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Polymers involved as adsorbent materials during Eu(III) removal tests were prepared by functionalization of a natural polymer – cellulose, and a commercial one represented by Amberlite XAD7. As extractant, we used tetrabutil ammonium di-hydrogen phosphate (TBAH2P) which is a cheap and environmentally friendly product. Impregnated polymers using a rotavapor system in which the quaternary ammonium salt used as extractant was concentrated on to the used polymer. Later obtained materials were characterized by Fourier Transformed Infrared Spectroscopy (FTIR) and X-Ray electron dispersion (EDX). During experimental test we determine pH, contact time, Eu(III) initial concentration and temperature effect on the functionalized polymers adsorption capacity. Therewith for both functionalized polymers, a comparison was made between the adsorption process characteristics based on kinetics and thermodynamic studies. Keywords: Europium, Cellulose, Amberlite XAD7, Adsorption, Adsorption isotherm

In this paper, we studied the scandium adsorption from aqueous solutions on the surface of low-temperature-activated alumina products (GDAH). The GDAH samples are industrially manufactured, coming from the Bayer production cycle of the Sierra Leone bauxite as aluminium hydroxide, and further, by drying, milling, classifying and thermally treating up to dehydroxilated alumina products at low temperature. All experiments related to hydroxide aluminium activation were conducted at temperature values of 260, 300 and 400 °C on samples having the following particle sizes:

The synthesis and structural characterization of a new liquid crystalline coordination complex based on pentacoordinated Zn(II) metal centre with the coordination fulfilled by the tridentate chelating N^N^N 2,2′;6′,2″-terpyridine ligand and two monoanionic gallates decorated with several long alkyl chains is described. The mesomorphic properties were accurately investigated by small- and wide-angle X-ray scattering studies. Despite the bulky coordination around the metal centre, the complex self-organizes into a smectic phase and, based on the structural and geometrical parameters, a model for the supramolecular organization in the liquid crystalline phase is proposed. Electrochemical investigations showed the importance of the molecular structure of the coordination complex in enhancing its aqueous sensing capacities: the bulky organic ligands form an organic shell separating the metal centres and favouring the redox system through their reduction followed by stripping.

The following review is focused on carrageenan, a heteroglycan-based substance that is a very significant wound healing biomaterial. Every biomaterial has advantages and weaknesses of its own, but these drawbacks are typically outweighed by combining the material in various ways with other substances. Carrageenans’ key benefits include their water solubility, which enables them to keep the wound and periwound damp and absorb the wound exudate. They have low cytotoxicity, antimicrobial and antioxidant qualities, do not stick to the wound bed, and hence do not cause pain when removed from the wounded region. When combined with other materials, they can aid in hemostasis. This review emphasizes the advantages of using carrageenan for wound healing, including the use of several mixes that improve its properties.

This review article explores the telocytes’ roles in inflammatory bowel diseases (IBD), presenting the mechanisms and hypotheses related to epithelial regeneration, progressive fibrosis, and dysmotility as a consequence of TCs’ reduced or absent number. Based on the presented mechanisms and hypotheses, we aim to provide a functional model to illustrate TCs’ possible roles in the normal and pathological functioning of the digestive tract. TCs are influenced by the compression of nearby blood vessels and the degree of fibrosis of the surrounding tissues and mediate these processes in response. The changes in intestinal tube vascularization induced by the movement of the food bowl, and the consequent pH changes that show an anisotropy in the thickness of the intestinal tube wall, have led to the identification of a pattern of intestinal tube development based on telocytes’ ability to communicate and modulate surrounding cell functions. In the construction of the theoretical model, given the predictable occurrence of colic in the infant, the two-layer arrangement of the nerve plexuses associated with the intestinal tube was considered to be incompletely adapted to the motility required with a diversified diet. There is resulting evidence of possible therapeutic targets for diseases associated with changes in local nerve tissue development.

Core–double shell nylon-ZnO/polypyrrole electrospun nanofibers were fabricated by combining three straightforward methods (electrospinning, sol–gel synthesis and electrodeposition). The hybrid fibrous organic–inorganic nanocomposite was obtained starting from freestanding nylon 6/6 nanofibers obtained through electrospinning. Nylon meshes were functionalized with a very thin, continuous ZnO film by a sol–gel process and thermally treated in order to increase its crystallinity. Further, the ZnO coated networks were used as a working electrode for the electrochemical deposition of a very thin, homogenous polypyrrole layer. X-ray diffraction measurements were employed for characterizing the ZnO structures while spectroscopic techniques such as FTIR and Raman were employed for describing the polypyrrole layer. An elemental analysis was performed through X-ray microanalysis, confirming the expected double shell structure. A detailed micromorphological characterization through FESEM and TEM assays evidenced the deposition of both organic and inorganic layers. Highly transparent, flexible due to the presence of the polymer core and embedding a semiconducting heterojunction, such materials can be easily tailored and integrated in functional platforms with a wide range of applications.

