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Abstract: We investigated micro-threaded stem taper surface and its impact on premature failures, aseptic loosening, and infection in cementless hip endoprostheses. Our study focused on the fretting, and crevice corrosion of micro-threaded tapers, as well as the characterization of the microstructure and surface properties of two new and three retrieved Zweymüller stem tapers. The retrieved samples were selected and examined based on the head–stem taper interface being the sole source of modularity with a metallic component, specifically between the Ti alloy taper stem and the ceramic head. To determine the surface chemistry and microstructures of both new and retrieved hip endoprostheses stem taper titanium alloy, scanning -electron microscopy (SEM) was employed for morphological and microstructural analyses. Energy dispersive spectroscopy (EDS) was utilized for characterizing chemical element distribution, and electron backscattered diffraction (EBSD) was used for phase analysis. The roughness of the micro-threated stem tapers from different manufacturers was investigated using an optical profilometer, with standard roughness parameters Ra (average surface roughness) and Rz (mean peak to valley height of the roughness profile) being measured. Electrochemical studies revealed no fretting corrosion in retrieved stem tapers with ceramic heads. Consequently, three retrieved tapers and two new ones for comparison underwent potentiodynamic measurements in Hank’s solution to determine the corrosion rate of new and retrieved stem taper surfaces. The results showed a low corrosion rate for both new and prematurely failed retrieved samples due to aseptic loosening. However, the corrosion rate was higher in infected and low-grade infected tapers. In conclusion, our study suggests that using ceramic heads reduces taper corrosion and subsequently decreases the incidence of premature failures in total hip arthroplasty.
Keywords: total hip arthroplasty, stem micro-threaded taper, taper surface morphology, microstructure, corrosion, Ti implant alloy
Published in DiRROS: 06.06.2024; Views: 475; Downloads: 345
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Abstract: The pedunculate oak (Quercus robur L.) is economically and ecologically one of the most significant tree species in Serbia, however, little is known about the influence of the riverbed distance and its water supply on ecophysiological responses of this species. Given the limited information on the light-response curve of photosynthesis for oaks in southwest Srem, Serbia, the aim of this paper is to enhance understanding of their ecophysiological responses in this context. Maximum assimilation rate (Amax), the quantum yield (Ф), and light compensation point (LCP) were compared in adult trees situated along the transect from the river: (1) close to the river, (2) intermediate, (3) farthest from the river, and (4) forest reserve (second closest), with the first three transects being managed forests and the last one being an unmanaged forest reserve. The measurements were conducted in July during the first evidence of drought. The highest Amax rates were measured in all light intensities on the site closest to the river and the smallest on the site that was most distant to the water source. The most efficient were trees close to the river and the ones in the forest reserve. No significant difference between compensation points was confirmed for the studied groups of trees, although the forest reserve trees showed slightly higher values. The results demonstrated clear response between transects, which followed the distance from the riverbed. Pedunculate oak's reliance on groundwater is in tight relation with ecophysiological processes in trees; groundwater depletion may threaten its survival in areas distant from the river.
Keywords: Quercus robur L., floodplain forest, drought, light-response curves, transects
Published in DiRROS: 05.06.2024; Views: 1528; Downloads: 245
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Abstract: Število žensk, ki so se zdravile zaradi ginekoloških rakov, se veča zaradi staranje populacije, zgodnjega odkrivanja bolezni in bolj uspešnih načinov zdravljenja. Rak in zdravljenje raka prizadenejo ženske na več nivojih, fizično in psihično. Najpogostejše težave so kronične bolečine, utrujenost, limfedem, nevropatija, anksioznost in depresija. Ginekološki raki in njihovo zdravljenje imajo dodatno še pomemben negativen vpliv tudi na spolno življenje. Spremljanje bolnic po zdravljenju raka zato ni namenjeno samo zgodnjemu odkrivanju morebitne ponovitve bolezni, ampak tudi zagotavljanju čim boljše kakovosti življenja. Pomembno in potrebno je, da pri bolnicah po zdravljenju ginekoloških rakov prepoznamo in lajšamo težave, ki so posledica bodisi bolezni same ali pa posledica zdravljenja raka. Načini in organizacija spremljanja bolnic z ginekološkimi raki se močno razlikuje med posameznimi centri in državami, jasnih dokazov, kateri je najboljši način dela, ni. Verjetnost ponovitve bolezni se razlikuje glede na vrsto raka, stadij bolezni, stanje bolnice in glede na to, kako je bila zdravljena, zato je tudi spremljanje smiselno prilagoditi posameznici, kar poudarja večina sodobnih smernic. Ginekološki raki predstavljajo heterogeno skupino bolezni. Mednarodna in domača priporočila o spremljanju so narejena za posamezne lokalizacije in so na kratko predstavljena v prispevku.
Keywords: rak (medicina), ginekologija, ponovitev bolezni, kakovost življenja, strokovna priporočila
Published in DiRROS: 04.06.2024; Views: 456; Downloads: 138
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Abstract: Podatki se nanašajo na petrološko analizo rečnih pliocensko-pleistocenskih sedimentov iz 14 prodnatih vzorcev iz slovenjgraškega, nazarskega, celjskega in dravsko-ptujskega bazena (severovzhodna Slovenija), ki so bili vzorčeni za namen litološke analize klastov. Petrološka analiza obsega opise 155 zbruskov metamorfnih, vulkanskih, vulkanoklastičnih, klastičnih in karbonatnih kamnin. Ti podatki predstavljajo temelj za določitev provenience obravnavanih prodnatih sedimentov, razkrivajo morebitno resedimentacijo ter so pomembni za interpretacijo razvoja rečne mreže v pliocenu in pleistocenu.
Keywords: petrografska analiza, litološka analiza klastov, provenienca klastov, pliocensko-pleistocenski sedimenti
Published in DiRROS: 04.06.2024; Views: 723; Downloads: 640
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Abstract: Using a broad-based understanding of religious conversions which includes atheization and religious revival, the conference aims to address the issues related to religious transformation in Central and Eastern Europe in the 20th century and different types of religious agency that transcend established norms, legal frameworks and cultural expectations. The speakers will go beyond the usual concept of religious conversion as an exclusively individual, voluntary spiritual phenomenon and will examine conversions that embody the myriad motives, forms, and socio-political particularities which condition the changes of worldviews as a process that frequently encompasses obstacles, pragmatism and profound life alterations. The conf­erence will contribute to wide-ranging but – especially in Central and Eastern Europe – largely unexplored topics from a more nuanced understanding of the mechanisms that drive religious change and religion-state relations. Taking into account new research perspectives, scholars from the fields of history, anthropology, study of religions, ethnology, sociology, theology and political science will provide new insights into the following topics: - religious conversions as mechanisms for personal gain, coercive tactics and the (gradual) disestablishment of religious institutions; - state-imposed atheization processes; - religious upsurges of (non-)dominant religions, relations between religion and state, and the (re)shaping of religious policies in practise.
Published in DiRROS: 03.06.2024; Views: 442; Downloads: 318
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