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Sample records for clear lens extraction

  1. Assessment of phacoaspiration techniques in clear lens extraction for correction of high myopia

    OpenAIRE

    El-Helw, Mostafa

    2010-01-01

    Mostafa A El-Helw, Ahmed M EmarahDepartment of Ophthalmology, Cairo University, EgyptPurpose: To evaluate various phacoaspiration techniques in clear lens extraction for the incidence of intraoperative difficulties and complications.Patients and methods: This was a prospective study in which bilateral clear lens extraction was performed on 40 eyes of 20 patients, to correct high myopia. The patients were divided into 2 groups: group A underwent supracapsular phacoaspiration; group B were the ...

  2. Assessment of phacoaspiration techniques in clear lens extraction for correction of high myopia

    Directory of Open Access Journals (Sweden)

    Mostafa A El-Helw

    2010-03-01

    Full Text Available Mostafa A El-Helw, Ahmed M EmarahDepartment of Ophthalmology, Cairo University, EgyptPurpose: To evaluate various phacoaspiration techniques in clear lens extraction for the incidence of intraoperative difficulties and complications.Patients and methods: This was a prospective study in which bilateral clear lens extraction was performed on 40 eyes of 20 patients, to correct high myopia. The patients were divided into 2 groups: group A underwent supracapsular phacoaspiration; group B were the contralateral eyes of the same patient. These patients were operated on with endocapsular phacoaspiration with the divide and conquer (D and C technique. Preoperative ocular examination data were recorded and tested for significance. Intraoperative difficulties and complications such as nucleus cracking, capsule rupture and vitreous loss, and repeated chamber collapse were recorded. Postoperative examination data were recorded.Results: Mean age was 35.65 ± 5.85 years. Mean follow-up time was 17.1 ± 8.56 months. In group A mean myopia was -17.3 ± 5.07 diopters; in group B myopia was -17.9 ± 4.20 diopters. Mean preoperative uncorrected visual acuity (UCVA was 0.04 ± 0.0167, while the mean postoperative UCVA was 0.435 ± 0.1442. There was a significant difference in pre and postoperative BCVA within both groups, but not between the two groups. In both groups endothelial cell count (ECC showed a significant difference between pre- and postoperative data; however, there was no statistically significant difference between both groups in postoperative ECC. The effective phacoaspiration time for group A was 4.6 ± 1.6 seconds, and for group B 9.90 ± 2.27 seconds (P < 0.005. No cases of capsule rupture occurred in group A, but 3 cases occurred in group B (15 % (not significant, P = 0.231. Nucleus cracking did not occur in group A, but in group B 13 cases occurred (65%. Chamber collapse occurred in 4 cases (20% in group A and 5 cases (25% in group B (not

  3. Extração do cristalino translúcido: resultados visuais e freqüência de vítreo-retinopatias Clear lens extraction: visual outcomes and vitreoretinopathy frequence

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    João Arraes

    2006-10-01

    underwent clear lens extraction (CLE to correct myopia. METHODS: Thirty-five patients (60 eyes that underwent clear lens extraction at the "Fundação Altino Ventura" had median follow-up of 20.5 months. They were classified into 3 groups: Group I that was submitted to preoperative 360° preequatorial retinal photocoagulation; Group II that was submitted to prophylactic photocoagulation around predisposing lesions; and Group III that was not submitted to preoperative retinal photocoagulation. The presence of corrected visual acuity (CVA, refractional spherical equivalent (RSE and choroidal neovascularization (CNV, predisposing lesions and retinal detachment (RD was evaluated. RESULTS: Median corrected visual acuity value rose from 0.2 in the preoperative period to 0.5 in the postoperative period and refractional spherical equivalent decreased from -17SD to -1.7SD. There was no retinal detachment, but vitreous retinal traction areas appeared in 4 eyes (2 submitted to 360° laser and 2 not submitted to laser and 1 case of choroidal neovascularization also occurred. CONCLUSIONS: Clear lens extraction was an effective and predictable surgery to reduce myopias and an apparently safe procedure in patients with and without prophylactic preequatorial retinal photocoagulation. A longer follow-up in a larger group may validate its safety as a refractive surgery.

  4. Change in Astigmatism After Temporal Clear Corneal Cataract Extraction in the Pediatric Population

    OpenAIRE

    Lam, Helene Y; Yen, Kimberly G

    2008-01-01

    Purpose: To evaluate the early postoperative change in astigmatism in pediatric patients having cataract extraction with intraocular lens implantation using sutured temporal clear corneal incision. Methods: A retrospective chart review was performed on all pediatric patients who underwent clear corneal cataract surgery with intraocular lens implantation between 12/01/2005 and 11/30/2006. Results: A total of 31 eyes of 22 patients who underwent temporal clear corneal cataract surgery and intra...

  5. Effect on contrast sensitivity after clear, yellow and orange intraocular lens implantation.

    Science.gov (United States)

    Bandyopadhyay, Sabyasachi; Saha, Mita; Chakrabarti, Asim; Sinha, Abhik

    2016-06-01

    The objective of this study is to evaluate contrast sensitivity function (CSF) after clear, yellow- and orange-tinted intraocular lens (IOL) implantation. This was a prospective randomized study of 98 patients with senile cataract for a period of 6 months from day 1 of August 2014 to day 31 of January 2015. After phacoemulsification, 33 patients were implanted with clear IOLs (AcrySof UV-filtering IOL, SA60AT), 32 patients were implanted with yellow coloured IOLs (AcrySof Natural blue-light-attenuating and UV-filtering IOL, SN60AT with IMPRUV(®) filter) and 33 patients were implanted with orange-tinted blue-filtering IOLs (PC440Y Optech). After 1 month, monocular CSF was done under photopic (85 cd/m(2)) and mesopic (3 cd/m(2)) illumination condition with CSV-1000 test. The best corrected visual acuity (BCVA) after 1 month was 0.021 ± 0.058 logMAR for clear lens, 0.022 ± 0.059 logMAR for yellow lens and 0.019 ± 0.065 logMAR for orange lens (p = 0.989). Uniocular average photopic contrast sensitivity was 1.36 ± 0.19, 1.43 ± 0.18 and 1.46 ± 0.15 log units for clear lens, yellow lens and orange lens, respectively (statistically not significant; p = 0.076). Average mesopic contrast sensitivity was 1.02 ± 0.21 log units for clear lens, 1.00 ± 0.17 log units for yellow lens and 0.99 ± 0.15 log units for orange lens (statistically not significant; p = 0.771). Yellow or orange coloured blue-filtering IOLs are comparable to clear IOLs in terms of photopic and mesopic contrast sensitivity. PMID:26286756

  6. Clear lens phacoemulsification in the anterior lenticonus due to Alport Syndrome: two case reports

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    Aslanzadeh Ghassem

    2008-05-01

    Full Text Available Abstract Introduction Alport Syndrome has a prevalence of 1 case per 5,000 people and 85% of patients have the X-linked form, where affected males develop renal failure and usually have high-tone sensorineural deafness by age 20. The main abnormality is deficient synthesis of type IV collagen, the main component of basement membranes. Common ocular abnormalities of this syndrome consist of dot-and-fleck retinopathy, posterior polymorphous corneal dystrophy, and anterior lenticonus, but other ocular defects such as cataracts, posterior lenticonus, and retinal detachments have also been reported. Case presentation We report two cases of anterior lenticonus due to Alport Syndrome and describe clear lens phacoemulsification and foldable intraocular lens implantation as an effective and safe refractive procedure in the four eyes of these two patients. Conclusion All four eyes of the two patients were in good condition after surgery and achieved satisfactory optical and visual results and had no remarkable complications at six-months follow-up. Clear lens phacoemulsification with foldable intraocular lens implantation can be used as an efficient and safe procedure for vision disorders in these patients.

  7. Primary lens extraction for glaucoma management: A review article

    OpenAIRE

    Eid, Tarek M.

    2011-01-01

    Recently, primary lens extraction alone gained more acceptance as an alternative surgical approach for glaucoma management. This view was supported by the advances in phacoemulsification and intraocular lenses with greater safety and visual recovery, in addition to a substantial reduction of intraocular pressure and deepening of the anterior chamber and filtration angle. The decrease in IOP after cataract surgery in primary open-angle glaucoma (POAG) is mild, less predictable, related to base...

  8. Clinically unsuspected phacoanaphylaxis after extracapsular cataract extraction with intraocular lens implantation.

    OpenAIRE

    McMahon, M S; Weiss, J S; Riedel, K G; Albert, D. M.

    1985-01-01

    We describe the histopathological findings of an enucleation specimen from a clinically undiagnosed case of phacoanaphylaxis which occurred after extracapsular cataract extraction with intraocular lens implantation. Phacoanaphylaxis, a granulomatous inflammatory response to liberated lens protein, is potentially curable by prompt removal of residual lens material. This case emphasises that the diagnosis of phacoanaphylactic endophthalmitis should be considered in any case of extracapsular cat...

  9. Extracapsular cataract extraction : the fate of retained lens material and intraocular lenses

    OpenAIRE

    Kappelhof, Johan

    1987-01-01

    textabstractThe aim of this study was to examine the fate of the lens material that remains in the eye after an extracapsular cataract extraction both with and without insertion of an intraocular lens. Apart from this, the development of precipitates on the intraocular lenses was morphologically investigated in order to get a better understanding of the interactions between eye and intraocular lens. This thesis is divided into a first part covering animal experiments and a second part about m...

  10. Dipole magnet and quadrupole lens for the slow extraction of a beam from the Dubna synchrophasotron

    International Nuclear Information System (INIS)

    The deflection system for the second slow extraction (SE-2) of a beam of protons and nuclei from the Dubna synchrophasotron consists of a dipole septum-magnet (VM-2) and a quadrupole septum-lens (VL-2). The magnet, the lens, the current conductors for supplying their windings and the driver used for the SE-2 system are described. A general scheme of cooling the windings of the magnet, lens and conductors is presented. The magnetic characteristics of the VM-2 magnet and the VL-2 lens are given. The system used to control the parameters of the SE-2 is described. 4 refs.; 16 figs

  11. Anterior Crossbite and Crowding Correction with a Series of Clear Aligners Involving Lower Incisor Extraction: "The Clear Way" Case Report.

    Science.gov (United States)

    Bawaskar, Naval Suresh

    2015-01-01

    The Clear Aligner can be used to correct tooth movement without involving extraction, surgery, and other adjunct orthopaedic appliances. Some forms ofattachments are required with clear aligners to achieve all major types of orthodontic tooth movements. The Clear Aligner is a procedure that can be performed by a clinician with computer simulation/calculation. Since the Clear Aligner can be fabricated in steps, it is readily available to change the treatment sequence throughout the course of the treatment in cases of complex malocclusions. The patient can receive any necessary dental procedures with ease during the course of the treatment. The treatment can also be easily resumed even if the patient has not worn the aligners for a period of time. The purpose of this article is to report dental anterior crossbite correction with a series of Clear Aligners without the use of any forms of attachments. The Clear Aligner could be used as an alternative in appropriate cases for those who are reluctant with conventional appliances. PMID:27029089

  12. Cataract extraction and lens implantation with and without trabeculectomy: an intrapatient comparison.

    OpenAIRE

    Bobrow, J C

    1998-01-01

    OBJECTIVE: To determine whether cataract extraction and lens implantation combined with trabeculectomy provides better long-term results than cataract extraction and lens implantation alone in a group of patients with primary open-angle glaucoma and cataract randomly selected to receive surgery with trabeculectomy in one eye and without in the other. METHODS: A prospective, randomized clinical trial involving 35 patients with bilateral symmetric primary open-angle glaucoma and visually disabl...

  13. Phacolytic glaucoma-its treatment by planned extracapsular cataract extraction with posterior chamber intraocular lens implantation

    OpenAIRE

    Singh Gurdeep; Kaur Jagmeet; Mall Sanjay

    1994-01-01

    Phacolytic glaucoma has traditionally been treated with intracapsular lens extraction to avoid any anaphylaxis. Various mechanisms have been described for the rise of intraocular pressure in these cases. The present study was undertaken to evaluate the response of extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens implantation (PC IOL) in five cases of phacolytic glaucoma that occurred between March 1989 and August 1990. A planned extracapsular cataract extractio...

  14. Inflammation after cataract extraction and intraocular lens implantation in patients with rheumatoid arthritis.

    OpenAIRE

    Matsuo, T; Fujiwara, M.; Matsuo, N

    1995-01-01

    AIMS--The purpose of this study was to examine whether preoperative activity of rheumatoid arthritis influences the extent of anterior chamber inflammation after cataract extraction and intraocular lens implantation. METHODS--The medical records of 23 consecutive patients (33 eyes) with rheumatoid arthritis, who underwent cataract extraction with intraocular lens implantation, were reviewed during a 4 year period from April 1990 to March 1994. RESULTS--Eleven patients who still showed a 1+ le...

  15. Eyeglasses lens contour extraction from facial images using an efficient shape description.

    Science.gov (United States)

    Borza, Diana; Darabant, Adrian Sergiu; Danescu, Radu

    2013-01-01

    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. PMID:24152926

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

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    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.

  17. Treatment of ophidism-induced bilateral canine cataract by extracapsular lens extraction and intraocular lens implantation.

    Science.gov (United States)

    Kibar, M; Evereklioğlu, C; Doğan, Z

    2014-01-01

    The aim of this study was to report a new cause of cataract, namely snake bite induced cataract in a dog. A 3-year-old male mongrel dog was referred to our clinic for the assessment of cataract in both eyes. The dog was bitten by a snake nearly 4 months ago. A 40 dioptre acrylic lens with 13 mm haptics was implanted into the lens capsule. In the left eye, posterior synechia was detected in the temporal part of the iris, but decentration of the intraocular lens was not observed. To the best of our knowledge, this is the first report of bilateral cataract caused by ophidism and treated by surgical intervention in a dog. PMID:27175143

  18. Audit of outcome of an extracapsular cataract extraction and posterior chamber intraocular lens training course

    OpenAIRE

    Alhassan, M; Kyari, F.; Achi, I.; Ozemela, C.; Abiose, A

    2000-01-01

    BACKGROUND—A training course for cataract surgery with intraocular lens implantation was organised in April 1997 at the National Eye Centre, Kaduna, Nigeria. Operations were performed by six Nigerian consultant ophthalmologists under the supervision of two surgeons from Aravind Eye Hospital, India.
METHODS—A total of 175 eyes with uncomplicated cataracts were operated on after careful selection. All but six patients had extracapsular cataract extraction with posterior chamber intraocular lens...

  19. Quadrupole lens and extraction magnets of a compact race-track microtron

    OpenAIRE

    Vladimirov, Ivan; Pakhomov, Nikolai; Shvedunov, Vasiliy; Koubychine Merkulov, Youri Alexandrovich; Rigla Perez, Juan Pablo; Zakharov, Vitaliy

    2014-01-01

    The compact race-track microtron (RTM) with a maximum energy of 12 MeV that is under construction at the Technical University of Catalonia consists of a quadrupole lens for horizontal focusing of the beam and four dipole magnets for the extraction of the beam from the accelerator. The source of the magnetic field in the magnets is a rare-earth permanent magnet (REPM). The main characteristics of the quadrupole lens and the extraction magnets and the procedure for the tuning of their ...

  20. Extracapsular cataract extraction with posterior chamber lens implantation in Fuch's heterochromic cyclitis.

    OpenAIRE

    Baarsma, G.S.; Vries, J. de; Hammudoglu, C. D.

    1991-01-01

    Twenty-two patients with Fuch's heterochromic cyclitis had a posterior chamber intraocular lens implanted after extracapsular cataract extraction. After a mean follow-up period of 2.5 years (range, 6 to 70 months) half the patients had a visual acuity of 1.0 or more. The results compare favourably with those in the general population.

  1. Idiopathic pupillary capture 7 years after extracapsular cataract extraction and intraocular lens implantation

    OpenAIRE

    Ramos, Juan; Jurado, Venancio

    2011-01-01

    Pupillary capture is a pathology commonly associated with traumatic or inflammatory processes of the eye. We present a case of idiopathic pupillary capture, 7 years after extracapsular cataract extraction and intraocular lens implantation. This case highlights the need for ongoing patient surveillance, especially in elderly patients who are less able to detect subtle changes in their vision.

  2. Prevention of cystoid macular edema after lens extraction by topical indomethacin; Pt. 3

    International Nuclear Information System (INIS)

    The amounts of prostaglandin (PG) E and Fsub(2α) in the aqueous humor were measured by radioimmuniassay techniques before and immediately after intracapsular and extracapsular cataract extractions. We found that: 1. the levels of PG E and PG Fsub(2α) are elevated by cataract extraction. 2. The elevated levels of PGs can all be prevented by preoperative application of topical indomethacin. 3. No differences in the amounts of PGs biosynthesized during intracapsular and extracapsular lens extraction were found. 4. In some cases, the levels of PG E were still elevated one week after surgery. These findings were used as the basis for our attempts to define the causes of cystoid macular edema (CME) following lens extractions. (orig.)

  3. The effectiveness of early lens extraction with intraocular lens implantation for the treatment of primary angle-closure glaucoma (EAGLE: study protocol for a randomized controlled trial

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    Chew Paul

    2011-05-01

    Full Text Available Abstract Background Glaucoma is the leading cause of irreversible blindness. Although primary open-angle glaucoma is more common, primary angle-closure glaucoma (PACG is more likely to result in irreversible blindness. By 2020, 5·3 million people worldwide will be blind because of PACG. The current standard care for PACG is a stepped approach of a combination of laser iridotomy surgery (to open the drainage angle and medical treatment (to reduce intraocular pressure. If these treatments fail, glaucoma surgery (eg, trabeculectomy is indicated. It has been proposed that, because the lens of the eye plays a major role in the mechanisms leading to PACG, early clear lens extraction will improve glaucoma control by opening the drainage angle. This procedure might reduce the need for drugs and glaucoma surgery, maintain good visual acuity, and improve quality of life compared with standard care. EAGLE aims to evaluate whether early lens extraction improves patient-reported, clinical outcomes, and cost-effectiveness, compared with standard care. Methods/Design EAGLE is a multicentre pragmatic randomized trial. All people presenting to the recruitment centres in the UK and east Asia with newly diagnosed PACG and who are at least 50 years old are eligible. The primary outcomes are EQ-5D, intraocular pressure, and incremental cost per quality adjusted life year (QALY gained. Other outcomes are: vision and glaucoma-specific patient-reported outcomes, visual acuity, visual field, angle closure, number of medications, additional surgery (e.g., trabeculectomy, costs to the health services and patients, and adverse events. A single main analysis will be done at the end of the trial, after three years of follow-up. The analysis will be based on all participants as randomized (intention to treat. 400 participants (200 in each group will be recruited, to have 90% power at 5% significance level to detect a difference in EQ-5D score between the two groups of 0·05

  4. Posterior lens capsule abscess due to Propionibacterium acnes and Staphylococcus epidermidis following extracapsular cataract extraction.

    OpenAIRE

    Manners, R M; Canning, C R

    1991-01-01

    A case of posterior lens capsular abscess occurring many months after an extracapsular cataract extraction is presented. This was caused by a mixed infection involving Propionibacterium acnes and Staphylococcus epidermidis. The significance of Staph epidermidis after such a long postoperative period is uncertain, but the case shows features typical of secondary endophthalmitis due to P acnes, including a long delay in onset and a grumbling course not brought under control by medical treatment...

  5. Cystoid macular oedema after extracapsular cataract extraction and intraocular lens implantation in diabetic patients without retinopathy.

    OpenAIRE

    Menchini, U; Bandello, F; R.Brancato; Camesasca, F I; Galdini, M

    1993-01-01

    Postoperative onset or aggravation of cystoid macular oedema (CMO) in diabetic patients after extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation is a frequent problem. At present little is known about the occurrence and prognosis of this complication in diabetics with no clinically detectable diabetic retinopathy (DR). Twenty five diabetic eyes (24 subjects) without DR and 45 normal eyes (44 subjects) were studied before surgery and 30, 90, 180, 360 days after E...

  6. Effect of intraocular lens implantation on combined extracapsular cataract extraction with trabeculectomy: a comparative study.

    OpenAIRE

    Neumann, R.; Zalish, M.; Oliver, M.

    1988-01-01

    In an attempt to assess the effect of posterior chamber intraocular lens (IOL) implantation on the outcome of combined extracapsular cataract extraction (ECCE) and trabeculectomy we compared 23 eyes subjected to ECCE and trabeculectomy with 23 eyes subjected to a triple procedure-that is, with the addition of IOL implantation. The results showed that IOL implantation did not have a detrimental effect on postoperative IOP reduction, gain in visual acuity, or needs for antiglaucoma medication. ...

  7. Retinal detachment following extracapsular cataract extraction and posterior chamber intraocular lens implantation.

    OpenAIRE

    Ho, P C; Tolentino, F I

    1985-01-01

    Fourteen cases of primary retinal detachment after extracapsular cataract extraction and posterior chamber intraocular lens implantation were treated by scleral buckling surgery. Retinal reattachment was achieved in 100% of the cases. All eyes had a postoperative visual acuity of 6/30 or better; in six eyes the visual acuity was 6/12 or better. We attributed our high anatomical success rate to early detection of the retinal detachment, good visibility of the retinal breaks, lack of inflammato...

  8. Phacolytic glaucoma-its treatment by planned extracapsular cataract extraction with posterior chamber intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Singh Gurdeep

    1994-01-01

    Full Text Available Phacolytic glaucoma has traditionally been treated with intracapsular lens extraction to avoid any anaphylaxis. Various mechanisms have been described for the rise of intraocular pressure in these cases. The present study was undertaken to evaluate the response of extracapsular cataract extraction (ECCE with posterior chamber intraocular lens implantation (PC IOL in five cases of phacolytic glaucoma that occurred between March 1989 and August 1990. A planned extracapsular cataract extraction with can-opener capsulectomy was done in all the cases with placement of a sulcus-fixated modified J-loop Sinskey design intraocular lens. With a mean follow-up period of two years, all patients (100% maintained a normal postoperative intraocular pressure of less than 20 mm Hg without any additional medical therapy. The final best-corrected visual acuity in 4 cases (80% was 6/12 or better, while in one case it was 6/24 due to a senile maculopathy. These results show that ECCE with PC IOL implantation is a safe and efficacious method of visual rehabilitation in cases of phacolytic glaucoma

  9. Ethanol extract of Moringa oliefera prevents in vitro glucose induced cataract on isolated goat eye lens

    Directory of Open Access Journals (Sweden)

    Raghvendra Kurmi

    2014-01-01

    Full Text Available Aim of Study: The aim of current work was to evaluate in vitro anticataract potential of Moringa oliefera extract. Materials and Methods: Goat eye lenses were divided into 4 groups; Group served as control, Group II as toxic control, Group III and Group IV were incubated in extract (250 μg/ml and 500 μg/ml of extract of M. oliefera Group II, III and IV were incubated in 55 mM glucose in artificial aqueous humor to induce lens opacification. Estimation of total, water soluble protein, catalase, glutathione and malondialdehyde along with photographic evaluation of lens was done. Results: Group II (toxic control lenses showed high amount of MDA (Malondialdehyde, soluble, insoluble protein, decreased catalase and glutathione levels, while lenses treated with Moringa oliefera extract (Group III and Group IV showed significant (FNx01 P < 0.05 reduction in MDA and increased level of catalase, glutathione, total and soluble protein. Conclusion: Results of present findings suggest protective effect of Moringa oliefera in prevention of in vitro glucose induced cataract.

  10. Evaluation of high volume extracapsular cataract extraction with posterior chamber lens implantation in Sierra Leone, west Africa.

    OpenAIRE

    Cook, N J

    1996-01-01

    AIMS: Intraocular lens (IOP) implantation in sub-Saharan Africa is not the routine procedure of choice in the treatment of cataract. Previous series consist of small numbers of selected patients. The purpose of this study was to evaluate routine posterior chamber lens implantation in large numbers of consecutive patients. METHODS: 1059 cataract extractions with planned IOL (744 patients) were performed over a 1 year period from August 1993 to July 1994. RESULTS: 94.6% (1002) of eyes showed an...

  11. Ciliary block (malignant) glaucoma after cataract extraction with lens implant treated with YAG laser capsulotomy and anterior hyaloidotomy.

    OpenAIRE

    Halkias, A; Magauran, D M; Joyce, M.

    1992-01-01

    An 84-year-old woman developed high intraocular pressure with a shallow anterior chamber 2 months after an extracapsular cataract extraction with posterior chamber lens implant. The condition did not respond to peripheral iridectomy and removal of the implant but was treated successfully with YAG laser capsulotomy and anterior hyaloidotomy.

  12. Effects of L-Carnitine and Cinnamon Extract Treatment on Lens Crystallins of Rats Fed High Fructose Diet

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    Mohamed H. Mahfouz

    2011-01-01

    Full Text Available Problem statement: Rats fed high dietary fructose are documented to form an acquired model of insulin resistance; the present study aims to investigate possible changes in lens crystallins of rats fed high fructose diet and the effects of administration of each exogenous L-Carnitine (CA and Cinnamon Extract (CE on protein glycation, oxidative stress and redox homeostasis in this rat model. Approach: A total number of 60 male Wister rats of body weight 120-160 g were divided into 4 groups of 15 rats each. Group 1 received control diet, while groups 2, 3 and 4: rats received high fructose diet (60g/100 g diet. After 2 weeks from fructose feeding, animals of group 3 were treated with L-carnitine (300 mg g-1 body weight/day i.p., while animals of group 4 were treated with cinnamon extract (0.5 mL/rat/day orally. At the end of experimental period (30 days, serum levels of glucose and insulin were determined. Lenses of each animal were dissected; molecular weights of crystalline, oxidative stress markers, early glycation of lens proteins and carbonyl group were assayed. Results: A significant decline in antioxidants and increase in lipid peroxidation products, protein oxidation and protein glycation were observed in lens samples obtained from fructose-fed rats. Administration of each CA and CE to fructose-fed rats significantly attenuated oxidative damage and protein glycation and returned levels of antioxidants to near those in control group. Chromatographic analysis of lens crystalline of rats fed high fructose diet showed diffused peaks, indicating crystalline aggregation. Conclusion: The results of the present study indicate that dietary fructose disturbs lens integrity and administration of L-carnitine or cinnamon extract may safeguard the lens by minimizing the protein aggregation, preventing glycation and oxidative stress in animals fed high fructose diet. L-carnitine has more potent effects than CE in this animal model.

  13. SURGICAL OUTCOME OF TRIPLE PROCEDURE AS PENETRATING KERATOPLASTY WITH EXTRACAPSULAR CATARACT EXTRACTION WITH POSTERIOR CHAMBER INTRAOCULAR LENS IMPLANTATION IN PATIENTS WITH BOTH CENTRAL CORNEAL OPACITY AND ADVANCED CATARACT AT RURAL SET UP

    OpenAIRE

    Shubhangi Nigwekar, Kishor Badhe, Neeta Misra, Surekha Bangal

    2015-01-01

    Purpose: To study the surgical outcome of triple procedure as penetrating keratoplasty (PKP) with conventional extra capsular cataract extraction (ECCE) with posterior chamber intraocular lens (PCIOL) implantation in patients with both central corneal opacity and advanced cataract at rural set up. Introduction: When corneal opacity and cataract present together then well-established and effective triple procedure is indicated. Prognosis for a clear graft is good in triple, as graft endothe...

  14. Study on the aqueous humor contents of IL-1β and IL-6 in rabbits after extracapsular extraction of lens

    International Nuclear Information System (INIS)

    Objective: To explore the relationship between the development of posterior capsular opacification and the aqueous humor contents of IL-1β and IL-6 after extracapsular extraction of lens in rabbits. Methods: Extracapsular extraction of lens was performed in 30 New Zealand rabbits. Aqueous humor contents of IL-1β and IL-6 were repeatedly determined with RIA and ophthal-moscopic as well as slit-lamp examination were repeatedly performed to detect any posterior capsular opacification developed on dl, d3, 1w, 2w, 1 month, 3 month posteperatively. Results: The aqueous humor contents of IL-1β and IL-6 increased gradually after operation, reached the peak on d7-d14, then gradually returned to within normal range by 2nd or 3rd month. Beginning from one month post-operatively, posterior capsular opacification was observed in some rabbits. By the end of 3rd month, Grade I opacification was developed in 5 rabbits, Grade H in 9 rabbits with Grade III (fundus view obliterated) in 14 rabbits. Peak IL-1β and IL- 6 content values were positively correlated with grading of future opacification. Conclusion: IL-1β and IL-6 might play important roles in the development of posterior capsular opacification after lens extraction in rabbits. (authors)

  15. Both improvements of the light extraction efficiency and scattered angle of GaN-LED using sub-micron Fresnel lens array

    Science.gov (United States)

    Gu, Xinyu; Chen, Linsen; Shen, Su; Wan, Wenqiang

    2015-11-01

    With the demanding requirements for light source, light emitting diodes (LED) attracts more and more attention because of its inherent advantages such as low power consumption, high reliability and longevity. However, there are two disadvantages for LED, one is the low light extraction efficiency resulting from the total internal reflection, and the other is the relative large scattered angle. In order to improve the light extraction efficiency and collimate the out-coupling light, a sub-micron Fresnel lens array is introduced and investigated in this paper. The focal length of the proposed Fresnel lens is 3μm and the minimum width of the outmost ring is about 150nm. To calculate and analyze the light extraction efficiency and the scattered angle of LED with such Fresnel lens array structure, we optimize the parameters of the Fresnel lens, such as the depth of the Fresnel lens array structure and the thickness of the p-type gallium nitride layer by using the finite difference time domain method (FDTD). By comparing the discussed patterned GaN-based LED with that traditional flat LEDs, it can be found that significant enhancement factor of the light extraction efficiency, which is improved by 3.5 times, can be obtained and the scattered angle at half maximum can be decreased 50° from 60° with this novel Fresnel lens structure. It will be expected that the proposed sub-micron structure can find wide applications in LEDs industry.

  16. Extracting Leaf Area Index by Sunlit Foliage Component from Downward-Looking Digital Photography under Clear-Sky Conditions

    Directory of Open Access Journals (Sweden)

    Yelu Zeng

    2015-10-01

    Full Text Available The development of near-surface remote sensing requires the accurate extraction of leaf area index (LAI from networked digital cameras under all illumination conditions. The widely used directional gap fraction model is more suitable for overcast conditions due to the difficulty to discriminate the shaded foliage from the shadowed parts of images acquired on sunny days. In this study, a new LAI extraction method by the sunlit foliage component from downward-looking digital photography under clear-sky conditions is proposed. In this method, the sunlit foliage component was extracted by an automated image classification algorithm named LAB2, the clumping index was estimated by a path length distribution-based method, the LAD and G function were quantified by leveled digital images and, eventually, the LAI was obtained by introducing a geometric-optical (GO model which can quantify the sunlit foliage proportion. The proposed method was evaluated at the YJP site, Canada, by the 3D realistic structural scene constructed based on the field measurements. Results suggest that the LAB2 algorithm makes it possible for the automated image processing and the accurate sunlit foliage extraction with the minimum overall accuracy of 91.4%. The widely-used finite-length method tends to underestimate the clumping index, while the path length distribution-based method can reduce the relative error (RE from 7.8% to 6.6%. Using the directional gap fraction model under sunny conditions can lead to an underestimation of LAI by (1.61; 55.9%, which was significantly outside the accuracy requirement (0.5; 20% by the Global Climate Observation System (GCOS. The proposed LAI extraction method has an RMSE of 0.35 and an RE of 11.4% under sunny conditions, which can meet the accuracy requirement of the GCOS. This method relaxes the required diffuse illumination conditions for the digital photography, and can be applied to extract LAI from downward-looking webcam images

  17. Role of intraocular lens parameters in visual rehabilitation of patients after extracapsular cataract extraction

    Science.gov (United States)

    Bakutkin, Valery V.; Galanzha, Vladimir A.

    2001-01-01

    The main method of cataract treatment is micro surgical removing of the opaque lens from the eye with implantation of an intra ocular lens. We performed the comparative study of using various IOL models differing in its materials, index of refraction, spectral properties, configuration, shape, size and other features. Before and after the IOL implantation we performed the following test: visual acuity measuring, refractometry, keratometry, laser interferometric retinometry, color perception assessment, digital photo- and videorecording of the eye with image processing and some others. We found a number of correlations between the IOL properties and some characteristics of the patient's vision. The decentration of the IOL optical part more than 1,5 mm conduced to the non-corneal astigmatism and the prismatic effect. A small diameter of the IOL optical part and high index of refraction promotes to the appearance of the optical aberrations. Leucosapphire IOLs revealed the high degree of light reflection and the minimal adhesive ability of the IOL surface. Leucosapphire IOL revealed the high degree of light reflection and the minimal adhesive ability of the IOL surface. PMMA IOL revealed the low reflective power and the high adhesive ability. The best color vision was revealed in patients with PMMA IOL with an additional compound absorbing not only UV light but also short-wave blue light.

  18. Antioxidant activity and phenolic compositions of lentil (Lens culinaris var. Morton) extract and its fractions

    OpenAIRE

    Zou, Yanping; Chang, Sam K.C.; Gu, Yan; Qian, Steven Y.

    2011-01-01

    Phenolic compounds were extracted from Morton lentils using acidified aqueous acetone. The crude Morton extract (CME) was applied onto a macroresin column and desorbed by aqueous methanol to obtain a semi-purified Morton extract (SPME). The SPME was further fractionated over Sephadex LH-20 column into five main fractions (Fr I – Fr V). The phytochemical contents such as total phenolic content (TPC), total flavonoid content (TFC), and condensed tannin content (CTC) of the CME, SPME, and its fr...

  19. Micro/nano-hybrid lens for enhancing light extraction using micro-milling and anodic aluminium oxide (AAO)

    International Nuclear Information System (INIS)

    In the recent past there has been much research towards increasing the transmission of light in optical systems by reducing the Fresnel reflection of radiation, as the reflection of light from surfaces seriously decreases the performance of an optical device. These drawbacks have been overcome by mainly two methods, which are anti-reflective coating and anti-reflective nanostructure formation. In this study, we developed a simple fabrication process for Al micro/nano hybrid lens (MNHL) moulds for efficient light extraction using micro-milling and anodic aluminum oxide (AAO). From these moulds, two different types of polymer MNHL were fabricated using hot-embossing; one was a polymer MNHL that was covered with nanostructures over the entire surface, and the other was one for which only the microlens surface was covered with nanostructures. Two different types of polymer MNHLs were evaluated and compared with each other concerning the light extraction performance. The MNHL with nanostructures only on the microlens surface exhibited a higher light extraction performance than the other by 20.7%. It is expected that the fabricated MNHL can be used for the amplification of small signals when observing the presence of bio-molecules dyed with a fluorescent material. (paper)

  20. Micro/nano-hybrid lens for enhancing light extraction using micro-milling and anodic aluminium oxide (AAO)

    Science.gov (United States)

    Kim, Shin Hyeong; Kim, Min Gu; Kang, Jeong Jin; Lee, Pyeong An; Kim, Bo Hyun; Cho, Young Hak

    2016-01-01

    In the recent past there has been much research towards increasing the transmission of light in optical systems by reducing the Fresnel reflection of radiation, as the reflection of light from surfaces seriously decreases the performance of an optical device. These drawbacks have been overcome by mainly two methods, which are anti-reflective coating and anti-reflective nanostructure formation. In this study, we developed a simple fabrication process for Al micro/nano hybrid lens (MNHL) moulds for efficient light extraction using micro-milling and anodic aluminum oxide (AAO). From these moulds, two different types of polymer MNHL were fabricated using hot-embossing; one was a polymer MNHL that was covered with nanostructures over the entire surface, and the other was one for which only the microlens surface was covered with nanostructures. Two different types of polymer MNHLs were evaluated and compared with each other concerning the light extraction performance. The MNHL with nanostructures only on the microlens surface exhibited a higher light extraction performance than the other by 20.7%. It is expected that the fabricated MNHL can be used for the amplification of small signals when observing the presence of bio-molecules dyed with a fluorescent material.

  1. Audit of exracapsular cataract extraction with posterior chamber intraocular lens implantation in a tertiary eye care center in Ethiopia.

    Science.gov (United States)

    Tilahun, Yonas; Sisay, Alemayehu

    2006-01-01

    A retrospective audit of records of 370 eyes of 315 patients for whom extracapsular cataract extraction with posterior chamber intraocular lens implantation (ECCE-PC IOL) was performed between 1998 and 1999 was made to determine postoperative visual outcome and complications. One hundred and ninety three patients were males and one hundred and seventy seven were females making a male to female ratio of 1:0.9. At two months postoperatively 82 (30.4%) of eyes had uncorrected visual acuity of 6/18 or better; while 176 (53.7%) of eyes attained an uncorrected visual acuity between 6/18 and 6/60, and 31 (11.5%) had visual acuity between 3/60 and 6/60. 340 of 358 (94.9%) had a preoperative visual acuity of < 3/60. As a result of the surgery, the percentage of blind eyes dropped from 94.9% to 4.4%. The commonest intra operative and early postoperative complications encountered were posterior capsular tear with vitreous loss (5.7%) and striate keratopathy (11.1%) respectively. Posterior capsular opacity was documented in 17 (4.6%) eyes as a late postoperative complication. Routine biometry, to calculate Intra ocular Lens (IOL) power was not done and this was the major limitation of the study. In conclusion, the study increases awareness of cataract surgery outcomes and provides a feedback to achieve better results both in terms of quality and quantity in cataract surgery. Further study with biometric measurement is recommended. PMID:17447364

  2. Cost-effectiveness analysis of cataract surgery with intraocular lens implantation: extracapsular cataract extraction versus phacoemulsification

    OpenAIRE

    Mohd R.A. Manaf; Aljunid, Syed M; Faridah H. Annuar; Chuah K. Leong; Normalina Mansor

    2007-01-01

    A randomized single blinded clinical trial to compare the cost-effectiveness of cataract surgery between extracapsular cataract extraction (ECCE) and phacoemulsification (PEA) was conducted at Hospital Universiti Kebangsaan Malaysia (HUKM) from March 2000 until August 2001. The cost of a cataract surgery incurred by hospital, patients and households were calculated preoperatively, one week, two months (for both techniques) and six months (for ECCE only). Effectiveness of cataract surgery was ...

  3. Cost-effectiveness analysis of cataract surgery with intraocular lens implantation: extracapsular cataract extraction versus phacoemulsification

    Directory of Open Access Journals (Sweden)

    Mohd R.A. Manaf

    2007-03-01

    Full Text Available A randomized single blinded clinical trial to compare the cost-effectiveness of cataract surgery between extracapsular cataract extraction (ECCE and phacoemulsification (PEA was conducted at Hospital Universiti Kebangsaan Malaysia (HUKM from March 2000 until August 2001. The cost of a cataract surgery incurred by hospital, patients and households were calculated preoperatively, one week, two months (for both techniques and six months (for ECCE only. Effectiveness of cataract surgery was assessed using Visual Function 14 (VF-14, quality of life measurement specifically for vision. The cost analysis results from each 50 subjects of ECCE and PEA group showed that average cost for one ECCE after six months post-operation is USD 458 (± USD 72 and for PEA is USD 528 (± USD 125. VF-14 score showed a significant increased after a week, two months and six months post-operation compared to the score before operation for both techniques (p<0.001. However, there was no significant difference between them (p = 0.225. This study indicated that ECCE is more cost effective compared to PEA with cost per one unit increment of VF-14 score of USD 14 compared to USD 20 for PEA. (Med J Indones 2007; 16:25-31 Keywords: cataract, cost-effectiveness, extracapsular cataract extraction, phacoemulsification, visual function 14

  4. Clinical observation of small-incision extracapsular cataract extraction with intraocular lens implantation for the treatment of cataract in the sight restoration project

    Directory of Open Access Journals (Sweden)

    Xiao-Jian Cheng

    2014-04-01

    Full Text Available AIM: To analyze the clinical effects of small-incision extracapsular cataract extraction with intraocular lens implantation for the treatment of cataract.METHODS:Totally 642 cases 676 eyes of cataract were treated by small-incision extracapsular cataract extraction with intraocular lens implantation. Complication during and after operations and postoperative visual acuity was observed.RESULTS:Visual acuity of 670 eyes was ≥0.05 and off-blindness rate was 99.11%, and there was 627 eyes ≥0.3 and the off-disability rate was 92.75% after 1mo. Rupture of posterior capsule during surgery occurred in 24 eyes. Fifty-four eyes were corneal edema, and anterior chamber exudation were 26 eyes, and 23 eyes were hypertension after operation. CONCLUSION: There are a little complications during and after operation for cataract treated by small-incision extracapsular cataract extraction with intraocular lens implantation. Patients have good recovery after operation. This operation does not need high-standard equipments and is suitable in the sight restoration project.

  5. Audit of extracapsular cataract extraction and posterior chamber lens implantation as a routine treatment for age related cataract in east Africa

    OpenAIRE

    Yorston, D; Foster, A.

    1999-01-01

    AIMS—To evaluate the outcome of extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens implantation (PC-IOL) in an African eye clinic during the transition from intracapsular cataract extraction to ECCE and PC-IOL.
METHODS—A retrospective survey of 461 consecutive operations for age related cataract with a mean follow up of 52.9 weeks (range 0-275) and a minimum follow up of 4 weeks in 87.9% of eyes.
RESULTS—A best corrected vision of 6/18 or better was obtained in 94...

  6. 'In-the-bag' hyphaema--a rare complication of posterior chamber lens implantation.

    OpenAIRE

    Thomas, R; Aylward, G W; Billson, F A

    1989-01-01

    A 72-year-old woman developed a hyphaema on the first postoperative day after a combined trabeculectomy and extracapsular cataract extraction with posterior chamber intraocular lens implantation. On the second day the blood had redistributed to accumulate 'in the bag' posterior to the intraocular lens and had formed a fluid level. Postural drainage helped to clear the hyphaema from both locations, with no short-term effect on visual function or the filtering bleb.

  7. Extracting structural and functional features of widely distributed biological circuits with single cell resolution via tissue clearing and delivery vectors.

    Science.gov (United States)

    Treweek, Jennifer Brooke; Gradinaru, Viviana

    2016-08-01

    The scientific community has learned a great deal from imaging small and naturally transparent organisms such as nematodes and zebrafish. The consequences of genetic mutations on their organ development and survival can be visualized easily and with high-throughput at the organism-wide scale. In contrast, three-dimensional information is less accessible in mammalian subjects because the heterogeneity of light-scattering tissue elements renders their organs opaque. Likewise, genetically labeling desired circuits across mammalian bodies is prohibitively slow and costly via the transgenic route. Emerging breakthroughs in viral vector engineering, genome editing tools, and tissue clearing can render larger opaque organisms genetically tractable and transparent for whole-organ cell phenotyping, tract tracing and imaging at depth. PMID:27393829

  8. Application of thermal lens response to monitor health status of red blood cells: A quantitative study of the cell death process by extracting thermal diffusivity and size

    Science.gov (United States)

    Vasudevan, Srivathsan; Chen, George Chung Kit; Andika, Marta

    2010-03-01

    We explore monitoring the death process of individual red blood cells (RBC) quantitatively by using thermal lens (TL) response. TL response is a noninvasive excitation/probe technique that reflects photothermal parameters (e.g., absorption, thermal diffusivity, size, etc.). Since these parameters of cells change significantly during certain biological processes, real-time TL response was performed to monitor RBC death process when incubated with ionomycin. Theoretical model developed was applied to curve-fit the TL response for extracting thermal diffusivity and size of cells. Thermal diffusivity of dying RBC is found increased by 1.7 times in comparison with healthy cell.

  9. Broken intraocular lens during cataract surgery.

    OpenAIRE

    Kirkpatrick, J N; Cook, S D

    1992-01-01

    A case of planned routine extracapsular cataract extraction is described where surgery was complicated peroperatively by fracture of the posterior chamber lens implant. The technique of lens implantation is discussed.

  10. Fresnel Lens

    Science.gov (United States)

    Watson, Michael D.; Scott, Steve; Lamb, David; Zimmerman, Joe E. (Technical Monitor)

    2001-01-01

    Fresnel lenses span the full range of sizes from lens a few micrometers in diameter to lens several meters in diameter. These lenses are utilized in various fields including optical communication, theatrical lighting, office equipment, video entertainment systems, solar concentrators, and scientific research instruments. These lenses function either as diffractive or refractive optical elements depending on the geometrical feature size of the lens. The basic functions of these lenses is described followed by an overview of fabrication methods. A summary of applications is then provided illustrating the rich variety of applications for which fresnel lenses may be designed to fulfill.

