Impact of the degradation leachate of the polyacrylonitrile-based material UP2W on the retention of Ni(II), Eu(III) and Pu(IV) by cement

The uptake of $^{63}$Ni(II), $^{152}$Eu(III) and $^{242}$Pu(IV) by hardened cement paste (HCP, CEM I) in the degradation stage II (pH ≈ 12.5, [Ca] ≈ 0.02 M) was investigated in the presence of a degradation leachate of UP2W, a polyacrylonitrile-based (PAN) material used as a filter aid in nuclear power plants. The degradation leachate with a concentration of dissolved organic carbon of ∼40 ppm was obtained from the degradation of UP2W in portlandite-buffered solutions for ca. 1100 days. Redox conditions in the Pu systems were buffered with hydroquinone, which defines mildly reducing conditions (pe + pH ≈ 10) where Pu(IV) is the predominant oxidation state. The degradation leachate investigated in this work is moderately sorbed by cement, with distribution ratios (R$_d$) of (0.35 ± 0.15) m$^3$ kg$^{−1}$. These values are 30 to 100 times greater than distribution ratios previously reported for proxy ligands of PAN degradation products, i.e., glutaric acid, α-hydroxyisobutyric acid and 3-hydroxybutyric acid. The presence of the degradation leachate induces a moderate decrease in the uptake of $^{63}$Ni(II), $^{152}$Eu(III) and $^{242}$Pu(IV) by cement, as compared to the sorption in the presence of the proxy ligands. Nevertheless, retention in the presence of the degradation leachate remains high for all investigated radionuclides, with Rd($^{63}$Ni(II)) ≈ 2 m$^3$ kg$^{−1}$, Rd($^{152}$Eu(III)) ≈ 100 m$^3$ kg$^{−1}$ and Rd($^{242}$Pu(IV)) ≈ 30 m$^3$ kg$^{−1}$. These observations possibly reflect that the multiple functionalities (–COOH, –OH, amide groups) expected in the macromolecules (10–15 kDa) present in the degradation leachate, can offer further binding/chelating capabilities compared to the small organic proxy ligands with at most bidentate binding

Solubility of Ca( ii ), Ni( ii ), Nd( iii ) and Pu( iv ) in the presence of proxy ligands for the degradation of polyacrylonitrile in cementitious systems

The solubility of Ca(OH)$_{2}$(cr), β-Ni(OH)$_{2}$(cr), Nd(OH)$_{3}$(s) and PuO$_{2}$(ncr, hyd) was investigated in cement porewater solutions containing glutarate (GTA), α-hydroxyisobutarate (HIBA) and 3-hydroxybutarate (HBA). These ligands were proposed as probable degradation products of UP2W, a polyacrylonitrile-based filter aid used in nuclear power plants. Results obtained in this work are compared with reported solubility data in the presence of iso-saccharinic acid (ISA), a polyhydroxocarboxylic acid resulting from cellulose degradation. None of the investigated proxy ligands shows any significant impact on the solubility of Ca(II), Nd(III) or Pu(IV) in cement porewater solutions. Although the formation of binary complexes M–L (M = Ca(II), Nd(III), An(IV); L = GTA, HIBA, HBA) under acidic conditions is described in the literature, these organic ligands cannot outcompete hydrolysis under hyperalkaline conditions. GTA, HIBA and HBA induce a slight increase in the solubility of β-Ni(OH)$_{2}$(cr) at [L]$_{tot}$ = 0.1 M. This observation supports the formation of stable Ni(II)–GTA, –HIBA and –HBA complexes in hyperalkaline conditions, although the exact stoichiometry of these complexes remains unknown. The comparison of these results with solubility data in the presence of ISA confirms the stronger complexation properties of the latter ligand. Even though HIBA and HBA are carboxylic acids containing one alcohol group, this comparison shows that additional alcohol groups are required to efficiently chelate the metal ion and outcompete hydrolysis. This conclusion is supported by DFT calculations on the Pu(IV)-OH–L systems (L = GTA, HIBA and HBA), which indicate that the complexation with the proxy ligands takes places through the carboxylate group. XRD of selected solid phases after equilibration with proxy ligands at [L]$_{tot}$ = 0.1 M confirms that Ca(II), Ni(II), Nd(III) and Pu(IV) starting solid materials remained mostly unaltered in the course of the experiments. However, the presence of new XRD features suggests the possible formation of secondary phases. These results allow assessment of the effect of the proposed proxy ligands on the solubility of key radionuclides and metal ions in cementitious systems relevant for low and intermediate level waste, and feed into on-going sorption studies evaluating the impact of UP2W degradation products on the uptake of radionuclides by cement

A dynamic and multifunctional account of middle‐range theories

This article develops a novel account of middle‐range theories for combining theoretical and empirical analysis in explanatory sociology. I first revisit Robert K. Merton’s original ideas on middle‐range theories and identify a tension between his developmental approach to middle‐range theorizing that recognizes multiple functions of theories in sociological research and his static definition of the concept of middle‐range theory that focuses only on empirical testing of theories. Drawing on Merton's ideas on theorizing and recent discussions on mechanism‐based explanations, I argue that this tension can be resolved by decomposing a middle‐range theory into three interrelated and evolving components that perform different functions in sociological research: (i) a conceptual framework about social phenomena that is a set of interrelated concepts that evolve in close connection with empirical analysis; (ii) a mechanism schema that is an abstract and incomplete description of a social mechanism; and (iii) a cluster of all mechanism‐based explanations of social phenomena that are based on the particular mechanism schema. I show how these components develop over time and how they serve different functions in sociological theorizing and research. Finally, I illustrate these ideas by discussing Merton’s theory of the Matthew effect in science and its more recent applications in sociology.This article develops a novel account of middle‐range theories for combining theoretical and empirical analysis in explanatory sociology. I first revisit Robert K. Merton’s original ideas on middle‐range theories and identify a tension between his developmental approach to middle‐range theorizing that recognizes multiple functions of theories in sociological research and his static definition of the concept of middle‐range theory that focuses only on empirical testing of theories. Drawing on Merton's ideas on theorizing and recent discussions on mechanism‐based explanations, I argue that this tension can be resolved by decomposing a middle‐range theory into three interrelated and evolving components that perform different functions in sociological research: (i) a conceptual framework about social phenomena that is a set of interrelated concepts that evolve in close connection with empirical analysis; (ii) a mechanism schema that is an abstract and incomplete description of a social mechanism; and (iii) a cluster of all mechanism‐based explanations of social phenomena that are based on the particular mechanism schema. I show how these components develop over time and how they serve different functions in sociological theorizing and research. Finally, I illustrate these ideas by discussing Merton’s theory of the Matthew effect in science and its more recent applications in sociology.Peer reviewe

