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Volume 4, Issue 3 (12-2015)
Abstract
In order to improve the properties of myofibrillar protein-based film from silver carp (Hypophthalmichthys molitrix), nanofibrillated cellulose (NFC) at 3 levels (1, 3 and 5%) was used. Optimum treatment was determined by evaluating the mechanical, physical and optical properties as well as scanning electron microscopy analysis (SEM). Cellulose nanoparticles had no effect on tensile strength but reduced the elasticity of film (p≤0.05). Water vapor barrier property (WVP) and other physical properties of the films were improved by addition of nanofibrillated cellulose at 1%, but decreased at higher concentrations (p≤0.05. Based on SEM, low concentrations of nanoparticles showed more homogeneous dispersion and films had a smoother and better cross-sectional area compared to the higher levels of nanoparticles. Generally, low levels of nanoparticles could be effective to improve the mechanical and physical properties of myofibrillar protein - nanofibrillated cellulose films.
Volume 4, Issue 3 (12-2020)
Abstract
Metformin enhances insulin's effect and increases cells’ sensitivity to insulin. In this paper, nanocomposite was designed and used in the metformin release system, which was able to release the required drug in a controlled manner. In this research, nanoparticles of zinc oxide (ZnO) were prepared via the sol-gel method. The experimental design central composite response surface method was applied for the optimization of the nanoparticles based on varied variables such as the weight of zinc acetate (gr) (X 1) and the volume of triethanolamine (ml) (X2). The particle size of the optimized nanoparticle was reported to be 28 ± 21.27 nm; zeta potential and PdI were 25.54 ± 1.64 mV, 0.168 ± 0.05 respectively. The chitosan polymer was used to improve environmental compatibility and increase drug release control; finally, metformin was loaded on the optimized nanocomposite. Structural properties were analyzed using scanning electron microscopy (SEM) X-Ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and Dynamic Light Scattering (DLS). The SEM images showed that the average nanocomposite size was 40 nm. The results of XRD patterns and SEM images were also consistent with each other and the average particle size was the same. Infrared spectrophotometry showed the presence of chitosan used to coat nanoparticles on their surfaces and confirmed the loading of metformin. An in-vitro metformin release from the nanocomposite was conducted in PBS (pH=7.4) and analyzed by a spectrophotometer at 233 nm. Metformin has a high solubility in water, and since it is difficult to prepare a slow release form of high-solubility drugs, the aim of this study was to design a slow-release formulation of metformin with a suitable profile that could control release without explosive release for up to 120 hours.
Volume 4, Issue 4 (9-2018)
Abstract
Aims: Uropathogenic Escherichia coli (UPEC) is one of the most important causative agents of urinary tract infection (UTI). UPEC isolates persist in the body through biofilm formation. The successful adhesion is the most important step of biofilm formation. Type 1 and P are bacterial surface appendices, which play a pivotal role in of UPEC. The aim of this study was to assess the effect of on the initial adhesion gene expression in UPEC isolates.
Materials & Methods: The presence of and genes among 60 UPEC isolates was investigated by PCR; 5 potent producer UPEC strains from patients with UTI were exposed to the sub-minimum inhibitory concentration of Expression of the and genes was evaluated by real-time PCR.
Findings: Of the 60 UPEC isolates, biofilm formation was seen in 27 (45%) of isolates, 5 of which produced strong The result of PCR assay showed that was seen in 57 (95%) of the 60 UPEC isolates and was seen in 58 (96.6%) of isolates, respectively.and expression 7 and 8 fold in all 5 isolates, respectively.
Conclusion: Sub-MIC concentrations of remarkably decreased the expression the and genes in strong forming UPEC strains, but cannot prevent biofilm formation.
Materials & Methods: The presence of and genes among 60 UPEC isolates was investigated by PCR; 5 potent producer UPEC strains from patients with UTI were exposed to the sub-minimum inhibitory concentration of Expression of the and genes was evaluated by real-time PCR.
Findings: Of the 60 UPEC isolates, biofilm formation was seen in 27 (45%) of isolates, 5 of which produced strong The result of PCR assay showed that was seen in 57 (95%) of the 60 UPEC isolates and was seen in 58 (96.6%) of isolates, respectively.
Conclusion: Sub-MIC concentrations of remarkably decreased the expression the and genes in strong forming UPEC strains, but cannot prevent biofilm formation.
