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Antimicrobial activity of cobalt bis(dicarbollide) aminoderivatives
Kvasničková, E.; Masák, J.; Šícha, Václav
2015 - English
We carried out experiments focused on the determination of the antimicrobial acitivity of selected representatives of cobalt bis{dicarbollide) aminoderivates. lt was proved, that studied yeast strain C. parapsilosis DBM 2165 is not sensitive to the cobalt bis{dicarbollide) or its aminoderivatives. Gram-negative bacteria P. aeruginosa B-59188 is weakly susceptive to cobalt bis(dicarbollide), but no significant inhibition of growth by cobalt bis(dicarbollide) aminoderivatives was observed. The highest effect on inhibition of microbial growth was confirmed in the case of gram-positive bacteria 5. aureus. This observation demonstrates the real possibility of using these substances in the treatment of infection caused by gram-positive bacterial strains.
Keywords:
cobalt bis(dicarbollide); aminoderivatives; antimicrobial activity
Available at various institutes of the ASCR
Antimicrobial activity of cobalt bis(dicarbollide) aminoderivatives
We carried out experiments focused on the determination of the antimicrobial acitivity of selected representatives of cobalt bis{dicarbollide) aminoderivates. lt was proved, ...
Tuning the Photophysical Properties of Anti-B18H22 [1]
Braborec, Jakub; Černá, H.; Benkocká, M.; Kolská, Z.; Londesborough, Michael Geoffrey Stephen
2015 - English
The tuning of the photophysical properties of the highly fluorescent boron hydride cluster anti-B18H22 (1), by straight-forward chemical substitution to produce 4,4'-(HS)(2)-anti-B18H20 (2), facilitates intersystem crossing from excited singlet states to a triplet manifold.[1] This subsequently enhances O-2((1)Delta(g)) singlet oxygen production from a quantum yield of Phi(Delta) similar to 0.008 in 1 to 0.59 in 2. This contribution describes the synthesis and full structural characterization of the new compound 4,4'-(HS) 2-anti-B18H20 (2) and uses UV-vis spectroscopy coupled with DFT and ab initio computational studies to delineate and explain its photophysical properties. Additionally, we will report on new fluorescent derivatives of anti-B18H22 and their immobilisation on solid nanostructured substrates.
Keywords:
borane hydrides; singlet oxygen; fluorescent boranes
Available at various institutes of the ASCR
Tuning the Photophysical Properties of Anti-B18H22 [1]
The tuning of the photophysical properties of the highly fluorescent boron hydride cluster anti-B18H22 (1), by straight-forward chemical substitution to produce 4,4'-(HS)(2)-anti-B18H20 (2), ...
Investigation of Madonna in the travel altar of Robert of Anjou from the collection of moravian gallery in Brno
Fogaš, I.; Wörgötter, Z.; Hradilová, J.; Hradil, David; Zikmund, T.; Kaiser, J.
2014 - English
An exceptional Gothic work of art, a travel altar of Robert of Anjou, is one of those donated by John II of Liechtenstein to the Franz Museum in Brno in 1896. Light has been newly shed on the circumstances of Prince's acquisition of the altar; it refuted the thoughts about the altar's Central European provenance, because as it is being documented, the purchase took place directly in Florence in 1890. It has been recorded already back then that the Tabernacle is complemented by a (damaged) statuette of Black Madonna made of Carrara marble. The description of its damage, secondary additions and polychromy construction was the main aim of the artwork's survey by non-invasive methods (mobile XRF, computed tomography); on the basis of their results, a careful micro-sampling has been performed followed by material analysis. Most importantly, it was found out that the material of the statue is not Carrara marble, but an alabaster, which is not in disagreement with the assumed provenance (northern Italy), but due to its weight and fragility, the statuette could only hardly be an original part of the altar. Concurrently, the analysis of the oldest layers of polychromy proved that the Madonna has not been originally black and that this adjustment has been executed secondarily and intentionally.
Keywords:
Black Madonna; travel altar,; alabaster; Gothic art; Florence; Liechtenstein
Available at various institutes of the ASCR
Investigation of Madonna in the travel altar of Robert of Anjou from the collection of moravian gallery in Brno
An exceptional Gothic work of art, a travel altar of Robert of Anjou, is one of those donated by John II of Liechtenstein to the Franz Museum in Brno in 1896. Light has been newly shed on the ...
