Structural, Morphological, and Antibacterial Attributes of Graphene Oxide Prepared by Hummers' and Brodie's Methods.

Graphite oxidation to graphene oxide (GO) is carried out using methods developed by Brodie (GO-B) and Hummers (GO-H). However, a comparison of the antibacterial properties based on the physicochemical properties has not been performed. Therefore, this paper outlines a comparative analysis of GO-H and GO-B on antibacterial efficacy against Gram-positive and Gram-negative bacterial cultures and biofilms in an aqueous environment and discusses which of the properties of these GO nanomaterials have the most significant impact on the antibacterial activity of these materials.

Functional Mechanical Behavior and Biocompatible Characteristics of Graphene-Coated Cardiovascular Stents.

Percutaneous Coronary Intervention (PCI) is a treatment method that involves reopening narrowed arteries with a balloon catheter that delivers a cylindrical, mesh-shaped implant device to the site of the stenosis. Currently, by applying a coating to a bare metal stent (BMS) surface to improve biocompatibility, the main risks after PCI, such as restenosis and thrombosis, are reduced while maintaining the basic requirements for the mechanical behavior of the stent itself. In this work, for the first time, the development and optimization process of the spatial structure of the Co-Cr stent (L-605) with a graphene-based coating using cold-wall chemical vapor deposition (CW-CVD) to ensure uniform coverage of the implant was attempted.

Composite Nanostructures for the Production of White Light.

In this work, two different composite nanostructures, YAG:Ce and GaInN, were prepared by the Urea Glass Route method and tested for the production of white light. The first composite was prepared by synthetizing the GaInN nanoparticles in the presence of YAG:Ce nanoparticles. The second one was prepared by synthetizing YAG:Ce nanoparticles in the presence of GaInN nanoparticles.

Urea Glass Route as a Way to Optimize YAGG:Ce,Cr,Pr Nanocrystals for Persistent Luminescence Applications.

A new approach for the synthesis of YAlGaO (YAGG) nanophosphors allowing the preparation of crystallites with sizes starting from 45 nm is presented. The controllability of the energy and trap density of the resulting material samples by annealing temperature was confirmed by thermoluminescence (TL) measurements. It has been shown that the annealing of samples at temperatures up to 1300 °C does not cause any substantial growth of crystallites, still remaining below 100 nm, but leads to changes in the activation energy of the persistent luminescence (PersL) process.

Size-Dependent Persistent Luminescence of YAGG:Cr Nanophosphors.

In the current work, YAGG:Cr nanophosphors were synthesized by the Pechini method and then annealed at different temperatures in the range 800-1300 °C. The structure and morphology of the samples were characterized by X-ray Powder Diffraction (XRPD). The lattice parameters and average crystalline sizes as site occupation by Al and Ga ions were calculated from the Rietveld refinement data.

Sicilian Byzantine Icons through the Use of Non-Invasive Imaging Techniques and Optical Spectroscopy: The Case of the .

The iconographic heritage is one of the treasures of Byzantine art that have enriched the south of Italy, and Sicily in particular, since the early 16th century. In this work, the investigations of a Sicilian Icon of Greek-Byzantine origin, the , is reported for the first time. The study was carried out using mainly non-invasive imaging techniques (photography in reflectance and grazing visible light, UV fluorescence, infrared reflectography, radiography, and computed tomography) and spectroscopic techniques (X-ray fluorescence and infrared spectroscopy).

Graphene Coating Obtained in a Cold-Wall CVD Process on the Co-Cr Alloy (L-605) for Medical Applications.

Graphene coating on the cobalt-chromium alloy was optimized and successfully carried out by a cold-wall chemical vapor deposition (CW-CVD) method. A uniform layer of graphene for a large area of the Co-Cr alloy (discs of 10 mm diameter) was confirmed by Raman mapping coated area and analyzing specific G and 2D bands; in particular, the intensity ratio and the number of layers were calculated. The effect of the CW-CVD process on the microstructure and the morphology of the Co-Cr surface was investigated by scanning X-ray photoelectron microscope (SPEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS).

Particle size-related limitations of persistent phosphors based on the doped YAlGaO system.

Co-doped Ce, Cr and Pr yttrium-aluminium-gallium garnet powders of various sizes were obtained by co-precipitation method. The microstructure and morphology were investigated by XRPD, TEM and gas porosimetry. The luminescence properties were studied by excitation and emission spectra, quantum yield and decay times.

Gallato Zirconium (IV) Phtalocyanine Complex Conjugated with SiO2 Nanocarrier as a Photoactive Drug for Photodynamic Therapy of Atheromatic Plaque.

A new conjugate of gallato zirconium (IV) phthalocyanine complexes (PcZrGallate) has been obtained from alkilamino-modified SiO nanocarriers (SiO-(CH)-NHNPs), which may potentially be used in photodynamic therapy of atherosclerosis. Its structure and morphology have been investigated. The photochemical properties of the composite material has been characterized.

Graphene Oxide Carboxymethylcellulose Nanocomposite for Dressing Materials.

Sore, infected wounds are a major clinical issue, and there is thus an urgent need for novel biomaterials as multifunctional constituents for dressings. A set of biocomposites was prepared by solvent casting using different concentrations of carboxymethylcellulose (CMC) and exfoliated graphene oxide (-GO) as a filler. -GO was first obtained by the strong oxidation and exfoliation of graphite.

Kinetics of Cr to Cr ion valence transformations and intra-lattice cation exchange of Cr in Cr,Ca:YAG ceramics used as laser gain and passive Q-switching media.

