Previously, a new biodegradable poly(ester urethane urea) was synthesized based on polycaprolactone-diol and fish gelatin (PU-Gel). In this work, the potential of this new material for neural tissue engineering is evaluated. Membranes with randomly oriented fibers and with aligned fibers are produced using electrospinning and characterized regarding their mechanical behavior under both dry and wet conditions. Wet samples exhibit a lower Young's modulus than dry ones and aligned membranes are stiffer and more brittle than those randomly oriented. Cyclic tensile tests are conducted and high values for recovery ratio and resilience are obtained. Both membranes exhibited a hydrophobic surface, measured by the water contact angle (WCA). Human mesenchymal stem cells from umbilical cord tissue (UC-MSCs) and human neural stem cells (NSCs) are seeded on both types of membranes, which support their adhesion and proliferation. Cells stained for the cytoskeleton and nucleus in membranes with aligned fibers display an elongated morphology following the alignment direction. As the culture time increased, higher cell viability is obtained on randomfibers for UC-MSCs while no differences are observed for NSCs. The membranes support neuronal differentiation of NSCs, as evidenced by markers for a neuronal filament protein (NF70) and for a microtubule-associated protein (MAP2).
- MeSH
- biokompatibilní materiály chemie farmakologie MeSH
- buněčná adheze účinky léků MeSH
- buněčná diferenciace účinky léků MeSH
- kultivované buňky MeSH
- lidé MeSH
- mezenchymální kmenové buňky * cytologie účinky léků metabolismus MeSH
- nervové kmenové buňky * cytologie účinky léků metabolismus MeSH
- pevnost v tahu MeSH
- polyestery * chemie farmakologie MeSH
- polyurethany * chemie farmakologie MeSH
- proliferace buněk účinky léků MeSH
- testování materiálů MeSH
- tkáňové inženýrství * metody MeSH
- tkáňové podpůrné struktury chemie MeSH
- viabilita buněk účinky léků MeSH
- želatina * chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Despite the obvious benefits of using ureteral stents to drain the ureters, there is also a risk of complications from 80-90%. The presence of a foreign body in the human body causes disturbances in its proper functioning. It can lead to biofilm formation on the stent surface, which may favor the development of urinary tract infections or the formation of encrustation, as well as stent fragmentation, complicating its subsequent removal. In this work, the effect of the polymeric coating containing the active substance-papaverine hydrochloride on the functional properties of ureteral stents significant for clinical practice were assessed. Methods: The most commonly clinically used polyurethane ureteral Double-J stent was selected for the study. Using the dip-coating method, the surface of the stent was coated with a poly(D,L-lactide-glycolide) (PLGA) coating containing the papaverine hydrochloride (PAP). In particular, strength properties, retention strength of the stent ends, dynamic frictional force, and the fluoroscopic visibility of the stent during X-ray imaging were determined. Results: The analysis of the test results indicates the usefulness of a biodegradable polymer coating containing the active substance for the modification of the surface of polyurethane ureteral stents. The stents coated with PLGA+PAP coating compared to polyurethane stents are characterized by more favorable strength properties, the smaller value of the dynamic frictional force, without reducing the fluoroscopic visibility.
- MeSH
- biokompatibilní materiály farmakologie MeSH
- kopolymer kyseliny glykolové a mléčné farmakologie MeSH
- lidé MeSH
- obstrukce močovodu metabolismus chirurgie terapie MeSH
- papaverin metabolismus farmakologie MeSH
- polyurethany chemie MeSH
- stenty uvolňující léky * MeSH
- vstřebatelné implantáty MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The main aims of the research were to produce efficient nanofibrous filters with long-term antibacterial properties and to confirm the functionality of samples under real filtration conditions. A polyurethane solution was modified by micro- or nanoparticles of copper oxide in order to juxtapose the aggregation tendency of particles depending on their size. Modified solutions were electrospun by the Nanospider technique. The roller spinning electrode with a needle surface and static wire electrode were used for the production of functionalized nanofibers. The antibacterial properties of the modified nanofibrous layers were studied under simulated conditions of water and air filtration. Particular attention was paid to the fixation mechanism of modifiers in the structure of filters. It was determined that the rotating electrode with the needle surface is more efficient for the spinning of composite solutions due to the continuous mixing and the avoidance of particle precipitation at the bottom of the bath with modified polyurethane. Moreover, it was possible to state that microparticles of copper oxide are more appropriate antimicrobial additives due to their weaker aggregation tendency but stronger fixation in the fibrous structure than nanoparticles. From the results, it is possible to conclude that nanofibers with well-studied durable antibacterial properties may be recommended as excellent materials for water and air filtration applications.