Anti-B18H22: A Brand-New Laser Material
Cerdán, L.; Braborec, Jakub; Garcia-Moreno, I.; Costela, A.; Londesborough, Michael Geoffrey Stephen
2014 - English
The first laser borane, anti-B18H22, exhibits blue laser emission at 406nm with an efficiency of 9.5 % and a photostability superior to that of commercial laser dyes, providing a new solution to an old problem.
Keywords:
Laser excitation; Measurement by laser beam; Chemical lasers
Available at various institutes of the ASCR
Anti-B18H22: A Brand-New Laser Material
The first laser borane, anti-B18H22, exhibits blue laser emission at 406nm with an efficiency of 9.5 % and a photostability superior to that of commercial laser dyes, providing a new solution to an ...
Signs of degradation of czech art nouveau mosaic glasses
Rohanová, D.; Švarcová, Silvie; Hájek, T.
2012 - English
Analyses of Art Nouveau mosaics from the church of St. Simon and Juda in Dolín near Slaný and from Holovousy, both most likely made by the workshop of Viktor Foerster, have shown that the author used the NaO-PbO-SiO 22 glass type and that he used the same glass also for restoration of The Last Judgment mosaic at the Prague Castle in 1890-1910. Despite the fact that lead glasses are more durable than potassium glasses, the material investigations identified corrosion processes on the surface of the glass pieces (tesserae) depending on their composition. Apart from the analyzed mosaic NaO-PbO-SiO2 glasses, we also used ancient sodium glasses (NaO-CaO-SiO2) and 22 potassium glasses (K2O-CaO-SiO2) from archaeological finds in Opava to demonstrate their different chemical durability. We also paid attention to fixation binders used in Art Nouveau mosaics. Inappropriate use of gypsum-containing binders is a significant cause of disintegration of the mosaics. Gypsum and gypsum-lime plasters are very sensitive to humidity. Capillary action of water is a very serious problem that endangers the overall lifespan of any mosaic.
Keywords:
glass mosaic; tesserae; glass corrosion; Victor Foerster; lead glass; Art Nouveau
Available at various institutes of the ASCR
Signs of degradation of czech art nouveau mosaic glasses
Analyses of Art Nouveau mosaics from the church of St. Simon and Juda in Dolín near Slaný and from Holovousy, both most likely made by the workshop of Viktor Foerster, have shown that the author used ...
The effects of artificial ageining on model colour layeres containing neutral verdigris
Bauerová, P.; Bezdička, Petr
2012 - English
Verdigris belongs to traditional painting pigments. In artworks it most often occurs in combination with lead-tin yellow or lead white. However, its colour is considered unstable. The aim of this study was to find out which conditions contribute to colour changes of the most frequently used neutral verdigris (hoganite) Cu(CH3COO)2.H2O and whether these changes happened as a result of the assumed verdigris-binder interactions or caused by the degradation of the pigment itself. The article summarises first results of artificial ageing experiments.
Keywords:
neutral verdigris; artificial ageing; colour change; degradation
Available at various institutes of the ASCR
The effects of artificial ageining on model colour layeres containing neutral verdigris
Verdigris belongs to traditional painting pigments. In artworks it most often occurs in combination with lead-tin yellow or lead white. However, its colour is considered unstable. The aim of this ...
Origin, composition and stability of copper pigments in wall paintings
Švarcová, Silvie; Bezdička, Petr; Hradil, David
2012 - English
Blue and green copper pigments occur in a wide range of chemically close, although mineralogically different species, which makes their proper identification nontrivial. Furthermore, they can be of various origins – natural, artificial or formed as a result of corrosion of another copper pigment. The degradation of copper pigments is a serious problem in case of artworks exposed to corrosive environment, such as wall paintings or exterior stone polychromes. In this paper, we document the variability of copper pigments used in history on examples of selected wall paintings. The problem of origin and stability of copper pigments in wall paintings is solved using advanced microanalytical investigation of paint layers together with the laboratory experiments. Microanalytical features documenting natural or artificial origin of copper pigments as well as their secondary changes caused by corrosive environment are shown and discussed.
Keywords:
copper pigments; wall paintings; origin; corrosion
Available at various institutes of the ASCR
Origin, composition and stability of copper pigments in wall paintings
Blue and green copper pigments occur in a wide range of chemically close, although mineralogically different species, which makes their proper identification nontrivial. Furthermore, they can be of ...