This paper focuses on the kinetics of Cr formation in Cr,Ca:YAG ceramics prepared by solid-state reaction sintering. The kinetics of Cr formation was studied by annealing of Cr,Ca:YAG ceramics in ambient air under different temperatures at different times, resulting in the transformation of Cr to Cr. The activation energy (E) of Cr oxidation determined by the Jander model was 2.

Structural and optical characterization of RbLaPO:Ln (Ln = Ce, Nd, Tm, or Yb).

In this work, for the first time, detailed structural and optical characterization of RbLaPO doped with different concentrations of Ce, Nd, Tm, or Yb ions is reported. The samples were obtained via a precipitation technique. Their structural characterization was performed using X-ray diffraction (XRD), and infrared and Raman spectroscopies.

Non-conventional Ce:YAG nanostructures via urea complexes.

Ce:YAG nanostructures (Ce:YAG = Cerium in Yttrium Aluminium Garnet), easy to control and shape, have been prepared via templating approach using natural and synthetic materials (i.e. paper, cotton wool and glass wool) previously soaked with a gel-like metals precursor and then thermally treated to achieve the wished morphology.

Biocompatible Carbon-Based Coating as Potential Endovascular Material for Stent Surface.

Stainless steel 316L is a material commonly used in cardiovascular medicine. Despite the various methods applied in stent production, the rates of in-stent restenosis and thrombosis remain high. In this study graphene was used to coat the surface of 316L substrate for enhanced bio- and hemocompatibility of the substrate.

Laser induced white emission generated by infrared excitation from Eu:SrCeO nanocrystals.

The laser induced white emission (LIWE) was observed from Eu:SrCeO nanocrystals. The samples were obtained in form of powders by the modified sol-gel route. The structure and morphology of the phosphors were investigated by powder X-ray diffraction and transmission electron microscope techniques.

Laser induced white lighting of graphene foam.

Laser induced white light emission was observed from porous graphene foam irradiated with a focused continuous wave beam of the infrared laser diode. It was found that the intensity of the emission increases exponentially with increasing laser power density, having a saturation level at ca. 1.

Broadband anti-Stokes white emission of SrCeO nanocrystals induced by laser irradiation.

The laser induced white emission (LIWE) from SrCeO nanocrystals upon irradiation with a focused IR laser beam was investigated. It was observed to be a threshold phenomenon with its intensity increasing exponentially with the excitation power density. This process was investigated under double laser beam simultaneous excitation in the UV range leading to Stokes emission in the visible range and in the IR range leading to anti-Stokes LIWE.

Cytotoxic interactions of bare and coated NaGdF4:Yb(3+):Er(3+) nanoparticles with macrophage and fibroblast cells.

The lanthanide nano-compounds are well suited to serve as fluorescent and magnetic contrast agents and luminescent labels. Although they are considered as promising materials for bio-imaging and bio-sensors in vivo or in vitro, the amount of data is still insufficient for deep understanding the toxicity of these nanomaterials. This knowledge is of great importance in the light of growing use of the biofunctionalized nanoparticles, which raises some questions about safety of these materials.

Synthesis and up-conversion luminescence of Er(3+) and Y b(3+) codoped nanocrystalline tetra- (KLaP4O12) and pentaphosphates (LaP5O14).

The up-converting nanocrystals of KLa0.95Er0.05Y bxP4O12 and La0.

Near infrared absorbing near infrared emitting highly-sensitive luminescent nanothermometer based on Nd(3+) to Yb(3+) energy transfer.

A new type of near infrared absorbing near infrared emitting (NANE) luminescent nanothermometer is presented, with a physical background that relies on efficient Nd(3+) to Yb(3+) energy transfer under 808 nm photo-excitation. The emission spectra of LiLa0.9-xNd0.

Influence of grain size on optical properties of Sr2CeO4 nanocrystals.

The absorption, excitation, and emission spectra of the Sr2CeO4 nanocrystals prepared by the modified sol-gel method were investigated. The impact of the average grain size of Sr2CeO4 nanocrystals on their optical properties was investigated. It was observed that with increasing the average grain size of Sr2CeO4 nanocrystals, the emission decay times decreased significantly.

Synthesis and luminescent properties of La(1-x)Nd(x)P₅O₁₄ nanocrystals.

La(1-x)Nd(x)P5O14 nanocrystals were synthesized using a coprecipitation method. Their structure and morphology were determined. The luminescence and excitation spectra of La(1-x)Nd(x)P5O14 nanocrystals were measured in the entire range of Nd(3+) concentration.

Structural and spectroscopic properties of Yb³⁺-doped MgAl₂O₄ nanocrystalline spinel.

Magnesium spinel (MgAl2O4) powders doped with Yb(3+) ions have been synthesized by a sol-gel method and heat-treated in the range of 700-1000 °C for 3 h. XRD patterns indicated that the powders have a cubic structure with high crystallite dispersion. Nanoparticles in the range of 10-30 nm are obtained as a function of the dopant concentration and sintering temperature.

[Use of the materials based on partially reduced graphene-oxide with silver nanoparticle as bacteriostatic and bactericidal agent].

Background: Researches have been synthesizing nanocomposites with antibacterial properties for a dozen of years. A lot of study have confirmed a high antibacterial activity of silver nanoparticles and oxygraphene. Silica, titanium dioxide and hydroxyapatites of 1-100 nm are used as carrier for these composites.