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1

Onset and Progression of Peripapillary Retinal Nerve Fiber Layer (RNFL) Retardance Changes Occur Earlier Than RNFL Thickness Changes in Experimental Glaucoma  

PubMed Central

Purpose. Longitudinal measurements of peripapillary RNFL thickness and retardance were compared in terms of time to reach onset of damage and time to reach a specific progression endpoint. Methods. A total of 41 rhesus macaques with unilateral experimental glaucoma (EG) each had three or more weekly baseline measurements in both eyes of peripapillary RNFL thickness (RNFLT) and retardance. Laser photocoagulation was then applied to the trabecular meshwork of one eye to induce chronic elevation of intraocular pressure and weekly imaging continued. Pairwise differences between baseline observations were sampled by bootstrapping to determine the 95% confidence limits of each measurement's repeatability. The first two sequential measurements below the lower confidence limit defined the endpoint for each parameter. Segmented linear and exponential decay functions were fit to each RNFL-versus-time series to determine the time to damage onset. Results. In all, 29 (71%) of the EG eyes reached endpoint by RNFL retardance and 25 (61%) reached endpoint by RNFLT. In total, 33 (80%) reached endpoint by at least one of the RNFL parameters and 21 (51%) reached endpoint by both RNFL parameters. Of the 33 EG eyes reaching any endpoint, a larger proportion reached endpoint first by retardance (n = 26, 79%) than did by RNFLT (n = 7, 21%; P = 0.002). Survival analysis indicated a shorter time to reach endpoint by retardance than by RNFLT (P < 0.001). Of the 21 EG eyes that reached endpoint by both measures, the median duration to endpoint was 120 days for retardance and 223 days for RNFLT (P = 0.003, Wilcoxon test). The time to onset was faster for retardance than that for RNFLT based on either segmented fits (by 31 days; P = 0.008, average R2 = 0.89) or exponential fits (by 102 days; P = 0.01, average R2 = 0.89). Conclusions. The onset of progressive loss of RNFL retardance occurs earlier than the onset of RNFL thinning. Endpoints of progressive loss from baseline also occurred more frequently and earlier for RNFL retardance as compared with RNFLT. PMID:23847322

Fortune, Brad; Burgoyne, Claude F.; Cull, Grant; Reynaud, Juan; Wang, Lin

2013-01-01

2

Comparison of RNFL thickness and RPE-normalized RNFL attenuation coefficient for glaucoma diagnosis  

NASA Astrophysics Data System (ADS)

Recently, a method to determine the retinal nerve fiber layer (RNFL) attenuation coefficient, based on normalization on the retinal pigment epithelium, was introduced. In contrast to conventional RNFL thickness measures, this novel measure represents a scattering property of the RNFL tissue. In this paper, we compare the RNFL thickness and the RNFL attenuation coefficient on 10 normal and 8 glaucomatous eyes by analyzing the correlation coefficient and the receiver operator curves (ROCs). The thickness and attenuation coefficient showed moderate correlation (r=0.82). Smaller correlation coefficients were found within normal (r=0.55) and glaucomatous (r=0.48) eyes. The full separation between normal and glaucomatous eyes based on the RNFL attenuation coefficient yielded an area under the ROC (AROC) of 1.0. The AROC for the RNFL thickness was 0.9875. No statistically significant difference between the two measures was found by comparing the AROC. RNFL attenuation coefficients may thus replace current RNFL thickness measurements or be combined with it to improve glaucoma diagnosis.

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

2013-03-01

3

An investigation of the retinal nerve fibre layer in progressive multiple sclerosis using optical coherence tomography.  

PubMed

Axonal loss is thought to be the predominant cause of disability in progressive multiple sclerosis (MS). The retinal nerve fibre layer (RNFL) is composed largely of unmyelinated axons of retinal ganglion cells, and is accessible to study with optical coherence tomography (OCT), giving a measure of axonal loss. OCT measures of the RNFL thickness (RNFLT) and macular volume were studied in 23 patients with primary progressive multiple sclerosis (primary progressive MS) (13 male; 10 female; mean age 52 years; median EDSS 6.0; mean disease duration 11 years), and 27 patients with secondary progressive multiple sclerosis (secondary progressive MS) (8 male; 19 female; mean age 50 years; median EDSS 6; mean disease duration 22 years). Of the patients with secondary progressive MS, 14 had clinical history of optic neuritis (ON) in a single eye; the remaining patients had not had ON. Twenty healthy controls (11 male; 9 female; mean age 46 years) had RNFLT and macular volume studied. Of the patients' eyes not previously affected by ON, both the mean RNFL thickness and macular volume were reduced when compared with control values. The mean RNFL thickness and macular volume were significantly reduced in secondary progressive MS, but not in primary progressive MS when compared with control RNFL thickness and macular volume. RNFL loss was most evident in the temporal quadrant, where significant reduction was seen in primary progressive MS versus controls and in secondary versus primary progressive MS. There were significant correlations of decreased RNFLT and macular volume with measures of visual acuity, low contrast visual acuity and visual field mean deviation in the MS patients. There are significant global reductions in RNFLT and macular volume in the eyes of secondary progressive MS patients not previously affected by ON, but not in primary progressive MS patients, compared with controls. This may indicate a difference in the extent of the pathological processes that cause axonal loss in the retina, and by inference the optic nerve, in secondary progressive MS and primary progressive MS. PMID:18056739

Henderson, Andrew P D; Trip, S Anand; Schlottmann, Patricio G; Altmann, Daniel R; Garway-Heath, David F; Plant, Gordon T; Miller, David H

2008-01-01

4

Changes in retinal nerve fibre layer, optic nerve head morphology, and visual field after acute primary angle closure  

PubMed Central

Aims/Purpose To determine and correlate the long-term changes in retinal nerve fibre layer (RNFL) thickness, optic nerve head (ONH) morphology, and visual fields after a single episode of acute primary angle closure (APAC). Methods This was a cross-sectional comparative study of patients at National University Hospital (Singapore) from 2000 to 2006 after an episode of unilateral APAC. The peripapillary and macular RNFL were measured using Stratus optical coherence tomography (OCT) and ONH configuration was assessed using Heidelberg Retina Tomography (HRT)-III. Humphrey perimetry was also performed, and the presence of disc pallor was noted. APAC eyes were compared with fellow eyes as matched controls. Results Twenty-five patients were assessed at a median of 33 months (range, 11–85 months) after APAC. OCT showed that there was a reduction in the peripapillary and outer macular RNFL thickness in APAC eyes compared with controls. Humphrey perimetry revealed significantly reduced mean deviation (P=0.006) and increased pattern standard deviation (P=0.045) in APAC eyes compared with controls. HRT-III showed no difference in mean rim area, rim volume, or cup–disc ratio between APAC eyes and controls. Disc pallor was present in nine APAC eyes (36%) but was absent in fellow eyes (P=0.002), and was associated with peripapillary RNFL thinning, visual field loss, and an increased interval between the onset of symptoms and normalization of intraocular pressure (P=0.023). Conclusion APAC results in peripapillary and outer macular RNFL loss, visual field defects, and optic disc pallor, even in cases in which the ONH configuration remains unchanged. PMID:21436844

Sng, C C A; See, J S L; Ngo, C S; Singh, M; Chan, Y-H; Aquino, M C; Tan, A M; Shabana, N; Chew, P T K

2011-01-01

5

Influence of Anterior Segment Power on the Scan Path and RNFL Thickness Using SD-OCT  

PubMed Central

Purpose. Retinal nerve fiber layer (RNFL) thickness measures with spectral domain-optical coherence tomography (SD-OCT) provide important information on the health of the optic nerve. As with most retinal imaging technologies, ocular magnification characteristics of the eye must be considered for accurate analysis. While effects of axial length have been reported, the effects of anterior segment optical power on RNFL thickness measures have not been described fully to our knowledge. The purpose of our study was to determine the influence of the optical power change at the anterior corneal surface, using contact lenses, on the location of the scan path and measurements of RNFL thickness in normal healthy eyes. Methods. We recruited 15 normal subjects with less than 6 diopters (D) of ametropia and no ocular pathology. One eye of each subject was selected randomly for scanning. Baseline SD-OCT scans included raster cubes centered on the optic nerve and macula, and a standard 12-degree diameter RNFL scan. Standard 12-degree RNFL scans were repeated with 10 separate contact lenses, (Proclear daily, Omafilcon A/60%) ranging from +8 to ?12 D in 2-D steps. The extent of the retinal scan, and RNFL thickness and area measures were quantified using custom MATLAB programs that included ocular biometry measures (IOL Master). Results. RNFL thickness decreased (0.52 ?m/D, r = ?0.33, P < 0.01) and the retinal region scanned increased (0.52%/D, r = 0.97, P < 0.01) with increase in contact lens power (?12 to +8). The normalized/percentage rates of change of RNFL thickness (?0.11/mm, r = ?0.67, P < 0.01) and image size (0.11/mm, r = 0.96, P < 0.01) were related to axial length. Changes in the retinal region scanned were in agreement with transverse scaling, computed with a three surface schematic eye (R2 = 0.97, P < 0.01). RNFL area measures, that incorporated the computed transverse scaling, were not related significantly to contact lens power (863 ?m2/D, r = 0.06, P = 0.47). Conclusions. Measurements of RNFL thickness by SD-OCT are dependent on the optics of the eye, including anterior segment power and axial length. The relationships between RNFL thickness measures and optical power are a direct reflection of scan path location with respect to the optic nerve head rim, caused by relative magnification. An incorporation of transverse scaling to RNFL area measures, based on individualized ocular biometry, eliminated the magnification effect. PMID:22836769

Patel, Nimesh B.; Garcia, Brenda; Harwerth, Ronald S.

2012-01-01

6

Coconut fibre reinforced polyethylene composites: effect of natural waxy surface layer of the fibre on fibre\\/matrix interfacial bonding and strength of composites  

Microsoft Academic Search

Coconut fibre has been used as reinforcement in low-density polyethylene. The effect of natural waxy surface layer of the fibre on fibre\\/matrix interfacial bonding and composite properties has been studied by single fibre pullout test and evaluating the tensile properties of oriented discontinuous fibre composites. The waxy layer provided good fibre–matrix bond such that removal of the layer resulted in

M. Brahmakumar; C. Pavithran; R. M. Pillai

2005-01-01

7

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.

2012-03-01

8

Cellulose fibre networks reinforced with carboxymethyl cellulose/chitosan complex layer-by-layer.  

PubMed

An eco-friendly and full-polysaccharide polyelectrolyte complex system was developed to enhance the wet and dry tensile strength of cellulose fibre networks. Cellulose fibres were treated by carboxymethyl cellulose (CMC) in pulp suspension. Paper sheets made from CMC-treated fibres were further modified via the layer-by-layer (LbL) deposition of CMC/chitosan (CS) complex. The effect of number of CMC/CS layers on the strength properties of cellulose fibre networks (both under wet and dry conditions) was studied and sample structure was investigated by scanning electron microscopy (SEM). Water vapour transmission rate (WVTR) of CMC/CS-treated samples was also examined. The observed changes in the strength properties of treated samples were explained based on the competition between the rate of diffusion of CS to the fibre-fibre bond areas and the rate of disassociation of fibre-fibre interactions during the LbL deposition process. PMID:25263919

Wu, Tongfei; Farnood, Ramin

2014-12-19

9

Peripapillary retinal nerve fibre layer thickness measurement with SD-OCT in normal and glaucomatous eyes: distribution and correlation with age  

PubMed Central

AIM To determine peripapillary retinal fiber layer thickness (RNFL) measured with spectral domain optical coherence tomography (SD-OCT) in normal and glaucomatous eyes in a large sample of exclusively white population and compare results with other similarly constructed studies. METHODS Average, maximum, minimum and per quadrant RNFL thickness were measured in normal and glaucomatous Greek patients with a scanning laser ophthalmoscope (SLO)/SD-OCT device. The effect of age in normal RNFL thickness was also determined. RESULTS A total of 278 normal (278 patients) and 67 glaucomatous (67 patients) eyes were included in the study. Average RNFL thickness was 114.8±13.3µm in normal and 92.1±18.5µm in glaucomatous eyes (P<0.001). In normal discs, superior quadrant was the thickest, followed by the inferior, nasal and temporal. Decline of normal RNFL thickness with age was statistically significant for average RNFL thickness (1.92µm per decade of life) and for the superior and inferior quadrants of the disc. CONCLUSION SD-OCT peripapillary RNFL measurements can be used to distinguish between normal and glaucomatous eyes and establish normative databases, since normal disc measurements differ between different ethnic groups and between different SD-OCT devices. PMID:24195045

Kampougeris, George; Spyropoulos, Dimitrios; Mitropoulou, Adrianna; Zografou, Aggeliki; Kosmides, Pericles

2013-01-01

10

Birefringence and nerve fiber orientation in healthy in vivo primate RNFL with enhanced polarization-sensitive optical coherence tomography (EPS-OCT)  

Microsoft Academic Search

Form-birefringent properties of the retinal nerve fiber layer (RNFL) have become increasingly important as investigators strive to provide an improved methodology for glaucoma diagnosis. Techniques such as scanning laser polarimetry (SLP) and polarization-sensitive optical coherence tomography (PS-OCT) are two approaches which directly assess RNFL neurotubules, the sub-cellular structures responsible for form-birefringence and axoplasmic transport in retinal ganglion cell axons. We

Nate J. Kemp; Haitham N. Zaatari; Thomas E. Milner; H. G. Rylander III

2005-01-01

11

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

PubMed Central

Purpose To 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. Methods Sixty-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. Results RNFL 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. Conclusion RNFL 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

2013-01-01

12

Bruno Clair . Bernard Thibaut . Junji Sugiyama On the detachment of gelatinous layer in tension wood fibre  

E-print Network

wood fibre Accepted as original article in Journal of Wood Science (6th may 2004) Will be probably of longitudinal shrinkage in tension wood. The aim of this study was to observe the detachment of G-layer along fibres. Green wood block was cut transversely into two samples. One sample was kept in water

Paris-Sud XI, Université de

13

Fibre Optic Strain and Configuration Sensing in Engineering Components Produced by Additive Layer Rapid Manufacturing  

Microsoft Academic Search

Additive layered rapid manufacturing offers the ability to create physical parts with little or no restriction from shape complexity. Modelling and validation of this new technology requires embedded sensors which challenges conventional sensor technology. In this work, fibre Bragg gratings [FBG] have been embedded inside components made from a polymer during the manufacturing process of layer-by-layer additive manufacturing technology by

R. R. J. Maier; W. N. MacPherson; J. S. Barton; M. Carne; M. Swan; J. N. Sharma; S. K. Futter; D. A. Knox; B. J. S. Jones; S. McCulloch

2011-01-01

14

Detection of Retinal Nerve Fiber Layer Defects in Alzheimer's Disease Using SD-OCT  

PubMed Central

Introduction: Our aim is to examine the clinical value of spectral-domain optical coherence tomography (Spectralis OCT) to detect retinal nerve fibre layer defects in patients with clinically defined Alzheimer‘s disease (AD). Material and Methods: This cross-sectional study included 22 patients with AD (mean age: 75.9?±?6.1?years) and 22 healthy age- and sex-matched controls. Neuro-ophthalmologic examinations and a series of high-resolution OCT examinations of the peripapillary retinal nerve fiber layer (RNFL) thickness using the Spectralis 3.5-mm circle scan protocol with ART-Modus and eye tracking were obtained, and compared to age- and sex-matched healthy control subjects. Results: Patients with AD showed a significant decrease in RNFL thickness in the nasal superior sector compared to the control group (101.0?±?18.18??m versus 122.8?±?28.08??m; P?RNFL thickness compared to controls was detected. Using the advanced age- and gender-matched measurement model, 32 out of 42 eyes (76.19%) as pathologic with 67 abnormal sectors were detected. Discussion: As examined by spectral-domain OCT, patients with mild to moderate stages of AD showed a significant reduction of RNFL thickness in the nasal superior sector. Nevertheless, successive studies are needed. PMID:24616709

Kromer, Robert; Serbecic, Nermin; Hausner, Lucrezia; Froelich, Lutz; Aboul-Enein, Fahmy; Beutelspacher, Sven C.

2014-01-01

15

Shear properties of a carbon\\/carbon composite with non-woven felt and continuous fibre reinforcement layers  

Microsoft Academic Search

This study examines the shear properties of a 2D PAN-CVI carbon\\/carbon composite whose reinforcement layers are formed from a non-woven duplex cloth comprising a continuous fibre layer needled to a short fibre felt layer. Composites of three lay-ups were tested in several orientations using the Iosipescu (V-notched beam) shear test. Material anisotropy means that shear failure stresses and shear moduli

L. R. Bradley; C. R. Bowen; B. McEnaney; D. C. Johnson

2007-01-01

16

Exploring the room temperature self-assembly of silica nanoparticle layers on optical fibres  

NASA Astrophysics Data System (ADS)

The room temperature deposition of self-assembling silica nanoparticles onto D-shaped optical fibres ("D-fibre"), drawn from milled preforms fabricated by modified chemical vapor deposition, is studied and preliminary results reported here. Of various techniques explored, an automated "dip-and-withdraw" approach is found to give the most reproducible layers. Vertical dip-and-withdraw produces tapered layers with one end thicker (surface coverage < 0.85) than the other whilst horizontal dip-and-withdraw produces much more uniform layers over the core region. The problem of induced fracturing is shown to originate from the sides of the D-fibre flat, attributed to an extended, linear "coffee stain effect", and is greatest for horizontal dip-and-withdraw. Under optimal preparation conditions they can be minimised and prevented from extending over the core region. Alternatively, these structures can be made periodic potentially enabling some unique structures to be fabricated since post-deposition of functional species will be highest in these cracks.

Canning, John; Lindoy, Lachlan; Huyang, George; Naqshbandi, Masood; Cook, Kevin; Crossley, Maxwell J.; Luo, Yanhua; Peng, Gang-Ding; Glavind, Lars; Kristensen, Martin

2013-08-01

17

Optimized retinal nerve fiber layer segmentation based on optical reflectivity and birefringence for polarization-sensitive optical coherence tomography  

Microsoft Academic Search

Segmentation of the retinal nerve fiber layer (RNFL) from swept source polarization-sensitive optical coherence tomography (SS-PSOCT) images is required to determine RNFL thickness and calculate birefringence. Traditional RNFL segmentation methods based on image processing and boundary detection algorithms utilize only optical reflectivity contrast information, which is strongly affected by speckle noise. We present a novel approach to segment the retinal

Bingqing Wang; Amit S. Paranjape; Biwei Yin; Shuang Liu; Mia K. Markey; Thomas E. Milner; H. Grady Rylander III

2011-01-01

18

Xylan deposition and lignification in the multi-layered cell walls of phloem fibres in Mallotus japonicus (Euphorbiaceae).  

PubMed

Phloem fibres in Mallotus japonicus Müll. Arg. were found to have a multi-layered structure that is S1?+?S2?+?n(G?+?L), where a non-lignified gelatinous layer (G) and a lignified layer (L) are formed alternately and n indicates the number of repetitions of these two layers. The aim of this study was to determine the process of xylan deposition and lignification in the multi-layered cell walls of phloem fibres. The formation process of the multi-layered structure of secondary phloem fibres was examined by light microscopy, ultraviolet microscopy and transmission electron microscopy. The distribution of glucuronoxylan was examined by immunoelectron microscopy. The activity of peroxidase was also determined using metal-enhanced diaminobenzidine substrates. Immunolabelling of glucuronoxylan occurred in lignified cell wall layers, except in the compound middle lamella (CML), i.e., the S1, S2 and L layers but not the G layers. Change in immunolabelling density suggests that xylan deposition in these lignified layers occurs appositionally, i.e., xylan is deposited into the lignified layers directly and not by a penetrative mechanism, and deposition does not occur after the layers are fully deposited. Peroxidase activity was found in CML including cell corners during S2 layer formation, then in developing G layers during G layer formation. Peroxidase activity was also found in the thin L layers that formed recently and was not found in the L layers already present. Xylan labelling was not found in the thin L layers that formed recently but did occur in L layers that developed earlier. Lignification of the S1 and S2 layers continued during the formation of the G layers, whereas in the L layers it finished just after deposition of the L layer. PMID:25151648

Nakagawa, Kaori; Yoshinaga, Arata; Takabe, Keiji

2014-09-01

19

Selenium adsorption and speciation with Mg-FeCO? layered double hydroxides loaded cellulose fibre.  

PubMed

A novel adsorbent was developed by coating Mg-FeCO(3) layered double hydroxides (LDHs) on cellulose fibre. The LDHs take up significant amount of selenite and selenate in a wide pH range with similar sorption capacities (pH 3.8-8.0 for selenite and pH 5.8-7.0 for selenate). A mini-column packed with Mg-FeCO(3) LDHs layer coated cellulose fibre particles was incorporated into a sequential injection system for uptake of selenite at pH 6.0. The retained selenite was afterwards collected with 70 ? L of 0.8%(m/v) NaOH as eluent, followed by hydride generation and atomic fluorescence spectrometric detection. Total inorganic selenium was adsorbed at pH 6.0 by the LDHs-cellulose fibre mini-column after selenate was pre-reduced to selenite by 2.0 mol L(-1) HCl at 80°C, and selenium speciation was performed by difference. With a sample volume of 1.0 mL, an enrichment factor of 13.3 was derived with a detection limit of 11 ng L(-1) within a linear range of 0.04-4.0 ?g L(-1). A relative standard deviation (RSD) of 3.3% (0.5 ?g L(-1), n=11) was achieved. The procedure was validated by analyzing selenium in a certified reference material GBW 10010 (rice), and speciation of inorganic selenium in natural water samples. PMID:22748552

Chen, Ming-Li; An, Myog-Il

2012-06-15

20

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

21

Automatic quality enhancement and nerve fibre layer artefacts removal in retina fundus images by off axis imaging  

Microsoft Academic Search

Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Even with relative ease of use, the images produced sometimes suffer from reflectance artefacts mainly due to the nerve fibre layer (NFL) or camera lens related reflections. We propose a technique that employs multiple fundus images to obtain a single

Luca Giancardo; Fabrice Meriaudeau; T. P. Kamowski; Yaquin Li; Kenneth William Tobin Jr; Edward Chaum

2011-01-01

22

Polarization properties of the retinal nerve fiber layer investigated with multispectral imaging micropolarimetry  

NASA Astrophysics Data System (ADS)

Evaluation of the retinal nerve fiber layer (RNFL) is valuable in diagnosing glaucoma and other ocular neuropathic diseases. Several optical methods have been developed to assess the RNFL quantitatively. Knowledge about the optical properties of the RNFL and the underlying mechanisms is essential to understand these techniques and improve their assessment ability. Experimental studies show that the RNFL reflectance arises from the scattering of light by cylindrical structures. The measured reflectance spectra of the RNFL suggest that both thin and thick cylinders contribute to the RNFL reflection and experiments with colchicine suggest that microtubules are a likely candidate for the thin cylinders. The RNFL was modeled mathematically as an ensemble of uniformly distributed cylinders assumed to be form birefringent. The Mueller matrix of the RNFL model was derived and decomposed to reveal its polarization properties. The diattenuation of the model was due to the cylindrical scattering properties. The retardance exhibited in the model included the phase changes due to cylindrical scattering and to the RNFL birefringence. Reflection by the RNFL model preserved polarization. A multispectral imaging micropolarimeter was designed and calibrated. It was used to investigate the reflectance and polarization properties of the RNFL of isolated rat retinas. The RNFL retardance measured in transmission was constant over visible wavelengths, which suggested that only one mechanism was involved in the RNFL birefringence and agreed with the assumption of the RNFL being form birefringent. Measurements of diattenuation spectra of the RNFL reflectance revealed that intrinsic diattenuation is small at all wavelengths. The results led to two possible conclusions (1)if the RNFL reflection arises from scattering by spatially separated cylinders, the refractive index of these cylinders is close to that of the surrounding medium and (2)cylindrical structures other than spatially- separated cylinders may dominate the RNFL reflection; axonal membranes are a possible candidate. The reflected light from the RNFL preserved its polarization. Knowledge of the polarization properties of the RNFL reflectance could help to understand the measured signals in some optical techniques, such as optical coherence tomography (OCT) and scanning laser polarimetry (SLP), and therefore improve their assessment ability of the RNFL.

Huang, Xiangrun

23

Quality Enhancement and Nerve Fibre Layer Artefacts Removal in Retina Fundus Images by Off Axis Imaging  

SciTech Connect

Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relative low cost, these cameras are employed worldwide by retina specialists to diagnose diabetic retinopathy and other degenerative diseases. Even with relative ease of use, the images produced by these systems sometimes suffer from reflectance artefacts mainly due to the nerve fibre layer (NFL) or other camera lens related reflections. We propose a technique that employs multiple fundus images acquired from the same patient to obtain a single higher quality image without these reflectance artefacts. The removal of bright artefacts, and particularly of NFL reflectance, can have great benefits for the reduction of false positives in the detection of retinal lesions such as exudate, drusens and cotton wool spots by automatic systems or manual inspection. If enough redundant information is provided by the multiple images, this technique also compensates for a suboptimal illumination. The fundus images are acquired in straightforward but unorthodox manner, i.e. the stare point of the patient is changed between each shot but the camera is kept fixed. Between each shot, the apparent shape and position of all the retinal structures that do not exhibit isotropic reflectance (e.g. bright artefacts) change. This physical effect is exploited by our algorithm in order to extract the pixels belonging to the inner layers of the retina, hence obtaining a single artefacts-free image.

Giancardo, Luca [ORNL] [ORNL; Meriaudeau, Fabrice [ORNL] [ORNL; Karnowski, Thomas Paul [ORNL] [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL] [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK)

2011-01-01

24

Comparison of constitutive models of arterial layers with distributed collagen fibre orientations.  

PubMed

Several constitutive models have been proposed for description of mechanical behaviour of soft tissues containing collagen fibres. The model with aligned fibres is modified in this paper to take the dispersion of fibre orientations into account through angular integration and it is compared with the model that is defined through generalized structure tensor. The paper is focused on the effect of fibre dispersion on the resulting stress-strain behaviour predicted by both models analyzed. Analytical calculations are used for the comparison of the mechanical behaviour under a specific biaxial tension mode. The two models have been implemented into commercial finite element code ANSYS via user subroutines and used for numerical simulation resulting in a non-homogeneous stress field. The effects of the fibre dispersion predicted by both models being compared differ significantly, e.g., the resulting stress difference between both models is lower than 10% only in the case of extremely small dispersion of collagen fibres orientation (?< (0.01 to 0.03)). These results are consistent with those of other related literature. The applicability of the model defined through the generalized structure tensor is discussed. PMID:25308192

Skacel, Pavel; Bursa, Jiri

2014-01-01

25

Thickness and Birefringence of Healthy Retinal Nerve Fiber Layer Tissue Measured with Polarization-Sensitive Optical Coherence Tomography  

Microsoft Academic Search

PURPOSE. Thinning of the retinal nerve fiber layer and changes in retinal nerve fiber layer (RNFL) birefringence may both precede clinically detectable glaucomatous vision loss. Early detection of RNFL changes may enable treatment to prevent permanent loss of vision. Polarization-sensitive optical coher- ence tomography (PS-OCT) can provide objective information on RNFL thickness and birefringence. METHODS. PS-OCT scans around the optic

Barry Cense; Teresa C. Chen; B. Hyle Park; Mark C. Pierce; Johannes F. de Boer

2004-01-01

26

Numerical implementation of constitutive model for arterial layers with distributed collagen fibre orientations.  

PubMed

Several constitutive models have been proposed for the description of mechanical behaviour of soft tissues containing collagen fibres. Some of the commonly used approaches accounting for the dispersion of fibre orientations are based on the summation of (mechanical) contributions of differently oriented fibre families. This leads to the need of numerical integration on the sphere surface, and the related numerical consumption is the main disadvantage of this category of constitutive models. The paper is focused on the comparison of various numerical integration methods applied to a specific constitutive model applicable for arterial walls. Robustness and efficiency of several integration rules were tested with respect to application in finite element (FE) codes. Among all the analysed numerical integration rules, the best results were reached by Lebedev quadrature; the related parameters for the specific constitutive model are presented in the paper. The results were implemented into the commercial FE code ANSYS via user subroutines, and their applicability was demonstrated by an example of FE simulation with non-homogenous stress field. PMID:24168517

Skacel, Pavel; Bursa, Jiri

2015-06-01

27

Optimized retinal nerve fiber layer segmentation based on optical reflectivity and birefringence for polarization-sensitive optical coherence tomography  

NASA Astrophysics Data System (ADS)

Segmentation of the retinal nerve fiber layer (RNFL) from swept source polarization-sensitive optical coherence tomography (SS-PSOCT) images is required to determine RNFL thickness and calculate birefringence. Traditional RNFL segmentation methods based on image processing and boundary detection algorithms utilize only optical reflectivity contrast information, which is strongly affected by speckle noise. We present a novel approach to segment the retinal nerve fiber layer (RNFL) using SS-PSOCT images including both optical reflectivity and phase retardation information. The RNFL anterior boundary is detected based on optical reflectivity change due to refractive index difference between the vitreous and inner limiting membrane. The posterior boundary of the RNFL is a transition zone composed of birefringent axons extending from retinal ganglion cells and may be detected by a change in birefringence. A posterior boundary detection method is presented that segments the RNFL by minimizing the uncertainty of RNFL birefringence determined by a Levenberg-Marquardt nonlinear fitting algorithm. Clinical results from a healthy volunteer show that the proposed segmentation method estimates RNFL birefringence and phase retardation with lower uncertainty and higher continuity than traditional intensity-based approaches.

Wang, Bingqing; Paranjape, Amit S.; Yin, Biwei; Liu, Shuang; Markey, Mia K.; Milner, Thomas E.; Rylander, H. Grady, III

2011-09-01

28

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

29

Relationship Between Optic Nerve Appearance and Retinal Nerve Fiber Layer Thickness as Explored with Spectral Domain Optical Coherence Tomography  

PubMed Central

Purpose To study the relationship between the appearance of the optic nerve and the retinal nerve fiber layer (RNFL) thickness determined by spectral domain optical coherence tomography (OCT). Methods Records from patients with spectral domain-OCT imaging in a neuro-ophthalmology practice were reviewed. Eyes with glaucoma/glaucoma suspicion, macular/optic nerve edema, pseudophakia, and with refractive errors > 6D were excluded. Optic nerve appearance by slit lamp biomicroscopy was related to the RNFL thickness by spectral domain-OCT and to visual field results. Results Ninety-one patients (176 eyes; mean age: 49 ± 15 years) were included. Eighty-three eyes (47%) showed optic nerve pallor; 89 eyes (50.6%) showed RNFL thinning (sectoral or average peripapillary). Average peripapillary RNFL thickness in eyes with pallor (mean ± SD = 76 ± 17 ?m) was thinner compared to eyes without pallor (91 ± 14 ?m, P < 0.001). Optic nerve pallor predicted RNFL thinning with a sensitivity of 69% and a specificity of 75%. Optic nerve appearance predicted RNFL thinning (with a sensitivity and specificity of 81%) when RNFL had thinned by ? 40%. Most patients with pallor had RNFL thinning with (66%) or without (25%) visual field loss; the remainder had normal RNFL and fields (5%) or with visual field abnormalities (4%). Conclusions Optic nerve pallor as a predictor of RNFL thinning showed fair sensitivity and specificity, although it is optimally sensitive/specific only when substantial RNFL loss has occurred. Translational Relevance Finding an acceptable relationship between the optic nerve appearance by ophthalmoscopy and spectral domain-OCT RNFL measures will help the clinician's interpretation of the information provided by this technology, which is gaining momentum in neuro-ophthalmic research. PMID:25374773

Aleman, Tomas S.; Huang, Jiayan; Garrity, Sean T.; Carter, Stuart B.; Aleman, Wendy D.; Ying, Gui-shuang; Tamhankar, Madhura A.

2014-01-01

30

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

31

Thickness related textural properties of retinal nerve fiber layer in color fundus images.  

PubMed

Images of ocular fundus are routinely utilized in ophthalmology. Since an examination using fundus camera is relatively fast and cheap procedure, it can be used as a proper diagnostic tool for screening of retinal diseases such as the glaucoma. One of the glaucoma symptoms is progressive atrophy of the retinal nerve fiber layer (RNFL) resulting in variations of the RNFL thickness. Here, we introduce a novel approach to capture these variations using computer-aided analysis of the RNFL textural appearance in standard and easily available color fundus images. The proposed method uses the features based on Gaussian Markov random fields and local binary patterns, together with various regression models for prediction of the RNFL thickness. The approach allows description of the changes in RNFL texture, directly reflecting variations in the RNFL thickness. Evaluation of the method is carried out on 16 normal ("healthy") and 8 glaucomatous eyes. We achieved significant correlation (normals: ?=0.72±0.14; p?0.05, glaucomatous: ?=0.58±0.10; p?0.05) between values of the model predicted output and the RNFL thickness measured by optical coherence tomography, which is currently regarded as a standard glaucoma assessment device. The evaluation thus revealed good applicability of the proposed approach to measure possible RNFL thinning. PMID:24906911

Odstrcilik, Jan; Kolar, Radim; Tornow, Ralf-Peter; Jan, Jiri; Budai, Attila; Mayer, Markus; Vodakova, Martina; Laemmer, Robert; Lamos, Martin; Kuna, Zdenek; Gazarek, Jiri; Kubena, Tomas; Cernosek, Pavel; Ronzhina, Marina

2014-09-01

32

Retinal Nerve Fiber Layer Thickness in Women with Polycystic Ovary Syndrome  

PubMed Central

Aim. To compare the retinal nerve fiber layer (RNFL) thickness between women with polycystic ovary syndrome (PCOS) and healthy women. Materials and Methods. The study included 88 eyes of 44 women (group 1) with PCOS and 84 eyes of 42 healthy women (group 2). In all subjects, the RNFL and ganglion cell complex (GCC) thicknesses were measured by optical coherence tomography (OCT). In addition, visual acuity (VA), intraocular pressure (IOP), refractive errors, central macular thickness (CMT), central corneal thickness (CCT), and excavation of optic disc were evaluated in all subjects. Results. Mean values of GCC, IOP, VA, CMT, CCT, and refractive errors were similar between the 2 groups. The average RNFL, superior average RNFL, and inferior average RNFL thicknesses were higher in subjects with PCOS than in healthy subjects (P = 0.003, P = 0.012, and P = 0.009), respectively. Conclusion. The average RNFL, superior average RNFL, and inferior average RNFL thicknesses in women with PCOS were significantly higher than in healthy women. PMID:24377044

Demir, Mehmet; Guven, Dilek; Koc, Arzu; Ozdemir, Savas; Can, Efe

2013-01-01

33

Mucosal layers and related nerve fibres in non-chagasic and chagasic human colon-a quantitative immunohistochemical study.  

PubMed

Chagasic megacolon is accompanied by extensive myenteric and, simultaneously, moderate submucosal neuron loss. Here, we examined changes of the innervation pattern of the lamina propria (LP) and muscularis mucosae (MM). Two alternating sets of cryosections were taken from seven non-chagasic colonic and seven chagasic megacolonic specimens (the latter included both the dilated megacolonic and the non-dilated transitional oral and anal zones) and were immunohistochemically triple-stained for smooth-muscle actin (SMA), synaptophysin (SYN) and glial acid protein S100 and, alternatively, for SMA, vasoactive intestinal peptide (VIP) and somatostatin (SOM). Subsequent image analysis and statistical evaluation of nervous tissue profile areas revealed that, in LP, the most extreme differences (i.e. increase in thickness or decrease in nerve, glia and muscle tissue profile area, respectively) compared with control values occurred in the dilated megacolonic zone itself. In contrast, the most extreme differences in the MM were in the anal-to-megacolonic zone (except the profile area of muscle tissue, which was lowest in the megacolonic zone). This parallels our previous results in the external muscle coat. A partial and selective survival of VIP-immunoreactive in contrast to SOM-immunoreactive nerve fibres was observed in both mucosal layers investigated. Thus, VIPergic nerve elements might be crucial for the maintenance of the mucosal barrier. The differential changes of neural tissue parameters in LP and MM might reflect a multifactorial rather than a pure neurogenic development of megacolon in chronic Chagas' disease. PMID:24962547

Jabari, Samir; da Silveira, Alexandre B M; de Oliveira, Enio C; Quint, Karl; Wirries, André; Neuhuber, Winfried; Brehmer, Axel

2014-10-01

34

Depth and Area of Retinal Nerve Fiber Layer Damage and Visual Field Correlation Analysis  

PubMed Central

Purpose To evaluate the relationship between the structural damage as assessed by time-domain optical coherence tomography (OCT) and functional changes in glaucoma. Methods In total, 190 patients with normal tension glaucoma or primary open angle glaucoma were included in this study. The thickness of retinal nerve fiber layer (RNFL) around the optic disc and the area of RNFL defect were determined using OCT scans. The relationships between the RNFL thickness or area of the defect and visual field (VF) indices were assessed using the Lowess function, regression analysis and partial Spearman correlation. The differences between these associations depending on the stage of VF damage were further analyzed. Age, optic disc size, refraction, central corneal thickness and the presence of systemic disease were corrected for in order to exclude confounding factors. Results A logarithmic scale of RNFL thickness showed a negative linear relationship with VF indices. The area of the RNFL defect showed a weak correlation with the pattern of standard deviation, whereas the remnant RNFL thickness was moderately correlated with the pattern of standard deviation (partial Spearman correlation coefficient, 0.39, -0.47, respectively; p < 0.0001). Many outliers were detected in the Lowess-plotted graphs. Multiplication of the area and the inverted RNFL thickness showed a moderately correlated logarithmic relationship with the VF indices (partial Spearman correlation coefficient, 0.46; 95% confidence interval, 0.34 to 0.57; p < 0.0001). In the severe stage of VF damage, correlation between the area of the RNFL defect and mean deviation was significantly greater than in other stages (partial Spearman correlation coefficient, -0.66; p = 0.02). Conclusions The thickness of the RNFL had a negative logarithmic correlation with the VF indices and was more relevant to the VF indices than the area of the RNFL defect, as measured by OCT. PMID:25120341

Suh, Wool; Lee, Jung Min

2014-01-01

35

Effects of a high oil and fibre diet and supplementary roughage on performance, injurious pecking and foraging activities in two layer hybrids.  

PubMed

1. The study investigated the feeding of a high oil and fibre diet containing 260 g/kg organically produced cold pressed sunflower cake or supplemental roughage to aviary-housed Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) layers between 20 and 74 weeks of age with outdoor access during summer. 2. Feeding roughage was associated with reduced vent injuries, a tendency to improve plumage condition, and was accompanied by improved FCR compared with controls. Feeding the high oil and fibre diet tended to improve FCR compared with the control diet. 3. The dry matter of faeces was reduced in both treatments compared with controls. Foot pad cleanliness and the proportion of dirty eggs were negatively affected by the high oil and fibre diet. Foot health was superior in LB compared to LSL. 4. LB used the outdoor hen-runs more than LSL, but LSL consumed more litter indoors. Fewer LB hens fed on the control feed were recorded in the outdoor hen-runs. Supplemental roughage tended to decrease litter consumption. 5. In conclusion, supplemental roughage reduced vent injuries and was correlated with foraging activities. Feeding 260 g/kg sunflower cake negatively affected hygiene in aviary hens. Sunflower cake is nevertheless a promising alternative feedstuff to fulfil the protein requirement in organic layers. PMID:22646779

Kalmendal, R; Wall, H

2012-01-01

36

Dietary fibre.  

PubMed

Currently and after 30 years of research, dietary fibre is part of what is considered a healthy diet. There is no single definition yet comprising the different components of dietary fibre and its functions. The main factors of fibre are complex carbohydrates and lignin, although new products may be included in the future within the concept of fibre. Dietary fibres reach the large bowel and are attacked by colonic microflora, yielding short chain fatty acids, hydrogen, carbon dioxide, and methane as fermentation products. Short chain fatty acids represent a way of recovering energy and they are also implicated in other beneficial functions for the human organism. Although there are no yet conclusive data on recommendations of different types of fibre, it is still appropriate to indicate a diet providing 20-35 g/day of fibre from different sources. There is a consensus to recommend a mixture of fibres or fibre like soybean polysaccharide for constipation. There are few conclusive data, still, on the benefit of fibre on prevention of colorectal cancer and cardiovascular disease. However, a fibre-rich diet is recommended from early years of life since it is often associated to a lifestyle that in the long term helps controlling other risk factors. PMID:16771074

Escudero Alvarez, E; González Sánchez, P

2006-05-01

37

Physiological variation of retinal layer thickness is not caused by hydration: a randomised trial.  

PubMed

There is evidence for physiological variation of retinal thicknesses as determined by optical coherence tomography (OCT). We tested if such changes could be explained by hydration and would exceed what may be expected from normal ageing. Subjects (n=26) of a previous study were re-assessed and were randomised to 3 groups of a hydration escalation trial (no hydration, 1× hydration, 2× hydration). Automated retinal layer segmentations were performed for the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL). The averaged volumes were calculated for the central foveola, 3 mm and 6 mm circles of the ETDRS grid. Following oral hydration there were no significant differences of retinal layer thicknesses between the three randomised groups in any of the ETDRS regions at any time-point. Ageing related changes were significant over an 18 month period for the GCL. The negative outcome of this trial implies that, until the causes for the observed variation are resolved, investigators may need to accept, and include into trial power calculations, a small degree of variation (<1%) of quantitative SD-OCT imaging either due to human physiology or instrument/software related factors. PMID:25005893

Balk, Lisanne J; Oberwahrenbrock, Timm; Uitdehaag, Bernard M J; Petzold, Axel

2014-09-15

38

Estimated retinal ganglion cell counts in glaucomatous eyes with localized retinal nerve fiber layer defects  

PubMed Central

Purpose To estimate retinal ganglion cell (RGC) losses associated with visible glaucomatous localized retinal nerve fiber layer (RNFL) defects. Design Observational cross-sectional study. Methods A multicenter study of 198 normal eyes (138 subjects) and 66 glaucomatous eyes (55 subjects) recruited from the Diagnostic Innovations in Glaucoma Study and African Descent and Glaucoma Evaluation Study. All eyes had standard automated perimetry (SAP), spectral domain optical coherence tomography (SD-OCT) and fundus stereophotographs within 6 months. Glaucomatous eyes were included if localized RNFL defects were detected by masked grading of stereophotographs. The number of RGCs in each sector of a structure-function map was estimated using a previously published model combining RGC estimates from SAP and SD-OCT. The estimated percentage loss of RGCs (combined structure function index) was calculated. Results In glaucomatous eyes there were 136 sectors with visible RNFL defects and 524 sectors without visible RNFL defects. The commonest sectors with visible RNFL defects were inferior and inferotemporal sectors, followed by superior and superotemporal sectors. Eyes with visible RNFL defects had a mean estimated RGC count of 657,172 cells versus 968,883 cells in healthy eyes (P<0.001). The average combined structure function index in sectors with a visible RNFL defect (59±21%) was significantly higher than in sectors without a visible RNFL defect in glaucomatous eyes (15±29%, P<0.001) and higher than in healthy eyes (1±13%, P<0.001). Conclusions Although visible localized RNFL defects are often considered an early sign of glaucoma this study indicates that they are likely to be associated with large neuronal losses. PMID:23746612

Tatham, Andrew J.; Weinreb, Robert N.; Zangwill, Linda M.; Liebmann, Jeffrey M.; Girkin, Christopher A.; Medeiros, Felipe A.

