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Sample records for lens microcirculatory system

  1. Systemic and microcirculatory responses to progressive hemorrhage

    NARCIS (Netherlands)

    Dubin, Arnaldo; Pozo, Mario Omar; Ferrara, Gonzalo; Murias, Gastón; Martins, Enrique; Canullán, Carlos; Canales, Héctor Saul; Kanoore Edul, Vanina Siham; Estenssoro, Elisa; Ince, Can

    2009-01-01

    To compare systemic hemodynamics with microcirculatory changes at different vascular beds during progressive hemorrhage. University-based research laboratory. Twelve anesthetized, mechanically ventilated sheep. Sheep were randomly assigned to HEMORRHAGE or CONTROL group. In the HEMORRHAGE group (n =

  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. 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.)

  4. 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.

  5. 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.

  6. [Comparative pathology of the microcirculatory bed].

    Science.gov (United States)

    Strukov, A I; Vorob'eva, A A

    1976-11-01

    This paper presents an analysis of publications, mostly by Soviet authores, on clinical studies and morphological examinations of the microcirculatory bed in different pathology. It is concluded that the microcirculatory bed should be regarded as an integral system responding to the pathological effects by a local and general reaction of its structural components and by changing the rheological properties of blood. Two types of changes develop in the microcirculatory system -- sterotyped ones, typical for extreme states (various kinds of shock, hypertensive crisis, stress situations), and those specific for certain diseases (diabetes melitus, essential hypertension, athersclerosis, collagenoses, etc.). In all the above diseases the pathological process affects the functional structures of microcirculation that undergo a rearrangement in accordance with the requirements of the body. In the initial period of the disease this re-arrangement is of a compensatory nature and passes ahead of the clinical manifestations. A comparison of the pictutrs obtained by biomicroscopy of the bulbconjunctiva of the eye and of other mucosae with film preparations of the serosae demonstrates their complete similarity. Therefore, the method of biomicroscopy of the eyeball and of the mucosae as a method reflecting the state of microcirculation in the body as a whole should become an integral part of the clinical examination of patients.

  7. 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

  8. 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.

  9. International study on microcirculatory shock occurrence in acutely ill patients

    NARCIS (Netherlands)

    Vellinga, Namkje A. R.; Boerma, E. Christiaan; Koopmans, Matty; Donati, Abele; Dubin, Arnaldo; Shapiro, Nathan I.; Pearse, Rupert M.; Machado, Flavia R.; Fries, Michael; Akarsu-Ayazoglu, Tulin; Pranskunas, Andrius; Hollenberg, Steven; Balestra, Gianmarco; van Iterson, Mat; van der Voort, Peter H. J.; Sadaka, Farid; Minto, Gary; Aypar, Ulku; Hurtado, F. Javier; Martinelli, Giampaolo; Payen, Didier; van Haren, Frank; Holley, Anthony; Pattnaik, Rajyabardhan; Gomez, Hernando; Mehta, Ravindra L.; Rodriguez, Alejandro H.; Ruiz, Carolina; Canales, Héctor S.; Duranteau, Jacques; Spronk, Peter E.; Jhanji, Shaman; Hubble, Sheena; Chierego, Marialuisa; Jung, Christian; Martin, Daniel; Sorbara, Carlo; Tijssen, Jan G. P.; Bakker, Jan; Ince, Can; Koopmans, M.; van Iterson, M.; van der Voort, P. H. J.; Bakker, J.; van Bommel, J.; Ruiz, C.; Hernandez, G.; Machado, F. R.; Bafi, A. T.; Dubin, A.; Kanoore Edul, V. S.; Canales, H. S.; Hurtado, F. J.; Lacuesta, G.; Baz, M.; Hollenberg, S. M.; Patel, U.; Shapiro, N. I.; Gomez, H.; Simon, P.; Pinsky, M.; Sadaka, F. G.; Krause, K.; Mehta, R.; Jung, C.; Fries, M.; Pearse, R. M.; Smith, A.; Martin, D. S.; Meale, P.; Jhanji, S.; Minto, G.; Lai, C.; Ferguson, C.; McMillan, H.; Quintrell, T.; Sair, M.; Martinelli, G.; Lombrano, M.; Hubble, S. M. A.; Thorn, C.; Rodriguez, A. H.; Martin-Loeches, I.; van Haren, F. M. P.; Pranskunas, A.; Pilvinis, V.; Donati, A.; Sorbara, C.; Forti, A.; Comin, A.; Chierego, M. L.; Pellis, T.; Holley, A.; Paratz, J.; Duranteau, J.; Harrois, A.; Payen, D.; Legrand, M.; Bucher, E.; Pattnaik, R.; Dondorp, A. M.; Herdman, M. T.; Aypar, U.; Ayhan, B.; Ayazoglu-Akarsu, T.

    2015-01-01

    Microcirculatory alterations are associated with adverse outcome in subsets of critically ill patients. The prevalence and significance of microcirculatory alterations in the general ICU population are unknown. We studied the prevalence of microcirculatory alterations in a heterogeneous ICU

  10. 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.

  11. 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

  12. 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.

  13. 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.

  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. 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.

  16. Lens refracting cost effective photovoltaic solar energy concentrating systems

    International Nuclear Information System (INIS)

    Pilawjian, G.A.

    2014-01-01

    The overall cost reduction task is studied for photovoltaic (PV) solar energy systems. For that purpose, a new, cost effective lens refracting system is developed. The concentrating system consists of Fresnel lenses placed under different facet angles refracting the sun light onto the solar cells placed along a line. The developed photovoltaic concentrating system uses the mathematical model of Fresnel lens concentrating optics for photovoltaic systems used to optimize the system by cost. A computer program FLCPVSys2.1 for the new concentrating system is developed allowing to design a photovoltaic system of the required power with the minimum cost. The program can be used for designing a cost effective photovoltaic solar concentrating system

  17. MICROCIRCULATORY ISCHEMIA AND STATINS: LESSONS OF INTERVENTION CARDIOLOGY

    Directory of Open Access Journals (Sweden)

    An. A. Alexandrov

    2015-12-01

    Full Text Available Review is devoted to the pathogenesis of microcirculatory ischemia. Microcirculatory dysfunction has been identified in different groups of patients including syndrome X, diabetes mellitus 2 type, coronary heart disease. In coronary patients after transluminal angioplasty microcirculatory dysfunction is the reason of phenomenon of “non-reflow”. In result the procedure of revascularization is less effective. Therapy by statins can be beneficial for patients with microcirculatory ischemia.

  18. 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...

  19. Creative optomechanical tolerancing in lens systems

    Science.gov (United States)

    Lee, Kim H.; Yoon, Youngshik; Maxwell, Jonathan

    1998-09-01

    The interface between optical design and fine-mechanical design is a creatively fertile stage in the design of an optical system. The optical designer learns `What the system is all about' and the fine-mechanical engineer is liberated creatively by finding out what the priorities are. On the other hand, optical tolerancing as a discipline, which is an attractive mix of optical physics at one end and hard-nosed mechanical pragmatism at the other, has a relatively fragmented literature. It is the purpose of this paper to (1) Point out some cultural contrasts between optical engineers, mechanical engineers and physicists in this context, (2) To present a new method of displaying the optical surface sensitivities so that one may identify datum surfaces in an intuitive way and (3) To summarize some useful formulae which provide a key to the mounting of optical components. Together these three aspects illustrate the scenery of this fertile terrain.

  20. 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.

  1. Study Design of the Microcirculatory Shock Occurrence in Acutely Ill Patients (microSOAP: an International Multicenter Observational Study of Sublingual Microcirculatory Alterations in Intensive Care Patients

    Directory of Open Access Journals (Sweden)

    Namkje A. R. Vellinga

    2012-01-01

    Full Text Available Objective. Sublingual microcirculatory alterations are associated with an adverse prognosis in several critical illness subgroups. Up to now, single-center studies have reported on sublingual microcirculatory alterations in ICU patient subgroups, but an extensive evaluation of the prevalence of these alterations is lacking. We present the study design of an international multicenter observational study to investigate the prevalence of microcirculatory alterations in critically ill: the Microcirculatory Shock Occurrence in Acutely ill Patients (microSOAP. Methods. 36 ICU’s worldwide have participated in this study aiming for inclusion of over 500 evaluable patients. To enable communication and data collection, a website, an Open Clinica 3.0 database, and image uploading software have been designed. A one-session assessment of the sublingual microcirculation using Sidestream Dark Field imaging and data collection on patient characteristics has been performed in every ICU patient >18 years, regardless of underlying disease. Statistical analysis will provide insight in the prevalence and severity of sublingual alterations, its relation to systemic hemodynamic variables, disease, therapy, and outcome. Conclusion. This study will be the largest microcirculation study ever performed. It is expected that this study will also establish a basis for future studies related to the microcirculation in critically ill.

  2. Study Design of the Microcirculatory Shock Occurrence in Acutely Ill Patients (microSOAP): an International Multicenter Observational Study of Sublingual Microcirculatory Alterations in Intensive Care Patients

    Science.gov (United States)

    Vellinga, Namkje A. R.; Boerma, E. Christiaan; Koopmans, Matty; Donati, Abele; Dubin, Arnaldo; Shapiro, Nathan I.; Pearse, Rupert M.; Bakker, Jan; Ince, Can

    2012-01-01

    Objective. Sublingual microcirculatory alterations are associated with an adverse prognosis in several critical illness subgroups. Up to now, single-center studies have reported on sublingual microcirculatory alterations in ICU patient subgroups, but an extensive evaluation of the prevalence of these alterations is lacking. We present the study design of an international multicenter observational study to investigate the prevalence of microcirculatory alterations in critically ill: the Microcirculatory Shock Occurrence in Acutely ill Patients (microSOAP). Methods. 36 ICU's worldwide have participated in this study aiming for inclusion of over 500 evaluable patients. To enable communication and data collection, a website, an Open Clinica 3.0 database, and image uploading software have been designed. A one-session assessment of the sublingual microcirculation using Sidestream Dark Field imaging and data collection on patient characteristics has been performed in every ICU patient >18 years, regardless of underlying disease. Statistical analysis will provide insight in the prevalence and severity of sublingual alterations, its relation to systemic hemodynamic variables, disease, therapy, and outcome. Conclusion. This study will be the largest microcirculation study ever performed. It is expected that this study will also establish a basis for future studies related to the microcirculation in critically ill. PMID:22666566

  3. Highly sensitive straightness measurement system using a ball-lens

    International Nuclear Information System (INIS)

    Lee, Minho; Yang, Hyun-Ik; Cho, Nahm-Gyoo

    2016-01-01

    In this paper, a new and simple optical technique to accurately measure the straightness errors of a linear stage is proposed. To improve the performance, including the measurement sensitivity and resolution of the measurement system, and to simultaneously measure two-dimensional straightness errors (2D straightness errors), an optical system was designed using a laser, a retro-reflector, a ball-lens, and a two-dimensional position sensitive detector (2D PSD). The characteristics of the measurement system were analytically and experimentally investigated. A prototype measurement system was manufactured based on the investigated results, and the performances of this system have been tested. The measuring performance of the system was easily improved by about 12 times using the proposed technique and it can be further improved. It is shown that the proposed technique can easily and effectively improve the performance of a conventional straightness measurement system based on the geometric optical method using a PSD. (paper)

  4. Intestinal microcirculatory dysfunction and neonatal necrotizing enterocolitis.

    Science.gov (United States)

    Zhang, Hong-yi; Wang, Fang; Feng, Jie-xiong

    2013-01-01

    Based on the observation that coagulation necrosis occurs in the majority of neonatal necrotizing enterocolitis (NEC) patients, it is clear that intestinal ischemia is a contributing factor to the pathogenesis of NEC. However, the published studies regarding the role of intestinal ischemia in NEC are controversial. The aim of this paper is to review the current studies regarding intestinal microcirculatory dysfunction and NEC, and try to elucidate the exact role of intestinal microcirculatory dysfunction in NEC. The studies cited in this review were mainly obtained from articles listed in Medline and PubMed. The search terms used were "intestinal microcirculatory dysfunction" and "neonatal necrotizing enterocolitis". Mainly original milestone articles and critical reviews written by major pioneer investigators in the field were selected. Immature regulatory control of mesentery circulation makes the neonatal intestinal microvasculature vulnerable. When neonates are subjected to stress, endothelial cell dysfunction occurs and results in vasoconstriction of arterioles, inflammatory cell infiltration and activation in venules, and endothelial barrier disruption in capillaries. The compromised vasculature increases circulation resistance and therefore decreases intestinal perfusion, and may eventually progress to intestinal necrosis. Intestinal ischemia plays an important role through the whole course of NEC. New therapeutic agents targeting intestinal ischemia, like HB-EGF, are promising therapeutic agents for the treatment of NEC.

  5. Sublingual microcirculatory changes during high-volume hemofiltration in hyperdynamic septic shock patients.

    Science.gov (United States)

    Ruiz, Carolina; Hernandez, Glenn; Godoy, Cristian; Downey, Patricio; Andresen, Max; Bruhn, Alejandro

    2010-01-01

    Previous studies have suggested that high volume hemofiltration (HVHF) may contribute to revert hypotension in severe hyperdynamic septic shock patients. However, arterial pressure stabilization occurs due to an increase in systemic vascular resistance, which could eventually compromise microcirculatory blood flow and perfusion. The goal of this study was to determine if HVHF deteriorates sublingual microcirculation in severe hyperdynamic septic shock patients. This was a prospective, non-randomized study at a 16-bed, medical-surgical intensive care unit of a university hospital. We included 12 severe hyperdynamic septic shock patients (norepinephrine requirements > 0.3 μg/kg/min and cardiac index > 3.0 L/min/m2) who underwent a 12-hour HVHF as a rescue therapy according to a predefined algorithm. Sublingual microcirculation (Microscan for NTSC, Microvision Medical), systemic hemodynamics and perfusion parameters were assessed at baseline, at 12 hours of HVHF, and 6 hours after stopping HVHF. Microcirculatory flow index increased after 12 hours of HVHF and this increase persisted 6 hours after stopping HVHF. A similar trend was observed for the proportion of perfused microvessels. The increase in microcirculatory blood flow was inversely correlated with baseline levels. There was no significant change in microvascular density or heterogeneity during or after HVHF. Mean arterial pressure and systemic vascular resistance increased while lactate levels decreased after the 12-hour HVHF. The use of HVHF as a rescue therapy in patients with severe hyperdynamic septic shock does not deteriorate sublingual microcirculatory blood flow despite the increase in systemic vascular resistance.

  6. The NSLS-II Multilayer Laue Lens Deposition System

    International Nuclear Information System (INIS)

    Conley, R.; Bouet, N.; Biancarosa, J.; Shen, Q.; Boas, L.; Feraca, J.; Rosenbaum, L.

    2009-01-01

    The NSLS-II(1) program has a requirement for an unprecedented level of x-ray nanofocusing and has selected the wedged multilayer Laue lens(2,3) (MLL) as the optic of choice to meet this goal. In order to fabricate the MLL a deposition system is required that is capable of depositing depth-graded and laterally-graded multilayers with precise thickness control over many thousands of layers, with total film growth in one run up to 100 m thick or greater. This machine design expounds on the positive features of a rotary deposition system(4) constructed previously for MLLs and will contain multiple stationary, horizontally-oriented magnetron sources where a transport will move a substrate back and forth in a linear fashion over shaped apertures at well-defined velocities to affect a multilayer coating.

  7. A panoramic imaging system based on fish-eye lens

    Science.gov (United States)

    Wang, Ye; Hao, Chenyang

    2017-10-01

    Panoramic imaging has been closely watched as one of the major technologies of AR and VR. Mainstream panoramic imaging techniques lenses include fish-eye lenses, image splicing, and catadioptric imaging system. Meanwhile, fish-eyes are widely used in the big picture video surveillance. The advantage of fish-eye lenses is that they are easy to operate and cost less, but how to solve the image distortion of fish-eye lenses has always been a very important topic. In this paper, the image calibration algorithm of fish-eye lens is studied by comparing the method of interpolation, bilinear interpolation and double three interpolation, which are used to optimize the images.

  8. A New Optical System for Holographic Memory Applying a Finite Objective Lens

    Science.gov (United States)

    Yamakage, Yuzuru; Uno, Kazushi; Iwamura, Yasumasa; Shimokawa, Satoshi; Yoshikawa, Hiroyasu; Tezuka, Koichi; Ozaki, Kazuyuki

    2008-07-01

    We have developed a new objective lens for a holographic storage system to increase areal density. To balance focal length and working distance, we adopted a finite objective lens. By incorporating phase conjugate reproduction into the finite objective lens, we obtained practically applicable and adequate signal quality. We measured shift selectivity and the effect of crosstalk and evaluated book size, which was reduced by ca. 0.8. The areal density was estimated to increase by about 1.6 times when using the new objective lens.

  9. CLASS B2108+213 : a new wide-separation gravitational lens system

    NARCIS (Netherlands)

    McKean, JP; Browne, IWA; Jackson, NJ; Koopmans, LVE; Norbury, MA; Treu, T; York, TD; Biggs, AD; Blandford, RD; de Bruyn, AG; Fassnacht, CD; Mao, S; Myers, ST; Pearson, TJ; Phillips, PM; Readhead, ACS; Rusin, D; Wilkinson, PN

    2005-01-01

    We present observations of CLASS B2108 + 213, the widest separation gravitational lens system discovered by the Cosmic Lens All-Sky Survey. Radio imaging using the VLA at 8.46 GHz and MERLIN at 5 GHz shows two compact components separated by 4.56 arcsec with a faint third component in between which

  10. Class B0739+366 : A new two-image gravitational lens system

    NARCIS (Netherlands)

    Marlow, DR; Rusin, D; Norbury, M; Jackson, N; Browne, IWA; Wilkinson, PN; Fassnacht, CD; Myers, ST; Koopmans, LVE; Blandford, RD; Pearson, TJ; Readhead, ACS; de Bruyn, AG

    We present the discovery of CLASS B0739 + 366, a new gravitational lens system from the Cosmic Lens All-Sky Survey. Radio imaging of the source with the Very Large Array shows two compact components separated by with a flux density ratio of similar to6:1. High-resolution follow-up observations using

  11. Viewing Uganda's mental health system through a human rights lens.

    Science.gov (United States)

    Cooper, Sara; Ssebunnya, Joshua; Kigozi, Fred; Lund, Crick; Flisher, Alan

    2010-01-01

    There has been increased global concern about the human rights violations experienced by people with mental disorders. The aim of this study was to analyse Uganda's mental health care system through a human rights lens. A survey of the existing mental health system in Uganda was conducted using the WHO Assessment Instrument for Mental Health Systems. In addition, 62 interviews and six focus groups were conducted with a broad range of mental health stakeholders at the national and district levels. Despite possessing a draft mental health policy that is in line with many international human rights standards, Uganda's mental health system inadequately promotes and protects, and frequently violates the human rights of people with mental disorders. The mental health legislation is offensive and stigmatizing. It is common for people accessing mental health services to encounter physical and emotional abuse and an inadequate quality of care. Mental health services are inequitably distributed. Within Ugandan society, people with mental disorders also frequently experience widespread stigma and discrimination, and limited support. Promoting and protecting the rights of people with mental disorders has ethical and public health imperatives. A number of policy, legislative and service development initiatives are required.

  12. Lateral refraction and reflection of light polarized lenses principle. Coplanar lens systems

    International Nuclear Information System (INIS)

    Miranda, L.

    2012-01-01

    Studying the behavior of the linearly polarized light to impact a lens and in the lens itself, resulted in the discovery of a physical principle of optics, not mentioned or used so far. This phenomenon is very useful in practice. Perhaps the manifestation of the phenomenon occurs in the plane perpendicular to the road or optical axis, is due the reason that was not seen before, but it has always been there when polarized light passes through a lens. Known and mastered the principle has been manipulated for better research results, using for the first time a planar lens system, which according to the placement of the lens allows for accurate lags between the light beams ar the exits the system. (Author)

  13. Microcirculatory monitoring in septic patients: Where do we stand?

    Science.gov (United States)

    Gruartmoner, G; Mesquida, J; Ince, C

    Microcirculatory alterations play a pivotal role in sepsis-related morbidity and mortality. However, since the microcirculation has been a "black box", current hemodynamic management of septic patients is still guided by macrocirculatory parameters. In the last decades, the development of several technologies has shed some light on microcirculatory evaluation and monitoring, and the possibility of incorporating microcirculatory variables to clinical practice no longer seems to be beyond reach. The present review provides a brief summary of the current technologies for microcirculatory evaluation, and attempts to explore the potential role and benefits of their integration to the resuscitation process in critically ill septic patients. Copyright © 2016 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

  14. Symmetrical optical imaging system with bionic variable-focus lens for off-axis aberration correction

    Science.gov (United States)

    Wang, Xuan-Yin; Du, Jia-Wei; Zhu, Shi-Qiang

    2017-09-01

    A bionic variable-focus lens with symmetrical layered structure was designed to mimic the crystalline lens. An optical imaging system based on this lens and with a symmetrical structure that mimics the human eye structure was proposed. The refractive index of the bionic variable-focus lens increases from outside to inside. The two PDMS lenses with a certain thickness were designed to improve the optical performance of the optical imaging system and minimise the gravity effect of liquid. The paper presents the overall structure of the optical imaging system and the detailed description of the bionic variable-focus lens. By pumping liquid in or out of the cavity, the surface curvatures of the rear PDMS lens were varied, resulting in a change in the focal length. The focal length range of the optical imaging system was 20.71-24.87 mm. The optical performance of the optical imaging system was evaluated by imaging experiments and analysed by ray tracing simulations. On the basis of test and simulation results, the optical performance of the system was quite satisfactory. Off-axis aberrations were well corrected, and the image quality was greatly improved.

  15. Optimization of a multilayer Laue lens system for a hard x-ray nanoprobe

    International Nuclear Information System (INIS)

    Jiang, Hui; Wang, Hua; Mao, Chengwen; Li, Aiguo; He, Yan; Dong, Zhaohui; Zheng, Yi

    2014-01-01

    Detailed designs of a multilayer Laue lens system for a hard x-ray nanoprobe, including flat and wedged types, are presented, to realize nanoscale point focus and high diffraction efficiency simultaneously. The difficulty of movement and alignment for lens, aperture and sample are considered in the optimization process. Considering the practical requirements of future experiments, the features of the beamline and the structural imperfections, the working energy range, the beam vibration and structural errors are estimated and discussed. (paper)

  16. Computerized method and system for designing an aerodynamic focusing lens stack

    Science.gov (United States)

    Gard, Eric [San Francisco, CA; Riot, Vincent [Oakland, CA; Coffee, Keith [Diablo Grande, CA; Woods, Bruce [Livermore, CA; Tobias, Herbert [Kensington, CA; Birch, Jim [Albany, CA; Weisgraber, Todd [Brentwood, CA

    2011-11-22

    A computerized method and system for designing an aerodynamic focusing lens stack, using input from a designer related to, for example, particle size range to be considered, characteristics of the gas to be flowed through the system, the upstream temperature and pressure at the top of a first focusing lens, the flow rate through the aerodynamic focusing lens stack equivalent at atmosphere pressure; and a Stokes number range. Based on the design parameters, the method and system determines the total number of focusing lenses and their respective orifice diameters required to focus the particle size range to be considered, by first calculating for the orifice diameter of the first focusing lens in the Stokes formula, and then using that value to determine, in iterative fashion, intermediate flow values which are themselves used to determine the orifice diameters of each succeeding focusing lens in the stack design, with the results being output to a designer. In addition, the Reynolds numbers associated with each focusing lens as well as exit nozzle size may also be determined to enhance the stack design.

  17. Single-stage quintuplet for upgrading triplet based lens system: Simulation for Atomki microprobe

    Science.gov (United States)

    Ponomarov, Artem; Rajta, Istvan; Nagy, Gyula; Romanenko, Oleksandr V.

    2017-08-01

    Among different configurations of lens systems for nuclear microprobes, the most common one is a triplet of magnetic quadrupole lenses. Nowadays, microanalysis and material modification will undoubtedly benefit from an improvement in spatial resolution. This work presents the results of simulations for improvement of the Oxford Triplet lens system at the Atomki microprobe with consideration of its system parameters and measured beam brightness distribution. For this purpose, an additional single-unit doublet of lenses with two power supplies was introduced. Using earlier developed methods, such a quintuplet system was optimized in order to determine the parameters which provided the highest resolution for different current operational modes with the same microprobe geometry. The tolerances for lens positioning accuracy were also calculated. The obtained quintuplet parameters indicate a resolution improvement for the Atomki microprobe compared to the Oxford Triplet system and these results validate further experimental testing of the proposed quintuplet.

  18. [Contact lens dynamometry influences the systemic blood circulation: clinical significance].

    Science.gov (United States)

    Rüfer, F; Köpke, B

    2014-11-01

    The diastolic and systolic pressure in the ophthalmic artery (OAPdia, OAPsys) as well as the venous pulsation pressure (VPP) can be determined by contact lens dynamometry (CLD). With these parameters, carotid artery stenosis, ocular perfusion, e.g., in glaucoma patients and the cerebrospinal pressure can be examined indirectly. In the underlying study comparative data were collected and it was investigated to what extent CLD itself leads to changes of the systemic blood pressure. In the course of a prospective trial CLD was performed in 162 eyes of 81 healthy volunteers (mean age 41.0 ± 17.3 years). VPP, OAPdia and OAPsys were measured. A mean was calculated from 5 single readings. Directly before and after CLD automated blood pressure measurements according to Riva-Rocci (RR) and the heart rate were obtained in both arms. In the entire group, the mean VPP was 21 ± 9 mmHg on the right side and 19 ± 8 mmHg on the left side. The mean OAPdia was 60 ± 14 mmHg on the right and 67 ± 14 mmHg on the left side. The mean OAPsys was 91 ± 17 and 101 ± 21 mmHg, respectively. The mean variation coefficient from 5 single readings was 13/16 % for VPP (right/left), 7.4/8.2 % for OAPdia and 6.2/6.2 % for OAPsys. The difference between right and left eyes concerning OAPdia and OAPsys was statistically significant (Wilcoxon test; p < 0.001). VPP and OAPsys were not correlated with age, OAPdia showed a weak correlation with age on the right side (Spearman R = 0.23; p = 0.03). Blood pressure (RR) dropped from a mean 137/84 to 135/82 mmHg in the right arm and from 135/84 to 132/83 mmHg in the left arm. The change of the diastolic values of the right side and of the systolic values of the left side reached statistical significance (p < 0.05). The difference of the systolic blood pressure and the heart rate before and after CLD were weakly correlated (Spearman R = - 0.28; p = 0.01). The extent of the systemic

  19. Construction of a 300-keV compact ion microbeam system with a three-stage acceleration lens

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Yasuyuki, E-mail: ishii.yasuyuki@jaea.go.jp; Ohkubo, Takeru; Kojima, Takuji; Kamiya, Tomihiro

    2014-08-01

    Hydrogen ion microbeams were experimentally formed at beam energies below 150 keV using a 300-keV compact microbeam system that was constructed at the Japan Atomic Energy Agency. This paper is a preliminary report on the performance of the three-stage acceleration lens used in the compact microbeam system. This system consists of a three-stage acceleration lens and a plasma-type ion source. Since the three-stage acceleration lens was designed to simultaneously accelerate and focus the ion beam, the compact microbeam system is only about 1-m high and can be placed in a small experimental room. To evaluate the effectiveness of the three-stage acceleration lens, experimentally measured beam sizes are compared with theoretically calculated ones. The calculated and measured beam sizes were consistent within 10%. This shows that the three-stage acceleration lens is effective as a focusing lens for forming microbeams.

  20. Microcirculatory alterations after orthotopic pig-to-baboon heart transplantation.

    Science.gov (United States)

    Bauer, Andreas; Renz, Vivian; Baschnegger, Heiko; Abicht, Jan-Michael; Beiras-Fernandez, Andres; Brenner, Paolo; Thein, Eckart; Schmoeckel, Michael; Reichart, Bruno; Christ, Frank

    2011-01-01

    Whilst macrohemodynamic function of porcine xenografts transplanted into baboons has been assessed perioperatively, the ability of the xenograft to maintain systemic microcirculatory perfusion has not been investigated after pig-to-baboon xenotransplantation so far. We investigated the sublingual microcirculation of six baboons undergoing orthotopic transplantation of hCD46-transgenic pig hearts using orthogonal polarization spectral imaging. Microvascular measurements were performed after induction of anesthesia, in the early phase of cardiopulmonary bypass (CPB), during reperfusion of the porcine heart and 1 h after the xenograft had resumed its life-supporting function. Microvascular blood flow was analyzed semiquantitatively and the number of visualized cell-to-cell interactions was counted. The proportion of continuously perfused microvessels was 97 (96 to 97) % at baseline and 95 (94 to 97) % in the early phase of CPB. It decreased significantly (P pig-to-baboon heart transplantation, despite systemic hemodynamic parameters being well maintained by the porcine xenograft. These changes are moderate but persist after termination of CPB. Further studies need to elucidate whether these changes are transient or add to the mortality associated with cardiac xenotransplantation. © 2011 John Wiley & Sons A/S.

  1. Millimeter Wave Imaging System Using Monopole Antenna with Cylindrical Reflector and Silicon Lens

    Science.gov (United States)

    Mizuno, Maya; Fukunaga, Kaori; Suzuki, Masaki; Saito, Shingo; Fujii, Katsumi; Hosako, Iwao; Yamanaka, Yukio

    2011-04-01

    We built a reflection imaging system that uses a monopole antenna with a cylindrical reflector and silicon semi-spherical lens for millimeter waves to identify detachments of alabaster from support material such as wood and stone, which can be subject to painting deterioration. Based on the electric field property near the monopole antenna in the system and the lens effect, the system was able to clearly image a test sample made of 2-mm width aluminium tape, which was placed within a range of approximately 10 mm from the lens. In practical imaging testing using a detachment model, which consists of alabaster and wood plating, the result also showed the possibility of observing slight detachment of the alabaster from the wood more easily than an imaging with large numerical aperture.

  2. Fast Tomography Imaging System for Material Surface Based on Doublet-cylinder-lens in Intelligent OCT

    Directory of Open Access Journals (Sweden)

    Xu Shijun

    2017-01-01

    Full Text Available A fast lateral line-scan mode in OCT was investigated. The elimination of spherical aberration, the beam mode and the focus of doublet-cylinder-lens, were theoretically analyzed. The parameters and signal characteristics of the confocus microscopy system with doublet-cylinder-lens were analyzed and simulated. The relation between the transverse resolution and the numerical aperture and the depth of focus (DOF was discussed in the OCT. Our results show that the spherical aberration and the sine aberration are effectively eliminated in the doublet-cylinder-lens with K9-ZF2 glass. The beam is uniformly focused on the arc-sagitta-plane of cylinder lens, and the parallel interference pattern with axial symmetry is in favor of improving transverse resolution. The transverse resolution depends upon the numerical aperture and the DOF. The scanning velocity of doublet-cylinder-lens confocus microscopy system is 103 times faster than the traditional spot-scan, while the transverse resolution is 15μm and the constraints of aperture 50.8 mm. This advanced system will be valuable in real-time imaging to material surface.

  3. A new quadruple gravitational lens system : CLASS B0128+437

    NARCIS (Netherlands)

    Phillips, PM; Norbury, MA; Koopmans, LVE; Browne, IWA; Jackson, NJ; Wilkinson, PN; Biggs, AD; Blandford, RD; de Bruyn, AG; Fassnacht, CD; Helbig, P; Mao, S; Marlow, DR; Myers, ST; Pearson, TJ; Readhead, ACS; Rusin, D; Xanthopoulos, E

    2000-01-01

    High-resolution MERLIN observations of a newly discovered four-image gravitational lens system, B0128+437, are presented. The system was found after a careful re-analysis of the entire CLASS data set. The MERLIN observations resolve four components in a characteristic quadruple-image configuration;

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

    Directory of Open Access Journals (Sweden)

    Mauro Waiswol

    2009-03-01

    Full Text Available 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 from the pupillary area. Thirty eyes underwent cataract extraction (“dry” aspiration with endocapsular ring and in-the-bag intraocular lens (IOL implantation. Twenty-one eyes underwent cataract extraction (“dry” aspiration with scleral fixation of the IOL. The predictive value of the LSGS was assessed by analyzing the post-operative outcomes, including visual acuity (VA, endothelial cell loss, and complications for each grade on the grading system. Rresults: Patients were classified into grade 1 (19.6%, grade 2 (51% and grade 3 (29.4%. Post-operative VA was lower for eyes with larger degrees of subluxation. The higher the subluxation grade, the higher the endothelial cell loss, as well as, the frequency of vitreous loss and surgical time. Higher subluxation grades prevented optimal surgical outcomes with endocapsular ring and in-the-bag IOL implantation. Cconclusions: The LSGS provides an estimate of the surgical success of ectopia lentis. Adequate standardization of lens subluxation is crucial for understanding studies dealing with the surgical correction of this disorder.

  5. Single-lens 3D digital image correlation system based on a bilateral telecentric lens and a bi-prism: validation and application.

    Science.gov (United States)

    Wu, Lifu; Zhu, Jianguo; Xie, Huimin

    2015-09-10

    By using the principle of stereovision, 3D digital image correlation (3D-DIC) can determine the 3D morphology and deformation of a target and has been widely used in experimental mechanics as a noncontact 3D measurement technique. To eliminate the limitations of the conventional 3D-DIC system, this study proposes a calibration-free single-lens 3D-DIC system based on a bilateral telecentric lens and a bi-prism. The performance of the proposed system is verified by tests of rigid-body translation along the out-of-plane direction. As a comparison, the same rigid-body translations are measured using a single-entocentric-lens 3D-DIC system. The results show that the measurement accuracy of the proposed system is higher than that of the entocentric-lens-based one. As an application, the proposed system is used to measure the thermal linear expansion of a ceramic plate at elevated temperatures. The reasonable measurement results verify its applicability in deformation measurements, even in high-temperature environments.

  6. Student Satisfaction with Learning Management Systems: A Lens of Critical Success Factors

    Science.gov (United States)

    Naveh, Gali; Tubin, Dorit; Pliskin, Nava

    2012-01-01

    Institutions of higher education have invested heavily in learning management systems (LMS) for creating course websites. Yet, how to assess LMS effectiveness is not fully agreed upon. Based on institutional theory, this article considers student satisfaction as indicative of LMS success and proposes a lens of critical success factors (CSF) as a…

  7. Biaxial-Type Concentrated Solar Tracking System with a Fresnel Lens for Solar-Thermal Applications

    OpenAIRE

    Tsung Chieh Cheng; Chao Kai Yang; I Lin

    2016-01-01

    In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately main...

  8. Microcirculatory monitoring in septic patients: Where do we stand?

    NARCIS (Netherlands)

    Gruartmoner, G.; Mesquida, J.; Ince, C.

    2017-01-01

    Microcirculatory alterations play a pivotal role in sepsis-related morbidity and mortality. However, since the microcirculation has been a "black box", current hemodynamic management of septic patients is still guided by nnacrocirculatory parameters. In the last decades, the development of several

  9. Microcirculatory Detrusor Changes in Medicinally Denervated Bladder Patients Scientific

    Directory of Open Access Journals (Sweden)

    I.R. Valiyev

    2009-09-01

    Full Text Available In the present article the results of the study of microcirculation in abnormal urinary bladder detrusor are reported. The neurotoxic effect of botulinic toxin has been shown. The dynamics of microcirculatory changes in detrusor under the action of botulinic toxin has been evaluated

  10. The use of contact lens telescopic systems in low vision rehabilitation.

    Science.gov (United States)

    Vincent, Stephen J

    2017-06-01

    Refracting telescopes are afocal compound optical systems consisting of two lenses that produce an apparent magnification of the retinal image. They are routinely used in visual rehabilitation in the form of monocular or binocular hand held low vision aids, and head or spectacle-mounted devices to improve distance visual acuity, and with slight modifications, to enhance acuity for near and intermediate tasks. Since the advent of ground glass haptic lenses in the 1930's, contact lenses have been employed as a useful refracting element of telescopic systems; primarily as a mobile ocular lens (the eyepiece), that moves with the eye. Telescopes which incorporate a contact lens eyepiece significantly improve the weight, comesis, and field of view compared to traditional spectacle-mounted telescopes, in addition to potential related psycho-social benefits. This review summarises the underlying optics and use of contact lenses to provide telescopic magnification from the era of Descartes, to Dallos, and the present day. The limitations and clinical challenges associated with such devices are discussed, along with the potential future use of reflecting telescopes incorporated within scleral lenses and tactile contact lens systems in low vision rehabilitation. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  11. Design study for a 16x zoom lens system for visible surveillance camera

    Science.gov (United States)

    Vella, Anthony; Li, Heng; Zhao, Yang; Trumper, Isaac; Gandara-Montano, Gustavo A.; Xu, Di; Nikolov, Daniel K.; Chen, Changchen; Brown, Nicolas S.; Guevara-Torres, Andres; Jung, Hae Won; Reimers, Jacob; Bentley, Julie

    2015-09-01

    *avella@ur.rochester.edu Design study for a 16x zoom lens system for visible surveillance camera Anthony Vella*, Heng Li, Yang Zhao, Isaac Trumper, Gustavo A. Gandara-Montano, Di Xu, Daniel K. Nikolov, Changchen Chen, Nicolas S. Brown, Andres Guevara-Torres, Hae Won Jung, Jacob Reimers, Julie Bentley The Institute of Optics, University of Rochester, Wilmot Building, 275 Hutchison Rd, Rochester, NY, USA 14627-0186 ABSTRACT High zoom ratio zoom lenses have extensive applications in broadcasting, cinema, and surveillance. Here, we present a design study on a 16x zoom lens with 4 groups (including two internal moving groups), designed for, but not limited to, a visible spectrum surveillance camera. Fifteen different solutions were discovered with nearly diffraction limited performance, using PNPX or PNNP design forms with the stop located in either the third or fourth group. Some interesting patterns and trends in the summarized results include the following: (a) in designs with such a large zoom ratio, the potential of locating the aperture stop in the front half of the system is limited, with ray height variations through zoom necessitating a very large lens diameter; (b) in many cases, the lens zoom motion has significant freedom to vary due to near zero total power in the middle two groups; and (c) we discuss the trade-offs between zoom configuration, stop location, packaging factors, and zoom group aberration sensitivity.

  12. GOLDEN GRAVITATIONAL LENSING SYSTEMS FROM THE SLOAN LENS ACS SURVEY. I. SDSS J1538+5817: ONE LENS FOR TWO SOURCES ,

    International Nuclear Information System (INIS)

    Grillo, C.; Seitz, S.; Bender, R.; Eichner, T.; Bauer, A.; Lombardi, M.; Gobat, R.

