Trans‐spinal direct current stimulation modifies spinal cord excitability through synaptic and axonal mechanisms

Abstract The spinal cord is extremely complex. Therefore, trans‐spinal direct current stimulation (tsDCS) is expected to produce a multitude of neurophysiological changes. Here, we asked how tsDCS differentially affects synaptic and nonsynaptic transmission. We investigated the effects of tsDCS on synaptically mediated responses by stimulating the medullary longitudinal fascicle and recording responses in the sciatic nerve and triceps and tibialis anterior muscles. Response amplitude was increased during cathodal‐tsDCS (c‐tsDCS), but reduced during anodal‐tsDCS (a‐tsDCS). After‐effects were dependent on the frequency of the test stimulation. c‐tsDCS‐reduced responses evoked by low‐frequency (0.5 Hz) test stimulation and increased responses evoked by high‐frequency (400 Hz) test stimulation. a‐tsDCS had opposite effects. During and after c‐tsDCS, excitability of the lateral funiculus tract (LFT) and dorsal root fibers was increased. However, a‐tsDCS caused a complex response, reducing the excitability of LFT and increasing dorsal root fiber responses. Local DC application on the sciatic nerve showed that the effects of DC on axonal excitability were dependent on polarity, duration of stimulation, temporal profile (during vs. after stimulation), orientation of the current direction relative to the axon and relative to the direction of action potential propagation, distance from the DC electrode, and the local environment of the nervous tissue. Collectively, these results indicate that synaptic as well as axonal mechanisms might play a role in tsDCS‐induced effects. Therefore, this study identified many factors that should be considered in interpreting results of DCS and in designing tsDCS‐based interventions

Modulation of gamma and alpha spinal motor neurons activity by trans-spinal direct current stimulation: effects on reflexive actions and locomotor activity

Spontaneous and evoked spinal activities interact to set the characteristics of emergent motor responses. Gamma motor neurons have feedforward and feedback functions in motor control, which are crucial for transforming motor commands into action. Meanwhile, the intrinsic excitability and functional connectivity of alpha motor neurons determine the accuracy of actions. In this study, we investigated the effects of trans-spinal direct current stimulation (tsDCS) on spontaneous and cortically evoked activity of well-isolated single units of gamma and alpha motor neurons in mice. We also investigated the effects of tsDCS on reflexive and locomotor actions. In general, motor neurons showed increased responses to cathodal tsDCS (c-tsDCS) and decreased responses to anodal tsDCS (a-tsDCS). These effects were observed for cortically evoked discharges and spontaneous firing rates of gamma motor neurons, cortically evoked discharges of larger alpha motor neurons, and spontaneous firing rates of smaller alpha motor neurons. An exception was that spontaneous firing rates of larger alpha motor neurons showed the opposite pattern of reduction by c-tsDCS and increase by a-tsDCS. Reflexive and voluntary behavior were also increased by c-tsDCS and reduced by a-tsDCS. Specifically, the amplitude and duration of crossed and tail pinch reflexes in decerebrate animals and the quality of ground and treadmill walking patterns in healthy awake animals showed this pattern. These polarity-specific changes in behavior could be attributed to polarity-mediated modulation of alpha and gamma motor neuron activity and spinal circuitry. The results reveal an important principle: effects of tsDCS on spinal motor neurons depend on current polarity and cell size

Las notas a pie de página en la traducción del Corán

Podríamos decir que entre el traductor y el autor del texto original hay un pacto implícito que garantiza que las opiniones personales del autor, por mucho que sean contrarias o semejantes a las del traductor, serán traducidas sin añadir ni quitar nada. No obstante, las traducciones del Corán están normalmente salpicadas de notas a pie de página a través de las cuales el traductor expresa su rechazo o agrado con el pensamiento que traduce, rompiendo así aquel pacto. La variedad y cantidad de las notas que ofrecen los traductores del Corán hacen de este Libro un ejemplo ideal para estudiar la presencia de notas en las obras traducidas.G.I. HUM 767 (ayudas a Grupos de Investigación de la Junta de Andalucía) / Editorial Comares (colección interlingua

