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Iskalni niz: "ključne besede" (morphology) .

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1.
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: 25; Prenosov: 10
.pdf Celotno besedilo (1,78 MB)
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2.
Ornate Bairdiidae (Ostracoda) in 3 dimensions : exploring carapace morphology and pore canals of Triebelina van den Bold, 1946, Nodobairdia Kollmann, 1963 and Mirabairdia Kollmann, 1963
Marie-Béatrice Forel, Nathalie Poulet-Crovisier, Lidija Korat, Rosalie F. Maddocks, 2024, izvirni znanstveni članek

Povzetek: Marine ostracods of the family Bairdiidae Sars, 1888 have an evolutionary history starting from the Ordovician with an explosive diversification of ornate forms during the Triassic. Representatives of the family are notoriously homeomorphic, which makes their taxonomy a major challenge of modern ostracodology. Their classification has thus been problematic since the 1970s. Here we present the first CT-scan investigation of recent and fossil ornate Bairdiidae valves in order to characterize and evaluate the taxonomic significance of unexploited characters, such as pores and pore canals. Thanks to 3D tomography, we explore the distribution of pores at the surface and the pathway of pore ca- nals within the valve wall of the recent genus Triebelina van den Bold, 1946 and the Triassic genera Nodobairdia Kollmann, 1963 and Mirabairdia Kollmann, 1963. In Triebelina indopacifica van den Bold, 1946, we describe an unexpected system of double pore canals, so far unknown in ostracods. We confirm that pore systems in Triebelina have largely intramural positions. In the Triassic Bairdiidae (Nodobairdia mammilata Kollmann, 1963 and Mirabairdia pernodosa Kollmann, 1963), we recognize simple unrimmed and massively nodular pores as well as marginal pores. Lateral normal pores of the Triassic specimens appear to be mostly in intra-solum positions. Although still exploratory and at the limits of the tomographic resolution, these observations provide new evidence to reject the formerly proposed synonymy of Triassic genera with Triebelina, which obstructed the establishment of a phylogenetic classification.
Ključne besede: ostracods, ornate Bairdiidae, morphology, normal pore canals, CT-scan, 3D analysis
Objavljeno v DiRROS: 08.03.2024; Ogledov: 86; Prenosov: 71
.pdf Celotno besedilo (10,78 MB)
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3.
Pyrite with lower cubic symmetry from Lavrion, Greece
Mirjan Žorž, Panagiotis Voudouris, Branko Rieck, 2022, izvirni znanstveni članek

Povzetek: V tej študiji smo preučili morfološke, kemijske in strukturne podrobnosti tetraedrsko oblikovanih kristalov pirita iz rudnika Jean Baptiste v Lavrionu. Pirit se pojavlja v treh generacijah. Prvo predstavljajo tetraedrski levo oziroma desno sučni kristali z najnižjo kubično 23 simetrijo. V tej generaciji so dvojčki z višjo kubično m_3 in heksagonalno 6 simetrijo. Vsi kristali druge generacije so že primarno zdvojčeni do kubične_4m3 simetrije. Nekateri pa se dvojčijo še naprej dokler ne dosežejo najvišje kubične m_3m ali heksagonalne 6mm simetrije. Kristali tretje generacije neorientirano prekrivajo kristale druge generacije. Kemijska analiza potrjuje kemijsko čist pirit, monokristalna rentgenska analiza kristalov prve in druge generacije pa za pirit značilno m_3 simetrijo. Očitno je torej, da morfološke oblike posameznih kristalov in dvojčkov kažejo na to, da imajo najnižjo kubično simetrijo, česar pa strukturna analiza ne potrjuje. Ta diskrepanca je lahko posledica spremenjenih pT pogojev in posledične transformacije prvotne strukture pirita s simetrijo 23 v sekundarno strukturo z m_3 simetrijo ali pa neoptimalnih pogojev pri določitvi strukture z rentgensko difrakcijo.
Ključne besede: Lavrion, pyrite, morphology, tetrahedral crystals, twins, point group 23, crystal structure
Objavljeno v DiRROS: 26.07.2022; Ogledov: 609; Prenosov: 245
.pdf Celotno besedilo (18,77 MB)

