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2. Quasi-static and impact behaviour of polymer-metal interpenetrating phase TPMS compositesNejc Novak, Oraib Al-Ketan, Anja Mauko, Lovre Krstulović-Opara, Shigeru Tanaka, Matej Borovinšek, Boštjan Vihar, Uroš Maver, Kazuyuki Hokamoto, Matej Vesenjak, Zoran Ren, 2025, original scientific article Abstract: Interpenetrating phase composites (IPC) are materials with two or more mutually continuous, interconnected phases. This structure allows each phase to retain its properties, while together they exhibit enhanced synergistic properties. In this work, polymer-metal IPCs with Triply Periodical Minimal Surface (TPMS) structures were fabricated and tested for their mechanical properties at different impact velocities (ranging from 0.1 mm/s to 250 m/s). Samples. The samples comprise a stainless steel reinforcement phase and two polymeric matrices (silicone and epoxy). Computed tomography was used to evaluate the internal structure and the fabrication quality. The results showed that the samples were thoroughly infiltrated with polymeric filler, achieving a high degree of homogeneity in the composite. The compression tests of silicone-filled IPCs showed an increase in stiffness. Still, the Specific Energy Absorption (SEA) was not improved due to the non-optimal stiffness ratio between the polymeric matrix and the metallic reinforcement phase. However, using epoxy as the matrix resulted in the SEA enhancement of 38 %. This is attributed to the interlocking mechanism between the two phases, which improved the macroscopic mechanical properties. The compression tests showed significant strain rate hardening due to the base material’s strain rate sensitivity and the inertia effects.
Keywords: TPMS, interpenetrating phase composite, polymer filler, hybrid structure, experimental testing, mechanical properties, strain rate effect
Published in DKUM: 26.05.2025; Views: 0; Downloads: 4
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3. Vpliv uvedbe empagliflozina ali semaglutida na delovanje endotelija in podajnost arterij ter druge klinične parametre in laboratorijske označevalce pri osebah s sladkorno boleznijo tipa 1Maja Navodnik Preložnik, 2025, doctoral dissertation Abstract: Sladkorna bolezen predstavlja pomemben dejavnik tveganja srčno-žilne obolevnosti in umrljivosti, okrnjeno delovanje endotelija predstavlja najzgodnejše spremembe v procesu ateroskleroze.
V doktorski disertaciji sem se poglobila v delovanje in funkcijo endotelija. V raziskavi smo proučevali učinek dodatnega zdravljenja z novejšimi antidiabetičnimi zdravili na delovanje endotelija s funkcionalnimi meritvami in laboratorijskimi označevalci pri dobro urejenih osebah s sladkorno boleznijo tipa 1 (SB1) brez srčno-žilnih bolezni.
89 udeležencev, uporabnikov sistema za neprekinjeno spremljanje glukoze (CGMS – angl. continuous conitoring glucose system), je bilo randomiziranih v tri primerljive skupine, ki so prejemale empagliflozin (E; n=30), semaglutid (S; n=30) in kontrolno skupino (C; n=29). Ob vključitvi in 12 tednov po zdravljenju smo izmerili: postishemične hemodinamske spremembe brahialne arterije (FMD – flow mediated dilation), pri katerih ocenjujemo s povečanim pretokom povzročeno dilatacijo in postishemične spremembe v tkivnem pretoku podlahti (FBF – angl. forearm blood flow) zaradi reaktivne hiperemije, ocenjene z uporovno pletizmografijo kot parametra endotelne funkcije, ter hitrost pulznega vala (PWV – angl. pulse wave velocity) in periferni upor kot parametra arterijske togosti oz. podajnosti. Ocenili smo biološke označevalce endotelne funkcije: endotelne progenitorne celice (EPC) in cirkulirajoče endotelne celice (CEC), laboratorijske označevalce vnetja (interleukin 6, selektin E, TNFα, VCAM, hsCRP), vazoaktivno snov endotelin 1, in prokoagulabilni faktor vWF.
Izboljšanje FMD smo potrdili v obeh intervencijskih skupinah v primerjavi s kontrolami (skupina E 2.0-krat, p = 0.000٭ in skupina S 1.9-krat, p = 0.000٭), med tema dvema skupinama pa ni bilo sprememb (p = 0.745). Med ocenjevanjem FBF je bilo v obeh terapevtskih skupinah v primerjavi s kontrolami statistično nepomembno izboljšanje (skupina E 1.39-krat, p = 0.074 in skupina S 1.22-krat, p = 0.701). Pri parametrih arterijske togosti smo izboljšave opazili le v skupini s semaglutidom, pri čemer se je periferni upor zmanjšal za 5.1 % (p = 0.046٭).