  11. SURGICAL OUTCOME OF TRIPLE PROCEDURE AS PENETRATING KERATOPLASTY WITH EXTRACAPSULAR CATARACT EXTRACTION WITH POSTERIOR CHAMBER INTRAOCULAR LENS IMPLANTATION IN PATIENTS WITH BOTH CENTRAL CORNEAL OPACITY AND ADVANCED CATARACT AT RURAL SET UP

    Directory of Open Access Journals (Sweden)

    Shubhangi Nigwekar, Kishor Badhe, Neeta Misra, Surekha Bangal

    2015-10-01

    Full Text Available Purpose: To study the surgical outcome of triple procedure as penetrating keratoplasty (PKP with conventional extra capsular cataract extraction (ECCE with posterior chamber intraocular lens (PCIOL implantation in patients with both central corneal opacity and advanced cataract at rural set up. Introduction: When corneal opacity and cataract present together then well-established and effective triple procedure is indicated. Prognosis for a clear graft is good in triple, as graft endothelium does not touch the hard nucleus which may occur in two steps or sequential surgery. It provides faster visual rehabilitation. Being single step procedure it reduces patient’s hospital stay, postoperative care and follows up visits. Methodology: In this hospital based observational , three years longitudinal study, we studied the surgical outcome of relatively rare one step triple procedure as PKP with conventional ECCE with PCIOL implantation in sulcus or in bag, in patients with both central corneal opacity and advanced cataract at rural set up. The outcome measures included graft clarity on slit lamp, postoperative unaided visual acuity with Snellen’s chart and the occurrence of postoperative complications after taking IEC permission and informed written consent in local language from study patients. Results: Out of 13 study patients mean age was 61.15yrs (Range50-80yrs. Follow up range was 9-34 months. At final follow up 9 patients (69.23% had clear grafts and 61.52% patients gained visual acuity >6/24. Graft failure was the most common post operative complication in 30.76% followed by Posterior capsular opacification (PCO in 15.38% patients which was treated well with YAG laser capsulotomy. Conclusion: Triple procedure gives good results in respect to graft clarity, unaided vision, and faster rehabilitation.

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

    Directory of Open Access Journals (Sweden)

    Solange Teresinha Carpes

    2007-12-01

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

  13. 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 of probabil......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 of...... probabilistic functionalism, and concerns the environment and the mind, and adaptation by the latter to the former. This entry is about the lens model, and probabilistic functionalism more broadly. Focus will mostly be on firms and their employees, but, to fully appreciate the scope, we have to keep in mind the...

  14. Double-mirror peripheral vitrectomy lens.

    Science.gov (United States)

    Ohji, M; Tano, Y

    1995-11-01

    Many surgeons use prism lenses to see the periphery of the fundus during vitrectomy; however, chromatic aberrations in higher-power prismatic lenses cause blurring of the peripheral image. For better visualization of the periphery of the fundus, we developed a new contact lens, the double-mirror peripheral vitrectomy lens. The new lens is a quartz cylinder with two mirrors, and it provides a crisp, clear, upright image of much more of the peripheral fundus than is visible through conventional prism lenses. The new lens also provides a wider area of view than conventional prism lenses. PMID:7487611

  15. Keratoplasty and cataract extraction

    OpenAIRE

    Panda Anita; Kumar T

    1991-01-01

    Fifty eyes were evaluated following penetrating keratoplasty and cataract extraction. Twenty five of them had intracapsular lens extraction while the remaining 25 had intercapsular method of extracapsular lens extraction. Both operative and post operative complications were more in group I. Visual outcome and graft clarity were also better in eyes of group II. Combined keratoplasty and intercapsular method of extracapsular lens extraction was recommended in eyes having both corneal and lentic...

  16. Keratoplasty and cataract extraction

    Directory of Open Access Journals (Sweden)

    Panda Anita

    1991-01-01

    Full Text Available Fifty eyes were evaluated following penetrating keratoplasty and cataract extraction. Twenty five of them had intracapsular lens extraction while the remaining 25 had intercapsular method of extracapsular lens extraction. Both operative and post operative complications were more in group I. Visual outcome and graft clarity were also better in eyes of group II. Combined keratoplasty and intercapsular method of extracapsular lens extraction was recommended in eyes having both corneal and lenticular pathology.

  17. Aging Changes of Lens Physical Properties

    Directory of Open Access Journals (Sweden)

    Kudryavtseva Y.V.

    2011-06-01

    Full Text Available The aim of the work is to assess aging changes of lens physical properties. Materials and Methods. There have been examined the patients aged 57—90 years. 73 lens nuclei with cataract of different maturity degree taken by means of extracapsular cataract extraction have been studied. Before the operation there has been determined relative echodensity of lens according to an original technique and assessed the lens colour and nuclear mass. Results. Brown colour of the lens nucleus is slightly increasing with years (r=0.4; р<0.05. Mean value of relative lens echodensity is 0.59±0.01. An average mass of lens nucleus is 98.3±1.0 mg, and its average density is 1312.0±12.0 mg/m2. Mature cataract is revealed to be not always hard (r=0.4; р<0.05, i.e. in this case the relation is inverse. When lens density increases, mechanical hardness of its nucleus grows up (r=0.4, р<0.05. At the same time mechanical density of lens nucleus increases with the increase of years (r=0.74, р<0.05. Age is stated not to be a controlling factor in cataract occurring and progressing. Conclusion. Lens mechanical characteristics depend on its chemical composition, and in aging brown colour of the lens increases, mechanical density of lens nucleus grows up, and vision can change slightly. Cataract maturation and the increase of lens density are chemically different processes and independent of each other.

  18. Lens system for SIMS analysis

    International Nuclear Information System (INIS)

    A powerful version of the charge-density method is applied to the study of a combined objective and emission lens, suitable for highly localized analysis of a flat sample surface. This lens can extract secondary ions of equal or opposite polarity to that of the primary particles. A computer simulation of the ion trajectories for both modes is made. The behaviour for different values of the geometric parameters and polarizations is analyzed and useful data for design such as primary beam demagnification and secondary image position are given. (author) 4 refs

  19. Clear Evidence of Carcinogenic Activity by a Whole-Leaf Extract of Aloe barbadensis Miller (Aloe vera) in F344/N Rats

    OpenAIRE

    Boudreau, Mary D.; Mellick, Paul W.; Olson, Greg R.; Felton, Robert P.; Thorn, Brett T.; Beland, Frederick A.

    2012-01-01

    Aloe barbadensis Miller (Aloe vera) is an herbal remedy promoted to treat a variety of illnesses; however, only limited data are available on the safety of this dietary supplement. Drinking water exposure of F344/N rats and B6C3F1 mice to an Aloe vera whole-leaf extract (1, 2, and 3%) for 13 weeks resulted in goblet cell hyperplasia of the large intestine in both species. Based upon this observation, 2-year drinking water studies were conducted to assess the carcinogenic potential of an Aloe ...

  20. Contact lens in keratoconus

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2013-01-01

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

  1. Periocular migration of an intraocular lens.

    OpenAIRE

    Jenkins, C.

    1992-01-01

    A woman presented with a painful eye 6 weeks after cataract extraction and intraocular lens implantation. In the past she had had a sector iridectomy for iris bombé caused by chronic anterior uveitis. On examination the three central corneal sutures were absent, whilst the medial and lateral sutures had broken and were protruding from the section. The eye was quiet and the section intact. Combined clinical and ultrasound examination failed to locate the intraocular lens. Four months postopera...

  2. Observations on the relationship between the levels of serum IL-6 and TNF-α and the severity of diabetic retinopathy and curative effect in cataract extraction with intraocular lens implantation in diabetics

    International Nuclear Information System (INIS)

    Objective: To determine the sequential changes of blood levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in diabetics with extracapsular extraction and posterior chamber intraocular lens implantation and to study their correlation with curative effects and pos-operative complications. Methods: The serum concentrations of IL-6 and TNF-α in 39 diabetics and non-diabetics were measured by radioimmunoassay at preoperative, post-operative and on days 7, 14 and 90 postoperatively. Results: There was significant difference in the levels of the two factors between the diabetic group and non-diabetic group preoperatively (P<0.05). The serum levels of the two factors in patients with proliferative diabetic retinopathy were higher than those in non-diabetic retinopathy, and simple diabetic retinopathy post-operative (P<0.01). Post-operative complication rate was higher in patients with proliferative diabetic retinopathy than those without retinopathy and those having simple diabetic retinopathy. Conclusion: The levels of the two factors correlate with complications and curative effect of patients with proliferative diabetic retinopathy undergoing intraocular lens implantation

  3. Contact Lens Solution Toxicity

    Science.gov (United States)

    ... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...

  4. Impregnação inadvertida da cápsula posterior do cristalino com azul de tripano durante a facectomia extracapsular: relato de caso Unintentional staining of lens posterior capsule with trypan blue during extracapsular cataract extraction: case report

    Directory of Open Access Journals (Sweden)

    Frederico França Marques

    2006-02-01

    Full Text Available Relato de complicação relacionada ao uso do azul de tripano 0,1% ocorrida ao corar a cápsula anterior do cristalino em facectomia extracapsular com implante de lente intra-ocular. O corante foi injetado sob alta pressão utilizando a técnica de bolha de ar ocasionando a migração deste através da zônula e conseqüente perda do reflexo vermelho no peroperatório dificultando os passos subseqüentes à extração da catarata e comprometendo temporariamente a acuidade visual no pós-operatório. Tendo como objetivo evitar esta complicação, os autores descrevem ainda, o uso da "Técnica de bolha de ar modificada" no qual o viscoelástico dispersivo é injetado no espaço iridolenticular 360° para compor uma barreira de proteção.Report of a complication related to the use of 0.1% trypan blue during capsular staining of the anterior crystalline lens capsule in an extracapsular cataract extraction with intraocular lens implantation. The capsular dye was injected using an air-bubble technique, inadvertently, it was done using high pressure dispersing the dye through the zonules leading to a complete losts of red reflex, the following steps of the procedure becoming more difficult after the cataract extraction and causing a temporary disturbance of visual acuity in the postoperative period. In order to avoid this complication, the authors also describe the use of "Modified air-bubble technique" where dispersive viscoelastic is placed into the iridolenticular space 360° to create a protection barrier.

  5. Iron oxide functionalized graphene oxide as an efficient sorbent for dispersive micro-solid phase extraction of sulfadiazine followed by spectrophotometric and mode-mismatched thermal lens spectrometric determination.

    Science.gov (United States)

    Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Abbasi, Amir; Rashidian Vaziri, Mohammad Reza; Behjat, Abbas

    2016-01-15

    A simple and rapid dispersive micro-solid phase extraction (DMSPE) combined with mode-mismatched thermal lens spectrometry as well as fiber optic linear array spectrophotometry was developed for the separation, extraction and determination of sulfadiazine. Graphene oxide was synthesized using the modified Hummers method and functionalized with iron oxide nanoparticles by means of a simple one step chemical coprecipitation method. The synthesized iron oxide functionalized graphene oxide was utilized as an efficient sorbent in DMSPE of sulfadiazine. The retained analyte was eluted by using 180µL of a 6:4 mixture of methanol/acetic acid solution and was spectrophotometrically determined based on the formation of an azo dye through coupling with thenoyltrifluoroacetone. Under the optimized conditions, with the application of spectrophotometry technique and with a sample volume of 100mL, the method exhibited a linear dynamic range of 3-80µg L(-1) with a detection limit of 0.82µg L(-1), an enrichment factor of 200 as well as the relative standard deviations of 2.6% and 4.3% (n=6) at 150µg L(-1) level of sulfadiazine for intra- and inter-day analyses, respectively. Whereas, through the application of the thermal lens spectrometry and a sample volume of 10mL, the method exhibited a linear dynamic range of 1-800µg L(-1) with a detection limit of 0.34µg L(-1) and the relative standard deviations of 3.1% and 5.4% (n=6) at 150µg L(-1) level of sulfadiazine for intra- and inter-day analyses, respectively. The method was successfully applied to the determination of sulfadiazine in milk, honey and water samples. PMID:26592647

  6. LensClean revisited

    CERN Document Server

    Wucknitz, O

    2004-01-01

    We discuss the LensClean algorithm which for a given gravitational lens model fits a source brightness distribution to interferometric radio data in a similar way as standard Clean does in the unlensed case. The lens model parameters can then be varied in order to minimize the residuals and determine the best model for the lens mass distribution. Our variant of this method is improved in order to be useful and stable even for high dynamic range systems with nearly degenerated lens model parameters. Our test case B0218+357 is dominated by two bright images but the information needed to constrain the unknown parameters is provided only by the relatively smooth and weak Einstein ring. The new variant of LensClean is able to fit lens models even in this difficult case. In order to allow the use of general mass models with LensClean, we develop the new method LenTil which inverts the lens equation much more reliably than any other method. This high reliability is essential for the use as part of LensClean. Finally...

  7. Clearing, transparency, and collateral

    OpenAIRE

    Francesco Carli; Francesca Carapella; Gaetano Antinolfi

    2014-01-01

    In an environment of Over-The-Counter trading with adverse selection we study traders' incentives to screen their counterparties under different clearing arrangements. When the clearing arrangement is also a choice, traders decide which types of transactions to clear under each arrangement, with signicant consequences for transparency and collateral requirements. The key trade-off is between insurance and the value of information: on one hand risk averse traders want to smooth consumption and...

  8. Len Yi Part 2

    OpenAIRE

    Bsod nams rgyal mtshan

    2011-01-01

    INTRODUCTION: Sonan Jetsun (Bsod nams rgyal mtshan) filmed this material 12-22 January 2008 in Len yi (Lianyi) Village, Sgong po (Gongbo) Township, Sde rong (Derong) County, Dkar mdzes (Ganzi) Tibetan Autonomous Prefecture, Si khron (Sichuan) Province, PR China. The film features the Tibetan New Year, Bkra shis Temple, and ordinary people's lives in Len yi Village. Sonan Jetsun also edited the material and plans to give it to Len yi villagers on DVD/ VCD. LOCATION: Lianyi Village is 200 k...

  9. 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.

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

    Indian Academy of Sciences (India)

    Digvijay Singh Shekhawat; O P Jangir; Acharya Prakash; Suthar Pawan

    2001-12-01

    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 IU/ml in adult) was given to the operated animals. Vitamin A was found to induce lens regeneration in not only young but also in adult mice. Regenerated lenses were similar in shape, size, transparency and histological features to normal intact lenses.

  11. Glycation precedes lens crystallin aggregation

    International Nuclear Information System (INIS)

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both [3H]NaBH4 reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated

  12. Lens auto-centering

    Science.gov (United States)

    Lamontagne, Frédéric; Desnoyers, Nichola; Doucet, Michel; Côté, Patrice; Gauvin, Jonny; Anctil, Geneviève; Tremblay, Mathieu

    2015-09-01

    In a typical optical system, optical elements usually need to be precisely positioned and aligned to perform the correct optical function. This positioning and alignment involves securing the optical element in a holder or mount. Proper centering of an optical element with respect to the holder is a delicate operation that generally requires tight manufacturing tolerances or active alignment, resulting in costly optical assemblies. To optimize optical performance and minimize manufacturing cost, there is a need for a lens mounting method that could relax manufacturing tolerance, reduce assembly time and provide high centering accuracy. This paper presents a patent pending lens mounting method developed at INO that can be compared to the drop-in technique for its simplicity while providing the level of accuracy close to that achievable with techniques using a centering machine (usually innovative auto-centering method is based on the use of geometrical relationship between the lens diameter, the lens radius of curvature and the thread angle of the retaining ring. The autocentering principle and centering test results performed on real optical assemblies are presented. In addition to the low assembly time, high centering accuracy, and environmental robustness, the INO auto-centering method has the advantage of relaxing lens and barrel bore diameter tolerances as well as lens wedge tolerances. The use of this novel lens mounting method significantly reduces manufacturing and assembly costs for high performance optical systems. Large volume productions would especially benefit from this advancement in precision lens mounting, potentially providing a drastic cost reduction.

  13. EXTRACT

    DEFF Research Database (Denmark)

    Pafilis, Evangelos; Buttigieg, Pier Luigi; Ferrell, Barbra;

    2016-01-01

    The microbial and molecular ecology research communities have made substantial progress on developing standards for annotating samples with environment metadata. However, sample manual annotation is a highly labor intensive process and requires familiarity with the terminologies used. We have the...... and text-mining-assisted curation revealed that EXTRACT speeds up annotation by 15-25% and helps curators to detect terms that would otherwise have been missed.Database URL: https://extract.hcmr.gr/......., organism, tissue and disease terms. The evaluators in the BioCreative V Interactive Annotation Task found the system to be intuitive, useful, well documented and sufficiently accurate to be helpful in spotting relevant text passages and extracting organism and environment terms. Comparison of fully manual...

  14. 婴儿先天性白内障摘除一期人工晶状体植入的研究进展%Primary intraocular lens implantation after extraction of congenital cataract in infants

    Institute of Scientific and Technical Information of China (English)

    刘馨; 罗怡

    2012-01-01

    近年来,婴儿先天性白内障摘除后一期植入人工晶状体受到越来越多眼科医生的认可,并在临床实践中逐步开展.25G玻璃体切除系统在婴儿白内障手术中的应用,大大降低了术后并发症的发生;新型屈光度计算公式和近视漂移预测公式的发展,提高了人工晶状体屈光度选择的准确性;更适合婴幼儿的人工晶状体和弱视训练方法的发展,提升了术后视功能重建的效果.%Primary intraocular lens (IOL) implantation after extraction of congenital cataract in infants has been accepted and gradually applied to clinic by an increasing number of ophthalmologists in recent years.Incidence of postoperative complications has largely reduced after application of the 25-gauge vitrectomy system in cataract surgery in infants.Accuracy of IOL power calculation has been increased because of the developments of new generation of I0L power calculation formula and prediction formula of myopia shift.Visual rehabilitation has improved due to the developments of the infants-suitable IOLs and the means of amblyopia training.

  15. Bilateral spontaneous crystalline lens dislocation to the anterior chamber: A case report

    OpenAIRE

    Jovanović Miloš

    2013-01-01

    Introduction. There are various reasons for the lens dislocation. Spontaneous dislocation of a clear lens is extremely rare, especially its dislocation to the anterior chamber. Case Outline. The author presents a case of spontaneous clear lens dislocation to the anterior chamber in both eyes in a patient without the history of any trauma. Dislocation occurred spontaneously, first in the left eye, along with a sudden decrease of vision. The ophthalmologist f...

  16. Snow-clearing operations

    CERN Multimedia

    EN Department

    2010-01-01

    To facilitate snow clearing operations, which commence at 4.30 in the morning, all drivers of CERN cars are kindly requested to park them together in groups. This will help us greatly assist us in our work. Thank-you for your help. Transport Group / EN-HE Tel. 72202

  17. Hudson_Clearing.m

    OpenAIRE

    Rigby, S.E.

    2014-01-01

    This MATLAB code allows the user to generate a series of keyword files for use with LS-DYNA to predict the blast load and evaluate the effects of blast wave clearing on a finite-sized, deformable target. User doccumentation is provided.

  18. Reflections From a Fresnel Lens

    Science.gov (United States)

    Keeports, David

    2005-01-01

    Reflection of light by a convex Fresnel lens gives rise to two distinct images. A highly convex inverted real reflective image forms on the object side of the lens, while an upright virtual reflective image forms on the opposite side of the lens. I describe here a set of laser experiments performed upon a Fresnel lens. These experiments provide…

  19. Cost analysis of cataract surgery with intraocular lens implantation: a single blind randomised clinical trial comparing extracapsular cataract extraction and phacoemulsification.

    Science.gov (United States)

    Rizal, A M; Aljunid, S M; Normalina, M; Hanom, A Faridah; Chuah, K L; Suzainah, Y; Zainal, M; Azman, A B

    2003-08-01

    A randomised single blinded clinical trial to compare the cost of cataract surgery between extracapsular cataract extraction (ECCE) and phacoemulsification (PEA) was conducted at Hospital Universiti Kebangsaan Malaysia (HUKM) between March and December 2000. A total of 60 patients were included in this study. The cost of a cataract surgery incurred by hospital, patients and households up to two months after discharge were included. The costs of training, loss of patients' income after discharge and intangible costs were excluded. Results showed that the average cost for one ECCE operation is RM1,664.46 (RM1,233.04-RM2,377.64) and for PEA is RM1,978.00 (RM1,557.87-RM3,334.50). During this short period of follow up, it can be concluded that ECCE is significantly cheaper than PEA by an average difference of RM 313.54 per patient (p < 0.001). Cost of equipment and low frequency of PEA technique done in HUKM were the two main reasons for the high unit cost of PEA as compared to ECCE. PMID:14750378

  20. Contact Lens Risks

    Science.gov (United States)

    ... Health and Consumer Devices Consumer Products Contact Lenses Contact Lens Risks Share Tweet Linkedin Pin it More ... redness blurred vision swelling pain Serious Hazards of Contact Lenses Symptoms of eye irritation can indicate a ...

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Sep 10, 2015 Contact Lens Horror Stories: Poor Care Can Lead to Blindness Sep 09, 2015 How to Correct High Myopia Feb 27, 2015 More Eye Health News Pet Fish Fitted with Fake Eye in ...

  2. Colored Contact Lens Dangers

    Medline Plus

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

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, ... placed on the eye can lower internal eye pressure by about 20 percent for half a year. ...

  4. Colored Contact Lens Dangers

    Medline Plus

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

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... same level of care or consideration as a standard contact lens because they can be purchased over- ... lifestyle choices can directly affect your eyes. The best way to take care of your eyes during ...

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lenses do not require the same level of care or consideration as a standard contact lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ...

  7. Analysis of Postoperative Corneal Astigmatism after Phacoemulsification Through a Clear Corneal Incision

    OpenAIRE

    Sušić, Nikola; Brajković, Jasenka; Kalauz-Surać, Ivana

    2007-01-01

    The aim of the study was to analyze postoperative corneal astigmatism after phacoemulsification with intraocular lens implantation through a clear corneal incision. This prospective study included 22 eyes (10 right and 12 left eyes) having had phacoemulsification with implantation of a foldable intraocular lens through a clear corneal incision. A superotemporal incision was used in all right eyes, and superonasal incision in all left eyes. Astigmatism was measured by autorefractometer-keratom...

  8. Terahertz Artificial Dielectric Lens

    Science.gov (United States)

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-03-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  9. Changes in Monkey Crystalline Lens Spherical Aberration During Simulated Accommodation in a Lens Stretcher

    Science.gov (United States)

    Maceo Heilman, Bianca; Manns, Fabrice; de Castro, Alberto; Durkee, Heather; Arrieta, Esdras; Marcos, Susana; Parel, Jean-Marie

    2015-01-01

    Purpose. The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses. Methods. Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4–16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values. Results. The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from −6.3 ± 0.7 μm for young lenses to −5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and −2.6 ± 0.5 μm, respectively. Conclusions. Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age. PMID:25670492

  10. Clear cell sarcoma

    Directory of Open Access Journals (Sweden)

    Pinar Ozuguz

    2014-01-01

    Full Text Available Malignant melanoma (MM of soft tissue, also called clear cell sarcoma (CCS of tendons and aponeuroses, derives from the neural crest. CCS is similar morphologically to MM but has no precursor skin lesion, and instead, has a characteristic chromosomal translocation. Prognosis is related to the tumor size. Early recognition and initial radical surgery is the key to a favorable outcome. The tumor has to be differentiated from other benign and malignant lesions of the soft tissues, such as fibrosarcoma. The demonstration of melanin and a positive immunohistochemical reaction for S-100 protein and HMB-45 can assist in the differential diagnosis. We report the case of a 58-year-old woman with CCS arising from the soft tissue of her little finger.

  11. Late opacification of a hydrophilic acrylic intraocular lens

    Directory of Open Access Journals (Sweden)

    Al-Bdour Muawyah

    2008-01-01

    Full Text Available Cataract extraction and intraocular lens implantation is considered to be a safe procedure in most cases. However, the new advances in the surgical technique namely phacoemulsification and hence the increased use of foldable intraocular lenses have given rise to new complications including late opacification of intraocular lenses. In this case we report late opacification of a foldable hydrophilic acrylic intraocular lens and the surgical technique for its exchange.

  12. Luneburg lens in silicon photonics

    OpenAIRE

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-01-01

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms. (C) 2011 Optical Society of America

  13. Frequency selective lens antenna

    OpenAIRE

    Thornton, J.; Haines, P.

    2007-01-01

    A variant of the hemispherical microwave lens antenna is reported where the ground plane region is modified through use of a frequency selective surface. This allows discrimination of frequencies by two closely spaced primary feeds. A scale model is reported operating at 12 and 30 GHz.

  14. Automatic intraocular lens segmentation and detection in optical coherence tomography images.

    Science.gov (United States)

    Gillner, Melanie; Eppig, Timo; Langenbucher, Achim

    2014-05-01

    We present a new algorithm for automatic segmentation and detection of an accommodative intraocular lens implanted in a biomechanical eye model. We extracted lens curvature and position. The algorithm contains denoising and fan correction by a multi-level calibration routine. The segmentation is realized by an adapted canny edge detection algorithm followed by a detection of lens surface with an automatic region of interest search to suppress non-optical surfaces like the lens haptic. The optical distortion of lens back surface is corrected by inverse raytracing. Lens geometry was extracted by a spherical fit. We implemented and demonstrated a powerful algorithm for automatic segmentation, detection and surface analysis of intraocular lenses in vitro. The achieved accuracy is within the expected range determined by previous studies. Future improvements will include the transfer to clinical anterior segment OCT devices. PMID:23928353

  15. Use of Digital Image Technology to 'Clearly' Depict Global Change

    Science.gov (United States)

    Molnia, B. F.; Carbo, C. L.

    2014-12-01

    Earth is dynamic and beautiful. Understanding why, when, how, and how fast its surface changes yields information and serves as a source of inspiration. The artistic use of geoscience information can inform the public about what is happening to their planet in a non-confrontational and apolitical way. While individual images may clearly depict a landscape, photographic comparisons are necessary to clearly capture and display annual, decadal, or century-scale impacts of climate and environmental change on Earth's landscapes. After years of effort to artistically communicate geoscience concepts with unenhanced individual photographs or pairs of images, the authors have partnered to maximize this process by using digital image enhancement technology. This is done, not to manipulate the inherent artistic content or information content of the photographs, but to insure that the comparative photo pairs produced are geometrically correct and unambiguous. For comparative photography, information-rich historical photographs are selected from archives, websites, and other sources. After determining the geographic location from which the historical photograph was made, the original site is identified and eventually revisited. There, the historical photos field of view is again photographed, ideally from the original location. From nearly 250 locations revisited, about 175 pairs have been produced. Every effort is made to reoccupy the original historical site. However, vegetation growth, visibility reduction, and co-seismic level change may make this impossible. Also, inherent differences in lens optics, camera construction, and image format may result in differences in the geometry of the new photograph when compared to the old. Upon selection, historical photos are cleaned, contrast stretched, brightness adjusted, and sharpened to maximize site identification and information extraction. To facilitate matching historical and new images, digital files of each are overlain in

  16. Flat acoustic lens by acoustic grating with curled slits

    International Nuclear Information System (INIS)

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

  17. To Clear or Not To Clear - That Is the Question

    OpenAIRE

    Downing, Adam; Childs, Corey; Porr, C. A. Shea

    2009-01-01

    Many options exist if you do decide to clear land. Regardless of the option you choose, the primary goal should be the same: to minimize soil loss and movement during and immediately after the land clearing process.

  18. Kataract Phacoemulsification in the Treatment of Patients with Combined Lens Pathology

    OpenAIRE

    Smetankin I.G.

    2011-01-01

    There have been discussed present principles and strategic approaches in cataract treatment in patients with combined lens pathology (glaucoma, pseudoexfoliative syndrome, lens subluxation, syndrome of rigid iris) as the most troublesome group of patients whose frequency of intra- and postoperative complications after cataract extraction has remained relatively high. Turn to extracapsular phacoemulsification of lens contributes to reduction of complication rate in this group of patients thoug...

  19. Functional modular contact lens

    Science.gov (United States)

    Shum, Angela J.; Cowan, Melissa; Lähdesmäki, Ilkka; Lingley, Andrew; Otis, Brian; Parviz, Babak A.

    2009-08-01

    Tear fluid offers a potential route for non-invasive sensing of physiological parameters. Utilization of this potential depends on the ability to manufacture sensors that can be placed on the surface of the eye. A contact lens makes a natural platform for such sensors, but contact lens polymers present a challenge for sensor fabrication. This paper describes a microfabrication process for constructing sensors that can be integrated into the structure of a functional contact lens in the future. To demonstrate the capabilities of the process, an amperometric glucose sensor was fabricated on a polymer substrate. The sensor consists of platinum working and counter electrodes, as well as a region of indium-tin oxide (ITO) for glucose oxidase immobilization. An external silver-silver chloride electrode was used as the reference electrode during the characterization experiments. Sensor operation was validated by hydrogen peroxide measurements in the 10- 20 μM range and glucose measurements in the 0.125-20 mM range.

  20. The human anterior lens capsule--an attempted chemical debridement of epithelial cells by ethylenediaminetetracetic acid (EDTA) and trypsin.

    OpenAIRE

    Humphry, R. C.; Davies, E. G.; Jacob, T J; Thompson, G M

    1988-01-01

    The addition of edetic acid (EDTA) or trypsin to the infusion during a simulated extracapsular cataract extraction on cadaver eyes facilitates the removal of lens epithelial cells from the anterior capsule. Modification of the chemical composition of infusions used during extracapsular surgery may maximise lens epithelial cell removal and hence reduce the incidence of opacification of the posterior capsule after cataract extraction.

  1. Silicone oil-intraocular lens interaction: which lens to use?

    OpenAIRE

    McLoone, E; Mahon, G; Archer, D.; Best, R

    2001-01-01

    AIM—To determine a suitable intraocular lens for implantation in patients at high risk of lens exposure to silicone oil in their lifetime.
METHODS—PMMA, AcrySof, AR40, AQUA-Sense, and Raysoft lenses were examined. Each lens was immersed for 5 minute intervals in balanced salt solution (BSS), in stained silicone oil, and again in BSS before being photographed in air and in BSS. Percentage silicone oil coverage of the lens optic was determined.
RESULTS—The mean percentage coating (MPC) for the ...

  2. Clearing and vegetation management issues

    International Nuclear Information System (INIS)

    Clearing and continued management of incompatible plant species is critical to maintaining safe and reliable transmission and distribution lines at British Columbia Hydro. As part of a general review of policies regarding rights-of-way, the clearing of BC Hydro rights-of-way was studied by a task team in order to formulate a set of recommended policies and procedures to guide employees in all rights-of-way decisions, and to provide clear direction for resolution of all rights-of-way issues in a cost-effective manner. Issues reviewed were: clearing standards and line security standardization for transmission circuits; clearing rights for removal of trees or management of vegetation beyond the statutory right-of-way; clearing and vegetation management procedures; tree replacement; arboricultural techniques; periodic reviewing of clearing practices; compensation for tree removal; herbicide use; and heritage and wildlife trees. Justification for the recommendation is provided along with alternate options and costs of compliance

  3. Clinical analysis of delayed onset postoperative uveitis after cataract extraction with intraocular lens implantation%白内障摘出人工晶状体植入术后迟发性葡萄膜炎的临床分析

    Institute of Scientific and Technical Information of China (English)

    赵才; 楚松峰; 王磊

    2011-01-01

    Objective To investigate the pathogenesis and related factors of delayed uveitis after cataract extraction intraocular lens (IOL) implantation surgery.Methods 27 eyes of delayed uveitis in 545 age-related cataract cases,15 cases of delayed uveitis in 92 cases with diabetic cataract,11 cases of delayed uveitis in 73 cases of child and adolescent cataract were retrospectively analyzed.Age-related cataract,diabetic cataract,children cataract were divided into group A,group B and group C.We compared the rates of delayed uveitis of group A with group B,and group A with group C to see if it has statistically significant difference,using statistical methods x2inspection comparison.Results The rates of delayed uveitis between age-related cataract and diabetic cataract was statistically significantly different (P < 0.0l ),the rates of delayed uveitis between age-related cataract and children cataract was statistically significantly different ( P < 0.01 ).Conclusion Diabetes and younger are considered as the factors of delayed uveitis.The prognosis depends on the early treatment.%目的 探讨白内障人工晶体植入术后出现的迟发性葡萄膜炎的发病机制及其相关影响因素.方法 系统性同顾545例(596眼)年龄相关性白内障摘出术后迟发性葡萄膜反应27眼;糖尿病性的白内障92例(92眼),术后迟发性葡萄膜反应15眼;青少年儿童白内障73例(73眼),术后迟发性葡萄膜反应11眼.将年龄相关性白内障、糖尿病性白内障、青少年儿童白内障依次分作A组、B组和C组,比较A组与B组、A组与C组间术后迟发性葡萄膜炎的发病情况差异.结果 年龄相关性白内障术后迟发性葡萄膜反应发生率为4.53%与糖尿病性白内障术后发生率(16.38%)之间差异有统计学意义(P<0.01);与青少年儿童白内障术后发生率(15.07%)之间差异也有统计学意义(P<0.01).结论 青少年儿童白内障、糖尿病性白内障患者人工晶状体植

  4. The Optimal Gravitational Lens Telescope

    CERN Document Server

    Surdej, J; Coleman, P; Dominik, M; Habraken, S; Hanot, C; Coroller, H Le; Mawet, D; Quintana, H; Sadibekova, T; Sluse, D; 10.1088/0004-6256/139/5/1935

    2010-01-01

    Given an observed gravitational lens mirage produced by a foreground deflector (cf. galaxy, quasar, cluster,...), it is possible via numerical lens inversion to retrieve the real source image, taking full advantage of the magnifying power of the cosmic lens. This has been achieved in the past for several remarkable gravitational lens systems. Instead, we propose here to invert an observed multiply imaged source directly at the telescope using an ad-hoc optical instrument which is described in the present paper. Compared to the previous method, this should allow one to detect fainter source features as well as to use such an optimal gravitational lens telescope to explore even fainter objects located behind and near the lens. Laboratory and numerical experiments illustrate this new approach.

  5. Advances in lens implant technology

    OpenAIRE

    Kook, Daniel; Kampik, Anselm; Dexl, Alois K.; Zimmermann, Nicole; Glasser, Adrian; Baumeister, Martin; Kohnen, Thomas

    2013-01-01

    Cataract surgery is one of the oldest and the most frequent outpatient clinic operations in medicine performed worldwide. The clouded human crystalline lens is replaced by an artificial intraocular lens implanted into the capsular bag. During the last six decades, cataract surgery has undergone rapid development from a traumatic, manual surgical procedure with implantation of a simple lens to a minimally invasive intervention increasingly assisted by high technology and a broad variety of imp...

  6. Connexin hemichannels in the lens

    OpenAIRE

    EricCBeyer

    2014-01-01

    The normal function and survival of cells in the avascular lens is facilitated by intercellular communication through an extensive network of gap junctions formed predominantly by three connexins (Cx43, Cx46, and Cx50). In expression systems, these connexins can all induce hemi-channel currents, but other lens proteins (e.g., pannexin1) can also induce similar currents. Hemichannel currents have been detected in isolated lens fiber cells. These hemichannels may make significant contributio...

  7. Connexin hemichannels in the lens

    OpenAIRE

    Beyer, Eric C.; Berthoud, Viviana M.

    2014-01-01

    The normal function and survival of cells in the avascular lens is facilitated by intercellular communication through an extensive network of gap junctions formed predominantly by three connexins (Cx43, Cx46, and Cx50). In expression systems, these connexins can all induce hemichannel currents, but other lens proteins (e.g., pannexin1) can also induce similar currents. Hemichannel currents have been detected in isolated lens fiber cells. These hemichannels may make significant contributions t...

  8. Dispersion-compensated fresnel lens

    Science.gov (United States)

    Johnson, Kenneth C.

    1992-01-01

    A transmission grating is used to reduce chromatic aberration in a Fresnel lens, wherein the lens chromatic dispersion is offset and substantially canceled by the grating's diffraction-induced dispersion. The grating comprises a Fresnel-type pattern of microscopic facets molded directly into the lens surface. The facets would typically have a profile height of around 4.multidot.10.sup.-5 inch and a profile width of at least 10.sup.-3 inch. In its primary intended application, the invention would function to improve the optical performance of a Fresnel lens used to concentrate direct sunlight.

  9. Development of lens sutures.

    Science.gov (United States)

    Kuszak, Jer R; Zoltoski, Rebecca K; Tiedemann, Clifford E

    2004-01-01

    Cylindrical map projections (CMPs) have been used for centuries as an effective means of plotting the features of a 3D spheroidal surfaces (e.g. the earth) on a 2D rectangular map. We have used CMPs to plot primate fiber cell organization from selected growth shells as a function of growth, development and aging. Lens structural parameters and features were derived from slit-lamp, light and transmission and scanning electron micrographs. This information was then used to create CMPs of lenses that were then correlated with azimuthal map projections (AMPs; projections that are radially symmetric around a central point [the poles]) to reveal different suture patterns during distinct time periods. In this manner, both lens fiber and suture branch locations are defined by degrees of longitude and latitude. CMPs and AMPs confirm that throughout defined periods of development, growth and ageing, increasingly complex suture patterns are formed by the precise ordering of straight and opposite end curvature fibers. However, the manner in which additional suture branches are formed anteriorly and posteriorly is not identical. Anteriorly, new branches are added between extant branches. Posteriorly, pairs of new branches are formed that progressively overlay extant branches. The advantage of using CMPs is that the shape and organization of every fiber in a growth shell can be observed in a single image. Thus, the use of CMPs to plot primate fiber cell organization has revealed more complex aspects of fiber formation that may explain, at least in part, changes in lens optical quality as a function of age and pathology. In addition, more accurate measurements of fiber length will be possible by incorporating the latitudinal and longitudinal locations of fibers. PMID:15558480

  10. Lens of Eye Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Mallett, Michael Wesley [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-23

    An analysis of LANL occupational dose measurements was made with respect to lens of eye dose (LOE), in particular, for plutonium workers. Table 1 shows the reported LOE as a ratio of the “deep” (photon only) and “deep+neutron” dose for routine monitored workers at LANL for the past ten years. The data compares the mean and range of these values for plutonium workers* and non-routine plutonium workers. All doses were reported based on measurements with the LANL Model 8823 TLD.

  11. Diffractive Alvarez lens

    International Nuclear Information System (INIS)

    A diffractive Alvarez lens is demonstrated that consists of two separate phase plates, each having complementary 16-level surface-relief profiles that contain cubic phase delays. Translation of these two components in the plane of the phase plates is shown to produce a variable astigmatic focus. Both spherical and cylindrical phase profiles are demonstrated with good accuracy, and the discrete surface-relief features are shown to cause less than λ/10 wave-front aberration in the transmitted wave front over a 40 mmx80 mm region. (c) 2000 Optical Society of America

  12. Media Language, Clear or Obscure

    DEFF Research Database (Denmark)

    Jakobsen, Bjarne le Fevre; Ejstrup, Michael

    2015-01-01

    Abstract— Be clear, not obscure. One of the four maxims for optimal communication is that it is essential to develop proficiency in being concise and clear. The question is whether this is really a good idea in all contexts. There is some evidence to the contrary. Undoubtedly, we have many contex...

  13. Recent Advances in Cataract Operations: Phacoemulsification, Intraocular Lens Implantation and Prolonged-Wear Soft Contact Lenses

    OpenAIRE

    Salz, James J.

    1981-01-01

    A standard cataract extraction involves removal of the entire cataractous lens through a 12- to 13-mm incision with the aid of a cryoprobe while phacoemulsification consists of removing the cataract through a 3-mm incision by breaking the lens into small pieces with an ultrasonically vibrating needle which is then used to aspirate the fragmented cataract. Most ophthalmic surgeons choose to carry out the standard cataract extraction because although phacoemulsification offers a more rapid reha...

  14. Sushruta in 600 B.C. introduced extraocular expulsion of lens material.

    Science.gov (United States)

    Grzybowski, Andrzej; Ascaso, Francisco J

    2014-03-01

    It is generally accepted that Jacques Daviel introduced in the 18th century the extracapsular technique of extraction of the lens while the couching method of cataract operation had already been practiced since ancient times. Present study analyses the first known cataract surgery description in three translations into English from the original Sanskrit Sushruta textbook and all the available literature on the subject. We found evidences that some sort of extraocular expulsion of lens material through a limbal puncture (paracentesis) was described by the Indian surgeon. Nevertheless, this incision cannot be considered as a classic extracapsular procedure because it was not large enough to allow the extraction of the entire lens. PMID:23464869

  15. Clear Cell Basal Cell Carcinoma

    OpenAIRE

    Bo Wang; Tracey Harbert; Jennifer Olivella; Daniel Olson; Sarma, Deba P; Stephanie Ortman

    2011-01-01

    Introduction. Clear cell basal cell carcinoma (BCC) is an uncommon and unusual variant of BCC, which is characterized by a variable component of clear cells. The pathogenesis of this histological variant and its clinical significance has not been clarified. Differentiation of this uncommon variant of BCC from other clear cell tumors is important for the treatment. Case Presentation. A 65-year-old male presented with a 0.9 cm dome-shaped lesion on his upper chest. A shave biopsy revealed a der...

  16. Media Language, Clear or Obscure

    DEFF Research Database (Denmark)

    Ejstrup, Michael; le Fevre Jakobsen, Bjarne

    2015-01-01

    Be clear, not obscure. One of the four maxims for optimal communication is that it is essential to develop proficiency in being concise and clear. The question is whether this is really a good idea in all contexts. There is some evidence to the contrary. Undoubtedly, we have many contexts where it...... is important for mutual understanding that we be clear and concise. This is true of instructions for electronic equipment and for household appliances. Here, linguistic brevity and clarity may be preferable, but not in other cases. Culture, globalization, and the recognition of ever faster growth in...

  17. 77 FR 21277 - Customer Clearing Documentation, Timing of Acceptance for Clearing, and Clearing Member Risk...

    Science.gov (United States)

    2012-04-09

    ... for Processing, Clearing, and Transfer of Customer Positions, 76 FR 13101 (Mar. 10, 2011). \\6... (Aug. 1, 2011). \\11\\ See 76 FR 33066 (Jun. 6, 2011). II. Customer Clearing Documentation A... customer when trading with that SD or MSP. \\12\\ See 76 FR 45730 at 45731, Aug. 1, 2011. \\13\\ See...

  18. Saccadic lens instability increases with accommodative stimulus in presbyopes

    OpenAIRE

    He, Lin; Donnelly, William J.; Stevenson, Scott B.; Glasser, Adrian

    2010-01-01

    An SRI dual Purkinje image (dPi) eye tracker was used to measure lens wobble following saccades with increasing accommodative effort as an indirect measure of ciliary muscle function in presbyopes. Ten presbyopic subjects executed 32 four-degree saccades at 1-s intervals between targets arranged in a cross on illuminated cards at each of 9 viewing distances ranging from 0.5- to 8-D accommodative demands. Post-saccadic lens wobble artifacts were extracted by subtraction of P1 (H1/V1) position ...

  19. The Deep Lens Survey

    CERN Document Server

    Wittman, D; Dell'Antonio, I P; Becker, A C; Margoniner, V E; Cohen, J; Norman, D; Loomba, D; Squires, G; Wilson, G; Stubbs, C; Hennawi, J F; Spergel, D N; Boeshaar, P C; Clocchiatti, A; Hamuy, M; Bernstein, G; González, A; Guhathakurta, R; Hu, W; Seljak, U; Zaritsky, D

    2002-01-01

    The Deep Lens Survey (DLS) is a deep BVRz' imaging survey of seven 2x2 degree fields, with all data to be made public. The primary scientific driver is weak gravitational lensing, but the survey is also designed to enable a wide array of other astrophysical investigations. A unique feature of this survey is the search for transient phenomena. We subtract multiple exposures of a field, detect differences, classify, and release transients on the Web within about an hour of observation. Here we summarize the scientific goals of the DLS, field and filter selection, observing techniques and current status, data reduction, data products and release, and transient detections. Finally, we discuss some lessons which might apply to future large surveys such as LSST.

