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Sample records for active plzt lens

  1. Dielectric and piezoelectric studies of perovskite-tungsten bronze structured (1 - x)PLZT-xPBBiN nanoceramic composites by high-energy mechanical activation technique

    International Nuclear Information System (INIS)

    Ramam, Koduri; Lopez, Marta; Chandramouli, K.

    2009-01-01

    Polycrystalline (1 - x)PLZT-xPBBiN ferroelectric complex ceramic nanocomposites were synthesized through high-energy mechanical activation technique. It is found that milling time has a significant impact on the phase formation, particle size and grain growth. The optimized compositions were subjected to XRD, SEM, dielectric and piezoelectric studies. Powder X-ray diffraction studies revealed that the nanocomposites consisted of both perovskite (tetragonal) and tungsten bronze (orthorhombic) structures whilst pure PLZT showed perovskite structure and pure PBBN showed tungsten bronze structure. As the PBBN content increased, the in situ prepared perovskite and tungsten bronze nanocomposites revealed a bi-phase formation. It is worth mentioning that crack-free nanoceramic composites were obtained. The maximum dielectric constant (ε RT = 2509), piezoelectric planar coupling coefficient (k p = 0.584) and the piezoelectric charge coefficient (d 33 = 596 pC/N) were observed for x = 0.6 nanoceramic composite. It has been observed that the dielectric and piezoelectric constants increased gradually with increasing x up to 0.6 and was found optimum, which could be ideal for electromechanical and energy harvesting applications.

  2. PLZT capacitor on glass substrate

    Science.gov (United States)

    Fairchild, M. Ray; Taylor, Ralph S.; Berlin, Carl W.; Wong, Celine W. K.; Ma, Beihai; Balachandran, Uthamalingam

    2016-01-05

    A lead-lanthanum-zirconium-titanate (PLZT) capacitor on a substrate formed of glass. The first metallization layer is deposited on a top side of the substrate to form a first electrode. The dielectric layer of PLZT is deposited over the first metallization layer. The second metallization layer deposited over the dielectric layer to form a second electrode. The glass substrate is advantageous as glass is compatible with an annealing process used to form the capacitor.

  3. PLZT thermal/flash protective goggles: device concepts and constraints

    International Nuclear Information System (INIS)

    Cutchen, J.T.

    1979-01-01

    In 1975 Sandia Laboratories began the design and development of PLZT Goggles for the US Air Force to provide protection from temporary flashblindness and permanent retinal burns caused by the brilliant flash of nuclear explosions. The user requirements, system and physical constraints, and use/storage environments were all considered in arriving at the final design goals. When the program began, there was no industrial capability to manufacture large-aperture PLZT materials or bonded lens assemblies. The technology has been established from a laboratory baseline in a brief period, and operational testing and evaluation by the Air Force has been completed. The goggles, identified as the EEU-2/P,, are now in production

  4. Excimer Laser Deposition of PLZT Thin Films

    National Research Council Canada - National Science Library

    Petersen, GAry

    1991-01-01

    .... In order to integrate these devices into optical systems, the production of high quality thin films with high transparency and perovskite crystal structure is desired. This requires development of deposition technologies to overcome the challenges of depositing and processing PLZT thin films.

  5. Coprecipitation-assisted hydrothermal synthesis of PLZT hollow nanospheres

    International Nuclear Information System (INIS)

    Zhu, Renqiang; Zhu, Kongjun; Qiu, Jinhao; Bai, Lin; Ji, Hongli

    2010-01-01

    Lanthanum-modified lead zirconate titanate Pb 1-x La x (Zr 1-y Ti y )O 3 (PLZT) hollow nanospheres have been successfully prepared via a template-free hydrothermal method using the well-mixed coprecipitated precursors and the KOH mineralizer. The structure, composition, and morphology of the PLZT hollow nanospheres were characterized by XRD (X-ray diffraction), ICP (inductive coupled plasma emission spectrometer), FTIR (Fourier transform infrared spectra), TG/DTA (thermogravimetric analysis and differential thermal analysis), TEM (transmission electron microscopy) and SEAD (selected area diffraction). The results show that the composition and the morphology control of the PLZT products are determined by the KOH concentration. The PLZT hollow nanospheres with uniform size of about 4 nm were synthesized in the presence of 5 M KOH. The crystalline nanoparticles can be prepared at dilute KOH, in contrast to the amorphous powders prepared at concentrated KOH. Formation mechanisms of the PLZT hollow nanospheres are also discussed.

  6. PLZT capacitor and method to increase the dielectric constant

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Ralph S.; Fairchild, Manuel Ray; Balachjandran, Uthamalingam; Lee, Tae H.

    2017-12-12

    A ceramic-capacitor includes a first electrically-conductive-layer, a second electrically-conductive-layer arranged proximate to the first electrically-conductive-layer, and a dielectric-layer interposed between the first electrically-conductive-layer and the second electrically-conductive-layer. The dielectric-layer is formed of a lead-lanthanum-zirconium-titanate material (PLZT), wherein the PLZT is characterized by a dielectric-constant greater than 125, when measured at 25 degrees Celsius and zero Volts bias, and an excitation frequency of ten-thousand Hertz (10 kHz). A method for increasing a dielectric constant of the lead-lanthanum-zirconium-titanate material (PLZT) includes the steps of depositing PLZT to form a dielectric-layer of a ceramic-capacitor, and heating the ceramic-capacitor to a temperature not greater than 300.degree. C.

  7. Micro-mirror with hybrid photoelectric-electrostatic driving of PLZT ceramic

    Science.gov (United States)

    Tang, Y. J.; Chen, Y. S.; Qiao, K.; Wang, X. J.

    2018-02-01

    A novel micro-mirror driven by hybrid photoelectric-electrostatic actuation of PLZT ceramic is proposed based on the anomalous photovoltaic effect of PLZT ceramic. On the basis of analysis of coupling relationships of multi-physics fields of PLZT ceramic, the photovoltage of PLZT ceramic is established during illumination and light off phases. Furthermore, the relationship between the driving displacement and the photovoltage of PLZT ceramics is present. In addition, the feasibility of micro-mirror with hybrid photoelectric-electrostatic driving is verified via closed-loop control for photovoltage of PLZT ceramic. The experimental results show that the photovoltage of PLZT ceramics has good dynamic control precision using on-off closed-loop control method.

  8. Distributed Leadership through the Lens of Activity Theory

    Science.gov (United States)

    Yuen, Jeanne Ho Pau; Victor Chen, Der-Thanq; Ng, David

    2016-01-01

    Purpose: Using Activity Theory as an interpretive lens to examine the distribution of leadership, this paper shares a case study on how leadership for an ICT project was distributed in a Singapore school. Method: The case study involved observations of 49 meetings and 34 interviews of leaders and the teachers who were involved in the ICT project.…

  9. 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.

  10. PLZT Ceramic Driving Rotary Micro-mirror Based on Photoelectric-electrostatic Mechanism

    Science.gov (United States)

    Tang, Yujuan; Yang, Zhong; Chen, Yusong; Wang, Xinjie

    2017-12-01

    Based on the anomalous photovoltaic effect of PLZT, a rotary micro-mirror driven by hybrid photoelectric-electrostatic actuation of PLZT ceramic is proposed. Firstly, the mathematical modelling of coupled multi-physics fields of PLZT ceramic is established during illumination and light off phases. Then, the relationship between the rotation angle and the photovoltage of PLZT ceramics is established. In addition, the feasibility of rotary micro-mirror with hybrid photoelectric-electrostatic driving is verified via closed-loop control for photo-induced voltage of PLZT ceramic. The experimental results show that the photo-induced voltage of PLZT ceramics has good dynamic control precision using on-off closed-loop control method.

  11. The effect of physiologic aqueous solutions on the perovskite material lead-lanthanum-zirconium titanate (PLZT)

    Science.gov (United States)

    Foster, William J.; Meen, James K.; Fox, Donald A.

    2016-01-01

    Context Perovskite compounds, including Lead-Lanthanum-Zirconium Titanate (PLZT), have wide technological application because of their unique physical properties. The use of PLZT in neuro-prosthetic systems, such as retinal implants, have been discussed in a number of publications. Since inorganic lead is a retinotoxic compound that produces retinal degeneration, the long-term stability of PLZT in aqueous biological solutions must be determined. Objective We evaluated the stability and effects of prolonged immersion of a PLZT-coated crystal in a buffered balanced salt solution. Materials and Methods Scanning Electron Microscopy and Electron Dispersive Spectroscopy (EDS) using a JEOL JSM 5410 microscope equipped with EDS were utilized to evaluate the samples before and after prolonged immersion. Results We found that lead and other constituents of PLZT leached into the surrounding aqueous medium. Discussion By comparing the unit cell of PLZT with that of CaTiO3, which has been found to react with aqueous fluids, Lead is in the same site in PLZT as Ca is in CaTiO3. It is thus reasonable that PLZT will react with aqueous solutions. Conclusion The results suggest that PLZT must either be coated with a protective layer or is not appropriate for long-term in vivo or in vitro biological applications. PMID:22697294

  12. PLZT light transmittance memory driven with an asymmetric voltage pulse

    International Nuclear Information System (INIS)

    Inoue, Kazuhiko; Morita, Takeshi

    2010-01-01

    PLZT is a ferroelectric electro-optic material, which has been operated with a constant voltage supply to keep a certain optical property. In this study, we propose an optical transmittance memory effect by controlling the domain conditions. The keypoint is to use an asymmetric voltage pulse. In the positive direction, a sufficiently-large voltage is applied to align the polarization directions. After this operation, a relatively small light transmittance is memorized even after removing the electric field. On the other hand, in the negative direction, the amplitude of the voltage is adjusted to the coercive electric field. In this condition, the domain structure is almost the same as the depolarization state. With this voltage supply, the maximum light transmittance can be kept after removing the electric field. Using these voltage operations, the PLZT can obtain two light transmittance states depending on the domain structure. This memory effect should be useful for innovative optical scanners or shutters in the future.

  13. Lens ion transport: from basic concepts to regulation of Na,K-ATPase activity

    Science.gov (United States)

    Delamere, Nicholas A.; Tamiya, Shigeo

    2009-01-01

    In the late 1960s, studies by George Duncan explained many of the basic principles that underlie lens ion homeostasis. The experiments pointed to a permeability barrier close to the surface of the lens and illustrated the requirement for continuous Na,K-ATPase-mediated active sodium extrusion. Without active sodium extrusion, lens sodium and calcium content increases resulting in lens swelling and deterioration of transparency. Later, Duncan's laboratory discovered functional muscarinic and purinergic receptors at the surface of the lens. Recent studies using intact lens suggest purinergic receptors might be involved in short-term regulation of Na,K-ATPase in the epithelium. Purinergic receptor agonists ATP and UTP selectively activate certain Src family tyrosine kinases and stimulate Na,K-ATPase activity. This might represent part of a control mechanism capable of adjusting, perhaps fine tuning, lens ion transport machinery. PMID:18614168

  14. A new approach to integrate PLZT thin films with micro-cantilevers

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana; Volume 34; Issue 4. A new approach to integrate PLZT thin films with micro-cantilevers ... Different types of cantilever beams incorporating PLZT films have been successfully fabricated using 'lift-off' process and bulk micromachining technology. The proposed process can be advantageously ...

  15. Miraflow, Soft Contact Lens Cleaner: Activity Against Acanthamoeba Spp.

    Science.gov (United States)

    Kobayashi, Takeshi; Higuchi-Watanabe, Narumi; Shiraishi, Atsushi; Uno, Toshihiko; Ohashi, Yuichi

    2015-07-01

    Miraflow is a cleaner for soft contact lens which contains 20% isopropyl alcohol. The purpose of this study was to determine the activity against Acanthamoeba trophozoites and cysts for Miraflow. In addition, to determine the activity of combined Miraflow and multipurpose solutions (MPSs) against Acanthamoeba cysts. Two simulated-use studies were conducted. The significance in the log reduction in the number of trophozoites and cysts of A. castellanii strains ATCC 50514 and ATCC 50370 or A. polyphaga ATCC 30461 after exposure to Miraflow alone was determined by the Spearman-Karber method. To examine the activity against Acanthamoeba of combined Miraflow and an MPS, the log reduction in the number of cysts after a 1-min exposure to Miraflow followed by a 4-hr exposure to MPS (ReNu fresh) was also determined. Short-time exposure of 30 sec to Miraflow demonstrated activity against the Acanthamoeba trophozoites. However, a 1-min treatment was only relatively effective (1.1 log reduction) against the cysts of A. castellanii ATCC 50514, but no statistically significant reduction was observed for the cysts of the other 2 strains. The combined use with Miraflow and MPS demonstrated activity against the cysts, and a 3.0, 1.0, or 1.5 log reduction in the numbers was obtained for A. castellanii ATCC 50514, A. castellanii ATCC 50370, and A. polyphaga ATCC 30461, respectively. Exposure to combined Miraflow and MPS resulted in reductions in the number of Acanthamoeba cysts.

  16. PZT/PLZT - elastomer composites with improved piezoelectric voltage coefficient

    Science.gov (United States)

    Harikrishnan, K.; Bavbande, D. V.; Mohan, Dhirendra; Manoharan, B.; Prasad, M. R. S.; Kalyanakrishnan, G.

    2018-02-01

    Lead Zirconate Titanate (PZT) and Lanthanum-modified Lead Zirconate Titanate (PLZT) ceramic sensor materials are widely used because of their excellent piezoelectric coefficients. These materials are brittle, high density and have low achievable piezoelectric voltage coefficients. The density of the sintered ceramics shall be reduced by burnable polymeric sponge method. The achievable porosity level in this case is nearly 60 - 90%. However, the porous ceramic structure with 3-3 connectivity produced by this method is very fragile in nature. The strength of the porous structure is improved with Sylgard®-184 (silicone elastomer) by vacuum impregnation method maintaining the dynamic vacuum level in the range of -650 mm Hg. The elastomer Sylgard®-184 is having low density, low dielectric constant and high compliance (as a resultant stiffness of the composites is increased). To obtain a net dipole moment, the impregnated ceramic composites were subjected to poling treatment with varying conditions of D.C. field and temperature. The properties of the poled PZT/PLZT - elastomer composites were characterized with LCR meter for measuring the dielectric constant values (k), d33 meter used for measuring piezo-electric charge coefficient values (d33) and piezo-electric voltage coefficient (g33) values which were derived from d33 values. The voltage coefficient (g33) values of these composites are increased by 10 fold as compared to the conventional solid ceramics demonstrates that it is possible to fabricate a conformable detector.

  17. Microstructure and Properties of the Ferroelectric-Ferromagnetic PLZT-Ferrite Composites

    Directory of Open Access Journals (Sweden)

    Dariusz Bochenek

    2018-03-01

    Full Text Available The paper presents the technology of ferroelectric-ferromagnetic ceramic composites obtained from PLZT powder (the chemical formula Pb0.98La0.02(Zr0.90Ti0.100.995O3 and ferrite powder (Ni0.64Zn0.36Fe2O4, as well as the results of X-ray powder-diffraction data (XRD measurement, microstructure, dielectric, ferroelectric, and magnetic properties of the composite samples. The ferroelectric-ferromagnetic composite (P-F was obtained by mixing and the synthesis of 90% of PLZT and 10% of ferrite powders. The XRD test of the P-F composite shows a two-phase structure derived from the PLZT component (strong peaks and the ferrite component (weak peaks. The symmetry of PLZT was identified as a rhombohedral ferroelectric phase, while the ferrite was identified as a spinel structure. Scanning electron microscope (SEM microstructure analysis of the P-F ceramic composites showed that fine grains of the PLZT component surrounded large ferrite grains. At room temperature P-F composites exhibit both ferroelectric and ferromagnetic properties. The P-F composite samples have lower values of the maximum dielectric permittivity at the Curie temperature and a higher dielectric loss compared to the PLZT ceramics, however, the exhibit overall good multiferroic properties.

  18. Active compensation of wavefront aberrations by controllable heating of lens with electric film heater matrix.

    Science.gov (United States)

    Chen, Hua; Hou, Lv; Zhou, Xinglin

    2016-08-20

    We present a new apparatus for active compensation of wavefront aberrations by controllable heating of a lens using a film heater matrix. The annular electric film heater matrix, comprising 24 individual heaters, is attached to the periphery of a lens. Utilizing the linear superposition, and wavefront change proportional to the heating energy properties induced by heating, a controllable wavefront can be defined by solving a linear function. The two properties of wavefront change of a lens have been confirmed through a specially designed experiment. The feasibility of the compensation method is validated by compensating the wavefront of a plate lens. The results show that the wavefront of the lens changes from 12.52 to 2.95 nm rms after compensation. With a more precise electric controlling board, better results could be achieved.

  19. Chemical preparation of PLZT powders from nitrate solutions

    International Nuclear Information System (INIS)

    Yoshikawa, Yoshio

    1992-01-01

    PLZT powders were prepared from an aqueous nitrate solution by three methods. They were fine, chemically homogeneous and amorphous. The particle morphologies, however, were very different due to the different physico-chemical coprecipitation conditions. Traditional method provided fine hydroxide coprecipitates, but they agglomerated strongly during drying. When a small amount of hydrogen peroxide was added prior to hydrolysis it converted the hydroxide coprecipitates into hydrate oxides and/or hydrate peroxides and seems to reduce bridge and non-ridging hydroxo groups in coprecipitates. The effect of shape size and the state of agglomeration are qualitatively explained by the chemistry that the more the linkage of bridge hydroxo group develops in the precipitate, the rigider precipitate becomes and that interparticle surface condensation involving non-bridging hydroxo groups is associated with the aggregation of particles during drying. Particle morphologies and related physical characteristics -'drop' density, 'tap' density, and adsorption-desorption isotherm were quite different between method(2) and (3). The process of precipitation (nucleation, growth and agglomeration in the solution) markedly affected the state of the agglomeration of coprecipitates. Method(3) involving the additive and liquid-gas interface reaction provided the most weakly agglomerated powder. The behavior of crystallization and the development of microstructure during calcination were examined as characterization criteria obtaining sinterable powder. 14 refs., 1 tab., 8 figs

  20. Activated Ras alters lens and corneal development through induction of distinct downstream targets

    Directory of Open Access Journals (Sweden)

    Reneker Lixing

    2010-01-01

    Full Text Available Abstract Background Mammalian Ras genes regulate diverse cellular processes including proliferation and differentiation and are frequently mutated in human cancers. Tumor development in response to Ras activation varies between different tissues and the molecular basis for these variations are poorly understood. The murine lens and cornea have a common embryonic origin and arise from adjacent regions of the surface ectoderm. Activation of the fibroblast growth factor (FGF signaling pathway induces the corneal epithelial cells to proliferate and the lens epithelial cells to exit the cell cycle. The molecular mechanisms that regulate the differential responses of these two related tissues have not been defined. We have generated transgenic mice that express a constitutively active version of human H-Ras in their lenses and corneas. Results Ras transgenic lenses and corneal epithelial cells showed increased proliferation with concomitant increases in cyclin D1 and D2 expression. This initial increase in proliferation is sustained in the cornea but not in the lens epithelial cells. Coincidentally, cdk inhibitors p27Kip1 and p57Kip2 were upregulated in the Ras transgenic lenses but not in the corneas. Phospho-Erk1 and Erk2 levels were elevated in the lens but not in the cornea and Spry 1 and Spry 2, negative regulators of Ras-Raf-Erk signaling, were upregulated more in the corneal than in the lens epithelial cells. Both lens and corneal differentiation programs were sensitive to Ras activation. Ras transgenic embryos showed a distinctive alteration in the architecture of the lens pit. Ras activation, though sufficient for upregulation of Prox1, a transcription factor critical for cell cycle exit and initiation of fiber differentiation, is not sufficient for induction of terminal fiber differentiation. Expression of Keratin 12, a marker of corneal epithelial differentiation, was reduced in the Ras transgenic corneas. Conclusions Collectively, these

  1. Physical model of evolution of oxygen subsystem of PLZT-ceramics at neutron irradiation and annealing

    CERN Document Server

    Kulikov, D V; Trushin, Y V; Veber, K V; Khumer, K; Bitner, R; Shternberg, A R

    2001-01-01

    The physical model of evolution of the oxygen subsystem defects of the ferroelectric PLZT-ceramics by the neutron irradiation and isochrone annealing is proposed. The model accounts for the effect the lanthanum content on the material properties. The changes in the oxygen vacancies concentration, calculated by the proposed model, agree well with the polarization experimental behavior by the irradiated material annealing

  2. Large enhancement of the electrocaloric effect in PLZT ceramics prepared by hot-pressing

    Directory of Open Access Journals (Sweden)

    Guangzu Zhang

    2016-06-01

    Full Text Available In this contribution, we demonstrate the optimization of the microstructures of the Pb0.85La0.1(Zr0.65Ti0.35O3 (PLZT relaxor ferroelectric ceramics and subsequent enhancements in their polarization and electrical resistivity by using a hot-pressing process. The resulting superior breakdown strength of hot-pressed PLZT enables the application of high electric field to induce a giant electrocaloric effect, in which the adiabatic change of temperature (ΔT and the isothermal change of entropy (ΔS are around 2 times greater than those of the samples prepared by the conventional sintering approach using muffle furnace. Moreover, the addition of extra PbO to make up the loss of Pb in the high-temperature sintering leads to the further improvements in the phase composition and electrical properties of PLZT, due to inhibition of the pyrochlore phase formation. The relationship among the sintering conditions, the content of excess PbO, and the microstructure as well as the electrical characteristics of PLZT have been investigated in a systematic manner. This work provides a facile approach to enhanced electrocaloric effect in bulk ceramics.

  3. Rhombohedral PLZT piezoelectric microfibers: a combined Raman and X ray diffraction study

    Czech Academy of Sciences Publication Activity Database

    Kozielski, L.; Buixaderas, Elena; Clemens, F.

    2014-01-01

    Roč. 87, 10-11 (2014), s. 982-991 ISSN 0141-1594 R&D Projects: GA ČR GA13-15110S Institutional support: RVO:68378271 Keywords : Raman scattering * X-ray difraccion * piezoelectrics * microfibers * PLZT * extrusion method Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.954, year: 2014

  4. A new approach to integrate PLZT thin films with micro-cantilevers

    Indian Academy of Sciences (India)

    The basic requirement of lift-off process is that the deposition temperature should not exceed 200°C otherwise photoresist will burn out. Therefore, one of the aims of the present work was to prepare PLZT film at lower deposition temperatures, which can be subsequently annealed to form pure perovskite phase. This also ...

  5. PLZT (9/65/35) sintering and characterization through the Pechini and partial oxalate processes

    International Nuclear Information System (INIS)

    Cerqueira, Marinalva; Nasar, Ricardo Silveira; Leite, Edson Roberto; Longo, Elson; Varela, Jode Arana

    1996-01-01

    Zr Ti O 4 obtained by the Pechini method was used as precursor for obtaining PLZT. An aqueous solution of oxalic acid was prepared with ZT, Pb (NO 3 ) 2 and La 2 O 3 particles. After the Pb C 2 O 4 and La 2 O 3 precipitation on ZT, the material was calcined and x-ray diffraction (XRD) showed the cubic phase of PLZT. This material was sintered in two steps and density about 8.0 g/cm 3 were obtained. After second sintering XRD showed the occurrence of tetragonal and rhombohedral phases. This was caused by an estequiometric deviation, however the material showed a high optical transparency. (author)

  6. Rhombohedral PLZT piezoelectric microfibers: a combined Raman and X-ray diffraction study

    Science.gov (United States)

    Kozielski, Lucjan; Buixaderas, Elena; Clemens, Frank

    2014-11-01

    A combination of micro- and macro-scale structural characterization methods was implemented for clarification of the influence of different sintering atmospheres on the structural properties of Pb1-xLax(ZryTi1-y)O3 (PLZT) fibers. Three powders, PbZrO3 and ZrO2 (PZ + Z), PbZrO3 (PZ), and PbZrO3 + PbO (PZ + P), were used for the generation of protective atmospheres. Vibrations corresponding to the rhombohedral phase in (Pb0.93La0.07)(Zr0.65Ti0.35)O3 fibers were measured and mapped along the section of the fibers by micro-Raman spectroscopy. Comparison of the Raman data with the evolution of the unit cell parameters indicates that the PZ + Z protective atmosphere ensures the best properties during the PLZT sintering at the temperature of 1250 °C for 6 hours.

  7. Method of bistable optical information storage using antiferroelectric phase PLZT ceramics

    Science.gov (United States)

    Land, Cecil E.

    1990-01-01

    A method for bistable storage of binary optical information includes an antiferroelectric (AFE) lead lanthanum zirconate titanate (PLZT) layer having a stable antiferroelectric first phase and a ferroelectric (FE) second phase obtained by applying a switching electric field across the surface of the device. Optical information is stored by illuminating selected portions of the layer to photoactivate an FE to AFE transition in those portions. Erasure of the stored information is obtained by reapplying the switching field.

  8. Antenna and coil design for wireless signal detection and charging of embedded power active contact lens.

    Science.gov (United States)

    Ng, Benny; Heckler, Paul; Do, Alex; Azar, Phillip; Leon, Errol; Smilkstein, Tina

    2014-01-01

    This paper presents a screen printed 2.4 GHz antenna and induction charging coil for an active contact lens with a single large pixel user display and on-board 3.8 V 5 uAh rechargeable battery. The antenna traces are printed using silver conductive paste on a 25 um polyethylene terephthalate (PET) substrate. The incoming signal from the antenna feeds into an IC that amplifies and rectifies the signal. The coil provides wireless energy transfer to inductively charge a thin film battery [1] located on the contact lens. The printed antenna achieved a S11 of -4 dB at 2.4 GHz and a gain of -13 dB.

  9. DEVICE FOR MEASURING OF THERMAL LENS PARAMETERS IN LASER ACTIVE ELEMENTS WITH A PROBE BEAM METHOD

    Directory of Open Access Journals (Sweden)

    A. N. Zakharova

    2015-01-01

    Full Text Available We have developed a device for measuring of parameters of thermal lens (TL in laser active elements under longitudinal diode pumping. The measurements are based on the probe beam method. This device allows one to determine sign and optical power of the lens in the principal meridional planes, its sensitivity factor with respect to the absorbed pump power and astigmatism degree, fractional heat loading which make it possible to estimate integral impact of the photoelastic effect to the formation of TL in the laser element. The measurements are performed in a linearly polarized light at the wavelength of 532 nm. Pumping of the laser element is performed at 960 nm that makes it possible to study laser materials doped with Yb3+ and (Er3+, Yb3+ ions. The precision of measurements: for sensitivity factor of TL – 0,1 m-1/W, for astigmatism degree – 0,2 m-1/W, for fractional heat loading – 5 %, for the impact of the photoelastic effect – 0,5 × 10-6 K-1. This device is used for characterization of thermal lens in the laser active element from an yttrium vanadate crystal, Er3+,Yb3+:YVO .

  10. A new lens for supporting and studying science teacher reflections: situating the self in the [activity] system

    Science.gov (United States)

    Criswell, Brett; Calandra, Brendan; Puvirajah, Anton; Brantley-Dias, Laurie

    2015-12-01

    This paper presents a new lens for analyzing written reflections on the teaching experiences of pre-service [science] teachers. The lens, which borrows heavily from Activity Theory, allows science education researchers and teacher educators to identify tensions, disturbances, conflicts, and contradictions within teachers' written reflections as a means to help the participants situate their successes and challenges within the activity systems in which they operate. This paper describes the process through which the lens was crafted, defines the key constructs comprising the lens, applies the lens to the analysis of two purposefully selected reflection documents, and then considers the affordances of the lens. It also discusses how the insights gained from this lens have lead to new ways of facilitating reflection in pre-service science teachers, including the use of Kenneth Snelson's tensegrity sculptures as a metaphor for the goal of reflection. Finally, it connects the tensions identified in the individual reflections of two pre-service science teachers to broader issues being addressed in science education.

  11. Eye lens dose monitoring in the UK nuclear industry using active personal dosemeters.

    Science.gov (United States)

    McWhan, Andrew Forrest; Dobrzynska, Wioletta

    2017-11-20

    The reduction of the dose limit for eye lens from 150 to 20 mSv year-1 must be implemented by EU member states by February 2018. Consequently, there is a requirement for all employers engaged with work with ionising radiation to have appropriate monitoring arrangements in place by this date to demonstrate that they can meet this new limit for all workers. Eye lens dose is conventionally monitored by specific dosemeters worn near the eye. However, it is usually impractical for these dosemeters to be worn at all times in the workplace which can lead to problems accounting for any periods of work when an eye lens dosemeter has not been worn. The Berkeley Approved Dosimetry Service provides a monitoring service for 22 nuclear sites in the UK using active personal dosemeters (APDs) for measuring Hp(10) and Hp(0.07). TLDs for extremity and eye are also issued as appropriate for the working conditions. An analysis of the data from 2007 to 2016 concludes that the values for Hp(0.07) as monitored indirectly by APDs worn on the trunk are comparable to the values assessed by specific Hp(3) eye TLDs. This paper sets out evidence that compliance with the 20 mSv dose limit for the eye lens can be demonstrated using routine issue APDs although specific eye TLDs may still be required to meet international guidance for non-uniform workplace fields. This evidence supports the recent statement from IRPA that "for the nuclear industry and other non-medical sectors the use of a whole body dosimeter is considered likely to be sufficient for the majority of workers". © 2017 IOP Publishing Ltd.

  12. A PLZT Novel Sensor with Pt Implanted for Biomedical Application: Cardiac Micropulses Detection on Human Skin

    OpenAIRE

    González-Morán, Carlos O.; Miranda-Hernández, José G.; Flores Cuautle, José de Jesús Agustín; Suaste-Gómez, Ernesto; Herrera-Hernández, Héctor

    2017-01-01

    Advances in sensors for biomedical applications have been a great motivation. In this research, a PLZT (lead lanthanum zirconate titanate) novel sensor with platinum wire implanted in its longitudinal section was developed through of the synthesis process based on powder technology. The raw materials as lead (PbO), lanthanum (La2O3), zircon (ZrO2), and titanium (TiO2) were used in the formation of the chemical composition (62.8% PbO, 4.5% La2O3, 24.2% ZrO2, and 8.5% TiO2). Then, these powders...

  13. Antioxidant activity of phenolic compounds in lentil seeds (Lens culinaris L.

    Directory of Open Access Journals (Sweden)

    Dragišić-Maksimović Jelena

    2010-01-01

    Full Text Available The antioxidant activities of methanol extracts of lentil seeds (Lens culinaris L. have been investigated in this work. Scarce reference data describe lentil seeds as rich in polyphenols, which are reported to exhibit bioactive properties due to their capability to reduce or quench reactive oxygen species. The content and composition of phenolics is highly dependent of the cultivars, environments/growth conditions and method of analysis. Therefore, this study is an effort in investigation of phenolics content and composition in lentil seeds trying to prove the contribution of identified phenolics to antioxidant capacity. HPLC measurements revealed that lentil seeds contain gallic acid, epicatechin, catechin, protocatechuic acid, rutin, p-coumaric acid and umbeliferone. Their DPPH radical scavenging activity was in descending order from gallic acid to umbeliferone. The presented results contribute to knowledge of the implications in dietary intake of phenolic compounds from lentil seeds.

  14. A PLZT Novel Sensor with Pt Implanted for Biomedical Application: Cardiac Micropulses Detection on Human Skin

    Directory of Open Access Journals (Sweden)

    Carlos O. González-Morán

    2017-01-01

    Full Text Available Advances in sensors for biomedical applications have been a great motivation. In this research, a PLZT (lead lanthanum zirconate titanate novel sensor with platinum wire implanted in its longitudinal section was developed through of the synthesis process based on powder technology. The raw materials as lead (PbO, lanthanum (La2O3, zircon (ZrO2, and titanium (TiO2 were used in the formation of the chemical composition (62.8% PbO, 4.5% La2O3, 24.2% ZrO2, and 8.5% TiO2. Then, these powders were submitted to mix-mechanical milling at high energy; cylindrical samples with the implant of the platinum wire were obtained with the load application. Finally, the compacted samples were sintered at 1200°C for 2 hours, then followed by a polarization potential of 1500 V/mm at 60°C to obtain a novel sensor. The density and porosity were evaluated using the Archimedes’ principle, while the mechanical properties such as fracture toughness value and Young’s modulus were determined by indentation and ultrasonic methods, respectively. A microscopic examination was also carried out to investigate the structural properties of the material. The PLZT novel sensor is electronically arranged for monitoring the cardiac pulses through a data acquisition system. The results obtained in this research are analyzed and discussed.

  15. The Influence of Fabrication Conditions on the Physical Properties of PLZT:Nd3+ Ceramics

    Directory of Open Access Journals (Sweden)

    Płonska M.

    2013-12-01

    Full Text Available Celem niniejszej pracy było zbadanie wpływu warunków wytwarzania i zastosowanej domieszki neodymu na właściwości fizyczne ceramiki (Pbo.98Lao.o2(Zro.65Tio.35o.9s03, określanej mianem PLZT:Nd3+. Wszystkie proszki przygotowanych składów syntetyzowano metodą konwencjonalną, z tlenków o wysokiej czystości (>99.9%. Próbki ceramiczne zagęszczano techniką swobodnego spiekania i jednoosiowego prasowania na gorąco. Wykonane badania dały szczegółowy opis zależności między stosowaną domieszką oraz przyjętymi warunkami wytwarzania oraz wpływu na dielektryczne i optyczne właściwości otrzyma- nych materiałów ceramicznych. Optymalne warunki przygotowania PLZT:Nd3+, jak również zastosowane stężenia aktywatora Nd3+ zostały określone w odniesieniu do potencjalnych zastosowań optoelektronicznych.

  16. Exploring pH-Sensitive Hydrogels Using an Ionic Soft Contact Lens: An Activity Using Common Household Materials

    Science.gov (United States)

    Chen, Yueh-Huey; He, Yu-Chi; Yaung, Jing-Fun

    2014-01-01

    Hydrogels of the so-called smart polymers or environment-sensitive polymers are important modern biomaterials. Herein, we describe a hands-on activity to explore the pH-responsive characteristics of hydrogels using a commercially available ionic soft contact lens that is a hydrogel of poly(2-hydroxyethyl methacrylate-"co"-methacrylic…

  17. The preferentially magnified active nucleus in IRAS F10214+4724 - I. Lens model and spatially resolved radio emission

    Science.gov (United States)

    Deane, R. P.; Rawlings, S.; Marshall, P. J.; Heywood, I.; Klöckner, H.-R.; Grainge, K.; Mauch, T.; Serjeant, S.

    2013-03-01

    This is the first paper in a series that presents a multiwavelength analysis of the archetype ultraluminous infrared galaxy IRAS F10214+4724, a gravitationally lensed, starburst/active galactic nucleus at z = 2.3. Here we present a new lens model and spatially resolved radio data, as well as a deep Hubble Space Telescope (HST) F160W map. The lens modelling employs a Bayesian Markov chain Monte Carlo algorithm with extended source, forward ray tracing. Using these high-resolution HST, Multi-Element Radio Linked Interferometer Network (MERLIN) and Very Large Array (VLA) maps, the algorithm allows us to constrain the level of distortion to the continuum spectral energy distribution resulting from emission components with differing magnification factors, due to their size and proximity to the caustic. Our lens model finds that the narrow-line region, and by proxy the active nucleus, is preferentially magnified. This supports previous claims that preferential magnification could mask the expected polycyclic aromatic hydrocarbon spectral features in the Spitzer mid-infrared spectrum which roughly trace the star-forming regions. Furthermore, we show that the arc-to-counter-image flux ratio is not a good estimate of the magnification in this system, despite its common use in the IRAS F10214+4724 literature. Our lens modelling suggests magnifications of μ ˜ 15-20 ± 2 for the HST F814W, MERLIN 1.7 GHz and VLA 8 GHz maps, significantly lower than the canonical values of μ = 50-100 often used for this system. Systematic errors such as the dark matter density slope and colocation of stellar and dark matter centroids dominate the uncertainties in the lens model at the 40 per cent level.

  18. Nonlinear analysis of 0-3 polarized PLZT microplate based on the new modified couple stress theory

    Science.gov (United States)

    Wang, Liming; Zheng, Shijie

    2018-02-01

    In this study, based on the new modified couple stress theory, the size- dependent model for nonlinear bending analysis of a pure 0-3 polarized PLZT plate is developed for the first time. The equilibrium equations are derived from a variational formulation based on the potential energy principle and the new modified couple stress theory. The Galerkin method is adopted to derive the nonlinear algebraic equations from governing differential equations. And then the nonlinear algebraic equations are solved by using Newton-Raphson method. After simplification, the new model includes only a material length scale parameter. In addition, numerical examples are carried out to study the effect of material length scale parameter on the nonlinear bending of a simply supported pure 0-3 polarized PLZT plate subjected to light illumination and uniform distributed load. The results indicate the new model is able to capture the size effect and geometric nonlinearity.

  19. Neutron imaging and prompt gamma activation analysis using a monolithic capillary neutron lens

    International Nuclear Information System (INIS)

    Chen-Mayer, H.Heather; Lamaze, George P.; Mildner, David F.R.; Zeisler, Rolf; Gibson, Walter M.

    2002-01-01

    Neutron focusing lenses have been shown to enhance the measurement capabilities of prompt gamma activation analysis (PGAA) for small samples (∼100 μm in size) using a reactor-based cold neutron beam. As reported in our earlier work, a cold neutron beam emerging from a 58 Ni-coated guide, cross section 50 mm x 45 mm, is compressed to a spot size of about 0.54 mm (FWHM). In the current work, we report preliminary prompt gamma measurements performed with a monolithic capillary lens that accepts a 10 mm (hexagon flat-to-flat) size beam and focuses it to a spot size of 40. The smaller focal spot size enables better spatial resolution, but also makes sample alignment more challenging. We have added a neutron imaging technique to the sample positioning procedure that takes advantage of the converging and subsequent diverging nature of the focused beam. The measurement sensitivity for a 2.6 μg Gd sample has improved by a factor of 34. In addition to rastering samples in the lateral plane, we have also explored the possibility of profiling the inhomogeneity of the sample in the direction along the beam axis. (author)

  20. Structure of a Highly Active Cephalopod S-crystallin Mutant: New Molecular Evidence for Evolution from an Active Enzyme into Lens-Refractive Protein.

    Science.gov (United States)

    Tan, Wei-Hung; Cheng, Shu-Chun; Liu, Yu-Tung; Wu, Cheng-Guo; Lin, Min-Han; Chen, Chiao-Che; Lin, Chao-Hsiung; Chou, Chi-Yuan

    2016-08-08

    Crystallins are found widely in animal lenses and have important functions due to their refractive properties. In the coleoid cephalopods, a lens with a graded refractive index provides good vision and is required for survival. Cephalopod S-crystallin is thought to have evolved from glutathione S-transferase (GST) with various homologs differentially expressed in the lens. However, there is no direct structural information that helps to delineate the mechanisms by which S-crystallin could have evolved. Here we report the structural and biochemical characterization of novel S-crystallin-glutathione complex. The 2.35-Å crystal structure of a S-crystallin mutant from Octopus vulgaris reveals an active-site architecture that is different from that of GST. S-crystallin has a preference for glutathione binding, although almost lost its GST enzymatic activity. We've also identified four historical mutations that are able to produce a "GST-like" S-crystallin that has regained activity. This protein recapitulates the evolution of S-crystallin from GST. Protein stability studies suggest that S-crystallin is stabilized by glutathione binding to prevent its aggregation; this contrasts with GST-σ, which do not possess this protection. We suggest that a tradeoff between enzyme activity and the stability of the lens protein might have been one of the major driving force behind lens evolution.

  1. 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.

  2. Pulsed laser deposition process of PLZT thin films using an infrared Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, T. [CCADET-UNAM, A.P. 70-186, Mexico D.F., C.P. 04510 (Mexico)]. E-mail: tupacgarcia@yahoo.com; Posada, E. de [IMRE-Physics Faculty, Havana University (Cuba); Bartolo-Perez, P. [CINVESTAV-IPN Unidad, Applied Physics Department, A.P. 73 Cordemex, Merida, Yuc. (Mexico); Programa de Corrosion del Golfo de Mexico, UAC, Compeche (Mexico); Pena, J.L. [CINVESTAV-IPN Unidad, Applied Physics Department, A.P. 73 Cordemex, Merida, Yuc. (Mexico); Diamant, R. [UAM-Unidad Iztapalapa, D.F. (Mexico); Calderon, F. [IMRE-Physics Faculty, Havana University (Cuba); Pelaiz, A. [IMRE-Physics Faculty, Havana University (Cuba)

    2006-03-15

    Pulsed laser depositions of PLZT thin films were performed using an Nd:YAG (1064 nm) laser. The growths took place in vacuum or in an oxygen background. Room temperature and 500 deg. C were the used substrate temperatures. The X-ray diffraction analysis revealed a preferential crystallographic orientation in the films grown at room temperature in vacuum. Such result is discussed. The velocity distribution functions of the species in the plasma plume were obtained from a time of flight study using optical emission spectroscopy. The maximums of these distributions functions fall around 10{sup 6} cm/s, equivalent to an energy range of 18-344 eV. Ionic species of heavy elements (like lead) achieved higher velocities than other lighter species. This result is linked to the creation of an accelerating spatial charge and to the thermal nature of the target material extraction that allows some elements to be released first than others. Chemical state variations of the elements present in the films were analyzed. Under these different growing conditions, lead chemical states varied the most.

  3. High Energy Storage Density and Impedance Response of PLZT2/95/5 Antiferroelectric Ceramics.

    Science.gov (United States)

    Li, Bi; Liu, Qiuxiang; Tang, Xingui; Zhang, Tianfu; Jiang, Yanping; Li, Wenhua; Luo, Jie

    2017-02-08

    (Pb 0.97 La 0.02 )(Zr 0.95 Ti 0.05 )O₃ (PLZT2/95/5) ceramics were successfully prepared via a solid-state reaction route. The dielectric properties were investigated in the temperature region of 26-650 °C. The dielectric diffuse anomaly in the dielectric relaxation was found in the high temperature region of 600-650 °C with increasing the measuring frequency, which was related to the dynamic thermal process of ionized oxygen vacancies generated in the high temperature. Two phase transition points were detected during heating, which were found to coexist from 150 to 200 °C. Electric field induced ferroelectric to antiferroelectric phase transition behavior of the (Pb 0.97 La 0.02 )(Zr 0.95 Ti 0.05 )O₃ ceramics was investigated in this work with an emphasis on energy storage properties. A recoverable energy-storage density of 0.83 J/cm³ and efficiency of 70% was obtained in (Pb 0.97 La 0.02 )(Zr 0.95 Ti 0.05 )O₃ ceramics at 55 kV/cm. Based on these results, (Pb 0.97 La 0.02 )(Zr 0.95 Ti 0.05 )O₃ ceramics with a large recoverable energy-storage density could be a potential candidate for the applications in high energy-storage density ceramic capacitors.

  4. Photoreactivity of biologically active compounds. VIII. Photosensitized polymerization of lens proteins by antimalarial drugs in vitro.

    Science.gov (United States)

    Kristensen, S; Wang, R H; Tønnesen, H H; Dillon, J; Roberts, J E

    1995-02-01

    The drugs commonly used in the treatment of malaria are photochemically unstable. Several of these compounds cause dermal and ocular toxic reactions that may be light induced. The in vitro photopolymerization of calf lens proteins in the presence of antimalarial drugs was studied as part of a screening of the photochemical properties and phototoxic capabilities of these compounds. The pseudo-first-order rate constant for the reaction was calculated, and related to the amount of light absorbed by the compounds in order to determine the relative photosensitizing effect of each drug. The reaction mechanisms were evaluated by adding a variety of quenchers to the reaction medium during irradiation. Based on the results obtained in this study and previous knowledge about the pharmacokinetic behavior of these compounds, several of the drugs investigated have to be considered as potential photosensitizers in the human lens, the retina and the skin.

  5. PLZT Electrooptic Ceramic Photonic Devices for Surface-Normal Operation in Trenches Cut Across Arrays of Optical Fiber

    Science.gov (United States)

    Hirabayashi, Katsuhiko

    2005-03-01

    Simple Pb_1-x La_x(Zr_y Ti_z)_1-x/4 O3 (PLZT) electrooptic ceramic photonic device arrays for surface-normal operation have been developed for application to polarization-controller arrays and Fabry-Pérot tunable filter arrays. These arrays are inserted in trenches cut across fiber arrays. Each element of the arrayed structure corresponds to one optical beam and takes the form of a cell. Each sidewall of the cell (width: 50-80 μm) is coated to form an electrode. The arrays have 16 elements at a pitch of 250 μm. The phase modulator has about 1 dB of loss and a half-wavelength voltage of 120 V. A cascade of two PLZT phase modulators (thickness: 300 μm), with each attached to a polyimide lambda/2 plate (thickness:15 μm), is capable of converting an arbitrary polarization to the transverse-electric (TE) or transverse-magnetic (TM) polarization. The response time is 1 μs. The Fabry-Pérot tunable filters have a thickness of 50 μm . The front and back surfaces of each cell are coated by 99%-reflective mirror. The free spectral range (FSR) of the filters is about 10 nm, tunable range is about 10 nm, loss is 2.2 dB, and finesse is 150. The tuning speed of these devices is high, taking only 1 μs.

  6. 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...

  7. Initial Observations and Activities of Curiosity's Mars Hand Lens Imager (MAHLI) at the Gale Field Site

    Science.gov (United States)

    Aileen Yingst, R.; Edgett, Kenneth; MSL Science Team

    2013-04-01

    The Mars Hand Lens Imager (MAHLI) is a 2-megapixel focusable macro lens color camera on the turret on the Mars Science Laboratory rover, Curiosity's, robotic arm. The investigation centers on stratigraphy, grain-scale texture, structure, mineralogy, and morphology. MAHLI acquires focused images at working distances of 2.1 cm to infinity; at 2.1 cm the scale is 14 µm/pixel; at 6.9 cm it is 31 µm/pixel, like the Spirit and Opportunity Microscopic Imagers (MI). Most MAHLI use during the first 100 Martian days (sols) was focused on instrument, rover, and robotic arm engineering check-outs and risk reduction, including (1) interrogation of an eolian sand shadow for suitability for scooping, decontamination of the sample collection and processing system (CHIMRA, Collection and Handling for In-Situ Martian Rock Analysis), and first solid sample delivery to the Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) instruments; (2) documentation of the nature of this sand; (3) verification that samples were delivered to SAM and passed through a 150 µm mesh and a 2 mm funnel throat in the CheMin inlet; (4) development of methods for future precision robotic arm positioning of MAHLI and the Alpha Particle X-Ray Spectrometer (APXS); and (5) use of MAHLI autofocus for range-finding to determine locations to position the scoop before each scooping event. Most Sol 0-100 MAHLI images were obtained at scales of 31-110 µm/pixel; some geologic targets were imaged at 21-31 µm/pixel. No opportunities to position the camera close enough to obtain 14-20 µm/pixel images were available during this initial period. Only two rocks, named Jake Matijevic and Bathurst Inlet, were imaged at a resolution higher than MI. Both were dark gray and mantled with dust and fine/very fine sand. In both cases, the highest resolution images of these rocks show no obvious, indisputable grains, suggesting that grain sizes (as expressed at the rock surfaces) are sieved (≤ 150 µm) and

  8. SU-E-I-57: Estimating the Occupational Eye Lens Dose in Interventional Radiology Using Active Personal Dosimeters Worn On the Chest

    International Nuclear Information System (INIS)

    Omar, A; Marteinsdottir, M; Kadesjo, N; Fransson, A

    2015-01-01

    Purpose: To provide a general formalism for determination of occupational eye lens dose based on the response of an active personal dosimeter (APD) worn at chest level above the radiation protection apron. Methods: The formalism consists of three factors: (1) APD conversion factor converting the reading at chest level (APDchest) to the corresponding personal dose equivalent at eye level, (2) Dose conversion factor transferring the measured dose quantity, Hp(10), into a dose quantity relevant for the eye lens dose, (3) Correction factor accounting for differences in exposure of the eye(s) compared to the exposure at chest level (e.g., due to protective lead glasses).The different factors were investigated and evaluated based on phantom and clinical measurements performed in an x-ray angiography suite for interventional cardiology. Results: The eye lens dose can be conservatively estimated by assigning an appropriate numerical value to each factor entering the formalism that in most circumstances overestimates the dose. Doing so, the eye lens dose to the primary operator and assisting staff was estimated in this work as D-eye,primary = 2.0 APDchest and D-eye,assisting = 1.0 APDchest, respectively.The annual eye lens dose to three nurses and one cardiologist was estimated to be 2, 2, 2, and 13 mSv (Hp(0.07)), respectively, using a TLD dosimeter worn at eye level. In comparison, using the formalism and APDchest measurements, the respective doses were 2, 2, 2, and 16 mSv (Hp(3)). Conclusion: The formalism outlined in this work can be used to estimate the occupational eye lens dose from the response of an APD worn on the chest. The formalism is general and could be applied also to other types of dosimeters. However, the numerical value of the different factors may differ from those obtained with the APD’s used in this work due to differences in dosimeter properties

  9. Food as Social Justice: Critical Ethnography as a Lens for Communication Activism

    Science.gov (United States)

    Louis, Ross

    2016-01-01

    Courses: Public Speaking. Objectives: This semester-long service-learning activity examines access to affordable healthy food as a social justice issue, using critical ethnography as a framework to help students understand the link between activism and public speaking skills. After completing the project, students will be able to: (1) develop a…

  10. Flowering and Growth Responses of Cultivated Lentil and WildLensGermplasm toward the Differences in Red to Far-Red Ratio and Photosynthetically Active Radiation.