Background: Determining the association of neutrophil to lymphocyte ratio (NLR) and clinical disease severity in patients with mild and advanced stage knee osteoarthritis (OA).Method: We analyzed clinical scores and routine hematology panels of 111 subjects with symptomatic knee degeneration: mild OA (66) who underwent knee arthroscopy and advanced OA (45) who had total replacement. Results: Compared to the advanced OA group, the mild OA group was younger (54/67), had fewer females (1.75/5.43), and better scores: Euroqol EQ5D Index (0.50/0.25), VAS (visual analog scale) (65/44); International knee documentation committee subjective knee evaluation form—IKDC (31.6/20.24); Knee disability and osteoarthritis outcome score for joint replacement—KOOSJR (15.5/18.3); and better Kellgren–Lawrence stage (1.3/3.8). Patients with advanced disease had higher NLRs compared to mild OA group and controls: 2.82 versus 1.99 (p = 0.004) and 1.98 (p = 0.002). In the multiple regression model, NLR was only influenced by age (p < 0.001). In the subgroup analysis, for the early OA cases, NLR was significantly dependent to VAS (p = 0.006), IKDC (p = 0.001) and KOOSJR (p < 0.001). Conclusion: NLR was not associated with symptomatic knee OA, as determined by commonly used patient reported outcomes. However, for patients with mild degenerative modifications, EQ5D, VAS, and IKDC were independent predictors of NLR.

In this work, the metal and semiconducting nanoparticles (AgNPs, ZnONPs and AgZnONPs) were phyto-synthesized using aqueous vegetal extracts from: Caryophyllus aromaticus L. (cloves) and Citrus reticulata L. (mandarin) peels. The morphological, structural, compositional, optical and biological properties (antibacterial activity, and cytotoxicity) of the prepared composites were investigated. The most effective sample proved to be AgZnONPs, derived from cloves, with a minimum inhibitory concentration (MIC) value of 0.11 mg/mL and a minimum bactericidal concentration (MBC) value of 2.68 mg/mL. All the other three composites inhibited bacterial growth at a concentration between 0.25 mg/mL and 0.37 mg/mL, with a bactericidal concentration between 3 mg/mL and 4 mg/mL. The obtained composites presented biocidal activity against Staphylococcus aureus, and biocompatibility (on human fibroblast BJ cells) and did not damage the human red blood cells. Additionally, an important result is that the presence of silver in composite materials improved the bactericidal action of these nanomaterials against the most common nosocomial pathogen, Staphylococcus aureus.

The aim of this paper was to produce a new composite material based on carbon and iron oxides, starting from soluble starch and ferric chloride. The composite material was synthesized by simple thermal decomposition of a reaction mass obtained from starch and iron chloride, in an inert atmosphere. Starch used as a carbon source also efficiently stabilizes the iron oxides particles obtained during the thermal decomposition. The reaction mass used for the thermal decomposition was obtained by simultaneously mixing the carbon and iron oxide precursors, without addition of any precipitation agent. The proper composite material can be obtained by rigorously adhering to the stirring time, temperature, and water quantity used during the preparation of the reaction mass, as well as the thermal regime and the controlled atmosphere used during the thermal decomposition. Synthesized materials were characterized using thermogravimetric analysis, X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infra-red spectroscopy (FT-IR). The performances of the obtained material were highlighted by studying their adsorbent properties and by determining the maximum adsorption capacity for arsenic removal from aqueous solutions.

Neuropsychiatric disorders are induced by various risk factors, including direct exposure to environmental chemicals. Arsenic exposure induces neurodegeneration and severe psychiatric disorders, but the molecular mechanisms by which brain damage is induced are not yet elucidated. Our aim is to better understand the molecular mechanisms of arsenic toxicity in the brain and to elucidate possible ways to prevent arsenic neurotoxicity, by reviewing significant experimental, bioinformatics, and cheminformatics studies. Brain damage induced by arsenic exposure is discussed taking in account: the correlation between neuropsychiatric disorders and the presence of arsenic and its derivatives in the brain; possible molecular mechanisms by which arsenic induces disturbances of cognitive and behavioral human functions; and arsenic influence during psychiatric treatments. Additionally, we present bioinformatics and cheminformatics tools used for studying brain toxicity of arsenic and its derivatives, new nanoparticles used as arsenic delivery systems into the human body, and experimental ways to prevent arsenic contamination by its removal from water. The main aim of the present paper is to correlate bioinformatics, cheminformatics, and experimental information on the molecular mechanism of cerebral damage induced by exposure to arsenic, and to elucidate more efficient methods used to reduce its toxicity in real groundwater.

