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The main purpose of the present research was to test the ability of nanostructured lipid carriers (NLCs) to efficiently host a hydrophilic polyphenol active with health-promoting activities (caffeic acid (CA)). The caffeic acid-loaded lipid nanocarriers (CA-NLCs) were obtained by high-pressure homogenization technique using a surfactant mixture of Tween 20 and L-α-phosphatidylcholine in association with a lipid mixture of linseed oil, hexadecyl palmitate, and glycerol monostearate. In the first stage, the proportion between surfactant mixture and lipid phase has been varied to obtain appropriate stable nanocarriers. The optimized NLCs have been further loaded with different amounts of caffeic acid and were analyzed in terms of physical stability, size characteristics, and encapsulation efficiency. The antioxidant activity of CA-loaded NLCs and their release behavior have been tested by specific in vitro methods, e.g., ABTS (2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) assay and release experiments, by Franz cell diffusion. The ABTS assay highlighted a high antioxidant potential of the caffeic acid in association with linseed oil. The capacity to capture ABTS cationic radicals was superior for the NLC entrapping an initial amount of 1.5% CA, the level of antioxidant capacity being 91.3%. The in vitro release experiments showed a different release behavior, depending on the initial amount of caffeic acid used. NLC loaded with a higher concentration of CA manifests a gradual slow release, e.g., 45% CA after 24 h of in vitro experiments, while the NLC loaded with smaller concentration of CA assured a higher release in time, around 65%.

A comprehensive study has been carried out to evaluate the extraction of heavy metals mixture (Co2+, Cr3+, Cu2+, Ni2+) from aqueous media by Winsor II non-ionic microemulsion, containing polyoxyethylene (4) lauryl ether as non-ionic surfactant and butyl acetate as organic phase. The extraction mechanism is based on the formation of thiocyanate complexes of metals and their transfer from aqueous to microemulsion phase, either towards the interfacial film of surfactant (Co2+) or into the core of micelles (Cr3+, Cu2+, Ni2+). The value of the distribution coefficient for Co2+ was higher than for the other studied metals and its extraction efficiency was not dependent on the working conditions, showing a maximum value (99.99%) in all cases. By using successive extractions, chromium, nickel and copper ions that remained in the aqueous phase after first extraction were transported into the microemulsion phase, leading to an increase in the extraction efficiency up to 99.99% for chromium and copper, and 85% for nickel. Based on pH influence, a selective extraction of Co2+ and Cr3+ can be achieved, since the cobalt ions were completely extracted into the microemulsion phase at pH = 1, and the chromium ions still remained in the aqueous phase. Keywords: Nonionic microemulsion, Thiocyanate complexes of heavy metals, Simultaneous heavy metals extraction, Microinterfacial effect, Synergism

The treatment of wastewaters with complex load including dyes and heavy metals is a subject of paramount importance since trace amounts of these compounds lead to an enormous pollution problem. The present research proposes an innovative, fast and efficient microemulsion system for simultaneous extraction of a mixture of dyes (Crystal violet and Rhodamine B) and heavy metals (cobalt(II) and copper(II) ions) from such wastewaters. The used microemulsion is an environmental friendly system containing Brij 30 as nonionic surfactant and butyl acetate as organic phase. The effect of various parameters with significant influence on the dye and metals extraction efficiencies has been investigated in order to find out the optimal compositions for an efficient extraction of dyes – heavy metals mixture from aqueous media. The results show that the optimum extraction conditions for this system corresponds to pH = 5, a water to oil volumetric ratio equal to 9 and a concentration of the complexing agent equal to 2 mol/L.

This work reports the semiquantitative laboratory chemical procedures developed for some Rare Earth Elements (REE) extraction and concentration from coal bottom ash (BA), including recycling the recovered valuable components. This preliminary assessment applied in case of 25 coal BA samples of Ceplea Valley landfill of Romania describes the chemical methods by using digestion with nitric acid coupled with microemulsion assisted extraction procedure. The enrichment of REE by concentrated nitric acid followed by water washing proved to be an adequate approach since water recovers 29.42% of metals comparing to that extracted by the total phase (ac + aq). The REE concentration process achieved by precipitation with NaOH, at different pH values, shows to be almost completely in the fraction at pH ≈ 0 and 3. The statistical outlook coefficient Coutl shows that evaluation of REE concentration in acid/aqueous solution falls into the “promising” field for their recovery by chemical procedures. Optimal microextraction was obtained by coupling microemulsion Winsor II ternary system consisting in Brij 30/AcOEt:AcOBu/metal ions solution, with citric acid as complexing agent. Results confirm that recovery of lanthanides as nanoparticles from microemulsion system yields over 85%. Optical characterization of oxide nanoparticles suggested applications such as for energy efficient buildings, photo-catalysts for water remediation or thin films for photonic optical devices. The ash residue can be also recycled as an alternative raw material for building materials production.

The efficiency of a new eco-friendly microemulsion system based on Polyoxyethylene (4) Lauryl ether/Butyl acetate/Water was compared to that of Polyoxyethylene (4) Lauryl ether/Ethyl acetate/Water. The two systems were analyzed with respects to the recovery of monocomponent or multicomponent targeted hydrophilic compounds (Crystal Violet dye and Co2+ ions) from polluted liquid media. In order to determine the optimal recovery conditions, the influence of surfactant and dye concentrations on the volumetric ratio of aqueous phase to microemulsion (F) was studied. Furthermore, heavy metal concentrations and distribution coefficients were analyzed using the ternary and pseudo-ternary phase diagrams. The results showed that the Polyoxyethylene (4) Lauryl ether/Butyl acetate/Water system was more efficient compared to the Polyoxyethylene (4) Lauryl ether/Ethyl acetate/Water system in the recovery of hydrophilic compounds for both monocomponent (Crystal Violet dye or Co2+) and multicomponent (Crystal Violet dye and Co2+) systems. A recovery efficiency of 90.6% for dye and heavy metal ions was obtained using the Polyoxyethylene (4) Lauryl ether/Butyl acetate/Water microemulsion system.

This paper proposes an innovative solution for the efficient dye degradation from water treatment plant effluent, using microemulsion assisted photodegradation without the addition of a solid catalyst. Total photodegradation of dyes was achieved using for the first time a process based on combined photocatalytic effects of the water/oil interface processes and the potential activity of ethyl acetate as a UV initiator. The catalytic effect of nanostructured fluids based on the carboxylic oil phase is an absolute scientific premiere, and microemulsion assisted photodegradation processes open a new direction to pollutants photodegradation approach, exceeding the performances of both homogeneous and heterogeneous catalysis. The phenomenological modeling, with and without initiator, on both homogeneous and heterogeneous systems showed that the photodegradation of cationic and anionic dyes in a water/nonionic surfactant/ethyl acetate microemulsion is a radical process based on a chain reaction scheme. The compl...

