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1.
Removal of neodymium ions from aqueous solution by magnetic nanoparticles
Ana Ambrož, 2021, magistrsko delo

Opis: This work is focused on the synthesis and characterization of surface-functionalized γ-Fe2O3-NH4OH@SiO2(APTMS) nanoparticles, their applications, and performance for Nd3+ removal from aqueous solutions, with an emphasis on the characterization of MNPs and Nd(NO3)3•6H2O. The γ-Fe2O3 nanoparticles were obtained by the co-precipitation method, stabilized with ammonia solution, and functionalized by SiO2 and APTMS. Neodymium nitrate hexahydrate (Nd(NO3)3•6H2O) used in aqueous solution was synthesised from neodymium oxide (Nd2O3) powder. The thermal behaviour and stability of the magnetic nanoparticles and Nd(NO3)3•6H2O was studied with thermogravimetric analysis (TGA) in O2, N2, and air atmosphere. Transmission electron microscopy (TEM) images were obtained in order to analyse the particle morphology and measure the size distribution of the nanoparticles. The hydrodynamic diameter of particles and the zeta potential were measured to determine the stability of particles in the solution. ATR-FTIR spectroscopy was used to confirm the functionalization of the magnetic nanoparticles and the adsorption of Nd3+ ions. The effect of the REE adsorption on the MNPs was studied by comparing the sample’s UV-Vis absorption spectra. The laboratory testing and analysis of the results indicate promising applications for the removal of the REE from aqueous solutions with magnetic nanoparticles. However, the coating of the MNP core by SiO2(APTMS) is inefficient for the removal of Nd3+ ions.
Ključne besede: Magnetic nanoparticles, Rare earth elements, Neodymium, Adsorption, Zeta potential, UV-Vis spectroscopy
Objavljeno: 03.05.2021; Ogledov: 46; Prenosov: 12
.pdf Celotno besedilo (2,51 MB)

2.
Complementary assessment of commercial photoluminescent pigments printed on cotton fabric
Selestina Gorgieva, Natalija Virant, Alenka Ojstršek, izvirni znanstveni članek

Opis: The presented study focuses on photoluminescent pigments applied on cotton fabric by a screen-printed procedure using polydimethylsiloxane (PDMS) as a binder. Microscopic data depicts irregular shapes and relatively wide size distribution (3–80 µm) of pigments. Regarding composition,the Energy-Dispersive X-ray (EDX) and Fourier Transform Infrared (FTIR) spectroscopy data complement findings suggesting the presence of Eu-doped strontium aluminate in the yellow-green,calcium aluminate in the violet pigment, and metal oxides in the blue pigment.
Ključne besede: photoluminescent pigments, cotton fabric, screen-printing, photoluminescent PDMS coating, confocal microscopy, spectroscopy, printed cotton fabrics, pigments
Objavljeno: 08.04.2021; Ogledov: 48; Prenosov: 7
.pdf Datoteka (10,19 MB)

3.
Electrochemical and surface analysis of 2-phenylimidazole adsorbed on copper from chloride solution
Matjaž Finšgar, Klodian Xhanari, 2018, izvirni znanstveni članek

Opis: The electroanalytical and surface characterization of copper immersed in 3 wt.% NaCl solution containing 1 mM of 2-phenylimidazole (2PhI) is presented. It was proven that 2PhI can be employed as corrosion inhibitor for copper using various electrochemical analyses, such as cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy, and potentiodynamic curve measurements. The adsorption of 2PhI on copper was further analyzed by 3D-profilometry, attenuated total reflectance Fourier transform infrared spectroscopy, contact angle measurements, and scanning electron microscopy equipped with an energy dispersive X-ray spectrometer. This system was therefore comprehensively described by various analytical approaches.
Ključne besede: corrosion inhibitor, copper, electrochemical impedance spectroscopy, EIS, cyclic voltammetry, attenuated total reflectance Fourier transform infrared, ATR-FTIR
Objavljeno: 17.01.2019; Ogledov: 708; Prenosov: 252
.pdf Celotno besedilo (5,88 MB)
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4.
Probing ion dynamics in a clay-water system with dielectric spectroscopy
Marko Samec, Dean Korošak, Bruno Cvikl, 2007, izvirni znanstveni članek

Opis: Dielectric spectroscopy characterization of clay-water mixtures is presented and the obtained spectra are analysed. A theoretical model for ion dynamics isproposed in which motion of ions in pore space electrolyte is interrupted by trapping events at the mineral surfaces. The typical time scales for these processes are given in terms of the physical properties of the material. It isshown that the microscopic motion of the ions in a complex environment of clay-water system can be described with fractional dynamics leading to subdiffusive behavior.
Ključne besede: soil mechanics, dielectric spectroscopy, porous material, conductivity, fractional dynamics
Objavljeno: 18.05.2018; Ogledov: 385; Prenosov: 61
.pdf Celotno besedilo (105,00 KB)
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5.
Determination of topiramate in human plasma using liquid chromatography tandem mass spectrometry
Tanja Vnučec, Lea Cvitkovič-Maričič, Helena Prosen, Darinka Brodnjak-Vončina, 2013, izvirni znanstveni članek