Adquisición de la competencia traductológica: propuesta de una unidad didáctica de traducción general

This study proposes a teaching unit for direct translation from Spanish language into Arabic of nonspecialist texts. As a model of this sort of texts we have chosen two spanish cartoons. The unit that we propose is based on the Task based Approach. We are explaining some activities which are based on the usage of authentic texts, due to develop the contents of the teaching unit. This aims to improve the translatological competence of the students. We have chosen the Task-based Approach because we believe that is more adapted to the real needs of translation students than traditional teaching methods.Dans cette étude, nous proposons une unicité didactique à propos de la traduction directe de l'espagnol vers l'arabe pour les textes non spécialisés. Nous avons choisi deux dessinées en espagnol comme un modèle de ce genre de textes. L'unicité didactique que nous proposons se base sur l'approche par tâches, car nous expliquons quelques unes d'activités qui reposent sur l'exploitation de vrais textes pour évoluer les contenus de cette unicité didactique en vue d'améliorer la compétence traductologique chez les étudiants. Nous avons choisi l'approche par tâches parce que nous pensons qu'il s'accommode plus que les méthodes d'enseignement traditionnelles avec les vrais besoins qui ont les étudiants travaillant sur la traduction

WIMAX 802.16 PHYSICAL LAYER IMPLEMENTATION AND WIMAX COVERAGE AND PLANNING.

Over the last decade, the impact of wireless communication on the way we live and carry out business has been surpassed only by impact of the internet. But wireless communications is still in its infancy and the next stage of its development will be supplementing or replacing network infrastructure that was traditionally wired. The advent and adoption of the computer and the myriad software packages available for it offered the ability to generate a new wave of communication combining art, pictures, music and words into a targeted multimedia presentation. These presentations are large so that is requires higher bandwidth transmission facilities. Coupling this with the need for mobility, the solution would be wireless data delivery putting in consideration the bandwidth request. WiMAX technology is based on the IEEE 802.16 standard, it was only recently when the first IEEE 802.16 based equipment broadband began to enter the market. The additional spectrum, bandwidth and throughout capabilities of 802.16 will remarkably improve wireless data delivery and should allows even more wireless data service areas to be deployed economically. In this Final Year Project, a study about the IEEE 802.16 standard and mainly concentrate on the 802.16 PHY Layer behaviors was performed. A Simulink based model for the 802.16 PHY Layer was built for simulation and performance evaluation of WiMAX. MATLA

Excitability changes in the sciatic nerve and triceps surae muscle after spinal cord injury in mice

<p>Abstract</p> <p>Background</p> <p>From the onset to the chronic phase of spinal cord injury (SCI), peripheral axons and muscles are subjected to abnormal states of activity. This starts with very intense spasms during the first instant of SCI, through a no activity flaccidity phase, to a chronic hyperactivity phase. It remains unclear how the nature of this sequence may affect the peripheral axons and muscles.</p> <p>Methods</p> <p>We set out to investigate the changes in excitability of the sciatic nerve and to characterize the properties of muscle contractility after contusive injury of the mouse thoracic spinal cord.</p> <p>Results</p> <p>The following changes were observed in animals after SCI: 1) The sciatic nerve compound action potential was of higher amplitudes and lower threshold, with the longer strength-duration time constant and faster conduction velocity; 2) The latency of the onset of muscle contraction of the triceps surae muscle was significantly shorter in animals with SCI; 3) The muscle twitches expressed slower rising and falling slopes, which were accompanied by prolonged contraction duration in SCI animals compared to controls.</p> <p>Conclusion</p> <p>These findings suggest that in peripheral nerves SCI promotes hyperexcitability, which might contribute to mechanisms of spastic syndrome.</p

Satisfactory Short‑Term Outcomes of Condylar‑Constrained Knee Implants in Primary Total Knee Arthroplasty