Potrdili smo tudi pomembno povečanje EPC v obeh intervencijskih skupinah v primerjavi s kontrolami (E-C; p = 0.021* in S-C; p = 0.031*), medtem ko med obema skupinama zdravljenja ni bilo razlike (p = 0.852). Empagliflozin je delež EPC zvišal za 2.5-krat (p = 0.002٭) in semaglutid za 2.16-krat (p = 0.001٭). Zmanjšanje CEC smo potrdili pri skupini, zdravljeni s semaglutidom (p = 0.014*).
Po zdravljenju s semaglutidom smo potrdili znižanje vnetnih označevalcev hsCRP za -0.25 mmol/l (-10.6, 21) (p = 0.024)٭, selektina E za -1.94 μg/l (-12.69, 4.83, p = 0.004٭) in TNFα za -1.94 (-6.6, 3.4) (p = 0.001٭), nakazovalo se je znižanje tudi ostalih bioloških označevalcev vnetja, medtem ko na te markerje empagliflozin ni imel nobenega vpliva.
Empagliflozin ali semaglutid pri osebah s SB1 enakovredno znižata HbA1C, TIR (angl.time in range - čas v ciljnem območju glikemije), glukovariabilnost, telesno težo, obseg trebuha in odmerek inzulina, na znižanje LDL pa vpliva le semaglutid. Obe zdravili enakovredno izboljšujeta funkcijo endotelija makrovaskularizacije, ocenjeno s FMD in da verjetno izboljšujeta funkcijo endotelija mikrovaskularizacije, ocenjeno s FBF. Pri vplivu na podajnost oz. togost arterij, označevalce vnetja in upad CEC ima prednost semaglutid. Obe zdravili tudi enakovredno povečujeta izplavljanje EPC in imata tako zaščitno vlogo pri osebah s SB1.
Keywords: endotelna disfunkcija, biološki označevalci, empagliflozin, semaglutid, sladkorna bolezen tip 1
Published in DKUM: 16.05.2025; Views: 0; Downloads: 6
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4. Artificial biomimetic electrochemical assembliesTanja Zidarič, Matjaž Finšgar, Uroš Maver, Tina Maver, 2022, review article Abstract: 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.
Keywords: MIP-based biosensors, MIP, biosensors, molecularly imprinted polymer, biomolecules, electroanalysis
Published in DKUM: 15.05.2025; Views: 0; Downloads: 0
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5. Synergistic effect of supercritical and ultrasound-assisted ginger (Zingiber officinale Roscoe) extractsTaja Žitek Makoter, Nika Kučuk, Vesna Postružnik, Maja Leitgeb, Željko Knez, Mateja Primožič, Maša Knez Marevci, 2022, original scientific article Abstract: Proper processing of natural material is crucial to obtain an extract with high content of
biologically active components. Dried, grinded ginger roots were extracted by ultrasonic method
and supercritical extraction with CO2
. The aim of the study was to determine if a mixture of the two
types of extracts attained by different methods and solvents exhibits better bioavailability than each
extract itself. Therefore, both extracts were analytically evaluated and then mixed in a ratio of 1:1.
The supercritical extract (SCG extract) and the mixed extract (mixG extract) had high antioxidant
activity (78% and 73%) and total phenols (827 mg/g ext. and 1455 mg/g ext.), which is also consistent
with the levels of gingerol (303 mg/g ext. and 271 g/g ext.) and shogaol (111 mg/g ext. and 100 g/g
ext.) in the extracts. In comparison to both pure extracts higher levels of total phenols were found
in the extract mixG. This could be the reason for the significant inhibition of melanoma cells and
antimicrobial potential (against Staphylococcus aureus, Escherichia coli, and Candida albicans). The
combination of the extracts resulted in a significant increase in the inhibition of selected microbial
and melanoma cells WM-266-4 compared to the control. Cell viability decreased below 60% when
mixG extract was applied. Antimicrobial activity has been confirmed.
Keywords: ginger, supercritical fluid extraction, ultrasound-assisted extraction, antimicrobial activity
Published in DKUM: 09.05.2025; Views: 0; Downloads: 2
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6. Optimisation of the green process of industrial hemp - preparation and its extract characterisationTaja Žitek Makoter, Petra Kotnik, Teo Makoter, Vesna Postružnik, Željko Knez, Maša Knez Marevci, 2022, original scientific article Abstract: Natural medicines and products are becoming increasingly important in the pharmaceutical
and food industries. The most important step in obtaining a natural remedy is the processing of
the natural material. This study offers the separation of the industrial hemp plant into fractions by
mechanical treatment, which has a significant impact on the selectivity of the obtained fractions. This
study also offers a solution to reduce waste by fractionating industrial hemp, focusing on the fraction
with the highest cannabinoid content (49.5% of CBD). The study confirmed the anticancer potential
of the extract, which prevents further division of WM-266-4 melanoma cells at a concentration of
10−3 mg/mL. However, application of the extract (c = 10−3 mg/mL) to normal human epidermal
melanocytes proved to be insignificant, as the metabolic activity of the cells was the same as in the
control cell group.
