Autor: Wielgus, Agnieszka - Katalog OPAC zbiorów

Tytuł:: A simulation of thinning of microphone array in near-field broadband beamformers
Autorzy:: Wielgus, Agnieszka
Szlachetko, Bogusław
Powiązania:: https://bibliotekanauki.pl/articles/2146656.pdf
Data publikacji:: 2021
Wydawca:: Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:: acoustics
beamforming systems
microphone array
thinning technique
akustyka
beamforming
macierz mikrofonów
technika przerzedzania
Opis:: This paper is devoted to the problem of designing an optimal microphone matrix. We define a criterion function where the performance of our matrix should be as close as possible to the desired one based on L2 norm. In the classical approach, increasing a size of the matrix is used to improve the system performance. However, in many cases it is not a good solution. In this paper we propose a solution based on thinning technique. We work with rectangular, equispaced microphone matrix and using metaheuristic approach called simulated annealing we optimise the set of active microphones (we switch off some of the microphones from the regular matrix). For illustrations, few numerical examples are solved. Comparing to the classical approach we show that thinning microphone matrix can significantly improve system performance.
Źródło:: Vibrations in Physical Systems; 2021, 32, 2; art. no. 2021204
0860-6897
Pojawia się w:: Vibrations in Physical Systems
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Comparison of in vitro antioxidative activities of crude methanolic extracts of three species of Passiflora from greenhouse using DPPH, ABTS and FRAP methods
Autorzy:: Ożarowski, Marcin
Pietrowiak, Aurelia
Gryszczyńska, Agnieszka
De A.Chaves, Douglas Sigueira
Krajewska-Patan, Anna
Wielgus, Karolina
Seremak-Mrozikiewicz, Agnieszka
Powiązania:: https://bibliotekanauki.pl/articles/2048750.pdf
Data publikacji:: 2019
Wydawca:: Instytut Włókien Naturalnych i Roślin Zielarskich
Tematy:: passionflower
herbal extract
antioxidant activity
DPPH
ABTS
FRAP
phenolic compound
passiflora
ekstrakt ziołowy
aktywność antyoksydacyjna
związki fenolowe
Opis:: Introduction:. It is well documented that many species from Passifloraceae family can provide edible and nutritious fruits while the leaves of cultivated plants are renewable and waste material. This biomass may be further used in various sectors, especially as a bioactive food additive and as source of innovative pharmaceuticals, cosmetics or feed additives. The biomaterials and green chemistry are new sectors bioeconomy according to the high-level horizontal strategies and bio-based industries in Europe. In recent years, attention has been paid to the biological activity and phytochemical profiles of extracts from different species of Passiflora. However, there is little comparative studies using the same procedures and techniques in the same laboratory conditions for study of plant material obtained from the similar greenhouse conditions. Objective: This study was focused on the examination of antioxidative activities of low concentrations of crude extracts from leaves of Passiflora incarnata L., Passiflora caerulea L., and Passiflora alata Curtis. Methods: The activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging and ferric reducing antioxidant power (FRAP) methods. Results of study were supported by estimation of chemical composition with secondary metabolites profiling in extracts which were carried out previously for the same extracts from three Passiflora species. One-way ANOVA analysis revealed significant differences in the antioxidant activity of various concentrations of the extracts using the DPPH and ABTS radical models, and FRAP method. Results: Measurement of antioxidant capacity (expressed as trolox equivalent, TE) showed that the most active was extract of P. caerulea > P. alata > P. incarnata. Phytochemical analysis for extracts of P. caerulea and P. incarnata showed greater similarities in metabolites content than P. alata. However, comparative statistical analysis of antioxidant activity showed that despite this phytochemical similarities, extract from P. alata leaves had higher activities than extract from leaves P. incarnata. Antioxidant effect of extract from P. alata can be explain by terpenoids presented in this extract. In this work, there have been discussed activities against Acanthamoeba castellanii strain, antibacterial and antifungal activities against selected clinical microorganisms (Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, and Candida albicans, Microsporum gypseum), and anti-leukemic activities tested in human acute lymphoblastic leukemia cell lines for this extracts, which have been described in previous authors’ publications. Conclusion: Our current and previous studies showed that the same crude extracts from leaves of P. alata, P. caerulea, P. incarnata exerted not only antioxidant potential in vitro but also few interesting properties such as antibacterial, antifungal, amoebostatic, amoebicidal activities, which indicate the possibility of using these extracts in both a healthy diet and natural cosmetics. Leaves of this species may become an interesting source of biomaterials which can exert health-promoting effects.
Źródło:: Herba Polonica; 2019, 65, 3; 10-21
0018-0599
Pojawia się w:: Herba Polonica
Dostawca treści:: Biblioteka Nauki

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