Search results for "ISMU"
showing 10 items of 685 documents
Glimmering utopias: 50 years of African film
2010
The history of African film began in the 1960s with the independence of the colonies. Despite all kinds of political and economic difficulties, numerous films have been made since then, featuring wide-ranging processes of consolidation, differentiation and transformation which were characteristic of post-colonial sub-Saharan Africa. However, these feature films should not merely be viewed as back references to specifically African problems. The glimmering fictions are imagination spaces. They preserve ideas about how the post-colonial circumstances should be approached. Seen from this perspective, the history of African film may be studied as a history of African utopias. Die Geschichte des…
Differences between cysteine and homocysteine in the induction of deoxyribose degradation and DNA damage.
2001
The effect of two naturally occurring thiols, such as cysteine and homocysteine, has been examined for their ability to induce deoxyribose degradation and DNA damage. Copper(II) ions have been added to incubation mixtures and oxygen consumption measurements have been performed in order to correlate the observed damaging effects with the rate of metal catalyzed thiol oxidation. Ascorbic acid plus copper has been used as a positive control of deoxyribose and DNA oxidation due to reactive oxygen species. Cysteine or homocysteine in the presence of copper ions induce the degradation of deoxyribose and the yield of 8-hydroxy-2'-deoxyguanosine (8-OHdG), although important differences are observed…
Photogenotoxicity of folic acid.
2013
Folic acid (FA), also named vitamin B9, is an essential cofactor for the synthesis of DNA bases and other biomolecules after bioactivation by dihydrofolate reductase (DHFR). FA is photoreactive and has been shown to generate DNA modifications when irradiated with UVA (360 nm) in the presence of DNA under cell-free conditions. To investigate the relevance of this reaction for cells and tissues, we irradiated three different cell lines (KB nasopharyngeal carcinoma cells, HaCaT keratinocytes, and a melanoma cell line) in the presence of FA and quantified cytotoxicity and DNA damage generation. The results indicate that FA is phototoxic and photogenotoxic by two different mechanisms. First, ext…
Iekapsulētas 15. grupas metālu halkogenīdu/oglekļa nanocaurulīšu heterostruktūras lokanu termoelektrisko materiālu izveide
2022
Iekapsulētas 15. grupas metālu halkogenīdu/oglekļa nanocaurulīšu heterostruktūras lokanu termoelektrisko materiālu izveide. Brauna L., darba vadītājs Prof., Dr. chem. Erts D., un pētnieks Mg. phys. Buks K., bakalaura darbs fizikālajā ķīmijā. 46 lappuses, 31 attēli, 12 tabulas, 32 literatūras avoti. Latviešu valodā. 15. grupas metālu halkogenīdiem ar tiem piemītošo termoelektrisko īpašību dēļ ir svarīgs pielietojums termoelektrisko ģeneratoru izveidē. Ar visā pasaulē pieaugošo interesi par elastīgām termoelektriskām ierīcēm, ir nepieciešama efektīva termoelektrisko kompozītu izstrāde. Darbā tika izveidotas oglekļa nanocaurulīšu un Bi2Se3 vai Sb2Te3 heterostruktūras, kuras mehāniski stabilu, …
Zvaigžņotā Debess: 2015, Vasara (228)
2015
Latvijas Universitāte
Circolazione e sviluppo di un modello metodologico. La critica testuale delle fonti giuridiche romane fra Otto Gradenwitz e Salvatore Riccobono
2018
La ricerca delle interpolazioni, cominciata con la Scula culta, viene ripresa in Germania alla fine del XIX secolo. Fra quanti misero a punto un metodo storico-critico per lo studio delle fonti giuridiche romane va menzionato anche Gradenwitz, che – insieme ad altri studiosi tedeschi – sarebbe stato uno dei maestri di Riccobono. La prima produzione scientifica di Riccobono, che si riconosce nel nuovo indirizzo storico-critico affermatosi in Germania, si avvale dei metodi appresi dai maestri tedeschi. Lungo questo solco, tuttavia, comincia l’elaborazione di un metodo più raffinato, che distingue fra interpolazioni formali e interpolazioni sostanziali e recupera gradualmente altri strumenti d…
Structural, vibrational and electrical study of compressed BiTeBr
2016
Compresed BiTeBr has been studied from a joint experimental and theoretical perspective. Room-temperature x-ray diffraction, Raman scattering, and transport measurements at high pressures have been performed in this layered semiconductor and interpreted with the help of ab initio calculations. A reversible first-order phase transition has been observed above 6–7 GPa, but changes in structural, vibrational, and electrical properties have also been noted near 2 GPa. Structural and vibrational changes are likely due to the hardening of interlayer forces rather than to a second-order isostructural phase transition while electrical changes are mainly attributed to changes in the electron mobilit…
Phase transitions in i-butylammonium halogenoantimonate(III) and bismuthate(III) crystals
1997
Abstract Differential scanning calorimetry, dielectric, thermal expansion, infrared and preliminary X-ray diffraction studies on i-butylammonium halogenoantimonate(III) and bismuthate(III) crystals are reported. All crystals: (i-C4H9NH3)2BiCl5, (i-C4H9NH3)2SbBr5, (i-C4H9NH3)3BiCl6, (i-C4H9NH3)3Bi2Br9, (i-C4H9NH3)3Sb2Br9, show one or more structural phase transitions of first order type. The values of the transition entropies suggest that the most of the phase transitions are of the order-disorder type. The infrared studies confirmed the contribution of the i-butylammonium cations in the phase transition mechanism.
High-pressure vibrational and optical study of Bi2Te3
2011
We report an experimental and theoretical lattice dynamics study of bismuth telluride (Bi2Te 3 )u p to 23 GPa together with an experimental and theoretical study of the optical absorption and reflection up to 10 GPa. The indirect bandgap of the low-pressure rhombohedral (R-3m) phase (α-Bi2Te 3) was observed to decrease with pressure at a rate of − 6m eV/GPa. In regard to lattice dynamics, Raman-active modes of α-Bi2Te 3 were observed up to 7.4 GPa. The pressure dependence of their frequency and width provides evidence of the presence of an electronic-topological transition around 4.0 GPa. Above 7.4 GPa a phase transition is detected to the C2/m structure. On further increasing pressure two …
Heterovalent ion replacement in bi7Ti4NbO21: Some new compounds and phase transitions
1996
Abstract Simultaneous heterovalent substitutions at two cationic sites of the bismuth mixed-layered compound Bi7Ti4NbO21 have been made. Two new compounds: Bi2Pb⅓Ti(4/3)Mo⅓O7 and Bi(4/3)PbTiMo⅔O7, were obtained and identified by X-ray diffraction analysis. A model of possible mixed layer structure is discussed. Ferroelectric phase transitions at 510°C and 550°C have been studied by dielectric measurements.