2013-01-01

39

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. PMID:23826129

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

2013-01-01

40

15-March 2007 1 A Scintillating Fibre TrackerA Scintillating Fibre Tracker  

E-print Network

SFT 1SFT 1 SFT 2SFT 2 Weilin Yu, DPG Frühjahrstagung,Gie�en #12;15-March 2007 11 Scintillating Fibre Tracker(SFT) Built by JLU Giessen 2 cylinders of 2 X 2 layers, 100 stereo angle 1 mm Kuraray fibres Scintillating Fibre Tracker(SFT) Momentum measured in full azimuthal angle and reconstructed by bending 1 Tesla

41

Comparative Diagnostic Accuracy of Ganglion Cell-Inner Plexiform and Retinal Nerve Fiber Layer Thickness Measures by Cirrus and Spectralis Optical Coherence Tomography in Relapsing-Remitting Multiple Sclerosis  

PubMed Central

Objective. To estimate sensitivity and specificity of several optical coherence tomography (OCT) measurements for detecting retinal thickness changes in patients with relapsing-remitting multiple sclerosis (RRMS), such as macular ganglion cell-inner plexiform layer (GCIPL) thickness measured with Cirrus (OCT) and peripapillary retinal nerve fiber layer (pRNFL) thickness measured with Cirrus and Spectralis OCT. Methods. Seventy patients (140 eyes) with RRMS and seventy matched healthy subjects underwent pRNFL and GCIPL thickness analysis using Cirrus OCT and pRNFL using Spectralis OCT. A prospective, cross-sectional evaluation of sensitivities and specificities was performed using latent class analysis due to the absence of a gold standard. Results. GCIPL measures had higher sensitivity and specificity than temporal pRNFL measures obtained with both OCT devices. Average GCIPL thickness was significantly more sensitive than temporal pRNFL by Cirrus (96.34% versus 58.41%) and minimum GCIPL thickness was significantly more sensitive than temporal pRNFL by Spectralis (96.41% versus 69.69%). Generalised estimating equation analysis revealed that age (P = 0.030), optic neuritis antecedent (P = 0.001), and disease duration (P = 0.002) were significantly associated with abnormal results in average GCIPL thickness. Conclusion. Average and minimum GCIPL measurements had significantly better sensitivity to detect retinal thickness changes in RRMS than temporal pRNFL thickness measured by Cirrus and Spectralis OCT, respectively. PMID:25313352

Gonzalez-Lopez, Julio J.; Rebolleda, Gema; Leal, Marina; Oblanca, Noelia; Munoz-Negrete, Francisco J.; Costa-Frossard, Lucienne; Alvarez-Cermeno, Jose C.

2014-01-01

42

Retinal nerve fiber layer thickness in glaucomatous Nepalese eyes and its relation with visual field sensitivity  

PubMed Central

Background To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous Nepalese eyes using spectral domain optical coherence tomography (SD-OCT) and study its relationship with visual field sensitivity. Methods A total of 120 eyes comprising primary open angle glaucoma (POAG), glaucoma suspects (GS), normal tension glaucoma (NTG) and healthy subjects (n = 30 cases in each group) underwent a complete ophthalmic examination, including optic nerve head (ONH) evaluation and standard automated perimetry (SAP). RNFL thickness measurements around the optic disk were taken with circular spectral domain optical coherence tomography (SD-OCT) scans. Analysis of variance (ANOVA) was used for comparison of RNFL parameters among various study groups. The relationship of RNFL parameters with visual field (VF) global indices was evaluated with regression analysis. Results The mean pRNFL thickness was significantly less in the POAG (64.30 ± 14.45 ?m, p < 0.01), NTG (85.43 ± 9.79 ?m, p < 0.001) and GS (102.0 ± 9.37 ?m, p < 0.001) groups than in the healthy group (109.8 ± 8.32 ?m). The RNFL was significantly thinner across all quadrants in all study group pairs (p < 0.05) except for normal vs. GS (only superior and inferior quadrant, significant). Linear regression plots with RNFL thickness as a predictor of MD and LV demonstrated a strong and statistically significant degree of determination in the POAG group (R2 = 0.203 and 0.175, p = 0.013 and 0.021). Conclusion The RNFL thickness measurements with SD-OCT are lower in glaucomatous eyes as compared to age-matched GS and normal eyes in the Nepalese population. A high resolution SD-OCT could aid significantly in the early diagnosis of glaucoma in Nepal. PMID:25323643

Khanal, Safal; Thapa, Madhu; Racette, Lyne; Johnson, Richard; Davey, Pinakin Gunvant; Joshi, Mahesh Raj; Shrestha, Gauri Shankar

2014-01-01

43

Retinal Nerve Fiber Layer Atrophy Is Associated with Visual Field Loss over Time in Glaucoma Suspect and Glaucomatous Eyes  

PubMed Central

Purpose To prospectively compare detection of progressive retinal nerve fiber layer thickness (RNFL) atrophy identified using time-domain optical coherence tomography (OCT) with visual field progression using standard automated perimetry (SAP) in glaucoma suspect and preperimetric glaucoma and perimetric glaucoma patients. Design Prospective longitudinal clinical trial Methods Eligible eyes with ?2 years of follow-up underwent time-domain OCT and SAP every 6 months. The occurrence of visual field progression was defined as the first follow-up visit reaching a significant (p<0.05) negative visual field index (VFI) slope over time. RNFL progression/improvement was defined as a significant negative/positive slope over time. Specificity was defined as the number of eyes with neither progression nor improvement, divided by the number of eyes without progression. Cox proportional hazard ratios (HR) were calculated using univariate and multivariate models with RNFL loss as a time-dependent covariate. Results 310 glaucoma suspect and preperimetric glaucoma, and 177 perimetric glaucoma eyes were included. Eighty-nine eyes showed visual field progression and 101 eyes showed RNFL progression. The average time to detect visual field progression in those 89 eyes was 35±13 months; and to detect RNFL progression in those 101 eyes was 36±13 months. In multivariate Cox models, average and superior RNFL losses were associated with subsequent VFI loss in the entire cohort (every 10?m loss, HR=1.38,p=0.03; HR=1.20, p=0.01 respectively). Among the entire cohort of 487 eyes, 42 had significant VFI improvement and 55 had significant RNFL improvement (specificity 91.4% and 88.7%, respectively). Conclusion Structural progression is associated with functional progression in glaucoma suspect and glaucomatous eyes. Average and superior RNFL thickness may predict subsequent SAP loss. PMID:23036570

Sehi, Mitra; Zhang, Xinbo; Greenfield, David S.; Chung, YunSuk; Wollstein, Gadi; Francis, Brian A.; Schuman, Joel S.; Varma, Rohit; Huang, David

2012-01-01

44

Peripapillary Retinal Nerve Fiber Layer Assessment of Spectral Domain Optical Coherence Tomography and Scanning Laser Polarimetry to Diagnose Preperimetric Glaucoma  

PubMed Central

Purpose To compare the abilities of peripapillary retinal nerve fiber layer (RNFL) parameters of spectral domain optical coherence tomograph (SDOCT) and scanning laser polarimeter (GDx enhanced corneal compensation; ECC) in detecting preperimetric glaucoma. Methods In a cross-sectional study, 35 preperimetric glaucoma eyes (32 subjects) and 94 control eyes (74 subjects) underwent digital optic disc photography and RNFL imaging with SDOCT and GDx ECC. Ability of RNFL parameters of SDOCT and GDx ECC to discriminate preperimetric glaucoma eyes from control eyes was compared using area under receiver operating characteristic curves (AUC), sensitivities at fixed specificities and likelihood ratios (LR). Results AUC of the global average RNFL thickness of SDOCT (0.786) was significantly greater (p<0.001) than that of GDx ECC (0.627). Sensitivities at 95% specificity of the corresponding parameters were 20% and 8.6% respectively. AUCs of the inferior, superior and temporal quadrant RNFL thickness parameters of SDOCT were also significantly (p<0.05) greater than the respective RNFL parameters of GDx ECC. LRs of outside normal limits category of SDOCT parameters ranged between 3.3 and 4.0 while the same of GDx ECC parameters ranged between 1.2 and 2.1. LRs of within normal limits category of SDOCT parameters ranged between 0.4 and 0.7 while the same of GDx ECC parameters ranged between 0.7 and 1.0. Conclusions Abilities of the RNFL parameters of SDOCT and GDx ECC to diagnose preperimetric glaucoma were only moderate. Diagnostic abilities of the RNFL parameters of SDOCT were significantly better than that of GDx ECC in preperimetric glaucoma. PMID:25279801

Rao, Harsha L.; Yadav, Ravi K.; Addepalli, Uday K.; Chaudhary, Shashikant; Senthil, Sirisha; Choudhari, Nikhil S.; Garudadri, Chandra S.

2014-01-01

45

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. PMID:24092967

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

2013-01-01

46

Analysis of peripapilary retinal nerve fiber layer thickness of healthy Chinese from northwestern Shanghai using Cirrus HD-OCT  

PubMed Central

AIM To investigate peripapillary retinal nerve fiber layer (RNFL) thickness of healthy Chinese individuals from northwestern Shanghai using Cirrus HD-OCT (Carl Zeiss Meditec, Inc. Dublin, CA, USA). METHODS The peripapillary RNFL thickness of 720 eyes from 360 healthy Chinese participants were measured using the Optic Disc Cube 200×200 protocol. Each eye was scanned 3 times. Global and each quadrant's RNFL thickness around the optic nerve were compared between genders, and interocular differences were analyzed. The correlation between global RNFL thickness and age were also assessed in this study. RESULTS The mean global, superior, nasal, inferior and temporal RNFL thickness of all the eyes were 96.04±7.40 µm, 118.36±13.52 µm, 67.63±8.60 µm, 125.17±13.48 µm, 72.49±10.70 µm, respectively. When analyzing between genders, the mean nasal RNFL thickness of male and female were 68.29±8.44 µm and 66.97±8.70 µm, with statistically significant difference (P=0.038), while the data of global, superior, inferior and temporal quadrant showed no significant difference (all P>0.05). When analyzing interocular differences, the mean RNFL thickness of all the right eyes and all the left eyes were 116.46±13.17 µm and 120.27±13.61 µm in superior quadrant (P<0.001); 68.74±8.80 µm and 66.52±8.25 µm in nasal quadrant (P<0.001); 73.16±10.95 and 71.83±10.41 in temporal quadrant (P<0.001), all having statistically significant differences. There were no statistically significant interocular differences of global and inferior RNFL thickness (both P>0.05). There was a significantly negative correlation (r=-0.618, P<0.001) between the mean global RNFL thickness and the age. CONCLUSION In healthy Chinese from northwestern Shanghai, there were no significant differences detected interocular difference and between genders in the mean global RNFL thickness. Nevertheless, significant difference existed in the nasal quadrant between genders, and interocular differences existed in the superior, nasal and temporal quadrants. The RNFL thickness appeared to gradually decrease with age. PMID:25161937

Qu, Shen; Sun, Xiao-Ting; Xu, Wei; Rong, Ao

2014-01-01

47

Evaluation of retinal nerve fiber layer thickness in migraine  

PubMed Central

Background Headache is one of the most disturbing symptoms with common neurological signs. Variations in optic nerve perfusion quality or retinal microcirculation may end up in ganglion cell damage in patients with migraine. Methods Sixty patients diagnosed with migraine and thirty normal individuals were evaluated in groups including migraine with aura, migraine without aura and controls. Retinal nerve fiber layer (RNFL) thickness was measured using stratus optical coherence tomography (OCT™) and then was compared in case and control groups. Results RNFL thickness was only significantly thinner in nasal quadrant in migraineurs compared to the control group. Other parameters showed no difference between the two groups and besides there was no statistically difference between the two migraine subgroups. Conclusion Given the significant difference in nasal quadrant RNFL thickness between the migraineurs and normal individuals, we might be able to defend the retinal blood flow decrease theory in migraine; however, multicentre studies with larger samples seem mandatory. PMID:24250902

Sorkhabi, Rana; Mostafaei, Somaiyeh; Ahoor, Mohammadhosein

2013-01-01

48

Multimaterial Piezoelectric Fibres  

E-print Network

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 ...

Egusa, S.

49

Comparison of localized retinal nerve fiber layer defects in highly myopic, myopic, and non-myopic patients with normal-tension glaucoma: a retrospective cross-sectional study  

PubMed Central

Background The purpose of this study was to evaluate the relationship between patterns of localized retinal nerve fiber layer (RNFL) defects and the degree of myopia in patients with normal-tension glaucoma (NTG). Methods We retrospectively reviewed medical records of patients with high myopia (42 eyes; spherical equivalent [SE]?RNFL defects. On RNFL photographs, the proximity of the RNFL defect to the center of the fovea (angle I) and the sum of the angular width of the defects (angle II) were determined. The patterns of localized RNFL defects were then compared with respect to differences in angles I and II. Results Angle I was significantly smaller in the high myopia group than in the low to moderate myopia group (p?=?0.028) and the emmetropia group (p?=?0.044), while angle II was significantly larger in the high myopia group compared with the low to moderate myopia group and the emmetropia group (p?RNFL defects are wider and closer to the fovea in eyes with high myopia than those with low to moderate myopia or emmetropia. PMID:24188326

2013-01-01

50

A review of bast fibres and their composites. Part 1 – Fibres as reinforcements  

Microsoft Academic Search

Bast fibres are defined as those obtained from the outer cell layers of the stems of various plants. The fibres find use in textile applications and are increasingly being considered as reinforcements for polymer–matrix composites as they are perceived to be “sustainable”. The fibres are composed primarily of cellulose which potentially has a Young’s modulus of ?140GPa (being a value

John Summerscales; Nilmini P. J. Dissanayake; Amandeep S. Virk; Wayne Hall

2010-01-01

51

Degradation in the degree of polarization in human retinal nerve fiber layer.  

PubMed

Using a fiber-based swept-source (SS) polarization-sensitive optical coherence tomography (PS-OCT) system, we investigate the degree of polarization (DOP) of light backscattered from the retinal nerve fiber layer (RNFL) in normal human subjects. Algorithms for processing data were developed to analyze the deviation in phase retardation and intensity of backscattered light in directions parallel and perpendicular to the nerve fiber axis (fast and slow axes of RNFL). Considering superior, inferior, and nasal quadrants, we observe the strongest degradation in the DOP with increasing RNFL depth in the temporal quadrant. Retinal ganglion cell axons in normal human subjects are known to have the smallest diameter in the temporal quadrant, and the greater degradation observed in the DOP suggests that higher polarimetric noise may be associated with neural structure in the temporal RNFL. The association between depth degradation in the DOP and RNFL structural properties may broaden the utility of PS-OCT as a functional imaging technique. PMID:24390374

Yin, Biwei; Wang, Bingqing; Rylander, Henry G; Milner, Thomas E

2014-01-01

52

Optical coherence tomographic assessment of retinal nerve fiber layer thickness changes before and after glaucoma filtration surgery  

PubMed Central

Background: Glaucomatous Optic Neuropathy (GON) is very common in the glaucoma patients, and impaired effect of glaucoma is measured by the Retinal Nerve Fiber Layer (RNFL) thickness. Objective: The study was conducted to find out the mean RNFL thickness, RNFL thickness in different quadrants, Intra-Ocular Pressure (IOP) changes, and visual field changes after filtration surgery in different ages and genders using Optical Coherence Tomography (OCT). Materials and Methods: The study was an interventional case-series conducted at the Glaucoma Clinic at the Regional Institute of Ophthalmology at Kolkata from March 2009 to August 2010. Fifty-one eyes of 43 open angle glaucoma patients had been selected for clinical and ophthalmologic evaluation. All the eyes of glaucoma patients who fulfilled the inclusion criteria were registered in the study population. The glaucoma filtration surgery was done in these patients. The RNFL thickness, IOP, visual field changes were measured before and after intervention of filtration surgery. Pre-operative OCT images of RNFL were obtained 0 to 120 days before surgery, and post-operative images were obtained from 60 to 120 days after surgery. Data collected in a standard data collection form included schedule. Results: Paired t-test was used. RNFL thickness was (pre-operative: 52.56 ± 17.40, post-operative: 58.48 ± 20.20, P < 0.0001) significantly increased after filtration surgery measured by OCT with significant reduction of IOP (r = - 0.38, P = 0.005) irrespective of age and gender. Conclusions: An increase in RNFL thickness was observed after glaucoma filtration surgery that correlated with IOP reduction. PMID:24799793

Sarkar, Kumaresh Chandra; Das, Palash; Pal, Ranabir; Shaw, Chattaranjan

2014-01-01

53

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. PMID:19494208

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

2009-01-01

54

Peripapillary Nerve Fiber Layer Thickness Profile Determined with High Speed, Ultrahigh Resolution Optical Coherence Tomography High-Density Scanning  

PubMed Central

Purpose To determine the retinal nerve fiber layer (RNFL) thickness profile in the peripapillary region of healthy eyes. Methods Three-dimensional, Fourier/spectral domain optical coherence tomography (OCT) data were obtained as raster scan data (512 × 180 axial scans in a 6 × 6-mm region centered on the optic nerve head [ONH]) with high-speed, ultrahigh-resolution OCT (hsUHR-OCT) from 12 healthy subjects. RNFL thickness was measured on this three-dimensional data set with an in-house software program. The disc margin was defined subjectively in each image and RNFL thickness profiles relative to distance from the disc center were computed for quadrants and clock hours. A mixed-effects model was used to characterize the slope of the profiles. Results Thickness profiles in the superior, inferior, and temporal quadrants showed an initial increase in RNFL thickness, an area of peak thickness, and a linear decrease as radial distance from the disc center increased. The nasal quadrant showed a constant linear decay without the initial RNFL thickening. A mixed-effects model showed that the slopes of the inferior, superior, and nasal quadrants differed significantly from the temporal slope (P = 0.0012, P = 0.0003, and P = 0.0004, respectively). Conclusions RNFL thickness is generally inversely related to the distance from the ONH center in the peripapillary region of healthy subjects, as determined by hsUHR-OCT. However, several areas showed an initial increase in RNFL, followed by a peak and a gradual decrease. PMID:17591885

Gabriele, Michelle L.; Ishikawa, Hiroshi; Wollstein, Gadi; Bilonick, Richard A.; Kagemann, Larry; Wojtkowski, Maciej; Srinivasan, Vivek J.; Fujimoto, James G.; Duker, Jay S.; Schuman, Joel S.

2007-01-01

55

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. PMID:24109175

Zeried, Ferial M; Osuagwu, Uchechukwu L

2013-01-01

56

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

57

Patterns of Subsequent Progression of Localized Retinal Nerve Fiber Layer Defects on Red-free Fundus Photographs in Normal-tension Glaucoma  

PubMed Central

Purpose To investigate patterns of subsequent progression of localized retinal nerve fiber layer (RNFL) defects and to quantify the extent of progression in normal-tension glaucoma (NTG) patients. Methods Thirty-three eyes of 33 consecutive NTG patients who had shown continuous progression of localized RNFL defect on serial red-free fundus photographs were selected for the study. Patterns of subsequent progression of localized RNFL defects were categorized, and extents of progression were quantified. Serial evaluations of disc stereophotographs and visual fields were also performed to detect progression. Results The most common pattern was continuous widening of the defect towards the macula (n = 11, 33.3%) followed by sharpening of the defect border after widening of the defect towards the macula (n = 5, 15.2%), continuous widening of the defect away from the macula (n = 2, 6.1%), and deepening of the defect after appearance of a new defect (n = 2, 6.1%). Four eyes (12.1%) simultaneously showed two patterns of subsequent progression. In 13 eyes that showed continuous widening of the defect, subsequent angular widening towards the macula and away from the macula were 9.2 ± 6.0° (range, 1.1° to 24.4°; n = 11) and 5.2 ± 4.9° (range, 0.3° to 11.3°; n = 2), respectively. Thirty-two eyes showed no progression of optic disc cupping. Out of the 21 eyes in which Humphrey central 30-2 threshold visual field tests were performed after progression of RNFL defects, 15 eyes showed no deterioration in the visual field. Conclusions There were nine patterns of subsequent progression of localized RNFL defects. Among them, continuous RNFL loss proceeding temporally was the most common one. Initial progression of the defect proceeded temporally, especially in the defect located at the inferior fundus, might be at a risk of further RNFL loss temporally. PMID:25120342

Kim, Tai Jun; Kim, Young Kook

2014-01-01

58

Marketing goat fibres  

Microsoft Academic Search

Goat fibres that are produced, marketed and processed in commercial volumes are mohair and cashmere. These fibres constitute approximately 0.3% of all textile fibres. Mohair is produced in South Africa, Turkey, United States of America, Argentina, Australia, New Zealand and Lesotho. Production is dictated by price that is dependant on very fickle fashion trends. Over the past 15 years production

J. M. van der Westhuysen

2005-01-01

59

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

60

Blood Vessel Contributions to Retinal Nerve Fiber Layer Thickness Profiles Measured With Optical Coherence Tomography  

PubMed Central

Purpose To understand better the influence of retinal blood vessels (BVs) on the interindividual variation in the retinal nerve fiber layer (RNFL) thickness measured with optical coherence tomography (OCT). Subjects and Methods RNFL thickness profiles were measured by OCT in 16 control individuals and 16 patients. The patients had advanced glaucoma defined by abnormal disc appearance, abnormal visual fields, and a mean visual field deviation worse than ? 10 dB. Results In general, the OCT RNFL thickness profiles showed 4 local maxima, with the peak amplitudes in the superior and inferior regions occurring in the temporal (peripapillary) disc region. There was considerable variability among individuals in the location of these maxima. However, the 4 maxima typically fell on, or near, a major BV with the temporal and inferior peaks nearly always associated with the main temporal branches of the superior and inferior veins and arteries. In the patients’ hemifields with severe loss (mean visual field deviation worse than ? 20 dB), the signals associated with the major BVs were in the order of 100 to 150 µm. Conclusions The variation in the local peaks of the RNFL profiles of controls correlates well with the location of the main temporal branches of the superior and inferior veins and arteries. This correspondence is, in part, due to a direct BV contribution to the shape of the OCT RNFL and, in part, due to the fact that BVs develop along the densest regions of axons. Although the overall BV contribution was estimated to be relatively modest, roughly 13% of the total peripapillary RNFL thickness in controls, their contribution represents a substantial portion locally and increases in importance with disease progression. PMID:18854727

Hood, Donald C.; Fortune, Brad; Arthur, Stella N.; Xing, Danli; Salant, Jennifer A.; Ritch, Robert; Liebmann, Jeffrey M.

2010-01-01

61

Reproducibility of Peripapillary Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography in Pseudophakic Eyes  

PubMed Central

Purpose To assess the reproducibility of circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurement (measurement agreement) and its color-coded classification (classification agreement) by Cirrus spectral domain optical coherence tomography (OCT) in pseudophakic eyes. Methods Two-hundred five participants having glaucoma or glaucoma suspected eyes underwent two repeated Cirrus OCT scans to measure cpRNFL thickness (optic disc cube 200 × 200). After classifying participants into three different groups according to their lens status (clear media, cataract, and pseudophakic), values of intra-class coefficient (ICC), coefficient of variance, and test-retest variability were compared between groups for average retinal nerve fiber layer (RNFL) thicknesses and that corresponding to four quadrant maps. Linear weighted kappa coefficients were calculated as indicators of agreement of color code classification in each group. Results ICC values were all excellent (generally defined as 0.75 to 1.00) for the average and quadrant RNFL thicknesses in all three groups. ICC values of the clear media group tended to be higher than those in the cataract and pseudophakic groups for all quadrants and average thickness. Especially in the superior and nasal quadrants, the ICC value of the cataract group was significantly lower than that of the clear media and pseudophakic groups. For average RNFL thickness, classification agreement (kappa) in three groups did not show a statistically significant difference. For quadrant maps, classification agreement (kappa) in the clear media group was higher than those in the other two groups. Conclusions Agreement of cpRNFL measurement and its color code classification between two repeated Cirrus OCT scans in pseudophakic eyes was as good as that in eyes with clear crystalline lens. More studies are required to ascertain the effect of lens status on the reproducibility of Cirrus OCT according to different stages of glaucoma patients. PMID:24688256

Kim, Gyu Ah; Lee, Jun Mo; Park, Kyoung Soo

2014-01-01

62

Analytical modelling and numerical simulation of the nonlinear deformation of hybrid fibre metal laminates  

Microsoft Academic Search

GLARE laminates are an advanced hybrid material system consisting of alternating layers of thin aluminium sheets and unidirectional or biaxial reinforced high strength glass fibre\\/epoxy composite layers. The unique combination of ductile aluminium layers with high strength composite layers results in a unique fibre-metal laminate (FML) having light weight, outstanding fatigue resistance, excellent impact resistance, flame resistance and corrosion properties.

Guocai Wu; Jenn-Ming Yang

2005-01-01

63

Characterisation of Grass Fibres  

Microsoft Academic Search

The elementary grass fibres were isolated from different grass and legumes sorts, i.e. Ryegrass (Lolium hybridum Gumpenstein), Wheat straw, Trefoil (Trifolium pratense) and Lucerne (Medicago sativa). The fibre-samples were obtained in a bio-refinery, after the liquid phase containing proteins and lactic acid was eliminated from the ensiled and green grasses, respectively. For the isolation of elementary grass fibres different processes

M. Sfiligoj Smole; T. Kreze; S. Strnad; K. Stana Kleinschek; S. Hribernik

2005-01-01

64

Track reconstruction with a central two-shell scintillating fibre tracker (SFT)  

Microsoft Academic Search

We present a track reconstruction algorithm designed for the scintillating fibre tracker (SFT), having in view the upgrade of the L3 detector for LEP-II. This algorithm can also be applied for particle tracking at future hadron colliders. The tracking elements are polystyrene fibres of 60 mum diameter, which are arranged as fused coherent bundles into fibre layers. We study in

F. Anselmo; F. Block; Luisa Cifarelli; C. D'Ambrosio; Thierry Gys; G. La Commare; H. Leutz; M. Marino; S. Qian

1994-01-01

65

A review of bast fibres and their composites. Part 2 – Composites  

Microsoft Academic Search

Bast fibres are defined as those obtained from the outer cell layers of the stems of various plants. The fibres find use in textile applications and are increasingly being considered as reinforcements for polymer matrix composites as they are perceived to be “sustainable”. The fibres are composed primarily of cellulose which potentially has a Young’s modulus of ?140 GPa (being

John Summerscales; Nilmini Dissanayake; Amandeep Virk; Wayne Hall

2010-01-01

66

Determination of Axial Length Requiring Adjustment of Measured Circumpapillary Retinal Nerve Fiber Layer Thickness for Ocular Magnification  

PubMed Central

Purpose To determine the axial length requiring adjustment of measured circumpapillary retinal nerve fiber layer (cpRNFL) thickness to account for ocular magnification during spectral-domain optical coherence tomography (SD-OCT). Methods In this prospective study, 148 eyes of 148 healthy student volunteers were imaged by two examiners using three-dimensional SD-OCT. In 54 randomly selected eyes, total cpRNFL thickness was measured with and without adjustment for ocular magnification to establish intra-examiner and inter-examiner measurement error. The 148 eyes were then divided into three groups according to the error values: control group (difference in the corrected and uncorrected total cpRNFL thickness was within the measurement error range), thinner group (the corrected total cpRNFL thickness was less than the uncorrected one), and thicker group (the corrected total cpRNFL thickness was more than the uncorrected one). The cutoff values of axial length between the control and the other groups were calculated by receiver operating characteristic analysis. Results Measurement error ranged from 4.2 to 5.3 µm; the threshold value was defined as 5.3 µm. The cutoff values of axial length between the thinner and the control groups and between the control and the thicker groups were 23.60 (area under the curve [AUC]?=?0.959) and 25.55 (AUC?=?0.944) mm, respectively. Conclusions Axial lengths shorter than 23.60 mm and longer than 25.55 mm require adjustment of measured cpRNFL thickness to account for ocular magnification during SD-OCT. Clinical Trial Registration UMIN Clinical Trials Registry (http://www.umin.ac.jp/) under unique trial number UMIN000013248 (date of registration: 02/24/2014) PMID:25215521

Hirasawa, Kazunori; Shoji, Nobuyuki; Yoshii, Yukako; Haraguchi, Shota

2014-01-01

67

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. PMID:22427978

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

2012-01-01

68

Ganglion Cell Layer-Inner Plexiform Layer Thickness and Vision Loss in Young Children With Optic Pathway Gliomas  

PubMed Central

Purpose. To determine if measures of macular ganglion cell layer–inner plexiform layer (GCL-IPL) thickness can discriminate between children with and without vision loss (visual acuity or field) from their optic pathway glioma (OPG) using spectral-domain optical coherence tomography (SD-OCT). Methods. Children with OPGs (sporadic or secondary to neurofibromatosis type 1) enrolled in a prospective study of SD-OCT were included if they were cooperative for vision testing and macular SD-OCT images were acquired. Manual segmentation of the macular GCL-IPL and macular retinal nerve fiber layer (RNFL) was performed using elliptical annuli with diameters of 1.5, 3.0, and 4.5 mm. Logistic regression assessed the ability of GCL-IPL and RNFL thickness measures (micrometers) to differentiate between the normal and abnormal vision groups. Results. Forty-seven study eyes (normal vision = 31, abnormal vision = 16) from 26 children with OPGs were included. Median age was 5.3 years (range, 2.5–12.8). Thickness of all GCL-IPL and RNFL quadrants differed between the normal and abnormal vision groups (P < 0.01). All GCL-IPL measures demonstrated excellent discrimination between groups (area under the curve [AUC] > 0.90 for all diameters). Using the lower fifth percentile threshold, the number of abnormal GCL-IPL inner macula (3.0 mm) quadrants achieved the highest AUC (0.989) and was greater than the macula RNFL AUCs (P < 0.05). Conclusions. Decreased GCL-IPL thickness (layer–inner plexiform layer thickness could be used as a surrogate marker of vision in children with OPGs. PMID:24519429

Gu, Sherry; Glaug, Natalie; Cnaan, Avital; Packer, Roger J.; Avery, Robert A.

2014-01-01

69

Fluidic fibre dye lasers  

NASA Astrophysics Data System (ADS)

We report the demonstration of compact fluidic fibre lasers based on capillary tubes and photonic crystal fibres, featuring single channel and multiple laterally integrated fluidic lasers respectively. Their preparation was based on capillary action and lasing occurred without the need for external mirrors or lithographically defined microstructures. The fibre lasers were found to be tunable by varying the chromophore density in the liquid core and a functional wavelength selectivity mechanism inherent in both types of lasers provided a long free spectral range that does not correspond to the length of the fibres. The enhanced mode spacing is attributed to a Vernier resonant effect.

Vasdekis, A. E.; Town, G. E.; Turnbull, G. A.; Samuel, I. D. W.

2007-04-01

70

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

71

Myocardial fibre calcification  

Microsoft Academic Search

Three cases of myocardial fibre calcification found at post-mortem examination are described. In one case there was antemortem hypercalcaemia and hyperphosphataemia and the case was clearly an example of metastatic calcification. In the other two cases there was ischaemic myocardial necrosis and calcification was seen in fibres which were not overtly necrotic, but which were both in proximity to (the

J McClure; A S Pieterse; D J Pounder; P S Smith

1981-01-01

72

Agreement of Two Different Spectral Domain Optical Coherence Tomography Instruments for Retinal Nerve Fiber Layer Measurements  

PubMed Central

Purpose To determine the agreement between Spectralis and Cirrus spectral domain optical coherence tomography (SD-OCT) measurements of peripapillary retinal nerve fiber layer (RNFL) thickness. Methods Suspected or confirmed cases of glaucoma who met the inclusion criteria underwent peripapillary RNFL thickness measurement using both the Spectralis and Cirrus on the same day within a few minutes. Results Measurements were performed on 103 eyes of 103 patients with mean age of 50.4±17.7 years. Mean RNFL thickness was 89.22±15.87 versus 84.54±13.68 µm using Spectralis and Cirrus, respectively. The difference between measurements and the average of paired measurements with the two devices showed a significant linear relationship. Bland-Altman plots demonstrated that Spectralis thickness values were systematically larger than that of Cirrus. Conclusion Spectralis OCT generates higher peripapillary RNFL thickness readings as compared to Cirrus OCT; this should be kept in mind when values obtained with different instruments are compared during follow-up. PMID:24982729

Faghihi, Hooshang; Hajizadeh, Fedra; Hashemi, Hassan; Khabazkhoob, Mehdi

2014-01-01

73

Adjusted color probability codes for peripapillary retinal nerve fiber layer thickness in healthy Koreans  

PubMed Central

Background Though a newly developed spectral domain optical coherence tomography (OCT) is at the center of interests for many ophthalmologic researchers and clinicians, its own characteristics are not fully evaluated yet. The main purpose of this study was to establish the adjusted color probability codes for peripapillary retinal nerve fiber layer (RNFL) thickness in healthy Koreans and to compare them with original color codes provided by spectral domain OCT. Methods Two hundred ninety-five healthy Korean eyes were enrolled and their peripapillary RNFL thickness was measured by Cirrus OCT. For each decade of age, the normal thickness reference was determined on the basis of z-scores and the adjusted color probability codes were established. Then the agreements between adjusted and original color codes were calculated using weighted Kappa (Kw) coefficient. Results On the basis of Kw coefficient, the overall agreement between the adjusted and original probability color codes was not excellent (Kw range of 0.500 to 0.806). If the adjusted probability codes were assumed as a standard of comparison, the original color codes showed the false-negative in 11% of eyes and the false-positive in 0.3% of eyes for average RNFL thickness. Conclusions Adjusted color probability codes judged by the Korean normative data showed a discrepancy with original codes. It implies that normal reference and adjusted probability codes for each ethnicity might be needed to determine whether a certain RNFL thickness is within normal range or not. PMID:24678925

2014-01-01

74

On defining dietary fibre.  

PubMed

Establishing a definition for dietary fibre has historically been a balance between nutrition knowledge and analytical method capabilities. While the most widely accepted physiologically-based definitions have generally been accurate in defining the dietary fibre in foods, scientists and regulators have tended, in practice, to rely on analytical procedures as the definitional basis in fact. As a result, incongruities between theory and practice have resulted in confusion regarding the components that make up dietary fibre. In November 1998 the president of the American Association of Cereal Chemists (AACC) appointed an expert scientific review committee and charged it with the task of reviewing and, if necessary, updating the definition of dietary fibre. The committee was further charged with assessing the state of analytical methodology and making recommendations relevant to the updated definition. After due deliberation, an updated definition of dietary fibre was delivered to the AACC Board of Directors for consideration and adoption (Anon, 2000; Jones 2000b). The updated definition includes the same food components as the historical working definition used for approximately 30 years (a very important point, considering that the majority of the research of the past 30 years delineating the positive health effects of dietary fibre is based on that working definition). However, the updated definition more clearly delineates the make-up of dietary fibre and its physiological functionality. As a result, relatively few changes will be necessary in analytical methodology. Current methodologies, in particular AACC-approved method of analysis 32-05 (Grami, 2000), Association of Official Analytical Chemists' official method of analysis 985.29 (Horwitz, 2000a) or AACC 32-07 (Grami, 2000) Association of Official Analytical Chemists 991.43 (Horwitz, 2000a) will continue to be sufficient and used for most foods. A small number of additional methods will be necessary to quantify the dietary fibre levels in foods containing fibres such as fructans (polymers and oligomers of fructose, inulin), modified dextrins, and/or synthetic dietary fibre analogues. PMID:12740055

DeVries, Jonathan W

2003-02-01

75

Developmental Changes in Cell Wall Structure of Phloem Fibres of the Bamboo Dendrocalamus asper  

PubMed Central

• Background and aims Bamboo culms have excellent physical and mechanical properties, which mainly depend on their fibre content and anatomical structure. One of the features which is known to contribute to the high tensile strength in bamboo is the multilayered structure of the fibre cell wall. The aim of this study was to characterize the development of the layered structure in fibre cell walls of developing and maturing culms of Dendrocalamus asper. • Methods Cell wall development patterns were investigated in phloem fibre caps of vascular bundles in the inner culm wall areas of Dendrocalamus asper of three different age classes (<6 months old, 1 year old, 3 years old). A combination of light microscopy and image analysis techniques were employed to measure cell wall thickness and to determine number of cell wall layers, as well as to describe the layering structure of fibre walls. Two-dimensional maps showing the distribution pattern of fibres according to the number of cell wall layers were produced. • Key results The cell walls of fibres in phloem fibre caps located in the inner part of the culm wall of D. asper developed rapidly during the first year of growth. Six different fibre types could be distinguished based upon their cell wall layering and all were already present in the young, 1-year-old culm. In the mature stage (3 years of age) the multilayering was independent of the cell wall thickness and even the thinner-walled fibres could have a large number of wall layers. The multilayered nature of cell wall structure varied considerably between individual cells and was not exclusively related to the cell wall thickness. Nevertheless, fibres at the periphery of the fibre bundles and immediately adjacent to the phloem elements exhibited a consistent and high degree of layering in their cell walls. • Conclusions The multilayered structure of fibre cell walls was formed mainly during the first year of growth by the deposition of new wall layers of variable thickness, resulting in a high degree of heterogeneity in the layering patterns amongst individual fibres. A degree of ‘order’ in the distribution of multilayered fibres within the caps does exist, however, with multilayered cell walls common in fibres adjacent to phloem elements and around the edge of the fibre cap. These findings confirm the observations, primarily in Phyllostachys viridi-glaucescens. The layering structure was not found to be specifically related to the thickness of the cell wall. PMID:15319227

GRITSCH, CRISTINA SANCHIS; KLEIST, GUNNAR; MURPHY, RICHARD J.

2004-01-01

76

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. PMID:24098599

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

2013-01-01

77

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 5.6-15 ° 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 (A x, axon area less non-cytoskeletal organelle area) mode. A x represents a RGC axon's neurotubule-inhabitable area. Intuitively, a strong relationship should exist between A x 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 A x 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

78

Fireproof viscose fibres  

Microsoft Academic Search

A modifying bath composition was developed for manufacture of fireproof viscose fibres used for fabrication of textiles with\\u000a a fireproofing effect and resistant to laundering. The existence of a chemical reaction in the viscose fibre (VF)—Pyrofax\\u000a (PF) system was demonstrated and the mechanism of action of PF in thermoly sis and combustion was determined. Multicomponent\\u000a bath compositions were developed for

N. N. Krylova; L. G. Panova; S. E. Artemenko

1998-01-01

79

Visible light optical coherence tomography for in vivo imaging the spectral contrasts of the retinal nerve fiber layer  

NASA Astrophysics Data System (ADS)

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 contrasts for imaging the earliest damage to the RNFL. To image the spectral contrasts we built a dual-band spectral-domain optical coherence tomography (SD-OCT) with centered wavelength of 415nm (VIS) and 808nm (NIR), respectively. The light at the two bands was provided by the fundamental and frequency-doubled outputs of a broadband Ti: Sapphire laser. The depth resolutions of the VIS and NIR OCT systems are 12.2?m and 4.7?m in the air. The system was applied to imaging the rat retina in vivo. Significantly different appearances between the OCT cross sectional images at the two bands are observed. 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

2012-01-01

80

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

81

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

Microsoft Academic Search

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)

Andrei S Kurkov; V I Karpov; O I Medvedkov; Evgenii M Dianov; Sergei A Vasilev; Vladimir M Paramonov; V N Protopopov; A Yu Laptev; A N Guryanov; A A Umnikov; N I Vechkanov; V G Artyushenko; J Frahm

1999-01-01

82

Fibre swelling during laser drilling of carbon fibre composites  

Microsoft Academic Search

Fine holes have been laser-drilled in bundles of carbon fibres, using a pulsed Nd:YAG laser (?=1.06?m). Examination of the drilled fibres showed that some were significantly swollen, with diameter increases up to ?60%. Scanning electron microscopy (SEM) and Raman spectroscopy have been used to investigate the effects of fibre type on the extent of laser-induced fibre swelling. It has been

K. T. Voisey; S. Fouquet; D. Roy; T. W. Clyne

2006-01-01

83

Fibre system of DESI  

NASA Astrophysics Data System (ADS)

We describe the fiber system of the Dark Energy Spectroscopic Instrument (DESI). Its primary science goal is to provide a survey of 14,000 square degrees of the extragalactic sky using the Mayall 4m telescope in five years. The fibre system will provide a multiplex gain of 5000 so that more than 20 million galaxies can surveyed. Applying a number of tests to the survey dataset should allow the evolution of the equation of state of the universe to be determined to greater accuracy than before. The fibre system will provide a multiplex gain of 5000 with very high levels of performance.

Allington-Smith, Jeremy; Poppett, Claire; Bramall, David; Edelstein, Jerry; Lafever, Robin; Schmoll, Jürgen; Dunlop, Colin; Murray, Graham; Besuner, Robert; Talbot, Gordon

2014-07-01

84

Oxidative stabilization of acrylic fibres  

Microsoft Academic Search

When acrylic fibres are heat treated for various times at 220 to 250° C, they form dark, insoluble structures of uncertain chemical character which are inert to many strong oxidizing and reducing agents. The heat-treated fibres are, however, rapidly decoloured by warm alkaline hypochlorite solutions. When fibres which have undergone short-time heat treatment are subjected to the hypochlorite, incubation periods

S. S. Chen; J. Herms; L. H. Peebles; D. R. Uhlmann

1981-01-01

85

Dynamically reconfigurable fibre optical spanner.  

PubMed

In this paper we describe a pneumatically actuated fibre-optic spanner integrated into a microfluidic Lab-on-a-Chip device for the controlled trapping and rotation of living cells. The dynamic nature of the system allows interactive control over the rotation speed with the same optical power. The use of a multi-layer device makes it possible to rotate a cell both in the imaging plane and also in a perpendicular plane allowing tomographic imaging of the trapped living cell. The integrated device allows easy operation and by combining it with high-resolution confocal microscopy we show for the first time that the pattern of rotation can give information regarding the sub-cellular composition of a rotated cell. PMID:24493284

Kolb, Thorsten; Albert, Sahradha; Haug, Michael; Whyte, Graeme

2014-03-21

86

The Effect of Pattern Scan Laser Photocoagulation on Peripapillary Retinal Nerve Fiber Layer Thickness and Optic Nerve Morphology in Diabetic Retinopathy  

PubMed Central

Purpose To evaluate the effect of pattern scan laser (PASCAL) photocoagulation on peripapillary retinal nerve fiber layer (RNFL) thickness, central macular thickness (CMT), and optic nerve morphology in patients with diabetic retinopathy. Methods Subjects included 35 eyes for the PASCAL group and 49 eyes for a control group. Peripapillary RNFL thickness, cup-disc area ratio and CMT were measured before PASCAL photocoagulation and at 2 and 6 months after PASCAL photocoagulation in the PASCAL or control groups. Results The average RNFL thickness had increased by 0.84 µm two months after and decreased by 0.4 µm six months after PASCAL photocoagulation compared to baseline, but these changes were not significant (p = 0.83, 0.39). The cup-disc area ratio was unchanged after PASCAL photocoagulation. CMT increased by 18.11 µm (p = 0.048) at two months compared to baseline thickness, and partially recovered to 11.82 µm (p = 0.11) at six months in the PASCAL group. Conclusions PASCAL photocoagulation may not cause significant change in the peripapillary RNFL thickness, CMT, and optic nerve morphology in patients with diabetic retinopathy. PMID:25276083

Lee, Dong Eik; Lee, Ju Hyang; Lim, Han Woong; Kang, Min Ho; Cho, Hee Yoon

2014-01-01

87

Preformed activated carbon matting derived from the pyrolysis of biomass natural fibre textile waste  

Microsoft Academic Search

Low grade biomass fibre produced as a by-product from the flax and hemp industry was manufactured into a non-woven, pre-formed matting material via entanglement, layering and needling. The advantage of such a structure is that textile technology is used to form a self supporting fibre matrix, utilising the ease with which fibre can be worked. The non-woven matting was then

Paul T Williams; Anton R Reed

2003-01-01

88

Oxidation of the carbon protective coating in SCS6 fibre reinforced titanium alloys  

Microsoft Academic Search

Titanium matrix composites (SiC-fibre reinforced titanium alloys) are candidate materials for high temperature applications, e.g. in gas turbines. For this reason oxidation of the commonly applied SiC-fibre SCS-6 is investigated at temperatures of 400, 500 and 600°C in air up to a maximum time of 800h (for the last temperature). The initial 3.5?m thick protection layer of this fibre mainly

P. W. M Peters; J Hemptenmacher

2002-01-01

89

In vivo depth-resolved birefringence measurements of the human retinal nerve fiber layer by polarization-sensitive optical coherence tomography  

Microsoft Academic Search

To our knowledge, this is the first demonstration of in vivo depth-resolved birefringence measurements of the human retinal nerve fiber layer (RNFL) by use of polarization-sensitive optical coherence tomography (PS-OCT). Because glaucoma causes nerve fiber layer damage, which may cause loss of retinal birefringence, PS-OCT is a potentially useful technique for the early detection of glaucoma. We built a fiber-based

Barry Cense; Teresa C. Chen; B. Hyle Park; Mark C. Pierce; Johannes F. de Boer

2002-01-01

90

A comparison of the mechanical properties of phenol formaldehyde composites reinforced with banana fibres and glass fibres  

Microsoft Academic Search

Composites were fabricated using banana fibre and glass fibre with varying fibre length and fibre loading. The analysis of tensile, flexural and impact properties of these composites revealed that the optimum length of fibre required for banana fibre and glass fibre are different in phenol formaldehyde resole matrix. Both banana fibre and glass fibre reinforced composites show a regular trend

Seena Joseph; M. S Sreekala; Z Oommen; P Koshy; Sabu Thomas

2002-01-01

91

Birefringence measurement of the retinal nerve fiber layer by swept source polarization sensitive optical coherence tomography  

PubMed Central

A Swept Source Polarization-Sensitive Optical Coherence Tomography (SS-PS-OCT) instrument has been designed, constructed, and verified to provide high sensitivity depth-resolved birefringence and phase retardation measurements of the retinal nerve fiber layer. The swept-source laser had a center wavelength of 1059 nm, a full-width-half-max spectral bandwidth of 58 nm and an A-line scan rate of 34 KHz. Power incident on the cornea was 440 µW and measured axial resolution was 17 µm in air. A multiple polarization state nonlinear fitting algorithm was used to measure retinal birefringence with low uncertainty. Maps of RNFL phase retardation in a subject measured with SS-PS-OCT compare well with those generated using a commercial scanning laser polarimetry instrument. Peak-to-valley variation of RNFL birefringence given here is less than values previously reported at 840nm. PMID:21643283

Elmaanaoui, Badr; Wang, Bingqing; Dwelle, Jordan C.; McElroy, Austin B.; Liu, Shuang S.; Rylander, Henry G.; Milner, Thomas E.