    2010-01-01

    We present a gravitational lensing and photometric study of the exceptional strong lensing system SDSS J1538+5817, identified by the Sloan Lens Advanced Camera for Survey. The lens is a luminous elliptical galaxy at redshift z l = 0.143. Using Hubble Space Telescope public images obtained with two different filters, the presence of two background sources lensed, respectively, into an Einstein ring and a double system is ascertained. Our new spectroscopic observations, performed at the Nordic Optical Telescope, reveal unequivocally that the two sources are located at the same redshift z s = 0.531. We investigate the total (luminous and dark) mass distribution of the lens between 1 and 4 kpc from the galaxy center by means of parametric and non-parametric lensing codes that describe the multiple images as point-like objects. Bootstrapping and Bayesian analyses are performed to determine the uncertainties on the quantities relevant to the lens mass characterization. Several disparate lensing models provide results that are consistent, given the errors, with those obtained from the best-fit model of the lens mass distribution in terms of a singular power-law ellipsoid model. In particular, the lensing models agree on: (1) reproducing accurately the observed positions of the images; (2) predicting a nearly axisymmetric total mass distribution, centered and oriented as the light distribution; (3) measuring a value of 8.11 +0.27 -0.59 x 10 10 M sun for the total mass projected within the Einstein radius of 2.5 kpc; and (4) estimating a total mass density profile slightly steeper than an isothermal one (ρ(r)∝r -2.33 +0.43 -0.20 ). A fit of the Sloan Digital Sky Survey multicolor photometry with composite stellar population models provides a value of 20 +1 -4 x 10 10 M sun for the total mass of the galaxy in the form of stars and of 0.9 +0.1 -0.2 for the fraction of projected luminous over total mass enclosed inside the Einstein radius. By combining lensing (total) and

  13. Non-Linear Beam Transport System for the LENS 7 MeV Proton Beam

    CERN Document Server

    Jones, William P; Derenchuk, Vladimir Peter; Rinckel, Thomas; Solberg, Keith

    2005-01-01

    A beam transport system has been designed to carry a high-intensity low-emittance proton beam from the exit of the RFQ-DTL acceleration system of the Indiana University Low Energy Neutron System (LENS)* to the neutron production target. The goal of the design was to provide a beam of uniform density over a 3cm by 3cm area at the target. Two octupole magnets** are employed in the beam line to provide the necessary beam phase space manipulations to achieve this goal. First order calculations were done using TRANSPORT and second order calculations have been performed using TURTLE. Second order simulations have been done using both a Gaussian beam distribution and a particle set generated by calculations of beam transport through the RFQ-DTL using PARMILA. Comparison of the design characteristics with initial measurements from the LENS commissioning process will be made.

  14. Corneo-scleral contact lens in a piggyback system for keratoconus: A case report.

    Science.gov (United States)

    Porcar, Esteban; Montalt, Juan Carlos; España-Gregori, Enrique; Peris-Martínez, Cristina

    2017-06-01

    We describe a case of fitting a corneo-scleral contact lens with a multi-aspheric geometry design (MAGD CScL) on top of a daily silicone hydrogel lens (piggyback system) for keratoconus management. A 48-year-old man using soft toric contact lenses required an improvement in the unsatisfactory quality of his vision. He presented with bilateral asymmetric keratoconus with high myopia in the right eye (RE) and severe myopia in the left eye (LE). In addition, he had low vision in his LE because of a maculopathy. He was fitted with MAGD CScL to correct his irregular astigmatism. A diagnostic trial set was used in the fitting process and the patient was assessed according to a standardised fitting methodology. Visual acuity, corneal topography and contrast sensitivity were evaluated. The follow-up period was 1year. The best spectacle-corrected visual acuity was 0.5 logMAR for the RE with -10 D/-5 D×60° and 2 logMAR for the LE with -20 D/-3 D×105°. After fitting MAGD CScL, visual acuity improved significantly to 0.1 logMAR for the RE and 1.3 logMAR for the LE, as well as contrast sensitivity. The fitting parameters of the base curve, diameter, and power were 7.05mm, 12.60mm, -18.50 D and 7.15mm, 12.60mm, -19 D for the RE and LE, respectively. Optimal fitting characteristics were found in terms of lens position and lens movement. To increase the time of MAGD CScL wear, they piggybacked on daily silicone hydrogel lenses of low power (-0.5 D). The patient reported being comfortable with this piggyback system for approximately 15h a day. After 1year of using the piggyback system, visual quality and wearing time were maintained. In addition, no adverse ocular effects were found during this period. This case report shows that in this patient a MAGD CScL could be fitted successfully on a daily silicone hydrogel lens in a piggyback system for keratoconus management, providing good visual quality along with prolonged use times and without adverse effects on the cornea

  15. A wide-FoV athermalized infrared imaging system with a two-element lens

    Science.gov (United States)

    Feng, Bin; Shi, Zelin; Zhao, Yaohong; Liu, Haizheng; Liu, Li

    2017-12-01

    For infrared imaging systems to achieve wide field of view (FoV), wide operating temperature and low weight, this work designs a wide-FoV athermalized infrared imaging system (AIIS) with a two-element lens. Its principle, design, manufacture, measurement and performance validation are successively discussed. The two-element lens contains four surfaces, where three aspheric surfaces are introduced to reduce optical off-axis aberrations and a cubic surface is introduced to achieve athermalization. The key coding mask containing an aspheric surface and a cubic surface is manufactured by nano-metric machining of ion implanted material (NiIM). Experimental results validate that our wide-FoV wavefront coding AIIS has a full FoV of 26.10° and an operating temperature over -20 °C to +70 °C.

  16. Frequency Invariant Beam Steering for Short-Pulse Systems with a Rotman Lens

    Directory of Open Access Journals (Sweden)

    Andreas Lambrecht

    2010-01-01

    Full Text Available A promising approach for beam steering of high-voltage transient signals for HPEM-systems (High Power Electro Magnetic is presented. The inherent capability of the Rotman lens to provide true time delays is used to develop a prototype beam steering device for an antielectronics HPEM system in the frequency range from 350 MHz to 5 GHz. Results of analytical calculations, simulations, and measurements from a hardware prototype are presented. The detailed mechanical setup of the Rotman lens is presented. Additionally the output pulses are investigated when inputting a Gaussian-like transient signal. Then time domain measures of quality (full width at half maximum, ringing, delay spread, maximum of transfer function are investigated for these output transients, and the simulation and measurement results are compared. A concluding analysis of the realizable time domain array pattern shows the radiated pulse form.

  17. Conceptualizing HRM system strength through a cross-cultural lens

    NARCIS (Netherlands)

    Farndale, E.; Sanders, K.

    2017-01-01

    To date, literature on HRM system strength has been largely universalistic, that is, it has not considered the implications of context. This is problematic as it overlooks a more detailed exploration of the outcomes of HRM system strength in different situational settings. Adopting a contingency

  18. Time evolution of sublingual microcirculatory changes in recreational marathon runners

    OpenAIRE

    Pranskūnas, Andrius; Kiudulaitė, Inga; Šimkienė, Jūratė; Damanskytė, Diana; Pranskūnienė, Živilė; Arštikytė, Justina; Vaitkaitis, Dinas; Pilvinis, Vidas; Brazaitis, Marius

    2017-01-01

    Introduction: Marathon race transiently elevates the probability of sudden death. Also during long-distance run may occur various gastrointestinal symptoms with range from mild nausea to hemorrhagic stool. However microcirculatory nature of this disturbances is not clear. Microcirculation of sublingual mucosa is part of interest, because it is easy and noninvasively accessible, changes have relation with mortality and it is part of the upper digestive tract. Here, we evaluate changes in subli...

  19. The equity lens in the health care performance evaluation system.

    Science.gov (United States)

    Barsanti, Sara; Nuti, Sabina

    2014-01-01

    The main objective of this paper is to describe how indicators of the equity of access to health care according to socioeconomic conditions may be included in a performance evaluation system (PES) in the regional context level and in the planning and strategic control system of healthcare organisations. In particular, the paper investigates how the PES adopted, in the experience of the Tuscany region in Italy, indicators of vertical equity over time. Studies that testify inequality of access to health services often remain just a research output and are not used as targets and measurements in planning and control systems. After a brief introduction to the concept of horizontal and vertical equity in health care systems and equity measures in PES, the paper describes the 'equity process' by which selected health indicators declined by socioeconomic conditions were shared and used in the evaluation of health care institutions and in the CEOs' rewarding system, and subsequently analyses the initial results. Results on the maternal and child path and the chronicity care path not only show improvements in addressing health care inequalities, but also verify whether the health system responds appropriately to different population groups. Copyright © 2013 John Wiley & Sons, Ltd.

  20. Investigation of a metamaterial slab lens and an imaging system based on an ellipsoidal cavity.

    Science.gov (United States)

    Kordi, Mahdi; Mirsalehi, Mir Mojtaba

    2017-06-01

    A slab metamaterial lens with a refractive index of -1 is capable of producing a perfect image, since it transfers all the plane waves from the object plane to the image plane without creating any distortion in their amplitudes and phases. However, its practical implementation encounters several challenges. In this paper, a lossless slab metamaterial lens is investigated using the ray-tracing technique. We also discuss propagating waves and evanescent waves and investigate an imaging system based on an ellipsoidal cavity. It is shown that since an ellipsoidal cavity transfers the beams from one of its foci to the other with the same amplitude and phase, it acts similarly to a metamaterial slab lens of n=-1. Therefore, this structure can be used as a subwavelength resolution imaging system. Also, it does not suffer from chromatic aberration, since all the rays transmitted from one focus pass through the other independent of the wavelength. Another important advantage of this system, compared to metamaterial-based superlenses, is that it can operate at any frequency as long as the dimensions of the cavity are much larger than the wavelength.

  1. Design and optimization of multipole lens and Wien filter systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu Haoning, E-mail: haoning@mebs.co.uk [Munro' s Electron Beam Software Ltd., 14 Cornwall Gardens, London SW7 4AN (United Kingdom); Wang Liping; Rouse, John; Munro, Eric [Munro' s Electron Beam Software Ltd., 14 Cornwall Gardens, London SW7 4AN (United Kingdom)

    2011-07-21

    The differential algebra (DA) method has been employed to compute the optical properties and aberrations up to the fifth order of multipole systems containing electrostatic and magnetic round, quadrupole, hexapole and octopole lenses, and Wien filters. A new software package has been developed, which computes the geometrical and chromatic aberrations up to the fifth order by using a single DA ray trace. It also has an optimization module where a weighted set of aberrations can be minimized by the automatic adjustment of a set of user-defined system variables. In this paper, we present our new method for designing and optimizing multipole systems including Wien filters, and illustrate its application with three relevant examples.

  2. Design and optimization of multipole lens and Wien filter systems

    Science.gov (United States)

    Liu, Haoning; Wang, Liping; Rouse, John; Munro, Eric

    2011-07-01

    The differential algebra (DA) method has been employed to compute the optical properties and aberrations up to the fifth order of multipole systems containing electrostatic and magnetic round, quadrupole, hexapole and octopole lenses, and Wien filters. A new software package has been developed, which computes the geometrical and chromatic aberrations up to the fifth order by using a single DA ray trace. It also has an optimization module where a weighted set of aberrations can be minimized by the automatic adjustment of a set of user-defined system variables. In this paper, we present our new method for designing and optimizing multipole systems including Wien filters, and illustrate its application with three relevant examples.

  3. Reducing aberration effect of Fourier transform lens by modifying Fourier spectrum of diffractive optical element in beam shaping optical system.

    Science.gov (United States)

    Zhang, Fang; Zhu, Jing; Song, Qiang; Yue, Weirui; Liu, Jingdan; Wang, Jian; Situ, Guohai; Huang, Huijie

    2015-10-20

    In general, Fourier transform lenses are considered as ideal in the design algorithms of diffractive optical elements (DOEs). However, the inherent aberrations of a real Fourier transform lens disturb the far field pattern. The difference between the generated pattern and the expected design will impact the system performance. Therefore, a method for modifying the Fourier spectrum of DOEs without introducing other optical elements to reduce the aberration effect of the Fourier transform lens is proposed. By applying this method, beam shaping performance is improved markedly for the optical system with a real Fourier transform lens. The experiments carried out with a commercial Fourier transform lens give evidence for this method. The method is capable of reducing the system complexity as well as improving its performance.

  4. 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.

  5. Polarization Monitoring of the Lens System JVAS B0218+357

    Directory of Open Access Journals (Sweden)

    Andrew Biggs

    2017-10-01

    Full Text Available Monitoring of the lens system JVAS B0218+357 with the Fermi Gamma-ray Space Telescope measured a different time delay to that derived from radio observations. We have re-analysed three months of archival Very Large Array data to produce variability curves with an average sampling of one epoch per day in total flux, polarized flux and polarization position angle (PPA at 15, 8.4 and 5 GHz. The variability is particularly strong in polarized flux. Dense sampling and improved subtraction of the Einstein ring has allowed us to produce superior variability curves and a preliminary analysis has resulted in a time delay (11.5 days which agrees well with the γ -ray value. Both images of 0218+357 are subject to strong Faraday rotation and depolarization as a result of the radio waves passing through the interstellar medium of the spiral lens galaxy. Our data reveal frequency-dependent variations in the PPA that are different in each image and which must therefore result from variable Faraday rotation in the lens galaxy on timescales of a few days. Our analysis has revealed systematic errors in the polarization position angle measurements that strongly correlate with hour angle. Although we have been able to correct for these, we caution that all VLA polarization observations are potentially affected.

  6. Measurement of functional microcirculatory geometry and velocity distributions using automated image analysis

    NARCIS (Netherlands)

    Dobbe, J. G. G.; Streekstra, G. J.; Atasever, B.; van Zijderveld, R.; Ince, C.

    2008-01-01

    This study describes a new method for analyzing microcirculatory videos. It introduces algorithms for quantitative assessment of vessel length, diameter, the functional microcirculatory density distribution and red blood-cell (RBC) velocity in individual vessels as well as its distribution. The

  7. Golden Gravitational Lensing Systems from the Sloan Lens ACS Survey. I. SDSS J1538+5817: One Lens for Two Sources

    Science.gov (United States)

    Grillo, C.; Eichner, T.; Seitz, S.; Bender, R.; Lombardi, M.; Gobat, R.; Bauer, A.

    2010-02-01

    We present a gravitational lensing and photometric study of the exceptional strong lensing system SDSS J1538+5817, identified by the Sloan Lens Advanced Camera for Survey. The lens is a luminous elliptical galaxy at redshift zl = 0.143. Using Hubble Space Telescope public images obtained with two different filters, the presence of two background sources lensed, respectively, into an Einstein ring and a double system is ascertained. Our new spectroscopic observations, performed at the Nordic Optical Telescope, reveal unequivocally that the two sources are located at the same redshift zs = 0.531. We investigate the total (luminous and dark) mass distribution of the lens between 1 and 4 kpc from the galaxy center by means of parametric and non-parametric lensing codes that describe the multiple images as point-like objects. Bootstrapping and Bayesian analyses are performed to determine the uncertainties on the quantities relevant to the lens mass characterization. Several disparate lensing models provide results that are consistent, given the errors, with those obtained from the best-fit model of the lens mass distribution in terms of a singular power-law ellipsoid model. In particular, the lensing models agree on: (1) reproducing accurately the observed positions of the images; (2) predicting a nearly axisymmetric total mass distribution, centered and oriented as the light distribution; (3) measuring a value of 8.11+0.27 -0.59 × 1010 M sun for the total mass projected within the Einstein radius of 2.5 kpc; and (4) estimating a total mass density profile slightly steeper than an isothermal one (ρ (r) ∝ r^{-2.33^{+0.43}_{-0.20}}). A fit of the Sloan Digital Sky Survey multicolor photometry with composite stellar population models provides a value of 20+1 -4 × 1010 M sun for the total mass of the galaxy in the form of stars and of 0.9+0.1 -0.2 for the fraction of projected luminous over total mass enclosed inside the Einstein radius. By combining lensing (total

  8. 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.

  9. Resolution limit of probe-forming systems with magnetic quadrupole lens triplets and quadruplets

    International Nuclear Information System (INIS)

    Ponomarev, A.G.; Melnik, K.I.; Miroshnichenko, V.I.; Storizhko, V.E.; Sulkio-Cleff, B.

    2003-01-01

    Over the past decade, in MeV ion beam microanalysis efforts to achieve a spatial resolution better than 0.1 μm with a beam current of ∼100 pA have been connected with microprobes of new generation where the probe is formed by means of separated magnetic quadrupole lens structures . However, as was pointed out in , no dramatic improvements in spatial resolution have been produced so far. For better understanding of the situation the authors carried out theoretical studies of multiparameter sets of probe-forming systems based on separated triplets and quadruplets of magnetic quadrupole lenses. Comparisons were made between the highest current values attained at different systems for a given beam spot size. The maximum parasitic sextupole and octupole field components were found whose contributions to spot broadening are tolerable. It is shown that the use of modern electrostatic accelerators and precision magnetic quadrupole lenses makes it possible to eliminate the effect of chromatic aberrations and second- and third-order parasitic aberrations resulting from distortions of the quadrupole lens symmetry. Therefore probe-forming systems with triplets and quadruplets of magnetic quadrupole lenses have a lower theoretical spatial resolution limit which is restricted mainly by intrinsic spherical third-order aberrations in state-of-the-art microprobes

  10. [Mitochondrial and microcirculatory distress syndrome in the critical patient. Therapeutic implications].

    Science.gov (United States)

    Navarrete, M L; Cerdeño, M C; Serra, M C; Conejero, R

    2013-10-01

    Mitochondrial and microcirculatory distress syndrome (MMDS) can occur during systemic inflammatory response syndrome (SIRS), and is characterized by cytopathic tissue hypoxia uncorrected by oxygen transport optimization, and associated with an acquired defect in the use of oxygen and energy production in mitochondria, leading to multiple organ dysfunction (MOD). We examine the pathogenesis of MMDS, new diagnostic methods, and recent therapeutic approaches adapted to each of the three phases in the evolution of the syndrome. In the initial phase, the aim is prevention and early reversal of mitochondrial dysfunction. Once the latter is established, the aim is to restore flow of the electron chain, mitochondrial respiration, and to avoid cellular energy collapse. Finally, in the third (resolution) stage, treatment should focus on stimulating mitochondrial biogenesis and the repair or replacement of damaged mitochondria. Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  11. Lamp system with a single second-lens newly designed by using the least square method for 4 LEDs

    Science.gov (United States)

    Jo, Jae Heung; Ryu, Jae Myung; Hong, Chun Gang

    2014-05-01

    It is common for many companies to use multiple LEDs to enhance the brightness of a LED lamp and, in general, four LEDs are used in the LED lamp systems. Moreover, the second-lens must be used to obtain a straight uniform illumination from LED lights. Where four LEDs are used, four second-lenses are also assembled conventionally and those four units of second-lenses are manufactured from a single mold and assembled together with the LEDs. However, this study introduces a new method of using the Least Square Method to get a uniform illumination with the divergence angle of 40 degrees with a new single injection molded lens. Thanks to this optical design with a single lens, the assembling process of LED lamp system was simplified by eliminating the complicated assembly procedure. Also, the uniformity of illumination of this newly designed lamp system was less than 14.1%.

  12. 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 ...

  13. Research on the processing technology of medium-caliber aspheric lens in the optoelectronic integrated test system

    Science.gov (United States)

    Liu, Dan; Yu, Xin-ying; Wang, Wei

    2016-10-01

    In the optoelectronic integrated test system, surface profile and finish of the optical element are put forward higher request. Taking an aspherical quartz glass lens with a diameter of 200mm as example, taking Preston hypothesis as the theoretical basis, analyze the influence of surface quality of various process parameters, including the workpiece and the tool axis spindle speed, wheel type, concentration polishing, polishing mold species, dwell time, polishing pressure and other parameters. Using CNC method for the surface profile and surface quality of the lens were investigated. Taking profilometer measurement results as a guide, by testing and simulation analysis, process parameters were improved constantly in the process of manufacturing. Mid and high frequency error were trimmed and improved so that the surface form gradually converged to the required accuracy. The experimental results show that the final accuracy of the surface is less than 2µm and the surface finish is, which fulfils the accuracy requirement of aspherical focusing lens in optical system.

  14. Acanthamoeba keratitis: synergy between amebic and bacterial cocontaminants in contact lens care systems as a prelude to infection.

    Science.gov (United States)

    Bottone, E J; Madayag, R M; Qureshi, M N

    1992-01-01

    We encountered a patient with Acanthamoeba keratitis whose contact lens care solution contained numerous trophozoites and cysts admixed with Xanthomonas maltophilia organisms, many of which were adherent to the trophozoite surface and internalized within endocytic vacuoles. Because of this finding, we investigated the role of bacterial cocontaminants in contact lens care systems as substrates for the growth of Acanthamoeba spp. Individual cocultivation of Acanthamoeba castellanii and A. polyphaga with X. maltophilia, Flavobacterium breve, and Pseudomonas paucimobilis showed better enhancement (1.5x) of ameba growth after 96 h than that obtained in the presence of Staphylococcus aureus, S. epidermidis, and Escherichia coli, the standard cocultivation species used for isolation of amebae from clinical specimens. Our data suggest that contamination of contact lens care systems with Acanthamoeba spp. and a bacterial species capable of supporting amebic growth may be the first step in the pathogenesis of ameba-induced keratitis by the provision of large inocula of amebae. Images PMID:1401013

  15. The simulation of three-dimensional ray tracing and parameters optimization in DPL lens duct coupling system

    Science.gov (United States)

    Fan, Shuwei; Zhang, Yan; Shen, Yuting

    2010-06-01

    DPL coupling system was researched in this paper. First, the mathematic model of 3D and 2D light transmission in hollow duct was analyzed and compared. Then the 3D simulation software for all rays of the coupling system -lens duct was developed. The influence of various structural parameters of the hollow lens duct to the energy and the beam distribution were discussed with the help of developed software. The structural parameters such as the duct length, the lens radius, the size of the input and output ends were researched and were optimized to get higher efficiency and better beam distribution. Finally, the energy conversion efficiency and the beam spatial distribution of before and after optimization were compared. The results showed that the efficiency and the distribution of energy were well improved after the optimization.

  16. Design and Tests of a High-Performance Long-Wave Infrared Refractive Thermal Imager: Freeform Lens in Coaxial System

    Directory of Open Access Journals (Sweden)

    Jinjin Chen

    2017-11-01

    Full Text Available In this paper, we used a freeform lens in a long-wave, un-cooled, refractive infrared (IR thermal imager and present the design strategy and test results. This optical system is composed of only one freeform lens and several spheres. It can correct the distortion issue inherent to wide field-of-view systems more effectively, and achieve a better thermal imaging performance simultaneously compared to traditional aspheric optical lenses. Such a design model can alleviate the calculation load and cater for the demand of the ultra-precision turning on single crystal germanium. It satisfies the design idea of freeform surfaces with machining feasibility. The refractive freeform IR imager can be realized from the theoretical design to the engineering applications. The research contents of this paper are helpful for the further application of the freeform lens to a more complex cooled infrared refractive thermal imager.

  17. A new highly integrated design and novel lens system for the CSIRO/GEMOC nuclear probe

    International Nuclear Information System (INIS)

    Ryan, C.G.; Griffin, W.L.; Sie, S.H.; Cripps, G.; Suter, G.F.; Jamieson, D.N.; Ryan, C.G.; Griffin, W.L.

    1998-01-01

    The landscape of microanalysis in the geosciences has changed dramatically in the past few years, and with it the role of the Nuclear Microprobe (NMP). The emphasis of NMP applications has shifted to the advanced complementary techniques of quantitative trace-element imaging, in situ non-destructive fluid and solid inclusion analysis, light element microanalysis using PIGE, lattice location using ion micro-channeling, and to applications requiring finer spatial resolution. Recent success of a collaborative ARC bid by the National Key Centre for the Geochemical Evolution and Metallogeny of Continents (GEMOC) and the CSIRO has enabled the development of a new Nuclear Microprobe at the CSIRO designed to meet this challenge and to fully exploit the potential of the NMP in geology. The instrument and some of its features are described. It uses a novel quintuplet magnetic quadrupole lens system, computer controlled beam-shaping, high-resolution microscope optics and a close geometry detector system

  18. The impact of a preloaded intraocular lens delivery system on operating room efficiency in routine cataract surgery.

    Science.gov (United States)

    Jones, Jason J; Chu, Jeffrey; Graham, Jacob; Zaluski, Serge; Rocha, Guillermo

    2016-01-01

    The aim of this study was to evaluate the operational impact of using preloaded intraocular lens (IOL) delivery systems compared with manually loaded IOL delivery processes during routine cataract surgeries. Time and motion data, staff and surgery schedules, and cost accounting reports were collected across three sites located in the US, France, and Canada. Time and motion data were collected for manually loaded IOL processes and preloaded IOL delivery systems over four surgery days. Staff and surgery schedules and cost accounting reports were collected during the 2 months prior and after introduction of the preloaded IOL delivery system. The study included a total of 154 routine cataract surgeries across all three sites. Of these, 77 surgeries were performed using a preloaded IOL delivery system, and the remaining 77 surgeries were performed using a manual IOL delivery process. Across all three sites, use of the preloaded IOL delivery system significantly decreased mean total case time by 6.2%-12.0% (Psystem also decreased surgeon lens time, surgeon delays, and eliminated lens touches during IOL preparation. Compared to a manual IOL delivery process, use of a preloaded IOL delivery system for cataract surgery reduced total case time, total surgeon lens time, surgeon delays, and eliminated IOL touches. The time savings provided by the preloaded IOL delivery system provide an opportunity for sites to improve routine cataract surgery throughput without impacting surgeon or staff capacity.

  19. Decision Support System to Choose Digital Single Lens Camera with Simple Additive Weighting Method

    Directory of Open Access Journals (Sweden)

    Tri Pina Putri

    2016-11-01

    Full Text Available One of the technologies that evolve today is Digital Single Lens Reflex (DSLR camera. The number of products makes users have difficulties to choose the appropriate camera based on their criteria. Users may utilize several ways to help them choosing the intended camera such as using magazine, internet, and other media. This paper discusses about a web based decision support system to choose cameras by using SAW (Simple Additive Weighting method in order to make the decision process more effective and efficient. This system is expected to give recommendations about the camera which is appropriate with the user’s need and criteria based on the cost, the resolution, the feature, the ISO, and the censor. The system was implemented by using PHP and MySQL. Based on the result of questionnaire distributed to 20 respondents, 60% respondents agree that this decision support system can help users to choose the appropriate camera DSLR in accordance with the user’s need, 60% of respondents agree that this decision support system is more effective to choose DSLR camera and 75% of respondents agree that this system is more efficient. In addition, 60.55% of respondents agree that this system has met 5 Es Usability Framework.

  20. Simulation model of a new solar laser system of Fresnel lens according to real observed solar radiation data in

    Directory of Open Access Journals (Sweden)

    Yasser A. Abdel-Hadi

    2015-12-01

    Full Text Available A new simulation model of a new solar pumped laser system was tested to be run in Helwan in Egypt (latitude φ = 29°52′N, longitude λ = 31°21′E and elevation = 141 m as an example of an industrial polluted area. The system is based on concentrating the solar radiation using a Fresnel lens on a laser head fixed on a mount tracking the sun during the day and powered by a DC battery. Two cases of this model are tested; the first one is the model consisting of a Fresnel lens and a two-dimensional Compound Parabolic Concentrator (CPC, while the other is the model consisting of a Fresnel lens and a three-dimensional Compound Parabolic Concentrator (CPC. The model is fed by real actual solar radiation data taken in Helwan Solar Radiation Station at NRIAG in the various seasons in order to know the laser power got from such a system in those conditions. For the system of Fresnel lens and 2D-CPC, an average laser output power of 1.27 W in Winter, 2 W in Spring, 5 W in Summer and 4.68 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 3.24 W. For the system of Fresnel lens and 3D-CPC, an average laser output power of 3.28 W in Winter, 3.55 W in Spring, 7.56 W in Summer and 7.13 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 5.38 W.

  1. Simulation model of a new solar laser system of Fresnel lens according to real observed solar radiation data in

    Science.gov (United States)

    Abdel-Hadi, Yasser A.; Ghitas, A.; Abulwfa, A.; Sabry, M.

    2015-12-01

    A new simulation model of a new solar pumped laser system was tested to be run in Helwan in Egypt (latitude φ = 29°52‧N, longitude λ = 31°21‧E and elevation = 141 m) as an example of an industrial polluted area. The system is based on concentrating the solar radiation using a Fresnel lens on a laser head fixed on a mount tracking the sun during the day and powered by a DC battery. Two cases of this model are tested; the first one is the model consisting of a Fresnel lens and a two-dimensional Compound Parabolic Concentrator (CPC), while the other is the model consisting of a Fresnel lens and a three-dimensional Compound Parabolic Concentrator (CPC). The model is fed by real actual solar radiation data taken in Helwan Solar Radiation Station at NRIAG in the various seasons in order to know the laser power got from such a system in those conditions. For the system of Fresnel lens and 2D-CPC, an average laser output power of 1.27 W in Winter, 2 W in Spring, 5 W in Summer and 4.68 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 3.24 W. For the system of Fresnel lens and 3D-CPC, an average laser output power of 3.28 W in Winter, 3.55 W in Spring, 7.56 W in Summer and 7.13 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 5.38 W.

  2. Similar Microcirculatory Alterations in Patients with Normodynamic and Hyperdynamic Septic Shock

    NARCIS (Netherlands)

    Edul, Vanina S. Kanoore; Ince, Can; Vazquez, Alejandro Risso; Rubatto, Paolo N.; Espinoza, Emilio D. Valenzuela; Welsh, Sebastián; Enrico, Carolina; Dubin, Arnaldo

    2016-01-01

    Rationale: In normodynamic septic shock, the quantitative assessment of sublingual microcirculation has shown decreases in perfused vascular density and red blood cell velocity. However, no studies have been performed in hyperdynamic septic shock. Objectives: To characterize the microcirculatory

  3. The microcirculatory response to compensated hypovolemia in a lower body negative pressure model

    NARCIS (Netherlands)

    Bartels, Sebastiaan A.; Bezemer, Rick; Milstein, Dan M. J.; Radder, Matthijs; Lima, Alexandre; Cherpanath, Thomas G. V.; Heger, Michal; Karemaker, John M.; Ince, Can

    2011-01-01

    The objective of the present study was to test the hypothesis that controlled, adequately compensated, central hypovolemia in subjects with intact autoregulation would be associated with decreased peripheral microcirculatory diffusion and convection properties and, consequently, decreased tissue

  4. Relationship between sublingual and intestinal microcirculatory perfusion in patients with abdominal sepsis

    NARCIS (Netherlands)

    Boerma, E. Christiaan; van der Voort, Peter H. J.; Spronk, Peter E.; Ince, Can

    2007-01-01

    Objective: To evaluate the relation between sublingual and intestinal microcirculatory alterations in patients with abdominal sepsis. Design. Prospective observational study. Setting. A 23-bed mixed intensive care unit of a tertiary teaching hospital. Patients: Twenty-three patients with abdominal

  5. Quantifying bedside-derived imaging of microcirculatory abnormalities in septic patients: a prospective validation study

    NARCIS (Netherlands)

    Boerma, E. Christiaan; Mathura, Keshen R.; van der Voort, Peter H. J.; Spronk, Peter E.; Ince, Can

    2005-01-01

    INTRODUCTION: The introduction of orthogonal polarization spectral (OPS) imaging in clinical research has elucidated new perspectives on the role of microcirculatory flow abnormalities in the pathogenesis of sepsis. Essential to the process of understanding and reproducing these abnormalities is the

  6. Off-axis holographic lens spectrum-splitting photovoltaic system for direct and diffuse solar energy conversion.

    Science.gov (United States)

    Vorndran, Shelby D; Chrysler, Benjamin; Wheelwright, Brian; Angel, Roger; Holman, Zachary; Kostuk, Raymond

    2016-09-20

    This paper describes a high-efficiency, spectrum-splitting photovoltaic module that uses an off-axis volume holographic lens to focus and disperse incident solar illumination to a rectangular shaped high-bandgap indium gallium phosphide cell surrounded by strips of silicon cells. The holographic lens design allows efficient collection of both direct and diffuse illumination to maximize energy yield. We modeled the volume diffraction characteristics using rigorous coupled-wave analysis, and simulated system performance using nonsequential ray tracing and PV cell data from the literature. Under AM 1.5 illumination conditions the simulated module obtained a 30.6% conversion efficiency. This efficiency is a 19.7% relative improvement compared to the more efficient cell in the system (silicon). The module was also simulated under a typical meteorological year of direct and diffuse irradiance in Tucson, Arizona, and Seattle, Washington. Compared to a flat panel silicon module, the holographic spectrum splitting module obtained a relative improvement in energy yield of 17.1% in Tucson and 14.0% in Seattle. An experimental proof-of-concept volume holographic lens was also fabricated in dichromated gelatin to verify the main characteristics of the system. The lens obtained an average first-order diffraction efficiency of 85.4% across the aperture at 532 nm.

  7. Hydrogeology in the area of a freshwater lens in the Floridan aquifer system, northeast Seminole County, Florida

    Science.gov (United States)

    Phelps, G.G.; Rohrer, K.P.

    1987-01-01

    Northeast Seminole County, Florida, contains an isolated recharge area of the Floridan aquifer system that forms a freshwater lens completely surrounded by saline water. The freshwater lens covers an area of about 22 sq mi surrounding the town of Geneva, and generally is enclosed by the 25 ft land surface altitude contour. Thickness of the lens is about 350 ft in the center of the recharge area. The geohydrologic units in descending order consist of the post-Miocene sand and shell of the surficial aquifer; Miocene clay, sand, clay, and shell that form a leaky confining bed; and permeable Eocene limestones of the Floridan aquifer system. The freshwater lens is the result of local rainfall flushing ancient seawater from the Floridan aquifer system. Sufficient quantities of water for domestic and small public supply systems are available from the Floridan aquifer system in the Geneva area. The limiting factor for water supply in the area is the chemical quality of the water. Chloride concentrations range from < 20 mg/L in the center of the recharge area to about 5,100 mg/L near the St. Johns River southeast of Geneva. Constituents analyzed included sulfate (range 1 to 800 mg/L), hardness (range 89 to 2,076 mg/L), and iron (range 34 to 6,600 mg/L). Because the freshwater lens results entirely from local recharge, the long-term sustained freshwater yield of the aquifer in the Geneva area depends on the local recharge rate. In 1982, recharge was about 13 inches (13.8 million gal/day). Average recharge for 1941 through 1970 was estimated to be about 11 inches (11.3 million gal/day). Freshwater that recharges the aquifer in the Geneva area is either pumped out or flows north and northeast to discharge near or in the St. Johns River. Average annual outflow from the lens is about 10 in/yr. No measurable change in the size or location of the freshwater lens has occurred since studies in the early 1950's. (Lantz-PTT)

  8. Biaxial-Type Concentrated Solar Tracking System with a Fresnel Lens for Solar-Thermal Applications

    Directory of Open Access Journals (Sweden)

    Tsung Chieh Cheng

    2016-04-01

    Full Text Available In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately maintains the sun’s radiation perpendicular to the plane of the heating head. The results indicated that the position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, we can obtain the maximum temperature of the heating head of the Stirling engine. Therefore, the temperature of heating head can be higher than 1000 °C in our experiment on a sunny day. Moreover, the results also revealed that the temperature decrease of the heating head is less than the power decrease of solar irradiation because of the latent heat of copper and the small heat loss from the heating head.

  9. 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.

  10. Single Lens Dual-Aperture 3D Imaging System: Color Modeling

    Science.gov (United States)

    Bae, Sam Y.; Korniski, Ronald; Ream, Allen; Fritz, Eric; Shearn, Michael

    2012-01-01

    In an effort to miniaturize a 3D imaging system, we created two viewpoints in a single objective lens camera. This was accomplished by placing a pair of Complementary Multi-band Bandpass Filters (CMBFs) in the aperture area. Two key characteristics about the CMBFs are that the passbands are staggered so only one viewpoint is opened at a time when a light band matched to that passband is illuminated, and the passbands are positioned throughout the visible spectrum, so each viewpoint can render color by taking RGB spectral images. Each viewpoint takes a different spectral image from the other viewpoint hence yielding a different color image relative to the other. This color mismatch in the two viewpoints could lead to color rivalry, where the human vision system fails to resolve two different colors. The difference will be closer if the number of passbands in a CMBF increases. (However, the number of passbands is constrained by cost and fabrication technique.) In this paper, simulation predicting the color mismatch is reported.

  11. Resolution limit of probe-forming systems with magnetic quadrupole lens triplets and quadruplets

    CERN Document Server

    Ponomarev, A G; Miroshnichenko, V I; Storizhko, V E; Sulkio-Cleff, B

    2003-01-01

    Over the past decade, in MeV ion beam microanalysis efforts to achieve a spatial resolution better than 0.1 mu m with a beam current of approx 100 pA have been connected with microprobes of new generation where the probe is formed by means of separated magnetic quadrupole lens structures . However, as was pointed out in , no dramatic improvements in spatial resolution have been produced so far. For better understanding of the situation the authors carried out theoretical studies of multiparameter sets of probe-forming systems based on separated triplets and quadruplets of magnetic quadrupole lenses. Comparisons were made between the highest current values attained at different systems for a given beam spot size. The maximum parasitic sextupole and octupole field components were found whose contributions to spot broadening are tolerable. It is shown that the use of modern electrostatic accelerators and precision magnetic quadrupole lenses makes it possible to eliminate the effect of chromatic aberrations and s...

  12. Comparing the Zeiss Callisto Eye and the Alcon Verion Image Guided System Toric Lens Alignment Technologies.

    Science.gov (United States)

    Hura, Arjan S; Osher, Robert H

    2017-07-01

    To compare the alignment meridian generated by the Zeiss Callisto Eye (Carl Zeiss AG, Dublin, CA) and the Alcon Verion Image Guided System (Alcon Laboratories, Inc., Fort Worth, TX). In this retrospective comparative evaluation of technology, intraoperative images were captured at different steps in the same surgery, allowing the comparison of the guidance lines generated by the Verion system to the parallel guidance lines generated by the Callisto Eye system. Measurements of each hemi-meridian were quantified using Adobe Photoshop 2015 CC software (Adobe Systems, San Jose, CA). The numbers of degrees separating these alignment meridians were calculated, entered into a database, and analyzed. The authors found that of 98 captured images of 16 eyes, the two technologies were identical in 0 eyes (θ 1 = θ 2 = 0), similar by 3° in 52 (53%) captured images (θ 1 ≠ θ 2 ≠ 0), and different by at least 3° in 46 (47%) captured images (θ 1 ≠ θ 2 ≠ 0). The target meridians were superimposed, the target lines were minimally separated, and the target lines were dissimilar. It was noted that some intraoperative variation occurred from measurement to measurement. Within the small group of 16 cases of routine toric lens implantation in this study, the absolute average number of degrees of misalignment between the Verion and Callisto Eye systems was 3.355 for θ 1 and 3.838 for θ 2 . On average, the intraoperative variation termed "drift" was noted to be 3.963° for θ 1 , and 4.557° for θ 2 . The authors found that small deviations were frequent when comparing two sophisticated technologies. Although deviations greater than 3° occurred in less than 47% of captured images from 16 eyes, smaller but significant variations of less than 3° occurred in 53% of captured images from 16 eyes. It was rare to identify a large deviation. However, the authors identified "drift" in the same eye when measurements were taken at different times. The results indicate that the two

  13. Design and Optimization of Fresnel Lens for High Concentration Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Lei Jing

    2014-01-01

    Full Text Available A practical optimization design is proposed, in which the solar direct light spectrum and multijunction cell response range are taken into account in combination, particularly for the Fresnel concentrators with a high concentration and a small aspect ratio. In addition, the change of refractive index due to temperature variation in outdoor operation conditions is also considered in the design stage. The calculation results show that this novel Fresnel lens achieves an enhancement of energy efficiency of about 10% compared with conventional Fresnel lens for a given solar spectrum, solar cell response, and corrected sunshine hours of different ambient temperature intervals.

