Addition Of ZnO Nanoparticles Research Articles

Cryoprotective Effect of Zinc and Gold Nanoparticles During Cooling and Freeze-thawing on Marwari Stallion Sperm Parameters and Reactive Oxygen Species Production

BACKGROUND: Sperm cryopreservation is one of the most important procedures in the development of biotechnologies for assisted reproduction. Cryopreservation of stallion spermatozoa tends to cause plasma membrane damage due to the low ratio of cholesterol to phospholipids. Different substances and compounds can be added to semen extenders to improve sperm quality. OBJECTIVE: To investigate the effect of supplementing semen extender with zinc nanoparticles (ZnONPs) and gold nanoparticles (AuNPs) on cooled and frozen-thawed spermatozoa of Marwari stallion. MATERIALS AND METHODS: A total of 20 ejaculates from four Marwari stallions (five ejaculates from each) were collected. The gel free semen was extended with primary extender in equal volume and then divided in three equal groups, namely control (C), zinc (ZnO) and gold (Au), and centrifuged to obtain a final concentration of 100-150 x10 6 mL -1 and then cryopreserved. Cooled and post-thaw semen evaluations were conducted for various seminal characteristics, viz. progressive sperm motility, sperm plasma membrane integrity, sperm viability, acrosome integrity and mitochondrial membrane potential. RESULTS: Cooled semen (4ºC for 2 h) evaluation revealed nonsignificant differences among the groups (C, ZnO and Au) for all the semen quality parameters. However, at the post-thaw stage, progressive sperm motility, sperm plasma membrane integrity, acrosome integrity and oxidative parameters were significantly (P≤ 0.01) higher in the ZnO group than Au and C. CONCLUSION: The addition of ZnO nanoparticles improves the post thaw quality of stallion spermatozoa by reducing the oxidative stress, but Au nanoparticles had no effect on cooled as well as post-thaw semen quality.

ZnO-NaNO3 nanocomposites for solar thermal energy storage systems

High-temperature phase change materials (PCMs) with good energy storage density and thermal conductivity are needed to utilize solar thermal energy effectively to meet industrial thermal energy demands. Composite PCMs containing a material of higher thermal conductivity and an inorganic high-temperature PCM can be explored to meet these requirements. Accordingly, a high-temperature, composite inorganic PCM (ZnO-NaNO3) with enhanced thermophysical properties was prepared, and its energy storage potential was investigated experimentally. A maximum thermal conductivity enhancement of 22.7% was achieved at 200 °C for 2 wt% ZnO-NaNO3 nanocomposite. The increase in thermal conductivity at higher temperatures may be attributed to the formation of ordered sodium nitrate layers on the nanoparticle surfaces. The increase in surface area and surface energy due to the addition of ZnO nanoparticles increased the specific heat of the nanocomposite in both the solid and liquid phases (43.5% in the liquid phase for 2 wt% ZnO-NaNO3). Thus, the addition of ZnO nanoparticles to NaNO3 increased its energy storage capacity. The addition of ZnO nanoparticles to NaNO3 did not affect the onset, peak or endset temperature during melting and freezing. Moreover, 2 wt% ZnO-NaNO3 exhibited cyclic stability even after 500 cycles and thus has potential as an energy storage medium.

Increasing efficiency in perovskite solar cells through energy downconversion using nanoparticles

The generation of electricity through solar energy stands out as one of the fastest-growing renewable energy sources worldwide. The global demand for energy, coupled with the rising levels of CO2 in the atmosphere, highlights the need to develop renewable sources of energy. The current challenge of utilizing photovoltaic cells for electricity production lies in the efficiency of the photovoltaic conversion process occurring within the device. To enhance the efficiency of photovoltaic devices, scientists have been investigating light conversion processes to improve radiation absorption and conversion. The study and application of the downconversion process with luminescent materials have been explored to prevent energy loss in solar devices. Zinc Oxide nanoparticles (ZnO NPs) have been employed for this purpose due to their favorable optical properties for downconversion applications. Organic–inorganic perovskites, such as methylammonium lead iodide perovskite (CH3NH3PbI3), have shown promising results for power conversion efficiency, and the present study aimed to assess the increased efficiency of perovskite devices with the addition of ZnO nanoparticles on top of the device. Such optical improvement in the device can occur because high-energy photons, which would be absorbed by layers such as glass and ITO, which are not semiconductors and do not generate charge carriers, will now be absorbed by the ZnO NPs and emitted at longer wavelengths. These longer wavelengths will be absorbed in the active layer of the device, thus generating charge carriers. The obtained results demonstrated that ZnO nanoparticles with approximately 45 nm diameter can successfully produce a downconversion process, leading to improved light absorption by the active layer of the cell and consequently improving photovoltaic efficiency of a perovskite device by 5.5 %.

