Locomotion in stroke subjects: interactions between unaffected and affected sides

The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm muscles of both sides, with larger amplitudes prior to swing over an obstacle compared with normal swing. In post-stroke subjects, the electromyography responses were stronger on both sides when the tibial nerve of the unaffected leg was stimulated compared with stimulation of the affected leg. This difference was more pronounced when stimuli were applied prior to swing over an obstacle than prior to normal swing. This indicates an impaired processing of afferent input from the affected leg resulting in attenuated and little task-modulated reflex responses in the arm muscles on both sides. In contrast, an afferent volley from the unaffected leg resulted in larger electromyography responses, even in the muscles of the affected arm. Arm muscle activations were stronger during swing over an obstacle than during normal swing, with no difference in electromyography amplitudes between the unaffected and affected sides. It is concluded that the deficits of the affected arm are compensated for by influences from the unaffected side. These observations indicate strong mutual influences between unaffected and affected sides during locomotion of post-stroke subjects, which might be used to optimize rehabilitation approache

Organelle-specific isoenzymes of plant V-ATPase as revealed by in vivo-FRET analysis

Seidel T, Schnitzer D, Golldack D, Sauer M, Dietz K-J. Organelle-specific isoenzymes of plant V-ATPase as revealed by in vivo-FRET analysis. BMC Cell Biology. 2008;9(1): 28.BACKGROUND: The V-ATPase (VHA) is a protein complex of 13 different VHA-subunits. It functions as an ATP driven rotary-motor that electrogenically translocates H+ into endomembrane compartments. In Arabidopsis thaliana V-ATPase is encoded by 23 genes posing the question of specific versus redundant function of multigene encoded isoforms. RESULTS: The transmembrane topology and stoichiometry of the proteolipid VHA-c" as well as the stoichiometry of the membrane integral subunit VHA-e within the V-ATPase complex were investigated by in vivo fluorescence resonance energy transfer (FRET). VHA-c", VHA-e1 and VHA-e2, VHA-a, VHA-c3, truncated variants of VHA-c3 and a chimeric VHA-c/VHA-c" hybrid were fused to cyan (CFP) and yellow fluorescent protein (YFP), respectively. The constructs were employed for transfection experiments with Arabidopsis thaliana mesophyll protoplasts. Subcellular localization and FRET analysis by confocal laser scanning microscopy (CLSM) demonstrated that (i.) the N- and C-termini of VHA-c" are localised in the vacuolar lumen, (ii.) one copy of VHA-c" is present within the VHA-complex, and (iii.) VHA-c" is localised at the ER and associated Golgi bodies. (iv.) A similar localisation was observed for VHA-e2, whereas (v.) the subcellular localisation of VHA-e1 indicated the trans Golgi network (TGN)-specifity of this subunit. CONCLUSION: The plant proteolipid ring is a highly flexible protein subcomplex, tolerating the incorporation of truncated and hybrid proteolipid subunits, respectively. Whereas the membrane integral subunit VHA-e is present in two copies within the complex, the proteolipid subunit VHA-c" takes part in complex formation with only one copy. However, neither VHA-c" isoform 1 nor any of the two VHA-e isoforms were identified at the tonoplast. This suggest a function in endomembrane specific VHA-assembly or targeting rather than proton transport

Scenario-based mission statements; Promoting sustainable urban development in the context of the energy transition