Background: This research set out to assess the functional prognosis of constrained condylar knee (CCK) in patients with severe intraoperative instability and/or coronal deformity undergoing primary total knee arthroplasty (TKA). Materials and methods: A prospective cohort study including 25 knees (21 cases) who underwent primary TKA using CCK implants. Senior surgeon operated all patients during 2020/2021 and followed clinically and radiographically at three, six and 12 months and 2 years postoperative. All cases were implanted with a single-design, second-generation CCK implant with a mean follow-up of 2 years. Results: The current research involved 25 knees (21 patients) with mean age 62.8 ± 12.2 years and most of the included patients were females (19; 76%). Preoperatively, valgus was demonstrated in six patients (24%) while varus was reported in 19 patients (76%) with mean preoperative Valgus/Varus angle&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 24.4 ± 9.9. Mean preoperative Knee Society Score (KSS) was 13.2 ± 2.7, mean preoperative functional KSS was 23.8 ± 19.2 and mean preoperative range of movement (ROM) was 107 ± 19.2. After 6 months, mean values of KSS was 86.2 ± 7.59. After 1 year, 2 years &amp; over 2 years, mean values of KSS were 86.2 ± 7.6, 86.2 ± 7.5, 86.3 ± 7.7 respectively. Degree of change in KSS before and after the operation was 69.1 ± 20.9. Mean values of late functional KSS was 62.5 ± 23.3.&nbsp; Degree of change in functional KSS before and after the operation was 36.8 ± 19.1. Postoperative ROM mean value was 120 ± 6.9 with degree of change 12.8 ± 6.3. Three cases reported postoperative complications; one cellulitis, one anterior femoral notching and one peroneal nerve injury. KSS increased from baseline to early postoperative with statistically significant variances (p&lt; 0.001) however, no statistically significant changes were discovered in KSS from early postoperatively to 2 years of follow up. Conclusion: Primary TKA utilizing CCK implants in cases with severe coronal abnormalities and/or intraoperative instability had a good short-term survival rate, on par with less limited implants. With positive clinical and radiological results, CCK implants can be thought of as a good alternative in some instances. It is important to exercise caution while utilizing an elevated level of restraint, since less restricted implants should be preferred

Endovascular coiling versus surgical clipping in the treatment of ruptured anterior communicating artery aneurysm in Cairo University Hospitals

AbstractIntroductionAneurysmal Subarachnoid Hemorrhage (SAH) remains a devastating and often fatal form of stroke. The aneurysm is targeted for obliteration to prevent re-bleeding and to manage the possible complications from the event. Endovascular coiling has emerged as a less invasive alternative to conventional surgical clipping to treat aneurysms.Patients and methodsThis study was done prospectively in the Cairo University (Kasr El-Eini) hospitals to evaluate the outcome of both modalities used in the treatment of ruptured anterior communicating artery (Acom) aneurysm. 30 patients with Hunt and Hess grade I, II or III. were classified into two groups of microsurgical clipping (Endoscopic assistance used in five cases) and endovascular coiling.ResultsMortality rate was higher in the clipping group (26.7%) compared to the coiling group while recurrence rate was high in the coiling group (26.7%). Complications including hydrocephalus, hemiparesis and failed procedures occurred in (6.7%).ConclusionWe concluded that coiling is better for treating cases of ruptured Acom aneurysms being less invasive and achieving a favorable outcome compared to surgery. While Endoscope-Assisted Microsurgical Clipping (EAM) gives better control during clipping provided that a well-trained, competent and experienced neurosurgeon is available

Direct Current-Induced Calcium Trafficking in Different Neuronal Preparations

The influence of direct current (DC) stimulation on radioactive calcium trafficking in sciatic nerve in vivo and in vitro, spinal cord, and synaptosomes was investigated. The exposure to DC enhanced calcium redistribution in all of these preparations. The effect was dependent on the strength of the stimulation and extended beyond the phase of exposure to DC. The DC-induced increase in calcium sequestration by synaptosomes was significantly reduced by cobalt and rupture of synaptosomes by osmotic shock. Although both anodal and cathodal currents were effective, the experiments with two electrodes of different areas revealed that cathodal stimulation exerted stronger effect. The exposure to DC induced not only relocation but also redistribution of calcium within segments of the sciatic nerve. Enzymatic removal of sialic acid by preincubation of synaptosomes with neuroaminidase, or carrying out the experiments in sodium-free environment, amplified DC-induced calcium accumulation