Tuning optical, magnetic, and electrical parameters of CuFe2O4 nanoparticles incorporated with GO and ZnO using a facile synthesis

Nano-ferrites, metal oxides, and carbon-based nanomaterials have been used frequently to enhance optical and magnetic prospects for latent applications. Copper ferrite/Graphene Oxide and Zinc Oxide (CuFe2O4/GO/ZnO) ternary nanocomposite synthesized by hydrothermal route showed dramatically good outcomes as the band gap energy value of synthesized nanocomposite approaches to 2.4 eV. Furthermore, the light absorbance of CuFe2O4 increases by adding ZnO and GO. The experimental data revealed the face-centered cubic structure (FCC) of pure spinal ferrite (CuFe2O4) nanoparticles even after adding ZnO and GO. The 2θ peak observed at 31.70° with (220) hkl planes indicates the successful addition of ZnO nanoparticles in CuFe2O4/GO nanocomposite. XRD graph, the absence of characteristic peaks of GO revealed the intercalation of CuFe2O4 nanoparticles with GO layers. In SEM images, agglomeration among CuFe2O4 nanoparticles is observed due to the magnetic interaction of nano-crystallite with a high surface-to-volume (S/V) ratio. VSM can be used to determine the magnetic properties of as-synthesized samples at moderate temperatures under 0–0.5 and ± 5 tesla. In CuFe2O4/GO/ZnO ternary nanocomposite, the saturation magnetization value reduces from 2.071 to 1.365 emu/g due to the addition of ZnO nanoparticles. The loops were narrowed showing a decrease in the coercive field with the addition of ZnO nanoparticles in CuFe2O4/GO ternary nanocomposite material. Moreover, the study of electrical properties of pure CuFe2O4 and CuFe2O4/GO/ZnO ternary nanocomposite revealed that the values of dielectric constant and tangent loss decrease at high frequencies owing to surface charge polarization and intrinsic dipole interactions. The study of the electrical properties of both pure CuFe2O4 and the CuFe2O4/GO/ZnO ternary nanocomposite reveals that the dielectric constant (ε’) and tangent loss (tanδ) exhibit a decreasing trend as the frequency increases. This behavior is attributed to surface charge polarization and intrinsic dipole interactions. At lower frequencies, both samples display elevated values for these properties, which stabilize as the frequency increases beyond 2 MHz. Notably, high AC conductivity is observed in both samples, attributed to increased capacitance and resistance.

Antimicrobial Packaging for Plum Tomatoes Based on ZnO Modified Low-Density Polyethylene.

Food safety and quality are major concerns in the food industry. Despite numerous studies, polyethylene remains one of the most used materials for packaging due to industry reluctance to invest in new technologies and equipment. Therefore, modifications to the current materials are easier to implement than adopting whole new solutions. Antibacterial activity can be induced in low-density polyethylene films only by adding antimicrobial agents. ZnO nanoparticles are well known for their strong antimicrobial activity, coupled with low toxicity and UV shielding capability. These characteristics recommend ZnO for the food industry. By incorporating such safe and dependable antimicrobial agents in the polyethylene matrix, we have obtained composite films able to inhibit microorganisms' growth that can be used as packaging materials. Here we report the obtaining of highly homogenous composite films with up to 5% ZnO by a melt mixing process at 150 °C for 10 min. The composite films present good transparency in the visible domain, permitting consumers to visualize the food, but have good UV barrier properties. The composite films exhibit good antimicrobial and antibiofilm activity from the lowest ZnO composition (1%), against both Gram-positive and Gram-negative bacterial strains. The homogenous dispersion of ZnO nanoparticles into the polyethylene matrix was assessed by Fourier transform infrared microscopy and scanning electron microscopy. The optimal mechanical barrier properties were obtained for composition with 3% ZnO. The thermal analysis indicates that the addition of ZnO nanoparticles has increased thermal stability by more than 100 °C. The UV-Vis spectra indicate a low transmittance in the UV domain, lower than 5%, making the films suitable for blocking photo-oxidation processes. The obtained films proved to be efficient packaging films, successfully preserving plum (Rome) tomatoes for up to 14 days.