Volume 4, Issue 4 (3-2021)
Abstract
Research subject: Polymer nanofibers have attracted much industrial interest over the past decade. In general, these fibers are suitable for a variety of applications including medical applications, insulation, capacitors, advanced aerospace technologies, and so on. Specifically in aerospace technology, the used materials must be thermally stable with suitable electrical conductivity. However, many of these polymer nanofibers suffer from low temperature degradation and low electrical conductivity, limiting their use in many potential applications. Graphite has unique properties such as high conductivity and high thermal stability. This exceptional material can be included as a nanoparticle in polymer nanofibers to modify electrical and thermal properties.The aim of this research was to investigate the effect of addition of graphite nanoparticle on thermal and electrical propertiesof polymer fibers.
Research approach: For this purpose, polyvinyl alcohol 72000 (PVA) as a non-conductive polymer and graphite nanoparticles were used. Polyvinyl alcohol-graphite nanofibers were synthesized method by electrospinning technique under optimized parameters. The optimum conditions for the electrospinning process were: PVA concentration of 8%, applied voltage of 22 Kv, flow rate of 10 ml and tip/collector distance of 20 cm.
Main results: Scanning electron microscopy (SEM) studies showed that produced PVA fibers were smooth, continuous without any bead, with a diameter of about 350 nm. The PVA / graphite nanofibers were also smooth but much thinner (about 200 nm) than PVA fibers at the same processing parameters. Moreover, X-ray patterns of PVA/graphite nanofibers include peaks of graphite particles in the structure and slso the suppression of crystallinity. According to the results of 4 point probe teste, by increasing weight percentage of graphite in the fibers, electrical conductivity increased up to 0.5
. The thermal behavior of PVA nanofibers after mixing with graphite was also investigated by differential calorimetry analysis (DSC) and TGA. It was demonstrated that PVA / graphite nanofibers are thermally stable up to 300 ° C.Volume 4, Issue 4 (3-2021)
Abstract
Research subject: In recent years, due to limited water resources and the extraordinary increase in nitrates in the environment, efforts to remove and control in order to benefit from the natural adsorbents have been made. Although according to the negatively charged surface of bentonite particles, absorbent needs improvement.
Research approach: In the current study, the adsorption of nitrate columns by the modified calcium montmorillonite adsorbent was investigated. Furthermore, In order to change the surface load and increase the adsorption efficiency, three-step acid leaching, oxidation layering, and loading of the cationic surfactant hexadecyltrimethylammonium bromide on the adsorbent were performed. Molecular interaction and crystallography of pure montmorillonite and synthetic nano-adsorbent (ACZ) were characterized by Fourier transform infrared spectroscopy and X-ray analysis. Moreover, the morphology of ACZ nano adsorbents was evaluated using Transmission electron microscopy and scanning electron microscopy.
Main results: Nanoparticle compaction and less access to pores and cavities in the fixed bed column reduced the adsorbent capacity inside the column compared to the discontinuous system.
The results showed that an increase in inlet concentration from 80 to 150 mg/L increased the adsorption capacity from 67.39 to 88.25 mg/g. Reducing the inlet flow rate increased the penetration time, interaction, and greater access to the binding sites for nitrate ions and finally improved the column performance and increased the inlet flow rate reduced the adsorption capacity and breakthrough time. Therefore, the adsorption of nitrate ions by the stage of internal mass transfer is controlled and depends on the duration of interaction and the possibility of penetration into the active sites. With increasing the bed height from 4.2 to 9 cm, there was a significant increase in adsorption capacity from 60.608 to 77.167 mg/g. The effect of detergents and recovery showed an absorption column; After 3 leaching steps, acid leaching played an important role in increasing column recovery. Experimental data with correlation coefficients of R2>0.95 corresponded to Thomas and Yoon-Nelson kinetic models.
In this study, the ACZ nano adsorbent column for rapid removal of nitrate ions from aqueous solutions was introduced and for use in reusable systems was proposed.
Volume 5, Issue 1 (6-2016)
Abstract
Silver nanoparticles (AgNPs) are widely used in consumer products mainly due to their antimicrobial action. The rapid increase in the use of nanoparticles has driven more attention to their possible ecotoxicological effects. In this study: first, acute effects of colloidal AgNPs during embryonic stage of Persian sturgeon and Starry sturgeon were investigated and then in Starry sturgeon, their short-term effects during early life stages (before active feeding commences) were analyzed. Based on the obtained results from the acute toxicity tests, AgNPs induced a dose-dependent toxicity in both species during early life stages. The short-term toxicity test was performed using 0, 0.025, 0.05 and 0.1 mg/l of colloidal AgNPs. Silver accumulation in larvae exposed to 0.1 mg/l AgNPs was recorded significantly higher than the control treatment (P<0.05). However, the obtained survival rate data did not indicate any significant differences among treatments.