2011-01-01

92

Abnormal climbing fibre-Purkinje cell synaptic connections in the essential tremor cerebellum.  

PubMed

Structural changes in Purkinje cells have been identified in the essential tremor cerebellum, although the mechanisms that underlie these changes remain poorly understood. Climbing fibres provide one of the major excitatory inputs to Purkinje cells, and climbing fibre-Purkinje cell connections are essential for normal cerebellar-mediated motor control. The distribution of climbing fibre-Purkinje cell synapses on Purkinje cell dendrites is dynamically regulated and may be altered in disease states. The aim of the present study was to examine the density and distribution of climbing fibre-Purkinje cell synapses using post-mortem cerebellar tissue of essential tremor cases and controls. Using vesicular glutamate transporter type 2 immunohistochemistry, we labelled climbing fibre-Purkinje cell synapses of 12 essential tremor cases and 13 age-matched controls from the New York Brain Bank. Normally, climbing fibres form synapses mainly on the thick, proximal Purkinje cell dendrites in the inner portion of the molecular layer, whereas parallel fibres form synapses on the thin, distal Purkinje cell spiny branchlets. We observed that, compared with controls, essential tremor cases had decreased climbing fibre-Purkinje cell synaptic density, more climbing fibres extending to the outer portion of the molecular layer, and more climbing fibre-Purkinje cell synapses on the thin Purkinje cell spiny branchlets. Interestingly, in essential tremor, the increased distribution of climbing fibre-Purkinje cell synapses on the thin Purkinje cell branchlets was inversely associated with clinical tremor severity, indicating a close relationship between the altered distribution of climbing fibre-Purkinje cell connections and tremor. These findings suggest that abnormal climbing fibre-Purkinje cell connections could be of importance in the pathogenesis of essential tremor. PMID:25273997

Lin, Chi-Ying; Louis, Elan D; Faust, Phyllis L; Koeppen, Arnulf H; Vonsattel, Jean-Paul G; Kuo, Sheng-Han

2014-12-01

93

Enhanced capacitance textile fibres for supercapacitors via an interfacial molecular templating process  

Microsoft Academic Search

The application of poly(2-methoxyaniline-5-sulfonic acid), PMAS, as a molecular template in a bi-layered co-polymerisation process onto a microporous activated carbon fibre is presented. This process produces a bound, compact molecular layer of PMAS, onto which polyaniline (PAni) or polypyrrole (PPy) is co-polymerized as a thin permeable layer coating the surface of the carbon fibre. The physical porous structure of the

Gregory J. Wilson; Mark G. Looney; A. G. Pandolfo

2010-01-01

94

Peripapillary retinal nerve fiber layer and foveal thickness in hypermetropic anisometropic amblyopia  

PubMed Central

Purpose To evaluate whether there was a difference in peripapillary retinal nerve fiber layer (RNFL) and foveal thickness between amblyopic and normal individuals with optical coherence tomography. Materials and methods Sixty patients, 30 patients with hypermetropic anisometropic amblyopia and 30 normal emmetropic subjects, were enrolled in this study. The eyes of the participants were divided into three groups: 30 eyes of 30 patients with amblyopia (A), 30 fellow eyes of the amblyopic patients (B), and 30 eyes of 30 normal subjects (C). Emmetropic normal subjects included cases with normal visual acuity and unremarkable ocular examinations. After routine ophthalmic examination, peripapillary retinal nerve fiber layer and foveal thickness measurements were measured by time-domain optical coherence tomography and compared among the three groups. Results The difference in RNFL thickness between amblyopic eyes, fellow eyes of the amblyopic patients, and normal eyes of the emmetropic subjects was not clinically significant. However, the mean foveal thickness was significantly thicker in amblyopic eyes versus the fellow eyes and normal subjects’ eyes. Conclusion Our results suggest that amblyopia seems to have an effect on the foveal thickness, but not on the RNFL thickness. PMID:24748770

Yalcin, Elvan; Balci, Ozlem

2014-01-01

95

Polyaniline fibres as electrodes  

Microsoft Academic Search

Polyaniline fibre microelectrodes prepared from a doped solution of polyaniline protonated with 2-acrylamido-2-methyl-1-propanesulphonic acid in dichloracetic acid were characterized electrochemically for the first time. Low scan rate cyclic voltammetry was used for characterisation in different acid electrolyte solutions, hydrochloric, nitric, perchloric, sulphuric and phosphoric, at low pH values with varying positive potential limits. Electrochemical impedance spectroscopy was also utilised. The

Rasa Pauliukaite; Christopher M. A. Brett; Andrew P. Monkman

2004-01-01

96

Oxidative stabilization of acrylic fibres  

Microsoft Academic Search

When acrylic fibres are heat treated for various times at 220 to 250 C, they form dark, insoluble structures of uncertain\\u000a chemical character which are inert to many strong oxidizing and reducing agents. The heat-treated fibres are, however, rapidly\\u000a decoloured by warm alkaline hypochlorite solutions. When fibres which have undergone short-time heat treatment are subjected\\u000a to the hypochlorite, incubation periods

S. S. Chen; J. Herms; L. H. Peebles; D. R. Uhlmann

1981-01-01

97

An investigation into the persistence of textile fibres on buried carcasses.  

PubMed

A significant amount of research has been carried out on fibres to aid the forensic scientist in determining the significance of these when found on a victim or suspect. This work has focused on open-air environments, and as such no research has been undertaken to examine the persistence of fibres on bodies in the burial environment. Wool and cotton fibres, known to fluoresce under ultraviolet (UV) light, were transferred onto the skin of four porcine (Sus scrofa) carcasses (two carcasses per fibre type). The number of fibres transferred was recorded from images taken under UV light. The remains were subsequently placed in four burial sites and left interred for 14 days. After this period the carcasses were excavated and lightly brushed down to remove the soil layer that had adhered to the skin. Once again photography under UV light was used to record the number of fibres which persisted on the skin. Results showed that after 14 days, wool and cotton fibres remain on the surface of the buried carcasses. In no circumstance was there a total loss of fibres suggesting that in such scenarios, the likelihood of finding fibres is high but the initial number of fibres transferred would be strongly diminished. This has important implications for both the excavation protocol for buried remains and the subsequent analysis for physical evidence. PMID:25002046

DeBattista, Roslyn; Tidy, Helen; Thompson, Tim J U; Robertson, Peter

2014-07-01

98

Introduction Short fibre reinforced thermoplastics are widely  

E-print Network

Introduction Short fibre reinforced thermoplastics are widely used for plastic part production because they can be processed with the same machines as classi- cal thermoplastics, but present enhanced, Injection moulding of fibre reinforced thermoplastics: integration of fibre orientation and mechanical

Paris-Sud XI, Université de

99

Retinal Nerve Fiber Layer Thickness Changes in Parkinson Disease: A Meta-Analysis  

PubMed Central

Background Parkinson disease (PD) is a neurodegenerative process that leads to a selective loss of dopaminergic neurons, mainly in the basal ganglia of the brain. Numerous studies have analyzed the ability of optical coherence tomography (OCT) to detect retinal nerve fiber layer (RNFL) thickness abnormalities and changes in PD, but the results have not always been consistent. Therefore, we carried out a meta-analysis to evaluate the RNFL thickness measured with OCT in PD. Methods and Findings Case-control studies were selected through an electronic search of the Cochrane Controlled Trials Register, PUBMED and EMBASE. For the continuous outcomes, we calculated the weighted mean difference (WMD) and 95% confidence interval (CI). The statistical analysis was performed by RevMan 5.0 software. Thirteen case-control studies were included in the present meta-analysis, containing a total of 644 eyes in PD patients and 604 eyes in healthy controls. The results of our study showed that there was a significant reduction in average RNFL thickness in patients with PD compared to healthy controls (WMD?=??5.76, 95% CI: ?8.99 to ?2.53, P?=?0.0005). Additionally, differences of RNFL thickness in superior quadrant (WMD?=??4.44, 95% CI: ?6.93 to ?1.94, P?=?0.0005), inferior quadrant (WMD?=??7.56, 95% CI: ?11.33 to ?3.78, P<0.0001), nasal quadrant (WMD?=??3.12, 95% CI: ?5.63 to ?0.61, P?=?0.01) and temporal quadrant (WMD?=??4.63, 95% CI: ?7.20 to ?2.06, P?=?0.0004) were all significant between the two groups. Conclusion In view of these results and the noninvasive nature of OCT technology, we surmise that OCT could be a useful tool for evaluating the progression of the Parkinson disease. Trial Registration ClinicalTrials.gov NCT01928212 PMID:24465663

Yu, Ji-guo; Feng, Yi-fan; Xiang, Yi; Huang, Jin-hai; Savini, Giacomo; Parisi, Vincenzo; Yang, Wan-ju; Fu, Xun-an

2014-01-01

100

High-power fibre lasers  

NASA Astrophysics Data System (ADS)

Fibre lasers are now associated with high average powers and very high beam qualities. Both these characteristics are required by many industrial, defence and scientific applications, which explains why fibre lasers have become one of the most popular laser technologies. However, this success, which is largely founded on the outstanding characteristics of fibres as an active medium, has only been achieved through researchers around the world striving to overcome many of the limitations imposed by the fibre architecture. This Review focuses on these limitations, both past and current, and the creative solutions that have been proposed for overcoming them. These solutions have enabled fibre lasers to generate the highest diffraction-limited average power achieved to date by solid-state lasers.

Jauregui, Cesar; Limpert, Jens; Tünnermann, Andreas

2013-11-01

101

Random distributed feedback fibre lasers  

NASA Astrophysics Data System (ADS)

The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors-random distributed feedback fibre laser-was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (˜0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the generation of a stationary near-Gaussian beam with a narrow spectrum. A random distributed feedback fibre laser has efficiency and performance that are comparable to and even exceed those of similar conventional fibre lasers. The key features of the generated radiation of random distributed feedback fibre lasers include: a stationary narrow-band continuous modeless spectrum that is free of mode competition, nonlinear power broadening, and an output beam with a Gaussian profile in the fundamental transverse mode (generated both in single mode and multi-mode fibres). This review presents the current status of research in the field of random fibre lasers and shows their potential and perspectives. We start with an introductory overview of conventional distributed feedback lasers and traditional random lasers to set the stage for discussion of random fibre lasers. We then present a theoretical analysis and experimental studies of various random fibre laser configurations, including widely tunable, multi-wavelength, narrow-band generation, and random fibre lasers operating in different spectral bands in the 1-1.6 ?m range. Then we discuss existing and future applications of random fibre lasers, including telecommunication and distributed long reach sensor systems. A theoretical description of random lasers is very challenging and is strongly linked with the theory of disordered systems and kinetic theory. We outline two key models governing the generation of random fibre lasers: the average power balance model and the nonlinear Schrödinger equation based model. Recently invented random distributed feedback fibre lasers represent a new and exciting field of research that brings together such diverse areas of science as laser physics, the theory of disordered systems, fibre optics and nonlinear science. Stable random generation in optical fibre opens up new possibilities for research on wave transport and localization in disordered media. We hope that this review will provide background information for research in various fields and will stimulate cross-disciplinary collaborat

Turitsyn, Sergei K.; Babin, Sergey A.; Churkin, Dmitry V.; Vatnik, Ilya D.; Nikulin, Maxim; Podivilov, Evgenii V.

2014-09-01

102

Preservation of Archaeological Textiles Through Fibre Mineralization  

Microsoft Academic Search

Copper mineralized plant fibre cordage (c. 1500) found at an archaeological site was used to study fibre microstructural degradation in response to a specific burial environment and the preservation of textiles through mineralization. The process of cellulose fibre mineralization was simulated in the laboratory in an effort to prepare mineralized plant fibres under known conditions. A model for dyeing cellulosic

H. L. Chen; K. A. Jakes; D. W. Foreman

1998-01-01

103

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

104

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

105

Ultrasonic assembly of anisotropic short fibre reinforced composites.  

PubMed

We report the successful manufacture of short fibre reinforced polymer composites via the process of ultrasonic assembly. An ultrasonic device is developed allowing the manufacture of thin layers of anisotropic composite material. Strands of unidirectional reinforcement are, in response to the acoustic radiation force, shown to form inside various matrix media. The technique proves suitable for both photo-initiator and temperature controlled polymerisation mechanisms. A series of glass fibre reinforced composite samples constructed in this way are subjected to tensile loading and the stress-strain response is characterised. Structural anisotropy is clearly demonstrated, together with a 43% difference in failure stress between principal directions. The average stiffnesses of samples strained along the direction of fibre reinforcement and transversely across it were 17.66±0.63MPa and 16.36±0.48MPa, respectively. PMID:24360815

Scholz, M-S; Drinkwater, B W; Trask, R S

2014-04-01

106

Lignin manipulation for fibre improvement  

Microsoft Academic Search

For centuries plant fibres have been used in a number of commercial areas including textiles, construction, paper and pulp,\\u000a reinforced composites, and as biomass for energy production. These fibres come from a whole host of crops ranging from cotton,\\u000a jute and flax for textiles; wood crops such as poplar, eucalyptus and conifers for paper and pulp; and cereal crops such

Jennifer Stephens; Claire Halpin

107

Dietary fibre: a roughage guide.  

PubMed

The concept of dietary fibre is a complex one that incorporates the physical and physiological functions of fibre and its effects both systemically and local to the gastro-intestinal tract. Dietary fibre can be usefully classified according to its solubility and fermentability, which allows rational clinical application. Fibres may act in several ways including by gel-forming effects in the stomach and small intestine, by its fermentation by colonic bacteria, by a 'mop and sponge' effect, and via concomitant changes in other aspects of the diet. These actions lead to potentially beneficial effects in the gastro-intestinal tract and systemically, such as lowering serum cholesterol and improving glycaemic control. Dietary fibre has been implicated in multiple clinical situations but, although an extensive literature on putative actions and proposed physiological bases is available, high-level evidence of efficacy is limited. Nevertheless, encouraging the intake of a high-fibre diet is likely to have a range of health benefits and physicians are encouraged to follow simple practical guidelines in their everyday practice. PMID:12823674

James, S L; Muir, J G; Curtis, S L; Gibson, P R

2003-07-01

108

The effect of acute intraocular pressure elevation on peripapillary retinal thickness, retinal nerve fiber layer thickness and retardance  

PubMed Central

Purpose To determine whether acutely elevated intraocular pressure (IOP) alters peripapillary retinal thickness, retinal nerve fiber layer thickness (RNFLT) or retardance. Methods Nine adult non-human primates were studied under isoflurane anesthesia. Retinal and RNFL thicknesses were measured by spectral domain optical coherence tomography 30 min after IOP was set to 10 mmHg and 60 min after IOP was set to 45 mmHg. RNFL retardance was measured by scanning laser polarimetery in 10 min intervals for 30 min while IOP was 10 mmHg, then for 60 min while IOP was 45 mmHg, then for another 30 min after IOP was returned to 10 mmHg. Results RNFLT measured 1120 ?m from the ONH center decreased from 118.1 ± 9.3 ?m at an IOP of 10 mmHg to 116.5 ± 8.4 ?m at 45 mmHg, or by 1.4 ± 1.8% (p<0.0001). There was a significant interaction between IOP and eccentricity (p=0.0006). Within 800 ?m of the ONH center, the RNFL was 4.9 ± 3.4% thinner 60 min after IOP elevation to 45 mmHg (p<0.001), but unchanged for larger eccentricities. The same pattern was observed for retinal thickness, with 1.1 ± 0.8% thinning overall at 45 mmHg (p<0.0001), and a significant effect of eccentricity (p<0.0001) whereby the retina was 4.8 ± 1.2% thinner (p<0.001) within 800 ?m, but unchanged beyond that. Retardance increased by a maximum of 2.2 ± 1.1% 60 min after IOP was increased to 45 mmHg (p=0.0031). Conclusions The effects of acute IOP elevation on retinal thickness, RNFL thickness and retardance were minor, limited to the immediate ONH surround and unlikely to have meaningful clinical impact. PMID:19420342

Fortune, Brad; Yang, Hongli; Strouthidis, Nicholas G.; Cull, Grant A.; Grimm, Jonathan L.; Downs, J. Crawford; Burgoyne, Claude F.

2009-01-01

109

Friction surface evolution of carbon fibre reinforced carbon\\/silicon carbide (C f\\/C-SiC) composites  

Microsoft Academic Search

A study is reported on the development of friction surface of carbon fibre reinforced ceramic composites through microstructural image registration of the surface after a range of braking stops on a laboratory-scale dynamometer test rig. It has been found that a steady friction transfer layer is developed in silicon regions; in carbon fibre\\/carbon and most silicon carbide regions, the friction

Yuan Wang; Houzheng Wu

2010-01-01

110

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

111

Wetting of flexible fibre arrays.  

PubMed

Fibrous media are functional and versatile materials, as demonstrated by their ubiquity both in natural systems such as feathers and adhesive pads and in engineered systems from nanotextured surfaces to textile products, where they offer benefits in filtration, insulation, wetting and colouring. The elasticity and high aspect ratios of the fibres allow deformation under capillary forces, which cause mechanical damage, matting self-assembly or colour changes, with many industrial and ecological consequences. Attempts to understand these systems have mostly focused on the wetting of rigid fibres or on elastocapillary effects in planar geometries and on a fibre brush withdrawn from an infinite bath. Here we consider the frequently encountered case of a liquid drop deposited on a flexible fibre array and show that flexibility, fibre geometry and drop volume are the crucial parameters that are necessary to understand the various observations referred to above. We identify the conditions required for a drop to remain compact with minimal spreading or to cause a pair of elastic fibres to coalesce. We find that there is a critical volume of liquid, and, hence, a critical drop size, above which this coalescence does not occur. We also identify a drop size that maximizes liquid capture. For both wetting and deformation of the substrates, we present rules that are deduced from the geometric and material properties of the fibres and the volume of the drop. These ideas are applicable to a wide range of fibrous materials, as we illustrate with examples for feathers, beetle tarsi, sprays and microfabricated systems. PMID:22358841

Duprat, C; Protière, S; Beebe, A Y; Stone, H A

2012-02-23

112

Multifunctional, supramolecular, continuous artificial nacre fibres  

PubMed Central

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. PMID:23097689

Hu, Xiaozhen; Xu, Zhen; Gao, Chao

2012-01-01

113

Myelinated nerve fibres in the CNS.  

PubMed

(1) Lamellated glial sheaths surrounding axons, and electrogenetically active axolemmal foci have evolved independently in widely different phyla. In addition to endowing the axons to conduct trains of impulses at a high speed, myelination and node formation results in a remarkable saving of space and energy. This is particularly important in the CNS, where space is restricted. Unlike the PNS, most CNS axons are myelinated, and several axons may be myelinated by a single cell. This adds further economy of space and energy. On the other hand the high level of complexity of the CNS white matter makes it vulnerable. There are several different kinds of disease affecting myelinated fibre tracts, particularly with respect to CNS white matter. (2) The CNS node of Ranvier presents a more complex structure the larger the fibre. The constricted nodal axon is encircled by perinodal astrocytic processes which contain large gliosomes and emit delicate processes towards the nodal axolemma. One astrocyte may project to several nodes. The node gap contains a polyanionic extracellular material. (3) Lamellated myelinoid bodies are frequent along paranodes of large myelinated CNS fibres. These bodies probably form through budding off from the paranodal myelin sheath. Similar bodies are seen inside astrocytes and microglia. The observation that these bodies are Marchi-positive and argyrophilic, and the presence of acid phosphatase activity around myelinoid bodies inside microglia suggests that they might represent degenerating myelin quanta, involved in the turnover of large myelin sheaths. This putative quantal release and breakdown of myelin material must be compensated for by a production of new myelin at other sites. Therefore, myelination may be viewed as a process that continues throughout life. (4) Biochemical analysis of a sub-cellular fraction enriched in myelinoid bodies shows that these bodies have a composition basically similar to that of myelin. However, breakdown products of myelin constituents, as well as exotic high molecular substances, not present in conventional myelin, can also be found. In addition, the myelinoid body fraction contains proteolytic activity. Studies using isotope labelling of myelin proteins show a source-product relation between myelin and myelinoid bodies. Altogether these data strongly support the hypothesis that myelinoid bodies reflect the catabolic side of myelin turnover. (5) Axons in the nerve fibre layer of the adult rat retina are all unmyelinated, although their diameters range up to over 2 microns. These axons exhibit focally differentiated axolemmal areas. At these sites the axolemma presents a dense undercoating with externally associated Müller cell processes or astrocytic processes.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8441812

Hildebrand, C; Remahl, S; Persson, H; Bjartmar, C

1993-03-01

114

Processing stainless steel fibre reinforced NiAl matrix composites by reactive hot pressing  

Microsoft Academic Search

Stainless steel fibres (SSF) were first wound and then plated with electrical nickel film. Alternative layers of these properly\\u000a spaced Ni-coated stainless steel fibres (SSF–Ni) and aluminum foils were then stacked and diffusion bonded at 500 C, 100\\u000a MPa in vacuum for 10 min to produce an SSF–Ni–Al precursor. Lower-temperature reactive hot pressing (RHP) at 700 C, a process\\u000a employed

SHOU-YI CHANG; SU-JIEN LIN

1997-01-01

115

The Development of a Continuum Damage Model for Fibre Metal Laminate Structures  

Microsoft Academic Search

Fibre Metal Laminates (FMLs) are a family of materials consisting of alternating layers of thin metal sheets and fibre-reinforced\\u000a plastic. Glass composite based FMLs, commercially available under the name GLARE, have recently found application in the aircraft\\u000a industry due to their excellent fatigue performance and impact properties. This work aims to develop a computational damage\\u000a model for GLARE for use

Ronan M. Frizzell; Conor T. McCarthy; Daire Cronin; Michael A. McCarthy; Ronan M. O’Higgins

116

Mechanical Property Evaluation of Coconut Fibre.  

E-print Network

??This thesis workis eco-friendly,agricultural material.Examples of some non-wood fibre material are also discussed briefly but with emphasis on coconut fibre to evaluate its mechanical properties.Experiments… (more)

Bolarinwa, Oluseun

2008-01-01

117

A high-energy fibre-to-fibre connection for direct optical initiation systems  

NASA Astrophysics Data System (ADS)

Direct Optical Initiation (DOI), uses a moderate energy laser to shock initiate secondary explosives, via either a flyer plate or exploding metal foil. DOI offers significant performance and safety advantages over conventional electrical initiation. Optical fibres are used to transport the optical energy from the laser to the explosive device. A DOI system comprises of a laser, one or more optical fibres, and one or more laser detonators. Realisation of a DOI system is greatly eased by the use of fibre-to-fibre connections, allowing for easy integration into bulkheads or other interfaces, such as firing tanks and environmental test chambers. Fibres to fibre connectors capable of transmitting the required energy densities are not commercially available. Energy densities in the region of 35 J cm-2 are required for initiation, above the damage threshold of typical optical fibres. Laser-induced damage is typically caused by laser absorption at the input face due to imperfections in the surface polishing. To successfully transmit energy densities for DOI, a high quality fibre end face finish is required. A fibre-to-fibre connection utilizing micro-lens array injection into a large-core, tapered optical fibre, a hermetic fibre bulkhead feedthrough, and a disposable test fibre has been developed. This permits easy connection of test detonators or components, with the complex free-space to fibre injection simplified to a single operation. The damage threshold and transmission losses of the fibre-to-fibre connection have been established for each interface.

Bowden, M. D.; Knowles, S. L.

2012-11-01

118

Liquid crystal assisted optical fibres.  

PubMed

Microstructured fibres which consist of a circular step index core and a liquid crystal inclusion running parallel to this core are investigated. The attenuation and electro-optic effects of light coupled into the core are measured. Coupled mode theory is used to study the interaction of core modes with the liquid crystal inclusion. The experimental and theoretical results show that these fibres can exhibit attenuation below 0.16 dB cm(-1) in off-resonant wavelength regions and still have significant electro-optic effects which can lead to a polarisation extinction of 6 dB cm(-1). PMID:24514987

Wahle, M; Kitzerow, H-S

2014-01-13

119

Composites reinforced with cellulose based fibres  

Microsoft Academic Search

This review article concerning natural and man-made cellulose fibre reinforced plastics, introduces possible applications of this material group. The physical properties of natural fibres are mainly determined by the chemical and physical composition, such as the structure of fibres, cellulose content, angle of fibrils, cross-section, and by the degree of polymerization. Only a few characteristic values, but especially the specific

A. K Bledzki; J Gassan

1999-01-01

120

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 PMID:8226288

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

1993-01-01

121

Comparison of bast fibre yield and mechanical fibre properties of hemp ( Cannabis sativa L.) cultivars  

Microsoft Academic Search

High stem yield and high bast fibre content in stem are generally accepted as important properties for fibre hemp (Cannabis sativa L.) Quality demands for fibre used in the new non-woven products have not yet been defined. The Ukrainian monoecious fibre hemp cv. Uso 11 was compared with 13 other fibre hemp cultivars in 1995–1997 in Finland (latitude 60°49? N).

Hannele S Sankari

2000-01-01

122

`Giant' Fibres in Dragonfly Nymphs  

Microsoft Academic Search

A PRELIMINARY study of transverse and horizontal sections through the ventral nerve cord of late instar nymphs of Anax imperator (Anisoptera) has revealed several notable features. Accurate counts of the number of fibres within the commissures have shown that these range continuously from 0 to 16 µ, as set out in the accompanying histogram (Fig. 1). The total number of

G. M. Hughes

1953-01-01

123

Optical fibre laser velocimetry: a review  

NASA Astrophysics Data System (ADS)

The applications of optical fibre technology to laser velocimetry are diverse and often critical to their successful implementation, particularly in harsh environments. Applications range from the use of optical fibres for beam delivery and scattered light collection, aiding the miniaturization of instrument probes, to the use of imaging fibre bundles for imaging the flow field in planar velocimetry systems. Optical fibre techniques have also been used in signal processing, for example fibre frequency shifters, and optical fibre devices such as amplifiers and lasers have been exploited. This paper will review the use of optical fibres in point-wise laser velocimetry techniques such as laser Doppler velocimetry and laser transit anemometry, as well as in planar measurement techniques such as particle imaging velocimetry and planar Doppler velocimetry.

Charrett, Thomas O. H.; James, Stephen W.; Tatam, Ralph P.

2012-03-01

124

'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. PMID:23112385

Ishizuka, Hisao

2012-01-01

125

Ytterbium fibre laser with a heavily Yb{sup 3+}-doped glass fibre core  

SciTech Connect

The use of optical fibres with a high concentration of active ions in the fibre core allows the reduction of the active fibre length and the increase in the threshold powers of various nonlinear effects in the fibre, thereby increasing the maximum output power of fibre lasers. For this purpose, we manufactured a highly concentrated ytterbium-doped ({approx}1.0x10{sup 21}cm{sup -3}) phosphate glass for the active fibre core and a pure glass of a similar composition for the fibre cladding. A single-mode fibre is fabricated from these glasses and generation is obtained in an ytterbium laser based on this fibre with the slope efficiency of no less than 60% at a wavelength of 975 nm. (letters)

Bufetov, Igor' A; Semenov, S L; Kosolapov, A F; Mel'kumov, Mikhail A; Dudin, V V; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Galagan, B I; Denker, B I; Osiko, Vyacheslav V; Sverchkov, S E [Laser Materials and Technology Research Center, A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2006-03-31

126

Zinc transporter 3 immunohistochemical tracing of sprouting mossy fibres.  

PubMed

Zinc transporter 3 (ZNT3) has been shown to transport zinc ions from the cytosol into presynaptic vesicles in the mammalian brain. Several studies have stated that the zinc ion containing synaptic vesicles of zinc-enriched neurons (ZEN) are loaded with ZNT3 proteins in their membranes. This fact makes it possible to trace sprouting mossy fibres in the temporal lobe epileptic hippocampus. In the present study, we examined the expression and distribution patterns of ZNT3 protein and chelatable zinc ions in the mouse hippocampus after pilocarpine treatment. Our results demonstrate that both ZNT3 immunostaining and autometallography reveal identical patterns of sprouting mossy fibres in the inner molecular layer in the mouse hippocampus. Using ZNT3 immuno-electron microscopic analysis we confirmed the presence of ectopic mossy fibre terminals in the inner molecular layer and found additionally by immuno-blotting a significant increase of ZNT3 in the pilocarpine-treated mouse hippocampi compared to age-matched controls. The increase of ZNT3 after pilocarpine treatment was time-dependent. The results support the notion that ZNT3 immunohistochemistry provides an excellent tool for tracing sprouting of ZEN terminals. The progressive increase of ZNT3 immunostaining in the temporal lobe epileptic hippocampus may relate to the increased levels of vesicular zinc ions during seizure. PMID:18406010

Chi, Zhi-Hong; Wang, Xin; Cai, Ji-Qun; Stoltenberg, Meredin; Danscher, Gorm; Wang, Zhan-You

2008-06-01

127

Parvalbumin immunoreactive neurons and fibres in the teleost cerebellum.  

PubMed

The distribution of parvalbumin- (PV) immunopositive cell bodies and fibres in the cerebellum of two species of freshwater teleosts (Salmo gairdneri and Barbus meridonalis) was studied using a monoclonal antibody and the avidin-biotin immunoperoxidase technique. A clear laminated pattern of PV immunoreactivity was observed. After PV-immunostaining, Purkinje cells were strongly labelled in their cell bodies, the initial segments of the axons and the dendritic trees. In the molecular layer, only the dendritic branches of the Purkinje cells were PV-positive. In the granule cell layer, extensive axonal plexuses and scattered cell bodies were observed. Most of the immunopositive perikarya were unequivocally identified as displaced Purkinje cells, whereas a reduced number of smaller neurons with unstained dendrites was also found. Eurydendroid cells, the efferent neurons of the teleost cerebellum, were negative; however, they were impinged upon by numerous PV-positive boutons, corresponding to terminals of Purkinje cell axons. Parallel fibres and climbing fibres, as well as stellate cells and granule cells were negative. Basket cells (or deep stellate cells) whose existence in the teleost cerebellum is discussed, were also not observed. The immunoreactivity distribution pattern for PV in the teleost cerebellum differs from previous observations on the localization of this protein in the cerebellum of amniotes. PMID:1609963

Alonso, J R; Arèvalo, R; Briñòn, J G; Lara, J; Weruaga, E; Aijòn, J

1992-01-01

128

Nanocellulose enhanced interfaces in truly green unidirectional fibre reinforced composites  

Microsoft Academic Search

One of the main problems in fabricating natural fibre reinforced polymers is the poor adhesion between intrinsically polar plant fibres and non-polar polymer matrices. We have developed a truly green technique of modifying natural fibre (hemp and sisal) surfaces to improve the interaction between the fibres and polymers by attaching nano-scale bacterial cellulose to the fibre surfaces. These modified natural

Julasak Juntaro; Marion Pommet; Athanasios Mantalaris; Milo Shaffer; Alexander Bismarck

2007-01-01

129

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

130

Extensions of Fibre Bundle Models  

Microsoft Academic Search

The fibre bundle model is one of the most important theoretical approaches to investigate the fracture and breakdown of disordered\\u000a media extensively used both by the engineering and physics community. We present the basic construction of the model and provide\\u000a a brief overview of recent results focusing mainly on the physics literature. We discuss the limitations of the model to

F. Kun; F. Raischel; R. C. Hidalgo; H. J. Herrmann

131

International Year of Natural Fibres  

NSDL National Science Digital Library

The United Nations Food and Agriculture Organization has designated 2009 as the International Year of Natural Fibres. The goals of this year are three-fold: to raise the profile of natural fibers in a market increasingly dominated by synthetic fibers; convey the value of using natural fibers to consumers; and help sustain the income of the often poor farmers of natural fibers. This very interesting website for the "Year" is available in English, French, Chinese and Spanish. Visitors interested in learning about the history of natural fibers, as well as what different types of natural fibers there are, what they look like, and what they are used for, will find this website fits the bill. On the menu on the far right side of the page, visitors can click on the link "15 Natural Fibres" to peruse a brief history and learn about the different natural fibers that come from plants and animals. Most of the fibers featured include information on what the fiber is, who produces it, how it's produced, and how much is produced, which can be accessed by rolling the mouse over the name or picture of the fiber, and clicking. The link on the menu on the far right side of the page entitled "Fibre Stories" has four stories about new innovations for several different natural fibers. There is a story about cotton in Asia, hemp in China, alpaca in Peru, and sisal in Tanzania. Events around the world celebrating the International Year of Natural Fibres can be found on the far right menu, at the "Events" link.

132

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

133

Dietary fibre in foods: a review.  

PubMed

Dietary fibre is that part of plant material in the diet which is resistant to enzymatic digestion which includes cellulose, noncellulosic polysaccharides such as hemicellulose, pectic substances, gums, mucilages and a non-carbohydrate component lignin. The diets rich in fibre such as cereals, nuts, fruits and vegetables have a positive effect on health since their consumption has been related to decreased incidence of several diseases. Dietary fibre can be used in various functional foods like bakery, drinks, beverages and meat products. Influence of different processing treatments (like extrusion-cooking, canning, grinding, boiling, frying) alters the physico- chemical properties of dietary fibre and improves their functionality. Dietary fibre can be determined by different methods, mainly by: enzymic gravimetric and enzymic-chemical methods. This paper presents the recent developments in the extraction, applications and functions of dietary fibre in different food products. PMID:23729846

Dhingra, Devinder; Michael, Mona; Rajput, Hradesh; Patil, R T

2012-06-01

134

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

PubMed Central

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 the nature of the developmental genetic transformations that accompanied domestication and crop improvement, we studied the transcriptomes of cotton fibres from wild and domesticated accessions over a developmental time course. Results Fibre cells were harvested between 2 and 25 days post-anthesis and encompassed the primary and secondary wall synthesis stages. Using amplified messenger RNA and a custom microarray platform designed to interrogate expression for 40,430 genes, we determined global patterns of expression during fibre development. The fibre transcriptome of domesticated cotton is far more dynamic than that of wild cotton, with over twice as many genes being differentially expressed during development (12,626 versus 5273). Remarkably, a total of 9465 genes were diagnosed as differentially expressed between wild and domesticated fibres when summed across five key developmental time points. Human selection during the initial domestication and subsequent crop improvement has resulted in a biased upregulation of components of the transcriptional network that are important for agronomically advanced fibre, especially in the early stages of development. About 15% of the differentially expressed genes in wild versus domesticated cotton fibre have no homology to the genes in databases. Conclusions We show that artificial selection during crop domestication can radically alter the transcriptional developmental network of even a single-celled structure, affecting nearly a quarter of the genes in the genome. Gene expression during fibre development within accessions and expression alteration arising from evolutionary change appears to be 'modular' - complex genic networks have been simultaneously and similarly transformed, in a coordinated fashion, as a consequence of human-mediated selection. These results highlight the complex alteration of the global gene expression machinery that resulted from human selection for a longer, stronger and finer fibre, as well as other aspects of fibre physiology that were not consciously selected. We illustrate how the data can be mined for genes that were unwittingly targeted by aboriginal and/or modern domesticators during crop improvement and/or which potentially control the improved qualities of domesticated cotton fibre. See Commentary: http://www.biomedcentral.com/1741-7007/8/137 PMID:21078138

2010-01-01

135

OPTICAL FIBRES: Optical properties of active bismuth centres in silica fibres containing no other dopants  

NASA Astrophysics Data System (ADS)

Optical fibre preforms and fibres with a bismuth-doped silica core containing no other dopants have been fabricated by the powder-in-tube technique. The optical loss has been measured for the first time in such fibres in a wide spectral range, from 190 to 1700 nm. We have studied the luminescence of active bismuth centres and the luminescence lifetime for some of their bands in both the preforms and the fibres drawn out from them.

Bufetov, Igor'A.; Semenov, S. L.; Vel'miskin, V. V.; Firstov, Sergei V.; Bufetova, G. A.; Dianov, Evgenii M.

2010-09-01

136

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

137

Impact loading on fibre metal laminates  

Microsoft Academic Search

Static identation and low and high velocity impact tests are conducted on specimens with a circular clamped test area. Monolithic A1 2024-T3 and 7075-T6, various grades of Fibre Metal Laminates (FML), and composites are tested. The energy to create the first crack for FML with aramid and carbon fibres is comparable to fibre reinforced composite materials and is relatively low

A. Vlot

1996-01-01

138

Development of polyester and polyamide conductive fibre  

Microsoft Academic Search

Conducting polyester PET and polyamide PA-6 fibre and fabrics were prepared by in-situ chemical oxidative polymerisation using super critical fluid assisted process. The fibre materials and cloths produced were characterized by means of FTIR, WAXD, SEM, and DSC and two-probe resistivity. The samples were studied also by means of washing them several times. Homogeneous treated fibre materials with sustainable properties

Ali Harlin; Pertti Nousiainen; Arja Puolakka; Jani Pelto; Juha Sarlin

2005-01-01

139

Smooth light extraction in lighting optical fibre  

NASA Astrophysics Data System (ADS)

Recent advances in LED technology have relegated the use of optical fibre for general lighting, but there are several applications where it can be used as scanners lighting systems, daylight, cultural heritage lighting, sensors, explosion risky spaces, etc. Nowadays the use of high intensity LED to inject light in optical fibre increases the possibility of conjugate fibre + LED for lighting applications. New optical fibres of plastic materials, high core diameter up to 12.6 mm transmit light with little attenuation in the visible spectrum but there is no an efficient and controlled way to extract the light during the fibre path. Side extracting fibres extracts all the light on 2? angle so is not well suited for controlled lighting. In this paper we present an extraction system for mono-filament optical fibre which provides efficient and controlled light distribution. These lighting parameters can be controlled with an algorithm that set the position, depth and shape of the optical extraction system. The extraction system works by total internal reflection in the core of the fibre with high efficiency and low cost. A 10 m length prototype is made with 45° sectional cuts in the fibre core as extraction system. The system is tested with a 1W white LED illuminator in one side.

Fernandez-Balbuena, A. A.; Vazquez-Molini, D.; Garcia-Botella, A.; Martinez-Anton, J. C.; Bernabeu, E.

2011-10-01

140

Photonic bandgap fibre oscillators and amplifiers  

NASA Astrophysics Data System (ADS)

In the search for ever higher output power or energy from fibre oscillators or amplifiers a nowadays mature technology relies on enlarging the fibre mode area. Broadening of the core diameter, all other things being equal, inevitably yields a multimode fibre, thereby dramatically limiting the device usefulness. Various strategies have been deployed to design and manufacture single transverse mode fibre oscillators and amplifiers, among which making use of the so-called photonic bandgap effect to restrict the modal population seems promising. Helped by efficient and reliable numerical tools the design of large mode area singlemode photonic bandgap fibres is presented. Two fibres with 20-?m and 40-?m core diameter, both of them heavily doped with Yb 3+ ions, have been fabricated by the widespread modified chemical vapour deposition process and are shown to behave properly when used as the core element of either continuous wave oscillators or femtosecond amplifiers. Good output beam quality (M 2 parameter spanning from 1.12 to 1.5 for the set of fibres studied) and high slope efficiency of 80% in cw oscillation regime are demonstrated. Furthermore the 40-?m core diameter fibre is shown to be resilient to tight bending down to 7.5-cm radius. The stack-and-draw process makes it easy to tailor the outer cladding so that a large numerical aperture can be reached. Subsequently, from this air-clad fibre, 500 fs 47 W pulses at 35 MHz are obtained from a two-stage chirped pulse amplification system.

Février, S.; Gaponov, D.; Devautour, M.; Roy, P.; Daniault, L.; Hanna, M.; Papadopoulos, D. N.; Druon, F.; Georges, P.; Likhachev, M. E.; Salganskii, M. Y.; Yashkov, M. V.

2010-12-01

141

Space-division multiplexing in optical fibres  

NASA Astrophysics Data System (ADS)

Optical communication technology has been advancing rapidly for several decades, supporting our increasingly information-driven society and economy. Much of this progress has been in finding innovative ways to increase the data-carrying capacity of a single optical fibre. To achieve this, researchers have explored and attempted to optimize multiplexing in time, wavelength, polarization and phase. Commercial systems now utilize all four dimensions to send more information through a single fibre than ever before. The spatial dimension has, however, remained untapped in single fibres, despite it being possible to manufacture fibres supporting hundreds of spatial modes or containing multiple cores, which could be exploited as parallel channels for independent signals.

Richardson, D. J.; Fini, J. M.; Nelson, L. E.

2013-05-01

142

Photonic Crystal Fibres for Coherent Supercontinuum Generation.  

E-print Network

??Inthisresearchphotoniccrystalfibresweredevelopedforthepurposeofgeneratingcoherent supercontinua. Two photonic crystal fibres were fabricated with all-normal group velocity dispersionprofiles, withlow dispersion atpump wavelengths 800 nm and 1064 nm. Supercontinua generatedusing these… (more)

Hooper, Lucy

2012-01-01

143

Reduced fibre breakage in a glass-fibre reinforced thermoplastic through foaming  

E-print Network

Reduced fibre breakage in a glass-fibre reinforced thermoplastic through foaming G. Zhang, M of vehicles, one sees increased usage of reinforced thermoplastic composites for their molded parts. Increased for this growth [1]. These thermoplastic composites incorporate discontinuous glass fibres, either long (1­25 mm

Thompson, Michael

144

Correlation between macular changes and the peripapillary nerve fiber layer in primary open angle glaucoma  

PubMed Central

Glaucoma is a leading cause of blindness and the early diagnosis is crucial for treatment and follow-up in the progression of the disease. Objective: To evaluate the changes in mean macular thickness and volume and compare them with the mean thickness of the peripapillary nerve fiber layer in primary open angle glaucoma, using Time Domain (TD) optical coherence tomography ( OCT). Method: The examinations were conducted on 275 eyes of 138 patients, as it follows: 203 eyes of 102 patients diagnosed with primary open angle glaucoma in various stages of evolution, representing the study group, and 72 normal eyes from 36 patients, representing the control group. The study was conducted from March 2010 to December 2012. All the patients gave their consent, in accordance with the Helsinki Declaration. The study group showed a decrease in mean macular thickness and volume, as well as mean thickness of the peripapillary nerve fiber layer (RNFL) compared to the control group. According to the OCT measurements, the results of the study have shown that the decrease of the mean thickness of the RNFL is a better differentiator between glaucomatous and normal eyes compared to the decrease of the mean macular thickness and volume. PMID:24653759

Manasia, D; Voinea, L; Vasinca, ID; Alexandrescu, C

2014-01-01

145

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

146

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

147

Effect of boron oxide addition on fibre drawing, mechanical properties and dissolution behaviour of phosphate-based glass fibres with fixed 40, 45 and 50?mol% P2O5.  