  20. Flat acoustic lens by acoustic grating with curled slits

    KAUST Repository

    Peng, Pai

    2014-10-01

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

  1. A planar lens based on the electrowetting of two immiscible liquids

    International Nuclear Information System (INIS)

    This paper reports the development and characterization of a planar liquid lens based on electrowetting. The working concept of electrowetting two immiscible liquids is demonstrated with measurement and characterization of contact angles with regard to externally applied electric voltages. Consequently, a planar liquid lens is designed and implemented based on this competitive electrowetting. A droplet of silicone oil confined in an aqueous solution (1% KCl) works as a liquid lens. Electrowetting then controls the shape of the confined silicone oil and the focal length of the liquid lens varies depending upon an applied dc voltage. A unique feature of this lens design is the double-ring planar electrodes beneath the hydrophobic substrate. While an outer ring electrode provides an initial boundary for the silicone oil droplet, an inner ring works as the actuation electrode for the lens. Further, the planar electrodes, instead of vertical or out-of-plane wall electrodes, facilitate the integration of liquid lenses into microfluidic systems. With the voltage applied in the range of 50–250 V, the confined silicone oil droplet changed its shape and the optical magnification of a 3 mm-diameter liquid lens was clearly demonstrated. Moreover, focal lengths of liquid lenses with diameters of 2 mm, 3 mm and 4 mm were characterized, respectively. The obtained results suggest that a larger lens diameter yields a longer focal length and a wider range of focal length change in response to voltage. The demonstrated liquid lens has a simple structure and is easy to fabricate

  2. Photothermal Lens Aberration Effects in Two Laser Thermal Lens Spectrometry

    OpenAIRE

    Bialkowski, Stephen E.

    1985-01-01

    A comparison of theories describing two laser photothermal lens signals is given. The aberrant nature of this lens is accounted for in a theory which treats the propagation of a monitor laser in terms of a phase shift in this laser beam wave front. The difference between theories are discussed in terms of the predicted signal strengths and temporal behavior. The aberrant theory results in smaller theoretical signal strengths and different functional relationships between signal and analyte le...

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

    Science.gov (United States)

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

    2015-06-01

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

  4. An electrostatic deceleration lens for highly charged ions

    International Nuclear Information System (INIS)

    The design and implementation of a purely electrostatic deceleration lens used to obtain beams of highly charged ions at very low energies is presented. The design of the lens is such that it can be used with parallel as well as diverging incoming beams and delivers a well focused low energy beam at the target. In addition, tuning of the final energy of the beam over a wide range (1 eV/q to several hundred eV/q, where q is the beam charge state) is possible without any change in hardware configuration. The deceleration lens was tested with Ar8+, extracted from an electron cyclotron resonance ion source, having an initial energy of 30 keV/q and final energies as low as 70 eV/q have been achieved.

  5. An electrostatic deceleration lens for highly charged ions.

    Science.gov (United States)

    Rajput, J; Roy, A; Kanjilal, D; Ahuja, R; Safvan, C P

    2010-04-01

    The design and implementation of a purely electrostatic deceleration lens used to obtain beams of highly charged ions at very low energies is presented. The design of the lens is such that it can be used with parallel as well as diverging incoming beams and delivers a well focused low energy beam at the target. In addition, tuning of the final energy of the beam over a wide range (1 eV/q to several hundred eV/q, where q is the beam charge state) is possible without any change in hardware configuration. The deceleration lens was tested with Ar(8+), extracted from an electron cyclotron resonance ion source, having an initial energy of 30 keV/q and final energies as low as 70 eV/q have been achieved. PMID:20441330

  6. Lens siderosis resulting from a small intralenticular metallic foreign body

    Directory of Open Access Journals (Sweden)

    Shah, Mehul A.

    2015-11-01

    Full Text Available We report a rare case of lens siderosis with an undetectable intraocular foreign body by imaging. An 8-year-old boy presented with diminution of vision in the left eye since 3 months. His parents gave a preceding uncertain history of a foreign body injury to his left eye 3 months ago while playing. Presenting visual acuity in the left eye was perception of hand movements. Slit-lamp examination revealed a total white cataract with brownish-pigmented spots on the anterior capsule of the lens, but no intraocular foreign body was found. There was also no evidence of an intraocular foreign body on ultrasonography. Patient underwent cataract extraction with intraocular lens implantation. During the operation, a small (2×1×1 mm in size intralenticular foreign body of metal material was found and removed carefully with a magnet. The patient regained 20/30 vision after surgery.

  7. 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.

  8. Lens design based on lens form parameters using Gaussian brackets

    Science.gov (United States)

    Yuan, Xiangyu; Cheng, Xuemin

    2014-11-01

    The optical power distribution and the symmetry of the lens components are two important attributes that decide the ultimate lens performance and characteristics. Lens form parameters W and S are the key criteria describing the two attributes mentioned above. Lens components with smaller W and S will have a good nature of aberration balance and perform well in providing good image quality. Applying the Gaussian brackets, the two lens form parameters and the Seidel Aberration Coefficients are reconstructed. An initial lens structure can be analytically described by simultaneous equations of Seidel Aberration Coefficients and third-order aberration theory. Adding the constraints of parameters W and S in the solving process, a solution with a proper image quality and aberration distribution is achieved. The optical properties and image quality of the system based on the parameters W and S are also analyzed in this article. In the method, the aberration distribution can be controlled to some extent in the beginning of design, so that we can reduce some workload of optimization later.

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

    Science.gov (United States)

    Pierscionek, Barbara K.; Li, Yuebin; Yasseen, Akeel A.; Colhoun, Liza M.; Schachar, Ronald A.; Chen, Wei

    2010-01-01

    There are no treatments for reversing or halting cataract, a disease of the structural proteins in the eye lens, that has associations with other age-related degenerative conditions such as Alzheimer's disease. The incidence of cataract and associated conditions is increasing as the average age of the population rises. Protein folding diseases are difficult to assess in vivo as proteins and their age-related changes are assessed after extraction. Nanotechnology can be used to investigate protein changes in the intact lens as well as for a potential means of drug delivery. Nanoparticles, such as cerium oxide (CeO2) which have antioxidant properties, may even be used as a means of treating cataract directly. Prior to use in treatments, nanoparticle genotoxicity must be tested to assess the extent of any DNA or chromosomal damage. Sister chromatid exchanges were measured and DNA damage investigated using the alkaline COMET assay on cultured human lens epithelial cells, exposed to 5 and 10 µg ml-1 of CeO2 nanoparticles (nanoceria). Nanoceria at these dosages did not cause any DNA damage or significant increases in the number of sister chromatid exchanges. The absence of genotoxic effects on lens cells suggests that nanoceria, in the doses and exposures tested in this study, are not deleterious to the eye lens and have the potential for use in studying structural alterations, in developing non-surgical cataract treatments and in investigating other protein folding diseases.

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

    International Nuclear Information System (INIS)

    There are no treatments for reversing or halting cataract, a disease of the structural proteins in the eye lens, that has associations with other age-related degenerative conditions such as Alzheimer's disease. The incidence of cataract and associated conditions is increasing as the average age of the population rises. Protein folding diseases are difficult to assess in vivo as proteins and their age-related changes are assessed after extraction. Nanotechnology can be used to investigate protein changes in the intact lens as well as for a potential means of drug delivery. Nanoparticles, such as cerium oxide (CeO2) which have antioxidant properties, may even be used as a means of treating cataract directly. Prior to use in treatments, nanoparticle genotoxicity must be tested to assess the extent of any DNA or chromosomal damage. Sister chromatid exchanges were measured and DNA damage investigated using the alkaline COMET assay on cultured human lens epithelial cells, exposed to 5 and 10 μg ml-1 of CeO2 nanoparticles (nanoceria). Nanoceria at these dosages did not cause any DNA damage or significant increases in the number of sister chromatid exchanges. The absence of genotoxic effects on lens cells suggests that nanoceria, in the doses and exposures tested in this study, are not deleterious to the eye lens and have the potential for use in studying structural alterations, in developing non-surgical cataract treatments and in investigating other protein folding diseases.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-22

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

  12. Adjustable hybrid diffractive/refractive achromatic lens

    OpenAIRE

    Valley, Pouria; Savidis, Nickolaos; Schwiegerling, Jim; Dodge, Mohammad Reza; Peyman, Gholam; N. Peyghambarian

    2011-01-01

    We demonstrate a variable focal length achromatic lens that consists of a flat liquid crystal diffractive lens and a pressure-controlled fluidic refractive lens. The diffractive lens is composed of a flat binary Fresnel zone structure and a thin liquid crystal layer, producing high efficiency and millisecond switching times while applying a low ac voltage input. The focusing power of the diffractive lens is adjusted by electrically modifying the sub-zones and re-establishing phase wrapping po...

  13. Refractive lens for hard x-rays

    International Nuclear Information System (INIS)

    The refractive lens for hard X-rays on the base of glass capillary is presented. The fabrication techniques for lens production are described. The model of refractive lens for hard X-ray is proposed. The model assume that the compound lens work similar one thin lens the complex refraction index of which is following: n=1-δ N + i β N. On the base of this model the parameters of focussed beam are calculated and the images of object are constructed

  14. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; P Agarwal

    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...

  15. Inverse Design of Electron Lens

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The inverae design of electron lens is reelized by two different methods in this paper. One isdamped leastsquare method and the other is the artificial neural network method. Their merits and defects are discussed accordingto our calculation results in the psper. In the condition of selecting the learning samples properly, the artificial neuralnetwork has obvious advantages in the inverse design of electron lens. It is an effective method to solve the inversedesign problem in the electron optic system.

  16. Plain Language Clear and Simple.

    Science.gov (United States)

    National Literacy Secretariat, Ottawa (Ontario).

    Written for Canadian public servants and written with their help, this handbook presents principles and tips to make official writing clear, concise, and well organized. The handbook defines "plain language" writing as a technique of organizing information in ways that make sense to the reader--using familiar, straightforward words. The handbook…

  17. 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...

  18. Gabor lens theory

    International Nuclear Information System (INIS)

    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

  19. Melatonin and Sleep-Wake Rhythms before and after Ocular Lens Replacement in Elderly Humans.

    Science.gov (United States)

    Giménez, Marina; Beersma, Domien; Daan, Serge; Pol, Bert van der; Kanis, Martijn; van Norren, Dick; Gordijn, Marijke

    2016-01-01

    Light of short wavelengths has been shown to play a key role in non-image forming responses. Due to aging, the ocular lens becomes more yellow reducing the transmission of short wavelengths in the elderly. In the present study, we make use of cataract surgery to investigate the effects of a relative increase of short wavelength transmission on melatonin- and sleep-wake rhythms (N = 14). We observed, on average, a delay of the sleep-wake and the nocturnal melatonin rhythms after cataract surgery. This delay is tentatively attributed to a relatively large increase of light transmittance in the evening hours more than an increase of the already relatively high light intensities found in the daytime. The later phase that we observed after cataract surgery (clear lens) as compared to the earlier phase observed before cataract (yellowish lens) is in agreement with the general later phase reported in the young (clear lens) population. PMID:26891336

  20. Melatonin and Sleep-Wake Rhythms before and after Ocular Lens Replacement in Elderly Humans

    Directory of Open Access Journals (Sweden)

    Marina Giménez

    2016-02-01

    Full Text Available Light of short wavelengths has been shown to play a key role in non-image forming responses. Due to aging, the ocular lens becomes more yellow reducing the transmission of short wavelengths in the elderly. In the present study, we make use of cataract surgery to investigate the effects of a relative increase of short wavelength transmission on melatonin- and sleep-wake rhythms (N = 14. We observed, on average, a delay of the sleep-wake and the nocturnal melatonin rhythms after cataract surgery. This delay is tentatively attributed to a relatively large increase of light transmittance in the evening hours more than an increase of the already relatively high light intensities found in the daytime. The later phase that we observed after cataract surgery (clear lens as compared to the earlier phase observed before cataract (yellowish lens is in agreement with the general later phase reported in the young (clear lens population.

  1. The art of thinking clearly

    CERN Document Server

    Dobelli, Rolf

    2013-01-01

    The Art of Thinking Clearly by world-class thinker and entrepreneur Rolf Dobelli is an eye-opening look at human psychology and reasoning — essential reading for anyone who wants to avoid “cognitive errors” and make better choices in all aspects of their lives. Have you ever: Invested time in something that, with hindsight, just wasn’t worth it? Or continued doing something you knew was bad for you? These are examples of cognitive biases, simple errors we all make in our day-to-day thinking. But by knowing what they are and how to spot them, we can avoid them and make better decisions. Simple, clear, and always surprising, this indispensable book will change the way you think and transform your decision-making—work, at home, every day. It reveals, in 99 short chapters, the most common errors of judgment, and how to avoid them.

  2. High-resolution phase imaging of phase singularities in the focal region of a lens

    Science.gov (United States)

    Walford, J. N.; Nugent, K. A.; Roberts, A.; Scholten, R. E.

    2002-03-01

    Subwavelength-resolution phase images of phase dislocations at the focal region of a 20×, 0.4-N.A. lens have been obtained by use of an optical fiber interferometer with a tapered probe in one arm. A phase-stepping algorithm is used to determine a quantitative value of the phase at each point in the scan, clearly showing the presence of edge dislocations between the Airy rings of the diffraction pattern near the lens focus, as well as four isolated screw-type singularties caused by astigmatism in the lens.

  3. Biometry of the crystalline lens in late onset diabetes: the importance of diabetic type.

    OpenAIRE

    Sparrow, J M; Bron, A J; Phelps Brown, N A; Neil, H A

    1992-01-01

    Lenticular and anterior chamber biometry were studied in non-cataractous eyes by means of Scheimpflug photography and digital image analysis. The study population consisted of 91 late onset diabetic subjects and 115 non-diabetic controls. Anteroposterior axial lens thickness, cortical thickness, nuclear thickness, anterior clear zone thickness, anterior chamber depth, and anterior and posterior lenticular curvatures were assessed. Age played an important role in determining lens biometry in a...

  4. The effect of gain saturation in a gain compensated perfect lens

    CERN Document Server

    Andresen, Marte P Hatlo; Haakestad, Magnus W; Krogstad, Harald E; Skaar, Johannes

    2010-01-01

    The transmission of evanescent waves in a gain-compensated perfect lens is discussed. In particular, the impact of gain saturation is included in the analysis, and a method for calculating the fields of such nonlinear systems is developed. Gain compensation clearly improves the resolution; however, a number of nonideal effects arise as a result of gain saturation. The resolution associated with the lens is strongly dependent on the saturation constant of the active medium.

  5. Pharmacognostic evaluation of Lens culinaris Medikus seeds

    Institute of Scientific and Technical Information of China (English)

    Kripi Vohra; Vivek Kumar Gupta

    2012-01-01

    Objective: To present a detailed pharmacognostic study of the Lens culinaris Medikus (Fabaceae) seeds, a food grain used as Dhal in India. Methods: The macroscopy, microscopy, fluorescence analysis of powdered drug, physicochemical analysis, preliminary testing and other WHO recommended methods for standardization were investigated. Results: Seeds are greyish brown in colour. Treatment of powdered drug with various chemical reagents showed the presence of proteins, cellulose, lignins and fixed oils. Microscopy of seeds revealed the presence of starch grains in seed. The colour of seed coat changed from brown to greenish grey in day light and brown to black at 254nm when treated with acetic acid. Total ash value of the seeds was found to be 1.86% w/w whereas foreign organic matter was found to be nil. Qualitative phytochemical analysis revealed the presence of tannins and flavonoids in acetone extract. Conclusions: The present study on pharmacognostic profile of Lens culinaris Medikus seeds provides an important tool in identification and authentication of this plant to researchers in future.

  6. Lens Epithelial Cell Proliferation and Cell Density in Human Age-related Cataract

    Institute of Scientific and Technical Information of China (English)

    Xialin Liu; Yizhi Liu; Jianliang Zheng; Qiang Huang; Huling Zheng

    2000-01-01

    Purpose: To discuss the potential effect of the lens epithelial cell proliferation in age-related cataract.Methods: In vitro cell proliferation was assayed by MTT method to evaluate the lens epithelial cell density, index, and proliferation capacity in normal lens and all kinds of age-related cataract. Capsulotomy specimens from all kinds of patients who underwent cataract phacoemulsification extraction surgery were compared with the lens epithelial specimens from non-cataract lenses of Eye Bank eyes.Results: Lens epithelial cell density of central anterior capsule (LECD) in female normal lens was higher than that in male, LECD in nuclear cataract( > NⅢ ) was higher than that in normal lens, but in the mature cortical cataract, LF CD was lower. Mitotic index of three kinds of age-related cataracts in vivo had no statistical difference, neither did cell proliferation capacity of cultivated cells in vitro.Conclusion: The individual difference of lens epithelial cell density and proliferation capacity in vivo may be an important underlying cause for senile cataract in the cellular level, especially for nuclear cataract.

  7. Kataract Phacoemulsification in the Treatment of Patients with Combined Lens Pathology

    Directory of Open Access Journals (Sweden)

    Smetankin I.G.

    2011-09-01

    Full Text Available There have been discussed present principles and strategic approaches in cataract treatment in patients with combined lens pathology (glaucoma, pseudoexfoliative syndrome, lens subluxation, syndrome of rigid iris as the most troublesome group of patients whose frequency of intra- and postoperative complications after cataract extraction has remained relatively high. Turn to extracapsular phacoemulsification of lens contributes to reduction of complication rate in this group of patients though does not make it possible to exclude them completely. There has been given the review of current techniques and some technical aspects of cataract surgical treatment, and have been drawn up the ways to improve the technology phacoemulsification in this complicated group of patients.

  8. Central Clearing of OTC Derivatives

    DEFF Research Database (Denmark)

    Cont, Rama; Kokholm, Thomas

    2014-01-01

    netting agreements. When a CCP exists for interest rate derivatives, adding a CCP for credit derivatives is shown to decrease overall exposures. These findings are shown to be robust to the statistical assumptions of the model as well as the choice of risk measure used to quantify exposures....... classes are realistically taken into account. We argue that empirically plausible specifications of model parameters lead to the conclusion that central clearing does reduce interdealer exposures: the gain from multilateral netting in a CCP overweighs the loss of netting across asset classes in bilateral...

  9. 23-gauge pars plana vitrectomy for management of posteriorly dislocated crystalline lens

    OpenAIRE

    Cho M; Chan RVP

    2011-01-01

    Minhee Cho, RV Paul ChanWeill Cornell Medical College, Department of Ophthalmology, New York, NY, USAPurpose: Management of posteriorly dislocated crystalline lens has traditionally been performed with a standard 20-gauge vitrectomy system. This study demonstrates the use of a 23-gauge vitrectomy system for removal of retained lens fragments secondary to spontaneous dislocation or complicated cataract extraction.Methods: A retrospective, noncomparative, interventional consecutive case series ...

  10. Quantification of individual proteins in silicone hydrogel contact lens deposits

    OpenAIRE

    Omali, Negar Babaei; Zhao, Zhenjun; Zhu, Hua; Tilia, Daniel; Willcox, Mark D.P.

    2013-01-01

    Purpose The aim of this study was to quantify specific proteins deposited on daily wear silicone hydrogel lenses used in combination with multipurpose disinfecting solutions (MPDSs) by applying multiple-reaction-monitoring mass spectrometry (MRM-MS). Methods Balafilcon A or senofilcon A contact lenses used with different MPDSs on a daily wear schedule were collected. Each worn lens was extracted and then digested with trypsin. MRM-MS was applied to quantify the amounts of lysozyme, lactoferri...

  11. Large scale water lens for solar concentration.

    Science.gov (United States)

    Mondol, A S; Vogel, B; Bastian, G

    2015-06-01

    Properties of large scale water lenses for solar concentration were investigated. These lenses were built from readily available materials, normal tap water and hyper-elastic linear low density polyethylene foil. Exposed to sunlight, the focal lengths and light intensities in the focal spot were measured and calculated. Their optical properties were modeled with a raytracing software based on the lens shape. We have achieved a good match of experimental and theoretical data by considering wavelength dependent concentration factor, absorption and focal length. The change in light concentration as a function of water volume was examined via the resulting load on the foil and the corresponding change of shape. The latter was extracted from images and modeled by a finite element simulation. PMID:26072893

  12. Planar immersion lens with metasurfaces

    CERN Document Server

    Ho, John S; Tanabe, Yuji; Yeh, Alexander J; Fan, Shanhui; Poon, Ada S Y

    2015-01-01

    The solid immersion lens is a powerful optical tool that allows light entering material from air or vacuum to focus to a spot much smaller than the free-space wavelength. Conventionally, however, they rely on semispherical topographies and are non-planar and bulky, which limits their integration in many applications. Recently, there has been considerable interest in using planar structures, referred to as metasurfaces, to construct flat optical components for manipulating light in unusual ways. Here, we propose and demonstrate the concept of a planar immersion lens based on metasurfaces. The resulting planar device, when placed near an interface between air and dielectric material, can focus electromagnetic radiation incident from air to a spot in material smaller than the free-space wavelength. As an experimental demonstration, we fabricate an ultrathin and flexible microwave lens and further show that it achieves wireless energy transfer in material mimicking biological tissue.

  13. Intraocular camera for retinal prostheses: Refractive and diffractive lens systems

    Science.gov (United States)

    Hauer, Michelle Christine

    The focus of this thesis is on the design and analysis of refractive, diffractive, and hybrid refractive/diffractive lens systems for a miniaturized camera that can be surgically implanted in the crystalline lens sac and is designed to work in conjunction with current and future generation retinal prostheses. The development of such an intraocular camera (IOC) would eliminate the need for an external head-mounted or eyeglass-mounted camera. Placing the camera inside the eye would allow subjects to use their natural eye movements for foveation (attention) instead of more cumbersome head tracking, would notably aid in personal navigation and mobility, and would also be significantly more psychologically appealing from the standpoint of personal appearances. The capability for accommodation with no moving parts or feedback control is incorporated by employing camera designs that exhibit nearly infinite depth of field. Such an ultracompact optical imaging system requires a unique combination of refractive and diffractive optical elements and relaxed system constraints derived from human psychophysics. This configuration necessitates an extremely compact, short focal-length lens system with an f-number close to unity. Initially, these constraints appear highly aggressive from an optical design perspective. However, after careful analysis of the unique imaging requirements of a camera intended to work in conjunction with the relatively low pixellation levels of a retinal microstimulator array, it becomes clear that such a design is not only feasible, but could possibly be implemented with a single lens system.

  14. Development of a novel mixed hemimicelles dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene for the separation and preconcentration of fluoxetine in different matrices before its determination by fiber optic linear array spectrophotometry and mode-mismatched thermal lens spectroscopy.

    Science.gov (United States)

    Kazemi, Elahe; Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh; Abbasi, Amir; Rashidian Vaziri, Mohammad Reza; Behjat, Abbas

    2016-01-28

    This study aims at developing a novel, sensitive, fast, simple and convenient method for separation and preconcentration of trace amounts of fluoxetine before its spectrophotometric determination. The method is based on combination of magnetic mixed hemimicelles solid phase extraction and dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene as a sorbent. The magnetic graphene was synthesized by a simple coprecipitation method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The retained analyte was eluted using a 100 μL mixture of methanol/acetic acid (9:1) and converted into fluoxetine-β-cyclodextrin inclusion complex. The analyte was then quantified by fiber optic linear array spectrophotometry as well as mode-mismatched thermal lens spectroscopy (TLS). The factors affecting the separation, preconcentration and determination of fluoxetine were investigated and optimized. With a 50 mL sample and under optimized conditions using the spectrophotometry technique, the method exhibited a linear dynamic range of 0.4-60.0 μg L(-1), a detection limit of 0.21 μg L(-1), an enrichment factor of 167, and a relative standard deviation of 2.1% and 3.8% (n = 6) at 60 μg L(-1) level of fluoxetine for intra- and inter-day analyses, respectively. However, with thermal lens spectrometry and a sample volume of 10 mL, the method exhibited a linear dynamic range of 0.05-300 μg L(-1), a detection limit of 0.016 μg L(-1) and a relative standard deviation of 3.8% and 5.6% (n = 6) at 60 μg L(-1) level of fluoxetine for intra- and inter-day analyses, respectively. The method was successfully applied to determine fluoxetine in pharmaceutical formulation, human urine and environmental water samples. PMID:26755141

  15. Clearing and Labeling Techniques for Large-Scale Biological Tissues.

    Science.gov (United States)

    Seo, Jinyoung; Choe, Minjin; Kim, Sung-Yon

    2016-06-30

    Clearing and labeling techniques for large-scale biological tissues enable simultaneous extraction of molecular and structural information with minimal disassembly of the sample, facilitating the integration of molecular, cellular and systems biology across different scales. Recent years have witnessed an explosive increase in the number of such methods and their applications, reflecting heightened interest in organ-wide clearing and labeling across many fields of biology and medicine. In this review, we provide an overview and comparison of existing clearing and labeling techniques and discuss challenges and opportunities in the investigations of large-scale biological systems. PMID:27239813

  16. A broadband transformation-optics metasurface lens

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Xiang; Xiang Jiang, Wei; Feng Ma, Hui; Jun Cui, Tie, E-mail: tjcui@seu.edu.cn [State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096 (China)

    2014-04-14

    We present a transformational metasurface Luneburg lens based on the quasi-conformal mapping method, which has weakly anisotropic constitutive parameters. We design the metasurface lens using inhomogeneous artificial structures to realize the required surface refractive indexes. The transformational metasurface Luneburg lens is fabricated and the measurement results demonstrate very good performance in controlling the radiated surface waves.

  17. 21 CFR 886.3600 - Intraocular lens.

    Science.gov (United States)

    2010-04-01

    ... the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens. 886.3600 Section 886.3600 Food... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification....

  18. 21 CFR 886.1400 - Maddox lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Maddox lens. 886.1400 Section 886.1400 Food and... OPHTHALMIC DEVICES Diagnostic Devices § 886.1400 Maddox lens. (a) Identification. A Maddox lens is a device... intended to be handheld or placed in a trial frame to evaluate eye muscle dysfunction. (b)...

  19. Diabetes and contact lens wear.

    Science.gov (United States)

    O'Donnell, Clare; Efron, Nathan

    2012-05-01

    The literature suggests that diabetic patients may have altered tear chemistry and tear secretion as well as structural and functional changes to the corneal epithelium, endothelium and nerves. These factors, together with a reported increased incidence of corneal infection, suggest that diabetic patients may be particularly susceptible to developing ocular complications during contact lens wear. Reports of contact lens-induced complications in diabetic patients do exist, although a number of these reports concern patients with advanced diabetic eye disease using lenses on an extended wear basis. Over the past decade or so, there have been published studies documenting the response of the diabetic eye to more modern contact lens modalities. The results of these studies suggest that contact lenses can be a viable mode of refractive correction for diabetic patients. Furthermore, new research suggests that the measurement of tear glucose concentration could, in future, be used to monitor metabolic control non-invasively in diabetic patients. This could be carried out using contact lenses manufactured from hydrogel polymers embedded with glucose-sensing agents or nanoscale digital electronic technology. The purpose of this paper is to review the literature on the anterior ocular manifestations of diabetes, particularly that pertaining to contact lens wear. PMID:22537249

  20. The ClearPET project

    International Nuclear Information System (INIS)

    The Crystal Clear Collaboration has designed and is building a high-resolution small animal PET scanner. The design is based on the use of the Hamamatsu R7600-M64 multi-anode photomultiplier tube and a LSO/LuYAP phoswich matrix with one to one coupling between the crystals and the photo-detector. The complete system will have 80 PM tubes in four rings with an inner diameter of 137 mm and an axial field of view of 110 mm. The PM pulses are digitized by free-running ADCs and digital data processing determines the gamma energy, the phoswich layer and even the pulse arrival time. Single gamma interactions are recorded and coincidences are found by software. The gantry allows rotation of the detector modules around the field of view. Simulations, and measurements a 2x4 module test set-up predict a spatial resolution of 1.5 mm in the centre of the field of view and a sensitivity of 5.9% for a point source in the centre of the field of view

  1. Radiation damage of the lens

    International Nuclear Information System (INIS)

    Explained is the cataract as the lens is one of the most sensitive tissues to radiation, for considering the possible ophthalmological radiation disorder by the Fukushima Nuclear Power Plant Accident (2011). Radiation cataract is observed at 1-2 years after acute high dose exposure, but at low dose, it appears as the late effect. In fact, the disease related to exposure is found in as many as 25% of Chernobyl workers at >10 years post its Accident. Pathologic feature of radiation cataract has been thought to be the posterior subcapsular type. However, the cortical type is shown to be also noted by recent findings in the Chernobyl Accident, in the lens 30-45 years after radiotherapy of infants for dermovascular angioma, in astronaut, and in Hiroshima A-bomb survivors. Acute exposure to 0.5-1.5 Gy results in lens opacity and at >5 Gy, cataract with visual dysfunction. Higher cataract prevalence is recently reported seen in the therapeutic cardiac fluoroscopy where the medians of accumulated doses are 6.0 Sv in doctors and 1.5 Sv in nurses and radiologists. Astronauts exposed at >8 mSv have higher prevalence. Animal experiments have shown that the lens sensitivity to radiation depends on the age. Clinical experience of radiotherapy of the angioma above has suggested the higher sensitivity in young generation, which is supported by the fact that, among 114 inhabitants of 60Co-contaminated building, the dose effect is observable in 61 inhabitants of the age <20 y alone. linear threshold theory (LNT) hypothesis cannot be excluded by above evidences and there is conceivably no (or extremely low) threshold for cataract. The younger the age of exposure, the higher the risk of cataract, and thereby the lens in young generation should be carefully followed-up in Fukushima. (T.T.)

  2. MI Gap Clearing Kicker Magnet Design Review

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Chris; /Fermilab

    2008-10-01

    The kicker system requirements were originally conceived for the NOvA project. NOvA is a neutrino experiment located in Minnesota. To achieve the desired neutrino flux several upgrades are required to the accelerator complex. The Recycler will be used as a proton pre-injector for the Main Injector (MI). As the Recycler is the same size as the MI, it is possible to do a single turn fill ({approx}11 {micro}sec), minimizing the proton injection time in the MI cycle and maximizing the protons on target. The Recycler can then be filled with beam while the MI is ramping to extract beam to the target. To do this requires two new transfer lines. The existing Recycler injection line was designed for 10{pi} pbar beams, not the 20{pi} proton beams we anticipate from the Booster. The existing Recycler extraction line allows for proton injection through the MI, while we want direct injection from the Booster. These two lines will be decommissioned. The new injection line from the MI8 line into the Recycler will start at 848 and end with injection kickers at RR104. The new extraction line in the RR30 straight section will start with a new extraction kicker at RR232 and end with new MI injection kickers at MI308. Finally, to reduce beam loss activation in the enclosure, a new gap clearing kicker will be used to extract uncaptured beam created during the slip stack injection process down the existing dump line. It was suggested that the MI could benefit from this type of system immediately. This led to the early installation of the gap clearing system in the MI, followed by moving the system to Recycler during NOvA. The specifications also changed during this process. Initially the rise and fall time requirements were 38 ns and the field stability was {+-}1%. The 38 ns is based on having a gap of 2 RF buckets between injections. (There are 84 RF buckets that can be filled from the Booster for each injection, but 82 would be filled with beam. MI and Recycler contain 588 RF buckets

  3. Sequential Application of Glass Coverslips to Assess the Compressive Stiffness of the Mouse Lens: Strain and Morphometric Analyses.

    Science.gov (United States)

    Cheng, Catherine; Gokhin, David S; Nowak, Roberta B; Fowler, Velia M

    2016-01-01

    The eye lens is a transparent organ that refracts and focuses light to form a clear image on the retina. In humans, ciliary muscles contract to deform the lens, leading to an increase in the lens' optical power to focus on nearby objects, a process known as accommodation. Age-related changes in lens stiffness have been linked to presbyopia, a reduction in the lens' ability to accommodate, and, by extension, the need for reading glasses. Even though mouse lenses do not accommodate or develop presbyopia, mouse models can provide an invaluable genetic tool for understanding lens pathologies, and the accelerated aging observed in mice enables the study of age-related changes in the lens. This protocol demonstrates a simple, precise, and cost-effective method for determining mouse lens stiffness, using glass coverslips to apply sequentially increasing compressive loads onto the lens. Representative data confirm that mouse lenses become stiffer with age, like human lenses. This method is highly reproducible and can potentially be scaled up to mechanically test lenses from larger animals. PMID:27166880

  4. 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

  5. Micro-optic lens for data storage

    Science.gov (United States)

    Milster, T. D.; Trusty, R. M.; Wang, M. S.; Froehlich, F. F.; Erwin, J. Kevin

    1991-01-01

    A new type of microlens for data storage applications that has improved off-axis performance is described. The lens consists of a micro Fresnel pattern on a curved substrate. The radius of the substrate is equal to the focal length of the lens. If the pattern and substrate are thin, the combination satisfies the Abbe sine condition. Therefore, the lens is free of coma. We analyze a 0.5 numerical aperture, 0.50 mm focal length lens in detail. A 0.16 numerical aperture lens was fabricated holographically, and results are presented.

  6. Lactate Dehydrogenase Isoenzyme of Lens in Fetus

    Institute of Scientific and Technical Information of China (English)

    Kexi Ding; Yasong Zhang

    2002-01-01

    Purpose: The LDH isoenzyme patterns were evaluated in lens of fetus to study the metabolism in human lenses.Methods: LDH isoenzyme electrophoresis was performed in 15 lenses of human fetus aged from 4~6 months.Results: There are 5 bands of LDH in fetus lens. LDH4 lever is the highest, and LDH1 is the lowest, especially in the cortex of lens. LDH1 is higher in lens of 4 months of age than in that of 5 and 6 months of age.Conclusions: LDH isoenzyme in lens of fetus shows mainly anaerobic metabolism in development, but there is also aerobic metabolism, especially in younger fetus.

  7. Conjunctival impression cytology in contact lens wearers.

    Directory of Open Access Journals (Sweden)

    Simon Priya

    2002-01-01

    Full Text Available PURPOSE: To evaluate the cytological changes in conjunctiva following regular contact lens wear and to determine the correlation, if any, between severity of cytological alteration and symptoms related to contact lens wear. METHODS: One hundred eyes (50 normal asymptomatic subjects who served as a control group were studied by conjunctival impression cytology (CIC. These subjects were fitted with rigid gas permeable (RGP or soft contact lenses and were followed up at the end of 3 and 6 months. At each follow-up visit the CIC was repeated. A filter paper with the impression specimen was stained with periodic acid schiff (PAS and haematoxylin stain to study goblet cell loss. Papanicolaou stain was done to study squamous metaplasia. The cytological changes were graded using the system described by Natadisastra et al. RESULTS: Severity of cytological changes increased with the duration of contact lens wear (P = 0.00001. At the end of 6 months, 60% of symptomatic eyes wearing soft contact lens and RGP lens showed abnormal CIC changes. None of the asymptomatic RGP contact lens wearing eyes showed abnormal CIC changes whereas 33.4% of the asymptomatic soft contact lens wearing eyes showed abnormal CIC changes (P = 0.033. Epithelial changes occurred within 3-6 months of contact lens fitting. CONCLUSION: Severity of cytological changes increased with duration of lens wear (P = 0.00001. Prevalence and severity of cytological alteration is more in symptomatic contact lens wearers. Soft contact lens wearers although asymptomatic showed severe CIC changes.

  8. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    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

  9. Contact lens surface by electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jung Hyuck [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin [Dongshin Univ., Naju (Korea, Republic of)

    2011-07-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility.

  10. Biomimetic accommodating lens with implementation in MEMS

    Science.gov (United States)

    Hogan, Alexander L.; Baker, Brian; Fisher, Charles; Naylor, Stephen; Fettig, Doug; Harvey, Ian R.

    2012-03-01

    We describe an accommodating lens patterned after the crystalline lens of the eye. Our biomimetic MEMS design calls to mind the zonules of zinn which pull radially to stretch the crystalline lens of the eye to modify the optical path. We present initial characterization of the prototype macro-scale device constructed through traditional machining techniques and using a PDMS polymer lens. Testing of the macro-scale lens indicated a 22% change in focal length through the range of radial stretching, with degradation of the spherical lens shape but no hysteresis after low-cycle testing. We also demonstrate a MEMS implementation of the lens actuator constructed using the Sandia SUMMiT-V ™ surface micromachining process. The optical path of this system is approximately 300 microns in diameter, providing a platform to potential applications improving mobile camera optics and medical imaging.

  11. Liquid scintillation counting of 3H-thymidine incorporated into rat lens DNA

    International Nuclear Information System (INIS)

    DNA synthesis in the lens has previously been localized by autoradiography following incorporation of 3H-thymidine. For the quantification of DNA synthesis in the lens, pooling of lenses and extraction of the DNA for liquid scintillation counting, has formerly been adapted. In the present investigation a method has been developed for the extraction of the unincorporated tracer from whole lenses after short time incubation in a medium containing 3H-thymidine. The 3H-thymidine incorporated into individual lenses was then detected by liquid scintillation counting after dissolution of the lenses. The sources of the variation in the method are evaluated. (author)

  12. 非洲贫困地区小切口白内障囊外摘出联合人工晶状体植入术的临床分析%Clinical analysis of small incision extracapsular cataract extraction and intraocular lens implantation in poverty-stricken areas in Africa

    Institute of Scientific and Technical Information of China (English)

    唐建明

    2012-01-01

    Objective To investigate the small incision extracapsular cataract extraction and intraocular lens implantation in the clinical effect and feasibility of poverty-stricken areas of Africa.Methods During the foreign aid in Moroccan from march 2009 to march 2011,the age of 45 to 86-year-old Moroccan patients with 538 cases (580 eyes) had undergone small incision extracapsular cataract extraction and intraocular lens implantation.The visual acuity,postoperative complications were observed.Results Visual acuity of1.0 or more were obtained in 25 eyes (4.31%),0.6~1.0in 148 eyes (25.52%),0.3 ~0.5 in 328 eyes (56.55%),0.05 ~0.25 in 74 eyes (12.76%),<0.05 in 5 eyes (0.86%).Literacy rate was 99.14%,removing residual was 86.38%.Intraoperative complications:iris prolapse 23 eyes (3.97%) ; posterior capsular rupture 33 eyes (5.69%),among which 28 eyes were applied posterior chamber intraocular lens implantation at stage Ⅰ,two cases at stage Ⅱ,the other three eases gave up implantation.Postoperative complications:corneal edema,opacity 21 eyes (3.62%),no corneal bullae or corneal decompensation occurred.Anterior chamber inflammatory response 51 eyes (8.79%).Late-onset uveitis 11 eyes,of which 9 related to diabetes.All patients were found no retinal detachment,secondary glaucoma,intraocular lens dislocation or endophthalmitis.Conclusion Small incision extracapsular cataract extraction with IOL implantation in the joint damage,quick recovery,easy to operate,low cost,suitable for the hospital,poor economic conditions,the places and people,it become possible to make the local poor people cataract bright.%目的 探讨在援非工作过程中进行小切口白内障囊外摘出联合人工晶状体植入术的手术效果与可行性.方法 2009年3月至2011年3月作者在援非期间对年龄45 ~ 86岁的摩洛哥患者538人(580眼)进行小切口白内障囊外摘出联合人工晶状体植入术,并对术后视力、术后并发症的

  13. Charting paths through gravity's lens

    International Nuclear Information System (INIS)

    Features of gravitational lenses are described, together with several examples of seemingly identical celestial objects which were later proved to be the same object. The first evidence was concerned with the object 0957+561, which featured two quasars 6 arcsec apart that displayed equal redshifts, magnitudes, and recession velocities, while the northern component exhibited 30 percent weaker emission and absorption. It was suggested that a galaxy interposed between the earth and a quasar was deflecting its emissions and causing it to be viewed as two distinct objects, i.e., a gravitational lens existed. Later evidence for the intervening galaxy was found, and also permitted attributing the anomalous redshift observed to a contribution from the galaxy. The light bending effect is predicted by the General Theory of Relativity, and is illustated in terms of a point mass, convex lens, and a galaxy

  14. Lens transglutaminase and cataract formation.

    OpenAIRE

    Lorand, L.; Hsu, L K; Siefring, G E; Rafferty, N S

    1981-01-01

    A protein polymer characteristically present in human cataract was shown to contain significant amounts of gamma-glutamyl-epsilon-lysine isopeptides. It is proposed that these crosslinks are produced by the action of transglutaminase (R-glutaminyl-peptide:amine-gamma-glutamyl-yltransferase, EC 2.3.2.13), which is all the more plausible because lens contains the enzyme and endogenous protein substrates for it. The enzyme is similar to that obtained from liver and is Ca2+ dependent. Highest app...

  15. Lens Coupled Quantum Cascade Laser

    Science.gov (United States)

    Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor)

    2013-01-01

    Terahertz quantum cascade (QC) devices are disclosed that can operate, e.g., in a range of about 1 THz to about 10 THz. In some embodiments, QC lasers are disclosed in which an optical element (e.g., a lens) is coupled to an output facet of the laser's active region to enhance coupling of the lasing radiation from the active region to an external environment. In other embodiments, terahertz amplifier and tunable terahertz QC lasers are disclosed.

  16. Fresnel Lens with Embedded Vortices

    OpenAIRE

    Sunil Vyas; Rakesh Kumar Singh; Devinder Pal Ghai; Senthilkumaran, P.

    2012-01-01

    Vortices of different charges are embedded in a wavefront that has quadratic phase variation, and the intensity distribution near the focal plane is studied. This method may be useful in realizing complicated beam profiles. We have experimentally demonstrated the generation of vortex arrays having integer as well as fractional topological charges that produce different intensity profiles at the focal plane. The phase variation realized on a spatial light modulator (SLM) acts as a Fresnel lens...

  17. Cataract extraction with erisophake.

    Science.gov (United States)

    ALEXANDER, H B

    1951-01-01

    Today the erisophake offers the most successful means for the intracapsular extraction of cataracts. The advantages of this method are that no counterpressure is required so that the incidence of vitreous loss is reduced; the vacuum cup provides a firmer grasp of the lens with less danger of rupture of the lens capsule; and the vacuum cup can be used for the delivery of practically all types of cataract in the adult, including intumescent and Morgagnian cataracts as well as lenses with exfoliating and friable capsules. While the forceps method of intracapsular extraction is generally successful in not more than 70 to 75 per cent of cases, the erisophake may offer success in 90 per cent of cases. PMID:14792378

  18. Commercially available rigid gas-permeable contact lens for protecting the cornea from drying during vitrectomy with a wide viewing system

    Directory of Open Access Journals (Sweden)

    Kamei M

    2012-08-01

    Full Text Available Motohiro Kamei, Nagakazu Matsumura, Hirokazu Sakaguchi, Yusuke Oshima, Yasushi Ikuno, Kohji NishidaDepartment of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, JapanPurpose: We evaluated the usefulness of commercially available materials for protecting the cornea from drying during vitrectomy with a wide-angle viewing system.Methods: Three vitreoretinal surgeons evaluated fundus visibility during vitrectomy on the images of five study materials used on the cornea: balanced saline solution, a viscoelastic agent, a vitrectomy contact lens, a rigid gas permeable (RGP contact lens, and a soft contact lens. Fundus visibility was graded using the following scale: grade 1, unclear; grade 2, slightly unclear; grade 3, clear; and grade 4, very clear.Results: Respective scores for each material used during core vitrectomy and membrane removal were: balanced saline solution, 3.3/3.3; viscoelastic agent, 3.8/3.3; vitrectomy contact lens, 3.3/4.0; RGP contact lens, 4.0/3.9; soft contact lens, 1.1/not applicable.Conclusion: The RGP contact lens provided visibility similar to or clearer than that obtained with other methods. Because of its ease of use and lower cost, use of the RGP contact lens is ideal during vitrectomy performed with a wide-angle viewing system.Keywords: contact lens, RGP, viscoelastic agent, vitrectomy, wide viewing system

  19. Adaptive liquid lens driven by elastomer actuator

    Science.gov (United States)

    Jin, Boya; Lee, Ji-Hyeon; Zhou, Zuowei; Zhang, Guoqing; Lee, Gi-Bbeum; Ren, Hongwen; Nah, Changwoon

    2016-01-01

    When a liquid droplet is filled in the hole of a dielectric elastomer (DE) film, a liquid lens is prepared. By applying a DC voltage to the DE film, the liquid lens can be actuated. As a comparison, two liquid lenses, one in a millimeter scale and the other in a submillimeter scale, are demonstrated. In a relaxed state, the focal length of each liquid lens is the longest. In an actuated state, the diameter of each lens is reduced. As a result, their focal length is tuned. Here, the DE film functions as an actuator. Due to the biconvex shape and smooth liquid surface, each liquid lens can provide good optical performance. They also possess the merits of simple fabrication, compact structure, and easy operation. In contrast to the bigger liquid lens, the smaller one can present a better mechanical stability without the concern of the gravitational effect.