A class of fluorescent Au@SiO2 and SiO2@Au core–shell fluorescent nanoparticles has been synthesized using microemulsion assisted sol–gel method coupled with photoreduction reaction as an easy, rapid and versatile “one-pot” procedure. In the case of Au@SiO2-RhB (gold nanoparticles core coated with silica-Rhodamine B shell) different silica shell sizes were obtained ranging from 3 to 116 nm, while for RhB-SiO2@Au (Rhodamine B-silica core coated with gold nanoparticles shell) the size of gold shell falls within 3–38 nm interval. The synthesized core–shell nanoparticles have been characterized by a variety of techniques including Dynamic Light Scattering (DLS), High-Resolution Transmission Electron Microscopy (HR-TEM) coupled with Energy-Dispersive X-ray spectroscopy (EDX), Scanning Electron Microscopy (SEM), X-ray Diffractometry (XRD) and UV–VIS–NIR spectroscopy to confirm the size, shape, stability and topographic structure of the both core–shell nanostructures. The fluorescence enhancement of Rhodamine B (RhB) dye in the presence of gold nanoparticles (AuNPs) was demonstrated for the core–shell nanostructures synthesized in the present study, for different silica or gold shells. These interesting fluorescent core–shell nanoparticles provide ideal candidates for a variety of applications in materials science, biology, catalysis and optical fields.

The association of numerous advantages of natural active compounds (from vegetal and herbs) and endogenous lipid in the same delivery system is a straightforward approach for the development of safe and better tolerated anti-obesity therapy. In the present study we envisage a novel concept for obesity therapy, devoted to the development of innovative lipid nanostructured formulas with improved gastric tolerability and enhanced specificity in adipose cells targeting. For this purpose, an anti-obesity herbal active from red pepper extract – Capsaicin (Cap) and an endogenous lipid regulator of appetite – oleoylethanolamide (OEA) or a structural analogue of OEA – Phenylalaninol oleamide (PAO), are simultaneously integrated within the same delivery system – nanostructured lipid carriers (NLC) prepared with linseed oil that has anti-inflammatory and hypotriglyceridemic properties. The NLC-OEA/PAO-Cap presented mean diameters under 200 nm, size that allow an efficient uptake of actives by enterocytes and lead to an extended biological action of all actives – Cap, OEA/PAO and linolenic acid. NLC revealed a polidispersity index ranging from 0.16 to 0.22, which represents a narrow dispersion around mean size and suggests an adequate unimodal behavior. The two types of NLC co-loaded with Cap and OEA/PAO were both negatively charged, with zeta potentials of −42.8 mV and −58.5 mV that offered a guarantee for an excellent stability of NLC in time. Despite to the competition between the accommodations of both actives into the lipid core of nanocarriers, the entrapment efficiency exceeds 92% for OEA/PAO and is ranged between 71 and 82% for Cap. In the presence of NLC-OEA/PAO-Cap, ABTS+⁎ inhibition proceeded in a Capsaicin concentration dependent manner and was dependent on the type of NLC formulation. A remarkable radical-scavenging activity against ABTS+⁎ was determined for Cap and OEA based-NLC. The in vitro release demonstrated that NLC played an important role on the delay of Cap dissolution; the NLC have ensured a slow release of Cap, eg only 21% Cap was released after 24 h of in vitro experiments. The in vivo pharmacological evaluation has revealed that the NLC-OEA/PAO-Cap treatment resulted in a body weight decrease and improves the lipid and glucose profile, as compared to the obese mice batch. Obesity mice treated with NLC-OEA exhibited a weight loss of ~15% and ~10% weight loss for NLC-POA, after 10-days treatment. Administration of NLC-OEA/PAO-Cap to the Albino Swiss mice led to significant decrease of glucose level (e.g. 117.4 mg/dL for NLC-OEA-Cap treated mice versus 213.9 mg/dL for obese mice batch) and exhibited a desired decrease effect of triglyceride (e.g. 71.1 mg/dL for NLC-OEA-Cap versus 129.5, for obese batch). Moreover, the cholesterol values have been lowered to almost half from the value determined for the control batches. Overall, study highlights that using appropriate lipid mediators in association with an herbal anti-obesity active, both formulated into lipid nanocarriers, could enhance the therapeutic response in the obesity treatment.

Pollution abatement of wastewaters discharged from textile industry remained a serious environmental problem susceptible for further technological improvements. This study proposes an innovative, fast and efficient microemulsion system for removal of ionic dyes mixture from such wastewaters. A series of physical–chemical parameters (initial dye concentration, pH, salt and sequestrant concentrations) with significant influence on the dye removal efficiency of water/nonionic surfactant/ethyl acetate ternary system has been studied in order to find out the optimal compositions for an efficient extraction of cationic and anionic dyes from aqueous media. The optimum extraction conditions for this system correspond to pH > 5, surfactant concentration around 8% (w/w) and organic phase concentration around 13% (w/w), resulting in extraction efficiencies around 90%. By adding sodium chloride (concentration > 60 g/L) in the ternary system the removal efficiency was improved.

The interactions of two ionic dyes, Crystal Violet and Methyl Orange, with different charged surfactants and also with a nonionic surfactant were investigated using surface tension measurements and visible spectroscopy in pre-micellar and post-micellar regions. It was found that for the water dominant phase systems the dye was localized between the polar heads, at the exterior of the direct micelle shells for all the systems. For the oil dominant phase systems, in case of the same charged dye/surfactant couples, the dye was localized in the micelle shell between the hydrocarbon chain of the surfactant nearby the hydrophilic head groups while for nonionic surfactant and oppositely charged dye/surfactant, localization of dye was between the oxyethylenic head groups towards the interior of the micelle core. Mixed aggregates of the dye and surfactant (below the critical micellar concentration of cationic surfactant), dye-surfactant ion pair and surfactant-micelles were present. The values of equilibrium constants (for TX-114/MO and TX-114/CV systems were 0.97 and 0.98, respectively), partition coefficients between the micellar and bulk water phases and standard free energy (for the nonionic systems were −12.59 kJ/mol for MO and −10.97 kJ/mol for CV) were calculated for all the studied systems. The partition processes were exothermic and occurred spontaneously.

