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91.
Jana Sedlarikova Magda Janalikova Petra Peer Lucie Pavlatkova Antonin Minarik Pavel Pleva 《International journal of molecular sciences》2022,23(1)
Zein is renewable plant protein with valuable film-forming properties that can be used as a packaging material. It is known that the addition of natural cross-linkers can enhance a film’s tensile properties. In this study, we aimed to prepare antimicrobial zein-based films enriched with monolaurin, eugenol, oregano, and thyme essential oil. Films were prepared using the solvent casting technique from ethanol solution. Their physicochemical properties were investigated using structural, morphological, and thermal techniques. Polar and dispersive components were analyzed using two models to evaluate the effects on the surface free energy values. The antimicrobial activity was proven using a disk diffusion method and the suppression of bacterial growth was confirmed via a growth kinetics study with the Gompertz function. The films’ morphological characteristics led to systems with uniform distribution of essential oils or eugenol droplets combined with a flat-plated structure of monolaurin. A unique combination of polyphenolic eugenol and amphiphilic monoglyceride provided highly stretchable films with enhanced barrier properties and efficiency against Gram-positive and Gram-negative bacteria, yeasts, and molds. The prepared zein-based films with tunable surface properties represent an alternative to non-renewable resources with a potential application as active packaging materials. 相似文献
92.
Václav Čeřovský Dr. Miloš Buděšínský Dr. Oldřich Hovorka Dr. Josef Cvačka Dr. Zdeněk Voburka Jiřina Slaninová Dr. Lenka Borovičková Vladimír Fučík Dr. Lucie Bednárová Dr. Ivan Votruba Dr. Jakub Straka 《Chembiochem : a European journal of chemical biology》2009,10(12):2089-2099
Three novel structurally related pentadecapeptides, named lasioglossins, were isolated from the venom of the eusocial bee Lasioglossum laticeps. Their primary sequences were established as H‐Val‐Asn‐Trp‐Lys‐Lys‐Val‐Leu‐Gly‐Lys‐Ile‐Ile‐Lys‐Val‐Ala‐Lys‐NH2 (LL‐I), H‐Val‐Asn‐Trp‐Lys‐Lys‐Ile‐Leu‐Gly‐Lys‐Ile‐Ile‐Lys‐Val‐Ala‐Lys‐NH2 (LL‐II) and H‐Val‐Asn‐Trp‐Lys‐Lys‐Ile‐Leu‐Gly‐Lys‐Ile‐Ile‐Lys‐Val‐Val‐Lys‐NH2 (LL‐III). These lasioglossins exhibited potent antimicrobial activity against both Gram‐positive and Gram‐negative bacteria, low haemolytic and mast cell degranulation activity, and a potency to kill various cancer cells in vitro. The lasioglossin CD spectra were measured in the presence of trifluoroethanol and sodium dodecyl sulfate solution and indicated a high degree of α‐helical conformation. NMR spectroscopy, which was carried out in trifluoroethanol/water confirmed a curved α‐helical conformation with a concave hydrophobic and convex hydrophilic side. To understand the role of this bend on biological activity, we studied lasioglossin analogues in which the Gly in the centre of the molecule was replaced by other amino acid residues (Ala, Lys, Pro). The importance of the N‐terminal part of the molecule to the antimicrobial activity was revealed through truncation of five residues from both the N and C termini of the LL‐III peptide. C‐terminal deamidation of LL‐III resulted in a drop in antimicrobial activity, but esterification of the C terminus had no effect. Molecular modelling of LL‐III and the observed NOE contacts indicated the possible formation of a bifurcated H‐bond between hydrogen from the Lys15 CONH peptide bond and one H of the C‐terminal CONH2 to the Ile11 oxygen atom. Such interactions cannot form with C‐terminal esterification. 相似文献
93.
