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https://www.readbyqxmd.com/read/28342821/correction-of-axial-deformity-during-lengthening-in-fibular-hypoplasia-hexapodal-versus-monorail-external-fixation
#1
Antoine Chalopin, Loïc Geffroy, Sébastien Pesenti, Antoine Hamel, Franck Launay
INTRODUCTION: Childhood fibular hypoplasia is a rare pathology which may or may not involve limb-length discrepancy and axial deformity in one or more dimensions. The objective of the present study was to compare the quality of the axial correction achieved in lengthening procedures by hexapodal versus monorail external fixators. The hypothesis was that the hexapodal fixator provides more precise correction. MATERIAL AND METHODS: A retrospective multicenter study included 52 children with fibular hypoplasia...
March 22, 2017: Orthopaedics & Traumatology, Surgery & Research: OTSR
https://www.readbyqxmd.com/read/28337138/motor-skill-learning-in-an-insect-inspired-neuro-computational-control-system
#2
Eleonora Arena, Paolo Arena, Roland Strauss, Luca Patané
In nature, insects show impressive adaptation and learning capabilities. The proposed computational model takes inspiration from specific structures of the insect brain: after proposing key hypotheses on the direct involvement of the mushroom bodies (MBs) and on their neural organization, we developed a new architecture for motor learning to be applied in insect-like walking robots. The proposed model is a nonlinear control system based on spiking neurons. MBs are modeled as a nonlinear recurrent spiking neural network (SNN) with novel characteristics, able to memorize time evolutions of key parameters of the neural motor controller, so that existing motor primitives can be improved...
2017: Frontiers in Neurorobotics
https://www.readbyqxmd.com/read/28316142/evolutionary-ecology-of-beta-lactam-gene-clusters-in-animals
#3
Wouter Suring, Karen Meusemann, Alexander Blanke, Janine Mariën, Tim Schol, Valeria Agamennone, Anna Faddeeva-Vakhrusheva, Matty P Berg, Bram Brouwer, Nico M van Straalen, Dick Roelofs
Beta-lactam biosynthesis was thought to occur only in fungi and bacteria, but we recently reported the presence of isopenicillin N synthase in a soil-dwelling animal, Folsomia candida. However, it has remained unclear whether this gene is part of a larger beta-lactam biosynthesis pathway and how widespread the occurrence of penicillin biosynthesis is among animals. Here, we analyzed the distribution of beta-lactam biosynthesis genes throughout the animal kingdom and identified a beta-lactam gene cluster in the genome of F...
March 18, 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28290669/coordination-controlled-one-dimensional-molecular-chains-in-hexapodal-adenine-silver-ultrathin-films
#4
R Kamal Saravanan, Prithwidip Saha, Viruthakasi Venkatesh, Thiruvancheril G Gopakumar, Sandeep Verma
Growth of a silver coordination polymer of a C3-symmetric hexaadenine ligand is studied on highly oriented pyrolytic graphite (HOPG), using high-resolution atomic force microscopy (AFM). This unusual ligand offers 6-fold multidentate coordination sites, and consequently, a multidimensional growth of coordination polymer is expected. Notably, each discrete hexapodal unit is bridged by two silver ions along one of the crystallographic directions, resulting in high interaction energy along this direction. When the polymer was deposited on an HOPG surface from a dilute solution, we observed abundant one-dimensional (1D) coordination polymer chains, with a minimum width of approximately 4...
