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Sample records for lens fibre cells

  1. Calcium and its localization in human lens fibres: an electron tomographic study

    NARCIS (Netherlands)

    Vanmarle, J.; Jonges, R.; Vrensen, G. F.; Dewolf, A.

    1997-01-01

    The ultrastructural distribution of calcium was studied in human lens fibres with the oxalate pyroantimonate technique. In the intermediate cortex precipitates were found perimembranous and occasionally in the fibre cytoplasm. The improved resolution of electron tomography revealed (a) that the

  2. Lens stem cells may reside outside the lens capsule: an hypothesis

    Directory of Open Access Journals (Sweden)

    Meyer Rita A

    2007-06-01

    Full Text Available Abstract In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors. Historically, the lens has been viewed as a closed system, in which cells at the periphery of the lens epithelium differentiate into fiber cells. Theoretical considerations led us to question whether the intracapsular lens is indeed self-contained. Since stem cells generate tumors and the lens does not naturally develop tumors, we reasoned that lens stem cells may not be present within the capsule. We hypothesize that lens stem cells reside outside the lens capsule, in the nearby ciliary body. Our ideas challenge the existing lens biology paradigm. We begin our discussion with lens background information, in order to describe our lens stem cell hypothesis in the context of published data. Then we present the ciliary body as a possible source for lens stem cells, and conclude by comparing the ocular lens with the corneal epithelium.

  3. Non-essential role for cilia in coordinating precise alignment of lens fibres

    Czech Academy of Sciences Publication Activity Database

    Sugiyama, Y.; Shelley, E.J.; Yoder, B.K.; Kozmik, Zbyněk; May-Simera, H.L.; Beales, P.L.; Lovicu, F.J.; McAvoy, J.W.

    2016-01-01

    Roč. 139, FEB 2016 (2016), s. 10-17 ISSN 0925-4773 R&D Projects: GA ČR GA15-23675S Institutional support: RVO:68378050 Keywords : Lens * Primary cilium * ift88 * Bardet-Biedl Syndrome (BBS) * Planar cell polarity (PCP) Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.333, year: 2016

  4. CARBON-FIBRE-REINFORCED POLYMER PARTS EFFECT ON SPACECRAFT OPTOELECTRONIC MODULE LENS SCATTERING

    Directory of Open Access Journals (Sweden)

    S. S. Kolasha

    2016-01-01

    Full Text Available Spacecraft optoelectronic modules traditionally have aluminum alloy or titanium alloy casing which substantial weight increases fuel consumption required to put them into orbit and, consequently, total cost of the project. Carbon fiber reinforced polymer based composite constructive materials is an efficient solution that allows reducing weight and dimensions of large optoelectronic modules 1,5–3 times and the coefficient of linear thermal expansion 15–20 times if compared with metals. Optical characteristic is a crucial feature of carbon-fibre-reinforced polymer that determines composite material interaction with electromagnetic emission within the optical range. This work was intended to develop a method to evaluate Carbon fiber reinforced polymer optoelectronic modules casing effect on lens scattering by computer simulation with Zemax application software package. Degrees of scattered, reflected and absorbed radiant flux effect on imaging quality are described here. The work included experimental study in order to determine bidirectional reflectance distribution function by goniometric method for LUP-0.1 carbon fabric check test pieces of EDT-69U epoxy binder with EPOFLEX-0.4 glue layer and 5056-3.5-23-A aluminium honeycomb filler. The scattered emission was registered within a hemisphere above the check test piece surface. Optical detection direction was determined with zenith (0º < θ < 90º and azimuth (0º < φ < 180º angles with 10° increment. The check test piece surface was proved to scatter emission within a narrow angle range (approximately 20° with clear directivity. Carbon fiber reinforced polymers was found to feature integrated reflectance coefficient 3 to 4 times greater than special coatings do. 

  5. Adrenergic nerve fibres and mast cells: correlation in rat thymus.

    Science.gov (United States)

    Artico, Marco; Cavallotti, Carlo; Cavallotti, Daniela

    2002-10-21

    The interactions between adrenergic nerve fibres and mast cells (MCs) were studied in the thymus of adult and old rats by morphological methods and by quantitative analysis of images (QAIs). The whole thymus was drawn in adult (12 months old) rats: normal, sympathectomized or electrostimulated. Thymuses from the above-mentioned animals were weighed, measured and dissected. Thymic slices were stained with eosin orange for detection of microanatomical details and with Bodian's method for identification of the whole nerve fibres. Thymic MCs were stained with Astrablau. Histofluorescence microscopy was used for staining of adrenergic nerve fibres. Finally, all morphological results were submitted to the QAIs and statistical analysis of data. Our results suggest that after surgical sympathectomy, the greater part of adrenergic nerve fibres disappear while related MCs appear to show less evident fluorescence and few granules. On the contrary, electrostimulation of the cervical superior ganglion induced an increase in the fluorescence of adrenergic nerve fibres and of related MCs.

  6. c-Myc regulates cell proliferation during lens development.

    Directory of Open Access Journals (Sweden)

    Gabriel R Cavalheiro

    Full Text Available Myc protooncogenes play important roles in the regulation of cell proliferation, growth, differentiation and survival during development. In various developing organs, c-myc has been shown to control the expression of cell cycle regulators and its misregulated expression is detected in many human tumors. Here, we show that c-myc gene (Myc is highly expressed in developing mouse lens. Targeted deletion of c-myc gene from head surface ectoderm dramatically impaired ocular organogenesis, resulting in severe microphtalmia, defective anterior segment development, formation of a lens stalk and/or aphakia. In particular, lenses lacking c-myc presented thinner epithelial cell layer and growth impairment that was detectable soon after its inactivation. Defective development of c-myc-null lens was not caused by increased cell death of lens progenitor cells. Instead, c-myc loss reduced cell proliferation, what was associated with an ectopic expression of Prox1 and p27(Kip1 proteins within epithelial cells. Interestingly, a sharp decrease in the expression of the forkhead box transcription factor Foxe3 was also observed following c-myc inactivation. These data represent the first description of the physiological roles played by a Myc family member in mouse lens development. Our findings support the conclusion that c-myc regulates the proliferation of lens epithelial cells in vivo and may, directly or indirectly, modulate the expression of classical cell cycle regulators in developing mouse lens.

  7. Acoustic Luneburg lens using orifice-type metamaterial unit cells

    Science.gov (United States)

    Park, Choon Mahn; Lee, Sang Hun

    2018-02-01

    A two-dimensional acoustic Luneburg lens that can be easily expanded into a three-dimensional sphere is fabricated. The required spatial distribution of the refractive index for this Luneburg lens is realized using the characteristics of orifice-type metamaterial unit cells. Typical characteristics of the resulting acoustic Luneburg lens, such as its aberration-free performance and capability for antipodal focusing of the lens for the incident plane waves, are investigated through experiments and simulations with the attenuation loss at frequencies that satisfy the homogeneous medium condition of the metamaterial. With the designed metamaterial, we achieved the minimum spot that lies within the classical diffraction limit at the focal point.

  8. Optofluidic realization and retaining of cell-cell contact using an abrupt tapered optical fibre.

    Science.gov (United States)

    Xin, Hongbao; Zhang, Yao; Lei, Hongxiang; Li, Yayi; Zhang, Huixian; Li, Baojun

    2013-01-01

    Studies reveal that there exists much interaction and communication between bacterial cells, with parts of these social behaviors depending on cell-cell contacts. The cell-cell contact has proved to be crucial for determining various biochemical processes. However, for cell culture with relatively low cell concentration, it is difficult to precisely control and retain the contact of a small group of cells. Particularly, the retaining of cell-cell contact is difficult when flows occur in the medium. Here, we report an optofluidic method for realization and retaining of Escherichia coli cell-cell contact in a microfluidic channel using an abrupt tapered optical fibre. The contact process is based on launching a 980-nm wavelength laser into the fibre, E. coli cells were trapped onto the fibre tip one after another, retaining cell-cell contact and forming a highly organized cell chain. The formed chains further show the ability as bio-optical waveguides.

  9. Single fibre and multifibre unit cell analysis of strength and cracking of unidirectional composites

    DEFF Research Database (Denmark)

    Wang, H.W.; Zhou, H.W.; Mishnaevsky, Leon

    2009-01-01

    Numerical simulations of damage evolution in composites reinforced with single and multifibre are presented. Several types of unit cell models are considered: single fibre unit cell, multiple fibre unit cell with one and several damageable sections per fibres, unit cells with homogeneous...... and inhomogeneous interfaces, etc. Two numerical damage models, cohesive elements, and damageable layers are employed for the simulation of the damage evolution in single fibre and multifibre unit cells. The two modelling approaches were compared and lead to the very close results. Competition among the different...... damageable parts in composites (matrix cracks, fibre/matrix interface damage and fibre fracture) was observed in the simulations. The strength of interface begins to influence the deformation behaviour of the cell only after the fibre is broken. In this case, the higher interface layer strength leads...

  10. In situ analysis of cell wall polymers associated with phloem fibre cells in stems of hemp, Cannabis sativa L.

    Science.gov (United States)

    Blake, Anthony W; Marcus, Susan E; Copeland, James E; Blackburn, Richard S; Knox, J Paul

    2008-06-01

    A study of stem anatomy and the sclerenchyma fibre cells associated with the phloem tissues of hemp (Cannabis sativa L.) plants is of interest for both understanding the formation of secondary cell walls and for the enhancement of fibre utility as industrial fibres and textiles. Using a range of molecular probes for cell wall polysaccharides we have surveyed the presence of cell wall components in stems of hemp in conjunction with an anatomical survey of stem and phloem fibre development. The only polysaccharide detected to occur abundantly throughout the secondary cell walls of phloem fibres was cellulose. Pectic homogalacturonan epitopes were detected in the primary cell walls/intercellular matrices between the phloem fibres although these epitopes were present at a lower level than in the surrounding parenchyma cell walls. Arabinogalactan-protein glycan epitopes displayed a diversity of occurrence in relation to fibre development and the JIM14 epitope was specific to fibre cells, binding to the inner surface of secondary cell walls, throughout development. Xylan epitopes were found to be present in the fibre cells (and xylem secondary cell walls) and absent from adjacent parenchyma cell walls. Analysis of xylan occurrence in the phloem fibre cells of hemp and flax indicated that xylan epitopes were restricted to the primary cell walls of fibre cells and were not present in the secondary cell walls of these cells.

  11. The influence of electrospun fibre size on Schwann cell behaviour and axonal outgrowth

    Energy Technology Data Exchange (ETDEWEB)

    Gnavi, S., E-mail: sara.gnavi@unito.it [Department of Clinical and Biological Sciences, University of Torino, Orbassano 10043 (Italy); Neuroscience Institute of the Cavalieri-Ottolenghi Foundation, University of Torino, Orbassano 10043 (Italy); Fornasari, B.E., E-mail: benedettaelena.fornasari@unito.it [Department of Clinical and Biological Sciences, University of Torino, Orbassano 10043 (Italy); Neuroscience Institute of the Cavalieri-Ottolenghi Foundation, University of Torino, Orbassano 10043 (Italy); Tonda-Turo, C., E-mail: chiara.tondaturo@polito.it [Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Politecnico of Torino, Torino 10100 (Italy); Ciardelli, G., E-mail: gianluca.ciardelli@polito.it [Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Politecnico of Torino, Torino 10100 (Italy); CNR-IPCF UOS, Pisa 56124 (Italy); Zanetti, M., E-mail: marco.zanetti@unito.it [Nanostructured Interfaces and Surfaces, Department of Chemistry, University of Torino, Torino 10100 (Italy); Geuna, S., E-mail: stefano.geuna@unito.it [Department of Clinical and Biological Sciences, University of Torino, Orbassano 10043 (Italy); Neuroscience Institute of the Cavalieri-Ottolenghi Foundation, University of Torino, Orbassano 10043 (Italy); Perroteau, I., E-mail: isabelle.perroteau@unito.it [Department of Clinical and Biological Sciences, University of Torino, Orbassano 10043 (Italy)

    2015-03-01

    Fibrous substrates functioning as temporary extracellular matrices can be prepared easily by electrospinning, yielding fibrous matrices suitable as internal fillers for nerve guidance channels. In this study, gelatin micro- or nano-fibres were prepared by electrospinning by tuning the gelatin concentration and solution flow rate. The effect of gelatin fibre diameter on cell adhesion and proliferation was tested in vitro using explant cultures of Schwann cells (SC) and dorsal root ganglia (DRG). Cell adhesion was assessed by quantifying the cell spreading area, actin cytoskeleton organization and focal adhesion complex formation. Nano-fibres promoted cell spreading and actin cytoskeleton organization, increasing cellular adhesion and the proliferation rate. However, both migration rate and motility, quantified by transwell and time lapse assays respectively, were greater in cells cultured on micro-fibres. Finally, there was more DRG axon outgrowth on micro-fibres. These data suggest that the topography of electrospun gelatin fibres can be adjusted to modulate SC and axon organization and that both nano- and micro-fibres are promising fillers for the design of devices for peripheral nerve repair. - Highlights: • Electrospinning used to produce gelatin nano- and micro-fibre matrices. • Nano-fibre matrices promote Schwann cell organization and increase proliferation rate. • Micro-fibre matrices promote Schwann cell migration. • Micro-fibre matrices promote axonal outgrowth.

  12. Spatial pattern of cell geometry and cell-division orientation in zebrafish lens epithelium

    Directory of Open Access Journals (Sweden)

    Toshiaki Mochizuki

    2014-09-01

    Full Text Available Cell proliferation is a key regulator of tissue morphogenesis. We examined cell proliferation and cell division in zebrafish lens epithelium by visualizing cell-cycle phases and nuclear positions, using fluorescent-labeled geminin and histone proteins. Proliferation was low in the anterior region of lens epithelium and higher in the marginal zone anterior to the equator, suggesting that the proliferation zone, called the germinative zone, is formed in zebrafish lens. Interestingly, cell-division orientation was biased longitudinally in the anterior region, shifted from longitudinal to circumferential along the anterior–posterior axis of lens sphere, and was biased circumferentially in the peripheral region. These data suggest that cell-division orientation is spatially regulated in zebrafish lens epithelium. The Hertwig rule indicates that cells tend to divide along their long axes. Orientation of long axes and cell division were biased similarly in zebrafish lens epithelium, suggesting that cell geometry correlates with cell-division orientation. A cell adhesion molecule, E-cadherin, is expressed in lens epithelium. In a zebrafish e-cadherin mutant, the long axes and cell-division orientation were shifted more longitudinally. These data suggest that E-cadherin is required for the spatial pattern of cell geometry and cell-division orientation in zebrafish lens epithelium.

  13. Nanoceria have no genotoxic effect on human lens epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Pierscionek, Barbara K; Yasseen, Akeel A [School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA (United Kingdom); Li, Yuebin; Schachar, Ronald A; Chen, Wei [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Colhoun, Liza M, E-mail: b.pierscionek@ulster.ac.uk, E-mail: weichen@uta.edu [Centre for Vision and Vascular Sciences, School of Medicine, Dentistry and Biomedical Sciences, Queen' s University Belfast, Grosvenor Road, Belfast, BT12 6BA (United Kingdom)

    2010-01-22

    There are no treatments for reversing or halting cataract, a disease of the structural proteins in the eye lens, that has associations with other age-related degenerative conditions such as Alzheimer's disease. The incidence of cataract and associated conditions is increasing as the average age of the population rises. Protein folding diseases are difficult to assess in vivo as proteins and their age-related changes are assessed after extraction. Nanotechnology can be used to investigate protein changes in the intact lens as well as for a potential means of drug delivery. Nanoparticles, such as cerium oxide (CeO{sub 2}) which have antioxidant properties, may even be used as a means of treating cataract directly. Prior to use in treatments, nanoparticle genotoxicity must be tested to assess the extent of any DNA or chromosomal damage. Sister chromatid exchanges were measured and DNA damage investigated using the alkaline COMET assay on cultured human lens epithelial cells, exposed to 5 and 10 {mu}g ml{sup -1} of CeO{sub 2} nanoparticles (nanoceria). Nanoceria at these dosages did not cause any DNA damage or significant increases in the number of sister chromatid exchanges. The absence of genotoxic effects on lens cells suggests that nanoceria, in the doses and exposures tested in this study, are not deleterious to the eye lens and have the potential for use in studying structural alterations, in developing non-surgical cataract treatments and in investigating other protein folding diseases.

  14. Phototoxicity and cytotoxicity of fullerol in human lens epithelial cells

    International Nuclear Information System (INIS)

    Roberts, Joan E.; Wielgus, Albert R.; Boyes, William K.; Andley, Usha; Chignell, Colin F.

    2008-01-01

    The water-soluble, hydroxylated fullerene [fullerol, nano-C 60 (OH) 22-26 ] has several clinical applications including use as a drug carrier to bypass the blood ocular barriers. We have assessed fullerol's potential ocular toxicity by measuring its cytotoxicity and phototoxicity induced by UVA and visible light in vitro with human lens epithelial cells (HLE B-3). Accumulation of nano-C 60 (OH) 22-26 in the cells was confirmed spectrophotometrically at 405 nm and cell viability estimated using MTS and LDH assays. Fullerol was cytotoxic to HLE B-3 cells maintained in the dark at concentrations higher than 20 μM. Exposure to either UVA or visible light in the presence of > 5 μM fullerol-induced phototoxic damage. When cells were pretreated with non-toxic antioxidants: 20 μM lutein, 1 mM N-acetyl cysteine, or 1 mM L-ascorbic acid prior to irradiation, only the singlet oxygen quencher-lutein significantly protected against fullerol photodamage. Apoptosis was observed in lens cells treated with fullerol whether or not the cells were irradiated, in the order UVA > visible light > dark. Dynamic light scattering (DLS) showed that in the presence of the endogenous lens protein α-crystallin, large aggregates of fullerol were reduced. In conclusion, fullerol is both cytotoxic and phototoxic to human lens epithelial cells. Although the acute toxicity of water-soluble nano-C 60 (OH) 22-26 is low, these compounds are retained in the body for long periods, raising concern for their chronic toxic effect. Before fullerols are used to deliver drugs to the eye, they should be tested for photo- and cytotoxicity in vivo

  15. Ionizing radiation response of primary normal human lens epithelial cells.

    Directory of Open Access Journals (Sweden)

    Nobuyuki Hamada

    Full Text Available Whilst the cataractogenic potential of ionizing radiation has been known for over the past 120 years, little is known about radiation responses of lens cells. Our previous work was the first to evaluate the radiosensitivity of lens cells with the clonogenic assay, documenting that the survival of HLEC1 human lens epithelial cells is comparable to that of WI-38 human lung fibroblasts. Moreover, HLEC1 cells were found to contain subsets where irradiation stimulates proliferation or facilitates formation of abortive colonies with fewer cells than human fibroblasts. This study aims to gain insights into these mechanisms. Irradiation of HLEC1 cells with 10% survival dose caused a growth delay but did not reduce viability. HLEC1 cells at high cumulative population doubling level were more susceptible to radiogenic premature senescence than WI-38 cells. Concerning p53 binding protein 1 (53BP1 foci, HLEC1 cells harbored less spontaneous foci but more radiogenic foci than in WI-38 cells, and the focus number returned to spontaneous levels within 48 h postirradiation both in HLEC1 and WI-38. The chemical inhibition of DNA repair kinases ataxia telangiectasia mutated, DNA-dependent protein kinase or both delayed and attenuated the appearance and disappearance of radiogenic 53BP1 foci, increased radiogenic premature senescence and enhanced clonogenic inactivation. The DNA microarray analysis suggested both radiogenic stimulation and inhibition of cell proliferation. Treatment with conditioned medium from irradiated cells did not change growth and the plating efficiency of nonirradiated cells. These results partially explain mechanisms of our previous observations, such that unrepaired or incompletely repaired DNA damage causes a growth delay in a subset of HLEC1 cells without changing viability through induction of premature senescence, thereby leading to clonogenic inactivation, but that growth is stimulated in another subset via as yet unidentified

  16. Do epidermal lens cells facilitate the absorptance of diffuse light?

    Science.gov (United States)

    Brodersen, Craig R; Vogelmann, Thomas C

    2007-07-01

    Many understory plants rely on diffuse light for photosynthesis because direct light is usually scattered by upper canopy layers before it strikes the forest floor. There is a considerable gap in the literature concerning the interaction of direct and diffuse light with leaves. Some understory plants have well-developed lens-shaped epidermal cells, which have long been thought to increase the absorption of diffuse light. To assess the role of epidermal cell shape in capturing direct vs. diffuse light, we measured leaf reflectance and transmittance with an integrating sphere system using leaves with flat (Begonia erythrophylla, Citrus reticulata, and Ficus benjamina) and lens-shaped epidermal cells (B. bowerae, Colocasia esculenta, and Impatiens velvetea). In all species examined, more light was absorbed when leaves were irradiated with direct as opposed to diffuse light. When leaves were irradiated with diffuse light, more light was transmitted and more was reflected in both leaf types, resulting in absorptance values 2-3% lower than in leaves irradiated with direct light. These data suggest that lens-shaped epidermal cells do not aid the capture of diffuse light. Palisade and mesophyll cell anatomy and leaf thickness appear to have more influence in the capture and absorption of light than does epidermal cell shape.

  17. Differential satellite cell density of type I and II fibres with lifelong endurance running in old men

    DEFF Research Database (Denmark)

    Mackey, Abigail; Karlsen, A; Couppé, C

    2014-01-01

    between these variables were determined. RESULTS: In O-Un and O-Tr, type II fibres were smaller and contained fewer satellite cells than type I fibres. However, when expressed relative to fibre area, the difference in satellite cell content between fibre types was eliminated in O-Tr, but not O...... the satellite cell pool and (ii) is associated with a similar density of satellite cells in type I and II fibres despite a failure to preserve the equal fibre type distribution of satellite cells observed in young individuals. Taken together, these data reveal a differential regulation of satellite cell content...

  18. Modulation of lens cell adhesion molecules by particle beams

    Science.gov (United States)

    McNamara, M. P.; Bjornstad, K. A.; Chang, P. Y.; Chou, W.; Lockett, S. J.; Blakely, E. A.

    2001-01-01

    Cell adhesion molecules (CAMs) are proteins which anchor cells to each other and to the extracellular matrix (ECM), but whose functions also include signal transduction, differentiation, and apoptosis. We are testing a hypothesis that particle radiations modulate CAM expression and this contributes to radiation-induced lens opacification. We observed dose-dependent changes in the expression of beta 1-integrin and ICAM-1 in exponentially-growing and confluent cells of a differentiating human lens epithelial cell model after exposure to particle beams. Human lens epithelial (HLE) cells, less than 10 passages after their initial culture from fetal tissue, were grown on bovine corneal endothelial cell-derived ECM in medium containing 15% fetal bovine serum and supplemented with 5 ng/ml basic fibroblast growth factor (FGF-2). Multiple cell populations at three different stages of differentiation were prepared for experiment: cells in exponential growth, and cells at 5 and 10 days post-confluence. The differentiation status of cells was characterized morphologically by digital image analysis, and biochemically by Western blotting using lens epithelial and fiber cell-specific markers. Cultures were irradiated with single doses (4, 8 or 12 Gy) of 55 MeV protons and, along with unirradiated control samples, were fixed using -20 degrees C methanol at 6 hours after exposure. Replicate experiments and similar experiments with helium ions are in progress. The intracellular localization of beta 1-integrin and ICAM-1 was detected by immunofluorescence using monoclonal antibodies specific for each CAM. Cells known to express each CAM were also processed as positive controls. Both exponentially-growing and confluent, differentiating cells demonstrated a dramatic proton-dose-dependent modulation (upregulation for exponential cells, downregulation for confluent cells) and a change in the intracellular distribution of the beta 1-integrin, compared to unirradiated controls. In contrast

  19. Cell-mediated fibre recruitment drives extracellular matrix mechanosensing in engineered fibrillar microenvironments

    Science.gov (United States)

    Baker, Brendon M.; Trappmann, Britta; Wang, William Y.; Sakar, Mahmut S.; Kim, Iris L.; Shenoy, Vivek B.; Burdick, Jason A.; Chen, Christopher S.

    2015-12-01

    To investigate how cells sense stiffness in settings structurally similar to native extracellular matrices, we designed a synthetic fibrous material with tunable mechanics and user-defined architecture. In contrast to flat hydrogel surfaces, these fibrous materials recapitulated cell-matrix interactions observed with collagen matrices including stellate cell morphologies, cell-mediated realignment of fibres, and bulk contraction of the material. Increasing the stiffness of flat hydrogel surfaces induced mesenchymal stem cell spreading and proliferation; however, increasing fibre stiffness instead suppressed spreading and proliferation for certain network architectures. Lower fibre stiffness permitted active cellular forces to recruit nearby fibres, dynamically increasing ligand density at the cell surface and promoting the formation of focal adhesions and related signalling. These studies demonstrate a departure from the well-described relationship between material stiffness and spreading established with hydrogel surfaces, and introduce fibre recruitment as a previously undescribed mechanism by which cells probe and respond to mechanics in fibrillar matrices.

  20. Development of fibre and parenchyma cells in the bamboo Phyllostachys viridi-glaucescens

    CERN Document Server

    Crow, E

    2000-01-01

    The development of the shoot apex and the ontogeny of fibre and parenchyma cells in elongating shoots of the bamboo Phyllostachys viridi-glaucescens (Carr.) Riv. and Riv., seen under the light microscope is described. Fibre cells differentiated from cells of the procambium, whilst the parenchyma cells differentiated from cells of the primary thickening meristem which surround the procambium strands. Three stages of early fibre and parenchyma cell development were identified and these are referred to in subsequent studies of cell wall development. The cytology of developing internodal fibre and parenchyma cells seen under the transmission electron microscope (TEM) is described. There were few ultrastructural features to distinguish the two cell types. Thiery's PATAg test was performed to identify organelles which may be associated with the synthesis of polysaccharides destined for the cell wall. The ultrastructural results are discussed in terms of the process of cell wall deposition. Observations were made of...

  1. Silk-fibronectin protein alloy fibres support cell adhesion and viability as a high strength, matrix fibre analogue

    Science.gov (United States)

    Jacobsen, Matthew M.; Li, David; Gyune Rim, Nae; Backman, Daniel; Smith, Michael L.; Wong, Joyce Y.

    2017-04-01

    Silk is a natural polymer with broad utility in biomedical applications because it exhibits general biocompatibility and high tensile material properties. While mechanical integrity is important for most biomaterial applications, proper function and integration also requires biomaterial incorporation into complex surrounding tissues for many physiologically relevant processes such as wound healing. In this study, we spin silk fibroin into a protein alloy fibre with whole fibronectin using wet spinning approaches in order to synergize their respective strength and cell interaction capabilities. Results demonstrate that silk fibroin alone is a poor adhesive surface for fibroblasts, endothelial cells, and vascular smooth muscle cells in the absence of serum. However, significantly improved cell attachment is observed to silk-fibronectin alloy fibres without serum present while not compromising the fibres’ mechanical integrity. Additionally, cell viability is improved up to six fold on alloy fibres when serum is present while migration and spreading generally increase as well. These findings demonstrate the utility of composite protein alloys as inexpensive and effective means to create durable, biologically active biomaterials.

  2. Trapping and proliferation of target cells on C60fullerene nano fibres.

    Science.gov (United States)

    Iwai, Seiki; Kurosu, Shunji; Sasaki, Hideki; Kato, Kazunori; Maekawa, Toru

    2017-08-01

    The ratio of the surface area to the volume of materials increases in inverse proportion to their size and therefore the surface area of nanostructures and nanomaterials is extremely large compared to that of macroscopic materials of the same volume, thanks to which it is supposed that chemical and biochemical reactions may be greatly enhanced and target molecules and cells may be efficiently trapped on the surface of nanomaterials. It is well known that C 60 molecules are stable both physically and chemically and the affinity of C 60 molecules with biomolecules is rather high. Here, we synthesise fibres composed of C 60 and sulphur and immobilise the surface of the fibres with the primary antibody; i.e., epithelial cell adhesion molecules (anti-EpCAM), to trap target cells. The primary antibody is evenly immobilised on the fibres confirmed by a fluorescent secondary antibody attached to the primary one and then TE2 esophageal and DLD-1 colon cancer cells are successfully trapped by the primary antibody immobilised on the fibres thanks to its high affinity with TE2 and DLD-1 cells, whereas few IM9 B lymphoblast cells are captured on the fibres since the affinity of the primary antibody with IM9 cells is extremely low. Furthermore, those cells trapped by the primary antibody immobilised on the fibres proliferate faster than native cells thanks to the primary antibody acting as a growth factor. The present result suggests that different types of cells can be trapped and grown on nano fibres by immobilising appropriate antibody molecules on the surface of the fibres. Even an extremely small number of cells in sample fluids may be analysed and characterised for the detection of diseases such as cancer in the early stage by trapping and proliferating target cells on the fibres.

  3. Trapping and proliferation of target cells on C60 fullerene nano fibres

    Directory of Open Access Journals (Sweden)

    Seiki Iwai

    2017-08-01

    Full Text Available The ratio of the surface area to the volume of materials increases in inverse proportion to their size and therefore the surface area of nanostructures and nanomaterials is extremely large compared to that of macroscopic materials of the same volume, thanks to which it is supposed that chemical and biochemical reactions may be greatly enhanced and target molecules and cells may be efficiently trapped on the surface of nanomaterials. It is well known that C60 molecules are stable both physically and chemically and the affinity of C60 molecules with biomolecules is rather high. Here, we synthesise fibres composed of C60 and sulphur and immobilise the surface of the fibres with the primary antibody; i.e., epithelial cell adhesion molecules (anti-EpCAM, to trap target cells. The primary antibody is evenly immobilised on the fibres confirmed by a fluorescent secondary antibody attached to the primary one and then TE2 esophageal and DLD-1 colon cancer cells are successfully trapped by the primary antibody immobilised on the fibres thanks to its high affinity with TE2 and DLD-1 cells, whereas few IM9 B lymphoblast cells are captured on the fibres since the affinity of the primary antibody with IM9 cells is extremely low. Furthermore, those cells trapped by the primary antibody immobilised on the fibres proliferate faster than native cells thanks to the primary antibody acting as a growth factor. The present result suggests that different types of cells can be trapped and grown on nano fibres by immobilising appropriate antibody molecules on the surface of the fibres. Even an extremely small number of cells in sample fluids may be analysed and characterised for the detection of diseases such as cancer in the early stage by trapping and proliferating target cells on the fibres.

  4. Solution blow spinning fibres: New immunologically inert substrates for the analysis of cell adhesion and motility.

    Science.gov (United States)

    Paschoalin, Rafaella T; Traldi, Bruna; Aydin, Gülcan; Oliveira, Juliano E; Rütten, Stephan; Mattoso, Luiz H C; Zenke, Martin; Sechi, Antonio

    2017-03-15

    The control of cell behaviour through material geometry is appealing as it avoids the requirement for complex chemical surface modifications. Significant advances in new technologies have been made to the development of polymeric biomaterials with controlled geometry and physico-chemical properties. Solution blow spinning technique has the advantage of ease of use allowing the production of nano or microfibres and the direct fibre deposition on any surface in situ. Yet, in spite of these advantages, very little is known about the influence of such fibres on biological functions such as immune response and cell migration. In this work, we engineered polymeric fibres composed of either pure poly(lactic acid) (PLA) or blends of PLA and polyethylene glycol (PEG) by solution blow spinning and determined their impact on dendritic cells, highly specialised cells essential for immunity and tolerance. We also determined the influence of fibres on cell adhesion and motility. Cells readily interacted with fibres resulting in an intimate contact characterised by accumulation of actin filaments and focal adhesion components at sites of cell-fibre interactions. Moreover, cells were guided along the fibres and actin and focal adhesion components showed a highly dynamic behaviour at cell-fibre interface. Remarkably, fibres did not elicit any substantial increase of activation markers and inflammatory cytokines in dendritic cells, which remained in their immature (inactive) state. Taken together, these findings will be useful for developing new biomaterials for applications in tissue engineering and regenerative medicine. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  5. Association of the nuclear matrix component NuMA with the Cajal body and nuclear speckle compartments during transitions in transcriptional activity in lens cell differentiation.

    Science.gov (United States)

    Gribbon, Chris; Dahm, Ralf; Prescott, Alan R; Quinlan, Roy A

    2002-10-01

    The transcriptional status of cells can be deduced from the staining pattern of various nuclear markers such as the Cajal body, nucleolus and nuclear speckles. In this study we have used these markers to correlate transcriptional status with cell differentiation in the lens. As a closed system with no cell loss and with each stage being spatially preserved, it is particularly well suited to such studies. To confirm that the nuclear markers in lens cells follow the same trends as in other cells, primary bovine lens epithelial cells were cultured and then treated with actinomycin D to inhibit transcription. This reduced the Cajal body markers to one or two foci per nucleus and the nucleoli became compacted as revealed by fibrillarin staining. The nuclear speckles, containing snRNPs (e.g. Sm) and the splicing factor, SC35, also became larger and more numerous while the signal for trimethylguanine (TMG) decreased suggesting a role hierarchy for the various speckle factors during transcriptional shutdown. The signal for survival of motor neurones gene product (SMN) also decreased at this point. In the lens epithelium, postmitotic cells near the equatorial region had one or two Cajal bodies per nucleus, indicating these cells had only basal levels of transcription. Sm was also present as large foci in these cells. Interestingly, both the speckles and Cajal bodies were NuMA-positive in these post-mitotic cells. At the epithelial-fibre cell transition, Cajal body number increased, while their size decreased indicative of increased transcriptional activity. Fibrillarin adopted the open floret pattern indicating increased transcriptional activity. The nuclear speckles adopted a more diffuse nucleoplasmic pattern, although some spots were still observed. All NuMA colocalisation with the Cajal bodies and nuclear speckles was lost at this stage of lens cell differentiation. Transcriptional shutdown occurs at a later stage in fibre cell differentiation, prior to programmed

  6. Does dietary fibre stimulate intestinal epithelial cell proliferation in germ free rats?

    OpenAIRE

    Goodlad, R A; Ratcliffe, B; Fordham, J P; Wright, N A

    1989-01-01

    The aim of the present experiment was to investigate the role of hind gut fermentation in the proliferative response of the intestinal epithelium to dietary fibre. We have previously shown that refeeding starved rats with an elemental diet supplemented with fermentable dietary fibre (but not inert bulk) is capable of stimulating intestinal epithelial cell proliferation throughout the gastrointestinal tract. Three groups of 10 germ free (GF) rats and three groups of 10 conventional (CV) rats, ...

  7. Pax6- and Six3-mediated induction of lens cell fate in mouse and human ES cells.

    Directory of Open Access Journals (Sweden)

    Raymond M Anchan

    Full Text Available Embryonic stem (ES cells provide a potentially useful in vitro model for the study of in vivo tissue differentiation. We used mouse and human ES cells to investigate whether the lens regulatory genes Pax6 and Six3 could induce lens cell fate in vitro. To help assess the onset of lens differentiation, we derived a new mES cell line (Pax6-GFP mES that expresses a GFP reporter under the control of the Pax6 P0 promoter and lens ectoderm enhancer. Pax6 or Six3 expression vectors were introduced into mES or hES cells by transfection or lentiviral infection and the differentiating ES cells analyzed for lens marker expression. Transfection of mES cells with Pax6 or Six3 but not with other genes induced the expression of lens cell markers and up-regulated GFP reporter expression in Pax6-GFP mES cells by 3 days post-transfection. By 7 days post-transfection, mES cell cultures exhibited a>10-fold increase over controls in the number of colonies expressing γA-crystallin, a lens fiber cell differentiation marker. RT-PCR and immunostaining revealed induction of additional lens epithelial or fiber cell differentiation markers including Foxe3, Prox1, α- and β-crystallins, and Tdrd7. Moreover, γA-crystallin- or Prox1-expressing lentoid bodies formed by 30 days in culture. In hES cells, Pax6 or Six3 lentiviral vectors also induced lens marker expression. mES cells that express lens markers reside close to but are distinct from the Pax6 or Six3 transduced cells, suggesting that the latter induce nearby undifferentiated ES cells to adopt a lens fate by non-cell autonomous mechanisms. In sum, we describe a novel mES cell GFP reporter line that is useful for monitoring induction of lens fate, and demonstrate that Pax6 or Six3 is sufficient to induce ES cells to adopt a lens fate, potentially via non-cell autonomous mechanisms. These findings should facilitate investigations of lens development.

  8. Taurine Protects Lens Epithelial Cells Against Ultraviolet B-Induced Apoptosis.

    Science.gov (United States)

    Dayang, Wu; Dongbo, Pang

    2017-10-01

    The massive uptake of compatible osmolytes is a self-protective response shared by lens exposed to hypertonic stress and ultraviolet stress. This study aimed to investigate the protective effects of taurine against ultraviolet B-induced cytotoxicity in the lens epithelial cells. Real-time PCR was used to measure osmolytes transport. Radioimmunoassay was used to measure osmolytes uptake. Cell counting kit-8 assays were used to measure cellular viability. Flow cytometry analysis was used to measure apoptosis level. Compared with normotonic stress, hypertonic stress-induced osmolytes uptake into the lens epithelial cells such as betaine, myoinositol and taurine. UVB exposure increased osmolytes transporter mRNA expression together with osmolytes uptake. Moreover, taurine suppressed UVB-induced cell apoptosis in the lens epithelial cells significantly. The effect of compatible osmolyte taurine on cell survival rate may play an important role in cell resistance and adaption to UVB exposure.

  9. Myo/Nog cells: targets for preventing the accumulation of skeletal muscle-like cells in the human lens.

    Directory of Open Access Journals (Sweden)

    Jacquelyn Gerhart

    Full Text Available Posterior capsule opacification (PCO is a vision impairing condition that arises in some patients following cataract surgery. The fibrotic form of PCO is caused by myofibroblasts that may emerge in the lens years after surgery. In the chick embryo lens, myofibroblasts are derived from Myo/Nog cells that are identified by their expression of the skeletal muscle specific transcription factor MyoD, the bone morphogenetic protein inhibitor Noggin, and the epitope recognized by the G8 monoclonal antibody. The goal of this study was to test the hypothesis that depletion of Myo/Nog cells will prevent the accumulation of myofibroblasts in human lens tissue. Myo/Nog cells were present in anterior, equatorial and bow regions of the human lens, cornea and ciliary processes. In anterior lens tissue removed by capsulorhexis, Myo/Nog cells had synthesized myofibroblast and skeletal muscle proteins, including vimentin, MyoD and sarcomeric myosin. Alpha smooth muscle actin (α-SMA was detected in a subpopulation of Myo/Nog cells. Areas of the capsule denuded of epithelial cells were surrounded by Myo/Nog cells. Some of these cell free areas contained a wrinkle in the capsule. Depletion of Myo/Nog cells eliminated cells expressing skeletal muscle proteins in 5-day cultures but did not affect cells immunoreactive for beaded filament proteins that accumulate in differentiating lens epithelial cells. Transforming growth factor-betas 1 and 2 that mediate an epithelial-mesenchymal transition, did not induce the expression of skeletal muscle proteins in lens cells following Myo/Nog cell depletion. This study demonstrates that Myo/Nog cells in anterior lens tissue removed from cataract patients have undergone a partial differentiation to skeletal muscle. Myo/Nog cells appear to be the source of skeletal muscle-like cells in explants of human lens tissue. Targeting Myo/Nog cells with the G8 antibody during cataract surgery may reduce the incidence of PCO.

  10. Corneal cell adhesion to contact lens hydrogel materials enhanced via tear film protein deposition.

    Directory of Open Access Journals (Sweden)

    Claire M Elkins

    Full Text Available Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS, borate buffered saline (BBS, or Sensitive Eyes Plus Saline Solution (Sensitive Eyes, either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.

  11. Vitreous Humor Changes Expression of Iron-Handling Proteins in Lens Epithelial Cells

    Science.gov (United States)

    Goralska, Malgorzata; Fleisher, Lloyd N.; McGahan, M. Christine

    2017-01-01

    Purpose In humans, vitrectomy is associated with development of nuclear cataracts. Iron catalyzes free radical formation causing oxidative damage, which is implicated in cataract formation. This study was designed to determine if vitreous humor, which can initiate differentiation of lens epithelial cells, would have an effect on iron-handling proteins. Methods Cultured canine lens epithelial cells were treated with collected canine vitreous humor. Lysates of treated and control cells were separated by SDS-PAGE. Ferritin H- and L-chains, transferrin receptor 1, and aquaporin 0 were immunodetected and quantitated with specific antibodies. Morphologic changes in treated cells were assessed. Results Treatment of lens epithelial cells with a 33% (vol/vol) solution of vitreous humor changed the morphology of lens cells and induced expression of aquaporin 0, a marker of fiber cell differentiation that was undetectable in control cells. Treatment did not modify the size of iron-handling proteins but significantly increased content of ferritin from 2.9- to 8.8-fold over control and decreased levels of transferrin receptor by 37% to 59%. Conclusions Vitreous humor may significantly limit iron uptake by transferrin/transferrin receptor pathway, and by increasing ferritin levels could profoundly increase the iron-storage capacity of ferritin in lens cells. Vitreous humor may play a significant protective role against iron-catalyzed oxidative damage of lens epithelial cells and therefore in the formation of cataracts. PMID:28245299

  12. Mechanism research of miR-181 regulating human lens epithelial cell apoptosis

    Directory of Open Access Journals (Sweden)

    Yu Qin

    2015-05-01

    Full Text Available AIM: To investigate the expression of miR-181 in the lens tissue of cataract and the regulating mechanism of miR-181 on apoptosis of human lens epithelial cell.METHODS:Real time q-PCR was used to measure the expression of miR-181 in the anterior lens capsules of age-related cataract and human lens epithelial cell apoptosis model. miR-181 mimic and inhibitor were transfected using Lipofectamine 2 000 to regulate the expression of miR-181, and then Real time q-PCR was used to verify transfection efficiency. Flow cytometry was used to detect the change of cell apoptosis rate. RESULTS: Compared with control group, the expression of miR-181 was significantly higher in both the anterior lens capsules of age-related cataract and human lens epithelial cell apoptosis model; the relative expression of miR-181 in lens epithelial cells transfected with miR-181 mimic was increased, whereas decreased in cells transfected with miR-181 inhibitor; the apoptosis rate of cells transfected with miR-181 mimic was increased, while reduced in miR-181 inhibitor group. Each result was statistically significant(PCONCLUSION: High expression of miR-181 is detected in anterior lens capsule of age-related cataract. miR-181 might play a certain role in the pathogenesis of cataract via promoting human lens epithelial cell apoptosis. miR-181 probably becomes a new approach for the nonoperative treatment of cataract, but the concrete mechanism still needs to be further studied.

  13. Polypyrrole/Co-tetraphenylporphyrin modified carbon fibre paper as a fuel cell electrocatalyst of oxygen reduction

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Weimin; Chen, Jun; Wagner, Pawel; Wallace, Gordon G. [ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, Wollongong NSW 2522 (Australia); Swiegers, Gerhard F. [CSIRO Molecular and Health Technologies, Bag 10, Clayton VIC 3169 (Australia)

    2008-04-15

    A thin-layer of polypyrrole (PPy) film, immobilized with neutral 5,10,15,20-tetraphenylporphyrinato cobalt (II) (Co-TPP), was successfully and uniformly deposited onto mesoporous carbon fibre paper (CFP) via vapor-phase polymerization. The resulting PPy/Co-TPP-modified carbon fibre paper (PPy/Co-TPP-CFP) electrode was characterized by cyclic voltammetry, SEM and EDX-ray mapping. Its electrochemical stability and long-term electrocatalytic performance were investigated in a half-fuel cell testing system. The electrode displayed significant electrocatalytic performance for oxygen reduction at 0.0 V (vs. Ag/AgCl), with notable long-term stability. (author)

  14. The status of intercellular junctions in established lens epithelial cell lines.

    Science.gov (United States)

    Dave, Alpana; Craig, Jamie E; Sharma, Shiwani

    2012-01-01

    Cataract is the major cause of vision-related disability worldwide. Mutations in the crystallin genes are the most common known cause of inherited congenital cataract. Mutations in the genes associated with intercellular contacts, such as Nance-Horan Syndrome (NHS) and Ephrin type A receptor-2 (EPHA2), are other recognized causes of congenital cataract. The EPHA2 gene has been also associated with age-related cataract, suggesting that intercellular junctions are important in not only lens development, but also in maintaining lens transparency. The purpose of this study was to analyze the expression and localization of the key cell junction and cytoskeletal proteins, and of NHS and EPHA2, in established lens epithelial cell lines to determine their suitability as model epithelial systems for the functional investigation of genes involved in intercellular contacts and implicated in cataract. The expression and subcellular localization of occludin and zona occludens protein-1 (ZO-1), which are associated with tight junctions; E-cadherin, which is associated with adherence junctions; and the cytoskeletal actin were analyzed in monolayers of a human lens epithelial cell line (SRA 01/04) and a mouse lens epithelial cell line (αTN4). In addition, the expression and subcellular localization of the NHS and EPHA2 proteins were analyzed in these cell lines. Protein or mRNA expression was respectively determined by western blotting or reverse transcription-polymerase chain reaction (RT-PCR), and localization was determined by immunofluorescence labeling. Human SRA 01/04 and mouse αTN4 lens epithelial cells expressed either the proteins of interest or their encoding mRNA. Occludin, ZO-1, and NHS proteins localized to the cellular periphery, whereas E-cadherin, actin, and EPHA2 localized in the cytoplasm in these cell lines. The human SRA 01/04 and mouse αTN4 lens epithelial cells express the key junctional proteins. The localization patterns of these proteins suggest that

  15. Optimising cell aggregate expansion in a perfused hollow fibre bioreactor via mathematical modelling.

    KAUST Repository

    Chapman, Lloyd A C

    2014-08-26

    The need for efficient and controlled expansion of cell populations is paramount in tissue engineering. Hollow fibre bioreactors (HFBs) have the potential to meet this need, but only with improved understanding of how operating conditions and cell seeding strategy affect cell proliferation in the bioreactor. This study is designed to assess the effects of two key operating parameters (the flow rate of culture medium into the fibre lumen and the fluid pressure imposed at the lumen outlet), together with the cell seeding distribution, on cell population growth in a single-fibre HFB. This is achieved using mathematical modelling and numerical methods to simulate the growth of cell aggregates along the outer surface of the fibre in response to the local oxygen concentration and fluid shear stress. The oxygen delivery to the cell aggregates and the fluid shear stress increase as the flow rate and pressure imposed at the lumen outlet are increased. Although the increased oxygen delivery promotes growth, the higher fluid shear stress can lead to cell death. For a given cell type and initial aggregate distribution, the operating parameters that give the most rapid overall growth can be identified from simulations. For example, when aggregates of rat cardiomyocytes that can tolerate shear stresses of up to 0:05 Pa are evenly distributed along the fibre, the inlet flow rate and outlet pressure that maximise the overall growth rate are predicted to be in the ranges 2.75 x 10(-5) m(2) s(-1) to 3 x 10(-5) m(2) s(-1) (equivalent to 2.07 ml min(-1) to 2.26 ml min(-1)) and 1.077 x 10(5) Pa to 1.083 x 10(5) Pa (or 15.6 psi to 15.7 psi) respectively. The combined effects of the seeding distribution and flow on the growth are also investigated and the optimal conditions for growth found to depend on the shear tolerance and oxygen demands of the cells.

  16. α-Crystallin localizes to the leading edges of migrating lens epithelial cells

    International Nuclear Information System (INIS)

    Maddala, Rupalatha; Vasantha Rao, P.

    2005-01-01

    α-crystallin (αA and αB) is a major lens protein, which belongs to the small heat-shock family of proteins and binds to various cytoskeletal proteins including actin, vimentin and desmin. In this study, we investigated the cellular localization of αA and αB-crystallins in migrating epithelial cells isolated from porcine lens. Immunofluorescence localization and confocal imaging of αB-crystallin in confluent and in migrating subconfluent cell cultures revealed a distinct pattern of subcellular distribution. While αB-crystallin localization was predominantly cytoplasmic in confluent cultures, it was strongly localized to the leading edges of cell membrane or the lamellipodia in migrating cells. In accordance with this pattern, we found abundant levels of αB-crystallin in membrane fractions compared to cytosolic and nuclear fractions in migrating lens epithelial cells. αA-crystallin, which has 60% sequence identity to αB-crystallin, also exhibited a distribution profile localizing to the leading edge of the cell membrane in migrating lens epithelial cells. Localization of αB-crystallin to the lamellipodia appears to be dependent on phosphorylation of residue serine-59. An inhibitor of p38 MAP kinase (SB202190), but not the ERK kinase inhibitor PD98059, was found to diminish localization of αB-crystallin to the lamellipodia, and this effect was found to be associated with reduced levels of Serine-59 phosphorylated αB-crystallin in SB202190-treated migrating lens epithelial cells. αB-crystallin localization to the lamellipodia was also altered by the treatment with RGD (Arg-Ala-Asp) peptide, dominant negative N17 Rac1 GTPase, cytochalasin D and Src kinase inhibitor (PP2), but not by the Rho kinase inhibitor Y-27632 or the myosin II inhibitor, blebbistatin. Additionally, in migrating lens epithelial cells, αB-crystallin exhibited a clear co-localization with the actin meshwork, β-catenin, WAVE-1, a promoter of actin nucleation, Abi-2, a component of WAVE

  17. The protective effect of resveratrol on human lens epithelial cells against ultraviolet-induced apoptosis

    Directory of Open Access Journals (Sweden)

    Xue - Fang Chen

    2013-06-01

    Full Text Available AIM: To investigate the protective effect of resveratrol on human lens epithelial cells against ultraviolet-induced apoptosis. METHODS:Subcultured human lens epithelial cell line, ultraviolet induced cell apoptosis, 20μmol/L resveratrol pretreated cell, the indicators change was observed: rate of apoptosis was detected by flow cytometry and apoptosis-related factors of caspses-3 and caspase-9 were detected by colorimetric detection, ultrastructure changes were observed under transmission electron microscope. RESULTS: Flow cytometry instrument testing found that resveratrol can suppress the apoptosis induced by ultraviolet irradiation, caspses-3 and caspase-9 content in positive control group were significantly higher than that of the negative control group at the same time period, the difference was statistically significant(P<0.05; caspses-3 and caspase-9 content in experimental group were lower than that in the positive control group at the same time, the difference was statistically significant(P<0.05. In addition, the damage of human lens epithelial cells was alleviated with the incubation time of resveratrol elongated. CONCLUSION:Resveratrol may inhibit ultraviolet-induced apoptosis of human lens epithelial cells, it has preventive function against radioactive cataract, and it can provide reliable evidence for pursuing effective medicine to prevent and treat cataract.

  18. Spatial distributions of AQP5 and AQP0 in embryonic and postnatal mouse lens development

    Science.gov (United States)

    Petrova, Rosica S.; Schey, Kevin L.; Donaldson, Paul J.; Grey, Angus C.

    2015-01-01

    The expression of the water channel protein aquaporin (AQP)-5 in adult rodent and human lenses was recently reported using immunohistochemistry, molecular biology, and mass spectrometry techniques, confirming a second transmembrane water channel that is present in lens fibre cells in addition to the abundant AQP0 protein. Interestingly, the sub-cellular distribution and level of post-translational modification of both proteins changes with fibre cell differentiation and location in the adult rodent lens. This study compares the sub-cellular distribution of AQP0 and AQP5 during embryonic and postnatal fibre cell development in the mouse lens to understand how the immunolabelling patterns for both AQPs observed in adult lens are first established. Immunohistochemistry was used to map the cellular and sub-cellular distribution of AQP5 and AQP0 throughout the lens in cryosections from adult (6 weeks to 8 months) and postnatal (0-2 weeks) mouse lenses and in sections from paraffin embedded mouse embryos (E10-E19). All sections were imaged by fluorescence confocal microscopy. Using antibodies directed against the C-terminus of each AQP, AQP5 was abundantly expressed early in development, being found in the cytoplasm of cells of the lens vesicle and surrounding tissues (E10), while AQP0 was detected later (E11), and only in the membranes of elongating primary fibre cells. During the course of subsequent embryonic and postnatal development the pattern of cytoplasmic AQP5 and membranous AQP0 labelling was maintained until postnatal day 6 (P6). From P6 AQP5 labelling became progressively more membranous initially in the lens nucleus and then later in all regions of the lens, while AQP0 labelling was abruptly lost in the lens nucleus due to C-terminal truncation. Our results show that the spatial distribution patterns of AQP0 and AQP5 observed in the adult lens are established during a narrow window of post natal development (P6-P15) that precedes eye opening and coincides

  19. Xenopus laevis Oocytes as a Model System for Studying the Interaction Between Asbestos Fibres and Cell Membranes.

    Science.gov (United States)

    Bernareggi, Annalisa; Ren, Elisa; Borelli, Violetta; Vita, Francesca; Constanti, Andrew; Zabucchi, Giuliano

    2015-06-01

    The mode of interaction of asbestos fibres with cell membranes is still debatable. One reason is the lack of a suitable and convenient cellular model to investigate the causes of asbestos toxicity. We studied the interaction of asbestos fibres with Xenopus laevis oocytes, using electrophysiological and morphological methods. Oocytes are large single cells, with a limited ability to endocytose molecular ligands; we therefore considered these cells to be a good model for investigating the nature of asbestos/membrane interactions. Electrophysiological recordings were performed to compare the passive electrical membrane properties, and those induced by applying positive or negative voltage steps, in untreated oocytes and those exposed to asbestos fibre suspensions. Ultrastructural analysis visualized in detail, any morphological changes of the surface membrane caused by the fibre treatment. Our results demonstrate that Amosite and Crocidolite-type asbestos fibres significantly modify the properties of the membrane, starting soon after exposure. Cells were routinely depolarized, their input resistance decreased, and the slow outward currents evoked by step depolarizations were dramatically enhanced. Reducing the availability of surface iron contained in the structure of the fibres with cation chelators, abolished these effects. Ultrastructural analysis of the fibre-exposed oocytes showed no evidence of phagocytic events. Our results demonstrate that asbestos fibres modify the oocyte membrane, and we propose that these cells represent a viable model for studying the asbestos/cell membrane interaction. Our findings also open the possibly for finding specific competitors capable of hindering the asbestos-cell membrane interaction as a means of tackling the long-standing asbestos toxicity problem. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Lens epithelial cell apoptosis and intracellular Ca2+ increase in the presence of xanthurenic acid

    Directory of Open Access Journals (Sweden)

    Richter Christoph

    2002-04-01

    Full Text Available Abstract Background Xanthurenic acid is an endogenous product of tryptophan degradation by indoleamine 2,3-dioxygenase (IDO. We have previously reported that IDO is present in mammalian lenses, and xanthurenic acid is accumulated in the lenses with aging. Here, we studied the involvement of xanthurenic acid in the human lens epithelial cell physiology. Methods Human lens epithelial cells primary cultures were used. Control cells, and cells in the presence of xanthurenic acid grow in the dark. Western blot analysis and immunofluorescence studies were performed. Results In the presence of xanthurenic acid human lens epithelial cells undergo apoptosis-like cell death. In the control cells gelsolin stained the perinuclear region, whereas in the presence of 10 μM xanthurenic acid gelsolin is translocated to the cytoskeleton, but does not lead to cytoskeleton breakdown. In the same condition caspase-3 activation, and DNA fragmentation was observed. At low (5 to 10 μM of xanthurenic acid concentration, the elongation of the cytoskeleton was associated with migration of mitochondria and cytochrome c release. At higher concentrations xanthurenic acid (20 μM and 40 μM damaged mitochondria were observed in the perinuclear region, and nuclear DNA cleavage was observed. We observed an induction of calpain Lp 82 and an increase of free Ca2+ in the cells in a xanthurenic acid concentration-dependent manner. Conclusions The results show that xanthurenic acid accumulation in human lens epithelial cells disturbs the normal cell physiology and leads to a cascade of pathological events. Xanthurenic acid induces calpain Lp82 and caspases in the cells growing in the dark and can be involved in senile cataract development.

  1. The role of mast cells and fibre type in ischaemia reperfusion injury of murine skeletal muscles

    Directory of Open Access Journals (Sweden)

    Bortolotto Susan K

    2004-09-01

    Full Text Available Abstract Background Ischaemia reperfusion (IR injury of skeletal muscle, is a significant cause of morbidity following trauma and surgical procedures, in which muscle fibre types exhibit different susceptibilities. The relative degree of mast cell mediated injury, within different muscle types, is not known. Methods In this study we compared susceptibility of the fast-twitch, extensor digitorum longus (EDL, mixed fast/slow-twitch gastrocnemius and the predominately slow-twitch soleus, muscles to ischemia reperfusion (IR injury in four groups of mice that harbour different mast cell densities; C57/DBA mast cell depleted (Wf/Wf, their heterozygous (Wf/+ and normal littermates (+/+ and control C57BL/6 mice. We determined whether susceptibility to IR injury is associated with mast cell content and/or fibre type and/or mouse strain. In experimental groups, the hind limbs of mice were subjected to 70 minutes warm tourniquet ischemia, followed by 24 h reperfusion, and the muscle viability was assessed on fresh whole-mount slices by the nitroblue tetrazolium (NBT histochemical assay. Results Viability was remarkably higher in the Wf/Wf strain irrespective of muscle type. With respect to muscle type, the predominately slow-twitch soleus muscle was significantly more resistant to IR injury than gastrocnemius and the EDL muscles in all groups. Mast cell density was inversely correlated to muscle viability in all types of muscle. Conclusion These results show that in skeletal muscle, IR injury is dependent upon both the presence of mast cells and on fibre type and suggest that a combination of preventative therapies may need to be implemented to optimally protect muscles from IR injury.

  2. Regulation of gene expression by Pax6 in ocular cells: a case of tissue-preferred expression of crystallins in lens

    OpenAIRE

    CVEKL, ALES; YANG, YING; CHAUHAN, BHARESH K.; CVEKLOVA, KVETA

    2004-01-01

    Lens development is an excellent model for genetic and biochemical studies of embryonic induction, cell cycle regulation, cellular differentiation and signal transduction. Differentiation of lens is characterized by lens-preferred expression and accumulation of water-soluble proteins, crystallins. Crystallins are required for light transparency, refraction and maintenance of lens integrity. Here, we review mechanisms of lens-preferred expression of crystallin genes by employing synergism betw...

