Characterisation of a prehistorical ceramic object

Archaeological ceramics findings are usually characterised by a combination of methods to provide as many as possible information about their origin, use and deposition. Unique moon-shaped idol approximately 0.5 m long from the Final Bronze Age was studied by XRD, XRF, Raman spectroscopy and thermal analyses (TG, DTA, DSC). Special attention was given to processes occurring during its thermal treatment, which were specified by thermal analysis. It was proved that the process of kaolinite dehydroxylation proceeded less intensively in the central part of the object and the maximum of peak was shifted to lower temperature compared to the border parts. It is supposed that the moon-shaped idol was thermally treated not until its use, and the border parts of the object were exposed to lower temperatures compared to the central part.     

Synthesis and study of mixed oxide inorganic pigment from Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>–ZnO–CeO<Subscript>2</Subscript> system

Novel environment-friendly yellow mixed oxide inorganic pigment from Bi₂O₃–ZnO–CeO₂ system with the composition 23 mol% Bi₂O₃, 15 mol% ZnO and 62 mol% CeO₂ was successfully synthesized by a conventional solid-state reaction method. Comprehensive analyses were carried out to characterize the develop pigment powder including simultaneous TG–DTA thermal analysis, colour properties and particle size distribution. The results demonstrated that the optimum calcination for pigment synthesis was located at a range 800–950 °C. The colour of the studied mixed oxide pigment is connected with the calcination condition. The substitution of Zn²⁺ changes the colour from orange to yellow. The colour of the obtained samples was dependent on the calcination condition and the particle size distribution. The most saturated yellow hue was obtained at the calcination temperature of 950 °C for 2 h in a furnace of pure air and after its application into organic binder in mass tone. The value C of this sample was approx. 65. The mixed oxide pigments were also evaluated from the standpoint of their particle size distribution. Bi₂Ce₂O₇ is considered to be a non-toxic compound, and the other component (Zn²⁺ ions) is also the safe element. Therefore, the present mixed oxide could be an attractive candidate as a novel environment-friendly inorganic yellow pigment.     

Success and failure of the Chemical Leasing model in addressing sustainability challenges: Evidence from practice

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Newly synthesized indolizine derivatives — antimicrobial and antimutagenic properties

A series of indolizine derivatives have been synthesized and subjected to antibacterial screening studies. Antibacterial activity of 21 derivatives was investigated against Staphylococcus aureus, Mycobacterium smegmatis, Salmonella typhimurium and Escherichia coli; also, the sensitivity of model yeast Candida parapsilosis and some model filamentous fungi Aspergillus fumigatus, Alternaria alternata, Botrytis cinerea and Microsporum gypseum was tested. Newly synthesized indolizine derivatives have shown selective toxicity to Gram-positive bacteria S. aureus and were also considered to be able to inhibit the acidoresistant rod M. smegmatis. Derivative XXI has shown the highest inhibition effect with the bacteriostatic effect on the cells at the concentration of 25 µg mL^?1. The best antifungal activity has been detected in the presence of derivative XIII. Derivative XIII did also affect the morphology of hyphal tips of B. cinerea, which led to enhanced ramification of hyphae. Finally, the antimutagenic activity of derivatives was investigated. Significant antimutagenic activity was registered in case of derivative VIII. The number of induced revertants by mutagen [2-(5-nitrofuryl)acrylic acid] was decreased almost to the level of spontaneous revertants in the lowest applied concentration (50 µg per plate).     

In‐Situ Spin Labeling of His‐Tagged Proteins: Distance Measurements under In‐Cell Conditions

New spin labeling strategies have immense potential in studying protein structure and dynamics under physiological conditions with electron paramagnetic resonance (EPR) spectroscopy. Here, a new spin‐labeled chemical recognition unit for switchable and concomitantly high affinity binding to His‐tagged proteins was synthesized. In combination with an orthogonal site‐directed spin label, this novel spin probe, Proxyl‐trisNTA (P‐trisNTA) allows the extraction of structural constraints within proteins and macromolecular complexes by EPR. By using the multisubunit maltose import system of E. coli: 1) the topology of the substrate‐binding protein, 2) its substrate‐dependent conformational change, and 3) the formation of the membrane multiprotein complex can be extracted. Notably, the same distance information was retrieved both in vitro and in situ allowing for site‐specific spin labeling in cell lysates under in‐cell conditions. This approach will open new avenues towards in‐cell EPR.     

Surface structure and reactivity study of phosphotungstic acid-nitrogenated ormosils

Supramolecular interactions between nitrogenated groups in hybrid ormosils bearing phosphotungstate nanocatalyst were used to tune the photocatalytical activity of these class-II hybrid materials obtained through sol–gel chemistry. Surface chemistry and morphology of the materials was studied by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and water contact angle measurements. The photocatalytic efficiency of these hybrid films, measured by the degradation of crystal violet over-layer deposited on ormosils films, is higher for ormosils bearing neutral, more polar and less H-bonding nitrile groups than those bearing alkylamine/alkylammonium functionalities, despite the lower W/Si atomic ratio on the surface and lower tungsten percentage of the pure nitrile bearing ormosils. Such higher surface reactivity of the nitrile bearing ormosils is due to weaker interaction with the phosphotungstate and the lower activity of amine bearing ormosils is attributed to the competition among reversible photochromism and photocatalysis pathways in these materials.     

Automatic identification of novel bacteria using Raman spectroscopy and Gaussian processes

Raman spectroscopy is successfully used for the reliable classification of complex biological samples. Much effort concentrates on the accurate prediction of known categories for highly relevant tasks in a wide area of applications such as cancer detection and bacteria recognition. However, the resulting recognition systems cannot always be directly used in practice since unseen samples might not belong to classes present in the training set. Our work aims to tackle this problem of novelty detection using a recently proposed approach based on Gaussian processes. By learning novelty scores for a large bacteria Raman dataset comprising 50 different strains, we analyze the behavior of this method on an independent dataset which includes known as well as unknown categories. Our experiment reveals that non-parametric methods such as Gaussian processes can be successfully applied to the task of finding unknown bacterial strains, leading to encouraging results motivating their further utilization in this area.