Immobilization of Cu2+ enhances the anti-mould properties of bamboo by addition of ZnO nanoparticles

Alkaline Copper Quaternary (ACQ) is widely used to improve the anti-mould properties of bamboo in industry. In this paper, ZnO nanoparticles are employed to enhance the immobilization of Cu2+, further improving the anti-mould performance of bamboo materials. The dispersibility of ZnO nanoparticles in the ACQ solution was studied by an orthogonal test. The loss rates of Cu2+ in the bamboo specimens were measured. The results indicate that the incorporation of ZnO nanoparticles helps to mitigate Cu2+ leaching and further enhance the antibacterial properties of the bamboo specimens.

Solution-Processed Bilayered ZnO Electron Transport Layer for Efficient Inverted Non-Fullerene Organic Solar Cells

Organic solar cells (OSCs) are becoming increasingly popular in the scientific community because of their many desirable properties. These features include solution processability, low weight, low cost, and the ability to process on a wide scale using roll-to-roll technology. Enhancing the efficiency of photovoltaic systems, particularly high-performance OSCs, requires study into not only material design but also interface engineering. This study demonstrated that two different types of OSCs based on the PTB7-Th:IEICO-4F and PM6:Y6 active layers use a ZnO bilayer electron transport layer (ETL). The ZnO bilayer ETL comprises a ZnO nanoparticle (ZnO NP) and a ZnO layer created from a sol-gel. The effect of incorporating ZnO NPs into the electron transport layer (ETL) was studied; in particular, the effects on the electrical, optical, and morphological properties of the initial ZnO ETL were analyzed. The ability of ZnO films to carry charges is improved by the addition of ZnO nanoparticles (NPs), which increase their conductivity. The bilayer structure had better crystallinity and a smoother film surface than the single-layer sol-gel ZnO ETL. This led to a consistent and strong interfacial connection between the photoactive layer and the electron transport layer (ETL). Therefore, inverted organic solar cells (OSCs) with PTB7-Th:IEICO-4F and PM6:Y6 as photoactive layers exhibit improved power conversion efficiency and other photovoltaic properties when using the bilayer technique.

Comparative Performance Analysis of Novel Single-Slope Conventional Solar Still and Solar Still with ZnO Water Nanofluids through Experimental Investigation

Aim: This research primary aim is to explore efficiency of utilizing ZnO nanoparticles in elevating the solar still productivity for purifying saltwater into freshwater. The study involves a comparison of the output of a solar still with and without the use of nanoparticles to assess the influence of ZnO nanoparticles on the still's performance. The results of this investigation are expected to contribute to the development of more sustainable techniques for converting seawater into freshwater. Material and Methods: Two sets of experiments were conducted in this research: Group 1, which utilized a conventional solar still without ZnO nanoparticles, and Group 2, which utilized a modified solar still containing ZnO nanoparticles. The study included a total of 40 samples, with 20 samples in each group. SPSS software was used to calculate the size of the samples. The data analysis was conducted using descriptive statistics to obtain the mean and standard deviation of the results. The data gathered from the experiments were analyzed using SPSS software. Results: The study found that the most effective systems for reducing the payback period for the still with ZnO nanofluids were up to almost 3 years. This duration is lower than that of the still with ordinary water, and they also outperform carbon nanotubes and other nanofluids. The mean amount of clean water produced by Group 1 and Group 2 was compared using an independent t-test sample. Using SPSS v26 statistical software an samplet test was conducted on the obtained results, and the significance was ensured from the obtained (two- tailed) test p value 0.000 (p< 0.05). Conclusion: The utilization of ZnO nanoparticles as an additive to the base fluid has led to a considerable improvement in the solar still's productivity. The addition of ZnO nanoparticles at a concentration of 0.3% has significantly increased the daily yield, evaporation, and condensation rates. This enhancement in performance can result in a boost of up to

