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1

Effects of scan circle displacement in optical coherence tomography retinal nerve fibre layer thickness measurement: a RNFL modelling study  

Microsoft Academic Search

ObjectiveTo study the effect of optical coherence tomography (OCT) scan circle displacement on retinal nerve fibre layer (RNFL) measurement errors using cubic spline models.MethodsForty-nine normal subjects were included in the analysis. In one randomly selected eye in each subject, RNFL thickness around the optic disc was measured by taking 16 circular scans of different sizes (scan radius ranged from 1

C Y L Cheung; C K F Yiu; R N Weinreb; D Lin; H Li; A Y Yung; C P Pang; D S C Lam; C K S Leung; CKS Leung

2009-01-01

2

Relative course of retinal nerve fiber layer (RNFL) birefringence, RNFL thickness and retinal function changes after optic nerve transection  

PubMed Central

Purpose To test the hypothesis that alterations of RNFL birefringence precede changes in RNFL thickness (RNFLT) in an experimental model of RGC injury. Secondarily, to determine the time course of RGC functional abnormalities relative to RNFL birefringence and RNFL thickness changes. Methods RNFL birefringence was measured by scanning laser polarimetery (GDx VCC, Carl Zeiss Meditec, Inc). RNFL thickness was measured by spectral domain optical coherence tomography (sd-OCT, Spectralis™ HRA+OCT, Heidelberg Engineering, GmbH). Retinal function was assessed by three forms of electroretinography (ERG): slow-sequence multifocal ERG (mfERG, VERIS, EDI); pattern-reversal ERG (PERG, Utas-E3000, LKC Technologies, Inc); and photopic full-field flash ERG (ff-ERG, Utas-E3000). All measurements were obtained in both eyes of four adult rhesus macaque monkeys (Macaca mulatta) during two baseline sessions, and again 1-week and 2-weeks after unilateral optic nerve transection (ONT). Results ONT was successfully completed in 3 subjects. RNFL birefringence declined by 15% one week after ONT (p = 0.043), while there was no significant change in RNFL thickness (+1%, p = 0.42). Two weeks after ONT, RNFL retardance had declined by 39% (p = 0.018) while RNFL thickness had declined by only 15% (p = 0.025). RGC functional abnormalities were present 1-week after ONT, including decreased amplitudes relative to baseline of the mfERG high frequency components (?65%, p = 0.018); the PERG N95 component (?70%, p = 0.007) and the photopic negative response of the ff-ERG (?44%, p = 0.005). Conclusions RNFL birefringence declined prior to, and faster than RNFL thickness after ONT. RGC functional abnormalities were present 1-week after ONT, when RNFL thickness had not yet begun to change. RNFL birefringence changes after acute RGC injury are associated with RGC dysfunction. Together, they reflect RGC abnormalities that precede axonal caliber changes and loss.

Fortune, Brad; Cull, Grant A.; Burgoyne, Claude F.

2009-01-01

3

Laser scanning tomography of localised nerve fibre layer defects  

Microsoft Academic Search

AIMSRetinal nerve fibre layer photography is a well established method to qualitatively document early structural changes which might be induced by primary open angle glaucoma. The aim was to analyse localised retinal nerve fibre layer (RNFL) defects in a new quantitative way with respect to surface topography, defect width, and surface reflectivity by means of the technique of confocal scanning

Reinhard O W Burk; Anja Tuulonen; P Juhani Airaksinen

1998-01-01

4

Study of retinal nerve fibre layer thickness in eyes with high tension glaucoma and hemifield defect  

Microsoft Academic Search

AIMTo quantitatively evaluate retinal nerve fibre layer (RNFL) difference in areas of apparently normal appearing visual field in eyes with high tension glaucoma (HTG) and hemifield defects using scanning laser polarimetry.METHODS40 eyes from 40 patients with HTG with superior or inferior hemifield defects based on the Humphrey field analyser (HFA) underwent RNFL thickness measurements. 20 normal eyes from 20 subjects

Michael S Kook; Kyung-rim Sung; Soontae Kim; Weechang Kang

2001-01-01

5

Relation between size of optic disc and thickness of retinal nerve fibre layer in normal subjects  

PubMed Central

AIMS—To evaluate the relation between the optic disc size and the thickness of the peripapillary retinal nerve fibre layer (RNFL) in normal Japanese subjects by means of scanning laser polarimetry.?METHODS—Scanning laser polarimetry was performed in 60 normal subjects. One eye of each subject was randomly selected for study. Using a scanning laser polarimeter, the integral of RNFL thickness was measured totally and regionally within a circular band located 1.75 disc diameters from the centre of the optic disc. The correlation between the optic disc size and the integral of RNFL thickness was examined.?RESULTS—The optic disc size showed a significant correlation with the integral of RNFL thickness (R = 0.497, p <0.001). A significant negative correlation was observed between the optic disc size and the ratio of inferior integral to total integral of RNFL thickness (R = ?0.274, p = 0.034).?CONCLUSIONS—The cross sectional area occupied by the RNF, measured by scanning laser polarimetry increased significantly with an increase in optic disc size while the ratio of inferior to total cross sectional area decreased significantly. These facts should be considered when one evaluates the RNFL thickness in patients with progressive optic neuropathies such as glaucoma.?? Keywords: scanning laser polarimeter; normal subjects; optic disc; retinal nerve fibre layer

Funaki, S.; Shirakashi, M.; Abe, H.

1998-01-01

6

Peripapillary retinal nerve fibre layer thickness in highly myopic Caucasians as measured by Stratus optical coherence tomography  

Microsoft Academic Search

Aims:To assess peripapillary retinal nerve fibre layer (RNFL) thickness distribution in a group of non-glaucomatous Caucasian subjects with a high degree of myopia and to evaluate the relationship between RNFL thickness, both global and sectoral, and other variables including axial length and optic disc size.Method:31 eyes of 31 healthy Caucasian subjects with spherical equivalent ??6 dioptres (D) were recruited from

S A Vernon; A P Rotchford; A Negi; S Ryatt; C Tattersal

2008-01-01

7

Reproducibility and agreement in evaluating retinal nerve fibre layer thickness between Stratus and Spectralis OCT  

PubMed Central

Purpose To evaluate intra-device reproducibility of retinal nerve fibre layer (RNFL) measurements obtained using Stratus and Spectralis optical coherence tomography, and to analyze inter-device correlation and agreement for these measurements. Design Prospective observational study. Methods A total of 30 normal individuals participated in the study. One eye of each participant was scanned three times during one session by the same operator using Spectralis and Stratus. Intra-class correlation coefficients (ICCs), correlation coefficients (R), and Bland–Altman plots (BAPs) were used to assess reproducibility, correlation, and agreement between the two devices, respectively. Results A significant difference in mean RNFL thickness was seen between Stratus and Spectralis (106.2±6.9??m vs100.0±7.3??m, P=0.0001). ICCs of RNFL thickness measurements ranged from 0.69 (clock hour 2; 95% confidence interval (95% CI): 0.54, 0.85) to 0.91 (inferior quadrant; 95% CI: 0.86, 0.96) for Stratus and were higher for Spectralis, ranging from 0.87 (temporal-superior sector; 95% CI: 0.79, 0.94) to 0.96 (global and nasal-inferior sector; 95% CI: 0.94, 0.99). Rs of RNFL thickness measurements between the two instruments ranged from 0.61 (temporal quadrant) to 0.87 (superior quadrant). BAPs demonstrated a systematic difference in RNFL values between the two devices, with Spectralis producing thinner RNFL values than Stratus. Conclusions Spectralis demonstrated higher ICCs and thinner RNFL measurements than Stratus. Although the inter-device correlation was good, differences in RNFL measurements obtained by the two devices indicate that these measurements would not be interchangeable in clinical evaluations.

Arthur, S N; Smith, S D; Wright, M M; Grajewski, A L; Wang, Q; Terry, J M; Lee, M S

2011-01-01

8

Optic nerve atrophy and retinal nerve fibre layer thinning following optic neuritis: Evidence that axonal loss is a substrate of MRI-detected atrophy  

Microsoft Academic Search

Magnetic resonance imaging (MRI) measures of brain atrophy are often considered to be a marker of axonal loss in multiple sclerosis (MS) but evidence is limited. Optic neuritis is a common manifestation of MS and results in optic nerve atrophy. Retinal nerve fibre layer (RNFL) imaging is a non-invasive way of detecting axonal loss following optic neuritis. We hypothesise that

S. Anand Trip; Patricio G. Schlottmann; Stephen J. Jones; Wai-Yung Li; David F. Garway-Heath; Alan J. Thompson; Gordon T. Plant; David H. Miller

2006-01-01

9

Bragg fibres with an intermediate layer  

SciTech Connect

This paper examines the effect of an intermediate layer between the core and periodic cladding of a Bragg fibre on its optical properties. It is shown that any TE{sub 0{kappa}} mode of a standard Bragg fibre can be transformed into the fundamental mode of a Bragg fibre with an intermediate layer by adjusting the thickness of the first cladding layer. Varying the thickness of the intermediate layer, one can tune the mode composition of the transmitted light in a periodic manner. The periodic variation of the optical loss with the thickness of the intermediate layer is due to resonances and antiresonances in this layer. The resonances correspond to two-mode light propagation through the fibre, whereas the antiresonances, to single-mode light propagation.

Kulchin, Yurii N; Zinin, Yu A; Nagornyi, I G

2012-03-31

10

Attenuation of the retinal nerve fibre layer and reduced retinal function assessed by optical coherence tomography and full-field electroretinography in patients exposed to vigabatrin medication.  

PubMed

Purpose:? To investigate the clinical value of assessment of peripapillary retinal nerve fibre layer (RNFL) thickness with OCT in addition to the evaluation of retinal function measured by full-field electroretinography (ff-ERG) in patients with suspected vigabatrin (VGB)-attributed visual field defects. Methods:? Visual fields from adult patients in our clinical follow-up program for VGB medication were analysed. Twelve patients with suspected VGB-attributed visual field defects were selected for the study. They were re-examined with computerized kinetic perimetry, ff-ERG and OCT (2D circle scan). Results:? Constricted visual fields were found in all patients. Comparative analysis of ff-ERG parameters showed reduced b-wave amplitudes for the isolated and the combined rod and cone responses (p?RNFL in nine of 12 patients, most frequently superiorly and/or inferiorly. No temporal attenuation was found. Significant positive correlations were found between the total averaged RNFL thickness, superior and inferior RNFL thickness and reduced ff-ERG parameters. Positive correlations were also found between RNFL thickness and isopter areas. Conclusion:? OCT measurements can detect attenuation of the RNFL in patients exposed to VGB medication. RNFL thickness correlates with reduced ff-ERG parameters and isopter areas of constricted visual fields, indicating that VGB is retino-toxic on several levels, from photoreceptors to ganglion cells. The study also supports previous studies, suggesting that OCT measurement of the RNFL thickness may be of clinical value in monitoring patients on vigabatrin therapy. PMID:23387307

Kjellström, Ulrika; Andréasson, Sten; Ponjavic, Vesna

2013-02-01

11

Effect of fibre size on the quality of fibre-enriched layer cakes  

Microsoft Academic Search

The effects of fibre type (wheat bran, oat bran, cellulose microcrystalline), size (50, 80, 250?m) and percentage of substitution (0%, 12%, 24%, 36%) on batter and layer cake characteristics were determined. Batter density, and the rheological parameters (G? and G?) increased with fibre size, but the flow index decreased. Especially with 20% wheat bran, large-sized fibre gave the most firm,

Manuel Gómez; Ana Moraleja; Bonastre Oliete; Elena Ruiz; Pedro A. Caballero

2010-01-01

12

Retinal Nerve Fibre Layer Thickness and Contrast Sensitivity in HIV-Infected Individuals in South Africa: A Case-Control Study  

PubMed Central

Background Antiretroviral treatment (ART) has altered the spectrum of HIV-related eye disease, resulting in a lower prevalence of retinal opportunistic infections (OIs). However, abnormalities in visual function have been reported in HIV-infected individuals despite effective viral suppression and the absence of retinal OIs. These changes may be mediated by an HIV-associated ‘neuroretinal disorder’, characterized by changes in the retinal nerve fibre layer (RNFL). HIV infection may also be associated with accelerated biological aging. The aim of this study was to investigate the relationships between contrast sensitivity, RNFL thickness, HIV infection and frailty in South African adults. Methods Case-control study of 225 HIV-infected individuals without retinal OIs and 203 gender/age-matched HIV-seronegative individuals. Peri-papillary RNFL thickness was determined with spectral domain optical coherence tomography in four quadrants. CS was measured using a Pelli-Robson chart. Frailty was assessed using standard criteria. Multivariable linear and logistic regression were used to assess associations between HIV status and RNFL/CS and frailty. Results The median age of both groups was similar (41.2 vs. 41.9 years, p?=?0.37). 88% of HIV-infected individuals were receiving ART and their median CD4 count was 468 cells/?l. Adjusted CS score was lower in HIV-infected participants compared to HIV-seronegative individuals (1.76 vs. 1.82, p?=?0.002). Independent predictors of poor CS in the HIV-infected group were positive frailty status and current HIV viral load >2 log copies/ml. Lower CS score was also associated with thin temporal RNFL in HIV-infected individuals (p?=?0.04). Superior quadrant RNFL thickness was greatest in ART-naïve participants relative to the HIV-uninfected group (p-trend?=?0.04). Longer ART duration was associated with thinning of inferior and nasal RNFL quadrants (p-trend?=?0.03 and 0.04, respectively). Conclusions Contrast sensitivity is reduced in HIV-infected individuals and functionally associated with frailty and unsuppressed viraemia. This may reflect structural changes in the RNFL that are evident despite the absence of OIs.

Pathai, Sophia; Lawn, Stephen D.; Weiss, Helen A.; Cook, Colin; Bekker, Linda-Gail; Gilbert, Clare E.

2013-01-01

13

Heterogeneous Pattern of Retinal Nerve Fiber Layer in Multiple Sclerosis. High Resolution Optical Coherence Tomography: Potential and Limitations  

Microsoft Academic Search

BackgroundRecently the reduction of the retinal nerve fibre layer (RNFL) was suggested to be associated with diffuse axonal damage in the whole CNS of multiple sclerosis (MS) patients. However, several points are still under discussion. (1) Is high resolution optical coherence tomography (OCT) required to detect the partly very subtle RNFL changes seen in MS patients? (2) Can a reduction

Nermin Serbecic; Fahmy Aboul-Enein; Sven C. Beutelspacher; Martin Graf; Karl Kircher; Wolfgang Geitzenauer; Werner Brannath; Priska Lang; Wolfgang Kristoferitsch; Hans Lassmann; Andreas Reitner; Ursula Schmidt-Erfurth; Christoph Kleinschnitz

2010-01-01

14

Morphometric evaluation of changes with time in optic disc structure and thickness of retinal nerve fibre layer in chronic ocular hypertensive monkeys  

Microsoft Academic Search

We examined the time course of changes in optic disc structure by means of a scanning laser ophthalmoscope (Heidelberg Retina Tomograph, HRT) in ocular hypertensive (experimental glaucoma) monkeys, and clarified the relationships between the histological RNFL thickness and HRT parameters. Further, the time course of changes in retinal nerve fiber layer (RNFL) thickness in individual eyes was measured using a

Masamitsu Shimazawa; Goji Tomita; Takazumi Taniguchi; Masaaki Sasaoka; Hideaki Hara; Yoshiaki Kitazawa; Makoto Araie

2006-01-01

15

Ultrastructure of rabbit retinal nerve fibre layer--neuro-glial relationships, myelination, and nerve fibre spectrum.  

PubMed

The ultrastructure of the rabbit retinal nerve fibre layer was studied both in retinal centre and periphery. The central nerve fibre layer was found to contain large masses of--mostly myelinated--nerve fibres, somata and processes of astrocytes and oligodendrocytes, vitreal processes of Müller cells, and blood vessels. Astrocyte and Müller cell processes could be discriminated both by their direction and by the thickness of their intermediate filaments which was about 7 nm in Müller cells and about 10 nm in astrocytes. Some peculiarities of nuclei and cytoplasmic organelles of rabbit retinal astrocytes and oligodendrocytes are described. Myelin sheaths are demonstrated to be derived from oligodendrocytes; in some cases, two axons were found within a common myelin sheath. In the retinal periphery, only sparse thin bundles of unmyelinated axons were found in between a thick row of big Müller cell endfeet; astrocytes, oligodendrocytes, and blood vessels were missing here. In both retinal regions, node-like membrane specializations of optic axons were found; these were always surrounded by a corona of fine glial processes arising from astrocytes as well as from Müller cells. The features of myelination within the rabbit nerve fibre layer were quantified, and compared with recent literature data. A hypothesis is offered relating the production of myelin to the release of diffusable substance(s) by active axons. This hypotheses allows to account for the striking finding that relatively thick axons remain unmyelinated in the nerve fibre layer of most mammalian retinae like in the rabbit retinal periphery whereas they become myelinated in the central rabbit retina like in central nervous system in general. PMID:3216098

Reichenbach, A; Schippel, K; Schümann, R; Hagen, E

1988-01-01

16

Quantitative RNFL attenuation coefficient measurements by RPE-normalized OCT data  

NASA Astrophysics Data System (ADS)

We demonstrate significantly different scattering coefficients of the retinal nerve fiber layer (RNFL) between normal and glaucoma subjects. In clinical care, SD-OCT is routinely used to assess the RNFL thickness for glaucoma management. In this way, the full OCT data set is conveniently reduced to an easy to interpret output, matching results from older (non- OCT) instruments. However, OCT provides more data, such as the signal strength itself, which is due to backscattering in the retinal layers. For quantitative analysis, this signal should be normalized to adjust for local differences in the intensity of the beam that reaches the retina. In this paper, we introduce a model that relates the OCT signal to the attenuation coefficient of the tissue. The average RNFL signal (within an A-line) was then normalized based on the observed RPE signal, resulting in normalized RNFL attenuation coefficient maps. These maps showed local defects matching those found in thickness data. The average (normalized) RNFL attenuation coefficient of a fixed band around the optic nerve head was significantly lower in glaucomatous eyes than in normal eyes (3.0mm-1 vs. 4.9mm-1, P<0.01, Mann-Whitney test).

Vermeer, K. A.; van der Schoot, J.; Lemij, H. G.; de Boer, J. F.

2012-02-01

17

Stress analysis of lap joints involving natural fibre reinforced interface layers  

Microsoft Academic Search

This paper is concerned with a fatigue study of composite adhesive lap joints. The tests were carried out on specimen joints manufactured using different stacking sequences: solely bi-directional woven E-glass fibres and polypropylene composites; and hybrid stacked composites. The main objective of the work was to improve the fatigue strength using hybrid fibre composites with a polypropylene\\/hemp natural fibre layer

J. M. Ferreira; H. Silva; J. D. Costa; M. Richardson

2005-01-01

18

Embedding metallic jacketed fused silica fibres into stainless steel using additive layer manufacturing technology  

NASA Astrophysics Data System (ADS)

Metal clad single mode optical fibres are successfully embedded into stainless steel using a layer by layer based additive manufacturing technology based on selective laser sintering of powered stainless steel material. The single mode fibre has been coated with a protective Ni metal layer to facilitate thermal protection and bonding to the stainless steel matrix. A loss of ~1 dB is observed after embedding which is attributed to micro bending in the embedded section.

Maier, Robert R. J.; Havermann, Dirk; MacPherson, William N.; Hand, Duncan P.

2013-05-01

19

Optical fibre sensor coated with porous silica layers for gas and chemical vapour detection  

Microsoft Academic Search

Fibre optic sensors have been conceived in new technologies for detecting very small amounts of chemical, gaseous and biological species. Recently, new polymer-clad silica (PCS) fibres coated with thin porous silica layers have been developed. These porous layers have been prepared by the sol-gel method using the dip-coating technique. In this work, this new material has been investigated for detecting

A. Abdelghani; J. M. Chovelon; N. Jaffrezic-Renault; M. Lacroix; H. Gagnaire; C. Veillas; B. Berkova; M. Chomat; V. Matejec

1997-01-01

20

Effects of increasing the fibre content of a layer diet  

Microsoft Academic Search

1. The fibre content of a basal diet fed to laying hens was increased from 149·2 g to between 218·6 and 292·3 g\\/kg by the inclusion of various fibrous farm wastes and by?products at 200 g\\/kg diet.2. The fibrous ingredients lowered the metabolisable energy (ME) of the basal diet from 11·82 to between 9·31 and 11·21 MJ\\/kg.3. Utilisation (g food\\/kg

O. G. Longe

1984-01-01

21

Method for comparing visual field defects to local RNFL and RGC damage seen on frequency domain OCT in patients with glaucoma.  

PubMed Central

To relate structural (anatomical) and functional (behavioral) measures of glaucomatous damage, a method is described for comparing visual field defects to local retinal ganglion cell (RGC) and retinal nerve fiber layer (RNFL) thicknesses. Thickness maps of the RNFL and the RGC + inner plexiform layer, obtained with frequency domain optical coherence tomography (fdOCT), were transformed into probability maps by comparing them to a normative group. As demonstrated in patients with glaucomatous damage to the macula, the probability map associated with the patient’s visual field can be directly compared to the fdOCT probability maps by taking into consideration the displacement of the RGCs.

Hood, Donald C.; Raza, Ali S.

2011-01-01

22

ORMOSIL's layers as luminophores' matrices in an UV optical fibre's sensor  

NASA Astrophysics Data System (ADS)

The paper concerns the results of optical fibre's ultraviolet sensors' investigation. The cladding of the optical fibre's sensing part was removed and substituted with an active layer containing a coumarin's derivative designated with the number 3609. The dye acted as a transducer converting ultraviolet into visible radiation which could be easily detected. The theoretical modeling with the use of genetic algorithms proved that the best sensitivity of the sensor is achieved when the refractive indices of the active layer and the core are equal. Organically Modified Silica (ORMOSIL) matrices satisfy that condition as their refractive indices may be controlled and reach a value characteristic for the fused silica glass. However it may be expected that both the structure and the composition of ORMOSIL matrices may influence the organic dye's behaviour. The aim of the experiment presented in the paper was to measure the sensitivity of optical fibre sensors comprising the active layers composed of three alkoxysilanes which were methyltriethoxysilane (MTES), phenyltriethoxysilane (PhTES) and tetraethoxysilane (TEOS) as far as the sensitivity of the sensors with silica active layer derived from pure TEOS. Moreover, the influence of hydrolysis and condensation's time on the intensity of dye's luminescence both in active layers and sols' solutions was investigated. The results proved that hydrolysis time and gel's composition may influence a sensitivity of the sensor. Despite the initial decrease of luminescence's signal the long-lasting stability of UV/VIS conversion has been noticed which creates a possibility of the future practical application of the described sensors.

Rayss, Jan; Chodkowska, Eliza Maria; Czajkowski, Wojciech; Stolarski, Roland

2007-06-01

23

Quantitative evaluation of pigment particles in organic layers by fibre-optics diffuse-reflectance spectroscopy  

NASA Astrophysics Data System (ADS)

Fibre-optics diffuse-reflectance spectroscopy was used to evaluate pigment quantity in art glazes. Measurements are non-invasive, without any contact, and can be performed in situ, without moving the work of art under investigation from its conservation place. Reflectance spectra are processed using Kubelka Munk theory in order to obtain scattering and absorption parameters of the samples. Assuming a linear dependance of these optical properties with the pigment volume concentration of the paint layers, we were able to evaluate pigment quantities in the samples from reflectance measurements. Results are in excellent agreement with those obtained by X-ray diffraction and micro-X-ray fluorescence.

Dupuis, G.; Menu, M.

2005-02-01

24

Diagnostic ability of retinal nerve fiber layer maps to detect localized retinal nerve fiber layer defects.  

PubMed

PurposeTo evaluate and compare the diagnostic ability of spectral domain optical coherence tomography (SD-OCT) for detecting localized retinal nerve fiber layer (RNFL) defects in topographic RNFL maps and circumpapillary RNFL (cpRNFL) thickness measurements.MethodsSixty-four eyes with localized RNFL defects in red-free RNFL photographs and 72 healthy eyes were included. All participants were imaged with SD-OCT. The area and angular width of the localized RNFL defects were measured with ImageJ software on RNFL thickness map, significance map (yellow pixels, <5% level), and red-free RNFL photographs. The sensitivity, specificity, and area under the receiver operating characteristic curves (AUCs) were calculated for cpRNFL thickness, macular inner retina thickness, and RNFL maps (thickness, significance) according to the quantitative measurements and a <5% level of classification to distinguish eyes with localized RNFL defects from healthy eyes.ResultsRNFL thickness map (sensitivity 96.9-98.4%, specificity 86.1-98.6%, and AUCs 0.915-0.992) and significance map (sensitivity 96.9-98.4%, specificity 88.9-95.8%, and AUCs 0.937-0.983) showed superior performance in detecting localized RNFL defects compared with other parameters (P-value 0.001-0.024) except for 36 sector cpRNFL thickness (sensitivity 92.2%, specificity 87.5%, and AUCs 0.898; P-value 0.080-0.545). The sensitivity for detecting RNFL defects was related to the angular width, area, and depth of the RNFL defects in the cpRNFL (4 sector, 12 sector) and macular inner retinal measurements. RNFL thickness and significance maps showed a constant sensitivity regardless of variations in angular width, area, and depth of the RNFL defects.ConclusionRNFL thickness and significance maps could be used to distinguish eyes with localized RNFL defects from healthy eyes more effectively than cpRNFL thickness and macular inner retina thickness measurements. PMID:23743523

Shin, J W; Uhm, K B; Lee, W J; Kim, Y J

2013-06-07

25

The Ramifications and Terminals of Optic Fibres in Layers 2 and 3 of the Avian Optic Tectum: A Golgi and Light and Electron Microscopic Anterograde Tracer Study  

Microsoft Academic Search

The ramification patterns and terminals of optic fibres in layers 2 and 3 of the optic tectum were studied in Golgi-stained and immunolabelled preparations made from the brains of chicks and pigeons. The different neuronal structures of layers 2 and 3 were also examined. In Golgi preparations, two types of optic fibre were found both in chick and pigeon tectum

T. Tömböl; M. Eyre; N. Zayats; A. Németh

2003-01-01

26

Comparative study of the retinal nerve fibre layer thickness performed with optical coherence tomography and GDx scanning laser polarimetry in patients with primary open-angle glaucoma  

PubMed Central

Summary Background We compared the parameters of retinal nerve fibre layer in patients with advanced glaucoma with the use of different OCT (Optical Coherence Tomograph) devices in relation to analogical measurements performed with GDx VCC (Nerve Fiber Analyzer with Variable Corneal Compensation) scanning laser polarimetry. Material/Methods Study subjects had advanced primary open-angle glaucoma, previously treated conservatively, diagnosed and confirmed by additional examinations (visual field, ophthalmoscopy of optic nerve, gonioscopy), A total of 10 patients were enrolled (9 women and 1 man), aged 18–70 years of age. Nineteen eyes with advanced glaucomatous neuropathy were examined. 1) Performing a threshold perimetry Octopus, G2 strategy and ophthalmoscopy of optic nerve to confirm the presence of advanced primary open-angle glaucoma; 2) performing a GDx VCC scanning laser polarimetry of retinal nerve fibre layer; 3) measuring the retinal nerve fibre layer thickness with 3 different optical coherence tomographs. Results The parameters of the retinal nerve fibre layer thickness are highly correlated between the GDx and OCT Stratus and 3D OCT-1000 devices in mean retinal nerve fibre layer thickness, retinal nerve fibre layer thickness in the upper sector, and correlation of NFI (GDx) with mean retinal nerve fibre layer thickness in OCT examinations. Absolute values of the retinal nerve fibre layer thickness (measured in ?m) differ significantly between GDx and all OCT devices. Conclusions Examination with OCT devices is a sensitive diagnostic method of glaucoma, with good correlation with the results of GDx scanning laser polarimetry of the patients.

Wasyluk, Jaromir T.; Jankowska-Lech, Irmina; Terelak-Borys, Barbara; Grabska-Liberek, Iwona

2012-01-01

27

Opto-chemical fibre Bragg grating sensors based on evanescent field interaction with specific transducer layers  

Microsoft Academic Search

Fibre side-polishing technology allows for refractive index measurements using optical fibre Bragg grating sensors. Evanescent field interaction between the guided fibre light mode and the analyte near to the core of the side-polished optical fibre yields a Bragg wavelength shift in dependence on the refractive index of the analyte. This refractometric sensor technique has been extended to opto-chemical measurements with

Wolfgang Ecke; Kerstin Schroeder; Silvio Bierschenk; Reinhardt Willsch

2005-01-01

28

[The retinal nerve fiber layer in normal and glaucoma eyes].  

PubMed

Glaucoma leads to changes of the retinal nerve fiber layer (RNFL). This study was performed to evaluate glaucomatous alterations of the RNFL and to correlate them with other parameters of glaucomatous optic nerve damage. The study included red-free wide-angle fundus photographs of the RNFL of 453 normal eyes and 609 eyes with glaucoma. We evaluated the visibility of the RNFL in different fundus regions and the occurrence of localized RNFL defects. In the glaucoma eyes, including those with "early" glaucomatous optic nerve damage, the visibility of RNFL was significantly lower than in the normal eyes. The degree of RNFL visibility correlated with other morphological and perimetric parameters. Localized RNFL defects were detected in 20% of the glaucoma eyes. Their frequency increased significantly (P < 0.01) from an "early" glaucoma stage to a subgroup with medium advanced glaucomatous damage and decreased again to a stage with marked glaucomatous changes. They were significantly more common in eyes with normal pressure glaucoma, followed by eyes with primary open-angle glaucoma and finally eyes with secondary open-angle glaucoma. They were significantly associated with optic disk hemorrhages and notches of the neuroretinal rim. The results indicate that the glaucomatous changes of the RNFL are correlated with the optic disk alterations. This holds true also for eyes with "early" glaucomatous damage. It suggests that during every routine ophthalmoscopy the RNFL should be examined. Localized RNFL defects indicate optic nerve damage with a specificity of more than 90%. The contrast between localized and diffuse RNFL loss, the varying frequency of localized RNFL defects in different types of glaucoma and the association between localized RNFL defects and optic disk hemorrhages are diagnostically and pathogenetically important. PMID:8124022

Jonas, J B; Schiro, D; Naumann, G O

1993-12-01

29

Comparing rates of retinal nerve fibre layer loss with GDxECC using different methods of visual-field progression  

Microsoft Academic Search

BackgroundThis prospective analysis was designed to examine the rate of RNFL loss using scanning laser polarimetry (GDx enhanced corneal compensation (GDxECC)) in progressing versus non-progressing eyes using various methods to define functional progression.MethodsGlaucoma suspect and glaucomatous eyes with ?3 years of follow-up participating in the Advanced Imaging for Glaucoma Study were enrolled. All eyes underwent standard automated perimetry (SAP) and

Dilraj S Grewal; Mitra Sehi; David S Greenfield

2010-01-01

30

Decreased retinal nerve fibre layer thickness detected by optical coherence tomography in patients with ethambutol-induced optic neuropathy  

PubMed Central

Background It is difficult to assess the degree of optic nerve damage in patients with ethambutol?induced optic neuropathy, especially just after the onset of visual loss, when the optic disc typically looks normal. Aim To evaluate changes in retinal nerve fibre layer thickness (RNFLT) using optical coherence tomography (OCT) in patients with optic neuropathy within 3?months of cessation of ethambutol treatment. Design A retrospective observational case series from a single neuro?ophthalmology practice. Methods 8 patients with a history of ethambutol?induced optic neuropathy were examined within 3?months after stopping ethambutol treatment. All patients underwent a neuro?ophthalmologic examination, including visual acuity, colour vision, visual fields and funduscopy. OCT was performed on both eyes of each patient using the retinal nerve fibre layer analysis protocol. Results The interval between cessation of ethambutol treatment and the initial visit ranged from 1?week to 3?months. All patients had visual deficits characteristic of ethambutol?induced optic neuropathy at their initial visit, and the follow?up examination was performed within 12?months. Compared with the initial RNFLT, there was a statistically significant decrease in the mean RNFLT of the temporal, superior and nasal quadrants (p?=?0.009, 0.019 and 0.025, respectively), with the greatest decrease in the temporal quadrant (mean decrease 26.5??m). Conclusions A decrease in RNFLT is observed in all quadrants in patients with ethambutol?induced optic neuropathy who have recently discontinued the medication. This decrease is most pronounced in the temporal quadrant of the optic disc.

Chai, Samantha J; Foroozan, Rod

2007-01-01

31

Multimaterial piezoelectric fibres.  

PubMed

Fibre materials span a broad range of applications ranging from simple textile yarns to complex modern fibre-optic communication systems. Throughout their history, a key premise has remained essentially unchanged: fibres are static devices, incapable of controllably changing their properties over a wide range of frequencies. A number of approaches to realizing time-dependent variations in fibres have emerged, including refractive index modulation, nonlinear optical mechanisms in silica glass fibres and electroactively modulated polymer fibres. These approaches have been limited primarily because of the inert nature of traditional glassy fibre materials. Here we report the composition of a phase internal to a composite fibre structure that is simultaneously crystalline and non-centrosymmetric. A ferroelectric polymer layer of 30 mum thickness is spatially confined and electrically contacted by internal viscous electrodes and encapsulated in an insulating polymer cladding hundreds of micrometres in diameter. The structure is thermally drawn in its entirety from a macroscopic preform, yielding tens of metres of piezoelectric fibre. The fibres show a piezoelectric response and acoustic transduction from kilohertz to megahertz frequencies. A single-fibre electrically driven device containing a high-quality-factor Fabry-Perot optical resonator and a piezoelectric transducer is fabricated and measured. PMID:20622864

Egusa, S; Wang, Z; Chocat, N; Ruff, Z M; Stolyarov, A M; Shemuly, D; Sorin, F; Rakich, P T; Joannopoulos, J D; Fink, Y

2010-07-11

32

Multimaterial piezoelectric fibres  

NASA Astrophysics Data System (ADS)

Fibre materials span a broad range of applications ranging from simple textile yarns to complex modern fibre-optic communication systems. Throughout their history, a key premise has remained essentially unchanged: fibres are static devices, incapable of controllably changing their properties over a wide range of frequencies. A number of approaches to realizing time-dependent variations in fibres have emerged, including refractive index modulation, nonlinear optical mechanisms in silica glass fibres and electroactively modulated polymer fibres. These approaches have been limited primarily because of the inert nature of traditional glassy fibre materials. Here we report the composition of a phase internal to a composite fibre structure that is simultaneously crystalline and non-centrosymmetric. A ferroelectric polymer layer of 30?m thickness is spatially confined and electrically contacted by internal viscous electrodes and encapsulated in an insulating polymer cladding hundreds of micrometres in diameter. The structure is thermally drawn in its entirety from a macroscopic preform, yielding tens of metres of piezoelectric fibre. The fibres show a piezoelectric response and acoustic transduction from kilohertz to megahertz frequencies. A single-fibre electrically driven device containing a high-quality-factor Fabry-Perot optical resonator and a piezoelectric transducer is fabricated and measured.

Egusa, S.; Wang, Z.; Chocat, N.; Ruff, Z. M.; Stolyarov, A. M.; Shemuly, D.; Sorin, F.; Rakich, P. T.; Joannopoulos, J. D.; Fink, Y.

2010-08-01

33

High-Resolution Fibre-Optic Temperature Sensing: A New Tool to Study the Two-Dimensional Structure of Atmospheric Surface-Layer Flow  

NASA Astrophysics Data System (ADS)

We present a novel approach based on fibre-optic distributed temperature sensing (DTS) to measure the two-dimensional thermal structure of the surface layer at high resolution (0.25 m, ?0.5 Hz). Air temperature observations obtained from a vertically-oriented fibre-optics array of approximate dimensions 8 m × 8 m and sonic anemometer data from two levels were collected over a short grass field located in the flat bottom of a wide valley with moderate surface heterogeneity. The objectives of the study were to evaluate the potential of the DTS technique to study small-scale processes in the surface layer over a wide range of atmospheric stability, and to analyze the space-time dynamics of transient cold-air pools in the calm boundary layer. The time response and precision of the fibre-based temperatures were adequate to resolve individual sub-metre sized turbulent and non-turbulent structures, of time scales of seconds, in the convective, neutral, and stable surface layer. Meaningful sensible heat fluxes were computed using the eddy-covariance technique when combined with vertical wind observations. We present a framework that determines the optimal environmental conditions for applying the fibre-optics technique in the surface layer and identifies areas for potentially significant improvements of the DTS performance. The top of the transient cold-air pool was highly non-stationary indicating a superposition of perturbations of different time and length scales. Vertical eddy scales in the strongly stratified transient cold-air pool derived from the DTS data agreed well with the buoyancy length scale computed using the vertical velocity variance and the Brunt-Vaisala frequency, while scales for weak stratification disagreed. The high-resolution DTS technique opens a new window into spatially sampling geophysical fluid flows including turbulent energy exchange.

Thomas, Christoph K.; Kennedy, Adam M.; Selker, John S.; Moretti, Ayla; Schroth, Martin H.; Smoot, Alexander R.; Tufillaro, Nicholas B.; Zeeman, Matthias J.

2012-02-01

34

Large-deformation analysis of the elastic recoil of fibre layers in a Brinkman medium with application to the endothelial glycocalyx  

NASA Astrophysics Data System (ADS)

There is wide interest in the role of the endothelial surface layer (ESL) in transmitting blood shear stress to the intracellular cytoskeleton of the endothelial cell. However, very little is known about the mechanical properties of the glycocalyx or the flexural rigidity of the core proteins that comprise it. Vink, Duling & Spaan (FASEB J., vol. 13, 1999, p. A 11) measured the time-dependent restoration of the ESL after it had been nearly completely compressed by the passage of a white blood cell (WBC) in a tightly fitting capillary. Using this initial experiment, Weinbaum et al. (Proc. Natl. Acad. Sci. USA, vol. 100, 2003, p. 7988) predicted that the core proteins have a flexural rigidity EI of 700 pN nm(2) , which is ˜1/20 the measured value for an actin filament. However, their analysis assumes small deflections and only the fibre motion is considered. In the present paper we report additional experiments and apply large-deformation theory for ‘elastica’ to describe the restoration of the fibres in a Brinkman medium which absorbs fluid as the ESL expands. We find that there are two phases in the fibre recoil: an initial phase for large compressions where the ESL thickness is <0.36 its undisturbed thickness, and the ends of the fibres overlap and are parallel to the capillary wall; and a second phase where the fibres assume a shape that is close to the solutions for an elastic bar with linearly distributed vertical loading. The predicted time-dependent change in thickness of the ESL provides remarkably good agreement with experiment and yields an estimate of 490 pN nm(2) for the flexural rigidity EI of the core protein fibres, which is unexpectedly close to that predicted by the linear theory in Weinbaum et al. (2003).

Han, Yuefeng; Weinbaum, Sheldon; Spaan, Jos A. E.; Vink, Hans

2006-05-01

35

Comparative study of retinal nerve fiber layer thickness in normal eyes, ocular hypertensives, preperimetric glaucoma and glaucomatous subjects.  

PubMed

We assessed and compared the retinal nerve fiber layer (RNFL) thickness in normal eyes, ocular hypertensives, preperimetric glaucoma and glaucomatous subjects by means of optical coherence tomography in 449 eye. RNFL in glaucoma patients was significantly thinner than in normal subjects in every location evaluated. Use of optical coherence tomography detects glaucomatous RNFL losses in preperimetric glaucoma and can improve our ability to detect structural damage in clinical practice. PMID:19413224

Polo, Vicente; Larrosa, Jose M; Ferreras, Antonio; de la Casa, Jose M Martinez; Pablo, Luis E; Honrubia, Francisco M

2009-01-01

36

Bismuth-ring-doped fibres  

SciTech Connect

A new process for bismuth doping of optical fibres is proposed in which the dopant is introduced into a thin layer surrounding the fibre core. This enables bismuth stabilisation in the silica glass, with no limitations on the core composition. In particular, the GeO{sub 2} content of the fibre core in this study is 16 mol %. Spectroscopic characterisation of such fibres and optical gain measurements suggest that the proposed approach has considerable potential for laser applications. (optical fibres and fibreoptic sensors)

Zlenko, Aleksandr S; Dvoirin, Vladislav V; Bogatyrev, Vladimir A; Firstov, Sergei V [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Akhmetshin, Ural G [Tarusa Department of A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Tarusa, Kaluga region (Russian Federation)

2009-11-30

37

Agreement between Retinal Nerve Fiber Layer Measures from Spectralis and Cirrus Spectral Domain OCT  

PubMed Central

Purpose An assessment of the retinal nerve fiber layer (RNFL) provides important information on the health of the optic nerve. There are several non-invasive technologies, including spectral domain optical coherence tomography (SD-OCT), that can be used for in vivo imaging and quantification of the RNFL, but often there is disagreement in RNFL thickness between clinical instruments. The purpose of this study was to investigate the influence of scan centration, ocular magnification and segmentation on the degree of agreement of RNFL thickness measures by two SD-OCT instruments. Methods RNFL scans were acquired from forty-five normal eyes using two commercially available SD-OCT systems. Agreement between RNFL thickness measures was determined using each instrument's algorithm for segmentation and a custom algorithm for segmentation. The custom algorithm included ocular biometry measures to compute the transverse scaling for each eye. Major retinal vessels were identified and removed from RNFL measures in 1:1 scaled images. Transverse scaling was also used to compute the RNFL area for each scan. Results Instrument derived global RNFL thickness measured from the two instruments correlated well (R2 = 0.70, p<0.01), but with significant differences between instruments (mean of 6.7 µm; 95% limits of agreement of 16.0 µm to ?2.5 µm, ICC = 0.62). For recentered scans with custom RNFL segmentation, the mean difference was reduced to 0.1 µm (95% limits of agreement 6.1 µm to ?5.8 µm, ICC = 0.92). Global RNFL thickness was related to axial length (R2 = 0.24, p<0.01), while global RNFL area measures were not (R2 = 0.004, p = 0.66). Major retinal vasculature accounted for 11.3±1.6% (Cirrus) or 11.8±1.4% (Spectralis) of the RNFL thickness/area measures. Conclusions Sources of disagreement in RNFL measures between SD-OCT instruments can be attributed to the location of the scan path and differences in their retinal layer segmentation algorithms. In normal eyes, the major retinal vasculature accounts for a significant percentage of the RNFL and is similar between instruments. With incorporation of an individual's ocular biometry, RNFL area measures are independent of axial length, with either instrument.

Wheat, Joe L.; Rodriguez, Aldon; Tran, Victoria; Harwerth, Ronald S.

2011-01-01

38

Visual Field Defects and Normal Nerve Fiber Layer: May They Coexist in Primary Open-Angle Glaucoma?  

Microsoft Academic Search

The retinal nerve fiber layer (RNFL) is the anatomical structure most sensitive to glaucoma injury. Before a functional loss such as a visual field defect is displayed, a large number of nerve fibers can be damaged. However, there are glaucoma patients in which an apparently normal RNFL coexists with evident visual field defects. A total of 54 eyes affected with

Renato De Natale; Michele Marraffa; Roberta Morbio; Laura Tomazzoli; Luciano Bonomi

2000-01-01

39

Pattern of retinal nerve fiber layer damage in Korean eyes with normal-tension glaucoma and hemifield visual field defect  

Microsoft Academic Search

Purpose. To evaluate quantitatively the pattern of retinal nerve fiber layer (RNFL) damage in eyes with normal-tension glaucoma (NTG) with hemifield dominant visual field defects using scanning laser polarimetry. Methods. Prospectively, 40 consecutive eyes from 40 patients with NTG and hemifield defect based on the findings of examination using the Humphrey Field Analyzer underwent RNFL thickness measurements. Twenty normal eyes

Michael S. Kook; Sang-un Lee; Kyung-rim Sung; Hungwon Tchah; Soon-tae Kim; Kyung-rhee Kim; Weechang Kang

2002-01-01

40

Correlations Between Retinal Nerve Fiber Layer and Visual Field in Eyes with Non-Arteritic Anterior Ischemic Optic Neuropathy  

PubMed Central

Purpose To evaluate correlations between Retinal Nerve Fiber Layer (RNFL) thickness with visual field (VF) sensitivities in eyes with Non-artertic Anterior Ischemic Optic Neuropathy (NAION). Design case-control study. Methods This study was conducted in an academic, institutional setting. One eye from 21 NAION patients and 32 healthy participants were included in this prospective study. Humphrey Visual Field (HVF) sensitivities were obtained from standard achromatic HVF test (24-2 SITA). RNFL was measured with scanning laser polarimetry (GDx-VCC) and optical coherence tomographer (StratusOCT). Correlations were evaluated between RNFL and sensitivities from global, hemifields and regional locations of the VF pertinent to the RNFL distribution. 15 NAION eyes had an inferior altitudinal HVF defects and their global and regional RNFL was compared to that of control eyes. The main outcome measure was correlation between HVF sensitivities and RNFL. Results Correlations of global, hemifield and sectorial HVF sensitivities with RNFL were greater when RNFL was measured with StratusOCT than with GDx-VCC, except for nasal and infero-nasal sectors. RNFL thickness was significantly lower in the hemiretinas corresponding to the relative unaffected hemifield in eyes with altitudinal visual field defect compared to controls. Conclusions In patients with NAION, RNFL measured by StratusOCT provided better correlation to HVF changes than GDx-VCC did. Both instruments showed decreased RNFL in NAION eyes with altitudinal visual field defects compared to control eyes, demonstrating loss of RNFL even in sectors of the optic disc that corresponded to relatively unaffected hemifield, suggesting greater damaged beyond the extent estimated by visual field methods.

DeLeon-Ortega, Julio; Carroll, Kristin E.; Arthur, Stella N.; Girkin, Christopher A.

2007-01-01

41

The Effect of Various Factors on Variability of Retinal Nerve Fiber Layer Thickness Measurements Using Optical Coherence Tomography  

PubMed Central

Purpose To evaluate the effects of various factors on the variability of retinal nerve fiber layer (RNFL) thickness measurements using the Stratus optical coherence tomography (OCT) in normal and glaucomatous eyes. Methods Four hundred seventy-four subjects (103 normal eyes and 371 glaucomatous eyes) were scanned to determine the RNFL thickness measurements using the Stratus OCT. Measurements were obtained twice during the same day. The standard deviation (SD) was used to compare the variability in RNFL thickness measurements of the normal subjects to that of the glaucomatous patients. Multivariate regression analysis was used to evaluate which covariates were independent predictors of SD in overall mean RNFL thickness. Results The mean SD of all RNFL thickness measurements was larger in the glaucoma group except in one sector. In the multivariate regression analysis, the average signal strength (SS) and the relative SS change (difference in SS between initial and repeat scans, divided by initial SS) were independent predictors of the SD in the RNFL thickness measurements (partial R2 = 0.018, 0.013; p = 0.016, 0.040, respectively). Conclusions Glaucomatous eyes tend to be more variable than normal eyes in RNFL thickness measurement using the Straus OCT. The average SS and the relative SS changes appear to correlate with the variability in RNFL thickness measurement. Therefore, the results of the RNFL analysis should not be interpreted independently of these factors.

Youm, Dong Ju; Kim, Hyunjoong; Shim, Seong Hee; Jang, Hyo Ju; Kim, Joon Mo; Park, Ki Ho; Choi, Chul Young

2012-01-01

42

Microbuckle propagation in fibre composites  

Microsoft Academic Search

The propagation of a microbuckle in a unidirectional long fibre composite has been investigated by the finite element method. The tip region of the microbuckle is modelled using alternating layers of fibre and matrix, while the microbuckle at the macro scale is treated as a sliding mode II crack. By assuming that the composite deforms in accordance with a deformation

M. P. F. Sutcliffe; N. A. Fleck

1997-01-01

43

Property Optimisation in Fibre Metal Laminates  

Microsoft Academic Search

Fibre Metal Laminates (FMLs) are hybrid materials, which consist of thin metal sheets bonded together with alternating unidirectional fibre layers. This material concept has resulted in superior fatigue characteristics with respect to the metallic counterpart. Several static characteristics (specifically tension, shear, bearing, blunt and sharp notch behaviour) are however negatively influenced due to the fibre addition. This paper investigates the

R. van Rooijen; J. Sinke; T. J. De Vries; S. van der Zwaag

2004-01-01

44

Natural fibre reinforced sheet moulding compound  

Microsoft Academic Search

This paper describes a newly developed system, which enables utilisation of short flax fibres for SMC (Sheet Moulding Compound) production. It is shown that by using an evenly distributed layer of short dried flax fibres, after controlled impregnation and maturation, a homogeneous flow of the prepreg in the mould is obtained, and accordingly a flax fibre reinforced SMC can be

B van Voorn; H. H. G. Smit; R. J. Sinke; B de Klerk

2001-01-01

45

The attenuation of retinal nerve fiber layer thickness and cognitive deterioration  

PubMed Central

Thinner retinal nerve fiber layer (RNFL) has been reported in Alzheimer’s disease (AD) patient. However, whether changes in RNFL thickness can predict the cognitive deterioration remains unknown. We therefore set out a prospective clinical investigation to determine the potential association between the attenuation of RNFL thickness and the deterioration of cognitive function over a period of 25 months. We assessed cognitive function using the Repeatable Battery for the Assessment of Neuropsychological Status and measured RNFL thickness employing optical coherence tomography in 78 participants (mean age 72.31 ± 3.98 years, 52% men). The participants were categorized as stable participants whose cognitive status remained no change (N = 60) and converted participants whose cognitive status deteriorated (N = 18). We found that there was an association between the attenuation of superior quadrant RNFL thickness and the deterioration of cognitive function in the stable participants. In the converted participants, however, there was an inverse association between the reduction of inferior quadrant RNFL thickness and decline of cognitive functions [scores of list recall (R = -0.670, P = 0.002), adjusted (R = -0.493, P = 0.031)]. These data showed that less reduction in the inferior quadrant of RNFL thickness might indicate a higher risk for the patients to develop cognitive deterioration. These findings have established a system to embark a larger scale study to further test whether changes in RNFL thickness can serve as a biomarker of AD, and would lead to mechanistic studies to determine the cellular mechanisms of cognitive deterioration.