    Science.gov (United States)

    Yuan, Hai Y; Saha, Shyamali; Vandenberg, Albert; Bett, Kirstin E

    2017-01-01

    Understanding environmental responses of pulse crop species and their wild relatives will play an important role in developing genetic strategies for crop improvement in response to changes in climate. This study examined how cultivated lentil and wild Lens germplasm responded to different light environments, specifically differences in red/far-red ratio (R/FR) and photosynthetically active radiation (PAR). Three genotypes of each the seven Lens species were grown in environmentally controlled growth chambers equipped to provide light treatments consisting of different R/FR ratios and PAR values. Our results showed that overall, days to flower of Lens genotypes were mainly influenced by the R/FR induced light quality change but not by the PAR related light intensity change. The cultivated lentil ( L. culinaris ) showed consistent, accelerated flowering in response to the low R/FR light environment together with three wild lentil genotypes ( L. orientalis IG 72611, L. tomentosus IG 72830, and L. ervoides IG 72815) while most wild lentil genotypes had reduced responses and flowering time was not significantly affected. The longest shoot length, longest internode length, and largest leaflet area were observed under the low R/FR low PAR environment for both cultivated and wild lentils. The distinctly different responses between flowering time and elongation under low R/FR conditions among wild Lens genotypes suggests discrete pathways controlling flowering and elongation, which are both components of shade avoidance responses. The yield and above-ground biomass of Lens genotypes were the highest under high R/FR high PAR conditions, intermediate under low R/FR low PAR conditions, and lowest under high R/FR low PAR light conditions. Three L. lamottei genotypes (IG 110809, IG 110810, and IG 110813) and one L. ervoides genotype (IG 72646) were less sensitive in their time to flower responses while maintaining similar yield, biomass, and harvest index across all three light

  11. A Role for Calcium-Activated Adenylate Cyclase and Protein Kinase A in the Lens Src Family Kinase and Na,K-ATPase Response to Hyposmotic Stress.

    Science.gov (United States)

    Shahidullah, Mohammad; Mandal, Amritlal; Delamere, Nicholas A

    2017-09-01

    Na,K-ATPase activity in lens epithelium is subject to control by Src family tyrosine kinases (SFKs). Previously we showed hyposmotic solution causes an SFK-dependent increase in Na,K-ATPase activity in the epithelium. Here we explored the role of cAMP in the signaling mechanism responsible for the SFK and Na,K-ATPase response. Intact porcine lenses were exposed to hyposmotic Krebs solution (200 mOsm) then the epithelium was assayed for cAMP, SFK phosphorylation (activation) or Na,K-ATPase activity. An increase of cAMP was observed in the epithelium of lenses exposed to hyposmotic solution. In lenses exposed to hyposmotic solution SFK phosphorylation in the epithelium approximately doubled as did Na,K-ATPase activity and both responses were prevented by H89, a protein kinase A inhibitor. The magnitude of the SFK response to hyposmotic solution was reduced by a TRPV4 antagonist HC067047 added to prevent TRPV4-mediated calcium entry, and by a cytoplasmic Ca2+ chelator BAPTA-AM. The Na,K-ATPase activity response in the epithelium of lenses exposed to hyposmotic solution was abolished by BAPTA-AM. As a direct test of cAMP-dependent SFK activation, intact lenses were exposed to 8-pCPT-cAMP, a cell-permeable cAMP analog. 8-pCPT-cAMP caused robust SFK activation. Using Western blot, two calcium-activated adenylyl cyclases, ADCY3 and ADCY8, were detected in lens epithelium. Calcium-activated adenylyl cyclases are expressed in the lens epithelium and SFK activation is linked to a rise of cAMP that occurs upon hyposmotic challenge. The findings point to cAMP as a link between TRPV4 channel-mediated calcium entry, SFK activation, and a subsequent increase of Na,K-ATPase activity.

  12. INHIBITORY ACTIVITY OF FLAVONOIDS ON THE LENS ALDOSE REDUCTASE OF HEALTHY AND DIABETIC RATS

    Directory of Open Access Journals (Sweden)

    M. T. Goodarzi

    2006-05-01

    Full Text Available Aldose reductase is a critical enzyme in the polyol pathway that plays an important role in diabetes mellitus. Inhibition of the activity of this enzyme can prevent cataract in diabetic patients’lenses. In this study the inhibitory effect of two flavonoids, quercetin and naringin, in the activity of aldose reductase in streptozotocin-induced diabetic and healthy rats were investigated. Thirty male rats were divided in six groups. The first, second and third group were healthy rats that received water,quercetin and naringin, respectively. The fourth, fifth and sixth groups were streptozocin-induced diabetic rats that received water, quercetin and naringin, respectively. These rats were fed orally in a definite dose from each substance for 12 days. After this period rats were scarified and their lenses were separated and homogenized. The activity of aldose reductase was measured in each homogenized sample separately. The effect of feeding of these substances in blood sugar was also determined. Aldose reductase activity was reduced 73 and 69 percent in diabetic rats fed by quercetin and naringin, respectively, and the difference compared to control group was significant. In healthy rats this reduction was 63 and 59 percent, respectively, and the difference was significant compared to those who did not receive flavonoids. It was concluded that these substances were effective in reduction of aldose reductase activity in vivo and consequently could delay the progress of cataract.

  13. 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

  14. 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.

  15. 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

  16. Activity systems modeling as a theoretical lens for social exchange studies

    Directory of Open Access Journals (Sweden)

    Ernest Jones

    2016-01-01

    Full Text Available The social exchange perspective seeks to acknowledge, understand and predict the dynamics of social interactions. Empirical research involving social exchange constructs have grown to be highly technical including confirmatory factor analysis to assess construct distinctiveness and structural equation modeling to assess construct causality. Each study seemingly strives to assess how underlying social exchange theoretic constructs interrelate. Yet despite this methodological depth and resultant explanatory and predictive power, a significant number of studies report findings that, once synthesized, suggest an underlying persistent threat of conceptual or construct validity brought about by a search for epistemological parsimony. Further, it is argued that a methodological approach that embraces inherent complexity such as activity systems modeling facilitates the search for simplified models while not ignoring contextual factors.

  17. Antibacterial Activity of Silver Nanoparticle-Loaded Soft Contact Lens Materials: The Effect of Monomer Composition.

    Science.gov (United States)

    Shayani Rad, Maryam; Khameneh, Bahman; Sabeti, Zahra; Mohajeri, Seyed Ahmad; Fazly Bazzaz, Bibi Sedigheh

    2016-10-01

    In the present work, the effect of monomer composition on silver nanoparticles' (SNPs) binding capacity of hydrogels was investigated and their antibacterial efficacy was evaluated. Three series of poly-hydroxyethyl methacrylate (HEMA) hydrogels were prepared using methacrylic acid (MAA), methacrylamide (MAAM), and 4-vinylpyridine (4VP) as co-monomers, and ethylene glycol dimethacrylate (EGDMA) as cross-linker. SNPs binding capacity of hydrogels was evaluated in different concentrations (2, 10, and 20 ppm). In vitro antibacterial activity of SNP-loaded hydrogels was studied against Pseudomonas aeruginosa (P. aeruginosa) isolated from patients' eyes. Then, inhibitory effect of hydrogels in biofilm formation was evaluated in the presence of Staphylococcus epidermidis (S. epidermidis) (DSMZ 3270). Our data indicated that poly(HEMA-co-MAA-co-EGDMA) had superior binding affinity for SNPs in comparison with other hydrogels. All SNP-loaded hydrogels demonstrated excellent antimicrobial effects at all times against P. aeruginosa and S. epidermidis after soaking in 10 and 20 ppm SNP suspensions. Scanning electron microscope (SEM) images revealed excellent inhibitory effect of SNPs against biofilm formation on the surface of the hydrogels. This study indicated the effect of monomer compositions in SNP loading capacity of poly(HEMA) hydrogels and antibacterial efficacy of SNP-loaded hydrogels against P. aeruginosa and S. epidermidis, but further in vivo evaluation is necessary.

  18. Through an activity theory lens: Conceptualizing service learning as 'boundary work'

    Directory of Open Access Journals (Sweden)

    Janice McMillan

    2009-11-01

    Full Text Available Michael Gibbons (2005 has spoken about the need to re-imagine the relationship between higher education and society and he calls for the emergence of a ‘new social contract’. In particular he highlights three elements of this new form of engagement: contextualization, boundary objects, and transaction spaces or boundary zones. It is here that my paper is located – in the conceptualization of the ‘boundary zone’ at the nexus of higher education and society, with a focus on service learning as practice. In the literature on higher education there appears to be little evidence describing ways of conceptualizing and understanding the boundary zone itself. Most of the service learning research literature for instance, looks either at the university side of the relationship or at the impact on the community (and even then only in very few cases. In order to better understand the ‘push and pull’ of service learning, we need to better understand better what happens in the transaction/boundary zone in the first instance. In order to do this, we need to develop conceptual tools to illuminate the complex practices that occur at this nexus. Drawing on situated learning, post Vygotskian theory and activity theory in particular, I develop a framework for service learning conceived as ‘boundary work’. This framework illuminates inherent contradictions in these trans-boundary practices, and the argument is therefore that unless we understand these practices better and in more nuanced ways, we are in no position to improve them and consequently our understandings of this form of educational practice remain unaltered. Finally, by raising a number of questions about boundary practices at the end of the paper, I provide some ways of taking this conceptualization project further.

  19. 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,

  20. Materiais cerâmicos ferroelétricos como hospedeiros para íons laser ativos: características estruturais, microestruturais e espectroscópicas Ferroelectric ceramic materials as hosts of laser active ions: structural, microstructural and spectroscopic characteristics

    Directory of Open Access Journals (Sweden)

    A. S. S. de Camargo

    2004-12-01

    Full Text Available Cerâmicas ferroelétricas transparentes de titanato zirconato de chumbo modificado com lantânio (PLZT, com La/Zr/Ti=9/65/35 e dopadas com íons terras raras (TR = Nd3+, Er3+, Yb3+, Tm3+ e Ho3+ foram preparadas por prensagem uniaxial a quente com o objetivo de investigar a sua qualificação como materiais laser ativos. Com este propósito foram feitas caracterizações estruturais, microestruturais, elétricas e espectroscópicas. Para a dopagem com 1% em peso de óxido TR2O3, verificou-se uma forte influência do tipo de íon terra rara nas características ferroelétricas e óticas do material hospedeiro. Observou-se ainda que a incorporação de Nd3+ nos sítios de Pb2+/La3+ reduziu a temperatura de transição ferro-paraelétrica e favoreceu significativamente a transparência dos corpos cerâmicos. Medidas de espectroscopia ótica revelaram a potencialidade do PLZT: Nd3+ como um meio ativo para a construção de lasers bombeados por lasers de diodo, na região do infravermelho próximo. Os sistemas PLZT:Er3+ e PLZT:Tm3+ poderão também se tornar materiais interessantes para esse fim.In this work, transparent ferroelectric ceramics of lanthanum modified lead zirconate titanate (PLZT, with La/Zr/Ti=9/65/35, doped with rare-earth ions (RE = Nd3+, Er3+, Yb3+ Tm3+ and Ho3+, were processed by hot uniaxial pressing aiming the investigation of their potentiality as near-infrared laser active media. Their structural, microstructural, electric and spectroscopic characterizations were performed. For 1.0 wt.% RE2O3 doping, a strong influence of the rare-earth type was verified in the PLZT ferroelectric and optical characteristics. It was also observed that the Nd3+ substitution for Pb2+/La3+ reduces the ferro-paraelectric phase transition temperature and favors the transparency of the ceramic bodies. Spectroscopic analysis indicates that PLZT:Nd3+ is a potential diode-pumped laser active media in the near infrared region, and with some improvements

  1. 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 ...

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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...

  8. Activity of a melimine derived peptide Mel4 against Stenotrophomonas, Delftia, Elizabethkingia, Burkholderia and biocompatibility as a contact lens coating

    DEFF Research Database (Denmark)

    Dutta, Debarun; Zhao, Timothy; Cheah, Kai Bing

    2017-01-01

    investigated for changes in lens parameters. Safety of Mel-4 coated lenses were determined in a rabbit model of daily contralateral wear. A prospective, randomised, double-masked, contralateral, 1week daily wear human clinical trial was used to evaluate subjective responses and ocular physiology. Results Mel4......Purpose To determine the antimicrobial activity of the melimine derived peptide Mel4 against Delftia, Stenotrophomonas, Elizabethkingia, Burkholderia and to investigate biocompatibility of Mel4 as an antimicrobial coating on contact lenses in animals and humans. Methods In vitro antimicrobial...... wear. During human clinical trial, there were no differences between Mel4 coated and uncoated contact lenses in lens performance indicators and ocular signs such as corneal fluorescein staining. Mel4 and control uncoated lenses had no differences in ocular symptoms during lens wear. Conclusion Mel4 has...

  9. Displacement and emission currents from PLZT 8/65/35 and 4/95/5 excited by a negative voltage pulse at the rear electrode

    CERN Document Server

    Benedek, G; Handerek, J; Marchesini, S; De Martinis, C; Riege, H; Scurati, A

    1997-01-01

    It is shown that non-prepoled PLZT ceramics, both in ferroelectric and antiferroelectric phase, emit intense current bursts when a negative exciting voltage is applied to the rear surface of the cathode. The spontaneous polarization induced in the bulk by applying the field through the cathode disk, creates a sheet of negative charge on the diode boundary of the ferroelectric. This, in turn, induces such a high electric field at the diode dielectric surface that electrons are ejected out from the ceramic surface into the vacuum. The coherent behaviour of the displacement and emitted current shows clearly that the emission is due to a variation of spontaneous polarization. A second effect generated by the application of the high voltage pulse at the rear side is the formation of a surface plasma. Applying a positive voltage to the anode, electrons are readily transferred through the diode gap.

  10. Dielectric properties of PLZT-x/65/35 (2≤x≤13 under mechanical stress, electric field and temperature loading

    Directory of Open Access Journals (Sweden)

    K. Pytel

    2013-01-01

    Full Text Available We investigated the effect of uniaxial pressure (0÷1000 bars applied parallely to the ac electric field on dielectric properties of PLZT-x/65/35 (2≤x≤13 ceramics. There was revealed a significant effect of the external stress on these properties. The application of uniaxial pressure leads to the change of the peak intensity of the electric permittivity (ϵ, of the frequency dispersion as well as of the dielectric hysteresis. The peak intensity ϵ becomes diffused/sharpened and shifts to a higher/lower temperatures with increasing the pressure. It was concluded that the application of uniaxial pressure induces similar effects as increasing the Ti ion concentration in PZT system. We interpreted our results based on the domain switching processes under the action of combined electromechanical loading.

  11. Lens Aldose Reductase Inhibitory and Free Radical Scavenging Activity of Fractions of Chromolaena odorata (Siam Weed: Potential for Cataract Remediation

    Directory of Open Access Journals (Sweden)

    Emmanuel O. AJANI

    2016-09-01

    Full Text Available Searching for effective and safe aldose reductase (AR inhibitor agent is a major thrust area in the mainstream of anti-cataractogenic research. This study was set up to investigate the in vitro aldose reductase inhibitory (ARI activity of fractions of methanolic extract of Chromolaena odorata leaves, on partially purified AR from goat lens, for potential use in the development of anticataractogenic agent. The phyto-constituents of the leaves were screened in aqueous and methanolic extracts and the free radical scavenging activities of the fractions were evaluated. The kinetics of the enzyme in the presence of fractions of the leaves was then compared. Phenol, flavonoid, alkaloid, saponin, terpenoid, quinones and phlobatannins were detected in both extracts. All the fractions inhibited AR in an uncompetitive manner, showing a reduced V max and Km when compared with glyceraldehyde. ARI activity was found to be the highest with aqueous fraction (IC50, 0.22 ± 0.01 mg/ml. All other fractions showed mild to moderate AR inhibition capacity, while it was found to be the lowest within hexane fraction (IC50, 1.20 ± 0.10 mg/ml. All the fractions showed free radical scavenging activity and metal chelating activity. The study confirmed the ARI and antioxidant capacity of Chromolaena odorata which may be due to its phenolic constituents, indicating that the plant may serve as a base for the development of anticataract agent.

  12. Interim report of the JHPS expert committee on radiation protection of the lens of the eye (4). Current activities of ICRP and ICU: External dosimetric concepts for the lens of the eye

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Fujimichi, Yuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Yamauchi-Kawaura, Chiyo; Tsujimura, Norio; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2015-01-01

    The International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) have been defined operational quantities and protection quantities. Dose limits have been also recommended by the ICRP using protection quantities. These quantities and some related values for main radiation such as photons, electrons, and neutrons, are summarized in this article with some historical considerations. The ICRP indicated conversion coefficients for the lens of the eye as absorbed dose per fluence as protection quantities. equivalent dose is not used because a protection quantity that uses radiation weighting factors is not intended to be calculated for tissue reactions. So far, the ICRP has not indicated a specific RBE value for cataract formation. Operational quantities are used for measurements. There have been three types of phantoms, namely a slab phantom, a reduced phantom, and a cylindrical phantom, but none of them has been definitely recommended for the lens of the eye by the ICRP or the ICRU. Although conversion coefficients to personal dose equivalent, H p (3), for electrons have been recommended, no other conversion coefficients to personal dose equivalent for the lens of the eye has been indicated by the ICRP or the ICRU. However, there have been several studies described personal dose equivalent. Ambient dose equivalent, H * (3), and directional dose equivalent, H(3, α), have been indicated in several limited conditions by the ICRP and the ICRU. These status are overviewed in this article. (author)

  13. 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 ...

  14. 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. ...

  15. 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 ...

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. 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 ...

  20. 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 ...

  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 ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  2. 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 ...

  3. 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.

  4. 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 ...

  5. 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. " ...

  6. 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 ...

  7. 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 ...

  8. PLZT Microfibers Technology Optimization

    Directory of Open Access Journals (Sweden)

    Kozielski L.

    2016-09-01

    Full Text Available Electrocaloric (EC structures for a new generation of cooling or heating elements utilize the temperature dependence of spontaneous polarization in some ferroelectric materials to convert waste heat into electricity and vice versa. A (Pb0.93La0.07 (Zr0.65Ti0.35O3 material, have the largest recorded pyroelectric coefficient. An effective predicted form for such applications is fiber, due to small heat capacitance and quick response time, even for nano second laser excitation. Consequently, the presented work provides a description of the optimization of structural, ferroelectric and piezoelectric properties of obtained fibers, finally concluding on necessity of sintering temperature reduction in 100°C in contrast to bulk form to effectively prevent its destruction.

  9. 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

  10. LENS: Science Scope and Development Stages

    Science.gov (United States)

    Vogelaar, R. Bruce

    2013-04-01

    The Low-Energy Neutrino Spectroscopy (LENS) experiment will resolve the solar metallicity question via measurement of the CNO neutrino flux, as well as test the predicted equivalence of solar luminosity as measured by photon versus neutrinos. The LENS detector uses charged-current interaction of neutrinos on Indium-115 (loaded in a scintillator, InLS) to reveal the complete solar neutrino spectrum. LENS's optically segmented 3D lattice geometry achieves precise time and spatial resolution and unprecedented background rejection and sensitivity for low-energy neutrino events. This first-of-a-kind lattice design is also suited for a range of other applications where high segmentation and large light collection are required (eg: sterile neutrinos with sources, double beta decay, and surface detection of reactor neutrinos). The physics scope, detector design, and logic driving the microLENS and miniLENS prototyping stages will be presented. The collaboration is actively running programs; building, operating, developing, and simulating these prototypes using the Kimballton Underground Research Facility (KURF). New members are welcome to the LENS Collaboration, and interested parties should contact R. Bruce Vogelaar.

  11. Analysis of newspaper coverage of active aging through the lens of the 2002 World Health Organization Active Ageing Report: A Policy Framework and the 2010 Toronto Charter for Physical Activity: A Global Call for Action.

    Science.gov (United States)

    Abdullah, Boushra; Wolbring, Gregor

    2013-12-05

    As populations continue to grow older, efforts to support the process of aging well are important goals. Various synonyms are used to cover aging well, such as active aging. The World Health Organization published in 2002 the report Active Ageing: A Policy Framework that according to the call for papers, has brought active ageing to the forefront of international public health awareness. The 2010 Toronto Charter for Physical Activity: A Global Call for Action was singled out in the call for papers as a key document promoting physical activity one goal of the 2002 WHO active aging policy framework. Media are to report to the public topics of importance to them. We investigated the newspaper coverage of aging well and synonymous terms such as active aging through the lens of the 2002 WHO active aging policy framework and the 2010 Toronto Charter for Physical Activity. As sources we used the following newspapers: China Daily, The Star (Malaysia), two UK newspapers (The Guardian, The Times), a database of 300 Canadian newspapers (Canadian Newsstand) and a US newspaper (The New York Times). The study generated data answering the following four research questions: (1) how often are the 2002 WHO active aging policy framework and the 2010 Toronto Charter for Physical Activity mentioned; (2) how often is the topic of active aging and terms conveying similar content (aging well, healthy aging, natural aging and successful aging) discussed; (3) which of the issues flagged as important in the 2002 WHO active aging policy framework and the 2010 Toronto Charter for Physical Activity are covered in the newspaper coverage of active aging and synonymous terms; (4) which social groups were mentioned in the newspapers covered. The study found a total absence of mentioning of the two key documents and a low level of coverage of "active aging" and terms conveying similar content. It found further a lack of engagement with the issues raised in the two key documents and a low level of

  12. Analysis of Newspaper Coverage of Active Aging through the Lens of the 2002 World Health Organization Active Ageing Report: A Policy Framework and the 2010 Toronto Charter for Physical Activity: A Global Call for Action

    Directory of Open Access Journals (Sweden)

    Boushra Abdullah

    2013-12-01

    Full Text Available As populations continue to grow older, efforts to support the process of aging well are important goals. Various synonyms are used to cover aging well, such as active aging. The World Health Organization published in 2002 the report Active Ageing: A Policy Framework that according to the call for papers, has brought active ageing to the forefront of international public health awareness. The 2010 Toronto Charter for Physical Activity: A Global Call for Action was singled out in the call for papers as a key document promoting physical activity one goal of the 2002 WHO active aging policy framework. Media are to report to the public topics of importance to them. We investigated the newspaper coverage of aging well and synonymous terms such as active aging through the lens of the 2002 WHO active aging policy framework and the 2010 Toronto Charter for Physical Activity. As sources we used the following newspapers: China Daily, The Star (Malaysia, two UK newspapers (The Guardian, The Times, a database of 300 Canadian newspapers (Canadian Newsstand and a US newspaper (The New York Times. The study generated data answering the following four research questions: (1 how often are the 2002 WHO active aging policy framework and the 2010 Toronto Charter for Physical Activity mentioned; (2 how often is the topic of active aging and terms conveying similar content (aging well, healthy aging, natural aging and successful aging discussed; (3 which of the issues flagged as important in the 2002 WHO active aging policy framework and the 2010 Toronto Charter for Physical Activity are covered in the newspaper coverage of active aging and synonymous terms; (4 which social groups were mentioned in the newspapers covered. The study found a total absence of mentioning of the two key documents and a low level of coverage of “active aging” and terms conveying similar content. It found further a lack of engagement with the issues raised in the two key documents and a

  13. Study of preparations of bee pollen extracts, antioxidant and antibacterial activity Estudo das preparações de extratos de pólen apícola, atividade antioxidante e antibacteriana

    Directory of Open Access Journals (Sweden)

    Solange Teresinha Carpes

    2007-12-01

    Full Text Available The aim of this study was to determine the antioxidant activity, phenolic content and antibacterial activity of pollen extracts obtained with different concentrations of ethanol. Each extraction condition (ethanol solutions from 40 to 90% had a different effect in the phenolic compounds content. Although, the pollen extract obtained at 60, 70 and 80% of ethanol showed relatively higher levels of phenolic compounds (>10 mg/g and did not present statistical significant difference between the extraction conditions. The amount of total phenolics ranged from 3.6 to 8.1 and 6.6 to 10.9 mg GAE/g for Alagoas state and Parana state pollen, respectively. The higher value for antioxidant activity index was 83.30% for the pollen from Alagoas state and 81.15 % for Parana state pollen. The highest degree of antioxidant activity was found in the extraction at 60% of ethanol solution for Parana state pollen, which also showed the highest concentration of polyphenol compounds. Staphylococcus aureus was inhibited by the ethanolic extract of Alagoas state pollen in all the concentrations of solvent, except the ethanolic extract of pollen at 90%. The extract at 60% of ethanol solution (Parana sample inhibited Bacillus subtilis, Pseudomonas aeruginosa and Klebsiella sp.Objetivou-se, neste estudo determinar compostos fenólicos, a atividade antioxidante a antibacteriana dos extratos etanólicos de pólen, obtidos com diferentes concentrações de etanol. As diferentes condições de extração (etanol de 40 a 90% apresentaram diferentes efeitos no conteúdo dos compostos fenólicos extraídos. Os extratos de pólen obtidos com etanol a 60, 70 e 80% apresentaram maiores níveis de compostos fenólicos (>10 mg/g e não apresentaram diferenças estatísticas entre essas condições de extração. A quantidade de compostos fenólicos nos extratos de pólen variou de 3.6 a 8.1 e 6.6 a 11 mg de equivalente em ácido gálico por g de pólen (GAE, para os estados de Alagoas

  14. Sterilization potential of contact lens solutions

    Directory of Open Access Journals (Sweden)

    Dada Vijay

    1988-01-01

    Full Text Available In a dynamic field of Contact Lens Solutions maintenance of high standards of anti-microbial activity is a must Resterilization Activity Time′ is a universally accepted yardstick for such an evaluation. In this study eight brands of indigenous popular solutions alongwith two FDA approved solutions were tested for their sterilization efficacy: Standardized suspensions of Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus fumigatus were used for the purpose. It was observed that the contact lens solutions available ir, the domestic market were not upto the mark Suggestions for improvement have also been made.

  15. Understanding Task-in-Process through the Lens of Laughter: Activity Designs, Instructional Materials, Learner Orientations, and Interpersonal Relationships

    Science.gov (United States)

    Hasegawa, Atsushi

    2018-01-01

    Using the framework of conversation analysis, this study investigated the interactional workings of laughter in task-based interactions. The analysis was drawn from 160 cases of pair work interactions, collected in 2nd-semester Japanese-as-a-foreign-language classrooms. The pair work activities examined in this study are mostly grammar-focused,…

  16. 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

  17. Addendum report of the JHPS expert committee on radiation protection of the lens of the eye (3). Recent related overseas activities

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Kawaura, Chiyo; Tsujimura, Norio; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2015-01-01

    Following the Statement on Tissue Reaction issued by the International Commission on Radiological Protection (ICRP), revisions and discussions are underway in various international organizations about the standards, guidelines and methods for the eye dosimetry. We have previously discussed these issues in six interim reports, followed by two addendum reports on lens dosimetry. This addendum report reviews ongoing overseas discussion and work in relation to research on radiogenic cataracts and implementation of the new eye lens dose limit, such as those in the European Commission, Low Dose Research towards Multidisciplinary Integration (DoReMi), Open Project for European Radiation Research Area (OPERRA), and the Unite Sates National Council on Radiation Protection and Measurements (NCRP). This report serves as the last part of a series of reports by the Japan Health Physics Society Expert Committee on Radiation Protection of the Lens of the Eye. (author)

  18. 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

  19. 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 ...

  20. 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 ...

  1. 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

  2. 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…

  3. 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 ...

  4. 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.

  5. 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.

  6. 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 ...

  7. 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

  8. 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.

  9. 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.

  10. Effect of infrared radiation on the lens

    Directory of Open Access Journals (Sweden)

    Aly Eman

    2011-01-01

    Full Text Available Background: Infrared (IR radiation is becoming more popular in industrial manufacturing processes and in many instruments used for diagnostic and therapeutic application to the human eye. Aim : The present study was designed to investigate the effect of IR radiation on rabbit′s crystalline lens and lens membrane. Materials and Methods: Fifteen New Zealand rabbits were used in the present work. The rabbits were classified into three groups; one of them served as control. The other two groups were exposed to IR radiation for 5 or 10 minutes. Animals from these two irradiated groups were subdivided into two subgroups; one of them was decapitated directly after IR exposure, while the other subgroup was decapitated 1 hour post exposure. IR was delivered from a General Electric Lamp model 250R 50/10, placed 20 cm from the rabbit and aimed at each eye. The activity of Na + -K + ATPase was measured in the lens membrane. Soluble lens proteins were extracted and the following measurements were carried out: estimation of total soluble protein, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE and Fourier transform infrared (FTIR spectroscopy. For comparison between multiple groups, analysis of variance was used with significance level set at P < 0.001. Results: The results indicated a change in the molecular weight of different lens crystalline accompanied with changes in protein backbone structure. These changes increased for the groups exposed to IR for 10 minutes. Moreover, the activity of Na + -K + ATPase significantly decreased for all groups. Conclusions: The protein of eye lens is very sensitive to IR radiation which is hazardous and may lead to cataract.

  11. [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.

  12. 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.

  13. 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

  14. Sterilization potential of contact lens solutions

    OpenAIRE

    Dada Vijay; Mehta Manoj

    1988-01-01

    In a dynamic field of Contact Lens Solutions maintenance of high standards of anti-microbial activity is a must Resterilization Activity Time′ is a universally accepted yardstick for such an evaluation. In this study eight brands of indigenous popular solutions alongwith two FDA approved solutions were tested for their sterilization efficacy: Standardized suspensions of Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus fumigatus were used for the purpose. ...

  15. Effects of x-irradiation on lens reducing systems. [Rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Giblin, F.J.; Chakrapani, B.; Reddy, V.N.

    1978-01-01

    Studies have been made of the effects of x ray on various lens reducing systems including the levels of NADPH and glutathione (GSH), the activity of the hexose monophosphate shunt (HMS), and the activities of certain enzymes including glutathion reductase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase (G-6-PD). It was found that during several weeks following x irradiation but prior to cataract formation there was very little change in the number of reduced -SH groups per unit weight of lens protein but that, with the appearance of cataract, there was a sudden loss of protein -SH groups. In contrast, the concentration of GSH in the x-rayed lens decreased throughout the experimental period. Similarly, the concentration of NADPH in the x-rayed lens was found to decrease significantly relative to controls one week prior to cataract formation and the ratio of NADPH to NADP/sup +/ in the lens shifted at this time period from a value greater than 1.0 in the control lens to less than 1.0 in the x-rayed lens. A corresponding decrease occurred in the activity of the HMS in x-rayed lenses as measured by culture in the presence of 1-/sup 14/C-labelled glucose. G-6-PD was partially inactivated in the x-rayed lens. Of the eight enzymes studied, G-6-PD appeared to be the most sensitive to x-irradiation. The data indicate that x-irradiation results in a steady decrease in the effectiveness of lens reducing systems and that, when these systems reach a critically low point, sudden oxidation of protein -SH groups and formation of high molecular weight protein aggregates may be initiated.

  16. Effects of x-irradiation on lens reducing systems

    International Nuclear Information System (INIS)

    Giblin, F.J.; Chakrapani, B.; Reddy, V.N.

    1978-01-01

    Studies have been made of the effects of x ray on various lens reducing systems including the levels of NADPH and glutathione (GSH), the activity of the hexose monophosphate shunt (HMS), and the activities of certain enzymes including glutathion reductase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase (G-6-PD). It was found that during several weeks following x irradiation but prior to cataract formation there was very little change in the number of reduced -SH groups per unit weight of lens protein but that, with the appearance of cataract, there was a sudden loss of protein -SH groups. In contrast, the concentration of GSH in the x-rayed lens decreased throughout the experimental period. Similarly, the concentration of NADPH in the x-rayed lens was found to decrease significantly relative to controls one week prior to cataract formation and the ratio of NADPH to NADP + in the lens shifted at this time period from a value greater than 1.0 in the control lens to less than 1.0 in the x-rayed lens. A corresponding decrease occurred in the activity of the HMS in x-rayed lenses as measured by culture in the presence of 1- 14 C-labelled glucose. G-6-PD was partially inactivated in the x-rayed lens. Of the eight enzymes studied, G-6-PD appeared to be the most sensitive to x-irradiation. The data indicate that x-irradiation results in a steady decrease in the effectiveness of lens reducing systems and that, when these systems reach a critically low point, sudden oxidation of protein -SH groups and formation of high molecular weight protein aggregates may be initiated

  17. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. [Seoul National University Hospital (Korea, Republic of)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  18. TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionists

    Energy Technology Data Exchange (ETDEWEB)

    Rehani, M. [Massachusetts General Hospital (United States)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  19. 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 ...

  20. 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.

  1. 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)

  2. Development of high precision and cryogenic lens holders

    Science.gov (United States)

    Reutlinger, A.; Boesz, Anton; Mottaghibonab, A.; Eckert, P.; Dubowy, M.; Gebler, H.; Grupp, F.; Geis, N.; Bode, A.; Katterloher, R.; Bender, R.

    2017-11-01

    The optical system of the Near Infrared Spectrometer and Photometer (NISP) of the EUCLID mission consists mainly of a filter and grism wheel and 4 aspherical lenses with large diameters up to 170 mm. The single lenses require a high precision positioning at the operational temperature of 150 K. An additional design driver represents the CaF2 material of a lens, which is very sensitive wrt brittleness. The technical maturity of the combination of single features such as CaF2, large diameter (and mass), high precision and cryogenic conditions is considered as low. Therefore, a dedicated pre-development program has been launched to design and develop a first prototype of lens holder and to demonstrate the functional performance at representative operational conditions. The 4 lenses are divided into 3x lenses for the Camera Lens Assembly (CaLA) and 1x lens for the Corrector Lens Assembly (CoLA). Each lens is glue mounted onto solid state springs, part of an adaption ring. The adaption ring shall provide protection against vibration loads, high accuracy positioning, as well as quasi load free mounting of the lens under operational conditions. To reduce thermomechanical loads on the lens, the CTE of the adaption ring is adapted to that of the lens. The glue between lens and solid state spring has to withstand high tension loads during vibration. At the operational temperature the deviating CTE between glue and lens/adaption ring introduces shear loads into the glue interface, which are critical, in particular for the fragile CaF2 lens material. For the case of NISP the shear loads are controlled with the glue pad diameter and the glue thickness. In the context of the development activity many technology aspects such as various solid state spring designs, glue selection and glue handling have been investigated. A parametric structural model was developed to derive the specific design feature of each ring, such as spring force, number of springs, eigenfrequency, etc. This

  3. LAUE lens development at UC Berkeley: status and prospects

    Science.gov (United States)

    Barrière, Nicolas M.; Tomsick, John A.; Ackermann, Marcelo D.; Bastie, Pierre; Boggs, Steven E.; Hanlon, Lorraine; Jentschel, Michael; Lowell, Alexander; Roudil, Gilles; von Ballmoos, Peter; Wade, Colin

    2013-09-01

    We report on the status of the Laue lens development effort led by UC Berkeley, where a dedicated X-ray beamline and a Laue lens assembly station were built. This allowed the realization of a first lens prototype in June 2012. Based on this achievement, and thanks to a new NASA APRA grant, we are moving forward to enable Laue lenses. Several parallel activities are in progress. Firstly, we are refining the method to glue quickly and accurately crystals on a lens substrate. Secondly, we are conducting a study of high-Z crystals to diffract energies up to 900 keV efficiently. And thirdly, we are exploring new concepts of Si-based lenses that could further improve the focusing capabilities, and thus the sensitivity of Laue lenses.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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...

  9. 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...

  10. 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

  11. Dynamic metasurface lens based on MEMS technology

    Directory of Open Access Journals (Sweden)

    Tapashree Roy

    2018-02-01

    Full Text Available In the recent years, metasurfaces, being flat and lightweight, have been designed to replace bulky optical components with various functions. We demonstrate a monolithic Micro-Electro-Mechanical System (MEMS integrated with a metasurface-based flat lens that focuses light in the mid-infrared spectrum. A two-dimensional scanning MEMS platform controls the angle of the lens along two orthogonal axes by ±9°, thus enabling dynamic beam steering. The device could be used to compensate for off-axis incident light and thus correct for aberrations such as coma. We show that for low angular displacements, the integrated lens-on-MEMS system does not affect the mechanical performance of the MEMS actuators and preserves the focused beam profile as well as the measured full width at half maximum. We envision a new class of flat optical devices with active control provided by the combination of metasurfaces and MEMS for a wide range of applications, such as miniaturized MEMS-based microscope systems, LIDAR scanners, and projection systems.

  12. Laboratory Demonstration of Axicon-Lens Coronagraph

    Science.gov (United States)

    Choi, Jaeho; Jea, Geonho

    2018-01-01

    The results of laboratory based experiments of the proposed coronagraph using axicon-lenses that is conjunction with a method of noninterferometric quantitative phase imaging for direct imaging of exoplanets is will present. The light source is passing through tiny holes drilled on the thin metal plate is used as the simulated stellar and its companions. Those diffracted light at the edge of the holes bears a similarity to the light from the bright stellar. Those images are evaginated about the optical axis after the maximum focal length of the first axicon lens. Then the evaginated images of have cut off using the motorized iris which means the suppressed the central stellar light preferentially. Various length between the holes which represent the angular distance are examined. The laboratory experimental results are shown that the axicon-lens coronagraph has feature of ability to achieve the smaller IWA than l/D and high-contrast direct imaging. The laboratory based axicon-lens coronagraph imaging support the symbolic computation results which has potential in direct imaging for finding exoplanet and various astrophysical activities. The setup of the coronagraph is simple to build and is durable to operate. Moreover it can be transported the planets images to a broadband spectrometric instrument that able to investigate the constituent of the planetary system.

  13. Dynamic metasurface lens based on MEMS technology

    Science.gov (United States)

    Roy, Tapashree; Zhang, Shuyan; Jung, Il Woong; Troccoli, Mariano; Capasso, Federico; Lopez, Daniel

    2018-02-01

    In the recent years, metasurfaces, being flat and lightweight, have been designed to replace bulky optical components with various functions. We demonstrate a monolithic Micro-Electro-Mechanical System (MEMS) integrated with a metasurface-based flat lens that focuses light in the mid-infrared spectrum. A two-dimensional scanning MEMS platform controls the angle of the lens along two orthogonal axes by ±9°, thus enabling dynamic beam steering. The device could be used to compensate for off-axis incident light and thus correct for aberrations such as coma. We show that for low angular displacements, the integrated lens-on-MEMS system does not affect the mechanical performance of the MEMS actuators and preserves the focused beam profile as well as the measured full width at half maximum. We envision a new class of flat optical devices with active control provided by the combination of metasurfaces and MEMS for a wide range of applications, such as miniaturized MEMS-based microscope systems, LIDAR scanners, and projection systems.

  14. Sterility and the disinfection potential of Indian contact lens solutions

    Directory of Open Access Journals (Sweden)

    Gopinathan Usha

    1994-01-01

    Full Text Available Ocular infection associated with microbial contamination of contact lens care products is a major problem in contact lens wearers. The sterility and the antimicrobial activity of contact lens care systems reflect their suitability for disinfection of contact lenses. These factors remain to be evaluated for the various newer contact lens care products manufactured in India. In this study, 35 bottles of contact lens solutions marketed by different manufacturing units in India were tested for sterility. Seven solutions were tested for antimicrobial effectiveness employing the D value method of analysis. The D value is defined as the time required to reduce a population of organisms by 90% (one log unit. A standard inoculum of the ocular isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Aspergillus fumigatus, Fusarium solani, and Acanthamoeba castellanii were used as challenge organisms. Bacterial contamination was detected in 20 (57.1% solution bottles and none yielded fungus or Acanthamoeba. Pseudomonas species were the most commonly encountered contaminant (11/20; 55%. Only sterile solutions were analyzed for antimicrobial activity. D values ranging between 12 and 20 minutes were demonstrated by six of the seven solutions against bacterial challenge. Good antifungal activity was noticed in five solutions against Fusarium solani though results varied with Aspergillus flavus and Candida albicans. All solutions were adequately effective against Acanthamoeba.

  15. 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.

  16. [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.

  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. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. 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

  8. New Resources on Youth Reproductive Health and HIV Prevention, 2002-2004. YouthLens on Reproductive Health and HIV/AIDS. Number 14

    Science.gov (United States)

    Finger, William, Comp.; Tipton, Margaret, Comp.

    2005-01-01

    As a sequel to YouthLens No. 1, New Resources Available on Youth Reproductive Health and HIV Prevention (July 2002), this YouthLens summarizes major reports and resources that have appeared since July 2002. The resources are organized by overview reports, reproductive health resources, and HIV/AIDS resources. [YouthLens is an activity of YouthNet,…

  9. 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.

  10. Hyperchromatic lens for recording time-resolved phenomena

    Science.gov (United States)

    Frayer, Daniel K.

    2017-07-11

    A method and apparatus for the capture of a high number of quasi-continuous effective frames of 2-D data from an event at very short time scales (from less than 10.sup.-12 to more than 10.sup.-8 seconds) is disclosed which allows for short recording windows and effective number of frames. Active illumination, from a chirped laser pulse directed to the event creates a reflection where wavelength is dependent upon time and spatial position is utilized to encode temporal phenomena onto wavelength. A hyperchromatic lens system receives the reflection and maps wavelength onto axial position. An image capture device, such as holography or plenoptic imaging device, captures the resultant focal stack from the hyperchromatic lens system in both spatial (imaging) and longitudinal (temporal) axes. The hyperchromatic lens system incorporates a combination of diffractive and refractive components to maximally separate focal position as a function of wavelength.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. Definition, aims, and implementation of GA(2) LEN Urticaria Centers of Reference and Excellence

    DEFF Research Database (Denmark)

    Maurer, M; Metz, M; Bindslev-Jensen, C

    2016-01-01

    BACKGROUND: GA²LEN, the Global Allergy and Asthma European Network, has recently launched a program for the development, interaction, and accreditation of centers of reference and excellence in special areas of allergy embedded in its overall quality management of allergy centers of excellence...... such as urticaria. AIMS: Here, we describe the aims, the requirements and deliverables, the application process, and the audit and accreditation protocol for GA²LEN UCAREs. RESULTS: The main aims of GA²LEN UCAREs are to provide excellence in urticaria management, to increase the knowledge of urticaria by research...... and education, and to promote the awareness of urticaria by advocacy activities. To become a certified GA²LEN UCARE, urticaria centers have to apply and fulfill 32 requirements, defined by specific deliverables that are assessed during an audit visit. DISCUSSION AND CONCLUSION: The GA²LEN UCARE program...

  16. 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.

  17. 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.

  18. "Journalism, Poetry, Stand-Up Comedy, and Academic Writing: Mapping the Interplay of Curricular and Extracurricular Literate Activities": Re-Visiting a Theoretical Lens Five Years Later

    Science.gov (United States)

    Roozen, Kevin

    2014-01-01

    Published in a 2008 issue of "Journal of Basic Writing" ("JBW"), "Journalism, Poetry, Stand-Up Comedy, and Academic Writing: Mapping the Interplay of Curricular and Extracurricular Literate Activities" was Kevin Roozen's first single-authored publication. Drawn from data collected for the first case study from…

  19. The effect of near-UV light on Na-K-ATPase of the rat lens

    International Nuclear Information System (INIS)

    Torriglia, A.; Zigman, S.

    1988-01-01

    The influence of in vitro near-UV radiation exposure on the physical state of the rat lens and on its membrane-bound Na-K-ATPase activity was investigated. Lens swelling was correlated to the appearance of opacities and the inactivation of the enzyme. The results show a significant decrease in the Na-K-ATPase activity which may be an early change leading to osmotic type cataracts. The dose-effect curves obtained for cortical and epithelial enzymes were different. Since the data do not follow a mono-exponential function, the existence of two forms of Na-K-ATPase in the lens is discussed. (author)

  20. Effect of near-UV light on Na-K-ATPase of the rat lens

    Energy Technology Data Exchange (ETDEWEB)

    Torriglia, A.; Zigman, S.

    1988-06-01

    The influence of in vitro near-UV radiation exposure on the physical state of the rat lens and on its membrane-bound Na-K-ATPase activity was investigated. Lens swelling was correlated to the appearance of opacities and the inactivation of the enzyme. The results show a significant decrease in the Na-K-ATPase activity which may be an early change leading to osmotic type cataracts. The dose-effect curves obtained for cortical and epithelial enzymes were different. Since the data do not follow a mono-exponential function, the existence of two forms of Na-K-ATPase in the lens is discussed.

  1. Activated, but Stuck”: Applying a Critical Occupational Lens to Examine the Negotiation of Long-Term Unemployment in Contemporary Socio-Political Contexts

    Directory of Open Access Journals (Sweden)

    Debbie Laliberte Rudman

    2016-09-01

    Full Text Available Background: Solutions for the problem of long-term unemployment are increasingly shaped by neoliberally-informed logics of activation and austerity. Because the implications of these governing frameworks for everyday life are not well understood, this pilot study applied a critical occupational science perspective to understand how long-term unemployment is negotiated within contemporary North American socio-political contexts. This perspective highlights the implications of policy and employment service re-configurations for the range of activities that constitute everyday life. Methods: Using a collaborative ethnographic community-engaged research approach, we recruited eight people in Canada and the United States who self-identified as experiencing long-term unemployment. We analyzed interviews and observation notes concerning four participants in each context using open coding, critical discourse analysis, and situational analysis. Results: This pilot study revealed a key contradiction in participants’ lives: being “activated, but stuck”. This contradiction resulted from the tension between individualizing, homogenizing frames of unemployment and complex, socio-politically shaped lived experiences. Analysis of this tension revealed how participants saw themselves “doing all the right things” to become re-employed, yet still remained stuck across occupational arenas. Conclusion: This pilot study illustrates the importance of understanding how socio-political solutions to long-term unemployment impact daily life and occupational engagement beyond the realm of job seeking and job acquisition.

  2. 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.

  3. 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.

  4. 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.

  5. TU-E-201-02: Eye Lens Dosimetry From CT Perfusion Studies

    International Nuclear Information System (INIS)

    Zhang, D.

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  6. TU-E-201-02: Eye Lens Dosimetry From CT Perfusion Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D. [Toshiba America Medical Systems (United States)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  7. TU-E-201-00: Eye Lens Dosimetry for Patients and Staff

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  8. 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.

  9. Protective Effects of Acetylation on the Pathological Reactions of the Lens Crystallins with Homocysteine Thiolactone.

    Directory of Open Access Journals (Sweden)

    Zeinab Moafian

    Full Text Available Various post-translational lens crystallins modifications result in structural and functional insults, contributing to the development of lens opacity and cataract disorders. Lens crystallins are potential targets of homocysteinylation, particularly under hyperhomocysteinemia which has been indicated in various eye diseases. Since both homocysteinylation and acetylation primarily occur on protein free amino groups, we applied different spectroscopic methods and gel mobility shift analysis to examine the possible preventive role of acetylation against homocysteinylation. Lens crystallins were extensively acetylated in the presence of acetic anhydride and then subjected to homocysteinylation in the presence of homocysteine thiolactone (HCTL. Extensive acetylation of the lens crystallins results in partial structural alteration and enhancement of their stability, as well as improvement of α-crystallin chaperone-like activity. In addition, acetylation partially prevents HCTL-induced structural alteration and aggregation of lens crystallins. Also, acetylation protects against HCTL-induced loss of α-crystallin chaperone activity. Additionally, subsequent acetylation and homocysteinylation cause significant proteolytic degradation of crystallins. Therefore, further experimentation is required in order to judge effectively the preventative role of acetylation on the structural and functional insults induced by homocysteinylation of lens crystallins.

