Sharif Digital Repository

Gold nanorods (GNRs) can be used in various biomedical applications; however, very little is known about their in vivo tissue distribution by radiolabeling. Here, we have developed a rapid and simple method with high yield and without disturbing their optical properties for radiolabeling of gold rods with iodine-131 in order to track in vivo tissue uptake of GNRs after systemic administration by biodistribution analysis and γ-imaging. Following intravenous injection into rat, PEGylated GNRs have much longer blood circulation times. We have developed a rapid and simple method for radiolabeling of gold rods with iodine-131 in order to track in vivo tissue uptake of gold nanorods after systemic... 

An aqueous two-phase system (ATPS) containing polyethylene glycol (PEG) and potassium phosphate (K2HPO4) was used for partitioning and partial purification of alkaline protease produced by Bacillus licheniformis ATCC 21424. The effect of PEG molar mass, pH and concentration of NaCl salt addition on partition coefficient, yield and purification factor (PF) for ATPS were studied. The highest partition coefficient (5.3) was achieved in an ATPS of 25% (w/w) PEG 10,000 (g/mol) and 10% (w/w) NaCl at pH 9. Cation and anion exchange chromatography was employed for purification of alkaline protease from protein mixture and the yield and PF for enzyme fractions were obtained to make a comparison... 

Due to the hopeful potential of nanoparticles in medicine, they have attracted much attention for various applications such as targeted drug/gene delivery, separation or imaging. Interaction of NPs with the biological environment can lead to a wide range of cellular responses. In order to have safe NPs for biomedical applications, the current biocompatibility researches are particularly focused on the severe toxic mechanisms which cause cells death. These mechanisms are apoptosis, autophagy and necrosis, which can also be intricately linked with the cell-life cycle, as there are various check-points and controls in a cell's life cycle to ensure appropriate division processes. Mechanisms by... 

Reduced graphene oxide nanoribbons functionalized by amphiphilic polyethylene glycol (rGONR-PEG) were applied to attach arginine-glycine-aspartic acid (RGD)-based peptide and cyanine dye 3 (cy3) for targeting ανβ3 integrin receptors on human glioblastoma cell line U87MG and its selective fluorescence imaging, respectively. The rGONR-PEG suspension with a concentration of 100 μg mL -1 showed ∼14 and 2.4-fold higher near infrared (NIR) absorption at 808 nm than GONR (with dimensions of ∼80 nm × 1 μm) and rGO-PEG sheets (with lateral dimensions of ∼2 μm), respectively. The rGONR-PEG-cy3-RGD exhibited highly efficient NIR photothermal therapy performance (concentrations ≥1.0 μg mL-1 resulted in... 

The objective of this study was to investigate the effects of two compatibilizers, namely maleated polypropylene (PP-g-MA) and maleic anhydride grafted poly (ethylene-co-octene) (EOC-g-MA), on the morphology and thus properties of ternary nanocomposites of polypropylene (PP)/ethylene-octene copolymer (EOC)/clay nanocomposite. In this regard the nanocomposites and their neat polymer blend counterparts were processed twice using a twin screw extruder. X-ray diffraction, transmission electron microscopy, Energy dispersive X-ray spectroscopy, and scanning electron microscopy were utilized to characterize nanostructure and microstructure besides mechanical and rheological behaviors of the... 

A method based on solid-phase microextraction (SPME) followed by on-fiber derivatization and gas chromatography-mass spectrometry detection (GC-MS) for determination of phenol in air was developed. Three different types of SPME fibers, polar and non-polar poly(dimethylsiloxane) (PDMS) and polyethylene glycol (PEG) were synthesized using sol-gel technology and their feasibility to the sampling of phenol were investigated. Different derivatization reagents for post on-fiber derivatization of phenol were studied. Important parameters influencing the extraction and derivatization process such as type of fiber coating, type and volume of derivatizing reagent, derivatization time and temperature,... 

Thermal degradation behavior of multi-wall carbon nanotubes (MWCNTs)/ultra high molecular weight polyethylene (UHMWPE) nanocomposites, with different nanotubes contents (0.5, 1.5 and 3.5 wt%) prepared via in-situ polymerization technique have been investigated using thermal gravimetric analysis (TGA). TGA spectra revealed that these nanocomposites had enhanced thermal stability and no significant mass loss (<0.4 wt%) occurred up to 350°C. Thermal degradation of these UHMWPE/MWCNT nanocomposites was investigated in terms of parameters such as the onset temperature of degradation (T 10), the decomposition temperature at 50% wt loss (T 50), the degradation temperature of maximum rate of the... 