Shen, Yuan; Shi, Zhongyong; Jia, Renbao; Zhu, Yikang; Cheng, Yan; Feng, Wei; Li, Chunbo

2013-01-01

46

Retinal Nerve Fiber Layer Assessment: Area versus Thickness Measurements from Elliptical Scans Centered on the Optic Nerve  

PubMed Central

Purpose. An evaluation of the retinal nerve fiber layer (RNFL) provides important information on the health of the optic nerve. Standard measurements of the RNFL consider only thickness, but an accurate assessment should also consider axial length, size of the optic nerve head (ONH), blood vessel contribution, and distance of the scan from the ONH margin. In addition, although most primate ONHs are elliptical, the circular scan centered on the ONH is the mainstay in both clinical and research analyses. The purpose of this study was to evaluate thickness and area measures of RNFL cross sections when axial length and ONH shape are included. Methods. Circular, raster, and radial scans of left eye optic nerves were acquired from 40 normal rhesus monkeys (Macaca mulatta) using spectral domain optical coherence tomography. The disc margin was identified by manually selecting the RPE/Bruch's membrane opening and ONH border tissue. With a pixel-to-micrometer conversion computed from a three-surface schematic eye, RNFL scans were interpolated at 300 to 600 ?m (50-?m increments) from the edge of the ONH. The thickness and area of the RNFL at each distance were obtained by custom programs. Blood vessels in the RNFL were selected and removed from the overall RNFL measures. Results. The average RNFL thickness decreased systematically from 149 ± 12.0 ?m for scans 300 ?m from the disc margin to 113 ± 7.2 ?m at an eccentricity of 600 ?m (P < 0.05). In contrast, the cross-sectional areas of the RNFL did not vary with scan location from the disc margin (0.85 ± 0.07 mm2 at 300 ?m compared with 0.86 ± 0.06 mm2 at 600 ?m). Blood vessels accounted for 9.3% of total RNFL thickness or area, but varied with retinal location. On average, 17.6% of the superior and 14.2% of the inferior RNFL was vascular, whereas blood vessels accounted for only 2.3% of areas of the temporal and nasal RNFL regions. Conclusions. In nonhuman primates, with appropriate transverse scaling and ONH shape analysis, the cross-sectional area of the RNFL is independent of scan distance, up to 600 ?m from the rim margin, indicating that the axonal composition changes little over this range. The results suggest that, with incorporation of transverse scaling, the RNFL cross-sectional area, rather than RNFL thickness, provides an accurate assessment of the retinal ganglion cell axonal content within the eye.

Luo, Xunda; Wheat, Joe L.; Harwerth, Ronald S.

2011-01-01

47

No effect of short-term exposure to high-fibre diets on the gastrointestinal morphology of layer hens (Gallus gallus domesticus): body reserves are used to manage energy deficits in favour of phenotypic plasticity.  

PubMed

Summary Using layer hens, Gallus gallus domesticus, we compared the digestive capabilities of birds on a low-fibre diet (LF, 8.49% neutral detergent fibre; NDF), with those fed a high-fibre diet balanced for energy and protein to match the LF diet (high fibre balanced, HFB; NDF?=?15.61%) and those fed a high fibre unbalanced (HFU) diet (NDF?=?16.68%). The HFU diet had the lowest apparent dry matter (DM) metabolisability at 58.14?±?6.46%, followed by HFB, 65.87?±?3.50 and the LF diet, 70.49?±?7.07%. Despite significant differences between apparent DM metabolisabilities of LF and HFU diets, no morphometric changes in the gastrointestinal tract (GIT) of layer hens were observed (including crop, gizzard, proventriculus, liver, large intestine, paired caeca and small intestine). Conversely, body mass losses were recorded for animals on HFU diet, while those on the LF and HFB diets actually gained body mass over the 14-day trials. We suggest that the body mass losses seen in the animals fed HFU diets were attributed to losses in adipose tissue, but this was not quantified. Assuming body mass losses were mainly in adipose tissue, we propose that adipose may act to buffer environmental challenges like shortfalls in nutrient acquisition when dietary energy requirements are not met. Compared with smaller birds (e.g. quail), the larger body size of the layer hens may offer them a greater safety margin in terms of body energy reserves before changes in the GIT might be needed to redress energy deficits associated with hard-to-digest, high-fibre diets. PMID:22882770

Courtney Jones, S K; Cowieson, A J; Williamson, S A; Munn, A J

2012-08-01

48

Evaluation of Retinal Nerve Fiber Layer Thickness in Retinitis Pigmentosa Patients Using Spectral-Domain OCT  

PubMed Central

Purpose To measure the peripapillary retinal nerve fiber layer (RNFL) thickness using spectral-domain OCT (SD-OCT) in patients with retinitis pigmentosa. Methods Fifty eyes of 30 patients with retinitis pigmentosa underwent a complete ocular examination, including best-corrected visual acuity (BCVA) using a Snellen chart, slit-lamp biomicroscopic examination, and Goldmann applanation intraocular pressure (IOP) measurement. Dilated fundus examination was done by using both direct and indirect ophthalmoscopy. In addition, all patients underwent peripapillary RNFL thickness measurements by using an OPKO SD-OCT. Results The mean (±SD) age of the study cohort was 45.8 (16.3) years. Eighteen of the 50 eyes (36%) showed a thinning of the peripapillary RNFL in one or more quadrants and 21 of the 50 eyes (42%) showed a thickening of the peripapillary RNFL in one or more quadrants. Four eyes (8%) showed both thinning and thickening of the peripapillary RNFL thickness. The overall circumferential RNFL thickness of the 14 eyes that showed only thinning in at least one quadrant was 78.78 µm. For the 17 eyes that showed only thickening in at least one quadrant, the RNFL thickness was 119.69 µm. The values of the eyes with thinning and the eyes with thickening were significantly different from normal (t=6.31, p<0.01 for thickening; t=3.62, p<0.01 for thinning). Conclusion By using SD-OCT testing, we demonstrated in the current study that the peripapillary RNFL thickness in RP patients can be either decreased or increased as well as within normal limits. Assessment of the RNFL seems prudent in these patients, particularly for identifying notable degrees of RNFL thinning, in those being considered for future therapeutic trials.

Anastasakis, Anastasios; Genead, Mohamed A.; McAnany, J. Jason; Fishman, Gerald A.

2011-01-01

49

Localized wedge-shaped defects of retinal nerve fiber layer and disc hemorrhage in glaucoma 1 1 The authors have no proprietary interest in any aspect of this study  

Microsoft Academic Search

ObjectiveTo evaluate frequencies of localized wedge-shaped defects of the retinal nerve fiber layer (RNFL) in eyes with and without disc hemorrhage in normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG). This study also aims to define a topographic correlation between disc hemorrhage and localized RNFL defects in POAG.

Kazuhisa Sugiyama; Hideya Uchida; Goji Tomita; Yukihide Sato; Aiko Iwase; Yoshiaki Kitazawa

1999-01-01

50

Elastic fibres of the human ductus deferens.  

PubMed Central

The distribution of elastic fibres in the human ductus deferens from birth to senility was studied by light and electron microscopy. Elastic fibres are lacking in the ductus deferens in infants and children. In the adult ductus deferens, they form two layers in the lamina propria: (1) an inner layer of circumferentially oriented elastic fibres, and (2) an outer meshwork of elastic fibres. Elastic fibres are also present in the narrow intercellular spaces between the smooth muscle cells of the muscular coat, mainly in the inner muscular layer. A layer of elastic fibres surrounds the muscular coat. The ductus deferens of ageing subjects shows fragmentation and disorganisation of the elastic fibre layers of the lamina propria. Elastic fibres in the muscular coat are more abundant than in younger adults, forming larger bundles. Electron microscopy demonstrated the presence of immature elastic fibres at puberty as collections of microfibrils, some of them containing loci of amorphous substance (elastin). In the adult ductus most elastic fibres have a mature appearance. The amount of amorphous substance has increased and the number of microfibrils has decreased. Electron-dense inclusions are present within the amorphous substance. With advancing age the amorphous substance forms large, structureless masses showing abundant electron-dense inclusions and areas of rarefaction. A thin layer of microfibrils is present only at the periphery of the elastic fibres. Whether or not androgenic hormones are in any way involved in the formation of elastic fibres in the ductus deferens and testis is something which requires further study. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9

Paniagua, R; Regadera, J; Nistal, M; Santamaria, L

1983-01-01

51

The correlation between rat retinal nerve fiber layer thickness around optic disc by using optical coherence tomography and histological measurements  

PubMed Central

AIM To explore the correlation between the retinal nerve fiber layer (RNFL) thickness by using optical coherence tomography (OCT) and by histological measurements in normal adult rats and optic nerve transected rats. METHODS The RNFL thickness of 36 rats was scanned in a circle 3.46mm far from the optic disc by OCT. The two experimental groups were the normal group (n=20 rats) and the optic nerve transected group (n=16 rats). The latter group included 4 groups (n=4/group) surviving for 1 day, 3, 5 and 7 days. Then the RNFL thickness of the same retina area was also measured by NF-200 immunohistochemical staining method. Linear regression was used to analyze the correlation between the data obtained from these two methods. RESULTS The RNFL thickness of normal right eyes around optic disc by OCT was 72.35±5.71µm and that of the left eyes was 72.65±5.88µm (P=0.074). The RNFL thickness of the corresponding histological section by immunohistochemistry was 37.54±4.05µm (right eyes) and 37.38±4.23µm (left eyes) (P=0.059). There was a good correlation between the RNFL thickness measured by OCT and that measured by histology (R2=0.8131). After optic nerve transection, the trend of the RNFL thickness was thinner with the prolonged survival time. The correlation of the thickness detected by the above two methods was approximately (R2=0.8265). Value of the RNFL thickness in rats around optic disc measured by OCT was obviously higher than that measured by common histological measurement in normal adult rats and optic nerve transected rats. CONCLUSION The RNFL thickness measured by OCT has a strong correlation with that measured by histological method. Through OCT scanning, we found that the thickness of RNFL gradually becomes thinner in a time-dependent manner.

Huang, Ju-Fang; Yu, Hui-Min; Shang, Lei; Ma, Ruo-Fei; Cynthia, Ngobe Akume; Cao, Yan-Qun; Luo, Jia; Zeng, Le-Ping; Chen, Dan; Xiong, Kun

2013-01-01

52

Reflectance Speckle of Retinal Nerve Fiber Layer Reveals Axonal Activity  

PubMed Central

Purpose. This study investigated the retinal nerve fiber layer (RNFL) reflectance speckle and tested the hypothesis that temporal change of RNFL speckle reveals axonal dynamic activity. Methods. RNFL reflectance speckle of isolated rat retinas was studied with monochromatic illumination. A series of reflectance images was collected every 5 seconds for approximately 15 minutes. Correlation coefficients (CC) of selected areas between a reference and subsequent images were calculated and plotted as a function of the time intervals between images. An exponential function fit to the time course was used to evaluate temporal change of speckle pattern. To relate temporal change of speckle to axonal activity, in vitro living retina perfused at a normal (34°C) and a lower (24°C) temperature, paraformaldehyde-fixed retina, and retina treated with microtubule depolymerization were used. Results. RNFL reflectance was not uniform; rather nerve fiber bundles had a speckled texture that changed with time. In normally perfused retina, the time constant of the CC change was 0.56 ± 0.26 minutes. In retinas treated with lower temperature and microtubule depolymerization, the time constants increased by two to four times, indicating that the speckle pattern changed more slowly. The speckled texture in fixed retina was stationary. Conclusions. Fixation stops axonal activity; treatments with either lower temperature or microtubule depolymerization are known to decrease axonal transport. The results obtained in this study suggest that temporal change of RNFL speckle reveals structural change due to axonal activity. Assessment of RNFL reflectance speckle may offer a new means of evaluating axonal function.

Huang, Xiang-Run; Knighton, Robert W.; Zhou, Ye; Zhao, Xiao-Peng

2013-01-01

53

Retinal Nerve Fiber Layer Thickness. The Beijing Eye Study 2011  

PubMed Central

Purpose To measure retinal nerve fiber layer (RNFL) thickness in a population-based setting. Methods In the population-based Beijing Eye Study 2011 with 3468 individuals, RNFL thickness was measured in a subgroup of 1654 (47.7%) study participants by spectral domain optical coherence tomography (iVue SD-OCT). Results Mean RNFL thickness was significantly (P<0.001) higher in the inferior sector (131.4±20.6 µm) than the superior sector (126.1±19.1 µm), where it was higher than in the temporal sector (79.8±12.2 µm;P<0.001), where it was higher than in the nasal sector (75.1±12.6 µm;P<0.001). In multivariate analysis, mean global RNFL thickness (103.2±12.6 µm) increased significantly with younger age (standardized correlation coefficient beta:?0.30;P<0.001), larger neuroretinal rim area (beta:0.26;P<0.001), shorter axial length (beta:?0.21;P<0.001), thicker subfoveal choroidal thickness (beta:0.15;P<0.001), larger optic disc area (beta:0.10;P<0.001), less refractive lens power (beta:0.10;P<0.001), flatter anterior cornea (beta:0.07;P?=?0.01) and female gender (beta:0.05;P?=?0.03). In this population with an age of 50+ years, the age-related decline in RNFL thickness was 0.5 µm per year of life or 0.36% of an original RNFL thickness of 137 µm at baseline of the study at 50 years of age. Mean global RNFL thickness decreased by 2.4 µm for each mm enlargement of axial length. Conclusions The RNFL profile shows a double hump configuration with the thickest part in the inferior sector, followed by the superior sector, temporal sector and nasal sector. Factors influencing global RNFL thickness were younger age, larger neuroretinal rim, shorter axial length, thicker subfoveal choroid, larger optic disc, less refractive lens power, flatter anterior cornea and female gender. Beyond an age of 50+ years, RNFL decreased by about 0.3% per year of life at an age of 50+ years and by 2.4 µm per mm of axial elongation. These findings may be of interest for the knowledge of the normal anatomy of the eye and may be of help to diagnose diseases affecting the RNFL.

Wang, Ya Xing; Pan, Zhe; Zhao, Liang; You, Qi Sheng; Xu, Liang; Jonas, Jost B.

2013-01-01

54

Retinal Nerve Fiber Layer Images Captured by GDx-VCC in Early Diagnosis of Glaucoma  

Microsoft Academic Search

Objectives: To compare differences in retinal nerve fiber layer (RNFL) parameters between normal subjects and patients with various degrees of glaucoma, evaluate the sensitivity and specificity of GDx-VCC parameters, and determine the capability of GDx-VCC parameters and the most valuable indicators for the diagnosis of early glaucoma. Methods: GDx-VCC was used to measure RNFL in 80 patients with early glaucoma

Wang Zheng; Cui Baohua; Cao Qun; Qiao Zhi; Dai Hong

2008-01-01

55

Modeling the effects of aging on retinal ganglion cell density and nerve fiber layer thickness  

Microsoft Academic Search

Purpose  The effects of aging on retinal nerve fiber layer (RNFL) thickness should reflect the age-related losses in retinal ganglion\\u000a cells (RGCs), but published data suggest that the relative rate of thinning of RNFL thickness with age is less than predicted\\u000a by age-related losses of RGCs. Therefore, the present study was undertaken to reconcile the differences in age-dependency\\u000a on measures of

Ronald S. Harwerth; Joe L. Wheat

2008-01-01

56

Measurement of retinal nerve fiber layer thickness in optic atrophy eyes of patients with optic neuritis using optical coherence tomography  

Microsoft Academic Search

Objective  To measure the retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) in optic atrophy eyes of\\u000a patients with optic neuritis and investigate the correlation between the RNFL thickness and the visual function.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  To compare the RNFL thickness using StratusOCT, three groups of the subjects were enrolled, including 72 patients with optic\\u000a atrophy with definite demyelinating optic neuritis

Xin-Ling Wang; Tao Yu; De-Zhao Xia; Jin-Song Zhang; Qi-chang Yan; Ya-Hong Luo

2010-01-01

57

A Formula to Predict Spectral Domain Optical Coherence Tomography (OCT) Retinal Nerve Fiber Layer Measurements Based on Time Domain OCT Measurements  

PubMed Central

Purpose To establish and validate a formula to predict spectral domain (SD)-optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness from time domain (TD)-OCT RNFL measurements and other factors. Methods SD-OCT and TD-OCT scans were obtained on the same day from healthy participants and patients with glaucoma. Univariate and multivariate linear regression relationships were analyzed to convert average Stratus TD-OCT measurements to average Cirrus SD-OCT measurements. Additional baseline characteristics included age, sex, intraocular pressure, central corneal thickness, spherical equivalent, anterior chamber depth, optic disc area, visual field (VF) mean deviation, and pattern standard deviation. The formula was generated using a training set of 220 patients and then evaluated on a validation dataset of 105 patients. Results The training set included 71 healthy participants and 149 patients with glaucoma. The validation set included 27 healthy participants and 78 patients with glaucoma. Univariate analysis determined that TD-OCT RNFL thickness, age, optic disc area, VF mean deviation, and pattern standard deviation were significantly associated with SD-OCT RNFL thickness. Multivariate regression analysis using available variables yielded the following equation: SD-OCT RNFL = 0.746 × TD-OCT RNFL + 17.104 (determination coefficient [R2] = 0.879). In the validation sample, the multiple regression model explained 85.6% of the variance in the SD-OCT RNFL thickness. Conclusions The proposed formula based on TD-OCT RNFL thickness may be useful in predicting SD-OCT RNFL thickness. Other factors associated with SD-OCT RNFL thickness, such as age, disc area, and mean deviation, did not contribute to the accuracy of the final equation.

Lee, Kang Hoon; Kang, Min Gu; Lim, Hyunsun; Kim, Chan Yun

2012-01-01

58

Diagnostic accuracy of nerve fibre layer, macular thickness and optic disc measurements made with the RTVue-100 optical coherence tomograph to detect glaucoma  

PubMed Central

Purpose To evaluate the diagnostic accuracy of retinal nerve fibre layer thickness (RNFLT), ganglion cell complex (GCC), and optic disc measurements made with the RTVue-100 Fourier-domain optical coherence tomography (OCT) to detect glaucoma in a Caucasian referral population. Methods One randomly selected eye of 286 Caucasian patients (93 healthy, 36 ocular hypertensive, 46 preperimetric glaucoma, and 111 perimetric glaucoma eyes) was evaluated. Results Using the software-provided classification, for the total population sensitivity did not exceed 73.6% for the optic nerve head parameters, and 62.7% for the other parameters. Specificity was high (94.6–100%) for most RNFLT and GCC parameters, but low (72.0–76.3%) for the optic disc parameters. Positive predictive value varied between 98.1 and 100% for the main RNFLT parameters, 92.6 and 100% for the 16 RNFLT sectors, 92.4 and 99.0% for the GCC parameters, but did not exceed 86.3% for any of the optic disc parameters. Positive likelihood ratio (PLR) was higher than 10 for average, inferior and superior RNFLT (25.5 to infinite), 12 of the 16 RNFLT sectors (12.6 to infinite), and three of the four GCC parameters (40.0 to 48.6). No optic disc parameter had a PLR higher than 3.0. Conclusions RNFLT and GCC parameters of the RTVue-100 Fourier-domain OCT showed moderate sensitive but high specificity, positive predictive value and PLR for detection of glaucoma. The optic disc parameters had lower diagnostic accuracy than the RNFLT and GCC parameters.

Garas, A; Vargha, P; Hollo, G

2011-01-01

59

Cross-sectional texture of carbon fibres analysed by scanning microbeam X-ray diffraction  

Microsoft Academic Search

Scanning microbeam X-ray diffraction analysis of single carbon fibres allows the cross-sectional orientation distribution (texture) of the carbon layers to be determined, even when the fibre axis is oriented perpendicular to the X-ray beam (fibre geometry). The fibre is scanned across a microbeam with a diameter significantly smaller than the fibre diameter, and fibre diffraction patterns are recorded for every

Dieter Loidl; Martin Muller; Helga Lichtenegger; Herwig Peterlik; Erich Schmid

2001-01-01

60

The effect of excimer laser photorefractive keratectomy for myopia on nerve fiber layer thickness measurements as determined by scanning laser polarimetry 1 1 The authors have no proprietary interest in any product discussed in this article. The views and opinions expressed herein are those of the authors and are not to be construed as official views of the Department of the Navy, the Department of Defense, or of the United States Government. No commercial endorsement of any product by the United States Navy is intended or implied  

Microsoft Academic Search

ObjectiveScanning laser polarimetry measures the retardation of polarized laser light as it passes through the birefringent retinal nerve fiber layer (RNFL). Because retardation is directly proportional to the number of retinal nerve fibers, indirect measurements of the RNFL thickness are obtained. A fixed compensatory mechanism is used to correct for retardation attributed to birefringence in the cornea and anterior segment.

Neil T Choplin; Steven C Schallhorn

1999-01-01

61

The exploitation of thin film coatings for fibre sensors for the application of chemical sensing  

Microsoft Academic Search

We report on the use of thin film coatings, both single and multi-layered, deposited on the flat side of a lapped, D-shaped fibre to enhance the sensitivity of two kinds of surface plasmon resonance based optical fibre sensors. The first kind involves the use of a tilted Bragg grating inscribed within the fibre core, prior to fibre coating, while the

T. Allsop; R. Neal; K. Kalli; E. M. Davies; S. Rehman; R. R. J. Maier; J. Barton; J. D. Jones; D. J. Webb; I. Bennion

2009-01-01

62

A review: Fibre metal laminates, background, bonding types and applied test methods  

Microsoft Academic Search

During the past decades, increasing demand in aircraft industry for high-performance, lightweight structures have stimulated a strong trend towards the development of refined models for fibre-metal laminates (FMLs). Fibre metal laminates are hybrid composite materials built up from interlacing layers of thin metals and fibre reinforced adhesives. The most commercially available fibre metal laminates (FMLs) are ARALL (Aramid Reinforced Aluminium

Tamer Sinmazçelik; Egemen Avcu; Mustafa Özgür Bora; Onur Çoban

2011-01-01

63

Longitudinal Study of Vision and Retinal Nerve Fiber Layer Thickness in MS  

PubMed Central

Objective Cross-sectional studies of optical coherence tomography (OCT) show that retinal nerve fiber layer (RNFL) thickness is reduced in multiple sclerosis (MS) and correlates with visual function. We determined how longitudinal changes in RNFL thickness relate to visual loss. We also examined patterns of RNFL thinning over time in MS eyes with and without a prior history of acute optic neuritis (ON). Methods Patients underwent OCT measurement of RNFL thickness at baseline and at 6-month intervals during a mean follow-up of 18 months at three centers. Low-contrast letter acuity (2.5%, 1.25% contrast) and visual acuity (VA) were assessed. Results Among 299 patients (593 eyes) with ?6 months follow-up, eyes with visual loss showed greater RNFL thinning compared to eyes with stable vision (low-contrast acuity, 2.5%: p<0.001; VA: p=0.005). RNFL thinning increased over time, with average losses of 2.9 ?m at 2-3 years and 6.1 ?m at 3-4.5 years (p<0.001 vs. 0.5-1-year follow-up interval). These patterns were observed for eyes with or without prior history of ON. Proportions of eyes with RNFL loss greater than test-retest variability (?6.6 ?m) increased from 11% at 0-1 year to 44% at 3-4.5 years (p<0.001). Interpretation Progressive RNFL thinning occurs as a function of time in some patients with MS, even in the absence of ON, and is associated with clinically significant visual loss. These findings are consistent with sub-clinical axonal loss in the anterior visual pathway in MS and support the use of OCT and low-contrast acuity as methods to evaluate the effectiveness of putative neuroprotection protocols.

Talman, Lauren S.; Bisker, Esther R.; Sackel, David J.; Long, David A.; Galetta, Kristin M.; Ratchford, John N.; Lile, Deacon J.; Farrell, Sheena K.; Loguidice, Michael J.; Remington, Gina; Conger, Amy; Frohman, Teresa C.; Jacobs, Dina A.; Markowitz, Clyde E.; Cutter, Gary R.; Ying, Gui-Shuang; Dai, Yang; Maguire, Maureen G.; Galetta, Steven L.; Frohman, Elliot M.; Calabresi, Peter A.; Balcer, Laura J.

2010-01-01

64

Long-term retinal nerve fiber layer changes following nonarteritic anterior ischemic optic neuropathy  

PubMed Central

Background In cases of nonarteritic anterior ischemic optic neuropathy (NAION), retinal nerve fiber layer (RNFL) thickness changes have been described during the first 12 months following the acute event. The purpose of this study was to report on the long-term RNFL changes in these eyes beyond the first year following onset of NAION. Methods Fourteen eyes of 13 patients with NAION were analyzed in this retrospective observational case series study. Uninvolved eyes served as controls. All patients underwent a complete neuro-ophthalmological examination and repeat measurements of peripapillary RNFL thickness using Stratus optical coherence tomography. Results On optical coherence tomography scan performed on average 6 months following onset of NAION, the mean global RNFL thickness (59.8 ± 11.8 ?m) was significantly thinner (P < 0.001) compared with uninvolved eyes (95.1 ± 13.9 ?m). In a second optical coherence tomography scan performed on average 13 (range 12–23) months later, the mean global RNFL thickness (58.9 ± 6.5 ?m) was not significantly different (P = 0.702) from the first scan. Conclusion There appears to be no further RNFL loss beyond the first 6 months following an acute event of NAION.

Dotan, Gad; Goldstein, Michaella; Kesler, Anat; Skarf, Barry

2013-01-01

65

Attenuated Age-Related Thinning of Peripapillary Retinal Nerve Fiber Layer in Long Eyes  

PubMed Central

Purpose To assess the impact of axial length on the age-related peripapillary retinal nerve fiber layer (RNFL) thinning. Methods This cross-sectional observational comparative case series included 172 eyes from 172 healthy Korean subjects. Peripapillary RNFL thickness was measured using an Optic Disc Cube 200 × 200 scan of spectral domain Cirrus HD OCT and the axial length was measured using IOL Master Advanced Technology. In age groups based on decade, the normal ranges of peripapillary RNFL thickness for average, quadrant, and clock-hour sectors were determined with 95% confidence intervals. After dividing the eyes into two groups according to axial length (cut-off, 24.50 mm), the degrees of age-related RNFL thinning were compared. Results Among the eyes included in the study, 53 (30.81%) were considered to be long eyes (axial length, 25.04 ± 0.48 µm) and 119 (69.19%) were short-to-normal length eyes (axial length, 23.57 ± 0.60 µm). The decrease in average RNFL thickness with age was less in long eyes (negative slope, -0.12 µm/yr) than in short-to-normal length eyes (negative slope, -0.32 µm/yr) (p < 0.001). Conclusions Age-related thinning of peripapillary RNFL thickness is attenuated in long eyes compared to short-to-normal length eyes.

Kim, Eun-Ji; Hong, Samin; Kim, Chan Yun; Lee, Eun Suk

2011-01-01

66

Multimaterial piezoelectric fibres  

Microsoft Academic Search

Fibre materials span a broad range of applications ranging from simple textile yarns to complex modern fibre-optic communication systems. Throughout their history, a key premise has remained essentially unchanged: fibres are static devices, incapable of controllably changing their properties over a wide range of frequencies. A number of approaches to realizing time-dependent variations in fibres have emerged, including refractive index

S. Egusa; Z. Wang; N. Chocat; Z. M. Ruff; A. M. Stolyarov; D. Shemuly; F. Sorin; P. T. Rakich; J. D. Joannopoulos; Y. Fink

2010-01-01

67

Retinal nerve fiber layer and macular inner retina measurements by spectral domain optical coherence tomograph in Indian eyes with early glaucoma  

PubMed Central

Purpose To compare the diagnostic abilities of peripapillary retinal nerve fiber layer (RNFL) and macular inner retina (MIR) measurements by spectral domain optical coherence tomography (SD–OCT) in Indian eyes early glaucoma. Methods In an observational, cross-sectional study, 125 eyes of 64 normal subjects and 91 eyes of 59 early glaucoma patients underwent RNFL and MIR imaging with SD–OCT. Glaucomatous eyes had characteristic optic nerve and RNFL abnormalities and correlating visual field defects and a mean deviation of better than or equal to -6?dB on standard automated perimetry. Areas under the receiver operating characteristic curves (AUC), sensitivities at a fixed specificity and likelihood ratios (LRs) were estimated for all RNFL and MIR parameters. Results The AUCs for the RNFL parameters ranged from 0.537 for the temporal quadrant thickness to 0.821 for the inferior quadrant RNFL thickness. AUCs for the MIR parameters ranged from 0.603 for the superior minus inferior MIR thickness average to 0.908 for ganglion cell complex focal loss volume (GCC–FLV). AUC for the best MIR parameter (GCC–FLV) was significantly better (P<0.001) than that of the best RNFL parameter (inferior quadrant thickness). The sensitivities of these parameters at high specificity of 95%, however, were comparable (52.7% vs58.2%). Evaluation of the LRs showed that outside normal limits results of most of the RNFL and MIR parameters were associated with large effects on the post-test probability of disease. Conclusion MIR parameters with RTVue SD–OCT were as good as the RNFL parameters to detect early glaucoma.

Rao, H L; Babu, J G; Addepalli, U K; Senthil, S; Garudadri, C S

2012-01-01

68

Fibre-reinforced materials.  

PubMed

This paper considers the role of fibres in the reinforcement of composite materials, and the significance of the form the fibre takes and the material from which it is made. The current dental applications of fibre reinforcement, including dental cements and splints, fibres made into structures for use in composites, denture bases and the contemporary use of fibres in fixed partial dentures, are reviewed. Their role in biomedical implants is surveyed and their future forecast. PMID:11218597

Brown, D

2000-11-01

69

Imaging of the optic disc and retinal nerve fiber layer: the effects of age, optic disc area, refractive error, and gender  

NASA Astrophysics Data System (ADS)

We cross-sectionally examined the relationship between age, optic disc area, refraction, and gender and optic disc topography and retinal nerve fiber layer (RNFL) measurements, using optical imaging techniques. One eye from each of 155 Caucasian subjects (age range 23.0-80.8 y) without ocular pathology was included. Measurements were obtained by using the Heidelberg Retina Tomography (HRT), the GDx Nerve Fiber Analyzer, and the Optical Coherence Tomograph (OCT). The effects of age were small (R2<17%) and were limited to specific HRT, GDx, and OCT parameters. Disc area was significantly associated with most HRT parameters and isolated GDx and OCT parameters. Refraction and gender were not significantly associated with any optic disc or RNFL parameters. Although effects of age on the optic disc and RNFL are small, they should be considered in monitoring ocular disease. Optic disc area should be considered when cross-sectionally evaluating disc topography and, to a lesser extent, RNFL thickness.

Bowd, Christopher; Zangwill, Linda M.; Blumenthal, Eytan Z.; Vasile, Cristiana; Boehm, Andreas G.; Gokhale, Parag A.; Mohammadi, Kourosh; Amini, Payam; Sankary, Timothy M.; Weinreb, Robert N.

2002-01-01

70

Inter-Device Agreement of Retinal Nerve Fiber Layer Thickness Measurements Using Spectral Domain Cirrus HD OCT  

PubMed Central

Purpose To assess the inter-device agreement of peripapillary retinal nerve fiber layer (RNFL) thickness measurements by 2 spectral domain Cirrus HD optical coherence tomography (OCT) devices in healthy Korean subjects. Methods Eleven eyes of 11 healthy volunteers were enrolled in the present study. Each eye was scanned with the Optic Disc Cube 200 × 200 scan of 2 Cirrus HD OCT devices for peripapillary RNFL thickness calculation. The inter-device agreements of the 2 Cirrus HD OCTs for average, quadrant, and clock-hour RNFL thickness values were determined with Wilcoxon signed rank test, Friedman test, Cronbach's alpha (?), intraclass correlation coefficient (ICC), coefficient of variation (COV), and Bland-Altman plot. Results The mean age of the participants was 25.82 ± 3.28 years and all had a 0.00 logarithm of the minimum angle of resolution of best-corrected visual acuity. The signal strengths of scans from the 2 Cirrus HD OCT were not significantly different (p = 0.317). The inter-device agreement of average RNFL thickness was excellent (?, 0.940; ICC, 0.945; COV, 2.45 ± 1.52%). However, the agreement of nasal quadrant RNFL thickness was not very good (?, 0.715; ICC, 0.716; COV, 5.72 ± 4.64%). Additionally, on the Bland-Atman plot, the extent of agreement of the 2 Cirrus HD OCTs for RNFL thickness was variable according to scanned sectors. Conclusions The inter-device agreement of 2 spectral domain Cirrus HD OCT devices for peripapillary RNFL thickness measurements was generally excellent but variable according to the scanned area. Thus, physicians should consider this fact before judging a change of RNFL thicknesses if they were measured by different OCT devices.

Hong, Samin; Kim, Yeongjun; Shim, Jongwoo; Kim, Chan Yun

2011-01-01

71

Retinal nerve fiber layer thickness and cognitive ability in older people: the Lothian Birth Cohort 1936 study  

PubMed Central

Background This study aims to examine the relationship between the retinal nerve fiber layer (RNFL) thickness as measured by optical coherence tomography (OCT) and lifetime cognitive change in healthy older people. Methods In a narrow-age sample population from the Lothian Birth Cohort 1936 who were all aged approximately 72 years when tested, participants underwent RNFL measurements using OCT. General linear modeling was used to calculate the effect of RNFL thickness on three domains; general cognitive ability (g-factor), general processing speed (g-speed) and general memory ability (g-memory) using age at time of assessment and gender as co-variates. Results Of 105 participants, 96 completed OCT scans that were of suitable quality for assessment were analyzed. Using age and gender as covariates, we found only one significant association, between the inferior area RNFL thickness and g-speed (p?=?0.049, ?2?=?0.045). Interestingly, when we included age 11 IQ as a covariate in addition to age and gender, there were several statistically significant associations (p?=?0.029 to 0.048, ?2?=?0.00 to 0.059) in a negative direction; decreasing scores on measures of g-factor and g-speed were associated with increasing RNFL thickness (r?=??0.229 to ?0.243, p?RNFL thickness and g-memory ability. When we considered the number of years of education as a covariate, we found no significant associations between the RNFL thickness and cognitive scores. Conclusions In a community dwelling cohort of healthy older people, increased RNFL thickness appeared to be associated with lower general processing speed and lower general cognitive ability when age 11 IQ scores were included as a covariate.

2013-01-01

72

Correlation between peripapillary retinal nerve fiber layer thickness and fundus autofluorescence in primary open-angle glaucoma  

PubMed Central

Purpose To investigate the relationship between retinal nerve fiber layer (RNFL) thickness and retinal pigment epithelium alterations in patients with advanced glaucomatous visual field defects. Methods A consecutive, prospective series of 82 study eyes with primary open-angle glaucoma and advanced glaucomatous visual field defects were included in this study. All study participants underwent a full ophthalmic examination followed by visual field testing with standard automated perimetry as well as spectral-domain optical coherence tomography (SD-OCT) for peripapillary RNFL thickness and Optos wide-field fundus autofluorescence (FAF) images. A pattern grid with corresponding locations between functional visual field sectors and structural peripapillary RNFL thickness was aligned to the FAF images at corresponding location. Mean FAF intensity (range: 0 = black and 255 = white) of each evaluated sector (superotemporal, temporal, inferotemporal, inferonasal, nasal, superonasal) was correlated with the corresponding peripapillary RNFL thickness obtained with SD-OCT. Results Correlation analyses between sectoral RNFL thickness and standardized FAF intensity in the corresponding topographic retina segments revealed partly significant correlations with correlation coefficients ranging between 0.004 and 0.376 and were statistically significant in the temporal inferior central field (r = 0.324, P = 0.036) and the nasal field (r = 0.376, P = 0.014). Conclusion Retinal pigment epithelium abnormalities correlate with corresponding peripapillary RNFL damage, especially in the temporal inferior sector of patients with advanced glaucomatous visual field defects. A further evaluation of FAF as a potential predictive parameter for glaucomatous damage is necessary.

Reznicek, Lukas; Seidensticker, Florian; Mann, Thomas; Hubert, Irene; Buerger, Alexandra; Haritoglou, Christos; Neubauer, Aljoscha S; Kampik, Anselm; Hirneiss, Christoph; Kernt, Marcus

2013-01-01

73

Surface nucleated growth of dipeptide fibres.  

PubMed

We report the surface nucleated growth of self-assembled dipeptide films. The seeding-layer was a thin dipeptide film with a globular structure. Placing the seeding-layer in contact with dipeptide led to growth of fibres overnight. Active enzymes were incorporated into the gel by adding them to the growth solution. PMID:23955276

Johnson, Eleanor K; Chen, Lin; Kubiak, Peter S; McDonald, Shane F; Adams, Dave J; Cameron, Petra J

2013-10-01

74

Opening up optical fibres.  

PubMed

A unique optical fibre design is presented in this work: a laterally accessible microstructured optical fibre, in which one of the cladding holes is open to the surrounding environment and the waveguide core exposed over long lengths of fibre. Such a fibre offers the opportunity of real-time chemical sensing and biosensing not previously possible with conventional microstructured optical fibres, as well as the ability to functionalize the core of the fibre without interference from the cladding. The fabrication of such a fibre using PMMA is presented, as well as experimental results demonstrating the use of the fibre as a evanescent wave absorption spectroscopy pH sensor using the indicator Bromothymol Blue. PMID:19547546

Cox, Felicity M; Lwin, Richard; Large, Maryanne C J; Cordeiro, Cristiano M B

2007-09-17

75

Polymer optical fibres: conventional and microstructured fibres  

NASA Astrophysics Data System (ADS)

Polymer optical fibres (POF) have historically focused on applications in data transmission over short distances, using highly multimode step-index or graded-index fibre designs. This paper will focus on a qualitatively different type of polymer fibres - microstructured polymer optical fibres (mPOF) - which allow a wider variety of fibre designs and optical properties to be achieved. Fibres with similar properties to conventional step- and graded-index POF can be made for data transmission applications, as well as single-mode fibres which can be used for grating inscription and gratingbased sensing. The use of microstructures can also be extended to longer wavelengths for the transmission of THz radiation, and both solid-core and hollow-core mPOF-based THz waveguides have been demonstrated. Finally, the development and extension of mPOF to form metal-dielectric structures for the manufacture of metamaterials using fibre-drawing methods will be discussed. Such drawn-metamaterials with electric and magnetic responses at THz frequencies have been demonstrated.

Argyros, Alexander; Leon-Saval, Sergio G.; Lwin, Richard; Provo, Richard; Murdoch, Stuart G.; Harvey, John D.; Anthony, Jessienta; Leonhardt, Rainer; Tuniz, Alessandro; Kuhlmey, Boris T.; Fleming, Simon C.

2012-02-01

76

CW bismuth fibre laser  

Microsoft Academic Search

A new fibre laser based on a bismuth-doped aluminosilicate glass fibre is proposed and fabricated. CW lasing is obtained in the spectral region between 1150 and 1300 nm. The fibres are fabricated by the method of modified chemical vapour deposition. Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Abstract Text

Evgenii M. Dianov; V. V. Dvoyrin; V. M. Mashinsky; A. A. Umnikov; M. V. Yashkov; A. N. Gur'yanov

2005-01-01

77

Photonic crystal fibres  

Microsoft Academic Search

Photonic crystal fibres have wavelength-scale morphological microstructure running down their length. This structure enables light to be controlled within the fibre in ways not previously possible or even imaginable. Our understanding of what an optical fibre is and what it does is changing because of the development of this new technology, and a broad range of applications based on these

Jonathan C. Knight

2003-01-01

78

Fibre-reinforced intermetallic compounds by physical vapour deposition  

Microsoft Academic Search

This paper describes work on SiC fibre-reinforced ?-Tial and MoSi2 intermetallic matrix composites (IMCs). Electron beam evaporation and vapour mixing were used to matrix-coat SiC fibre with a thick layer of intermetallic compound, and these coated fibres were successfully fabricated into IMCs. Intermetallic compounds have attractive properties for high-temperature structural applications and have been the subject of much research effort

Miriam Wood; Malcolm Ward-Close

1995-01-01

79

Fourier domain OCT measurement of macular, macular ganglion cell complex, and peripapillary RNFL thickness in glaucomatous Chinese eyes.  

PubMed

Purpose. To evaluate and compare the glaucoma discrimination ability of macula, macular ganglion cell complex (mGCC), and peripapillary nerve fiber layer (ppNFL) thickness in Chinese patients using Fourier-domain optical coherence tomography (FD-OCT). Methods. A total of 64 normal subjects (N), 47 glaucoma suspects (GS), and 48 glaucoma patients (G) were enrolled in the study. The thickness of mGCC, ppNFL, and total macula were measured using RTVue-100 FD-OCT (software version: 4.0.7.5; Optovue). The GCC and ONH protocols were used for obtaining images in all subjects. For each binocular subject, one eye was chosen randomly for analysis. Results. The average thicknesses of macular, mGCC, and ppNFL in normal eyes were significantly different from those in GS or G eyes (p<0.001). The mGCC thickness correlated well with ppNFL thickness (correlation coefficients for N, GS, and G eyes are 0.397 [p=0.001], 0.822 [p<0.0001], and 0.865 [p<0.0001]). Areas under receiver operating characteristic curve of macular, mGCC, and ppNFL thickness are 0.940 (p<0.0001), 0.998 (p<0.0001), and 0.977 (p<0.0001), discriminating G from N eyes. There was no significant difference comparing the discriminating powers of NFL, GCC, and macular thickness. Conclusions. The mGCC measurements provide another measurement of neural loss in glaucoma, and may serve as a promising parameter for ppNFL thickness in the clinical assessment of glaucoma. For glaucomatous eyes, mGCC and ppNFL thicknesses performed better discriminating abilities compared with macular thickness. PMID:22467590

Chen, Junyi; Huang, Haili; Wang, Min; Sun, Xinghuai; Qian, Shaohong

2012-03-20

80

Influence of Axial Length on Peripapillary Retinal Nerve Fiber Layer Thickness in Children: A Study by RTVue Spectral-Domain Optical Coherence Tomography.  

PubMed

Abstract Purpose: To evaluate the influence of axial length on peripapillary retinal nerve fiber layer (RNFL) thickness in myopic, hyperopic and emmetropic children eyes by RTVue optical coherence tomography (OCT). Methods: One hundred twenty eyes of 120 children including 40 myopic, 40 emmetropic and 40 hyperopic eyes were enrolled in the study. Peripapillary RNFL thickness measurements were performed using spectral-domain RTVue OCT (Optovue, Fremont, CA). RNFL thickness parameters were obtained from all octametric sections: upper temporal (TU), superotemporal (ST), superonasal (SN), upper nasal (NU), lower nasal (NL), inferonasal (IN), inferotemporal (IT) and lower temporal (TL). Spherical equivalent refractive error was determined via cycloplegic auto-refraction (Topcon, Tokyo, Japan). The axial length was measured using IOLMaster (Carl Zeiss MEDITEC). Littmann formula was used for correction of axial length-related ocular magnification effect. Results: Peripapillary RNFL thicknesses were significantly different among the three groups in all sectors except for NU and IT sectors. RNFL thicknesses in all sectors except for TU and TL sectors had significant negative correlations with axial length. However, these differences (excluding TU and TL sectors) and correlations disappeared after correction of magnification effect. Conclusion: In conclusion, axial length influences peripapillary RNFL thickness as measured by RTVue OCT. However, this appears to be due to the ocular magnification effects associated with axial length and can be corrected for with the application of the Littman formula. PMID:23972028

Aykut, Veysel; Oner, Veysi; Ta?, Mehmet; I?can, Yalç?n; A?açhan, Ahmet

2013-08-23

81

Comparison between laminated and integrated glass fibre reinforced plastics  

Microsoft Academic Search

Glass fibre reinforced honeycomb-like cores (I beam and T beam) with laminated and integrated structures were processed. They were tested for strength, and various analyses were carried out. Conventional glass fibre reinforced plastics are obtained by laminating two-dimensional fabrics with added resin. The material is liable to be broken or peeled apart between adjacent layers under repeated imposition of stress

Huang Gu

2000-01-01

82

Fibre optics: Forty years later  

SciTech Connect

This paper presents a brief overview of the state of the art in fibre optics and its main applications: optical fibre communications, fibre lasers and fibre sensors for various physical property measurements. The future of fibre optics and the status of this important area of the modern technology in Russia are discussed. (fiber optics)

Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2010-01-31

83

Microstructure and micromechanics of the interface in carbon fibre reinforced Pyrex glass  

Microsoft Academic Search

Detailed microstructural studies have been carried out on composites consisting of Pyrex glass reinforced with carbon fibres. Analysis of the fibre-matrix interface showed that some reaction had taken place during fabrication of the composite and that a carbide or oxycarbide layer had formed between the glass and the carbon fibre. The measured interlaminar shear strength of the composite indicated that

S. M. Bleay; V. D. Scott

1991-01-01

84

Structure reorganization during the rheological characterization of continuous fibre-reinforced composites in plane shear  

Microsoft Academic Search

An experimental study is made of the flow of a continuous fibre-reinforced laminate subject to plane shear. An apparatus has been constructed in which a plate can be withdrawn from a composite comprising of layers of aligned fibres set within a resin. Experiments are performed on a ‘model’ composite consisting of nylon fibres in a Newtonian matrix. Measurements of the

J. A. Goshawk; R. S. Jones

1996-01-01

85

Optical Coherence Tomography Study of Peripapillary Retinal Nerve Fiber Layer and Choroidal Thickness in Eyes With Tilted Optic Disc.  

PubMed

PURPOSE:: The tilted optic disc is associated with peripapillary choroidal and retinal nerve fiber layer (RNFL) changes as well as visual field defects, often leading to diagnostic difficulties due to similarities with glaucomatous discs. We studied the peripapillary RNFL of the tilted optic disc by comparing values obtained with spectral-domain (SD) and time-domain (TD) optical coherence tomography (OCT) in order to identify characteristic RNFL patterns verified by both OCT devices, and also to determine whether SD-OCT offers any diagnostic advantage over TD-OCT. METHODS:: Prospective case-control study of 16 individuals with tilted optic discs (27 eyes) and an age-matched control group (10 individuals, 20 eyes). Each case was subjected to ophthalmological examination and automated perimetry. Tilt orientation was classified based on observation of optic disc photographs, and angle of disc torsion was calculated with image processing software. RNFL measurements were obtained with TD-OCT and SD-OCT. Peripapillary choroid thickness was measured with SD-OCT. The findings were related with optic disc morphology and automated perimetry results. RESULTS:: Stratus OCT results showed significantly lower superior RNFL (P<0.001) on the tilted group, whereas Spectralis indicated significantly lower superotemporal (P<0.001), superonasal (P=0.001), temporal (P=0.01), and global (P=0.01) RNFL on the tilted disc group. A significant correspondence was found between elevated disc rim and location of RNFL defect on the Spectralis (P=0.004). On the tilted group, peripapillary choroidal thickness was significantly thicker adjacent to the elevated rim (P<0.001). No correspondence was found between tilt orientation, peripapillary RNFL, or choroidal thickness and location of perimetric defects. CONCLUSIONS:: Our results provide a clinical characterization of the main tilted disc morphologies and are valuable for correctly differentiating a tilted disc from a myopic glaucomatous disc. RNFL assessment by Spectralis OCT seems to be more susceptible to altered disc morphologies. The peripapillary RNFL changes found on titled disc cases could not predict the location of visual field defects. PMID:23429636

Brito, Pedro N; Vieira, Marco P; Falcão, Manuel S; Faria, Olinda S; Falcão-Reis, Fernando

2013-02-19

86

Effect of Media Opacity on Retinal Nerve Fiber Layer Thickness Measurements by Optical Coherence Tomography  

PubMed Central

Purpose To assess the effect of ocular media opacity on retinal nerve fiber layer (RNFL) thickness measurements by optical coherence tomography (OCT). Methods In this prospective, non-randomized clinical study, ocular examinations and OCT measurements were performed on 77 cataract patients, 80 laser refractive surgery patients and 90 patients whose signal strength on OCT was different on two consecutive measurements. None of the eyes had preexisting retinal or optic nerve pathology, including glaucoma. Cataracts were classified according to the Lens Opacity Classification System III (LOCS III). All eyes were scanned with the Stratus OCT using the Fast RNFL program before and three months after surgery. Internal fixation was used during scanning and all eyes underwent circular scans around the optic disc with a diameter of 3.4 mm. Results Average RNFL thickness, quadrant thickness and signal strength significantly increased after cataract surgery (P<0.05). Cortical and posterior subcapsular cataracts, but not nuclear cataracts, had a significant influence on RNFL thickness measurements (P<0.05). There was no significant difference between OCT parameters before and after laser refractive surgery. In eyes for which different signal strengths were observed, significantly larger RNFL thickness values were obtained on scans with higher signal strengths. Conclusion OCT parameters are affected by ocular media opacity because of changes in signal strength; cortical cataracts have the most significant effect followed by posterior subcapsular opacities. Laser refractive procedures do not seem to affect OCT parameters significantly.

