Parental and trophic transfer of nanoscale plastic debris in an assembled aquatic food chain as a function of particle size

Environmental Biolog

Method for Extraction and Quantification of Metal-Based Nanoparticles in Biological Media: Number-Based Biodistribution and Bioconcentration

A multistep sample preparation method was developed to separate metal-based engineered nanoparticles (ENPs) from biological samples. The method was developed using spiked zebrafish tissues and standard titanium dioxide (TiO2) and cerium dioxide (CeO2) ENPs. Single-particle inductively coupled plasma mass spectrometry was used to quantify the separated particles in terms of number concentration. This method demonstrated mass recoveries of more than 90% and did not strikingly alter the median particles size. High number recoveries were calculated for CeO2 ENPs (>84%). Particle number recoveries were poor for TiO2 ENPs (48Ca with the measured isotope 48Ti. The method was verified using zebrafish exposed to CeO2 ENPs to test its applicability for nanotoxicokinetic investigations. Total mass of Ce and particle number concentration of CeO2 ENPs were measured in different tissues. Notably, the mass-based biodistribution of Ce in the tissues did not follow the number-based biodistribution of CeO2. Moreover, the calculated mass-based bioconcentration factors showed a different pattern in comparison to the number-based bioconcentration factors. Our findings suggest that considering mass as the sole dose-metric may not provide sufficient information to investigate toxicity and toxicokinetics of ENPs.Environmental Biolog

El nuevo modelo del sistema de salud: inicios, rutas y dificultades

Como puntal del sistema público de protección social, el nuevo modelo del sistema de salud se instala en el país muy tardíamente en relación a sociedades de la región que iniciaron este proceso décadas atrás. En esas sociedades los momentos fundacionales del sistema de salud con la asunción de los riesgos de las trabajadoras y los trabajadores y de la población contó con la vigorosa iniciativa estatal. Contrariamente en el país, el nuevo sistema de salud inicia sus fundamentos con el amplio involucramiento de la iniciativa privada en la administración de las cotizaciones y rendición del servicio y, por el contrario, con una disminución de la preeminencia estatal, cuyo papel central es relegado al rol regulador. La Fundación Friedrich Ebert (FES) y el Centro Universitario de Estudios Políticos y Sociales (CUEPS) de la Pontificia Universidad Católica Madre y Maestra, en el marco de los Foros sobre Políticas Sociales y Bienestar, ponen a la disposición del público estos trabajos sobre el nuevo sistema de salud en el interés de sustentar un debate y alertar de manera documentada elementos vulnerables y retos del nuevo modelo.Índice: Presentación 11. I. Hacia un nuevo Sistema Nacional de Salud. ¿Por qué es necesaria una reforma del sector salud? / Pedro Luis Castellanos 13. II. El Seguro Familiar de Salud en República Dominicana: una reforma impostergable / Luis Morales 55. Comentario / Rosa María Suárez 133. III. Nuevo rol de los establecimientos de salud: reflexiones sobre las redes de servicios públicos de salud / Rosa María Suárez 141. IV. Financiación pública del sector salud y la seguridad social en salud en la República Dominicana: antes y después de la reforma / Jefrey Lizardo 197. Comentario / Gustavo Rojas Lara 231. Relatoria / Alejandro Moliné 237. V. La viabilidad del Régimen Contributivo-Subsidiado en el Seguro Familiar de Salud / Chanel Rosa Chupani 261. VI. Garantía y protección de los derechos de los afiliados en el Sistema Dominicano de Seguridad Social (SDSS) / Bernardo Matías 281. Comentario / Nélsida Marmolejos 301. Relatoria / Alejandro Moliné 309

Engineered nanoselenium supplemented fish diet: toxicity comparison with ionic selenium and stability against particle dissolution, aggregation and release

Transformation of nutrients to their nano-form, such as selenium (Se) engineered nanonutrients (Se-ENNs), is expected to enhance the absorption of the nutrients into fish and increase the efficiency of the feed. However, dissolution, aggregation, and release of ENNs from the feed matrix may decrease the efficiency of the Se-ENNs. In this study, we provided fish feed supplemented with Se-ENNs which do not aggregate or dissolve and the particles are also not released from the feed matrix. As a proof of principle, we compared the toxicity of a diet containing Se-ENNs of two different sizes (60 nm and 120 nm) with diets containing ionic Se. The adverse effects were measured by monitoring the survival rate, acetylcholinesterase (AChE) levels and swimming behavior of zebrafish over 21 days of feeding with either the Se-ENNs or ionic Se supplemented fish diets. The number size distribution of the 60 nm Se-ENNs in the diet was similar to that in MilliQ water, while the size distribution of the 120 nm Se-ENNs in the diet was slightly wider. Ion and particle release from Se-ENNs containing diets in the exposure media was not observed, indicating the stability of the particles in the feed matrices. To determine toxicity, zebrafish (Danio rerio) were nourished using a control diet (without Se and Se-ENNs), Se (sodium selenite) containing diets (with 2.4 or 240 mg Se per kg feed) and Se-ENNs containing diets (with 2.4 or 240 mg Se-ENNs of 60 or 120 nm per kg feed) for 21 days. Both sizes of Se-ENNs were taken up in the fish, however only the 120 nm Se-ENNs were detected in the brains of fish. Zebrafish fed with Se-ENNs supplemented diets (60 and 120 nm) showed normal swimming behavior compared to the control. No significant alteration was determined in the AChE activity of the fish fed with the Se-ENNs supplemented diet. In contrast, feeding the zebrafish with a diet containing 240 mg kg−1 Se led to lethal effects. These observations clearly depict the potential benefits of using Se-ENNs as nutrients in fish feed.Environmental Biolog