Keywords: supercritical fluid extraction, ultrasonic extraction, melanoma cells, extraction, WM-266-4
Published in DKUM: 09.05.2025; Views: 0; Downloads: 2
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7. Dolgoročne posledice z mastoidektomijo zdravljenega akutnega mastoiditisaMatija Švagan, 2025, doctoral dissertation Abstract: Izhodišča: Akutni mastoiditis (AM) in z njim povezani zapleti, ki so posledica akutnega gnojnega vnetja srednjega ušesa, se kljub razširjeni uporabi antibiotikov še vedno pojavljajo, najpogosteje pri otrocih. Medtem ko številne študije preučujejo patogenezo, povzročitelje in zdravljenje akutnega mastoiditisa, manjkajo študije, ki bi celovito preučile dolgoročne posledice prebolelega AM in fiziološke posledice kirurškega posega v temporalno kost.
Metode: Kohorto bolnikov, ki so zaradi AM prejeli kirurško zdravljenje v obliki mastoidektomije, smo povabili na testiranje vsaj pet let po operaciji. Preiskava je vključevala vprašalnik COMQ-12, klinični pregled in otomikroskopijo, razširjeno visokofrekvenčno pražno tonsko avdiometrijo, DPOAE, impedančne meritve srednjega ušesa in testiranje funkcije mastoida z novo razvitim protokolom za neinvazivno merjenje funkcije mastoida. Rezultate smo primerjali s kontrolno skupino in skupino, ki je za akutni otitis media z nevarnostjo mastoiditisa prejela kirurško zdravljenje samo v obliki timpanostomije. Vsaka izmed skupin je vsebovala 30 testiranih ušes, skupaj 90.
Rezultati: V vprašalniku COMQ-12 smo ugotovili, da imajo bolniki po mastoidektomiji nekoliko več težav s sluhom v tihem okolju, s sluhom v hrupu, več zaznave tinitusa in neprijetnega občutka okoli ušesa. Pri otomikroskopiji so bile v testnih skupinah opažene manjše strukturne spremembe, ne pa tudi v kontrolni skupini. Tonska avdiometrija je pokazala za približno 10 dB višje pražne vrednosti pri visokih in razširjenih visokih frekvencah, podobno kot pri testu DPOAE. Pri testiranju upornosti srednjega ušesa je bilo zaznano le zvišanje praga stapedialnega refleksa; drugi testi niso pokazali statistično značilnih razlik. Testiranje funkcije mastoida je pri bolnikih z mastoidektomijo pokazalo ohranjeno funkcijo tlačnega pufra in zmanjšano zmožnost toplotne izolacije ravnotežnega organa ob ekstremni toplotni stimulaciji, ki pa se v vsakdanjem življenju redko pojavi.
Zaključek: Dolgoročno ima večina bolnikov po prebolelem AM le manjše funkcionalne in strukturne posledice. V kontekstu zdravljenja AM so učinki mastoidektomije zanemarljivi v primerjavi z manj invazivnimi kirurškimi posegi.
Keywords: akutni mastoiditis, mastoidektomija, dolgoročne posledice, otroška otorinolaringologija
Published in DKUM: 08.05.2025; Views: 0; Downloads: 9
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8. Effect of green food processing technology on the enzyme activity in spelt flourMaja Leitgeb, Željko Knez, Gordana Hojnik Podrepšek, 2022, original scientific article Abstract: In this research, a new approach to enzyme inactivation in flour was presented by supercritical
technology, considered a sustainable technology with lower energy consumption compared
to other technologies that use ultra-high temperature processing. Total protein concentration and
the activity of enzymes α-amylase, lipase, peroxidase, polyphenol oxidase, and protease were determined
in flour pre-treated with scCO2. During the study, it was observed that the activity of enzymes
such as lipase and polyphenol oxidase, was significantly reduced under certain conditions of scCO2
treatment, while the enzymes α-amylase and protease show better stability. In particular, polyphenol
oxidase was effectively inactivated below the 60% of preserved activity at 200 bar and 3 h, whereas
α-amylase under the same conditions retained its activity. Additionally, the moisture content of the
scCO2-treated spelt flour was reduced by 5%, and the fat content was reduced by 58%, while the
quality of scCO2-treated flour was maintained. In this regard, the sustainable scCO2 process could be
a valuable tool for controlling the enzymatic activity of spelt flour since the use of scCO2 technology
has a positive effect on the quality of flour, which was verified by the baking performance of spelt
flour with the baked spelt bread as an indicator of quality.