P3HT–PEO blend nanofibers were produced by electrospinning from chloroform solutions. A morphological study was carried out as a function of the processing parameters as well as the ratio between the two polymers. The fibers containing at least 60 wt.% of P3HT presented striated surfaces that could be explained by the alignment of the polymer domains along the fiber axis. The structural arrangement of the polymers was found to vary according to the polymers relative contents. The maximum electrical conductivity found for unaligned mats was 0.16 S/cm and increased to 0.3 S/cm when the nanofibers were aligned along a preferential direction. 相似文献
94.
Integrating waveform lidar with hyperspectral imagery for inventory of a northern temperate forest 总被引:2,自引:0,他引:2
Jeanne E. Anderson Lucie C. Plourde Bobby H. Braswell Ralph O. Dubayah J. Bryan Blair 《Remote sensing of environment》2008,112(4):1856-1870
It has been suggested that attempts to use remote sensing to map the spatial and structural patterns of individual tree species abundances in heterogeneous forests, such as those found in northeastern North America, may benefit from the integration of hyperspectral or multi-spectral information with other active sensor data such as lidar. Towards this end, we describe the integrated and individual capabilities of waveform lidar and hyperspectral data to estimate three common forest measurements - basal area (BA), above-ground biomass (AGBM) and quadratic mean stem diameter (QMSD) - in a northern temperate mixed conifer and deciduous forest. The use of this data to discriminate distribution and abundance patterns of five common and often, dominant tree species was also explored. Waveform lidar imagery was acquired in July 2003 over the 1000 ha. Bartlett Experimental Forest (BEF) in central New Hampshire (USA) using NASA's airborne Laser Vegetation Imaging Sensor (LVIS). High spectral resolution imagery was likewise acquired in August 2003 using NASA's Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). Field data (2001-2003) from over 400 US Forest Service Northern Research Station (USFS NRS) plots were used to determine actual site conditions.Results suggest that the integrated data sets of hyperspectral and waveform lidar provide improved outcomes over use of either data set alone in evaluating common forest metrics. Across all forest conditions, 8-9% more of the variation in AGBM, BA, and QMSD was explained by use of the integrated sensor data in comparison to either AVIRIS or LVIS metrics applied singly, with estimated error 5-8% lower for these variables. Notably, in an analysis using integrated data limited to unmanaged forest tracts, AGBM coefficients of determination improved by 25% or more, while corresponding error levels decreased by over 25%. When data were restricted based on the presence of individual tree species within plots, AVIRIS data alone best predicted species-specific patterns of abundance as determined by species fraction of biomass. Nonetheless, use of LVIS and AVIRIS data - in tandem - produced complementary maps of estimated abundance and structure for individual tree species, providing a promising adjunct to traditional forest inventory and conservation biology planning efforts. 相似文献
95.
Tareq Hussein Lenka Kubincová Lucie Džumbová Aleš Hruška Pavla Dohányosová Jiří Hemerka Jiří Smolík 《Building and Environment》2009
We investigated the deposition rate of aerosol particles (diameter between 0.03 and 5 μm) on rough surfaces of wallpapers, wall-plasters, and two types of carpets inside a test chamber. Compared to a smooth aluminum surface, the deposition rate of aerosol particles on the tested surfaces was up to 20 times depending on the surface roughness, mixing intensity, and particle size. A rough surface with a dimensionless surface roughness height k+ < 0.06 can be treated as a hydraulically smooth. The estimated deposition rates in this study and those predicted by a deposition model, which incorporates surface roughness, were in good agreement for coarse mode particles (diameter > 1 μm) when k+ < 1.04 and for ultrafine particles (diameter < 0.1 μm) when k+ < 0.48. The agreement between the model prediction and our estimation was better for coarse mode particles than for ultrafine particles. Deposition of aerosol particles, especially fine particles, needs more empirical investigations aiming at improving the existing models. 相似文献
96.