  3. Cx43, ZO-1, alpha-catenin and beta-catenin in cataractous lens ...

    Indian Academy of Sciences (India)

    2012-10-17

    Oct 17, 2012 ... The strengthening of intercellular cadherin bonds in a mechanism independent of the actin cytoskeleton is facilitated by recruitment of alpha-catenin to cadherin com- plexes (Bajpai et al. 2008). Catenins are expressed through- out the lens. During early stages of fibre cell differentiation, the Wnt/β-catenin ...

  4. Myostatin inhibition induces muscle fibre hypertrophy prior to satellite cell activation

    Science.gov (United States)

    Wang, Qian; McPherron, Alexandra C

    2012-01-01

    Muscle fibres are multinucleated post-mitotic cells that can change dramatically in size during adulthood. It has been debated whether muscle fibre hypertrophy requires activation and fusion of muscle stem cells, the satellite cells. Myostatin (MSTN) is a negative regulator of skeletal muscle growth during development and in the adult, and MSTN inhibition is therefore a potential therapy for muscle wasting diseases, some of which are associated with a depletion of satellite cells. Conflicting results have been obtained in previous analyses of the role of MSTN on satellite cell quiescence. Here, we inhibited MSTN in adult mice with a soluble activin receptor type IIB and analysed the incorporation of new nuclei using 5′-bromo-2′-deoxyuridine (BrdU) labelling by isolating individual myofibres. We found that satellite cells are activated by MSTN inhibition. By varying the dose and time course for MSTN inhibition, however, we found that myofibre hypertrophy precedes the incorporation of new nuclei, and that the overall number of new nuclei is relatively low compared to the number of total myonuclei. These results reconcile some of the previous work obtained by other methods. In contrast with previous reports, we also found that Mstn null mice do not have increased satellite cell numbers during adulthood and are not resistant to sarcopaenia. Our results support a previously proposed model of hypertrophy in which hypertrophy can precede satellite cell activation. Studies of the metabolic and functional effects of postnatal MSTN inhibition are needed to determine the consequences of increasing the cytoplasm/myonuclear ratio after MSTN inhibition. PMID:22393251

  5. Ferulic Acid Suppresses Amyloid β Production in the Human Lens Epithelial Cell Stimulated with Hydrogen Peroxide

    Science.gov (United States)

    Nagai, Noriaki; Kotani, Sachiyo; Mano, Yu; Ueno, Akina; Ito, Yoshimasa; Kitaba, Toshio; Takata, Takumi

    2017-01-01

    It is well known that oxidative stresses induce the production of amyloid β (Aβ) in the brain, lens, and retina, leading to age-related diseases. In the present study, we investigated the effects of ferulic acid on the Aβ levels in H2O2-stimulated human lens epithelial (HLE) SRA 01/04 cells. Three types of Aβ peptides (Aβ1-40, Aβ1-42, and Aβ1-43) were measured by ELISA, and the levels of mRNA for the expressed proteins related to Aβ production (APP, BACE1, and PS proteins) and degradation (ADAM10, NEP, and ECE1 proteins) were determined by quantitative real-time RT-PCR. H2O2 stimulation augmented gene expression of the proteins related to Aβ production, resulting in the production of three types of Aβ peptides. Treatment with 0.1 μM ferulic acid attenuated the augmentations of gene expression and production of the proteins related to the secretion of three types of Aβ peptides in the H2O2-stimulated HLE cells. These results provided evidence of antioxidative functions of ferulic acid for lens epithelial cells. PMID:28409157

  6. Andrographolide reduces proliferation and migration of lens epithelial cells by modulating PI3K/Akt pathway.

    Science.gov (United States)

    Kayastha, Forum; Madhu, Hardik; Vasavada, Abhay; Johar, Kaid

    2014-11-01

    Lens epithelial cell proliferation, migration, and transdifferentiation are involved in the development of subcapsular cataracts and postoperative capsular opacification (PCO). PI3K/Akt pathway is involved in the proliferation and migration of lens epithelial cells. Andrographolide is the main bioactive component of Andrographis paniculata and is known to possess anti-proliferative and anti-migratory activities. The purpose of this study is to evaluate the effect of andrographolide on proliferation and migration induced by growth factors (TGF-β and bFGF) in the lens epithelial cell line, FHL 124. We have also evaluated the role of the PI3K/Akt pathway and its alteration by andrographolide during proliferation and migration of lens epithelial cells. The results showed that andrographolide significantly inhibited proliferation in a dose and time dependent manner. The growth factors, TGF-β and bFGF, induced migration of lens epithelial cells, which was lowered by andrographolide. The growth factors also up regulated phosphorylated Akt (Ser473) and Akt (Thr308), which was abolished by simultaneous treatment of andrographolide. Similar changes were also observed with the PI3K inhibitor, LY290042. Our findings suggest that andrographolide reduces proliferation, migration, and phosphorylated Akt levels in lens epithelial cells. Hence andrographolide can be utilized for the prevention of PCO. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Curcuma longa extract as a histological dye for collagen fibres and red blood cells

    Science.gov (United States)

    Avwioro, O G; Onwuka, S K; Moody, J O; Agbedahunsi, J M; Oduola, T; Ekpo, O E; Oladele, A A

    2007-01-01

    Crude ethanolic extract and column chromatographic fractions of the Allepey cultivar of Curcuma longa Roxb, commonly called turmeric (tumeric) in commerce, were used as a stain for tissue sections. Staining was carried out under basic, acidic and neutral media conditions. Inorganic and organic dissolution solvents were used. The stain was used as a counterstain after alum and iron haematoxylins. C. longa stained collagen fibres, cytoplasm, red blood cells and muscle cells yellow. It also stained in a fashion similar to eosin, except for its intense yellow colour. Preliminary phytochemical evaluation of the active column fraction revealed that it contained flavonoids, free anthraquinone and deoxy sugar. A cheap, natural dye can thus be obtained from C. longa. PMID:17451535

  8. Lipid-protein interactions in plasma membranes of fiber cells isolated from the human eye lens.

    Science.gov (United States)

    Raguz, Marija; Mainali, Laxman; O'Brien, William J; Subczynski, Witold K

    2014-03-01

    The protein content in human lens membranes is extremely high, increases with age, and is higher in the nucleus as compared with the cortex, which should strongly affect the organization and properties of the lipid bilayer portion of intact membranes. To assess these effects, the intact cortical and nuclear fiber cell plasma membranes isolated from human lenses from 41- to 60-year-old donors were studied using electron paramagnetic resonance spin-labeling methods. Results were compared with those obtained for lens lipid membranes prepared from total lipid extracts from human eyes of the same age group [Mainali, L., Raguz, M., O'Brien, W. J., and Subczynski, W. K. (2013) Biochim. Biophys. Acta]. Differences were considered to be mainly due to the effect of membrane proteins. The lipid-bilayer portions of intact membranes were significantly less fluid than lipid bilayers of lens lipid membranes, prepared without proteins. The intact membranes were found to contain three distinct lipid environments termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain. However, the cholesterol bilayer domain, which was detected in cortical and nuclear lens lipid membranes, was not detected in intact membranes. The relative amounts of bulk and trapped lipids were evaluated. The amount of lipids in domains uniquely formed due to the presence of membrane proteins was greater in nuclear membranes than in cortical membranes. Thus, it is evident that the rigidity of nuclear membranes is greater than that of cortical membranes. Also the permeability coefficients for oxygen measured in domains of nuclear membranes were significantly lower than appropriate coefficients measured in cortical membranes. Relationships between the organization of lipids into lipid domains in fiber cells plasma membranes and the organization of membrane proteins are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Andrographolide suppresses epithelial mesenchymal transition by inhibition of MAPK signalling pathway in lens epithelial cells.

    Science.gov (United States)

    Kayastha, Forum; Johar, Kaid; Gajjar, Devarshi; Arora, Anshul; Madhu, Hardik; Ganatra, Darshini; Vasavada, Abhay

    2015-06-01

    Epithelial mesenchymal transition (EMT) of lens epithelial cells (LECs) may contribute to the development of posterior capsular opacification (PCO), which leads to visual impairment. Andrographolide has been shown to have therapeutic potential against various cancers. However, its effect on human LECs is still unknown. The purpose of this study is to evaluate the effect of andrographolide on EMT induced by growth factors in the fetal human lens epithelial cell line (FHL 124). Initially the LECs were treated with growth factors (TGF-beta 2 and bFGF) to induce EMT. Subsequently these EMT-induced cells were treated with andrographolide at 100 and 500 nM concentrations for 24 h. Our results showed that FHL 124 cells treated with growth factors had a significant decrease in protein and m-RNA levels of epithelial markers pax6 and E-Cadherin. After administering andrographolide, these levels significantly increased. It was noticed that EMT markers alpha-SMA, fibronectin and collagen IV significantly decreased after treatment with andrographolide when compared to the other group. Treatment with andrographolide significantly inhibited phosphorylation of ERK and JNK. Cell cycle analysis showed that andrographolide did not arrest cells at G0/G1 or G2/M at tested concentrations. Our findings suggest that andrographolide helps sustain epithelial characteristics by modulating EMT markers and inhibiting the mitogen-activated protein kinase (MAPK) signalling pathway in LECs. Hence it can prove to be useful in curbing EMT-mediated PCO.

  10. Dislocations in single hemp fibres-investigations into the relationship of structural distortions and tensile properties at the cell wall level

    DEFF Research Database (Denmark)

    Thygesen, Lisbeth Garbrecht; Eder, M.; Burgert, I.

    2007-01-01

    The relationship between dislocations and mechanical properties of single hemp fibres (Cannabis sativa L. var. Felina) was studied using a microtensile testing setup in a 2-fold approach. In a first investigation the percentage of dislocations was quantified using polarized light microscopy (PLM......) prior to microtensile testing of the fibres. In a second approach PLM was used to monitor the dislocations while straining single fibres. The first part of the study comprised 53 hemp fibres with up to 20% of their cell wall consisting of dislocations. For this data set the percentage of dislocations...

  11. Presbyopia and heat: changes associated with aging of the human lens suggest a functional role for the small heat shock protein, alpha-crystallin, in maintaining lens flexibility.

    Science.gov (United States)

    Heys, Karl R; Friedrich, Michael G; Truscott, Roger J W

    2007-12-01

    Presbyopia, the inability to focus up close, affects everyone by age 50 and is the most common eye condition. It is thought to result from changes to the lens over time making it less flexible. We present evidence that presbyopia may be the result of age-related changes to the proteins of the lens fibre cells. Specifically, we show that there is a progressive decrease in the concentration of the chaperone, alpha-crystallin, in human lens nuclei with age, as it becomes incorporated into high molecular weight aggregates and insoluble protein. This is accompanied by a large increase in lens stiffness. Stiffness increases even more dramatically after middle age following the disappearance of free soluble alpha-crystallin from the centre of the lens. These alterations in alpha-crystallin and aggregated protein in human lenses can be reproduced simply by exposing intact pig lenses to elevated temperatures, for example, 50 degrees C. In this model system, the same protein changes are also associated with a progressive increase in lens stiffness. These data suggest a functional role for alpha-crystallin in the human lens acting as a small heat shock protein and helping to maintain lens flexibility. Presbyopia may be the result of a loss of alpha-crystallin coupled with progressive heat-induced denaturation of structural proteins in the lens during the first five decades of life.

  12. Potential pre-cataractous markers induced by low-dose radiation effects in cultured human lens cells

    Science.gov (United States)

    Blakely, E.; McNamara, M.; Bjornstad, K.; Chang, P.

    The human lens is one of the most radiosensitive organs of the body. Cataract, the opacification of the lens, is a late-appearing response to radiation damage. Recent evidence indicates that exposure to relatively low doses of space radiation are associated with an increased incidence and early appearance of human cataracts (Cucinotta et al., Radiat. Res. 156:460-466, 2001). Basic research in this area is needed to integrate the early responses of various late-responding tissues into our understanding and estimation of radiation risk for space travel. In addition, these studies may contribute to the development of countermeasures for the early lenticular changes, in order to prevent the late sequelae. Radiation damage to the lens is not life threatening but, if severe, can affect vision unless surgically corrected with synthetic lens replacement. The lens, however, may be a sensitive detector of radiation effects for other cells of ectodermal origin in the body for which there are not currently clear endpoints of low-dose radiation effects. We have investigated the dose-dependent expression of several radiation-responsive endpoints using our in vitro model of differentiating human lens epithelial cells (Blakely et al., Investigative Ophthalmology &Visual Sciences, 41(12):3898-3907, 2000). We have investigated radiation effects on several gene families that include, or relate to, DNA damage, cytokines, cell-cycle regulators, cell adhesion molecules, cell cytoskeletal function and apoptotic cell death. In this paper we will summarize some of our dose-dependent data from several radiation types, and describe the model of molecular and cellular events that we believe may be associated with precataractous events in the human lens after radiation exposure. This work was supported by NASA Grant #T-965W.

  13. 3D non-woven polyvinylidene fluoride scaffolds: fibre cross section and texturizing patterns have impact on growth of mesenchymal stromal cells.

    Science.gov (United States)

    Schellenberg, Anne; Ross, Robin; Abagnale, Giulio; Joussen, Sylvia; Schuster, Philipp; Arshi, Annahit; Pallua, Norbert; Jockenhoevel, Stefan; Gries, Thomas; Wagner, Wolfgang

    2014-01-01

    Several applications in tissue engineering require transplantation of cells embedded in appropriate biomaterial scaffolds. Such structures may consist of 3D non-woven fibrous materials whereas little is known about the impact of mesh size, pore architecture and fibre morphology on cellular behavior. In this study, we have developed polyvinylidene fluoride (PVDF) non-woven scaffolds with round, trilobal, or snowflake fibre cross section and different fibre crimp patterns (10, 16, or 28 needles per inch). Human mesenchymal stromal cells (MSCs) from adipose tissue were seeded in parallel on these scaffolds and their growth was compared. Initial cell adhesion during the seeding procedure was higher on non-wovens with round fibres than on those with snowflake or trilobal cross sections. All PVDF non-woven fabrics facilitated cell growth over a time course of 15 days. Interestingly, proliferation was significantly higher on non-wovens with round or trilobal fibres as compared to those with snowflake profile. Furthermore, proliferation increased in a wider, less dense network. Scanning electron microscopy (SEM) revealed that the MSCs aligned along the fibres and formed cellular layers spanning over the pores. 3D PVDF non-woven scaffolds support growth of MSCs, however fibre morphology and mesh size are relevant: proliferation is enhanced by round fibre cross sections and in rather wide-meshed scaffolds.

  14. 3D non-woven polyvinylidene fluoride scaffolds: fibre cross section and texturizing patterns have impact on growth of mesenchymal stromal cells.

    Directory of Open Access Journals (Sweden)

    Anne Schellenberg

    Full Text Available Several applications in tissue engineering require transplantation of cells embedded in appropriate biomaterial scaffolds. Such structures may consist of 3D non-woven fibrous materials whereas little is known about the impact of mesh size, pore architecture and fibre morphology on cellular behavior. In this study, we have developed polyvinylidene fluoride (PVDF non-woven scaffolds with round, trilobal, or snowflake fibre cross section and different fibre crimp patterns (10, 16, or 28 needles per inch. Human mesenchymal stromal cells (MSCs from adipose tissue were seeded in parallel on these scaffolds and their growth was compared. Initial cell adhesion during the seeding procedure was higher on non-wovens with round fibres than on those with snowflake or trilobal cross sections. All PVDF non-woven fabrics facilitated cell growth over a time course of 15 days. Interestingly, proliferation was significantly higher on non-wovens with round or trilobal fibres as compared to those with snowflake profile. Furthermore, proliferation increased in a wider, less dense network. Scanning electron microscopy (SEM revealed that the MSCs aligned along the fibres and formed cellular layers spanning over the pores. 3D PVDF non-woven scaffolds support growth of MSCs, however fibre morphology and mesh size are relevant: proliferation is enhanced by round fibre cross sections and in rather wide-meshed scaffolds.

  15. Microplasma Induced Cell Morphological Changes and Apoptosis of Ex Vivo Cultured Human Anterior Lens Epithelial Cells - Relevance to Capsular Opacification.

    Directory of Open Access Journals (Sweden)

    Nina Recek

    Full Text Available Inducing selective or targeted cell apoptosis without affecting large number of neighbouring cells remains a challenge. A plausible method for treatment of posterior capsular opacification (PCO due to remaining lens epithelial cells (LECs by reactive chemistry induced by localized single electrode microplasma discharge at top of a needle-like glass electrode with spot size ~3 μm is hereby presented. The focused and highly-localized atmospheric pressure microplasma jet with electrode discharge could induce a dose-dependent apoptosis in selected and targeted individual LECs, which could be confirmed by real-time monitoring of the morphological and structural changes at cellular level. Direct cell treatment with microplasma inside the medium appeared more effective in inducing apoptosis (caspase 8 positivity and DNA fragmentation at a highly targeted cell level compared to treatment on top of the medium (indirect treatment. Our results show that single cell specific micropipette plasma can be used to selectively induce demise in LECs which remain in the capsular bag after cataract surgery and thus prevent their migration (CXCR4 positivity to the posterior lens capsule and PCO formation.

  16. Primary culture and growth characteristics of four different species of lens epithelial cells

    Directory of Open Access Journals (Sweden)

    Li-Xia Ji

    2015-07-01

    Full Text Available AIM: To explore the primary culture conditions for four kinds of lens epithelial cells(LECsof rat, rabbit, dog, and human, and measure their growth characteristics. METHODS: The lens capsule or anterior capsular tissue of rat, rabbit, dog and patient were removed by different methods, and they were cut into tiny pieces for primary culture by modified tissue adherent method. The morphological features of four kinds of LECs were observed under an inverted microscope.RESULTS: Four kinds of LECs of rat, rabbit, dog and human could be cultured primarily by tissue adherent method. With the evolution of tissue source, the adherent capacity of LECs gradually strengthened, cells form were changed from irregular polygon to oval, nucleus rounded and cytoplasm enriched gradually. Four kinds of LECs had fibrotic changes after several passages.CONCLUSION: LECs of rat, rabbit, dog and human can be primarily cultured. This method lays the foundation for the mechanism research of caratact and related fields on the cellular and molecular levels.

  17. 51Cr release and oxidative stress in the lens

    International Nuclear Information System (INIS)

    Stewart-DeHaan, P.J.; Sanwal, M.; Creighton, M.O.; Inch, W.R.; Trevithick, J.R.

    1989-01-01

    Examination of the opaque areas of human cortical cataracts has shown that a large portion of the opacity could be attributed to the globules found there. We tested models involving globule formation as a result of oxidative damage to rat lens cells in culture and whole chick embryo lenses. When cell monolayers from a lens cell line were exposed to oxidizing conditions they developed globules on the cell surface. The cells were protected from damage by the addition of glutathione and vitamin C. Thirteen-day chick embryo lenses were also incubated in oxidizing conditions and the amount of cellular damage was assessed using a chromium-51 release assay we have developed. After 24 hr the percent 51Cr in the medium increased by an average of 20% as a result of 10 mM hydrogen peroxide treatment. The addition of the 10 mM vitamin C to the hydrogen peroxide significantly reduced the 51Cr leakage to the control level. Light microscopy of sections of the lens showed a breakdown of the equatorial fibre arrangement in the presence of H2O2, while addition of vitamin C restored the fibre organization to almost normal. The findings suggest that oxidative stress is an important step in cataractogenesis and point towards the use of water soluble antioxidants as protective agents

  18. High-temperature tensile cell for in situ real-time investigation of carbon fibre carbonization and graphitization processes

    Energy Technology Data Exchange (ETDEWEB)

    Behr, Michael; Rix, James; Landes, Brian; Barton, Bryan; Billovits, Gerry; Hukkanen, Eric; Patton, Jasson; Wang, Weijun; Keane, Denis; Weigand, Steven (Dow); (NWU)

    2016-10-17

    A new high-temperature fibre tensile cell is described, developed for use at the Advanced Photon Source at Argonne National Laboratory to enable the investigation of the carbonization and graphitization processes during carbon fibre production. This cell is used to heat precursor fibre bundles to temperatures up to ~2300°C in a controlled inert atmosphere, while applying tensile stress to facilitate formation of highly oriented graphitic microstructure; evolution of the microstructure as a function of temperature and time during the carbonization and higher-temperature graphitization processes can then be monitored by collecting real-time wide-angle X-ray diffraction (WAXD) patterns. As an example, the carbonization and graphitization behaviour of an oxidized polyacrylonitrile fibre was studied up to a temperature of ~1750°C. Real-time WAXD revealed the gradual increase in microstructure alignment with the fibre axis with increasing temperature over the temperature range 600–1100°C. Above 1100°C, no further changes in orientation were observed. The overall magnitude of change increased with increasing applied tensile stress during carbonization. As a second example, the high-temperature graphitizability of PAN- and pitch-derived commercial carbon fibres was studied. Here, the magnitude of graphitic microstructure evolution of the pitch-derived fibre far exceeded that of the PAN-derived fibres at temperatures up to ~2300°C, indicating its facile graphitizability.

  19. Properties of Fiber Cell Plasma Membranes Isolated from the Cortex and Nucleus of the Porcine Eye Lens

    Science.gov (United States)

    Mainali, Laxman; Raguz, Marija; O’Brien, William J.; Subczynski, Witold K.

    2012-01-01

    The organization and physical properties of the lipid bilayer portion of intact cortical and nuclear fiber cell plasma membranes isolated from the eyes lenses of two-year-old pigs were studied using electron paramagnetic resonance (EPR) spin-labeling. Membrane fluidity, hydrophobicity, and the oxygen transport parameter (OTP) were assessed from the EPR spectra of precisely positioned spin labels. Intact cortical and nuclear membranes, which include membrane proteins, were found to contain three distinct lipid environments. These lipid environments were termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain (lipids in protein aggregates). The amount of boundary and trapped lipids was greater in intact nuclear membranes than in cortical membranes. The properties of intact membranes were compared with the organization and properties of lens lipid membranes made of the total lipid extracts from the lens cortex or nucleus. In cortical lens lipid membranes, only one homogenous environment was detected, which was designated as a bulk lipid domain (phospholipid bilayer saturated with cholesterol). Lens lipid membranes prepared from the lens nucleus possessed two domains, assigned as a bulk lipid domain and a cholesterol bilayer domain (CBD). In intact nuclear membranes, it was difficult to discriminate the CBD, which was clearly detected in nuclear lens lipid membranes because the OTP measured in the CBD is the same as in the domain formed by trapped lipids. The two domains unique to intact membranes—namely, the domain formed by boundary lipids and the domain formed by trapped lipids—were most likely formed due to the presence of membrane proteins. It is concluded that formation of rigid and practically impermeable domains is enhanced in the lens nucleus, indicating changes in membrane composition that may help to maintain low oxygen concentration in this lens region. PMID:22326289

  20. AGE-RAGE interaction in the TGFβ2-mediated epithelial to mesenchymal transition of human lens epithelial cells.

    Science.gov (United States)

    Raghavan, Cibin T; Nagaraj, Ram H

    2016-08-01

    Basement membrane (BM) proteins accumulate chemical modifications with age. One such modification is glycation, which results in the formation of advanced glycation endproducts (AGEs). In a previous study, we reported that AGEs in the human lens capsule (BM) promote the TGFβ2-mediated epithelial-to-mesenchymal transition (EMT) of lens epithelial cells, which we proposed as a mechanism for posterior capsule opacification (PCO) or secondary cataract formation. In this study, we investigated the role of a receptor for AGEs (RAGE) in the TGFβ2-mediated EMT in a human lens epithelial cell line (FHL124). RAGE was present in FHL124 cells, and its levels were unaltered in cells cultured on either native or AGE-modified BM or upon treatment with TGFβ2. RAGE overexpression significantly enhanced the TGFβ2-mediated EMT responses in cells cultured on AGE-modified BM compared with the unmodified matrix. In contrast, treatment of cells with a RAGE antibody or EN-RAGE (an endogenous ligand for RAGE) resulted in a significant reduction in the TGFβ2-mediated EMT response. This was accompanied by a reduction in TGFβ2-mediated Smad signaling and ROS generation. These results imply that the interaction of matrix AGEs with RAGE plays a role in the TGFβ2-mediated EMT of lens epithelial cells and suggest that the blockade of RAGE could be a strategy to prevent PCO and other age-associated fibrosis.

  1. Conjunctival Goblet Cell Function: Effect of Contact Lens Wear and Cytokines.

    Science.gov (United States)

    García-Posadas, Laura; Contreras-Ruiz, Laura; Soriano-Romaní, Laura; Dartt, Darlene A; Diebold, Yolanda

    2016-03-01

    This review focuses on conjunctival goblet cells and their essential function in the maintenance of eye health. The main function of goblet cells is to produce and secrete mucins that lubricate the ocular surface. An excess or a defect in those mucins leads to several alterations that makes goblet cells central players in maintaining the proper mucin balance and ensuring the correct function of ocular surface tissues. A typical pathology that occurs with mucous deficiency is dry eye disease, whereas the classical example of mucous hyperproduction is allergic conjunctivitis. In this review, we analyze how goblet cell number and function can be altered in these diseases and in contact lens (CL) wearers. We found that most published studies focused exclusively on the goblet cell number. However, recent advances have demonstrated that, along with mucin secretion, goblet cells are also able to secrete cytokines and respond to them. We describe the effect of different cytokines on goblet cell proliferation and secretion. We conclude that it is important to further explore the effect of CL wear and cytokines on conjunctival goblet cell function.

  2. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    International Nuclear Information System (INIS)

    Nogueira, P; Vaz, P; Zankl, M; Schlattl, H

    2011-01-01

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  3. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, P; Vaz, P [Technological and Nuclear Institute, Estrada Nacional No 10, 2686-953 Sacavem (Portugal); Zankl, M; Schlattl, H, E-mail: pedro.nogueira@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen-German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  4. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations.

    Science.gov (United States)

    Nogueira, P; Zankl, M; Schlattl, H; Vaz, P

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  5. Long-term corneal endothelial cell changes in pediatric intraocular lens reposition and exchange cases.

    Science.gov (United States)

    Wang, Yan; Wu, Mingxing; Zhu, Liyuan; Liu, Yizhi

    2012-04-01

    To evaluate long-term corneal endothelial cell changes of intraocular lens (IOL) reposition and exchange in children. State key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China In this retrospective study, all IOL reposition and exchange procedures performed in patients under 14 years old between January 1999 and April 2009 were included. Follow-up outcomes included corneal endothelial cell density, hexagonality, coefficient of variance, average cell size. IOL reposition procedures in 12 eyes (12 cases) (reposition group, RPG), and IOL exchanges in eight eyes (eight cases) (exchange group, EXG) were performed because of IOL pupillary capture or IOL dislocation. Median of follow-up was 44.5 months in RPG and 66.2 months in EXG. The density of corneal endothelial cells in RPG (2,053 ± 493/mm(2)) and EXG (2,100 ± 758/mm(2)) was significantly decreased in comparison to the control eyes (3,116 ± 335/mm(2)). Hexagonality of corneal endothelial cells and coefficient of variance showed no difference among the control group, RPG and EXG (P > 0.05). The density of corneal endothelial cells was conspicuously decreased after IOL reposition or exchange procedures in childhood cases. Longer follow-up must be conducted in these cases.

  6. Effect of superposed electromagnetic noise on DNA damage of lens epithelial cells induced by microwave radiation.

    Science.gov (United States)

    Yao, Ke; Wu, Wei; Yu, Yibo; Zeng, Qunli; He, Jiliang; Lu, Deqiang; Wang, Kaijun

    2008-05-01

    To investigate the influence of the 1.8-GHz radiofrequency fields (RFs) of the Global System for Mobile Communications on DNA damage, intracellular reactive oxygen species (ROS) formation, cell cycle, and apoptosis in human lens epithelial cells (hLECs) and whether the effects induced by RF could be blocked by superposing of electromagnetic noise. After 24-hour intermittent exposure at the specific absorption rate of 1 W/kg, 2 W/kg, 3 W/kg, and 4 W/kg, the DNA damage of hLECs was examined by alkaline comet assay and immunofluorescence microscope detection of the phosphorylated form of histone variant H2AX (gammaH2AX) foci, respectively. ROS production was quantified by the fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Cell cycle and cell apoptosis were determined by flow cytometry. DNA damage examined by alkaline comet assay was significantly increased after 3 W/kg and 4 W/kg radiation (P radiation (P microwave radiation and sham exposure groups (P > 0.05). All the effects mentioned were blocked when the RF was superposed with 2 muT electromagnetic noise. Microwave radiation induced hLEC DNA damage after G(0)/G(1) arrest does not lead to cell apoptosis. The increased ROS observed may be associated with DNA damage. Superposed electromagnetic noise blocks microwave radiation-induced DNA damage, ROS formation, and cell cycle arrest.

  7. Gut Fermentation of Dietary Fibres: Physico-Chemistry of Plant Cell Walls and Implications for Health

    Directory of Open Access Journals (Sweden)

    Barbara A. Williams

    2017-10-01

    Full Text Available The majority of dietary fibre (DF originates from plant cell walls. Chemically, DF mostly comprise carbohydrate polymers, which resist hydrolysis by digestive enzymes in the mammalian small intestine, but can be fermented by large intestinal bacteria. One of the main benefits of DF relate to its fermentability, which affects microbial diversity and function within the gastro-intestinal tract (GIT, as well as the by-products of the fermentation process. Much work examining DF tends to focus on various purified ingredients, which have been extracted from plants. Increasingly, the validity of this is being questioned in terms of human nutrition, as there is evidence to suggest that it is the actual complexity of DF which affects the complexity of the GIT microbiota. Here, we review the literature comparing results of fermentation of purified DF substrates, with whole plant foods. There are strong indications that the more complex and varied the diet (and its ingredients, the more complex and varied the GIT microbiota is likely to be. Therefore, it is proposed that as the DF fermentability resulting from this complex microbial population has such profound effects on human health in relation to diet, it would be appropriate to include DF fermentability in its characterization—a functional approach of immediate relevance to nutrition.

  8. Regulation of gene expression by Pax6 in ocular cells: a case of tissue-preferred expression of crystallins in lens.

    Science.gov (United States)

    Cvekl, Ales; Yang, Ying; Chauhan, Bharesh K; Cveklova, Kveta

    2004-01-01

    Lens development is an excellent model for genetic and biochemical studies of embryonic induction, cell cycle regulation, cellular differentiation and signal transduction. Differentiation of lens is characterized by lens-preferred expression and accumulation of water-soluble proteins, crystallins. Crystallins are required for light transparency, refraction and maintenance of lens integrity. Here, we review mechanisms of lens-preferred expression of crystallin genes by employing synergism between developmentally regulated DNA-binding transcription factors: Pax6, c-Maf, MafA/L-Maf, MafB, NRL, Sox2, Sox1, RARbeta/RXRbeta, RORalpha, Prox1, Six3, gammaFBP-B and HSF2. These factors are differentially expressed in lens precursor cells, lens epithelium and primary and secondary lens fibers. They exert their function in combination with ubiquitously expressed factors (e.g. AP-1, CREB, pRb, TFIID and USF) and co-activators/chromatin remodeling proteins (e.g. ASC-2 and CBP/p300). A special function belongs to Pax6, a paired domain and homeodomain-containing protein, which is essential for lens formation. Pax6 is expressed in lens progenitor cells before the onset of crystallin expression and it serves as an important regulatory factor required for expression of c-Maf, MafA/L-Maf, Six3, Prox1 and retinoic acid signaling both in lens precursor cells and the developing lens. The roles of these factors are illustrated by promoter studies of mouse alphaA-, alphaB-, gammaF- and guinea pig zeta-crystallins. Pax6 forms functional complexes with a number of transcription factors including the retinoblastoma protein, pRb, MafA, Mitf and Sox2. We present novel data showing that pRb antagonizes Pax6-mediated activation of the alphaA-crystallin promoter likely by inhibiting binding of Pax6 to DNA.

  9. Fibre tracking

    International Nuclear Information System (INIS)

    Gaillard, J.M.

    1994-03-01

    A large-size scintillating plastic fibre tracking detector was built as part of the upgrade of the UA2 central detector at the SPS proton-antiproton collider. The cylindrical fibre detector of average radius of 40 cm consisted of 60000 plastic fibres with an active length of 2.1 m. One of the main motivations was to improve the electron identification. The fibre ends were bunched to be coupled to read-out systems of image intensifier plus CCD, 32 in total. The quality and the reliability of the UA2 fibre detector performance exceeded expectations throughout its years of operation. A few examples of the use of image intensifiers and of scintillating fibres in biological instrumentation are described. (R.P.) 11 refs., 15 figs., 2 tabs

  10. Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code

    CERN Document Server

    Stancari, Giulio; Redaelli, Stefano

    2014-01-01

    Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.

  11. Effects of LAR and PTP-BL phosphatase deficiency on adult mouse retinal cells activated by lens injury.

    NARCIS (Netherlands)

    Lorber, B.; Hendriks, W.J.A.J.; Zee, C.E.E.M. van der; Berry, M.; Logan, A.

    2005-01-01

    Using intact and lens-lesioned wildtype, leucocyte common antigen-related phosphatase deficient (LARDeltaP) and protein tyrosine phosphatase (PTP)-BAS-like phosphatase deficient (PTP-BLDeltaP) mice, we have evaluated the role of LAR and PTP-BL in retinal ganglion cell survival and neuritogenesis,

  12. High-efficiency thin and compact concentrator photovoltaics with micro-solar cells directly attached to a lens array.

    Science.gov (United States)

    Hayashi, Nobuhiko; Inoue, Daijiro; Matsumoto, Mitsuhiro; Matsushita, Akio; Higuchi, Hiroshi; Aya, Youichirou; Nakagawa, Tohru

    2015-06-01

    We propose a thin and compact concentrator photovoltaic (CPV) module, about 20 mm thick, one tenth thinner than those of conventional CPVs that are widely deployed for mega-solar systems, to broaden CPV application scenarios. We achieved an energy conversion efficiency of 37.1% at a module temperature of 25 °C under sunlight irradiation optimized for our module. Our CPV module has a lens array consisting of 10 mm-square unit lenses and micro solar cells that are directly attached to the lens array, to reduce the focal length of the concentrator and to reduce optical losses due to reflection. The optical loss of the lens in our module is about 9.0%, which is lower than that of conventional CPV modules with secondary optics. This low optical loss enables our CPV module to achieve a high energy conversion efficiency.

  13. Protective effect of lycopene for oxidative damage in human lens epithelial cells induced by UV

    Directory of Open Access Journals (Sweden)

    Jing-Wen Sun

    2016-05-01

    Full Text Available AIM:To investigate the protective effect and possible mechanisms of lycopene for oxidative damage induced by ultraviolet in cultured human lens epithelial cells(HLEC. METHODS:HLEC was subcultured and divided into negative control group, oxidative injury group, lycopene low dose group and lycopene high dose group. Cell viability was assayed by MTT colorimetric. Cell morphological changes were detected by electron microscope. Reactive oxygen species(ROSlevels were detected with DCFH-DA fluorescent probe. Content of superoxide dismutase(SOD, glutathione peroxidase(GSHand malondialdehyde(MDAin supernatants were detected by spectrophotometer. RESULTS:Lycopene could obviously inhibited UV-induced decline in cell activity, reduce UV-induced ROS generation within HLEC, cause SOD, GSH-Px levels increased and MDA levels decreased.CONCLUSION:Lycopene plays its strong antioxidant role in increasing the intracellular SOD and GSH-Px content levels and decreasing MDA levels, which provide reliable experimental basis for prevent and treatment of cataracts.

  14. Detection of macular ganglion cell loss in preperimetric glaucoma patients with localized retinal nerve fibre defects by spectral-domain optical coherence tomography.

    Science.gov (United States)

    Na, Jung Hwa; Lee, Kyoungsub; Lee, Jong Rak; Baek, Seunghee; Yoo, Sung Jun; Kook, Michael S

    2013-12-01

    To evaluate and compare the utility of ganglion cell complex with peripapillary retinal nerve fibre layer and optic nerve head measurements for detection of localized defects in patients with preperimetric glaucoma using spectral-domain optical coherence tomography. Prospective study. Preperimetric glaucoma patients. A total of 105 eyes with preperimetric glaucoma and 68 age- and refractive error-matched control eyes were enrolled. The ability to detect localized retinal nerve fibre layer defects by RTVue-100 spectral-domain optical coherence tomography (Optovue, Inc., Fremont, CA, USA) was assessed calculating the areas under receiver operating characteristic curves. The ability to detect localized retinal nerve fibre layer defects by spectral-domain optical coherence tomography. Global volume loss and superior ganglion cell complex thickness showed the largest area under receiver operating characteristic curve values (both areas under receiver operating characteristic curves 0.84, P fibre layer thickness afforded the best diagnostic capability (area under receiver operating characteristic curve 0.89, P optic nerve head parameters, the horizontal cup:disc ratio yielded the highest area under receiver operating characteristic curve (0.85, P fibre layer, and optic nerve head) (P > 0.02). Ganglion cell complex thickness was significantly reduced in eyes with preperimetric glaucoma. Ganglion cell complex imaging using spectral-domain optical coherence tomography may be a useful ancillary modality for detection of early macular changes in glaucomatous eyes with localized retinal nerve fibre layer defects. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  15. Effect of myopia on ganglion cell complex and peripapillary retinal nerve fibre layer measurements: a Fourier-domain optical coherence tomography study of young Chinese persons.

    Science.gov (United States)

    Zhao, Zhennan; Jiang, Chunhui

    2013-08-01

    To investigate the change of the ganglion cell complex and peripapillary retinal nerve fibre layer under different refractive conditions, as measured by optical coherence tomography. Cross-sectional observational study. A total of 107 eyes from 107 subjects were studied. Ganglion cell complex and retinal nerve fibre layer were studied by a spectral-domain system. Their relationship against spherical equivalents and axial length was studied. The thickness of ganglion cell complex and retinal nerve fibre layer at different area and under different refractive conditions as measurements by optical coherence tomography. The average, superior and inferior macular ganglion cell complex thickness was significantly associated with both spherical equivalents (all P fibre layer thicknesses from the superior, inferior and temporal quadrants were associated with both spherical equivalents (all P fibre layer thickness was studied in sections, then some parts of the upper and lower temporal part showed no correlation with either spherical equivalents or axial length (all P fibre layer were correlated with refraction and axial length. Therefore, when using these for clinical purposes, attention must be paid to the refractive state of the patient. © 2012 The Authors. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.

  16. Attenuation of oxygen fluctuation-induced endoplasmic reticulum stress in human lens epithelial cells.

    Science.gov (United States)

    Zheng, Xiao-Yu; Xu, Jia; Chen, X I; Li, Wei; Wang, Ting-Yan

    2015-11-01

    Cataractogenic stresses are associated with the induction of endoplasmic reticulum (ER) stress. However, little is known about oxygen (O 2 )-induced ER stress in the lens. Cataract research has focused on elevated levels of O 2 in lens epithelial cells (LECs). Excessive levels or a lack of O 2 are known to induce ER stress whereas chronic ER stress activates the unfolded protein response (UPR). The present study investigated the hypothesis that the fluctuation of O 2 levels induces a UPR, and may be controlled by maintaining human LECs (hLECs) in a specific concentration of O 2 . Human LECs were cultured in different atmospheric levels of O 2 . Hypoxic conditions were determined by the level of hypoxia-inducible factor (HIF)-1α. 2',7'-Dichlorodihydrofluorescein diacetate and ethidium homodimer-1 staining were conducted to detect reactive oxygen species (ROS) and cell death, respectively. Protein blot analyses were performed with antibodies specific to antioxidant and UPR-specific proteins. Reverse transcription-quantitatative polymerase chain reaction assays were performed to quantify the mRNA levels of activated NF-E2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 (Keap1). The treatment of human LECs with 0 and 20% atmospheric O 2 activated Nrf2/Keap1. The LECs shifted to 1% atmospheric O 2 from 0, 4 or 20% for 24 h showed decreased levels of Keap1. By contrast, hLECs cultured in 1% atmospheric O 2 for 24 h and then shifted to 0, 4 or 20% O 2 exhibited a significant upregulation of Nrf2. These results suggest that oxidative stress proteins were not expressed in a 1% O 2 environment. The O 2 levels in the culture medium were equilibrated within 2 h in the cell culture plates. These results showed that an appropriate oxygen environment for the culture of LECs is ~1 % atmospheric O 2 . Either 0 or 20% of atmospheric O 2 activated the UPR and the Nrf2/Keap1-mediated antioxidant system in LECs and chronic exposure to O 2 fluctuation led to ROS

  17. A role for smoothened during murine lens and cornea development.

    Directory of Open Access Journals (Sweden)

    Janet J Y Choi

    Full Text Available Various studies suggest that Hedgehog (Hh signalling plays roles in human and zebrafish ocular development. Recent studies (Kerr et al., Invest Ophthalmol Vis Sci. 2012; 53, 3316-30 showed that conditionally activating Hh signals promotes murine lens epithelial cell proliferation and disrupts fibre differentiation. In this study we examined the expression of the Hh pathway and the requirement for the Smoothened gene in murine lens development. Expression of Hh pathway components in developing lens was examined by RT-PCR, immunofluorescence and in situ hybridisation. The requirement of Smo in lens development was determined by conditional loss-of-function mutations, using LeCre and MLR10 Cre transgenic mice. The phenotype of mutant mice was examined by immunofluorescence for various markers of cell cycle, lens and cornea differentiation. Hh pathway components (Ptch1, Smo, Gli2, Gli3 were detected in lens epithelium from E12.5. Gli2 was particularly localised to mitotic nuclei and, at E13.5, Gli3 exhibited a shift from cytosol to nucleus, suggesting distinct roles for these transcription factors. Conditional deletion of Smo, from ∼E12.5 (MLR10 Cre did not affect ocular development, whereas deletion from ∼E9.5 (LeCre resulted in lens and corneal defects from E14.5. Mutant lenses were smaller and showed normal expression of p57Kip2, c-Maf, E-cadherin and Pax6, reduced expression of FoxE3 and Ptch1 and decreased nuclear Hes1. There was normal G1-S phase but decreased G2-M phase transition at E16.5 and epithelial cell death from E14.5-E16.5. Mutant corneas were thicker due to aberrant migration of Nrp2+ cells from the extraocular mesenchyme, resulting in delayed corneal endothelial but normal epithelial differentiation. These results indicate the Hh pathway is required during a discrete period (E9.5-E12.5 in lens development to regulate lens epithelial cell proliferation, survival and FoxE3 expression. Defective corneal development occurs

  18. A role for smoothened during murine lens and cornea development.

    Science.gov (United States)

    Choi, Janet J Y; Ting, Chao-Tung; Trogrlic, Lidia; Milevski, Stefan V; Familari, Mary; Martinez, Gemma; de Iongh, Robb U

    2014-01-01

    Various studies suggest that Hedgehog (Hh) signalling plays roles in human and zebrafish ocular development. Recent studies (Kerr et al., Invest Ophthalmol Vis Sci. 2012; 53, 3316-30) showed that conditionally activating Hh signals promotes murine lens epithelial cell proliferation and disrupts fibre differentiation. In this study we examined the expression of the Hh pathway and the requirement for the Smoothened gene in murine lens development. Expression of Hh pathway components in developing lens was examined by RT-PCR, immunofluorescence and in situ hybridisation. The requirement of Smo in lens development was determined by conditional loss-of-function mutations, using LeCre and MLR10 Cre transgenic mice. The phenotype of mutant mice was examined by immunofluorescence for various markers of cell cycle, lens and cornea differentiation. Hh pathway components (Ptch1, Smo, Gli2, Gli3) were detected in lens epithelium from E12.5. Gli2 was particularly localised to mitotic nuclei and, at E13.5, Gli3 exhibited a shift from cytosol to nucleus, suggesting distinct roles for these transcription factors. Conditional deletion of Smo, from ∼E12.5 (MLR10 Cre) did not affect ocular development, whereas deletion from ∼E9.5 (LeCre) resulted in lens and corneal defects from E14.5. Mutant lenses were smaller and showed normal expression of p57Kip2, c-Maf, E-cadherin and Pax6, reduced expression of FoxE3 and Ptch1 and decreased nuclear Hes1. There was normal G1-S phase but decreased G2-M phase transition at E16.5 and epithelial cell death from E14.5-E16.5. Mutant corneas were thicker due to aberrant migration of Nrp2+ cells from the extraocular mesenchyme, resulting in delayed corneal endothelial but normal epithelial differentiation. These results indicate the Hh pathway is required during a discrete period (E9.5-E12.5) in lens development to regulate lens epithelial cell proliferation, survival and FoxE3 expression. Defective corneal development occurs secondary to defects

  19. Optical fibres

    CERN Multimedia

    1992-01-01

    These optical fibres are used to detect particles passing through in bunches. Made from scintillating material, the fibres glow when a high energy particle passes through them. These detectors are known as spaghetti detectors and are used to measure the energy of particles.

  20. Feedback Regulation of Intracellular Hydrostatic Pressure in Surface Cells of the Lens.

    Science.gov (United States)

    Gao, Junyuan; Sun, Xiurong; White, Thomas W; Delamere, Nicholas A; Mathias, Richard T

    2015-11-03

    In wild-type lenses from various species, an intracellular hydrostatic pressure gradient goes from ∼340 mmHg in central fiber cells to 0 mmHg in surface cells. This gradient drives a center-to-surface flow of intracellular fluid. In lenses in which gap-junction coupling is increased, the central pressure is lower, whereas if gap-junction coupling is reduced, the central pressure is higher but surface pressure is always zero. Recently, we found that surface cell pressure was elevated in PTEN null lenses. This suggested disruption of a feedback control system that normally maintained zero surface cell pressure. Our purpose in this study was to investigate and characterize this feedback control system. We measured intracellular hydrostatic pressures in mouse lenses using a microelectrode/manometer-based system. We found that all feedback went through transport by the Na/K ATPase, which adjusted surface cell osmolarity such that pressure was maintained at zero. We traced the regulation of Na/K ATPase activity back to either TRPV4, which sensed positive pressure and stimulated activity, or TRPV1, which sensed negative pressure and inhibited activity. The inhibitory effect of TRPV1 on Na/K pumps was shown to signal through activation of the PI3K/AKT axis. The stimulatory effect of TRPV4 was shown in previous studies to go through a different signal transduction path. Thus, there is a local two-legged feedback control system for pressure in lens surface cells. The surface pressure provides a pedestal on which the pressure gradient sits, so surface pressure determines the absolute value of pressure at each radial location. We speculate that the absolute value of intracellular pressure may set the radial gradient in the refractive index, which is essential for visual acuity. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  1. Studies of P(L/D)LA 96/4 non-woven scaffolds and fibres; properties, wettability and cell spreading before and after intrusive treatment methods.

    Science.gov (United States)

    Ellä, Ville; Gomes, Manuela E; Reis, Rui L; Törmälä, Pertti; Kellomäki, Minna

    2007-06-01

    Poly(L/D)lactide 96/4 fibres with diameters of 50 and 80 microm were produced. The smaller diameter fibres were carded and needle punched to form a non-woven mat. Fibres and non-woven mats were hydrolysed for a period of 20 weeks. Fibres and pressed non-woven discs were treated with low-temperature oxygen plasma and alkaline KOH hydrolysis and ethanol washing was used as a reference treatment. The non-wovens lost 50% of their tear strength after 8 weeks in vitro while the fibres still retained 65% tensile strength after 20 weeks. Hydrolysation time in KOH, treatment time and power settings of the oxygen plasma were all directly proportional to the mechanical properties of the fibres. Increasing time (and power) resulted in lower tensile properties. Rapid wetting of the scaffolds was achieved by oxygen plasma, KOH hydrolysation and ethanol washing. Cell culturing using fibroblast cell line was carried out for the treated and non-treated non-woven scaffolds. In terms of adhesion and the spreading of the cells into the scaffold, best results after 3-day culturing were obtained for the oxygen plasma treated scaffolds.

  2. Lens Epithelial Cell Death Secondary to Acanthamoeba Keratitis: Absence of Capsular Bag Opacification Six Years after Cataract Surgery

    Directory of Open Access Journals (Sweden)

    Javier Moreno-Montañés

    2011-12-01

    Full Text Available Purpose: To show the evolution of anterior chamber structures 6 years after cataract surgery in a case with Acanthamoeba keratitis (AK. Methods: A 37-year-old woman with AK receiving long-term treatment with chlorhexidine, propamidine isethionate and steroids developed a white cataract and iris atrophy. Penetrating keratoplasty and cataract surgery were performed with subsequent intraocular pressure elevation requiring Molteno shunt implantation. Two years after the last surgery, endothelial decompensation developed and another penetrating keratoplasty was performed. Intraoperatively, the anterior and posterior capsules were completely transparent. Results: Six years after cataract surgery, the intraocular lens was centered with clear anterior and posterior capsules without lens epithelial cells proliferation. No Soemmering’s ring formation or posterior capsule opacification was found. Also, no zonular damage or pseudophacodonesis was observed. Conclusions: This case suggests that AK infection and AK treatment not only cause white progressive cataract but also lens epithelial cell death. The capsules may be completely clear 6 years after cataract surgery, with a good quality of vision regardless of intraocular lens material or design.

  3. Upper bound for energy efficiency in multi-cell fibre-wireless access systems

    DEFF Research Database (Denmark)

    Koonen, A.M.J.; Popov, M.; Wessing, Henrik

    2013-01-01

    Bringing radio access points closer to the end-users improves radio energy efficiency. However, taking into account both the radio and the optical parts of a fibre-wireless access system, the overall system energy efficiency has an upper bound determined by the relation between the energy...

  4. Benign Fibröz Histiositoma

    OpenAIRE

    ÖĞÜTCEN TOLLER, Melahat; ÖZKAN, Nilüfer; YILDIZ, Levent

    2015-01-01

    Benign fibröz histiositoma (BFH), ağız kavitesinde nadir görülen, klinik ve histopatolojik olarak teşhiste karışıklığa yol açan bir tümördür. Bu makalede, sağ mandibular bukkal bölgede görülen bir benign fibröz histiositoma vakası sunularak, klinik ve histopatolojik özellikleri tartışıldı.

  5. A study protocol to investigate the relationship between dietary fibre intake and fermentation, colon cell turnover, global protein acetylation and early carcinogenesis: the FACT study

    Directory of Open Access Journals (Sweden)

    Croucher Lisa J

    2009-09-01

    Full Text Available Abstract Background A number of studies, notably EPIC, have shown a descrease in colorectal cancer risk associated with increased fibre consumption. Whilst the underlying mechanisms are likely to be multifactorial, production of the short-chain fatty-acid butyrate fro butyratye is frequently cited as a major potential contributor to the effect. Butyrate inhibits histone deacetylases, which work on a wide range of proteins over and above histones. We therefore hypothesized that alterations in the acetylated proteome may be associated with a cancer risk phenotype in the colorectal mucosa, and that such alterations are candidate biomarkers for effectiveness of fibre interventions in cancer prevention. Methods an design There are two principal arms to this study: (i a cross-sectional study (FACT OBS of 90 subjects recruited from gastroenterology clinics and; (ii an intervention trial in 40 subjects with an 8 week high fibre intervention. In both studies the principal goal is to investigate a link between fibre intake, SCFA production and global protein acetylation. The primary measure is level of faecal butyrate, which it is hoped will be elevated by moving subjects to a high fibre diet. Fibre intakes will be estimated in the cross-sectional group using the EPIC Food Frequency Questionnaire. Subsidiary measures of the effect of butyrate on colon mucosal function and pre-cancerous phenotype will include measures of apoptosis, apoptotic regulators cell cycle and cell division. Discussion This study will provide a new level of mechanistic data on alterations in the functional proteome in response to the colon microenvironment which may underwrite the observed cancer preventive effect of fibre. The study may yield novel candidate biomarkers of fibre fermentation and colon mucosal function. Trial Registration Trial Registration Number: ISRCTN90852168

  6. A study protocol to investigate the relationship between dietary fibre intake and fermentation, colon cell turnover, global protein acetylation and early carcinogenesis: the FACT study

    International Nuclear Information System (INIS)

    Corfe, Bernard M; Williams, Elizabeth A; Bury, Jonathan P; Riley, Stuart A; Croucher, Lisa J; Lai, Daphne YL; Evans, Caroline A

    2009-01-01

    A number of studies, notably EPIC, have shown a descrease in colorectal cancer risk associated with increased fibre consumption. Whilst the underlying mechanisms are likely to be multifactorial, production of the short-chain fatty-acid butyrate fro butyratye is frequently cited as a major potential contributor to the effect. Butyrate inhibits histone deacetylases, which work on a wide range of proteins over and above histones. We therefore hypothesized that alterations in the acetylated proteome may be associated with a cancer risk phenotype in the colorectal mucosa, and that such alterations are candidate biomarkers for effectiveness of fibre interventions in cancer prevention. There are two principal arms to this study: (i) a cross-sectional study (FACT OBS) of 90 subjects recruited from gastroenterology clinics and; (ii) an intervention trial in 40 subjects with an 8 week high fibre intervention. In both studies the principal goal is to investigate a link between fibre intake, SCFA production and global protein acetylation. The primary measure is level of faecal butyrate, which it is hoped will be elevated by moving subjects to a high fibre diet. Fibre intakes will be estimated in the cross-sectional group using the EPIC Food Frequency Questionnaire. Subsidiary measures of the effect of butyrate on colon mucosal function and pre-cancerous phenotype will include measures of apoptosis, apoptotic regulators cell cycle and cell division. This study will provide a new level of mechanistic data on alterations in the functional proteome in response to the colon microenvironment which may underwrite the observed cancer preventive effect of fibre. The study may yield novel candidate biomarkers of fibre fermentation and colon mucosal function. Trial Registration Number: ISRCTN90852168

  7. Effect of rigid corneal contact lens and corneal limbal stem cell transplantation for senile patients with pterygium

    Directory of Open Access Journals (Sweden)

    Jiang Lu

    2017-06-01

    Full Text Available AIM: To investigate the effect of rigid contact lens in the treatment after pterygium excision and limbal stem cell transplantation in senile patients. METHODS: Totally 90 elderly patients diagnosed as unilateral pterygium in our hospital from March 2015 to March 2016 were selected and divided into two groups, observation group and control group, 45 case with 45 eyes in each group. Observation group was treated with limbal stem cell transplantation and rigid contact lens. Control group was treated with limbal stem cell transplantation only. The following indicators were observed and compared: corneal healing time, visual analogue score(VASat 1, 3, 5 and 7d after surgery and the recurrence rate of pterygium. RESULTS: The score on corneal irritation of observation group was significantly lower than that of control group(PPPP>0.05.CONCLUSION: Autologous corneal stem cell transplantation combined with rigid contact lens for pterygium in elderly patients is effective with shorter healing time and less pain, and it does not increase the recurrence rate.

  8. Fibre-optical microendoscopy.

    Science.gov (United States)

    Gu, M; Bao, H; Kang, H

    2014-04-01

    Microendoscopy has been an essential tool in exploring micro/nano mechanisms in vivo due to high-quality imaging performance, compact size and flexible movement. The investigations into optical fibres, micro-scanners and miniature lens have boosted efficiencies of remote light delivery to sample site and signal collection. Given the light interaction with materials in the fluorescence imaging regime, this paper reviews two classes of compact microendoscopy based on a single fibre: linear optical microendoscopy and nonlinear optical microendoscopy. Due to the fact that fluorescence occurs only in the focal volume, nonlinear optical microendoscopy can provide stronger optical sectioning ability than linear optical microendoscopy, and is a good candidate for deep tissue imaging. Moreover, one-photon excited fluorescence microendoscopy as the linear optical microendoscopy suffers from severe photobleaching owing to the linear dependence of photobleaching rate on excitation laser power. On the contrary, nonlinear optical microendoscopy, including two-photon excited fluorescence microendoscopy and second harmonic generation microendoscopy, has the capability to minimize or avoid the photobleaching effect at a high excitation power and generate high image contrast. The combination of various nonlinear signals gained by the nonlinear optical microendoscopy provides a comprehensive insight into biophenomena in internal organs. Fibre-optical microendoscopy overcomes physical limitations of traditional microscopy and opens up a new path to achieve early cancer diagnosis and microsurgery in a minimally invasive and localized manner. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  9. Dietary Fibre

    NARCIS (Netherlands)

    Kamp, van der J.W.; Asp, N.G.; Miller Jones, J.; Schaafsma, G.

    2004-01-01

    In this book invited expert scientists of leading research groups all over the world will address the following issues: Definitions, health claims and new challenges, Analytical tools, technological aspects and applications, Health Benefits of dietary fibre, including both authoritative generic

  10. Investigation of CIS/CIGS and CdTe solar cells scribing with high-power fibre short pulse lasers

    Science.gov (United States)

    Hernandez, Yves; Lotter, Erwin; Bermudez, Veronica; Bosio, Alessio; Salin, François; Hueske, Marc; Selleri, Stefano; Bertrand, Anthony; Duterte, Charles

    2012-06-01

    We present here some of the last results of the EUROPEAN project ALPINE. We present both the development of an adjustable fibre laser pulse source and scribing results on CdTe and CIGS solar cells. The scribing tests were performed at three different pulse durations: 400 fs, 8 ps and 250 ps. The results obtained with 250 ps are already very promising for P3 steps in both CdTe and CIGS solar cells. In both cases the results were validated electrically. In the case of P3 scribing for CIGS solar cells, shunt resistances as high as 125 kΩ.cm were obtained. Isolation resistances were higher than 1 MΩ.cm. The processing speed was 2 m/s.

  11. Raman micro-spectroscopy analysis of human lens epithelial cells exposed to a low-dose-range of ionizing radiation

    Science.gov (United States)

    Allen, Christian Harry; Kumar, Achint; Qutob, Sami; Nyiri, Balazs; Chauhan, Vinita; Murugkar, Sangeeta

    2018-01-01

    Recent findings in populations exposed to ionizing radiation (IR) indicate dose-related lens opacification occurs at much lower doses (micro-spectroscopy was used to investigate the effects of varying doses of radiation, ranging from 0.01 Gy to 5 Gy, on human lens epithelial (HLE) cells which were chemically fixed 24 h post-irradiation. Raman spectra were acquired from the nucleus and cytoplasm of the HLE cells. Spectra were collected from points in a 3  ×  3 grid pattern and then averaged. The raw spectra were preprocessed and principal component analysis followed by linear discriminant analysis was used to discriminate between dose and control for 0.25, 0.5, 2, and 5 Gy. Using leave-one-out cross-validation accuracies of greater than 74% were attained for each dose/control combination. The ultra-low doses 0.01 and 0.05 Gy were included in an analysis of band intensities for Raman bands found to be significant in the linear discrimination, and an induced repair model survival curve was fit to a band-difference-ratio plot of this data, suggesting HLE cells undergo a nonlinear response to low-doses of IR. A survival curve was also fit to clonogenic assay data done on the irradiated HLE cells, showing a similar nonlinear response.