The work aims to simulate in vitro the antioxidant activity of four phytoestrogen type isoflavones, whose effects are closer to those of estradiol (daidzein, formononetin, genistein, biochanin A) in biomimetic environments (in lecithin lipidic bi-layers and on silver nanoparticles), using the chemiluminescent system luminol–hydrogen peroxide, in phosphate buffer, pH 7.4. The contribution of a carrier protein, human serum albumin (HSA), to the antioxidant activity of these isoflavones has also been investigated. The rate of the fluorescence quenching of HSA by isoflavone as well as the binding constant of isoflavone to HSA, in both lecithin lipidic bi-layers and on silver nanoparticles, has also been investigated by fluorescence spectroscopy. The results are discussed with relevance to the oxidative stress process.

The study describes an ideal approach to increase the co-encapsulation of two water and lipid-soluble drugs in the same delivery system. The main purpose is represented by the exploitation of oil fractions isolated from amaranth seeds for the development of squalene-based nanocarriers able for a dual release of one antitumor drug, pemetrexed and one bio-flavonoid, hesperidin. The co-encapsulated nanocarriers presented unique nanoassembly morphology and showed excellent stability against aggregation. A delimited repartition of both actives, mainly in oily nanoconfinements of lipid nanocariers has been indicated by scanning calorimetry. The entrapment efficiency study revealed a great encapsulation effect with values reaching 94% for hesperidin and 89% for pemetrexed. These values are associated with a high ability of squalene-nanocarriers to capture free radicals. The greatest antioxidant activity was determined for nanocarriers that co-encapsulate 1.4% drugs, e.g., 97.3 and 98.2%. In vitro co-release tests demonstrated that pemetrexed and hesperidin were gradually released despite of their different lipophilicity. The most concentrated squalene fraction assures a slower release of both actives. The cumulative results showed that the applied strategy is a promising approach to improve the performance of medical treatments used to prevent and treat diseases associated with tumor and oxidative stress.

Drug delivery systems based on natural drug carriers have become important due to their non-toxicity and biodegradability. We report here the synthesis and characterization of new biomaterials like sponges containing collagen, chloramphenicol and glutaraldehyde for dentistry. All sponges favour water absorption, showing that increasing the glutaraldehyde content leads to an increase in water uptake. The sponges showed resistance to collagenase degradation and strong activity against the tested bacteria. Kinetic data showed non-Fickian diffusion behaviour with a slow release rate. Taking into account that dental drug delivery systems exhibit low water absorption, slow drug release, high content of drug delivery, good antimicrobial activity, and resistance to enzymatic action, the results obtained in this study indicate the optimal content of glutaraldehyde for the sponge as being 0.5%. The properties of the designed formulations demonstrate that these sponges could be adequate for the treatment and/or the prophylaxis of infected lesions at the dental level.

Vegetable oils are well-known for their beneficial health effects, mainly due to their antioxidant activity, which is maintained or enhanced when they are encapsulated at nanoscale. This study aims to design new nanostructured lipid carriers (NLCs) containing various vegetable oils and their combinations in order to obtain efficient formulations with UV protection performance and antioxidant activity. Pomegranate seed oil, wheat germ oil, blackcurrant seed oil, sesame seed oil, carrot root oil, raspberry seed oil and rice bran oil were used for obtaining NLCs, as carriers for a photoprotective agent that absorbs the UVA radiation: diethylamino hydroxybenzoyl hexyl benzoate. The NLCs were characterized by mean particle size, physical stability over time, and entrapment efficiency of the UVA filter. The UV protection performance was assessed using both in vitro sun protection factor (SPF) and the UVA protection factor (UVAPF). The antioxidant activity was determined by chemiluminescence analysis. All vegetable oils used led to the development of appropriate NLCs, having mean particle sizes ranging between 100 nm and 145 nm and good physical stability with zeta potential values less negative than −35 mV. The UV protection factors were evaluated on the individual vegetable oils and on cream formulations based on NLCs. Out of the seven cream formulations, the best UV protection was assured by the pomegranate seed oil based cream resulting in a SPF of 4.1 and an UVAPF of 7.8. Knowing that a synergistic interaction can occur among the active compounds of different oils, new NLCs were developed by using a mixture of pomegranate seed oil and one of the other oils. The NLCs based on pomegranate seed oil combined with wheat germ oil have shown the best entrapment efficiency (70%) and photoprotection (SPF of 5.1 and a UVAPF of 9.5). All vegetable oils showed a good antioxidant activity, which was improved by their incorporation into NLCs. The results have shown that vegetable oils and especially their combinations can be used as renewable raw materials in designing effective and eco-friendly photoprotective nanostructured formulations.

The work aims to simulate in vitro the effects caused by oxidation of five hydroxyflavones (HF) (some typical models of flavonols), (3-HF, 6-HF, 7-HF, 3,6-diHF and 3,7-diHF) on silver nanoparticles (SNPs) using the chemiluminescent system luminol–hydrogen peroxide, in phosphate buffer, pH 7.4. The contribution of bovine and human serum albumins to the antioxidant activity of the mentioned flavones, and the effect on the SNPs support, in the chemiluminescent system luminol–hydrogen peroxide, has been also investigated. The results are discussed with relevance to the oxidative stress process.

This paper presents the spectral and electrochemical properties correlated to antioxidant character attributed to anthocyans: Pelargonidin-3-O-Glucoside, Cyanidin-3-O-Glucoside, Delphinidin-3-O-Glucoside, Peonidin-3-O-Glucoside, Malvidin-3-O-Glucoside. The Anthocyans were obtained and purified from natural selective hydroalcoholic extracts using HPLC chromatography. A series of determinations through the chemical voltammetry method were performed in view of identifying the anthocyanins’ oxidation and reduction potentials. These determinations were performed in electrochemical environments with different polarities and pH, in N, N-Dimethylformamide–Ethanol-Hydrochloric acid–Water systems. The results obtained offered data regarding the stability of anthocyans in the respective media. For Pelargonidin-3-O-Glucoside we performed detailed UV-VIS spectro-electrochemical measurements, using an optically transparent thin layer electrochemical cell. The results of these determinations offered information regardin...

The principal aim of the present study was to develop new safe and highly antioxidant nanostructured lipid carriers loaded with sea buckthorn extract. Three vegetable oils — grape seed oil, sea buckthorn oil and St. John's wort oil ( Hypericum perforatum oil) — were used as matrix components and the modified high shear homogenization technique has been employed for the synthesis of nanostructured materials. The effect of these oils on the antioxidant and antimicrobial activities of loaded sea buckthorn extract — nanostructured lipid carriers — has also been studied. For this purpose, a combination of two solid lipids: cetyl palmitate with glyceryl stearate and lecithin/block copolymer has been used. The obtained nanostructured lipid carriers have been characterized for the particle size and zeta potential by means of dynamic light scattering measurements. The nano-dimension morphology of loaded nanostructured lipid carriers was confirmed by transmission electron microscopy. Their crystallinity measured by differential scanning calorimetry has revealed a high disordered lipid matrix. The properties of sea-buckthorn-extract-loaded nanoparticles have been evaluated by an appropriate in vitro analysis (chemiluminescence method). The presence of the three vegetable oils influences extensively the antioxidant properties of the developed nano-formulations, as has been demonstrated using the chemiluminescence technique. The antimicrobial activity of the studied nanostructured lipid carriers, analyzed by the diffusion disc method, shows in most of the samples a high efficiency against Escherichia coli bacteria.