In this paper, the detection protocols for the selective and simultaneous determination of diclofenac (DCF) and tetracycline (TC) in aqueous solutions were developed using a commercial boron-doped diamond electrode modified with graphene oxide and silver, as the Ag/GG/BDD electrode. This electrode presented the possibility to detect only DCF and TC selectively by applying amperometric techniques. However, the pulsed voltammetric techniques operated in optimized working conditions allowed the selective/simultaneous detection of DCF and TC characterized by the improvement of the performance parameters compared to CV. Following the research study related to the electrochemical detection application of the two emerging target pollutants (DCF and TC), the Ag/GR/BDD electrode presented good stability and reproducibility of the results obtained.

The current work focused on the water quality of the Bega and Timis rivers measured by two methods. One of them is the method by which the water was analyzed from a physical-chemical point of view, and the other aimed at quantifying the degree of water pollution by biological methods. In this sense, diatoms were used. In the study, samples of water and diatoms were taken using specific techniques from the Bega and Timis rivers, starting from near the area of their formation until near the border with Serbia. Four sampling points were chosen on the Timis River plus one sampling point on the Surgani River, which is a tributary of the Timis, and six sampling points on the Bega River. The points were chosen specifically, being located downstream of the major sources of pollution. In order to locate the points, information was collected from the studies carried out as part of an extensive monitoring that spanned several years. The abundance and diversity of diatom species were used to calculate the Biological Diatom Index (BDI) and the Saprobity Index (SI). These two indices provide valuable information about organic or heavy metal pollution of water bodies.

To provide people with celiac disease with nutrient-rich gluten-free foods, this study aimed to produce cookies based on buckwheat and baobab flours, which were then subjected to nutritional, phytochemical, and sensory analyses. Results demonstrate that baobab flour (BF) and buckwheat flour (BWF) work together to enhance the nutritional properties of the cookies, in that nutrients that BWF is deficient in, BF provides sufficiently, and vice versa. BF is rich in minerals and carbohydrates, while BWF contains comparatively higher fat and protein levels. As for macro- and micro-elements, potassium (K) is the predominant macro-element in BF and BWF, with 13,276.47 ± 174 mg/kg and 1255.35 ± 58.92 mg/kg, respectively. The polyphenol content is higher in BF than BWF, at 629.7 ± 0.35 mg/100 g as opposed to 283.87 ± 0.06 mg/100 g. Similarly, the total flavonoid content and antioxidant activity of BF was greater than that of BWF, while BF exhibited 213.13 ± 0.08 mg/100 g and 86.62 ± 0.04%, in contrast to BWF, which had 125.36 ± 1.12 mg/100 g and 79.72 ± 0.01%, respectively. BF significantly enhanced the phytochemical composition of the cookies, with the richest sample being BBC3 containing 30% baobab. Buckwheat and baobab have the most abundant phenolic compounds of rutin and epicatechin, respectively. About the analysis of sensory attributes of the cookies, the partial substitution of BWF by BF of up to 20% (BWF3) significantly increased the scores for all attributes. Indeed, the appearance (physical aspect of the cookie: whether it is firm or not) and color (influence of baobab addition on cookie coloration) of the cookies were significantly improved with the addition of BF of up to 20%, but above 20% they were less appreciated. Similarly, up to 20% BF, the texture, flavor, and overall acceptability of the cookies were significantly improved. Taste, on the other hand, was not significantly improved, maybe due to the acidic taste provided by the baobab.

The current study focuses on the synthesis via combustion of dysprosium-doped cobalt ferrites that were subsequently physicochemically analyzed in terms of morphological and magnetic properties. Three types of doped nanoparticles were prepared containing different Dy substitutions and coated with HPGCD for higher dispersion properties and biocompatibility, and were later submitted to biological tests in order to reveal their potential anticancer utility. Experimental data obtained through FTIR, XRD, SEM and TEM confirmed the inclusion of Dy3+ ions in the nanoparticles’ structure. The size of the newly formed nanoparticles ranged between 20 and 50 nm revealing an inverse proportional relationship with the Dy content. Magnetic studies conducted by VSM indicated a decrease in remanent and saturation mass magnetization, respectively, in Dy-doped nanoparticles in a direct proportionality with the Dy content; the decrease was further amplified by cyclodextrin complexation. Biological assessment in the presence/absence of red light revealed a significant cytotoxic activity in melanoma (A375) and breast (MCF-7) cancer cells, while healthy keratinocytes (HaCaT) remained generally unaffected, thus revealing adequate selectivity. The investigation of the underlying cytotoxic molecular mechanism revealed an apoptotic process as indicated by nuclear fragmentation and shrinkage, as well as by Western blot analysis of caspase 9, p53 and cyclin D1 proteins. The anticancer activity for all doped Co ferrites varied was in a direct correlation to their Dy content but without being affected by the red light irradiation.

