CHARACTERIZATION OF THE GOLD MERCAPTOTRIAZOLE COMPLEX USING THE TANDEM QUADRUPOLE MASS SPECTROMETRY (TQD)

This work is aimed to characterize the gold complexes using the electron spray ionization (ESI), and atmospheric solids analysis probe (ASAP), tandem quadrupole mass spectrometer (TQD). It is demonstrated here that the use of the ASAP is more suitable than the ESI for a rapid analysis of the gold coatings in the solid and liquid state. The mass spectra indicate that mercaptotriazole and glycine can coordinate with the gold ion and to build complexes such as [Au-2MT-Gly] and [Au-2MT-2Gly]

Uticaj usitnjavanja mikrostrukture na svojstva Ti-45Nb legure u fiziološkim uslovima

The high-pressure torsion (HPT) post-processing treatment influence on the grain refinement, corrosion behavior, and biocompatible properties of the Ti-45Nb (mass%) alloy, as a promising new hard-tissue replacement material, was investigated in the present study. The HPT-induced microstructural alterations were experimentally analyzed by electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), x-ray diffraction (XRD), and Vickers microhardness measurements, while additional theoretical investigations on the ab initio level were conducted to fully investigate the HPT influence on the alloy microstructural properties. Results showed that significant microstructural refinement was achieved through the HPT processing while a change in alloy phase composition was not detected. In both, unrefined and refined, microstructures the β-Ti and Ti4Nb phases were identified and confirmed by the ab initio modeling results. The microstructural alterations effect on the alloy corrosion behavior in simulated physiological conditions was examined through the potentiodynamic polarization measurements. In vitro tests were conducted to determine the grain refinement influence on the investigated alloy and live cells interaction. Attained results indicated that the HPT treatment can be successfully applied to improve the Ti-45Nb alloy bio-corrosive performance through an increase of the alloy hardness, corrosion resistance, and live cells viability during the alloy-cells interaction.Tokom prezentovanog istraživanja ispitan je uticaj postupka uvijanja pod visokim pritiskom (UVP) na rafinaciju zrna, koroziono ponašanje i biokompatibilna svojstva Ti-45Nb (mas.%) legure, kao potencijalnog materijala za izradu kostnih implanata. Mikrostrukturne promene, uslovljene primenom UVP postupka, analizirane su elektronskom difrakcijom, transmisionom elektronskom mikroskopijom, difrakcijom x-zraka i određivanjem mikrotvrdoće, dok su teorijska istraživanja na ab initio nivou izvršena u cilju potpunog ispitivanja uticaja UVP metode na mikrostrukturna svojstva legure. Primenom UVP postupka postignuto je značajno usitnjavanje mikrostrukture bez promene faznog sastava legure. U nerafinisanoj i rafinisanoj mikrostrukturi identifikovane su β-Ti i Ti4Nb faze, što su potvrdili i rezultati ab initio modelovanja. Uticaj promene mikrostrukturnih svojstava na korozionu postojanost legure u simuliranim fiziološkim uslovima ispitan je potenciodinamičkom metodom. Uticaj rafinacije zrna na potencijalnu interakciju implantne legure sa živim ćelijama ispitan je primenom in vitro metoda. Potvrđeno je da se UVP obrada može uspešno primeniti za poboljšanje bio-korozionog ponašanja Ti-45Nb legure kroz povećanje tvrdoće i korozione otpornosti legure, kao i vijabilnosti ćelija tokom interakcije legure sa živim ćelijama22nd YuCorr International Conference : Proceedings : September 13-16, 2021 : Tara Mountain, Serbi

MASS SPECTROMETRY FOR STRUCTURAL CHARACTERIZATION OF NON-CYANIDE GOLD COMPLEX

In this work, the possibilities of a mass spectrometry approach towards the characterizations of the electrolyte for decorative gold plating based on mercaptotriazole were studied. All mass spectra were obtained using laser desorption ionization (LDI) method on a commercial matrix assisted laser desorption ionization – time of flight (MALDI-TOF) mass spectrometer. The LDI MS spectra of chloroauric acid gave evidence of the presence of a variety of monomeric and polymeric complexes. LDI MS spectra of the electrolyte obtained from chloroauric acid, glycine and mercaptotriazole revealed existence of the ion at m/z 472 which indicated that the complex [Au(NH2CH2COOH)(C2H2N3S)2]- has been formed

Laserska površinska modifikacija metalnih implantantnih materijala

Metallic biomaterials are most commonly used as hard-tissue replacements because of their favorable mechanical features and excellent biocompatibility. The objective of this paper is to present an overview of diverse surface modification techniques, with a special emphasis on the laser surface modification method, as well as diverse characterization techniques used for investigating the impact of the surface modification process on metallic implant materials' properties. Moreover, the effect of laser radiation on the surface its and mechanical characteristics, as well as on the structure of metallic bioimplants, is presented. The study of influence of high-intensity laser radiation on metallic materials' surface includes primarily investigations of the surface morphology modifications and specific surface structure formation since their presence enables enhanced osseointegration.Metalni biomaterijali se najčešće koriste za izradu implantanata čvrstih strukturnih delova ljudskog tela zbog svojih dobrih mehaničkih karakteristika i odlične biokompatibilnosti. Cilj rada je da se pregledno predstave različite tehnike površinske modifikacije implantantnih materijala sa posebnim osvrtom na metodu laserske modifikacije površine, kao i mnogobrojne karakterizacione metode za ispitivanje uticaja procesa površinske modifikacije na svojstva metalnih implantantnih materijala. Osim toga, predstavljen je i razmatran uticaj laserskog zračenja na površinske i mehaničke karakteristike, kao i na strukturu metalnih bioimplantanata. Ispitivanje uticaja laserskog zračenja visokog intenziteta na površinu metalnih materijala prvenstveno obuhvata ispitivanje morfoloških površinskih promena i formiranja specifičnih površinskih struktura, koje doprinose poboljšanju oseointegracije metalnih implantanata