Volume 5, Issue 1 (7-2021)
Abstract
Plant fibrous suspensions require electrostatically cationic polymers to provide proper and strong structures during papermaking. The charge bearing naturally and synthetically polymers (Polyelectrolytes), are considered as the most chemicals used in cellulosic products mills, due to improvement in the fibrous suspension and network properties. For this, cationic acrylamide polymer (CPAM) and anionic nano cellulose (ANC) were added individually and in combination forms into the fibrous suspension recycled from brown packaging papers. Compared to the blank sample without any the polymeric additive, the polymeric contained suspensions and networks revealed improvements in fibrous suspension properties; i.e., retention, freeness and the solid materials loss during the network formation; and in the fibrous dried network, include density, tensile and burst strengths. Individually application of each CPAM and ANC increased the suspension retention (productivity) as 8% and 2%, resp. Fibrous suspension freeness and loss materials content continuously increased and decreased up to 47%, respectively that could provide significant technologically and economically benefits. Paper density (+5%), tensile (+17%) and burst (+27%) properties improved drastically compared to the blank. But, tear strength of fibrous network decreased (-4%) which could be attributed to the network higher fines contents and retention, originated from the acrylamide polyelectrolyte flocculation effect. Individually application of ANC also enhanced suspension retention, network density, tensile and burst strengths and declined network tear strength with lesser suspension freeness and loss. Anionic nature, high specific surface area and huge hydrogen bonding potential of ANC are the main reasons of the obtained results. ANC post addition to CPAM contained suspension resulted in tear reduction, but higher suspension retention and freeness, together with higher density, tensile and burst strength of cellulosic network.
Volume 5, Issue 1 (7-2021)
Abstract
Research subject: Nanomaterials are substances that, because of their size, can easily penetrate small pores and apply their impact. Nanofluids can allow appropriate wettability change in the reservoir rock, therefore, an accurate understanding of the behavioral mechanisms of these nanofluids is important in changing the wettability. This is because if there is no proper understanding of these mechanisms, they may exhibit the opposite behavior and cause damage to the reservoir. In previous research, CuO / TiO2 / PAM nanocomposite was synthesized and mechanistically introduced.
Research approach: In this study, in continuation of the previous study, the behavioral and mechanism study has been investigated in a more accurate and documented manner, and spectral absorption tests, chemical flooding, and relative permeability diagrams confirm the effectiveness of enhanced oil recovery results of this nanocomposite. In carbonate rocks due to the positive surface charge of the rock and the negative charge of the nanocomposite, adsorption of nanomaterials in a double electrode layer state has been suggested as the dominant mechanism of wettability change. In sandstone rocks due to the charge coincidence of rock surface and nanomaterials which are both negative, the mechanism of disjoining pressure was the dominant mechanism of wettability change. To prove the abovementioned behaviors 200 ppm concentration of nanofluid was analyzed by spectroscopy method of adsorption analysis to validate the attraction forces of the nanocomposite with carbonate rocks and repulsion forces with sandstones.
Main results: Dynamic chemical flood tests were performed to confirm the effectiveness of this material in increasing oil production and showed 8.5% and 6.35% increase in oil production for carbonate and sandstone lithologies, respectively. Relative permeability diagrams showed an intersection point in the carbonate system with a 10% increase in water saturation and an intersection point in the sandstone system with a 12% increase in water saturation and the behavioral effect of the material at the studied concentrations.
Volume 5, Issue 1 (7-2021)
Abstract
Research subject:Well-designed plastic foams, with respect to their cell density and cell size, open-or-close cells, and the cell uniformity, compared to their counterpart unfoamed plastic parts, beside of having the advantages of less material consumption, dimensional stability, better processability, and a higher surface quality, they can have superior mechanical and physical properties, including strength to weight, impact strength, thermal and dielectric properties. The temperature distribution in the different zones of the extruder, the qualities and quantities of the nanoparticle additives and their dispersion in the polymer matrix can have significant effect on the mechanical properties of the produced foams by the extruder.