Bismuth oxides were synthesized from bismuth carbonate using the sol-gel method. Studies have described the formation of Bi2O3, as a precursor of HNO3 dissolution, and intermediate oxides, such as BixOy when using H2SO4 and H3PO4. The average size of the crystallite calculated from Scherrer’s formula ranged from 9 to 19 nm, according to X-ray diffraction. The FTIR analysis showed the presence of specific Bi2O3 bands when using HNO3 and of crystalline phases of “bismuth oxide sulphate” when using H2SO4 and “bismuth phosphate” when using H3PO4. The TG curves showed major mass losses and specific thermal effects, delimited in four temperature zones for materials synthesized with HNO3 (with loss of mass between 24% and 50%) and H2SO4 (with loss of mass between 45% and 76%), and in three temperature zones for materials synthesized with H3PO4 (with loss of mass between 13% and 43%). Further, the thermal stability indicates that materials have been improved by the addition of a polymer or polymer and carbon. Confocal laser scanning microscopy showed decreased roughness in the series, [BixOy]N > [BixOy-6% PVA]N > [BixOy-C-6% PVA]N, and increased roughness for materials [BixOy]S, [BixOy-6% PVA]S, [BixOy-C-6% PVA]S, [BixOy]P, [BixOy-6% PVA]P and [BixOy-C-6% PVA]P. The morphological analysis (electronic scanning microscopy) of the synthesized materials showed a wide variety of forms: overlapping nanoplates ([BixOy]N or [BixOy]S), clusters of angular forms ([BixOy-6% PVA]N), pillars ([BixOy-6% PVA]S-Au), needle particles ([BixOy-Au], [BixOy-6% PVA]S-Au, [BixOy-C-6% PVA]S-Au), spherical particles ([BixOy-C-6% PVA]P-Pt), 2D plates ([BixOy]P-Pt) and 3D nanometric plates ([BixOy-C-6% PVA]S-Au). For materials obtained in the first synthesis stage, antimicrobial activity increased in the series [BixOy]N > [BixOy]S > [BixOy]P. For materials synthesized in the second synthesis stage, when polymer (polyvinyl alcohol, PVA) was added, maximum antimicrobial activity, regardless of the microbial species tested, was present in the material [BixOy-6% PVA]S. For the materials synthesized in the third stage, to which graphite and 6% PVA were added, the best antimicrobial activity was in the material [BixOy-C-6% PVA]P. Materials synthesized and doped with metal ions (gold or platinum) showed significant antimicrobial activity for the tested microbial species.

In recent years, during industrial development, the expanding discharge of harmful metallic ions from different industrial wastes (such as arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, or zinc) into different water bodies has caused serious concern, with one of the problematic elements being represented by selenium (Se) ions. Selenium represents an essential microelement for human life and plays a vital role in human metabolism. In the human body, this element acts as a powerful antioxidant, being able to reduce the risk of the development of some cancers. Selenium is distributed in the environment in the form of selenate (SeO42–) and selenite (SeO32–), which are the result of natural/anthropogenic activities. Experimental data proved that both forms present some toxicity. In this context, in the last decade, only several studies regarding selenium’s removal from aqueous solutions have been conducted. Therefore, in the present study, we aim to use the sol–gel synthesis method to prepare a nanocomposite adsorbent material starting from sodium fluoride, silica, and iron oxide matrices (SiO2/Fe(acac)3/NaF), and to further test it for selenite adsorption. After preparation, the adsorbent material was characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The mechanism associated with the selenium adsorption process has been established based on kinetic, thermodynamic, and equilibrium studies. Pseudo second order is the kinetic model that best describes the obtained experimental data. Also, from the intraparticle diffusion study, it was observed that with increasing temperature the value of the diffusion constant, Kdiff, also increases. Sips isotherm was found to best describe the experimental data obtained, the maximum adsorption capacity being ~6.00 mg Se(IV) per g of adsorbent material. From a thermodynamic point of view, parameters such as ΔG0, ΔH0, and ΔS0 were evaluated, proving that the process studied is a physical one.

