41 research outputs found
Development of Fourier Transform InfraRed Spectroscopy in High Magnetic Fields
No full textInfračervená spektroskopie s Fourierovou transformací (FTIR) v silných magnetických polích, zkráceně FTIR magnetospektroskopie, je výkonná spektroskopická technika používaná ke zkoumání mnoha důležitých jevů v materiálech, např. elektronové paramagnetické rezonance, cyklotronové rezonance a přechodů mezi Landauovými hladinami. Navzdory svému obrovskému potenciálu ve fyzice pevných látek jsou infračervené magnetospektrometry stále poměrně vzácné a vyráběné na zakázku, protože takové systémy obvykle vyžadují složitou infrastrukturu. Tato disertační práce podrobně popisuje návrh a realizaci univerzálního FTIR magnetospektroskopického zařízení pracujícího v rozsahu 50 – 10 000 cm-1, silném magnetickém poli až 16 T a teplotách mezi 2 – 320 K umístěné na Středoevropském technologickém institutu VUT v Brně. Toto zařízení nám umožňuje provádět různá magnetooptická měření v rozsahu od THz/vzdálené infračervené oblasti (FIR) až po blízkou infračervenou oblast (NIR). Skládá se z komerčního FTIR spektrometru spojeného s 16 T bezkryogenním supravodivým magnetem pomocí na míru navržené optické spojky a přenosových sond určených pro experimenty s více detektory a vzorky ve Faradayově geometrii. Novinka tohoto uspořádání spočívá v použití supravodivého magnetu bez kryogenu. Optimalizovali jsme a otestovali výkonnost FTIR magnetospektroskopického zařízení pro různé konfigurace a určili použitelný rozsah zařízení. Funkčnost FTIR magnetospektroskopického zařízení byla prokázána magnetooptickými měřeními štěpení při nulovém poli v jednoiontovém magnetu na bázi kobaltu(II) v oblasti FIR, nepřímých mezipásmových přechodů mezi Landauovými hladinami (LLs) v germániu v NIR oblasti a mezipásmových přechodů mezi LLs v grafenu v oblasti FIR. Kromě toho jsme změřili volt-ampérové charakteristiky grafenových bolometrických zařízení
The antifungal activity of essential oils in combination with warm air flow against postharvest phytopathogenic fungi in apples
No full textEssential oils (EOs) are strong plant-derived antimicrobials. For their efficient use in the agri-food industry, the problems with technology of their application have to be solved. In vitro antifungal activity of cinnamon, oregano, lemongrass and clove essential oils (EOs) was tested by innovative method using EO in combination with warm air flow (WAF). EOs in concentrations from 0.25 to 512 mL/L of air were tested against eleven phytopathogenic fungi. Application of EOs in concentration of 4 and 16 mL/L by WAF method was used for treatment of apples inoculated with Penicillium expansum. Detailed sensory analysis of treated apples was performed. The WAF was more effective compare to standard disc volatilization method (DVM), the average minimum inhibitory concentrations in vitro were 5.6 mL/L during 5 min WAF treatment, compared to 136 mL/L during the DVM 24 h treatment. EOs applied by WAF delayed the incidence and development of P. expansum on apples with minimal adverse effect on their sensory profile. The WAF treatment could be considered for the development of antifungal treatments in the agrifood industry.This study was supported by the European Social Fund in the Czech Republic - project CZ.1.07/2.3.00/30.0040 (Postdok CZU), and by Ministry of Education, Youth and Sports of the Czech Republic, project No. LD13013, and CULS Internal Grant Agency (CIGA 20162004). The author wish to thank Beth Green for the proofread.Frankova, A.; Smid, J.; Bernardos Bau, A.; Finkousova, A.; Marsik, P.; Novotny, D.; Legarová, V.... (2016). The antifungal activity of essential oils in combination with warm air flow against postharvest phytopathogenic fungi in apples. Food Control. 68:62-68. https://doi.org/10.1016/j.foodcont.2016.03.024S62686
Regulation of tissue differentiation by plant growth regulators on tTCLs of Panax ginseng adventitious roots
No full text
In Vitro Antibacterial Effect of the Methanolic Extract of the Korean Soybean Fermented Product Doenjang against <i>Staphylococcus aureus</i>
No full textUltra-high performance liquid chromatography/mass spectrometry showed soyasaponin I and the isoflavones daidzein, genistein, and glycitein to be the main components of the methanolic extract of the Korean soybean fermented product doenjang, which is known to be a rich source of naturally occurring bioactive substances, at average contents of 515.40, 236.30, 131.23, and 29.00 ng/mg, respectively. The antimicrobial activity of the methanolic extract of doenjang against nine Staphylococcusaureus strains was determined in vitro by the broth microdilution method to investigate its potential to serve as an alternative antibacterial compound. The results suggest that the extract is an effective antistaphylococcal agent at concentrations of 2048–4096 µg/mL. Moreover, the tested extract also showed the ability to inhibit the growth of both methicillin-sensitive and methicillin-resistant animal and clinical S. aureus isolates. The growth kinetics of the chosen strains of S. aureus at the minimum inhibitory concentration of the methanolic extract of doenjang support the idea that the tested extract acts as an antibacterial compound. To the best of our knowledge, this is the first report on the antistaphylococcal action of the methanolic extract of doenjang thus, additional studies including in vivo testing are necessary to confirm this hypothesis
Effect of apple extracts and selective polyphenols on the adhesion of potential probiotic strains of Lactobacillus gasseri R and Lactobacillus casei FMP
No full textToxicity Assessment and Treatment Options of Diclofenac and Triclosan Dissolved in Water
