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There has been an increasing number of studies in magnetic nanoparticles with auspicious applications in medicine. Among the oxides of magnetic nanoparticles, iron oxide has emerged as an indispensable tool in nanotechnology, particularly bio-nanotechnology. This is attributed to its exceptional properties such as size, shape, magnetism, and biocompatibility. In this review, iron oxide nanoparticles were exploited in different model organisms ranging from prokaryotes to eukaryotes, elucidating their cellular functions relative to their antibacterial activity, drug delivery, and toxicity.

The Hydrophilic-Lipophilic Difference (HLD) model can be described by additive contributions accounting for the effect of the oil and surfactant nature, temperature, ionic strength, and so on. The first step to build an HLD framework for a surfactant class is to have Winsor III phase equilibria in a restricted range of formulation variables. In this respect, anionic and nonionic surfactants are well suited for an HLD study. On the contrary, it is difficult achieve for pure cationic surfactant Winsor III phase equilibria without the addition of alcohols and this has precluded the extension of the HLD to cationic surfactants.

In the present contribution, we first propose a system based on a blend of single-tailed and double-tailed cationic surfactant to study the oil contribution, and then we afforded the determination of the surfactant contribution trough an experimental approach (the “HLD-titration”) that is especially tailored for systems displaying a wide range of existence of Winsor III phase equilibria.

HLD-titration results confirmed the ionic strength contribution to HLD as a logarithmic function of salinity for cationic-based microemulsions similarly to anionic ones. However, the oil carbon number contribution is almost four-fold larger (k ​= ​0.7 ​± ​0.1) with respect to anionic surfactants. A clearing point was observed in correspondence of the Winsor III phase equilibria under stirring. This approach allows us the determination of the so-called characteristic curvature (Cc), i.e. the term describing the surfactant nature contribution to the film curvature, of the cationic surfactant. Finally, the method was adopted to determine Cc values of 7 quaternary ammonium surfactants differing in the polar heads nature and further three amine oxide surfactant at pH ​= ​1 where they are protonated.

Hypothesis

High molecular weight polymers are widely used in oilfield applications, such as in chemical enhanced oil recovery (cEOR) technique for hydrocarbon recovery. However, during flow in a porous rock, polymer retention is usually a major challenge, as it may result in the decrease of polymer concentration or lead to plugging of pores with significant permeability reduction and injectivity loss. Hence, an understanding of the retention mechanisms will have a profound effect in optimizing the process of polymer flooding, in particular, for carbonate rocks, which hold more than half of the world's oil reserves. Therefore, in this study, the retention of hydrolysed polyacrylamide (HPAM) polymer, a commonly used chemical for EOR, is investigated during flow in Estaillades carbonate rock.

Experiments

A novel approach of investigating HPAM retention in Estaillades carbonate rock was carried out using Atomic force microscopy (AFM). Since Estaillades carbonate rock is ∼98% calcite, HPAM retention was first characterised on a cleaved flat calcite mineral surface after immersing in HPAM solution. Afterwards, HPAM was flooded in Estaillades carbonate to observe the effect of flow dynamics on the retention mechanisms.

Findings

We find that the dominant mechanism for retention of HPAM on calcite after fluid immersion is polymer adsorption, which we believe is driven by the electrostatic interaction between the calcite surface and the solution. The thickness of the adsorbed layer on calcite is beyond 3 ​nm suggesting it is not adsorbed only flat on the surface. Different types of adsorbed layers were formed representing trains, and the more extended loops or tails with the largest polymer layer thickness about 35 ​nm, representing the longer loops or tails. Layers of this thickness will begin to impair the permeability of the rock. However, in Estaillades, thicker adsorbed layers are observed in different regions of the rock surface ranging between 50 and 350 ​nm. We suggest that this is due to either mechanical entrapment and/or polymer entanglement during flow in Estaillades carbonate rock, which will cause the major permeability impairment in porous rocks.

