Artículos indexados
https://repository.uaeh.edu.mx/bitstream/123456789/11390
2024-03-29T01:48:28ZElectroacupuncture improves gait locomotion, H-reflex and ventral root potentials of spinal compression injured rats.
https://repository.uaeh.edu.mx/bitstream/123456789/17888
Electroacupuncture improves gait locomotion, H-reflex and ventral root potentials of spinal compression injured rats.
Rodríguez Torres, Erika Elizabeth
This study explored the effect of electroacupuncture stimulation (EA) on alterations in the Hoffman reflex
(H-reflex) response and gait locomotion provoked by spinal cord injury (SCI) in the rat. A compression
lesion of the spinal cord was evoked by insufflating a Fogarty balloon located in the epidural space at
the T8?9 spinal level of adult Wistar male rats (200?250 gr; n = 60). In different groups of SCI rats, EA
(frequencies: 2, 50 and 100 Hz) was applied simultaneously to Huantiao (GB30), Yinmen (BL37), Jizhong (GV6) and Zhiyang (GV9) acupoints from the third post-injury day until the experimental session. At 1,
2, 3 and 4 post-injury weeks, the BBB scores of the SCI group of rats treated with EA at 50 Hz showed a
gradual but greater enhancement of locomotor activity than the other groups of rats. Unrestrained gait
kinematic analysis of SCI rats treated with EA?50 Hz stimulation showed a significant improvement in
stride duration, length and speed (p < 0.05), whereas a discrete recovery of gait locomotion was observed
in the other groups of animals. After four post-injury weeks, the H-reflex amplitude and H-reflex/M
wave amplitude ratio obtained in SCI rats had a noticeable enhancement (217%) compared to sham rats
(n = 10). Meanwhile, SCI rats treated with EA at 50 Hz manifested a decreased facilitation of the H-reflex
amplitude and H/M amplitude ratio (154%) and a reduced frequency-dependent amplitude depression of
the H-reflex (66%). In addition, 50 Hz-EA treatment induced a recovery of the presynaptic depression of
the Gs-VRP evoked by PBSt conditioning stimulation in the SCI rat (63.2 ± 8.1%; n = 9). In concordance with
the latter, it could be suggested that 50 Hz-EA stimulation reduced the hyper-excitability of motoneurons
and provokes a partial improvement of the locomotive performance and H reflex responses by a possible
recovery of presynaptic mechanisms in the spinal cord of experimentally injured rats.
2017-01-01T00:00:00ZLuminescent polystyrene films, a novel way to reduce styrofoam residues
https://repository.uaeh.edu.mx/bitstream/123456789/16596
Luminescent polystyrene films, a novel way to reduce styrofoam residues
Zaleta Alejandre, Efraín
Polystyrene (PS) films doped with blue, yellow and red organic pigments have been deposited on glass and on commercial LED chips by spray pyrolysis using recycled PS as precursor, at deposition rates between 100 and 200 A/s. Doped films have roughness between 100 and 2500 A depending on the kind of pigment used; the surface morphology shows that the organic pigments incorporate into the polystyrene host forming globular particles of about 2 µm in diameter. The organic pigments used have luminescent emissions peaked at 440, 509 and 590 nm. The introduction of the proper combination of pigments on the PS film deposited on the LED chips renders a white light emission with (0.29, 0.37) and (0.30, 0.33) CIE (Commission international de l? eclairage) color coordinates. It was determined that the exposure to ´ violet light degrades the luminescent characteristics, however, blue light is not energetic enough to cause a degradation of the luminescent layer over similar period of time.
2015-01-01T00:00:00ZMathematical thinking, conceptual frameworks: a review of structures for analyzing problema- solving protocols
https://repository.uaeh.edu.mx/bitstream/123456789/11409
Mathematical thinking, conceptual frameworks: a review of structures for analyzing problema- solving protocols
Barrera Mora, Fernando
Recently, it has been considered important to reflect on the coincidences between the mathematical thinking of the School of Mathematics and the Discipline of Mathematics. It is widely accepted that a professional mathematician has naturally developed reasoning abilities that are essential to his practice. Such reasoning abilities are considered central to student learning at different educational levels. While the problem is not entirely new, the enrollment diminished in science and engineering university programs, suggests new reflections that might help the community when proposing scientific and engineering training programs. In this paper, we conduct an analysis of the processes developed by a mathematician during problem solving activities, with the aim of identifying relevant characteristics of the structure representations of mathematical concepts that he shows to solve problems. In the same lines, we pose the question: how this structure influences the mathematical creativity? [14]. The mathematics teacher, by knowing the characteristics of mathematical reasoning and the limitations to promoting them in the classroom, is better positioned to help his students in their learning processes.
2010-01-01T00:00:00ZMultichannel Detrended Fluctuation Analysis Reveals Synchronized Patterns of Spontaneous Spinal Activity in Anesthetized Cats
https://repository.uaeh.edu.mx/bitstream/123456789/11408
Multichannel Detrended Fluctuation Analysis Reveals Synchronized Patterns of Spontaneous Spinal Activity in Anesthetized Cats
Itzá Ortiz, Benjamín Alfonso
The analysis of the interaction and synchronization of relative large ensembles of neurons is fundamental for the understanding of complex functions of the nervous system. It is known that the temporal synchronization of neural ensembles is involved in the generation of specific motor, sensory or cognitive processes. Also, the intersegmental coherence of spinal spontaneous activity may indicate the existence of synaptic neural pathways between different pairs of lumbar segments. We present a multichannel detrended fluctuation analysis method (mDFA) to analyze the correlation dynamics of spontaneous spinal activity (SSA) from time series analysis. This method together with the classical detrended fluctuation analysis (DFA) were used to find out whether the SSA recorded in one or several segments in the spinal cord of the anesthetized cat occurs either in a random or in an organized manner. Our results are consistent with a non-random organization of the sets of neurons involved in the generation of spontaneous cord dorsum potentials (CDPs) recorded either from one lumbar segment or simultaneously from several lumbar segments. To test the sensitivity of the mDFA method we also examined the effects of small spinal lesions aimed to partially interrupt connectivity between neighboring lumbosacral segments. We found that the synchronization and correlation between the CDPs recorded from the L5 and L6 segments in both sides of the spinal cord were reduced when a lesion comprising the left dorsal quadrant was performed between the segments L5 and L6. The synchronization and correlation were reduced even further after a similar additional right spinal lesion. The mDFA method properly reveals the synchronization of multiple groups of neurons in several segments of the spinal cord. This method is envisaged as a useful tool to characterize the structure of higher order ensembles of cord dorsum spontaneous potentials after spinal cord or peripheral nerve lesions.
2011-01-01T00:00:00Z