The aim of this study was represented by the definition and testing of a new formulation strategy and the functionality of composite materials, while ensuring the optimization of the relevant properties for the dental restoration processes through the use of precise techniques of characterization, the modification and functionality of the components in view of obtaining results that are characterized by an optimum biomechanical and bioactive relation, in full agreement with the particularities of the dental structure that requires restoration. In view of obtaining new resistant composite structures we made a number of 10 samples including extracted teeth with various losses of dental substance and the structural modifications included 3 types of composites, whose structure was improved by the introduction of inorganic fillings based on hydroxyapatite and silver nanoparticles. All these structures were reinforced with two types of fibers, Reforpost fiber glass kit (Angelus) and Fiber post Schulzer Pre-silanized; With regard to the use of composite structures improved by HA addition, we notice a slight lacunary structure on the SEM images due to the properties of HA, an aspect present at much smaller dimensions in the silver � HA mix. The size of the grains associated with their continuous uniformity and adherence for the fibrillar structure stands out at the samples with hydroxyapatite, the first place as uniformity and adherence going to the composite of the nanofiller technology category.

Recently, there is growing attention on the use of low-cost sorbents in the depollution of contaminated waters. As a consequence, the present work investigates the potential of soy bran and mustard husk as possible sorbent for the removal of arsenic(V) from residual water. Effects of various operating parameters such as: contact time, pH, initial arsenic concentration, pH, sorbent dose, temperature were investigated to determine the removal efficiency of arsenic(V). Thermodynamic parameters that characterize the process indicated that the adsorption is spontaneous and endothermic. The values for the separation factor, R L were less than one which confirms that the adsorption process was favorable. Equilibrium data fitted well to the Langmuir model with a higher adsorption capacity of soy bran (74.07 mg g -1 ) towards arsenic(V) ions than mustard husk (65.79 mg g -1 ). It was found that the pseudo-second order kinetic model was the best applicable model to describe the adsorption kinetic data.

The Podu Iloaiei Dam Lake located on the Bahluet River from Bahlui hydrographic basin, north-eastern Romania, is one of the most important water resources used for aquaculture activities in the region of interest. In the present study, the chemical composition related to water-soluble ions and elements was assessed in both water and sediment samples collected from the area of interest during July 2017 and October 2017, representative months for warm and cold seasons, respectively. Water-soluble ions (H3C2O2−, HCO2−, C2O42−, F−, Cl−, NO2−, Br−, NO3−, SO42−, Li+, Na+, NH4+, K+, and Ca2+) were analyzed by ion chromatography, while inductively coupled plasma mass spectrometry was used to quantify water-soluble fractions of elements (Be, B, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Mo, Ru, Pd, Ag, Cd, Sn, Sb, Te, Ba, Ir, Tl, Pb, Bi, and U). Evidence was obtained on the contributions of both anthropogenic and natural (pedologic) related sources in controlling the chemical composition of the water and sediment samples in the area. Analysis of Piper diagrams revealed the existence of CO32−/HCO3− and Ca2+/Mg2+ as dominant species for the sediment samples. The interest water pool was found to be oligotrophic over the warm period and eutrophic over the cold period. Overall, abundances and the association of chemical species in the area seemed to be controlled by a complex interplay between the water body’s main characteristics, meteorological factors, and anthropogenic activities. Moreover, the present results suggest that precautions should be taken for physicochemical parameter monitoring and prevention acts for surface water quality assurance in order to control the potential negative influence of some chemical parameters on fish productivity. Reported data also have a high potential to be used by experts in the field of developing lake water management policies for a sustainable exploitation of various aquatic systems.

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Chemical analysis was performed on sediment samples collected in two sampling sessions (July and October) from Podu Iloaiei Dam Lake, one of the most important water resources used for aquaculture in north-eastern Romania. The concentration of 15 trace elements (TEs), 8 refractory elements (REs), and 15 rare earth elements (REEs)—determined using inductively coupled plasma mass spectrometry—showed variability largely dependent of the sampling points and collection time. Manganese was the most abundant TE, V and Cr were the most abundant REs, while Ce was one of the most abundant REEs. The cerium negative anomaly and Gd positive anomaly were observed in the Chondrite-normalized distributions. In October, the Ce anomaly showed significant negative correlation with Mn, emphasizing the water body oxidation potential. The identified positive Gd anomaly was most likely associated with the use of Gd-chelating agents in magnetic resonance imaging in Iasi, the largest medical hub in north-eastern Romania. Principal component analysis extracted three factors explaining 96.0% of the observed variance, i.e., rock weathering, leaching from soil surface, contributions from urban stormwater and atmospheric deposition (50.9%), pedological contributions (23.7%), and mixed anthropogenic sources (e.g., traffic, waste discharge, agricultural activities; 21.4%). The evaluation of pollution indices highlighted low and moderate degrees of contamination for most of the elements and a considerable degree of contamination for Cd. Assigned Cd sources included fertilizers and pesticides used in the near agricultural areas or the high traffic road located near the lake. Since contamination of aquatic ecosystems with harmful elements is a human health concern, further monitoring of specific vectors in the food chain of the investigated dam lake will be of the utmost importance.

The performance of a fast and simple analytical procedure for rare earth elements (REEs) quantification from secondary sources was investigated in the present work. Seven silicate-rich certified reference materials (CRMs) in the form of Andesite (JA-1), Basalt (JB-3), Rhyolite (JR-1, JR-2), Granite (JG-2), Granodiorite (JG-3), and Till (TILL-1), were used for the optimization and characterization of the analysis method. The optimized method was used in the analysis of nine mining wastes selected within the ENVIREE project, under the ERA-MIN Program of the 7th Framework, having as the main aim to ensure a policy securing long-term access of REEs secondary sources at reasonable costs. For silicate-rich samples efficient solid dissolution involves sintering with Na 2 O 2 at 460 °C and a sample to oxidizing reagent ratio of 1:6.5. Inductively coupled plasma-mass spectrometry (ICP-MS) was used in the quantification of the REEs with aerosol dilution of samples applied to minimize the salt effect on the plasma and interface regions. The work performed in the present study clearly shows that accurate reports on the REE concentrations from geological matrices also involves as mandatory the estimation of the overall uncertainty from various sources (sample preparation or analyte measurements). In the analysis of geological samples, the proposed analysis method has on average 23% of the overall uncertainty explained by the sample preparation and 77% accounted by the analysis steps. Moreover, the method described by effective, cheap, robust and safe attributes, can be recommended as an accessible alternative to the HF wet digestion method. Although from all the investigated tailings samples, only those from Sweden and Czech Republic can be regarded as potential secondary sources for REEs, investigation of other resources with interest at European level might bring a great benefit in the general attempt to develop an economically viable method for the production of rare earth elements. KeywordsNa 2 O 2 sintering • ICP-MS • Rare earth elements • Secondary sources * Romeo-Iulian Olariu

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