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Different belowground responses to elevated ozone and soil water deficit in three European oak species (Quercus ilex, Q. pubescens and Q. robur)
Tanja Mrak, Ines Štraus, Tine Grebenc, Jožica Gričar, Yasutomo Hoshika, Giulia Carriero, Elena Paoletti, Hojka Kraigher, 2019, izvirni znanstveni članek

Povzetek: Effects on roots due to ozone and/or soil water deficit often occur through diminished belowground allocation of carbon. Responses of root biomass, morphology, anatomy and ectomycorrhizal communities were investigated in seedlings of three oak species: Quercus ilex L., Q. pubescens Willd. and Q. robur L., exposed to combined effects of elevated ozone (ambient air and 1.4 x ambient air) and water deficit (100% and 10% irrigation relative to field capacity) for one growing season at a free-air ozone exposure facility. Effects on root biomass were observed as general reduction in coarse root biomass by -26.8 % and in fine root biomass by -13.1 % due to water deficit. Effect on coarse root biomass was the most prominent in Q. robur (-36.3 %). Root morphological changes manifested as changes in proportions of fine root (<2 mm) diameter classes due to ozone and water deficit in Q. pubescens and due to water deficit in Q. robur. In addition, reduced fine root diameter (-8.49 %) in Q. robur was observed under water deficit. Changes in root anatomy were observed as increased vessel density (+18.5 %) due to ozone in all three species, as reduced vessel tangential diameter (-46.7 %) in Q. ilex due to interaction of ozone and water, and as generally increased bark to secondary xylem ratio (+47.0 %) due to interaction of ozone and water. Water deficit influenced occurrence of distinct growth ring boundaries in roots of Q. ilex and Q. robur. It shifted the ectomycorrhizal community towards dominance of stress-resistant species, with reduced relative abundance of Tomentella sp. 2 and increased relative abundances of Sphaerosporella brunnea and Thelephora sp. Our results provide evidence that expression of stress effects varies between root traits; therefore the combined analysis of root traits is necessary to obtain a complete picture of belowground responses.
Ključne besede: ozone, drought, fine roots, ectomycorrhiza, anatomy, morphology, plants
Objavljeno v DiRROS: 20.02.2020; Ogledov: 1945; Prenosov: 1280
.pdf Celotno besedilo (1,03 MB)
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6.
Morfološka analiza puhastega hrasta (Quercus pubescens Willd.) v Sloveniji
Mateja Jerše, Franc Batič, 2007, izvirni znanstveni članek

Povzetek: Z raziskavo smo poskusili ovrednotiti morfološke raznolikosti puhastega hrasta(Quercus pubescens Willd.) v Sloveniji. Raznolikost je posledica pestrosti rastišč in možnosti križanja z drugimi vrstami hrastov. Rezultati analize so bili dobljeni na osnovi meritev in opazovanja listov, plodov in kratkih poganjkov puhastegarasta, vzorčenih v osmih populacijah po Sloveniji. Na posamezni lokaciji je bilo izbranih do pet dreves in na posameznem drevesu nabranih do sto listov s kratkih poganjkov v osvetljenem delu krošnje. Na osebkih s plodovi so bili nabrani tudi plodovi. V laboratoriju je bilo na listih izmerjenih, ocenjenih in izračunanih 13 parametrov, na plodovih in kratkih poganjkih pa po en parameter. Uporabljene so bile deskriptivne, univariatne in multivariatne statistične metode za izvrednotenje rezultatov. Analize morfoloških parametrov so pokazale značilne razlike tako med posameznimi osebki v populacijah kot med populacijami. Ugotovljeno je bilo tudi, da vrsto Q. virgiliana (Ten.) Ten. lahko obravnavamo znotraj vrste Q. pubescens.
Ključne besede: puhasti hrast, Quercus pubescens Willd., Quercus virgiliana (Ten.), morfologija, listi, plodovi, Slovenija, oak, morphology, leaf, fruit, Slovenia
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4860; Prenosov: 2008
.pdf Celotno besedilo (857,31 KB)

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