Sharif Digital Repository

In this work, a new type of flooding system, "worm-like micelles", in enhanced heavy oil recovery (EOR) has been introduced. Application of these types of surfactants, because of their intriguing and surprising behaviour, is attractive for EOR studies. Fundamental understanding of the sweep efficiencies as well as displacement mechanisms of this flooding system in heterogeneous systems especially for heavy oils remains a topic of debate in the literature. Worm-like micellar surfactant solutions are made up of highly flexible cylindrical aggregates. Such micellar solutions display high surface activity and high viscoelasticity, making them attractive in practical applications for EOR. In this... 

In recent years miscellaneous smart micro/nanosystems that respond to various exogenous/endogenous stimuli including temperature, magnetic/electric field, mechanical force, ultrasound/light irradiation, redox potentials, and biomolecule concentration have been developed for targeted delivery and release of encapsulated therapeutic agents such as drugs, genes, proteins, and metal ions specifically at their required site of action. Owing to physiological differences between malignant and normal cells, or between tumors and normal tissues, pH-sensitive nanosystems represent promising smart delivery vehicles for transport and delivery of anticancer agents. Furthermore, pH-sensitive systems... 

Magnetic micelle nanoparticles with thermoresponsive behavior were designed for thermo-triggered paclitaxel delivery. For this purpose, thermoresponsive triblock copolymer poly(N-isopropyl acrylamide)-b-polycaprolactone-b-poly(N-isopropyl acrylamide) was prepared. The magnetic micelle was formed by self-assembly of triblock copolymer on the magnetite which was coated by oleic acid. The size of the magnetic micelle was between 30–40 nm reported by transmission electron microscopy. Also, dynamic light scattering indicated the hydrodynamic diameter was thermal dependent. Moreover, the drug release profile showed thermo-triggered release of paclitaxel. Thus, the smart nanocarrier has potential... 

Magnetic micelle nanoparticles with thermoresponsive behavior were designed for thermo-triggered paclitaxel delivery. For this purpose, thermoresponsive triblock copolymer poly(N-isopropyl acrylamide)-b-polycaprolactone-b-poly(N-isopropyl acrylamide) was prepared. The magnetic micelle was formed by self-assembly of triblock copolymer on the magnetite which was coated by oleic acid. The size of the magnetic micelle was between 30–40 nm reported by transmission electron microscopy. Also, dynamic light scattering indicated the hydrodynamic diameter was thermal dependent. Moreover, the drug release profile showed thermo-triggered release of paclitaxel. Thus, the smart nanocarrier has potential... 

The bacterial strain MJ01 was isolated from stock tank water of one of the Iranian south oil field production facilities. The 16S rRNA gene of isolate, MJ01, showed 99% similarity to Bacillus subtilis. The results revealed that biosurfactant produced by this strain was lipopeptide-like surfactin based on FTIR analysis. Critical micelle concentration of produced surfactin in distilled water was 0.06 g/l. Wettability study showed that at zero salinity surfactin can change original oil-wet state to water-wet state, but in seawater salinity it cannot modify the wettability significantly. To utilize this biosurfactant in ex situ MEOR process, economical and reservoir engineering technical... 

Nowadays, as the oil reservoirs reaching their half-life, using enhanced oil recovery methods is more necessary and more common. Simulations are the synthetic process of real systems. In this study, simulation of water and surfactant injection into a porous media containing oil (two-phase) was performed using the computational fluid dynamics method on the image of a real micro-model. Also, the selected anionic surfactant is sodium dodecyl sulfate, which is more effective in sand reservoirs. The effect of using surfactant depends on its concentration. This dependence on concentration in using injection compounds is referred to as critical micelle concentration (CMC). In this study, an... 

