Nanofibras de ZnO produzidas por eletrofiação: síntese, caracterização e atividade fotocatalítica

Nanofibras de ZnO foram produzidas a partir de precursores à base de poli(álcool vinílico) (PVA) e acetato de zinco (AcZn) obtidos por eletrofiação, nas proporções mássicas de PVA/AcZn 1:1; 2:1 e 4:1, e posterior calcinação. Bandas características da ligação Zn-O e de transições eletrônicas do ZnO foram detectadas nos espectros de infravermelho (FTIR) e absorção fotoacústica (PAS) das nanofibras. Picos cristalinos característicos da estrutura wurtzita e fase hexagonal do ZnO foram detectados nos difratogramas de raios-X (DRX) das amostras produzidas. Os valores de energia de gap (Eg) estimados para as nanofibras de ZnO produzidas após calcinação dos precursores PVA/AcZn 1:1; 2:1 e 4:1 foram de 2,95; 3,15 e 3,02 eV, respectivamente, e a área específica (SBET) destas respectivas amostras foi de 25,26 m²/g; 20,95 m²/g e 23,79 m²/g. As imagens de MEV e MET das amostras de ZnO revelaram que após calcinação, a morfologia de fibra foi mantida apenas para aquelas produzidas a partir dos nanofios precursores de PVA/AcZn 1:1 e 4:1. Todas as amostras de ZnO exibiram excelente desempenho fotocatalítico, degradando cerca de 99% do corante Azul de Metileno, em ambos pH 7,0 e 9,0, e após 240 minutos de irradiação UV-visível

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

APPLICATION OF NANOSTRUCTURED IRON OXIDES AS ADSORBENTS AND PHOTOCATALYSTS FOR WASTEWATER POLLUTANT REMOVAL

New techniques for treating wastewater, particularly the removal or degradation of organic pollutants and heavy metals, among other pollutants, have been extensively studied. The use of nanostructured iron oxides as adsorbent and photocatalyst for the removal of these contaminants has proved a promising approach, not only because of their high treatment efficiency, but also for their cost-effectiveness, having the flexibility for in situ and ex situ applications. In this review, we briefly introduced the most used kinds of iron oxide nanoparticles, some synthesis techniques for iron oxide nanostructure formation, their potential benefits in environmental clean-up, and their recent advances and applications in wastewater treatment. These advances range from the direct applications of synthesized nanoparticles as adsorbents for removing toxic contaminants or as catalysts to oxidize and break down noxious contaminants (including bacteria and viruses) in wastewater, to integrating nanoparticles into conventional treatment technologies, such as composite photocatalytic filters (membranes, sand and ceramic) that combine separation technology with photocatalytic activity. Finally, the impact of nanoparticles on the environment and human health is briefly discussed

Phosphated guar gum: potential ingredient in the development of ethylcellulose isolated films

O uso de polissacarídeos tem atraído grande atenção no desenvolvimento de novos sistemas para liberação específica de fármacos. Esses polímeros estão disponíveis em abundância, a baixo custo, apresentando uma variedade de estruturas e propriedades, podendo ser facilmente modificados quimicamente, ademais são dotados de degradação específica. A modificação química representa uma alternativa ao inconveniente causado pela elevada hidrossolubilidade destes produtos, a qual poderá ocasionar liberação prematura do fármaco. No presente estudo, a goma guar foi fosfatada com trimetafosfato trisódico, sendo em seguida associada a etilcelulose, visando a formação de filmes isolados. Os produtos resultantes foram caracterizados físico-quimicamente (IV TF e DSC), sendo também avaliada a transmissão de vapor de água (TVA) e o grau de intumescimento (Ii%). Os resultados mostraram a fosfatação da goma guar, além da redução do intumescimento e permeabilidade após reticulação. Estes resultados caracterizam maior potencial de aplicação da goma guar fosfatada para sistemas reservatórios orais em relação a goma natural.The uses of polysaccharides are attracting a lot of attention for development of new specific drug delivery systems. These polymers are found in abundance, are inexpensive, are available in a variety of structure with varied properties and can be easily modified chemically; in addition, they are specific biodegradable. The cross linking of polysaccharides is an alternative for the inconvenience brought by it?s high water solubility, which can lead to early drug delivery. In the present study, guar gum was phosphated with trisodium trimetaphosphate and, than, associated with ethylcellulose on the purpose of forming isolated films. The resulting products were physicochemical characterized (with FT IR and DSC), the water vapour transmission (WVT) and the swelling index (Ii%) were also evaluated. The results confirmed the guar gum phosphatation and showed swelling and water permeability reduction due to the cross linking. Phosphated guar gum has therefore a greater application potential in oral drug delivery systems than native guar gum.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Phosphated guar gum: potential ingredient in the development of ethylcellulose isolated films