  14. Elevated central venous pressure is associated with impairment of microcirculatory blood flow in sepsis: a hypothesis generating post hoc analysis

    NARCIS (Netherlands)

    Vellinga, Namkje A. R.; Ince, C.; Boerma, E. C.

    2013-01-01

    Microcirculatory driving pressure is defined as the difference between post-arteriolar and venular pressure. In previous research, an absence of correlation between mean arterial blood pressure (MAP) and microcirculatory perfusion has been observed. However, the microcirculation may be considered as

  15. Involvement of nitric oxide in the wound bed microcirculatory change during negative pressure wound therapy.

    Science.gov (United States)

    Sano, Hitomi; Ichioka, Shigeru

    2015-08-01

    This study investigated the role of nitric oxide (NO) in the mechanism of blood flow increase in the wound bed during negative pressure wound therapy (NPWT). We developed an improved experimental model that allowed visualisation of the wound bed microcirculation under NPWT. Wounds were created on the mouse ear, taking care to preserve the subdermal vascular plexus, because the wound bed microcirculation was visualised using an intravital microscope system. We investigated whether application of a NO synthase inhibitor (N(G) -nitro-l-arginine methyl ester: L-NAME) might diminish the effect of the NPWT in increasing the wound blood flow. The experimental animals were divided into a negative pressure group (negative pressure of -125 mmHg applied to the wound for 5 minutes; n = 8), and a negative pressure plus L-NAME group (administration of L-NAME prior to application of the negative pressure; n = 8). In the negative pressure group, significant increase of blood flow was observed at 1 minute after the negative pressure application, which was sustained until 5 minutes. On the contrary, in the negative pressure plus L-NAME group, no significant changes were observed throughout the period of observation. These findings suggest that NO synthesis is involved in the wound bed microcirculatory change induced by NPWT. © 2013 The Authors. International Wound Journal © 2013 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  16. Unique rod lens/video system designed to observe flow conditions in emergency core coolant loops of pressurized water reactors

    International Nuclear Information System (INIS)

    Carter, G.W.

    1979-01-01

    Techniques and equipment are described which are used for video recordings of the single- and two-phase fluid flow tests conducted with the PKL Spool Piece Measurement System designed by Lawrence Livermore Laboratory and EG and G Inc. The instrumented spool piece provides valuable information on what would happen in pressurized water reactor emergency coolant loops should an accident or rupture result in loss of fluid. The complete closed-circuit television video system, including rod lens, light supply, and associated spool mounting fixtures, is discussed in detail. Photographic examples of test flows taken during actual spool piece system operation are shown

  17. Eye evolution: lens and cornea as an upgrade of animal visual system

    Czech Academy of Sciences Publication Activity Database

    Jonášová, Kristýna; Kozmik, Zbyněk

    2008-01-01

    Roč. 19, č. 2 (2008), s. 71-81 ISSN 1084-9521 R&D Projects: GA AV ČR IAA500520604; GA MŠk(CZ) 1M0520 Institutional research plan: CEZ:AV0Z50520514 Keywords : eye * lens * cornea Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.528, year: 2008

  18. The gravitational lens candidate HE 1104-1805 and the size of absorption systems

    NARCIS (Netherlands)

    Smette, A; Robertson, JG; Shaver, PA; Reimers, D; Wisotzki, L; Kohler, T; Kochanek, CS; Hewitt, JN

    1996-01-01

    We obtained 1.2 Angstrom resolution spectra over the range 3175 - 7575 Angstrom for the two components of the gravitational lens candidate HE 1104-1805 (z = 2.31, m(B) = 16.7 and 18.6, separation = 3.0 arcsec; cf. Wisotzki et al. 1993), with the aim of setting limits on the sizes of the clouds

  19. CNN-coupled Humanoid Panoramic Annular Lens (PAL)-Optical System for Military Applications (Feasibility Study)

    National Research Council Canada - National Science Library

    Greguss, Pal

    2002-01-01

    ...) and the CNN chip for a few military applications. A polar beam splitter will be placed immediately after the relay lens to obtain two image planes, one will be used by the existing 64X64 CNN-UM focal plane array processor chip...

  20. Calibration for medium resolution off-axis electron holography using a flexible dual-lens imaging system in a JEOL ARM 200F microscope

    International Nuclear Information System (INIS)

    Cantu-Valle, Jesus; Ruiz-Zepeda, Francisco; Mendoza-Santoyo, Fernando; Jose-Yacaman, Miguel; Ponce, Arturo

    2014-01-01

    In this work the calibration of a medium resolution off-axis electron holography using a dual-lens imaging system in a JEOL ARM 200F is shown. The objective dual-lens configuration allows adjusting the field of view from 35 nm to 2.5 μm. Subsequently, the parameters used in phase shift reconstruction were calibrated considering biprism voltage versus fringe spacing (σ) and versus fringe width (W). The reliability of the transmission electron microscope performance using these parameters was achieved using gold nanoparticles of known size and adjusting the excitation voltage of the lenses. - Highlights: • We presented the off-axis electron holography calibration in dual-lens mode of a JEOL ARM 200F. • We provide optimal conditions for a wide field of views varying the objective lens excitation. • The calibration was made using Au-nanoparticles controlling fringe width, spacing and contrast. • Application of electron holography to nanoparticles is also shown

  1. 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...

  2. Detection of angiospastic disorders in the microcirculatory bed using laser diagnostics technologies

    Directory of Open Access Journals (Sweden)

    Irina N. Makovik

    2018-01-01

    Thus, the evaluation of combined noninvasive optical diagnostic method use, the cold pressor test and proposed diagnostic criteria showed a positive result. This approach can be used to detect the presence of possible angiospastic disorders and related complications, as well as microcirculatory bed disorders against the background of other diseases.

  3. 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

  4. Using a complex adaptive system lens to understand family caregiving experiences navigating the stroke rehabilitation system.

    Science.gov (United States)

    Ghazzawi, Andrea; Kuziemsky, Craig; O'Sullivan, Tracey

    2016-10-01

    Family caregivers provide the stroke survivor with social support and continuity during the transition home from a rehabilitation facility. In this exploratory study we examined family caregivers' perceptions and experiences navigating the stroke rehabilitation system. The theories of continuity of care and complex adaptive systems were integrated to examine the transition from a stroke rehabilitation facility to the patient's home. This study provides an understanding of the interacting complexities at the macro and micro levels. A convenient sample of family caregivers (n = 14) who provide care for a stroke survivor were recruited 4-12 weeks following the patient's discharge from a stroke rehabilitation facility in Ontario, Canada. Interviews were conducted with family caregivers to examine their perceptions and experiences navigating the stroke rehabilitation system. Directed and inductive content analysis and the theory of Complex Adaptive Systems were used to interpret the perceptions of family caregivers. Health system policies and procedures at the macro-level determined the types and timing of information being provided to caregivers, and impacted continuity of care and access to supports and services at the micro-level. Supports and services in the community, such as outpatient physiotherapy services, were limited or did not meet the specific needs of the stroke survivors or family caregivers. Relationships with health providers, informational support, and continuity in case management all influence the family caregiving experience and ultimately the quality of care for the stroke survivor, during the transition home from a rehabilitation facility.

  5. Microcirculatory blood flow during cardiac arrest and cardiopulmonary resuscitation does not correlate with global hemodynamics: an experimental study.

    Science.gov (United States)

    Krupičková, Petra; Mlček, Mikuláš; Huptych, Michal; Mormanová, Zuzana; Bouček, Tomáš; Belza, Tomáš; Lacko, Stanislav; Černý, Miloš; Neužil, Petr; Kittnar, Otomar; Linhart, Aleš; Bělohlávek, Jan

    2016-06-08

    Current research highlights the role of microcirculatory disorders in post-cardiac arrest patients. Affected microcirculation shows not only dissociation from systemic hemodynamics but also strong connection to outcome of these patients. However, only few studies evaluated microcirculation directly during cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). The aim of our experimental study in a porcine model was to describe sublingual microcirculatory changes during CA and CPR using recent videomicroscopic technology and provide a comparison to parameters of global hemodynamics. Cardiac arrest was induced in 18 female pigs (50 ± 3 kg). After 3 min without treatment, 5 min of mechanical CPR followed. Continuous hemodynamic monitoring including systemic blood pressure and carotid blood flow was performed and blood lactate was measured at the end of baseline and CPR. Sublingual microcirculation was assessed by the Sidestream Dark Field (SDF) technology during baseline, CA and CPR. Following microcirculatory parameters were assessed off-line separately for capillaries (≤20 µm) and other vessels: total and perfused vessel density (TVD, PVD), proportion of perfused vessels (PPV), microvascular flow index (MFI) and heterogeneity index (HI). In comparison to baseline the CA small vessel microcirculation was only partially preserved: TVD 15.64 (13.59-18.48) significantly decreased to 12.51 (10.57-13.98) mm/mm(2), PVD 15.57 (13.56-17.80) to 5.53 (4.17-6.60) mm/mm(2), PPV 99.64 (98.05-100.00) to 38.97 (27.60-46.29) %, MFI 3.00 (3.00-3.08) to 1.29 (1.08-1.58) and HI increased from 0.08 (0.00-0.23) to 1.5 (0.71-2.00), p = 0.0003 for TVD and CPR in small vessels reached 59-85 % of the baseline values: TVD 13.33 (12.11-15.11) mm/mm(2), PVD 9.34 (7.34-11.52) mm/mm(2), PPV 72.34 (54.31-87.87) %, MFI 2.04 (1.58-2.42), HI 0.65 (0.41-1.07). The correlation between microcirculation and global hemodynamic parameters as well as to lactate was only weak to

  6. Kiloparsec Mass/Light Offsets in the Galaxy Pair-Lyα Emitter Lens System SDSS J1011+0143

    Science.gov (United States)

    Shu, Yiping; Bolton, Adam S.; Moustakas, Leonidas A.; Stern, Daniel; Dey, Arjun; Brownstein, Joel R.; Burles, Scott; Spinrad, Hyron

    2016-03-01

    We report the discovery of significant mass/light offsets in the strong gravitational lensing system SDSS J1011+0143. We use the high-resolution Hubble Space Telescope (HST) F555W- and F814W-band imaging and Sloan Digital Sky Survey (SDSS) spectroscopy of this system, which consists of a close galaxy pair with a projected separation of ≈ 4.2 {{kpc}} at zlens ˜ 0.331 lensing an Lyα emitter (LAE) at zsource = 2.701. Comparisons between the mass peaks inferred from lens models and light peaks from HST imaging data reveal significant spatial mass/light offsets as large as 1.72 ± 0.24 ± 0.34 kpc in both filter bands. Such large mass/light offsets, not seen in isolated field lens galaxies and relaxed galaxy groups, may be related to the interactions between the two lens galaxies. The detected mass/light offsets can potentially serve as an important test for the self-interacting dark matter model. However, other mechanisms such as dynamical friction on spatially differently distributed dark matter and stars could produce similar offsets. Detailed hydrodynamical simulations of galaxy-galaxy interactions with self-interacting dark matter could accurately quantify the effects of different mechanisms. The background LAE is found to contain three distinct star-forming knots with characteristic sizes from 116 to 438 pc. It highlights the power of strong gravitational lensing in probing the otherwise too faint and unresolved structures of distance objects below subkiloparsec or even 100 pc scales through its magnification effect. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. These observations are associated with program #10831.

  7. 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.

  8. Potential resistant morphotypes of Acanthamoeba castellanii expressed in multipurpose contact lens disinfection systems.

    Science.gov (United States)

    Ahearn, Donald G; Simmons, Robert B; Ward, Michael A; Stulting, R Doyle

    2012-11-01

    The free-living amoeba Acanthamoeba castellanii is a rare cause of contact lens-associated microbial keratitis. The cyst stage of this amoeba is noted for its resistance to disinfection by multipurpose contact lens solutions (MPS). This report examines and reviews the potential survival modes of A. castellanii in MPS. Trophozoites of A. castellanii (ATCC 30234) at densities from 10 to near 10 were incubated in 3 different MPS in a laminar flow hood for 24 hours at ambient temperatures. The dried films of MPS and phosphate-buffered saline (PBS) controls were examined before and after the addition of a peptone-yeast extract-glucose recovery broth (PYG) for the presence of amoeboid trophozoites and resistance stages over at least 7 days. The parallel exposure of trophozoites to MPS without evaporation or addition of PYG was similarly examined. Amoeboid trophozoites were not recovered in PYG nor were cyst-like structures observed in any MPS with near 10 densities. Progressively with 10 to 10 trophozoites, varied survival modes, particularly aggregates of trophozoites associated with cyst-like structures and occasional amoeboid forms and double-walled cysts with ostioles, became more evident. These morphotypes were most prominent after evaporation and typically first observed in the PYG. Trophozoites of A. castellanii near 10 and progressively to 10 densities are capable of expressing a variety of "short-term" survival modes in MPS, notably with the added stress of evaporation. Expression of these alternate survival modes in MPS may relate, in part, to contamination of contact lens cases and difficulties in developing standardized MPS efficacy tests.

  9. Identification and quantification of human microcirculatory leukocytes using handheld video microscopes at the bedside.

    Science.gov (United States)

    Uz, Zühre; van Gulik, Thomas M; Aydemirli, Mehtap Derya; Guerci, Philippe; Ince, Yasin; Cuppen, Diede V; Ergin, Bulent; Aksu, Ugur; de Mol, Bas A; Ince, Can

    2018-03-08

    Leukocyte recruitment and adhesion to the endothelium are hallmarks of systemic inflammation that manifest in a wide range of diseases. At present, no method is available to directly measure leukocyte kinetics at the bedside. In this study, we validate a new method to identify and quantify microcirculatory leukocytes observed by handheld vital microscopy (HVM) using space-time diagram (STD) analysis. Video clips (N=59) containing one capillary-post capillary venule (C-PCV) unit where leukocytes could be observed emanating from a capillary into a venule in cardiac surgery patients (N=20) were included. STD analysis and manual counting were used to quantify the number of leukocytes (total, rolling and non-rolling). Pearson's correlation and Bland-Altman analysis were used to determine agreement between the STDs and manual counting. For reproducibility, intra- and inter-observer coefficients of variation (CVs) were assessed. Leukocyte (rolling and non-rolling) and red blood cell velocities were assessed. The STDs and manual counting procedures for the quantification of rolling leukocytes showed good agreement (r=0.8197, P<0.0001), with a Bland-Altman analysis mean difference of -0.0 (-6.56; 6.56). The overall intra-observer CV for the STD method was 1.5%. The overall inter-observer CVs for the STD and the manual method were 5.6% and 9.4%, respectively. The non-rolling velocity was significantly higher than the rolling velocity (812{plus minus}519 µm/s vs 201{plus minus}149 µm/s, P=0.001). The STD results agreed with the manual counting procedure results, had a better reproducibility and could assess the leukocyte velocity. STD analysis using bedside HVM imaging presented a new methodology for quantifying leukocyte kinetics and functions in the microcirculation.

  10. The small-animal radiation research platform (SARRP): dosimetry of a focused lens system

    International Nuclear Information System (INIS)

    Deng Hua; Kennedy, Christopher W; Armour, Elwood; Tryggestad, Erik; Ford, Eric; McNutt, Todd; Jiang Licai; Wong, John

    2007-01-01

    A small animal radiation platform equipped with on-board cone-beam CT and conformal irradiation capabilities is being constructed for translational research. To achieve highly localized dose delivery, an x-ray lens is used to focus the broad beam from a 225 kVp x-ray tube down to a beam with a full width half maximum (FWHM) of approximately 1.5 mm in the energy range 40-80 keV. Here, we report on the dosimetric characteristics of the focused beam from the x-ray lens subsystem for high-resolution dose delivery. Using the metric of the average dose within a 1.5 mm diameter area, the dose rates at a source-to-surface distance (SSD) of 34 cm are 259 and 172 cGy min -1 at 6 mm and 2 cm depths, respectively, with an estimated uncertainty of ±5%. The per cent depth dose is approximately 56% at 2 cm depth for a beam at 34 cm SSD

  11. The small-animal radiation research platform (SARRP): dosimetry of a focused lens system

    Energy Technology Data Exchange (ETDEWEB)

    Deng Hua [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medicine, Baltimore, MD (United States); Kennedy, Christopher W [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medicine, Baltimore, MD (United States); Armour, Elwood [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medicine, Baltimore, MD (United States); Tryggestad, Erik [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medicine, Baltimore, MD (United States); Ford, Eric [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medicine, Baltimore, MD (United States); McNutt, Todd [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medicine, Baltimore, MD (United States); Jiang Licai [OSMIC Inc., 1900 Taylor Rd., Auburn Hills, MI (United States); Wong, John [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medicine, Baltimore, MD (United States)

    2007-05-21

    A small animal radiation platform equipped with on-board cone-beam CT and conformal irradiation capabilities is being constructed for translational research. To achieve highly localized dose delivery, an x-ray lens is used to focus the broad beam from a 225 kVp x-ray tube down to a beam with a full width half maximum (FWHM) of approximately 1.5 mm in the energy range 40-80 keV. Here, we report on the dosimetric characteristics of the focused beam from the x-ray lens subsystem for high-resolution dose delivery. Using the metric of the average dose within a 1.5 mm diameter area, the dose rates at a source-to-surface distance (SSD) of 34 cm are 259 and 172 cGy min{sup -1} at 6 mm and 2 cm depths, respectively, with an estimated uncertainty of {+-}5%. The per cent depth dose is approximately 56% at 2 cm depth for a beam at 34 cm SSD.

  12. Off-axis electron holography with a dual-lens imaging system and its usefulness in 2-D potential mapping of semiconductor devices.

    Science.gov (United States)

    Wang, Y Y; Kawasaki, M; Bruley, J; Gribelyuk, M; Domenicucci, A; Gaudiello, J

    2004-11-01

    A variable magnification electron holography, applicable for two-dimensional (2-D) potential mapping of semiconductor devices, employing a dual-lens imaging system is described. Imaging operation consists of a virtual image formed by the objective lens (OL) and a real image formed in a fixed imaging plane by the objective minilens. Wide variations in field of view (100-900 nm) and fringe spacing (0.7-6 nm) were obtained using a fixed biprism voltage by varying the total magnification of the dual OL system. The dual-lens system allows fringe width and spacing relative to the object to be varied roughly independently from the fringe contrast, resulting in enhanced resolution and sensitivity. The achievable fringe width and spacing cover the targets needed for devices in the semiconductor technology road map from the 350 to 45 nm node. Two-D potential maps for CMOS devices with 220 and 70 nm gate lengths were obtained.

  13. Impact of eight weeks of repeated ischaemic preconditioning on brachial artery and cutaneous microcirculatory function in healthy males.

    NARCIS (Netherlands)

    Jones, H.; Nyakayiru, J.; Bailey, T.G.; Green, D.J.; Cable, N.T.; Sprung, V.S.; Hopkins, N.D.; Thijssen, D.H.J.

    2015-01-01

    BACKGROUND: Ischaemic preconditioning has well-established cardiac and vascular protective effects. Short interventions (one week) of daily ischaemic preconditioning episodes improve conduit and microcirculatory function. This study examined whether a longer (eight weeks) and less frequent (three

  14. Objective-lens-free Fiber-based Position Detection with Nanometer Resolution in a Fiber Optical Trapping System.

    Science.gov (United States)

    Ti, Chaoyang; Ho-Thanh, Minh-Tri; Wen, Qi; Liu, Yuxiang

    2017-10-13

    Position detection with high accuracy is crucial for force calibration of optical trapping systems. Most existing position detection methods require high-numerical-aperture objective lenses, which are bulky, expensive, and difficult to miniaturize. Here, we report an affordable objective-lens-free, fiber-based position detection scheme with 2 nm spatial resolution and 150 MHz bandwidth. This fiber based detection mechanism enables simultaneous trapping and force measurements in a compact fiber optical tweezers system. In addition, we achieved more reliable signal acquisition with less distortion compared with objective based position detection methods, thanks to the light guiding in optical fibers and small distance between the fiber tips and trapped particle. As a demonstration of the fiber based detection, we used the fiber optical tweezers to apply a force on a cell membrane and simultaneously measure the cellular response.

  15. 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

  16. Coffee polyphenols extracted from green coffee beans improve skin properties and microcirculatory function.

    Science.gov (United States)

    Fukagawa, Satoko; Haramizu, Satoshi; Sasaoka, Shun; Yasuda, Yuka; Tsujimura, Hisashi; Murase, Takatoshi

    2017-09-01

    Coffee polyphenols (CPPs), including chlorogenic acid, exert various physiological activities. The purpose of this study was to investigate the effects of CPPs on skin properties and microcirculatory function in humans. In this double-blind, placebo-controlled study, 49 female subjects with mildly xerotic skin received either a test beverage containing CPPs (270 mg/100 mL/day) or a placebo beverage for 8 weeks. The ingestion of CPPs significantly lowered the clinical scores for skin dryness, decreased transepidermal water loss, skin surface pH, and increased stratum corneum hydration and the responsiveness of skin blood flow during local warming. Moreover, the amounts of free fatty acids and lactic acid in the stratum corneum significantly increased after the ingestion of CPPs. These results suggest that an 8-week intake of CPPs improve skin permeability barrier function and hydration, with a concomitant improvement in microcirculatory function, leading to efficacy in the alleviation of mildly xerotic skin.

  17. Capillaries in the Brain Microcirculatory Bed in the Acute Period of Experimental Brain Injury

    Directory of Open Access Journals (Sweden)

    V. Ye. Klimenko

    2010-01-01

    Full Text Available Objective: to provide a morphochemical evaluation of the capillaries in the brain microcirculatory bed of experimental animals in the acute period of brain injury (BI. Materials and methods. An experiment was carried out on 40 sexually mature Wister rats. Gradual BI was inflicted by a falling load blow on the right parietotemporal region, as described by T. F. Sokolova (1986. Brain magnetic resonance imaging was made in the animals an hour after injury infliction to define the extent of the damage and its site. Morphological studies of the brain were conducted 24 and 72 hours and 7 days after the injury. The capillaries were identified by the injection technique (Indian ink imbedding. The NO-producing function of endotheliocytes was evaluated using the NADPH-diaphorase histochemical technique. To study microcirculatory changes, the similar brain portions ipsilateral to the site of injury and in the intact hemisphere were compared in each animal. The changes in the diameter of capillaries, the volume density of the microcirculatory bed, the exchange surface area and activity of NADPH diaphorase in the capillary wall were analyzed. The findings were processed by the variation statistical method, by determining the arithmetic mean, the standard error of the arithmetic mean, and the test of significance. The findings give an insight into the mechanisms responsible for secondary ischemic lesions in the early period of brain injury. The NO-dependent capillary blood flow reduction leading to hypoxia may be one of the most important causes of secondary cerebral lesion. All changes in the dynamics of microvessels (their lumen and area are in line with the activity of the enzyme. Conclusion. In severe BI, changes in the brain microcirculatory bed, its capillary link in particular, are manifested not only with in a traumatic injury focus, but also involve the brain as a whole. Key words: brain, brain njury, capillaries, nitric oxide (NO.

  18. Raster-scan optoacoustic angiography reveals 3D microcirculatory changes during cuffed occlusion

    Science.gov (United States)

    Subochev, Pavel; Orlova, Anna; Smolina, Ekaterina; Kirillov, Aleksey; Shakhova, Natalia; Turchin, Ilya

    2018-04-01

    Acoustic resolution photoacoustic microscopy at the optical wavelength of 532 nm was used to investigate the functional reaction of blood vessels of healthy human skin during cuffed venous occlusion. The high bandwidth of the polyvinilidene difluoride detector provided the opportunity for raster-scan optoacoustic angiography of both the superficial and deep plexuses at the high resolution of 35/50 microns (axial/lateral). A reversible increase of blood supply in the microcirculatory bed during occlusion was revealed.

  19. A Constructive Reframing of Student Roles and Systems Learning in Medical Education Using a Communities of Practice Lens.

    Science.gov (United States)

    Gonzalo, Jed D; Thompson, Britta M; Haidet, Paul; Mann, Karen; Wolpaw, Daniel R

    2017-12-01

    Health systems are in the midst of a transformation that is being driven by a variety of forces. This has important implications for medical educators because clinical practice environments play a key role in learning and professional development, and evolving health systems are beginning to demand that providers have "systems-ready" knowledge, attitudes, and skills. Such implications provide a clear mandate for medical schools to modify their goals and prepare physicians to practice flexibly within teams and effectively contribute to the improvement of health care delivery. In this context, the concepts of value-added medical education, authentic student roles, and health systems science are emerging as increasingly important. In this Article, the authors use a lens informed by communities of practice theory to explore these three concepts, examining the implications that the communities of practice theory has in the constructive reframing of educational practices-particularly common student roles and experiences-and charting future directions for medical education that better align with the needs of the health care system. The authors apply several key features of the communities of practice theory to current experiential roles for students, then propose a new approach to students' clinical experiences-value-added clinical systems learning roles-that provides students with opportunities to make meaningful contributions to patient care while learning health systems science at the patient and population level. Finally, the authors discuss implications for professional role formation and anticipated challenges to the design and implementation of value-added clinical systems learning roles.

  20. Calibration for medium resolution off-axis electron holography using a flexible dual-lens imaging system in a JEOL ARM 200F microscope.

    Science.gov (United States)

    Cantu-Valle, Jesus; Ruiz-Zepeda, Francisco; Mendoza-Santoyo, Fernando; Jose-Yacaman, Miguel; Ponce, Arturo

    2014-12-01

    In this work the calibration of a medium resolution off-axis electron holography using a dual-lens imaging system in a JEOL ARM 200F is shown. The objective dual-lens configuration allows adjusting the field of view from 35nm to 2.5μm. Subsequently, the parameters used in phase shift reconstruction were calibrated considering biprism voltage versus fringe spacing (σ) and versus fringe width (W). The reliability of the transmission electron microscope performance using these parameters was achieved using gold nanoparticles of known size and adjusting the excitation voltage of the lenses. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Propagation of flat-topped multi-Gaussian beams through a double-lens system with apertures.

    Science.gov (United States)

    Gao, Yanqi; Zhu, Baoqiang; Liu, Daizhong; Lin, Zunqi

    2009-07-20

    A general model for different apertures and flat-topped laser beams based on the multi-Gaussian function is developed. The general analytical expression for the propagation of a flat-topped beam through a general double-lens system with apertures is derived using the above model. Then, the propagation characteristics of the flat-topped beam through a spatial filter are investigated by using a simplified analytical expression. Based on the Fluence beam contrast and the Fill factor, the influences of a pinhole size on the propagation of the flat-topped multi-Gaussian beam (FMGB) through the spatial filter are illustrated. An analytical expression for the propagation of the FMGB through the spatial filter with a misaligned pinhole is presented, and the influences of the pinhole offset are evaluated.

  2. The SADI Personal Health Lens: A Web Browser-Based System for Identifying Personally Relevant Drug Interactions.

    Science.gov (United States)

    Vandervalk, Ben; McCarthy, E Luke; Cruz-Toledo, José; Klein, Artjom; Baker, Christopher J O; Dumontier, Michel; Wilkinson, Mark D

    2013-04-05

    The Web provides widespread access to vast quantities of health-related information that can improve quality-of-life through better understanding of personal symptoms, medical conditions, and available treatments. Unfortunately, identifying a credible and personally relevant subset of information can be a time-consuming and challenging task for users without a medical background. The objective of the Personal Health Lens system is to aid users when reading health-related webpages by providing warnings about personally relevant drug interactions. More broadly, we wish to present a prototype for a novel, generalizable approach to facilitating interactions between a patient, their practitioner(s), and the Web. We utilized a distributed, Semantic Web-based architecture for recognizing personally dangerous drugs consisting of: (1) a private, local triple store of personal health information, (2) Semantic Web services, following the Semantic Automated Discovery and Integration (SADI) design pattern, for text mining and identifying substance interactions, (3) a bookmarklet to trigger analysis of a webpage and annotate it with personalized warnings, and (4) a semantic query that acts as an abstract template of the analytical workflow to be enacted by the system. A prototype implementation of the system is provided in the form of a Java standalone executable JAR file. The JAR file bundles all components of the system: the personal health database, locally-running versions of the SADI services, and a javascript bookmarklet that triggers analysis of a webpage. In addition, the demonstration includes a hypothetical personal health profile, allowing the system to be used immediately without configuration. Usage instructions are provided. The main strength of the Personal Health Lens system is its ability to organize medical information and to present it to the user in a personalized and contextually relevant manner. While this prototype was limited to a single knowledge domain

  3. 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.

  4. 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

  5. Exploring the effects of task shifting for HIV through a systems thinking lens: the case of Burkina Faso.

    Science.gov (United States)

    Yaya Bocoum, Fadima; Kouanda, Seni; Kouyaté, Bocar; Hounton, Sennen; Adam, Taghreed

    2013-10-22

    While the impact of task shifting on quality of care and clinical outcomes has been demonstrated in several studies, evidence on its impact on the health system as a whole is limited. This study has two main objectives. The first is to conceptualize the wider range of effects of task shifting through a systems thinking lens. The second is to explore these effects using task shifting for HIV in Burkina Faso as a case study. We used a case study approach, using qualitative research methods. Data sources included document reviews, reviews of available data and records, as well as interviews with key informants and health workers. In addition to the traditional measures of impact of task shifting on health outcomes, our study identified 20 possible effects of the strategy on the system as a whole. Moreover, our analysis highlighted the importance of differentiating between two types of health systems effects. The first are effects inherent to the task shifting strategy itself, such as job satisfaction or better access to health services. The second are effects due to health system barriers, for example the unavailability of medicines and supplies, generating a series of effects on the various components of the health system, e.g., staff frustration.Among the health systems effects that we found are positive, mostly unintended, effects and synergies such as increased health workers' sense of responsibility and worthiness, increased satisfaction due to using the newly acquired skills in other non-HIV tasks, as well as improved patient-provider relationships. Among the negative unintended effects are staff frustration due to lack of medicines and supplies or lack of the necessary infrastructure to be able to perform the new tasks. Our analysis highlights the importance of adopting a systems thinking approach in designing, implementing and evaluating health policies to mitigate some of the design issues or system bottle-necks that may impede their successful implementation

  6. Signal-to-noise ratio and dose to the lens of the eye for computed tomography examination of the brain using an automatic tube current modulation system.

    Science.gov (United States)

    Sookpeng, Supawitoo; Butdee, Chitsanupong

    2017-06-01

    The study aimed to evaluate the image quality in terms of signal-to-noise ratio (SNR) and dose to the lens of the eye and the other nearby organs from the CT brain scan using an automatic tube current modulation (ATCM) system with or without CT gantry tilt is needed. An anthropomorphic phantom was scanned with different settings including use of different ATCM, fixed tube current time product (mAs) settings and degree angles of gantry tilt. Gafchromic film XR-QA2 was used to measure absorbed dose of the organs. Relative doses and SNR for the various scan settings were compared with the reference setting of the fixed 330 mAs. Average absorbed dose for the lens of the eyes varied from 8.7 to 21.7 mGy. The use of the ATCM system with the gantry tilt resulted in up to 60% decrease in the dose to the lens of the eye. SNR significantly decreased while tilting the gantry using the fixed mAs techniques, compared to that of the reference setting. However, there were no statistical significant differences for SNRs between the reference setting and all ATCM settings. Compared to the reference setting of the fixed effective mAs, using the ATCM system and appropriate tilting, the gantry resulted in a substantial decrease in the dose to the lens of the eye while preserving signal-to-noise ratio. CT brain examination should be carefully controlled to optimize dose for lens of the eye and image quality of the examination.

  7. [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.

  8. The Impact of Lens Opacity on SD-OCT Retinal Nerve Fiber Layer and Bruch's Membrane Opening Measurements Using the Anatomical Positioning System (APS).

    Science.gov (United States)

    Mauschitz, Matthias M; Roth, Felix; Holz, Frank G; Breteler, Monique M B; Finger, Robert P

    2017-05-01

    To evaluate the impact of lens opacity on retinal nerve fiber layer thickness (RNFLT) and Bruch's membrane opening (BMO) measurements. Fifty-nine randomly selected patients without any other relevant ocular pathology undergoing elective routine cataract surgery in two specialized eye clinics were enrolled. RNFLT, BMO area, and BMO minimum rim width (BMO-MRW) were assessed with the Heidelberg Engineering Spectralis OCT using the anatomical positioning system (APS) prior to and 1 day after cataract surgery using a ring scan at different eccentricities of the disc (3.5, 4.1 and 4.7 mm). Lens opacity was quantified using densitometry based on Scheimpflug images (Oculus Pentacam AXL). RNFLT, BMO area, and BMO-MRW were virtually identical before and following removal of the cataractous lens. This held when assessed overall, within the six sectors for the 3.5-mm scan, or at any other eccentricity. Baseline RNFLT was not associated with lens opacity. Using the APS, RNFLT remained unchanged following cataract surgery, contrary to results reported by previous studies. Our results imply that the APS may have contributed to more precise spectral-domain optical coherence measurements, minimizing the influence of cataract on RNFLT and BMO assessments in our cohort.

  9. Eye lens dose correlations with personal dose equivalent and patient exposure in paediatric interventional cardiology performed with a fluoroscopic biplane system.

    Science.gov (United States)

    Alejo, L; Koren, C; Corredoira, E; Sánchez, F; Bayón, J; Serrada, A; Guibelalde, E

    2017-04-01

    To analyse the correlations between the eye lens dose estimates performed with dosimeters placed next to the eyes of paediatric interventional cardiologists working with a biplane system, the personal dose equivalent measured on the thorax and the patient dose. The eye lens dose was estimated in terms of H p (0.07) on a monthly basis, placing optically stimulated luminescence dosimeters (OSLDs) on goggles. The H p (0.07) personal dose equivalent was measured over aprons with whole-body OSLDs. Data on patient dose as recorded by the kerma-area product (P KA ) were collected using an automatic dose management system. The 2 paediatric cardiologists working in the facility were involved in the study, and 222 interventions in a 1-year period were evaluated. The ceiling-suspended screen was often disregarded during interventions. The annual eye lens doses estimated on goggles were 4.13±0.93 and 4.98±1.28mSv. Over the aprons, the doses obtained were 10.83±0.99 and 11.97±1.44mSv. The correlation between the goggles and the apron dose was R 2 =0.89, with a ratio of 0.38. The correlation with the patient dose was R 2 =0.40, with a ratio of 1.79μSvGy -1 cm -2 . The dose per procedure obtained over the aprons was 102±16μSv, and on goggles 40±9μSv. The eye lens dose normalized to P KA was 2.21±0.58μSvGy -1 cm -2 . Measurements of personal dose equivalent over the paediatric cardiologist's apron are useful to estimate eye lens dose levels if no radiation protection devices are typically used. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  10. 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...

  11. Illumination uniformity issue explored via two-stage solar concentrator system based on Fresnel lens and compound flat concentrator

    International Nuclear Information System (INIS)

    Yeh, Naichia

    2016-01-01

    This paper illustrates details about the solar radiation distribution on the target of a two-stage solar concentrator that combines the Fresnel lens (FL) and the compound flat concentrator (CFC). The paper starts with a review of some FL development milestones such as the two-stage systems and the comparisons of flat vs. curved lenses in addition to the most noteworthy FL-based solar energy application, concentration photovoltaic (CPV). Through the review of the FL based CPV and two-stage concentrators, this study leads to the development of an algorithm to explore the spectrum distribution insight on the receiver of a two-stage (FL plus CFC) solar concentration system. It established the potential for using a correctly positioned 2nd stage reflector of right dimension to selectively redirect the desired spectrum on the target area so as to enhance the concentration flux intensity and uniformity at the same time. The study also helped to chart out the approximate locations of certain spectrum segments on the FL's target area, which is useful for exploring the spectrum control mechanism via the Fresnel lenses. - Highlights: • Map out the approximate locations of spectrum segments on FL's focal area. • Use the 2nd stage reflector to selectively reflect the desired spectrum on target. • Explore the spectrum distribution insight on FL solar concentrators' target area.

  12. VizieR Online Data Catalog: LCs & spectra of SDSS J1515+1511 lens system (Shalyapin+, 2017)

    Science.gov (United States)

    Shalyapin, V. N.; Goicoechea, L. J.

    2017-09-01

    We conducted a photometric monitoring campaign of SDSS J1515+1511 from early February of 2014 to mid September of 2016, i.e., for 2.6yr with an average sampling rate of about two nights every week. All optical observations were performed with the 2.0m fully robotic Liverpool Telescope (LT) at the Roque de los Muchachos Observatory, Canary Islands (Spain). Deep long-slit spectra of SDSS J1515+1511 were obtained using the R500B and R500R grisms in the OSIRIS spectrograph on the 10.4m Gran Telescopio Canarias (GTC). We took a single 1800s exposure with the blue grism (R500B) on 2015 April 15. We also observed the lens system with the red grism (R500R) on 2015 April 16. Hence, the new data cover a wavelength range of 3570-9250Å with a resolving power of ~300-400. We observed SDSS J1515+1511 with the SPRAT long-slit spectrograph on 2015 August 16 (red grating) and 2015 August 18 (blue). We have re-observed the system on 2016 March 17 (blue). (5 data files).