  10. 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

  11. [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.

  12. Primary anterior chamber intraocular lens for the treatment of severe crystalline lens subluxation.

    Science.gov (United States)

    Hoffman, Richard S; Fine, I Howard; Packer, Mark

    2009-10-01

    Subluxated cataractous and clear lenses are commonly treated by limbal or pars plana lensectomy followed by primary or secondary intraocular lens (IOL) implantation. Adjunctive capsular prosthetic devices have facilitated lens removal and IOL centration in these challenging cases but have also added complexity and potential complications to the procedure. Although crystalline lens extraction may be required to clear the visual axis in mild to moderate lens subluxations, we propose insertion of a primary anterior chamber IOL without lens extraction in severe subluxations when the eye is optically aphakic or can be made functionally aphakic following neodymium:YAG laser zonulysis. Two cases demonstrating this approach are presented.

  13. Protection of the eye lens

    International Nuclear Information System (INIS)

    2015-01-01

    The limit of radiation exposure for eye lens is going to decrease dramatically from 150 to 20 mSv as a transposition into the French law of a CIPR (International Commission for Radiation Protection) directive. Sanitary studies have shown that radiologists are more likely by a factor of 3.8 to get eye lens opacities than the rest of the population. The wearing of protective glasses is recommended and in order to get a better monitoring of the radiation dose new dosimeters have been designed, they can be worn on the glass frame of directly stuck on the skin near the eyes. A study has shown that veterinary surgeons that are accustomed to stay near animals to keep them quiet during radiological exams are prone to receive high doses as well as physicians that use hypnosis to decrease the level of anxiety of their patients during radiological exams. Radiation exposure of radiologists can be mitigated through: the use of protective shields and equipment and the optimization of the dose delivered to the patient. (A.C.)

  14. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    Kritchman, E.M.

    1979-01-01

    A new linear convex Fresnel lens with its groove side down is described. The design philosophy is similar to the highly concentrating two focal Fresnel lens but including a correction for chromatic aberration. A solar concentration ratio as high as 80 is achieved. For wide acceptance angles the concentration nears the theoretical maximum. (author)

  15. Modified suturing contact lens for penetrating keratoplasty.

    Science.gov (United States)

    Kramer, S G; Stewart, H L

    1978-11-01

    The authors have previously described a suturing contact lens that protects the corneal endothelium by aiding in the maintenance of the anterior chamber during penetrating keratoplasty. This report describes structural modifications of the suturing contact lens, which improve its stability and effectiveness. An additional configuration for use in corneal lacerations is presented.

  16. Charged black lens in de Sitter space

    Science.gov (United States)

    Tomizawa, Shinya

    2018-02-01

    We obtain a charged black lens solution in the five-dimensional Einstein-Maxwell-Chern-Simons theory with a positive cosmological constant. It is shown that the solution obtained here describes the formation of a black hole with the spatial cross section of a sphere from that of the lens space of L (n ,1 ) in five-dimensional de Sitter space.

  17. Design method of freeform light distribution lens for LED automotive headlamp based on DMD

    Science.gov (United States)

    Ma, Jianshe; Huang, Jianwei; Su, Ping; Cui, Yao

    2018-01-01

    We propose a new method to design freeform light distribution lens for light-emitting diode (LED) automotive headlamp based on digital micro mirror device (DMD). With the Parallel optical path architecture, the exit pupil of the illuminating system is set in infinity. Thus the principal incident rays of micro lens in DMD is parallel. DMD is made of high speed digital optical reflection array, the function of distribution lens is to distribute the emergent parallel rays from DMD and get a lighting pattern that fully comply with the national regulation GB 25991-2010.We use DLP 4500 to design the light distribution lens, mesh the target plane regulated by the national regulation GB 25991-2010 and correlate the mesh grids with the active mirror array of DLP4500. With the mapping relations and the refraction law, we can build the mathematics model and get the parameters of freeform light distribution lens. Then we import its parameter into the three-dimensional (3D) software CATIA to construct its 3D model. The ray tracing results using Tracepro demonstrate that the Illumination value of target plane is easily adjustable and fully comply with the requirement of the national regulation GB 25991-2010 by adjusting the exit brightness value of DMD. The theoretical optical efficiencies of the light distribution lens designed using this method could be up to 92% without any other auxiliary lens.

  18. Contact Lens Use in the Civil Airman Population

    National Research Council Canada - National Science Library

    Nakagawara, Van

    2002-01-01

    ...) aeromedical certificate. Although contact lens technology has advanced dramatically in recent years, the aviation environment may still have adverse effects on contact lens performance in some flight situations...

  19. Corrected electrostatic lens systems for ion beams

    International Nuclear Information System (INIS)

    Dalgish, R.L.

    1981-01-01

    Recent work in our laboratory has introduced a new class of electrostatic focus forming element for beams, the ELCO lens. It compares favourably with the electrostatic and magnetic quadrupole elements conventionally used for microbeam formation. The ELCO lens does however have disadvantages associated with apertures and alignment. We have continued with the development of ion beam lenses and have evolved a further class of lens element which eliminates aperture and alignment problems. This new element can be combined like optical lenses into an aberration corrected system. Experimental measurement on the basic lens element has confirmed mathematical analysis of ion trajectories through the element. This mathematical analysis predicts that the basic element can be combined into a corrected lens system for, either: (1) high resolution microprobe formation with intrinsic rastering ability, the spot size limited only by the beam properties; or (2) high quality image formation with large magnification/demagnification ratio and wide angular aperture. (orig.)

  20. Overlapped illusion optics: a perfect lens brings a brighter feature

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yadong; Gao Lei; Chen Huanyang [School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006 (China); Du Shengwang, E-mail: kenyon@ust.hk [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2011-02-15

    In this paper, we show that a perfect lens can be employed to make multiple objects appear like only one object in the far field, leading to a new concept in illusion optics. Numerical simulations have been performed to verify the functionalities for both passive and active objects. The conceptual device can be utilized to enhance the illumination brightness for both incoherent and coherent systems.

  1. Overlapped illusion optics: a perfect lens brings a brighter feature

    International Nuclear Information System (INIS)

    Xu Yadong; Gao Lei; Chen Huanyang; Du Shengwang

    2011-01-01

    In this paper, we show that a perfect lens can be employed to make multiple objects appear like only one object in the far field, leading to a new concept in illusion optics. Numerical simulations have been performed to verify the functionalities for both passive and active objects. The conceptual device can be utilized to enhance the illumination brightness for both incoherent and coherent systems.

  2. Investigation of lens morphology and mechanical characteristics of lens capsule and lens nucleus in patients with agerelated and diabetic cataract

    Directory of Open Access Journals (Sweden)

    A. S. Tishkova

    2014-07-01

    Full Text Available Purpose: To investigate the influence of carbohydrate metabolism on the structure and mechanical properties of the lens capsule and nucleus.Methods: Human lens pathology was studied in different forms of cataract. 220 patients with a cataract (220 eyes were included in this study. Morphological, immunohystological and immunocytochemical investigations of lens substance (antibodies to a- (a-А and a-В, b-, g- crystallines, spectroscopic analyses of smears and morphometric analyses of slices, investigation of lens morphology and mechanical caracteristics of lens capsule and lens nucleus were performed.Results: The capsule of the lens in patients with senile cataract contains more Na+, Cl-. The capsule of the lens in patients with senile cataract contains more Ca2+, O. Mechanical strength of the capsule in the case of diabetes mellitus was lower comparatively with senile cataract in the same age groups. More significant expression of a-В and b-crystallines was found in patients with diabetes mellitus comparatively with patients with age-related cataract. Morphological features were founded in patients with cortical and nuclear forms of senile cataract and the diabetic cataract.Conclusion: During surgery (ultrasonic microcoaxial phacoemulsification the equivalent of ultrasound was recorded. Lower density of the lens nucleus of patients with diabetes mellitus made it possible to use lower energy parameters. Using the torsion ultrasound in those cases allowed us to decrease the influence of ultrasound on eye tissues and reduce the time of achieving the maximum BCVA in the postsurgical period.

  3. Investigation of lens morphology and mechanical characteristics of lens capsule and lens nucleus in patients with agerelated and diabetic cataract

    Directory of Open Access Journals (Sweden)

    A. S. Tishkova

    2013-01-01

    Full Text Available Purpose: To investigate the influence of carbohydrate metabolism on the structure and mechanical properties of the lens capsule and nucleus.Methods: Human lens pathology was studied in different forms of cataract. 220 patients with a cataract (220 eyes were included in this study. Morphological, immunohystological and immunocytochemical investigations of lens substance (antibodies to a- (a-А and a-В, b-, g- crystallines, spectroscopic analyses of smears and morphometric analyses of slices, investigation of lens morphology and mechanical caracteristics of lens capsule and lens nucleus were performed.Results: The capsule of the lens in patients with senile cataract contains more Na+, Cl-. The capsule of the lens in patients with senile cataract contains more Ca2+, O. Mechanical strength of the capsule in the case of diabetes mellitus was lower comparatively with senile cataract in the same age groups. More significant expression of a-В and b-crystallines was found in patients with diabetes mellitus comparatively with patients with age-related cataract. Morphological features were founded in patients with cortical and nuclear forms of senile cataract and the diabetic cataract.Conclusion: During surgery (ultrasonic microcoaxial phacoemulsification the equivalent of ultrasound was recorded. Lower density of the lens nucleus of patients with diabetes mellitus made it possible to use lower energy parameters. Using the torsion ultrasound in those cases allowed us to decrease the influence of ultrasound on eye tissues and reduce the time of achieving the maximum BCVA in the postsurgical period.

  4. Cuba Through A New Lens

    Directory of Open Access Journals (Sweden)

    Jean Stubbs

    2008-12-01

    Full Text Available [First paragraph] The Origins of the Cuban Revolution Reconsidered. Samuel Farber. Chapel Hill: University of North Carolina Press, 2006. x + 212 pp. (Paper US$ 19.95 Cuba: A New History. Ric hard Gott . New Haven: Yale University Press, 2005. xii + 384 pp. (Paper US$ 17.00 Havana: The Making of Cuban Culture. Antoni Kapcia. Oxford: Berg Publishers, 2005. xx + 236 pp. (Paper US$ 24.95 Richard Gott, Antoni Kapcia, and Samuel Farber each approach Cuba through a new lens. Gott does so by providing a broad-sweep history of Cuba, which is epic in scope, attaches importance to social as much as political and economic history, and blends scholarship with flair. Kapcia homes in on Havana as the locus for Cuban culture, whereby cultural history becomes the trope for exploring not only the city but also Cuban national identity. Farber revisits his own and others’ interpretations of the origins of the Cuban Revolution.

  5. 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.)

  6. Microbial contamination of contact lens storage cases and domestic tap water of contact lens wearers.

    Science.gov (United States)

    Üstüntürk, Miray; Zeybek, Zuhal

    2012-11-01

    Contact lenses have been widely used as an alternative to spectacles both in developed and developing countries. However, under certain circumstances, adverse responses can occur during contact lens wear and several microorganisms--including bacteria, fungi, and free living amoebae--can cause several eye infections in wearers. Extended wear of contact lenses is the major risk factor of eye infections such as microbial keratitis, besides contaminated contact lens storage case, contaminated lens care solutions, and inaccurate contact lens handling. In this study, we collected contact lens storage case and domestic tap water samples from 50 asymptomatic contact lens wearers. We determined that total aerobic mesophilic bacteria were isolated in 45 (90 %), Gram negative rod bacteria were isolated in 20 (40 %), Pseudomonas spp. were isolated in 2 (4 %) and fungi were isolated in 18 (36 %) out of 50 contact lens storage cases. Free living amoebae were not detected in investigated contact lens storage cases. At the same time, out of 50, total aerobic mesophilic bacteria were isolated in 34 (68 %), fungi were isolated in 15 (30 %) and free living amoebae were isolated in 15 (30 %) domestic tap water samples. No Gram-negative rod bacteria and Pseudomonas spp. were detected in investigated water samples. Two contact lens case samples and two tap water samples were excluded from the analysis for Pseudomonas spp. for technical reasons. According to our findings, inadequate contact lens maintenance during lens wear may result in the contamination of contact lens storage cases. This situation can lead to severe eye infections in contact lens wearers over time.

  7. Hard contact lens-induced metabolic changes in rabbit corneas.

    Science.gov (United States)

    Tsubota, K; Kenyon, K R; Cheng, H M

    1989-11-01

    The biochemistry of contact lens-cornea interaction is not well understood, although previous studies have suggested that corneal metabolic changes may be the underlying factor in morphological alterations. Using a rabbit model, this interaction has been examined with 31P nuclear magnetic resonance (NMR) spectroscopy, which detects signals principally from the epithelium. The examination was supplemented with electron microscopy and histochemistry. Polymethylmethacrylate lenses caused reversible changes, including activation of anaerobic glycolysis and disturbance of membrane metabolite levels. These changes were far more severe than those occurring during prolonged eye closure. There appears to be an association between cellular deterioration and loss of membrane metabolites. On the other hand, oxygen-permeable silicone lenses allowed maintenance of nearly normal metabolic patterns. These results show multifaceted corneal response to hard contact lens wear.

  8. Contact lens compliance among a group of young, university-based lens users in South India.

    Science.gov (United States)

    Noushad, Babu; Saoji, Yeshwant; Bhakat, Premjit; Thomas, Jyothi

    2012-01-01

    To investigate the rate of compliance with the soft contact lens care and maintenance procedures with a focus on contact lens wearing habits, cleaning and disinfecting procedures, and maintenance of lens care accessories in a group of young, university-based contact lens wearers Two hundred and sixteen young soft contact lens wearers with an age range of 18-22 years were selected conveniently from the student population of Manipal University, Manipal, India. After receiving informed consent from the participants, their level of compliance with contact lenses was assessed using a questionnaire. The mean (±SD) age of the participants was 21.86±2.35 years. Out of 216 subjects, only 34% of the lens users were identified to be compliant with the least level of compliance observed in the maintenance of lens care accessories. Conventional users showed significantly (p=0.001) better level of compliance compared to disposable wearers and so did the users who acquired their lenses from clinicians (p=0.001) compared to over-the-counter lens receipt. The gender (p=0.496) and years of experience in contact lens use (p=0.142) did not show any statistically significant difference in the level of compliance. This study demonstrated that non-compliance with lens care procedures among a group of young, university-based soft contact lens wearers is common. The results indicated that all subjects had some degree of non-compliance and the least level of compliance observed in the care of lens accessories.

  9. Tear film physiology and contact lens wear. II. Contact lens-tear film interaction.

    Science.gov (United States)

    Holly, F J

    1981-04-01

    The successful fitting of contact lenses requires the practitioner to take into account many properties of the specific lens type used but the practitioner must also understand patient factors including tear properties, use of appropriate solutions, procedures for lens cleaning, and efficiency of blinking. Selection of appropriate patients, selection of lens type, proper fitting, good maintenance, and training and monitoring of patients increase the probability of achieving success.

  10. Placement of a crystalline lens and intraocular lens: Retinal image quality.

    Science.gov (United States)

    Siedlecki, Damian; Nowak, Jerzy; Zajac, Marek

    2006-01-01

    The influence of changes of both crystalline lens and intraocular lens (IOL) misalignment on the retinal image quality was investigated. The optical model of the eye used in investigations was the Liou-Brennan model, which is commonly considered as one of the most anatomically accurate. The original crystalline lens from this model was replaced with an IOL, made of rigid polymethylmethacrylate, in a way that recommend obligatory procedures. The modifications that were made both for crystalline lens and IOL were the longitudinal, the transversal, and the angular displacement.

  11. Restoring lens capsule integrity enhances lens regeneration in New Zealand albino rabbits and cats.

    Science.gov (United States)

    Gwon, A; Gruber, L J; Mantras, C

    1993-11-01

    In studies conducted by numerous investigators for 150 years, lenses regenerated following endocapsular lens extraction in New Zealand albino rabbits have been irregular in shape, appearing primarily doughnut-shaped as a result of lack of lens growth at the site of the anterior capsulotomy and its adhesion to the posterior capsule. In the present study, we restored the lens capsule integrity by inserting a collagen patch at the time of surgery to seal the anterior capsulotomy and to improve the shape and structure of the regenerated lenses. We then filled the capsule bag with air to prevent adhesions between the anterior and posterior capsule and maintain capsule tautness and shape. Lens regeneration was first noted as early as one to two weeks. Regenerated lens filled approximately 50% of the capsule bag at two weeks and 100% by five weeks. Subsequent growth was in the anterior-posterior direction and measured by A-scan biometry. Lens thickness increased by 0.3 mm per month. The regenerated lenses were spherical with normal cortical structure and a nuclear opacity. In conclusion, restoration of lens capsular integrity with a collagen patch following endocapsular lens extraction enhanced the shape, structure, and growth rate of the regenerated lenses. In addition, lens regeneration was shown to occur in two cats.

  12. Development of Fresnel lens for improvement of rear visibility; Shikai kojo Fresnel lens no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, K.; Sanada, C.; Tsukino, M. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    Fresnel lenses have been widely used to increase the visual field around vehicles for drivers. However, internal reflection in these lenses has been an obstacle in producing dear images. This internal glow is generated by incident light from an unexpected direction reflecting on the non-lens surface or radiating from the non-lens surface of the Fresnel lens. The cause of internal glow has been made dear combining louver film with the lens. The newly developed technology removes obstacles in producing dear images by reducing internal glow. 7 figs.

  13. Night Vision Goggles Objectives Lens Focusing Methodology

    National Research Council Canada - National Science Library

    Pinkus, Alan; Task, H. L

    2000-01-01

    ...: interpupillary distance, tilt, eye relief, height, eyepiece and objective lens focus. Currently, aircrew use a Hoffman 20/20 test unit to pre-focus their NVG objective lenses at optical infinity before boarding their aircraft...

  14. 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

  15. Contractual considerations in contact lens practice.

    Science.gov (United States)

    Classé, J G

    1986-03-01

    The use of forms in contact lens practice can save time, promote patient education, and reduce the opportunity for legal or economic disputes. The most commonly employed forms are those for contact lens fitting agreements, instructions for care and maintenance of lenses, prepaid service agreements, clinical investigations of investigatory lenses or solutions, and for extended wear patients. Sample forms are utilized for purposes of illustration.

  16. Evolution and the Calcite Eye Lens

    OpenAIRE

    Williams, Vernon L.

    2013-01-01

    Calcite is a uniaxial, birefringent crystal, which in its optically transparent form, has been used for animal eye lenses, the trilobite being one such animal. Because of the calcite birefringence there is a difficulty in using calcite as a lens. When the propagation direction of incoming light is not exactly on the c-axis, the mages blur. In this paper, calcite blurring is evaluated, and the non-blurring by a crystallin eye lens is compared to a calcite one.

  17. Acute lens-induced glaucomas: A review

    Directory of Open Access Journals (Sweden)

    Syed Shoeb Ahmad

    2017-02-01

    Full Text Available Lens-induced factors are important and common mechanisms causing acute elevation of intraocular pressure. While in most cases, the diagnosis and management are straight-forward, in others it is difficult and can lead to improper procedures, complications and poor visual outcomes. This review was done with the aim of studying the various types of lens-induced glaucomas, classifying them in an easy way to understand manner, their clinical features, current management and future possibilities.

  18. Acoustic lens for capacitive micromachined ultrasonic transducers

    Science.gov (United States)

    Chang, Chienliu; Firouzi, Kamyar; Park, Kwan Kyu; Sarioglu, Ali Fatih; Nikoozadeh, Amin; Yoon, Hyo-Seon; Vaithilingam, Srikant; Carver, Thomas; Khuri-Yakub, Butrus T.

    2014-08-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing.

  19. Acoustic lens for capacitive micromachined ultrasonic transducers

    International Nuclear Information System (INIS)

    Chang, Chienliu; Firouzi, Kamyar; Sarioglu, Ali Fatih; Nikoozadeh, Amin; Yoon, Hyo-Seon; Vaithilingam, Srikant; Carver, Thomas; Khuri-Yakub, Butrus T; Kyu Park, Kwan

    2014-01-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing. (paper)

  20. Comparison of lens oxidative damage induced by vitrectomy and/or hyperoxia in rabbits

    Directory of Open Access Journals (Sweden)

    Hong Yan

    2017-02-01

    Full Text Available AIM: To compare of lens oxidative damage induced by vitrectomy and/or hyperoxia in rabbit. METHODS: Sixteen New Zealand rabbits (2.4-2.5 kg were randomly divided into two groups (Group A, n=12; Group B, n=4. In Group A, the right eyes were treated with vitrectomy and systemic hyperoxia (oxygen concentration: 80%-85%, 1 ATA, 4h/d (Group A-right, and the left eyes were treated with hyperoxia without vitrectomy surgery (Group A-left. Four rabbits in group B (eight eyes were untreated as the controls. Lens transparency was monitored with a slit lamp and recorded before and after vitrectomy. After hyperoxic treatment for 6mo, the eyeballs were removed and the lens cortices (containing the capsules and nuclei were separated for further morphological and biochemical evaluation. RESULTS: Six months after treatments, there were no significant morphological changes in the lenses in any experimental group when observed with a slit lamp. However, the levels of water-soluble proteins and ascorbate, and the activities of catalase and Na+-K+-ATPase were significantly reduced, whereas the levels of malondialdehyde and transforming growth factor β2 (TGF-β2 were significantly elevated, in both the cortices and nuclei of eyes treated with vitrectomy and hyperoxia. The increase in protein-glutathione mixed disulfides and the reduction in water-soluble proteins were more obvious in the lens nuclei. The levels of ascorbate in the vitreous fluid were also reduced after vitrectomy, whereas TGF-β2 increased after vitrectomy and hyperoxia. Systemic hyperoxia exposure increased these effects. CONCLUSION: Removal of the intact vitreous gel with vitrectomy and exposing the lens to increased oxygen from the retina induce lens oxidation and aggregation. Thus, an intact vitreous gel structure may protect the lens from oxidative insult and maintain lens transparency.

  1. The incorporation of 2-[14C]glycine into porcine lens protein

    International Nuclear Information System (INIS)

    Lee, Y.B.; Kauffman, R.G.; DeVenecia, G.

    1977-01-01

    A series of experiments was conducted to estimate the apparent turnover rate of lens soluble protein, the incorporation rate of 2-[ 14 C]glycine into various soluble protein components and the effect of nutritional stress on the disappearance of radioactivity with time. Evidence is presented that there are two fractions of soluble lens protein with different turnover rates: one is a fast turnover fraction with a half-life of 20.8 hr and the other is a metabolically inert fraction with an infinitely long half-life. It is postulated that the fast turnover fraction is present in the newly-formed younger fibers in the periphery, whereas the inert fraction is in the old lens fibers of the cortex and nucleus. Sephadex G-200 column chromatography was used to separate the soluble lens protein into four components: A, B, C and D in the order of elution. The changes in specific activities of the four components with the time course after injection were followed. Prolonged starvation did not affect the disappearance of carbon incorporated into lens protein with the time course after injection, suggesting normal synthesis and degradation of lens protein without regard to dietary stress. (author)

  2. Estimation of lens dose of radioactive isotopes using ED3

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ha Jin; Ju, Yong Jin; Jang, Han; Kang, Kyeong Won; Chung, Woon Kwan [Chosun University, Gwangju (Korea, Republic of); Dong, Kyung Rae [Gwangju Health University, Gwangju (Korea, Republic of); Choi, Eun Jin; Kwak, Jong Gil [Dongshin University Graduate School, Naju (Korea, Republic of); Ryu, Jae Kwang [Asan Medical Center, Seoul (Korea, Republic of)

    2017-03-15

    It is suggested that the dose limit recommended in the Enforcement Decree of Korea's Nuclear Safety Act should not exceed 150 mSv per year for radiation workers. Recently, however, ICRP 118 report has suggested that the threshold dose of the lens should be reduced to 0.2⁓0.5 Gy and the mean dose should not exceed 50 mSv per year for an average of 20 mSv over 5 years. Based on these contents, '1'2'3I, '9'9mTc, and '1'8F-FDG, which are radioisotope drugs that are used directly by radiation workers in the nuclear medicine department in Korea are expected to receive a large dose of radiation in the lens in distribution and injection jobs to administer them to patients. The ED3 Active Extremity Dosimeter was used to measure the dose of the lens in the nuclear medicine and radiation workers and how much of the dose was received per 1 mCi.

  3. Sharing of secondary electrons by in-lens and out-lens detector in low-voltage scanning electron microscope equipped with immersion lens.

    Science.gov (United States)

    Kumagai, Kazuhiro; Sekiguchi, Takashi

    2009-03-01

    To understand secondary electron (SE) image formation with in-lens and out-lens detector in low-voltage scanning electron microscopy (LV-SEM), we have evaluated SE signals of an in-lens and an out-lens detector in LV-SEM. From the energy distribution spectra of SEs with various boosting voltages of the immersion lens system, we revealed that the electrostatic field of the immersion lens mainly collects electrons with energy lower than 40eV, acting as a low-pass filter. This effect is also observed as a contrast change in LV-SEM images taken by in-lens and out-lens detectors.

  4. Acanthamoeba keratitis and contact lens wear.

    Science.gov (United States)

    Lindsay, Richard G; Watters, Grant; Johnson, Richard; Ormonde, Susan E; Snibson, Grant R

    2007-09-01

    Acanthamoeba keratitis is a rare but serious complication of contact lens wear that may cause severe visual loss. The clinical picture is usually characterised by severe pain, sometimes disproportionate to the signs, with an early superficial keratitis that is often misdiagnosed as herpes simplex virus (HSV) keratitis. Advanced stages of the infection are usually characterised by central corneal epithelial loss and marked stromal opacification with subsequent loss of vision. In this paper, six cases of contact lens-related Acanthamoeba keratitis that occurred in Australia and New Zealand over a three-year period are described. Three of the patients were disposable soft lens wearers, two were hybrid lens wearers and one was a rigid gas permeable lens wearer. For all six cases, the risk factors for Acanthamoeba keratitis were contact lens wear with inappropriate or ineffective lens maintenance and exposure of the contact lenses to tap or other sources of water. All six patients responded well to medical therapy that involved topical use of appropriate therapeutic agents, most commonly polyhexamethylene biguanide and propamidine isethionate, although two of the patients also subsequently underwent deep lamellar keratoplasty due to residual corneal surface irregularity and stromal scarring. Despite the significant advances that have been made in the medical therapy of Acanthamoeba keratitis over the past 10 years, prevention remains the best treatment and patients who wear contact lenses must be thoroughly educated about the proper use and care of the lenses. In particular, exposure of the contact lenses to tap water or other sources of water should be avoided.

  5. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    International Nuclear Information System (INIS)

    Konvalina, I.; Muellerova, I.

    2011-01-01

    The cathode lens is an electron optical element in an emission electron microscope accelerating electrons from the sample, which serves as a source for a beam of electrons. Special application consists in using the cathode lens first for retardation of an illuminating electron beam and then for acceleration of reflected as well as secondary electrons, made in the directly imaging low energy electron microscope or in its scanning version discussed here. In order to form a real image, the cathode lens has to be combined with a focusing magnetic lens or a focusing immersion-magnetic lens, as used for objective lenses of some commercial scanning electron microscopes. These two alternatives are compared with regards to their optical properties, in particular with respect to predicted aberration coefficients and the spot size, as well as the optimum angular aperture of the primary beam. The important role of the final aperture size on the image resolution is also presented.

  6. Lens exposure during brain scans using multidetector row CT scanners: methods for estimation of lens dose.

    Science.gov (United States)

    Suzuki, S; Furui, S; Ishitake, T; Abe, T; Machida, H; Takei, R; Ibukuro, K; Watanabe, A; Kidouchi, T; Nakano, Y

    2010-05-01

    Some recent studies on radiation lens injuries have indicated much lower dose thresholds than specified by the current radiation protection guidelines. The purpose of this research was to measure the lens dose during brain CT scans with multidetector row CT and to assess methods for estimating the lens dose. With 8 types of multidetector row CT scanners, both axial and helical scans were obtained for the head part of a human-shaped phantom by using normal clinical settings with the orbitomeatal line as the baseline. We measured the doses on both eyelids by using an RPLGD during whole-brain scans including the orbit with the starting point at the level of the inferior orbital rim. To assess the effect of the starting points on the lens doses, we measured the lens doses by using 2 other starting points for scanning (the orbitomeatal line and the superior orbital rim). The CTDIvols and the lens doses during whole-brain CT including the orbit were 50.9-113.3 mGy and 42.6-103.5 mGy, respectively. The ratios of lens dose to CTDIvol were 80.6%-103.4%. The lens doses decreased as the starting points were set more superiorly. The lens doses during scans from the superior orbital rim were 11.8%-20.9% of the doses during the scans from the inferior orbital rim. CTDIvol can be used to estimate the lens dose during whole-brain CT when the orbit is included in the scanning range.

  7. Indirect evaluation of corneal apoptosis in contact lens wearers by estimation of nitric oxide and antioxidant enzymes in tears

    Directory of Open Access Journals (Sweden)

    R P Bhatia

    2010-01-01

    Full Text Available Background : Contact lens induced trauma to the corneal epithelium results in increased release of inflammatory mediators. The keratocyte apoptosis is directly related to epithelial injury and has been correlated with increased production of nitric oxide. Potent antioxidant enzymes protect cells from oxidative damage by inactivating reactive oxygen species and thus inhibiting apoptosis. This study aims at determination of total nitric oxide and antioxidant enzymes in tears which will be an indirect criteria for assessing apoptosis. Materials and Methods : Nitric oxide and antioxidant enzymes were estimated in tears of 25 soft contact lens wearers and compared with 25 age and sex matched controls. Results : Statistically significant increase of nitric oxide (P< 0.001, superoxide dismutase (P< 0.001 and glutathione peroxidase (P< 0.001 levels was seen in tears of contact lens wearers as compared to controls. There was also statistically significant increase in the levels of antioxidant enzymes, superoxide dismutase (P< 0.05 and glutathione peroxidase (P< 0.01, with increase in the total duration of contact lens wear in years. Conclusions : Increase in the level of nitric oxide and antioxidant enzymes in tears of contact lens wearers suggested that contact lens wear suppresses the process of apoptosis. However, it was also postulated that the increased levels of nitric oxide balances the anti-apoptotic activities of increased levels of antioxidant enzymes by its pro-apoptotic activity leading to protective outcomes in contact lens wearers.

  8. 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

  9. 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.

  10. 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.

  11. Development of Powerhouse Using Fresnel lens

    Directory of Open Access Journals (Sweden)

    Al-Dohani Nawar Saif

    2018-01-01

    Full Text Available Solar energy is an alternative source of renewable energy. Sultanate of Oman government showed initiation on utilization of solar energy for domestic and industrial applications. Fresnel lens is one of the methods to collect maximum energy by gathering heat of the sun in the concentrated form (using solar collectors. Earlier research work discloses that Fresnel lens gave better result in terms of power output and produces lower heat loss as compared to linear –parabolic solar collectors. In this work, development of a proto Fresnel lens power house was made to generate electricity. The focused heat from Fresnel lens was used to heat the molten salt in a heat exchanger to produce the steam. The generated steam was used to rotate the steam engine coupled to a generator. In the current work, a maximum power of 30 W was produced. In addition, comparative study was carried out regarding solar salts and heat exchanger materials to understand the Fresnel powerhouse performance. Overall the present study gave valuable information regarding usage of Fresnel lens for electricity generation in Oman.

  12. Non-compliance in contact lens wear.

    Science.gov (United States)

    Claydon, B E; Efron, N

    1994-10-01

    Non-compliance is emerging as a critical issue in the contact lens field. This problem has been studied at depth in general health care situations and is seen as the responsibility of both practitioner and patient (client) working in a health care partnership. The contact lens practitioner and patient present a specific case for the study of non-compliance in areas such as hygiene, solution use, appointment attendance and wearing times. From 40 to 91% of contact lens patients have been reported as non-complaint in the use of recommended care and maintenance regimens and many of these are confused or ignorant about their behaviour. In order to arrive at a general set of conclusions from the studies published to date, it is important to understand the methodology of each study, it purpose, the definition of non-compliance used and the way the results were analysed and described. This review summarizes the research into non-compliance in the contact lens field to data. A set of general conclusions is drawn and a model for compliance in the context of contact lens practice is proposed.

  13. Spherical aberration in contact lens wear.

    Science.gov (United States)

    Lindskoog Pettersson, A; Jarkö, C; Alvin, A; Unsbo, P; Brautaset, R

    2008-08-01

    The aim of the present studies was to investigate the effect on spherical aberration of different non custom-made contact lenses, both with and without aberration control. A wavefront analyser (Zywave, Bausch & Lomb) was used to measure the aberrations in each subject's right eye uncorrected and with the different contact lenses. The first study evaluated residual spherical aberration with a standard lens (Focus Dailies Disposable, Ciba Vision) and with an aberration controlled contact lens (ACCL) (Definition AC, Optical Connection Inc.). The second study evaluated the residual spherical aberrations with a monthly disposable silicone hydrogel lens with aberration reduction (PureVision, Bausch & Lomb). Uncorrected spherical aberration was positive for all pupil sizes in both studies. In the first study, residual spherical aberration was close to zero with the standard lens for all pupil sizes whereas the ACCL over-corrected spherical aberration. The results of the second study showed that the monthly disposable lens also over-corrected the aberration making it negative. The changes in aberration were statistically significant (plenses. Since the amount of aberration varies individually we suggest that aberrations should be measured with lenses on the eye if the aim is to change spherical aberration in a certain direction.

  14. A lazy way to design infrared lens

    Science.gov (United States)

    Qiu, RongSheng; Wu, JianDong; Chen, LongJiang; Yu, Kun; Pang, HaoJun; Hu, BaiZhen

    2017-08-01

    We designed a compact middle-wave infrared (MWIR) lens with a large focal length ratio (about 1.5:1), used in the 3.7 to 4.8 μm range. The lens is consisted of a compact front group and a re-imaging group. Thanks to the compact front group configuration, it is possible to install a filter wheel mechanism in such a tight space. The total track length of the lens is about 50mm, which includes a 2mm thick protective window and a cold shield of 12mm. The full field of view of the lens is about 3.6°, and F number is less than 1.6, the image circle is about 4.6mm in diameter. The design performance of the lens reaches diffraction limitation, and doesn't change a lot during a temperature range of -40°C +60°C. This essay proposed a stepwise design method of infrared optical system guided by the qualitative approach. The method fully utilize the powerful global optimization ability, with a little effort to write code snippet in optical design software, frees optical engineer from tedious calculation of the original structure.

  15. TESS Lens-Bezel Assembly Modal Testing

    Science.gov (United States)

    Dilworth, Brandon J.; Karlicek, Alexandra

    2017-01-01

    The Transiting Exoplanet Survey Satellite (TESS) program, led by the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT) will be the first-ever spaceborne all-sky transit survey. MIT Lincoln Laboratory is responsible for the cameras, including the lens assemblies, detector assemblies, lens hoods, and camera mounts. TESS is scheduled to be launched in August of 2017 with the primary goal to detect small planets with bright host starts in the solar neighborhood, so that detailed characterizations of the planets and their atmospheres can be performed. The TESS payload consists of four identical cameras and a data handling unit. Each camera consists of a lens assembly with seven optical elements and a detector assembly with four charge-coupled devices (CCDs) including their associated electronics. The optical prescription requires that several of the lenses are in close proximity to a neighboring element. A finite element model (FEM) was developed to estimate the relative deflections between each lens-bezel assembly under launch loads to predict that there are adequate clearances preventing the lenses from making contact. Modal tests using non-contact response measurements were conducted to experimentally estimate the modal parameters of the lens-bezel assembly, and used to validate the initial FEM assumptions. Key Words Non-contact measurements, modal analysis, model validation

  16. Acanthamoeba, bacterial, and fungal contamination of contact lens storage cases.

    Science.gov (United States)

    Gray, T B; Cursons, R T; Sherwan, J F; Rose, P R

    1995-01-01

    BACKGROUND--Microbial corneal infection is the most serious complication of contact lens wear. Contact lens cases are a recognised potential source of pathogens associated with corneal ulcers. METHODS--This survey established the incidence of protozoal, bacterial, and fungal contact lens case contamination in 101 asymptomatic daily wear cosmetic contact lens wearers from a domiciliary contact lens practice. RESULTS--Eighty two (81%) contact lens cases were found to be contaminated, with 19 (19%) sterile. Of all contact lens cases, 78 (77%) grew bacteria, 24 (24%) fungi, and 20 (20%) protozoa. Acanthamoeba spp were isolated from eight (8%) contact lens cases. Fifty six (55%) contact lens cases yielded mixed bacterial contamination. This is the first contact lens case survey in which hydrogen peroxide disinfection was the major method of contact lens disinfection (75% of subjects) and no home made saline was used. All the contaminating organisms were shown to possess the enzyme catalase that breaks down hydrogen peroxide to oxygen and water. The polymicrobial nature of the biofilms found in many contact lens cases is illustrated electron micrographically. CONCLUSION--Based on data from this and previous studies, the authors conclude with recommendations for contact lens wearers: (1) regular scrubbing of contact lens case interior to disrupt biofilms; (2) exposure of contact lens case to very hot water (> or = 70 degrees C) will kill Acanthamoeba contaminants; (3) allow contact lens case to air dry between uses; (4) if hydrogen peroxide disinfection is preferred, use a two step system; (5) replace contact lens case regularly. Images PMID:7626578

  17. Characterization of lens based photoacoustic imaging system

    Directory of Open Access Journals (Sweden)

    Kalloor Joseph Francis

    2017-12-01

    Full Text Available Some of the challenges in translating photoacoustic (PA imaging to clinical applications includes limited view of the target tissue, low signal to noise ratio and the high cost of developing real-time systems. Acoustic lens based PA imaging systems, also known as PA cameras are a potential alternative to conventional imaging systems in these scenarios. The 3D focusing action of lens enables real-time C-scan imaging with a 2D transducer array. In this paper, we model the underlying physics in a PA camera in the mathematical framework of an imaging system and derive a closed form expression for the point spread function (PSF. Experimental verification follows including the details on how to design and fabricate the lens inexpensively. The system PSF is evaluated over a 3D volume that can be imaged by this PA camera. Its utility is demonstrated by imaging phantom and an ex vivo human prostate tissue sample.

  18. Freeform micromachining of an infrared Alvarez lens

    Science.gov (United States)

    Smilie, Paul J.; Dutterer, Brian S.; Lineberger, Jennifer L.; Davies, Matthew A.; Suleski, Thomas J.

    2011-02-01

    In 1967, Luis Alvarez introduced a novel concept for a focusing lens whereby two transmitting elements with cubic polynomial surfaces yield a composite lens of variable focal length with small lateral shifts. Computer simulations have demonstrated the behavior of these devices, but fabricating the refractive cubic surfaces of the types needed with adequate precision and depth modulation has proven to be challenging using standard methods, and, to the authors' knowledge, Alvarez lens elements have not been previously machined in infrared materials. Recent developments in freeform diamond machining capability have enabled the fabrication of such devices. In this paper, we discuss the fabrication of freeform refractive Alvarez elements in germanium using diamond micro-milling on a five-axis Moore Nanotech® 350FG Freeform Generator. Machining approaches are discussed, and measurements of surface figure and finish are presented. Initial experimental tests of optical performance are also discussed.

  19. Invited review article: the electrostatic plasma lens.

    Science.gov (United States)

    Goncharov, Alexey

    2013-02-01

    The fundamental principles, experimental results, and potential applications of the electrostatic plasma lens for focusing and manipulating high-current, energetic, heavy ion beams are reviewed. First described almost 50 years ago, this optical beam device provides space charge neutralization of the ion beam within the lens volume, and thus provides an effective and unique tool for focusing high current beams where a high degree of neutralization is essential to prevent beam blow-up. Short and long lenses have been explored, and a lens in which the magnetic field is provided by rare-earth permanent magnets has been demonstrated. Applications include the use of this kind of optical tool for laboratory ion beam manipulation, high dose ion implantation, heavy ion accelerator injection, in heavy ion fusion, and other high technology.

  20. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-12-19

    The gain of an antenna can be enhanced through the integration of a lens, however this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, with a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB giving a peak gain of about 12.9 dBi at 8.8 GHz.

  1. An "ESA-affordable" Laue-lens

    DEFF Research Database (Denmark)

    Lund, Niels

    2005-01-01

    With ESA's INTEGRAL mission gamma-ray astronomy has advanced to the point where major scientific advances must be expected from detailed studies of the many new point sources. The interest in developing focusing telescopes operating in the soft gamma-ray regime up to 1 MeV is therefore mounting r...... constraints of a specific medium size launch vehicle. The introduction of the lens mass as a primary design driver has some surprising effects for the choice of material for the crystals and new tradeoff considerations are introduced....... rapidly. Telescopes based on Laue diffraction of gamma-rays from crystals appear as one promising route, although the practical difficulties of realizing a large scale Laue lens are certainly not small. In this paper I have attempted to develop an optimized lens design considering the size and mass...

  2. The effectiveness of soft contact lens disinfection systems against Acanthamoeba on the lens surface.

    Science.gov (United States)

    Liedel, K K; Begley, C G

    1996-03-01

    This investigation compared the efficacy of three widely used contact lens disinfection systems against an ocular isolate of Acanthamoeba polyphaga. Twenty-seven worn Ciba NewVues lenses were quartered, heat sterilized and inoculated with Acanthamoeba. Lens quarters were then randomly assigned to three experimental groups, with Group A lenses exposed to cleaner and saline rinse only, Group B to disinfection only, and Group C to both cleaner and disinfection. One quarter of each lens served as a control and the other three quarters were experimental. Quantification of viable Acanthamoeba remaining on the lens was performed after each step of the disinfection process. Group A lenses showed no significant difference between the treatments, or the treatments and the control. Group B lenses demonstrated a significant difference (p = 0.0001) between the treatments and the control. In Group C (cleaning and disinfection), the control lens quarters were significantly different (p = 0.037) from the experimental group, but there was no significant difference between the treatments. All three disinfection regimens were very effective in reducing the number of viable Acanthamoeba on the contact lens surface. In the absence of proper cleaning (Group B), AOSept was the most effective of the three. These results also show the importance of thoroughly rubbing the contact lens surface to decrease the number of Acanthamoeba.

  3. Non-compliance with lens care and maintenance in diabetic contact lens wearers.

    Science.gov (United States)

    O'Donnell, Clare; Efron, Nathan

    2004-11-01

    We hypothesize that diabetic contact lens wearers may represent a special group displaying higher levels of compliance with their lens care regimens as a result of learned behaviour relating to maintenance of their diabetic condition. To test this hypothesis, a prospective, single centre, controlled, masked study was performed whereby 29 diabetic contact lens patients and 29 non-diabetic control subjects were issued with disposable hydrogel contact lenses and a multipurpose lens care regimen. All participants were given identical instruction on lens care and maintenance. Compliance levels were assessed at a 12-month aftercare appointment by demonstration and questionnaire. Twenty-four different aspects of compliance were scored, 12 by observation and 12 by questionnaire report, of which only two showed a significant difference between the diabetic and control groups. Although the combined population of contact lens wearers was generally compliant, there were examples of non-compliance in both groups. Neither the duration of diabetes nor the degree of metabolic control appeared to have a significant effect on compliance. The results suggest that eye care practitioners cannot assume that diabetic patients will be more compliant with contact lens care and maintenance than non-diabetic patients.

  4. Design of a secondary lens using gaussian function

    Science.gov (United States)

    Anh, Nguyen Doan Quoc; Long, Nguyen Ngoc; Van Phuoc, Nguyen; Voznak, Miroslav; Zdralek, Jaroslav

    2018-04-01

    In the article, it is recognized that the high-intensity discharge (HID) fishing lamp becomes obsolete, so we designed a free secondary lens for an LED fishing/working lamp (LFWL) to serve the lighting needs of fishing and the on-board activities on fishing boats through gaussian decomposition for taking the place it. The results proved that it is really useful to the board, sea-surface, and underwater. Moreover, the lighting efficiency of 91 % with the power consumption reducing more than 3 times could be achieved when the proposed LED fishing/working lamps are used instead of the HID fishing lamps.

  5. Susceptibility of Acanthamoeba castellanii to contact lens disinfecting solutions.

    Science.gov (United States)

    Zanetti, S; Fiori, P L; Pinna, A; Usai, S; Carta, F; Fadda, G

    1995-01-01

    A corneal isolate of Acanthamoeba castellanii was exposed to commercial contact lens disinfecting solutions containing hydrogen peroxide, benzalkonium chloride, polyaminopropyl biguanide, polyquaternium 1, and chlorhexidine-thimerosal. The minimum trophozoite amebicidal concentration and exposure times required to kill trophozoites and cysts were determined. Solutions containing hydrogen peroxide or chlorhexidine-thimerosal were active against both trophozoites and cysts. The benzalkonium chloride-based solution was effective only against trophozoites. Solutions containing polyaminopropyl biguanide or polyquaternium 1 were completely ineffective. The need for adequate exposure times must be stressed. PMID:7492111

  6. Analytic models of plausible gravitational lens potentials

    International Nuclear Information System (INIS)

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune

    2009-01-01

    Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sérsic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sérsic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses

  7. 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

  8. The corneal stroma during contact lens wear.

    Science.gov (United States)

    Jalbert, Isabelle; Stapleton, Fiona

    2005-03-01

    Recent technological advances have lead to novel descriptions of the microanatomy of the corneal stroma. In the first section of this review, these findings and the role they play in the maintenance of vital properties such as corneal transparency, mechanical strength, homeostasis, wound-healing response and metabolism are described. In the second part, contact lens induced stromal alterations such as acidosis, oedema, striae, thinning and opacities are reviewed as well as the more recently described phenomenon of microdot deposits and keratocyte loss with an emphasis on how lens wearing stromal effects can be minimised.

  9. Rotman lens for mm-wavelengths

    Science.gov (United States)

    Hall, Leonard T.; Hansen, Hedley J.; Abbott, Derek

    2002-11-01

    The 77 GHz band has been reserved for intelligent cruise control in luxury cars and some public transport services in America and the United Kingdom. The Rotman lens offers a cheap and compact means to extend the single beam systems generally used, to fully functional beam staring arrangements. Rotman lenses have been built for microwave frequencies with limited success. The flexibility of microstrip transmission lines and the advent of fast accurate simulation packages allow practical Rotman lenses to be designed at mm-wavelengths. This paper discusses the limitations of the conventional design approach and predicts the performance of a new Rotman lens designed at 77 GHz.

  10. Pulse transformer for the AA lithium lens

    CERN Document Server

    CERN PhotoLab

    1980-01-01

    The antiprotons emanating from the target were initially focused by a magnetic horn. Later on, a Li-lens was used during operation for the SPS collider, until 1992. A Li-rod (130 mm long, 34 mm in diameter) constituted the secondary of a 1:23 pulse-transformer. The half-sine pulse rose to 1000 kA in 900 microsec. The angular acceptance was 95 mrad. In operation after 1992, for LEAR only, a more modest Li-lens was used (155 mm long, diameter 20 mm, 480 kA, risetime 240 microsec, angular acceptance 75 mrad).

  11. Immunochemical analyses of soluble lens proteins in some marine fishes

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    Soluble eye lens proteins of 10 fishes, belonging to the families Clupeidae, Hemirhamphidae, Lactaridae, Scombridae, Stromatidae, Psettodidae, Bothidae and Soleidae were studied by immunoelectrophoresis using the lens antiserum of Sardinella...

  12. IOL Implants: Lens Replacement and Cataract Surgery (Intraocular Lenses)

    Science.gov (United States)

    ... Cataract Surgery vs. Laser-Assisted Cataract Surgery Cataract Vision Simulator Cataract Pictures and Videos: What Do ... Mar. 27, 2018 An intraocular lens (or IOL) is a tiny, artificial lens for the eye. It replaces the eye's ...