Lee, Dae Woong; Kim, Joon Mo; Park, Ki Ho; Choi, Chul Young; Cho, Jung Gon

2010-01-01

87

Interpretation of the potential fields generated in the cerebellar cortex by a mossy fibre volley  

Microsoft Academic Search

1.Potential fields and unitary spikes in the cat cerebellar cortex were generated specifically by mossy fibre volleys and recorded by means of microelectrodes. The mossy fibres were excited by trans-folial (T. F.) stimulation which was compared with juxtafastigial (J.F.) stimulation. Both were conditioned by local stimuli of parallel fibres.2.In the granular layer, an incoming mossy fibre volley evoked a small

J. C. Eccles; K. Sasaki; P. Strata

1967-01-01

88

Muscle fibre types and metabolism in post-larval and adult stages of notothenioid fish  

Microsoft Academic Search

A histochemical study was carried out on muscle fibre types in the myotomes of post-larval and adult stages of seven species of notothenioid fish. There was little interspecific variation in the distribution of muscle fibre types in post-larvae. Slow fibres (diameter range 15–60 µm) which stained darkly for succinic dehydrogenase activity (SDHase) formed a superficial layer 1–2 fibres thick around

J. F. Dunn; S. D. Archer; I. A. Johnston

1989-01-01

89

The Relationship between Retinal Ganglion Cell Axon Constituents and Retinal Nerve Fiber Layer Birefringence in the Primate  

PubMed Central

Purpose To determine the degree of correlation between spatial characteristics of the retinal nerve fiber layer (RNFL) birefringence (?nRNFL) surrounding the optic nerve head (ONH) with the corresponding anatomy of retinal ganglion cell (RGC) axons and their respective organelles. Methods RNFL phase retardation per unit depth (PR/UD, proportional to ?nRNFL) was measured in two cynomolgus monkeys using enhanced polarization-sensitive optical coherence tomography (EPS-OCT). The monkeys were perfused with glutaraldehyde and eyes were enucleated and prepared for transmission electron microscopy (TEM) histological analysis. Morphological measurements from TEM images were used to estimate values of neurotubule density (?RNFL), axoplasmic area (Ax) mode, axon area (Aa) mode, slope (u) of neurotubule number versus axoplasmic area [neurotubule packing density], fractional area of axoplasm in the nerve fiber bundle (f), mitochondrial fractional area in the nerve fiber bundle (xm), mitochondriated axon profile fraction (mp), and length of axonal membrane profiles per unit nerve fiber bundle area (Lam/Ab). Registered PR/UD and morphological parameters from corresponding angular sections were then correlated using Pearson’s correlation and multi-level models. Results In one eye, there was a statistically significant correlation between PR/UD and ?RNFL (r = 0.67, P =0.005) and between PR/UD and neurotubule packing density (r = 0.70, P = 0.002). Correlation coefficients of r = 0.81 (P=0.01) and r = 0.50 (P = 0.05) were observed between PR/UD and (Ax) mode for each respective subject. Conclusion Neurotubules are the primary source of birefringence in the RNFL of the primate retina.

Pocock, Ginger M.; Aranibar, Roberto G.; Kemp, Nate J.; Specht, Charles S.; Markey, Mia K.; Rylander, H.G.

2009-01-01

90

Influence of optic disc size on the diagnostic performance of macular ganglion cell complex and peripapillary retinal nerve fiber layer analyses in glaucoma  

PubMed Central

Aim To evaluate the influence of optic disc size on the diagnostic accuracy of macular ganglion cell complex (GCC) and conventional peripapillary retinal nerve fiber layer (pRNFL) analyses provided by spectral domain optical coherence tomography (SD-OCT) in glaucoma. Methods Eighty-two glaucoma patients and 30 healthy subjects were included. All patients underwent GCC (7 × 7 mm macular grid, consisting of RNFL, ganglion cell and inner plexiform layers) and pRNFL thickness measurement (3.45 mm circular scan) by SD-OCT. One eye was randomly selected for analysis. Initially, receiver operating characteristic (ROC) curves were generated for different GCC and pRNFL parameters. The effect of disc area on the diagnostic accuracy of these parameters was evaluated using a logistic ROC regression model. Subsequently, 1.5, 2.0, and 2.5 mm2 disc sizes were arbitrarily chosen (based on data distribution) and the predicted areas under the ROC curves (AUCs) and sensitivities were compared at fixed specificities for each. Results Average mean deviation index for glaucomatous eyes was ?5.3 ± 5.2 dB. Similar AUCs were found for the best pRNFL (average thickness = 0.872) and GCC parameters (average thickness = 0.824; P = 0.19). The coefficient representing disc area in the ROC regression model was not statistically significant for average pRNFL thickness (?0.176) or average GCC thickness (0.088; P ? 0.56). AUCs for fixed disc areas (1.5, 2.0, and 2.5 mm2) were 0.904, 0.891, and 0.875 for average pRNFL thickness and 0.834, 0.842, and 0.851 for average GCC thickness, respectively. The highest sensitivities – at 80% specificity for average pRNFL (84.5%) and GCC thicknesses (74.5%) – were found with disc sizes fixed at 1.5 mm2 and 2.5 mm2. Conclusion Diagnostic accuracy was similar between pRNFL and GCC thickness parameters. Although not statistically significant, there was a trend for a better diagnostic accuracy of pRNFL thickness measurement in cases of smaller discs. For GCC analysis, an inverse effect was observed.

Cordeiro, Daniela Valenca; Lima, Veronica Castro; Castro, Dinorah P; Castro, Leonardo C; Pacheco, Maria Angelica; Lee, Jae Min; Dimantas, Marcelo I; Prata, Tiago Santos

2011-01-01

91

Ophthalmoscopic Assessment of the Retinal Nerve Fiber Layer. The Beijing Eye Study  

PubMed Central

Purpose To examine the retinal nerve fiber layer (RNFL) ophthalmoscopically, to search for localized RNFL defects, and to assess factors associated with RNFL visibility in a population-based setting. Methods The population-based cross-sectional Beijing Eye Study 2006 included 3251 subjects. Using color fundus photographs, RNFL visibility was assessed in grades from 0 to 8 in 8 fundus sectors. Localized RNFL defects were defined as wedge-shaped defects running towards the optic disc. Results After exclusion of subjects with optic media opacities, 2602 subjects (mean age:58.1±9.0 years) were included. RNFL visibility score was highest (P<0.001) in the temporal inferior region, followed by the temporal superior region, nasal superior region, and nasal inferior region. In multivariate analysis, higher RNFL visibility score was associated with younger age (P<0.001;standardized coefficient beta:?0.44;regression coefficient B: ?0.22; 95%CI: ?0.24, ?0.20), female gender (P<0.001;beta:0.11;B:1.00;95%CI:0.67,1.32), higher blood concentration of low-density lipoproteins (P?=?0.002;beta:0.07;B:0.34;95%CI:0.13,0.56), absence of dyslipidemia (P?=?0.001;beta: ?0.07;B: ?0.58;95%CI: ?0.93, ?0.24), lower blood glucose concentration (P?=?0.006;beta: ?0.05;B: ?0.14;95%CI: ?0.24, ?0.04), hyperopic refractive error (P<0.001;beta:0.15;B:0.45;95%CI:0.34,0.56), smaller optic disc size (P<0.001;beta: ?0.08; B:?0.72;95% CI:?1.04, ?0.40), absence of glaucomatous optic neuropathy (P<0.001;beta: ?0.06;B: ?2.69;95%CI:–4.18, ?1.21) and absence of non-glaucomatous optic nerve damage (P?=?0.001;beta: ?0.06;B: ?4.80;95%CI:0. ?7.64, ?1.96). Localized RNFL defects were detected in 96 subjects (prevalence:3.7±0.45% (95% confidence interval(CI):3.0,4.4). In multivariate analysis, prevalence of localized RNFL defects was associated with higher blood pressure (P<0.001; odds ratio (OR):1.07;95%CI:1.03,1.10), higher concentration of low-density lipoproteins (P?=?0.01;OR:1.42;95%CI:1.08,1.85), higher prevalence of glaucomatous optic neuropathy (P<0.001;OR:46.8;95%CI:19.4,113) and diabetic retinopathy (P?=?0.002;OR:3.20;95%CI:1.53,6.67), and lower total RNFL visibility (P<0.001;OR:0.92;95%CI:0.88,0.96). Conclusions In Chinese aged 45+ years, a decreased RNFL visibility was associated with older age, male gender, dyslipidemia, hyperglycemia, myopia, larger optic disc, and glaucomatous or non-glaucomatous optic neuropathy. Localized RNFL defects (prevalence:3.7±0.45%) were correlated mainly with higher blood pressure, higher concentration of low-density lipoproteins, glaucomatous optic neuropathy and diabetic retinopathy. These data are helpful for the routine ophthalmoscopic examination of the RNFL.

Zhang, Yaqin; Xu, Liang; Zhang, Li; Yang, Hua; Wang, Ya Xing; Jonas, Jost B.

2013-01-01

92

Detecting the inner and outer borders of the retinal nerve fiber layer using optical coherence tomography  

Microsoft Academic Search

Background. The purpose of this study was to develop a new algorithm to detect the inner and outer borders of the retinal nerve fiber layer (RNFL) using optical coherence tomography (OCT). Methods. A program featuring a new algorithm was developed using a commercially available software development environment. The algorithm searches for peaks on each sampling line instead of applying conventional

Hiroshi Ishikawa; Scott Piette; Jeffrey M. Liebmann; Robert Ritch

2002-01-01

93

Retinal Nerve Fiber Layer Thinning in CADASIL: An Optical Coherence Tomography and MRI Study  

Microsoft Academic Search

Background and Purpose: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is considered a genetic form of small-vessel disease causing subcortical dementia. A relevant role of axonal injury was recently proposed to explain disability and cognitive decline in this disease. The retinal nerve fiber layer (RNFL) is the only part of the brain where unmyelinated axons can be

Alessandra Rufa; Elena Pretegiani; Paolo Frezzotti; Nicola De Stefano; Gabriele Cevenini; Maria Teresa Dotti; Antonio Federico

2011-01-01

94

Vinylimidazole chemisorption fibre  

Microsoft Academic Search

The conditions were developed for synthesis of a copolymer of acrylonitrile and vinylimidazole in dimethyl sulfoxide capable of forming complexes with transition metals. Fabrication of a chemisorption fibre from AN-VIM copolymer was investigated. It was found that an increase in the concentration of VIM in the copolymer above 35 wt. % lowered the physicomechanical properties of the fibre. Incorporation of

N. F. Kalyanova; A. N. Barash; M. P. Zverev

1996-01-01

95

layer  

Microsoft Academic Search

This paper analyzes the propagation of a cohesive crack through a reinforcement layer and gives a solution that can be used for any specimen and loading condition. Here it faces the case of a reinforced prismatic beam loaded at three points. Reinforcement is represented by means of a free-slip bar bridging the cracked section, anchored at both sides of the

Gonzalo Ruiz

96

Fibre and enteral nutrition.  

PubMed Central

The recent launch of a number of fibre enriched polymeric diet in the United States and Europe has stimulated considerable interest in the topic of fibre and enteral nutrition, and several commercial concerns appear to be under considerable pressures from their consumers to produce similar products. As a means of identifying areas of potential application of fibre to enteral nutrition some of the recent knowledge gained about the physical properties of dietary fibre and the processes involved in the intestinal assimilation of fibre has been reviewed. Two areas of interest are identifiable. The first relates to the bulking properties of fibre and the application of this to the regulation of bowel function in enterally fed patients. It is clear from the clinical studies that have been reviewed that there remains a paucity of controlled data, and a great deal more research is needed before widespread use of fibre supplemented diets can be supported. Perhaps of greater interest academically is the potentially beneficial effects that appear to be exerted by the VFA's, liberated as a consequence of colonic bacterial fermentation of fibre, on morphology and function of ileal and colonic mucosa. Although there are a number of potential applications of fibre supplemented enteral diets in this area, more research is required before any firm recommendations can be made about recommending their use. The one exception concerns patients with the nutritionally inadequate short bowel syndrome. There does seem to be sufficient experimental evidence to suggest that clinical studies should be commenced using a pectin supplemented predigested 'elemental' diet in these patients. Overall therefore, one is forced to conclude that the increasing interest and use of fibre supplemented enteral diets is being driven more by market than scientific forces. Nevertheless, the promotion of these diets has already provided a powerful stimulus to the scientific community, and it remains entirely possible that many of the potential applications of these diets will be realised in the near future.

Silk, D B

1989-01-01

97

Compressive strength of fibre composites with random fibre waviness  

Microsoft Academic Search

The compressive strength of unidirectional long fibre composites is predicted for plastic microbuckling from a random two-dimensional distribution of fibre waviness. The effect of the physical size of waviness is addressed by using couple stress theory, with the fibre bending resistance scaling with the fibre diameter d. The predicted statistical distribution of compressive strength is found using a Monte Carlo

D. Liu; N. A. Fleck; M. P. F. Sutcliffe

2004-01-01

98

Integrated fibres for self-monitored optical transport  

NASA Astrophysics Data System (ADS)

The ability to integrate distinct functional elements into a single device structure enables the realization of systems with higher-level functionality. Here we report on the design and fabrication of a fibre device structure that contains integrated optical, electrical and thermal elements for self-monitored optical transport. The fibre transmission element uses a hollow-core multilayer cylindrical photonic bandgap structure designed to guide high-power radiation at 10.6 ?m along the fibre axis. Multiple thermal-detection elements are placed in the vicinity of the hollow core for the purpose of temperature monitoring along the entire fibre length. Metal wires bridged by a semiconductor layer extend along the length of the fibre and deliver an electrical response to the fibre ends on change in the fibre temperature. The multimaterial fibre is drawn at high speeds from a single preform to produce extended lengths of optically and thermally functional fibres. The exponential dependence on temperature of the electrical conductivity of the semiconducting material allows for the discrimination, in real time, between normal transmission conditions and those that are indicative of localized defect formation, thus enabling a self-monitoring high-power optical transmission line for failure prediction and prevention.

Bayindir, Mehmet; Shapira, Ofer; Saygin-Hinczewski, Dursen; Viens, Jeff; Abouraddy, Ayman F.; Joannopoulos, John D.; Fink, Yoel

2005-11-01

99

Changes in retinal nerve fiber layer and optic disc algorithms by optical coherence tomography in glaucomatous Arab subjects  

PubMed Central

Purpose To assess the difference in retinal nerve fiber layer (RNFL) and optic disc algorithms between glaucomatous and normal Arab subjects using optical coherence tomography (OCT). Methods RNFL thickness and optic disc parameters were obtained in 65 patients aged 50.1 ± 7.7 years. Percentage differences in all parameters were calculated and analyzed between groups. Results The mean RNFL thickness around the disc and at all quadrants was significantly thinner in glaucomatous eyes than in normal eyes (P < 0.01). The greatest decrease in RNFL thickness was observed at the inferior (39.5%) and superior (39.3%) quadrants and at 1 o’clock (43%) and 5 o’clock (40%) hour sectors. Significant differences were observed between glaucomatous and control eyes in all disc parameters (P < 0.005) assessed. The disc area, cup area, mean cup/disc ratio, and vertical and horizontal cup/disc ratios were significantly larger (P < 0.01), whereas the vertical integrated rim area, horizontal integrated rim width, and rim area were significantly smaller (P < 0.001) in glaucomatous eyes than in normal eyes. Conclusion Stratus OCT is still a valuable tool in the diagnosis of early glaucoma changes and, as such, its use should be encouraged in glaucoma clinics in Saudi Arabia. The best OCT parameters for detecting early glaucoma change were RNFL thickness in the inferior, superior, and 1 o’clock hour sector; the cup area; and the vertical integrated rim area of the optic disc.

Zeried, Ferial M; Osuagwu, Uchechukwu L

2013-01-01

100

Optical fibre biosensors for oxygen and glucose monitoring  

NASA Astrophysics Data System (ADS)

An optical fibre biosensor that uses an oxygen sensitive coating; Ruthenium complex [Dichlorotris(1,10-phenantroline)-ruthenium(II) hydrate], incorporated into an adhesive inorganic-organic hybrid polymer coating (ORMOCER) is described. The Ruthenium/ ORMOCER layer is used with optical fibres to form an extrinsic or intrinsic sensor. It can be applied to a microscope slide or lens to be interrogated by optical fibres, or form a cladding layer for an evanescent field optical fibre sensor. The Ruthenium complex is caused to fluoresce by a high brightness blue LED at 470 nm and the excitation light at 600nm is detected by a photomultiplier tube used as a photon counter, to measure fluorescence lifetime. The fluorescence is quenched by oxygen depletion within the layer, which can be linked to glucose by incorporation of suitable enzymes. The detection threshold is 0.7mg(O2)/litre, and the sensitivity is 70 ns/mg per litre.

Young, J. S.; Scully, Patricia J.; Kvasnik, F.; Rose, K.; Kuncova, Gabriela; Podrazky, O.; Matejec, Vlastimil; Mrazek, Jan

2005-05-01

101

Modelling photonic crystal fibres  

NASA Astrophysics Data System (ADS)

One of the potential applications of photonic crystals is the so-called photonic crystal fibres. These systems can be constructed, for example, using a long thread of silica glass with a periodic array of airholes running down its length. If the central hole is absent, we generate a high-index ``defect'' in the repeating structure which acts like the core of an optical fibre. We study the propagation of light in these fibres. We solve the Maxwell equations using the plane wave expansion and the super cell method.

Arriaga, J.; Knight, J. C.; Russell, P. St. J.

2003-04-01

102

Strength distribution of elementary flax fibres  

Microsoft Academic Search

Flax fibres, along with a number of other natural fibres, are being considered as an environmentally friendly alternative of synthetic fibres in fibre-reinforced polymer composites. A common feature of natural fibres is a much higher variability of mechanical properties. This necessitates study of the flax fibre strength distribution and efficient experimental methods for its determination. Elementary flax fibres of different

J. Andersons; E. Sp?rni?š; R. Joffe; L. Wallström

2005-01-01

103

The development of topographical maps and fibre types in toad (Bufo marinus) glutaeus muscle during synapse elimination.  

PubMed Central

1. The toad glutaeus muscle consists of two muscle compartments. A study has been made of the topographical distribution of motor units in these compartments, in relation to the fibre types which arise during different stages of development. 2. Monoclonal antibodies to myosin allowed the distribution of fibre types to be determined. In mature muscles (from toads of greater than 30 g body weight) clusters of type 5 (tonic) fibres were found exclusively at the dorsal surface of the muscle, surrounded by a layer of type 3 (slow-twitch) fibres. A homogeneous layer of type 2 (fast-twitch red) fibres was found beneath this dorsal rind of slow and tonic fibres. The rest of the muscle, including the ventral surface, consisted of a mosaic of type 1 (fast-twitch white) and type 2 fibres. 3. Glycogen-depletion methods, together with the myosin antibodies, allowed the distribution of single motor units and their fibre types to be determined. In mature muscles, axons originating from rostral spinal cord possessed muscle units located in a band extending from the ventral surface to beyond the middle of the muscle; these units consisted of 78% type 1 and 22% type 2 fibres found amongst the mosaic of type 1 and type 2 fibres. Intermediate axons possessed muscle units located primarily in the middle and dorsal half of the muscle. These units consisted mostly of type 2 fibres (29% type 1, 71% type 2) also found amongst the mosaic of type 1 and type 2 fibres. Thus rostral and intermediate units were of mixed fibre type, with type 1 fibres predominating in the former units and type 2 in the latter. Caudal axons possessed muscle units located mostly in the homogeneous layer of type 2 fibres, beneath the dorsal rind of tonic fibres; these units were almost always composed entirely of type 2 fibres. 4. The distribution of single motor units and their fibre types were determined for the caudal axons during development. In juvenile animals (toads of about 10 g body weight) the dorsal rind of tonic and slow fibres, together with the underlying homogeneous layer of type 2 fibres, were still present, but the rest of the muscle to the ventral surface consisted almost entirely of type 1 fibres. Caudal axons innervated the type 2 fibre layer at the dorsal surface as they do in mature animals. 5. The glutaeus in post-metamorphic toads (0.15 g body weight) had only a small number of tonic and slow-twitch fibres in the very dorsal layer of cells; the muscle was largely type 1.(ABSTRACT TRUNCATED AT 400 WORDS) Images Fig. 7 Fig. 3 Fig. 4 Fig. 10

Bennett, M R; Davies, A M; Everett, A W

1989-01-01

104

Flax fibre–polyester composites  

Microsoft Academic Search

Composites of an aliphatic polyester (Bionolle) with natural flax fibres are prepared by batch mixing. The effect of processing conditions on fibre length distribution and the dependence of the composite mechanical properties on fibre content are investigated. The tensile modulus changes with fibre content according to the modified rule-of-mixture equation, with a fibre orientation efficiency factor ?0=0.194. The strength of

Massimo Baiardo; Elisa Zini; Mariastella Scandola

2004-01-01

105

The Optical Fibre  

Microsoft Academic Search

\\u000a The optical fibre now clearly appears to be the best medium for propagating light signals over long distances. But this now\\u000a well-established fact has not always been so obvious and some major technological achievements in glass fabrication were necessary\\u000a to finally conceive the idea of optical fibre based communication systems. As a matter of fact, the idea of guiding light

Réal Vallée

106

Highly efficient cladding-pumped fibre laser based on an ytterbium-doped optical fibre and a fibre Bragg grating  

SciTech Connect

Ytterbium-ion-doped double-clad optical fibres were developed. The differential quantum efficiency of a diode-pumped fibre laser, fabricated on the basis of such optical fibres with a fibre Bragg grating, was 90%. (lasers)

Kurkov, Andrei S; Karpov, V I; Medvedkov, O I; Dianov, Evgenii M; Vasil'ev, Sergei A; Paramonov, Vladimir M; Protopopov, V N [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Laptev, A Yu; Gur'yanov, A N; Umnikov, A A; Vechkanov, N I [Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation); Artyushenko, V G; Frahm, J [Advanced Photonic Systems, APhS GmbH, Berlin (Germany)

1999-06-30

107

Influence of Fineness, Stiffness and Load-Displacement Characteristics of Natural Fibres on the Properties of Natural Fibre-Reinforced Polymers  

Microsoft Academic Search

The object of this study is the examination of micro-mechanical calculation models for the determination of stiffness and impact resistance of a fibre-reinforced epoxy-single-layer-composite. Cotton, ramie and man-made lyocell fibres were used in this work. In the calculation of the elasticity module it turned out that for ramie fibres there is a good consistency between theory and experiment. To correct

Jörg Müssig; Sebastian Rau; Axel S. Herrmann

2006-01-01

108

Laser based coating and modification of carbon fibres: application of industrial lasers to manufacturing of composite materials  

Microsoft Academic Search

For high temperature applications of fibre reinforced ceramic composites, the adhesion, and chemical reactions at the fibre-matrix interface, has to be engineered by coating the fibres. Based on a technological 5 kW cw-CO2 laser, an atmospheric pressure laser assisted CVD process has been established performing a continuous high rate coating of carbon fibre rovings. Layers of pyrolytic carbon have been

V. Hopfe; R. Jäckel; K. Schönfeld

1996-01-01

109

Dual-band spectral-domain optical coherence tomography for in vivo imaging the spectral contrasts of the retinal nerve fiber layer  

PubMed Central

The ultimate goal of the study is to provide an imaging tool to detect the earliest signs of glaucoma before clinically visible damage occurs to the retinal nerve fiber layer (RNFL). Studies have shown that the optical reflectance of the damaged RNFL at short wavelength (<560nm) is reduced much more than that at long wavelength, which provides spectral contrast for imaging the earliest damage to the RNFL. To image the spectral contrast we built a dual-band spectral-domain optical coherence tomography (SD-OCT) centered at 808nm (NIR) and 415nm (VIS). The light at the two bands was provided by the fundamental and frequency-doubled outputs of a broadband Ti:Sapphire laser. The depth resolution of the NIR and VIS OCT systems are 4.7µm and 12.2µm in the air, respectively. The system was applied to imaging the rat retina in vivo. Significantly different appearances between the OCT cross sectional images at the two bands were observed. The ratio of the light reflected from the RNFL over that reflected from the entire retina at the two bands were quantitatively compared. The experimental results showed that the dual-band OCT system is feasible for imaging the spectral contrasts of the RNFL.

Zhang, Xiangyang; Hu, Jianming; Knighton, Robert W.; Huang, Xiang-Run; Puliafito, Carmen A.; Jiao, Shuliang

2011-01-01

110

Nanostructured optical fibre sensors for breathing airflow monitoring  

Microsoft Academic Search

A nanostructured optical fibre-based thin film sensor was designed for non-invasive, fast and reliable monitoring of respiratory airflow. Molecular-level self-assembly processing method was used to form multi-layered inorganic nanocluster and polymer thin films on the distal ends of optical fibres to form such sensors. In order to optimize the sensing performance, an analytical model based on the condensation of exhaled

Y. Kang; H. Ruan; Y. Wang; F. J. Arregui; I. R. Matias; R. O. Claus

2006-01-01

111

Birefringence Phenomena in Kidney-shaped Multilayer Fibres  

Microsoft Academic Search

A theoretical treatment of the shape of Fizeau fringes crossing a multilayer fibre of kidney-shaped cross-section is presented. A mathematical expression is derived and used to estimate the refractive indices and the birefringence of Dralon-K polyacrylonitrile fibre. Variation of refractive index with temperature is reported. The resulting data were utilized to calculate the polarizability per unit volume for each layer.Applications

I. M. Fouda; M. M. El Niklawy; K. A. El Farhaty; T. El Dessouki

1987-01-01

112

Tensile fatigue properties of fibre Bragg grating optical fibre sensors  

Microsoft Academic Search

This paper presents an experimental study into the tensile strength and fatigue properties of uncoated optical glass fibres containing Bragg grating (FBG) sensors. The protective polymer coating of the optical fibres must be removed by chemical or mechanical stripping methods to produce the Bragg gratings in the fibre core. This paper investigates the effects of chemical or mechanical stripping on

J. Ang; H. C. H. Li; I. Herszberg; M. K. Bannister; A. P. Mouritz

2010-01-01

113

Dietary fibres, fibre analogues, and glucose tolerance: importance of viscosity  

Microsoft Academic Search

To define the type of dietary fibre of fibre analogue with the greatest potential use in diabetic treatment, groups of four to six volunteers underwent 50-g glucose tolerance tests (GTT) with and without the addition of either guar, pectin, gum tragacanth, methylcellulose, wheat bran, or cholestyramine equivalent to 12 g fibre. The addition of each substance significantly reduced blood glucose

D J Jenkins; T M Wolever; A R Leeds; M A Gassull; P Haisman; J Dilawari; D V Goff; G L Metz; K G Alberti

1978-01-01

114

Effects of multiple intravitreal anti-VEGF injections on retinal nerve fiber layer and intraocular pressure: a comparative clinical study  

PubMed Central

AIM To determine the effect of multiple injections of ranibizumab or bevacizumab on retinal nerve fiber layer (RNFL) and intraocular pressure (IOP) in patients with age-related macular degeneration (AMD). METHODS This retrospective study includes 35 eyes of 35 patients treated with intravitreal bevacizumab (IVB, 1.25mg/0.05mL) and 30 eyes of 30 patients with intravitreal ranibizumab (IVR, 0.5mg/0.05mL) who had Fast RNFL analysis (Stratus™); IOP measurements were taken 30 minutes and 24 hours after each injection. RESULTS The mean ages were 68.0±7.5 and 69.1±7.7 years in the IVR and IVB groups, respectively (P=0.55). They underwent (6.3±1.9) and (5.1±1.3) injections (P=0.07) over (13.6±2.1) and (14.05±2.6) months (P=0.45) in the IVR and IVB groups, respectively. Changes in overall and temporal RNFL thickness in IVR-treated eyes (105.3±6.9µm and 74.4±11.2µm) were not different from those in untreated eyes in the IVR group (104.6± 8.4µm and 75.1±12.6µm) (P=0.57 and P=0.41, respectively). Similarly, overall and temporal RNFL thickness in IVB-treated eyes (105.8±8.1µm and 74.5±11.8µm) were not different from those in untreated eyes in the IVB group (104.6±8µm and 74.8±12.9µm) (P=0.42 and P=0.80, respectively). The frequencies of IOP rise (P=0.60) and changes in RNFL thickness from baseline (P=0.16) were comparable between groups. CONCLUSION Repeated intravitreal injection of ranibizumab or bevacizumab does not seem have adverse effects on RNFL thickness or IOP in wet AMD patients.

Sobac?, Gungor; Gungor, R?za; Ozge, Gokhan

2013-01-01

115

High-Resolution Imaging of the Retinal Nerve Fiber Layer in Normal Eyes Using Adaptive Optics Scanning Laser Ophthalmoscopy  

PubMed Central

Purpose To conduct high-resolution imaging of the retinal nerve fiber layer (RNFL) in normal eyes using adaptive optics scanning laser ophthalmoscopy (AO-SLO). Methods AO-SLO images were obtained in 20 normal eyes at multiple locations in the posterior polar area and a circular path with a 3–4-mm diameter around the optic disc. For each eye, images focused on the RNFL were recorded and a montage of AO-SLO images was created. Results AO-SLO images for all eyes showed many hyperreflective bundles in the RNFL. Hyperreflective bundles above or below the fovea were seen in an arch from the temporal periphery on either side of a horizontal dividing line to the optic disc. The dark lines among the hyperreflective bundles were narrower around the optic disc compared with those in the temporal raphe. The hyperreflective bundles corresponded with the direction of the striations on SLO red-free images. The resolution and contrast of the bundles were much higher in AO-SLO images than in red-free fundus photography or SLO red-free images. The mean hyperreflective bundle width around the optic disc had a double-humped shape; the bundles at the temporal and nasal sides of the optic disc were narrower than those above and below the optic disc (P<0.001). RNFL thickness obtained by optical coherence tomography correlated with the hyperreflective bundle widths on AO-SLO (P<0.001) Conclusions AO-SLO revealed hyperreflective bundles and dark lines in the RNFL, believed to be retinal nerve fiber bundles and Müller cell septa. The widths of the nerve fiber bundles appear to be proportional to the RNFL thickness at equivalent distances from the optic disc.

Takayama, Kohei; Ooto, Sotaro; Hangai, Masanori; Arakawa, Naoko; Oshima, Susumu; Shibata, Naohisa; Hanebuchi, Masaaki; Inoue, Takashi; Yoshimura, Nagahisa

2012-01-01

116

Radioluminescence of some optical fibres.  

PubMed

Measurement of radiation fields with small scintillators as detectors for radiation dose is an attractive method provided that the scintillator luminescence can be discriminated against other unwanted signals. In diagnostic radiology radioluminescence of the optical fibres required for a transmission of the luminescence to an optical detector is the only source for such an impairment of the signal. To find fibres with low radioluminosity a survey of ten commercial fibres including polystyrene (PS), polystyrene wavelength shifting fibres, poly-methylmetacrylate (PMMA) and silica as fibre core material was made. Measurements were made with two photomultipliers of different spectral response and a clinical x-ray unit. Lowest radioluminosity was obtained with PMMA fibres. Depending on spectral sensitivity of the multiplier clear PS fibres give five to ten times the luminescence of PMMA. From the silica fibres only one high-OH fibre gave comparable results for wavelength up to 520 nm. Wavelength shifting fibres and silica fibres with low OH-content show strong fluorescence and are not suitable fibre materials. PMID:17264357

Nowotny, R

2007-01-30

117

Fibre: Implications for the consumer  

Microsoft Academic Search

Dietary fibre, popularly known as roughage, has been receiving considerable attention of late, in both the scientific medica and the lay press. New research findings will necessitate a redefinition of what is truly meant by “fibre” and the challenge will be how to convey this to the consumer. Dietary fibre consumption patterns vary from one part of the world to

Ruth K. Oniang'o

1998-01-01

118

[Damage of macular ganglion cell complex and peripapillary retinal nerve fiber layer in multiple sclerosis].  

PubMed

The aim of this study was to evaluate macular ganglion cell complex (GCC) characteristics and peripapillary retinal nerve fiber layer (RNFL) thickness in patients with multiple sclerosis (MS) and to investigate the associations between these parameters and clinical characteristics of patients for evaluation perspectives of using this method for monitoring of disability and neurodegenerative processes. We examined a total of 113 participants (analysis of 211 eyes), divided into three groups: 1. 48 MS patients (66 eyes) with a history of optic neuritis (ON); 2. 35 MS patients (70 eyes) without a history of ON; 3. 30 disease-free control subjects (45 eyes). The estudy included anamnesis collection, neurological examination with assessment of EDSS scores. Refracted visual acuity prior to optical coherence tomography (OCT) was tested. RTVue-100 ??? system was used to assess peripapillary RNFL thickness and macular inner parameter (protocol GCC). The strongly correlated decline of the most RNFL and GCC indices was characteristic of all groups of MS patients with and without ON compared to controls. The damage of GCC was greater in patients with ON. The inverse correlation was found between the indices studied and the level of patient's disability. The study of GCC and RNFL thickness can be used to describe and characterize the level of axonal damage in MS and for objectification of neurodegenerative process in studies on neuroprotection and neuroreparation. PMID:22677679

Davydovskaia, M V; Tsysar', M A; Bo?ko, A N; Akopian, V S; Semenova, N S; Filonenko, I V; Fomin, A V; Gusev, E I

2012-01-01

119

Comparison of macular and retinal nerve fiber layer thickness in untreated and treated binocular amblyopia.  

PubMed

Abstract Purposes: To identify morphological retinal relationships to visual acuity (VA), refraction and axial length in binocular hyperopic amblyopia. Materials and methods: Children (n?=?118), ages 5-12 years, were divided into three groups: those with current amblyopia (n?=?53), those with fully corrected previous amblyopia (n?=?26) and those with emmetropia and normal VA (n?=?39). Macular thickness and peripapillary retinal nerve fiber layer (RNFL) thickness were measured by optical coherence tomography (OCT) and compared among the three groups. Results: The outer macular ring and RNFL of the current amblyopia group were significantly (independent t-test) thicker than those of the emmetropia group. However, significance of this difference disappeared after adjustment for axial length and refractive error. There was no significant difference in foveal or inner macular ring thickness among the three groups, either before or after adjustment for age, gender, axial length, and refractive error. When controlled for age, gender and VA, outer macular ring and RNFL thicknesses correlated with axial length (r?=?-0.350 and -0.334, respectively; p?RNFL thicknesses appear to be more extensively associated with differences in axial length and refraction than with amblyopic development, based on the fact that these thicknesses remained unchanged after amblyopic treatment. PMID:24073963

Chen, Wuhe; Chen, Jie; Huang, Jinhai; Xu, Jinling; Zhang, Fang; Lu, Fan

2013-09-27

120

Assessment of peripapillary retinal nerve fiber layer thickness in children with vitamin B12 deficiency.  

PubMed

PURPOSE: Vitamin B12 deficiency is a worldwide problem. It affects all ages, including children. It is one of the most common nutritional disorders and can cause harmful effects on the nervous system. In this study, we compared the peripapillary retinal nerve fiber layer thickness (RNFLT) in a healthy control group with children with vitamin B12 deficiency. In our study, we aimed to evaluate the effect of vitamin B12 deficiency on the RNFLT in children with the optical coherence tomography (OCT) method. METHODS: Sixty-six children with a diagnosis of vitamin B12 deficiency (patient group) and 66 age- and sex-matched healthy children (control group) were enrolled in this prospectively designed study. Blood counts, vitamin B12 levels, folate levels, and full biochemical parameters were obtained for all the subjects in each group. Peripapillary RNFLT measurements were performed with Cirrus HD spectral domain OCT. RESULTS: The thickness of the superior retinal nerve fiber layer (RNFL) in the vitamin B12 deficiency group was significantly lower than that of the control group (p?=?0.037). Although the average thickness of the RNFL was lower in the patient group, there was no statistically significant differences (p?=?0.216). In the vitamin B12 deficiency group, the average RNFL thickness and the superior RNFL thickness were significantly correlated with vitamin B12 levels (r 1?=?0.353, p 1?RNFL. PMID:23677174

Ozkasap, Serdar; Türkyilmaz, Kemal; Dereci, Selim; Oner, Veysi; Calapo?lu, Tu?ba; Cüre, Medine Cumhur; Durmu?, Mustafa

2013-05-16

121

Microstructures of ceramic composites with glass–ceramic matrices reinforced by SiC-based fibres  

Microsoft Academic Search

A lot of studies have been carried out on the fibre\\/matrix interfaces in glass–ceramic matrix composites reinforced by SiC based fibres. Chemical and structural analyses at the nanometer scale have shown that the fibre\\/matrix interface has a very complex structure consisting of several sublayers. The most important point is the existence of a thin carbon layer which is often found

Jean Vicens; Gaëlle Farizy; Jean-Louis Chermant

2003-01-01

122

Mechanical performance of oil palm empty fruit bunches\\/jute fibres reinforced epoxy hybrid composites  

Microsoft Academic Search

Oil palm empty fruit bunches (EFB)\\/jute fibre reinforced epoxy hybrid composites with different sequence of fibre mat arrangement such as EFB\\/jute\\/EFB and jute\\/EFB\\/jute were fabricated by hand lay-up method. The effect of layering patterns on the mechanical performance of the composites was studied. The hybrid composites are intended for engineering applications as an alternative to synthetic fibre composites. Mechanical performance

M. Jawaid; H. P. S. Abdul Khalil; A. Abu Bakar

2010-01-01

123

Development of Fibre Metal Laminates: concurrent multi-scale modeling and testing  

Microsoft Academic Search

Fibre Metal Laminates (FML) represent a family of hybrid materials, consisting of alternating layers of thin metal sheets\\u000a and fibre reinforced epoxies. The concept, invented in the late 1970s, has resulted in laminates like ARALL and GLARE. The\\u000a first material is made of aluminum alloys, aramid fibres and an epoxy resin, GLARE laminates use similar constituents except\\u000a for the aramid

J. Sinke

2006-01-01

124

Numerical Modelling of Fibre Metal Laminates Subjected to Blast Loading  

NASA Astrophysics Data System (ADS)

In this paper, finite element models were developed to simulate fibre metal laminates subjected to various blast loadings with typical pressure-time patterns. The aluminium (alloy grade 2024-0) layer was modelled as an isotropic elasto-plastic material up to the on-set of post failure stage, followed by shear failure and tensile failure to simulate its failure mechanism. The glass fibre laminate (woven glass-fibre/polypropylene matrix composite) layer was modelled as an orthotropic material up to its on-set of damage, followed by damage initiation and evolution using the Hashin criterion. The damage initiation was controlled by failure tensile and compressive stresses within the lamina plane which were primarily determined by tests. The damage evolution was controlled by tensile/compressive fracture energies combined both fibre and matrix. Discussions were given to cover difficulties faced during development of the modelling. The FE models developed for 2/1 and 3/2 fibre metal laminates with different GFPP layer thicknesses were validated against the corresponding experimental results. Good correlation was obtained in terms of failure modes and permanent displacements. Using validated models, parametric studies may be further carried out to cover FMLs made with various stack sequences and layer thicknesses.

Guan, Z. W.; Cantwell, W. J.

2010-05-01

125

Inner Nuclear Layer Thickening Is Inversley Proportional to Retinal Ganglion Cell Loss in Optic Neuritis  

PubMed Central

Aim To examine the relationship between retinal ganglion cell loss and changes in the inner nuclear layer (INL) in optic neuritis (ON). Methods 36 multiple sclerosis (MS) patients with a history of ON and 36 age and sex-matched controls underwent Optical Coherence Tomography. The paramacular retinal nerve fiber layer (RNFL), combined ganglion cell and inner plexiform layers (GCL/IPL) and inner nuclear layer (INL) thickness were measured at 36 points around the fovea. To remove inter-subject variability, the difference in thickness of each layer between the ON and fellow eye of each patient was calculated. A topographic analysis was conducted. Results The INL of the ON patients was thicker than the controls (42.9µm versus 39.6µm, p=0.002). ON patients also had a thinner RNFL (27.8µm versus 32.2µm, p<0.001) and GCL/IPL (69.3µm versus 98.1µm, p<0.001). Among the controls, there was no correlation between RNFL and GCL/IPL as well as RNFL and INL, but a positive correlation was seen between GCL/IPL and INL (r=0.65, p<0.001). In the ON group, there was a positive correlation between RNFL and GCL/IPL (r=0.80, p<0.001) but a negative correlation between RNFL and INL (r=-0.61, p<0.001) as well as GCL/IPL and INL (r=-0.44, p=0.007). The negative correlation between GCL/IPL and INL strengthened in the ON group when inter-subject variability was removed (r=-0.75, p<0.001). Microcysts within the INL were present in 5 ON patients, mainly in the superior and infero-nasal paramacular regions. While patients with microcysts lay at the far end of the correlation curve between GCL/IPL and INL (i.e. larger INL and smaller GCL/IPL compared to other patients), their exclusion did not affect the correlation (r= -0.76, p<0.001). Conclusions INL enlargement in MS-related ON is associated with the severity of GCL loss. This is a continuous relationship and patients with INL microcysts may represent the extreme end of the scale.

Kaushik, Megha; Wang, Chen Yu; Barnett, Michael H.; Garrick, Raymond; Parratt, John; Graham, Stuart L.; Sriram, Prema; Yiannikas, Con; Klistorner, Alexandr

2013-01-01

126

Porous Silicon Micromachining to Position Optical Fibres in Silicon Integrated Optical Circuits  

Microsoft Academic Search

Low-loss optical fibre connections require deep grooves etched in silicon substrate for accurate fibre positioning. As shown in this paper these grooves can be obtained by using localised formation of porous silicon on patterned substrates. Cr-Au masking layer with a duration in HF solution longer than 30 min is used to fabricate grooves with a depth higher than 75 µm.

P. Joubert; M. Guendouz; N. Pedrono; J. Charrier

2000-01-01

127

On the development of a strength prediction methodology for fibre metal laminates in pin bearing  

Microsoft Academic Search

The development of Fibre Metal Laminates (FMLs) for application into aerospace structures represents a paradigm shift in airframe and material technology. By consolidating both monolithic metallic alloys and fibre reinforced composite layers, a new material structure is born exhibiting desired qualities emerging from its heterogeneous constituency. When mechanically fastened via pins, bolts and rivets, these laminated materials develop damage and

Peter Panagiotis Krimbalis

2009-01-01

128

X-ray measurements and the structure of polyacrylonitrile- and pitch-based carbon fibres  

Microsoft Academic Search

X-ray measurements were carried out on polyacrylonitrile- and pitch-based carbon fibres. The crystallites, disordered regions and microvoids in these carbon fibres were evaluated quantitatively by applying the methods previously proposed by the present authors. The structural parameters evaluated are the 1 1 plane spacing of the carbon layer, the average, standard deviation and asymmetry of the distribution of interlayer spacing,

A. Takaku; M. Shioya

1990-01-01

129

Axial compression fracture in carbon fibres  

Microsoft Academic Search

Axial compression fracture of carbon fibres was studied by embedding single fibres in epoxy resin and compressing the specimens parallel to the fibre axis. By careful optical monitoring of the fibre surface the earliest stages of fracture were identified leading to estimates of the fibre axial compression failure strengths. Compression strength decreases markedly from about 2.2 GN m-2 for moderately

H. M. Hawthorne; E. Teghtsoonian

1975-01-01

130

Relationship between birefringence and neurotubule density in the primate retinal nerve fiber layer  

NASA Astrophysics Data System (ADS)

The relationship between retinal nerve fiber layer (RNFL) birefringence (?n) and neurotubule density (NTD, retinal ganglion cell (RGC) neurotubules per unit RNFL area) was investigated by correlating measurements of these two parameters in 1 eye of a healthy cynomolgus monkey. Phase retardation per unit depth (PR/UD, proportional to ?n) was measured at 5.6-15o intervals around the optic nerve head (ONH) with an enhanced polarization-sensitive optical coherence tomography (EPS-OCT) instrument. Transverse tissue sections containing 3 RGC nerve fiber bundles from each peripapillary RNFL octant were imaged with a transmission electron microscope (TEM). Morphological measurements taken in TEM images were used by a novel algorithm to estimate NTD. Registered PR/UD and NTD data were then correlated using single- and multi-level models, yielding correlation coefficients in the range 0.49 <= r <= 0.61 (0.06 <= P <= 0.11). It was found that in order for the single-level correlation coefficient (r = 0.61) to be statistically significant (P <= 0.05) and powerful (Power >= 80%), NTD measurements in at least 16, rather than 8, RNFL sectors were needed. Interestingly, a single-level correlation coefficient of r = 0.81 (P = 0.01) was calculated between octant-averaged PR/UD and RGC axoplasmic area (Ax, axon area less non-cytoskeletal organelle area) mode. Ax represents a RGC axon's neurotubule-inhabitable area. Intuitively, a strong relationship should exist between Ax and neurotubule number if neurotubules provide the primary structural support for RGC axons and structural requirements are the same in all RGC axons. If this relationship exists, error resulting from NTD estimation methods or preservation artifacts may have caused lower observed correlations of PR/UD with NTD than with Ax mode, and more accurate methods of measuring in vivo NTD may be required to determine an accurate relationship between RNFL birefringence and NTD.

Aranibar, R. G.; Kemp, N. J.; Dwelle, J. C.; Byers, S. E.; Markey, M. K.; Milner, T. E.; Rylander, H. G.

2007-02-01

131

Modelling bird impacts on an aircraft wing – Part 1: Material modelling of the fibre metal laminate leading edge material with continuum damage mechanics  

Microsoft Academic Search

In a collaborative research project, aircraft wing leading edge structures with a glass-based Fibre Metal Laminate (FML) skin have been designed, built, and subjected to bird strike tests that have been modelled with finite element analysis. Fibre Metal Laminates have layers of aluminium alloy and high strength glass fibre composite and have been reported to possess excellent impact properties. In

M. A. McCarthy; J. R. Xiao; N. Petrinic; A. Kamoulakos; V. Melito

2005-01-01

132

Estimation of fibre and interfacial shear strength by using a single-fibre composite  

Microsoft Academic Search

The fibre\\/matrix interfacial shear strength is often estimated from the fragmentation process of a fibre in a single-fibre composite loaded in tension. The interfacial shear strength is calculated from a knowledge of the critical length and the tensile strength of the fibre. Unfortunately, if the tensile strength of fibres distributes widely and increases with decreasing fibre length, then problems arise

Masatoshi Shioya; Akira Takaku

1995-01-01

133

Improved fracture toughness of carbon fibre\\/epoxy composite laminates using dissolvable thermoplastic fibres  

Microsoft Academic Search

This paper reports on a novel toughening concept based on dissolvable phenoxy fibres, which are added at the interlaminar region in a carbon fibre\\/epoxy composite. The composites were prepared by resin infusion of carbon fibre fabric with the phenoxy introduced as a chopped fibre interleaf between the carbon fibre plies. The thermoplastic phenoxy fibre dissolved in the epoxy during curing

Doris W. Y. Wong; Lin Lin; P. Terry McGrail; Ton Peijs; Paul J. Hogg

2010-01-01

134

The exploitation of thin film coatings for fibre sensors for the application of chemical sensing  

NASA Astrophysics Data System (ADS)

We report on the use of thin film coatings, both single and multi-layered, deposited on the flat side of a lapped, D-shaped fibre to enhance the sensitivity of two kinds of surface plasmon resonance based optical fibre sensors. The first kind involves the use of a tilted Bragg grating inscribed within the fibre core, prior to fibre coating, while the second relies on a surface relief grating photoinscribed after the fibre has been coated. Some of the devices operate in air with high coupling efficiency in excess of 40dB and an estimated index sensitivity of ??/?n = 90nm from 1 to 1.15 index range showing potential for gas sensing. Other sensors produced index sensitivities (??/?n) ranging from 6790nm to 12500nm in the aqueous index regime. The materials used for these fibre optical devices are germanium, silica, silver, gold and palladium.

Allsop, T.; Neal, R.; Kalli, K.; Davies, E. M.; Rehman, S.; Maier, R. R. J.; Barton, J.; Jones, J. D.; Webb, D. J.; Bennion, I.