Research approach: In this study, using an extruder, MA-g-polypropylene microcellular foams, containing 3, 7 and 9 wt% of nano-clay particles, were produced under three temperature arrangements on the extruder and the material and the processing effects on the mechanical properties were investigated.
Main results: The result of this investigation shows that adding of nanoclay improves the mechanical properties of MA-g-PP.s foams. As an example, the results show that the sample with 7 wt% of surface modified nanoclay, owns about 10% higher impact toughness compared to the samples produced without nanoclay. Also for the same samples a rise of about 5% was recorded in Young's modulus. The microstructural studies of the produced foams by scanning electron microscope (SEM) show that adding of nanoclay can result on more foam uniformity and smaller cell size. In this study, the smallest average cell size (87.5 μm) and the lowest density (0.3 g/cm3) were recorded for a sample with 7wt% nanoclay.
Volume 5, Issue 1 (7-2021)
Abstract
Abstract
Research Subject: Breast cancer is one of the most common cancer in the world with the highest mortality rate in women. Chemotherapy is the typical therapy for the cancer. However, it has side effects due to damage to healthy cells. Targeted drug delivery by nano carriers to the cancerous cells reduces the toxic side effects on normal cells. Serum albumin is a widely used drug carrier because of its availability, ease of preparation, and binding ability to various ligands. Attachment of iron oxide nanoparticles to albumin can control their distribution by applying an external magnetic field.
Research Approach: In this study, albumin nanoparticles attached to superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized and loaded with 5-Fluorouracil (5-FU) anticancer drug by using the desolvation technique. The produced nanoparticles were characterized in terms of size, surface charge, and drug entrapment, by dynamic light scattering (DLS) and UV-Vis spectrophotometry. The cytotoxic effects of 5FU-loaded magnetic albumin nanoparticles and free 5FU on MCF7 cells were evaluated with the MTT assay. The internalization of nanoparticles in MCF-7 cells was confirmed by Prussian blue staining. In the end, the effects of nanoparticles on cell cycle and apoptosis were evaluated by flow cytometry using propidium iodide.
Main Results: The mean particle size and zeta potential of 5FU loaded albumin nanoparticles and albumin magnetic nanoparticles were 220 nm, -25.8 mV, and 221 nm, -28 mV respectively. Drug entrapment efficiency and drug loading efficiency were also, 20%, 1%, and 15.8%, and 0.06% for albumin nanoparticles and magnetic albumin nanoparticles in turn. The drug-loaded magnetic albumin nanoparticles showed higher cytotoxicity than the free drug on MCF-7 cells. The flow cytometry cell cycle analysis showed more cytotoxicity of albumin nanoparticles in comparison with other groups. According to these results, it can be said that 5-FU loaded magnetic albumin nanoparticles were more effective and deserve further studies in the cancer treatment.
Keywords: Albumin magnetic nanoparticles, 5-fluorouracil, targeted drug delivery, MCF-7 cell line
Volume 5, Issue 2 (9-2021)
Abstract
The rise of bacterial infections has become a serious problem in human societies. As a result, the development of nanocomposite materials based on biocompatible and non-hazardous materials, besides having antimicrobial and biocompatibility or non-cytotoxicity, associated with unique structural properties, possesses a great importance. Research approach: In this study, bacterial cellulose (BC)/polypyrrole (PPy) and zinc nanoparticles (ZnO), which simultaneously have antimicrobial properties and cell proliferation, were introduced as a new generation of nanocomposite scaffolds produced by freeze-drying. To begin with, ZnO with different weight percentages of 1%, 3% and 5% was added to BC and then PPy in the amount of 2 mmol was embedded in the structure by in situ polymerization. FESEM images proved that the nanofibrous and porous structure of BC was also preserved in the presence of PPy and ZnO. However, after adding PPy and ZnO, they formed a dense structure and microstructure of grape clusters. By adding 2 mmol PPy into BC and upon in situ synthesizing, the tensile strength and Young modulus of BC were significantly reduced to 71 MPa and 2.5 GPa, respectively. On the other hand, with the addition of ZnO nanoparticles, the mechanical properties significantly increased (both of Young modulus and tensile strength compared to BC/PPy samples) due to the compaction of the nanocomposite aerogel’s structure and the formation of the interface of ZnO nanoparticles with both polymers of BC and PPy. The observation of the inhibition zone in the culture medium containing two gram-positive and negative bacteria, well proved the antibacterial ability of ternary nanocomposite scaffolds. The results of MT9 related to L929 on aerogels showed that by adding 3% of ZnO nanoparticles, adhesion and cell proliferation increased significantly during different days of 1 day, 5 days and 7 days of culture.
