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Aims: Recently, polymer-based nanofibrous scaffolds have attracted great attention due to their significant antibacterial properties in the field of dermatological applications. In this study, a polycaprolactone-based nanofibrous scaffold has been fabricated using the electrospinning method. The aim of this study was to evaluate the antibacterial effect of electrospun nanofibrous structures. Materials and Methods: In this experimental study, the structure and bacterial attachment on polymeric nanofibrous scaffolds were studied by Scanning Electron Microscopy (SEM). In addition, antibacterial properties of nanofibrous scaffolds were studied on two gram-negative bacteria of Escherichia coli and Pseudomonas aeruginosa and two gram-positive bacteria of Staphylococcus aureus and Streptococcus mutans, using microdilution method and biofilm assay. Moreover, MTT assay was performed on HeLa and human fibrosarcoma cell line (HT1080) cancerous cell lines to evaluate the cell viability.
Findings: The results of this study showed that nanofibrous scaffold revealed a significant antimicrobial and anti-biofilm formation effect on all of the studied bacterial strains, but in microscopic observations and microdilution assay was observed on Pseudomonas aeruginosa in 1mg/ml of nanofibrous scaffold extract concentration, while the major effect in biofilm assay was observed in 8µg/ml of extract concentration. Moreover, the cell viability studies showed that the most significant effect was shown on HT1080 cell line which has drastically decreased by 40% after 48 hours in comparison with the control.
Conclusion: These results show that electrospun nanofibrous PCL-based scaffolds are potentially promising for dermal tissue engineering applications, due to anti-biofilm effects and capability of reducing the number of cancerous cells in the wound site.

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Since one of the main problems in bone tissue repair is the bacterial infections, recently the development of drug-eluting nanocomposite scaffolds for bone regenerative medicine applications has attracted significant attention. In this study Polycaprolactone (PCL)-based composite scaffolds containing 10vol% of titanium dioxide nanoparticles (~21nm), and bioactive glass particles (~6µm), were prepared without drug and also loaded by Tetracycline hydrochloride (TCH) antibiotic (0.57, 1.15 mg/mL) through solvent casting method for bone tissue engineering applications. Structural characterizations based on Scanning Electron Microscopy (SEM), and FTIR analysis were utilized to study the chemical bonds of glass/ceramic particles, and antibiotic crystals on the surface. In addition, in vitro cytotoxicity, and antibacterial analysis were performed by MTT, and Agar well-diffusion assays, respectively. In this study polymeric and composite scaffolds were fabricated with TCH clusters decorated on the surface. It was shown that the bioactive glass/PCL scaffolds loaded by 0.57 mg/mL of TCH revealed significant antibacterial effect, despite the acceptable cell viability. These scaffolds seem to be of interest as a potential candidate in drug-eluting scaffolds for bone tissue engineering applications.

 

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The human amniotic membrane (HAM) is one of the rare allograft tissues that are in use in clinical trials. Biocompatibility, antibacterial effect, low immunogenicity, and scar prevention are properties that have made HAM attractive for tissue engineering (TE) applications, for example, as a cell carrier, injectable hydrogel, and cell culture substrate. In this research, the effect of digestion time on the structure, gelation kinetics, rheological and biological properties of amniotic membrane-derived hydrogels was studied. The results determined that digestion with pepsin should be performed at least for 24 h.  Prolonging the digestion time to 72 h increased the shear modulus, fiber diameter, and gelation rate. Cytocompatibility assays with L929 fibroblast cells showed that the digestion time had no effect on the cell toxicity of the hydrogels. However, cell proliferation was improved due to preserved constitutive bioactive molecules. The results of this research can be used to develop amniotic membrane-derived hydrogels for TE applications.