Due to their unique features, most nanostructured lipid carriers (NLCs) in association with vegetable oils that exhibit UV filtering properties and bioactivity could be used in many cosmetic formulations. Therefore, in this work, a new application of pomegranate seed oil (PSO) in the cosmetic sector was developed, based on the synthesis of bioactive lipid nanocarriers loaded with various UV filters by the hot high pressure homogenization technique. To get broad spectrum photoprotection, different UVA and UVB filters have been used (Avobenzone — AVO, Octocrylen-OCT, Bemotrizinol — BEMT). The influence of the solid lipids combined with PSO on the particle size, physical stability and entrapment efficiency was investigated using 8 nanocarrier systems. An improved physical stability and an appropriate size were obtained for NLCs prepared with Emulgade, carnauba wax and PSO (e.g. −30.9÷-36.9 mV and 160÷185 nm). NLCs showed an entrapment efficiency above 90% and assured slow release rates of UV filters, especially for BEMT (5%). The developed nanocarriers have been formulated into safe and effective sunscreens containing low amounts of synthetic UV filters coupled with a high percent of natural ingredients. The highest SPF of 34.3 was obtained for a cream comprising of 11% PSO and 3.7% BEMT

The vegetable oils and extracts known for their beneficial effects should be identified and used in various forms for the development of new healthy products. This study was designed to provide further investigation on new nanocarriers made with hempseed oil or a blend of amaranth and hempseed oils, for a concomitant encapsulation and release of the carotenoids enriched plant extract. The size of plant extract loaded lipid nanocarriers ranging between 109 and 130 nm was found to be less influenced by the different ratios of hempseed and amaranth oils. For all of the synthesized nanocarriers, zeta potential values were negative (−33.4 ÷ −38.1 mV). The scanning calorimetry study has shown that lipid nanocarriers have favorable lattice defects for plant extract encapsulation. Entrapment efficiency results revealed an increase of carotenoids entrapment from 57.6 to 83.5% as the amaranth oil percent has been increased. High ability to scavenge the free oxygenated radicals was distinguished for all free and loaded nanocarriers. The level of antioxidant activity increase was proportional to the extent of vegetable oil and was ranging between 93.4 and 98.1%. The nanocarriers made with amaranth and hempseed oils have shown a more sustained release over time than those prepared with hempseed oil only in association with solid lipids. Practical applications: The applicability of lipophilic plant extracts enriched in bioactive compounds encounters serious problems in the food and pharmaceutical sector due to poor bioavailability. Using the concept of exploiting natural resources in combination with soft nanotechnology, valuable bioactive vegetable mixtures could be formulated into solid colloidal nanoparticles. The bioavailability and the therapeutic benefit of hempseed and amaranth oils in association with lipophilic plant extract enriched in carotenoids are increased by incorporation into the same nanostructured formulation. These formulations result in unique precursors of health products, particularly for nutraceutical industry. The lipid nanocarriers based on natural compounds offer potential applications as natural, low cost and innovative delivery systems to improve quality and extend shelf-life of food products. The developed vegetable based lipid nanocarriers offer advantages of a minimum carrier cytotoxicity, good storage stability, synergistic effects, antioxidant and sustained release, easy to scale up production. Lipid nanocarriers made with hempseed and amaranth oils and loaded with carotenoids extract from marigold plant. Influence of vegetable oils on in vitro antioxidant activity of developed lipid nanocarriers.

After oxidation of tannins (Tannins 1–3) extracted from grape seeds, Tanoxil compounds with increased solubility and enhanced antioxidant activities were synthesized. In this research, ABTS+· assay and a chemiluminescence method were used for antioxidant measurement of hydrophilic compounds (Tanoxils 1–3).It was observed that the antioxidant activity (AA, %) is very similar for the three samples, while at the same time AA is quite high (93.16%–96.48%). The percentage of inhibition by ABTS+· is higher for Tanoxil 2 (96.4%) as compared to Tannin 2 compound (14.34%). Moreover, the total content (TCF) of carboxyl and phenolic groups was investigated. TCF values, determined for Tanoxil products, revealed a double (Tanoxil 1) or triple (Tanoxil 2) increase as compared to the value of the TCF of Tannin 1. Tanoxil products represent an interest for future research as they have a high AA (96.4%) and the content of acidic groups is significant (TCF, 0.191 meq g−1).

In this paper, the preparation and characterization of some novel nanostructured lipid carriers for drug delivery are reported. They are obtained by mixing two solid lipids, cetyl palmitate and glyceryl stearate, with three types of vegetable oils: grape seed oil, St. John's wort oil ( Hypericum perforatum oil) and sea buckthorn oil. In order to increase their antioxidant and antimicrobial properties, they are co-loaded with green tea extract by using a modified high shear homogenization technique. Size distribution and polydispersity index of the developed nanostructured lipid carriers determined by the dynamic light scattering, and corroborated with the results obtained by the transmission electron microscopy analysis, confirmed that the structures obtained are at nanoscales. The crystallinity behavior of the prepared nanostructured lipid carriers has been studied by differential scanning calorimetry; zeta potential measurements show that all loaded nanostructures present excellent physical stability. Their antioxidant and antimicrobial properties evaluated by an appropriate in vitro analysis using the chemiluminescence method, and the diffusion disc method, respectively, show that green tea extract could be utilized as a valuable natural source of antioxidant and antimicrobial agent. These new nano-formulations proved to have significant potential for nutritional and pharmaceutical applications.