Nanoparticle drug delivery systems encounter many biological barriers, such as the extracellular matrix and mucus gels, that they must bypass to gain access to target cells. A design parameter that has recently gained attention is nanoparticle shape, as it has been shown elongated rod–shaped nanoparticles achieve higher diffusion rates through biological gels. However, the optimal dimensions of rod-shaped nanoparticles to enhance this effect has yet to be established. To systematically approach this, rod-shaped nanoparticles were synthesized by mechanically stretching 100 ​nm, 200 ​nm, and 500 ​nm spherical nanoparticles. Transmission electron microscopy confirmed this procedure yields a significant fraction of elongated rods and remaining spheres could be removed by centrifugation. Fluorescent microscopy and multiple particle tracking analysis was then used to characterize rod-shaped and spherical nanoparticle diffusion in MaxGel®, a model extracellular matrix hydrogel. When dispersed in MaxGel, we found rod-shaped nanoparticles exhibited the greatest enhancement in diffusion rate when their length far exceeds the average hydrogel network size. These results further establish the importance of shape as a design criterion to improve nanoparticle-based drug delivery systems.

Metal oxide composites containing nanostructured carbons have been extensively researched to overcome difficulties such as low intrinsic electronic conductivity, significant irreversible capacity loss, and poor coulombic efficiency in lithium-ion batteries (LIBs). A time-efficient microwave autoclave synthesis technique was approached to fuse V₂O₅ to MWCNT strands. V2O5/MWCNT is a hybrid nanoparticle with crucial features for the electrode needed for a supercapacitor that has been investigated and reported. Due to X-ray diffraction (XRD) peak investigation, the nanoparticles' phase structure, space group, and strain($\epsilon$) have been determined. The particle size was calculated in Debye-Scherrer, modified Scherrer, and uniform deformation modeling (UDM) modes. The interaction between light photons and electrons is thoroughly addressed using UV–Vis technology. Optical constants like refractive index (n), absorption coefficient ($\alpha$), and destructive coefficient (k) is addressed as a result of this. Nanoparticles' dielectric function (${\epsilon }_r$and ${\epsilon }_i$), and direct bandgap have also been reported. Along with V₂O₅/MWCNT's strong Photoluminescence (PL) emission, interpretation of unique optical properties and considerable potential for practical applications have been intensively studied. V₂O₅/MWCNT is confirmed by data acquired by Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) for vanadium, oxygen, and carbon. The formation of nanoparticles with the dimensions of V2O5/MWCNT is proven by Scanning Electron Microscopic (SEM) micrographic imagery. A Cyclic Voltammetry (CV) analyzer measures the material's highest specific capacity when exposed to electrochemical action, 632 Fg-1. The median power density (E) is predicted to be 146 Whkg-1, and the power density (P) is 1.52 ​kW kg-1 in the Galvanostatic Charge/Discharging (GCD) rating. These values are beneficial for describing the capabilities of supercapacitors.

One-step emulsification approaches enable prevention of the loss of emulsion droplets associated with two-step emulsification approaches. Stimuli-responsive amphiphilic block copolymers, emulsifiers, and nanoparticles that are responsive to changes in the temperature, pH, presence of CO₂, or presence of salts, can eliminate the requirement for two hydrophilic and lipophilic emulsifiers in the emulsion system. The amphiphilic block copolymers prepared from naturally occurring amino acids and proteins enable targeted delivery of drugs and nutraceuticals with high cellular uptake. Likewise, the presence of impurities, such as salts and redox reactions driven by the presence of iodine, can result in spontaneous emulsification and formation of double emulsions. This timely review focuses on the application of double emulsions for delivery of drugs and nutraceuticals and will provide insights to scientists in the pharmaceutical industry or food nutritionists who consider fortification of food products with micronutrients.

Periodic Density Functional Theory calculations reveal the potential application of 10 imidazole based N-heterocyclic carbenes (NHCs) to behave as “molecular corks” for hydrogen storage on single atom alloys, comprised of Pd/Cu(111) or Pt/Cu(111). Calculations show that functionalizing the NHC with different electron withdrawing/donating functional groups results in different binding energies of the NHC with the alloy surfaces. The results are compared to DFT calculations of carbon monoxide bound to these alloys. The Huynh electronic parameter is calculated for several simple imidazole NHCs to gauge σ-donor ability, while Se-NMR and P NMR calculations of selenourea derivatives and carbene-phosphinidene adducts, respectively, have been utilized to gauge π-acidity of the NHCs. It is demonstrated that consideration of both σ and π donating/accepting ability must be considered when predicting the surface-adsorbate binding energy. It was found that electron withdrawing groups tend to weaken the NHC-surface interaction while electron donating substituents tend to strengthen the interaction.