Keywords: food treatment, spelt flour, proteins, supercritical carbon dioxide, enzyme inactivation, defatted flour, carbon dioxide solubility
Published in DKUM: 17.04.2025; Views: 0; Downloads: 1
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9. Participation in youth sports influences sarcopenia parameters in older adultsKaja Teraž, Miloš Kalc, Boštjan Šimunič, Uroš Marušič, Primož Pori, Saša Pišot, Rado Pišot, 2023, original scientific article Abstract: Background: The degree of deterioration in sarcopenia parameters may be affected by a person’s level of physical activity (PA) and sedentary behavior (SB). Our study focused on examining the PA and SB of active older adults including those with and without history of sports in youth.
Methods: Forty-four participants (20 men and 24 women, mean age of total sample 76.1 ± 5.2 years) were included in analysis of PA, SB habits and sarcopenia parameters, determined by skeletal muscle index, hand-grip strength, gait speed, Timed Up and Go tests (TUG). PA and SB were recorded with accelerometers. Our primary aim was to compare participants with (AH) or without a sport history in youth (NAH), in their sarcopenia parameters and PA and SB habits.
Results: When divided participants in two groups (AH and NAH) and adjusting for age, we have detected the differences for skeletal muscle index (p = 0.007) and hand-grip strength (p = 0.004) in favor of participants who were engaged in sports in youth. We did not find any differences in PA and SB habits between the AH and NAH groups. After adjusting for age, participants with a higher number of daily steps, longer moderate to vigorous physical activity (MVPA) bouts, a higher number of MVPA bouts in a day and higher overall MVPA engagement achieved better results in hand-grip strength and TUG. Participants with lower SB had better TUG and gait speed results.
Conclusions: Our findings suggest that engaging in sports activities in youth can make a difference with sarcopenia parameters. Although we found no differences in PA and SB habits between participants with AH and NAH, participants with an athlete history performed better results in sarcopenia parameters.
Keywords: active ageing, muscles, muscle disorder, elderly, exercise, sedentarism
Published in DKUM: 15.04.2025; Views: 0; Downloads: 0
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10. MFUM-BrTNBC-1, a newly established patient-derived triple-negative breast cancer cell line : molecular characterisation, genetic stability, and comprehensive comparison with commercial breast cancer cell linesKristijan Skok, Lidija Gradišnik, Helena Sabina Čelešnik, Marko Milojević, Uroš Potočnik, Gregor Jezernik, Mario Gorenjak, Monika Sobočan, Iztok Takač, Rajko Kavalar, Uroš Maver, 2022, original scientific article Abstract: Triple-negative breast cancer (TNBC) is a breast cancer (BC) subtype that accounts for
approximately 15–20% of all BC cases. Cancer cell lines (CLs) provide an efficient way to model the
disease. We have recently isolated a patient-derived triple-negative BC CL MFUM-BrTNBC-1 and
performed a detailed morphological and molecular characterisation and a comprehensive comparison
with three commercial BC CLs (MCF-7, MDA-MB-231, MDA-MB-453). Light and fluorescence
microscopy were used for morphological studies; immunocytochemical staining for hormone receptor,
p53 and Ki67 status; RNA sequencing, qRT-PCR and STR analysis for molecular characterisation; and
biomedical image analysis for comparative phenotypical analysis. The patient tissue-derived MFUMBrTNBC-1 maintained the primary triple-negative receptor status. STR analysis showed a stable and
unique STR profile up to the 6th passage. MFUM-BrTNBC-1 expressed EMT transition markers and
displayed changes in several cancer-related pathways (MAPK, Wnt and PI3K signalling; nucleotide
excision repair; and SWI/SNF chromatin remodelling). Morphologically, MFUM-BrTNBC-1 differed
from the commercial TNBC CL MDA-MB-231. The advantages of MFUM-BrTNBC-1 are its isolation
from a primary tumour, rather than a metastatic site; good growth characteristics; phenotype identical
to primary tissue; complete records of origin; a unique identifier; complete, unique STR profile;
quantifiable morphological properties; and genetic stability up to (at least) the 6th passage.
Keywords: hormonal receptors, MFUM-BrTNBC-1, MCF-7, MDA-MB-231, MDA-MB-453
Published in DKUM: 10.04.2025; Views: 0; Downloads: 4
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