Traian Costea

Natural Polymeric Beads for Encapsulation of Stellaria media Extract with Antioxidant Properties

Materiale Plastice, 2019

Natural polymers are biodegradable and biocompatible and can be used as carriers of pharmaceutica... more Natural polymers are biodegradable and biocompatible and can be used as carriers of pharmaceutical active compounds, with good results for the enhancement of their stability characteristics.Plant extracts of the Cariophyllaceae family are of great interest due to antioxidant, anti-inflammatory, carminative, anticancer, antibacterial, antifungal, antiviral properties, and more recently, the ability to inhibit intestinal carboxylation and reduce obesity by complex mechanisms.The aim of our study was tocharacterize the Stellaria media aqueous extract from the point of view of total polyphenols (using Folin-Ciocalteu method) and antioxidant capacity, as well as the efficiency of inclusion of Stellaria extract in calcium chloride alginate beads by two different methods. In the same time, the size of alginate microcapsules was investigated along with the released efficiencyfrom the polymeric matrix in different biological fluids.Two different methods for encapsulation of Stellaria media e...

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Growth, Photosynthetic Pigments, Phenolic, Glucosinolates Content and Antioxidant Capacity of Broccoli Sprouts in Response to Nanoselenium Particles Supply

Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 2019

Improving the nutritional quality of plants has emerged from the fact that macro- and micro- nutr... more Improving the nutritional quality of plants has emerged from the fact that macro- and micro- nutrients are limited in various agricultural areas. The aim of our study was the biofortification of broccoli sprouts with selenium nanoparticles (NSePs) and evaluation of growth parameters, assimilator pigments content, total phenols, glucosinolates content along with antioxidant capacity, in order to boost value added output, such as improved nutrition and food functionality. NSePs were prepared by reduction of NaHSeO3 using glucose as reducing agent, and characterized from structural and morphological point of view. The growth of broccoli seedlings was dependent on NSePs concentration. The treatment with 10 and 50 ppm NSePs caused a slight increase in total biomass, by contrast with 100 ppm treatment. Chlorophyll content, total carotenoid and total phenols content was not affected by the treatment of broccoli sprouts with different concentrations of NSePs. Instead, the content of individ...

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A gold nanoparticles - Graphene based electrochemical sensor for sensitive determination of nitrazepam

Journal of Electroanalytical Chemistry, 2018

Abstract A new nanoplatform based on reduced graphene oxide decorated with electrochemically gene... more Abstract A new nanoplatform based on reduced graphene oxide decorated with electrochemically generated gold nanoparticles was developed for sensitive and selective determination of nitrazepam. This nanostructure was characterized by Fourier transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and electrochemical methods. The synergic effect of the two nanomaterials gives an electrode platform with a high surface area, good conductivity and excellent catalytic properties. The sensor exhibited a wide linear range (0.5 μM–400 μM), low limit of detection (0.166 μM), excellent sensitivity, good selectivity, and high stability for nitrazepam determination in serum and a pharmaceutical formulation with excellent recovery rates (99%–102.4%).

Aspects Regarding the Applications of the Nanoindenter in the Characterization of Advanced Materials

The development of new materials is a research area with major implications in all fields, starti... more The development of new materials is a research area with major implications in all fields, starting with the industry up to medical sciences. The ability to use these new materials in areas where their impact will be significant is largely dependent on the ability to precisely determine their characteristics in order to identify those characteristics that are either unique or has a better value. The paper aims to present the applications of the nanoindenter in identifying mechanical characteristics of materials with an example of characterization for an alloy used in the medical field.