Opis: The LC-MS/MS method for determination of the anti-epileptic drug topiramate (TPM) in human plasma was developed and validated for pharmacokinetic and bioequivalence study purposes. For quantitative determination of TPM values the method with deuterated internal standard (topiramate-d12) and liquid chromatography with tandem mass spectrometry was used. TPM was extracted from the human plasma using the solid-phase extraction procedure on a Strata X extraction column. Negative ions were monitored in the selected reaction monitoring mode (SRM) and transitions m/z 338.2 > 78.2 and m/z 350.3 > 78.2 were used for the quantitative evaluation of TPM and the internal standard, respectively. The results obtained from validation were statistically evaluated according to the requirements of European Medicines Agency (EMA) and Food and Drug Administration (FDA) regulatory guidelines. The linearity of the method was checked within a concentration range from 10 to 2000 ng/mL. Successful validation confirmed that this method is precise, accurate, sensitive and therefore suitable for determination of topiramate plasma levels in pharmacokinetic and bioequivalence studies.
Ključne besede: topiramate, liquid chromatography tandem mass spectroscopy, human plasma, bioequivalence study
Objavljeno: 18.08.2017; Ogledov: 756; Prenosov: 54
.pdf Celotno besedilo (189,19 KB)
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6.
Determination of microstructural changes by severely plastically deformed copper-aluminum alloy
Nebojša Romčević, M. Gilić, Ivan Anžel, Rebeka Rudolf, Miodrag Mitrić, M. Romčević, B. Hadžić, D. Joksimović, Milica Petrović Damjanović, Matija Kos, 2014, izvirni znanstveni članek

Opis: Our work deals with the problem of producing a complex metal-ceramic composite using the processes of internal oxidation (IO) and severe plastic deformation. For this purpose, Cu-Al alloy with 0.4wt.% of Al was used. IO of sample serves in the first step of the processing as a means for attaining a fine dispersion of nanosized oxide particles in the metal matrix. Production technology continues with repeated application of severe plastic deformation (SPD) of the resulting metal matrix composite to produce the bulk nanoscaled structural material. SPD was carried out with equal channel angular pressing (ECAP), which allowed that the material could be subjected to an intense plastic strain through simple shear. Microstructural characteristics of one phase and multiphase material was studied on internally oxidized Cu with 0.4wt.% of Al sample composed of one phase copper-aluminum solid solution in the core and fine dispersed oxide particles in the same matrix in the mantle region. In this manner AFM, X-ray diffraction and Raman spectroscopy were used. Local structures in plastically deformed samples reflect presence of $Cu$, $CuO$, $Cu_2O$, $Cu_4O_3$ or $Al_2O_3$ structural characteristics, depending on type of sample.
Ključne besede: metals, oxides, atomic force microscopy, Raman spectroscopy, microstructure
Objavljeno: 08.08.2017; Ogledov: 666; Prenosov: 88
.pdf Celotno besedilo (596,63 KB)
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7.
Influence of the temperature on the efficiency of cellulose treatment using copolymer chitosan-eugenol
Olivera Šauperl, Jasna Tompa, Julija Volmajer Valh, 2014, izvirni znanstveni članek

Opis: In order to achieve effective antimicrobial protection of textile materials against microorganisms, a natural compound called chitosan has become very interesting. In regard to the antimicrobial protection of textile materials, functionalization with chitosan does not affect some other properties, such as anti-oxidative or any other action. For this reason, it seems appropriate for chitosan to be combined with any natural antimicrobial active compound, such as eugenol, an extract of clove oil. During this research viscose as a representative of cellulose fibers was used, because it can be functionalized relatively easily. In terms of functionalization, the drying temperature of viscose, after antimicrobial compound application onto substrate, as well as the successful synthesis of copolymer chitosan/eugenol is also important. FTIR spectroscopy was used to evaluate the efficiency of synthesizing a chitosan/eugenol graft copolymer. The spectrophotometric method Acid Orange 7 was chosen as a means for determining the proportion of available antimicrobial active amino groups. In addition, microbiological testing of selected pathogenic micro-organisms was also performed. The results were compared with the results for viscose functionalized by a 1% solution of chitosan.
Ključne besede: chitosan, eugenol, functionalization, viscose, FTIR spectroscopy, Acid orange 7, antimicrobial
Objavljeno: 02.08.2017; Ogledov: 498; Prenosov: 317
.pdf Celotno besedilo (233,00 KB)
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8.
An innovative approach to near-infrared spectroscopy using a standard mobile device and its clinical application in the real-time visualization of peripheral veins
Simon Jurič, Borut Žalik, 2014, izvirni znanstveni članek

