Impact of gonadectomy on blood pressure regulation in ageing male and female rats

Sexual dimorphism in blood pressure has been associated with differential expression of the angiotensin II (AII) receptors and with activity of the nervous system. It is generally accepted that aging affects kidney function as well as autonomic nervous system and hormonal balance. Given that hypertension is more prevalent in men than women until women reach their seventh decade we hypothesised that females would be relatively protected from adverse effects of ageing compared to males, and that this would be mediated by the protective effect of ovarian steroids. Intact and gonadectomised male and female normotensive Wistar rats aged 6, 12 and 18 months were used to study renal function, blood pressure, heart rate and blood pressure variability. We observed that intact females had lower levels of proteinuria and higher (12.5%) creatinine clearance compared to intact males, and that this difference was abolished by castration but not by ovariectomy. Ovariectomy resulted in a change by 9% in heart rate, resulting in similar cardiovascular parameters to those observed in males or gonadectomised males. Spectral analysis of systolic blood pressure revealed that high frequency power spectra were significantly elevated in the females vs. males and were reduced by ovariectomy. Taken altogether the results show that females are protected from age-related declining renal function and to a lesser extent from rising blood pressure in comparison to males. Whilst ovariectomy had some deleterious effects in females, the strongest effects were associated with gonadectomy in males, suggesting a damaging effect of male hormones

Transformations through pseudomorphosis of asbestos minerals in thermally processed asbestos-containing materials investigated through SEM/EDS and micro-Raman spectroscopy: implications for recycling of hazardous wastes

Asbestos-containing materials, extensively used in the past in many European countries, are now considered hazardous wastes of great concern. It has been proved that inertization can be obtained via thermal treatment above 1100 °C. This solution relies upon the scientific evidence that all asbestos minerals at high temperature transform into stable crystalline silicates via a solid state recrystallization process [1]. Asbestos fibres preserve the same external crystal habit although a complete modification of the structure at a molecular scale occurred. This phenomenon is called pseudomorphosis. With increasing the temperature of the thermal treatment above 650-750 °C, the transformation sequence of chrysotile asbestos predicts the crystallization of forsterite (Mg2SiO4) and enstatite (MgSiO3 ) [1]. In a system high in Ca, such as cement-asbestos, crystallization of cement phases such as larnite (Ca2SiO4), ferrite (ideally Ca4Al2Fe2O10), and Al-,Ca-,Mg-rich silicates, such as akermanite (ideally Ca2MgSi2O7) and merwinite (ideally Ca3MgSi2O8), occurs. In this work, analytical and spectroscopic techniques coupled with microscopy allowed for the study of individual residual pseudo-morphosed fibre bundles, in cement-asbestos samples heat treated at 1200 °C. Phases detected were mainly monticellite (CaMgSiO4) or akermanite. They likely formed through the reactions: CaO + MgSiO3 (en) -> CaMgSiO4 (mtc), and CaMgSiO4 (mtc) + CaO + SiO2 -> Ca2MgSiO7 (ake). This suggests that, although transformation reactions occurred largely at the solid state, a substantial mobilisation of Ca and Mg resulted. Such a process is essential for the attainment of the bulk mineralogical composition predicted by the phase diagrams in the system CaO-MgO-SiO2 [2]; however, because of crystallization under non equilibrium conditions, departures from the expected bulk phase composition are still observed. This study contributes to the definition of factors conditioning the recycling of transformed cement-asbestos as secondary raw material [2-3]

The effect of firing temperature on the composition and microstructure of a geocement-based binder of sodium water-glass

The fire performance of a geocement-based binder was investigated with a combination of analytical techniques, in terms of changes in composition and microstructure. Geocement, formulated as Na2O∙Al2O3∙6SiO2∙20H2O, was prepared using metakaolin, sodium water-glass, rotten stone and sodium hydroxide. The mixture was homogenized by passing through a hydrodynamic cavitator. Cubes of 20 mm were prepared, hardened at laboratory conditions for 28 days, and subsequently burnt at 600, 800 and 1200 °C in a laboratory furnace. Cavitation treatment resulted in a highly amorphous binder; amorphous fraction decreased upon firing up to 800 °C due to crystallization, and increased above 1000 °C because of melt formation. Porosity increased with firing temperature and pores larger than 1 mm in diameter prevailed at 1200 °C. The material remained stable up to 1200 °C. The results indicate the adequacy of this geocement-based binder for preparing fire-protecting materials

Long-term thaumasite sulfate attack on Portland-limestone cement concrete: A multi-technique analytical approach for assessing phase assemblage

Multiple techniques were applied to the investigation of the phase composition of the deteriorated surface of Portland-limestone cement concrete specimens exposed for 10 years to conditions promoting thaumasite sulfate attack. The results were interpreted in terms of the limestone content of cement and the incorporation of supplementary cementitious materials (SCMs) (natural pozzolana, blastfurnace slag, metakaolin). Thaumasite, detected in high amounts in concrete specimens made without SCMs, was associated with Al to some extent. Considerable degradation of calcium silicate hydrate occurred in all specimens, resulting in the formation of Al-associated cross-linked silicate chains, magnesium silicate hydrate and silica gel, a process most effectively prevented by metakaolin. For the highest limestone content in cement or use of natural pozzolana, thaumasite underwent extensive decomposition. Al incorporation into cross-linked silicate chains increased with increasing limestone content in cement. Longer aluminosilicate chains with larger Al fractions were observed in concrete specimens incorporating SCMs