2009-05-01

135

Novel fibre array assemble technology  

Microsoft Academic Search

This paper describes the utility of commercially available lensed fibre arrays in combination with standard mono-mode InP-based waveguides and the characterization of hemi-spherical lensed fibres with lens radii in the range of 5 µm - 15 µm. The alignment errors of commercial fibre-arrays are in the order of 1 µm - 2 µm. In combination with relatively large lens radii,

J. H. C. van Zantvoort; S. G. L. Plukker; E. C. A Dekkers; G. D. Khoe; A. M. J. Koonen; H. de Waardt

2004-01-01

136

Evaluation of peripapillary retinal nerve fiber layer, macula and ganglion cell thickness in amblyopia using spectral optical coherence tomography  

PubMed Central

AIM To investigate peripapillary retinal nerve fiber layer (RNFL), macula and ganglion cell layer thicknesses (GCC) in amblyopic eyes with spectral domain optical coherence tomography (SD-OCT). METHODS Thirty six patients with a history of unilateral amblyopia and thirty two children who had emmetropia without amblyopia were included in this study. In this institutional study, 36 eyes of 36 patients with amblyopia (AE), 36 fellow eyes without amblyopia (FE), and 32 eyes of 32 normal subjects (NE) were included. RNFL, GCC and macular thickness measurements were performed with RS-3000 OCT Retina Scan (Nidek Inc CA. USA). RESULTS The mean global thicknesses of the RNFL were 113.22±21.47, 111.57±18.25, 109.96±11.31µm in the AE, FE, and NE, respectively. There was no statistically significant difference for mean global RNFL thickness among the eyes (P=0.13). The mean thicknesses of the macula were 258.25±18.31, 258.75±19.54, 248.62±10.57µm in the AE, FE and NE, respectively. There was no statistically significant difference for thickness of macula among the eyes (P=0.06). The GCC was investigated into two parts: superior and inferior. The mean thicknesses of superior GCC were 102.57±13.32, 103.32±10.64, 100.52±5.88µm in the AE, FE, and NE, respectively. The mean thicknesses of inferior GCC were 103.82±12.60, 107.82±12.33, 105.86±10.79µm in the AE, FE and NE, respectively. There was no statistically significant difference for thickness of superior and inferior GCC between the eyes (P=0.63, P=0.46). CONCLUSION The macular thicknesses of AE and FE were greater than the NE, although it was not statistically significant. Amblyopia does not seem to have a profound effect on the RNFL, macula and GCC.

Firat, Penpe Gul; Ozsoy, Ercan; Demirel, Soner; Cumurcu, Tongabay; Gunduz, Abuzer

2013-01-01

137

Sulphur-doped silica fibres  

SciTech Connect

An optical fibre with low optical losses is manufactured from a sulphur-doped quartz glass. Optical absorption spectra are measured for various parts of the fibre core. Most of the bands of these spectra are assigned to oxygen-deficient centres and colour centres containing sulphur atoms. The photosensitivity of glasses exposed to laser radiation at wavelengths of 193 and 244 nm is investigated to estimate the possibility of their application for producing photorefracting devices. A Bragg grating of the refractive index with {Delta}n = 7.8 x 10{sup -4} is written in a sulphur-doped silica fibre. (fibre optics)

Gerasimova, V I; Rybaltovskii, A O; Chernov, P V [D.V. Skobel'tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Mashinsky, V M; Sazhin, O D; Medvedkov, O I; Rybaltovsky, A A; Khrapko, R R [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2003-01-31

138

Mechanical properties of ligament replacement with carbon fibres.  

PubMed

1. The tensile strength and modulus of elasticity of carbon fibres are comparable to those of stainless steel. 2. The small diameter (7-8 microns) produces high fibre flexibility, permitting braiding and weaving of this material. 3. The strength of braided ligament prostheses is about 2-3 times higher than the rupture strength of natural knee ligaments. 4. The elasticity and extensibility of a ligament prosthesis made of braided carbon fibres are higher than when there is a unidirectional arrangement. 5. The growth of connective tissue between the braided carbon fibres increases the elasticity and extensibility of the ligament replacement in vivo, so that 50-110% of the values for natural ligaments can be achieved. 6. The low shearing strength of the carbon fibres can be increased by a layer of collagen. 7. Intraosseous anchorages of the carbon fibre ligaments after 12 weeks of implantation exhibit strengths corresponding to 49-107% of the rupture strength of natural ligaments. PMID:6136232

Claes, L; Neugebauer, R

1983-01-01

139

Microscopical investigations on the epicuticle of mammalian keratin fibres.  

PubMed

The existence of a thin chemically resistant layer, the epicuticle, close to the surfaces of all undamaged mammalian keratin fibres has been known since 1916. The identification of such a specific structure within the fibre cuticle has remained elusive. Now, through transmission electron microscope investigations of stained transverse sections of hairs from various animal species, the epicuticle has been tentatively identified as a sharply defined and continuous layer approximately 13 nm thick covering the entire outwardly facing intracellular surface of every cuticle cell. The staining behaviour of the epicuticle leads one to suppose that it is rich in cystine and that thioester-bound lipids might be present within its bulk. With the atomic force microscope it was established that the undamaged outer surface of all mammalian keratin fibres, even including those from the monotremes, were longitudinally striated. The lateral spacing of the striations was always in the range 0.29-0.39 microm. Striations only occurred on the freely exposed outer surfaces of the original undamaged fibres; evidently arising by some, as yet undefined, interaction in the follicle with the cuticle of the inner root sheath. By stripping off fatty acids known to be covalently attached to the fibre's outer surface, the striations were shown to reflect a corresponding irregularity of the epicuticle's surface. PMID:11903797

Swift, J A; Smith, J R

2001-12-01

140

Biomimetic calcium phosphate coatings on recombinant spider silk fibres.  

PubMed

Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs. PMID:20539057

Yang, Liang; Hedhammar, My; Blom, Tobias; Leifer, Klaus; Johansson, Jan; Habibovic, Pamela; van Blitterswijk, Clemens A

2010-06-11

141

Termination of Optic Fibres in the Lateral Geniculate Body  

Microsoft Academic Search

IN a recent letter1, Prof. Le Gros Clark directed attention to the evidence that crossed and uncrossed fibres of the optic tract each terminate in three alternating layers of cells in the lateral geniculate body in the monkey. Hitherto, however, this has been an inference based on the indirect evidence of transneuronal atrophy. It has now been finally established in

P. Glees

1940-01-01

142

UV curing of optical fibre coatings using excimer lamps  

Microsoft Academic Search

In this paper, UV curing of optical fibre coatings using excimer lamp radiation has been demonstrated for the first time. These layers were prepared on silicon and quartz substrates by conventional spin coating and subsequently exposed to 172, 222nm or 308nm light from different excimer lamp sources. Ellipsometry, Fourier transform infrared (FTIR) spectroscopy and ultraviolet spectrophotometry have been used to

Jun-Ying Zhang; Gaelle Windall; Ian W. Boyd

2002-01-01

143

Post-stretching induced stress redistribution in Fibre Metal Laminates for increased fatigue crack growth resistance  

Microsoft Academic Search

Post-stretching is a potential method to change the unfavorable residual stress system in fibre metal laminates (FMLs). During post-stretching of the material, the metal layers will be strained into the plastic region of the stress–strain curve, while the fibre layers remain elastic. After unloading, the residual stress system due to curing will be reduced or even reversed dependent on the

S. U. Khan; R. C. Alderliesten; R. Benedictus

2009-01-01

144

The flow of continuous fibre-reinforced composites in steady shear  

Microsoft Academic Search

A theoretical study is made of the flow that occurs in a continuous fibre-reinforced laminate subject to steady shearing caused by the withdrawal of a rigid plate from within the laminate. The laminate is assumed to be a stack of resin-rich layers and plies with the resin-rich layers modelled as Newtonian liquids and the plies as inextensible fibre-reinforced liquids; the

J. A. Goshawk; R. S. Jones

1996-01-01

145

Investigation of industrial tea-leaf-fibre waste material for its sound absorption properties  

Microsoft Academic Search

The sound absorption of an industrial waste, developed during the processing of tea leaves has been investigated. Three different layers of tea-leaf-fibre waste materials with and without backing provided by a single layer of woven textile cloth were tested for their sound absorption properties. The experimental data indicate that a 1cm thick tea-leaf-fibre waste material with backing, provides sound absorption

Sezgin Ersoy; Haluk Küçük

2009-01-01

146

Naissance des fibres et homotopie  

Microsoft Academic Search

This is about an episode in the history of mathematics, very much restricted in content and in time: the origins of the homotopy theory of fibre spaces, roughly from 1935 to 1950 (the beginnings of the theory of vector bundles — fibre bundles, structure group, etc. — are not treated). During that period, the combination of Hurewicz's ideas concerning homotopy

Beno Eckmann; T. S. Eliot

147

Recrystallization of Relaxed Animal Fibres  

Microsoft Academic Search

IT is well known that wool fibres and human hair can be stretched 30 per cent in water at low temperatures (22° C.) without significant alteration of their elastic properties, provided that extension is carried out rapidly and release is immediate1. The released fibre returns exactly to its original length, and if it is allowed to stand in cold water

L. Jagger; J. B. Speakman

1949-01-01

148

Development of an electrically tuneable Bragg grating filter in polymer optical fibre operating at 1.55 µm  

Microsoft Academic Search

We present a thorough study on the development of a polymer optical fibre-based tuneable filter utilizing an intra-core Bragg grating that is electrically tuneable, operating at 1.55 µm. The Bragg grating is made tuneable using a thin-film resistive heater deposited on the surface of the fibre. The polymer fibre was coated via the photochemical deposition of a Pd\\/Cu metallic layer

K. Kalli; H. L. Dobb; D. J. Webb; K. Carroll; C. Themistos; M. Komodromos; G.-D. Peng; Q. Fang; I. W. Boyd

2007-01-01

149

Retinal nerve fiber layer thickness in subgroups of multiple sclerosis, measured by optical coherence tomography and scanning laser polarimetry.  

PubMed

Optical coherence tomography (OCT) and scanning laser polarimetry (GDx ECC) are non-invasive methods used to assess retinal nerve fiber layer (RNFL) thickness, which may be a reliable tool used to monitor axonal loss in multiple sclerosis (MS). The objectives of this study are (1) to compare OCT with the GDx ECC; (2) to assess and compare the RNFL thickness in subgroups of MS. Ophthalmologic examination and RNFL assessment by OCT and GDx were performed in 65 MS patients (26 relapsing-remitting (RRMS), ten secondary-progressive (SPMS), 29 primary-progressive (PPMS)). Twenty-eight patients (43%) had a history of optic neuritis (ON). Adjustments were made for age and disease duration. RNFL thickness was reduced in eyes with previous ON (p < 0.01). No differences were found between PPMS and relapse-onset MS. OCT and GDx ECC measurements were moderately correlated (rho = 0.73, p < 0.01). Visual field-mean deviation (MD) values correlated with OCT means (r = 0.44, p < 0.01) and GDx ECC TSNIT average (r = 0.41, p < 0.01). In patients without previous ON, EDSS correlated with MD (r = -0.36, p < 0.01), visual field-pattern standard deviation (PSD) (r = 0.30, p < 0.05), OCT means (r = -0.31-0.30, p < 0.05) and macular volume (r = -0.37, p < 0.01). For MSIS-29 physical impact score, significant correlations were found with MD (r = -0.48, p < 0.01) and PSD (r = 0.48, p < 0.01). Conclusions: No differences between PPMS and relapse-onset MS subgroups were found. RNFL thickness was reduced in eyes with previous ON. Although OCT and GDx ECC findings were moderately correlated and showed significant correlations with measures of visual function in patients without previous ON, EDSS correlated significantly with visual and OCT measures, but not with GDx ECC. PMID:20461397

Siepman, Theodora A M; Bettink-Remeijer, Marijke Wefers; Hintzen, Rogier Q

2010-05-12

150

Glaucoma Progression Detection by Retinal Nerve Fiber Layer Measurement Using Scanning Laser Polarimetry: Event and Trend Analysis  

PubMed Central

Purpose To evaluate the use of scanning laser polarimetry (SLP, GDx VCC) to measure the retinal nerve fiber layer (RNFL) thickness in order to evaluate the progression of glaucoma. Methods Test-retest measurement variability was determined in 47 glaucomatous eyes. One eye each from 152 glaucomatous patients with at least 4 years of follow-up was enrolled. Visual field (VF) loss progression was determined by both event analysis (EA, Humphrey guided progression analysis) and trend analysis (TA, linear regression analysis of the visual field index). SLP progression was defined as a reduction of RNFL exceeding the predetermined repeatability coefficient in three consecutive exams, as compared to the baseline measure (EA). The slope of RNFL thickness change over time was determined by linear regression analysis (TA). Results Twenty-two eyes (14.5%) progressed according to the VF EA, 16 (10.5%) by VF TA, 37 (24.3%) by SLP EA and 19 (12.5%) by SLP TA. Agreement between VF and SLP progression was poor in both EA and TA (VF EA vs. SLP EA, k = 0.110; VF TA vs. SLP TA, k = 0.129). The mean (±standard deviation) progression rate of RNFL thickness as measured by SLP TA did not significantly differ between VF EA progressors and non-progressors (-0.224 ± 0.148 µm/yr vs. -0.218 ± 0.151 µm/yr, p = 0.874). SLP TA and EA showed similar levels of sensitivity when VF progression was considered as the reference standard. Conclusions RNFL thickness as measurement by SLP was shown to be capable of detecting glaucoma progression. Both EA and TA of SLP showed poor agreement with VF outcomes in detecting glaucoma progression.

Moon, Byung Gil; Cho, Jung Woo; Kang, Sung Yong; Yun, Sung-Cheol; Na, Jung Hwa; Lee, Youngrok; Kook, Michael S.

2012-01-01

151

Changes in retinal nerve fiber layer thickness following mechanical microkeratome-assisted versus femtosecond laser-assisted LASIK  

PubMed Central

Purpose To study the influence of the transient elevation of intraocular pressure during suction in laser-assisted in situ keratomileusis (LASIK) on the retinal nerve fiber layer (RNFL) thickness both in microkeratome assisted and femotsecond (FS) LASIK. Patients and methods An interventional case series that included 40 eyes suffering from myopia who were candidates for LASIK. All underwent Wave Front Guided LASIK by the same surgeon using the VisX CustomVue platform. A corneal flap was created in 20 eyes using a mechanical microkeratome Moria M2 (MMK), while the IFS IntraLase™ was used in the remaining 20 eyes. Mean suction time was recorded from “Suction ON” to “Suction OFF” time. Optic cube and RNFL thickness analysis using Spectral Domain Optical Coherence Tomography (SD-OCT) Cirrus-HD was completed before, and 1 month after LASIK. Results The study included 40 eyes of 20 patients. All were females with mean age 33.5 ± 6.4 years. Mean preoperative spherical equivalent was ?3.62 ± 2.31D. Average preoperative RNFL thickness was 94.6 ± 12.1?m in MMK group while the postoperative average thickness was 95.1 ± 11.9 um with no statistically significant difference (P-value: 0.37). Average preoperative RNFL thickness was 108.28 ± 8.4 ?m in FS group compared to 108.38 ± 11.2 ?m in the postoperative average with no statistically significant difference (P-value: 0.94). Mean “Suction ON” to “Suction OFF” time was 22 seconds in the MMK group compared to 41 seconds in the FS group. Conclusion The rise of intraocular pressure during application of suction ring in LASIK surgery does not affect the RNFL thickness as measured by SD-OCT, whether the flap is created by MMK or FS.

Hosny, Mohamed; Zaki, Rania M; Ahmed, Rania A; Khalil, Noha; Mostafa, Hoda M

2013-01-01

152

Retinal Nerve Fiber Layer Thickness Measurement Comparability between Time Domain Optical Coherence Tomography (OCT) and Spectral Domain OCT  

PubMed Central

Purpose. Time domain optical coherence tomography (TD-OCT) has been used commonly in clinical practice, producing a large inventory of circular scan data for retinal nerve fiber layer (RNFL) assessment. Spectral domain (SD)-OCT produces three-dimensional (3-D) data volumes. The purpose of this study was to create a robust technique that makes TD-OCT circular scan RNFL thickness measurements comparable with those from 3-D SD-OCT volumes. Methods. Eleven eyes of 11 healthy subjects and 7 eyes of 7 subjects with glaucoma were enrolled. Each eye was scanned with one centered and eight displaced TD-OCT scanning circles. One 3-D SD-OCT cube scan was obtained at the same visit. The matching location of the TD-OCT scanning circle was automatically detected within the corresponding 3-D SD-OCT scan. Algorithm performance was assessed by estimating the difference between the detected scanning circle location on 3-D SD-OCT volume and the TD-OCT circle location. Global and sectoral RNFL thickness measurement errors between the two devices were also compared. Results. The difference (95% confidence interval) in scanning circle center locations between TD- and SD-OCT was 2.3 (1.5–3.2) pixels (69.0 [45.0–96.0] ?m on the retina) for healthy eyes and 3.1 (2.0–4.1) pixels (93.0 [60.0–123.0] ?m on the retina) for glaucomatous eyes. The absolute RNFL thickness measurement difference was significantly smaller with the matched scanning circle. Conclusions. Scan location matching may bridge the gap in RNFL thickness measurements between TD-OCT circular scan data and 3-D SD-OCT scan data, providing follow-up comparability across the two generations of OCTs.

Kim, Jong S.; Ishikawa, Hiroshi; Gabriele, Michelle L.; Bilonick, Richard A.; Kagemann, Larry; Fujimoto, James G.; Schuman, Joel S.

2010-01-01

153

Grating based devices in polymer optical fibre  

Microsoft Academic Search

We describe recent research into devices based on fibre Bragg gratings in polymer optical fibre. Firstly, we report on the inscription of gratings in a variety of microstructured polymer optical fibre: single mode, few moded and multimoded, as well as fibre doped with trans-4-stilbenmethanol. Secondly, we describe research into an electrically tuneable filter using a metallic coating on a polymer

H. Dobb; K. Carroll; D. J. Webb; K. Kalli; M. Komodromos; C. Themistos; G. D. Peng; A. Argyros; M. C. J. Large; M. A. van Eijkelenborg; Q. Fang; I. W. Boyd

2006-01-01

154

Muscle fibre type changes in hypothyroid myopathy  

Microsoft Academic Search

Changes in muscle fibre type in hypothyroid myopathy were studied by serial percutaneous needle biopsy of vastus lateralis before and during treatment with L-thyroxine. A type II fibre atrophy and loss was found, which correlated with the clinical and biochemical evidence of a myopathy. The type II fibre atrophy was corrected by L-thyroxine but type II fibre loss was still

R O McKeran; G Slavin; T M Andrews; P Ward; W G Mair

1975-01-01

155

Fracture mechanisms in wood fibre reinforced polyethylene  

Microsoft Academic Search

The fracture toughness of wood fibre reinforced polyethylene has been studied and several methods of improving this important property have been developed. A mechanistic fracture model which incorporates the features of wood fibres and the fibre\\/matrix interface was also developed. The modeling revealed that the key to enhancing the fracture toughness is to promote fibre pull-out during composite fracture. Based

Chengjie Zhang

1997-01-01

156

Why animals have different muscle fibre types  

Microsoft Academic Search

Animals have different muscle fibre types: slow fibres with a low maximum velocity of shortening ( Vmax) and fast fibres with a high Vmax. An advantage conferred by the use of different fibre types during locomotion1 has been proposed solely on the basis of their in vitro properties. Isolated muscle experiments show that force generation, mechanical power production and efficiency

Lawrence C. Rome; Roel P. Funke; R. Mcneill Alexander; Gordon Lutz; Hugh Aldridge; Frank Scott; Marvin Freadman

1988-01-01

157

G-fibres in storage roots of Trifolium pratense (Fabaceae): tensile stress generators for contraction.  

PubMed

Root contraction has been described for many species within the plant kingdom for over a century, and many suggestions have been made for mechanisms behind these contractions. To move the foliage buds deeper into the soil, the proximal part of the storage root of Trifolium pratense contracts by up to 30%. Anatomical studies have shown undeformed fibres next to strongly deformed tissues. Raman imaging revealed that these fibres are chemically and structurally very similar to poplar (Populus) tension wood fibres, which are known to generate high tensile stresses and bend leaning stems or branches upright. Analogously, an almost pure cellulosic layer is laid down in the lumen of certain root fibres, on a thin lignified secondary cell wall layer. To reveal its stress generation capacities, the thick cellulosic layer, reminiscent of a gelatinous layer (G-layer) in tension wood, was selectively removed by enzymatic treatment. A substantial change in the dimensions of the isolated wood fibre bundles was observed. This high stress relaxation indicates the presence of high tensile stress for root contraction. These findings indicate a mechanism of root contraction in T. pratense (red clover) actuated via tension wood fibres, which follows the same principle known for poplar tension wood. PMID:20030750

Schreiber, Nicole; Gierlinger, Notburga; Pütz, Norbert; Fratzl, Peter; Neinhuis, Christoph; Burgert, Ingo

2009-12-21

158

Multilayered Glass Fibre-reinforced Composites In Rotational Moulding  

SciTech Connect

The potential of multiple layer fibre-reinforced mouldings is of growing interest to the rotational moulding industry because of their cost/performance ratio. The particular problem that arises when using reinforcements in this process relate to the fact that the process is low shear and good mixing of resin and reinforcement is not optimum under those conditions. There is also a problem of the larger/heavier reinforcing agents segregating out of the powder to lay up on the inner part surface. In this study, short glass fibres were incorporated and distributed into a polymer matrix to produce fibre-reinforced polymer composites using the rotational moulding process and characterised in terms of morphology and mechanical properties.

Chang, W. C.; Harkin-Jones, E. [School of Mechanical and Aerospace Engineering, Queen's University Belfast, Ashby Building, Stranmillis Road, Belfast BT9 5AH, Northern Ireland (United Kingdom); Kearns, M.; McCourt, M. [Polymer Processing Research Centre, Queen's University Belfast, Ashby Building, Stranmillis Road, Belfast BT9 5AH Northern Ireland (United Kingdom)

2011-05-04

159

Detection of glaucomatous retinal nerve fiber layer damage by scanning laser polarimetry with variable corneal compensation  

NASA Astrophysics Data System (ADS)

One of the earliest signs of glaucoma presence is defects in the retinal nerve fiber layer (RNFL). Scanning laser polarimetry (SLP) provides objective assessment of RNFL, a birefringent tissue, by measuring the total retardation in the reflected light. SLP provides a potential tool for early detection of glaucoma and its progression. The birefringence of the anterior segment of the eye, mainly the cornea, is a confounding variable to SLP's clinical application, if compensation cannot be achieved properly. This paper presents a new SLP system, GDx VCC (Laser Diagnostic Technologies, Inc., San Diego, CA), with a variable corneal compensator (VCC) to achieve individualized corneal compensation. Clinical application of this device in glaucoma detection is also demonstrated.

Zhou, Qienyuan; Reed, Jerry; Betts, Ryan W.; Trost, Peter K.; Lo, Pak-Wai; Wallace, Charles; Bienias, Richard H.; Li, Guoqiang; Winnick, Ross; Papworth, William A.; Sinai, Michael

2003-07-01

160

Use of fibre wastes from production of acetate fibres  

SciTech Connect

The rational use of production wastes is an important part of the Fergana Chemical Fibre Plant in Russia. This recycling reduces the negative effect of the technological process on the environment, increases the economy of production, and produces additional consumer goods. Consumer goods began to be produced at the plant in 1978 with processing of amide-acetate textured fibres into yarn for hand knitting. The need to increase the volumes and expand the variety of goods for the market predetermined an important increase in production of this product. Production of consumer goods has increased since 1990, and both fibre wastes and untreated low-grade fibres and filaments have been used as the starting material. Technological processes for processing wastes and low-grade figured, textured polyamide-acetate fibres into knitting yarn, haberdashery cord, and finishing tape and fringe were created and introduced in subsequent years. The primary technological formulation for production of these materials is well known and is used in light industry. However, production of each type of product in the plant was preceded by research related to selection of the optimum linear density of the filaments used, composition of blends, and the structure of figured fibres, as well as the concrete technological parameters and operating regimes of the equipment to produce articles of the required quality. Development and testing of new decorative textiles are continuing. Low grade and nonstandard acetate semifinished fibre from spinning machines and low grade, bulk dyed acetate fibres have been selected as the raw material for fabrication of these articles.

Askarov, M.I.; Tashpulatova, A.B.

1995-07-01

161

Variable-stiffness composite panels: Buckling and first-ply failure improvements over straight-fibre laminates  

Microsoft Academic Search

One of the primary advantages of using fibre-reinforced laminated composites in structural design is the ability to change the stiffness and strength properties of the laminate by designing the laminate stacking sequence in order to improve its performance. This procedure is typically referred to as laminate tailoring. Traditionally, tailoring is done by keeping the fibre orientation angle within each layer

C. S. Lopes; Z. Gürdal; P. P. Camanho

2008-01-01

162

Modelling of Bird Strike on an Aircraft Wing Leading Edge Made from Fibre Metal Laminates – Part 1: Material Modelling  

Microsoft Academic Search

Fibre Metal Laminates with layers of aluminium alloy and high strength glass fibre composite have been reported to possess excellent impact properties and be suitable for aircraft parts likely to be subjected to impacts from objects such as runway debris or birds. In a collaborative research project, aircraft wing leading edge structures with a glass-based FML skin have been designed,

M. A. McCarthy; J. R. Xiao; N. Petrinic; A. Kamoulakos; V. Melito

2004-01-01

163

Connectorisation of fibre Bragg grating sensors recorded in microstructured polymer optical fibre  

NASA Astrophysics Data System (ADS)

We describe te production and characterization of FC/PC connectorised fibre Bragg grating sensors in polymer fibre. Sensors were recorded in few-moded and single mode microstructured fibre composed of poly (methyl methacrylate).

Abang, A.; Saez-Rodriguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

2013-05-01

164

The future is fibre accelerators  

NASA Astrophysics Data System (ADS)

Could massive arrays of thousands of fibre lasers be the driving force behind next-generation particle accelerators? The International Coherent Amplification Network project believes so and is currently performing a feasibility study.

Mourou, Gerard; Brocklesby, Bill; Tajima, Toshiki; Limpert, Jens

2013-04-01

165

Calcium activation of frog slow muscle fibres  

PubMed Central

1. Skinned muscle fibres were prepared from the tonus bundle of the frog iliofibularis muscle and the contractile response elicited by applied calcium ions was studied. The fibre type was determined by electron microscopy. 2. Fast fibres shortened many times more rapidly than slow fibres, indicating that the slow contraction of slow fibres is an inherent property of the contractile mechanism. 3. The extent of spread of contraction following local calcium application was much greater in slow than in fast fibres, a difference which is consistent with the relative sparsity of the sarcoplasmic reticulum in slow fibres. 4. The ability of the sarcoplasmic reticulum of slow fibres to accumulate calcium was demonstrated by the in situ immobilization of calcium when oxalate solutions were added to the skinned fibre. ImagesPlate 1Plate 2Plate 3Plate 4Plate 5AB

Costantin, L. L.; Podolsky, R. J.; Tice, Lois W.

1967-01-01

166

Continuously tunable fibre attenuator operating in the wavelength range near 1.5 {mu}m  

SciTech Connect

A fibre attenuator is fabricated for the telecommunication wavelength range near 1.5 {mu}m in which a single-mode silica fibre with side polishing is used. The fibre surface is covered by a layer of fluorine-containing polymer with a large thermooptic coefficient. The principle of attenuator operation is based on a change in the conditions of total internal reflection for a guided mode in the polished region due to thermally induced variation in the refractive index of the fluoropolymer layer. The attenuator is insensitive to light polarisation, it has a continuously variable attenuation coefficient in the range 0.2-27 dB, and can be easily incorporated into fibreoptic links. (fibre optics)

Baum, Ol'ga I; Mishakov, Gennadii V; Sokolov, Viktor I [Institute of Laser and Information Technologies, Russian Academy of Sciences, Troitsk, Moscow Region (Russian Federation); Varlamova, Nina V; Zapadinskii, Boris I [N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow (Russian Federation)

2004-09-30

167

Optic disc and retinal nerve fiber layer parameters as indicators of neurodegenerative brain changes in patients with obstructive sleep apnea syndrome.  

PubMed

PURPOSE: Retina is a unique part of the central nervous system (CNS) for visualizing the processes of axonal and neuronal degeneration. Optical coherence tomography (OCT) allows direct visualization and measurement of retinal nerve fiber layer (RNFL) thickness, macular volume, and optic disc (OD) parameters. One of the disorders associated with atrophy in different brain regions is obstructive sleep apnea syndrome (OSAS). In the present study, we aimed to determine OD and RNFL changes measured by OCT for investigating the progress of neurodegeneration development in OSAS, excluding all the other conditions that can directly affect RNFL thickness and optic nerve parameters. METHODS: Both eyes of 101 patients with OSAS and 20 controls were investigated by OCT. Full-night polysomnography (PSG) and ophthalmologic examination including automated visual field (VF) examination and OCT were performed in all of the patients. RESULTS: According to the OSAS grading, patients were grouped as mild (n?=?15), moderate (n?=?27), and severe (n?=?59). We found significant decrease in RNFL thickness only in the patients with severe OSAS compared with the other groups and decreased macular ganglion cell thickness in the severe OSAS group compared with the control group. VF parameters were significantly worsened in all the OSAS subgroups compared to the control group. We found different data such as normal or increased optic nerve parameters as result of subtle OD edema, which may mask possible peripapillar axonal loss. CONCLUSIONS: We think that evaluation of neurodegeneration in OSAS is not always possible by examining OD and RNFL because there are difficulties due to the confounding issues of cerebral atrophy and OD edema. PMID:23636560

Huseyinoglu, Nergiz; Ekinci, Metin; Ozben, Serkan; Buyukuysal, Cagatay; Kale, Murat Yildirim; Sanivar, Hilal Safak

2013-05-01

168

Interfaces with controlled toughness as mechanical fuses to isolate fibres from damage  

Microsoft Academic Search

A source of inadequate performance of metal matrix composites has been the loss of strength due to the reaction layers between\\u000a the fibre and the surrounding metal matrix. Here, we propose that the traditional diffusion barrier coatings on the fibre\\u000a can be utilized to serve as mechanical fuses to isolate the impinging reaction zone cracks by interface delamination. Requirements\\u000a on

V. Gupta; A. S. Argon; J. A. Cornie

1989-01-01

169

Synthesis and characteristics of 80 vol.% tungsten (W) fibre\\/Zr based metallic glass composite  

Microsoft Academic Search

Based on full understanding of wettability between Zr based bulk metallic glass (BMG) matrix and tungsten (W) fibre, and liquid\\/solid interfacial atomic interaction, the high density and high strength 80vol.% W fibre\\/Zr based BMG composite, with optimum interfacial layer, was successfully developed by strictly controlling the infiltration and solidification process. Its density was 17g\\/cm3. The average value of tensile fracture

H. F. Zhang; H. Li; A. M. Wang; H. M. Fu; B. Z. Ding; Z. Q. Hu

2009-01-01

170

Multifunctional, supramolecular, continuous artificial nacre fibres  

NASA Astrophysics Data System (ADS)

Nature has created amazing materials during the process of evolution, inspiring scientists to studiously mimic them. Nacre is of particular interest, and it has been studied for more than half-century for its strong, stiff, and tough attributes resulting from the recognized ``brick-and-mortar'' (B&M) layered structure comprised of inorganic aragonite platelets and biomacromolecules. The past two decades have witnessed great advances in nacre-mimetic composites, but they are solely limited in films with finite size (centimetre-scale). To realize the adream target of continuous nacre-mimics with perfect structures is still a great challenge unresolved. Here, we present a simple and scalable strategy to produce bio-mimic continuous fibres with B&M structures of alternating graphene sheets and hyperbranched polyglycerol (HPG) binders via wet-spinning assembly technology. The resulting macroscopic supramolecular fibres exhibit excellent mechanical properties comparable or even superior to nacre and bone, and possess fine electrical conductivity and outstanding corrosion-resistance.

Hu, Xiaozhen; Xu, Zhen; Gao, Chao

2012-10-01

171

Analysis of nerve fiber layer measurements obtained from scanning laser polarimetry for glaucoma detection  

NASA Astrophysics Data System (ADS)

New analysis tools to address the problem of early detection of the eye blinding disease glaucoma are presented. The thickness maps of the Retinal Nerve Fiber Layer (RNFL) corresponding to 184 eyes (92 Normal and 92 Glaucoma Patients) were obtained from a Scanning Laser Polarimeter (Gdx-VCC). The two dimensional data was used to draw features as opposed to the circular band one-dimensional data in previous approaches. Fourier analysis was performed on the 90° projection of the thickness map data to emphasize the shape contained in the RNFL. Different parameters from the Fourier Coefficients were drawn and tested for their ability to detect glaucoma. Significant differences were found in the shape measures of the projections and the ROC curve analysis was done to measure the separability of the sample set with those features. Another approach was to analyze the shape of the entire 2 dimensional thickness map through a 2D Fourier Transform. A circular ring band (10 pixel wide) data at a radius of 20 pixels was analyzed for this 2D FT. Principal Component Analysis was performed on this data for dimension reduction of feature space. Finally Fisher"s linear discriminant function (LDF) was used as a classifier. The evaluation of different parameters obtained through the Fourier analysis of the thickness map image of RNFL was found to be a useful tool as an analysis strategy for glaucoma detection.

Bhatt, Mittal G.; Rao, Navalgund

2005-04-01

172

Sex-specific differences in retinal nerve fiber layer thinning after acute optic neuritis  

PubMed Central

Objective: The primary objective of this study was to explore the potential influence of gender on recovery from optic neuritis (ON) by determining whether differences in retinal nerve fiber layer (RNFL) thickness can be detected between men and women 6 months after an ON event. Methods: In this prospective cohort study, 39 men and 105 women with acute ON underwent repeat visual and optical coherence tomography (OCT) testing. The main outcome measures were change in RNFL measurements for male and female patients 6 months after ON. Results: Men were older (mean age = 39 years) than women (35 years) (p = 0.05) in this study, and more men (62%) than women (41%) had a diagnosis of relapsing-remitting multiple sclerosis (MS) (p = 0.02). Because age and MS subtype were 2 significant covariates, both variables were controlled for in multiple regression analyses. Other covariates controlled for in the multivariate regression included disease duration (years), use of disease-modifying therapy (yes/no), and use of high-dose corticosteroids for acute ON (yes/no). After 6 months, mean RNFL values were lower in men (74 ?m) than women (91 ?m) (p < 0.001). Men showed more apparent change in RNFL thickness in their ON eyes from baseline to 6 months after ON than women (p = 0.003). Conclusions: There may be differences in recovery between men and women after ON, which can be difficult to detect with conventional visual testing. Our findings raise interesting questions about the potential influence of gender in MS, which may be explored in future studies.

Hodge, William; Pan, Y. Irene; Burton, Jodie M.; Freedman, Mark S.; Stys, Peter K.; Trufyn, Jessie; Kardon, Randy

2012-01-01

173

A review of Australian research into natural fibre cement composites  

Microsoft Academic Search

Over the last three decades considerable research has been committed to finding an alternative fibre to replace asbestos in fibre cement products. Australian research was centred on natural fibres and ultimately it was a natural fibre, wood pulp fibre, that was responsible for the greatest replacement of asbestos in the beleaguered global fibre cement industry.This review reports some of the

Robert S. P. Coutts

2005-01-01

174

Flexural behaviour of small steel fibre reinforced concrete slabs  

Microsoft Academic Search

Influence of length and volumetric percentage of steel fibres on energy absorption of concrete slabs with various concrete strengths is investigated by testing 28 small steel fibre reinforced concrete (SFRC) slabs under flexure. Variables included; fibre length, volumetric percentage of fibres and concrete strength. Test results indicate that generally longer fibres and higher fibre content provide higher energy absorption. The

Ali R. Khaloo; Majid Afshari

2005-01-01

175

Moderate-power cw fibre lasers  

SciTech Connect

A review of the development and investigation of moderate-power (10{sup -1}-10{sup 2} W) cw fibre lasers is presented. The properties of optical fibres doped with rare-earth ions and methods for fabricating double-clad fibres are considered. The methods for fabrication of fibre Bragg gratings used as selective reflectors are discussed and the grating properties are analysed. The main pump schemes for double-clad fibre lasers are described. The properties of fibre lasers doped with neodymium, ytterbium, erbium, thulium, and holmium ions are also considered. The principles of fabrication of Raman converters of laser radiation based on optical fibres of different compositions are discussed and the main results of their studies are presented. It is concluded that fibre lasers described in the review can produce moderate-power radiation at any wavelength in the spectral range from 0.9 to 2 {mu}m. (review)

Kurkov, Andrei S; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2004-10-31

176

Dietary fibre and cardiovascular health.  

PubMed

Cardiovascular disease (CVD) is the leading cause of mortality and morbidity in developed countries. CVD is an inflammatory disease associated with risk factors that include hypercholesterolemia and hypertension. Furthermore, the evolution of this disease depends on the amount of modified lipoproteins (e.g. oxidized) present in the arterial subendothelium. Diet is considered the cornerstone for CVD treatment, as it can lower not only atherogenic lipoprotein levels and degree of oxidation, but also blood pressure, thrombogenesis and concentrations of some relevant factors (e.g. homocystein).Among different diets, the Mediterranean diet stands out due to their benefits on several health benefits, in particular with regard to CVD. Rich in vegetable foods, this diet contributes both quantitatively and qualitatively to essential fibre compounds (cellulose, hemicellulose, gums, mucilages, pectins, oligosaccharides, lignins, etc.). The present paper analyzes the effects of fibre consumption on a) cholesterol and lipoprotein levels; b) systolic and diastolic blood pressures; and c) antioxidant availability and profile. Some studies and meta-analysis are revised, as the possible mechanisms by which fibre may decrease plasma total cholesterol and LDL-cholesterol and blood pressure and to act as antioxidant, as well. In addition, author's own publications regarding the effect of fibre matrix (e.g. seaweeds) on arylesterase and the gene expression of some key antioxidant enzymes are reviewed. The paper also includes data concerning the possible interaction between fibre and some hypolipemic drugs, which may make it possible to attain similar hypolipemic effects with lower dosages, with the consequent decrease in possible side effects. The review concludes with a summary of nutritional objectives related to the consumption of carbohydrates and fibre supplements. PMID:22566302

Sánchez-Muniz, F J

177

Asbestos Fibres in Beverages and Drinking Water  

Microsoft Academic Search

THE hazards of inhaling asbestos fibres1-4, the high incidence of gastrointestinal cancer1,2,5-7 and abdominal neoplasms3,8,9 among asbestos workers and the fact that asbestos fibres may penetrate the mucosa of the stomach and the intestine of animals10,11 are known and so it is important to study the distribution of asbestos fibres in the environment. Asbestos fibres have already been found in

H. M. Cunningham; R. Pontefract

1971-01-01

178

Fibre Composition of Human Intrinsic Tongue Muscles  

Microsoft Academic Search

The muscle fibre composition of three human intrinsic tongue muscles, the longitudinalis, verticalis and transversus, was investigated in four anterior to posterior regions of the tongue using morphological and enzyme- and immunohistochemical techniques. All three muscles typically contained type I, IIA and IM\\/IIC fibres. Type I fibres expressed slow myosin heavy chain (MyHC), type II fibres fast MyHC, mainly fast

P. Stål; S. Marklund; L.-E. Thornell; R. De Paul; P.-O. Eriksson

2003-01-01

179

Thermal conductivity of pitch-derived fibres  

Microsoft Academic Search

The temperature variation of the thermal conductivity of pitch-derived carbon fibres measured from 3 to 300K is reported and discussed. The results are compared with those previously obtained on benzene-derived fibres (BDF) and with the room-temperature thermal conductivity of PAN-based carbon fibres, the GY70. The data confirm that the structure of pitch fibres is less perfect than that of BDF.

B. Nysten; L. Piraux; J.-P. Issi

1985-01-01

180

Surface mechanomyogram reflects muscle fibres twitches summation  

Microsoft Academic Search

The aim of this work is to define the pattern of summation of the muscle fibre twitches in the surface mechanomyogram (MMG) generation process. For this purpose, two groups of muscle fibres of the extensor digitorum communis (EDC) were stimulated using needle electrodes. To these two artificial (because made by different muscle fibre types) motor units (MU1 and MU2), we

Claudio Orizio; Diego Liberati; Cecilia Locatelli; Domenico De Grandis; Arsenio Veicsteinas

1996-01-01

181

Single fibre electromyography in central core disease  

Microsoft Academic Search

Single fibre electromyography in the extensor digitorum communis muscle was studied in five patients with central core disease. The average number of muscle fibre action potentials belonging to the same motor unit was higher in patients than in healthy subjects of the same age. The increase in motor unit fibre density is consistent with increased terminal innervation ratio described in

A. Cruz Martínez; M. T. Ferrer; J. M. López-Terradas; I. Pascual-Castroviejo; P. Mingo

1979-01-01

182

Generation of hollow crystalline tungsten oxide fibres  

NASA Astrophysics Data System (ADS)

Hollow fibres of crystalline W18O49, arranged in a pine-tree-like structure, were generated by heating WS2 powder in oxygen. SEM, TEM, X-ray and electron diffraction studies show that the individual fibres are composed of single-crystal tungsten oxide whiskers. One-dimensional growth, involving heat dissipation along the fibre axis, is proposed.

Hu, W. B.; Zhu, Y. Q.; Hsu, W. K.; Chang, B. H.; Terrones, M.; Grobert, N.; Terrones, H.; Hare, J. P.; Kroto, H. W.; Walton, D. R. M.

183

Carbon Fibre as an Alternative Reinforcing Element  

Microsoft Academic Search

SUMMARY Recently many investigations were made to develop alternative reinforcing elements. Carbon fibres seem to be successful as reinforcing elements in the practical application of structural concrete. An essential aspect of bearing capacity is the bond behaviour of both the carbon fibres (inner bond) and the surrounding concrete. In the following the results of first pull-out tests of carbon- fibres

Holger D. Basche; Nancy Freitag; Karsten Jauck; Balthasar Novák

184

DEVELOPING STANDARDS TO JUDGE FLAX FIBRE QUALITY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Unlike cotton, flax and other bast fibres do not have objective standards for testing or classification. Flax fibres are evaluated and graded within countries or individual companies, but only one test method (ISO 2370 for flax fibre fineness) is recognized on an international level. Marketing of ...

185

Dietary fibre, nuts and cardiovascular diseases  

Microsoft Academic Search

Dietary fibre has a range of metabolic health benefits. Through a variety of mechanisms, dietary fibre, and the viscous variety in particular, slows down gastric emptying and intestinal transit, decreases the rate of intestinal carbohydrate absorption, and increases faecal bile acid excretion. Therefore, consumption of some types of soluble fibre can enhance satiety, which is associated with a lower BMI,

Jordi Salas-Salvadó; Mónica Bulló; Ana Pérez-Heras; Emilio Ros

2006-01-01

186

Skeletal muscle fibre types in the dog.  

PubMed Central

Using a variety of histochemical methods we have investigated the mATPase reaction of skeletal muscle fibres in the dog. Types I, IIA, IIDog (peculiar to the dog) and IIC fibres were identified. The results reveal that the interpretation of the fibre type composition depends on the methods used. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

Latorre, R; Gil, F; Vazquez, J M; Moreno, F; Mascarello, F; Ramirez, G

1993-01-01

187

Occupational ceramic fibres dermatitis in Poland.  

PubMed

Recently, the use of asbestos has been considerably limited in Poland, with the simultaneous increase in the manufacture, processing and application of man-made mineral fibres, which includes ceramic fibres. The aims of this study were (1) to assess the type and frequency of dermal changes caused by the irritant activity of ceramic fibres among workers at the plants that manufacture packing and insulation products; and (2) to compare the irritant activity of Polish-made L-2 and L-3 ceramic fibres with that of the Thermowool ceramic fibres made in England. Workers (n = 226) who were exposed to ceramic fibres underwent dermatological examination. Patch tests with the standard allergen set, together with samples of the fibres L-2, L-3, and Thermowool fibres, were applied to all the workers. It has been shown that the Polish-made L-2 and L-3 fibres differed from Thermowool fibres in that the L-2 and L-3 fibres contained zirconium and were coarser. The proportion of filaments with diameters above 3 microns was 11.1% in the L-3 fibre and 6.3% in the L-2 fibre samples. The Thermowool fibre did not contain filaments thicker than 3 microns. Evident dermal changes, resulting from strong irritant activity of the fibres, were detected in 109 (48.2%) of the workers examined. Irritant contact dermatitis acuta (maculae, sometimes papulae and small crusts on the upper extremities, trunk, and lower extremities), disappearing after 2-3 days, was found in 50 (22.1%) workers. Irritant contact dermatitis chronica (diffuse permanent erythema with numerous telangiectasiae on the lateral portions of the face and neck, on the trunk, behind the auricles) was detected in 40 (17.7%) workers. The remaining 19 (8.4%) workers had both types of dermal change. All examined workers complained of very strong itching. The results of the patch tests confirmed the irritant activity of the ceramic fibres. Erythema without oedema, persisting for up to 96 h, appeared at the places where the fibres had been applied to the skin in 44 (19.5%) workers. In addition, the irritant activity of the fibres has been shown to be correlated with their thickness. The Thermowool fibre was the weakest irritant, because it did not contain filaments above 3 microns in diameter; the L-2 fibre containing 6.3% filaments above 3 microns caused somewhat stronger skin irritation; while the L-3 fibre, which contained 11.1% filaments thicker than 3 microns, was the strongest irritant. A few cases of allergy to nickel, chromium and colophony (rosin) were also detected. PMID:10975132

Kie?-Swierczy?ska, M; Wojtczak, J

2000-07-01

188

A method for estimating the fibre length in fibre-PLA composites.  

PubMed

Wood pulp fibres are an important component of environmentally sound and renewable fibre-reinforced composite materials. The high aspect ratio of pulp fibres is an essential property with respect to the mechanical properties a given composite material can achieve. The length of pulp fibres is affected by composite processing operations. This thus emphasizes the importance of assessing the pulp fibre length and how this may be affected by a given process for manufacturing composites. In this work a new method for measuring the length distribution of fibres and fibre fragments has been developed. The method is based on; (i) dissolving the composites, (ii) preparing the fibres for image acquisition and (iii) image analysis of the resulting fibre structures. The image analysis part is relatively simple to implement and is based on images acquired with a desktop scanner and a new ImageJ plugin. The quantification of fibre length has demonstrated the fibre shortening effect because of an extrusion process and subsequent injection moulding. Fibres with original lengths of >1 mm where shortened to fibre fragments with length of <200 ?m. The shortening seems to be affected by the number of times the fibres have passed through the extruder, the amount of chain extender and the fraction of fibres in the polymer matrix. PMID:23339585

Chinga-Carrasco, G; Solheim, O; Lenes, M; Larsen, A

2013-01-22

189

Segmentation of retinal layers in volumetric OCT scans of normal and glaucomatous subjects  

NASA Astrophysics Data System (ADS)

Volumetric scans of current SD-OCT devices can contain on the order of 50 million pixels. Due to this size and because quantitative measurements in these scans are often needed, automatic segmentation of these scans is required. In this paper, a fully automatic retinal layer segmentation algorithm is presented, based on pixel-classification. First, each pixel is augmented by intensity and gradient data from a local neighborhood, thereby producing a feature vector. These feature vectors are used as inputs for a support vector machine, which classifies each pixel as above or below each interface. Finally, a level set method regularizes the result, producing a smooth surface within the three-dimensional space. Volumetric scans of 10 healthy and 8 glaucomatous subjects were acquired with a Spectralis OCT. Each scan consisted of 193 B-scans, 512 A-lines per B-scan (5 times averaging) and 496 pixels per A-line. Two B-scans of each healthy subject were manually segmented and used to train the support vector machine. One B-scan of each glaucomatous subjects was manually segmented and used only for performance assessment of the algorithm. The root-mean-square errors for the normal eyes were 3.7, 15.4, 15.0 and 5.5 ?m for the vitreous/retinal nerve fiber layer (RNFL), RNFL/ganglion cell layer, inner plexiform layer/inner nuclear layer and retinal pigment epithelium/choroid interfaces, respectively, and 5.5, 11.5, 9.5 and 6.2 ?m for the glaucomatous eyes. Based on the segmentation, retinal and RNFL thickness maps and blood vessel masks were produced.

Vermeer, K. A.; van der Schoot, J.; Lemij, H. G.; de Boer, J. F.

2011-02-01

190

Fibre gratings for hydrogen sensing  

Microsoft Academic Search

Liquid hydrogen has been intensively used in aerospace applications for the past 40 years and is of great interest for future automotive applications. Following major explosive risks due to the use of hydrogen in air, several studies were carried out in order to develop optical fibre sensors for the detection of hydrogen leakage. This paper aims at the presentation of

Alain Trouillet; Emmanuel Marin; Colette Veillas

2006-01-01

191

Fibre gratings for hydrogen sensing  

Microsoft Academic Search

Liquid hydrogen has been intensively used in aerospace applications during the past forty years and is of great interest for future automotive applications. Following upon major explosive risks due to the use of hydrogen in air, several studies were carried out in order to develop optical fibre sensors for the detection of hydrogen leakage. This communication is aimed towards the

Alain Trouillet; Emmanuel Marin; Colette Veillas

2005-01-01

192

Fibre gratings for hydrogen sensing  

NASA Astrophysics Data System (ADS)

Liquid hydrogen has been intensively used in aerospace applications for the past 40 years and is of great interest for future automotive applications. Following major explosive risks due to the use of hydrogen in air, several studies were carried out in order to develop optical fibre sensors for the detection of hydrogen leakage. This paper aims at the presentation of new hydrogen sensors based on the use of fibre Bragg gratings (FBG) and long period gratings (LPG) coated by palladium nanolayers. The sensing principle based on the palladium-hydrogen interaction is presented, as well as experimental results. It is shown that both techniques could be used for hydrogen sensing but with a sensitivity enhanced by a factor up to 500 when using a LPG sensor. FBG sensors appear to be pure strain sensors and LPG sensors are mainly based on the coupling between the cladding modes and evanescent or surface plasmon waves. Preliminary results obtained with an in-fibre Mach-Zehnder interferometer configuration with in-series LPG sensors are also presented. They show potential interest to compensate for the thermal sensitivity of the fibre gratings.