  13. Lens autofluorescence is not increased at high altitude

    DEFF Research Database (Denmark)

    Kessel, Line; Kofoed, Peter Kristian; Zubieta-Calleja, Gustavo

    2010-01-01

    PURPOSE: To study the relation between ambient environmental ultraviolet radiation exposure and lens fluorescence. METHODS: Non-invasive lens fluorometry measurements were compared in healthy Bolivian and Danish subjects. Background ultraviolet radiation was 4.5 times higher in Bolivia than in De...... living at sea level at 55 degrees northern latitude. These results suggest that lens ageing, as assessed by lens autofluorometry, is independent of exposure to ultraviolet radiation....

  14. 21 CFR 886.1420 - Ophthalmic lens gauge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic lens gauge. 886.1420 Section 886.1420...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1420 Ophthalmic lens gauge. (a) Identification. An ophthalmic lens gauge is a calibrated device intended to manually measure the curvature of a...

  15. 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 ...

  16. 21 CFR 800.10 - Contact lens solutions; sterility.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Contact lens solutions; sterility. 800.10 Section...) MEDICAL DEVICES GENERAL Requirements for Specific Medical Devices § 800.10 Contact lens solutions... ophthalmic use, including contact lens solutions, should be sterile. It is further evident that such...

  17. Initial Experience With Posterior Chamber Intraocular Lens Implant ...

    African Journals Online (AJOL)

    The results of extracapsular cataract extraction with posterior chamber intraocular lens implant at the Jos University Teaching Hospital are reviewed. The results suggest that despite lack of facilities to calculate the lens power for emmetropia, the use of a standard lens of about 19.0D will provide a good number of our ...

  18. Vitrectorhexis and lens aspiration with posterior chamber intraocular lens implantation in spherophakia.

    Science.gov (United States)

    Al-Haddad, Christiane; Khatib, Lama

    2012-07-01

    We describe a technique that uses the vitrector to perform successful lens aspiration and posterior chamber intraocular lens (IOL) implantation in children with spherophakia and anterior lens subluxation. After an anterior chamber maintainer is placed, the ocutome is introduced through a limbal incision to perform a circular vitrectorhexis to avoid excessive manipulation of the unstable lens followed by gentle cortex aspiration. A foldable IOL is injected into the sulcus (3-piece IOL) or bag (1-piece IOL) if the capsule is sufficiently stable. Through a pars plana incision, the ocutome is then used to perform a posterior capsulotomy to prevent late posterior capsule opacification. In our patient, sulcus IOL placement was more stable than in-the-bag placement. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. Phospholipids and their degrading enzyme in the tears of soft contact lens wearers.

    Science.gov (United States)

    Yamada, Masakazu; Mochizuki, Hiroshi; Kawashima, Motoko; Hata, Seiichiro

    2006-12-01

    Low tear phospholipids levels are associated with tear film instability in soft contact lens wearers. We assayed levels of phospholipids and their degrading enzyme secretory phospholipase A2 (sPLA2) both in tears and deposited on contact lenses composed of 2 hydrophilic materials after 1 day of routine use. Polymacon (Medalist; FDA group 1, low water/nonionic) and Etafilcon A (One Day Acuvue; group 4, high water/ionic) contact lenses were worn for 12 hours by 16 experienced contact lens wearers. Phospholipids in tear fluids and deposited on contact lenses were estimated by phosphorus determination with ammonium molybdate through enzymatic digestion. Double-antibody sandwich ELISA was used to determine group IIa sPLA2 concentrations, and sPLA2 activity was assayed using 1,2-diheptanoyl thio-phosphatidylcholine as substrate. Phospholipids concentrations in tears with Polymacon and Etafilcon A were 186 +/- 39 and 162 +/- 33 microg/mL, respectively. The latter concentration was significantly lower than that observed in the same subjects when not wearing contact lenses (P = 0.0023). In tears, both group IIa sPLA2 concentrations and enzymatic activity remained unchanged, regardless of lens wearing. However, Etafilcon A (0.57 +/- 0.09 microg/lens) showed more group IIa sPLA2 deposition than Polymacon (0.01 +/- 0.01 microg/lens; P < 0.001). Furthermore, group IIa sPLA2 deposited on Etafilcon A but not on Polymacon lenses retained its enzymatic activity. Significant differences of group IIa sPLA2 deposition were found in the 2 lenses tested. Such deposition might induce phospholipid hydrolysis in tears and thereby promote tear film instability in hydrophilic contact lens wearers.

  20. Solar powered desalination system using Fresnel lens

    Science.gov (United States)

    Sales, M. T. B. F.

    2016-11-01

    The Philippines is surrounded by coastal areas and these areas can be a potential source for potable water. This study aims to design and construct a solar powered desalination system using Fresnel lens. The experimental study was conducted using polluted salt water for the sample and desalination was carried out using the designed system. The desalination system was composed of the solar concentrator, solar still and the condenser system. The Fresnel lens was made of acrylic plastic and was an effective solar concentrator. Solar stills made of dark colored glass bottles were effective in absorbing the solar energy. The condenser system made of polybutylene and polystyrene were effective in condensing the vapor at ambient temperature. The shortest time of vaporization of the salt water was at 293 sec and the optimum angle of position of the lens was 36.42°. The amount of condensate collected was directly proportional to the amount of salt water in the solar still. The highest mean efficiency of the designed set-up was 34.82%. The water produced by the solar powered desalination system using Fresnel lens passed the standards set by WHO (World Health Organization) for drinking water.

  1. Electronic states in a quantum lens

    International Nuclear Information System (INIS)

    Rodriguez, Arezky H.; Trallero-Giner, C.; Ulloa, S. E.; Marin-Antuna, J.

    2001-01-01

    We present a model to find analytically the electronic states in self-assembled quantum dots with a truncated spherical cap (''lens'') geometry. A conformal analytical image is designed to map the quantum dot boundary into a dot with semispherical shape. The Hamiltonian for a carrier confined in the quantum lens is correspondingly mapped into an equivalent operator and its eigenvalues and eigenfunctions for the corresponding Dirichlet problem are analyzed. A modified Rayleigh-Schro''dinger perturbation theory is presented to obtain analytical expressions for the energy levels and wave functions as a function of the spherical cap height b and radius a of the circular cross section. Calculations for a hard wall confinement potential are presented, and the effect of decreasing symmetry on the energy values and eigenfunctions of the lens-shape quantum dot is studied. As the degeneracies of a semicircular geometry are broken for b≠a, our perturbation approach allows tracking of the split states. Energy states and electronic wave functions with m=0 present the most pronounced influence on the reduction of the lens height. The method and expressions presented here can be straightforwardly extended to deal with more general Hamiltonians, including strains and valence-band coupling effects in Group III--V and Group II--VI self-assembled quantum dots

  2. Surgical treatment of hereditary lens subluxations.

    Science.gov (United States)

    Ozdek, Sengul; Sari, Ayca; Bilgihan, Kamil; Akata, Fikret; Hasanreisoglu, Berati

    2002-01-01

    To evaluate the effectiveness and results of pars plana vitreolensectomy approach with transscleral fixation of intraocular lens in hereditary lens subluxations. Fifteen eyes of 9 consecutive patients with a mean age of 12.8+/-6.2 years (6-26 years) with hereditary lens subluxation were operated on and the results were evaluated in a prospective study. Surgery was considered if best spectacle corrected visual acuity (BSCVA) was less than 20/70. All eyes underwent a 2-port pars plana vitreolensectomy and transscleral fixation of an intraocular lens (IOL). The mean follow-up period was 12.6+/-7.5 months (6-22 months). There was no major intraoperative complication. Preoperatively, 8 eyes (53.3%) had a BSCVA of counting fingers (CF) and 7 eyes (46.6%) had a BSCVA of 20/200 to 20/70. Postoperatively, 14 eyes (93.3%) had a BSCVA of 20/50 or better. None of the patients had IOL decentration or intraocular pressure (IOP) increase during the follow-up period. There was a macular hole formation in 1 eye postoperatively. The early results of pars plana vitreolensectomy with IOL implantation using scleral fixation technique had shown that it not only promises a rapid visual rehabilitation but it is also a relatively safe method. More serious complications, however, may occur in the long term.

  3. READING SCRIPTURE THROUGH A MYSTICAL LENS

    African Journals Online (AJOL)

    Reading scripture through a mystical lens. 144 the illuminatory function of scripture which confirms and explains experience, rather than in its philological or scientific status. Elisabeth often juxtaposes several texts when quoting from memory and the biblical foundation of her writings is clearly evident in certain cases which ...

  4. 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.

  5. Effects of melatonin on Wi-Fi-induced oxidative stress in lens of rats.

    Science.gov (United States)

    Tök, Levent; Nazıroğlu, Mustafa; Doğan, Salih; Kahya, Mehmet Cemal; Tök, Ozlem

    2014-01-01

    Melatonin has been considered a potent antioxidant that detoxifies a variety of reactive oxygen species in many pathophysiological states of eye. The present study was designed to determine the effects of Wi-Fi exposure on the lens oxidant, antioxidant redox systems, as well as the possible protective effects of melatonin on the lens injury induced by electromagnetic radiation (EMR). Thirty-two rats were used in the current study and they were randomly divided into four equal groups as follows: First and second groups were cage-control and sham-control rats. Rats in third group were exposed to Wi-Fi (2.45 GHz) for duration of 60 min/day for 30 days. As in the third group, the fourth group was treated with melatonin. The one-hour exposure to irradiation in second, third and fourth took place at noon each day. Lipid peroxidation levels in the lens were slightly higher in third (Wi-Fi) group than in cage and sham control groups although their concentrations were significantly (P Wi-Fi group than in cage and sham control groups although GSH-Px (P Wi-Fi + melatonin group than in Wi-Fi group. There are poor oxidative toxic effects of one hour of Wi-Fi exposure on the lens in the animals. However, melatonin supplementation in the lens seems to have protective effects on the oxidant system by modulation of GSH-Px activity.

  6. Concurrent acanthamoeba and Fusarium keratitis with silicone hydrogel contact lens use.

    Science.gov (United States)

    Lee, Barry; Grossniklaus, Hans E; Edelhauser, Henry F

    2010-02-01

    To report a case of simultaneous Acanthamoeba and Fusarium keratitis associated with no-rub multipurpose contact lens solution and silicone hydrogel contact lens use. Observational case report. A 39-year-old woman was referred for worsening of a presumed bacterial corneal ulcer in the setting of silicone hydrogellens wear with occasional overnight wear, no-rub multipurpose contact lens solution use, and combined topical antibiotic/corticosteroid treatment. Initial corneal scrapings and culture confirmed Acanthamoeba and Fusarium solani, corroborated by in vivo confocal microscopy findings, yet despite topical chlorhexidine 0.02%, propamidine 1%,neomycin/polymyxin B ointment, and natamycin 5% along with oral itraconazole, the ulcer worsened. Four days after amoebic and fungal therapy initiation, it was discovered that the pharmacy accidentally dispensed neomycin/polymyxin B/dexamethasone, and despite immediate discontinuation, therapeutic penetrating keratoplasty from corneal melting was ultimately required. Corneal histopathology confirmed the presence of amoebic cysts and fungal elements. Coexisting infection with Acanthamoeba and Fusarium species can occur in contact lens wear. Atypical infection must be considered in patients with corneal ulcers demonstrating poor therapeutic response in the setting of contact lens wear. Corticosteroids should be used with extreme caution in contact lens–related corneal infections, especially when the diagnosis remains unknown because they can lead to acceleration of active infection and keratolysis.

  7. [Global Allergy and Asthma European Network (GA2LEN) addresses the epidemic of allergy and asthma].

    Science.gov (United States)

    Panzer, Petr Cáp Petr Burney Peter Zuberbier Torsten; van Cauvenberg, Paul; Bousquet, Jean

    2010-01-01

    Allergic diseases represent a major health problem in Europe. They are increasing in prevalence, severity and costs. GA2LEN, an FP6 Network of Excellence, was created in 2005 as a vehicle to ensure excellence in research bringing together research and clinical institutions to combat fragmentation in the European research area and to tackle Allergy in its globality. GA2LEN benefited greatly from the voluntary efforts of researchers who are strongly committed to this model of pan-European collaboration. The network was organized in order to increase networking for scientific projects in allergy and asthma around Europe and to make GA2LEN the world leader in the field. Besides these activities, research has been jointly made and the first papers are being published. GA2LEN achievements in general can be grouped as those for a durable infrastructure built up during the project phase those which are project-related work based on these novel infrastructures, and the development and implementations of guidelines. The major achievements of GA2LEN are reported in this paper.

  8. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    Czech Academy of Sciences Publication Activity Database

    Konvalina, Ivo; Müllerová, Ilona

    2011-01-01

    Roč. 645, č. 1 (2011), s. 55-59 ISSN 0168-9002 R&D Projects: GA ČR GAP102/10/1410; GA AV ČR IAA100650902; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : cathode lens * compound objective lens * aberration coefficients * spot size * field calculations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.207, year: 2011

  9. Effect of pulsed hollow electron-lens operation on the proton beam core in LHC

    Energy Technology Data Exchange (ETDEWEB)

    Fitterer, Miriam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Valishev, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-11-08

    Collimation with hollow electron beams is currently one of the most promising concepts for active halo control in the HL-LHC. In order to further increase the diffusion rates for a fast halo removal as e.g. desired before the squeeze, the electron lens (e-lens) can be operated in pulsed mode. In case of profile imperfections in the electron beam the pulsing of the e-lens induces noise on the proton beam which can, depending on the frequency content and strength, lead to emittance growth. In order to study the sensitivity to the pulsing pattern and the amplitude, a beam study (machine development MD) at the LHC has been proposed for August 2016 and we present in this note the preparatory simulations and estimates.

  10. Nanosecond KTN varifocal lens without electric field induced phase transition

    Science.gov (United States)

    Zhu, Wenbin; Chao, Ju-Hung; Chen, Chang-Jiang; Campbell, Adrian; Henry, Michael; Yin, Stuart (Shizhuo); Hoffman, Robert C.

    2017-08-01

    This paper presents a nanosecond speed KTN varifocal lens. The tuning principle of varifocal lens is based on the high-speed refractive index modulation from the nanosecond speed tunable electric field. A response time on the order of nanoseconds was experimentally demonstrated, which is the fastest varifocal lens reported so far. The results confirmed that the tuning speed of the KTN varifocal lens could be significantly increased by avoiding the electric field induced phase transition. Such a nanosecond speed varifocal lens can be greatly beneficial for a variety of applications that demand high speed axial scanning, such as high-resolution 3D imaging and high-speed 3D printing.

  11. Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

    Science.gov (United States)

    Chhabra, Mahendra

    The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

  12. Subjective assessment of contact lens wear by army aircrew.

    Science.gov (United States)

    Lattimore, M R; Cornum, R L

    1993-07-01

    Because 23% of Army aviators are ametropic, contact lenses have drawn increased attention as a spectacle substitute to solve system compatibility problems. From November 1988 until October 1991, a series of contact lens research protocols were conducted to develop a comprehensive database on contact lens wear in varied environments. Questionnaires were used to assess suitability and acceptability of routine contact lens wear. Responses from 202 subjects were obtained from September 1989 through September 1991. The questions explored operational and safety of flight issues of contact lens wear. Subjects overwhelmingly approved of contact lens use in all settings: 95% expressed greater combat readiness and effectiveness with contact lenses, 98% felt contact lens use (and maintenance) in the cockpit had no adverse impact on safety of flight, and 98% endorsed the routine use of contact lenses. These data highlight Army aircrew acceptance of contact lens use.

  13. Pars Plana Vitrectomy in Treatment of Lens Injury

    Directory of Open Access Journals (Sweden)

    Remzi Avcı

    2013-01-01

    Full Text Available Lens injury due to traumas may present as loss of capsule integrity, cataract, lens subluxation, or lens luxation. In addition, lens subluxation and lens luxation may occur in pseudophakic patients due to trauma. Clear corneal, scleral or sclero-corneal phacoemulsification surgery, pars plana vitrectomy, pars plana vitrectomy with phaco-fragmentation, or pars plana vitrectomy with removal through corneal incision techniques are used in the treatment of lens injury due to traumas. Intraocular lens can be implanted in the bag, sulcus, or anterior chamber during the surgery. Depending on the circumstances, scleral fixated intraocular lenses or iris-claw lenses may also be preferred. Rehabilitation of such patients is not of a great concern today, with the advanced level of vitreoretinal surgery and cataract surgery techniques and with the current state of technology. (Turk J Ophthalmol 2013; 43: 51-4

  14. Photoferroelectric Image Storage in PLZT Ceramics.

    Science.gov (United States)

    1981-03-01

    conductivity a3 (0) of reqion (3). For example, for 144 5 x 1 4 400 keV Ar/c 2 , which has x3 0.5 vim , we find that 0i/ 03(0) - 340. IFor I * 0, if we...unlimited. 17. DISTRIBUTION STATEMENT (of te aebEdee inmE Bla 20, it Efte am Rai ) N/A IS. SUPPLEMENTARY NOTES The findings in this report are not to be

  15. Echo scintillation Index affected by cat-eye target's caliber with Cassegrain lens

    Science.gov (United States)

    Shan, Cong-miao; Sun, Hua-yan; Zhao, Yan-zhong; Zheng, Yong-hui

    2015-10-01

    The optical aperture of cat-eye target has the aperture averaging effect to the active detecting laser of active laser detection system, which can be used to identify optical targets. The echo scintillation characteristics of the transmission-type lens target have been studied in previous work. Discussing the differences of the echo scintillation characteristics between the transmission-type lens target and Cassegrain lens target can be helpful to targets classified. In this paper, the echo scintillation characteristics of Cat-eye target's caliber with Cassegrain lens has been discussed . By using the flashing theory of spherical wave in the weak atmospheric turbulence, the annular aperture filter function and the Kolmogorov power spectrum, the analytic expression of the scintillation index of the cat-eye target echo of the horizontal path two-way transmission was given when the light is normal incidence. Then the impact of turbulence inner and outer scale to the echo scintillation index and the analytic expression of the echo scintillation index at the receiving aperture were presented using the modified Hill spectrum and the modified Von Karman spectrum. Echo scintillation index shows the tendency of decreasing with the target aperture increases and different ratios of the inner and outer aperture diameter show the different echo scintillation index curves. This conclusion has a certain significance for target recognition in the active laser detection system that can largely determine the target type by largely determining the scope of the cat-eye target which depending on echo scintillation index.

  16. Spontaneous dislocation of lens bag with acrylic lens after uneventful cataract surgery - unusual complication of cataract surgery.

    Science.gov (United States)

    Shah, Mehul A; Shah, Shreya M; Mehta, Ruchir; Shah, Prerna

    2015-01-01

    Spontaneous dislocation of intraocular lens with bag is rare. We report a case of a 56-year-old male who presented with spontaneous anterior dislocation of an in-the-bag intraocular lens 3 years after manual small incision cataract surgery. He had undergone manual small incision cataract surgery with foldable acrylic intraocular lens implantation, and 18 months after cataract surgery ND: YAG capsulotomy with uneventful post capsulotomy follow-up. 17 months after capsulotomy, the patient presented with sudden decrease of vision. On anterior segment examination, the intraocular lens with bag was dislocated into the anterior chamber. It was managed with intraocular lens explantation with bag, anterior vitrectomy and sclera fixated intraocular lens. Spontaneous intraocular lens dislocation with bag is possible after 1.5 years of uneventful surgery which may be managed using different techniques.

  17. Gravitational Lens Time Delays Using Polarization Monitoring

    Directory of Open Access Journals (Sweden)

    Andrew Biggs

    2017-11-01

    Full Text Available Gravitational lens time delays provide a means of measuring the expansion of the Universe at high redshift (and therefore in the ‘Hubble flow’ that is independent of local calibrations. It was hoped that many of the radio lenses found in the JVAS/CLASS survey would yield time delays as these were selected to have flat spectra and are dominated by multiple compact components. However, despite extensive monitoring with the Very Large Array (VLA, time delays have only been measured for three of these systems (out of 22. We have begun a programme to reanalyse the existing VLA monitoring data with the goal of producing light curves in polarized flux and polarization position angle, either to improve delay measurements or to find delays for new sources. Here, we present preliminary results on the lens system B1600+434 which demonstrate the presence of correlated and substantial polarization variability in each image.

  18. Complications caused by contact lens wearing.

    Science.gov (United States)

    Beljan, Jasna; Beljan, Kristina; Beljan, Zdravko

    2013-04-01

    Complications in wearing contact lenses are very rare and caused by poor maintenance, over-extended wear and wearing of contact lenses in a polluted environment. Regular control by a professional person can efficiently reduce the number of complications. This paper describes the most common risks factors for complications, and complications of wearing contact lenses with the classification according to the anatomic parts of the eye: eyelids, tear film, limbus, corneal epithelium, corneal stroma and corneal endothelium. Every complication has been described by the characteristic signs and symptoms, etiology and pathology, as well as therapy and prognosis. The paper describes how to select adequate customers as contact lens users, with proper education in order to ensure minimal incidence of complications due to contact lens wear, thus attracting a lot of satisfied and healthy customers.

  19. Effects of Temperature on Hybrid Lens Performance

    Science.gov (United States)

    Askins, Steve; Victoria, Marta; Herrero, Rebeca; Domínguez, César; Antón, Ignacio; Sala, Gabriel

    2011-12-01

    In hybrid Silicone-on-glass Fresnel lenses, an optical silicone is molded onto a glass substrate and forms the Fresnel structure. These lenses offer a cost effective solution as a primary optical element in point-focus concentrator photovoltaic modules, as well as performance advantages. However, these lenses have a high performance variation with temperature due both to the change in index of refraction of silicone as well as to deformations in the facets caused by coefficient of thermal expansion (CTE) mismatch. In this study we perform measurements of the light flux at the focal plane of a family of SOG lenses, varying temperature and lens-to-receiver distances. The effect of varying silicone cure temperature and the depth of the silicone between the lens and the glass substrate on temperature dependence was investigated. A preliminary computer model of this behavior is presented.

  20. A Tribute to Dr. Willy Lens

    Directory of Open Access Journals (Sweden)

    Maarten Vansteenkiste

    2016-07-01

    Full Text Available Dr. Willy Lens, born on December 10th, 1943, passed away on August 29th, 2014. With his passing, the motivation community has lost a seminal member, a mentor, and a friend. Dr. Lens – a Fellow of the Association for Psychological Science and Founding Fellow of the American Educational Research Association – made fundamental contributions to the study of motivation both through his own work and through his caring and thoughtful mentorship of a large community of scholars. With this tribute, we want to honor Dr. Willy Lens’ significance to psychology and education as well as his positive influence, both personally and professionally, on the lives of dozens of scholars. With his contagious enthusiasm and caring mentorship, Willy was an example for our academic community and with this tribute we express our gratitude for the privilege to have collaborated with him.

  1. 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.

  2. Intraocular lens implantation in microphthalmic patients.

    Science.gov (United States)

    Sinskey, R M; Amin, P; Stoppel, J

    1992-09-01

    Microphthalmos is a developmental disorder of the eye consisting of a smaller than normal eye. This disorder can present as an isolated condition or associated with other systemic alterations. It is not uncommon for patients with microphthalmos to have congenital cataracts along with other ocular and systemic abnormalities. This paper reports the experience with 11 microphthalmic eyes of seven patients who had primary or secondary intraocular lens (IOL) implantation over a six-year period from 1985 to 1991. In all cases the IOL had a 13.5 mm or 14.0 mm overall diameter and a 6.0 mm or 6.5 mm optic. It was difficult to obtain documentation of objective visual improvement in many of these cases because of the associated nystagmus. However, all patients reported subjective improvements. These results suggest that with proper technique and lens selection microphthalmic patients should be considered for IOL implantation with relative safety and success.

  3. Pulser for the Tevatron electron lens gun

    Energy Technology Data Exchange (ETDEWEB)

    Iouri Terechkine et al.

    2004-05-18

    To compensate for beam-beam interaction in Tevatron, an ''electron lens'' is considered to be an effective instrument. When a bunch of electrons with energy in the range (10-16) kV is overlapping with a bunch of antiprotons, the resulting focusing force for antiprotons can be adjusted by changing the electron beam current and by profiling its radial distribution. There exist several scenarios of how the system must function. According to one of them, an electron gun that supplies electrons must be fed by voltage pulses that follow with the frequency of antiproton bunches circulating in the Tevatron, which is about 2.5 MHz. To provide focusing tailored for each individual antiproton bunch, a modulator of the gun (pulser) must allow pulse-to-pulse voltage change. This report will cover main approaches to a design of a pulser for use with the gun of the Tevatron Electron Lens.

  4. Intraocular Lens Subluxation in Marfan Syndrome

    Science.gov (United States)

    Rodrigo, Bolaños-Jiménez; Paulina, López-Lizárraga E; Francesc, March de R; Eduardo, Telich-Tarriba J; Alejandro, Navas

    2014-01-01

    Purpose : Ectopia lentis (EL) is a major criteria for the diagnosis of Marfan syndrome, it may vary from an asymptomatic mild displacement to a significant subluxation that places the equator of the lens in the pupillary axis. The purpose of this work is to present the case of a patient with Marfan syndrome who received treatment for subluxation at our institution. Case Report : A 51-year-old female diagnosed with Marfan syndrome presented to the emergency department with bilateral eye redness, foreign body sensation and crusting around the eyes on awakening. She had the following history of cardiac and ophthalmologic complications, including: 1. Lens subluxation 2. High myopia 3. Aortic root dilation, 4. Mitral valve prolapse and 5. Tricuspid insufficiency. Conclusion : The ophthalmological management of Marfan patients is challenging and periodical follow-up is needed. Surgical versus conservative management is controversial, each case needs to be evaluated individually to analyze the risks and benefits of the procedures. PMID:25279020

  5. Assessment of the occupational eye lens dose for clinical staff in interventional radiology, cardiology and neuroradiology.

    Science.gov (United States)

    Omar, Artur; Kadesjö, Nils; Palmgren, Charlotta; Marteinsdottir, Maria; Segerdahl, Tony; Fransson, Annette

    2017-03-20

    In accordance with recommendations by the International Commission on Radiological Protection, the current European Basic Safety Standards has adopted a reduced occupational eye lens dose limit of 20 mSv yr -1 . The radiation safety implications of this dose limit is of concern for clinical staff that work with relatively high dose x-ray angiography and interventional radiology. Presented in this work is a thorough assessment of the occupational eye lens dose based on clinical measurements with active personal dosimeters worn by staff during various types of procedures in interventional radiology, cardiology and neuroradiology. Results are presented in terms of the estimated equivalent eye lens dose for various medical professions. In order to compare the risk of exceeding the regulatory annual eye lens dose limit for the widely different clinical situations investigated in this work, the different medical professions were separated into categories based on their distinct work pattern: staff that work (a) regularly beside the patient, (b) in proximity to the patient and (c) typically at a distance from the patient. The results demonstrate that the risk of exceeding the annual eye lens dose limit is of concern for staff category (a), i.e. mainly the primary radiologist/cardiologist. However, the results also demonstrate that the risk can be greatly mitigated if radiation protection shields are used in the clinical routine. The results presented in this work cover a wide range of clinical situations, and can be used as a first indication of the risk of exceeding the annual eye lens dose limit for staff at other medical centres.

  6. Performance of a Be Refractive Lens

    International Nuclear Information System (INIS)

    Smither, R.K.; Khounsary, A.M.; Mancini, D.C.; Saleem, K. Abu

    2004-01-01

    The performance of a beryllium compound refractive lens (CRL) was tested in the energy range of 11.5 to 8.0 keV. The beryllium refractive lens consists of 50 aligned, 1-mm-diameter, hollow spheres in a solid block of beryllium, 30 mm x 20 mm x 55 mm. The minimum web between each hollow sphere was 0.10 mm. The measured focal length of the lens for x-rays close to the axis of the beam was 147.7 cm +/- 2.0 cm at 10 keV and 120.2 +/- 2.0 cm at 9.1 keV. These values agree well with the theoretical values of 146.6 cm and 121.4 cm, respectively. The diameter of the best focus obtained at 10 keV was 35 μm horizontal and 45 μm vertical. For the modified version of the lens used in the 9.1 keV experiment these values were 25 μm horizontal and 35 μm vertical. The x-ray beam cross section for the 10 keV and the 9.1 keV experiments were 0.50 mm x 0.50 mm and 0.30 mm x 0.30 mm, respectively. The enhancement of the flux (photons per sq. mm) was 50:1 at 10 keV and 80:1 in the 9.1 keV experiment

  7. THE BOSS EMISSION-LINE LENS SURVEY. IV. SMOOTH LENS MODELS FOR THE BELLS GALLERY SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Yiping [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Bolton, Adam S.; Montero-Dorta, Antonio D.; Cornachione, Matthew A.; Zheng, Zheng; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Mao, Shude [Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084 (China); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Pérez-Fournon, Ismael; Marques-Chaves, Rui [Instituto de Astrofísica de Canarias, C/Vía Láctea, s/n, E-38205 San Cristóbal de La Laguna, Tenerife (Spain); Oguri, Masamune [Research Center for the Early Universe, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ménard, Brice, E-mail: yiping.shu@nao.cas.cn [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2016-12-20

    We present Hubble Space Telescope F606W-band imaging observations of 21 galaxy-Ly α emitter lens candidates in the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey (BELLS) for the GALaxy-Ly α EmitteR sYstems (BELLS GALLERY) survey. Seventeen systems are confirmed to be definite lenses with unambiguous evidence of multiple imaging. The lenses are primarily massive early-type galaxies (ETGs) at redshifts of approximately 0.55, while the lensed sources are Ly α emitters (LAEs) at redshifts from two to three. Although most of the lens systems are well fit by smooth lens models consisting of singular isothermal ellipsoids in an external shear field, a thorough exploration of dark substructures in the lens galaxies is required. The Einstein radii of the BELLS GALLERY lenses are, on average, 60% larger than those of the BELLS lenses because of the much higher source redshifts. This will allow for a detailed investigation of the radius evolution of the mass profile in ETGs. With the aid of the average ∼13× lensing magnification, the LAEs are frequently resolved into individual star-forming knots with a wide range of properties. They have characteristic sizes from less than 100 pc to several kiloparsecs, rest-frame far-UV apparent AB magnitudes from 29.6 to 24.2, and typical projected separations of 500 pc to 2 kpc.

  8. [Congenital lens subluxation: visual acuity outcomes and intraocular lens postoperative position].

    Science.gov (United States)

    Arraes, Caroline; Endriss, Daniela; Lobato, Francisco; Arraes, João; Ventura, Marcelo

    2010-01-01

    To evaluate the visual acuity outcomes and to investigate the intraocular lens (IOL) and endocapsular ring positions with ultrasound biomicroscopy in 17 eyes of 10 patients with congenital lens subluxation who underwent the same surgical technique, by the same surgeon. The study was performed in the ''Hospital de Olhos de Pernambuco'' and ''Fundação Altino Ventura''. The surgical technique consisted of phacoaspiration with implant of endocapsular ring and intraocular lens with one loop haptic amputated. The age varied from 7 to 22 years. Data on visual acuity (VA) before and after surgery, surgery follow-up period, and complications were analyzed. All patients underwent ultrasound biomicroscopy. The mean follow-up period was 2.8 years. There was a VA improvement in 17 (100%) eyes: in 12 eyes (70.6%) the visual acuity was better than 20/40; 4 (23.5%) ranged from 20/40 to 20/100, and 1 (5.9%) had visual acuity worse than 20/100, however better than the preoperative visual acuity. The posterior capsular opacification occurred in 10 eyes (58.9%). Ultrasound biomicroscopy showed that all IOL were partially decentralized, however without surpassing the pupil border limit. Endocapsular ring position was correct and there was a good capsular support in all cases. The evaluated surgical treatment provided good intraocular lens and endocapsular ring position, with VA improvement Thus, this technique is a viable, effective and safe option for the visual rehabilitation of patients with congenital lens subluxation.

  9. Two families of astrophysical diverging lens models

    Science.gov (United States)

    Er, Xinzhong; Rogers, Adam

    2018-03-01

    In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in the opposite sense to gravitational lensing, and is also of astrophysical interest. In fact, diverging lensing due to compact distributions of plasma has been proposed as an explanation for the extreme scattering events that produce frequency-dependent dimming of extragalactic radio sources, and may also be related to the refractive radio wave phenomena observed to affect the flux density of pulsars. In this work we study the behaviour of two families of astrophysical diverging lenses in the geometric optics limit, the power law, and the exponential plasma lenses. Generally, the members of these model families show distinct behaviour in terms of image formation and magnification, however the inclusion of a finite core for certain power-law lenses can produce a caustic and critical curve morphology that is similar to the well-studied Gaussian plasma lens. Both model families can produce dual radial critical curves, a novel distinction from the tangential distortion usually produced by gravitational (converging) lenses. The deflection angle and magnification of a plasma lens vary with the observational frequency, producing wavelength-dependent magnifications that alter the amplitudes and the shape of the light curves. Thus, multiwavelength observations can be used to physically constrain the distribution of the electron density in such lenses.

  10. Adaptive Liquid Lens Actuated by Droplet Movement

    Directory of Open Access Journals (Sweden)

    Chao Liu

    2014-08-01

    Full Text Available In this paper we report an adaptive liquid lens actuated by droplet movement. Four rectangular PMMA (Polymethyl Methacrylate substrates are stacked to form the device structure. Two ITO (Indium Tin Oxide sheets stick on the bottom substrate. One PMMA sheet with a light hole is inserted in the middle of the device. A conductive droplet is placed on the substrate and touches the PMMA sheet to form a small closed reservoir. The reservoir is filled with another immiscible non-conductive liquid. The non-conductive liquid can form a smooth concave interface with the light hole. When the device is applied with voltage, the droplet stretches towards the reservoir. The volume of the reservoir reduces, changing the curvature of the interface. The device can thus achieve the function of an adaptive lens. Our experiments show that the focal length can be varied from −10 to −159 mm as the applied voltage changes from 0 to 65 V. The response time of the liquid lens is ~75 ms. The proposed device has potential applications in many fields such as information displays, imaging systems, and laser scanning systems.

  11. 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)

  12. Compound refractive X-ray lens

    International Nuclear Information System (INIS)

    Nygren, D.R.; Cahn, R.; Cederstrom, B.; Danielsson, M.; Vestlund, J.

    2000-01-01

    An apparatus and method are disclosed for focusing X-rays. In one embodiment, his invention is a commercial-grade compound refractive X-ray lens. The commercial-grade compound refractive X-ray lens includes a volume of low-Z material. The volume of low-Z material has a first surface which is adapted to receive X-rays of commercially-applicable power emitted from a commercial-grade X-ray source. The volume of low-Z material also has a second surface from which emerge the X-rays of commercially-applicable power which were received at the first surface. Additionally, the commercial-grade compound refractive X-ray lens includes a plurality of openings which are disposed between the first surface and the second surface. The plurality of openings are oriented such that the X-rays of commercially-applicable power which are received at the first surface, pass through the volume of low-Z material and through the plurality openings. In so doing, the X-rays which emerge from the second surface are refracted to a focal point

  13. Metasurface axicon lens design at visible wavelengths

    Science.gov (United States)

    Alyammahi, Saleimah; Zhan, Qiwen

    2017-08-01

    The emerging field of metasurfaces is promising to realize novel optical devices with miniaturized flat format and added functionalities. Metasurfaces have been demonstrated to exhibit full control of amplitude, phase and polarization of electromagnetic waves. Using the metasurface, the wavefront of light can be manipulated permitting new functionalities such as focusing and steering of the beams and imaging. One optical component which can be designed using metasurfaces is the axicon. Axicons are conical lenses used to convert Gaussian beams into nondiffraction Bessel beams. These unique devices are utilized in different applications ranging from optical trapping and manipulation, medical imaging, and surgery. In this work, we study axicon lens design comprising of planar metasurfaces which generate non-diffracting Bessel beams at visible wavelengths. Dielectric metasurfaces have been used to achieve high efficiency and low optical loss. We measured the spot size of the resulted beams at different planes to demonstrate the non-diffraction properties of the resulted beams. We also investigated how the spot size is influenced by the axicon aperture. Furthermore, we examined the achromatic properties of the designed axicon. Comparing with the conventional lens, the metasurface axicon lens design enables the creation of flat optical device with wide range of depth of focus along its optical axis.

  14. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

    Baun, Christina; Falch Braas, Kirsten; D. Nielsen, Kamilla

    2015-01-01

    Radiation Dose to the Eye Lens: Does Positioning Really Matter? C. Baun1, K. Falch1, K.D. Nielsen2, S. Shanmuganathan1, O. Gerke1, P.F. Høilund-Carlsen1 1Department of Nuclear Medicine, Odense University Hospital, Odense C, Denmark. 2University College Lillebaelt, Odense, Denmark. Aim: The scan...... field in oncology patients undergoing eyes-to-thighs PET/CT must always include the base of the scull according to department guidelines. The eye lens is sensitive to radiation exposure and if possible it should be avoided to scan the eye. If the patient’s head is kipped backwards during the scan one...... might avoid including the eye in the CT scan without losing sufficient visualization of the scull base. The aim of this study was to evaluate the possibility of decreasing the radiation dose to the eye lens, simply by changing the head position, when doing the PET/CT scan from the base of the scull...

  15. Radiation dose to the lens and cataract formation

    International Nuclear Information System (INIS)

    Henk, J.M.; Whitelocke, R.A.F.; Warrington, A.P.; Bessell, E.M.

    1993-01-01

    The purpose of this work was to determine the radiation tolerance of the lens of the eye and the incidence of radiation-induced lens changes in patients treated by fractionated supervoltage radiation therapy for orbital tumors. Forty patients treated for orbital lymphoma and pseudotumor with tumor doses of 20--40 Gy were studied. The lens was partly shielded using lead cylinders in most cases. The dose to the germinative zone of the lens was estimated by measurements in a tissue equivalent phantom using both film densitometry and thermoluminescent dosimetry. Opthalmological examination was performed at 6 monthly intervals after treatment. The lead shield was found to reduce the dose to the germinative zone of the lens to between 36--50% of the tumor dose for Cobalt beam therapy, and to between 11--18% for 5 MeV x-rays. Consequently, the lens doses were in the range 4.5--30 Gy in 10--20 fractions. Lens opacities first appeared from between 3 and 9 years after irradiation. Impairment of visual acuity ensued in 74% of the patients who developed lens opacities. The incidence of lens changes was strongly dose-related. None was seen after doses of 5 Gy or lower, whereas doses of 16.5 Gy or higher were all followed by lens opacities which impaired visual acuity. The largest number of patients received a maximum lens dose of 15 Gy; in this group the actuarial incidence of lens opacities at 8 years was 57% with visual impairment in 38%. The adult lens can tolerate a total dose of 5 Gy during a fractionated course of supervoltage radiation therapy without showing any changes. Doses of 16.5 Gy or higher will almost invariably lead to visual impairment. The dose which causes a 50% probability of visual impairment is approximately 15 Gy. 10 refs., 4 figs., 1 tab

  16. 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.

  17. Cellular damage after total or partial x-irradiation of the rat lens epithelium

    International Nuclear Information System (INIS)

    Miller, R.C.

    1976-01-01

    The response of cells to a wound stimulus was used to study the effects of X-irradiation on cells of the rat lens epithelium. Either the entire lens or just the nasal half of the lens of the right eye of Holtzman rats was irradiated with 1000 rads of X-rays (250 kVp, 30 mA, filter = 1 mm Al + 1 / 4 mm Cu, HVL = 1 mm Cu). At various times after irradiation (1, 7, or 28 days in whole-irradiated lenses and 1, 4, 7, or 14 days in half-irradiated lenses) the lenses were wounded with a sharpened Hamilton microliter syringe. Samples of epithelia were obtained every 2 hours from 14 to 44 hours after wounding. Two hours before a scheduled sacrifice time, 5 μCi of tritiated thymidine ( 3 H-TdR) were topicaly applied to each eye. Two hours later, the animals were killed and their eyes enucleated. Then autoradiographs of whole mounts of the lens epithelia were prepared. The epithelial cells were then counted to determine DNA synthesis activity ( 3 H-TdR cell labeling), mitotic activity, and mitotic abnormalities

  18. Novel Scanning Lens Instrument for Evaluating Fresnel Lens Performance: Equipment Development and Initial Results (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, R.; Miller, D. C.; Kurtz, S. R.; Anton, I.; Sala, G.

    2013-07-01

    A system dedicated to the optical transmittance characterization of Fresnel lenses has been developed at NREL, in collaboration with the UPM. The system quantifies the optical efficiency of the lens by generating a performance map. The shape of the focused spot may also be analyzed to understand change in the lens performance. The primary instrument components (lasers and CCD detector) have been characterized to confirm their capability for performing optical transmittance measurements. Measurements performed on SoG and PMMA lenses subject to a variety of indoor conditions (e.g., UV and damp heat) identified differences in the optical efficiency of the evaluated lenses, demonstrating the ability of the Scanning Lens Instrument (SLI) to distinguish between the aged lenses.

  19. A high excitation magnetic quadrupole lens quadruplet incorporating a single octupole lens for a low spherical aberration probe forming lens system

    Science.gov (United States)

    Dou, Yanxin; Jamieson, David N.; Liu, Jianli; Li, Liyi

    2018-03-01

    This paper describes the design of a new probe forming lens system consisting of a high excitation magnetic quadrupole lens quadruplet that incorporates a single magnetic octupole lens. This system achieves both a high demagnification and a low spherical aberration compared to conventional high excitation systems and is intended for deployment for the Harbin 300 MeV proton microprobe for applications in space science and ion beam therapy. This relative simplicity of the ion optical design to include a single octupole lens minimizes the risks associated with the constructional and operational precision usually needed for the probe forming lens system and this system could also be deployed in microprobe systems that operate with less magnetically rigid ions. The design of the new system is validated with reference to two independent ion optical computer codes.

  20. Lens Crystallin Modifications and Cataract in Transgenic Mice Overexpressing Acylpeptide Hydrolase*

    Science.gov (United States)

    Santhoshkumar, Puttur; Xie, Leike; Raju, Murugesan; Reneker, Lixing; Sharma, K. Krishna

    2014-01-01

    The accumulation of crystallin fragments in vivo and their subsequent interaction with crystallins are responsible, in part, for protein aggregation in cataracts. Transgenic mice overexpressing acylpeptide hydrolase (APH) specifically in the lens were prepared to test the role of protease in the generation and accumulation of peptides. Cataract development was seen at various postnatal days in the majority of mice expressing active APH (wt-APH). Cataract onset and severity of the cataracts correlated with the APH protein levels. Lens opacity occurred when APH protein levels were >2.6% of the total lens protein and the specific activity, assayed using Ac-Ala-p-nitroanilide substrate, was >1 unit. Transgenic mice carrying inactive APH (mt-APH) did not develop cataract. Cataract development also correlated with N-terminal cleavage of the APH to generate a 57-kDa protein, along with an increased accumulation of low molecular weight (LMW) peptides, similar to those found in aging human and cataract lenses. Nontransgenic mouse lens proteins incubated with purified wt-APH in vitro resulted in a >20% increase in LMW peptides. Crystallin modifications and cleavage were quite dramatic in transgenic mouse lenses with mature cataract. Affected lenses showed capsule rupture at the posterior pole, with expulsion of the lens nucleus and degenerating fiber cells. Our study suggests that the cleaved APH fragment might exert catalytic activity against crystallins, resulting in the accumulation of distinct LMW peptides that promote protein aggregation in lenses expressing wt-APH. The APH transgenic model we developed will enable in vivo testing of the roles of crystallin fragments in protein aggregation. PMID:24554718

  1. The neutron silicon lens. An update of the thermal neutron lens results

    International Nuclear Information System (INIS)

    Johnson, M.W.; Daymond, M.R.

    2001-01-01

    This paper introduces the concept of the Neutron Silicon Lens (NSL) and provides and update on the experimental results achieved to date. The NSL design is a cylindrical neutron lens based on the use of multiple neutron mirrors supported and separated by silicon wafers. Such lenses would have many applications in both the primary and scattered beams on neutron instruments, and would lead to immediate improvements where the sample to be illuminated is small, as in high pressure or engineering strain scanning instruments. (author)

  2. Forensic Analysis of a Contact Lens in a Murder Case.

    Science.gov (United States)

    Zwerling, Charles S

    2016-03-01

    Contact lenses have had rare relevance in trials and/or investigations. After 5 years of burial, orbital remnants were retrieved from an exhumed body and subsequently identified as a key piece of material evidence in a murder trial. The exhumed case materials were evaluated under laboratory conditions and were determined to be contact lens remnants. Contact lens fracture and burial simulation studies were performed to provide additional corroboration of the physical findings of the exhumed contact lens remnants. This material evidence was instrumental in providing factual proof refuting the defendant's testimony in the murder trial. A brief history of contact lens composition and use is provided for understanding the methods and observational results. This forensic case study represents the first published documentation of a contact lens from an exhumed body being used in a murder investigation and establishes an operational procedure for future forensic contact lens examinations. © 2016 American Academy of Forensic Sciences.

  3. Lens regeneration in mice under the influence of vitamin A

    Indian Academy of Sciences (India)

    The effect of vitamin A has been studied on lens regeneration in young (7 days old) as well as adult mice. A longitudinal slit was made under local anesthesia in the cornea over the lens. The lens was extracted intact through the incision. Intraperitonial injection of vitamin A (0.05 ml of 30 IU/ml in young and 0.05 ml of 50 ...

  4. Subcontact Lens Bubble Formation under Low Atmospheric Pressure Conditions.

    Science.gov (United States)

    1986-08-01

    of subcontact lens bubble formation under scleral lenses at altitudes greater than 18,000 ft. Later, after many advances in contact lens fitting and...Reported here are the results of contact lens bubble studies with soft hydrophilic nd rigid gas-permeable lenses . Testing was accomplished in simulated...ccurred at altitudes greater than 20,000 ft. For soft contact lenses , bubble formation was etected in 22 of 92 eyes tested, and occurred at altitudes

  5. Analysis of phakic before intraocular lens implantation for fundus examination

    OpenAIRE

    Juan Chen; Zhong-Ping Chen; Rui-Ling Zhu

    2014-01-01

    AIM:To investigate the findings of the eyes which were examined preoperatively by three mirror contact lens before the implantation of implantable collamer lens(ICL). To analysis the retinal pathological changes and to explore the clinical analysis of early diagnosis and treatment in retinopathy on fundus examination before operation. METHODS:The retrospective case series study included 127 eyes of 64 patients who underwent phakic intraocular lens implantation were received the fundus examina...

  6. Haemophilus influenzae corneal ulcer in a therapeutic contact lens wearer.

    OpenAIRE

    Armstrong, J. R.; Cohen, K. L.; McCarthy, L. R.

    1984-01-01

    Haemophilus influenzae is an unusual corneal pathogen and an unusual cause of corneal ulcers in Western society. In previous reports corneal complications from H. influenzae have been secondary to a conjunctivitis. The first case of a primary H. influenzae corneal ulcer as a complication of therapeutic contact lens wear is presented. Since other uncommon bacteria have been reported as causes of contact lens related corneal ulcers, the bacteriology of contact lens related corneal ulcers is rev...

  7. Disposable contact lenses vs. contact lens maintenance for extended wear.

    Science.gov (United States)

    Josephson, J E; Caffery, B E; Campbell, I; Slomovic, A R

    1990-01-01

    We compared a disposable extended wear contact lens modality with conventional extended wear over a 6-week period. To do so, we refit 31 patients who had successfully worn conventional extended wear contact lenses for more than 1 year. One eye was fit with the AcuvueR disposable contact lens, and a new extended wear lens of the type the patient had been wearing was placed on the other eye. At weekly intervals the disposable lens was discarded and a new disposable lens inserted. At the same time, the conventional lens on the fellow eye was cleaned, disinfected, and reinserted. After 6 weeks the ocular response, subjective impressions, and condition of the lenses in the two eyes were compared. Both lenses were then cultured. Three subjects had to discontinue disposable lens wear because of adverse reactions to trapped cellular debris and corneal microcysts. Although the results were not statistically significant, the Acuvue lens appeared to perform better than or equal to the conventional lens in biomicroscopic observation, visual acuity measurement, and subjective patient preference. Eighty-seven percent of patients preferred to continue with the disposable system. There were no differences found in the type or degree of microbial contamination of the lenses.