  20. Laser differential confocal lens thickness measurement

    International Nuclear Information System (INIS)

    Based on the property that the absolute zero of an axial intensity curve exactly corresponds to the focus of the objective in a differential confocal system (DCS), a new laser differential confocal lens thickness measurement is proposed to achieve the high-precision non-contact measurement of lens thickness. The proposed approach uses the absolute zero of DCS axial response curve to precisely identify the vertexes of the test lens, obtains the central optical thickness of the test lens, and then uses the radius of curvature and refractive index of the test lens and the ray tracing facet iterative calculation to obtain the central geometrical thickness of the test lens. The theoretical analyses and preliminary experiments indicate that the measurement accuracy is better than 0.03%. (paper)

  1. Eye model with controllable lens scattering

    OpenAIRE

    Paeglis, R; Ozolinsh, M; Cikmacs, P; Andersson-Engels, Stefan

    2001-01-01

    A model of human eye for experiments in vision research has been developed using PLZT ceramics. This ``artificial eye{''} allows to simulate light scattering caused by cataract in the eye lens. Light scattering of a composite eye lens of the model depends on the electric field applied to a transparent electrooptic PLZT ceramics plate that is attached directly to the lens. The image degradation in such a model eye at various degrees of scattering is studied observing and recording the ...

  2. The lens and source of the optical Einstein ring gravitational lens ER 0047-2808

    OpenAIRE

    Wayth, Randall B.; Warren, Stephen J.; Lewis, Geraint F.; Hewett, Paul C.

    2004-01-01

    (Abridged) We perform a detailed analysis of the optical gravitational lens ER 0047-2808 imaged with WFPC2 on the Hubble Space Telescope. Using software specifically designed for the analysis of resolved gravitational lens systems, we focus on how the image alone can constrain the mass distribution in the lens galaxy. We find the data are of sufficient quality to strongly constrain the lens model with no a priori assumptions about the source. Using a variety of mass models, we find statistica...

  3. Role of Aquaporin 0 in lens biomechanics

    International Nuclear Information System (INIS)

    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−/−), AQP0 KO (heterozygous KO: AQP0+/−; homozygous KO: AQP0−/−; 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+/− 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 together they help to confer

  4. Stretchable Binary Fresnel Lens for Focus Tuning.

    Science.gov (United States)

    Li, Xueming; Wei, Lei; Poelma, René H; Vollebregt, Sten; Wei, Jia; Urbach, Hendrik Paul; Sarro, Pasqualina M; Zhang, Guo Qi

    2016-01-01

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material combines the excellent optical absorption properties of the CNT with the transparency and stretchability of the PDMS. By stretching the elastomeric composite in radial direction, the lens focal length is tuned. Good focusing response is demonstrated and a large focus change (≥24%) was achieved by stretching lenses up to 11.4%. PMID:27139747

  5. A Magnification Lens for Interactive Volume Visualization

    Energy Technology Data Exchange (ETDEWEB)

    LaMar, E; Hamann, B; Joy, K I

    2001-07-19

    Volume visualization of large data sets suffers from the same problem that many other visualization modalities suffer from: either one can visualize the entire data set and lose small details or visualize a small region and lose the context. In this paper, they present a magnification lens technique for volume visualization. While the notion of a magnification-lens is not new, and other techniques attempt to simulate the physical properties of a magnifying lens, their contribution is in developing a magnification lens that is fast, can be implemented using a fairly small software overhead, and has a natural, intuitive appearance. The issue with magnification lens is the border, or transition, region. The lens center and exterior have a constant zoom factor, and are simple to render. It is the border region that blends between the external and interior magnification, and has a non-constant magnification. They use the perspective-correct textures capability, available in most current graphics systems, to produce a lens with a tessellated border region that approximates linear compression with respect to the radius of the magnification lens. They discuss how a cubic border can mitigate the discontinuities resulting from the use of a linear function, without significant performance loss. They discuss various issues concerning development of a three-dimensional magnification lens.

  6. Simultaneous phacoemulsification, lens implantation and endothelial keratoplasty: Triple procedure

    Directory of Open Access Journals (Sweden)

    Nikolić Ljubiša

    2011-01-01

    Full Text Available Introduction. Simultaneous Descemet stripping endothelial keratoplasty, phacoemulsification, and intraocular lens implantation are indicated in Fuchs’ dystrophy with associated cataract. Compared to the standard method of the triple procedure which includes penetrating keratoplasty, this new method has the advantages of sutureless surgery, small limbal incision, faster recovery, less surface problems, less astigmatism, stronger tensile strength and more predictable calculation of the intraocular lens power. This is the first report of such a combination of procedures in our literature. Case report. A 76-year-old woman suffered from a gradual bilateral visual loss. The best corrected visual acuity was 20/60 (right eye and finger counting at 1m (left eye. Corneal thickness was 590 μm and 603 μm, respectively. A marked cornea guttata and nuclear cataract were present in both eyes. Phacoemulsification, lens implantation, and Descemet stripping were done in the left eye. The posterior lamellar corneal graft, 8.0 mm in diameter and about 150 μm thick, was bent and inserted through the limbal incision. The air was injected into the anterior chamber to attach the graft to the recipient stroma. The cornea remained clear, and the transplant was attached during a two-year follow-up. Visual acuity was 20/40 after two months, and 20/25 after one year. Conclusion. The new technique proved itself as a good choice for the treatment of a mild Fuchs’ dystrophy associated with cataract.

  7. Distribution of salicylate in lens and intraocular fluids and its effect on cataract formation.

    Science.gov (United States)

    Cotlier, E; Sharma, Y R; Niven, T; Brescia, M

    1983-06-14

    Retrospective studies on cataract development in patients with rheumatoid arthritis or osteoarthritis revealed a retardant effect of aspirin on diabetic and non-diabetic cataracts. The effect of aspirin is dose-dependent. The correlation coefficient between years delay for various cataracts subcategories versus aspirin taken (in tablets per day X years of intake) was 0.69. The ocular pharmacokinetics of 14C acetylsalicylic acid or salicylate were determined after intravenous or intraperitoneal administration to rabbits. 14C acetylsalicylic acid penetrates rapidly into rabbit lens and aqueous humor after intravenous administration. After intraperitoneal administration, salicylate levels in rabbit plasma, similar to those of humans receiving four to six aspirin tablets (325 mg each), result in accumulation of salicylate by lens (mean +/- SD) of 405 +/- 72 mumoles/g and 620 +/- 30 mumoles/g at two and four hours, respectively. At those dosages, salicylate is cleared in 24 hours from rabbit plasma and intraocular fluids, but retained by lens. Penetration of salicylate into rabbit lens and rat lens is dose-dependent. The retardant aspirin effect in diabetic cataracts is linked to inhibition of tissue aldose reductase and lens protein glycosylation. Deceleration of galactose cataract formation in rats occurs after daily salicylate intraperitoneal injections of 100 mg/kg a day. PMID:6859071

  8. CO2 Efflux from Cleared Mangrove Peat

    OpenAIRE

    Lovelock, Catherine E.; Roger W Ruess; Feller, Ilka C.

    2011-01-01

    BACKGROUND: CO(2) emissions from cleared mangrove areas may be substantial, increasing the costs of continued losses of these ecosystems, particularly in mangroves that have highly organic soils. METHODOLOGY/PRINCIPAL FINDINGS: We measured CO(2) efflux from mangrove soils that had been cleared for up to 20 years on the islands of Twin Cays, Belize. We also disturbed these cleared peat soils to assess what disturbance of soils after clearing may have on CO(2) efflux. CO(2) efflux from soils de...

  9. Studies on the solubilization of the water-insoluble fraction from human lens and cataract.

    Science.gov (United States)

    Ortwerth, B J; Olesen, P R

    1992-12-01

    Studies were carried out comparing the ability of urea extraction and sonication to solubilize the water-insoluble (WI) protein fraction from human lens tissue. Sonication and urea extraction were able to solubilize greater than 80% of the insoluble protein whether whole lenses or lens nuclei were used. This was true for normal lens and +1 cataracts; however, only 60% solubilization was obtained with the WI fraction from more advanced cataracts. Equal aliquots of a WI fraction from both pooled normal and pooled cataract lens nuclei were solubilized with and without reducing agents. The addition of dithiothreitol (DTT) had no significant effect on solubilization of the normal lens WI fraction. DTT did increase the protein solubilized from the cataract WI fraction by 30% with urea extraction; however, no increase was seen with sonication. When sodium borohydride was used as the reducing agent, essentially the same results were obtained. The solubilized protein populations were identical by SDS-PAGE and amino acid analysis. The addition of reducing agents had no effect on the amino acid content of the solubilized proteins with the single exception of lysine. This amino acid was markedly decreased in the proteins extracted in the presence of 40 mM sodium borohydride, but not with DTT. These data suggest that the borohydride not only increased the amount of protein solubilized, but likely also stabilized glycated lysine residues during the acid hydrolysis. Therefore, sonication readily provides a soluble preparation of the WI proteins from normal and cataract lens nuclei without the need for denaturing agents, however, disulfide-linked and lysine modified crystallins were best solubilized with urea. PMID:1486936

  10. 糖尿病合并白内障人工晶状体植入术后眼内炎的临床及预后分析%The clinical and prognosis of endophthalmitis of diabetes complicated with cataract extraction and intraocular lens implantation after operation

    Institute of Scientific and Technical Information of China (English)

    柴建廷; 段笃文; 王秀芳

    2014-01-01

    目的:探讨糖尿病合并白内障人工晶状体植入术后眼内炎的临床及预后。方法对我院眼科2008年1月-2013年5月收治的糖尿病合并白内障人工晶状体植入术后眼内炎6例进行临床分析。结果6例均行细菌培养+药敏试验,给予局部+全身抗感染治疗,4例行玻璃体切割+球内注药。术后1周视力:1例0.5,1例0.2,2例0.1,2例数指/20 cm。结论糖尿病合并白内障术后眼内炎患者的视力预后不良,对此类患者必须注重围术期的预防。%Objective To investigate the clinical and prognosis of endophthalmitis of diabetes complicated with cataract extraction and intraocular lens implantation after operation. Methods 6 patients with endophthalmitis were analyzed. Results Bacterial culture and drug sensitive test were made in 6 cases,and giving local and systemic anti infection thraphy.4 cases were treated with vitrectomy and ball injection.visual acuity of a week after operation (1 case 0.5;1 case 0.2;2 cases 0.1;2 cases/20cm).Conclusion The prognosis of diabetes complicated with cataract were bad,prevention must were made in peri-operation for such patients.

  11. 27 CFR 9.99 - Clear Lake.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Clear Lake. 9.99 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.99 Clear Lake. (a) Name. The name of the viticultural area described in this section is “Clear Lake.” (b) Approved...

  12. Flat lens for seismic waves

    CERN Document Server

    Brule, Stephane; Guenneau, Sebastien

    2016-01-01

    A prerequisite for achieving seismic invisibility is to demonstrate the ability of civil engineers to control seismic waves with artificially structured soils. We carry out large-scale field tests with a structured soil made of a grid consisting of cylindrical and vertical holes in the ground and a low frequency artificial source (< 10 Hz). This allows the identification of a distribution of energy inside the grid, which can be interpreted as the consequence of an effective negative refraction index. Such a flat lens reminiscent of what Veselago and Pendry envisioned for light opens avenues in seismic metamaterials to counteract the most devastating components of seismic signals.

  13. Controversies in intraocular lens implantation in pediatric uveitis.

    Science.gov (United States)

    Phatak, Sumita; Lowder, Careen; Pavesio, Carlos

    2016-12-01

    Cataract is one of the most common and visually debilitating complications of pediatric uveitis. It develops as a consequence of chronic inflammation and steroid use and is seen most often in juvenile idiopathic arthritis (JIA)-associated uveitis. Cataract extraction with intraocular lens (IOL) insertion has been carried out with a measure of success in non-uveitic pediatric eyes, but in cases of uveitis, multiple factors affect the final outcome. Chronic inflammation and its sequelae such as band keratopathy, posterior synechiae, and cyclitic membranes make surgical intervention more challenging and outcome less certain. Postoperative complications like increased inflammation, glaucoma, posterior capsular opacification, retrolental membranes, and hypotony may compromise the visual outcome. Early refractive correction is imperative in pediatric eyes to prevent amblyopia. The use of contact lenses and intraocular lenses in pediatric uveitic eyes were fraught with complications in the past. Surgical interventions such as vitreo-lensectomy followed by contact lens fitting and small incision cataract surgery followed by different types of intraocular lenses have been utilized, and many reports have been published, albeit in small patient groups. This review analyzes and discusses the existing literature on intraocular lens implantation in cases of pediatric uveitic cataract surgery. PMID:27009616

  14. Shadow photogrammetric method for assessing changes in physical lens dimensions during immersion in tissue preservation media

    Science.gov (United States)

    Rosen, Alexander; Denham, David B.; Manns, Fabrice; Fernandez, Viviana; Stoiber, Joseph; Augusteyn, Robert; Parel, Jean-Marie A.

    2003-07-01

    Purpose: To develop a technique to assess isotonic solutions for crystalline lens preservation. Methods: BSS, Ringer"s, Dulbecco"s Modified Eagle Medium (DMEM), and TC 199 have been selected for experimentation. Donor human cadaver lenses are extracted by cutting the zonules and vitreous adherences. A custom-made testing cell and modified optical comparator are used for imaging, and the lens diameter and thickness profiles are measured using digital photography and a graphics program. Measurements are taken every 5 minutes for the 1st hour and then every 15 minutes for 4 hrs. The volume of the lens at each interval is approximated, assuming rotational symmetry, by using the equation for the volume of an ellipsoid. The changes in diameter, thickness, and volume versus time are analyzed to compare the effect of each solution. Results: The measurement resolution for the digital technique is 13μm. Lens thickness changed more significantly than diameter and volume. All four solutions produced similar preliminary results with maximum diameter, thickness, and volume changes of approximately -2%, +6%, and +3%, respectively. Conclusion: Shadowphotogrammetry can measure the lens physical dimensions to +/-13um and can be used to determine the effect of preservation media. This technique may be useful for assessing the physical effects of chemical and biological substances on the lens osmotic transport system.

  15. Protection of the eye lens

    International Nuclear Information System (INIS)

    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.)

  16. Terminal lens for an FN tandem

    International Nuclear Information System (INIS)

    An electrostatic quadrupole triplet (ELQT) will be installed in the terminal of the Argonne FN tandem accelerator. The lens will be used in conjunction with foil stripping to maximize the transmission of heavy ions through the high-energy accelerator tube. The lens has steering capability and is controlled by a microcomputer located in the terminal

  17. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    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)

  18. Contact lens sensors in ocular diagnostics.

    Science.gov (United States)

    Farandos, Nicholas M; Yetisen, Ali K; Monteiro, Michael J; Lowe, Christopher R; Yun, Seok Hyun

    2015-04-22

    Contact lenses as a minimally invasive platform for diagnostics and drug delivery have emerged in recent years. Contact lens sensors have been developed for analyzing the glucose composition of tears as a surrogate for blood glucose monitoring and for the diagnosis of glaucoma by measuring intraocular pressure. However, the eye offers a wider diagnostic potential as a sensing site and therefore contact lens sensors have the potential to improve the diagnosis and treatment of many diseases and conditions. With advances in polymer synthesis, electronics and micro/nanofabrication, contact lens sensors can be produced to quantify the concentrations of many biomolecules in ocular fluids. Non- or minimally invasive contact lens sensors can be used directly in a clinical or point-of-care setting to monitor a disease state continuously. This article reviews the state-of-the-art in contact lens sensor fabrication, their detection, wireless powering, and readout mechanisms, and integration with mobile devices and smartphones. High-volume manufacturing considerations of contact lenses are also covered and a case study of an intraocular pressure contact lens sensor is provided as an example of a successful product. This Review further analyzes the contact lens market and the FDA regulatory requirements for commercialization of contact lens sensors. PMID:25400274

  19. Sub-wavelength imaging with a left-handed material flat lens

    OpenAIRE

    Feise, Michael W.; Yuri S. Kivshar

    2004-01-01

    We study numerically, by means of the pseudospectral time-domain method, the unique features of imaging by a flat lens made of a left-handed metamaterial that possesses the property of negative refraction. We confirm the earlier finding that a left-handed flat lens can provide near-perfect imaging of a point source and a pair of point sources with clear evidence of the sub-wavelength resolution. We illustrate the limitation of the resolution in the time-integrated image due to the presence of...

  20. Optimization of Zoom Lens with Discrete State of Liquid Lens Elements by Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Cheng-Mu Tsai

    2015-01-01

    Full Text Available This paper is to employ liquid lens elements to design a lens with zoom function by using the genetic algorithm (GA optimization. The liquid lens elements used in the proposal can apply voltage adjustment to generate the electrical field that induces the liquid with electric conductivity to vary the surface curvature between two different kinds of liquids. According to the voltage level, the liquid lens element makes the discrete variation of the curvature and thickness realize the zoom function without moving the lens groups so that the overall length can be reduced. However, it is difficult to design the zoom lens under the discrete variation of the curvature and thickness in the liquid lens elements and the mechanical space that is constantly limited. The GA offers a flexible way for lens optimization. We regarded the spot size as the fitness function to look for the optimum curvatures, thickness, and the corresponding statuses of liquid lens elements for the zoom lens. As a result, the zoom lens with constant space can be realized by running the selection, crossover, and mutation operation in the GA optimization.

  1. All-dielectric subwavelength metasurface focusing lens.

    Science.gov (United States)

    West, Paul R; Stewart, James L; Kildishev, Alexander V; Shalaev, Vladimir M; Shkunov, Vladimir V; Strohkendl, Friedrich; Zakharenkov, Yuri A; Dodds, Robert K; Byren, Robert

    2014-10-20

    We have proposed, designed, manufactured and tested low loss dielectric micro-lenses for infrared (IR) radiation based on a dielectric metamaterial layer. This metamaterial layer was created by patterning a dielectric surface and etching to sub-micron depths. For a proof-of-concept lens demonstration, we have chosen a fine patterned array of nano-pillars with variable diameters. Gradient index (GRIN) properties were achieved by engineering the nano-pattern characteristics across the lens, so that the effective optical density of the dielectric metamaterial layer peaks around the lens center, and gradually drops at the lens periphery. A set of lens designs with reduced reflection and tailorable phase gradients have been developed and tested, demonstrating focal distances of a few hundred microns, beam area contraction ratio up to three, and insertion losses as low as 11%. PMID:25401653

  2. Method of a Cataract Tunnel Extraction at an Expressed Corticocapsular Adhesion

    OpenAIRE

    2010-01-01

    Aim of investigation is an increase of the cataract tunnel extraction effectiveness by elaboration of the lens nucleus extraction new method at an expressed corticocapsular adhesion. Materials and Methods. An extraction of the lens nucleus was made according to elaborated method, including a low diameter nucleus turning over to 180° with a subsequent extraction through a tunnel incision of a 6—8 mm fibrous capsule with a use of elaborated loop-cannula, in 50 patients with an age cataract,...

  3. Hyalinizing clear cell carcinoma: A rare entity

    OpenAIRE

    P Venkat Baghirath; J Vijay Kumar; B Hari Vinay

    2011-01-01

    Hyalinizing clear cell carcinoma (HCCC) is an uncommon malignant salivary gland tumor accounting for about 1% of all intra-oral salivary gland tumors. Microscopic diagnosis of clear cell carcinoma may be challenging because of the spectrum of features which frequently overlaps with the other salivary gland tumors that contain clear cells, and thus it may be a diagnosis of exclusion. Here we, report a case of HCCC in a 36 years old female with detailed histological, histochemical and immunohis...

  4. Clear cell carcinoma of the lung.

    OpenAIRE

    Edwards, C; Carlile, A

    1985-01-01

    Six tumours of the lung initially classified as clear cell carcinoma, were studied. Examination of further material by light and electron microscopy showed adenocarcinomatous differentiation in three cases and squamous differentiation in two. One case showed the features of a large cell anaplastic carcinoma. The clear appearance of the cytoplasm in paraffin sections was due to accumulations of glycogen that were partially removed during processing. It is concluded that clear cell carcinoma is...

  5. Primary clear cell sarcoma of bone

    International Nuclear Information System (INIS)

    Clear cell sarcoma is a rare soft tissue sarcoma of young adults with melanocytic differentiation. It occurs predominantly in the soft tissue of extremities, typically involving tendons and aponeuroses. Primary clear cell sarcoma of bone is extremely rare. We report a case of primary clear cell sarcoma of the right first metatarsal in a 48-year-old woman and provide a literature review of the entity. (orig.)

  6. Clearing over-the-counter derivatives

    OpenAIRE

    Ed Nosal

    2011-01-01

    Prior to the financial crisis of 2008, the over-the-counter derivatives market was not required to “clear” transactions. This changed with the signing of the new financial reform legislation, the Dodd–Frank Act on July 21, 2010. Going forward, most OTC derivatives will be cleared through a particular set of institutional arrangements: a regulated clearinghouse. This article provides an overview of how clearing works, the potential benefits of central clearing for OTC derivatives, and the opti...

  7. 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.

  8. Dendritic immune cell densities in the central cornea associated with soft contact lens types and lens care solution types: a pilot study

    Directory of Open Access Journals (Sweden)

    Sindt CW

    2012-03-01

    Full Text Available Christine W Sindt1, Trudy K Grout1, D Brice Critser1, Jami R Kern2, David L Meadows21University of Iowa Hospitals and Clinics, Iowa City, IA; 2Alcon Research Ltd, Fort Worth, TX, USABackground: The purpose of this study was to assess whether differences in central corneal dendritic immune cell densities associated with combinations of soft contact lenses and lens care solutions could be detected by in vivo confocal microscopy.Methods: Participants were adults naïve to contact lens wear (n = 10 or who wore soft contact lenses habitually on a daily-wear schedule (n = 38 or on a study-assigned schedule for 30 days with daily disposable silicone hydrogel lenses (n = 15. Central corneas were scanned using an in vivo confocal microscope. Cell densities were compared among groups by demographic parameters, lens materials, and lens care solutions (polyhexamethylene biguanide [PHMB], polyquaternium-1 and myristamidopropyl dimethylamine [PQ/MAPD], peroxide, or blister pack solution [for daily disposable lenses].Results: Among lens wearers, no associations were observed between immune cell densities and age, gender, or years of lens-wearing experience. Mean cell density was significantly lower (P < 0.01 in nonwearers (29 ± 23 cells/mm2, n = 10 than in lens wearers (64 ± 71 cells/mm2, n = 53. Mean cell density was lower (P = 0.21 with traditional polymer lenses (47 ± 44 cells/mm2, n = 12 than with silicone hydrogel lenses (69 ± 77 cells/mm2, n = 41. Lowest to highest mean density of immune cells among lens wearers was as follows: PQ/MAPD solution (49 ± 28 cells/mm2, blister pack solution (63 ± 81 cells/mm2, PHMB solution (66 ± 44 cells/mm2, and peroxide solution (85 ± 112 cells/mm2.Conclusion: In this pilot study, in vivo confocal microscopy was useful for detecting an elevated immune response associated with soft contact lenses, and for identifying lens-related and solution-related immune responses that merit further research.Keywords: Clear Care

  9. Explosive plane-wave lens

    Science.gov (United States)

    Marsh, Stanley P.

    1988-01-01

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive.

  10. 17 CFR 39.4 - Procedures for implementing derivatives clearing organization rules and clearing new products.

    Science.gov (United States)

    2010-04-01

    ... product until its registration as a derivatives clearing organization is reinstated under the procedures... clearing a new product that is not traded on a designated contract market or a registered derivatives... of the product that make it acceptable for clearing with a certification that the clearing of...

  11. 76 FR 45724 - Clearing Member Risk Management

    Science.gov (United States)

    2011-08-01

    ... techniques or other forms of information technology. Comments may be submitted directly to the Office of... COMMISSION 17 CFR Parts 1 and 23 RIN 3038-AD51 Clearing Member Risk Management AGENCY: Commodity Futures... extensive regulations addressing open access and risk management at the derivatives clearing...

  12. Internalization, Clearing and Settlement, and Liquidity

    NARCIS (Netherlands)

    Degryse, H.A.; van Achter, M.; Wuyts, G.

    2012-01-01

    Abstract: We study the relation between liquidity in financial markets and post-trading fees (i.e. clearing and settlement fees). The clearing and settlement agent (CSD) faces different marginal costs for different types of transactions. Costs are lower for an internalized transaction, i.e. when buy

  13. Acoustics of Clear Speech: Effect of Instruction

    Science.gov (United States)

    Lam, Jennifer; Tjaden, Kris; Wilding, Greg

    2012-01-01

    Purpose: This study investigated how different instructions for eliciting clear speech affected selected acoustic measures of speech. Method: Twelve speakers were audio-recorded reading 18 different sentences from the Assessment of Intelligibility of Dysarthric Speech (Yorkston & Beukelman, 1984). Sentences were produced in habitual, clear,…

  14. Keep Your Kidneys Clear: Kicking Kidney Stones

    Science.gov (United States)

    ... Your Kidneys Clear Keep Your Kidneys Clear Kicking Kidney Stones Some say that passing a kidney stone is like delivering a baby made of razor ... is that, although they can be excruciatingly painful, kidney stones rarely cause permanent damage, and you may be ...

  15. SNOW CLEARING SERVICE WINTER 2001-2002

    CERN Multimedia

    ST-HM Group; Tel. 72202

    2001-01-01

    As usual at this time of the year, the snowing clearing service, which comes under the control of the Transport Group (ST-HM), is preparing for the start of snow-clearing operations (timetable, stand-by service, personnel responsible for driving vehicles and machines, preparation of useful and necessary equipment, work instructions, etc.) in collaboration with the Cleaning Service (ST-TFM) and the Fire Brigade (TIS-FB). The main difficulty for the snow-clearing service is the car parks, which cannot be properly cleared because of the presence of CERN and private vehicles parked there overnight in different parts of the parking areas. The ST-HM Transport Group would therefore like to invite you to park vehicles together in order to facilitate the access of the snow ploughs, thus allowing the car parks to be cleared more efficiently before the personnel arrives for work in the mornings.

  16. Cataract phacoemulsification with intraocular lens implantation after keratoprosthetics by Burn Vascular Leukoma (A case report

    Directory of Open Access Journals (Sweden)

    E.V. Kovshun,

    2014-01-01

    Full Text Available ABSTRACT Purpose. To evaluate the phacoemulsification (Phaco with intraocular lens (IOL implantation outcome after keratoprosthetics in patient with burn vascular leukoma. Material and methods. A patient, 39 years old, with a thinned burn vascular leukoma as a result of burns, limbal stem cell deficiency of both eyes, local simblefaron in the left eye (OS, secondary glaucoma (OS, after a simblefaron dissection and a glaucoma operation (OS, it was performed keratoprosthetics with a undismountable model of keratoprosthesis with an improvement in visual acuity (VA from 1/∞ рr. сerta up to 0.5 u/c. But there was a decrease in the VA to 0.01 u/c in 13 months. The aglia with vascularization and total overgrowth on the conjunctiva were observed on admission. Haptic keratoprostheses elements were not visible. Optical cylinder was clear. Anterior chamber depth was less than the average. A pronounced opacity of cortical layers of crystalline lens were defined. Fundus details were not visualized. A disturbance of topographic anatomical correlations in all structures of the anterior segment of the eye (ASE was revealed by the ultrasound bio-microscopy: corneal thickness — 1.47mm, anterior chamber depth in the central parts — 1.09mm, а lot of irido-corneal adhesions in the anterior chamber angle (ACA with anterior chamber closing by basal area of the iris, medium hypertrophy of the iris (0.43mm. The maximum size of the ciliary body was 0.74mm. Ciliary zonule fibers were heterogeneous: in three segments they were thickened, hypertrophied and with adhesions between them, in one segment lysed or fused with the iris. Posterior chamber dimensions were acutely asymmetrical. Anterior posterior size of lens w as 5.23mm. Despite the significant impairments of spatial relations in ASE structures in the patient the microinvasive Phaco with soft IOL implantation were carried out with the preventive purpose of possible complications during the highly traumatic

  17. Clear Cell Carcinoma and Clear Cell Odontogenic Carcinoma: a Comparative Clinicopathologic and Immunohistochemical Study

    OpenAIRE

    Bilodeau, Elizabeth A.; Hoschar, Aaron P.; Barnes, E. Leon; Hunt, Jennifer L.; Seethala, Raja R.

    2011-01-01

    Clear cell carcinoma or hyalinizing clear cell carcinoma (CCC) and clear cell odontogenic carcinoma (CCOC) are rare, low-grade and typically indolent malignancies that can be diagnostically challenging. In this study the clinicopathologic, histologic, and immunohistochemical features of 17 CCCs and 12 CCOCs are examined. The differential diagnosis of clear cell malignancies in the head and neck is discussed. The relationship of CCCs and CCOCs to other clear cell tumors on the basis of their i...

  18. Conjugate metamaterials and the perfect lens

    CERN Document Server

    Xu, Yadong; Xu, Lin; Chen, Huanyang

    2015-01-01

    In this letter, we show how transformation optics makes it possible to design what we call conjugate metamaterials. We show that these materials can also serve as substrates for making a subwavelength-resolution lens. The so-called "perfect lens", which is a lens that could focus all components of light (including propagating and evanescent waves), can be regarded as a limiting case, in which the respective conjugate metamaterials approach the characteristics of left-handed metamaterials, which have a negative refractive index.

  19. Accelerating convergence in automatic lens design

    International Nuclear Information System (INIS)

    Among the various factors that slow lens optimization-insufficient performance targets, the absence of a unique solution, false local minima, a poorly scaled change vector, failure to find the optimum damping number, and failure to equalize the parameter gradients-the importance of parameter gradient equalization has been insufficiently recognized. Gradients can be approximately equalized by scaling the lens to a suitable size while it is being optimized. For best results, the size of the damping number should also be optimized during each iteration. If these two procedures are followed, scaling the change vector is usually not crucial. To illustrate the importance of parameter equalization, a lens optimization is analyzed

  20. Fresnel lens solar beam convergence properties

    Science.gov (United States)

    Huang, Minshuang; Tian, Feng

    2014-11-01

    Use the law of refraction of light for theoretical analysis of sunlight incident Fresnel lens, summary of the relationship between Fresnel lens solar light beam convergence characteristics and beam incident angle,beam incident position.Through the analysis of the calculation and experimental, to obtain a variety of incident angle lens center and best gathering focal spot the size of the data.Discuss the incident angle, incident location,the relationship between convergence center and focal spot size.For the sun acquisition system of the light from the sun and optical fiber coupling design do sufficient theory design basis.

  1. Design and Construction of Solenoid Magnetic Lens for Focusing Electron Beam from Thermionic Electron Gun

    International Nuclear Information System (INIS)

    Electron gun is an important part of an electron accelerator for producing electron beam to be irradiated on material. The electron gun of electron accelerator constructed at P3TM BATAN, is a thermionic electron gun, A solenoid magnetic lens had been designed and constructed for focusing electron beam extracted from the electron gun in such away that all of the electron beam enter the accelerating tube. Technical specification of the solenoid magnetic lens is given in this paper. Measurement of magnetic field generated by solenoid coil shows that the largest magnetic field is in the middle of the solenoid coil. The test using the thermionic electron gun shows the focusing effect on electron beam by the solenoid magnetic lens. The focus strength is maximum after the coil current reaches 9 A. (author)

  2. 21 CFR 886.1390 - Flexible diagnostic Fresnel lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Flexible diagnostic Fresnel lens. 886.1390 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1390 Flexible diagnostic Fresnel lens. (a) Identification. A flexible diagnostic Fresnel lens is a device that is a very thin lens which...

  3. 16 CFR 315.6 - Expiration of contact lens prescriptions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Expiration of contact lens prescriptions... CONGRESS CONTACT LENS RULE § 315.6 Expiration of contact lens prescriptions. (a) In general. A contact lens... Commission, its employees, and its representatives. (3) No prescriber shall include an expiration date on...

  4. Current practice of cataract extraction and anaesthesia.

    OpenAIRE

    Hodgkins, P R; Luff, A J; Morrell, A. J.; Botchway, L. T.; Featherston, T. J.; Fielder, A R

    1992-01-01

    A questionnaire regarding preferred methods of cataract extraction and anaesthesia was sent to 456 consultant ophthalmologists in England and Wales. Replies were received from 86% (n = 392), 83% (n = 380) having completed the questionnaire in full. The most frequently employed surgical approach was non-automated extracapsular cataract extraction. Only 2% of surgeons (n = 8) used phacoemulsification routinely and 2% (n = 7) used intracapsular extraction. Intraocular lens implantation was the s...

  5. Luneburg and flat lens based on graded photonic crystal

    Science.gov (United States)

    Liu, Wei; Sun, Xiaohong; Gao, Minglei; Wang, Shuai

    2016-04-01

    Square-lattice graded photonic crystals employed for designing Luneburg and Flat Lens is presented. Comparable simulation of the Luneburg lens with TE and TM polarizations predicts that TM lens possesses of enlarged transmission bandwidth and strengthened focusing ability, in comparison with TE lens. As a typical simplified counterpart, the evolution of focusing intensity and numerical aperture of the flat lens is achieved. What is more, those Luneburg and Flat Lens can withstand imperfect gradients in structure design. This will provide a guidance to produce a high quality focusing lens with small size, short focal length and large numerical aperture applied in the integrated photonic devices.

  6. Bionic intraocular lens with variable focus and integrated structure

    Science.gov (United States)

    Liang, Dan; Wang, Xuan-Yin; Du, Jia-Wei; Xiang, Ke

    2015-10-01

    This paper proposes a bionic accommodating intraocular lens (IOL) for ophthalmic surgery. The designed lens has a solid-liquid mixed integrated structure, which mainly consists of a support ring, elastic membrane, rigid lens, and optical liquid. The lens focus can be adjusted through the deformation of the lens front surface when compressed. The integrated structure of the IOL is presented, as well as a detailed description of the lens materials and fabrication process. Images under different radial pressures are captured, and the lens deformation process, accommodating range, density, and optical property are analyzed. The designed lens achieves a 14.6 D accommodating range under a radial pressure of 51.4 mN and a 0.24 mm alteration of the lens outer radius. The deformation property of the lens matches well with the characteristic of the eye and shows the potential to help patients fully recover their vision accommodation ability after the cataract surgery.

  7. RISK FACTORS FOR CONTACT LENS INDUCED PAPILLARY CONJUNCTIVITIS ASSOCIATED WITH SILICONE HYDROGEL CONTACT LENS WEAR

    Science.gov (United States)

    Tagliaferri, Angela; Love, Thomas E.; Szczotka-Flynn, Loretta

    2014-01-01

    BACKGROUND Contact lens induced papillary conjunctivitis (CLPC) continues to be a major cause of dropout during contact lens extended wear. This retrospective study explores risk factors for the development of CLPC during silicone hydrogel lens extended wear. METHODS Data from 205 subjects enrolled in the Longitudinal Analysis of Silicone Hydrogel Contact Lens (LASH) study wearing lotrafilcon A silicone hydrogel lenses for up to 30 days of continuous wear were used to determine risk factors for CLPC in this secondary analysis of the main cohort. The main covariates of interest included substantial lens-associated bacterial bioburden, and topographically determined lens base curve-to-cornea fitting relationships. Additional covariates of interest included history of prior adverse events, time of year, race, education level, gender and other subject demographics. Statistical analyses included univariate logistic regression to assess the impact of potential risk factors on the binary CLPC outcome, and Cox proportional hazards regression to describe the impact of those factors on time-to-CLPC diagnosis. RESULTS Across 12 months of follow-up, 52 subjects (25%) experienced CLPC. No associations were found between CLPC development and the presence of bacterial bioburden, lens-to-cornea fitting relationships, history of prior adverse events, gender or race. CLPC development followed the same seasonal trends as the local peaks in environmental allergans. CONCLUSIONS Lens fit and biodeposits, in the form of lens associated bacterial bioburden, were not associated with the development of CLPC during extended wear with lotrafilcon A silicone hydrogel lenses. PMID:24681609

  8. Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher

    Science.gov (United States)

    Marussich, Lauren; Manns, Fabrice; Nankivil, Derek; Maceo Heilman, Bianca; Yao, Yue; Arrieta-Quintero, Esdras; Ho, Arthur; Augusteyn, Robert; Parel, Jean-Marie

    2015-01-01

    Purpose To determine if the lens volume changes during accommodation. Methods The study used data acquired on 36 cynomolgus monkey lenses that were stretched in a stepwise fashion to simulate disaccommodation. At each step, stretching force and dioptric power were measured and a cross-sectional image of the lens was acquired using an optical coherence tomography system. Images were corrected for refractive distortions and lens volume was calculated assuming rotational symmetry. The average change in lens volume was calculated and the relation between volume change and power change, and between volume change and stretching force, were quantified. Linear regressions of volume-power and volume-force plots were calculated. Results The mean (±SD) volume in the unstretched (accommodated) state was 97 ± 8 mm3. On average, there was a small but statistically significant (P = 0.002) increase in measured lens volume with stretching. The mean change in lens volume was +0.8 ± 1.3 mm3. The mean volume-power and volume-load slopes were −0.018 ± 0.058 mm3/D and +0.16 ± 0.40 mm3/g. Conclusions Lens volume remains effectively constant during accommodation, with changes that are less than 1% on average. This result supports a hypothesis that the change in lens shape with accommodation is accompanied by a redistribution of tissue within the capsular bag without significant compression of the lens contents or fluid exchange through the capsule. PMID:26161985

  9. Minus Piggyback Lens Overlaying ReSTOR® Multifocal Lens in High Myopia

    OpenAIRE

    Gupta, Isha; Oakey, Zack; Stagg, Brian C; Ambati, Balamurali K.

    2013-01-01

    Background We report the case of a 40-year-old female patient treated with implantation of the Acrysof® IQ ReSTOR® lens (Alcon, Fort Worth, Tex., USA) with overlaying Acrysof EXpand® minus piggyback lens (Alcon). Methods The patient had high myopia and was diagnosed with presbyopia and bilateral posterior subcapsular cataract. She desired to be spectacle-free and opted to undergo bilateral placement of the ReSTOR multifocal lens. The necessary intraocular lens (IOL) power was +3.5 in the righ...

  10. Specific eye-head coordination enhances vision in progressive lens wearers.

    Science.gov (United States)

    Rifai, Katharina; Wahl, Siegfried

    2016-09-01

    In uncorrected vision all combinations of eye and head positions are visually equivalent; thus, there is no need for a specific modification of eye-head coordination in young healthy observers. In contrast, the quality of visual input indeed strongly depends on eye position in the majority of healthy elderly drivers, namely in progressive additional lens (PALs) wearers. For a given distance, only specific combinations of eye and head position provide clear vision in a progressive lens wearer. However, although head movements are an integral part of gaze behavior, it is not known if eye-head coordination takes part in the enhancement of visual input in healthy individuals. In the current study we determined changes in eye-head coordination in progressive lens wearers in challenging tasks with high cognitive load, in the situation of driving. During a real-world drive on an urban round track in Stuttgart, gaze movements and head movements were measured in 17 PAL wearers and eye-head coordination was compared to 27 controls with unrestricted vision. Head movement behavior, specific to progressive lens wearers, was determined in head gain and temporal properties of head movements. Furthermore, vertical eye-head coordination was consistent only among PAL wearers. The observed differences in eye-head coordination clearly demonstrate a contribution of head movements in the enhancement of visual input in the healthy human visual system. PMID:27604068

  11. 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

  12. Characteristics of soft X-ray lens

    International Nuclear Information System (INIS)

    A soft X-lens was devised with waveguide X-ray optics of total external reflection (TER). The lens consists of a stack of 1 387 TER waveguides with inner diameter of 0.45 mm and outer diameter of 0.60 mm. With the help of plasma sources of soft X-ray radiation, high density of pure soft X-ray radiation (without plasma expansion fragments) with broad-band spectral range can be obtained at the focus of the lens. As laser-plasma is considered, the radiation density of 1.3 x 105 W/cm2 is obtained, the transmission coefficient is 18.6%, the ratio of the density at the focus with and without the lens is 1000 and the radiation capture is 28.9 degree. The density of 0.5 TW/cm2 can be obtained as far as Qiang-Guang I facility is considered. (authors)

  13. Adaptive lens using liquid crystal concentration redistribution

    Science.gov (United States)

    Ren, Hongwen; Lin, Yi-Hsin; Wu, Shin-Tson

    2006-05-01

    An adaptive lens using electrically induced liquid crystal (LC)/monomer concentration redistribution is demonstrated. In the absence of an electric field, the LC/monomer mixture is homogeneously distributed. Application of an inhomogeneous electric field causes the LC molecules to diffuse towards the high field region and the liquid monomer towards the low field region. On the other hand, the LC molecules tend to diffuse from high to low concentration direction in order to balance the concentration change. A gradient LC concentration is thus obtained. Using the gradient LC concentration, we demonstrate a tunable-focus lens. Compared with a conventional LC lens, our lens has advantages in small astigmatism and without light scattering, but its response time is slower.

  14. Methane Detector With Plastic Fresnel Lens

    Science.gov (United States)

    Grant, W. B.

    1986-01-01

    Laser detector for natural gas leaks modified by substitution of molded plastic lens for spherical mirror. By measuring relative attenuation at two wavelengths, detector used to check for methane escaping from pipelines above or below ground and from landfill.

  15. High Altitude Clear Air Turbulence Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Air Force Flight Dynamics Laboratory conducted the High Altitude Clear Air Turbulence Project in the mid 1960s with the intention of better understanding air...

  16. Primary clear cell carcinoma of the larynx.

    OpenAIRE

    G.Pesavento; Ferlito, A; Recher, G.

    1980-01-01

    The clinical and pathological findings in three patients with clear cell carcinoma of the larynx are described. This type of neoplasm in the larynx is extremely rare. The aggressiveness of the tumour and its high biological malignancy are stressed.

  17. Clear corneal incision in cataract surgery

    Directory of Open Access Journals (Sweden)

    Ammar M Al Mahmood

    2014-01-01

    Full Text Available Since the introduction of sutureless clear corneal cataract incisions, the procedure has gained increasing popularity worldwide because it offers several advantages over the traditional sutured scleral tunnels and limbal incisions. Some of these benefits include lack of conjunctival trauma, less discomfort and bleeding, absence of suture-induced astigmatism, and faster visual rehabilitation. However, an increasing incidence of postoperative endophthalmitis after clear corneal cataract surgery has been reported. Different authors have shown a significant increase up to 15-fold in the incidence of endophthalmitis following clear corneal incision compared to scleral tunnels. The aim of this report is to review the advantages and disadvantages of clear corneal incisions in cataract surgery, emphasizing on wound construction recommendations based on published literature.

  18. Ion clearing the the XLS-ring

    Energy Technology Data Exchange (ETDEWEB)

    Bozoki, E.S.; Halama, H.

    1990-01-01

    The mechanism of ion capture by the beam, their effects on the beam as well as ways to clear the ions are discussed. Special attention is given to these questions for the SXLS ring. 20 refs., 5 figs., 4 tabs.