New achievements in the realm of nanoscience and innovative techniques of nanomedicine have moved micro/nanoparticles (MNPs) to the point of becoming actually useful for practical applications in the near future. Various differences between the extracellular and intracellular environments of cancerous and normal cells and the particular characteristics of tumors such as physicochemical properties, neovasculature, elasticity, surface electrical charge, and pH have motivated the design and fabrication of inventive "smart" MNPs for stimulus-responsive controlled drug release. These novel MNPs can be tailored to be responsive to pH variations, redox potential, enzymatic activation, thermal... 

Solid phase extraction coupled with spectrophotometric detection was applied to trace amounts of Pantoprazole (PP) drug using Cetyltrimethylammonium bromide coated-iron oxide magnetite nanoparticles CTAB@Fe3O4 MNPs. After characterization of the prepared nano-adsorbents, experimental parameters affecting the extraction efficiency of the developed method were optimized. The results obtained showed that this proposed approach is applicable in concentrations ranging from 0.1 to 1.5 μg/ml (R2 = 0.9958) indicating that follows Beer's-Lambert law. The limit of detection and the limit of quantification calculated to be 0.014 and 0.04 μg/ml, respectively. The repeatability of the proposed method was... 

A soft template route is reported for the fabrication of polyaniline nanospheres via the oxidative polymerization of aniline in the presence of β-naphthalenesulfonic acid (β-NSA) as both surfactqant and dopant, and ammonium persulfate as oxidant at 2-5°C. Control over the morphology and size of the nanoparticles was achieved by changing the reaction medium via addition of an organic cosolvent (i.e. ethanol or ethylene glycol) and by controlling the concentrations of aniline and β-NSA and the molar ratio of β-NSA to aniline. By this means the size of the β-NSA-aniline micelles and the way that aniline monomer interacts with the micelles were controlled. In fact the lower dielectric constant... 

Targeted delivery by either passive or active targeting of therapeutics to the bone is an attractive treatment for various bone related diseases such as osteoporosis, osteosarcoma, multiple myeloma, and metastatic bone tumors. Engineering novel drug delivery carriers can increase therapeutic efficacy and minimize the risk of side effects. Developmnet of nanocarrier delivery systems is an interesting field of ongoing studies with opportunities to provide more effective therapies. In addition, preclinical nanomedicine research can open new opportunities for preclinical bone-targeted drug delivery; nevertheless, further research is needed to progress these therapies towards clinical... 

Nanotechnology could provide a new complementary approach to treat coronary artery disease (CAD) which is now one of the biggest killers in the Western world. The course of events, which leads to atherosclerosis and CAD, involves many biological factors and cellular disease processes which may be mitigated by therapeutic methods enhanced by nanotechnology. Nanoparticles can provide a variety of delivery systems for cargoes such as drugs and genes that can address many problems within the arteries. In order to improve the performance of current stents, nanotechnology provides different nanomaterial coatings, in addition to controlled-release nanocarriers, to prevent in-stent restenosis.... 

Porphyrins are organic compounds that continue to attract much theoretical interest, and have been called the “pigments of life”. They have a wide role in photodynamic and sonodynamic therapy, along with uses in magnetic resonance, fluorescence and photoacoustic imaging. There is a vast range of porphyrins that have been isolated or designed, but few of them have real clinical applications. Due to the hydrophobic properties of porphyrins, and their tendency to aggregate by stacking of the planar molecules they are difficult to work with in aqueous media. Therefore encapsulating them in nanoparticles (NPs) or attachment to various delivery vehicles have been used to improve delivery... 

Hydrogels with remarkable hydrophilicity and tunable toughness are appealing materials to serve as superabsorbent polymers. However, chemically cross-linked hydrogels often suffer from low toughness regardless of their considerable swelling, restricting their widespread applications. In comparison, the network of physically cross-linked hydrogels can be regulated to meet both a high swelling ratio and considerable toughness. Here, we develop superabsorbent and tough hydrophobic associated hydrogels using terpolymerization of poly acrylic acid (PAA), polyacrylamide (PAM), and lauryl methacrylate (LMA) within the micelles formed by sodium dodecyl sulfate (SDS) surfactant. To this end, various...