The aim of this research was to develop advanced lipid nanocarriers based on renewable vegetable resources (rice bran oil and raspberry seed oil) that possess self-antioxidative properties, having advantages in terms of minimal side effects and exhibiting the ability to simultaneously co-encapsulate and co-release two active compounds. The focus has been oriented towards developing safe cosmetic formulations with broad-spectrum photoprotection based on these new lipid nanocarriers that contain large amounts of vegetable oils and low concentrations of synthetic UVA and UVB filters (butyl-methoxydibenzoylmethane - BMDBM and octocrylene - OCT). The lipid nanocarriers have a spherical shape and show good physical stability, with a zeta potential in the range of -25.5 to -32.4 mV. Both vegetable oils play a key role in the preparation of efficient nanocarriers, leading to a less ordered arrangement of the lipid core that offers many spaces for the entrapment of large amounts of BMDBM (79%) and OCT (90%), as wells as improved antioxidant activity and UV absorption properties, particularly for the lipid nanocarriers prepared from rice bran oil. By formulating the lipid nanocarriers into creams containing only 3.5% of the UV filters and 10.5% of the vegetable oils, the resulting sunscreens exhibited improved photoprotection, reflecting up to 91% and 93% of UVA and UVB rays, respectively. A new direction of research achieved by this study is the multiple release strategy of both UV filters from the same lipid nanocarrier. After 24 hours, a slow release of BMDBM (less than 4%) and OCT (17.5%) was obtained through a Fick diffusion process. This study demonstrates a significant advance in the areas of both nanotechnology and cosmetics, developing safer cosmetic formulations that possess broad antioxidant, photoprotective and co-release effectiveness due to the existence of a high content of nanostructured vegetable oils combined with a low amount of synthetic UV filters in the same carrier system.

Dye photodegradation of fullerene-modified silica materials has been investigated for ecological purposes. The highly efficient photodegradation process for the removal of 45% and 90% methylene blue dye under VIS and UVC light irradiation, respectively has proved the potential photo-degradative properties of these fullerene-modified silica materials. The key parameters that control photodegradation are quite high specific surface area (395 m 2 /g) of silica support, very low content of C 60 (0.04%) and the size effect promoted by homogeneous dispersion of C 60 nanoclusters (10 nm) in SiO 2 support. The enhancement of photodegradation efficiency is interpreted in terms of band gap energy and zeta potential values of the nanostructures under study.

Collagen sponges are known to be safe and well-characterized supports for drug delivery systems. The aim of this study was to prepare, characterize and test drug delivery systems that contain collagen as support and niflumic acid as a drug. Type-I collagen and niflumic acid gels were cross-linked with different concentrations of glutaraldehyde and then freeze-dried in order to obtain collagen matrices (spongious form). The physical-chemical properties were assessed by infrared spectroscopy (FTIR) and morphological properties were evaluated by water absorption. Niflumic acid release from cross-linked collagen spongious forms was also investigated and the kinetic mechanism was discussed.

The coencapsulation of two UV filters, butyl-methoxydibenzoylmethane (BMDBM) and octocrylene (OCT), into lipid nanocarriers was explored to develop stable cosmetic formulations with broad-spectrum photoprotection and slow release properties. Different types of nanocarriers in various concentrations of the two UV filters were tested to find the combination with the best absorption and release properties. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) have been the two types of lipid nanocarriers used. The NLCs were based on either medium chain triglycerides (MCT) or squalene (Sq). The following physicochemical properties of the nanocarriers have been evaluated: particle size, morphology, zeta potential (ZP), entrapment efficiency, loading capacity, and thermal behavior. The nanocarriers have been formulated into creams containing low amounts of UV filters (2.5% BMDBM and 1% OCT). The best photoprotection results were obtained with the cream based on NLCs prepared with MCT, having a sun protection factor (SPF) of 17.2 and an erythemal UVA protection factor (EUVA-PF) of 50.8. The photostability of the encapsulated BMDBM filter was confirmed by subjecting the nanocarriers-based creams to in vitro irradiation. The prolonged UV-protection efficacy was coupled with a slow in vitro release of the synthetic UV filters, which followed the Higuchi release model.

The objective of this investigation was to develop solid lipid nanoparticles (SLNs) of umbelliferone by means of a high shear homogenization technique and to evaluate the efficiency of SLN systems in preserving and enhancing antioxidant activity of the flavonoid active component. The aqueous SLN dispersions combine two structural types of lipid compounds and different types of emulsifiers including a mixture of monoalkyl polyoxyethylene sorbitan with a block copolymer and lecithin. The assessment of umbelliferone stability in aqueous SLN dispersions, the size distribution of lipid nanoparticles loaded with umbelliferone (by DLS technique), as well as the structural changes (FT-IR spectroscopy and differential scanning calorimetry) of these lipid nanomatrices have been investigated. Moreover, the influence of umbelliferone concentration onto entrapment efficiency and antioxidant properties were clearly evidenced on four kinds of lipid nanoparticles. The umbelliferone-loaded SLN prepared with polyethylene g...

Hybrid sol-gel films containing Rosemary extract nanoclusters embedded into hybrid silica network have been successfully synthesized using the sol-gel procedure by exploiting the template route, in association with an adequate spin-coating method. Formation of film precursor sols and effect of selected amounts of octyl trimethoxysilane and ethyl oleate succinic anhydride into the starting acid sols on the sol-gel product size have been evaluated by dynamic light scattering technique. The spectral characteristics of hybrid organic–inorganic films have shown that the multiple functional groups from Rosemary extract associated with residual Si–OH groups can cause the increase in the degree of physical interaction. The effect of hybrid sols meaning the silica precursors molar ratio and template concentration on the fluorescence of hybrid films has been also investigated. The fluorescence properties of synthesized films were found to be dependent on template and natural extract concentration. A higher amount of template resulted in doubling the fluorescence intensity in the 400–480 nm domain. The microstructural characteristics of the hybrid films revealed by atomic force microscopy have shown a homogeneous surface morphology with cluster-like structure. Hybrid silica films exhibit a periodic structure with cluster size less than 150 nm.

The sol–gel encapsulation of labile substances with specific properties and recognition functions within robust polymer matrices remains a challenging task, despite the considerable research that has been focused on this field. Numerous studies have been reported in the field of sol–gel processes regarding different physical and chemical packing of sensitive biomolecules encapsulated in silica matrix. In this paper the classical sol–gel synthesis has been used under mild conditions in order to minimize denaturizing effects on encapsulated active vegetable extracts from flavones class. The silica templated matrix was obtained by using two types of surfactants with different alkyl chain (didodecyldimethyl-ammonium bromide and trioctadecylmetilammonium bromide) as structure-directing agents for the silicon oxide framework. An organic precursor of silicic acid (triethoxymethylsilane) has been used and it was processed by competitive hydrolysis and polycondensation reactions under controlled directions assured by the presence of oriented template. Silica materials thus obtained are used for encapsulation of two flavonoid samples containing as active principles two sources: rutin and a vegetable extract from Begonia plant. The synthesis of encapsulated nanocompounds has been achieved taking into consideration the specific interaction between the colloidal gel precursors and molecular structures of selected biomolecules. The main objective was to improve the encapsulation conditions for specific biomolecules, searching for the highest stability and functionality without loosing the quality of the flavonoid properties, particularly optical properties like fluorescence. The structural properties of the encapsulated samples have been studied by FT-IR and UV–VIS spectroscopy, thermal analysis and SEM/EDX analysis. The fluorescence experiments showed that, in the case of all four encapsulated samples, the fluorescence spectra manifest a significant increase in intensity signals, with more than 10 times for individual flavonoid and 50 times for Begonia extract. This behaviour are mainly assigned to the physical interaction of flavonoid molecules with the residual hydroxyl groups of silica, excellent synergistic properties of silica and the favourable conformation arrangement of organic molecules inside the silica network. The size distribution of synthesised polymeric silica materials have been investigated by dynamic light scattering (DLS) and optical microscopy.

