120 research outputs found
The redshift and broad band spectral energy distribution of NRAO 150
Context. NRAO 150 is one of the brightest radio and mm AGN sources on the
northern sky. It has been revealed as an interesting source where to study
extreme relativistic jet phenomena. However, its cosmological distance has not
been reported so far, because of its optical faintness produced by strong
Galactic extinction.
Aims. Aiming at measuring the redshift of NRAO 150, and hence to start making
possible quantitative studies from the source.
Methods. We have conducted spectroscopic and photometric observations of the
source in the near-IR, as well as in the optical.
Results. All such observations have been successful in detecting the source.
The near-IR spectroscopic observations reveal strong H and H
emission lines from which the cosmological redshift of NRAO 150
() has been determined for the first time. We classify the
source as a flat-spectrum radio-loud quasar, for which we estimate a large
super-massive black-hole mass . After
extinction correction, the new near-IR and optical data have revealed a
high-luminosity continuum-emission excess in the optical (peaking at
\,\AA, rest frame) that we attribute to thermal emission from the
accretion disk for which we estimate a high accretion rate, \,% of the
Eddington limit.
Conclusions. Comparison of these source properties, and its broad-band
spectral-energy distribution, with those of Fermi blazars allow us to predict
that NRAO 150 is among the most powerful blazars, and hence a high luminosity
-although not detected yet- -ray emitter.Comment: 8 pages, 4 figure
Evolution of EEG motor rhythms after spinal cord injury: A longitudinal study
Spinal cord injury (SCI) does not only produce a lack of sensory and motor function caudal to the level of injury, but it also leads to a progressive brain reorganization. Chronic SCI patients attempting to move their affected limbs present a significant reduction of brain activation in the motor cortex, which has been linked to the deafferentation. The aim of this work is to study the evolution of the motor-related brain activity during the first months after SCI. Eighteen subacute SCI patients were recruited to participate in bi-weekly experimental sessions during at least two months. Their EEG was recorded to analyze the temporal evolution of the event-related desynchronization (ERD) over the motor cortex, both during motor attempt and motor imagery of their paralyzed hands. The results show that the a and ß ERD evolution after SCI is negatively correlated with the clinical progression of the patients during the first months after the injury. This work provides the first longitudinal study of the event-related desynchronization during the subacute phase of spinal cord injury. Furthermore, our findings reveal a strong association between the ERD changes and the clinical evolution of the patients. These results help to better understand the brain transformation after SCI, which is important to characterize the neuroplasticity mechanisms involved after this lesion and may lead to new strategies for rehabilitation and motor restoration of these patients
The self-regulatory German health care system between growing competition and state hierarchy
This article focuses on the changing role of the state in financing, providing and regulating health care services under the German health care system from 1970-2000. While a reduced role of the state can be observed in terms of financing, our analysis of service provision indicates inconsistent developments. Monetary resource flow analyses indicate a decrease in private service provision as a percentage of total health expenditure, but when analysing the development of health employment we see a growth in “private” health care personnel. The most important changes, however, have taken place in terms of regulation. Since the early 1990s, the traditionally self-regulatory German health care system has simultaneously faced growing competition and state hierarchy
The Carbonation of Wollastonite: A Model Reaction to Test Natural and Biomimetic Catalysts for Enhanced CO2 Sequestration
One of the most promising strategies for the safe and permanent disposal of anthropogenic
CO2 is its conversion into carbonate minerals via the carbonation of calcium and magnesium silicates.