Volume 5, Issue 3 (12-2021)
Abstract
Research subject: Biodegradable compounds with high mechanical and thermal properties are one of the intersting research topics. Polylactic acid is an aliphatic polyester with high biodegradability and flexibility. It, however, suffers from several weaknesses such as high permeability to water vapor and gases, low glass transition temperature, poor thermal stability and brittleness which can be improved by the incorporation of nano-scale fillers giving rise to bionanocomposites. The aim of this study was to investigate the effect of the simultaneous incorporation of cellulose nanocrystals and nanosilver on the mechanical, thermal and water vapor permeability behavior of polylactic acid-based films.
Research approach: Polylactic acid films and their bionanocomposites containing different levels of cellulose nanocrystals (0.01, 0.03 and 0.05 g) and nanosilver (0.01 g) were prepared by solution casting method. To improve compatibility and miscibility of the polymer, cellulose nanocrystals were reacted with acetic anhydride and modified. FTIR spectroscopy, tensile test, thermal properties (DSC), migration test and antibacterial properties were used to study the properties of the samples. The water vapor permeability of the samples were also measured.
Main results: The addition of cellulose nanocrystals, increased the glass transition temperature (Tg) and melting point (Tm) of the samples. The presence of cellulose nanocrystals increased the tensile strength and modulus of elasticity of the bionanocomposite relative to pure polylactic acid. With the addition of cellulose nanocrystals, permeability was reduced by about 25%. As the amount of cellulose nanocrystals increased, the swelling and water absorption of the samples increased significantly. The migration rate of the samples also decreased after the addition of nanocellulose.
Research approach: Polylactic acid films and their bionanocomposites containing different levels of cellulose nanocrystals (0.01, 0.03 and 0.05 g) and nanosilver (0.01 g) were prepared by solution casting method. To improve compatibility and miscibility of the polymer, cellulose nanocrystals were reacted with acetic anhydride and modified. FTIR spectroscopy, tensile test, thermal properties (DSC), migration test and antibacterial properties were used to study the properties of the samples. The water vapor permeability of the samples were also measured.
Main results: The addition of cellulose nanocrystals, increased the glass transition temperature (Tg) and melting point (Tm) of the samples. The presence of cellulose nanocrystals increased the tensile strength and modulus of elasticity of the bionanocomposite relative to pure polylactic acid. With the addition of cellulose nanocrystals, permeability was reduced by about 25%. As the amount of cellulose nanocrystals increased, the swelling and water absorption of the samples increased significantly. The migration rate of the samples also decreased after the addition of nanocellulose.
Volume 5, Issue 3 (12-2021)
Abstract
Research subject: Solar cells has gained a great attention as a green, renewable and cheap energy resources. To overcome the challenging technical problems and improve their competitiveness with silicone solar cells, the design, synthesis and development of new materials with engineered band gap energies has found an undeniable importance.
Research approach: Herein, the synthesis of a polymer with donor-acceptor structure based on polyaniline grafted to ZnO nanoparticles at one end and naphthalene moiety at the other end of chains, and investigation of their chemical structure, composition, morphology, optical and electrochemical properties is reported. The chemical structure of the materials were analyzed by FT-IR and 1H NMR spectroscopy. The organic and inorganic contents of materials were determined by thermal gravimetric analysis (TGA) and atomic absorption spectroscopy (AAS) techniques. The morphology and size of nanoparticles were observed by scanning electron microscopy (SEM). The optical and electrical band gap energy of the samples were measured by ultraviolet visible-diffuse reflectance (UV-Vis-DRS) spectroscopy and cyclic voltammetry (CV) diagrams.
