1,318 research outputs found
Through the looking-glass:Mirror feedback modulates temporal and spatial aspects of bimanual coordination
Mirror therapy has become an effective and recommended intervention for a range of conditions affecting the upper limb (e.g. hemiparesis following stroke). However, little is known about how mirror feedback affects the control of bimanual movements (as performed during mirror therapy). In this study, in preparation for future clinical investigations, we examined the kinematics of bimanual circle drawing in unimpaired participants both with (Experiment 1) and without (Experiment 2) a visual template to guide movement. In both experiments, 15 unimpaired right-handed participants performed self-paced continuous bimanual circle-drawing movements with a mirror/symmetrical coordination pattern. For the mirror condition, vision was directed towards the mirror in order to monitor the reflected limb. In the no mirror condition, the direction of vision was unchanged, but the mirror was replaced with an opaque screen. Movements of both hands were recorded using motion capture apparatus. In both experiments, the most striking feature of movements was that the hand behind the mirror drifted spatially during the course of individual trials. Participants appeared to be largely unaware of this marked positional change of their unseen hand, which was most pronounced when a template to guide movement was visible (Experiment 1). Temporal asynchrony between the limbs was also affected by mirror feedback in both experiments; in the mirror condition, illusory vision of the unseen hand led to a relative phase lead for that limb. Our data highlight the remarkable impact that the introduction of a simple mirror can have on bimanual coordination. Modulation of spatial and temporal features is consistent with the mirror inducing a rapid and powerful visual illusion, the latter appearing to override proprioceptive signals.</p
Real-time feedback to reduce low-back load in lifting and lowering
Low-back pain (LBP) is a common health problem. Literature indicates an exposure-response relation between work-related lifting and LBP. Therefore, this study investigated effects of three kinds of real-time feedback on low-back load, quantified as lumbar moments, during lifting. We recruited 97 healthy male and female participants without a recent history of LBP and without prior biomechanical knowledge on lifting. Participants were assigned to groups based on the time of enrollment, filling the four groups in the following order: moment feedback, trunk inclination angle feedback, lumbar flexion feedback, and a control group not receiving feedback. Feedback was given by a sound when a threshold level of the input variable was exceeded. Participants were unaware of the input variable for the feedback, but were instructed to try to avoid the audio feedback by changing their lifting strategy. The groups with feedback were able to reduce the audio feedback and thus changed the input variable towards a more desired level. Lumbar moments significantly decreased over trials in the inclination and moment feedback groups, remained similar in the lumbar flexion group and increased in the control group. Between group comparisons revealed that low-back load was significantly lower in the moment and inclination groups compared to the control group. Additionally, moments were lower in the inclination group than in the lumbar flexion group. Real-time feedback on moments or trunk inclination is a promising tool to reduce low-back load during lifting and lowering
Surface expression of a T cell receptor beta (TCR-beta) chain in the absence of TCR-alpha, -delta, and -gamma proteins
Regarding: ‘Explorative study to identify novel candidate genes related to oxaliplatin efficacy and toxicity using a DNA repair array'
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Our gift to all of Us: GA(Y)AM: Preface
This special issue of AVANT is all about Cognitive Innovation. It is not about CogNovo, the interdisciplinary and international doctoral training programme that produced three different Off the Lip events. It is not about Off the Lip 2017, the novel symposium format we developed to collaboratively create a publication resulting in this special issue of AVANT. It is not about the seemingly heterogeneous collection of papers that follow this preface. Collaborative Approaches to Cognitive Innovation required something else, something we are starting to capture in the four GIFT principles. While this special issue is not solely about CogNovo, Off the Lip events, or the content of the following submissions, all these aforementioned elements were necessary to shape our current understanding of Cognitive Innovation, the very process which led to numerous publications, exhibitions, and events during the past three years. In a sense, all of our previous endeavours have culminated in this collection of 26 distinct pieces of work, yet we hope and believe that this special issue also marks a beginning. Let us explain. [...