  12. Raman micro-spectroscopy analysis of human lens epithelial cells exposed to a low-dose-range of ionizing radiation.

    Science.gov (United States)

    Allen, Christian Harry; Kumar, Achint; Qutob, Sami; Nyiri, Balazs; Chauhan, Vinita; Murugkar, Sangeeta

    2018-01-09

    Recent findings in populations exposed to ionizing radiation (IR) indicate dose-related lens opacification occurs at much lower doses (micro-spectroscopy was used to investigate the effects of varying doses of radiation, ranging from 0.01 Gy to 5 Gy, on human lens epithelial (HLE) cells which were chemically fixed 24 h post-irradiation. Raman spectra were acquired from the nucleus and cytoplasm of the HLE cells. Spectra were collected from points in a 3  ×  3 grid pattern and then averaged. The raw spectra were preprocessed and principal component analysis followed by linear discriminant analysis was used to discriminate between dose and control for 0.25, 0.5, 2, and 5 Gy. Using leave-one-out cross-validation accuracies of greater than 74% were attained for each dose/control combination. The ultra-low doses 0.01 and 0.05 Gy were included in an analysis of band intensities for Raman bands found to be significant in the linear discrimination, and an induced repair model survival curve was fit to a band-difference-ratio plot of this data, suggesting HLE cells undergo a nonlinear response to low-doses of IR. A survival curve was also fit to clonogenic assay data done on the irradiated HLE cells, showing a similar nonlinear response.

  13. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

  14. Ankyrin-B directs membrane tethering of periaxin and is required for maintenance of lens fiber cell hexagonal shape and mechanics.

    Science.gov (United States)

    Maddala, Rupalatha; Walters, Mark; Brophy, Peter J; Bennett, Vann; Rao, Ponugoti V

    2016-01-15

    Periaxin (Prx), a PDZ domain protein expressed preferentially in myelinating Schwann cells and lens fibers, plays a key role in membrane scaffolding and cytoarchitecture. Little is known, however, about how Prx is anchored to the plasma membrane. Here we report that ankyrin-B (AnkB), a well-characterized adaptor protein involved in linking the spectrin-actin cytoskeleton to integral membrane proteins, is required for membrane association of Prx in lens fibers and colocalizes with Prx in hexagonal fiber cells. Under AnkB haploinsufficiency, Prx accumulates in the soluble fraction with a concomitant loss from the membrane-enriched fraction of mouse lenses. Moreover, AnkB haploinsufficiency induced age-dependent disruptions in fiber cell hexagonal geometry and radial alignment and decreased compressive stiffness in mouse lenses parallel to the changes observed in Prx null mouse lens. Both AnkB- and Prx-deficient mice exhibit disruptions in membrane organization of the spectrin-actin network and the dystrophin-glycoprotein complex in lens fiber cells. Taken together, these observations reveal that AnkB is required for Prx membrane anchoring and for maintenance of lens fiber cell hexagonal geometry, membrane skeleton organization, and biomechanics. Copyright © 2016 the American Physiological Society.

  15. Downregulation of Smac attenuates H2O2-induced apoptosis via endoplasmic reticulum stress in human lens epithelial cells.

    Science.gov (United States)

    De-Qian, Kong; Yue, Liu; Li, Li; Guangying, Zheng

    2017-07-01

    Second mitochondria-derived activator of caspases (Smac) is reported to promote apoptosis. Given the important role of apoptosis in cataract development, the aim of this study was to investigate whether Smac induces human lens epithelial cell (HLEC) apoptosis via endoplasmic reticulum stress (ERS). Smac expression was examined by immunohistochemistry in anterior lens capsules from 157 patients with age-related cataracts and 5 normal controls. The role of Smac in hydrogen peroxide (H2O2)-induced ERS and apoptosis was further evaluated using small interfering RNA knockdown in an HLEC line. Notably, Smac expression was significantly higher in patients with cataracts than in controls, but showed no association with cataract severity. Cell survival was inversely correlated with H2O2 concentration, and was most significantly affected at 200 μmol/L. Moreover, flow cytometry revealed that Smac knockdown attenuated H2O2-induced apoptosis and enhanced apoptotic- and endoplasmic reticulum-related marker expression-including that of glucose-regulated protein 78, C/EBP homologous protein, caspase 3, B-cell chronic lymphocytic leukemia/lymphoma 2-associated X, and BCL2-at the gene and protein level. Collectively, these results indicate that Smac plays an important role in ERS-induced apoptosis in HLECs, suggesting its close association with cataract development.

  16. Interaction of intraocular lenses with fibronectin and human lens epithelial cells: Effect of chemical composition and aging.

    Science.gov (United States)

    Tortolano, Lionel; Serrano, Carole; Jubeli, Emile; Saunier, Johanna; Yagoubi, Najet

    2015-12-01

    The aim of this study is to investigate in vitro interactions between hydrophobic acrylate intraocular lenses (IOLs) and their biological environment. The influence of lens chemical composition and aging on fibronectin (FN) adsorption and on IOLs cytotoxicity on human lens epithelial cells was examined. Cytotoxicity of acrylate monomers used in IOLs manufacture was also investigated. Four different IOLs were included in the study: Acrysof(®), Tecnis(®), EnVista(®), and iSert(®). Implants were artificially aged in a xenon arc chamber to simulate 2 years of light exposure. Fibronectin adsorption on IOL surface was quantified using ELISA and correlated to surface roughness determined with AFM. Direct contact cytotoxicity was determined with the MTT assay and cell morphology was observed with light microscopy. Results showed that fibronectin adsorption did not differ significantly among IOLs, whatever their chemical composition. Moreover, aging conditions did not impact fibronectin adsorption. All IOLs were biocompatible even after applying 2-year aging conditions, with cell viability higher than 70%. Five acrylate monomers appeared to be toxic in the range of concentrations tested, but no monomer release from the IOLs could be detected during accelerated 2-year incubation with saline solution. This study did not reveal an influence of chemical composition and aging on protein adsorption and on biocompatibility. © 2015 Wiley Periodicals, Inc.

  17. Electron microscopic study of the myelinated nerve fibres and the perineurial cell basement membrane in the diabetic human peripheral nerves

    International Nuclear Information System (INIS)

    ElBarrany, Wagih G.; Hamdy, Raid M.; AlHayani, Abdulmonem A.; Jalalah, Sawsan M.

    2009-01-01

    To study the quantitative and ultrastructural changes in myelinated nerve fibers and the basement membranes of the perineurial cells in diabetic nerves. The study was performed at the Department of Anatomy, Faculty of Medicine, King Abdul-Aziz University, Jeddah, Saudi Arabia from 2003 to 2005. Human sural nerves were obtained from 15 lower limbs and 5 diabetic nerve biopsies. The total mean and density of myelinated nerve fibers per fascicle were calculated, with density of microtubules and mitochondria in the axoplasm. The number of the perineurial cell basement membrane layers was counted, and thickness of the basement membrane was measured. Among the 15 diabetic and 5 normal human sural nerves, the average diameters, number and surface area of myelinated nerve fibers and axonal microtubules density were found to be less in diabetic nerves. Mitochondrial density was higher in diabetic axons. Thickness of the perineurial cell basement membrane had a greater mean, but the number of perineurial cell layers was less than that of the diabetic group. The inner cellular layer of the perineurium of the diabetic nerves contained large vacuoles containing electron-dense degenerated myelin. A few specimens showed degenerated myelinated nerve fibers, while others showed recovering ones. Retracted axoplasms were encountered with albumin extravasation. Diabetes caused an increase in perineurial permeability. The diabetic sural nerve showed marked decrease in the myelinated nerve fibres, increase degenerated mitochondria, and decreased microtubules. (author)

  18. Ectopic activation of Wnt/beta-catenin sgnaling in lens fiber cells results in cataract formation and aberrant fiber cell differentiation

    Czech Academy of Sciences Publication Activity Database

    Antošová, Barbora; Smolíková, Jana; Bořkovcová, Romana; Strnad, Hynek; Láchová, Jitka; Machoň, Ondřej; Kozmik, Zbyněk

    2013-01-01

    Roč. 8, č. 10 (2013), e78279 E-ISSN 1932-6203 R&D Projects: GA ČR GAP305/11/2198; GA ČR GAP305/12/2042; GA MŠk(CZ) LK11214; GA MŠk EE2.3.30.0027 Institutional support: RVO:68378050 Keywords : beta-catenin signaling * cataract * cell differentiation * lens * transcription factor * cyclin Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.534, year: 2013

  19. Scintillating fibres

    International Nuclear Information System (INIS)

    Nahnhauer, R.

    1990-01-01

    In the search for new detector techniques, scintillating fibre technology has already gained a firm foothold, and is a strong contender for the extreme experimental conditions of tomorrow's machines. Organized by a group from the Institute of High Energy Physics, Berlin-Zeuthen, a workshop held from 3-5 September in the nearby village of Blossin brought together experts from East and West, and from science and industry

  20. Stability of mineral fibres in contact with human cell cultures. An in situ μXANES, μXRD and XRF iron mapping study.

    Science.gov (United States)

    Pollastri, Simone; Gualtieri, Alessandro F; Vigliaturo, Ruggero; Ignatyev, Konstantin; Strafella, Elisabetta; Pugnaloni, Armanda; Croce, Alessandro

    2016-12-01

    Relevant mineral fibres of social and economic importance (chrysotile UICC, crocidolite UICC and a fibrous erionite from Jersey, Nevada, USA) were put in contact with cultured diploid human non-tumorigenic bronchial epithelial (Beas2B) and pleural transformed mesothelial (MeT5A) cells to test their cytotoxicity. Slides of each sample at different contact times up to 96 h were studied in situ using synchrotron XRF, μ-XRD and μ-XAS (I18 beamline, Diamond Light Source, UK) and TEM investigations. XRF maps of samples treated for 96 h evidenced that iron is still present within the chrysotile and crocidolite fibres and retained at the surface of the erionite fibres, indicating its null to minor mobilization in contact with cell media; this picture was confirmed by the results of XANES pre-edge analyses. μ-XRD and TEM data indicate greater morphological and crystallinity modifications occurring in chrysotile, whereas crocidolite and erionite show to be resistant in the biological environment. The contact of chrysotile with the cell cultures seems to lead to earlier amorphization, interpreted as the first dissolution step of these fibres. The formation of such silica-rich fibre skeleton may prompt the production of HO in synergy with surface iron species and could indicate that chrysotile may be much more reactive and cytotoxic in vitro in the (very) short term whereas the activity of crocidolite and erionite would be much more sluggish but persistent in the long term. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Lutein and zeaxanthin supplementation reduces H2O2-induced oxidative damage in human lens epithelial cells

    Science.gov (United States)

    Gao, Shasha; Qin, Tingyu; Liu, Zhenzhen; Caceres, Maria Andrea; Ronchi, Carlos F.; Chen, C-Y. Oliver; Yeum, Kyung-jin; Taylor, Allen; Blumberg, Jeffery B.; Liu, Yizhi

    2011-01-01

    Purpose Epidemiological studies suggest that dietary intake of lutein and zeaxanthin is inversely related to the risk for senile cataract. The objectives of this work were to investigate the mechanisms by which these nutrients provide anti-cataract effects. We evaluated their modulation of oxidative damage in human lens epithelial cells (HLEC) and their interaction with intracellular glutathione (GSH). Methods Subconfluent HLEC were pre-incubated with or without 5 µM lutein, zeaxanthin, or α-tocopherol for 48 h and then exposed to 100 µM H2O2 for 1 h. Levels of protein carbonyls in the cells were measured by western-blotting analysis following reaction with 2,4-dinitrophenylhydrazine (DNPH). Levels of malondialdehyde (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSG) were measured by an HPLC system. DNA damage was assessed using comet assays. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Results In the absence of H2O2, HLEC had very low levels of protein carbonyl and MDA. Supplementation with lutein, zeaxanthin, or α-tocopherol to the unstressed HLEC had no detectable effects on levels of oxidized proteins and lipid in the cells. Exposure of HLEC to H2O2 significantly increased levels of oxidized proteins, lipid peroxidation, and DNA damage. Pre-incubation with lutein, zeaxanthin, or α-tocopherol dramatically reduced the levels of H2O2 -induced protein carbonyl, MDA, and DNA damage in HLEC. The protective effects of lutein, zeaxanthin, and α-tocopherol against protein oxidation, lipid peroxidation, and DNA damage were comparable. Supplementation with lutein, zeaxanthin, or α-tocopherol increased GSH levels and GSH:GSSG ratio, particularly in response to oxidative stress. Depletion of GSH resulted in significant increase in susceptibility to H2O2-induced cell death. Supplementation with α-tocopherol, but not lutein or zeaxanthin, can partially restore the

  2. The mechanism of pleural inflammation by long carbon nanotubes: interaction of long fibres with macrophages stimulates them to amplify pro-inflammatory responses in mesothelial cells

    Directory of Open Access Journals (Sweden)

    Murphy Fiona A

    2012-04-01

    Full Text Available Abstract Carbon nanotubes (CNT are high aspect ratio nanoparticles with diameters in the nanometre range but lengths extending up to hundreds of microns. The structural similarities between CNT and asbestos have raised concern that they may pose a similar inhalation hazard. Recently CNT have been shown to elicit a length-dependent, asbestos-like inflammatory response in the pleural cavity of mice, where long fibres caused inflammation but short fibres did not. However the cellular mechanisms governing this response have yet to be elucidated. This study examined the in vitro effects of a range of CNT for their ability to stimulate the release of the acute phase cytokines; IL-1β, TNFα, IL-6 and the chemokine, IL-8 from both Met5a mesothelial cells and THP-1 macrophages. Results showed that direct exposure to CNT resulted in significant cytokine release from the macrophages but not mesothelial cells. This pro-inflammatory response was length dependent but modest and was shown to be a result of frustrated phagocytosis. Furthermore the indirect actions of the CNT were examined by treating the mesothelial cells with conditioned media from CNT-treated macrophages. This resulted in a dramatic amplification of the cytokine release from the mesothelial cells, a response which could be attenuated by inhibition of phagocytosis during the initial macrophage CNT treatments. We therefore hypothesise that long fibres elicit an inflammatory response in the pleural cavity via frustrated phagocytosis in pleural macrophages. The activated macrophages then stimulate an amplified pro-inflammatory cytokine response from the adjacent pleural mesothelial cells. This mechanism for producing a pro-inflammatory environment in the pleural space exposed to long CNT has implications for the general understanding of fibre-related pleural disease and design of safe nanofibres.

  3. A Two-Stage Taguchi Design ExampleImage Quality Promotion in Miniature Camera/Cell-Phone Lens

    Directory of Open Access Journals (Sweden)

    Luke K. Wang

    2012-07-01

    Full Text Available A simple, practical manufacturing process, integrating manufacturing capability-oriented design (MCOD philosophy and Taguchi’s method, is presented to tackle the high resolution miniature camera/cell phone lens issues at the manufacturing phase. Meanwhile, we also use optical software to create an analytical simulation model to investigate the quality characteristics due to lens’ thickness, eccentricity, surface profile, and air lens’ gap; a single quality characteristics expressed in terms of modulation transfer function (MTF is defined. Optimal combination of process parameters in experimental scenario using Taguchi’s method is performed, and the results are judged and analyzed by the indices of signal-to-noise ratio (S/N and the analysis of variance (ANOVA. The key idea of the two-stage design is to utilize optical software to conduct the sensitivity analysis of MTF first; an analytical model, dependent on actual process parameters at manufacturing stage, is constructed next; and finally by substituting these outputs from the analytical model back to the optical software to verify the design criterion and do the modifications. By minimizing both the theoretical errors at design stage and the complexity in the manufacturing process, we are able to seeking for the most economical solution, simultaneously attain the optimal/suboptimal combination of process parameters or control factors in lens manufacturing issue.

  4. Iron-related toxicity of single-walled carbon nanotubes and crocidolite fibres in human mesothelial cells investigated by Synchrotron XRF microscopy.

    Science.gov (United States)

    Cammisuli, Francesca; Giordani, Silvia; Gianoncelli, Alessandra; Rizzardi, Clara; Radillo, Lucia; Zweyer, Marina; Da Ros, Tatiana; Salomé, Murielle; Melato, Mauro; Pascolo, Lorella

    2018-01-15

    Carbon nanotubes (CNTs) are promising products in industry and medicine, but there are several human health concerns since their fibrous structure resembles asbestos. The presence of transition metals, mainly iron, in the fibres seems also implicated in the pathogenetic mechanisms. To unravel the role of iron at mesothelial level, we compared the chemical changes induced in MeT-5A cells by the exposure to asbestos (crocidolite) or CNTs at different content of iron impurities (raw-SWCNTs, purified- and highly purified-SWCNTs). We applied synchrotron-based X-Ray Fluorescence (XRF) microscopy and soft X-ray imaging (absorption and phase contrast images) to monitor chemical and morphological changes of the exposed cells. In parallel, we performed a ferritin assay. X-ray microscopy imaging and XRF well localize the crocidolite fibres interacting with cells, as well as the damage-related morphological changes. Differently, CNTs presence could be only partially evinced by low energy XRF through carbon distribution and sometimes iron co-localisation. Compared to controls, the cells treated with raw-SWCNTs and crocidolite fibres showed a severe alteration of iron distribution and content, with concomitant stimulation of ferritin production. Interestingly, highly purified nanotubes did not altered iron metabolism. The data provide new insights for possible CNTs effects at mesothelial/pleural level in humans.

  5. FoxO3a Serves as a Biomarker of Oxidative Stress in Human Lens Epithelial Cells under Conditions of Hyperglycemia.

    Directory of Open Access Journals (Sweden)

    Ilangovan Raju

    Full Text Available Forkhead box 'O' transcription factors (FoxOs are implicated in the pathogenesis of type2 diabetes and other metabolic diseases. Abnormal activity of FoxOs was reported in the glucose and insulin metabolism. Expression of FoxO proteins was reported in ocular tissues; however their function under hyperglycemic conditions was not examined.Human lens epithelial cell line was used to study the function of FoxO proteins. Immunofluorescence, flow cytometry and Western blotting were employed to detect the FoxO proteins under the conditions of hyperglycemia.In this study we examined the role of FoxO3a in hyperglycemia-induced oxidative stress in human lens epithelial cells. FoxO3a protein expression was elevated in a dose- and time-dependent fashion after high glucose treatment. Anti-oxidant defense mechanisms of the lens epithelial cells were diminished as evidenced from loss of mitochondrial membrane integrity and lowered MnSOD after 72 h treatment with high glucose. Taken together, FoxO3a acts as a sensitive indicator of oxidative stress and cell homeostasis in human lens epithelial cells during diabetic conditions.FoxO3a is an early stress response protein to glucose toxicity in diabetic conditions.

  6. Cultivation and characterization of cornea limbal epithelial stem cells on lens capsule in animal material-free medium.

    Directory of Open Access Journals (Sweden)

    Réka Albert

    Full Text Available A simple, reproducible, animal-material free method for cultivating and characterizing cornea limbal epithelial stem cells (LESCs on human lens capsule (LC was developed for future clinical transplantation. The limbal tissue explants (2 × 2 × 0.25 mm were harvested from 77 cadavers and expanded ex vivo on either cell culture plates or LC in medium containing human serum as the only growth supplement. Cell outgrowth at the edge of the explants was observed within 24 hours of cultivation and achieved viable outgrowth (>97% viability as measured by MTT assay and flow cytometry within two weeks. The outgrowing cells were examined by genome-wide microarray including markers of stemness (p63α, ABCG2, CK19, Vimentin and Integrin α9, proliferation (Ki-67, limbal epithelial cells (CK 8/18 and 14 and differentiated cornea epithelial cells (CK 3 and 12. Immunostaining revealed the non-hematopoietic, -endothelial and -mesenchymal stem cell phenotype of the LESCs and the localization of specific markers in situ. Cell adhesion molecules, integrins and lectin-based surface carbohydrate profiling showed a specific pattern on these cells, while colony-formation assay confirmed their clonal potency. The LESCs expressed a specific surface marker fingerprint (CD117/c-kit, CXCR4, CD144/VE-Cadherin, CD146/MCAM, CD166/ALCAM, and surface carbohydrates: WGA, ConA, RCA, PNA and AIL which can be used for better localization of the limbal stem cell niche. In summary, we report a novel method combining the use of a medium with human serum as the only growth supplement with LC for cultivating, characterizing and expanding cornea LESCs from cadavers or alternatively from autologous donors for possible treatment of LESC deficiency.

  7. Cultivation and characterization of cornea limbal epithelial stem cells on lens capsule in animal material-free medium.

    Science.gov (United States)

    Albert, Réka; Veréb, Zoltán; Csomós, Krisztián; Moe, Morten C; Johnsen, Erik O; Olstad, Ole Kristoffer; Nicolaissen, Bjørn; Rajnavölgyi, Eva; Fésüs, László; Berta, András; Petrovski, Goran

    2012-01-01

    A simple, reproducible, animal-material free method for cultivating and characterizing cornea limbal epithelial stem cells (LESCs) on human lens capsule (LC) was developed for future clinical transplantation. The limbal tissue explants (2 × 2 × 0.25 mm) were harvested from 77 cadavers and expanded ex vivo on either cell culture plates or LC in medium containing human serum as the only growth supplement. Cell outgrowth at the edge of the explants was observed within 24 hours of cultivation and achieved viable outgrowth (>97% viability as measured by MTT assay and flow cytometry) within two weeks. The outgrowing cells were examined by genome-wide microarray including markers of stemness (p63α, ABCG2, CK19, Vimentin and Integrin α9), proliferation (Ki-67), limbal epithelial cells (CK 8/18 and 14) and differentiated cornea epithelial cells (CK 3 and 12). Immunostaining revealed the non-hematopoietic, -endothelial and -mesenchymal stem cell phenotype of the LESCs and the localization of specific markers in situ. Cell adhesion molecules, integrins and lectin-based surface carbohydrate profiling showed a specific pattern on these cells, while colony-formation assay confirmed their clonal potency. The LESCs expressed a specific surface marker fingerprint (CD117/c-kit, CXCR4, CD144/VE-Cadherin, CD146/MCAM, CD166/ALCAM, and surface carbohydrates: WGA, ConA, RCA, PNA and AIL) which can be used for better localization of the limbal stem cell niche. In summary, we report a novel method combining the use of a medium with human serum as the only growth supplement with LC for cultivating, characterizing and expanding cornea LESCs from cadavers or alternatively from autologous donors for possible treatment of LESC deficiency.

  8. Analysis of the Anti-Cancer Effects of Cincau Extract (Premna oblongifolia Merr) and Other Types of Non-Digestible Fibre Using Faecal Fermentation Supernatants and Caco-2 Cells as a Model of the Human Colon

    Science.gov (United States)

    Nurdin, Samsu U.; Le Leu, Richard K.; Young, Graeme P.; Stangoulis, James C. R.; Christophersen, Claus T.; Abbott, Catherine A.

    2017-01-01

    Green cincau (Premna oblongifolia Merr) is an Indonesian food plant with a high dietary fibre content. Research has shown that dietary fibre mixtures may be more beneficial for colorectal cancer prevention than a single dietary fibre type. The aim of this study was to investigate the effects of green cincau extract on short chain fatty acid (SCFA) production in anaerobic batch cultures inoculated with human faecal slurries and to compare these to results obtained using different dietary fibre types (pectin, inulin, and cellulose), singly and in combination. Furthermore, fermentation supernatants (FSs) were evaluated in Caco-2 cells for their effect on cell viability, differentiation, and apoptosis. Cincau increased total SCFA concentration by increasing acetate and propionate, but not butyrate concentration. FSs from all dietary fibre sources, including cincau, reduced Caco-2 cell viability. However, the effects of all FSs on cell viability, cell differentiation, and apoptosis were not simply explainable by their butyrate content. In conclusion, products of fermentation of cincau extracts induced cell death, but further work is required to understand the mechanism of action. This study demonstrates for the first time that this Indonesian traditional source of dietary fibre may be protective against colorectal cancer. PMID:28368356

  9. Cytogenetic effects of 48titanium (48ti) on meristematic cells of root tips of lens culinaris med

    International Nuclear Information System (INIS)

    Sepet, H.; Bozdag, B.

    2014-01-01

    Cytogenetic effects of 48Titanium (48Ti) on meristematic cells of root tips belonging to the plant (Lens culinaris Medik.) have been Investigated. Seeds of the plant, prepared were kept in 48Ti standart for different time period as control during 1/4, 1/2, 1, 2, 4, 8, 12, 16, 20, 24 hours. Seeds treated with 48Ti were made sprout and the root tips obtained were prepared for microscopic examination. At the end of the microscopic examinations, some abnormalities as chromosome breakings, chromosome dispersion, bridge chromosome, chromosome adherence, ring chromosome were observed. Abnormalities were seen at each treatment depended on the time periods. Variety and number of abnormality were usually seen to be increasing, depending on the increase of treatment time. The results obtained were evaluated statistically. (author)

  10. Synapses between parallel fibres and stellate cells express long-term changes in synaptic efficacy in rat cerebellum.

    Science.gov (United States)

    Rancillac, Armelle; Crépel, Francis

    2004-02-01

    Various forms of synaptic plasticity underlying motor learning have already been well characterized at cerebellar parallel fibre (PF)-Purkinje cell (PC) synapses. Inhibitory interneurones play an important role in controlling the excitability and synchronization of PCs. We have therefore tested the possibility that excitatory synapses between PFs and stellate cells (SCs) are also able to exhibit long-term changes in synaptic efficacy. In the present study, we show that long-term potentiation (LTP) and long-term depression (LTD) were induced at these synapses by a low frequency stimulation protocol (2 Hz for 60 s) and that pairing this low frequency stimulation protocol with postsynaptic depolarization induced a marked shift of synaptic plasticity in favour of LTP. This LTP was cAMP independent, but required nitric oxide (NO) production from pre- and/or postsynaptic elements, depending on the stimulation or pairing protocol used, respectively. In contrast, LTD was not dependent on NO production but it required activation of postsynaptic group II and possibly of group I metabotropic glutamate receptors. Finally, stimulation of PFs at 8 Hz for 15 s also induced LTP at PF-SC synapses. But in this case, LTP was cAMP dependent, as was also observed at PF-PC synapses for presynaptic LTP induced in the same conditions. Thus, long-term changes in synaptic efficacy can be accomplished by PF-SCs synapses as well as by PF-PC synapses, suggesting that both types of plasticity might co-operate during cerebellar motor learning.

  11. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory...

  12. Semi-analytical representation of the activation level in stress fibre directions as alternative to the angular representation in the bio-chemo-mechanical model for cell contractility.

    Science.gov (United States)

    Bahls, Christian Rüdiger; Truong, Duy; Rienen, Ursula van

    2018-01-01

    The bio-chemo-mechanical model has many applications in modelling cell contractility. In simulations this model usually is coupled to the continuum mechanics of the cell by defining a large number of directions for stress fibres at each point. In this paper, another representation for coupling the biochemical processes in the bio-chemo-mechanical model is introduced. Using a quadratic form to represent the angular dependency of the activation level, the model's number of degrees of freedom is significantly reduced. Numerical results similar to the original representation are obtained while a significant improvement in computation time is achieved. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. αA-crystallin R49Cneo mutation influences the architecture of lens fiber cell membranes and causes posterior and nuclear cataracts in mice

    Directory of Open Access Journals (Sweden)

    Andley Usha P

    2009-07-01

    Full Text Available Abstract Background αA-crystallin (CRYAA/HSPB4, a major component of all vertebrate eye lenses, is a small heat shock protein responsible for maintaining lens transparency. The R49C mutation in the αA-crystallin protein is linked with non-syndromic, hereditary human cataracts in a four-generation Caucasian family. Methods This study describes a mouse cataract model generated by insertion of a neomycin-resistant (neor gene into an intron of the gene encoding mutant R49C αA-crystallin. Mice carrying the neor gene and wild-type Cryaa were also generated as controls. Heterozygous knock-in mice containing one wild type gene and one mutated gene for αA-crystallin (WT/R49Cneo and homozygous knock-in mice containing two mutated genes (R49Cneo/R49Cneo were compared. Results By 3 weeks, WT/R49Cneo mice exhibited large vacuoles in the cortical region 100 μm from the lens surface, and by 3 months posterior and nuclear cataracts had developed. WT/R49Cneo mice demonstrated severe posterior cataracts at 9 months of age, with considerable posterior nuclear migration evident in histological sections. R49Cneo/R49Cneo mice demonstrated nearly complete lens opacities by 5 months of age. In contrast, R49C mice in which the neor gene was deleted by breeding with CreEIIa mice developed lens abnormalities at birth, suggesting that the neor gene may suppress expression of mutant R49C αA-crystallin protein. Conclusion It is apparent that modification of membrane and cell-cell interactions occurs in the presence of the αA-crystallin mutation and rapidly leads to lens cell pathology in vivo.

  14. [The influence of lentivirus-miRNA-184 on epithelial-mesenchcymal transition of human lens epithelial cells in vitro].

    Science.gov (United States)

    Xu, Qing; Li, Zhen; Zhang, Hui

    2015-04-01

    To analyze the influence of miRNA-184 on epithelial-mesenchymal transition (EMT) of human lens epithelial cells (HLEC) induced by TGF-beta2 in vitro. Experimental study. Recombinant plasmid of pL/IRES/GFP-miR-184 was constructed and used to produce the lentivirus. The lentivirus was used to transduce the HLEC which was in the process of EMT induced by transforming growth factor-β2 (TGF-β2). The real-time fluorescence quantitative PCR (QRT-PCR) was used to analyze E-cadherin (CDH1), α-smooth muscle actin (α-SMA), vimentin (VIM) expression at RNA levels during interval of 0 h, 6 h and 24 h after transduction, in comparison with that of control group. Statistical analysis method was single factor variance analysis. The expression level of epithelial marker gene CDH1 in the miRNA-184 transduced group maintains relatively stable during 24h interval, while it goes down in the control group. The expression level of mesenchymal cell marker gene VIM, α-SMA in the miRNA-184 transduced group maintain relatively stable, while it goes up in the control group. The results of statistical analysis showed a statistically significant difference between miRNA-184 transduced group and control group (P184 lentivirus-mediated HLEC can inhibit the occurrence of EMT.

  15. The plant secretory pathway seen through the lens of the cell wall.

    Science.gov (United States)

    van de Meene, A M L; Doblin, M S; Bacic, Antony

    2017-01-01

    Secretion in plant cells is often studied by looking at well-characterised, evolutionarily conserved membrane proteins associated with particular endomembrane compartments. Studies using live cell microscopy and fluorescent proteins have illuminated the highly dynamic nature of trafficking, and electron microscopy studies have resolved the ultrastructure of many compartments. Biochemical and molecular analyses have further informed about the function of particular proteins and endomembrane compartments. In plants, there are over 40 cell types, each with highly specialised functions, and hence potential variations in cell biological processes and cell wall structure. As the primary function of secretion in plant cells is for the biosynthesis of cell wall polysaccharides and apoplastic transport complexes, it follows that utilising our knowledge of cell wall glycosyltransferases (GTs) and their polysaccharide products will inform us about secretion. Indeed, this knowledge has led to novel insights into the secretory pathway, including previously unseen post-TGN secretory compartments. Conversely, our knowledge of trafficking routes of secretion will inform us about polarised and localised deposition of cell walls and their constituent polysaccharides/glycoproteins. In this review, we look at what is known about cell wall biosynthesis and the secretory pathway and how the different approaches can be used in a complementary manner to study secretion and provide novel insights into these processes.

  16. Conjunctival Goblet Cell Function: Effect of Contact Lens Wear and Cytokines

    OpenAIRE

    Garc?a-Posadas, Laura; Contreras-Ruiz, Laura; Soriano-Roman?, Laura; Dartt, Darlene A.; Diebold, Yolanda

    2016-01-01

    This review focuses on conjunctival goblet cells and their essential function in the maintenance of eye health. The main function of goblet cells is to produce and secrete mucins that lubricate the ocular surface. An excess or a defect in those mucins leads to several alterations that makes goblet cells central players in maintaining the proper mucin balance and ensuring the correct function of ocular surface tissues. A typical pathology that occurs with mucous deficiency is dry eye disease, ...

  17. Thermal Lens Microscope

    Science.gov (United States)

    Uchiyama, Kenji; Hibara, Akihide; Kimura, Hiroko; Sawada, Tsuguo; Kitamori, Takehiko

    2000-09-01

    We developed a novel laser microscope based on the thermal lens effect induced by a coaxial beam comprised of excitation and probe beams. The signal generation mechanism was confirmed to be an authentic thermal lens effect from the measurement of signal and phase dependences on optical configurations between the sample and the probe beam focus, and therefore, the thermal lens effect theory could be applied. Two-point spatial resolution was determined by the spot size of the excitation beam, not by the thermal diffusion length. Sensitivity was quite high, and the detection ability, evaluated using a submicron microparticle containing dye molecules, was 0.8 zmol/μm2, hence a distribution image of trace chemical species could be obtained quantitatively. In addition, analytes are not restricted to fluorescent species, therefore, the thermal lens microscope is a promising analytical microscope. A two-dimensional image of a histamine molecule distribution, which was produced in mast cells at the femtomole level in a human nasal mucous polyp, was obtained.

  18. Effects of lentiviral RNA interference-mediated downregulation of integrin-linked kinase on biological behaviors of human lens epithelial cells

    Directory of Open Access Journals (Sweden)

    Yu-Ping Zheng

    2016-01-01

    Full Text Available AIM: To investigate the effects of lentivirus (LV mediated integrin-linked kinase (ILK RNA interference (RNAi on biological behaviors of human lens epithelial cells (LECs. METHODS: Human cataract LECs and immortalized human LEC line, human lens epithelial (HLE B-3 cells were transfected by lentiviral vector expressing ILK-specific short hairpin RNA (shRNA and then stimulated by transforming growth factor- (TGF-, the silencing of ILK gene and protein was identified by reverse transcription-polymerase chain reaction (RT-PCR and Western blot methods; biological behaviors including cell cycle and apoptosis, cell morphology, -smooth muscle actin (SMA stress fiber formation and cell migration were examined. RESULTS: Remarkable decreases of ILK protein expression were detected in LECs carrying lentiviral ILK-shRNA vector; flow cytometry revealed arresting of cell cycle progression through the G1/S transition and higher apoptosis rate in ILK-RNAi-LV transfected cells. Less -SMA stress fiber formation and migration was observed in ILK-RNAi-LV transfected LECs. CONCLUSION: The present study demonstrated that ILK was an important regulator for LECs proliferation and migration. LV mediated ILK RNAi is an effective way to decrease ILK-regulated cell growth by arresting cell cycle progression and increasing cell apoptosis, as well as, to prevent cell migration by inhibiting TGF- induced -SMA stress fiber formation. Thus, LV mediated ILK RNAi might be useful to prevent posterior capsular opacification.

  19. Muscle fibre capillarization is a critical factor in muscle fibre hypertrophy during resistance exercise training in older men.

    Science.gov (United States)

    Snijders, Tim; Nederveen, Joshua P; Joanisse, Sophie; Leenders, Marika; Verdijk, Lex B; van Loon, Luc J C; Parise, Gianni

    2017-04-01

    Adequate muscle fibre perfusion is critical for the maintenance of muscle mass; it is essential in the rapid delivery of oxygen, nutrients and growth factors to the muscle, stimulating muscle fibre growth. Muscle fibre capillarization is known to decrease substantially with advancing age. However, whether (relative) low muscle fibre capillarization negatively impacts the muscle hypertrophic response following resistance exercise training in older adults is unknown. Twenty-two healthy older men (71 ± 1 years) performed 24 weeks of progressive resistance type exercise training. To assess the change in muscle fibre characteristics, percutaneous biopsies from the vastus lateralis muscle were taken before and following 12 and 24 weeks of the intervention programme. A comparison was made between participants who had a relatively low type II muscle fibre capillary-to-fibre perimeter exchange index (CFPE; LOW group) and high type II muscle fibre CFPE (HIGH group) at baseline. Type I and type II muscle fibre size, satellite cell, capillary content and distance between satellite cells to the nearest capillary were determined by immunohistochemistry. Overall, type II muscle fibre size (from 5150 ± 234 to 6719 ± 446 µm 2 , P muscle fibre, P muscle fibre capillarization, whereas muscle fibre size (from 5170 ± 390 to 7133 ± 314 µm 2 , P muscle fibre, P muscle fibre capillarization were observed in response to 12 and 24 weeks of resistance exercise training in both the LOW and HIGH group. Type II muscle fibre capillarization at baseline may be a critical factor for allowing muscle fibre hypertrophy to occur during prolonged resistance exercise training in older men. © 2016 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  20. Acrylic acid surface-modified contact lens for the culture of limbal stem cells.

    Science.gov (United States)

    Zhang, Hong; Brown, Karl David; Lowe, Sue Peng; Liu, Guei-Sheung; Steele, David; Abberton, Keren; Daniell, Mark

    2014-06-01

    Surface treatment to a biomaterial surface has been shown to modify and help cell growth. Our aim was to determine the best surface-modified system for the treatment of limbal stem cell deficiency (LSCD), which would facilitate expansion of autologous limbal epithelial cells, while maintaining cultivated epithelial cells in a less differentiated state. Commercially available contact lenses (CLs) were variously surface modified by plasma polymerization with ratios of acrylic acid to octadiene tested at 100% acrylic acid, 50:50% acrylic acid:octadiene, and 100% octadiene to produce high-, mid-, and no-acid. X-ray photoelectron spectroscopy was used to analyze the chemical composition of the plasma polymer deposited layer. Limbal explants cultured on high acid-modified CLs outgrew more cells. Immunofluorescence and RT2-PCR array results indicated that a higher acrylic acid content can also help maintain progenitor cells during ex vivo expansion of epithelial cells. This study provides the first evidence for the ability of high acid-modified CLs to preserve the stemness and to be used as substrates for the culture of limbal cells in the treatment of LSCD.

  1. Discussion of Animal Stem Cells in the Classroom: Engaging Students through the Lens of Veterinary Medicine

    Science.gov (United States)

    Farenga, Stephen J.; Niess, Daniel; Hutchinson, Michael

    2015-01-01

    Learning about stem cells within the context of treating pet illness or injury is an additional way for teachers to discuss the integration of science, technology, and veterinary medicine. We explain how practitioners in veterinary medicine harvest animal stem cells from adipose (fat) tissue in treating pet illness or injury. Further, we narrate…

  2. Pressure-assisted cell spinning: a direct protocol for spinning biologically viable cell-bearing fibres and scaffolds

    International Nuclear Information System (INIS)

    Arumuganathar, Sumathy; Irvine, Scott; McEwan, Jean R; Jayasinghe, Suwan N

    2007-01-01

    We recently pioneered the ability to directly electrospin living cells from which scaffolds to membranes were derived. This protocol, now widely referred to as 'cell electrospinning', is currently undergoing in-depth investigations where the post-treated cell's global gene expression to its sub-cellular components is being investigated for understanding any effects post-treating. Our motivation is to develop this method for the biomedical sciences, in particular for applications in regenerative and therapeutic medicine. In the current work, we unveil a direct cell spinning protocol which is non-electric field driven and which will compete directly with cell electrospinning. We referred to this processing method as 'pressure-assisted spinning' in our previous studies, where we demonstrated this route as an emerging micro/nanotechnology. In the current context, we refer to this processing protocol as 'pressure-assisted cell spinning' (PACS). Our developmental studies on PACS reported here show, for the first time, that this technique could be explored as an alternative approach to cell electrospinning. Pressure-assisted cell spinning now enters the direct biological scaffold to membrane formation league

  3. Influence of anterior chamber depth, anterior chamber volume, axial length, and lens density on postoperative endothelial cell loss.

    Science.gov (United States)

    Reuschel, Anna; Bogatsch, Holger; Oertel, Nicole; Wiedemann, Renate

    2015-05-01

    To evaluate the influence of anterior chamber depth (ACD), anterior chamber volume (ACV), lens density (LD), and axial length (AL) as risk factors on endothelial cell loss 3 months after cataract surgery. We enrolled 47 patients with senile cataract who were operated between July 2012 and March 2013 by the same surgeon using torsional phacoemulsification. Preoperatively, we measured ACD, ACV, and LD using the Oculus Pentacam®. The AL was determined using the IOL Master®. Primary outcomes were central endothelial density (ECD) and corrected distance visual acuity (CDVA) 3 months after surgery We evaluated the effect of ACD, ACV, LD, and AL as possible risk factors of postoperative percentage endothelial cell loss (ECL). The median age was 72 years. The median CDVA before surgery was 0.5 improving to 1.0 postoperatively. The median ECL was 5.2 % (range 1.7 %-7.6 %). These results are comparable to our previous study (median ECL 6.9 % after 3 months) [Reuschel et al. (2010) J Cataract Refract Surg]. The median ACD in our study was 2.56 mm (range 2.26 mm-2.8 mm). Median ACV was 144 mm(3) (range 121 mm(3)-158 mm(3)]. The median LD was 12.4 (range 11.4-13.7). Median AL was 23.1 mm (range 22.7 mm-23.9 mm). Our correlation analysis showed no significant correlation between ACD, ACV, LD, AL, and postoperative ECL. ACD, ACV, AL, and LD were not identified as risk factors of postoperative endothelial cell loss in our analysis.

  4. [DNA damage and repair induced by acute exposure of microwave from mobile phone on cultured human lens epithelial cells].

    Science.gov (United States)

    Sun, Li-xia; Yao, Ke; Jiang, Huai; He, Ji-liang; Lu, De-qiang; Wang, Kai-jun; Li, Hong-wu

    2006-12-01

    To investigate the effects of acute exposure of low-power 217 Hz modulated 1. 8 GHz microwave radiation on the DNA damage of human lens epithelial cells (hLECs) and repair. Cultured hLECs were exposed to 217 Hz modulated 1. 8 GHz microwave radiation at SAR (specific absorption rate) of 1. 0, 2. 0, 3. O0 and 4. 0 W/kg for 2 hours in an sXc-1800 incubator and irradiate system, the DNA single strand breaks were detected with comet assay ( single-cell gel electrophoresis) in sham-irradiated cells and irradiated cells incubated for varying periods: 0, 30 and 60 minutes after irradiation. Images of comets were digitized and analyzed using an Imagine-pro plus software, and the indexes used in this study were tail length (TL) and tail moment (TM). BrdU was added into the medium with additional one hour incubation after radiation, the cell proliferation rate was determined using a BrdU-kit. The difference of DNA-breaks between the exposure and sham exposure groups induced by 1.0 and 2.0 W/kg irradiation were not significant in each time points (P > 0.05) ; there were significant difference in both groups at the exposure dose of 3. 0 and 4. 0 W/kg immediately and at the time of 30 minutes after irradiation (P 0. 05) compared with control, but the evidence of significant DNA damage still existed in 4. 0 W/kg group at the same time point. Cell proliferation rate had no significant difference when the application of SAR was 0. 05) , however the cell proliferation was decreased significantly at the dose of 4. 0 W/kg irradiation ( P < 0. 01). No effective DNA damage was induced using comet assay after 2 hours irradiation of 1. 8 GHz microwave on hLECs at the dose SAR < or = 3.0 W/kg. 4.0 W/kg irradiation caused significantly DNA damage and inhibition of hLECs proliferation.

  5. Microgel polymer composite fibres

    OpenAIRE

    Kehren, Dominic

    2014-01-01

    In this thesis some novel ideas and advancements in the field of polymer composite fibres, specifically microgel-based polymer composite fibres have been achieved. The main task was to investigate and understand the electrospinning process of microgels and polymers and the interplay of parameter influences, in order to fabricate reproducible and continuously homogenous composite fibres. The main aim was to fabricate a composite material which combines the special properties of polymer fibres ...

  6. ELASTICITY of SHORT FIBRE REINFORCED POLYAMIDE: MORPHOLOGICAL AND NUMERICAl ANALYSIS OF FIBRE ORIENTATION EFFECTS

    Directory of Open Access Journals (Sweden)

    Francesca Cosmi

    2010-10-01

    Full Text Available The fatigue behaviour of injection moulded short fibre reinforced polymers depends upon fibre orientation, as shown in experiments conducted with notched specimens injected through different injection gates. The different fatigue behaviour is mainly related to the different local elastic properties, as determined by the different fibre orientation patterns, resulting into different strain distributions. In order to quantify the relationship between fibre orientation and elastic constants, the Cell Method was applied to volumes extracted from the specimens, reconstructed by micro-tomography.

  7. Protective Effect of Tea Polyphenol Ophthalmic Gel on Lens Epithelial Cells in Rabbits with Silicone Oil Tamponade after Vitrectomy

    Directory of Open Access Journals (Sweden)

    Xianzhen Ma

    2014-01-01

    Full Text Available Purpose. The aim of this study was to investigate the effect of tea polyphenols (TP ophthalmic gel on lens epithelial cells (LECs in rabbits with silicone oil tamponade after vitrectomy. Methods. In this study, unilateral vitrectomy with silicone oil tamponade was performed using 2-month-old New Zealand white rabbits (n = 72; meanwhile, age-matched nonoperated rabbits (n = 18 were used as controls. The TP ophthalmic gel was administered topically in the surgical eyes till they were sacrificed. On days 45 and 90 after operation, the levels of reactive oxygen species (ROS, mitochondrial membrane potential (ΔΨm, and apoptosis of LECs were analyzed, respectively. Meanwhile, caspase-3 mRNA and protein levels were also determined. Results. The results indicate that the levels of ROS and apoptosis were elevated for LECs in rabbits after operation, whereas ΔΨm was decreased. Caspase-3 was apparently increased at both mRNA and protein levels. Treatment of TP ophthalmic gel could reduce the generation of ROS, maintain ΔΨm, inhibit the overexpression of caspase-3, and thus decrease the apoptosis of LECs of rabbits after operation. Conclusions. TP ophthalmic gel can efficiently inhibit caspase-3 overexpression, reduce the apoptosis of LECs, and prevent LECs from damage. Our result provides a new approach to prevent the development of complicated cataract after vitrectomy.

  8. Selenoprotein R Protects Human Lens Epithelial Cells against D-Galactose-Induced Apoptosis by Regulating Oxidative Stress and Endoplasmic Reticulum Stress.

    Science.gov (United States)

    Dai, Jie; Liu, Hongmei; Zhou, Jun; Huang, Kaixun

    2016-02-10

    Selenium is an essential micronutrient for humans. Much of selenium's beneficial influence on health is attributed to its presence within 25 selenoproteins. Selenoprotein R (SelR), known as methionine sulfoxide reductase B1 (MsrB1), is a selenium-dependent enzyme that, like other Msrs, is required for lens cell viability. In order to investigate the roles of SelR in protecting human lens epithelial (hLE) cells against damage, the influences of SelR gene knockdown on d-galactose-induced apoptosis in hLE cells were studied. The results showed that both d-galactose and SelR gene knockdown by siRNA independently induced oxidative stress. When SelR-gene-silenced hLE cells were exposed to d-galactose, glucose-regulated protein 78 (GRP78) protein level was further increased, mitochondrial membrane potential was significantly decreased and accompanied by a release of mitochondrial cytochrome c. At the same time, the apoptosis cells percentage and the caspase-3 activity were visibly elevated in hLE cells. These results suggested that SelR might protect hLE cell mitochondria and mitigating apoptosis in hLE cells against oxidative stress and endoplasmic reticulum (ER) stress induced by d-galactose, implying that selenium as a micronutrient may play important roles in hLE cells.

  9. TUG1 promotes lens epithelial cell apoptosis by regulating miR-421/caspase-3 axis in age-related cataract.

    Science.gov (United States)

    Li, Guoxing; Song, Huiyang; Chen, Lei; Yang, Weihua; Nan, Kaihui; Lu, Peirong

    2017-07-01

    Age-related cataract is among the most common chronic disorders of ageing and the apoptosis of lens epithelial cells contributes to non-congenital cataract development. We amid to explore the role of TUG1 and miR-421 in the age-related cataract. The expression level of TUG1, miR-421 and caspase-3 were detected by RT-qPCR. The apoptotic-related protein, caspase-3, Bax and blc-2 were analyzed by western blot. We performed ultraviolet (UV) irradiation to induce SAR01/04 cell apoptosis which was analyzed by flow cytometry. RIP pull-down and luciferase reporter assay were used to verified the combination and regulating among TUG1, miR-421 and caspase-3. Here, we observed that the expression level of TUG1 and caspase-3 in the anterior lens capsules of age-related cataract were significantly higher and miR-421 was significantly lower than that in the normal anterior lens capsules. The apoptosis-related protein, caspase-3, Bax and blc-2 were abnormal expression in the anterior lens capsules of age-related cataract tissue. Our data showed that the expression level of TUG1 and caspase-3 and cell apoptosis rate in SAR01/04 cells treated with UV irradiation was remarkably higher than that in the control. TUG1 negatively regulated miR-421 expression and promoted UV irradiation-induced SAR01/04 cell apoptosis. However, miR-421 inhibitor and pcDNA-caspase-3 could reverse the action of the SRA01/04 cell apoptosis by si-TUG1, which suggested TUG1 promoted UV irradiation-induced apoptosis through downregulating miR-421 expression. Furthermore, this study confirmed TUG1 could been in combination with miR-421, and TUG1 and caspase-3 were both a directly target of miR-421. TUG1 modulated lens epithelial cell apoptosis through miR-421/caspase-3 axis. These findings will offer a novel insight into the pathogenesis of cataract. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Fun with Optical Fibres

    Science.gov (United States)

    Alti, Kamlesh

    2017-01-01

    Optical fibres play a very crucial role in today's technologies. Academic courses in optical fibres start at the undergraduate level. Nevertheless, student's curiosity towards optical fibres starts from the school level. In this paper, some fun experiments have been designed for both school and college students, which have some concrete…

  11. Solar concentrator modules with silicone-onglass Fresnel lens panels and multijunction cells.

    Science.gov (United States)

    Rumyantsev, Valery D

    2010-04-26

    High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

  12. Solar concentrator modules with silicone-on-glass Fresnel lens panels and multijunction cells.

    Science.gov (United States)

    Rumyantsev, Valery D

    2010-04-26

    High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

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

    Science.gov (United States)

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

    2013-01-01

    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

  14. High-resolution X-ray tomography of the human inner ear: synchrotron radiation-based study of nerve fibre bundles, membranes and ganglion cells.

    Science.gov (United States)

    Lareida, A; Beckmann, F; Schrott-Fischer, A; Glueckert, R; Freysinger, W; Müller, B

    2009-04-01

    The combination of osmium tetroxide staining and high-resolution tomographic imaging using monochromatic X rays allows visualizing cellular structures of the human inner ear, that is, the organ of Corti, the stria vascularis and further soft tissues of the membranous labyrinth, in three-dimensional space with isotropic micrometre resolution. This approach permits to follow the course of nerve fibre bundles in a major part of the specimen and reveals the detailed three-dimensional arrangement of individual ganglion cells with distinct nuclei by means of X-ray tomography for the first time. The non-destructive neuron cell counting in a selected volume of 125 microm x 800 microm x 600 microm = 0.06 mm(3) gives rise to the estimate that 2000 ganglion cells are present along 1 mm organ of Corti.

  15. Microstructured polymer optical fibres

    CERN Document Server

    Large, Maryanne; Barton, Geoff; van Eijkelenborg, Martijn A

    2008-01-01

    Microstructured Polymer Optical Fibres describes the optical properties of microstructured fibres, how they are made and modelled, and outlines some potential applications. These applications include areas where polymer fibres are already used, such as high-data rate transmission for Fibre-to-the Home or within cars, as well as completely new areas such as the photonic bandgap transmission of ""difficult"" wavelengths. Emphasising a conceptual understanding of the underlying physics, Microstructured Polymer Optical Fibres is clearly written, and includes numerous illustrations. It provides an

  16. Fibre illumination system

    DEFF Research Database (Denmark)

    2012-01-01

    Source: EP2426402A The invention relates to a fibre illumination module and system for the collection and delivery of daylight for illumination purposes. The fibre illumination module comprises a plurality of collector elements, each collector element comprising an input fibre having a first end......-directional arrangement. The fibre illumination system comprises a fibre illumination module of the above-mentioned type. By the invention, daylight may be exploited for the illumination of remote interior spaces of buildings in order to save energy, and improve the well-being of users in both housing and working...

  17. Inhibition of hypoxia inducible factor-1α downregulates the expression of epithelial to mesenchymal transition early marker proteins without undermining cell survival in hypoxic lens epithelial cells.

    Science.gov (United States)

    Cammarata, Patrick R; Neelam, Sudha; Brooks, Morgan M

    2015-01-01

    The purpose of this study was to identify potential therapeutic strategies to slow down or prevent the expression of early-onset epithelial to mesenchymal transition (EMT) marker proteins (fibronectin and alpha smooth muscle actin, α-SMA) without sacrificing the synthesis and accumulation of the prosurvival protein vascular endothelial growth factor (VEGF) in cultured virally transformed human lens epithelial (HLE) cells. HLE-B3 cells, maintained in a continuous hypoxic environment (1% oxygen), were treated with SB216763, a specific inhibitor of glycogen synthase kinase-3β (GSK-3β) catalytic activity. Western blot analysis was employed to detect the cytoplasmic and nuclear levels of β-catenin, as well as the total lysate content of fibronectin and α-SMA. Enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of VEGF in cell culture medium. A hypoxia-inducible factor-1α (HIF-1α) translation inhibitor and an HIF-2α translation inhibitor were independently employed to evaluate the effect of hypoxia inducible factor inhibition on EMT marker protein and VEGF expression. XAV932 was used to assess the suppression of nuclear β-catenin and its downstream effect on EMT marker proteins and VEGF expression. SB216763-treated HLE-B3 cells caused marked inhibition of GSK-3β activity prompting a significant increase in the translocation of cytoplasmic β-catenin to the nucleus. The enhancement of nuclear β-catenin looked as if it positively correlated with a significant increase in the basal expression of VEGF as well as increased expression of fibronectin and α-SMA. In conjunction with SB216763, coadministration of an HIF-1α translation inhibitor, but not an HIF-2α translation inhibitor, markedly suppressed the expression of fibronectin and α-SMA without affecting VEGF levels. Treatment with XAV932 significantly reduced the level of nuclear β-catenin, but the levels of neither the EMT marker proteins nor VEGF were changed. Recently, we reported

  18. Computational predictions of the tensile properties of electrospun fibre meshes: effect of fibre diameter and fibre orientation.

    Science.gov (United States)

    Stylianopoulos, Triantafyllos; Bashur, Chris A; Goldstein, Aaron S; Guelcher, Scott A; Barocas, Victor H

    2008-10-01

    The mechanical properties of biomaterial scaffolds are crucial for their efficacy in tissue engineering and regenerative medicine. At the microscopic scale, the scaffold must be sufficiently rigid to support cell adhesion, spreading, and normal extracellular matrix deposition. Concurrently, at the macroscopic scale the scaffold must have mechanical properties that closely match those of the target tissue. The achievement of both goals may be possible by careful control of the scaffold architecture. Recently, electrospinning has emerged as an attractive means to form fused fibre scaffolds for tissue engineering. The diameter and relative orientation of fibres affect cell behaviour, but their impact on the tensile properties of the scaffolds has not been rigorously characterized. To examine the structure-property relationship, electrospun meshes were made from a polyurethane elastomer with different fibre diameters and orientations and mechanically tested to determine the dependence of the elastic modulus on the mesh architecture. Concurrently, a multiscale modelling strategy developed for type I collagen networks was employed to predict the mechanical behaviour of the polyurethane meshes. Experimentally, the measured elastic modulus of the meshes varied from 0.56 to 3.0 MPa depending on fibre diameter and the degree of fibre alignment. Model predictions for tensile loading parallel to fibre orientation agreed well with experimental measurements for a wide range of conditions when a fitted fibre modulus of 18 MPa was used. Although the model predictions were less accurate in transverse loading of anisotropic samples, these results indicate that computational modelling can assist in design of electrospun artificial tissue scaffolds.

  19. Ganglion cell-inner plexiform layer and retinal nerve fibre layer changes within the macula in retinitis pigmentosa: a spectral domain optical coherence tomography study.

    Science.gov (United States)

    Yoon, Chang Ki; Yu, Hyeong Gon

    2018-03-01

    To investigate how macular ganglion cell-inner plexiform layer (GCIPL) and retinal nerve fibre layer (RNFL) thicknesses within the macula change with retinitis pigmentosa (RP) severity. Spectral domain optical coherence tomography (SD-OCT) was used to examine 177 patients with RP and 177 normal controls. An optical coherence tomography (OCT) line scan was used to grade RP severity. Retinitis pigmentosa (RP) was categorized as more advanced if there was no identifiable inner segment ellipsoid (ISe) band (NISE) and as less advanced if an ISe band could be identified and peripheral loss of ISe was apparent (IISE). Ganglion cell-inner plexiform layer (GCIPL) and RNFL thicknesses were manually measured on OCT images and analysed. Pearson's correlation analyses were used to examine correlations between GCIPL thickness, RNFL thickness, visual acuity (VA) and visual field extent in patients and controls. Ganglion cell-inner plexiform layer (GCIPL) was significantly thicker in IISE than in control eyes (p fibre layer (RNFL) was significantly thicker in eyes with IISE and NISE than in control eyes in both horizontal and vertical meridians (all p < 0.001). Ganglion cell-inner plexiform layer (GCIPL) thickness showed a weak positive correlation with vision, and RNFL thickness showed a weak negative correlation with vision and visual field extent. Based on these results, the inner retina, including the GCIPL and RNFL, maintains its gross integrity longer than the photoreceptor layer in RP. Additionally, thickening of the inner retina may have some functional implications in patients with RP. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  20. Contact lens in keratoconus

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2013-01-01

    Full Text Available Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP lenses, soft and soft toric lenses, piggy back contact lenses (PBCL, hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

  1. Contact lens in keratoconus

    Science.gov (United States)

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL. PMID:23925325

  2. Angiogenic effect induced by mineral fibres

    International Nuclear Information System (INIS)

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

    2011-01-01

    Highlights: → In this study we described the angiogenetic effect of some mineral fibres. → Wollastonite fibres induce blood vessel formation. → The size and shape of the fibres were important factors for the cell signalling. → Wollastonite induce ROS-NFκB activation and EGFR signalling. → Involvement of wollastonite exposure in the development of pathological conditions. -- Abstract: 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-κB (NFκB) 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 NFκB activation were involved in the cytokine and angiogenic factor release. However, only the EGFR activation was able to induce angiogenesis. The WFs

  3. HIPPI and Fibre Channel

    International Nuclear Information System (INIS)

    Tolmie, D.E.