Trouillet, Alain; Marin, Emmanuel; Veillas, Colette

2006-05-01

193

'Fibre Body': The Concept of Fibre in Eighteenth-century Medicine, c.1700-401  

PubMed Central

This paper attempts a comprehensive account of ‘fibre medicine’ elaborated by iatromechanists from c. 1700 to c. 1740. Fibre medicine, a medical theory informed by the notion of the fibre, has been neglected by medical historians despite the pivotal role played by the fibre in animal economy. Referring to a wide range of medical fields such as anatomy, physiology, pathology, therapeutics and life sciences, this paper elucidates the ways that the fibre serves as an indispensable concept for iatromechanists to establish their medical theories. This paper also highlights the metaphorical dimension of the fibre as an integral part of fibre medicine. In re-evaluating the concept of the fibre, this paper seeks to redress the neuro-centric view of eighteenth-century medicine, and attempts to locate the fibre body amidst the fundamental shift from humoralism to solidism.

Ishizuka, Hisao

2012-01-01

194

Relations between the characteristics of Angora rabbit fibre  

Microsoft Academic Search

Angora rabbit fibre is one of the finest specialty animal fibres with its well-known reputation for fineness, lightness and\\u000a softness. This study evaluated the Angora fibre shape and morphology in comparison with Cashmere fibre and wool as well as\\u000a the relation between characteristics of Angora fibre. Unlike other keratinous textile fibres, single Angora fibre composes\\u000a of two sections named as

Levent Onal; Mahmut Korkmaz; Mustafa Tutak

2007-01-01

195

Optical temperature switch based on microstructured fibre filled with different chemical mixtures  

NASA Astrophysics Data System (ADS)

Size, shape and location of the air holes allow to tailor microstructured fibre (MSF) parameters in a very wide range way beyond classical fibres what opens up many possibilities for various applications. Additionally, the propagation parameters of MSF can be actively tuned when the air-holes are filled with different gases, liquids (e.g., liquid crystals) or solid materials (e.g., polymers). The mode confinement in such a filled MSF can be affected by temperature dependent refractive index of material filling the fibre. This idea puts forward a new type of components for creating novel fibre devices such as switches, attenuators and others. Variable optical attenuators (VOAs) play an important role in optical communications as equalizers for dynamic channel power and wavelength division multiplexing in a transmission system. Controlling and monitoring of optical power are also necessary in sensing applications, and especially, in optical systems which require high power laser operation or critical temperature threshold monitoring. Various types of VOA have been developed based on different mechanisms, such as bending loss control, light leaking from the fibre cladding, temperature tuning of the polymer incorporated into the tapered microstructured fibre or electrical tuning of the liquid crystal layers. In this paper we would like to discuss the highly dynamic VOA based on a tuneable microstructured fibre filled with different chemical mixtures used as an on/off temperature switch. Furthermore, the technology of low loss coupling and splicing of the applied MSF with a standard single mode fibre has been developed. Therefore, in the proposed application an optical signal can be transmitted to and from the switch by a standard telecom fibre which considerably reduces transmission losses and allows for the use of standard off-the-shelf components reducing costs of the overall system.

Marc, P.; Piliszek, P.; Murawski, M.; Szymanski, M.; Nasilowski, T.; Jaroszewicz, L. R.

2012-05-01

196

Nanoporous carbon fibres by pyrolysis of nomex polyaramid fibres  

Microsoft Academic Search

Summary The development of porosity upon pyrolysis of Nomex®[poly (m-phenylene isophthalamide)] fibres has been investigated up to a temperature of 1173 K through physical adsorption of N2 (77 K) and CO2 (273 K). The carbonisation temperatures were chosen on the basis of thermal analysis studies (TG and DTA). The results of porous texture characterisation were compared with characteristic features in

J. M. D. Tascón

2005-01-01

197

Modelling of Bird Strike on an Aircraft Wing Leading Edge Made from Fibre Metal Laminates – Part 2: Modelling of Impact with SPH Bird Model  

Microsoft Academic Search

Fibre Metal Laminates with layers of aluminium alloy and high strength glass fibre composite have been reported to possess excellent impact properties and be suitable for aircraft parts likely to be subjected to impacts such as runway debris or bird strikes. In a collaborative research project, aircraft wing leading edge structures with a glass-based FML skin have been designed, built,

M. A. McCarthy; J. R. Xiao; C. T. McCarthy; A. Kamoulakos; J. Ramos; J. P. Gallard; V. Melito

2004-01-01

198

Comparison of Retinal Nerve Fiber Layer Thickness Measurements in Healthy Subjects Using Fourier and Time Domain Optical Coherence Tomography  

PubMed Central

Purpose. To compare the retinal nerve fiber layer (RNFL) measurements using two different ocular coherence tomography (OCT) devices: Cirrus Fourier domain OCT and Stratus time domain OCT. To analyze reproducibility of Fourier domain measurements in healthy subjects. Methods. One hundred and thirty-two eyes of 132 healthy subjects were scaned on the same day with both instruments, separated by 10 minutes from each other. Thickness of quadrant, average and the 12 different areas around the optic nerve were compared between Cirrus and Stratus. Repeatability, intraclass correlation coefficients (ICCs), and coefficients of variation (COVs) were calculated in RNFL measurements provided by Fourier domain device. Results. The average thickness in the optic cube was 95.50??m using Cirrus and 97.85??m using Stratus. Average thickness and temporal quadrant showed significant differences using Cirrus and Stratus methods. Reproducibility was better with Fourier domain OCT (mean COV of 4.54%) than with Stratus time-domain OCT (mean COV of 5.57%). Conclusions. Both scan options give reproducible RNFL thickness measurement, but there are differences between them. Measurements obtained using Fourier domain device show better reproducibility.

Pinilla, Isabel; Garcia-Martin, Elena; Idoipe, Miriam; Sancho, Eva; Fuertes, Isabel

2012-01-01

199

Compounding and mechanical properties of biodegradable hemp fibre composites  

Microsoft Academic Search

Up to now the reinforcing potential of hemp fibres has not been exhausted, as the fibres are bundled and, therefore, a homogenous distribution of fibres and matrix has not been possible. In the present study the fibre bundles used for the composites were degummed by means of biological processes and steam explosion. The degummed fibres, separated into single cells, were

Andreas Keller

2003-01-01

200

The mechanical properties of carbon fibre reinforced Pyrex glass  

Microsoft Academic Search

The mechanical properties of carbon fibre reinforced Pyrex glass are discussed in terms of the volume fraction of fibre, the orientation of the fibres, fibre damage during fabrication, matrix porosity, matrix critical strain, interface properties and the mode of failure in bend tests. The stress at which matrix cracking occurs increases with fibre concentration indicating that the critical strain of

D. C. Phillips; R. A. J. Sambell; D. H. Bowen

1972-01-01

201

Resistance of fibre concrete slabs to low velocity projectile impact  

Microsoft Academic Search

An investigation on fibre concrete slabs subjected to low velocity projectile impact was carried out to assess impact resistance. The main variables of the study were type of fibre and volume fraction of fibres. The types of fibres chosen were polyolefin, polyvinyl alcohol and steel. The volume fraction of fibres examined were 0%, 1% and 2%. A total of 10

K. C. G Ong; M Basheerkhan; P Paramasivam

1999-01-01

202

Emerging Optical Fibre Technologies with Potential Defence Applications  

NASA Astrophysics Data System (ADS)

Recent years have seen the development of a range of promising optical fibre technologies emerge, enabled by advances in materials and fabrication techniques. We describe 3 emerging areas in optical fibre developments: nanomechanical optical fibres, microstructured hollow core silica fibres for high peak optical power and/or extended infrared transmission, and chalcogenide glasses and fibres for mid-IR applications.

Loh, Wei H.; Hewak, Dan; Petrovich, Marco N.; Hayes, John R.; Stewart, Will; Clarkson, Andy

2012-09-01

203

Bend effects on fibre Bragg gratings in standard and low bend loss optical fibres  

Microsoft Academic Search

Summary The effects of relatively small bend diameters on fibre Bragg gratings written in standard and low bend loss fibre have been investigated. Results including Bragg wavelength shifts with bending are reported.

Alexander C. Thompson; William G. A. Brown; Paul R. Stoddart; Scott A. Wade

2010-01-01

204

32-QAM radio transmission over multimode fibre beyond the fibre bandwidth  

Microsoft Academic Search

We show for the first time that radio frequency transmission over multimode fibre beyond the fibre bandwidth is a practical option for distributed antenna systems. 32-QAM transmission at 2 GHz is performed with negligible penalty.

D. Wake; S. Dupont; J.-P. Vilcot; A. J. Seeds

2002-01-01

205

Retinal nerve fiber layer thickness remains unchanged following laser-assisted in situ keratomileusis 1 1 The authors have no financial interest in any device or technique described in this paper  

Microsoft Academic Search

PURPOSE: To evaluate the effect of laser-assisted in situ keratomileusis (LASIK) on retinal nerve fiber layer (RNFL) thickness measurements obtained with scanning laser polarimetry (SLP), optical coherence tomography (OCT), and scanning laser tomography (SLT).DESIGN: Interventional case series.METHODS: Twenty eyes (20 patients) undergoing LASIK were enrolled in this prospective study. SLP, OCT, and SLT examinations were performed 1 week prior to

Rabia Gürses-Özden; Jeffrey M Liebmann; Danilo Schuffner; Douglas F Buxton; Barrie D Soloway; Robert Ritch

2001-01-01

206

Motor unit fibre density in the extensor digitorum communis muscle. Single fibre electromyographic study in normal subjects at different ages  

Microsoft Academic Search

A single fibre EMG study is presented from extensor digitorum communis muscle in sujbects aged 10 to 89 years. The average number of single muscle fibre action potentials generated by muscle fibres in the same motor unit within the uptake area of the electrode is used as a measure of the motor unit fibre density. The fibre density increases slowly

E Stålberg; B Thiele

1975-01-01

207

Engineering and evaluation of hemp fibre reinforced polypropylene composites: Fibre treatment and matrix modification  

Microsoft Academic Search

Hemp fibres were alkali treated to improve their suitability for use as reinforcements in composite materials. Improvements in tensile strength, Young’s modulus, fibre separation, crystallinity index, lignin reduction and thermal stability were observed for hemp fibres treated with a solution of 5wt% NaOH\\/2wt% Na2SO3. A range of hemp fibre reinforced polypropylene composites were produced by extrusion and injection moulding, and

G. W. Beckermann; K. L. Pickering

2008-01-01

208

A fibre optic corrosion fuse sensor using stressed metal-coated optical fibres  

Microsoft Academic Search

A novel optical fibre-based corrosion sensor based on the mechanical failure of stressed metal-coated optical fibres when exposed to a corrosive environment is presented. The current work discusses proof-of-principle tests carried out using commercially available aluminium-coated optical fibres. Tests have been undertaken in a non-corrosive environment, in aqua regia and in sea water. The failure times of stressed aluminium-coated fibres

S. A. Wade; C. D. Wallbrink; G. McAdam; S. Galea; B. R. W. Hinton; R. Jones

2008-01-01

209

Yb3+-Doped Double-Clad Fibre Laser Based on Fibre Bragg Grating  

Microsoft Academic Search

A novel Yb3+-doped double-clad fibre laser based on a double-clad fibre Bragg grating is presented. The fibre Bragg grating, as the output mirror, has been formed in Yb3+-doped double-clad fibre with the phase-mask method. When the input pump power is 2.8 W, the maximum laser output power is 570 mW, with <0.2 nm in line-width at the wavelength of 1.058

Wan-De Fan; Sheng-Gui Fu; Qiang Zhang; Ding Ning; Li-Jun Li; Zhi Wang; Shu-Zhong Yuan; Xiao-Yi Dong

2003-01-01

210

Ytterbium-doped fibre laser with a Bragg grating reflector written in a multimode fibre  

SciTech Connect

An efficient cladding-pumped Yb-doped fibre laser with a Bragg grating written in a multimode graded-index fibre is fabricated for the first time. The laser emits one transverse mode with a slope efficiency of 60%. The resonator design proposed in the paper can be used for the development of high-power fibre lasers with an increased fibre core diameter. (lasers)

Kurkov, Andrei S; Grukh, Dmitrii A; Medvedkov, O I; Paramonov, Vladimir M; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2005-04-30

211

Spun elliptically birefringent photonic crystal fibre.  

PubMed

Elliptically birefringent fibre has been fabricated by spinning the preform of a highly linearly birefringent photonic crystal fibre (PCF) during the drawing process. The resulting Spun Highly Birefringent (SHi-Bi) PCF offers intrinsic sensitivity to magnetic fields through the Faraday effect without the high inherent temperature sensitivities suffered by conventional spun stress birefringence fibres. The ellipticity of the birefringence has been measured and temperature independence has been demonstrated. PMID:19532419

Michie, Andrew; Canning, John; Bassett, Ian; Haywood, John; Digweed, Katja; Aslund, Mattias; Ashton, Brian; Stevenson, Michael; Digweed, Justin; Lau, Alfred; Scandurra, Daniel

2007-02-19

212

Large-scale fibre-array multiplexing  

SciTech Connect

The possibility of creating a fibre multiplexer/demultiplexer with large-scale multiplexing without any basic restrictions on the number of channels and the spectral spacing between them is shown. The operating capacity of a fibre multiplexer based on a four-fibre array ensuring a spectral spacing of 0.7 pm ({approx} 10 GHz) between channels is demonstrated. (laser applications and other topics in quantum electronics)

Cheremiskin, I V; Chekhlova, T K [Department of Radiophysics, Peoples' Friendship University of Russia, Moscow (Russian Federation)

2001-05-31

213

Photonic crystal fibres for lasers and amplifiers  

NASA Astrophysics Data System (ADS)

Air Silica microstructure fibres, often improperly named Photonic Crystal Fibres (PCFs), offer singular propagation properties because of the multiple possible interactions between the guided fields and the heterogeneous structure. We propose a short review of the various PCFs fields of applications while showing, through various examples of fibre structures, how these properties are exploited and which are the most significant results. To cite this article: Ph. Roy et al., C. R. Physique 7 (2006).

Roy, Philippe; Leproux, Philippe; Février, Sébastien; Pagnoux, Dominique; Auguste, Jean-Louis; Blondy, Jean-Marc; Hilaire, Stéphane; Lavoute, Laure; Jamier, Raphael; Desfarges-Berthelemot, Agnès; Kermène, Vincent; Restoin, Christine

2006-03-01

214

Pseudodifferential operators on manifolds with fibred boundaries  

Microsoft Academic Search

Let $X$ be a compact manifold with boundary. Suppose that the boundary is fibred, $\\\\phi:\\\\pa X\\\\longrightarrow Y,$ and let $x\\\\in\\\\CI(X)$ be a boundary defining function. This data fixes the space of `fibred cusp' vector fields, consisting of those vector fields $V$ on $X$ satisfying $Vx=O(x^2)$ and which are tangent to the fibres of $\\\\phi;$ it is a Lie algebra and

Rafe Mazzeo; Richard B. Melrose

1998-01-01

215

Phosphate Glass Fibre Composites for Bone Repair  

Microsoft Academic Search

We investigate high-modulus degradable materials intended to replace metals in biomedical applications. These are typically composites comprising a polylactide (PLA) matrix reinforced with phosphate glass fibres, which provide reinforcement similar to E-glass but are entirely degradable in water to produce, principally, calcium phosphate. We have made composites using a variety of fibre architectures, from non-woven random mats to unidirectional fibre

Andrew J. Parsons; Ifty Ahmed; Papia Haque; Ben Fitzpatrick; Muhammad I. K. Niazi; Gavin S. Walker; Chris D. Rudd

2009-01-01

216

Cellulose modified fibres in cement based composites  

Microsoft Academic Search

The objective of the present work is to evaluate the effect of surface modification of cellulose pulp fibres on the mechanical and microstructure of fibre–cement composites. Surface modification of the cellulose pulps was performed with Methacryloxypropyltri-methoxysilane (MPTS) and Aminopropyltri-ethoxysilane (APTS) in an attempt to improve their durability into fibre–cement composites. The surface modification showed significant influence on the microstructure of

G. H. D. Tonoli; U. P. Rodrigues Filho; H. Savastano Jr.; J. Bras; M. N. Belgacem; F. A. Rocco Lahr

2009-01-01

217

Properties of carbon fibre-polymer interfaces  

Microsoft Academic Search

Two types of sized carbon fibre were used in this study, Besfight HTA-7-12000 and Besfight ST-III-7-6000, both from Toho Rayon Co. Some of the fibres were thoroughly washed in chloroform at room temperature to remove the epoxy sizing. The unsized carbon fibres, Hysol XA-S, were from Hysol Inc. The curing agents for di-glycidylether of bisphenol-A (Epon 828, Shell Chemical Co.)

Yin-Tyan Liao; I-Chung Tung

1991-01-01

218

Sensing applications of photonic crystal fibres  

NASA Astrophysics Data System (ADS)

Fast, frequent, accurate and reliable measurements of physical factors such as temperature, stress or strain play a key role when it comes to ensuring the smooth operation of processes in many domestic, commercial and industrial constructions or devices. For example, most fabrication devices and production process rely on temperature and stress measurements to operate; and most large buildings depend on a series of temperature sensors to control the heating or cooling to maintain the temperature. Photonic crystal fibres (PCF), constitute a class of optical fibres, which has a large potential for number of novel applications either in the telecom or in the sensing domain. Analysis of sensing characteristics of different photonic crystal fibre structures, including effective index and mode field distribution, photonic bandgap, chromatic dispersion, phase and group modal birefringence, confinement and bending losses, sensitivity to temperature, hydrostatic pressure, and other physical parameters are revealed. The benefits of PCF allow fabrication of different types of specialty microstructured fibres such as endlessly single mode, double clad, germanium or rare earth doped, highly birefringent, and many other microstructured fibres as sensor components. The developed characterization techniques of specialty microstructured fibres are reviewed as well. Finally, the new microstructured fibres and fibre component for sensing applications which were designed, fabricated and characterized will be presented. One of the demonstrated components is the effective Bragg grating written in highly birefringent and single mode photonic crystal fibre.

Nasilowski, Tomasz; Statkiewicz, Gabriela; Szpulak, Marcin; Olszewski, Jacek; Golojuch, Grzegorz; Martynkien, Tadeusz; Urbanczyk, Waclaw; Mergo, Pawel; Makara, Mariusz; Wojcik, Jan; Van Erps, Jurgen; Vlekken, Johan; Chojetzki, Christoph; Berghmans, Francis; Thienpont, Hugo

2007-05-01

219

Durability under fatigue loading of optical fibres applied to fibre reinforced plastic composites  

Microsoft Academic Search

This paper summarises ongoing research conducted at the Cooperative Research Centre for Advanced Composite Structures (CRC-ACS) on the durability to fatigue loading of optical fibre sensors, which were surface mounted or embedded in fibre reinforced plastic composites. The objective of the research is to quantify the parameters affecting the fatigue performance of such optical fibres. Signal degradation of surface mounted

Israel Herszberg; Michael K. Bannister; Henry C. H. Li; Ben Qi; Jane Marsden

2007-01-01

220

Mechanical properties of hemp fibre reinforced cement: Influence of the fibre\\/matrix interaction  

Microsoft Academic Search

In this paper, preliminary results about both the chemical and physical behaviours of hemp fibres in calcium rich medium are presented. The influence of hemp fibres introduction in Portland cement pastes on the setting time has been investigated. It seems that pectin contained in the fibres can form complex molecules with calcium ions and could be responsible for the observed

D. Sedan; C. Pagnoux; A. Smith; T. Chotard

2008-01-01

221

Tensile and compressive properties of flax fibres for natural fibre reinforced composites  

Microsoft Academic Search

Mechanical properties of standard decorticated and hand isolated flax bast fibres were determined in tension as well as in compression. The tensile strength of technical fibre bundles was found to depend strongly on the clamping length. The tensile strength of elementary flax fibres was found to range between 1500 MPa and 1800 MPa, depending on the isolation procedure. The compressive

H. L. Bos; M. J. A. Van Den Oever; O. C. J. J. Peters

2002-01-01

222

Preparation of C-fibre borosilicate glass composites: Influence of the fibre distribution on mechanical properties  

Microsoft Academic Search

Optimum conditions with respect to preparation-determined fibre distribution in borosilicate glass composites were investigated. Continuous C-fibre bundles were impregnated with glass powder in silicon alkoxide solution and wound in parallel to prepregs which were hot pressed into unidirectional composites. The influence of the glass particle size during the impregnation of fibre bundles and during hot pressing on the homogeneity of

T. Klug; R. Brückner

1994-01-01

223

Tropical fibre sources for pigs—digestibility, digesta retention and estimation of fibre digestibility in vitro  

Microsoft Academic Search

The digestibility of high-fibre diets and digesta passage was measured in growing pigs and attempts were made to predict the in vivo digestibility from in vitro data. In Experiment 1, six diets were formulated to measure digestibility using low-fibre cassava starch, fish meal and soya bean meal in combination with six locally available fibre sources. Four green plants: banana sheaths

Nguyen Nhut Xuan Dung; Luu Huu Manh; Peter Udén

2002-01-01

224

Fabrication of highly efficient fibre-optic gas sensors using SiO2\\/polymer nanoporous thin films  

Microsoft Academic Search

A highly porous nano-thin film has been deposited on the optical fibre with the aim to develop a fibre-optic gas sensor. The film was composed of alternate layers of poly(diallyldimethyl ammonium chloride) (PDDA) and silica nanoparticles of 40-50 nm in diameter deposited using the electrostatic self assembly process. As a final step of preparation, the coating was infused with the

Suguru Kodaira; Sergiy Korposh; Seung-Woo Lee; William J. Batty; Stephen W. James; R. P. Tatam

2008-01-01

225

Tow-Placed, Variable-Stiffness Composite Panels: Damage Tolerance Improvements over Traditional Straight-Fibre Laminates  

Microsoft Academic Search

One of the primary advantages of using fibre-reinforced laminated composites in structural design is the ability to change\\u000a the stiffness and strength properties of the laminate by designing the laminate stacking sequence in order to improve its\\u000a performance. This procedure is typically referred to as laminate tailoring. Traditionally, tailoring is done by keeping the\\u000a fibre orientation angle within each layer

Cláudio S Lopes; Zafer Gürdal; Pedro P. Camanho

226

Efficient non-linear optical fibres and their applications  

Microsoft Academic Search

There seem to be three possible approaches to achieve efficient non-linear optical effects in fibres: the increase of optical intensity in fibres, the control of group velocity dispersion in fibres and the use of efficient non-linear optical materials for fibres. From this viewpoint, high-numerical-aperture single-mode fibres with high optical intensity, single-mode fibres with extremely small dispersion at the operating wavelength

S. Sudo; H. Itoh

1990-01-01

227

Simulation of complex phenomena in optical fibres  

NASA Astrophysics Data System (ADS)

Optical fibres are essential for many types of highly multiplexed and precision spectroscopy. The success of the new generation of multifibre instruments under construction to investigate fundamental problems in cosmology, such as the nature of dark energy, requires accurate modellization of the fibre system to achieve their signal-to-noise ratio (SNR) goals. Despite their simple construction, fibres exhibit unexpected behaviour including non-conservation of etendue (focal ratio degradation, FRD) and modal noise. Furthermore, new fibre geometries (non-circular or tapered) have become available to improve the scrambling properties that, together with modal noise, limit the achievable SNR in precision spectroscopy. These issues have often been addressed by extensive tests on candidate fibres and their terminations, but these are difficult and time-consuming. Modelling by ray tracing and wave analysis is possible with commercial software packages, but these do not address the more complex features, in particular FRD. We use a phase-tracking ray-tracing method to provide a practical description of FRD derived from our previous experimental work on circular fibres and apply it to non-standard fibres. This allows the relationship between scrambling and FRD to be quantified for the first time. We find that scrambling primarily affects the shape of the near-field pattern but has negligible effect on the barycentre. FRD helps to homogenize the near-field pattern but does not make it completely uniform. Fibres with polygonal cross-section improve scrambling without amplifying the FRD. Elliptical fibres, in conjunction with tapering, may offer an efficient means of image slicing to improve the product of resolving power and throughput, but the result is sensitive to the details of illumination. We also investigated the performance of fibres close to the limiting numerical aperture since this may affect the uniformity of the SNR for some prime focus fibre instrumentation.

Allington-Smith, Jeremy; Murray, Graham; Lemke, Ulrike

2012-12-01

228

Structural behaviour of fibre metal laminates subjected to a low velocity impact  

NASA Astrophysics Data System (ADS)

Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile impact, which produced the corresponding load-displacement traces and deformation/failure modes for the validation of numerical models. Finite element (FE) models were then developed to simulate the impact behaviour of FMLs tested. The aluminium (alloy grade 2024-0) layer was modelled as an isotropic elasto-plastic material up to the on-set of post failure stage, followed by shear failure and tensile failure to simulate its failure mechanisms. The glass fibre laminate (woven glass-fibre reinforced composite) layer was modelled as an orthotropic material up to its on-set of damage, followed by damage initiation and evolution using the Hashin criterion. The damage initiation was controlled by failure tensile and compressive stresses within the lamina plane which were primarily determined by tests. The damage evolution was controlled by tensile/compressive fracture energies combined with both fibre and matrix. The FE models developed for the 2/1, 3/2 and 4/3 FMLs plates made with 4-ply and 8-ply glass fibre laminate cores were validated against the corresponding experimental results. Good correlation was obtained in terms of load-displacement traces, deformation and failure modes. The validated models were ready to be used to undertake parametric studies to cover FMLs plates made with various stack sequences and composite cores.

Fan, JiYing; Guan, ZhongWei; Cantwell, W. J.

2011-06-01

229

Gene expression in developing fibres of Upland cotton (Gossypium hirsutum L.) was massively altered by domestication  

Microsoft Academic Search

BACKGROUND: Understanding the evolutionary genetics of modern crop phenotypes has a dual relevance to evolutionary biology and crop improvement. Modern upland cotton (Gossypium hirsutum L.) was developed following thousands of years of artificial selection from a wild form, G. hirsutum var. yucatanense, which bears a shorter, sparser, layer of single-celled, ovular trichomes ('fibre'). In order to gain an insight into

Ryan A Rapp; Candace H Haigler; Lex Flagel; Ran H Hovav; Joshua A Udall; Jonathan F Wendel

2010-01-01

230

Hybrid modeling of woven fibre reinforced metal matrix composite for multilayer circuit boards  

Microsoft Academic Search

Purpose – To present a method to model woven fibre reinforced metal matrix composite for multilayer circuit boards. Design\\/methodology\\/approach – This paper presents a hybrid modelling method to model multilayer multimaterial composites with the combination of metallic and woven composite plies. Firstly, 3D unit cells of woven composite are idealized as orthotropic plies, while metallic layers are taken as isotropic

K. H. Low; Yuqi Wang

2008-01-01

231

Polarisation effects in twin-core fibre: Application for mode locking in a fibre laser  

SciTech Connect

We report the first measurements of the longitudinal power distribution in a twin-core optical fibre at different input light polarisations. Experimental evidence is presented that, because of the difference in birefringence between the cores, the power in them depends on which core the beam is launched into. Experimental data are interpreted in terms of a modified polarisation model for mode coupling in twin-core fibres which takes into account the birefringence of the cores. In addition, we demonstrate for the first time the use of the polarisation properties of a twincore fibre for mode locking in a fibre laser. (optical fibres, lasers and amplifiers. properties and applications)

Lobach, I A; Kablukov, S I; Podivilov, Evgenii V; Babin, Sergei A; Apolonski, A A

2012-09-30

232

DESIGN NOTE: Birefringence monitoring of a Hi-Bi fibre under chemical etching through a fibre loop mirror  

NASA Astrophysics Data System (ADS)

Birefringence monitoring of a Hi-Bi fibre under chemical etching is conducted. The Hi-Bi fibre (a bow-tie type) was inserted in a fibre loop mirror and the optical spectral response was measured while chemical etching of the Hi-Bi fibre was taking place. The birefringence of the bow-tie fibre has decreased due to the etching and the wavelength spacing of the fringe minima of the fibre loop mirror has increased.

Frazão, O.; Guerreiro, A.; Santos, J. L.; Baptista, J. M.

2007-12-01

233

Packaging of optical Fibre Bragg Gratings  

Microsoft Academic Search

Fibre Bragg Gratings (FBGs) are all-fibre optical filters with applications in sensing and telecommunication systems. The packaging of FBGs offers many challenges to the manufacturer as stringent tolerances for wavelength stability of the filter over widely varying environmental operating conditions are required for state of the art Dense Wavelength Division Multiplexing (DWDM) telecommunication systems. This paper presents various processes and

D. C. Psaila; H. G. Inglis

2001-01-01

234

Muscle fibre type and meat quality  

Microsoft Academic Search

Muscle morphology and fibre type composition are briefly reviewed in relation to colour stability and tenderness in beef, and water holding capacity, colour and eating quality in pork. A large inter-muscle and inter-animal variation exists in meat quality, which is often related to metabolic and contractile properties as determined by their muscle fibre type distribution. Characteristics of different muscles may

R. E. Klont; L. Brocks; G. Eikelenboom

1998-01-01

235

THE SATELLITE CELL OF SKELETAL MUSCLE FIBRES  

Microsoft Academic Search

Satellite cells of adult skeletal muscle fibres are myogenic monoculeated cells that are closely attached to muscle fibres. These cells provide new myonuclei during growth and regeneration; myonuclei are postmitotic. Three to 11 of myonuclei seen by light microscopy in reality are satellite cell nuclei. Developing muscles contain up to 35% satellite cells. Their incidence decreases after denervation and possibly

Henning Schmalbruch

2006-01-01

236

Progress in silica optical fibre photosensitivity  

Microsoft Academic Search

A comprehensive survey of photosensitivity in silica optical fibre is reviewed. Recent work on understanding the mechanisms\\u000a contributing to germanium or aluminum doped fibre photosensitivity is discussed within the framework of the colour-center\\u000a or photoelastic densification models.

Marc Douay; Wen Xiang XIé; Bruno Leconte; Thierry Taunay; Pascal Bernage; Pierre Niay; Patrick Cordier; Jean-François Bayon; Hubert Poignant; Eric Delevaque

1997-01-01

237

Maleated coupling agents for natural fibre composites  

Microsoft Academic Search

Maleated coupling agents are widely used to strengthen composites containing fillers and fibre reinforcements. The established role of MaPOs results from two main factors, economical manufacturing and the efficient interaction of maleic anhydride with the functional surface of fibre reinforcements. Peak performance was demonstrated in agrofibre polypropylene composites by selecting a maleated coupler that has the appropriate balance of molecular

T. J. Keener; R. K. Stuart; T. K. Brown

2004-01-01

238

Alternative Dopants for Silica Fibre Amplifiers  

Microsoft Academic Search

Optical telecommunications systems benefit from well developed and efficient optical fibre amplifiers operating on relatively narrow bands. Recent improvements in silica fibres broadened their transmission window, allowing telecommunications almost anywhere within the 800 - 1700 nm window. Although already available amplified bandwidth is not fully used yet, long term basic research is needed to identify innovative, cheap, reliable fiber amplifiers

B. Dussardier; W. Blanc

2007-01-01

239

On the fine structure of bamboo fibres  

Microsoft Academic Search

The thick-walled bamboo fibres exhibit a polylamellate structure with alternating broad and narrow lamellae. Characteristically the cellulose fibrils in the broad lamellae are oriented almost parallel to the longitudinal axis of the fibre (2–20°), whereby there is a gradual but only slight increase in the angle from middle lamella to lumen. The narrow lamellae consist of fibrils oriented almost perpendicular

N. Parameswaran; W. Liese

1976-01-01

240

The fractography of thermoplastic textile fibres  

Microsoft Academic Search

The use of a scanning electron microscope in studying the fractography of fibres is described and its advantages explained. A common pattern of break is shown for thermoplastic fibres at extension rates up to 8×10-2 sec-1. This involves a slow crack which becomes catastrophic at the critical crack length. The critical crack length depends upon the rate of extension, and

J. W. S. Hearle; P. M. Cross

1970-01-01

241

The fatigue behaviour of Kevlar-29 fibres  

Microsoft Academic Search

Single Kevlar-29 fibres have been subjected to a variety of tensile cyclic and steady loading conditions. The dispersion of tensile strengths of the samples tested was found to be inherent to the fibre due to the distribution of defects in it and not due to variations of diameter between samples. Cyclic loading was found to produce both longer and shorter

M. H. Lafitte; A. R. Bunsell

1982-01-01

242

A review of optical fibre radiation dosimeters  

Microsoft Academic Search

Purpose – The purpose of this paper is to provide a detailed review of radiation dosimetry techniques based on optical fibre dosimeters. It presents a comprehensive bibliography of the current research activities in the area. Design\\/methodology\\/approach – A range of published work on optical fibre radiation dosimeters are presented, with the merits and limitations discussed. Each radiation dosimetry technique is

S. OKeeffe; C. Fitzpatrick; E. Lewis; A. I. Al-Shamma'a

2008-01-01

243

Thermostabilization of Vidlon polycaproamide tire cord fibres  

Microsoft Academic Search

In spite of the good results which have been obtained in the thermostabilization of polycaproamide (PCA) fibres, this problem still cannot be considered solved: The thermostabilizers proposed by various companies do not give the expected effect in all technologies of PCA fibre preparation. This is explained by the need to introduce the thermostabilizers at a strictly determined point in the

N. P. Gankov; Ts. P. Kapralyakov; P. I. Filipov; E. P. Stanev

1982-01-01

244

A wavelength encoded rotary displacement fibre sensor  

Microsoft Academic Search

An improved design for a fibre optic rotary encoder is described in which a Gray code disc is used to encode angular displacement information on a broadband spectrum. Broadband light from a halogen lamp is brought to the encoder by an input fibre positioned in the focal plane of an aspheric lens. A diffraction grating disperses the collimated beam of

M. Maghoo

1994-01-01

245

Assessment of rates of structural change in glaucoma using imaging technologies  

PubMed Central

Purpose To review the ability of current imaging technologies to provide estimates of rates of structural change in glaucoma patients. Patients and methods Review of literature. Results Imaging technologies, such as confocal scanning laser ophthalmoscopy (CSLO), scanning laser polarimetry (SLP), and optical coherence tomography (OCT), provide quantifiable and reproducible measurements of the optic disc and parapapillary retinal nerve fibre layer (RNFL). Rates of change as quantified by the rim area (RA) (for CSLO) and RNFL thickness (for SLP and OCT) are related to glaucoma progression as detected by conventional methods (eg, visual fields and optic disc photography). Evidence shows that rates of RNFL and RA loss are significantly faster in progressing compared with non-progressing glaucoma patients. Conclusion Measurements of rates of optic disc and RNFL change are becoming increasingly precise and individualized. Currently available imaging technologies have the ability to detect and quantify progression in glaucoma, and their measurements may be suitable end points in glaucoma clinical trials.

Mansouri, K; Leite, M T; Medeiros, F A; Leung, C K; Weinreb, R N

2011-01-01

246

EDITORIAL: Optical Fibre Sensors 18 (OFS-18)  

NASA Astrophysics Data System (ADS)

The International Conference on Optical Fibre Sensors (OFS-18) was held in October 2006 in Cancún, Mexico, under the general chairmanship of Dr Alexis Mendez (MCH Engineering LLC, USA) and Dr Fernando Mendoza (Centro de Investigaciones en Optica, Mexico). 'OFS', as it has become known, is firmly established as the leading international conference for the optical fibre sensor community. Since its inception, in London in 1983, and under the leadership of an international steering committee independent of any learned society or professional institution, it has been held approximately every eighteen months. The venue nominally rotates from Europe, to the Americas, and thence to Asia and the Pacific. OFS-18 demonstrated the continuing vigour of the community, with some 250 papers presented, plus two workshops, with attendance as international as ever. In recent years, it has become a tradition to publish a post-conference special issue in the journal Measurement Science and Technology, and these special issues offer a representative sample of the current status of the field. In the nearly 25 years since OFS began, many of the early ideas and laboratory-based proof-of-principle experiments have led to highly developed instrumentation systems, and to successful commercial products. Perhaps the most mature of all of these technologies is the optical fibre gyroscope, with the fibre hydrophone a close second—originally developed for defence applications for which it is now established, but with increasing relevance to the oil and gas industry; electromagnetic sensors based on the Faraday and electro-optic effects are of growing significance in the power generation and distribution industry; whilst in-fibre grating-based sensors occupy an expanding niche in structural monitoring, especially in civil engineering. It is therefore appropriate that the first day of OFS was devoted to workshops on structural health monitoring, and to commemorate the 30th anniversary of the fibre optic gyroscope, conventionally taken to date from the first experimental demonstration by V Vali and R W Shorthill (1976 'Fibre ring interferometer' Appl. Opt. 15 1099-100). It is an indication of the health of the community that the successful maturity of some applications is complemented by the new technologies that will be the basis of the future development of the field, and here the content of this special issue is an interesting indication of likely areas of growth. Essentially all current fibre optic systems are based on solid, doped fused silica fibres, which are the basis of the world's telecommunications industry. However, over the last decade an exciting development has been micro-structured fibres, whose waveguiding properties owe as much to the structure of the fibre as to the materials from which they are made. The significance for sensing applications is considerable, with opportunities to achieve properties for dispersion, environmental sensitivity, wavelength range and power-handling quite different from the capabilities of conventional fibre. Thus it is not surprising that several of the papers in the issue (by Cordeiro, Martynkien, Bock, Wolinski, Michie, Digonnet and Kilic) are devoted to applications of such fibres—photonic crystal fibres (PCF), as they are often called. Digonnet's contribution is especially interesting, being concerned with the use of hollow-core photonic bandgap fibre to form a gyroscope, hence avoiding the many subtle non-linear optical effects that can degrade the performance of a conventional fibre gyroscope. PCF are not the only special fibres to feature in the issue: polymer fibres are of increasing interest for sensing applications (O'Keeffe, Kiesel, Kalli and Ashley), not least for their ability to withstand high levels of strain. In-fibre gratings continue to be a very important area in the field, and are well represented in the issue (Ni, González-Segura, Chen, Falate, Kamikawachi, Wang and Correia). We hope that this special issue helps to further developments in the field of optical fibre sensors and we w

Jones, Julian D. C.; Tatam, Ralph P.

2007-10-01

247

Erbium-doped aluminophosphosilicate optical fibres  

SciTech Connect

We have studied the active properties of erbium-doped aluminophosphosilicate (APS) core fibres in wide ranges of erbia, alumina and phosphorus pentoxide concentrations. The absorption and luminescence spectra of the P{sub 2}O{sub 5}- or Al{sub 2}O{sub 3}-enriched erbium-doped APS fibres are shown to be similar to those of the erbium-doped fibres singly doped with phosphorus pentoxide or alumina, respectively. The formation of AlPO{sub 4} in APS fibres leads not only to a reduction in the refractive index of the glass but also to a marked increase in Er{sub 2}O{sub 3} solubility in silica. (optical fibres)

Likhachev, M E; Bubnov, M M; Zotov, K V; Medvedkov, O I [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Lipatov, D S; Yashkov, M V; Gur'yanov, Aleksei N [Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

2010-09-10

248

Supercontinuum generation in thulium-doped fibres  

SciTech Connect

Supercontinuum generation in thulium-doped fibres under pumping at 1.59 {mu}m is investigated. Amplification of supercontinuum in the range of 1.8--2.0 {mu}m is found for a fibre doped to a level of 2 Multiplication-Sign 10{sup 19} cm{sup -3}. For a fibre with an activator concentration of 2 Multiplication-Sign 10{sup 20} cm{sup -3} amplification is also observed in the (2.1 - 2.45)-{mu}m band, which suggests the occurrence of the {sup 3}H{sub 4} {yields} {sup 3}H{sub 5} optical transition in the fibre. The occupation of the {sup 3}H{sub 4} level can be explained by cooperative effects. (optical fibres, lasers and amplifiers. properties and applications)

Kurkov, Andrei S; Kamynin, V A; Tsvetkov, V B; Sadovnikova, Ya E; Marakulin, A V; Minashina, L A

2012-09-30

249

Spectral Domain Optical Coherence Tomography in Glaucoma: Qualitative and Quantitative Analysis of the Optic Nerve Head and Retinal Nerve Fiber Layer (An AOS Thesis)  

PubMed Central

Purpose: To demonstrate that video-rate spectral domain optical coherence tomography (SDOCT) can qualitatively and quantitatively evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) glaucomatous structural changes. To correlate quantitative SDOCT parameters with disc photography and visual fields. Methods: SDOCT images from 4 glaucoma eyes (4 patients) with varying stages of open-angle glaucoma (ie, early, moderate, late) were qualitatively contrasted with 2 age-matched normal eyes (2 patients). Of 61 other consecutive patients recruited in an institutional setting, 53 eyes (33 patients) met inclusion/exclusion criteria for quantitative studies. Images were obtained using two experimental SDOCT systems, one utilizing a superluminescent diode and the other a titanium:sapphire laser source, with axial resolutions of about 6 ?m and 3 ?m, respectively. Results: Classic glaucomatous ONH and RNFL structural changes were seen in SDOCT images. An SDOCT reference plane 139 ?m above the retinal pigment epithelium yielded cup-disc ratios that best correlated with masked physician disc photography cup-disc ratio assessments. The minimum distance band, a novel SDOCT neuroretinal rim parameter, showed good correlation with physician cup-disc ratio assessments, visual field mean deviation, and pattern standard deviation (P values range, .0003–.024). RNFL and retinal thickness maps correlated well with disc photography and visual field testing. Conclusions: To our knowledge, this thesis presents the first comprehensive qualitative and quantitative evaluation of SDOCT images of the ONH and RNFL in glaucoma. This pilot study provides basis for developing more automated quantitative SDOCT-specific glaucoma algorithms needed for future prospective multicenter national trials.

Chen, Teresa C.

2009-01-01

250

Imaging Technology for Glaucoma  

Microsoft Academic Search

The introduction of several new imaging technologies for assessing the retinal nerve fibre layer (RNFL) and optic disc in the past decade is rapidly changing our current management of glaucoma. As a substantial number of retinal ganglion cells (RGCs) can be lost before visual field defects become manifest on standard white- on-white perimetry, there is great interest in these technologies

Jovina See; Balwantray Chauhan

251

Effects of Extrusion on Fibre Length in Sisal Fibre-Reinforced Polypropylene Composites  

NASA Astrophysics Data System (ADS)

Natural fibre reinforced thermoplastic composites find a wide array of applications in the automobile, building and construction industries. These composites are mostly produced by injection moulding or extrusion through properly designed dies. During these production processes, the shear forces exerted by the screw or ram leads to the degradation of the natural fibres. A screwless extruder that minimises fibre degradation and employs a reliable and low technology process has already been developed. However, the fibre degradation caused by the screwless extruder has not been compared with that of the conventional extruders. So, this study is focused on the influence of extrusion processes on the degradation of natural fibres in thermoplastic composites. Sisal fibres of 10 mm length were extruded with polypropylene, to furnish extrudates with a fibre mass fraction of 25%, using conventional single screw and screwless extruders. Polypropylene in the extrudates was dissolved in Xylene in a Sohxlet process; the fibres that were extracted were analysed for length variations. While fibre degradation in the form of fibre length variation is similar in both cases, this can be minimised in screwless extrusion by extending the gap between the front face of the cone and the orifice plate.

Pathi, Sridhar; Jayaraman, Krishnan

252

Automated segmentation by pixel classification of retinal layers in ophthalmic OCT images.  

PubMed

Current OCT devices provide three-dimensional (3D) in-vivo images of the human retina. The resulting very large data sets are difficult to manually assess. Automated segmentation is required to automatically process the data and produce images that are clinically useful and easy to interpret. In this paper, we present a method to segment the retinal layers in these images. Instead of using complex heuristics to define each layer, simple features are defined and machine learning classifiers are trained based on manually labeled examples. When applied to new data, these classifiers produce labels for every pixel. After regularization of the 3D labeled volume to produce a surface, this results in consistent, three-dimensionally segmented layers that match known retinal morphology. Six labels were defined, corresponding to the following layers: Vitreous, retinal nerve fiber layer (RNFL), ganglion cell layer & inner plexiform layer, inner nuclear layer & outer plexiform layer, photoreceptors & retinal pigment epithelium and choroid. For both normal and glaucomatous eyes that were imaged with a Spectralis (Heidelberg Engineering) OCT system, the five resulting interfaces were compared between automatic and manual segmentation. RMS errors for the top and bottom of the retina were between 4 and 6 ?m, while the errors for intra-retinal interfaces were between 6 and 15 ?m. The resulting total retinal thickness maps corresponded with known retinal morphology. RNFL thickness maps were compared to GDx (Carl Zeiss Meditec) thickness maps. Both maps were mostly consistent but local defects were better visualized in OCT-derived thickness maps. PMID:21698034

Vermeer, K A; van der Schoot, J; Lemij, H G; de Boer, J F

2011-05-27

253

Bacterial attachment on optical fibre surfaces.  

PubMed

Optical fibres have received considerable attention as high-density sensor arrays suitable for both in vitro and in vivo measurements of biomolecules and biological processes in living organisms and/or nano-environments. The fibre surface was chemically modified by exposure to a selective etchant that preferentially erodes the fibre cores relative to the surrounding cladding material, thus producing a regular pattern of cylindrical wells of approximately 2.5 mum in diameter and 2.5 mum deep. The surface hydrophobicity of the etched and non-etched optical fibres was analysed using the sessile pico-drop method. The surface topography was characterised by atomic force microscopy (AFM), while the surface chemistry was probed by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Six taxonomically different bacterial strains showed a consistent preference for attachment to the nano-scale smoother (R(q) = 273 nm), non-etched fibre surfaces (water contact angle, theta = 106 degrees +/- 4 degrees). In comparison, the surfaces of the etched optical fibres (water contact angle, theta = 96 degrees +/- 10 degrees) were not found to be amenable to bacterial attachment. Bacterial attachment on the non-etched optical fibre substrata varied among different strains. PMID:20358429

Mitik-Dineva, N; Wang, J; Truong, V K; Stoddart, P R; Alexander, M R; Albutt, D J; Fluke, C; Crawford, R J; Ivanova, E P

2010-05-01

254

Commercial optical fibre as TLD material.  

PubMed

This work presents a study of commercial SiO2 optical fibre thermoluminescence (TL) properties as part of the efforts within the Dosimetric Application Project at the Physics Institute of the University of Mexico to develop new radiation detection materials and technologies. The SiO2 commercial optical fibre studied demonstrates useful TL properties and is an excellent candidate for use in TL dosimetry of ionising radiation. The optical fibre's glow curve was observed between 30 and 400 degrees C after exposure to 60Co gamma radiation. One very well-defined glow peak has a maximum at 230 degrees C. The TL response between 100 and 350 degrees C increases monotonically over a wide dose range, from 0.1 Gy to several kGy. It is linear in the range 0.1-3 Gy, which is important for clinical high dose or accident dosimetry. The optical fibre demonstrated high data reproducibility, low residual signal and almost no fading in our study. Moreover, the optical fibre can be re-used several times, after thermal annealing, without any detriment in the dose-response. All these TL characteristics, plus the small size of the 150 microm diameter SiO2 optical fibre, the high flexibility, easy handling and low cost compared with other TL materials, make the commercial optical fibre a very promising TL material for use in research, medicine, industry, reactors, and a variety of other applications. PMID:16709711

Espinosa, G; Golzarri, J I; Bogard, J; García-Macedo, J

2006-05-18

255

Remotely tuneable optical filter based on polymer fibre Bragg grating  

NASA Astrophysics Data System (ADS)

We propose a remotely tuneable optical Bragg grating filter written in polymer optical fibre (POF). Fibre optical pumping in the fibre's absorption bands increases the fibre temperature, which causes a negative wavelength change of the POF Bragg grating. By choosing a proper pumping wavelength remote tuning of the optical filter can be readily realized without changing the gain of the optical signal.

Zhang, W.; Webb, D. J.; Peng, G.-D.