However, the mechanism of such a reaction is not well constrained, and its slow kinetics is a
handicap for the implementation of silicate mineral carbonation as an effective method for CO2
capture and storage (CCS). Here, we studied the different steps of wollastonite (CaSiO3) carbonation
(silicate dissolution -> carbonate precipitation) as a model CCS system for the screening of natural
and biomimetic catalysts for this reaction. Tested catalysts included carbonic anhydrase (CA),
a natural enzyme that catalyzes the reversible hydration of CO2(aq), and biomimetic metal-organic
frameworks (MOFs). Our results show that dissolution is the rate-limiting step for wollastonite
carbonation. The overall reaction progresses anisotropically along different [hkl] directions via a
pseudomorphic interface-coupled dissolution–precipitation mechanism, leading to partial passivation
via secondary surface precipitation of amorphous silica and calcite, which in both cases is anisotropic
(i.e., (hkl)-specific). CA accelerates the final carbonate precipitation step but hinders the overall
carbonation of wollastonite. Remarkably, one of the tested Zr-based MOFs accelerates the dissolution
of the silicate. The use of MOFs for enhanced silicate dissolution alone or in combination with other
natural or biomimetic catalysts for accelerated carbonation could represent a potentially effective
strategy for enhanced mineral CCS.This research was funded by the Spanish Government (grants CGL2015-70642-R,
CGL2015-73103-EXP, CTQ2017-84692-R), EU FEDER funding, the University of Granada (“Unidad Científica de
Excelencia” UCE-PP2016-05) and the Junta de Andalucía (grant P11-RNM-7550 and Research Group RNM-179).
We thank the personnel of the Centro de Instrumentación Científica (CIC) of the University of Granada for their
help during TG-DSC, FESEM, -XRD, and ICP-OES analyses
Intramuscular EMG-driven musculoskeletal modelling: towards implanted muscle interfacing in spinal cord injury patients
OBJECTIVE: Surface EMG-driven modelling has been proposed as a means to control assistive devices by estimating joint torques. Implanted EMG sensors have several advantages over wearable sensors but provide a more localized information on muscle activity, which may impact torque estimates. Here, we tested and compared the use of surface and intramuscular EMG measurements for the estimation of required assistive joint torques using EMG driven modelling. METHODS: Four healthy subjects and three incomplete spinal cord injury (SCI) patients performed walking trials at varying speeds. Motion capture marker trajectories, surface and intramuscular EMG, and ground reaction forces were measured concurrently. Subject-specific musculoskeletal models were developed for all subjects, and inverse dynamics analysis was performed for all individual trials. EMG-driven modelling based joint torque estimates were obtained from surface and intramuscular EMG. RESULTS: The correlation between the experimental and predicted joint torques was similar when using intramuscular or surface EMG as input to the EMG-driven modelling estimator in both healthy individuals and patients. CONCLUSION: We have provided the first comparison of non-invasive and implanted EMG sensors as input signals for torque estimates in healthy individuals and SCI patients. SIGNIFICANCE: Implanted EMG sensors have the potential to be used as a reliable input for assistive exoskeleton joint torque actuation
Intramuscular EMG-Driven Musculoskeletal Modelling: Towards Implanted Muscle Interfacing in Spinal Cord Injury Patients
Objective: Surface EMG-driven modelling has been proposed as a means to control assistive devices by estimating joint torques. Implanted EMG sensors have several advantages over wearable sensors but provide a more localized information on muscle activity, which may impact torque estimates. Here, we tested and compared the use of surface and intramuscular EMG measurements for the estimation of required assistive joint torques using EMG driven modelling. Methods: Four healthy subjects and three incomplete spinal cord injury (SCI) patients performed walking trials at varying speeds. Motion capture marker trajectories, surface and intramuscular EMG, and ground reaction forces were measured concurrently. Subject-specific musculoskeletal models were developed for all subjects, and inverse dynamics analysis was performed for all individual trials. EMG-driven modelling based joint torque estimates were obtained from surface and intramuscular EMG. Results: The correlation between the experimental and predicted joint torques was similar when using intramuscular or surface EMG as input to the EMG-driven modelling estimator in both healthy individuals and patients. Conclusion: We have provided the first comparison of non-invasive and implanted EMG sensors as input signals for torque estimates in healthy individuals and SCI patients. Significance: Implanted EMG sensors have the potential to be used as a reliable input for assistive exoskeleton joint torque actuation.The authors would like to thank Enrique Pérez Rizo, Natalia Comino Suárez and María Isabel Sinovas Alonso for their assistance on the experimental and data acquisition procedure
A data-globe and immersive virtual reality environment for upper limb rehabilitation after spinal cord injury