  8. Further studies of contact lens motion during blinking.

    Science.gov (United States)

    Conway, H D; Knoll, H A

    1986-10-01

    Contact lens motion is felt to be of increasing importance in connection with debris elimination, particularly in extended wear lenses. Thus an improved analysis is made of a simple model for investigating the initial motion of a hard contact lens over the eye during blinking. It is shown that the assumption of constant tear film thickness is a reasonable one. This greatly simplifies the analysis. Various vertical force vs. time variations are considered and lens velocity/time graphs and maximum lens displacement calculated. These are in good agreement with the results of experiment.

  9. Geometry-invariant gradient refractive index lens: analytical ray tracing.

    Science.gov (United States)

    Bahrami, Mehdi; Goncharov, Alexander V

    2012-05-01

    A new class of gradient refractive index (GRIN) lens is introduced and analyzed. The interior iso-indicial contours mimic the external shape of the lens, which leads to an invariant geometry of the GRIN structure. The lens model employs a conventional surface representation using a coincoid of revolution with a higher-order aspheric term. This model has a unique feature, namely, it allows analytical paraxial ray tracing. The height and the angle of an arbitrary incident ray can be found inside the lens in a closed-form expression, which is used to calculate the main optical characteristics of the lens, including the optical power and third-order monochromatic aberration coefficients. Moreover, due to strong coupling of the external surface shape to the GRIN structure, the proposed GRIN lens is well suited for studying accommodation mechanism in the eye. To show the power of the model, several examples are given emphasizing the usefulness of the analytical solution. The presented geometry-invariant GRIN lens can be used for modeling and reconstructing the crystalline lens of the human eye and other types of eyes featuring a GRIN lens.

  10. Particle swarm optimization applied to automatic lens design

    Science.gov (United States)

    Qin, Hua

    2011-06-01

    This paper describes a novel application of Particle Swarm Optimization (PSO) technique to lens design. A mathematical model is constructed, and merit functions in an optical system are employed as fitness functions, which combined radiuses of curvature, thicknesses among lens surfaces and refractive indices regarding an optical system. By using this function, the aberration correction is carried out. A design example using PSO is given. Results show that PSO as optical design tools is practical and powerful, and this method is no longer dependent on the lens initial structure and can arbitrarily create search ranges of structural parameters of a lens system, which is an important step towards automatic design with artificial intelligence.

  11. [Phacoemulsification of subluxated lens with capsular tension ring implantation].

    Science.gov (United States)

    Dorecka, Mariola; Rokicki, Wojciech; Nita, Malgorzata; Krysik, Katarzyna; Nita, Ewa; Sikorska, Aleksandra; Romaniuk, Wanda

    2007-01-01

    To evaluate long term results of phacoemulsification with PC IOL and capsular tension ring (CTR) implantation in lens subluxation. The study comprised of 134 patients--146 eyes with subluxated lens. In all cases phacoemulsification with PC IOL and CTR implantation was performed. No intaroperative complications has occured. Postoperative complications included: inflammation in the anterior chamber in 3 eyes (2.1%), retinal detachment in 2 eyes (1.4%). In all cases there was no PC IOL decentration. (1) CTR facilitates phacoemulsification with PC IOL implantation in lens subluxation. (2) Phacoemulsification of subluxated lens with PC IOL and CTR implantation seems to be safe and effective procedure.

  12. 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.

  13. Spontaneous dislocation of lens bag with acrylic lens after uneventful cataract surgery ? unusual complication of cataract surgery

    OpenAIRE

    Shah, Mehul A.; Shah, Shreya M.; Mehta, Ruchir; Shah, Prerna

    2015-01-01

    Introduction: Spontaneous dislocation of intraocular lens with bag is rare.Methods: We report a case of a 56-year-old male who presented with spontaneous anterior dislocation of an in-the-bag intraocular lens 3 years after manual small incision cataract surgery. He had undergone manual small incision cataract surgery with foldable acrylic intraocular lens implantation, and 18 months after cataract surgery ND: YAG capsulotomy with uneventful post capsulotomy follow-up. 17 months after capsul...

  14. Mechanisms of Apoptosis on Human Lens Epithelium after Ultraviolet Light Exposure

    Science.gov (United States)

    Kim, Seong-Taeck

    2011-01-01

    Purpose The purpose of this study is to understand the mechanism of apoptosis occurring on a cultured human lens epithelial cell line after exposure to ultraviolet (UV) light. We intended to confirm the presence of cellular toxicity and apoptosis and to reveal the roles of p53, caspase 3 and NOXA in these processes. Methods Cells were irradiated with an ultraviolet lamp. Cellular toxicity was measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Hoechst staining and fluorescent anti-caspase 3 antibodies were used for apoptosis investigation. The quantities of p53, caspase 3, and NOXA were measured by Western blotting for to investigate the apoptosis pathway. Results Cellular toxicity on the human lens epithelium markedly increased with time after UV exposure. On Hoechst staining, we found that apoptosis also remarkably increased after exposure to ultraviolet light, compared with a control group. In the immunochemical study using anti-caspase 3 antibodies, active caspase 3 significantly increased after exposure to ultraviolet light. On Western blotting, p53 decreased, while caspase 3 and NOXA increased. Conclusions Exposure of cultured human lens epithelial cell lines to ultraviolet light induces apoptosis, which promotes the expression of NOXA and caspase 3 increases without increasing p53. This may suggest that UV induced apoptosis is caused by a p53-independent pathway in human lens epithelial cells. PMID:21655046

  15. LENS - the Low-Energy Neutrino Spectrometer

    International Nuclear Information System (INIS)

    Hahn, Richard L.

    2004-01-01

    Despite the recent successes of SNO and KamLAND, the only detectors sensitive to <1 MeV-neutrinos have been the radiochemical chlorine and gallium solar neutrino experiments. LENS is being developed to measure in real time the charge-current fluxes and energy spectra of the lowest energy solar neutrinos, from the pp and 7Be branches (91% and 7% of solar neutrinos). The detector medium will be a metal-loaded liquid scintillator (M-LS), with indium as the metal, which serves as the target for neutrino capture in the LS. 115In has 95.71% natural abundance and a 114.2-keV neutrino-capture Q-value. Neutrino capture in 115In produces a β particle and preferentially feeds an excited state of 115Sn that de-excites by delayed emission of two γ rays. This triple-coincidence 'tag' in time and space in principle is a very powerful tool to discriminate neutrino-capture events from backgrounds. The International LENS R and D Collaboration is working to develop an In-LS neutrino detector, with special properties, such as high indium content, high light yield, high optical transparency, long-term chemical stability, and good signal-to-background ratio. Success in preparing the In-LS has been achieved via the synthesis of In-carboxylates that are soluble in pseudocumene LS (note that these methods may also be applicable to the preparation of Gd-LS for reactor antineutrino experiments). Testing of some prototype LENS In-LS detector modules has begun recently at the Gran Sasso Laboratory

  16. [Corneal protection in contact lens users].

    Science.gov (United States)

    Egorova, G B; Mitichkina, T S; Shamsudinova, A R

    2014-01-01

    To evaluate the efficacy of corneoprotective agents (Corneregel and Solcoseryl) in contact lens users. A total of 66 long-term contact lens wearers with dry eye symptoms and varying degrees of corneal epitheliopathy were monitored. All patients used artificial tears, which, however, were not effective enough to suppress manifestations of corneal epitheliopathy and to release the associated discomfort. The therapy was supplemented with Corneregel. The following examination methods were applied: biomicroscopy with fluorescent staining, Norn test, Schirmer's test, advanced tearscopy with digital image analysis of the precorneal tear film lipid layer, corneal confocal microscopy. In all cases the assessment was performed prior to starting Corneregel and repeated in 7 days, 14 days and 1 month. Complete corneal re-epithelization and restoration of the most superficial layer of the epithelium were achieved within 7-14 days. In case of severe initial epitheliopathy the effect of Corneregel was not sufficient and epithelium defects remained. These patients additionally received Solcoseryl Eye Gel. After the treatment course the condition of corneal epithelium ameliorated and contact lens wearing comfort increased. A longer precorneal tear film break-up time indicated an increase of tear film stability. The total tear production did not change significantly. The moistening effect of Corneregel and low-viscosity artificial tears together with intensive regeneration of corneal epithelium enables structural recovery of the epithelial membrane and considerable improvement of the anterior corneal stroma. At the first stage of corneoprotective treatment it is appropriate to use preservative-free artificial tears of low and high viscosity. If the effect of tear substitutive therapy is unsatisfactory it is recommended to prescribe Corneregel and Solcoseryl. The regimen is to be adjusted individually.

  17. Lentil (Lens culinaris) Lipid Transfer Protein Len c 3: A Novel Legume Allergen

    NARCIS (Netherlands)

    Akkerdaas, J.; Finkina, E. I.; Balandin, S. V.; Santos Magadán, S.; Knulst, A.; Fernandez-Rivas, M.; Asero, R.; van Ree, R.; Ovchinnikova, T. V.

    2012-01-01

    Background: Lentils are increasingly consumed in many parts of the world. Two allergens, Len c 1 and 2, have been reported previously. Recently, peanut and green bean lipid transfer proteins (LTPs) have been identified as the first two members of an important group of allergens that might be

  18. Abnormal lens morphogenesis and ectopic lens formation in the absence of beta-catenin function

    Czech Academy of Sciences Publication Activity Database

    Krešlová, Jana; Machoň, Ondřej; Růžičková, Jana; Láchová, Jitka; Wawrousek, E.F.; Kemler, R.; Krauss, S.; Piatigorsky, J.; Kozmik, Zbyněk

    2007-01-01

    Roč. 45, č. 4 (2007), s. 157-168 ISSN 1526-954X R&D Projects: GA ČR GA204/04/1358 Institutional research plan: CEZ:AV0Z50520514 Keywords : Wnt * beta-catenin * gene * lens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.516, year: 2007

  19. Magnetic system of the Tevatron electron lens

    International Nuclear Information System (INIS)

    Bogdanov, I.; Kozub, S.; Pleskach, V.; Sytnik, V.; Tkachenko, L.; Zintchenko, S.; Zubko, V.; Kuznetsov, G.; Sery, A.; Shiltsev, V.

    2000-01-01

    The Tevatron Electron Lens (TEL) system consisting of seven SC and four conventional magnets has been developed and fabricated in IHEP for increase of luminosity in Tevatron. The SC cable tension and preload of SC coils are calculated. The chosen cable design and cooling of the SC magnets ensure sufficient temperature margin for operating of SC magnets and their safety during quench. The system of conventional and SC solenoids create necessary trajectory of magnetic field lines for the TEL electron beam motion. SC dipoles and warm correctors permit to carry out correction of the electron beam motion [ru

  20. Septic lens implantation syndrome in a cat.

    Science.gov (United States)

    Dalesandro, Nicole; Stiles, Jean; Miller, Margaret

    2011-09-01

    A 13-year-old female spayed domestic shorthair cat was presented initially for a change in the appearance of the left eye. On initial examination, a small penetrating wound was suspected as the cause for a corneal scar, an anterior cortical incipient cataract and mild iritis. The cat was not re-presented until 1 year later at which time ocular pain was marked. Severe anterior uveitis and glaucoma were diagnosed and the eye enucleated. Histopathology documented intralenticular coccoid bacteria and septic lens implantation syndrome. © 2011 American College of Veterinary Ophthalmologists.

  1. [Contact lens-associated Paecilomyces lilacinus keratitis].

    Science.gov (United States)

    Mihailovic, N; Alnawaiseh, M; Zumhagen, L; Eter, N

    2017-01-01

    We present the case of a 23-year-old otherwise healthy female patient with contact lens-associated Paecilomyces lilacinus keratitis. The clinical findings stabilized after initial local antimycotic and antibacterial treatment; however, in the further course of local therapy an extensive relapse occurred which required treatment by perforating keratoplasty à chaud due to a penetrating corneal ulcer. The patient responded well to subsequent treatment with systemic and local antimycotic medication. After a few months HLA-matched keratoplasty was performed. During the follow-up time of 14 months there were no signs of recurrence of the infection.

  2. Scleral lens for keratoconus: technology update

    OpenAIRE

    Rathi, Varsha; Taneja,Mukesh; Mandathara,Preeji; Sangwan,Virender; Dumpati,Srikanth

    2015-01-01

    Varsha M Rathi,1 Preeji S Mandathara,2 Mukesh Taneja,1 Srikanth Dumpati,1 Virender S Sangwan1 1L V Prasad Eye Institute, Hyderabad, India; 2School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia Abstract: Scleral lenses are large diameter lenses which rest over the sclera, unlike the conventional contact lenses which rest on the cornea. These lenses are fitted to not touch the cornea and there is a space created between the cornea and the lens. Th...

  3. Scientific performance assessments through a gender lens

    DEFF Research Database (Denmark)

    Nielsen, Mathias Wullum

    2018-01-01

    The focus on excellence and quality assurance in the academy has spawned a signifi cant increase in the use of bibliometric measures in performance assessments of individual researchers. This article investigates the organizational consequences of this development through a gender lens. Based....... They adhere to the prevailing ethos of the academic meritocracy by standardizing the criteria for organizational advancement and ensuring transparency and accountability in the selection process. While bibliometric tools in this sense may lead to the recruitment of scientists with a strong CV and track record...

  4. Polarization response of RHIC electron lens lattices

    Directory of Open Access Journals (Sweden)

    V. H. Ranjbar

    2016-10-01

    Full Text Available Depolarization response for a system of two orthogonal snakes at irrational tunes is studied in depth using lattice independent spin integration. In particular we consider the effect of overlapping spin resonances in this system, to understand the impact of phase, tune, relative location and threshold strengths of the spin resonances. These results are benchmarked and compared to two dimensional direct tracking results for the RHIC e-lens lattice and the standard lattice. Finally we consider the effect of longitudinal motion via chromatic scans using direct six dimensional lattice tracking.

  5. Candidate gravitational microlensing events for future direct lens imaging

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, C. B.; Gould, A.; Gaudi, B. S. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Park, H.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Sumi, T.; Koshimoto, N. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Bozza, V. [Department of Physics, University of Salerno, I-84084 Fisciano (Italy); Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Bond, I. A.; Ling, C. H. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland 0745 (New Zealand); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Fukui, A. [School of Chemical and Physical Sciences, Victoria University, Wellington 6140 (New Zealand); Collaboration: MOA Collaboration; OGLE Collaboration; μFUN Collaboration; RoboNet Collaboration; and others

    2014-10-10

    The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the source, and unrelated nearby stars with high-resolution images taken when the lens and source are spatially resolved. For typical ground-based adaptive optics (AO) or space-based observations, this requires either inordinately long time baselines or high relative proper motions. We provide a list of microlensing events toward the Galactic bulge with high relative lens-source proper motion that are therefore good candidates for constraining the lens mass with future high-resolution imaging. We investigate all events from 2004 to 2013 that display detectable finite-source effects, a feature that allows us to measure the proper motion. In total, we present 20 events with μ ≳ 8 mas yr{sup –1}. Of these, 14 were culled from previous analyses while 6 are new, including OGLE-2004-BLG-368, MOA-2005-BLG-36, OGLE-2012-BLG-0211, OGLE-2012-BLG-0456, MOA-2012-BLG-532, and MOA-2013-BLG-029. In ≲12 yr from the time of each event the lens and source of each event will be sufficiently separated for ground-based telescopes with AO systems or space telescopes to resolve each component and further characterize the lens system. Furthermore, for the most recent events, comparison of the lens flux estimates from images taken immediately to those estimated from images taken when the lens and source are resolved can be used to empirically check the robustness of the single-epoch method currently being used to estimate lens masses for many events.

  6. International survey of contact lens prescribing for extended wear.

    Science.gov (United States)

    Efron, Nathan; Morgan, Philip B; Woods, Craig A

    2012-02-01

    To determine the extent of extended wear (EW) contact lens prescribing worldwide and to characterize the associated demographics and fitting patterns. Up to 1000 survey forms were sent to contact lens fitters in up to 39 countries between January and March every year for five consecutive years (2006-2010). Practitioners were asked to record data relating to the first 10 contact lens fits or refits performed after receiving the survey form. Survey data collected since 1997 was also analyzed to assess EW fitting trends since that time. Details for lens modality were received for 107,094 rigid and soft lens fits of which 88,392 were for soft lens daily wear (DW) and 7470 were for soft lens EW. Overall, EW represents 7.8% of all soft lens fits, ranging from 0.6% in Malaysia to 27% Norway. Compared with DW fittings, EW fittings can be characterized as follows: older age (32.7 ± 13.6 vs. 29.4 ± 12.0 years for DW); males are over-represented; greater proportion of refits; 72% silicone hydrogel; higher proportion of presbyopia and spherical designs; and higher proportion of monthly lens replacement. Of those wearing EW lenses, 80% use multipurpose solutions, whereas 9% do not use any care system. Between 1997 and 1999, the rate of EW prescribing decreased from 5 to 1% of all soft lens fits; it increased to a peak of 12% in 2006, and settled back to 8% by 2010. EW prescribing has failed to break through the "glass ceiling" of 15% and is unlikely to become a mainstream lens wearing modality until the already low risks of ocular complications can be reduced to be equivalent to that for DW.

  7. L-type calcium channels play a critical role in maintaining lens transparency by regulating phosphorylation of aquaporin-0 and myosin light chain and expression of connexins.

    Directory of Open Access Journals (Sweden)

    Rupalatha Maddala

    Full Text Available Homeostasis of intracellular calcium is crucial for lens cytoarchitecture and transparency, however, the identity of specific channel proteins regulating calcium influx within the lens is not completely understood. Here we examined the expression and distribution profiles of L-type calcium channels (LTCCs and explored their role in morphological integrity and transparency of the mouse lens, using cDNA microarray, RT-PCR, immunoblot, pharmacological inhibitors and immunofluorescence analyses. The results revealed that Ca (V 1.2 and 1.3 channels are expressed and distributed in both the epithelium and cortical fiber cells in mouse lens. Inhibition of LTCCs with felodipine or nifedipine induces progressive cortical cataract formation with time, in association with decreased lens weight in ex-vivo mouse lenses. Histological analyses of felodipine treated lenses revealed extensive disorganization and swelling of cortical fiber cells resembling the phenotype reported for altered aquaporin-0 activity without detectable cytotoxic effects. Analysis of both soluble and membrane rich fractions from felodipine treated lenses by SDS-PAGE in conjunction with mass spectrometry and immunoblot analyses revealed decreases in β-B1-crystallin, Hsp-90, spectrin and filensin. Significantly, loss of transparency in the felodipine treated lenses was preceded by an increase in aquaporin-0 serine-235 phosphorylation and levels of connexin-50, together with decreases in myosin light chain phosphorylation and the levels of 14-3-3ε, a phosphoprotein-binding regulatory protein. Felodipine treatment led to a significant increase in gene expression of connexin-50 and 46 in the mouse lens. Additionally, felodipine inhibition of LTCCs in primary cultures of mouse lens epithelial cells resulted in decreased intracellular calcium, and decreased actin stress fibers and myosin light chain phosphorylation, without detectable cytotoxic response. Taken together, these observations

  8. Dose limits to the eye lens

    Energy Technology Data Exchange (ETDEWEB)

    Sion, N.

    2016-09-15

    Protecting the human body from the effects of ionizing radiation is essential to forestall stochastic effects and require placing limits on the effective dose. Dose limits on specific organs are also necessary to reduce the deterministic effects and tissue reactions. The standard for radiation protection was ISO 15382 (2002) which mainly dealt with beta radiation for nuclear power plant workers. Clearly an update is required to allow for new technology and the proliferative use of radiation in medical practices. There is a need for more explicit radiation monitoring to operators and staff. ICRP118 (International Commission on Radiological Protection), Ref. 1, evolved their recommendations to include eye lens doses as a follow on to their publication 103 and to focus on radiation exposures. It provides updated estimates of 'practical' threshold doses for tissue injury at the level of 1% incidence. This paper discusses the current status and the recommendation for a drastic reduction of the dose limit to the eye lens. (author)

  9. Scleral lens for keratoconus: technology update

    Directory of Open Access Journals (Sweden)

    Rathi VM

    2015-10-01

    Full Text Available Varsha M Rathi,1 Preeji S Mandathara,2 Mukesh Taneja,1 Srikanth Dumpati,1 Virender S Sangwan1 1L V Prasad Eye Institute, Hyderabad, India; 2School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia Abstract: Scleral lenses are large diameter lenses which rest over the sclera, unlike the conventional contact lenses which rest on the cornea. These lenses are fitted to not touch the cornea and there is a space created between the cornea and the lens. These lenses are inserted in the eyes after filling with sterile isotonic fluid. Generally, scleral contact lenses are used for high irregular astigmatism as seen in various corneal ectatic diseases such as keratoconus, pellucid marginal degeneration, or/and as liquid bandage in ocular surface disorders. In this article, we review the new developments, that have taken place over the years, in the field of scleral contact lenses as regard to new designs, materials, manufacturing technologies, and fitting strategies particularly for keratoconus. Keywords: keratoconus, scleral lens, technology update, PROSE

  10. Curiosity's Mars Hand Lens Imager (MAHLI) Investigation

    Science.gov (United States)

    Edgett, Kenneth S.; Yingst, R. Aileen; Ravine, Michael A.; Caplinger, Michael A.; Maki, Justin N.; Ghaemi, F. Tony; Schaffner, Jacob A.; Bell, James F.; Edwards, Laurence J.; Herkenhoff, Kenneth E.; Heydari, Ezat; Kah, Linda C.; Lemmon, Mark T.; Minitti, Michelle E.; Olson, Timothy S.; Parker, Timothy J.; Rowland, Scott K.; Schieber, Juergen; Sullivan, Robert J.; Sumner, Dawn Y.; Thomas, Peter C.; Jensen, Elsa H.; Simmonds, John J.; Sengstacken, Aaron J.; Wilson, Reg G.; Goetz, Walter

    2012-01-01

    The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ?5 km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ?2.1 cm to infinity. At the minimum working distance, image pixel scale is ?14 μm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI?s resolution is comparable at ?30 μm per pixel. Onboard capabilities include autofocus, auto-exposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage.

  11. An adjustable electron achromat for cathode lens microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tromp, R.M., E-mail: rtromp@us.ibm.com [IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Leiden Institute of Physics, Kamerlingh Onnes Laboratory, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

    2015-12-15

    Chromatic aberration correction in light optics began with the invention of a two-color-corrected achromatic crown/flint lens doublet by Chester Moore Hall in 1730. Such color correction is necessary because any single glass shows dispersion (i.e. its index of refraction changes with wavelength), which can be counteracted by combining different glasses with different dispersions. In cathode lens microscopes (such as Photo Electron Emission Microscopy – PEEM) we encounter a similar situation, where the chromatic aberration coefficient of the cathode lens shows strong dispersion, i.e. depends (non-linearly) on the energy with which the electrons leave the sample. Here I show how a cathode lens in combination with an electron mirror can be configured as an adjustable electron achromat. The lens/mirror combination can be corrected at two electron energies by balancing the settings of the electron mirror against the settings of the cathode lens. The achromat can be adjusted to deliver optimum performance, depending on the requirements of a specific experiment. Going beyond the achromat, an apochromat would improve resolution and transmission by a very significant margin. I discuss the requirements and outlook for such a system, which for now remains a wish waiting for fulfilment. - Highlights: • The properties of cathode objective lens plus electron mirror are discussed. • In analogy with light-optical achromats, cathode lens plus mirror can be configured as an electron achromat. • Unlike light optics, the electron achromat can be adjusted to best fulfill experimental requirements.

  12. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

    Zigman, S.

    1987-01-01

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  13. Introduction to designing information and organizations with a positive lens

    NARCIS (Netherlands)

    Avital, M.; Boland, R.J.; Lyytinen, K.

    2009-01-01

    The role and potential contribution of a positive lens to the design of systems and organizations is the focus of this introductory essay. The positive lens refers to a perspective in the social sciences that emphasizes the capacity of people and organizations to construct better work environments,

  14. Isofocusing and immunological investigations on cephalopod lens proteins

    NARCIS (Netherlands)

    Brahma, S.K.; Lancieri, M.

    1979-01-01

    Soluble lens proteins from Octopus vulgaris, Sepia officinalis, and Loligo vulgaris were analyzed by thin-layer isoelectric focusing and compared by various immunochemical methods using antibodies directed against total soluble lens protein antigens from the said three species. The results show

  15. RETINAL BREAKS IN VITRECTOMY FOR RETAINED LENS FRAGMENTS

    NARCIS (Netherlands)

    Tan, H. Stevie; Mura, Marco; Oberstein, Sarit Y. Lesnik; Bijl, Heico M.

    2012-01-01

    Purpose: To describe the incidence and outcome of retinal breaks in vitrectomy for retained lens fragments. Methods: This is a retrospective noncomparative interventional case series. Medical records of consecutive cases of vitrectomy for retained lens fragments over a period of 4 years were

  16. The NNEST lens non native english speakers in TESOL

    CERN Document Server

    Mahboob, Ahmar

    2010-01-01

    The NNEST Lens invites you to imagine how the field of TESOL and applied linguistics can develop if we use the multilingual, multicultural, and multinational perspectives of an NNEST lens to re-examine our assumptions, practices, and theories in the field

  17. The "Youth Lens": Analyzing Adolescence/ts in Literary Texts

    Science.gov (United States)

    Petrone, Robert; Sarigianides, Sophia Tatiana; Lewis, Mark A.

    2014-01-01

    Drawing from interdisciplinary scholarship that re-conceptualizes adolescence as a cultural construct, this article introduces a "Youth Lens." A "Youth Lens" comprises an approach to textual analysis that examines how ideas about adolescence and youth get formed, circulated, critiqued, and revised. Focused specifically on its…

  18. Optimized lens-sparing treatment of retinoblastoma with electron beams

    NARCIS (Netherlands)

    Steenbakkers, RJHM; Altschuler, MD; DAngio, GJ; Goldwein, JW; Kassaee, A

    1997-01-01

    Purpose: The ideal lens-sparing radiotherapy technique for retinoblastoma calls for 100% dose to the entire retina including the ora serrata and zero dose to the lens, Published techniques, most of which use photons, have not accomplished this ideal treatment. We describe here a technique that

  19. A Broadband Metasurface-Based Terahertz Flat-Lens Array

    KAUST Repository

    Wang, Qiu

    2015-02-12

    A metasurface-based terahertz flat-lens array is proposed, comprising C-shaped split-ring resonators exhibiting locally engineerable phase discontinuities. Possessing a high numerical aperture, the planar lens array is flexible, robust, and shows excellent focusing characteristics in a broadband terahertz frequency. It could be an important step towards the development of planar terahertz focusing devices for practical applications.

  20. Prevalence of corneal ulcer among contact lens wearers in Nigeria ...

    African Journals Online (AJOL)

    Corneal Ulceration has been described as the most serious complication of contact lens wear worldwide. The incidence of corneal ulceration in contact lens wearers in Nigeria was determined retrospectively. 1759 case notes of patients who had worn contact lenses for at least one year were obtained from eye clinics in ...

  1. Incidence of contact lens-associated microbial keratitis

    NARCIS (Netherlands)

    Cheng, K.H.; Leung, S.L.; Hoekman, J.W.; Beekhuis, W.H.; Mulder, P.G.H.; Geerards, A.J.M.; Kijlstra, A.

    1999-01-01

    Background. The incidence of contact-lens-associated microbial keratitis is uncertain and its related morbidity in the general population of contact-lens wearers is not known. We examined these issues in a prospective epidemiological study. Methods. We surveyed all practising ophthalmologists in the

  2. Failure of survival strategies in adaption of heavy metal environment in lens culinaris and phaseolus mungo

    International Nuclear Information System (INIS)

    Haider, S.; Azmat, R.

    2012-01-01

    Lead (Pb)-treated Lens culinaris and Phaseolus mungo seedlings leaves showed considerable reduction in the size with enhance proline and phenol contents while peroxidase and lignin activity was Pb/sup 2+/ dose dependent. The reduced leaves sizes of both seedlings were correlated with an increase in Pb/sup 2+/levels, and activities of peroxidase and lignin deposition in it. The intensification of activities of peroxidase and phenol in the Pb/sup 2+/ treated plants were accompanied by an increase in the biosynthesis of the lignin contents as their function is of scavenging ROS radical. A strong correlation (r/sup 2/=0.8570) was observed between Pb/sup 2+/ and lignin deposition in the Lens culinaris whereas it was non-significant in Phaseolus mungo (r/sup 2/=0.466). Increased in the lignin contents in the Lens culinaris as a chemical adaptation of the cell walls of various leaves tissues for endurance while decrease in the lignin contents in Phaseolus mungo at high dose of Pb/sup 2+/ may be attributed with the decline in the peroxidase activity. Investigations revealed that although plants adopt several biochemical strategies for their survival but toxicity of Pb/sup 2+/was significant due to which plant fails to continue in stay alive. (author)

  3. Patient acceptability of the Tecnis® multifocal intraocular lens

    Directory of Open Access Journals (Sweden)

    Sood P

    2011-03-01

    Full Text Available Priyanka Sood1, Maria A Woodward21Emory Eye Center, Atlanta, GA, USA; 2Kellogg Eye Center, Ann Arbor, MI, USAAbstract: Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients' desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anterior prolate IOL with a diffractive multifocal lens design. The design aims to minimize spherical aberration and improve range of focus. The purpose of this review is to assess patient acceptability of the Tecnis® multifocal intraocular lens.Keywords: Tecnis®, intraocular lens, multifocal, presbyopia 

  4. Composite modified Luneburg model of human eye lens.

    Science.gov (United States)

    Gómez-Correa, J E; Balderas-Mata, S E; Pierscionek, B K; Chávez-Cerda, S

    2015-09-01

    A new lens model based on the gradient-index Luneburg lens and composed of two oblate half spheroids of different curvatures is presented. The spherically symmetric Luneburg lens is modified to create continuous isoindicial contours and to incorporate curvatures that are similar to those found in a human lens. The imaging capabilities of the model and the changes in the gradient index profile are tested for five object distances, for a fixed geometry and for a fixed image distance. The central refractive index decreases with decreasing object distance. This indicates that in order to focus at the same image distance as is required in the eye, a decrease in refractive power is needed for rays from closer objects that meet the lens surface at steeper angles compared to rays from more distant objects. This ensures a highly focused image with no spherical aberration.

  5. Design of LED projector based on gradient-index lens

    Science.gov (United States)

    Qian, Liyong; Zhu, Xiangbing; Cui, Haitian; Wang, Yuanhang

    2018-01-01

    In this study, a new type of projector light path is designed to eliminate the deficits of existing projection systems, such as complex structure and low collection efficiency. Using a three-color LED array as the lighting source, by means of the special optical properties of a gradient-index lens, the complex structure of the traditional projector is simplified. Traditional components, such as the color wheel, relay lens, and mirror, become unnecessary. In this way, traditional problems, such as low utilization of light energy and loss of light energy, are solved. With the help of Zemax software, the projection lens is optimized. The optimized projection lens, LED, gradient-index lens, and digital micromirror device are imported into Tracepro. The ray tracing results show that both the utilization of light energy and the uniformity are improved significantly.

  6. Planar optical correlators integrated with binary optical lens.

    Science.gov (United States)

    Xu, Ping; Hong, Chunquan; Cheng, Guanxiao; Zhou, Liang; Sun, Zhilong

    2015-03-09

    Planar optical correlators (POCs) can achieve smaller volume of optical system and hence have important applications to identify dynamic targets in complex scenarios. POCs, however, generally have serious astigmatism and optical efficiency loss introduced by its refractive lens with a zigzag optical beam. To conquer the disadvantages of POCs, we propose a type of binary optical planar-integrated optical correlator. The correlator incorporates two pieces of reflective binary optical lens as Fourier transform lens and one spatial light modulator as a programmable filter. The off-axis aberrations commonly occurred in POCs can be corrected by using reflective binary optical lens instead of refractive lens. As a model of hybrid numerical-optical correlator using optoelectronic interface, the proposal is helpful to improve the integration and flexibility and robustness of POCs.

  7. Dielectrically embedded flat mesh lens for millimeter waves applications.

    Science.gov (United States)

    Pisano, Giampaolo; Ng, Ming Wah; Ozturk, Fahri; Maffei, Bruno; Haynes, Vic

    2013-04-10

    A flat lens based on subwavelength periodic metal meshes has been developed using photolithographic techniques. These mesh grids are stacked at specific distances and embedded in polypropylene. A code was developed to optimize more than 1000 transmission line circuits required to vary the device phase shift across the lens flat surface, mimicking the behavior of a classical lens. A W-band mesh-lens prototype was successfully manufactured and its RF performance characterized using a vector network analyzer coupled to corrugated horn antennas. Co-polarization far-field beam patterns were measured and compared with finite-element method models. The excellent agreement between data and simulations validated our designing tools and manufacturing procedures. This mesh lens is a low-loss, robust, light, and compact device that has many potential applications including millimeter wave quasi-optical systems for future cosmic microwave background polarization instruments.

  8. Antioxidative role of ocular melanin pigment in the model of lens induced uveitis.

    Science.gov (United States)

    Bilgihan, A; Bilgihan, M K; Akata, R F; Aricioğlu, A; Hasanreisoğlu, B

    1995-12-01

    Ocular melanin pigment has antioxidant effect against excess of dispersed light. To investigate whether it has a similar effect in ocular inflammations, we used albino and pigmented guinea pigs and measured retinal glutathione peroxidase activities and lipid peroxide levels (expressed as thiobarbituric acid reactive substances) in a model of lens induced uveitis. Although the increase in the levels of the retinal lipid peroxides were higher in the albino group (204%, p < 0.05), the decrease in the activities of glutathione peroxidase were higher in pigmented guinea pigs (26%, p < 0.005). The results of the study suggest that pigmentless animals are more sensitive to the ocular inflammations, and ocular melanin pigment may act as an endojen antioxidant in lens induced uveitis.

  9. The structural alteration and aggregation propensity of glycated lens crystallins in the presence of calcium: Importance of lens calcium homeostasis in development of diabetic cataracts

    Science.gov (United States)

    ZM, Sara Zafaranchi; Khoshaman, Kazem; Masoudi, Raheleh; Hemmateenejad, Bahram; Yousefi, Reza

    2017-01-01

    The imbalance of the calcium homeostasis in the lenticular tissues of diabetic patients is an important risk factor for development of cataract diseases. In the current study, the impact of elevated levels of calcium ions were investigated on structure and aggregation propensity of glycated lens crystallins using gel electrophoresis and spectroscopic assessments. The glycated proteins indicated significant resistance against calcium-induced structural insults and aggregation. While, glycated crystallins revealed an increased conformational stability; a slight instability was observed for these proteins upon interaction with calcium ions. Also, in the presence of calcium, the proteolytic pattern of native crystallins was altered and that of glycated protein counterparts remained almost unchanged. According to results of this study it is suggested that the structural alteration of lens crystallins upon glycation may significantly reduce their calcium buffering capacity in eye lenses. Therefore, under chronic hyperglycemia accumulation of this cataractogenic metal ion in the lenticular tissues may subsequently culminate in activation of different pathogenic pathways, leading to development of lens opacity and cataract diseases.

  10. Developing the Regulatory Utility of the Exposome: Mapping Exposures for Risk Assessment through Lifestage Exposome Snapshots (LEnS).

    Science.gov (United States)

    Shaffer, Rachel M; Smith, Marissa N; Faustman, Elaine M

    2017-08-07

    Exposome-related efforts aim to document the totality of human exposures across the lifecourse. This field has advanced rapidly in recent years but lacks practical application to risk assessment, particularly for children's health. Our objective was to apply the exposome to children's health risk assessment by introducing the concept of Lifestage Exposome Snapshots (LEnS). Case studies are presented to illustrate the value of the framework. The LEnS framework encourages organization of exposome studies based on windows of susceptibility for particular target organ systems. Such analyses will provide information regarding cumulative impacts during specific critical periods of the life course. A logical extension of this framework is that regulatory standards should analyze exposure information by target organ, rather than for a single chemical only or multiple chemicals grouped solely by mechanism of action. The LEnS concept is a practical refinement to the exposome that accounts for total exposures during particular windows of susceptibility in target organ systems. Application of the LEnS framework in risk assessment and regulation will improve protection of children's health by enhancing protection of sensitive developing organ systems that are critical for lifelong health and well-being. https://doi.org/10.1289/EHP1250.

  11. Force analysis of bacterial transmission from contact lens cases to corneas, with the contact lens as the intermediary

    NARCIS (Netherlands)

    Qu, Wen-wen; Hooymans, Johanna MM; de Vries, Jacob; van der Mei, Henderina; Busscher, Hendrik

    PURPOSE. To determine the probability of transmission of a Staphylococcus aureus strain from a contact lens case, to the contact lens (CL) surfaces, to the cornea, on the basis of bacterial adhesion forces measured by using atomic force microscopy (AFM). METHODS. Adhesion forces between S. aureus

  12. The Sloan Lens ACS Survey. I. A large spectroscopically selected sample of massive early-type lens galaxies

    NARCIS (Netherlands)

    Bolton, AS; Burles, S; Koopmans, LVE; Treu, T; Moustakas, LA

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple

  13. Bacterial transmission from lens storage cases to contact lenses - Effects of lens care solutions and silver impregnation of cases

    NARCIS (Netherlands)

    Vermeltfoort, Pit B. J.; Hooymans, Johanna M. M.; Busscher, Henk J.; van der Mei, Henny C.

    2008-01-01

    The killing efficacies of multipurpose lens care solutions on planktonic and biofilm bacteria grown in polypropylene contact lens storage cases with and without silver impregnation and effects on bacterial transmission from storage cases to silicone hydrogel contact lenses were investigated. For

  14. Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye

    Science.gov (United States)

    Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Iturbide-Jiménez, F.; Martínez-López, M.; Ramírez-Como, M.; Armengol-Cruz, V.; Vásquez-Báez, I.

    2014-09-01

    Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.

  15. Corrective Lens Use and Refractive Error Among United States Air Force Aircrew

    Science.gov (United States)

    2010-03-01

    among-USAF aircrew based on eyeglass orders processed through the Spectacle-Request-Transmission-System (SRTS).- Currently, 41% of active duty USAF...contact lens fittings, laser eye protection , and cor- neal refractive surgery (CRS) procedures. The Aerospace Ophthalmology Branch of the USAF School of...based on eyeglass orders filled by the Department of Defense (DoD) Optical Fabrication Enterprise as reported in the Spectacle Request Transmission

  16. Time lens assisted photonic sampling extraction

    Science.gov (United States)

    Petrillo, Keith Gordon

    Telecommunication bandwidth demands have dramatically increased in recent years due to Internet based services like cloud computing and storage, large file sharing, and video streaming. Additionally, sensing systems such as wideband radar, magnetic imaging resonance systems, and complex modulation formats to handle large data transfer in telecommunications require high speed, high resolution analog-to-digital converters (ADCs) to interpret the data. Accurately processing and acquiring the information at next generation data rates from these systems has become challenging for electronic systems. The largest contributors to the electronic bottleneck are bandwidth and timing jitter which limit speed and reduce accuracy. Optical systems have shown to have at least three orders of magnitude increase in bandwidth capabilities and state of the art mode locked lasers have reduced timing jitters into thousands of attoseconds. Such features have encouraged processing signals without the use of electronics or using photonics to assist electronics. All optical signal processing has allowed the processing of telecommunication line rates up to 1.28 Tb/s and high resolution analog-to-digital converters in the 10s of gigahertz. The major drawback to these optical systems is the high cost of the components. The application of all optical processing techniques such as a time lens and chirped processing can greatly reduce bandwidth and cost requirements of optical serial to parallel converters and push photonically assisted ADCs into the 100s of gigahertz. In this dissertation, the building blocks to a high speed photonically assisted ADC are demonstrated, each providing benefits to its own respective application. A serial to parallel converter using a continuously operating time lens as an optical Fourier processor is demonstrated to fully convert a 160-Gb/s optical time division multiplexed signal to 16 10-Gb/s channels with error free operation. Using chirped processing, an

  17. [Intraocular lens implantation with one loop haptic amputated: a new propose to the subluxation lens surgical treatment].

    Science.gov (United States)

    Ventura, Marcelo; Endriss, Daniela

    2010-01-01

    To evaluate the postoperative results of congenital lens subluxation corrected by a new technique. Retrospective chart review of 21 eyes of 13 patients with no traumatic lens subluxation who underwent surgery in Altino Ventura Foundation from April, 1999 to April, 2004. The mean age was 8.7 +/- 5.4 years old, and the mean follow-up period was 21.5 +/- 19.3 months. Patients underwent phacoaspiration, endocapsular ring and intraocular lens (IOL) implantation. The implanted IOL had one loop haptic excised and was supported above the ring, inside the capsular bag promoting intraocular lens centralization. Visual acuity improvement was observed in all cases. There was a significant reduction of the spherical equivalent and spherical component comparing the pre and postoperative refraction (psubluxation surgical treatment, promoting lens centralization and postoperative visual acuity improvement.

  18. Preparation, characterization and antimicrobial study of a hydrogel (soft contact lens) material impregnated with silver nanoparticles.

    Science.gov (United States)

    Fazly Bazzaz, Bibi Sedigheh; Khameneh, Bahman; Jalili-Behabadi, Mohammad-mehdi; Malaekeh-Nikouei, Bizhan; Mohajeri, Seyed Ahmad

    2014-06-01

    Contact lenses that incorporate antimicrobial properties may reduce the risk for microbial-associated adverse events for lens wearers. The aim of this study was to assess the antimicrobial effects of silver nanoparticles (NP) when impregnated in a hydrogel material. Hydrogel disks, used as a proxy for soft contact lenses, were prepared with silver NPs to add an antimicrobial effect to the polymer. Six groups of disks were created, each with a different concentration of silver NPs. The antimicrobial effect of the hydrogels against Pseudomonas aeruginosa (ATCC15442) and Staphylococcus aureus (ATCC6538) was evaluated at 6, 24, 48 and 72 h. Silver NP concentrations ranged from 20.71 to 98.06 μg/disk. All groups demonstrated excellent antibacterial effects against P. aeruginosa at each time point. After 6h all disks didn't exhibit desirable antibacterial activity against S. aureus; whereas except those with 20.71 μg silver NPs showed antibacterial activity at 24h and only the disks with 57.13 and 98.06 μg silver NPs showed antimicrobial activity at 48 and 72 h. The development of contact lenses made of a silver NP-impregnated hydrogel material may bring antimicrobial effects sufficient to decrease the risk of microbial-related adverse events for lens wearers. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  19. Perubahan Sosial Berbasis Tasawuf: Studi Kasus Fethullah Gülen Dan Gülen Movement

    Directory of Open Access Journals (Sweden)

    Sulaiman Sulaiman

    2016-06-01

    Full Text Available Abstract: This article aims at analyzing Fethullah Gülen and the Gülen Movement which have succeeded in performing social change based on the teaching of Sufism. He did Sufism creativity in order that Sufism teaching was able to respond the changes that occur in the modernlife. He believed that, only by reinterpretation and contextualization of Sufism, the spiritual dimension of Islam would be able to perform the transformation or social change among the Muslims. Therefore, by using Max Weber’s theory of social action, this paper will analyze three key teachings of Sufism of Gülen: ascetic (zuhd, inbisat (expansion, and hizmet. Based on the Weber's theory, Gülen occupied a very central and authoritative position: agent/actor, action and meaning. As a source of meaning and interpreter of meaning, the key concepts of Sufism were transformed by Gülen to the internal and external communities so that they had made a move to do social movements and humanity. For the followers of Gülen, the movement was called the Gülen Movement or the Hizmet Movement which was engaged in the fields of education, health care, humanitarian assistance, and the mass media. All forms of movement were entirely based on the spiritual values of Islam that had been formulated by Gülen. الملخص: يهدف هذا البحث إلى تحليل شخصية فتح الله غولن وحركته الذي تمكن من القيام بالتغيير الاجتماعي على أساس التعاليم الصوفية. إن فتح الله غولن قام بإحياء التصوف في صورته الجدّية والحيوية في حياة الإنسان المعاصر. ويعتقد أن إعادة التفسير لتعاليم التصوف مع مراعاة الواقع قادرة على التغيير الاجتماعي بين المسلمين. من أجل ذلك، أن استخدام نظرية ويبر، يمكن تحليل تعاليم التصوف الثلاثة

  20. High gradient lens for charged particle beam

    Science.gov (United States)

    Chen, Yu-Jiuan

    2014-04-29

    Methods and devices enable shaping of a charged particle beam. A dynamically adjustable electric lens includes a series of alternating a series of alternating layers of insulators and conductors with a hollow center. The series of alternating layers when stacked together form a high gradient insulator (HGI) tube to allow propagation of the charged particle beam through the hollow center of the HGI tube. A plurality of transmission lines are connected to a plurality of sections of the HGI tube, and one or more voltage sources are provided to supply an adjustable voltage value to each transmission line of the plurality of transmission lines. By changing the voltage values supplied to each section of the HGI tube, any desired electric field can be established across the HGI tube. This way various functionalities including focusing, defocusing, acceleration, deceleration, intensity modulation and others can be effectuated on a time varying basis.

  1. Accuracy of fish-eye lens models.

    Science.gov (United States)

    Hughes, Ciarán; Denny, Patrick; Jones, Edward; Glavin, Martin

    2010-06-10

    The majority of computer vision applications assumes that the camera adheres to the pinhole camera model. However, most optical systems will introduce undesirable effects. By far, the most evident of these effects is radial lensing, which is particularly noticeable in fish-eye camera systems, where the effect is relatively extreme. Several authors have developed models of fish-eye lenses that can be used to describe the fish-eye displacement. Our aim is to evaluate the accuracy of several of these models. Thus, we present a method by which the lens curve of a fish-eye camera can be extracted using well-founded assumptions and perspective methods. Several of the models from the literature are examined against this empirically derived curve.

  2. Scleral lens for keratoconus: technology update

    Science.gov (United States)

    Rathi, Varsha M; Mandathara, Preeji S; Taneja, Mukesh; Dumpati, Srikanth; Sangwan, Virender S

    2015-01-01

    Scleral lenses are large diameter lenses which rest over the sclera, unlike the conventional contact lenses which rest on the cornea. These lenses are fitted to not touch the cornea and there is a space created between the cornea and the lens. These lenses are inserted in the eyes after filling with sterile isotonic fluid. Generally, scleral contact lenses are used for high irregular astigmatism as seen in various corneal ectatic diseases such as keratoconus, pellucid marginal degeneration, or/and as liquid bandage in ocular surface disorders. In this article, we review the new developments, that have taken place over the years, in the field of scleral contact lenses as regard to new designs, materials, manufacturing technologies, and fitting strategies particularly for keratoconus. PMID:26604671

  3. 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....

  4. CERN through the lens of Peter Ginter

    CERN Multimedia

    2008-01-01

    This summer, passers-by along the Quai Wilson on the banks of Lake Geneva will be able to enjoy an unusual exhibition of photographs devoted to CERN and the LHC. Fifty images from the work of Peter Ginter, organized into themes, give strollers on the Quai Wilson a glimpse of the unique human and scientific adventure at CERN. An exhibition panel, showing a scientist against the background of ALICE’s huge red electromagnet.CERN will reach an important milestone in 2008 with the start-up of the LHC, opening a new window on our Universe for physicists around the world. To celebrate this event with the people who live around Lake Geneva and visitors to the area, CERN and the city of Geneva are jointly putting on the photography exhibition "CERN through the lens of Peter Ginter", which opens on 29 May. A group of some fifty images taken by the German photo...

  5. Hospitality as lens for migration studies

    DEFF Research Database (Denmark)

    Greve, Anni

    there are limits to its financial resources. What is more, the focus on claim-making and extended rights of the migrant produces a tendency for the language and practice of hospitality to ‘turn’ against the guest today, and notably the construction of the figure of guests who not only fail to fulfil their duties...... (welfare ‘parasites’) but even betray the host. Next, an enquiry of the concept of hospitality as possible lens for migration studies; it implies a twofold analyses with two levels, a macro level, to focus our attention to the modalities of hospitality given by the juridical status of the stranger and its...... influence on civil inclusion (Sassen 2007; Brenner 2011); and a meso level, to focus instead upon hospitality as an inter-subjective relationship between the host and the guest as a way to relate, as an experience and as an ethics (Derrida 2001). Finally the paper gives a short introduction into an on...