    1992-01-01

    The High-Performance Parallel Interface (HIPPI) and Fibre Channel are near-gigabit per second data communications interfaces being developed in ANSI standards Task Group X3T9.3. HIPPI is the current interface of choice in the high-end and supercomputer arena, and Fibre Channel is a follow-on effort. HIPPI came from a local area network background, and Fibre Channel came from a mainframe to peripheral interface background

  4. Artificial skin--culturing of different skin cell lines for generating an artificial skin substitute on cross-weaved spider silk fibres.

    Directory of Open Access Journals (Sweden)

    Hanna Wendt

    Full Text Available BACKGROUND: In the field of Plastic Reconstructive Surgery the development of new innovative matrices for skin repair is in urgent need. The ideal biomaterial should promote attachment, proliferation and growth of cells. Additionally, it should degrade in an appropriate time period without releasing harmful substances, but not exert a pathological immune response. Spider dragline silk from Nephila spp meets these demands to a large extent. METHODOLOGY/PRINCIPAL FINDINGS: Native spider dragline silk, harvested directly out of Nephila spp spiders, was woven on steel frames. Constructs were sterilized and seeded with fibroblasts. After two weeks of cultivating single fibroblasts, keratinocytes were added to generate a bilayered skin model, consisting of dermis and epidermis equivalents. For the next three weeks, constructs in co-culture were lifted on an originally designed setup for air/liquid interface cultivation. After the culturing period, constructs were embedded in paraffin with an especially developed program for spidersilk to avoid supercontraction. Paraffin cross-sections were stained in Haematoxylin & Eosin (H&E for microscopic analyses. CONCLUSION/SIGNIFICANCE: Native spider dragline silk woven on steel frames provides a suitable matrix for 3 dimensional skin cell culturing. Both fibroblasts and keratinocytes cell lines adhere to the spider silk fibres and proliferate. Guided by the spider silk fibres, they sprout into the meshes and reach confluence in at most one week. A well-balanced, bilayered cocultivation in two continuously separated strata can be achieved by serum reduction, changing the medium conditions and the cultivation period at the air/liquid interphase. Therefore spider silk appears to be a promising biomaterial for the enhancement of skin regeneration.

  5. Effects of white light-emitting diode (LED) light exposure with different correlated color temperatures (CCTs) on human lens epithelial cells in culture.

    Science.gov (United States)

    Xie, Chen; Li, Xiuyi; Tong, Jianping; Gu, Yangshun; Shen, Ye

    2014-01-01

    Cataract is the major cause for legal blindness in the world. Oxidative stress on the lens epithelial cells (hLECs) is the most important factor in cataract formation. Cumulative light-exposure from widely used light-emitting diodes (LEDs) may pose a potential oxidative threat to the lens epithelium, due to the high-energy blue light component in the white-light emission from diodes. In the interest of perfecting biosafety standards for LED domestic lighting, this study analyzed the photobiological effect of white LED light with different correlated color temperatures (CCTs) on cultured hLECs. The hLECs were cultured and cumulatively exposed to multichromatic white LED light with CCTs of 2954, 5624, and 7378 K. Cell viability of hLECs was measured by Cell Counting Kit-8 (CCK-8) assay. DNA damage was determined by alkaline comet assay. Intracellular reactive oxygen species (ROS) generation, cell cycle, and apoptosis were quantified by flow cytometry. Compared with 2954 and 5624 K LED light, LED light having a CCT of 7378 K caused overproduction of intracellular ROS and severe DNA damage, which triggered G2 /M arrest and apoptosis. These results indicate that white LEDs with a high CCT could cause significant photobiological damage to hLECs. © 2014 The American Society of Photobiology.

  6. Hemp fibres: Enzymatic effect of microbial processing on fibre bundle structure

    DEFF Research Database (Denmark)

    Thygesen, Anders; Liu, Ming; Meyer, Anne S.

    2013-01-01

    The effects of microbial pretreatment on hemp fibres were evaluated after microbial retting using the white rot fungi Ceriporiopsis subvermispora and Phlebia radiata Cel 26 and water retting. Based on chemical composition, P. radiata Cel 26 showed the highest selectivity for pectin and lignin...... degradation and lowest cellulose loss (14%) resulting in the highest cellulose content (78.4%) for the treated hemp fibres. The pectin and lignin removal after treatment with P. radiata Cel 26 were of the order 82% and 50%, respectively. Aligned epoxy-matrix composites were made from hemp fibres defibrated...... hemp fibres were badly impregnated due to porosity caused by surface impurities such as epidermis and other pectin rich plant cells. The pectin and lignin mainly located in the outer part of the fibres were assumed to be extracted and degraded by pectinase and peroxidase enzymes produced by the fungi....

  7. In vivo study of lens regeneration in Rana cyanophlyctis under ...

    African Journals Online (AJOL)

    SAM

    2014-03-12

    Mar 12, 2014 ... enhanced the percentage lens regeneration not only in young tadpoles but also in froglets. Lens regeneration ability ... Influence of vitamin A and ascorbic acid on lens regeneration in young, mature tadpoles and froglets of the frog Rana cyanophlyctis. Group .... ingested by macrophages. Dorsal iris cells ...

  8. Crystal structure of raptor adenovirus 1 fibre head and role of the beta-hairpin in siadenovirus fibre head domains.

    Science.gov (United States)

    Nguyen, Thanh H; Ballmann, Mónika Z; Do, Huyen T; Truong, Hai N; Benkő, Mária; Harrach, Balázs; van Raaij, Mark J

    2016-06-22

    Most adenoviruses recognize their host cells via an interaction of their fibre head domains with a primary receptor. The structural framework of adenovirus fibre heads is conserved between the different adenovirus genera for which crystal structures have been determined (Mastadenovirus, Aviadenovirus, Atadenovirus and Siadenovirus), but genus-specific differences have also been observed. The only known siadenovirus fibre head structure, that of turkey adenovirus 3 (TAdV-3), revealed a twisted beta-sandwich resembling the reovirus fibre head architecture more than that of other adenovirus fibre heads, plus a unique beta-hairpin embracing a neighbouring monomer. The TAdV-3 fibre head was shown to bind sialyllactose. Raptor adenovirus 1 (RAdV-1) fibre head was expressed, crystallized and its structure was solved and refined at 1.5 Å resolution. The structure could be solved by molecular replacement using the TAdV-3 fibre head structure as a search model, despite them sharing a sequence identity of only 19 %. Versions of both the RAdV-1 and TAdV-3 fibre heads with their beta-hairpin arm deleted were prepared and their stabilities were compared with the non-mutated proteins by a thermal unfolding assay. The structure of the RAdV-1 fibre head contains the same twisted ABCJ-GHID beta-sandwich and beta-hairpin arm as the TAdV-3 fibre head. However, while the predicted electro-potential surface charge of the TAdV-3 fibre head is mainly positive, the RAdV-1 fibre head shows positively and negatively charged patches and does not appear to bind sialyllactose. Deletion of the beta-hairpin arm does not affect the structure of the raptor adenovirus 1 fibre head and only affects the stability of the RAdV-1 and TAdV-3 fibre heads slightly. The high-resolution structure of RAdV-1 fibre head is the second known structure of a siadenovirus fibre head domain. The structure shows that the siadenovirus fibre head structure is conserved, but differences in the predicted surface charge

  9. Fibre-concrete container

    International Nuclear Information System (INIS)

    2000-01-01

    In this leaflet the fibre-concrete container for radioactive wastes is described. The fibre container is made of fibre-concrete that contains cement, aggregate, sand, filter, flame-silica, super-plastificator, water and scattered metal fibres. The fibre-concrete container has a dice shape with outer dimension 1.7 x 1.7 x 1.7 m. It is mounted of a container body, a container cover and two caps. Total weight of container is 4,240 kg, maximum weight of loaded container do not must exceed 15,000 kg. The physical and mechanical properties of the fibre-concrete container are described in detail. The fibre-concrete container manufactured for storing of low and intermediate radioactive wastes. A fibre-concrete container utilization to store of radioactive wastes solves these problems: increase of stability of stored packages of radioactive waste; watertightness within 300 years at least; static stability of bearing space; better utilization of bearing spaces; insulation of radioactive waste in a case of seismic and geological event; increase of fire resistance; and transport of radioactive waste

  10. Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Sanchez Bjarklev, Araceli

    Photonic crystal fibres represent one of the most active research areas today in the field of optics. The diversity of applications that may be addressed by these fibres and their fundamental appeal, by opening up the possibility of guiding light in a radically new way compared to conventional...... optical fibres, have spun an interest from almost all areas of optics and photonics. The aim of this book is to provide an understanding of the different types of photonic crystal fibres and to outline some of the many new and exciting applications that these fibres offer. The book is intended for both...... readers with a general interest in photonic crystals, as well as for scientists who are entering the field and desire a broad overview as well as a solid starting point for further specialized stuides. Teh book, therefore, covers bothe general aspects such as the link from classical optics to photonic...

  11. FibreBags vs. FibreCaps for acid and neutral detergent fibre analysis

    OpenAIRE

    Koivisto , Jason

    2003-01-01

    International audience; A new procedure for determining acid detergent fibre and neutral detergent fibre (ADF and NDF) was developed to reduce the need for filtration and to allow for batch processing of forage samples. The FibreBag system is an economically necessary evolution of the earlier FibreCap system. The purpose of this enquiry was to determine if the FibreBag is a suitable replacement for the FibreCap. The FibreBag method produced very similar results to the FibreCap system of analy...

  12. The role of low light intensity: A step towards understanding the connection between light, optic/lens and photovoltaic behavior for Sb2S3 thin-film solar cells

    Science.gov (United States)

    Lojpur, Vesna; Mitrić, Miodrag; Validžić, Ivana Lj

    2018-05-01

    We report here an optic/lens system that we used so far, for cooling the surface of solar cells, the reduction of light intensity and the change of light distribution that reaches the surface of the solar cell. The objective was to improve photovoltaic characteristics under very low light illumination, as well as to understand the connection between light, optic/lens and photovoltaic behavior for Sb2S3 thin-film solar cells. It was found that for all so far designed thin-film solar cells made and based on the synthesized Sb2S3, optics/lens system causes an increase in open circuit voltage (VOC) and short circuit current (ISC) and thus the efficiencies of made solar devices. Values of energy gaps for the thin-films made devices were in the range from 1.4 to 2 eV. Improvements of the photovoltaic response of the designed devices are found to be better at the lower light intensity (5% sun), than at higher intensities of light. For the same intensity of light used optic/lens improves the efficiency of the devices, by changing the light distribution. Other processes that are related to the optics/lens system, leading to an increase in ISC and VOC and consequently to an increase in efficiencies of the designed devices, are investigated.

  13. Automated Fresnel lens tester system

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.S.

    1981-07-01

    An automated data collection system controlled by a desktop computer has been developed for testing Fresnel concentrators (lenses) intended for solar energy applications. The system maps the two-dimensional irradiance pattern (image) formed in a plane parallel to the lens, whereas the lens and detector assembly track the sun. A point detector silicon diode (0.5-mm-dia active area) measures the irradiance at each point of an operator-defined rectilinear grid of data positions. Comparison with a second detector measuring solar insolation levels results in solar concentration ratios over the image plane. Summation of image plane energies allows calculation of lens efficiencies for various solar cell sizes. Various graphical plots of concentration ratio data help to visualize energy distribution patterns.

  14. The protective effect of beta-casomorphin-7 via promoting Foxo1 activity and nuclear translocation in human lens epithelial cells.

    Science.gov (United States)

    Zhu, Lihua; Li, Jia; Dayang, Wu; Bing, Li

    2018-03-08

    To investigate the protective effect of beta-casomorphin-7 (β-CM-7) in oxidative stressed human lens epithelial cells (HLECs) and to explore the possible mechanism for oxidative stress in human lens epithelial cells induced by high glucose. We used HLECs to determine the effect of different concentrations of β-CM-7 on cell viability by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolimol/L bromide (MTT) assay. We used flow cytometry to determine the content of reactive oxygen species (ROS) induced by oxidative stress and a bioassay kit to determine the oxidant malondialdehyde (MDA) and antioxidant enzyme superoxide dismutase (SOD) levels. We used Western blotting and an immunofluorescence assay to determine the expression of Forkhead box o1 (Foxo1), SP1, and the related protein glutathione peroxidase (GSH -px) at the molecular biology level as well as their intracellular localization. The expression of Foxo1 and SP1 were weakly expressed when the glucose concentration was 40 mM/L, but were highly expressed when cells were pretreated with an appropriate concentration of β-CM-7. After pretreatment with β-CM-7, the cells treated with 40 mM/L glucose for 48 h showed Foxo1 was transferred to the nucleus, and the expression of SP1 was increased. The content of ROS and MDA in the HLECs that were pretreated with β-CM-7 were lower than in those that were not pretreated (p <0.05). Accordingly, SOD was elevated in the cells pretreated with β-CM-7. The relative expression of GSH-px increased with increases of Foxo1 and SP1. β-CM-7 protects HLECs from oxidative damage by upregulating the relative expression of Foxo1 and promoting Foxo1 nuclear translocation.

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, ... Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume Contacts May Contain Chemicals Harmful to Eyes ...

  16. Reliability of fibre Bragg gratings in polymer optical fibre

    OpenAIRE

    Dobb, H.; Carroll, K.; Kalli, K.; Komodromos, M.; Themistos, C.; Peng, G.D.; Argyros, A.; Large, M.C.J.; van Eijkelenborg, M.A.; Arresy, M.; Kukureka, S.

    2006-01-01

    In this paper we report on investigations of some of the factors that have a bearing on the reliability and repeatability of polymer fibre Bragg gratings. The main issues discussed are the fibre preform composition, the fibre drawing conditions and the thermal history of the fibre grating.

  17. Fibre-reinforced hydrogels for tissue engineering

    Science.gov (United States)

    Waters, Sarah; Byrne, Helen; Chen, Mike; Dias Castilho, Miguel; Kimpton, Laura; Please, Colin; Whiteley, Jonathan

    2017-11-01

    Tissue engineers aim to grow replacement tissues in vitro to replace those in the body that have been damaged through age, trauma or disease. One approach is to seed cells within a scaffold consisting of an interconnected 3D-printed lattice of polymer fibres, cast in a hydrogel, and subject the construct (cell-seeded scaffold) to an applied load in a bioreactor. A key question is to understand how this applied load is distributed throughout the construct to the mechanosensitive cells. To address this, we exploit the disparate length scales (small inter-fibre spacing compared with construct dimensions). The fibres are treated as a linear elastic material and the hydrogel as a poroelastic material. We employ homogenisation theory to derive equations governing the material properties of a periodic, elastic-poroelastic composite. To validate the mobel, model solutions are compared to experimental data describing the unconfined compression of the fibre-reinforced hydrogels. The model is used to derive the bulk mechanical properties of a cylindrical construct of the composite material for a range of fibre spacings, and the local mechanical environment experienced by cells embedded within the construct is determined. Funded by the European Union Seventh Framework Programme (FP7/2007-2013).

  18. POLARISATION PRESERVING OPTICAL FIBRE

    DEFF Research Database (Denmark)

    2000-01-01

    A micro-structured optical fibre having a cladding comprising a number of elements having a non-circular cross-section. Each element has at least one part extending outside a circle having the same cross-sectional area as the element. These extending parts are directed in the same direction....... This cladding structure provides polarisation preserving properties to the optical fibre. Optical fibres using this technology may have claddings with elements placed non-periodically as well as in a two-dimensional periodic lattice - such as cladding providing Photonic Band Gap (PBG) effects....

  19. Breakage and debonding of short brittle fibres among particulates in a metal matrix

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2004-01-01

    The competition of failure by fibre cracking or decohesion of the fibre-matrix interface is analysed for aluminium reinforced by aligned, short SiC fibres. An axisymmetric unit-cell model containing a number of differently shaped fibres or particulates is used here to represent failure by debonding...... or fracture of a relatively long discontinuous fibre among particulates that do not fail. A cohesive zone model that accounts for normal separation as well as tangential separation is used to represent debonding, while fibre fracture is represented by a critical value of the average tensile stress on a cross...

  20. The Analysis of Intracellular and Intercellular Calcium Signaling in Human Anterior Lens Capsule Epithelial Cells with Regard to Different Types and Stages of the Cataract.

    Directory of Open Access Journals (Sweden)

    Marko Gosak

    Full Text Available In this work we investigated how modifications of the Ca2+ homeostasis in anterior lens epithelial cells (LECs are associated with different types of cataract (cortical or nuclear and how the progression of the cataract (mild or moderate affects the Ca2+ signaling. We systematically analyzed different aspects of intra- and inter-cellular Ca2+ signaling in the human LECs, which are attached to surgically isolated lens capsule (LC, obtained during cataract surgery. We monitored the temporal and spatial changes in intracellular Ca2+ concentration after stimulation with acetylcholine by means of Fura-2 fluorescence captured with an inverted microscope. In our analysis we compared the features of Ca2+ signals in individual cells, synchronized activations, spatio-temporal grouping and the nature of intercellular communication between LECs. The latter was assessed by using the methodologies of the complex network theory. Our results point out that at the level of individual cells there are no significant differences when comparing the features of the signals with regard either to the type or the stage of the cataract. On the other hand, noticeable differences are observed at the multicellular level, despite inter-capsule variability. LCs associated with more developed cataracts were found to exhibit a slower collective response to stimulation, a less pronounced spatio-temporal clustering of LECs with similar signaling characteristics. The reconstructed intercellular networks were found to be sparser and more segregated than in LCs associated with mild cataracts. Moreover, we show that spontaneously active LECs often operate in localized groups with quite well aligned Ca2+ activity. The presence of spontaneous activity was also found to affect the stimulated Ca2+ responses of individual cells. Our findings indicate that the cataract progression entails the impairment of intercellular signaling thereby suggesting the functional importance of altered Ca2

  1. RNA Interference Targeting Snail Inhibits the Transforming Growth Factor β2-Induced Epithelial-Mesenchymal Transition in Human Lens Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Ping Li

    2013-01-01

    Full Text Available Epithelial-msenchymal transition (EMT contributes to posterior capsule opacification (PCO type of cataract. Transcription factors Snail is a key trigger of EMT activated by transforming growth factor β (TGFβ. This study was done to investigate the effect of Snail targeting siRNA on TGFβ2-induced EMT in human lens epithelial cells. TGFβ2 treatment of cultured human epithelial cell line (HLEB3 upregulated the expression of Snail and the EMT relevant molecules such as vimentin and α-SMA but downregulated the expression of keratin and E-cadherin. After the stimulation of TGFβ2, the HLEB3 cells became fibroblast-like in morphology, and the junctions of cell-cell disappeared. TGFβ2 treatment also enhanced migration ability of HLEB3 cells. TGFβ2-induced Snail expression and EMT were significantly inhibited by Snail siRNA. By analyzing the response characteristics of HLEB3 in TGFβ2-induced EMT model with/without Snail-specific siRNA, we concluded that Snail is an element in the EMT of HLEB3 cells induced by TGFβ2. Snail siRNA targeting can block the induced EMT and therefore has the potential to suppress the development of PCO.

  2. DETECTORS: scintillating fibres

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    In the continual search for improved detection techniques, new materials are continually proving profitable. A good example is scintillating plastic fibres - tiny transparent threads sometimes finer than a human hair which transmit light. The narrowness and flexibility of these fibres was a major breakthrough for endoscopy - non-invasive techniques for viewing the otherwise inaccessible in surgery or machine inspection. In a more sophisticated form, these fibres find ready application in communications technology, where the goal is to transmit information rather than electrical power, replacing conventional and unwieldy current-carrying wire conductors. In particle physics, fibres have long been used to take the tiny scintillations produced when high energy particles hit fluorescent materials and 'conduct' them to photosensitive detectors some distance away

  3. Fibre illumination system

    DEFF Research Database (Denmark)

    2012-01-01

    the proximal end of the collection optics into the first end of the input fibre, each collector element having a principal axis for the collection of light defining an optical axis of the collector element. The optical axes of the collector elements are arranged in a radially outward pointing multi......Source: EP2426402A The invention relates to a fibre illumination module and system for the collection and delivery of daylight for illumination purposes. The fibre illumination module comprises a plurality of collector elements, each collector element comprising an input fibre having a first end...... and a second end, and a collection optics, the collection optics being configured to receive light incident on a distal end of the collection optics, to transfer at least partially the incident light to a proximal end of the collection optics, and to couple at least partially the transferred light from...

  4. Fibres Optiques En Therapie Laser Au Contact Du Tissu

    Science.gov (United States)

    Lenz, P.; Sabben, G.; Lambert, R.; Berger, F.

    1984-03-01

    Les fibres en quartz, non protegees par un courant de gaz et placees au contact du tissu, peuvent etre utilisees pratiquement indefiniment grace a un "autonettoyage" et une "regenera-tion". Elles provoquent des lesions tissulaires semblables a celles obtenues avec les fibres conventionnelles.

  5. Chemical Composition, Fibre Fraction and Anti-Nutritional ...

    African Journals Online (AJOL)

    acer

    However, the toxic compounds seem to become of significance nutritionally only when the plant constitutes a high proportion of the diet. Hence, the effects of high protein forage could .... NDF=Neutral detergent fibre; ADF=Acid detergent fibre; Acid detergent lignin; ADIash=Acid detergent Insoluble ash;Cell.=Cellulose and.

  6. Water holding capacity and enzymatic modification of pressed potato fibres

    NARCIS (Netherlands)

    Ramasamy, U.

    2014-01-01

    Cell wall polysaccharides (CWPs) contribute to the water holding capacity (WHC) of fibre rich feeds, such as pressed potato fibres (PPF). However, the role of CWPs on the WHC of PPF was unidentified so far.

    PPF was characterized to be abundant in arabinogalactan (AG) linked

  7. Optical fibre microwire sensors

    OpenAIRE

    Brambilla, G.; Belal, Mohammad; Jung, Y.; Song, Z.; Xu, F.; Newson, T.P.; Richardson, D.J.

    2011-01-01

    This paper reviews sensing applications of optical fibre microwires and nanowires. In addition to the usual benefits of sensors based on optical fibres, these sensors are extremely compact and have fast response speeds. In this review sensors will be grouped in three categories according to their morphology: linear sensors, resonant sensors and tip sensors. While linear and resonant sensors mainly exploit the fraction of power propagating outside the microwire physical boundary, tip sensors t...

  8. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  9. Visual outcome and changes in corneal endothelial cell density following aphakic iris-fixated intraocular lens implantation in pediatric eyes with subluxated lenses.

    Science.gov (United States)

    Siddiqui, Sorath Noorani; Khan, Ayesha

    2013-01-01

    To evaluate the visual outcome and corneal endothelial cell density after Artisan aphakic intraocular lens (IOL) implantation (Ophtec, Groningen, the Netherlands) in pediatric eyes with subluxated lenses. Artisan aphakic IOLs were implanted in 18 eyes of 11 children with subluxated lenses. Idiopathic subluxations and ectopia lentis due to Marfan syndrome were included, whereas subluxations due to trauma or buphthalmos were excluded. Best-corrected visual acuity (BCVA) and endothelial cell density were monitored. Mean postoperative BCVA and endothelial cell density at last follow-up visit were calculated. The age of children at the time of Artisan aphakic IOL implantation ranged from 8 to 16 years (mean: 11.58 ± 2.9 years). Mean follow-up was 9.12 ± 4.30 months. Mean postoperative logarithm of the minimum angle of resolution BCVA was 0.26 ± 0.13 (P = .001) and mean postoperative endothelial cell density was 2,860 ± 435 cells/mm(2) (P = .000). Mean endothelial cell loss was 17.1%. Artisan aphakic IOL implantation is a safe surgical choice in the management of ectopia lentis in the pediatric age group. It has minimal complications and is less traumatic to pediatric eyes. However, long-term follow-up of these children is required.[J Pediatr Ophthalmol Strabismus 2013;50(3):178-182.]. Copyright 2013, SLACK Incorporated.

  10. Fibre Concrete 2017

    Science.gov (United States)

    2017-09-01

    9th international conference on fibre reinforced concretes (FRC), textile reinforced concretes (TRC) and ultra-high performance concretes (UHPC) Preface The Fibre Concrete Conference series is held biennially to provide a platform to share knowledge on fibre reinforced concretes, textile concretes and ultra-high performance concretes regarding material properties and behaviour, technology procedures, topics of long-term behaviour, creep, durability; sustainable aspects of concrete including utilisation of waste materials in concrete production and recycling of concrete. The tradition of Fibre Concrete Conferences started in eighties of the last century. Nowadays the conference is organized by the Department of Concrete and Masonry Structures of the Czech Technical University in Prague, Faculty of Civil Engineering. The 9th International Conference Fibre Concrete 2017 had 109 participants from 27 countries all over the world. 55 papers were presented including keynote lectures of Professor Bažant, Professor Bartoš and Dr. Broukalová. The conference program covered wide range of topics from scientific research to practical applications. The presented contributions related to performance and behaviour of cement based composites, their long-term behaviour and durability, sustainable aspects, advanced analyses of structures from these composites and successful applications. This conference was organized also to honour Professor Zděnek P. Bažant on the occasion of his jubilee and to appreciate his merits and discoveries in the field of fibre reinforced composites, structural mechanics and engineering.

  11. Crystalline lens radioprotectors

    International Nuclear Information System (INIS)

    Belkacemi, Y.; Pasquier, D.; Castelain, B.; Lartigau, E.; Warnet, J.M.

    2003-01-01

    During more than a half of century, numerous compounds have been tested in different models against radiation-induced cataract. In this report, we will review the radioprotectors that have been already tested for non-human crystalline lens protection. We will focus on the most important published studies in this topic and the mechanisms of cyto-protection reported in. vitro and in. vivo from animals. The most frequent mechanisms incriminated in the cyto-protective effect are: free radical scavenging, limitation of lipid peroxidation, modulation of cycle progression increase of intracellular reduced glutathione pool, reduction of DNA strand breaks and limitation of apoptotic cell death. Arnifostine (or Ethyol) and anethole dithiolethione (or Sulfarlem), already used clinically as chemo- and radio-protectants, could be further test?r for ocular radioprotection particularly for radiation-induced cataract. (author)

  12. Debonding of short fibres among particulates in a metal matrix composite

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2003-01-01

    A numerical analysis is carried out for the development of damage by fibre-matrix debonding in aluminium reinforced by aligned, short SiC fibres. A unit cell-model that has earlier been applied to study materials with arrays of transversely staggered fibres is here extended to contain a number...

  13. Polyol pathway-dependent osmotic and oxidative stresses in aldose reductase-mediated apoptosis in human lens epithelial cells: role of AOP2.

    Science.gov (United States)

    Kubo, E; Urakami, T; Fatma, N; Akagi, Y; Singh, Dhirendra P

    2004-02-20

    Aldose reductase (AR) has been implicated as a major contributor to the pathogenesis of diabetic cataracts. AR activation generates osmotic and oxidative stresses via the polyol pathway and induces cell death signals. Antioxidant protein 2 (AOP2) protects cells from oxidative stress. We investigated the effect of AR overexpression on polyol accumulation and on hyperglycemic oxidative stress and osmotic stress, as well as the effects of these stresses on human lens epithelial cell (hLEC) survival. hLECs overexpressing the AR became apoptotic during hyperglycemia and showed elevated levels of intracellular polyols. Glutathione and AOP2 levels were significantly decreased in these cells. Interestingly, supply of AOP2 and/or the AR inhibitor fidarestat protected the cells against hyperglycemia-induced death. Overexpression of AR increased osmotic and oxidative stresses, resulting in increased apoptosis in hLECs. Because AOP2 protects hyperglycemia-induced hLEC apoptosis, this molecule may have the potential to prevent hyperglycemia-mediated complications in diabetes.

  14. Uncoupling of attenuated myo-[3H]inositol uptake and dysfunction in Na(+)-K(+)-ATPase pumping activity in hypergalactosemic cultured bovine lens epithelial cells

    International Nuclear Information System (INIS)

    Cammarata, P.R.; Tse, D.; Yorio, T.

    1991-01-01

    Attenuation of both the active transport of myo-inositol and Na(+)-K(+)-ATPase pumping activity has been implicated in the onset of sugar cataract and other diabetic complications in cell culture and animal models of the disease. Cultured bovine lens epithelial cells (BLECs) maintained in galactose-free Eagle's minimal essential medium (MEM) or 40 mM galactose with and without sorbinil for up to 5 days were examined to determine the temporal effects of hypergalactosemia on Na(+)-K(+)-ATPase and myo-inositol uptake. The Na(+)-K(+)-ATPase pumping activity after 5 days of continuous exposure to galactose did not change, as demonstrated by 86Rb uptake. The uptake of myo-[3H]inositol was lowered after 20 h of incubation in galactose and remained below that of the control throughout the 5-day exposure period. The coadministration of sorbinil to the galactose medium normalized the myo-[3H]inositol uptake. No significant difference in the rates of passive efflux of myo-[3H]inositol or 86Rb from preloaded galactose-treated and control cultures was observed. Culture-media reversal studies were also carried out to determine whether the galactose-induced dysfunction in myo-inositol uptake could be corrected. BLECs were incubated in galactose for 5 days, then changed to galactose-free physiological medium with and without sorbinil for a 1-day recovery period. myo-Inositol uptake was reduced to 34% of control after 6 days of continuous exposure to galactose. Within 24 h of media reversal, myo-inositol uptake returned to or exceeded control values in BLECs switched to either MEM or MEM with sorbinil.2+ reversible and occurred independently of changes in Na(+)-K(+)-ATPase pumping activity in cultured lens epithelium, indicating that the two parameters are not strictly associated and that the deficit in myo-inositol uptake occurs rapidly during hypergalactosemia

  15. Uncoupling of attenuated myo-(3H)inositol uptake and dysfunction in Na(+)-K(+)-ATPase pumping activity in hypergalactosemic cultured bovine lens epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Cammarata, P.R.; Tse, D.; Yorio, T. (Department of Anatomy, Texas College of Osteopathic Medicine/University of North Texas, Fort Worth (USA))

    1991-06-01

    Attenuation of both the active transport of myo-inositol and Na(+)-K(+)-ATPase pumping activity has been implicated in the onset of sugar cataract and other diabetic complications in cell culture and animal models of the disease. Cultured bovine lens epithelial cells (BLECs) maintained in galactose-free Eagle's minimal essential medium (MEM) or 40 mM galactose with and without sorbinil for up to 5 days were examined to determine the temporal effects of hypergalactosemia on Na(+)-K(+)-ATPase and myo-inositol uptake. The Na(+)-K(+)-ATPase pumping activity after 5 days of continuous exposure to galactose did not change, as demonstrated by 86Rb uptake. The uptake of myo-(3H)inositol was lowered after 20 h of incubation in galactose and remained below that of the control throughout the 5-day exposure period. The coadministration of sorbinil to the galactose medium normalized the myo-(3H)inositol uptake. No significant difference in the rates of passive efflux of myo-(3H)inositol or 86Rb from preloaded galactose-treated and control cultures was observed. Culture-media reversal studies were also carried out to determine whether the galactose-induced dysfunction in myo-inositol uptake could be corrected. BLECs were incubated in galactose for 5 days, then changed to galactose-free physiological medium with and without sorbinil for a 1-day recovery period. myo-Inositol uptake was reduced to 34% of control after 6 days of continuous exposure to galactose. Within 24 h of media reversal, myo-inositol uptake returned to or exceeded control values in BLECs switched to either MEM or MEM with sorbinil.2+ reversible and occurred independently of changes in Na(+)-K(+)-ATPase pumping activity in cultured lens epithelium, indicating that the two parameters are not strictly associated and that the deficit in myo-inositol uptake occurs rapidly during hypergalactosemia.

  16. Macular Ganglion Cell Layer and Peripapillary Retinal Nerve Fibre Layer Thickness in Patients with Unilateral Posterior Cerebral Artery Ischaemic Lesion: An Optical Coherence Tomography Study.

    Science.gov (United States)

    Anjos, Rita; Vieira, Luisa; Costa, Livio; Vicente, André; Santos, Arnaldo; Alves, Nuno; Amado, Duarte; Ferreira, Joana; Cunha, João Paulo

    2016-02-01

    The purpose of this study is to evaluate the macular ganglion cell layer (GCL) and peripapillary retinal nerve fibre layer (RNFL) thickness in patients with unilateral posterior cerebral artery (PCA) ischaemic lesions using spectral-domain optical coherence tomography (SD-OCT). A prospective, case-control study of patients with unilateral PCA lesion was conducted in the neuro-ophthalmology clinic of Centro Hospitalar Lisboa Central. Macular and peripapillary SD-OCT scans were performed in both eyes of each patient. Twelve patients with PCA lesions (stroke group) and 12 healthy normal controls were included in this study. Peripapillary RNFL comparison between both eyes of the same subject in the stroke group found a thinning in the superior-temporal ( p = 0.008) and inferior-temporal ( p = 0.023) sectors of the ipsilateral eye and nasal sector ( p = 0.003) of the contralateral eye. Macular GCL thickness comparison showed a reduction temporally in the ipsilateral eye ( p = 0.004) and nasally in the contralateral eye ( p = 0.002). Peripapillary RNFL thickness was significantly reduced in both eyes of patients with PCA compared with controls, affecting all sectors in the contralateral eye and predominantly temporal sectors in the ipsilateral eye. A statistically significant decrease in macular GCL thickness was found in both hemiretinas of both eyes of stroke patients when compared with controls ( p < 0.05). This study shows that TRD may play a role in the physiopathology of lesions of the posterior visual pathway.

  17. Evaluation of retinal nerve fibre layer, ganglion cell layer and choroidal thickness with optical coherence tomography in migraine patients: a case-control study.

    Science.gov (United States)

    Gunes, Aygül; Karadag, Ayse Sevgi; Yazgan, Serpil; Celik, Haci Ugur; Simsek, Ali

    2018-01-01

    Evaluation of retinal nerve fibre layer (RNFL), ganglion cell layer (GCL) and choroidal thickness (CT) with optical coherence tomography (OCT) in chronic migraine patients, to compare with healthy controls. Ninety-four eyes of 47 chronic migraine patients (Group 1) and 68 eyes of 34 healthy individuals (Group 2) were included in this prospective case-control study. The right and left eyes were separately evaluated. Mean peripapillary RNFL thicknesses, mean GCL measured from superior and inferior quadrants, and mean CT were measured at three different regions (central, 500 μm nasal and temporal region of the fovea). There was no statistically significant differences in RNFL between the two groups (p > 0.05), while CT values were significantly higher and GCL values were significantly lower in chronic migraine groups (p 0.05). In this study, we observed chronic migraine disease does not have any effect on peripapillary RNFL thickness; however, increases in CT and decreases in GCL thickness were observed in migraine patients. © 2017 Optometry Australia.

  18. Intrusive growth of primary and secondary phloem fibres in hemp stem determines fibre-bundle formation and structure

    Science.gov (United States)

    Snegireva, Anastasia; Chernova, Tatyana; Ageeva, Marina; Lev-Yadun, Simcha; Gorshkova, Tatyana

    2015-01-01

    Plant fibres—cells with important mechanical functions and a widely used raw material—are usually identified in microscopic sections only after reaching a significant length or after developing a thickened cell wall. We characterized the early developmental stages of hemp (Cannabis sativa) stem phloem fibres, both primary (originating from the procambium) and secondary (originating in the cambium), when they still had only a primary cell wall. We gave a major emphasis to the role of intrusive elongation, the specific type of plant cell growth by which fibres commonly attain large cell length. We could identify primary phloem fibres at a distance of only 1.2–1.5 mm from the shoot apical meristem when they grew symplastically with the surrounding tissues. Half a millimeter further downwards along the stem, fibres began their intrusive elongation, which led to a sharp increase in fibre numbers visible within the stem cross-sections. The intrusive elongation of primary phloem fibres was completed within the several distal centimetres of the growing stem, before the onset of their secondary cell wall formation. The formation of secondary phloem fibres started long after the beginning of secondary xylem formation. Our data indicate that only a small portion of the fusiform cambial initials (hemp, but may be applied to many other species. PMID:26019229

  19. REFRACTIVE NEUTRON LENS

    OpenAIRE

    Petrov, P. V.; Kolchevsky, N. N.

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  20. Contact lens in keratoconus

    OpenAIRE

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the En...

  1. Role of Aquaporin 0 in lens biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  2. Glass ceramic fibres

    International Nuclear Information System (INIS)

    Blaschek, O.; Paulitsch, P.

    1983-01-01

    As the correlation between mineralogical phase and chemical composition influences the type of application at different high temperatures, we studied the mineralogical phases of nine crystal glass fibres of the temperature ranges 1 150 degrees Celsius (Type 1), 1 400 degrees Celsius (Type 2) and 1 500 degrees Celsius (Type 3) at various high temperatures. The methods used in the study were microscopy, X-ray diffraction, transmission electron microscopy and differential thermal analysis. The investigations showed that mullite forms in glassy fibres of the system Al 2 O 3 . SiO 2 from 850 degrees Celsius to 990 degrees Celsius as 2/1 mullite; 3/2 mullite appeared above 990 degrees Celsius besides the crystallization of cristobalite. Fibres with 95 per cent Al 2 O 3 include the phases delta-Al 2 O 3 and alpha- Al 2 O 3 and mullite. Delta- Al 2 O 3 is stable up to 1 100 degrees Celsius. Alpha-Al 2 O 3 and mullite are only stable phases at 1 400 degrees Celsius. These different crystal phases influence the quality of the technical fibre according to the stability field of glass and crystals. This study has determined that it is possible to identify different fibres from different productions by their mineralogical compositions and to relate them to the high temperature application

  3. Tissue elasticity and the ageing elastic fibre.

    Science.gov (United States)

    Sherratt, Michael J

    2009-12-01

    The ability of elastic tissues to deform under physiological forces and to subsequently release stored energy to drive passive recoil is vital to the function of many dynamic tissues. Within vertebrates, elastic fibres allow arteries and lungs to expand and contract, thus controlling variations in blood pressure and returning the pulmonary system to a resting state. Elastic fibres are composite structures composed of a cross-linked elastin core and an outer layer of fibrillin microfibrils. These two components perform distinct roles; elastin stores energy and drives passive recoil, whilst fibrillin microfibrils direct elastogenesis, mediate cell signalling, maintain tissue homeostasis via TGFβ sequestration and potentially act to reinforce the elastic fibre. In many tissues reduced elasticity, as a result of compromised elastic fibre function, becomes increasingly prevalent with age and contributes significantly to the burden of human morbidity and mortality. This review considers how the unique molecular structure, tissue distribution and longevity of elastic fibres pre-disposes these abundant extracellular matrix structures to the accumulation of damage in ageing dermal, pulmonary and vascular tissues. As compromised elasticity is a common feature of ageing dynamic tissues, the development of strategies to prevent, limit or reverse this loss of function will play a key role in reducing age-related morbidity and mortality.

  4. Differences in mean fibre diameter and fibre diameter variance in ...

    African Journals Online (AJOL)

    sampled at five different body locations (Figure 1) at an age of 15 months. Samples were analysed by the Wool Testing. Bureaux, using an Optical Fibre Diameter Analyser which measured 4000 individual fibres in each sample. Apart from the mean, the variance of fibre diameter within samples was available. The statistical ...

  5. Multibeam Fibre Laser Cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    -laser cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single......The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre...

  6. Polarisation effects in fibre lasers

    OpenAIRE

    Lin, J.T.; Morkel, P.R.; Reekie, L.; Payne, D.N.

    1987-01-01

    Two orthogonal polarisation eigenmodes have been observed in a single-mode fibre laser. Experimental investigation shows good agreement with theoretical analysis. Both Nd3+ and Er3+-doped single-polarisation single-mode fibre lasers have been demonstrated

  7. Modelling of photonic crystal fibres

    DEFF Research Database (Denmark)

    Knudsen, Erik

    2003-01-01

    , as well as a honeycomb bandgap fibre and the first analysis of semi-periodic layered air-hole fibres. Using the modelling framework established as a basis, we provide an analysis of microbend loss, by regarding displacement of a fibre core as a stationary stochastic process, inducing mismatch between......In the presenta ph.d. work a theoretical study of aspects of modelling photonic crystal fibres was carried out. Photonic crystal fibres form a class of optical waveguides where guidance is no longer provided by a difference in refractive index between core and cladding. Instead, guidance...... is provided by an arrangement of air-holes running along the length of the fibre. Depending on the geometry of the fibre, the guiding mechanism may be either arising from the formation of a photonic bandgap in the cladding structure (photonic bandgap fibre), or by an effect resembling total internal...

  8. Current status of natural fibres

    CSIR Research Space (South Africa)

    Anandjiwala, RD

    2006-12-01

    Full Text Available Natural fibres and their products were prevalent since the early civilization of our society. Since then, the utilization and economic impact of natural fibre cultivation and down stream processing and products have been well established all over...

  9. Mineral fibres and health

    International Nuclear Information System (INIS)

    Hoskins, J.A.

    2001-01-01

    The use of inorganic fibrous materials is a comparatively new phenomenon and was uncommon before the Industrial Revolution. Humans evolved in a comparatively fibre-free environment and consequently never fully developed the defence mechanisms needed to deal with the consequences of inhaling fibres. However, the urban environment now has an airborne fibre concentration of around 1 f.l -1 , which is a tenfold increase on the natural background. Any sample of ambient air collected indoors or outdoors will probably contain some mineral fibres, but there is little evidence that these pose any risk to human health. They come from asbestos used in brakes, glass and mineral wools used as insulation and fire proofing of buildings, gypsum from plaster and a variety of types from many sources. Few of these have the potential to do any harm. Asbestos is the only fibre of note but urban levels are insignificant compared to occupational exposures. When the health of cohorts occupationally exposed to the several types of asbestos is studied the problem can be put into perspective. Studies of workers in the chrysotile industry exposed to much higher dust levels than in a factory today show no excess lung cancer or mesothelioma. By comparison those living near crocidolite mines, let alone working in them, may develop asbestos-related disease. As always, dose is the critical factor. Chrysotile is cleared from the lungs very efficiently, only the amphiboles are well retained. The only real health problem comes from the earlier use of asbestos products that may now be old, friable and damaged and made from amphibole or mixed fibre. If though, these are still in good condition, they do not pose a health problem. Asbestos-related diseases are very rare in those not occupationally exposed. Where they exist exposure has nearly always been to crocidolite. (author)

  10. Concrete workability and fibre content

    OpenAIRE

    Vikan, Hedda

    2007-01-01

    Research report Parameters influencing the workability of fibre concrete and maximum fibre content are given in this state of the art report along with the range of fibre types available on today’s market. The study reveales that new placing techniques and production methods are crucial in order to increase fibre content and concrete strength. Achieving the same mechanical properties as traditionally reinforced concrete will probably also demand changes of the matrix. Finally, reco...

  11. Ultraviolet B Radiation Stimulates the Interaction between Nuclear Factor of Activated T Cells 5 (NFAT5) and Nuclear Factor-Kappa B (NF-κB) in Human Lens Epithelial Cells.

    Science.gov (United States)

    Chung, Inyoung; Hah, Young-Sool; Ju, SunMi; Kim, Ji-Hye; Yoo, Woong-Sun; Cho, Hee-Young; Yoo, Ji-Myong; Seo, Seong-Wook; Choi, Wan-Sung; Kim, Seong-Jae

    2017-07-01

    Nuclear factor-kappa B (NF-κB) has been proposed as a therapeutic target for the treatment of cataracts. The authors investigated the relationship between nuclear factor of activated T cells 5 (NFAT5) and NF-κB in ultraviolet B (UVB)-irradiated human lens epithelial (HLE) cells. Human lens epithelial B-3 (HLE-B3) cells were exposed to UVB light at a dose of 10 mJ/cm 2 and then incubated for 24 h. Cell viability was assessed by using the Cell Counting Kit-8 (CCK-8) assay. Gene expression level of NFAT5 was determined using real-time quantitative polymerase chain reaction (qPCR). Protein expression levels of NFAT5, NF-κB p65, and α-smooth muscle actin (α-SMA) and the association of NFAT5 with the NF-κB p65 subunit were measured by Western blot analysis and a co-immunoprecipitation assay, respectively. The cellular distribution of NFAT5 and NF-κB p65 was examined by triple immunofluorescence staining. At 24 h after UVB exposure, cell viability significantly decreased in a dose-dependent manner, and UVB light (15 and 20 mJ/cm 2 ) significantly increased the ROS generation. UVB irradiation increased NFAT5 mRNA and protein levels and increased phosphorylation of NF-κB in HLE-B3 cells. α-SMA protein levels were increased in the irradiated cells. In addition, NFAT5 and NF-κB translocated from the cytoplasm to the nucleus, and binding between the p65 subunit and NFAT5 was increased. Exposure to UVB radiation induces nuclear translocation and stimulates binding between NFAT5 and NF-κB proteins in HLE-B3 cells. These interactions may form part of the biochemical mechanism of cataractogenesis in UVB-irradiated HLECs.

  12. Single-mode optical fibres

    CERN Document Server

    Cancellieri, G

    1991-01-01

    This book describes signal propagation in single-mode optical fibres for telecommunication applications. Such description is based on the analysis of field propagation, considering waveguide properties and also some of the particular characteristics of the material fibre. The book covers such recent advances as, coherent transmissions; optical amplification; MIR fibres; polarization maintaining; polarization diversity and photon counting.

  13. Natural fibres-based polymers

    Indian Academy of Sciences (India)

    Natural fibres-based polymers: Part I—Mechanical analysis of Pine needles reinforced biocomposites. Vijay Kumar Thakur A S ... Keeping in view the various advantages of natural fibres, in current series of green composites a study on natural fibre reinforced polymer composites has been made. This paper presents the ...

  14. Glaucomatous progression in the retinal nerve fibre and retinal ganglion cell-inner plexiform layers determined using optical coherence tomography-guided progression analysis.

    Science.gov (United States)

    Hwang, Young Hoon; Kim, Yeji; Chung, Jae Keun; Lee, Kwan Bok

    2018-02-01

    To investigate the characteristics of glaucomatous progression in circumpapillary retinal nerve fibre layer (RNFL) and macular retinal ganglion cell-inner plexiform layer (GCIPL) determined using optical coherence tomography-guided progression analysis (OCT-GPA). Serial OCT images of 527 glaucomatous eyes with greater than four OCT tests were screened. Among them, 106 (20.1 per cent) eyes with progression in either RNFL or GCIPL determined using OCT-GPA were included. Based on the agreement of progression detection between RNFL and GCIPL, the eyes were classified into the 'RNFL progression earlier group', 'GCIPL progression earlier group', or 'simultaneous progression group'. The type of progression was classified as diffuse, localised or mixed. Among the 106 eyes with progression, 100 (94.3 per cent) showed RNFL progression and 83 (78.3 per cent) showed GCIPL progression. Fifty-four (50.9 per cent), 13 (12.3 per cent), and 39 (36.8 per cent) eyes were classified into the RNFL progression earlier group, GCIPL progression earlier group, and simultaneous progression group, respectively. Diffuse-type progression was found in three (three per cent) eyes with RNFL progression and 32 (38.6 per cent) eyes with GCIPL progression. The most common location of progression was the 7 o'clock sector (42.0 per cent) in the RNFL and the inferotemporal sector (39.8 per cent) in the GCIPL. The most common characteristic of RNFL and GCIPL progression determined using OCT-GPA was localised thinning in the inferotemporal area. Progression was more frequently found in the RNFL than in the GCIPL, and diffuse-type progression was more frequent in the GCIPL than in the RNFL. © 2018 Optometry Australia.

  15. Evaluation of cell binding peptide (p15) with silk fibre enhanced hydroxyappatite bone substitute for posterolateral spinal fusion in sheep

    DEFF Research Database (Denmark)

    Axelsen, M.; Jespersen, Stig; Overgaard, Søren

    2015-01-01

    's gold standard are highly desired. Uninstrumented posterolateral fusion (PLF) is one of the most challenging bone graft procedures because of large graft size and lack of external stability. P15 is a synthetic 15 amino acid peptide sequence, identical to the biding site for alpha2-beta1 integrin...... on the surface of bone forming cells. The binding initiates natural intra- and extracellular signalling pathways, inducing production of growth factors, bone morphogenic proteins and cytokines. P15 peptide has previously shown to improve osteoinductive properties when coated on graft materials. Purpose...

  16. Microstructure, quantification and control of dislocations in bast-type plant fibres

    DEFF Research Database (Denmark)

    Madsen, Bo; Lester, Catherine L.; Mortensen, Ulrich Andreas

    2016-01-01

    analysis is presented for the quantification of dislocations in plant fibres. The protocol is evaluated with respect to its robustness, and the uncertainty of the determined content of dislocations. Based on in-situ straining of fibres under the optical microscopy, findings are presented to show......Bast-type plant fibres are increasingly being used for structural composite applications where high quality fibres with good mechanical properties are required. A central aspect for this application is the existence of dislocations in the cell wall of plant fibres, i.e. regions of misaligned...... that this leads to a reduction in the content of dislocations. This is indicating that dislocations in the cell wall of plant fibres are changeable structures. Preliminary work is presented where plant fibres are exposed to physical treatments involving moisture and mechanical straining in order to change...

  17. Airborne asbestos fibres monitoring in tunnel excavation.

    Science.gov (United States)

    Gaggero, Laura; Sanguineti, Elisa; Yus González, Adrián; Militello, Gaia Maria; Scuderi, Alberto; Parisi, Giovanni

    2017-07-01

    Tunnelling across ophiolitic formation with Naturally Occurring Asbestos (NOA) can release fibres into the environment, exposing workers, and the population, if fibres spread outside the tunnel, leading to increased risk of developing asbestos-related disease. Therefore, a careful plan of environmental monitoring is carried out during Terzo Valico tunnel excavation. In the present study, data of 1571 samples of airborne dust, collected between 2014 and 2016 inside the tunnels, and analyzed by SEM-EDS for quantification of workers exposure, are discussed. In particular, the engineering and monitoring management of 100 m tunnelling excavation across a serpentinite lens (Cravasco adit), intercalated within calcschists, is reported. At this chrysotile occurrence, 84% of 128 analyzed samples (from the zone closer to the front rock) were above 2 ff/l. However, thanks to safety measures implemented and tunnel compartmentation in zones, the asbestos fibre concentration did not exceed the Italian standard of occupational exposure (100 ff/l) and 100% of samples collected in the outdoor square were below 1 ff/l. During excavation under normal working conditions, asbestos concentrations were below 2 ff/l in 97.4% of the 668 analyzed samples. Our results showed that air monitoring can objectively confirm the presence of asbestos minerals at a rock front in relative short time and provide information about the nature of the lithology at the front. The present dataset, the engineering measures described and the operative conclusions are liable to support the improvement of legislation on workers exposure to asbestos referred to the tunnelling sector, lacking at present. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Intrinsic lens potential of neural retina inhibited by Notch signaling as the cause of lens transdifferentiation.

    Science.gov (United States)

    Iida, Hideaki; Ishii, Yasuo; Kondoh, Hisato

    2017-01-15

    Embryonic neural retinas of avians produce lenses under spreading culture conditions. This phenomenon has been regarded as a paradigm of transdifferentiation due to the overt change in cell type. Here we elucidated the underlying mechanisms. Retina-to-lens transdifferentiation occurs in spreading cultures, suggesting that it is triggered by altered cell-cell interactions. Thus, we tested the involvement of Notch signaling based on its role in retinal neurogenesis. Starting from E8 retina, a small number of crystallin-expressing lens cells began to develop after 20 days in control spreading cultures. By contrast, addition of Notch signal inhibitors to cultures after day 2 strongly promoted lens development beginning at day 11, and a 10-fold increase in δ-crystallin expression level. After Notch signal inhibition, transcription factor genes that regulate the early stage of eye development, Prox1 and Pitx3, were sequentially activated. These observations indicate that the lens differentiation potential is intrinsic to the neural retina, and this potential is repressed by Notch signaling during normal embryogenesis. Therefore, Notch suppression leads to lens transdifferentiation by disinhibiting the neural retina-intrinsic program of lens development. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. A comparative study of the apparent total tract digestibility of fibre in Icelandic and Danish Warmblood horses

    DEFF Research Database (Denmark)

    Jensen, Rasmus Bovbjerg; Brøkner, Christine; Knudsen, Knud Erik Bach

    2010-01-01

    and early or late cut haylage. Fibre was analyzed as crude fibre (CF), acid detergent fibre (ADF), neutral detergent fibre (NDF) and dietary fibre (DF: non-starch polysaccharides (NSP) plus lignin). In haylage all analyzed fibre fractions increased with advancing stage of maturity, with the cell wall......Four Icelandic (ICE) and four Danish Warmblood (DW) horses were used in a crossover study with two treatments to investigate the effect of breed and the effect of stage of maturity of haylage on the apparent total tract digestibility (ATTD) of a diet consisting of sugar beet pulp, black oats...

  20. Cell length variation in Phloem fibres within the bark of four tropical fruit trees Aegle Marmelos, Mangifera indica, Syzygium cumini, and Zizyphus mauritiana

    NARCIS (Netherlands)

    Ghouse, A.K.M.; Siddiqui, Firoz A.

    1976-01-01

    Bark samples from collections made at monthly intervals during the calendar years 1973 and 1974, were studied to estimate the average length of phloem fibres in different positions within the bark of four tropical fruit trees, viz. Aegle marmelos Correa, Mangifera indica L., Syzygium cumini L., and

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... new application of artificial intelligence shows whether a patient’s eyes point to high blood pressure or risk ...

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  4. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her ...

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... with Colored Contact Lenses Julian: Teenager Blinded In One Eye By Non-Prescription Contact Lens Laura: Vision ... Robyn: Blurry Vision and Daily Eye Drops After One Use Facts About Colored Contacts and Halloween Safety ...

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For ...

  8. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... in a pair of colored contact lenses, Laura Butler of Parkersburg, W.Va., had "extreme pain in ... to wear any kind of contact lens. In Butler's case, the lenses caused an infection and left ...

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... an impulsive buy from a souvenir shop, but 10 hours after she first put in a pair ... Prescription Contact Lens Laura: Vision Loss After Just 10 Hours Robyn: Blurry Vision and Daily Eye Drops ...

  11. bubble chamber lens

    CERN Multimedia

    Before the days of electronic detectors, visual techniques were used to detect particles, using detectors such as spark chambers and bubble chambers. This plexiglass lens was used to focus the image of tracks so they could be photographed.

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Contact Lens Facts Over-the-Counter Costume Contacts May Contain Chemicals Harmful to Eyes Four Ways Over- ... without a prescription are breaking the law, and may be fined $11,000 per violation. "Many of ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ...

  14. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... an ophthalmologist — an eye medical doctor — who will measure each eye and talk to you about proper ...

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. Follow the contact lens care directions for cleaning, disinfecting, and wearing the lenses. Never share contact ... with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American ...

  16. Viscous froth lens

    Science.gov (United States)

    Green, T. E.; Bramley, A.; Lue, L.; Grassia, P.

    2006-11-01

    Microscale models of foam structure traditionally incorporate a balance between bubble pressures and surface tension forces associated with curvature of bubble films. In particular, models for flowing foam microrheology have assumed this balance is maintained under the action of some externally imposed motion. Recently, however, a dynamic model for foam structure has been proposed, the viscous froth model, which balances the net effect of bubble pressures and surface tension to viscous dissipation forces: this permits the description of fast-flowing foam. This contribution examines the behavior of the viscous froth model when applied to a paradigm problem with a particularly simple geometry: namely, a two-dimensional bubble “lens.” The lens consists of a channel partly filled by a bubble (known as the “lens bubble”) which contacts one channel wall. An additional film (known as the “spanning film”) connects to this bubble spanning the distance from the opposite channel wall. This simple structure can be set in motion and deformed out of equilibrium by applying a pressure across the spanning film: a rich dynamical behavior results. Solutions for the lens structure steadily propagating along the channel can be computed by the viscous froth model. Perturbation solutions are obtained in the limit of a lens structure with weak applied pressures, while numerical solutions are available for higher pressures. These steadily propagating solutions suggest that small lenses move faster than large ones, while both small and large lens bubbles are quite resistant to deformation, at least for weak applied back pressures. As the applied back pressure grows, the structure with the small lens bubble remains relatively stiff, while that with the large lens bubble becomes much more compliant. However, with even further increases in the applied back pressure, a critical pressure appears to exist for which the steady-state structure loses stability and unsteady

  17. Expression of transcription factors Slug in the lens epithelial cells undergoing epithelial-mesenchymal transition induced by connective tissue growth factor

    Directory of Open Access Journals (Sweden)

    Ying-Na Wang

    2015-10-01

    Full Text Available AIM:To investigate the expression of transcription factors Slug in human lens epithelial cells (HLECs undergoing epithelial-mesenchymal transition (EMT induced by connective tissue growth factor (CTGF.METHODS: HLECs were treated with CTGF of different concentrations (20, 50 and 100 ng/mL or without CTGF (control for 24h. The morphological changes of HLECs were analysed by microscopy. The expression and cellular localization of Slug was evaluated by immumo-fluorescence. Expressions of Slug, E-cadherin and alpha smooth muscle actin (α-SMA were further determined by Western blot analysis. RESULTS: HLECs showed spidle fibrolasts-like characteristics and loosely connected each other after CTGF treatment. The immuno-fluorescence staining indicated that Slug was localized in the nuclei and its expression was induced by CTGF. The relative expressions of Slug protein were 1.64±0.11, 1.96 ±0.03, 3.12 ±0.10, and 4.08±0.14, respectively, in response to control group and treatment with CTGF of 20, 50 and 100 ng/mL (F=443.86, PCONCLUSION: Transcription factor Slug may be involved in EMT of HLECs induced by CTGF in vitro.

