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排序方式: 共有332条查询结果,搜索用时 15 毫秒
81.
Judit Fodor Karsten Meyer Christoph Gottschalk Rene Mamet Laszlo Kametler Johann Bauer Peter Horn Ferenc Kovacs Melinda Kovacs 《Food Additives & Contaminants》2007,24(4):416-420
There is a lack of information on the effect of swine caecal microbiota on fumonisin metabolism. In this in vitro study, the biotransformation of fumonisin B1 (FB1) by the gut microbiota of adult, healthy pigs was examined. Suspensions of caecal contents and McDougall buffer solution were incubated anaerobically with pure FB1 for 0, 12, 24, 48 and 72 h. After 48 h, the conversion of FB1 to partially hydrolysed FB1 (46%) was nearly equal to the percentage ratio of FB1, while by 72 h it was 49%. In vitro, the conversion of fumonisin B1 to aminopentol was less than 1%. The results show that the caecal microbiota are capable of transforming fumonisin B1 to the above metabolites. Further studies on FB1 metabolism in the small intestine are clearly justified. 相似文献
82.
Laszlo G. Harsing Jr. Joseph Knoll Ildiko Miklya 《International journal of molecular sciences》2022,23(15)
The trace amine-associated receptor 1 (TAAR1) is a Gs protein-coupled, intracellularly located metabotropic receptor. Trace and classic amines, amphetamines, act as agonists on TAAR1; they activate downstream signal transduction influencing neurotransmitter release via intracellular phosphorylation. Our aim was to check the effect of the catecholaminergic activity enhancer compound ((−)BPAP, (R)-(−)-1-(benzofuran-2-yl)-2-propylaminopentane) on neurotransmitter release via the TAAR1 signaling. Rat striatal slices were prepared and the resting and electrical stimulation-evoked [3H]dopamine release was measured. The releaser (±)methamphetamine evoked non-vesicular [3H]dopamine release in a TAAR1-dependent manner, whereas (−)BPAP potentiated [3H]dopamine release with vesicular origin via TAAR1 mediation. (−)BPAP did not induce non-vesicular [3H]dopamine release. N-Ethylmaleimide, which inhibits SNARE core complex disassembly, potentiated the stimulatory effect of (−)BPAP on vesicular [3H]dopamine release. Subsequent analyses indicated that the dopamine-release stimulatory effect of (−)BPAP was due to an increase in PKC-mediated phosphorylation. We have hypothesized that there are two binding sites present on TAAR1, one for the releaser and one for the enhancer compounds, and they activate different PKC-mediated phosphorylation leading to the evoking of non-vesicular and vesicular dopamine release. (−)BPAP also increased VMAT2 operation enforcing vesicular [3H]dopamine accumulation and release. Vesicular dopamine release promoted by TAAR1 evokes activation of D2 dopamine autoreceptor-mediated presynaptic feedback inhibition. In conclusion, TAAR1 possesses a triggering role in both non-vesicular and vesicular dopamine release, and the mechanism of action of (−)BPAP is linked to the activation of TAAR1 and the signal transduction attached. 相似文献
83.
Sebastian Grade Jörg Eberhard Philipp Wagener Andreas Winkel Csaba Laszlo Sajti Stephan Barcikowski Meike Stiesch 《Advanced Engineering Materials》2012,14(5):B231-B239
The inhibition of bacterial growth through effective non‐toxic antimicrobial substances is of great importance for the prevention and therapy of implant infections in various medical disciplines. For the evaluation of a therapeutic window of silver nanoparticles (AgNPs), their bactericidal properties were tested in agar composites and colloids on four medical relevant bacteria. Therefore, we produced AgNPs using high‐power nanosecond laser ablation in water showing a log‐normal particle diameter distribution centered at 17 nm. Bacteria were incubated with AgNP concentrations ranging from 5 to 70 µg · mL?1 and the growth rate was recorded. Additionally, cytotoxic effects of AgNPs on human gingival fibroblasts were examined. The experiments demonstrated that laser‐synthesized AgNPs resulted in a significant bacterial growth inhibition of more than 80% at the indicated concentrations in a solid agar model (Pseudomonas aeruginosa 10 µg · mL?1, Streptococcus salivarius 10 µg · mL?1, Escherichia coli 20 µg · mL?1, Staphylococcus aureus 70 µg · mL?1). In a planktonic bacteria model, the growth of the tested bacteria was significantly delayed by the addition of AgNPs at a concentration of 35 µg · mL?1. The cytotoxic assays showed limited adverse effects on human fibroblasts at concentrations of less than 20 µg · mL?1. The present study illustrates the strong antibacterial effects of ligand‐free, laser‐generated AgNPs that exhibit moderate cytotoxic effects, resulting in a therapeutically applicable concentration of AgNPs for medical purposes between 10 and 20 µg · mL?1. 相似文献
84.