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Abstract: Considering the seismicity of most of the areas in Iran, it is inevitable to confront the earthquake because of its major property and life damages. Therefore researchers put a great effort on designing and strengthening against earthquake. The researches conducted so far for improving the reinforced concrete structures using different types of steel braces and analytical studies and widespread experiments has been done for confronting destructive effects of earthquake on structures, results show the proper effectiveness of different mechanisms of inactive seismic control of structures as an efficient option for confronting the earthquake forces. Of different control methods, using friction damper could be counted as one of the best methods for improving the seismic behavior of current structures, as it uses a simple mechanism and doesn’t need specific materials or technology. By using friction dampers both the rigidity and the structure’s hysteresis energy loss ability is increased. These dampers by their inelastic behavior in different points of the structure cause the loss of incoming energy of earthquake. Also in high importance structures, by selecting the proper design parameters, it is possible to prevent the main structural members to enter the inelastic behavior limit which causes local damages to some parts of them or minimize that. This system was first introduced by Pall and March in 1982. The mechanism of this system is creating slippage friction surfaces at the intersection of braces. For building frames, these dampers could be used in crossed tension bracing, single diagonal bracing and Chevron bracing. The first model of pall friction damper was tested in chevron bracing against earthquake in Eaton Building in Canada. The purpose of this study is to investigate the role of Pall friction dampers in reducing structural response during the earthquake. Therefore, modeling of the damper is based on the model used by the Pall Corporation in Eaton Building. The functioning of this damper is by generating friction under lateral shear force which causes the movement of the damper and generation of slippage in it. Therefore, three concrete moment frames with 5, 8 and 10 stories, have been designed according to the Iranian National Codes. Using SAP2000, v14, several static nonlinear analyses were done to get the performance point of frames on the basis of the capacity spectrum method. Adding chevron braces to the mid span, the target displacement of frames were determined. Considering the fact that none of the braced moment frames satisfied the Life Safety criteria under Design Based Earthquake, Pall friction dampers have been added to the frames and static nonlinear analysis were done by several slip loads such as 1%, 10%, 25%, 50%, 75% and 100% of frame weights. Evaluation showed that in optimum slip Load, the performance level of the frames improves.

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In recent years, significant efforts have been focused on advancements of novel biomaterials based on natural polymers and utilization of efficient methods such as skin tissue engineering for wound treatment. In this study, a 3D printed polycaprolactone (PCL) scaffold coated via immersion in a 1:4 blend of 40% silk fibroin from Bombyx mori cocoons and TEMPO-oxidized was developed. The pore size and the porosity were 180 µm and 85%, respectively. The results demonstrated an enhancement in exudate absorption (swelling and water uptake of 1342% and 80%, respectively), improvement in storage modulus (G’) from 500 to 4000 Pa, as well as viscoelasticity up to 60%, which all are favorable for wound dressing applications. Moreover, the wettability and biodegradability studies revealed an overall increase in contact angle and degradation rate of 19.9°±3, and 95%, respectively. Cell viability and migration studies on fibroblastic cells (L929) using MTT assay, DAPI/ Phalloidin staining, and scratch test showed over 90% viability up to 7 days and complete scratch repair within 24 hours. These findings show that 3D printed PCL scaffolds coated with silk fibroin and oxidized nanocellulose are promising for wound healing applications and might pave the way to natural polymer-based wound dressings.
 

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This study was aimed at evaluating the flow behavior characteristics of yogurt enriched with fish oil (FO) microcapsules prepared by complex coacervation method. FO was microencapsulated in gelatin-acacia gum coacervates. Then, the microcapsules were dried, and yogurt was produced from the milk enriched with microcapsules powder. Rheological characteristics (as measured using a rotational viscometer) of yogurt were evaluated in the shear rate range of 0.262-7.86 s^-1 at 6˚C during 21 days of storage. Power Law model was used for calculation of consistency coefficient and flow behavior index of yogurt. As compared to the control, the enriched yogurt had higher apparent viscosity. Consistency coefficients of the enriched and the control yogurts were in the range of 24.42-28.82 and 15.31-17.76 Pa sⁿ, respectively. Yogurt samples showed a non-Newtonian shear-thinning flow behavior. Addition of FO microcapsules to yogurt may be useful for improving its health-promoting effect and consistency.