PubMed

Previous studies investigating manufacture of phosphate-based glass fibres from glasses fixed with P2O5 content less than 50?mol% showed that continuous manufacture without breakage was very difficult. In this study, nine phosphate-based glass formulations from the system P2O5-CaO-Na2O-MgO-B2O3 were prepared with P2O5 contents fixed at 40, 45 and 50?mol%, where Na2O was replaced by 5 and 10?mol% B2O3 and MgO and CaO were fixed to 24 and 16?mol%, respectively. The effect of B2O3 addition on the fibre drawing, fibre mechanical properties and dissolution behaviour was investigated. It was found that addition of 5 and 10?mol% B2O3 enabled successful drawing of continuous fibres from glasses with phosphate (P2O5) contents fixed at 40, 45 and 50?mol%. The mechanical properties of the fibres were found to significantly increase with increasing B2O3 content. The highest tensile strength (1200?±?130?MPa) was recorded for 45P2O5-16CaO-5Na2O-24MgO-10B2O3 glass fibres. The fibres were annealed, and a comparison of the mechanical properties and mode of degradation of annealed and non-annealed fibres were investigated. A decrease in tensile strength and an increase in tensile modulus were observed for the annealed fibres. An assessment of the change in mechanical properties of both the annealed and non-annealed fibres was performed in phosphate-buffered saline (PBS) at 37? for 28 and 60 days, respectively. Initial loss of mechanical properties due to annealing was found to be recovered with degradation. The B2O3-containing glass fibres were found to degrade at a much slower rate as compared to the non-B2O3-containing fibres. Both annealed and non-annealed fibres exhibited a peeling effect of the fibre's outer layer during degradation. PMID:24939962

Sharmin, Nusrat; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

2014-11-01

148

Effect of boron oxide addition on fibre drawing, mechanical properties and dissolution behaviour of phosphate-based glass fibres with fixed 40, 45 and 50?mol% P2O5  

PubMed Central

Previous studies investigating manufacture of phosphate-based glass fibres from glasses fixed with P2O5 content less than 50?mol% showed that continuous manufacture without breakage was very difficult. In this study, nine phosphate-based glass formulations from the system P2O5-CaO-Na2O-MgO-B2O3 were prepared with P2O5 contents fixed at 40, 45 and 50?mol%, where Na2O was replaced by 5 and 10?mol% B2O3 and MgO and CaO were fixed to 24 and 16?mol%, respectively. The effect of B2O3 addition on the fibre drawing, fibre mechanical properties and dissolution behaviour was investigated. It was found that addition of 5 and 10?mol% B2O3 enabled successful drawing of continuous fibres from glasses with phosphate (P2O5) contents fixed at 40, 45 and 50?mol%. The mechanical properties of the fibres were found to significantly increase with increasing B2O3 content. The highest tensile strength (1200?±?130?MPa) was recorded for 45P2O5-16CaO-5Na2O-24MgO-10B2O3 glass fibres. The fibres were annealed, and a comparison of the mechanical properties and mode of degradation of annealed and non-annealed fibres were investigated. A decrease in tensile strength and an increase in tensile modulus were observed for the annealed fibres. An assessment of the change in mechanical properties of both the annealed and non-annealed fibres was performed in phosphate-buffered saline (PBS) at 37? for 28 and 60 days, respectively. Initial loss of mechanical properties due to annealing was found to be recovered with degradation. The B2O3-containing glass fibres were found to degrade at a much slower rate as compared to the non-B2O3-containing fibres. Both annealed and non-annealed fibres exhibited a peeling effect of the fibre's outer layer during degradation. PMID:24939962

Sharmin, Nusrat; Parsons, Andrew J; Rudd, Chris D

2014-01-01

149

Original article Fibre type differentiation during postnatal  

E-print Network

between mus- cle fibres are usually found towards the end of fetal development. The fetal myofibres (orOriginal article Fibre type differentiation during postnatal development of miniature pig skeletal from 80 d of gestation to 1 year of age. Two fetal myofibre types were distinguished at 100 d

Boyer, Edmond

150

Slow and fast light in optical fibres  

Microsoft Academic Search

The ubiquitous role of optical fibres in modern photonic systems has stimulated research to realize slow and fast light devices directly in this close-to-perfect transmission line. Recent progress in developing optically controlled delays in optical fibres, operating under normal environmental conditions and at telecommunication wavelengths, has paved the way towards real applications for slow and fast light. This review presents

Luc Thévenaz

2008-01-01

151

Blending of Jute with Different Natural Fibres  

Microsoft Academic Search

Cotton, jute, flax, ramie, hemp, sisal, manila hemp, wool, and silk are some of the major natural fibres, which are widely being used throughout the world. Apart from these, a large number of fibres grown in much smaller quantities in different parts of the world have local economic importance and are mostly consumed locally. Jute is the second most important

Gautam Basu; Alok Nath Roy

2008-01-01

152

Temperature dependent conductivity behaviour of polyaniline fibres  

Microsoft Academic Search

The emeraldine base forin of polyaniline (PANi), processed using a novel combination of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) and dichloroacetic acid (DCA) solvent, has been spun into fibres. Differences observed in the temperature dependent conductivity behaviour of the fibres and similar solvent cast films are related to the different processing techniques employed.

P. N. Adams; S. J. Pomfret; A. P. Monkman

1999-01-01

153

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. PMID:18562844

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

2008-01-01

154

Dietary fibre and coronary heart disease.  

PubMed

Intake of dietary fibres lowers plasma lipids. Fibres particularly soluble ones lower serum total cholesterol (TC) and serum low-density lipoprotein cholesterol (LDL-C) without significant alteration in serum high-density lipoprotein cholesterol (HDL-C) and triacylglyccrol (TG). Consequently, the incidence of atherosclerotic heart diseases is lower in those who take high dietary fibre. Persons taking diet rich in saturated fat and poor in dietary fibre is more prone to develop coronary artery diseases. Dietary fibres also lower TC: HDL-C and LDL-C: HDL-C ratios. Higher TC: HDL-C and LDL-C: HDL-C ratios are in favour of development and progression of atherosclerotic vascular diseases, a pioneer cause of myocardial infarction (MI). PMID:12395688

Mia, M A R; Siddiqui, M N I; Haque, M S; Islam, M N; Rukunzzaman, M; Deb, K

2002-07-01

155

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

156

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

157

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

158

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

159

Advances in processing routes for conductive polyaniline fibres  

Microsoft Academic Search

Fibres have been wet spun from a sulfonic acid doped polyaniline solution. The fibres are inherently electrically conductive with conductivities of 100 (±30) Scm?1. Hot drawing of the fibres to 00 % elongation leads to an approximately ten fold increase in the conductivity. Typical fibres have a Young's modulus of 0.2 GPa, and a tensile strength at break of 50

S. J. Pomfret; P. N. Adams; N. P. Comfort; A. P. Monkman

1999-01-01

160

Left ventricular fibre architecture in man.  

PubMed Central

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 right the corresponding figure was 90 degrees. The thickest part of the left ventricular wall was at the base. At the apex there was potential endo- and epicardial continuity. Left ventricular cavity shape departed significantly from any simple geometric figure, there being, consistently, regions of both positive and negative curvature on the diaphragmatic aspect. The presence of trabeculae caused considerable variation in wall thickness. Striking variation was found in the arrangement of subepicardial muscle fibres. Most pronounced was the contrast between the longitudinal arrangement of fibres observed on the oblique margin and the circumferential arrangement of those on the acute. On the diaphragmatic surface of the left ventricle, fibres near the crux and apex ran circumferentially while those between ran obliquely; those on the diaphragmatic surface of the right ventricle also ran circumferentially. Deeper in the myocardium the arrangement was simpler. In the mid-wall of the left ventricle fibres were circumferential, best developed towards the base and in the upper part of the septum. Near the apex of the left ventricle and in the mid-wall of the right ventricle such fibres were sparse. The subendocardial region consisted of longitudinally directed fibres forming the trabeculae and papillary muscles, while fibres deep to and between the trabeculae coursed more obliquely. These findings were confirmed by histology. Models based on uniform myocardial fibre structure cannot explain wall movement in normal subjects, and are likely to have significant limitations if used to investigated left ventricular function in disease. Images PMID:7008815

Greenbaum, R A; Ho, S Y; Gibson, D G; Becker, A E; Anderson, R H

1981-01-01

161

Comptes Rendus des JNC 17 -Poitiers 2011 Comportement mcanique de btons rfractaires fibrs  

E-print Network

carbure de silicium. Trois types de renforcement sont considérés: des fibres en acier, des fibres de verre of this study is to quantify and to understand the effect of a steel and/or mineral fibre reinforcement: steel fibres, glass fibres and a mix of the two types of fibre. Results show that fibres have benefit

Paris-Sud XI, Université de

162

Effect of degumming time on silkworm silk fibre for biodegradable polymer composites  

NASA Astrophysics Data System (ADS)

Recently, many studies have been conducted on exploitation of natural materials for modern product development and bioengineering applications. Apart from plant-based materials (such as sisal, hemp, jute, bamboo and palm fibre), animal-based fibre is a kind of sustainable natural materials for making novel composites. Silkworm silk fibre extracted from cocoon has been well recognized as a promising material for bio-medical engineering applications because of its superior mechanical and bioresorbable properties. However, when producing silk fibre reinforced biodegradable/bioresorbable polymer composites, hydrophilic sericin has been found to cause poor interfacial bonding with most polymers and thus, it results in affecting the resultant properties of the composites. Besides, sericin layers on fibroin surface may also cause an adverse effect towards biocompatibility and hypersensitivity to silk for implant applications. Therefore, a proper pre-treatment should be done for sericin removal. Degumming is a surface modification process which allows a wide control of the silk fibre's properties, making the silk fibre possible to be used for the development and production of novel bio-composites with unique/specific mechanical and biodegradable properties. In this paper, a cleaner and environmentally friendly surface modification technique for tussah silk in polymer based composites is proposed. The effectiveness of different degumming parameters including degumming time and temperature on tussah silk is discussed through the analyses of their mechanical and morphological properties. Based on results obtained, it was found that the mechanical properties of tussah silk are affected by the degumming time due to the change of the fibre structure and fibroin alignment.

Ho, Mei-po; Wang, Hao; Lau, Kin-tak

2012-02-01

163

Red algae fibre\\/poly(butylene succinate) biocomposites: The effect of fibre content on their mechanical and thermal properties  

Microsoft Academic Search

The red algae (Gelidium Elegance) fibre was examined as a reinforcement of biocomposite. The extracting and bleaching process of the fibre from red algae were effective for both removal of mucilage materials and fiberization of red algae fibre. The bleached red algae fibre (BRAF) showed very similar crystallinity to the cellulose and also higher thermal stability with the maximum thermal

Min Woo Lee; Seong Ok Han; Yung Bum Seo

2008-01-01

164

Composite of short coir fibres and natural rubber: effect of chemical modification, loading and orientation of fibre  

Microsoft Academic Search

Coir fibre is considered to be a poor reinforcing fibre in rubber because of its low strength and lack of physical characteristics that are essential for a reinforcing fibre. Interfacial adhesion between coir and natural rubber (NR) was improved by treatment of the coir fibres with alkali (sodium hydroxide and sodium carbonate) and NR solution, and by the incorporation of

V. G. Geethamma; K. Thomas Mathew; R. Lakshminarayanan; Sabu Thomas

1998-01-01

165

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

166

The effects of MFA quota elimination on Indian fibre markets  

Microsoft Academic Search

This article examines the effects of multi-fibre arrangement (MFA) quota elimination on Indian fibre market. The partial equilibrium Indian fibre model was developed using a theoretically consistent framework and incorporated regional supply response, substitutability between cotton and man-made fibres, and appropriate linkage between cotton and textile sectors. Baseline projections were developed for supply, demand and prices of cotton, man-made fibres

Jagadanand Chaudhary; Samarendu Mohanty; Sukant Misra; Suwen Pan

2008-01-01

167

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

168

Low Cost Carbon Fibre for Automotive Applications Part 1: Low Cost Carbon Fibre Development  

SciTech Connect

In pursuit of the goal to produce ultra-lightweight fuel efficient vehicles, there has been great excitement during the last few years about the potential for using carbon fibre reinforced composites in high volume applications. Currently, the greatest hurdle that inhibits wider implementation of carbon fibre composites in transportation is the high cost of carbon fibre when compared to other candidate materials. However, significant research is being conducted to develop lower cost, high volume technologies for producing carbon fibre. This chapter will highlight ongoing research in this area.

Warren, Charles David [ORNL; Das, Sujit [ORNL; Wheatley, Dr. Alan [University of Sunderland

2014-01-01

169

Short communication FibreBags vs. FibreCaps for acid  

E-print Network

fibre / sainfoin, Onobrychis viciifolia / birdsfoot trefoil, Lotus corniculatus 1. INTRODUCTION for this evalu- ation: birdsfoot trefoil (Lotus cornicultus L.), sainfoin (Onobrychis viciifolia Scop.), red

Paris-Sud XI, Université de

170

Fibre Bundles and G-Structures  

NASA Astrophysics Data System (ADS)

In this appendix, we shall recapitulate a few key definitions and results from the theory of fibre bundles and G-structures. We shall define G-structures using the concept of coordinate transformations on the base space with values in a group, which was made an integral part of his definition of fibre bundles by Steenrod [102]. Fibre bundles enjoy a crucial property known as the homotopy lifting property (the covering homotopy theorems; [102], Sect. 11), and in topological applications it is often this property that is essential. Accordingly, in the topological literature one often comes across definitions of fibre bundles that do not refer to coordinate transformations on the base space with values in a group, but in geometry one has to ask for more.

Borchers, Hans-Jürgen; Sen, Rathindra Nath

171

Optical Fibre Angle Sensor Used in MEMS  

NASA Astrophysics Data System (ADS)

There is a need for displacement and angle measurements in many movable MEMS structures. The use of fibre optical sensors helps to measure micrometre displacements and small rotation angles. Advantages of this type of transducers are their simple design, high precision of processing, low costs and ability of a non-contact measurement. The study shows an analysis of a fibre-optic intensity sensor used for MEMS movable structure rotation angle measurement. An intensity of the light in the photodetector is basically dependent on a distance between a reflecting surface and a head surface of the fibre transmitting arm, and the deflection angle. Experimental tests were made for PMMA 980/1000 plastic fibres, ?NA=33°. The study shows both analytical and practical results. It proves that calculated and experimental characteristics for the analysed transducers are similar.

Golebiowski, J.; Milcarz, Sz; Rybak, M.

2014-04-01

172

Angiogenic effect induced by mineral fibres.  

PubMed

Due to the toxic effect of asbestos, other materials with similar chemical-physical characteristics have been introduced to substitute it. We evaluate the angiogenic effect of certain asbestos substitute fibres such as glass fibres (GFs), ceramic fibres (CFs) and wollastonite fibres (WFs) and then compare angiogenic responses to those induced by crocidolite asbestos fibres (AFs). An in vitro model using human endothelial cells in small islands within a culture matrix of fibroblasts (Angio-Kit) was used to evaluate vessel formation. The release of IL-6, sIL-R6, IL-8, VEGF-A and their soluble receptors, sVEGFR-1, sVEGFR-2, was determined in the conditioning medium of Angio-Kit system after fibre treatment. ROS formation and cell viability were evaluated in cultured endothelial cells (HUVEC). To evaluate the involvement of intracellular mechanisms, EGFR signalling, ROS formation and nuclear factor-?B (NF?B) pathway were then inhibited by incubating HUVEC cells with AG1478, NAC and PDTC respectively, and the cytokine and growth factor release was analyzed in the culture medium after 7 days of fibre incubation. Among the mineral fibres tested, WFs markedly induced blood vessel formation which was associated with release of IL-6 and IL-8, VEGF-A and their soluble receptors. ROS production was observed in HUVEC after WFs treatment which was associated with cell cytotoxicity. The EGFR-induced ERK phosphorylation and ROS-mediated NF?B activation were involved in the cytokine and angiogenic factor release. However, only the EGFR activation was able to induce angiogenesis. The WFs are potential angiogenic agents that can induce regenerative cytokine and angiogenic factor production resulting in the formation of new blood vessels. PMID:21762757

Carbonari, Damiano; Campopiano, Antonella; Ramires, Deborah; Strafella, Elisabetta; Staffolani, Sara; Tomasetti, Marco; Curini, Roberta; Valentino, Matteo; Santarelli, Lory; Amati, Monica

2011-10-01

173

Simulating Fibre Suspensions: Lagrangian versus Statistical Approach  

NASA Astrophysics Data System (ADS)

Fibre suspensions exhibit complex dynamical flow phenomena and are at the same time of immense practical importance, notably in the pulp and paper industries. NTNU and TU Delft have in a collaborative research project adopted two alternative strategies in the simulation of dilute fibre suspensions, namely a statistical approach [2] and a Lagrangian particle treatment [4]. The two approaches have their own advantages and disadvantages. In this paper we aim for the first time to compare the performance of the two.

Zhao, L. H.; Andersson, H. I.; Gillissen, J. J. J.; Boersma, B. J.

174

Fibre-based post systems: a review  

Microsoft Academic Search

Objectives This article presents a review of published literature examining fibre-based endodontic post systems.Data sources A MEDLINE search was carried out for any articles in dental journals pertaining to fibre-based post systems. Wherever possible articles cited were obtained from the journals and where this was not possible abstracts were obtained. Where no abstract was available the article was not considered

D N J Ricketts; W P Saunders; G Bateman

2003-01-01

175

The Properties Of The Samarium Fibre Laser  

NASA Astrophysics Data System (ADS)

The optical properties of trivalent Samarium doped silica glass fibres are described. This material has a narrow fluorescence of 2.2 nm f.w.h.m. at a wavelength of 650 nm. Visible laser emission is obtained at this wavelength when the fibre is pumped in a Fabry Perot cavity. The performance of the laser in continuous, Q-switched and self mode-locked operation is described.

Farries, Mark C.; Morkel, Paul R.; Townsend, Janet E.

1990-02-01

176

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

177

Fibre-optic sensors in health care  

NASA Astrophysics Data System (ADS)

Biomedical fibre-optic sensors are attractive for the measurement of physical, chemical and biochemical parameters and for spectral measurements directly performed on the patient. An overview of fibre-optic sensors for in vivo monitoring is given, with particular attention paid to the advantages that these sensors are able to offer in different application fields such as cardiovascular and intensive care, angiology, gastroenterology, ophthalmology, oncology, neurology, dermatology and dentistry.

Grazia Mignani, Anna; Baldini, Francesco

1997-05-01

178

Photonic crystal fibres in biomedical investigations  

SciTech Connect

The state of the art in the field of design and study of photonic crystal fibres for biomedical applications is considered and some original results recently obtained by the authors are presented. Optical properties of the fibres that offer prospects of their wide application as biological sensors, 'labs-on-a-chip', and facilities of electromagnetic radiation control in a wide range of wavelengths aimed at designing novel biomedical instrumentation are considered (optical technologies in biophysics and medicine)

Skibina, Yu S; Tuchin, Valerii V; Beloglazov, V I; Shteinmaeer, G; Betge, I L; Wedell, R; Langhoff, N

2011-04-30

179

Dietary fibre in foods: a review  

Microsoft Academic Search

Dietary fibre is that part of plant material in the diet which is resistant to enzymatic digestion which includes cellulose,\\u000a noncellulosic polysaccharides such as hemicellulose, pectic substances, gums, mucilages and a non-carbohydrate component lignin.\\u000a The diets rich in fibre such as cereals, nuts, fruits and vegetables have a positive effect on health since their consumption\\u000a has been related to decreased

Devinder Dhingra; Mona Michael; Hradesh Rajput; R. T. Patil

180

Reinforcing of Cement Composites by Estabragh Fibres  

NASA Astrophysics Data System (ADS)

The influence of Estabragh fibres has been studied to improve the performance characteristics of the reinforced cement composites. The concrete shrinkage was evaluated by counting the number of cracks and measuring the width of cracks on the surface of concrete specimens. Although, the Estabragh fibres lose their strength in an alkali environment of cement composites, but, the ability of Estabragh fibres to bridge on the micro cracks in the concrete matrix causes to decrease the width of the cracks on the surface of the concrete samples in comparison with the plain concrete. However, considering the mechanical properties of specimens such as bending strength and impact resistance, the specimens with 0.25 % of Estabragh fibre performed better in all respects compared to the physical and mechanical properties of reinforced cement composite of concrete. Consequently, by adding 0.25 % of Estabragh fibres to the cement composite of concrete, a remarkable improvement in physical and mechanical properties of fibre-containing cement composite is achieved.

Merati, A. A.

2014-04-01

181

Fibre positioning algorithms for the WEAVE spectrograph  

NASA Astrophysics Data System (ADS)

WEAVE is the next-generation wide-field optical spectroscopy facility for the William Herschel Telescope (WHT) in La Palma, Canary Islands, Spain. It is a multi-object "pick and place" fibre fed spectrograph with more than one thousand fibres, similar in concept to the Australian Astronomical Observatory's 2dF1 instrument with two observing plates, one of which is observing the sky while other is being reconfigured by a robotic fibre positioner. It will be capable of acquiring more than 10000 star or galaxy spectra a night. The WEAVE positioner concept uses two robots working in tandem in order to reconfigure a fully populated field within the expected 1 hour dwell-time for the instrument (a good match between the required exposure times and the limit of validity for a given configuration due to the effects of differential refraction). This presents additional constraints and complications for the software that determines the optimal path from one configuration to the next, particularly given the large number of fibre crossings implied by the 1000 fibre multiplex. This paper describes the algorithms and programming techniques used in the prototype implementations of the field configuration tool and the fibre positioner robot controller developed to support the detailed design of WEAVE.

Terrett, David L.; Lewis, Ian J.; Dalton, Gavin; Abrams, Don Carlos; Aguerri, J. Alfonso L.; Bonifacio, Piercarlo; Middleton, Kevin; Trager, Scott C.

2014-07-01

182

Low-coherence optical fibre speckle interferometry  

NASA Astrophysics Data System (ADS)

This paper describes the development of optical fibre low-coherence speckle interferometers capable of three-dimensional surface profiling with a resolution of 10-20 µm and a depth range of typically tens of centimetres. The technique is absolute, enabling the measurement of steps and through holes. The inclusion of optical fibres enables compact, flexible configurations to be realized, alleviating the experimental difficulties encountered with bulk interferometers, particularly when using long path lengths for measurements on large test objects. Sources including light-emitting and superluminescent diodes and multimode laser diodes are compared, and the use of a multimode laser diode source in pulsed mode is shown to improve depth resolution. Fibre-based systems using both single mode and polarization-maintaining fibre are described, and the results of experimental measurements on a stepped test object, a tilted plate and a coin are presented. A depth resolution of ±20 µm is obtained for the standard fibre system and ±14 µm for the system based on polarization-maintaining fibre.

Balboa, I.; Ford, H. D.; Tatam, R. P.

2006-04-01

183

Dietary fibres and ovarian cancer risk.  

PubMed

Data from an Italian multicentre case-control study on ovarian cancer were used to analyse the relationship between various types of fibres and ovarian cancer risk. The study, conducted between 1992 and 1999, included 1031 cases of incident, histologically-confirmed epithelial ovarian cancer. Controls were 2411 women admitted to the same network of hospitals for acute, non-malignant, non-hormonal-related diseases. Cases and controls were interviewed using a validated food frequency questionnaire (FFQ). Odds ratios (ORs), and the corresponding 95% confidence intervals (CI), were estimated using unconditional multiple logistic regression models. For total (Englyst) fibre, the OR for the highest versus the lowest quintile of intake was 0.68, and the continuous OR for the difference between the 80th and the 20th percentile of intake was 0.87. For most types of fibre, the continuous OR was significantly below 1. The OR was 0.83 for cellulose, 0.89 for soluble non-cellulose polysaccharides (NCPs), 0.86 for total insoluble fibre, 0.92 for insoluble NCP, and 0.95 (non-significant) for lignin. The inverse association was consistent across strata of age, family history and menopausal status, even if the association was apparently stronger in postmenopausal women. When fibre was classified according to the source, vegetable (but not grain) fibres, showed a significant protective effect, with an OR of 0.78. PMID:11677113

Pelucchi, C; La Vecchia, C; Chatenoud, L; Negri, E; Conti, E; Montella, M; Calza, S; Dal Maso, L; Franceschi, S

2001-11-01

184

The role of matrix cracks and fibre\\/matrix debonding on the stress transfer between fibre and matrix in a single fibre fragmentation test  

Microsoft Academic Search

The single fibre fragmentation test is commonly used to characterise the fibre\\/matrix interface. During fragmentation, the stored energy is released resulting in matrix cracking and\\/or fibre\\/matrix debonding.Axisymmetric finite element models were formulated to study the impact of matrix cracks and fibre\\/matrix debonding on the effective stress transfer efficiency (EST) and stress transfer length (STL). At high strains, plastic deformation in

Anbu Clemensis Johnson; Simon A. Hayes; Frank R. Jones

185

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

Microsoft Academic Search

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%. Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Abstract Text Return: Query Results Return items starting with number Query Form

Andrei S. Kurkov; V. I. Karpov; A. Yu Laptev; O. I. Medvedkov; Evgenii M. Dianov; A. N. Gur'yanov; Sergei A. Vasil'ev; Vladimir M. Paramonov; V. N. Protopopov; A. A. Umnikov; N. I. Vechkanov; V. G. Artyushenko; J. Frahm

1999-01-01

186

Development of high-power holmium-doped fibre amplifiers  

NASA Astrophysics Data System (ADS)

Resonantly pumped holmium fibre lasers present a range of opportunities for the development of novel fibre laser and amplifier devices due to the availability of mature, efficient high power thulium fibre pump lasers. In this paper we describe the operation of a large mode area holmium-doped fibre amplifier. The master-oscillator is an all-fibre linearly polarised, core pumped single mode laser operating at 27 W at 2.11 ?m. This laser was amplified in a large mode area fibre producing up to 265 W of output power. This system is the first demonstration of a resonantly pumped holmiumdoped fibre amplifier. It is also the highest power fibre amplifier that is capable of operating in an atmospheric transmission window <2.05 ?m. This monolithic all-fibre system is able to address a wide range of remote sensing, scientific, medical and defence applications.

Hemming, Alexander; Simakov, Nikita; Davidson, Alan; Oermann, Michael; Corena, Len; Stepanov, Dmitrii; Carmody, Neil; Haub, John; Swain, Robert; Carter, Adrian

2014-03-01

187

Properties of Wood Fibre-Polypropylene Composites: Effect of Wood Fibre Source  

NASA Astrophysics Data System (ADS)

This study examined the effect of type of wood fibre source on the physical and mechanical properties of wood fibre-polypropylene composites. Wood flour, fibres of heat-treated wood and pellets were used as sources of wood fibres in the manufacturing process. All studied wood fibre-polypropylene composites were made from 75% wood, 22% recycled polypropylene (PP) and 3% maleated polypropylene (MAPP). Wood fibre-polypropylene composites were compounded in a conical twin-screw extruder. Water absorption and thickness swelling were studied. Mechanical properties of the composites were characterised by tensile, flexural, and impact testing. Micromechanical deformation processes were investigated using scanning electron microscopy done on the fractured surfaces of broken samples. The durability of composites exposed to three accelerated cycles of water immersion, freezing and thawing was examined. The results showed that the density of the composites was a key factor governing water absorption and thickness swelling. A significant improvement in tensile strength, flexural strength, and Charpy impact strength was observed for composites reinforced with heat-treated fibre compared to composites reinforced with pellets and especially to wood flour reinforced composites. The flexural strength and dimensional stability performance reduced after exposure to freeze-thaw cycling for all composites, but the degree of these changes was dependent on the wood fibre source.

Butylina, Svetlana; Martikka, Ossi; Kärki, Timo

2011-04-01

188

Corneal confocal microscopy: a novel means to detect nerve fibre damage in idiopathic small fibre neuropathy.  

PubMed

Patients with idiopathic small fibre neuropathy (ISFN) have been shown to have significant intraepidermal nerve fibre loss and an increased prevalence of impaired glucose tolerance (IGT). It has been suggested that the dysglycemia of IGT and additional metabolic risk factors may contribute to small nerve fibre damage in these patients. Twenty-five patients with ISFN and 12 aged-matched control subjects underwent a detailed evaluation of neuropathic symptoms, neurological deficits (Neuropathy deficit score (NDS); Nerve Conduction Studies (NCS); Quantitative Sensory Testing (QST) and Corneal Confocal Microscopy (CCM)) to quantify small nerve fibre pathology. Eight (32%) patients had IGT. Whilst all patients with ISFN had significant neuropathic symptoms, NDS, NCS and QST except for warm thresholds were normal. Corneal sensitivity was reduced and CCM demonstrated a significant reduction in corneal nerve fibre density (NFD) (P<0.0001), nerve branch density (NBD) (P<0.0001), nerve fibre length (NFL) (P<0.0001) and an increase in nerve fibre tortuosity (NFT) (P<0.0001). However these parameters did not differ between ISFN patients with and without IGT, nor did they correlate with BMI, lipids and blood pressure. Corneal confocal microscopy provides a sensitive non-invasive means to detect small nerve fibre damage in patients with ISFN and metabolic abnormalities do not relate to nerve damage. PMID:19748505

Tavakoli, Mitra; Marshall, Andrew; Pitceathly, Robert; Fadavi, Hassan; Gow, David; Roberts, Mark E; Efron, Nathan; Boulton, Andrew Jm; Malik, Rayaz A

2010-05-01

189

A flax fibre proteome: identification of proteins enriched in bast fibres  

Microsoft Academic Search

BACKGROUND: Bast fibres from the phloem tissues of flax are scientifically interesting and economically useful due in part to a dynamic system of secondary cell wall deposition. To better understand the molecular mechanisms underlying the process of cell wall development in flax, we extracted proteins from individually dissected phloem fibres (i.e. individual cells) at an early stage of secondary cell

Naomi SC Hotte; Michael K Deyholos

2008-01-01

190

Inventory of World Fibres and Involvement of FAO in Fibre Research  

Microsoft Academic Search

Linen and hemp fabrics are among the oldest in the world; their history goes back to ca 8000 BC. In Central Europe, among the most notable discoveries of Polish archaeologists were linen textiles and fibres dating from 4000 BC, i.e. from the period known in archaeology as the Neolithic Age. The fibres were used not only for textile applications but

Ryszard Kozlowski; Maria Mackiewicz-Talarczyk

2000-01-01

191

Comparison of Enzymatically Separated Hemp and Nettle Fibre to Chemically Separated and Steam Exploded Hemp Fibre  

Microsoft Academic Search

Hemp (Cannabis sativaL.) and nettle (Urtica dioicaL.) are both attractive candidates for high fibre yields with little or no biocide requirement. Separation of fibre fine enough for quality yarns to make hemp fabric or blends has been achieved in Western Europe in the last decades only on a laboratory scale because process costs are high. In Hungary, Romania, the Ukraine

J. Dreyer; J. Müssig; N. Koschke; W.-D. Ibenthal; H. Harig

2002-01-01

192

A flax fibre proteome: identification of proteins enriched in bast fibres  

PubMed Central

Background Bast fibres from the phloem tissues of flax are scientifically interesting and economically useful due in part to a dynamic system of secondary cell wall deposition. To better understand the molecular mechanisms underlying the process of cell wall development in flax, we extracted proteins from individually dissected phloem fibres (i.e. individual cells) at an early stage of secondary cell wall development, and compared these extracts to protein extracts from surrounding, non-fibre cells of the cortex, using fluorescent (DiGE) labels and 2D-gel electrophoresis, with identities assigned to some proteins by mass spectrometry. Results The abundance of many proteins in fibres was notably different from the surrounding non-fibre cells of the cortex, with approximately 13% of the 1,850 detectable spots being significantly (> 1.5 fold, p ? 0.05) enriched in fibres. Following mass spectrometry, we assigned identity to 114 spots, of which 51 were significantly enriched in fibres. We observed that a K+ channel subunit, annexins, porins, secretory pathway components, ?-amylase, ?-galactosidase and pectin and galactan biosynthetic enzymes were among the most highly enriched proteins detected in developing flax fibres, with many of these proteins showing electrophoretic patterns consistent with post-translational modifications. Conclusion The fibre-enriched proteins we identified are consistent with the dynamic process of secondary wall deposition previously suggested by histological and biochemical analyses, and particularly the importance of galactans and the secretory pathway in this process. The apparent abundance of ?-amylase suggests that starch may be an unappreciated source of materials for cell wall biogenesis in flax bast fibres. Furthermore, our observations confirm previous reports that correlate accumulation proteins such as annexins, and specific heat shock proteins with secondary cell wall deposition. PMID:18447950

Hotte, Naomi SC; Deyholos, Michael K

2008-01-01

193

Microstructure characterization of erosion resistant coatings on carbon-bonded carbon fibre composites.  

PubMed

The microstructure of as received and surface treated carbon-bonded carbon fibre composites has been examined by light microscopy, scanning and transmission electron microscopy. The microstructure of the as received material consists of a bonded together layered carbon fiber network, identified as graphitic carbon (hexagonal close packed). To improve the erosion resistance of the carbon-bonded carbon fibre composites composite, the SiC and silicate glass-ceramic coatings from the system SiO(2)-Al(2)O(3)-Y(2)O(3) were produced on carbon-bonded carbon fibre composites composites by a low-cost slurry technique. Transmission electron microscopy investigations of cross-section thin foils allowed for detailed analysis of the coatings microstructure. It was found that the SiC coating was consisting mainly of a nanocrystalline SiC (fcc). The multilayered glass-ceramic coating showed a complex microstructure consisting of an external SiO(2)-Al(2)O(3)-Y(2)O(3) layer and an intermediate nanocrystalline SiC layer. The SiO(2)-Al(2)O(3)-Y(2)O(3) layer was composed of SiO(2) (fcc), Y(2)Si(2)O(7) (op) and Al(4.644)Si(1.357)O(9.68) (op). PMID:20500382

Moskalewicz, T; Smeacetto, F; Salvo, M; Boccaccini, A R; Czyrska-Filemonowicz, A

2010-03-01

194

Does Optic Nerve Head Surface Topography Change Prior to Loss of Retinal Nerve Fiber Layer Thickness: A Test of the Site of Injury Hypothesis in Experimental Glaucoma  

PubMed Central

Purpose To test the hypothesis that optic nerve head (ONH) deformation manifesting as changes in its mean surface height precedes thinning of the peripapillary retinal nerve fiber layer (RNFL) in experimental glaucoma (EG). Methods 68 rhesus macaque monkeys each had three or more baseline imaging sessions under manometric intraocular pressure (IOP) control to obtain average RNFL thickness (RNFLT) and the ONH surface topography parameter mean position of the disc (MPD). Laser photocoagulation was then applied to the trabecular meshwork of one eye to induce chronic, mild-to-moderate IOP elevation and bi-weekly imaging continued. Event analysis was applied to determine for each parameter when an ‘endpoint’ occurred (signficant change from baseline) for eight different endpoint criteria. Specificity was assessed in the group of 68 fellow control eyes. Classical signal detection theory and survival analysis were used to compare MPD with RNFLT. Results Regardless of the endpoint criterion, endpoints were always more frequent for MPD than for RNFLT. The discriminability index (d’) was 2.7 ± 0.2 for MPD and 1.9 ± 0.2 for RNFLT (p<0.0001). Endpoints were reached by MPD an average of 1-2 months earlier than by RNFLT (p<0.01). At the onset of the first specific, detectable MPD change in EG eyes, there was still no significant change in RNFLT on average (p=0.29) and only 25% of individual eyes exhibited signficant reduction. In contrast, at onset of signficant RNFLT change, MPD had already changed an average of 101 µm from baseline (p<0.0001) and 71% of the individual eyes had exhibited significant change. The magnitude of MPD change was more than could be explained on the basis of axon loss alone. Conclusions This study demonstrates that the average surface height of the ONH changes prior to any detectable loss of average peripapillary RNFL thickness in non-human primate eyes with experimental glaucoma. PMID:24204989

Fortune, Brad; Reynaud, Juan; Wang, Lin; Burgoyne, Claude F.

2013-01-01

195

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. PMID:24083087

Ledolter, Johannes; Kardon, Randy

2013-01-01

196

Microarray Analysis of Developing Flax Hypocotyls Identifies Novel Transcripts Correlated with Specific Stages of Phloem Fibre Differentiation  

PubMed Central

Background and Aims Hypocotyls are a commonly used model to study primary growth in plants, since post-germinative hypocotyls increase in size by cell elongation rather than cell division. Flax hypocotyls produce phloem fibres in bundles one to two cell layers thick, parallel to the protoxylem poles of the stele. Cell wall deposition within these cells occurs rapidly at a well-defined stage of development. The aim was to identify transcripts associated with distinct stages of hypocotyl and phloem fibre development. Methods Stages of flax hypocotyl development were defined by analysing hypocotyl length in relation to fibre secondary wall deposition. Selected stages of development were used in microarray analyses to identify transcripts involved in the transition from elongation to secondary cell wall deposition in fibres. Expression of specific genes was confirmed by qRT-PCR and by enzymatic assays. Key Results Genes enriched in the elongation phase included transcripts related to cell-wall modification or primary-wall deposition. Transcripts specifically enriched at the transition between elongation and secondary wall deposition included ?-galactosidase and arabinogalactan proteins. Later stages of wall development showed an increase in secondary metabolism-related transcripts, chitinases and glycosyl hydrolases including KORRIGAN. Microarray analysis also identified groups of transcription factors enriched at one or more stages of fibre development. Subsequent analysis of a differentially expressed ?-galactosidase confirmed that the post-elongation increase in ?-galactosidase enzyme activity was localized to phloem fibres. Conclusions Transcripts were identified associated with specific stages of hypocotyl development, in which phloem fibre cells were undergoing thickening of secondary walls. Temporal and spatial regulation of ?-galactosidase activity suggests a role for this enzyme in remodelling of flax bast fibre cell walls during secondary cell wall deposition. PMID:18593690

Roach, Melissa J.; Deyholos, Michael K.

2008-01-01

197

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

198

Nonlinear optics of fibre event horizons  

NASA Astrophysics Data System (ADS)

The nonlinear interaction of light in an optical fibre can mimic the physics at an event horizon. This analogue arises when a weak probe wave is unable to pass through an intense soliton, despite propagating at a different velocity. To date, these dynamics have been described in the time domain in terms of a soliton-induced refractive index barrier that modifies the velocity of the probe. Here we complete the physical description of fibre-optic event horizons by presenting a full frequency-domain description in terms of cascaded four-wave mixing between discrete single-frequency fields, and experimentally demonstrate signature frequency shifts using continuous wave lasers. Our description is confirmed by the remarkable agreement with experiments performed in the continuum limit, reached using ultrafast lasers. We anticipate that clarifying the description of fibre event horizons will significantly impact on the description of horizon dynamics and soliton interactions in photonics and other systems.

Webb, Karen E.; Erkintalo, Miro; Xu, Yiqing; Broderick, Neil G. R.; Dudley, John M.; Genty, Goëry; Murdoch, Stuart G.

2014-09-01

199

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. PMID:24098838

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

2012-01-01

200

On the topology of chromatin fibres.  

PubMed

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. PMID:24098838

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

2012-10-01

201

Nanostructured fibre tip for trapping of nanoparticles  

NASA Astrophysics Data System (ADS)

We propose to optically trap nanoparticles utilizing a single nanostructured glass-fiber tip. 3D translation of optically trapped nanoparticles - nano tweezers - presents vast application possibilities and has not yet been shown. The input end of the fibre probe is a standard fibre, providing easy coupling to a light source. The output end is tapered down and covered with gold, with a nanoaperture fabricated on the tip. The nanoaperture provides the strong field gradient necessary for trapping of nanoparticles. We discuss probe geometries supported by numerical simulations. The fabrication procedure for the fibre probe, using a focused ion beam, is described. A set-up for the experiments has been made and preliminary trapping results are presented.

Tinguely, Jean-Claude; Ding, Ming; Brambilla, Gilberto; Hohenau, Andreas; Krenn, Joachim R.; Hellesø, Olav G.

2014-02-01

202

Nonlinear optics of fibre event horizons  

E-print Network

The nonlinear interaction of light in an optical fibre can mimic the physics at an event horizon. This analogue arises when a weak probe wave is unable to pass through an intense soliton, despite propagating at a different velocity. To date, these dynamics have been described in the time domain in terms of a soliton-induced refractive index barrier that modifies the velocity of the probe. Here, we complete the physical description of fibre-optic event horizons by presenting a full frequency-domain description in terms of cascaded four-wave mixing between discrete single-frequency fields, and experimentally demonstrate signature frequency shifts using continuous wave lasers. Our description is confirmed by the remarkable agreement with experiments performed in the continuum limit, reached using ultrafast lasers. We anticipate that clarifying the description of fibre event horizons will significantly impact on the description of horizon dynamics and soliton interactions in photonics and other systems.

Webb, Karen E; Xu, Yiqing; Broderick, Neil G R; Dudley, John M; Genty, Goery; Murdoch, Stuart G

2014-01-01

203

Extracellular potentials of single active muscle fibres: effects of finite fibre length.  

PubMed

The extracellular action potentials (ECAPs) of single active muscle fibres immersed an isotropic volume conductor were investigated. The origination of excitation in the motor end-plate and its reaching the fibre end were taken into consideration. It was explained why at short radial distances the ECAPs over the fibre at points close to the end were similar in shape to the first time derivative and at points close to the motor end-plate - to the first time derivative of the intracellular action potential (ICAP) taken with minus sign. The fibre end changed the ECAP which would be recorded if the fibre was infinite and this change called pure termination potential (PTP) was a biphase positive-negative potential, proportional to the first time derivative of the ICAP at points close to the membrane and over the very end. With increasing the radial and axial distances PTP decreases in amplitude. Taking into account the PTP, the genesis of the terminal positive phase of the ECAPs (Gydikov and Kosarov 1972a, b) can be explained. The onset of the fibre or the motor end-plate also changed the potential which would be recorded if the fibre was infinite. This change was given the term of pure onset potential (POP) - a biphase negative-positive potential, proportional to the first time derivative of the ICAP taken with minus sign at a point close to the membrane and over the motor end-plate. With increasing the radial and the axial distance POP decreased in amplitude. Close to the membrane PTP and POP were commensurable with the potential of an infinite fibre only at points close to the ends or to the motor end-plate. At long radial distances they were commensurable with the potential of an infinite fibre for all axial distances. PMID:3697406

Gydikov, A A; Trayanova, N A

1986-01-01

204

Microfibrils, elastin fibres and collagen fibres in the human intervertebral disc and bovine tail disc  

PubMed Central

The distribution of microfibrils was studied immunohistochemically in intervertebral discs taken from young normal human surgical cases and from the bovine tail. Co-localization of microfibrils and elastin fibres was examined by dual immunostaining of fibrillin-1 and elastin. Collagen fibre network orientation was studied by using polarized filters. A similar microfibrillar network was seen in both bovine and human discs with network organization being completely different from region to region. In the outer annulus fibrosus (OAF), abundant microfibrils organized in bundles were mainly distributed in the interterritorial matrix. In addition, the microfibril bundles were orientated parallel to each other and co-localized highly with elastin fibres. Within each lamella, co-localized microfibrils and elastin fibres were aligned in the same direction as the collagen fibres. In the interlamellar space, a dense co-localized network, staining for both microfibrils and elastin fibres, was apparent; immunostaining for both molecules was noticeably stronger than within lamellae. In the inner annulus fibrosus, the microfibrils were predominantly visible as a filamentous mesh network, both in the interterritorial matrix and also around the cells. The microfibrils in this region co-localized with elastin fibres far less than in the OAF. In nucleus pulposus, filamentous microfibrils were organized mainly around the cells where elastin fibres were hardly detected. By contrast, sparse elastin fibres, with a few of microfibrils, were visible in the interterritorial matrix. The results of this study suggest the microfibrillar network of the annulus may play a mechanical role while that around the cells of the nucleus may be more involved in regulating cell function. PMID:17428205

Yu, Jing; Tirlapur, Uday; Fairbank, Jeremy; Handford, Penny; Roberts, Sally; Winlove, C Peter; Cui, Zhanfeng; Urban, Jill

2007-01-01

205

Formation of shock waves in inhomogeneous active fibres  

SciTech Connect

The formation dynamics of the shock wave of a pulse envelope is considered in fibres with the gain, dispersion, and nonlinearity distributed over the fibre length. It is shown that the wave-front steepness for inhomogeneous optical fibres can be strongly increased even when the local group-velocity dispersion substantially differs from zero if its average value (over the length of the shock-wave formation) is close to zero. (fibre optics)

Zolotovskii, Igor' O; Sementsov, Dmitrii I [Ul'yanovsk State University, Ul'yanovsk (Russian Federation)

2005-05-31

206

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

207

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

2011-06-01

208

OPTICAL FIBRES: Spun optical fibres: A helical structure of linear birefringence or circular birefringence?  