2011-05-01

256

Development of a high sensitivity DFB fibre laser hydrophone  

Microsoft Academic Search

Over the last three decades, extensive research has been carried out towards the development of fibre optic hydrophones. The initial designs focused on strain sensitivity enhancements through coatings and coiling long fibres on compliant mandrels. With the advent of fibre Bragg gratings and fibre lasers with ultra high sensitivity to strain, the interest has shifted towards employing these technologies in

Unnikrishnan Kuttan Chandrika; Venugopalan Pallayil; Chen Zhihao; Ng Jun Hong

2011-01-01

257

The use of unretted hemp fibre in composite manufacture  

Microsoft Academic Search

The usefulness of unretted hemp as a source of fibre for composite manufacture is investigated. A decortication machine was used to remove fibre from retted and unretted stems using two different decortication procedures, defined as ‘normal’ and ‘pinning’. The later caused less fibre breakage. Composites manufactured with fibre from the different treatments, and epoxy resin, were subjected to tensile tests

D. G Hepworth; R. N Hobson; D. M Bruce; J. W Farrent

2000-01-01

258

Use of Jute Fibre in Stone Matrix Asphalt  

Microsoft Academic Search

Synthetic fibres are conventionally used in the construction of Stone Matrix Asphalt (SMA) in bituminous pavements. The synthetic fibres are not manufactured in India and are imported at a higher cost. As an alternative to synthetic fibre, coated jute fibres were used and its properties were studied. The paper presents details of the laboratory investigations carried out to determine the

Pawan Kumar; P. K. Sikdar; Sunil Bose; Satish Chandra

2004-01-01

259

Alkali treatment of coir fibres for coir-polyester composites  

Microsoft Academic Search

Coir fibres were subjected to alkali treatment with a view to improving the wettability of coir fibres by a commercially available resin such as polyester. Tensile strength of the fibres increases by 15% when the fibres are soaked in 5% aqueous solution of NaOH at 28±1° C for 72 to 76 h after which it shows a gradual decrease. This

S. V. Prasad; C. Pavithran; P. K. Rohatgi

1983-01-01

260

Mechanical properties of continuous natural fibre-reinforced polymer composites  

Microsoft Academic Search

The mechanical behaviour high density polyethylene (HDPE) reinforced with continuous henequen fibres (Agave fourcroydes) was studied. Fibre-matrix adhesion was promoted by fibre surface modifications using an alkaline treatment and a matrix preimpregnation together with a silane coupling agent. The use of the silane coupling agent to promote a chemical interaction, improved the degree of fibre-matrix adhesion. However, it was found

P. J Herrera-Franco; A Valadez-González

2004-01-01

261

Predicting the tensile strength of natural fibre reinforced thermoplastics  

Microsoft Academic Search

The tensile strength of short natural fibre reinforced thermoplastics (NFRT) was modeled using a modified rule of mixtures (ROM) strength equation. A clustering parameter, requiring the maximum composite fibre volume fraction, forms the basis of the modification. The clustering parameter highlights that as fibre loading increases, the available fibre stress transfer area is decreased. Consequently, at high volume fractions this

Angelo G. Facca; Mark T. Kortschot; Ning Yan

2007-01-01

262

Mechanical properties of natural fibre-reinforced composites  

Microsoft Academic Search

Natural fibres were initially used in composite materials to predominately improve bulk and reduce cost rather than improving mechanical properties. But the environmental problems associated with the production and use of synthetic fibres have changed the scenario. In the previous decade, natural fibres have been extensively used as reinforcement materials for both synthetic and bio-degradable matrices. Natural fibre reinforcements have

Manik Bhowmick; Samrat Mukhopadhyay; Ramasamy Alagirusamy

2012-01-01

263

Deterministic and Probabilistic Tractography Based on Complex Fibre Orientation Distributions  

Microsoft Academic Search

We propose an integral concept for tractography to describe crossing and splitting fibre bundles based on the fibre orientation distribution function (ODF) estimated from high angular resolution diffusion imaging (HARDI). We show that in order to perform accurate probabilistic tractography, one needs to use a fibre ODF estimation and not the diffusion ODF. We use a new fibre ODF estimation

Maxime Descoteaux; Rachid Deriche; Thomas R. Knösche; Alfred Anwander

2009-01-01

264

Flax fibre quality and influence on interfacial properties of composites  

Microsoft Academic Search

Flax fibre holds the potential to serve as an alternative to glass fibre as reinforcement in composite applications. To fully achieve this, the interaction between fibre and matrix must be improved and more consistently controlled. Only then will industry accept natural fibres as a sustainable engineering material choice. Traditionally, interfacial strength improvement has been accomplished through expensive and time consuming

Jonn A. Foulk; Michael A. Fuqua; Chad A. Ulven; Mercedes M. Alcock

2010-01-01

265

Development and characterization of ceramic fibre-polyester laminates  

Microsoft Academic Search

Ceramic fibre waste generated during the production of ceramic fibres has been utilized for the development of laminates. The effect of resin to fibre ratio, concentration of catalyst and comonomer and process parameters have been studied. Various physico-mechanical properties of the laminates have been determined and comparative evaluation with commercially available fibre glass decorative laminates and gypsum board has been

M. Q. Parwez; Khursheed Fatma; S. K. Maiti; R. K. Khandal

2002-01-01

266

Dietary fibre content of dry and processed beans  

Microsoft Academic Search

Common beans (Phaseolus vulgaris L.) are a good source of protein, vitamins, minerals and especially dietary fibre. As beans are never eaten raw, the effects of soaking, cooking, soaking–cooking and canning on soluble, insoluble and total dietary fibre contents of beans are studied. Total dietary fibre content was determined by enzyme-gravimetric method. The fraction of insoluble dietary fibre was corrected

Tatjana Kutoš; Terezija Golob; Milica Ka?; Anamarija Plestenjak

2003-01-01

267

High-temperature behaviour of HPC with polypropylene fibres  

Microsoft Academic Search

The addition of polypropylene (PP) fibres to high-performance concrete (HPC) is one way to avoid spalling of concrete under fire conditions. The present work contributes both to the understanding of the way in which fibres act and to optimising the fibre dosage. Pore pressure measurements performed on heated specimens showed that the presence of fibres led to a large decrease

Pierre Kalifa; Grégoire Chéné; Christophe Gallé

2001-01-01

268

Separation of zirconium and hafnium using hollow fibres  

Microsoft Academic Search

A novel extraction chromatography system using hollow fibre membranes as supports is reported for separation of zirconium and hafnium. The effects of flow rate and flow mode, stationary phase concentration loaded on the hollow fibre membranes and fibre length on the separation were investigated. The separation performance of hollow fibre membrane chromatography can be analysed from existing theories of conventional

X. J Yang; A. G Fane; C Pin

2002-01-01

269

Investigation of mechanical dissipation in CO2 laser-drawn fused silica fibres and welds  

NASA Astrophysics Data System (ADS)

The planned upgrades to the LIGO gravitational wave detectors include monolithic mirror suspensions to reduce thermal noise. The mirrors will be suspended using CO2 laser-drawn fused silica fibres. We present here measurements of mechanical dissipation in synthetic fused silica fibres drawn using a CO2 laser. The level of dissipation in the surface layer is investigated and is found to be at a similar level to fibres produced using a gas flame. Also presented is a method for examining dissipation at welded interfaces, showing clear evidence of the existence of this loss mechanism which forms an additional component of the total detector thermal noise. Modelling of a typical detector suspension configuration shows that the thermal noise contribution from this loss source will be negligible.

Heptonstall, Alastair; Barton, Mark; Cantley, Caroline; Cumming, Alan; Cagnoli, Geppo; Hough, James; Jones, Russell; Kumar, Rahul; Martin, Iain; Rowan, Sheila; Torrie, Calum; Zech, Steven

2010-02-01

270

Toward the implementation of flexible sensing sheet with fibre Bragg grating sensing elements  

NASA Astrophysics Data System (ADS)

Optical sensing sheets, based on Fibre Bragg Grating (FBG) sensing elements embedded in exible polydimethyl- siloxane (PDMS), are produced and tested. The device shows promise in pressure mapping and tactile applications, in fields such as robotics and rehabilitation. FBGs inscribed in highly-birefringent photonic crystal fibres, reflecting two Bragg peaks, are used, and the potential to discriminate pressure and temperature is explored. The prototypes were produced by moulding technology and PDMS was cured at room temperature. One sample with FBGs embedded in the middle layer of a 2 mm thick PDMS sheet exhibited a linear pressure sensitivity of about 2:6 pm/kPa over the range of 0 - 250 kPa. Another sample was proposed and tested for temperature insensitive measurements, by realising local stress concentration at FBG sections of the embedded fibre.

Yan, Chunxiao; Ferraris, Eleonora; Reynaerts, Dominiek

2012-05-01

271

Fibre-optic-based fluoroimmunosensors  

SciTech Connect

Remote sensing of chemicals can be performed using fibre optic chemical sensors that use immunochemical reagent phases. Exploiting the specificity of antibody-antigen interactions and the sensitivity of laser-excited fluorimetry, highly selective measurements of ultra-trace levels of chemicals can be performed remotely and in situ via fluoroimmunoassay techniques. In this work, heterogeneous assay protocols using immunobeads are implemented. A passive sensor that samples analyte by diffusion through a permeable membrane and is capable of a single analysis is described and used for the measurement of a naturally fluorescent compound. Subsequently, a regenerable sensor that can perform assay procedures in a repetitive fashion is described and characterized. The versatility of this sensor for performing remote measurements using a variety of established fluorimmunoassay methodologies is discussed.

Sepaniak, M.J. (Univ. of Tennessee, Knoxville (United States)); Vodinh, T. (Oak Ridge National Lab., TN (United States))

1990-01-01

272

Optical fibre biosensors using enzymatic transducers to monitor glucose  

NASA Astrophysics Data System (ADS)

The construction and performance of a novel enzyme based optical sensor for in situ continuous monitoring of glucose in biotechnological production processes is presented. Sensitive optical coatings are formed from inorganic-organic hybrid polymers (ORMOCER®sORMOCER®: Trademark of Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. in Germany.) combined with a flurophore (ruthenium complex) and an enzyme, and applied to lenses, declad polymer optical fibre (POF) and polymer clad silica fibre (PCS). The enzyme, glucose oxidase, catalyzes oxidization of glucose to gluconic acid by depleting oxygen. Oxygen consumption is determined by measuring the fluorescence lifetime of metal organic ruthenium complexes which are quenched by oxygen. The coatings developed were designed to adhere to glass and polymer surfaces, to be compatible with enzymes and ruthenium complexes, and were demonstrated both as double- and single-layer structures. The sensor response to gaseous oxygen, dissolved oxygen and dissolved glucose was measured via fluorescence lifetime changes. A best detection limit of 0.5% (vol) has been determined for gaseous O2 with selected ORMOCER® sensing layers. Glucose concentrations were measured to a detection limit of 0.1 mmol L-1 over a range up to 30 mmol L-1. The sensor was usable for 30 days in a bioreactor. The opto-electronic instrumentation and performance in laboratory bioreactors and in an industrial reactor are evaluated.

Scully, P. J.; Betancor, L.; Bolyo, J.; Dzyadevych, S.; Guisan, J. M.; Fernández-Lafuente, R.; Jaffrezic-Renault, N.; Kuncová, G.; Matejec, V.; O'Kennedy, B.; Podrazky, O.; Rose, K.; Sasek, L.; Young, J. S.

2007-10-01

273

Dopant diffusion during optical fibre drawing.  

PubMed

Diffusion of Ge and F was studied during drawing of silica optical fibres. Preforms were drawn using various draw conditions and fibres analysed using the etching and Atomic Force Microscope (AFM) technique. The results were confirmed by comparison with fibre Refractive Index Profiles (RIP). Both Ge and F were found to diffuse at high temperature, 2100 degrees C, and low draw speed, 10m/min. Diffusion simulations showed that most diffusion occurred in the neck-down region. The draw temperature and preform feed rate had a comparable effect on diffusion, whereas preform diameter did not significantly affect the diffusion. PMID:19474911

Lyytikainen, K; Huntington, S; Carter, A; McNamara, P; Fleming, S; Abramczyk, J; Kaplin, I; Schötz, G

2004-03-22

274

Efficient Fibre Amplifiers Based on a Highly Er3+/Yb3+ Codoped Phosphate Glass-Fibre  

NASA Astrophysics Data System (ADS)

Highly Er3+/Yb3+-codoped single-mode phosphate glass fibre is fabricated by the rod-in-tube technique. The performances of high-concentration Er3+/Yb3+-codoped phosphate glass fibre amplifiers are investigated and discussed. An efficient optical fibre amplifier with a gain of 12.6 dB based on a 3.0 cm long Er3+/Yb3+-codoped phosphate glass fibre is demonstrated under a dual-pump configuration with two 976 nm fibre-pigtail laser diodes, which make it attractive for compact Er3+ -doped fibre amplifiers. The obtained noise figures of signal wavelength from 1525 to 1565 nm are less than 6.0 dB. Gain saturation behaviour at 1535 nm is also investigated, and the obtained saturation output power is larger than 10 dBm.

Xu, Shan-Hui; Yang, Zhong-Min; Feng, Zhou-Ming; Zhang, Qin-Yuan; Jiang, Zhong-Hong; Xu, Wen-Cheng

2009-04-01

275

Effect of the addition of different fibres on wheat dough performance and bread quality  

Microsoft Academic Search

A good correlation has become evident between fibre consumption and the reduction of coronary heart-related diseases and diabetes incidence. However, fibre intake is commonly lower than recommended. In consequence, the development of foods with high fibre content should be desirable. The potential use of various commercial fibres (carob fibre, inulin and pea fibre), as fibre-enriching agents in breadmaking, is reported.

Jinshui Wang; Cristina M Rosell; Carmen Benedito de Barber

2002-01-01

276

Study on manufacture of electric insulating paper and press board from non-wood fibres pulp  

Microsoft Academic Search

Cotton fibres, kenaf bast fibres, and leaf fibres have been evaluated as replacements for wood fibres in the manufacture of electric insulating paper and press board. Emphasis is placed on the use of O-A non-wood fibres to produce electric insulating paper. The results obtained indicate that kenaf bast fibre and cotton fibre can completely or partly replace NUKP pulp in

Chen Kuan; Liu De-Kuan; Wang Xin; Xia Tong-Jia

1991-01-01

277

Monitoring deformation and degradation of fibre reinforced thermoplastic composite material using imbedded Draw Tower fibre Bragg grating sensors and technology  

Microsoft Academic Search

Within this research draw tower fibre Bragg grating sensors will be used for imbedding in fibre reinforced thermoplastic composites. These sensors are based on a new fibre optic technology which allows developing high strength fibre Bragg gratings with a smaller diameter and special coatings. The improvement of these parameters is necessary for the accurate monitoring of the real strains inside

Eli Voet; Joris Degrieck; Hartmut Bartelt

278

Evaluation of the Influence of Fibre Length and Concentration on Mechanical Performance of Hemp Fibre Reinforced Polypropylene Composite  

Microsoft Academic Search

The paper deals widi die evaluation of interfacial shear stress (ISS) between reinforcement fibre (hemp) and polypropylene matrix through single fibre pull-out method and subsequently the critical length of the composite grade hemp fibre has been determined. In the present study the average ISS value of 5.9 MPa was used to determine the critical length of hemp fibre, which was

Muhammad Pervaiz; Mohini Sain; Arun Ghosh

2006-01-01

279

Influence of the Physical Structure of Flax Fibres on the Mechanical Properties of Flax Fibre Reinforced Polypropylene Composites  

Microsoft Academic Search

This study investigates the influence of the physical structure of flax fibres on the mechanical properties of polypropylene (PP) composites. Due to their composite-like structure, flax fibres have relatively weak lateral bonds which are in particular present in flax fibres that are often used in natural fibre mat reinforced thermoplastics (NMT). These weak bonds can be partly removed by combing

M. J. A. van den Oever; H. L. Bos; M. J. J. M. van Kemenade

2000-01-01

280

Integration and assessment of fibre Bragg grating sensors in an all-fibre reinforced polymer composite road bridge  

Microsoft Academic Search

This paper reports on the integration and assessment of 40 ruggedly protected fibre Bragg grating sensors (FBGs) in an all-glass fibre reinforced polymer composite road bridge. This bridge is reported to be Europe's first all-fibre reinforced composite bridge. A unique feature of this bridge was that it was constructed from pultruded glass fibre composite sections, which were bonded on site.

Y. M. Gebremichael; W. Li; W. J. O. Boyle; B. T. Meggitt; K. T. V. Grattan; B. McKinley; G. F. Fernando; G. Kister; D. Winter; L. Canning; S. Luke

2005-01-01

281

Fibre Bragg grating interrogation technique based on a chirped grating written in an erbium-doped fibre  

Microsoft Academic Search

A fibre Bragg grating interrogation technique with tunable sensitivity is reported. It relies on the utilization of the edge filtering concept applied to a chirped fibre Bragg grating (CFBG) written in an erbium-doped fibre as the processing element. Through the combination of the optical gain properties of the erbium-doped fibre and of the distributed wavelength reflection characteristics of the CFBG,

R. Romero; O. Frazão; P. V. S. Marques; H. M. Salgado; J. L. Santos

2003-01-01

282

Effect of fibre—matrix interphase on wave propagation along, and scattering from, multilayered fibres in composites. Transfer matrix approach  

Microsoft Academic Search

This paper reports an analysis of the effect of the fibre-matrix interphase on ultrasonic wave interaction with multilayered fibres in a solid matrix. A transfer method is developed, which significantly simplifies the theoretical treatment of wave interaction with multilayered fibres. Two phenomena are investigated, one the dispersion of waves propagating in the composite along fibres, the other the scattering of

W Huang; S. I Rokhlin; Y. J Wang

1995-01-01

283

Determination of the fibre volume content in natural fibre-reinforced composites by ultimate analysis  

Microsoft Academic Search

Natural fibre-reinforced plastics (NFRP) with renewable polymers as matrices are expected to be an increasing market in the\\u000a future. In this context the quantification of natural fibre volume content in composites is an important parameter for manufacturers\\u000a to check the laminate quality. This paper reports a new time and cost efficient method for the determination of natural fibre\\u000a volume content

T. Mahrholz; U. Riedel

2009-01-01

284

Gibberellin mediates the development of gelatinous fibres in the tension wood of inclined Acacia mangium seedlings.  

PubMed

Background and Aims Gibberellin stimulates negative gravitropism and the formation of tension wood in tilted Acacia mangium seedlings, while inhibitors of gibberellin synthesis strongly inhibit the return to vertical growth and suppress the formation of tension wood. To characterize the role of gibberellin in tension wood formation and gravitropism, this study investigated the role of gibberellin in the development of gelatinous fibres and in the changes in anatomical characteristics of woody elements in Acacia mangium seedlings exposed to a gravitational stimulus. Methods Gibberellin, paclobutrazol and uniconazole-P were applied to the soil in which seedlings were growing, using distilled water as the control. Three days after the start of treatment, seedlings were inclined at 45 ° to the vertical and samples were harvested 2 months later. The effects of the treatments on wood fibres, vessel elements and ray parenchyma cells were analysed in tension wood in the upper part of inclined stems and in the opposite wood on the lower side of inclined stems. Key Results Application of paclobutrazol or uniconazole-P inhibited the increase in the thickness of gelatinous layers and prevented the elongation of gelatinous fibres in the tension wood of inclined stems. By contrast, gibberellin stimulated the elongation of these fibres. Application of gibberellin and inhibitors of gibberellin biosynthesis had only minor effects on the anatomical characteristics of vessel and ray parenchyma cells. Conclusions The results suggest that gibberellin is important for the development of gelatinous fibres in the tension wood of A. mangium seedlings and therefore in gravitropism. PMID:24043495

Nugroho, Widyanto Dwi; Nakaba, Satoshi; Yamagishi, Yusuke; Begum, Shahanara; Marsoem, Sri Nugroho; Ko, Jae-Heung; Jin, Hyun-O; Funada, Ryo

2013-09-15

285

Mathematical model of the spinning of microstructured fibres.  

PubMed

We construct a fluid mechanics model of the drawing of microstructured optical fibres ('holey fibres'). This model can be used to understand and quantify methods for controlling the fibre geometry. The effects of preform rotation are included to examine methods for reducing fibre birefringence. Asymptotic numerical-solutions are obtained and applied to two typical microstructured-fibres and a number of practical suggestions are made for achieving sub-mm spin pitches without damaging the microstructure within. PMID:19488219

Voyce, Christopher; Fitt, Alistair; Monro, Tanya

2004-11-15

286

Manufacture and characterization of high activity piezoelectric fibres  

NASA Astrophysics Data System (ADS)

Piezoelectric fibres are finding increasing application in a variety of piezoelectric composites, including active fibre composites (AFCs). This paper describes the manufacture and characterization of lead zirconate titanate (PZT) fibres manufactured by viscous plastic processing (VPP). The manufacturing method will be described along with a systematic characterization of the macrostructure, microstructure, phase composition and low and high field piezoelectric properties. A comparison with other available PZT fibres will be made, which demonstrates that the VPP PZT fibres display high piezoelectric coefficients.

Bowen, C. R.; Stevens, R.; Nelson, L. J.; Dent, A. C.; Dolman, G.; Su, B.; Button, T. W.; Cain, M. G.; Stewart, M.

2006-04-01

287

An all-fibre robust and tunable Raman fibre laser with reconfigurable asymmetric cavities  

NASA Astrophysics Data System (ADS)

A robust Raman fibre laser (RFL) for tunable and multiple outputs has been proposed using an all-fibre asymmetric cavity which is composed of a wideband chirped fibre Bragg grating (CFBG) and narrowband tunable fibre Bragg gratings (TFBGs). The wideband CFBG has high reflectivity across the spectral range from 1404 to 1465 nm as an input reflector. Output couplers (OCs) consist of three TFBGs with center wavelengths of 1410, 1425 and 1440 nm, respectively, which can each be tuned over 10 nm. The output power and wavelength can be flexibly controlled by tuning of TFBGs in the 14xx nm band.

Im, Young-Eun; Hann, Swook; Kim, Hangeul; Kim, Dong-Hwan; Park, Chang-Soo

2009-03-01

288

Field examples for optical fibre sensor condition diagnostics based on distributed fibre optic strain sensing  

NASA Astrophysics Data System (ADS)

Fibre optic sensors for monitoring in safety-relevant structures have to be validated in order to proof their reliability under typical structural load conditions. The reliable use of optical fibre sensors depends strongly on an appropriate and qualitative application. Diagnostics of the physical condition of embedded and surface-applied fibre optic strain sensors are demonstrated on field examples. Distributed strain measurement based on Rayleigh backscattering is used to determine breakage of the fibre, interface adhesion problems and to identify application related strain transfer mechanisms.

Kusche, Nadine; Schukar, Vivien; Hofmann, Detlef; Basedau, Frank; Habel, Wolfgang; Woschitz, Helmut; Lienhart, Werner

2013-05-01

289

In vivo imaging of retinal ganglion cell axons within the nerve fiber layer.  

PubMed

Purpose. Optic nerve injury causes loss of retinal ganglion cells (RGCs) and their axons. The reduction in RGC counts over time in axonal injury is well studied, but the correlation with the timing of anterograde and retrograde axonal degeneration is less clear. The authors longitudinally imaged RGC axons stained with a chloromethyl derivative of fluorescein diacetate (CMFDA) in live rats after optic nerve injury. Methods. Optic nerves were transected. Three days later CMFDA was intravitreously injected. Confocal scanning laser ophthalmoscopy was performed daily, and mean fluorescence intensity and the number of CMFDA bundles were calculated. RGC soma survival was studied after retrograde fluorescence labeling. Retinal nerve fiber layer (RNFL) thickness was evaluated histologically. Results. CMFDA-positive RGC axon bundles could be imaged in vivo. Axons lost 68% +/- 29% of their fluorescence by 7 days after transection compared with 25% +/- 21% in nontransected eyes. The number of labeled axon bundles decreased by 61% +/- 28% at 7 days after transection compared with 26% +/- 9% in nontransected eyes. The number of retrograde-labeled RGCs detected in vivo declined by 53% at 7 days and by 76% at 14 days after transection. RGC soma and CMFDA axon counts decreased most rapidly between 5 and 7 days after transection. Histologic examination demonstrated a reduction in RNFL thickness 7 days after transection. Conclusions. Intravitreal CMFDA can be used to longitudinally monitor RGC axons within the RNFL in vivo. Imaging the disappearance of retrograde-labeled RGC somas and axons indicates that axonal and somal degeneration occur in parallel after axotomy. PMID:19797216

Kanamori, Akiyasu; Catrinescu, Maria-Magdalena; Traistaru, Manuela; Beaubien, Rachel; Levin, Leonard A

2009-09-24

290

Cogeneration Alternatives for Keyes Fibre Company.  

National Technical Information Service (NTIS)

Cogeneration alternatives for Keyes Fibre Company paper mill are assessed. Four coal-fired cogeneration systems and one thermal-energy-only plant are conceptually designed and evaluated with respect to the existing oil-fired, noncogenerating system. Cogen...

C. Lee A. Davis

1980-01-01

291

Automated 3D segmentation of intraretinal layers from optic nerve head optical coherence tomography images  

NASA Astrophysics Data System (ADS)

Optical coherence tomography (OCT), being a noninvasive imaging modality, has begun to find vast use in the diagnosis and management of ocular diseases such as glaucoma, where the retinal nerve fiber layer (RNFL) has been known to thin. Furthermore, the recent availability of the considerably larger volumetric data with spectral-domain OCT has increased the need for new processing techniques. In this paper, we present an automated 3-D graph-theoretic approach for the segmentation of 7 surfaces (6 layers) of the retina from 3-D spectral-domain OCT images centered on the optic nerve head (ONH). The multiple surfaces are detected simultaneously through the computation of a minimum-cost closed set in a vertex-weighted graph constructed using edge/regional information, and subject to a priori determined varying surface interaction and smoothness constraints. The method also addresses the challenges posed by presence of the large blood vessels and the optic disc. The algorithm was compared to the average manual tracings of two observers on a total of 15 volumetric scans, and the border positioning error was found to be 7.25 +/- 1.08 ?m and 8.94 +/- 3.76 ?m for the normal and glaucomatous eyes, respectively. The RNFL thickness was also computed for 26 normal and 70 glaucomatous scans where the glaucomatous eyes showed a significant thinning (p < 0.01, mean thickness 73.7 +/- 32.7 ?m in normal eyes versus 60.4 +/- 25.2 ?m in glaucomatous eyes).

Antony, Bhavna J.; Abràmoff, Michael D.; Lee, Kyungmoo; Sonkova, Pavlina; Gupta, Priya; Kwon, Young; Niemeijer, Meindert; Hu, Zhihong; Garvin, Mona K.

2010-03-01

292

Oxidation protection for carbon fibre composites  

Microsoft Academic Search

Carbon fibre-reinforced ceramic matrix composites are promising candidate materials for high-temperature structural applications such as gas turbine blades. In oxidizing environments at temperatures above 400°C, however, carbon fibres are rapidly oxidized. There is, therefore, a need to coat the composite in order to protect it against oxidation. This review identifies the requirements of an effective oxidation protection system for carbon

M. E. Westwood; J. D. Webster; R. J. Day; F. H. Hayes; R. Taylor

1996-01-01

293

Optimising industrial hemp fibre for composites  

Microsoft Academic Search

The optimisation of New Zealand grown hemp fibre for inclusion in composites has been investigated. The optimum growing period was found to be 114 days, producing fibres with an average tensile strength of 857MPa and a Young’s modulus of 58GPa. An alkali treatment with 10wt% NaOH solution at a maximum processing temperature of 160°C with a hold time of 45min

K. L. Pickering; G. W. Beckermann; S. N. Alam; N. J. Foreman

2007-01-01

294

Nonlinear switching in fibre Bragg gratings.  

PubMed

We report on our recent experiments on nonlinear switching in fibre Bragg gratings. Using an all-fibre source we show an increase in transmission of a FBG from 4% to 40% at high powers. This switching is associated with the formation of gap solitons inside the grating. We also demonstrate an all-optical AND gate using polarization coupled gap solitons and the optical pushbroom. PMID:19384393

Broderick, N; Taverner, D; Richardson, D

1998-11-23

295

Synthesis of continuous silicon carbide fibre  

Microsoft Academic Search

The polycarbosilane (PC-470) synthesized by thermal decomposition of polydimethylsilane was melt-spun. The conversion process of the fibre into silicon carbide fibre was investigated by chemical analysis, TG-DTA and infra-red spectrum analysis, and measurements of the mechanical properties and densities. The conversion process of polycarbosilane (PC-TMS) synthesized by Fritz was examined and compared with the conversion process of PC-470. It is

Y. Hasegawa; M. Iimura; S. Yajima

1980-01-01

296

Structure of polyacrylonitrile fibres modified with polyethylenimine  

Microsoft Academic Search

After the treatment of carboxylated PAN with polyethylenimine the fibre center retains the absorption band at 1720 cm-i produced by the free-CO groups and contains new bands at 1410 and 1590 cm-1 (ionized COO-groups), a fact which shows that the sorption of PEI by carboxyl-contain ing PAN fibre proceeds in accordance with an ionic mechanism. Since sorbents of this type

N. A. Gorodetskaya; I. B. Ratushnyak; I. G. Rumynskaya; L. V. Emets

1980-01-01

297

Studies of the AZ91 magnesium alloy / SiO2-coated carbon fibres composite microstructure  

NASA Astrophysics Data System (ADS)

The microstructure of magnesium matrix composite reinforced with SiO2nano-layer coated carbon fibres, deposited by sol-gel method was characterized. The composite was obtained by infiltration method and the effect of SiO2 on the composite microstructure was analyzed by scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM+EDS) and transmission electron microscopy combined with energy-dispersive X-ray spectroscopy (TEM+EDS) methods. Good wettability of fibres by the magnesium alloy AZ91 (Al 9 wt%, Zn 0.3 wt%) was confirmed since fibres were closely surrounded with alloy and pulling-out effect was not visible. The interface region was evidently with aluminium enriched. Near carbon fibre surface a regular layer of SiOX oxide enriched with Al was detected by high angle annular dark field image (HAADF) combined with energy-dispersive X-ray spectroscopy (EDS). The plate or needle shaped very fine particles of Al12Mg17 were identified near the AZ91 matrix zone by bright field (BF) and selected area electron diffraction (SADP).

Olszówka-Myalska, A.; Botor-Probierz, A.

2010-02-01

298

Role of fibre–fibre and fibre–matrix adhesion in stress transfer in composites made from resin-impregnated paper sheets  

Microsoft Academic Search

Paper-reinforced plastics are gaining increased interest as packaging materials, where mechanical properties are of great importance. Strength and stress transfer in paper sheets are controlled by fibre–fibre bonds. In paper-reinforced plastics, where the sheet is impregnated with a polymer resin, other stress-transfer mechanisms may be more important. The influence of fibre–fibre bonds on the strength of paper-reinforced plastics was therefore

K. M. Almgren; E. K. Gamstedt; P. Nygård; F. Malmberg; J. Lindblad; M. Lindström

2009-01-01

299

Mechanical properties of short flax fibre bundle\\/polypropylene composites: Influence of matrix\\/fibre modification, fibre content, water uptake and recycling  

Microsoft Academic Search

The aim of this work was to compare the effect of modification way of short flax fibre bundle\\/polypropylene (PP) composites on mechanical properties. Modification was carried out on fibre surface and also modifying PP matrix using several amounts of maleic anhydride-polypropylene copolymer (MAPP) as compatibilizer. The optimum doses of two different MAPP compatibilizers have been obtained. The effect of fibre

A. Arbelaiz; B. Fernández; J. A. Ramos; A. Retegi; R. Llano-Ponte; I. Mondragon

2005-01-01

300

Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices.  

PubMed

Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg(2+) in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM). The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM) and X-ray diffraction (XRD) analysis, respectively. The roughness of the coatings was seen to increase from 40 ± 1?nm to 80 ± 1?nm. The mechanical properties (tensile strength and modulus) of fibre with coatings decreased with increased magnesium coating thickness. PMID:24066297

Liu, Xiaoling; Grant, David M; Parsons, Andrew J; Harper, Lee T; Rudd, Chris D; Ahmed, Ifty

2013-08-27

301

An alternative method to develop fibre grating temperature sensors using the fibre loop ringdown scheme  

Microsoft Academic Search

We present a new method to develop fibre Bragg grating (FBG)-based temperature sensors using the fibre grating loop ringdown (FGLRD) technique. With this novel approach, temperature is sensed by measuring the wavelength-dependent optical loss resulting from the temperature variations incurred in the FBG. The sensor incorporates a standard telecommunications diode laser and an inexpensive photodetector and achieves rapid temperature measurements

Chuji Wang; A. Mbi

2006-01-01

302

Optical Fibres With Depressed Claddings For Suppression of Coupling into Cladding Modes in Fibre Bragg Gratings  

Microsoft Academic Search

A new method for suppression of coupling from guided optical modes into cladding modes in an optical fibre Bragg grating using a fibre with a strongly depressed cladding is proposed. Strong suppression of the coupling has been demonstrated both theoretically and experimentally.

L. Dong; L. Reekie; J. L. Cruz; J. E. Caplen; J. P. de Sandro; D. N. Payne

1997-01-01

303

Fibre Bragg grating photowriting in microstructured optical fibres for refractive index measurement  

Microsoft Academic Search

We report results relating to fibre Bragg grating photowriting in two kinds of Ge-doped core microstructured optical fibre devoted to sensing applications. A cross-comparison between theoretical and experimental modal field patterns is carried out. We present the first values of the spectral sensitivity of a Bragg grating in relation to the refractive index of calibrated oils inserted into the holes.

M. C. Phan Huy; G. Laffont; Y. Frignac; V. Dewynter-Marty; P. Ferdinand; P. Roy; J.-M. Blondy; D. Pagnoux; W. Blanc; B. Dussardier

2006-01-01

304

Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices  

PubMed Central

Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM). The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM) and X-ray diffraction (XRD) analysis, respectively. The roughness of the coatings was seen to increase from 40 ± 1?nm to 80 ± 1?nm. The mechanical properties (tensile strength and modulus) of fibre with coatings decreased with increased magnesium coating thickness.

Liu, Xiaoling; Grant, David M.; Parsons, Andrew J.; Harper, Lee T.; Rudd, Chris D.; Ahmed, Ifty

2013-01-01

305

Composite second-order performance improvement in optical fibre CATV transmission system using chirped fibre grating  

Microsoft Academic Search

Theoretically, we analyse the dispersion compensation characteristics of the chirped fibre grating (CFG) in an optical fibre cable television (CATV) system and obtain the analytic expression of the composite second-order (CSO) distortion using the time-domain form of the field envelope wave equation. The obtained result is in good agreement with the numerical simulation result. Experimentally, we verify the result by

Qing Ye; Feng Liu; Hai-Wen Cai; Rong-Hui Qu; Zu-Jie Fang

2005-01-01

306

Wrapper Fibres in Open-End Rotor-Spun Yarns: Yarn Properties and Wrapper Fibres  

Microsoft Academic Search

Wrapper fibres (WFs) and their formation mechanisms, as well as their effects on the pro - perties of open-end rotor spun yarns, have been investigated. For this purpose, different yarn samples (100% PES) were produced under different operating conditions. The tight belts on the surface of the selected yarn samples were counted, and the mean number of wrapper fibres per

Erdem Koç; Carl Anthony Lawrence; Cherian Iype

2005-01-01

307

Fourier-Domain Optical Coherence Tomography and Adaptive Optics Reveal Nerve Fiber Layer Loss and Photoreceptor Changes in a Patient With Optic Nerve Drusen  

PubMed Central

Background New technology allows more precise definition of structural alterations of all retinal layers although it has not been used previously in cases of optic disc drusen. Methods Using Stratus and Fourier domain (FD) optical coherence tomography (OCT) and adaptive optics (AO) through a flood-illuminated fundus camera, we studied the retinas of a patient with long-standing optic disc drusen and acute visual loss at high altitude attributed to ischemic optic neuropathy. Results Stratus OCT and FD-OCT confirmed severe thinning of the retinal nerve fiber layer (RNFL). FD-OCT revealed disturbances in the photoreceptor layer heretofore not described in optic disc drusen patients. AO confirmed the FD-OCT findings in the photoreceptor layer and also showed reduced cone density at retinal locations associated with reduced visual sensitivity. Conclusions Based on this study, changes occur not only in the RNFL but also in the photoreceptor layer in optic nerve drusen complicated by ischemic optic neuropathy. This is the first reported application of FD-OCT and the AO to this condition. Such new imaging technology may in the future allow monitoring of disease progression more precisely and accurately.

Choi, Stacey S.; Zawadzki, Robert J.; Greiner, Mark A.; Werner, John S.; Keltner, John L.

2008-01-01

308

Conductive wood microfibres for smart paper through layer-by-layer nanocoating  

Microsoft Academic Search

A layer-by-layer (LbL) self-assembly of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) on lignocellulose wood microfibres was used to make conductive fibres and paper. Polycations such as poly(allylamine hydrochloride) (PAH), and poly(ethyleneimine) (PEI) were used in alternate deposition with anionic conductive polythiophene (PEDOT-PSS) to construct the multilayer nanofilms on wood microfibres. Current-voltage characterization was measured on single fibres using a Keithley probe measurement system after

Mangilal Agarwal; Yuri Lvov; Kody Varahramyan

2006-01-01

309

DESIGN NOTE: Surface microscopy and fibre characterization using a multimode-fibre reflectance microscope  

NASA Astrophysics Data System (ADS)

A remarkably simple scanning infrared surface-reflectance microscope based on a multimode-fibre-coupled diode laser together with straightforward electronics and scanning stage is described. The design does not require alignment and completely avoids the use of objectives, beamsplitters and other optics normally associated with such microscopes. The axial response, resolution and imaging properties for non-interferometric operation are characterized. A geometric model for the transmission of such a microscope using an idealized step/graded-index multimode fibre is presented. This model is used to explain the axial response of the microscope. Finally, a new method for determination of the numerical aperture and index-grading parameter of multimode fibres is proposed. This method is based on the geometric model together with axial-response measurements using the microscope in such a way that the fibre probe is the actual test fibre.

Lukins, P. B.; Rehman, S.; Stevens, G. B.

2000-04-01

310

The abrasive wear behaviour of continuous fibre polymer composites  

Microsoft Academic Search

The dry abrasive-dominant wear behaviour of several composite materials consisting of uni-directional continuous fibres and polymer matrices was investigated. Seven materials were examined: neat epoxy (3501-6), carbon fibre epoxy (AS4\\/3501-6), glass fibre\\/epoxy (E-glass\\/ 3501-6), aramid fibre\\/epoxy (K49\\/3501-6), neat polyetheretherketone (PEEK), carbon fibre\\/PEEK (APC2) and aramid fibre\\/PEEK (K49\\/PEEK). The wear behaviour of the materials was characterized by experimentally determining the friction

M. Cirino; R. B. Pipes; K. Friedrich

1987-01-01

311

Radiation-resistant erbium-doped silica fibre  

SciTech Connect

It is shown that the service life of erbium-doped fibres can be increased many times under conditions of an elevated radiation level by loading the fibre glass network with molecular hydrogen. Backdiffusion of hydrogen from the fibre in the process of its operation is virtually excluded for the fibre covered with a hermetic carbon coating. It is shown that this technique of fibre preparation allows one to slow down significantly degradation of the lasing properties of erbium fibres under the conditions characteristic of space applications. (special issue devoted to the 25th anniversary of the a.m. prokhorov general physics institute)

Zotov, K V; Likhachev, M E; Tomashuk, A L; Bubnov, M M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Yashkov, M V; Gur'yanov, A N [Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

2007-10-31

312

Flexible, fibre-addressable surface-plasmon-resonance chip  

NASA Astrophysics Data System (ADS)

Surface plasmon resonance (SPR) sensors exploit optical coupling to surface plasmons, light waves bound to a metal surface. In the most common configuration, a SPR sensor is used with an external light source, optical components to polarize incident light and guide light to and from a metal surface, a coupling device to convert free-space light into surface plasmons and back into free-space light, and a light detector. The light source, the optical components, and the light detector are external to the SPR device, and the coupling structure is often integrated directly with the surface-plasmon-sustaining metal surface. The requirement of several external components restricts the miniaturization of SPR devices and prohibits low-cost implementation. To address these limitations, we design, fabricate, and test a new SPR device chip that is fibre-addressable, does not require a discrete coupling structure, and integrates light delivery, light polarization control, surface plasmon coupling onto a thin, flexible substrate. Our SPR chip is constructed from a thin gold layer deposited on top of a clear plastic sheet, which is then optically connected from the bottom surface onto a plastic linear polarizer sheet. Two cleaved fibres, one to input light and the other to collect reflected light, are then optically attached to SPR device. We experimentally characterize the SPR device and find good agreement between our measurements and a theoretical model based on transfer matrix formalism.

Chowdhury, Faqrul; Chau, Kenneth J.

2012-02-01

313

Grating-free nth order cascaded Raman fibre lasers using highly Ge-doped low loss fibre.  

PubMed

Pumped by a narrow band Nd(3+)-doped fibre laser, a grating-free three-wavelength Raman fibre laser has been demonstrated. More than 1.3W output power at the third Stokes line of 1230 nm, a bandwidth of 1.8nm and a slope efficiency of ~28% was measured. A four-wavelength Raman fibre laser was also demonstrated using a different resonator that consisted of a 4% fibre end reflector, a dielectric mirror and a single fibre Bragg grating. This method is simple, versatile and cheap compared with conventional methods employing fibre Bragg gratings used to resonate all Stokes wavelengths. PMID:19483946

Zhao, Yucheng; Li, Yahua; Jackson, Stuart

2004-08-23

314

Ca²+ sorption on regenerated cellulose fibres.  

PubMed

High calcium content in cellulose materials can cause considerable problems in pulp processing, textile chemical treatment and consumer use, e.g. dyeing operations or household laundry. The Ca(2+) binding capacity of cellulose also is of relevance in food and medical applications. Through their carboxyl group content regenerated cellulose fibres can act as weak anion exchangers, thus all types of regenerated cellulose fibres such as lyocell, viscose and modal fibres, show a distinct ability to bind Ca(2+) ions. The binding capacity is limited by the carboxyl group content, which was determined with 15 mmol/kg for lyocell fibres and 20 mmol/kg for viscose fibres, using the Methylene Blue sorption method. The presence of bound Ca(2+) also was demonstrated by complex formation with alizarin. The molar ratio between carboxylic group content and bound Ca(2+) ions was one Ca(2+) ion for a single carboxyl group. As a result of Ca(2+) sorption a positive net charge of the cellulose results and another anion has to be bound as counter ion for reasons of charge neutralisation. Results of potentiometric titrations indicate HCO(3)(-) to be present as counter ion in the Ca(2+) cellulose system. Thus under the experimental conditions studied, bound Ca(2+) is proposed to be present in the form COO(-)Ca(2+)HCO(3)(-). PMID:22840023

Fitz-Binder, Christa; Bechtold, Thomas

2012-06-20

315

Structural behaviour of fibre metal laminates subjected to a low velocity impact  

Microsoft Academic Search

Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile\\u000a impact, which produced the corresponding load-displacement traces and deformation\\/failure modes for the validation of numerical\\u000a models. Finite element (FE) models were then developed to simulate the impact behaviour of FMLs tested. The aluminium (alloy\\u000a grade 2024-0) layer was modelled as an isotropic

Jiying Fan; Zhongwei Guan; W. J. Cantwell

2011-01-01

316

Failure of ceramic\\/fibre-reinforced plastic composites under hypervelocity impact loading  

Microsoft Academic Search

The hypervelocity impact limit, V50, of alumina\\/fibre-reinforced plastic (FRP) target materials was studied with different adhesive layer thicknesses and two kinds of FRP. A high-speed camera was used to analyse the perforation phenomena of target materials. In addition, the dishing and bulging extent of FRP as a rear material were investigated using a digital planimeter from a series of high-speed

J JANG; Y. YUN; H. KIM

1997-01-01

317

On a direct determination of non-uniform internal strain fields using fibre Bragg gratings  

Microsoft Academic Search

A new method for measuring non-uniform strain fields using fibre Bragg grating sensors is proposed and demonstrated. The method is based on the measurement of the complex impulse response of the grating by optical low coherence reflectometry and the retrieval of the local Bragg wavelength by the layer-peeling technique. This method is applied to measurements of non-uniform strain distributions generated

Philippe Giaccari; Gabriel R. Dunkel; Laurent Humbert; John Botsis; Hans G. Limberger; René P. Salathé

2005-01-01

318

Imparting electrical conductivity to a plastic optical fibre based on poly(methyl methacrylate)  

Microsoft Academic Search

In this study, as a preliminary work on the realisation of an optical\\/electrical acupuncture needle, we have attempted to impart electrical conductivity to a plastic optical fibre (POF) by coating a thin gold layer on its surface. First, we investigated the adhesion between the gold and two different substrates, poly(methyl methacrylate) (PMMA) and poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-co-HFP)), which were used as

Suk Min Kim; Sung Hun Kim; Soo Bong Jo; Eun Ju Park; Dong Lyun Cho; Moo Sung Lee

2010-01-01

319

Adhesive strength of bonds of polymers with carbon fibres at different loading rates  

Microsoft Academic Search

The effect of the loading rate on the strength of the interface of bonds of UKN-5000-P carbon fibres ?7 ?m in diameter with\\u000a thermosetting (EDT-10 epoxy binder) and thermoplastic (PSK-1 polyarylene sulfone) matrices was investigated. The adhesive\\u000a strength ?0 of the bonds was determined in shear of a monofilament relative to the polymer layer (pull-out method). It was found that

Yu. A. Gorbatkina; V. G. Ivanova-Mumzhieva; A. Ya. Gorenberg

1999-01-01

320

Eucalyptus pulp fibres as alternative reinforcement to engineered cement-based composites  

Microsoft Academic Search

This paper evaluates the advantages of using hardwood short fibre pulp (eucalyptus) as alternative to softwood long fibre pulp (pinus) and polymer fibres, traditionally used in reinforcement of cement-based materials. The effects of cellulose fibre length on microstructure and on mechanical performance of fibre–cement composites were evaluated before and after accelerated ageing cycles. Hardwood pulp fibres were better dispersed in

G. H. D. Tonoli; H. Savastano Jr.; E. Fuente; C. Negro; A. Blanco; F. A. Rocco Lahr

2010-01-01

321

A Physically Based Failure Hypothesis for Short-Fibre Reinforced Thermoplastics for Finite-Element-Analysis  

Microsoft Academic Search

A physically based failure hypothesis is developed for short fibre reinforced thermoplastics. The mode l is valid for three-dimensional, multiaxial stress stat es. We begin the approach by reviewing uniaxial tensile strength models, which take the fibre orientation and fibre length distribution into account and use the critical fibre length concept to distinguish betwee n fibre- pullout and fibre breakage

B. Mlekusch; B. Spiegl; A. Ableidinger

322

The Strengths of Cements Reinforced with Glass Fibres.  

National Technical Information Service (NTIS)

Fibrous composite materials utilizing ceramic fibres and inorganic cements offer a potential source of new lightweight, strong and durable materials. Commercial glass fibres now available are not durable in an alkaline medium of the kind present in most h...

F. J. Grimer M. A. Ali

1969-01-01

323

Uv-written in-fibre Bragg gratings  

Microsoft Academic Search

The techniques for fabrication and the properties of periodic and aperiodic fibre Bragg gratings produced by UV exposure in photosensitive optical fibres are reviwwed with an emphasis on applications.

I. Bennion; J. A. R. Williams; L. Zhang; K. Sugden; N. J. Doran

1996-01-01

324

Refractive index profile and geometry measurements in multicore fibres  

NASA Astrophysics Data System (ADS)

The refracted near-field technique (RNF) has been applied to the measurement of the refractive index profiles in multicore fibres (MCF). The fibre core diameter and the intercore distances have been determined.

Conde, R.; Depeursinge, C.; Gisin, B.; Gisin, N.; Groebli, B.

1996-05-01

325

Optical fibre tapers: focal reduction and magnification  

NASA Astrophysics Data System (ADS)

Optical fibre tapers show great promise as a simple and highly effective means of efficiently coupling broadband light into astronomical instruments. Fibre tapers can replace bulk optics systems such as focal plane reduction and magnification optics by controlling and manipulating image scale and beam angle in a small, robust and cost effective device. However, like any new photonic device fibre tapers must be thoroughly characterised before they can be applied to astronomy. The specific characteristics of importance are the device’s ability to maintain the etendue of the system and to transmit light over a broad wavelength range with minimal loss. In this paper we present the manufacturing technique and preliminary results for the first large taper transition prototype devices manufactured in-house intended for astronomy applications. Characteristics addressed include: beam angle, focal ratio degradation and throughput for devices with a conversion ratio of 5 (5 x focal reduction or magnification) for two taper transition lengths.

Haynes, Dionne M.; Haynes, Roger; Olaya, J. C.; Leon-Saval, Sergio G.

2012-09-01

326

On the topology of chromatin fibres  

PubMed Central

The ability of cells to pack, use and duplicate DNA remains one of the most fascinating questions in biology. To understand DNA organization and dynamics, it is important to consider the physical and topological constraints acting on it. In the eukaryotic cell nucleus, DNA is organized by proteins acting as spools on which DNA can be wrapped. These proteins can subsequently interact and form a structure called the chromatin fibre. Using a simple geometric model, we propose a general method for computing topological properties (twist, writhe and linking number) of the DNA embedded in those fibres. The relevance of the method is reviewed through the analysis of magnetic tweezers single molecule experiments that revealed unexpected properties of the chromatin fibre. Possible biological implications of these results are discussed.

Barbi, Maria; Mozziconacci, Julien; Victor, Jean-Marc; Wong, Hua; Lavelle, Christophe

2012-01-01

327

On the impulsive loading of muscle fibres  

NASA Astrophysics Data System (ADS)

Solutions of the basic equations governing the motion of a muscle fibre that include the damping effect of the surrounding material in addition to the elasticity and viscoelasticity of the fibre are obtained for step loading. By using separation of the variables it is shown that different types of solution are possible depending on the degree of damping present. Particular results are obtained for a finite fibre that is initially at rest and unstressed, has one end fixed for all time and is subjected to either a sudden displacement or a sudden force at the other end. Numerical results for the stress at a fixed end are obtained for frog skeletal muscle and presented in graphical form. A simple expression for the displacement is found to give a good description for moderately large times.

Eason, G.