  13. Microcirculatory assessment of patients under VA-ECMO

    NARCIS (Netherlands)

    A. Kara (Atila); S. Akin (Sakir); D. dos Reis Miranda (Dinis); A. Struijs (Ard); K. Caliskan (Kadir); R.J. van Thiel (Robert); E.A. Dubois; de Wilde, W. (Wouter); F. Zijlstra (Felix); D.A.M.P.J. Gommers (Diederik); C. Ince (Can)

    2016-01-01

    textabstractBackground: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an effective technique for providing emergency mechanical circulatory support for patients with cardiogenic shock. VA-ECMO enables a rapid restoration of global systemic organ perfusion, but it has not been found

  14. Microcirculatory assessment of patients under VA-ECMO

    NARCIS (Netherlands)

    Kara, Atila; Akin, Sakir; Dos Reis Miranda, Dinis; Struijs, Ard; Caliskan, Kadir; van Thiel, Robert J.; Dubois, Eric A.; de Wilde, Wouter; Zijlstra, Felix; Gommers, Diederik; Ince, Can

    2016-01-01

    Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an effective technique for providing emergency mechanical circulatory support for patients with cardiogenic shock. VA-ECMO enables a rapid restoration of global systemic organ perfusion, but it has not been found to always show a

  15. Modulation transfer function estimation of optical lens system by adaptive neuro-fuzzy methodology

    Science.gov (United States)

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

    2014-07-01

    The quantitative assessment of image quality is an important consideration in any type of imaging system. The modulation transfer function (MTF) is a graphical description of the sharpness and contrast of an imaging system or of its individual components. The MTF is also known and spatial frequency response. The MTF curve has different meanings according to the corresponding frequency. The MTF of an optical system specifies the contrast transmitted by the system as a function of image size, and is determined by the inherent optical properties of the system. In this study, the adaptive neuro-fuzzy (ANFIS) estimator is designed and adapted to estimate MTF value of the actual optical system. Neural network in ANFIS adjusts parameters of membership function in the fuzzy logic of the fuzzy inference system. The back propagation learning algorithm is used for training this network. This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

  16. Optical tweezers and surface plasmon resonance combination system based on the high numerical aperture lens

    Science.gov (United States)

    Shan, Xuchen; Zhang, Bei; Lan, Guoqiang; Wang, Yiqiao; Liu, Shugang

    2015-11-01

    Biology and medicine sample measurement takes an important role in the microscopic optical technology. Optical tweezer has the advantage of accurate capture and non-pollution of the sample. The SPR(surface plasmon resonance) sensor has so many advantages include high sensitivity, fast measurement, less consumption of sample and label-free detection of biological sample that the SPR sensing technique has been used for surface topography, analysis of biochemical and immune, drug screening and environmental monitoring. If they combine, they will play an important role in the biological, chemical and other subjects. The system we propose use the multi-axis cage system, by using the methods of reflection and transmiss ion to improve the space utilization. The SPR system and optical tweezer were builtup and combined in one system. The cage of multi-axis system gives full play to its accuracy, simplicity and flexibility. The size of the system is 20 * 15 * 40 cm3 and thus the sample can be replaced to switch between the optical tweezers system and the SPR system in the small space. It means that we get the refractive index of the sample and control the particle in the same system. In order to control the revolving stage, get the picture and achieve the data stored automatically, we write a LabVIEW procedure. Then according to the data from the back focal plane calculate the refractive index of the sample. By changing the slide we can trap the particle as optical tweezer, which makes us measurement and trap the sample at the same time.

  17. A reflective lens: applying critical systems thinking and visual methods to ecohealth research.

    Science.gov (United States)

    Cleland, Deborah; Wyborn, Carina

    2010-12-01

    Critical systems methodology has been advocated as an effective and ethical way to engage with the uncertainty and conflicting values common to ecohealth problems. We use two contrasting case studies, coral reef management in the Philippines and national park management in Australia, to illustrate the value of critical systems approaches in exploring how people respond to environmental threats to their physical and spiritual well-being. In both cases, we used visual methods--participatory modeling and rich picturing, respectively. The critical systems methodology, with its emphasis on reflection, guided an appraisal of the research process. A discussion of these two case studies suggests that visual methods can be usefully applied within a critical systems framework to offer new insights into ecohealth issues across a diverse range of socio-political contexts. With this article, we hope to open up a conversation with other practitioners to expand the use of visual methods in integrated research.

  18. 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 ...

  19. N-Acetylcysteine's Role in Sepsis and Potential Benefit in Patients With Microcirculatory Derangements.

    Science.gov (United States)

    Chertoff, Jason

    2018-02-01

    To review the data surrounding the utility of N-acetylcysteine (NAC) in sepsis and identify areas needed for additional research. A review of articles describing the mechanisms of action and clinical use of NAC in sepsis. Despite many advances in critical care medicine, still as many as 50% of patients with septic shock die. Treatments thus far have focused on resuscitation and restoration of macrocirculatory targets in the early phases of sepsis, with less focus on microcirculatory dysfunction. N-acetylcysteine, due to its anti-inflammatory and antioxidative properties, has been readily investigated in sepsis and has yielded largely incongruous and disappointing results. In addition to its known anti-inflammatory and antioxidative roles, one underappreciated property of NAC is its ability to vasodilate the microcirculation and improve locoregional blood flow. Some investigators have sought to capitalize on this mechanism with promising results, as evidenced by microcirculatory vasodilation, improvements in regional blood flow and oxygen delivery, and reductions in lactic acidosis, organ failure, and mortality. In addition to its antioxidant and anti-inflammatory properties, N-acetylcysteine possesses vasodilatory properties that could benefit the microcirculation in sepsis. It is imperative that we investigate these properties to uncover NAC's full potential for benefit in sepsis.

  20. Climate impacts, climate policies, and the role of adaptation through the lens of water systems

    Science.gov (United States)

    Hejazi, M. I.

    2016-12-01

    Recognizing the critical role of water in human-Earth system interactions, most integrated assessment models are moving to incorporate water within their modeling frameworks and climate change impacts more broadly. However, none of the IA models used in generating the four representative concentration pathways (RCPs) incorporated the potential feedbacks of water limitations on other modeled systems, meaning that these assessments did not consider the joint interactions between hydrologic and human systems simultaneously adapting to and mitigating climate change. Yet, hydrologic systems could impose severe limitations on both energy and land decisions. Also, previous efforts have been limited to taking information from IA and Earth system models and passing that information to global water management and hydrologic models with the implicit assumption that all unmet water demands are taken from non-renewable water resources, generally fossil groundwater. However, extracting and depleting water resources (e.g., aquifers) could have drastic impacts on both energy and land use systems and the ability to mitigate climate change. In this study, we use the Global Change Assessment Model (GCAM), where interactions between population, economic growth, energy, land and water resources interact simultaneously in a dynamically evolving system, to investigate: 1) how water scarcity affects energy and land use decisions as well as mitigation policies, 2) the effects of climate change impacts on the food-energy-water nexus, 3) how these impacts evolve in the context of the shared socioeconomic pathways (SSPs) with specific details on water technologies, 4) the effects of different adaptation measures and their associate investment costs, and 5) the relative contributions of climate and human systems on water scarcity. We find that previous estimates of global water withdrawal projections are overestimated, as our simulations show that it is more economical in some basins to alter

  1. A classification system of intraocular lens dislocation sites under operating microscopy, and the surgical techniques and outcomes of exchange surgery.

    Science.gov (United States)

    Hayashi, Ken; Ogawa, Soichiro; Manabe, Shin-Ichi; Hirata, Akira; Yoshimura, Koichi

    2016-03-01

    The aim of this study was to examine the recent status of intraocular lens (IOL) dislocation according to a classification system based on vertical dislocation position, as well as the surgical techniques and outcomes of IOL exchange surgery. The medical records of 230 eyes from 214 consecutive patients who experienced IOL dislocation and underwent exchange surgery between 2006 and 2014 were reviewed. Vertical dislocation sites observed preoperatively under operating microscopy were examined, along with the surgical techniques and outcomes of IOL exchange. Dislocation sites included (1) the anterior chamber (12.2 %), (2) pseudophakodonesis (19.1 %), (3) the anterior vitreous cavity (47.4 %), (4) trap door-like dislocation (dangling in the peripheral vitreous cavity; 16.1 %), and (5) the retinal surface (5.2 %). The IOL retained in the anterior segment was moved onto the iris by pulling it up through the limbal side ports with an anterior vitrectomy (67.8 %), or by pushing it up from the pars plana with an anterior vitrectomy (26.5 %), while the IOL dropped on the retina was lifting it up from the retina after pars plana vitrectomy (5.7 %). Mean uncorrected and distance-corrected visual acuity significantly improved postoperatively (p system, approximately 95 % of dislocated IOLs were retained in the anterior segment, and these IOLs were exchanged using an anterior approach through limbal incisions with an anterior vitrectomy. Visual acuity improved significantly, and serious complications were uncommon, probably because the IOL exchange techniques were standardized and simplified without pars plana vitrectomy.

  2. 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.

  3. RETRACTED: Adaptive neuro-fuzzy prediction of modulation transfer function of optical lens system

    Science.gov (United States)

    Petković, Dalibor; Shamshirband, Shahaboddin; Anuar, Nor Badrul; Md Nasir, Mohd Hairul Nizam; Pavlović, Nenad T.; Akib, Shatirah

    2014-07-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor. Sections ;1. Introduction; and ;2. Modulation transfer function;, as well as Figures 1-3, plagiarize the article published by N. Gül and M. Efe in Turk J Elec Eng & Comp Sci 18 (2010) 71 (http://journals.tubitak.gov.tr/elektrik/issues/elk-10-18-1/elk-18-1-6-0811-9.pdf). Sections ;4. Adaptive neuro-fuzzy inference system; and ;6. Conclusion; duplicate parts of the articles previously published by the corresponding author et al in ;Expert Systems with Applications; 39 (2012) 13295-13304, http://dx.doi.org/10.1016/j.eswa.2012.05.072 and ;Expert Systems with Applications; 40 (2013) 281-286, http://dx.doi.org/10.1016/j.eswa.2012.07.076. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper is not under consideration for publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents an abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

  4. Using the Lens of Social Capital to Understand Diversity in the Earth System Sciences Workforce

    Science.gov (United States)

    Callahan, Caitlin N.; Libarkin, Julie C.; McCallum, Carmen M.; Atchison, Christopher L.

    2015-01-01

    In this commentary, we argue that social capital theory, the idea that membership in a group creates opportunities to acquire valuable information and resources from other group members, is a useful framework in which to consider ways to increase diversity in the Earth System Sciences (ESS) and in the science, technology, engineering, and…

  5. Time Evolution of Sublingual Microcirculatory Changes in Recreational Marathon Runners.

    Science.gov (United States)

    Pranskunas, Andrius; Arstikyte, Justina; Pranskuniene, Zivile; Bernatoniene, Jurga; Kiudulaite, Inga; Vaitkaitiene, Egle; Vaitkaitis, Dinas; Brazaitis, Marius

    2017-01-01

    We aimed to evaluate changes in sublingual microcirculation induced by a marathon race. Thirteen healthy male controls and 13 male marathon runners volunteered for the study. We performed sublingual microcirculation, using a Cytocam-IDF device (Braedius Medical, Huizen, Netherlands), and systemic hemodynamic measurements four times: 24 hours prior to their participation in the Kaunas Marathon (distance: 41.2 km), directly after finishing the marathon, 24 hours after the marathon, and one week after the marathon. The marathon runners exhibited a higher functional capillary density (FCD) and total vascular density of small vessels at the first visit compared with the controls. Overall, we did not find any changes in sublingual microcirculation of the marathon runners at any of the other visits. However, in a subgroup of marathon runners with a decreased FCD compared to the subgroup with increased FCD, the subgroup with decreased FCD had shorter running time (190.37 ± 30.2 versus 221.80 ± 23.4 min, p = 0.045), ingested less fluids (907 ± 615 versus 1950 ± 488 mL, p = 0.007) during the race, and lost much more weight (-2.4 ± 1.3 versus -1.0 ± 0.8 kg, p = 0.041). Recreational marathon running is not associated with an alteration of sublingual microcirculation. However, faster running and dehydration may be crucial for further impairing microcirculation.

  6. Time Evolution of Sublingual Microcirculatory Changes in Recreational Marathon Runners

    Directory of Open Access Journals (Sweden)

    Andrius Pranskunas

    2017-01-01

    Full Text Available We aimed to evaluate changes in sublingual microcirculation induced by a marathon race. Thirteen healthy male controls and 13 male marathon runners volunteered for the study. We performed sublingual microcirculation, using a Cytocam-IDF device (Braedius Medical, Huizen, Netherlands, and systemic hemodynamic measurements four times: 24 hours prior to their participation in the Kaunas Marathon (distance: 41.2 km, directly after finishing the marathon, 24 hours after the marathon, and one week after the marathon. The marathon runners exhibited a higher functional capillary density (FCD and total vascular density of small vessels at the first visit compared with the controls. Overall, we did not find any changes in sublingual microcirculation of the marathon runners at any of the other visits. However, in a subgroup of marathon runners with a decreased FCD compared to the subgroup with increased FCD, the subgroup with decreased FCD had shorter running time (190.37±30.2 versus 221.80±23.4 min, p=0.045, ingested less fluids (907±615 versus 1950±488 mL, p=0.007 during the race, and lost much more weight (-2.4±1.3 versus -1.0±0.8 kg, p=0.041. Recreational marathon running is not associated with an alteration of sublingual microcirculation. However, faster running and dehydration may be crucial for further impairing microcirculation.

  7. Microbiomes: unifying animal and plant systems through the lens of community ecology theory

    OpenAIRE

    Christian, Natalie; Whitaker, Briana K.; Clay, Keith

    2015-01-01

    The field of microbiome research is arguably one of the fastest growing in biology. Bacteria feature prominently in studies on animal health, but fungi appear to be the more prominent functional symbionts for plants. Despite the similarities in the ecological organization and evolutionary importance of animal-bacterial and plant–fungal microbiomes, there is a general failure across disciplines to integrate the advances made in each system. Researchers studying bacterial symbionts in animals b...

  8. Microbiomes: unifying animal and plant systems through the lens of community ecology theory.

    Science.gov (United States)

    Christian, Natalie; Whitaker, Briana K; Clay, Keith

    2015-01-01

    The field of microbiome research is arguably one of the fastest growing in biology. Bacteria feature prominently in studies on animal health, but fungi appear to be the more prominent functional symbionts for plants. Despite the similarities in the ecological organization and evolutionary importance of animal-bacterial and plant-fungal microbiomes, there is a general failure across disciplines to integrate the advances made in each system. Researchers studying bacterial symbionts in animals benefit from greater access to efficient sequencing pipelines and taxonomic reference databases, perhaps due to high medical and veterinary interest. However, researchers studying plant-fungal symbionts benefit from the relative tractability of fungi under laboratory conditions and ease of cultivation. Thus each system has strengths to offer, but both suffer from the lack of a common conceptual framework. We argue that community ecology best illuminates complex species interactions across space and time. In this synthesis we compare and contrast the animal-bacterial and plant-fungal microbiomes using six core theories in community ecology (i.e., succession, community assembly, metacommunities, multi-trophic interactions, disturbance, restoration). The examples and questions raised are meant to spark discussion amongst biologists and lead to the integration of these two systems, as well as more informative, manipulatory experiments on microbiomes research.

  9. Microbiomes: unifying animal and plant systems through the lens of community ecology theory

    Directory of Open Access Journals (Sweden)

    Natalie eChristian

    2015-09-01

    Full Text Available The field of microbiome research is arguably one of the fastest growing in biology. Bacteria feature prominently in studies on animal health, but fungi appear to be the more prominent functional symbionts for plants. Despite the similarities in the ecological organization and evolutionary importance of animal-bacterial and plant-fungal microbiomes, there is a general failure across disciplines to integrate the advances made in each system. Researchers studying bacterial symbionts in animals benefit from greater access to efficient sequencing pipelines and taxonomic reference databases, perhaps due to high medical and veterinary interest. However, researchers studying plant-fungal symbionts benefit from the relative tractability of fungi under laboratory conditions and ease of cultivation. Thus each system has strengths to offer, but both suffer from the lack of a common conceptual framework. We argue that community ecology best illuminates complex species interactions across space and time. In this synthesis we compare and contrast the animal-bacterial and plant-fungal microbiomes using six core theories in community ecology (i.e., succession, community assembly, metacommunities, multi-trophic interactions, disturbance, restoration. The examples and questions raised are meant to spark discussion amongst biologists and lead to the integration of these two systems, as well as more informative, manipulatory experiments on microbiomes research.

  10. Applying a global justice lens to health systems research ethics: an initial exploration.

    Science.gov (United States)

    Pratt, Bridget; Hyder, Adnan A

    2015-03-01

    Recent scholarship has considered what, if anything, rich people owe to poor people to achieve justice in global health and the implications of this for international research. Yet this work has primarily focused on international clinical research. Health systems research is increasingly being performed in low and middle income countries and is essential to reducing global health disparities. This paper provides an initial description of the ethical issues related to priority setting, capacity-building, and the provision of post-study benefits that arise during the conduct of such research. It presents a selection of issues discussed in the health systems research literature and argues that they constitute ethical concerns based on their being inconsistent with a particular theory of global justice (the health capability paradigm). Issues identified include the fact that priority setting for health systems research at the global level is often not driven by national priorities and that capacity-building efforts frequently utilize one-size-fits-all approaches.

  11. Microbiomes: unifying animal and plant systems through the lens of community ecology theory

    Science.gov (United States)

    Christian, Natalie; Whitaker, Briana K.; Clay, Keith

    2015-01-01

    The field of microbiome research is arguably one of the fastest growing in biology. Bacteria feature prominently in studies on animal health, but fungi appear to be the more prominent functional symbionts for plants. Despite the similarities in the ecological organization and evolutionary importance of animal-bacterial and plant–fungal microbiomes, there is a general failure across disciplines to integrate the advances made in each system. Researchers studying bacterial symbionts in animals benefit from greater access to efficient sequencing pipelines and taxonomic reference databases, perhaps due to high medical and veterinary interest. However, researchers studying plant–fungal symbionts benefit from the relative tractability of fungi under laboratory conditions and ease of cultivation. Thus each system has strengths to offer, but both suffer from the lack of a common conceptual framework. We argue that community ecology best illuminates complex species interactions across space and time. In this synthesis we compare and contrast the animal-bacterial and plant–fungal microbiomes using six core theories in community ecology (i.e., succession, community assembly, metacommunities, multi-trophic interactions, disturbance, restoration). The examples and questions raised are meant to spark discussion amongst biologists and lead to the integration of these two systems, as well as more informative, manipulatory experiments on microbiomes research. PMID:26441846

  12. KNOWLEDGE CONVERSION PADA PROSES PERENCANAAN PROYEK DI PT. LEN RAILWAY SYSTEM UNTUK STANDARDISASI PROSES DENGAN METODE SECI

    Directory of Open Access Journals (Sweden)

    Atikah Sayyidatu Nisaa

    2013-04-01

    Full Text Available PT LEN Railway System bergerak pada pembangunan proyek pensinyalan kereta api, namun pada proses perencanaan proyek pada perusahaan tersebut masih berupa tacit knowledge (pengalaman pekerja yang akan hilang. Oleh karena itu, diperlukan adanya konversi knowledge pekerja yang masih berbentuk tacit knowledge menjadi knowledge yang terdokumentasikan ke dalam bentuk explicit knowledge. Penelitian ini menggunakan metode SECI (Socialization, Externalization, Combination, Internalization. Pada tahap socialization dilakukan eksplorasi data kepada pelaku proyek yang bersangkutan mengenai proses bisnis suatu aktivitas maupun tacit dan explicit knowledge dari masing-masing aktivitas. Pada tahap externalization dilakukan pendokumentasian dari hasil eksplorasi data. Pada tahap combination dilakukan pemilihan best practice dengan menggunakan beberapa tools yaitu: metode Delphi, metode AHP dan pemilihan best practice menggunakan metode factor rating. Best practice yang didapatkan akan dikombinasikan dengan proses aktivitas dari PMBOK. Pada tahap internalization dilakukan penginformasian kepada pekerja mengenai best practice yang telah didapatkan dari hasil penelitian. Best practice yang terpilih dari hasil perhitungan factor rating didapatkan sebagai berikut best practice pembuatan WBS adalah proses bisnis dari responden 2 dengan nilai sebesar 8,710, untuk penentuan jadwal proyek dari responden 2 dengan nilai sebesar 8,067, untuk penentuan biaya proyek dari responden 3 sebesar 9,554, untuk pemilihan supplier dari responden 1 sebesar 8,330, untuk pembuatan desain proyek dari responden 1 sebesar 8,368 dan untuk pengadaan barang dari responden 1 dengan nilai sebesar 8,195. Kata Kunci : knowledge conversion, knowledge management, metode SECI Abstract The economic foundation movement of industrial era into the knowledge era has involved the project PT LEN Railway System which operates in the construction of the railway signaling project. This research uses SECI

  13. [Contact lens care and maintenance].

    Science.gov (United States)

    Bloise, L

    2017-04-01

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

  14. Prediction of imminent amputation in patients with non-reconstructible leg ischemia by means of microcirculatory investigations

    NARCIS (Netherlands)

    Ubbink, D. T.; Spincemaille, G. H.; Reneman, R. S.; Jacobs, M. J.

    1999-01-01

    We investigated the usefulness of skin microcirculatory investigations to predict imminent major amputation in patients with non-reconstructible critical limb ischemia. One hundred eleven patients with non-reconstructible chronic rest pain or small ulcers and an ankle blood pressure of 50 mm Hg or

  15. Ontogeny and Evolution Through the Lens of the Developmental Systems Theory (DST

    Directory of Open Access Journals (Sweden)

    Vicente Dressino

    2017-09-01

    Full Text Available The Developmental Systems Theory (DST intends to make a conceptual summary that links ontogenic development to evolution. This theory’s background may be found in the works of Waddington and Bertalanffy, who provided the foundations for the canalization of development and the biological systems theory, respectively. The aim of this work is to make a preliminary conceptual analysis of DST as a theoretical framework for developmental biology in particular and for evolutionary biology in general. For that purpose, we will take into account some of the concepts and proposals that constitute this framework, and we will work with secondary data obtained from the bibliography. We conclude that: 1. DST is able to argue against the gene centrist vision about the explanations that try to justify biological and evolutionary development; 2. DST argues coherently in favor of the role of Epigenetics in ontogeny and evolution; 3. In connection to that, the role of natural selection is restricted to a secondary plane; 4. DST proposes that the nature/nurture dichotomy must be overcome; and 5. DST constitutes a possible methodological research program composed of a series of not necessarily related hypothesis, theories, and methods that may be confirmed in a relatively independent manner from the rest of the theoretical network.

  16. Clustering Algorithms in Hybrid Recommender System on MovieLens Data

    Directory of Open Access Journals (Sweden)

    Kuzelewska Urszula

    2014-08-01

    Full Text Available Decisions are taken by humans very often during professional as well as leisure activities. It is particularly evident during surfing the Internet: selecting web sites to explore, choosing needed information in search engine results or deciding which product to buy in an on-line store. Recommender systems are electronic applications, the aim of which is to support humans in this decision making process. They are widely used in many applications: adaptive WWW servers, e-learning, music and video preferences, internet stores etc. In on-line solutions, such as e-shops or libraries, the aim of recommendations is to show customers the products which they are probably interested in. As input data the following are taken: shopping basket archives, ratings of the products or servers log files.

  17. Computer simulations for intense continuous beam transport in electrostatic lens systems

    International Nuclear Information System (INIS)

    Zhao Xiaosong; Lv Jianqin

    2008-01-01

    A code LEADS based on the Lie algebraic analysis for the continuous beam dynamics with space charge effect in beam transport has been developed. The program is used for the simulations of axial-symmetric and unsymmetrical intense continuous beam in the channels including drift spaces, electrostatic lenses and DC electrostatic accelerating tubes. In order to get the accuracy required, all elements are divided into many small segments, and the electric field in the segments is regarded as uniform field, and the dividing points are treated as thin lenses. Iteration procedures are adopted in the program to obtain self-consistent solutions. The code can be used in the designs of low energy beam transport systems, electrostatic accelerators and ion implantation machines. (authors)

  18. 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.

  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. Experimental investigation of a multi-stage humidification-dehumidification desalination system heated directly by a cylindrical Fresnel lens solar concentrator

    International Nuclear Information System (INIS)

    Wu, Gang; Zheng, Hongfei; Ma, Xinglong; Kutlu, Cagri; Su, Yuehong

    2017-01-01

    Highlights: • A solar desalination system heated directly by curved Fresnel lens concentrator. • Desalination system is based on the humidification-dehumidification process. • Four-stage multi-effect desalination system is proposed. • Condensation latent heat and residual heat in the brine are recycled and reutilized. • The maximum yield and GOR of the unit can reach 3.4 kg/h and 2.1, respectively. - Abstract: This study demonstrates a multi-stage humidification-dehumidification (HDH) solar desalination system heated directly by a cylindrical Fresnel lens concentrator. In this novel system, the solar radiation is sent directly into desalination unit. That is to say, the solar receiver and the evaporator of the system are a whole in which the black fillers in seawater directly absorb the concentrated solar lights to heat the seawater film to produce the evaporation. The configuration and working processes of the proposed design are described in detail. In order to analyze its performance, a small solar desalination prototype unit incorporated with a cylindrical Fresnel lens concentrator was designed and built in our laboratory. Using three-stage isothermal tandem heating mode, the variation of the fresh water yield rate and the absorber temperature with time were measured experimentally and were compared with theoretical calculations. The experimental results show that the maximum yield of the unit is about 3.4 kg/h, the maximum gained output ratio (GOR) is about 2.1, when the average intensity of solar radiation is about 867 W/m 2 . This study indicates that the proposed system has the characteristics of compact structure and GOR high. It still can be improved when the design and operation are optimized further.

  1. 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

  2. Kiloparsec Mass/Light Offsets in the Galaxy Pair-Ly$\\alpha$ Emitter Lens System SDSS\\,J1011$+$0143

    OpenAIRE

    Shu, Yiping; Bolton, Adam S.; Moustakas, Leonidas A.; Stern, Daniel; Dey, Arjun; Brownstein, Joel R.; Burles, Scott; Spinrad, Hyron

    2016-01-01

    We report the discovery of significant mass/light offsets in the strong gravitational lensing system SDSS\\,J1011$+$0143. We use the high-resolution \\textsl{Hubble Space Telescope} (\\textsl{HST}) F555W- and F814W-band imaging and Sloan Digital Sky Survey (SDSS) spectroscopy of this system, which consists of a close galaxy pair with a projected separation of $\\approx 4.2$ kpc at $z_{\\rm lens} \\sim 0.331$ lensing a Ly$\\alpha$ emitter (LAE) at $z_{\\rm source} = 2.701$. Comparisons between the mas...

  3. [Biophysical methods in assessment of the skin microcirculation system].

    Science.gov (United States)

    Dynnik, O B; Mostovoĭ, S E; Berezovskiĭ, V A

    2008-01-01

    In this work has been analyzed the potential of biophysics methods in estimations of the microcirculatory system. Capillaroresistometry, Computer capillaroscopy and Laser Doppler Flowmetry can to detect of the endothelial dysfunction in the patients with chronic hepatic diseases. This instrumentals biophysics methods may be used in clinical investigations for screening early pathological conditions with dysfunction of the microcirculatory system. The methods Laser Doppler Flowmetry is important for investigations the patients with others diseases and for dynamical monitoring by quality of the treatment. The purpose of these methods an objective estimation of disorders in the microcirculatory system.

  4. Endothelial TLR4 activation impairs intestinal microcirculatory perfusion in necrotizing enterocolitis via eNOS-NO-nitrite signaling.

    Science.gov (United States)

    Yazji, Ibrahim; Sodhi, Chhinder P; Lee, Elizabeth K; Good, Misty; Egan, Charlotte E; Afrazi, Amin; Neal, Matthew D; Jia, Hongpeng; Lin, Joyce; Ma, Congrong; Branca, Maria F; Prindle, Thomas; Richardson, Ward M; Ozolek, John; Billiar, Timothy R; Binion, David G; Gladwin, Mark T; Hackam, David J

    2013-06-04

    Necrotizing enterocolitis (NEC) is a devastating disease of premature infants characterized by severe intestinal necrosis and for which breast milk represents the most effective protective strategy. Previous studies have revealed a critical role for the lipopolysaccharide receptor toll-like receptor 4 (TLR4) in NEC development through its induction of mucosal injury, yet the reasons for which intestinal ischemia in NEC occurs in the first place remain unknown. We hypothesize that TLR4 signaling within the endothelium plays an essential role in NEC development by regulating perfusion to the small intestine via the vasodilatory molecule endothelial nitric oxide synthase (eNOS). Using a unique mouse system in which we selectively deleted TLR4 from the endothelium, we now show that endothelial TLR4 activation is required for NEC development and that endothelial TLR4 activation impairs intestinal perfusion without effects on other organs and reduces eNOS expression via activation of myeloid differentiation primary response gene 88. NEC severity was significantly increased in eNOS(-/-) mice and decreased upon administration of the phosphodiesterase inhibitor sildenafil, which augments eNOS function. Strikingly, compared with formula, human and mouse breast milk were enriched in sodium nitrate--a precursor for enteral generation of nitrite and nitric oxide--and repletion of formula with sodium nitrate/nitrite restored intestinal perfusion, reversed the deleterious effects of endothelial TLR4 signaling, and reduced NEC severity. These data identify that endothelial TLR4 critically regulates intestinal perfusion leading to NEC and reveal that the protective properties of breast milk involve enhanced intestinal microcirculatory integrity via augmentation of nitrate-nitrite-NO signaling.

  5. Endothelial TLR4 activation impairs intestinal microcirculatory perfusion in necrotizing enterocolitis via eNOS–NO–nitrite signaling

    Science.gov (United States)

    Yazji, Ibrahim; Sodhi, Chhinder P.; Lee, Elizabeth K.; Good, Misty; Egan, Charlotte E.; Afrazi, Amin; Neal, Matthew D.; Jia, Hongpeng; Lin, Joyce; Branca, Maria F.; Prindle, Thomas; Richardson, Ward M.; Ozolek, John; Billiar, Timothy R.; Binion, David G.; Gladwin, Mark T.; Hackam, David J.

    2013-01-01

    Necrotizing enterocolitis (NEC) is a devastating disease of premature infants characterized by severe intestinal necrosis and for which breast milk represents the most effective protective strategy. Previous studies have revealed a critical role for the lipopolysaccharide receptor toll-like receptor 4 (TLR4) in NEC development through its induction of mucosal injury, yet the reasons for which intestinal ischemia in NEC occurs in the first place remain unknown. We hypothesize that TLR4 signaling within the endothelium plays an essential role in NEC development by regulating perfusion to the small intestine via the vasodilatory molecule endothelial nitric oxide synthase (eNOS). Using a unique mouse system in which we selectively deleted TLR4 from the endothelium, we now show that endothelial TLR4 activation is required for NEC development and that endothelial TLR4 activation impairs intestinal perfusion without effects on other organs and reduces eNOS expression via activation of myeloid differentiation primary response gene 88. NEC severity was significantly increased in eNOS−/− mice and decreased upon administration of the phosphodiesterase inhibitor sildenafil, which augments eNOS function. Strikingly, compared with formula, human and mouse breast milk were enriched in sodium nitrate—a precursor for enteral generation of nitrite and nitric oxide—and repletion of formula with sodium nitrate/nitrite restored intestinal perfusion, reversed the deleterious effects of endothelial TLR4 signaling, and reduced NEC severity. These data identify that endothelial TLR4 critically regulates intestinal perfusion leading to NEC and reveal that the protective properties of breast milk involve enhanced intestinal microcirculatory integrity via augmentation of nitrate–nitrite–NO signaling. PMID:23650378

  6. Structural Conditions for Collaboration and Learning in Innovation Networks: Using an Innovation System Performance Lens to Analyse Agricultural Knowledge Systems

    NARCIS (Netherlands)

    Hermans, F.; Klerkx, L.W.A.; Roep, D.

    2015-01-01

    Purpose: We investigate how the structural conditions of eight different European agricultural innovation systems can facilitate or hinder collaboration and social learning in multidisciplinary innovation networks. Methodology: We have adapted the Innovation System Failure Matrix to investigate the

  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. Effective X-ray beam size measurements of an X-ray tube and polycapillary X-ray lens system using a scanning X-ray fluorescence method

    Energy Technology Data Exchange (ETDEWEB)

    Gherase, Mihai R., E-mail: mgherase@csufresno.edu; Vargas, Andres Felipe

    2017-03-15

    Size measurements of an X-ray beam produced by an integrated polycapillary X-ray lens (PXL) and X-ray tube system were performed by means of a scanning X-ray fluorescence (SXRF) method using three different metallic wires. The beam size was obtained by fitting the SXRF data with the analytical convolution between a Gaussian and a constant functions. For each chemical element in the wire an effective energy was calculated based on the incident X-ray spectrum and its photoelectric cross section. The proposed method can be used to measure the effective X-ray beam size in XRF microscopy studies.

  9. Improvement of Varioptic's liquid lens based on electrowetting: how to obtain a short response time and its application in the design of a high resolution iris biometric system

    Science.gov (United States)

    Burger, Benjamin; Meimon, Serge C.; Petit, Cyril; Nguyen, Minh Chau

    2015-02-01

    This communication presents the results obtained for decreasing the response time of electrowetting-based real time focus correctors (liquid lenses). In order to provide a compact iris biometric system demonstrator, we have achieved a response time at 90% of 7.5 ms for a change in focalization from 0 diopter to 10 diopter with a liquid lens having an aperture of 1.9 mm. We have used a hydrodynamic fluid reorganization model to predict the features of these fast liquid lenses and evaluated the sensivity of the response time to the different conception parameters.

  10. Structural Conditions for Collaboration and Learning in Innovation Networks: Using an Innovation System Performance Lens to Analyse Agricultural Knowledge Systems

    Science.gov (United States)

    Hermans, Frans; Klerkx, Laurens; Roep, Dirk

    2015-01-01

    Purpose: We investigate how the structural conditions of eight different European agricultural innovation systems can facilitate or hinder collaboration and social learning in multidisciplinary innovation networks. Methodology: We have adapted the Innovation System Failure Matrix to investigate the main barriers and enablers eight countries…

  11. 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.

  12. 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.

  13. Experimental Investigation on the Feasibility of Using a Fresnel Lens as a Solar-Energy Collection System for Enhancing On-Orbit Power Generation Performance

    Directory of Open Access Journals (Sweden)

    Tae-Yong Park

    2017-01-01

    Full Text Available Cube satellites have a limitation for generating power because of their cubic structure and extremely small size. In addition, the incidence angle between the sun and the solar panels continuously varies owing to the revolution and rotation of the satellite according to the attitude control strategy. This angle is an important parameter for determining the power generation performance of the cube satellite. In this study, we performed an experimental feasibility study that uses a Fresnel lens as a solar-energy collection system for cube satellite applications, so that the power generation efficiency can be enhanced under the worst incidence angle condition between the sun and solar panels by concentrating and redirecting solar energy onto the solar panels with a commercial Fresnel lens. To verify the effectiveness of the proposed system, we conducted a power-measurement test using a solar simulator and Fresnel lenses at various angles to the light source. In addition, we predicted the on-orbit power-generation enhancement achieved by employing the solar-energy collection system with various attitude control strategies.

  14. Numerical studies of triplet and Russian quadruplet quadrupole lens systems with the given spot size on the target, for use in a microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Brazhnik, V.A.; Lebed, S.A.; Ponomarev, A.G.; Storizhko, V.E. [Ukrainian Academy of Sciences, Sumy (Ukraine). Applied Physics Institute; Dymnikov, A.D. [University of St Petersburg, Stary (Russian Federation). Institute of Computational Mathematics and Control Processes; Jamieson, D.N.; Legge, S.A. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1993-12-31

    In a nuclear microprobe the focusing system is an essential component which determines the beam spot size, i.e. the microprobe resolution. A small beam cross section at the target is the most important of the many conflicting requirements imposed on the beam The second most important factor is the current of the beam which at the given brightness is proportional to the phase volume (or emittance) of the beam. Existing microprobes frequently use a triplet or a Russian quadruplet as the focusing systems. This paper describes the numerical studies of some optimal quadrupole lens systems consisting of three or four lenses suitable for use in a nuclear microprobe taking into account geometrical aberrations of third order. The maximum emittance of changed particle beams for these systems has been found. It is shown how the maximum emittance depends on the spot size. 2 refs., 2 figs.

  15. Numerical studies of triplet and Russian quadruplet quadrupole lens systems with the given spot size on the target, for use in a microprobe

    International Nuclear Information System (INIS)

    Brazhnik, V.A.; Lebed, S.A.; Ponomarev, A.G.; Storizhko, V.E.; Dymnikov, A.D.; Jamieson, D.N.; Legge, S.A.

    1993-01-01

    In a nuclear microprobe the focusing system is an essential component which determines the beam spot size, i.e. the microprobe resolution. A small beam cross section at the target is the most important of the many conflicting requirements imposed on the beam The second most important factor is the current of the beam which at the given brightness is proportional to the phase volume (or emittance) of the beam. Existing microprobes frequently use a triplet or a Russian quadruplet as the focusing systems. This paper describes the numerical studies of some optimal quadrupole lens systems consisting of three or four lenses suitable for use in a nuclear microprobe taking into account geometrical aberrations of third order. The maximum emittance of changed particle beams for these systems has been found. It is shown how the maximum emittance depends on the spot size. 2 refs., 2 figs

  16. The Effects of Pancreatic Microcirculatory Disturbances on Histopathologic Tissue Damage and the Outcome in Severe Acute Pancreatitis.

    Science.gov (United States)

    Tomkötter, Lena; Erbes, Johannes; Trepte, Constantin; Hinsch, Andrea; Dupree, Anna; Bockhorn, Maximilian; Mann, Oliver; Izbicki, Jakob R; Bachmann, Kai

    2016-02-01

    Severe acute pancreatitis is an inflammatory disease of the pancreas with a high morbidity and mortality. To date, no causal treatment is known. The aim of the present study was to analyze the impact of pancreatic microcirculatory disturbances in severe acute pancreatitis and to correlate the effects with histopathologic tissue damage and outcome. Severe acute pancreatitis was induced in 129 pigs by injection of glycodeoxycholic acid into the pancreatic duct. Pancreatic microcirculation, pancreatic tissue oxygenation, histopathologic tissue damage, and survival were measured and analyzed. Our study demonstrates a strong correlation between pancreatic microcirculatory disturbances and histopathologic tissue damage (r = 0.728; P pancreatitis according to an established porcine pancreatitis score (r = 0.694; P pancreatic microcirculation were shown to be associated with an increased mortality rate in severe acute pancreatitis. We found that pancreatic microcirculatory disturbances have significant effects on histopathologic tissue damage and the outcome of severe acute pancreatitis. For a better survival of severe acute pancreatitis, the treatment should focus on an improvement of pancreatic microcirculation.

  17. 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.

  18. 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.

  19. Colored Contact Lens Dangers

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  20. 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. ...

  1. Colored Contact Lens Dangers

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  2. Colored Contact Lens Dangers

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  3. Colored Contact Lens Dangers

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    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 ...