NASA Astrophysics Data System (ADS)

An experiment has been proposed, theoretically substantiated and accomplished which has provided conclusive evidence in favour of one of two models for the behaviour of polarised light in optical fibres fabricated by spinning preforms with a high built-in linear birefringence (spun fibres): a helical structure of the built-in linear birefringence axes and circular birefringence. The experiment, carried out with a reflective fibreoptic dual-polarisation interferometer, has shown that the behaviour of polarisation states in spun fibres can be understood in terms of a helical structure of the built-in linear birefringence axes.

Morshnev, Sergey K.; Gubin, Vladimir P.; Vorob'ev, I. P.; Starostin, I. I.; Sazonov, Aleksandr I.; Chamorovsky, Yury K.; Korotkov, N. M.

2009-03-01

209

A circle-based method for detection of neural fibre cross-sections in classically stained 2D electron  

E-print Network

reconstruction of even the smallest neural fibres by human experts. However, manual reconstruction; electron microscopy; neural circuit reconstruction; connectomics; ilastik I. INTRODUCTION Complete mapping. The micro-architecture of grey matter varies between brain areas. Here we focus on the molecular layer

Guillas, Serge

210

Highly strong and elastic graphene fibres prepared from universal graphene oxide precursors.  

PubMed

Graphene fibres are continuously prepared from universal graphene oxide precursors by a novel hydrogel-assisted spinning method. With assistance of a rolling process, meters of ribbon-like GFs, or GRs with improved conductivity, tensile strength, and a long-range ordered compact layer structure are successfully obtained. Furthermore, we refined our spinning process to obtained elastic GRs with a mixing microstructure and exceptional elasticity, which may provide a platform for electronic skins and wearable electronics, sensors, and energy devices. PMID:24576869

Huang, Guoji; Hou, Chengyi; Shao, Yuanlong; Wang, Hongzhi; Zhang, Qinghong; Li, Yaogang; Zhu, Meifang

2014-01-01

211

Capillary optical fibre sensor for measurement of dry weight in liquid sugar  

NASA Astrophysics Data System (ADS)

Miniaturization in technology of optical fiber sensors implies new areas of applications in the field of control of food fabrication. The paper presents new idea of capillary optical fibre sensor based on double layer capillary waveguide for dry weight in liquid sugar measurement. The mathematical analysis of sensor's construction is presented. The construction of sensor, its fabrication process and measurement results are shown. The paper also contains the experimental characteristic of elaborated sensor.

Miluski, Piotr

212

Highly Strong and Elastic Graphene Fibres Prepared from Universal Graphene Oxide Precursors  

PubMed Central

Graphene fibres are continuously prepared from universal graphene oxide precursors by a novel hydrogel-assisted spinning method. With assistance of a rolling process, meters of ribbon-like GFs, or GRs with improved conductivity, tensile strength, and a long-range ordered compact layer structure are successfully obtained. Furthermore, we refined our spinning process to obtained elastic GRs with a mixing microstructure and exceptional elasticity, which may provide a platform for electronic skins and wearable electronics, sensors, and energy devices. PMID:24576869

Huang, Guoji; Hou, Chengyi; Shao, Yuanlong; Wang, Hongzhi; Zhang, Qinghong; Li, Yaogang; Zhu, Meifang

2014-01-01

213

Hybrid yarn for thermoplastic fibre composites Publications Department  

E-print Network

Hybrid yarn for thermoplastic fibre composites Publications Department publications Hybrid yarn for thermoplastic fibre composites. Summary of technical results Final report for MUP2 Framework Program No. 1994:10:53 #12;Hybrid yarn for thermoplastic fibre composites. Introduction Publications Risø-R-1034 Hybrid yarn

214

Enzymatic Bioprocessing - New Tool of Extensive Natural Fibre Source Utilization  

Microsoft Academic Search

New enzymes are going to have great potential in bast fibre processing and modification for different end uses. There are several new technologies using enzymes able to modify fiber parametres, achieve desired properties, improve processing results and ecology in the area of bast fibre processing and fabric finishing. Enzymatic retting of flax, enzymatic cottonization of bast fibre, enzymatic hemp separation,

Marek Jan; Antonov Viktor; Bjelkova Marie; Smirous Prokop; Fischer Holger; Janosik Stefan

215

Performance of oil palm EFB fibre reinforced concrete roof slates  

Microsoft Academic Search

Natural fibres such as wood and vegetable fibre offer many advantages such as renewability, recyclability low specific gravity and high specific strength. In Malaysia most of the studies only focused on producing EFB as MDF and pulp and paper products. This paper reviews the development of natural fibres for building material and discusses the performance of oil palm empty fruit

J. Kaliwon; S. Sh Ahmad; A. Abdul Aziz

2010-01-01

216

Spectroscopic and morphological examination of polypropylene fibres modified with polyaniline  

Microsoft Academic Search

This paper presents the results of examining polypropylene fibres containing polyaniline (PANI) doped with dodecylbenzenesulfonic acid (DBSA).A special technological process of producing the fibres was developed, which prevents from side reactions that occur in polyaniline at higher temperatures. The fibres produced have good morphological and electrical properties. The paper discusses examination results obtained by UV–Vis and Fourier transform infrared (FTIR)

R. Fryczkowski; W. Binia?; J. Farana; B. Fryczkowska; A. W?ochowicz

2004-01-01

217

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

218

The effect of fibre content on the mechanical properties of hemp and basalt fibre reinforced phenol formaldehyde composites  

Microsoft Academic Search

In this study, mechanical properties such as tensile, flexural and impact strengths of hemp\\/phenol formaldehyde (PF), basalt\\/PF and hemp\\/basalt hybrid PF composites have been investigated as a function of fibre loading. Hemp fibre reinforced PF composites and basalt fibre reinforced composites were fabricated with varying fibre loading i.e. 20, 32, 40, 48, 56 and 63 vol%. The hybrid effect of hemp

Sultan Öztürk

2005-01-01

219

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. PMID:23755181

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

2013-01-01

220

Utilisation de la Fibre a Deux Coeurs Non-Lineaire dans les Lasers EN Fibre et Lignes de Transmission  

Microsoft Academic Search

L'utilisation des proprietes non-lineaires de la fibre optique a deux coeurs identiques constitue l'objet de cette etude numerique. Les effets non-lineaires dans les fibres optiques ainsi que la theorie des modes couples sont abordes pour decrire le comportement de la fibre a deux coeurs non-lineaire. On a d'abord analyse les proprietes de transmission d'une telle fibre autour de la puissance

Rene-Jean Essiambre

1994-01-01

221

Fibre Break Failure Processes in Unidirectional Composites. Part 3: Unidirectional Plies Included in Laminates  

NASA Astrophysics Data System (ADS)

The purpose of these three papers is not to just revisit the modelling of unidirectional composites. It is to provide a robust framework based on physical processes that can be used to optimise the design and long term reliability of internally pressurised filament wound structures. The results given in paper Parts 1 and 2 concerning the behaviour of unidirectional composites, such as carbon fibre reinforced epoxy resin, are, here, extended to the behaviour of cross-plied composites consisting of unidirectional plies orientated at different angles with respect to the loading direction. In these laminates the plies orientated parallel to the loading direction (at 0?) control the ultimate failure of the composite. This paper shows that the development of fibre breaks in analogous to that seen in the studies described in Part 1 and 2. Clustering of fibre breaks, shown by the development of 32-plets, preceedes failure just before specimen loaded monotonically break but develop in a more stable manner when subjected to steady high level loads. The effect of separating the 0? plies into thinner layers impedes the development of fibre breaks clusters and increases ultimate lifetimes.

Thionnet, A.; Chou, H. Y.; Bunsell, A.

2014-05-01

222

Influence of fibre length and concentration on the properties of glass fibre-reinforced polypropylene: 4. Impact properties  

Microsoft Academic Search

The results are presented from the final part of a study on the influence of fibre length and concentration on the properties of glass-reinforced polypropylene. Composite impact strength increased directly with increasing fibre concentration. Charpy impact, tensile impact and high speed impact properties increased with fibre length up to 6 mm. A surprising result was that the Charpy impact strength

J. L. Thomason; M. A. Vlug

1997-01-01

223

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

224

The mechanical properties of fibre-metal laminates based on glass fibre reinforced polypropylene  

Microsoft Academic Search

This paper investigates the quasi-static and impact properties of a novel fibre\\/metal laminate system based on a tough glass-fibre-reinforced polypropylene (GFPP). Initial testing has shown that excellent adhesion can be achieved by surface treating the aluminium and incorporating an interlayer based on a maleic-anhydride modified polypropylene copolymer at the interface between the composite and aluminium plies. Single cantilever beam tests

W. J. Cantwell

2000-01-01

225

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

2001-01-01

226

WEAVE MOS fibre bundle test plan  

NASA Astrophysics Data System (ADS)

WEAVE is the next-generation wide-field optical spectroscopy facility for the William Herschel Telescope (WHT) in La Palma, Canary Islands, Spain. WEAVE mainly aims at spectroscopic follow-up of ground-based (e.g. LOFAR) and space-based (GAIA) surveys. The facility consists of a new 2-degree field-of-view prime focus corrector with a 1000- multiplex fibre positioner, a small number of individually deployable integral field units, and a large single integral field unit. The IFUs (Integral Field Units) and the MOS fibres can be used to feed a dual-beam spectrograph that will provide full coverage of the majority of the visible spectrum in a single exposure at a spectral resolution of ~5000 or modest wavelength coverage in both arms at a resolution ~20000. The instrument is expected to be on-sky by 2017 to provide spectroscopic sampling of the fainter end of the Gaia astrometric catalogue, chemical labeling of stars to V~17, and dedicated follow up of substantial numbers of sources from the medium deep LOFAR surveys. After a brief description of the MOS fibre bundle, we described the proposed test plan and the test bench of the 2x1000 WEAVE MOS fibres. The test bench allows us to evaluate the Focal Ratio Degradation and the throughput of the fibers fitted with their buttons and slitlets.

Sayède, Frédéric; Guinouard, Isabelle; Fasola, Gilles; Lhome, Emilie; Amans, Jean-Philippe; Bonifacio, Piercarlo; Abrams, Don Carlos; Middleton, Kevin; Dalton, Gavin; Aguerri, J. Alfonso L.; Trager, Scott C.; Loeb, Avi

2014-07-01

227

Fibre-Coupled Remote Optical Vibrometry.  

National Technical Information Service (NTIS)

This report covers the work performed at the Southampton Optoelectronics Research Center into fibre optic remote vibrometry in the period 1991-1994. A number of instruments have been constructed including a passive homodyne scheme based on 3X3 coupler wit...

A. Lawrow, M. Johnson, H. O. Edwards, C. N. Pannell

1994-01-01

228

Cellulosic fibre-reinforced green composites  

Microsoft Academic Search

Increased environmental awareness and societal needs serve as a catalyst for developing new eco-friendly materials like green composites. In the recent past, researchers have reported the results of their studies on green composites of different plant fibres and various biodegradable matrices. This article is an overview of the various aspects of green composites. Composites based on important biodegradable matrices like

Maya Jacob John; Rajesh D. Anandjiwala; Laly A. Pothan; Sabu Thomas

2007-01-01

229

Dietary fibre, glycaemic response, and diabetes.  

PubMed

The much publicised global trend in rising levels of obesity and diabetes has refuelled interest in the dietary intake of the macronutrients (fat, protein, and carbohydrates) necessary to maintain the state of normalcy (good health) of an individual. Both scientific and public attention have focused on the dietary mediation of chronic health syndromes, either through use of dietary supplements, or a review of the whole diet situation. Dietary supplements have been used extensively both as pharmacological supplements, food ingredients, in processed foods to aid weight control, and the regulation of glucose control for diabetic patients. Particular interest has focused on the use of dietary fibres, especially soluble dietary fibres (such as guar gum, locust bean gum, and psyllium fibres), resistant starch, and slowly digestible carbohydrates. These have been shown to alter food structure, texture, and viscosity, and hence the rate of starch degradation during digestion. Research has also illustrated an association between the rate of carbohydrate degradation during digestion, and the regulation of postprandial blood sugar and insulin levels. The current paper explores the potential use of dietary fibres in the treatment of obesity and diabetes. PMID:15926145

Brennan, Charles S

2005-06-01

230

A fibre laser acoustic vector sensor  

NASA Astrophysics Data System (ADS)

An acoustic vector sensor based on distributed feedback fibre laser technology is reported. The sensor is designed as an accelerometer that will sense acceleration induced by the difference in acoustic pressure across the sensor. Experimental measurements demonstrate that the sensor has excellent response characteristics and sufficient cross-axis discrimination to be a useful acoustic vector sensor.

Jackson, Philip; Foster, Scott; Goodman, Steven

2009-10-01

231

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

232

3D reconstruction of a gas diffusion layer and a microporous layer  

Microsoft Academic Search

The focus of the current study is on a state-of-the-art twin-layer gas diffusion layer (GDL) which consists of carbon tissues with a fibre diameter of 5–20?m, and contains a microporous layer (MPL) coating which has sub-micron porous features. In the current study, real-world digital three-dimensional images of the GDL-MPL assembly are created through X-ray nano-tomography with a 680nm pixel resolution

H. Ostadi; P. Rama; Y. Liu; R. Chen; X. X. Zhang; K. Jiang

2010-01-01

233

Enzyme activities in single electrophysiologically identified crab muscle fibres.  

PubMed

The superficial muscle fibres in the proximal part of the closer muscle in the crab Eriphia can be separated into four fibre groups (I-IV) on the basis of electrophysiological and histochemical characteristics. The activity levels of glyceraldehydephosphate dehydrogenase (GAPDH), lactate dehydrogenase (LDH), citrate synthase (CS), NADP-isocitrate dehydrogenase (IDH) and 3-hydroxyacyl-CoA dehydrogenase (HAD), determined in single electrophysiologically identified fibres, differed significantly among the different fibre groups. In addition, fibres belonging to the same group, with similar electrophysiological characteristics, demonstrated variability with regard to metabolic enzyme activities. Nevertheless, comparison of absolute enzyme activities and enzyme activity ratios permitted the discrimination of at least three groups. These groups corresponded with those defined according to electrophysiological and histochemical characteristics. The group I fibres (tonic fibres) are intermediate in oxidative potential and show the lowest values of glycolytic enzymes. The group II and group III fibres can be regarded as fast oxidative fibres. The high ratio between activity levels of enzymes for glycolytic and oxidative metabolism found for group IV fibres (fast fibres) demonstrated that this group depends strongly on anaerobic metabolism. PMID:3701650

Maier, L; Pette, D; Rathmayer, W

1986-02-01

234

Enzyme activities in single electrophysiologically identified crab muscle fibres.  

PubMed Central

The superficial muscle fibres in the proximal part of the closer muscle in the crab Eriphia can be separated into four fibre groups (I-IV) on the basis of electrophysiological and histochemical characteristics. The activity levels of glyceraldehydephosphate dehydrogenase (GAPDH), lactate dehydrogenase (LDH), citrate synthase (CS), NADP-isocitrate dehydrogenase (IDH) and 3-hydroxyacyl-CoA dehydrogenase (HAD), determined in single electrophysiologically identified fibres, differed significantly among the different fibre groups. In addition, fibres belonging to the same group, with similar electrophysiological characteristics, demonstrated variability with regard to metabolic enzyme activities. Nevertheless, comparison of absolute enzyme activities and enzyme activity ratios permitted the discrimination of at least three groups. These groups corresponded with those defined according to electrophysiological and histochemical characteristics. The group I fibres (tonic fibres) are intermediate in oxidative potential and show the lowest values of glycolytic enzymes. The group II and group III fibres can be regarded as fast oxidative fibres. The high ratio between activity levels of enzymes for glycolytic and oxidative metabolism found for group IV fibres (fast fibres) demonstrated that this group depends strongly on anaerobic metabolism. PMID:3701650

Maier, L; Pette, D; Rathmayer, W

1986-01-01

235

Early deactivation of slower muscle fibres at high movement frequencies.  

PubMed

Animals produce rapid movements using fast cyclical muscle contractions. These types of movements are better suited to faster muscle fibres within muscles of mixed fibre types as they can shorten at faster velocities and achieve higher activation-deactivation rates than their slower counterparts. Preferential recruitment of faster muscle fibres has previously been shown during high velocity contractions. Additionally, muscle deactivation takes longer than activation and therefore may pose a limitation to fast cyclical contractions. It has been speculated that slower fibres may be deactivated before faster fibres to accommodate their longer deactivation time. This study aimed to test whether shifts in muscle fibre recruitment occur with derecruitment of slow fibres before faster fibres at high cycle frequencies. Electromyographic (EMG) signals were collected from the medial gastrocnemius at an extreme range of cycle frequencies and workloads. Wavelets were used to resolve the EMG signals into time and frequency space and the primary sources of variability within the EMG frequency spectra were identified through principal component analysis. Early derecruitment of slower fibres was evident at the end of muscle excitation at higher cycle frequencies, as determined by reduced low-frequency EMG content, and additional slower fibre recruitment was present at the highest cycle frequency. The duration of muscle excitation reached a minimum of about 150 ms and did not change for the three highest cycle frequencies, suggesting a duration limit for the medial gastrocnemius. This study provides further evidence of modifications of muscle fibre recruitment strategies to meet the mechanical demands of movement. PMID:25104756

Blake, Ollie M; Wakeling, James M

2014-10-01

236

Developing new active optical fibres with broadband emissions  

NASA Astrophysics Data System (ADS)

Broadband emission sources such as super luminous diodes and rare earth doped fibre for ASE sources have wide applications in optical fibre measurement and sensing systems. Recent intensive research has shown broadband luminescence in the range of 1100 to 1500 nm, across O, E and S bands of the telecommunications window from glasses or materials with Bi-doping and Bi/Er codoping. The broadband luminescence of active optical fibres in this wavelength range is particularly interesting for fibre amplifiers, lasers and ASE sources for optical communication and sensing applications. Here we report our recent development of Bi/Er/Al codoped phosphogermanosilicate optical fibre with ultra-broadband luminescence between 1000 to 1570 nm, covering O-, E-, S-, C-, and L-bands, when pumped by 532, 808, or 980 nm lasers. The new material composition of this optical fibres are potentially useful as gain media for ultrabroadband ASE sources, tunable fibre lasers or amplifiers.

Peng, Gang-Ding; Zhang, Jianzhong; Luo, Yanhua; Sathi, Zinat; Zareanborji, Amirhassan; Canning, John

2013-09-01

237

A peptide hormone gene, GhPSK promotes fibre elongation and contributes to longer and finer cotton fibre.  

PubMed

Cotton fibres, the single-celled trichomes derived from the ovule epidermis, provide the most important natural material for the global textile industry. A number of studies have demonstrated that regulating endogenous hormone levels through transgenic approaches can improve cotton fibre qualities. Phytosulfokine-? (PSK-?) is a novel peptide hormone in plants that is involved in regulating cell proliferation and elongation. However, its potential applications in crop genetic improvement have not been evaluated. In this study, we describe how exogenous PSK-? application promotes cotton fibre cell elongation in vitro. Chlorate, an effective inhibitor of peptide sulfation, suppressed fibre elongation in ovule culture. Exogenously applied PSK-? partly restored the chlorate-induced suppression. A putative PSK gene (GhPSK) was cloned from Gossypium hirsutum. Expression pattern analysis revealed that GhPSK is preferentially expressed in rapidly elongating fibre cells (5-20 days postanthesis). Overexpression of GhPSK in cotton increased the endogenous PSK-? level and promoted cotton fibre cell elongation, resulting in longer and finer fibres. Further results from electrophysiological and physiological analyses suggest that GhPSK affects fibre development through regulation of K(+) efflux. Digital gene expression (DGE) profile analysis of GhPSK overexpression lines indicates that PSK signalling may regulate the respiratory electron-transport chain and reactive oxygen species to affect cotton fibre development. These results imply that peptide hormones are involved in cotton fibre growth and suggest a new strategy for the biotechnological improvement of cotton fibre quality. PMID:24666593

Han, Jie; Tan, Jiafu; Tu, Lili; Zhang, Xianlong

2014-09-01

238

Optical fibre spectrometer combined with a magnetic resonance sensor for multiple depth monitoring  

NASA Astrophysics Data System (ADS)

Under some circumstances, it is necessary to do optical spectroscopy on a front surface while at the same time monitoring the presence of a hidden metallic layer. Here, a novel sensor system to do this based on the combination of a visible light optical fibre spectrometer with a magnetic resonance eddy current sensor is demonstrated. It is shown that the the eddy current sensor can probe a hidden metallic film placed up to 1 cm behind the dielectric front surface. The combination of two such detection principles allows one to probe layered materials at multiple depths, revealing their electromagnetic properties at different frequencies.

Helseth, L. E.

2013-08-01

239

Modified sensing element of a fibre-optic current sensor based on a low-eigenellipticity spun fibre  

NASA Astrophysics Data System (ADS)

We have proposed and investigated a modified sensing element of a spun fibre current sensor for the case when the beat length of the built-in linear birefringence of the fibre is equal to or less than the spin pitch of its helical structure. The proposed configuration makes it possible to restore the interferometer contrast reduced because of the decrease in the ellipticity of the wavelength-averaged polarisation state of radiation propagating in such spun fibre. The modified sensing element contains two polarisation state converters: one, located at the spun fibre input, produces polarisation with ellipticity equal to the eigenellipticity of the fibre, and the other ensures conversion of the elliptical polarisation to an orthogonal one through mirror reflection at the fibre output. We have also demonstrated that the magneto-optical sensitivity decreases slightly for the analysed spectrum-averaged parameters of the polarisation state of radiation in the spun fibre. Experimental data lend support to the theoretical predictions.

Przhiyalkovsky, Ya V.; Morshnev, S. K.; Starostin, N. I.; Gubin, V. P.

2014-10-01

240

Localized Retinal Nerve Fiber Layer Defects Detected by Optical Coherence Tomography: The Beijing Eye Study  

PubMed Central

Objective To assess the prevalence of localized retinal nerve fiber layer defects (LRNFLD) and associated factors in adult Chinese. Methods The population-based Beijing Eye Study 2011 included 3468 individuals (mean age: 64.6±9.8 years (range: 50–93 years)). The study participants underwent a detailed ophthalmological examination including spectral-domain optical coherence tomography (SpectralisR-OCT) assisted measurement of the RNFL. A LRNFLD was defined as a sector in which the RNFL contour line dipped into the red zone for a length of <180°. Results Readable OCT images were available for 3242 (93.5%) subjects. LRNFLDs were detected in 640 eyes (9.9±0.4%) of 479 subjects (14.8±0.6%). In the age groups of 50–59 years, 60–69 years, 70–79 years, and 80+ years, the prevalence of LRNFLD per person increased from 9.9±0.9%, 11.6±1.0% and 20.6±1.4% to 33.0±3.2%, respectively. In multivariate analysis, prevalence of LRNFLDs was significantly associated with older age (P?=?0.001; Odds Ratio (OR): 1.03; 95% Confidence Interval (CI): 1.01,1.05), myopic refractive error (P<0.001;OR:0.79;95%CI:0.74,0.85), larger beta zone of parapapillary atrophy (P<0.001; OR:1.34;95%CI:1.20,1.50), presence of glaucomatous optic neuropathy (P<0.001;OR:7.02;95%CI:3.87,12.7), presence of non-glaucomatous optic nerve damage (P?=?0.001;OR:43.3;95%CI:8.24,227.1), and presence of diabetic retinopathy (P?=?0.003;OR:2.79;95%CI:1.43,5.44). Conclusions OCT-defined LRNFLDs were present in a prevalence of 14.8±0.6% in a population-based study sample of subjects aged 50+ years. Prevalence of LRNFLDs increased with higher age, myopic refractive error, and larger parapapillary beta zone. Major ocular diseases associated with LRNFLs were glaucoma, non-glaucomatous optic nerve damage and diabetic retinopathy. These data may be helpful for a semiautomatic assessment of the RNFL. PMID:23894392

Zhao, Liang; Wang, Ya Xing; Zhang, Wei; Zhang, Jing Shang; Chen, Chang Xi; Xu, Liang; Jonas, Jost B.

2013-01-01

241

Combustion fronts in porous media with two layers Steve Schecter  

E-print Network

pulses in parallel coupled nerve fibres, SIAM J. Appl. Math., vol. 55 (1995), pp. 1650­1674. Thanks to layer: · porous rock · coke (fuel) · gas = oxygen + other We ignore heat loss to surrounding rock. Reaction: [coke] + [oxygen] [other gas] + [heat] #12;Balance of energy in each layer: t [rock energy

Schecter, Stephen

242

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

243

Large fibre size in skeletal muscle is metabolically advantageous.  

PubMed

Skeletal muscle fibre size is highly variable, and while diffusion appears to limit maximal fibre size, there is no paradigm for the control of minimal size. The optimal fibre size hypothesis posits that the reduced surface area to volume in larger fibres reduces the metabolic cost of maintaining the membrane potential, and so fibres attain an optimal size that minimizes metabolic cost while avoiding diffusion limitation. Here we examine changes during hypertrophic fibre growth in metabolic cost and activity of the Na?-K?-ATPase in white skeletal muscle from crustaceans and fishes. We provide evidence for a major tenet of the optimal fibre size hypothesis by demonstrating that larger fibres are metabolically cheaper to maintain, and the cost of maintaining the membrane potential is proportional to fibre surface area to volume. The influence of surface area to volume on metabolic cost is apparent during growth in 16 species spanning a 20-fold range in fibre size, suggesting that this principle may apply widely. PMID:23851638

Jimenez, Ana Gabriela; Dillaman, Richard M; Kinsey, Stephen T

2013-01-01

244

A novel cryogenic fibre maker for continuous extrusion  

NASA Astrophysics Data System (ADS)

The results of a cryogenics fibre maker which extrudes fibres continuously are presented. The fibre maker is based on a simple concept of differential temperature. Two reservoirs are connected in cascade and are kept at different temperatures. The first reservoir is connected to an external gas line supply (the gas that will made the fibre) and is used to liquefy the gas. The second reservoir is colder that the first and the liquid that comes from the first reservoir is frozen and later is used to form the fibre. The pressure of external gas supply in the first reservoir is used to extrude the fibre. The system is cooled by a two stage closed cycle refrigerator, which uses liquid helium as a working fluid. The nozzles used to extrude the fibre are made of stainless steel capillary with diameters between 50 ?m and 250 ?m, with a length of 2 mm. The use of a system with two independent temperatures, permits to control the extrusion rate of the fibres and to produce the fibres continuously. Using this system, hydrogen deuterium, nitrogen and argon fibres of various diameters were extruded.

Aliaga-Rossel, R.; Bayley, J.

1997-05-01

245

In vitro bacterial fermentation of tropical fruit fibres.  

PubMed

Tropical fruits such as mango, papaya, pineapple and banana are rich sources of dietary fibre. However, few studies have examined the potential physiological effects of fibre from these tropical fruits. The aim of this study was to characterise the fermentability of dietary fibre found in banana, papaya, pineapple and mango as an estimate of the physiological effects of consuming these fruits. Freeze-dried fruit was subjected to in vitro digestion to remove digestible carbohydrates. Digestion residues were freeze-dried prior to fermentation. In vitro fermentation was carried for 24 h under anaerobic conditions to simulate conditions in the large intestine. Gas volume, pH and short chain fatty acids (SCFAs) concentration were measured at 0, 4, 8, 12, and 24 h. SCFAs were analysed by gas chromatography. There was no gas production from 0 to 8 h time points for all samples. Mango fibre resulted in more gas at 12 and 24 h than pineapple, papaya and banana fibres. The slurry pH was significantly lower for mango fibre at 12 and 24 h compared to other samples. Mango fibre resulted in significantly more propionate at 8 h compared to papaya and pineapple fibres. Butyrate concentrations were only significantly different at 4 h. At 24 h total and individual SCFA production did not differ among samples. All fruit fibres were fermentable, with mango fibre being the most rapidly fermented. Additional work is necessary to confirm a benefit on digestive health. PMID:23887033

Vong, M H; Stewart, M L

2013-09-01

246

Fibre laser component technology for 2-micron laser systems  

NASA Astrophysics Data System (ADS)

We report on recent developments in fibre laser component technology for use in 2-micron laser systems. A range of `building block' components has been built to allow novel fibre laser architectures that exploit the advantages of fibre lasers based on Thulium and Holmium active fibres. Fibre lasers operating around 2-microns are becoming widely used in an increasing number of applications, which is driving the need for components that can operate reliably at high powers and also integrate easily with other components. To that end, we have designed and built a range of fused fibre, acousto-optic and magneto-optic devices that can be readily integrated into a range of novel fibre laser systems. Research has been carried out into improving fused fibre technology for components operating at 2um wavelengths. Side-coupled feed through combiners have been developed with signal losses as low as 0.02dB and kilowatt level end-coupled pump couplers. Alongside this a range of taps, splitters and WDMs have been developed which allows for the implementation of a variety of laser architectures. Optical isolators based on new Faraday materials have been developed, providing over 30dB isolation, low insertion loss and 30W power handling in a fibre-in, fibre-out version. New cell designs and materials for Acousto-Optic devices have been researched leading to the development of fibre-coupled Acousto-Optic Modulators (AOM) and allows for the realisation of all fibre Thulium and Holmium Q-switched and pulsed fibre lasers. Novel Acousto-Optic Tunable Filters (AOTF) designs have been realised to produce narrow resolution AOTFs and zero-shift AOTFs.

Stevens, G.; Robertson, A.

2014-05-01

247

Fibre Bragg grating acoustic emissions and transmission sensor in carbon fibre composites  

NASA Astrophysics Data System (ADS)

Acoustic sensors are used in Structural Health Monitoring (SHM) for the detection of impacts and strain. However, secondary damage may result from the initial damage. This secondary damage, such as delamination or cracking, may not be detectable by the SHM system. This is a significant problem for passive sensing systems, such as those based on fibre optics, where signals cannot be actively generated to interrogate the structure. The integration of NDE by robotic agents into a SHM sensor network enables the detection and monitoring of a wider variety of damage. Communicating via acoustic transmissions represents a wireless communication method for robotic agents to communicate to the SHM system without the addition of extra hardware, as piezoelectric transducers are commonly used in NDE. The effect of Carbon Fibre Composites (CFC) on the ability to use acoustic transmission needs to be determined. We present results for the detection of Acoustic Emissions and Transmissions (AET) in a CFC laminate. The optical fibre AET detector was a Fibre Bragg Grating (FBG). Two FBG AET sensors were compared, one coupled to the surface of the carbon fibre sheet, and one embedded within the lay-up. Results compare the transfer function, frequency response, and transient response of the sensors. The embedded FBG receiver was also used to detect an actively generated acoustic transmission. A piezoelectric receiver was also used for comparison. The embedded FBG was found to give significantly better performance in all of the parameters considered for the surface coupled FBG.

Wild, Graham; Hinckley, Steven

2008-12-01

248

Polymerizing the fibre between bacteria and host cells: the biogenesis of functional amyloid fibres  

PubMed Central

Summary Amyloid fibres are proteinaceous aggregates associated with several human diseases, including Alzheimer’s, Huntington’s and Creutzfeldt Jakob’s. Disease-associated amyloid formation is the result of proteins that misfold and aggregate into ? sheet-rich fibre polymers. Cellular toxicity is readily associated with amyloidogenesis, although the molecular mechanism of toxicity remains unknown. Recently, a new class of ‘functional’ amyloid fibres was discovered that demonstrates that amyloids can be utilized as a productive part of cellular biology. These functional amyloids will provide unique insights into how amyloid formation can be controlled and made less cytotoxic. Bacteria produce some of the best-characterized functional amyloids, including a surface amyloid fibre called curli. Assembled by enteric bacteria, curli fibres mediate attachment to surfaces and host tissues. Some bacterial amyloids, like harpins and microcinE492, have exploited amyloid toxicity in a directed and functional manner. Here, we review and discuss the functional amyloids assembled by bacteria. Special emphasis will be paid to the biology of functional amyloid synthesis and the connections between bacterial physiology and pathology. PMID:18373633

Epstein, Elisabeth Ashman; Chapman, Matthew R.

2009-01-01

249

Macroscopic assembled, ultrastrong and H2SO4-resistant fibres of polymer-grafted graphene oxide  

PubMed Central

Nacre realizes strength and toughness through hierarchical designs with primary “brick and mortar” structures of alternative arrangement of nanoplatelets and biomacromolecules, and these have inspired the fabrication of nanocomposites for decades. However, to simultaneously solve the three critical problems of phase separation, low interfacial strength and random orientation of nanofillers for nanocomposites is a great challenge yet. Here we demonstrate that polymer-grafted graphene oxide sheets are exceptional building blocks for nanocomposites. Their liquid crystalline dispersions can be wet-spun into continuous fibres. Because of well-ordering and efficient load transfer, the composites show remarkable tensile strength (500?MPa), three to four times higher than nacre. The uniform layered microstructures and strong interlayer interactions also endow the fibres good resistance to chemicals including 98% sulfuric acid. We studied the enhancing effect of nanofillers with fraction in a whole range (0–100%), and proposed an equation to depict the relationship. PMID:24196491

Zhao, Xiaoli; Xu, Zhen; Zheng, Bingna; Gao, Chao

2013-01-01

250

Macroscopic assembled, ultrastrong and H(2)SO(4)-resistant fibres of polymer-grafted graphene oxide.  

PubMed

Nacre realizes strength and toughness through hierarchical designs with primary "brick and mortar" structures of alternative arrangement of nanoplatelets and biomacromolecules, and these have inspired the fabrication of nanocomposites for decades. However, to simultaneously solve the three critical problems of phase separation, low interfacial strength and random orientation of nanofillers for nanocomposites is a great challenge yet. Here we demonstrate that polymer-grafted graphene oxide sheets are exceptional building blocks for nanocomposites. Their liquid crystalline dispersions can be wet-spun into continuous fibres. Because of well-ordering and efficient load transfer, the composites show remarkable tensile strength (500?MPa), three to four times higher than nacre. The uniform layered microstructures and strong interlayer interactions also endow the fibres good resistance to chemicals including 98% sulfuric acid. We studied the enhancing effect of nanofillers with fraction in a whole range (0-100%), and proposed an equation to depict the relationship. PMID:24196491

Zhao, Xiaoli; Xu, Zhen; Zheng, Bingna; Gao, Chao

2013-01-01

251

Multiphoton absorption in amyloid protein fibres  

NASA Astrophysics Data System (ADS)

Fibrillization of peptides leads to the formation of amyloid fibres, which, when in large aggregates, are responsible for diseases such as Alzheimer's and Parkinson's. Here, we show that amyloids have strong nonlinear optical absorption, which is not present in native non-fibrillized protein. Z-scan and pump-probe experiments indicate that insulin and lysozyme ?-amyloids, as well as ?-synuclein fibres, exhibit either two-photon, three-photon or higher multiphoton absorption processes, depending on the wavelength of light. We propose that the enhanced multiphoton absorption is due to a cooperative mechanism involving through-space dipolar coupling between excited states of aromatic amino acids densely packed in the fibrous structures. This finding will provide the opportunity to develop nonlinear optical techniques to detect and study amyloid structures and also suggests that new protein-based materials with sizable multiphoton absorption could be designed for specific applications in nanotechnology, photonics and optoelectronics.

Hanczyc, Piotr; Samoc, Marek; Norden, Bengt

2013-12-01

252

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. PMID:23881131

Chong, Su Sin; Abdul Aziz, A. R.; Harun, Sulaiman W.

2013-01-01

253

RD1 scintillating fibre calorimeter studies  

NASA Astrophysics Data System (ADS)

A report is given of the experimental studies on lead/fibre calorimetry of the RD1 research and development project. To match the LHC physics requirements for a highly segmented and accurate electromagnetic energy measurement and for an acceptable hadronic performance, the 1992 RD1 program opted for longitudinally segmented calorimeter prototypes. The electromagnetic prototypes comprised 4 × 4 cm 2 cells with a high sampling fraction of 1.8:1. Coarse hadronic prototypes were constructed using 1 mm fibres inserted in 3 mm diameter plastic tubes. The production procedures are discussed and test beam results are presented. Reports are also given on calibration studies, on radiation hardness studies and on the development and tests of new light detectors.

Linssen, L.; RD1 Collaboration

1994-04-01

254

Microscopic Study on Hemp Bast Fibre Formation  

Microsoft Academic Search

Commonly, fibre hemp (Cannabis sativa) is not considered for the production of soft and easy-care textiles. However, initial tests in the textile industry have shown that certain processes allow improvement in the everyday-wear characteristics of hemp textiles. In the framework of the EU R&D project Hemp-sys [QLRT-01-01363] the potential of hemp as a feedstock in textile processing is investigated. Therefore,

Arancha Hernandez; Wim Westerhuis; Jan E. G. van Dam

2007-01-01

255

14—RIGIDITY, MOISTURE AND FIBRE STRUCTURE  

Microsoft Academic Search

Results are given showing the relation between the modulus of torsional rigidity and moisture regain for ramie, mercerized cotton, Fortisan, viscose rayon, wool and nylon. For all the cellulose fibres, the equation loge(G\\/G65) = — 0·;82[(M\\/M65)—1] describes the observed relation between rigidity (G) and moisture regain (M) in terms of the values of these quantities at 65% r.h.The results are

R. Meredith

1957-01-01

256

42—NEW REACTIONS IN REDUCED WOOL FIBRES  

Microsoft Academic Search

The ·SH-groups in reduced wool react quickly and smoothly with vinyl sulphones as occurs with cysteine in model experiments. From this, an analytical method is developed for determining the extent of reduction in wool. Bifunctional divinyl sulphone leads to an extensive network formation in the fibres. Dimethyl maleate and N-p-phenetyl maleinimide also react quickly with ·SH-wool. These alkylating agenls replace

A. Schöberl

1960-01-01

257

Elastic fibres and vascular structure in hypertension.  

PubMed

Blood vessels are dynamic structures composed of cells and extracellular matrix (ECM), which are in continuous cross-talk with each other. Thus, cellular changes in phenotype or in proliferation/death rate affect ECM synthesis. In turn, ECM elements not only provide the structural framework for vascular cells, but they also modulate cellular function through specific receptors. These ECM-cell interactions, together with neurotransmitters, hormones and the mechanical forces imposed by the heart, modulate the structural organization of the vascular wall. It is not surprising that pathological states related to alterations in the nervous, humoral or haemodynamic environment-such as hypertension-are associated with vascular wall remodeling, which, in the end, is deleterious for cardiovascular function. However, the question remains whether these structural alterations are simply a consequence of the disease or if there are early cellular or ECM alterations-determined either genetically or by environmental factors-that can predispose to vascular remodeling independent of hypertension. Elastic fibres might be key elements in the pathophysiology of hypertensive vascular remodeling. In addition to the well known effects of hypertension on elastic fibre fatigue and accelerated degradation, leading to loss of arterial wall resilience, recent investigations have highlighted new roles for individual components of elastic fibres and their degradation products. These elements can act as signal transducers and regulate cellular proliferation, migration, phenotype, and ECM degradation. In this paper, we review current knowledge regarding components of elastic fibres and discuss their possible pathomechanistic associations with vascular structural abnormalities and with hypertension development or progression. PMID:16488477

Arribas, Silvia M; Hinek, Aleksander; González, M Carmen

2006-09-01

258

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

2012-04-01

259

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

260

Effects of chemical treatments on hemp fibre structure  

NASA Astrophysics Data System (ADS)

In this study, hemp fibres were treated with alkali, acetyl and silane chemicals. Fibre constituents such as cellulose, hemicellulose and lignin constituents were separated from treated fibres. The chemical and thermal influences of these constituents on the treated fibres were examined by using scanning electron microscope (SEM), fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Experimental results revealed that, hemicellulose was degraded faster than that of cellulose and lignin. Cellulose exhibited better thermal stability and lignin was degraded in a wide range of temperatures. The hydrophilic nature of the fibres was predominantly caused by the presence of hemicellulose and then lignin constituents. Hemicellulose and lignin were mostly removed by the alkalisation with higher concentrations of NaOH, followed by acetylation. Silane treatment could not remove the hemicellulose and lignin, rather this treatment facilitated coupling with the fibre constituents.

Kabir, M. M.; Wang, H.; Lau, K. T.; Cardona, F.

2013-07-01

261

The spectral dispersion curves of highly oriented fibres  

Microsoft Academic Search

Spectral dispersion curves of the refractive indices and birefringence of highly oriented fibres [poly(ethylene 2,6-naphthalene-dicarboxylate) (1000 denier\\/248 filaments, PEN-Q50M4; PEN), poly(ethylene terephthalate) (PET), Seun yarn (meta-aramid fibres, Teijin Japan; CONEX) and Technora T-240 (1000 denier\\/667 filaments aramid fibres, Teijin Japan; TECHNORA)] have investigated using the automatic variable-wavelength interferometric (VAWI) technique. This technique is especially recommended for measuring the refractive indices

A. A Hamza; I. M Fouda; T. Z. N Sokkar; M. A El-Bakary

2001-01-01

262

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

263

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

264

Lead silicate microstructured optical fibres for electro-optical applications.  

PubMed

We report progress towards the realization of optical modulators based on electro-optic effects in soft glass fibres. A hybrid fabrication procedure was developed for producing microstructured lead silicate glass fibres with internal electrodes. Electro-optical characterization confirms experimentally that the enhanced nonlinear properties and superior isolation between the optical field and the electrodes make these fibres an ideal candidate platform for efficient electro-optical devices. PMID:24514705

Zhang, Wen Qi; Manning, Sean; Ebendorff-Heidepriem, Heike; Monro, Tanya M

2013-12-16

265

Coir fibre toxicity: in vivo and in vitro studies.  

PubMed

The biological activity of coir fibre, coir ash and their components were investigated in vitro by measuring the haemolytic activity and macrophage cytotoxicity. In vivo studies carried out by injecting guinea pigs intratracheally with coir fibres resulted in resolving granulomas. The observed haemolytic activity and macrophage cytotoxicity was more marked with coir ash compared with coir fibres. Chemical analysis of coir ash revealed the presence of toxic chemical constituents in appreciable amounts. PMID:6283694

Saxena, R P; Dogra, R K; Bhattacherjee, J W

1982-03-01

266

Ultrafiltration Equipment Using Hollow Fibres and Areas of Application  

Microsoft Academic Search

A technological process for production of hollow polysulfone fibres of asymmetric structure with retentivity of 20 kD and distilled water ultrafiltration rate of 94-125 liter\\/(m2·h) with transmembrane pressure of 0.1 MPa and temperature of 25±1°C was developed. Four types of fibre ultrafiltration devices which can be rapidly installed and dismantled in water treatment plant were developed. Production of fibre ultrafiltration

V. A. Bakunov; L. F. Maiboroda

2001-01-01

267

Strength of silica optical fibre subjected to chemical environment  

NASA Astrophysics Data System (ADS)

Based on the increased interest for optical fibres development for the use in smart structures and sensors, this study has aimed to investigate the chemical reliability of standard commercial epoxy-acrylate polymer coated fibres subjected to aggressive chemical reagents in gaseous and liquid phase, such as acetylene, ammoniac, dimethyl sulfoxide. Multimode optical fibre was exposed to gaseous reagents for different durations after prior vide exposure. Tensile testing results were treated using Weibull statistics. A comparison of mean failure strength of as-aged fibres to the water influence for similar exposure duration has revealed the highest sensitivity to dimethyl sulfoxide reagent.

Severin, Irina; El Abdi, Rochdi; Poulain, Marcel; Caramihai, Mihai

2010-11-01

268

High power resonantly pumped holmium-doped fibre sources  

NASA Astrophysics Data System (ADS)

Holmium-doped fibres provide a power scalable gain-medium capable of operation at wavelengths beyond 2.05 ?m. We discuss and review our approach to the power scaling of pulsed and CW laser sources at 2.1 ?m using holmium-doped fibres. This paper outlines experiments which demonstrate the wavelength region accessible using holmium-doped silica fibres, as well as a linearly polarised pulsed master-oscillator power amplifier and high average power CW laser and amplifier systems. These devices demonstrate the applicability of holmium fibre lasers to a range of scientific, medical, industrial and defence applications.

Hemming, Alexander; Simakov, Nikita; Haub, John; Carter, Adrian

2014-03-01

269

Performance of Hemp-Fibre Reinforced Polypropylene Composite Materials.  

E-print Network

??Increasing worldwide environmental awareness is encouraging scientific research into the development of cheaper, more environmentally friendly and more sustainable construction and packaging materials. Natural fibre… (more)

Beckermann, Gareth

2007-01-01

270

Passively Q-switched Ytterbium and Chromium all-fibre laser  

E-print Network

A chromium-doped saturable absorber fibre stabilizes an otherwise spontaneously chaotic ytterbium- doped fibre laser. This original passively Q-switched all-fibre laser produces sustained and stable trains of smooth pulses at high repetition rate.

