Nanotechnology has brought significant advancements to agriculture through the development of engineered nanomaterials (ENPs). Silver nanoparticles (AgNPs) capped with polysaccharides have been ...applied in agricultural diagnostics, crop pest management, and seed priming. Hyaluronic acid (HA), a natural polysaccharide with bactericidal properties, has been considered a growth regulator for plant tissues and an inducer of systemic resistance against plant diseases. Additionally, HA has been employed as a stabilizing agent for AgNPs. This study investigated the synthesis and effects of hyaluronic acid-stabilized silver nanoparticles (HA-AgNPs) as a seed priming agent on lettuce (Lactuca sativa L.) seed germination. HA-AgNPs were characterized using several techniques, exhibiting spherical morphology and good colloidal stability. Germination assays conducted with 0.1, 0.04, and 0.02 g/L of HA-AgNPs showed a concentration-dependent reduction in seed germination. Conversely, lower concentrations of HA-AgNPs significantly increased germination rates, survival, tolerance indices, and seed water absorption compared to silver ions (Ag+). SEM/EDS indicated more significant potential for HA-AgNPs internalization compared to Ag+. Therefore, these findings are innovative and open new avenues for understanding the impact of Ag+ and HA-AgNPs on seed germination.
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•AgNPs stabilized with hyaluronic acid showed good colloidal stability.•HA-AgNPs influence water dynamics in Lettuce Seeds.•HA-AgNPs induced different biochemical alterations in seed tissues.•A dose-dependent accumulation of silver was observed in the lettuce seeds.•HA-AgNPs demonstrated superior silver internalization in lettuce seeds.
The effects of multiwall carbon nanotubes (MWCNTs) on the electrical, dielectric, and piezoelectric properties of the ferroelectric ceramic/castor‐oil polyurethane (PUR) composite films were ...evaluated. The three‐phase piezoelectric composites were produced by keeping PUR concentration constant while varying lead zirconate titanate (PZT) volume fractions between 10 and 50 vol.%, at two MWCNT concentrations: above and below percolation threshold. The dc electrical conductivity analysis revealed that small amounts of MWCNTs dispersed within PUR/PZT composite films can significantly improve electrical and piezoelectric properties due to their ability to act as conductive bridges between PZT particles in the samples. Using Jonscher's power law, it was possible to determine that the electrical conduction in ac regime occurs through spatial charge hopping between states located within the piezoelectric composite. Analyzing the piezoelectric properties through the d33 coefficient, it was found that PUR‐MWCNT/PZT piezoelectric composite displayed higher d33 values (20 pC/N) in comparison to the PUR/PZT two‐phase composite (9.5 pC/N) for all PZT loadings. According to these results, the dispersion of MWCNT nanoparticles influences the poling effectiveness of the PZT particles and increases the d33 coefficient of three‐phase piezoelectric composites.
Flexible piezoelectric nanocomposites have been the subject of a lot of recent research due to the development and use of wearable electronic devices and the increasing need for new harvesting ...devices and sensors due to increasingly intelligent and interconnected cities. In this study, flexible piezoelectric nanocomposites using elastomeric polyurethane (PU) as matrix, and lead zirconate titanate (PZT) as active phase, were produced using cellulose nanocrystals (CNC) as the third phase. The study describes the effect of CNC insertion on the morphology, thermal, electrical, and piezoelectric properties of the nanocomposites. It points out that the CNCs not only act to cause greater dispersion of the ceramic grains in the matrix, but also to lead to greater polarization effectiveness of the ceramic grains, resulting in a longitudinal piezoelectric coefficient (d33) increase of more than 370%, as compared with biphasic composites dependent on the ceramic and nanocrystals content.
There is great interest in the development of flexible piezoelectric composites forwearable electronic devices, sensors and harvesting devices. In this study, flexible piezoelectric nanocomposites were prepared using polyurethane as matrix, PZT and cellulose nanocrystals asthe second and third phases, respectively. The cellulose nanocrystals have been shown to improve the dispersion of the ceramic in the matrix and constitute the percolative path to the water. Such factors promoted a significant increase in the piezoelectric coefficient of the nanocomposites.
The use of nano- and microparticles as a release system for agrochemicals has been increasing in agricultural sector. However, the production of eco-friendly and smart carriers that can be easily ...handled in the environment is still a challenge for this technology. In this context, we have developed a biodegradable release system for the herbicide atrazine with magnetic properties. Herein, we investigated the (a) physicochemical properties of the atrazine-loaded magnetic poly(ε-caprolactone) microparticles (MPs:ATZ), (b) in vitro release kinetic profile of the herbicide, and (c) phytotoxicity toward photosynthesis in the aquatic fern Azolla caroliniana. The encapsulation efficiency of the herbicide in the MPs:ATZ was ca. 69%, yielding spherical microparticles with a diameter of ca. 100 μm, a sustained-release profile, and easily manipulated with an external magnetic field. Also, phytotoxicity issues showed that the MPs:ATZ maintained their herbicidal activity via inhibition of PSII, showing lower toxicity compared with the nonencapsulated ATZ at 0.01 and 0.02 μmol·L–1. Therefore, this technology may conveniently promote a novel magnetic controlled release of the herbicide ATZ (with the potential to be collected from a watercourse) and act as a nutrient boost to the nontarget plant, with good herbicidal activity and reduced risk to the environment.