In this research, new green synthesized cow urine silver nanoparticles (CoUSiN particles) were accomplished by using cow urine as a reducing and capping agent. The cow urine silver nanoparticles have been marked by UV–Visible spectroscopy, X-ray diffraction, Fourier Transformer Infrared spectroscopy, Scanning Electron Microscopy, and Transmission Electron Microscopy. The size of the CoUSiN particles had probed by using a dynamic light scattering method and was determined to be 47.8 ​nm. Further, CoUSiN particles evidenced biocidal venture against Escherichia coli and methicillin-resistant Staphylococcus aureus through cell wall destruction and membrane poring. The SEM established the absolute biocidal sheath destabilization of Escherichia coli and whereas the cyclic voltammetry (CV) bolstered the membrane poring mechanism on methicillin-resistant Staphylococcus aureus. Further, the blood congenial nature of CoUSiN particles fortified that it can be a promising candidate to heal epizootic diseases. The inquiry infers that the CoUSiN particles incorporated adopting a simple, inexpensive, eco-friendly modus using cow urine as a reducing agent.

The anodic dissolution of the high-grade nickel matte in the sulfuric acid solution was investigated at the dynamic potential and potentiostatic polarizations, and the solid products on the surface of the matte at various polarized potentials were characterized by optical microscope, scanning electron microscope and Raman spectroscopy in order to understand the passivation mechanism for the anodic dissolution of nickel matte. The results show that the oxidation dissolution activity of nickel and copper sulfides existing in the matte during the anodic dissolution decreases in the order Cu₂S ​> ​Ni₃S₂ ​> ​NiS ​> ​CuS. When the anodic polarization potential is increasing to 1.2 ​V vs. SCE, the solid product for the oxidation of Cu₂S is composed of CuS, which forms a compact layer with fine cracks covering the surface and hinders the anodic dissolution further of Cu₂S underneath. While, at the same polarization potential, Ni₃S₂ in the matte can be anodically dissolved to form Ni²⁺ and elemental sulfur, and the solid product layer composing of sulfur and NiS is porous with coarse cracks, and has adverse effect on the anodic dissolution of Ni₃S₂ in the nickel matte.

Physicochemical properties of lipid monolayer depend on its composition where a blend of lipids exhibit superior behaviour than the individual component. Surface pressure (π) – area (A) isotherms of mixed monolayer (PC_mix) formed by dipalmitoylphosphatidylcholine (DPPC), palmitoleylphosphatidylcholine (POPC), soyphosphatidylcholine (SPC) and hydrogenated soy phosphatidylcholine (HSPC) in combination with 30 mole % cholesterol (Chol) were obtained by using Langmuir trough. Effects of dipalmitoylphosphatidyethanolamine (DPPE) on its mutual miscibility at the air-water interface with DPPC ​+ ​Chol, POPC ​+ ​Chol, HSPC ​+ ​Chol and SPC ​+ ​Chol were also investigated separately, followed by studying the effects of DPPE and dipalmitoylphosphatidylglycerol (DPPG) to PC_mix ​+ ​Chol and PC_mix ​+ ​DPPE ​+ ​Chol respectively. Lift-off area, minimum molecular area, excess molecular area, collapse pressure, Gibbs free energy of interfacial mixing, compressibility modulii values were evaluated by analyzing the isotherms. Deviations from the ideal mixing behaviours were dependent on the composition of the lipid blends. Surface dilatational rheology studies could assess monolayer elasticity, whereas the film morphologies were analysed by Brewster angle microscopic (BAM) studies. DPPC induced formation of condensed monolayer, whereas film rigidity was increased with the incorporation of DPPE and DPPG into mixed systems. Interactions among the lipid components of the investigated mixed systems were thoroughly discussed from the point of view of polar head and acyl chain saturation and obtained results follow the sequence: PC_mix ​+ ​DPPE ​+ ​DPPG ​+ ​Chol ​> ​PC_mix ​+ ​DPPE ​+ ​Chol ​> ​individual PC ​+ ​DPPE ​+ ​Chol which could be translated into the bilayer studies. Such investigation of mixed lipid is important for class of its own composition and combined results are expected to contribute in better understanding the interaction of selected lipid in proposed blend.