Dussardier, Bernard; Peterka, Pavel

2012-01-01

271

Specimen specific parameter identification of ovine lumbar intervertebral discs: On the influence of fibre-matrix and fibre-fibre shear interactions.  

PubMed

Numerical models of the intervertebral disc, which address mechanical questions commonly make use of the difference in water content between annulus and nucleus, and thus fluid and solid parts are separated. Despite this simplification, models remain complex due to the anisotropy and nonlinearity of the annulus and regional variations of the collagen fibre density. Additionally, it has been shown that cross-links make a large contribution to the stiffness of the annulus. Because of this complex composite structure, it is difficult to reproduce several sets of experimental data with one single set of material parameters. This study addresses the question to which extent the ultrastructure of the intervertebral disc should be modelled so that its moment-angle behaviour can be adequately described. Therefore, a hyperelastic constitutive law, based on continuum mechanical principles was derived, which does not only consider the anisotropy from the collagen fibres, but also interactions among the fibres and between the fibres and the ground substance. Eight ovine lumbar intervertebral discs were tested on a custom made spinal loading simulator in flexion/extension, lateral bending and axial rotation. Specimen-specific geometrical models were generated using CT images and T2 maps to distinguish between annulus fibrosus and nucleus pulposus. For the identification of the material parameters the annulus fibrosus was described with two scenarios: with and without fibre-matrix and fibre-fibre interactions. Both scenarios showed a similar behaviour on a load displacement level. Comparing model predictions to the experimental data, the mean RMS of all specimens and all load cases was 0.54±0.15° without the interaction and 0.54±0.19° when the fibre-matrix and fibre-fibre interactions were included. However, due to the increased stiffness when cross-links effects were included, this scenario showed more physiological stress-strain relations in uniaxial and biaxial stress states. Thus, the present study suggests that fibre-matrix and fibre-fibre interactions should be considered in the constitutive law when the model addresses questions concerning the stress field of the annulus fibrosus. PMID:24361932

Reutlinger, Christoph; Bürki, Alexander; Brandejsky, Vaclav; Ebert, Lars; Büchler, Philippe

2014-02-01

272

Fibre optical sensor for C 2H 2 gas using gas-filled photonic bandgap fibre reference cell  

Microsoft Academic Search

We present results from the first optical fibre correlation spectroscopy gas sensor which uses no lenses other than in the measurement gas cell. The sensor measures acetylene (C2H2) gas concentration. A 1-m length of photonic bandgap fibre (PBGF) was filled with acetylene at atmospheric pressure, then fusion spliced to standard, solid-core, single-mode SMF-28 fibre to form a compact, coilable, reference

Ed Austin; Adriaan van Brakel; Marco N. Petrovich; David J. Richardson

2009-01-01

273

Mossy fibre and climbing fibre responses produced in the cerebellar cortex by stimulation of the cerebral cortex in monkeys  

Microsoft Academic Search

Summary  \\u000a1. \\u000aResponses in the cerebellar cortex induced by stimulation of several areas of the cerebral cortex were recorded and identified electro-physiologically to be due to mossy fibre and climbing fibre volleys, and their distributions were explored in the anterior and the posterior lobes of the cerebellum in monkeys. Early mossy and late climbing fibre responses at latencies of 4–5

K. Sasaki; H. Oka; S. Kawaguchi; K. Jinnai; T. Yasuda

1977-01-01

274

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

275

A comparison of the effects of fibre alignment of smooth and textured fibres in electrospun membranes on fibroblast cell adhesion  

Microsoft Academic Search

A polyester polycaprolactone-based polyurethane elastomer (PU) and poly-(l-lactide) (PLLA), two common biomaterials, were electrospun to produce membranes with fibres either randomly orientated or aligned. PU was used to produce membranes consisting of smooth fibres. PLLA was used to prepare fibres with a textured surface. Contact angle measurements of the PU and PLLA cast films reveal that they were both below

Yen B. Truong; Veronica Glattauer; Gregor Lang; Karen Hands; Ilias L. Kyratzis; Jerome A. Werkmeister; John A. M. Ramshaw

2010-01-01

276

THE ELASTICITY OF SPECIAL-SHAPED FIBRE SIMULATION BY HYDROMECHANICAL SIMULATION SOFTWARE  

Microsoft Academic Search

Physical or chemical processes produce properties in man-made fibres similar to those of natural fibres. In nature, fibres have irregularly-shaped cross sections, whereas man-made fibres have circle-shaped cross sections. In order to mimic the properties of natural fibres and their characteristics, this research work focused on a fibre with a star-shaped cross-section, which was expected to be the best for

Hsiao-Chi Tsai; Chin-An Lin; Chi-Che Tung

277

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. PMID:19822550

Campero, M; Baumann, T K; Bostock, H; Ochoa, J L

2009-01-01

278

Design of single-mode large-mode area bandgap fibre with microstructured-core  

NASA Astrophysics Data System (ADS)

Tailoring the modal characteristics of all-solid photonic bandgap fibre by the inclusion of low-index rods in the fibre core is investigated. By lowering the core index of the fibre, the high-order modes in the fibre can be shifted to the border of the bandgap, as a result, single-mode operation in large-mode area bandgap fibre can be realized without bending the fibre. In addition, large-mode area and single-mode operation in the all-solid microstructured-core bandgap fibre can be achieved by bending the fibre at a wide bending radius range.

Chen, Ming-Yang; Gong, Tian-Yi; Gao, Yong-Feng; Zhou, Jun

2014-11-01

279

Ultrasound detection of damage in complex carbon fibre/metal structures  

NASA Astrophysics Data System (ADS)

We describe work carried out to monitor the structural health of a complex structure comprising both carbon fibre and metal components using ultrasound techniques. The work is designed to be used in a high performance car, but could find applications in other areas such as the aerospace industry. There are two different types of potential problem that need to be examined; the first is damage (e.g. holes, delaminations) to carbon fibre structure, and the second is damage to joints either between two carbon fibre components or between a carbon fibre component and a metallic one. The techniques used are based around the use of PZT transducers for both the generation and detection of ultrasonic Lamb waves. To date we have been carrying out experiments on mock-up samples, but are due to conduct tests on an actual vehicle. Lamb waves propagate in modes whose order is determined by the frequency thickness product. Their properties, such as phase and amplitude can be modified by the presence of damage, such as holes and delaminations. If we record the response of a healthy structure, we can then compare it with signals obtained on subsequent occasions to determine if any significant change has taken place. It is essential, however, to be able to differentiate between the effects of damage and those of environmental changes such as temperature. For this reason we have monitored the response of a sample at different temperatures both before and after drilling a hole in it to simulate damage. Depending on the positions of the transducers with respect to the damaged area, it is possible to detect either attenuation of the entire signal or changes in a specific portion of the signal produced by reflections. Results from these experiments will be presented at the conference. Signal processing techniques for separating damage from the effects of temperature will also be discussed. We also look at the deterioration of joints, which can either be epoxy bonded (carbon fibre to carbon fibre) or bolted together (carbon fibre to aluminium). In the case of the bonded structures we are looking at the effects of failure of the bond layer, whilst in the case of the bolted samples we are looking at loosening of the bolts. The debonding was simulated by joining together a flat plate of carbon fibre composite with an L-shaped carbon fibre piece using a couplant such as grease. Similar experiments were carried out using an aluminium anglebar bolted to the plate, with the bolts both tightened and loose. Signals of both the transmitted wave in the plate and the power coupled to the L piece were measured before and after debonding. This gives a more reliable measure of the change in power transfer between the two components as the joint/bond degrades. It was found that in order to get maximum coupling to the second component the frequency of the acoustic wave had to be altered. This is because in the bonding region the combined thickness of the components alters the modal propagation characteristics of the structure compared with those of the single component region.

Thursby, G. J.; MacLean, A.; Hogg, H.; Culshaw, B.

2006-03-01

280

Holmium fibre laser with record quantum efficiency  

SciTech Connect

We report holmium-doped fibre lasers with a Ho{sup 3+} concentration of 1.6 x 10{sup 19} cm{sup -3} and lasing wavelengths of 2.02, 2.05, 2.07 and 2.1 {mu}m at a pump wavelength of 1.15 {mu}m. The slope efficiency of the lasers has been measured. The maximum efficiency, 0.455, has been obtained at a lasing wavelength of 2.05 {mu}m. The laser efficiency is influenced by both the optical loss in the wing of a vibrational absorption band of silica and active-ion clustering. (lasers)

Kurkov, Andrei S; Sholokhov, E M; Tsvetkov, V B; Marakulin, A V; Minashina, L A; Medvedkov, O I; Kosolapov, A F

2011-06-30

281

The design and performance of a scintillating-fibre tracker for the cosmic-ray muon tomography of legacy nuclear waste containers  

NASA Astrophysics Data System (ADS)

Tomographic imaging techniques using the Coulomb scattering of cosmic-ray muons are increasingly being exploited for the non-destructive assay of shielded containers in a wide range of applications. One such application is the characterisation of legacy nuclear waste materials stored within industrial containers. The design, assembly and performance of a prototype muon tomography system developed for this purpose are detailed in this work. This muon tracker comprises four detection modules, each containing orthogonal layers of Saint-Gobain BCF-10 2 mm-pitch plastic scintillating fibres. Identification of the two struck fibres per module allows the reconstruction of a space point, and subsequently, the incoming and Coulomb-scattered muon trajectories. These allow the container content, with respect to the atomic number Z of the scattering material, to be determined through reconstruction of the scattering location and magnitude. On each detection layer, the light emitted by the fibre is detected by a single Hamamatsu H8500 MAPMT with two fibres coupled to each pixel via dedicated pairing schemes developed to ensure the identification of the struck fibre. The PMT signals are read out to standard charge-to-digital converters and interpreted via custom data acquisition and analysis software.

Clarkson, A.; Hamilton, D. J.; Hoek, M.; Ireland, D. G.; Johnstone, J. R.; Kaiser, R.; Keri, T.; Lumsden, S.; Mahon, D. F.; McKinnon, B.; Murray, M.; Nutbeam-Tuffs, S.; Shearer, C.; Staines, C.; Yang, G.; Zimmerman, C.

2014-05-01

282

Polarization-based data storage in fibre ring lasers  

Microsoft Academic Search

The possibility of storing information in an amplifying optical fibre loop operating in a laser regime is discussed. Numerical simulations show that storage is possible and optimal when data are encoded in one of the polarization eigenstates of the fibre, provided the polarization direction of the light propagating inside the loop is switched between two orthogonal states every round trip.

J. García-Ojalvo; R. Roy

1998-01-01

283

Development of tailor-made silica fibres for TL dosimetry  

NASA Astrophysics Data System (ADS)

The Ge dopant in commercially available silica optical fibres gives rise to appreciable thermoluminscence (TL), weight-for-weight offering sensitivity to MV X-rays several times that of the LiF dosimeter TLD100. The response of these fibres to UV radiation, X-rays, electrons, protons, neutrons and alpha particles, with doses from a fraction of 1 Gy up to 10 kGy, have stimulated further investigation of the magnitude of the TL signal for intrinsic and doped SiO2 fibres. We represent a consortium effort between Malaysian partners and the University of Surrey, aimed at production of silica fibres with specific TL dosimetry applications, utilizing modified chemical vapour deposition (MCVD) doped silica-glass production and fibre-pulling facilities. The work is informed by defect and dopant concentration and various production dependences including pulling parameters such as temperature, speed and tension; the fibres also provide for spatial resolutions down to <10 ?m, confronting many limitations faced in use of conventional (TL) dosimetry. Early results are shown for high spatial resolution (~0.1 mm) single-core Ge-doped TL sensors, suited to radiotherapy applications. Preliminary results are also shown for undoped flat optical fibres of mm dimensions and Ge-B doped flat optical fibres of sub-mm dimensions, with potential for measurement of doses in medical diagnostic applications.

Bradley, D. A.; Abdul Sani, Siti F.; Alalawi, Amani I.; Jafari, S. M.; Noor, Noramaliza M.; Hairul Azhar, A. R.; Mahdiraji, Ghafour Amouzad; Tamchek, Nizam; Ghosh, S.; Paul, M. C.; Alzimami, Khalid S.; Nisbet, A.; Maah, M. J.

2014-11-01

284

An All Optical Fibre Quantum Controlled-NOT Gate  

E-print Network

We report the first experimental demonstration of an optical controlled-NOT gate constructed entirely in fibre. We operate the gate using two heralded optical fibre single photon sources and find an average logical fidelity of 90% and an average process fidelity of 0.83gate itself works with very high fidelity.

Clark, Alex S; Rarity, John G; Wadsworth, William J; O'Brien, Jeremy L

2008-01-01

285

An All Optical Fibre Quantum Controlled-NOT Gate  

E-print Network

We report the first experimental demonstration of an optical controlled-NOT gate constructed entirely in fibre. We operate the gate using two heralded optical fibre single photon sources and find an average logical fidelity of 90% and an average process fidelity of 0.83gate itself works with very high fidelity.

Alex S. Clark; Jeremie Fulconis; John G. Rarity; William J. Wadsworth; Jeremy L. O'Brien

2008-02-12

286

Muscle fibre types of fishes; structural and functional specialization  

Microsoft Academic Search

Muscles of fishes are active in a variety of movements that differ in velocity, duration and excursion length. To investigate how muscles meet the, often conflicting, demands imposed upon them by these movements, the fibre type composition of several muscles was determined. The ultrastructural and contractile properties of some of the obtained fibre types were measured and compared with their

H. A. Akster

1984-01-01

287

Natural fibres as reinforcement in polylactic acid (PLA) composites  

Microsoft Academic Search

The focus in this work has been to study if natural fibres can be used as reinforcement in polymers based on renewable raw materials. The materials have been flax fibres and polylactic acid (PLA). PLA is a thermoplastic polymer made from lactic acid and has mainly been used for biodegradable products, such as plastic bags and planting cups, but in

K. Oksman; M. Skrifvars; J.-F. Selin

2003-01-01

288

Semiconductor disk laser-pumped subpicosecond holmium fibre laser  

SciTech Connect

The first passively mode-locked holmium fibre laser has been demonstrated, with a semiconductor saturable absorber mirror (SESAM) as a mode locker. Semiconductor disk lasers have been used for the first time to pump holmium fibre lasers. We obtained 830-fs pulses at a repetition rate of 34 MHz with an average output power of 6.6 mW.

Chamorovskiy, A Yu; Marakulin, A V; Leinonen, T; Kurkov, Andrei S; Okhotnikov, Oleg G

2012-01-31

289

Diametral compression tests of silicon carbide fibre-reinforced glass  

Microsoft Academic Search

Diametral compression tests were carried out for unidirectionally aligned silicon carbide fibrereinforced borosilicate glass. The fracture load dependence on the angle between the loading axis and the fibre alignment was investigated. The stress components in the fibre-aligned plane were calculated to evaluate the effect of the shear stress on fracture. Weibull statistics were employed to estimate the fracture load dependence

Akira Okada

1990-01-01

290

Material property estimates from ultrasound attenuation in fibre suspensions.  

PubMed

An investigation of a new method for measuring fibre material properties from ultrasonic attenuation in a dilute suspension of synthetic fibres of uniform geometry is presented. The method is based on inversely solving an ultrasound scattering and absorption model of suspended fibres in water for the material properties of the fibres. Experimental results were obtained from three suspensions of nylon 66 fibres each with different fibre diameters. A forward solution to the model with reference material values is compared to experimental data to verify the model's behaviour. Estimates of the shear and Young's modulus, the compressional wave velocity, Poisson's ratio and loss tangent from nylon 66 fibres are compared to data available from other sources. Experimental data confirms that the model successfully predicts that the resonance features in the frequency response of the attenuation are a function of diameter. Consistent estimated values for the compressional wave velocity and the Poisson's ratio were found to be difficult to obtain but in combination gave values of shear modulus within previously reported values and with low sensitivity to noise. Young's modulus was underestimated by 54% but was consistent and had low sensitivity to noise. The underestimation is believed to be caused by the assumption of isotropic material used in the model. Additional tests on isotropic fibre would confirm this. Further analysis of the model sensitivity and the reasons for the resonance features are required. PMID:19157476

Aitomäki, Yvonne; Löfqvist, Torbjörn

2009-05-01

291

STRATEGY FOR A SUSTAINABLE FUTURE OF FIBRE CROPS  

Microsoft Academic Search

During the last decade, there have been great efforts in the EEC to establish flax and hemp as a sustainable source for fibres. Although almost every German car manufacturer uses now natural fibre reinforced parts, most of the raw material for the low level application comes still from Eastern Europe and Asia at cheap prices. Thus, the strategy to establish

R. W. Kessler; R. Kohler; M. Tubach

292

Fibre operating lengths of human lower limb muscles during walking  

PubMed Central

Muscles actuate movement by generating forces. The forces generated by muscles are highly dependent on their fibre lengths, yet it is difficult to measure the lengths over which muscle fibres operate during movement. We combined experimental measurements of joint angles and muscle activation patterns during walking with a musculoskeletal model that captures the relationships between muscle fibre lengths, joint angles and muscle activations for muscles of the lower limb. We used this musculoskeletal model to produce a simulation of muscle–tendon dynamics during walking and calculated fibre operating lengths (i.e. the length of muscle fibres relative to their optimal fibre length) for 17 lower limb muscles. Our results indicate that when musculotendon compliance is low, the muscle fibre operating length is determined predominantly by the joint angles and muscle moment arms. If musculotendon compliance is high, muscle fibre operating length is more dependent on activation level and force–length–velocity effects. We found that muscles operate on multiple limbs of the force–length curve (i.e. ascending, plateau and descending limbs) during the gait cycle, but are active within a smaller portion of their total operating range. PMID:21502124

Arnold, Edith M.; Delp, Scott L.

2011-01-01

293

Composite micromechanics of hemp fibres and epoxy resin microdroplets  

Microsoft Academic Search

It is shown that the microdeformation of single hemp fibres can be monitored by following the peak shift of the 1095 cm?1 Raman band with respect to strain and stress. This relationship is then used to monitor the deformation micromechanics of strained single hemp fibres with a microdroplet of epoxy resin attached along the gauge length. It is shown that

S. J. Eichhorn; R. J. Young

2004-01-01

294

ADHESION IMPROVEMENT OF CARBON FIBRES BY PLASMA SURFACE MODIFICATION  

E-print Network

matrices for enhancing longitudinal tensile strength of carbon fibre reinforced polymer (CFRP) composites, He/O2 and Ar plasma treatments. CFRP composite plates were prepared using both untreated and He reinforced polymers (CFRP) (Dilsiz 2000). However, due to the non-polar nature of carbon fibres

295

The effects of commercial fibres on frozen bread dough  

Microsoft Academic Search

The daily intake of dietary fibres in highly industrialized countries is at a low level and, therefore, adversely affecting human health. The objective of this research was to analyze the influence of different commercial fibres (ori- ginating from sugar beet pulp fibrex, and Jerusalem artichoke inulin HPX and GR) in yeast dough at a level of 5 %, on the

NADA FILIPOVI?; Cara Lazar; Bul Cara Lazar

2010-01-01

296

Developments in and applications of fibre optic intrusion detection sensors  

Microsoft Academic Search

For many years optical fibre was the answer looking for the question. Now, after years of product applications and continued development, a range of fibre optic sensors are used in intrusion detection where the natural benefits of the material are matched by parallel developments in support technologies and applications experience. This paper describes some developments and applications in sensors and

B. Griffiths

1995-01-01

297

41—SETTING PROPERTIES OF KERATIN FIBRES IN RELATION TO STRUCTURE  

Microsoft Academic Search

Earlier work on the setting of skunk guard-hairs in borax has been extended to fibres from six other mammals. Considerable variations have been found in the extent and stability of the set achieved. When set at zero extension, fibres from the skunk, Russian hare, kolinsky, and mink do not contract in boiling 5% metabisulphite solution. Reindeer, whitecoat and Chungking pig

J. L. Stoves

1960-01-01

298

Surface characterisation of low temperature plasma-treated wool fibre  

Microsoft Academic Search

Previous investigation results revealed that after the low temperature plasma (LTP) treatment, the hydrophilicity of wool fibres was improved significantly. Such improvement enhances the wool dyeing and finishing processes which might be due to the changes of the wool surface to a more reactive one. In this paper, wool fibres were treated with LTP with different gases, namely oxygen, nitrogen

C. W. Kan; C. W. M. Yuen

2006-01-01

299

A new cap for kinetochore fibre minus ends.  

PubMed

In mitotic spindles, each sister chromatid is directly attached to a spindle pole through microtubule bundles known as kinetochore fibres. Microspherule protein 1 (MCRS1) is now shown to support spindle assembly by localizing to the minus ends of kinetochore fibres and protecting them from depolymerization. PMID:22081093

Petry, Sabine; Vale, Ronald D

2011-12-01

300

A new cap for kinetochore fibre minus ends  

PubMed Central

In mitotic spindles, each sister chromatid is directly attached to a spindle pole through microtubule bundles known as kinetochore fibres. Microspherule protein 1 (MCRS1) is now shown to support spindle assembly by localizing to the minus ends of kinetochore fibres and protecting them from depolymerization. PMID:22081093

Petry, Sabine

2012-01-01

301

A Scintillating Fibre Tracker for the LHCb Upgrade  

NASA Astrophysics Data System (ADS)

A scintillating fibre tracker with multichannel silicon photomultiplier readout is an option for the LHCb upgrade. The radiation hardness of the scintillating fibres and silicon photomultipliers has been studied. Production methods and machines to build 5m long modules with an accuracy of 50 ?m have been designed and built. All developments are well on track for the technical design report in March 2014.

Ekelhof, Robert

2014-06-01

302

Solid particle erosion of unidirectional fibre reinforced thermoplastic composites  

Microsoft Academic Search

In the present study, the solid particle erosion behaviour of neat PEEK matrix and unidirectional glass fibre (GF) and carbon fibre (CF) reinforced polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) composites has been studied. The erosion experiments have been carried out by using silica sand particles (200±50?m) as an erodent. Steady state erosion rates of these composites have been evaluated at different

Arjula Suresh; A. P. Harsha; M. K. Ghosh

2009-01-01

303

Characterisation of fibre metal laminates under thermomechanical loadings  

Microsoft Academic Search

Fibre metal laminates, such as Arall or Glare, can offer improved properties compared to monolithic materials. Glare for example shows improved fatigue, residual strength, burn-through, impact and corrosion properties with respect to aluminium 2024, together with a considerable weight reduction and competitive costs. A large research program has proven the technological readiness of Glare and the fibre metal laminate has

M. Hagenbeek

2005-01-01

304

Flexible ceramic-reinforced polyurethane composite coatings on synthetic fibres: Process of continuous liquid film coating and its influence on the coating thickness  

Microsoft Academic Search

A concept for the realisation of composite layers on the surface of synthetic fibres by continuous liquid film coating of spread roving or monofilaments with a slurry containing ceramic particles and a polymeric binder is successfully demonstrated. Polyamide 6 monofilaments were coated with alumina particles and a polyurethane elastomer based binder system to achieve higher abrasion resistance. Under frictional load,

Felix A. Reifler; Felipe A. L. Sánchez; Frank J. Clemens; Ksenija Varga; Rudolf Hufenus

2010-01-01

305

Advanced materials and techniques for fibre-optic sensing  

NASA Astrophysics Data System (ADS)

Fibre-optic monitoring systems came of age in about 1999 upon the emergence of the world's first significant commercialising company - a spin-out from the UK's collaborative MAST project. By using embedded fibre-optic technology, the MAST project successfully measured transient strain within high-performance composite yacht masts. Since then, applications have extended from smart composites into civil engineering, energy, military, aerospace, medicine and other sectors. Fibre-optic sensors come in various forms, and may be subject to embedment, retrofitting, and remote interrogation. The unique challenges presented by each implementation require careful scrutiny before widespread adoption can take place. Accordingly, various aspects of design and reliability are discussed spanning a range of representative technologies that include resonant microsilicon structures, MEMS, Bragg gratings, advanced forms of spectroscopy, and modern trends in nanotechnology. Keywords: Fibre-optic sensors, fibre Bragg gratings, MEMS, MOEMS, nanotechnology, plasmon.

Henderson, Philip J.

2014-06-01

306

Chrysotile and tremolite asbestos fibres in the lungs and parietal pleura of Corsican goats  

PubMed Central

Methods: Ten goats from areas with asbestos outcrops and two from other areas were slaughtered. Fibre content of lung and parietal pleural samples was determined by analytical transmission electron microscopy. Results: Both chrysotile and tremolite fibres were detected. In the exposed goats, the geometric mean concentrations of asbestos fibres longer than 1 µm were 0.27 x 106 fibres/g dry lung tissue and 1.8 x 106 fibres/g dry pleural tissue. Asbestos fibres were not detected in the lungs of the two control goats. Chrysotile fibres shorter than 5 µm were predominant in the parietal pleura. Tremolite fibres accounted for 78% and 86% of the fibres longer than 5 µm in lung and parietal pleural samples, respectively. Conclusions: Environmental exposure in northeast Corsica results in detectable chrysotile and tremolite fibre loads in the lung and parietal pleura of adult goats. Tremolite fibres of dimensions with a high carcinogenic potency are detected in the parietal pleura. PMID:12205241

Dumortier, P; Rey, F; Viallat, J; Broucke, I; Boutin, C; De Vuyst, P

2002-01-01

307

Alignement automatise de fibres optiques amorces monomodes  

NASA Astrophysics Data System (ADS)

Cette these jette les bases necessaires au developpement d'algorithmes a base de modele pour l'automatisation de l'alignement de fibres amorces monomodes. A partir de la methode de l'integrale de recouvrement et de deux solutions approximatives existantes, un modele analytique d'efficacite de couplage optique permettant d'estimer la puissance transmise entre un composant et une fibre amorce monomode est d'abord formule. Avec celui-ci, sept proprietes pouvant etre utiles au developpement d'algorithmes a base de modele sont ensuite identifiees et validees. Enfin, a l'aide de ces proprietes, une strategie d'alignement a base de modele est developpee et validee experimentalement. Les resultats obtenus demontrent clairement la repetitivite, la robustesse, la precision et la rapidite de la strategie proposee. Ils demontrent aussi qu'il est possible de realiser un alignement complet sans l'utilisation de systemes auxiliaires tels des systemes de vision, des cameras infrarouges, des capteurs de contact ou des systemes de fixation hautement precis.

St-Amant, Yves

308

Effects of dietary fibre on behaviour and satiety in pigs.  

PubMed

During the past decades there has been considerable interest in the use of dietary fibre in both animal and human nutrition. In human subjects dietary fibre has been studied intensively for possible effects on body-weight management and health. In animal nutrition the interest in dietary fibre has increased because it can be used as a cheap source of energy and because of its potential to improve animal welfare and reduce abnormal (mainly stereotypic) behaviour. Animal welfare is impaired if the diet does not provide sufficient satiety, combined with an environment that does not meet specific behavioural requirements related to natural feeding habits (e.g. rooting in pigs). A considerable proportion of the behavioural effects of dietary fibre are thought to be related to reduced feeding motivation. It has been hypothesized that: (1) bulky fibres increase satiety and thereby decrease physical activity and stereotypic behaviours immediately following a meal in pigs; (2) fermentable fibres prolong postprandial satiety and thereby reduce physical activity and appetitive behaviours for many hours after a meal. The validity of these hypotheses is examined by considering published data. In sows dietary fibres (irrespective of source) reduce stereotypic self-directed behaviours and substrate-directed behaviours, and to a lesser extent overall physical activity, indicating enhanced satiety shortly after a meal. Furthermore, fermentable dietary fibre reduces substrate-directed behaviour in sows and physical activity in sows and growing pigs for many hours after a meal. Evidence of long-term effects of poorly-fermentable fibre sources is inconclusive. The findings suggest that highly-fermentable dietary fibres have a higher potential to prolong postprandial satiety. PMID:18715518

de Leeuw, J A; Bolhuis, J E; Bosch, G; Gerrits, W J J

2008-11-01

309

Comparative evaluation of steel mesh, steel fibre and high-performance polypropylene fibre reinforced shotcrete in panel test  

Microsoft Academic Search

In this study, experimental investigations were performed on steel mesh (SM), steel fibre (SF) and high-performance polypropylene fibre (HPPF) reinforced shotcrete (HPPFRS) panels to evaluate performance characteristics such as toughness, flexural ductility, energy absorption and load capacity. The panel tests, in accordance with European specification for sprayed concrete (EFNARC), were made on 18 prismatic specimens having the same mix designs

O Cengiz; L Turanli

2004-01-01

310

BIOMIMETIC INTEREST AND POSSIBILITIES FOR REPLACEMENT OF GLASS FIBRES WITH PLANT FIBRES IN COMPOSITE MATERIALS: THE CASE OF IMPACT DAMAGE  

Microsoft Academic Search

In this paper, the sense and importance of a biomimetic approach to materials is discussed, highlighting the most characteristic aspects of this philosophy. In particular, attention is brought then on the possibility for improvement of plant fibres for composite materials reinforcement with the aim of looking at them as a substitute for E-glass fibres, presenting benefits in terms of environmental

C. SANTULLI

311

The Effect of Breed Type, Fibre Length, and Fibre Diameter on the Efficiency of Dehairing Cashmere in Sample Test Dehairers  

Microsoft Academic Search

A modified Shirley Analyser has been shown previously to be effective in removing guard hair from down-bearing goat fleeces. The technique used was shown to be capable of dehairing fleeces of both cashmere and Angora x cashmere types. The latter fleece type is characterized by the increased length and fibre diameter of down fibres. This paper reports an investigation of

R. C. Couchman

1989-01-01

312

High altitude tissue adaptation in Andean coots: capillarity, fibre area, fibre type and enzymatic activities of skeletal muscle  

Microsoft Academic Search

Capillarity, fibre types, fibre area and enzyme activities of different skeletal muscles (pectoralis, extensor digitorum longus), tibialis anterior, plantaris and the myocardium were compared in Andean coot (Fulica americana peruviana) native to high altitude (Junín, Perú, 4200 m) and the same species nesting at sea level. Numbers of capillaries per square millimeter were higher in all high-altitude muscles when compared

F. León-Velarde; J. Sanchez; A. X. Bigard; A. Brunet; C. Lesty; C. Monge-C

1993-01-01

313

Determining the fibrillar orientation of bast fibres with polarized light microscopy: the modified Herzog test (red plate test) explained.  

PubMed

The identification of bast fibre samples, in particular, bast fibres used in textiles, is an important issue in archaeology, criminology and other scientific fields. One of the characteristic features of bast fibres is their fibrillar orientation, referred to as Z- or S twist (or alternatively right- and left-handed fibres). An empirical test for determining the fibrillar orientation using polarized light microscopy has been known in the community for many years. It is referred to as the modified Herzog test or red plate test. The test has the reputation for never producing false results, but also for occasionally not working. However, so far, no proper justification has been provided in the literature that the 'no false results' assumption is really correct and it has also not been clear up till now, why the method sometimes does not work. In this paper, we present an analytical model for the modified Herzog test, which explains why the test never gives a false result. We also provide an explanation for why the Herzog test sometimes does not work: According to our model, the Herzog test will not work if none of the three distinct layers in the secondary cell wall is significantly thicker than the others. PMID:24020614

Haugan, E; Holst, B

2013-11-01

314

High altitude tissue adaptation in Andean coots: capillarity, fibre area, fibre type and enzymatic activities of skeletal muscle.  

PubMed

Capillarity, fibre types, fibre area and enzyme activities of different skeletal muscles (pectoralis, extensor digitorum longus), tibialis anterior, plantaris and the myocardium) were compared in Andean coot (Fulica americana peruviana) native to high altitude (Junín, Perú, 4200 m) and the same species nesting at sea level. Numbers of capillaries per square millimeter were higher in all high-altitude muscles when compared with sea-level muscles (P < 0.0001). Moreover, values for capillaries per fibre and capillaries in contact with each fibre were higher in digitorum and tibialis high-altitude muscles. Muscle fibres were classified as Type I, Type IIA or Type IIB on the basis of their myofibrillar ATPase pH lability. Pectoralis muscle of high-altitude and sea-level coots presented only fibres of Type IIA. In contrast, all the leg muscles studied showed a mosaic pattern of the three fibre types. Fibre areas were determined using a Leitz Texture Analysis System. Significant differences in fibre area were observed (P < 0.01) between high-altitude and sea-level muscles. Mean muscle fibre diameters were also lower in the high-altitude group than in the sea-level group. The enzyme activities studied were hexokinase, lactate dehydrogenase, citrate synthase and 3-hydroxyacyl-CoA-dehydrogenase. The oxidative capacity, as reflected by citrate synthetase and hydroxyacyl-CoA-dehydrogenase activities, was greater for myocardial and pectoralis than for leg muscles. However, analysis of maximal enzyme activities showed that there were no significant differences between the glycolytic and oxidative enzyme activities of high-altitude and sea-level coots.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8459054

León-Velarde, F; Sanchez, J; Bigard, A X; Brunet, A; Lesty, C; Monge, C

1993-01-01

315

Structured spheres generated by an in-fibre fluid instability.  

PubMed

From drug delivery to chemical and biological catalysis and cosmetics, the need for efficient fabrication pathways for particles over a wide range of sizes, from a variety of materials, and in many different structures has been well established. Here we harness the inherent scalability of fibre production and an in-fibre Plateau-Rayleigh capillary instability for the fabrication of uniformly sized, structured spherical particles spanning an exceptionally wide range of sizes: from 2?mm down to 20?nm. Thermal processing of a multimaterial fibre controllably induces the instability, resulting in a well-ordered, oriented emulsion in three dimensions. The fibre core and cladding correspond to the dispersed and continuous phases, respectively, and are both frozen in situ on cooling, after which the particles are released when needed. By arranging a variety of structures and materials in a macroscopic scaled-up model of the fibre, we produce composite, structured, spherical particles, such as core-shell particles, two-compartment 'Janus' particles, and multi-sectioned 'beach ball' particles. Moreover, producing fibres with a high density of cores allows for an unprecedented level of parallelization. In principle, 10(8) 50-nm cores may be embedded in metres-long, 1-mm-diameter fibre, which can be induced to break up simultaneously throughout its length, into uniformly sized, structured spheres. PMID:22810590

Kaufman, Joshua J; Tao, Guangming; Shabahang, Soroush; Banaei, Esmaeil-Hooman; Deng, Daosheng S; Liang, Xiangdong; Johnson, Steven G; Fink, Yoel; Abouraddy, Ayman F

2012-07-26

316

HIGH PERFORMANCE NATURAL FIBRE REINFORCED SHEET MOLDING COMPOUND FOR AUTOMOTIVE APPLICATIONS  

Microsoft Academic Search

This research work aims to replace glass fibres in sheet molding compounds (SMC) by renewable natural fibres. These eco-efficient and cost effective SMC with natural fibres are gaining much attention in the automotive industry because of their specific properties. The specific objective of the work was to develop a high performance natural fibre hybrid SMC to meet the specifications required

Merry Lo; Suhara Panthapulakkal; Mohini Sain

317

The Diameters of the Fibres of the Peripheral Nerves of Octopus  

Microsoft Academic Search

The diameters and numbers of fibres have been measured throughout the peripheral nervous system. The nerves of the muscles that act upon the outside world contain few fibres, having very large and medium-sized fibres but no very small ones. Thus the muscles of the head receive 6000 fibres, the largest of 30 mu m diameter. The eye muscles receive 3300

J. Z. Young

1965-01-01

318

Mechanical properties of self-compacting concrete reinforced with polypropylene fibres  

E-print Network

Mechanical properties of self-compacting concrete reinforced with polypropylene fibres O. Gencel*1, the workability and mechanical properties of SCC with fly ash reinforced with monofilament polypropylene fibres no problems with mixing or workability when the fibre distribution is uniform. The polypropylene fibres

North Texas, University of

319

Fibre interactions in two-dimensional composites by micro-Raman spectroscopy  

Microsoft Academic Search

In the study of fracture processes in composite materials, the interactions between broken and intact fibres are of critical importance. Indeed, the redistribution of stress from a failed fibre to its unfailed adjacent neighbours, and the stress concentration induced in these, determine the extent to which a break in one fibre will cause more breaks in neighbouring fibres. The overall

H. D. Wagner; M. S. Amer; L. S. Schadler

1996-01-01

320

A procedure for identifying textile bast fibres using microscopy: Flax, nettle\\/ramie, hemp and jute  

Microsoft Academic Search

Identifying and distinguishing between natural textile fibres is an important task in both archaeology and criminology. Wool, silk and cotton fibres can readily be distinguished from the textile bast fibres flax, nettle\\/ramie, hemp and jute. Distinguishing between the bast fibres is, however, not easily done and methods based on surface characteristics, chemical composition and cross section size and shape are

Christian Bergfjord; Bodil Holst

2010-01-01

321

Adhesion and Wettability Characteristics of Chemically Modified Banana Fibre for Composite Manufacturing  

Microsoft Academic Search

In this work banana fibre was chemically modified using various chemical agents. The surface energy of the fibre is an important parameter and one which governs the interaction of fibre with polymeric matrices. This paper describes the influence of various chemical treatments on the surface energy of the banana fibre investigated by contact angle measurements, spectroscopic analysis and surface morphology

K. N. Indira; Y. Grohens; C. Baley; S. Thomas; K. Joseph; L. A. Pothen

2011-01-01

322

Capillarity of flax\\/linseed ( Linum usitatissimum L.) and fibre hemp ( Cannabis sativa L.) straw fractions  

Microsoft Academic Search

In a study of the wetting properties of the fractions of unretted and frost-retted fibre straws a method to separate fibre, fine shive, and coarse shive from fibre plants is introduced and tested on bast fibre plants (Linum usitatissimum L. and Cannabis sativa L.) The method consists of optional drying of stalks, cutting of straws, milling the straws with a

H.-R Kymäläinen; M Hautala; R Kuisma; A Pasila

2001-01-01

323

EFFECT OF ACIDIC CONDITIONS ON INTERFACE AND STRENGTH OF CELLULOSE FIBRES  

E-print Network

Composites were made with furan as matrix and aligned hemp fibres as reinforcement to obtain a completely based fibres from hemp and flax it is important that a good interface is established and that the fibresH-level) that the fibres can tolerate without severe degradation. Composites were made with aligned hemp yarn in furan

324

LETTERS TO THE EDITOR: High-power single-mode neodymium fibre laser  

Microsoft Academic Search

A double-clad single-mode neodymium fibre laser was constructed. The cw output power of the laser was 3 W at the wavelength of 1.06 mum. The fibre laser was pumped by a fibre-coupled diode laser array. The efficiency of the fibre laser was 43%.

Evgenii M. Dianov; A. V. Belov; Igor'A. Bufetov; V. N. Protopopov; A. N. Gur'yanov; D. D. Gusovskii; S. V. Kobis

1997-01-01

325

Growth of sub-micron fibres of pure polyaniline using the electrospinning technique  

Microsoft Academic Search

In this work we report on the formation of pure polyaniline fibres by the electrospinning method. The fibres present diameters ranging from hundreds of nanometres to a few micrometres and have lengths of hundreds of micrometres. The fibres were collected on SiO2\\/Si and Si wafer pieces in the form of isolated fibres. Morphological characterization by scanning electron microscopy shows smooth

J. R. Cárdenas; M. G. O. de França; E. A. de Vasconcelos; W. M. de Azevedo; E. F. da Silva Jr.

2007-01-01

326

Mechanical modification of degummed jute fibre for high value textile end uses  

Microsoft Academic Search

The effects of pretreatment and mechanical modification on characteristics of jute fibre were evaluated in this paper. The experimental results show that pretreatments and mechanical modifications both have obvious effects on the characteristics of jute fibre. The blended agent used for pretreatment can form a thin film on the surface of jute fibre to make it smoother, so the fibre

Lifang Liu; Qianli Wang; Zhaopeng Xia; Jianyong Yu; Longdi Cheng

2010-01-01

327

All-fibre photonic crystal distributed Bragg reflector (PC-DBR) fibre laser  

NASA Astrophysics Data System (ADS)

We describe an Er3+-doped aluminosilicate core photonic crystal fibre laser incorporating distributed Bragg reflectors written by two-photon 193nm irradiation through an optical phase mask as the feedback elements. The laser is diode pumped at 980nm and evidence of dual linewidth laser operation close to threshold is observed. However, at higher pumping levels gain competition preferentially selects one laser line.

Canning, J.; Groothoff, N.; Buckley, E.; Ryan, T.; Lyytikainen, K.; Digweed, J.

2003-08-01

328

From fibres to networks using self-assembling peptides.  

PubMed

We have investigated the self-assembly and gelation properties of the octapeptide FEFEFKFK (F: phenylalanine; E: glutamic acid; K lysine) as a function of media pH. Temperature vs. concentration phase diagrams were constructed using the test tube tilting method at each pH. The fibre morphology and network topology formed were investigated using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), transmission electron microscopy (TEM) small angle X-ray scattering (SAXS) and oscillatory rheology. In this work we show that changing the charge modulus carried by the peptide through modification of the media pH leads to a change in the self-assembly and gelation behaviour of the peptide. At low (<6) and high (>8) pHs different fibre morphologies were encountered resulting in the formation of hydrogels with different mechanical properties. This change in fibre morphology from rigid to twisted is thought to be due to a change in the intrinsic twist of the beta-sheet ladder formed by the peptide. At low pH the network topology formed by the fibres was shown to affect the concentration dependency of the storage modulus. In particular, the tendency to form laterally associated thicker fibres was shown to lead to hydrogels with higher moduli. The lateral assembly of the fibre is controlled by the charge modulus carried by the peptide; as the charge modulus decreases, the electrostatic repulsion between fibres decreases. As a result the tendency of the fibres to associate laterally increases due to their intrinsic hydrophobicity, which leads to the formation of stronger gels. In the pH range 6-8 the peptide becomes non-charged and large bundles of aggregated fibres are observed. PMID:24611277

Boothroyd, Stephen; Millerb, Aline F; Saiani, Alberto

2013-01-01

329

Optimization of erbium-ytterbium fibre laser with simple double-clad structure  

NASA Astrophysics Data System (ADS)

The paper deals with optimization of fibre laser based on experimental erbium- and ytterbium-doped fibre with simple double-clad structure pumped by multimode laser diode in 980 nm band. Fibre preparation and its characteristics are described. Different resonator configurations were investigated for the laser optimization, including high reflectivity fibre loop mirror. Experimental optimization ofthe pump wavelength, fibre length and output coupler ratio were carried out. The results obtained under the cladding pumping are compared with those measured with a fibre ring laser containing the same fibre single-mode pumped at 1060 nm.

Peterka, Pavel; Kašík, Ivan; Kube?ek, Václav; Mat?jec, Vlastimil; Hayer, Miloš; Honzátko, Pavel; Zavadilova, Alena; Dvo?á?ek, Pavel

2006-03-01

330

K-theory with fibred control.  

E-print Network

Controlled methods proved to be very effective in the study of assembly maps in algebraic K-theory. For the questions concerning surjectivity of these maps in the context of geometries that have no immanent nonpositive curvature, the setting needs to be enlarged to bounded G-theory with fibred control. We set up the natural framework for this theory. As should be expected, the G-theory has better excision properties. The main result illustrates a fact that has no analogue in bounded K-theory. It is one of the major technical tools used in our work on the Borel Conjecture about topological rigidity of aspherical manifolds. The general framework we develop will be useful for other applications to coarse bundles and stacks.

Gunnar Carlsson; Boris Goldfarb

331

Biaxial extension of knitted steel fibre fabrics  

NASA Astrophysics Data System (ADS)

In this paper knitted steel fibre fabrics will be tested in biaxial extension. An in-house developed biaxial extension machine is used to apply a variety of strain conditions, which allows investigating the coupling between the wale and course direction of the fabrics and the degree of anisotropy in the fabric. Prior to testing a pretension level, to compensate the slack nature of the fabric, is determined by using a laser-measuring device. The strain inside the fabric is measured using a CCD camera technique. The results show the non-linear behaviour of the fabric and the coupling between the wale and the course direction. This will lead to a test protocol that can be used to evaluate the biaxial response of different types of knitted fabrics.

Vanclooster, K.; Eshghyar, A.; Lomov, S. V.

