Ethical thinking machines in surgery and the requirement for clinical leadership

No abstract available

Macro-Architectures in Spinal Cord Scaffold Implants Influence Regeneration

Abstract Biomaterial scaffold architecture has not been investigated as a tunable source of influence on spinal cord regeneration. This study compared regeneration in a transected spinal cord within various designed-macro-architecture scaffolds to determine if these architectures alone could enhance regeneration. Three-dimensional (3-D) designs were created and molds were built on a 3-D printer. Salt-leached porous poly(ε-caprolactone) was cast in five different macro-architectures: cylinder, tube, channel, open-path with core, and open-path without core. The two open-path designs were created in this experiment to compare different supportive aspects of architecture provided by scaffolds and their influence on regeneration. Rats received T8 transections and implanted scaffolds for 1 and 3 months. Overall morphology and orientation of sections were characterized by H&E, luxol fast blue, and cresyl violet staining. Borders between intact gray matter and non-regenerated defect were observed from GFAP immunolabeling. Nerve fibers and regenerating axons were identified with Tuj-1 immunolabeling. The open-path designs allowed extension of myelinated fibers along the length of the defect both exterior to and inside the scaffolds and maintained their original defect length up to 3 months. In contrast, the cylinder, tube, and channel implants had a doubling of defect length from secondary damage and large scar and cyst formation with no neural tissue bridging. The open-path scaffold architectures enhanced spinal cord regeneration compared to the three other designs without the use of biological factors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63279/1/neu.2007.0473.pd

Characterization and regulation of the expression of scyllatoxin (Leiurotoxin I) receptors in the human neuroblastoma cell line NB-OK 1

Abstract125I-[Tyr2]scyllatoxin allowed to label a single class of high-affinity receptors in membranes from the human neuroblastoma cell line NB-OK 1. The Kd of these receptors was 60 pM for scyllatoxin (Leiurotoxin I) and 20 pM for apamin and the Bmax was low (3.8 fmol/mg membrane protein). K+ increased toxin binding at low concentrations but exerted opposite effects at high concentrations. Ca2+, guanidinium and Na+ exerted only inhibitory effects on binding. Scyllatoxin binding sites were overexpressed 2.5-fold after a 24-h cell pretreatment with 2 mM butyrate. This effect was suppressed by cycloheximide

A gradient-augmented level set method with an optimally local, coherent advection scheme

The level set approach represents surfaces implicitly, and advects them by evolving a level set function, which is numerically defined on an Eulerian grid. Here we present an approach that augments the level set function values by gradient information, and evolves both quantities in a fully coupled fashion. This maintains the coherence between function values and derivatives, while exploiting the extra information carried by the derivatives. The method is of comparable quality to WENO schemes, but with optimally local stencils (performing updates in time by using information from only a single adjacent grid cell). In addition, structures smaller than the grid size can be located and tracked, and the extra derivative information can be employed to obtain simple and accurate approximations to the curvature. We analyze the accuracy and the stability of the new scheme, and perform benchmark tests.Comment: 28 pages, 14 figure

Toward standard practices for sharing computer code and programs in neuroscience

Computational techniques are central in many areas of neuroscience and are relatively easy to share. This paper describes why computer programs underlying scientific publications should be shared and lists simple steps for sharing. Together with ongoing efforts in data sharing, this should aid reproducibility of research.This article is based on discussions from a workshop to encourage sharing in neuroscience, held in Cambridge, UK, December 2014. It was financially supported and organized by the International Neuroinformatics Coordinating Facility (http://www.incf.org), with additional support from the Software Sustainability institute (http://www.software.ac.uk). M.H. was supported by funds from the German federal state of Saxony-Anhalt and the European Regional Development Fund (ERDF), Project: Center for Behavioral Brain Sciences

KA-BAND equipment assembly for multimedia satellite payloads

This paper describes new equipment generation developed in Alcatel Space Industries to meet recent multimedia needs for Ka-Band satellite payloads. These units are built as assemblies, and use building blocks packaged with new MCM technology

Généralisation du concept de filtrage adapté application au filtrage d'images ros d'états de surface de la mer

Les images ROS sont actuellement très exploitées pour étudier l'état de surface de la mer. Ces images sont très dégradées par deux types de bruit : un bruit de lignage et un bruit granulaire. Le but de l'étude présentée est de diminuer le volume des perturbations afin d'augmenter la lisibilité de ces images. Pour réaliser le traitement, nous considérons la houle comme une texture stochastique à bande relativement étroite dont les propriétés sont spatialement lentement variables. L'expérience montre qu'il est possible d'estimer la matrice de variance-covariance du signal utile ; il est aussi loisible d'estimer la matrice de variance-covariance des termes perturbateurs. L'idée exploitée dans un premier temps est celle du filtre adapté au signal stochastique en présence des perturbations. Les tests numériques montrent que les résultats relatifs à ce filtrage adapté ne sont pas entièrement satisfaisants. L'originalité de l'étude réside dans l'exploitation simultanée de fonctions adaptées à la fois au signal stochastique assimilé à une texture et à l'ensemble des perturbations