This work presents the evaluation of iron oxide nanoparticles obtained from the aqueous extract of Eucalyptus grandis. Twenty-three experiments were carried out where the synthesis of nanoparticles was performed by using the aqueous extract together with salts of iron (II) chloride tetrahydrate and iron (III) chloride hexahydrate. A characterization was carried out by IR, TEM and BET, where bands were presented at 3,440.77, 1,559.26 and 445.31 cm⁻¹, indicating the presence of iron oxide nanoparticles. A relatively high monodispersity was evidenced with particles around 9 nm. By means of BET analysis it was found to present a surface area of 131.897 m²/g. Obtaining nanoparticles by this green method presents yield values of 98%, with application in nanotechnology, biomedicine, environmental treatment, among others, making them highly versatile and their production cost is relatively low.

Disease epidemics may spread quickly and easily throughout nations and continents in our current global environment, having a devastating effect on public health and the world economy. There are over 513 million people worldwide who have been infected, and more than 6.2 million have died due to SARS-CoV-2. There are treatments but no cures for most viruses. Nevertheless, the spread of viruses can be limited by introducing antiviral coatings on public area surfaces and personal protective equipment (e.g., face masks). This work aims to fabricate a polymer-based coating with acrylic resin as a binder that possesses great antiviral activity against the Feline coronavirus (FCov). The chosen polymer, polyethylene glycol (PEG), is used as an antiviral agent because it contains “green” chemistry benefits such as non-toxicity, being inexpensive, readily recyclable, safe, natural, non-flammable, biocompatible, and biodegradable. The PEG/acrylic coating systems of different weight percentages were coated on the glass substrates by the spray-coating method and cured at room temperature for 24 hours. The developed PEG/acrylic coating system that contains 20 wt% of PEG exhibits the highest anti-viral activities (99.9% against FCov) compared to the other weight percentages. From this study, it has been observed that the hydrophilicity of the coating plays an important role in its antiviral activity. The developed coating has a hydrophilic property, in which the contact angle was measured at 83.28 ± 0.5°. The FTIR reveals that there are no existing toxic components or new components contained in the coating samples.

To investigate the possible role of arbuscular mycrrhizal fungi (AMF) in alleviating the negative effects of salinity on Stevia rebaudiana (Bert.), the regenerated plantlets in tissue culture was transferred to pots in greenhouse and inoculated with Glomus intraradices. Salinity caused a significant decrease in chlorophyll content, photosynthesis efficiency and enhanced the electrolyte leakage. The use of AMF in salt –affected plants resulted in improved all above mentioned characteristics. Hydrogen peroxide and malondialdehyde (MDA) contents increased in salt stressed plants while a reduction was observed due to AMF inoculation. CAT activity showed a significant increase up to 2 g/l and then followed by decline at 5 g/l NaCl in both AMF and non-AMF treated stevia, however, AMF inoculated plants maintained lower CAT activity at all salinity levels (2 and 5 g/l). Enhanced POX activities in salt- treated stevia plants were decreased by inoculation of plants with AMF. The addition of NaCl to stevia plants also resulted in an enhanced activity of SOD whilst, AMF plants maintained higher SOD activity at all salinity levels than those of non-AMF inoculated plants. AMF inoculation was capable of alleviating the damage caused by salinity on stevia plants by reducing oxidative stress and improving photosynthesis efficiency. 

The electrospinning precursor solution was prepared by dissolving polyvinyl pyrrolidone as template, tetrabutyl titanate as titanium source, and acetic acid as inhibitor. The TiO₂ nanofilms were prepared by precursor solution electrospinning and subsequent calcination. Thermal gravimetric analysis (TG), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize and analyze the samples. The influence of technological parameters on spinning fiber morphology was also studied. The results indicate that the TiO₂ nanofibers morphology is good when the parameters are as follows: voltage 1.4×10⁴ V，spinning distance 0.2 m，translational velocity 2.5×10^-3 m·s^-1, flow rate 3×10^-4 m·s^-1, and needle diameter 3×10^-4 m. The diameter of the fibers is about 150 nm. With the 1×10^-4 mol·L^-1 methylene blue solution used as simulated degradation target, the degradation rate is 95.8% after 180 minutes.

In the present work, a series of butyl methacrylate/1-hexene copolymers were synthesized, and their efficiency as viscosity index improvers, pour point depressants, and shear stabilizers of lube oil was investigated. The effect of 1-hexene molar ratio, type, and concentration of Lewis acids on the incorporation of 1-hexene into the copolymer backbone was investigated. The successful synthesis of the copolymers was confirmed through FTIR and 1H NMR spectroscopy. Results obtained from quantitative 1H NMR and GPC revealed that an increase in the molar ratio of 1-hexene to butyl methacrylate, along with concentration of Lewis acids led to an increase in 1-hexene incorporation and a reduction in Mn and Ð. Similar trends were observed when the Lewis acid changed from AlCl₃ to organometallic acids. The maximum 1-hexene incorporation (26.4%) was achieved for sample BHY3, with a [1-hexene/BMA] ratio of 4 mol% and a [Yb(OTf)₃/BMA] ratio of 2.5 mol%. Evaluation of the synthesized copolymers as lube oil additives demonstrated that the viscosity index was more significantly influenced by samples with higher molecular weight. Sample BHA13 represents maximum VI of 137. The copolymer containing Yb(OTf)₃ as a catalyst exhibited superior efficiency as a pour point depressant. Furthermore, sample BHY3 showed the lowest shear stability index (6.4).