  4. Colored Contact Lens Dangers

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  6. Colored Contact Lens Dangers

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  7. Colored Contact Lens Dangers

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    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 ...

  9. 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.

  10. Colored Contact Lens Dangers

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  11. Colored Contact Lens Dangers

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  12. Colored Contact Lens Dangers

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  13. Colored Contact Lens Dangers

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    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 ...

  14. Double lens collimator solar feedback sensor and master slave configuration: Development of compact and low cost two axis solar tracking system for CPV applications

    KAUST Repository

    Burhan, Muhammad

    2016-08-31

    The conventional CPV systems, as big unit design, are only suitable to be installed in the open regions, like desert areas. This gigantic system design restricts their use on the rooftop of commercial and residential buildings, unlike the conventional PV systems. This paper proposes a compact but highly accurate and cheap two axis solar tracking system, designed for CPV system field operation. The proposed system is designed and verified for tracking accuracy requirement of 0.3 degrees, and has maximum capability of as high as 0.1 degrees tracking accuracy. High tracking accuracy is ensured using in-house built double lens collimator solar feedback sensor, within a fraction of the cost of commercial solar tracking sensors. A hybrid tracking algorithm is developed in C-programming using astronomical and optical solar tracking methods. As compact CPV system design demands larger number of tracking units, for same power capacity of system. Therefore, a master slave control configuration is also proposed for the CPV field operation. Only master tracker will be equipped with the expensive tracking devices, while the required tracking information will be sent to all of the slave trackers using wireless communication through ZigBee devices. With detailed optical design, simulation and control strategy, a prototype of the proposed CPV tracking system is developed, experimentally investigated and verified for tracking accuracy for outdoor operation at the rooftop. (C) 2016 Elsevier Ltd. All rights reserved.

  15. 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

  16. Projection-type integral imaging system using a three-dimensional screen composed of a lens array and a retroreflector film.

    Science.gov (United States)

    Kim, Young Min; Song, Byoungsub; Min, Sung-Wook

    2017-05-01

    We propose an improved projection-type integral imaging system using a three-dimensional (3D) screen consisting of a lens array and a retroreflector film in this paper. The projection-type integral imaging system suffers from the disadvantage of low-visibility images because of the inherently small exit pupil size of the projector. In order to resolve this problem, we adopt a 3D screen to avoid the demerits of a diffuser screen, such as off-screen image blur and loss of parallax. To determine the appropriate configuration of the 3D screen in the system, a simulation based on a ray transfer matrix analysis method was performed. The results show that the 3D screen should be located near the central depth plane of the integral imaging system, which leads to the conclusion that only the real mode is available for the proposed system. Experiments to verify this configuration and the feasibility of the proposed system were conducted using a system constructed with a real mode integral imaging system including a convex mirror array, which can fundamentally eliminate the pseudoscopic problem.

  17. 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

  18. [Microcirculatory consequences of a venous striction in the rat. Effect of a coumarine-rutine association].

    Science.gov (United States)

    Laemmel, E; Stücker, O; Pons, C; Duverger, J P; Dedieu, F; Leutenegger, E

    1998-06-01

    The aim of this study was to investigate the consequences of a venous striction on capillary red blood cell distribution and venular blood return and the effect of a coumarin derivative-rutoside combination. The study was conducted, in vivo, in the rat cremaster muscle using intravital microscopy. The striction lasted thirty minutes and was obtained by clamping the epigastric vein. This mechanical constraint was sufficient to induce microcirculatory modifications without disrupting microvessels. Before the striction (t-5 min), the velocities and diameters of the veins and arteries were comparable in all groups. After the striction (t5 min), in the control group, venous blood flow decreased by 60%, from 0.48 +/- 0.09 mm3/s (t-5 min) to 0.20 +/- 0.06 mm3/s (t5 min). The results showed that after thirty minutes reperfusion, venular blood flow in the control animals was only 34% of initial blood flow. The mean red blood cell velocity dropped by 56%, the percentage of low perfused capillaries increased from 7.5% to 50%. Treatment of animals with a coumarin derivative-rutoside combination, particularly at 4 mg/kg coumarin derivative-100 mg/kg rutoside, has significantly improved the microcirculation. After thirty minutes reperfusion venular blood flow was 60% and the percentage of low perfused capillaries was only 10%. The effect seemed to be more pronounced for rutoside than coumarin derivatives. The interest of this study was to set up an experimental model of a venous striction not too severe to induce micro-hemorrages but enough to modify microcirculation. This model was used to quantify the beneficial effects of a coumarin derivative-rutoside combination.

  19. Impact of microcirculatory video quality on the evaluation of sublingual microcirculation in critically ill patients.

    Science.gov (United States)

    Damiani, Elisa; Ince, Can; Scorcella, Claudia; Domizi, Roberta; Carsetti, Andrea; Mininno, Nicoletta; Pierantozzi, Silvia; Adrario, Erica; Romano, Rocco; Pelaia, Paolo; Donati, Abele

    2017-10-01

    We aimed to assess the impact of image quality on microcirculatory evaluation with sidestream dark-field (SDF) videomicroscopy in critically ill patients and explore factors associated with low video quality. This was a retrospective analysis of a single-centre prospective observational study. Videos of the sublingual microcirculation were recorded using SDF videomicroscopy in 100 adult patients within 12 h from admittance to the intensive care unit and every 24 h until discharge/death. Parameters of vessel density and perfusion were calculated offline for small vessels. For all videos, a quality score (-12 = unacceptable, 1 = suboptimal, 2 = optimal) was assigned for brightness, focus, content, stability, pressure and duration. Videos with a total score ≤8 were deemed as unacceptable. A total of 2455 videos (853 triplets) was analysed. Quality was acceptable in 56 % of videos. Lower quality was associated with worse microvascular density and perfusion. Unreliable triplets (≥1 unacceptable or missing video, 65 % of total) showed lower vessel density, worse perfusion and higher flow heterogeneity as compared to reliable triplets (p Quality was higher among triplets collected by an extensively-experienced investigator or in patients receiving sedation or mechanical ventilation. Perfused vessel density was higher in patients with Glasgow Coma Scale (GCS) ≤8 (18.9 ± 4.5 vs. 17.0 ± 3.9 mm/mm 2 in those with GCS >8, p quality depends on both the operator's experience and patient's cooperation. Low-quality videos may produce spurious data, leading to an overestimation of microvascular alterations.

  20. CORRECTION OF MICROCIRCULATORY DISORDERS IN NON-ALCOHOLIC FATTY LIVER DISEASE IN PATIENTS WITH CHRONIC HEART FAILURE PATIENTS

    Directory of Open Access Journals (Sweden)

    M. E. Statsenko

    2016-01-01

    Full Text Available Combined liver damage in patients with chronic heart failure and non-alcoholic fatty liver disease leads to the formation of pathological hemodynamic types of microcirculation with prevalence of shunt blood flow, nutritional deficiency, that correlated with changes in the functional state of the liver. Using cytoprotector mexicor for 16 weeks as part of the basic treatment of patients with chronic heart failure and non-alcoholic fatty liver disease can correct these microcirculatory disorders, has a beneficial effect on endothelial function, autonomic tone of microvessels, which is accompanied by the positive dynamics of indicators of cytolysis and cholestasis.

  1. 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

  2. Impact of eight weeks of repeated ischaemic preconditioning on brachial artery and cutaneous microcirculatory function in healthy males.

    Science.gov (United States)

    Jones, Helen; Nyakayiru, Jean; Bailey, Tom G; Green, Daniel J; Cable, N Timothy; Sprung, Victoria S; Hopkins, Nicola D; Thijssen, Dick H J

    2015-08-01

    Ischaemic preconditioning has well-established cardiac and vascular protective effects. Short interventions (one week) of daily ischaemic preconditioning episodes improve conduit and microcirculatory function. This study examined whether a longer (eight weeks) and less frequent (three per week) protocol of repeated ischaemic preconditioning improves vascular function. Eighteen males were randomly allocated to either ischaemic preconditioning (22.4 ± 2.3 years, 23.7 ± 3.1 kg/m(2)) or a control intervention (26.0 ± 4.8 years, 26.4 ± 1.9 kg/m(2)). Brachial artery endothelial-dependent (FMD), forearm cutaneous microvascular function and cardiorespiratory fitness were assessed at zero, two and eight weeks. A greater improvement in FMD was evident following ischaemic preconditioning training compared with control at weeks 2 (2.24% (0.40, 4.08); p=0.02) and 8 (1.11% (0.13, 2.10); p=0.03). Repeated ischaemic preconditioning did not change cutaneous microcirculatory function or fitness. These data indicate that a feasible and practical protocol of regular ischaemic preconditioning episodes improves endothelial function in healthy individuals within two weeks, and these effects persist following repeated ischaemic preconditioning for eight weeks. © The European Society of Cardiology 2014.

  3. 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.

  4. 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,

  5. Hyperspectral Imaging as an Early Biomarker for Radiation Exposure and Microcirculatory Damage

    Directory of Open Access Journals (Sweden)

    Michael S. Chin

    2015-10-01

    Full Text Available BACKGROUND: Radiation exposure can lead to detrimental effects in skin microcirculation. The precise relationship between radiation dose received and its effect on cutaneous perfusion still remains controversial. Previously, we have shown that hyperspectral imaging (HSI is able to demonstrate long-term reductions in cutaneous perfusion secondary to chronic microvascular injury. This study characterizes the changes in skin microcirculation in response to varying doses of ionizing radiation and investigates these microcirculatory changes as a possible early non-invasive biomarker that may correlate with the extent of long-term microvascular damage.METHODS: Immunocompetent hairless mice (n=66 were exposed to single fractions of superficial beta-irradiation in doses of 0, 5, 10, 20, 35, or 50 Gy. A HSI device was utilized to measure deoxygenated hemoglobin levels in irradiated and control areas. HSI measurements were performed at baseline before radiation exposure and for the first three days post-irradiation. Maximum macroscopic skin reactions were graded, and histological assessment of cutaneous microvascular densities at four weeks post-irradiation was performed in harvested tissue by CD31 immunohistochemistry.RESULTS: CD31 immunohistochemistry demonstrated a significant correlation (r=0.90, p<0.0001 between dose and vessel density reduction at four weeks. Using HSI analysis, early changes in deoxygenated hemoglobin levels were observed during the first three days post-irradiation in all groups. These deoxygenated hemoglobin changes varied proportionally with dose (r=0.98, p<0.0001 and skin reactions (r=0.98, p<0.0001. There was a highly significant correlation (r= 0.91, p<0.0001 between these early changes in deoxygenated hemoglobin and late vascular injury severity assessed at the end of four weeks.CONCLUSIONS: Radiation dose is directly correlated with cutaneous microvascular injury severity at four weeks in our model. Early post

  6. 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

  7. 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 ...

  8. 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 ...

  9. 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

  10. 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…

  11. 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 ...

  12. 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.

  13. 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.

  14. 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 ...

  15. Biopsy Diagnosis of Oral Carcinoma by the Combination of Morphological and Spectral Methods Based on Embedded Relay Lens Microscopic Hyperspectral Imaging System.

    Science.gov (United States)

    Ou-Yang, Mang; Hsieh, Yao-Fang; Lee, Cheng-Chung

    Cytopathological examination through biopsy is very important for carcinoma detection. The embedded relay lens microscopic hyperspectral imaging system (ERL-MHIS) provides a morphological image of a biopsy sample and the spectrum of each pixel in the image simultaneously. Based on the ERL-MHIS, this work develops morphological and spectral methods to diagnose oral carcinoma biopsy. In morphological discrimination, the fractal dimension method is applied to differentiate between normal and abnormal tissues. In spectral identification, normal and cancerous cells are distinguished using five methods. However, the spectra of normal and cancerous cells vary with patient. The diagnostic performances of the five methods are thus not ideal. Hence, the proposed cocktail approach is used to determine the effectiveness of the spectral methods in correlating with the sampling conditions. And then we use a combination of effective spectral methods according to the sample conditions for diagnosing a sample. A total of 68 biopsies from 34 patients are analyzed using the ERL-MHIS. The results demonstrate a sensitivity of 90 ± 4.53 % and a specificity of 87.8 ± 5.21 %. Furthermore, in our survey, this system is the first time utilized to study oral carcinoma biopsies.

  16. Outdoor overall performance of a novel air-gap-lens-walled compound parabolic concentrator (ALCPC) incorporated with photovoltaic/thermal system

    International Nuclear Information System (INIS)

    Li, Guiqiang; Pei, Gang; Ji, Jie; Su, Yuehong

    2015-01-01

    Highlights: • A prototype of an ALCPC-PV/T system was designed and set up. • Good optical agreements were observed between simulation and experiment. • The effects of the temperature on the electrical characteristics were discussed. • The thermal performance for circulating cooling was analyzed. • The system efficiency was calculated to present the overall performance. - Abstract: A novel air-gap-lens-walled compound parabolic concentrator incorporated with photovoltaic/thermal system (ALCPC-PV/T) was proposed. The optical, electrical and thermal performances of the ALCPC-PV/T under the outdoor condition were analyzed for building integrated concentrating photovoltaic/thermal application. The simulation and experiment were carried out to reveal the optical characteristics of ALCPC-PV/T on two typical days. The experiment results verified the optical simulation results that the ALCPC-PV/T system had a half acceptance angle of 35° and an average optical efficiency of 83.0% within the half acceptance angle for direct incidence. Furthermore, the average optical efficiencies on the two typical days were all above 60% under the actual outdoor condition considering direct and diffuse solar radiation. Details of electrical characteristics affected by the temperature of circulating cooling water were also displayed. The electrical and thermal efficiencies of the ALCPC-PV/T system during the test were 6.0% and 35.0% respectively with the final water temperature of 70 °C. In addition, the fitted results indicated that under the zero reduced temperature condition, the thermal efficiency of the ALCPC PV/T system was 52.0%, and the corresponding electrical efficiency was 6.6%

  17. 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.

  18. 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.

  19. 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.

  20. Early microcirculatory impairment during therapeutic hypothermia is associated with poor outcome in post-cardiac arrest children: a prospective observational cohort study

    NARCIS (Netherlands)

    Buijs, Erik A. B.; Verboom, Elyse M.; Top, Anke P. C.; Andrinopoulou, Eleni-Rosalina; Buysse, Corinne M. P.; Ince, Can; Tibboel, Dick

    2014-01-01

    This study aimed to evaluate if the microcirculation is impaired during and after therapeutic hypothermia (TH) in children with return of spontaneous circulation after cardiac arrest (CA) and to assess if microcirculatory impairment predicts mortality. This has been reported for post-CA adults, but

  1. Distinct alterations in sublingual microcirculatory blood flow and hemoglobin oxygenation in on-pump and off-pump coronary artery bypass graft surgery

    NARCIS (Netherlands)

    Atasever, Bektaş; Boer, Christa; Goedhart, Peter; Biervliet, Jules; Seyffert, Jan; Speekenbrink, Ron; Schwarte, Lothar; de Mol, Bas; Ince, Can

    2011-01-01

    The authors hypothesized that cardiopulmonary bypass (CPB) (on-pump) is associated with more severe changes in the microcirculatory blood flow and tissue oxygenation as compared with off-pump coronary artery bypass surgery. An observational study. A university hospital and teaching hospital.

  2. 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.

  3. 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.

  4. Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart-Thornley Detector Systems.

    Science.gov (United States)

    Zhang, Xinming; Cen, Xi; Ravichandran, Rijuta; Hughes, Lauren A; van Benthem, Klaus

    2016-06-01

    The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart-Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron-specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart-Thornley detector.

  5. 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.

  6. [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.

  7. Hepatic microcirculatory failure Falência microcirculatória hepática

    Directory of Open Access Journals (Sweden)

    Fernando Silva Ramalho

    2006-01-01

    Full Text Available Liver ischemia has been considered a frequent problem in medical practice, and can be associated to a number of surgical and clinical situations, such as massive hepatic resections, sepsis, liver trauma, circulatory shock and liver transplantation. After restoring blood flow, the liver is further subjected to an additional injury more severe than that induced by ischemia. On account of the complexity of mechanisms related to pathophysiology of ischemia and reperfusion (I/R injury, this review deals with I/R effects on sinusoidal microcirculation, especially when steatosis is present. Alterations in hepatic microcirculation are pointed as a main factor to explain lower tolerance of fatty liver to ischemia-reperfusion insult. The employment of therapeutic strategies that interfere directly with vasoactive mediators (nitric oxide and endothelins acting on the sinusoidal perfusion seem to be determinant for the protection of the liver parenchyma against I/R. These approaches could be very suitable to take advantage of marginal specimens as fatty livers, in which the microcirculatory disarrangements hamper its employment in liver transplantation.A isquemia hepática é um problema relativamente freqüente na prática clínica, sobrevindo em situações diversas como ressecções hepáticas maciças, sepse, trauma hepático extenso, choque circulatório e transplante hepático. Durante a restauração do fluxo sanguíneo, o fígado é submetido a uma agressão adicional ainda mais intensa que aquela imposta pela isquemia. Devido à complexidade dos diversos mecanismos envolvidos na fisiopatologia da lesão por isquemia e reperfusão (I/R hepática, esta revisão se limitará a discorrer sobre os efeitos da I/R na microcirculação sinusoidal, com ênfase para as alterações microvasculares que tomam lugar no fígado esteatótico pós-isquêmico. O desarranjo microcirculatório é apontado como um importante fator para explicar a reduzida toler

  8. 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.

  9. 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.

  10. 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.

  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. 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.

  13. Different effects of the hypolipidemic drugs pravastatin and lovastatin on the cholesterol biosynthesis of the human ocular lens in organ culture and on the cholesterol content of the rat lens in vivo

    NARCIS (Netherlands)

    Vries, A.C.J. de; Cohen, L.H.

    1993-01-01

    This study aimed to investigate the influence of the hypocholesterolemic drugs pravastatin and lovastatin on the cholesterol biosynthesis in the ocular lens. Two model systems were used: a human lens organ culture system and an in vivo rat lens system. For measurements of cholesterol and fatty acid

  14. 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.

  15. Mesenteric microcirculatory dysfunctions and translocation of indigenous bacteria in a rat model of strangulated small bowel obstruction

    Directory of Open Access Journals (Sweden)

    Fernando Luiz Zanoni

    2009-01-01

    Full Text Available PRUPOSE: Bacterial translocation has been shown to occur in critically ill patients after extensive trauma, shock, sepsis, or thermal injury. The present study investigates mesenteric microcirculatory dysfunctions, the bacterial translocation phenomenon, and hemodynamic/metabolic disturbances in a rat model of intestinal obstruction and ischemia. METHODS: Anesthetized (pentobarbital 50 mg/kg, i.p. male Wistar rats (250-350 g were submitted to intestinal obstruction or laparotomy without intestinal obstruction (Sham and were evaluated 24 hours later. Bacterial translocation was assessed by bacterial culture of the mesenteric lymph nodes (MLN, liver, spleen, and blood. Leukocyte-endothelial interactions in the mesenteric microcirculation were assessed by intravital microscopy, and P-selectin and intercellular adhesion molecule (ICAM-1 expressions were quantified by immunohistochemistry. Hematocrit, blood gases, lactate, glucose, white blood cells, serum urea, creatinine, bilirubin, and hepatic enzymes were measured. RESULTS: About 86% of intestinal obstruction rats presented positive cultures for E. coli in samples of the mesenteric lymph nodes, liver, and spleen, and 57% had positive hemocultures. In comparison to the Sham rats, intestinal obstruction induced neutrophilia and increased the number of rolling (~2-fold, adherent (~5-fold, and migrated leukocytes (~11-fold; this increase was accompanied by an increased expression of P-selectin (~2-fold and intercellular adhesion molecule-1 (~2-fold in the mesenteric microcirculation. Intestinal obstruction rats exhibited decreased PaCO2, alkalosis, hyperlactatemia, and hyperglycemia, and increased blood potassium, hepatic enzyme activity, serum urea, creatinine, and bilirubin. A high mortality rate was observed after intestinal obstruction (83% at 72 h vs. 0% in Sham rats. CONCLUSION: Intestinal obstruction and ischemia in rats is a relevant model for the in vivo study of mesenteric microcirculatory

  16. School Systems' Practices of Controlling Socialization during Principal Succession: Looking through the Lens of an Organizational Socialization Theory

    Science.gov (United States)

    Bengtson, Ed; Zepeda, Sally J.; Parylo, Oksana

    2013-01-01

    The importance of effective school leadership is well known. The inevitable changing of school leaders raises concerns over the successfulness of the succession process. Directly linked to leader succession is socialization; therefore, the purpose of this study was to examine the processes and practices of school systems that control the…

  17. 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

  18. 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®.

  19. 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.

  20. Precision diagnosis: a view of the clinical decision support systems (CDSS) landscape through the lens of critical care.

    Science.gov (United States)

    Belard, Arnaud; Buchman, Timothy; Forsberg, Jonathan; Potter, Benjamin K; Dente, Christopher J; Kirk, Allan; Elster, Eric

    2017-04-01

    Improving diagnosis and treatment depends on clinical monitoring and computing. Clinical decision support systems (CDSS) have been in existence for over 50 years. While the literature points to positive impacts on quality and patient safety, outcomes, and the avoidance of medical errors, technical and regulatory challenges continue to retard their rate of integration into clinical care processes and thus delay the refinement of diagnoses towards personalized care. We conducted a systematic review of pertinent articles in the MEDLINE, US Department of Health and Human Services, Agency for Health Research and Quality, and US Food and Drug Administration databases, using a Boolean approach to combine terms germane to the discussion (clinical decision support, tools, systems, critical care, trauma, outcome, cost savings, NSQIP, APACHE, SOFA, ICU, and diagnostics). References were selected on the basis of both temporal and thematic relevance, and subsequently aggregated around four distinct themes: the uses of CDSS in the critical and surgical care settings, clinical insertion challenges, utilization leading to cost-savings, and regulatory concerns. Precision diagnosis is the accurate and timely explanation of each patient's health problem and further requires communication of that explanation to patients and surrogate decision-makers. Both accuracy and timeliness are essential to critical care, yet computed decision support systems (CDSS) are scarce. The limitation arises from the technical complexity associated with integrating and filtering large data sets from diverse sources. Provider mistrust and resistance coupled with the absence of clear guidance from regulatory bodies further retard acceptance of CDSS. While challenges to develop and deploy CDSS are substantial, the clinical, quality, and economic impacts warrant the effort, especially in disciplines requiring complex decision-making, such as critical and surgical care. Improving diagnosis in health care

  1. 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

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  2. 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

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  3. Narrative change in emotion-focused therapy: how is change constructed through the lens of the innovative moments coding system?

    Science.gov (United States)

    Mendes, Inês; Ribeiro, António P; Angus, Lynne; Greenberg, Leslie S; Sousa, Inês; Gonçalves, Miguel M

    2010-11-01

    The aim of this study was to advance understanding of how clients construct their own process of change in effective therapy sessions. Toward this end, the authors applied a narrative methodological tool for the study of the change process in emotion-focused therapy (EFT), replicating a previous study done with narrative therapy (NT). The Innovative Moments Coding System (IMCS) was applied to three good-outcome and three poor-outcome cases in EFT for depression to track the innovative moments (IMs), or exceptions to the problematic self-narrative, in the therapeutic conversation. IMCS allows tracking of five types of IMs events: action, reflection, protest, reconceptualization, and performing change. The analysis revealed significant differences between the good-outcome and poor-outcome groups regarding reconceptualization and performing change IMs, replicating the findings from a previous study. Reconceptualization and performing change IMs seem to be vital in the change process.

  4. 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.

  5. 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.

  6. 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

  7. Contact lens surface changes after exposure to surfactant and abrasive cleaning procedures.

    Science.gov (United States)

    Doell, G B; Palombi, D L; Egan, D J; Huff, J W

    1986-06-01

    Proper lens maintenance is required if contact lens wear is to be successful. Poor compliance or inadequate cleaning may lead to contact lens failures and potentially damage to the eye. With phase contrast microscopy, we addressed the effect of cleaning systems on the physical integrity of a surface-modified lens--the Silcon contact lens. Several cleaners were evaluated for their ability to clean Silcon lenses with minimal damage to the lens surface. The data demonstrated that: all cleaning techniques alter the surface appearance; scratches develop more readily on lenses received with surface irregularities; wettability does not correlate with the extent of surface scratching; recommended cleaning procedures do not directly alter the wettability of the contact lens material; and phase contrast microscopy may be a useful addition to laboratory quality control.

  8. Long-term high-fat diet induces pancreatic injuries via pancreatic microcirculatory disturbances and oxidative stress in rats with hyperlipidemia

    International Nuclear Information System (INIS)

    Yan Mingxian; Li Yanqing; Meng Min; Ren Hongbo; Kou Yi

    2006-01-01

    Relations between hyperlipidemia and chronic pancreatitis remain unclear. Microcirculatory disturbances and oxidative stress are involved in pathogeneses of a high numbers of diseases. The objective of this study was to induce hyperlipidemia in rats by long-term high-fat diet intake, then investigate the biochemical, microcirculatory, and histological alterations in blood and pancreatic tissues of these animals, and discuss their potential significances. Pancreatic blood flow was detected by intravital microscope; malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were measured in pancreatic tissues for assessment of oxidative stress and α-smooth muscle actin (α-SMA) expression was determined by immunohistochemical staining and RT-PCR. The results showed that the velocity of pancreatic microvascular blood flow of rats with hyperlipidemia decreased significantly as compared to control value (p = 0.008). Pancreatic MDA content increased whereas SOD activity decreased in these rats (p = 0.022; p = 0.039, respectively). Histologically, microvesicles in acinar and islet cells, dilated rough endoplasmic reticulum, swollen mitochondrion and modified vascular endothelial cells were observed under light microscope and transmission electron microscope. In addition, α-SMA expression was up-regulated significantly (p < 0.05). These results suggest that long-term high-fat diet can induce chronic pancreatic injuries which could be considered as 'nonalcoholic fatty pancreatic disease', and pancreatic microcirculatory disturbances and oxidative stress may play an important part in the underlying pathogenesis

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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)

  14. 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...

  15. The correct lens mount lightweighting design of thermal cycle stress in Cassegrain telescope

    Science.gov (United States)

    Hsu, M. Y.; Chang, S. T.; Huang, T. M.; Hsu, Ming-Ying

    2011-10-01

    The Cassegrain telescope system was design for space environment. The correct lens mount assembly is included as correct lens, lens mount, spacer, mount barrel and retainer. The system mass budget allocated to correct lens assembly was 5 Kg. Meanwhile, according to optical design the correct lens is made from fused silica, the lens diameter is 130 mm, and the mass is 2.3 Kg. Therefore, remain mass budget is 2.7 Kg; including the lens mount, spacer, mount barrel and retainer. The telescope system deformation is mainly caused by thermal deformation on space orbit. The correct lens mount was made from invar material in initial design. The CTE (Coefficient of Thermal Expansion) of invar is only 1* 10-6/°C, low CTE would be resistant to thermal deformation, but invar density is 8* 10-6 kg/mm3. If all components were made from invar, the total mass was over 2.7 kg. Thus, the components material would consider titanium alloy (CTE is 8.6* 10-6/°C, density is 4.43* 10-6 kg/mm3) or aluminum alloy (CTE is 23.6* 10-6/°C, density is 2.81* 10-6 kg/mm3). The titanium alloy density is 1.83 times lighter than invar, but CTE is 8.6 times higher. The aluminum alloy density is 2.84 times lighter then invar, but CTE is 23.6 times higher. The lens mount thermal deformation would effect correct lens surface wavefront error and introduce optical aberration. This article analyzes the correct lens assembly thermal deformation and optical performance in different lens mount material. From above conditions, using FEM (Finite Element Method) and optical software, simulation and optimization on the lens mount design have been performed to achieve system mass requirement.

  16. 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.

  17. 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

  18. 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

  19. 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

  20. Association of impaired endothelial glycocalyx with arterial stiffness, coronary microcirculatory dysfunction, and abnormal myocardial deformation in untreated hypertensives.

    Science.gov (United States)

    Ikonomidis, Ignatios; Voumvourakis, Astrinos; Makavos, George; Triantafyllidi, Helen; Pavlidis, George; Katogiannis, Konstantinos; Benas, Dimitris; Vlastos, Dimitris; Trivilou, Paraskevi; Varoudi, Maria; Parissis, John; Iliodromitis, Efstathios; Lekakis, John

    2018-03-02

    We investigated the association of endothelial glycocalyx damage with arterial stiffness, impairment of coronary microcirculatory function, and LV myocardial deformation in 320 untreated hypertensives and 160 controls. We measured perfused boundary region (PBR) of the sublingual microvessels, a marker inversely related with glycocalyx thickness, coronary flow reserve (CFR), and Global Longitudinal strain (GLS) by echocardiography, pulse wave velocity (PWV), and central systolic blood pressure (cSBP). Hypertensives had higher PBR, PWV cSBP, and lower CFR and GLS than controls (P < .05). In hypertensives, increased PBR was associated with increased cSBP, PWV, and decreased CFR and GLS after adjustment for age, sex, BMI, smoking LV mass, heart rate, hyperlipidemia, and office SBP (P < .05). PBR had an additive value to PWV, CFR, and office SBP for the prediction of abnormal GLS (x 2  = 2.4-3.8, P for change = .03). Endothelial glycocalyx is impaired in untreated hypertensives and is related to arterial stiffness, coronary, and myocardial dysfunction. ©2018 Wiley Periodicals, Inc.

  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. 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.

  3. 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.

  4. 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.

  5. 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...

  6. Gabor lens theory

    International Nuclear Information System (INIS)

    Irani, A.A.

    1978-01-01

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

  7. Reduction of the divergence angle of an incident beam to enhance the demagnification factor of a two-stage acceleration lens in a gas ion nanobeam system of several tens of keV

    Science.gov (United States)

    Ishii, Yasuyuki; Kojima, Takuji

    2018-04-01

    The demagnification factor of a two-stage acceleration lens in a gas ion nanobeam system that produces ion beams with energies in the order of 10 keV was enhanced in this study so that a hydrogen ion beam with a diameter of 115 nm could be produced. The reduction of the divergence angle of the incident beam into the two-stage acceleration lens is the effective method for enhancing the demagnification factor. The divergence angle has been gradually reduced by firstly introducing the preacceleration electrodes to control the divergence angle, namely divergence-angle-control electrodes, and secondly replacing an anode with a modified anode that possesses a Pierce electrode, both of which were in an ion source directly connected to the lens. In this study, the divergence angle of less than 3.6 × 10-4 rad that was previously used to produce a 160-nm hydrogen ion beam with the energy of 46 keV by the above procedure was numerically determined using an ion beam extraction simulation code. The determined minimum divergence angle of the incident ion beam was calculated to be 2.0 × 10-4 rad, which was about half of the previously obtained divergence angle; this was used to experimentally form a hydrogen beam with a diameter of 115 ± 10 nm and the energy of 47 keV. The demagnification factor was estimated to be 1,739 using the newly formed hydrogen beam, which was similar to the simulation result.

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

    Science.gov (United States)

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

    2007-12-01

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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. TECA (Titrated Extract of Centella Asiatica): new microcirculatory, biomolecular, and vascular application in preventive and clinical medicine. A status paper.

    Science.gov (United States)

    Belcaro, G; Maquart, F-X; Scoccianti, M; Dugall, M; Hosoi, M; Cesarone, M R; Luzzi, R; Cornelli, U; Ledda, A; Feragalli, B

    2011-09-01

    Plant-derived elements used for pharmacological applications constitute an increasing research field. Centella asiatica is widely used mainly as an extract (TECA). Triterpenic fractions, the primary constituents of Centella asiatica, produce a wide range of preventive and therapeutic effects. The modulation of collagen production and deposition in wound healing is of primary importance. TECA is also used to treat several microcirculatory problems, inflammatory skin conditions (leprosy, lupus, varicose ulcers, eczema, atopic dermatitis, psoriasis) and also intestinal problems, fever, amenorrhea and genitourinary conditions. Cognitive functions, anxiety and mental impairment may be also affected by TECA administration. New applications in neurology include nerve growth factor enhancement and applications in neurological degenerative conditions. Interaction with other products is also indicated in this document. The multiplicity of actions of TECA is associated to six important mechanisms, all inter-connected and modulating each other: 1) edema - and capillary filtration - control; 2) a strong antioxidant power, effective on several forms of oxidative stress associated to inflammation or infections and synergic with other antioxidant products; 3) an anti-inflammatory action; 4) a modulation of the collagen production avoiding slower scarring or faster, hyperthrophic scarring and cheloids; 5) a modulating action of local growth factors; 6) a modulation of angiogenesis. This "status" paper - resulting from an expert meeting held in Cobham, Surrey, indicates most of the therapeutic potential of TECA, still to be explored in further studies. The status paper constitutes the basis for a consensus document on TECA to be developed in the next future. This "status" paper opens a new window on an ancient but still partially unexplored product that may become an important value in prevention and treatment of several pre-clinical and risk conditions and in clinically significant

  14. Determination of optical parameters of a GRIN lens by intercept measurement

    Science.gov (United States)

    Zhang, Yufei; Xiong, Baoxing; Xu, Qinfeng; Guo, Changwei; Zhang, Guiju; Xu, Feng; Zou, Kuaisheng

    2018-03-01

    An experimental method is used to measure the optical parameters of a GRIN lens. The intrinsic properties of the lens are well characterized by measuring the intercept values of the different GRIN lenses. Firstly, the intercept equation is derived from the transmission matrix of the GRIN lens, and the measurement method is described in detail. Secondly, we design and make the optical path measuring system. Finally, the error analysis of the experimental results is presented, which shows the feasibility of the working principle and the experiment operation. The principle and equipment of this measuring method are relatively effective, which affords great practical significance for the measurement of the GRIN lens.

  15. [Current quality management situation and administration countermeasure study of enterprises marketing corneal contact lens].

    Science.gov (United States)

    Liu, Yungui; Yao, Ying; Shangguan, Shihao; Gu, Qun; Gao, Wuming; Chen, Yaoshui

    2014-05-01

    Study the current quality management situation of enterprises marketing corneal contact lens via systemic investigations and explore effective administration countermeasures in the future. The quality management indicators of sixty-two corneal contact lens marketing enterprises in Xuhui district of Shanghai were systematically investigated and enterprises of different operation models was compared and analyzed. Wholesale enterprises and retail chain enterprises are apparently better than independent enterprises almost in all facets. Facilitate market accession of corneal contact lens marketing enterprises, encourage the business model of retail chain, enhance supervision of corneal contact lens marketing enterprises, especially independent franchisors.

  16. 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.

  17. 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.

  18. A framework of cloud supported collaborative design in glass lens moulds based on aspheric measurement

    Science.gov (United States)

    Zhu, Yongjian; Wang, Yu; Na, Jingxin; Zhi, Yanan; Fan, Yufeng

    2013-09-01

    Aspheric mould design includes the top-down design and reversal design. In this paper, a new framework of reversal design is proposed combining with cloud supported collaborative design (CSCD) based on aspheric measurement. The framework is a kind of collaborative platform, which is composed of eight modules, including the computerized aspheric precision measurement module (CAPM), computer-aided optical design of aspheric lens system (CAOD), computer-aided design of lens mould (CADLM), FEM(finite element method) simulation of lens molding module (FEMLM), computer-aided manufacture of lens and moulds (CAMLM), measurement data analysis module (MDAM), optical product lifecycle management module (OPLM) and cloud computing network module (CCNM). In this framework, the remote clients send an improved requirement or fabrication demand about optical lens system through CCNM, which transfers this signal to OPLM. In OPLM, one main server is in charge of the task distribution and collaborative work of other six modules. The first measurement data of aspheric lens are produced by clients or our proposed platform CAPM, then are sent to CAOD for optimization and the electronic drawings of lens moulds are generated in CADLM module. According the design drawings, the FEMLM could give the lens-molding simulation parameters through FEM software. The simulation data are used for the second design of moulds in CADLM module. In this case, the moulds could be fabricated in CAMLM by ultra-precision machine, and the aspheric lens could be also produced by lens-molding machine in CAMLM. At last, the final shape of aspheric lens could be measured in CAPM and the data analysis could be conducted in MDAM module. Through the proposed framework, all the work described above could be performed coordinately. And the optimum design data of lens mould could be realized and saved, then shared by all the work team.

  19. Dissecting the Gravitational lens B1608+656 : II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State

    NARCIS (Netherlands)

    Suyu, S. H.; Marshall, P. J.; Auger, M. W.; Hilbert, S.; Blandford, R. D.; Koopmans, L. V. E.; Fassnacht, C. D.; Treu, T.

    2010-01-01

    Strong gravitational lens systems with measured time delays between the multiple images provide a method for measuring the "time-delay distance" to the lens, and thus the Hubble constant. We present a Bayesian analysis of the strong gravitational lens system B1608+656, incorporating (1) new, deep

  20. 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.

  1. 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.

  2. Quantitative Analysis of Lens Nuclear Density Using Optical Coherence Tomography (OCT with a Liquid Optics Interface: Correlation between OCT Images and LOCS III Grading

    Directory of Open Access Journals (Sweden)

    You Na Kim

    2016-01-01

    Full Text Available Purpose. To quantify whole lens and nuclear lens densities using anterior-segment optical coherence tomography (OCT with a liquid optics interface and evaluate their correlation with Lens Opacities Classification System III (LOCS III lens grading and corrected distance visual acuity (BCVA. Methods. OCT images of the whole lens and lens nucleus of eyes with age-related nuclear cataract were analyzed using ImageJ software. The lens grade and nuclear density were represented in pixel intensity units (PIU and correlations between PIU, BCVA, and LOCS III were assessed. Results. Forty-seven eyes were analyzed. The mean whole lens and lens nuclear densities were 26.99 ± 5.23 and 19.43 ± 6.15 PIU, respectively. A positive linear correlation was observed between lens opacities (R2 = 0.187, p<0.01 and nuclear density (R2 = 0.316, p<0.01 obtained from OCT images and LOCS III. Preoperative BCVA and LOCS III were also positively correlated (R2 = 0.454, p<0.01. Conclusions. Whole lens and lens nuclear densities obtained from OCT correlated with LOCS III. Nuclear density showed a higher positive correlation with LOCS III than whole lens density. OCT with a liquid optics interface is a potential quantitative method for lens grading and can aid in monitoring and managing age-related cataracts.

  3. [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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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...

  9. 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

  10. 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.

  11. Review of the Experimental Background and Implementation of Computational Models of the Ocular Lens Microcirculation.