Increasing use of current-use pesticides (CUPs) in Africa raises environmental and public health concerns. But there is a large uncertainty about their occurrence and the composition of pesticide mixtures on this continent. This paper investigates the presence of 27 CUPs in air across 20 sampling sites in Africa. 166 passive air samples, consisting of polyurethane foam (PUF), were collected in 12 African countries between 2010 and 2018. Samples were extracted with methanol and analyzed via high-performance liquid chromatography coupled with tandem mass spectrometry. The detection frequencies of CUPs per site were compared to land use patterns and sampling years, while their similarities were assessed using hierarchical cluster analysis. Overall, 24 CUPs were detected at least once. In 93% of all samples, at least one CUP was detected, while 78% of the samples had mixtures of two or more CUPs (median 3, interquartile range 5). Atrazine and chlorpyrifos were detected in 19 out of 20 sampling sites. Carbaryl, metazachlor, simazine, tebuconazole and terbuthylazine had the highest detection frequencies at sampling sites dominated by croplands. Across all the sampling years, 16 CUPs were present. Seven CUPs were newly detected from 2016 onwards (azinfos-methyl, dimetachlor, chlorsulfuron, chlortoluron, isoproturon, prochloraz and pyrazon), while metamitron was only present before 2012. Sites within a radius of about 200 km showed similarities in detected CUP mixtures across all samples. Our results show the presence of CUP mixtures across multiple agricultural and urban locations in Africa which requires further investigation of related environmental and human health risks.
Nanofiber scaffolds provide numerous advantages over common carriers engineered for microorganisms. The most important advantage is an increased speed of primary surface colonization (up to four times faster), which shortens the time required for the areal biofilm formation and optimum performance of attached microorganisms (higher efficiency of biological activity of up to twice as fast). Image analysis predicts early formation of biofilm even in beginning stages; analysis of biofilm reveals the different structures of bacterial colonies on both scaffolds (higher porosity, size, and number of bacterial colonies on nanofiber's surface). The image analysis correlates well with determinations of dry matter (linear correlation of 0.96) and proteins (linear correlation of 0.89).
- MeSH
- biofilmy * MeSH
- kultivační média * MeSH
- nanovlákna * MeSH
- polyurethany MeSH
- poréznost MeSH
- Rhodococcus MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
This paper deals with the development and characteristics of the properties of a permeable water-resistant heat insulation panel based on recycled materials. The insulation panel consists of a thermal insulation core of recycled soft polyurethane foam and winter wheat husk, a layer of geopolymer that gives the entire sandwich composite strength and fire resistance, and a nanofibrous membrane that permits water vapor permeability, but not water in liquid form. The observed properties are the thermal conductivity coefficient, volumetric heat capacity, fire resistance, resistance to long-term exposure of a water column, and the tensile strength perpendicular to the plane of the board. The results showed that while the addition of husk to the thermal insulation core does not significantly impair its thermal insulation properties, the tensile strength perpendicular to the plane of these boards was impaired by the addition of husk. The geopolymer layer increased the fire resistance of the panel for up to 13 min, and the implementation of the nanofibrous membrane resulted in a water flow of 154 cm2 in the amount of 486 g of water per 24 h at a water column height of 0.8 m.
Polyurethane has a good insulation characteristic, and it is widely used as an insulation and lining material for refrigerators. Nevertheless, at the end of a product's lifetime, serious problems arise related to waste management. Recently, energy recovery has been marked as a promising solution, especially, waste-to-energy applications. To find an appropriate application for such waste, a thermal analysis was performed. An experimental analysis of polyurethane (PU) waste material was performed by the method of pyrolysis gas chromatography with mass spectrometric detection (Py-GC/MS) at various pyrolytic temperatures, namely, at 500, 600 and 700 °C. Waste polyurethane foam was conducted to investigations in the form of a bulk sample and sorted grain-size samples with a goal to detect the chemical composition of the pyrolysate. The investigation revealed various groups of organic compounds such as heterocyclic compounds of nitrogen and simple and polycyclic aromatic hydrocarbons, while notable concentrations of compounds containing chlorine were detected as well. The experimental analysis found differences in the composition of amines and other compounds and in the dependence on grain size composition. Bulk samples produced the highest concentration of amines (˃ 40%) at a temperature of 500 °C. The sample homogenization led to a significant increase in amines production. Polyurethane waste of grain size from 0.125 to 0.25 mm contained approximately 80% amines. The pyrolysis of the bulk sample at 600 °C yielded only 24% nitrogen heterocyclic compounds, while from the sorted grain-size <0.045 mm and 0.045-0.063 mm, yields were increased to 47.4 and 45.7%, respectively.