Disruption of a putative mitochondrial oxaloacetate shuttle protein in Aspergillus carbonarius results in secretion of malic acid at the expense of citric acid production
FWN – Publicaties zonder aanstelling Universiteit Leide
Heteroleptic coordination environments in metal-mediated DNA G-quadruplexes
The presence of metal centers with often highly conserved coordination environments is crucial for roughly half of all proteins, having structural, regulatory, or enzymatic function. To understand and mimic the function of metallo-enzymes, bioinorganic chemists pursue the challenge of synthesizing model compounds with well-defined, often heteroleptic metal sites. Recently, we reported the design of tailored homoleptic coordination environments for various transition metal cations based on unimolecular DNA G-quadruplex structures, templating the regioselective positioning of imidazole ligandosides LI. Here, we expand this modular system to more complex, heteroleptic coordination environments by combining LI with a new benzoate ligandoside LB within the same oligonucleotide. The modifications still allow the correct folding of parallel tetramolecular and antiparallel unimolecular G-quadruplexes. Interestingly, the incorporation of LB results in strong destabilization expressed in lower thermal denaturation temperatures Tm. While no transition metal cations could be bound by G-quadruplexes containing only LB, heteroleptic derivatives containing both LI and LB were found to complex CuII, NiII, and ZnII. Especially in case of CuII we found strong stabilizations of up to ΔTm = +34°C. The here shown system represents an important step toward the design of more complex coordination environments inside DNA scaffolds, promising to culminate in the preparation of functional metallo-DNAzymes
UGT1A1*28 genotype and irinotecan dosage in patients with metastatic colorectal cancer: a Dutch Colorectal Cancer Group study
The aim of the study was to investigate the associations between UGT1A1*28 genotype and (1) response rates, (2) febrile neutropenia and (3) dose intensity in patients with metastatic colorectal cancer treated with irinotecan. UGT1A1*28 genotype was determined in 218 patients receiving irinotecan (either first-line therapy with capecitabine or second-line as monotherapy) for metastatic colorectal cancer. TA7 homozygotes receiving irinotecan combination therapy had a higher incidence of febrile neutropenia (18.2%) compared to the other genotypes (TA6/TA6 : 1.5%; TA6/TA7 : 6.5%, P=0.031). TA7 heterozygotes receiving irinotecan monotherapy also suffered more febrile neutropenia (19.4%) compared to TA6/TA6 genotype (2.2%; P=0.015). Response rates among genotypes were not different for both regimens: combination regimen, P=0.537; single-agent, P=0.595. TA7 homozygotes did not receive a lower median irinotecan dose, number of cycles (P-values ⩾0.25) or more frequent dose reductions compared to the other genotypes (P-values for trend; combination therapy: 0.62 and single-agent: 0.45). Reductions were mainly (>80%) owing to grade ⩾3 diarrhoea, not (febrile) neutropenia. TA7/TA7 patients have a higher incidence of febrile neutropenia upon irinotecan treatment, but were able to receive similar dose and number of cycles compared to other genotypes. Response rates were not significantly different
Virtual obstacle crossing:Reliability and differences in stroke survivors who prospectively experienced falls or no falls
Introduction Stroke survivors often fall during walking. To reduce fall risk, gait testing and training with avoidance of virtual obstacles is gaining popularity. However, it is unknown whether and how virtual obstacle crossing is associated with fall risk. Aim The present study assessed whether obstacle crossing characteristics are reliable and assessed differences in stroke survivors who prospectively experienced falls or no falls. Method We recruited twenty-nine community dwelling chronic stroke survivors. Participants crossed five virtual obstacles with increasing lengths. After a break, the test was repeated to assess test-retest reliability. For each obstacle length and trial, we determined; success rate, leading limb preference, pre and post obstacle distance, margins of stability, toe clearance, and crossing step length and speed. Subsequently, fall incidence was monitored using a fall calendar and monthly phone calls over a six-month period. Results Test-retest reliability was poor, but improved with increasing obstacle-length. Twelve participants reported at least one fall. No association of fall incidence with any of the obstacle crossing characteristics was found. Discussion Given the absence of height of the virtual obstacles, obstacle avoidance may have been relatively easy, allowing participants to cross obstacles in multiple ways, increasing variability of crossing characteristics and reducing the association with fall risk. Conclusion These finding cast some doubt on current protocols for testing and training of obstacle avoidance in stroke rehabilitation
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