The radical chlorination of polyethylene was carried out in perchloroethylene solvent using chlorine gas and ultraviolet photoradiation to investigate a reaction kinetics model. The recurrent structure of chloromethylene (-CHCl-) and methylene (-CH 2 -) groups and the percentage of substituted chlorine were determined using hydrogen-nuclear magnetic resonance (H-NMR) (500 MHz) spectra. A kinetics model has been proposed for this reaction in which the conversion of methylene (-CH 2 -) units to chloromethylene (-CHCl-) units was considered to be the main reaction step. The simplified version of the obtained kinetics model indicates that the reaction is first order with respect to the chlorine... 

Superparamganetic iron oxide-based contrast agents in magnetic resonance imaging (MRI) have offered new possibility for early detection of lymph nodes and their metastases. According to important role of nanoparticle size in biodistribution, magnetite nanoparticles coated with different polyethylene glycol (PEG) concentrations up to 10/1 PEG/iron oxide weight ratio in an ex situ manner. To predict the PEG-coated nanoparticle behavior in biological media, such as blood stream or tissue, colloidal stability evaluation was performed to estimate the coating endurance in different conditions. Accordingly, optical absorbance measurements were conducted in solutions with different values of pH and... 

In this research, ultrahigh-molecular-weight polyethylene (UHMWPE)/multiwalled carbon nanotube (MWCNT) nanocomposites with different nanotube concentrations (0.5, 1.5, 2.5, and 3.5 wt %) were prepared via in situ polymerization with a novel, bisupported Ziegler-Natta catalytic system. Magnesium ethoxide [Mg(OEt) 2] and surface-functionalized MWCNTs were used as the support of the catalyst. Titanium tetrachloride (TiCl 4) accompanied by triethylaluminum constituted the Ziegler-Natta catalytic system. Preparation of the catalyst and the polymerization were carried out in the slurry phase under an argon atmosphere. Support of the catalyst on the MWCNTs was investigated with Fourier transform... 

A single-step green method for effective reduction and functionalization of graphene oxide (GO) by glucose was developed. Then, efficacy of the glucose-reduced GO sheets in photothermal therapy of LNCaP prostate cancer cells was investigated in vitro. The GO suspension reduced and functionalized by glucose in the presence of Fe catalyst showed a biocompatible property with an excellent near-infrared (NIR) photothermal therapy efficiency better than hydrazine-reduced GO, single-wall and multi-wall carbon nanotube suspensions which even showed some levels of toxicities. For complete destruction of the cancer cells at some time intervals of NIR irradiation (e.g., 0.5 and 12 min with a power... 

The feasibility of fabricating relatively monodispersed polymeric nanoparticles by the electrospray method in a modified electrospray set-up is demonstrated in this study. The polymer solution is electrosprayed in the single cone-jet regime through a nozzle. After solvent evaporation, during which particles pave from the nozzle to collector, the fabricated nanoparticles can be collected in deionized water, which plays the role of surfactant for particles, not allowing them to aggregate. The results of scanning electron microscope and dynamic light scattering analysis clearly confirm the fabrication of monodispersed spherical polymeric nanoparticles with diameter range from 80 to 120nm with... 

UHMWPE composite materials are increasingly used in armors design due to their high strength-to-weight ratios and energy absorption capacities. In this study the effect of production parameters upon the terminal ballistic properties of UHMWPE composite were examined under different conditionings. The composite armor plate laminates were produced by hot pressing with three different pressing times from 10-30 minutes and the laminates conditioned at +115, +125, and +135°C. The molding temperature of SK66 fiber composite has the main direct effect on the ballistic absorption energy, so the relation of molding temperature with the adhesive bonding force between layers, the thickness of the... 