The valorization of lignins as renewable aromatic feedstock is of utmost importance in terms of the use of sustainable resources. This study provides a deductive approach towards market-oriented lignin-derived antioxidants by ascertaining the direct effect of different structural features of lignin on the reactivity of its phenolic OH groups in the radical scavenging reactions. The antioxidant activity of a series of compounds, modeling lignin structural units, was experimentally characterized and rationalized, using thermodynamic descriptors. The calculated O-H bond dissociation enthalpies (BDE) of characteristic lignin subunits were used to predict the modification pathways of technical lignins. The last ones were isolated by soda delignification from different biomass sources and their oligomeric fractions were studied as a raw material for modification and production of optimized antioxidants. These were characterized in terms of chemical structure, molecular weight distribution, content of the functional groups, and the antioxidant activity. The developed approach for the targeted modification of lignins allowed the products competitive with two commercial synthetic phenolic antioxidants in both free radical scavenging and stabilization of thermooxidative destruction of polyurethane films.
- MeSH
- antioxidancia chemická syntéza MeSH
- dimerizace MeSH
- elektrony MeSH
- kinetika MeSH
- lignin chemie MeSH
- polyfenoly chemie MeSH
- polyurethany chemie MeSH
- protonová magnetická rezonanční spektroskopie MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- teoretické modely * MeSH
- teorie funkcionálu hustoty * MeSH
- teplota MeSH
- vodík chemie MeSH
- Publikační typ
- časopisecké články MeSH
Poly(lactic acid)-block-poly(oxirane)s (PLA-b-POE) of various compositions were prepared using a one-pot approach and then extended in a reaction with l-lysine diethyl ester diisocyanate, thereby forming polyester-ether-urethanes (PEU) with prolonged chains and units with increased degradability. The PEUs are processed by electrospinning to prepare degradable nanofibrous sheet materials with and without encapsulating the antibiotic Vancomycin (VAC). PLA block isomerism and POE blocks oligomeric content (1000 g/mol) affect the thermal properties, processability, nanofibrous sheet morphology, abiotic degradation, cytocompatibility, and encapsulated antibiotic release rate of prepared PEUs. Therefore, our findings provide an effective approach to tuning the functional properties of these advanced biocompatible materials. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2378-2387, 2019.
- MeSH
- antibakteriální látky * chemie farmakologie MeSH
- buňky NIH 3T3 MeSH
- lékové transportní systémy * MeSH
- myši MeSH
- nanovlákna chemie MeSH
- polyestery chemie farmakologie MeSH
- polyethylenglykoly chemie farmakologie MeSH
- polyurethany chemie farmakologie MeSH
- testování materiálů * MeSH
- vankomycin * chemie farmakologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
PBDEs were measured in air and soil across Azerbaijan to establish contemporary concentrations at 13 urban and rural sites. Polyurethane foam passive air samplers (PUF-PAS) were deployed for a period of a month with surface soil samples collected at the same sites. Unlike organochlorine pesticides previously surveyed by our group, PBDE concentrations in both contemporary air and soil were low in comparison to recent European and Asian studies. For example, mean ∑9PBDE concentrations in air and soil were 7.13 ± 1.66 pg m-3 and 168 ± 57 pg g-1, respectively. The fully brominated BDE-209 was the most abundant congener observed in soil (174.8 ± 58.5 pg g-1), comprising ~ 96% of ∑10PBDE. However, the PAS-derived air concentrations for highly brominated congeners must be viewed with caution as there is uncertainty over the uptake rates of particle-bound chemicals using these devices. Some of the highest concentrations in air were observed at sites with the highest wind speeds and at several remote locations in the north of the country and this requires further research. Levels of BDE-47 and 99 (the two most abundant congeners in the widely used penta-formulation) were lower than levels reported elsewhere suggesting limited use/import of the penta-BDE formulation in Azerbaijan.
- MeSH
- halogenované difenylethery analýza MeSH
- látky znečišťující půdu analýza MeSH
- látky znečišťující vzduch analýza MeSH
- monitorování životního prostředí MeSH
- pesticidy analýza MeSH
- polyurethany analýza MeSH
- půda chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Ázerbájdžán MeSH