  6. Contrast sensitivity after refractive lens exchange with a multifocal diffractive aspheric intraocular lens

    Directory of Open Access Journals (Sweden)

    Teresa Ferrer-Blasco

    2013-04-01

    Full Text Available PURPOSE: To evaluate distance and near contrast sensitivity (CS under photopic and mesopic conditions before and after refractive lens exchange (RLE and implantation of the aspheric AcrySof®ReSTOR® (SN6AD3 model intraocular lens (IOL. METHODS:Seventy-four eyes of 37 patients after RLE underwent bilateral implantation with the aspheric AcrySof ReSTOR IOL. The patient sample was divided into myopic and hyperopic groups. Monocular uncorrected visual acuity at distance and near (UCVA and UCNVA, respectively and monocular best corrected visual acuity at distance and near (BCVA and BCNVA, respectively were measured before and 6 months postoperatively. Monocular CS function was measured at three different luminance levels (85, 5 and 2.5 cd/m² before and after RLE. Post-implantation results at 6 months were compared with those found before surgery. RESULTS: Our results revealed that patients in both groups obtained good UCVA and BCVA after RLE at distance and near vision in relation to pre-surgery values. No statistically significant differences were found between the values of CS pre and post-RLE at distance and near, at any lighting condition and spatial frequency (p>0.002. CONCLUSIONS: Refractive lens exchange with aspheric AcrySof ReSTOR IOL in myopic and hyperopic population provided good visual function and yield good distance and near CS under photopic and mesopic conditions.

  7. Aspherical Lens Design Using Genetic Algorithm for Reducing Aberrations in Multifocal Artificial Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Chih-Ta Yen

    2015-09-01

    Full Text Available A complex intraocular lens (IOL design involving numerous uncertain variables is proposed. We integrated a genetic algorithm (GA with the commercial optical design software of (CODE V to design a multifocal IOL for the human eye. We mainly used an aspherical lens in the initial state to the crystalline type; therefore, we used the internal human eye model in the software. The proposed optimized algorithm employs a GA method for optimally simulating the focusing function of the human eye; in this method, the thickness and curvature of the anterior lens and the posterior part of the IOL were varied. A comparison of the proposed GA-designed IOLs and those designed using a CODE V built-in optimal algorithm for 550 degrees myopia and 175 degrees astigmatism conditions of the human eye for pupil size 6 mm showed that the proposed IOL design improved the spot size of root mean square (RMS, tangential coma (TCO and modulation transfer function (MTF at a spatial frequency of 30 with a pupil size of 6 mm by approximately 17%, 43% and 35%, respectively. However, the worst performance of spherical aberration (SA was lower than 46%, because the optical design involves a tradeoff between all aberrations. Compared with the traditional CODE V built-in optimal scheme, the proposed IOL design can efficiently improve the critical parameters, namely TCO, RMS, and MTF.

  8. Concurrence of Danish dementia and cataract: insights from the interactions of dementia associated peptides with eye lens alpha-crystallin.

    Science.gov (United States)

    Surolia, Ira; Sinha, Sharmistha; Sarkar, Debi Prasad; Reddy, P Yadagiri; Reddy, G Bhanuprakash; Surolia, Avadhesha

    2008-08-13

    Familial Danish Dementia (FDD) is an autosomal disease, which is distinguished by gradual loss of vision, deafness, progressive ataxia and dementia. Cataract is the first manifestation of the disease. In this article, we demonstrate a specific correlation between the poisoning of the chaperone activity of the rat eye lens alpha-crystallins, loss of lens transparency in organ culture by the pathogenic form of the Danish dementia peptide, i.e. the reduced Danish dementia peptide (redADan peptide), by a combination of ex vivo, in vitro, biophysical and biochemical techniques. The interaction of redADan peptide and lens crystallins are very specific when compared with another chaperone, HSP-70, underscoring the specificity of the pathogenic form of Danish dementia peptide, redADan, for the early onset of cataract in this disease.

  9. Concurrence of Danish dementia and cataract: insights from the interactions of dementia associated peptides with eye lens alpha-crystallin.

    Directory of Open Access Journals (Sweden)

    Ira Surolia

    Full Text Available Familial Danish Dementia (FDD is an autosomal disease, which is distinguished by gradual loss of vision, deafness, progressive ataxia and dementia. Cataract is the first manifestation of the disease. In this article, we demonstrate a specific correlation between the poisoning of the chaperone activity of the rat eye lens alpha-crystallins, loss of lens transparency in organ culture by the pathogenic form of the Danish dementia peptide, i.e. the reduced Danish dementia peptide (redADan peptide, by a combination of ex vivo, in vitro, biophysical and biochemical techniques. The interaction of redADan peptide and lens crystallins are very specific when compared with another chaperone, HSP-70, underscoring the specificity of the pathogenic form of Danish dementia peptide, redADan, for the early onset of cataract in this disease.

  10. Lens dislocation has a possible relationship with laser iridotomy

    Directory of Open Access Journals (Sweden)

    Mutoh T

    2012-12-01

    Full Text Available Tetsuya Mutoh,1,2 Kevin F Barrette,2 Yukihiro Matsumoto,1 Makoto Chikuda11Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya City, Saitama, Japan; 2Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USAAbstract: We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 months following laser iridotomy. All patients were male and two eyes were complicated with acute primary angle closure glaucoma preoperatively. Case 1 showed bilateral lens dislocation, while cases 2 and 3 involved unilateral lens dislocation. Cases 2 and 3 showed lenses completely dislocated into the vitreous cavity. All cases needed lens removal and scleral fixation of intraocular lenses. Final visual acuity was 1.2 in all cases. We suspect that laser iridotomy may induce localized zonular dialysis that results in progressive zonular weakness, leading to lens dislocation.Keywords: lens dislocation, laser iridotomy, primary angle closure glaucoma

  11. 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.

  12. Surgical effect of traumatic lens dislocation with secondary glaucoma

    Directory of Open Access Journals (Sweden)

    Xiao-Dan Zhang

    2014-10-01

    Full Text Available AIM: To retrospectively evaluate the effect of lens extraction combined with vitrectomy to treat traumatic lens dislocation with secondary glaucoma.METHODS:Thirty-one eyes(31 casesof lens dislocation caused by blunt trauma with secondary glaucoma were treated respectively with cataract extraction combined with anterior vitrectomy, trabeculectomy and intraocular lens implantation. The visual acuity and pressure were observed 1wk, 1 and 3mo after operative. RESULTS:Thirty-one eyes were all complete the operation successfully, and 6 eyes were given combined trabeculectomy, 9 eyes were implanted anterior chamber intraocular lens implantation(IOLand 15 eyes were given posterior chamber suture fixation. Sixteen eyes were implanted in one-stage operation, while 8 eyes were implanted in two-stage operation. All intraocular pressure(IOPwere controlled to the normal level after operation and 23 eyes had visual acuity of more than 0.3.CONCLUSION:Lens extraction combined with vitrectomy is an effective method for treatment of lens dislocation with secondary glaucoma. In order to control the IOP and get well visual function, we should choose IOL implantation or trabeculectomy according to the patient's condition.

  13. Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia

    Science.gov (United States)

    Lanchares, Elena; Navarro, Rafael; Calvo, Begoña

    2012-01-01

    Purpose The modification of the mechanical properties of the human crystalline lens with age can be a major cause of presbyopia. Since these properties cannot be measured in vivo, numerical simulation can be used to estimate them. We propose an inverse method to determine age-dependent change in the material properties of the tissues composing the human crystalline lens. Methods A finite element model of a 30-year-old lens in the accommodated state was developed. The force necessary to achieve full accommodation in a 30-year-old lens of known external geometry was computed using this model. Two additional numerical models of the lens corresponding to the ages of 40 and 50 years were then built. Assuming that the accommodative force applied to the lens remains constant with age, the material properties of nucleus and cortex were estimated by inverse analysis. Results The zonular force necessary to reshape the model of a 30-year-old lens from the accommodated to the unaccommodated geometry was 0.078 newton (N). Both nucleus and cortex became stiffer with age. The stiffness of the nucleus increased with age at a higher rate than the cortex. Conclusions In agreement with the classical theory of Helmholtz, on which we based our model, our results indicate that a major cause of presbyopia is that both nucleus and cortex become stiffer with age; therefore, a constant value of the zonular forces with aging does not achieve full accommodation, that is, the accommodation capability decreases.

  14. Long-term changes in corneal endothelial morphology after discontinuation of low gas-permeable contact lens wear

    NARCIS (Netherlands)

    Odenthal, M. T. P.; Gan, I. M.; Oosting, J.; Kijlstra, A.; Beekhuis, W. H.

    2005-01-01

    Purpose: Low gas-permeable contact lens wear of polymethyl methacrylate or hydroxyethyl methacrylate material is known to cause morphologic abnormalities in the corneal endothelial cell layer. These tenses were widely prescribed and successfully worn until their use was actively discouraged in the

  15. Long-term changes in corneal endothelial morphology after discontinuation of low gas-permeable contact lens wear

    NARCIS (Netherlands)

    Odenthal, M.T.; Gan, I.M.; Oosting, J.; Kijlstra, A.; Beekhuis, W.H.

    2005-01-01

    Low gas-permeable contact lens wear of polymethyl methacrylate or hydroxyethyl methacrylate material is known to cause morphologic abnormalities in the corneal endothelial cell layer. These lenses were widely prescribed and successfully worn until their use was actively discouraged in the late 1980s

  16. Lens and cornea lesions of rats fed corn syrup and the protective effects of alpha lipoic acid.

    Science.gov (United States)

    Gunes, Alime; Ozmen, Ozlem; Saygın, Mustafa; Ascı, Halil; Tok, Levent; Tok, Ozlem; Dıncoglu, Dılnur

    2016-03-01

    To examine the pathological findings that occurred in the lens and cornea and biochemical findings in the lens of rats fed with corn syrup and the protective effects of alpha lipoic acid (ALA). Twenty-four rats were randomly divided into three groups. Group I served as the control group. Group II was used as the study group; the rats were treated with 30% corn sugar solution for 10 weeks. Group III was the treatment group. Corn syrup was given by the oral route to the rats during the study, and ALA (100 mg/kg) was added to the treatment 4 weeks after the study began. At the end of the experiment, central corneal thickness (CCT) was measured in all rats with an ultrasonic pachymeter. Then the right eyes of the rats were enucleated for histopathological examination of the cornea and lens. The left lenses were homogenized for biochemical analyses. The lenses of the rats treated with corn syrup revealed severe damage; many lens fibers appeared swollen and ruptured with large vacuoles near the lens epithelium. In addition, malondialdehyde (MDA) levels, a parameter of oxidative stress, increased but not significantly in Group II; however. ALA treatment decreased MDA levels significantly. Antioxidant enzyme and catalase (CAT) activities were significantly decreased in Group II, and ALA treatment increased these activities; however, the increase was not significant. Changes were observed in the cornea such as epithelial alterations, subepithelial vacuolizations, collagen fibers loss in the stromal layer, interruptions in the subepithelial basement membrane and central corneal thickening. Corn syrup can cause severe damage in rat lenses and corneas. However, ALA ameliorates the effect of corn syrup-related lesions on the cornea and lens.

  17. Means to flexibly attach lens frames to temple members

    Science.gov (United States)

    Smith, Harry D.

    1995-01-01

    The invention is a band hinge for flexibly connecting the temple member to the lens frame thereby preventing damage from inadvertent pressure or cyclic wear. A distinguishing feature of the invention is the use of a band hinge that holds together the temple member and the lens frame without the use of a pin or screw hinging mechanism. The invention allows for a high degree of freedom of movement for the temple member with respect to the lens frame which will prevent most forms of damages to the glasses from these types of events.

  18. The gravitational lens effect and its optical equivalents

    International Nuclear Information System (INIS)

    Freitas, L.R. de.

    1987-01-01

    This work presents the evolution of the use of the so called gravitational lens effect from a simple observational teste of the General Relativity theory to an instrument to measure cosmological parameters. A detailed analysis of how a gravitational ''lens'' deflects light without forming images is shown for the case of the deflector with spherical symmetry. In addition, the exact optical equivalent of a cylindrical gravitational lens, which forms true images, is proposed. Finally the problem of the formation of multiple images and the related astronomical observations is discussed. (author) [pt

  19. Characteristic of laser diode beam propagation through a collimating lens.

    Science.gov (United States)

    Xu, Qiang; Han, Yiping; Cui, Zhiwei

    2010-01-20

    A mathematical model of a laser diode beam propagating through a collimating lens is presented. Wave propagation beyond the paraxial approximation is studied. The phase delay of the laser diode wave in passing through the lens is analyzed in detail. The propagation optical field after the lens is obtained from the diffraction integral by the stationary phase method. The model is employed to predict the light intensity at various beam cross sections, and the computed intensity distributions are in a good agreement with the corresponding measurements.

  20. Electrostatic plasma lens for focusing negatively charged particle beams.

    Science.gov (United States)

    Goncharov, A A; Dobrovolskiy, A M; Dunets, S M; Litovko, I V; Gushenets, V I; Oks, E M

    2012-02-01

    We describe the current status of ongoing research and development of the electrostatic plasma lens for focusing and manipulating intense negatively charged particle beams, electrons, and negative ions. The physical principle of this kind of plasma lens is based on magnetic isolation electrons providing creation of a dynamical positive space charge cloud in shortly restricted volume propagating beam. Here, the new results of experimental investigations and computer simulations of wide-aperture, intense electron beam focusing by plasma lens with positive space charge cloud produced due to the cylindrical anode layer accelerator creating a positive ion stream towards an axis system is presented.

  1. Vortexlike Power Flow at the Interfaces of Metamaterial Lens

    Directory of Open Access Journals (Sweden)

    K. Fang

    2012-10-01

    Full Text Available The metamaterial lens with DPS/DNS/DPS structure has been realized by using the two-dimensional (2D isotropic transmission line approach. We studied the vortexlike power flow at the interfaces of metamaterial lens and validated by the finite-difference time-domain (FDTD simulator. The computational results showing its different conditions near DPS/DNS and other kinds of interfaces are obtained by CST STUDIO SUITE at different frequencies, and demonstrate the intuitionistic power location at the metamaterial lens interfaces.

  2. 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.

  3. 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

  4. Outcomes of Lensectomy in Hereditary Lens Subluxation

    Directory of Open Access Journals (Sweden)

    Mohammad-Hossein Dehghan

    2008-12-01

    Full Text Available

    PURPOSE: To evaluate the results of pars plana lensectomy in patients with hereditary lens subluxation. METHOD: Hospital records of patients with hereditary lens subluxation who had undergone pars plana lensectomy at Labbafinejad Medical Center, Tehran-Iran from 1996 to 2003 were reviewed. Patients with more than 6 months of follow up were included. Underlying disorders, best corrected visual acuity (BCVA before and after surgery, intraocular pressure (IOP, postoperative refraction and complications were evaluated. RESULTS: Overall, records of 87 eyes of 49 patients including 27 male and 22 female subjects were reviewed. Mean follow up duration was 20±18 months. Underlying disorders leading to lens subluxation included Marfan syndrome (79.5%, Weill-Marchesani syndrome (8.2%, simple ectopia lentis (8.2%, and homocystinuria (4.1%. The most common indication for surgery was non-correctable refractive error (92.1%. Mean BCVA was 1.13 LogMAR (20/250 preoperatively, which improved to 0.26 LogMAR (20/30-20/40 postoperatively (P < 0.001. BCVA better than 20/40 was achieved in 82.8% of cases after surgery. Angle-supported anterior chamber intraocular lens (ACIOL was implanted in

  5. Estimation of staff lens doses during interventional procedures. Comparing cardiology, neuroradiology and interventional radiology.

    Science.gov (United States)

    Vano, E; Sanchez, R M; Fernandez, J M

    2015-07-01

    The purpose of this article is to estimate lens doses using over apron active personal dosemeters in interventional catheterisation laboratories (cardiology IC, neuroradiology IN and radiology IR) and to investigate correlations between occupational lens doses and patient doses. Active electronic personal dosemeters placed over the lead apron were used on a sample of 204 IC procedures, 274 IN and 220 IR (all performed at the same university hospital). Patient dose values (kerma area product) were also recorded to evaluate correlations with occupational doses. Operators used the ceiling-suspended screen in most cases. The median and third quartile values of equivalent dose Hp(10) per procedure measured over the apron for IC, IN and IR resulted, respectively, in 21/67, 19/44 and 24/54 µSv. Patient dose values (median/third quartile) were 75/128, 83/176 and 61/159 Gy cm(2), respectively. The median ratios for dosemeters worn over the apron by operators (protected by the ceiling-suspended screen) and patient doses were 0.36; 0.21 and 0.46 µSv Gy(-1) cm(-2), respectively. With the conservative approach used (lens doses estimated from the over apron chest dosemeter) we came to the conclusion that more than 800 procedures y(-1) and per operator were necessary to reach the new lens dose limit for the three interventional specialties. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Taxon-specific zeta -crystallin in Japanese tree frog (Hyla japonica) lens.

    Science.gov (United States)

    Fujii, Y; Kimoto, H; Ishikawa, K; Watanabe, K; Yokota, Y; Nakai, N; Taketo, A

    2001-07-27

    The present study demonstrated that the 38-kDa protein, instead of rho-crystallin (36 kDa), is expressed taxon specifically in the lens of Japanese tree frog (Hyla japonica). The 38-kDa protein was distinguished from rho-crystallin expressed in the lenses of bullfrog (Rana catesbeiana) and European common frog (Rana temporaria) immunochemically. Although the N terminus of the 38-kDa protein was blocked, the analyses of partial amino acid sequences showed that the protein was zeta-crystallin. Analysis of cDNA sequence encoding zeta-crystallin of the tree frog lens demonstrated that the deduced protein consisted of 329 amino acids including initial methionine and having 62.2 and 62.9% identity with zeta-crystallin of camel and guinea pig lenses, respectively. The molecular mass of the deduced structure was calculated to be 35,564 Da. zeta-Crystallin of the tree frog lens exhibited the intrinsic enzymatic activity of quinone reductase (EC, NADPH:quinone oxidoreductase). The crystallin specifically catalyzed the reduction of 9,10-phenanthrenequinone (Km, 42 microm) using NADPH (Km, 60 microm) as a cofactor. The enzymatic activity was inhibited by dicumarol, anti-coagulant drug, with IC50 of 4 microm. On gel filtration chromatography, the crystallin was recovered as 150-kDa molecular mass complex, indicating that the crystallin was homotetramer consisting of 38-kDa subunits. The crystallin gene was expressed specifically in the lens. These results show that taxon-specific crystallins such as zeta- and rho-crystallins may be available for the biochemical discrimination of Hyla- and Rana groups among frogs.

  7. Dose estimation in the crystalline lens of industrial radiography personnel using Monte Carlo Method

    International Nuclear Information System (INIS)

    Lima, Alexandre Roza de

    2014-01-01

    The International Commission on Radiological Protection, ICRP, in its publication 103, reviewed recent epidemiological evidence and indicated that, for the eye lens, the absorbed dose threshold for induction of late detriment is around 0.5 Gy. On this basis, on April 21, 2011, the ICRP recommended changes to the occupational dose limit in planned exposure situations, reducing the eye lens equivalent dose limit from 150 mSv to 20 mSv per year, on average, during the period of 5 years, with exposure not to exceed 50 mSv in a single year. This paper presents the dose estimation to eye lens, H p (10), effective dose and doses to important organs in the body, received by industrial gamma radiography workers, during planned or accidental exposure situations. The computer program Visual Monte Carlo was used and two relevant scenarios were postulated. The first is a planned exposure situation scenario where the operator is directly exposed to radiation during the operation. 12 radiographic exposures per day for 250 days per year, which leads to an exposure of 36,000 seconds or 10 hours per year were considered. The simulation was carried out using the following parameters: a 192 Ir source with 1.0 TBq of activity, the source/operator distance varying from 5 m to 10 m at three different heights of 0.2 m, 1.0 m and 2.0 m. The eyes lens doses were estimated as being between 16.9 mSv/year and 66.9 mSv/year and for H p (10) the doses were between 17.7 mSv/year and 74.2 mSv/year. For the accidental exposure situation scenario, the same radionuclide and activity were used, but in this case the doses were calculated with and without a collimator. The heights above ground considered were 1.0 m, 1.5 m e 2.0 m, the source/operator distance was 40 cm and, the exposure time 74 seconds. The eyes lens doses, for 1.5 m, were 12.3 mGy and 0.28 mGy without and with a collimator, respectively. Three conclusions resulted from this work. The first was that the estimated doses show that the new

  8. The correct lens mount lightweighting design and thermal stress OPD analysis in Cassegrain telescope

    Science.gov (United States)

    Hsu, Ming-Ying; Chan, Chia-Yen; Lin, Wei-Cheng; Chang, Shenq-Tsong; Huang, Ting-Ming

    2013-09-01

    This study is trying to evaluate different lens barrel material, caused lens stress OPD (Optical Path Different) in different temperature condition. The Cassegrain telescope's correct lens assembly are including as correct lens, lens mount, spacer, mount barrel and retainer. The lens barrel initial design is made by invar, but system mass limit is need to lightweighting to meet requirement. Therefore, the lens barrel material is tried to replace to lower density material, such as aluminum and titanium alloy. Meanwhile, the aluminum or titanium alloy material properties CTE (Coefficient of Thermal Expansion) are larger then invar. Thus, the high CTE material will introduce larger thermal stress into the optical system in different temperature condition. This article is analysis the correct lens assembly thermal stress and optical performance in different lens mount material. From above conditions, using FEM (Finite Element Method) and optical software, simulation and optimization the lens mount to achieve system mass requirement.

  9. CFD model of a spinning pipe gas lens

    CSIR Research Space (South Africa)

    Snedden, Glen C

    2006-07-01

    Full Text Available Slides on: Spinning Pipe Gas Lens; Focal Length; Refractive Index; Gas Dynamics; Guess at the gas dynamics; Density Profile; Flow Profile; Rosby Waves; Rayleigh–Taylor Instabilities...

  10. Surface Fourier-transform lens using a metasurface

    International Nuclear Information System (INIS)

    Li, Yun Bo; Cai, Ben Geng; Cheng, Qiang; Cui, Tie Jun

    2015-01-01

    We propose a surface (or 2D) Fourier-transform lens using a gradient refractive index (GRIN) metasurface in the microwave band, which is composed of sub-wavelength quasi-periodical metallic patches on a grounded dielectric substrate. Such a metasurface supports the transverse magnetic (TM) modes of surface waves. To gradually change the size of textures, we obtain different surface refractive indices, which can be tailored to fit the required refractive-index profile of a surface Fourier-transform lens. According to the theory of spatial Fourier transformation, we make use of the proposed lens to realize surface plane-wave scanning under different feeding locations. The simulation and experimental results jointly confirm the validity of the surface Fourier-transform lens. The proposed method can also be extended to the terahertz frequency. (paper)

  11. Plasma lens experiments at the Final Focus Test Beam

    International Nuclear Information System (INIS)

    Barletta, B.; Chattopadhyay, S.; Chen, P.

    1993-04-01

    We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 x 10 10 , tunneling ionization of a gas target by an electron beam -- an effect which has never been observed before -- should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders

  12. Plasma lens experiments at the Final Focus Test Beam

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, B. [California Univ., Los Angeles, CA (United States)]|[Lawrence Berkeley Lab., CA (United States); Chattopadhyay, S. [Lawrence Berkeley Lab., CA (United States); Chen, P. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)] [and others

    1993-04-01

    We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 {times} 10{sup 10}, tunneling ionization of a gas target by an electron beam -- an effect which has never been observed before -- should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.

  13. Applications of thermal lens spectrometry in food industry and agriculture.

    NARCIS (Netherlands)

    Franko, M.; Bicanic, D.; Gibkes, J.; Bremer, M.; Akkermans, E.

    1996-01-01

    Applications of CO laser dual beam thermal lens spectrometry (TLS) for detection and characterization of fatty acids, aldehydes, pesticides, and herbicides in liquid samples are described. Also reported is the first TLS measurement of thermal conductivity for oleic acid.

  14. A 3D printed helical antenna with integrated lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2015-10-26

    A novel antenna configuration comprising a helical antenna with an integrated lens is demonstrated in this work. The antenna is manufactured by a unique combination of 3D printing of plastic material (ABS) and inkjet printing of silver nano-particle based metallic ink. The integration of lens enhances the gain by around 7 dB giving a peak gain of about 16.4 dBi at 9.4 GHz. The helical antenna operates in the end-fire mode and radiates a left-hand circularly polarized (LHCP) pattern. The 3-dB axial ratio (AR) bandwidth of the antenna with lens is 3.2 %. Due to integration of lens and fully printed processing, this antenna configuration offers high gain performance and requires low cost for manufacturing.

  15. Tunable Focus Liquid Lens with Radial-Patterned Electrode

    Directory of Open Access Journals (Sweden)

    Miao Xu

    2015-08-01

    Full Text Available A dielectric liquid lens is prepared based on our previous work. By optimizing the device structure, the liquid lens presents a converging focus with good resolution and changes its focal length over a broad range with a low driving voltage. For a liquid lens with ~2.3 mm diameter in the relaxed state, it can resolve ~40 lp/mm. The resolution does not degrade during focus change. Its focal length can be varied from ~12 to ~5 mm when the applied voltage is changed from 0 to 28 Vrms. The response time of one cycle is ~2.5 s. Our liquid lens, with a low driving voltage for a large dynamic range, has potential applications in imaging, biometrics, optoelectronic, and lab-on-chip devices.

  16. SIMION, Electrostatic Lens Analysis and Design

    International Nuclear Information System (INIS)

    Dahl, David A.

    2001-01-01

    1 - Description of program or function: SIMION is an electrostatic lens analysis and design program. In SIMION an electrostatic lens is defined as a two-dimensional electrostatic potential array containing both electrode and non-electrode points. The potential array is refined using over-relaxation methods allowing voltage contours and ion trajectories to be computed and plotted. Planar and cylindrical symmetry assumptions allow the two-dimensional fields to support three-dimensional ion trajectory calculations. In addition, the user has the option of writing simple programs which can among other actions control field scale factors, dynamically adjust electrodes, and define explicit three-dimensional field functions (e.g. a quadrupole) used in lieu of array fields in specified portions of the potential array. Magnetic fields can be specified for computing ion trajectories in many electrostatic and magnetic field environments. An interactive graphics interface that uses a high resolution color display and mouse allows the user to view electrodes, trajectories, and contours on the screen prior to plotting, and a memory zoom feature permits expansion of selected areas in the current view. The mouse can be operated to edit the potential array, initialize voltage gradients, or resize the potential array. 2 - Method of solution: SIMION is designed to model the electrostatic fields and forces created by a collection of shaped electrodes given certain symmetry assumptions. The electrostatic fields are modeled as boundary value problem solutions of a Laplace elliptical partial differential equation. A finite difference technique called dynamically self-adjusting over-relaxation is applied to the two-dimensional potential array of points representing electrode and non-electrode regions to obtain a best estimate of the voltages for those points within the array that depict non-electrode regions. A standard fourth-order Runge-Kutta method is used for numerical integration of

  17. A Randomized Controlled Trial of Tong Len Meditation Practice in Cancer Patients: Evaluation of a Distant Psychological Healing Effect.

    Science.gov (United States)

    Pagliaro, Gioacchino; Pandolfi, Paolo; Collina, Natalina; Frezza, Giovanni; Brandes, Alba; Galli, Margherita; Avventuroso, Federica Marzocchi; De Lisio, Sara; Musti, Muriel Assunta; Franceschi, Enrico; Esposti, Roberta Degli; Lombardo, Laura; Cavallo, Giovanna; Di Battista, Monica; Rimondini, Simonetta; Poggi, Rosalba; Susini, Cinzia; Renzi, Rina; Marconi, Linda

    2016-01-01

    Tong Len meditation is an important therapeutic tool in the Tibetan medicine, and it can be used for self-healing and/or to heal others. Currently, in the West, there is no scientific study concerning the efficacy of a Tong Len distant healing effect on psychological disorders in cancer patients. To evaluate a distant healing effect of Tong Len meditation on stress, anxiety, depression, fatigue, and self-perceived quality of life in cancer patients. These psychological objectives were chosen as a consequence of the limited scientific literature of present day. We performed a double-blind randomized controlled trial on 103 cancer patients with tumors. Overall, 12 meditators used Tong Len in aid of 52 patients randomly selected as experimental group, while the remaining 51 patients constituted the control group. Patients and meditators did not know each other. All patients completed profile of mood states (POMS) and European Quality of Life-5 dimensions (EQ-5D) questionnaires before treatment (T0), after two (T1) and three months of treatment (T2), and one month after treatment cessation (T3). With regard to the parameters related to depression, a statistically significant improvement (P = .003) was observed in the treatment group compared to controls. On the other hand, the vigor/activity parameter saw significant improvements in the control group (P = .009). Both groups exhibited significant improvements in the other factors assessed in the POMS and EQ-5D questionnaires. This study did not provide sufficient evidence supporting an efficacy of Tong Len meditation in distant psychological healing as compared to a control condition. The research highlighted some psychological improvements through Tong Len distant meditation in a group of patients unknown to meditators. Therefore, the enhancement detected in most parameters in both treatment and control groups raises interest on in-depth analysis and evaluation of distant meditation on cancer patients to mitigate

  18. Acanthamoeba corneal infection in a contact lens wearer.

    Science.gov (United States)

    Logar, J; Kraut, A

    1997-11-01

    Corneal infections cause by micro-organisms are the most serious complications of wearing contact lenses. The paper presents the first case of contact lens-associated keratitis caused by the protozoon Acanthamoeba sp. identified in Slovenia so far. The identification of Acanthamoeba as a cause of keratitis in a soft contact lens wearer alerted us to the fact that this health issue should be given more attention in the future.

  19. Analysis and synthesis of supershaped dielectric lens antennas

    OpenAIRE

    Bia, Pietro; Caratelli, Diego; Mescia, Luciano; Gielis, Johan

    2015-01-01

    Abstract: A novel class of supershaped dielectric lens antennas, whose geometry is described by the three-dimensional (3D) Gielis formula, is introduced and analysed. To this end, a hybrid modelling approach based on geometrical and physical optics is adopted in order to efficiently analyse the multiple wave reflections occurring within the lens and to evaluate the relevant impact on the radiation properties of the antenna under analysis. The developed modelling procedure has been validated b...

  20. Lens dislocation has a possible relationship with laser iridotomy

    OpenAIRE

    Mutoh, Tetsuya; Barrette, Kevin F; Matsumoto, Yukihiro; Chikuda, Makoto

    2012-01-01

    Tetsuya Mutoh,1,2 Kevin F Barrette,2 Yukihiro Matsumoto,1 Makoto Chikuda11Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya City, Saitama, Japan; 2Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USAAbstract: We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 mo...

  1. A bandage contact lens prevents extrusion of ocular contents.

    Science.gov (United States)

    Ramjiani, Vipul; Fearnley, Thomas; Tan, Jennifer

    2016-02-01

    A 76 year old male presents with a corneal perforation in a phthisical eye. Definitive treatment in the form of an evisceration was delayed by 38 days. During this period a bandage contact lens prevented extrusion of ocular contents through an enlarging corneal perforation. This case demonstrates that a bandage contact lens can be effective in the immediate management of large corneal perforations whilst awaiting urgent definitive treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Delayed diagnosis of homocystinuria presenting as bilateral congenital lens subluxation

    OpenAIRE

    Jelić-Vuković Marija; Matić Suzana; Barać Josip; Novinščak Tomislav; Belovari Mirna; Barić Hrvoje

    2017-01-01

    Introduction. Homocystinuria is an autosomal recessively inherited defect leading to hyperhomocysteinemia and associated with ocular manifestations, mainly myopia and ectopia lentis. Case outline. A 26-year-old male with secondary glaucoma due to bilateral lens subluxation was admitted to the Department of vitreoretinal surgery. Horizontal nystagmus, bilateral lens subluxation, and bilateral amblyopia were first discovered at the age of three years. Preoperative laboratory workup revealed ele...

  3. Detector LENS as a new tool for solar neutrino spectroscopy

    International Nuclear Information System (INIS)

    Kornoukhov, V.N.

    2001-01-01

    LENS detector is a low-threshold, electron-flavor specific detector for real time measurement of the solar neutrino spectrum at low energies. It is expected that 20 tons of Yb used as a neutrino target should give several hundred events per year. The basic method for implementation of the LENS detector is scintillator technique, namely a liquid scintillator doped (up to 10% in mass) with natural Yb

  4. Signal-enhancement reflective pulse oximeter with Fresnel lens

    Science.gov (United States)

    Chung, Shuang-Chao; Sun, Ching-Cherng

    2016-09-01

    In this paper, a new reflective pulse oximeter is proposed and demonstrated with implanting a Fresnel lens, which enhances the reflected signal. An optical simulation model incorporated with human skin characteristics is presented to evaluate the capability of the Fresnel lens. In addition, the distance between the light emitting diode and the photodiode is optimized. Compared with the other reflective oximeters, the reflected signal light detected by the photodiode is enhanced to more than 140%.

  5. Resistance force for intraocular lens insertion through lens cartridges and syringe-type injectors.

    Science.gov (United States)

    Usui, Masahiko; Tanaka, Takao

    2015-08-01

    To measure and compare the resistance force for intraocular lens (IOL) insertion using 5 syringe-type injector systems. Tokyo Medical University and laboratory in Kowa Co., Tokyo, Japan. Experimental study. Intraocular lenses were inserted into the lens capsular bag of porcine eyes after phacoemulsification using 5 implantation systems (Groups A, B, C, D, and E). For each system, the resistance force for IOL insertion to the lens capsular bag of porcine eyes was measured using an automated force gauge system. For control, the resistance force for IOL delivery into a plastic dish was measured. Changes in the resistance force and its curve and maximum value were evaluated. The mean total area under the curve (AUC) was compared. Data were statistically analyzed. For all groups, the mean resistance forces were 17.2, 6.3, 4.2, 20.7, and 2.3 newtons (N), respectively, in porcine eyes, and 14.4, 5.8, 4.5, 12.6, and 2.2 N in controls. The mean sizes of the total AUC were 43 371, 8465, 6771, 30 306, and 2334 pixels in porcine eyes and 40 940, 7080, 6876, 20 710, and 2215 pixels in controls; the correlation coefficients between the resistance forces and the sizes of the total area were 0.576, 0.113, 0.346, 0.726, and 0.933 in porcine eyes and 0.707, 0.557, 0.914, 0.951, and 0.893 in controls. Resistance force and its curve were clarified in 5 IOL implantation systems. Appropriate IOL and injector selection may be achieved after clarifying resistance force and its waveform during IOL insertion. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015. Published by Elsevier Inc.

  6. Cranial irradiation in acute leukemia: dose estimate in the lens

    International Nuclear Information System (INIS)

    Kline, R.W.; Gillin, M.T.; Kun, L.E.

    1979-01-01

    Cranial irradiation for subclinical arachnoid infiltration is standard treatment in childhood acute lymphocytic leukemia. The incidental dose received by the ocular lens is of potential importance since these children evidence a significant long-term survival rate. Comparison of the lens dose using 6MV and 4MV photon beams and a cobalt unit is presented in terms of ion chamber measurements in a water phantom and thermo-luminescent dosimetry (TLD) measurements in a head phantom. TLD measurements on patients treated for acute lymphocytic leukemia (ALL) are examined and used to estimate the dose to the lens. It is demonstrated that the dose to the lens depends strongly on the choice of field margin and on the daily patient set-up. However, using parallel opposed beams in a clinically determined optimal set-up, the dose to the lens is approximately 20 to 30% of the midline central axis dose. By angling the treatment head to eliminate the geometrical divergence of the beam, it is possible to reduce the lens dose to approximately 15% of the midline dose

  7. 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.

  8. Flat Lens Focusing Demonstrated With Left-Handed Metamaterial

    Science.gov (United States)

    Wilson, Jeffrey D.; Schwartz, Zachary D.; Chevalier, Christine T.; Downey, Alan N.; Vaden, Karl R.

    2004-01-01

    Left-handed metamaterials (LHM's) are a new media engineered to possess an effective negative index of refraction over a selected frequency range. This characteristic enables LHM's to exhibit physical properties never before observed. In particular, a negative index of refraction should cause electromagnetic radiation to refract or bend at a negative angle when entering an LHM, as shown in the figure above on the left. The figure on the right shows that this property could be used to bring radiation to a focus with a flat LHM lens. The advantage of a flat lens in comparison to a conventional curved lens is that the focal length could be varied simply by adjusting the distance between the lens and the electromagnetic wave source. In this in-house work, researchers at the NASA Glenn Research Center developed a computational model for LHM's with the three-dimensional electromagnetic commercial code Microwave Studio, constructed an LHM flat lens, and used it to experimentally demonstrate the reversed refraction and flat lens focusing of microwave radiation.

  9. Geometry-invariant GRIN lens: iso-dispersive contours

    Science.gov (United States)

    Bahrami, Mehdi; Goncharov, Alexander V.

    2012-01-01

    A dispersive model of a gradient refractive index (GRIN) lens is introduced based on the idea of iso-dispersive contours. These contours have constant Abbe number and their shape is related to iso-indicial contours of the monochromatic geometry-invariant GRIN lens (GIGL) model. The chromatic GIGL model predicts the dispersion throughout the GRIN structure by using the dispersion curves of the surface and the center of the lens. The analytical approach for paraxial ray tracing and the monochromatic aberration calculations used in the GIGL model is employed here to derive closed-form expressions for the axial and lateral color coefficients of the lens. Expressions for equivalent refractive index and the equivalent Abbe number of the homogeneous equivalent lens are also presented and new aspects of the chromatic aberration change due to aging are discussed. The key derivations and explanations of the GRIN lens optical properties are accompanied with numerical examples for the human and animal eye GRIN lenses. PMID:22808438

  10. The pupil can control an artificial lens intuitively.

    Science.gov (United States)

    Fliedner, Jan; Heine, Christian; Bretthauer, Georg; Wilhelm, Helmut

    2014-02-04

    After cataract surgery, the ability to accommodate is lost. For this reason, a mechatronic IOL is being developed at the moment: The Artificial Accommodation System. This device requires an easily measureable indicator of the distance of the observed object to determine the demand of accommodation. As the pupil constricts with near vision, pupil size might be such an indicator. Our research focused on whether the pupil can control an artificial lens. A study with 14 healthy subjects aged between 24 and 64 years was conducted. An artificial lens with variable refractive power was mounted in front of one eye. In this eye, natural accommodation was greatly reduced or absent due to presbyopia, pseudophakia, or iatrogenic cycloplegia. The lens' refractive power was changed in a computer-controlled manner depending on changes in the pupil diameter of the second eye, which could not see the fixation stimulus. The subject's task was to get a clear focused image of the target in different distances. The lens can be controlled by the pupil intuitively (P < 1.8 × 10(-18)). Without prior knowledge, 11/14 subjects passed the first trial, and 31/41 trials were successful. Only one subject was not able to control the lens at all. Most subjects comprehended instantly how to use the unfamiliar lens control to bring a target into focus. This study emphasizes the plasticity of the visual control system. Positioning accuracy was acceptable, but the control must be optimized to facilitate maintaining a defined refractive power.

  11. Adaptive neuro-fuzzy estimation of optimal lens system parameters

    Science.gov (United States)

    Petković, Dalibor; Pavlović, Nenad T.; Shamshirband, Shahaboddin; Mat Kiah, Miss Laiha; Badrul Anuar, Nor; Idna Idris, Mohd Yamani

    2014-04-01

    Due to the popularization of digital technology, the demand for high-quality digital products has become critical. The quantitative assessment of image quality is an important consideration in any type of imaging system. Therefore, developing a design that combines the requirements of good image quality is desirable. Lens system design represents a crucial factor for good image quality. Optimization procedure is the main part of the lens system design methodology. Lens system optimization is a complex non-linear optimization task, often with intricate physical constraints, for which there is no analytical solutions. Therefore lens system design provides ideal problems for intelligent optimization algorithms. There are many tools which can be used to measure optical performance. One very useful tool is the spot diagram. The spot diagram gives an indication of the image of a point object. In this paper, one optimization criterion for lens system, the spot size radius, is considered. This paper presents new lens optimization methods based on adaptive neuro-fuzzy inference strategy (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated.

  12. Innovative light collimator with afocal lens and total internal reflection lens for daylighting system.

    Science.gov (United States)

    Chen, Bo-Jian; Chen, Yin-Ti; Ullah, Irfan; Chou, Chun-Han; Chan, Kai-Cyuan; Lai, Yi-Lung; Lin, Chia-Ming; Chang, Cheng-Ming; Whang, Allen Jong-Woei

    2015-10-01

    This research presents a novel design of the collimator, which uses total internal reflection (TIR), convex, and concave lenses for the natural light illumination system (NLIS). The concept of the NLIS is to illuminate building interiors with natural light, which saves energy consumption. The TIR lens is used to collimate the light, and convex and concave lenses are used to converge the light to the required area. The results have shown that the efficiency in terms of achieving collimated light using the proposed collimator at the output of the light collector is better than that of a previous system without a collimator.

  13. Effects of gamma radiation on rabbit lens

    International Nuclear Information System (INIS)

    Ordahl, J.N.; Gorthy, W.C.

    1982-01-01

    Eyes of young New Zealand white rabbits were irradiated with 2000 rads of gamma radiation ( 60 Co) and the eyes removed at 2, 8, 16, and 30 days post-irradiation for electron microscopic analysis. Lenses were treated histochemically for acid phosphatase localization to examine the role of lysosomal enzymes in the early development of radiation cataracts. Intercellularly located acid phosphatase reaction product, noted in the epithelium and subjacent cortex, was more prevalent after irradiation, especially in central and transitional epithelial zones. In the central zone small vesicles typically were most numerous in areas of extensive intercellular reaction product. The occurrence of discrete packets of reaction product within the vesicles and the adjoining intercellular space, plus the resemblance of the peripheral vesicles to small Golgi vesicles also containing reaction product, suggested an exocytotic release of the enzyme. These appearances suggest that lysosomal hydrolases are released extracellularly by a secretory mechanism accelerated by radiation and that these hydrolases may play a role in both physiological and pathological functions of the lens. (author)

  14. Metasurface Enabled Wide-Angle Fourier Lens.

    Science.gov (United States)

    Liu, Wenwei; Li, Zhancheng; Cheng, Hua; Tang, Chengchun; Li, Junjie; Zhang, Shuang; Chen, Shuqi; Tian, Jianguo

    2018-04-19

    Fourier optics, the principle of using Fourier transformation to understand the functionalities of optical elements, lies at the heart of modern optics, and it has been widely applied to optical information processing, imaging, holography, etc. While a simple thin lens is capable of resolving Fourier components of an arbitrary optical wavefront, its operation is limited to near normal light incidence, i.e., the paraxial approximation, which puts a severe constraint on the resolvable Fourier domain. As a result, high-order Fourier components are lost, resulting in extinction of high-resolution information of an image. Other high numerical aperture Fourier lenses usually suffer from the bulky size and costly designs. Here, a dielectric metasurface consisting of high-aspect-ratio silicon waveguide array is demonstrated experimentally, which is capable of performing 1D Fourier transform for a large incident angle range and a broad operating bandwidth. Thus, the device significantly expands the operational Fourier space, benefitting from the large numerical aperture and negligible angular dispersion at large incident angles. The Fourier metasurface will not only facilitate efficient manipulation of spatial spectrum of free-space optical wavefront, but also be readily integrated into micro-optical platforms due to its compact size. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Exome Array Analysis of Nuclear Lens Opacity.

    Science.gov (United States)

    Loomis, Stephanie J; Klein, Alison P; Lee, Kristine E; Chen, Fei; Bomotti, Samantha; Truitt, Barbara; Iyengar, Sudha K; Klein, Ronald; Klein, Barbara E K; Duggal, Priya

    2018-06-01

    Nuclear cataract is the most common subtype of age-related cataract, the leading cause of blindness worldwide. It results from advanced nuclear sclerosis, or opacity in the center of the optic lens, and is affected by both genetic and environmental risk factors, including smoking. We sought to understand the genetic factors associated with nuclear sclerosis through interrogation of rare and low frequency coding variants using exome array data. We analyzed Illumina Human Exome Array data for 1,488 participants of European ancestry in the Beaver Dam Eye Study who were without cataract surgery for association with nuclear sclerosis grade, controlling for age and sex. We performed single-variant regression analysis for 32,138 variants with minor allele frequency (MAF) ≥0.003. In addition, gene-based analysis of 11,844 genes containing at least two variants with MAF nuclear sclerosis, the possible association with the RNF149 gene highlights a potential candidate gene for future studies that aim to understand the genetic architecture of nuclear sclerosis.

  16. Sutureless Intrascleral Fixated Intraocular Lens Implantation.

    Science.gov (United States)

    Karadag, Remzi; Celik, Haci Ugur; Bayramlar, Huseyin; Rapuano, Christopher J

    2016-08-01

    To review sutureless intrascleral intraocular lens (IOL) fixation methods. Review of published literature. Sutureless intrascleral IOL fixation methods are newer and have been developed to eliminate the suture-related complications of sutured scleral fixation methods such as suture-induced inflammation or infection and IOL dislocation or subluxation due to suture degradation or suture breakage. Sutureless intrascleral fixation methods aim for intrascleral haptic fixation to achieve stability of the IOL. Various methods of sutureless scleral fixation have been described. Using a needle, a blade, or a trochar, sclerostomies are created in all techniques for intraocular access. Some surgeons prefer to create scleral tunnels, whereas others use scleral flaps for scleral fixation of haptics. The stability of IOLs is attained by the scar tissue formed around the haptics. Short-term results of these new methods are acceptable; studies including more cases with longer follow-up are needed to determine their long-term success. [J Cataract Refract Surg. 2016;32(9):586-597.]. Copyright 2016, SLACK Incorporated.

  17. Harm reduction through a social justice lens.

    Science.gov (United States)

    Pauly, Bernadette

    2008-02-01

    People who are street involved such as those experiencing homelessness and drug use face multiple inequities in health and access to health care. Morbidity and mortality are significantly increased among those who are street involved. Incorporation of a harm reduction philosophy in health care has the potential to shift the moral context of health care delivery and enhance access to health care services. However, harm reduction with a primary focus on reducing the harms of drug use fails focus on the harms associated with the context of drug use such as homelessness, violence and poverty. Ethical analysis of the underlying values of harm reduction and examination of different conceptions of justice are discussed as a basis for action that addresses a broad range of harms associated with drug use. Theories of distributive justice that focus primarily on the distribution of material goods are limited as theoretical frameworks for addressing the root causes of harm associated with drug use. Social justice, reconceptualised and interpreted through a critical lens as described by Iris Marion Young, is presented as a promising alternative ethical framework. A critical reinterpretation of social justice leads to insights that can illuminate structural inequities that contribute to the harms associated with the context of drug use. Such an approach provides promise as means of informing policy that aims to reduce a broad range of harms associated with drug use such as homelessness and poverty.

  18. Phacoemulsification using iris hooks and scleral fixation of the intraocular lens in patients with secondary glaucoma associated with lens subluxation.

    Science.gov (United States)

    Ma, K T; Lee, H K; Seong, G J; Kim, C Y

    2008-09-01

    We described the techniques and results of phacoemulsification using iris hook and scleral fixation of intraocular lens (IOL) in patients with secondary glaucoma associated with lens subluxation. Eight eyes of seven patients with secondary glaucoma associated with lens dislocation, who had undergone the surgery, were retrospectively reviewed. At a mean of 23.5 months+/-13.6 (SD) after the surgery, the mean best-corrected visual acuity improved from 0.24+/-0.21 to 0.83+/-0.3, and mean intraocular pressure (IOP) was changed from 38.4+/-11.4 to 15.5+/-1.8 mmHg at the final examination. There were no vitreoretinal complications except cystoid macular oedema in one eye. The technique appears to be safe and effective in terms of visual rehabilitation and controlling IOP in patients with secondary glaucoma associated with lens subluxation.

