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result(s) for
"Peer, Petra"
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Characterization of Poly(Ethylene Oxide) Nanofibers—Mutual Relations between Mean Diameter of Electrospun Nanofibers and Solution Characteristics
2019
The quality of electrospun poly(ethylene oxide) (PEO) nanofibrous mats are subject to a variety of input parameters. In this study, three parameters were chosen: molecular weight of PEO (100, 300, 600, and 1000 kg/mol), PEO concentration (in distilled water), and shear viscosity of PEO solution. Two relations free of any adjustable parameters were derived. The first, describing the initial stage of an electrospinning process expressing shear viscosity using PEO molecular weight and concentration. The second, expressing mean nanofiber diameter using concentration and PEO molecular weight. Based on these simple mathematical relations, it is possible to control the mean nanofiber diameter during an electrospinning process.
Journal Article
Structural and Histomorphological Evaluation of the Stifle Joint Capsule in Canine Congenital Patellar Luxation and Cranial Cruciate Ligament Rupture
2025
Congenital patellar luxation (PL) and cranial cruciate ligament rupture (CCLR) are among the most prevalent hereditary musculoskeletal disorders in dogs. Despite their frequency, the microstructural alterations in the stifle joint capsule associated with these conditions remain poorly understood. This study aimed to characterize histomorphological changes in the joint capsule of dogs affected by PL and/or CCLR. Capsule samples were collected from dogs undergoing corrective surgery for PL or CCLR, while control tissue was obtained from dogs with unrelated orthopedic conditions. Histological evaluation assessed capsule thickness, the organization of its layers (stratum fibrosum, stratum subsynoviale, and stratum synoviale), synovial cell number, and villous or plicae formation. Associations with disease type, chronicity, sex, age, breed, and weight were analyzed. Dogs with PL and CCLR exhibited increased superficial synovial cell layers compared to controls, whereas chronic cases showed reduced villous formation (SEF = 2.46). Absence or marked reduction of the stratum subsynoviale correlated with PL and prolonged lameness. In PL cases, the stratum synoviale was frequently absent, whereas CCLR cases exhibited an increase in overall capsular thickness. These findings reveal distinct histomorphological remodeling in PL and CCLR, suggesting that chronic instability drives degenerative changes. Understanding these alterations may aid in early diagnosis, improve treatment strategies, and inform breeding programs targeting joint stability in predisposed breeds.
Journal Article
Reuse of Textile Waste to Production of the Fibrous Antibacterial Membrane with Filtration Potential
by
Frajová, Jaroslava
,
Hrůza, Jakub
,
Sedlaříková, Jana
in
Antibacterial agents
,
antibacterial membrane
,
Antifouling substances
2021
Wasted synthetic fabrics are a type of textile waste source; the reuse of them brings environmental protection and turns waste into a valuable material. In this work, the used nylon (polyamide) stockings were transmuted into a fine fibrous membrane via an electrospinning process. In addition, the safety antibacterial agent, monoacylglycerol (MAG), was incorporated into a recycled fibrous membrane. The results revealed that the neat, recycled polyamide (rPA) fibers with a hydrophobic surface could be converted into hydrophilic fibers by blending various amounts of MAG with rPA solution prior to electrospinning. The filtration efficiency and air/water vapor permeability of the two types of produced membranes, neat rPA, and rPA/MAG, were tested. Their filtration efficiency (E100) was more than 92% and 96%, respectively. The membranes were classified according to Standard EN1822, and therefore, the membranes rPA and rPA/MAG were assigned to the classes E10 and E11, respectively. The air permeability was not affected by the addition of MAG, and water vapor permeability was slightly enhanced. Based on the obtained data, prepared rPA/MAG fibrous membranes can be evaluated as antifouling against both tested bacterial strains and antimicrobial against S. aureus.
Journal Article
Effect of Oregano and Marjoram Essential Oils on the Physical and Antimicrobial Properties of Chitosan Based Systems
2017
The effect of two essential oils (EOs), from Origanum vulgare and Origanum majorana, their structural properties, and concentration on physical and antimicrobial characteristics of chitosan based solutions as well as films was investigated. Results showed that significantly different behaviour was induced by variation in the compositions of given essential oils. Film-forming solutions (FFS) containing oregano oil comprised considerably greater particles in comparison with the marjoram samples. Similarly, structural changes were confirmed by SEM analysis of chitosan films modified with the EOs; the smaller particles of the marjoram oil demonstrated better compatibility with chitosan matrix. However, chitosan films enriched with the oregano oil showed significantly superior antimicrobial activity compared to the marjoram. The dissimilar effects of the two EOs were also observed by water vapour pressure (WVP) measurement; increasing the amount of oregano oil triggered a drop in the WVP of the prepared films, whereas the marjoram oil had a negligible impact in this respect. These results suggest that the structural features of active substances in the EOs play a crucial role in determining the final properties of FFS and biofilm systems.
