Imaging of the formerly bonded area of individual fibre to fibre joints with SEM and AFM

Cellulose ◽  
2013 ◽  
Vol 21 (1) ◽  
pp. 251-260 ◽  
Author(s):  
Wolfgang J. Fischer ◽  
Armin Zankel ◽  
Christian Ganser ◽  
Franz J. Schmied ◽  
Hartmuth Schroettner ◽  
...  
Keyword(s):  
Individual Fibre

scholarly journals Individual fibre inclination segmentation from X-ray computed tomography using principal component analysis

2021 ◽  
pp. 002199832110527
Author(s):  
Filip B Salling ◽  
Niels Jeppesen ◽  
Mads R Sonne ◽  
Jesper H Hattel ◽  
Lars P Mikkelsen
Keyword(s):  
Computed Tomography ◽  
Principal Component Analysis ◽  
Principal Component ◽  
Component Analysis ◽  
X Ray ◽  
Segmentation Approach ◽  
Inclination Angles ◽  
Glass Fibre Reinforced ◽  
X Ray Computed ◽  
Individual Fibre

This study presents a holistic segmentation procedure, which can be used to obtain individual fibre inclination angles from X-ray computed tomography. The segmentation approach is based on principal component analysis and was successfully applied for a unidirectional and an air-textured glass fibre–reinforced composite profile. The inclination results show a weighted mean fibre inclination of 2.1° and 8.0° for the unidirectional and air-textured profile, respectively. For the air-textured composite, fibre inclinations of up to 55° were successfully segmented. The results were verified by comparative analysis with equivalent results obtained from structure tensor analysis – showing no notable deviation. The comparable characteristics in combination with the distinct differences of the two material systems make this case study ideal for verification and validation of idealized models. It is shown how this approach can provide fast, accurate and repeatable inclination estimates with a high degree of automation.

scholarly journals Statistical validation of individual fibre segmentation from tomograms and microscopy

2018 ◽  
Vol 160 ◽  
pp. 208-215 ◽  
Author(s):  
Monica Jane Emerson ◽  
Vedrana Andersen Dahl ◽  
Knut Conradsen ◽  
Lars Pilgaard Mikkelsen ◽  
Anders Bjorholm Dahl
Keyword(s):  
Statistical Validation ◽  
Individual Fibre

scholarly journals Tensile behaviour of individual fibre bundles in the human lumbar anulus fibrosus

2018 ◽  
Vol 67 ◽  
pp. 24-31 ◽  
Author(s):  
Diana T. Pham ◽  
Joe G. Shapter ◽  
John J. Costi
Keyword(s):  
Tensile Behaviour ◽  
Anulus Fibrosus ◽  
Fibre Bundles ◽  
Individual Fibre

The development of the fleece and follicle population in Herdwick sheep

1954 ◽  
Vol 44 (4) ◽  
pp. 443-464 ◽  
Author(s):  
Marca Burns
Keyword(s):  
Numerical Data ◽  
Short Length ◽  
Fibre Types ◽  
Winter Period ◽  
Two Generations ◽  
The Face ◽  
Vigorous Growth ◽  
Typical Shape ◽  
The Mean ◽  
Individual Fibre

