The lizard tail regenerates after autotomy or amputation. After horseradish peroxidase injections in the regenerate, motoneurons were retrogradely labeled only in the three spinal segments rostral to the amputation, whose spinal nerves are severed by tail loss. The changes in these motoneurons, compared to those of lizards with original intact tails, were investigated 5, 15, and 30 days after caudotomy and at 8 months in lizards with mature regenerates. Morphometric analysis of Nissl-stained motoneurons rostral to the amputation revealed marked hypertrophy, peaking at 15 days, when chromatolysis and nuclear eccentricity were also evident; motoneuron perikarya remained significantly larger than in controls after tail regeneration. The dUTP nick-end labeling (TUNEL) stain for apoptotic neurons did not reveal labeled cells in the spinal cord 5 and 15 days after caudotomy. Nitric oxide synthase (NOS) expression was studied with nicotinamide adenine-dinucleotide phosphate (NADPH)-diaphorase histochemistry and evaluated quantitatively with densitometry. A few caudal spinal motoneurons were lightly stained in lizards with intact tails. Induction of NADPH-diaphorase positivity was evident in the vast majority of these cells 5 days after caudotomy and was very marked at 15 and 30 days, during tail regrowth. These data were confirmed by neuronal NOS immunohistochemistry. After tail regeneration, histochemical positivity was markedly down-regulated in the tail spinal motoneurons but persisted in the majority of these cells. The findings show that in the lizard caudotomy elicits in axotomized caudal spinal motoneurons NOS induction associated with plasticity phenomena and in particular with vigorous regeneration of axons that innervate the regrowing tail.
The number of older people needing healthcare is a growing global phenomenon. The assistance in long-term care comprises a complex of medical, nursing, rehabilitation, and social assistance services. The cost is substantial, but technology can help reduce spending by ensuring efficient health services and improving the quality of life. Advances in artificial intelligence, wireless communication systems, and nanotechnology allow the creation of intelligent home care systems avoiding hospitalization with evident cost containment. They are capable of ensuring functions of recognition of activities, monitoring of vital functions, and tracking. However, it is essential to also have information on location in order to be able to promptly intervene in case of unforeseen events or assist people in carrying out activities in order to avoid incorrect behavior. In addition, the automatic detection of physical activities performed by human subjects is identified as human activity recognition (HAR). This work presents an overview of the positioning system as part of an integrated HAR system. Lastly, this study contains each technology’s concepts, features, accuracy, advantages, and limitations. With this work, we want to highlight the relationship between HAR and the indoor positioning system (IPS), which is poorly documented in the literature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.