Apostolos Mikroulis Elika Waloschkov Johan Bengzon David Woldbye Lars H. Pinborg Bo Jespersen Anna Sanchez Avila Zsofia I. Laszlo Christopher Henstridge Marco Ledri Merab Kokaia 《International journal of molecular sciences》2022,23(21)
Glial cell line-derived neurotrophic factor (GDNF) has been shown to counteract seizures when overexpressed or delivered into the brain in various animal models of epileptogenesis or chronic epilepsy. The mechanisms underlying this effect have not been investigated. We here demonstrate for the first time that GDNF enhances GABAergic inhibitory drive onto mouse pyramidal neurons by modulating postsynaptic GABAA receptors, particularly in perisomatic inhibitory synapses, by GFRα1 mediated activation of the Ret receptor pathway. Other GDNF receptors, such as NCAM or Syndecan3, are not contributing to this effect. We observed similar alterations by GDNF in human hippocampal slices resected from epilepsy patients. These data indicate that GDNF may exert its seizure-suppressant action by enhancing GABAergic inhibitory transmission in the hippocampal network, thus counteracting the increased excitability of the epileptic brain. This new knowledge can contribute to the development of novel, more precise treatment strategies based on a GDNF gene therapy approach. 相似文献
85.
Anja Keskinarkaus Sami Huttunen Antti Siipo Jukka Holappa Magda Laszlo Ilkka Juuso Eero Väyrynen Janne Heikkilä Matti Lehtihalmes Tapio Seppänen Seppo Laukka 《Multimedia Tools and Applications》2016,75(11):6321-6345
The MORE system is designed for observation and machine-aided analysis of social interaction in real life situations, such as classroom teaching scenarios and business meetings. The system utilizes a multichannel approach to collect data whereby multiple streams of data in a number of different modalities are obtained from each situation. Typically the system collects a 360-degree video and audio feed from multiple microphones set up in the space. The system includes an advanced server backend component that is capable of performing video processing, feature extraction and archiving operations on behalf of the user. The feature extraction services form a key part of the system and rely on advanced signal analysis techniques, such as speech processing, motion activity detection and facial expression recognition in order to speed up the analysis of large data sets. The provided web interface weaves the multiple streams of information together, utilizes the extracted features as metadata on the audio and video data and lets the user dive into analyzing the recorded events. The objective of the system is to facilitate easy navigation of multimodal data and enable the analysis of the recorded situations for the purposes of, for example, behavioral studies, teacher training and business development. A further unique feature of the system is its low setup overhead and high portability as the lightest MORE setup only requires a laptop computer and the selected set of sensors on site. 相似文献
86.
Enzymatic glycerolysis and transesterification of vegetable oil for enhanced production of feruloylated glycerols 总被引:2,自引:0,他引:2
Novel functional groups can be introduced into vegetable oils using enzymes, resulting in value-added products. The transesterification
kinetics of ethyl ferulate with MAG, DAG, and TAG were examined. Transesterification was catalyzed by immobilized Candida antarctica lipase B in solventless batch and packed-bed reactors. Initial reaction rates with TAG were slightly sensitive to water activity,
whereas rates with MAG and DAG were water activity independent. Transesterification was also three-to sixfold faster with
MAG and DAG. These observations indicate that the reaction is rate limited by the acyl acceptor, and that oils with free hydroxyl
groups are preferred acyl acceptors in comparison with TAG, which must undergo partial hydrolysis before becoming reactive. 相似文献
87.
Manel Rodríguez Ripoll Bernhard Scheichl Balázs Jakab Friedrich Franek 《Tribology Letters》2013,51(2):199-205
Doctor blades are commonly used in paper machines to keep the surface of rollers clean. Due to higher demanding conditions, the requirements for doctor blades have steadily increased. The wear rates must remain low, while simultaneously their cleaning function has to be ensured. For this reason, the paper industry has developed a high degree of empirical knowledge concerning the cleaning of roller surfaces. However, up to now, no systematic approach has been successfully applied to optimize the cleaning performance of the doctor blade-roller tribosystem. This study presents an attempt to model the system based on the force equilibrium conditions at the blade tip between hydrodynamic and contact forces. The change of the blade geometry due to wear is also taken into account. By these means, a non-dimensional group involving the key parameters is obtained. This allows for a systematic improvement of the cleaning efficiency, by targeted changes of the process parameters. 相似文献
88.
Toka Laszlo Zubor Marton Korosi Attila Darzanos George Rottenstreich Ori Sonkoly Balazs 《Telecommunication Systems》2021,76(2):219-232
Telecommunication Systems - Future online services will be provisioned over the federation of infrastructure providers for economic reasons: for effective usage of resources and for a wide... 相似文献
89.
Kara Peter A. Cserkaszky Aron Martini Maria G. Bokor Laszlo Simon Aniko 《Cognition, Technology & Work》2020,22(3):585-601
Cognition, Technology & Work - At the time of this paper, high dynamic range (HDR) visualization has already emerged in both the industry and the commercial sector, with HDR displays already... 相似文献
90.
Direct analysis in real time (DART) is a recently developed ambient ionization technique for mass spectrometry to enable rapid and sensitive analyses with little or no sample preparation. After swab-based field sampling, the organothiophosphate malathion was analyzed using DART-Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Mass resolution was documented to be over 800,000 in full-scan MS mode and over 1,000,000 for an MS/MS product ion produced by collision-induced dissociation of the protonated analyte. Mass measurement accuracy below 1 ppm was obtained for all DART-generated ions that belonged to the test compound in the mass spectra acquired using only external mass calibration. This high mass measurement accuracy, achievable at present only through FTMS, was required for unequivocal identification of the corresponding molecular formulae. 相似文献