The fresco of the Corbii de Piatră Cave Church, dating from the end of the 13th century and the beginning of the 14th century, is applied to the sandstone wall. The degradation of the fresco on large surfaces, with many areas of detachment, has been determined by the infiltration of meteoric water through the sandstone wall on which it is applied, as well as temperature variations, and repeated wetting/drying processes. However, there are small portions of fresco that show good adhesion to the wall. The present research, aimed at providing scientific data to restorers and historians, involves the advanced characterization of a fragment of fresco with good adhesion to the wall and is being carried out by an interdisciplinary team. The stratigraphy, microstructure, compaction defects, chemical composition, and variation of chemical composition in the fresco from the pictorial surface to the mortar-sandstone interface were determined. Correlations were established between degradation processes and wall adhesion.

This paper presents the ecological state of large areas of the Bega and Timis River basins, evaluated based on physical-chemical parameters of water samples in relation to the anthropogenic sources of pollution that occur along these rivers. For the monitoring program, twelve sampling points on the Bega and ten sampling points on the Timis were established in order to determine surface water quality. The potential sources of pollution were highlighted by a downstream vs. upstream analysis. Ecological conditions have been assessed taking into account the national legislation, which transposes the Water Framework Directive on promoting the sustainable use of water based on the long-term protection of water resources. The main sources of pollution were related to the discharges from localities and industry, but the current ecological status of the two water bodies analyzed is in a relatively good state.

The aim of this paper is to provide a simple and efficient photoassisted approach to synthesize silver nanoparticles, and to elucidate the role of the key factors (synthesis parameters, such as the concentration of TSC, irradiation time, and UV intensity) that play a major role in the photochemical synthesis of silver nanoparticles using TSC, both as a reducing and stabilizing agent. Concomitantly, we aim to provide an easy way to evaluate the particle size based on Mie theory. One of the key advantages of this method is that the synthesis can be “activated” whenever or wherever silver nanoparticles are needed, by premixing the reactants and irradiating the final solution with UV radiation. UV irradiance was determined by using Keitz’s theory. This argument has been verified by premixing the reagents and deposited them in an enclosed space (away from sunlight) at 25 °C, then checking them for three days. Nothing happened, unless the sample was directly irradiated by UV light. Further, obtained materials were monitored for 390 days and characterized using scanning electron microscopy, UV-VIS, and transmission electron microscopy.

The aim of this study was to obtain new electrochemically modified electrodes with graphene and Au, Pt, Ag particles considering graphite (GP) and glassy carbon (GC) substrate by applying the chronoamperometry technique in order to develop the detection protocol of tetracycline (TC) considered as emerging pollutant in water, using cyclic voltammetry (CV) technique. The graphite-based substrate used for Ag/ Au/ Pt electrodeposition led to the electrode compositions on which TC oxidation process was not diffusion-controlled and as consequence, TC detection failed. TC detection protocols were developed for all Ag/Au /Pt electrodeposited GC and GC-GP electrodes. Better limits of TC detection was achieved for Ag electrodeposited on GC-GP at the cathodic potential of 0.460 V/SCE.

The sludge management resulting from the urban wastewater treatment plants, from the point of view of circular economy, follows its using as a fertilizer for agricultural lands, degraded lands, in horticulture and forestry. The aim of this paper is the proposing of an alternative way of using the sludge resulting from urban wastewater treatment plants in a sustainable way with a low impact on the environment. The experimental results showed the efficiency of using the stabilized sludge as fertilizer for naturally and anthropically degraded lands and cultivated with Salix sp. The use of stabilized sludge determined the improvement of the nutritional characteristics of the degraded lands, which allowed the growth, development and maintenance of the culture of Salix sp. Considering the characteristics of the cultures and the quantities of metals accumulated by Salix sp., it can be concluded that it has adapted to the environmental and the substrate conditions from the studied degraded lands. The results obtained on the two degraded lands indicate that Salix sp. can be used for its introduction in the economic circuit, both of the salty soils and of the slag and ash deposits.

The plasma electrolytic oxidation (PEO) surface modification technique was employed for improving the mechanical and anti-corrosion properties of the AZ63 magnesium alloy. Different PEO processing times (5, 10 and 20 min) in a 10 g/L NaAlO2 electrolyte, with no other additives, led to the formation of ceramic coatings with mean thicknesses between 15 and 37 microns. Scanning electron microscopy (SEM) showed that the porosity of the coatings decreased with processing time, but an increase in roughness was observed. X-Ray diffraction phase analysis indicated a coating structure composed of majority magnesium aluminate spinel. The corrosion rate of the coated samples decreased with an order of magnitude compared with the bare alloy. The average micro-hardness values of the PEO-coated samples was up to five times higher than those of the AZ63 alloy.

