Sustained delivery of olanzapine from sunflower oil‐based polyol‐urethane nanoparticles synthesised through a cyclic carbonate ring‐opening reaction

The forefront horizon of biomedical investigations in recent decades is parcelling‐up and delivery of drugs to achieve controlled/targeted release. In this regard, developing green‐based delivery systems for a spatiotemporal controlling therapeutic agent have drawn a lot of attention. A facile route based on cyclic carbonate ring‐opening reaction has been utilised to synthesise a bio‐based polyol‐containing urethane bond [polyol‐urethane (POU)] as a nanoparticulate drug delivery system of olanzapine in order to enhance its bioavailability. After characterisation, the nanoparticles were also estimated for in vitro release, toxicity, and pharmacokinetic studies. As olanzapine has shown poor bioavailability and permeability in the brain, the sustained release of olanzapine from the designed carriers could enhance pharmacokinetic effectiveness. POU in the aqueous solution formed micelles with a hydrophobic core and embedded olanzapine under the influence of its hydrophobic nature. Drug release from the nanoparticles (90 ± 0.43 nm in diameter) indicated a specific pattern with initial burst release, and then a sustained release behaviour (82 ± 3% after 168 h), by the Higuchi‐based release mechanism. Pharmacokinetics assessments of POU‐olanzapine nanoparticles were carried in male Wistar rats through intravenous administration. The obtained results paved a way to introduce the POU as an efficient platform to enhance the bioavailability of olanzapine in therapeutic methods.Inspec keywords: hydrophobicity, nanomedicine, nanofabrication, nanoparticles, drug delivery systems, biomedical materials, polymers, brainOther keywords: cyclic carbonate ring‐opening reaction, nanoparticulate drug delivery system, bioavailability, drug release, initial burst release, Higuchi‐based release mechanism, POU‐olanzapine nanoparticles, sunflower oil‐based polyol‐urethane nanoparticles, forefront horizon, biomedical investigations, green‐based delivery systems, spatiotemporal controlling therapeutic agent, bio‐based polyol‐containing urethane bond, polyol‐urethane, toxicity, pharmacokinetic studies, olanzapine, aqueous solution, micelles, hydrophobic core, Pharmacokinetics, male Wistar rats, brain     

Photocatalytic activity of TiO2-capped ZnO nanoparticles

Using a combined hydrothermal and sol–gel route, TiO₂ -capped ZnO nanoparticles with an average size of 60 nm were prepared. The titania shell was amorphous with a thickness of ~10 nm. Formation of Zn₂TiO₄ phase at higher calcination temperature was noticed. Effects of Ti/Zn molar ratio and coating time on the thickness of TiO₂ shell and the photoactivity of the particles for decolorization of Methylene Blue (MB) under UV lamp irradiation (3 mW/cm²) were investigated. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, fourier-transform infrared spectrometry (FTIR), diffuse reflectance spectroscopy (DLS), and atomic absorption spectroscopy. Analysis of the photoactivity results according to Langmuir–Hinshelwood model revealed a two-step decolorization process with a high kinetics rate at the early stage followed by a slower step. The capped nanoparticles synthesized under specific conditions exhibited higher photodecolorization yield and faster kinetics in comparison to the uncoated ZnO and P25-Degussa TiO₂ nanoparticles.     

Transforming Results from Model to Prototype of Concrete Gravity Dams Using Neural Networks

A new method using neural networks for the transformation of results from dam models to prototypes has been proposed and validated through application to Koyna and Pine-Flat Dams, which have also been investigated by other researchers. The neural network has been called the neurotransformer. The common method for building a suitable experimental model for a dam to be tested on a shaking table is linear dimensional analysis or simply linear scaling (LS). However, because LS is theoretically applicable to linear systems, it generally provides imprecise results of transformation for extreme loading when the model or the prototype experiences noticeable nonlinearity. In this paper, it is shown through numerical simulation of the dynamic behaviour of Koyna Dam and its 1/50 model under strong earthquakes, which cause nonlinear behavior in both the dam and its model, that transformation by neural networks is considerably more precise than LS. To show the method can also be applied to other dams, the same procedure was successfully applied to Pine-Flat Dam; again, the neurotransformer outperformed the LS.     

Interplay between Field Measurements and Soil Behavior for Capturing Supported Excavation Response

Instruments are installed during the construction of urban excavations to monitor ground response at discrete locations to various construction activities, to verify design assumptions and to effectively apply the observational approach. Inverse analysis approaches are often used to develop improved soil models suitable for representing soil response during excavation from these measurements. We propose that through the integration of inverse analysis and instrument measurements, it is possible to provide information on excavation performance at locations where no instrumentation is available. Therefore, this study examines the relationship between various instruments typically used on an excavation project and the quality of information that can be extracted for excavation modeling. A synthetically generated set of instrument measurements that include inclinometers, surface settlement points, extensometers, heave gauges, piezometers, and strain gauges, using an idealized soil profile are initially used. The analyses show that in addition to the measurements of lateral wall deflections and surface settlement, inclinometers placed some distance behind the wall and measured forces in the struts significantly improve the quality of the extracted soil behavior. These findings are further demonstrated with a well instrumented deep excavation case study in Taipei. The inclinometers at the wall and at farther distance from the wall are used to extract the soil behavior. The extracted soil model used in a numerical analysis provides a good prediction of excavation behavior elsewhere around the excavation including surface settlements.     