March 14, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28273908/specialized-adaptations-for-springtail-predation-in-mesozoic-beetles
#5
Zi-Wei Yin, Chen-Yang Cai, Di-Ying Huang, Li-Zhen Li
Insects exhibit a variety of morphological specializations specific to particular behaviors, and these permit the reconstruction of palaeobiological traits. Despite the critical importance of predator-prey strategies in insect evolution, the appearance of particular aspects of predation are often difficult to determine from the fossil record of hexapods. Here we report the discovery of highly specialized, mid-Cretaceous ant-like stone beetles (Staphylinidae: Scydmaeninae) displaying morphological modifications unknown among living scydmaenids and associated with predation on springtails (Collembola), a widespread and abundant group of significantly greater geological age...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28267607/amalga-like-virus-infecting-antonospora-locustae-a-microsporidian-pathogen-of-grasshoppers-plus-related-viruses-associated-with-other-arthropods
#6
Jesse D Pyle, Patrick J Keeling, Max L Nibert
A previously reported Expressed Sequence Tag (EST) library from spores of microsporidian Antonospora locustae includes a number of clones with sequence similarities to plant amalgaviruses. Reexamining the sequence accessions from that library, we found additional such clones, contributing to a 3247-nt contig that approximates the length of an amalga-like virus genome. Using A. locustae spores stored from that previous study, and new ones obtained from the same source, we newly visualized the putative dsRNA genome of this virus and obtained amplicons yielding a 3387-nt complete genome sequence...
March 3, 2017: Virus Research
https://www.readbyqxmd.com/read/28254458/the-cortical-spatiotemporal-correlate-of-otolith-stimulation-vestibular-evoked-potentials-by-body-translations
#7
M Ertl, M Moser, R Boegle, J Conrad, P Zu Eulenburg, M Dieterich
The vestibular organ senses linear and rotational acceleration of the head during active and passive motion. These signals are necessary for bipedal locomotion, navigation, the coordination of eye and head movements in 3D space. The temporal dynamics of vestibular processing in cortical structures have hardly been studied in humans, let alone with natural stimulation. The aim was to investigate the cortical vestibular network related to natural otolith stimulation using a hexapod motion platform. We conducted two experiments, 1...
February 22, 2017: NeuroImage
https://www.readbyqxmd.com/read/28211509/climbing-favours-the-tripod-gait-over-alternative-faster-insect-gaits
#8
Pavan Ramdya, Robin Thandiackal, Raphael Cherney, Thibault Asselborn, Richard Benton, Auke Jan Ijspeert, Dario Floreano
To escape danger or catch prey, running vertebrates rely on dynamic gaits with minimal ground contact. By contrast, most insects use a tripod gait that maintains at least three legs on the ground at any given time. One prevailing hypothesis for this difference in fast locomotor strategies is that tripod locomotion allows insects to rapidly navigate three-dimensional terrain. To test this, we computationally discovered fast locomotor gaits for a model based on Drosophila melanogaster. Indeed, the tripod gait emerges to the exclusion of many other possible gaits when optimizing fast upward climbing with leg adhesion...
February 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28183867/propulsion-in-hexapod-locomotion-how-do-desert-ants-traverse-slopes
#9
Toni Wöhrl, Lars Reinhardt, Reinhard Blickhan
The employment of an alternating tripod gait to traverse uneven terrains is a common characteristic shared among many hexapoda. Since this could be one specific cause for their ecological success, we examined the alternating tripod gait of the desert ant Cataglyphis fortis together with their ground reaction forces and weight-specific leg impulses for level locomotion and on moderate (±30°) and steep (±60°) slopes in order to understand mechanical functions of individual legs during inclined locomotion...
February 9, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28157918/influence-of-axial-force-errors-on-the-deformation-of-the-4%C3%A2-%C3%A2-m-lightweight-mirror-and-its-correction
#10
Bin Lan, Xiaoxia Wu, Jianfeng Li, Ming Ming, Xiangyi Liu, Hongbo Yang
The lightweight primary mirror of the four meter Chinese telescope is supported axially by a passive hydraulic system, in parallel with an active system. The figure is sensitive to the errors in the axial forces, which can be effectively corrected using active optics. The squared RMS of this figure approximately follows the χ<sup>2</sup> distribution, as verified by Monte Carlo analysis. The probability distributions of the squared norm of the active-forces vector, of the squared norm of the leg-lengths vector in the hexapod platform, and of the squared RMS of the residual figure are discussed in terms of the bending modes obtained by singular-value decomposition of the influence matrix, the optical sensitivity matrix deduced through ray trace, and the Jacobian matrix of the hexapod platform...