Main results: The chemical structure of designed materials has been successfully confirmed by the results of FT-IR and 1H NMR spectra. TGA and AAS analysis have indicated that the synthesized final material has contained about 10% of ZnO and 90% of organic parts including toluene-2,4-diisocyanate, 2,4-diaminotoluene, polyaniline and naphthalene groups. An almost highly uniform spherical nanoparticles with sizes about 70 nm has been observed by SEM images. UV-Vis-DRS spectroscopy and CV diagrams have revealed that by grafting ZnO nanoparticles and naphthalene moiety to the polyaniline chain ends, the optical and electrical band gap energy of the sample were lowered to 1.19 and 0.95 eV, respectively. It was concluded that the grafted groups to chain ends has increased the length of conjugated system, lowering the energy level of lowest unoccupied molecular orbital (LUMO) and increasing the energy level of highest occupied molecular orbital (HOMO). Detailed analysis of CV diagrams has indicated that the effect in lowering of LUMO has been a bit more pronounced than the increasing of HOMO energy level.
Volume 5, Issue 3 (12-2021)
Abstract
Research subject: In this study, EDTA-functionalized Fe3O4@SiO2 magnetic nanocomposites with core-shell structure were synthesized to remove divalent cadmium ions from aqueous solutions.
Research approach: During the first step, Fe3O4@SiO2 nanosphere core-shell is synthesized using nano Fe3O4 as the core, TEOS as the silica source and PVA as the surfactant. This strategy relies on the covalently bonding of ethylendiaminetetraacetic acid to bis(3-aminopropyl)amine and cyanuric chloride functionalized magnetic nanoparticles. In the next step, characteristics of surface functional groups, crystal structure, magnetic properties, size and surface morphology of these nanoparticles were investigated, identified and analyzed using physico-chemical characterization techniques including fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), vibration sample magnetometry (VSM) and Brunauer-Emmett-Teller (BET) surface area analyzer. The adsorbent, due to its magnetic property, could be simply separated from the reaction mixture by a permanent magnet and reused in five consecutive cycles without considerable loss in its activity.
Main results: To probe the nature of the adsorbent, various experiments were investigated like adsorbent dose and contact time were optimized. Kinetic studies and the effect of different amounts of adsorbent to remove divalent cadmium ions from aqueous solutions show a maximum adsorption of 94% at ambient temperature. Moreover, the recyclability of Fe3O4@SiO2-EDTA was investigated in order to remove the divalent cation for successive adsorption-desorption cycles. All the results of studies show that the synthetic nanocomposite Fe3O4@SiO2-EDTA is an effective, recyclable adsorbent with excellent performance for the removal of divalent cadmium.
Volume 5, Issue 3 (12-2021)
Abstract
Research subject: The use of hydroxyapatite nanoparticles (HAp) in traditional polymers as reinforcing agent has been reported. While there are a limited number of reports regarding the effect of HAp morphology on the mechanical properties of the polymeric matrix, no research on this effect on supermolecular polymers has been reported so far. This study investigates the hypothesis that incorporation of unidirectionally grown HAp nanoparticles (rod-like nanoparticles, rHAp) into supramolecular polycaprolactone (SPCL) leads to the synthesis of a new bioactive construct.
Research approach: For this, rHAp nanoparticles were first synthesized by microemulsion method and then functionalized with 2-ureido-4[1H]-pyrimidinone (UPy) groups. Moreover, PCL was functionalized and converted to supramolecular structures by reacting the hydroxyl terminal groups with UPy groups. Finally, SPCL/rHAp nanocomposites were synthesized by solution casting method and their structure and properties were examined using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), universal testing machine and simulated body fluid (SBF).
Main results: According to the results, microemulsion is an efficient procedure for the synthesis of rod-like nanoparticles with high phase purity. On the other hand, based on the results, it is possible to functionalize these nanoparticles with UPy. Tensile test showed that by incorporation of these modified nanoparticles into SPCL, a significant increase in both elastic modulus and tensile strength can be observed. In fact, while the initial PCL was a waxy solid, modification with UPy and then incorporation of modified nanoparticles made it an elastic material. Finally, the obtained results indicated high bioactivity of supramolecular nanocomposites compared to the sample without filler. Therefore, supramolecular SPCL/rHAp nanocomposites with bioactive properties and dynamic character can be used as a suitable replacement for bone tissue defects.
Research approach: For this, rHAp nanoparticles were first synthesized by microemulsion method and then functionalized with 2-ureido-4[1H]-pyrimidinone (UPy) groups. Moreover, PCL was functionalized and converted to supramolecular structures by reacting the hydroxyl terminal groups with UPy groups. Finally, SPCL/rHAp nanocomposites were synthesized by solution casting method and their structure and properties were examined using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), universal testing machine and simulated body fluid (SBF).
