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Abstract: The potential use of steel slag from treated steel slag in belite-sulfoaluminate cements was investigated in this study. Cement clinkers with two phase compositions were synthesized, allowing the incorporation of different amounts of steel slag. The phase composition and microstructure of cement clinkers at three different sintering temperatures were studied by X-ray powder diffraction and the Rietveld method, as well as scanning electron microscopy with energy dispersive spectrometry. The results showed that the targeted phase composition of clinkers was achieved at a sintering temperature of 1250%C. However, a higher amount of perovskite instead of ferrite was detected in the clinker with a higher content of Ti-bearing bauxite. Apart from the main phases, such asbelite, calcium sulfoaluminate, and ferrite, several minor phases were identified, including mayenite, perovskite, periclase, and alkali sulfates. In both clinker mixtures, a higher content of MgO in the steelslags resulted in the formation of periclase. Furthermore, the hydration kinetics and compressive strength at 7 and 28 days were studied in two cements prepared from clinkers sintered at 1250%C. As evidenced by the results of isothermal calorimetry, the hydration kinetics were also influenced by the minor clinker phases. Cement with a higher content of calcium sulfoaluminate phase developed a higher compressive strength.
Keywords: cements, BCSA, steel slag, secundary row materials, microstructure, clinker phase
Published in DiRROS: 01.08.2023; Views: 329; Downloads: 163
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Abstract: V prispevku bomo predstavili rezultate fizikalnih modelov imunoterapije, ki smo jih razvili v programski skupini Medicinska fizika na Fakulteti za matematiko in fiziko Univerze v Ljubljani. Glavni cilj raziskav je bila prepoznava bioloških značilnosti tumorjev, od katerih je odvisen odziv na zdravljenje s protitelesi receptorja programirane celične smrti l (angl. anti-programmed-death-1 (anti-PD-1)). Posebno pozornost smo namenili meritvam modelskih parametrov ter preverbi rezultatov modeliranja, kar je eden izmed predpogojev za uspešno translacijo modeliranja v rutinsko predklinično in klinično prakso. Predstavili bomo tudi načrte za prihodnost, tj. modeliranje kombinacije anti-PD-1 in radioterapije.
Keywords: imunoterapija, radioterapija, medicinska fizika, tumorji
Published in DiRROS: 16.06.2023; Views: 447; Downloads: 115
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Abstract: The ever-growing worldwide demand for fired clay brick has resulted in the shortage of clay in many parts of the world. Therefore, there is a need to look for more sustainable alternative materials for the brick manufacturing. This study has investigated the potential use of the untreated Drava River sediment as a substitute material for clay in the production of fired bricks, with the research being conducted at both laboratory and industrial level. At the laboratory level, brick specimens were prepared by mixing clay with different river sediment proportions (ranging from 10 to 50 wt%) and were fired at 950 °C, with microstructural and various physical–mechanical properties being analyzed. Elevated carbonate content in Drava river sediment results in higher weight loss during firing at temperatures up to 950 °C, comparing to firing pure brick-making clay. Consequently, the addition of sediment increases porosity of fired bricks, which results in lowering of their mechanical properties. Results reveal that the compressive strength of the pure clay sample was 79.5 MPa, while the compressive strength of the sample with the addition of river sediment from 10 wt% to 50 wt% decreased from 73.9 MPa to 26.2 MPa, respectively. Despite the lower compressive strength, the 26.2 MPa is still above the limit value of 10 MPa specified in the standard EN 772–1 [1]. At the industrial level, hollow clay bricks were prepared with 20 wt% of the river sediment and fired in a tunnel kiln. Inclusion of the river sediment also decreased compressive strength from 38 MPa for pure mixture to 26 MPa for 20 wt% of the sediment addition, confirming usability of Drava sediment in brick production. In addition, LCA study has been conducted to evaluate the environmental impacts associated with the industrial production of classic bricks and bricks with the addition of the river sediment. The obtained results have shown that the bricks made with the addition of the Drava River sediment are sustainable and environmentally friendly and meet all the requirements specified in the relevant regulatory standard.
Keywords: sediments, clay masonry units, LCA, properties
Published in DiRROS: 30.05.2023; Views: 377; Downloads: 265
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Abstract: Background Sarcopenia is a common skeletal muscle syndrome that is common in older adults but can be mitigated by adequate and regular physical activity. The development and severity of sarcopenia is favored by several factors, the most influential of which are a sedentary lifestyle and physical inactivity. The aim of this observational longitudinal cohort study was to evaluate changes in sarcopenia parameters, based on the EWGSOP2 definition in a population of active older adults after eight years. It was hypothesized that selected active older adults would perform better on sarcopenia tests than the average population. Methods The 52 active older adults (22 men and 30 women, mean age: 68.4±5.6 years at the time of their first evaluation) participated in the study at two time points eight-years apart. Three sarcopenia parameters were assessed at both time points: Muscle strength (handgrip test), skeletal muscle mass index, and physical performance (gait speed), these parameters were used to diagnose sarcop0enia according to the EWGSOP2 definition. Additional motor tests were also performed at follow-up measurements to assess participants’ overall fitness. Participants self-reported physical activity and sedentary behavior using General Physical Activity Questionnaire at baseline and at follow-up measurements. Results In the first measurements we did not detect signs of sarcopenia in any individual, but after 8 years, we detected signs of sarcopenia in 7 participants. After eight years, we detected decline in ; muscle strength (-10.2%; p<.001), muscle mass index (-5.4%; p<.001), and physical performance measured with gait speed (-28.6%; p<.001). Similarly, self-reported physical activity and sedentary behavior declined, too (-25.0%; p=.030 and −48.5%; p<.001, respectively). Conclusions Despite expected lower scores on tests of sarcopenia parameters due to age-related decline, participants performed better on motor tests than reported in similar studies. Nevertheless, the prevalence of sarcopenia was consistent with most of the published literature. Trial registration The clinical trial protocol was registered on ClinicalTrials.gov, identifier: NCT04899531
Keywords: elderly, physical activities, sedentary behavior, skeletal muscle disorder, sarcopenia
Published in DiRROS: 29.05.2023; Views: 399; Downloads: 202
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Abstract: Leta 2019 je v Sloveniji zaradi pljučnega raka zbolelo okoli 1600 in umrlo preko 1200 ljudi, kar uvršča pljučni rak v enega izmed rakov z najslabšo prognozo. Petletna preživetja so slaba (okoli 20 %), preživetje pa je odvisno od razširjenosti obolenja. Polovico bolnikov odkrijemo v obdobju, ko je bolezen že razsejana in s tem neozdravljiva. Eno od možnosti zdravljenja pljučnega raka predstavlja sistemsko zdravljenje in enega od treh stebrov predstavlja kemoterapija (preostala dva sta tarčna terapija in zaviralci imunskih nadzornih točk). Kemoterapija podaljša preživetje bolnikov tako pri omejeni bolezni, kjer se uporablja perioperativno, kot pri lokalno napredovali bolezni, kjer se uporablja sočasno z obsevanjem in seveda tudi pri razsejani bolezni, kjer še vedno predstavlja pomembno modaliteto zdravljenja. Kemoterapijo uporabljamo kot samostojno zdravljenje ali v kombinaciji z zaviralci nadzornih točk.
Keywords: pljučni rak, onkološko zdravljenje, bolniki
Published in DiRROS: 12.05.2023; Views: 426; Downloads: 87
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