  19. Ion clearing the the XLS-ring

    International Nuclear Information System (INIS)

    The mechanism of ion capture by the beam, their effects on the beam as well as ways to clear the ions are discussed. Special attention is given to these questions for the SXLS ring. 20 refs., 5 figs., 4 tabs

  20. 23-gauge pars plana vitrectomy for management of posteriorly dislocated crystalline lens

    Directory of Open Access Journals (Sweden)

    Cho M

    2011-12-01

    Full Text Available Minhee Cho, RV Paul ChanWeill Cornell Medical College, Department of Ophthalmology, New York, NY, USAPurpose: Management of posteriorly dislocated crystalline lens has traditionally been performed with a standard 20-gauge vitrectomy system. This study demonstrates the use of a 23-gauge vitrectomy system for removal of retained lens fragments secondary to spontaneous dislocation or complicated cataract extraction.Methods: A retrospective, noncomparative, interventional consecutive case series at a single university medical center.Results: Fourteen eyes of 14 patients underwent a 23-gauge vitrectomy for removal of retained lens. Mean age was 75 years. Mean logMAR (logarithm of minimum angle of resolution visual acuity was 1.47 (Snellen equivalent 20/600 preoperatively and 0.37 (Snellen equivalent 20/50 postoperatively. A 20-gauge fragmatome was used in 64% of cases. The mean time to the best post-vitrectomy acuity was 4.9 weeks. The mean healing time was 25 days (6–48 days. Post-vitrectomy complications included choroidal detachment (two patients, vitreous hemorrhage (two patients, and acute ocular hypertension (two patients. The mean length of follow-up was 6.2 months (1–13 months.Conclusion: A 23-gauge vitrectomy system alone or in combination with the 20-gauge fragmatome is a safe and efficacious option for removal of dense posteriorly dislocated crystalline lens material.Keywords: lensectomy, retained lens, PPV

  1. A case of Alagille syndrome complicated by intraocular lens subluxation and rhegmatogenous retinal detachment

    Directory of Open Access Journals (Sweden)

    Fukumoto M

    2013-07-01

    Full Text Available Masanori Fukumoto, Tsunehiko Ikeda, Tetsuya Sugiyama, Mari Ueki, Takaki Sato, Eisuke Ishizaki Department of Ophthalmology, Osaka Medical College, Takatsuki City, Japan Abstract: This case report describes a case of Alagille syndrome with developing intraocular lens subluxation and rhegmatogenous retinal detachment 4 years after cataract surgery. A 15-year-old female patient with Alagille syndrome-associated cataracts in both eyes underwent phacoemulsification aspiration and intraocular lens implantation. Four years postoperative, intraocular lens subluxation developed in her left eye. For treatment, extraction of the dislocated intraocular lens, anterior vitrectomy, and intraocular lens fixation was performed. Three weeks later, the patient developed rhegmatogenous retinal detachment, which was well-treated by pars plana vitrectomy. Cataract surgery needs to be performed carefully in patients with Alagille syndrome due to the weakness of the zonule of Zinn. Careful postoperative observation is necessary for patients with Alagille syndrome who have undergone intraocular surgery in order to facilitate early detection of a possible rhegmatogenous retinal detachment. Keywords: Alagille syndrome, cataract, retina, surgery

  2. Role of Aquaporin 0 in lens biomechanics.

    Science.gov (United States)

    Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

    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(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); 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(+/-) 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 together they help to confer

  3. komunikace značky Clean & Clear

    OpenAIRE

    Nováková, Kateřina

    2009-01-01

    The objective of this thesis is to describe a communication campaign of Clean & Clear brand. A brand owned by Johnson & Johnson company specializing in cosmetics for teenage girls. Campaign is described into details, evaluated in terms of effectiveness of its communication tools by achieving marketing goals over a specified period of time. This thesis should confirm the suitability and effectivity of the communication mix applied for Clean & Clear brand in a specific enviroment of anti-acne c...

  4. Governance of securities clearing and settlement systems

    OpenAIRE

    Daniela Russo; Terry L. Hart; Chryssa Papathanassiou

    2004-01-01

    In the context of securities clearing and settlement systems, the nature of governance arrangements acquires a dimension that goes beyond their traditional function in corporate law. They constitute a tool for regulators and central banks to achieve their respective policy goals relating to market operation, market integrity, and systemic stability. In the light of the analysis of this paper, and pending a further evolution in the regulation of securities clearing and settlement in the Commun...

  5. Autophagy and mitophagy participate in ocular lens organelle degradation

    OpenAIRE

    Costello, M Joseph; Brennan, Lisa A.; Basu, Subharsee; Chauss, Daniel; Mohamed, Ashik; Gilliland, Kurt O.; Johnsen, Sönke; Menko, Sue; Kantorow, Marc

    2013-01-01

    The eye lens consists of a layer of epithelial cells that overlay a series of differentiating fiber cells that upon maturation lose their mitochondria, nuclei and other organelles. Lens transparency relies on the metabolic function of mitochondria contained in the lens epithelial cells and in the immature fiber cells and the programmed degradation of mitochondria and other organelles occurring upon lens fiber cell maturation. Loss of lens mitochondrial function in the epithelium or failure to...

  6. A Spectrometer Based on Diffractive Lens

    Institute of Scientific and Technical Information of China (English)

    WANG Daoyi; YAN Yingbai; JIN Guofan; WU Minxian

    2001-01-01

    A novel spectrometer is designed based on diffractive lens. It is essentially a flat field spectrometer. All the focal points are along the optical axis. Besides, all the asymmetrical aberrations vanish in our mounting. Thus low aberration can be obtained. In this article a diffractive lens is modeled as a special grating and analyzed by using a grating-based method. And a stigmatic point is introduced to reduce the aberrations.

  7. Veselago lens by photonic hyper-crystals

    CERN Document Server

    Huang, Zun

    2014-01-01

    An imaging system functioning as a Veselago lens has been proposed based on the novel concept of photonic "hyper-crystal" -- an artificial optical medium synthesizing the properties of hyperbolic materials and photonic crystals. This Veselago lens shows a nearly constant negative refractive index and substantially reduced image aberrations. It can find potential applications in photolithography and hot-spots detection of silicon-based integrated circuits.

  8. In vivo human crystalline lens topography

    OpenAIRE

    Sergio Ortiz; Pablo P\\xe9rez-Merino; Enrique Gambra; Alberto de Castro; Susana de Marcos

    2012-01-01

    Custom high-resolution high-speed anterior segment spectral domain optical coherence tomography (OCT) was used to characterize three-dimensionally (3-D) the human crystalline lens in vivo. The system was provided with custom algorithms for denoising and segmentation of the images, as well as for fan (scanning) and optical (refraction) distortion correction, to provide fully quantitative images of the anterior and posterior crystalline lens surfaces. The method was tested on an artificial eye ...

  9. Evolution and the Calcite Eye Lens

    CERN Document Server

    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.

  10. Multipurpose soft contact lens care in Japan

    OpenAIRE

    Toshida H; Kadota Y; Suto C; Ohta T; Murakami A

    2012-01-01

    Hiroshi Toshida1,2, Yoshiaki Kadota3, Chikako Suto2, Toshihiko Ohta1, Akira Murakami21Juntendo University Shizuoka Hospital, Department of Ophthalmology, Shizuoka, 2Juntendo University School of Medicine, Department of Ophthalmology, Tokyo, 3Bausch & Lomb Japan Co, Ltd, Research and Development, Tokyo, JapanPurpose: To assess the use of multipurpose lens care products via an online survey conducted among soft contact lens (SCL) wearers in Japan.Methods: The subjects were 1000 men and ...

  11. Skin optical clearing potential of disaccharides.

    Science.gov (United States)

    Feng, Wei; Shi, Rui; Ma, Ning; Tuchina, Daria K; Tuchin, Valery V; Zhu, Dan

    2016-08-01

    Skin optical clearing can significantly enhance the ability of biomedical optical imaging. Some alcohols and sugars have been selected to be optical clearing agents (OCAs). In this work, we paid attention to the optical clearing potential of disaccharides. Sucrose and maltose were chosen as typical disaccharides to compare with fructose, an excellent monosaccharide-OCA, by using molecular dynamics simulation and an ex vivo experiment. The experimental results indicated that the optical clearing efficacy of skin increases linearly with the concentration for each OCA. Both the theoretical predication and experimental results revealed that the two disaccharides exerted a better optical clearing potential than fructose at the same concentration, and sucrose is optimal. Since maltose has an extremely low saturation concentration, the other two OCAs with saturation concentrations were treated topically on rat skin in vivo, and optical coherence tomography imaging was applied to monitor the optical clearing process. The results demonstrated that sucrose could cause a more significant increase in imaging depth and signal intensity than fructose. PMID:27108771

  12. CO2 efflux from cleared mangrove peat.

    Directory of Open Access Journals (Sweden)

    Catherine E Lovelock

    Full Text Available BACKGROUND: CO(2 emissions from cleared mangrove areas may be substantial, increasing the costs of continued losses of these ecosystems, particularly in mangroves that have highly organic soils. METHODOLOGY/PRINCIPAL FINDINGS: We measured CO(2 efflux from mangrove soils that had been cleared for up to 20 years on the islands of Twin Cays, Belize. We also disturbed these cleared peat soils to assess what disturbance of soils after clearing may have on CO(2 efflux. CO(2 efflux from soils declines from time of clearing from ∼10,600 tonnes km(-2 year(-1 in the first year to 3000 tonnes km(2 year(-1 after 20 years since clearing. Disturbing peat leads to short term increases in CO(2 efflux (27 umol m(-2 s(-1, but this had returned to baseline levels within 2 days. CONCLUSIONS/SIGNIFICANCE: Deforesting mangroves that grow on peat soils results in CO(2 emissions that are comparable to rates estimated for peat collapse in other tropical ecosystems. Preventing deforestation presents an opportunity for countries to benefit from carbon payments for preservation of threatened carbon stocks.

  13. A comparison of anterior and posterior chamber lenses after cataract extraction in rural Africa: a within patient randomised trial

    OpenAIRE

    Waddell, K M; Reeves, B C; Johnson, G J

    2004-01-01

    Background: Extracapsular cataract extraction (ECCE) with a posterior chamber intraocular lens (PC IOL) is the preferred method of cataract surgery in developed countries. However, intracapsular cataract extraction (ICCE) with an anterior chamber lens (AC IOL) may be appropriate in rural Africa. A randomised controlled trial was carried out to compare these surgical strategies.

  14. Fresnel Lens Sidewall Design for Imaging Optics

    Science.gov (United States)

    Fujii, T.; Goulet, A.; Hattori, K.; Konno, K.; Tanaka, A.; Bosmans, R.; Sawada, M.; Yazawa, H.

    2015-03-01

    We developed a ray tracing simulation tool for imaging systems including a Fresnel lens with a quasi-arbitrary sidewall structure. One issue with Fresnel lens is that noise in the image plane can appear from rays passing through or reflected at its sidewalls. One way to reduce it is to modify the orientation of the sidewalls so that rays will not reach the image plane. To find the best sidewall orientations, we developed a method where locally, a sidewall can freely be oriented. We could then derive the best modulation scheme for each Fresnel lens sidewall. In the case of a single imaging Fresnel lens, relative parasite noise intensity could mostly be prevented. To experimentally check our method, snapshot images were taken with single Fresnel lenses and a single spherical lens. No noticeable differences in image quality could be observed using a standard C-MOS camera. However, parasite noise could experimentally be detected with a Fresnel lens prototype when using a very! high-dynamic range C-MOS camera.

  15. Acoustic lens for capacitive micromachined ultrasonic transducers

    International Nuclear Information System (INIS)

    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)

  16. Decentration of a spectacle lens

    Science.gov (United States)

    Bartkowska, Janina

    1998-10-01

    The correct placing of the lenses plays an important role in the ophthalmological practice. Centering errors cause disadvantageous prismatic effects and worsen image quality. The optical axes of the spectacles should pass by rotation centers of the eyes. An often met error consists in a faulty center distance, in a wrong positioning of the lenses axis or their placing too high, too low, or in the inclining without lowering. The errors reach some millimeters and some degrees of arc. In technical optics acceptable errors are fractions or hundredths of millimeters and minutes or seconds of arc. Therefore only first powers of decentration are taken into account. In the spectacle optics one cannot omit the second powers of decentration vector. An astigmatism proportional to the square of decentration arises in the center of the field. The off axis aberrations are a quadratic function of the decentration with linear term. The aberrations are calculated by admitting a virtual diaphragm in the point of intersection of the lens axis with the eye's view axis. This method can be applied also to the lenses with aspheric surface and to astigmatic lenses, if the decentration vector lies in one of the principal sections of toroidal surface.

  17. MAGNITUDE OF POST OPERATIVE CORNEAL ASTIGMATISM AFTER PHACOEMULSIFICATION THROUGH 3.2MM TEMPORAL CLEAR CORNEAL INCISION

    Directory of Open Access Journals (Sweden)

    Neeraj

    2014-04-01

    Full Text Available Surgically induced astigmatism (SIA is a common obstacle for achieving excellent uncorrected visual acuity after Phacoemulsification with implantation of foldable IOL. The aim of the study was to determine the magnitude of surgically induced post-operative astigmatism after phacoemulsification with intraocular lens implantation through a temporal clear corneal incision. This study included 16 eyes with senile cataract which were operated using phacoemulsification with implantation of a foldable intraocular lens through a temporal clear corneal incision. Temporal incision at 180 degree was used for all cases. Astigmatism was measured by autorefracto keratometer preoperatively and at 6 weeks postoperatively. The mean surgically induced astigmatism was 0.53 D (Diopter with the Rule. The vertical component of astigmatism increased postoperatively than preoperatively. Horizontal component of astigmatism decreased in majority of cases postoperatively

  18. KIOM-79 Prevents Lens Epithelial Cell Apoptosis and Lens Opacification in Zucker Diabetic Fatty Rats

    Directory of Open Access Journals (Sweden)

    Junghyun Kim

    2011-01-01

    Full Text Available Damage of lens epithelial cells (LECs has been implicated in cataract formation. The aim of this study was to investigate the protective effect of KIOM-79, a combination of four plant extracts, on LECs. We examined the levels of advanced glycation end products (AGEs, nuclear factor-kappaB (NF-κB activation and inducible nitric oxide synthase (iNOS expression in LECs during cataract development using the Zucker diabetic fatty (ZDF rat, an animal model of type 2 diabetes. KIOM-79 was orally administered by gavage to ZDF rats once a day for 13 weeks. Apoptosis was detected by TUNEL assay, and NF-κB activation and iNOS expression were studied by southwestern histochemistry and immunohistochemistry, respectively. In diabetic cataractous lenses, TUNEL-positive LECs were markedly increased 20-fold, and AGEs were highly accumulated (2.7-fold in LECs. In addition, both NF-κB activation, and iNOS expression were significantly enhanced 3- to 5-fold, respectively, compared to levels found in normal ZL rats. However, the administration of KIOM-79 delayed the development of diabetic cataracts and prevented LEC apoptosis (70% through the inhibition of AGEs, NF-κB-activation and iNOS expression. These observations suggest that KIOM-79 is useful in inhibiting diabetic cataractogenesis and acts through an antiapoptotic mechanism to protect LECs from injury.

  19. 76 FR 47529 - Customer Clearing Documentation and Timing of Acceptance for Clearing; Correction

    Science.gov (United States)

    2011-08-05

    ... Street, NW., Washington, DC 20581. SUPPLEMENTARY INFORMATION: In FR Doc. 2011-19365 appearing on page... COMMISSION 17 CFR Parts 1, 23, and 39 RIN 3038-AD51 Customer Clearing Documentation and Timing of Acceptance... August 1, 2011, regarding Customer Clearing Documentation and Timing of Acceptance for Clearing....

  20. [Results of intraocular lens implantation in cataract complicated by medium and high myopia].

    Science.gov (United States)

    Plotnikova, Iu A; Chuprov, A D; Volkov, D V

    2001-01-01

    Results of surgical treatment of cataract complicated by medium and high myopia are analyzed. The main group consisted of 90 patients (96 eyes) subjected to extracapsular cataract extraction with implantation of posterior-chamber intraocular lenses and the reference group of 128 patients in whom cataract was extracted without implantation of artificial lens. The study included creation of a mathematical model of myopic eye with estimation of pressure fluctuations in various zones of the eye, developing during transposition of the vitreous during patient's movements (head movements, jumps, falling) and the damping effect of the lens in the ocular system. It was proven by mathematical calculations that transpositions of jelly fractions of the vitreous decreased by 70% in an eye with the lens in comparison with their transposition in aphakia. Clinical studies demonstrated the efficiency of intraocular correction of aphakia in high myopia: implantation of an intraocular lens decreases the risk of detachment of the retina during the postoperative period and helps attain the desired refraction. PMID:11765458

  1. A medieval fallacy: the crystalline lens in the center of the eye

    Directory of Open Access Journals (Sweden)

    Leffler CT

    2016-04-01

    Full Text Available Christopher T Leffler,1 Tamer M Hadi,2 Akrithi Udupa,1 Stephen G Schwartz,3 Daniel Schwartz1 1Department of Ophthalmology, Virginia Commonwealth University, Richmond, VA, 2Graduate School of Medicine, University of Tennessee Medical Center, Knoxville, TN, 3Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA Objective: To determine whether, as most modern historians have written, ancient Greco-Roman authors believed the crystalline lens is positioned in the center of the eye. Background: Historians have written that statements about cataract couching by Celsus, or perhaps Galen of Pergamon, suggested a centrally located lens. Celsus specifically wrote that a couching needle placed intermediate between the corneal limbus and the lateral canthus enters an empty space, presumed to represent the posterior chamber. Methods: Ancient ophthalmic literature was analyzed to understand where these authors believed the crystalline lens was positioned. In order to estimate where Celsus proposed entering the eye during couching, we prospectively measured the distance from the temporal corneal limbus to the lateral canthus in 30 healthy adults. Results: Rufus of Ephesus and Galen wrote that the lens is anterior enough to contact the iris. Galen wrote that the lens equator joins other ocular structures at the corneoscleral junction. In 30 subjects, half the distance from the temporal corneal limbus to the lateral canthus was a mean of 4.5 mm (range: 3.3–5.3 mm. Descriptions of couching by Celsus and others are consistent with pars plana entry of the couching needle. Anterior angulation of the needle would permit contact of the needle with the lens. Conclusion: Ancient descriptions of anatomy and couching do not establish the microanatomic relationships of the ciliary region with any modern degree of accuracy. Nonetheless, ancient authors, such as Galen and Rufus, clearly understood that the lens is located anteriorly

  2. MAGNITUDE OF POST OPERATIVE CORNEAL ASTIGMATISM AFTER PHACOEMULSIFICATION THROUGH 3.2MM TEMPORAL CLEAR CORNEAL INCISION

    OpenAIRE

    Neeraj

    2014-01-01

    Surgically induced astigmatism (SIA) is a common obstacle for achieving excellent uncorrected visual acuity after Phacoemulsification with implantation of foldable IOL. The aim of the study was to determine the magnitude of surgically induced post-operative astigmatism after phacoemulsification with intraocular lens implantation through a temporal clear corneal incision. This study included 16 eyes with senile cataract which were operated using phacoemulsification with imp...

  3. Surgically induced astigmatism after 3.0 mm temporal and nasal clear corneal incisions in bilateral cataract surgery

    OpenAIRE

    Je Hwan Yoon; Kyun-Hyung Kim; Jong Yeon Lee; Dong Heun Nam

    2013-01-01

    Aims: To compare the corneal refractive changes induced after 3.0 mm temporal and nasal corneal incisions in bilateral cataract surgery. Materials and Methods: This prospective study comprised a consecutive case series of 60 eyes from 30 patients with bilateral phacoemulsification that were implanted with a 6.0 mm foldable intraocular lens through a 3.0 mm horizontal clear corneal incision (temporal in the right eyes, nasal in the left eyes). The outcome measures were surgically induced astig...

  4. The Sloan Lens ACS Survey. V. The full ACS strong-lens sample

    NARCIS (Netherlands)

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Gavazzi, Raphael; Moustakas, Leonidas A.; Wayth, Randall; Schlegel, David J.

    2008-01-01

    We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey. All targets were selected for higher redshift emission lines and lower redshift c

  5. Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

    Directory of Open Access Journals (Sweden)

    Ladan Espandar

    2011-01-01

    Full Text Available Ladan Espandar1, Shameema Sikder2, Majid Moshirfar31Department of Ophthalmology, Tulane University, New Orleans, LA, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA; 3John A Moran Eye Center, University of Utah, Salt Lake City, UT, USAAbstract: Intraocular lens development is driven by higher patient expectations for ideal visual outcomes. The recently US Food and Drug Administration-approved Softec HD™ lens is an aspheric, hydrophilic acrylic intraocular lens (IOL. The hydrophilic design of the lens is optimized to address dysphotopsia while maintaining biocompatibility, optical clarity, resistance to damage, and resistance to biocontamination. Aspheric lenses decrease postoperative spherical aberration. The addition of the Softec lens provides clinicians with another option for IOL placement; however, randomized comparative studies of this lens to others already on the market remain to be completed.Keywords: hydrophilic acrylic intraocular lens, Softec HD intraocular lens, aspheric intraocular lens, IOL

  6. Oral Cavity Clear Cell Odontogenic Carcinoma.

    Science.gov (United States)

    Ginat, Daniel Thomas; Villaflor, Victoria; Cipriani, Nicole A

    2016-06-01

    A case of clear cell odontogenic carcinoma of the oral cavity is described in this sine qua non radiology-pathology correlation article. CT demonstrated a solid and cystic mass arising from the mandible. Histology demonstrated variably-sized nests of clear to pale eosinophilic cells with occasional central necrosis embedded in a hyalinized to fibrocellular stroma. The specimen was also positive for the characteristic rearrangement of the EWSR1 (22q12) locus in 93.5 % of interphase cells. PMID:25994920

  7. Small Incision Cataract Surgery (SICS with Clear Corneal Incision and SICS with Scleral Incision – A Comparative Study

    Directory of Open Access Journals (Sweden)

    Md Shafiqul Alam

    2014-01-01

    Full Text Available Background: Age related cataract is the leading cause of blindness and visual impairment throughout the world. With the advent of microsurgical facilities simple cataract extraction surgery has been replaced by small incision cataract surgery (SICS with posterior chamber intra ocular lens implant, which can be done either with clear corneal incision or scleral incision. Objective: To compare the post operative visual outcome in these two procedures of cataract surgery. Materials and method: This comparative study was carried out in the department of Ophthalmology, Delta Medical College & Hospital, Dhaka, Bangladesh, during the period of January 2010 to December 2012. Total 60 subjects indicated for age related cataract surgery irrespective of sex with the age range of 40-80 years with predefined inclusion and exclusion criteria were enrolled in the study. Subjects were randomly and equally distributed in 2 groups; Group A for SICS with clear corneal incision and group B for SICS with scleral incision. Post operative visual out come was evaluated by determining visual acuity and astigmatism in different occasions and was compared between groups. Statistical analysis was done by SPSS for windows version12. Results: The highest age incidence (43.3% was found between 61 to 70 years of age group. Among study subjects 40 were male and 20 were female. Preoperative visual acuity and astigmatism were evenly distributed between groups. Regarding postoperative unaided visual outcome, 6/12 or better visual acuity was found in 19.98% cases in group A and 39.6% cases in group B at 1st week. At 6th week 6/6 vision was found in 36.3% in Group A and 56.1% in Group B and 46.2% in group A and 66% in group B without and with correction respectively. With refractive correction, 6/6 vision was attained in 60% subjects of group A and 86.67% of group B at 8th week. Post operative visual acuity was statistically significant in all occasions. Postoperative astigmatism of

  8. Optical integration of Pancharatnam-Berry phase lens and dynamical phase lens

    Science.gov (United States)

    Ke, Yougang; Liu, Yachao; Zhou, Junxiao; Liu, Yuanyuan; Luo, Hailu; Wen, Shuangchun

    2016-03-01

    In the optical system, most elements such as lens, prism, and optical fiber are made of silica glass. Therefore, integrating Pancharatnam-Berry phase elements into silica glass has potential applications in the optical system. In this paper, we take a lens, for example, which integrates a Pancharatnam-Berry phase lens into a conventional plano-convex lens. The spin states and positions of focal points can be modulated by controlling the polarization states of the incident beam. The proposed lens has a high transmission efficiency, and thereby acts as a simple and powerful tool to manipulate spin photons. Furthermore, the method can be conveniently extended to the optical fiber and laser cavity, and may provide a route to the design of the spin-photonic devices.

  9. Clear-sky classification procedures and models using a world-wide data-base

    International Nuclear Information System (INIS)

    Clear-sky data need to be extracted from all-sky measured solar-irradiance dataset, often by using algorithms that rely on other measured meteorological parameters. Current procedures for clear-sky data extraction have been examined and compared with each other to determine their reliability and location dependency. New clear-sky determination algorithms are proposed that are based on a combination of clearness index, diffuse ratio, cloud cover and Linke's turbidity limits. Various researchers have proposed clear-sky irradiance models that rely on synoptic parameters; four of these models, MRM, PRM, YRM and REST2 have been compared for six world-wide-locations. Based on a previously-developed comprehensive accuracy scoring method, the models MRM, REST2 and YRM were found to be of satisfactory performance in decreasing order. The so-called Page radiation model (PRM) was found to underestimate solar radiation, even though local turbidity data were provided for its operation

  10. Clear Liquor Scrubbing with Anhydrite Production

    International Nuclear Information System (INIS)

    The objective of this project to develop an advanced flue gas desulfurization (FGD) process that has decreased capital and operating costs, higher SO2 removal efficiency, and better by-product solids quality than existing, commercially available technology. A clear liquor process (which uses a scrubbing liquid with no solids) will be used to accomplish this objective rather than a slurry liquor process (which contains solids). This clear liquor scrubbing (CLS) project is focused on three research areas: (1) Development of a clear liquor scrubbing process that uses a clear solution to remove SO2 from flue gas and can be operated under inhibited-oxidation conditions; (2) Development of an anhydrite process that converts precipitated calcium sulfite to anhydrous calcium sulfate (anhydrite); and (3) Development of an alkali/humidification process to remove HCl from flue gas upstream of the FGD system. The anhydrite process also can be retrofit into existing FGD systems to produce a valuable by-product as an alternative to gypsum. This fits well into another of FETC's PRDA objectives of developing an advanced byproduct recovery subsystem capable of transforming SO2 into a useable byproduct or high-volume valuable commodities of interest. This paper describes the proposed processes, outlines the test approach, and preliminary Phase I test results

  11. Lake Mead--clear and vital

    Science.gov (United States)

    Wessells, Stephen M.; Rosen, Michael

    2013-01-01

    “Lake Mead – Clear and Vital” is a 13 minute documentary relating the crucial role of science in maintaining high water quality in Lake Mead. The program was produced coincident with release of the Lakes Mead and Mohave Circular a USGS publication covering past and on-going research in the lakes and tributaries of the Lake Mead National Recreation Area.

  12. 77 FR 66219 - Clearing Agency Standards

    Science.gov (United States)

    2012-11-02

    ... Payment System Risk, 72 FR 2518 (Jan. 12, 2007). \\34\\ See FMI Report, supra note 32. II. Overview of... to clear credit default swaps. See Exchange Act Release Nos. 60372 (July 23, 2009), 74 FR 37748 (July 29, 2009), 61973 (Apr. 23, 2010), 75 FR 22656 (Apr. 29, 2010) and 63389 (Nov. 29, 2010), 75 FR...

  13. Plant Histology: Clearing and the Optical Section.

    Science.gov (United States)

    Freeman, H. E.

    1985-01-01

    Clearing is a simple and rapid technique in which 75 percent lactic acid is used to remove pigments and cytoplasmic contents of fresh leaves, enabling microscopic view of various internal leaf layers. Procedures for using the technique (which helps students gain a more thorough understanding of plant anatomy) are given. (DH)

  14. Nd:YAG laser photodisruption of the lens nucleus before phacoemulsification

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, E.H. Jr.; Logani, S.

    1987-10-15

    We studied the use of Q-switched Nd:YAG laser pulses to soften sclerotic lens nuclei before phacoemulsification. We obtained 105 lens nuclei from extracapsular cataract extractions, graded them for degree of sclerosis, and randomized them into laser treatment (53 lenses) or control groups (52 lenses). The treated lenses received laser pulses until confluent pits and clefts were visible. All lenses were phacoemulsified and the times recorded. Nd:YAG laser pretreatment decreased phacoemulsification time in all grades. In moderately sclerotic nuclei, average phacoemulsification time was reduced from 40.1 to 23.9 seconds (40.4%). The nuclei of ten lenses obtained from intracapsular cataract extractions were treated intracapsularly, and the posterior capsule was inadvertently ruptured in five.

  15. Models of the Cosmic Horseshoe Gravitational Lens

    CERN Document Server

    Dye, Simon; Belokurov, V; Warren, S J; Hewett, P

    2008-01-01

    We model the extremely massive and luminous lens galaxy in the Cosmic Horseshoe Einstein ring system, recently discovered in the Sloan Digital Sky Survey. We use the semi-linear method of Warren & Dye (2003), which pixelises the source surface brightness distribution, to invert the Einstein ring for sets of parameterised lens models. Here, the method is refined by exploiting Bayesian inference to optimise adaptive pixelisation of the source plane and to choose between three differently parameterised models: a singular isothermal ellipsoid, a power law model and a NFW profile. The most probable lens model is the power law with a volume mass density that scales as r^(-1.96+/-0.02) and an axis ratio of ~0.8. The mass within the Einstein ring (i.e., within a cylinder with projected distance of ~30 kpc from the centre of the lens galaxy) is (5.02+/-0.09)*10^12 M_solar, and the mass-to-light ratio is ~30. Even though the lens lies in a group of galaxies, the preferred value of the external shear is almost zero....

  16. Parametric modeling of zoom lens barrels

    Science.gov (United States)

    Pierce, Charles W.

    2001-12-01

    Today's customer requires zoom lens designs that are compact, inexpensive, and at six-sigma quality levels. While incorporating these customer requirements, a design team must often work within compressed design cycles and minimal product development budgets. These customer and project constraints, coupled with the inherent complexity of a zoom lens module, force the design team to try new and innovative techniques to deliver their products. This paper presents the methods used to develop lens barrels for several zoom lens module projects at Eastman Kodak Company. The lens barrel, a critical interface between the mechanical and optical systems, presented a technical barrier from both an engineering analysis and manufacturing perspective. The method used to overcome these barriers consisted of identifying several key functional parameters, creating a parameter-driven 3-D solid model in a commercially available CAD system, and then using the model to make iterative, data-driven design decisions while leveraging the model to create engineering drawings and the necessary prototypes and production tooling. As a result, the designs were able to meet their size, cost, and design cycle time requirements while realizing a better than anticipated first pass yield and quality level.

  17. Calculation of the transverse kicks generated by the bends of a hollow electron lens

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio

    2014-03-25

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam in high-energy accelerators. They were used in the Fermilab Tevatron collider for abort-gap clearing, beam-beam compensation, and halo scraping. A beam-beam compensation scheme based upon electron lenses is currently being implemented in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. This work is in support of a conceptual design of hollow electron beam scraper for the Large Hadron Collider. It also applies to the implementation of nonlinear integrable optics with electron lenses in the Integrable Optics Test Accelerator at Fermilab. We consider the axial asymmetries of the electron beam caused by the bends that are used to inject electrons into the interaction region and to extract them. A distribution of electron macroparticles is deposited on a discrete grid enclosed in a conducting pipe. The electrostatic potential and electric fields are calculated using numerical Poisson solvers. The kicks experienced by the circulating beam are estimated by integrating the electric fields over straight trajectories. These kicks are also provided in the form of interpolated analytical symplectic maps for numerical tracking simulations, which are needed to estimate the effects of the electron lens imperfections on proton lifetimes, emittance growth, and dynamic aperture. We outline a general procedure to calculate the magnitude of the transverse proton kicks, which can then be generalized, if needed, to include further refinements such as the space-charge evolution of the electron beam, magnetic fields generated by the electron current, and longitudinal proton dynamics.

  18. Visual and Refractive Outcomes of a Toric Presbyopia-Correcting Intraocular Lens

    OpenAIRE

    Epitropoulos, Alice T.

    2016-01-01

    Purpose. To evaluate outcomes in astigmatic patients implanted with the Trulign (Bausch + Lomb) toric presbyopia-correcting intraocular lens (IOL) during cataract surgery in a clinical practice setting. Methods. Retrospective study in 40 eyes (31 patients) that underwent cataract extraction and IOL implantation in a procedure using intraoperative wavefront aberrometry guidance (ORA system). Endpoints included uncorrected visual acuity (VA), reduction in refractive cylinder, accuracy to target...

  19. Social Norms and Behavior in the Local Commons Through the Lens of Field Experiments

    OpenAIRE

    Cardenas, Juan-Camilo

    2009-01-01

    Behavior in the local commons is usually embedded in a context of regulations and social norms that the group of users face. Such norms and rules affect how individuals value material and non-material incentives and therefore determine their decision to cooperate or over extract the resources from the common-pool. This paper discusses the importance of social norms in shaping behavior in the commons through the lens of experiments, and in particular experiments conducted in the field with peo...

  20. Modified Small Incision Cataract Surgery and Intraocular Lens Implantation in HIV Patients

    OpenAIRE

    Kagmeni Giles; Christelle Domngang; Georges Nguefack-Tsague; Ebana Mvogo Come; Peter Wiedemann

    2015-01-01

    AIM To describe a surgical technique suitable for cataract surgery in regions with a high prevalence of HIV infection. METHODS We reviewed the medical records of 20 consecutive AIDS patients with cataract who underwent modified small-incision cataract surgery (mSICS) with posterior chamber lens implantation. Classic extracapsular cataract extraction (ECCE) was compared to mSICS. The number of potentially risky steps for contamination during surgery and duration of surgery were analyzed. A ris...

  1. Efficient flat metasurface lens for terahertz imaging.

    Science.gov (United States)

    Yang, Quanlong; Gu, Jianqiang; Wang, Dongyang; Zhang, Xueqian; Tian, Zhen; Ouyang, Chunmei; Singh, Ranjan; Han, Jiaguang; Zhang, Weili

    2014-10-20

    Metamaterials offer exciting opportunities that enable precise control of amplitude, polarization and phase of the light beam at a subwavelength scale. A gradient metasurface consists of a class of anisotropic subwavelength metamaterial resonators that offer abrupt amplitude and phase changes, thus enabling new applications in optical device design such as ultrathin flat lenses. We propose a highly efficient gradient metasurface lens based on a metal-dielectric-metal structure that operates in the terahertz regime. The proposed structure consists of slotted metallic resonator arrays on two sides of a thin dielectric spacer. By varying the geometrical parameters, the metasurface lens efficiently manipulates the spatial distribution of the terahertz field and focuses the beam to a spot size on the order of a wavelength. The proposed flat metasurface lens design is polarization insensitive and works efficiently even at wide angles of incidence. PMID:25401626

  2. 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.

  3. The Frontier Fields Lens Modeling Comparison Project

    CERN Document Server

    Meneghetti, M; Coe, D; Contini, E; De Lucia, G; Giocoli, C; Acebron, A; Borgani, S; Bradac, M; Diego, J M; Hoag, A; Ishigaki, M; Johnson, T L; Jullo, E; Kawamata, R; Lam, D; Limousin, M; Liesenborgs, J; Oguri, M; Sebesta, K; Sharon, K; Williams, L L R; Zitrin, A

    2016-01-01

    Gravitational lensing by clusters of galaxies offers a powerful probe of their structure and mass distribution. Deriving a lens magnification map for a galaxy cluster is a classic inversion problem and many methods have been developed over the past two decades to solve it. Several research groups have developed techniques independently to map the predominantly dark matter distribution in cluster lenses. While these methods have all provided remarkably high precision mass maps, particularly with exquisite imaging data from the Hubble Space Telescope (HST), the reconstructions themselves have never been directly compared. In this paper, we report the results of comparing various independent lens modeling techniques employed by individual research groups in the community. Here we present for the first time a detailed and robust comparison of methodologies for fidelity, accuracy and precision. For this collaborative exercise, the lens modeling community was provided simulated cluster images -- of two clusters Are...

  4. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... the skull base. Conclusion: These results indicate that it is possible to reduce the radiation dose to the eye lens without loss of diagnostic information in the scan by optimizing positioning of the head....

  5. An inverse and analytic lens design method

    CERN Document Server

    Lu, Yang

    2016-01-01

    Traditional lens design is a numerical and forward process based on ray tracing and aberration theory. This method has limitations because the initial configuration of the lens has to be specified and the aberrations of the lenses have to considered. This paper is an initial attempt to investigate an analytic and inverse lens design method, called Lagrange, to overcome these barriers. Lagrange method tries to build differential equations in terms of the system parameters and the system input and output (object and image). The generalized Snell's law in three dimensional space and the normal of a surface in fundamental differential geometry are applied. Based on the Lagrange method equations for a single surface system are derived which can perfectly image a point object.

  6. Catadioptric aberration correction in cathode lens microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tromp, R.M. [IBM T.J. Watson Research Center, PO Box 218, Yorktown Heights, NY 10598 (United States); Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

    2015-04-15

    In this paper I briefly review the use of electrostatic electron mirrors to correct the aberrations of the cathode lens objective lens in low energy electron microscope (LEEM) and photo electron emission microscope (PEEM) instruments. These catadioptric systems, combining electrostatic lens elements with a reflecting mirror, offer a compact solution, allowing simultaneous and independent correction of both spherical and chromatic aberrations. A comparison with catadioptric systems in light optics informs our understanding of the working principles behind aberration correction with electron mirrors, and may point the way to further improvements in the latter. With additional developments in detector technology, 1 nm spatial resolution in LEEM appears to be within reach. - Highlights: • The use of electron mirrors for aberration correction in LEEM/PEEM is reviewed. • A comparison is made with similar systems in light optics. • Conditions for 1 nm spatial resolution are discussed.

  7. Catadioptric aberration correction in cathode lens microscopy

    International Nuclear Information System (INIS)

    In this paper I briefly review the use of electrostatic electron mirrors to correct the aberrations of the cathode lens objective lens in low energy electron microscope (LEEM) and photo electron emission microscope (PEEM) instruments. These catadioptric systems, combining electrostatic lens elements with a reflecting mirror, offer a compact solution, allowing simultaneous and independent correction of both spherical and chromatic aberrations. A comparison with catadioptric systems in light optics informs our understanding of the working principles behind aberration correction with electron mirrors, and may point the way to further improvements in the latter. With additional developments in detector technology, 1 nm spatial resolution in LEEM appears to be within reach. - Highlights: • The use of electron mirrors for aberration correction in LEEM/PEEM is reviewed. • A comparison is made with similar systems in light optics. • Conditions for 1 nm spatial resolution are discussed

  8. Laser light scattering in eye lens model

    Science.gov (United States)

    Larionova, Nadezhda L.; Maksimova, Irina L.; Kochubey, Vyacheslav I.

    2000-11-01

    Theoretical investigations of laser light radiation scattered by eye lens model as a system of spheres with various parameters were performed on the base of Mie theory of electromagnetic scattering by a single sphere. The calculations were performed for systems of particles whose coordinates were specifically realized in random fashion according to the specified probabilities defined by the approximation of hard spheres. The modeling of lens biotissue was carried out by using of medical data about internal structure of lens of human and some animals. In general the researchable model presents the system of homogeneous spherical particles those are randomly distributed in the layer of thickness. We study the optical properties such as scattering effective cross-section and function of correlation in different models.

  9. Eye lens dose in interventional cardiology.

    Science.gov (United States)

    Principi, S; Delgado Soler, C; Ginjaume, M; Beltran Vilagrasa, M; Rovira Escutia, J J; Duch, M A

    2015-07-01

    The ICRP has recently recommended reducing the occupational exposure dose limit for the lens of the eye to 20 mSv y(-1), averaged over a period of 5 y, with no year exceeding 50 mSv, instead of the current 150 mSv y(-1). This reduction will have important implications for interventional cardiology and radiology (IC/IR) personnel. In this work, lens dose received by a staff working in IC is studied in order to determine whether eye lens dose monitoring or/and additional radiological protection measures are required. Eye lens dose exposure was monitored in 10 physicians and 6 nurses. The major IC procedures performed were coronary angiography and percutaneous transluminal coronary angioplasty. The personnel were provided with two thermoluminescent dosemeters (TLDs): one calibrated in terms of Hp(3) located close to the left ear of the operator and a whole-body dosemeter calibrated in terms of Hp(10) and Hp(0.07) positioned on the lead apron. The estimated annual eye lens dose for physicians ranged between 8 and 60 mSv, for a workload of 200 procedures y(-1). Lower doses were collected for nurses, with estimated annual Hp(3) between 2 and 4 mSv y(-1). It was observed that for nurses the Hp(0.07) measurement on the lead apron is a good estimate of eye lens dose. This is not the case for physicians, where the influence of both the position and use of protective devices such as the ceiling shield is very important and produces large differences among doses both at the eyes and on the thorax. For physicians, a good correlation between Hp(3) and dose area product is shown. PMID:25809107

  10. Analytic Models of Plausible Gravitational Lens Potentials

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-05-04

    Gravitational lenses on galaxy scales are plausibly modeled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic 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. Emphasizing 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 Sersic 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 modeled, 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.

  11. Eye lens dose in interventional cardiology

    International Nuclear Information System (INIS)

    The ICRP has recently recommended reducing the occupational exposure dose limit for the lens of the eye to 20 mSv y-1 , averaged over a period of 5 y, with no year exceeding 50 mSv, instead of the current 150 mSv y-1 . This reduction will have important implications for interventional cardiology and radiology (IC/IR) personnel. In this work, lens dose received by a staff working in IC is studied in order to determine whether eye lens dose monitoring or/and additional radiological protection measures are required. Eye lens dose exposure was monitored in 10 physicians and 6 nurses. The major IC procedures performed were coronary angiography and percutaneous transluminal coronary angioplasty. The personnel were provided with two thermoluminescent dosemeters (TLDs): one calibrated in terms of Hp(3) located close to the left ear of the operator and a whole-body dosemeter calibrated in terms of Hp(10) and Hp(0.07) positioned on the lead apron. The estimated annual eye lens dose for physicians ranged between 8 and 60 mSv, for a workload of 200 procedures y-1. Lower doses were collected for nurses, with estimated annual Hp(3) between 2 and 4 mSv y-1. It was observed that for nurses the Hp(0.07) measurement on the lead apron is a good estimate of eye lens dose. This is not the case for physicians, where the influence of both the position and use of protective devices such as the ceiling shield is very important and produces large differences among doses both at the eyes and on the thorax. For physicians, a good correlation between Hp(3) and dose area product is shown. (authors)

  12. Roadmap-Based Level Clearing of Buildings

    KAUST Repository

    Rodriguez, Samuel

    2011-01-01

    In this paper we describe a roadmap-based approach for a multi-agent search strategy to clear a building or multi-story environment. This approach utilizes an encoding of the environment in the form of a graph (roadmap) that is used to encode feasible paths through the environment. The roadmap is partitioned into regions, e.g., one per level, and we design region-based search strategies to cover and clear the environment. We can provide certain guarantees within this roadmap-based framework on coverage and the number of agents needed. Our approach can handle complex and realistic environments where many approaches are restricted to simple 2D environments. © 2011 Springer-Verlag.

  13. Clear cell odontogenic carcinoma: A rare case

    Directory of Open Access Journals (Sweden)

    Garima Jain

    2015-01-01

    Full Text Available Clear cell odontogenic carcinoma is a rare neoplasm with very few cases reported in the literature. We report a case of a 50-year-old female patient with the malignancy at a less common location. Diagnosis was given based on the histopathologic findings. The demographic data and understanding for this tumor needs to be strengthened by reporting all new cases, which are diagnosed, in literature.

  14. Imaging of ovarian clear cell carcinoma

    International Nuclear Information System (INIS)

    The aim of this study is to examine the appearance of ovarian clear cell adenocarcinoma (OCCA) on MR, CT, US. In 39 cases with OCCA, the imaging characteristics of OCCA were evaluated morphologically and classified into three groups, that was, monomural nodule type, multi-mural nodule type and predominantly solid type. Forty-three percent of the patients had endometriosis. Contrast material-enhanced MRI was the most useful method for diagnosis of OCCA. (author)

  15. Renal Clear Cell Carcinoma and Tonsil Metastasis

    OpenAIRE

    Dario Marcotullio; Giannicola Iannella; Gian Franco Macri; Caterina Marinelli; Melissa Zelli; Giuseppe Magliulo

    2013-01-01

    Renal cell carcinoma is the most common renal tumor in adults. Clear cell carcinoma represents 85% of all histological subtypes. In February 2012 a 72-year-old woman came to our department due to the appearance of massive hemoptysis and pharyngodinia. Previously, this patient was diagnosed with a renal cell carcinoma treated with left nephrectomy. We observed an exophytic, grayish, and ulcerated mass in the left tonsillar lodge and decided to subject the patient to an immediate tonsillectomy....

  16. Internet compromise clears way for WSIS agreement

    CERN Document Server

    Ermert, M

    2003-01-01

    A working group under the leadership of United Nations Secretary General Kofi Annan himself will try to resolve the deep differences on the question of Internet governance, officials said here. The group, whose exact membership wasn't immediately clear, is to propose a solution to the controversial issue that has given negotiators at the World Summit of the Information Society (WSIS) a headache (1/2 page).

  17. Imaging of ovarian clear cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Toshihiko; Sawano, Seishi; Yamada, Keiko [Japanese Foundation for Cancer Research, Tokyo (Japan). Hospital] (and others)

    1999-12-01

    The aim of this study is to examine the appearance of ovarian clear cell adenocarcinoma (OCCA) on MR, CT, US. In 39 cases with OCCA, the imaging characteristics of OCCA were evaluated morphologically and classified into three groups, that was, monomural nodule type, multi-mural nodule type and predominantly solid type. Forty-three percent of the patients had endometriosis. Contrast material-enhanced MRI was the most useful method for diagnosis of OCCA. (author)

  18. 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.