The effect of ZnO nanoparticles addition to PMMA on surface contact angle and adhesion of Candida albicans

The effect of ZnO nanoparticles addition to PMMA on surface contact angle and adhesion of Candida albicans

Antibacterial Calcium Phosphate Coatings with Zinc Oxide Nanoparticles

Porous calcium phosphate coatings (C-P) with ZnO nanoparticles were obtained via the micro-arc oxidation method on a titanium substrate. ZnO nanoparticles were added to the C-P coatings to change the zeta potential and improve the coatings’ bioactivity and antibacterial properties. The samples with coatings were studied via scanning electron microscopy (SEM), X-ray diffraction, energy dispersive microanalysis, potentiodynamic polarization, and zeta potential measurement. The coatings modified with ZnO nanoparticles showed improved physical, electrochemical, and electrical properties, compared to the initial unmodified coatings. Modification with ZnO nanoparticles contributed to an increase in zeta potential from −60 mV to −53 mV. Functionalization of the coatings with ZnO nanoparticles allowed us to increase the anticorrosion characteristics by about 30%. The biological studies showed that the coatings had no cytotoxic effect on L929 fibroblast cells. The antibacterial activity of the coating rose by 99% after the addition of ZnO nanoparticles against the bacterium Staphylococcus aureus.

Antibacterial Activity Edible Coating of Jackfruit Seed Starch and Alginate Incorporated with ZnO Nanoparticles Applied to Cherry Tomatoes

Cherry tomatoes have many health benefits and have high economic value. However, cherry tomatoes are perishable and short lived. To protect and maintain the quality of cherry tomatoes, you can apply an edible coating. The materials used in this study were jackfruit seed starch, alginate, and ZnO nanoparticles. This study aims to determine the effect of edible coating on jackfruit seed starch and alginate incorporating ZnO nanoparticles applied to cherry tomatoes in terms of antibacterial activity and shelf life. Variations in the treatment in this study were edible coating materials for jackfruit seed starch and alginate, and the concentration of ZnO nanoparticles (0%; 5%; 10%; 15%). Antibacterial activity was analyzed against E. coli and S. aureus bacteria. The results showed that the edible coating of jackfruit seed starch with 10% and 15% ZnO nanoparticles incorporation was able to form an inhibition zone against E. coli bacteria, while the 5%, 10%, and 15% ZnO nanoparticle variations were able to form an inhibition zone against S bacteria. aureus. In edible coating alginate with 15% ZnO nanoparticles incorporation was able to form an inhibition zone against E. coli bacteria, whereas in all variations of ZnO nanoparticles it was able to form an inhibition zone against S. aureus bacteria. The addition of ZnO nanoparticles proved the formation of a larger bacterial inhibition zone compared to edible coatings without ZnO nanoparticles. The results also showed that cherry tomatoes coated with an edible coating of jackfruit seed starch and alginate with a variation of ZnO nanoparticles had a longer shelf life compared to cherry tomatoes that were not coated with an edible coating.

Antimicrobial effect of hydro-alcoholic extract of apple with and without zinc oxide nanoparticles on Streptococcus Mutans.

