Determination of chemical composition and antimicrobial, antioxidant and cytotoxic activities of lichens Parmelia conspersa and Parmelia perlata

Author(s):  
Nedeljko T. Manojlović ◽  
Aleksandar B. Rančić ◽  
Rachel Décor ◽  
Perica Vasiljević ◽  
Jovica Tomović
2013 ◽  
Vol 57 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Renata Markiewicz-Żukowska ◽  
Sylwia K. Naliwajko ◽  
Emilia Bartosiuk ◽  
Justyna Moskwa ◽  
Valery Isidorov ◽  
...  

Abstract Beebread is processed pollen stored in the cells of the honeycomb, with the addition of various enzymes and honey, which undergoes lactic acid fermentation. Ethanolic extracts (EBBs) were obtained from three different samples of beebread from Poland. Assays were carried out for the determination of chemical composition (GC/MS), for the total phenolic content, and for the antioxidant and cytotoxic activities. The effects of beebread extracts (10, 20, 30, 50, 100 μg/mL) on the viability of the glioblastoma cell line (U87MG) were studied after 24 h, 48 h, and 72 h. Our results indicated a time-dependent inhibitory effect on the viability of U87MG cells treated EBB. The main inhibitory effect of EBB was observed after 72 h; EBB treatment decreased cell viability to 49 - 66%.


1988 ◽  
Vol 53 (8) ◽  
pp. 1735-1744 ◽  
Author(s):  
Jitka Horská ◽  
Jaroslav Stejskal ◽  
Pavel Kratochvíl ◽  
Aubrey D. Jenkins ◽  
Eugenia Tsartolia ◽  
...  

An attempt was made to prepare well-defined graft copolymers by the coupling reaction between acyl chloride groups located along the backbone chain and monohydroxy-terminated grafts prepared separately. The molecular weights and the parameters of heterogeneity in chemical composition of the products were determined by light scattering and osmometry. The determination of molecular characteristics revealed that the degree of grafting was low. The results therefore could not be confronted with a statistical model at this stage. The problems encountered in the synthesis, e.g., gel formation, and the data relating to the soluble products are discussed.


2015 ◽  
Vol 754-755 ◽  
pp. 1017-1022 ◽  
Author(s):  
Petrică Vizureanu ◽  
Mirabela Georgiana Minciună ◽  
Dragoş Cristian Achiţei ◽  
Andrei Victor Sandu ◽  
Kamarudin Hussin

.The paper present aspects about the obtaining of non-precious dental alloys (type CoCrMo and CoCrMoSi7), the determination of chemical composition by optical emission spectrometry and the experimental tests for determining the tensile strength, made on standard plate samples. The base material used in experiments was a commercial alloy, from CoCrMo system, which belongs to the class of dental non-precious alloys, intended to medical applications. The obtaining of studied alloy was made on arc re-melting installation, under vacuum, type MRF ABJ 900. The process followed to realize a rapid melting, with a maximum admissible current intensity. The samples for tests were obtained by casting in an electric arc furnace, under vacuum, in optimal conditions for melting and solidification and processing by electro-erosion, to eliminate all the disturbing factors which come by processing conditions for the samples. The determination of chemical composition for cobalt based alloys, by optical emission spectrometry, was made on SpectromaxX equipment with spark. The electrical discharge is made with the elimination of an energy quantity, fact which determine plasma forming and light issue. Tensile tests for standard samples, made from cobalt based alloy, was made on Instron 3382 testing machine, and assisted by computer. The obtained results are: elongation, elasticity modulus, tensile strength and offer complete information about the analyzed mechanical properties. For the certitude of obtained experimental results, the tests were made on samples with specific dimensions according ISO 6892-1:2009(E) standard, both for the tensile strength, and also machine operation.


2015 ◽  
Vol 669 ◽  
pp. 150-157
Author(s):  
Peter Michal ◽  
Alena Vagaská ◽  
Miroslav Gombár

Paper tracks experimentally confirmed relationship between chemical composition of electrolyte and resulting surface finish quality of created oxide layer during the process of anodic oxidation of aluminium. Examined chemical factors were: concentrations of sulphuric acid, oxalic acid, boric acid and sodium chloride. Aggressive effects of electrolyte were chosen as indicator of resulting layer quality – presence and extent of etching of used substrate sample.


2014 ◽  
Author(s):  
Łukasz Łazarek ◽  
Arkadiusz J. Antończak ◽  
Michał R. Wójcik ◽  
Paweł E. Kozioł ◽  
Bogusz Stępak ◽  
...  

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