Strategic health, safety, and environmental management system (HSE-MS) involves systematic and cooperative planning in each phase of the lifecycle of a project to ensure that interaction among the industry group, client, contractor, stakeholder, and host community exists with the highest level of health, safety, and environmental standard performances. Therefore, it seems necessary to assess the HSE-MS performance of contractor(s) by a comparative strategic management model with the aim of continuous improvement. The present Strategic Management Model (SMM) has been illustrated by a case study and the results show that the model is a suitable management tool for decision making in a contract... 

Catalytic activity of carbon/Pt nanoparticles modified TiO 2 nanotubes electrode was studied by using dopamine contained solutions. The TiO 2 nanotubes electrode was prepared using anodizing method in aqueous solution. The electrochemical pulse method was then applied for electrodeposition of Pt nanoparticles onto the TiO 2 nanotubes. Further modification was achieved by decomposition of polyethylene glycol in a tube furnace to have a carbon/Pt nanoparticles modified TiO 2 nanotubes electrode. The final modified electrode could successfully detect the electro-oxidation of dopamine in a ImM contained solution using cyclic voltametry method. Also, a high sensitivity towards the oxidation of... 

The influence of electron beam (EB) irradiation and organoclay (OC) loading on the properties of low-density polyethylene (LDPE)/ethylene-vinyl acetate (EVA) blends was investigated. The samples were subjected to the EB irradiation with the dose values of 50 and 250kGy. X-ray diffraction (XRD), gel content, mechanical, thermal, and electrical properties were utilized to analyze the characteristics of the LDPE/EVA blends with and without OC at different irradiation dosages. Gel content analysis showed that the OC promotes considerably the insoluble part so that the LDPE/EVA blends filled with OC become fully crosslinked at 250kGy; possibly through the formation of further crosslinks between... 

Polyrotaxanes consisting of cyclodextrin rings, polyethylene glycol axes and quantum dot (QD) stoppers were synthesized and characterized. The molecular self-assembly of polyrotaxanes led to spindlelike nano-objects whose shape, size and position were dominated by QD stoppers. Due to their well-defined molecular self-assemblies, carbohydrate backbone, high functionality and several types of functional groups together with the high luminescence yield, synthesized hybrid nanostructures were recognized as promising candidates for biomedical applications. The potential applications of the molecular self-assemblies as drug-delivery systems was investigated by conjugation of doxorubicin (DOX) to... 

A new technique for preparation of an unbreakable solid-phase microextraction (SPME) fiber, using sol-gel technology is developed. Primarily, an ultrathin two-dimensional intermediate film was prepared by hydrolysis of 3-(trimethoxysilyl)-1-propanthiol self-assembled monolayer grafted onto gold, then a stationary phase by electrodeposition of 3-(trimethoxysilyl) propylmethacrylate as a precursor, tetramethyl orthosilicate and polyethylene glycol as a coating polymer was produced. The scanning electron microscopy images revealed that the new fiber exhibits a rather porous and homogenous surface. The thermal stability of the fabricated fiber was investigated by thermogravimetric analysis. The... 

WO3 thin films were fabricated by sol-gel method using polyethylene glycol (PEG) as dispersing agent. Physical and photoelectrochemical properties of the synthesized nanocrystalline films were studied by varying weight ratio of PEG to tungsten precursor (x). Based on AFM observations and statistical modeling of the WO3 surface, the thickness of the films increased by increasing the amount of x with a nearly linear fashion while the surface roughness reached to a saturated value. However, the film synthesized with x = 4 showed a chaotic surface behavior. Optical analysis revealed that by increasing the x, transmittance of the films decreased while their band gap energies remained unchanged.... 

Iron oxide nanoparticles, γ-Fe2O3NP, were deposited onto the surface of multi-walled carbon nanotubes and CNT/γ-Fe2O3NP hybrid nanomaterials were obtained. Then linear-dendritic ABA type block copolymers consisting of polyethylene glycol as B block and poly(citric acid) as A block, PCA-PEG-PCA, were synthesized and cisplatin (cis-diamminedichloroplatinum (CDDP) - a platinum-based chemotherapy drug) was conjugated with their carboxyl functional groups and CDDP/PCA-PEG-PCA anticancer prodrugs were prepared. Noncovalent interactions between CDDP/PCA-PEG-PCA anticancer prodrugs and CNT/γ-Fe2O3NP hybrid nanomaterials led to CDDP/PCA-PEG-PCA/CNT/γ-Fe2O3NP drug delivery systems. There are several...