2011-05-01

332

UV ozone modification of wool fibre surfaces  

NASA Astrophysics Data System (ADS)

An ultraviolet (UV) ozone treatment has been used to oxidise the surfaces of batches of natural wool fibres. The changes in surface composition and chemistry induced by this treatment have been followed using X-ray photoelectron spectroscopy (XPS). Oxidation of surface di-sulphide sulphur to sulphonic acid groups (- SO3H) containing S6+ is observed at levels of approximately 90% conversion. This is significantly higher than levels previously achieved using oxygen plasmas. The treatment also appears to cause reaction of the proteinaceous carbon, leading to an increase in carbon-oxygen, particularly carbonyl, functionality. The data presented indicate that the treatment used is capable of producing surface sulphur and carbon chemistry of the type usually obtained by wet chlorination.

Bradley, R. H.; Clackson, I. L.; Sykes, D. E.

1993-10-01

333

Auger spectroscopy study of MgLi melt affected carbon/pyrocarbon fibres  

NASA Astrophysics Data System (ADS)

Mg-12wt.% Li matrix composite reinforced with T300 carbon fibres coated with pyrolytic carbon (˜100 nm) was manufactured by the infiltration of the carbon fibre bundle with MgLi melt. The fibre/matrix chemistry was studied by means of in situ Auger electron spectroscopy of the fibre jacket and the fibre cross-fracture in ultra-high vacuum broken composite bars. The fibre bulk attack with lithium is concluded wherein C(KVV) lineshape indicates that lithium carbide is the only reaction product, and its distribution in the fibre bulk is quite uniform. Magnesium penetrates also the fibre bulk but its role in the fibre attack is marginal. It is assumed that lithium carbide is formed as a dispersed minor phase in the fibre bulk via decomposition of intermediate lithium intercalation products.

Kúdela, S.; John, A.; Baunack, S.; Kúdela, S.; Wetzig, K.

2001-07-01

334

Estimation of axial stiffness of plant fibres from compaction of non-woven mats  

NASA Astrophysics Data System (ADS)

Plant fibres are known to show a large variability in stiffness, which makes it time-consuming to experimentally characterize this property by conventional tensile testing. In this work, an alternative method is used, where the average fibre stiffness is back-calculated from compaction tests of in-plane randomly oriented fibre mats. The model by Toll is used to relate the load-displacement curve from the test to the Young modulus of the fibre, taking into account the natural variability in fibre cross section. Several tests have been performed on hemp fibre mats and compared with results from single-fibre tensile testing. The average back-calculated Young's modulus of the fibres was 45 GPa, whereas the average value from tensile testing ranged from 30 to 60 GPa. The straightforward compaction test can be useful in ranking of fibre stiffness, provided that the mat is composed of well-separated fibres and not of twisted yarns.

Gamstedt, E. K.; Bommier, E.; Madsen, B.

2014-03-01

335

Electrostriction mechanism of Bragg grating formation in germanosilicate fibres  

SciTech Connect

An electrostriction model is proposed for the photorefractive effect observed during the writing of Bragg gratings in germanosilicate fibres. Electrostriction is caused by a spatial charge grating formed upon the exposure to UV radiation. According to our estimate, the contribution of electrostriction to the photorefractive effect under real writing conditions is comparable with the contribution from colour centres and exceeds the contribution from the electrooptical effect by more than an order of magnitude. The electrostriction model explains the production of the IIA type Bragg grating in fibres with a high content of germanium in the core, as well as a number of effects that could not be explained earlier. (optical fibres)

Neustruev, V B [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2001-11-30

336

Actuation behaviour of layered composites of polyaniline, carbon nanotubes and polypyrrole  

Microsoft Academic Search

Layered composites of polyaniline (PAn), single-walled carbon nanotubes (CNTs) and polypyrrole (PPy) were produced by coating PAn or PAn\\/CNT on a PPy hollow fibre containing a platinum (Pt) helix. The actuation behaviour of PAn\\/PPy and PAn\\/CNT\\/PPy composites was compared with that of neat PPy. The Pt helix reduces the IR drop along the fibre, thus enhancing the actuation strain. Components

Geoffrey M. Spinks; Binbin Xi; Van-Tan Truong; Gordon G. Wallace

2005-01-01

337

Deposition of zirconia sols on woven fibre preforms using a dip-coating technique  

Microsoft Academic Search

The technique of depositing zirconia coatings onto woven fibre mats has been investigated in detail. The application of a coating to the fibre is essentially one of the easiest methods of providing a fibre–matrix interface with desired properties. Such coatings can act as reaction barriers or as fibre–matrix debond interfaces. This particular coating method, which is the dip-coating of fibre

X Gu; P. A Trusty; E. G Butler; C. B Ponton

2000-01-01

338

Optical properties of active bismuth centres in silica fibres containing no other dopants  

SciTech Connect

Optical fibre preforms and fibres with a bismuth-doped silica core containing no other dopants have been fabricated by the powder-in-tube technique. The optical loss has been measured for the first time in such fibres in a wide spectral range, from 190 to 1700 nm. We have studied the luminescence of active bismuth centres and the luminescence lifetime for some of their bands in both the preforms and the fibres drawn out from them. (optical fibres)

Bufetov, Igor' A; Semenov, S L; Vel'miskin, V V; Firstov, Sergei V; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Bufetova, G A [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2010-09-10

339

Lung Fibre Burden in Lung Cancer Cases Employed in the Rock and Slag Wool Industry  

Microsoft Academic Search

Objectives: To evaluate the relationship between estimated exposure to man-made vitreous fibres (MMVF) and to asbestos fibres and their concentration in the lung tissue of lung cancer cases amongst MMVF production workers. Methods: Retrospective retrieval of available lung tissue specimens was conducted following a case-control study that assessed estimated occupational exposures of MMVF workers. Fibre recoveryandanalysisbytransmissionelectronmicroscopy(TEM)wereconductedtodetermine fibre type, fibre dimension

K. SOLDAN; F. D. POOLEY; J. HANSEN; A. ANDERSEN; J. CHANG-CLAUDE; G. FERRO; H. OHGAKI; B. GULDHAMMER SKOV; J. W. CHERRIE; R. SARACCI; P. BOFFETTA

2005-01-01

340

Microstructure and mechanical properties of in-situ network composite fibres of PBZT with nylon  

Microsoft Academic Search

A method for preparing composite fibres by infiltrating nylon into swollen poly(p-phenylene benzobisthiazole) (PBZT) fibre is described. PBZT fibre forms a microfibrillar network structure during the coagulation process.In-situ network composite (IC) fibres may be prepared by exchanging the coagulant with a solution containing the desired matrix material. These new composite fibres exhibit nearly identical mechanical properties and similar thermomechanical properties

C. R. Hwang; M. F. Malone; R. J. Farris; D. C. Martin; E. L. Thomas

1991-01-01

341

Photonic bandgap single-mode optical fibre with ytterbium-doped silica glass core  

SciTech Connect

A photonic bandgap fibre with an ytterbium-doped silica glass core is fabricated and investigated. The possibility of implementing single-mode operation of such fibres in a wide spectral range at a large (above 20 {mu}m) mode field diameter makes them promising for fibre lasers and amplifiers. To ensure a high quality of the beam emerging from the fibre, particular attention is paid to increasing the optical homogeneity of the ytterbium-doped core glass. (optical fibres)

Egorova, O N; Semenov, S L; Vel'miskin, V V; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Salganskii, M Yu; Yashkov, M V; Gur'yanov, Aleksei N [Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

2011-01-24

342

Structuring of glass fibre surfaces by laser-induced front side etching  

NASA Astrophysics Data System (ADS)

The fabrication of sub-?m structures on glass fibre surfaces poses a big challenge for the laser processing. However, the laser-induced front side etching (LIFE) method has a great potential for the fast, nm-precision, and cost-effective production of surface structures. LIFE is a method for laser etching of transparent materials using thin absorber layers with a high absorption coefficient like metal layers. The LIFE process of the front surface of a fused silica wafer as well as of a glass fibre is studied in dependence on the laser parameters. A KrF excimer laser with a wavelength of 248 nm and a pulse duration of 25 ns was used. The resultant structures were analysed with microscopic methods (white light interferometry, scanning electron microscopy (SEM)). The analysing of the surface structures presented that the LIFE methods allow the fabrication of well-defined periodic sub-?m structures. Furthermore, the structuring process was simulated by a thermodynamic equation including an approach of the laser-plasma interaction. The theoretically predicted results presented a good agreement with the experimental results.

Lorenz, Pierre; Ehrhardt, Martin; Zimmer, Klaus

2014-05-01

343

NANOCOMPOSITE BASED STRUCTURAL HEALTH MONITORING APPROACHES FOR FIBRE REINFORCED POLYMERS  

E-print Network

NANOCOMPOSITE BASED STRUCTURAL HEALTH MONITORING APPROACHES FOR FIBRE REINFORCED POLYMERS for Polymers and Composites, Denickestr. 15, 21073 Hamburg, Germany 2 Physics Department, Faculty of Science reinforced polymer (FRP) structures in many industrial branches. Different approaches for Structural Health

Boyer, Edmond

344

Graphene chiral liquid crystals and macroscopic assembled fibres  

PubMed Central

Chirality and liquid crystals are both widely expressed in nature and biology. Helical assembly of mesophasic molecules and colloids may produce intriguing chiral liquid crystals. To date, chiral liquid crystals of 2D colloids have not been explored. As a typical 2D colloid, graphene is now receiving unprecedented attention. However, making macroscopic graphene fibres is hindered by the poor dispersibility of graphene and by the lack of an assembly method. Here we report that soluble, chemically oxidized graphene or graphene oxide sheets can form chiral liquid crystals in a twist-grain-boundary phase-like model with simultaneous lamellar ordering and long-range helical frustrations. Aqueous graphene oxide liquid crystals were continuously spun into metres of macroscopic graphene oxide fibres; subsequent chemical reduction gave the first macroscopic neat graphene fibres with high conductivity and good mechanical performance. The flexible, strong graphene fibres were knitted into designed patterns and into directionally conductive textiles. PMID:22146390

Xu, Zhen; Gao, Chao

2011-01-01

345

Recent progress towards centimetric spatial resolution in distributed fibre sensing  

NASA Astrophysics Data System (ADS)

Optical fibre sensors based on stimulated Brillouin scattering have now clearly demonstrated their excellent capability for long-range distributed strain and temperature measurements. The fibre is used as sensing element and a value for temperature and/or strain can be obtained from any point along the fibre. While classical configurations have practically a spatial resolution limited by the phonon lifetime to 1 meter, novel approaches have been demonstrated these past years that can overcome this limit. This can be achieved either by the prior activation of the acoustic wave by a long lasting pre-pumping signal, leading to the optimized configuration using Brillouin echoes, or by probing a classically generated steady acoustic wave using a ultra-short pulse propagating in the orthogonal polarization of a highly birefringent fibre. These novel configurations can offer spatial resolutions in the centimetre range, while preserving the full accuracy on the determination of temperature and strain.

Thévenaz, Luc; Foaleng-Mafang, Stella; Song, Kwang-Yong; Chin, Sanghoon; Beugnot, Jean-Charles; Primerov, Nikolay; Tur, Moshe

2010-09-01

346

Graphene chiral liquid crystals and macroscopic assembled fibres.  

PubMed

Chirality and liquid crystals are both widely expressed in nature and biology. Helical assembly of mesophasic molecules and colloids may produce intriguing chiral liquid crystals. To date, chiral liquid crystals of 2D colloids have not been explored. As a typical 2D colloid, graphene is now receiving unprecedented attention. However, making macroscopic graphene fibres is hindered by the poor dispersibility of graphene and by the lack of an assembly method. Here we report that soluble, chemically oxidized graphene or graphene oxide sheets can form chiral liquid crystals in a twist-grain-boundary phase-like model with simultaneous lamellar ordering and long-range helical frustrations. Aqueous graphene oxide liquid crystals were continuously spun into metres of macroscopic graphene oxide fibres; subsequent chemical reduction gave the first macroscopic neat graphene fibres with high conductivity and good mechanical performance. The flexible, strong graphene fibres were knitted into designed patterns and into directionally conductive textiles. PMID:22146390

Xu, Zhen; Gao, Chao

2011-01-01

347

Fibre Bragg grating sensors for human skin pressure measurements  

Microsoft Academic Search

Summary We demonstrate a low pressure sensor based on a fibre Bragg grating (FBG) for human skin pressure underneath compression stockings. Calibration and comparison with conventional pressure sensors is presented.

Harpreet K Bal; Karan Soin; Patrick McLaughlin; Stephen F Collins; Nicoleta M Dragomir

2010-01-01

348

Exploiting multimode waveguides for pure fibre-based imaging  

PubMed Central

There has been an immense drive in modern microscopy towards miniaturization and fibre-based technology. This has been necessitated by the need to access hostile or difficult environments in situ and in vivo. Strategies to date have included the use of specialist fibres and miniaturized scanning systems accompanied by ingenious microfabricated lenses. Here we present a novel approach for this field by utilizing disordered light within a standard multimode optical fibre for lensless microscopy and optical mode conversion. We demonstrate the modalities of bright- and dark-field imaging and scanning fluorescence microscopy at acquisition rates that allow observation of dynamic processes such as Brownian motion of mesoscopic particles. Furthermore, we show how such control can realize a new form of mode converter and generate various types of advanced light fields such as propagation-invariant beams and optical vortices. These may be useful for future fibre-based implementations of super-resolution or light-sheet microscopy. PMID:22929784

Cizmar, Tomas; Dholakia, Kishan

2012-01-01

349

The Formation and Binding of Gold Nanoparticles onto Wool Fibres  

NASA Astrophysics Data System (ADS)

This paper presents the novel use of nanosize gold with different plasmon resonance colours, as stable colourfast colourants on wool fibres for use in high quality fabrics and textiles. The gold nanoparticles are synthesised by the controlled reduction of Au3+ in the AuCl4- complex to Au0 onto the surface of the wool where they attach to the S in the cystine amino acids in wool keratin proteins. Scanning electronmicroscopy shows the nanoparticles are present on the cuticles of the fibre surface and are concentrated at the edges of these cuticles. EDS analysis shows a strong correlation of Au with S and X-ray photoelectron spectroscopy suggests Au-S bond formation. Hence the nanogold colourants are chemically bound to the wool fibre surface and do not fade as traditional organic dyes do. A range of coloured fibres have been produced.

Johnston, James H.; Burridge, Kerstin A.; Kelly, Fern M.

2009-07-01

350

Equilateral pentagon polarization maintaining photonic crystal fibre with low nonlinearity  

NASA Astrophysics Data System (ADS)

A new pentagon polarization maintaining photonic crystal fibre with low nonlinearity is introduced. The full vector finite element method was used to investigate the distribution and the effective area of modal field, the nonlinear properties, the effective indices of two orthogonal polarization modes and the birefringence of the new PM-PCF effectively. It is found that the birefringence of the new polarization maintaining photonic crystal fibre can easily achieve the order of 10-4, and it can obtain higher birefringence, larger effectively mode-field area and lower nonlinearity than traditional hexagonal polarization maintaining photonic crystal fibre with the same hole pitch, same hole diameter, and same ring number. It is important for sensing and communication applications, especially has potential application for fibre optical gyroscope.

Yang, Han-Rui; Li, Xu-You; Hong, Wei; Hao, Jin-Hui

2012-02-01

351

Graphene chiral liquid crystals and macroscopic assembled fibres  

NASA Astrophysics Data System (ADS)

Chirality and liquid crystals are both widely expressed in nature and biology. Helical assembly of mesophasic molecules and colloids may produce intriguing chiral liquid crystals. To date, chiral liquid crystals of 2D colloids have not been explored. As a typical 2D colloid, graphene is now receiving unprecedented attention. However, making macroscopic graphene fibres is hindered by the poor dispersibility of graphene and by the lack of an assembly method. Here we report that soluble, chemically oxidized graphene or graphene oxide sheets can form chiral liquid crystals in a twist-grain-boundary phase-like model with simultaneous lamellar ordering and long-range helical frustrations. Aqueous graphene oxide liquid crystals were continuously spun into metres of macroscopic graphene oxide fibres; subsequent chemical reduction gave the first macroscopic neat graphene fibres with high conductivity and good mechanical performance. The flexible, strong graphene fibres were knitted into designed patterns and into directionally conductive textiles.

Xu, Zhen; Gao, Chao

2011-12-01

352

Dietary fibre and colon cancer: epidemiologic and experimental evidence.  

PubMed Central

Epidemiologic studies have identified two dietary factors, a relatively high intake of fat and a relatively low intake of fibre, that are associated with colon cancer in humans. However, a recent study has shown a low risk of large bowel cancer in a rural Finnish population with a high dietary intake of fat, but also a high intake of fibre. Observations in humans and studies in animals have indicated that dietary fibre may protect against colon carcinogenesis by binding bile acids in the intestinal tract, by a direct effect on the colonic mucosa and by an indirect effect on the metabolism of carcinogens. The strength of protection varies with the type of fibre. PMID:6254626

Reddy, B S

1980-01-01

353

Transports along paths in Fibre Bundles. I. General Theory  

E-print Network

Transports along path in fibre bundles are axiomatically introduced. Their general functional form and some their simple properties are investigated. The relationships of the transports along paths and lifting of paths are studied.

Bozhidar Z. Iliev

2005-03-01

354

Spraying asymmetry into functional membranes layer-by-layer  

NASA Astrophysics Data System (ADS)

As engineers strive to mimic the form and function of naturally occurring materials with synthetic alternatives, the challenges and costs of processing often limit creative innovation. Here we describe a powerful yet economical technique for developing multiple coatings of different morphologies and functions within a single textile membrane, enabling scientists to engineer the properties of a material from the nanoscopic level in commercially viable quantities. By simply varying the flow rate of charged species passing through an electrospun material during spray-assisted layer-by-layer deposition, individual fibres within the matrix can be conformally functionalized for ultrahigh-surface-area catalysis, or bridged to form a networked sublayer with complimentary properties. Exemplified here by the creation of selectively reactive gas purification membranes, the myriad applications of this technology also include self-cleaning fabrics, water purification and protein functionalization of scaffolds for tissue engineering.

Krogman, Kevin C.; Lowery, Joseph L.; Zacharia, Nicole S.; Rutledge, Gregory C.; Hammond, Paula T.

2009-06-01

355

Failure modes of vacuum plasma spray tungsten coating created on carbon fibre composites under thermal loads  

NASA Astrophysics Data System (ADS)

Vacuum plasma spray tungsten (VPS-W) coating created on a carbon fibre reinforced composite (CFC) was tested under two thermal load schemes in the electron beam facility to examine the operation limits and failure modes. In cyclic ELM-like short transient thermal loads, the VPS-W coating was destroyed sub-layer by sub-layer at 0.33 GW/m 2 for 1 ms pulse duration. At longer single pulses, simulating steady-state thermal loads, the coating was destroyed at surface temperatures above 2700 °C by melting of the rhenium containing multilayer at the interface between VPS-W and CFC. The operation limits and failure modes of the VPS-W coating in the thermal load schemes are discussed in detail.

Hirai, T.; Bekris, N.; Coad, J. P.; Grisolia, C.; Linke, J.; Maier, H.; Matthews, G. F.; Philipps, V.; Wessel, E.

2009-07-01

356

ON FIBRE SPACE STRUCTURES OF A PROJECTIVE IRREDUCIBLE SYMPLECTIC MANIFOLD  

Microsoft Academic Search

In this note, we investigate fibre space structures of a projective irreducible symplectic manifold. We prove that a 2n-cdimensional projective irreducible symplectic manifold admits only an n-dimensional fibration over a Fano variety which has only Q-factorial log-terminal singularities and whose Picard number is one. Moreover we prove that a general fibre is an abelian variety up to finite unramified cover,

Daisuke Matsushita

1999-01-01

357

Polarization insensitive fibre-optic white-light interferometry  

Microsoft Academic Search

Interferometric systems consisting of two tandem interferometers with white-light illumination have been used as optical-fibre remote-sensing systems. Recently, it has been shown that both phase and amplitude of the output signal are significantly affected by externally induced birefringence in the fibre linking the interferometers; in some cases, this may cause total fading of the interference signal. In this letter, a

L. A Ferreira; J. L Santos; F Farahi

1995-01-01

358

Z-Pinch Experiments with Styrofoam Fibres and Plasmajets  

Microsoft Academic Search

Z-pinch plasmas created from fibres are less prone to macroscopic instabilities than predicted by ideal MHD theory. However, solid fibre experiments at the pulseline KALIF (2 MV, 900 kA) gave disappointing results with respect to driver-load coupling and pinch plasma confinement. High power discharges led to current leaks and plasma expansion presumably due to lacking initial conductivity and compressibility. Therefore

S. Stein; G. Decker; W. Kies; P. Röwekamp; G. Ziethen; K. Baumung; H. Bluhm; W. Ratajczak; D. Rusch; J. M. Bayley

1994-01-01

359

Mitigating modulation instability in Brillouin distributed fibre sensors  

NASA Astrophysics Data System (ADS)

A thorough study of the generation of modulation instability (MI) in distributed Brillouin fibre sensors is presented. ASE noise co-propagating with the pump pulses within the MI gain spectrum has been identified to be an important factor seeding modulation instability and reducing its power threshold. The paper describes how optical narrowband filtering reduces the pump depletion resulting from MI, allowing pump pulses to propagate through longer distances in standard optical single-mode fibres.

Soto, Marcelo A.; Alem, Mehdi; Chen, Wei; Thévenaz, Luc

2013-05-01

360

SOLITONS: Nonreciprocal dynamics of pulses in a nonlinear inhomogeneous fibre  

NASA Astrophysics Data System (ADS)

The conditions, under which the nonreciprocity of the frequency modulation rate and pulse duration as well as the spectral nonreciprocity in fibres with different types of inhomogeneity of nonlinearity and group-velocity dispersion appear, are studied for the Gaussian and hyperbolic secant frequency-modulated pulses. Strong compression nonreciprocity is found in fibres with an alternating group-velocity dispersion periodically changing over its length.

Adamova, M. S.; Zolotovskii, Igor'O.; Sementsov, Dmitrii I.

2007-08-01

361

Statistical prediction of fatigue failure of fibre reinforced composite materials  

Microsoft Academic Search

A statistical approach is proposed to evaluate the residual strength and life of unidirectional and angle-ply composite laminates subjected to in-plane tensile cyclic stresses. The method is based on the extension of previous static failure criteria describing independently the fibre failure and matrix failure modes, combined with the statistical nature of fatigue failure of fibre-reinforced composites. The static and fatigue

Xiaoxue Diao; Lin Ye; Yiu-Wing Mai

1995-01-01

362

Hemp fibre reinforced cashew nut shell liquid composites  

Microsoft Academic Search

Hemp fibre bundles were alkalised at concentrations between 0.8 and 8% NaOH and the change in surface morphology was elucidated using scanning electron microscopy. Fibres were tested in tension and the 4 and 6% NaOH treatment resulted in the highest Young's modulus and tensile strength of 65 GPa and 1064 MPa respectively. The Young's modulus and tensile strength of untreated

L. Y. Mwaikambo; M. P. Ansell

2003-01-01

363

IR luminescence in bismuth-doped germanate glasses and fibres  

SciTech Connect

We have studied the optical properties of lightly bismuth doped ({<=}0.002 mol %) germanate glasses prepared in an alumina crucible. The glasses are shown to contain bismuth-related active centres that have been identified previously only in bismuth-doped fibres produced by MCVD. With increasing bismuth concentration in the glasses, their luminescence spectra change markedly, which is attributable to interaction between individual bismuth centres. (optical fibres)

Pynenkov, A A; Firstov, Sergei V; Panov, A A; Firstova, E G; Nishchev, K N; Bufetov, Igor' A; Dianov, Evgenii M

2013-02-28

364

Characterization of Microcellular Foamed PVC\\/Cellulosic-Fibre Composites  

Microsoft Academic Search

A microcellular plastic is a foamed polymer of a cell size in the range of 0.1 to 10 &mgr;m and a cell density in the range of 109 to 1015 cells\\/cm3. Typically, microcellular plastics have been shown to possess superior impact strength, toughness, and fatigue life to solid polymers. Polymer\\/cellulosic-fibre composites make use of cellulosic-fibres as a reinforcing filler in

L. Matuana-Malanda; C. B. Park; J. J. Balatinecz

1996-01-01

365

Characteristics of Fireproofing and Combustion of Multicomponent Fibre Systems  

Microsoft Academic Search

Fireproofing treatment of knitted fabric made of a blend of wool and Spandex or Fenilon fibres with metal-containing flame retardants (sodium tungstate or potassium hexafluorotitanate) increases the oxygen index to 32.8-53%. Incorporation of titanium compounds in blended material increases its carbonizing power, intensifies the dehydration reaction, and reduces heat release in thermolysis. The fireproofed wool fibre in the material acts

M. A. Seredina; M. A. Tyuganova; L. S. Gal'braikh

2001-01-01

366

Optical fibre based humidity sensor using Co-polyaniline clad  

Microsoft Academic Search

A humidity sensor of nanostructure Co dispersed in polyaniline deposited as a clad, having quick response of 8s (20–95%RH) and recovery time of 1min (95–20%RH) on fibre optical waveguide, is reported, in the range of 20–100%RH. The length and thickness of the clad is optimized for better performance on a commercially procured plastic optical fibre whose original cladding is removed.

Anu Vijayan; Madhavi Fuke; Ranjit Hawaldar; Milind Kulkarni; D. Amalnerkar; R. C. Aiyer

2008-01-01

367

Development of high-fruit-dietary-fibre muffins  

Microsoft Academic Search

Following medical recommendations, consumers now demand fibre-fortified food products. The aim of this study was to develop\\u000a muffins in which peach dietary fibre (DF) was added at 2, 3, 4, 5 or 10% levels, substituting up to 32% flour. The products\\u000a were compared to a control muffin (100% flour). It was observed that the moisture of the muffins increased with

N. Grigelmo-Miguel; E. Carreras-Boladeras; O. Martín-Belloso

1999-01-01

368

Fibre Bundles, Jet Manifolds and Lagrangian Theory. Lectures for Theoreticians  

E-print Network

In contrast with QFT, classical field theory can be formulated in a strict mathematical way by treating classical fields as sections of smooth fibre bundles. Addressing to the theoreticians, these Lectures aim to compile the relevant material on fibre bundles, jet manifolds, connections, graded manifolds and Lagrangian theory. They follow the perennial course of lectures on geometric methods in field theory at the Department of Theoretical Physics of Moscow State University.

G. Sardanashvily

2009-08-13

369

FT Raman microscopy of untreated natural plant fibres  

Microsoft Academic Search

The application of FT-Raman microscopy to the non-destructive analysis of natural plant fibres is demonstrated with samples of flax, jute, ramie, cotton, kapok, sisal and coconut fibre. Vibrational assignments are proposed and characteristic features of each material are presented. Samples were not pre-treated chemically before analysis and were used directly from their respective storage collection; the adaptation of the Raman

H. G. M. Edwards; D. W. Farwell; D. Webster

1997-01-01

370

Engineering the morphology of a self-assembling protein fibre  

NASA Astrophysics Data System (ADS)

Biological assemblies provide inspiration for the development of new materials for a variety of applications. Our ability to realize this potential, however, is hampered by difficulties in producing and engineering natural biomaterials, and in designing them de novo. We previously described a self-assembling system comprising two short complementary segments of straight synthetic polypeptides (termed standards in this report). Their interaction results in the formation of long fibres-about 50 nm in diameter-that extend straight and without branching for tens to hundreds of micrometres. Our aim is to influence and, ultimately, to control fibre morphology. Here, we show that the standard peptides can be supplemented with special peptides to effect morphological changes in the fibres. Specifically, we created half-sized subunits of the standard peptides, which were combined to make nonlinear peptides. When mixed with the standard peptides, these nonlinear peptides produced kinked, waved and branched fibres. We related the numbers of these features to the special/standard ratios empirically. Furthermore, the extent and frequency of kinking was altered by changing the standard-fibre background: more kinking was observed in a background of thinner, less-stable fibres. The ability to perform such transformations holds promise for bottom-up assembly and engineering responsive biomimetic materials for applications in surface and tissue engineering.

Ryadnov, Maxim G.; Woolfson, Derek N.

2003-05-01

371

Determinant factor for clearance of ceramic fibres from rat lungs.  

PubMed Central

Deposition, clearance, retention, and durability of inhaled particles from lungs are known to be important factors for induction of pulmonary fibrosis or lung cancer. To study the deposition and clearance of alumina silicate ceramic fibres from the lung, male Wistar rats were exposed to ceramic fibre particles with a mass median aerodynamic diameter (MMAD) of 4.2 micron, for six hours a day, five days a week for two weeks. The average exposure concentration was 20.7 (standard deviation (SD) 4.5) mg/m3. The rats were killed at one day, three months, and six months after the end of exposure, and the fibre numbers and dimensions were measured with a scanning electron microscope. No significant differences in number and geometric mean length of residual ceramic fibres in the lungs were found between the groups. The geometric mean diameter, however, decreased according to the duration of the clearance period. These findings suggest that solubility of fibre contributes most in the clearance of the inhaled ceramic fibres from the lungs. PMID:1554614

Yamato, H; Tanaka, I; Higashi, T; Kido, M

1992-01-01

372

A simplified immunohistochemical classification of skeletal muscle fibres in mouse.  

PubMed

The classification of muscle fibres is of particular interest for the study of the skeletal muscle properties in a wide range of scientific fields, especially animal phenotyping. It is therefore important to define a reliable method for classifying fibre types. The aim of this study was to establish a simplified method for the immunohistochemical classification of fibres in mouse. To carry it out, we first tested a combination of several anti myosin heavy chain (MyHC) antibodies in order to choose a minimum number of antibodies to implement a semi-automatic classification. Then, we compared the classification of fibres to the MyHC electrophoretic pattern on the same samples. Only two anti MyHC antibodies on serial sections with the fluorescent labeling of the Laminin were necessary to classify properly fibre types in Tibialis Anterior and Soleus mouse muscles in normal physiological conditions. This classification was virtually identical to the classification realized by the electrophoretic separation of MyHC. This immunohistochemical classification can be applied to the total area of Tibialis Anterior and Soleus mouse muscles. Thus, we provide here a useful, simple and time-efficient method for immunohistochemical classification of fibres, applicable for research in mouse. PMID:24998919

Kammoun, M; Cassar-Malek, I; Meunier, B; Picard, B

2014-01-01

373

Fire Retardancy of Natural Fibre Reinforced Sheet Moulding Compound  

NASA Astrophysics Data System (ADS)

Due to environmental awareness and economical considerations, natural fibre reinforced polymer composites seem to present a viable alternative to synthetic fibre reinforced polymer composites such as glass fibres. This is a feasibility study to asses the potential application of natural fibre reinforced sheet moulding compound materials (NF-SMC) for the use in building applications, with particular emphases to their reaction to fire. The reinforcing fibres in this study were industrial hemp fibres. The cone calorimeter which asses the fire hazard of materials by Heat Release Rate (HRR) was used, radiant heat fluxes of 25 and 50 kW/m2 were utilised to simulate an ignition source and fully developed room fire conditions respectively. The results acquired here demonstrate that the NF-SMC can compete with current building materials in terms of their fire behaviour. The peak heat release value for the fire retardant (FR) NF-SMC was 176 kW/m2 conversely for a non-FR NF-SMC was 361 kW/m2.

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

2007-07-01

374

The mechanical performance of hybrid phenol-formaldehyde-based composites reinforced with glass and oil palm fibres  

Microsoft Academic Search

Oil palm fibre was hybridised with glass fibre in order to achieve superior mechanical performance. The reinforcing effect of glass in phenol formaldehyde resin is evaluated at various glass fibre loadings. Tensile strength, tensile modulus and flexural strength increase with an increase in fibre loading. However, elongation at break and flexural modulus are found to decrease beyond 40 wt.% fibre

M. S. Sreekala; Jayamol George; M. G. Kumaran; Sabu Thomas

2002-01-01

375

Muscle fibre type distribution of the thoracolumbar and hindlimb regions of horses: relating fibre type and functional role  

PubMed Central

Background Although the majority of equine muscles have a mixed fibre type distribution indicative of diverse functional roles, the predominance of a fibre type can indicate the primary function of a muscle. The deep epaxial musculature has an important role in core spinal stability in humans, reflected as a predominantly muscle fibre type (MFT) I or postural fibre type. The fibre type of the deep epaxial musculature has not been determined in horses. The objective of the study was to determine the MFT distribution in selected muscles of thoracolumbar and hindlimb region of horses. This included deep epaxial and hypaxial muscles that were hypothesised to have a postural stabilising role. A second objective was to examine differences in MFT distribution between horses bred for endurance (Arabian) and sprinting (Quarter horse). Muscle biopsy samples were obtained from selected thoracolumbar and hind limb muscles of 5 Quarter horses, 4 Arabians, and 2 Thoroughbreds. The myosin heavy chain distribution was determined by gel electrophoresis. Mann–Whitney rank test was used to compare the proportional MFT and differences between breeds. Results Mm. sacrocaudalis dorsalis medialis and diaphragm had the highest proportion of MFT-I. The remaining deep epaxial muscles and the hypaxial muscle m. psoas minor had approximately equal MFT I and II proportions. Mm. psoas major, iliocostalis, longissimus dorsi and the hind limb muscles contained mostly MFT-IIX. The fibre type distribution was similar between Arabians and Quarter horses, although Quarter horses had more MFT-IIX fibres in psoas major (P?=?0.02) while Arabians had more MFT-I fibres in m. longissimus dorsi (P?=?0.03). Conclusions The fibre type distribution of the deep epaxial muscles, mm psoas minor and diaphragm varied from approximately equal MFT-I and II proportions to predominantly MFT-I suggesting a postural stabilising role possibly important in core spinal stability. In contrast the fibre type proportions of mm psoas major, iliocostalis, longissimus dorsi and the hind limb muscles were mainly MFT-II suggesting a locomotory role. Knowledge of fibre type distribution in such a clinically important area can direct diagnosis, prevention and treatment of muscular or neuromotor dysfunction. PMID:24468115

2014-01-01

376

An interrogator for fibre Bragg grating sensors using an ultrasonically induced long-period optical fibre grating  

NASA Astrophysics Data System (ADS)

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 sensor output and the ultrasonic frequency is swept, the FBG centre wavelength can be found as the ultrasonic frequency that gives a minimum output. The first half of the paper is devoted to the experimental investigation to reveal the optical transmission characteristics of the U-LPFG. We observed from our experiments that the travelling wave of flexural vibration is successfully excited on the fibre due to the remaining silicone coating at the fibre terminal. The rejection ratio is changed by the ultrasonic vibration amplitude, while the rejection band width depends on the length of the fibre where the vibration is excited. The wide tunable range of 160 nm (from 1490 to 1650 nm) is available for the ultrasonic frequency range of 300 kHz. We introduced several weighted mean methods to improve the accuracy of determining the centre wavelength. For an interrogator of an FBG temperature sensor, 7.4 °C in standard deviation was obtained.

Fukuma, Norimichi; Kubota, Kenji; Nakamura, Kentaro; Ueha, Sadayuki

2006-05-01

377

CARMENES in SPIE 2014. Building a fibre link for CARMENES  

NASA Astrophysics Data System (ADS)

Optical fibres have successfully been used to couple high-resolution spectrographs to telescopes for many years. As they allow the instrument to be placed in a stable and isolated location, they decouple the spectrograph from environmental influences. Fibres also provide a substantial increase in stability of the input illumination of the spectrograph, which makes them a key optical element of the two high-resolution spectrographs of CARMENES. The optical properties of appropriate fibres are investigated, especially their scrambling and focal ratio degradation (FRD) behaviour. In the laboratory the output illumination of various fibres is characterized and different methods to increase the scrambling of the fibre link are tested and compared. In particular, a combination of fibres with different core shapes shows a very good scrambling performance. The near-field (NF) shows an extremely low sensitivity to the exact coupling conditions of the fibre. However, small changes in the far-field (FF) can still be seen. Related optical simulations of the stability performance of the two spectrographs are presented. The simulations focus on the influence of the non-perfect illumination stabilization in the far-field of the fibre on the radial velocity stability of the spectrographs. We use ZEMAX models of the spectrographs to simulate how the barycentres of the spots move depending on the FF illumination pattern and therefore how the radial velocity is affected by a variation of the spectrograph illumination. This method allows to establish a quantitative link between the results of the measurements of the optical properties of fibres on the one hand and the radial velocity precision on the other. The results provide a strong indication that 1ms?1 precision can be reached using a circular-octagonal fibre link even without the use of an optical double scrambler, which has successfully been used in other high-resolution spectrographs. Given the typical throughput of an optical double scrambler of about 75% to 85 %, our solution allows for a substantially higher throughput of the system.

Stürmer, J.; Stahl, O.; Schwab, C.; Seifert, W.; Quirrenbach, A.; Amado, P. J.; Ribas, I.; Reiners, A.; Caballero, J. A.

2014-07-01

378

Fibre optics improving deepwater rov pipeline inspection  

SciTech Connect

Pipeline inspection is a complex test requiring a variety of sensors. The trend in recent times has been to fit, simultaneously, all of the above sensors to a vehicle in order to maximise data collection from the pipeline in a single pass. This data is then processed in real time as the ROV travels the pipeline. Thus, a chart representing all the available data can be made available shortly after completion of a dive. The current generation of ROVs uses umbilicals containing various combinations of power conductors, co-axia and twisted pairs to carry the sensor data. These umbilicals, however, have inherent disadvantages which become apparent as sensor data increase in quantity and complexity. This disadvantage is the incompatibility of required high quality-data being transmitted to the surface and the large amounts of electrical energy demanded by the vehicle. Another disadvantage is the incompatibility between sensor signals in terms of frequency and power. However, to eliminate these problems, and to provide for future developments in ROV technology, the new generation of ROVs utilise fibre-optic conductors, the advantages being that they are immune from electro-magnetic interference, they offer wider band-widths with lower power losses (typically 5 dB or less per km) than conventional copper conductors, and are easier to handle as umbilicals lengthen due to demand for vehicles to reach greater depths. Typically, these new umbilicals will be 1.5 km in length.

McGregor, D.

1983-09-01

379

Adsolubilisation of organic compounds onto collagen fibres.  

PubMed

Adsolubilisation has been defined as the incorporation to solid-water interfaces of molecules that do not adsorb spontaneously to such interfaces, but can be incorporated through an interaction with an adsorbing surfactant molecule. The aim of this work was to study the adsolubilisation of organic molecules with different hydrophobicity on collagen fibres. Hide powder collagen was treated under mild acidic aqueous conditions with an anionic surfactant, sodium dodecylbenzene sulphonate. Thereafter, five different organic molecules, i.e., benzyl alcohol, 2-naphtol, pararosaniline, hexamethylpararosaniline and nonylphenol with 10 mol ethylene oxide were separately applied to the treated collagen in order to study adsolubilisation as a function of their hydrophobicity. It was found that under acidic conditions all molecules were scarcely adsorbed or not adsorbed by the native hide powder collagen. However, all organic molecules, except benzyl alcohol, were adsolubilised if the hide powder collagen was previously treated with the anionic surfactant. The hydrophobicity of the molecules plays an important role in the adsolubilisation phenomenon with the result that the higher the hydrophobicity (nonylphenol with 10 mol ethylene oxide), the higher the adsolubilisation. PMID:20797724

Maldonado, Fernando; Bautista, Elena; Manich, Albert M; Marsal, Agustín

2010-11-15

380

Bismuth-doped optical fibres: A new breakthrough in near-IR lasing media  

SciTech Connect

Recent results demonstrate that bismuth-doped optical fibres have considerable potential as near-IR active lasing media. This paper examines bismuth-doped fibres intended for the fabrication of fibre lasers and optical amplifiers and reviews recent results on the luminescence properties of various types of bismuth-doped fibres and the performance of bismuth-doped fibre lasers and optical amplifiers for the spectral range 1150 - 1550 nm. Problems are discussed that have yet to be solved in order to improve the efficiency of the bismuth lasers and optical amplifiers. (optical fibres, lasers and amplifiers. properties and applications)

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

2012-09-30

381

Behaviour of the crossbridges in stretched or compressed muscle fibres.  

PubMed

The maximum chord of the myosin heads is comparable to the closest surface-to-surface spacing between the myofilaments in a muscle at the slack length. Therefore, when the sarcomere length increases or when the fibre is compressed, the surface-to-surface myofilament spacing becomes lower than the head long axis. We conclude that, in stretched or compressed fibres, some crossbridges cannot attach, owing to steric hindrance. When the amount of compression is limited, this hindrance may be overcome by a tilting of the heads in the plane perpendicular to the filament axes; in this case, there is no consequence as concerns the crossbridge properties. In highly compressed fibres, the crossbridges become progressively hindered and all the crossbridges are hindered for an axis-to-axis spacing representing about 60% of the spacing observed under zero external osmotic pressure. In this case, both the isometric tension and the ATPase activity of the fibre are zero. In fibres stretched up to 3.77 microns (sarcomere length corresponding to the disappearance of the overlap between the thick and the thin filaments), the ratio of hindered crossbridges over the functional crossbridges may be estimated at about 55%. In stretched fibres, a noticeable proportion of crossbridges are sterically hindered and the crossbridges performance (e.g. constants of attachment and detachment) depends on filament spacing, i.e. on sarcomere length. Therefore, we think it is probably impossible to consider the crossbridges as independent force converters, since this idea requires that the crossbridge properties are independent of sarcomere length. In this connection, all the experiments performed on osmotically compressed fibres are of major importance for the understanding of the true mechanisms of muscle contraction. PMID:2632985

Bachouchi, N; Morel, J E

1989-11-21

382

Scanning laser polarimetry - a review.  

PubMed

Glaucoma is a leading cause of irreversible blindness worldwide. Retinal ganglion cells and their axons represent the selective target of the disease. When visual function is still intact on standard automated perimetry and optic disc appearance is suspicious, an early diagnosis may be supported by the identification of a retinal nerve fibre layer (RNFL) defect in the peripapillary area. At present days, computer-based, real-time imaging of the peripapillary RNFL is available through instruments of easy use and with high levels of accuracy and reproducibility. Scanning laser polarimetry is performed by a confocal scanning laser ophthalmoscope with an integrated polarimeter (GDx-VCC). There is a considerable amount of scientific evidence about the role of this imaging technique for glaucoma diagnosis. The aim of this review is to describe the principles of operation, the examination procedure, the clinical role, the results of main diagnostic studies and the future development of the software for the scanning laser polarimetry. PMID:19138311

Da Pozzo, Stefano; Marchesan, Roberta; Ravalico, Giuseppe

2009-01-01

383

Study of the fabrication parameters of large core Yb 2O 3 doped optical fibre through solution doping technique  

NASA Astrophysics Data System (ADS)

Double clad large core Yb 2O 3 doped fibres with core diameter up to 20 ?m have been fabricated by the solution doping technique through deposition of multiple porous core layers. The process parameters have been optimized with respect to the uniform doping of Al 2O 3 and Yb 2O 3 within the large core preform through soaking of the deposited multiple porous layers of fixed SiO 2-P 2O 5 composition with an alcoholic solution of a mixture of suitable strength of AlCl 3·6H 2O and YbCl 3·6H 2O to get the desired low NA around 0.09-0.11. The most critical parameters associated in this process are the deposition temperature with respect to uniform deposition of un-sintered layers of equal thickness with suitable porosity, viscosity of the soaking solution, pre-sintering temperature, proper mixing of the inlet gas mixture as well as proper drying of the thick porous layer after solution soaking process. This investigation will be very useful for development of large core Yb 2O 3 doped laser fibre technology.

Paul, M. C.; Upadhyaya, B. N.; Das, S.; Dhar, A.; Pal, M.; Kher, S.; Dasgupta, K.; Bhadra, S. K.; Sen, R.

2010-03-01

384

Surface acoustic waves for the characterization of BN-coated fibres observed by Brillouin light scattering.  

PubMed

The observation of acoustic phonons located at the surface of uncoated fibres or guided in thin films deposited on fibres by Brillouin light scattering spectroscopy (BLS) is reported. The BLS technique is non-destructive and non-intrusive and is well applicable to non-planar sample geometries. Investigations were carried out on bundles of commercially available carbon fibres, in which a single fibre was 5 microm in diameter. With regard to the detected surface acoustic excitations, each fibre can be considered as an infinite halfspace owing to the large ratio of fibre diameter to wavelength. The shear modulus, which is highly relevant for the intended technical application, was determined by measurement of the Rayleigh mode phase velocity of the uncoated fibres. These fibre bundles were coated with boron nitride (BN) in a continuously driven thermal chemical vapour deposition (CVD) process using trimethyl borate and ammonia as precursors. In comparison to carbon, BN is expected to improve the mechanical properties of fibre-reinforced composites such as fracture toughness at high temperatures. The measured velocity dispersion of the Rayleigh mode of this film-on-substrate system permitted the comparison of the shear stiffness of the carbon fibre and of the BN film material. The results evidence the desired effect of a distinct stiffness reduction of the coated fibre relative to the uncoated fibre in the near-surface region. Additional information can be obtained on the homogeneity of the deposition across the whole fibre bundle. PMID:14963626

Wittkowski, T; Jung, K; Hillebrands, B; Stöckel, S; Weise, K; Marx, G

2004-06-01

385

Optical solitons in graded-index multimode fibres.  

