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Fiber production in nanoscale prepares high surface contact for fibers and leads to the improvement of their properties with respect to other fibers. A convenient and effective method for nanofiber production with different diameters is electrospinning. Various effective parameters on electrospinning processes, including environmental, equipment, and solution variables can produce fibers with different morphologies. PVA has been used in various fields of applied research because of its high thermal stability, biocompatibility, non-toxic and solubility in water. The published reports indicated that properties of the PVA are improved with the addition of bentonite. In this research, to prepare PVA/nano-bentonite nanofiber membrane, the optimum amounts of three effective variables on the above-mentioned processes were determined. According to the obtained results, the voltage of 11 kV, the feeding rate of 0.5 mL/h and bentonite concentration of 3% w/w were optimum conditions for the process of PVA/nano-bentonite nanofiber composite production. In this condition, the average diameter of produced nanofibers was 243 nm with the standard deviation of 0.0551 and the tensile strength of 7.64 MPa. The results showed that the addition of bentonite to PVA increase intensity of nanofibers and decrease the diameter of nanofibers from 308 nm to 243nm.Therfore, the produced PVA/bentonite nanofiber composite is a good membrane for water treatment.

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The porosity of electrospun nanofibers web is a significant parameter affecting various areas of nanofibers applications. Thus, at first, the effect of most effective parameters, the concentration of polymer solution and flow rate, on the diameter of polyvinyl alcohol nanofibers, as a dissolving component, were investigated. Afterward, the hybrid web of polyamide 6/polyvinyl alcohol (PA/P) was prepared via a two-sided dual-nozzles electrospinning method. The morphology, diameter, pore size of nanofibers web and the effect of dissolving constituent were studied based on images of the scanning electron microscope. To measuring the porosity of nanofibrous webs, three practical and straightforward methods that have been proposed in the literature were utilized. It was observed that when one component was dissolved, the diameter of the resultant web was decreased, and the porosity has been reduced to about 70% based on the best selected method of porosity. Additionally, the average pore size of electrospun PA6 webs has been decreased about 30-58% relative to the original hybrid webs.

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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.

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According to the novel achievements, nanotopography and steric geometry of the microenvironment around the cells have a drastic role on their fates. Hence, fabrication of biocompatible nanostructures as the scaffolds for the cell culture and in the next step, accurate determination of their physical and geometrical characteristics is widely considered. Despite of broad utilization of Atomic Force Microscopy to investigate topological traits of sophisticated nanopatterns; its capability to characterize electrospun nanofibers has not been studied inquiringly. In the present research, chitosan nanofibers which were successfully electrospun at the optimized conditions were then evaluated using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) respectively. The results suggested that recruitment of both of these techniques have their own advantages and disadvantages. As the first noticeable issue, while the sample preparation and scanning procedure in SEM imaging may disrupt native structure of fibers, probing the sample by AFM doesn't need any pre-imaging treatment. The main application of SEM in analysis of nanofibrillar structures is the rapid survey of nanofibers shape, orientation, diameter and consistency. In the other side, three dimensional imaging by AFM makes it possible to determine whole surface roughness, roughness along fibers and woven tissue thickness. Furthermore, regarding some technical advices, AFM can be used to estimate nanofibers average diameter as well as SEM.

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The aim of this article is to investigate the effects of Nylon nanofiber in carbon- epoxy composites properties under double cantilever beam test by Non-destructive Acoustic Emission testing. In order to increase tougher of carbon- epoxy composite, Nylon nanofibers were placed in to the midplane interface of carbon- epoxy laminates. In order to better identification of the effects of Nylon nanofibers and more accurate clustering of Acoustic emission parameters were used combining of k-means algorithm and Genetic algorithm for clustering. Acoustic emission descriptors like Amplitude, Duration, Count, Acoustic Energy and Rise time were used in order to survey identification of effects of nanofibers. The results of clustering of Acoustic emission signals that obtained from carbon- epoxy composite and carbon- epoxy nanomodified composite shows that the presence of Nylon nanofibers increase the tougher of carbon- epoxy composite and delayed damage mechanisms. This method of clustering is a good fit between acoustic signals and damage mechanisms and time of events. Cumulative events of Acoustic emission Amplitude obtained from damage mechanisms of both composite are in the same range and Acoustic emission duration of carbon-epoxy is more than carbon-epoxy nanomodified composite.