This study aimed to evaluate the antimicrobial effect of hydro-alcoholic extract of apple (Malus domestica Borkh. Vs.golab, with and without ZnO nanoparticles) on Streptococcus Mutans bacterium compared to 0.2% Chlorhexidine, Persica and suspension of ZnO nanoparticles. Study samples were examined in the groups of apple hydro-alcoholic extract with and without addition of ZnO nanoparticles, a positive control group (Chlorhexidine 0.2%, Persica and suspension of ZnO nanoparticles), and a negative control group (distilled water). In this experiment, a concentration of 500 PPM of ZnO nanoparticles with a diameter of 0.4 nm was used. Agar diffusion method was used to determine the Minimum Inhibitory Concentration (MIC) of apple hydro-alcoholic extract with and without adding ZnO nanoparticles. The concentrations used were 200, 100, 50 and 25 mg/ml. ANOVA statistical test was used to compare the average in the study groups. According to our results, hydro-alcoholic extract of apples alone had no effect on the target bacteria in any of the concentrations. In the group of apple hydro-alcoholic extract with ZnO nanoparticles, the mean inhibition zone was 13 mm at a concentration of 25 mg/ml. 0.2% Chlorhexidine, Persica and suspension of ZnO nanoparticles was observed with the mean inhibition zone of 20 mm, 16 mm and 15 mm, respectively. Hydro-alcoholic extract of apple with addition of ZnO nanoparticles in concentration of 25mg/ml, had growth inhibitory effect on Streptococcus Mutans, but it was not remarkably efficient in comparison with Chlorhexidine.

Cathodic electrophoretic deposited HA-rGO-ZnO ternary composite coatings on ZK60 magnesium alloy for enhanced corrosion stability

HA-rGO-ZnO ternary composite coatings were successfully prepared on ZK60 magnesium alloy using cathodic electrophoretic deposition method. XRD analysis proved the addition of ZnO nanoparticles induced a significantly reduced crystallinity in hydroxyapatite and the tensile strain values of HA-rGO-ZnO composite coatings gradually decreased as the content of ZnO increased. SEM analyses revealed that the HA and ZnO nanoparticles were anchored on rGO nanosheets and a closely-packed network of recrystallization needle-like ZnO and mineralization HA crystals was formed on the surface of HA-rGO-ZnO coated sample. The resulting composite coating exhibited a uniform and compact HA-rGO-16ZnO composite coating, with well adhered to the ZK60 magnesium alloy substrate. The HA-rGO-16ZnO coated sample exhibited the highest corrosion resistance with lowest icorr (1.12 × 10−6 A/cm2) and the highest Ecorr (−1.43 V/SCE) value when compared to HA-rGO-14ZnO and HA-rGO-18ZnO samples after immersion in a SBF for 10 min. Compared to HA-rGO-ZnO coated samples after 10 min of immersion in SBF, HA-rGO-ZnO coated samples after 3 days of immersion in SBF exhibited a remarkably improved corrosion resistance and rapid inducing of the apatite layer precipitated on the surface of the composite coatings. The microstructure and composition for the coated samples after 3 days of immersion in SBF also confirm that the presence of a apatite layer on the composite coatings. HA-rGO-18ZnO coated samples after 3 days of immersion in SBF showed the lowest icorr value, which indicating HA-rGO-18ZnO ternary composite coatings dramatically improved the formation ability of the apatite layer and led to an enhancement in the bioactivity. Accordingly, it is believed that the HA-rGO composite coating incorporated with ZnO will be a potential candidate for bone biomedical applications.

The Antibacterial Effect of the Films Coated with the Layers Based on Uncaria tomentosa and Formitopsis betulina Extracts and ZnO Nanoparticles and Their Influence on the Secondary Shelf-Life of Sliced Cooked Ham

Microbial surface contamination of the cooked ham sliced by shop assistants has an influence on its potential secondary shelf-life. Active packaging may be the solution. The first goal of the work was to obtain coatings based on Formitopsis betulina and Uncaria tomentosa extracts (separately), with the addition of nanoparticles of ZnO (as a synergetic agent to increase plant extracts’ antimicrobial effectiveness), that could be active against selected bacterial strains. Another aim of the work was to determine the influence of obtained active layers on microbial purity and texture of the samples. The results of the study demonstrated that the layers containing F. betulina or U. tomentosa extracts with the addition of ZnO nanoparticles inhibited Staphylococcus aureus, Bacillus atrophaeus, and Escherichia coli growth completely and decreased the number of Pseudomonas syringae cells. Analyzing microbial purity of sliced cooked ham portions after storage, it was observed that the active packaging based on U. tomentosa extracts had a greater influence on the total count than the coatings containing F. betulina extracts and that both active packaging materials affected the microbial purity of the cooked ham. Analyzing the textural parameter changes after 48 h of storage, a decrease in the gumminess, chewiness and cohesiveness values was noted, but only for the ham portions stored in bags covered with the coating based on U. tomentosa. The effectiveness of the active packaging on textural parameters after 96 h of storage was not noticed.