Nowadays, when the supply chain of natural compounds for the production of value-added meat products is limited, the use of by-products from vegetable processing could become an attractive solution, contributing to the concept of circular economy. In this regard, our study investigated the effectiveness of yellow and red bell pepper processing by-products used in dried form (DYBPB, DRBPB) in the sausages recipe, instead of synthetic nitrites, to enhance their oxidative stability during cold storage (4 °C) for 20 days. Two types of nitrite-free sausages were obtained, such as smoked and dried sausages (I) and smoked and blanched sausages (II). Nitrite-free sausage formulations were designed by adding DYBPB and DRBPB at a dose to ensure a total phenolic compounds (TPC) level of 50, 90, 180, and 270 mg gallic acid equivalents (GAE)/kg of processed meat. The formulations developed were compared with control samples of sausages obtained with added sodium nitrite or without any additive. The DYBPB and DRBPB were investigated for total and individual phenolic content, total flavonoid content and antioxidant activity. The obtained sausages were investigated in terms of proximate composition as well as lipid oxidation progression based on specific chemical indices such as peroxide value (PV), p-anisidine value (p-AV), TOTOX index, and thiobarbituric acid (TBA) test during cold storage for 1, 10, and 20 days. The antioxidant activity of DYBPB and DRBPB has been shown to be closely related to their total phenolic content and total flavonoid content. It was found that a higher inhibitory potential against oxidative damage was evidenced in smoked and scalded sausages compared to smoked and dried formulations when the same dose of bell pepper processing by-products was applied. Our results showed that the use of dried bell pepper processing by-products in a dose that provides a TPC of a minimum of 180 mg GAE/kg processed meat for DRBPB and 270 mg GAE/kg processed meat for DYBPB have the potential to ensure lipid oxidative stability during cold storage of sausages for 20 days and can be considered for obtaininginnovative nitrite-free sausage formulations. Bearing in mind that the meat industry is currently looking for natural and sustainable ingredients to replace synthetic ones, our research recommends bell pepper processing by-products as promising substitutes for sodium nitrite to develop value-added meat products.

A metallomesogen based on an Zn(II) coordination complex was employed as precursor to obtain a complex matrix nanoplatform for the fabrication of a high-performance electrochemical hybrid sensor. Three representative paste electrodes, which differ by the weight ratio between Zn(II) metallomesogen and carbon nanotubes (CNT), i.e., PE_01, PE_02 and PE_03, were obtained by mixing the materials in different amounts. The composition with the largest amount of CNT with respect to Zn complex, i.e., PE_03, gives the best electrochemical signal for uric acid detection by cyclic voltammetry in an alkaline medium. The amphiphilic structure of the Zn(II) coordination complex likely induces a regular separation between the metal centers favoring the redox system through their reduction, followed by stripping, and is characterized by enhanced electrocatalytic activity towards uric acid oxidation. The comparative detection of uric acid between the PE_03 paste electrode and the commercial zinc electrode demonstrated the superiority of the former, and its great potential for the development of advanced electrochemical detection of uric acid. Advanced electrochemical techniques, such as differential-pulsed voltammetry (DPV) and square-wave voltammetry (SWV), allowed for the highly sensitive detection of uric acid in aqueous alkaline solutions. In addition, a good and fast amperometric signal for uric acid detection was achieved by multiple-pulsed amperometry, which was validated by urine analysis.

In this work, the synthesis of ordered mesoporous silica of MCM-41 type was investigated aimed at improving its morphology by varying the synthesis conditions in a one-pot process, employing different temperatures and solvent conditions. 2-methoxyethanol was used as co-solvent to ethanol. The co-solvent ratio and the synthesis temperature were varied. The pore morphology of the materials was characterized by nitrogen porosimetry and small angle neutron scattering (SANS), and the particle morphology by transmission electron microscopy (TEM) and ultra-small angle neutron scattering (USANS). The thermal behavior was investigated by simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC) measurements. The SANS and N2 sorption results demonstrated that a well-ordered mesoporous structure was obtained at all conditions in the synthesis at room temperature. Addition of methoxyethanol led to an increase of the pore wall thickness. Simultaneously, an increase of methoxyethanol content led to lowering of the mean particle size from 300 to 230 nm, according to the ultra-small angle scattering data. The ordered porosity and high specific surfaces make these materials suitable for applications such as adsorbents in environmental remediation. Batch adsorption measurements of metal ion removal from aqueous solutions of Cu(II) and Pb(II) showed that the materials exhibit dominantly monolayer surface adsorption characteristics. The adsorption capacities were 9.7 mg/g for Cu(II) and 18.8 mg/g for Pb(II) at pH 5, making these materials competitive in performance to various composite materials.