Using a planning process for the Stuttgart Neckar Valley as a case study, this paper analyzes the urban inertial forces that counteract the transformation of energy infrastructure areas in the context of the energy transition. In order to overcome these forces, a scenario-based mission statement was developed in which spatial scenarios were derived from energy scenarios and finally summarized in a concept plan for the Neckar Valley. The mission statement was developed following an analytical-deliberative and transdisciplinary approach. The approach to mission statement development presented here can respond flexibly to changing framework conditions and thus serve as a model for other cities with large-scale energy infrastructures in transition.Am Beispiel eines Planungsprozesses für das Stuttgarter Neckartal wird analysiert, welche urbanen Beharrungskräfte einer städtebaulichen Transformation von Energieinfrastrukturflächen im Rahmen der Energiewende entgegenwirken. Um diese Kräfte zu überwinden wurde ein szenariobasiertes Leitbild entwickelt, in dem auf Basis energiewirtschaftlicher Szenarien räumliche Szenarien abgeleitet und schließlich in einem Konzeptplan für das Neckartal zusammengeführt wurden. Zur Entwicklung des Leitbilds wurde ein analytisch-deliberatives und transdisziplinäres Vorgehen verfolgt. Der vorgestellte Ansatz der Leitbildentwicklung kann flexibel auf sich verändernde Rahmenbedingungen reagieren und daher als Vorbild für andere Städte mit großmaßstäblichen Energieinfrastrukturen dienen, die sich im Rahmen der Energiewende verändern werden

Influence of trailing edge tab on moment characteristics of NACA 23012 airfoil

A comparison of predicted and measured aerodynamic characteristics of the original NACA 23012 airfoil and an airfoil with a trailing edge tab is presented. XFOIL code is used for prediction. It is shown that the modification of the airfoils only on the upper side at the trailing edge affects practically only moment characteristics. An example of the airfoil modification with zero moment coefficients is presented. First published online: 14 Oct 201

Structural basis for selective targeting of Rac subfamily GTPases by a bacterial effector protein

Ras-homology (Rho) family GTPases are conserved molecular switches controlling fundamental cellular activities in eukaryotic cells. As such, they are targeted by numerous bacterial toxins and effector proteins, which have been intensively investigated regarding their biochemical activities and discrete target spectra; however, molecular mechanisms of target selectivity have remained elusive. Here, we report a bacterial effector protein that targets all four Rac subfamily members of Rho family GTPases, but none of the closely related Cdc42 or RhoA subfamilies. This exquisite target selectivity of the FIC domain AMP-transferase Bep1 from Bartonella rochalimae is based on electrostatic interactions with a subfamily-specific pair of residues in the nucleotide-binding motif and the Rho insert helix. Residue substitutions at the identified positions in Cdc42 facilitate modification by Bep1, while corresponding Cdc42-like substitutions in Rac1 greatly diminish modification. Our study establishes a structural paradigm for target selectivity towards Rac subfamily GTPases and provides a highly selective tool for their functional analysis

Dose-response relationship of locomotor training in patients with spinal cord injury : preliminary results

Background: A large proportion of patients with spinal cord injury (SCI) regain ambulatory function. However, during the first 3 months most patients are unable to walk without support. To enable ambulatory training at such an early stage the body weight is partially relieved and leg movement assisted by two therapists. A more recent approach is the application of robotic-based assistance, which allows for longer training duration. From the science of motor learning and studies including patients with stroke, it is known that training effects depend on the duration of the training. Longer training results in a better walking function. Purpose: The aim of the present study is to evaluate whether prolonged robot-assisted walking training leads to a better walking outcome in patients with incomplete SCI, who are initially unable to walk independently (i.e. B and C according to the International Standards for Neurological Classification of SCI-ISNCSCI), and whether such training is feasible or is associated with undesirable effects. Methods: Patients from three sites with an acute incomplete SCI (within 60 days after injury) were randomized to either standard training (session duration 25 minutes) or intensive training (session duration 50 minutes). After 8 weeks of training walking ability (Walking Index for SCI-WISCI, scale 0-20: 0=not able to walk, 20= able to walk independently), the occurrence of adverse events and the rate of perceived exertion (RPE, scale 1-10: 1=very light, 10= very, very hard), as well as patients’ global impression of change (PGIC, scale 0 -10: 0= much better, 5= no change, 10= much worse) were compared between groups. Results: Seventeen patients with incomplete SCI were randomly assigned either to standard training (ISNCSCI B: n=6; C: n=2) or to intensive training (B: n=3; C: n=6). The average duration of training of the standard group was half the length of the intensive group (24.9±0.6 minutes vs. 48.3±3.2 minutes; p=0.01). Both groups performed an equal number of training sessions within 8 weeks (33.8±6.8 and 34.9±6.0; n.s.). The median WISCI changed from 0 to 4 in the standard group (n.s.) and from 0 to 10.5 (p<0.05) in the intensive group. However, the group difference after training did not reach statistical significance. The median RPE (standard: 6.5, range 1-10 and intensive: 6, range 1-10; n.s.) and the PGIC (standard: 3.5, range 0-5; intensive: 2.5, range 1-4; n.s.) did not differ between the standard and intensive training groups. Conclusions: Longer training using a robotic device is feasible and is not associated with undesirable effects in patients with incomplete SCI. Results show a trend towards a positive dose-response relationship. However, there was a larger proportion of patients with a motor incomplete SCI (i.e. ISNCSCI: C) in the intensive training group. Implications: The duration of a standard training session needs to be re-addressed. Results indicate that more intensive training leads to a better outcome

