A New Method for Preparation of Cellular Ceramics by Gelcasting Approach

This paper presents the results of a novel-processing route for fabricating highly cellular ceramics. The method is based on the generation of foam in two continuously stages: one, is the foaming of ceramic suspension by use foaming agent prior to the polymerization and other, is the evaporation of light organic solvent such as acetone, methanol and ethanol during polymerization because of exothermic reaction of gelation. The resulting ceramic foams consisted of a highly interconnected network of cells with densities as low as 0.2 g/cm3. The distribution of cell size was dependent both on the density of the specimen produced and on the time for polymerization onset. The size ranged from approximately 50 to 1000 μm. Enlargement of cell size to achieve materials of high permeability was possible through expansion of the foam via pressure reduction before polymerization

Flame Retardant Effects of Nano-Clinoptilolite on AcrylonitrileButadiene-Styrene (ABS) Nano-Composite

In recent years, intumescent technology has found a place in polymer science as a method of providing flame retardance to polymeric materials. On heating, fire-retardant intumescent material restricts the action of the heat flux or flame. The proposed mechanism is based on charred layer acting as physical barrier, which slows down heat and mass transfer between the gas and the condensed phases. In this paper, the flammability of intumescent fire-retardant acrylonitrile-butadiene-styrene (ABS) matrix composites consisting of hydromagnesite (HMg) as an acid source and blowing agent, pentaerythritol (PER) as a carbonisation agent and natural zeolite (clinoptilolite rich, Kansar Shargh) as a synergistic agent were examined. The flammability of composites was characterized by limiting oxygen index (LOI) measurement and horizontal burning tests. A synergistic effect in flame retardancy was observed when natural zeolites were used in combination with HMg and PER

Effective Methylene Blue Removal from Aqueous Solutions using PVA/Chitosan Electrospun Nanofiber Modified with CeAlO3 Nanoparticles

This research work aims to investigate the sorption characteristic of synthesized Poly (vinyl alcohol)/Chitosan nanofiber mats modified with aluminum-cerium spinel oxide (CeAlO3) nanoparticles for methylene blue (MB) removal from aqueous solutions. The sorption is carried out by a batch technique. The structural characterization of this nanocomposite was performed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD). Scanning electron microscopy (SEM) results showed uniform net and improved nanofibers with diameters ranging about 420 and 450 nm, respectively. The optimum conditions of MB removal onto modified PVA/CS nanofibers were found to be: pH 10, contact time 45 min, and 0.01 g of adsorbent in 400 ml in aqueous solution. Furthermore, the experimental adsorption data were in excellent agreement with the pseudo-second-order kinetics. The experimental results showed that there is a good correlation between the obtained data and the adsorption isotherm in the concentration range studied (400-600 mg/l). The results revealed that the maximum adsorption capacity of MB was 817.81 and 714.61 mg/g onto improved and net nanofibers, respectively

Investigation of kinetic properties of hydrolyzed polyacrylamide crosslinked by transient metal ligand

669-672The aim of this study was to investigate the kinetic properties of hydrolyzed polyacrylamide gel. The hydrolyzed polyacrylamide was synthesized by free radical mechanism. The optimum molecular weight for the gel preparation was then obtained after examination of various factors such as average molecular weight, initiator concentration and reaction time in the gelation process. The main interaction which creates supramolecular gel is metal ligand coordination between carboxylate groups and chromium ions, and amide groups. These bonds were confirmed by FTIR and UV-Visible spectra techniques. Furthermore, the XRD showed crystalline structure in the gel

A novel method for <i>in situ</i> encapsulation of curcumin in magnetite-silica core-shell nanocomposites:A multifunctional platform for controlled drug delivery and magnetic hyperthermia therapy