    Science.gov (United States)

    Wu, Ho-Ting D; Donaldson, Paul J; Vaghefi, Ehsan

    2016-01-01

    Our sense of vision is critically dependent on the clarity of the crystalline lens. The most common cause of transparency loss in the lens is age-related nuclear cataract, which is due to accumulative oxidative damage to this tissue. Since the ocular lens is an avascular tissue, it has to maintain its physiological homeostasis and antioxidant levels using a system of water microcirculation. This system has been experimentally imaged in animal lenses using different modalities. Based on these data, computational models have been developed to predict the properties of this system in human lenses and its changes due to aging. Although successful in predicting many aspects of lens fluid dynamics, at least in animal models, these in-silica models still need further improvement to become more accurate and representative of human ocular lens. We have been working on gathering experimental data and simultaneously developing computational models of lens microcirculation for the past decade. This review chronologically looks at the development of data-driven computational foundations of lens microcirculation model, its current state, and future advancement directions. A comprehensive model of lens fluid dynamics is essential to understand the physiological optics of this tissue and ultimately the underlying mechanisms of cataract onset and progression.

  12. Electrowetting liquid lens array on curved substrates for wide field of view image sensor

    Science.gov (United States)

    Bang, Yousung; Lee, Muyoung; Won, Yong Hyub

    2016-03-01

    In this research, electrowetting liquid lens array on curved substrates is developed for wide field of view image sensor. In the conventional image sensing system, this lens array is usually in the form of solid state. However, in this state, the lens array which is similar to insect-like compound eyes in nature has several limitations such as degradation of image quality and narrow field of view because it cannot adjust focal length of lens. For implementation of the more enhanced system, the curved array of lenses based on electrowetting effect is developed in this paper, which can adjust focal length of lens. The fabrication of curved lens array is conducted upon the several steps, including chamber fabrication, electrode & dielectric layer deposition, liquid injection, and encapsulation. As constituent materials, IZO coated convex glass, UV epoxy (NOA 68), DI water, and dodecane are used. The number of lenses on the fabricated panel is 23 by 23 and each lens has 1mm aperture with 1.6mm pitch between adjacent lenses. When the voltage is applied on the device, it is observed that each lens is changed from concave state to convex state. From the unique optical characteristics of curved array of liquid lenses such as controllable focal length and wide field of view, we can expect that it has potential applications in various fields such as medical diagnostics, surveillance systems, and light field photography.

  13. 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.

  14. Ameliorating effects of traditional Chinese medicine on lipopolysaccharide -induced microcirculatory disturbances and organ injury.

    Science.gov (United States)

    Sun, Kai; Pan, Chun-Sui; Li, Quan; Furukawa, Osamu; Fan, Jing-Yu; Han, Jing-Yan

    2015-03-16

    Gram-negative bacteria are one of the major pathogens associated with severe sepsis and septic shock. LPS is a component of the outer membrane of gram-negative bacteria, which causes a systemic, uncontrolled inflammatory response in infected subjects. In microcirculation it manifests multiple insults, including leukocyte and platelet adhesion, ROS and protease overproduction, mast cell degranulation, endothelium hyperpermeabilty, hemorrhage, and microthrombi formation, ultimately results in multiorgan dysfunction, DIC, refractory shock and even death. TCM has been used in China, Korea, Japan and other Asian countries for treatment of a wide range of diseases. In China, the usage of compound traditional preparation to treat inflammation-related diseases dates back to the Han Dynasty and the medical formulary had been developed thousands of years before, which recorded a great number of classical prescriptions for treatment with infectious diseases. This review will summarize the up to date works with respect to the ameliorating effects of compound and single traditional Chinese medicine and active components on LPS-induced inflammation, including clinical trial and experimental studies regarding multiorgan injury and underlying mechanisms.

  15. Development of a 3D finite element model of lens microcirculation

    Directory of Open Access Journals (Sweden)

    Vaghefi Ehsan

    2012-09-01

    Full Text Available Abstract Background It has been proposed that in the absence of a blood supply, the ocular lens operates an internal microcirculation system. This system delivers nutrients, removes waste products and maintains ionic homeostasis in the lens. The microcirculation is generated by spatial differences in membrane transport properties; and previously has been modelled by an equivalent electrical circuit and solved analytically. While effective, this approach did not fully account for all the anatomical and functional complexities of the lens. To encapsulate these complexities we have created a 3D finite element computer model of the lens. Methods Initially, we created an anatomically-correct representative mesh of the lens. We then implemented the Stokes and advective Nernst-Plank equations, in order to model the water and ion fluxes respectively. Next we complemented the model with experimentally-measured surface ionic concentrations as boundary conditions and solved it. Results Our model calculated the standing ionic concentrations and electrical potential gradients in the lens. Furthermore, it generated vector maps of intra- and extracellular space ion and water fluxes that are proposed to circulate throughout the lens. These fields have only been measured on the surface of the lens and our calculations are the first 3D representation of their direction and magnitude in the lens. Conclusion Values for steady state standing fields for concentration and electrical potential plus ionic and fluid fluxes calculated by our model exhibited broad agreement with observed experimental values. Our model of lens function represents a platform to integrate new experimental data as they emerge and assist us to understand how the integrated structure and function of the lens contributes to the maintenance of its transparency.

  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. 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

  18. 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

  19. Statins prevent cognitive impairment after sepsis by reverting neuroinflammation, and microcirculatory/endothelial dysfunction.

    Science.gov (United States)

    Reis, Patricia A; Alexandre, Pedro C B; D'Avila, Joana C; Siqueira, Luciana D; Antunes, Barbara; Estato, Vanessa; Tibiriça, Eduardo V; Verdonk, Franck; Sharshar, Tarek; Chrétien, Fabrice; Castro-Faria-Neto, Hugo C; Bozza, Fernando A

    2017-02-01

    Acute brain dysfunction is a frequent condition in sepsis patients and is associated with increased mortality and long-term neurocognitive consequences. Impaired memory and executive function are common findings in sepsis survivors. Although neuroinflammation and blood-brain barrier dysfunction have been associated with acute brain dysfunction and its consequences, no specific treatments are available that prevent cognitive impairment after sepsis. Experimental sepsis was induced in Swiss Webster mice by intraperitoneal injection of cecal material (5mg/kg, 500μL). Control groups (n=5/group each experiment) received 500μL of saline. Support therapy recover (saline 0.9%, 1mL and imipenem 30mg/kg) were applied (6, 24 and 48h post injection, n=5-10/group, each experiment), together or not with additive orally treatment with statins (atorvastatin/simvastatin 20mg/kg b.w.). Survival rate was monitored at 6, 24 and 48h. In a setting of experiments, animals were euthanized at 6 and 24h after induction for biochemical, immunohistochemistry and intravital analysis. Statins did not prevented mortality in septic mice, however survivors presented lower clinical score. At another setting of experiments, after 15days, mice survivors from fecal supernatant peritoneal sepsis presented cognitive dysfunction for contextual hippocampal and aversive amygdala-dependent memories, which was prevented by atorvastatin/simvastatin treatment. Systemic and brain tissue levels of proinflammatory cytokines/chemokines and activation of microglial were lower in septic mice treated with statins. Brain lipid peroxidation and myeloperoxidase levels were also reduced by statins treatment. Intravital examination of the brain vessels of septic animals revealed decreased functional capillary density and increased rolling and adhesion of leukocytes, and blood flow impairment, which were reversed by treatment with statins. In addition, treatment with statins restored the cholinergic vasodilator response

  20. 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.

  1. Laser Tweezer Controlled Solid Immersion Lens for High Resolution Imaging in Microfluidic and Biological Samples

    National Research Council Canada - National Science Library

    Birkbeck, Aaron L; Zlatanovic, Sanja; Ozkan, Mihrimah; Esener, Sadik C

    2005-01-01

    ...). Up to now, solid immersion lens imaging systems have relied upon cantilever-mounted SILs that are difficult to integrate into microfluidic systems and require an extra alignment step with external optics...

  2. 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.

  3. Qualification of a Null Lens Using Image-Based Phase Retrieval

    Science.gov (United States)

    Bolcar, Matthew R.; Aronstein, David L.; Hill, Peter C.; Smith, J. Scott; Zielinski, Thomas P.

    2012-01-01

    In measuring the figure error of an aspheric optic using a null lens, the wavefront contribution from the null lens must be independently and accurately characterized in order to isolate the optical performance of the aspheric optic alone. Various techniques can be used to characterize such a null lens, including interferometry, profilometry and image-based methods. Only image-based methods, such as phase retrieval, can measure the null-lens wavefront in situ - in single-pass, and at the same conjugates and in the same alignment state in which the null lens will ultimately be used - with no additional optical components. Due to the intended purpose of a Dull lens (e.g., to null a large aspheric wavefront with a near-equal-but-opposite spherical wavefront), characterizing a null-lens wavefront presents several challenges to image-based phase retrieval: Large wavefront slopes and high-dynamic-range data decrease the capture range of phase-retrieval algorithms, increase the requirements on the fidelity of the forward model of the optical system, and make it difficult to extract diagnostic information (e.g., the system F/#) from the image data. In this paper, we present a study of these effects on phase-retrieval algorithms in the context of a null lens used in component development for the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Approaches for mitigation are also discussed.

  4. A theoretical lens for revealing the complexity of chronic care

    NARCIS (Netherlands)

    Borgermans, L.; de Maeseneer, J.; Wollersheim, H.; Vrijhoef, H.J.M.; Devroey, D.

    2013-01-01

    The increasing prevalence of co-occurring multiple chronic conditions in an aging population has influenced the debate on complexity in chronic care and nowadays provides an impetus to the reform of numerous health systems. This article presents a theoretical lens for understanding the complexity of

  5. Forgotten Forests? Food Potential of Ancient Coffee Forests and Agroforestry Systems in the Southwestern Ethiopian Mountains, Seen Through a Gender Lens

    Directory of Open Access Journals (Sweden)

    Sarah Marie Nischalke

    2017-08-01

    Full Text Available Forests play an important role in the provision of food and livelihoods across the globe. Thus, forest protection contributes to a diverse set of Sustainable Development Goals. The Yayu Coffee Forest Biosphere Reserve in the southwestern Ethiopian mountains (elevation 1100–2300 m above sea level hosts an ancient coffee forest with high biodiversity and a large nutritional potential. It is managed in zones, and smallholder farmers can still use forest resources in the buffer and transitional zones in a sustainable manner. The forest is rarely used as a food source, although a large majority of the population in this area suffers from micronutrient deficiencies. This article investigates whether sustainable use of forest resources can contribute to the achievement of different Sustainable Development Goals by looking, through a gender lens, at which forest ecosystem services the community uses; traditional coffee farmers' perceptions of wild edible plants, agricultural territories, and labor divisions; and the constraining factors for forest conservation and sustainable agroforestry on private forest plots. Data for this study were collected through ethnography, transect walks, a sex-disaggregated household survey (n = 334, 32 semistructured interviews, 40 focus groups, and 13 key stakeholder interviews. One reason for neglecting the forest as a food source is that forests are considered a male territory, while vegetable raising and nutrition are female responsibilities. In addition, the collection of wild foods is perceived as a last resort during a famine and as a practice of tribal groups. Because coffee production represents the traditional livelihood source, farmers accept the need to conserve the forest, which is necessary to achieve the Sustainable Development Goals. While it may have negative implications for food security, the absence of a tradition of collecting wild plants is positive news for forest conservation.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Early microcirculatory impairment during therapeutic hypothermia is associated with poor outcome in post-cardiac arrest children: a prospective observational cohort study.

    Science.gov (United States)

    Buijs, Erik A B; Verboom, Elyse M; Top, Anke P C; Andrinopoulou, Eleni-Rosalina; Buysse, Corinne M P; Ince, Can; Tibboel, Dick

    2014-03-01

    This study aimed to evaluate if the microcirculation is impaired during and after therapeutic hypothermia (TH) in children with return of spontaneous circulation after cardiac arrest (CA) and to assess if microcirculatory impairment predicts mortality. This has been reported for post-CA adults, but results might be different for children because etiology, pathophysiology, and mortality rate differ. This prospective observational cohort study included consecutive, non-neonatal post-CA children receiving TH upon intensive care admission between June 2008 and June 2012. Also included were gender-matched and age-matched normothermic, control children without cardiorespiratory disease. The buccal microcirculation was non-invasively assessed with Sidestream Dark Field Imaging at the start of TH, halfway during TH, at the start of re-warming, and at normothermia. Macrocirculatory, respiratory, and biochemical parameters were also collected. Twenty post-CA children were included of whom 9 died. During hypothermia, the microcirculation was impaired in the post-CA patients and did not change over time. At normothermia, the core body temperature and the microcirculation had increased and no longer differed from the controls. Microcirculatory deterioration was associated with mortality in the post-CA patients. In particular, the microcirculation was more severely impaired at TH start in the non-survivors than in the survivors - positive predictive value: 73-83, negative predictive value: 75-100, sensitivity: 63-100%, and specificity: 70-90%. The microcirculation is impaired in post-CA children during TH and more severe impairment at TH start was associated with mortality. After the stop of TH, the microcirculation improves rapidly irrespective of outcome. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Zhang, D.

    2015-01-01

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  16. 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

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    awareness can lead to avoidance or even prevention. Learning Objectives: To understand recent changes in eye lens dose limits and thresholds for tissue reactions To understand different approaches to dose estimation for eye lens To learn about challenges in eye lens opacities among staff in interventional fluoroscopy Di Zhang, Toshiba America Medical Systems, Tustin, CA, USA Eye lens radiation dose from brain perfusion CT exams CT perfusion imaging requires repeatedly exposing one location of the head to monitor the uptake and washout of iodinated contrast. The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. CTDIvol assumes continuous z coverage and can overestimate eye lens dose in CT perfusion scans where the table do not increment. The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. MDCT scanners from four major manufacturers were simulated and the eye lens doses were estimated using the AAPM posted clinical protocols. They were also compared to CTDIvol values to evaluate the overestimation from CTDIvol. The efficacy of eye lens dose reduction techniques such as tilting the gantry and moving the scan location away from the eyelens were also investigated. Eye lens dose ranged from 81 mGy to 279 mGy, depending on the scanner and protocol used. It is between 59% and 63% of the CTDIvol values reported by the scanners. The eye lens dose is significantly reduced when the eye lenses were not directly irradiated. CTDIvol should not be interpreted as patient dose; this study has shown it to overestimate dose to the eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice

  18. 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.

  19. 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.

  20. 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.

  1. The Time Lens Concept Applied to Ultra-High-Speed OTDM Signal Processing

    DEFF Research Database (Denmark)

    Clausen, Anders; Palushani, Evarist; Mulvad, Hans Christian Hansen

    2013-01-01

    This survey paper presents some of the applications where the versatile time-lens concept successfully can be applied to ultra-high-speed serial systems by offering expected needed functionalities for future optical communication networks....

  2. Direct Multipixel Imaging and Spectroscopy of an exoplanet with a Solar Gravity Lens Mission

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to study a mission to the deep regions outside the solar system that will exploit the remarkable optical properties of the Solar Gravitational Lens (SGL)...

  3. 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.

  4. Eye lens membrane junctional microdomains: a comparison between healthy and pathological cases

    Energy Technology Data Exchange (ETDEWEB)

    Buzhynskyy, Nikolay; Scheuring, Simon [Institut Curie, Equipe Inserm Avenir, UMR168-CNRS, 26 Rue d' Ulm, 75248 Paris Cedex 05 (France); Sens, Pierre [ESPCI, CNRS-UMR 7083, 75231 Paris (France); Behar-Cohen, Francine, E-mail: simon.scheuring@curie.fr [UMRS Inserm 872, Universite Paris Descartes, Centre de Recherches des Cordeliers, 15 rue de l' Ecole de Medecine, 75270 Paris Cedex 06 (France)

    2011-08-15

    The eye lens is a transparent tissue constituted of tightly packed fiber cells. To maintain homeostasis and transparency of the lens, the circulation of water, ions and metabolites is required. Junctional microdomains connect the lens cells and ensure both tight cell-to-cell adhesion and intercellular flow of fluids through a microcirculation system. Here, we overview membrane morphology and tissue functional requirements of the mammalian lens. Atomic force microscopy (AFM) has opened up the possibility of visualizing the junctional microdomains at unprecedented submolecular resolution, revealing the supramolecular assembly of lens-specific aquaporin-0 (AQP0) and connexins (Cx). We compare the membrane protein assembly in healthy lenses with senile and diabetes-II cataract cases and novel data of the lens membranes from a congenital cataract. In the healthy case, AQP0s form characteristic square arrays confined by connexons. In the cases of senile and diabetes-II cataract patients, connexons were degraded, leading to malformation of AQP0 arrays and breakdown of the microcirculation system. In the congenital cataract, connexons are present, indicating probable non-membranous grounds for lens opacification. Further, we discuss the energetic aspects of the membrane organization in junctional microdomains. The AFM hence becomes a biomedical nano-imaging tool for the analysis of single-membrane protein supramolecular association in healthy and pathological membranes.

  5. Eye lens membrane junctional microdomains: a comparison between healthy and pathological cases

    Science.gov (United States)

    Buzhynskyy, Nikolay; Sens, Pierre; Behar-Cohen, Francine; Scheuring, Simon

    2011-08-01

    The eye lens is a transparent tissue constituted of tightly packed fiber cells. To maintain homeostasis and transparency of the lens, the circulation of water, ions and metabolites is required. Junctional microdomains connect the lens cells and ensure both tight cell-to-cell adhesion and intercellular flow of fluids through a microcirculation system. Here, we overview membrane morphology and tissue functional requirements of the mammalian lens. Atomic force microscopy (AFM) has opened up the possibility of visualizing the junctional microdomains at unprecedented submolecular resolution, revealing the supramolecular assembly of lens-specific aquaporin-0 (AQP0) and connexins (Cx). We compare the membrane protein assembly in healthy lenses with senile and diabetes-II cataract cases and novel data of the lens membranes from a congenital cataract. In the healthy case, AQP0s form characteristic square arrays confined by connexons. In the cases of senile and diabetes-II cataract patients, connexons were degraded, leading to malformation of AQP0 arrays and breakdown of the microcirculation system. In the congenital cataract, connexons are present, indicating probable non-membranous grounds for lens opacification. Further, we discuss the energetic aspects of the membrane organization in junctional microdomains. The AFM hence becomes a biomedical nano-imaging tool for the analysis of single-membrane protein supramolecular association in healthy and pathological membranes.

  6. 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

  7. [Advantage of higher oxygen transmissibility material Piggyback lens for keratoconus correction].

    Science.gov (United States)

    Xie, Pei-Ying; Chi, Hui; Yang, Li-Na

    2011-01-01

    To evaluate the oxygen transmissibility of new material Piggyback lens combined with silicone hydrogel lens and higher Dk RGPCL. To investigate the improving of visual acuity, ocular shape and comfortable, also orthokeratology results and safety of this new system for keratoconus correction. Calculating the oxygen transmission (Dk/t) of the new Piggyback system involves Ohm's Law. Compare the changes of ocular surface curves and astigmatism with or without Si-SCL fitting, RGPCL vision and Piggyback lens vision. Investigate the comfortable improving and ocular complications, and changes of corneal shape after fitted with Piggyback lens by using corneal topography. Selected silicone hydrogel lens was pure vision (B&L PV, 36% water, Dk/t 110) lens, RGPCL material was Menicon Z, Dk/t 95.9 and Boston XO, Dk/t 58.8. It was calculated to 44.4 Dk/t and 34.4 Dk/t with these two combinations. Twenty two moderate and severe keratoconus patients (28 eyes) fitted with the Piggyback lens successfully. Corneal K reading and astigmatism decreased significantly after wore the Si-SCL. Compared with RGPCL vision(4.82 ± 0.11), Piggyback lens vision (4.93 ± 0.08) was significant increased (t = -10.395, P < 0.01) 90% cases improved comfort vs prior RGPCL wear alone. Only few cases appeared slight conjunctival hyperemia and corneal staining. Corneal topography showed corneal flatter, spherical and regular reshaping results after 6 months wore the Piggyback lens. By fitting Piggyback systems using new Si-SCL and higher Dk RGPCL materials may help problematic keratoconic patients improve visual acuity, comfort and safety, increase wearing time and orthokeratology results further.

  8. Non-contact optical measurement of lens capsule thickness during simulated accommodation

    Science.gov (United States)

    Ziebarth, Noel; Manns, Fabrice; Acosta, Ana-Carolina; Parel, Jean-Marie

    2005-04-01

    Purpose: To non-invasively measure the thickness of the anterior and posterior lens capsule, and to determine if it significantly changes during accommodation. Methods: Anterior and posterior capsule thickness was measured on post-mortem lenses using a non-contact optical system using a focus-detection technique. The optical system uses a 670nm laser beam delivered to a single-mode fiber coupler. The output of the fiber coupler is focused on the tissue surface using an aspheric lens (NA=0.68) mounted on a translation stage with a motorized actuator. Light reflected from the sample surface is collected by the fiber coupler and sent to a photoreceiver connected to a computer-controlled data acquisition system. Optical intensity peaks are detected when the aspheric lens is focused on the capsule boundaries. The capsule thickness is equal to the distance traveled between two peaks multiplied by the capsule refractive index. Anterior and posterior lens capsule thickness measurements were performed on 18 cynomolgus (age average: 6+/-1 years, range: 4-7 years) eyes, 1 rhesus (age: 2 years) eye, and 12 human (age average: 65+/-16, range: 47-92) eyes during simulated accommodation. The mounted sample was placed under the focusing objective of the optical system so that the light was incident on the center pole. Measurements were taken of the anterior lens capsule in the unstretched and the stretched 5mm states. The lens was flipped, and the same procedure was performed for the posterior lens capsule. Results: The precision of the optical system was determined to be +/-0.5um. The resolution is 4um and the sensitivity is 52dB. The human anterior lens capsule thickness was 6.0+/-1.2um unstretched and 4.9+/-0.9um stretched (p=0.008). The human posterior lens capsule was 5.7+/-1.2um unstretched and 5.7+/-1.4um stretched (p=0.974). The monkey anterior lens capsule thickness was 5.9+/-1.9um unstretched and 4.8+/-1.0um stretched (p=0.002). The monkey posterior lens capsule was 5

  9. 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.

  10. 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.)

  11. Eyeglasses Lens Contour Extraction from Facial Images Using an Efficient Shape Description

    Directory of Open Access Journals (Sweden)

    Diana Borza

    2013-10-01

    Full Text Available This paper presents a system that automatically extracts the position of the eyeglasses and the accurate shape and size of the frame lenses in facial images. The novelty brought by this paper consists in three key contributions. The first one is an original model for representing the shape of the eyeglasses lens, using Fourier descriptors. The second one is a method for generating the search space starting from a finite, relatively small number of representative lens shapes based on Fourier morphing. Finally, we propose an accurate lens contour extraction algorithm using a multi-stage Monte Carlo sampling technique. Multiple experiments demonstrate the effectiveness of our approach.

  12. Developing students’ ideas about lens imaging: teaching experiments with an image-based approach

    Science.gov (United States)

    Grusche, Sascha

    2017-07-01

    Lens imaging is a classic topic in physics education. To guide students from their holistic viewpoint to the scientists’ analytic viewpoint, an image-based approach to lens imaging has recently been proposed. To study the effect of the image-based approach on undergraduate students’ ideas, teaching experiments are performed and evaluated using qualitative content analysis. Some of the students’ ideas have not been reported before, namely those related to blurry lens images, and those developed by the proposed teaching approach. To describe learning pathways systematically, a conception-versus-time coordinate system is introduced, specifying how teaching actions help students advance toward a scientific understanding.

  13. 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)

  14. 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.

  15. 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.

  16. 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...

  17. [Contact lens related corneal ulcers: clinical, microbiological and therapeutic features].

    Science.gov (United States)

    Benhmidoune, L; Bensemlali, A; Bouazza, M; Karami, R; El Mansouri, H; El Belhadji, M; Rachid, R; Chakib, A; Amraoui, A

    2013-09-01

    Corneal ulcers in contact lens wearers are becoming more common, and can sometimes lead to severe complications. The purpose of this study is to define the epidemiological, clinical, microbiological and therapeutic considerations of these ulcers within the above context. We conducted an uncontrolled, descriptive, retrospective study of 51 patients presenting with contact lens related corneal ulcers to the ophthalmology department of the August 20, 1953 Hospital in Casablanca between January 2009 and January 2012. The average age of our patients was 22 years, with a gender ratio of 7.5 female to male. General risk factors (diabetes and tuberculosis) were found in 17.5% of cases. The average length of hospital stay was 15 days. Of our patients, 58.8% wore cosmetic contact lenses and 41.18% wore therapeutic contact lenses. Mean duration prior to consultation was 5 days. The predominant clinical signs were eye pain and redness, with a decrease in visual acuity worse than 1/10 in 82.3% of patients. In 70.6% of cases, the ulcer was central. The average size was 4.3mm. An anterior chamber reaction was found in 47.1%. Corneal bacterial cultures were positive in 47.8%. Pathogens found were Staphylococcus aureus, Pseudomonas aeruginosa and Acanthamœba. Contact lens and solution cultures were positive in 73.6% of cases. Outcomes were favorable with local and systemic antibiotic treatment adapted to microbiological results in only 41.2% of cases. In the remaining patients, significant secondary opacities persisted. Cosmetic and therapeutic contact lens wear is a major cause of corneal ulcer. Delayed consultation results in severe sequelae with persistently decreased visual acuity. The ophthalmologist plays an important role in preventing complications of contact lens wear, through better hygiene instruction and follow-up of his or her patients. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  18. The ATI score (age-thrombus burden-index of microcirculatory resistance) determined during primary percutaneous coronary intervention predicts final infarct size in patients with ST-elevation myocardial infarction: a cardiac magnetic resonance validation study.

    Science.gov (United States)

    De Maria, Giovanni Luigi; Alkhalil, Mohammad; Wolfrum, Mathias; Fahrni, Gregor; Borlotti, Alessandra; Gaughran, Lisa; Dawkins, Sam; Langrish, Jeremy P; Lucking, Andrew J; Choudhury, Robin P; Porto, Italo; Crea, Filippo; Dall'Armellina, Erica; Channon, Keith M; Kharbanda, Rajesh K; Banning, Adrian P

    2017-10-20

    The age-thrombus burden-index of microcirculatory resistance (ATI) score is a diagnostic tool able to predict suboptimal myocardial reperfusion before stenting, in patients with ST-elevation myocardial infarction (STEMI). We aimed to validate the ATI score against cardiac magnetic resonance imaging (cMRI). The ATI score was calculated prospectively in 80 STEMI patients. cMRI was performed within 48 hours in all patients and in 50 patients at six-month follow-up to assess the extent of infarct size (IS%) and microvascular obstruction (MVO%). The ATI score was calculated using age (>50=1 point), pre-stenting index of microcirculatory resistance (IMR) (>40 and <100=1 point; ≥100=2 points) and angiographic thrombus score (4=1 point; 5=3 points). ATI score was closely related to final IS% (ATI.

  19. 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.

  20. Temporal properties of the lens eyes of the box jellyfish Tripedalia cystophora

    DEFF Research Database (Denmark)

    O'Connor, Megan; Nilsson, Dan-E; Garm, Anders Lydik

    2010-01-01

    Box jellyWsh (Cubomedusae) are visually orientating animals which posses a total of 24 eyes of 4 morphological types; 2 pigment cup eyes (pit eye and slit eye) and 2 lens eyes [upper lens-eye (ule) and lower lens-eye (lle)]. In this study, we use electroretinograms (ERGs) to explore temporal...... properties of the two lens eyes. We Wnd that the ERG of both lens eyes are complex and using sinusoidal Xicker stimuli we Wnd that both lens eyes have slow temporal resolution. The average Xicker fusion frequency (FFF) was found to be approximately 10 Hz for the ule and 8 Hz for the lle. Di......Verences in the FFF and response patterns between the two lens eyes suggest that the ule and lle Wlter information diVerently in the temporal domain and thus are tuned to perform diVerent visual tasks. The data collected in this study support the idea that the visual system of box jellyWsh is a collection of special...

  1. Focal length measurement of a varifocal liquid lens with capacitance detection

    Science.gov (United States)

    Noda, Kentaro; Binh-Khiem, Nguyen; Takei, Yusuke; Takahata, Tomoyuki; Matsumoto, Kiyoshi; Shimoyama, Isao

    2014-04-01

    This paper reports on a detailed deformation model of varifocal liquid lenses fabricated by Parylene-on-liquid-deposition (POLD), which can be applied to measure and adjust the focal length of such lenses without using extra sensors or sensing mechanisms. The lens was fabricated by encapsulating a liquid between a transparent electrode and a polymer film that was covered with a metal electrode. When voltage is applied to the two electrodes, the lens deforms due to the electrostatic force, and its focal length and the capacitance between the two electrodes change simultaneously. This characteristic enables the focal length of the lens to be adjusted and detected by measuring the capacitance change. The focal length of the fabricated varifocal liquid lens changed from 153.6 to 82.6 mm by applying 150-V. The focal length change of the liquid lens was calculated from the change in its capacitance. Finally, to confirm the efficiency of this varifocal liquid lens, we fabricated a confocal distance sensor using the lens for laser scanning and demonstrated that this system can be used to measure distances of 94-140 mm with an average error of 0.83 mm and a standard deviation of 0.77 mm.

  2. Optomechanical integrated simulation of Mars medium resolution lens with large field of view

    Science.gov (United States)

    Yang, Wenqiang; Xu, Guangzhou; Yang, Jianfeng; Sun, Yi

    2017-10-01

    The lens of Mars detector is exposed to solar radiation and space temperature for long periods of time during orbit, so that the ambient temperature of the optical system is in a dynamic state. The optical and mechanical change caused by heat will lead to camera's visual axis drift and the wavefront distortion. The surface distortion of the optical lens includes the displacement of the rigid body and the distortion of the surface shape. This paper used the calculation method based on the integrated optomechanical analysis, to explore the impact of thermodynamic load on image quality. Through the analysis software, established a simulation model of the lens structure. The shape distribution and the surface characterization parameters of the lens in some temperature ranges were analyzed and compared. the PV / RMS value, deformation cloud of the lens surface and quality evaluation of imaging was achieved. This simulation has been successfully measured the lens surface shape and shape distribution under the load which is difficult to measure on the experimental conditions. The integrated simulation method of the optical machine can obtain the change of the optical parameters brought by the temperature load. It shows that the application of Integrated analysis has play an important role in guiding the designing the lens.

  3. Development of an in vivo visual robot system with a magnetic anchoring mechanism and a lens cleaning mechanism for laparoendoscopic single-site surgery (LESS).

    Science.gov (United States)

    Feng, Haibo; Dong, Dinghui; Ma, Tengfei; Zhuang, Jinlei; Fu, Yili; Lv, Yi; Li, Liyi

    2017-12-01

    Surgical robot systems which can significantly improve surgical procedures have been widely used in laparoendoscopic single-site surgery (LESS). For a relative complex surgical procedure, the development of an in vivo visual robot system for LESS can effectively improve the visualization for surgical robot systems. In this work, an in vivo visual robot system with a new mechanism for LESS was investigated. A finite element method (FEM) analysis was carried out to ensure the safety of the in vivo visual robot during the movement, which was the most important concern for surgical purposes. A master-slave control strategy was adopted, in which the control model was established by off-line experiments. The in vivo visual robot system was verified by using a phantom box. The experiment results show that the robot system can successfully realize the expected functionalities and meet the demands of LESS. The experiment results indicate that the in vivo visual robot with high manipulability has great potential in clinical application. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Understanding critical barriers to implementing a clinical information system in a nursing home through the lens of a socio-technical perspective.

    Science.gov (United States)

    Or, Calvin; Dohan, Michael; Tan, Joseph

    2014-09-01

    This paper addresses key barriers to implementing a clinical information system (CIS) in a Hong Kong nursing home setting, from a healthcare specific socio-technical perspective. Data was collected through field observations (n = 12) and semi-structured individual interviews (n = 18) of CIS stakeholders in a Hong Kong nursing home, and analyzed using the immersion/crystallization approach. Complex interactions relevant to our case were contextualized and interpreted within the perspective of the Sittig-Singh Healthcare Socio-Technical Framework (HSTF). Three broad clusters of implementation barriers from the eight HSTF dimensions were identified: (a) Infrastructure-based barriers, which relate to conflict between government regulations and system functional needs of users; lack of financial support; inconsistency between workflow, work policy, and procedures; and inadequacy of hardware-software infrastructural and technical support; (b) Process-based barriers, which relate to mismatch between the technology, existing work practice and workflow, and communication; low system speed, accessibility, and stability; deficient computer literacy; more experience in health care profession; clinical content inadequacy and unavailability; as well as poor system usefulness and user interface design; and (c) Outcome-based barriers, which relate to the lack of measurement and monitoring of system effectiveness. Two additional dimensions underlining the importance of the ability of a CIS to change are proposed to extend the Sittig-Singh HSTF. First, advocacy would promote the articulation and influence of changes in the system and subsequent outcomes by CIS stakeholders, and second, adaptability would ensure the ability of the system to adjust to emerging needs. The broad set of discovered implementation shortcomings expands prior research on why CIS can fail in nursing home settings. Moreover, our investigation offers a knowledge base and recommendations that can serve

  5. 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.

  6. 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.

  7. Linking local knowledge with global action: examining the Global Fund to Fight AIDS, Tuberculosis and Malaria through a knowledge system lens.

    Science.gov (United States)

    van Kerkhoff, Lorrae; Szlezák, Nicole

    2006-08-01

    New global public health institutions are increasingly emphasizing transparency in decision-making, developing-country ownership of projects and programmes, and merit- and performance-based funding. Such principles imply an institutional response to the challenge of bridging the "know-do gap", by basing decisions explicitly on results, evidence and best practice. Using a knowledge systems framework, we examine how the Global Fund to Fight AIDS, Tuberculosis and Malaria has affected the ways in which knowledge is used in efforts to combat these three diseases. We outline the formal knowledge system embedded in current rules and practices associated with the Global Fund's application process, and give three examples that illustrate the complexity of the knowledge system in action: human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) policy in China; successful applications from Haiti; and responses to changing research on malaria. These examples show that the Global Fund has created strong incentives for knowledge to flow to local implementers, but with little encouragement and few structures for the potentially valuable lessons from implementation to flow back to global best practice or research-based knowledge. The Global Fund could play an influential role in fostering much-needed learning from implementation. We suggest that three initial steps are required to start this process: acknowledging shared responsibility for learning across the knowledge system; analysing the Global Fund's existing data (and refining data collection over time); and supporting recipients and technical partners to invest resources in linking implementation with best practice and research.

  8. 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.

  9. 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.)

  10. Evaluation of lens dose from anterior electron beams: comparison of Pinnacle and Gafchromic EBT3 film.

    Science.gov (United States)

    Sonier, Marcus; Wronski, Matt; Yeboah, Collins

    2015-03-08

    Lens dose is a concern during the treatment of facial lesions with anterior electron beams. Lead shielding is routinely employed to reduce lens dose and minimize late complications. The purpose of this work is twofold: 1) to measure dose pro-files under large-area lead shielding at the lens depth for clinical electron energies via film dosimetry; and 2) to assess the accuracy of the Pinnacle treatment planning system in calculating doses under lead shields. First, to simulate the clinical geometry, EBT3 film and 4 cm wide lead shields were incorporated into a Solid Water phantom. With the lead shield inside the phantom, the film was positioned at a depth of 0.7 cm below the lead, while a variable thickness of solid water, simulating bolus, was placed on top. This geometry was reproduced in Pinnacle to calculate dose profiles using the pencil beam electron algorithm. The measured and calculated dose profiles were normalized to the central-axis dose maximum in a homogeneous phantom with no lead shielding. The resulting measured profiles, functions of bolus thickness and incident electron energy, can be used to estimate the lens dose under various clinical scenarios. These profiles showed a minimum lead margin of 0.5 cm beyond the lens boundary is required to shield the lens to ≤ 10% of the dose maximum. Comparisons with Pinnacle showed a consistent overestimation of dose under the lead shield with discrepancies of ~ 25% occur-ring near the shield edge. This discrepancy was found to increase with electron energy and bolus thickness and decrease with distance from the lead edge. Thus, the Pinnacle electron algorithm is not recommended for estimating lens dose in this situation. The film measurements, however, allow for a reasonable estimate of lens dose from electron beams and for clinicians to assess the lead margin required to reduce the lens dose to an acceptable level.

  11. Noncontact optical measurement of lens capsule thickness ex vivo

    Science.gov (United States)

    Ziebarth, Noel M.; Manns, Fabrice; Uhlhorn, Stephen; Parel, Jean-Marie

    2004-07-01

    Purpose: To design a non-contact optical system to measure lens capsule thickness in cadaver eyes. Methods: The optical system uses a 670nm laser beam delivered to a single-mode fiber coupler. The output of the fiber coupler is focused onto the tissue using an aspheric lens (NA=0.68) mounted on a motorized translation stage. Light reflected from the sample is collected by the fiber coupler and sent to a silicon photodiode connected to a power meter. Peaks in the power signal are detected when the focal point of the aspheric lens coincides with the capsule boundaries. The capsule thickness is proportional to the distance between successive peaks. Anterior and posterior lens capsule thickness measurements were performed on 13 human, 10 monkey, and 34 New Zealand white rabbit lenses. The cadaver eyes were prepared for optical measurements by bonding a PMMA ring on the sclera. The posterior pole was sectioned, excess vitreous was removed, and the eye was placed on a Teflon slide. The cornea and iris were then sectioned. After the experiments, the lenses were excised, placed in 10% buffered formalin, and prepared for histology. Results: Central anterior lens capsule thickness was 9.4+/-2.9μm (human), 11.2+/-6.6μm (monkey), and 10.3+/-3.6μm (rabbit) optically and 14.9+/-1.6μm (human), 17.7+/-4.9μm (monkey), and 12.6+/-2.3μm (rabbit) histologically. The values for the central posterior capsule were 9.4+/-2.9μm (human), 6.6+/-2.5μm (monkey), and 7.9+/-2.3μm (rabbit) optically and 4.6+/-1.4μm (human), 4.5+/-1.2μm (monkey), and 5.7+/-1.7μm (rabbit) histologically. Conclusions: This study demonstrates that a non-contact optical system can successfully measure lens capsule thickness in cadaver eyes.

  12. 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.

  13. 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.

  14. 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.

  15. Development of a Novel Embedded Relay Lens Microscopic Hyperspectral Imaging System for Cancer Diagnosis: Use of the Mice with Oral Cancer to Be the Example

    Directory of Open Access Journals (Sweden)

    Yao-Fang Hsieh

    2012-01-01

    the fluorescence of cells or tissue can provide the characteristic signature for identification of normal and abnormal. In this work, the development of the ERL-MHSI system is discussed and the capability of the system is demonstrated by diagnosing early stage oral cancer of twenty mice in vitro. The best sensitivity for identifying normal cells and squamous cell carcinoma (SCC was 100%. The best specificity for identifying normal cells and SCC was 99%. The best sensitivity for identifying normal cells and dysplasia was 99%. The best specificity for identifying normal cells and dysplasia was 97%. This work also utilizes fractal dimension to analyze the morphological information and find the significant different values between normal and SCC.