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Protein-based carriers have several advantages over lipid, carbohydrate, synthetic polymers and inorganic colloidal carriers in terms of biodegradability, availability, high capacity of drug transplantation. Electrospinning is a process that uses electric fields to spin fibers with diameters ranging from hundreds to tens of nanometers. Zein is the major storage protein of maize. Vancomycin is a broad spectrum antibiotic that acts against gram-positive bacteria. The purpose of the present study was to evaluate the properties of nano-fibrous membrane containing vancomycin antibiotics and to study release and antibacterial properties. Electrospinning method was used to prepare a polymer matrix of a zein nanofiber containing vancomycin antibiotic. The physical properties of the fibers, the method of drug release and the antimicrobial activity of vancomycin loaded fiber were investigated. The morphology of the nanofiber was confirmed using scanning electron microscopy and the formation of uniform filamentary fibers was confirmed. The results of Fourier transform infrared indicated no interaction between zein and vancomycin. The DSC results indicated that vancomycin was physically in amorphous state. The results showed that after 168 h, about 55% of the loaded vancomycin on the fibers was released. A significant difference was observed between the rate of drug release at different times (p <0.05). There was also a decrease in the number of bacteria encountered with vancomycin loaded zein fibers compared to non-loaded zein fiber and control samples. Keywords: Nanofiber, Zein, Vancomycin, Electrospinning, Drug delivery

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Objective: In this study we introduced an RGD-containing peptide of collagen IV origin that possesses potent cell adhesion and proliferation properties. This peptide was immobilized on a nanofibrous polycaprolactone/gelatin scaffold after which we analyzed human bone marrow-derived mesenchymal stem cells (hBMSCs) adhesion and proliferation on this peptide-modified scaffold. Methods: Nanofibrous scaffold was prepared by electrospinning. The peptide was synthesized by solid-phase peptide synthesis and immobilized on electrospun nanofibrous a polycaprolactone/gelatin scaffold by chemical bonding. Native and modified scaffolds were characterized with Scanning Electron Microscope (SEM) and Fourier-Transform Infra-red Spectroscopy (FTIR). Adhesion and proliferation of hBMSCs on native and modified scaffolds were analyzed by the Methylthiazol Tetrazolium (MTT) assay. Results: SEM images showed that electrospun scaffolds had homogenous morphology and were 312±89 nm in diameter. There was no significant difference in scaffold morphology before and after peptide immobilization. FTIR results showed that the peptide was successfully immobilized on the scaffold. Based on MTT assay, cell adhesion studies indicated that peptide immobilization improved cell adhesion on RGD-modified scaffolds at all corresponding time points (pConclusion: This novel peptide and modified nanofibrous scaffold, having improved cell adhesion and proliferation properties, can be used for tissue engineering and regenerative medicine by using hBMSCs.

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In the present study, Azivash leaf gum (Corchorus olitorius L.) was used for the first time with the help of an electroporation technique in the presence of poly-vinyl alcohol as a natural nanofibre. At first, the effect of different concentrations of Azivash gum aqueous solution (2, 2.5 and 3 g / l) with polyvinyl alcohol (P70: G30, P60: G40, P50: G50 and P0: G100) on viscosity and electrical conductivity as the main soluble parameters was studied. The results showed a significant increase in viscosity concentration with gum concentration and volume ratio of polyvinyl alcohol (p <0.01). Regardless of the concentration of Azivash gum, by increasing the ratio of gum to polyvinyl alcohol, the electrical conductivity increased significantly (p <0.05). In the study of shear stress-shear rate of Azivash gum and polyvinyl alcohol solutions, pseudoplastic behavior was confirmed. Investigating the fitting of rheological data with Herschel-Balkly models, power law and casson showed that the Herschel-Balkly model with the highest R² / RMSE is desirable to describe the flow behavior. The values ​​of the flow index and consistency coefficient were determined by the model. After the electrospining of azivash leaf gum-polyvinyl alcohol in a constant condition (voltages of 18 kV, volumetric flow rate of 0.7 ml/hr and needle distance to a collector plate of 12 cm), by microstructure analysis and based on the morphology of bead-free fibres, the Azivash gum formulation at 2 g / L concentration and the mixing ratio of 70:30 with polyvinyl alcohol was selected as the most suitable formulation with a mean nanofiber diameter of 90 nm. Based on FTIR resulrs, addition of gum to polyvinyl alcohol caused an increase in peak intensity due to carbonyl and hydroxyl groups glycosidic vibrations. Also, the thermal stability of the gum nanofibers of Azivash improved in the presence of polyvinyl alcohol.

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Abstract  
 

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Objectives: CtxB (Cholera toxin B subunit) contributes to a vaccine's efficacy by stimulating production of the anti-CtxB antibody. Various attempts have been made to increase production of this antibody. Chitosan is a mucoadhesive polysaccharide that has tremendous potential for oral vaccine delivery in terms of its exclusive features that include biocompatibility, biodegradability, high charge density and non-toxicity. We investigated the potential for chitosan nano­fibers and nanocapsules as novel carrier systems for the oral delivery of CtxB. Methods: Antigen-containing chitosan nanofibers were prepared by electrospinning a chitosan/AcOH solution. Encapsulation of the antigen inside the chitosan nanofibers was confirmed through infrared spectroscopy analysis (FTIR). Guinea pigs were immunized with free antigen and CtxB antigen or antigen alone by direct administration of antigen-containing chitosan nanofibers into the buccal cavity. Serum immunoglobulin G (IgG) and intestinal immunoglobulin A (IgA) antibody responses were determined Results: The results indicated that antigen in the chitosan nanofibers or nanocapsules elicited very high IgA and IgG responses. No detectable IgA and IgG responses were obtained after oral immuniza­tion with CtxB. The results of the antibody titer were analyzed using the ANOVA and LSD tests. Conclusion: CtxB inside the nanofiber increased antibody production when administered orally. This system might be used for delivery of other antigens.