Encapsulation of Stellaria Media Extract in Alginate Beads by Using a Novel Method for Controlled Release

Natural Resources and Sustainable Development, 2020

Green Biosynthesis of Selenium Nanoparticles Using Parsley ( Petroselinum Crispum ) Leaves Extract

Selenium (Se) is an essential trace mineral with various biological effects. Different physicoche... more Selenium (Se) is an essential trace mineral with various biological effects. Different physicochemical and biological methods have been reported in literature for selenium nanoparticles (SeNPs) synthesis. The aim of this study was to use the parsley (Petroselinum crispum) leaves extract in order to prepare SeNPs by an eco-friendly method. SeNPs were characterized from structural and morphological point of view by using analytical techniques such as: dynamic light scattering (DLS), UV-Vis spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscopy (AFM). DLS method revealed particles with maximum distribution being registered around 400 nm and an apparent zeta potential value of 14.2 mV. On the other hand, the parsley leaves extract was characterized concerning the total phenols content, vitamin C and antioxidant capacity, in order to evidence potential properties as biocatalyst or natural stabilizers for SeNPs synthesis. This study reports for the first ...

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Impact of Metallic Nanoparticles on Assimilatory Pigment and Proline Accumulation in Leaves of Hordeum Vulgare L

Analysis of Contact Resistance Variation in Electric Devices Under Electric Charge

The paper presents a study regarding electric contacts conductivity, from the structure of certai... more The paper presents a study regarding electric contacts conductivity, from the structure of certain types of electric devices, during their functioning under electric charge. The variation of the contact resistance, according to the structural changes of the contact surface is taken into study. The structure of the contacts surface was analyzed by microscopy.

Novel Hybrid Composites Based on PVA/SeTiO2 Nanoparticles and Natural Hydroxyapatite for Orthopedic Applications: Correlations between Structural, Morphological and Biocompatibility Properties

Materials

The properties of poly(vinyl alcohol) (PVA)-based composites recommend this material as a good ca... more The properties of poly(vinyl alcohol) (PVA)-based composites recommend this material as a good candidate for the replacement of damaged cartilage, subchondral bone, meniscus, humeral joint and other orthopedic applications. The manufacturing process can be manipulated to generate the desired biomechanical properties. However, the main shortcomings of PVA hydrogels are related to poor strength and bioactivity. To overcome this situation, reinforcing elements are added to the PVA matrix. The aim of our work was to develop and characterize a novel composition based on PVA reinforced with Se-doped TiO2 nanoparticles and natural hydroxyapatite (HA), for possible orthopedic applications. The PVA/Se-doped TiO2 composites with and without HA were structurally investigated by FTIR and XRD, in order to confirm the incorporation of the inorganic phase in the polymeric structure, and by SEM and XRF, to evidence the ultrastructural details and dispersion of nanoparticles in the PVA matrix. Both ...

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Metal Nanoparticles and Carbon-Based Nanomaterials for Improved Performances of Electrochemical (Bio)Sensors with Biomedical Applications

Materials

Monitoring human health for early detection of disease conditions or health disorders is of major... more Monitoring human health for early detection of disease conditions or health disorders is of major clinical importance for maintaining a healthy life. Sensors are small devices employed for qualitative and quantitative determination of various analytes by monitoring their properties using a certain transduction method. A “real-time” biosensor includes a biological recognition receptor (such as an antibody, enzyme, nucleic acid or whole cell) and a transducer to convert the biological binding event to a detectable signal, which is read out indicating both the presence and concentration of the analyte molecule. A wide range of specific analytes with biomedical significance at ultralow concentration can be sensitively detected. In nano(bio)sensors, nanoparticles (NPs) are incorporated into the (bio)sensor design by attachment to the suitably modified platforms. For this purpose, metal nanoparticles have many advantageous properties making them useful in the transducer component of the (...

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Natural Polymeric Beads for Encapsulation of Stellaria media Extract with Antioxidant Properties

Materiale Plastice

Natural polymers are biodegradable and biocompatible and can be used as carriers of pharmaceutica... more Natural polymers are biodegradable and biocompatible and can be used as carriers of pharmaceutical active compounds, with good results for the enhancement of their stability characteristics.Plant extracts of the Cariophyllaceae family are of great interest due to antioxidant, anti-inflammatory, carminative, anticancer, antibacterial, antifungal, antiviral properties, and more recently, the ability to inhibit intestinal carboxylation and reduce obesity by complex mechanisms.The aim of our study was tocharacterize the Stellaria media aqueous extract from the point of view of total polyphenols (using Folin-Ciocalteu method) and antioxidant capacity, as well as the efficiency of inclusion of Stellaria extract in calcium chloride alginate beads by two different methods. In the same time, the size of alginate microcapsules was investigated along with the released efficiencyfrom the polymeric matrix in different biological fluids.Two different methods for encapsulation of Stellaria media e...