Gothic painted decorations in the Gallery of the castle in Lidzbark Warminski
Hradil, David; Hradilová, J.; Švarcová, Silvie; Bezdička, Petr; Čermáková, Zdeňka; Bartlová, M.
2012 - English
Materials research was aimed at finding specific characteristics, which could indicate the provenance of mural paintings uncovered in Bishops castle in Lidzbark Warmiński, northeast Poland. An expected relation of these murals to Bohemian artistic workshops, which were active in the 14th century at the Emperor Charles IV’s court in Prague, was supported by further exact data. The lead-tin yellow – type II was identified by X-ray microdiffraction; up to the present day, this uncommon modification of the pigment was proved solely in the Bohemian painting of the 14th century (e.g. Master of Třeboň altarpiece) and in the Italian painting of the 14th to 16th century. Nickel is an element accompanying natural iron-based pigments and was found both in the painting and the drawing, respectively. It is possible to demonstrate that this admixture indicates the source locality of the pigment in Lower Silesia, which belonged to the Kingdom of Bohemia in the 14th century and was exploited for chrysoprases – green gemstones frequently appearing in Bohemian jewellery and wall decorations (St. Wenceslas chapel in the Prague’s cathedral, Karlštejn Castle). Lidzbark murals exhibit features similar to the panel painting, e.g. the use of tempera, natural chalk in the preparatory layer, lead pigments and madder lakes in the painting. The madder was extracted from the wool fibres, which are still clearly visible in the samples.
Keywords:
Lidzbark Warmiński; Gothic mural paintings; ni-bearing laterite; chrysoprase; lead-tin yellow
Available at various institutes of the ASCR
Gothic painted decorations in the Gallery of the castle in Lidzbark Warminski
Materials research was aimed at finding specific characteristics, which could indicate the provenance of mural paintings uncovered in Bishops castle in Lidzbark Warmiński, northeast Poland. An ...
Newly Found romanesque madonna of Sedes sapientiae type coming from a czech private collection with elements of west european fine arts tradition
Hradilová, J.; Hradil, David; Fogaš, I.; Zmydlená, M.
2012 - English
On the basis of material research, the oldest preserved polychrome carving of Madonna of Sedes sapientiae type was dated using radiocarbon method 14C to the interval of 990 – 1180. During the non-destructive research, we could observe its inner structure on the CT scans and a careful sampling enabled us to determine the technological features typical for this outstanding polychromy. These features comprise, above all, the oldest siliceous ground of specific composition, which had a practical relevance. The coloured, or only coarse-grained lower ground layer, served as a check for the depth of polish of the upper white ground – the treatment, which should result in the same thickness of the ground on all places of the uneven surface. The origin of Madonna of Sedes sapientiae type can be assigned to workshops drawing on Western-European traditions.
Keywords:
madonna Sedes sapientiae; 12th century; siliceous ground; radiocarbon dating 14c
Available at various institutes of the ASCR
Newly Found romanesque madonna of Sedes sapientiae type coming from a czech private collection with elements of west european fine arts tradition
On the basis of material research, the oldest preserved polychrome carving of Madonna of Sedes sapientiae type was dated using radiocarbon method 14C to the interval of 990 – 1180. During the ...
Limitations of spectroscopic methods in the study of earthy pigments
Košařová, V.; Hradil, David; Kanický, V.
2012 - English
Nowadays, the spectroscopic methods, above all Infrared Spectroscopy (IR), are the most frequently used analytical methods in the research of cultural heritage, which is mainly caused by easy use and non-invasiveness of these methods and a broad range of their application, which comprises both organic and inorganic substances. Nevertheless, each analytical technique has its detection limits, and the fact that a particular method is suitable for one type of a sample does not automatically mean that it will be appropriate for the identification of another sample. Therefore, the aim of the study is to demonstrate the limitations of both Raman Spectroscopy (RS) and infrared spectroscopy in the study of earthy materials.
Keywords:
Raman spectroscopy; infrared spectroscopy; earthy pigment; clay minerals
Available at various institutes of the ASCR
Limitations of spectroscopic methods in the study of earthy pigments
Nowadays, the spectroscopic methods, above all Infrared Spectroscopy (IR), are the most frequently used analytical methods in the research of cultural heritage, which is mainly caused by easy use and ...
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