  19. Multi-wavelength thermal-lens spectrometry for high-accuracy measurements of absorptivities and quantum yields of photodegradation of a hemoprotein–lipid complex

    Directory of Open Access Journals (Sweden)

    Kseniya Tishchenko

    2017-09-01

    Full Text Available Accurate measurements of absorptivities and quantum yields of biochemical species under various conditions are an important task of applied photonics and analytical chemistry. In this work, we provide a comparison of the capabilities of thermal-lens spectrometry to measure these parameters of various samples. Measurements of relevant model substances, biologically active substituted 2-thiohydantoins and their complexes of copper(I,II and heme proteins (forms of hemoglobin and cytochrome c, showed negligible differences in apparent molar absorptivities for thermal-lens spectrometry and optical-absorption (spectrophotometric data. The values for tabletop and microscale thermal-lens measurements under batch conditions differ insignificantly. The precision of measurements of molar absorptivities by thermal-lens spectrometry is no less than in the case of spectrophotometry or the precision is even higher in the cases of low absorptivities. For cardiolipin–cytochrome c-NO complex, the difference between absorptivity values calculated from thermal-lens data and acquired by spectrophotometry is significant due to complex photodegradation. The quantum yield of its photolysis reaction calculated from optical absorption and thermal-lens data altogether at two wavelengths for 0.4–360 s of the reaction, 0.46 ± 0.04, was estimated.

  20. Ethylene oxide-block-butylene oxide copolymer uptake by silicone hydrogel contact lens materials

    Energy Technology Data Exchange (ETDEWEB)

    Huo, Yuchen [Department of Materials Science and Engineering, University of Florida, Rhines Hall 100, Gainesville, FL 32611 (United States); Ketelson, Howard [Alcon Inc., Research and Development, Vision Care, 6201 South Freeway, Fort Worth, TX 76134 (United States); Perry, Scott S., E-mail: ssp@mse.ufl.edu [Department of Materials Science and Engineering, University of Florida, Rhines Hall 100, Gainesville, FL 32611 (United States)

    2013-05-15

    Four major types of silicone hydrogel contact lens material have been investigated following treatments in aqueous solutions containing poly(ethylene oxide) and poly(butylenes oxide) block copolymer (EO–BO). The extent of lens surface modification by EO–BO and the degree of bulk uptake were studied using X-ray photoelectron spectroscopy (XPS) and ultra-performance liquid chromatography (UPLC), respectively. The experimental results suggest that different interaction models exist for the lenses, highlighting the influence of both surface and bulk composition, which greatly differs between the lenses examined. Specifically, lenses with hydrophilic surface treatments, i.e., PureVision{sup ®} (balafilcon A) and O{sub 2}OPTIX (lotrafilcon B), demonstrated strong evidence of preferential surface adsorption within the near-surface region. In comparison, surface adsorption on ACUVUE{sup ®} Oasys{sup ®} (senofilcon A) and Biofinity{sup ®} (comfilcon A) was limited. As for bulk absorption, the amount of EO–BO uptake was the greatest for balafilcon A and comfilcon A, and least for lotrafilcon B. These findings confirm the presence of molecular concentration gradients within the silicone hydrogel lenses following exposure to EO–BO solutions, with the nature of such concentration gradients found to be lens-specific. Together, the results suggest opportunities for compositional modifications of lenses for improved performance via solution treatments containing surface-active agents.

  1. Ethylene oxide-block-butylene oxide copolymer uptake by silicone hydrogel contact lens materials

    Science.gov (United States)

    Huo, Yuchen; Ketelson, Howard; Perry, Scott S.

    2013-05-01

    Four major types of silicone hydrogel contact lens material have been investigated following treatments in aqueous solutions containing poly(ethylene oxide) and poly(butylenes oxide) block copolymer (EO-BO). The extent of lens surface modification by EO-BO and the degree of bulk uptake were studied using X-ray photoelectron spectroscopy (XPS) and ultra-performance liquid chromatography (UPLC), respectively. The experimental results suggest that different interaction models exist for the lenses, highlighting the influence of both surface and bulk composition, which greatly differs between the lenses examined. Specifically, lenses with hydrophilic surface treatments, i.e., PureVision® (balafilcon A) and O2OPTIX (lotrafilcon B), demonstrated strong evidence of preferential surface adsorption within the near-surface region. In comparison, surface adsorption on ACUVUE® Oasys® (senofilcon A) and Biofinity® (comfilcon A) was limited. As for bulk absorption, the amount of EO-BO uptake was the greatest for balafilcon A and comfilcon A, and least for lotrafilcon B. These findings confirm the presence of molecular concentration gradients within the silicone hydrogel lenses following exposure to EO-BO solutions, with the nature of such concentration gradients found to be lens-specific. Together, the results suggest opportunities for compositional modifications of lenses for improved performance via solution treatments containing surface-active agents.

  2. 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.

  3. [GA(2)LEN (Global Allergy and Asthma European Network): European network of excellence for asthma and allergic diseases].

    Science.gov (United States)

    Gjomarkaj, M; Pace, E; Canonica, G W; Bonini, S; Ricci, G; Burney, P; Zuberbier, T; Van Cauwenberge, P; Bousquet, J

    2009-12-01

    Allergic diseases represent some of the main health problems in Europe. These are increasing in prevalence, seriousness and social cost. The Global Allergy and Asthma European Network (GA(2)LEN), a network of excellence of the 6 degrees management program, was created in the 2005 with the aim to gather the European leader institutions of the research and clinical assistance fields, in order to guarantee the excellence and avoid the fragmentation of the energy spent in fighting allergy diseases in general. The GA(2)LEN has drawn a great advantage from the personal efforts of every single researcher who have proved their strong motivation in carrying on this "pan-European" model of collaboration. The network has been organized in order to increase the team work in scientific research projects in allergic and asthma disease field, making the GA(2)LEN the worldwide leader in this area. On these basis research projects have been carried on about which first data have been already published. The activities of the GA(2)LEN include in general the establishment of a lasting organization of the planning phase, the activity linked to every single project and to the improving on the existing projects, as well as the draft of new guidelines. This review reports the main achieved goals.

  4. Calculation of lens alignment errors using the ray transfer matrices for the lens assembly system with an autocollimator and a rotation stage

    Science.gov (United States)

    Chu, Jiyoung; Cho, Sungwhi; Joo, Won Don; Jang, Sangdon

    2017-08-01

    One of the most popular methods for high precision lens assembly of an optical system is using an autocollimator and a rotation stage. Some companies provide software for calculating the state of the lens along with their lens assembly systems, but the calculation algorithms used by the software are unknown. In this paper, we suggest a calculation method for lens alignment errors using ray transfer matrices. Alignment errors resulting from tilting and decentering of a lens element can be calculated from the tilts of the front and back surfaces of the lens. The tilt of each surface can be obtained from the position of the reticle image on the CCD camera of the autocollimator. Rays from a reticle of the autocollimator are reflected from the target surface of the lens, which rotates with the rotation stage, and are imaged on the CCD camera. To obtain a clear image, the distance between the autocollimator and the first lens surface should be adjusted according to the focusing lens of the autocollimator and the lens surfaces from the first to the target surface. Ray propagations for the autocollimator and the tilted lens surfaces can be expressed effectively by using ray transfer matrices and lens alignment errors can be derived from them. This method was compared with Zemax simulation for various lenses with spherical or flat surfaces and the error was less than a few percent.

  5. Electrophysiological evidence for temporal dynamics associated with attentional processing in the zoom lens paradigm

    Directory of Open Access Journals (Sweden)

    Qing Zhang

    2018-04-01

    Full Text Available Background Visuospatial processing requires wide distribution or narrow focusing of attention to certain regions in space. This mechanism is described by the zoom lens model and predicts an inverse correlation between the efficiency of processing and the size of the attentional scope. Little is known, however, about the exact timing of the effects of attentional scaling on visual searching and whether or not additional processing phases are involved in this process. Method Electroencephalographic recordings were made while participants performed a visual search task under different attentional scaling conditions. Two concentric circles of different sizes, presented to the participants at the center of a screen modulated the attentional scopes, and search arrays were distributed in the space areas indicated by these concentric circles. To ensure consistent eccentricity of the search arrays across different conditions, we limited our studies to the neural responses evoked by the search arrays distributed in the overlapping region of different attentional scopes. Results Consistent with the prediction of the zoom lens model, our behavioral data showed that reaction times for target discrimination of search arrays decreased and the associated error rates also significantly decreased, with narrowing the attentional scope. Results of the event-related potential analysis showed that the target-elicited amplitude of lateral occipital N1, rather than posterior P1, which reflects the earliest visuospatial attentional processing, was sensitive to changes in the scaling of visuospatial attention, indicating that the modulation of the effect of changes in the spatial scale of attention on visual processing occurred after the delay period of P1. The N1 generator exhibited higher activity as the attentional scope narrowed, reflecting more intensive processing resources within the attentional focus. In contrast to N1, the amplitude of N2pc increased with the

  6. Chitah: Strong-gravitational-lens hunter in imaging surveys

    Energy Technology Data Exchange (ETDEWEB)

    Chan, James H. H.; Suyu, Sherry H.; Chiueh, Tzihong; More, Anupreeta; Marshall, Philip J.; Coupon, Jean; Oguri, Masamune; Price, Paul

    2015-07-07

    Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. Current and upcoming imaging surveys will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we built a robot, Chitah, that hunts for lensed quasars by modeling the configuration of the multiple quasar images. Specifically, given an image of an object that might be a lensed quasar, Chitah first disentangles the light from the supposed lens galaxy and the light from the multiple quasar images based on color information. A simple rule is designed to categorize the given object as a potential four-image (quad) or two-image (double) lensed quasar system. The configuration of the identified quasar images is subsequently modeled to classify whether the object is a lensed quasar system. We test the performance of Chitah using simulated lens systems based on the Canada–France–Hawaii Telescope Legacy Survey. For bright quads with large image separations (with Einstein radius ${r}_{\\mathrm{ein}}\\gt 1\\buildrel{\\prime\\prime}\\over{.} 1$) simulated using Gaussian point-spread functions, a high true-positive rate (TPR) of $\\sim 90\\%$ and a low false-positive rate of $\\sim 3\\%$ show that this is a promising approach to search for new lens systems. We obtain high TPR for lens systems with ${r}_{\\mathrm{ein}}\\gtrsim 0\\buildrel{\\prime\\prime}\\over{.} 5$, so the performance of Chitah is set by the seeing. We further feed a known gravitational lens system, COSMOS 5921+0638, to Chitah, and demonstrate that Chitah is able to classify this real gravitational lens system successfully. Our newly built Chitah is omnivorous and can hunt in any ground-based imaging surveys.

  7. How Could Contact Lens Wearers Be at Risk of Acanthamoeba Infection? A Review

    Directory of Open Access Journals (Sweden)

    Youhanna W. Ibrahim

    2009-01-01

    Full Text Available Contact lens wear is highly influential on the incidence of ulcerative keratitis worldwide, particularly in developed countries. The association between Acanthamoeba keratitis and contact lens wear is firmly established; it may account for up to 95% of the reported cases. Before the popularisation of soft contact lens wear, Acanthamoeba keratitis was extremely rare. In 2000 it was estimated that the number of contact lens wearers worldwide was about 80 million, out of whom 33 million were in the United States and 90% of them wore hydrogel soft lenses. Contact lens-related problems depend on many factors, such as lens material, wearing modality, lens hygiene, type of lens-caring solution, the degree of compliance of the lens user with lens wear and care procedures, lens overwear, sleeping in lenses, rate of changing lenses, and lens case hygiene. This paper is a thorough review of the literature aiming to highlight the role of one of the main risk factors of infectious keratitis, contact lens wear, and also to show the responsibility of lens users in aggravating this risk.

  8. Novel fabrication technique of hybrid structure lens array for 3D images

    Science.gov (United States)

    Lee, Junsik; Kim, Junoh; Kim, Cheoljoong; Shin, Dooseub; Koo, Gyohyun; Won, Yong Hyub

    2016-03-01

    Tunable liquid lens arrays can produce three dimensional images by using electrowetting principle that alters surface tensions by applying voltage. This method has advantages of fast response time and low power consumption. However, it is challenging to fabricate a high fill factor liquid lens array and operate three dimensional images which demand high diopter. This study describes a hybrid structure lens array which has not only a liquid lens array but a solid lens array. A concave-shape lens array is unavoidable when using only the liquid lens array and some voltages are needed to make the lens flat. By placing the solid lens array on the liquid lens array, initial diopter can be positive. To fabricate the hybrid structure lens array, a conventional lithographic process in semiconductor manufacturing is needed. A negative photoresist SU-8 was used as chamber master molds. PDMS and UV adhesive replica molding are done sequentially. Two immiscible liquids, DI water and dodecane, are injected in the fabricated chamber, followed by sealing. The fabricated structure has a 20 by 20 pattern of cylindrical shaped circle array and the aperture size of each lens is 1mm. The thickness of the overall hybrid structure is about 2.8mm. Hybrid structure lens array has many advantages. Solid lens array has almost 100% fill factor and allow high efficiency. Diopter can be increased by more than 200 and negative diopter can be shifted to the positive region. This experiment showed several properties of the hybrid structure and demonstrated its superiority.

  9. The Lens Staring You in the Face

    Science.gov (United States)

    vachon, R. W.

    2012-12-01

    When you are embedded in the minutia of a science, you and your collaborators don't need to be convinced that there are benefits to investigating your precise science. You are intrinsically invested. In fact, we spend so much time around each other that we create our own language. So many acronyms that we come to take for granted and topic relevant words, like "fractionate", are not common parlance. This is the case with any specialization, but when it becomes second nature to communicate your work with these norms, transmission breaks down, people tune out, and some audiences become frustrated. Media can cushion this separation, but what do you do when you are the one in front of the camera, and clarity and impact of a concept rests on your shoulders? Just as writing a peer review paper is an acquired skill, so is communicating to the ones who pay many of our salaries, taxpayers. Over the past three years I have worked intimately with publishers, networks and university outreach programs to refine my approach to communicating scientific knowledge to particular audiences. The road has positioned me as interviewee, motivational speaker for science, technology, engineering and math (STEM) in middle and high schools, and educational video series host. Media has their own standards. Personality and enthusiasm may be just as important as the journal into which your findings were published. This presentation will emphasize the audience-adjustable tenants that have stood the test of time to result in effective video communication. Additionally, preparation for and execution of different roles in front of the lens will be discussed.Communicating concepts on video

  10. New trends in intraocular lens imaging

    Science.gov (United States)

    Millán, María S.; Alba-Bueno, Francisco; Vega, Fidel

    2011-08-01

    As a result of modern technological advances, cataract surgery can be seen as not only a rehabilitative operation, but a customized procedure to compensate for important sources of image degradation in the visual system of a patient, such as defocus and some aberrations. With the development of new materials, instruments and surgical techniques in ophthalmology, great progress has been achieved in the imaging capability of a pseudophakic eye implanted with an intraocular lens (IOL). From the very beginning, optical design has played an essential role in this progress. New IOL designs need, on the one hand, theoretical eye models able to predict optical imaging performance and on the other hand, testing methods, verification through in vitro and in vivo measurements, and clinical validation. The implant of an IOL requires a precise biometry of the eye, a prior calculation from physiological data, and an accurate position inside the eye. Otherwise, the effects of IOL calculation errors or misplacements degrade the image very quickly. The incorporation of wavefront aberrometry into clinical ophthalmology practice has motivated new designs of IOLs to compensate for high order aberrations in some extent. Thus, for instance, IOLs with an aspheric design have the potential to improve optical performance and contrast sensitivity by reducing the positive spherical aberration of human cornea. Monofocal IOLs cause a complete loss of accommodation that requires further correction for either distance or near vision. Multifocal IOLs address this limitation using the principle of simultaneous vision. Some multifocal IOLs include a diffractive zone that covers the aperture in part or totally. Reduced image contrast and undesired visual phenomena, such as halos and glare, have been associated to the performance of multifocal IOLs. Based on a different principle, accommodating IOLs rely on the effort of the ciliary body to increase the effective power of the optical system of the

  11. Development of a Laue lens for nuclear astrophysics

    International Nuclear Information System (INIS)

    Barriere, N.

    2008-04-01

    The Laue lenses we study focuses in the domain of 0.1-1 MeV thanks to Bragg diffraction in the volume of a large number of small crystal tiles. The focal length of a typical Laue lens system is of the order of 100 m. This requirement calls for two formation flying satellites maintaining lens and detector at the focal distance. The major breakthrough of Laue lenses is to decouple collecting area from detector area. Concentrating a signal from the large area of a Laue lens onto a small focal spot dramatically increases the signal over background ratio with respect to present technologies. Here is the reason for the long awaited leap in sensitivity. The objective of the present thesis was to improve the concept, finding viable technical solutions towards a future space mission. Two aspects of the lens development have been highlighted in this thesis: the first one is an analytical model of the lens that is used to calculate and improve the performance of a certain configuration, the second aspect concerns the search and the characterization of diffracting media of interest. The lens model developed relies on a fast semi-analytical simulation library, permitting to build several design- and optimisation-tools. For the configuration of a given lens, this code computes the resulting effective area and point spread function in a handful of seconds. The model helps finding lens configurations (mass, pack ratio of the lens rings,...) which are automatically refined to match with effective area and energy coverage constraints. These tools have been used to investigate various design aspects, such as the influence of focal length, size, mosaic spread, structure and materials of crystals, etc... The central evaluation criterion in the model is a figure of merit, based on the compactness of the focal spot and the intensity of the collected signal. The second part of this work addresses the actual search and characterization of crystals potentially interesting for Laue lenses

  12. 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.

  13. Athermal design and analysis of glass-plastic hybrid lens

    Science.gov (United States)

    Yang, Jian; Cen, Zhaofeng; Li, Xiaotong

    2018-01-01

    With the rapid development of security market, the glass-plastic hybrid lens has gradually become a choice for the special requirements like high imaging quality in a wide temperature range and low cost. The reduction of spherical aberration is achieved by using aspherical surface instead of increasing the number of lenses. Obviously, plastic aspherical lens plays a great role in the cost reduction. However, the hybrid lens has a priority issue, which is the large thermal coefficient of expansion of plastic, causing focus shift and seriously affecting the imaging quality, so the hybrid lens is highly sensitive to the change of temperature. To ensure the system operates normally in a wide temperature range, it is necessary to eliminate the influence of temperature on the hybrid lens system. A practical design method named the Athermal Material Map is summarized and verified by an athermal design example according to the design index. It includes the distribution of optical power and selection of glass or plastic. The design result shows that the optical system has excellent imaging quality at a wide temperature range from -20 ° to 70 °. The method of athermal design in this paper has generality which could apply to optical system with plastic aspherical surface.

  14. Performance evaluation of macro lens in digital close range photogrammetry

    Science.gov (United States)

    Yanagi, H.; Chikatsu, H.

    2009-08-01

    Recently, the documentation and visualization of various cultural heritages have been receiving attention, and a small Buddha such as less than 10 cm tall which was stored in the womb of Buddha is also included in cultural heritages. Zoom lenses are generally used to document these small objects and thus conserve the cultural heritage. However, there exist certain issues pertaining to the use of zoom lenses for such digital documentation. These issues include image sharpness and distortions that occur with changes in focal length setting, and in particular, the depth of field is issue from application standpoint such as documentation of the small cultural heritage. On the other hand, macro lenses can be used to capture sharp images of small objects from the view point of working distance, and its depth of field is related to the aperture of the camera. In order to evaluate the effectiveness of macro lenses in digital close range photogrammetry, macro lens and zoom lens were mounted on a digital single lens reflex camera (Canon EOS20D, 8.2 Mega pixels). This paper deals in a first part with comparative evaluations for both lenses with respect to their lens distortion, imaging mode, and calibration aspects. The results indicated that macro lenses were more suitable for digital close range photogrammetry. Calibration tests are performed to demonstrate the effectiveness and practicability of macro lens in close range photogrammetic applications.

  15. Lens array fabrication method with volume expansion property of PDMS

    Science.gov (United States)

    Jang, WonJae; Kim, Junoh; Lee, Muyoung; Lee, Jooho; Bang, Yousung; Won, Yong Hyub

    2016-03-01

    Conventionally, poly (dimethylsiloxane) lens array is fabricated by replica molding. In this paper, we describe simple method for fabricating lens array with expanding property of PDMS. The PDMS substrate is prepared by spin coating on cleaned glass. After spin coating PDMS, substrate is treated with O2 plasma to promote adhesion between PDMS substrate and photoresist pattern on it. Positive photoresist az-4330 and AZ 430K developer is used for patterning on PDMS. General photolithography process is used to patterning. Then patterned PDMS substrate is dipped to 1- Bromododecane bath. During this process, patterned photoresist work as a barrier and prevent blocked PDMS substrate from reaction with 1-Bromododecane. Unblocked part of PDMS directly react with 1-Bromododecane and results in expanded PDMS volume. The expansion of PDMS is depends on absorbed 1-Bromododecane volume, dipping time and ratio of block to open area. The focal length of lens array is controlled by those PDMS expansion factors. Scale of patterned photoresist determine a diameter of each lens. The expansion occurs symmetrically at center of unblocked PDMS and 1-Bromododecane interface. As a result, the PDMS lens array is achieved by this process.

  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. Determination of dideoxyosone precursors of AGEs in human lens proteins.

    Science.gov (United States)

    Linetsky, Mikhail; Kaid Johar, S R; Meltretter, Jasmin; Padmanabha, Smitha; Parmar, Trilok; Vasavada, Abhay R; Pischetsrieder, Monika; Nagaraj, Ram H

    2011-10-01

    Dideoxyosones (DDOs) are intermediates in the synthesis of advanced glycation endproducts (AGEs), such as pentosidine and glucosepane. Although the formation of pentosidine and glucosepane in the human lens has been firmly established, the formation of DDOs has not been demonstrated. The aim of this study was to develop a reliable method to detect DDOs in lens proteins. A specific DDO trapping agent, biotinyl-diaminobenzene (3,4-diamino-N-(3-[5-(2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanoyl]aminopropyl)benzamide) (BDAB) was added during in vitro protein glycation or during protein extraction from human lenses. In vitro glycated human lens protein showed strong reaction in monomeric and polymeric crosslinked proteins by Western blot and ELISA. Glycation of BSA in the presence of BDAB resulted in covalent binding of BDAB to the protein and inhibited pentosidine formation. Mass spectrometric analysis of lysozyme glycated in the presence of BDAB showed the presence of quinoxalines at lysine residues at positions K1, K33, K96, and K116. The ELISA results indicated that cataractous lens proteins contain significantly higher levels of DDO than non-cataractous lenses (101.9±67.8 vs. 31.7±19.5AU/mg protein, p<0.0001). This study provides first direct evidence of DDO presence in human tissue proteins and establishes that AGE crosslink synthesis in the human lens occurs via DDO intermediates. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Abnormal patterning analysis using actual lens and illumination source data

    Science.gov (United States)

    Hong, Jongkyun; Lee, Jeonkyu; Kang, Eunsuk; Yang, Hyunjo; Yim, Donggyu; Guerrero, James; Chung, Rob

    2005-05-01

    As the minimum feature size shrinks down, i.e. low K1 lithography regime, the tool"s lens aberration sensitivity and user defined illumination imperfection might play a major role in patterning error. Thus, the study of impact from lens aberration and illumination on patterning is required for good tool maintenance and yield improvement. For this purpose, we collected many cases of abnormal patterning result from production line and then simulated in terms of actual lens aberration and illumination source data. LITEL products of ISI(In-situ Interferometer) and SMI(Source Metrology Interferometer) were used for characterizing lens and illumination source. Moreover, the ACE(Analysis and Characteristic Engine) of LITEL development product was used as the simulator. In this work, deformation of pattern fidelity, for example, CD asymmetry in word line and metal contact layer, pattern bending in isolation layer and also decreasing process window in bit line layer will be discussed with experimental and simulation data. Finally, we are able to make a guideline for preventing abnormal phenomenon. From this study, we can understand which lens aberration terms and illumination imperfection take an effect of abnormal pattering result.

  19. Predicting scleral GP lens entrapped tear layer oxygen tensions.

    Science.gov (United States)

    Jaynes, Jared M; Edrington, Timothy B; Weissman, Barry A

    2015-02-01

    Over the past decade, utilization of scleral gas permeable (GP) contact lenses has steadily increased. Scleral GP lenses offer yet another option for patients suffering from visually debilitating corneal and tear conditions. Oxygen delivery to the cornea in the presence of a contact lens system continues to be a subject of interest, and scleral GP lenses are no exception. This paper utilizes an existing model based on simultaneous two lens systems (piggyback lenses) as a resistance to oxygen in series, and applies this model to scleral GP lens systems. Theoretical oxygen tensions are calculated for tear layers trapped beneath scleral contact lens systems and the anterior corneal surface with a simple single chamber corneal model using a computer software spreadsheet. Only the best case scenario for current scleral gas permeable lenses (thickness and Dk)/tear layer values allow sufficient tear layer oxygen tension (approximately 100 mmHg) to preclude corneal hypoxia. The results of the spreadsheet model suggest that clinicians would be prudent to prescribe scleral GP lenses manufactured in the highest Dk materials available and to fit without excessive corneal clearance to minimize anterior segment hypoxia. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  20. Delayed diagnosis of homocystinuria presenting as bilateral congenital lens subluxation

    Directory of Open Access Journals (Sweden)

    Jelić-Vuković Marija

    2017-01-01

    Full Text Available Introduction. Homocystinuria is an autosomal recessively inherited defect leading to hyperhomocysteinemia and associated with ocular manifestations, mainly myopia and ectopia lentis. Case outline. A 26-year-old male with secondary glaucoma due to bilateral lens subluxation was admitted to the Department of vitreoretinal surgery. Horizontal nystagmus, bilateral lens subluxation, and bilateral amblyopia were first discovered at the age of three years. Preoperative laboratory workup revealed elevated levels of homocysteine. Bilateral pars plana lensectomy and vitrectomy followed by a sulcus fixation of the intraocular lens (ALCON MA60 Acrysof IOL were performed. The patient was prescribed folic acid, methionine, and pyridoxine, and was urged to maintain a methionine-low diet. After a bilateral lensectomy and sulcus fixation of the intraocular lens and a methionine restriction therapy combined with vitamin B6, B9, and B12 supplementation, his condition improved greatly. Conclusion. In this report of a rare case we emphasize the importance of examining differential diagnoses of lens subluxation, since early intervention can prevent serious complications.

  1. Customer loyalty among daily disposable contact lens wearers.

    Science.gov (United States)

    Patel, Neelam I; Naroo, Shehzad A; Eperjesi, Frank; Rumney, Nicholas J

    2015-02-01

    Optometric practices offer contact lenses as cash sale items or as part of monthly payment plans. With the contact lens market becoming increasingly competitive, patients are opting to purchase lenses from supermarkets and Internet suppliers. Monthly payment plans are often implemented to improve loyalty. This study aimed to compare behavioural loyalty between monthly payment plan members and non-members. BBR Optometry Ltd offers a monthly payment plan (Eyelife™) to their contact lens wearers. A retrospective audit of 38 Eyelife™ members (mean±SD: 42.7±15.0 years) and 30 non-members (mean±SD: 40.8±16.7 years) was conducted. Revenue and profits generated, service uptake and product sales between the two groups were compared over a fixed period of 18 months. Eyelife™ members generated significantly higher professional fee revenue (Ployalty among contact lens wearers, particularly service uptake and volume of lens purchases. Additionally the greater professional fees generated, render monthly payment plans an attractive business model and practice builder. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  2. 3D Inkjet Printed Helical Antenna with Integrated Lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-08-30

    The gain of an antenna can be enhanced through the integration of a lens, although this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, through a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB, which provides a peak gain of about 12.9 dBi at 8.8 GHz. The 3-dB axial ratio (AR) bandwidth of the antenna with the lens is 5.5%. This work also reports the complete characterization of this new process in terms of minimum features sizes and achievable conductivities. Due to monolithic integration of the lens through a fully printed process, this antenna configuration offers high gain performance by using a low cost and rapid fabrication technique. © 2016 IEEE.

  3. Repertoire of free-living protozoa in contact lens solutions.

    Science.gov (United States)

    Bouchoucha, Ibtissem; Aziz, Aurore; Hoffart, Louis; Drancourt, Michel

    2016-10-29

    The repertoire of free-living protozoa in contact lens solutions is poorly known despite the fact that such protozoa may act as direct pathogens and may harbor intra-cellular pathogens. Between 2009 and 2014, the contact lens solutions collected from patients presenting at our Ophthalmology Department for clinically suspected keratitis, were cultured on non-nutrient agar examined by microscope for the presence of free-living protozoa. All protozoa were identified by 18S rRNA gene sequencing. A total of 20 of 233 (8.6 %) contact lens solution specimens collected from 16 patients were cultured. Acanthamoeba amoeba in 16 solutions (80 %) collected from 12 patients and Colpoda steini, Cercozoa sp., Protostelium sp. and a eukaryotic more closely related to Vermamoeba sp., were each isolated in one solution. Cercozoa sp., Colpoda sp., Protostelium sp. and Vermamoeba sp. are reported for the first time as contaminating contact lens solutions. The repertoire of protozoa in contact lens solutions is larger than previously known.

  4. Pigment dispersion syndrome associated with spontaneous subluxation of crystalline lens

    Directory of Open Access Journals (Sweden)

    Vikas Veerwal

    2017-01-01

    Full Text Available Pigment dispersion syndrome (PDS is an ocular condition characterized by a dispersion of iris pigment throughout the eye. This pigment is deposited in a characteristic manner on the corneal endothelium as Krukenberg's spindle, anterior surface of the iris, in the trabecular meshwork, on the lens and zonule and occasionally on the anterior hyaloid face. Even with deposition of pigment on zonular fibers, no zonular weakness, or zonular dehiscence has been reported in these cases. We report a unique case of PDS with bilateral spontaneous subluxation of crystalline lens. With characteristic findings of pigment distribution in both his eyes, the patient had concave iris configuration with heavily pigmented trabecular meshwork confirming the diagnosis of PDS. The patient had bilateral 180° temporal subluxation of crystalline lens in both his eyes. The usual cause of lens subluxation such as Marfan's Syndrome and Ehler's Danlos Syndrome was ruled out. The patient underwent right eye followed by left eye intracapsular cataract extraction with ab-interno technique with postoperative best-corrected visual acuity (BCVA of 6/9 in both eyes. Spontaneous subluxation of crystalline lens in isolated PDS is not known to occur and has been reported by means of this case. We recommend a thorough assessment of zonular status in all cases of PDS.

  5. Neural retina identity is specified by lens-derived BMP signals.

    Science.gov (United States)

    Pandit, Tanushree; Jidigam, Vijay K; Patthey, Cedric; Gunhaga, Lena

    2015-05-15

    The eye has served as a classical model to study cell specification and tissue induction for over a century. Nevertheless, the molecular mechanisms that regulate the induction and maintenance of eye-field cells, and the specification of neural retina cells are poorly understood. Moreover, within the developing anterior forebrain, how prospective eye and telencephalic cells are differentially specified is not well defined. In the present study, we have analyzed these issues by manipulating signaling pathways in intact chick embryo and explant assays. Our results provide evidence that at blastula stages, BMP signals inhibit the acquisition of eye-field character, but from neural tube/optic vesicle stages, BMP signals from the lens are crucial for the maintenance of eye-field character, inhibition of dorsal telencephalic cell identity and specification of neural retina cells. Subsequently, our results provide evidence that a Rax2-positive eye-field state is not sufficient for the progress to a neural retina identity, but requires BMP signals. In addition, our results argue against any essential role of Wnt or FGF signals during the specification of neural retina cells, but provide evidence that Wnt signals together with BMP activity are sufficient to induce cells of retinal pigment epithelial character. We conclude that BMP activity emanating from the lens ectoderm maintains eye-field identity, inhibits telencephalic character and induces neural retina cells. Our findings link the requirement of the lens ectoderm for neural retina specification with the molecular mechanism by which cells in the forebrain become specified as neural retina by BMP activity. © 2015. Published by The Company of Biologists Ltd.

  6. Neural retina identity is specified by lens-derived BMP signals

    Science.gov (United States)

    Pandit, Tanushree; Jidigam, Vijay K.; Patthey, Cedric; Gunhaga, Lena

    2015-01-01

    The eye has served as a classical model to study cell specification and tissue induction for over a century. Nevertheless, the molecular mechanisms that regulate the induction and maintenance of eye-field cells, and the specification of neural retina cells are poorly understood. Moreover, within the developing anterior forebrain, how prospective eye and telencephalic cells are differentially specified is not well defined. In the present study, we have analyzed these issues by manipulating signaling pathways in intact chick embryo and explant assays. Our results provide evidence that at blastula stages, BMP signals inhibit the acquisition of eye-field character, but from neural tube/optic vesicle stages, BMP signals from the lens are crucial for the maintenance of eye-field character, inhibition of dorsal telencephalic cell identity and specification of neural retina cells. Subsequently, our results provide evidence that a Rax2-positive eye-field state is not sufficient for the progress to a neural retina identity, but requires BMP signals. In addition, our results argue against any essential role of Wnt or FGF signals during the specification of neural retina cells, but provide evidence that Wnt signals together with BMP activity are sufficient to induce cells of retinal pigment epithelial character. We conclude that BMP activity emanating from the lens ectoderm maintains eye-field identity, inhibits telencephalic character and induces neural retina cells. Our findings link the requirement of the lens ectoderm for neural retina specification with the molecular mechanism by which cells in the forebrain become specified as neural retina by BMP activity. PMID:25968316

  7. 67P Through the Lens of Art

    Science.gov (United States)

    Smirnova, Ekaterina; ESA, The Open University, OSIRIS

    2016-10-01

    I am an artist, who is deeply inspired by science. Since the landing of the robotic probe Philae on the comet I have been working on an art project called 67P. Having a goal of discovering our place in the universe, I chose ESA's Rosetta mission as a successful example of such discovery. During the conference I'd like to expand the dialogue to include an artistic research of the comet 67P. I invite the participants to explore 67P through the lens of art and create inspirational reciprocity in between two spheres, creative and scientific. New ideas often originate when two vocabularies are smashed together. Via this path we perhaps will be able to get a new way of exploring the topic of cometary science.During the conference I'd like to present:- 67p artwork in the art section- poster outlining the major focuses of my projectArt project focuses:- 67P water:In the art studio I re-create water that is close in composition to the water on the comet, by enriching it with D2O. With this water I paint large scale paintings, based on the photographs by Rosetta (OSIRIS, Nav. Cam.).- spectroscopic data:Inspired by data from OSIRIS, I create an additional layer to my work using augmented reality to reveal a "hidden" from the view layer. I am making a parallel with the idea that some scientific information could be viewed only by using special instruments, in this case - instruments on board of Rosetta spacecraft, such as OSIRIS. You will be able to see a virtual layer on top of my paintings using a readily available instrument - your cellphone. Red, Green and Blue colors, of particular wavelength, will be introduced to the monochromatic paintings.- magnetometer readings:International music collaboration inspired by the "Singing comet" composition, based on the magnetometer data of 67P will be offered for any interested spectators.- 67P smell:In collaboration with The Open University, UK, postcards with a smell of the comet were created, introducing the chemical components of

  8. CTQ 327: A New Gravitational Lens

    Science.gov (United States)

    Morgan, N. D.; Gregg, M. D.; Wisotzki, L.; Becker, R.; Maza, J.; Schechter, P. L.; White, R. L.

    2003-08-01

    We present the second gravitationally lensed quasar discovered during the course of a Hubble Space Telescope Space Telescope Imaging Spectrograph snapshot survey for small-separation gravitational lenses. CTQ 327 is a double quasar with an image separation of 1.22" and a g-band flux ratio of roughly 5 to 1. Spectra reveal both components to be z=1.37 quasars, and the lensing galaxy is clearly visible after point-spread function subtraction of the two quasar components. The light profile of the lensing galaxy is well modeled by an r1/4 law, indicative of an early-type elliptical galaxy. An estimate of the lens galaxy redshift is z~0.4-0.6, based on the Faber-Jackson relationship and photometric considerations, although values outside this range are still consistent with the present data. Resolved spectra of the two quasars show similar, but not identical, continuum and emission-line features: component A exhibits weaker emission lines with respect to the continuum than does component B, and there is evidence of intrinsic differences in the emission-line profiles between the two components. Optical monitoring of the quasar pair also shows a change in the g-band flux ratio of 0.14 mag over a 3 month period. These spectral and photometric differences may be due to microlensing fluctuations from stars in the lensing galaxy, intrinsic quasar variability coupled with the system's differential time delay, or some combination of the two. The observed variability makes CTQ 327 an attractive target for future flux monitoring, aimed at time-delay or microlensing studies. Based on observations obtained with the NASA/ESA Hubble Space Telescope, the W. M. Keck Observatory, and the Magellan Consortium's Walter Baade Telescope. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-26555. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of

  9. Refractive lens exchange and piggyback intraocular lens implantation in nanophthalmos: Visual and structural outcomes.

    Science.gov (United States)

    Mohebbi, Masoomeh; Fallah-Tafti, Mohammad-Reza; Fadakar, Kaveh; Katoozpour, Ramon; Mohammadi, Seyed-Farzad; Fallah-Tafti, Zahra; Khorami, Azita

    2017-09-01

    To evaluate the best piggyback intraocular lens (IOL) implantation method and the outcomes in nanophthalmos eyes and to define the postoperative structural changes. Farabi Eye Hospital, Tehran, Iran. Prospective case series. Candidates for refractive surgery who were nanophthalmic were recruited. Patients had refractive lens exchange followed by implantation of both IOLs in the bag or 1 IOL in the bag and 1 IOL in the sulcus. The baseline and follow-up visual acuity, refractive status, and structural Scheimpflug imaging were evaluated. Ultrasound biomicroscopy (UBM) was performed 6 months postoperatively. The study comprised 9 nanophthalmic patients (18 eyes) with a mean preoperative uncorrected distance visual acuity (UDVA) of 1.53 logarithm of the minimum angle of resolution (logMAR) ± 0.3 (SD), mean corrected distance visual acuity (CDVA) of 0.34 ± 0.2 logMAR, and mean spherical equivalent (SE) of +13.55 ± 4.0 diopters (D). The mean postoperative UDVA improved from baseline. There was no significant difference in the mean UDVA and CDVA between the 2 IOL groups. Postoperatively, both groups had a significant improvement in SE, a significant rise in anterior chamber depth and angle, and similar UBM measurements. Piggyback IOL implantation was an effective refractive procedure in nanophthalmic eyes. Both implantation methods resulted in similar outcomes; however, the small number of patients in each group made it less likely that possible differences would be found. The increase in angle values might help prevent the development of closed-angle glaucoma. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. The effects of oral Ginkgo biloba supplementation on radiation-induced oxidative injury in the lens of rat.

    Science.gov (United States)

    Okumus, Seydi; Taysi, Seyithan; Orkmez, Mustafa; Saricicek, Edibe; Demir, Elif; Adli, Mustafa; Al, Behcet

    2011-04-01

    The aim of this study was to evaluate the antioxidant role of Ginkgo biloba (GB) against radiation-induced cataract in the rat lens after total cranial irradiation with a single 5 Gray (Gy) dose of gamma irradiation. Twenty-four Sprague-Dawley rats were used for the experiment. The rats were randomly divided into three equal groups. Group 1 did not receive GB or irradiation (control group) but received 1-ml saline orally plus sham-irradiation. Group 2 received total cranium 5 Gy of gamma irradiation as a single dose (IR group) plus 1-ml saline orally. Group 3 received total cranium irradiation plus 40 mg/kg/day GBE (IR plus GBE group). Biochemical parameters measured in murine lenses were carried out using spectrophotometric techniques. Lens total (enzymatic plus non-enzymatic) superoxide scavenger activity (TSSA), non-enzymatic superoxide scavenger activity (NSSA), glutathione reductase (GRD), and glutathione-S- transferase (GST) activities significantly increased in the IR plus GBE groups when compared with the IR group. However, TSSA, GRD and GST activities were significantly lower in the IR group when compared with the control group. Lens xanthine oxidase (XO) activity in the IR group significantly increased compared to that of both the control and IR plus GBE groups. GBE has clear antioxidant properties and is likely to be a valuable drug for protection against gamma-irradiation and/or be used as an antioxidant against oxidative stress.

  11. An integral-field spectroscopic strong lens survey

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, Adam S [Harvard-Smithsonian Center for Astrophysics, 60 Garden St. MS-20, Cambridge, MA 02138 (United States); Burles, Scott [Department of Physics and Kavli Institute, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States)

    2007-12-15

    We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS and nearly Poisson-limited sky subtraction.

  12. Flat acoustic lens by acoustic grating with curled slits

    KAUST Repository

    Peng, Pai

    2014-10-01

    We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry-Perot resonance.

  13. Investigation into photostability of soybean oils by thermal lens spectroscopy

    Science.gov (United States)

    Savi, E. L.; Malacarne, L. C.; Baesso, M. L.; Pintro, P. T. M.; Croge, C.; Shen, J.; Astrath, N. G. C.

    2015-06-01

    Assessment of photochemical stability is essential for evaluating quality and the shelf life of vegetable oils, which are very important aspects of marketing and human health. Most of conventional methods used to investigate oxidative stability requires long time experimental procedures with high consumption of chemical inputs for the preparation or extraction of sample compounds. In this work we propose a time-resolved thermal lens method to analyze photostability of edible oils by quantitative measurement of photoreaction cross-section. An all-numerical routine is employed to solve a complex theoretical problem involving photochemical reaction, thermal lens effect, and mass diffusion during local laser excitation. The photostability of pure oil and oils with natural and synthetic antioxidants is investigated. The thermal lens results are compared with those obtained by conventional methods, and a complete set of physical properties of the samples is presented.

  14. Investigation into photostability of soybean oils by thermal lens spectroscopy.

    Science.gov (United States)

    Savi, E L; Malacarne, L C; Baesso, M L; Pintro, P T M; Croge, C; Shen, J; Astrath, N G C

    2015-06-15

    Assessment of photochemical stability is essential for evaluating quality and the shelf life of vegetable oils, which are very important aspects of marketing and human health. Most of conventional methods used to investigate oxidative stability requires long time experimental procedures with high consumption of chemical inputs for the preparation or extraction of sample compounds. In this work we propose a time-resolved thermal lens method to analyze photostability of edible oils by quantitative measurement of photoreaction cross-section. An all-numerical routine is employed to solve a complex theoretical problem involving photochemical reaction, thermal lens effect, and mass diffusion during local laser excitation. The photostability of pure oil and oils with natural and synthetic antioxidants is investigated. The thermal lens results are compared with those obtained by conventional methods, and a complete set of physical properties of the samples is presented. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Photographic zoom fisheye lens design for DSLR cameras

    Science.gov (United States)

    Yan, Yufeng; Sasian, Jose

    2017-09-01

    Photographic fisheye lenses with fixed focal length for cameras with different sensor formats have been well developed for decades. However, photographic fisheye lenses with variable focal length are rare on the market due in part to the greater design difficulty. This paper presents a large aperture zoom fisheye lens for DSLR cameras that produces both circular and diagonal fisheye imaging for 35-mm sensors and diagonal fisheye imaging for APS-C sensors. The history and optical characteristics of fisheye lenses are briefly reviewed. Then, a 9.2- to 16.1-mm F/2.8 to F/3.5 zoom fisheye lens design is presented, including the design approach and aberration control. Image quality and tolerance performance analysis for this lens are also presented.

  16. Broadband Wide Angle Lens Implemented with Dielectric Metamaterials

    Directory of Open Access Journals (Sweden)

    Anthony Starr

    2011-08-01

    Full Text Available The Luneburg lens is a powerful imaging device, exhibiting aberration free focusing for parallel rays incident from any direction. However, its advantages are offset by a focal surface that is spherical and thus difficult to integrate with standard planar detector and emitter arrays. Using the recently developed technique of transformation optics, it is possible to transform the curved focal surface to a flat plane while maintaining the perfect focusing behavior of the Luneburg over a wide field of view. Here we apply these techniques to a lesser-known refractive Luneburg lens and implement the design with a metamaterial composed of a semi-crystalline distribution of holes drilled in a dielectric. In addition, we investigate the aberrations introduced by various approximations made in the implementation of the lens. The resulting design approach has improved mechanical strength with small aberrations and is ideally suited to implementation at infrared and visible wavelengths.

  17. Bilateral ectopia lentis with isolated lens coloboma in Marfan syndrome

    Directory of Open Access Journals (Sweden)

    Sahu, Sabin

    2016-12-01

    Full Text Available A rare case of bilateral ectopia lentis with isolated lens coloboma in Marfan syndrome is reported. A 21-year-old female presented with decreased vision in both eyes. Her unaided visual acuity was 20/200 and 20/400 in the right and left eye, respectively, improving to 20/40 with –4.5 DS/–3.0 DC x 10° correction in the right eye and 20/80 with –10.0 DS/–6.5 Dc x10° correction in the left eye. On slit lamp examination under mydriasis, both eyes revealed ectopia lentis with lens coloboma and stretched zonules. Fundus examination revealed pigmentary changes at the fovea. On systemic evaluation, she was diagnosed with Marfan syndrome. She was prescribed a refractive correction in form of a contact lens and kept under observation.

  18. 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.

  19. 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.

  20. Central vault in dry eye patients successfully wearing scleral lens.

    Science.gov (United States)

    Sonsino, Jeffrey; Mathe, Dora Sztipanovits

    2013-09-01

    Scleral contact lenses are used to treat symptoms of severe dry eyes. Procedures for fitting scleral lenses have been vague because of lack of standardized guidelines. This retrospective case series sought to establish average vault over central cornea in successful scleral lens wearers with dry eyes. Anterior segment optical coherence tomography was used to measure the distance between the posterior lens surface and cornea in 20 eyes of 12 consecutive patients successfully fit in the Vanderbilt Scleral Lens Clinic. Mean vault was 380 ± 110 μm. There was no correlation between vault and corneal curvature or vault and visual acuity. With a large SD in average vault, precision in central vault does not seem to be important in scleral contact lenses for successful fit for dry eyes.

  1. An integral-field spectroscopic strong lens survey

    International Nuclear Information System (INIS)

    Bolton, Adam S; Burles, Scott

    2007-01-01

    We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS and nearly Poisson-limited sky subtraction

  2. Optical architecture of HoloLens mixed reality headset

    Science.gov (United States)

    Kress, Bernard C.; Cummings, William J.

    2017-06-01

    HoloLens by Microsoft Corp. is the world's first untethered Mixed Reality (MR) Head Mounted Display (HMD) system, released to developers in March 2016 as a Development Kit. We review in this paper the various display requirements and subsequent optical hardware choices we made for HoloLens. Its main achievements go along performance and comfort for the user: it is the first fully untethered MR headset, with the highest angular resolution and the industry's largest eyebox. It has the first inside-out global sensor fusion system including precise head tracking and 3D mapping all controlled by a fully custom on-board GPU. Based on such achievements, HoloLens came out as the most advanced MR system today. Additional features may be implemented in next generations MR headsets, leading to the ultimate experience for the user, and securing the upcoming fabulous AR/MR market predicted by most analysts.

  3. Morphological changes in the conjunctiva, episclera and sclera following short-term miniscleral contact lens wear in rigid lens neophytes.

    Science.gov (United States)

    Alonso-Caneiro, David; Vincent, Stephen J; Collins, Michael J

    2016-02-01

    To quantify the influence of short-term wear of miniscleral contact lenses on the morphology of the corneo-scleral limbus, the conjunctiva, episclera and sclera. OCT images of the anterior eye were captured before, immediately following 3h of wear and then 3h after removal of a miniscleral contact lens for 10 young (27 ± 5 years) healthy participants (neophyte rigid lens wearers). The region of analysis encompassed 1mm anterior, to 3.5mm posterior to the scleral spur. Natural diurnal variations in thickness were measured on a separate day and compensated for in subsequent analyses. Following 3h of lens wear, statistically significant tissue thinning was observed across all quadrants, with a mean decrease in thickness of -24.1 ± 3.6 μm (pscleral spur (-48.2 ± 5.7 μm), corresponding to the approximate edge of the lens landing zone. Compression of the conjunctiva/episclera accounted for about 70% of the changes. Optimal fitting miniscleral contact lenses worn for three hours resulted in significant tissue compression in young healthy eyes, with the greatest thinning observed superiorly, potentially due to the additional force of the eyelid, with a partial recovery of compression 3h after lens removal. Most of the morphological changes occur in the conjunctiva/episclera layers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Combined 23-gauge transconjunctival vitrectomy and scleral fixation of intraocular lens without conjunctival dissection in managing lens complications.