  18. Expression of transcription factors Slug in the lens epithelial cells undergoing epithelial-mesenchymal transition induced by connective tissue growth factor.

    Science.gov (United States)

    Wang, Ying-Na; Qin, Li; Li, Jing-Ming; Chen, Li; Pei, Cheng

    2015-01-01

    To investigate the expression of transcription factors Slug in human lens epithelial cells (HLECs) undergoing epithelial-mesenchymal transition (EMT) induced by connective tissue growth factor (CTGF). HLECs were treated with CTGF of different concentrations (20, 50 and 100 ng/mL) or without CTGF (control) for 24h. The morphological changes of HLECs were analysed by microscopy. The expression and cellular localization of Slug was evaluated by immumo-fluorescence. Expressions of Slug, E-cadherin and alpha smooth muscle actin (α-SMA) were further determined by Western blot analysis. HLECs showed spidle fibrolasts-like characteristics and loosely connected each other after CTGF treatment. The immuno-fluorescence staining indicated that Slug was localized in the nuclei and its expression was induced by CTGF. The relative expressions of Slug protein were 1.64±0.11, 1.96 ±0.03, 3.12 ±0.10, and 4.08±0.14, respectively, in response to control group and treatment with CTGF of 20, 50 and 100 ng/mL (F=443.86, PSlug protein levels were correlated well with up-expression of α-SMA (0.78±0.05, 0.85±0.06, 2.17±0.15, 2.86±0.10; F=449.85, PSlug may be involved in EMT of HLECs induced by CTGF in vitro.

  19. Optical Fibre Bundle

    CERN Multimedia

    These are sample fibre optic cables which are used for networking. Optical fibers are widely used in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data rates) than wire cables. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. This is useful for somewhere like CERN where magnets with their highly powerful magnetic fields could pose a problem.

  20. Fruiting branch K+ level affects cotton fibre elongation through osmoregulation

    Directory of Open Access Journals (Sweden)

    Jiashuo eYang

    2016-01-01

    Full Text Available Potassium (K deficiency in cotton plants results in reduced fibre length. As one of the primary osmotica, K+ contributes to an increase in cell turgor pressure during fibre elongation. Therefore, it is hypothesized that fibre length is affected by K deficiency through an osmotic pathway, so in 2012 and 2013, an experiment was conducted to test this hypothesis by imposing three potassium supply regimes (0, 125, 250 kg K ha-1 on a low-K-sensitive cultivar, Siza 3, and a low-K-tolerant cultivar, Simian 3. We found that fibres were longer in the later season bolls than in the earlier ones in cotton plants grown under normal growth conditions, but later season bolls showed a greater sensitivity to low-K stress, especially the low-K sensitive genotype. We also found that the maximum velocity of fibre elongation (Vmax is the parameter that best reflects the change in fibre elongation under K deficiency. This parameter mostly depends on cell turgor, so the content of the osmotically active solutes was analysed accordingly. Statistical analysis showed that K+ was the major osmotic factor affecting fibre length, and malate was likely facilitating K+ accumulation into fibres, which enabled the low-K-tolerant genotype to cope with low-K stress. Moreover, the low-K-tolerant genotype tended to have greater K+ absorptive capacities in the upper fruiting branches. Based on our findings, we suggest a fertilization scheme for Gossypium hirsutum that adds extra potash fertilizer or distributes it during the development of late season bolls to mitigate K deficiency in the second half of the growth season and to enhance fibre length in late season bolls.

  1. Effects of 1.8 GHz radiofrequency field on DNA damage and expression of heat shock protein 70 in human lens epithelial cells

    International Nuclear Information System (INIS)

    Sun Lixia; Ke Yao; Wang Kaijun; Lu Deqiang; Hu Huajun; Gao Xiangwei; Wang Baohong; Zheng Wei; Lou Jianling; Wu Wei

    2006-01-01

    To investigate the DNA damage, expression of heat shock protein 70 (Hsp70) and cell proliferation of human lens epithelial cells (hLEC) after exposure to the 1.8 GHz radiofrequency field (RF) of a global system for mobile communications (GSM). An Xc-1800 RF exposure system was used to employ a GSM signal at 1.8 GHz (217 Hz amplitude-modulated) with the output power in the specific absorption rate (SAR) of 1, 2 and 3 W/kg. After 2 h exposure to RF, the DNA damage of hLEC was accessed by comet assay at five different incubation times: 0, 30, 60, 120 and 240 min, respectively. Western blot and RT-PCR were used to determine the expression of Hsp70 in hLECs after RF exposure. The proliferation rate of cells was evaluated by bromodeoxyuridine incorporation on days 0, 1 and 4 after exposure. The results show that the difference of DNA-breaks between the exposed and sham-exposed (control) groups induced by 1 and 2 W/kg irradiation were not significant at any incubation time point (P > 0.05). The DNA damage caused by 3 W/kg irradiation was significantly increased at the times of 0 and 30 min after exposure (P 0.05). Detectable mRNA as well as protein expression of Hsp70 was found in all groups. Exposure at SARs of 2 and 3 W/kg for 2 h exhibited significantly increased Hsp70 protein expression (P 0.05). No difference of the cell proliferation rate between the sham-exposed and exposed cells was found at any exposure dose tested (P > 0.05). The results indicate that exposure to non-thermal dosages of RF for wireless communications can induce no or repairable DNA damage and the increased Hsp70 protein expression in hLECs occurred without change in the cell proliferation rate. The non-thermal stress response of Hsp70 protein increase to RF exposure might be involved in protecting hLEC from DNA damage and maintaining the cellular capacity for proliferation

  2. Effect of pectin and hemicellulose removal from hemp fibres on the mechanical properties of unidirectional hemp/epoxy composites

    DEFF Research Database (Denmark)

    Liu, Ming; Meyer, Anne S.; Fernando, Dinesh

    2016-01-01

    The objective of this study was to investigate the effect of pectin and hemicellulose removal from hemp fibres on the mechanical properties of hemp fibre/epoxy composites. Pectin removal by EDTA and endo-polygalacturonase (EPG) removed epidermal and parenchyma cells from hemp fibres and improved...

  3. Analysis of glass fibre sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2014-01-01

    surfaces are called sizing. The sizing influences the properties of the interface between fibres and a matrix, and subsequently affects mechanical properties of composites. In this work the sizing of commercially available glass fibres was analysed so as to study the composition and chemical structures......Glass fibre reinforced polymer composites are widely used for industrial and engineering applications which include construction, aerospace, automotive and wind energy industry. During the manufacturing glass fibres, they are surface-treated with an aqueous solution. This process and the treated....... Soxhlet extraction was used to extract components of the sizing from the glass fibres. The glass fibres, their extracts and coated glass plates were analysed by Thermo-Gravimetric Analysis combined with a mass spectrometer (TGA-MS), and Attenuated Total Reflectance Fourier Transform Infrared (ATR...

  4. CHARACTERISATION OF CASSAVA FIBRE FOR USE AS A BIOMATERIAL

    OpenAIRE

    Lois Larbie; Claude Fiifi Hayford; Elsie Effah Kaufmann

    2012-01-01

    In this study we investigate the cytotoxicity of de-starched cassava fibre granules and fine powder using human peripheral blood mononuclear cells (PBMC) and examine changes in the composition of Simulated Body Fluid (SBF) resulting from immersion of cassava fibre samples. The purpose of the study was to characterise cassavafibre for possible biomaterial applications. Preliminary results indicate insignificant cytotoxic effects on PBMCs with cassava sample concentrations of 0.1g/ml, 0.025g/ml...

  5. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    James, W.P.T.; Branch, W.J.; Southgate, D.A.T.

    1978-01-01

    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  6. Fibre constituents of some foods.

    Science.gov (United States)

    Rani, B; Kawatra, A

    1994-06-01

    Some plant foods viz. bottlegourd, carrot, cauliflower, cabbage, green bengalgram, pea, apple, plum, guava, karonda, blackgram husk and lentil husk were analysed for their dietary fibre components. The total dietary fibre contents of these foods varied from 14.68 to 78.21 percent on dry matter basis. As compared to fruits and vegetables, the husks had higher amount of total dietary fibre. Cellulose represented as the major fibre constituent in most of the foods whereas, husks were observed to be good sources of hemicellulose. All foods were low in pectin and lignin contents except guava.

  7. Advanced Fibre Based Energy Storage

    Science.gov (United States)

    Reid, Daniel Oliver

    New energy storage devices are required to enable future technologies. With the rise of wearable consumer and medical devices, a suitable flexible and wearable means of storing electrical energy is required. Fibre-based devices present a possible method of achieving this aim. Fibres are inherently more flexible than their bulk counterparts, and as such can be employed to form the electrodes of flexible batteries and capacitors. They also present a facile possibility for incorporation into many fabrics and clothes, further boosting their potential for use in wearable devices. Electrically conducting fibres were produced from a dispersion of carbon nanomaterials in a room temperature ionic liquid. Coagulation of this dispersion was achieved through manual injection into aqueous solutions of xanthan gum. The limitations of this method are highlighted by very low ultimate tensile strengths of these fibres, in the order of 3 MPa, with high variation within all of the fibres. Fibres were also produced via scrolling of bi-component films containing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(vinyl alcohol) (PVA). Chemical treatments were employed to impart water compatibility to these fibres, and their electrochemical, physical and electrical properties were analysed. Fibres were wet spun from two PEDOT:PSS sources, in several fibre diameters. The effect of chemical treatments on the fibres were investigated and compared. Short 5 min treatment times with dimethyl sulfoxide (DMSO) on 20 mum fibres produced from Clevios PH1000 were found to produce the best overall treatment. Up to a six-fold increase in electrical conductivity resulted, reaching 800 S cm-1, with up to 40 % increase in specific capacitance and no loss of mechanical strength (55 F g-1 and 150 MPa recorded). A wet spinning system to produce PEDOT:PSS fibres containing functionalised graphenes and carbon nanotubes, as well as birnessite nanotubes was subsequently developed

  8. A fibre optic displacement sensor

    OpenAIRE

    Sohlström, Hans; Holm, Ulf

    1982-01-01

    Fibre optics is beginning to find use for sensing purposes. Fibre optic sensors have many interesting features, e.g., their immunity to interference from electromagnetic fields. The paper briefly discusses different sensor principles. A displacement sensor using multimode, step index fibres is desccribed. Measurement data showing a resolution of 0.05 nm/sqrt(Hz) in a 150 µm linear range is given. In this sensor, the light coupling between two fibre ends varies with the position of a movable ...

  9. Age-related differences in signaling efficiency of human lens cells underpin differential wound healing response rates following cataract surgery.

    Science.gov (United States)

    Dawes, Lucy Jean; Duncan, George; Wormstone, Ian Michael

    2013-01-14

    Cataract surgery is blighted by posterior capsule opacification (PCO), which is more severe and frequent in the young than the elderly (>60 years). Our aim was to understand the biological basis for these age-related differences in PCO/wound healing rates. Human capsular bags were prepared by cataract surgery on donor lenses (young [60 years] groups) and maintained in serum-free Eagle's minimum essential medium. Cell growth was determined using the MTS assay. Fibroblast growth factor (FGF) and hepatocyte growth factor (HGF) levels were determined using ELISA. Protein synthesis rates were elucidated by 35S-methionine incorporation. U0126, SB203580, and SP600125 were used to disrupt ERK-, p38-, and JNK-mediated signaling, respectively. Level of total and phospho-ERK, -c-jun, -P38, and -JNK plus cytokines were detected using a BIOPLEX array system. Following a 2-day culture period, significant decreases in IL-1β and IL-6, and increases in IL-10, IL-12, IL-13, and VEGF in the >60 years group were observed compared with their younger counterparts. Capsular bags (cells and capsule) from aged donors contained greater than or equal levels of HGF and FGF than younger counterparts and had greater rates of protein synthesis. Inhibition of ERK, p38, and JNK signaling significantly suppressed cell coverage on the posterior capsule. pERK, p-c-jun, p-p38, and pJNK were consistently lower in aged cell populations; total signaling protein expression was unaffected by age. Serum stimulation increased pERK, p-c-jun, and pJNK levels in cells of all ages; p-p38 was significantly increased in the >60 years group only. Ligand availability to cells is not a limiting factor as we age, but the ability to convert this resource into signaling activity is. We therefore propose that overall signaling efficiency is reduced as a function of age, which consequently limits wound-healing response rates after injury.

  10. Regulation of the Two Delta Crystallin Genes during Lens Development in the Chicken Embryo

    Science.gov (United States)

    1991-08-22

    lens grows , the mitotical- ly active anterior epithelial cells move towards the equator of the lens from the fringe of the epithelium. As they pass...sequence derived from poliovirus RNA. Nature 334: 320-325. Philpott, G. W., Coulombre, A. J. Lens development. (1965). The differentiation of

  11. Non-Linear Fibres for Widely Tunable Femtosecond Fibre Lasers

    DEFF Research Database (Denmark)

    Pedersen, Martin Erland Vestergaard

    of a fusion splicer and a gas-line burner, is applied to the few-moded fibres. An intermodal four-wave mixing process and a novel intermodal Cerenkov generation process are demonstrated experimentally in one of the two speciality few-moded fibres. The two intermodal processes are described theoretically...

  12. Asbestos as 'toxic short-circuit' optic-fibre for UV within the cell-net: — Likely roles and hazards for secret UV and IR metabolism

    International Nuclear Information System (INIS)

    Traill, Robert R

    2011-01-01

    The most toxic asbestos fibres have widths 250nm-10nm, and this toxicity is 'physical', which could mean either mechanical or optical: Tangling with chromosomes is a mechanical hazard occasionally reported, and fibres 100nm wide — or chrysotile (white asbestos) is >150nm. In both cases, UV A /UV B -transmission would then predominate. (Chrysotile 150nm might be benign — escaping both mechanical and optical!). But what would generate such UV, and why would its transmission be toxic? Thar and Kühl (J.Theor.Biol.:2004) explain that the long mitochondria on microtubules may be able to act as UV-lasers, (and many observers since Gurwitsch 1923 have reported ultraweak UV emissions escaping from all types of living bio-tissue). That all suggests some universal secret role for UV, apparently related to mitosis. Insertion of fibre 'short-circuits' could then cause upsets in mitosis-control, and hence DNA irregularities. Such UV-control could parallel similar lower-powered Infra-Red control-systems (as considered elsewhere for coaxial myelin; or as portrayed by G.Albrecht-Buehler's online animations etc.); and the traditional short mitochondria seem better suited for this IR task.

  13. Impact of cell wall-degrading enzymes on water-holding capacity and solubility of dietary fibre in rye and wheat bran.

    Science.gov (United States)

    Petersson, Karin; Nordlund, Emilia; Tornberg, Eva; Eliasson, Ann-Charlotte; Buchert, Johanna

    2013-03-15

    Rye and wheat bran were treated with several xylanases and endoglucanases, and the effects on physicochemical properties such as solubility, viscosity, water-holding capacity and particle size as well as the chemical composition of the soluble and insoluble fractions of the bran were studied. A large number of enzymes with well-defined activities were used. This enabled a comparison between enzymes of different origins and with different activities as well as a comparison between the effects of the enzymes on rye and wheat bran. The xylanases derived from Bacillus subtilis were the most effective in solubilising dietary fibre from wheat and rye bran. There was a tendency for a higher degree of degradation of the soluble or solubilised dietary fibre in rye bran than in wheat bran when treated with most of the enzymes. None of the enzymes increased the water-holding capacity of the bran or the viscosity of the aqueous phase. The content of insoluble material decreased as the dietary fibre was solubilised by the enzymes. The amount of material that may form a network to retain water in the system was thereby decreased. © 2012 Society of Chemical Industry.

  14. Cytotoxicity of coated and uncoated fibre-reinforced composites.

    Science.gov (United States)

    Frese, Cornelia; Wolff, Diana; Zingler, Sebastian; Krueger, Tanja; Stucke, Kathrin; Lux, Christopher J; Staehle, Hans Joerg; Erber, Ralf

    2014-07-01

    Currently, there are many fibre-reinforced composites (FRCs) available which differ in the type and volume fraction of fibres, pre-treatment of fibres and matrix composition. The aims of this in vitro investigation were to determine whether there is a difference in biocompatibility of FRCs and if coating FRCs with resin composites influences their cytotoxic potential. Five different FRC materials were tested which were either uncoated or coated with flowable or viscous resin composite. Artificial saliva extracts were prepared according to USP-XXIII and ISO-10993 to determine cytotoxicity by testing cell viability and growth of primary human gingival fibroblasts (HGF) using MTT assay, LIVE/DEAD(®) assay and cell proliferation assay. The influence of eluates on fibres of the cytoskeleton was investigated by vimentin, tubulin and actinin immunostainings. A two-way ANOVA followed by Scheffe's post-hoc test, which included the factors FRC material and coating procedure, was performed to assess cytotoxicity. All extracts of FRC materials displayed minor cytotoxic potential on HGF cell viability, cell proliferation and integrity of the cytoskeleton. The type of FRC material significantly influenced cell viability (MTT assay) (p material resulted in altered cell viability. Distribution and organization of cytosolic fibres was not affected after HGF exposure to eluates. There is a lack of knowledge about the leaching behaviour of commonly available fully pre-impregnated FRCs and their interactions with coating materials. The coating of FRCs with resin composite materials did not impact biocompatibility.

  15. Leukotriene D4 activates distinct G-proteins in intestinal epithelial cells to regulate stress fibre formation and to generate intracellular Ca2+ mobilisation and ERK1/2 activation

    International Nuclear Information System (INIS)

    Nielsen, Christian Kamp; Massoumi, Ramin; Sonnerlind, Maria; Sjoelander, Anita

    2005-01-01

    We have shown that the pro-inflammatory mediator LTD 4 , via its G-protein-coupled receptor CysLT 1 , signals through both pertussis-toxin-sensitive and -insensitive G-proteins to induce various cellular responses. To further characterise the initial step of the different signalling pathways emanating from the CysLT 1 receptor, we transfected intestinal epithelial cells, Int 407, with different mini vectors that each express a specific inhibitory peptide directed against a unique α subunit of a specific heterotrimeric G-protein. Our results revealed that LTD 4 -induced stress fibre formation is inhibited approximately 80% by a vector expressing an inhibitory peptide against the pertussis-toxin-insensitive Gα 12 -protein in intestinal epithelial Int 407 cells. Control experiments revealed that the LPA-induced stress fibre formation, mediated via the Gα 12 -protein in other cell types, was blocked by the same peptide in intestinal Int 407 cells. Furthermore, the CysLT 1 -receptor-mediated calcium signal and activation of the proliferative ERK1/2 kinase are blocked in cells transfected with a vector expressing an inhibitory peptide against the Gα i3 -protein, whereas in cells transfected with an empty ECFP-vector or vectors expressing inhibitory peptides against the Gα i1-2 -, Gα 12 -, Gα R -proteins these signals are not significantly affected. Consequently, the CysLT 1 receptor has the capacity to activate at least two distinctly different heterotrimeric G-proteins that transduce activation of unique downstream cellular events

  16. Creep properties of discontinuous fibre composites with partly creeping fibres

    International Nuclear Information System (INIS)

    Bilde-Soerensen, J.B.; Lilholt, H.

    1977-05-01

    In a previous report (RISO-M-1810) the creep properties of discontinuous fibre composites with non-creeping fibres were analyzed. In the present report this analysis is extended to include the case of discontinuous composites with partly creeping fibres. It is shown that the creep properties of the composite at a given strain rate, epsilonsub(c), depend on the creep properties of the matrix at a strain rate higher than epsilonsub(c), and on the creep properties of the fibres at epsilonsub(c). The composite creep law is presented in a form which permits a graphical determination of the composite creep curve. This can be constructed on the basis of the matrix and the fibre creep curves by vector operations in a log epsilon vs. log sigma diagram. The matrix contribution to the creep strength can be evaluated by a simple method. (author)

  17. Microstructured Optical Fibres

    DEFF Research Database (Denmark)

    1999-01-01

    complete PBGs, which reflects light incident from air or vacuum. Such structures may be used as cladding structures in optical fibres, where light is confined and thereby guided in a hollow core region. In addition, the present invention relates to designs for ultra low-loss PBG waveguiding structures......The present invention relates to a new class of optical waveguides, in which waveguiding along one or more core regions is obtained through the application of the Photonic Bandgap (PBG) effect. The invention further relates to optimised two-dimensional lattice structures capable of providing...

  18. Scintillating-fibre calorimetry

    International Nuclear Information System (INIS)

    Livan, M.; Vercesi, V.; Wigmans, R.

    1995-01-01

    In the past decade, calorimetry based on scintillating plastic fibres as active elements was developed from a conceptual idea to a mature detector technology, which is nowadays widely applied in particle physics experiments. This development and the performance characteristics of representative calorimeters, both for the detection of electromagnetic and hadronic showers, are reviewed. We also discuss new information on shower development processes in dense matter and its application to calorimetric principles that has emerged from some very thorough studies that were performed in the framework of this development. (orig.)

  19. Factors Determining the Oxygen Permeability of Biological Membranes: Oxygen Transport Across Eye Lens Fiber-Cell Plasma Membranes.

    Science.gov (United States)

    Subczynski, Witold Karol; Widomska, Justyna; Mainali, Laxman

    2017-01-01

    Electron paramagnetic resonance (EPR) spin-label oximetry allows the oxygen permeability coefficient to be evaluated across homogeneous lipid bilayer membranes and, in some cases, across coexisting membrane domains without their physical separation. The most pronounced effect on oxygen permeability is observed for cholesterol, which additionally induces the formation of membrane domains. In intact biological membranes, integral proteins induce the formation of boundary and trapped lipid domains with a low oxygen permeability. The effective oxygen permeability coefficient across the intact biological membrane is affected not only by the oxygen permeability coefficients evaluated for each lipid domain but also by the surface area occupied by these domains in the membrane. All these factors observed in fiber cell plasma membranes of clear human eye lenses are reviewed here.

  20. Properties of hemp fibre polymer composites - An optimisation of fibre properties using novel defibration methods and fibre characterisation

    DEFF Research Database (Denmark)

    Thygesen, Anders

    2006-01-01

    Characterization of hemp fibres was carried out with fibres obtained with low handling damage and defibration damage to get an indication of how strong cellulose based fibres that can be produced from hemp. Comparison was made with hemp yarn producedunder traditional conditions where damage...... obtained by steam explosion of hemp fibres prior defibrated with pectin degrading enzymes. The S2 layer in the fibre wall of the hemp fibres consisted of1-4 cellulose rich and lignin poor concentric layers constructed of ca. 100 nm thick lamellae. The microfibril angle showed values in the range 0......-10° for the main part of the S2-layer and 70-90° for the S1-layer. The microfibrils that are mainly parallelwith the fibre axis explain the high fibre stiffness, which in defibrated hemp fibres reached 94 GPa. The defibrated hemp fibres had higher fibre stiffness (88-94 GPa) than hemp yarn (60 GPa), which...

  1. Geometrical frustration yields fibre formation in self-assembly

    Science.gov (United States)

    Lenz, Martin; Witten, Thomas A.

    2017-11-01

    Controlling the self-assembly of supramolecular structures is vital for living cells, and a central challenge for engineering at the nano- and microscales. Nevertheless, even particles without optimized shapes can robustly form well-defined morphologies. This is the case in numerous medical conditions where normally soluble proteins aggregate into fibres. Beyond the diversity of molecular mechanisms involved, we propose that fibres generically arise from the aggregation of irregular particles with short-range interactions. Using a minimal model of ill-fitting, sticky particles, we demonstrate robust fibre formation for a variety of particle shapes and aggregation conditions. Geometrical frustration plays a crucial role in this process, and accounts for the range of parameters in which fibres form as well as for their metastable character.

  2. Design of optical fibres with advanced modal control properties

    DEFF Research Database (Denmark)

    Muliar, Olena

    an experimental characterisation of the modelled 19-cell HC PBGF was conducted. A modal content evaluation within a broad wavelength range was performed by a modified S 2 technique with a spectrogram approach. Results of the experimental and numerical fibre analysis were compared. It was revealed, that in 10m...... has increased interest to HOMs as independent spatial data channels for mode division multiplexing (MDM). The primary aim of this thesis is the investigation, modelling and experimental evaluation of HOMs in an optical fibre of advanced design, suitable for a MDM implementation. In order to achieve...... this goal, an interferometric-based fibre characterisation technique, known as a cross-correlated (C 2 ) imaging, was explored. An alternative modal reconstruction approach by 2D Fourier transform was presented, that allowed to extract intensity and phase distributions of the fibre mode from a single...

  3. Surface-Enhanced Raman Spectroscopy (SERS Tracking of Chelerythrine, a Na+/K+ Pump Inhibitor, into Cytosol and Plasma Membrane Fractions of Human Lens Epithelial Cell Cultures

    Directory of Open Access Journals (Sweden)

    Kevin M. Dorney

    2013-12-01

    Full Text Available Background/Aims: The quaternary benzo-phenanthridine alkaloid (QBA chelerythrine (CET is a pro-apoptotic drug and Na+/K+ pump (NKP inhibitor in human lens epithelial cells (HLECs. In order to obtain further insight into the mechanism of NKP inhibition by CET, its sub-cellular distribution was quantified in cytosolic and membrane fractions of HLEC cultures by surface-enhanced Raman spectroscopy (SERS. Methods: Silver nanoparticles (AgNPs prepared by the Creighton method were concentrated, and size-selected using a one-step tangential flow filtration approach. HLECs cultures were exposed to 50 μM CET in 300 mOsM phosphate-buffered NaCl for 30 min. A variety of cytosolic extracts, crude and purified membranes, prepared in lysing solutions in the presence and absence of a non-ionic detergent, were incubated with AgNPs and subjected to SERS analysis. Determinations of CET were based on a linear calibration plot of the integrated CET SERS intensity at its 659 cm-1 marker band as a function of CET concentration. Results: SERS detected chemically unaltered CET in both cytosol and plasma membrane fractions. Normalized for protein, the CET content was some 100 fold higher in the crude and purified plasma membrane fraction than in the soluble cytosolic extract. The total free CET concentration in the cytosol, free of membranes or containing detergent-solubilized membrane material, approached that of the incubation medium of HLECs. Conclusion: Given a negative membrane potential of HLECs the data suggest, but do not prove, that CET may traverse the plasma membrane as a positively charged monomer (CET+ accumulating near or above passive equilibrium distribution. These findings may contribute to a recently proposed hypothesis that CET binds to and inhibits the NKP through its cytosolic aspect.

  4. Analysis of glass fibre sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2014-01-01

    . Soxhlet extraction was used to extract components of the sizing from the glass fibres. The glass fibres, their extracts and coated glass plates were analysed by Thermo-Gravimetric Analysis combined with a mass spectrometer (TGA-MS), and Attenuated Total Reflectance Fourier Transform Infrared (ATR...

  5. Design of DFB fibre lasers

    DEFF Research Database (Denmark)

    Lauridsen, Vibeke Claudia; Povlsen, Jørn Hedegaard; Varming, Poul

    1998-01-01

    A numerical model for erbium distributed feedback (DFB) fibre lasers is presented. The model is used to optimise the location of a discrete phase-shift to obtain maximum output power. For DFB fibre lasers of up to 10cm in length it is shown that the influence of Kerr nonlinearity with respect...

  6. Design of DFB fibre lasers

    DEFF Research Database (Denmark)

    Lauridsen, Vibeke Claudia; Povlsen, Jørn Hedegaard; Varming, Poul

    1998-01-01

    A numerical model for erbium distributed feedback (DFB) fibre lasers is presented. The model is used to optimise the location of a discrete phase-shift to obtain maximum output power. For DFB fibre lasers of up to 10cm in length it is shown that the influence of Kerr nonlinearity with respect to ...... to output power is negligible....

  7. A catoptric lens

    International Nuclear Information System (INIS)

    Rambauske, W.R.

    1973-01-01

    The invention relates to a catoptric lens for combining energies transmitted by several sources such as lasers; said lens comprising mirrors, the reflective surfaces of which have their focuses spaced from a common axis of symmetry. By means of these reflecting surfaces, which are generated by the nutation of portions of quadratic conics about the axis of symmetry, it is possible to focus the energy emmited by several lasers at the focus of the exit-mirror reflecting surface. This can be applied to thermonuclear fusion [fr

  8. The murine lens: A model to investigate in vivo epithelial-mesenchymal transition.

    Science.gov (United States)

    Shirai, Kumi; Tanaka, Sai-Ichi; Lovicu, Frank J; Saika, Shizuya

    2018-03-01

    Epithelial-mesenchymal transition (EMT) produces myofibroblasts that contribute to the formation of fibrotic tissue with an impairment of tissue homeostasis and functionality. The crystalline lens of the eye is a unique transparent and isolated tissue. The lens vesicle becomes isolated from the surface ectoderm, its cells are all contained as they line the inner surface of the lens capsule. Clinically the formation of fibrotic tissue by the lens epithelial cells causes a type of cataract or opacification and contraction of the lens capsule postcataract surgery. Production of EMT in the intact animal lens by using specific gene transfer to the lens or experimental lens injury has been shown to be a powerful tool to investigate EMT processes. It is not easy to uncover whether the origin of the myofibroblast is epithelial cell-derived or from other cell lineages in fibrotic tissues. However, myofibroblasts that appear in the crystalline lens pathology are totally derived from the lens epithelial cells for the reasons mentioned above. Here, we report on different animal models of lens EMT, using either transgenic approaches or injury to study the biological aspects of EMT. Developmental Dynamics 247:340-345, 2018. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.

  9. Ultrastructural effects of silicone oil on the clear crystalline lens of the human eye.

    Science.gov (United States)

    Soliman, Wael; Sharaf, Mohamed; Abdelazeem, Khaled; El-Gamal, Dalia; Nafady, Allam

    2018-03-01

    To evaluate light and electron microscopic changes of the anterior capsule and its epithelium after clear lens extraction of vitrectomized myopic eyes with silicone oil tamponade. This prospective, controlled, non-randomized, interventional study included 20 anterior lens capsular specimens that were excised during combined clear lens extraction and silicone oil removal from previously vitrectomized highly myopic patients with silicone oil tamponade for previous retinal detachment surgeries. The specimens were examined via light microscopy and electron microscopy and compared with 20 anterior capsule specimens removed during clear lens extraction of non-vitrectomized highly myopic eyes. Light microscopic examination of clear lens anterior capsule specimens of vitrectomized myopic eyes filled with silicone oil showed relatively more flat cells with irregular outline of lens' epithelial cells with wide intercellular spaces, deeply stained nuclei, and multiple intracytoplasmic vacuoles. Scanning electron microscopy revealed collagenous surfaces filled with multiple pits, depressions, and abnormal deposits. Transmission electron microscopy revealed lens epithelial cells with apoptotic changes, many cytoplasmic vacuoles, and filopodia-like protrusions between lens epithelial cells and the capsule. Epithelial proliferation and multilayering were also observed. silicone oil may play a role in the development of apoptotic and histopathological changes in clear lens epithelial cells. Clarity of the lens at the time of silicone oil removal does not indicate an absence of cataractous changes. We found justification of combined clear lens extraction and silicone oil removal or combined phacovitrectomy when silicone oil injection is planned, but further long-term studies with larger patient groups are required.

  10. Aligned flax fibre/polylactate composites

    DEFF Research Database (Denmark)

    Madsen, Bo; Lilholt, Hans; Thygesen, Anders

    2008-01-01

    are well predicted by the model. The back-calculated effective stiffness and failure stress of the flax fibres are in the ranges 56-60 GPa and 515-730 MPa, respectively. Finally, the model is used for parametric analysis and overall guidelines for the comparisons between tensile performance of flax fibre......The potential of biocomposites in engineering applications is demonstrated by using aligned flax fibre/polylactate composites as a materials model system. The failure stress of flax fibres is measured by tensile testing of single fibres and fibre bundles. For both fibre configurations, it is found...... that failure stress is decreased by increasing the tested fibre volume. Based on two types of flax fibre preforms: carded sliver and unidirectional non-crimp fabric, aligned flax fibre/polylactate composites were fabricated with variable fibre content. The volumetric composition and tensile properties...

  11. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

    Thomsen, Louiza Bohn; Jörntell, Henrik; Midtgaard, Jens

    2010-01-01

    affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could......Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX......)-sensitive fast Na(+) spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers...

  12. Biscuits with No Added Sugar Containing Stevia, Coffee Fibre and Fructooligosaccharides Modifies α-Glucosidase Activity and the Release of GLP-1 from HuTu-80 Cells and Serotonin from Caco-2 Cells after In Vitro Digestion

    Science.gov (United States)

    Martinez-Saez, Nuria; Hochkogler, Christina Maria; Somoza, Veronika; del Castillo, Maria Dolores

    2017-01-01

    This study assessed the in vitro effects of the bioaccessible food components released during the simulated human digestion of a coffee fibre-containing biscuit (CFB) on α-glucosidase activity, antioxidant capacity and satiety hormones. Digest of CFB presented a significantly (p < 0.05) lower amount of sugar (68.6 mg/g) and a higher antioxidant capacity (15.1 mg chlorogenic acid eq./g) than that of a sucrose-containing biscuit (SCB). The CFB significantly reduced (p < 0.05) α-glucosidase activity (IC50 = 3.3 mg/mL) compared to the SCB (IC50 = 6.2 mg/mL). Serotonin and glucagon-like peptide-1 (GLP-1) release by differentiated Caco-2 and HuTu-80 cells, respectively, was stimulated by the CFB (355% at a concentration of 0.5 mg/mL and 278% at a concentration of 0.05 mg/mL) to the same order of magnitude as those of the SCB. To summarize, the CFB was demonstrated to reduce monosaccharide bioaccessibility, to inhibit a diabetes-related digestive enzyme, and to improve the release of satiety hormones. PMID:28677657

  13. Biscuits with No Added Sugar Containing Stevia, Coffee Fibre and Fructooligosaccharides Modifies α-Glucosidase Activity and the Release of GLP-1 from HuTu-80 Cells and Serotonin from Caco-2 Cells after In Vitro Digestion.

    Science.gov (United States)

    Martinez-Saez, Nuria; Hochkogler, Christina Maria; Somoza, Veronika; Del Castillo, Maria Dolores

    2017-07-04

    This study assessed the in vitro effects of the bioaccessible food components released during the simulated human digestion of a coffee fibre-containing biscuit (CFB) on α-glucosidase activity, antioxidant capacity and satiety hormones. Digest of CFB presented a significantly ( p < 0.05) lower amount of sugar (68.6 mg/g) and a higher antioxidant capacity (15.1 mg chlorogenic acid eq./g) than that of a sucrose-containing biscuit (SCB). The CFB significantly reduced ( p < 0.05) α-glucosidase activity (IC50 = 3.3 mg/mL) compared to the SCB (IC50 = 6.2 mg/mL). Serotonin and glucagon-like peptide-1 (GLP-1) release by differentiated Caco-2 and HuTu-80 cells, respectively, was stimulated by the CFB (355% at a concentration of 0.5 mg/mL and 278% at a concentration of 0.05 mg/mL) to the same order of magnitude as those of the SCB. To summarize, the CFB was demonstrated to reduce monosaccharide bioaccessibility, to inhibit a diabetes-related digestive enzyme, and to improve the release of satiety hormones.

  14. Bast fibre content, fibre yield and fibre quality of different linseed genotypes

    Directory of Open Access Journals (Sweden)

    H. SANKARI

    2008-12-01

    Full Text Available Linseed (Linum usitatissimum L. grown for seed does not compete well with flax in fibre yield, but as a by-product of seed production its stems could be used in non-woven products. With the aim of discovering suitable linseed genotypes to be cultivated for dual-purpose use in Finland, Finnish linseed cv. Helmi was compared with ten other linseed genotypes and one flax cultivar for stem yield, bast fibre content in stem, stem length and diameter and bast fibre yield. In addition, breaking tenacity and elongation at break of the fibres were determined. The experiments were carried out in 1996B1997 at the Agricultural Research Centre (MTT in Jokioinen, Finland (latitude 60o49'N. Bast fibre content in stem averaged 16.9% and breeding line Bor 18 had significantly higher bast fibre content than cv. Helmi. Bast fibre yield averaged 301 kg dry matter ha-1. Compared with cv. Helmi, breeding lines Bor 15 and Bor 18 and cvs. Flanders and Gold Merchant produced significantly higher fibre yield. The median for breaking tenacity varied among the genotypes between 41 and 67 cN/tex and the median for elongation at break between 3.5 and 6.8%. Finnish breeding line Bor 18 is recommended for cultivation as dual-purpose linseed in Finland. ;

  15. Radiation studies in Lens culinaris

    International Nuclear Information System (INIS)

    Sinha, S.S.N.

    1977-01-01

    Estimation of chromosomal aberrations in flowers of Lens culinaris according to their sequence of development in the plants at 4, 8 and 12 Kr in the M 1 generation, showed that the later formed flowers had smaller percentages of cells with aberrations than those developed earlier. It is suggested that this may be the result of competition between more damaged and less damaged cells during the development of the shoot. There is consequently a decrease of sterility in successive flowers. The numbers of karyotypes taking part in the formation of lower and uppermost flowers were estimated cytologically at 4, 8 and 12 Kr. It was found that more karyotypes were involved in the formation of the lower flowers than in the upper ones. It appeared that at lower doses larger numbers of karyotypes were taking part in the formation of the chimaera than at higher doses. (auth.)

  16. Quadrupole magnetic lens

    International Nuclear Information System (INIS)

    Piskunov, V.A.

    1981-01-01

    The following connection of windings of electromagnet is suggested for simplification of the design of qUadrupole magnetic lens intended for use in radiotechnical and electron-optical devices. The mentioned windings are connected with each other by a bridge scheme and the variable resistors are switched in its diagonals in the lens containing four electromagnet with windings connected with two variable resistors the mobile contacts of which are connected with a direct current source. Current redistribution between left windings and right windings takes place at shift of mobile contact of variable resistor, and current redistribution between upper and low coils of electromagnets takes place at shifting mobile contact of the other variable resistor. In this case smooth and independent electron-optical misalignment of lens by two mutually perpendicular directions proceeds. Use of the given design of the lens in the oscillograph permits to use printing assembly for alignment plate and to reduce the number of connections at the expense of decreasing the number of resistors

  17. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into the cornea. Even if you have perfect vision, you need to get an eye exam and a prescription ...

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ...

  19. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  20. The Lens of Chemistry

    Science.gov (United States)

    Thalos, Mariam

    2013-01-01

    Chemistry possesses a distinctive theoretical lens--a distinctive set of theoretical concerns regarding the dynamics and transformations of a perplexing variety of organic and nonorganic substances--to which it must be faithful. Even if it is true that chemical facts bear a special (reductive) relationship to physical facts, nonetheless it will…

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her with a corneal ... A recent article from U.S. News and World Report explains what ophthalmologists are and how they can ...

  2. bubble chamber lens

    CERN Multimedia

    Was used in a PS experiment. Before the days of electronic detectors, visual techniques were used to detect particles, using detectors such as spark chambers and bubble chambers. This plexiglass lens was used to focus the image of tracks so they could be photographed.

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... an Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact ... After One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter ...

  4. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    Science.gov (United States)

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  5. EXERCISE MYOPATHY: CHANGES IN MYOFIBRILS OF FAST-TWITCH MUSCLE FIBRES

    Directory of Open Access Journals (Sweden)

    P. Kaasik

    2014-08-01

    Full Text Available The purpose of the present study was to determine the relationships between the changes of myofibrils in fast-twitch oxidative-glycolytic (type IIA fibres and fast-twitch glycolytic (type IIB muscle fibres, protein synthesis and degradation rate in exercise-induced myopathic skeletal muscle. Exhaustive exercise was used to induce myopathy in Wistar rats. Intensity of glycogenolysis in muscle fibres during exercise, protein synthesis rate, degradation rate and structural changes of myofibrils were measured using morphological and biochemical methods. Myofibril cross sectional area (CSA in type IIA fibres decreased 33% and type IIB fibres 44%. Protein degradation rate increased in both type IIA and IIB fibres, 63% and 69% respectively in comparison with the control group. According to the intensity of glycogenolysis, fast oxidative-glycolytic fibres are recruited more frequently during overtraining. Myofibrils in both types of fast-twitch myopathic muscle fibres are significantly thinner as the result of more intensive protein degradation. Regeneration capacity according to the presence of satellite cells is higher in type IIA fibres than in type IIB fibres in myopathic muscle.

  6. Clinical survey of lens care in contact lens patients.

    Science.gov (United States)

    Ky, W; Scherick, K; Stenson, S

    1998-10-01

    Overall, contact lenses provide a safe and effective modality for vision correction. However, problems do occasionally arise. Up to 80% of contact lens complications can be traced to poor patient compliance with recommended lens care guidelines. We conducted a survey to evaluate the level of patient compliance in specific areas of lens care and maintenance and to assess patient knowledge of basic contact lens information. Patients were asked to complete an anonymous 15 question survey that focused on lens care--specifically the use of contact lens cleaners, methods of disinfection, enzyme treatments, use of rewetting drops, and the frequency of follow-up exams. In addition, the survey included six true/false questions relating to contact lens care and safety. There were a total of 103 participants in the study. Approximately 24% of patients stated they never cleaned their lenses prior to disinfection, and 5% used saline solutions as their primary mode of disinfection. A sizable portion of those surveyed (43% of soft lens wearers and 71% of rigid gas permeable lens wearers) either never used enzyme cleaners or used them less than once a month. Seventy percent of patients either never used rewetting drops or used them less than once a day. Twenty-nine percent of patients consulted their eye care professionals every 2 years and 6% less often than every two years. Six questions assessed patient knowledge of contact lens care safety. Of a possible six out of six correct answers, the mean number of correct responses was 3.74. A sizable proportion of contact lens wearers do not adequately adhere to recommended contact lens care, and many have an inadequate understanding of contact lens care guidelines. Therefore, it is important that practitioners place more emphasis on patient education at the time of initial contact lens fitting and reinforce such instruction during follow-up visits.

  7. [The influence of EphA2 overexpression on proliferation and apoptosis of human lens epithelial cells exposed to high-concentration dexamethasone in vitro].

    Science.gov (United States)

    Ma, C X; Zheng, G Y

    2018-02-11

    Objective: To construct lentiviral-mediated EphA2 overexpression vectors, transfect them into human lens epithelial cells (HLE-B3) in vitro , and investigate the effect of EphA2 gene overexpression on the proliferation and apoptosis of HLE-B3 exposed to high-concentration dexamethasone. Methods: Experimental Study. The pCDH-CMV- MCS-EF1-RFP plasmid was set up by the digestion of NOTⅠand XbaⅠ double restriction enzyme and ligation of CE ligase, and then the plasmid was transformed into DH10B cells. Seven clons were picked for enzymatic digestion and the clons with correct results were chosen for sequencing. The 293 T/17 cells were co-transfected with the pCDH-CMV-MCS-EF1-RFP-EphA2 and the packaging mixture by Lipofectamine 2000. At different multiplicities of infection (MOI=20, 50, 100, and 200) after 72-hour infection, we observed the expression of RFP and morphological changes of HLE-B3 by an inverted fluorescence microscope, and calculated the transfection efficiency through the flow cytometry. EphA2 protein expression was detected by Western blot. The following experiments were divided into four groups: normal control group (group A), EphA2 overexpression vector transfection group (group B), HLE-B3 cells exposed to dexamethasone group (group C) and EphA2 overexpression vector transfection HLE-B3 cells exposed to dexamethasone group (group D). Statistical analysis method was single factor or two factors variance analysis. Cell survival rate was detected by the Cell Counting Kit-8 assay. Cell apoptosis index was detected by Tunel. Results: Restriction enzyme digestion and sequencing indicated that EphA2 cDNA fragment was successfully inserted in the vector. The infection efficiency was up to 38.6%±3.9%, 49.2%±4.2%, 79.5%±5.5% and 80.2%±6.0% when the MOI was 20, 50, 100 and 200, respectively. There was statistically significant difference ( F= 2 600.8, P= 0.001) among the four groups and between any two groups except between the MOI=100 group and MOI=200

  8. Dispersion properties of photonic crystal fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Dridi, Kim

    1998-01-01

    Approximate dispersion and bending properties of all-silica two-dimensional photonic crystal fibres are characterised by the combination of an effective-index model and classical analysis tools for optical fibres. We believe for the first time to have predicted the dispersion properties of photonic...... crystal fibres. The results strongly indicate that these fibres have potential applications as dispersion managing components...

  9. Photonic crystal based polarization insensitive flat lens

    Science.gov (United States)

    Turduev, M.; Bor, E.; Kurt, H.

    2017-07-01

    The paper proposes a new design of an inhomogeneous artificially created photonic crystal lens structure consisting of annular dielectric rods to efficiently focus both transverse electric and transverse magnetic polarizations of light into the same focal point. The locations of each individual cell that contains the annular dielectric rods are determined according to a nonlinear distribution function. The inner and outer radii of the annular photonic dielectric rods are optimized with respect to the polarization insensitive frequency response of the transmission spectrum of the lens structure. The physical background of the polarization insensitive focusing mechanism is investigated in both spatial and frequency domains. Moreover, polarization independent wavefront transformation/focusing has been explored in detail by investigating the dispersion relation of the structure. Corresponding phase index distribution of the lens is attained for polarization insensitive normalized frequency range of a/λ  =  0.280 and a/λ  =  0.300, where a denotes the lattice constant of the designed structure and λ denotes the wavelength of the incident light. We show the wave transformation performance and focal point movement dynamics for both polarizations of the lens structure by specially adjusting the length of the structure. The 3D finite-difference time domain numerical analysis is also performed to verifiy that the proposed design is able to focus the wave regardless of polarization into approximately the same focal point (difference between focal distances of both polarizations stays below 0.25λ) with an operating bandwidth of 4.30% between 1476 nm and 1541 nm at telecom wavelengths. The main superiorities of the proposed lens structure are being all dielectric and compact, and having flat front and back surfaces, rendering the proposed lens design more practical in the photonic integration process in various applications such as optical switch

  10. Use of fibre wastes from production of acetate fibres

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-07-01

    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.

  11. Fibre Bragg grating and no-core fibre sensors

    CERN Document Server

    Daud, Suzairi

    2018-01-01

    This book focuses on the development and set-up of fibre Bragg grating (FBG) and no-core fibre (NCF) sensors. It discusses the properties of the sensors and modelling of the resulting devices, which include electronic, optoelectronic, photovoltaic, and spintronic devices. In addition to providing detailed explanations of the properties of FBG and NCF sensors, it features a wealth of instructive illustrations and tables, helping to visualize the respective devices’ functions.

  12. Intracapsular Lens Extraction for the Treatment of Pupillary Block Glaucoma Associated with Anterior Subluxation of the Crystalline Lens

    Directory of Open Access Journals (Sweden)

    Yong Joon Kim

    2013-11-01

    Full Text Available Purpose: To report a case of pupillary block glaucoma associated with spontaneous crystalline lens subluxation into the anterior chamber in a 34-year-old man. Methods: Dry vitrectomy was performed for securing enough retrolental space, and an intracapsular lens extraction was then performed via a corneolimbal incision. Additional endothelial cell damage was avoided with an injection of viscoelastics and gentle extraction of the crystalline lens. After deepening of the anterior chamber, scleral fixation of the intraocular lens was performed with an ab externo technique. Results: Two months after the operation, a well-fixated intraocular lens was observed and intraocular pressure was stable. The postoperative corneal astigmatism was -3.5 dpt, and the patient had a best-corrected visual acuity of 20/25. Postoperative complications included decreased endothelial cell count and sector iris paralysis near the incision site. Conclusions: An anteriorly subluxated crystalline lens can cause pupillary block glaucoma in healthy young adults. To prevent intraoperative complications, intracapsular lens extraction with dry vitrectomy can be a good surgical option. The endothelial cell density should be closely monitored after surgery.

  13. Intracapsular Lens Extraction for the Treatment of Pupillary Block Glaucoma Associated with Anterior Subluxation of the Crystalline Lens

    Science.gov (United States)

    Kim, Yong Joon; Ha, Seung Joo

    2013-01-01

    Purpose To report a case of pupillary block glaucoma associated with spontaneous crystalline lens subluxation into the anterior chamber in a 34-year-old man. Methods Dry vitrectomy was performed for securing enough retrolental space, and an intracapsular lens extraction was then performed via a corneolimbal incision. Additional endothelial cell damage was avoided with an injection of viscoelastics and gentle extraction of the crystalline lens. After deepening of the anterior chamber, scleral fixation of the intraocular lens was performed with an ab externo technique. Results Two months after the operation, a well-fixated intraocular lens was observed and intraocular pressure was stable. The postoperative corneal astigmatism was −3.5 dpt, and the patient had a best-corrected visual acuity of 20/25. Postoperative complications included decreased endothelial cell count and sector iris paralysis near the incision site. Conclusions An anteriorly subluxated crystalline lens can cause pupillary block glaucoma in healthy young adults. To prevent intraoperative complications, intracapsular lens extraction with dry vitrectomy can be a good surgical option. The endothelial cell density should be closely monitored after surgery. PMID:24348413

  14. The Chemical Composition of Grape Fibre

    OpenAIRE

    Jolana Karovičová; Zlatica Kohajdová; Lucia Minarovičová; Veronika Kuchtová

    2015-01-01

    Dietary fibres from cereals are much more used than dietary fibres from fruits; however, dietary fibres from fruits have better quality. In recent years, for economic and environmental reasons, there has been a growing pressure to recover and exploit food wastes. Grape fibre is used to fortify baked goods, because the fibre can lower blood sugar, cut cholesterol and may even prevent colon cancer. Grape pomace is a functional ingredient in bakery goods to increase total phenolic content and di...

  15. Characterisation of natural fibre reinforced PLA foams prepared by supercritical CO2 assisted extrusion

    Directory of Open Access Journals (Sweden)

    K. Bocz

    2016-09-01

    Full Text Available Natural fibre reinforced polylactic acid (PLA foams, as potential green replacements for petroleum-based polymer foams, were investigated. Highly porous (ε > 95% microcellular PLA foams were manufactured by supercritical CO2 assisted extrusion process. To overcome the inherently low melt strength of PLA, epoxy-functionalized chain extender was applied, while talc was added to improve its crystallization kinetics. The combined application of chain extender and talc effectively promoted the formation of uniform cell structures. The effect of cellulose and basalt fibre reinforcement on the foamability, morphology, structure and mechanical properties of the PLA foams were investigated as well. The addition of 5 wt% natural fibres promoted the cell nucleation, but caused non-uniform distribution of cell size due to the microholes induced by local fibre-matrix debonding. The compression strength of the manufactured basalt fibre reinforced PLA foams reached 40 kPa.

  16. The effects of growth conditions and of processing into yarn on dislocations in hemp fibres

    DEFF Research Database (Denmark)

    Thygesen, Lisbeth Garbrecht

    2011-01-01

    at harvest in hemp fibres from plants grown in a green house under three different regimes (wind free, windy and dry) with the percentage found in commercial hemp yarn. As expected a higher percentage of the cell wall consisted of dislocations in the processed fibres, but the increase was only significant...

  17. Mapping of kisspeptin fibres in the brain of the pro-oestrus rat

    DEFF Research Database (Denmark)

    Desroziers, E; Mikkelsen, J; Simonneaux, V

    2010-01-01

    throughout the external layer including around the deeper part of the infundibular recess. Most regions of immunoreactive cells and fibres matched perfectly for the two antibodies. However, fibres in the dorso-lateral septum, anterior fornix, accumbens nucleus and the lateral bed nucleus of the stria...

  18. Modeling of photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Barkou, Stig Eigil

    1999-01-01

    Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated.......Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated....

  19. Advanced fibre based energy storage.

    OpenAIRE

    Reid, Daniel

    2017-01-01

    New energy storage devices are required to enable future technologies. With the rise of wearable consumer and medical devices, a suitable flexible and wearable means of storing electrical energy is required. Fibre-based devices present a possible method of achieving this aim. Fibres are inherently more flexible than their bulk counterparts, and as such can be employed to form the electrodes of flexible batteries and capacitors. They also present a facile possibility for incorporation into man...

  20. Rigid polyurethane/oil palm fibre biocomposite foam

    Science.gov (United States)

    Alis, Adilah; Majid, Rohah A.; Nasir, Izzah Athirah Ahmad; Mustaffa, Nor Syatika; Hassan, Wan Hasamuddin Wan

    2017-07-01

    Rigid polyurethane (PU) biocomposite foam had been successfully prepared by reacting palm oil-derived polyol (PO-p) with polymeric 4, 4-diphenylmethane diisocynate (p-MDI). Two types of alkali-treated oil palm fibres namely, empty fruit bunch (EFB) and palm pressed fibre (PPF) were used as fillers to be incorporated into PU foam at 2.5 wt%, 5 wt% and 7.5 wt% fibre loadings. The effects of these fibres on surface morphology, compressive strength and thermal transition behaviours of biocomposite foams were investigated. Fourier transform infra-red (FTIR) analysis confirmed the formation of urethane linkages (-NHCOO) in all samples at 1530-1540 cm-1. Differential scanning calorimetry (DSC) analysis showed the average melting peak temperature (Tm) of biocomposite foams (132°C) were lower Tm than that of pure PU foam (161.67°C) and the increase amount of fibres did not give significant effect on the Tm of both biocomposite systems. Meanwhile, the microscopic images of PU-PPF foams exhibited smaller and uniform cell size morphologies compared with the PU-EFB foams that had coarse and irregular cell sizes, especially at 7.5wt% EFB. These findings were manifested with the gradually increase of compressive strength of PU-PPF at all PPF ratios while for PU-EFB system, the compressive strength increased up to 5 wt% before reduced at 7.5 wt% loading. It was thought due to the residual oil in PPF fibre had plasticized the PU matrix to a little extent, thus helping the dispersion of PPF fibre across the matrix.

  1. [Correct contact lens hygiene].

    Science.gov (United States)

    Blümle, S; Kaercher, T; Khaireddin, R

    2013-06-01

    Although contact lenses have long been established in ophthalmology, practical aspects of handling contact lenses is becoming increasingly less important in the clinical training as specialist for ophthalmology. Simultaneously, for many reasons injuries due to wearing contact lenses are increasing. In order to correct this discrepancy, information on contact lenses and practical experience with them must be substantially increased from a medical perspective. This review article deals with the most important aspects for prevention of complications, i.e. contact lens hygiene.

  2. The Chemical Composition of Grape Fibre

    Directory of Open Access Journals (Sweden)

    Jolana Karovičová

    2015-05-01

    Full Text Available Dietary fibres from cereals are much more used than dietary fibres from fruits; however, dietary fibres from fruits have better quality. In recent years, for economic and environmental reasons, there has been a growing pressure to recover and exploit food wastes. Grape fibre is used to fortify baked goods, because the fibre can lower blood sugar, cut cholesterol and may even prevent colon cancer. Grape pomace is a functional ingredient in bakery goods to increase total phenolic content and dietary fibre in nourishment. The aim of this study was to determine the chemical composition of commercial fibres, obtained from different Grape sources concerning their chemical properties such as moisture, ash, fat, protein, total dietary fibre. The chemical composition of Grape fibre is known to vary depending on the Grape cultivar, growth climates, and processing conditions. The obliged characteristics of the fibre product are: total dietary fibre content above 50%, moisture lower than 9%, low content of lipids, a low energy value and neutral flavour and taste. Grape pomace represents a rich source of various high-value products such as ethanol, tartrates and malates, citric acid, Grape seed oil, hydrocolloids and dietary fibre. Used commercial Grape fibres have as a main characteristic, the high content of total dietary fibre. Amount of total dietary fibre depends on the variety of Grapes. Total dietary fibre content (TDF in our samples of Grape fibre varied from 56.8% to 83.6%. There were also determined low contents of moisture (below 9%. In the samples of Grape fibre were determined higher amount of protein (8.6 - 10.8%, mineral (1.3 - 3.8% and fat (2.8 - 8.6%. This fact opens the possibility of using both initial by-products as ingredients in the food industry, due to the effects associated with the high total dietary fibre content.

  3. Connectorization of fibre Bragg grating sensors recorded in microstructured polymer optical fibre

    DEFF Research Database (Denmark)

    Abang, A.; Saez-Rodriguez, D.; Nielsen, Kristian

    2013-01-01

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

  4. Applying elastic fibre biology in vascular tissue engineering.

    Science.gov (United States)

    Kielty, Cay M; Stephan, Simon; Sherratt, Michael J; Williamson, Matthew; Shuttleworth, C Adrian

    2007-08-29

    For the treatment of vascular disease, the major cause of death in Western society, there is an urgent need for tissue-engineered, biocompatible, small calibre artery substitutes that restore biological function. Vascular tissue engineering of such grafts involves the development of compliant synthetic or biomaterial scaffolds that incorporate vascular cells and extracellular matrix. Elastic fibres are major structural elements of arterial walls that can enhance vascular graft design and patency. In blood vessels, they endow vessels with the critical property of elastic recoil. They also influence vascular cell behaviour through direct interactions and by regulating growth factor activation. This review addresses physiological elastic fibre assembly and contributions to vessel structure and function, and how elastic fibre biology is now being exploited in small diameter vascular graft design.

  5. Prolonging contact lens wear and making contact lens wear safer.

    Science.gov (United States)

    Foulks, Gary N

    2006-02-01

    To summarize the present status of safety and efficacy of contact lens wear. Literature review. Ovid Medline searches were performed on records from 1966 through 2005 using keywords: keratitis, contact lens complications, extended-wear contact lenses, and silicone-hydrogel contact lenses. Patients desire comfort, clarity of vision, and prolonged contact lens wear when contact lenses are used to correct refractive error. Practitioners desire patient satisfaction but also require maintenance of the integrity of the eye and no complications that jeopardize vision or health of the eye. Improvements in the oxygen permeability of the contact lens materials, design of the contact lens and its surface, and solutions for the maintenance of the lens have reduced but not eliminated the risks of infection, inflammation, and conjunctival papillary reaction associated with contact lens wear. The lessons of past and recent history suggest that patient education and practitioner participation in the management of contact lens wear continue to be critical factors for patient satisfaction and safety in the extended wear of contact lenses. The availability of highly oxygen permeable contact lenses has increased the tolerance and safety of extended contact lens wear, but patient instruction and education in proper use and care of lenses is required and caution is advised.

