impacto negativo en el medio ambiente. La capacidad de intercambiar iones, las características de adsorción y su reactividad hace que este grupo de silicatos sea interesante desde el punto de vista de la tecnología de los recubrimientos anticorrosivos inteligentes. El efecto protector del acero de las soluciones de nitrato de cerio (III) a distintas concentraciones fue evaluado mediante técnicas electroquímicas. La película protectora formada sobre el metal expuesto fue observada mediante microscopía electrónica de barrido (MEB). Las pinturas formuladas con las zeolitas modificadas fueron aplicadas sobre paneles de acero SAE 1010 arenados. La capacidad protectora de los recubrimientos fue evaluada observando el grado de corrosión según la norma ASTM D 610 mediante la exposición en cámara de niebla salina (ASTM B117). Los recubrimientos formulados también se evaluaron por espectroscopía de impedancia electroquímica. Los resultados obtenidos mostraron que es posible reemplazar hasta 2/3 del contenido de fosfato de cinc en las pinturas anticorrosivas por zeolita modificada con iones cerio, sin pérdida significativa de las propiedades anticorrosivas

Development of green hygienic coating based on essential oil microcapsules

The challenges for developing new materials are accomplishing more functionality with less material due to the increasing efficiencies of the smart approaches. In this sense, the coating technology based on the incorporation of microcapsules has emerged recently as a strategy in the advance of protective and functional materials, promising an environmentally friendly approach. Microbial colonization of painted surfaces is a major concern because it shortened the useful life of the coating by discoloration and degradation. Besides there is a great concern about the indoor microbial colonization especially in places that should have high standards of environmental hygiene as in the food industry and those related to human health-care. The aim of this work is to develop a novel green antifungal water-borne paint formulated with melamine-formaldehyde (MF) microcapsules containing essentials oil as biocide agent. The microcapsules were synthesized by interfacial polymerization. Melamine-formaldehyde resin was used for the microcapsule shell wall, and two different essential oils (EOs) as core materials. The EOs studied were Tea Tree and Lavandin Abrialis. Microcapsule morphology was examined by Field-Emission Scanning Electron Microscopy (FE-SEM), while their size distributions were determined by light diffraction (LD). Microcapsule composition (shell and core) was analyzed by FTIR-ATR spectroscopy. Preparation of acrylic water-borne paint was done in a high speed disperser. The microcapsules (MF-Tea tree and MFLavandin) were incorporated into the original paint just before used, at 6% by weight of the total paint composition. As negative control a paint without biocide was used. The effectiveness of these microcapsules on paint film was evaluated by plaque inhibition assay. Commercial gypsum boards were used as substrate. Each painted panel was inoculated with 100 μl of the spore suspension of Aspergillus sp. and kept in a culture chamber at 86% relative humidity for 4 weeks. The fungal growth was estimated as a percentage of coverage onto the surface and scored according to ASTM D5590 standard specification. The results obtained in antifungal assay on paint film were promising. According to ASTM D5590, the score obtained by MF-lavandin paint was 1, which indicate just a trace growth onto the painted surface (<10%). On the other hand, the control and MF-Tea tree paints obtained the same score: 4 points, the highest qualification (fungal growth >70%). Comparing those results, it can be seen that Aspergillus sp. growth reduction was significant when MF-lavandin paint was used, suggesting that those microcapsules had an inhibitive activity on the dry film whereas MF-Tea tree had not such activity.Centro de Investigación y Desarrollo en Tecnología de Pintura

Development of green hygienic coating based on essential oil microcapsules

The challenges for developing new materials are accomplishing more functionality with less material due to the increasing efficiencies of the smart approaches. In this sense, the coating technology based on the incorporation of microcapsules has emerged recently as a strategy in the advance of protective and functional materials, promising an environmentally friendly approach. Microbial colonization of painted surfaces is a major concern because it shortened the useful life of the coating by discoloration and degradation. Besides there is a great concern about the indoor microbial colonization especially in places that should have high standards of environmental hygiene as in the food industry and those related to human health-care. The aim of this work is to develop a novel green antifungal water-borne paint formulated with melamine-formaldehyde (MF) microcapsules containing essentials oil as biocide agent. The microcapsules were synthesized by interfacial polymerization. Melamine-formaldehyde resin was used for the microcapsule shell wall, and two different essential oils (EOs) as core materials. The EOs studied were Tea Tree and Lavandin Abrialis. Microcapsule morphology was examined by Field-Emission Scanning Electron Microscopy (FE-SEM), while their size distributions were determined by light diffraction (LD). Microcapsule composition (shell and core) was analyzed by FTIR-ATR spectroscopy. Preparation of acrylic water-borne paint was done in a high speed disperser. The microcapsules (MF-Tea tree and MFLavandin) were incorporated into the original paint just before used, at 6% by weight of the total paint composition. As negative control a paint without biocide was used. The effectiveness of these microcapsules on paint film was evaluated by plaque inhibition assay. Commercial gypsum boards were used as substrate. Each painted panel was inoculated with 100 μl of the spore suspension of Aspergillus sp. and kept in a culture chamber at 86% relative humidity for 4 weeks. The fungal growth was estimated as a percentage of coverage onto the surface and scored according to ASTM D5590 standard specification. The results obtained in antifungal assay on paint film were promising. According to ASTM D5590, the score obtained by MF-lavandin paint was 1, which indicate just a trace growth onto the painted surface (<10%). On the other hand, the control and MF-Tea tree paints obtained the same score: 4 points, the highest qualification (fungal growth >70%). Comparing those results, it can be seen that Aspergillus sp. growth reduction was significant when MF-lavandin paint was used, suggesting that those microcapsules had an inhibitive activity on the dry film whereas MF-Tea tree had not such activity.Centro de Investigación y Desarrollo en Tecnología de Pintura

Evaluación de extractos vegetales como agentes antifúngicos para pinturas

Los diversos materiales con valor histórico y cultural están expuestos al biodeterioro como consecuencia del ataque microbiológico. Para preservarlos se utilizan, muchas veces, recubrimientos y/o pinturas que contienen agentes activos llamados biocidas cuya finalidad es la de prevenir la colonización por parte de los microorganismos. Entre los microorganismos considerados más deteriorantes se encuentran los hongos que, además de manchar las paredes y degradar los materiales expuestos, afectan también la salud humana. En la actualidad es materia de estudio el reemplazo de los biocidas comerciales por otros que presenten un menor impacto ambiental, particularmente los obtenidos a partir de productos naturales. En tal sentido, en el presente trabajo se evaluó la actividad antifúngica, en forma preliminar, de cinco productos vegetales comerciales: dos taninos extraidos de: tara y quillaja y tres aceites esenciales: de pino, del árbol de té y de romero; con el objetivo de seleccionar los más eficientes para ser utilizados, en una etapa posterior, en la elaboración pinturas protectoras. La actividad antifúngica se evaluó frente a dos hongos Alternaria alternata y Chaetomium globosum mediante el ensayo de inhibición en placa. Los hongos aislados fueron obtenidos de películas de pinturas biodeterioradas, según un procedimiento descripto en un trabajo previo