1989-08-01

328

Retinal nerve fiber layer retardation measurements using a polarization-sensitive fundus camera.  

PubMed

To measure the retardation distribution of the optic retinal nerve fiber layer (RNFL) from a single image, we have developed a new polarization analysis system that is able to detect the Stokes vector using a fundus camera. The polarization analysis system is constructed with a CCD area image sensor, a linear polarizing plate, a microphase plate array, and a circularly polarized light illumination unit. In this system, the Stokes vector expressing the whole state of polarization is detected, and the influence of the background scattering in the retina and of the retardation caused by the cornea are numerically eliminated. The measurement method is based on the hypothesis that the retardation process of the eye optics can be quantified by a numerical equation that consists of a retardation matrix of all the polarization components. We show the method and the measurement results for normal eyes. Our results indicate that the present method may provide a useful means for the evaluation of retardation distribution of the RNFL. PMID:21806278

Fukuma, Yasufumi; Okazaki, Yoshio; Shioiri, Takashi; Iida, Yukio; Kikuta, Hisao; Shirakashi, Motohiro; Yaoeda, Kiyoshi; Abe, Haruki; Ohnuma, Kazuhiko

2011-07-01

329

Retinal nerve fiber layer retardation measurements using a polarization-sensitive fundus camera  

NASA Astrophysics Data System (ADS)

To measure the retardation distribution of the optic retinal nerve fiber layer (RNFL) from a single image, we have developed a new polarization analysis system that is able to detect the Stokes vector using a fundus camera. The polarization analysis system is constructed with a CCD area image sensor, a linear polarizing plate, a microphase plate array, and a circularly polarized light illumination unit. In this system, the Stokes vector expressing the whole state of polarization is detected, and the influence of the background scattering in the retina and of the retardation caused by the cornea are numerically eliminated. The measurement method is based on the hypothesis that the retardation process of the eye optics can be quantified by a numerical equation that consists of a retardation matrix of all the polarization components. We show the method and the measurement results for normal eyes. Our results indicate that the present method may provide a useful means for the evaluation of retardation distribution of the RNFL.

Fukuma, Yasufumi; Okazaki, Yoshio; Shioiri, Takashi; Iida, Yukio; Kikuta, Hisao; Shirakashi, Motohiro; Yaoeda, Kiyoshi; Abe, Haruki; Ohnuma, Kazuhiko

2011-07-01

330

Solvent Retention and Fibre Chemistry.  

National Technical Information Service (NTIS)

The aim of this study was to understand in which way different chemical and physical treatments affect the solvent retention properties of pulps used in the middle layer of folding boxboard. The solvent retention properties of the treated pulps were exami...

M. Rantanen

2003-01-01

331

Development of fibre-metal laminates for improved impact performance  

NASA Astrophysics Data System (ADS)

An analytical and experimental investigation into the low-velocity behaviour of GLARE Fibre-Metal Laminates (FMLs) has been performed. A quasi-static approach was developed to estimate the perforation energy absorbed between the constituents of GLARE. The analysis considered contact area increase during perforation and strain rate effect on material properties. Particular attention was paid to the effect of ply-angle orientation and aluminium position. Predicted maximum impact force, maximum displacement, and perforation energy related to impact velocity were within 10% of test results. Stacking composite plies oriented along the diagonal of the plate with more than 2 aluminium layers leads to a more impact resistant FML. The generic nature of the developed methodology can support the optimization of high-performance FML concepts.

Morinière, F. D.; Alderliesten, R. C.; Benedictus, R.

2012-05-01

332

Symmetric diffeomorphic registration of fibre orientation distributions.  

PubMed

Registration of diffusion-weighted images is an important step in comparing white matter fibre bundles across subjects, or in the same subject at different time points. Using diffusion-weighted imaging, Spherical Deconvolution enables multiple fibre populations within a voxel to be resolved by computing the fibre orientation distribution (FOD). In this paper, we present a novel method that employs FODs for the registration of diffusion-weighted images. Registration was performed by optimising a symmetric diffeomorphic non-linear transformation model, using image metrics based on the mean squared difference, and cross-correlation of the FOD spherical harmonic coefficients. The proposed method was validated by recovering known displacement fields using FODs represented with maximum harmonic degrees (l(max)) of 2, 4 and 6. Results demonstrate a benefit in using FODs at l(max)=4 compared to l(max)=2. However, a decrease in registration accuracy was observed when l(max)=6 was used; this was likely caused by noise in higher harmonic degrees. We compared our proposed method to fractional anisotropy driven registration using an identical code base and parameters. FOD registration was observed to perform significantly better than FA in all experiments. The cross-correlation metric performed significantly better than the mean squared difference. Finally, we demonstrated the utility of this method by computing an unbiased group average FOD template that was used for probabilistic fibre tractography. This work suggests that using crossing fibre information aids in the alignment of white matter and could therefore benefit several methods for investigating population differences in white matter, including voxel based analysis, tensor based morphometry, atlas based segmentation and labelling, and group average fibre tractography. PMID:21316463

Raffelt, David; Tournier, J-Donald; Fripp, Jurgen; Crozier, Stuart; Connelly, Alan; Salvado, Olivier

2011-02-18

333

Presynaptic Calcium Signalling in Cerebellar Mossy Fibres  

PubMed Central

Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX)-sensitive fast Na+ spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers. Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than 1?s affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be modulated locally, suggesting that cerebellar glomeruli may be dynamically sub-compartmentalized due to ongoing inhibition mediated by Golgi cells. This could provide a fine-grained control of mossy fibre-granule cell information transfer and synaptic plasticity within a mossy fibre rosette.

Thomsen, Louiza B.; Jorntell, Henrik; Midtgaard, Jens

2009-01-01

334

Muscle fibre characteristics in four muscles of growing bulls  

Microsoft Academic Search

Mammalian muscle fibres maturation follows a distinct programme lineage (I?IIC?IIA?(IID\\/X)?IIB). Changes in morphology, protein content and metabolic characteristics are related to several factors, age being one of the most crucial for muscle fibre type. Similarly, muscle fibre type affects overall muscle growth rate. The objective of this study was to characterise the profile of muscle fibre types and metabolic enzyme

Anna M Brandstetter; Brigitte Picard; Yves Geay

1998-01-01

335

Radiotherapy dosimetry based on plastic optical fibre sensors  

NASA Astrophysics Data System (ADS)

The use of a PMMA based plastic optical fibre in radiotherapy dosimetry is presented. The optical fibre tip is coated with a scintillation material, terbium-doped gadolinium oxysulfide (Gd2O2S:Tb), which fluoresces under ionising radiation. The emitted signal penetrates the fibre and propagates along the fibre where it is remotely monitored using a fluorescence spectrometer. The results demonstrate good repeatability, with a maximum percentage error of 0.59% and the response is independent of dose rate.

O'Keeffe, S.; Grattan, M.; Hounsell, A.; McCarthy, D.; Woulfe, P.; Cronin, J.; Lewis, E.

2013-05-01

336

Fire Retardancy of Natural Fibre Reinforced Sheet Moulding Compound  

Microsoft Academic Search

Due to environmental awareness and economical considerations, natural fibre reinforced polymer composites seem to present\\u000a a viable alternative to synthetic fibre reinforced polymer composites such as glass fibres. This is a feasibility study to\\u000a asses the potential application of natural fibre reinforced sheet moulding compound materials (NF-SMC) for the use in building\\u000a applications, with particular emphases to their reaction to

T. D. Hapuarachchi; G. Ren; M. Fan; P. J. Hogg; T. Peijs

2007-01-01

337

Processing with kW fibre lasers: advantages and limits  

Microsoft Academic Search

Up-to-date fibre lasers produce multi-kw radiation with an excellent beam quality. Compared to CO2-lasers, fibre lasers have relatively low operational costs and offer a very high flexibility in production due to the beam delivery with process fibres. As a consequence, fibre lasers have attracted more and more attention. On the other hand, their use in industrial applications especially in the

A. Kratky; D. Schuöcker; G. Liedl

2008-01-01

338

Improvement of fibre and composites for new markets  

Microsoft Academic Search

Plant fibres have decisive advantages compared with synthetic fibres. One great advantage of plant fibres is their optimized\\u000a strength to weight ratio. Others are their better workability as a result of optimum fibre length and cell wall thickness,\\u000a their high anisotropic qualities and their good ion exchange capacity. The natural products are readily biodegradable and\\u000a renewable.

Marcel Toonen; Michel Ebskamp; Robert Kohler

2006-01-01

339

Decreased Retinal Ganglion Cell Layer Thickness in Patients with Type 1 Diabetes  

PubMed Central

Purpose. To determine which retinal layers are most affected by diabetes and contribute to thinning of the inner retina and to investigate the relationship between retinal layer thickness (LT) and diabetes duration, diabetic retinopathy (DR) status, age, glycosylated hemoglobin (HbA1c), and the sex of the individual, in patients with type 1 diabetes who have no or minimal DR. Methods. Mean LT was calculated for the individual retinal layers after automated segmentation of spectral domain-optical coherence tomography scans of patients with diabetes and compared with that in control subjects. Multiple linear regression analysis was used to determine the relationship between LT and HbA1c, age, sex, diabetes duration, and DR status. Results. In patients with minimal DR, the mean ganglion cell layer (GCL) in the pericentral area was 5.1 ?m thinner (95% confidence interval [CI], 1.1–9.1 ?m), and in the peripheral macula, the mean retinal nerve fiber layer (RNFL) was 3.7 ?m thinner (95% CI, 1.3–6.1 ?m) than in the control subjects. There was a significant linear correlation (R = 0.53, P < 0.01) between GCL thickness and diabetes duration in the pooled group of patients. Multiple linear regression analysis (R = 0.62, P < 0.01) showed that DR status was the most important explanatory variable. Conclusions. This study demonstrates GCL thinning in the pericentral area and corresponding loss of RNFL thickness in the peripheral macula in patients with type 1 diabetes and no or minimal DR compared with control subjects. These results support the concept that diabetes has an early neurodegenerative effect on the retina, which occurs even though the vascular component of DR is minimal.

Verbraak, Frank D.; Kok, Pauline H. B.; Garvin, Mona K.; Sonka, Milan; Lee, Kyungmoo; DeVries, J. Hans; Michels, Robert P. J.; van Velthoven, Mirjam E. J.; Schlingemann, Reinier O.; Abramoff, Michael D.

2010-01-01

340

Effect of dietary fibre on nitrogen retention and fibre associated threonine losses in growing pigs.  

PubMed

Apart from being an energy source, dietary fibre is also discussed to act as anti-nutritional factor reducing apparent precaecal protein and amino acid (AA) digestibility due to reduced absorption or increased endogenous secretion or both. However, the amounts of protein and AA of endogenous origin determined at the terminal ileum in cannulated animals do not represent the total losses associated with endogenous secretion. A high proportion of secreted protein is reabsorbed and does not reach the terminal ileum, and losses occur during synthesis of endogenous protein. Therefore, the present study used an alternative indirect approach, taking the reduction of nitrogen (N) retention in a threonine (Thr) limited diet as a sensitive indicator for fibre-associated Thr losses. Two experiments were conducted with 12 castrated male pigs each between 37 and 75 kg body weight to measure the effect of the intake of Thr and 150 and 300 g/d fibre from wheat bran (Exp. 1), or 150 g/d fibre from rape seed, cassava leaves, and cassava root peels, respectively (Exp. 2), on N retention. During two (Exp. 1) and three (Exp. 2) balance periods the animals were subjected to the dietary treatments according to a cross-over design. All animals received 1350 g/d of a wheat-soybean-based diet supplemented with free AA to ensure Thr being the first-limiting AA. To determine the effect of Thr on N retention, intake of the basal diet was reduced to 1150 g/d and supplemented with corn starch to reach equal energy intake and an unchanged AA pattern. With increasing BW additional starch was added to all diets to ensure a constant energy intake of 1.25 MJ ME/kg BW(0.75). Since the fibre sources contained small amounts of Thr, N retentions were corrected for precaecal digestible Thr intake originating from the fibre sources according to the Thr effect on N retention as determined in experiment 1. Corrected N retentions were affected by fibre level (p = 0.007) and source (p < 0.001). Fibre-associated Thr losses amounted to 3.3, 3.2, 1.2, and 1.1 g/kg fibre from wheat bran, rapeseed, cassava leaf, and cassava root peel, respectively. It is concluded that Thr losses per gram of dietary fibre depend on the fibre source and that fibre concentration and source in pig diets should be considered as a factor affecting Thr requirement. PMID:22641922

Blank, Britta; Schlecht, Eva; Susenbeth, Andreas

2012-04-01

341

Inscription of fibre Bragg gratings in non-sensitised fibres using VUV F2 laser radiation.  

PubMed

We report the inscription of fibre Bragg gratings in non-sensitised SMF 28 and HI 980 fibre by exposure to VUV F2 laser radiation at 157 nm. The modulated effective refractive index change Deltan(eff) deduced from the shift in the grating reflection peaks was Deltan(eff) = 2.8x10(-4) and 1.7x10(-4) in SMF 28 and HI 980 fibre respectively. The possible influence of non-uniformity of core exposure and VUV cladding absorption loss on these results is discussed. PMID:19582023

Dyer, P E; Johnson, A M; Walton, C D

2008-11-10

342

A textile fibre survey as an aid to the interpretation of fibre evidence in the Sydney region.  

PubMed

Frequency figures of the fibre population on textile cinema seats were measured in Sydney, Australia, in winter. Sixteen seats were analysed from a very popular cinema complex, with 3025 fibres classified according to colour, generic class and fluorescence properties (100 grey-black cotton fibres only). The recovered fibres were mostly natural fibres (84%) with cotton the most common generic type (70%). On the contrary, man made fibres were relatively rare (15%) with rayon constituting the majority of these (51%). The most common colour/generic class combinations were grey-black cotton (33%) and blue cotton (30%) accounting for 63% of the total population. All other frequencies were below 5%, most below 1% using only the two properties of colour and generic class. Fluorescence properties were found to be very discriminating as far as grey-black cotton fibres were concerned. These features are considered and discussed and in particular, to emphasise the significance of fibres as evidence of contact. PMID:11731196

Cantrell, S; Roux, C; Maynard, P; Robertson, J

2001-11-15

343

Temperature dependence of the stress response of fibre Bragg gratings  

Microsoft Academic Search

Fibre Bragg gratings, used as stress sensing elements, show a temperature dependence of their stress response, which is mainly characterized by Young's modulus of the fibre material. The temperature dependence of the stress response of a fibre Bragg grating over a range from -38 °C to +110 °C has been measured. The stress sensitivity decreases linearly by 1.22 × 10-4

Robert R. J. Maier; William N. MacPherson; James S. Barton; Julian D. C. Jones; Scott McCulloch; Gary Burnell

2004-01-01

344

Clothing as a source of fibres within museums  

Microsoft Academic Search

This paper examines the role of visitors’ clothing as a source of fibres and dust in museums. Some idealised experiments determined the mass of fibres and dust emitted from clothing and the range of particle sizes found. In chamber studies it was possible to examine the effect of different humidity and airflow on fibre release. Image analysis was used to

Young Hun Yoon; Peter Brimblecombe

2000-01-01

345

Influence of chemical treatments on adhesion properties of hemp fibres  

Microsoft Academic Search

In addition to be an environmentally friendly material, hemp fibres are also inexpensive reinforcements in thermoplastics or concrete composites, due to their intrinsic mechanical, thermal and acoustic properties. The morphology of hemp fibres has been chemically modified in order to enhance the matrix\\/fibre interface and has been examined by Scanning Electron Microscopy (SEM). In this paper, Gas Chromatography (GC) and

M. Le Troëdec; A. Rachini; C. Peyratout; S. Rossignol; E. Max; O. Kaftan; A. Fery; A. Smith

2011-01-01

346

Nanometre diameter fibres of polymer, produced by electrospinning  

Microsoft Academic Search

Electrospinning uses electrical forces to produce polymer fibres with nanometre-scale diameters. Electrospinning occurs when the electrical forces at the surface of a polymer solution or melt overcome the surface tension and cause an electrically charged jet to be ejected. When the jet dries or solidifies, an electrically charged fibre remains. This charged fibre can be directed or accelerated by electrical

Darrell H. Reneker; Iksoo Chun

1996-01-01

347

Static and fatigue characterisation of new basalt fibre reinforced composites  

Microsoft Academic Search

Basalt reinforced composites are recently developed materials. These mineral amorphous fibres are a valid alternative to carbon fibres for their lower cost, and to glass fibres for their strength. In order to use basalt reinforced composites for structural applications, it is necessary to perform a mechanical characterisation. With this aim in the present work experimental results of several static and

C. Colombo; L. Vergani; M. Burman

348

Optical fibre sensors for monitoring of welding residual stresses  

Microsoft Academic Search

Transient and residual strains in the heat affected zone (HAZ) of a TIG arc welded aluminium–magnesium alloy test plate have been measured on line using fibre Bragg grating sensors. The optical fibre sensor operates as a reflection filter: when a light beam travelling along the fibre optic reaches the Bragg grating, only a certain wavelength will be reflected. The reflected

J. C Suárez; B Remart??nez; J. M Menéndez; A Güemes; F Molleda

2003-01-01

349

Development and characterisation of polyaniline - carbon nanotube conducting composite fibres  

Microsoft Academic Search

The present study describes methods for development and characterization of conducting electroactive polymer (CEP) fibre consisting of polyaniline (PAni) and single walled carbon nanotubes (SWNTs) which have potential applications as electronic devices to form building blocks of electronic textiles. The conducting composite fibres of PAni- SWNT were developed respectively using two steps (acid doping after fibre spinning) and one step

Vahid Mottaghitalab

2006-01-01

350

Delamination, fibre bridging and toughness of ceramic matrix composites  

Microsoft Academic Search

Delamination cracks in long-fibre reinforced ceramic matrix composites are found to be bridged by fibres which span the crack wake at a shallow angle. The in situ observation of bridging fibres reveals that these are subject to considerable tensile forces, giving rise to a substantial crack closure force. The overall crack closure force is determined by the number of bridging

D. A. W. Kaute; H. R. Shercliff; M. F. Ashby

1993-01-01

351

Golgi stain identifies three types of fibres in fish muscle  

Microsoft Academic Search

Summary Using Golgi infiltration we have studied the structure and disposition of tranverse tubules in muscle fibres from the sand dab fin musculature. Three types of fibres differ significantly from each other in the extent and disposition of junctions between transverse tubules and the sarcoplasmic reticulum. These correlate with the three groups of fibres having different relaxation times shown in

Clara Franzini-Armstrong; William F. Gilly; Eva Aladjem; Denah Appelt

1987-01-01

352

Compressive and torsional behaviour of Kevlar 49 fibre  

Microsoft Academic Search

The mechanical anisotropy of an aromatic polyamide fibre, Kevlar 49, was studied in tension, compression and torsion. A new technique involved applying small and defined compressive strains to filaments by bonding them to one side of a beam which is subsequently bent to compress the fibres. Using scanning electron and optical microscopy, fibres were shown to form regularly-spaced helical kink

S. J. Deteresa; S. R. Allen; R. J. Farris; R. S. Porter

1984-01-01

353

Microstructure and mechanical properties of pitch-based carbon fibres  

Microsoft Academic Search

The microstructure of a series of mesophase pitch-based carbon fibres have been examined using X-ray diffraction, electron microscopy and Raman spectroscopy. It has been shown that the mechanical properties of the fibres are related directly to the response of this microstructure to deformation and, in particular, that the Young's modulus and tensile strength of the fibres are controlled directly by

Yanling Huang; R. J. Young

1994-01-01

354

The thermal expansion of carbon fibre-reinforced plastics  

Microsoft Academic Search

Interferometric measurements of the linear thermal expansion coefficients of epoxy resin DLS 351\\/BF3400 are reported over the approximate temperature range 90 to 500 K. Corresponding measurements in directions parallel and perpendicular to the fibres are also reported for unidirectional composite bars of Courtaulds HTS carbon fibre in this resin, at nominal fibre volume contents of 50, 60 and 80%. The

B. Yates; M. J. Overy; J. P. Sargent; B. A. McCalla; D. M. Kingston-Lee; L. N. Phillips; K. F. Rogers

1978-01-01

355

Effect of fibre surface treatment on the mechanical response of ceramic fibre mat-reinforced interpenetrating vinylester\\/epoxy resins  

Microsoft Academic Search

A vinylester\\/epoxy (VE\\/EP ratio=1\\/1) hybrid resin of interpenetrating network (IPN) structure was reinforced by a needle punched ceramic fibre mat (30 wt%) composed of long discontinuous fibres (length ?50 mm). The surface chemistry of the ceramic fibres was varied by coating them with various organosilanes resulting in vinyl (VS) and epoxy (ES) functionalities. In addition, mats containing ceramic fibres without

J. S. Szabó; J. Karger-Kocsis; O. Gryshchuk; T. Czigány

2004-01-01

356

Pectin Methylesterase and Pectin Remodelling Differ in the Fibre Walls of Two Gossypium Species with Very Different Fibre Properties  

PubMed Central

Pectin, a major component of the primary cell walls of dicot plants, is synthesized in Golgi, secreted into the wall as methylesters and subsequently de-esterified by pectin methylesterase (PME). Pectin remodelling by PMEs is known to be important in regulating cell expansion in plants, but has been poorly studied in cotton. In this study, genome-wide analysis showed that PMEs are a large multi-gene family (81 genes) in diploid cotton (Gossypium raimondii), an expansion over the 66 in Arabidopsis and suggests the evolution of new functions in cotton. Relatively few PME genes are expressed highly in fibres based on EST abundance and the five most abundant in fibres were cloned and sequenced from two cotton species. Their significant sequence differences and their stage-specific expression in fibres within a species suggest sub-specialisation during fibre development. We determined the transcript abundance of the five fibre PMEs, total PME enzyme activity, pectin content and extent of de-methylesterification of the pectin in fibre walls of the two cotton species over the first 25–30 days of fibre growth. There was a higher transcript abundance of fibre-PMEs and a higher total PME enzyme activity in G. barbadense (Gb) than in G. hirsutum (Gh) fibres, particularly during late fibre elongation. Total pectin was high, but de-esterified pectin was low during fibre elongation (5–12 dpa) in both Gh and Gb. De-esterified pectin levels rose thereafter when total PME activity increased and this occurred earlier in Gb fibres resulting in a lower degree of esterification in Gb fibres between 17 and 22 dpa. Gb fibres are finer and longer than those of Gh, so differences in pectin remodelling during the transition to wall thickening may be an important factor in influencing final fibre diameter and length, two key quality attributes of cotton fibres.

Liu, Qinxiang; Talbot, Mark; Llewellyn, Danny J.

2013-01-01

357

Continuous Atmospheric Plasma Oxidation of Carbon Fibres: Influence on the Fibre Surface and Bulk Properties and Adhesion to Polyamide 12  

Microsoft Academic Search

Continuous atmospheric plasma oxidation (APO) was used to introduce oxygen functionalities to the surface of carbon fibres\\u000a in an attempt to enhance interfacial adhesion between carbon fibres and polyamide-12 (PA-12). APO only affects the surface\\u000a properties of the fibres while their bulk properties remained unchanged. Contact angle and ?-potential measurements demonstrated\\u000a that APO-treated fibres became significantly more hydrophilic due to

Seckin ErdenKingsley; Kingsley K. C. Ho; Steven Lamoriniere; Adam F. Lee; Hasan Yildiz; Alexander Bismarck

2010-01-01

358

A Pr 3+-doped ZBLAN fibre upconversion laser pumped by an Yb 3+-doped silica fibre laser  

Microsoft Academic Search

An Yb3+-doped silica fibre laser pumped at 840 nm has been used to provide the two pump wavelengths, 840 nm and 1020 nm, required for pumping a Pr3+-doped ZBLAN fibre upconversion laser. The performance of the upconversion laser at 491, 520 and 635 nm is presented, with measurements of fibre loss at 635 nm and 520 nm which indicate that

H. M Pask; A. C Tropper; D. C Hanna

1997-01-01

359

International Conference on Chemical Fibres. Chemical Fibres: Present and Future. Look at the Next Century. Part 2  

Microsoft Academic Search

The trends in the development of chemical fibre production processes are analyzed and the general characteristics of the change in their manufacture as a function of the fundamental determining factors are found. The characteristics of chemical fibre production processes and subsequent treatments are examined and the possibilities of optimizing and intensifying existing technologies and improving the properties of the fibres

K. E. Perepelkin

2000-01-01

360

Extended-range, low coherence dual wavelength interferometry using a superfluorescent fibre source and chirped fibre Bragg gratings  

Microsoft Academic Search

We describe an all-fibre, passive scheme for making extended range interferometric measurements based on the dual wavelength technique. The coherence tuned interferometer network is illuminated with a single superfluorescent fibre source at 1.55 ?m and the two wavelengths are synthesised at the output by means of chirped fibre Bragg gratings. We demonstrate an unambiguous sensing range of 270 ?m, with

G. P Brady; K. Kalli; D. J Webb; D. A Jackson; L. Zhang; I. Bennion

1997-01-01

361

Short natural-fibre reinforced polyethylene and natural rubber composites: Effect of silane coupling agents and fibres loading  

Microsoft Academic Search

Composites materials based on cellulose fibres (raw or chemically modified) as reinforcing elements and thermoplastic matrices were prepared and characterized, in terms of mechanical performances, thermal properties and water absorbance behaviour. Four different cellulose fibres with different average lengths were used, namely avicel, technical, alfa pulps and pine fibres. Two thermoplastic polymers, i.e. low density polyethylene and natural rubber, were

M. Abdelmouleh; S. Boufi; M. N. Belgacem; A. Dufresne

2007-01-01

362

Developments in the characterization of natural fibre properties and in the use of natural fibres for composites  

Microsoft Academic Search

All composite models contain the Young's modulus or the tensile strength of the reinforcing fibres. Therefore the essential prerequisite to come to an agreement between the theoretical approaches and the practical results is the exact measurement of these parameters. Some aspects of the measurement of the natural fibre E-modulus are discussed. Furthermore a new process to produce long fibre reinforced

Axel Nechwatal; Klaus-Peter Mieck; Thomas Reußmann

2003-01-01

363

Wood Fibre Reinforced Polypropylene Composites: Effect of Fibre Geometry and Coupling Agent on Physico-Mechanical Properties  

NASA Astrophysics Data System (ADS)

Wood fibre reinforced polypropylene composites at fibre content 50% by weight have been prepared and different types of wood fibres (hard wood fibre, soft wood fibre, long wood fibre and wood chips) were treated with coupling agent (MAH-PP) to increase the interfacial adhesion with the matrix to improve the dispersion of the particles and to decrease the water sorption properties of the final composite. The present study investigated the tensile, flexural, charpy impact and impact properties of wood fibre reinforced polypropylene composites as a function of coupling agent and fibre length and structure. From the results it is observed that wood chips-PP composites showed better tensile and flexural properties comparative with the other wood fibre-PP composites with the addition of 5%MAH-PP, which is around 65% and 50% for tensile strength and flexural strength respectively. Hard wood fibre-PP composites showed better impact characteristic values comparative to other wood fibre-PP composites with the addition of 5%MAH-PP and damping index decreased about to 60%. Charpy impact strength also increased up to 60% with the addition of 5%MAH-PP for long wood fibre-PP composites. Water absorption and scanning electron microscopy of the composites are also investigated.

Bledzki, Andrzej K.; Faruk, Omar

2003-11-01

364

Process monitoring of aluminum-foam sandwich structures based on thermoplastic fibre–metal laminates using fibre Bragg gratings  

Microsoft Academic Search

This paper reports the use of fibre Bragg gratings (FBGs) for monitoring the fabrication process in a novel sandwich structure based on thermoplastic fibre–metal laminate (FML) skins and an aluminum-foam core. The FBG sensors were embedded between two plies of glass fibre reinforced polypropylene within the FML and the shift in the Bragg wavelength was recorded during the fabrication cycle

K. S. C. Kuang; L. Zhang; W. J. Cantwell; I. Bennion

2005-01-01

365

Theoretical model of the influence of oxide overlayer thickness on the performance of a surface plasmon fibre-optic sensor  

NASA Astrophysics Data System (ADS)

Fibre-optic surface plasmon resonance (SPR) sensors have been proven to be a useful tool in various measurement tasks where the miniaturization, compactness and low cost are the essential requirements. Recently, it has been shown that the sensitivity of a SPR sensor can be improved if the metallic layer used for surface plasmon excitation is covered by a high-refractive index overlayer (for example, oxide or semiconductor). The semiconductor layer can protect the metal against oxidation, but when it is exposed to the atmosphere, a thin oxide layer can be formed on its top surface. This fact leads to a general question: how an oxide layer (naturally or thermally grown) affects the sensing? This paper deals with the influence of the oxide layer on the sensor performance. The analysed structure consists of a thin gold film covered by the partially oxidized silicon overlayer. The presented theoretical model of the fibre-optic SPR sensor is based on the optics of multilayered media and optical dispersion of all involved media is taken into account. The influence of oxide layer thickness change on the sensor performance in the wavelength domain is studied in detail. The computation of optical power transmitted through the sensing part of a multimode fibre is carried out in order to evaluate the response of the sensor in terms of sensitivity and detection accuracy.

Ciprian, D.; Hlubina, P.

2013-02-01

366

Sorptive removal of Methylene blue from aqueous solution using palm kernel fibre: Effect of fibre dose  

Microsoft Academic Search

The use of palm kernel fibre, a readily available agricultural waste product for the sorption of Methylene blue from aqueous solution and the possible mechanism of sorption has been investigated at various fibre doses. The extent of dye removal and the rate of sorption were analyzed using two kinetic rate models (pseudo-first and pseudo-second-order kinetic models) and two diffusion models

Augustine E. Ofomaja

2008-01-01

367

Realisation de composants tout-fibre passifs bases sur des fibres optiques a deux coeurs  

Microsoft Academic Search

Les composants passifs tout-optique sont des elements de choix dans les systemes de communications optiques. Cette these presente l'utilisation experimentale de fibres a deux coeurs dissimilaires pour la realisation de filtres passe-bande. Les fibres a deux coeurs ont la particularite de favoriser un couplage d'un coeur a l'autre a intervalles reguliers lorsque les coeurs sont exactement identiques. Dans le cas

Anne C. Jacob Poulin

2002-01-01

368

Pitch-based carbon fibres derived from thermoset fibres oxidized with Cl 2 containing air  

Microsoft Academic Search

Mesophase pitch-based carbon fibres thermoset with Cl2 containing air were studied for their microstructures and physical properties. Carbon fibres thermoset with Cl2 containing air and heat-treated at 2000‡C (Cl22000) possessed slightly smaller mean sizes of crystallites Lc(0 0 2)s, lower densities, lower tensile moduli of elasticity, and higher tensile strengths than those thermoset with air. X-ray diffraction measurements revealed a

T. Tomioka; Y. Arai; T. Hamada

1995-01-01

369

Left ventricular fibre architecture in man  

Microsoft Academic Search

In order to investigate the possibility of regional variation of ventricular structure, 25 normal postmortem human hearts were studied by inspection of cavity shape and subepicardial fibre orientation, by dissection, and by the histology of sections in two orthogonal planes. Ventricular architecture was complex. Inlet and outlet long axes were separated by 30 degrees in the left ventricle. In the

R. A. Greenbaum; S. Y. Ho; D. G. Gibson; A. E. Becker; R. H. Anderson

1981-01-01

370

The evidential value of black cotton fibres.  

PubMed

Forensic scientists are faced with the problem of estimating the frequency of cotton fibres recovered in casework, in relation to those in the general population. One way of doing this is to consider the degree of spectral variation that occurs within a "block of colour". When a spectral pattern occurs very frequently, the evidential value of the fibres may be so low, that it is not worth considering them as target fibres. Using UV-visible range microspectro-photometry (MSP) spectra were recorded from 88 known black cotton dyes and 225 samples of black cotton taken from various textiles. UV-visible spectra originating from sulphur dyes and from the great majority of reactive and direct dyes can be easily recognised. Vat dyes present a little more difficulty. The degree of spectral variation and consequent discriminating power of MSP varied according to the dye class, from 0.13 for sulphur dyes to 0.93 for reactive dyes. From 99 textiles dyed with reactive dyes, the spectra could be divided into at least 40 varieties showing that these fibres have a high degree of individuality. Within the few direct dyes (11.5%) that were encountered, one basic spectral form predominated, but a number of minor variations were observed. Spectral information below 400 nm (UV-range) is important for making distinctions and is critical in the case of direct dyes. PMID:11793882

Grieve, M C; Biermann, T W; Davignon, M

371

Two-frequency fibre Raman laser  

SciTech Connect

A new scheme of a fibre Raman laser emitting at two wavelengths is proposed. The scheme uses a one-stage Raman converter with the output Bragg grating with the reflectivity above 99%. Lasing at two wavelengths is achieved due to the overlap of the output emission spectrum with the reflection spectrum of the output Bragg grating. (lasers)

Paramonov, Vladimir M; Kurkov, Andrei S; Medvedkov, O I; Grukh, Dmitrii A; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2004-03-31

372

A novel multifunctional fibre optic sensor  

NASA Astrophysics Data System (ADS)

Whilst considerable progress continues to be made on the design and deployment of fibre optic sensors for chemical process monitoring and structural integrity assessment, the majority of these sensor designs can only impart information on one or two relevant measurands. For example, in the case of chemical process monitoring of advanced fibrereinforced composites involving thermosetting resins, it is generally appreciated that cross-linking kinetics can be influenced by a number of factors including the following: the stoichiometry of the reagents, temperature, surface chemistry of the substrate and presence or absence of contaminants. Thermosetting resins also shrink during the crosslinking process. When thermosets are used and processed above room temperature during the production of fibrereinforced composites, upon cooling back to ambient temperature, residual stress can develop due to the mismatch in thermal expansions between the reinforcing fibres and the matrix. This paper reports on recent progress on the design and demonstration of a novel multi-functional fibre optic sensor that can provide data on (i) temperature, (ii) strain, (iii) refractive index, (iv) transmission infrared spectroscopy and (v) evanescent wave spectroscopy. A unique and attractive feature of this sensor is that a conventional commercially available Fourier transform infrared spectrometer is used to interrogate the sensor. The sensor design is based on an extrinsic fibre Fabry-Perot interferometer.

Mahendran, Ramani S.; Machavaram, Venkata R.; Wang, Liwei; Burns, Jonathan M.; Harris, Dee; Kukureka, Stephen N.; Fernando, Gerard F.

2009-03-01

373

Thermoplastic pultrusion of natural fibre reinforced composites  

Microsoft Academic Search

Thanks to the good mechanical properties and the ecological and environmental advantages, the natural fibre flax offers good opportunities as a reinforcement material for composites, especially thermoplastic ones. One technique for the manufacture of composites on a continuous basis is pultrusion. This paper describes the possibility of the use of flax as reinforcement in thermoplastic pultruded composites.

Kathleen Van de Velde; Paul Kiekens

2001-01-01

374

Development of novel nanostructured conducting polypyrrole fibres  

Microsoft Academic Search

Polypyrrole (PPy) as a conducting polymer has potential applications in electrical and electronic devices because of its high electrical conductivity, environmental stability and redox activity. There have been many attempts to endow electrically PPy with processibility. Although some success has been achieved via synthesising soluble PPy, there have remained difficulties to fabricate this material through fibre spinning due to its

Javad Foroughi

2009-01-01

375

Electron beam irradiated textile cellulose fibres  

Microsoft Academic Search

Powdered samples of cotton, flax and viscose from textile fibres were subjected to electron beam irradiation (20–400KGy). ESR signals were observed after irradiation. The intensity of the signals depended on the administered dose and exhibited an exponential decay with time. The ESR spectra, whose pattern depended drastically on the crystallinity of the samples, indicated the simultaneous presence of at least

A. Alberti; S. Bertini; G. Gastaldi; N. Iannaccone; D. Macciantelli; G. Torri; E. Vismara

2005-01-01

376

The Transverse Compression of Anisotropic Fibre Monofilaments  

Microsoft Academic Search

A synthetic fibre monofilament was compressed between transparent flats mounted on a microscope stage, and an image of the contact area thrown onto a screen. The contact area was determined as a function of load for polyethylene terephthalate, polypropylene and nylon monofilaments. These monofilaments can be regarded as transversely isotropic elastic cylinders and show considerable anisotropy, the extensional modulus being

D. W. Hadley; I. M. Ward; J. Ward

1965-01-01

377

Scintillating fibre hodoscopes for COSY-TOF  

SciTech Connect

At the cooler synchrotron COSY (Forschungszentrum Juelich, Germany) detector arrays of scintillating fibres are used in different experiments. In this contribution we mainly report on the experience with scintillating fibre hodoscopes in the COSY Time-of-Flight (TOF) spectrometer. One of the physical topics in this experiment is the study of the associated strangeness production in the reactions pp{yields}K{sup +}{lambda}p, K{sigma}{sup +}n, K{sup +}{sigma}{sup 0}p and K{sup 0}{sigma}{sup +}p. The apparatus consists of an inner start detector system close to the target and an outer stop detector system both mounted inside a vacuum vessel. For the inner detector system apart from microstrip components arrays of scintillating fibres are used to measure particle tracks and the decay vertices of the hyperons, thus allowing to identify and reconstruct the events of interest. Furthermore, scintillating fibre hodoscopes are installed for the online measurement of profiles and intensity of the proton beam at COSY-TOF. In both mentioned detector systems squared fibers are in operation together with multianode photomultipliers.

Eyrich, W.; Fritsch, M.; Hauffe, J.; Metzger, A.; Stinzing, F.; Wagner, M.; Wirth, S. [Physikalisches Institut, Universitaet Erlangen-Nuernberg, D-91058 Erlangen (Germany)

1998-11-09

378

Deformation of notched carbon fibre composites  

Microsoft Academic Search

A recently developed moiré technique was used to study in-plane surface displacements in notched carbon fibre composite plates under a tensile load. Elastic strains near a transverse notch in a unidirectional specimen were compared with the theoretical results for a homogeneous orthotropic sheet. Displacements and strains were obtained near shear cracks which developed at the notch tips in unidirectional and

S M Bishop

1974-01-01

379

Polyaniline hollow fibres for organic solvent nanofiltration.  

PubMed

Intrinsically-skinned asymmetric PANi hollow fibres, fabricated using a process of directly adding large organic acids to highly concentrated PANi solutions, show stability in a wide variety of organic solvents and have shown promising nanofiltration properties, giving high rejections of nanosolutes in acetone. PMID:19048143

Loh, Xun Xing; Sairam, Malladi; Steinke, Joachim Hans Georg; Livingston, Andrew Guy; Bismarck, Alexander; Li, Kang

2008-10-20

380

The tensile properties of single sugar palm (Arenga pinnata) fibre  

NASA Astrophysics Data System (ADS)

This paper presents a brief description and characterization of the sugar palm fibres, still rare in the scientific community, compared to other natural fibres employed in polymeric composites. Sugar palm fibres are cellulose-based fibres extracted from the Arenga pinnata plant. The characterization consists of tensile test and the morphological examination. The average tensile properties results of fibres such as Young's modulus is equal to 3.69 GPa, tensile strength is equal to 190.29 MPa, and strain at failure is equal to 19.6%.

Bachtiar, D.; Sapuan, S. M.; Zainudin, E. S.; Khalina, A.; Dahlan, K. Z. M.

2010-05-01

381

Polarisation characteristics of light from multimode optical fibres  

SciTech Connect

The polarisation beats accompanying decay of LP-mode groups in multimode optical fibres with a step refractive index profile are considered. The theoretical dependences of the degree of linear polarisation on the optical fibre length and light exit angle are determined based on the waveguide properties of these groups. The results obtained are compared with the existing theoretical concepts. It is shown that the light emerging from a multimode optical fibre near its axis can retain linear polarisation in fibres up to several meters long. Some experimental results are reported, which confirm the basic theoretical conclusions. (optical fibres)

Kiesewetter, Dmitrii V [St. Petersburg State Technical University, St. Petersburg (Russian Federation)

2010-08-27

382

Optical properties of fibres with aluminophosphosilicate glass cores  

SciTech Connect

The optical properties of fibres with aluminophosphosilicate (APS) glass cores have been studied at Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} concentrations varied independently from 0 to 20%, and the ranges of dopant concentrations that ensure an optical loss level acceptable for the fabrication of active fibres have been established. The origin of the increased losses observed previously in APS fibres containing excess phosphorus pentoxide has been identified, and the contamination source responsible for such losses in our fibres has been eliminated. (optical fibres)

Bubnov, M M; Zotov, K V; Iskhakova, L D; Lavrishchev, S V; Likhachev, M E; Rybaltovsky, A A; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Gur'yanov, Aleksei N; Lipatov, D S; Khopin, V F; Yashkov, M V [Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

2009-09-30

383

Effect of TiN nano-coating on the interface microstructure of carbon fibres-AZ91 alloy composite  

NASA Astrophysics Data System (ADS)

Magnesium matrix composites reinforced with carbon fibres, Cf, without surface modification and coated with TiN nanolayer, (Cf)TiN, were investigated. AZ91 magnesium alloy and carbon fibres of T300B (Toray) PAN type were chosen as components. In the experiment infiltration in vacuum as a method of component consolidation and chemical vapour deposition (CVD) for carbon fibres surface modification were applied. Structural investigations were performed in the Hitachi 3200S field-emission scanning electron microscope (FE-SEM) and on a FEI Tecnai G2 FEG high-resolution transmission electron microscope (TEM) equipped with energy-dispersive X-ray spectrometer (EDS) and high angle annular dark field (HAADF) detectors. SEM observations revealed that at the interface of AZ91-Cf composite destructive phases were formed. An application of TiN nano-coating as a surface modification ensured proper wettability of carbon fibres by liquid metal and protection against the destructive products formation. The microstructure of AZ91-(Cf)TiN composite interface was multilayered. TEM investigation revealed a continuous layer of mixed alumina and magnesia just at the carbon surface, followed by a layer with a dominant concentration of titanium, enriched with Al, O, Mg and C and subsequently a layer of nano-sized Al12Mg17 crystals in the magnesium matrix. Therefore, an applied TiN nano-coating can be classified as an active barrier in AZ91-Cf system.

Olszówka-Myalska, A.; Botor-Probierz, A.

2012-03-01

384

Histological analysis of fibres in myotomes of antarctic fish. II. Morphometry of muscle fibres and capillaries.  

PubMed

In a survey of nine species of antarctic Teleosts belonging to the families Chaenichthyidae (two species) and Nototheniidae (seven species) the surface density (Sv), volume density (Vv), number of muscle fibres and capillaries in 0.1 mm2 area and the diameters of capillaries were estimated. Muscle fibre to capillary ratio (C:F) and streamlinedness (1/h) of the fish were also calculated. It was found that the Sv values of the muscle fibres are inversely correlated with streamlinedness of the fish. However, this relation is disturbed in these fish which have low metabolic activity. In the genera Notothenia and Dissostichus only the Sv of the muscle fibres is greater in the caudal myotomes in comparison with those in the trunk. The capillarization of the muscle tissue in white-and red-blooded fish does not differ significantly, it differs however, in the case of musculus lateralis magnus (MLM) and musculus rectus lateralis (MRL). Capillary to fibre ratio (C:F) significantly differs between red and white portion of muscle in all species investigated. The diameters of white-blooded fish capillaries are importantly greater in comparison with those of red-blooded fish. It is concluded that muscles of white-blooded fish are morphologically adapted to the lack of hemoglobin and myoglobin by: relatively large diameters of their capillaries, but not by their density, and by the low Sv values of their muscle fibres. PMID:7168239

Kilarski, W; Smia?owska, E; Friedhuber, A

1982-01-01

385

Evaluation of the criteria to identify single-fibre potentials in human muscle fibres.  

PubMed

The criterion normally used to identify a potential generated by a single muscle fibre (SFAP) is that it must have identical shape at consecutive discharges. Technical problems accompanying the recording of single-fibre electromyographic (SFEMG) potentials introduce certain variability in the shape of these potentials, thereby compromising the ability to detect pure SFAPs. This study aims to determine the conditions necessary for two fibres to generate a compound potential that fulfils the single-fibre criterion. This has been done by analysing the alterations in the waveform of compound spikes formed by the summation of two SFAPs whose relative weight in the composite potential can differ considerably. Several factors responsible for this shape variability, with a geometrical, physiological or accidental origin, have been included in our study. It has been shown that a distant interfering component will be hardly detected in the composite potential if it is smaller than approximately 15 % of the main component. For this interfering component to generate a notch in the rising phase of the compound potential, it must be greater than about 30 % of the main component. A compound potential will fulfil the single-fibre criterion if the time dispersion between the individual components is less than 80-120 ?s. These results permit the estimation of the amplitude of interfering potentials so they could be useful in fibre density studies. The article also emphasises the inherent variability of SFEMG potentials and the impact of this variability on jitter estimation. PMID:22806128

Rodriguez-Falces, Javier; Gila, Luis; Dimitrova, Nonna Alexandrovna

2012-07-18

386

Fabrication of a submicron-channel organic field-effect transistor using a controllable electrospun single fibre as a shadow mask.  

PubMed

We demonstrate a simple and versatile method for the fabrication of a submicron channel for an organic field-effect transistor (OFET) using a single electrospun fibre as a shadow mask. A single electrospun fibre is produced by an alternative switching electrospinning method and is stretched 2.5-fold. The average diameter of the stretched fibres is 302 nm. The stretched fibre is placed on ultrathin dielectric layers of aluminium oxide and a self-assembled monolayer (SAM). During electrode deposition the fibre acts as a very small shadow mask. After removing the fibre, electrodes with very narrow gaps of around 350 nm and with high uniformity are easily obtained. We fabricate an OFET by depositing pentacene as an active layer onto the electrodes. The OFET is operable at low voltages, with a threshold voltage of - 1.1 V and a subthreshold swing of 0.27 V decade(-1), values which are one order of magnitude lower than those obtained with a channel length of 75 µm. PMID:21444947

Ishii, Y; Sakai, H; Murata, H

2011-03-28

387

Fabrication of a submicron-channel organic field-effect transistor using a controllable electrospun single fibre as a shadow mask  

NASA Astrophysics Data System (ADS)

We demonstrate a simple and versatile method for the fabrication of a submicron channel for an organic field-effect transistor (OFET) using a single electrospun fibre as a shadow mask. A single electrospun fibre is produced by an alternative switching electrospinning method and is stretched 2.5-fold. The average diameter of the stretched fibres is 302 nm. The stretched fibre is placed on ultrathin dielectric layers of aluminium oxide and a self-assembled monolayer (SAM). During electrode deposition the fibre acts as a very small shadow mask. After removing the fibre, electrodes with very narrow gaps of around 350 nm and with high uniformity are easily obtained. We fabricate an OFET by depositing pentacene as an active layer onto the electrodes. The OFET is operable at low voltages, with a threshold voltage of - 1.1 V and a subthreshold swing of 0.27 V decade - 1, values which are one order of magnitude lower than those obtained with a channel length of 75 µm.

Ishii, Y.; Sakai, H.; Murata, H.

2011-05-01

388

Development of an electrically tuneable Bragg grating filter in polymer optical fibre operating at 1.55 µm  

NASA Astrophysics Data System (ADS)

We present a thorough study on the development of a polymer optical fibre-based tuneable filter utilizing an intra-core Bragg grating that is electrically tuneable, operating at 1.55 µm. The Bragg grating is made tuneable using a thin-film resistive heater deposited on the surface of the fibre. The polymer fibre was coated via the photochemical deposition of a Pd/Cu metallic layer with the procedure induced by VUV radiation at room temperature. The resulting device, when wavelength tuned via Joule heating, underwent a wavelength shift of 2 nm for a moderate input power of 160 mW, a wavelength to input power coefficient of -13.4 pm mW-1 and time constant of 1.7 s-1. A basic theoretical study verified that for this fibre type one can treat the device as a one-dimensional system. The model was extended to include the effect of input electrical power changes on the refractive index of the fibre and subsequently to changes in the Bragg wavelength of the grating, showing excellent agreement with the experimental measurements.

Kalli, K.; Dobb, H. L.; Webb, D. J.; Carroll, K.; Themistos, C.; Komodromos, M.; Peng, G.-D.; Fang, Q.; Boyd, I. W.

2007-10-01

389

Acidity sensor based on porphyrin self-assembled monolayers covalently attached to the surfaces of tapered fibres  

NASA Astrophysics Data System (ADS)

Surface organization and photochemistry of free-base porphyrin self-assembled monolayers (SAMs) covalently bonded to the surfaces of tapered optical fibres and reference glass plates were studied. The surface modification was carried out in two steps: (i) surface activation by aminopropyltrimethoxysilane and (ii) porphyrin attachment via activated pentafluorophenyl esters. The measurements of surface activation time and real-time porphyrin adsorption monitoring revealed that each of the two steps required 1 h reaction time. Porphyrin immobilization on fibres was as good as on plane glass substrates. Fluorescence measurements were used to determine the optimum diameter of the coned part of the tapered fibre for sensor applications. For 125 µm fibres with a 10 µm cladding layer, this diameter was found to be 35-48 µm. The mono- and diprotonated forms of free-base porphyrin have distinct fluorescence spectra. This phenomenon was employed to demonstrate a pH sensor application of the SAM-modified tapered fibre, which operates in the pH range of 0.6-3.8.

Veselov, A.; Thür, C.; Efimov, A.; Guina, M.; Lemmetyinen, H.; Tkachenko, N.