No full textThe presence of pharmaceutical and personal care products in water is increasing tremendously nowadays. Typical representatives are diclofenac (DCF) and triclosan (TCS). Acute toxicity of these substances was experimentally assessed using the freshwater algae Raphidocelis subcapitata (living, immobilized). The IC(50) achieved for R. subcapitata was 177.7–189.1 mg·L(−1) for DCF and 5.4–17.2 µg·L(−1) for TCS, whereas, regarding DCF, the results corresponded to the values observed by other authors. Concerning TCS, the results were lower than predicted and indicated TCSs’ higher toxicity. The immobilized R. subcapitata showed comparable results with its living culture for DCF only. Regarding K(2)Cr(2)O(7) and TCS, the immobilized alga was more sensitive. The DCF and TCF removal from water was tested by sorption, photocatalytic and photolytic processes. TiO(2) was used as a photocatalyst. Norit and SuperSorbon were used as sorbents based on activated charcoal. The DCF decomposition achieved by both photo-processes was very fast. The starting concentration fell below the detection limit in less than one minute, while bioluminescence on Aliivibrio fischeri showed no toxic intermediates formed only in the case of photocatalysis. DCF and TCS removals by sorption were significantly faster on Norit than SuperSorbon, while the bioluminescence inhibition remained insignificant
Chemical characterization and encapsulation of <i>Ganoderma pfeifferi</i> extract with cytotoxic properties
No full text[EN] Mushrooms of the genus Ganoderma are known for diverse biological activities, demonstrated both traditionally and experimentally. Their secondary metabolites have shown cytotoxic potential across different cancer cell lines. Besides exploration of the most active components in different species or genotypes, new formulation techniques are in development. In recent years, there has been a growing interest in the use of nanomaterials because of significant potential for pharmacology applications as substance carriers. Applying nanoparticles may enhance the medicinal effect of the mushroom substances. This study investigated the cytotoxic properties of Ganoderma species methanolic extracts against the HeLa cancer cell line. Notably, the extract obtained from Ganoderma pfeifferi demonstrated the highest activity and was further used for encapsulation within synthesized mesoporous silica nanoparticles MCM-41. Subsequently, the cytotoxic effect of the loaded MCM-41 to the free form of extract was compared. The obtained results indicate successful encapsulation, and similar activity comparing encapsulated form to free extracts (IC50 16.6 mu g/mL and 20.5 mu g/mL, respectively). In addition, the four unique compounds were identified as applanoxidic acid A, applanoxidic acid G, ganoderone A, and ganoderone B in the G. pfeifferi. This study is an essential prerequisite for further steps like nanoparticle functionalization for sustained or on-command delivery of these natural extracts.The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This work was funded by the National Agency for Agricultural Research of the Ministry of Agriculture of the Czech Republic under project number QK1910209; by the Research Infrastructure METROFOOD-CZ supported by the Ministry of Education, Youth, and Sports of the Czech Republic under project number LM2023064). This research was supported by projects PID 2021-126304OB-C41 and PID 2021- 128141OB-C22 funded by MCIN/AEI/10.13039/501100011033/and by European Regional Development Fund- A way of doing Europe. This study was also supported by Generalitat Valenciana (CIPROM/2021/007). This research was supported by CIBER-Consorcio Centro de Investigacion Biomedica en Red- (CB06/01/2012), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovacion. A.M.-A. thanks to the Universitat Politecnica de Valencia (UPV) for her Ph.D. grant (DOCEMPR22). AB. thanks the MCIN for her BG20/00020 contract.Stastny, J.;Morella-Aucejo, Á.;Skala, T.;Bernardos Bau, A.;Marsik, P.;Lerida-Viso, A.;Matejka, J.... (2025). Chemical characterization and encapsulation of Ganoderma pfeifferi extract with cytotoxic properties. Frontiers in Pharmacology. 16. https://doi.org/10.3389/fphar.2025.1526502S1
X-ray imaging with compound refractive lens and microfocus X-ray tube
No full textCompound refractive lenses (CRL), consisting of a lot number in-line concave microlenses made of low-Z material were studied. Lenses with focal length 109 mm and 41 mm for 8-keV X-rays, microfocus X-ray tube and X-ray CCD camera were used in experiments. Obtained images show intensity distribution of magnified microfocus X-ray source focal spot. Within the experiments, one lens was also used as an objective lens of the X-ray microscope, where the copper anode X-ray microfocus tube served as a source. Magnified images of gold mesh with 5 microns bars were obtained. Theoretical limits of CRL and experimental results are discussed
X-ray imaging with compound refractive lens and microfocus X-ray tube
No full textCompound refractive lenses (CRL), consisting of a lot number in-line concave microlenses made of low-Z material were studied. Lenses with focal length 109 mm and 41 mm for 8-keV X-rays, microfocus X-ray tube and X-ray CCD camera were used in experiments. Obtained images show intensity distribution of magnified microfocus X-ray source focal spot. Within the experiments, one lens was also used as an objective lens of the X-ray microscope, where the copper anode X-ray microfocus tube served as a source. Magnified images of gold mesh with 5 microns bars were obtained. Theoretical limits of CRL and experimental results are discussed