January 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28148674/computer-hexapod-assisted-orthopaedic-surgery-provides-a-predictable-and-safe-method-of-femoral-deformity-correction
#11
A Hughes, N Heidari, S Mitchell, J Livingstone, M Jackson, R Atkins, F Monsell
AIMS: Computer hexapod assisted orthopaedic surgery (CHAOS), is a method to achieve the intra-operative correction of long bone deformities using a hexapod external fixator before definitive internal fixation with minimally invasive stabilisation techniques. The aims of this study were to determine the reliability of this method in a consecutive case series of patients undergoing femoral deformity correction, with a minimum six-month follow-up, to assess the complications and to define the ideal group of patients for whom this treatment is appropriate...
February 2017: Bone & Joint Journal
https://www.readbyqxmd.com/read/28110891/femoral-lengthening-in-children-and-adolescents
#12
REVIEW
Z Pejin
Current lengthening techniques are still based on the Ilizarov method and the concept of callotasis. Research and progress in medical devices have led to constant improvement in results. Hexapod fixators allow more precise correction of complex deformities, with shorter learning curve. Associating lengthening by external fixation (EF) to internal fixation (K-wire, intramedullary nail or locking plate) has reduced EF times and complications rates, while improving anatomic and functional results. Lengthening nails provides faster recovery of range of motion and return to activity during lengthening and consolidation, with better psychological tolerance...
January 16, 2017: Orthopaedics & Traumatology, Surgery & Research: OTSR
https://www.readbyqxmd.com/read/28046558/su-f-t-484-initial-evaluation-of-a-novel-6d-qa-phantom-hexacheck-for-daily-6d-couch-correction-assessment
#13
J E Roring, D Stanley, N Papanikolaou, A N Gutierrez
PURPOSE: Treatment couches with 6D correction capabilities have become a regular part of IGRT. While 6D couches have been shown to function mechanically well, phantoms for daily angular QA accuracy assessment have yet to be commercially available. Standard Imaging™ has developed a phantom designed for daily verification of pitch, roll, and yaw corrections. In this study, the mechanical integrity, reproducibility, and daily 6D correction stability of the phantom using both volumetric (Elekta- XVI kV-CBCT) and orthogonal kV (Brainlab ExacTrac) imaging was evaluated...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28028122/evolution-of-chemosensory-gene-families-in-arthropods-insight-from-the-first-inclusive-comparative-transcriptome-analysis-across-spider-appendages
#14
Joel Vizueta, Cristina Frías-López, Nuria Macías-Hernández, Miquel A Arnedo, Alejandro Sánchez-Gracia, Julio Rozas
Unlike hexapods and vertebrates, in chelicerates, knowledge of the specific molecules involved in chemoreception comes exclusively from the comparative analysis of genome sequences. Indeed, the genomes of mites, ticks and spiders contain several genes encoding homologs of some insect membrane receptors and small soluble chemosensory proteins. Here, we conducted for the first time a comprehensive comparative RNA-Seq analysis across different body structures of a chelicerate: the nocturnal wandering hunter spider Dysdera silvatica Schmidt 1981...
December 27, 2016: Genome Biology and Evolution
https://www.readbyqxmd.com/read/27989966/origin-and-evolution-of-the-panarthropod-head-a-palaeobiological-and-developmental-perspective
#15
Javier Ortega-Hernández, Ralf Janssen, Graham E Budd
The panarthropod head represents a complex body region that has evolved through the integration and functional specialization of the anterior appendage-bearing segments. Advances in the developmental biology of diverse extant organisms have led to a substantial clarity regarding the relationships of segmental homology between Onychophora (velvet worms), Tardigrada (water bears), and Euarthropoda (e.g. arachnids, myriapods, crustaceans, hexapods). The improved understanding of the segmental organization in panarthropods offers a novel perspective for interpreting the ubiquitous Cambrian fossil record of these successful animals...
