University of Maribor

About: University of Maribor is a education organization based out in Maribor, Slovenia. It is known for research contribution in the topics: Population & KEKB. The organization has 3987 authors who have published 13077 publications receiving 258339 citations. The organization is also known as: Univerza v Mariboru.

Controlled surface functionalization of silica-coated magnetic nanoparticles with terminal amino and carboxyl groups

Abstract: General and versatile methods for the functionalization of superparamagnetic, silica-coated, maghemite nanoparticles by surface amino and/or carboxyl groups have been established. The nanoparticles were synthesized using co-precipitation from aqueous solutions and coated with a thin layer of silica using the hydrolysis and condensation of tetraethoxysilane (TEOS). For the amino functionalization, 3-(2-aminoethylamino)propylmethyldimethoxysilane (APMS) was grafted onto the nanoparticle surfaces in their aqueous suspensions. The grafting process was followed by measurements of the ζ-potential and a determination of the concentration of the surface amino groups with conductometric titrations. The surface concentration of the amino groups could be varied by increasing the amount of APMS in the grafting process up to approximately 2.3 –NH2 groups per nm2. The carboxyl functionalization was obtained in two ways: (i) by a ring-opening linker elongation reaction of the surface amines at the functionalized nanoparticles with succinic anhydride (SA) in non-aqueous medium, and (ii) by reacting the APMS and SA first, followed by grafting of the carboxyl-terminated reagent onto the nanoparticle surfaces. Using the first method, the SA only reacted with the terminal primary amino groups (–NH2) of the surface-grafted APMS molecules. Infra-red spectroscopy (ATR FTIR) and mass spectrometry (HRMS) showed that the second method enables the bonding of up to two SA molecules per one APMS molecule, since the SA reacted with both the primary (–NH2) and secondary amino (–NH–) groups of the APMS molecule. When using both methods, the ratio between the surface amino and carboxyl groups can be controlled.

Application of measurements of transepithelial electrical resistance of intestinal epithelial cell monolayers to evaluate probiotic activity.

Abstract: Among five potentially probiotic lactobacilli investigated, Lactobacillus plantarum MF1298 and Lactobacillus salivarius DC5 showed the highest increase in the transepithelial electrical resistance (TER) of polarized monolayers of Caco-2 cells, and this increase was shown to be dose dependent. Furthermore, preincubation with MF1298 attenuated a decrease in TER induced by Listeria monocytogenes.

Travel time model for shuttle-based storage and retrieval systems

Abstract: This paper presents analytical travel time model for the computation of travel (cycle) time for shuttle-based storage and retrieval systems (in continuation SBS/RS). The proposed model considers the operating characteristics of the elevators lifting table and the shuttle carrier, such as acceleration and deceleration and the maximum velocity. Assuming uniform distributed storage rack locations and using the probability theory, the expressions of the cumulative distribution functions with which the mean travel time is calculated, have been determined. The proposed model enables the calculation of the mean travel (cycle) time for the single and dual command cycles, from which the performance of SBS/RS can be evaluated. The approximation model and a simulation model of SBS/RS have been used to compare the performances of the proposed analytical travel time model. The analysis shows that regarding all examined types of SBS/RS, the results of proposed analytical travel time model for SBS/RS correlate with the results of simulation models of SBS/RS.