SURFACE MODIFICATION OF TPR SOLE: AN APPROACH TO IMPROVE SLIP RESISTANCE ON QUARRY AND CERAMIC TILES

Human slip on smooth surfaces is a common accident, even though the footwear soling materials are designed with cleats and treads to provide more friction with the floor. About 20% of footwear is made with thermoplastic rubber (TPR; styrene-butadiene-styrene) soles. The slip resistance property under wet-flooring conditions of this kind of sole is poor because of the nonionic nature of the polymer. Chemical surface modification can be exploited to improve the slip-resistance property of TPR soles. The surface is chemically modified with trichloroisocyanuric acid in a methyl ethyl ketone medium (TCI/MEK; at 1, 2, and 3%) to introduce chlorinated and oxidized moieties to the rubber surface. The extent of surface modification produced in TPR with this change can be tested using attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy, and contact angle and surface roughness measurements. The improvement in slip resistance can be evaluated by measuring the coefficient of friction using a dynamic slip-resistance tester. The extent of the change in the functional physical properties, such as surface roughness, contact angle, work adhesion, in slip resistance can be improved by optimizing the concentration of trichloroisocyanuric acid. Physicomechanical properties of unmodified and modified soles that are essential for wear performance can be tested and compared. Quantitative changes on the surface of modified rubber soles increases surface roughness, reduces contact angles, and increases work energy, so there is a considerable increase in the coefficient of friction, especially under wet floor conditions. The chemical surface treatment tends to reduce the bulk mechanical properties, such as tensile strength, elongation at break, and abrasion resistance, because cyanuric acid attacks the sole. The coefficient of friction produces a positive trend at 1 and 2% TCI/MEK treatments, but the trend is negative at a 3% concentration. The optimum surface treatment level for surface modification to enhance the slip resistance of TPR is 2% TCI/MEK.

Targeting the motor end plates in the mouse hindlimb gives access to a greater number of spinal cord motor neurons: an approach to maximize retrograde transport

Lower motor neuron dysfunction is one of the most debilitating neurological conditions and, as such, significantly impacts on the quality of life of affected individuals. Within the last decade, the engineering of mouse models of lower motor neuron diseases has facilitated the development of new therapeutic scenarios aimed at delaying or reversing the progression of these conditions. In this context, motor end plates (MEPs) are highly specialized regions on the skeletal musculature that offer minimally invasive access to the pre-synaptic nerve terminals, henceforth to the spinal cord motor neurons. Transgenic technologies can take advantage of the relationship between the MEP regions on the skeletal muscles and the corresponding motor neurons to shuttle therapeutic genes into specific compartments within the ventral horn of the spinal cord. The first aim of this neuroanatomical investigation was to map the details of the organization of the MEP zones for the main muscles of the mouse hindlimb. The hindlimb was selected for the present work, as it is currently a common target to challenge the efficacy of therapies aimed at alleviating neuromuscular dysfunction. This MEP map was then used to guide series of intramuscular injections of Fluoro-Gold (FG) along the muscles' MEP zones, therefore revealing the distribution of the motor neurons that supply them. Targeting the entire MEP regions with FG increased the somatic availability of the retrograde tracer and, consequently, gave rise to FG-positive motor neurons that are organized into rostro-caudal columns spanning more spinal cord segments than previously reported. The results of this investigation will have positive implications for future studies involving the somatic delivery and retrograde transport of therapeutic transgenes into affected motor neurons. These data will also provide a framework for transgenic technologies aiming at maintaining the integrity of the neuromuscular junction for the treatment of lower motor neuron dysfunctions.