Main results: According to the results, microemulsion is an efficient procedure for the synthesis of rod-like nanoparticles with high phase purity. On the other hand, based on the results, it is possible to functionalize these nanoparticles with UPy. Tensile test showed that by incorporation of these modified nanoparticles into SPCL, a significant increase in both elastic modulus and tensile strength can be observed. In fact, while the initial PCL was a waxy solid, modification with UPy and then incorporation of modified nanoparticles made it an elastic material. Finally, the obtained results indicated high bioactivity of supramolecular nanocomposites compared to the sample without filler. Therefore, supramolecular SPCL/rHAp nanocomposites with bioactive properties and dynamic character can be used as a suitable replacement for bone tissue defects.
Volume 6, Issue 1 (10-2015)
Abstract
Nanotechnology involves technological research and development in spaces at the range of 1 to 100 nanometers, and in this technology, very small and atomic scale particles are created and handled. Plant extracts can be used as a green method for the synthesis of silver nanoparticles. In this study, the biosynthesis of silver nanoparticles was performed using extracts of sesame (Sesamum indicum) seeds. Silver nitrate was added to the seed extract, and then it was incubated at 30 ° C. The effects of three concentrations (1mM, 2mM and 3mM) of silver nitrate on the synthesis of silver nanoparticles were studied. The analyses of absorption spectroscopy UV-Visible, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and Inductively Coupled Plasma (ICP) were conducted to assess the production of nanoparticles. UV-Visible spectroscopy analysis and the peak at 420 nm indicated the occurrence of nanoparticles in the extract. TEM image determined that the nanoparticles were spherical with average size of about 14 nm. XRD analysis showed the nano-crystals synthesized by the extract, and Inductively coupled Plasma (ICP) determined the conversion percentage of silver ion into silver nanoparticle as approximately 99.61 percent.
Volume 6, Issue 1 (10-2015)
Abstract
Magnetotactic bacteria can be affected by Earth's magnetic field orientation. They have been observed various forms of cocci, bacilli and spirilla. These bacteria make magnetosomes affected by the magnetic field and its orientation as part of the iron is stored. In this study, the presence of magnetotactic bacteria in different parts of Iran with features freshwater pearls saline containing iron mine in Zanjan, Persian Gulf, Mighan and Qom wetlands was investigated. Sediments and water collected were put under magnetic field. Results showed that all types of isolated bacteria were, Gram-negative and shapes to bacillus, spirillum and coccus. The magnetic field in the capillary tube containing a magnetotactic bacterium that responds was observed to magnetic field. Mighan and Qom wetlands and Zanjan's iron mine samples have more cases of magnetotactic bacteria,were studied in particular. Transmission electron microscopy images of iron nanoparticles were visible within it. Results molecular analysis, sequencing and BLAST in NCBI website showed in sample Znjan's iron mine there is Magnetospirillum magnetotacticum strain. Higher concentrations indicate of iron nanoparticles in the sample compared to the Mighan wetland with iron mine, that the abundance of iron ions alone did not increase the level of magnetic nanoparticles of Fe by bacteria.
Volume 6, Issue 1 (6-2022)
Abstract
Research subject: This study demonstrates a synthetic strategy for the preparation of porous SiO2 for adsorption applications using natural and waste materials from rice husks which are functionalized with polymer dendrimer molecules and surface amino groups as the source of biosilica and were investigated to remove divalent cadmium ions from aqueous solutions.
Research approach: Porous silica nanoparticles with a mean diameter of 45 nm were successfully fabricated from rice husk (RH) biomass via a multistep method. During the first step, sodium silicate is extracted from rice husks. Then, cetyltrimethylammonium bromide, HCl, and acetic acid were added to the sodium silicate solution, and the resulting mixture was sonicated. After the hydrothermal reaction, the collected samples were calcinated to obtain silica nanoparticles. These synthetic nanoparticles were identified using various techniques such as Fourier-transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, field emission scanning electron microscopy, nitrogen adsorption-desorption analysis and dynamic light scattering analysis. Then, the adsorption kinetics and the effects of synthetic nanoadsorbents dosage on the removal of divalent cadmium ions were investigated. The effect of contact time on cadmium adsorption and recyclability of adsorbent was also investigated.