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Grape fruit contains some nutrients and high amounts of biologically active phenolic substances, but fungal decay and quality loss are important factors limiting its shelf-life for fresh-consuming and export. Rasheh vine (Vitis vinifera cv. Rasheh) is mainly grown in rainfed vineyards in the western half of Iran, and its berries are rich in anthocyanins, flavonoids and soluble solids. In this study, the effect of natural coatings of nano-chitosan and acetic acid on the post-harvest quality characteristics of Rasheh grape fruit was investigated. Nano-chitosan suspension with a particle size distribution of 5-30 nm was prepared in acetic acid solution by the conventional ionic gelation method. Grape fruits were coated by immersion in the nano-chitosan suspension (0.2%), acetic acid solution (0.5%) or distilled water (control) for 1 min and their microbial, physicochemical and sensory properties were measured during 8 weeks storage at 4 °C and 90% relative humidity. In general, the fruits coated with nano-chitosan or acetic acid had lower aerobic mesophilic bacteria count, mold and yeast count and decay percentage, and higher firmness, soluble solids, titratable acidity and vitamin C, as well as, better sensory properties, compared to the control. The nano-chitosan was more effective than acetic acid in improving the post-harvest quality and shelf life of grape fruit. No significant difference was observed in the weight loss percentage and pH values of the samples. Therefore, the nano-chitosan suspension prepared in acetic acid solution, as a natural and customer-friendly coating, is suitable for improving the shelf-life and post-harvest quality of grape fruit, but some of its beneficial effects are due to acetic acid.

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In this study, the effect of different levels of inulin (0 to 5%) and egg white powder (0 to 10%) on protein content and sensory characteristics of taste, aroma, softness, spreadability and overall acceptability of spreadable processed cheese was investigated. The results were modeled and analyzed by the response surface methodology (RSM) based on a central composite design (CCD). For all response variables, the R² values ​​of the models ranged from 0.86 to 0.99, and the values ​​of lack-of-fit factors were not significant (P >0.05); Therefore, the accuracy of the models for fitting the data was confirmed. In general, inulin decreased, but egg white powder increased the protein percentage of processed cheese. Inulin had a favorable effect on the softness and spreadability of processed cheese, but reduced the scores of taste, aroma and overall acceptability, especially at high concentration (5%). In contrast, egg white powder improved the taste, aroma, and overall acceptability of processed cheese, but reduced its softness and had little effect on its spreadability. The combination of inulin and egg white powder moderated each other's negative effects on the sensory properties of the fortified processed cheese, and ultimately improved its sensory properties compared to the control sample.

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Antimicrobial edible coatings containing plant essential oils have various advantages and are currently being used to design biodegradable packaging. In this study, cinnamon essential oil was added at concentrations of 0, 0.3, 0.6 and 0.9% to the Shahri Balangu seed mucilage solution to produce a bioactive edible coating. Strawberry samples were coated with the edible coating and their physicochemical, microbial, and sensory changes were evaluated during a 10-day storage period at 4 °C. Compared to the control sample, the use of edible coating based on Shahri Balangu seed mucilage containing 0.9% of cinnamon essential oil, significantly inhibited the changes in pH, acidity, soluble solids (13.69% vs. 43.5% increase), microbial count (3.22 vs. 3.98 log CFU/g increase), hardness (6.74% vs. 33.05%), and sensory properties (color, odor, texture, and overall acceptance) of strawberry fruit during storage. Therefore, the edible coating based on Shahri Balangu seed mucilage containing cinnamon essential oil can be used as an active packaging to improve the quality and safety characteristics of various food products.
 

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In this research, the effect of storage time on the characteristics of extensibility and consistency of processed cheese samples produced from egg white, corn oil and soy protein was investigated. In this research, firstly, in order to optimize the formulation of processed cheese from the central composite statistical design in three levels for three independent variables including soy protein isolate (0, 7.5, 15%W/V), corn oil (0, 8, 16%V/V) and egg white. Egg (0, 3, 6%V/V) was used. On the other hand, the optimal formulation of processed cheese was obtained with the objective of maximum scores of the two characteristics of extensibility and texture continuity, using the utility function method. Finally, the effect of storage in three time periods (0, 1, and 2 months) on the two characteristics of extensibility and consistency of the optimized sample texture was investigated by relying on physical changes. According to the obtained results, the effect of time on the extensibility characteristic showed that with the passage of time, the extensibility of processed cheese samples increased significantly in the negative direction. According to the results, the interaction effect of egg white/time and corn oil/time; It showed that with the passage of time (in the presence and absence of egg white and corn oil), the expandability of the produced samples increased significantly in the negative direction. Also, the effect of time on consistency properties showed that with the passage of time, the consistency of produced processed cheese samples decreased significantly. The results of this study are favorable for the development of processed cheese production and profitable dairy products containing egg white, corn oil, and soy protein. .