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46 results on '"Zawadzki, Janusz"'

3. Biotechnological Potential of the Stress Response and Plant Cell Death Regulators Proteins in the Biofuel Industry

Author

Bernacki, Maciej Jerzy, primary, Mielecki, Jakub, additional, Antczak, Andrzej, additional, Drożdżek, Michał, additional, Witoń, Damian, additional, Dąbrowska-Bronk, Joanna, additional, Gawroński, Piotr, additional, Burdiak, Paweł, additional, Marchwicka, Monika, additional, Rusaczonek, Anna, additional, Dąbkowska-Susfał, Katarzyna, additional, Strobel, Wacław Roman, additional, Mellerowicz, Ewa J., additional, Zawadzki, Janusz, additional, Szechyńska-Hebda, Magdalena, additional, and Karpiński, Stanisław, additional

Published
2023
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5. The Effect of Ethanol Extracts and Essential Oils Obtained from Different Varieties of Mint on Wood Molding.

Author

Betlej, Izabela, Andres, Bogusław, Krajewski, Krzysztof, Kiełtyka-Dadasiewicz, Anna, Boruszewski, Piotr, Szadkowska, Dominika, Zawadzki, Janusz, Radomski, Andrzej, and Borysiuk, Piotr

Subjects
ESSENTIAL oils, WOOD, ETHANOL, SPEARMINT, MINTS (Plants), MALTOSE, TERPENES, INHIBITION (Chemistry)
Abstract

This paper presents the results of research on the effect of essential oils and ethanol extracts on the growth of mold fungi on Scots pine (Pinus sylvestris L.) wood. The analysis of fungal growth on the microbial medium showed that the degree of inhibition of microorganism growth depends on the amount of the extract added to the medium. At the same time, it was found that the highest dose of the extract, amounting to 5.0 cm3, almost completely inhibited the growth of fungi. In addition, it was found that mint ethanol extracts, the application of which in the wood is at least 40 g/m2, have a fungistatic effect at the initial stage of fungal development. Solutions of essential oils turned out to be more active against fungi, although also in this case the desired biocidal effect was not achieved. Essential oils significantly slowed down the growth of the fungus Ch. globosum, with the strongest fungistatic effect found for 'Morocco' spearmint oil (Mentha spicata L.). Despite the fact that in tests on agar-maltose medium, the strongest biocidal activity against Ch. globosum was found for spearmint 'Crispa' (Mentha spicata L.) oil, the effect of growth inhibition was not so clearly visible in studies on wood. Essential oils applied to the surface of the wood slowed down the growth of T. viride fungus, but not to the extent that it was found in the case of Ch. globosum. The qualitative and quantitative composition of substances belonging to the group of terpenes and their derivatives was characterized using the GCMS technique. It was shown that the ethanol extracts of mints were dominated by substances belonging to the oxygen-containing monoterpenoid and monoterpene groups. In terms of quality, the composition of essential oils turned out to be richer. [ABSTRACT FROM AUTHOR]

Published
2023
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21. Porównanie składu chemicznego kory szybko rosnącej topoli z korą innych gatunków drzew liściastych

Author

Krutul, Donata, Antczak, Andrzej, Radomski, Andrzej, Wójcik, Roman, Drożdżek, Michał, and Zawadzki, Janusz

Subjects
bark, soluble substances in 1% NaOH, extractives, fungi, mineral substances, food and beverages, lignin, complex mixtures, cellulose
Abstract

The aim of the study was to compare the content of some chemical substances in a bark of about 3−year−old fast−growing poplars Populus deltoides × maximowiczii and Populus trichocarpa with literature data on the chemical composition of a bark of older deciduous trees. The Populus deltoides × maximowiczii and Populus trichocarpa material were obtained from the Wolica experimental field belonging to the Institute of Biology, Department of Genetics, Plant Breeding and Biotechnology at Warsaw University of Life Sciences. Using the standard laboratory procedures, the chemical composition of the bark was examined, i.e. the content of extractives and mineral substances, cellulose, lignin and the content of soluble substances in 1% NaOH. The cellulose content in the bark of the 3−year−old poplars tested was higher by from 10 to 23% in relation to its content in the bark of older trees. Whereas, the content of lignin in the bark of the 3−year−old poplars was lower by from 10 to 20% compared to its content in the bark of other older trees. It was found that based on the data obtained, it is difficult to clearly determine which of the generally accepted factors affect the content of mineral substances and substances soluble in 1% NaOH in the bark. However, the content of extractives soluble in a mixture of ethanol and benzene (1:1) w/w, chloroform and ethanol (93:7) w/w as well as cellulose and lignin in the bark depends on the species, age, habitat conditions of the trees and the height of the trunk from which the samples were collected., Sylwan 164 (9): 767-774

Published
2020
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40. THE INFLUENCE OF HEAT TREATMENT ON THE PHYSICO-CHEMICAL PROPERTIES OF PINEWOOD (PINUS SYLVESTRIS L.).