1. The development of the fleece and follicle population was studied in six Herdwick and two Herdwick × Swaledale sheep on their native farm in Cumberland. Six of these sheep survived the first 14 months of the experiment, and four were kept under observation for a further 12 months. Growth in body weight, body surface area, and area of tattooed squares was recorded and discussed.2. Fibre type arrays (at the mid-side positions) were ‘Plateau’ in all but one of the pure Herdwick lambs, and ‘Saddle’ in the remaining three animals.3. The earliest fibres of the array (halos and coarse super-sickles) were mostly ribbon-shaped in their pre-natal and early post-natal portions, below which they became cylindrical. These fibres were ‘birth coat kemps’ and were shed about 10 weeks after birth. At this time later-developed fibres (sickles and curly-tips) showed ‘crisis thinning’ but did not shed, whilst late curly tips and histerotrichs were not affected. These three groups gave rise to three corresponding groups of fibres in the adult fleece, namely kemps, hairs and fine fibres.4. Two generations of kemp fibres were grown each year, ‘spring kemps’ commencing growth about April and shedding by July; and ‘autumn kemps’ commencing growth in July and forming ‘brush-roots’ in the autumn and early winter, although the majority remain in their follicles until the following spring.5. The majority of the curly tip fibres of the birth coat grow into long hair fibres, which are of hetero-typical shape. In summer they are more or less coarse, and medullated, whilst in winter they become fine and lose their medulla; many cease growth during the middle of the winter period after producing a short length of fine fibre, and commence growth again in the spring. The late curly tip and histerotrichs fibres continue to grow as the fine undercoat fibres of the fleece, without any medullation.6. A large proportion of both primary and secondary follicles shed their fibres during the winter months. When this proportion is sufficiently high this leads to a severe ‘winter break’ in the wool staple. The visible ‘break’ is the result of the combined effect of the winter fining of heterotype hairs and the shedding of some of all types. Fibres traversing the break were found to be either long heterotypes or long fine fibres.7. The adult colour of any individual Herdwick sheep is the result of the interaction of several factors of which the main ones are: (1) later fibre types tend to be less pigmented than early types; (2) less vigorous growth of an individual fibre tends to reduce its pigmentation; (3) a more or less extensive acromelanic pigmentation; (4) the white areas may be affected by various degrees of speckling or roaning; (5) the kemp-like hairs of the face and legs are black at birth, and these are eventually shed and replaced by similar but unpigmented fibres.8. Numerical data on the fibre and follicle population are presented. The mean proportion of the three main fibre types (all sheep, all seasons) was: coarse 18%, medium 25%, fine 59%. The mean adult follicle density was 1012 per sq.cm. and the mean adult S/P ratio was 3·37:1.

scholarly journals Long-term development of white matter fibre density and morphology up to 13 years after preterm birth

2020 ◽  
Author(s):  
Claire E Kelly ◽  
Deanne K Thompson ◽  
Sila Genc ◽  
Jian Chen ◽  
Joseph YM Yang ◽  
...  
Keyword(s):  
Risk Factors ◽  
White Matter ◽  
Corpus Callosum ◽  
Childhood And Adolescence ◽  
Fibre Tract ◽  
Perinatal Risk Factors ◽  
Perinatal Risk ◽  
Fibre Density ◽  
Individual Fibre

AbstractBackgroundIt is well documented that infants born very preterm (VP) are at risk of brain injury and altered brain development in the neonatal period, however there is a lack of long-term, longitudinal studies on the effects of VP birth on white matter development over childhood. Most previous studies were based on voxel-averaged, non-fibre-specific diffusion magnetic resonance imaging (MRI) measures, such as fractional anisotropy. In contrast, the novel diffusion MRI analysis framework, fixel-based analysis (FBA), enables whole-brain analysis of microstructural and macrostructural properties of individual fibre populations at a sub-voxel level. We applied FBA to investigate the long-term implications of VP birth and associated perinatal risk factors on fibre development in childhood and adolescence.MethodsDiffusion images were acquired for a cohort of VP (born <30 weeks’ gestation) and full-term (FT, ≥37 weeks’ gestation) children at two ages: mean (SD) 7.6 (0.2) years (n=138 VP and 32 FT children) and 13.3 (0.4) years (n=130 VP and 45 FT children). 103 VP and 21 FT children had images at both ages for longitudinal analysis. At every fixel (individual fibre population within an image voxel) across the white matter, we compared FBA metrics (fibre density (FD), cross-section (FC) and a combination of these properties (FDC)) between VP and FT groups cross-sectionally at each age, and longitudinally between ages. We also examined associations between perinatal risk factors and FBA metrics in the VP group.ResultsCompared with FT children, VP children had lower FD, FC and FDC throughout the white matter, particularly in the corpus callosum, tapetum, inferior fronto-occipital fasciculus, fornix and cingulum at ages 7 and 13 years, as well as the motor pathways at age 13 years. VP children also had slower FDC development in the corpus callosum and corticospinal tract between ages 7 and 13 years compared with FT children. Within VP children, earlier gestational age at birth, lower birth weight z-score, and neonatal brain abnormalities were associated with lower FD, FC and FDC throughout the white matter at both ages.ConclusionsVP birth and concomitant perinatal risk factors are associated with fibre tract-specific alterations to axonal development in childhood and adolescence.

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