December 18, 2016: Arthropod Structure & Development
https://www.readbyqxmd.com/read/27939714/the-rapidly-changing-landscape-of-insect-phylogenetics
#16
REVIEW
David R Maddison
Insect phylogenetics is being profoundly changed by many innovations. Although rapid developments in genomics have center stage, key progress has been made in phenomics, field and museum science, digital databases and pipelines, analytical tools, and the culture of science. The importance of these methodological and cultural changes to the pace of inference of the hexapod Tree of Life is discussed. The innovations have the potential, when synthesized and mobilized in ways as yet unforeseen, to shine light on the million or more clades in insects, and infer their composition with confidence...
December 2016: Current Opinion in Insect Science
https://www.readbyqxmd.com/read/27933259/deformity-correction-and-extremity-lengthening-in-the-lower-leg-comparison-of-clinical-outcomes-with-two-external-surgical-procedures
#17
Eugen Reitenbach, Robert Rödl, Georg Gosheger, Björn Vogt, Frank Schiedel
OBJECTIVE: Distraction osteogenesis is a method of stimulating the growth of new bone tissue in order to lengthen the extremities or bridge resected bone defects. In addition to the now-established intramedullary procedures, two different fixator systems are in use. The present study investigated the classical Ilizarov ring fixator (IRF) and a hexapod to assess the precision of lower-leg lengthening and complications classified using the Paley criteria for problems, obstacles, and complications...
2016: SpringerPlus
https://www.readbyqxmd.com/read/27914027/the-role-of-guided-growth-as-it-relates-to-limb-lengthening
#18
REVIEW
Peter M Stevens
For decades, the classic indication for limb lengthening has been reserved for anisomelia that was expected to reach or exceed 5 cm at maturity. Epiphysiodesis was reserved for discrepancies in the 2-5 cm range. With the increasing sophistication of fixators, including rail, hexapod, and hybrid, complex deformities may be corrected simultaneously while moderate to extreme lengthening is achieved. More recently, iterations of telescoping intramedullary rods have further strengthened our armamentarium. Meanwhile, permanent epiphysiodesis techniques, both open and percutaneous, have yielded to more versatile and reversible tethering of one (angle) or both (length) sides of a physis...
December 2016: Journal of Children's Orthopaedics
https://www.readbyqxmd.com/read/27896679/what-are-the-biomechanical-properties-of-the-taylor-spatial-frame%C3%A2
#19
Daniel J Henderson, Jeremy L Rushbrook, Paul J Harwood, Todd D Stewart
BACKGROUND: The Taylor Spatial Frame™ (TSF) is a versatile variant of the traditional Ilizarov circular fixator. Although in widespread use, little comparative data exist to quantify the biomechanical effect of substituting the tried-and-tested Ilizarov construct for the TSF hexapod system. QUESTIONS/PURPOSES: This study was designed to investigate the mechanical properties of the TSF system under physiologic loads, with and without the addition of a simulated bone model, with comparison to the standard Ilizarov frame...
November 28, 2016: Clinical Orthopaedics and related Research
https://www.readbyqxmd.com/read/27818969/surgical-treatment-of-neglected-clubfoot-using-external-fixator
#20
Rodrigo Mota Pacheco Fernandes, Maurilio Darcy Dos Santos Mendes, Renato Amorim, Marcus Aurélio Preti, Marcelo Back Sternick, Guilherme Pelosini Gaiarsa
The definition of neglected clubfoot (NC) includes a variable range of complex deformities of the foot that are refractory to conventional treatments or are treated inappropriately. Several etiologies may be related to this. The Ilizarov method has become established as a tool for treating these deformities. It minimizes soft-tissue damage through gradual correction of the deformity, with a high success rate in relation to achieving a plantigrade foot, with low incidence of recurrence. The indications for treatment include severe rigid deformities (Dimeglio III and IV), or adverse skin conditions...
September 2016: Revista Brasileira de Ortopedia
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