Due to their spectral characteristics, phototoxicity and high affinity for tumour tissues, porphyrins and their derivatives are widely used in modern medicine as contrast agents for cancer diagnostics and as sensitizers in photodynamic therapy, where they kill tumours via enhancement of tumour oxidative stress. The aim of this work was to simulate in vitro the effects caused by oxidation of two free base porphyrins, 5,10,15,20-tetraphenylporphyrin (TPP) and 5,10,15,20-tetra(4-methoxyphenyl)porphyrin (TMOPP). The kinetic study was monitored using spectral techniques and chemiluminescence. The effect of both porphyrins on an oxidation process was evidenced using the chemiluminescent system, luminal-hydrogen peroxide, in a phosphate buffer at pH 7. It was found that at low concentration, TPP exerts the anti-oxidative effect in the employed chemiluminescent system, while at higher concentrations, its effect is pro-oxidative. TMOPP exerts a pro-oxidant effect, which was more pronounced than TPP. The results are discussed with respect to oxidative stress.

Sol–gel chemistry can be easily modified to the changing needs of society to produce fine-tuned sol–gel nanostructured materials for relevant applications. In this context, there is an increasing need for natural and versatile raw materials as well as biocompatible compounds that could be extensively used as biomarkers for bioimaging in diagnosis or therapy. Silica-based materials are widely used in the field of biomedicine due to their chemical inertness and biocompatibility. In the present paper, orange peel extract was immobilized inside inorganic silica and hybrid silica-silsesquioxane polymeric networks. Silica and organo-modified silica matrices were synthesized through a templated sol–gel route of TEOS and an organosilsesquioxane (octaisobutyltetracyclo[7.3.3.15,11] octasiloxane-endo-3,7-diol), with D-glucose as template, and for comparison a non-ionic surfactant (tetraethylene glycol mono-hexadecyl ether) was also used. The bioactive properties of the molecules from orange peel extract were preserved after immobilization in both silica and silica-silsesquioxane networks. Moreover, the fluorescence properties were amplified by 10–20 times more than the native orange peel extract. The structural properties of the final materials have been studied by FT-IR, UV–Vis-NIR, and fluorescence spectroscopy. Dynamic light scattering measurements and transmission electron microscopy were used to estimate the size and morphology of the hybrid materials with orange peel extract immobilized in silica networks. Copyright © 2009 John Wiley & Sons, Ltd.

The environmental impact on human health is of increasing concern mainly due to the complex interaction between various hazardous factors both on environment and within human organism. The aim of this paper is to investigate possible correlations between the quality parameters of drinking water and the formation of uroliths. The constituents of some kidney calculi sampled after surgery from 90 patients coming from the Horezu – Valcea area have been analysed, this region being identified as having the most cases of kidney lithiasis and that might be related with hard drinking waters. The study has been made during the period of 2004 – 2008. Physical – chemical methods specific for characterization of the quality of drinking waters have been used in parallel with determination of composition and structural characterization by X-ray diffraction, thermal analysis TG, ATD, FT-IR spectroscopy, optical microscopy. Four groups of uroliths have been identified: multiphase oxalate and urate, phosphate (hydroxiapatite) and carbonate, monohydrated oxalate (whewellite), and urate stones. Such research might be useful, from both chemical and biochemical point of view, for identifying the conditions that cause the inhibition of the processes related to kidney calculi formation.

The aim of paper is focused on development of novel alternative solutions in order to realise a combination of sensitive molecules with rigid support materials. In this context, a new class of silica precursors based on bridge bonded silsesquioxane organised into periodic mesoporous architecture is suitable for this purpose. A silsesquioxane incompletely condensed (dimethylvinylsilyloxy)-heptacyclo-pentyltricycloheptasiloxanediol) has been selected for sol–gel bioentrapment of retinyl palmitate, in an approach based on high biocompatibility and mild sol–gel encapsulation conditions which enables the reproducible and efficient confinement of retinyl palmitate inside silica. For entrapping of retinyl palmitate within cage structure a templating agent was used, n-dodecyl-β-D-maltoside. The process used for retinyl palmitate encapsulation in silsesquioxane matrix consisted in two main steps: the first step was the synthesis of glucosidal template silica materials, and the second was the encapsulation ...

Synthesis of some novel fluorescence nanomaterials loaded with photoactive polyphenols originated from plants with a high spectrum of biological activity, by replacing synthetic chemicals, may open new opportunities for optical and bio-medical applications. This paper presents the synthesis, characterization and fluorescence properties of a new class of materials based on host hybrid matrices obtained through templated sol–gel route, by hydrolysis and co-condensation of tetraorthoethylsilicate with octaisobutyltetracyclo [7.3.3.15,11] octasiloxane-endo-3,7-diol. The aim of paper is focused on the evaluation of the behavior of the fluorescence properties of ornamental bush extract at immobilization in a templated silica matrix and in a silica-silsesquioxane network, using as templates a neutral, non-toxic and biodegradable surfactant from poly(ethyleneglycol) class and a high biocompatible non-surfactant from glucidic class. The proofs of ornamental bush extract entrapment by physical interactions in silica based networks were provided by FT-IR and UV–VIS spectroscopy. The changes of polymer network due to the hydrogen bond interactions between residual Si–OH groups and functional groups of organic molecules from extract were evidenced by shifts of specific vibrations. In UV–VIS-NIR domain, the chromophore groups from ornamental bush extract were also evidenced by similar small shifts. As a result of ornamental bush extract entrapment, in all the immobilized samples the fluorescence intensity was more than 10 times amplified in samples templated with poly(ethylenglycol) surfactant) and of about 5 times in samples with glucidic template due to the physical adsorption of polyphenolic molecules from extract, excellent synergistic optical properties of SiO2 and silsesquioxane compound and also due to a favorable conformational arrangement. The size of synthesized polymeric materials, estimated by dynamic light scattering technique showed main diameters less then 1.4 μm, namely 1,060 and 211 nm—for samples with d-glucose template and 1,330 and 531 nm—for samples with poly(ethyleneglycol) template, respectively, with a narrow size distribution and a polidispersity varying between 0.022 and 0.426. These results are in good accordance with TEM images that evidenced the presence of some polymeric aggregates which contain the vegetal extract immobilized inside hybrid SiO2-Sq polymeric network of about hundred nanometers size. This study bring new contributions to the development of the sol–gel procedure by entrapment of a complex vegetable mixture in polymeric matrices as integral component of silica and hybrid silica-silsesquioxane networks which leads to a significant enhancement of the functional properties of the final material, thus diversifying the potential applications of organic doped sol–gel glasses.