Aggressive industrial development over the last century involved different heavy metals being used, including high quantities of molybdenum, which need to be treated before discharge in industrial waters. Molybdenum’s market price and industrial applicability make its recovery a big challenge. In the present study the possibility to recover molybdenum ions from aqueous solutions by adsorption on a composite material based on silica matrix and iron oxides—SiO2FexOy—was evaluated. Tests were performed in order to determine the influence of adsorbent material dose, initial solution pH, contact time and temperature over adsorption capacity of synthesized adsorbent material. For better understanding of the adsorption process, the obtained experimental data were modelled using Langmuir, Freundlich and Sips adsorption isotherms. Based on the obtained data, it can proved that the Sips isotherm was describing with better orderliness the studied process, obtaining a maximum adsorption capacity of 10.95 mg MoO42− for each gram of material. By modelling the studied adsorption process, it was proven that the pseudo-second order model is accurately describing the adsorption process. By fitting experimental data with Weber-Morris model, it was proven that MoO42− adsorption is a complex process, occurring in two different steps, one controlled by diffusion and the second one controlled by mass transfer. Further, studies were performed in order to determine the optimum pH value needed to obtain maximum adsorption capacity, but also to determine which are the adsorbed species. From pH and desorption studies, it was proven that molybdate adsorption is a physical process. In order to establish the adsorption mechanism, the thermodynamic parameters (ΔG0, ΔH0 and ΔS0) were determined.

The study of new useful, efficient and selective structures for the palladium ions’ recovery has led to the development of a new series of macromolecules. Thus, this study presents a comparative behavior of two crown benzene ethers that modify the magnesium silicate surface used as adsorbent for palladium. These crown ethers are dibenzo18-crown-6 (DB18C6) and dibenzo 30-crown-10 (DB30C10). The obtained materials were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX) and Fourier-transform infrared spectroscopy (FT-IR). The specific surface area (BET) and point of zero charge (PZC) of the two materials were determined. The palladium ions’ recovery from synthetic aqueous solutions studies aimed to establish the adsorption mechanism. For this desideratum, the kinetic, equilibrium and thermodynamic studies show that MgSiO3-DB30C10 have a higher adsorption capacity (35.68 mg g−1) compared to MgSiO3-DB18C6 (21.65 mg g−1). Thermodynamic studies highlight that the adsorption of Pd(II) on the two studied materials are spontaneous and endothermic processes. The positive values of the entropy (ΔS0) suggest that the studied adsorption processes show a higher disorder at the liquid/solid interface. Desorption studies were also performed, and it was found that the degree of desorption was 98.3%.

The biomedical and therapeutic importance of chitosan and chitosan derivatives is the subject of interdisciplinary research. In this analysis, we intended to consolidate some of the recent discoveries regarding the potential of chitosan and its derivatives to be used for biomedical and other purposes. Why chitosan? Because chitosan is a natural biopolymer that can be obtained from one of the most abundant polysaccharides in nature, which is chitin. Compared to other biopolymers, chitosan presents some advantages, such as accessibility, biocompatibility, biodegradability, and no toxicity, expressing significant antibacterial potential. In addition, through chemical processes, a high number of chitosan derivatives can be obtained with many possibilities for use. The presence of several types of functional groups in the structure of the polymer and the fact that it has cationic properties are determinant for the increased reactive properties of chitosan. We analyzed the intrinsic properties of chitosan in relation to its source: the molecular mass, the degree of deacetylation, and polymerization. We also studied the most important extrinsic factors responsible for different properties of chitosan, such as the type of bacteria on which chitosan is active. In addition, some chitosan derivatives obtained by functionalization and some complexes formed by chitosan with various metallic ions were studied. The present research can be extended in order to analyze many other factors than those mentioned. Further in this paper were discussed the most important factors that influence the antibacterial effect of chitosan and its derivatives. The aim was to demonstrate that the bactericidal effect of chitosan depends on a number of very complex factors, their knowledge being essential to explain the role of each of them for the bactericidal activity of this biopolymer.

The past few decades have shown a worrisome increase in the prevalence of obesity and its related illnesses. This increasing burden has a noteworthy impact on overall worldwide mortality and morbidity, with significant economic implications as well. The same trend is apparent regarding pediatric obesity. This is a particularly concerning aspect when considering the well-established link between cardiovascular disease and obesity, and the fact that childhood obesity frequently leads to adult obesity. Moreover, most obese adults have a history of excess weight starting in childhood. In addition, given the cumulative character of both time and severity of exposure to obesity as a risk factor for associated diseases, the repercussions of obesity prevalence and related morbidity could be exponential in time. The purpose of this review is to outline key aspects regarding the current knowledge on childhood and adolescent obesity as a cardiometabolic risk factor, as well as the most common etiological pathways involved in the development of weight excess and associated cardiovascular and metabolic diseases.