  16. Automated Micro-Object Detection for Mobile Diagnostics Using Lens-Free Imaging Technology

    Directory of Open Access Journals (Sweden)

    Mohendra Roy

    2016-05-01

    Full Text Available Lens-free imaging technology has been extensively used recently for microparticle and biological cell analysis because of its high throughput, low cost, and simple and compact arrangement. However, this technology still lacks a dedicated and automated detection system. In this paper, we describe a custom-developed automated micro-object detection method for a lens-free imaging system. In our previous work (Roy et al., we developed a lens-free imaging system using low-cost components. This system was used to generate and capture the diffraction patterns of micro-objects and a global threshold was used to locate the diffraction patterns. In this work we used the same setup to develop an improved automated detection and analysis algorithm based on adaptive threshold and clustering of signals. For this purpose images from the lens-free system were then used to understand the features and characteristics of the diffraction patterns of several types of samples. On the basis of this information, we custom-developed an automated algorithm for the lens-free imaging system. Next, all the lens-free images were processed using this custom-developed automated algorithm. The performance of this approach was evaluated by comparing the counting results with standard optical microscope results. We evaluated the counting results for polystyrene microbeads, red blood cells, and HepG2, HeLa, and MCF7 cells. The comparison shows good agreement between the systems, with a correlation coefficient of 0.91 and linearity slope of 0.877. We also evaluated the automated size profiles of the microparticle samples. This Wi-Fi-enabled lens-free imaging system, along with the dedicated software, possesses great potential for telemedicine applications in resource-limited settings.

  17. Influence of genetic diversity on cause and effect relationships in lens culinaris germplasm under rain-fed eco-agricultural system

    International Nuclear Information System (INIS)

    Ilyas, M.; Arshad, M.; Ghafoor, A.

    2014-01-01

    Due to emerging demands of organic foods, lentil, one of the most primitive legumes was investigated for genetic diversity including cause and effect relationships among various clusters under eco-agricultural system. The 73 lentil genotypes were investigated for qualitative and quantitative traits to identify the potential lines under rain-fed conditions for organic farming using no chemical fertilizers for crop production. Variation existed for all the qualitative traits including orange cotyledon colour in 27 genotypes which is a preferred trait by Asian consumers including Pakistan. Five clusters revealed that average intra-clusters distances were more or less similar, whereas inter-cluster distance indicated higher level of genetic diversity. First three PCs contributed more than 3/4 of the variability and the results were in coordination with clustering pattern amongst 73 genotypes. The populations contributing the first PC were late in maturity possessed higher number of branches, pods, better biomass and grain yield. The PC/sub 2/ was more contributed by seeds pod-1 and seed diameter, whereas pod length and harvest index contributed 13% variability. The cause and effect relationships indicated differential response for selection of lentil genotypes suitable for eco-agricultural system within each cluster. (author)

  18. Ball lens based lensed patch cord probes for optical coherence tomography in the field of dentistry

    Science.gov (United States)

    Eom, J. B.; Kim, Y.; Lee, S. J.; Min, E. J.; Park, S. J.; Lee, B. H.

    2012-10-01

    A lensed patch cord probe has been made with a ball lens packaged in a metal cylinder. By simply placing a ball lens directly in front of a fiber patch cord, a compact and potentially disposable sampling probe for optical coherence tomography (OCT) could be implemented. To achieve a sufficiently long working distance and a good transverse resolution simultaneously, the proper ball lens diameter and the distance between the ball lens and the fiber patch cord were investigated. Experimentally, a working distance of up to 5.2 mm, 3 dB bandwidth of 2 mm, and transverse resolution of 16 μm were achieved. With the patch cord probe, a common path swept source OCT system was implemented and used to demonstrate the feasibility as the dedicated probe for dentistry.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Assessment of Microcirculatory Hemoglobin Levels in Normal and Diabetic Subjects using Diffuse Reflectance Spectroscopy in the Visible Region — a Pilot Study

    Science.gov (United States)

    Sujatha, N.; Anand, B. S. Suresh; Nivetha, K. Bala; Narayanamurthy, V. B.; Seshadri, V.; Poddar, R.

    2015-07-01

    Light-based diagnostic techniques provide a minimally invasive way for selective biomarker estimation when tissues transform from a normal to a malignant state. Spectroscopic techniques based on diffuse reflectance characterize the changes in tissue hemoglobin/oxygenation levels during the tissue transformation process. Recent clinical investigations have shown that changes in tissue oxygenation and microcirculation are observed in diabetic subjects in the initial and progressive stages. In this pilot study, we discuss the potential of diffuse reflectance spectroscopy (DRS) in the visible (Vis) range to differentiate the skin microcirculatory hemoglobin levels between normal and advanced diabetic subjects with and without neuropathy. Average concentration of hemoglobin as well as hemoglobin oxygen saturation within the probed tissue volume is estimated for a total of four different sites in the foot sole. The results indicate a statistically significant decrease in average total hemoglobin and increase in hemoglobin oxygen saturation levels for diabetic foot compared with a normal foot. The present study demonstrates the ability of reflectance spectroscopy in the Vis range to determine and differentiate the changes in tissue hemoglobin and hemoglobin oxygen saturation levels in normal and diabetic subjects.

  5. Coronary physiological assessment combining fractional flow reserve and index of microcirculatory resistance in patients undergoing elective percutaneous coronary intervention with grey zone fractional flow reserve.

    Science.gov (United States)

    Niida, Takayuki; Murai, Tadashi; Yonetsu, Taishi; Kanaji, Yoshihisa; Usui, Eisuke; Matsuda, Junji; Hoshino, Masahiro; Araki, Makoto; Yamaguchi, Masao; Hada, Masahiro; Ichijyo, Sadamitsu; Hamaya, Rikuta; Kanno, Yoshinori; Isobe, Mitsuaki; Kakuta, Tsunekazu

    2018-03-08

    The aim of this study is to investigate the association between fractional flow reserve (FFR) values and change in coronary physiological indices after elective percutaneous coronary intervention (PCI). Decision making for revascularization when FFR is 0.75-0.80 is controversial. A retrospective analysis was performed of 296 patients with stable angina pectoris who underwent physiological examinations before and after PCI. To investigate the differences of coronary flow improvement between territories with low-FFR (zone FFR (0.75-0.80), serial changes in physiological indices including mean transit time (Tmn), coronary flow reserve (CFR), and index of microcirculatory resistance (IMR) were compared between these two groups. Compared to low-FFR territories, grey-zone FFR territories showed significantly lower prevalence of Tmn shortening, CFR improvement, and decrease in IMR (Tmn shorting, 63.9% vs. 87.0%, P 51.3% vs. 63.3%, P = .040) and lower extent of their absolute changes (Tmn shorting, 0.06 (-0.03 to 0.16) vs. 0.22 (0.07-0.45), P zone FFR. Physiological assessment combining FFR and IMR may help identify patients who may benefit by PCI, particularly those in the grey zone. © 2018 Wiley Periodicals, Inc.

  6. Ameliorating effects of traditional Chinese medicine preparation, Chinese materia medica and active compounds on ischemia/reperfusion-induced cerebral microcirculatory disturbances and neuron damage.

    Science.gov (United States)

    Sun, Kai; Fan, Jingyu; Han, Jingyan

    2015-01-01

    Ischemic stroke and ischemia/reperfusion (I/R) injury induced by thrombolytic therapy are conditions with high mortality and serious long-term physical and cognitive disabilities. They have a major impact on global public health. These disorders are associated with multiple insults to the cerebral microcirculation, including reactive oxygen species (ROS) overproduction, leukocyte adhesion and infiltration, brain blood barrier (BBB) disruption, and capillary hypoperfusion, ultimately resulting in tissue edema, hemorrhage, brain injury and delayed neuron damage. Traditional Chinese medicine (TCM) has been used in China, Korea, Japan and other Asian countries for treatment of a wide range of diseases. In China, the usage of compound TCM preparation to treat cerebrovascular diseases dates back to the Han Dynasty. Even thousands of years earlier, the medical formulary recorded many classical prescriptions for treating cerebral I/R-related diseases. This review summarizes current information and underlying mechanisms regarding the ameliorating effects of compound TCM preparation, Chinese materia medica, and active components on I/R-induced cerebral microcirculatory disturbances, brain injury and neuron damage.

  7. Ameliorating effects of traditional Chinese medicine preparation, Chinese materia medica and active compounds on ischemia/reperfusion-induced cerebral microcirculatory disturbances and neuron damage

    Directory of Open Access Journals (Sweden)

    Kai Sun

    2015-01-01

    Full Text Available Ischemic stroke and ischemia/reperfusion (I/R injury induced by thrombolytic therapy are conditions with high mortality and serious long-term physical and cognitive disabilities. They have a major impact on global public health. These disorders are associated with multiple insults to the cerebral microcirculation, including reactive oxygen species (ROS overproduction, leukocyte adhesion and infiltration, brain blood barrier (BBB disruption, and capillary hypoperfusion, ultimately resulting in tissue edema, hemorrhage, brain injury and delayed neuron damage. Traditional Chinese medicine (TCM has been used in China, Korea, Japan and other Asian countries for treatment of a wide range of diseases. In China, the usage of compound TCM preparation to treat cerebrovascular diseases dates back to the Han Dynasty. Even thousands of years earlier, the medical formulary recorded many classical prescriptions for treating cerebral I/R-related diseases. This review summarizes current information and underlying mechanisms regarding the ameliorating effects of compound TCM preparation, Chinese materia medica, and active components on I/R-induced cerebral microcirculatory disturbances, brain injury and neuron damage.

  8. 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...

  9. CMU DeepLens: deep learning for automatic image-based galaxy-galaxy strong lens finding

    Science.gov (United States)

    Lanusse, François; Ma, Quanbin; Li, Nan; Collett, Thomas E.; Li, Chun-Liang; Ravanbakhsh, Siamak; Mandelbaum, Rachel; Póczos, Barnabás

    2018-01-01

    Galaxy-scale strong gravitational lensing can not only provide a valuable probe of the dark matter distribution of massive galaxies, but also provide valuable cosmological constraints, either by studying the population of strong lenses or by measuring time delays in lensed quasars. Due to the rarity of galaxy-scale strongly lensed systems, fast and reliable automated lens finding methods will be essential in the era of large surveys such as Large Synoptic Survey Telescope, Euclid and Wide-Field Infrared Survey Telescope. To tackle this challenge, we introduce CMU DeepLens, a new fully automated galaxy-galaxy lens finding method based on deep learning. This supervised machine learning approach does not require any tuning after the training step which only requires realistic image simulations of strongly lensed systems. We train and validate our model on a set of 20 000 LSST-like mock observations including a range of lensed systems of various sizes and signal-to-noise ratios (S/N). We find on our simulated data set that for a rejection rate of non-lenses of 99 per cent, a completeness of 90 per cent can be achieved for lenses with Einstein radii larger than 1.4 arcsec and S/N larger than 20 on individual g-band LSST exposures. Finally, we emphasize the importance of realistically complex simulations for training such machine learning methods by demonstrating that the performance of models of significantly different complexities cannot be distinguished on simpler simulations. We make our code publicly available at https://github.com/McWilliamsCenter/CMUDeepLens.

  10. Assessment of Malawi’s success in child mortality reduction through the lens of the Catalytic Initiative Integrated Health Systems Strengthening programme: Retrospective evaluation

    Directory of Open Access Journals (Sweden)

    Tanya Doherty

    2015-12-01

    Full Text Available Malawi is estimated to have achieved its Millennium Development Goal (MDG 4 target. This paper explores factors influencing progress in child survival in Malawi including coverage of interventions and the role of key national policies. We performed a retrospective evaluation of the Catalytic Initiative (CI programme of support (2007–2013. We developed estimates of child mortality using four population household surveys undertaken between 2000 and 2010. We recalculated coverage indicators for high impact child health interventions and documented child health programmes and policies. The Lives Saved Tool (LiST was used to estimate child lives saved in 2013. The mortality rate in children under 5 years decreased rapidly in the 10 CI districts from 219 deaths per 1000 live births (95% confidence interval (CI 189 to 249 in the period 1991–1995 to 119 deaths (95% CI 105 to 132 in the period 2006–2010. Coverage for all indicators except vitamin A supplementation increased in the 10 CI districts across the time period 2000 to 2013. The LiST analysis estimates that there were 10 800 child deaths averted in the 10 CI districts in 2013, primarily attributable to the introduction of the pneumococcal vaccine (24% and increased household coverage of insecticide–treated bednets (19%. These improvements have taken place within a context of investment in child health policies and scale up of integrated community case management of childhood illnesses. Malawi provides a strong example for countries in sub–Saharan Africa of how high impact child health interventions implemented within a decentralised health system with an established community–based delivery platform, can lead to significant reductions in child mortality.

  11. 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.

  12. Glass molding of 3mm diameter aspheric plano-convex lens

    Science.gov (United States)

    Sung, Hayeong; Hue, Myung sang; Lee, Giljae; Ryu, Geunman; Kim, Dongguk; Yang, Suncheol

    2017-10-01

    The many industries and research fields have demands for small scale optical systems. To satisfy the demands, many studies are conducted and the miniaturization technologies have been developed. The optical lens is directly related to the optical systems and a key component for the miniaturization. So the aspheric surface which can replace multispherical lenses is applied to the optical lens. And fabrication methods to reduce the diameter of the lens have been developed. The glass molding pressing (GMP) process is an attractive method to fabricate aspheric lens among the lens manufacturing processes. Because the GMP process has advantages of productivity, repeatability and so on. In this study, a 3 mm diameter aspheric plano-convex lens was fabricated using the GMP process. The GMP process was divided into heating, pressing, annealing and cooling. And the process was conducted using a commercial glass molding machine. Mold tools consist of an upper and a lower mold insert, an inner and an outer guide. The aspheric and the flat surfaces of the mold inserts were coated with ta-C to prevent the sticking of the glass to the mold. The surfaces of molded lens were measured by white interferometry and surface profilometer. The height and the diameter were measured using optical microscopy. As results, the aspheric surface of the lens was 5.1187 nm in Ra and 0.242 um in Pt. And the flat surface was 2.6697 nm in Ra and 0.13 um in Pt. The height and the diameter were 1.935 mm and 3.002 mm respectively.

  13. The Charles F. Prentice award lecture 2009: Crystalline lens research and serendipity in science.

    Science.gov (United States)

    Sivak, Jacob Gershon

    2010-09-01

    Whether it is called serendipity or creativity, the process of scientific discovery is not one that lends itself to advance planning or programming, nor does it lend itself to an emphasis solely on applied research, research with industrial partners, or large teams of researchers because researchers must rely on intuition and the capacity to move quickly in new directions. Studies in my laboratory began with efforts to relate lens embryonic development to lens optical performance in a variety of vertebrate species. The initial direction concerned the optics of the fish eye, a system in which a spherical lens is essentially the only refractive component of the eye and one in which accommodation takes place by means of lens movement. This in turn led to an interest in how amphibious animals cope with the refractive transition that takes place when moving from air to water and vice versa. The development of a super accommodative ability in some diving birds is one adaptation that was explored. These curiosity-driven efforts led in turn to the development of a scanning laser system that provided a tool that can be used to evaluate the process of cataract development, either on the basis of in vivo exposure to chemicals or electromagnetic radiation and subsequent analysis of the excised lens or to the in vitro study of the lens in long-term whole lens culture experiments. The same approach has also been used as an in vitro ocular toxicology assay to develop sensitive in vitro methods to reduce regulatory dependence on the use of live animals. Finally, these applied directions in turn created new basic knowledge concerning the morphology and physiology of eye tissue organelles, particularly the morphology, distribution, and dynamic properties of the mitochondria found in the lens and in the retinal pigment epithelium.

  14. A new concept of a hybrid trapped field magnet lens

    Science.gov (United States)

    Takahashi, Keita; Fujishiro, Hiroyuki; Ainslie, Mark D.

    2018-04-01

    In this paper, a new concept of a hybrid trapped field magnet lens (HTFML) is proposed. The HTMFL exploits the ‘vortex pinning effect’ of an outer superconducting bulk cylinder, which is magnetized as a trapped field magnet (TFM) using field-cooled magnetization (FCM), and the ‘diamagnetic shielding effect’ of an inner bulk magnetic lens to generate a concentrated magnetic field higher than the trapped field from the TFM in the bore of the magnetic lens. This requires that, during the zero-field-cooled magnetization process, the outer cylinder is in the normal state (T> superconducting transition temperature, T c) and the inner lens is in the superconducting state (T magnetizing field is applied, followed by cooling to an appropriate operating temperature, then removing the external field. This is explored for two potential cases: (1) exploiting the difference in T c of two different bulk materials (‘case-1’), e.g. MgB2 (T c = 39 K) and GdBaCuO (T c = 92 K) or (2) using the same material for the whole HTFML, e.g., GdBaCuO, but utilizing individually controlled cryostats, the same cryostat with different cooling loops or coolants, or heaters that keep the outer bulk cylinder at a temperature above T c to achieve the same desired effect. The HTFML is verified using numerical simulations for ‘case-1’ using an MgB2 cylinder and GdBaCuO lens pair and for ‘case-2’ using a GdBaCuO cylinder and GdBaCuO lens pair. As a result, the HTFML could reliably generate a concentrated magnetic field B c = 4.73 T with the external magnetizing field B app = 3 T in the ‘case-1’, and a higher B c = 13.49 T with higher B app = 10 T in the ‘case-2’, respectively. This could, for example, be used to enhance the magnetic field in the bore of a bulk superconducting NMR/MRI system to improve its resolution.

  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. 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.

  1. Ice-lens formation and geometrical supercooling in soils and other colloidal materials

    KAUST Repository

    Style, Robert W.

    2011-10-14

    We present a physically intuitive model of ice-lens formation and growth during the freezing of soils and other dense, particulate suspensions. Motivated by experimental evidence, we consider the growth of an ice-filled crack in a freezing soil. At low temperatures, ice in the crack exerts large pressures on the crack walls that will eventually cause the crack to split open. We show that the crack will then propagate across the soil to form a new lens. The process is controlled by two factors: the cohesion of the soil and the geometrical supercooling of the water in the soil, a new concept introduced to measure the energy available to form a new ice lens. When the supercooling exceeds a critical amount (proportional to the cohesive strength of the soil) a new ice lens forms. This condition for ice-lens formation and growth does not appeal to any ad hoc, empirical assumptions, and explains how periodic ice lenses can form with or without the presence of a frozen fringe. The proposed mechanism is in good agreement with experiments, in particular explaining ice-lens pattern formation and surges in heave rate associated with the growth of new lenses. Importantly for systems with no frozen fringe, ice-lens formation and frost heave can be predicted given only the unfrozen properties of the soil. We use our theory to estimate ice-lens growth temperatures obtaining quantitative agreement with the limited experimental data that are currently available. Finally we suggest experiments that might be performed in order to verify this theory in more detail. The theory is generalizable to complex natural-soil scenarios and should therefore be useful in the prediction of macroscopic frost-heave rates. © 2011 American Physical Society.

  2. Staff exposure in pediatric interventional neuroradiology: focus on the operator's eye lens

    International Nuclear Information System (INIS)

    Bolomey, C.; Fasel, G.; Le Coultre, R.; Ryckx, N.

    2016-01-01

    Previously at 150 mSv year -1 , the ICRP now recommends limiting the equivalent dose to the eye lens to 20 mSv year -1 . For pediatric interventional neuroradiology, the exposure of the operator's eye lens may be increased by the use of a biplane fluoroscopy system and by the proximity of the physician to the patient. In practice, the efficiency of leaded glasses depends on many factors. This study addresses both aspects. First, the eye lens dose of a neuro-radiologist was measured during 12 procedures using 36 TLDs placed on his surgical cap. Secondly, in order to determine the efficiency of leaded glasses, measurements were carried out by reproducing the clinical conditions. A detector was placed on the left eye of a phantom representing the operator. Four pairs of leaded glasses were selected to test various parameters. During the 12 procedures, an individual dose equivalent Hp(0.07) of 45μSv was obtained for the eye lens closest to the tube. This study shows an eye lens dose to DAP ratio 5 times higher than for procedures performed on adult patients. The eye lens dose might be reduced by a factor of approximately 3 with the use of appropriate leaded glasses. The eye wear model with the most coverage reduces the dose by up to 50% more than the model with the least coverage. The addition of lateral protection increases the attenuation by up to 13% compared with the same model without side protection. (authors)

  3. DotLens smartphone microscopy for biological and biomedical applications (Conference Presentation)

    Science.gov (United States)

    Sung, Yu-Lung; Zhao, Fusheng; Shih, Wei-Chuan

    2017-02-01

    Recent advances in inkjet-printed optics have created a new class of lens fabrication technique. Lenses with a tunable geometry, magnification, and focal length can be fabricated by dispensing controlled amounts of liquid polymer onto a heated surface. This fabrication technique is highly cost-effective, and can achieve optically smooth surface finish. Dubbed DotLens, a single of which weighs less than 50 mg and occupies a volume less than 50 μL. DotLens can be attached onto any smartphone camera akin to a contact lens, and enable smartphones to obtain image resolution as fine as 1 µm. The surface curvature modifies the optical path of light to the image sensor, and enables the camera to focus as close as 2 mm. This enables microscopic imaging on a smartphone without any additional attachments, and has shown great potential in mobile point-of-care diagnostic systems, particularly for histology of tissue sections and cytology of blood cells. DotLens Smartphone Microscopy represents an innovative approach fundamentally different from other smartphone microscopes. In this paper, we describe the application and performance of DotLens smartphone microscopy in biological and biomedical research. In particular, we show recent results from images collected from pathology tissue slides with cancer features. In addition, we show performance in cytological analysis of blood smear. This tool has empowered Citizen Science investigators to collect microscopic images from various interesting objects.

  4. Semiautomated analysis of optical coherence tomography crystalline lens images under simulated accommodation.

    Science.gov (United States)

    Kim, Eon; Ehrmann, Klaus; Uhlhorn, Stephen; Borja, David; Arrieta-Quintero, Esdras; Parel, Jean-Marie

    2011-05-01

    Presbyopia is an age related, gradual loss of accommodation, mainly due to changes in the crystalline lens. As part of research efforts to understand and cure this condition, ex vivo, cross-sectional optical coherence tomography images of crystalline lenses were obtained by using the Ex-Vivo Accommodation Simulator (EVAS II) instrument and analyzed to extract their physical and optical properties. Various filters and edge detection methods were applied to isolate the edge contour. An ellipse is fitted to the lens outline to obtain central reference point for transforming the pixel data into the analysis coordinate system. This allows for the fitting of a high order equation to obtain a mathematical description of the edge contour, which obeys constraints of continuity as well as zero to infinite surface slopes from apex to equator. Geometrical parameters of the lens were determined for the lens images captured at different accommodative states. Various curve fitting functions were developed to mathematically describe the anterior and posterior surfaces of the lens. Their differences were evaluated and their suitability for extracting optical performance of the lens was assessed. The robustness of these algorithms was tested by analyzing the same images repeated times.

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

    Science.gov (United States)

    Brodersen, Craig R; Vogelmann, Thomas C

    2007-07-01

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

  6. A study of optical design and optimization applied to lens module of laser beam shaping of advanced modern optical device

    Science.gov (United States)

    Tsai, Cheng-Mu; Fang, Yi-Chin; Chen, Zhen Hsiang

    2011-10-01

    This study used the aspheric lens to realize the laser flat-top optimization, and applied the genetic algorithm (GA) to find the optimal results. Using the characteristics of aspheric lens to obtain the optimized high quality Nd: YAG 355 waveband laser flat-top optical system, this study employed the Light tools LDS (least damped square) and the GA of artificial intelligence optimization method to determine the optimal aspheric coefficient and obtain the optimal solution. This study applied the aspheric lens with GA for the flattening of laser beams using two aspheric lenses in the aspheric surface optical system to complete 80% spot narrowing under standard deviation of 0.6142.

  7. 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.

  8. 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.

  9. 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.

  10. Material Structure of a Graded Refractive Index Lens in Decapod Squid

    Science.gov (United States)

    Cai, Jing; Heiney, Paul; Sweeney, Alison

    2013-03-01

    Underwater vision with a camera-type eye that is simultaneously acute and sensitive requires a spherical lens with a graded distribution of refractive index. Squids have this type of lens, and our previous work has shown that its optical properties are likely achieved with radially variable densities of a single protein with multiple isoforms. Here we measure the spatial organization of this novel protein material in concentric layers of the lens and use these data to suggest possible mechanisms of self-assembly of the proteins into a graded refractive index structure. First, we performed small angle x-ray scattering (SAXS) to study how the protein is spatially organized. Then, molecular dynamic simulation allowed us to correlate structure to the possible dynamics of the system in different regions of the lens. The combination of simulation and SAXS data in this system revealed the likely protein-protein interactions, resulting material structure and its relationship to the observed and variable optical properties of this graded index system. We believe insights into the material properties of the squid lens system will inform the invention of self-assembling graded index devices.

  11. Evaluation of RGP Contact Lens Fitting in Keratoconus Patients Using Hierarchical Fuzzy Model and Genetic Algorithms.

    Science.gov (United States)

    Falahati Marvast, Fatemeh; Arabalibeik, Hossein; Alipour, Fatemeh; Sheikhtaheri, Abbas; Nouri, Leila; Soozande, Mehdi; Yarmahmoodi, Masood

    2016-01-01

    Keratoconus is a progressive non-inflammatory disease of the cornea. Rigid gas permeable contact lenses (RGPs) are prescribed when the disease progresses. Contact lens fitting and assessment is very difficult in these patients and is a concern of ophthalmologists and optometrists. In this study, a hierarchical fuzzy system is used to capture the expertise of experienced ophthalmologists during the lens evaluation phase of prescription. The system is fine-tuned using genetic algorithms. Sensitivity, specificity and accuracy of the final system are 88.9%, 94.4% and 92.6% respectively.

  12. 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.

  13. 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.

  14. 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.

  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. Assessing the Effects of Acupuncture by Comparing Needling the Hegu Acupoint and Needling Nearby Nonacupoints by Spectral Analysis of Microcirculatory Laser Doppler Signals

    Directory of Open Access Journals (Sweden)

    Hsin Hsiu

    2011-01-01

    Full Text Available We aimed to assess the effects of acupuncture by analyzing the frequency content of skin blood-flow signals simultaneously recorded at the Hegu acupoint and two nearby nonacupoints following acupuncture stimulation (AS. Laser Doppler flowmetry (LDF signals were measured in male healthy volunteers in two groups of experiments: needling the Hegu acupoint (n = 13 and needling a nearby nonacupoint (control experiment; n = 10. Each experiment involved recording a 20 min baseline-data sequence and two sets of effects data recorded 0–20 and 50–70 min after stopping AS. Wavelet transform with Morlet mother wavelet was applied to the measured LDF signals. Needling the Hegu acupoint significantly increased the blood flow, significantly decreased the relative energy contribution at 0.02–0.06 Hz and significantly increased the relative energy contribution at 0.4–1.6 Hz at Hegu, but induced no significant changes at the nonacupoints. Also, needling a nearby nonacupoint had no effect in any band at any site. This is the first time that spectral analysis has been used to investigate the microcirculatory blood-flow responses induced by AS, and has revealed possible differences in sympathetic nerve activities between needling the Hegu acupoint and its nearby nonacupoint. One possible weakness of the present design is that different De-Qi feelings following AS could lead to nonblind experimental setup, which may bias the comparison between needling Hegu and its nearby nonacupoint. Our results suggest that the described noninvasive method can be used to evaluate sympathetic control of peripheral vascular activity, which might be useful for studying the therapeutic effects of AS.

  17. SU-E-J-69: Evaluation of the Lens Dose On the Cone Beam IGRT Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Palomo-Llinares, R; Gimeno-Olmos, J; Carmona Meseguer, V; Lliso-Valverde, F; Candela-Juan, C; Perez-Calatayud, J [Hospital La Fe, Valencia, Valencia (Spain); Pujades, M [National Dosimetry Center, Valencia, Valencia (Spain); Ballester, F [University of Valencia, Burjassot (Spain)

    2014-06-01

    Purpose: With the establishment of the IGRT as a standard technique, the extra dose that is given to the patients should be taken into account. Furthermore, it has been a recent decrease of the dose threshold in the lens, reduced to 0.5 Gy (ICRP ref 4825-3093-1464 on 21st April, 2011).The purpose of this work was to evaluate the extra dose that the lens is receive due to the Cone-Beam (CBCT) location systems in Head-and-Neck treatments. Methods: The On-Board Imaging (OBI) v 1.5 of the two Varian accelerators, one Clinac iX and one True Beam, were used to obtain the dose that this OBI version give to the lens in the Head-and-Neck location treatments. All CBCT scans were acquired with the Standard Dose Head protocol (100 kVp, 80 mA, 8 ms and 200 degree of rotation).The measurements were taken with thermoluminescence (TLD) EXTRAD (Harshaw) dosimeters placed in an anthropomorphic phantom over the eye and under 3 mm of bolus material to mimic the lens position. The center of the head was placed at the isocenter. To reduce TLD energy dependence, they were calibrated at the used beam quality. Results: The average lens dose at the lens in the OBI v 1.5 systems of the Clinac iX and the True Beam is 0.071 and 0.076 cGy/CBCT, respectively. Conclusions: The extra absorbed doses that receive the eye lenses due to one CBCT acquisition with the studied protocol is far below the new ICRP recommended threshold for the lens. However, the addition effect of several CBCT acquisition during the whole treatment should be taken into account.

  18. Imaging the Lenses in the Quintuple Gravitational Lens PMN J0134-0931

    Science.gov (United States)

    Wiklind, Tommy

    2017-08-01

    The gravitational lens PMN J0134-0931 is one of only two known non-cluster lenses producing six images of the background source. In this case the source is a quasar located at z=2.2 and the lens plane at z=0.76. It is likely that a small compact group of galaxies are located in the lens plane. The lens modeling for these six-image systems has, however, proven to be extraordinarily complicated and no satisfactory lens model has been produced for this system.PMN J0194-0931 is also unique in the sense that it is one of only two cases where molecular absorption lines are seen against two or more background images, the other one being PKS1830-211. The absorption lines make it possible to probe the kinematics of the lensing galaxies on sub-kpc scales and to determine kinematically derived total masses. Comparing with the mass derived from lens models, it provides a test of the assumed dark matter halo profile. In order to use the absorption lines to constrain the rotation curve it is necessary to know where the sigh lines cross the galaxies, the galaxy center and their inclination.The goal with this proposal is to image the galaxies at z=0.76 that lens the background quasar PMN J0134-0931. At optical and near-infrared wavelengths the highly magnified background quasar dominates the light. Attempts to subtract the quasar light has not produced useable results. We propose to observe PMN J0134-0931 at a wavelength short of the redshifted Lyman limit of the background quasar. This ensures that the quasar is essentially turned off. This can be accomplished by using the WFC3/F275W filter. The lensing galaxies will be observed in restframe 1500A.

  19. Deep convolutional neural networks as strong gravitational lens detectors

    Science.gov (United States)

    Schaefer, C.; Geiger, M.; Kuntzer, T.; Kneib, J.-P.

    2018-03-01

    Context. Future large-scale surveys with high-resolution imaging will provide us with approximately 105 new strong galaxy-scale lenses. These strong-lensing systems will be contained in large data amounts, however, which are beyond the capacity of human experts to visually classify in an unbiased way. Aim. We present a new strong gravitational lens finder based on convolutional neural networks (CNNs). The method was applied to the strong-lensing challenge organized by the Bologna Lens Factory. It achieved first and third place, respectively, on the space-based data set and the ground-based data set. The goal was to find a fully automated lens finder for ground-based and space-based surveys that minimizes human inspection. Methods: We compared the results of our CNN architecture and three new variations ("invariant" "views" and "residual") on the simulated data of the challenge. Each method was trained separately five times on 17 000 simulated images, cross-validated using 3000 images, and then applied to a test set with 100 000 images. We used two different metrics for evaluation, the area under the receiver operating characteristic curve (AUC) score, and the recall with no false positive (Recall0FP). Results: For ground-based data, our best method achieved an AUC score of 0.977 and a Recall0FP of 0.50. For space-based data, our best method achieved an AUC score of 0.940 and a Recall0FP of 0.32. Adding dihedral invariance to the CNN architecture diminished the overall score on space-based data, but achieved a higher no-contamination recall. We found that using committees of five CNNs produced the best recall at zero contamination and consistently scored better AUC than a single CNN. Conclusions: We found that for every variation of our CNN lensfinder, we achieved AUC scores close to 1 within 6%. A deeper network did not outperform simpler CNN models either. This indicates that more complex networks are not needed to model the simulated lenses. To verify this, more

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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

  5. 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.

  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. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  10. 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.

  11. 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.

  12. 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).

  13. 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...

  14. 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 ...

  15. A Comparison of Lens-Coupled Area Detector DR to Conventional Radiography

    International Nuclear Information System (INIS)

    Poland, R.W.

    2001-01-01

    Savannah River Technology Center filmless radiographic imaging system specialists have been ''champions'' of filmless radiographic imaging at the Savannah River Site since 1993. Recently a study was done comparing the differences between conventional film radiography and lens-coupled, charge-coupled-device digital radiography. Characteristics of both imaging methods that were considered in the study included resolution, latitude (called dynamic range by digital radiography imaging specialists), and modulation transfer functions. The results of those comparative experiments will be presented. A description of the lens-coupled, digital radiography imaging system will be provided

  16. 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.

  17. Common path ball lens probe for optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Singh, Kanwarpal; Yamada, Daisuke; Tearney, Guillermo J.

    2016-02-01

    Background: Common path probes are highly desirable for optical coherence tomography (OCT) as they reduce system complexity and cost. In this work we report an all-fiber common path side viewing monolithic probe for coronary artery imaging. Methods: Our common path probe was designed for spectrometer based Fourier domain OCT at 1310 nm wavelength. Light from the fiber expands in the coreless fiber region and then focussed by the ball lens. Reflection from ball lens-air interface served as reference signal. The monolithic ball lens probe was assembled within a 560 µmouter diameter drive shaft which was attached to a rotary junction. The drive shaft was placed inside an outer, transparent sheath of 800 µm diameter. Results: With a source input power of 25 mW, we could achieve sensitivity of 100.5 dB. The axial resolution of the system was found to be 15.6 µm in air and the lateral resolution (full width half maximum) was approximately 49 µm. As proof of principal, images of skin acquired using this probe demonstrated clear visualization of the stratum corneum, epidermis, and papillary dermis, along with sweat ducts. Conclusion: In this work we have demonstrated a monolithic, ball lens common, path probe for OCT imaging. The designed ball lens probe is easy to fabricate using a laser splicer. Based on the features and capability of common path probes to provide a simpler solution for OCT, we believe that this development will be an important enhancement for certain types of catheters.

  18. A Simple Model of the Accommodating Lens of the Human Eye

    Science.gov (United States)

    Oommen, Vinay; Kanthakumar, Praghalathan

    2014-01-01

    The human eye is often discussed as optically equivalent to a photographic camera. The iris is compared with the shutter, the pupil to the aperture, and the retina to the film, and both have lens systems to focus rays of light. Although many similarities exist, a major difference between the two systems is the mechanism involved in focusing an…

  19. 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....

  20. Effect of gamma irradiation on in vitro bovine lens proteins

    International Nuclear Information System (INIS)

    Bernardes, D.M.L.; Mastro, N.L. del.

    1988-07-01

    The radiosensitivity of the ocular lens manifested by cataract formation has been of considerable interest in the study on the biological efects of radiations. Cataract can ben produced by different causes and also for the normal process of ageing. The aim of this work was to develop an in vitro system similar to in vivo cataract formation. It was used an aqueous solution of bovine lenses. The lenses after surgical removal mechanical and ultrasonic disrupted. The suspension was centrifuged and the supernatant was dialyzed and irradiated with different doses of 60 Co radiation. The opacification extent was measured in an spectrophotometer. (author) [pt

  1. Consumer electronic optics: how small can a lens be: the case of panomorph lenses

    Science.gov (United States)

    Thibault, Simon; Parent, Jocelyn; Zhang, Hu; Du, Xiaojun; Roulet, Patrice

    2014-09-01

    In 2014, miniature camera modules are applied to a variety of applications such as webcam, mobile phone, automotive, endoscope, tablets, portable computers and many other products. Mobile phone cameras are probably one of the most challenging parts due to the need for smaller and smaller total track length (TTL) and optimized embedded image processing algorithms. As the technology is developing, higher resolution and higher image quality, new capabilities are required to fulfil the market needs. Consequently, the lens system becomes more complex and requires more optical elements and/or new optical elements. What is the limit? How small an injection molded lens can be? We will discuss those questions by comparing two wide angle lenses for consumer electronic market. The first lens is a 6.56 mm (TTL) panoramic (180° FOV) lens built in 2012. The second is a more recent (2014) panoramic lens (180° FOV) with a TTL of 3.80 mm for mobile phone camera. Both optics are panomorph lenses used with megapixel sensors. Between 2012 and 2014, the development in design and plastic injection molding allowed a reduction of the TTL by more than 40%. This TTL reduction has been achieved by pushing the lens design to the extreme (edge/central air and material thicknesses as well as lens shape). This was also possible due to a better control of the injection molding process and material (low birefringence, haze and thermal stability). These aspects will be presented and discussed. During the next few years, we don't know if new material will come or new process but we will still need innovative people and industries to push again the limits.

  2. Correction of 157-nm lens based on phase ring aberration extraction method

    Science.gov (United States)

    Meute, Jeff; Rich, Georgia K.; Conley, Will; Smith, Bruce W.; Zavyalova, Lena V.; Cashmore, Julian S.; Ashworth, Dominic; Webb, James E.; Rich, Lisa

    2004-05-01

    Early manufacture and use of 157nm high NA lenses has presented significant challenges including: intrinsic birefringence correction, control of optical surface contamination, and the use of relatively unproven materials, coatings, and metrology. Many of these issues were addressed during the manufacture and use of International SEMATECH"s 0.85NA lens. Most significantly, we were the first to employ 157nm phase measurement interferometry (PMI) and birefringence modeling software for lens optimization. These efforts yielded significant wavefront improvement and produced one of the best wavefront-corrected 157nm lenses to date. After applying the best practices to the manufacture of the lens, we still had to overcome the difficulties of integrating the lens into the tool platform at International SEMATECH instead of at the supplier facility. After lens integration, alignment, and field optimization were complete, conventional lithography and phase ring aberration extraction techniques were used to characterize system performance. These techniques suggested a wavefront error of approximately 0.05 waves RMS--much larger than the 0.03 waves RMS predicted by 157nm PMI. In-situ wavefront correction was planned for in the early stages of this project to mitigate risks introduced by the use of development materials and techniques and field integration of the lens. In this publication, we document the development and use of a phase ring aberration extraction method for characterizing imaging performance and a technique for correcting aberrations with the addition of an optical compensation plate. Imaging results before and after the lens correction are presented and differences between actual and predicted results are discussed.

