Application of electrospun nanofibrous scaffolds has received immense attention in tissue engineering. Fabrication of scaffolds with appropriate electrical properties plays a key role in neural ...tissue engineering. Since fibers orientation in the scaffolds affects the growth and proliferation of the cells, this study aimed to prepare aligned electrospun conductive nanofibers by mixing 1 %, 10 % and 18 % (w/v) doped polyaniline (PANI) with polycaprolactone (PCL)/poly lactic-coglycolic acid (PLGA) (25/75) solution through the electrospinning process. The fibers diameter, hydrophilicity and conductivity were measured. In addition, the shape and proliferation of the nerve cells seeded on fibers were evaluated by MTT cytotoxicity assay and scanning electron microscopy. The results revealed that the conductive nanofibrous scaffolds were appropriate substrates for the attachment and proliferation of nerve cells. The electrical stimulation enhanced neurite outgrowth compared to those PLGA/PCL/PANI scaffolds that were not subjected to electrical stimulation. As polyaniline ratio increases, electric stimulation through nanofibrous PLGA/PCL/PANI scaffolds results in cell proliferation enhancement. However, a raise more than 10 % in polyaniline will result in cell toxicity. It was concluded that conductive scaffolds with appropriate ratio of PANI along with electrical stimulation have potential applications in treatment of spinal cord injuries.
Color selection for a camouflage pattern is a substantial part in designing an effective camouflage pattern. Current color selection methods are often based on the prevailing colors of digital images ...captured from a scene. However, color extraction from digital images has shown a major difference between the pattern color and the real environment colors. In this article, we present a more precise approach to camouflage color selection based on the spectrophotometric data of dominant objects in a scene. To this end, the dominant objects of a grassland scene were identified. The spectral reflectance of the dominant objects was measured and the percentage of each of them occurred in the scene was estimated. Then, the chromatic values of dominant objects were inserted into an existing camouflage pattern based on the occurrence of each dominant object in the scene. The performance of the obtained colors was assessed by calculating the color difference between the printed camouflage pattern and the dominant objects of the scene. The results showed that using a portable spectrophotometer instead of using a digital camera is more accurate for camouflage color selection and reduces the color difference from the surrounding environment. Furthermore, our method guarantees the absolute similarity between camouflage colors and terrain colors without using camouflage evaluation indexes or photo‐simulation assessment.
Distance metrics for very large color differences Abasi, Saeedeh; Amani Tehran, Mohammad; Fairchild, Mark D.
Color research and application,
April 2020, 2020-04-00, 20200401, Letnik:
45, Številka:
2
Journal Article
Recenzirano
Small, supra‐threshold color differences are typically described with Euclidean distance metrics, or dimension‐weighted Euclidean metrics, in color appearance spaces such as CIELAB. This research ...examines the perception and modeling of very large color differences in the order of 10 CIELAB units or larger, with an aim of describing the salience of color differences between distinct objects in real‐world scenes and images. A psychophysical experiment was completed to compare directly large color‐difference pairs designed to probe various Euclidean and non‐Euclidean distance metrics. The results indicate that very large color differences are best described by HyAB, a combination of a Euclidean metric in hue and chroma with a city‐block metric to incorporate lightness differences.
Since, during different physical activities, garments should have the ability to be extended due to the body movements, it is a necessity for it to have suitable elasticity and recovery in order to ...provide comfort for the wearer. Therefore, the dynamic elastic recovery behavior of the fabric is very important and indicates the resistance of the garment and its immediate response to body movements. In this research, four weft knitted fabrics with different elastic properties have been studied. Besides the analysis of the tensile properties of fabric, the influence of fabric elasticity, strain percentage and the number of loading cycles on the dynamic elastic recovery has been investigated. Moreover, the fatigue and residual percentage and residual strain were calculated. Furthermore, the exerted pressure by the garment on the body, was measured throughout wearing leggings with different sizes. Finally, the relationship between elastic recovery and the amount of exerted pressure was investigated. The results showed that in both course and wale directions, by increasing the applied strain level, the dynamic elastic recovery of fabric decreased. Moreover, it was revealed that the fabric with more elasticity had better elastic recovery. The higher elasticity of the fabric led to higher and lower static and dynamic pressure, respectively. In addition, by increment of dynamic elastic recovery of fabric, lower pressure was applied on the body during walking and running which indicates to the improvement of body movement comfort.