Journal Article
Electrospinning of a Copolymer PVDF-co-HFP Solved in DMF/Acetone: Explicit Relations among Viscosity, Polymer Concentration, DMF/Acetone Ratio and Mean Nanofiber Diameter
2021
The process of electrospinning polymer solutions depends on many entry parameters, with each having a significant impact on the overall process and where complexity prevents the expression of their interplay. However, under the assumption that most parameters are fixed, it is possible to evaluate the mutual relations between pairs or triples of the chosen parameters. In this case, the experiments were carried out with a copolymer poly(vinylidene-co-hexafluoropropylene) solved in mixed N,N’-dimethylformamide (DMF)/acetone solvent for eight polymer concentrations (8, 10, 12, 15, 18, 21, 24, and 27 wt.%) and five DMF/acetone ratios (1/0, 4/1, 2/1, 1/1, 1/2). Processing of the obtained data (viscosity, mean nanofiber diameter) aimed to determine algebraic expressions relating both to viscosity and a mean nanofiber diameter with polymer concentration, as well as DMF/acetone ratio. Moreover, a master curve relating these parameters with no fitting factors was proposed continuously covering a sufficiently broad range of concentration as well as DMF/acetone ratio. A comparison of algebraic evaluation with the experimental data seems to be very good (the mean deviation for viscosity was about 2%, while, for a mean nanofiber diameter was slightly less than 10%).
Journal Article
Zein-Based Films Containing Monolaurin/Eugenol or Essential Oils with Potential for Bioactive Packaging Application
by
Pavlatkova, Lucie
,
Janalikova, Magda
,
Peer, Petra
in
Anti-Bacterial Agents - pharmacology
,
Antifungal Agents - pharmacology
,
Antimicrobial agents
2021
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.
Journal Article
Electrospun Sound-Absorbing Nanofibrous Webs from Recycled Poly(vinyl butyral)
2022
The amount of poly(vinyl butyral) (PVB) foils added to car windscreens to suppress glass shattering represents a huge worldwide volume of the material, and once a vehicle is end-of-life it also becomes a significance contributor to landfill. The recycling of PVB materials from windscreens has been expensive and despite improvements in recycling technologies, the landfill burden still increases. However, an increase in oil prices can shift the economic balance and stimulates the possible applicability of recycled PVB. As PVB is a relatively easy electrospinnable material, it is shown that nanofibrous mats produced from recycled PVB blends in ethanol exhibit very good sound-absorbing properties. To achieve an optimal composition between virgin and recycled PVB blends, a series of their ratios was consecutively characterized using various techniques (rheometry, SEM, FTIR, DSC, TGA, DMA, an impedance tube for determining sound absorbance). The best result was obtained with two wt. portions of 8 wt.% solution of virgin PVB in ethanol and one wt. portion of 12 wt.% solution of recycled PVB in ethanol.
Journal Article
Effect of Thermal Treatment on Crystallinity of Poly(ethylene oxide) Electrospun Fibers
by
Peer, Petra
,
Polaskova, Martina
,
Cermak, Roman
in
Communication
,
Crystal structure
,
Crystallinity
2019
Post-process thermal treatment of electrospun fibers obtained from poly(ethylene oxide) (PEO) water and methanol solutions was examined. PEO fibers from methanol solution showed larger diameters as observed by scanning electron microscopy. Fibers both from water and methanol solutions exhibited a significant dimensional stability and surface cracking during the specific exposure time after thermal treatments at 40, 50, and 60 °C. Changes in crystallinity after the thermal treatment were studied by wide-angle X-ray diffraction. The kinetics of secondary crystallization were positively influenced by the as-processed level of the amorphous phase and temperature of thermal treatment. Samples treated at 60 °C were degraded by thermooxidation within the time.
Journal Article
Antibacterial and Antifouling Efficiency of Essential Oils-Loaded Electrospun Polyvinylidene Difluoride Membranes
by
Sedlaříková, Jana
,
Peer, Petra
,
Bartošová, Lucie
in
Anti-Bacterial Agents - chemistry
,
Anti-Bacterial Agents - pharmacology
,
Biofouling - prevention & control
2022
Nanofibers have become a promising material in many industries in recent years, mainly due to their various properties. The only disadvantage of nanofibers as a potential filtration membrane is their short life due to clogging by bacteria in water treatment. The enrichment of nanofibers with active molecules could prevent these negative effects, represented by essential oils components such as Thymol, Eugenol, Linalool, Cinnamaldehyde and Carvacrol. Our study deals with the preparation of electrospun polyvinylidene difluoride (PVDF)-based nanofibers with incorporated essential oils, their characterization, testing their antibacterial properties and the evaluation of biofilm formation on the membrane surface. The study of the nanofibers’ morphology points to the nanofibers’ diverse fiber diameters ranging from 570 to 900 nm. Besides that, the nanofibers were detected as hydrophobic material with wettability over 130°. The satisfactory results of PVDF membranes were observed in nanofibers enriched with Thymol and Eugenol that showed their antifouling activity against the tested bacteria Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. Therefore, these PVDF membranes could find potential applications as filtration membranes in healthcare or the environment.
Journal Article
Circulatory Management of Polymer Waste: Recycling into Fine Fibers and Their Applications
by
Peer, Petra
,
Andicsová, Anita Eckstein
,
Rychter, Piotr
in
Alternative technology
,
Biodegradable materials
,
Cellulose
2021
In modern society, it is impossible to imagine life without polymeric materials. However, managing the waste composed of these materials is one of the most significant environmental issues confronting us in the present day. Recycling polymeric waste is the most important action currently available to reduce environmental impacts worldwide and is one of the most dynamic areas in industry today. Utilizing this waste could not only benefit the environment but also promote sustainable development and circular economy management. In its program statement, the European Union has committed to support the use of sorted polymeric waste. This study reviews recent attempts to recycle this waste and convert it by alternative technologies into fine, nano-, and microscale fibers using electrospinning, blowing, melt, or centrifugal spinning. This review provides information regarding applying reprocessed fine fibers in various areas and a concrete approach to mitigate the threat of pollution caused by polymeric materials.
Journal Article