  19. Near field imaging from multilayer lens.

    Science.gov (United States)

    Li, Guixin; Li, Jensen; Tam, H L; Chan, C T; Cheah, K W

    2011-12-01

    Multilayer superlens has been reported that it had advantages over the single metal layer superlens. In this work, single silver layer and Ag-SiO2 multilayer superlens devices working at wavelength of 365 nm were fabricated using standard photolithography method. Grating objects with line/space (190 nm/190 nm) resolution could be resolved through both kinds of lens structures with working distance up to 128 nm. However, Ag-SiO2 multilayer lens shows higher transmittance and image contrast than the single silver layer device, the experimental result proves the theoretical calculation. PMID:22408982

  20. Fabrication of an unusual mosaic lens

    International Nuclear Information System (INIS)

    The design philosophy and the construction techniques to make a novel mosaic lens to collect Cerenkow radiation are described. The lens blanks were rough cut into segments by a water jet. The segments were cut to the final inner and outer diameters by ultrasonically assisted machining, an unusual new technique developed at the Los Alamos National Laboratory. The technology will soon be available to the public through Sonic Mill, Inc., 3820 Academy Parkway North, NE, Albuquerque, N.M. 87109. The advantage of ultrasonically assisted machining lies in rapid, accurate shaping of brittle materials such as ceramics and glass, which can by this technique, be shaped about as fast as aluminum

  1. Pulse transformer for the AA lithium lens

    CERN Multimedia

    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).

  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. An "ESA-affordable" Laue-lens

    DEFF Research Database (Denmark)

    Lund, Niels

    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......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...

  4. Herniation of the anterior lens capsule

    Directory of Open Access Journals (Sweden)

    Pereira Nolette

    2007-01-01

    Full Text Available Herniation of the anterior lens capsule is a rare abnormality in which the capsule bulges forward in the pupillary area. This herniation can be mistaken for an anterior lenticonus where both the capsule and the cortex bulge forward. The exact pathology behind this finding is still unclear. We report the clinical, ultrasound biomicroscopy (UBM and histopathological findings of a case of herniation of the anterior lens capsule. UBM helped to differentiate this entity from anterior lenticonus. Light microscopy revealed capsular splitting suggestive of capsular delamination and collection of fluid (aqueous in the area of herniation giving it a characteristic appearance.

  5. Rapid radiative clearing of protoplanetary discs

    CERN Document Server

    Haworth, Thomas J; Owen, James E

    2015-01-01

    The lack of observed transition discs with inner gas holes of radii greater than ~50AU implies that protoplanetary discs dispersed from the inside out must remove gas from the outer regions rapidly. We investigate the role of photoevaporation in the final clearing of gas from low mass discs with inner holes. In particular, we study the so-called "thermal sweeping" mechanism which results in rapid clearing of the disc. Thermal sweeping was originally thought to arise when the radial and vertical pressure scale lengths at the X-ray heated inner edge of the disc match. We demonstrate that this criterion is not fundamental. Rather, thermal sweeping occurs when the pressure maximum at the inner edge of the dust heated disc falls below the maximum possible pressure of X-ray heated gas (which depends on the local X-ray flux). We derive new critical peak volume and surface density estimates for rapid radiative clearing which, in general, result in rapid dispersal happening less readily than in previous estimates. Thi...

  6. Experimental characterization of the Clear-PEM scanner spectrometric performance

    Science.gov (United States)

    Bugalho, R.; Carriço, B.; Ferreira, C. S.; Frade, M.; Ferreira, M.; Moura, R.; Ortigão, C.; Pinheiro, J. F.; Rodrigues, P.; Rolo, I.; Silva, J. C.; Trindade, A.; Varela, J.

    2009-10-01

    In the framework of the Clear-PEM project for the construction of a high-resolution and high-specificity scanner for breast cancer imaging, a Positron Emission Mammography tomograph has been developed and installed at the Instituto Português de Oncologia do Porto hospital. The Clear-PEM scanner is mainly composed by two planar detector heads attached to a robotic arm, trigger/data acquisition electronics system and computing servers. The detector heads hold crystal matrices built from 2 × 2 × 20 mm3 LYSO:Ce crystals readout by Hamamatsu S8550 APD arrays. The APDs are optically coupled to both ends of the 6144 crystals in order to extract the DOI information for each detected event. Each one of 12288 APD's pixels is read and controlled by Application Specific Integrated Circuits water-cooled by an external cooling unit. The Clear-PEM frontend boards innovative design results in a unprecedented integration of the crystal matrices, APDs and ASICs, making Clear-PEM the PET scanner with the highest number of APD pixels ever integrated so far. In this paper, the scanner's main technical characteristics, calibration strategies and the first spectrometric performance evaluation in a clinical environment are presented. The first commissioning results show 99.7% active channels, which, after calibration, have inter-pixel and absolute gain distributions with dispersions of, respectively, 12.2% and 15.3%, demonstrating that despite the large number of channels, the system is uniform. The mean energy resolution at 511 keV is of 15.9%, with a 8.8% dispersion, and the mean CDOI-1 is 5.9%/mm, with a 7.8% dispersion. The coincidence time resolution, at 511 keV, for a energy window between 400 and 600 keV, is 5.2 ns FWHM.

  7. Provision of dosimeters by official monitoring services for eye lens dose estimation

    International Nuclear Information System (INIS)

    Recent epidemiological studies are implying that the radio sensitivity of the eye lens is much higher than supposed in the past. International recommendations and standards demand to lower down the annual limit of the eye lens organ dose to 20 mSv. Since about 10 years German monitoring services offer partial-body dosimeters fixed on the head or on glasses for monitoring the eye lens dose. These dosimeters are optimized to measure the (surface) personal dose equivalent Hp(0,07) from 0,5 mSv up to 10 Sv, which clearly overestimate the organ dose of the eye lens. With special features like different calibrations partial-body dosimeters should be applicable for legal dosimetry to avoid the development of special Hp(3) dosimeters. Accepting the right way for wearing these dosimeters it is important to get the right results. Practical experiences are shown with measuring results and the difficulties of rounding the exact measuring values to discrete dose steps. Closing this article we point to still missing legal basis and open questions regarding to type testing procedures. (orig.)

  8. Aligning and measuring the curvature and thickness of high-precision lens

    Science.gov (United States)

    Wu, Kun-Huan; Chang, Shenq-Tsong; Hsu, Ming-Ying; Huang, Ting-Ming; Hsu, Wei-Yao; Tseng, Shih-Feng

    2015-09-01

    The radius of curvature is one of the most important specifications for spherical optics [1]. There are several methods and devices currently on the market that can be used to measure it, including optical level, non-contact laser interferometer (Interferometer), a probe-contact profiler (Profilometer), the centering machine and three-point contact ball diameter meter (Spherometer). The amount that can be measured with a radius of curvature of the lens aperture range depends on the interferometer standard lens f / number and lens of R / number (radius of curvature divided by the clear aperture of the spherical surface ratio between them). Unfortunately, for lens with diameter greater than 300 mm, the device is limited by the size of the holding fixture lenses or space. This paper aims to provide a novel surface contour detection method and machine, named "CMM spherometry by probe compensation," to measure the radius and thickness of the curvature of the optical surface by a coordinate measurement machine (CMM). In order to obtain more accurate optimization results, we used probe and temperature compensation to discuss the effect. The trace samples and the measurement results of CMM and the centering machine, which has top and bottom autocollimators, are compared.

  9. Growth of the eye lens: II. Allometric studies

    OpenAIRE

    Augusteyn, Robert C.

    2014-01-01

    Purpose The purpose of this study was to examine the ontogeny and phylogeny of lens growth in a variety of species using allometry. Methods Data on the accumulation of wet and/or dry lens weight as a function of bodyweight were obtained for 40 species and subjected to allometric analysis to examine ontogenic growth and compaction. Allometric analysis was also used to compare the maximum adult lens weights for 147 species with the maximum adult bodyweight and to compare lens volumes calculated...

  10. Floating anterior lens capsule: an unusual case of true exfoliation

    OpenAIRE

    Riffle, John

    2010-01-01

    A rare case of delamination and replication of the anterior lens capsule into prominent floating folds in the anterior chamber approximately 55 years after a penetrating injury to the eye and anterior lens capsule is reported. Classically, true exfoliation of the anterior lens capsule has been reported in individuals who have been exposed to intense heat over a prolonged period. However, more recently cases of true exfoliation of the anterior lens capsule have been reported in patients who ha...

  11. Superior Lens Coloboma with Superior Rectus Palsy and Congenital Ptosis

    OpenAIRE

    Jethani, Jitendra; Vishal R. Sharma; Marwah, Kenshuk

    2009-01-01

    A lens coloboma is characterized by the lens tissue's notching at the equator. It is usually inferior-nasal else it is called an atypical coloboma. We report a young male who presented with a superior lens coloboma, an elevation deficit and moderate ptosis, left eye. As superior rectus and levator muscles are derived from the neural crest cell we propose, genetically, there may be an association between the lens coloboma and the superior rectus/levator muscle underaction via an anomalous home...

  12. Achromatic Fresnel Lens with Improved Efficiency for PV Systems

    OpenAIRE

    Mario González Montes; Juan Carlos Martínez-Antón; Daniel Vázquez Moliní; Antonio Álvarez Fernandez-Balbuena; Bernabeu, E.

    2014-01-01

    This work is aimed to design and evaluate different achromatic Fresnel lens solutions capable of operating as concentrators aimed at photovoltaic cells systems. Throughout this study, the theoretical parametric design of the achromatic lens will be shown together with a series of simulations to verify the performance of each lens topology. The results will be compared with a standard Fresnel lens to ascertain the validity and effectiveness of the obtained design. Finally, a novel kind of hybr...

  13. Cataract Extraction in High Myopic Eyes

    OpenAIRE

    Wan-Chen Ku; Lan-Hsin Chuang; Chi-Chun Lai

    2002-01-01

    Background: According to the high prevalence of myopia in Taiwan, we analyze theadopted cataract extractions, identify predicting factors for postoperativevision, and to assess the incidence of retinal complications after Nd: YAGlaser capsulotomy in high myopic eyes.Methods: One hundred and twenty-five eyes, which the axial lengths were longer than26 mm, following cataract extraction were enrolled. Surgeries adoptedincluded phacoemulsification with intraocular lens implantation, extracapsular...

  14. Progression of diabetic retinopathy after cataract extraction.

    OpenAIRE

    Pollack, A; Dotan, S.; Oliver, M.

    1991-01-01

    The course of diabetic retinopathy following cataract extraction was studied retrospectively in 89 patients (89 eyes). Cataract extraction was extracapsular in 12 eyes (13.5%), extracapsular with intraocular lens implantation in 37 (41.6%), and intracapsular in 40 (45%). In 55 eyes (61.8%) there was no change in the retinal status after surgery, and in 34 (38.2%) there was progression of diabetic retinopathy. In the eyes showing progression there was appearance or aggravation of non-prolifera...

  15. Medical Marijuana: Clearing Away the Smoke

    OpenAIRE

    Grant, Igor; Atkinson, J. Hampton; Gouaux, Ben; Wilsey, Barth

    2012-01-01

    Recent advances in understanding of the mode of action of tetrahydrocannabinol and related cannabinoid in-gredients of marijuana, plus the accumulating anecdotal reports on potential medical benefits have spurred increasing re-search into possible medicinal uses of cannabis. Recent clinical trials with smoked and vaporized marijuana, as well as other botanical extracts indicate the likelihood that the cannabinoids can be useful in the management of neuropathic pain, spasticity due to multiple...

  16. The Clear Creek Envirohydrologic Observatory: From Vision Toward Reality

    Science.gov (United States)

    Just, C.; Muste, M.; Kruger, A.

    2007-12-01

    As the vision of a fully-functional Clear Creek Envirohydrologic Observatory comes closer to reality, the opportunities for significant watershed science advances in the near future become more apparent. As a starting point to approaching this vision, we focused on creating a working example of cyberinfrastructure in the hydrologic and environmental sciences. The system will integrate a broad range of technologies and ideas: wired and wireless sensors, low power wireless communication, embedded microcontrollers, commodity cellular networks, the internet, unattended quality assurance, metadata, relational databases, machine-to-machine communication, interfaces to hydrologic and environmental models, feedback, and external inputs. Hardware: An accomplishment to date is "in-house" developed sensor networking electronics to compliment commercially available communications. The first of these networkable sensors are dielectric soil moisture probes that are arrayed and equipped with wireless connectivity for communications. Commercially available data logging and telemetry-enabled systems deployed at the Clear Creek testbed include a Campbell Scientific CR1000 datalogger, a Redwing 100 cellular modem, a YA Series yagi antenna, a NP12 rechargeable battery, and a BP SX20U solar panel. This networking equipment has been coupled with Hach DS5X water quality sondes, DTS-12 turbidity probes and MicroLAB nutrient analyzers. Software: Our existing data model is an Arc Hydro-based geodatabase customized with applications for extraction and population of the database with third party data. The following third party data are acquired automatically and in real time into the Arc Hydro customized database: 1) geophysical data: 10m DEM and soil grids, soils; 2) land use/land cover data; and 3) eco-hydrological: radar-based rainfall estimates, stream gage, streamlines, and water quality data. A new processing software for data analysis of Acoustic Doppler Current Profilers (ADCP

  17. 21 CFR 886.1425 - Lens measuring instrument.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1425 Lens measuring instrument. (a) Identification. A lens measuring instrument is an AC-powered device intended to measure the power of lenses... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Lens measuring instrument. 886.1425 Section...

  18. 21 CFR 886.5916 - Rigid gas permeable contact lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rigid gas permeable contact lens. 886.5916 Section... lens. (a) Identification. A rigid gas permeable contact lens is a device intended to be worn directly against the cornea of the eye to correct vision conditions. The device is made of various materials,...

  19. 21 CFR 886.4300 - Intraocular lens guide.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4300 Intraocular lens guide. (a) Identification. An intraocular lens guide is a device intended to be inserted into the eye during surgery to direct... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens guide. 886.4300 Section...

  20. 21 CFR 886.1405 - Ophthalmic trial lens set.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens set. 886.1405 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1405 Ophthalmic trial lens set. (a) Identification. An ophthalmic trial lens set is a device that is a set of lenses of various dioptric...

  1. Once-punctured tori and knots in lens spaces

    OpenAIRE

    Baker, Kenneth L.

    2006-01-01

    We determine the non-null homologous knots in lens spaces whose exteriors contain properly embedded once-punctured tori. All such knots arise as surgeries on the Whitehead link and are grid number 1 in their lens spaces. As a corollary, we classify once-punctured torus bundles that admit a lens space filling.

  2. 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...

  3. 21 CFR 886.1410 - Ophthalmic trial lens clip.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens clip. 886.1410 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1410 Ophthalmic trial lens clip. (a) Identification. An ophthalmic trial lens clip is a device intended to hold prisms, spheres, cylinders,...

  4. Determination of human lens capsule permeability and its feasibility as a replacement for Bruch's membrane.

    Science.gov (United States)

    Lee, Christina J; Vroom, Jonathan A; Fishman, Harvey A; Bent, Stacey F

    2006-03-01

    We have investigated human anterior lens capsule as a potential replacement for Bruch's membrane as a treatment for age-related macular degeneration. Any substrate to replace Bruch's membrane should possess certain characteristics to maintain proper function of the overlying retina. One of the important properties of Bruch's membrane is allowing the flow of nutrients and waste between the retinal pigment epithelium and the choriocapillaris. Here, we measured the permeability of the lens capsule by studying the diffusion of various molecular weight FITC-dextran molecules. Expressions for extraction of diffusion coefficients from concentration vs. time data from a blind-well chamber apparatus were derived for both a single and double membrane experiments. The diffusion coefficients in the lens capsule were found to be in the range of 10(-6) to 10(-10)cm2/s. We demonstrated a power law relationship, with the diffusion coefficient possessing a -0.6 order dependence on molecular weight. The molecular weight exclusion limit was determined to be 150+/-40 kDa. We have compared this value with reported values of Bruch's membrane molecular weight exclusion limit and find that the lens capsule has the potential to act as a substitute Bruch's membrane. PMID:16199085

  5. Feature matching method study for uncorrected fish-eye lens image

    Science.gov (United States)

    Zhang, Baofeng; Jia, Yanhui; Röning, Juha; Feng, Weijia

    2015-01-01

    Because of the further from the center of image the lower resolution and the severe non-linear distortion are the characteristics of uncorrected fish-eye lens image, the traditional feature matching method can't achieve good performance in the applications of fish-eye lens, which correct distortion firstly and then matches the features in image. Center-symmetric Local Binary Pattern (CS-LBP) is a kind of descriptor based on grayscale information from neighborhood, which has high ability of grayscale invariance and rotation invariance. In this paper, CS-LBP will be combined with Scale Invariant Feature Transform (SIFT) to solve the problem of feature point matching on uncorrected fish-eye image. We first extract the interest points in the pair of fish-eye images by SIFT, and then describe the corresponding regions of the interest points through CS-LBP. Finally the similarity of the regions will be evaluated using the chi-square distance to get the only pair of points. For the specified interest point, the corresponding point in another image can be found out. The experimental results show that the proposed method achieves a satisfying matching performance in uncorrected fish-eye lens image. The study of this article will be useful to enhance the applications of fish-eye lens in the field of 3D reconstruction and panorama restoration.

  6. Oxidation of Lipids and Proteins in Lens and Blood Plasma of Rats in Ageing

    Directory of Open Access Journals (Sweden)

    Ivanova I.P.

    2011-09-01

    Full Text Available The aim of the study is to assess the intensity of oxidation of lipids and proteins in lens and blood plasma of Wistar rats in ageing. Materials and Methods. The experiments were carried out on 25 Wistar male rats of four age groups: 5, 12, 24 and 36 months. Materials for study were lens and blood plasma. Lipids were extracted using Folch partition. The content of diene and triene conjugates was assessed by means of spectrophotometry. The level of Schiff’s bases was studied according to fluorescence intensity, malon dialdehyde concentration — according to the intensity of interaction with thiobarbituric acid. Potentiality of substrate oxidation in specimen was assessed using the method of induced chemoluminescence, and the degree of protein oxidative modification was assessed according to the level of carbonyl derivatives with 2.4-dinitrophenylhydrasine. The investigation of the content of total lipids and total proteins were carried out using “Bio-Test Total Lipids” and “Total Protein-Vital”. Results. The processes of lipid peroxidation of lens membranes are increasing in animals aged 5—12 months and decreasing in the period of 12—24 months. The level of lipid peroxidation in blood plasma has an expressed tendency for increasing in ageing. Over the years, there is the level decrease of carbonyl derivatives of aminoacids of lens proteins and the tendency for the increase of oxidative modification of proteins in blood plasma.

  7. SHARP - III: First Use Of Adaptive Optics Imaging To Constrain Cosmology With Gravitational Lens Time Delays

    CERN Document Server

    Chen, Geoff C F; Wong, Kenneth C; Fassnacht, Christopher D; Chiueh, Tzihong; Halkola, Aleksi; Hu, I Shing; Auger, Matthew W; Koopmans, Leon V E; Lagattuta, David J; McKean, John P; Vegetti, Simona

    2016-01-01

    Accurate and precise measurements of the Hubble constant are critical for testing our current standard cosmological model and revealing possibly new physics. With Hubble Space Telescope (HST) imaging, each strong gravitational lens system with measured time delays can allow one to determine the Hubble constant with an uncertainty of $\\sim 7\\%$. Since HST will not last forever, we explore adaptive-optics (AO) imaging as an alternative that can provide higher angular resolution than HST imaging but has a less stable point spread function (PSF) due to atmospheric distortion. To make AO imaging useful for time-delay-lens cosmography, we develop a method to extract the unknown PSF directly from the imaging of strongly lensed quasars. In a blind test with two mock data sets created with different PSFs, we are able to recover the important cosmological parameters (time-delay distance, external shear, lens mass profile slope, and total Einstein radius). Our analysis of the Keck AO image of the strong lens system RXJ1...

  8. Lens induced glaucomas - visual results and risk factors for final visual acuity

    Directory of Open Access Journals (Sweden)

    Prajna N

    1996-01-01

    Full Text Available Lens induced glaucomas are a common occurence in India. An attempt was made to understand the clinical modes of presentation and post operative visual results in 93 patients with lens induced glaucoma, 49 phacomorphic and 44 phacolytic, attending our institute during 1994. All these patients were subjected to a planned extracapsular cataract extraction. Forty four percent had a posterior chamber intraocular lens implantation following surgery. Fifty seven percent eyes with phacomorphic glaucoma and 61% with phacolytic glaucoma recovered visual acuity of 6/12 or better. There was no significant difference in the final visual acuity between those patients who had an intraocular lens implanted and those who did not (P=0.18. Univariate analysis was performed for selected risk factors such as age, sex and duration of glaucomatous process as predictors of final visual acuity and odds ratios with 95% confidence intervals were calculated. Patients with age more than 60 years (OR=2.7, 95% CI=1.04 - 6.93 and in whom the glaucoma was present for more than 5 days (OR=3.1, 95% CI=1.21 - 8.13 had a significantly higher risk of poor visual outcome post-operatively.

  9. Nitrous oxide flux following tropical land clearing

    Science.gov (United States)

    Luizao, Flavio; Luizao, Regina; Matson, Pamela; Livingston, Gerald; Vitousek, Peter

    1989-01-01

    The importance of seasonal cycles of N2O flux from tropical ecosystems and the possibility that tropical deforestation could contribute to the ongoing global increase in N2O concentrations were assessed by measuring N2O flux from forest, cleared land, and pasture over an annual cycle in the central Amazon. A pasture that had been converted from tropical forest had threefold greater annual N2O flux than a paired forest site; similar results were obtained in spot measurements in other pastures. If these results are general, such tropical pastures represent a globally significant source of increased N2O.

  10. A gap clearing kicker for Main Injector

    CERN Document Server

    Kourbanis, I; Biggs, J; Brown, B; Capista, D; Jensen, C C; Krafczyk, G E; Morris, D K; Scott, D; Seiya, K; Ward, S R; Wu, G; Yang, M -J

    2012-01-01

    Fermilab Main Injector has been operating at high Beam Power levels since 2008 when multi-batch slip stacking became operational. In order to maintain and increase the beam power levels the localized beam loss due to beam left over in the injection kicker gap during slip stacking needs to be addressed. A set of gap clearing kickers that kick any beam left in the injection gap to the beam abort have been built. The kickers were installed in the summer of 2009 and became operational in November of 2010. The kicker performance and its effect on the beam losses will be described.

  11. Greenhouse problem in the Amazon jungle clearing

    International Nuclear Information System (INIS)

    This paper discusses the contribution of Amazon jungle clearing to the greenhouse problem and makes an assessment of long-run prospects. The introductory sections pose the problem from both international and Brazilian perspectives. The next section describes major features of the Amazonia ecosystems and presents methods and evidence on deforestation and on its impact on carbon dioxide emissions. Based upon cross-section information for a sample of municipalities in the Brazilian Amazon, the following section estimates elasticities of deforestation in relation to major economic factors- government policies included- and uses them to make projections for the future pace of deforestation. The last section discusses policy alternatives to slow down forest conversion

  12. CHINA'S WORST OIL LEAK CLEARED EXPENSIVELY

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Eight days and nights of clean-up efforts after the worst oil leak ever in Chinese waters, the aftermath of a collision between two foreign ships happening at 9:35 pm on December 7 about 8 nautical miles away from the mouth of the Pearl River and near the Danjiang Island, have finally paid off. So far, hundreds of tons of waste oil and polluted water have been cleared up. A large area of oil spills has been cleaned thanks to the prompt and proper operation launched just two hours after the accident.

  13. PLANETARY CHAOTIC ZONE CLEARING: DESTINATIONS AND TIMESCALES

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Sarah; Malhotra, Renu [Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States)

    2015-01-20

    We investigate the orbital evolution of particles in a planet's chaotic zone to determine their final destinations and their timescales of clearing. There are four possible final states of chaotic particles: collision with the planet, collision with the star, escape, or bounded but non-collision orbits. In our investigations, within the framework of the planar circular restricted three body problem for planet-star mass ratio μ in the range 10{sup –9} to 10{sup –1.5}, we find no particles hitting the star. The relative frequencies of escape and collision with the planet are not scale-free, as they depend upon the size of the planet. For planet radius R{sub p} ≥ 0.001 R{sub H} where R{sub H} is the planet's Hill radius, we find that most chaotic zone particles collide with the planet for μ ≲ 10{sup –5}; particle scattering to large distances is significant only for higher mass planets. For fixed ratio R{sub p} /R{sub H} , the particle clearing timescale, T {sub cl}, has a broken power-law dependence on μ. A shallower power law, T {sub cl} ∼ μ{sup –1/3}, prevails at small μ where particles are cleared primarily by collisions with the planet; a steeper power law, T {sub cl} ∼ μ{sup –3/2}, prevails at larger μ where scattering dominates the particle loss. In the limit of vanishing planet radius, we find T {sub cl} ≈ 0.024 μ{sup –3/2}. The interior and exterior boundaries of the annular zone in which chaotic particles are cleared are increasingly asymmetric about the planet's orbit for larger planet masses; the inner boundary coincides well with the classical first order resonance overlap zone, Δa {sub cl,} {sub int} ≅ 1.2 μ{sup 0.28} a{sub p} ; the outer boundary is better described by Δa {sub cl,} {sub ext} ≅ 1.7 μ{sup 0.31} a{sub p} , where a{sub p} is the planet-star separation.

  14. Hospitality as lens for migration studies

    DEFF Research Database (Denmark)

    Greve, Anni

    their duties (welfare ‘parasites’) but even betray the host. Next, an enquiry of the concept of hospitality as possible lens for migration studies; it implies a twofold analyses with two levels, a macro level, to focus our attention to the modalities of hospitality given by the juridical status of the...

  15. The special applications of Tevatron electron lens

    International Nuclear Information System (INIS)

    Besides the Tevatron Electron Lens (TEL) runs as a R and D project for Tevatron Beam-Beam Compensation, it is used daily as a Beam Abort Gap Cleaner for collider operations. It can also be served as beam exciter for beam dynamics measurements and slow proton or antiproton bunch remover. This report describes all these applications and observations

  16. Disruptive advancement in precision lens mounting

    Science.gov (United States)

    Lamontagne, Frédéric; Desnoyers, Nichola; Doucet, Michel; Côté, Patrice; Gauvin, Jonny; Anctil, Geneviève

    2015-09-01

    Threaded rings are used to fix lenses in a large portion of opto-mechanical assemblies. This is the case for the low cost drop-in approach in which the lenses are dropped into cavities cut into a barrel and clamped with threaded rings. The walls of a cavity are generally used to constrain the lateral and axial position of the lens within the cavity. In general, the drop-in approach is low cost but imposes fundamental limitations especially on the optical performances. On the other hand, active alignment methods provide a high level of centering accuracy but increase the cost of the optical assembly. This paper first presents a review of the most common lens mounting techniques used to secure and center lenses in optical systems. Advantages and disadvantages of each mounting technique are discussed in terms of precision and cost. Then, the different contributors which affect the centering of a lens when using the drop-in approach, such as the threaded ring, friction, and manufacturing errors, are detailed. Finally, a patent pending lens mounting technique developed at INO that alleviates the drawbacks of the drop-in and the active alignment approaches is introduced. This innovative auto-centering method requires a very low assembly time, does not need tight manufacturing tolerances and offers a very high level of centering accuracy, usually less than 5 μm. Centering test results performed on real optical assemblies are also presented.

  17. Changes in "thermal lens" measure diffusivity

    Science.gov (United States)

    Gupta, A.; Hong, S. D.; Moacanin, J.

    1980-01-01

    In an extension of "thermal lens" effect to new applications and better resolution, two laser beams combine to rapidly measure thermal diffusivity and other molecular dynamic properties. New double-beam technique handles very small samples unlike classical techniques for measuring diffusivity. It can be used for measurements on samples undergoing stress, making it applicable to data collection for structural engineering.

  18. Contact Lens-Related Eye Infections

    Science.gov (United States)

    ... may lead to the need for a cornea transplant . Learn more about keratitis: Bacterial keratitis Fungal keratitis Herpes keratitis Symptoms of contact lens-related infections may include blurry vision, unusual redness of the eye, pain in the eye, tearing or discharge from ...

  19. Aberrations of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    Czech Academy of Sciences Publication Activity Database

    Konvalina, Ivo; Müllerová, Ilona; Hovorka, Miloš

    Berlin : Springer, 2008 - (Luysberg, M.; Tillmann, K.; Weirich, T.), s. 569-570 ISBN 978-3-540-85154-7. [EMC 2008 - European Microscopy Congress /14./. Aachen (DE), 01.09.2008-05.09.2008] R&D Projects: GA MŠk OE08012; GA AV ČR IAA100650803 Institutional research plan: CEZ:AV0Z20650511 Keywords : cathode lens * aberrations * focus ing lens Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  20. Comparison of Different Presbyopia Treatments: Refractive Lens Exchange with Multifocal Intraocular Lens Implantation Versus LASIK Monovision

    OpenAIRE

    Barišić, Ante; Gabrić, Nikica; Dekaris, Iva; Romac, Ivana; Bohač, Maja; Jurić, Branka

    2010-01-01

    There are several methods for presbyopia treatment. Refractive lens exchange (RLE) followed by multifocal intraocular lens (MFIOL) implantation enables high rate of spectacle independance but have some visual disturbances. Laser in Situ Keratomileusis (LASIK) monovision gives patient ability to have good distant vision with dominant eye and good near vision with nondominant eye. In this prospective randomized study we wanted to compare clinical outcomes in patients who underwent either of the...

  1. Focusing by a high-power, low-Fresnel-number lens: the fly facet lens

    OpenAIRE

    Stavenga, D.G.; Hateren, J.H. van

    1991-01-01

    Diffraction by fly facet lenses has been investigated by photographing the diffraction patterns at various distances from a facet lens whose power was estimated to be 2.03 × 10^4 D. We studied three different aperture diameters with Fresnel numbers of the order of unity. A large focal shift was prominent at the lower Fresnel number. The measured diffraction patterns correspond to those calculated with the Kirchhoff diffraction theory for an aberration-free lens with low Fresnel numbers.

  2. A novel scanning lens instrument for evaluating Fresnel lens performance: equipment development and initial results

    OpenAIRE

    Herrero Martin, Rebeca; Miller, David C.; Kurtz, Sarah R.; Anton Hernandez, Ignacio; Sala Pano, Gabriel

    2013-01-01

    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....

  3. High Dk piggyback contact lens system for contact lens-intolerant keratoconus patients

    OpenAIRE

    Tomris Sengor; Sevda Aydin Kurna; Suat Aki; et al

    2011-01-01

    Tomris Sengor, Sevda Aydin Kurna, Suat Aki, Yelda ÖzkurtFatih Sultan Mehmet Training and Research Hospital, Istanbul, TurkeyBackground: The aim of the study was to examine the clinical success of high Dk (oxygen permeability) piggyback contact lens (PBCL) systems for the correction of contact lens intolerant keratoconus patients.Methods: Sixteen patients (29 eyes) who were not able to wear gas-permeable rigid lenses were included in this study. Hyper Dk silicone hydrogel (oxygen tran...

  4. The influence of lens material and lens wear on the removal and viability of staphylococcus epidermidis

    OpenAIRE

    Santos, Lívia; Rodrigues, Diana Alexandra Ferreira; Lira, Madalena; Oliveira, M. Elisabete; Oliveira, Rosário; Yebra-Pimentel Vilar, Eva; Azeredo, Joana

    2008-01-01

    Purpose: The aim of this study was to evaluate the influence of lens material and lens wear on the removal capability of Staphylococcus epidermidis. Assessment of viability of remaining adhered bacteria was another goal of this work. Four silicone hydrogel materials (galyfilcon A, balafilcon A, lotrafilcon A, lotrafilcon B) and one conventional hydrogel material (etafilcon A) were assayed. Methods: Detachment studies on S. epidermidis were carried out in a parallel plate flow chamber...

  5. Planetary chaotic zone clearing: destinations and timescales

    CERN Document Server

    Morrison, Sarah

    2014-01-01

    We investigate the orbital evolution of particles in a planet's chaotic zone to determine their final destinations and their timescales of clearing. There are four possible final states of chaotic particles: collision with the planet, collision with the star, escape, or bounded but non-collision orbits. In our investigations, within the framework of the planar circular restricted three body problem for planet-star mass ratio $\\mu$ in the range $10^{-9}$ to $10^{-1.5}$, we find no particles hitting the star. The relative frequencies of escape and collision with the planet are not scale-free, as they depend upon the size of the planet. For planet radius $R_p\\ge0.001R_H$ where $R_H$ is the planet's Hill radius, we find that most chaotic zone particles collide with the planet for $\\mu\\lesssim10^{-5}$; particle scattering to large distances is significant only for higher mass planets. For fixed ratio $R_p/R_H$, the particle clearing timescale, $T_{cl}$, has a broken power-law dependence on $\\mu$. A shallower power...

  6. Multi-actuator adaptive lens for wavefront correction in optical coherence tomography and two-photon excitation fluorescence microscopy (Conference Presentation)

    Science.gov (United States)

    Bonora, Stefano; Lee, Sujin; Jian, Yifan; Cua, Michelle; Pugh, Edward N.; Zawadzki, Robert J.; Sarunic, Marinko V.

    2016-03-01

    We present a new type of adaptive lens with 18 actuators that can correct up the 4th order of aberration. The Multi-actuator Adaptive Lens (M-AL) can guarantee a good level of aberration correction for many applications and, with respect to deformable mirror, it allows the realization of more compact and simple optical systems. The adaptive lens is based on the use of piezoelectric actuators and, without any obstruction or electrodes in the clear aperture, can guarantee a fast response time, in the order of about 10ms. The clear aperture of the M-AL allows its use in "classical" Adaptive Optics configuration together with a wavefront sensor. To introduce a further simplification to the optical system design we show that the adaptive lens can be also driven with a wavefront sensorless control algorithm during in vivo optical coherence tomography of the human retina and for two-photon excitation fluorescence microscopy. In the experimental setup we used two aberration correcting devices a commercial adaptive lens (AL) with a high dynamic range to correct for defocus and the Multi-actuator Adaptive Lens (M-AL) to correct for the Zernike aberrations up to the 4th order. Experimental results show that the ocular aberrations of human eyes can be successfully corrected with our M-AL for pupils of 5mm and that retinal cones can be readily imaged.

  7. Zoom lens design for tilted objects

    Science.gov (United States)

    Malone, Robert M.; Frayer, Daniel K.; Kaufman, Morris I.; Leffler, Heather R.; McGillivray, Kevin D.; Meidinger, Alfred; Phillips, David H.

    2015-09-01

    When a zoom lens views a tilted finite conjugate object, its image plane is both tilted and distorted depending on magnification. Our camera image plane moves with six degrees of freedom; only one moving doublet lens is required to change magnification. Two lens design models were analyzed. The first required the optical and mechanical axes to be collinear, resulting in a tilted stop. The second allowed the optical axis to be tilted from the lens mechanical axis with an untilted stop moving along the mechanical axis. Both designs produced useful zoom lenses with excellent resolution for a distorted image. For both lens designs, the stop is anchored to the moving doublet and its diameter is unchanged throughout magnification changes. This unusual outcome allows the light level at each camera pixel to remain constant, independent of magnification. As-built tolerance analysis is used to compare both optical models. The design application is for proton radiography. At the end of an accelerator, protons exit an aluminum vacuum window producing a shadowgraph image onto an LYSO (lutetium yttrium orthosilicate) scintillator. The 5″ square scintillator emission reflects off a pellicle and is collected by the zoom lenses located 24″ away. Four zoom lenses will view the same pellicle at different alpha and beta angles. Blue emission from the scintillator is viewed at an alpha angle of -14° or -23° and beta angles of ±9° or ±25°. The pellicle directs the light backwards to a zone where adequate shielding of the cameras can be achieved against radiation scattered from the aluminum window.

  8. Preventive role of lens antioxidant defense mechanism against riboflavin-mediated sunlight damaging of lens crystallins.

    Science.gov (United States)

    Anbaraki, Afrooz; Khoshaman, Kazem; Ghasemi, Younes; Yousefi, Reza

    2016-10-01

    The main components of sunlight reaching the eye lens are UVA and visible light exerting their photo-damaging effects indirectly by the aid of endogenous photosensitizer molecules such as riboflavin (RF). In this study, lens proteins solutions were incubated with RF and exposed to the sunlight. Then, gel mobility shift analysis and different spectroscopic assessments were applied to examine the structural damaging effects of solar radiation on these proteins. Exposure of lens proteins to direct sunlight, in the presence of RF, leads to marked structural crosslinking, oligomerization and proteolytic instability. These structural damages were also accompanied with reduction in the emission fluorescence of Trp and Tyr and appearance of a new absorption peak between 300 and 400nm which can be related to formation of new chromophores. Also, photo-oxidation of lens crystallins increases their oligomeric size distribution as examined by dynamic light scattering analysis. The above mentioned structural insults, as potential sources of sunlight-induced senile cataract and blindness, were significantly attenuated in the presence of ascorbic acid and glutathione which are two important components of lens antioxidant defense system. Therefore, the powerful antioxidant defense mechanism of eye lens is an important barrier against molecular photo-damaging effects of solar radiations during the life span. PMID:27316765

  9. Astigmatic Outcomes of Temporal versus Nasal Clear Corneal Phacoemulsification

    Directory of Open Access Journals (Sweden)

    Mohammad Pakravan

    2009-04-01

    Full Text Available

    PURPOSE: To compare the astigmatic outcomes of phacoemulsification cataract surgery using temporal versus nasal clear corneal incisions. METHODS: In a clinical trial, consecutive patients with senile cataracts underwent phacoemulsification and implantation of a hydrophobic acrylic foldable intraocular lens through a horizontal clear corneal incision (temporal in right and nasal in left eyes. Outcome measures included keratometric astigmatism and surgically induced astigmatism (SIA calculated by the vector analysis method using the Holladay-Cravy-Koch formula. RESULTS: The nasal and temporal groups consisted of 20 eyes each. Mean preoperative keratometric astigmatism was 0.63±0.48 D and 0.38±0.39 D in the temporal and nasal incision groups respectively (P=0.09. Data on 10 eyes in each study group was available for the six-month analysis. Mean keratometric astigmatism was as follows in the temporal and nasal groups respectively: 0.85±0.47 D versus 1.95±0.45 D at 1 week (P < 0.001, 0.73±0.46 D versus 1.79±0.55 D at 4 weeks (P < 0.001, and 0.63±0.30 D versus 1.05±0.56 D at 6 months (P=0.053 after surgery. SIA at the same follow-up intervals was 0.71±0.20 D versus 1.80±0.22 D (P < 0.001, 0.63±0.20 D versus 1.65±0.31 D (P < 0.001 and 0.26±0.46 D versus 0.92±0.36 D (P=0.002 in the temporal versus nasal incision groups

  10. Gram negative bacteria and contact lens induced acute red eye

    Directory of Open Access Journals (Sweden)

    Sankaridurg Padmaja

    1996-01-01

    Full Text Available Two patients using hydrogel contact lenses on a daily wear schedule slept overnight with the lenses and woke up with a Contact Lens Induced Acute Red Eye (CLARE. The contact lenses recovered aseptically at the time of the event grew significant colonies of Pseudomonas aeruginosa and Aeromonas hydrophila in patient A and Pseudomonas aeruginosa and Serratia liquefaciens from patient B. Similar organisams from the contact lenses were recovered from the lens case and lens care solutions of patient B. In both the patients the condition resolved on discontinuation of lens wear. Patient compliance as a requirement for successful contact lens wear is highlighted with the illustration of these cases.

  11. The Protease Ste24 Clears Clogged Translocons.

    Science.gov (United States)

    Ast, Tslil; Michaelis, Susan; Schuldiner, Maya

    2016-01-14

    Translocation into the endoplasmic reticulum (ER) is the first step in the biogenesis of thousands of eukaryotic endomembrane proteins. Although functional ER translocation has been avidly studied, little is known about the quality control mechanisms that resolve faulty translocational states. One such faulty state is translocon clogging, in which the substrate fails to properly translocate and obstructs the translocon pore. To shed light on the machinery required to resolve clogging, we carried out a systematic screen in Saccharomyces cerevisiae that highlighted a role for the ER metalloprotease Ste24. We could demonstrate that Ste24 approaches the translocon upon clogging, and it interacts with and generates cleavage fragments of the clogged protein. Importantly, these functions are conserved in the human homolog, ZMPSTE24, although disease-associated mutant forms of ZMPSTE24 fail to clear the translocon. These results shed light on a new and critical task of Ste24, which safeguards the essential process of translocation. PMID:26771486

  12. 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.

  13. 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

  14. An Electromagnetic Sensor with a Metamaterial Lens for Nondestructive Evaluation of Composite Materials

    Directory of Open Access Journals (Sweden)

    Adriana Savin

    2015-07-01

    Full Text Available This paper proposes the study and implementation of a sensor with a metamaterial (MM lens in electromagnetic nondestructive evaluation (eNDE. Thus, the use of a new type of MM, named Conical Swiss Rolls (CSR has been proposed. These structures can serve as electromagnetic flux concentrators in the radiofrequency range. As a direct application, plates of composite materials with carbon fibers woven as reinforcement and polyphenylene sulphide as matrix with delaminations due to low energy impacts were examined. The evaluation method is based on the appearance of evanescent modes in the space between carbon fibers when the sample is excited with a transversal magnetic along z axis (TMz polarized electromagnetic field. The MM lens allows the transmission and intensification of evanescent waves. The characteristics of carbon fibers woven structure became visible and delaminations are clearly emphasized. The flaws can be localized with spatial resolution better than λ/2000.

  15. Spontaneous late in-the-bag intraocular lens dislocation after can-opener capsulotomy: case report Deslocamento espontâneo e tardio de lente intra-ocular "in-the-bag" após capsulotomia tipo abridor de latas: relato de caso

    OpenAIRE

    Roberto Pinto Coelho; Maria Cristina Zanatto; Jayter Silva Paula; Erasmo Romão

    2005-01-01

    We report a case of a 58-year-old man presenting with a spontaneous and late in-the-bag intraocular lens dislocation to the vitreous. A previous uneventful extracapsular cataract extraction with can-opener style capsulotomy and implantation of a polymethylmethacrylate three-piece lens was performed and, two years after the surgery, the patient developed capsule contraction syndrome with a fibrotic ring formation and dislocation of the intraocular lens. Although uncommon and related mainly to ...

  16. Dispersion tuning with a varifocal diffractive-refractive hybrid lens.

    Science.gov (United States)

    Harm, Walter; Roider, Clemens; Jesacher, Alexander; Bernet, Stefan; Ritsch-Marte, Monika

    2014-03-10

    We present a hybrid diffractive-refractive optical lens doublet consisting of a varifocal Moiré Fresnel lens and a polymer lens of tunable refractive power. The wide range of focal tunability of each lens and the opposite dispersive characteristics of the diffractive and the refractive element are exploited to obtain an optical system where both the Abbe number and the refractive power can be changed separately. We investigate the performance of the proposed hybrid lens at zero overall refractive power by tuning the Abbe number of a complementary standard lens while maintaining a constant overall focal length for the central wavelength. As an application example, the hybrid lens is used to tune to an optimal operating regime for quantitative phase microscopy based on a two-color transport of intensity (TIE) approach which utilizes chromatic aberrations rather than intensity recordings at several planes to reconstruct the optical path length of a phase object. PMID:24663866

  17. The design and fabrication of common optical components lithography lens

    Science.gov (United States)

    Huang, Jiun-Woei

    2015-07-01

    The design and fabrication of common optical components lithography Lens has been carried out for a 1 to 1 stepper. The specification of lens is fulfilled the 3-D lithography system as 2 micron in resolution for 1 inch x 2.8 inches system. The lens has been sophistically designed by dual path in a triplet to reduce the number of components. A single aspherical surface has been applied to reduce the aberration to diffraction limit in lens. The well-made shapes of lens have been suggested. Then, the fabrication of lens has been in the process. Finally, the optical axis of tolerance optical mechanical mountings for lens system in assembly has been analyzed, and valuable for assembly and fabrication.