Manipulating existing camouflage patterns is a challenging issue in the process of camouflage pattern design. In this article, we present an effective approach based on the neural style transfer ...method to generate a hybrid camouflage pattern by manipulating two given camouflage patterns. Using a convolutional network trained on image recognition, content and style are represented by the correlations between feature maps in several layers of the network. In this regard, we utilized different commonly used camouflage patterns as content and style images. Then, by performing the style transfer algorithm on selected camouflage patterns, a new hybrid camouflage pattern was generated. The hybrid pattern inherits the appearance features of the content and the style images. Also, the colors of the hybrid pattern were controlled by carefully selecting the input colors. It was concluded that the proposed method is useful for adding or deleting some features of an existing camouflage pattern. In fact, it is a professional tool for pixelating, depixelating, blurring, and gradual coloring of camouflage patterns. Furthermore, we demonstrate the effectiveness of hybrid camouflage patterns using visual assessment. The results of the subjective assessment show that the proposed method is efficient for generating successful camouflage patterns.
Hybrid pattern generation using camouflage style transfer technique.
Considering the efficient TiO2 structure on enhancing its photocatalytic behavior is of great interest in recent years. Meanwhile, inhibiting the filtration process for detachment of the catalyst ...from the purified solution is very advantages. To approach this purpose, TiO2 nanofiber yarns were successfully fabricated through the electrospinning technique using two oppositely charged nozzles followed by the calcinations process from a solution containing titanium precursor and polyvinyl acetate (PVAc) as the supporting material. The introduced nanofiber yarns eliminate the ultrasonic and centrifuge steps required in photocatalytic tests of nanoparticles and electrospun nanofibers. The results show that this new catalyst's structure maintains its shape during the photocatalytic degradation process and can be easily removed from the purified water.
Hypothesis: The physical properties of electrospun nanofibrous mats have a significant effect on the behavior of electrospun mat in interaction with other surfaces, as well as on its efficiency in ...various applications. Therefore, determining and predicting these structural properties using controllable factors in the electrospinning process are of particular importance. On this basis, in the present research each of the structural properties of nanofibrous mat, including mat porosity, diameter and porosity of fiber, were estimated using mathematical relationships. Also, the prediction and optimization of input factors and the porosity of the mat and fibers were performed using the response surface methodology (RSM). Methods: Poly(lactic-glycolic-acid) was used to produce nanofibrous mats. After the determination and optimization of the electrospinning process factors, which influence the structural properties of nanofibrous mats, 18 types of mats were prepared. Considering the combined effect of three electrospinning factors, including solution concentration, humidity and collector linear speed, RSM and regression methods were used to optimize and model the relationship between variables and mat properties, respectively. Findings: Based on the mathematical relationships between the input factors and the structural characteristics of the mat, it can be revealed that the concentration is the most effective factor on the fiber diameter and mat porosity, and the collection speed is the most effective factor on the fiber porosity. According to the RSM models, the optimized values for the initial factors of concentration, humidity and collection speed based on the model designed for fiber porosity are 2% (w/v), 45% and 0.4 m/s, and based on the model designed for mat porosity are 3% (w/v), 45% and 2.4 m/s, respectively. The predicted optimized values of fiber porosity and mat porosity are 0.342% and 0.989%, respectively, which are not much different from the experimental values obtained from these points. The nanofibrous mat introduced by each of these models has created the most porosity.