In this study, we developed a novel strategy for in situ encapsulation of hydrophobic drugs such as curcumin into the magnetite-mesoporous silica nanocomposites with a core-shell structure. In the proposed method, a modified reverse microemulsion system was used for silica formation on the surface of curcumin-loaded Fe3O4 nanoparticles (Cur@Fe3O4 NPs) to render mesoporous silica-coated Cur@Fe3O4 NPs (SiO2/Cur@Fe3O4 NPs). The prepared SiO2/Cur@Fe3O4 NPs with a core-shell structure had a spherical shape with a mean particle size less than 100 nm. The heating efficacy of the prepared nanocomposites was examined for application in magnetic hyperthermia therapy by exposing them to different biological safe alternating magnetic fields. The maximum specific absorption rate (SAR) obtained by the prepared sample, was found to be 22.11 WgFe3O4−1at the magnetic field intensity of 28 kA m−1 and frequency of 120 kHz.. Also, the prepared nanocomposites exhibited a pH-responsive drug release behavior. The in vitro drug release studies showed that, only 8.9% of curcumin was releasedwas from SiO2/Cur@Fe3O4 NPs at pH 7.4, while about 40% of drug was released at pH 5.0, after 5 days. Moreover, the in vitro cytotoxicity analysis showed that, by encapsulation of curcumin in the prepared nanocomposites, the cytotoxicity of the drug was significantly increased against breast cancer MCF-7 cells, compared to the free drug, so that, at curcumin concentration of 40 μg mL−1, the viability of MCF-7 cells incubated with free curcumin was 62.0%, whereas by encapsulation of curcumin in SiO2/Cur@Fe3O4 NPs the viability was decreased to 26.7% (Pvalue ≤ 0.005)

Removal of Fluoride Ion from Aqueous Solution by Nanocomposite Hydrogel Based on Starch/Sodium Acrylate/Nano Aluminum Oxide

Determination of fluoride in drinking water has received increasing interest, due to its beneficial and detrimental effects on health. Contamination of drinking water by fluoride can cause potential hazards to human health. In recent years, considerable attention has been given to different methods for the removal of fluoride from drinking and waste waters. The aim of this research was to investigate the effect of nano composite hydrogel based on starch/sodium acrylate/aluminum oxide in reduction of fluoride concentration in drinking water and industrial waste water. In a batch system, the dynamic and equilibrium adsorption of fluoride ions were studied with respect to changes in determining parameters such as pH, contact time, initial fluoride concentration, starch/acrylic acid weight ratio and weight percent of nano aluminum oxide. The obtained equilibrium adsorption data were fitted with Langmuir and Freundlich models, as well as the kinetic data with pseudo-first order and pseudo- second order models. The results showed that optimum pH was found to be in the range of 5 to 7. Removal efficiency of fluoride was increased with decreases in initial concentration of fluoride. Sixty percent of initial value of fluoride solution was removed by nano composite hydrogel (4 wt% of nano aluminum oxide) at 240 min (initial fluoride concentration = 5 ppm, pH 6.8 and temperature = 25ºC). Under the same condition, the equilibrium adsorption of fluoride ions was 85% and 68% for initial solution concentration of 5 and 10 ppm, respectively. Adsorption isotherm data showed that the fluoride sorption followed the Langmuir model. Kinetics of sorption of fluoride onto nano composite hydrogel was described by pseudo-first order model

In Vitro Release of Glycyrrhiza Glabra Extract by a Gel-Based Microneedle Patch for Psoriasis Treatment

Microneedle patches are attractive drug delivery systems that give hope for treating skin disorders. In this study, to first fabricate a chitosan-based low-cost microneedle patch (MNP) using a CO2 laser cutter for in vitro purposes was tried and then the delivery and impact of Glycyrrhiza glabra extract (GgE) on the cell population by this microneedle was evaluated. Microscopic analysis, swelling, penetration, degradation, biocompatibility, and drug delivery were carried out to assess the patch’s performance. DAPI staining and acridine orange (AO) staining were performed to evaluate cell numbers. Based on the results, the MNs were conical and sharp enough (diameter: 400–500 μm, height: 700–900 μm). They showed notable swelling (2 folds) during 5 min and good degradability during 30 min, which can be considered a burst release. The MNP showed no cytotoxicity against fibroblast cell line L929. It also demonstrated good potential for GgE delivery. The results from AO and DAPI staining approved the reduction in the cell population after GgE delivery. To sum up, the fabricated MNP can be a useful recommendation for lab-scale studies. In addition, a GgE-loaded MNP can be a good remedy for skin disorders in which cell proliferation needs to be controlled