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61.
62.
Ming‐Dong Zhang Amit Zeisel André Calas Marc Landry Matthew Fuszard Sally L Shirran Robert Schnell Árpád Dobolyi Márk Oláh Lauren Spence Jan Mulder Henrik Martens Miklós Palkovits Mathias Uhlen Harald H Sitte Catherine H Botting Ludwig Wagner Sten Linnarsson Tibor Harkany 《The EMBO journal》2015,34(1):36-54
63.
Sponberg S Spence AJ Mullens CH Full RJ 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2011,366(1570):1592-1605
A neuromechanical approach to control requires understanding how mechanics alters the potential of neural feedback to control body dynamics. Here, we rewrite activation of individual motor units of a behaving animal to mimic the effects of neural feedback without concomitant changes in other muscles. We target a putative control muscle in the cockroach, Blaberus discoidalis (L.), and simultaneously capture limb and body dynamics through high-speed videography and a micro-accelerometer backpack. We test four neuromechanical control hypotheses. We supported the hypothesis that mechanics linearly translates neural feedback into accelerations and rotations during static postural control. However, during running, the same neural feedback produced a nonlinear acceleration control potential restricted to the vertical plane. Using this, we reject the hypothesis from previous work that this muscle acts primarily to absorb energy from the body. The conversion of the control potential is paralleled by nonlinear changes in limb kinematics, supporting the hypothesis that significant mechanical feedback filters the graded neural feedback for running control. Finally, we insert the same neural feedback signal but at different phases in the dynamics. In this context, mechanical feedback enables turning by changing the timing and direction of the accelerations produced by the graded neural feedback. 相似文献
64.
Arends S Brouwer E van der Veer E Groen H Leijsma MK Houtman PM Th A Jansen TL Kallenberg CG Spoorenberg A 《Arthritis research & therapy》2011,13(3):R94
Introduction
Identifying ankylosing spondylitis (AS) patients who are likely to benefit from tumor necrosis factor-alpha (TNF-α) blocking therapy is important, especially in view of the costs and potential side effects of these agents. Recently, the AS Disease Activity Score (ASDAS) has been developed to assess both subjective and objective aspects of AS disease activity. However, data about the predictive value of the ASDAS with respect to clinical response to TNF-α blocking therapy are lacking. The aim of the present study was to identify baseline predictors of response and discontinuation of TNF-α blocking therapy in AS patients in daily clinical practice. 相似文献65.
de Groot L Hinkema H Westra J Smit AJ Kallenberg CG Bijl M Posthumus MD 《Arthritis research & therapy》2011,13(6):R205
Introduction
Advanced glycation end products (AGEs) are produced and can accumulate during chronic inflammation, as might be present in patients with rheumatoid arthritis (RA). AGEs are involved in the development of cardiovascular disease. The aim of this study is to evaluate whether AGEs are increased in patients with long-standing RA and whether AGE accumulation is related to disease activity, disease severity and measures of (premature) atherosclerosis, such as endothelial activation, endothelial dysfunction and intima media thickness (IMT). 相似文献66.
Gliding has evolved independently at least six times in mammals. Multiple hypotheses have been proposed to explain the evolution of gliding. These include the evasion of predators, economical locomotion or foraging, control of landing forces, and habitat structure. Here we use a combination of comparative methods and ecological and biomechanical data collected from free-ranging animals to evaluate these hypotheses. Our comparative data suggest that the origins of gliding are often associated with shifts to low-quality diets including leaves and plant exudates. Further, data from free-ranging colugos suggest that although gliding is not more energetically economical than moving through the canopy, it is much faster, allowing shorter times of transit between foraging patches and therefore more time available to forage in a given patch. In addition to moving quickly, gliding mammals spend only a small fraction of their overall time engaged in locomotion, likely offsetting its high cost. Kinetic data for both take-off and landing suggest that selection on these behaviors could also have shaped the evolution of gliding. Glides are initiated by high-velocity leaps that are potentially effective in evading arboreal predators. Further, upon landing, the ability to control aerodynamic forces and reduce velocity prior to impact is likely key to extending distances of leaps or glides while reducing the likelihood of injury. It is unlikely that any one of these hypotheses exclusively explains the evolution of gliding, but by examining gliding in multiple groups of extant animals in ecological and biomechanical contexts, new insights into the evolution of gliding can be gained. 相似文献
67.
A study spanning ten years revealed changes in wing-morph ratios corroborating the hypothesis that the wing-dimorphic introduced carabid, Pterostichus melanarius Ill.,is spreading through flight, from the city of Edmonton, Canada and establishing populations in natural aspen forest of more rural areas 45-50 km to the East. Comparison of wing-morph ratios between Pterostichus melanarius and the native wing dimorphic species Agonum retractum LeConte suggests that the spatial variation in ratios for Pterostichus melanarius does not reflect underlying environmental variation, but instead the action of selective forces on this wing-dimorphic species. About ten years after its earliest detection in some rural sites the frequency of macropterous individuals in Pterostichus melanarius has decreased c. five-fold, but it is still above the level seen in European populations in which the two wing-morphs are thought to exist in equilibrium. Pterostichus melanarius is expanding its range in native aspen forest much faster than three other introduced species Clivina fossor L.), Carabus granulatus O.F. Müllerand Clivina fossor L also encountered in this study. The two Carabus species are flightless, but Carabus fossor can be dimorphic. Although these four non-native ground beetle species comprise >85% of the carabids collected at sites in urban Edmonton, activity-density of native carabids was similar across the urban-rural gradient, suggesting little direct impact of introduced species on the local abundance of native species. In a second study conducted at a smaller scale near George Lake, Alberta, macropterous individuals of Pterostichus melanarius have penetrated furthest and most rapidly into native aspen forest. Furthermore, the percentage of micropterous individuals has increased markedly in areas first colonized a decade previously. Overall, these studies support the idea that macropterous beetles in wing-d dimorphic species are important vanguards for early colonization of unexploited territory, but that flightless individuals replace the flying morph relatively rapidly once populations are established. 相似文献
68.
Background
A recent study on expression and function of the ortholog of the Drosophila collier (col) gene in various arthropods including insects, crustaceans and chelicerates suggested a de novo function of col in the development of the appendage-less intercalary segment of insects. However, this assumption was made on the background of the now widely-accepted Pancrustacea hypothesis that hexapods represent an in-group of the crustaceans. It was therefore assumed that the expression of col in myriapods would reflect the ancestral state like in crustaceans and chelicerates, i.e. absence from the premandibular/intercalary segment and hence no function in its formation. 相似文献69.
70.
Bryan SJ Burroughs NJ Evered C Sacharz J Nenninger A Mullineaux CW Spence EM 《PloS one》2011,6(5):e19625