Effect of ZnO nanoparticles on physical, optical and radiation shielding properties of Bi2O3-B2O3-Cr2O3 glasses

With a composition (in mol %) of 29Bi2O3-70B2O3-(1-x)Cr2O3: xZnO, (where, x = 0, 0.5 and 1) three glass samples were prepared by melt-quenching process. Despite the addition of ZnO nanoparticles, the SEM- morphology studies showed that the synthesized samples were transparent glass-ceramics. XRD studies confirmed that ZnO nanoparticles were homogeneously distributed in the glassy phase. When ZnO nanoparticles were added, oxygen packing density (OPD) was observed to increase, whereas boron-boron separation (dB-B) gradually decreased. The Raman spectra demonstrated that there was transformation of primary glass forming units, [BO3] → [BO4] units from x = 0 to 1 mol% of ZnO nanoparticles in the composition. Two absorption bands (in blue and red regions) have been attributed to the d-d transitions of Cr3+ ions in octahedral symmetry sites. When ZnO nanoparticles were added in the composition, the bandgap (Eo) was found to increase, and the non-linear optical susceptibility (χ(3)) decreased. Various gamma ray shielding properties of the samples have been determined in the energy range of 1 keV–15 MeV with the help of the Windows based program EpiXS. The sample with highest concentration of ZnO nanoparticles in the composition showed better radiation shielding behaviour among the three samples.

Effect of shape of ZnO nanoparticle on electro-optic and dielectric properties of nematic liquid crystal

Properties of liquid crystal incorporated with various shapes of a nanomaterial are expected to show multifaceted behaviour as properties of nanomaterial are extremely dependent on its size and shape. In view of this, we have investigated the effect of shape of ZnO nanoparticle on electro-optic and dielectric properties of nematic liquid crystal (NLC), PCH5. Nanocomposites of 0.01 wt% ZnO nano- sphere, rods, and wires in NLC are prepared. The addition of ZnO nanoparticles to NLC leads to increase in the order parameter and reduction in threshold voltage, response time as well as ionic conductivity as compared to the pure NLC host. Dielectric permittivity measurements indicate nanoparticle induces short range order in isotropic phase. Dielectric measurements also show increase in order parameter in nanocomposites with 1D nanoparticles whereas negligible change is observed in nanocomposites with spherical nanoparticles in NLC in deep nematic range. The ATR-FTIR measurements support the enhancement in parallel correlation of dipole moments in ZnO nanocomposites as compared to pure NLC.

Active chitosan- poly (vinyl alcohol) film reinforced with zinc oxide nanoparticles for food packaging applications

Active packaging represents an innovative alternative to improve the quality of food and extend the shelf life of the product. The main aim of this research is to develop antibacterial films based on chitosan (Cs), polyvinyl alcohol (PVA), and zinc oxide nanoparticles (ZnONps) to find a solution of food deterioration due to the presence of pathogenic microorganisms. ZnONps were synthesized by green chemistry using the leaves extract of Petroselinum crispum. The films were fabricated with 0; 0.5; and 1% w/v of ZnONps using different proportions of Cs: PVA by the casting method. The mechanical, physicochemical, antimicrobial, and antifungal properties were assessed. Moreover, the influence of the Cs/PVA/ZnONps films in the conservation of the Isabella grape was analyzed (pH, titratable acidity, weight loss, total soluble solids, and decay rate) and it was compared to commercial coating and uncoated grapes. Results showed the increase in the content of PVA improved the mechanical properties and increased the water absorption. Besides, Young’s Module, and tensile strength of the films improved with ZnO nanoparticles addition. The antimicrobial activity of the nanocomposite films against Escherichia Coli was demonstrated. Finally, it was corroborated the nanocomposite films preserve the quality and extend the shelf life of Isabella grapes 6 days more than the commercial coating affirming their use in food packaging. To the best of our knowledge, no previous work related with the development of films based on Cs/PVA reinforced with ZnONPs has tested its application as fruits packaging, determining its effect on the ripening process through physic-chemical assays.