While a number of virtual data-gloves have been used in stroke, there is little evidence about their use in spinal cord injury (SCI). A pilot clinical experience with nine SCI subjects was performed comparing two groups: one carried out a virtual rehabilitation training based on the use of a data glove, CyberTouch combined with traditional rehabilitation, during 30 minutes a day twice a week along two weeks; while the other made only conventional rehabilitation. Furthermore, two functional indexes were developed in order to assess the patient’s performance of the sessions: normalized trajectory lengths and repeatability. While differences between groups were not statistically significant, the data-glove group seemed to obtain better results in the muscle balance and functional parameters, and in the dexterity, coordination and fine grip tests. Related to the indexes that we implemented, normalized trajectory lengths and repeatability, every patient showed an improvement in at least one of the indexes, either along Y-axis trajectory or Z-axis trajectory. This study might be a step in investigating new ways of treatments and objective measures in order to obtain more accurate data about the patient’s evolution, allowing the clinicians to develop rehabilitation treatments, adapted to the abilities and needs of the patients
Conceptual design of a functional electrical stimulation cycling platform as a rehabilitation therapy for spinal cord injury or stroke
Stroke and spinal cord injuries (SCI) are leading causes of
disability worldwide, involving problems in mobility, balance
and coordination, among others. While aerobic exercise is
associated with a greater plasticity in the motor cortex of
healthy individuals, its effect on neuroplasticity after suffer-
ing a stroke or a SCI is still unknown. Besides, there is no
methodology to promote both cardiovascular and neuroplastic
recovery in patients suffering from neurological injuries. Up
to now, it has been demonstrated that physical exercise is
a therapeutic intervention in many rehabilitation programs
that, apart from providing clear benefits related to the phys-
ical conditioning, functionality, mood and cardiovascular
health, it could also promote neuroplasticity. The literature
suggests that stronger neuroplastic responses are elicited
in mid-to-high intensity training programs, but the lack of
homogeneity in the dose-response and the non-uniform eval-
uations of the neuroplasticity seem to be a limitation to gen-
eralise the obtained results. The combination of functional
electrical stimulation (FES) with the benefits of cardiovas-
cular exercise makes cycling assisted by FES a promising
approach to target both the aerobic capacity and the neu-
romotor function. The objective of this project is to prove
that aerobic exercise during personalized FES-cycling could
contribute to enhance the process of neuroplasticity, and to
maintain locomotor and cardiovascular function in patients
with stroke or spinal cord injury.This work is partially developed within the Research
Network FUSION “Red Tem´atica Sobre Fusi´on de Tec-
nolog´ıas Rob´oticas y Estimulaci´on El´ectrica Neuro-
muscular para Neurorrehabilitaci´on de Trastornos del
Movimiento”, grant by Agencia Estatal de Investigaci´on
(RED2022-134319-T)
Gait kinematic analysis in patients with a mild form of central cord syndrome
<p>Abstract</p> <p>Background</p> <p>Central cord syndrome (CCS) is considered the most common incomplete spinal cord injury (SCI). Independent ambulation was achieved in 87-97% in young patients with CCS but no gait analysis studies have been reported before in such pathology. The aim of this study was to analyze the gait characteristics of subjects with CCS and to compare the findings with a healthy age, sex and anthropomorphically matched control group (CG), walking both at a self-selected speed and at the same speed.</p> <p>Methods</p> <p>Twelve CCS patients and a CG of twenty subjects were analyzed. Kinematic data were obtained using a three-dimensional motion analysis system with two scanner units. The CG were asked to walk at two different speeds, at a self-selected speed and at a slower one, similar to the mean gait speed previously registered in the CCS patient group. Temporal, spatial variables and kinematic variables (maximum and minimum lower limb joint angles throughout the gait cycle in each plane, along with the gait cycle instants of occurrence and the joint range of motion - ROM) were compared between the two groups walking at similar speeds.</p> <p>Results</p> <p>The kinematic parameters were compared when both groups walked at a similar speed, given that there was a significant difference in the self-selected speeds (p < 0.05). Hip abduction and knee flexion at initial contact, as well as minimal knee flexion at stance, were larger in the CCS group (p < 0.05). However, the range of knee and ankle motion in the sagittal plane was greater in the CG group (p < 0.05). The maximal ankle plantar-flexion values in stance phase and at toe off were larger in the CG (p < 0.05).</p> <p>Conclusions</p> <p>The gait pattern of CCS patients showed a decrease of knee and ankle sagittal ROM during level walking and an increase in hip abduction to increase base of support. The findings of this study help to improve the understanding how CCS affects gait changes in the lower limbs.</p
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