Iskanje po katalogu digitalne knjižnice

Opis: Titanium and its alloys, as well as stainless steel, are commonly used materials for implants in the human body due to their excellent biocompatibility, corrosion resistance, and mechanical properties. However, the long-term performance of these materials in the oral cavity can be affected by the complex oral environment, including the ingestion of food, beverages, and oral hygiene products, leading to the presence of various ions, pH fluctuations, and inflammatory processes. In this study, the corrosion properties of two biocompatible materials, Ti6Al4V and AISI 316L stainless steel, are investigated under varying oral inflammatory conditions. Using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), SEM, and EDS analysis, the corrosion behaviour of both materials was analysed in environments simulating mild and severe inflammation. Results indicate that Ti6Al4V exhibits superior corrosion resistance at low H2O2 concentrations mimicking mild inflammation, with significantly lower corrosion rates compared to AISI 316L. However, at higher H2O2 concentrations, which correspond to severe inflammation, AISI 316L shows better resistance despite its susceptibility to pitting corrosion. Both alloys show reduced passivation after 72 h, with corrosion products accumulating on the surface after 96 h, contributing to repassivation. These results emphasise the need for individualized material selection in dental applications based on a patient’s susceptibility to oral inflammation.
Ključne besede: corrosion, EIS, inflammatory conditions, titanium, stainless steel, dental materials
Objavljeno v DKUM: 19.05.2025; Ogledov: 0; Prenosov: 0
Celotno besedilo (4,10 MB)

Opis: Rapid, selective, and cost-effective detection and determination of clinically relevant biomolecule analytes for a better understanding of biological and physiological functions are becoming increasingly prominent. In this regard, biosensors represent a powerful tool to meet these requirements. Recent decades have seen biosensors gaining popularity due to their ability to design sensor platforms that are selective to determine target analytes. Naturally generated receptor units have a high affinity for their targets, which provides the selectivity of a device. However, such receptors are subject to instability under harsh environmental conditions and have consequently low durability. By applying principles of supramolecular chemistry, molecularly imprinted polymers (MIPs) can successfully replace natural receptors to circumvent these shortcomings. This review summarizes the recent achievements and analytical applications of electrosynthesized MIPs, in particular, for the detection of protein-based biomarkers. The scope of this review also includes the background behind electrochemical readouts and the origin of the gate effect in MIP-based biosensors.
Ključne besede: MIP-based biosensors, MIP, biosensors, molecularly imprinted polymer, biomolecules, electroanalysis
Objavljeno v DKUM: 15.05.2025; Ogledov: 0; Prenosov: 0
Celotno besedilo (5,11 MB)
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Opis: The preconditioning and modification of the supporting electrode surface is an essential step in every biosensor architecture. In particular, when using screen-printed carbon electrodes (SPEs) as inexpensive and convenient disposable sensor substrates, their somewhat lower electrochemical (surface) reproducibility might represent a complex hurdle. Herein, we investigated the effect of selected preconditioning strategies, such as cyclic voltammetric pretreatment, in H2SO4 and H2O2 and plasma pretreatment with a positive and negative glow discharge, which all improved the electrochemical stability of the unmodified SPEs. Furthermore, we studied the influence of preconditioning strategies on the adsorption kinetics of the two most commonly used building blocks for biosensor preparation, i.e., bovine serum albumin (BSA) and protein A. We observed an advantageous effect of all the examined preconditioning strategies for the modification of SPEs with protein A, being the most effective the negative glow discharge. On the other hand, BSA exhibited a more complex adsorption behavior, with the negative glow discharge as the only generally beneficial preconditioning strategy providing the highest electrochemical stability. Protein A revealed a more substantial impact on the electrochemical signal attenuation than BSA considering their same concentrations in the modification solutions. For both BSA and protein A, we showed that the concentrations of 5 and 10 µg mL−1 already suffice for an electrochemically satisfactorily stable electrode surface after 60 min of incubation time, except for BSA at the positive-plasma-treated electrode.
Ključne besede: screen-printed carbon electrode, SPE, electrochemical biosensor, adsorption, bovine serum albumin, protein A, glow discharge
Objavljeno v DKUM: 15.05.2025; Ogledov: 0; Prenosov: 0
Celotno besedilo (1,23 MB)
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Opis: In addition to the consumption of hot utilities, there is also a significant cost associated with the consumption of cold utilities when there is a high demand for cooling. A promising solution for cooling is an absorption chiller (AC), which uses heat instead of electricity for cooling. A thermodynamic approach for evaluating AC integrated with a process is presented in this work. A model for assessing the properties and duties of an AC cycle was developed. The integration of a combined process-AC system was evaluated using the Grand Composite Curve. Three different options of integration were analyzed: (i) above the Pinch, (ii) below the Pinch, and (iii) across the Pinch. AC represents the combined effect of a heat engine and a heat pump, as the generator together with the absorber and condenser has the function of a heat engine, while the evaporator combined with the absorber and condenser mimics the function of a heat pump. The comparison between the non-integrated and integrated process-AC systems has revealed that the proper placement of AC is across or below the Pinch and the improper is above the Pinch. If AC was entirely integrated below the Pinch, the integration would result in a complete (100%) reduction in the consumption of hot utility for the operation of AC. The most suitable placement of AC with double reduction of hot utility consumption and complete reduction of both hot and cold utility to operate AC is across the Pinch due to the pumping of heat through AC from below to above the Pinch.
Ključne besede: absorption chiller, Pinch analysis, heat integration, low-temperature heat
Objavljeno v DKUM: 15.05.2025; Ogledov: 0; Prenosov: 1
Celotno besedilo (3,62 MB)
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Opis: 1,6-hexanediol diacrylate (HDDA) or divinyl adipate (DVA) and pentaerythritol tetrakis(3- mercaptopropionate) (TT) were polymerised via a thiol-ene radical initiated photopolymerisation using emulsions with a high volume fraction of internal droplet phase and monomers in the continuous phase as precursors. The porous structure derived from the high internal phase emulsions (HIPEs) followed the precursor emulsion setup resulting in an open porous cellularly structured polymer. Changing the emulsion composition and polymerisation conditions influenced the resulting morphological structure significantly. The investigated factors influencing the polymer monolith morphology were the emulsion phase ratio and surfactant concentration, leading to either interconnected cellular type morphology, bicontinuous porous morphology or a hollow sphere inverted structure of the polymerised monoliths. The samples with interconnected cellular morphology had pore diameters between 4 µm and 10 µm with approx. 1 µm sized interconnecting channels while samples with bicontinuous morphology featured approx. 5 µm wide pores between the polymer domains. The appropriate choice of emulsion composition enabled the preparation of highly porous poly(thiol-enes) with either polyHIPE or bicontinuous morphology. The porosities of the prepared samples followed the emulsion droplet phase share and could reach up to 88%.
Ključne besede: high internal phase emulsions, thiol-ene polymerisation, polyHIPE, bicontinuous structure, phase inversion, poly(thiol-enes)
Objavljeno v DKUM: 13.05.2025; Ogledov: 0; Prenosov: 0
Celotno besedilo (5,24 MB)
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