  6. Corneal ring infiltration in contact lens wearers

    Directory of Open Access Journals (Sweden)

    Seyed Ali Tabatabaei

    2017-01-01

    Full Text Available To report a case of atypical sterile ring infiltrates during wearing soft silicone hydrogel contact lens due to poor lens care. A 29-year-old woman presented with complaints of pain, redness, and morning discharge. She was wearing soft silicone hydrogel contact lens previously; her current symptoms began 1 week before presentation. On examination, best-corrected visual acuity was 20/40 in that eye. Slit-lamp examination revealed dense, ring-shaped infiltrate involving both the superficial and deep stromal layers with lucid interval to the limbus, edema of the epithelium, epithelial defect, and vascularization of the superior limbus. Cornea-specific in vivo laser confocal microscopy (Heidelberg Retina Tomograph 2 Rostock Cornea Module, HRT 2-RCM, Heidelberg Engineering GmbH, Dossenheim, Germany revealed Langerhans cells and no sign of Acanthamoeba or fungal features, using lid scraping and anti-inflammatory drops; her vision completely recovered. We reported an atypical case of a sterile corneal ring infiltrate associated with soft contact lens wearing; smear, culture, and confocal microscopy confirmed a sterile inflammatory reaction.

  7. Tonic fibres in axial muscle of cyprinid fish larvae: their definition, possible origins and functional importance.

    Science.gov (United States)

    Stoiber, W; Haslett, J R; Steinbacher, P; Freimüller, M; Sänger, A M

    2002-05-01

    Teleost fish are known to develop small populations of muscle fibres that are assumed to be tonic in nature although their contractile properties and many other characteristics remain unknown. Here we attempt to resolve some of the ambiguity and confusions surrounding the definition and functional role of tonic fibres in teleosts and provide new information on their ontogeny. We investigate the differentiation of tonic muscle fibres in three species of cyprinid fish using electron microscopy, histochemistry, immunohistochemistry and in situ hybridization. The fine structure of the fibres defined as tonic in the larvae used in this study complies with patterns known from studies in teleost adults. This allows formal definition of tonic fibres in cyprinid larvae. The tonic fibres may be recognized by a variety of features: (1) by their characteristic position along the medial confines of the red muscle insertion at the horizontal septum, (2) their fine structure, including solid clusters of irregularly cleaved myofibrils, thick and wavy Z-lines, and T-tubules at the A-band/I-band transitions, (3) their histochemical features, specifically weak but obvious staining for mATPase after alkaline preincubation, and lack of SDH activity in the more advanced larval stages, (4) their unique immunological properties, being the only fibre type in the myotome that reacts with a serum against chicken tonic myosin (anti- T2). Expression of tonic characters usually begins within a few fibres in the dorsal domain of the superficial red muscle insertion at the horizontal septum and hence involves a high degree of dorso-ventral polarity. The present evidence indicates that tonic fibres arise from separate myogenic stem cells rather than by transdifferentiation from existing red fibres. First appearance of tonic fibres during ontogeny correlates closely with the onset of free swimming and exogeneous feeding. We use this fact to argue that tonic fibres are probably a prerequisite for

  8. Carbon nanotubes for ultrafast fibre lasers

    Directory of Open Access Journals (Sweden)

    Chernysheva Maria

    2016-06-01

    Full Text Available Carbon nanotubes (CNTs possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA, their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb, bismuth (Bi, erbium (Er, thulium (Tm and holmium (Ho-doped fibre lasers.

  9. Practical Hydrogen Loading of Air Silica Fibres

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Jensen, Jesper Bevensee; Jensen, Jesper Bo Damm

    2005-01-01

    A method for hydrogen-loading air-silica optical fibres has been developed allowing out-diffusion times comparable to standard step-index fibres. Examples of the first grating written in Ge-doped air-silica fibres using a 266nm UV-laser are shown.......A method for hydrogen-loading air-silica optical fibres has been developed allowing out-diffusion times comparable to standard step-index fibres. Examples of the first grating written in Ge-doped air-silica fibres using a 266nm UV-laser are shown....

  10. Kinetic measurements on bacterial cultures growing on fibres

    African Journals Online (AJOL)

    of solubilization of the substrate under defined environmental conditions. Preliminary results of kinetic measurements on ... the effect of environmental factors such as pH on the growth rates. The reason for this is the difficulty in .... with the great majority of cells attached to fibres. Notwithstanding reports about the fragility of.

  11. Dietary Fibres: Their Analysis in Animal Feeding, and Their Role in Rabbit Nutrition and Health

    Directory of Open Access Journals (Sweden)

    Thierry Gidenne

    2013-12-01

    Full Text Available Two centuries ago Heinrich Einhof developed the so-called Weende method (crude fibre, to first deals with the fibre content of the feeds for ruminants, and proposes to isolate a residue called the "crude fibre". Then, dietary fibre concepts evolve and differ in animal feeding compared to human nutrition and health. Animal nutritionists deal with various fibre sources, often from whole plants (forages, by products of seeds processing, and recover a larger range of polysaccharidic components, including other polymers, such polyphenolic (lignins, tannins or polylipidic compounds (cutins. Dietary fibres are generally defined as polysaccharides and associated substances resistant to mammal enzyme digestion and absorption that can be partially or totally fermented in the gut. However, today this topic is still subjected to very active research, because of the complexity of the physical structure and chemical composition of the plant cell walls, and in the wide and different physiological effects of these different constituents. The importance of dietary fibre in animal feeding is due to its influence on rate of passage, mucosa functionality and its role as substrate for gut microbes performances and digestive health. This review will describe the definition and different structure of fibres and cell wall constituents and their analytical methods.

  12. Crystallization of the C-terminal head domain of the avian adenovirus CELO long fibre

    Energy Technology Data Exchange (ETDEWEB)

    Guardado Calvo, Pablo [Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Sur, E-15782 Santiago de Compostela (Spain); Llamas-Saiz, Antonio L. [Unidad de Difracción de Rayos X, Laboratorio Integral de Dinámica y Estructura de Biomoléculas José R. Carracido, Edificio CACTUS, Universidad de Santiago de Compostela, Campus Sur, E-15782 Santiago de Compostela (Spain); Langlois, Patrick [Agence Francaise de Securité Sanitaire des Aliments, Unité Génétique Virale et Biosecurité, Site Les Croix, BP 53, F-22440 Ploufragan (France); Raaij, Mark J. van, E-mail: vanraaij@usc.es [Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Sur, E-15782 Santiago de Compostela (Spain); Unidad de Difracción de Rayos X, Laboratorio Integral de Dinámica y Estructura de Biomoléculas José R. Carracido, Edificio CACTUS, Universidad de Santiago de Compostela, Campus Sur, E-15782 Santiago de Compostela (Spain)

    2006-05-01

    Avian adenovirus long-fibre head trimers were expressed, purified and crystallized. The crystals belong to space group C2 (unit-cell parameters a = 216.5, b = 59.2, c = 57.5 Å, β = 101.3°). A complete highly redundant data set was collected to 2.2 Å resolution at 100 K using a rotating-anode X-ray source. Avian adenovirus CELO contains two different fibres: fibre 1, the long fibre, and fibre 2, the short fibre. The short fibre is responsible for binding to an unknown avian receptor and is essential for infection of birds. The long fibre is not essential, but is known to bind the coxsackievirus and adenovirus receptor protein. Both trimeric fibres are attached to the same penton base, of which each icosahedral virus contains 12 copies. The short fibre extends straight outwards, while the long fibre emerges at an angle. The carboxy-terminal amino acids 579–793 of the avian adenovirus long fibre have been expressed with an amino-terminal hexahistidine tag and the expressed trimeric protein has been purified by nickel-affinity chromatography and crystallized. Crystals were grown at low pH using PEG 10 000 as precipitant and belonged to space group C2. The crystals diffracted rotating-anode Cu Kα radiation to at least 1.9 Å resolution and a complete data set was collected from a single crystal to 2.2 Å resolution. Unit-cell parameters were a = 216.5, b = 59.2, c = 57.5 Å, β = 101.3°, suggesting one trimer per asymmetric unit and a solvent content of 46%. The long fibre head does not have significant sequence homology to any other protein of known structure and molecular-replacement attempts with known fibre-head structures were unsuccessful. However, a map calculated using SIRAS phasing shows a clear trimer with a shape similar to known adenovirus fibre-head structures. Structure solution is in progress.

  13. Compliance among soft contact lens wearers.

    OpenAIRE

    Kuzman, Tomislav; Barišić Kutija, Marija; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurišić, Darija; Škegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-01-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in ...

  14. Drop on a bent fibre.

    Science.gov (United States)

    Pan, Zhao; Weyer, Floriane; Pitt, William G; Vandewalle, Nicolas; Truscott, Tadd T

    2018-03-15

    Inspired by the huge droplets attached on cypress tree leaf tips after rain, we find that a bent fibre can hold significantly more water in the corner than a horizontally placed fibre (typically up to three times or more). The maximum volume of the liquid that can be trapped is remarkably affected by the bending angle of the fibre and surface tension of the liquid. We experimentally find the optimal included angle (∼36°) that holds the most water. Analytical and semi-empirical models are developed to explain these counter-intuitive experimental observations and predict the optimal angle. The data and models could be useful for designing microfluidic and fog harvesting devices.

  15. Carbon fibre material for tomorrow

    International Nuclear Information System (INIS)

    Kartini Noorsal; Mohd Ariff Baharom

    2010-01-01

    As science and technology continue to cross boundaries of known practices, materials and manufacturing techniques and into the frontiers of new materials, environment and applications, the opportunities for research in materials in general will inevitably increase. The unique properties of carbon fibre which combines low weight and high stiffness, makes it in ever greater demand as substitutes for traditional materials. This is due to the rising costs of raw materials and energy and the necessity to reduce carbon dioxide emission. The carbon fibres produced are particularly of high standard in terms of quality and processing characteristics especially when it is designed in structural components in the aerospace and defence industries. This results in a well structured organisation in producing the fibre starting from its raw material to the final composite products. In achieving this effort, research and communication of the progress takes a fundamental role. (author)

  16. LHCb Upgrade: Scintillating Fibre Tracker

    International Nuclear Information System (INIS)

    Tobin, Mark

    2016-01-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  17. Fibre Optics In Coal Mining

    Science.gov (United States)

    Cooper, Paul

    1984-08-01

    Coal mines have a number of unique problems which affect the use of fibre optic technology. These include a potentially explosive atmosphere due to the evolution of methane from coal, and a dirty environment with no cleaning facilities readily available. Equipment being developed by MRDE to allow the exploitation of optical fibres underground includes: A hybrid electrical/fibre optic connector for the flexible power trailing cable of the coal-face shearer; An Intrinsically Safe (IS) pulsed laser transmitter using Frequency Shift Key (FSK) data modulation; An IS Avalanche Photo Diode Receiver suitable for pulsed & continuous wave optical signals; A mine shaft and roadway cable/ connector system incorporating low loss butt-splices and preterminated demountable connectors.

  18. Panoramic lens applications revisited

    Science.gov (United States)

    Thibault, Simon

    2008-04-01

    During the last few years, innovative optical design strategies to generate and control image mapping have been successful in producing high-resolution digital imagers and projectors. This new generation of panoramic lenses includes catadioptric panoramic lenses, panoramic annular lenses, visible/IR fisheye lenses, anamorphic wide-angle attachments, and visible/IR panomorph lenses. Given that a wide-angle lens images a large field of view on a limited number of pixels, a systematic pixel-to-angle mapping will help the efficient use of each pixel in the field of view. In this paper, we present several modern applications of these modern types of hemispheric lenses. Recently, surveillance and security applications have been proposed and published in Security and Defence symposium. However, modern hemispheric lens can be used in many other fields. A panoramic imaging sensor contributes most to the perception of the world. Panoramic lenses are now ready to be deployed in many optical solutions. Covered applications include, but are not limited to medical imaging (endoscope, rigiscope, fiberscope...), remote sensing (pipe inspection, crime scene investigation, archeology...), multimedia (hemispheric projector, panoramic image...). Modern panoramic technologies allow simple and efficient digital image processing and the use of standard image analysis features (motion estimation, segmentation, object tracking, pattern recognition) in the complete 360° hemispheric area.

  19. Development of hemp fibre - PP nonwoven composites

    CSIR Research Space (South Africa)

    Hargitai, H

    2006-01-01

    Full Text Available Nonwoven mats from hemp and polypropylene fibres in various proportions were produced and hot pressed to make composite material. The effect of hemp fibre content and anisotropy in nonwoven mats resulting from the carding technology were examined...

  20. Hollow Core Photonic Crystal Fibre Comprising a Fibre Grating in the Cladding and its Applications

    DEFF Research Database (Denmark)

    2010-01-01

    An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction.......An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction....

  1. The Influence of Fibre Content on the Performance of Steel Fibre ...

    African Journals Online (AJOL)

    Steel fibres are commonly used in the refractory industry to reinforce high temperature concretes. Little information is available on the effect of fibre content on refractory performance and in particular resistance to thermal shock. This study has examined the influence of fibre content of stainless steel melt extract fibres on the ...

  2. Fibre reinforced concrete in flexure and single fibre pull-out test: a correlation

    Science.gov (United States)

    Manca, M.; Ciancio, D.; Dight, P.

    2017-09-01

    The aim of the present work is to assess whether a single fibre pull-out test can be related to the behaviour of multiple fibres in fibre reinforced concrete under bending condition. A simple model based on the stress block theory is described and compared with experimental results on three point bending tests with aligned fibres.

  3. Methodology for characterisation of glass fibre composite architecture

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Larsen, J.B.; Østergaard, R.C.

    2012-01-01

    of the fibres. The information is used for different analyses to investigate and characterise the fibre architecture. As an example, the methodology is applied to glass fibre reinforced composites with varying fibre contents. The different fibre volume fractions (FVFs) affect the number of contact points per...... fibre architecture and composite properties....

  4. Macrophages and nerve fibres in peritoneal endometriosis.

    Science.gov (United States)

    Tran, Lu Vinh Phuc; Tokushige, Natsuko; Berbic, Marina; Markham, Robert; Fraser, Ian S

    2009-04-01

    Endometriosis is considered to be an inflammatory disease, and macrophages are the most numerous immune cells in endometriotic lesions. However, the mechanisms underlying the elevation of macrophages and their role in the pathogenesis and manifestations of endometriosis still remain unclear. The number of macrophages stained for CD68 in endometriotic lesions (n = 24) and in peritoneum distant from the lesions (n = 14) from women with endometriosis was compared with the number of macrophages in normal peritoneum from women without endometriosis (n = 18). Peritoneal lesions were also double-stained for CD68 and protein gene product 9.5 to study the relationship between macrophages and nerve fibres. The densities of macrophages in peritoneal endometriotic lesions and unaffected peritoneum from women with endometriosis were both significantly higher than that in normal peritoneum from women without endometriosis (P peritoneal lesions from women with endometriosis compared with normal peritoneum from women without endometriosis. These cells may well play roles in the growth and development of endometriotic lesions and in the generation of pain through interaction with nerve fibres.

  5. Anatomy and lignin distribution in reaction phloem fibres of several Japanese hardwoods.

    Science.gov (United States)

    Nakagawa, Kaori; Yoshinaga, Arata; Takabe, Keiji

    2012-09-01

    Although tension wood formation and the structure of gelatinous fibres (G-fibres) have been widely investigated, studies of the influence of the reaction phenomenon on phloem fibres have been few and incomplete in comparison with those of xylem wood fibres. This study was undertaken to clarify the influence of stem inclination on phloem fibres using several Japanese hardwood species that produce different G-fibre types in tension wood. Eight hardwood species were inclined at 30-45° at the beginning of April. Specimens were collected in July and December. The cell-wall structure and lignin distribution of phloem fibres on both the tension and opposite sides were compared by light microscopy, ultraviolet microscopy, confocal laser scanning microscopy after staining with acriflavine, and transmission electron microscopy after staining with potassium permanganate. Three types of changes were found in tension-side phloem fibres: (1) increases in the proportion of the syringyl unit in lignin in the S(1) and S(2) layers and compound middle lamella (Cercidiphyllum japonicum), (2) formation of unlignified gelatinous layers (Melia azedarach and Acer rufinerve) and (3) increases in the number of layers (n) in the multi-layered structure of S(1) + S(2) + n (G + L) (Mallotus japonicus). Other species showed no obvious change in cell-wall structure or lignin distribution. Phloem fibres of the tree species examined in our study showed three types of changes in lignin distribution and cell-wall structure. The reaction phenomenon may vary with tree species and may not be closely related to G-fibre type in tension wood.

  6. Photonic crystal fibres and effective index approaches

    DEFF Research Database (Denmark)

    Riishede, Jesper; Libori, Stig E. Barkou; Bjarklev, Anders Overgaard

    2001-01-01

    Photonic crystal fibres are investigated with an effective index approach. The effective index of both core and cladding is found to be wavelength dependent. Accurate modelling must respect the rich topology of these fibres.......Photonic crystal fibres are investigated with an effective index approach. The effective index of both core and cladding is found to be wavelength dependent. Accurate modelling must respect the rich topology of these fibres....

  7. Local fibred right adjoints are polynomial

    DEFF Research Database (Denmark)

    Kock, Anders; Kock, Joachim

    2013-01-01

    For any locally cartesian closed category E, we prove that a local fibred right adjoint between slices of E is given by a polynomial. The slices in question are taken in a well known fibred sense......For any locally cartesian closed category E, we prove that a local fibred right adjoint between slices of E is given by a polynomial. The slices in question are taken in a well known fibred sense...

  8. Fibre Optic Communication Key Devices

    CERN Document Server

    Grote, Norbert

    2012-01-01

    The book gives an in-depth description of the key devices of current and next generation fibre optic communication networks. In particular, the book covers devices such as semiconductor lasers, optical amplifiers, modulators, wavelength filters, and detectors but the relevant properties of optical fibres as well. The presentations include the physical principles underlying the various devices, the technologies used for the realization of the different devices, typical performance characteristics and limitations, and development trends towards more advanced components are also illustrated. Thus the scope of the book spans relevant principles, state-of-the-art implementations, the status of current research and expected future components.

  9. Carbon Fibres from Kraft Lignin

    OpenAIRE

    Norberg, Ida

    2012-01-01

    Kraft lignin has a high potential for use in more valuable applications than its current use as fuel in pulp mills and integrated pulp and paper mills. The possibility of using kraft lignin, a green material with a carbon content of more than 60 %, for the manufacturing of carbon fibres was investigated in this thesis. The strong and lightweight carbon fibre material has many potential application areas, e.g. in cars; the main obstacle limiting its demand is the high production cost, with the...

  10. Active textiles with Janus fibres

    Science.gov (United States)

    Zakharov, A. P.; Pismen, L. M.

    We describe reshaping of active textiles actuated by bending of Janus fibres comprising both active and passive components. A great variety of shapes, determined by minimising the overall energy of the fabric, can be produced by varying bending directions determined by the orientation of Janus fibres. Under certain conditions, alternative equilibrium states, one absolutely stable and the other metastable coexist, and their relative energy may flip its sign as system parameters, such as the extension upon actuation, change. A snap-through reshaping in a specially structured textile reproduces the Venus flytrap effect.

  11. Protective Effect of D-Limonene against Oxidative Stress-Induced Cell Damage in Human Lens Epithelial Cells via the p38 Pathway.

    Science.gov (United States)

    Bai, Jie; Zheng, Yi; Wang, Gang; Liu, Ping

    2016-01-01

    Oxidative stress, as mediated by ROS, is a significant factor in initiating the development of age-associated cataracts; D-limonene is a common natural terpene with powerful antioxidative properties which occurs naturally in a wide variety of living organisms. It has been shown to have antioxidant effect; we found that D-limonene can effectively prevent the oxidative damage caused by H2O2 and propose that the main mechanism underlying the inhibitory effects of D-limonene is the inhibition of HLECs apoptosis. In the present study, we used confocal-fluorescence microscopy, flow cytometry analysis, Hoechst staining, H2DCFDA staining, transmission electron microscopy, and immunoblot analysis; the results revealed that slightly higher concentrations of D-limonene (125-1800 μM) reduced the H2O2-induced ROS generation and inhibited the H2O2-induced caspase-3 and caspase-9 activation and decreased the Bcl-2/Bax ratio. Furthermore, it inhibited H2O2-induced p38 MAPK phosphorylation. Thus, we conclude that D-limonene could effectively protect HLECs from H2O2-induced oxidative stress and that its antioxidative effect is significant, thereby increasing the cell survival rate.

  12. Mohair, cashmere and other animal hair fibres

    CSIR Research Space (South Africa)

    Hunter, L

    2012-11-01

    Full Text Available animal hair fibres L Hunter, CSIR and Nelson Mandela Metropolitan University (NMMU), South Africa Although luxury animal fibres, excluding silk, represent far less than 0.1% of global fibre production, they play a very significant role in the luxury...

  13. Continuous jute fibre reinforced laminated paper composite

    Indian Academy of Sciences (India)

    Plastic bags create a serious environmental problem. The proposed jute fibre reinforced laminated paper composite and reinforcement-fibre free paper laminate may help to combat the war against this pollutant to certain extent. The paper laminate, without reinforcement fibre, exhibited a few fold superiority in tensile ...

  14. Stress concentrations in an impregnated fibre bundle with random fibre packing

    OpenAIRE

    Swolfs, Y.; Gorbatikh, L.; Romanov, V.; Orlova, S.; Lomov, S. V.; Verpoest, I.

    2013-01-01

    The stress redistribution after a single fibre break is a fundamental issue in longitudinal strength models for unidirectional composites. Current models assume hexagonal or square fibre packings. In the present work, random fibre packings were modelled using 3D finite element analysis and compared to ordered fibre packings. Significant differences in the stress redistribution are found. Compared to square and hexagonal packings, random fibre packings result in smaller stress concentration fa...

  15. Mechanical processing of bast fibres: The occurrence of damage and its effect on fibre structure

    DEFF Research Database (Denmark)

    Hänninen, Tuomas; Thygesen, Anders; Mehmood, Shahid

    2012-01-01

    Currently, separation processes used for natural fibres for composite reinforcing textiles cause a significant amount of damage to the fibres. Microscopic analysis showed that industrially processed flax (Linum usitassimium L.) fibres contained significantly more defects than green or retted ones...... to heterogeneous reactivity. Analogous findings were observed in hemp (Cannabis sativa L.) fibre damaged in the laboratory under controlled conditions, emphasising the need to develop extraction and separation processes that minimise mechanical damage to the fibres....

  16. VARIABILITY STUDIES ON STRENGTH AND FIBRE PROPERTIES OF Bambusa vulgaris Schrad. FOR PANEL PRODUCTS

    Directory of Open Access Journals (Sweden)

    Kehinde Sesan AINA

    2012-03-01

    Full Text Available A variability study on strength and fibre properties of bamboo (Bambusa vulgaris was investigated in this study. Bamboo bole length of two geographical locations (Ibadan and Ilorin at percentage of (10, 30, 50, 70 and 90 were used to determine the fibre properties such as fibre length, fibre diameter, lumen width, cell wall thickness, runkel ratio, flexibility coefficient and relative fibre length. The strength properties of bamboolaminated boards were also investigated in this study with the effect of different variable factors, such as the adhesive type (Top bond and Urea formaldehyderide, bole portion (top, middle and base and bole thickness size (5mm x 20mm and 10mm x 20mm. Mechanical properties, such as the modulus of rupture, impact bending strength, compression strength, shear strength in both parallel and perpendicular direction were determined. The results show that there is potential for using bamboo for the production of paper and as building and structural material.

  17. The use of dimethyl sulfoxide in contact lens disinfectants is a potential preventative strategy against contracting Acanthamoeba keratitis.

    Science.gov (United States)

    Siddiqui, Ruqaiyyah; Aqeel, Yousuf; Khan, Naveed Ahmed

    2016-10-01

    Acanthamoeba castellanii is the causative agent of blinding keratitis. Though reported in non-contact lens wearers, it is most frequently associated with improper use of contact lens. For contact lens wearers, amoebae attachment to the lens is a critical first step, followed by amoebae binding to the corneal epithelial cells during extended lens wear. Acanthamoeba attachment to surfaces (biological or inert) and migration is an active process and occurs during the trophozoite stage. Thus retaining amoebae in the cyst stage (dormant form) offers an added preventative measure in impeding parasite traversal from the contact lens onto the cornea. Here, we showed that as low as 3% DMSO, abolished A. castellanii excystation. Based on the findings, it is proposed that DMSO should be included in the contact lens disinfectants as an added preventative strategy against contracting Acanthamoeba keratitis. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2013-04-01

    Wood pulp fibres are an important component of environmentally sound and renewable fibre-reinforced composite materials. The high aspect ratio of pulp fibres is an essential property with respect to the mechanical properties a given composite material can achieve. The length of pulp fibres is affected by composite processing operations. This thus emphasizes the importance of assessing the pulp fibre length and how this may be affected by a given process for manufacturing composites. In this work a new method for measuring the length distribution of fibres and fibre fragments has been developed. The method is based on; (i) dissolving the composites, (ii) preparing the fibres for image acquisition and (iii) image analysis of the resulting fibre structures. The image analysis part is relatively simple to implement and is based on images acquired with a desktop scanner and a new ImageJ plugin. The quantification of fibre length has demonstrated the fibre shortening effect because of an extrusion process and subsequent injection moulding. Fibres with original lengths of >1 mm where shortened to fibre fragments with length of <200 μm. The shortening seems to be affected by the number of times the fibres have passed through the extruder, the amount of chain extender and the fraction of fibres in the polymer matrix. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  19. The Effect of Rotating Collector Design on Tensile Properties and Morphology of Electrospun Polycaprolactone Fibres

    Directory of Open Access Journals (Sweden)

    Anindyajati Adhi

    2015-01-01

    Full Text Available Electrospinning is a technique that can produce fibres in the nanoscale range. This process is useful for many applications, including fabrication of fibrous scaffolds for fibrocartilage tissue engineering. For this application, cell attachment and tissue development is influenced by fibre morphology and mechanical properties. This electrospinning study investigated the influence of rotating collector design on morphology and mechanical properties of electrospun polycaprolactone fibre. The experiment employed 4 mandrel designs: 1 full surface of aluminium; 2 with gap feature; 3 with gap feature and teflon support; 4 with gap feature and tape support. The highest elastic modulus was obtained from mandrel with gap and tape support, which was 24.6 MPa and significantly higher compared to fibres acquired from other collector designs. Fibre diameter attained was identical across the different collectors, ranging from 0.5 - 2 μm. Gap introduction showed enhanced alignment in the resultant fibre. It can be concluded that fibre alignment and tensile properties can be improved by simply modifying the collector design. This improved fibre mat can be developed as a biomaterial for fibrocartilage tissue engineering scaffolds.

  20. Particle and Fibre Toxicology, a new journal to meet a real need

    Directory of Open Access Journals (Sweden)

    Borm Paul

    2004-12-01

    Full Text Available Abstract This Editorial is to announce Particle and Fibre Toxicology, a new Open Access, peer-reviewed, online journal published by BioMed Central. The field of particle and fibre toxicology has a long and famous history stretching from Agricola and Paracelsus in the 15th and 16th century to the challenges of the 21st century-nanoparticles, nanotubes and particulate matter (PM10 to name just three. Throughout this time there has been no single journal dedicated to the toxicology of particles and fibres and this is finally corrected by the launch of Particle and Fibre Toxicology. The rationale for Particle and Fibre Toxicology rests on this need for a single multi-disciplinary journal that can cover all research relevant to particle and fibre toxicology, from Hygiene studies, through particle generation and characterisation, to animal, cell and human toxicology studies, dosimetry and modelling. The editorial also deals with the philosophy and practicalities of Open Access publishing, the journal's peer-review policy and conflict-of-interest. Particle and Fibre Toxicology is aimed at bringing together multi-disciplinary research findings towards a better understanding of how particles and fibres adversely affect the lungs and the body generally. We hope that the launch of the new journal will aid in the advance of this important discipline to the greater benefit of occupational and public health and invite scientists working in this key discipline to submit their research.

  1. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

  2. Cool application for Optical Fibres

    CERN Multimedia

    2001-01-01

    In a new first for CERN, optical fibres have been put on test to measure very low temperatures. If these tests prove successful, this new technology could lead to important cost-saving changes in the way the temperatures of superconducting magnets are measured. There was excitement in the air last March when the team led by Walter Scandale and Luc Thévenaz tested very low temperature measurement using optical fibres. This spring in CERN's Cryogenics lab an idea was put to the test as a new kind of low-temperature thermometry using optical fibres was tested down to 2 Kelvin (around 300 degrees below room temperature), and the first results are looking good. Optical fibres are well known for their ability to carry large amounts of data around the world, but it is less well known that they can be used for measuring temperatures. The intuition that they might be able to measure very low temperatures - such as those of the LHC magnets - came to the attention of CERN's Walter Scandale at the Optical Fi...

  3. Flow diagnostics using fibre optics

    Indian Academy of Sciences (India)

    high enthalpy, high speed flows and in combustion chambers, rocket exhausts etc. 3. Aerodynamic load measurements at hypersonic speeds using internally mounted fibre-optic balance system. 3.1 The IISc hypersonic wind tunnel. The IISc hypersonic wind tunnel is of the pressure-vacuum type with an open jet test section.

  4. Ibuprofen-loaded poly(trimethylene carbonate-co-ε-caprolactone) electrospun fibres for nerve regeneration.

    Science.gov (United States)

    Pires, Liliana R; Guarino, Vincenzo; Oliveira, Maria J; Ribeiro, Cristina C; Barbosa, Mário A; Ambrosio, Luigi; Pêgo, Ana Paula

    2016-03-01

    The development of scaffolds that combine the delivery of drugs with the physical support provided by electrospun fibres holds great potential in the field of nerve regeneration. Here it is proposed the incorporation of ibuprofen, a well-known non-steroidal anti-inflammatory drug, in electrospun fibres of the statistical copolymer poly(trimethylene carbonate-co-ε-caprolactone) [P(TMC-CL)] to serve as a drug delivery system to enhance axonal regeneration in the context of a spinal cord lesion, by limiting the inflammatory response. P(TMC-CL) fibres were electrospun from mixtures of dichloromethane (DCM) and dimethylformamide (DMF). The solvent mixture applied influenced fibre morphology, as well as mean fibre diameter, which decreased as the DMF content in solution increased. Ibuprofen-loaded fibres were prepared from P(TMC-CL) solutions containing 5% ibuprofen (w/w of polymer). Increasing drug content to 10% led to jet instability, resulting in the formation of a less homogeneous fibrous mesh. Under the optimized conditions, drug-loading efficiency was above 80%. Confocal Raman mapping showed no preferential distribution of ibuprofen in P(TMC-CL) fibres. Under physiological conditions ibuprofen was released in 24 h. The release process being diffusion-dependent for fibres prepared from DCM solutions, in contrast to fibres prepared from DCM-DMF mixtures where burst release occurred. The biological activity of the drug released was demonstrated using human-derived macrophages. The release of prostaglandin E2 to the cell culture medium was reduced when cells were incubated with ibuprofen-loaded P(TMC-CL) fibres, confirming the biological significance of the drug delivery strategy presented. Overall, this study constitutes an important contribution to the design of a P(TMC-CL)-based nerve conduit with anti-inflammatory properties. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Extraction of High Quality RNA from Cannabis sativa Bast Fibres: A Vademecum for Molecular Biologists

    Directory of Open Access Journals (Sweden)

    Gea Guerriero

    2016-07-01

    Full Text Available In plants there is no universal protocol for RNA extraction, since optimizations are required depending on the species, tissues and developmental stages. Some plants/tissues are rich in secondary metabolites or synthesize thick cell walls, which hinder an efficient RNA extraction. One such example is bast fibres, long extraxylary cells characterized by a thick cellulosic cell wall. Given the economic importance of bast fibres, which are used in the textile sector, as well as in biocomposites as green substitutes of glass fibres, it is desirable to better understand their development from a molecular point of view. This knowledge favours the development of biotechnological strategies aimed at improving specific properties of bast fibres. To be able to perform high-throughput analyses, such as, for instance, transcriptomics of bast fibres, RNA extraction is a crucial and limiting step. We here detail a protocol enabling the rapid extraction of high quality RNA from the bast fibres of textile hemp, Cannabis sativa L., a multi-purpose fibre crop standing in the spotlight of research.

  6. Physical limits to biomechanical sensing in disordered fibre networks

    Science.gov (United States)

    Beroz, Farzan; Jawerth, Louise M.; Münster, Stefan; Weitz, David A.; Broedersz, Chase P.; Wingreen, Ned S.

    2017-07-01

    Cells actively probe and respond to the stiffness of their surroundings. Since mechanosensory cells in connective tissue are surrounded by a disordered network of biopolymers, their in vivo mechanical environment can be extremely heterogeneous. Here we investigate how this heterogeneity impacts mechanosensing by modelling the cell as an idealized local stiffness sensor inside a disordered fibre network. For all types of networks we study, including experimentally-imaged collagen and fibrin architectures, we find that measurements applied at different points yield a strikingly broad range of local stiffnesses, spanning roughly two decades. We verify via simulations and scaling arguments that this broad range of local stiffnesses is a generic property of disordered fibre networks. Finally, we show that to obtain optimal, reliable estimates of global tissue stiffness, a cell must adjust its size, shape, and position to integrate multiple stiffness measurements over extended regions of space.

  7. Co-extrusion of electrolyte/anode functional layer/anode triple-layer ceramic hollow fibres for micro-tubular solid oxide fuel cells-electrochemical performance study

    Science.gov (United States)

    Li, Tao; Wu, Zhentao; Li, K.

    2015-01-01

    In this study, the effects of an anode functional layer (AFL) with controlled thickness on physical and electrochemical properties of a micro-tubular SOFC have been systematically studied. A series of electrolyte/AFL/anode triple-layer hollow fibres with controllable AFL thicknesses (16.9-52.7 μm) have been fabricated via a single-step phase-inversion assisted co-extrusion technique. Both robustness of the cell and gas-tightness of the electrolyte layer are considerably improved by introducing the AFL of this type. The fracture force of the sample with the thickest AFL (9.67 N) almost doubles when compared to the electrolyte/anode dual-layer counterpart (5.24 N). Gas-tightness of the electrolyte layer is also considerably increased as AFL contributes to better-matched sintering behaviours between different components. Moreover, the formation of an AFL simultaneously with electrolyte and anode significantly improves the cell performances. The sample with the thinnest AFL (approximately 16.9 μm, 6% of the total anode thickness) leads to a 30% (from 0.89 to 1.21 W cm-2) increase in maximum power density, due to increased triple-phase boundaries (TPB). However, further increase in TPB from a thicker AFL is less effective for improving the cell performance, due to the substantially increased fuel diffusion resistance and subsequently higher concentration polarization. This indicates that the control over the AFL thickness is critically important in avoiding offsetting the benefits of extended TPB and consequently decreased cell performances.

  8. Moisture sorption in naturally coloured cotton fibres

    Science.gov (United States)

    Ceylan, Ö.; De Clerck, K.

    2017-10-01

    Increasing environmental concerns have stimulated an interest in naturally coloured cottons. As many commercial and technical performance aspects of cotton fibres are influenced by their response towards atmospheric humidity, an in-depth research on moisture sorption behaviour of these fibres using dynamic vapour sorption is carried out. Significant differences were observed in sorption capacity and hysteresis behaviour of brown and green cotton fibres. These differences are mainly attributed to the variations in maturity and crystallinity index of the fibres. This study provides valuable insights into the moisture sorption behaviour of naturally coloured cotton fibres.

  9. Laser–fibre vibrometry at 1550 nm

    International Nuclear Information System (INIS)

    Waz, A T; Kaczmarek, P R; Abramski, K M

    2009-01-01

    This paper presents new solutions for laser vibrometry, which are based on fibre vibrometry in the third telecommunication window. The scattered laser beam from a vibrating object is guided by a fibre collimator and coherently detected through heterodyning it with an acousto-optical frequency-shifted reference beam. The concept of measuring vibration parameters from many points of the vibrating object has been inspired by wavelength division multiplexing (WDM) in fibre telecommunications. The N-independent WDM separated 15XX nm fibre-coupled laser diodes (used for optical fibre telecommunications) form a system of sources for multipoint vibration measurement according to the rule 'one wavelength–one point'

  10. Fibre optic power meter calibration uncertainties

    CSIR Research Space (South Africa)

    Nel, M

    2010-06-01

    Full Text Available The method to empirically quantify the effect that flexing (movement) of the fibre has on the output power was determined by connecting an optical fibre to a power meter head and performing controlled movements of the head (displacements and rotations..., and with their optical axes roughly parallel to one another to reduce the effect of fibre flexing when interchanging from one detector head to another. Excessive flexing and moving of the fibre can cause differences in the radiant power emerging from the fibre...

  11. Fibre optic cable in the nuclear industry

    International Nuclear Information System (INIS)

    Roberts, Berwyn

    1987-01-01

    The uses of optical fibre cables to transmit light signals include medical applications and telecommunications. In the nuclear industry the applications include process control and monitoring, conventional datacoms, security fencing and sensors. Time division multiplexing is described and currently available fibre optic multipexers are listed and explained. Single and multimode fibres are mentioned. Fibre optics are also used in cryogenics, to monitor the integrity of the storage vessels for cryogenic liquids. The uses of fibre optics at Hartlepool, Heysham I and Torness are mentioned in particular. (UK)

  12. Some topological properties of the Inverse Lens Mapping

    Energy Technology Data Exchange (ETDEWEB)

    Mediavilla, T; Ariza, O [Departamento de Estadistica e Investigacion Operativa, Universidad de Cadiz, Avda de Ramon Puyol, s/n 11202 Algeciras (Spain); Mediavilla, E; Oscoz, A [Instituto de Astrofisica de Canarias, Avda Via Lactea s/n, La Laguna (Spain); Munoz, J A, E-mail: teresa.mediavilla@ca.uca.es, E-mail: octavio.ariza@uca.es, E-mail: emg@iac.es, E-mail: jmunoz@uv.es, E-mail: aoscoz@iac.es [Departamento de Astronomia y Astrofisica, Universidad de Valencia, c/ Dr. Moliner, 50, 46100 Burjassot (Spain)

    2011-09-22

    Away from critical curves, lens mapping can be seen as a linear invertible transformation of the plane even for regions (cells) of relatively large size. However, close to critical curves the departures from linearity can be very strong. We discuss the topological problems induced by the mapping of regions of the image plane that include critical curves (critical cells).

  13. Elastic fibres in health and disease.

    Science.gov (United States)

    Baldwin, Andrew K; Simpson, Andreja; Steer, Ruth; Cain, Stuart A; Kielty, Cay M

    2013-08-20

    Elastic fibres are insoluble components of the extracellular matrix of dynamic connective tissues such as skin, arteries, lungs and ligaments. They are laid down during development, and comprise a cross-linked elastin core within a template of fibrillin-based microfibrils. Their function is to endow tissues with the property of elastic recoil, and they also regulate the bioavailability of transforming growth factor β. Severe heritable elastic fibre diseases are caused by mutations in elastic fibre components; for example, mutations in elastin cause supravalvular aortic stenosis and autosomal dominant cutis laxa, mutations in fibrillin-1 cause Marfan syndrome and Weill-Marchesani syndrome, and mutations in fibulins-4 and -5 cause autosomal recessive cutis laxa. Acquired elastic fibre defects include dermal elastosis, whereas inflammatory damage to fibres contributes to pathologies such as pulmonary emphysema and vascular disease. This review outlines the latest understanding of the composition and assembly of elastic fibres, and describes elastic fibre diseases and current therapeutic approaches.

  14. Plant fibre composites - porosity and volumetric interaction

    DEFF Research Database (Denmark)

    Madsen, Bo; Thygesen, Anders; Lilholt, Hans

    2007-01-01

    the combination of a high fibre volume fraction, a low porosity and a high composite density is optimal. Experimental data from the literature on volumetric composition and density of four types of plant fibre composites are used to validate the model. It is demonstrated that the model provides a concept......Plant fibre composites contain typically a relative large amount of porosity, which considerably influences properties and performance of the composites. The large porosity must be integrated in the conversion of weight fractions into volume fractions of the fibre and matrix parts. A model...... is presented to predict the porosity as a function of the fibre weight fractions, and to calculate the related fibre and matrix volume fractions, as well as the density of the composite. The model predicts two cases of composite volumetric interaction separated by a transition fibre weight fraction, at which...

  15. Contact Lens Wear at Altitude: Subcontact Lens Bubble Formation

    Science.gov (United States)

    1987-11-01

    incidence of (PMMA) lenses . Reported here are the results of contact lens subcontact lens bubble formation under scleral lenses at bubble studies with soft...vision from formation of large bubbles greater than 6,096 m (20,000 It). With soft contact lenses , bubble under their contact lenses . They also found...always located at the limbus and were without sequela to vision or corneal epithelial integrity. scleral lenses used by Jaeckle were permeable to gases

  16. Straylight Measurements in Contact Lens Wear

    NARCIS (Netherlands)

    van der Meulen, Ivanka J. E.; Engelbrecht, Leonore A.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Mourits, Maarten P.; Schlingemann, Reinier O.; van den Berg, Thomas J. T. P.

    2010-01-01

    Purpose: (1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints. Methods: Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens

  17. Spatial distribution of glycerophospholipids in the ocular lens.

    Directory of Open Access Journals (Sweden)

    Jaroslav Pól

    Full Text Available Knowledge of the spatial distribution of lipids in the intraocular lens is important for understanding the physiology and biochemistry of this unique tissue and for gaining a better insight into the mechanisms underlying diseases of the lens. Following our previous study showing the spatial distribution of sphingolipids in the porcine lens, the current study used ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS to provide the whole lipidome of porcine lens and these studies were supplemented by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI of the lens using ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS to determine the spatial distribution of glycerophospholipids. Altogether 172 lipid species were identified with high confidence and their concentration was determined. Sphingomyelins, phosphatidylcholines, and phosphatidylethanolamines were the most abundant lipid classes. We then determined the spatial and concentration-dependent distributions of 20 phosphatidylcholines, 6 phosphatidylethanolamines, and 4 phosphatidic acids. Based on the planar molecular images of the lipids, we report the organization of fiber cell membranes within the ocular lens and suggest roles for these lipids in normal and diseased lenses.

  18. Fibre cables in the lacunae of Typha leaves contribute to a tensegrity structure.

    Science.gov (United States)

    Witztum, Allan; Wayne, Randy

    2014-04-01

    Cables composed of long, non-lignified fibre cells enclosed in a cover of much shorter thin-walled, crystal-containing cells traverse the air chambers (lacunae) in leaves of the taller species of Typha. The non-lignified fibre cables are anchored in diaphragms composed of stellate cells of aerenchyma tissue that segment the long air chambers into smaller compartments. Although the fibre cables are easily observed and can be pulled free from the porous-to-air diaphragms, their structure and function have been ignored or misinterpreted. Leaves of various species of Typha were dissected and fibre cables were pulled free and observed with a microscope using bright-field and polarizing optics. Maximal tensile strength of freshly removed cables was measured by hanging weights from fibre cables, and Instron analysis was used to produce curves of load versus extension until cables broke. Polarized light microscopy revealed that the cellulose microfibrils that make up the walls of the cable fibres are oriented parallel to the long axis of the fibres. This orientation ensures that the fibre cables are mechanically stiff and strong under tension. Accordingly, the measured stiffness and tensile strength of the fibre cables were in the gigapascal range. In combination with the dorsal and ventral leaf surfaces and partitions that contain lignified fibre bundles and vascular strands that are strong in compression, the very fine fibre cables that are strong under tension form a tensegrity structure. The tensegrity structure creates multiple load paths through which stresses are redistributed throughout the 1-3 m tall upright leaves of Typha angustifolia, T. latifolia, T. × glauca, T. domingensis and T. shuttleworthii. The length of the fibre cables relative to the length of the leaf blades is reduced in the last-formed leaves of flowering individuals. Fibre cables are absent in the shorter leaves of Typha minima and, if present, only extend for a few centimetres from the sheath

  19. Thin wetting film lens-less imaging

    International Nuclear Information System (INIS)

    Allier, C.P.; Poher, V.; Coutard, J.G.; Hiernard, G.; Dinten, J.M.

    2011-01-01

    Lens-less imaging has recently attracted a lot of attention as a compact, easy-to-use method to image or detect biological objects like cells, but failed at detecting micron size objects like bacteria that often do not scatter enough light. In order to detect single bacterium, we have developed a method based on a thin wetting film that produces a micro-lens effect. Compared with previously reported results, a large improvement in signal to noise ratio is obtained due to the presence of a micro-lens on top of each bacterium. In these conditions, standard CMOS sensors are able to detect single bacterium, e.g. E. coli, Bacillus subtilis and Bacillus thuringiensis, with a large signal to noise ratio. This paper presents our sensor optimization to enhance the SNR; improve the detection of sub-micron objects; and increase the imaging FOV, from 4.3 mm 2 to 12 mm 2 to 24 mm 2 , which allows the detection of bacteria contained in 0.5 μl to 4 μl to 10 μl, respectively. (authors)

  20. Tear film evaluation and management in soft contact lens wear: a systematic approach.

    Science.gov (United States)

    Downie, Laura E; Craig, Jennifer P

    2017-09-01

    The human tear film is a highly ordered structure consisting of a thin layer of lipid on the surface and a thicker aqueous-mucin phase, which increases in mucin concentration toward the corneal epithelial cell layer. The health of the tear film and ocular surface influences the likelihood of being able to achieve successful contact lens wear. Contact lens discomfort and dryness are the most frequent reasons why contact lens wearers experience reduced wearing times, which can eventually lead to contact lens discontinuation. Comprehensive clinical assessment of tear film integrity and ocular surface health is therefore essential prior to commencing contact lens wear, to enable the ocular surface environment to be optimised to support lens wear. These parameters should also be evaluated over the course of contact lens wear, in order to identify any aspects requiring clinical management and ensure maintenance of optimal lens-wearing conditions. This review summarises current knowledge relating to the effects of soft contact lens wear on the tear film and ocular surface. It also provides a systematic approach to evaluating tear film and ocular surface integrity, in order to guide the clinical management of tear film anomalies with respect to contact lens wear. © 2017 Optometry Australia.

  1. The influence of electrospun fibre scaffold orientation and nano-hydroxyapatite content on the development of tooth bud stem cells in vitro

    NARCIS (Netherlands)

    Manen, E.H. van; Zhang, W.; Walboomers, X.F.; Vazquez, B.; Yang, F.; Ji, W.; Yu, N.; Spear, D.J.; Jansen, J.A.; Yelick, P.C.

    2014-01-01

    In stem cell-based dental tissue engineering, the goal is to create tooth-like structures using scaffold materials to guide the dental stem cells. In this study, the effect of fiber alignment and hydroxyapatite content in biodegradable electrospun PLGA scaffolds have been investigated. Fiber

  2. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; Agarwal, P

    2010-01-01

    A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are: overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. Th...

  3. A course in lens design

    CERN Document Server

    Velzel, Chris

    2014-01-01

    A Course in Lens Design is an instruction in the design of image-forming optical systems. It teaches how a satisfactory design can be obtained in a straightforward way. Theory is limited to a minimum, and used to support the practical design work. The book introduces geometrical optics, optical instruments and aberrations. It gives a description of the process of lens design and of the strategies used in this process. Half of its content is devoted to the design of sixteen types of lenses, described in detail from beginning to end. This book is different from most other books on lens design because it stresses the importance of the initial phases of the design process: (paraxial) lay-out and (thin-lens) pre-design. The argument for this change of accent is that in these phases much information can be obtained about the properties of the lens to be designed. This information can be used in later phases of the design. This makes A Course in Lens Design a useful self-study book, and a suitable basis for an intro...

  4. Fundamentals of fibre-reinforced soil engineering

    CERN Document Server

    Shukla, Sanjay Kumar

    2017-01-01

    This book is intended to serve as a one-stop reference on fibre-reinforced soils. Over the past 30-35 years, the engineering behaviour of randomly distributed/oriented fibre-reinforced soil, also called simply fibre-reinforced soil, has been investigated in detail by researchers and engineers worldwide. Waste fibres (plastic waste fibres, old tyre fibres, etc.) create disposal and environmental problems. Utilization of such fibres in construction can help resolve these concerns. Research studies and some field applications have shown that the fibres can be utilized in large quantities in geotechnical and civil engineering applications in a cost-effective and environmentally friendly manner. This book covers a complete description of fibres, their effects when included within a soil or other similar materials such as the fly ash, and their field applications. It gives a detailed view of fibre-reinforced soil engineering. The book will be useful to students, professional, and researchers alike, and can also ser...

  5. Fibre reinforced concrete exposed to elevated temperature

    Science.gov (United States)

    Novák, J.; Kohoutková, A.

    2017-09-01

    Although concrete when subject to fire performs very well, its behaviour and properties change dramatically under high temperature due to damaged microstructure and mesostructure. As fibre reinforced concrete (FRC) represents a complex material composed of various components with different response to high temperature, to determine its behaviour and mechanical properties in fire is a demanding task. The presented paper provides a summary of findings on the fire response of fibre FRC. Namely, the information on steel fibre reinforced concrete (SFRC), synthetic fibre reinforced concrete and hybrid (steel + synthetic) fibre reinforced concrete have been gathered from various contributions published up to date. The mechanical properties including the melting point and ignition point of fibres affect significantly the properties of concrete composites with addition of fibres. The combination of steel and synthetic fibres represents a promising alternative how to ensure good toughness of a concrete composite before heating and improve its residual mechanical behaviour and spalling resistance as well as the ductility after heating. While synthetic fibres increase concrete spalling resistance, steel fibres in a concrete mix leads to an improvement in both mechanical properties and resistance to heating effects.

  6. Gabor lens theory

    International Nuclear Information System (INIS)

    Irani, A.A.

    1978-01-01

    The principle of using the space charge of an electron cloud to focus ion beams was first proposed by Gabor. Electrons are to be confined radially by means of an axial magnetic field B/sub z/ and axially by means of externally applied electric fields E/sub z/. An ion beam of charge density n/sub i/ much less than n/sub e/, the electron charge density can then be focused by the radial electric field set up by the electron cloud. The case considered here is that of a hollow cylindrical conductor charged to a potential +V with grounded rings on either side to set up the axial E/sub z/ field. A solenoid wound around the central conductor supplies the B/sub z/ field. Theoretical calculations are carried out for n/sub e/ maximum as a function of B/sub z/ due to radial confinement and V due to axial confinement and the focal length of the Gabor Lens is calculated

  7. Cx43, ZO-1, alpha-catenin and beta-catenin in cataractous lens

    Indian Academy of Sciences (India)

    Specimens of the anterior lens capsule with an attached monolayer of lens epithelial cells (LECs) were obtained from patients (=52) undergoing cataract surgery. Specimens were divided into three groups based on the type of cataract: nuclear cataract, cortical cataract and posterior subcapsular cataract (PSC).

  8. Cx43, ZO-1, alpha-catenin and beta-catenin in cataractous lens ...

    Indian Academy of Sciences (India)

    Specimens of the anterior lens capsule with an attached monolayer of lens epithelial cells (LECs) were obtained from patients (=52) undergoing cataract surgery. Specimens were divided into three groups based on the type of cataract: nuclear cataract, cortical cataract and posterior subcapsular cataract (PSC).

  9. Fibre optic communication key devices

    CERN Document Server

    Grote, Norbert

    2017-01-01

    The book gives an in-depth description of key devices of current and next generation fibre optic communication networks. Devices treated include semiconductor lasers, optical amplifiers, modulators, wavelength filters and other passives, detectors, all-optical switches, but relevant properties of optical fibres and network aspects are included as well. The presentations include the physical principles underlying the various devices, technologies used for their realization, typical performance characteristics and limitations, but development trends towards more advanced components are also illustrated. This new edition of a successful book was expanded and updated extensively. The new edition covers among others lasers for optical communication, optical switches, hybrid integration, monolithic integration and silicon photonics. The main focus is on Indium phosphide-based structures but silicon photonics is included as well. The book covers relevant principles, state-of-the-art implementations, status of curren...

  10. No turnover in lens lipids for the entire human lifespan.

    Science.gov (United States)

    Hughes, Jessica R; Levchenko, Vladimir A; Blanksby, Stephen J; Mitchell, Todd W; Williams, Alan; Truscott, Roger J W

    2015-03-11

    Lipids are critical to cellular function and it is generally accepted that lipid turnover is rapid and dysregulation in turnover results in disease (Dawidowicz 1987; Phillips et al., 2009; Liu et al., 2013). In this study, we present an intriguing counter-example by demonstrating that in the center of the human ocular lens, there is no lipid turnover in fiber cells during the entire human lifespan. This discovery, combined with prior demonstration of pronounced changes in the lens lipid composition over a lifetime (Hughes et al., 2012), suggests that some lipid classes break down in the body over several decades, whereas others are stable. Such substantial changes in lens cell membranes may play a role in the genesis of age-related eye disorders. Whether long-lived lipids are present in other tissues is not yet known, but this may prove to be important in understanding the development of age-related diseases.

  11. Flow diagnostics using fibre optics

    Indian Academy of Sciences (India)

    a finely machined calibration body as shown in figure 10. The entire loading setup was placed under water in a fish tank measuring 3 × 1·5 × 1·25 ft as shown in figure 11. Prede- termined loads were applied to the balance and the resulting calibration curves are shown in figure 12a & b. The fibre-optic processor was set at ...

  12. Standard Fibre Optic Ring LANs

    Science.gov (United States)

    Beale, N. C. L.

    1985-08-01

    The paper begins with a reminder of the particular need for standards in LANs. We then describe the requirements of High Integrity LANs. Current developments in LAN standards are then outlined. It is argued that the requirements of industrial LANs lead ideally to reconfiguring fibre optic rings, for which there are two major emerging standards. These two (IEEE 802.5 and ANSI FDDI) and the Cambridge Ring are discussed and compared. One implementation - the HILAN is discussed.

  13. Ku80 Counters Oxidative Stress-Induced DNA Damage and Cataract Formation in the Human Lens.

    Science.gov (United States)

    Smith, Andrew John Oliver; Ball, Simon Sidney Robert; Manzar, Kamal; Bowater, Richard Peter; Wormstone, Ian Michael

    2015-12-01

    Oxidative stress in the human lens leads to a wide range of damage including DNA strand breaks, which are likely to contribute to cataract formation. The protein Ku80 is a fundamental component of the nonhomologous end-joining pathway that repairs DNA double strand breaks. This study investigates the putative impact of Ku80 in cataract prevention in the human lens. The present study used the human lens epithelial cell line FHL124 and whole human lens organ culture. Targeted siRNA was used to deplete Ku80, with Western blot and immunocytochemistry employed to assess Ku80 expression levels. Oxidative stress was induced with hydrogen peroxide and DNA strand breaks measured by alkaline comet assay and γH2AX foci counts. Visual quality of whole human lenses was measured with image analysis software. Expression of Ku80 was predominately found in the cell nucleus of both FHL124 cells and native human lens epithelium. Treatment of FHL124 cells and whole lens cultures with siRNA targeted against Ku80 resulted in a significant knockdown at the protein level. Application of oxidative stress (30 μM H2O2) created more DNA strand breaks when added to Ku80 knockdown cells than in scrambled siRNA control cells as determined by the alkaline comet assay and the number of γH2AX foci. In whole lens cultures, exposure to 1 mM H2O2 resulted in more lens opacity in Ku80 knockdown lenses than match-paired controls. Depletion of Ku80 in the lens through acute change or a consequence of aging is likely to increase levels of DNA strand breaks, which could negatively influence physiological function and promote lens opacity. It is therefore feasible that Ku80 plays a role in retarding cataract formation.

  14. Improved starch recovery from potatoes by enzymes and reduced water holding of the residual fibres.

    Science.gov (United States)

    Ramasamy, Urmila R; Lips, Steef; Bakker, Rob; Gruppen, Harry; Kabel, Mirjam A

    2014-11-26

    During the industrial extraction of starch from potatoes (Seresta), some starch remains within undisrupted potato cells in the fibrous side-stream. The aim of this study was to investigate if enzymatic degradation of cell wall polysaccharides (CWPs) can enhance starch recovery and lower the water holding capacity (WHC) of the "fibre" fraction. The use of a pectinase-rich preparation recovered 58% of the starch present in the "fibre" fraction. Also, the "fibre" fraction retained only 40% of the water present in the non-enzyme treated "fibre". This was caused by the degradation of pectins, in particular arabinogalactan side chains calculated as the sum of galactosyl and arabinosyl residues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Factors That Improve the Impact Responses of Ukam Plant Fibre ...

    African Journals Online (AJOL)

    Natural fibres around us have mechanical properties capable of making them compete effectively with synthetic fibres in the development of fibre reinforced composites. Synthetic fibres (such as glass fibres) and resins (such as polyester resin) have long been used in the development of structural components for car bodies, ...

  16. Plasmonic Luneburg lens antenna synthesized by metasurfaces with hexagonal lattices.

    Science.gov (United States)

    Chen, Kuang Cheng; Yang, Jiun Wen; Yang, Yueh-Chieh; Khin, Chang Fu; Kehn, M Ng Mou

    2017-10-30

    The metasurface lens composing of 2D periodic metallic patches on a grounded dielectric slab possesses several advantages such as being light, low-profile, compact, and also cheap to manufacture. In this paper, a Luneburg lens synthesized by a metasurface and designated for use as a surface wave antenna is proposed. Two types of unit cell will be compared, one whose surface wave modal dispersion varies significantly with the grazing direction and another that does not. In the context of being applied as surface wave antennas, it will be shown that the Luneburg lens synthesized by the latter kind of unit cell provides improved performance as compared to the former. Several aperture sub-efficiencies of the metasurface-based Luneburg-lens antenna shall be used for the characterization of the radiation. A prototype of the designed lens antenna has also been manufactured. Measurement results agree well with theoretical predictions and the efficacy of this device over a fairly wide bandwidth has been experimentally demonstrated.

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

    Science.gov (United States)

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

    2010-11-15

    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. 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. 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

  18. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...... of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish...

  19. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish......Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...

