Experimental and Theoretical Predictions of Static Plantar Pressure of Socks with Different Stitch Lengths.

BACKGROUND: Socks are mainly used to give the foot more comfort while wearing shoes. Stitch density of the knitted fabric used in socks can significantly affect the sock properties because it is one of the most important fabric structural factors influencing the mechanical properties. Continuous plantar pressures can cause serious damage, particularly under the metatarsal heads, and it is deduced that using socks redistributes and reduces peak plantar pressures. If peak pressure under the metatarsal heads is predicted, then it will be possible to produce socks with the best mechanical properties to reduce the pressure in these critical areas. METHODS: Plain knitted socks with three different stitch lengths (high, medium, and low) were produced. Static plantar pressure measurements by the Gaitview system were accomplished on ten women and then compared with the barefoot situation. Also, the peak plantar pressure of three types of socks under the metatarsal heads are theoretically predicted using the Hertz contact theory. RESULTS: Experimental results indicate that all socks redistribute the plantar pressure from high to low plantar pressure regions compared with barefoot. In particular, socks with high stitch length have the best performance. By increasing the stitch length, we can significantly reduce the peak plantar pressure of the socks. Correspondingly, the Hertz contact theory resulted in a trend of mean peak pressure reductions in the forefoot region similar to the socks with different stitch densities. CONCLUSIONS: The theoretical results show that by using the Hertz contact theory, static plantar pressure in the forefoot region can be well predicted at a mean error of approximately 9% compared with the other experimental findings.

Plantar Static Pressure Distribution in Normal Feet Using Cotton Socks with Different Structures.

BACKGROUND: The major goal of investigating plantar pressure in patients with pain or those at risk for skin injury is to reduce pressure under prominent metatarsal heads, especially the first and second metatarsals. In research, the insole is used to reduce plantar pressure by increasing the contact area in the midfoot region, which, in turn, induces an uncomfortable feeling near the arch during walking. It is deduced that sock structure can redistribute plantar pressure distribution. METHODS: Seven sock types with seven structures (plain, single cross tuck, mock rib inlay, cross miss, mock rib, double cross tuck, and double cross miss) for the sole area were produced. A plantar pressure measurement device was used to measure plantar static pressure in ten participants. The barefoot plantar pressure distribution was compared with the plantar pressure distribution with socks. RESULTS: In the seven sock samples, the mean plantar pressure of the cross miss and mock rib structures at high plantar pressure zones (toe and first through fourth metatarsal bone regions) were decreased, and, as a result, the pressure shifted to relatively low pressure zones (fifth metatarsal bone and midfoot regions). CONCLUSIONS: These results indicate that wearing socks with cross miss and mock rib structures will reduce mean plantar pressure values compared with the barefoot condition in high plantar pressure zones. In general, the results suggest that mean plantar pressure is redistributed from high to low plantar pressure zones.

A theoretical analysis and prediction of pore size and pore size distribution in electrospun multilayer nanofibrous materials.

Electrospinning process can fabricate nanomaterials with unique nanostructures for potential biomedical and environmental applications. However, the prediction and, consequently, the control of the porous structure of these materials has been impractical due to the complexity of the electrospinning process. In this research, a theoretical model for characterizing the porous structure of the electrospun nanofibrous network has been developed by combining the stochastic and stereological probability approaches. From consideration of number of fiber-to-fiber contacts in an electrospun nanofibrous assembly, geometrical and statistical theory relating morphological and structural parameters of the network to the characteristic dimensions of interfibers pores is provided. It has been shown that these properties are strongly influenced by the fiber diameter, porosity, and thickness of assembly. It is also demonstrated that at a given network porosity, increasing fiber diameter and thickness of the network reduces the characteristic dimensions of pores. It is also discussed that the role of fiber diameter and number of the layer in the assembly is dominant in controlling the pore size distribution of the networks. The theory has been validated experimentally and results compared with the existing theory to predict the pore size distribution of nanofiber mats. It is believed that the presented theory for estimation of pore size distribution is more realistic and useful for further studies of multilayer random nanofibrous assemblies.

Three-dimensional pore structure analysis of nano/microfibrous scaffolds using confocal laser scanning microscopy.

Specific internal pore architectures are required to provide the needed biological and biophysical functions for fibrous scaffolds as these architectures are critical to cell infiltration and in-grows performance. However, the key challenging on evaluating 3D pore structure of fibrous scaffolds for better understanding the capability of different structures for biological application is not well investigated. This article reports a fast, accurate, nondestructive, and comprehensive evaluation approach based on confocal laser scanning microscopy (CLSM) and three-dimensional image analysis to study the pore structure and porosity parameters of Nano/Microfibrous scaffolds. Also a new method of making the fiber fluorescent using quantum dots (QDs) was applied before 3D imaging. Fibrous scaffolds with different porosity parameters produced by electrospinning and their 3D-pore structure was evaluated by this approach and the results were compared to results of capillary flow porometry. The pore structural properties measured in this approach are in good agreement with that measured by the capillary flow porometry (with significant level 0.05). Furthermore, the introduced approach can measure the pore interconnectivity of the scaffold.