Mixing elements at nanoscale range can offer exciting possibilities of novel materials with composition, structure and properties quite different from those in the bulk. Fe2O3 nanoparticles embedded in a surrounding silica shell were prepared via surfactant – assisted process by using dodecyl-4-lauryl ether (Brij 30) as oriented template, followed by thermal treatment. The nanoparticles are formed by the precipitation reaction of ferrous and ferric salts with ammonium hydroxide into water-in-oil microemulsion. The hydrodynamic radius of microemulsion droplets and coated nanoparticles were measured by dynamic light scattering. Their structural properties have been studied by FT-IR spectroscopy, thermogravimetric analysis and atomic force microscopy.

The effect of Antipyrin upon the antioxidant activity of the riboflavin has been evidenced using chemiluminescent system luminol-hydrogen peroxide, in Tris-HCl buffer, pH 8.5. It was found that riboflavin antioxidant activity depends on the reaction time and the Antipyrin concentration. Using ESR spectroscopy the hydroxyl radical generation, in the mentioned chemiluminescent system, was evidenced. The interaction between reactants was also investigated by UV-VIS and fluorescence spectroscopy. The effect of Antipyrin concentration upon the riboflavin fluorescence has also been investigated. The fluorescence quenching by Antipyrin is not significant and subsequently the riboflavin fluorescence quenching doesn't indicate an electron transfer process through diffusion-controlled mechanism. The results are discussed with relevance to the redox processes of riboflavin.

A comparative study of the in situ interactions between different maleic anhydride based copolymers and calcium phosphates is presented in this paper. The ability of functional groups of the organic polymers to form under high pressure and low temperatures chemical bonds with the inorganic phase leading to improved properties of hybrid nanostructured material is discussed. The open challenges of new hybrid nanocomposites in the field of biomedical materials are evaluated. The challenge to use these nanostructured materials in medical field was evaluated by mapping the interface reactions between hybrid active layers and cells.

New complexes of Cu(II) with some substituted 2-(3,5-dimethyl-pyrazol-1-yl)-methyl-acetanilides (L) hae been synthesized. The complex compounds, CuL4X2 (where X- = Cl,Br, CH3COO) were characterized by elemental analysis, as well as IR, UV-VIS, EPR spectroscopy. The study evidenced the influence of the position of the methyl group on the benzene ring and also of the anions on the physical properties of the compounds.

In this study the conventional oils used for lipid nanocarriers (NLCs) synthesis were replaced by high concentration of fish oils (e.g., fish oil concentrated in omega-3 fatty acids, fish oil enriched in omega-3 and omega-6 fatty acids and salmon oil), in order to produce appropriate lipid based nanosystems able to entrap willow bark extract (WBE). Formulation factors such as the nature of the fish oil, glycerol content and WBE loading were evaluated to produce optimum lipid based nanosystems with suitable physical stability and enhanced antioxidant activity. The synthesized WBE-NLC showed spherical and homogeneous particles and average diameters in the range of 200-250 nm, as determined by TEM measurements. The electrokinetic potentials were negative for all free- and WBE-loaded NLCs, with values between -29.1 ÷ - 35.8 mV, which reveal an excellent physical stability. By scanning calorimetry measurements it has been shown that the lipid crystallization and melting behavior of NLCs before and after loading with WBE were no significantly influenced by the type of fish oil used and only in a few NLCs formulations an obvious perturbation of lipid network have been detected. The chemiluminescence technique has been used to assess the effect of fish oil type on the in vitro antioxidant activity of WBE-NLCs. Ability of WBE entrapped within NLCs to scavange the free radicals was greater than for native WBE and fish oils. The difference between the antioxidant activity of WBE-NLC (98%) and those of pure WBE (AA% = 77.2) and fish oil (AA% = 83.7), may be explained by the occurrence of a synergistic effect between the components of lipid nanocarriers.

Since their discovery, fullerenes in general and buckminsterfullerene C60 in particular, became a subject of great interest for studies. Being compatible with the sol–gel process, one of the promising approaches is to incorporate the fullerene molecules in sol–gel oxide matrices. Great part of studies deals with SiO2 sol–gel oxide as the optimal matrix for entrapment of organic molecules. C60-doped silica matrices used through our present study have been prepared by sol–gel processing, using different alkoxide precursors, as a silicon oxide source: tetraethoxysilane (a), methyltriethoxysilane (b), phenyltriethoxysilane (c) and a mixture of phenyltriethoxysilane and tetraethoxysilane (d). C60-to-Si molar ratio was chosen to be 1.0 × 10−3:1 for all materials synthesized, final oxide composition remaining unchanged in all cases. The effect of ultrasounds on the gelation process was established by preparing two series of samples, either via sonication or in the absence of ultrasound processing. The properties of the resulted materials were also established. The prepared samples were characterized by XRD, IR, RPE and UV-VIS spectrometry. All methods have put in evidence the embedment of the fullerene into the silica matrix.

New elastomers with high content of 3,4 isoprene units have been developed during the last decades in an attempt to ensure superior performances of the final products and the present study is devoted to the investigation of some peculiarities of their ageing behaviour. On thermo-oxidative degradation, 3,4 isoprene units are less affected in comparison to cis -1, 4 and trans -1, 4 isoprene units. The degradation process consists mainly in splitting of the main chains at temperatures of 80–100 °C while at higher temperatures (120–130 °C) branching becomes a significant modification and this reaction is enhanced for the polymers containing preponderantly 3,4 units. Such behaviour leads to the fact that the processability of polymers containing high amounts of 1,2 and 1,3 isoprene units is less affected by thermo-oxidative degradation in comparison with cis -1, 4-polyisoprene, which could be explained by the fact that large amounts of double bonds are not present in the backbone of macromolecules but in the pendent groups.