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Nano-Scale Modifications of Amniotic Membrane Induced by UV and Antibiotic Treatment: Histological, AFM and FTIR Spectroscopy Evidence

Materials

The efficiency of amniotic membrane (AM) transplantation in different types of ocular surface dis... more The efficiency of amniotic membrane (AM) transplantation in different types of ocular surface disorders is due to its outstanding properties such as antifibrotic, antibacterial, anti-inflammatory and antiangiogenic, working as a versatile scaffold to promote corneal tissue epithelialization. A proper preparation, preservation and clinical application are crucial for the best outcomes in the treatment of different severe ocular disorders, taking into account its fragility. In this context, by combining high-sensitivity tools such as atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy with histological and immunohistochemical examination, we aimed to investigate the ultrastructural modifications of the amniotic membrane (AM) upon UV exposure and/or antibiotic treatment, with relevance for clinical applications in ocular surface surgery. From the morphological point of view, we noticed a loss of cuboidal cells in the basal membrane, accompanied by the split...

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A gold nanoparticles - Graphene based electrochemical sensor for sensitive determination of nitrazepam

Journal of Electroanalytical Chemistry

Growth, Photosynthetic Pigments, Phenolic, Glucosinolates Content and Antioxidant Capacity of Broccoli Sprouts in Response to Nanoselenium Particles Supply

Notulae Botanicae Horti Agrobotanici Cluj-Napoca

Improving the nutritional quality of plants has emerged from the fact that macro- and micro- nutr... more Improving the nutritional quality of plants has emerged from the fact that macro- and micro- nutrients are limited in various agricultural areas. The aim of our study was the biofortification of broccoli sprouts with selenium nanoparticles (NSePs) and evaluation of growth parameters, assimilator pigments content, total phenols, glucosinolates content along with antioxidant capacity, in order to boost value added output, such as improved nutrition and food functionality. NSePs were prepared by reduction of NaHSeO3 using glucose as reducing agent, and characterized from structural and morphological point of view. The growth of broccoli seedlings was dependent on NSePs concentration. The treatment with 10 and 50 ppm NSePs caused a slight increase in total biomass, by contrast with 100 ppm treatment. Chlorophyll content, total carotenoid and total phenols content was not affected by the treatment of broccoli sprouts with different concentrations of NSePs. Instead, the content of individ...

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Eco-friendly, Facile and Rapid Way for Synthesis of Selenium Nanoparticles Production, structural and morphological characterisation

Revista de Chimie, Jan 15, 2018

A green chemistry approach to synthesize biocompatible selenium nanoparticles is proposed in this... more A green chemistry approach to synthesize biocompatible selenium nanoparticles is proposed in this work, using hydrogen selenite (NaHSeO 3) as selenium precursor and lactose as reducing agent. The formation of nanoparticles was confirmed by dynamic light Scattering, revealing a gaussian size distribution, the maximum percentage being in the range of 20-40 nm. Zeta potential measurement indicates a negative charge-38.2 mV, the stability of selenium colloidal sol being also confirmed by UV-visible spectroscopy. TEM and AFM revealed the homogeneous, spherical shape, confirming the size of nanoparticles in the range of 20-40 nm. Structural investigations of powder selenium nanoparticles by FTIR spectroscopy and XRD patterns emphasise the presence of stretching and bending vibrations of Se-O bonds, respectively the amorphous structure of the synthesized selenium. The proposed method is suitable for biological applications such drug release, functional food or nutritional supplements.

