210 research outputs found
Design and development of anisotropic laminate scaffolds of electrospun polycaprolactone for annulus fibrosus tissue engineering applications
In several cases, current therapies available to treat a large number of musculoskeletal system diseases are unsatisfactory as they provide only temporary or partial restoration of the damaged or degenerated site. In an attempt to maintain a high standard of life quality and minimise the economic losses due to the treatments of these frequently occurring ailments and subsequent lost working days, alternative therapies are being explored. Contrary to the current treatments, tissue engineering aims to regenerate the impaired tissue rather than repair and alleviate the symptoms; thus offering a definitive solution.
The annulus fibrosus (AF) of the intervertebral disc (IVD) is a musculoskeletal system component frequently subjected to degeneration and rupture, characterised by predominance of anisotropically arranged collagen fibres.
In the present thesis, electrospinning technology is used to fabricate polycaprolactone (PCL) scaffolds intended to replicate the anisotropic structure of the AF. [Continues.
Epidemiological, pathological and microbiological study of equine dental caries
Dental caries is caused by acidogenic oral micro-organisms which convert
fermentable carbohydrates to acids that damage the tooth by causing a
demineralisation and disintegration of the inorganic and organic substances of the
tooth, respectively (Soames and Southam, 2005). In horses, two variants of dental
caries occur: equine dental peripheral caries (PC) involving the periphery of teeth;
and infundibular caries (IC) of the maxillary cheek teeth.
Twenty-five veterinarians and equine dental technicians experienced in equine
dentistry were recruited to perform a UK-wide survey and examined 706 horses for
the presence PC and IC, as well as for concurrent dental disorders. The recorded
survey results for individual horses included data on potential risk factors including
breed, sex, age, diet and the postcode of stables. The prevalence of PC and IC in this
population, was 51.7% and 45.5%, respectively. The most commonly and severely
PC affected teeth were the three caudal cheek teeth (Triadan 09-11) and for IC were
the Triadan 09s. In a multivariable model without observer as a random effect,
potential risk factors for the development of PC were: the presence of IC, the
presence of diastema/periodontal disease (PD), the presence of multiple concurrent
dental disorders other than IC, being fed 2.1-3.0 kg concentrates per day, and living
in South East England and South West England. The risk factors which remained
significantly associated with the presence of PC in a multivariable model with
observer as a random effect, were: feeding 2.1-3 kg concentrates per day, multiple
concurrent dental disorders other than IC, the presence of diastema/periodontal
disease; additionally, dental fractures now became significantly associated with the
presence of PC. In a multivariable model without observer as a random effect,
potential risk factors for the development of IC were: the presence of PC, the
presence of multiple dental disorders other than IC, and increasing age. Horses in
North England and South West England were significantly less likely to have IC than
horses in other regions of England and Scotland. In a multivariable model with
observer as random effect, the only remaining risk factors were increasing age and
geographical region, with a significantly lower likelihood for horses to have IC in
South West England than in the other regions.
A molecular microbiological study on equine dental caries using a linear
discriminant analysis effect size (LEfSe) at genus or higher level, showed Gemella
and Actinobacillus to be the genera most associated with the PC study control group
(no PC), and Streptococcus, Olsenella and Scardovia to be the genera most
associated with PC. Additionally if LEfSe was performed at genus level only, then an
additional genus shown to be associated with PC was Mitsuokella. The genus most
associated with IC using LEfSe at genus or higher level was Acidaminococcus, while
Bacillus was the genus most associated with the IC study control group (no IC).
A pathological study examined PC-affected cheek teeth grossly, histologically and,
by scanning electron microscopy (SEM) and transmission electron microscopy
(TEM). Dental plaque, containing bacteria was found to cover the PC lesions. In
peripheral cementum, PC lesions were categorised by their shape on histological
cross sections of affected teeth into: flake-type, flask-like, or ellipsoid-shaped lesions
or combinations of these patterns. Bacteria from surface lesions penetrated between
Sharpey’s fibers of cementum in a direction perpendicular to the peripheral aspect of
the tooth, destroying the intrinsic fibres and Sharpey’s fibers. Bacteria also
penetrated in a direction parallel to the peripheral aspect of the tooth, undermining
the intrinsic fibres, including at the level of incremental growth lines. Bacteria were
also found in ellipsoid-shaped lesions and in cemental lacunae of affected cementum.
In dentine affected by PC, bacteria were found within and between damaged dentinal
tubules, sometimes causing flake-type lesions similar to those seen in cementum.
Bacteria penetrated primary dentine and/or (regular/irregular) secondary dentine
from the occlusal surface, or entered primary dentine through cementum and enamel
from the peripheral aspect. Dental plaque containing bacteria were sometimes
observed in dentinal fissure fractures.
PC of enamel was only visible using SEM, because this was the only method which
did not require prior decalcification, that almost completely removed enamel.
In conclusion, PC and IC are prevalent dental disorders in the examined British
equine population. The association between PC and concurrent dental disorders
(multiple concurrent dental disorders, diastemata/periodontal disease and dental
fractures), indicates that these should be addressed in affected horses. In horses
affected by IC, the focus should be on treatment of IC itself (like infundibular
fillings), because associations of IC were found with risk factors which cannot (or
not easily) be controlled such as age and region. Several bacteria could be identified
which were associated with PC and other bacteria were more associated with IC or
control groups. It was confirmed in the pathological study that bacteria penetrate the
cheek teeth affected by PC and IC. So the focus of treatment of PC and IC can also
be on reducing the bacteria associated with PC and IC respectively, or the focus
could be on prevention by making the teeth more resistant against caries by fluoride
treatment. A critical assessment of the use of chlorhexidine mouthwashes and
supplementation of fluoride are needed to evaluate its potential effects on PC and IC
Products and Services
Today’s global economy offers more opportunities, but is also more complex and competitive than ever before. This fact leads to a wide range of research activity in different fields of interest, especially in the so-called high-tech sectors. This book is a result of widespread research and development activity from many researchers worldwide, covering the aspects of development activities in general, as well as various aspects of the practical application of knowledge
Interval orders without odd crowns are defect optimal
SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Interval orders without odd crowns are defect optimal
SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Ceramic Materials
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Superconductors at the Nanoscale
By covering theory, design, and fabrication of nanostructured superconducting materials, this monograph is an invaluable resource for research and development. Examples are energy saving solutions, healthcare, and communication technologies. Key ingredients are nanopatterned materials which help to improve the superconducting critical parameters and performance of superconducting devices, and lead to novel functionalities. Contents Tutorial on nanostructured superconductors Imaging vortices in superconductors: from the atomic scale to macroscopic distances Probing vortex dynamics on a single vortex level by scanning ac-susceptibility microscopy STM studies of vortex cores in strongly confined nanoscale superconductors Type-1.5 superconductivity Direct visualization of vortex patterns in superconductors with competing vortex-vortex interactions Vortex dynamics in nanofabricated chemical solution deposition high-temperature superconducting films Artificial pinning sites and their applications Vortices at microwave frequencies Physics and operation of superconducting single-photon devices Josephson and charging effect in mesoscopic superconducting devices NanoSQUIDs: Basics & recent advances intrinsic Josephson junction stacks as emitters of terahertz radiation| Interference phenomena in superconductor-ferromagnet hybrids Spin-orbit interactions, spin currents, and magnetization dynamics in superconductor/ferromagnet hybrids Superconductor/ferromagnet hybrid
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