  18. Extracapsular cataract extraction compared with small incision surgery by phacoemulsification: a randomised trial

    OpenAIRE

    Minassian, D.; Rosen, P.; DART, J; Reidy, A.; Desai, P; Sidhu, M

    2001-01-01

    BACKGROUND—Cataract extraction constitutes the largest surgical workload in ophthalmic units throughout the world. Extracapsular cataract extraction (ECCE), through a large incision, with insertion of an intraocular lens has been the most widely used method from 1982 until recently. Technological advances have led to the increasing use of phacoemulsification (Phako) to emulsify and remove the lens The technique requires a smaller incision, but requires substantial capital investment in theatr...

  19. Hyaluronic acid production and hyaluronidase activity in the newt iris during lens regeneration

    International Nuclear Information System (INIS)

    The process of lens regeneration in newts involves the dedifferentiation of pigmented iris epithelial cells and their subsequent conversion into lens fibers. In vivo this cell-type conversion is restricted to the dorsal region of the iris. We have examined the patterns of hyaluronate accumulation and endogenous hyaluronidase activity in the newt iris during the course of lens regeneration in vivo. Accumulation of newly synthesized hyaluronate was estimated from the uptake of [3H]glucosamine into cetylpyridinium chloride-precipitable material that was sensitive to Streptomyces hyaluronidase. Endogenous hyaluronidase activity was determined from the quantity of reducing N-acetylhexosamine released upon incubation of iris tissue extract with exogenous hyaluronate substrate. We found that incorporation of label into hyaluronate was consistently higher in the regeneration-activated irises of lentectomized eyes than in control irises from sham-operated eyes. Hyaluronate labeling was higher in the dorsal (lens-forming) region of the iris than in ventral (non-lens-forming) iris tissue during the regeneration process. Label accumulation into hyaluronate was maximum between 10 and 15 days after lentectomy, the period of most pronounced dedifferentiation in the dorsal iris epithelium. Both normal and regenerating irises demonstrated a high level of endogenous hyaluronidase activity with a pH optimum of 3.5-4.0. Hyaluronidase activity was 1.7 to 2 times higher in dorsal iris tissue than in ventral irises both prior to lentectomy and throughout the regeneration process. We suggest that enhanced hyaluronate accumulation may facilitate the dedifferentiation of iris epithelial cells in the dorsal iris and prevent precocious withdrawal from the cell cycle. The high level of hyaluronidase activity in the dorsal iris may promote the turnover and remodeling of extracellular matrix components required for cell-type conversion

  20. Hyaluronic acid production and hyaluronidase activity in the newt iris during lens regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kulyk, W.M.; Zalik, S.E.; Dimitrov, E.

    1987-09-01

    The process of lens regeneration in newts involves the dedifferentiation of pigmented iris epithelial cells and their subsequent conversion into lens fibers. In vivo this cell-type conversion is restricted to the dorsal region of the iris. We have examined the patterns of hyaluronate accumulation and endogenous hyaluronidase activity in the newt iris during the course of lens regeneration in vivo. Accumulation of newly synthesized hyaluronate was estimated from the uptake of (/sup 3/H)glucosamine into cetylpyridinium chloride-precipitable material that was sensitive to Streptomyces hyaluronidase. Endogenous hyaluronidase activity was determined from the quantity of reducing N-acetylhexosamine released upon incubation of iris tissue extract with exogenous hyaluronate substrate. We found that incorporation of label into hyaluronate was consistently higher in the regeneration-activated irises of lentectomized eyes than in control irises from sham-operated eyes. Hyaluronate labeling was higher in the dorsal (lens-forming) region of the iris than in ventral (non-lens-forming) iris tissue during the regeneration process. Label accumulation into hyaluronate was maximum between 10 and 15 days after lentectomy, the period of most pronounced dedifferentiation in the dorsal iris epithelium. Both normal and regenerating irises demonstrated a high level of endogenous hyaluronidase activity with a pH optimum of 3.5-4.0. Hyaluronidase activity was 1.7 to 2 times higher in dorsal iris tissue than in ventral irises both prior to lentectomy and throughout the regeneration process. We suggest that enhanced hyaluronate accumulation may facilitate the dedifferentiation of iris epithelial cells in the dorsal iris and prevent precocious withdrawal from the cell cycle. The high level of hyaluronidase activity in the dorsal iris may promote the turnover and remodeling of extracellular matrix components required for cell-type conversion.

  1. Experimental studies on ion diodes and theoretical studies on ion beam focusing by magnetic lens

    International Nuclear Information System (INIS)

    Experimental investigation of factors that determine the optimum performance of magnetically insulated ion diodes for light ion inertial confinement fusion (ICF) indicates that degradation of both ion production efficiency and beam divergence occurs when current densities of above about 1.5 kA/cm2 are extracted from passive flashover ion sources on the 1 MV, 4 Ω, 40 ns LION accelerator. Observations of these phenomena are complicated by ablation effects on ion diagnostics at high beam fluences. Theoretical studies of ion beam propagation through plasma filled magnetic lens focusing systems for ICF show that the plasma response is in a whistler wave dominated regime. Criteria are developed for lens and plasma parameters that allow self-field perturbations of the beam to be small enough for good beam transport to an ICF target. (author). 3 figs

  2. Design of object surveillance system based on enhanced fish-eye lens

    Institute of Scientific and Technical Information of China (English)

    Jianhui Wu; Kuntao Yang; Qiaolian Xiang; Nanyang Zhang

    2009-01-01

    A new method is proposed for the object surveillance system based on the enhanced fish-eye lens and the high speed digital signal processor (DSP). The improved fish-eye lens images an ellipse picture on the charge-coupled device (CCD) surface, which increases both the utilization rate of the 4:3 rectangular CCD and the imaging resolution, and remains the view angle of 183°. The algorithm of auto-adapted renewal background subtraction (ARBS) is also explored to extract the object from the monitoring image. The experimental result shows that the ARBS algorithm has high anti-jamming ability and high resolution, leading to excellent object detecting ability from the enhanced elliptical fish-eye image under varies en-vironments. This system has potential applications in different security monitoring fields due to its wide monitoring space, simple structure, working stability, and reliability.

  3. Anterior segment and retinal OCT imaging with simplified sample arm using focus tunable lens technology (Conference Presentation)

    Science.gov (United States)

    Grulkowski, Ireneusz; Karnowski, Karol; Ruminski, Daniel; Wojtkowski, Maciej

    2016-03-01

    Availability of the long-depth-range OCT systems enables comprehensive structural imaging of the eye and extraction of biometric parameters characterizing the entire eye. Several approaches have been developed to perform OCT imaging with extended depth ranges. In particular, current SS-OCT technology seems to be suited to visualize both anterior and posterior eye in a single measurement. The aim of this study is to demonstrate integrated anterior segment and retinal SS-OCT imaging using a single instrument, in which the sample arm is equipped with the electrically tunable lens (ETL). ETL is composed of the optical liquid confined in the space by an elastic polymer membrane. The shape of the membrane, electrically controlled by a specific ring, defines the radius of curvature of the lens surface, thus it regulates the power of the lens. ETL can be also equipped with additional offset lens to adjust the tuning range of the optical power. We characterize the operation of the tunable lens using wavefront sensing. We develop the optimized optical set-up with two adaptive operational states of the ETL in order to focus the light either on the retina or on the anterior segment of the eye. We test the performance of the set-up by utilizing whole eye phantom as the object. Finally, we perform human eye in vivo imaging using the SS-OCT instrument with versatile imaging functionality that accounts for the optics of the eye and enables dynamic control of the optical beam focus.

  4. Understanding Science Through the Computational Lens

    Institute of Scientific and Technical Information of China (English)

    Richard M. Karp

    2011-01-01

    This article explores the changing nature of the interaction between computer science and the natural and social sciences.After briefly tracing the history of scientific computation,the article presents the concept of computational lens,a metaphor for a new relationship that is emerging between the world of computation and the world of the sciences.Our main thesis is that,in many scientific fields,the processes being studied can be viewed as computational in nature,in the sense that the processes perform dynamic transformations on information represented as digital data.Viewing natural or engineered systems through the lens of their computational requirements or capabilities provides new insights and ways of thinking.A number of examples are discussed in support of this thesis.The examples are from various fields,including quantum computing,statistical physics,the World Wide Web and the Internet,mathematics,and computational molecular biology.

  5. Free volume in contact lens polymers

    Science.gov (United States)

    Singh, Jag J.; Eftekhari, Abe; Upchurch, Billy T.; Burns, Karen S.

    1990-01-01

    We have measured the free volume and gas permeability in several contact lens specimens as part of a Space Commercialization Program. Free volume was measured using positron lifetime spectroscopy, while permeability for O2, N2, and CO2 gases was measured using mass spectrometry and polarography. It has been noted that permeability for all gases increases with the mean free volume cell size in the test samples. As might be expected, the specimens with the highest free volume fraction also exhibit the lowest Rockwell Hardness Number. An interesting corollary of this study is the finding that the presence of fluorine atoms in the lens chemical structure inhibits filling up of their free volume cells. This is expected to allow the lenses to breathe freely while in actual use.

  6. 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.

  7. Aerogel detector with a Fresnel lens focalization

    International Nuclear Information System (INIS)

    The use of threshold Cherenkov detectors for the identification of high momentum particles in high energy physics experiments is connected with the efficiency of detection of light in the aerogel. As one goes lower in the refractive index, less photons are emitted, and more attention should be paid to the improvements of the detection efficiency. The light integration box method relies on photomultipliers of large size and requires even two of them. We have studied the possibility to use a thin focalizing element (Fresnel lens) between the aerogel and the photomultiplier to focalize the light onto a smaller diameter photomultiplier. The results show that for good aerogel and low indices of refraction (<1.01) the scheme with the aerogel and the Fresnel lens may be superior and less costly than the conventional set-up.

  8. Nuclear threat. A clear and present danger

    International Nuclear Information System (INIS)

    It was disappointed at the discussion in the review conference of the NPT held in 2005. The fact may be caused by the estrangement between the international urgent issues related to the non-proliferation and the effectiveness of archaic measures through the NPT. However, it should not be recognized that the international obligation and worth of NPT has been gone. The NPT referred the typical international situation under the cold war era. Although several permanent issues of the nuclear non-proliferation exist in current discussions, the activities relevant to the NPT may not be effect against newly unstable situations after the September 11th of 2001. Urgent challenges to be taken are that we must strictly analyze the interventions between 'the clear and present danger' of our world and the nuclear herms, and must take appropriate actions toward them without influences from previous international situations that might be subsisted in current international treaties and agreements. This paper identified the features of nuclear threats based on the four categories and examined the possibilities of nuclear terrorism from previous facts with the inductive inference. The results identified the possibility of nuclear facility attack and of radioactive materials theft by the Polico-Religious Groups and others are stood out. The authors would suggest the important of urgent recognition to establish the certain security system against nuclear terrorism. (author)

  9. Rose-K contact lens for keratoconus

    Directory of Open Access Journals (Sweden)

    Jain Arun

    2007-01-01

    Full Text Available Aim: To report clinical experience and the comparative value of axial and instantaneous topography data in fitting Rose-K design contact lenses in moderate and severe keratoconus. Materials and Methods: Thirty-eight eyes (of 23 patients with keratoconus were fitted with Rose-K design contact lenses and followed up for at least six months or more. Visual acuity with habitual vision correction available was measured. Axial and instantaneous topography maps for each eye were recorded. Contact lens wear comfort was graded on a ten point rating scale every three months. Results: Fourteen (100% moderate keratoconus eyes (average Sim K 48.61 ± 1.24D and 23 of 24 (96% of severe keratoconus eyes (average Sim K 60.88 ± 5.31D were successfully fitted with the Rose-K lenses. Final fit contact lenses in severe keratoconus had statistically significant steeper base curves compared to average axial corneal curvature than in moderate keratoconus eyes. Average simulated corneal curvature on axial maps predicted final fit contact lens base curves significantly better than on instantaneous maps. Thirty-three of the 37 eyes fitted with contact lenses maintained wear comfort over average follow up period of 13 ± 3.5 months. Conclusions: Rose-K design rigid contact lenses are successful in visually rehabilitating 100% of moderate and 96% of severe keratoconus eyes. Most patients (90% maintained contact lens wear comfort. Corneal curvature on axial maps is a better predictive of base curve of final fit contact lens.

  10. Singlet vector models on lens spaces

    International Nuclear Information System (INIS)

    We present exact computations of partition functions of singlet vector models (infinite level Chern-Simons-matter theories) on lens spaces L(p,1). We identify light topological configurations and their spectra, and we comment on the relevance of our results in studying both the UV completions of Vasiliev’s higher-spin theories and the dS/CFT correspondence in the large N limit

  11. The Frontier Fields Lens Modeling Comparison Project

    OpenAIRE

    Meneghetti, M.; Natarajan, P.; Coe, D.; Contini, E.; De Lucia, G.; Giocoli, C.; Acebron, A.; S. Borgani(INFN - Trieste, c/o Dipartimento di Astronomia, Univ. di Trieste, Italy); Bradac, M.; Diego, J. M.; Hoag, A.; Ishigaki, M.; Johnson, T. L.; Jullo, E; Kawamata, R

    2016-01-01

    Gravitational lensing by clusters of galaxies offers a powerful probe of their structure and mass distribution. Deriving a lens magnification map for a galaxy cluster is a classic inversion problem and many methods have been developed over the past two decades to solve it. Several research groups have developed techniques independently to map the predominantly dark matter distribution in cluster lenses. While these methods have all provided remarkably high precision mass maps, particularly wi...

  12. Magnetic Resonance Imaging with a Dielectric Lens

    OpenAIRE

    Vazquez, F.; Marrufo, O.; MARTIN,R; Rodriguez, A. O.

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circula...

  13. Ulcerative keratitis associated with contact lens wear

    OpenAIRE

    Bharathi M; Ramakrishnan R; Meenakshi R; Kumar C; Padmavathy S.; Mittal S

    2007-01-01

    To review the microbiological profile of ulcerative keratitis associated with contact lens (CL)-wear, 35 patients with culture-proven CL-associated microbial keratitis were studied between September 1999 and September 2002. Corneal scrapes and CL-care products were collected and were subjected to microbiological evaluation. Gram-negative bacilli alone were recovered from the corneal scrapes of all 35 (100%) patients, all 70 (100%) CL storage case wells and also from CL-care solu...

  14. Microstructure of Lentil Seeds (Lens Culinaris)

    OpenAIRE

    Hughes, Joe S.; Swanson, Barry G.

    1986-01-01

    Scanning electron microscopy (SEM) was used to investigate the microstructure of five cultivars of lentil seeds (Lens culinaris). Lentil cot yledons contain sphericai starch granules surrounded by protein bodies similar to starch granules and protein bodies observed in cotyledons of other food legumes. Examination of the lentil seed coat in cross - section revealed outer palisade and inner parenchyma layers characteris tic of legumes. The subepidermal layer, however, is comprised of hourglass...

  15. Sustained drug released from contact lens

    OpenAIRE

    Ferreira, J. A.; De Oliveira, P.; Silva, P.M. da; Carreira, A; Gil, H; Murta, J. N.

    2009-01-01

    This paper focuses on ophthalmic drug release from a loaded copolymer: the drug is dispersed in the polymeric matrix and entrapped in particles. The copolymer is based in 2-hydroxyethyl methacrylate co-methacrylic acid and silicone is used to prepare the loaded particles. A mathematical model to simulate the drug release is proposed and a qualitative analysis is performed. Experimental results are compared with simulation results. Contact lens made from the presented copolymer ...

  16. Nanoindentation of soft contact lens materials

    OpenAIRE

    Selby, Alastair Phillip

    2012-01-01

    The launch of silicone hydrogel contact lenses has led to a rise in the incidence of mechanically-related clinical complications, which is thought to be due to the increased stiffness of these materials compared to conventional hydrogel lens materials. The mechanical characteristics of hydrogel contact lenses have traditionally been investigated using tensile testing which investigated the bulk material characteristics. This thesis presents a study intended to establish a repeatable method fo...

  17. A stereoscopic lens for digital cinema cameras

    Science.gov (United States)

    Lipton, Lenny; Rupkalvis, John

    2015-03-01

    Live-action stereoscopic feature films are, for the most part, produced using a costly post-production process to convert planar cinematography into stereo-pair images and are only occasionally shot stereoscopically using bulky dual-cameras that are adaptations of the Ramsdell rig. The stereoscopic lens design described here might very well encourage more live-action image capture because it uses standard digital cinema cameras and workflow to save time and money.

  18. Comparison and Calibration of Mobile Phone Fisheye Lens and Regular Fisheye Lens via Equidistant Model

    Directory of Open Access Journals (Sweden)

    Cumhur Sahin

    2016-01-01

    Full Text Available Nowadays, mobile phones are more than a device that can only satisfy the communication need between people. In addition to providing ease to human lives with various applications, lens kits that can be integrated to mobile phones have recently been introduced. Fisheye lenses that are compliant with mobile phones are one of these new types of equipment. Since fisheye lenses integrated with mobile phones are lightweight and easy to use, they are advantageous. In addition to this advantage, whether fisheye lens and mobile phone combination can be used in a photogrammetric way is experimented, and if so, what will be the result. The main purpose of this study is to test fisheye lens equipment used with mobile phones. In this study, standard calibration of “Olloclip 3 in one” fisheye lens used with iPhone 4S mobile phone and “Nikon FC-E9” fisheye lens used with Nikon Coolpix8700 are compared based on equidistant model. The results of these calibrations are analyzed, using photogrammetric bundle block adjustment. This study suggests a precalibration process of these kinds of hardware for the photogrammetric process in the test field.

  19. Pitfalls in aphakic contact lens fitting

    Directory of Open Access Journals (Sweden)

    Dada Vijay

    1990-01-01

    Full Text Available We examined 23 consecutive cases of unilateral aphakia reporting to the contact lens office for endothelial count and morphology, corneal thickness and toricity. The fellow eye served as a control in all the cases. It was found that there is a significant drop in the central endothelial cell density, and change in the size and shape of the cells. These observations indicate a thermodynamically unstable state. The aphakic corneas were thicker than the controls but not to a significant extent. The cell count and pachymetry had no statistical correlation. Toricity of the aphakic corneas make successful fitting of a lens difficult. Since prolonged use of extended wear gas permeable as well as hydrogel lenses have a deleterious effect on the endothelium it is suggested that a careful case selection be made and strict monitoting carried out at follow up. These corneas are liable for decompensation with only mild noxious stimuli. This article is intended to acquaint the ophthalmologist with the pitfalls in aphakic contact lens fitting so that a cautious follow up may be planned.

  20. Human lens colouration, age and cataract

    International Nuclear Information System (INIS)

    Full text: The human lens biosynthesises UV filter compounds which effectively remove light in the 300-400nm band. These chemicals are present either as an aid to visual acuity, or to filter out damaging UV radiation. The primate UV filters are 3-hydroxykynurenine analogues derived from the metabolism of tryptophan. We have recently demonstrated that these endogenous UV filters are not innocuous, but are in fact capable of binding to proteins, including the crystalline proteins which make up the bulk of the lens. Thus, over time, the levels of protein - bound UV filters increase and this results in the human lens becoming progressively more yellow as we age. This colouration affects our colour vision and it may also be responsible for the brown colour of lenses which is the hallmark of age-related nuclear cataract. An understanding of the intrinsic instability of the endogenous UV filters, combined with changes in the internal transport of these and other small molecular weight compounds including antioxidants, such as glutathione, is allowing us to gain an insight into the processes responsible for the development of age-related cataract: the major cause of world blindness

  1. Thin wetting film lens-less imaging

    International Nuclear Information System (INIS)

    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 mm2 to 12 mm2 to 24 mm2, which allows the detection of bacteria contained in 0.5 μl to 4 μl to 10 μl, respectively. (authors)

  2. Radiation dose to the lens and cataract formation

    International Nuclear Information System (INIS)

    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

  3. Clear cell renal cell tumors: Not all that is "clear" is cancer.

    Science.gov (United States)

    Williamson, Sean R; Cheng, Liang

    2016-07-01

    Continued improvement of our understanding of the clinical, histologic, and genetic features of renal cell tumors has progressively evolved renal tumor classification, revealing an expanding array of distinct tumor types with different implications for prognosis, patient counseling, and treatment. Although clear cell renal cell carcinoma is unequivocally the most common adult renal tumor, there is growing evidence that some "clear cell" renal neoplasms, such as exemplified by multilocular cystic clear cell renal neoplasm of low malignant potential (formerly multilocular cystic renal cell carcinoma), do not have the same potential for insidious progression and metastasis, warranting reclassification as low malignant potential tumors or benign neoplasms. Still other novel tumor types such as clear cell papillary renal cell carcinoma have been more recently recognized, which similarly have shown a conspicuous absence of aggressive behavior to date, suggesting that these too may be recategorized as noncancerous or may be premalignant neoplasms. This importance for prognosis is increasingly significant in the modern era, in which renal masses are increasingly found incidentally by imaging techniques at a small tumor size, raising consideration for less aggressive management options guided by renal mass biopsy diagnosis, including imaging surveillance, tumor ablation, or partial nephrectomy. PMID:26988177

  4. When a Cleared Rape Is Not Cleared: A Multilevel Study of Arrest and Exceptional Clearance.

    Science.gov (United States)

    Walfield, Scott M

    2016-05-01

    As rape remains one of the most underreported and least likely to be cleared of the violent crimes, it is of paramount importance to understand the factors associated with the likelihood of a case being cleared by law enforcement. This study uses data from the National Incident-Based Reporting System (NIBRS) and the Law Enforcement Management and Administrative Statistics (LEMAS), and a multilevel modeling approach to examine the relationship between victim, offender, incident, and police department characteristics contrasting the two types of clearance: arrest and exceptional clearance. The latter occurs due to reasons outside of law enforcement's control and despite being considered cleared, the offender is not arrested, charged, nor turned over for prosecution. Of the 16,231 cleared rapes in 238 departments, nearly half (47%) results in exceptional clearance when the victim refuses to cooperate or when prosecution is declined. Incident-level variables have a greater effect on the likelihood of exceptional clearance than victim and offender variables. The department explained a nontrivial amount of variation in the dependent variable, as 37% of the variance in type of clearance was between-department variation. Implications for future research on exceptional clearance and NIBRS are discussed. PMID:25646164

  5. 76 FR 45730 - Customer Clearing Documentation and Timing of Acceptance for Clearing

    Science.gov (United States)

    2011-08-01

    ... derivatives clearing organization (DCO) level.\\4\\ \\4\\ See, e.g., 76 FR 3698 (Jan. 20, 2011) (Risk Management... permitting them to do so. \\5\\ 75 FR 70152 (Nov. 17, 2010) (Implementation of Conflicts of Interest Policies and Procedures by Futures Commission Merchants and Introducing Brokers); 75 FR 71391 (Nov. 23,...

  6. MODIS Collection 6 Clear Sky Restoral (CSR): Filtering Cloud Mast 'Not Clear' Pixels

    Science.gov (United States)

    Meyer, Kerry G.; Platnick, Steven Edward; Wind, Galina; Riedi, Jerome

    2014-01-01

    Correctly identifying cloudy pixels appropriate for the MOD06 cloud optical and microphysical property retrievals is accomplished in large part using results from the MOD35 1km cloud mask tests (note there are also two 250m subpixel cloud mask tests that can convert the 1km cloudy designations to clear sky). However, because MOD35 is by design clear sky conservative (i.e., it identifies "not clear" pixels), certain situations exist in which pixels identified by MOD35 as "cloudy" are nevertheless likely to be poor retrieval candidates. For instance, near the edge of clouds or within broken cloud fields, a given 1km MODIS field of view (FOV) may in fact only be partially cloudy. This can be problematic for the MOD06 retrievals because in these cases the assumptions of a completely overcast homogenous cloudy FOV and 1-dimensional plane-parallel radiative transfer no longer hold, and subsequent retrievals will be of low confidence. Furthermore, some pixels may be identified by MOD35 as "cloudy" for reasons other than the presence of clouds, such as scenes with thick smoke or lofted dust, and should therefore not be retrieved as clouds. With such situations in mind, a Clear Sky Restoral (CSR) algorithm was introduced in C5 that attempts to identify pixels expected to be poor retrieval candidates. Table 1 provides SDS locations for CSR and partly cloudy (PCL) pixels.

  7. 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.

  8. FEM simulation of the human lens compared to ex vivo porcine lens cutting pattern: a possible treatment of presbyopia

    Science.gov (United States)

    Ripken, T.; Breitenfeld, P.; Fromm, M.; Oberheide, U.; Gerten, G.; Lubatschowski, H.

    2006-02-01

    The most probable reason for presbyopia is an age related loss of elasticity of the lens. It progresses typically during the whole life and at the age of about 45 it leads to a considerable loss of the ability to accommodate within the next decade. However, both, the ciliary muscle and the lens capsule stay active and elastic, respectively. With respect to this, one concept is to regain the deformability of the lens without changing the capsule or zonular apparatus. Since the investigations of Ripken et al. proofed that the flexibility of the presbyopic lens tissue can be increased through the creation of fs-laser induced microcuts inside the lens, this is one possible approach to treat presbyopia. On this account a finite-element-method model with ANSYS of the human lens during accommodation will be presented. The analysis premises all lens materials to be linear elastic and allow large displacements. A first analysis of this method for the treatment of presbyopia is accomplished. Therefore the mechanical analysis of untreated and treated lens are compared. In addition ex-vivo elasticity measurements of untreated and treated lenses will be presented. As a result an improvement of the flexibility of the lens tissue is found and as its consequence a change of the lens radii of curvature is established. After suitable processing of the output data the change in optical power between untreated and treated lenses are calculated. The finite element simulation shows similar behaviour compared to the treated porcine lenses.

  9. Apixaban and atrial fibrillation: no clear advantage.

    Science.gov (United States)

    2014-02-01

    For the prevention of thromboembolic events in patients with atrial fibrillation and a high thrombotic risk, the standard treatment is warfarin, an anticoagulant. Dabigatran, a thrombin inhibitor, is the alternative when warfarin fails to maintain the INR within the therapeutic range. Patients with a moderate thrombotic risk may receive either warfarin or low-dose aspirin. Apixaban, a factor Xa inhibitor anticoagulant, has been authorised in the European Union for use in patients with non-valvular atrial fibrillation and a moderate or high risk of thrombosis. In a double-blind, randomised non-inferiority trial versus warfarin in 18 201 patients, the incidence of stroke or systemic embolism was lower in the apixaban group (average 1.3 versus 1.6 events per 100 patient-years; p = 0.01). This difference was mainly due to a lower incidence of haemorrhagic stroke and did not result in a clear decline in mortality. In addition, these results are undermined by multiple methodological flaws. Clinical evaluation included no trials comparing apixaban with dabigatran; any indirect comparison would be risky given the poor quality of the clinical assessment of both drugs in atrial fibrillation. A double-blind, randomised trial including 5598 patients compared apixaban with aspirin but provided little information on these options in patients with a moderate risk of thrombosis, as most patients were at high risk. In clinical trials, major bleeding events were less frequent with apixaban than with warfarin (average 2.1 versus 3.1 events per 100 patient-years), but they were more frequent with apixaban than with aspirin (1.4 versus 0.9 events per 100 patient-years). In 2013, there is no way of monitoring the anticoagulant activity of apixaban in routine clinical practice, and there is no antidote in case of overdose; the same is true for dabigatran. Apixaban is a substrate for various cytochrome P450 isoenzymes and for P-glycoprotein, creating a risk of multiple drug

  10. Liquefaction for cataract extraction

    Science.gov (United States)

    Labiris, Georgios; Toli, Aspasia; Polychroni, Damaskini; Gkika, Maria; Angelonias, Dimitrios; Kozobolis, Vassilios P.

    2016-01-01

    A systematic review of the recent literature regarding the implementation of the liquefaction in cataract surgery and its short-term and long-term outcomes in various parameters that affect the quality of patients' life, including visual rehabilitation and possible complications was performed based on the PubMed, Medline, Nature and the American Academy of Ophthalmology databases in November 2013 and data from 14 comparative studies were included in this narrative review. Liquefaction is an innovative technology for cataract extraction that uses micropulses of balanced salt solution to liquefy the lens nucleus. Most studies reported that liquefaction is a reliable technology for mild to moderate cataracts, while fragmentation difficulties may be encountered with harder nuclei. PMID:26949656

  11. Effect of selenite on 86Rb uptake by rat lens

    International Nuclear Information System (INIS)

    The effect was observed in vitro of selenite on the uptake of 86Rb by the lens in two weeks old and adult rats. Also measured was the uptake of 86Rb by the lens in vitro in 30-days old rats with cataracts induced by the administration of selenite at day 14 after birth and in control animals of the same age. Selenite in a concentration of 0.4 mM and more caused an insignificant decrease in 86Rb uptake by the lens in adult rats while in the lens of young rats the uptake decreased significantly already at concentrations lower by two orders. Lenses with cataracts took up significantly less 86Rb than transparent lenses; body weight, the weight of the fresh lens and its dry mass decreased while the water content in the lens was higher as compared with control groups. (author). 2 tabs., 26 refs

  12. Shape measurement of aspheric plastic lens with large angle

    Institute of Scientific and Technical Information of China (English)

    Dagang Huang; Heng Zhang; Shah-Rong Lee; Baoguang Wang

    2005-01-01

    @@ In this paper, according to the features of easy distortion and scratch for aspheric plastic lens, a noncontact measuring method is raised to test error in shape of the lens. Namely, the distance between a template and its image reflected with tested lens can be measured in nearly the vertical direction of the lens axis when the two-dimensional (2D) template is put near the measured surface. Then, the outline of the central cross-section could be obtained by calculating and curve fitting. Furthermore, three-dimensional (3D) surface can be imitated through rotating the component. A new fitting method of drift measurement is presented to prevent reducing precision when the lens and the template are fixed. The template is adjusted according to the position of the lens. The measurement precision is in the order of magnitued of sub-microns. Rotationally symmetric convex aspheric surface with any angle can be measured by this method.

  13. Multipoint photonic doppler velocimetry using optical lens elements

    Science.gov (United States)

    Frogget, Brent Copely; Romero, Vincent Todd

    2014-04-29

    A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

  14. A passively tunable acoustic metamaterial lens for selective ultrasonic excitation

    International Nuclear Information System (INIS)

    In this paper, we present an approach to ultrasonic beam-forming and beam-steering in structures based on the concept of embedded acoustic metamaterial lenses. The lens design exploits the principle of acoustic drop-channel that enables the dynamic coupling of multiple ultrasonic waveguides at selected frequencies. In contrast with currently available technology, the embedded lens allows exploiting the host structure as a key component of the transducer system therefore enabling directional excitation by means of a single ultrasonic transducer. The design and the performance of the lens are numerically investigated by using Plane Wave Expansion and Finite Difference Time Domain techniques applied to bulk structures. Then, the design is experimentally validated on a thin aluminum plate waveguide where the lens is implemented by through-holes. The dynamic response of the embedded lens is estimated by reconstructing, via Laser Vibrometry, the velocity field induced by a single source located at the center of the lens

  15. Studies on the diffraction image of a thermal lens.

    Science.gov (United States)

    Jürgensen, F; Schröer, W

    1995-01-01

    We calculated the intensity distribution behind a thermal lens by using a numerical quadrature of the Fresnel diffraction integral and compared it to several given approximate models for laser light detection in the center behind a thermal lens, which includes a new approximate solution of the diffraction integral with applicability to strong thermal lenses. Consideration of the aberrant nature of the thermal lens is crucial even if the thermal lens is weak. A simple approximate formula for the position of the most intense interference ring stating a linear dependence of the thermal lens strength is given. The transverse profile of a weak thermal lens is discussed. It is shown that spherical aberration modifies the central intensity even if a Gaussian profile is observed. PMID:20963083

  16. Monoscleral fixation of IOL after extracapsular extraction of subluxated lenses in patients with Marfan syndrome Fixação monoescleral da LIO após extração extracapsular de cristalinos subluxados em pacientes com síndrome de Marfan

    OpenAIRE

    Vinícius Coral Ghanem; Emir Amin Ghanem; Ramon Coral Ghanem; Carlos Eduardo Leite Arieta

    2004-01-01

    PURPOSE: To describe a technique of monoscleral fixation of the intraocular lens (IOL) after extracapsular extraction of subluxated lens in patients with Marfan syndrome. Design: Noncomparative, interventional case series. METHODS: A retrospective study was conducted on 14 eyes of 7 consecutive patients with subluxated lens associated with Marfan syndrome. Surgery was indicated when: 1) a lens border was observed in the pupil area with the pupil under normal lighting causing glare; or 2) the ...

  17. Characterization and localization of side population cells in the lens

    OpenAIRE

    Oka, Mikako; Toyoda, Chizuko; Kaneko, Yuka; Nakazawa, Yosuke; Aizu-Yokota, Eriko; Takehana, Makoto

    2010-01-01

    Purpose Side population (SP) cells were isolated and the possibility whether lens epithelial cells contain stem cells was investigated. Methods Mouse lens epithelial cells were stained by Hoechst 33342 and then sorted by fluorescence-activated cell sorting (FACS). The expression of stem cell markers in sorted SP cells and the main population of epithelial cells were analyzed by quantitative real-time PCR. Localization of SP cells in the mouse lens was studied by fluorescence microscopy. Resul...

  18. Functions of the intermediate filament cytoskeleton in the eye lens

    OpenAIRE

    Song, Shuhua; Landsbury, Andrew; Dahm, Ralf; Liu, Yizhi; Zhang, Qingjiong; Quinlan, Roy A.

    2009-01-01

    Intermediate filaments (IFs) are a key component of the cytoskeleton in virtually all vertebrate cells, including those of the lens of the eye. IFs help integrate individual cells into their respective tissues. This Review focuses on the lens-specific IF proteins beaded filament structural proteins 1 and 2 (BFSP1 and BFSP2) and their role in lens physiology and disease. Evidence generated in studies in both mice and humans suggests a critical role for these proteins and their filamentous poly...

  19. Patient acceptability of the Tecnis® multifocal intraocular lens

    OpenAIRE

    Sood, Priyanka; Woodward, Maria A.

    2011-01-01

    Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients’ desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL) designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anterior prolate IOL with a diffractive multifocal lens design. The design aims to minimize spherical aberration and improve range of focus....

  20. Ring lens for focusing ion beams to uniform densities

    International Nuclear Information System (INIS)

    An electrostatic lens was designed and built to focus a beam of positive ions into uniform density on a target. The lens has two concentric field regions with a grid separating the inner zero field from the outer radial field. For proper operation the incident ions must emanate with axial symmetry and Gaussian or similar divergence from a small source. An appendix is included on the symmetrization of elliptical beams by a quadrupole singlet lens. (U.S.)

  1. Microbial Keratitis: Could Contact Lens Material Affect Disease Pathogenesis?

    OpenAIRE

    Evans, David J.; Fleiszig, Suzanne M. J.

    2013-01-01

    Microbial keratitis is a sight-threatening complication associated with contact lenses. The introduction of silicone hydrogel lens materials with increased oxygen transmission to the ocular surface has not significantly altered the incidence of microbial keratitis. These data suggest that alternate, or additional, predisposing factors involving lens wear must be addressed to reduce or eliminate these infections. The contact lens can provide a surface for microbial growth in situ, and can also...

  2. Goat′s eye integrated with a human cataractous lens: A training model for phacoemulsification

    OpenAIRE

    Sabyasachi Sengupta; Praveen Dhanapal; Manas Nath; Aravind Haripriya; Rengaraj Venkatesh

    2015-01-01

    A relatively simple and inexpensive technique to train surgeons in phacoemulsification using a goat's eye integrated with a human cataractous nucleus is described. The goat's eye is placed on a bed of cotton within the lumen of a cylindrical container. This is then mounted on a rectangular thermocol so that the limbus is presented at the surgical field. After making a clear corneal entry with a keratome, the trainer makes a 5–5.5 mm continuous curvilinear capsulorhexis in the anterior lens ca...

  3. 600 Volt Stretched Lens Array for Solar Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ENTECH, Auburn, NASA, and others have recently developed a new space photovoltaic array called the Stretched Lens Array (SLA), offering unprecedented performance...

  4. Reduction of pantethine in rabbit ocular lens homogenate.

    Science.gov (United States)

    Fisher, D H; Szulc, M E

    1997-02-01

    In several animal models, preliminary studies have indicated that pantethine may inhibit cataract formation. Therefore, preclinical trials need to be conducted to study the pharmacology of pantethine in the ocular lens and to establish its efficacy. Since pantethine, which is a disulfide, can undergo a variety of chemical modifications such as reduction and formation of mixed disulfides, a detailed study was first conducted to determine the stability of pantethine in rabbit lens homogenate. A knowledge of the stability of pantethine in lens homogenate was necessary to establish if pantethine could be metabolized in the time it takes to harvest and homogenize a lens. The results of this study will be used to establish a protocol for harvesting and homogenizing lens samples. Pantethine (100 microM) is completely reduced to pantetheine in rabbit lens homogenate in about 16 min. About 1.5% of the pantethine added to lens homogenate forms a mixed disulfide with lens proteins, and the remainder is found in the supernatant. The supernatant pantethine concentration decreases exponentially as a function of time, and the terminal half-life for this process is 3.3 min. The free supernatant pantetheine concentration increases in pseudo first order manner as a function of time with a rate constant of 4.3 min. Pantethinase activity is not significant, because the free supernatant pantetheine concentration did not decrease. The exact mechanism of pantethine reduction in rabbit lens homogenate remains to be determined. PMID:9127277

  5. Propagation of Lissajous singularities through an astigmatic lens

    International Nuclear Information System (INIS)

    The analytical expression for the propagation of Lissajous singularities through an astigmatic lens is derived and used to study the dynamic evolution of Lissajous singularities after passing through the astigmatic lens and the dependence of Lissajous singularities on the control parameters where the effect of astigmatism of the lens is stressed. It is shown that motion, pair creation and annihilation, handedness reversal and change in the degree of polarization of Lissajous singularities may take place. In particular, a single Lissajous singularity may appear and vanish due to the presence of the astigmatic lens

  6. Lens Extrusion from Laminin Alpha 1 Mutant Zebrafish

    OpenAIRE

    Mallika Pathania; Semina, Elena V; Duncan, Melinda K.

    2014-01-01

    We report analysis of the ocular lens phenotype of the recessive, larval lethal zebrafish mutant, lama1 a69/a69 . Previous work revealed that this mutant has a shortened body axis and eye defects including a defective hyaloid vasculature, focal corneal dysplasia, and loss of the crystalline lens. While these studies highlight the importance of laminin α1 in lens development, a detailed analysis of the lens defects seen in these mutants was not reported. In the present study, we analyze the le...

  7. An Ultrasonic Lens Design Based on Prefractal Structures

    Directory of Open Access Journals (Sweden)

    Sergio Castiñeira-Ibáñez

    2016-04-01

    Full Text Available The improvement in focusing capabilities of a set of annular scatterers arranged in a fractal geometry is theoretically quantified in this work by means of the finite element method (FEM. Two different arrangements of rigid rings in water are used in the analysis. Thus, both a Fresnel ultrasonic lens and an arrangement of rigid rings based on Cantor prefractals are analyzed. Results show that the focusing capacity of the modified fractal lens is better than the Fresnel lens. This new lens is believed to have potential applications for ultrasonic imaging and medical ultrasound fields.

  8. Lens regeneration in axolotl: new evidence of developmental plasticity

    Directory of Open Access Journals (Sweden)

    Suetsugu-Maki Rinako

    2012-12-01

    Full Text Available Abstract Background Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration. Frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. The axolotl is another salamander which, like the newt, regenerates its limbs or its tail with the spinal cord, but up until now all reports have shown that it does not regenerate the lens. Results Here we present a detailed analysis during different stages of axolotl development, and we show that despite previous beliefs the axolotl does regenerate the lens, however, only during a limited time after hatching. We have found that starting at stage 44 (forelimb bud stage lens regeneration is possible for nearly two weeks. Regeneration occurs from the iris but, in contrast to the newt, regeneration can be elicited from either the dorsal or the ventral iris and, occasionally, even from both in the same eye. Similar studies in the zebra fish concluded that lens regeneration is not possible. Conclusions Regeneration of the lens is possible in the axolotl, but differs from both frogs and newts. Thus the axolotl iris provides a novel and more plastic strategy for lens regeneration.

  9. Seeing lens imaging as a superposition of multiple views

    CERN Document Server

    Grusche, Sascha

    2015-01-01

    In the conventional approach to lens imaging, rays are used to map object points to image points. However, many students have a need to think of the image as a whole. To answer this need, lens imaging is reinterpreted as a superposition of sharp images from different viewpoints. These so-called elemental images are uncovered by covering the lens with a pinhole array. Rays are introduced to connect elemental images. Lens ray diagrams are constructed based on bundles of elemental images. The conventional construction method is included as a special case. The proposed approach proceeds from concrete images to abstract rays.

  10. Seeing lens imaging as a superposition of multiple views

    Science.gov (United States)

    Grusche, Sascha

    2016-01-01

    In the conventional approach to lens imaging, rays are used to map object points to image points. However, many students want to think of the image as a whole. To answer this need, Kepler’s ray drawing is reinterpreted in terms of shifted camera obscura images. These images are uncovered by covering the lens with pinholes. Thus, lens imaging is seen as a superposition of sharp images from different viewpoints, so-called elemental images. This superposition is simulated with projectors, and with transparencies. Lens ray diagrams are constructed based on elemental images; the conventional construction method is included as a special case.

  11. Assessing the elasticity change of cataract lens with OCE

    Science.gov (United States)

    Wu, Chen; Liu, Chih-Hao; Raghunathan, Raksha; Singh, Manmohan; Li, Jiasong; Han, Zhaolong; Larin, Kirill V.

    2016-03-01

    Cataract is one of the most common degenerative diseases that causes blindness. Careful quantification of lens biomechanical properties can greatly assist in early detection of the disease as well as personalization of treatment procedures. In this study, we utilize a phase-sensitive optical coherence elastography (OCE) system to assess the effects of the cold cataract on the biomechanical properties of porcine crystalline lens in vitro. Relaxation rates of air puff induced elastic waves were measured on the same crystalline lens with and without cold cataract. Results demonstrate that the relaxation rate and, thus, associated elasticity of the porcine lens, increased due to the presence of cold cataract.

  12. Experimental investigation and analysis on a concentrating solar collector using linear Fresnel lens

    International Nuclear Information System (INIS)

    A concentrating solar collector based on linear Fresnel lens is investigated experimentally in this paper. This solar collector is expected to acquire a higher thermal efficiency at a relatively high temperature level than the commonly used flat-plate or evacuated tube solar collectors. Experimental results show that the thermal efficiency is about 50% when the conversion temperature (water) is 90 deg. C. The test shows that the indication of lost energy is 0.578 W/m2 K, which is much smaller than that of commonly used evacuated tube solar collector without concentrating. In order to make analysis, a mathematical model for evacuated tube absorber heated by linear Fresnel lens has been built. The validation shows that the model agrees with the experimental data well. The analysis indicates that Fresnel lens collector with evacuated tube absorber has good efficiency (50%) in clear day even when the conversion temperature approaches 200 deg. C. The influence of ambient conditions and the percent of different types of energy loss, etc., are also analyzed.

  13. Clear Cell Basal Cell Carcinoma with Sialomucin Deposition

    OpenAIRE

    Kim, Do Young; Cho, Sung Bin; Chung, Kee Yang; Kim, You Chan

    2006-01-01

    Clear cell basal cell carcinoma (BCC) is a variant of BCC with a characteristic clear cell component that may occupy all or part of the tumor islands. Periodic acid-Schiff (PAS) staining for glycogen is variably positive, and mild deposition of sulfated mucin has been noted. However, to our knowledge, clear cell BCC with sialomucin deposition has not been reported. Here we report a case of clear cell BCC showing sialomucin deposition. The clear tumor cells stained with PAS and showed incomple...

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

    Czech Academy of Sciences Publication Activity Database

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

    2007-01-01

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

  15. The BOSS Emission-Line Lens Survey. IV. : Smooth Lens Models for the BELLS GALLERY Sample

    CERN Document Server

    Shu, Yiping; Mao, Shude; Kochanek, Christopher S; Pérez-Fournon, Ismael; Oguri, Masamune; Montero-Dorta, Antonio D; Cornachione, Matthew A; Marques-Chaves, Rui; Zheng, Zheng; Brownstein, Joel R; Ménard, Brice

    2016-01-01

    We present \\textsl{Hubble Space Telescope} (\\textsl{HST}) F606W-band imaging observations of 21 galaxy-Ly$\\alpha$ emitter lens candidates in the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey (BELLS) for GALaxy-Ly$\\alpha$ EmitteR sYstems (BELLS GALLERY) survey. 17 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$\\alpha$ emitters (LAEs) at redshifts from 2 to 3. Although the \\textsl{HST} imaging data 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 which will allow a detailed investigation of the radius evolution of the mass profile...

