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Iskalni niz: "avtor" (Goran Dražić) .

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Nanoscale transformations of amphiboles within human alveolar epithelial cells
Ruggero Vigliaturo, Maja Jamnik, Goran Dražić, Marjetka Podobnik, Magda Tušek-Žnidarič, Giancarlo Della Ventura, Günther Redhammer, Nada Žnidaršič, Simon Caserman, Reto Gieré, 2022, izvirni znanstveni članek

Povzetek: Amphibole asbestos is related to lung fibrosis and several types of lung tumors. The disease-triggering mechanisms still challenge our diagnostic capabilities and are still far from being fully understood. The literature focuses primarily on the role and formation of asbestos bodies in lung tissues, but there is a distinct lack of studies on amphibole particles that have been internalized by alveolar epithelial cells (AECs). These internalized particles may directly interact with the cell nucleus and the organelles, exerting a synergistic action with asbestos bodies (AB) from a different location. Here we document the near-atomic- to nano-scale transformations induced by, and taking place within, AECs of three distinct amphiboles (anthophyllite, grunerite, “amosite”) with different Fe-content and morphologic features. We show that: (i) an Fe-rich layer is formed on the internalized particles, (ii) particle grain boundaries are transformed abiotically by the internal chemical environment of AECs and/or by a biologically induced mineralization mechanism, (iii) the Fe-rich material produced on the particle surface does not contain large amounts of P, in stark contrast to extracellular ABs, and (iv) the iron in the Fe-rich layer is derived from the particle itself. Internalized particles and ABs follow two distinct formation mechanisms reaching different physicochemical end-states.
Ključne besede: amphiboles, human alveolar epithelial cells, asbestos, lung cancer, nanoscale investigation, acS/TEM-EDXS, dual-EELS, asbestos-related tumors
Objavljeno v DiRROS: 16.07.2024; Ogledov: 25; Prenosov: 6
.pdf Celotno besedilo (4,53 MB)
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Diketopyrrolopyrrole pigment core@multi-layer ▫$SiO_2$▫ shell with improved photochemical stability
Erika Švara Fabjan, Zineb Saghi, Paul A. Midgley, Mojca Otoničar, Goran Dražić, Miran Gaberšček, Andrijana Sever Škapin, 2018, izvirni znanstveni članek

Povzetek: A model organic pigment (diketopyrrolopyrrole) is encapsulated by a silica coating in order to improve its photochemical stability. Unlike in previous works where single-layer silica coatings were used for similar purposes, we here propose creation of a multi-layer silica shell synthesized via in-situ sol-gel method, which should significantly improve the homogeneity and thus the protection ability of the coating. This is done by repeating the basic two-step process (pigment surface modification and silica encapsulation) several times, creating the final protective shell in a layer-by-layer fashion. The compositional and structural properties of the prepared coatings is studied using Fourier-transform infrared spectroscopy, differential thermal and thermogravimetric analysis, nitrogen adsorption measurements and transmission electron microscopy. Photochemical stability of non-encapsulated and encapsulated pigment particles is evaluated via the so-called fast-irradiation method. Various correlations between the essential coating properties, such as thickness, porosity, SiO2 content, and the corresponding photochemical stability of the samples are established and discussed in detail. As a whole, our results confirm the basic hypothesis, that multiple-layered silica shells show improved pigment protection ability in comparison to the single-layer coatings.
Ključne besede: organic pigments, silica coating, encapsulation, morphology, photocemical stability
Objavljeno v DiRROS: 27.03.2024; Ogledov: 363; Prenosov: 136
.pdf Celotno besedilo (1,78 MB)
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Colorimetric cutoff indication of relative humidity based on selectively functionalized mesoporous silica
Erika Švara Fabjan, Peter Nadrah, Anja Ajdovec, Matija Tomšič, Goran Dražić, Matjaž Mazaj, Nataša Zabukovec Logar, Andrijana Sever Škapin, 2020, izvirni znanstveni članek

Povzetek: We present a novel % cutoff concept of colorimetric indication of relative humidity based on dye dissolution in condensed water in capillaries of selectively functionalized mesoporours host SiO2 material. Consistently high levels of indoor air humidity induces mold and algae growth which represent a potential risks for human health and have deteriorating effect on walls as well. Simple localized humidity detection of high humidity with naked eye especially at places with low air circulation, where growth of mold usually starts first, is therefore highly desirable. The reporting dye was integrated in the non-functionalized mesoporous silica matrix with different pore diameters and selective-functionalized mesoporous silica material. After exposure to the environment of different air humidities the dye dissolved in water causing color change of adsorbent. With the use of adsorbents with different mesopore diameters high ability to tune the value of relative humidity when complete capillary condensation occurred was achieved. Materials with pore diameters of 3.0%nm, 3.5%nm and 7.0%nm exhibit gradual color change when reaching relative humidity up to 55, 79 and 88 RH% respectively. After selective methylation of the material with 7.0%nm pore diameter, non-gradual cutoff color change was achieved. Sample exhibited color change at narrow range of relative humidity (cutoff color change). Due to selective functionalized outer surface the dye dissolution occur only in condensed water in pores and therefore provide colorimetric indication only in this range. Selectively modified silica material has a great potential for a straightforward detection of high humid environment.
Ključne besede: turn-on colorimetric probe, selective functionalization, mesoporous silica, relative humidity, capillary condensation
Objavljeno v DiRROS: 05.09.2023; Ogledov: 431; Prenosov: 305
.pdf Celotno besedilo (7,18 MB)
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