O uso de polissacarídeos tem atraído grande atenção no desenvolvimento de novos sistemas para liberação específica de fármacos. Esses polímeros estão disponíveis em abundância, a baixo custo, apresentando uma variedade de estruturas e propriedades, podendo ser facilmente modificados quimicamente, ademais são dotados de degradação específica. A modificação química representa uma alternativa ao inconveniente causado pela elevada hidrossolubilidade destes produtos, a qual poderá ocasionar liberação prematura do fármaco. No presente estudo, a goma guar foi fosfatada com trimetafosfato trisódico, sendo em seguida associada a etilcelulose, visando a formação de filmes isolados. Os produtos resultantes foram caracterizados físico-quimicamente (IV TF e DSC), sendo também avaliada a transmissão de vapor de água (TVA) e o grau de intumescimento (Ii%). Os resultados mostraram a fosfatação da goma guar, além da redução do intumescimento e permeabilidade após reticulação. Estes resultados caracterizam maior potencial de aplicação da goma guar fosfatada para sistemas reservatórios orais em relação a goma natural.The uses of polysaccharides are attracting a lot of attention for development of new specific drug delivery systems. These polymers are found in abundance, are inexpensive, are available in a variety of structure with varied properties and can be easily modified chemically; in addition, they are specific biodegradable. The cross linking of polysaccharides is an alternative for the inconvenience brought by it?s high water solubility, which can lead to early drug delivery. In the present study, guar gum was phosphated with trisodium trimetaphosphate and, than, associated with ethylcellulose on the purpose of forming isolated films. The resulting products were physicochemical characterized (with FT IR and DSC), the water vapour transmission (WVT) and the swelling index (Ii%) were also evaluated. The results confirmed the guar gum phosphatation and showed swelling and water permeability reduction due to the cross linking. Phosphated guar gum has therefore a greater application potential in oral drug delivery systems than native guar gum.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Synthesis and characterization of phosphated crosslinked chondroitin sulfate: potential ingredient for specific drug delivery

Debido a su biodegradabilidad varios polímeros naturales, tales como los polisacáridos, han sido propuestos como excipientes adecuados para desarrollar sistemas de liberación controlada para la administración oral. El sulfato de condroitina (ChS), un mucopolisácarido altamente soluble en agua, fue reticulado con trimetafosfato de sodio (TMFS) para conseguir una reducción de su hidrosolubilidad. ChS fue tratado com TMFS en tres diferentes proporciones, en dispersión acuosa a pH 12 por 2 h a temperatura ambiente y en seguida secado. Los productos obtenidos fueron analizados por FTIR y DSC y comparados con los correspondientes análisis de ChS. Los resultados mostraron que (a) el TMFS efectivamente retícula al ChS y (b) los productos reticulados presentan una disminución de la absorción de agua, comparado con el polisacárido natural ChS. Estos resultados permiten concluir que el ChS modificado presenta buenas perspectivas para su uso en formulaciones farmacéuticas de liberación modificada.Because of its biodegradability several natural polymers, such as polysaccharides, have been proposed as appropriate excipients for the development of controlled drug delivery systems for oral administration. Chondroitin sulfate (ChS), a highly water-soluble mucopolysaccharide, was crosslinked with trisodium trimetaphosphate (TMFS) in order to achieve a reduction of its hydro-solubility. ChS was treated with TMFS in three different proportions, in aqueous dispersion at pH 12 for 2 h at room temperature, and then dried. The products obtained were analysed by their Fourier-transformed infrared (FTIR) spectra and differential scanning calorimetry (DSC) curves, which were compared with the analyses of a natural ChS control sample. The results showed that (a) TMFS has effective crosslinking action over ChS and (b) the crosslinked products have reduced water affinity, compared to the natural polysaccharide. These results lead to the conclusion that modified ChS presents good perspectives for its use on modified release pharmaceutical formulations.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Synthesis and characterization of phosphated crosslinked chondroitin sulfate: potential ingredient for specific drug delivery