Polymeric nanofibers have been intensively investigated in a wide range of areas, due to its unique characteristics, such as high surface area, attributed to the nanometric structures, high porosity, ...related to the elevated interconnectivity of the formed network, besides the excellent mechanical properties, what depends on the polymer used. Currently, an instrument that has been revolutionizing research in the synthesis of nanofibers, in the production of new materials or the incorporation of particles, is the airbrush. The most common method for producing nanofibers after eletrospinning is based on the solution blow spinning concept, using solution polymers or fused polymers, which requires two parallel concentric fluid streams: a polymer dissolved in a volatile solvent and a pressurized gas flowing around the polymer solution, creating fibers that are deposited in the direction of gas flow. In this work, a rapid and easy methodology was developed for the production of polyvinylidene fluoride (PVDF) micro and nanofibers using a commercially available airbrush and air compressor. Micrographs of scanning electron microscopy showed there is an optimal conditions for the formation of perfect fibers. Furthermore, the FTIR spectrum and the X-ray diffractogram displayed the existence of two distinct phases of the polymer, the predominant is the β-PVDF and the minority is the α-PVDF phase, which is related to the elongation suffered by the nanofiber during the spinning process, even addressed by her by the SBS technique.
In the present work, the electrical properties of a natural rubber‐based nanocomposite (NR) filled with cellulose nanowhiskers (CNW) coated with polyaniline (PANI) were studied. We developed a ...statistic model that simulates nanocomposite microstructure and conductivity, calculated using the transfer matrix technique. A two‐dimensional network of resistors representing a microstructure of both the insulating region (NR) and conductive fillers (cellulose nanowhiskers coated with polyaniline ‐ CNWP) was developed. The conductance of bond between two neighboring sites in the CNWP filler and two neighboring sites of the NR matrix was estimated using Drude's equation and Dyre's formula, respectively. Results of the simulations show that the conduction process between two sites of NR follows the modified Dyre model (RFEB), while between two CNWP sites follows the modified Drude model. The theoretical‐experimental adjustment shows that the electrical conduction process occurs via hopping and tunneling between states located inside the CNWP phase, randomly distributed in the rubber matrix.
This work aimed to compare the characteristics of micro and nanofibers of the poly (vinylidene fluoride) - PVDF polymer obtained by the Solution Blow Spinning (SBS) method, and films with those ...produced by other techniques, such as: casting and hot pressing. Thermogravimetric analysis (TGA) revealed that the films are thermally stable up to a temperature of 420 ° C. X-ray diffractometry (XRD) indicated the presence of the crystalline phases α and β, the β phase being more evident for nanofibers and PVDF casting. The film obtained by SBS showed a greater contact angle, showing to be more hydrophobic. Strain tests showed that the nanofiber films showed a 72% rupture to rupture, about 1.7 and 3.1 times greater than those obtained by casting and hot pressing, respectively. There was also a decrease in the modulus of elasticity and the limit of tensile strength of nanofibers, compared to other films.
The original version of this article unfortunately contained a mistake. In Table 1 of the published online paper, there are four commas (,) that must be changed to periods (.).
Tectona grandis wood presents decent dimensional stability as well as highly suitable physical and mechanical properties. These characteristics have encouraged the intense usage of this species, ...which also includes the reuse of wood processing waste for panel production. Using teak wood waste, this study aims to manufacture and evaluate heat-pressed particleboards at 5 MPa and 100 °C, by being glued with castor oil-based polyurethane resin at proportions of 10% for the homogeneous boards and 12% for the heterogeneous solutions. Single-layer (homogeneous) boards were compared with three-layer particleboard specimens (heterogeneous) having the finer particles in the outer layers. The basic density, moisture content, modulus of rupture and modulus of elasticity in the static bending and perpendicular tensile, water absorption, and thickness swelling after 24 h were evaluated to support this comparative study. All the manufactured particleboards met the standardized requirements of performance, thus being very feasible for usage as non-structural boards. When the two different compositions were analyzed, a considerably better performance of the three-layered particleboards was identified when compared to the homogeneous panels.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Schistosomiasis remains a serious health issue nowadays for an estimated one billion people in 79 countries around the world. Great efforts have been made to identify good vaccine candidates during ...the last decades, but only three molecules reached clinical trials so far. The reverse vaccinology approach has become an attractive option for vaccine design, especially regarding parasites like
spp. that present limitations for culture maintenance. This strategy also has prompted the construction of multi-epitope based vaccines, with great immunological foreseen properties as well as being less prone to contamination, autoimmunity, and allergenic responses. Therefore, in this study we applied a robust immunoinformatics approach, targeting
transmembrane proteins, in order to construct a chimeric antigen. Initially, the search for all hypothetical transmembrane proteins in GeneDB provided a total of 584 sequences. Using the PSORT II and CCTOP servers we reduced this to 37 plasma membrane proteins, from which extracellular domains were used for epitope prediction. Nineteen common MHC-I and MHC-II binding epitopes, from eight proteins, comprised the final multi-epitope construct, along with suitable adjuvants. The final chimeric multi-epitope vaccine was predicted as prone to induce B-cell and IFN-γ based immunity, as well as presented itself as stable and non-allergenic molecule. Finally, molecular docking and molecular dynamics foresee stable interactions between the putative antigen and the immune receptor TLR 4. Our results indicate that the multi-epitope vaccine might stimulate humoral and cellular immune responses and could be a potential vaccine candidate against schistosomiasis.
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