  3. Assessment of the brain’s macro- and microcirculatory blood flow responses to CO2 via transfer function analysis

    Directory of Open Access Journals (Sweden)

    Martin WOlf-DIetrich Müller

    2016-05-01

    Full Text Available Objectives: At present, there is no standard bedside method for assessing cerebral autoregulation (CA with high temporal resolution. We combined the two methods most commonly used for this purpose, transcranial Doppler sonography (TCD, macrocirculation level and near-infrared spectroscopy (NIRS, microcirculation level, in an attempt to identify the most promising approach. Methods: In 8 healthy subjects (5 women; mean age, 38 ± 10 years, CA disturbance was achieved by adding carbon dioxide (CO2 to the breathing air. We simultaneously recorded end-tidal CO2 (ETCO2, blood pressure (BP; non-invasively at the fingertip, and cerebral blood flow velocity (CBFV in both middle cerebral arteries using TCD and determined oxygenated and deoxygenated hemoglobin levels using NIRS. For the analysis, we used transfer function calculations in the low-frequency band (0.07–0.15 Hz to compare BP–CBFV, BP–oxygenated hemoglobin (OxHb, BP–tissue oxygenation index (TOI, CBFV–OxHb, and CBFV–TOI.Results: ETCO2 increased from 37 ± 2 to 44 ± 3 mmHg. The CO2-induced CBFV increase significantly correlated with the OxHb increase (R2 = 0.526, p < 0.001. Compared with baseline, the mean CO2 administration phase shift (in radians significantly increased (p < 0.005 from -0.67 ± 0.20 to -0.51 ± 0.25 in the BP–CBFV system, and decreased from 1.21 ± 0.81 to −0.05 ± 0.91 in the CBFV–OxHb system, and from 0.94 ± 1.22 to −0.24 ± 1.0 in the CBFV–TOI system; no change was observed for BP–OxHb (0.38 ± 1.17 to 0.41 ± 1.42. Gain changed significantly only in the BP–CBFV system. The correlation between the ETCO2 change and phase change was higher in the CBFV–OxHb system [r = −0.60; 95% confidence interval (CI, −0.16, −0.84; p < 0.01] than in the BP–CBFV system (r = 0.52; 95% CI: 0.03, 0.08; p < 0.05.Conclusion: The transfer function characterizes the blood flow transition from macro- to microcirculation by time delay only. The CBFV

  4. 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...

  5. 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 ...

  6. 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...

  7. 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 ...

  8. A determination of H-0 with the class gravitational lens B1608+656. II. Mass models and the Hubble constant from lensing

    NARCIS (Netherlands)

    Koopmans, LVE; Fassnacht, CD

    1999-01-01

    We present mass models of the four-image gravitational lens system B1608 + 656, based on information obtained through VLBA imaging, VLA monitoring, and Hubble Space Telescope (HST) WFPC2 and NICMOS imaging. We have determined a mass model for the lens galaxies that reproduces (1) all image positions

  9. 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.

  10. 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

  11. 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.

  12. 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 ...

  13. 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.

  14. 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

  15. Non-invasive objective and contemporary methods for measuring ocular surface inflammation in soft contact lens wearers - A review.

    Science.gov (United States)

    Chao, Cecilia; Richdale, Kathryn; Jalbert, Isabelle; Doung, Kim; Gokhale, Moneisha

    2017-10-01

    Contact lens wear is one of the primary risk factors for the development of ocular surface inflammatory events. The purpose of this review is to examine and summarize existing knowledge on the mechanisms of contact lens related ocular surface inflammation and the evidence for the effectiveness of current objective methods to measure ocular surface inflammation. Contact lens wear is postulated to trigger an inflammatory response on the ocular surface due to mechanical, chemical, hypoxic stress, or by the introduction of microbes and their toxins. Apart from the traditional signs of inflammation, such as swelling, oedema, redness and heat, on the ocular surface, other methods to measure ocular surface inflammation in sub-clinical levels include tear inflammatory mediator concentrations, conjunctival cell morphology, and corneal epithelial dendritic cell density and morphology. Tear inflammatory mediator concentrations are up- or down-regulated during contact lens wear, with or without the presence of associated inflammatory events. There is higher conjunctival cell metaplasia observed with contact lens wear, but changes in goblet cell density are inconclusive. Dendritic cell density is seen to increase soon after initiating soft contact lens wear. The long term effects of contact lens wear on dendritic cell migration in the cornea and conjunctiva, including the lid wiper area, require further investigation. Currently patient factors, such as age, smoking, systemic diseases and genetic profile are being studied. A better understanding of these mechanisms may facilitate the development of new management options and strategies to minimize ocular surface inflammation related to contact lens wear. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  16. 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.

  17. Radiation exposure to the eye lens of orthopaedic surgeons during various orthopaedic procedures

    International Nuclear Information System (INIS)

    Romanova, K.; Alyakov, M.; Vassileva, J.

    2015-01-01

    The aim of the present study was to assess the radiation dose to the eye lens of orthopaedic surgeons during various orthopaedic procedures and to make efforts to ensure that radiation protection is optimised. The study was performed for Fractura femoris and Fractura cruris procedures performed in orthopaedic operating theatres, as well as for fractures of wrist, ankle and hand/ shoulder performed in the emergency trauma room. The highest mean value of the eye lens dose of 47.2 μSv and higher mean fluoroscopy time of 3 min, as well as the corresponding highest maximum values of 77.1 μSv and 5.0 min were observed for the Fractura femoris procedure performed with the Biplanar 500e fluoroscopy systems. At a normal workload, the estimated mean annual dose values do not exceed the annual occupational dose limit for the lens of eye, but at a heavy workload in the department, this dose limit could be achieved or exceeded. The use of protective lead glasses is recommended as they could reduce the radiation exposure of the lens of the eye. The phantom measurements demonstrated that the use of half-dose mode could additionally reduce dose to the operator's eye lens. (authors)

  18. Optical Tests on a Curve Fresnel Lens as Secondary Optics for Solar Troughs

    Directory of Open Access Journals (Sweden)

    D. Fontani

    2017-01-01

    Full Text Available A curve Fresnel lens is developed as secondary concentrator for solar parabolic troughs to reduce the number of photovoltaic cells. Specific measurements and optical tests are used to evaluate the optical features of manufactured samples. The cylindrical Fresnel lens transforms the focal line, produced by the primary mirror, into a series of focal points. The execution of special laboratory tests on some secondary concentrator samples is discussed in detail, illustrating the methodologies tailored to the specific case. Focusing tests are performed, illuminating different areas of the lens with solar divergence light and acquiring images on the plane of the photocell using a CMOS camera. Concentration measurements are carried out to select the best performing samples of curve Fresnel lens. The insertion of the secondary optics within the concentrating photovoltaic (CPV trough doubles the solar concentration of the system. The mean concentration ratio is 1.73, 2.13, and 2.09 for the three tested lenses. The concentration ratio of the solar trough is 140 and approaches 300 after the introduction of the secondary lens.

  19. A Complex Approach to Noninvasive Estimation of Microcirculatory Tissue Impairments in Feet of Patients with Diabetes Mellitus using Spectroscopy

    Science.gov (United States)

    Potapova, E. V.; Dremin, V. V.; Zherebtsov, E. A.; Makovik, I. N.; Zharkikh, E. V.; Dunaev, A. V.; Pilipenko, O. V.; Sidorov, V. V.; Krupatkin, A. I.

    2017-12-01

    The possibility of a complex approach for studying changes in the system of blood microcirculation and metabolic processes in the biotissue of lower extremities using optical noninvasive methods of laser doppler flowmetry (LDF), fluorescence spectroscopy, and diffuse reflectance spectroscopy in combination with different modes of heating tests has been assessed. Seventy-six patients with type 2 diabetes mellitus, with 14 patients having visible trophic foot impairments, and 48 healthy volunteers have been examined. The parameters of LDF signals and spectra of fluorescence intensity and diffuse reflectance for foot skin have been analyzed. Statistically significant differences in the recorded parameters between the groups under study have been found. It has been concluded that combined application of noninvasive methods of spectroscopy could be used for diagnostics of complications both upon the occurrence of preliminary symptoms of diabetes, when pathological changes are still reversible, and in the presence of impairments to prevent aggravation of the disease and select an adequate correction of the treatment.

  20. 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.

  1. CRITICAL CURVES AND CAUSTICS OF TRIPLE-LENS MODELS

    International Nuclear Information System (INIS)

    Daněk, Kamil; Heyrovský, David

    2015-01-01

    Among the 25 planetary systems detected up to now by gravitational microlensing, there are two cases of a star with two planets, and two cases of a binary star with a planet. Other, yet undetected types of triple lenses include triple stars or stars with a planet with a moon. The analysis and interpretation of such events is hindered by the lack of understanding of essential characteristics of triple lenses, such as their critical curves and caustics. We present here analytical and numerical methods for mapping the critical-curve topology and caustic cusp number in the parameter space of n-point-mass lenses. We apply the methods to the analysis of four symmetric triple-lens models, and obtain altogether 9 different critical-curve topologies and 32 caustic structures. While these results include various generic types, they represent just a subset of all possible triple-lens critical curves and caustics. Using the analyzed models, we demonstrate interesting features of triple lenses that do not occur in two-point-mass lenses. We show an example of a lens that cannot be described by the Chang–Refsdal model in the wide limit. In the close limit we demonstrate unusual structures of primary and secondary caustic loops, and explain the conditions for their occurrence. In the planetary limit we find that the presence of a planet may lead to a whole sequence of additional caustic metamorphoses. We show that a pair of planets may change the structure of the primary caustic even when placed far from their resonant position at the Einstein radius

  2. 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.

  3. Assessment of the Brain's Macro- and Micro-Circulatory Blood Flow Responses to CO2 via Transfer Function Analysis.

    Science.gov (United States)

    Müller, Martin W-D; Österreich, Mareike; Müller, Andreas; Lygeros, John

    2016-01-01

    At present, there is no standard bedside method for assessing cerebral autoregulation (CA) with high temporal resolution. We combined the two methods most commonly used for this purpose, transcranial Doppler sonography (TCD, macro-circulation level), and near-infrared spectroscopy (NIRS, micro-circulation level), in an attempt to identify the most promising approach. In eight healthy subjects (5 women; mean age, 38 ± 10 years), CA disturbance was achieved by adding carbon dioxide (CO2) to the breathing air. We simultaneously recorded end-tidal CO2 (ETCO2), blood pressure (BP; non-invasively at the fingertip), and cerebral blood flow velocity (CBFV) in both middle cerebral arteries using TCD and determined oxygenated and deoxygenated hemoglobin levels using NIRS. For the analysis, we used transfer function calculations in the low-frequency band (0.07-0.15 Hz) to compare BP-CBFV, BP-oxygenated hemoglobin (OxHb), BP-tissue oxygenation index (TOI), CBFV-OxHb, and CBFV-TOI. ETCO2 increased from 37 ± 2 to 44 ± 3 mmHg. The CO2-induced CBFV increase significantly correlated with the OxHb increase (R (2) = 0.526, p macro- to micro-circulation by time delay only. The CBFV-OxHb system response with a broader phase shift distribution offers the prospect of a more detailed grading of CA responses. Whether this is of clinical relevance needs further studies in different patient populations.

  4. Electron Lens Construction for the Integrable Optics Test Accelerator at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    McGee, Mike [Fermilab; Carlson, Kermit [Fermilab; Nobrega, Lucy [Fermilab; Stancari, Giulio [Fermilab; Valishev, Alexander [Fermilab

    2016-06-01

    The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p⁺) diagnostic test ring. Construction of an electron lens for IOTA is necessary for both electron and proton operation. Components required for the Electron Lens design include; a 0.8 T conventional water-cooled main solenoid, and magnetic bending and focusing elements. The foundation of the design relies on repurposing the Fermilab Tevatron Electron Lens II (TELII) gun and collector under ultra-high vacuum (UHV) conditions.

  5. Cellulose nanocrystal and poly[di(ethylene glycol) adipate] blend for tunable lens

    Science.gov (United States)

    Ko, Hyun-U.; Kim, Hyun Chan; Li, Yaguang; Kim, Sang Youn; Kim, Jaehwan

    2016-04-01

    In these days, consumer electronics and medical device for optical diagnosis are minimalized and mobilized. The focusing part is one of crucial parts of optical diagnosis systems to reduce the size and weight. Thus, demand for tunable lens that change the focus itself is increased. To meet the demand, many tunable lens has been studied by utilizing smart materials that responded under mechanical, magnetic, optical, thermal, chemical, electrical or electrochemical stimuli. This paper reports a cellulose nanocrystal (CNC) and poly[di(ethylene glycol) adipate] (PDEGA) blend that is able to respond under electromechanical stimulus. The preparation of CNC/PDEGA and its characterization are illustrated and its actuation behavior is tested . Because the material has high dielectric constant and high reflection index, it is good candidate material for tunable lens.

  6. Development of a Double-Gauss Lens Based Setup for Optoacoustic Applications.

    Science.gov (United States)

    Choi, Hojong; Ryu, Jae-Myung; Yeom, Jung-Yeol

    2017-03-03

    In optoacoustic (photoacoustic) systems, different echo signal intensities such as amplitudes, center frequencies, and bandwidths need to be compensated by utilizing variable gain or time-gain compensation amplifiers. However, such electronic components can increase system complexities and signal noise levels. In this paper, we introduce a double-Gauss lens to generate a large field of view with uniform light intensity due to the low chromatic aberrations of the lens, thus obtaining uniform echo signal intensities across the field of view of the optoacoustic system. In order to validate the uniformity of the echo signal intensities in the system, an in-house transducer was placed at various positions above a tissue sample and echo signals were measured and compared with each other. The custom designed double-Gauss lens demonstrated negligible light intensity variation (±1.5%) across the illumination field of view (~2 cm diameter). When the transducer was used to measure echo signal from an eye of a bigeye tuna within a range of ±1 cm, the peak-to-peak amplitude, center frequency, and their -6 dB bandwidth variations were less than 2 mV, 1 MHz, and 6%, respectively. The custom designed double-Gauss lens can provide uniform light beam across a wide area while generating insignificant echo signal variations, and thus can lower the burden of the receiving electronics or signal processing in the optoacoustic system.

  7. Compositional Dependence Of Hardness Of Ge-Sb-Se Glass For Molded Lens Applications

    Directory of Open Access Journals (Sweden)

    Park J.K.

    2015-06-01

    Full Text Available Chalcogenide glass in the ternary Ge-Sb-Se system is inherently moldable, thus being considered as a strong candidate material for use in infrared-transmitting lens applications from the viewpoint of thermal and mechanical stability. In an effort to experimentally determine compositional region suitable for the molded lens applications, we evaluate its compositional dependence of hardness. Among the constituent atoms, Ge content turns out to exert a most conspicuous correlation with hardness. This phenomenological behavior is then explained in connection with the structural evolution that Ge brings about.

  8. Acanthamoeba Species Keratitis in a Soft Contact Lens Wearer Molecularly Linked to Well Water

    Directory of Open Access Journals (Sweden)

    Samira Mubareka

    2006-01-01

    Full Text Available Acanthamoeba species keratitis has been associated with soft contact lens wear. In the present report, an epidemiological link was established between the patient's isolate and well water from the home using molecular methods. To the authors' knowledge, this is the first case in Canada where such a link has been established. Primary care practitioners and specialists, including ophthalmologists and infectious diseases specialists, must maintain a high degree of clinical suspicion in soft contact lens wearers with keratitis unresponsive to conventional topical and systemic treatment.

  9. 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

  10. THE SLOAN DIGITAL SKY SURVEY QUASAR LENS SEARCH. II. STATISTICAL LENS SAMPLE FROM THETHIRD DATA RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    Inada, N; Oguri, M; Becker, R H; Shin, M; Richards, G T; Hennawi, J F; White, R L; Pindor, B; Strauss, M A; Kochanek, C S; Johnston, D E; Gregg, M D; Kayo, I; Eisenstein, D; Hall, P B; Castander, F J; Clocchiatti, A; Chiu, K; Kawano, Y; Scranton, R; Frieman, J; Keeton, C R; Morokuma, T; Rix, H; Turner, E L; Burless, S; Brunner, R J; Sheldon, E S; Bahcall, N A; Fukugita, M

    2007-09-13

    We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46,420 quasars from the SDSS Data Release 3 ({approx}4188 deg{sup 2}), we select a subsample of 22,683 quasars that are located at redshifts between 0.6 and 2.2 and are brighter than the Galactic extinction corrected i-band magnitude of 19.1. We identify 220 lens candidates from the quasar subsample, for which we conduct extensive and systematic follow-up observations in optical and near-infrared wavebands, in order to construct a complete lensed quasar sample at image separations between 1-inch and 20-inch and flux ratios of faint to bright lensed images larger than 10{sup -0.5}. We construct a statistical sample of 11 lensed quasars. Ten of these are galaxy-scale lenses with small image separations ({approx} 1-inch - 2-inch) and one is a large separation (15-inch) system which is produced by a massive cluster of galaxies, representing the first statistical sample of lensed quasars including both galaxy- and cluster-scale lenses. The Data Release 3 spectroscopic quasars contain an additional 11 lensed quasars outside the statistical sample.

  11. 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.

  12. Informing Automated Writing Evaluation Using the Lens of Genre: Two Studies

    Science.gov (United States)

    Burstein, Jill; Elliot, Norbert; Molloy, Hillary

    2016-01-01

    Genre serves as a useful lens to investigate the range of evidence derived from automated writing evaluation (AWE). To support construct-relevant systems used for writing instruction and assessment, two investigations were conducted that focused on postsecondary writing requirements and faculty perceptions of student writing proficiency. Survey…

  13. Zoom lens designs for use in sheet metal cutting by high power CO2-lasers

    NARCIS (Netherlands)

    Beckmann, L.H.J.F.; Maerten, O.

    1993-01-01

    For best results and the highest speed of cutting sheet metal by high power lasers, the numerical aperture of the focussed beam must be properly matched to the material thickness. To alleviate the need for frequent changes of fixed-focal-length lenses a zoom lens system which allows fast and

  14. Angular and spectral sensitivity of fly photoreceptors. I. Integrated facet lens and rhabdomere optics

    NARCIS (Netherlands)

    Stavenga, D.G.

    Three optical components of a fly’s eye determine the angular sensitivity of the photoreceptors: the light diffracting facet lens, the wave-guiding rhabdomere and the light-absorbing visual pigment in the rhabdomere. How the integrated optical system of the fly eye shapes the angular sensitivity

  15. Approaching Knowledge Management through the Lens of the Knowledge Life Cycle: A Case Study Investigation

    Science.gov (United States)

    Fowlin, Julaine M.; Cennamo, Katherine S.

    2017-01-01

    More organizational leaders are recognizing that their greatest competitive advantage is the knowledge base of their employees and for organizations to thrive knowledge management (KM) systems need to be in place that encourage the natural interplay and flow of tacit and explicit knowledge. Approaching KM through the lens of the knowledge life…

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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. ...

  1. 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

  2. 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

  3. [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.

  4. 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.

  5. 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)

  6. 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

  7. 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.

  8. 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...

  9. Bilateral posterior crystalline lens dislocations in an otherwise healthy child

    Directory of Open Access Journals (Sweden)

    AlShehri, Omar A.

    2017-10-01

    Full Text Available Introduction: Ectopia lentis is defined as a crystalline lens displacement, either partially or completely, due to zonular abnormalities. It can be a result of trauma, hereditary ocular disease, or part of systemic diseases, like Marfan syndrome and homocystinuria.Case description: We report a case of a medically free 16-year-old girl, who was referred to our hospital complaining of poor vision and a squint in both eyes since childhood. Her history included a traffic accident when she was one-year-old. She was previously diagnosed with alternating esotropia, which was treated with glasses, alternating patching, and bilateral Botox injections. On examination, she had a visual acuity of 6/7.5 with correction in the right eye and 6/6 with correction in the left eye. She had an esotropia of 60 prism diopters, which was partially corrected to 40 prism diopters for near and distance vision. Fundus examination showed myopic changes in each eye and dislocated lenses in the posterior pole at 6 o’clock. Our case was stable, so we used conservative management with contact lenses.Conclusion: Bilateral posterior lens dislocation is very rare. A proper examination is important and early diagnosis can prevent serious complications, such as retinal detachment or pupillary block glaucoma.

  10. Optical quality of toric intraocular lens implantation in cataract surgery

    Directory of Open Access Journals (Sweden)

    Xian-Wen Xiao

    2015-02-01

    Full Text Available AIM: To analyze the optical quality after implantation of toric intraocular lens with optical quality analysis system. METHODS: Fifty-two eyes of forty-four patients with regular corneal astigmatism of at least 1.00 D underwent implantation of AcrySof toric intraocular lens, including T3 group 19 eyes, T4 group 18 eyes, T5 group 10 eyes, T6 group 5 eyes. Main outcomes evaluated at 3mo of follow-up, included uncorrected distance visual acuity (UDVA, corrected distance visual acuity (CDVA, residual refractive cylinder and intraocular lens (IOL axis rotation. Objective optical quality were measured using optical quality analysis system (OQAS Ⅱ®, Visiometrics, Spain, included the cutoff frequency of modulation transfer function (MTFcutoff, objective scattering index (OSI, Strehl ratio, optical quality analysis system value (OV 100%, OV 20% and OV 9% [the optical quality analysis system (OQAS values at contrasts of 100%, 20%, and 9%]. RESULTS: At 3mo postoperative, the mean UDVA and CDVA was 0.18±0.11 and 0.07±0.08 logMAR; the mean residual refractive cylinder was 0.50±0.29 D; the mean toric IOL axis rotation was 3.62±1.76 degrees, the mean MTFcutoff, OSI, Strehl ratio, OV 100%, OV 20% and OV 9% were 22.862±5.584, 1.80±0.84, 0.155±0.038, 0.76±0.18, 0.77±0.19 and 0.78±0.21. The values of UDVA, CDVA, IOL axis rotation, MTFcutoff, OSI, Strehl ratio, OV100%, OV20% and OV9% depending on the power of the cylinder of the implantation were not significantly different (P>0.05, except the residual refractive cylinder (PCONCLUSION: The optical quality analysis system was useful for characterizing the optical quality of AcrySof toric IOL implantation. Implantation of an AcrySof toric IOL is an effective and safe method to correct corneal astigmatism during cataract surgery.

  11. 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

  12. High-Resolution UV Relay Lens for Particle Size Distribution Measurements Using Holography

    International Nuclear Information System (INIS)

    Robert M. Malone, Brent C. Frogget, Morris I. Kaufman, Aric Tibbits, Gene A. Capelle, Mike Grover, Gerald D. Stevens, William D. Turley

    2008-01-01

    Shock waves passing through a metal sample can produce ejecta particulates at a metal-vacuum interface. Holography records particle size distributions by using a highpower, short-pulse laser to freeze particle motion. The sizes of the ejecta particles are recorded using an in-line Fraunhofer holography technique. Because the holographic plate would be destroyed in this energetic environment, a high-resolution lens has been designed to relay the interference fringes to a safe environment. Particle sizes within a 12-mm-diameter, 5-mm-thick volume are recorded on holographic film. To achieve resolution down to 0.5 microns, ultraviolet (UV) light (in this case supplied by a tripled Nd:YAG laser) is needed. The design and assembly of a nine-element lens that achieves >2000 lp/mm resolution and operates at f/0.85 will be described. To set up this lens system, a doublet lens is temporarily attached that enables operation with 532-nm (green) light and 1100 lp/mm resolution. Thus, the setup and alignment is performed with green light, but the dynamic recording is done with UV light. During setup, the 532-nm beam provides enough focus shift to accommodate the placement of a resolution pattern outside the ejecta volume; this resolution pattern does not interfere with the calibrated wires and pegs surrounding the ejecta volume. A television microscope archives images of resolution patterns that prove that the calibration wires, interference filter, holographic plate, and relay lenses are in their correct positions. Part of this lens is under vacuum, at the point where the laser illumination passes through a focus. Alignment and tolerancing of this high-resolution lens will be presented, and resolution variation through the 5-mm depth of field will be discussed

  13. DNA damage in lens epithelium of cataract patients in vivo and ex vivo.

    Science.gov (United States)

    Øsnes-Ringen, Oyvind; Azqueta, Amaia O; Moe, Morten C; Zetterström, Charlotta; Røger, Magnus; Nicolaissen, Bjørn; Collins, Andrew R

    2013-11-01

    DNA damage has been described in the human cataractous lens epithelium, and oxidative stress generated by UV radiation and endogenous metabolic processes has been suggested to play a significant role in the pathogenesis of cataract. In this study, the aim was to explore the quality and relative quantity of DNA damage in lens epithelium of cataract patients in vivo and after incubation in a cell culture system. Capsulotomy specimens were analysed, before and after 1 week of ex vivo cultivation, using the comet assay to measure DNA strand breaks, oxidized purine and pyrimidine bases and UV-induced cyclobutane pyrimidine dimers. DNA strand breaks were barely detectable, oxidized pyrimidines and pyrimidine dimers were present at low levels, whereas there was a relatively high level of oxidized purines, which further increased after cultivation. The observed levels of oxidized purines in cataractous lens epithelium may support a theory consistent with light damage and oxidative stress as mediators of molecular damage to the human lens epithelium. Damage commonly associated with UV-B irradiation was relatively low. The levels of oxidized purines increased further in a commonly used culture system. This is of interest considering the importance and versatility of ex vivo systems in studies exploring the pathogenesis of cataract. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

  14. Thermomechanical Assessment of the Collector for the Hollow Electron Lens

    CERN Document Server

    Anderson, George Bowers

    2017-01-01

    The hollow electron lens (HEL) is a system proposed for the High Luminosity upgrade of the Large Hadron Collider LHC (HL-LHC) [1]. Being considered for installation at LHC point 4, the HEL improves halo control and collimation of proton beams in the collider [2]. This is achieved by creating a hollow tube of electrons using an electron gun. This axisymmetric electron cloud travels around the proton beam for a few meters, overlapping with the proton beam halo, until the electron cloud is dissipated in a collector, which is the focus of this project. A 3D image of the HEL system is found in Figure 1 and a further technical description of such electron lenses is available in [3].

  15. Exploiting the dispersion of the double-negative-index fishnet metamaterial to create a broadband low-profile metallic lens.

    Science.gov (United States)

    Orazbayev, B; Pacheco-Peña, V; Beruete, M; Navarro-Cía, M

    2015-04-06

    Metamaterial lenses with close values of permittivity and permeability usually display low reflection losses at the expense of narrow single frequency operation. Here, a broadband low-profile lens is designed by exploiting the dispersion of a fishnet metamaterial together with the zoning technique. The lens operates in a broadband regime from 54 GHz to 58 GHz, representing a fractional bandwidth ~7%, and outperforms Silicon lenses between 54 and 55.5 GHz. This broadband operation is demonstrated by a systematic analysis comprising Huygens-Fresnel analytical method, full-wave numerical simulations and experimental measurements at millimeter waves. For demonstrative purposes, a detailed study of the lens operation at two frequencies is done for the most important lens parameters (focal length, depth of focus, resolution, radiation diagram). Experimental results demonstrate diffraction-limited ~0.5λ transverse resolution, in agreement with analytical and numerical calculations. In a lens antenna configuration, a directivity as high as 16.6 dBi is achieved. The different focal lengths implemented into a single lens could be potentially used for realizing the front end of a non-mechanical zoom millimeter-wave imaging system.

  16. Camera, handlens, and microscope optical system for imaging and coupled optical spectroscopy

    Science.gov (United States)

    Mungas, Greg S. (Inventor); Boynton, John (Inventor); Sepulveda, Cesar A. (Inventor); Nunes de Sepulveda, legal representative, Alicia (Inventor); Gursel, Yekta (Inventor)

    2012-01-01

    An optical system comprising two lens cells, each lens cell comprising multiple lens elements, to provide imaging over a very wide image distance and within a wide range of magnification by changing the distance between the two lens cells. An embodiment also provides scannable laser spectroscopic measurements within the field-of-view of the instrument.

  17. 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)

  18. APPROACH TO AUTOMATION OF LENS COMPONENTS CENTERING FOR ASSEMBLING OF DIFFERENT DESIGN OBJECTIVES

    Directory of Open Access Journals (Sweden)

    A. Y. Pimenov

    2016-01-01

    Full Text Available Subject of Research.Existing adjustment methods of lens objectives in two mechanical designs have been analyzed, the main ways of centering error compensation have been considered. The algorithm of automated search of optical elements position has been developed based on the existing methods of centering for compensation of residual decentering. The methods of joint application of this algorithm and centering machine “Trioptics Opticentric” have been suggested. Method. Centering errors of the objective lens components are measured on the centering machine. Aberrations of optical system are calculated by using the received data of centering errors entered to the objective mathematical model. For the calculation of aberration compensation, iteration algorithm of searching of optical elements optimal position is used. The image quality is analyzed for each obtained realization of the optical system. The result of program performance is data matrix about optical components location such that compensation of residual aberrations occurs. Based on the obtained information the system assembling is carried out with the use of centering machine “Trioptics Opticentric”. Main Results. Computer modeling of centering errors for 100 lens apochromatic objectives of drop-in mountings lens design has been carried out. The coma of object axial point image has been chosen as quality estimation criterion. The developed algorithm has been applied for the worst realization of the optical system. In this case the value of integral coma of object axial point image has been decreased by two orders and reduced practically to zero. It is noted that the modeling of adjustment process via using the algorithm of automated search enables to predict the possibility of objective assembly with required quality parameters. Practical Relevance. The received results can be applied on the lines of automated assembly of modern lens objectives.

  19. 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.

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

    Science.gov (United States)

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

    2012-01-01

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

  1. The Sloan Lens ACS Survey. XIII. Discovery of 40 New Galaxy-scale Strong Lenses

    Science.gov (United States)

    Shu, Yiping; Brownstein, Joel R.; Bolton, Adam S.; Koopmans, Léon V. E.; Treu, Tommaso; Montero-Dorta, Antonio D.; Auger, Matthew W.; Czoske, Oliver; Gavazzi, Raphaël; Marshall, Philip J.; Moustakas, Leonidas A.

    2017-12-01

    We present the full sample of 118 galaxy-scale strong-lens candidates in the Sloan Lens ACS (SLACS) Survey for the Masses (S4TM) Survey, which are spectroscopically selected from the final data release of the Sloan Digital Sky Survey. Follow-up Hubble Space Telescope (HST) imaging observations confirm that 40 candidates are definite strong lenses with multiple lensed images. The foreground-lens galaxies are found to be early-type galaxies (ETGs) at redshifts 0.06–0.44, and background sources are emission-line galaxies at redshifts 0.22–1.29. As an extension of the SLACS Survey, the S4TM Survey is the first attempt to preferentially search for strong-lens systems with relatively lower lens masses than those in the pre-existing strong-lens samples. By fitting HST data with a singular isothermal ellipsoid model, we find that the total projected mass within the Einstein radius of the S4TM strong-lens sample ranges from 3 × 1010 M ⊙ to 2 × 1011 M ⊙. In Shu et al., we have derived the total stellar mass of the S4TM lenses to be 5 × 1010 M ⊙ to 1 × 1012 M ⊙. Both the total enclosed mass and stellar mass of the S4TM lenses are on average almost a factor of 2 smaller than those of the SLACS lenses, which also represent the typical mass scales of the current strong-lens samples. The extended mass coverage provided by the S4TM sample can enable a direct test, with the aid of strong lensing, for transitions in scaling relations, kinematic properties, mass structure, and dark-matter content trends of ETGs at intermediate-mass scales as noted in previous studies. Based on observations made with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. These observations are associated with HST program #12210.

  2. Pilot study of the dose in crystalline lens in the interventional radiology practice

    International Nuclear Information System (INIS)

    Castro, A.; Martinez, A.; Fernandez, A.; Molina, D.; Sanchez, L.; Diaz, A.

    2014-08-01

    Hp(10) and dosimeters for crystalline lens with three detectors of the same material to evaluate the personal equivalent dose Hp(3). The selected detectors were previously subjected to tests recommended by the standard IEC-61066 and segregated by their individual sensibility. For the reading dosimeters was used the automatic system TLD RADOS model of the Laboratorio de Dosimetria Externa del Centro de Proteccion e Higiene de las Radiaciones, calibrated in function of the magnitude to evaluate. This study allowed demonstrating that the application of the new established dose limit for crystalline lens can result in different implications from the operational view point in the radiological surveillance programs. Also it facilitated the diffusion of some recommendations regarding type of singular radiological surveillance and use frequency for the OEP during the interventional procedures. (author)

  3. Strategies for the prevention of contact lens-related Acanthamoeba keratitis: a review.

    Science.gov (United States)

    Carnt, Nicole; Stapleton, Fiona

    2016-03-01

    Acanthamoeba keratitis is a severe, often sight threatening, corneal infection which in Western countries is predominantly seen in daily wear of contact lenses. This review aims to summarise the pathobiology and epidemiology of contact lens-related Acanthamoeba keratitis, and to present strategies for prevention, particularly with respect to modifiable risk factors in contact lens wear. The virulence of Acanthamoeba and resistance to treatment in keratitis appears to be linked with the production of a low molecular weight protease MIP133 by the organism, in response to binding to corneal epithelial cells through a mannose binding protein, and to the ability of the organism to convert from the trophozoite to the resistant cyst form. Recent epidemiological studies in contact lens relate disease have confirmed the link between solution topping up and Acanthamoeba keratitis and have reinforced the importance of avoidance of tap water, either as part of the care for the contact lens or storage case, handling lenses with wet hands or showering while wearing lenses. In the most recent analysis from the USA, there were no strong effects for solution type, water source or water disinfection process. Wearer age, lens wear time and history to appear to be linked with Acanthamoeba keratitis. Daily disposable contact lens use would be expected to reduce the prevalence of Acanthamoeba disease although this is unproven. While Acanthamoeba keratitis remains challenging to diagnose and manage, strategies to limit the disease severity in contact lens wearers should include attention to recently identified risk factors, particularly those related to water contact. Public health awareness measures, the use of daily disposable contact lenses, a better understanding of the contribution of the host immunity and the development of standardised methods for culture of amoeba and testing of contact lens care systems against Acanthamoeba in the licensing process may be of value. Alternative

  4. A planar-dimensions machine vision measurement method based on lens distortion correction.

    Science.gov (United States)

    Sun, Qiucheng; Hou, Yueqian; Tan, Qingchang; Li, Guannan

    2013-01-01

    Lens distortion practically presents in a real optical imaging system causing nonuniform geometric distortion in the images and gives rise to additional errors in the vision measurement. In this paper, a planar-dimensions vision measurement method is proposed by improving camera calibration, in which the lens distortion is corrected on the pixel plane of image. The method can be divided into three steps: firstly, the feature points, only in the small central region of the image, are used to get a more accurate perspective projection model; secondly, rather than defining a uniform model, the smoothing spline function is used to describe the lens distortion in the measurement region of image, and two correction functions can be obtained by fitting two deviation surfaces; finally, a measurement method for planar dimensions is proposed, in which accurate magnification factor of imaging system can be obtained by using the correction functions. The effectiveness of the method is demonstrated by applying the proposed method to the test of measuring shaft diameter. Experimental data prove that the accurate planar-dimensions measurements can be performed using the proposed method even if images are deformed by lens distortion.

  5. 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.

  6. Flow observation by rod lens and low-light video (videotape script: January 4, 1977)

    International Nuclear Information System (INIS)

    Lord, D.E.; Carter, G.W.; Petrini, R.R.

    1977-01-01

    The script of a demonstration videotape made to show the possibilities of coupling rod lenses to low-light video systems to observe internal flow conditions is presented. The illustrations accompanying the text were photographed directly from the video screen. Some up-dated comments appear as footnotes to the original script and a description of the multiscan low-light television system developed to measure velocity is included in the epilogue. The combination of rod lens and low-light video system makes it possible to observe dynamic events in hitherto inaccessible volumes. The pressure and temperature capabilities of the rod lens make it applicable to many engineering uses. This system, in conjunction with electronic image enhancement systems, provides a new dimension in engineering analysis

  7. Flow observation by rod lens and low-light video (videotape script: January 4, 1977)

    Energy Technology Data Exchange (ETDEWEB)

    Lord, D.E.; Carter, G.W.; Petrini, R.R.

    1977-08-10

    The script of a demonstration videotape made to show the possibilities of coupling rod lenses to low-light video systems to observe internal flow conditions is presented. The illustrations accompanying the text were photographed directly from the video screen. Some up-dated comments appear as footnotes to the original script and a description of the multiscan low-light television system developed to measure velocity is included in the epilogue. The combination of rod lens and low-light video system makes it possible to observe dynamic events in hitherto inaccessible volumes. The pressure and temperature capabilities of the rod lens make it applicable to many engineering uses. This system, in conjunction with electronic image enhancement systems, provides a new dimension in engineering analysis.

  8. 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 ...

  9. 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

  10. 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...

  11. 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...

  12. 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.

  13. 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.

  14. [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.

  15. 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.

  16. Effects of the 1998 Drought on the Freshwater Lens in the Laura Area, Majuro Atoll, Republic of the Marshall Islands

    Science.gov (United States)

    Presley, Todd K.

    2005-01-01

    Lower than average rainfall during late 1997 and early 1998 in Majuro Atoll, Republic of the Marshall Islands, caused a drought and severe drinking-water shortage. Majuro depends on a public rainfall catchment system, which uses an airport runway and storage reservoirs. The storage reservoirs can supply water for about 30 to 50 days without replenishment. In February 1998, after a few months with less than one inch of rainfall per month, a drought-related disaster was declared. Reverse-osmosis water-purification systems were brought to Majuro to help alleviate the water shortage. Concurrent with the water-purification program, ground water from a freshwater lens in the Laura area of the atoll was pumped at increased rates. Of the total consumed water during this period, ground water from Laura supplied between 90 percent (March 1998) and 64 percent (May 1998) of the drinking water. Due to public concern, a study was initiated to determine the effects of the drought on the freshwater lens. The areal extent of the freshwater lens is about 350 acres. A monitoring-well network, consisting of multiple wells driven to varying depths at 11 sites, was installed to determine the thickness of the freshwater lens. Similar locations relative to an earlier study were chosen so that the data from this study could be compared to 1984-85 data. At the end of the drought in June 1998, the freshwater near the middle of the lens was about 45 feet thick; and at the north and south ends, the freshwater was about 25 to 38 feet thick, respectively. Monitoring of the freshwater lens was continued through the wet season following the drought. The lens increased in thickness by 1 to 8 feet after 7 months of rainfall. Greater increases in lens thickness were measured on the lagoon side than on the ocean side of the freshwater lens. Lens thickness during August 1998, and seasonal variation of lens thickness in 1998, were compared to data collected in 1984-85. Comparison of lens thickness from

  17. 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...

  18. 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

  19. [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.

  20. 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