Recent progress in the synthesis of nanostructured magnesium hydroxide

This review highlights synthetic routes for producing nanostructured magnesium hydroxide and focuses on how these various preparative approaches can produce Mg(OH)2 nanoparticles with controlled size and morphology. Mg(OH)2 nanocrystals with rod-, needle-, hollow tube- or platelet-like morphology can be synthesised by the modification of chemical and physical experimental parameters such as the selection of magnesium precursor, solvent and temperature or by employing surface modifiers and templates. Techniques based on hydrothermal/solvothermal treatments, microwave heating and (co-)precipitation are dominant in the production of Mg(OH)2 at the nanoscale, but other materials design approaches are now emerging. Bulk Mg(OH)2 has been extensively studied over decades and finds use in a wide range of applications. Moreover, the hydroxide can also serve as a precursor for other commercially important materials such as MgO. Nanostructuring the material has proven extremely useful in modifying some of its most important properties – not least enhancing the performance of Mg(OH)2 as a non-toxic flame retardant – but equally it is creating new avenues of applied research. We evaluate herein the latest efforts to design novel synthesis routes to nano-Mg(OH)2, to understand the mechanisms of crystallite growth and to tailor microstructure towards specific properties and applications

Rapid surfactant-free synthesis of Mg(OH)2 nanoplates and pseudomorphic dehydration to MgO

Magnesium hydroxide nanoplates ca. 50 nm in thickness can be prepared over minute timescales via hydrothermal synthesis in a multimode cavity (MMC) microwave reactor. This approach allows ca. 1 g of single-phase Mg(OH)2 to be synthesised in under 3 minutes without the requirement of surfactants or non-aqueous solvents. The hydroxide nanomaterial dehydrates at temperatures >200 K below that of the equivalent bulk material and can be utilised as a precursor for the pseudomorphic synthesis of nanoplates of MgO as investigated by TG-DTA-MS, XRD and SEM measurements. Equally, the pseudomorphic synthesis can be performed by irradiating the Mg(OH)2 nanomaterial with microwaves for 6 minutes to produce single phase MgO

Occupational and environmental exposure to extremely low frequency-magnetic fields in a large group of workers

The aim of this study was to provide: (a) an evaluation of current ELF-MF exposure in workers, (b) the specific contribution of occupational exposure to overall 24-hour exposure, and (c) the representativeness of a Job Exposure Matrix. 543 workers were monitored for 2 whole days using personal meters. Time-Weighted Average (TWA) levels at work, at home, and outside the home (respectively work TWA, home TWA and environmental TWA) were calculated. Tasks were classified according to the ISCO 88 International Standard Classification of Occupations. In about 10% of the entire sample, the monitoring was repeated after 6-9 months. In the whole sample, the median of TWA am during work was 0.14 µT (5°-95° percentiles: 0.04-2.50 µT). Median Home TWA and Environmental TWA were respectively 0.03 (5°-95° percentiles 0.01-0.24 µT) and 0.05 µT (5th-95th percentiles 0.02-0.28 µT). The correlation between TWA values during the first monitoring and the replication was r=0.80. The contribution of occupational exposure to the overall 24-hour exposure was estimated showing that, during working days, about the 60% of exposure is related to work. The variability of individual work TWA among subjects included in the same ISCO 88 task, evaluated using ANOVA, proved significant in 56% of the tasks

Subjective Symptoms in Magnetic Resonance Imaging Personnel: A Multi-Center Study in Italy