  20. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1998-01-01

    Durability studies are carried out at BKM as part of the research project "Design Methods for Fibre Reinforced Concrete" (FRC) involving BKM, The Concrete Research Center at DTI, Building Technology at Aalborg University, Rambøll, 4K-Beton and Rasmussen & Schiøtz. Concrete beams with or without...... fibre reinforcement are exposed to a combination of mechanical and environmental load to indicate whether fibre reinforcement will improve the durability of cracked concrete structures. Secondly, it is the aim to identify important mechanisms for the effect of the fibre reinforcement on the durability......) and polypropylene fibres (PP) are used in the concrete beams as well as main reinforcement. Results of the durability tests on cracked FRC-beams are compared with results for uncracked FRC-beams and beams without fibres....

  1. Theorem of comparative sensitivity of fibre sensors

    Science.gov (United States)

    Belovolov, M. I.; Paramonov, V. M.; Belovolov, M. M.

    2017-12-01

    We report an analysis of sensitivity of fibre sensors of physical quantities based on different types of interferometers. We formulate and prove the following theorem: under the time-dependent external physical perturbations at nonzero frequencies (i.e., except the static and low-frequency ones) on the sensitive arms of an interferometer in the form of multiturn elements (coils), there exist such lengths L of the measuring arms of the fibre interferometers at which the sensitivity of sensors based on the Sagnac fibre interferometers can be comparable with the sensitivity of sensors based on Michelson, Mach - Zehnder, or Fabry - Perot fibre interferometers, as well as exceed it under similar other conditions (similar-type perturbations, similar arm lengths and single-mode fibre types). The consequences that follow from the theorem, important for practical implementation of arrays of fibre sensors for measurement purposes and the devices with stable metrological properties, are discussed.

  2. Aquaporin 0 plays a pivotal role in refractive index gradient development in mammalian eye lens to prevent spherical aberration

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, S. Sindhu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, New York, NY (United States)

    2014-10-03

    Highlights: • Intact AQP0 functions as fiber cell-to-fiber cell adhesion protein. • AQP0 facilitates reduction in extracellular space and lens water content. • AQP0 adhesion function aids in lens refractive index gradient (RING) formation. • AQP0 prevents lens spherical aberration by establishing RING. • AQP0 is critical for lens transparency and homeostasis. - Abstract: Aquaporin 0 (AQP0) is a transmembrane channel that constitutes ∼45% of the total membrane protein of the fiber cells in mammalian lens. It is critical for lens transparency and homeostasis as mutations and knockout cause autosomal dominant lens cataract. AQP0 functions as a water channel and as a cell-to-cell adhesion (CTCA) molecule in the lens. Our recent in vitro studies showed that the CTCA function of AQP0 could be crucial to establish lens refractive index gradient (RING). However, there is a lack of in vivo data to corroborate the role of AQP0 as a fiber CTCA molecule which is critical for creating lens RING. The present investigation is undertaken to gather in vivo evidence for the involvement of AQP0 in developing lens RING. Lenses of wild type (WT) mouse, AQP0 knockout (heterozygous, AQP0{sup +/−}) and AQP0 knockout lens transgenically expressing AQP1 (heterozygous AQP0{sup +/−}/AQP1{sup +/−}) mouse models were used for the study. Data on AQP0 protein profile of intact and N- and/or C-terminal cleaved AQP0 in the lens by MALDI-TOF mass spectrometry and SDS–PAGE revealed that outer cortex fiber cells have only intact AQP0 of ∼28 kDa, inner cortical and outer nuclear fiber cells have both intact and cleaved forms, and inner nuclear fiber cells have only cleaved forms (∼26–24 kDa). Knocking out of 50% of AQP0 protein caused light scattering, spherical aberration (SA) and cataract. Restoring the lost fiber cell membrane water permeability (P{sub f}) by transgene AQP1 did not reinstate complete lens transparency and the mouse lenses showed light scattering and SA

  3. Influence of fibre orientation on the performance of steel fibre-reinforced concrete

    OpenAIRE

    Grünewald, Steffen; Laranjeira de Oliveira, Filipe; Walraven, Joost; Aguado de Cea, Antonio; Molins i Borrell, Climent

    2012-01-01

    The performance of fibre-reinforced materials in the hardened state depends on the material behaviour, the production method and influences related to the structure. The position and the orientation of fibres in a structure can differ from the homogenous distribution and the random orientation in a mixer. Due to the flow of the concrete, fibres are able to orient which makes the prediction of the structural behaviour of fibre-reinforced concrete more complex, but it also offers the potential ...

  4. A second look into fibre typing--relation to meat quality.

    Science.gov (United States)

    Lefaucheur, L

    2010-02-01

    Despite intensive research, a large variation in meat quality is still observed in most meat producing species. It is widely accepted that myofibre type composition is an important source of variation in meat quality. However, the identification of specific and universal relationships between myofibre characteristics, growth performance and meat quality traits remains a challenge. After the presentation of recent knowledge underlying fibre typing, this review describes the involvements of Ca2+-dependent mechanisms, and the energy state of the myofibres in the control of contractile and metabolic properties, with a special attention to the AMP-activated protein kinase pathway and mitochondrial compartment. In order to identify muscle components which could mask specific relationships between fibre type composition and meat quality, an analysis of the interactions between myofibres and other muscle cellular components is presented. After a brief description of myogenesis, the significance of the total number of fibres, myofibre cross-sectional area and fibre type composition for growth performance and meat quality is presented. Then, some genetic and environmental factors are proposed as possible tools to control meat quality trough the modulation of fibre type characteristics. Finally, a conclusion makes the point on bottlenecks still preventing the identification of specific relationships between fibre characteristics, growth performance and meat quality, and suggests future perspectives such as direct selection on fibre traits and study of correlated responses, the development of in vitro approaches using cell cultures, manipulation of myogenesis during the fetal period, and the production and use of genetically modified animals.

  5. Glucose intolerance in the West African Diaspora: a skeletal muscle fibre type distribution hypothesis.

    Science.gov (United States)

    Nielsen, J; Christensen, D L

    2011-08-01

    In the United States, Black Americans are largely descendants of West African slaves; they have a higher relative proportion of obesity and experience a higher prevalence of diabetes than White Americans. However, obesity rates alone cannot explain the higher prevalence of type 2 diabetes. Type 2 diabetes is characterized by insulin resistance and beta-cell dysfunction. We hypothesize that the higher prevalence of type 2 diabetes in African Americans (as compared to White Americans) is facilitated by an inherited higher percentage of skeletal muscle fibre type II and a lower percentage of skeletal muscle fibre type I. Skeletal muscle fibre type II is less oxidative and more glycolytic than skeletal muscle fibre type I. Lower oxidative capacity is associated with lower fat oxidation and a higher disposal of lipids, which are stored as muscular adipose tissue in higher amounts in Black compared to White Americans. In physically active individuals, the influence of muscle fibre composition will not be as detrimental as in physically inactive individuals. This discrepancy is caused by the plasticity in the skeletal muscle fibre characteristics towards a higher activity of oxidative enzymes as a consequence of physical activity. We suggest that a higher percentage of skeletal muscle fibre type II combined with physical inactivity has an impact on insulin sensitivity and high prevalence of type 2 diabetes in Blacks of West African ancestry. © 2011 The Authors. Acta Physiologica © 2011 Scandinavian Physiological Society.

  6. Crystal structure of the fibre head domain of the Atadenovirus Snake Adenovirus 1.

    Directory of Open Access Journals (Sweden)

    Abhimanyu K Singh

    Full Text Available Adenoviruses are non-enveloped icosahedral viruses with trimeric fibre proteins protruding from their vertices. There are five known genera, from which only Mastadenoviruses have been widely studied. Apart from studying adenovirus as a biological model system and with a view to prevent or combat viral infection, there is a major interest in using adenovirus for vaccination, cancer therapy and gene therapy purposes. Adenoviruses from the Atadenovirus genus have been isolated from squamate reptile hosts, ruminants and birds and have a characteristic gene organization and capsid morphology. The carboxy-terminal virus-distal fibre head domains are likely responsible for primary receptor recognition. We determined the high-resolution crystal structure of the Snake Adenovirus 1 (SnAdV-1 fibre head using the multi-wavelength anomalous dispersion (MAD method. Despite the absence of significant sequence homology, this Atadenovirus fibre head has the same beta-sandwich propeller topology as other adenovirus fibre heads. However, it is about half the size, mainly due to much shorter loops connecting the beta-strands. The detailed structure of the SnAdV-1 fibre head and other animal adenovirus fibre heads, together with the future identification of their natural receptors, may lead to the development of new strategies to target adenovirus vectors to cells of interest.

  7. Study of the tensile properties of individual multicellular fibres generated by Bacillus subtilis

    Science.gov (United States)

    Ye, Xuan; Zhao, Liang; Liang, Jiecun; Li, Xide; Chen, Guo-Qiang

    2017-04-01

    Multicellular fibres formed by Bacillus subtilis (B. subtilis) are attracting interest because of their potential application as degradable biomaterials. However, mechanical properties of individual fibres remain unknown because of their small dimensions. Herein, a new approach is developed to investigate the tensile properties of individual fibres with an average diameter of 0.7 μm and a length range of 25.7-254.3 μm. Variations in the tensile strengths of fibres are found to be the result of variable interactions among pairs of microbial cells known as septa. Using Weibull weakest-link model to study this mechanical variability, we predict the length effect of the sample. Moreover, the mechanical properties of fibres are found to depend highly on relative humidity (RH), with a brittle-ductile transition occurring around RH = 45%. The elastic modulus is 5.8 GPa in the brittle state, while decreases to 62.2 MPa in the ductile state. The properties of fibres are investigated by using a spring model (RH  45%) for the time-dependent response. Loading-unloading experiments and numerical calculations demonstrate that necking instability comes from structural changes (septa) and viscoelasticity dominates the deformation of fibres at high RH.

  8. Calculation of the dynamic air flow resistivity of fibre materials

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1997-01-01

    The acoustic attenuation of acoustic fiber materials is mainly determined by the dynamic resistivity to an oscillating air flow. The dynamic resistance is calculated for a model with geometry close to the geometry of real fibre material. The model constists of parallel cylinders placed randomly.......The second procedure is an extension to oscillating air flow of the Brinkman self-consistent procedure for dc flow. The procedures are valid for volume concentrations of cylinders less than 0.1. The calculations show that for the density of fibers of interest for acoustic fibre materials the simple self....... Two case are treated: flow perpendicular to the cylinder axes, and flow parallel to the axes. In each case two new approximate procedures were used. In the first procedure, one solves the equation of flow in a Voronoi cell around the fiber, and averages over the distribution of the Voronoi cells...

  9. Strength variability of single flax fibres

    DEFF Research Database (Denmark)

    Aslan, Mustafa; Chinga-Carrasco, G.; Sørensen, Bent F.

    2011-01-01

    (linear and nonlinear) of the fibres are found to be correlated with the amount of defects. The linear stress–strain curves tend to show a higher tensile strength, a higher Young’s modulus, and a lower strain to failure than the nonlinear curves. Finally, the fibres are found to fracture by a complex......Due to the typical large variability in the measured mechanical properties of flax fibres, they are often employed only in low grade composite applications. The present study aims to investigate the reasons for the variability in tensile properties of flax fibres. It is found that an inaccuracy...

  10. Microstructural characterization of stone wool fibre network

    DEFF Research Database (Denmark)

    Chapelle, Lucie; Brøndsted, Povl; Kusano, Yukihiro

    2014-01-01

    as the number density of fibre contacts. The methods are based on image analysis of 3D datasets which have been obtained by x-ray tomography. Validation of the proposed methods was demonstrated by testing generated virtual fibrous network with known fibre characteristics.......Understanding the mechanical properties of fibrous network as complex as stone wool materials requires a relevant description of their microstructure and architecture. In this study, different methods have been proposed to characterize the fibre orientation, diameter and length of fibres as well...

  11. A novel photonic crystal fibre switch

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Hermann, D.S.; Broeng, Jes

    2003-01-01

    A new thermo-optic fibre switch is demonstrated, which utilizes the phase transitions of a thermochromic liquid crystal inside a photonic crystal fibre. We report an extinction ratio of 60 dB and an insertion loss of 1 dB.......A new thermo-optic fibre switch is demonstrated, which utilizes the phase transitions of a thermochromic liquid crystal inside a photonic crystal fibre. We report an extinction ratio of 60 dB and an insertion loss of 1 dB....

  12. A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

    International Nuclear Information System (INIS)

    Hopmann, Ch.; Weber, M.; Haag, J. van; Schöngart, M.

    2015-01-01

    To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material’s properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA

  13. [Contact lens care and maintenance].

    Science.gov (United States)

    Bloise, L

    2017-04-01

    All contact lenses with replacement schedules longer than daily must be maintained. At each step of their use, the lenses may be contaminated. Contact lens solutions perform the essential functions of cleaning, decontaminating and preserving the lenses to prevent infectious problems and improve wearing comfort. Contact lens contamination essentially comes from hands, cleaning solutions, cases, water and the environment. The pathogenic microorganisms are mainly Gram-negative bacteria, fungi and amoebae. Contact lens deposits may or may not have an organic origin. Their presence increases the risk of infection because they serve as a nutrient matrix for microbes, and they are responsible for wearing discomfort. Contact lens solutions differ in their composition, their mechanism of action and the concentration of the various agents. To prescribe the best lens care system to each wearer and for each material, it is necessary to be very familiar with them. Maintenance is the main cause of discomfort with contact lenses, either through improper use, solution-material incompatibility, or a reaction of the wearer to the components. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Applying elastic fibre biology in vascular tissue engineering

    OpenAIRE

    Kielty, Cay M; Stephan, Simon; Sherratt, Michael J; Williamson, Matthew; Shuttleworth, C. Adrian

    2007-01-01

    For the treatment of vascular disease, the major cause of death in Western society, there is an urgent need for tissue-engineered, biocompatible, small calibre artery substitutes that restore biological function. Vascular tissue engineering of such grafts involves the development of compliant synthetic or biomaterial scaffolds that incorporate vascular cells and extracellular matrix. Elastic fibres are major structural elements of arterial walls that can enhance vascular graft design and pate...

  15. Blast Resistance of Slurry Infiltrated Fibre Concrete with Waste Steel Fibres from Tires

    Directory of Open Access Journals (Sweden)

    Drdlová Martina

    2018-01-01

    Full Text Available The utilization of waste steel fibres (coming from the recycling process of the old tires in production of blast resistant cement based panels was assessed. Waste fibres were incorporated in slurry infiltrated fibre concrete (SIFCON, which is a special type of ultra-highperformance fibre reinforced concrete with high fibre content. The technological feasibility (i.e. suitability of the waste fibres for SIFCON technology was assessed using homogeneity test. Test specimens were prepared with three volume fractions (5; 7.5 and 10 % by vol. of waste unclassified fibres. SIFCON with industrial steel fibres (10% by vol. and ultra-highperformance fibre concrete with industrial fibres were also cast and tested for comparison purposes. Quasi-static mechanical properties were determined. Real blast tests were performed on the slab specimens (500x500x40 mm according to the modified methodology M-T0-VTU0 10/09. Damage of the slab, the change of the ultrasound wave velocity propagation in the slab specimen before and after the blast load in certain measurement points, the weight of fragments and their damage potential were evaluated and compared. Realized tests confirmed the possibility of using the waste fibres for SIFCON technology. The obtained results indicate, that the usage of waste fibres does not significantly reduce the values of SIFCON flexural and compressive strength at quasi-static load - the values were comparable to the specimens with industrially produced fibres. With increasing fibre content, the mechanical parameters are increasing as well. Using of the waste fibres reduces fragmentation of SIFCON at blast load due to the fibre size parameters. Using of low diameter fibres means more fibres in the matrix and thus better homogeneity of the whole composite with less unreinforced areas. Regarding the blast tests, the specimen with waste steel fibres showed the best resistance and outperformed also the specimen with commercial fibres. Using of

  16. Optical fibre probes in the measurement of scattered light ...

    Indian Academy of Sciences (India)

    2014-01-08

    based mea- surements and sensors. An optrode usually comprises a bundle of multimode fibres, out of which one or more fibres are used for irradiating the sample, and the remaining fibres are used to collect the.

  17. Surface treated polypropylene (PP) fibres for reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    López-Buendía, Angel M., E-mail: buendia@uv.es [AIDICO Technological Institute of Construction, Benjamin Franklin 17, 46380 Paterna, Valencia (Spain); Romero-Sánchez, María Dolores [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain); Climent, Verónica [Lafarge Cementos, Polígono Sepes, Isaac Newton s/n, 46500 Sagunto, Valencia (Spain); Guillem, Celia [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain)

    2013-12-15

    Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment.

  18. Strength training increases the size of the satellite cell pool in type I and II fibres of chronically painful trapezius muscle in females

    DEFF Research Database (Denmark)

    Mackey, Abigail; Andersen, Lars L; Frandsen, Ulrik

    2011-01-01

    While strength training has been shown to be effective in mediating hypertrophy and reducing pain in trapezius myalgia, responses at the cellular level have not previously been studied. This study investigated the potential of strength training targeting the affected muscles (SST, n = 18......) and general fitness training (GFT, n = 16) to augment the satellite cell (SC) and macrophage pools in the trapezius muscles of women diagnosed with trapezius myalgia. A group receiving general health information (REF, n = 8) served as a control. Muscle biopsies were collected from the trapezius muscles...... hypertrophy (r = -0.669, P = 0.005). SST also resulted in a 74% enhancement of the trapezius macrophage content (P

  19. Mechanical, degradation and cytocompatibility properties of magnesium coated phosphate glass fibre reinforced polycaprolactone composites.

    Science.gov (United States)

    Liu, Xiaoling; Hasan, Muhammad S; Grant, David M; Harper, Lee T; Parsons, Andrew J; Palmer, Graham; Rudd, Chris D; Ahmed, Ifty

    2014-11-01

    Retention of mechanical properties of phosphate glass fibre reinforced degradable polyesters such as polycaprolactone and polylactic acid in aqueous media has been shown to be strongly influenced by the integrity of the fibre/polymer interface. A previous study utilising 'single fibre' fragmentation tests found that coating with magnesium improved the fibre and matrix interfacial shear strength. Therefore, the aim of this study was to investigate the effects of a magnesium coating on the manufacture and characterisation of a random chopped fibre reinforced polycaprolactone composite. Short chopped strand non-woven phosphate glass fibre mats were sputter coated with degradable magnesium to manufacture phosphate glass fibre/polycaprolactone composites. The degradation behaviour (water uptake, mass loss and pH change of the media) of these polycaprolactone composites as well as of pure polycaprolactone was investigated in phosphate buffered saline. The Mg coated fibre reinforced composites revealed less water uptake and mass loss during degradation compared to the non-coated composites. The cations released were also explored and a lower ion release profile for all three cations investigated (namely Na(+), Mg(2+) and Ca(2+)) was seen for the Mg coated composite samples. An increase of 17% in tensile strength and 47% in tensile modulus was obtained for the Mg coated composite samples. Both flexural and tensile properties were investigated and a higher retention of mechanical properties was obtained for the Mg coated fibre reinforced composite samples up to 10 days immersion in PBS. Cytocompatibility study showed both composite samples (coated and non-coated) had good cytocompatibility with human osteosarcoma cell line. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  20. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  1. Compliance among soft contact lens wearers.

    Science.gov (United States)

    Kuzman, Tomislav; Kutija, Marija Barisić; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurisić, Darija; Skegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-12-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in different aspects of lens care handling and wearing habits. In our research 50 asymptomatic lens wearers filled out a questionnaire containing demographic data, lens type, hygiene and wearing habits, lenses and lens care system replacement schedule and self-evaluation of contact lens handling hygiene. We established criteria of compliance according to available manufacturer's recommendations, prior literature and our clinical experience. Only 2 (4%) of patients were fully compliant SCL wearers. The most common non-compliant behaviours were insufficient lens solution soaking time (62%), followed by failure to daily exchange lens case solution and showering while wearing lenses. 44% of patients reported storing lenses in saline solution. Mean lens storage case replacement was 3.6 months, with up to 78% patients replacing lens case at least once in 3 months. Average grade in self evaluating level of compliance was very good (4 +/- 0.78) (from 1-poor level of hygiene to 5-great level of hygiene). Lens wearers who reported excessive daily lens wear and more than 10 years of lens wearing experience were also found to be less compliant with other lens system care procedures. (t = -2.99, df=47, p lens system maintenance steps. Most common non-compliant behaviours were the ones that are crucial for maintaining lens sterility and preventing infection. Despite the low objective compliance rate, self grading was relatively high. Therefore, these results indicate the need for patient

  2. Salvaging an Abused Lens or How a 4½ inch Brashear lens came unglued before I did!

    Science.gov (United States)

    Koester, Jack

    The author's newly-acquired Brashear telescope has a "fogged lens" that was stuck in its cell. After getting advice from several ATS members, the author visits Richard A. Buchroeder, the professional optical designer, who heats the mirror and cell in order to soften the binding substance by floating the cell in a pot filled with heated cooking oil. The process worked, and the two lenses were removed.

  3. Postponed sowing does not alter the fibre/wood ratio or fibre extractability of fibre hemp (Cannabis sativa)

    NARCIS (Netherlands)

    Westerhuis, W.; Struik, P.C.; Dam, van J.E.G.; Stomph, T.J.

    2009-01-01

    Because hemp is a short-day plant, postponing the sowing date might be a suitable strategy to obtain shorter and smaller plants around flowering, when primary fibres are 'ripe' enough to be harvested. Smaller plants can be processed on existing flax scutching and hackling lines and might have fibre

  4. Endogenous hydrogen peroxide production in the epithelium of the developing embryonic lens.

    Science.gov (United States)

    Basu, Subhasree; Rajakaruna, Suren; Dickinson, Bryan C; Chang, Christopher J; Menko, A Sue

    2014-01-01

    Hydrogen peroxide (H2O2) is an endogenously produced reactive oxygen species (ROS) present in a variety of mammalian systems. This particular ROS can play dichotomous roles, being beneficial in some cases and deleterious in others, which reflects the level and location of H2O2 production. While much is known about the redox regulation of ROS by antioxidant and repair systems in the lens, little is known about the endogenous production of H2O2 in embryonic lens tissue or the physiologic relevance of endogenous H2O2 to lens development. This gap in knowledge exists primarily from a lack of reagents that can specifically detect endogenous H2O2 in the intact lens. Here, using a recently developed chemoselective fluorescent boronate probe, peroxyfluor-6 acetoxymethyl ester (PF6-AM), which selectively detects H2O2 over related ROS, we examined the endogenous H2O2 signals in the embryonic lens. Embryonic day 10 chick whole lenses in ex vivo organ culture and lens epithelial cells in primary culture were loaded with the H2O2 probe PF6-AM. To determine the relationship between localization of mitochondria with active membrane potential and the region of H2O2 production in the lens, cells were exposed to the mitochondrial probe MitoTracker Red CMXRos together with PF6-AM. Diphenyleneiodonium (DPI), a flavin inhibitor that blocks generation of intracellular ROS production, was used to confirm that the signal from PF6-AM was due to endogenous ROS production. All imaging was performed by live confocal microscopy. PF6-AM detected endogenous H2O2 in lens epithelial cells in whole lenses in ex vivo culture and in lens epithelial cells grown in primary culture. No endogenous H2O2 signal could be detected in differentiating lens fiber cells with this probe. Treatment with DPI markedly attenuated the fluorescence signal from the peroxide-specific probe PF6-AM in the lens epithelium, suggesting that basal generation of ROS occurs in this region. The lens epithelial cells producing an

  5. EXPERIMENTAL STUDY ON LIGHT TRANSMITTING CONCRETE BY USING OPTICAL FIBRE

    OpenAIRE

    S. Suganya; S. Minu Gopika

    2017-01-01

    Light transmitting concrete is one of the fibre reinforced concrete which is mainly used for aesthetic application by incorporating the optical fibres in concrete. Optical fibres help to transmit the light through the fibres and the end-light type of fibre is used to increase the aesthetic appearance of the concrete which is like a transparent concrete. Fibres are arranged in different layers, to increase the load carrying capacity and also the pattern can be created to make the concrete deco...

  6. Properties of self-compacting fibre reinforced concrete

    OpenAIRE

    Vandewalle, Lucie; Heirman, Gert

    2009-01-01

    The postcracking behaviour of fibre reinforced concrete is particularly influenced by the fibre distribution and the fibre orientation. One could suppose that in self-compacting fibre reinforced concrete (SCFRC) fibres orient along the flow due to the wall-effect, the flow direction and the velocity profile in the concrete. To investigate the fresh and hardened characteristics (mechanical properties, orientation and distribution of the fibres) of SCFRC and to relate them to those of tradition...

  7. Corneal nerve fibre damage precedes diabetic retinopathy in patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Bitirgen, G; Ozkagnici, A; Malik, R A; Kerimoglu, H

    2014-04-01

    To quantify the morphological alterations in corneal nerve fibres and cells in patients with type 2 diabetes mellitus in relation to the severity of diabetic retinopathy. One hundred and thirty-two eyes of 132 patients with type 2 diabetes and 32 eyes of 32 healthy control subjects were evaluated with in vivo corneal confocal microscopy. Patients with diabetes were classified into three groups: patients without diabetic retinopathy, patients with non-proliferative diabetic retinopathy and patients with proliferative diabetic retinopathy. Anterior and posterior stromal keratocyte, endothelial cell and basal epithelial cell densities and sub-basal nerve fibre structure were evaluated. Significant reductions in basal epithelial cell, anterior stromal keratocyte and endothelial cell densities were observed only in patients with diabetic retinopathy. However, nerve fibre density, nerve branch density and nerve fibre length were reduced in patients without diabetic retinopathy and worsened progressively with increasing severity of retinopathy. Corneal cell pathology occurs in patients with diabetic retinopathy, but corneal nerve fibre damage seems to precede the development of diabetic retinopathy. © 2013 The Authors. Diabetic Medicine © 2013 Diabetes UK.

  8. Soluble Fibre Meal Challenge Reduces Airway Inflammation and Expression of GPR43 and GPR41 in Asthma

    Directory of Open Access Journals (Sweden)

    Isabel Halnes

    2017-01-01

    Full Text Available Short chain fatty acids (SCFAs are produced following the fermentation of soluble fibre by gut bacteria. In animal models, both dietary fibre and SCFAs have demonstrated anti-inflammatory effects via the activation of free fatty acid receptors, such as G protein-coupled receptor 41 and 43 (GPR41 and GPR43. This pilot study examined the acute effect of a single dose of soluble fibre on airway inflammation—including changes in gene expression of free fatty acid receptors—in asthma. Adults with stable asthma consumed a soluble fibre meal (n = 17 containing 3.5 g inulin and probiotics, or a control meal (n = 12 of simple carbohydrates. Exhaled nitric oxide (eNO was measured and induced sputum was collected at 0 and 4 h for differential cell counts, measurement of interleukin-8 (IL-8 protein concentration, and GPR41 and GPR43 gene expression. At 4 h after meal consumption, airway inflammation biomarkers, including sputum total cell count, neutrophils, macrophages, lymphocytes, sputum IL-8, and eNO significantly decreased compared to baseline in the soluble fibre group only. This corresponded with upregulated GPR41 and GPR43 sputum gene expression and improved lung function in the soluble fibre group alone. Soluble fibre has acute anti-inflammatory effects in asthmatic airways. Long-term effects of soluble fibre as an anti-inflammatory therapy in asthma warrants further investigation.

  9. Soluble Fibre Meal Challenge Reduces Airway Inflammation and Expression of GPR43 and GPR41 in Asthma

    Science.gov (United States)

    Halnes, Isabel; Baines, Katherine J.; Berthon, Bronwyn S.; MacDonald-Wicks, Lesley K.; Gibson, Peter G.; Wood, Lisa G.

    2017-01-01

    Short chain fatty acids (SCFAs) are produced following the fermentation of soluble fibre by gut bacteria. In animal models, both dietary fibre and SCFAs have demonstrated anti-inflammatory effects via the activation of free fatty acid receptors, such as G protein-coupled receptor 41 and 43 (GPR41 and GPR43). This pilot study examined the acute effect of a single dose of soluble fibre on airway inflammation—including changes in gene expression of free fatty acid receptors—in asthma. Adults with stable asthma consumed a soluble fibre meal (n = 17) containing 3.5 g inulin and probiotics, or a control meal (n = 12) of simple carbohydrates. Exhaled nitric oxide (eNO) was measured and induced sputum was collected at 0 and 4 h for differential cell counts, measurement of interleukin-8 (IL-8) protein concentration, and GPR41 and GPR43 gene expression. At 4 h after meal consumption, airway inflammation biomarkers, including sputum total cell count, neutrophils, macrophages, lymphocytes, sputum IL-8, and eNO significantly decreased compared to baseline in the soluble fibre group only. This corresponded with upregulated GPR41 and GPR43 sputum gene expression and improved lung function in the soluble fibre group alone. Soluble fibre has acute anti-inflammatory effects in asthmatic airways. Long-term effects of soluble fibre as an anti-inflammatory therapy in asthma warrants further investigation. PMID:28075383

  10. Broadband focusing of underwater sound using a transparent pentamode lens.

    Science.gov (United States)

    Su, Xiaoshi; Norris, Andrew N; Cushing, Colby W; Haberman, Michael R; Wilson, Preston S

    2017-06-01

    An inhomogeneous acoustic metamaterial lens based on spatial variation of refractive index for broadband focusing of underwater sound is reported. The index gradient follows a modified hyperbolic secant profile designed to reduce aberration and suppress side lobes. The gradient index (GRIN) lens is comprised of transversely isotropic hexagonal microstructures with tunable quasi-static bulk modulus and mass density. In addition, the unit cells are impedance-matched to water and have in-plane shear modulus negligible compared to the effective bulk modulus. The flat GRIN lens is fabricated by cutting hexagonal centimeter scale hollow microstructures in aluminum plates, which are then stacked and sealed from the exterior water. Broadband focusing effects are observed within the homogenization regime of the lattice in both finite element simulations and underwater measurements (20-40 kHz). This design approach has potential applications in medical ultrasound imaging and underwater acoustic communications.

  11. Concretes reinforced with acrylic fibres

    Directory of Open Access Journals (Sweden)

    Amat, T.

    1997-12-01

    Full Text Available This article is based on works, carried out at the IETcc, aimed to evaluate the behaviour of concretes reinforced with acrylic polyacrylonitrile fibres, and to study the influence they have on concrete physical and mechanical properties.

    El presente artículo está basado en trabajos realizados en el Instituto de Ciencias de la Construcción Eduardo Torroja, teniendo por objetivo evaluar el comportamiento de los hormigones reforzados con fibras acrílicas de poliacrilonitrilo, estudiando la influencia que tiene sobre sus propiedades físicas y mecánicas.

  12. A PHOTONIC BAND GAP FIBRE

    DEFF Research Database (Denmark)

    1999-01-01

    An optical fibre having a periodicidal cladding structure provididing a photonic band gap structure with superior qualities. The periodical structure being one wherein high index areas are defined and wherein these are separated using a number of methods. One such method is the introduction...... of additional low index elements, another method is providing elongated elements deformed in relation to a circular cross section. Also described is a cladding structure comprising elongated elements of a material having an index of refraction higher than that of the material adjacent thereto. Using...

  13. Scintillating fibre tracking neutron detector

    International Nuclear Information System (INIS)

    Karlsson, Joakim.

    1995-04-01

    A detector for measurements of collimated fluxes of neutrons in the energy range 2-20 MeV is proposed. It utilizes (n.p) elastic scattering in scintillating optical fibres placed in successive orthogonal layers perpendicular to the neutron flux. A test module has been designed, constructed and tested with respect to separation of neutron and gamma events. The pulse height measurements show the feasibility to discriminate between neutron, gamma and background events. Application to measurements of fusion neutrons is considered. 18 refs, 22 figs, 4 tabs

  14. Human Dietary Fibre: A Review,

    Science.gov (United States)

    1979-05-01

    largely overcome by initial lipid extract iomi . 2 ) Starch can remain insoluble in the hot detergent and 1~e measure d withresidual NI )F. E nzvm u a t i...unavailable to animals. This was referred to as “crude fibre”. Crude fibre analysis consists of extract ion wit h petroleum ether , follow- ed by acid, then...with a cuticular laver on the outer surface. Potato is ~ii exani p le. (ii) Leaf Structure : These are lightl y l ignif ied , have a cut icular layer and

  15. Computer-aided lens assembly

    Science.gov (United States)

    Tomlinson, Richard; Alcock, Rob; Petzing, Jon; Coupland, Jeremy

    2004-01-01

    We propose a computer-aided method of lens manufacture that allows assembly, adjustment, and test phases to be run concurrently until an acceptable level of optical performance is reached. Misalignment of elements within a compound lens is determined by a comparison of the results of physical ray tracing by use of an array of Gaussian laser beams with numerically obtained geometric ray traces. An estimate of misalignment errors is made, and individual elements are adjusted in an iterative manner until performance criteria are achieved. The method is illustrated for the alignment of an air-spaced doublet.

  16. Acanthamoeba keratitis. Contact lens and noncontact lens characteristics.

    Science.gov (United States)

    Chynn, E W; Lopez, M A; Pavan-Langston, D; Talamo, J H

    1995-09-01

    To identify potential differences in time to diagnosis and final visual outcome between contact lens and noncontact lens users with Acanthamoeba keratitis. Prior studies have shown early diagnosis and therapy to be related to outcome but have not analyzed differences among patients with and without contact lenses. A retrospective analysis of 11 consecutive cases (involving 13 eyes) of Acanthamoeba keratitis diagnosed at one institution over a 3-year period. Mean time to diagnosis was significantly longer in noncontact lens users versus those who wore contact lenses (mean, 5.8 versus 3.3 weeks). Fifty percent of patients who did not wear contact lenses had a poor outcome (visual acuity worse than 20/40 or penetrating keratoplasty) versus 14% of patients who wore contact lenses. Diagnoses were made later in patients without contact lenses, and these patients had a worse visual outcome than those with Acanthamoeba keratitis who wore contact lenses. All patients with unresponsive microbial keratitis, even those without contact lens use, should be evaluated for Acanthamoeba.

  17. Characterisation of Flax Fibres and Flax Fibre Composites. Being cellulose based sources of materials

    DEFF Research Database (Denmark)

    Aslan, Mustafa

    a transition value, as predicted by the volumetric composition model. This leads furthermore to a scatter in the experimental data of stiffness at high fibre weight fractions. The qualitative analysis of the composite cross sections by microscopy also shows that the low and high pressure composites have......Cellulosic fibres, like wood and plant fibres, have the potential for use as load-bearing constituents in composite materials due to their attractive properties such as high stiffness-to-weight ratio that makes cellulosic fibre composites ideal for many structural applications. There is thus...... a growing interest among composite manufacturers for such low-cost and low-weight cellulosic fibre composites. In addition, wood and plant fibre based composites with thermoplastic polymeric matrices are recyclable, and they are cost attractive alternatives to oil based fibre reinforced polymer composites...

  18. Oral Morphine Consumption Reduces Lens Development in Rat Embryos

    Directory of Open Access Journals (Sweden)

    Hossein Bahadoran

    2012-07-01

    Full Text Available Objective: Consumption of morphine, during pregnancy, in addition to inducing defects in the mother’s nervous system function, caused defects or delays in the formation and evolution of embryonic visual system. In the present study, changes in lens development was assessed in embryos exposed in utero to morphine. Material and Methods: Female Wistar rats (250-300 g were mated with male rats and pregnancy was determined by sperm observation in vaginal smear. This day was considered as embryonic day zero (E0. The females were then divided randomly into the experimental and the control groups. The control group received tap water and the experimental group received morphine (0.05 mg/ml in their water. On embryonic day 13 ( E13, blood samples were collected from the retro-orbital sinus of all animals for plasma corticosterone detection. On embryonic day 17(E17, the animals were killed by an overdose of chloroform and the embryos were taken out surgically. The embryos were fixed in 10% formalin for 30 days. At this time, the head of the embryos were removed for tissue processing and Hematoxylin- Eosin (H&E staining. The samples were evaluated using light microscope and MOTIC software. Results: Our data indicated that plasma corticosterone level was dramatically increased and the lens was thinner in the experimental group. (Although the proliferation of lens cells increased in the experiment group but that lens had delay in removing the proliferated and elongation cells with abnormal density in the lateral part of the lens in compare with control group. I have no idea what the authors are stating here. Moreover, the opening of the eyelids was delayed in the off springs of the mothers who received morphine. Conclusions: This study showed that morphine consumption during pregnancy leads to defects in fetal visual system development, particularly in the lens, and eyelids.

  19. ASSESSMENT OF FIBRE CHARACTERISTICS AND SUITABILITY ...

    African Journals Online (AJOL)

    Samuel

    Key Words: Maize, husk, stalk, pulp, and fibre length. INTRODUCTION. Paper is one of the most fundamental things that is widely used by many people across the globe. The world consumption of ... around the world are used by paper industries on every continent. ..... On the fin structure of bamboo fibres. Wood Science.

  20. Winding of fibre composites; Vikling af fiberkompositter

    Energy Technology Data Exchange (ETDEWEB)

    Lystrup, Aage

    2006-01-01

    Within the project 'Storage of hydrogen in advanced high pressure vessels' under the PSO-R AND D 2005 program one of the tasks is to describe the technology, which is used for manufacturing of fibre reinforced pressure vessels. Fibre reinforced pressure vessels for high pressures are manufactured by winding structural load bearing fibres around a mandrel or an internal liner. There are two different types of cylindrical pressure vessels: 1) Cylinders with thick metal liner, where only the cylindrical part is over wrapped with hoop windings, and 2) cylinders with a thin metal or polymer liner, where both the cylindrical part and the end domes are over wrapped with more layers with different fibre orientations (helical and hoop windings). This report describes the fundamental principles for filament winding of fibre reinforced polymer composites. After a short introduction to the advanced fibre composites, their properties and semi-raw materials used for fibre composites, the focus is on the process parameters, which have influence on the material quality of filament wound components. The report is both covering winding of fibre reinforced thermo-setting polymers as well as thermoplastic polymers, and there are references to vendors of filament winding machines, accessory equipment and computer software for design and manufacturing of filament wound components. (au)

  1. Insertion of optic fibre for CMS

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    The MicroJET system uses high pressure to carefully put the optical fibres into their protective tubes. These fibres are vital for rapid data transfer, but are also very delicate and, if damanged, may not work at the required efficiency. Similiar methods are used to install cables for the telecommunications industry.

  2. Fibre digestion in the hyra;r

    African Journals Online (AJOL)

    dried samples by calorimeter combustion. The fibre con- tent was determined by the method of Van Soest (1964) us- ing a Fibretec 1020 hot extraction apparatus. Two-way analysis of variance was used to test for differences between the two most important fibre digesting gut regions, the sac- culation and caeca. Results.

  3. low pump power photonic crystal fibre amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.; Broeng, Jes; Bjarklev, Anders Overgaard

    2003-01-01

    Designs of low pump power optical amplifiers, based on photonic crystal fibres are presented. The potential of these fibre amplifiers is investigated, and it is demonstrated that such amplifiers may deliver gains of more than 15 dB at 1550 nm with less than 1 mW of optical pump power....

  4. Recent advances in poled optical fibres

    DEFF Research Database (Denmark)

    Pruneri, V.; Margulis, W.; Myrén, N.

    2005-01-01

    A second-order nonlinearity can be induced in optical fibres through poling. We describe accomplishments of the EU project GLAMOROUS in making low-cost high performance electrooptic and nonlinear optical fibre- and waveguide-based components. In particular a comparison with more traditional...

  5. Durability of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard

    1996-01-01

    The planned research will indicate, whether fibre reinforced concrete has better or worse durability than normal concrete. Durability specimens will be measured on cracked as well as uncracked specimens. Also the pore structure in the concrete will be characterized.Keywords: Fibre reinforced...... concrete, durability, pore structure, mechanical load...

  6. Mohair, cashmere and other animal hair fibres

    CSIR Research Space (South Africa)

    Hunter, L

    2012-11-01

    Full Text Available Although luxury animal fibres, excluding silk, represent far less than 0.1% of global fibre production, they play a very significant role in the luxury, high value-added end of the market, notably the apparel market, being renowned for their special...

  7. Thermally induced structural changes in Nomex fibres

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Thermally aged Nomex fibres manifest several residual effects viz. reduction in X-ray crystallinity, weight loss and deterioration in tensile characteristics. Surface damages in the form of longi- tudinal openings, holes, material deposits etc have also been observed. Based on the data from thermally exposed fibres ...

  8. Photonic crystal fibres in the market

    DEFF Research Database (Denmark)

    Broeng, Jes; Laurila, Marko; Noordegraaf, Danny

    2011-01-01

    Photonic crystal fibres (PCFs) emerged as a research topic in the mid 1990'ies [1]. Today, 15 years later, these fibres are increasing deployed in various commercial markets. Here, we will address three of these markets; medical imaging, materials processing and sensors. We will describe how the ...

  9. Fibre optic cables for the ALICE experiment

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    These thin fibres will transmit the signal received in detectors at the ALICE experiment when it starts up with the LHC in 2008. The analogue signals produced in the detectors are first converted into digital pulse, which are transported in light down such fibres. Computers then read this digital signal to produce the final set of data.

  10. Eye lens membrane junctional microdomains: a comparison between healthy and pathological cases

    Energy Technology Data Exchange (ETDEWEB)

    Buzhynskyy, Nikolay; Scheuring, Simon [Institut Curie, Equipe Inserm Avenir, UMR168-CNRS, 26 Rue d' Ulm, 75248 Paris Cedex 05 (France); Sens, Pierre [ESPCI, CNRS-UMR 7083, 75231 Paris (France); Behar-Cohen, Francine, E-mail: simon.scheuring@curie.fr [UMRS Inserm 872, Universite Paris Descartes, Centre de Recherches des Cordeliers, 15 rue de l' Ecole de Medecine, 75270 Paris Cedex 06 (France)

    2011-08-15

    The eye lens is a transparent tissue constituted of tightly packed fiber cells. To maintain homeostasis and transparency of the lens, the circulation of water, ions and metabolites is required. Junctional microdomains connect the lens cells and ensure both tight cell-to-cell adhesion and intercellular flow of fluids through a microcirculation system. Here, we overview membrane morphology and tissue functional requirements of the mammalian lens. Atomic force microscopy (AFM) has opened up the possibility of visualizing the junctional microdomains at unprecedented submolecular resolution, revealing the supramolecular assembly of lens-specific aquaporin-0 (AQP0) and connexins (Cx). We compare the membrane protein assembly in healthy lenses with senile and diabetes-II cataract cases and novel data of the lens membranes from a congenital cataract. In the healthy case, AQP0s form characteristic square arrays confined by connexons. In the cases of senile and diabetes-II cataract patients, connexons were degraded, leading to malformation of AQP0 arrays and breakdown of the microcirculation system. In the congenital cataract, connexons are present, indicating probable non-membranous grounds for lens opacification. Further, we discuss the energetic aspects of the membrane organization in junctional microdomains. The AFM hence becomes a biomedical nano-imaging tool for the analysis of single-membrane protein supramolecular association in healthy and pathological membranes.

  11. Eye lens membrane junctional microdomains: a comparison between healthy and pathological cases

    Science.gov (United States)

    Buzhynskyy, Nikolay; Sens, Pierre; Behar-Cohen, Francine; Scheuring, Simon

    2011-08-01

    The eye lens is a transparent tissue constituted of tightly packed fiber cells. To maintain homeostasis and transparency of the lens, the circulation of water, ions and metabolites is required. Junctional microdomains connect the lens cells and ensure both tight cell-to-cell adhesion and intercellular flow of fluids through a microcirculation system. Here, we overview membrane morphology and tissue functional requirements of the mammalian lens. Atomic force microscopy (AFM) has opened up the possibility of visualizing the junctional microdomains at unprecedented submolecular resolution, revealing the supramolecular assembly of lens-specific aquaporin-0 (AQP0) and connexins (Cx). We compare the membrane protein assembly in healthy lenses with senile and diabetes-II cataract cases and novel data of the lens membranes from a congenital cataract. In the healthy case, AQP0s form characteristic square arrays confined by connexons. In the cases of senile and diabetes-II cataract patients, connexons were degraded, leading to malformation of AQP0 arrays and breakdown of the microcirculation system. In the congenital cataract, connexons are present, indicating probable non-membranous grounds for lens opacification. Further, we discuss the energetic aspects of the membrane organization in junctional microdomains. The AFM hence becomes a biomedical nano-imaging tool for the analysis of single-membrane protein supramolecular association in healthy and pathological membranes.

  12. Effect of a 17 day spaceflight on contractile properties of human soleus muscle fibres

    Science.gov (United States)

    Widrick, J. J.; Knuth, S. T.; Norenberg, K. M.; Romatowski, J. G.; Bain, J. L.; Riley, D. A.; Karhanek, M.; Trappe, S. W.; Trappe, T. A.; Costill, D. L.; hide

    1999-01-01

    1. Soleus biopsies were obtained from four male astronauts 45 days before and within 2 h after a 17 day spaceflight. 2. For all astronauts, single chemically skinned post-flight fibres expressing only type I myosin heavy chain (MHC) developed less average peak Ca2+ activated force (Po) during fixed-end contractions (0.78 +/- 0. 02 vs. 0.99 +/- 0.03 mN) and shortened at a greater mean velocity during unloaded contractions (Vo) (0.83 +/- 0.02 vs. 0.64 +/- 0.02 fibre lengths s-1) than pre-flight type I fibres. 3. The flight-induced decline in absolute Po was attributed to reductions in fibre diameter and/or Po per fibre cross-sectional area. Fibres from the astronaut who experienced the greatest relative loss of peak force also displayed a reduction in Ca2+ sensitivity. 4. The elevated Vo of the post-flight slow type I fibres could not be explained by alterations in myosin heavy or light chain composition. One alternative possibility is that the elevated Vo resulted from an increased myofilament lattice spacing. This hypothesis was supported by electron micrographic analysis demonstrating a reduction in thin filament density post-flight. 5. Post-flight fibres shortened at 30 % higher velocities than pre-flight fibres at external loads associated with peak power output. This increase in shortening velocity either reduced (2 astronauts) or prevented (2 astronauts) a post-flight loss in fibre absolute peak power (microN (fibre length) s-1). 6. The changes in soleus fibre diameter and function following spaceflight were similar to those observed after 17 days of bed rest. Although in-flight exercise countermeasures probably reduced the effects of microgravity, the results support the idea that ground-based bed rest can serve as a model of human spaceflight. 7. In conclusion, 17 days of spaceflight decreased force and increased shortening velocity of single Ca2+-activated muscle cells expressing type I MHC. The increase in shortening velocity greatly reduced the impact

  13. A microcapillary lens for X-rays

    CERN Document Server

    Dudchik, Y I

    1999-01-01

    A new design of a compound refractive lens for X-rays is proposed. The lens is made as a set of glue microlenses placed in a glass capillary. The technique of lens fabrication is described. Results of ray tracing calculations for 8 and 15 keV photons are represented.

  14. Non-thermal electromagnetic radiation damage to lens epithelium.

    Science.gov (United States)

    Bormusov, Elvira; P Andley, Usha; Sharon, Naomi; Schächter, Levi; Lahav, Assaf; Dovrat, Ahuva

    2008-05-21

    High frequency microwave electromagnetic radiation from mobile phones and other modern devices has the potential to damage eye tissues, but its effect on the lens epithelium is unknown at present. The objective of this study was to investigate the non-thermal effects of high frequency microwave electromagnetic radiation (1.1GHz, 2.22 mW) on the eye lens epithelium in situ. Bovine lenses were incubated in organ culture at 35°C for 10-15 days. A novel computer-controlled microwave source was used to investigate the effects of microwave radiation on the lenses. 58 lenses were used in this study. The lenses were divided into four groups: (1) Control lenses incubated in organ culture for 10 to15 days. (2) Electromagnetic radiation exposure group treated with 1.1 GHz, 2.22 mW microwave radiation for 90 cycles of 50 minutes irradiation followed by 10 minutes pause and cultured up to 10 days. (3) Electromagnetic radiation exposure group treated as group 2 with 192 cycles of radiation and cultured for 15 days. (4) Lenses exposed to 39.5°C for 2 hours 3 times with 24 hours interval after each treatment beginning on the second day of the culture and cultured for 11 days. During the culture period, lens optical quality was followed daily by a computer-operated scanning laser beam. At the end of the culture period, control and treated lenses were analyzed morphologically and by assessment of the lens epithelial ATPase activity. Exposure to 1.1 GHz, 2.22 mW microwaves caused a reversible decrease in lens optical quality accompanied by irreversible morphological and biochemical damage to the lens epithelial cell layer. The effect of the electromagnetic radiation on the lens epithelium was remarkably different from those of conductive heat. The results of this investigation showed that electromagnetic fields from microwave radiation have a negative impact on the eye lens. The lens damage by electromagnetic fields was distinctly different from that caused by conductive heat.

  15. Insulation Characteristics of Sisal Fibre/Epoxy Composites

    Directory of Open Access Journals (Sweden)

    A. Shalwan

    2017-01-01

    Full Text Available Using natural fibres in civil engineering is the aim of many industrial and academics sectors to overcome the impact of synthetic fibres on environments. One of the potential applications of natural fibres composites is to be implemented in insulation components. Thermal behaviour of polymer composites based on natural fibres is recent ongoing research. In this article, thermal characteristics of sisal fibre reinforced epoxy composites are evaluated for treated and untreated fibres considering different volume fractions of 0–30%. The results revealed that the increase in the fibre volume fraction increased the insulation performance of the composites for both treated and untreated fibres. More than 200% insulation rate was achieved at the volume fraction of 20% of treated sisal fibres. Untreated fibres showed about 400% insulation rate; however, it is not recommended to use untreated fibres from mechanical point of view. The results indicated that there is potential of using the developed composites for insulation purposes.

  16. Review article: dietary fibre-microbiota interactions.

    Science.gov (United States)

    Simpson, H L; Campbell, B J

    2015-07-01

    Application of modern rapid DNA sequencing technology has transformed our understanding of the gut microbiota. Diet, in particular plant-based fibre, appears critical in influencing the composition and metabolic activity of the microbiome, determining levels of short-chain fatty acids (SCFAs) important for intestinal health. To assess current epidemiological, experimental and clinical evidence of how long-term and short-term alterations in dietary fibre intake impact on the microbiome and metabolome. A Medline search including items 'intestinal microbiota', 'nutrition', 'diet', 'dietary fibre', 'SCFAs' and 'prebiotic effect' was performed. Studies found evidence of fibre-influenced differences in the microbiome and metabolome as a consequence of habitual diet, and of long-term or short-term intervention (in both animals and humans). Agrarian diets high in fruit/legume fibre are associated with greater microbial diversity and a predominance of Prevotella over Bacteroides. 'Western'-style diets, high in fat/sugar, low in fibre, decrease beneficial Firmicutes that metabolise dietary plant-derived polysaccharides to SCFAs and increase mucosa-associated Proteobacteria (including enteric pathogens). Short-term diets can also have major effects, particularly those exclusively animal-based, and those high-protein, low-fermentable carbohydrate/fibre 'weight-loss' diets, increasing the abundance of Bacteroides and lowering Firmicutes, with long-term adherence to such diets likely increasing risk of colonic disease. Interventions to prevent intestinal inflammation may be achieved with fermentable prebiotic fibres that enhance beneficial Bifidobacteria or with soluble fibres that block bacterial-epithelial adherence (contrabiotics). These mechanisms may explain many of the differences in microbiota associated with long-term ingestion of a diet rich in fruit and vegetable fibre. © 2015 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.

  17. Hyperbolic metamaterial lens with hydrodynamic nonlocal response

    DEFF Research Database (Denmark)

    Yan, Wei; Mortensen, N. Asger; Wubs, Martijn

    2013-01-01

    We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves of the f......We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves...... in the local-response approximation and in the hydrodynamic Drude model can differ considerably. In particular, the optimal frequency for imaging in the nonlocal theory is blueshifted with respect to that in the local theory. Thus, to detect whether nonlocal response is at work in a hyperbolic metamaterial, we...... propose to measure the near-field distribution of a hyperbolic metamaterial lens....

  18. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  19. ECTOPIC LENS EXTRACTION IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2002-12-01

    Full Text Available Background. Ectopia lentis continues to be a therapeutic challenge for ophthalmologists. It can occur as an isolated condition, after ocular trauma, in association with other ocular disorders, as part of a systemic mesodermal disease or a complication of general metabolic disorders. Minimal subluxation of the lens may cause no visual symptoms, but in more advanced cases serious optical disturbances arise. The most important is amblyopia. Surgical treatment options include iris manipulation, lens discission, aspiration, intracapsular or extracapsular extraction, and pars plana lensectomy. The choice of surgical technique remains controversial, in part because of the historically poor visual results and high rate of perioperative complications, including vitreous loss and retinal detachment.Methods. We describe a surgical technique based on the use of the Cionni endocapsular tension ring, dry irrigation aspiration of lens material, centration of the capsular bag and foldable intraocular lens implantation into the bag. With mentioned surgical technique 8 patients were operated; 4 boys and 4 girls, together 11 eyes.Results. The final BCVA after follow up period improved in 9 eyes and it remained the same as before operation in one eye. Statistical comparison of preoperative and postoperative visual acuities showed significant improvement. On the other hand there was no correlation between preoperative and postoperative visual acuity.Conclusions. This surgical procedure is an alternative approach in solving this challenging cases of ectopia lentis with good postoperative visual rehabilitation.

  20. Spinning pipe gas lens revisited

    CSIR Research Space (South Africa)

    Mafusire, C

    2008-01-01

    Full Text Available , there is little information on optical phase aberrations and no study to date on the propagation parameters of the laser beam, but has rather remained rooted in the domain of ray optics. Researchers revisit the spinning pipe gas lens in this paper with new...

  1. Tube entrance lens focus control

    Science.gov (United States)

    Weisser, D. C.; Fifield, L. K.; Kitchen, T. F. G.; Tunningley, T. B.; Lobanov, N. R.; Muirhead, A. G.

    2013-02-01

    The entrance of the accelerator tube in a large electrostatic accelerator imposes a strong lens that dominates the beam optics. The magnification of the lens is large because of the low injection energy, the high voltage gradient of the acceleration tube and the long distance to the terminal. In the absence of the acceleration, the magnification would produce an unacceptably large beam spot at the terminal. The tyranny of the lens is especially irksome when the accelerator is required to operate at a lower terminal voltage than the one corresponding to the nominal gradient at high voltage. One way around the difficulty, used in NEC Pelletron accelerators, is to insert a series of nylon and steel rods that short together units of the acceleration structure at the terminal leaving the ones near the entrance close to the nominal gradient for optimum transmission. This operation takes time and risks the loss of insulating gas. Another alternative used in the 25URC at Oak Ridge National Laboratory, is to focus the beam at the tube entrance, substantially diluting the effect of the entrance lens. The beam then diverges and so requires an additional lens part way to the terminal. This solution is only partially effective and still necessitates use of shorting rods for low voltage operation. The fact that these elaborate strategies are used is evidence that the alternative of lowering the injection energy as the terminal voltage is lowered imposes enough problems that it is not used in practice. We have modeled a solution that controls the voltage gradient at the tube entrance using an external power supply. This not only maintains the focusing effect of the lens but provides the opportunity to tune the beam by adjusting the entrance lens. A 150 kV power supply outside the pressure vessel feeds a controllable voltage through a high voltage feed-through to the fifth electrode of the accelerator tube. Thus 150 kV on this electrode creates the nominal gradient of 30 kV per

  2. Lens regeneration in juvenile and adult rabbits measured by image analysis.

    Science.gov (United States)

    Gwon, A E; Jones, R L; Gruber, L J; Mantras, C

    1992-06-01

    Secondary cataract growth commonly occurs after extracapsular cataract extraction. The proliferation of this regrowth occurs at rates related to many factors. In this study, the authors analyzed the amount of lens regeneration after endocapsular lens extraction that leaves the anterior and posterior capsules relatively intact. The analysis was performed in New Zealand albino rabbits with the aid of image analysis measurements in young and adult animals. The effect of low vacuum suction of the anterior capsule on the growth was determined. Lens regeneration was used as a measure of the growth potential of the leftover epithelial cells in the capsule bag. The results showed that lens regeneration was significantly faster in younger rabbits. However, low vacuum suction had no effect on the growth rate. Potential therapeutic agents for preventing secondary cataracts may be better analyzed with image analysis processing of lens regeneration, a precise and rapid measurement technique.

  3. Purines in the eye: recent evidence for the physiological and pathological role of purines in the RPE, retinal neurons, astrocytes, Müller cells, lens, trabecular meshwork, cornea and lacrimal gland.

    Science.gov (United States)

    Sanderson, Julie; Dartt, Darlene A; Trinkaus-Randall, Vickery; Pintor, Jesus; Civan, Mortimer M; Delamere, Nicholas A; Fletcher, Erica L; Salt, Thomas E; Grosche, Antje; Mitchell, Claire H

    2014-10-01

    This review highlights recent findings that describ how purines modulate the physiological and pathophysiological responses of ocular tissues. For example, in lacrimal glands the cross-talk between P2X7 receptors and both M3 muscarinic receptors and α1D-adrenergic receptors can influence tear secretion. In the cornea, purines lead to post-translational modification of EGFR and structural proteins that participate in wound repair in the epithelium and influence the expression of matrix proteins in the stroma. Purines act at receptors on both the trabecular meshwork and ciliary epithelium to modulate intraocular pressure (IOP); ATP-release pathways of inflow and outflow cells differ, possibly permitting differential modulation of adenosine delivery. Modulators of trabecular meshwork cell ATP release include cell volume, stretch, extracellular Ca(2+) concentration, oxidation state, actin remodeling and possibly endogenous cardiotonic steroids. In the lens, osmotic stress leads to ATP release following TRPV4 activation upstream of hemichannel opening. In the anterior eye, diadenosine polyphosphates such as Ap4A act at P2 receptors to modulate the rate and composition of tear secretion, impact corneal wound healing and lower IOP. The Gq11-coupled P2Y1-receptor contributes to volume control in Müller cells and thus the retina. P2X receptors are expressed in neurons in the inner and outer retina and contribute to visual processing as well as the demise of retinal ganglion cells. In RPE cells, the balance between extracellular ATP and adenosine may modulate lysosomal pH and the rate of lipofuscin formation. In optic nerve head astrocytes, mechanosensitive ATP release via pannexin hemichannels, coupled with stretch-dependent upregulation of pannexins, provides a mechanism for ATP signaling in chronic glaucoma. With so many receptors linked to divergent functions throughout the eye, ensuring the transmitters remain local and stimulation is restricted to the intended target

  4. Vegetable fibres from agricultural residues as thermo-mechanical reinforcement in recycled polypropylene-based green foams.