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Shiba states coupled to a resonant cavity

When a quantum dot is embedded into a superconducting environment, it leads to the formations of ... more When a quantum dot is embedded into a superconducting environment, it leads to the formations of localized Shiba states inside the gap. If the Coulomb interaction is sufficiently small, the Shiba states consist of a pair of singlet states and a doublet, that compete for the ground state and induce a quantum phase transition. In the presence of an external microwave field, the Shiba energy spectrum is significantly modified. Moreover, the transmission of the cavity inherits features that can pinpoint the exact location of the quantum critical point. In terms of methods used, our analytical calculations are supplemented by state of the art numerical renormalization group calculations.

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Mechanical Characterization of Advanced Ceramic Materials Using Nanoindentation

The paper aims to present the result obtained during mechanical characterization of ceramic mater... more

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Novel Formulation Based on Chitosan-Arabic Gum Nanoparticles Entrapping Propolis Extract Production, physico-chemical and structural characterization

Revista de Chimie

The aim of our study was to prepare and characterize chitosan-based nanoparticles encapsulating p... more The aim of our study was to prepare and characterize chitosan-based nanoparticles encapsulating propolis extract by ionotropic gelation and glutaraldehyde cross-linking technique. Both spectroscopic (UV-Vis, FTIR) and microscopic techniques (AFM) were applied for structural characterization of nanoparticles, along with entrapment and release study of propolis extract. The physico-chemical properties and morphological features of the obtained nanoparticles demonstrated a good correlation between all the investigated methods. Moreover, the bioactive compounds were stable upon the encapsulation procedure. Propolis release from the polymeric matrix was monitored in both simulated gastric acid and simulated intestinal fluids, concluding that our proposed formulation is suitable for controlled release. These results may provide a novel design, with improved bioavailability, stability and nutritional value of propolis bioactive compounds during processing and storage, with possible applica...

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Study on the Influence of the Grind Percentage Over the Surface Hardness and Modulus of Elasticity of Parts Made of ABS, P6.6 and POM through Nanoindentation

Materiale Plastice

This paper analyzes the indentation hardness and the indentation elastic modulus variation depend... more This paper analyzes the indentation hardness and the indentation elastic modulus variation depending on the variation of the grind percentage of polymer, when the other factors that can influence the injection molding remain unchanged. The analyzed polymers were: acrylonitrile butadiene styrene ABS MAGNUM 3453, polyamide PA 6.6 TECHNYL AR218V30 Blak and polyoxymethylene POM EUROTAL C9 NAT. The samples that were studied had different compositions in new and grinding material. The G-Series Basic Hardness Modulus at a Depth method was used. The increase of the grind percentage of ABS (from 0 to 100 %) leads to insignificant changes in the indentation hardness, indentation modulus, and maximum force applied to samples of tested material. The maximum hardness (0.137 GPa) of PA 6.6 is recorded in the case of the sample with 80% grind content, and the maximum hardness of POM is recorded as well in the case of the sample with 80% grind content, as being 0.215 GPa. The variation of the grind...

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Determining the Influence of the Processing Temperature by Injection and of the Subsequent Pressure on the Surface�s Hardness and Indentation Modulus of the Products Made of HDPE, PMMA, PC+ABS through Nanoindentation - G-Series Basic Hardness Modulus at a Depth Method

Materiale Plastice

The first part of the paper presents the influence of the processing temperature by injection of ... more The first part of the paper presents the influence of the processing temperature by injection of HDPE, of PMMA, and PC+ABS blend on the indentation hardness and on the indentation modulus, when other factors that can influence the injection remain unchanged. The second part of the paper presents the influence of subsequent pressure by injection of HDPE, PMMA, and PC+ABS blend on the indentation hardness and on the indentation modulus, when the other factors remain unchanged. The HDPE samples were obtained at the following injection temperatures: 180, 190, 200, 210, and 220�C, and at the following subsequent pressures: 800 bar, 900 bar, 1000 bar, 1100 bar, and 1200 bar. The PMMA samples were obtained at the following injection temperatures: 220, 230, 240, 250, and 260�C, and at the following subsequent pressures: 450, 550, 650 , 750, and 850 bar. The PC+ABS samples were obtained at the following injection temperatures: 230, 240, 250, 260, and 270�C, and at the following subsequent pr...

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