Debido a su biodegradabilidad varios polímeros naturales, tales como los polisacáridos, han sido propuestos como excipientes adecuados para desarrollar sistemas de liberación controlada para la administración oral. El sulfato de condroitina (ChS), un mucopolisácarido altamente soluble en agua, fue reticulado con trimetafosfato de sodio (TMFS) para conseguir una reducción de su hidrosolubilidad. ChS fue tratado com TMFS en tres diferentes proporciones, en dispersión acuosa a pH 12 por 2 h a temperatura ambiente y en seguida secado. Los productos obtenidos fueron analizados por FTIR y DSC y comparados con los correspondientes análisis de ChS. Los resultados mostraron que (a) el TMFS efectivamente retícula al ChS y (b) los productos reticulados presentan una disminución de la absorción de agua, comparado con el polisacárido natural ChS. Estos resultados permiten concluir que el ChS modificado presenta buenas perspectivas para su uso en formulaciones farmacéuticas de liberación modificada.Because of its biodegradability several natural polymers, such as polysaccharides, have been proposed as appropriate excipients for the development of controlled drug delivery systems for oral administration. Chondroitin sulfate (ChS), a highly water-soluble mucopolysaccharide, was crosslinked with trisodium trimetaphosphate (TMFS) in order to achieve a reduction of its hydro-solubility. ChS was treated with TMFS in three different proportions, in aqueous dispersion at pH 12 for 2 h at room temperature, and then dried. The products obtained were analysed by their Fourier-transformed infrared (FTIR) spectra and differential scanning calorimetry (DSC) curves, which were compared with the analyses of a natural ChS control sample. The results showed that (a) TMFS has effective crosslinking action over ChS and (b) the crosslinked products have reduced water affinity, compared to the natural polysaccharide. These results lead to the conclusion that modified ChS presents good perspectives for its use on modified release pharmaceutical formulations.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Caracterización de películas de etilcelulosa conteniendo polisacáridos naturales por análisis térmico y espectroscopía FTIR

a etilcelulosa (EC) ha sido ampliamente usada como material adecuado en el desarrollo de nuevos sistemas para liberación modificada de fármacos. Algunos oligo-polisacáridos como inulina (IN), goma guar(GG) y sus derivados han sido propuestos como materiales biodegradables para liberación específica de sitio. El objetivo de este estudio fue caracterizar películas aisladas de EC asociadaa a alguno de los siguientes oligo-polisacáridos: IN, GG y levana (LEV). Las técnicas usadas fueron: análisis térmico (TG y DSC) y espectroscopía de infrarojo com transformada de Fourier (FTIR). Para obtener las películas, un volumen determinado de cada dispersión acuosa (EC/IN, EC/GG, EC/LEV) fue colocado en placa de teflon y luego evaporado el solvente. Los espectros FTIR sugieren la existencia de interacciones de cadenas poliméricas en los sistemas EC/IN y EC/LEV por dislocamientos de la banda debida a la vibración de O-H. En las curvas de TG y DSC también fueron observadas algunas variaciones. La temperatura en la cual la velocidad de la primera etapa de degradación térmica pasa por un máximo (Tmax1) y la frequencia en la cual la banda de O-H está centrada ((OH) presentaron un comportamiento semejante en los sistemas estudiados.Ethylcellulose (EC) has been widely used as a coating material for controlled release systems. Some oligo-polysaccharides such as inulin (IN), guar gum (GG) and their derivatives have been proposed as biodegradable materials for site-specific releases. The objective of this study was to characterise free films composed of EC associated to IN or GG or levan (LEV) using thermal analysis and FTIR spectroscopy. Polymer dispersions of EC/IN, EC/GG or EC/LEV, containing up 30% of the oligo-polysaccharide, were used for film casting on a Teflon? plate. The FTIR spectra obtained suggest hydrogen bond interactions of EC/IN and EC/LEV polymeric chains. The thermal analysis (TGA and DSC) of the blends showed temperature dislocations of some parameters. It was observed that Tmax1 (temperature at which a thermal degradation rate goes up to a maximum) and (OH (wavenumber at which the OH absorption band are centralised) show similar trends in the composition range of the studied blends.Colegio de Farmacéuticos de la Provincia de Buenos Aire