Introduction: Magnetic Resonance Imaging (MRI) personnel have significant exposure to static and low-frequency time-varying magnetic fields. In these workers an increased prevalence of different subjective symptoms has been observed. The aim of our study was to investigate the prevalence of non-specific subjective symptoms and of “core symptoms” in a group of MRI personnel working in different centers in Italy, and of possible relationships with personal and occupational characteristics.Methods: The occurrence of 11 subjective symptoms was evaluated using a specific questionnaire with 240 subjects working in 6 different Italian hospitals and research centers, 177 MRI health care and research personnel and 63 unexposed subjects employed in the same departments. Exposure was subjectively investigated according to the type of MRI scanner (≤1.5 vs. ≥3 T) and to the number of MRI procedures attended and/or performed by the personnel, even if no information on how frequently the personnel entered the scanner room was collected. The possible associations among symptoms and estimated EMF exposure, the main characteristics of the population, and job stress perception were analyzed.Results: Eighty-six percent of the personnel reported at least one symptom; drowsiness, headache, and sleep disorders were the most frequent. The total number of symptoms did not differ between exposed persons and controls. Considering the total number of annual MRI procedures reported by the personnel, no significant associations were found nor with the total number of symptoms, nor with “core symptoms.” Only subjects complaining of drowsiness also reported a significantly higher mean annual number of MRI procedures with ≤ 1.5 T scanners when compared with exposed subjects without drowsiness. In a multivariate model, subjects with a high level of perceived stress complained of more symptoms (p = 0.0002).Conclusions: Our study did not show any association between the occurrence of reversible subjective symptoms, including the more specific “core symptoms,” and the occupational exposure of MRI personnel to static and low-frequency time-varying magnetic fields. On the other hand, the role played by occupational stress appears to be not negligible. In further research in this field, measurements of EMF exposure should be considered

Rapid surfactant-free synthesis of Mg(OH)2 nanoplates and pseudomorphic dehydration to MgO

Magnesium hydroxide nanoplates ca. 50 nm in thickness can be prepared over minute timescales via hydrothermal synthesis in a multimode cavity (MMC) microwave reactor. This approach allows ca. 1 g of single-phase Mg(OH)2 to be synthesised in under 3 minutes without the requirement of surfactants or non-aqueous solvents. The hydroxide nanomaterial dehydrates at temperatures >200 K below that of the equivalent bulk material and can be utilised as a precursor for the pseudomorphic synthesis of nanoplates of MgO as investigated by TG-DTA-MS, XRD and SEM measurements. Equally, the pseudomorphic synthesis can be performed by irradiating the MgIJOH)2 nanomaterial with microwaves for 6 minutes to produce single-phase MgO.JRC.F.2-Energy Conversion and Storage Technologie

Nutrient intakes in an Italian population of infants during the complementary feeding period

Objective: To describe the nutrient intakes of an Italian cohort of infants at 6, 9 and 12 months of age. Design: Dietary data were collected using a food diary at three follow-ups (6, 9 and 12 months of age of infants). The infants' dietary data were used to estimate nutrient intakes using the Italian food composition database integrated with data from nutritional labels and the literature. The mean and standard deviation, median and interquartile range, minimum and maximum, and 5th, 25th, 75th and 95th percentiles were calculated for the daily intake of twenty-eight nutrients, with sex differences evaluated using parametric/non-parametric statistical methods. Setting: A prospective population-based birth cohort.SubjectInfants (n 400) living in the urban area of Trieste (Italy). Results: The sex distribution was fairly balanced at each follow-up. The mean daily intakes of energy and the other twenty-seven nutrients considered were greater in males at all follow-ups. In particular, a significant statistical difference was observed in higher male consumption of cholesterol at 9 months and in energy and carbohydrate intakes at 12 months (P < 0·05). The mean daily intake of proteins was greater than that recommended by the Italian Dietary Reference Values at all follow-ups. Conclusions: These preliminary results provide a useful basis for understanding the nutrient intake patterns of infants in this area of Italy during the first year of life

Ethnic background and risk perception in construction workers: development and validation of an exploratory tool

Among occupational sectors, construction is still one of the branches with the highest reported numbers of work-related injuries and diseases, which can even lead to death and in many cases induce permanent health consequences. The vast majority of these occupational injuries and diseases are preventable; accordingly, an improvement in preventive strategies, also through a better knowledge of the main factors involved in these events, is one of the most important objectives for better occupational health and safety in the construction sector. Considering the individual factors associated with a higher risk of work-related adverse health effects in workers, an inadequate perception of occupational risks is among the most relevant issues. Risk perception can vary according to different cultural backgrounds, highly influenced by ethnicity, and it affects the relations between workers in the work environment, and the way by with they undergo the specific occupational tasks and manage risky situations frequently occurring on construction sites. Accordingly, the aim of the authors was to develop a new tool for the assessment of risk perception in construction workers with different ethnic backgrounds