    Science.gov (United States)

    Yeung, Ling; Wang, Nan-Kai; Wu, Wei-Chi; Chen, Kuan-Jen

    2018-04-23

    To evaluate the safety and efficacy of combined 23-gauge transconjunctival pars plana vitrectomy and scleral fixation of intraocular lens (IOL) without conjunctival dissection. A retrospective study in Chang Gung Memorial Hospital, Keelung and Taoyuan, Taiwan. Patients receiving combined 23-gauge transconjunctival pars plana vitrectomy and scleral fixation of IOL without conjunctival dissection were enrolled. The ocular findings, causes of lens complication, surgical procedures, type of IOL used, and complications were documented. We included 40 eyes from 39 patients (27 male, 12 female) with a mean age of 59.5 [standard deviation (±) 14.8] years old. The mean follow-up duration was 6.8 ± 5.4 months. The cause of lens complications was ocular trauma in 24 (60%) eyes, cataract surgery complications in 11 (28%) eyes, and spontaneous subluxation of crystalline lens in 5 (13%) eyes. The overall best corrected visual acuity (BCVA) (logMAR) improved from 1.359 ± 0.735 to 0.514 ± 0.582 (p IOL decentration was found in 3 (8%) eyes and 1 (3%) eye respectively. Combined 23-gauge transconjunctival vitrectomy and scleral fixation of IOL without conjunctival dissection is effective and safe in managing a wide variety of lens complications, with good postoperative comfort and visual recovery. Retrospective study, not applicable.

  5. Optical quality for keratoconic eyes with conventional RGP lens and simulated, customised contact lens corrections: a comparison.

    Science.gov (United States)

    Jinabhai, Amit; Neil Charman, W; O'Donnell, Clare; Radhakrishnan, Hema

    2012-05-01

    To compare monochromatic aberrations of keratoconic eyes when uncorrected, corrected with spherically-powered RGP (rigid gas-permeable) contact lenses and corrected using simulations of customised soft contact lenses for different magnitudes of rotation (up to 15°) and translation (up to 1mm) from their ideal position. The ocular aberrations of examples of mild, moderate and severe keratoconic eyes were measured when uncorrected and when wearing their habitual RGP lenses. Residual aberrations and point-spread functions of each eye were simulated using an ideal, customised soft contact lens (designed to neutralise higher-order aberrations, HOA) were calculated as a function of the angle of rotation of the lens from its ideal orientation, and its horizontal and vertical translation. In agreement with the results of other authors, the RGP lenses markedly reduced both lower-order aberrations and HOA for all three patients. When compared with the RGP lens corrections, the customised lens simulations only provided optical improvements if their movements were constrained within limits which appear to be difficult to achieve with current technologies. At the present time, customised contact lens corrections appear likely to offer, at best, only minor optical improvements over RGP lenses for patients with keratoconus. If made in soft materials, however, these lenses may be preferred by patients in term of comfort. Ophthalmic & Physiological Optics © 2012 The College of Optometrists.

  6. The potential pathogenicity of chlorhexidine-sensitive Acanthamoeba strains isolated from contact lens cases from asymptomatic individuals in Tenerife, Canary Islands, Spain.

    Science.gov (United States)

    Martín-Navarro, Carmen M; Lorenzo-Morales, Jacob; Cabrera-Serra, M Gabriela; Rancel, Fernando; Coronado-Alvarez, Nieves M; Piñero, José E; Valladares, Basilio

    2008-11-01

    Pathogenic strains of the genus Acanthamoeba are causative agents of a serious sight-threatening infection of the eye known as Acanthamoeba keratitis. The prevalence of this infection has risen in the past 20 years, mainly due to the increase in number of contact lens wearers. In this study, the prevalence of Acanthamoeba in a risk group constituted by asymptomatic contact lens wearers from Tenerife, Canary Islands, Spain, was evaluated. Contact lenses and contact lens cases were analysed for the presence of Acanthamoeba isolates. The isolates' genotypes were also determined after rDNA sequencing. The pathogenic potential of the isolated strains was subsequently established using previously described molecular and biochemical assays, which allowed the selection of three strains with high pathogenic potential. Furthermore, the sensitivity of these isolates against two standard drugs, ciprofloxacin and chlorhexidine, was analysed. As the three selected strains were sensitive to chlorhexidine, its activity and IC(50) were evaluated. Chlorhexidine was found to be active against these strains and the obtained IC(50) values were compared to the concentrations of this drug present in contact lens maintenance solutions. It was observed that the measured IC(50) was higher than the concentration found in these maintenance solutions. Therefore, the ineffectiveness of chlorhexidine-containing contact lens maintenance solutions against potentially pathogenic strains of Acanthamoeba is demonstrated in this study.

  7. Formation of hydroxyl radicals in the human lens is related to the severity of nuclear cataract

    DEFF Research Database (Denmark)

    Garner, B; Davies, Michael Jonathan; Truscott, R J

    2000-01-01

    was significantly more intense in the nuclear region of the type IV compared to the type II lenses. The ability of individual lens nuclei and cortices to stimulate HO. production was positively correlated. The DMPO-HO. signal was competitively inhibited by ethanol, confirming that the DMPO-HO. signal was due to HO...... of redox-active metal ions in the tissue. Analysis of lenses for total Fe and Cu (using atomic absorption spectrometry) showed that the more advanced type IV lenses tended to have higher Fe, but similar Cu, levels compared to the type II lenses. The levels of both metals were lower in non...

  8. A magnetic lens electron spectrometer with simultaneous momentum and energy selection

    International Nuclear Information System (INIS)

    Julin, R.; Kantele, J.; Passoja, A.

    1975-01-01

    A preliminary version of a combined swept-current magnetic lens plus Si(Li) electron spectrometer with simultaneous momentum and energy selection is presented. Results from test runs indicate that the spectrometer will be featuring good energy resolution and line shape, moderate transmission, and low background. The spectrometer is intended for in-beam measurements of conversion electron lines up to several MeV in energy and for nanosecond lifetime determinations, as well as for off-line studies of continuous beta-ray spectra and conversion lines from shortlived activities. (Auth.)

  9. Aero-acoustics noise assessment for Wind-Lens turbine

    International Nuclear Information System (INIS)

    Hashem, I.; Mohamed, M.H.; Hafiz, A.A.

    2017-01-01

    This paper introduces an aero-acoustic computational study that investigates the noise caused by one of the most promising wind energy conversion concepts, namely the 'Wind-Lens' technology. The hybrid method - where the flow field and acoustic field are solved separately, was deemed to be an appropriate tool to compute this study. The need to investigate this phenomenon increased gradually, since the feasibility of utilizing Wind-Lens turbine within densely populated cities and urban areas depends largely on their noise generation. Ffowcs Williams-Hawkings (FW-H) equation and its integral solution are used to predict the noise radiating to the farfield. CFD Simulations of transient three-dimensional flow field using (URANS) unsteady Reynolds-averaged Navier-Stokes equations are computed to acquire the acoustic sources location and sound intensity. Then, the noise propagates from the before-mentioned sources to pre-defined virtual microphones positioned in different locations. ANSYS-FLUENT is used to calculate the flow field on and around such turbines which is required for the FW-H code. Some effective parameters are investigated such as Wind-Lens shape, brim height and tip speed ratio. Comparison of the noise emitted from the bare wind turbine and different types of Wind-Lens turbine reveals that, the Wind-Lens generates higher noise intensity. - Highlights: • Aero-acoustic noise generated by wind turbines are one of the major challenges. • Noise from wind turbine equipped with a brimmed diffuser is investigated. • A computational aero-acoustic study using the hybrid method is introduced. • Effective parameters are studied such Wind-Lens shape, brim height and speed ratio. • The optimal shape has a moderate power coefficient and the less noise generation.

  10. GRAVITATIONAL LENS MODELING WITH GENETIC ALGORITHMS AND PARTICLE SWARM OPTIMIZERS

    International Nuclear Information System (INIS)

    Rogers, Adam; Fiege, Jason D.

    2011-01-01

    Strong gravitational lensing of an extended object is described by a mapping from source to image coordinates that is nonlinear and cannot generally be inverted analytically. Determining the structure of the source intensity distribution also requires a description of the blurring effect due to a point-spread function. This initial study uses an iterative gravitational lens modeling scheme based on the semilinear method to determine the linear parameters (source intensity profile) of a strongly lensed system. Our 'matrix-free' approach avoids construction of the lens and blurring operators while retaining the least-squares formulation of the problem. The parameters of an analytical lens model are found through nonlinear optimization by an advanced genetic algorithm (GA) and particle swarm optimizer (PSO). These global optimization routines are designed to explore the parameter space thoroughly, mapping model degeneracies in detail. We develop a novel method that determines the L-curve for each solution automatically, which represents the trade-off between the image χ 2 and regularization effects, and allows an estimate of the optimally regularized solution for each lens parameter set. In the final step of the optimization procedure, the lens model with the lowest χ 2 is used while the global optimizer solves for the source intensity distribution directly. This allows us to accurately determine the number of degrees of freedom in the problem to facilitate comparison between lens models and enforce positivity on the source profile. In practice, we find that the GA conducts a more thorough search of the parameter space than the PSO.

  11. 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.

  12. Immunoglobulin concentration in tears of contact lens wearers.

    Science.gov (United States)

    Maurya, Rajendra P; Bhushan, Prashant; Singh, Virendra P; Singh, Mahendra K; Kumar, Prakash; Bhatia, Ravindra P S; Singh, Usha

    2014-01-01

    To evaluate changes in the concentration of tear immunoglobulins in contact lens wearers. A total of 45 cases including 23 contact lens wearers (43 eyes) and 22 age and sex matched healthy controls having no ocular pathology were studied for immunoglobulins (IgA, IgG, IgM) in their tears by single radial immunodiffusion method. Most of the cases used soft (56.6%) and semi-soft gas permeable (30.4%) contact lenses. Tear IgM was detected in only 17.4% and tear IgG in 43.6% of contact lens wearers, while in controls IgG was detected in 9.1% but none of the controls had IgM. There was a significant rise in total tear IgA (13.17 ± 4.44 mg/dl) in contact lens wearer as compared to controls (8.93 ± 3.79 mg/dl). Rise of tear IgA was more in symptomatic patients (15.38 ± 5.28 mg/dl) and in those wearing hard (19.73 ± 5.43 mg/dl) and semi-soft contact lenses (13.31 ± 5.43 mg/dl). A significant increase in tear IgA was noticed in subjects wearing lenses for >3 years (15.69 ± 5.39 mg/dl). About 43.4% of lens wearers were symptomatic and 80% of their lenses showed deposits and/or haziness. All cases with IgM in tear were symptomatic. The relation of immunoglobulin concentration with increasing duration of wear and material of contact lens shows that tear immunoglobulin rise accrues due to mechanical stimulation, hence contact lenses should not be used for a long period and lenses of hard nature should be discouraged. The maintenance, cleaning and deproteinization of the lenses are of high importance to avoid immunostimulation.

  13. Geometric optical optimization of the corneal lens of Notonecta glauca.

    Science.gov (United States)

    Horváth, G

    1989-08-09

    The optimal shape of the corneal lens of the water bug backswimmer (Notonecta glauca) and the optimal shape and position of the thin transition layer between the distal and proximal units of its cornea are theoretically determined. Using a geometric optical method, first the shape of a geometric interface between the lens units is determined, which eliminates the longitudinal spherical aberration. This interface is investigated for differently formed thick lenses when the medium in contact with the entrance surface of the lens is water or air. The optimal transition layer for the amphibious backswimmer is that, the boundaries of which are the theoretical interfaces for water and air, and the refractive index varies continuously in it. The optimal shape of the corneal lens is determined, with the disadvantageous lenses, with respect to the possible minimal spherical aberration and amount of reflected light from the transition layer, being rejected. The optimal position of the transition layer in the cornea can be obtained from the minimization of the amount of diffracted light on the marginal connection of the layers. The optimal corneal lens for backswimmer has ellipsoid boundary surfaces; the optimal transition layer in it is thin bell-shaped, at the marginal connection of which there is no dimple, the maximum of the layer is on the margin of the cornea. The shape of the theoretically optimal corneal lens, the shape and position of the theoretically optimal transition layer agree well with those of Notonecta glauca. The question posed, the geometric optical method used and the results presented are of general importance, and not only with respect to vision in the bug Notonecta, but also in the fossil trilobites, or in the wave guide theories which have been employed in similar modelling problems, in design of system of lenses without spherical aberration, for example.

  14. Temporal integration of visual signals in lens compensation (a review).

    Science.gov (United States)

    Zhu, Xiaoying

    2013-09-01

    Postnatal eye growth is controlled by visual signals. When wearing a positive lens that causes images to be focused in front of the retina (myopic defocus), the eye reduces its rate of ocular elongation and increases choroidal thickness to move the retina forward to meet the focal plane of the eye. When wearing a negative lens that causes images to be focused behind the retina (hyperopic defocus), the opposite happens. This review summarizes how the retina integrates the constantly changing visual signals in a non-linear fashion to guide eye growth in chicks: (1a) When myopic or hyperopic defocus is interrupted by a daily episode of normal vision, normal vision is more effective in reducing myopia caused by hyperopic defocus than in reducing hyperopia caused by myopic defocus; (1b) when the eye experiences alternating myopic and hyperopic defocus, the eye is more sensitive to myopic defocus than to hyperopic defocus and tends to develop hyperopia, even if the duration of hyperopic defocus is much longer than the duration of myopic defocus; (2) when the eye experiences brief, repeated episodes of defocus by wearing either positive or negative lenses, lens compensation depends on the frequency and duration of individual episodes of lens wear, not just the total daily duration of lens wear; and (3) further analysis of the time constants for the hypothesized internal emmetropization signals show that, while it takes approximately the same amount of time for the signals to rise and saturate during lens-wearing episodes, the decline of the signals between episodes depends strongly on the sign of defocus and the ocular component. Although most extensively studied in chicks, the nonlinear temporal integration of visual signals has been found in other animal models. These findings may help explain the complex etiology of myopia in school-aged children and suggest ways to slow down myopia progression. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Diffraction enhanced X-ray imaging of mammals crystalline lens

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, A. [Departamento de Fisica Aplicada, USP, CP 66318, 05315-970 Sao Paulo, SP (Brazil)]. E-mail: antunes@if.usp.br; Hoennicke, M.G. [LORXI, Departamento de Fisica, Universidade Federal do Parana, Curitiba (Brazil); Safatle, A.M.V. [Faculdade de Medicina Veterinaria e Zootecnia, USP, 05508-900 Sao Paulo, SP (Brazil); Cusatis, C. [LORXI, Departamento de Fisica, Universidade Federal do Parana, Curitiba (Brazil); Moraes Barros, P.S. [Faculdade de Medicina Veterinaria e Zootecnia, USP, 05508-900 Sao Paulo, SP (Brazil); Morelhao, S.L. [Departamento de Fisica Aplicada, USP, CP 66318, 05315-970 Sao Paulo, SP (Brazil)

    2005-08-15

    Crystalline lenses are transparent biological materials where the organization of the lens fibers can also be affected by changes at molecular level, and therefore the structure and morphology of the tissue can be correlated to the loss of transparency of the lens. In this work, internal structure of mammal lenses regarding the long-range ordering of the fibers are investigated by diffraction enhanced X-ray imaging (DEI) radiography. Moreover, DEI and absorption X-ray synchrotron radiographs for healthy and cataractous crystalline lenses are compared. Significant differences in healthy and cataractous crystalline lenses are observed.

  16. Diffraction enhanced X-ray imaging of mammals crystalline lens

    International Nuclear Information System (INIS)

    Antunes, A.; Hoennicke, M.G.; Safatle, A.M.V.; Cusatis, C.; Moraes Barros, P.S.; Morelhao, S.L.

    2005-01-01

    Crystalline lenses are transparent biological materials where the organization of the lens fibers can also be affected by changes at molecular level, and therefore the structure and morphology of the tissue can be correlated to the loss of transparency of the lens. In this work, internal structure of mammal lenses regarding the long-range ordering of the fibers are investigated by diffraction enhanced X-ray imaging (DEI) radiography. Moreover, DEI and absorption X-ray synchrotron radiographs for healthy and cataractous crystalline lenses are compared. Significant differences in healthy and cataractous crystalline lenses are observed

  17. Patient compliance and its influence on contact lens wearing problems.

    Science.gov (United States)

    Collins, M J; Carney, L G

    1986-12-01

    One hundred consecutively presenting patients, fifty from each of two contact lens clinics, were questioned about the procedures encountered in care and maintenance of their contact lenses and asked to demonstrate their use of those procedures. Their clinic records were then analyzed for the occurrence of signs and symptoms that were related potentially to noncompliance with instructions and procedures, and that could not be otherwise explained. Only 26% of patients were fully complaint. Noncompliance with instructions was related strongly to the occurrence of signs and symptoms indicative of potential wearing problems. Improvements in the level of patient compliance with instructions is likely to bring about increased patient success with contact lens wearing.

  18. The dangers of distilled water in contact lens maintenance.

    Science.gov (United States)

    Josephson, J E; Caffery, B E

    1988-03-01

    The reports of serious corneal infection associated with hydrogel lens wear prompted us to explore the level of sterility of the distilled water used by lens wearers in our practice. Fifty patients supplied samples of their partially-used distilled water for testing. Of the samples, 12% were found to be contaminated. Five samples of previously unopened distilled water were tested and no growth was found. We recommend that patients do not use distilled water for the care of hydrogel contact lenses. Rather, sterile unit dose or multi-dose (aerosol) nonpreserved, or preserved salines can be used.

  19. Immunoglobulin Concentration in Tears of Contact Lens Wearers

    OpenAIRE

    Maurya, Rajendra P.; Bhushan, Prashant; Singh, Virendra P.; Singh, Mahendra K.; Kumar, Prakash; Bhatia, Ravindra P.S.; Singh, Usha

    2014-01-01

    Purpose: To evaluate changes in the concentration of tear immunoglobulins in contact lens wearers. Methods: A total of 45 cases including 23 contact lens wearers (43 eyes) and 22 age and sex matched healthy controls having no ocular pathology were studied for immunoglobulins (IgA, IgG, IgM) in their tears by single radial immunodiffusion method. Results: Most of the cases used soft (56.6%) and semi-soft gas permeable (30.4%) contact lenses. Tear IgM was detected in only 17.4% and tear I...

  20. Twenty years and twenty thousand contact lens patients.

    Science.gov (United States)

    Dixon, J M

    1981-01-01

    A self contained non commercial private office laboratory staffed by office personnel has been used to prepare contact lenses for private office patients. These lenses include hard contact lenses of various materials and various designs. During the past ten years extended wear hydrophilic soft lenses have been prepared in the same manner as hard lenses, all custom made with lens powers, base curves, diameters, and thickness designed according to the needs of each patient. This has provided strict medical supervision and lens maintenance with maximum convenience for patients and the ophthalmologist.

  1. Smart Reinvention of the Contact Lens with Graphene.

    Science.gov (United States)

    Choi, Kyoungjun; Park, Hyung Gyu

    2017-06-27

    With potential benefits to the 71 million contact lens users worldwide, contact lenses are being reinvented in the form of smart wearable electronics. In this issue of ACS Nano, Lee et al. report on the fascinating functions of a graphene-based smart contact lens that is able to protect eyes from electromagnetic waves and dehydration. Graphene and two-dimensional materials can be exploited in many opportunities in the development of smart contact lenses. Here, we briefly review and describe prospects for the future of smart contact lenses that incorporate graphene in their platforms.

  2. Non-Thermal Electromagnetic Radiation Damage to Lens Epithelium

    OpenAIRE

    Bormusov, Elvira; P.Andley, Usha; Sharon, Naomi; Sch?chter, Levi; Lahav, Assaf; Dovrat, Ahuva

    2008-01-01

    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 us...

  3. Contact Lens Wear for Visual Disorders in USAF Aviators.

    Science.gov (United States)

    1986-09-01

    contact 10-1 ’ .. . - w r" -,lSflZ.1,’y..,’.,L mp p,, tp. -,- ’’..r • %- 4o- Figure 1. Scleral contact lenses . 4.eN -.. r-4- Figure 2. Corneal... contact lens, Soft contact lens, Keratoconus, Aphakia * ABSTRACT (Contnue on reverse if necessary and identify by block number) ontact lenses are an...alternative method to spectacles for correcting refractive errors, but he U.S. Air Force prohibits the wearing of contact lenses by all aircrew

  4. Ball Lens Fiber Optic Sensor based Smart Handheld Microsurgical Instrument.

    Science.gov (United States)

    Song, Cheol; Gehlbach, Peter L; Kang, Jin U

    2013-03-20

    During freehand performance of vitreoretinal microsurgery the surgeon must perform precise and stable maneuvers that achieve surgical objectives and avoid surgical risk. Here, we present an improved smart handheld microsurgical tool which is based on a ball lens fiber optic sensor that utilizes common path swept source optical coherence tomography. Improvements include incorporation of a ball lens single mode fiber optic probe that increases the working angle of the tool to greater than 45 degrees; and increases the magnitude of the distance sensing signal through water. Also presented is a cutting function with an improved ergonomic design.

  5. Contact lens care solution killing efficacy against Acanthamoeba castellanii by in vitro testing and live-imaging.

    Science.gov (United States)

    Kolar, Satya Sree N; Manarang, Joseph C; Burns, Alan R; Miller, William L; McDermott, Alison M; Bergmanson, Jan P G

    2015-12-01

    In the past decade there has been an increased incidence of Acanthamoeba keratitis, particularly in contact lens wearers. The aim of this study was to utilize in vitro killing assays and to establish a novel, time-lapse, live-cell imaging methodology to demonstrate the efficacy of contact lens care solutions in eradicating Acanthamoeba castellanii (A. castellanii) trophozoites and cysts. Standard qualitative and quantitative in vitro assays were performed along with novel time-lapse imaging coupled with fluorescent dye staining that signals cell death. Quantitative data obtained demonstrated that 3% non-ophthalmic hydrogen peroxide demonstrated the highest percent killing at 87.4% corresponding to a 4.4 log kill. The other contact lens care solutions which showed a 72.9 to 29.2% killing which was consistent with 4.3-2.8 log reduction in trophozoite viability. Both analytical approaches revealed that polyquaternium/PHMB-based was the least efficacious in terms of trophicidal activity. The cysticidal activity of the solutions was much less than activity against trophozoites and frequently was not detected. Live-imaging provided a novel visual endpoint for characterizing the trophocidal activity of the care solutions. All solutions caused rapid rounding or pseudocyst formation of the trophozoites, reduced motility and the appearance of different morphotypes. Polyquaternium/alexidine-based and peroxide-based lens care system induced the most visible damage indicated by significant accumulation of debris from ruptured cells. Polyquaternium/PHMB-based was the least effective showing rounding of the cells but minimal death. These observations are in keeping with care solution biocides having prominent activity at the plasma membrane of Acanthamoeba. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Minimum Lens Size Supporting the Leaky-Wave Nature of Slit Dipole Antenna at Terahertz Frequency

    Directory of Open Access Journals (Sweden)

    Niamat Hussain

    2016-01-01

    Full Text Available We designed a slit dipole antenna backed by an extended hemispherical silicon lens and investigated the minimum lens size in which the slit dipole antenna works as a leaky-wave antenna. The slit dipole antenna consists of a planar feeding structure, which is a center-fed and open-ended slot line. A slit dipole antenna backed by an extended hemispherical silicon lens is investigated over a frequency range from 0.2 to 0.4 THz with the center frequency at 0.3 THz. The numerical results show that the antenna gain responses exhibited an increased level of sensitivity to the lens size and increased linearly with increasing lens radius. The lens with the radius of 1.2λo is found to be the best possible minimum lens size for a slit dipole antenna on an extended hemispherical silicon lens.

  7. Tomographic method for measurement of the gradient refractive index of the crystalline lens. I. The spherical fish lens.

    Science.gov (United States)

    Acosta, Eva; Vazquez, Daniel; Garner, Leon; Smith, George

    2005-03-01

    We present an iterative tomographic algorithm to reconstruct refractive-index profiles for meridional planes of the lens of the spherical fish eye from measurements of deflection angles of refracted rays. Numerical simulations show that the algorithm allows accuracy up to the fourth decimal place, provided that the refractive index can be regarded as an analytical function of the radial coordinate and the experimental errors are neglected. An experimental demonstration is given by applying the algorithm to retrieve the refractive-index profile of a spherical fish lens. The method is conceptually simple and does not require matching of the index of the surrounding medium to that of the surface of the lens, and the related iterative algorithm rapidly converges.

  8. Life through a Lens: Risk, Surveillance and Subjectivity

    Directory of Open Access Journals (Sweden)

    Gavin Smith

    2016-03-01

    Full Text Available Drawing on findings from a two-year empirical study examining the culture of closed-circuit television (CCTV operation in the UK, this paper analyses how CCTV camera operators subjectively experience the visual media that they work to produce. It seeks to excavate some of the social meanings that these vicarious risk flâneurs ascribe to the telemediated events that they indirectly encounter, and how these ‘narratives of the street’ come to inscribe themselves on the subjectivities of the camera operators in a disciplinary manner. In so doing, the paper reveals the work of watching to be an ambiguous social practice, an activity that far exceeds its formal framing as a dispassionate and standardised procedure. As such, I contend that CCTV camera operators engage in two distinct modes of work – ‘surface’ and ‘deep’ – as they watch the screens and codify the spectacles that are mediated through the camera lens. The ‘surface’ work they enact is officially acknowledged and concerns their focusing attention on the screens to identify harmful behaviours, to capture evidence and to share information with other collaborators in the security network. This mode of work is principally performed for professional imperatives and economic returns. In contrast, the ‘deep’ work rituals they execute are informal in scope and therapeutic in purpose. Such individualised practices are an unseen and unrecognised work relation that mitigates the negative effects of CCTV viewing. They are operationalised through diverse behavioural repertoires which function to insulate the self from its exposure to mediated traumas, and from the contradiction of mobilising ‘(inaction at a distance’. Overall, the paper accentuates the messy realities that hinge on the practice of urban surveillance, showing these realities to be meditated by the vagaries of subjective experience and social relations.

  9. Home care technology through an ability expectation lens.

    Science.gov (United States)

    Wolbring, Gregor; Lashewicz, Bonnie

    2014-06-20

    Home care is on the rise, and its delivery is increasingly reliant on an expanding variety of health technologies ranging from computers to telephone "health apps" to social robots. These technologies are most often predicated on expectations that people in their homes (1) can actively interact with these technologies and (2) are willing to submit to the action of the technology in their home. Our purpose is to use an "ability expectations" lens to bring together, and provide some synthesis of, the types of utility and disadvantages that can arise for people with disabilities in relation to home care technology development and use. We searched the academic databases Scopus, Web of Science, EBSCO ALL, IEEE Xplore, and Compendex to collect articles that had the term "home care technology" in the abstract or as a topic (in the case of Web of Science). We also used our background knowledge and related academic literature pertaining to self-diagnosis, health monitoring, companionship, health information gathering, and care. We examined background articles and articles collected through our home care technology search in terms of ability expectations assumed in the presentation of home care technologies, or discussed in relation to home care technologies. While advances in health care support are made possible through emerging technologies, we urge critical examination of such technologies in terms of implications for the rights and dignity of people with diverse abilities. Specifically, we see potential for technologies to result in new forms of exclusion and powerlessness. Ableism influences choices made by funders, policy makers, and the public in the development and use of home health technologies and impacts how people with disabilities are served and how useful health support technologies will be for them. We urge continued critical examination of technology development and use according to ability expectations, and we recommend increasing incorporation of

  10. The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample of Massive Early-Type Lens Galaxies

    Science.gov (United States)

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Moustakas, Leonidas A.

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple nebular emission lines at a redshift significantly higher than that of the SDSS target galaxy. The SLACS survey is optimized to detect bright early-type lens galaxies with faint lensed sources in order to increase the sample of known gravitational lenses suitable for detailed lensing, photometric, and dynamical modeling. In this paper, the first in a series on the current results of our HST Cycle 13 imaging survey, we present a catalog of 19 newly discovered gravitational lenses, along with nine other observed candidate systems that are either possible lenses, nonlenses, or nondetections. The survey efficiency is thus >=68%. We also present Gemini 8 m and Magellan 6.5 m integral-field spectroscopic data for nine of the SLACS targets, which further support the lensing interpretation. A new method for the effective subtraction of foreground galaxy images to reveal faint background features is presented. We show that the SLACS lens galaxies have colors and ellipticities typical of the spectroscopic parent sample from which they are drawn (SDSS luminous red galaxies and quiescent MAIN sample galaxies), but are somewhat brighter and more centrally concentrated. Several explanations for the latter bias are suggested. The SLACS survey provides the first statistically significant and homogeneously selected sample of bright early-type lens galaxies, furnishing a powerful probe of the structure of early-type galaxies within the half-light radius. The high confirmation rate of lenses in the SLACS survey suggests consideration of spectroscopic lens discovery as an explicit science goal of future spectroscopic galaxy surveys.

  11. Lens subluxation grading system: predictive value for ectopia lentis surgical outcomes

    OpenAIRE

    Mauro Waiswol; Niro Kasahara

    2009-01-01

    Objective: To present a classification system to grade ectopia lentis and to assess its usefulness as a predictor for surgical outcomes. Methods: Fifty-one eyes of 28 patients with either simple (19 patients) or Marfan syndrome-associated ectopia lentis (nine patients) with variable degrees of subluxation were operated on. Lens subluxation intensity was graded according to the lens subluxation grading system (LSGS) from grade 1 (lens on the whole pupillary area) up to grade 4 (lens absent fro...

  12. Microbial contamination of soft contact lenses & accessories in asymptomatic contact lens users.

    Science.gov (United States)

    Thakur, Deeksha V; Gaikwad, Ujjwala N

    2014-08-01

    With increasing use of soft contact lenses the incidence of contact lens induced infections is also increasing. This study was aimed to assess the knowledge of new and existing contact lens users about the risk of microbial contamination associated with improper use and maintenance of contact lenses, type of microbial flora involved and their potential to cause ophthalmic infections. Four samples each from 50 participants (n=200) were collected from the lenses, lens care solutions, lens care solution bottles and lens cases along with a questionnaire regarding their lens use. The samples were inoculated onto sheep blood agar, Mac Conkey's agar and Sabouraud's dextrose agar. Organisms were identified using standard laboratory protocols. Overall rate of microbial contamination among the total samples was 52 per cent. The most and the least contaminated samples were found to be lens cases (62%) and lens care solution (42%), respectively. The most frequently isolated contaminant was Staphylococcus aureus (21%) followed by Pseudomonas species (19.5%). Majority (64%) of the participants showed medium grade of compliance to lens cleaning practices. Rate of contamination was 100 and 93.75 per cent respectively in those participants who showed low and medium compliance to lens care practices as compared to those who had high level of compliance (43.75%) (PLens care practices amongst the participants were not optimum which resulted into high level contamination. Hence, creating awareness among the users about the lens care practices and regular cleaning and replacements of lens cases are required.

  13. Bacterial Adhesion Forces to Ag-Impregnated Contact Lens Cases and Transmission to Contact Lenses

    NARCIS (Netherlands)

    Qu, Wenwen; Busscher, Henk J.; van der Mei, Henny C.; Hooymans, Johanna M. M.

    Purpose: To measure adhesion forces of Pseudomonas aeruginosa, Staphylococcus aureus, and Serratia marcescens to a rigid contact lens (CL), standard polypropylene, and Ag-impregnated lens cases using atomic force microscopy and determine bacterial transmission from lens case to CL. Methods: Adhesion

  14. Radial focusing of a relativistic electron beam in a bipotential electrostatic lens

    International Nuclear Information System (INIS)

    Genoni, T.C.

    1994-01-01

    The focusing of a relativistic electron beam in a bipotential electrostatic lens is discussed. An iterative scheme for the solution of the paraxial ray equation is used to derive approximate analytic formulas for the lens parameters and lens transfer matrix elements. The formulas are compared to results of direct numerical integration of the paraxial ray equation

  15. 21 CFR 800.12 - Contact lens solutions and tablets; tamper-resistant packaging.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Contact lens solutions and tablets; tamper....12 Contact lens solutions and tablets; tamper-resistant packaging. (a) General. Unless contact lens solutions used, for example, to clean, disinfect, wet, lubricate, rinse, soak, or store contact lenses and...

  16. [Visual quality comparison after multifocal toric intraocular lens or monofocal toric intraocular lens implantation].

    Science.gov (United States)

    Feng, K; Guo, H K; Zhang, Y L; Wu, Z

    2017-04-11

    Objective: To compare visual quality and satisfaction after multifocal toric intraocular lens (Acrysof IQ Restor toric, ART) and monofocal toric intraocular lens implantation in patients. Methods: It was a prospective nonrandomized Phase Ⅲ clinical trial. Patients with age-related cataract and corneal astigmatism were enrolled and accepted phacoemulsification combined with implantation of intraocular lens (IOL) in Henan Provincial Eye Hospital during March 2013 to December 2014. Fifty-six cases were divided into two groups according to which IOL they chose. ART group included 28 cases (3l eyes) aged from 41.0 to 72.0 years, with an average age of 61.5 years; toric group included 28 cases (33 eyes) aged from 42.0 to 75.0 years, with an average age of 63.5 years. Three months postoperatively, uncorrected distance visual acuity (UDVA) at 5, 70, 40 cm, corrected distance, intermediate, and near visual acuities, defocus curve, residual refractive astigmatism, rotational stability of the IOL, contrast sensitivity and patientsatisfaction were evaluated. All data were processed by statistic package deal SPSS 16.0. Postoperative visual acuity, residual astigmatism, IOL axial rotation and contrast sensitivity were compared by independent samples t test; preoperative and postoperative corneal astigmatism were compared by paired t -test; spectacle independency and halo incidence were processed by χ(2) test; visual satisfaction score was analyzed by Mann-Whitney test. Results: At 3 months postoperatively, in ART group, UDVA was (0.04±0.05), UIVA was (0.24±0.15), UNVA was (0.20±0.24). While in Toric group, UDVA was (0.06±0.04), UIVA was (0.30±0.13), UNVA was (0.47±0.21). There was no significant difference in UDVA between two groups( t= 0.79, P= 0.433). But in ART group, UIVA and UNVA were markedly better than those in Toric group( t= 2.74, P= 0.008; t= 3.45, PART group and 2.50 D (+1.00--1.50 D) in the Toric group. Average postoperative residual astigmatism was (-0.45

  17. Michel Foucault se historiografiese benadering as lens in historiese ...

    African Journals Online (AJOL)

    In the article the author argues that Foucault's insights on the archaeological historiography, genealogy and discourse analysis can be used as a lens to write history as well as to deconstruct the existing historical sources. Foucault's main thesis is that history is largely an illusion. Foucault contrasts effective historiography ...

  18. J3-crystallin of the jellyfish lens: similarity to saposins

    Czech Academy of Sciences Publication Activity Database

    Piatigorsky, J.; Norman, B.; Dishaw, L. J.; Kos, L.; Horwitz, J.; Steinbach, P. J.; Kozmik, Zbyněk

    2001-01-01

    Roč. 98, č. 22 (2001), s. 12362-12367 ISSN 0027-8424 R&D Projects: GA MŠk LN00A079 Keywords : crystallin * jellyfish * lens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 10.890, year: 2001

  19. Optical turbulence in a spinning pipe gas lens

    CSIR Research Space (South Africa)

    Mafusire, C

    2009-07-01

    Full Text Available The researchers have managed to do quantitative analysis of ‘controlled’ turbulence. The researchers could control the degree of turbulence by controlling the rotation speed and wall temperature of the spinning pipe gas lens. The researchers also...

  20. On the Road : Screening Chinese Cinema through a Postmodern Lens

    NARCIS (Netherlands)

    Bian, Y.

    2016-01-01

    On the Road: Screening Chinese Cinema through a Postmodern Lens includes a variety of navigation services through the central debate on postmodernism as a cross-cultural study that recovers and represents Chinese film world of the past and the present, of home and abroad. Postmodernism in this

  1. Retinal images in the human eye with implanted intraocular lens

    Science.gov (United States)

    Zając, Marek; Siedlecki, Damian; Nowak, Jerzy

    2007-04-01

    A typical proceeding in cataract is based on the removal of opaque crystalline lens and inserting in its place the artificial intraocular lens (IOL). The quality of retinal image after such procedure depends, among others, on the parameters of the IOL, so the design of the implanted lens is of great importance. An appropriate choice of the IOL material, especially in relation to its biocompatibility, is often considered. However the parameter, which is often omitted during the IOL design is its chromatic aberration. In particular lack of its adequacy to the chromatic aberration of a crystalline lens may cause problems. In order to fit better chromatic aberration of the eye with implanted IOL to that of the healthy eye we propose a hybrid - refractive-diffractive IOL. It can be designed in such way that the total longitudinal chromatic aberration of an eye with implanted IOL equals the total longitudinal chromatic aberration of a healthy eye. In this study we compare the retinal image quality calculated numerically on the basis of the well known Liou-Brennan eye model with typical IOL implanted with that obtained if the IOL is done as hybrid (refractive-diffractive) design.

  2. Portraiture lens concept in a mobile phone camera

    Science.gov (United States)

    Sheil, Conor J.; Goncharov, Alexander V.

    2017-11-01

    A small form-factor lens was designed for the purpose of portraiture photography, the size of which allows use within smartphone casing. The current general requirement of mobile cameras having good all-round performance results in a typical, familiar, many-element design. Such designs have little room for improvement, in terms of the available degrees of freedom and highly-demanding target metrics such as low f-number and wide field of view. However, the specific application of the current portraiture lens relaxed the requirement of an all-round high-performing lens, allowing improvement of certain aspects at the expense of others. With a main emphasis on reducing depth of field (DoF), the current design takes advantage of the simple geometrical relationship between DoF and pupil diameter. The system has a large aperture, while a reasonable f-number gives a relatively large focal length, requiring a catadioptric lens design with double ray path; hence, field of view is reduced. Compared to typical mobile lenses, the large diameter reduces depth of field by a factor of four.

  3. Contact Lens Safety (A Minute of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2016-08-18

    Contact lenses are a convenient alternative to glasses, but improper care and use can result in infections which can lead to eye damage. This podcast discusses contact lens safety.  Created: 8/18/2016 by MMWR.   Date Released: 8/18/2016.

  4. New device for the radiation protection of the eye lens

    International Nuclear Information System (INIS)

    Csobaly, S.; Zarand, P.

    1980-01-01

    Lenses of 50 mm diameter and 2 mm width were ground from lead glass, equivalent to 2 mm of lead. In the case of X-radiations of different intensity and different filtering the finished glasses are equivalent to 0.73-0.78 mm of lead and they decrease the radiation exposition of the eye lens 15-fold. (L.E.)

  5. Contact-lens-related microbial keratitis: case report and review

    Directory of Open Access Journals (Sweden)

    Mark Eltis

    2011-10-01

    Full Text Available Bacterial keratitis is a serious, potentially blinding, complication most often involving overnight contact lens wear. This case report reviews the management of a patient with bacterial keratitis and discusses the etiology, differential diagnosis, classification and risk factors associated with the condition.

  6. 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).

  7. Scleral lens tolerance after corneal cross-linking for keratoconus

    NARCIS (Netherlands)

    Visser, Esther Simone; Soeters, Nienke; Tahzib, Nayyirih G.

    2015-01-01

    Purpose. Subjective and objective evaluation of scleral lens tolerance and fitting before and after corneal cross-linking (CXL) for progressive keratoconus. Methods. In this prospective cohort, evaluations were made of 18 unilateral eyes in patients who underwent CXL and had been wearing scleral

  8. Fish-eye lens designs and their relative performance

    Science.gov (United States)

    Kumler, James J.; Bauer, Martin L.

    2000-10-01

    New panoramic and immersive digital imaging developments have generated increased interest in high performance fisheye camera lenses suitable for 35 mm single lens reflex (SLR) cameras. Special concerns for such applications are the uniformity of illumination and radial image mapping. Because two hemispherical images are digitally stitched together to form a complete 360-degree x 180-degree image, the performance of the lens at the 90 degree (preferably more than 90 degree) edge of the fisheye image is just as important as the center of the image. Lateral color, high order distortion (edge compression) and severe drop-off of illumination at the full field become obvious image defects and cause seams in the immersive image. Fisheye lens designs have widely varying relative illumination and distortion across the hemispherical field of view of the lens. After describing the contributing factors to relative illumination, we survey a collection of fisheye designs and compare their illumination performance, radial mapping and lateral color. A new method of measuring relative illumination and radial mapping in the laboratory is described and results on commercially available fish-eye lenses are presented.

  9. Opaque contact lens treatment for older children with amblyopia.

    Science.gov (United States)

    Anderson, Justin E; Brown, Sandra M; Mathews, Taryn A; Mathews, Steven M

    2006-03-01

    To investigate the usefulness of daily-wear opaque contact lens treatment for older children with amblyopia. A retrospective chart review of all children undergoing opaque contact lens therapy for amblyopia between 2000 and 2003 was performed. All patients were included except for those younger than 5 years of age, those undergoing maintenance treatment only, those lost to follow-up, or those unable to cooperate with Snellen visual acuity testing. Thirteen children were identified, and seven met the inclusion criteria. The seven patients had a mean age of 7.5 years (range, 5.7-8.7 years). The causes of amblyopia were anisometropia (five patients), cataract (one patient), and strabismus (one patient). For all seven patients, the mean logMAR improvement in visual acuity was 0.52 (range, 0.26-1.22). The average duration of opaque contact lens use was 9.3 months (range, 2-21 months). Compliance problems were encountered in three patients. No major complications occurred, but one patient had an episode of mild superficial punctate keratitis. Daily-wear opaque contact lens treatment is a useful occlusion method for amblyopia treatment in older children with various practical and social impediments to skin patching. Meaningful improvement in visual acuity can be obtained, even in children older than 8 years of age.

  10. The contact lens environment: tear proteins in perspective.

    Science.gov (United States)

    Carney, L G; Hill, R M

    1985-03-01

    Tear protein deposition on contact lenses can lead to interruption or even cessation of lens wear. Yet, there are positive roles that tear proteins play in the maintenance of ocular integrity, with and without contact lenses present. One of these roles, that of tear buffering, is explored here.

  11. Immunoglobulin Concentration in Tears of Contact Lens Wearers

    Directory of Open Access Journals (Sweden)

    Rajendra P Maurya

    2014-01-01

    Conclusion: The relation of immunoglobulin concentration with increasing duration of wear and material of contact lens shows that tear immunoglobulin rise accrues due to mechanical stimulation, hence contact lenses should not be used for a long period and lenses of hard nature should be discouraged. The maintenance, cleaning and deproteinization of the lenses are of high importance to avoid immunostimulation.

  12. Drug and Contact Lens Interactions | Muntingh | South African ...

    African Journals Online (AJOL)

    "A patient who damages or loses his or her expensive hydrophilic contact lens will be annoyed - but the complaint will be much louder if the damage is caused by drugs without appropriate warning". This opening sentence from a short article by DV Ingram from the Sussex Eye Hospital, is indicative of a potential problem for ...

  13. Modeling Corneal Oxygen with Scleral Gas Permeable Lens Wear.

    Science.gov (United States)

    Compañ, Vicente; Aguilella-Arzo, Marcel; Edrington, Timothy B; Weissman, Barry A

    2016-11-01

    The main goal of this current work is to use an updated calculation paradigm, and updated boundary conditions, to provide theoretical guidelines to assist the clinician whose goal is to improve his or her scleral gas permeable (GP) contact lens wearing patients' anterior corneal oxygen supply. Our model uses a variable value of corneal oxygen consumption developed through Monod equations that disallows negative oxygen tensions within the stroma to predict oxygen tension at the anterior corneal surface of scleral GP contact lens wearing eyes, and to describe oxygen tension and flux profiles, for various boundary conditions, through the lens, tears, and cornea. We use several updated tissue and boundary parameters in our model. Tear exchange with GP scleral lenses is considered nonexistent in this model. The majority of current scleral GP contact lenses should produce some levels of corneal hypoxia under open eye conditions. Only lenses producing the thinnest of tear vaults should result in anterior corneal surface oxygen tensions greater than a presumed critical oxygen tension of 100 mmHg. We also find that corneal oxygen tension and flux are each more sensitive to modification in tear vault than to changes in lens oxygen permeability, within the ranges of current clinical manipulation. Our study suggests that clinicians would be prudent to prescribe scleral GP lenses manufactured from higher oxygen permeability materials and especially to fit without excessive corneal clearance.

  14. 1600+434 - A NEW GRAVITATIONAL LENS SYSTEM

    NARCIS (Netherlands)

    JACKSON, N; DEBRUYN, AG; MYERS, S; BREMER, MN; MILEY, GK; SCHILIZZI, RT; BROWNE, IWA; NAIR, S; WILKINSON, PN; BLANDFORD, RD; PEARSON, TJ; READHEAD, ACS

    1995-01-01

    We report the discovery of a new gravitational lens system associated with the flat-spectrum radio source 1600+434. The system has been found in a new large survey of such radio sources. It consists of a 1.4-arcsec double radio source with an associated optical double at the same position and

  15. Drying kinetic and physical properties of green laird lentil ( Lens ...

    African Journals Online (AJOL)

    Lens culinaris) in microwave drying method. The drying data were fitted to the various thin-layer models. All the models were compared using three statistical parameters, that is, coefficient of determination R2, reduced mean square of the ...

  16. A magnetic-lens - mini-orange coincidence spectrometer

    International Nuclear Information System (INIS)

    Bargholtz, C.; Holmberg, L.; Ruus, N.; Tegner, P.E.; Weiss, G.

    1997-04-01

    A coincidence spectrometer consisting of a Gerholm type magnetic lens and a permanent magnet mini-orange spectrometer is described. Electron-electron or electron-positron coincidences may be registered in various angular settings. The spectrometer has been developed mainly to search for anomalous contributions to Bhabha scattering or positrons and is at present used for such studies. 6 refs

  17. An XML file format for exchanging singlet lens specifications

    Science.gov (United States)

    Gay, Shawn C.; Gangadhara, Sanjay

    2015-10-01

    Zemax has developed an XML schema for the distribution of singlet lens specifications based on the ISO 10110 standard. In OpticStudio 15, this kind of XML data can be exported from the ISO Element Drawing analysis. The data file is then used in a feature that automates exchange of lens data between designer and manufacturer, the Cost Estimator. This Cost Estimator feature submits the XML data to various manufacturers to obtain cost estimates for prototype lens production. The workflow centered on the XML data exchange facilitates rapid cost estimate retrieval and eliminates the need for redundant manual data entry. The XML Schema Definition (XSD) for the XML format can be used with Microsoft developer tools to automatically create .NET classes to serialize and deserialize the singlet lens data to/from XML files. The format provides flexible unit specification for most parameters. Choosing XML as the basis for the file format has provided several benefits, such as the above mentioned automated serialization capabilities in .NET, a human-readable text-based format, and ready support for consumption by web services.

  18. Metallic plates lens focalizing a high power microwave beam

    International Nuclear Information System (INIS)

    Rebuffi, L.

    1987-08-01

    A metallic grating composed of thin parallel plates opportunely spaced, permits to correct the phase of an incident high power microwave beam. In this work we show how it is possible to obtain a beam focalisation (lens), a beam deflection (prisma), or a variation in the polarization (polarizer) using parallel metallic plates. The main design parameters are here presented, in order to obtain the wanted phase modification keeping low the diffraction, the reflected power, the ohmic losses and avoiding breakdowns. Following the given criteria, a metallic plate lens has been realized to focalize the 200 KW, 100 msec 60 GHz beam used in the ECRH experiment on the TFR tokamak. The experimental beam concentration followed satisfactory the design requirements. In fact, the maximum intensity increased about twice the value without lens. In correspondence of this distance a reduction of the beam size of about 50% have been measured for the -3 dB radius. The lens supported high power tests without breakdowns or increase of the reflected power

  19. Strategic Learning Capability: Through the Lens of Environmental Jolts

    Science.gov (United States)

    Moon, Hanna; Lee, Chan

    2015-01-01

    Purpose: This paper aims to deepen the understanding of strategic learning through the lens of environmental jolts. Design/methodology/approach: Strategic learning is explained from the three paradigms of organizational learning. Findings: Organizational learning provides a firm foundation to develop and elaborate the concept of strategic learning…

  20. Lightweight Inexpensive Ozone Lidar Telescope Using a Plastic Fresnel Lens

    Science.gov (United States)

    DeYoung, Russell J.; Notari, Anthony; Carrion, William; Pliutau, Denis

    2014-01-01

    An inexpensive lightweight ozone lidar telescope was designed, constructed and operated during an ozone lidar field campaign. This report summarizes the design parameters and performance of the plastic Fresnel lens telescope and shows the ozone lidar performance compared to Zemax calculations.