Mortalidade entre Idosos no Estado do Paraná e no município de Foz do Iguaçu

Trabalho de Conclusão da Residência apresentado ao Programa de Residência Multiprofissional em Saúde da Família da Universidade Federal da Integração Latino- Americana, como requisito parcial para obtenção do título de Especialista em Saúde da Família na modalidade de residência. Orientador: Walfrido Svoboda. (Prof. Dr. do Curso de Saúde Coletiva - UNILA) e Coorientadora: Carmen Justina Gamarra. (Profa. Dra. do Curso de Saúde Coletiva - UNILA)Objetivo: Analisar a tendência da mortalidade entre idosos residentes no estado do Paraná e no município de Foz do Iguaçu, no período de 2001 a 2012, e mortalidade proporcional por capítulos CID-10. Método: Trata-se de um estudo descritivo, ecológico de série temporal. Os dados dos óbitos e da população idosa de 60 anos ou mais foram obtidos por meio do Sistema de Informação de mortalidade SIM/DATASUS. Foram calculadas as taxas anuais de mortalidade bruta e padronizadas por sexo e faixa etária. Para os dados de mortalidade proporcional por capítulos CID-10 foram calculados os percentuais para os anos selecionados de 2001; 2006; 2011; 2016. As informações foram tabuladas em planilhas do Excel, sendo construídas tabelas e gráficos e analisados por meio de regressão linear simples. Resultados: Observou-se tendência declinante da mortalidade dos idosos no estado do Paraná e no município de Foz do Iguaçu. Ao longo do estudo verificou-se que as doenças do aparelho circulatório constituem-se como a primeira e principal causa de óbito, seguido das neoplasias e doenças do aparelho respiratório. Conclusão: No período analisado, a tendência da mortalidade padronizadas dos idosos obteve decréscimo tanto no Estado como no município, sendo observados maiores coeficientes de mortalidade entre os homens quando comparado às mulheres.Objective: To analyze the mortality trend among elderly people living in the state of Para- ná and in the municipality of Foz do Iguaçu, from 2001 to 2012, and proportional mortality by ICD-10 chapters. Method: This is a descriptive, ecological time series study. Data on deaths and the elderly population aged 60 years and over were obtained using the SIM / Datasus Mortality Infor- mation System. Gross annual mortality rates were standardized and standardized by gen- der and age group. The information was tabulated in Excel spreadsheets, and tables and graphs were constructed and analyzed using simple linear regression. Results: In general terms, a declining trend in mortality among the elderly was observed in the state of Paraná and in the city of Foz do Iguaçu. Throughout the study it was verified that diseases of the circulatory system constitute the first and main cause of death, fol- lowed by neoplasias and diseases of the respiratory system. Conclusion: In the period analyzed, the general trend of standardized mortality among the elderly decreased both in the state and in the municipality, with higher mortality rates among men when compared to womenObjetivo: Analizar la tendencia de la mortalidad entre ancianos residentes en el estado de Paraná y en el municipio de Foz do Iguaçu, en el período de 2001 a 2012, y mortali- dad proporcional por capítulos CID-10. Método: Se trata de un estudio descriptivo, eco- lógico de serie temporal. Los datos de mortalidad y de la población de la tercera edad (mayor de 60años) fueron obtenidos por medio del sistema de información de mortalidad SIM/DATASUS. Fueron calculadas las tasas anuales de mortalidad bruta y estandariza- das por sexo y edad. Las informaciones fueron tabuladas en planillas de cálculo Micro- soft Excel, siendo construidas tablas, gráficos e analizados por medio de regresión linear simple. Resultados: En términos generales fue observada la tendencia declinante de la mortali- dad en personas de la tercera edad en el Estado de Paraná y en el Municipio de Foz de Iguazú. A lo largo de este estudio, se verifico que las enfermedades del aparato circula- torio se consideran como la primera causa de muerte, seguido por Cáncer e enfermeda- des del Aparato Respiratorio. Conclusión: En el periodo analizado, la tendencia de la mortalidad estandarizada en personas de la tercera edad obtuvo decrecimos tanto en el Estado de Paraná como en el Municipio, siendo observados mayores coeficientes de mortalidad en hombres compara- do con mujere

Cardiopulmonary involvement in Puumala hantavirus infection

Abstract Background: Hantavirus infections cause potentially life-threatening disease in humans world-wide. Infections with American hantaviruses may lead to hantavirus pulmonary syndrome characterised by severe cardiopulmonary distress with high mortality. Pulmonary involvement in European Puumala hantavirus (PUUV) infection has been reported, whereas knowledge of potential cardiac manifestations is limited. We aimed to comprehensively investigate cardiopulmonary involvement in patients with PUUV-infection