Development of novel hybrid nanocomposites based on natural biodegradable polymer–montmorillonite/polyaniline: preparation and characterization

The problems with non-degradable materials in different applications have led to an interest in materials based on bionanocomposites. In this study, polymer–montmorillonite nanocomposites based on natural polymers (chitosan, alginate, gelatin and starch) and montmorillonite (MMT) were prepared using solution intercalation method. Then hybrid nanocomposites were synthesized by chemical oxidative polymerization of aniline in the presence of polymer–MMT nanocomposites. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) were employed to characterize the nanocomposites. FT-IR confirmed the successful preparation of hybrid nanocomposites. From the XRD results, intercalation of the MMT platelets in the matrix of polymers was examined. Further investigation by TEM images showed a mixed intercalated and flocculated structure for nanocomposites. Moreover, the TGA results showed improved thermal stability for the nanocomposites. The results presented in this study showed the feasibility of using these hybrid nanocomposites with improved properties in wide range of applications.     

Effects of dopant,coagulant, and reinforcing nanofiller on mechanical and electrical properties of wet-spun polyaniline nanocomposite fibers

This paper describes the application of Taguchi experimental design to study the simultaneous effects of the dopant, the coagulant, and multiwalled carbon nanotubes (MWCNTs) used as reinforcing filler on the properties (tensile strength and electrical conductivity) of polyaniline (PANI) nanocomposite fibers produced via a wet spinning process. The MWCNT content was found to be the most significant factor, accounting for 72.8 % of the total contribution of the three selected parameters to the tensile strength. The dopant contributed 17.6 %, while the coagulant had a negligible effect and was therefore pooled. MWCNT content provided the maximum contribution of 98 % to the electrical conductivity, whereas the dopant and the coagulant had negligible effects, with contributions of 0.021 % and 0.247 %, respectively. A scanning electron microscope (SEM) and a tapping-mode atomic force microscope (AFM) were employed to study the morphology of the fibers. The electrochemical and pseudocapacitive properties of the fibers were investigated using cyclic voltammetry (CV). The PANI-AMPSA-MWCNT presented a specific capacitance value of 12.8 F cm^?2. The thermal characteristics of the nanocomposite fibers were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Elemental analysis of the fibers showed a high degree of doping: about 47–55 %.     

Forward osmosis water desalination: Fabrication of graphene oxide-polyamide/polysulfone thin-film nanocomposite membrane with high water flux and low reverse salt diffusion

This paper investigates the synthesis of graphene oxide (GO)-incorporated polyamide thin-film nanocomposite (TFN) membranes on polysulfone substrate for forward osmosis applications. The GO nanosheets were embedded into polyamide layer using different concentrations (0.05?0.2 wt%). The results represented the alteration of polyamide surface by GO nanosheets and enhancing the surface hydrophilicity by increasing the GO loading. The results showed that the water flux for 0.1 wt% GO embedded nanocomposite (TFN) membrane was 34.7 L/m² h, representing 90% improvement compared to the thin-film composite, while the salt reverse diffusion was reduced up to 39%.     

Self-healing waterborne polyurethane coating by pH-dependent triggered-release mechanism

In this study, effect of high-loaded silica capsules with corrosion inhibitor on thermal degradation and self-healing properties of waterborne polyurethane (WPU) was investigated. Silica capsules were synthesized using an oil in water (O/W) microemulsion and WPU was prepared via the prepolymer method. Assembled capsules demonstrated pH dependent release of their core. Incorporating silica capsule as an inorganic component resulted to improve thermal and barrier properties of WPU coatings. WPU coating with 1% silica capsules demonstrated better barrier quality in corrosive media and adding more than that resulted a rapid deterioration in barrier properties. Furthermore, such coatings possess an excellent adhesive strength with steel substrate. Electrochemical impedance spectroscopy was used in corrosion monitoring and healing procedure. Moreover, capsule morphology and thermal degradation of the WPU coating has been investigated separately by scanning electron microscopy and thermal gravimetric analysis. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47082.     

Polyamidoamines based on castor oil-styrene co-oligomer/triethylenetetramine as curing agents in high-performance epoxy coatings

Polyamidoamines (PAMAMs) based on castor oil-styrene co-oligomer and triethylenetetramine (TETA) or benzylated TETA were synthesized and diluted with an amide-like diluent (EFA). The intermediates and products structures were characterized using FT-IR, ¹H NMR, gel permeation chromatography, and scanning electron microscopy. The diluted PAMAMs types were used as the curing agents of the epoxy resin to produce the modified coatings. The mechanical, chemical, and visual properties of the epoxy coatings obtained by commercial hardeners compared to the modified coatings. The modified coatings were transparent, and had humidity resistance higher than the commercial coatings, at 15°C and 80% relative humidity. The modified coatings were obtained with the lowest surface defects and improved mechanical properties such as Izod impact resistance, tensile strength, and the pull-off adhesion (3.3–4.8 kJ m⁻², 42.2–54.5 MPa and 3.0–3.5 MPa) relative to the commercial coatings (1.1–3.0 kJ m⁻², 28.7–39.9 MPa and 1.4–2.1 MPa), respectively. Moreover, in spite of the commercial coatings, the modified coatings were cost-effective and showed the behaviors of appropriate self-healing and chemical resistance.     

Application of polymer‐coated quartz crystal microbalance (QCM) as a sensor for BTEX compounds vapors

A sensor based on the technique of a quartz crystal microbalance (QCM) was developed for the detection of organic vapors such as benzene, toluene, ethylbenzene, and xylenes (BTEX compounds). Detection was based on the adsorption of organic vapors on a thin layer of polydimethylsiloxane (PDMS) coated at the surface of AT‐cut gold‐coated quartz crystal electrodes. The frequency shifts due to the sorption of BTEX compounds were measured. Calibration graphs were constructed by plotting the frequency changes (ΔF/Hz) against the concentration of organic compounds. Using this method, the detection of these organic vapors was carried out at the ppm level. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1062–1066, 2001