Main results: The results show that there is no significant reduction in the performance and activity of this nanosorbent in the adsorption of metal ions after 6 times of recycling and reuse. The excellent performance of this nanosorbent in the removal of metal ions is due to its high porosity, active surface amine groups and high surface-to-volume ratio.
Volume 6, Issue 1 (6-2022)
Abstract
Oil extracted from the underground oil reservoirs contains heavy hydrocarbons.Heavy hydrocarbons include waxes,asphalts and resins that can appear as solids in compounds,which waxes are of particular importance.Changes in factors such as temperature,pressure,compounds of light components in petroleum compounds,etc.Cause the formation of solid paraffin wax deposits in these compounds.The wax precipitate formed mainly contains paraffins,naphthenes and to a lesser extent aromatics.The formation of these sediments in the first stage can block the underground pores, reduce their permeability and reduce the efficiency of oil extraction.In the next stages,the formation of deposits will lead to many problems. For example,it can clog pipes and increase flow resistance, resulting in a drop in flow pressure and,in addition to increasing the power required to pump fluid, cause premature depreciation of the facility.The issue of wax sediment formation and the factors affecting it have been discussed by researchers for many years and different methods have been studied to control it.In this project,by examining 1 nanoparticle of SiO2,as chemical inhibitor, acceptable results were obtained in reducing the wax appearance temperature(WAT).First,using differential scanning calorimetry analysis,a temperature of 250C was obtained for the crude oil cloud point.Then,by adding nanoparticles in different concentrations,this temperature was significantly reduced for different amounts of nanoparticles.Analysis of polarized optical microscopy also shows the change in structure of wax crystals to a disk like after the addition of nanoparticles. To investigate the flow behavior of crude oil,the apparent viscosity parameter was used at shear rates of 0.01,0.1 and 1 rpm and higher and lower temperatures of WAT temperature.Then,using wax deposition of oil samples by two analyzes of X-ray diffraction(XRD) and scanning electron microscopy(FESEM) with EDAX additive to study the dispersion of nanoparticles in wax deposits and changes resulting from the addition of nanoparticles in depositions was paid.In this regard,according to X-ray diffraction analysis,it was found that the nanoparticles had no chemical interaction with wax molecules,but was a confirmation of the results obtained in the analysis of differential scanning calorimetric analysis.The layered structure of the wax precipitate by adding nanoparticles to a fine-grained structure was also one of the results of scanning electron microscopy analysis.
Volume 6, Issue 1 (6-2022)
Abstract
Research Subject: In this study, Thiourea-functionalized super-paramagnetic nanoparticles were used as a heterogeneous catalyst in the Petasis-Borono Mannich reaction.
Research approach: In the first stage of this study, Fe3O4@SiO2 nanoparticles were synthesized as spherical core-shell nanoparticles such that Fe3O4 particles were considered as the core. Then in the next step, the characteristics of surface functional groups, crystal structure, magnetic properties, size and surface appearance of nanoparticles and the process of functionalizing the structure in layers, using infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) were examined, identified and analyzed. Then, to evaluate the efficiency of the structure, it was used as a catalyst in the Borono-Mannich reaction of potassium potash. Infrared spectroscopy (FT-IR) and hydrogen nuclear magnetic resonance spectroscopy (HNMR) were used to investigate the structure of the products.
Main results: The IR spectroscopy results showed that the peaks appearing in 568 cm-1 and 670 cm-1 were related to iron-oxygen bond, the peaks in 1092 and 800-950 cm-1 were related to silicon-oxygen bond, which indicates the formation of silicon layer on nanomagnetic particles and the validity of the reaction products. The results also showed that the amount of saturated magnetite in about 23 emu/g increased with increasing complex ligand. X-ray diffraction analysis showed that the index peaks of (2θ= 21.25˚, 37.29˚, 43.73˚, 52.56˚, 65.09˚, 69.73˚, 76.81˚) were realized and for certainty of the formation of the desired magnetic nanoparticles in crystalline phase were used. The results of SEM analysis showed the structure of nanoparticles in a spherical shape and EDX analysis confirmed the presence of elements in the structure which included sulfur. Also, the thermogravimetric analysis index showed approximately 7% decomposition coefficient. The first, second and third decomposition were observed 1% by weight (60°C), 5% by weight (200 to 300°C) and 1% by weight (350 to 700° C), respectively. The highest yield of 68% was measured with 40 mg catalyst in acetonitrile. The structure of thiourea was properly stabilized in a magnetic nanocatalyst.