Activation of persulfate by LaFe1-xCoxO3 perovskite catalysts for the degradation of phenolics: Effect of synthetic method and metal substitution.

The presence of resistant organic pollutants in environmental substrates requires the development and finding of novel decontamination methods. Advanced oxidation processes are among the most effective methods used for degradation of these pollutants through their oxidation and degradation into non-toxic and harmless, for the environment, final products. Ιn this research, a series of perovskites of ABO3-type, with La and Fe and/or Co in A and B positions respectively, LaFe1-xCoxO3 (x = 0, 0.25, 0.5, 0.75, 1), were synthesized with two different methods, a soft template method using anionic surfactant and by glycine combustion method and studied for their catalytic activity towards the degradation of phenolic compounds, a major class of environmental pollutants, through persulfate activation. The catalytic activity depended both by the B metal ion of perovskites and their ratio as well as by the synthesis method. LaCoO3 prepared with the anionic surfactant method, showed the highest catalytic activity with a rate constant of 0.024 min-1. Furthermore, the synthesis method also influenced the stability of perovskites as metal leaching studies showed that perovskites synthesized with the anionic surfactant showed greater stability. Quenching experiments were also used in order to shed light on the catalytic activation mechanism of persulfate for the degradation of phenolics. Overall, the results showed that the synthesis method can significantly affect the catalytic activity of the materials and their stability since the same materials synthesized with different methods show significantly different catalytic properties.

Molecular and clinical aspects of embryotoxicity induced by acetylcholinesterase inhibitors.

Acetylcholinesterase inhibitors are widely used for a variety of medical, agricultural and public health purposes. Consequently, exposure is highly possible during lifetime. However, their systematic use raises concerns for the potential impact on the fetus and newborn since these substances may affect angiogenesis, the neonatal and maternal intensive care, neuroimmune function and response, mammary growth/lactation via cholinergic/non-cholinergic central and peripheral neuroendocrine pathways. New methodologies, neuroscientific technologies and research studies are needed to harness existing knowledge along with the proper management, availability for new acetylcholinesterase inhibitors, with stable pharmacodynamics and clinical outcomes.

Gastrointestinal stromal tumors during pregnancy: a systematic review of an uncommon but treatable malignancy

Although modern social structure and medical advances have led to the increasing number of women childbearing in older age, cancer remains a rare diagnosis during pregnancy. There is little given information throughout the literature concerning gestation associated with the coexistence of gastrointestinal stromal tumor (GIST). In this review, we present 12 reported cases of GIST during pregnancy and we discuss the maternal and fetal outcome, as well as the therapeutic plan that was followed in each situation. From the collected data, 8 out of 12 cases had an uneventful outcome of their fetus. In 11 out of 12 cases surgical excision of the tumor was the treatment of choice, while seven women were treated with imatinib. Two of them were already on imatinib therapy during conception due to preexisting GIST diagnosis. Surgery remains the gold standard for the treatment of local or resectable GIST, while published data concerning the use of imatinib during pregnancy indicate that teratogenicity or fetal loss might be induced, especially if given during the first trimester of pregnancy. GIST during gestational period is a rare tumor in which a multidisciplinary approach should be designed, taking always into consideration that it has a favorable outcome on targeted treatment (AU)

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Gastrointestinal stromal tumors during pregnancy: a systematic review of an uncommon but treatable malignancy.

Although modern social structure and medical advances have led to the increasing number of women childbearing in older age, cancer remains a rare diagnosis during pregnancy. There is little given information throughout the literature concerning gestation associated with the coexistence of gastrointestinal stromal tumor (GIST). In this review, we present 12 reported cases of GIST during pregnancy and we discuss the maternal and fetal outcome, as well as the therapeutic plan that was followed in each situation. From the collected data, 8 out of 12 cases had an uneventful outcome of their fetus. In 11 out of 12 cases surgical excision of the tumor was the treatment of choice, while seven women were treated with imatinib. Two of them were already on imatinib therapy during conception due to preexisting GIST diagnosis. Surgery remains the gold standard for the treatment of local or resectable GIST, while published data concerning the use of imatinib during pregnancy indicate that teratogenicity or fetal loss might be induced, especially if given during the first trimester of pregnancy. GIST during gestational period is a rare tumor in which a multidisciplinary approach should be designed, taking always into consideration that it has a favorable outcome on targeted treatment.

Estimation of diffusion parameters in functionalized silicas with modulated porosity. Part I: chromatographic studies.

The diffusion parameters of binary gas mixture He (tracer gas)-N2 (carrier gas) in hybrid organic-inorganic SiO2-X porous solids which have suffered gradual functionalization with functional groups X of increasing length (X = psi, [triple bond]Si-H, [triple bond]Si-CH2OH, [triple bond]Si-(CH2)3OH, [triple bond]Si-(CH2)11CH3) are reported. The effective diffusivities Deff, the Henry law constants K as well as the tortuosity factors tau for the examined solids were estimated by a typical pulse gas chromatographic method. Analysis of the experimental results was carried out by the well-known method of linearization of moments. The moments s analysis provides a powerful means for extracting diffusion parameters from the experimental response curves The proposed methodology is simple compared to other similar studies and provides rapidly reliable data. The results of this work indicate that the effective diffusivity Deff in porous networks drops markedly as the initial porosity of the parent SiO2 sample is blocked by the functionalization of the pore surfaces with functional groups of increasing size, [triple bond]Si-H, [triple bond]Si-CH2OH, [triple bond]Si-(CH2)3OH and [triple bond]Si-(CH2)11CH3. The low values of the Henry law constants K found indicate that the adsorption of He on the porous surfaces for all the solids is weak. Also, the tortuosity factor r is proportionally correlated to the pore blocking effects and the percolation phenomena of gases flowing into the porous network.

Estimation of diffusion parameters in functionalized silicas with modulated porosity. Part II: pore network modeling.

In this work, the pore structure of those five (5) silicas SiO2-X (see Part I) which have suffered gradual functionalization with functional groups X of increasing length (X = psi, [triple bond]Si-H, [triple bond]Si-CH2OH, [triple bond]Si-(CH2)3OH, [triple bond]Si-(CH2)11CH3), is modeled as a three-dimensional cubic network of cylindrical pores. Those hybrids organic-inorganic SiO2-X samples are characterized by different extent of pore blocking effects. The pores of samples are represented in a 9 x 9 x 9 lattice by the nodes as well the bonds that are interconnected in a so-called dual site-bond model, DSBM, network. The pore network is developed using a Monte Carlo statistical method where the cylindrical pores (nodes and bonds) are randomly assigned into the lattice, until matching of the theoretical results to the experimental data of N2 adsorption-desorption measurements. Thus, a visual picture of the porous solid is possible. This realistic network is used next in order to study the steady-state gas transport (Knudsen gas-phase and viscous diffusion) properties for the examined materials and how flow processes depend on the morphology of the pore structure. The pore diffusivity Dp and total permeability P of each porous medium is determined based on theoretical calculations and the structural statistical parameters, such as porosity epsilonp, tortuosity factor tau and connectivity c of pores is discussed with the corresponding experimental data described in Part I of this work. The results indicate clearly that the diffusion model made it possible to predict pore effective diffusivity in these porous media in very good agreement with the corresponding experimental results for all the examined solids (Part I). The pore diffusivity increases significantly as the value of the pore connectivity increases but the transport properties of the network are influenced strongly at lowest connectivity. Also the predicted tortuosity factor is related inversely to the extent of interconnection of pores in these solids, which indicates that the influence of pore branching to the tortuosity factor of the pore network decreases, as connectivity increases.