New nanocomposite adsorbent based on silica and iron(III) oxide, thermally treated at 200°C has been used for the arsenic(V) removal. Adsorbents were prepared by sol–gel method, the iron oxides being generated in situ during the sol–gel process. Nanocomposite materials thus obtained have a convenient porosity and nanosized iron oxide content. The sorption experiments have been carried out in a batch mode by using aqueous solutions containing 1000 ppm As. The influence of different experimental parameters on the adsorption capacity was investigated. The effect of magnetic field on the enhancement of adsorption process was also revealed.

The new sulfide bridged-polynuclear complexes Cu2(VO)4- (C2O4)4S2L4ċnH2O, where for L=1, 10-phenanthroline, n=5 and for L=2, l0-bipyridine, n=7, have been synthesized and characterized by elemental and thermal analyses, electronic and IR spectroscopy. These data as well as magnetic moments and EPR spectra strongly support a structure in which four [VO(L)(C2O4)(H2O)] units act as ligands toward the two copper(II) centers through the oxalate anion. Each of the oxalate anions act as a tridentate ligand and the core of the complexes involve a copper-sulfide-copper moiety.

Luminol solution in DMSO in the presence of [18C6…K]+ O2 − supramolecular complex (achieved from KO2 and 18-Crown-6 (18C6)-ether) is chemiluminescent, and its intensity depends on the complex concentration. Using fluorescein (Fl) as an energy acceptor in this system, the luminescence energy transfer process from chemically excited species, aminophtalate dianion, to Fl could be evidenced. On the basis of Forster theory, the critical energy transfer distance, for both fluorescence and chemiluminescence, has been determined. The values are comparable: 22.41 A (for chemiluminescence) and 20.88 A (for fluorescence).

Composite iron oxide–SiO2 materials were prepared by a sol–gel method starting with two types of precursors, tetraethoxysilane (TEOS) and methyltriethoxysilane (MTEOS), as the SiO2 source. As the iron source a soluble Fe2+ salt, mainly Fe(SO4)2·7H2O, was used, the iron oxides were generated during the sol–gel process. The amorphous gels obtained were thermally treated up to 1000 °C in order to obtain iron oxides with different structures and grain size. The initial gels and the thermally treated samples were characterised by DTA/TGA analysis, DR-UV–VIS and IR-spectroscopy, EPR measurements, transmission electron microscopy (TEM) and BET surface area methods. The matrices obtained from the precursors play a major role in the evolution of the process. In both cases the initial gels are amorphous. In the non-porous matrix obtained by thermal treatment using methyltriethoxysilane (MTEOS), the tendency for crystallisation increases, and the iron oxide particle size is increased.

Basal cell carcinoma (BCC) is one of the commonest malignancies occurred on sun-exposed skin, mainly by UV-B radiation, of lighter-skinned individuals. The aim of the present study was to develop advanced drug delivery formulations used in BCC therapy that overcomes chemotherapy-induced side-effects of skin photosensitivity by an integrative approach of nanoencapsulation in conjunction with combination therapy that uses chemotherapeutic, chemoprotective and sunscreen agents. The combination of anticancer drug together with sunscreen agent is very useful in therapy, especially for individuals who are more exposed to the sun without using a sunscreen. Nanostructured lipid carriers (NLCs) employed as drug delivery systems were co-loaded with 5-fluorouracil (5-FU), a hydrophilic chemotherapeutic drug, and ethylhexyl salicylate (EHS), a lipophilic UV-B sunscreen agent. The NLCs were developed using bioactive squalene (50.8% w/w) from amaranth seed oil as chemoprotective agent. By varying the concentrations of 5-FU and EHS, the co-loaded NLCs presented particle sizes of about 100 nm, acceptable physical stability with values smaller than −25 mV and appropriate entrapment efficiency that reaches values over 65% for both types of drugs. The UV-B blocking ability of EHS loaded into NLCs were influenced by the concentration of 5-FU. The amaranth oil offered a capacity of 70% in scavenging the free radicals. In vitro drug release showed that NLCs presented sustained release of 5-FU that followed the Fick’s law of diffusion.

Metal complexes ML2Cl2, where M is Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) and L is Schiff base formed by condensation of 2-thiophenecarboxaldehyde and 2-aminopyridine, N-[2-thienylmethylidene]-2-arninopyridine (TNAPY), have been prepared and characterized by elemental analysis, magnetic and spectroscopic measurements. IR and NMR spectra show that the nitrogen of the azomethyne group and the sulphur of the thiophene ring take part in coordination. Magnetic, ESR and electronic spectral studies show a distorted octahedral structure for the Fe(II), Co(II), Ni(II) and Cu(II) complexes and a tetrahedral geometry for the Zn(II) and Cd(II) complexes. Conductance measurements suggest the non-electrolytic nature of the complexes, with the exception of the Zn(TNAPY)2Cl2 and Cd(TNAPY)2Cl2 compounds which are 1:2 electrolytes.

A number of substances with a triazinic structure provide antioxidant properties, but they have been less studied and used in elastomer processing. The presence of thiol groups also allowed the grafting of the triazinic antioxidant on the chain of the unsaturated elastomer during processing, vulcanization and/or the oxidative process. We have evaluated the protective capacity of some substituted triazines both in elastomer matrix and in vulcanizates. Two kinds of triazines, with aminophenolic and phosphonic substituents, have been evaluated for their protective action in diene elastomers as such and in simplified recipe with NR matrix. In elastomers, the triazinic component with one phosphonic group has a superior protective capacity to that of triazine substituted with two phosphonic groups.

Composite SiO2—iron oxide materials were prepared by three experimental procedures. In the first case, the iron oxides were precipitated during a sol-gel process. In the second case, a SiO2 matrix was initially obtained, and the iron oxides were formed by thermal treatment after impregnation of a soluble Fe2+ salt in the previously processed matrix. In the third method, ferrite powders, prepared by wet chemical method, were embedded into a SiO2 based sol-gel matrix. Materials with convenient porosity and nano-sized iron oxide content could be prepared using the mentioned methods. The prepared composite has been tested for arsenic(V) removal.

Composite SiO2-iron oxide materials were prepared by three experimental procedures. In the first case (1), the iron oxides were precipitated during the sol-gel process. In the second case (2), the SiO2 matrix was initially obtained, and the iron oxides were formed by thermal treatment after impregnation of a soluble Fe2+ salt in the previously processed matrix. In the third method (3), ferrite powders, prepared by wet chemical method, were embedded into a SiO2 based sol-gel matrix. Two type of precursors (tetraethoxysilane (TEOS) or methyltriethoxysilane (MTEOS) were used as SiO2 sources. Various properties versus both type of precursor and on the method of preparation were noticed. Materials with high porosity and nano-sized iron oxide content could be prepared using the mentioned above methods.