31 research outputs found
Primary synovial chondromatosis: an elemental investigation of a rare skeletal pathology
Background: Primary synovial chondromatosis (PSC) is a rare idiopathic pathology characterized by the formation of osseocartilaginous nodules within synovial joints, tendons, or bursae. The mineralization pattern of PSC nodules is poorly understood and has yet to be investigated using elemental analysis. Mapping this pattern could elucidate the progression of the disease.
Materials and methods: PSC nodules discovered during dissection of a formalin fixed donor were analyzed. Scanning electron microscopy paired with energy dispersive X-ray spectroscopy (SEM-EDS) was used to quantify calcium and phosphorus levels to distinguish mineralized components from cartilage, indicated by increased carbon and oxygen concentrations.
Results: Nine nodules with average dimensions 1.76cm x 1.25cm were identified in the semimembranosus bursa. SEM-EDS demonstrated increased calcium phosphate levels in nodular cores, while outer margins contained primarily carbon and oxygen. Quantification of these elements revealed nodular peripheries to contain 68.0% carbon, 30.2% oxygen, 0.8% calcium, and 1.0% phosphate, while cores were comprised of 38.1% carbon, 42.1% oxygen, 14.1% calcium, and 5.7% phosphate.
Conclusions: Nodules were found to have mineralized cores embedded within a cartilaginous matrix. This pattern suggests disease progression is facilitated by endochondral ossification, opening the potential for new therapeutic techniques
New Family of Robust 2D Topological Insulators in van der Waals Heterostructures
We predict a new family of robust two-dimensional (2D) topological insulators
in van der Waals heterostructures comprising graphene and chalcogenides BiTeX
(X=Cl, Br and I). The layered structures of both constituent materials produce
a naturally smooth interface that is conducive to proximity induced new
topological states. First principles calculations reveal intrinsic
topologically nontrivial bulk energy gaps as large as 70-80 meV, which can be
further enhanced up to 120 meV by compression. The strong spin-orbit coupling
in BiTeX has a significant influence on the graphene Dirac states, resulting in
the topologically nontrivial band structure, which is confirmed by calculated
nontrivial Z2 index and an explicit demonstration of metallic edge states. Such
heterostructures offer an unique Dirac transport system that combines the 2D
Dirac states from graphene and 1D Dirac edge states from the topological
insulator, and it offers new ideas for innovative device designs
Spatio-Temporal Progression of Grey and White Matter Damage Following Contusion Injury in Rat Spinal Cord
Cellular mechanisms of secondary damage progression following spinal cord injury remain unclear. We have studied the extent of tissue damage from 15 min to 10 weeks after injury using morphological and biochemical estimates of lesion volume and surviving grey and white matter. This has been achieved by semi-quantitative immunocytochemical methods for a range of cellular markers, quantitative counts of white matter axonal profiles in semi-thin sections and semi-quantitative Western blot analysis, together with behavioural tests (BBB scores, ledged beam, random rung horizontal ladder and DigiGait™ analysis). We have developed a new computer-controlled electronic impactor based on a linear motor that allows specification of the precise nature, extent and timing of the impact. Initial (15 min) lesion volumes showed very low variance (1.92±0.23 mm3, mean±SD, n = 5). Although substantial tissue clearance continued for weeks after injury, loss of grey matter was rapid and complete by 24 hours, whereas loss of white matter extended up to one week. No change was found between one and 10 weeks after injury for almost all morphological and biochemical estimates of lesion size or behavioural methods. These results suggest that previously reported apparent ongoing injury progression is likely to be due, to a large extent, to clearance of tissue damaged by the primary impact rather than continuing cell death. The low variance of the impactor and the comprehensive assessment methods described in this paper provide an improved basis on which the effects of potential treatment regimes for spinal cord injury can be assessed
Van der Waals heterostructures
Research on graphene and other two-dimensional atomic crystals is intense and
likely to remain one of the hottest topics in condensed matter physics and
materials science for many years. Looking beyond this field, isolated atomic
planes can also be reassembled into designer heterostructures made layer by
layer in a precisely chosen sequence. The first - already remarkably complex -
such heterostructures (referred to as 'van der Waals') have recently been
fabricated and investigated revealing unusual properties and new phenomena.
Here we review this emerging research area and attempt to identify future
directions. With steady improvement in fabrication techniques, van der Waals
heterostructures promise a new gold rush, rather than a graphene aftershock
Impact of Copper Overpressure on the Synthesis of Hexagonal Boron Nitride Atomic Layers
Hexagonal
boron nitride (h-BN) atomic layers are synthesized on
polycrystalline copper foils via a novel chemical vapor deposition
(CVD) process that maintains a vapor-phase copper overpressure during
growth. Compared to h-BN films grown without a copper overpressure,
this process results in a >10Ă— reduction of 3-dimensional
BN
fullerene-like surface features, a reduction of carbon and oxygen
contamination of 65% and 62%, respectively, an increase in h-BN grain
size of >2Ă—, and an 89% increase in electrical breakdown strength
Sources of Increasing Returns and Regional Innovation in the UK
This empirical paper investigates the impact of different sources of increasing returns on firm innovative behaviour in different regions of the UK. Of the different sources of increasing returns, the impact of intermediation and the emergence of specialized markets on the probability of innovation is of particular interest to this analysis. The existing literature on regional development in the UK strongly suggests that the South East has many features that may characterize an economy growing with a greater division of labour. These are less evident in the Industrial Heartland region of northern England. Other influences on innovation such as the impact of regional public R&D and dynamic economies to scale due to learning within a firm are also considered. Cet article empirique cherche à examiner l'impact des sources différentes des rendements croissants sur l'innovation des entreprises situées dans diverses régions au Royaume-Uni. Parmi les différentes sources des rendements croissants, il s'avère que les conséquences de l'intermédiation et l'émergence des marchés spécialisés sur la probabilité de l'innovation sont à noter pour ce qui est de cette analyse. La documentation disponible au sujet du développement régional au Royaume-Uni laisse vivement supposer que le Sud-est montre beaucoup des traits qui caractérisent une économie qui croît avec une division du travail plus importante. Ces traits-là sont moins évidents dans le berceau industriel qui est le nord du pays. D'autres facteurs qui influent sur l'innovation, tels l'impact de la recherche-développement publique régionale et les économies d'échelles dynamiques dues à l'apprentissage intra-entreprise, sont aussi considérés. Dieser empirische Aufsatz untersucht die Auswirkung verschiedener Quellen wachsenden Profits dank innovativem Firmenverhalten in verschiedenen Regionen des Vereinigten Königreichs. Von den verschiedenen Quellen vermehrten Gewinns sind das Aufkommen spezialisierter Märkte und die Auswirkung der 'Intermediation' auf die Wahrscheinlichkeit der Innovation von besonderem Interesse fur diese Analyse. Die bereits vorliegende Literatur über regionale Entwicklung im UK legt es entschieden nahe, daß sich im Südosten des Landes vielerlei Anzeichen finden, die fur eine Wirtschaft mit stärkerer Arbeitsteilung charakteristisch sein könnten. In der Region des industriellen Kernlandes im Norden Englands sind sie weniger zu beobachten. Darüberhinaus werden auch andere Einflüsse auf Innovation in Betracht gezogen, wie die Auswirkung regionaler öffentlicher Forschung und Entwicklung, sowie dynamische Einsparungen durch erhöhte Produktion dank Wissenserwerb in einer Firma.Increasing Returns And Growth, Specialized Markets Public, R And D Innovation, By Firms, Regional Innovation, Regional Development,