PubMed

Solitons are non-dispersing localized waves that occur in diverse physical settings, including liquids, optical fibres, plasmas and condensed matter. They attract interest owing to their particle-like nature and are useful for applications such as in telecommunications. A variety of optical solitons have been observed, but versions that involve both spatial and temporal degrees of freedom are rare. Optical fibres designed to support multiple transverse modes offer opportunities to study wave propagation in a setting that is intermediate between single-mode fibre and free-space propagation. Here we report the observation of optical solitons and soliton self-frequency shifting in graded-index multimode fibre. These wave packets can be modelled as multicomponent solitons, or as solitons of the Gross-Pitaevskii equation. Solitons in graded-index fibres should enable increased data rates in low-cost telecommunications systems, are pertinent to space-division multiplexing, and can offer a new route to mode-area scaling for high-power lasers and transmission. PMID:23591886

Renninger, W H; Wise, F W

2013-01-01

386

Studies on the fibre surfaces modified with xylan polyelectrolytes.  

PubMed

Xylan was isolated from birch wood chips by using pressurized hot water extraction (PHWE). The extracted xylan was chemically modified yielding three different xylan derivatives (XDs): xylan sulfate (XS), carboxymethyl xylan (CMX) and xylan-4-[N,N,N-trimethylammonium]butyrate chloride (XTMAB). The structure and molecular weight of XDs was determined by using NMR spectroscopy and size exclusion chromatography (SEC). The potential utilization of xylan polyelectrolytes for modifying fibre surfaces was assessed by sorption experiments using bleached pine Kraft pulp as substrate. Polyelectrolyte titration method was chosen for estimating the amount of sorbed XDs onto the fibres. The cationic xylan derivative XTMAB had a strong interaction with fibres while the anionic derivatives did not show any sorption. X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS) were selected as advanced surface analyses for studying the amount of surface anionic groups and the surface distribution of the XTMAB. XPS and polyelectrolyte titration results suggested that the XTMAB is sorbed onto the fibre surfaces. ToF-SIMS imaging showed that XTMAB was evenly distributed on fibre surfaces. PMID:24750860

Vega, B; Petzold-Welcke, K; Fardim, P; Heinze, T

2012-07-01

387

Z-Pinch Experiments with Styrofoam Fibres and Plasmajets  

NASA Astrophysics Data System (ADS)

Z-pinch plasmas created from fibres are less prone to macroscopic instabilities than predicted by ideal MHD theory. However, solid fibre experiments at the pulseline KALIF (2 MV, 900 kA) gave disappointing results with respect to driver-load coupling and pinch plasma confinement. High power discharges led to current leaks and plasma expansion presumably due to lacking initial conductivity and compressibility. Therefore two alternative schemes have been investigated: Solid fibres were replaced by styrofoam fibres with about 1 % solid density and plasmajets of a deuterium-argon mixture. Analyses of the experimental results showed no major differences between styrofoam and solid fibres. However, the plasmajet experiments resulted in significant improvements with respect to the initial discharge behaviour. Unfortunately, severe pinch disruptions about 40 ns after discharge initiation prevented pinch formation and confinement. The high electric field of the pulseline KALIF and the low density of the jet plasma (E/n > 10-15 Vm2) resulted in runaway electrons and plasma erosion rather than in magnetic confinement to the pinch.

Stein, S.; Decker, G.; Kies, W.; Röwekamp, P.; Ziethen, G.; Baumung, K.; Bluhm, H.; Ratajczak, W.; Rusch, D.; Bayley, J. M.

1994-03-01

388

Interdiffusion in short-fibre reinforced hydroxyapatite ceramics.  

PubMed

Sintering in air and hot isostatic pressing are production methods regarded as being capable of producing fibre-reinforced hydroxyapatite ceramics for biomedical applications. These composites may have the advantage of improved mechanical properties and be suitable for applications in areas where there are significant levels of load on the material. The use of pure hydroxyapatite is restricted to those free of dynamical load. Obtaining improved mechanical strength is a question of the bond between the matrix phase and the fibre-reinforcement phase. However, a chemical bond between both phases, indicated by large diffusion zones, might lead to the dehydration of the hydroxyapatite leading to undesired tricalcium phosphate in the matrix resulting in a weakening of the mechanical and biological stability of the composites. Composites with three fibre types, alumina, 316L-stainless steel and titanium were prepared and sintered in air or hot isostatically pressed. A reaction zone was noted around the titanium and stainless steel fibres, but not around the alumina fibres. The reaction zone was larger for stainless steel than titanium. Hot isostatic pressing also reduced the reaction zone markedly compared to sintering in air. PMID:15348692

Knepper, M; Milthorpe, B K; Moricca, S

1998-10-01

389

Tension development in highly stretched vertebrate muscle fibres  

PubMed Central

1. An apparatus is described by which the length of a selected part of an isolated muscle fibre can be held constant, giving isometric conditions, or alternatively its length can be measured while tension is held constant (isotonic). Control can be switched between length and tension so as to carry out afterloaded contractions with a shortening stop. 2. When a part of a fibre with uniform striation spacing is stretched so far that there is presumably no overlap of filaments, the tension developed during an isometric tetanus with this apparatus is very small (not more than 3-5% of the tension developed at optimum length). 3. If the tendon ends are held stationary, a fibre with the same initial length develops a large amount of tension (order of 30-40% of tension at optimum length) with a slow time course. This additional tension is due to shortening of the end parts of the fibre, where the striation spacing is smaller and overlap of filaments still exists. 4. The resistance to elongation of a part of a fibre where there is no overlap is only slightly increased on stimulation. 5. To a first approximation, the results are in good agreement with expectations based on the sliding filament theory. The development of detectable amounts of tension, and of a slight increase of stiffness, on stimulation, are however not expected on the simplest form of this theory; possible explanations are discussed. ImagesFig. 3 PMID:5921535

Gordon, A. M.; Huxley, A. F.; Julian, F. J.

1966-01-01

390

An all-fibre-optic Fourier transform spectrometer  

NASA Astrophysics Data System (ADS)

A novel fibre-optic Fourier transform spectrometer was constructed. The optical retardation between the arms of a Mach - Zehnder-type interferometer made of single-mode optical fibre is modulated by variation of the fibre temperature. Spectra of a multimode laser diode and a broad-band light source were recorded. Frequency shifts within the observed spectra can be explained with the frequency dispersion of the coefficient of the dependence of the refractive index on temperature, 0957-0233/7/11/011/img5. An oversampling scheme utilizing a phase-locked loop circuit was successfully tested. This allows for the acquisition of spectra with shorter wavelength components than the wavelength of the reference laser if a fibre with sufficiently low cut-off wavelength is employed. Thus, the accessible wavelength region may be extended to the near UV using a conventional silica fibre. Coherent averaging of multiple interferograms was successfully applied to enhance the signal-to-noise ratio of interferograms.

Stelzle, Martin; Tuchtenhagen, Jürgen; Rabolt, John F.

1996-11-01

391

Flow velocity tracking using Fibre Bragg Gratings  

NASA Astrophysics Data System (ADS)

Experiments were performed with the objective to obtain the velocity of liquids, e.g. water and oil / water mixtures flowing through a pipe. Experimentally tested flow rates were between 0.75 and 39 m3/h, corresponding to velocities of 0.023 and 1.2 m/s. Temperature disturbances were created by injecting slugs of hot water through a side inlet. The temperature was measured at regular time intervals of 1.2 s by Fibre Bragg Gratings, which were located at 40 equidistant locations at 0.5 m spacing. Hot slug movement was clearly visible in nearly all data sets. The magnitude of the temperature rise (0.1 - 0.2 °C) at that flow rate had the same magnitude as the temperature noise. Travelling temperature waves showed a relatively strong deformation at low rates, due to relatively strong Taylor dispersion occurring at transitional flow (Reynolds number ~ 2500 at the lowest rate). Temperature disturbances travelling down the pipe were tracked by semblance processing of the temperature data taken at 34 locations after the side inlet; the data from 6 locations before the side inlet was not included. Semblance processing is a technique commonly applied in obtaining seismic wave velocities using an equidistant array of receivers, which was applied here for velocity tracking of hot liquid slugs. The best velocity estimates were obtained at flow velocities of 0.13 and 0.28 m/s, typical for a small oil well. Velocity errors were largely within a +/- 10% bandwidth.

Kusters, Roel; van Rooyen, Arthur; van den Handel, Arno; Franzen, André

2005-09-01

392

The role of fibres and the hypodermis in Compositae melanin secretion.  

PubMed

Melanins are dark, insoluble pigments that are resistant to concentrated acids and bleaching by oxidising agents. Phytomelanin (or phytomelan) is present in the seed coat of some Asparagales and in the fruits of some Compositae. In Compositae fruits, melanin is deposited in the schizogenous spaces between the hypodermis and underlying fibrous layer. Phytomelanin in Compositae is poorly understood, and there are only speculations regarding the cells that produce the pigment and the cellular processes involved in the secretion and polymerisation of phytomelanin. This report describes the cellular processes involved in the secretion of phytomelanin in the pericarp of Praxelis diffusa, a species with a structure typical of the family. The ovaries and fruits at different stages were fixed and processed according to the standard methods of studies of light microscopy and transmission electron microscopy. Hypodermal cells have abundant rough endoplasmic reticulum and mitochondria, and the nuclei have chromatin that is less dense than other cells. These characteristics are typical of cells that synthesise protein/amino acids and suggest no carbohydrate secretion. The fibres, however, have a dense cytoplasm rich in the Golgi bodies that are associated with vesicles and smooth endoplasmic reticulum, common characteristics of carbohydrate secretory cells. Our results indicate that the hypodermal cells are not responsible for the secretion of phytomelanin, as previously described in the literature; in contrast, this function is assigned to the adjacent fibres, which have an organisation typical of cells that secrete carbohydrates. PMID:22940570

De-Paula, Orlando Cavalari; Marzinek, Juliana; Oliveira, Denise Maria Trombert; Machado, Silvia Rodrigues

2013-01-01

393

LHCb: The Front-End electronics for the LHCb scintillating fibres detector  

E-print Network

The LHCb detector will be upgraded during the next LHC shutdown in 2018/19. The tracker system will have a major overhaul. Its components will be replaced with new technologies in order to cope with the increased hit occupancy and radiation environment. A detector made of scintillating fibres read out by silicon photomultipliers (SiPM) is studied for this upgrade. Even if this technology has proven to achieve high efficiency and spatial resolution, its integration within a LHC experiment bears new challenges. This detector will consist of 12 planes of 5 to 6 layers of 250 $\\mu$m fibres with an area of 5×6 m$^2$. Its lead to a total of 500k SiPM channels which need to will be read out at 40MHz. This talk gives an overview of the R&D status of the readout board and the PACIFIC chip. The readout board is connected to the SiPM on one side and to the experiment data-acquisition, experimental control system and services on the other side . The PACIFIC chip is a 128 channel ASIC which can be connected to one 12...

Chanal, H; Pillet, N

2014-01-01

394

Excitation block in a nerve fibre model owing to potassium-dependent changes in myelin resistance  

PubMed Central

The myelinated nerve fibre is formed by an axon and Schwann cells or oligodendrocytes that sheath the axon by winding around it in tight myelin layers. Repetitive stimulation of a fibre is known to result in accumulation of extracellular potassium ions, especially between the axon and the myelin. Uptake of potassium leads to Schwann cell swelling and myelin restructuring that impacts the electrical properties of the myelin. In order to further understand the dynamic interaction that takes place between the myelin and the axon, we have modelled submyelin potassium accumulation and related changes in myelin resistance during prolonged high-frequency stimulation. We predict that potassium-mediated decrease in myelin resistance leads to a functional excitation block with various patterns of altered spike trains. The patterns are found to depend on stimulation frequency and amplitude and to range from no block (less than 100 Hz) to a complete block (greater than 500 Hz). The transitional patterns include intermittent periodic block with interleaved spiking and non-spiking intervals of different relative duration as well as an unstable regime with chaotic switching between the spiking and non-spiking states. Intermittent conduction blocks are accompanied by oscillations of extracellular potassium. The mechanism of conductance block based on myelin restructuring complements the already known and modelled block via hyperpolarization mediated by the axonal sodium pump and potassium depolarization. PMID:22419976

Brazhe, A. R.; Maksimov, G. V.; Mosekilde, E.; Sosnovtseva, O. V.

2011-01-01

395

Novel preparation of controlled porosity particle/fibre loaded scaffolds using a hybrid micro-fluidic and electrohydrodynamic technique.  

PubMed

The purpose of this research was to produce multi-dimensional scaffolds containing biocompatible particles and fibres. To achieve this, two techniques were combined and used: T-Junction microfluidics and electrohydrodynamic (EHD) processing. The former was used to form layers of monodispersed bovine serum albumin (BSA) bubbles, which upon drying formed porous scaffolds. By altering the T-Junction processing parameters, bubbles with different diameters were produced and hence the scaffold porosity could be controlled. EHD processing was used to spray or spin poly(lactic-co-glycolic) (PLGA), polymethysilsesquioxane (PMSQ) and collagen particles/fibres onto the scaffolds during their production and after drying. As a result, multifunctional BSA scaffolds with controlled porosity containing PLGA, PMSQ and collagen particles/fibres were obtained. Product morphology was studied by optical and scanning electron microscopy. These products have potential applications in many advanced biomedical, pharmaceutical and cosmetic fields e.g. bone regeneration, drug delivery, cosmetic cream lathers, facial scrubbing creams etc. PMID:25427646

Parhizkar, Maryam; Sofokleous, Panagiotis; Stride, Eleanor; Edirisinghe, Mohan

2014-01-01

396

Hydroxyapatite coating for titanium fibre mesh scaffold enhances osteoblast activity and bone tissue formation.  

PubMed

This study investigated the bone regeneration properties of titanium fibre mesh as a tissue engineering material. A thin hydroxyapatite (HA) coating on the titanium fibre web was created using the developed molecular precursor method without losing the complex interior structure. HA-coated titanium fibre mesh showed apatite crystal formation in vitro in a human osteoblast culture. Titanium fibre mesh discs with or without a thin HA coating were implanted into rat cranial bone defects, and the animals were killed at 2 and 4 weeks. The in vivo experience revealed that the amount of newly formed bone was significantly higher in the HA-coated titanium fibre mesh than in the non-coated titanium fibre mesh 2 weeks after implantation. These results suggest that thin HA coating enhances osteoblast activity and bone regeneration in the titanium fibre mesh scaffold. Thin HA-coating improved the ability of titanium fibre mesh to act as a bone regeneration scaffold. PMID:22513355

Hirota, Makoto; Hayakawa, Tohru; Yoshinari, Masao; Ametani, Akihiro; Shima, Takaki; Monden, Yuka; Ozawa, Tomomichi; Sato, Mitsunobu; Koyama, Chika; Tamai, Naoto; Iwai, Toshinori; Tohnai, Iwai

2012-10-01

397

Dietary fibres in the regulation of appetite and food intake. Importance of viscosity.  

PubMed

Dietary fibres have many functions in the diet, one of which may be to promote control of energy intake and reduce the risk of developing obesity. This is linked to the unique physico-chemical properties of dietary fibres which aid early signalling of satiation and prolonged or enhanced sensation of satiety. Particularly the ability of some dietary fibres to increase viscosity of intestinal contents offers numerous opportunities to affect appetite regulation. Few papers on the satiating effect of dietary fibres include information on the physico-chemical characteristics of the dietary fibres being tested, including molecular weight and viscosity. For viscosity to serve as a proxy for soluble dietary fibres it is essential to have an understanding of individual dietary fibre viscosity characteristics. The goal of this paper is to provide a brief overview on the role of dietary fibres in appetite regulation highlighting the importance of viscosity. PMID:21115081

Kristensen, Mette; Jensen, Morten Georg

2011-02-01

398

Investigation of interfacial interaction between uncoated and coated carbon fibres and the magnesium alloy AZ91.  

PubMed

Unidirectionally reinforced metal-matrix composites with a fibre volume content between 63 and 68% were processed by squeeze casting using T800 H carbon fibres and the magnesium alloy AZ91. The surface of the fibres was prepared by thermal desizing of the fibres or by deposition of a pyrolytic carbon (pyC) coating. Different interfacial conditions could be identified by transmission electron microscopy (TEM) and the single-fibre push-in test. TEM confirmed the formation of needle-like phases at the fibre surface or, for coated fibres, within the pyrolytic carbon coating. During loading by the Vickers type indenter an intense response was observed for composites of coated fibres and the magnesium alloy. This could by caused by stick-slip effects within the pyrolytic carbon coating. PMID:12397483

Dorner-Reisel, A; Nishida, Y; Klemm, V; Nestler, K; Marx, G; Müller, E

2002-10-01

399

Analysis of the film stacking processing parameters for PLLA/flax fibre biocomposites  

E-print Network

such as flax, nettle or hemp fibres combined to a biodegradable matrix is suggested. These composites can the suitability of natural fibres such as flax, hemp, ramie and sisal as reinforcing components [4-6]. Flax

Brest, Université de

400

Peculiarities of the light propagation in semi-infinite fibre arrays  

SciTech Connect

The spatial intensity distribution of radiation propagating in semi-infinite directional coupler arrays with different dependences of coupling constants on the fibre number is studied. (fibre and integrated optical elements and devices)

Khadzhi, P I; Lyakhomskaya, K D; Orlov, O K [T.G. Shevchenko Dnester State University, Tiraspol (Moldova, Republic of)

2006-10-31

401

Environmental friendly method for the extraction of coir fibre and isolation of nanofibre.  

PubMed

The objective of this work was to develop an environmental friendly method for the effective utilization of coir fibre by adopting steam pre-treatment. The retting of the coconut bunch makes strong environmental problems which can be avoided by this method. Chemical characterization of the fibre during each processing stages confirmed the increase of cellulose content from raw (40%) to final steam treated fibres (93%). Morphological and dynamic light scattering analyses of the fibres at different processing stages revealed that the isolation of cellulose nano fibres occur in the final step of the process as an aqueous suspension. FT-IR and XRD analysis demonstrated that the treatments lead to the gradual removal of lignin and hemicelluloses from the fibres. The existence of strong lignin-cellulose complex in the raw coir fibre is proved by its enhanced thermal stability. Steam explosion has been proved to be a green method to expand the application areas of coir fibre. PMID:23399179

Abraham, Eldho; Deepa, B; Pothen, L A; Cintil, J; Thomas, S; John, M J; Anandjiwala, R; Narine, S S

2013-02-15

402

Subchronic inhalation study of stone wool fibres in rats.  

PubMed

Pathology results after subchronic inhalation in rats of three separate fibres representing the new biosoluble high-aluminium low-silica HT type stone wool are given, and the results were compared with the results from a similar study done with the traditional stone wool MMVF21. Male Wistar rats were exposed at one exposure level by nose-only inhalation to well-characterized fibre test atmospheres. The fibres had been size selected to be largely rat respirable. The target dose was an exposure to 150 long fibres/ml (length>20 microm) in each group, and this dose was achieved for all the fibres. The negative control groups were exposed to filtered air. The exposure duration was 6 h/day, 5 days/week for 3 months, with a subsequent non-exposure period lasting 3 months. The rats were killed 1 week after the last exposure and additional post-exposure kills were performed at 1.5 and 3 months to monitor the progression of pulmonary change and fibre numbers in the lung. The assessments included bronchoalveolar lavage fluid (BALF) for evaluation of inflammatory response (e.g. protein content, enzymes, increase in polymorphonuclear leucocytes) and measurement of cell proliferation, assessment of early fibrosis through histological examination and comparison of body weight and lung lobe weights. After exposure of rats to the new biosoluble fibres no biologically significant effects were observed except that a statistically significant increase in lung weight was observed up to 1.5 months post-exposure in all three treatment groups. At 3 months post-exposure, the small increase was no longer significant. The increase in lung weight was still present in the MMVF21 group at the 3 months post-exposure kill. After 3 months exposure, lung retention of long fibres (length>20 microm) varied from 0.4 to 5.2 x 10(6) per lung for the biosoluble fibres. At 3 months post-exposure, the long fibre concentration in the lungs had decreased to 1-7% of this figure. The fibre with the relatively highest biopersistence (RIF41001) showed the highest fibre retention. The retention of the more biopersistent traditional stone wool MMVF21 was 5.7 x 10(6) per rat lung after 3 months exposure and had decreased to 64% of this figure at 3 months post-exposure. There was no clear difference in the bronchoalveolar lavage fluid cell concentration and percentage of cells between MMVF21 and the HT groups. Fibre inhalation caused a significant increase after 3 months in all the biochemical parameters measured in the BALF. Cell proliferation was enhanced at the end of exposure for MMVF21 for all three labelling indices, but only for the bronchiolar epithelium in the RIF41001 group and for alveolar parenchymal cells in the RIF43006-1 group. At the termination of the 3 month exposure period, as well as after 1.5 and 3 month recovery periods, minimal morphological changes were diagnosed in the biosoluble fibre groups. These changes included alveolar macrophage aggregation and/or microgranulomas at the bronchiolar-alveolar junction in the few rats affected. No fibrogenic potential was noted for any of the three fibres. No clear-cut difference between the different biosoluble fibre types was noted. In the MMVF21 group, minimal interstitial fibrosis was observed that gradually decreased after the 1.5 and 3 month non-exposure periods. In this study, the pathological changes found in the lungs of exposed rats were in accordance with the pathology previously reported from full lifespan inhalation studies. This may indicate that for fibres belonging to the man-made vitreous fibres group a well conducted biopersistence study is sufficient to predict possible pathogenic effects for new fibre types. The biological parameters examined in a 90 day study may indicate little additional information to contribute to the prediction of the outcome of carcinogenicity studies. PMID:14990431

Kamstrup, O; Ellehauge, A; Bellmann, B; Chevalier, J; Davis, J M G

2004-03-01

403

Rydberg atoms in hollow-core photonic crystal fibres  

E-print Network

The exceptionally large polarisability of highly excited Rydberg atoms (six orders of magnitude higher than ground-state atoms) makes them of great interest in fields such as quantum optics, quantum computing, quantum simulation and metrology. If however they are to be used routinely in applications, a major requirement is their integration into technically feasible, miniaturised devices. Here we show that a Rydberg medium based on room temperature caesium vapour can be confined in broadband-guiding kagome-style hollow-core photonic crystal fibres. Three-photon spectroscopy performed on a caesium-filled fibre detects Rydberg states up to a principal quantum number of n = 40. Besides small energy level shifts we observe narrow lines confirming the coherence of the Rydberg excitation. Using different Rydberg states and core diameters we study the influence of confinement within the fibre core after different exposure times. Understanding these effects is essential for the successful future development of novel ...

Epple, G; Euser, T G; Joly, N Y; Pfau, T; Russell, P St J; Löw, R

2014-01-01

404

Effect of intratracheal fibres exposure on the rat lung.  

PubMed

The changes in antioxidant status of rat lung after intratracheal instillation of stone-wool and glass fibres were studied. The animals were exposed to 2 or 8 mg of fibres for 4 or 16 weeks, the bronchoalveolar lavage was performed and the activity of superoxide dismutase, glutathione peroxidase and the total amount of glutathione was estimated both in tissue and in cell free fraction of bronchoalveolar lavage and the ascorbic acid was determined in lung tissue. The results showed the higher burden by stone-wool. Most changes were detected in groups exposed to higher dose of fibres for shorter time period, the most sensitive parameter was superoxide dismutase. The lung tissue was studied also by light microscopy and transmission electron microscopy. PMID:16601789

Kováciková, Zuzana; Hurbánková, Marta; Tátrai, Erzsébet; Cerná, Silvia

2005-12-01

405

Implementation and characterization of a fibre-optic colour sensor  

NASA Astrophysics Data System (ADS)

In this paper the implementation of a fibre-optic sensor for colour detection based on reflective colour sensing is proposed. The sensor consists of three plastic optical fibres emitting red, green and blue components and one optical fibre collecting light reflected from the object. Red, green and blue LEDs are excited at different frequencies. In this way detection of the reflected signal is achieved with only one photodetector and three bandpass filters. Bandpass filters are implemented as digital IIR (infinite impulse response) filters on the microcontroller. Results obtained from the proposed sensor are compared with commercial available colour sensors and the results are satisfactory. Analyses of the sensor performance both in RGB and HSV colour space are done. The proposed solution shows that in specific applications by using the HSV model the sensor can be used both as a colour and distance sensor.

Baji?, Jovan S.; Stupar, Dragan Z.; Daki?, Bojan M.; Manojlovi?, Lazo M.; Slankamenac, Miloš P.; Živanov, Miloš B.

2014-09-01

406

Use of chemisorptive fibres to free wastewater from zinc  

SciTech Connect

The authors use the fibrous ion-exchange materials VION KS-3 and VION KN-1 to free wastewater from zinc. It has been shown that at a sulfuric acid content less than 0.5 g/liter and a sodium sulfate content less than 0.2 g/liter in the wastewater, and also in cleaning up neutral waters, it is advisable to use VION KS-3 fibre. It is possible, the authors say, to use VION KN-1 fibre in cleaning up wastewater having a pH of 4 and a considerable salt background. However, in this case, the VION KN-1 fibre should be in the Na-form.

Zverev, M.P.; Egorov, K.K.; Romanova, T.A.; Volkov, L.A.; Zakharova, N.N.

1985-07-01

407

All-Optical Fibre Networks For Coal Mines  

NASA Astrophysics Data System (ADS)

A topic of the paper is fiber-optic integrated network (FOIN) suited to the most hostile environments existing in coal mines. The use of optical fibres for transmission of mine instrumentation data offers the prospects of improved safety and immunity to electromagnetic interference (EMI). The feasibility of optically powered sensors has opened up new opportunities for research into optical signal processing architectures. This article discusses a new fibre-optic sensor network involving a time domain multiplexing(TDM)scheme and optical signal processing techniques. The pros and cons of different FOIN topologies with respect to coal mine applications are considered. The emphasis has been placed on a recently developed all-optical fibre network using spread spectrum code division multiple access (COMA) techniques. The all-optical networks have applications in explosive environments where electrical isolation is required.

Zientkiewicz, Jacek K.

1987-09-01

408

Unravelling the biodiversity of nanoscale signatures of spider silk fibres  

NASA Astrophysics Data System (ADS)

Living organisms are masters at designing outstanding self-assembled nanostructures through a hierarchical organization of modular proteins. Protein-based biopolymers improved and selected by the driving forces of molecular evolution are among the most impressive archetypes of nanomaterials. One of these biomacromolecules is the myriad of compound fibroins of spider silks, which combine surprisingly high tensile strength with great elasticity. However, no consensus on the nano-organization of spider silk fibres has been reached. Here we explore the biodiversity of spider silk fibres, focusing on nanoscale characterization with high-resolution atomic force microscopy. Our results reveal an evolution of the nanoroughness, nanostiffness, nanoviscoelastic, nanotribological and nanoelectric organization of microfibres, even when they share similar sizes and shapes. These features are related to unique aspects of their molecular structures. The results show that combined nanoscale analyses of spider silks may enable the screening of appropriate motifs for bioengineering synthetic fibres from recombinant proteins.

Silva, Luciano P.; Rech, Elibio L.

2013-12-01

409

Fibre positioning concept for the WEAVE spectrograph at the WHT  

NASA Astrophysics Data System (ADS)

WEAVE is the next-generation wide-field optical spectroscopy facility for the William Herschel Telescope (WHT) in La Palma, Canary Islands, Spain. It is a multi-object "pick and place" fibre fed spectrograph with more than one thousand fibres behind a new dedicated 2° prime focus corrector, This is similar in concept to the Australian Astronomical Observatory's 2dF instrument1 with two observing plates, one of which is observing the sky while other is being reconfigured by a robotic fibre positioner. It will be capable of acquiring more than 10000 star or galaxy spectra a night. The WEAVE positioner concept uses two robots working in tandem in order to reconfigure a fully populated field within the expected 1 hour dwell-time for the instrument (a good match between the required exposure times and the limit of validity for a given configuration due to the effects of differential refraction).

Lewis, Ian J.; Dalton, Gavin B.; Brock, Matthew; Gilbert, James; Abrams, Don C.; Aguerri, J. Alfonso L.; Bonifacio, Piercarlo; Middleton, Kevin; Trager, Scott C.

2014-07-01

410

The "Egg of Columbus" for Making the World's Toughest Fibres  

PubMed Central

In this letter we present the “Egg of Columbus” for making fibres with unprecedented toughness: a slider, in the simplest form just a knot, is introduced as frictional element to dissipate additional energy and thus demonstrating the existence of a previously “hidden” toughness. The proof of concept is experimentally realized making the world's toughest fibre, increasing the toughness modulus of a commercial Endumax macroscopic fibre from 44 J/g up to 1070 J/g (and of a zylon microfiber from 20 J/g up to 1400 J/g). The ideal upperbound toughness is expected for graphene, with a theoretical value of ?105 J/g. This new concept, able of maximizing (one fold increment) the structural robustness, could explain the mysterious abundance of knot formations, in spite of their incremental energy cost and topological difficulty, in biological evolved structures, such as DNA strands and proteins. PMID:24695084

Pugno, Nicola M.

2014-01-01

411

Fibre reinforcing by collagen in cartilage and soft connective tissues.  

PubMed

Mechanical support in animals is performed by connective tissues. The soft tissues consist of collagen fibres embedded in a highly hydrated proteoglycan gel. By considering them as fibrous composite materials, a unifying theme can be found to explain their mechanical behaviour in terms of their structure and composition. Interactions between fibres and matrix are essential to their functioning in this way. Calculations are made of the maximum stress transfer per D-period required to enable collagen fibres of a given axial ratio to provide effective reinforcing. Weak non-specific interactions are shown to be sufficient. A mechanical function is proposed for type X collagen in the epiphyseal growth plate on the basis that it modifies and supplements the properties of the type II fibrils. This provides extra reinforcing and, hence, a greater stiffness to the cartilage to compensate for the reduced amount of extracellular matrix. PMID:7838856

Aspden, R M

1994-11-22

412

Development of high tensile strength silicon carbide fibre using an organosilicon polymer precursor  

Microsoft Academic Search

THE high tensile strength SiC fibre developed in our laboratory1-5 is extremely heat-resistant and its wettability by metals is good. Metal-matrix composites reinforced with the SiC fibre should therefore be of practical use. Polycarbosilane, the precursor of the fibre, is synthesised by thermal decomposition under high pressure of poly dimethylsilane in an autoclave. To produce the SiC fibre on an

S. Yajima; Y. Hasegawa; K. Okamura; T. Matsuzawa

1978-01-01

413

Feedback controlled single wavelength interrogation technique for miniature all-silica EFPI fibre optic pressure sensors  

Microsoft Academic Search

This paper proposes a novel technique to stabilise the output wavelength of a tuneable laser source to operate always in the linear range of a miniature all-silica Extrinsic Fabry-Perot Interferometric (EFPI) fibre optic pressure sensor. The technique is based on a fibre optic hybrid sensor, which consists of a miniature all-silica EFPI fibre optic pressure sensor with an incorporated in-Fibre

K. Bremer; E. Lewis; G. Leen; B. Moss; S. Lochmann; I. Mueller

2010-01-01

414

Polyaniline and polyaniline–carbon nanotube composite fibres as battery materials in ionic liquid electrolyte  

Microsoft Academic Search

New battery materials are presented that consist of either a solid polyaniline (PANi) fibre or the same fibre containing carbon nanotubes (CNTs). An ionic liquid ethylmethyl imidazolium bis(trifluoromethanesulfonyl) amide (EMI.TFSA) is used as electrolyte. The electrochemical properties of PANi and PANi\\/CNT fibres are investigated by means of cyclic voltammetry, a.c. impedance and galvanostatic charge–discharge techniques. A PANi fibre with a

C. Y. Wang; V. Mottaghitalab; C. O. Too; G. M. Spinks; G. G. Wallace

2007-01-01

415

Influence of Oven-Drying Temperature on Physicochemical and Functional Properties of Date Fibre Concentrates  

Microsoft Academic Search

Agri-food by-products rich in dietary fibres may be used as feeds and health foods. Owing to its high fibre content, date\\u000a flesh could be useful in human nutrition. It is interesting to study the influence of oven-drying temperatures of date fibre\\u000a concentrates (DFC) on their physicochemical and functional properties for possible use as a potential fibre source in the\\u000a enrichment

Chema Borchani; Souhail Besbes; Manel Masmoudi; Mohamed Ali Bouaziz; Christophe Blecker; Hamadi Attia

416

Impact of corticofugal fibre involvement in subcortical stroke  

PubMed Central

Objective To correlate motor deficit with involvement of corticofugal fibres in patients with subcortical stroke. The descending motor corticofugal fibres originate from the primary motor cortex (M1), dorsal and ventral premotor area (PMdv) and supplementary motor area (SMA). Design Retrospective study. Setting Single tertiary teaching hospital. Participants 57 patients (57% men) with subcortical infarcts on MRI (2009–2011) were included. The mean age was 64.3±14.4?years. Interventions None. Primary and secondary outcome measures National Institute of Health Stroke Scale subscores for arm and leg motor deficit at 90?days. Results An area under the receiver operating characteristics curve (AUC) for the volume of overlap with infarct (and M1/PMdv/SMA fibres) and motor outcome was calculated. The AUC for the association with arm motor deficit from M1 fibres involvement was 0.80 (95% CI 0.66 to 0.94), PMdv was 0.76 (95% CI 0.61 to 0.91) and SMA was 0.73 (95% CI 0.58 to 0.88). The AUC for leg motor deficit from M1 fibres involvement was 0.69 (95% CI 0.52 to 0.85), PMdv was 0.67 (95% CI 0.50 to 0.85), SMA was 0.66 (95% CI 0.48 to 0.84). Conclusions Following subcortical stroke, the correlations between involvement of the corticofugal fibres for upper and lower limbs motor deficit were variable. A poor motor outcome was not universal following subcortical stroke. PMID:24068765

Phan, Thanh G; van der Voort, Sanne; Chen, Jian; Beare, Richard; Ma, Henry; Clissold, Benjamin; Ly, John; Foster, Emma; Thong, Eleanor; Srikanth, Velandai

2013-01-01

417

A fibre Bragg grating stress cell for geotechnical engineering applications  

NASA Astrophysics Data System (ADS)

Existing technology used to measure stress in granular materials is susceptible to water ingress and resulting damage to the electrical components, which limits this technology's use in long-term monitoring of soil structures. The connections of these instruments to readout or recording devices are also fragile and easily damaged. In order to explore the efficacy of fibre optic technology not just as a replacement component, but rather as a material of robust elastic properties, a series of experiments was devised to test the possibility of applying a transverse lateral stress to the fibre and measuring its transformed longitudinal strain. The fibre was inscribed with a 5 mm long Bragg grating and encapsulated in a softer material of high Poisson's ratio in an attempt to enhance the longitudinal strain developed in the fibre. This encapsulated device was then subjected to one-dimensional stress in a standard sand, and the strain in the fibre measured. The experiment showed that satisfactory correlation exists between the measured strain output when converted to an applied stress and the mathematically (and numerically) derived stresses. The fibre/silicone bonding was also modelled and results showed that slippage on that interface could be considered insignificant. In both theoretical and practical applications, this experiment can be regarded as successfully validating the principle of deriving stress from a longitudinal elastic strain measured normal to the applied stress. Hence, development can move towards both miniaturization (for research) and more robust construction (to withstand field conditions). Further research will encompass investigating the response of the cell to water and saturated soil conditions, particularly the device sensitivity to transient stress conditions. In addition, development of the sensor to read the complete three-dimensional state of stress in a soil remains the ultimate goal. South African Provisional Patent Application no 2005/06016.

Legge, T. Francis H.; Swart, Pieter L.; van Zyl, Gideon; Chtcherbakov, Anatoli A.

2006-05-01

418

A fibre optic chemical sensor for the detection of cocaine  

NASA Astrophysics Data System (ADS)

A fibre-optic chemical sensor for the detection of cocaine has been developed, based on a molecularly imprinted polymer (MIP) containing a fluorescein moiety as the signalling group. The fluorescent MIP was formed and covalently attached to the distal end of an optical fibre. The sensor exhibited an increase in fluorescence intensity in response to cocaine in the concentration range of 0 - 500 ?M in aqueous acetonitrile mixtures with good reproducibility over 24 h. Selectivity for cocaine over others drugs has also been demonstrated.

Nguyen, T. Hien; Sun, Tong; Grattan, Kenneth T. V.; Hardwick, S. A.

2010-09-01

419

Steady-state heating of active fibres under optical pumping  

SciTech Connect

We have measured the temperature in the core of rare-earth-doped optical fibres under lasing conditions at high optical pump powers using a fibre Mach - Zehnder interferometer and probe light of wavelength far away from the absorption bands of the active ions. From the observed heating kinetics of the active medium, the heat transfer coefficient on the polymer cladding - air interface has been estimated. The temperature of the active medium is shown to depend on the thermal and optical properties of the polymer cladding. (fiber and integrated optics)

Gainov, V V; Shaidullin, R I; Ryabushkin, Oleg A

2011-07-31

420

Transmission properties of microcoils based on twisted birefringent fibre  

NASA Astrophysics Data System (ADS)

We model the linear transmission properties of birefringent optical microcoil resonators (OMRs) by numerically solving polarisation dependent coupled mode equations. When the fibre is twisted, results show spectral bands where strong coupling between the different polarisations occur. The extinction ratio of certain resonances is also found to be enhanced by the exchange of power into another polarisation. Compared to the standard OMR, the choice of fibre twist and level of birefringence provide additional flexibility in tailoring the OMR spectral properties as needed for applications such as filtering, signal processing and sensing.

Lee, Timothy; Broderick, Neil G. R.; Brambilla, Gilberto

2011-04-01

421

ANFC. Device Driver for Ancor Fibre Channel Adapter  

SciTech Connect

ANFC which interfaces to the Ancor Communications VME CIM 250 Fibre Channel adapter was developed on a Sun Microsystems 3/260 workstation with SUN OS 4.1.3. The VME CIM 250 adapter plugs into the Sun VME bus (with the use of a VME 6U to 9U adapter) providing a Fibre Channel Version 1.6 N-Port functionality. The device driver interfaces to the Sun network I/O system and supports the TCP/IP protocols and a LLNL defined high performance `Direct Channel` protocol.

Abrahams, S. [Lawrence Livermore National Lab., CA (United States)

1993-03-01

422

Position reconstruction in large-area scintillating fibre detectors  

NASA Astrophysics Data System (ADS)

A new analysis procedure has been developed for the large-area scintillating fibre detectors with position-sensitive photomultiplier (PSPM) readout used for heavy ions in the LAND set-up at GSI. It includes gain matching of the PSPM, calibration of the PSPM fibre mask and hit reconstruction. This procedure allows for a quasi-online calibration of this tracking device. It also allows for a precise determination of the position close to the intrinsic detector resolution of 1 mm pitch together with careful treatment of individual event accuracies.

Mahata, K.; Johansson, H. T.; Paschalis, S.; Simon, H.; Aumann, T.

2009-09-01

423

Technological implications of addition of wheat dietary fibre to giant squid ( Dosidicus gigas) surimi gels  

Microsoft Academic Search

The technological effect of wheat dietary fibre was studied in surimi gel products obtained from giant squid (Dosidicus gigas). Three and six percent wheat dietary fibre with different particle sizes was added at the same time as water to maintain similar moisture levels in all samples. Under scanning electronic microscopy (SEM), gel samples with added dietary fibre presented a regular

Isabel Sánchez-Alonso; Maria T. Solas; A. Javier Borderías

2007-01-01

424

Embedded Fibre Bragg Grating Array Sensors in Aluminium Alloy Matrix by Ultrasonic Consolidation  

E-print Network

Embedded Fibre Bragg Grating Array Sensors in Aluminium Alloy Matrix by Ultrasonic Consolidation ABSTRCT Fibre Bragg Grating (FBG) array sensors have been successfully embedded in aluminium alloy matrix sensors have been embedded only in glass and carbon fibre reinforced composite materials and structures

Neirotti, Juan Pablo

425

Sarcomere and filament lengths in passive muscle fibres with wavy myofibrils  

Microsoft Academic Search

Longitudinal compression of isolated skeletal muscle fibres ofRana pipiens caused waves to appear sharply at a critical striation spacing which was slightly less than the slack length measured at the same point. Both slack length and critical length varied between fibres and along the length of one fibre, being shortest near the tendons. The critical length varied from 1.93 to

Lucy M. Brown; H. González-Serratos; A. F. Huxley

1984-01-01

426

Mechanical properties of chemically-treated hemp fibre reinforced sandwich composites  

Microsoft Academic Search

In this study, hemp fabrics were used as reinforcements with polyester resin to form composite skins while short hemp fibres with polyester as a core for making composite sandwich structures. To improve the fibre matrix adhesion properties, alkalisation, silane and acetylation treatments on the fibres surface were carried out. Examinations through fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM),

M. M. Kabir; H. Wang; K. T. Lau; F. Cardona; T. Aravinthan

427

Properties and performances of various hybrid glass\\/natural fibre composites for curved pipes  

Microsoft Academic Search

The aim of the present work was to investigate the hybridization of glass fibres with natural fibres for applications in the piping industry. The natural fibres studied were hemp, flax and kenaf. The pipe selected for the study was a curved fitting (90°) flanged at both ends designed to withstand an internal pressure of 10bar and in the presence of

G. Cicala; G. Cristaldi; G. Recca; G. Ziegmann; A. El-Sabbagh; M. Dickert

2009-01-01

428

Basic properties of ceramic fibres and their effect on insulation performance  

Microsoft Academic Search

This paper reviews the basic properties of ceramic fibres. Individual characteristics such as chemical composition, physical state, temperature stability, chemical stability, fibre diameter and fibre length are discussed. Emphasis is laid on their combined contribution to the properties of the very wide range of product forms commercially available. These properties include thermal conductivity, low weight, heat storage and thermal inertia,

J. Fryatt

1976-01-01

429

SOLITONS AND OPTICAL FIBERS: Self-Q-switched ytterbium-doped cladding-pumped fibre laser  

NASA Astrophysics Data System (ADS)

A self-Q-switched ytterbium-doped double-clad fibre laser is described. A samarium-doped fibre is used as a filter for protecting a pump source. A fibre coupler is employed to obtain a nonlinear feedback. The mechanism of pulse formation in the laser is considered, and the dependence of its output pulse on the coupler parameters is studied.

Grukh, Dmitrii A.; Kurkov, Andrei S.; Razdobreev, I. M.; Fotiadi, A. A.

2002-11-01

430

[Dietary fibre: more than a matter of dietetics. II. Preventative and therapeutic uses].  

PubMed

A nutrition rich in fibre has a preventive effect against constipation, colon diverticulosis, carcinoma of the large bowel and stomach, type 2-diabetes, metabolic syndrome and cardiovascular disease. In case of constipation, diverticulosis and diabetes this effect solely depends on dietary fibre. Regarding carcinomas and cardiovascular diseases, so far unknown factors integrated in or associated with fibre-rich food may also contribute to the preventive effect. Therapy with dietary fibre is indicated for constipation, colon diverticulosis, diarrhea, diabetes, and hypercholesterinemia. The individual dietary fibres differ substance-specifically. Food-integrated dietary fibre such as whole-grain bread, vegetables and fruit have their place in prevention. Dietary fibre preparations such as wheat bran, flax seed or sugar-beet fibre are useful in the treatment of constipation, colon diverticulosis and adiposity. Oat bran is preferentially used in hypercholesterinemia. Purified dietary fibres such as cellulose, guar, psyllium, and beta-glucan have an anti-diabetic, all viscous fibres an anti-lipaemic effect. The therapeutic dosages of dietary fibre preparations are 20-40 g/day and of purified fibres substances 10-20 g/day respectively. PMID:15471177

Trepel, Friedrich

2004-08-31

431

Ris-PhD-11(EN) Properties of hemp fibre polymer  

E-print Network

Risø-PhD-11(EN) Properties of hemp fibre polymer composites -An optimisation of fibre properties Roskilde Denmark Ap