ZnO nanoparticle: production and use for particleboard improvement

The need for more technological products increases with nanomaterials as a viable proposal, presenting good results in many different industrial sectors, especially in wood panels. Particleboards are composites of wood that have been extensively studied, mainly in relation to the adhesives used in their manufacture, which have an influence on particleboard properties. Thus, as a way of improving these adhesives, zinc oxide nanoparticles were added, giving new properties to the particleboard. Thereby, the present work aimed to produce particleboard with the wood of Eucalyptus Urophila x Grandis hybrid and urea-formaldehyde adhesive with ZnO nanoparticles addition. The physical tests performed were density, moisture content, and thickness swelling. The mechanical tests performed were the modulus of elasticity, modulus of rupture, and bonding tests. The results obtained were submitted to statistical analysis and compared with the requirements standards, as well as with works found in the literature. The addition of zinc oxide nanoparticles did not exercise influence on mechanical tests; however, the physical properties were improved, mainly decreasing the thickness swelling, which is usually a problem for wood products.

Macrocyclic Compounds: Metal Oxide Particles Nanocomposite Thin Films Deposited by MAPLE.

Nanocomposite films based on macrocyclic compounds (zinc phthalocyanine (ZnPc) and 5,10,15,20-tetra(4-pyridyl) 21H,23H-porphyrin (TPyP)) and metal oxide nanoparticles (ZnO or CuO) were deposited by matrix-assisted pulsed laser evaporation (MAPLE). 1,4-dioxane was used as a solvent in the preparation of MAPLE targets that favor the deposition of films with a low roughness, which is a key feature for their integration in structures for optoelectronic applications. The influence of the addition of ZnO nanoparticles (~20 nm in size) or CuO nanoparticles (~5 nm in size) in the ZnPc:TPyP mixture and the impact of the added metal oxide amount on the properties of the obtained composite films were evaluated in comparison to a reference layer based only on an organic blend. Thus, in the case of nanocomposite films, the vibrational fingerprints of both organic compounds were identified in the infrared spectra, their specific strong absorption bands were observed in the UV-Vis spectra, and a quenching of the TPyP emission band was visible in the photoluminescence spectra. The morphological analysis evidenced agglomerated particles on the composite film surface, but their presence has no significant impact on the roughness of the MAPLE deposited layers. The current density-voltage (J-V) characteristics of the structures based on the nanocomposite films deposited by MAPLE revealed the critical role played by the layer composition and component ratio, an improvement in the electrical parameters values being achieved only for the films with a certain type and optimum amount of metal oxide nanoparticles.

Dimensions of Hybrid and Nanohybrid Mouthguards for Mixed Martial Arts Fighters-Evaluation of a New Method of Fabrication.

Ethylene vinyl acetate mouthguards are the most often used custom protective intraoral appliances by combat sports practitioners. However, due to the difficulties in maintaining the hygiene of such mouthguards and thinning during fabrication, resulting in difficulty in predicting final dimensions, they may not be the optimal solution. The aim of this research was to evaluate an innovative method of mouthguard formation using intraoral modeling of the mouthguard pattern, hybrid acrylic material, and the addition of ZnO nanoparticles. Seventeen mouthguards patterns and 34 custom mouthguards were evaluated: 17 hybrid and 17 nanohybrid. A total of 1122 measurements were performed: each mouthguard and pattern was measured at 22 points. Statistical analyses were performed with the use of IBM® SPSS® Statistics 27.0.0 software (IBM, Armonk, NY USA). The mean thickness of the patterns and mouthguards at all labial areas of central incisors were between 4.65 and 4.80 mm. The thickness at the buccal surface of the first molar was between 3.71 and 4 mm, and at the occlusal surface between 3.40 and 3.56 mm in the cusp area. All measurements of hybrid and nanohybrid mouthguards were strongly and highly correlated with the measurements of the mouthguard patterns. Hybrid and nanohybrid mouthguards are an advantageous alternative to thermoformed custom appliances.