    Science.gov (United States)

    Ardanuy, Mònica; Antunes, Marcelo; Velasco, José Ignacio

    2012-02-01

    Novel lightweight composite foams based on recycled polypropylene reinforced with cellulosic fibres obtained from agricultural residues were prepared and characterized. These composites, initially prepared by melt-mixing recycled polypropylene with variable fibre concentrations (10-25 wt.%), were foamed by high-pressure CO(2) dissolution, a clean process which avoids the use of chemical blowing agents. With the aim of studying the influence of the fibre characteristics on the resultant foams, two chemical treatments were applied to the barley straw in order to increase the α-cellulose content of the fibres. The chemical composition, morphology and thermal stability of the fibres and composites were analyzed. Results indicate that fibre chemical treatment and later foaming of the composites resulted in foams with characteristic closed-cell microcellular structures, their specific storage modulus significantly increasing due to the higher stiffness of the fibres. The addition of the fibres also resulted in an increase in the glass transition temperature of PP in both the solid composites and more significantly in the foams. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

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

    Science.gov (United States)

    Pathi, Sridhar; Jayaraman, Krishnan

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

  7. Influence of Cellulosic Fibres on the Physical Properties of Fibre Cement Composites

    Science.gov (United States)

    Hospodarova, V.; Stevulova, N.; Vaclavik, V.; Dvorsky, T.

    2017-10-01

    Nowadays, there are new approaches directing to processing of non-conventional fibre-cement composites for application in the housing construction. Vegetable cellulosic fibres coming from natural resources used as reinforcement in cost-effective and environmental friendly building products are in the spotlight. The applying of natural fibres in cement based composites is narrowly linked to the ecological building sector, where a choice of materials is based on components including recyclable, renewable raw materials and low-resource manufacture techniques. In this paper, two types of cellulosic fibres coming from wood pulp and recycled waste paper with 0.2%; 0.3% and 0.5% of fibre addition into cement mixtures were used. Differences in the physical characteristics (flowability, density, coefficient of thermal conductivity and water absorbability) of 28 days hardened fibre-cement composites are investigated. Addition of cellulosic fibres to cement mixture caused worsening the workability of fresh mixture as well as absorbability of hardened composites due to hydrophilic nature of biomaterial, whereas density and thermal conductivity of manufactured cement based fibre plaster are enhanced. The physical properties of cement plasters based on cellulosic fibres depend on structural, physical characteristics of cellulosic fibres, their nature and processing.

  8. Design of Novel Compound Fresnel Lens for High-Performance Photovoltaic Concentrator

    Directory of Open Access Journals (Sweden)

    Lei Jing

    2012-01-01

    Full Text Available We present a new design of compound Fresnel-R concentrator which is composed of two lenses: a primary lens (Fresnel lens that works by total internal reflection at outer sawteeth but refraction at inner sawteeth, and a ringed secondary lens that works by refraction. In contrast to previous Fresnel lens concentrators, this design increases the acceptance angle, improves the irradiance uniformity on the solar cell, and reduces the aspect ratio significantly. Meanwhile several sawteeth of the primary Fresnel lens can correspond to a same ring of secondary lens, which will efficiently lower the complexity of designing and manufacturing. Moreover, in order to reduce the influence of manufacturing tolerances and to increase the optical efficiency further, the central part of the bottom of the secondary lens which directly adhered to the solar cell is designed as a cone-shaped prism to collect the sunlight that does not reach the solar cell. Finally, we provide simulations and analyses of the design method an optical efficiency more than 80% and an aspect ratio smaller than 0.5 can be achieved.

  9. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Shin, Jung Hyuck; Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin

    2011-01-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility

  10. Lens decenter and tilt measurement by interferogram

    Science.gov (United States)

    Hung, Min-Wei; Wu, Wen-Hong; Huang, Kuo-Cheng

    2009-11-01

    For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.

  11. Ceramic fibres for the automotive industry

    Energy Technology Data Exchange (ETDEWEB)

    Fryatt, J.

    1985-01-01

    The outstanding thermal, physical and chemical properties of ceramic fibres make them a noticeable contender for inclusion in engineered systems to satisfy such performance demands. A wide range of fibres and fibre-based products are available which exhibit such characteristics as high temperature continuous service ability (1600/sup 0/C if required), low thermal conductivity, excellent resistance to chemical attack (including reducing conditions), good acoustic performance at all temperatures and good resistance to vibration. They are also lightweight, fireproof and incombustible. Ceramic fibres should really be referred to as refractory fibres as they are based on combinations of high purity alumina and silica. Two groups of products exist. The most common have a continuous-use temperature of 1260/sup 0/C. These fibres are characterized by an alumina content of 40-50% but refractoriness and temperature use limit can be increased to about 1400/sup 0/C by modifying the basic chemistry. This generally involves increasing the alumina content to as much as 62% or adding chromia or zirconia to the basic mix. The second and less common group of fibres is characterized by both chemistry and crystal morphology. Chemistry is biased towards a high alumina content (over 70%), while production routes are designed to yield as high a crystal phase (and so enhanced high temperature stability) as possible.

  12. Oxidation of lignin in hemp fibres by laccase: effects on mechanical properties of hemp fibres and unidirectional fibre/epoxy composites

    DEFF Research Database (Denmark)

    Liu, Ming; Baum, Andreas; Odermatt, Jürgen

    2017-01-01

    Laccase activity catalyzes oxidation and polymerization of phenols. The effect of laccase treatment on the mechanical properties of hemp fibres and hemp fibre/epoxy composites was examined. Laccase treatment on top of 0.5% EDTA + 0.2% endo-polygalacturonase (EPG) treatments increased the mechanical...... properties of hemp fibres and fibre/epoxy composites. Comparing all fibre treatments, composites with 0.5% EDTA + 0.2% EPG + 0.5% laccase treated fibres had highest stiffness of 42 GPa and highest ultimate tensile strength (UTS) of 326 MPa at a fibre volume content of 50%. The thermal resistance of hemp...... hemp fibres and their composites were due to laccase catalyzed polymerization of lignin moieties in hemp fibres....

  13. Changes of enzyme activities in lens after glaucoma trabecular resection

    Directory of Open Access Journals (Sweden)

    Jian-Ping Wang

    2013-08-01

    Full Text Available AIM: To observe the change of lens antioxidant enzyme activity after glaucoma trabecular resection. METHODS: Thirty-two eyes of sixteen New-Zealand rabbits(2.2-2.4kgwere divided into two groups. The left eyes of rabbits underwent standard glaucoma trabecular resection were treatment group, and the normal right eyes served as controls. Transparency of lenses was monitored by a slit-lamp biomicroscopy before and after glaucoma trabecular resection. The morphology of lens cells was observed under the light microscope.The activities of Na+-K+-ATPase,catalase(CAT, glutathion peroxidase(GSH-px, glutathione reductase(GR, superoxide dismutase(SODand content of malondialdehyde(MDAin lenses were detected six months after trabecular resection. RESULTS: Lenses were clear in both treatment group and normal control group during the six months after operation. The morphology and structure of lens cells were normal under the light microscope in both operation group and normal group. The activity of lens cells antioxidant enzyme activity were significantly decreased in operation group compared with control group, Na+-K+-ATPase declined by 20.97%, CAT declined by 16.36%, SOD declined by 4.46%, GR declined by 4.85%, GSH-px declined by 10.02%, and MDA increased by 16.31%. CONCLUSION: Glaucoma trabecular resection can induce the change of Na+-K+-ATPase, CAT, GSH-px, GR, SOD and MDA in lens of rabbit. Glaucoma filtration surgery for the occurrence of cataract development mechanism has important guiding significance.

  14. Degradation of dietary fibre from 'Gari' by faecal bacteria and ...

    African Journals Online (AJOL)

    Dietary fibre (soluble and insoluble fibre) was extracted from 'gari' (a fermented cassava product). The 'gari' fibre was subjected to degradation by faecal microflora and the microbial extracellular enzymes obtained from six clinically healthy adults (S1-S6). Other common components of dietary fibre namely starch, xylan, ...

  15. Effects of moisture on the mechanical properties of glass fibre ...

    Indian Academy of Sciences (India)

    Unknown

    SEM study of the fractured surfaces showed heavy fibre pull-out in the tensile zone whilst shear fracture of the fibre bundles was predominant at the compressive zone of the samples tested for flexural strength properties. Keywords. Nascent glass fibre; vinylester resin; moisture effects; fibre pull-out. 1. Introduction. Over the ...

  16. Assessment of Fibre Characteristics and Suitability of Maize Husk ...

    African Journals Online (AJOL)

    Maize husk and stalk were assessed for their fibre characteristics and suitability for pulp and paper production. Fifteen (15) fibres were randomly selected and measured from each representative sample. It was observed that fibre length of maize husk was 1.37mm and that of maize stalk was 1.52mm. The fibre diameter (D) ...

  17. Mechanical properties of natural fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    Wintec

    green composites involving Hibiscus sabdariffa fibre as a reinforcing material in urea–formaldehyde (UF) resin based polymer ... mixed Hibiscus sabdariffa fibre reinforced polymer composites such as tensile, compressive and wear proper- ties were ... in natural fibres and its applications in various fields. Natural fibres are ...

  18. Mechanical properties of natural fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    Wintec

    forcing materials such as glass fibre, carbon fibre etc are their specific ... this is the substitution of inorganic fibres such as glass or aramid fibres by .... friction. The samples were tested with different loads vary- ing from 1–3 kg. For each load the machine was allowed to run for 15 min and the readings were recorded. After.

  19. Dietary fibre: new frontiers for food and health

    National Research Council Canada - National Science Library

    Kamp, J. W. van der

    2010-01-01

    ... papers of the Dietary fibre analysis workshop and the HEALTHGRAIN Symposium Cereal grain fibre and health , both held in conjunction with DF09. This book is titled Dietary fibre- new frontiers for food and health . With the adoption - after decades of debate - of almost identical definitions of dietary fibre by Codex Alimentarius and the European Un...

  20. Comparison of two novel approaches to model fibre reinforced concrete

    NARCIS (Netherlands)

    Radtke, F.K.F.; Simone, A.; Sluys, L.J.

    2009-01-01

    We present two approaches to model fibre reinforced concrete. In both approaches, discrete fibre distributions and the behaviour of the fibre-matrix interface are explicitly considered. One approach employs the reaction forces from fibre to matrix while the other is based on the partition of unity

  1. Enhancement of Short Chain Fatty Acid Production from Millet Fibres ...

    African Journals Online (AJOL)

    Dietary fibre was extracted from two millet varieties viz Pearl millet, Pennisetum glaucum (PM) and Foxtail millet (FxM, Setaria italica), and separated into total dietary fibre (TDF), insoluble dietary fibre (IDF) and soluble dietary fibre (SDF). Four probiotic bacteria (Lactobacillus rhamnosus, Lactobacillus acidophilus, ...

  2. factors that improve the impact responses of ukam plant fibre ...

    African Journals Online (AJOL)

    mat, woven rovings, surface tissues, continu- ous strand mat and woven cloth webbing. In fibre reinforced composites, high- strength fibres are incased within a tough ma- trix. The functions of the matrix are to bond the fibres together, protect them against dam- ages and transmit load from fibre to another. According to Harris ...

  3. Plant fibre composites - porosity and stiffness

    DEFF Research Database (Denmark)

    Madsen, Bo; Thygesen, Anders; Lilholt, Hans

    2009-01-01

    of the composites with their mechanical properties. The fibre weight fraction is used as an independent parameter to calculate the complete volumetric composition. A maximum obtainable stiffness of the composites is calculated at a certain transition fibre weight fraction, which is characterised by a best possible...... combination of high fibre volume fraction and low porosity. The model is validated with experimental data from the literature on several types of composites. A stiffness diagram is presented to demonstrate that the calculations can be used for tailoring and design of composites with a given profile...... of properties. (C) 2009 Elsevier Ltd. All rights reserved....

  4. Higher order modes of coupled optical fibres

    International Nuclear Information System (INIS)

    Alexeyev, C N; Yavorsky, M A; Boklag, N A

    2010-01-01

    The structure of hybrid higher order modes of two coupled weakly guiding identical optical fibres is studied. On the basis of perturbation theory with degeneracy for the vector wave equation expressions for modes with azimuthal angular number l ≥ 1 are obtained that allow for the spin–orbit interaction. The spectra of polarization corrections to the scalar propagation constants are calculated in a wide range of distances between the fibres. The limiting cases of widely and closely spaced fibres are studied. The obtained results can be used for studying the tunnelling of optical vortices in directional couplers and in matters concerned with information security

  5. A target fibre study on seats in public houses.

    Science.gov (United States)

    Kelly, E; Griffin, R M

    1998-01-01

    A target fibre survey was conducted to assess the random occurrence of a blue wool fibre on seats in public houses throughout the United Kingdom. Fibre tape lifts were taken from 80 seats. Four seats yielded matching fibres and five of these were found on one seat. A total of 292 fibres were identified; nine fibres proved indistinguishable from the target after comparison microscopy, microspectro-photometry and attempts at thin layer chromatography, and two of these fibres were still apparently indistinguishable after TLC analysis although only one dye component was visible.

  6. Inhibition of starch absorption by dietary fibre. A comparative study of wheat bran, sugar-beet fibre, and pea fibre

    DEFF Research Database (Denmark)

    Hamberg, O; Rumessen, J J; Gudmand-Høyer, E

    1989-01-01

    The effect of dietary fibre on starch absorption was investigated in 8 healthy subjects. Amounts of starch escaping small-bowel absorption was assessed by comparison of breath H2 excretion after test meals and after lactulose (10g). After ingestion of bread made from 100g of wheat flour increases...... that the dietary fibres used in this impaired the absorption of wheat starch and thereby increased the amount of starch-derived carbohydrate available for colonic fermentation....... in H2 excretion occurred in all subjects; the calculated fractions of unabsorbed starch ranged from 4% to 17% (median, 8%). Concurrent ingestion of this bread with either wheat bran, sugar-beet fibre, or pea fibre increased the fraction of unabsorbed starch to 12.5% (5-22%) (p less than 0.05), 12.5% (5...

  7. Fibre Bragg Grating and Long Period Grating Sensors in Polymer Optical Fibres

    OpenAIRE

    Bundalo, Ivan-Lazar; Bang, Ole; Nielsen, Kristian

    2017-01-01

    The work presented in this thesis focuses on improving the fabrication of Fibre Bragg Gratings (FBGs) and Long Period Gratings (LPGs) in microstructure polymer optical fibres (mPOF). It also focuses on exploring new options for biomedical and acoustic sensing with the purpose of expanding the range of applications and pushing the limits. The first part of the work focuses on the fabrication of FBGs in polymer optical fibres. FBGs are a periodic perturbation of the refractive index of the opti...

  8. Hybrid RSOA and fibre raman amplified long reach feeder link for WiMAX-on-fibre

    DEFF Research Database (Denmark)

    Amaya Fernández, Ferney Orlando; Martinez, Javier; Yu, Xianbin

    2009-01-01

    A distributed fibre Raman amplified long reach optical access feeder link using a reflective semiconductor optical amplifier in the remote base station is experimentally demonstrated for supporting WiMAXover- fibre transmission. The measured values for the error vector magnitude for quadrature ph...... phase shift keying and 16-ary quadrature amplitude modulation after 40 km of fibre transmission meet the IEEE 820.16 standard requirements...

  9. Shrinkage Behaviour of Fibre Reinforced Concrete with Recycled Tyre Polymer Fibres

    OpenAIRE

    Marijana Serdar; Ana Baričević; Marija Jelčić Rukavina; Martina Pezer; Dubravka Bjegović; Nina Štirmer

    2015-01-01

    Different types of fibres are often used in concrete to prevent microcracking due to shrinkage, and polypropylene fibres are among the most often used ones. If not prevented, microcracks can lead to the development of larger cracks as drying shrinkage occurs, enabling penetration of aggressive substances from the environment and reducing durability of concrete structures. The hypothesis of the present research is that polypropylene fibres, used in concrete for controlling formation of microcr...

  10. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Sriram Krishnamurthy

    2016-05-01

    Full Text Available Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from −600 µε (conventional processing without pre-stress to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to “neutralising” the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E

  11. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors.

    Science.gov (United States)

    Krishnamurthy, Sriram; Badcock, Rodney A; Machavaram, Venkata R; Fernando, Gerard F

    2016-05-28

    Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from -600 µε (conventional processing without pre-stress) to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to "neutralising" the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E-glass composites.

  12. Looking beyond the perfect lens

    International Nuclear Information System (INIS)

    Wee, W H; Pendry, J B

    2010-01-01

    The holy grail of imaging is the ability to see through anything. From the conservation of energy, we can easily see that to see through a lossy material would require lenses with gain. The aim of this paper therefore is to propose a simple scheme by which we can construct a general perfect lens, with gain-one that can restore both the phases and amplitudes of near and far fields.

  13. Compression moulding of composites with hybrid fibre architectures

    OpenAIRE

    Corbridge, D.M.; Harper, Lee Thomas; De Focatiis, Davide S.A.; Warrior, N.A.

    2016-01-01

    Advanced Sheet Moulding Compounds (ASMC) and unidirectional (UD) prepregs have been co-compression moulded to form a hybrid composite material. In-mould flow influences the UD fibre architecture in two ways. When UD fibres are aligned transversely to the ASMC flow direction, shearing occurs which causes local changes in fibre volume fraction and fibre waviness. When the UD fibres are aligned with the ASMC flow direction, ply migration takes place. In general, the composite stiffness follows a...

  14. Extraction of lotus fibres from lotus stems under microwave irradiation

    OpenAIRE

    Cheng, Cheng; Guo, Ronghui; Lan, Jianwu; Jiang, Shouxiang

    2017-01-01

    An efficient technology for preparing lotus fibres under microwave irradiation was developed. The lotus fibres were characterized by scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction and thermogravimetry. Lotus fibres prepared are a kind of hollow fibres which are composed of a superfine fibre and an external shell. The effect of the treatment time with hydrogen peroxide under microwave irradiation on components, whiteness, moisture regain, removal rate ...

  15. DESIGN OF COMPOSITION OF CONCRETE USING POLYPROPYLENE FIBRE REINFORCEMENT

    OpenAIRE

    Dang Van Thanh1,*, Vu Hoang Hiep2, Nguyen Van Bac1, Hoang Gia Duong1

    2016-01-01

    Fibre-reinforced concrete is an emerging trend that delivers new materials with high quality for construction. Polyporpylene fibre, an organic textile, has high potential to be used for reinforcing concrete, but there has been little research conducted into using this fibre for concrete reinforcement worldwide and no research work on this fibre reinforced concrete has been published in Vietnam. Thereofore, researchinginto Polyporylene fibre reinforced concrete to establish fundamental underst...

  16. Biological durability and oxidative potential of a stonewool mineral fibre compared to crocidolite asbestos fibres

    Energy Technology Data Exchange (ETDEWEB)

    Hippeli, S. [Lehrstuhl fuer Phytopathologie, Labor fuer Biochemische Toxikologie, Technische Universitaet Muenchen-Weihenstephan, D-85350 Freising-Weihenstephan (Germany); Dornisch, K. [Lehrstuhl fuer Phytopathologie, Labor fuer Biochemische Toxikologie, Technische Universitaet Muenchen-Weihenstephan, D-85350 Freising-Weihenstephan (Germany); Kaiser, S. [Lehrstuhl fuer Phytopathologie, Labor fuer Biochemische Toxikologie, Technische Universitaet Muenchen-Weihenstephan, D-85350 Freising-Weihenstephan (Germany); Draeger, U. [Deutsche Rockwool Mineralwoll GmbH, Karl-Schneider-Strasse 14-18, D-45966 Gladbeck (Germany); Elstner, E.F. [Lehrstuhl fuer Phytopathologie, Labor fuer Biochemische Toxikologie, Technische Universitaet Muenchen-Weihenstephan, D-85350 Freising-Weihenstephan (Germany)

    1997-07-01

    Experiments are described concerning the differences in redox properties and biodurability of natural asbestos fibres and an experimental stonewool fibre incubated in Gamble solution and reconstructed surfactant fluid. Crocidolite exhibits a significantly higher oxidative potential compared to the tested stonewool fibres. The oxidative acitivity of both types of fibres is not constant during incubation over several weeks, but rather shows a sinoidal curve including reactivities much higher than those at the beginning of the incubation. A continuous loss of mass is concluded not to be definitively connected with a continuous loss of toxicity. (orig.). With 1 fig.

  17. Shrinkage Behaviour of Fibre Reinforced Concrete with Recycled Tyre Polymer Fibres

    Directory of Open Access Journals (Sweden)

    Marijana Serdar

    2015-01-01

    Full Text Available Different types of fibres are often used in concrete to prevent microcracking due to shrinkage, and polypropylene fibres are among the most often used ones. If not prevented, microcracks can lead to the development of larger cracks as drying shrinkage occurs, enabling penetration of aggressive substances from the environment and reducing durability of concrete structures. The hypothesis of the present research is that polypropylene fibres, used in concrete for controlling formation of microcracks due to shrinkage, can be replaced with recycled polymer fibres obtained from end-of-life tyres. To test the hypothesis, concrete mixtures containing polypropylene fibres and recycled tyre polymer fibres were prepared and tested. Experimental programme focused on autogenous, free, and restrained shrinkage. It was shown that PP fibres can be substituted with higher amount of recycled tyre polymer fibres obtaining concrete with similar shrinkage behaviour. The results indicate promising possibilities of using recycled tyre polymer fibres in concrete products. At the same time, such applications would contribute to solving the problem of waste tyre disposal.

  18. CONTACT LENS RELATED CORNEAL ULCER

    Directory of Open Access Journals (Sweden)

    AGARWAL P

    2010-01-01

    Full Text Available A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are:overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. The presenting symptoms of contact lens related corneal ulcers include eye discomfort, foreign body sensation and lacrimation. More serious symptoms are redness (especially circum-corneal injection, severe pain, photophobia, eye discharge and blurring of vision. The diagnosis is established by a thorough slit lamp microscopic examination with fluorescein staining and corneal scraping for Gram stain and culture of the infective organism. Delay in diagnosing and treatment can cause permanent blindness, therefore an early referral to ophthalmologist and commencing of antimicrobial therapy can prevent visual loss.

  19. Individual fibre segmentation from 3D X-ray computed tomography for characterising the fibre orientation in unidirectional composite materials

    DEFF Research Database (Denmark)

    Emerson, Monica Jane; Jespersen, Kristine Munk; Dahl, Anders Bjorholm

    2017-01-01

    The aim of this paper is to characterise the fibre orientation in unidirectional fibre reinforced polymers, namely glass and carbon fibre composites. The compression strength of the composite is related to the orientation of the fibres. Thus the orientation is essential when designing materials...... for wind turbine blades. The calculation of the fibre orientation distribution is based on segmenting the individual fibres from volumes that have been acquired through X-ray tomography. The segmentation method presented in this study can accurately extract individual fibres from low contrast X-ray scans...... of composites with high fibre volume fraction. From the individual fibre orientations, it is possible to obtain results which are independent of the scanning quality. The compression strength for both composites is estimated from the average fibre orientations and is found to be of the same order of magnitude...

  20. Optical Fibre Pressure Sensors in Medical Applications

    Directory of Open Access Journals (Sweden)

    Sven Poeggel

    2015-07-01

    Full Text Available This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

  1. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Nielsen, Laila

    1997-01-01

    (capillary water uptake) is used, involving an in-situ method and a laboratory method. Three different concrete qualities as well as steel fibres (ZP) and polypropylene fibres (PP) are used. Results of the durability tests on cracked FRC-beams are compared to results for uncracked FRC-beams and beams without......Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by exposing beams to il-point bending until a predefined crack width is reached, using a newly developed test setup. As environmental load, exposure to water...... fibres and the influence of fibres and cracks on the water uptake is discussed....

  2. Central Tracking Detector Based on Scintillating Fibres

    CERN Multimedia

    2002-01-01

    Scintillating fibres form a reasonable compromise for central tracking detectors in terms of price, resolution, response time, occupancy and heat production. \\\\ \\\\ New fluorescents with large Stokes shifts have been produced, capable of working without wavelength shifters. Coherent multibundles have been developed to achieve high packing fractions. Small segments of tracker shell have been assembled and beam tests have confirmed expectations on spatial resolution. An opto-electronic delay line has been designed to delay the track patterns and enable coincidences with a first level trigger. Replacement of the conventional phosphor screen anode with a Si pixel chip is achieved. This tube is called ISPA-tube and has already been operated in beam tests with a scintillating fibres tracker. \\\\ \\\\ The aim of the proposal is to improve hit densities for small diameter fibres by increasing the fraction of trapped light, by reducing absorption and reflection losses, by reflecting light at the free fibre end, and by inc...

  3. Interfaces between a fibre and its matrix

    DEFF Research Database (Denmark)

    Lilholt, Hans; Sørensen, Bent F.

    2017-01-01

    parameters (applied load, debond length and relative fibre/matrix displacement) are rather similar for these test modes. A simplified analysis allows the direct determination of the three interface parameters from two plots for the experimental data. The complete analysis is demonstrated for steel fibres...... in polyester matrix. The analysis of existing experimental literature data is demonstrated for steel fibres in epoxy matrix and for tungsten wires in copper matrix. These latter incomplete analyses show that some results can be obtained even if all three experimental parameters are not recorded.......The interface between a fibre and its matrix represents an important element in the characterization and exploitation of composite materials. Both theoretical models and analyses of experimental data have been presented in the literature since modern composite were developed and many experiments...

  4. Shielding properties of fibre cement wallboard.

    Science.gov (United States)

    Thiele, D L; Godwin, G A; Coakley, K S

    1998-09-01

    Transmission data for a fibre cement wallboard (villaboard) are determined for use in diagnostic shielding designs. Villaboard is found to be more attenuating than plasterboard e.g. 9 mm of villaboard is equivalent to 16 mm of plasterboard.

  5. Optical Fibre Pressure Sensors in Medical Applications.

    Science.gov (United States)

    Poeggel, Sven; Tosi, Daniele; Duraibabu, DineshBabu; Leen, Gabriel; McGrath, Deirdre; Lewis, Elfed

    2015-07-15

    This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

  6. Radiation-resistant fibre for particle accelerator

    CERN Multimedia

    2007-01-01

    "Radiation-resistant optical fibre is being used by CERN, the European Laboratory for Particle Physics, in the world's largest particle accelerator, the Large Hadron Collider (LHC) near Geneva." (1 page)

  7. Optical fibres bringing the LHC into focus

    CERN Multimedia

    2003-01-01

    New components are being added to CERN's optical fibre network, which will transport the torrents of data produced by the LHC. 1500 kilometres of cables will be installed in the tunnels and at ground level.

  8. Force focusing in confined fibres and sheets

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Victor; Cerda, Enrique [Departamento de Fisica, Universidad de Santiago, Av. Ecuador 3493, Santiago (Chile); Witten, T A; Liang Tao [James Franck Institute, University of Chicago, Chicago IL 60637 (United States)], E-mail: t-witten@uchicago.edu

    2008-07-07

    A thin fibre or sheet curled into a circular container has a detached region whose shape and force ratios are independent of material properties and container radius. We compute this shape and compare it with experiments. The discrete forces acting at either end of the detached region have a ratio that depends only on the length of the fibre or sheet relative to the circle radius. We calculate this force ratio in three regimes of circle radius. (fast track communication)

  9. Tissue elasticity and the ageing elastic fibre

    OpenAIRE

    Sherratt, Michael J.

    2009-01-01

    The ability of elastic tissues to deform under physiological forces and to subsequently release stored energy to drive passive recoil is vital to the function of many dynamic tissues. Within vertebrates, elastic fibres allow arteries and lungs to expand and contract, thus controlling variations in blood pressure and returning the pulmonary system to a resting state. Elastic fibres are composite structures composed of a cross-linked elastin core and an outer layer of fibrillin microfibrils. Th...

  10. Dynamic response analysis of DFB fibre lasers

    DEFF Research Database (Denmark)

    Yujun, Qian; Varming, Poul; Povlsen, Jørn Hedegaard

    1998-01-01

    We present a model for relative intensity noise (RIN) in DFB fibre lasers which predicts measured characteristics accurately. Calculation results implies that the RIN decreases rapidly with stronger Bragg grating and higher pump power. We propose here a simplified model based on three spatially...... independent rate equations to describe the dynamic response of erbium doped DFB fibre lasers on pump power fluctuations, using coupled-mode theory to calculate the steady-state hole-burning of the erbium ion inversion...

  11. Power consumption in multicore fibre networks

    DEFF Research Database (Denmark)

    Nooruzzaman, Md; Jain, Saurabh; Jung, Yongmin

    2017-01-01

    We study potential energy savings in MCF-based networks compared to SMF-based ones in a Pan-European network topology based on the power consumption of recently fabricated cladding-pumped multi-core optical fibre amplifiers.......We study potential energy savings in MCF-based networks compared to SMF-based ones in a Pan-European network topology based on the power consumption of recently fabricated cladding-pumped multi-core optical fibre amplifiers....

  12. Design of distributed feedback fibre lasers

    DEFF Research Database (Denmark)

    Lauridsen, Vibeke Claudia; Søndergaard, Thomas; Varming, Poul

    1997-01-01

    A numerical model for erbium fibre lasers with Bragg gratings is presented. The model is used to optimize the location of a discrete phase-shift and the phase-shift magnitude for a distributed phase-shift.......A numerical model for erbium fibre lasers with Bragg gratings is presented. The model is used to optimize the location of a discrete phase-shift and the phase-shift magnitude for a distributed phase-shift....

  13. Polarisation control of DFB fibre lasers

    DEFF Research Database (Denmark)

    Varming, Poul; Philipsen, Jacob Lundgreen; Berendt, Martin Ole

    1998-01-01

    The polarisation properties of a distributed feedback (DFB) fibre laser are investigated. It is shown experimentally that the birefringence of the UV induced phase-shift is the dominating effect controlling the polarisation properties of the laser......The polarisation properties of a distributed feedback (DFB) fibre laser are investigated. It is shown experimentally that the birefringence of the UV induced phase-shift is the dominating effect controlling the polarisation properties of the laser...

  14. Design Methods for Fibre Reinforced Concrete

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    The present paper describes the outline of a research project on Fibre Reinforced Concrete (FRC) currently being carried out in Denmark under the supervision of Danish Council of Technology, Danish Technical Research Council and Danish Natural Science Research Counsil.......The present paper describes the outline of a research project on Fibre Reinforced Concrete (FRC) currently being carried out in Denmark under the supervision of Danish Council of Technology, Danish Technical Research Council and Danish Natural Science Research Counsil....

  15. Mode conversion in magneto photonic crystal fibre

    International Nuclear Information System (INIS)

    Otmani, Hamza; Bouchemat, Mohamed; Hocini, Abdesselam; Boumaza, Touraya; Benmerkhi, Ahlem

    2017-01-01

    The first concept of an integrated isolator was based on nonreciprocal TE–TM mode conversion, the nonreciprocal coupling between these modes is caused by the Faraday rotation if the magnetization is aligned along the z–axis, parallel to mode propagation. We propose to study this magneto-optical phenomenon, by the simulation of magneto photonic crystal fibre (MPCF), it consists of a periodic triangular lattice of air-holes filled with magnetic fluid which consists of magnetic nanoparticles into a BIG (Bismuth Iron Garnet) fibre. We simulated the influence of gyrotropy and the wavelength, and calculated Faraday rotation and modal birefringence. In this fibre the light is guided by internal total reflection, like classical fibres. However it was shown that they could function on a mode conversion much stronger than conventional fibres. - Highlights: • We propose to study mode conversion TE–TM, by the simulation of magneto photonic crystal fibre (MPCF). • We simulated the influence of gyrotropy. • We simulated the wavelength. • We calculated Faraday rotation. • We calculated modal birefringence.

  16. A Class I (Senofilcon A) Soft Contact Lens Prevents UVB-Induced Ocular Effects, Including Cataract, in the Rabbit In Vivo

    Science.gov (United States)

    Lin, Li-Ren; Leverenz, Victor R.; Dang, Loan

    2011-01-01

    Purpose. UVB radiation from sunlight is known to be a risk factor for human cataract. The purpose in this study was to investigate the ability of a class I UV-blocking soft contact lens to protect against UVB-induced effects on the ocular tissues of the rabbit in vivo. Methods. Eyes of rabbits were exposed to UVB light for 30 minutes (270–360 nm, peak at 310 nm, 1.7 mW/cm2 on the cornea). Eyes were irradiated in the presence of either a UV-blocking senofilcon A contact lens, a minimally UV-blocking lotrafilcon A contact lens, or no contact lens at all. Effects on the cornea and lens were evaluated at various times after exposure. Results. Eyes irradiated with no contact lens protection showed corneal epithelial cell loss plus lens epithelial cell swelling, vacuole formation, and DNA single-strand breaks, as well as lens anterior subcapsular opacification. The senofilcon A lens protected nearly completely against the UVB-induced effects, whereas the lotrafilcon A lens showed no protection. Conclusions. The results indicate that use of a senofilcon A contact lens is beneficial in protecting ocular tissues of the rabbit against the harmful effects of UVB light, including photokeratitis and cataract. PMID:21421866

  17. UV-B–Induced DNA Damage and Repair in the Mouse Lens

    Science.gov (United States)

    Mesa, Rosana; Bassnett, Steven

    2013-01-01

    Purpose. Epidemiologic studies have linked UV-B exposure to development of cortical cataracts, but the underlying molecular mechanism(s) is unresolved. Here, we used a mouse model to examine the nature and distribution of DNA photolesions produced by ocular UV-B irradiation. Methods. Anesthetized mice, eye globes, or isolated lenses were exposed to UV-B. Antibodies specific for 6-4 photoproducts (6-4 PPs) or cyclobutane pyrimidine dimers (CPDs) were used to visualize DNA adducts. Results. Illumination of intact globes with UV-B–induced 6-4 PP and CPD formation in cells of the cornea, anterior iris, and central lens epithelium. Photolesions were not detected in retina or lens cells situated in the shadow of the iris. Photolesions in lens epithelial cells were produced with radiant exposures significantly below the minimal erythemal dose. Lens epithelial cells rapidly repaired 6-4 PPs, but CPD levels did not markedly diminish, even over extended postirradiation recovery periods in vitro or in vivo. The repair of 6-4 PPs did not depend on the proliferative activity of the epithelial cells, since the repair rate in the mitotically-active germinative zone (GZ) was indistinguishable from that of quiescent cells in the central epithelium. Conclusions. Even relatively modest exposures to UV-B produced 6-4 PP and CPD photolesions in lens epithelial cells. Cyclobutane pyrimidine dimer lesions were particularly prevalent and were repaired slowly if at all. Studies on sun-exposed skin have established a causal connection between photolesions and so-called UV-signature mutations. If similar mechanisms apply in the lens, it suggests that somatic mutations in lens epithelial cells may contribute to the development of cortical cataracts. PMID:24022010

  18. UV-B-induced DNA damage and repair in the mouse lens.

    Science.gov (United States)

    Mesa, Rosana; Bassnett, Steven

    2013-10-17

    Epidemiologic studies have linked UV-B exposure to development of cortical cataracts, but the underlying molecular mechanism(s) is unresolved. Here, we used a mouse model to examine the nature and distribution of DNA photolesions produced by ocular UV-B irradiation. Anesthetized mice, eye globes, or isolated lenses were exposed to UV-B. Antibodies specific for 6-4 photoproducts (6-4 PPs) or cyclobutane pyrimidine dimers (CPDs) were used to visualize DNA adducts. Illumination of intact globes with UV-B-induced 6-4 PP and CPD formation in cells of the cornea, anterior iris, and central lens epithelium. Photolesions were not detected in retina or lens cells situated in the shadow of the iris. Photolesions in lens epithelial cells were produced with radiant exposures significantly below the minimal erythemal dose. Lens epithelial cells rapidly repaired 6-4 PPs, but CPD levels did not markedly diminish, even over extended postirradiation recovery periods in vitro or in vivo. The repair of 6-4 PPs did not depend on the proliferative activity of the epithelial cells, since the repair rate in the mitotically-active germinative zone (GZ) was indistinguishable from that of quiescent cells in the central epithelium. Even relatively modest exposures to UV-B produced 6-4 PP and CPD photolesions in lens epithelial cells. Cyclobutane pyrimidine dimer lesions were particularly prevalent and were repaired slowly if at all. Studies on sun-exposed skin have established a causal connection between photolesions and so-called UV-signature mutations. If similar mechanisms apply in the lens, it suggests that somatic mutations in lens epithelial cells may contribute to the development of cortical cataracts.

  19. Primary intraocular lens implantation for penetrating lens trauma in Africa.

    Science.gov (United States)

    Bowman, R J; Yorston, D; Wood, M; Gilbert, C; Foster, A

    1998-09-01

    This study aimed to audit the surgical strategy of primary posterior chamber intraocular lens implantation for cases of recent penetrating trauma involving the lens in an African population. Retrospective, noncomparative case series. Seventy-two cases are reported, including all patients who underwent primary intraocular lens implantation for traumatic cataract extraction performed within 1 month of injury between 1988 and 1996. Demographic characteristics and follow-up attendance rates are analyzed. Surgical technique and the occurrence of intraoperative and postoperative complications are reported. Visual outcomes are reported with detailed analysis for cases of poor visual outcome. Mean age was 14.3 years (standard deviation = 11.1), 57 (79%) were male and 15 (21%) were female (chi-square = 23.66, P capsule had been breached by the trauma in 27 (38%) cases, and 15 of these required anterior vitrectomy. Capsular fixation of the implant was achieved in 49% of patients, the remainder having sulcus fixation. Intraoperative rupture of the posterior capsule occurred in four cases. The only common postoperative complication was acute fibrinous anterior uveitis, which occurred in 29 (40%) patients, and 32% of patients followed up for at least 6 months required secondary posterior capsulotomy. This was more common in younger patients (chi-square = 4.2, P < 0.05). Corrected postoperative visual acuities were available for 51 patients, of which 71% achieved 20/60 or better visual acuity. Patients 6 years of age or younger were less likely to achieve 20/60 (chi-square = 6.61, P = 0.01). This surgical strategy has proved successful, producing good visual results and causing no sight-threatening complications. Primary posterior capsulotomy may be appropriate for younger patients.

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

    Science.gov (United States)

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

    2013-11-01

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

  1. Research on one manual zoom liquid lens

    Science.gov (United States)

    Zhao, Cunhua; Shi, Yongpeng; Li, Wenjiao; Li, Congcong

    2011-11-01

    In liquid zoom lens, the accurate fixed-focus location needs the accurate calculation of focal length. That is to say, the accurate calculation of surface curvature must be obtained. Therefore, the research of their relation in liquid zoom lens becomes extremely important which has a directly theoretical instruction for the design of liquid zoom lenses. In our paper, the relation is studied. A manual liquid lens is reported which has upper and nether components with specificaton Φ12×5mm. The zoom lens is obtained by the upper component circumvolving down into the nether components.

  2. Numerical analyses of planer plasmonic focusing lens

    Science.gov (United States)

    Chou, Yen-Yu; Lee, Yeeu-Chang

    2018-03-01

    The use of polystyrene (PS) sphere lithography has been widely applied in the fabrication of micron and nano structures, due to their low cost and ease of fabrication in large scale applications. This study evaluated the feasibility of plasmonic lens base on metal thin films with nanohole structures fabricated by using PS sphere lithography through three-dimensional (3D) finite difference time domain (FDTD) method. We calculated the intensity profile of lens with various wavelength of incident light, lens size, cutting positions, diameters of nanohole, and periods of nanohole to investigate the geometric parameters influence on the focusing properties of the plasmonic lens.

  3. The effect of fibre content, fibre size and alkali treatment to Charpy impact resistance of Oil Palm fibre reinforced composite material

    Science.gov (United States)

    Fitri, Muhamad; Mahzan, Shahruddin

    2016-11-01

    In this research, the effect of fibre content, fibre size and alkali treatment to the impact resistance of the composite material have been investigated, The composite material employs oil palm fibre as the reinforcement material whereas the matrix used for the composite materials are polypropylene. The Oil Palm fibres are prepared for two conditions: alkali treated fibres and untreated fibres. The fibre sizes are varied in three sizes: 5mm, 7mm and 10mm. During the composite material preparation, the fibre contents also have been varied into 3 different percentages: 5%, 7% and 10%. The statistical approach is used to optimise the variation of specimen determined by using Taguchi method. The results were analyzed also by the Taguchi method and shows that the Oil Palm fibre content is significantly affect the impact resistance of the polymer matrix composite. However, the fibre size is moderately affecting the impact resistance, whereas the fibre treatment is insignificant to the impact resistance of the oil palm fibre reinforced polymer matrix composite.

  4. Fibre-matrix interface properties in a wood fibre reinforced cement matrix

    NARCIS (Netherlands)

    Sierra Beltran, M.G.; Schlangen, H.E.J.G.

    2010-01-01

    Wood fibres can be a low cost reinforcement for cementitious materials for structural applications. In order to design a ductile cementitious material reinforced with softwood fibres the fibrematrix interface properties are studied. Pullout tests have been carried out to determine the bond strength

  5. Analysis of filler--fibre interaction in fly ash filled short fibre-epoxy ...

    Indian Academy of Sciences (India)

    These properties showed an improvement of about 30-40% as compared to the ones where a single reinforcement either ash or fibre was used. Further, they exhibited uniform distribution of defects whose population was least compared to the situation where only one component (either filler or fibre) as reinforcement was ...

  6. EVALUATION OF FIBRE LENGTH DISTRIBUTION IN A SHORT GLASS FIBRE REINFORCED PA-6

    Directory of Open Access Journals (Sweden)

    Camilla Ravalico

    2015-09-01

    Full Text Available The aim of this work is to evaluate the fibre length distribution in a polyamide reinforced by short glass fibre. The fibre length and the fibre orientation distributions strongly influence the mechanical properties of short fibre reinforced composites. The sample investigated is a 30GFPA6 (polyamide-6 reinforced by 30 % by weight glass fibre, extracted from an injection-moulded plate. The digital reconstruction of the three-dimensional structure of the sample was obtained by synchrotron radiation micro-computed tomography (micro-CT, a high spatial resolution non-destructive technique. One global and one local method have been tested for the automatic evaluation of the fibre length distribution in our sample. The global method is based on the mean fibre length distribution computed from the Star Length Distribution (SLD, a morphological parameter. The local method is based on a 3D skeletonize function. The results are discussed in the light of the experimental data available in literature.

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

    Science.gov (United States)

    Butylina, Svetlana; Martikka, Ossi; Kärki, Timo

    2011-04-01

    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.

  8. Vibrated and self-compacting fibre reinforced concrete: experimental investigation on the fibre orientation

    Science.gov (United States)

    Conforti, A.; Plizzari, G. A.; Zerbino, R.

    2017-09-01

    In addition to the fibre type and content, the residual properties of fibre reinforced concrete are influenced by fibre orientation. Consequently, the performance fibre reinforced concrete can be affected by its fresh properties (workability, flowing capacity) and by casting and compaction processes adopted. This paper focuses on the study of the orientation of steel or macro-synthetic fibres in two materials characterized by very different fresh properties: vibrated and self-compacting concrete. Four rectangular slabs 1800 mm long, 925 mm wide and 100 mm high were produced changing concrete and fibre type. From each slab, eighteen small prisms (550 mm long) were firstly cut either orthogonal or parallel to casting direction and, secondly, notched and tested in bending according to EN 14651. Experimental results showed that the toughness properties of a thin slab significantly varies both in vibrated and self-compacting concrete, even if in case of self-compacting concrete this variation resulted higher. Steel fibres led to greater variability of results compared to polymer one, underlining a different fibre orientation. A discussion on the relative residual capacity measured on the prisms sawn from the slabs and the parameters obtained from standard specimens is performed.

  9. Exchange of tears under a contact lens is driven by distortions of the contact lens.

    Science.gov (United States)

    Maki, Kara L; Ross, David S

    2014-12-01

    We studied the flow of the post-lens tear film under a soft contact lens to understand how the design parameters of contact lenses can affect ocular health. When a soft contact lens is inserted, the blinking eyelid causes the lens to stretch in order to conform to the shape of the eye. The deformed contact lens acts to assume its un-deformed shape and thus generates a suction pressure in the post-lens tear film. In consequence, the post-lens tear fluid moves; it responds to the suction pressure. The suction pressure may draw in fresh fluid from the edge of the lens, or it may eject fluid there, as the lens reassumes its un-deformed shape. In this article, we develop a mathematical model of the flow of the post-lens tear fluid in response to the mechanical suction pressure of a deformed contact lens. We predict the amount of exchange of fluid exchange under a contact lens and we explore the influence of the eye's shape on the rate of exchange of fluid. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  10. Fibre-Bragg-grating writing in single-mode optical fibres by UV femtosecond pulses

    International Nuclear Information System (INIS)

    Zagorul'ko, K A; Kryukov, P G; Dianov, Evgenii M; Dragomir, A; Nikogosyan, D N

    2003-01-01

    Fibre-Bragg-grating writing in single-mode optical fibres by the phase-mask method using 220-fs, 264-nm UV pulses of intensity 31 - 77 GW cm -2 is reported for the first time. The achieved degree of modulation of the photoinduced refractive index was 1.9 x 10 -3 in an H 2 -loaded SMF-28 telecommunication fibre and 1.1 x 10 -3 in a H 2 -free Nufern GF1 fibre. The dependence of the induced refractive index on the intensity for the same irradiation fluences in the case of the H 2 -loaded SMF-28 fibre shows that the refractive index is induced due to nonlinear absorption. (letters)

  11. Polarisation maintaining fibre with pure silica core and two depressed claddings for fibre optic gyroscope

    Science.gov (United States)

    Kurbatov, A. M.; Kurbatov, R. A.; Voloshin, V. V.; Vorob'ev, I. L.; Kolosovsky, A. O.

    2016-12-01

    Polarisation maintaining (PM) fibre is described with pure silica core and two depressed claddings for fibre optic gyro (FOG) sensing coil. Detailed mathematical simulation is presented by supermodes method, which is extremely necessary for such fibre. Simulation is fulfilled by frequency domain finite difference method (FDFDM), taking into account all details of realistic index profile with stress applying parts, while the leakage/bend loss occur in the region with complex index, surrounding the fibre. Cutoff and small bend loss are theoretically predicted and experimentally measured with excellent agreement between theory and experiment. Polarisation maintaining ability is measured in the form of conventional h-parameter (7.1·10-6 1/m) for 90-μm diameter fibre with birefringence value only 3.9·10-4.

  12. Influence of fibre design and curvature on crosstalk in multi-core fibre

    Energy Technology Data Exchange (ETDEWEB)

    Egorova, O N; Astapovich, M S; Semjonov, S L; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Melnikov, L A [Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Saratov Branch, Saratov (Russian Federation); Salganskii, M Yu [G.G.Devyatykh Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation); Mishkin, S N; Nishchev, K N [N.P. Ogarev Mordovia State University, Physics and Chemistry Institute, Saransk (Russian Federation)

    2016-03-31

    We have studied the influence of cross-sectional structure and bends on optical cross-talk in a multicore fibre. A reduced refractive index layer produced between the cores of such fibre with a small centre-to-centre spacing between neighbouring cores (27 μm) reduces optical cross-talk by 20 dB. The cross-talk level achieved, 30 dB per kilometre of the length of the multicore fibre, is acceptable for a number of applications where relatively small lengths of fibre are needed. Moreover, a significant decrease in optical cross-talk has been ensured by reducing the winding diameter of multicore fibres with identical cores. (fiber optics)

  13. Cholesterol Bilayer Domains in the Eye Lens Health: A Review.

    Science.gov (United States)

    Widomska, Justyna; Subczynski, Witold K; Mainali, Laxman; Raguz, Marija

    2017-12-01

    The most unique biochemical characteristic of the eye lens fiber cell plasma membrane is its extremely high cholesterol content, the need for which is still unclear. It is evident, however, that the disturbance of Chol homeostasis may result in damages associated with cataracts. Electron paramagnetic resonance methods allow discrimination of two types of lipid domains in model membranes overloaded with Chol, namely, phospholipid-cholesterol domains and pure Chol bilayer domains. These domains are also detected in human lens lipid membranes prepared from the total lipids extracted from lens cortices and nuclei of donors from different age groups. Independent of the age-related changes in phospholipid composition, the physical properties of phospholipid-Chol domains remain the same for all age groups and are practically identical for cortical and nuclear membranes. The presence of Chol bilayer domains in these membranes provides a buffering capacity for cholesterol concentration in the surrounding phospholipid-Chol domains, keeping it at a constant saturating level and thus keeping the physical properties of the membrane consistent with and independent of changes in phospholipid composition. It seems that the presence of Chol bilayer domains plays an integral role in the regulation of cholesterol-dependent processes in fiber cell plasm membranes and in the maintenance of fiber cell membrane homeostasis.

  14. Intraocular and crystalline lens protection from ultraviolet damage.

    Science.gov (United States)

    Sliney, David H

    2011-07-01

    Although the risks of excess solar ultraviolet (UV) exposure of the skin are well recognized, the need for eye protection is frequently overlooked, or when sunglasses are also recommended, specific guidance is wrong or is not explained. Guidance from the World Health Organization at its InterSun webpage advises people to wear "wrap-around" sunglasses under many conditions. The objective of this study was to examine the need for UV filtration in prescription lenses, contact lenses, and sunglasses. The geometry of UV exposure of both eyes, solar position, ground reflection, pupil size, and lid opening were studied. Because an accurate determination of cumulative ocular exposure is difficult, the cornea itself can serve as a biologic dosimeter, because photokeratitis is not experienced on a daily basis but does under certain ground-surface and sunlight conditions. From a knowledge of the UV-threshold dose required to produce photokeratitis, we have an upper level of routine ocular exposure to ambient UV. From ambient UV measurements and observed photokeratitis, the upper limits of UV exposure of the crystalline lens or an intraocular lens implant are estimated. The risk of excess UV exposure of the germinative cells of the lens is greatest from the side. Sunglasses can actually increase UV exposure of the germinative region of the crystalline lens and the corneal limbus by disabling the eyes' natural protective mechanisms of lid closure and pupil constriction! The level of UV-A risk is difficult to define. Proper UV-absorbing contact lenses offer the best mode for filtering needless exposure of UV radiation of the lens and limbus.

  15. Latest developments in silica fibre luminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D. A.; Abdul S, S. F.; Jafari, S. M.; Alanazi, A. [University of Surrey, Department of Physics, GU2 7XH Guildford, Surrey (United Kingdom); Amouzad M, G. [University of Malaya, Faculty of Engineering, Department of Electrical Engineering, Integrated Lightwave Research Group, 50603 Kuala Lumpur (Malaysia); Addul R, H. A.; Mizanur R, A. K. M.; Zubair, H. T.; Begum, M.; Yusoff, Z.; Omar, N. Y. M. [Multimedia University, Faculty of Engineering, 2010 Cyberjaya, Selangor (Malaysia); Maah, M. J. [University of Malaya, Department of Chemistry, 50603 Kuala Lumpur (Malaysia); Collin, S. [National Physical Laboratory, Hampton Road, Teddington, TW11 OLW Middlesex (United Kingdom); Mat-Sharif, K. A.; Muhd-Yassin, S. Z.; Zulkifli, M. I., E-mail: d.a.bradley@surrey.ac.uk [Telekom Malaysia Research and Development Sdn Bhd., 63000 Cyberjaya, Selangor (Malaysia)

    2015-10-15

    Full text: Using tailor made sub-mm diameter doped-silica fibres, we are carrying out luminescence dosimetry studies for a range of situations, including thermoluminescence (Tl)investigations on a liquid alpha source formed of {sup 223}RaCl (the basis of the Bayer Health care product Xofigo), the Tl response to a 62 MeV proton source and Tl response to irradiation from an {sup 241}Am-Be neutron source. In regard to the former, in accord with the intrinsic high linear energy transfer (Let) and short path length (<100 um) of the α-particles in calcified tissue, the product is in part intended as a bone-seeking radionuclide for treatment of metastatic cancer, offering high specificity and efficacy. The Tl yield of Ge-doped SiO{sub 2} fibres has been investigated including for photonic crystal fibre un collapsed, flat fibres and single mode fibres, these systems offering many advantages over conventional passive dosimetry types. In particular, one can mention comparable and even superior sensitivity, an effective atomic number Z{sub eff} of the silica dosimetric material close to that of bone, and the glassy nature of the fibres offering the additional advantage of being able to place such dosimeters directly into liquid environments. Finally we review the use of our tailor made fibres for on-line radioluminescence measurements of radiotherapy beams. The outcome from these various lines of research is expected to inform development of doped fiber radiation dosimeters of versatile utility, ranging from clinical applications through to industrial studies and environmental evaluations. (Author)

  16. Experimental and numerical study on refractive index sensors based on fibre Bragg gratings inscribed in multimode fibre

    Science.gov (United States)

    Filipe Kuhne, Jean; Rocha, Ana Maria; de Oliveira, Valmir; José Kalinowski, Hypolito; Canute Kamikawachi, Ricardo

    2018-02-01

    In this work is reported the experimental and numerical results of the refractive index response of etched fibre Bragg gratings written in a graded index multimode fibre. The responses of the modes coupled by the grating inscribed in a multimode fibre are compared with the mode coupled by a grating inscribed in single mode fibre. The results of this study show that the refractive index sensitivity and the dynamical range of etched fibre Bragg gratings written in multimode fibres are higher than the ones verified in single-mode fibres. The determination of oil-biodiesel blend concentrations are also compared as an example of practical applications. It is shown that a greater core diameter of the multimode fibre enables the Bragg gratings to exhibit enhanced sensitivity without requiring further fibre diameter reduction.

  17. Microanalytical investigation of fibre-reinforced ceramic materials

    International Nuclear Information System (INIS)

    Meier, B.; Grathwohl, G.

    1989-01-01

    Microanalytical investigations have been made on samples of ceramic fibres (SiC fibres, (Nicalon) C fibre coated with TiN) and fibre-reinforced ceramics (SiC-and glass-matrices). High resolution Auger electron spectroscopy (HRAES), electron probe microanalysis (EPMA) and scanning electron microscopy were employed for these examinations. Analysis was best performed with HRAES on account of its lateral and depth resolution. Some of the problems involved in this technique are discussed e.g. electron beam effects. AES depth profiles of ceramic fibres are reported and compared with the surface analysis of fibres in the composites after being broken in situ. (orig.)

  18. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life.

    Directory of Open Access Journals (Sweden)

    Niels Lynnerup

    Full Text Available BACKGROUND: Lens crystallines are special proteins in the eye lens. Because the epithelial basement membrane (lens capsule completely encloses the lens, desquamation of aging cells is impossible, and due to the complete absence of blood vessels or transport of metabolites in this area, there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its (14C content from the atmospheric carbon dioxide. The (14C content of the lens proteins thus reflects the atmospheric content of (14C when the lens crystallines were formed. Precise radiocarbon dating is made possible by comparing the (14C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric (14C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close relationship may be further expressed as a mathematical model, which takes into account the timing of the crystalline formation. CONCLUSIONS/SIGNIFICANCE: Such a life-long permanence of human tissue has hitherto only been described for dental enamel. In confront to dental enamel it must be held in mind that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14C content of various tissues may be used to assess turnover rates and degree of substitution (for example for brain cell DNA. Potential targets may be nervous tissues in terms of senile or pre

  19. Influence of the Testing Gage Length on the Strength, Young's Modulus and Weibull Modulus of Carbon Fibres and Glass Fibres

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Pardini

    2002-10-01

    Full Text Available Carbon fibres and glass fibres are reinforcements for advanced composites and the fiber strength is the most influential factor on the strength of the composites. They are essentially brittle and fail with very little reduction in cross section. Composites made with these fibres are characterized by a high strength/density ratio and their properties are intrisically related to their microstructure, i.e., amount and orientation of the fibres, surface treatment, among other factors. Processing parameters have an important role in the fibre mechanical behaviour (strength and modulus. Cracks, voids and impurities in the case of glass fibres and fibrillar misalignments in the case of carbon fibres are created during processing. Such inhomogeneities give rise to an appreciable scatter in properties. The most used statistical tool that deals with this characteristic variability in properties is the Weibull distribution. The present work investigates the influence of the testing gage length on the strength, Young's modulus and Weibull modulus of carbon fibres and glass fibres. The Young's modulus is calculated by two methods: (i ASTM D 3379M, and (ii interaction between testing equipment/specimen The first method resulted in a Young modulus of 183 GPa for carbon fibre, and 76 GPa for glass fibre. The second method gave a Young modulus of 250 GPa for carbon fibre and 50 GPa for glass fibre. These differences revelead differences on how the interaction specimen/testing machine can interfere in the Young modulus calculations. Weibull modulus can be a tool to evaluate the fibre's homogeneity in terms of properties and it is a good quality control parameter during processing. In the range of specimen gage length tested the Weibull modulus for carbon fibre is ~ 3.30 and for glass fibres is ~ 5.65, which indicates that for the batch of fibres tested, the glass fibre is more uniform in properties.

  20. [Acanthamoeba isolation from contact lens solution of contact lens wearers without keratitis].

    Science.gov (United States)

    Watanabe, R; Ishibashi, Y; Hommura, S; Ishii, K

    1994-05-01

    Acanthamoeba keratitis seems to be associated with wearing contact lenses. As controls, we surveyed contact lens wearers without keratitis. Contact lens solutions of 93 persons were examined in order to identify risk factors for contamination by Acanthamoeba. Therefore, the contact lens disinfection system and storage schedules were studied in each case. Acanthamoeba organisms were isolated from 4 specimens (4.3%). The incidence of Acanthamoeba was higher in specimens of soft contact lens solution than in those of hard contact lens solution, and all the Acanthamoeba positive cases had been using tap water.