Opis: Background: Excessive venipunctures are a significant problem both in emergency rooms and during hospital stays. Near-infrared (NIR) illumination devices improve venipuncture success rate but their usage is limited by their availability and economic cost. The objectives of this study were to develop a low-cost NIR spectroscopy prototype from a standard mobile device, to evaluate its efficacy and acceptance as an educational tool, and in a clinical setting. Methods: Through a user-centric design process a prototype device was developed. Its educational efficacy was evaluated through a non-invasive, observational study (20 student clinicians, 25 subjects) and its acceptance was assessed using quantitative and qualitative analysis. A smaller clinical trial was performed by a group of 4 medical professionals over a period of 6 weeks that involved 64 patients. Results: The prototype enables real-time visualization of peripheral veins on a variety of Android-based devices. The prototype was 35.2% more successful in visualizing and locating veins (n = 500 attempts) than the nursing students. The acceptance assessment revealed high perception of usefulness, satisfaction, and ease of use. In the clinical trial, 1.6 (SD 1.3) additional veins per patient were identified compared with the traditional visualization methods. Conclusions: To the best of our knowledge this is the first study that describes the design, feasibility and application of an NIR spectroscopy prototype developed on a standard mobile device.
Ključne besede: mobile applications, spectroscopy, near-infrared, NIRS, vascular access devices, health education, feasibility
Objavljeno: 29.06.2017; Ogledov: 705; Prenosov: 306
.pdf Celotno besedilo (2,32 MB)
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9.
Towards a low-cost mobile subcutaneous vein detection solution using near-infrared spectroscopy
Simon Jurič, Vojko Flis, Matjaž Debevc, Andreas Holzinger, Borut Žalik, 2014, pregledni znanstveni članek

Opis: Excessive venipunctures are both time- and resource-consuming events, which cause anxiety, pain, and distress in patients, or can lead to severe harmful injuries. We propose a low-cost mobile health solution for subcutaneous vein detection using near-infrared spectroscopy, along with an assessment of the current state of the art in this field. The first objective of this study was to get a deeper overview of the research topic, through the initial team discussions and a detailed literature review (using both academic and grey literature). The second objective, that is, identifying the commercial systems employing near-infrared spectroscopy, was conducted using the PubMed database. The goal of the third objective was to identify and evaluate (using the IEEE Xplore database) the research efforts in the field of low-cost near-infrared imaging in general, as a basis for the conceptual model of the upcoming prototype. Although the reviewed commercial devices have demonstrated usefulness and value for peripheral veins visualization, other evaluated clinical outcomes are less conclusive. Previous studies regarding low-cost near-infrared systems demonstrated the general feasibility of developing cost-effective vein detection systems; however, their limitations are restricting their applicability to clinical practice. Finally, based on the current findings, we outline the future research direction.
Ključne besede: subcutaneous vein detection, diagnostic methods and procedures, infrared rays, spectroscopy, vascular diseases, mobile devices
Objavljeno: 15.06.2017; Ogledov: 707; Prenosov: 285
.pdf Celotno besedilo (2,36 MB)
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10.
Modification of PET-polymer surface by nitrogen plasma
Rok Zaplotnik, Metod Kolar, Aleš Doliška, Karin Stana-Kleinschek, 2011, izvirni znanstveni članek

Opis: Low pressure weakly nitrogen plasma was applied for incorporation of nitrogen-containing functional groups onto poly(ethylene terephthalate) - PET polymer. Nitrogen plasma was created in an electrode-less radiofrequency discharge at the nominal power of 200 W and the frequency of 27.12 MHz. Nitrogen molecules entered the discharge region were highly excited, partially dissociated and weakly ionized. Transformation into the state of plasma allowed for creation of chemically reactive particles with a high potential energy while the kinetic energy remained close to the value typical for room temperature. The chemical reactivity allowed for rapid functionalization with nitrogen-rich functional groups. The appearance of these groups was monitored by X-ray photoelectron spectroscopy - XPS. The polymer surface was quickly saturated with nitrogen indicating that the modification was limited to an extremely thin surface film.
Ključne besede: poly(ethylene terephthalate), nitrogen plasma, surface modification, functional groups, X-ray photoelectron spectroscopy
Objavljeno: 17.03.2017; Ogledov: 496; Prenosov: 78
.pdf Celotno besedilo (150,48 KB)
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