2010-11-01

390

Composites for bone repair: phosphate glass fibre reinforced PLA with varying fibre architecture.  

PubMed

Internal fixation for bone fractures with rigid metallic plates, screws and pins is a proven operative technique. However, refracture's have been observed after rigid internal fixation with metal plates and plate fixation has been known to cause localised osteopenia under and near the plate. In the present study, resorbable composites comprising a PLA matrix reinforced with iron doped phosphate glass fibres were investigated. Non-woven random mat laminates of approximately 30% and 45% fibre volume fraction (V(f)) were produced, along with unidirectional and 0°-90° samples of approximately 20% V(f). The non-woven composite laminates achieved maximum values of 10 GPa modulus and 120 MPa strength. The 0-90º samples showed unexpectedly low strengths close to matrix value (~50 MPa) although with a modulus of 7 GPa. The UD specimens exhibited values of 130 MPa and 11.5 GPa for strength and modulus respectively. All the modulus values observed were close to that expected from the rule of mixtures. Samples immersed in deionised water at 37°C revealed rapid mechanical property loss, more so for the UD and 0-90º samples. It was suggested that continuous fibres wicked the degradation media into the composite plates which sped up the deterioration of the fibre-matrix interface. The effect was less pronounced in the non-woven random mat laminates due to the discontinuous arrangement of fibres within the composite, making it less prone to wicking. Random mat composites revealed a higher mass loss than the UD and 0°-90° specimens, it was suggested this was due to the higher fibre volume fractions of these composites and SEM studies revealed voidage around the fibres by day 3. Studies of pH of the degradation media showed similar profiles for all the composites investigated. An initial decrease in pH was attributed to the release of phosphate ions into solution followed by a gradual return back to neutral. PMID:21671001

Ahmed, I; Jones, I A; Parsons, A J; Bernard, J; Farmer, J; Scotchford, C A; Walker, G S; Rudd, C D

2011-06-14

391

Acoustical model of a Shoddy fibre absorber  

NASA Astrophysics Data System (ADS)

Shoddy fibres or "Shoddies" are a mixture of post-consumer and post-industrial fibres diverted from textile waste streams and recycled into their raw fibre form. They have found widespread use as a raw material for manufacturing sound absorbers that include, but are not limited to: automotive, architectural and home appliance applications. The purpose of this project is to develop a simple acoustic model to describe the acoustic behaviour of sound absorbers composed primarily of Shoddy fibres. The model requires knowledge of the material's bulk density only. To date, these materials have not been the focus of much published research and acoustical designers must rely on models that were developed for other materials or are overly complex. For modelling purposes, an equivalent fluid approach is chosen to balance complexity and accuracy. In deriving the proposed model, several popular equivalent fluid models are selected and the required input parameters for each model identified. The models are: the model of Delaney and Bazley, two models by Miki, the model of Johnson in conjunction with the model of Champoux and Allard and the model of Johnson in conjunction with the model of Lafarge. Characterization testing is carried out on sets of Shoddy absorbers produced using three different manufacturing methods. The measured properties are open porosity, tortuosity, airflow resistivity, the viscous and thermal characteristic lengths and the static thermal permeability. Empirical relationships between model parameters and bulk density are then derived and used to populate the selected models. This yields several 'simplified' models with bulk density as the only parameter. The most accurate model is then selected by comparing each model's prediction to the results of normal incidence sound absorption tests. The model of Johnson-Lafarge populated with the empirical relations is the most accurate model over the range of frequencies considered (approx. 300 Hz - 4000 Hz) Characterization testing yields specific values for intrinsic material parameters that allow for comparison to other porous materials. Individual parameter relations allow users to substitute measured or theoretical values as needed. A new empirical acoustical model is proposed to describe the behaviour of Shoddy-based fibre absorbers. The model requires knowledge of the bulk density only. This parameter is easily measured making application of the model elementary. Mots-clés : Shoddy, porous, fibre, recycled, absorption, model, acoustic.

Manning, John Peter

392

Astronomical optical frequency comb generation in nonlinear fibres and ring resonators: optimization studies  

NASA Astrophysics Data System (ADS)

We here discuss recent progress on astronomical optical frequency comb generation at innoFSPEC-Potsdam. Two different platforms (and approaches) are numerically and experimentally investigated targeting medium and low resolution spectrographs at astronomical facilities in which innoFSPEC is currently involved. In the first approach, a frequency comb is generated by propagating two lasers through three nonlinear stages - the first two stages serve for the generation of low-noise ultra-short pulses, while the final stage is a low-dispersion highly-nonlinear fibre where the pulses undergo strong spectral broadening. In our approach, the wavelength of one of the lasers can be tuned allowing the comb line spacing being continuously varied during the calibration procedure - this tuning capability is expected to improve the calibration accuracy since the CCD detector response can be fully scanned. The input power, the dispersion, the nonlinear coefficient, and fibre lengths in the nonlinear stages are defined and optimized by solving the Generalized Nonlinear Schrodinger Equation. Experimentally, we generate the 250GHz line-spacing frequency comb using two narrow linewidth lasers that are adiabatically compressed in a standard fibre first and then in a double-clad Er/Yb doped fibre. The spectral broadening finally takes place in a highly nonlinear fibre resulting in an astro-comb with 250 calibration lines (covering a bandwidth of 500 nm) with good spectral equalization. In the second approach, we aim to generate optical frequency combs in dispersion-optimized silicon nitride ring resonators. A technique for lowering and flattening the chromatic dispersion in silicon nitride waveguides with silica cladding is proposed and demonstrated. By minimizing the waveguide dispersion in the resonator two goals are targeted: enhancing the phase matching for non-linear interactions and producing equally spaced resonances. For this purpose, instead of one cladding layer our design incorporates two layers with appropriate thicknesses. We demonstrate a nearly zero dispersion (with +/- 4 ps/nm-km variation) over the spectral region from 1.4 to 2.3 microns. The techniques reported here should open new avenues for the generation of compact astronomical frequency comb sources on a chip or in nonlinear fibres.

Chavez Boggio, J. M.; Fremberg, T.; Bodenmüller, D.; Wysmolek, M.; Sanyic, H.; Fernando, H.; Neumann, J.; Kracht, D.; Haynes, R.; Roth, M. M.

2012-09-01

393

Towards multimaterial multifunctional fibres that see, hear, sense and communicate.  

PubMed

Virtually all electronic and optoelectronic devices necessitate a challenging assembly of conducting, semiconducting and insulating materials into specific geometries with low-scattering interfaces and microscopic feature dimensions. A variety of wafer-based processing approaches have been developed to address these requirements, which although successful are at the same time inherently restricted by the wafer size, its planar geometry and the complexity associated with sequential high-precision processing steps. In contrast, optical-fibre drawing from a macroscopic preformed rod is simpler and yields extended lengths of uniform fibres. Recently, a new family of fibres composed of conductors, semiconductors and insulators has emerged. These fibres share the basic device attributes of their traditional electronic and optoelectronic counterparts, yet are fabricated using conventional preform-based fibre-processing methods, yielding kilometres of functional fibre devices. Two complementary approaches towards realizing sophisticated functions are explored: on the single-fibre level, the integration of a multiplicity of functional components into one fibre, and on the multiple-fibre level, the assembly of large-scale two- and three-dimensional geometric constructs made of many fibres. When applied together these two approaches pave the way to multifunctional fabric systems. PMID:17471274

Abouraddy, A F; Bayindir, M; Benoit, G; Hart, S D; Kuriki, K; Orf, N; Shapira, O; Sorin, F; Temelkuran, B; Fink, Y

2007-05-01

394

Comparison of cytotoxicity of man-made vitreous fibres.  

PubMed

The purpose of the study was to compare the cytotoxicity of man-made vitreous fibres (MMVFs): four refractory ceramic fibres (RCFs 1-4), two glasswool fibres (MMVF 10 and 11), a rockwool fibre (MMVF 21) and a slagwool fibre (MMVF 22). The ability of the fibres to induce haemolysis in sheep erythrocytes, to release lactate dehydrogenase (LDH) from rat alveolar macrophages (AM) and to increase the production of reactive oxygen metabolites (ROMs) in human polymorphonuclear leukocytes (PML) was studied. To assess the relative cytotoxicity of MMVFs, their toxicity was compared with that induced by quartz, chrysotile or titanium dioxide. MMVFs induced a modest, but dose-dependent, increase of haemolysis at doses of 0.5, 2.5 and 5.0 mg ml-1. The amount of haemolysis and LDH release induced by MMVFs was generally similar to that induced by titanium dioxide. Glasswool fibre MMVF 10 induced less LDH release from rat AM than rockwool MMVF 21 or slagwool MMVF 22 fibres, whereas glasswool fibre MMVF 11 induced less LDH release than slagwool fibre MMVF 22 (P < 0.05). All fibres also dose-dependently increased the production of ROMs at doses between 25 and 500 micrograms ml-1. The shapes of the time-courses of MMVF-induced production of ROMs suggest that the mechanisms whereby the different fibres induce ROM production may exhibit similar features. There are clear-cut differences in the potency of various MMVFs to induce cytotoxicity and oxidative burst. The present results also emphasize the importance of using several measures of toxicity when assessing the biological activity of various fibres in vitro. PMID:9072949

Luoto, K; Holopainen, M; Sarataho, M; Savolainen, K

1997-01-01

395

An optical fibre with a conic aperture  

NASA Astrophysics Data System (ADS)

Light ray paths in an optical fibre with a conic hole at one of its extremes are studied, by means of geometrical optics, in connection with the aim of transferring the maximum amount of radiant energy from a concentrated light source to a solar trap. This particular application is useful in sunlight collecting systems which are able to concentrate light rays in a spot of small dimensions. The geometry of the optical fibre cable is such to allow multiple reflections of light rays on the external surface of the light guide, when its hollow extreme is placed in the proximity of the concentrated light spot. The simplicity of both the structure of the proposed optical system and of the analytic approach followed makes the present work useful in physics education.

DeLuca, R.

2006-09-01

396

Fibre Optic Sensors for Selected Wastewater Characteristics  

PubMed Central

Demand for online and real-time measurements techniques to meet environmental regulation and treatment compliance are increasing. However the conventional techniques, which involve scheduled sampling and chemical analysis can be expensive and time consuming. Therefore cheaper and faster alternatives to monitor wastewater characteristics are required as alternatives to conventional methods. This paper reviews existing conventional techniques and optical and fibre optic sensors to determine selected wastewater characteristics which are colour, Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). The review confirms that with appropriate configuration, calibration and fibre features the parameters can be determined with accuracy comparable to conventional method. With more research in this area, the potential for using FOS for online and real-time measurement of more wastewater parameters for various types of industrial effluent are promising.

Chong, Su Sin; Abdul Aziz, A. R.; Harun, Sulaiman W.

2013-01-01

397

Quantum theory of fibre Bragg grating solitons  

NASA Astrophysics Data System (ADS)

Following the pioneering work of Professor Haus, a general quantum theory for bi-directional nonlinear optical pulse propagation problems is developed and applied to study the quantum properties of fibre Bragg grating solitons. Fibre Bragg grating solitons are found to be automatically amplitude squeezed after passing through the grating and the squeezing ratio saturates after a certain grating length. The optimal squeezing ratio occurs when the pulse energy is slightly above the fundamental soliton energy. One can also compress the soliton pulsewidth and enhance the squeezing simultaneously by using an apodized grating, as long as the solitons evolve adiabatically. The authors would like to use this paper to express their deep thanks and respect to Professor Hermann A Haus for the inspiration they have directly or indirectly received from him.

Lee, Ray-Kuang; Lai, Yinchieh

2004-08-01

398

Understanding incomplete scrambling in fibres: experimental investigations  

NASA Astrophysics Data System (ADS)

Recent advances in detection and characterization of exo-planets have led to increasing standards for repeatability of spectral-line detection of novel high-resolution spectrographs. This is important for exo-planet research but also has its impact on astroseismology and the study of variable stars. For these purposes optical fibres bear a huge advantage due to their improved scrambling ability - but this is subject to fundamental limits. This investigation gives experimental support for the theoretical proposals made in a companion paper which uses a ray-tracing approach. We will concentrate on the mechanisms that cause incomplete scrambling in order to gain insight in the true nature of scrambling, unlike previous mainly phenomenological studies. We describe the experimental setup that will be used to determine the fibre response to input beam parameters like focal ratio, tilt and offset. Preliminary experimental results are consistent with the theoretical predictions made and thus motivating a further exploration of these phenomena.

Lemke, U.; Allington-Smith, J. R.; Stürmer, J.

2012-09-01

399

An introduction to the short-term toxicology of respirable industrial fibres  

Microsoft Academic Search

Fibrous materials, exemplified by asbestos, that release respirable fibres are in common use and there is considerable knowledge regarding the toxicology of these common fibres. Newer materials or those that are under development, such as synthetic organic fibres and carbon nanotubes may have a different toxicology paradigms.The existing paradigm for silicate fibres suggests that respirable fibre types vary in their

Ken Donaldson; C. Lang Tran

2004-01-01

400

Stress Distribution and Effective Longitudinal Young's Modulus of Unidirectional Discontinuous Fibre Composites  

Microsoft Academic Search

In this article, stress and strain distributions in the elementary cell are studied in the case of unidirectional discontinuous fibre composites as functions of the geometrical arrangement of fibres. This arrangement is characterized by the volume frac tion of fibres, the fibre aspect ratio and the fibre spacing parameter. Thus, two extreme schemes are analyzed by the finite element method:

J.-M. Berthelot; A. Cupcic; K. A. Brou

1993-01-01

401

Effect of surface modification by bromination and metalation on Kevlar fibre-epoxy adhesion  

Microsoft Academic Search

This research uses metalation, bromination, and grafting to modify the surface of Kevlar fibre. The resulting fibre was characterized with tensile measurement, infrared spectroscopy, intrinsic viscosity, and scanning electron microscopy (SEM). From the SEM micrographs, the surface morphology of the bromine etched Kevlar fibre has a rougher surface than the untreated fibre. Furthermore, the tensile strength of Kevlar fibre decreases

Jeng-Shyong Lin

2002-01-01

402

On the frequency of occurrence of a peculiar polyester fibre type found in blue denim textiles  

Microsoft Academic Search

In a double murder investigation, the victims were found after a prolonged stay in a drainage canal. In spite of the expectations, fibre examination established a multitude of primary and secondary transferred fibres. One of these fibre types was a colourless polyester fibre possessing a blue coloured molten fibre end. These matched one of the types present in the suspect's

Kris De Wael; Christiaan Baes; Laurent Lepot; Fabrice Gason

403

Detecting the Progression of Eye Disease: CUSUM Charts for Assessing the Visual Field and Retinal Nerve Fiber Layer Thickness  

PubMed Central

Purpose The cumulative sum (CUSUM) is proposed and tested in a group of glaucoma patients and healthy subjects as a method for monitoring disease progression and for identifying clinically significant step changes in visual structure or function. Methods The CUSUM procedure is the recommended method for the timely detection of small step changes in manufacturing process control. The CUSUM procedure is discussed and compared with traditional approaches for the detection of change in the status of the visual system over time. The CUSUM approach is used to monitor over time visual field (VF) mean deviations and optical coherence tomography (OCT) measurements of retinal nerve fiber layer (RNFL) thickness in 53 healthy subjects and 103 patients with glaucoma. Results The CUSUM method detects VF progression for 35 of the 103 glaucoma patients (34.0%), and OCT RNFL reductions for 20 of the 103 glaucoma patients (19.4%). Conclusions The CUSUM method is effective in detecting small level changes. This method can be used to monitor the progression of disease and it benefits the clinician who must decide, on the basis of a time series of variable data, whether a change has occurred. Translational Relevance A cumulative sum chart helps the clinician decide whether a step change has taken place, and it does so as quickly as possible. This approach is particularly effective for detecting small step changes, which very likely are unnoticed with currently used change detection approaches.

Ledolter, Johannes; Kardon, Randy

2013-01-01

404

Cogeneration alternatives for Keyes Fibre Company  

Microsoft Academic Search

Cogeneration alternatives for Keyes Fibre Company paper mill are assessed. Four coal-fired cogeneration systems and one thermal-energy-only plant are conceptually designed and evaluated with respect to the existing oil-fired, noncogenerating system. Cogeneration with a backpressure turbine, as well as the thermal-only plant, appears to be a feasible alternative to the existing plant. The back-pressure turbine system may become economically more

C. Lee; A. Davis

1980-01-01

405

Dispersion-free fibre Bragg gratings  

Microsoft Academic Search

Fibre Bragg gratings with reduced\\/eliminated in-band dispersion are presented. When tested in add-drop configurations at 10 Gbit\\/s both 25 GHz and 50 GHz bandwidth gratings are shown to exhibit superior performance with no dispersion-induced penalties in the stopband. Furthermore, the demonstrated linear-phase Bragg gratings have >70% channel filling factor values and reflectivities in excess of 99.9%.

Morten Ibsen; Periklis Petropoulos; M. N. Zervas; Ricardo Feced

2001-01-01

406

Effective Properties of Viscoelastic Fibre Composites  

NASA Astrophysics Data System (ADS)

The present paper provides details on the application of asymptotic homogenization techniques for calculation of effective properties of fibre composite material. Correspondence principle allows transforming governing boundary value problems to the quasistatic ones. For solving of the cell problem modified boundary shape perturbation procedure is used. For inversion of the Laplace transform effective and accurate Gaver algorithm is used. Proposed approach gives the computer time consuming solution.

Andrianov, Igor V.; Danishevs'kyy, Vladyslav V.; Kirichek, Oleksandr U.

2010-09-01

407

Elastic fibres in patients with systemic sclerosis  

Microsoft Academic Search

Summary Dermal elastic fibres in biopsies taken from sun-exposed involved digital skin and sun-protected uninvolved skin on the medial aspect of the upper arms from 13 patients with systemic sclerosis were examined by light and transmission electron microscopy. For controls, biopsies were taken from similar sites from 4 age- and sex-matched healthy volunteers and 4 patients with primary Raynaud's phenomenon.

M. H. A. Rustin; Lucienne Papadaki; J. Rode; Pauline M. Dowd

1989-01-01

408

High Extinction Ratio In-Fibre Polarisers by Exploiting Tilted Fibre Bragg Grating Structures for Single-Polarisation High-Power Fibre Lasers and Amplifiers.  

National Technical Information Service (NTIS)

This report results from a contract tasking Aston University as follows: This is a follow-on proposal to our previous project of High extinction ratio in-fibre polarisers by exploiting tilted fibre Bragg grating structures for single-polarisation high-pow...

L. Zhang

2009-01-01

409

Finite-element analysis of the effect of material properties and fibre shape on stresses in an elastic fibre embedded in an elastic matrix in a fibre-composite material  

Microsoft Academic Search

The finite-element method was used to calculate the axial stress in an elastic fibre embedded in an elastic matrix to model a fibre-composite material. Axisymmet- ric models were created for cylindrical, ellipsoidal, paraboloidal and conical fibres embedded in a matrix and characterized by a fibre axial ratio, q. The effects of vary- ing q, from 200 to 1000, and the

R. M. A spden; K. J. Mathias; D. W. L. Hukins

2004-01-01

410

Towards woven logic from organic electronic fibres  

NASA Astrophysics Data System (ADS)

The use of organic polymers for electronic functions is mainly motivated by the low-end applications, where low cost rather than advanced performance is a driving force. Materials and processing methods must allow for cheap production. Printing of electronics using inkjets or classical printing methods has considerable potential to deliver this. Another technology that has been around for millennia is weaving using fibres. Integration of electronic functions within fabrics, with production methods fully compatible with textiles, is therefore of current interest, to enhance performance and extend functions of textiles. Standard polymer field-effect transistors require well defined insulator thickness and high voltage, so they have limited suitability for electronic textiles. Here we report a novel approach through the construction of wire electrochemical transistor (WECT) devices, and show that textile monofilaments with 10-100?m diameters can be coated with continuous thin films of the conducting polythiophene poly(3,4-ethylenedioxythiophene), and used to create micro-scale WECTs on single fibres. We also demonstrate inverters and multiplexers for digital logic. This opens an avenue for three-dimensional polymer micro-electronics, where large-scale circuits can be designed and integrated directly into the three-dimensional structure of woven fibres.

Hamedi, Mahiar; Forchheimer, Robert; Inganäs, Olle

2007-05-01

411

Photonic sensor of liquids based on suspended-core fibres  

NASA Astrophysics Data System (ADS)

The small size of the core (about 1 ?m) of the suspended-core optical fibres gives rise to evanescent wave in the surrounding channels. That process allows efficient coupling between light and liquid introduced into the channels and application of the fibre for analytic purposes. In the presented work, the channels of a suspended-core fibre were filled with water and aqueous solutions of oxazine 725 perchlorate and their absorption spectra were measured. While the spectra of the water-filled fibre were consistent with the Lambert-Beer law, the absorptivity of the fibre filled with oxazine 725 perchlorate solution demonstrated an increased sensitivity caused by aggregation of the oxazine molecules, independent on the fibre length.

Wajnchold, Barbara; Grabka, Michal; Pustelny, Szymon; Gawlik, Wojciech; Mergo, Pawel

2012-05-01

412

Bismuth-doped Mg - Al silicate glasses and fibres  

SciTech Connect

This paper compares the optical properties of bulk bismuth-doped Mg - Al silicate glasses prepared in an iridium crucible to those of optical fibres prepared by the powder-in-tube method and having a core identical in composition to the glasses. The bulk glasses and fibres are shown to be similar in luminescence properties. The optical loss in the fibres in their IR luminescence band is about one order of magnitude lower than that in the crucible-melted glasses. The level of losses in the fibres and their luminescence properties suggest that such fibres can be made to lase near 1.15 {mu}m. (optical fibres, lasers and amplifiers. properties and applications)

Bufetov, Igor' A; Vel'miskin, V V; Galagan, B I; Denker, B I; Sverchkov, S E; Semjonov, S L; Firstov, Sergei V; Shulman, I L; Dianov, Evgenii M

2012-09-30

413

A fibre optic oxygen sensor for monitoring of human breathing  

NASA Astrophysics Data System (ADS)

A reliable and cost effective fibre optic oxygen sensor for monitoring of human breathing has been developed using a normal 200?m silica core/silica cladding optical fibre and a polymer sensing matrix. The fibre optic oxygen sensor is based on the fluorescence quenching of a fluorophore by oxygen. The sensing matrix, containing immobilized Pt(II) complexes, was coated at the end of the silica core/silica cladding optical fibre. The sensitivity and time response of the sensor were evaluated using the method of luminescence lifetime measurement. The polymer substrate influence on the time response of the sensor was improved by using a fibre taper design, and the response time of the optimized sensor was less than 200ms. This silica fibre based optic oxygen sensor is suitable for monitoring of patient breathing in intensive care unit in terms of safety and low cost.

Chen, Rongsheng; Farmery, Andrew D.; Chen, Rui; Hahn, Clive E. W.

2011-11-01

414

Amplifying properties of heavily erbium-doped active fibres  

SciTech Connect

The relative concentration of erbium ions undergoing nonradiative relaxation from the metastable to the ground level is measured in aluminosilicate glass fibres doped with erbium ions at concentration between 3x10{sup 18} and 10{sup 20} cm{sup -3}. The dependence of the fraction of such ions on the Er{sup 3+} concentration is determined for fibres containing different amounts of aluminium oxide in a core. It is shown that the fraction of erbium ions not involved in amplification substantially decreases with increasing the Al{sub 2}O{sub 3} concentration. It is found that clustering leads to a considerable decrease in the gain in heavily Er{sup 3+}-doped active fibres. The dependence of the quantum efficiency of a fibre amplifier on the erbium ion concentration is obtained based on the measurements performed. This dependence can be used for optimising the parameters of erbium-doped fibre amplifiers. (fibres. integrated-optic waveguides)

Plotskii, A Yu; Kurkov, Andrei S; Yashkov, M Yu; Bubnov, M M; Likhachev, M E; Sysolyatin, A A; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Gur'yanov, A N [Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

2005-06-30

415

Transformation of optical vortices in elliptical and anisotropic optical fibres  

NASA Astrophysics Data System (ADS)

We study theoretically the process of conversion of the topological charge of optical vortices upon their propagation in anisotropic and elliptical weakly guiding optical fibres. We demonstrate that in addition to the well-known mechanism of topological charge conversion due to the elliptical form of the fibre's cross-section such a conversion can also be caused by the spin-orbit interaction. We show that in strongly anisotropic fibres, in which the other mechanism is prohibited, this interaction leads to charge conversion of both linearly and circularly polarized optical vortices. We also apply our theory to the description of experiments on mode conversion in fibres (McGloin et al 1998 Appl. Opt. 37 469, Carpentier et al 2006 J. Eur. Opt. Soc. Rap. Publ. 1 06031) and demonstrate that at the initial stage of fibre stressing the most probable reason of mode conversion is stress-induced photoelastic anisotropy of the fibre's core.

Alexeyev, C. N.; Volyar, A. V.; Yavorsky, M. A.

2007-04-01

416

Sugar palm (Arenga pinnata): Its fibres, polymers and composites.  

PubMed

Sugar palm (Arenga pinnata) is a multipurpose palm species from which a variety of foods and beverages, timber commodities, biofibres, biopolymers and biocomposites can be produced. Recently, it is being used as a source of renewable energy in the form of bio-ethanol via fermentation process of the sugar palm sap. Although numerous products can be produced from sugar palm, three products that are most prominent are palm sugar, fruits and fibres. This paper focuses mainly on the significance of fibres as they are highly durable, resistant to sea water and because they are available naturally in the form of woven fibre they are easy to process. Besides the recent advances in the research of sugar palm fibres and their composites, this paper also addresses the development of new biodegradable polymer derived from sugar palm starch, and presents reviews on fibre surface treatment, product development, and challenges and efforts on properties enhancement of sugar palm fibre composites. PMID:23121967

Ishak, M R; Sapuan, S M; Leman, Z; Rahman, M Z A; Anwar, U M K; Siregar, J P

2012-08-03

417

Fibre optic radiation sensor systems for particle accelerators  

Microsoft Academic Search

Two different fibre optic dosimeter systems based on the radiation-induced increase of fibre attenuation are presented. The systems allow on-line measurement of the accumulated dose along accelerator beam lines (“distributed” sensor) as well as at fixed positions in selected accelerator sections (local sensors). Fibre properties, system layout and results of measurements obtained during operation of the TESLA11Tera Electron Volt Energy

H. Henschel; M. Körfer; J. Kuhnhenn; U. Weinand; F. Wulf

2004-01-01

418

Fibre optic radiation sensor systems for particle accelerators  

NASA Astrophysics Data System (ADS)

Two different fibre optic dosimeter systems based on the radiation-induced increase of fibre attenuation are presented. The systems allow on-line measurement of the accumulated dose along accelerator beam lines (``distributed'' sensor) as well as at fixed positions in selected accelerator sections (local sensors). Fibre properties, system layout and results of measurements obtained during operation of the TESLA Test Facility (TTF) at DESY Hamburg are described. Tera Electron Volt Energy Superconducting Linear Accelerator.

Henschel, H.; Körfer, M.; Kuhnhenn, J.; Weinand, U.; Wulf, F.

2004-07-01

419

Temperature dependence of the stress response of fibre Bragg gratings  

Microsoft Academic Search

Fibre Bragg gratings, used as stress sensing elements, show a temperature dependence of their stress response, which is mainly characterized by Young's modulus of the fibre material. The temperature dependence of the stress response of a fibre Bragg grating over a range from -38 degreesC to +110 degreesC has been measured. The stress sensitivity decreases linearly by 1.22 x 10(-4)

Robert R J Maier; William N MacPherson; James S Barton; Julian D C Jones; Scott McCulloch; Gary Burnell

2004-01-01

420

Histological assessment of sintered metal-fibre-web materials.  

PubMed

Recently it has been shown that flexible metal fibre mesh structures can be used for the subcutaneous stabilisation of percutaneous devices. However, for the safe application of fibre mesh structures, it is necessary that these materials possess certain biological properties. The purpose of this paper is to discuss surgical, statistical and histological methods for the testing and evaluation of metal fibre web materials for soft tissue application. The use and potential of the described techniques are demonstrated with two examples. PMID:7983585

Jansen, J A; van't Hof, M A

1994-07-01

421

Myosin heavy chain isoform distribution in single fibres of bodybuilders  

Microsoft Academic Search

The purpose of this study was to investigate the long-term effects of high intensity resistance training on myosin heavy chain\\u000a (MHC) isoform composition of single fibres. Muscle biopsies were obtained from the right vastus lateralis of eight bodybuilders\\u000a (BB) and seven physical education students (PES). Histochemical analyses were used to determine the fibre type distribution\\u000a and the fibre cross-sectional area.

Nikolaos Kesidis; Thomas I. Metaxas; Ioannis S. Vrabas; Panagiotis Stefanidis; Efstratios Vamvakoudis; Kosmas Christoulas; Athanasios Mandroukas; Dimitrios Balasas; Konstantinos Mandroukas

2008-01-01

422

Functionalization, compatibilization and properties of polypropylene composites with Hemp fibres  

Microsoft Academic Search

Composites of isotactic polypropylene (PP) with Hemp fibres (Cannabis sativa), functionalized by means of melt grafting reactions with glycidyl methacrylate (GMA) and prepared by batch mixing, were examined. Either the modification of fibres (Hemp-GMA) and polyolefin matrix (PP-g-GMA), as well as the addition of various compatibilizers (PP-g-GMA, SEBS, SEBS-g-GMA) were carried out to improve the fibre–matrix interactions. The modified components

Mariano Pracella; Donatella Chionna; Irene Anguillesi; Zbigniew Kulinski; Ewa Piorkowska

2006-01-01

423

Alternatives to the Macintosh and flexible fibre-optic laryngoscopes  

Microsoft Academic Search

The Macintosh laryngoscope is very successful but there are several alternative methods of tracheal intubation. Many of these depend on advances in fibre-optic technology, which allow better visualization of the glottis when line of sight tactics are impossible. The flexible fibre-optic laryngoscope is the best known device, but a new generation of rigid and malleable fibre-optic endoscopes is appearing; they

Ian Calder

2005-01-01

424

Polyester moulding compounds of natural fibres and wollastonite  

Microsoft Academic Search

Combination of natural fibres and wollastonite whiskers has been attempted as an alternative to glass fibre reinforcement in polyester dough moulding compounds. Natural fibres (sisal) and wollastonite were surface-modified with polyester compatible neo pentyl (diallyl) oxy, tri (dioctyl) pyro-phosphato titanate and gamma-methacryloxy propyl trimethoxy silane coupling agents, respectively. Reinforcing effect of wollastonite to a level of ?50wt% in an unsaturated

B Singh; M Gupta; Anchal Verma

2003-01-01

425

Low frequency noise distributed-feedback ytterbium fibre laser  

SciTech Connect

We report a single-frequency 1-W fibre laser source emitting at 1093 nm, composed of a distributed-feedback ytterbium fibre laser and fibre-optic amplifier. The laser frequency was stabilised by side-locking to a transmission peak of a Fabry - Perot interferometer, and the residual frequency noise spectrum of the laser was measured. Our results indicate that the laser linewidth can be narrowed down below 1 kHz. (lasers)

Nikulin, M A; Babin, S A; Kablukov, S I [Novosibirsk State University, Novosibirsk (Russian Federation); Dmitriev, Aleksandr K; Dychkov, Aleksandr S; Lugovoy, Aleksei A [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Pecherskii, Yu Ya [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

2009-10-31

426

Mechanism of draw resonance in chemical fibre spinning  

Microsoft Academic Search

It was shown on the example of spinning fibres from solutions of poly-(p-phenylene terephthalamide) that periodic partial\\u000a breaking of the spun jets is a resonance phenomenon in spinneret drawing. The model of a fibre spun in the resonance mode\\u000a is considered to consist of two truncated cones and a cylinder. The first cone in the path of the fibre reflects

A. T. Serkov; M. B. Radishevskii; Yu. V. Afanas'eva

2000-01-01

427

Predicting the elastic modulus of natural fibre reinforced thermoplastics  

Microsoft Academic Search

Natural fibre reinforced thermoplastics (NFRT) are increasingly used in a variety of commercial applications, but there has been little theoretical modeling of structure\\/property relationships in these materials. In this study, micromechanical models available in the short fibre composites literature were used to predict the stiffness of some commercially important natural fibre composite formulations.Also included are equations that correct the Young’s

Angelo G. Facca; Mark T. Kortschot; Ning Yan

2006-01-01

428

Performance of natural fibre reinforced mortar roofing tiles  

Microsoft Academic Search

Interest in natural fibres as reinforcement in developing countries arose (when the use of steel and glass fibres in the industrialized\\u000a countries was being researched and developed in the late 1960s) mostly because of their lower cost and better availability\\u000a in the developing world. The use of natural fibres as reinforcement for mortar to be used mainly for roofing has

Zawde Berhane

1994-01-01

429

Fibre optic sensors with nano-structured coatings  

Microsoft Academic Search

A review of optical fibre devices employing nano-structured coatings is presented. Active and passive coatings, deposited using the Langmuir–Blodgett and electro-static self-assembly techniques, have been utilised to influence the transmission spectrum of optical fibres, with the aim of developing sensor elements and in-line components for telecommunications systems. Coupled waveguide, fibre grating and miniature Fabry–Perot cavities are described.

Stephen W. James; Ralph P. Tatam

2006-01-01

430

Squeezing flow of continuous fibre-reinforced composites  

Microsoft Academic Search

An experiment is presented in which a model fibre-reinforced composite undergoes squeeze-flow. Results are presented for two different fibre lay-ups over a range of fibre volume fractions. The response of the material is an initial rapid compression followed by a limiting deformation and a key feature of the experimental tests is their reproducibility. The experimental results show poor agreement with

J. A. Goshawk; V. P. Navez; R. S. Jones

1997-01-01

431

Development and Testing of Bamboo-Fibres Reinforced Plastic Composites  

Microsoft Academic Search

Many researchers in the past have developed composites with natural fibres such as of sisal, henequen, jute and palm; but the work on the bamboo-fibre reinforced com posites is not available in the literature published so far.In the present work, an effort has been made to develop bamboo-fibre reinforced plastic (BFRP) composites using a simple casting technique. These composites have

U. C. Jindal

1986-01-01

432

High birefringence fibre interrogating interferometer for optical sensing applications  

Microsoft Academic Search

We describe the use of high birefringence fibre forming a differential path interferometer for heterodyne fibre optic sensing applications. We firstly recover a low frequency strain amplitude of 1mu? at 1Hz applied to a fibre Bragg grating sensor demonstrating a noise limited resolution of around 100n?\\/&surd;Hz. Secondly we interrogate a Mach-Zehnder interferometer sensor using the dual wavelength technique to detect

D. C. C. Norman; Y. Lai; D. J. Webb

2005-01-01

433

Mechanical and structural characterization of the Nicalon silicon carbide fibre  

Microsoft Academic Search

The Nicalon SiC fibre offers the possibility of the development of composite materials for use above 1000 C. This study has\\u000a compared two types of Nicalon fibre, one which was shown to be amorphous and the other microcrystalline with a SiC grain radius\\u000a of 1.7 nm. Both fibres behaved in a brittle manner when tested in air and in argon

G. Simon; A. R. Bunsell

1984-01-01

434

The thermal expansion of carbon-fibre reinforced plastics  

Microsoft Academic Search

The thermal expansion characteristics of a series of carbon-fibre fabric reinforced plastic laminates over the approximate temperature range 90 K to 440 K have been determined. The reinforcements included Morganite Type II fibres in a plain weave and a two-by-two twill weave and Courtaulds Grafil E\\/XAS fibres in a two-by-two twill weave, a five-shaft satin weave and in an unwoven

K. F. Rogers; D. M. Kingston-Lee; L. N. Phillips; B. Yates; M. Chandra; S. F. H. Parker

1981-01-01

435

Stick-slip during fibre pull-out  

SciTech Connect

It has long been recognized that the mechanics associated with interfacial sliding and debonding is of paramount importance in determining the toughness of fibre-reinforced brittle-matrix composites. As a crack advances through such a composite it will be straddled by fibres. If the fibres are fairly ductible then a number of energy-absorbing mechanisms may be important: debonding and sliding of the interface, and deformation and possible failure of the fibres. In a composite reinforced with brittle fibres only the energy lose when the debonded fibres slide against the matrix can have any significant influence on the toughness. The mechanics of delamination and pull-out can most easily be studied by investigating a model system consisting of a single fibre embedded in a matrix. Although both the initial delamination process and the stick-slip behaviour associated with fibre pull-out have been frequently noted before they have not been investigated in detail. Recent advances in the data collection capabilities of testing machines have now made it possible to explore the details associated with both these processes. This paper present some initial findings of the phenomena that occur during fibre pull-out.

Cook, R.F.; Thouless, M.C.; Clarke, D.R.; Kroll, M.C. (IBM Research Div., Yorktown Heights, NY (USA))

1989-10-01

436

Design and Construction Elements for Scintillating Fibre Tracking Detectors  

NASA Astrophysics Data System (ADS)

In many nuclear and particle physics experiments, it is necessary to ascertain precise information about a particle's trajectory, or its position at specific locations (as a means for then determining angle or momentum). A common way to determine this information is by using a scintillating fibre tracker, a device that relies on scintillation light from ionizing charged particles (such as electrons or protons) within scintillating fibres, and guiding the produced scintillation light through standard fibre optics to determine which scintillating fibre detected the particle. This thesis discusses, and presents results for technical issues associated with designing and constructing such a detector: (1) adjacent scintillating fibre-to-fibre cross-talk, and (2) the effect on light transmission of the combination of different fibre-end finishes and clear-to-scintillating fibre optical couplants. These results will be directly incorporated into the construction of a scintillating fibre coordinate detector to be built for future experiments at Jefferson Lab's Hall A in Newport News, VA, USA.

Sharpe, Jason Ray

437

Analysis of collagen fibre shape changes in breast cancer  

NASA Astrophysics Data System (ADS)

Second harmonic generation microscopy was performed on both normal and diseased breast tissue. Differences in the collagen fibre shape between normal, benign and malignant breast tissue were compared and quantified using elliptical Fourier analysis. Principal shape analysis of these coefficients provided an understanding of the key differences in collagen fibre shape between the three tissue types. A Gaussian model was also used to associate the shape of the fibre with the probability that it had been sampled from malignant breast tissue. These results provide quantitative evidence for the alteration of collagen fibre shape in both benign and malignant breast tissue.

Falzon, G.; Pearson, S.; Murison, R.

2008-12-01

438

Analysis of collagen fibre shape changes in breast cancer.  

PubMed

Second harmonic generation microscopy was performed on both normal and diseased breast tissue. Differences in the collagen fibre shape between normal, benign and malignant breast tissue were compared and quantified using elliptical Fourier analysis. Principal shape analysis of these coefficients provided an understanding of the key differences in collagen fibre shape between the three tissue types. A Gaussian model was also used to associate the shape of the fibre with the probability that it had been sampled from malignant breast tissue. These results provide quantitative evidence for the alteration of collagen fibre shape in both benign and malignant breast tissue. PMID:18997272

Falzon, G; Pearson, S; Murison, R

2008-11-07

439

Electron Beam-Induced Graft Copolymerization of Vinyl Monomers on to Polyester Fibre.  

National Technical Information Service (NTIS)

Electron beam-induced graft copolymerization of acrylic acid on to multifilament PET fibre was carried out by simultaneous method. The fibre was impregnated with acrylic acid at room temperature and the impregnated fibre was irradiated with electron beams...

Hussin Mohamad Nor

1986-01-01

440

UV transparent and tuneable on-fibre polymeric phase masks for fibre and planar waveguide Bragg grating fabrication  

Microsoft Academic Search

UV transparent coatings have been used on optical fibres for direct writing of Bragg gratings without stripping-off the coating. In this paper we demonstrate a phase-mask as part of the coating of an optical fibre. We have fabricated these UV transparent, polymer phase-masks by moulding them on a holographic glass phase-mask in contact with optical fibres. These translation insensitive phase-masks

Jerome Poulin; Raman Kashyap

2005-01-01

441

An interrogator for fibre Bragg grating sensors using an ultrasonically induced long-period optical fibre grating  

Microsoft Academic Search

An ultrasonically induced long-period fibre grating (U-LPFG) functions as a tunable notch filter, since the pitch of refractive index modulation is changed by the driving frequency of the ultrasonic vibration propagating along a fibre. In this paper, we present the application of the U-LPFG for a fibre Bragg grating (FBG) sensor interrogator. If the U-LPFG is connected to the FBG

Norimichi Fukuma; Kenji Kubota; Kentaro Nakamura; Sadayuki Ueha

2006-01-01

442

Determination of fibre-matrix interfacial properties in ceramic-matrix composites by a fibre push-out technique  

Microsoft Academic Search

A simple concentric cylinder model is developed for the fibre push-out test in order to interpret the experimentally observed indenter load-displacement curves in ceramic-matrix composites. The fibre-matrix interface is assumed to be partially bonded and partially frictionally coupled. It is shown that a slope change in the loading curve corresponds to bonding at the fibre-matrix interface. In contrast an insignificant

R. N. Singh; M. Sutcu

1991-01-01

443

Influence of carbon fibre content on the processing and tribological properties of silicon nitride\\/carbon fibre composites  

Microsoft Academic Search

Si3N4\\/carbon fibre composites have been fabricated, and the effect of fibre content on the tribological properties was investigated under dry sliding conditions. The friction coefficient of the composites was around 30% of that of a monolithic Si3N4 composite. A fibre content of 5 vol.% was sufficient to maintain a graphite interface during the sliding tests, such that the friction coefficient

Hideki Hyuga; Mark I. Jones; Kiyoshi Hirao; Yukihiko Yamauchi

2004-01-01

444

Damage detection in glass fibre-reinforced plastic composites using self-sensing E-glass fibres  

NASA Astrophysics Data System (ADS)

The detection of damage in fibre-reinforced composite materials is important in areas where these materials are used for load-bearing applications. This paper reports on the use of conventional reinforcing E-glass fibres that were made to act as light guides. These reinforcing fibre light guides were used to detect damage induced in the composite by impact, indentation and flexure. The E-glass fibres were converted into light guides by applying an appropriate cladding material. The coating resins used in this study were an epoxy- and a polyurethane-based resin system. These self-sensing fibres or reinforcing fibre light guides were surface mounted and also embedded at two specified locations within 16-ply glass fibre-reinforced epoxy prepreg composites. The data generated in this study demonstrated that the self-sensing concept could be used to study in situ and in real time the failure processes in glass fibre-reinforced composites. A detailed study was also undertaken to characterize the various failure modes observed when the composites with the self-sensing light guides were subjected to impact, indentation and flexural loading. The damaged areas in the composite were easily located by means of the 'bleeding' light emanating from the broken self-sensing E-glass fibres.

Kister, Guillaume; Ralph, Brian; Fernando, Gerard F.

2004-10-01

445

Variability of muscle fibre composition and fibre size in the horse gluteus medius: an enzyme-histochemical and morphometric study.  

PubMed Central

To determine the variability in fibre types and fibre sizes in the equine gluteus medius muscle, biopsy specimens were removed from 5 sites, at 4 different depths, within the right and left muscles of 3 Andalusian stallions. The percentage, lesser fibre diameter and cross-sectional area of the various fibre types were measured systematically in myosin ATPase and NADH-tetrazolium reductase-stained, serial cryostat sections of these multiple samples. Significant differences in muscle fibre type composition were recorded, with a lower percentage of type I fibres (high myosin ATPase activity at pH 4.5) being observed towards superficial regions of the muscle and a greater percentage towards the deep areas. Type II B fibres (moderate myosin ATPase activity at pH 4.5), including both II B nonoxidative (low NADH-TR activity) and II B oxidative (moderate NADH-TR activity), displayed the opposite tendency, and the percentage of type II A fibres (low myosin ATPase activity at pH 4.5) did not change with depth. Types I and II A fibres in the deep regions were larger than superficially, whereas the II B fibres in the deep regions were smaller than in the superficial parts of the muscle. The results also imply that type I fibres tend to be larger than type II fibres in the deep regions. The size of type I fibres is more homogeneous in the deep parts than in the superficial regions of the muscle, while II B fibres vary more in size in the peripheral portions than in deep regions. A single biopsy taken from the gluteus medius muscle of the horse is therefore a poor representative of the whole muscle and care should be exercised in sampling and interpreting data obtained from limited biopsy of this muscle. The pattern of variation in fibre types and fibre sizes between the different depths of the muscle probably reflect different functional demands on the gluteus medius muscle. Images Fig. 1

Lopez-Rivero, J L; Serrano, A L; Diz, A M; Galisteo, A M

1992-01-01

446

Three myosin heavy chain isoforms in type 2 skeletal muscle fibres  

Microsoft Academic Search

Summary Mammalian skeletal muscles consist of three main fibre types, type 1, 2A and 2B fibres, with different myosin heavy chain (MHC) composition. We have now identified another fibre type, called type 2X fibre, characterized by a specific MHC isoform. Type 2X fibres, which are widely distributed in rat skeletal muscles, can be distinguished from 2A and 2B fibres by

Stefano Schiaffino; Luisa Gorza; Saverio Sartore; Leopoldo Saggin; Simonetta Ausoni; Monica Vianello; Kristian Gundersen; Terje LØmo

1989-01-01

447

Sandwiched polymer fibre in fibrin matrices for the dictation of endothelial cells undergoing angiogenesis  

NASA Astrophysics Data System (ADS)

We present here a three-dimensional (3D) sandwich system made by poly(ethylene terephthalate) (PET) fibre and fibrin extracellular matrix (ECM) for endothelial cell dictation and angiogenesis guidance. In this three-dimensional system, Human Umbilical Vein Endothelial cells (HUVECs) were firstly cultured for 2 (two) days to cover the PET fibre before sandwiched in two layer fibrin gel containing HUVECs. After 4 (four) days of culture, cel-to-cel connection, tube-like structure and multi-cellular lumen formation were then assessed and validated. Phase contrast and fluorescence imaging using an inverted microscope were used to determine cell-to-cell and cell-ECM interactions. Laser scanning confocal microscopy and histological techniques were used to confirm the development of tube-like structure and multi-cellular lumen formation. This study shows that polymer fibres sandwiched in fibrin gel can be used to dictate endothelial cells undergoing angiogenesis with potential application in cancer and cardiovascular study and tissue engineering vascularisation.

Sukmana, I.; Djuansjah, J. R. P.

2013-04-01

448

Human cutaneous C fibres activated by cooling, heating and menthol  

PubMed Central

Differential A-fibre block of human peripheral nerves changes the sensation evoked by innocuous cooling (?24°C) of the skin from ‘cold’ to ‘hot’ or ‘burning’, and this has been attributed to activity in unidentified unmyelinated fibres that is normally masked or inhibited by activity in A? cold fibres. Application of the TRPM8 agonist menthol to the skin evokes ‘burning/stinging’ as well as ‘cold’, and the unpleasant sensations are also enhanced by A-fibre block. In this study we used microneurography to search for C fibres in human skin activated by cooling and menthol, which could be responsible for these phenomena. Afferent C fibres were classified by activity-dependent slowing as Type 1A (polymodal nociceptor), Type 1B (mechanically insensitive nociceptor) or Type 2 (cold sensitive), and their responses to heating and cooling ramps were measured before and after topical application of menthol preparations (2–50%). The only C fibres activated by menthol were the Type 2 fibres, which discharged vigorously with innocuous cooling and were strongly activated and sensitized to cooling by menthol. Unlike an A? cold fibre, they continued to discharge at skin temperatures down to 0°C, and most (13/15) were also activated by heating. We propose that the Type 2 C fibres, although resembling A? cold fibres in their responses to innocuous cooling and menthol, have a more complex sensory function, colouring with a ‘hot-burning’ quality the perceptions of low and high temperatures. Their bimodal thermoreceptive properties may help account for several puzzling psychophysical phenomena, such as ‘innocuous cold nociception’, ‘paradoxical heat’ and the thermal grill illusion, and also for some neuropathic pains.

Campero, M; Baumann, T K; Bostock, H; Ochoa, J L

2009-01-01

449

Relations between Leu(5)-enkephalin- (LENK) and VIP-immunoreactive nerve fibres during human drug-resistant colitis. A case study.  

PubMed

The double immunofluorescence technique was used to examine the distribution and interrelationship between LENK- and VIP-immunoreactive nerve fibres within the muscle layer and myenteric plexus of the large intestine in a young female patient (aged 17 years) suffering from colitis ulcerosa activa (CUA). As the CUA was found to be totally drug-resistant, a pancolotomy was performed by means of the Soave technique. Varicose nerve fibres, immunoreactive either to LENK or VIP, but not to both substances simultaneously, were found in all fragments of the bowel studied. A striking feature was their distribution pattern within the studied layers. In all cases LENK-IR fibres were closely accompanied by VIP-IR terminals. The density of the examined fibres depended on the bowel fragment studied, and was the greatest in the sigmoid colon, descending colon and rectum, while the lowest number was found in the caecum. The results of the present study may thus be indicative for the involvement of LENK- and VIPIR nerve fibres in the control of bowel functions during CUA, possibly on the basis of a "cross-talk" between terminals running in close vicinity to each other. PMID:14655154

Kami?ska, Barbara; Gonkowski, S?awomir; Korzon, Maria; Bossowska, Agnieszka; Landowski, Piotr; Majewski, Mariusz

2003-11-01