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Biodegradable polymers have supplied most of common packaging materials because they present several desired features. The purpose of this study was to prepare and investigate the physicochemical properties of carboxymethyl cellulose based nanocomposite film containing inulin with three different concentrations (0, 10 and 20%) and cellulose nanofiber in three levels (0, 2.5 and 5%). Thickness, Water vapor permeability (WVP), Water contact angle, mechanical properties, field emission scanning electron microscopy (FE-SEM) and X-ray diffraction were evaluated for film samples. WVP decreased with adding cellulose nanofiber and inulin and water contact angle increased significantly (p <0.05). The mechanical properties were also improved by adding the cellulose nanofibers. Whereas inulin had a negative effect on mechanical properties by decreasing tensile strength (UTS) and increasing elongation to break (ETB), this effect of inulin was compensated by cellulose nanofiber in the composite films containing inulin and cellulose nanofiber. The FE-SEM and X-ray diffraction results showed that the cellulose nanofiber and inulin were dispersed in the polymeric matrix and formed a dense and compact structure in compared to the control film. Results showed that cellulose nanofiber and inulin improve the properties of carboxymethyl cellulose based nanocomposites and the obtained film can be used as a new choice in food packaging.

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There is a growing interest in bioactive packaging systems due to their potential for the extended shelf life of food products. In this way, to produce probiotic nanocomposite whey protein isolate-polydextrose film containing cellulose nanofiber and Lactobacillus plantarum probiotic bacteria and evaluation of its antimicrobial effect on beef shelf life during storage time, different concentrations of polydextrose (0, 10 and 20 wt / wt% whey protein isolate) and cellulose nanofiber (0, 2.5 and 5 wt / wt% whey protein isolate) were used for film preparation. Effect of variables on physical properties of the film (thickness, moisture absorption, water contact angle, and color properties) and effect of optimal film antimicrobial properties on enhancing the beef shelf-life during 8-day storage time in refrigerated conditions was examined. The results showed compatibility between the protein matrix of whey protein isolate, cellulose nanofiber and polydextrose. The use of polydextrose and cellulose nanofiber had a significant effect on increasing the film thickness, water contact angle, color changes and decreased the moisture absorption of the film. The results of covering the meat samples with the optimum film indicated a significant decrease in the growth of aerobic mesophilic bacteria, psychrotrophic and coliform bacteria during storage time. Finally, the results showed that the application of cellulose nanofiber and polydextrose in the film produced from whey protein isolate could improve the shelf-life of  beef compared to the uncovered meat sample by creating a bioactive food packaging.
 

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Advancement in the production processes of nanostructures with appropriate formula characteristics provides the production of stable nanoparticles with the ability to be used in the food industry. Microencapsulated bioactive compounds can be integrated into electrospun fibers to achieve greater stability of nanoparticles against heat and light, which leads to increased storage time. In the present study, composite nanofiber layers were made from mucilage extracted from Salvia macrosiphon L. seeds using electrospinning. The nanocomposite of nanofibers was prepared from polyvinyl alcohol/rice bran protein isolate/ Salvia macrosiphon L. seed mucilage in different ratios. Then the morphology and FTIR spectroscopy were investigated. The average diameter of the produced nanofibers is about 40 nm and the coefficient of variance is 13%, which showed that the diameter of the fibers is relatively uniform. Increasing the concentration of the mucilage solution and the constant percentage of polyvinyl alcohol significantly increased the diameter of the nanofibers. In the next step, vitamin D3 was encapsulated in polyvinyl alcohol nanofibers and rice bran protein concentrate. FTIR results confirmed the presence of vitamin D3 in the prepared nanofibers. At higher concentrations of phenolic compounds, with the increase in the number of hydroxyl groups of aromatic rings in the reaction medium, the inhibitory power of mucilage free radicals increased. The composition of nanofibers in the spectroscopic graphs showed that there are two strong peaks in the range of 1454 and 1743 CM-1 from vitamin D3 in the nanocomposite and microcoated samples which show the stretching vibrations related to the C=C group in the aromatic rings of phenolic compounds. Based on the findings, bioactive compounds to increase access to vitamin D3 can be enclosed in electrospun nanofibers of Salvia macrosiphon L. mucilage/polyvinyl alcohol/rice bran protein concentrate.