Author

ZAWADZKI, Janusz, GAWRON, Jakub, ANTCZAK, Andrzej, KŁOSIŃSKA, Teresa, and RADOMSKI, Andrzej

Subjects
*PINE, *HEAT treatment, *CELLULOSE
Abstract

Pine-wood (Pinus sylvestris L.) was thermally modified at temperatures of 160°C and 200°C for 2, 6 and 10 hour periods, respectively. The severe conditions of the heat treatment resulted in decreased mechanical properties (compressive strength and modulus of elasticity) and a decrease in the degree of cellulose polymerization. A comparison of selected mechanical properties and the degree of cellulose polymerization indicated that there was a relationship between them and the temperature and duration of the heat treatment. [ABSTRACT FROM AUTHOR]

Published
2016
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41. THERMAL AGEING OF CELLULOSE WITH NATURAL AND SYNTHETIC ANTIOXIDANTS UNDER VARIOUS CONDITIONS.

Author

ANTCZAK, Andrzej, RADOMSKI, Andrzej, DROŻDŻEK, Michal, ZAWADZKI, Janusz, and ZIELENKIEWICZ, Tomasz

Subjects
AGING in plants, TREE growth, BIODEGRADATION, CELLULOSE
Abstract

Studies were undertaken of the influence of both the natural stabilizers present in wood (lignin and extractives) and synthetic antioxidants on the thermal ageing of cellulose. Among the synthetic antioxidants, butylated hydroxytoluene, propyl gallate and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline (ethoxyquin) were examined. In order to study the thermal ageing of cellulose with antioxidants, accelerated ageing tests were carried out under various conditions. The ageing tests were performed at a temperature of 95 °C in an air and nitrogen atmosphere in anhydrous conditions and at 65% relative air humidity. To study the degradation of the cellulose, size exclusion chromatography was used. The results revealed that ethoxyquin was the best synthetic stabilizer. In addition, butylated hydroxytoluene had stabilizing properties and slowed down the depolymerisation of the cellulose. In turn, the behaviour of the propyl gallate under elevated temperature conditions was the most interesting. This antioxidant, relating to the cellulose degradation process, showed inhibitory as well as catalytic properties under specific conditions. In the ageing conditions applied, the smallest decrease was observed in the average molar mass of the cellulose in the wood without extractives. The results indicate that in this case, lignin played a very important role as a hidden antioxidant. In the presence of the lignin, oxidative the cellulose depolymerisation process proceeded more slowly than with the participation of synthetic antioxidants. The extractives, under elevated temperature conditions, did not show stabilizing properties, and furthermore, they accelerated the degradation of the cellulose. [ABSTRACT FROM AUTHOR]

Published
2016
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45. An attempt to study ionizing radiation fronts in Cs vapour

Author

Zawadzki, Janusz Andrew

Abstract

Criteria are developed for the design of an experiment to study steady radiation fronts in Cs vapor. According to these criteria, a pulsed light source of supposedly sufficient intensity (≃10²²photons/cm²-sec) and pulse length (≃90ys) was built, and an absorption tube for Cs vapor inside an oven was developed (through several models) which produced a maximum absorber density of ≃10¹⁸particles/cm³. Light and electrical probe measurements were carried out to detect ionizing radiation fronts in the cesium. While the light measurements were inconclusive due to stray light problems, the probe measurements showed that photoionization takes place but at a much lower rate than expected. A subsequent study of the light source confirmed that indeed the light source, a constricted capillary arc, driven by a 90μs square current pulse, has a much lower intensity in the test section of the absorption tube than is required to drive a front. The low intensity of this light pulse rendered the initial aim of the experiment namely the study of steady ionization fronts in cesium vapor, unattainable with the available apparatus.

Published
1973
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