Monica Anese Barbara Quarta Lucie Peloux Sonia Calligaris 《Food research international (Ottawa, Ont.)》2011,44(9):2837-2842
The influence of the matrix composition and structure on the capacity of asparaginase to reduce acrylamide formation in biscuits was studied. In particular, formulations differing for water (10 to 20% on total weight) and fat (0 to 15% on total weight) content, fat type (margarine, palm oil) and lipid phase distribution were considered. In the latter case, palm oil was substituted with a monoglyceride–palm oil–water gel (hydrogel). The results showed that high water contents, by favoring precursor mobility, promoted acrylamide formation as well as the enzyme capability of reducing the toxic molecule levels in the final product. On the contrary, the presence of fat significantly reduced acrylamide development and enzyme activity as compared with the fat free formulation. It can be hypothesized that the presence of fat would hamper the interaction between the precursors in the aqueous phase, leading to lower amounts of acrylamide. By substituting fat with hydrogel, the biscuit behaved as a fat free system, where acrylamide formation as well as its reduction by means of asparaginase activity was higher than in the fat-containing biscuits. It is likely that the inclusion of palm oil in the dough through the hydrogel modified the system morphology, thus not hampering the encounter among reactants and consequently favoring acrylamide formation. 相似文献
97.
Lucie Chapelle Allan Lyckegaard Yukihiro Kusano Carsten Gundlach Mathilde Rosendahl Foldschack Dorthe Lybye Povl Brøndsted 《Journal of Materials Science》2018,53(9):6390-6402
A method to determine the orientation and diameter distributions of mineral wool fibre networks using X-ray tomography and image analysis is presented. The method is applied to two different types of mineral wool: glass wool and stone wool. The orientation information is obtained from the computation of the structure tensor, and the diameter is estimated by applying a greyscale granulometry. The results of the image analysis indicate the two types of fibres are distributed in a 2D planar arrangement with the glass wool fibres showing a higher degree of planarity than the stone wool fibres. The orientation information is included in an analytical model based on a Euler–Bernoulli beam approximation. The model enables prediction of the transverse stiffness. It is indicated that the glass wool transverse stiffness is lower than the stone wool transverse stiffness. Comparison with experimental results confirms the assumption that the underlying deformation mechanism of mineral wool is the bending of fibre segments between bonds. 相似文献
98.
Mycotoxin patulin represents potential health hazard especially in apple based baby food. There are already a lot of data to predict the fate of the toxin during the processing of fruits, but not enough for the apple puree and the existing data for apple puree are not usually consistent. The objective of the study was to evaluate the course of patulin degradation during the processing of apple puree under the conditions close to the real production process. The apple samples were spiked with patulin at four levels of concentration (539 μg/kg, 140 μg/kg, 23 μg/kg and <2 μg/kg). The patulin content changes during the processing were followed. The samples were taken after the homogenization, pulping, pasteurization and aseptic packaging. All operations of apple puree production contributed to patulin reduction. The principle operation was pulping, where the patulin levels were reduced from 29% to 80% of original content. 相似文献
99.
Jana Dvořáková Petr Šálek Lucie Korecká Ewa Pavlova Peter Černoch Olga Janoušková Barbora Koutníková Vladimír Proks 《应用聚合物科学杂志》2020,137(21):48725
The current work presents a pivotal study of the nanogelation of the linear poly(N5-2-hydroxypropyl-L-glutamine) polymer precursor containing tyramine (TYR) units in an inverse miniemulsion by horseradish peroxidase/H2O2-mediated crosslinking. The effects of various nH2O2/nTYR ratios on the kinetics of nanogelation in the inverse miniemulsion and on the reaction time are investigated by linear sweep voltammetry, while the formation of dityramine crosslinking is explored by fluorescence spectroscopy. The study is completed using dynamic light scattering measurements, nanoparticle tracking analysis, and cryogenic transmission electron microscopy to acquire comprehensive information about the formed nanoparticulate systems. With the optimal ratio nH2O2/nTYR = 2, the strategy yields in the high-quality ~ 130 nm poly(amino acid)-based nanogel, which is prepared in 2 h. The nanogel is colloidally stable under different temperature and pH conditions for over 168 h. Moreover, the demonstrated nanogel is noncytotoxic for HeLa cells and human primary fibroblasts and is quickly enzymatically hydrolyzed into small fragments during a biodegradation study in human blood plasma. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48725. 相似文献