Laser irradiation as an easy-to-apply method for Ti-based implant materials enhancement

Hard-tissue replacements are most commonly made from the Ti-based materials, such as commercially pure titanium (CP-Ti) and Ti-6Al-4V (mass%) alloy, because of their exceptional biocompatible properties combined with the excellent corrosive and mechanical characteristics [1]. More recently, efforts have been made to additionally enhance the properties of the metallic implants through the careful selection of the alloy composition and surface modification technics [2,3]. As a result, second-generation β-type Ti alloys, containing non-toxic elements, have been developed. One of the promising β-type implant alloys is Ti-13Nb-13Zr (mass%). Even though the corrosion resistance and mechanical properties of this alloy are improved in comparison to the commonly used metallic implant materials, its biocompatible and osseointegration properties can and must be additionally enhanced. For that purpose several surface modification technics can be used, however, laser irradiation stands out as the most promising one. Because of that scope of the present research was to investigate the possibility of successful surface modification of the most commonly used implant material, i.e. CP-Ti, and the second-generation Ti-13Nb-13Zr alloy by utilizing the easy-to-apply laser irradiation method in order to obtain improved implant tribocorrosive properties and enhanced biointegration and bioactivity. Laser surface modifications were conducted using the Nd:YAG system in the air and argon atmosphere under different laser output energies. Implant materials surface morphologies after the laser irradiation treatment were investigated using the field-emission scanning electron microscopy (FE-SEM) and optical profilometry, while the impact of the laser irradiation on the implant materials surface characteristics were examined using the energy dispersive spectrometry (EDS) and microhardness measurements. Conducted research showed that utilization of the Nd:YAG laser irradiation resulted in significant alterations of the CP-Ti and Ti-13Nb-13Zr alloy surface chemistry, morphology and microhardness. Laser irradiation of both investigated materials led to the formation of visible microcracks and hydrodynamic effects in the central part of the irradiated area, while traces of melted and solidified material were observed at its periphery. More pronounced morphological changes were induced during the laser irradiation in an argon atmosphere, while a higher degree of texturing was recorded at the surface of the Ti-13Nb-13Zr alloy. At the irradiated surfaces, the formation of the oxide layer, predominantly composed of Ti-oxide particles, was detected. Surface oxides are desirable since their presence can improve the implant material bioactivity with a simultaneous increase of the tribo-corrosive properties through the formation of the hard corrosion resistance surface film. Laserinduced chemical and morphological alterations were more distinctive in the case of the Ti-13Nb- 13Zr alloy

Surface modifications of biometallic commercially pure Ti and Ti-13Nb-13Zr alloy by picosecond Nd:YAG laser

The effects of picosecond Nd:YAG laser irradiation on chemical and morphological surface characteristics of the commercially pure titanium and Ti-13Nb-13Zr alloy in air and argon atmospheres were studied under different laser output energy values. During the interaction of laser irradiation with the investigated materials, a part of the energy was absorbed on the target surface, influencing surface modifications. Laser beam interaction with the target surface resulted in various morphological alterations, resulting in crater formation and the presence of microcracks and hydrodynamic structures. Moreover, different chemical changes were induced on the target materials' surfaces, resulting in the titanium oxide formation in the irradiation-affected area and consequently increasing the irradiation energy absorption. Given the high energy absorption at the site of interaction, the dimensions of the surface damaged area increased. Consequently, surface roughness increased. The appearance of surface oxides also led to the increased material hardness in the surface-modified area. Observed chemical and morphological changes were pronounced after laser irradiation of the Ti-13Nb-13Zr alloy surface

Impact of Microstructural and Surface Modifications on the Ti-45Nb Alloy’s Response to Bio-Environment

The Ti-45Nb (mass%) alloy’s corrosive and biocompatible response in simulated physiological conditions was investigated before and after its additional high-pressure torsion (HPT) and laser irradiation processing. The grain size reduction from 2.76 μm to ~ 200 nm and the appearance of laser-induced morphologically altered and highly oxidized surface led to the significant improvement of alloy corrosion resistance and cell–implant interaction. Moreover, an additional increase of the laser pulse energy from 5 to 15 mJ during the alloy irradiation in the air led to an increase in the surface oxygen content from 13.64 to 23.89% accompanied by an increase of excellent cell viability from 127.18 to 134.42%. As a result of the controlled alloy microstructural and surface modifications, the formation of protective bi-modal mixed Ti- and Nb-oxide external scale was enabled. The presence of this surface oxide scale enhanced the alloy’s resistance to corrosion deterioration and simultaneously boosted cell viability and proliferation

Ultrafine-grained microstructure effect on the biomedical Ti-based alloy performance

5th International Conference on Structural Nano Composites (NANOSTRUC 2023) : book of abstracts; May 24-26, 2023, Nicosia, Cypru

UDC 537.569/.534.8

Abstract. Content and composition of total and free fatty acids of the air dried leaves of the Serbian selected tobaccos type Prilep, Yaka and Otlja were investigated by GC. In all three tobacco types palmitic acid was the major component: 47.1 % of the total acids and 17.0 % of the free acids for Prilep, 43.9 % of the total acids and 16.0 % of the free acids for Yaka and 34.2 % of the total acids and 5.0 % of the free acids for Otlja tobacco. The U/S values for free and total fatty acids, as well as the content of free fatty acids for the semioriental tobacco Otlja, were almost twice higher than in oriental Yaka and Prilep making them a good marker characteristic distinguishing the two tobacco types. Key words: Nicotiana tabacum, oriental and semioriental tobaccos, fatty acids, G