A solid state NMR and in-situ infrared spectroscopy study on the setting reaction of magnesium sodium phosphate cement

In the present work, the setting reaction of magnesium sodium phosphate cement was followed in time with in-situ attenuated total reflectance Fourier-transform infrared spectroscopy and solid state nuclear magnetic resonance spectroscopy, in order to gain insights into the products and phase transformations. The results indicated that, during the progress of the reaction, amorphous phases containing the H2PO4− structural group converted into phases containing HPO42− and finally PO43−. The increase in pH triggered by the MgO dissolution was considered as the driving force for the transformations. This is supposed to promote the establishment of a high degree of supersaturation close to the surface of MgO grains, resulting in kinetically driven transformations and favouring the amorphous nature of the products. It is suggested that in the later stages of the reaction, two orthophosphate amorphous phases, hosting bound water molecules, coexisted, with the one showing a relatively more ordered 31P local environment, converting into a second with a more disordered phosphorous environment. The densification of the ceramic can be considered as a structural reorganization encompassing bonding of water molecules into a pervasive amorphous phase, containing magnesium-phosphate structural units and involving limited structural rearrangements of the local environment of P and, especially, of Na

Assessment of diclofenac LC50 reference values in juvenile and embryonic stages of the zebrafish (Danio rerio)

The aim of the study was to compare the acute toxicity of diclofenac to juvenile and embryonic stages of the zebrafish (Danio rerio). Acute toxicity tests were performed on the aquarium fish Danio rerio, which is one of the model organisms most commonly used in toxicity testing. The tests were performed using a semi-static method according to OECD guideline No. 203 (Fish, acute toxicity test). Embryo toxicity tests were performed in zebrafish embryos (Danio rerio) in compliance with OECD No. 212 methodology (Fish, short-term toxicity test on embryo and sac-fry stages). The results were subjected to a probit analysis using the EKO-TOX 5.2 programme to determine 96hLC50 and 144hLC50 (median lethal concentration, 50% mortality after a 96 h or 144 h interval, respectively) values of diclofenac. The statistical significance of the difference between LC50 values in juvenile and embryonic stages of Danio rerio was tested using the Mann-Whitney non-parametric test implemented in the Unistat 5.1 programme. The LC50 mean value of diclofenac was 166.6 ± 9.8 mg/L in juvenile Danio rerio, and 6.11 ± 2.48 mg/L in embryonic stages of Danio rerio. The study demonstrated a statistically higher sensitivity to diclofenac (P<0.05) in embryonic stages compared to the juvenile fish

Removal of micropollutants and reduction of biological activity in a full scale reclamation plant using ozonation and activated carbon filtration

Pharmaceutical compounds are found in secondary treated effluents up to μg L-1 levels and therefore discharged into surface waters. Since the long term effects of these compounds on the environment and human health are, to date, largely unknown, implementation of advanced treatment of wastewaters is envisaged to reduce their discharge. This is of particular relevance where surface waters are used as drinking water sources and when considering indirect potable reuse. This study aimed at assessing the removal of organic micropollutants and the concurrent reduction of their biological activity in a full scale reclamation plant treating secondary effluent. The treatment consists of 6 stages: denitrification, pre-ozonation, coagulation/flocculation/dissolved air flotation and filtration (DAFF), main ozonation, activated carbon filtration and final ozonation for disinfection. For that purpose, representative 24-hour composite samples were collected after each stage. The occurrence of 85 compounds was monitored by LC/MS-MS. A battery of 6 bioassays was also used as a complementary tool to evaluate non-specific toxicity and 5 specific toxic modes of action. Results show that, among the 54 micropollutants quantified in the influent water, 50 were removed to below their limit of quantification representing more than 90% of concentration reduction. Biological activity was reduced, depending on the specific response that was assessed, from a minimum of 62% (AhR response) to more than 99% (estrogenicity). The key processes responsible for the plant's performances were the coagulation/flocculation/DAFF, main ozonation and activated carbon filtration. The effect of these 3 processes varied from one compound or bioassay to another but their combination was almost totally responsible for the overall observed reduction. Bioassays yielded complementary information, e.g. estrogenic compounds were not detected in the secondary effluent by chemical analysis, but the samples had an estrogenic effect. The main ozonation formed oxidation by-products of the organic micropollutants but decreased the level of non-specific toxicity and other specific toxic modes of action, demonstrating that the mixture of oxidation by-products was less potent than the mixture of the parent compounds for the considered effects

Effective removal of micropollutants without reverse osmosis processes

This study evaluates the chemical quality of the water produced by a full-scale reclamation plant based on the combination of ozonation and activated carbon filtration and by pilot scale biofilters (sand and activated carbon). The chemical quality was assessed by the quantification of micropollutants (pharmaceuticals and pesticides) along the full scale treatment train and after biofiltration. Results show that the full scale process efficiently removes the targeted micropollutants, the key steps are the main ozonation and the activated carbon filtration. The sand biofilter did not show significant removal of micropollutants whereas as the biological activated carbon filters were able to remove most of the detected micropollutants below their limit of quantification