Two paste electrodes based on graphene quantum dots and carbon nanotubes (GRQD/CNT) and one modified with a homoleptic liquid crystalline Cu(I) based coordination complex (Cu/GRQD/CNT) were obtained and morphostructurally and electrochemically characterized in comparison with simple CNT electrode (CNT) for doxorubicine (DOX) detection in aqueous solutions. GRQD/CNT showed the best electroanalytical performance by differential pulse voltammetry technique (DPV). Moreover, applying a preconcentration step prior to detection stage, the lowest limit of detection (1 ng/L) and the highest sensitivity (216,105 µA/mg·L−1) in comparison with reported literature data were obtained. Cu/GRQD/CNT showed good results using multiple pulse amperometry technique (MPA) and a favorable shifting of the potential detection to mitigate potential interferences. Both GRQD-based paste electrodes have a great potential for practical utility in DOX determination in water at trace concentration levels, using GRQD/CNT with DPV and in pharmaceuticals formulations using Cu/GRQD/CNT with MPA.

A new electrochemical sensor designed by modifying the commercial boron-doped diamond (BDD) electrode with graphene oxide (GO) reduced electrochemically and further electrodecorated with silver (Ag), named the Ag/GO/BDD electrode, was selected among a series of the BDD, GOelectroreduced onto BDD (GO/BDD) and silver electrodeposited onto BDD (Ag/BDD) electrodes for the detection of tetracycline (TC) in aqueous solution. The best results regarding the sensitivity of 46.6 µA·µM−1·cm−2 and the lowest limit of detection of 5 nM was achieved using square-wave voltammetry (SWV) operated at the step potential of 5 mV, modulation amplitude of 200 mV and the frequency of 10 Hz in alkaline medium. The application of the alkaline supporting electrolyte-based procedure is limited for water monitoring due to the presence of chloride that interferes with TC detection; however, it can be applied for quantitative determination of pharmaceutical formulations. 0.1 M Na2SO4 supporting electrolyte eliminated chloride interference and can be used for the application of Ag/GO/BDD in practical detection of TC in water.

CuBi2O4 synthesized by thermolysis of a new Bi(III)-Cu(II) oxalate coordination compound, namely Bi2Cu(C2O4)4·0.25H2O, was tested through its integration within carbon nanofiber paste electrode, namely CuBi/carbon nanofiber (CNF), for the electrochemical detection of amoxicillin (AMX) in the aqueous solution. Thermal analysis and IR spectroscopy were used to characterize a CuBi2O4 precursor to optimize the synthesis conditions. The copper bismuth oxide obtained after a heating treatment of the precursor at 700 °C/1 h was investigated by an X-ray diffraction and scanning electron microscopy. The electrochemical behavior of CuBi/CNF in comparison with CNF paste electrode showed the electrocatalytic activity of CuBi2O4 toward amoxicillin detection. Two potential detections, with one at the potential value of +0.540 V/saturated calomel electrode (SCE) and the other at the potential value of −1.000 V/SCE, were identified by cyclic voltammetry, which were exploited to develop the enhanced voltammetric and/or amperometric detection protocols. Better electroanalytical performance for AMX detection was achieved for CuBi/CNF using differential-pulsed and square-wave voltammetries than others reported in the literature. Very nice results obtained through anodic and cathodic currents recorded at +0.750 V/SCE and −1.000 V/SCE in the same time period using a pseudo multiple-pulsed amperometry technique showed the great potential of the CuBi/CNF paste electrode for practical applications in amoxicillin detection in aqueous solutions.

Magnetic iron oxide-silica shell nanocomposites with different iron oxide/silica ratio were synthesized and structurally characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), small-angle neutron scattering, magnetic and N2-sorption studies. The composite that resulted with the best properties in terms of contact surface area and saturation of magnetization was selected for Pb2+ adsorption studies from aqueous media. The material presented good absorption capacity (maximum adsorption capacity 14.9 mg·g−1) comparable with similar materials presented in literature. Its chemico-physical stability and adsorption capacity recommend the nanocomposite as a cheap adsorbent material for lead.

Here, we show that wet impregnation of ZrO2 nanoparticles with 10% and 20% Eu oxide followed by thermal anneal in air above 500 °C produces full stabilization of the tetragonal phase of ZrO2 without evidencing any phase separation. The bare ZrO2 nanoparticles were obtained using three synthetic methods: oil in water microemulsion, rapid hydrothermal, and citrate complexation methods. The homogeneity of the solid solutions was assessed using X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, and advanced luminescence spectroscopy. Our findings show that wet impregnation, which is a recognized method for obtaining surface doped oxides, can be successfully used for obtaining doped oxides in the bulk with good homogeneity at the atomic scale. The limits of characterization technique in detecting minor phases and the roles of dopant concentration and host structure in formation of phase stabilized solid solutions are also analyzed and discussed.