In vivo evidence of remote neural degeneration in the lumbar enlargement after cervical injury

OBJECTIVE To characterize remote secondary neurodegeneration of spinal tracts and neurons below a cervical spinal cord injury (SCI) and its relation to the severity of injury, the integrity of efferent and afferent pathways, and clinical impairment. METHODS A comprehensive high-resolution MRI protocol was acquired in 17 traumatic cervical SCI patients and 14 controls at 3T. At the cervical lesion, a sagittal T2-weighted scan provided information on the width of preserved midsagittal tissue bridges. In the lumbar enlargement, high-resolution T2*-weighted and diffusion-weighted scans were used to calculate tissue-specific cross-sectional areas and diffusion indices, respectively. Regression analyses determined associations between MRI readouts and the electrophysiologic and clinical measures. RESULTS At the cervical injury level, preserved midsagittal tissue bridges were present in the majority of patients. In the lumbar enlargement, neurodegeneration-in terms of macrostructural and microstructural MRI changes-was evident in the white matter and ventral and dorsal horns. Patients with thinner midsagittal tissue bridges had smaller ventral horn area, higher radial diffusivity in the gray matter, smaller motor evoked potential amplitude from the lower extremities, and lower motor score. In addition, smaller width of midsagittal tissue bridges was also associated with smaller tibialis sensory evoked potential amplitude and lower light-touch score. CONCLUSIONS This study shows extensive tissue-specific cord pathology in infralesional spinal networks following cervical SCI, its magnitude relating to lesion severity, electrophysiologic integrity, and clinical impairment of the lower extremity. The clinical eloquence of remote neurodegenerative changes speaks to the application of neuroimaging biomarkers in diagnostic workup and planning of clinical trials

Polyacrylonitrile-containing amphiphilic block copolymers: self-assembly and porous membrane formation

The development of hierarchically porous block copolymer (BCP) membranes via the application of the self-assembly and non-solvent induced phase separation (SNIPS) process is one important achievement in BCP science in the last decades. In this work, we present the synthesis of polyacrylonitrile-containing amphiphilic BCPs and their unique microphase separation capability, as well as their applicability for the SNIPS process leading to isoporous integral asymmetric membranes. Poly(styrene-co-acrylonitrile)-b-poly(2-hydroxyethyl methacrylate)s (PSAN-b-PHEMA) are synthesized via a two-step atom transfer radical polymerization (ATRP) procedure rendering PSAN copolymers and BCPs with overall molar masses of up to 82 kDa while maintaining low dispersity index values in the range of Đ = 1.13-1.25. The polymers are characterized using size-exclusion chromatography (SEC) and NMR spectroscopy. Self-assembly capabilities in the bulk state are examined using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) measurements. The fabrication of isoporous integral asymmetric membranes is investigated, and membranes are examined by scanning electron microscopy (SEM). The introduction of acrylonitrile moieties within the membrane matrix could improve the membranes’ mechanical properties, which was confirmed by nanomechanical analysis using atomic force microscopy (AFM)