  16. Magnetic Resonance Imaging with a Dielectric Lens

    CERN Document Server

    Vazquez, F; Martin, R; Rodriguez, A O

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circular coil to generate phantom images at 3 Tesla on a clinical MR imager.

  17. Liquid crystal adaptive lens with circular electrodes

    Science.gov (United States)

    Sun, Yi

    The liquid crystal adaptive lens (LCAL) developed in this research is an electro-optical device using a set of electrodes to grade the refractive index across its aperture. Adjusting the applied voltages permits continuous control of focal length. The first effort at developing an LCAL using circular electrodes to provide a simpler architecture than previous devices using linear electrodes is presented in this dissertation. A theoretical study for an LCAL with circular electrodes is performed. The liquid crystal behavior and the applied voltage profile required for different focal lengths is discussed. Numerical simulation of the refractive index change and the Point Spread Function is developed to study the aberrations and predict performance with circular electrode geometry. A Fresnel lens phase profile is applied to yield a lens with a useful F-number, and a previously unexplored aberration is identified and characterized. An LCAL prototype was designed with a set of high-density electrodes in the conductive ladder meshing configuration, which results in a small number of externally controlled electrodes. A new electronic controller was designed and built with a fast response and accurate output to apply the voltage set to the LCAL. An electro-optical feedback control system based on LabVIEW software was developed to optimize control output voltages using signals from a CID camera. A prototype LCAL was designed with a 7.86 mm diameter aperture and a focal length adjustable from 0.2 m to infinity. It was fabricated on a glass substrate with two layers of transparent electrodes, insulating layers, and vias to connect the two conducting layers. The special fabrication challenges involved are discussed. Focusing experiments were performed by auto-dithering using the electro-optical feedback control system. The point spread function measurement results are presented, demonstrating that the focal spot size reaches the diffraction limit, but astigmatism created by the

  18. LensTools: Weak Lensing computing tools

    Science.gov (United States)

    Petri, A.

    2016-02-01

    LensTools implements a wide range of routines frequently used in Weak Gravitational Lensing, including tools for image analysis, statistical processing and numerical theory predictions. The package offers many useful features, including complete flexibility and easy customization of input/output formats; efficient measurements of power spectrum, PDF, Minkowski functionals and peak counts of convergence maps; survey masks; artificial noise generation engines; easy to compute parameter statistical inferences; ray tracing simulations; and many others. It requires standard numpy and scipy, and depending on tools used, may require Astropy (ascl:1304.002), emcee (ascl:1303.002), matplotlib, and mpi4py.

  19. Hyperbolic metamaterial lens with hydrodynamic nonlocal response

    DEFF Research Database (Denmark)

    Yan, Wei; Mortensen, N. Asger; Wubs, Martijn

    2013-01-01

    We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves...... of the free-electron plasma in the metal constituents. We derive the nonlocal corrections to the effective material parameters analytically, and illustrate the noticeable nonlocal effects on the dispersion curves numerically. As an application, we find that the focusing characteristics of a HMM lens...

  20. Comparison of Strong Gravitational Lens Model Software II. HydraLens: Computer-Assisted Strong Gravitational Lens Model Generation and Translation

    CERN Document Server

    Lefor, Alsn T

    2015-01-01

    The behavior of strong gravitational lens model software in the analysis of lens models is not necessarily consistent among the various software available, suggesting that the use of several models may enhance the understanding of the system being studied. Among the publicly available codes, the model input files are heterogeneous, making the creation of multiple models tedious. An enhanced method of creating model files and a method to easily create multiple models, may increase the number of comparison studies. HydraLens simplifies the creation of model files for four strong gravitational lens model software packages, including Lenstool, Gravlens/Lensmodel, glafic and PixeLens, using a custom designed GUI for each of the four codes that simplifies the entry of the model for each of these codes, obviating the need for user manuals to set the values of the many flags and in each data field. HydraLens is designed in a modular fashion, which simplifies the addition of other strong gravitational lens codes in th...

  1. Performance of a slow positron beam using a hybrid lens design

    International Nuclear Information System (INIS)

    The University of Hong Kong positron beam employs conventional magnetic field transport to the target, but has a special hybrid lens design around the positron moderator that allows the beam to be focused to millimeter spot sizes at the target. The good focusing capabilities of the beam are made possible by extracting work-function positrons from the moderator in a magnetic field free region using a conventional Soa lens thus minimizing beam canonical angular momentum. An Einzel lens is used to focus the positrons into the magnetic funnel at the end of transportation magnetic field while at the same time bringing up the beam energy to the intermediate value of 7.5 keV. The beam is E x B filtered at this intermediate energy. The final beam energy is obtained by floating the Soa-Einzel system, E x B filter and flight tube, and accelerating the positrons just before the target. External beam steering saddle coils fine tune the position, and the magnetic field around the target chamber is adjusted so as to keep one of the beam foci always on the target. The system is fully computer controlled. Variable energy-Doppler broadened annihilation radiation (VEDBAR) data for a GaN sample are shown which demonstrate the performance of the positron beam system

  2. Deterministic effect of lens at leukergy of patients who received low doses of ionising radiation

    International Nuclear Information System (INIS)

    To explore the possibility to use the lens extract as an in vitro stimulator to conduct a test of stimulated leukergy in liquidators of the accident consequences (LAC) on Chernobyl Nuclear Power Plant (CNPP) with a cataract in the long-term period. The study sample included 72 men-LAC on CNPP, at the age from 42 to 65 y, who have a cataract. The comparison group consisted of 60 men, with a cataract, of the same age, and who were not exposed to radiation. The control group was composed of 60 men, at the age of 42-58 y without lens pathology. Phenomenon of the stimulated leukergy was revealed in persons who had been exposed to radiation in the dose of 18.2±0.58 cGy and was observed in 5.7- 8.05 % (P < 0.001), suggesting a continued high auto-aggression to the lens antigens, and the strength of cell-mediated immunity (authors)

  3. Increasing a freshwater lens below a creek ridge using a controlled artificial recharge and drainage system: a case study in the Netherlands

    Science.gov (United States)

    Pauw, Pieter S.; van Baaren, Esther S.; Visser, Martijn; de Louw, Perry G. B.; Essink, Gualbert H. P. Oude

    2015-11-01

    A controlled artificial recharge and drainage (CARD) system was used to increase freshwater lenses below creek ridges to increase freshwater supply. Creek ridges are typical geomorphological features that lie up to 2 m higher than the surroundings in the reclaimed tidal flat landscape of the southwestern Netherlands. The 5-30-m thick freshwater lenses below the creek ridges are a vital source for irrigation, as the groundwater and surface waters are predominantly saline. However, freshwater supply from these lenses is commonly not sufficient to meet the irrigation demand, which leads to crop damage. The CARD system was tested in the field and the development of the freshwater lens was monitored during the period May 2013 to May 2014. Numerical models, which were used to investigate a long-term effect of the CARD system, predicted that below the center of the creek ridge, the 13-15-m thick freshwater lens increased 6-8 m within 10 years. The total volumetric increase of the freshwater lens was about 190,000 m3 after 10 years, which was about 40 % of the total recharge (natural and artificial recharge). From this increased freshwater lens, up to three times more water can be extracted using horizontal wells, compared to the initial size of the freshwater lens. A higher water table in the CARD system leads to a thicker freshwater lens but a lower storage efficiency. A lower water table has the opposite effect.

  4. The Effect of Contact Lens Usage on Corneal Biomechanical Parameters in Keratoconus Patients

    Directory of Open Access Journals (Sweden)

    Ali Bülent Çankaya

    2012-05-01

    Full Text Available Pur po se: To determine and compare the corneal biomechanical properties in keratoconus patients using rigid gas permeable contact lenses and keratoconus patients who do not use contact lenses. Ma te ri al and Met hod: The study consisted of 70 healthy controls (Group A, 27 ketatoconus subjects who do not use contact lens (Group B and 36 rigid gas permeable contact lens using keratoconic patients (Group C. Corneal viscoelastic parameters were measured with an Ocular response analyzer (ORA. Central corneal thickness was measured with an ultrasonic pachymeter. The differences in ORA parameters between the groups were compared. Re sults: The mean corneal hysteresis (CH in Groups A, B, and C were 10.3±1.5 mm Hg, 7.8±1.4 mm Hg, and 7.4±1.2 mm Hg, respectively. The differences in mean CH between Group A and the other two groups were statistically significant (p<0.01 for both comparisons, but no statistically significant difference was found between groups B and C in terms of mean CH (p=0.61. The mean corneal resistance factor (CRF was 10.7±1.9 in Group A compared with 6.6±1.6 in Group B and 6.1±1.5 in Group C. The differences in mean CRF between Group A and the other two groups were statistically significant (p<0.01 for both comparisons. There was no significant difference in CRF between the keratoconus eyes with or without rigid gas permeable contact lens usage (p=0.57. Dis cus si on: Our results suggest that ORA-generated parameters may be different in subjects with keratoconus. Corneal biomechanical parameters did not demonstrate a clear trend of change with rigid gas permeable contact lens usage. (Turk J Ophthalmol 2012; 42: 197-201

  5. Fusarium and Candida albicans biofilms on soft contact lenses: model development, influence of lens type and susceptibility to lens care solutions

    Science.gov (United States)

    Fungal keratitis is commonly caused by Fusarium species, while cases of Candida-associated keratitis are less frequent. Recent outbreaks of Fusarium keratitis were associated with contact lens wear and with MoistureLoc contact lens care solution, and biofilm formation on contact lens/lens cases was...

  6. Atomic force microscopy and Langmuir–Blodgett monolayer technique to assess contact lens deposits and human meibum extracts☆

    Science.gov (United States)

    Hagedorn, Sarah; Drolle, Elizabeth; Lorentz, Holly; Srinivasan, Sruthi; Leonenko, Zoya; Jones, Lyndon

    2015-01-01

    Purpose The purpose of this exploratory study was to investigate the differences in meibomian gland secretions, contact lens (CL) lipid extracts, and CL surface topography between participants with and without meibomian gland dysfunction (MGD). Methods Meibum study: Meibum was collected from all participants and studied via Langmuir–Blodgett (LB) deposition with subsequent Atomic Force Microscopy (AFM) visualization and surface roughness analysis. CL Study: Participants with and without MGD wore both etafilcon A and balafilcon A CLs in two different phases. CL lipid deposits were extracted and analyzed using pressure-area isotherms with the LB trough and CL surface topographies and roughness values were visualized using AFM. Results Meibum study: Non-MGD participant meibum samples showed larger, circular aggregates with lower surface roughness, whereas meibum samples from participants with MGD showed more lipid aggregates, greater size variability and higher surface roughness. CL Study: Worn CLs from participants with MGD had a few large tear film deposits with lower surface roughness, whereas non-MGD participant-worn lenses had many small lens deposits with higher surface roughness. Balafilcon A pore depths were shallower in MGD participant worn lenses when compared to non-MGD participant lenses. Isotherms of CL lipid extracts from MGD and non-MGD participants showed a seamless rise in surface pressure as area decreased; however, extracts from the two different lens materials produced different isotherms. Conclusions MGD and non-MGD participant-worn CL deposition were found to differ in type, amount, and pattern of lens deposits. Lipids from MGD participants deposited irregularly whereas lipids from non-MGD participants showed more uniformity. PMID:25620317

  7. Influence of age, corneal astigmatism and some characteristics of intraocular lens on glare in pseudophakic persons

    Directory of Open Access Journals (Sweden)

    Avramović Siniša

    2007-01-01

    Full Text Available Background/Aim. Although an extraordinary visual acuity is achieved following the extracapsular cataract extraction with the implantation of intraocular lens, all the problems of vision are not solved in so doing and many of them should be considered. The aim of this study was to establish the influence of age, dioptric power of intraocular lens, corneal astigmatism and optic diameter of intraocular lens on glare in pseudophakic subjects. Methods. We examined 152 patients who underwent final correction at least two weeks after the suture removing what was performed if the astigmatism more than 2.0 D was measured by the use of a Javal keratometer. Examination was performed by a Rodenstock Adaptometer Nyctomat. According to the recommendation of the manufacturer, healthy persons should notice 50% of contrast under the constant glare and in the given time. Statistical data processing was performed by χ2 test. Results. In the group of patients with the findings lower than normal at constant glare there were 112 of eyes (73.68% as follows: 22 eyes (14.47% at the age from 50-55 years; 15 eyes (9.87% were at the age from 56-60 years; 18 eyes (11.84% were at the age from 61-65 years, and 57 eyes (37.50% were at the age from 66-70 years. Dioptric power of lenses up to 20.0 D had 37 eyes (24.3%, from 20.5-22.0 D 85 eyes (56.9% and more than 22.5 D, 27 eyes (17.8%. Regarding the results of discomfort caused by glare and corneal astigmatism, measured by a Javal keratometer, in the observed group normal results were found in 112 eyes (73.68%, and out of that number 95 (62.50% were with corneal astigmatism less than 20.0 D, and 17 (11.18% had astigmatism of 20.0 D and more. Out of 112 eyes there were 58 of them (38.16% with findings lower than normal in relation to the constant glare and with the lens diameter of 5.5 mm, 48 (31.58% with the lens diameter of 6.0mm, and 6 of them (3.95% with lens diameter of 6.5mm. Conclusion. The study determined a

  8. High Dk piggyback contact lens system for contact lens-intolerant keratoconus patients

    Directory of Open Access Journals (Sweden)

    Tomris Sengor

    2011-03-01

    Full Text Available Tomris Sengor, Sevda Aydin Kurna, Suat Aki, Yelda ÖzkurtFatih Sultan Mehmet Training and Research Hospital, Istanbul, TurkeyBackground: The aim of the study was to examine the clinical success of high Dk (oxygen permeability piggyback contact lens (PBCL systems for the correction of contact lens intolerant keratoconus patients.Methods: Sixteen patients (29 eyes who were not able to wear gas-permeable rigid lenses were included in this study. Hyper Dk silicone hydrogel (oxygen transmissibility or Dk/t = 150 units and fluorosilicone methacrylate copolymer (Dk/t = 100 units lenses were chosen as the PBCL systems. The clinical examinations included visual acuity and corneal observation by biomicroscopy, keratometer reading, and fluorescein staining before and after fitting the PBCL system.Results: Indications for using PBCL system were: lens stabilization and comfort, improving comfort, and adding protection to the cone. Visual acuities increased significantly in all of the patients compared with spectacles (P = 0. Improvement in visual acuity compared with rigid lenses alone was recorded in 89.7% of eyes and no alteration of the visual acuity was observed in 10.3% of the eyes. Wearing time of PBCL systems for most of the patients was limited time (mean 6 months, range 3–12 months; thereafter they tolerated rigid lenses alone except for 2 patients.Conclusion: The PBCL system is a safe and effective method to provide centering and corneal protection against mechanical trauma by the rigid lenses for keratoconus patients and may increase contact lens tolerance.Keywords: piggyback contact lens, keratoconus, irregular astigmatism

  9. Stochastic heterogeneity mapping around a Mediterranean salt lens

    Directory of Open Access Journals (Sweden)

    G. G. Buffett

    2010-01-01

    Full Text Available We present the first application of stochastic heterogeneity mapping based on the band-limited von Kármán function to a seismic reflection stack of a Mediterranean water eddy (meddy, a large salt lens of Mediterranean water. This process extracts two stochastic parameters directly from the reflectivity field of the seismic data: the Hurst number, which ranges from 0 to 1, and the correlation length (scale length. Lower Hurst numbers represent a richer range of scale lengths and correspond to a broader range of reflection events. The Hurst number estimate for the top of the meddy (0.39 compares well with recent theoretical work, which required values between 0.25 and 0.5 to model internal wave surfaces in open ocean conditions based on simulating a Garrett-Munk spectrum (GM76 slope of −2. Varying stochastic parameters, which correspond to different spectral slopes in the Garrett-Munk spectrum (horizontal wavenumber spectrum, can therefore provide an estimate of different internal wave scales from seismic data alone.

  10. The extractant

    International Nuclear Information System (INIS)

    The extractant for extraction and re-extraction of heavy metal ions has been worked out. The extractant consists of ferromagnetic particles suspended in liquid and covered by unsaturated fatty acids. The liquid, unsoluble in other liquids taken part in the process, contains also an organic derivative of phosphoric acid as a complexing agent

  11. Tubular astigmatism-tunable fluidic lens.

    Science.gov (United States)

    Kopp, Daniel; Zappe, Hans

    2016-06-15

    We demonstrate a new means to fabricate three-dimensional liquid lenses which may be tuned in focal length and astigmatism. Using actuation by electrowetting-on-dielectrics, astigmatism in arbitrary directions may be tuned independently, with almost no cross talk between orthogonal orientations. The lens is based on electrodes structured on planar polyimide foils and subsequently rolled, enabling high-resolution patterning of complex electrodes along the azimuthal and radial directions of the lens. Based on a design established through fluidic and optical simulations, the astigmatism tuning is experimentally verified by a change of the corresponding Zernike coefficients measured using a Shack-Hartmann wavefront sensor. It was seen that the back focal length can be tuned by 5 mm and 0° and 45° astigmatism by 3 μm through application of voltages in the range of 50  Vrms. It was observed that the cross talk with other aberrations is very low, suggesting a novel means for astigmatism control in imaging systems. PMID:27304276

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

    Science.gov (United States)

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

    2012-09-01

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

  13. Metamaterial radiofrequency lens for magnetic resonance imaging

    CERN Document Server

    Freire, Manuel J; Jelinek, Lukas; Gil, Eduardo; Moya, Francisco

    2009-01-01

    The purpose of this work is to test the ability of a new class of passive electromagnetic device to increase the penetration depth of phased arrays of surface coils for magnetic resonance (MR) imaging systems. This new device is based on the emerging technology of metamaterials and behaves like a lens for the radiofrequency magnetic fields. The presented device was tested in several 1.5-T MR systems from different companies in combination with different phased arrays. One of the authors was enrolled as volunteer for the experiments. In these experiments his knees were imaged by using a dual phased array. The device was placed between the knees to check that the penetration depth of the coils was improved by this passive device. In all the experiments the presented device was successfully tested and it was checked that the knees of the volunteer can be imaged at deeper distances and that the signal-to-noise-ratio (SNR) in the obtained MR images was improved by the presence of the lens. The presented device has...

  14. Non-linear cluster lens reconstruction

    CERN Document Server

    Kaiser, N

    1994-01-01

    We develop a method for general non-linear cluster lens reconstruction using the observable distortion of background galaxies. The distortion measures the combination \\gamma/(1-\\kappa) of shear \\gamma and surface density \\kappa. From this we obtain an expression for the gradient of \\log (1 - \\kappa) in terms of directly measurable quantities. This allows one to reconstruct 1 - \\kappa up to an arbitrary constant multiplier. Recent work has emphasised an ambiguity in the relation between the distortion and \\gamma/(1-\\kappa). Here we show that the functional relation depends only on the parity of the images, so if one has data extending to large radii, and if the critical lines can be visually identified (as lines along which the distortion diverges), this ambiguity is resolved. Moreover, we show that for a generic 2-dimensional lens it is possible to locally determine the parity from the distortion. The arbitrary multiplier, which may in fact take a different value in each region bounded by the contour \\kappa =...

  15. Scleral lens for keratoconus: technology update

    Directory of Open Access Journals (Sweden)

    Rathi VM

    2015-10-01

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

  16. Cataract extraction without retrobulbar anaesthetic injection.

    OpenAIRE

    Smith, R

    1990-01-01

    Extracapsular cataract extraction with lens implant under local anaesthesia consisting of amethocaine drops followed by a simple subconjunctival injection in the upper part of the globe but without a retrobulbar injection was carried out in 175 eyes of 165 patients. The purpose of the study was to establish the feasibility of this type of anaesthesia in cataract surgery with the principal object of avoiding the possibility of retrobulbar haemorrhage and the other, rarer, complications of retr...

  17. Primary defects in the lens underlie complex anterior segment abnormalities of the Pax6 heterozygous eye

    OpenAIRE

    Collinson, J. Martin; Quinn, Jane C.; Buchanan, Malcolm A.; Kaufman, Matthew H.; Wedden, Sarah E.; West, John D.; Hill, Robert E.

    2001-01-01

    We describe lens defects in heterozygous small eye mice, and autonomous deficiencies of Pax6+/− cells in the developing lens of Pax6+/+ ↔ Pax6+/− chimeras. Two separate defects of the lens were identified by analyzing the distribution of heterozygous cells in chimeras: Pax6+/− cells are less readily incorporated into the lens placode than wild type, and those that are incorporated into the lens are not maintained efficiently in the proliferating lens epithelium...

  18. Calculation of Light Distribution on a Focal Plane of a Contact Lens Carved Fresnel Zone Plate

    OpenAIRE

    NAMEDA, Naoyoshi; ナメダ, ナオヨシ; 行田, 尚義

    1993-01-01

    A bifocal lens function has been difficult to achieve in a contact lens. As a solution to the problem, a diffraction bifocal contact lens was developed by Freeman in 1982. This report shows the results of the calculation of light distribution condensed by a diffraction type contact lens. This lens gives near vision focal length by first order subsidiary light, and far vision focal length by Oth order subsidiary light of the refraction power of the lens. The method followed in this inves...

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

    Science.gov (United States)

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

    2014-01-01

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

  20. Lens customization method to minimize aberration in integral imaging

    Science.gov (United States)

    Miranda, Matheus; Kim, Jonghyun; Hong, Keehoon; Lee, Byoungho

    2015-10-01

    Conventionally the elemental lenses of the lens-array used in integral imaging have spherical surface profiles, thus they suffer from intrinsic lens aberrations such as spherical aberration and astigmatism. Aberrations affect the ability of the lens to focus light in a single point, or to collimate light from a point source. In integral imaging, this results in a loss of image quality of the reconstructed image due to distortions. The viewing characteristics of the integral imaging system, such as viewing angle and image resolution, are also affected by aberrations. We propose the use of a custom made aspherical lens-array which was specifically designed to minimize distortions due to aberrations and hence improve the reconstructed image quality. Ray optics calculations are used in order to analyze the aberrations and find the initial lens surface profile. Lens optimization is performed with the aid of numerical simulation software. The designed lens-array is compared to a conventional spherical lens-array of same properties. The design, optimization, and fabrication processes are described and the experiments are presented and compared with the computer simulations.

  1. Opaque Contact Lens For Tracking Motion Of Eye

    Science.gov (United States)

    Zografos, James L., II; Gibson, Charles R.

    1993-01-01

    Opaque contact lens facilitates measurements of movements of eye; particularly, torsional movements. Lens, marked with pair of indices at diameter of 0.5 mm, provides stable, high-contrast reference for measurements of angular position and velocity of eye by use of video-image-analysis techniques. Intended for use in experiments on response of eye to vestibular balance mechanism.

  2. Electromagnetic modes of Maxwell fish-eye lens

    CERN Document Server

    Rosu, H C

    1996-01-01

    We provide an analysis of the radial structure of TE and TM modes of the Maxwell fisheye lens, by means of Maxwell equations as applied to the fisheye case. Choosing a lens of size R = 1 cm, we plot some of the modes in the infrared range.

  3. Bioinspired solid-liquid mixed tunable lens with multilayered structure

    Science.gov (United States)

    Liang, Dan; Wang, Xuan-Yin; Du, Jia-Wei

    2015-06-01

    A solid-liquid mixed tunable lens with multilayered structure is proposed. The designed lens utilizes a solid-state elastic polymer, optical liquid, and glass as the optical medium, and adjusts the focus by changing the surface curvature of the elastic polymer. The integrated structure of the tunable lens is presented, as well as detailed descriptions of the lens materials, fabrication, and assembling process. Images captured through the tunable lens under different displacement loads are presented, and the relationship among the displacement load, curvature radius, and effective focal length is analyzed. Additionally, the optical property of the tunable lens is simulated using the ZEMAX software. A change in focal length from 14.8 mm to 30 mm is demonstrated within the tiny 0.12 mm variation of the displacement load. Numerical analyses show that the lens distortion is less than 2%, and the modulation transfer function reaches 67 line pairs per mm. The solid-liquid mixed tunable lens shows the potential for developing a compact, low-aberration, and stable optical system.

  4. Isofocusing and immunological investigations on cephalopod lens proteins

    NARCIS (Netherlands)

    Brahma, S.K.; Lancieri, M.

    1979-01-01

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

  5. 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...

  6. The linear Fresnel lens solar concentrator: Transverse tracking error effects

    Science.gov (United States)

    Cosby, R. M.

    1977-01-01

    The solar concentration performance of a line focusing, flat base Fresnel lens in the presence of small transverse tracking errors was analyzed. Solar transmittance of the lens and focal plane imaging characteristics were evaluated. Transmission losses by reflectance and material absorption were also studied.

  7. Unilateral phacoemulsification and intraocular lens implantation in a dachshund

    OpenAIRE

    Kopala, Robyn L.

    2008-01-01

    A 1.5-year-old, spayed, female dachshund was presented with a cataract and lens-induced uveitis in the left eye. The cataract progressed from immature to hypermature in 4 months. Phacoemulsification and intraocular lens implantation was performed and the dog remains visual in the left eye 1 year post-surgery.

  8. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

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

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

    KAUST Repository

    Wang, Qiu

    2015-02-12

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

  10. The NNEST lens non native english speakers in TESOL

    CERN Document Server

    Mahboob, Ahmar

    2010-01-01

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

  11. 21 CFR 886.1415 - Ophthalmic trial lens frame.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens frame. 886.1415 Section 886.1415 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1415 Ophthalmic trial lens frame....

  12. Multifunctional metasurface lens for imaging and Fourier transform

    Science.gov (United States)

    Wen, Dandan; Yue, Fuyong; Ardron, Marcus; Chen, Xianzhong

    2016-06-01

    A metasurface can manipulate light in a desirable manner by imparting local and space-variant abrupt phase change. Benefiting from such an unprecedented capability, the conventional concept of what constitutes an optical lens continues to evolve. Ultrathin optical metasurface lenses have been demonstrated based on various nanoantennas such as V-shape structures, nanorods and nanoslits. A single device that can integrate two different types of lenses and polarities is desirable for system integration and device miniaturization. We experimentally demonstrate such an ultrathin metasurface lens that can function either as a spherical lens or a cylindrical lens, depending on the helicity of the incident light. Helicity-controllable focal line and focal point in the real focal plane, as well as imaging and 1D/2D Fourier transforms, are observed on the same lens. Our work provides a unique tool for polarization imaging, image processing and particle trapping.

  13. Dielectric Optical-Controlled Magnifying Lens by Nonlinear Negative Refraction

    CERN Document Server

    Cao, Jianjun; Zheng, Yuanlin; Chen, Xianfeng; Liang, Xiaogan; Wan, Wenjie

    2014-01-01

    A simple optical lens plays an important role for exploring the microscopic world in science and technology by refracting light with tailored spatially varying refractive index. Recent advancements in nanotechnology enable novel lenses, such as, superlens, hyperlens, Luneburg lens, with sub-wavelength resolution capabilities by specially designing materials' refractive indices with meta-materials and transformation optics. However, these artificially nano/micro engineered lenses usually suffer high losses from metals and are highly demanding in fabrication. Here we experimentally demonstrate for the first time a nonlinear dielectric magnifying lens using negative refraction by degenerate four-wave mixing in a plano-concave glass slide, obtaining magnified images. Moreover, we transform a nonlinear flat lens into a magnifying lens by introducing transformation optics into nonlinear regime, achieving an all-optical controllable lensing effect through nonlinear wave mixing, which may have many potential applicat...

  14. Status of eye lens radiation dose monitoring in European hospitals.

    Science.gov (United States)

    Carinou, Eleftheria; Ginjaume, Merce; O'Connor, Una; Kopec, Renata; Sans Merce, Marta

    2014-12-01

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. PMID:25222935

  15. Lens aberration measurement and analysis using a novel pattern

    Science.gov (United States)

    Nam, Byung-Ho; Cho, Byeong-Ho; Park, Jong O.; Kim, Dong-Seok; Baek, SungJin; Jeong, JongHo; Nam, ByungSub; Hwang, Young J.; Song, Young Jin

    2001-09-01

    Lens aberration of the exposure tool causes pattern deformation and position shift. As design rule shrinks, the ratio of printed feature size to applied wavelength for optical lithography is driven inexorably toward resolution limit. In this study, we devised an efficient method to evaluate lens aberration using multi-ring pattern on an attenuated phase-shift mask. Adoption of multi-ring pattern can cut down measurement time and improve measurement repeatability. These patterns are uniformly distributed through entire field in 7 by 7 manner. Lens aberration was evaluated by multi-ring pattern array under conventional or off-axis illumination with KrF stepper of NA 0.65. Multi-ring critical dimension (CD) data was discussed together with the issue of lens aberration such as coma, astigmatism, field curvature, etc. We can apply this new measurement technique to select better lens system efficiently. multi-ring, field size, pattern deformation

  16. Patient acceptability of the Tecnis® multifocal intraocular lens

    Directory of Open Access Journals (Sweden)

    Sood P

    2011-03-01

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

  17. Cellulose based soft gel like actuator for reconfigurable lens array

    Science.gov (United States)

    Sadasivuni, Kishor Kumar; Yadav, Mithilesh; Gao, Xiaoyuan; Mun, Seongcheol; Kim, Jaehwan

    2014-04-01

    Reconfigurable lens is biomimetic as it mimics human eye and is a transparent actuating material that can change its curvature in the presence of external stimuli. Focus tunable, adaptive lenses provide several advantages over traditional lens assemblies in terms of compactness, cost, efficiency and flexibility. To further improve the simplicity and compact nature of adaptive lenses, we present lens system which makes use of an inline, transparent electro active polymer actuator. This paper reports the preliminary development we have achieved in reconfigurable lens systems made with cellulose nanocrystals (CNC) using the principle of Kerr effect. Preparation of the hydrophobic CNC solution as well as the optical properties of the lens has been discussed. This soft gel actuator was analyzed by measuring the electric birefringence in the pulse field of constant and sinusoidal voltage based on the use of modulation of elliptic light polarization.

  18. Gabor lens focusing of a negative ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Palkovic, J.A.; Mills, F.E.; Schmidt, C.; Young, D.E.

    1989-05-01

    Gabor or plasma lenses have previously been used to focus intense beams of positive ions at energies from 10 keV to 5 MeV. It is the large electrostatic field of the non-neutral plasma in the Gabor lens which is responsible for the focusing. Focusing an ion beam with a given sign of charge in a Gabor lens requires a non-neutral plasma with the opposite sign of charge as the beam. A Gabor lens constructed at Fermilab has been used to focus a 30 keV proton beam with good optical quality. We discuss studies of the action of a Gabor lens on a beam of negative ions. A Gabor lens has been considered for matching an H/sup /minus// beam into an RFQ in the redesign of the low energy section of the Fermilab linac. 9 refs., 3 figs., 1 tab.

  19. Gabor lens focusing of a negative ion beam

    International Nuclear Information System (INIS)

    Gabor or plasma lenses have previously been used to focus intense beams of positive ions at energies from 10 keV to 5 MeV. It is the large electrostatic field of the non-neutral plasma in the Gabor lens which is responsible for the focusing. Focusing an ion beam with a given sign of charge in a Gabor lens requires a non-neutral plasma with the opposite sign of charge as the beam. A Gabor lens constructed at Fermilab has been used to focus a 30 keV proton beam with good optical quality. We discuss studies of the action of a Gabor lens on a beam of negative ions. A Gabor lens has been considered for matching an H/sup /minus// beam into an RFQ in the redesign of the low energy section of the Fermilab linac. 9 refs., 3 figs., 1 tab

  20. Status of eye lens radiation dose monitoring in European hospitals

    International Nuclear Information System (INIS)

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. (paper)

  1. Do gravitational lens galaxies have an excess of luminous substructure?

    CERN Document Server

    Nierenberg, A M; Treu, T

    2013-01-01

    Strong gravitational lensing can be used to directly measure the mass function of their satellites, thus testing one of the fundamental predictions of cold dark matter cosmological models. Given the importance of this test it is essential to ensure that galaxies acting as strong lenses have dark and luminous satellites which are representative of the overall galaxy population. We address this issue by measuring the number and spatial distribution of luminous satellites in ACS imaging around lens galaxies from the Sloan Lens Advanced Camera for Surveys (SLACS) lenses, and comparing them with the satellite population in ACS imaging of non lens galaxies selected from COSMOS, which has similar depth and resolution to the ACS images of SLACS lenses. In order to compare the samples of lens and non lens galaxies, which have intrinsically different stellar mass distributions, we measure, for the first time, the number of satellites per host as a continuous function of host stellar mass for both populations. We find t...

  2. Managing the Risks that Appear throughout the Pursuit of Clearing

    OpenAIRE

    Lucean MIHALCEA

    2012-01-01

    This paper proposes to deal with some aspects of clearing houses and the significant changes in European legislation in this field. It will also embark upon discussing the risks incurred in clearing houses in the current context of the international economic crisis-driven and how clearing houses in Romania can manage these risks mainly related to the market risk, credit risk and liquidity risk. This study will conclude with an econometric model of credit risk management that affects clearing ...

  3. Diagnosis of Thymic Clear Cell Carcinoma by Cytology

    OpenAIRE

    Lale, Seema A.; Tiscornia-Wasserman, Patricia G.; Mohamed Aziz

    2013-01-01

    Clear cell carcinoma of the thymus is a rare tumor. Few cases of clear-cell carcinoma of thymus have been documented (Truong et al., 1990 and Wolfe III et al., 1983). All these cases were diagnosed by histopathological examination of the tissue. Diagnosis of thymic clear cell carcinoma on cytology is extremely challenging. Here we report the first case of thymic clear cell carcinoma diagnosed by cytological examination of the pericardial fluid with the help of immunocytochemistry. Differentia...

  4. Clear cell mammary malignant myoepithelioma with abundant glycogens.

    OpenAIRE

    Kuwabara, H.; Uda, H

    1997-01-01

    Malignant myoepithelioma (myoepithelial carcinoma) of the breast is extremely rare. A case is reported of a 46 year old female with clear cell mammary malignant myoepithelioma that, on histological examination, was glycogen abundant clear cell carcinoma. Immunohistochemically, the clear cells showed myoepithelial differentiation--that is, they were a smooth muscle actin and S100 protein positive. This case shows that glycogen abundant clear cell carcinoma is a variant of malignant myoepitheli...

  5. Focusing properties of a square electrostatic rainbow lens doublet

    Directory of Open Access Journals (Sweden)

    Telečki Igor N.

    2015-01-01

    Full Text Available This is a study on the properties of a square electrostatic rainbow lens doublet. The said optical element consists of two square electrostatic rainbow lenses with the second lens axially rotated for 45 degrees with respect to the first one. The propagation of a proton beam with a kinetic energy of 10 keV through the doublet is in the focus of our analysis. The potential of the electrodes of both lenses is 2 kV. The electrostatic potential and the electric field components of the lens doublet are calculated using a 3-D computer code based on the method of moments. Spatial and angular distributions of protons propagating through the lens doublet, as well as the parameters defining beam quality, are investigated. As in the case of the single square electrostatic rainbow lens, the evolution of these distributions is determined by the evolution of corresponding rainbow lines, generated by the use of the theory of crystal rainbows. Our study shows that a beam core in the shape of a cusped square is formed by the spatial rainbow line that appears first. This rainbow line occurs during proton propagation through the first lens. The beam core retains the cusped square shape during the propagation through the second lens. The electrostatic field of the second lens causes the appearance of an additional spatial rainbow line, which encompasses the beam core and defines the outer border of the beam. This rainbow line constitutes the main difference between the cases of the lens doublet and a single lens. [Projekat Ministarstva nauke Republike Srbije, br. III45006

  6. Cosmic Lens Reveals Distant Galactic Violence

    Science.gov (United States)

    2008-10-01

    By cleverly unraveling the workings of a natural cosmic lens, astronomers have gained a rare glimpse of the violent assembly of a young galaxy in the early Universe. Their new picture suggests that the galaxy has collided with another, feeding a supermassive black hole and triggering a tremendous burst of star formation. Gravitational Lens Diagram Imaging a Distant Galaxy Using a Gravitational Lens CREDIT: Bill Saxton, NRAO/AUI/NSF Click on image for details and more graphics. The astronomers used the National Science Foundation's Very Large Array (VLA) radio telescope to look at a galaxy more than 12 billion light-years from Earth, seen as it was when the Universe was only about 15 percent of its current age. Between this galaxy and Earth lies another distant galaxy, so perfectly aligned along the line of sight that its gravity bends the light and radio waves from the farther object into a circle, or "Einstein Ring." This gravitational lens made it possible for the scientists to learn details of the young, distant galaxy that would have been unobtainable otherwise. "Nature provided us with a magnifying glass to peer into the workings of a nascent galaxy, providing an exciting look at the violent, messy process of building galaxies in the early history of the Universe," said Dominik Riechers, who led this project at the Max Planck Institute for Astronomy in Germany and now is a Hubble Fellow at the California Institute of Technology (Caltech). The new picture of the distant galaxy, dubbed PSS J2322+1944, shows a massive reservoir of gas, 16,000 light-years in diameter, that contains the raw material for building new stars. A supermassive black hole is voraciously eating material, and new stars are being born at the rate of nearly 700 Suns per year. By comparison, our Milky Way Galaxy produces the equivalent of about 3-4 Suns per year. The black hole appears to be near the edge, rather than at the center, of the giant gas reservoir, indicating, the astronomers say

  7. [New regulatory protein isolated from the bovine eye lens and its action on the cataract development in rat in vitro].

    Science.gov (United States)

    Krasnov, M S; Gurmizov, E P; Iamskova, V P; Gundorova, R A; Iamskov, I A

    2005-01-01

    The regulatory protein was isolated from the eye lens extract by using an early designed scheme including by means of salting-out of proteins by ammonium sulphate, isoelectrofocusing in pH gradient and electrophoresis in PAAG. A high-purity fraction of the regulatory protein was obtained. The localization of the regulatory protein in the rat-eye lens was investigated by means of primary rabbit antibodies obtained within the case study and by FITS-marked secondary antibodies. Cataractogenesis was induced, in vitro, in Wistar rat lenses through adding, to the cultivation medium, hydrogen peroxide (0.5 mM) or calcium chloride (15 mM). The regulatory protein isolated from the bovine eye lens was added alongside with damaging antibodies to the nutrition medium, concentration 10(-12) mg/ml. The lenses were cultivated for as long as 8 days at 37 degrees C. The degree of opacification of lenses was evaluated visually with the help of a lined substrate as well as by spectrophotometry. The studied protein was shown immunohistochemically to be localized in the intercellular space of the lens epithelium in the region of the basic membrane. The cataractogenesis-related research of the regulatory protein was made on rabbit eye lenses, which were cultivated as a whole for as long as 8 days in vitro. Their transparency and morphology were preserved in them in full since they were cultivated in a serum-free nutrition without admixture of any destructive agents. Opacification of lenses was induced in vitro by changing the concentration of calcium ions in the cultivation medium or through adding hydrogen peroxide to the medium. The valuations of the lens opacity degree as observed in different research series and made by visual observation well correlate with the results of spectrophotometry of lenses made after their cultivation. It can be stated that the studied regulatory protein, when added to the cultivation medium, enhances about two-fold the lens transparency versus the lenses

  8. The sloan lens acs survey. II. Stellar populations and internal structure of early-type lens galaxies

    NARCIS (Netherlands)

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

    2006-01-01

    We use HST images to derive effective radii and effective surface brightnesses of 15 early-type (E+S0) lens galaxies identified by the SLACS Survey. Our measurements are combined with stellar velocity dispersions from the SDSS database to investigate for the first time the distribution of lens galax

  9. 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®.

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

    NARCIS (Netherlands)

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

    2008-01-01

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

  11. Glycogen Rich Clear Cell Breast Carcinoma: A Case Report

    OpenAIRE

    Çınkır, Havva Yeşil; Dilek, Gülay Bilir; Demirci, Ayşe; Başal, Fatma Buğdaycı; Aydın, Kübra; Demirci, Umut; Öksüzoğlu, Berna; Alkış, Necati

    2014-01-01

    Glycogen-rich clear cell carcinoma of the breast is a rare type of breast carcinoma. Tumoral tissue is consist of intracytoplasmic glycogen-rich clear cells. We presented in here a 44-year old woman diagnosed with glycogen-rich clear cell carcinoma.

  12. Analysis of marine stratocumulus clearing events during FIRE

    Science.gov (United States)

    Kloesel, Kevin A.

    1990-01-01

    During FIRE, three major stratocumulus clearing events took place over the project region. These clearing events are analyzed using synoptic variables to determine if these clearing events can be predicted by current modeling techniques. A preliminary statistical evaluation of the correlation between satellite cloud brightness parameters and NMC global model parameters is available in Wylie, et al., 1989.

  13. 75 FR 63113 - Financial Resources Requirements for Derivatives Clearing Organizations

    Science.gov (United States)

    2010-10-14

    ... number of small entities. \\17\\ 5 U.S.C. 601 et seq. \\18\\ 47 FR 18618 (Apr. 30, 1982). \\19\\ See 66 FR..., and statement of cash flows, of the derivatives clearing organization or of its parent company; and... membership organization. Clearing members include futures commission merchants (FCMs) that clear on behalf...

  14. Gene expression profile of renal cell carcinoma clear cell type

    Directory of Open Access Journals (Sweden)

    Marcos F. Dall’Oglio

    2010-08-01

    Full Text Available PURPOSE: The determination of prognosis in patients with renal cell carcinoma (RCC is based, classically, on stage and histopathological aspects. The metastatic disease develops in one third of patients after surgery, even in localized tumors. There are few options for treating those patients, and even the new target designed drugs have shown low rates of success in controlling disease progression. Few studies used high throughput genomic analysis in renal cell carcinoma for determination of prognosis. This study is focused on the identification of gene expression signatures in tissues of low-risk, high-risk and metastatic RCC clear cell type (RCC-CCT. MATERIALS AND METHODS: We analyzed the expression of approximately 55,000 distinct transcripts using the Whole Genome microarray platform hybridized with RNA extracted from 19 patients submitted to surgery to treat RCC-CCT with different clinical outcomes. They were divided into three groups (1 low risk, characterized by pT1, Fuhrman grade 1 or 2, no microvascular invasion RCC; (2 high risk, pT2-3, Fuhrman grade 3 or 4 with, necrosis and microvascular invasion present and (3 metastatic RCC-CCT. Normal renal tissue was used as control. RESULTS: After comparison of differentially expressed genes among low-risk, high-risk and metastatic groups, we identified a group of common genes characterizing metastatic disease. Among them Interleukin-8 and Heat shock protein 70 were over-expressed in metastasis and validated by real-time polymerase chain reaction. CONCLUSION: These findings can be used as a starting point to generate molecular markers of RCC-CCT as well as a target for the development of innovative therapies.

  15. Evaluation of resources for contact lens practice in private contact lens clinics of Muscat, Oman

    OpenAIRE

    Rajiv Khandekar; Mohammed Al Fahdi

    2009-01-01

    Background: The integration of the contact lens (CL) practice with the VISION 2020 initiative is important. We assessed the facilities at the private CL clinics of Muscat. Accordingly, we suggested the appropriate eye care for CL wearers in Oman. Study Design: This was a descriptive study. Materials and Methods: This study was conducted between May and July 2006. A team of optometrists and health inspectors visited clinics and collected information about the infrastructure, available hu...

  16. Achromatic Metasurface Lens at Telecommunication Wavelengths.

    Science.gov (United States)

    Khorasaninejad, Mohammadreza; Aieta, Francesco; Kanhaiya, Pritpal; Kats, Mikhail A; Genevet, Patrice; Rousso, David; Capasso, Federico

    2015-08-12

    Nanoscale optical resonators enable a new class of flat optical components called metasurfaces. This approach has been used to demonstrate functionalities such as focusing free of monochromatic aberrations (i.e., spherical and coma), anomalous reflection, and large circular dichroism. Recently, dielectric metasurfaces that compensate the phase dispersion responsible for chromatic aberrations have been demonstrated. Here, we utilize an aperiodic array of coupled dielectric nanoresonators to demonstrate a multiwavelength achromatic lens. The focal length remains unchanged for three wavelengths in the near-infrared region (1300, 1550, and 1800 nm). Experimental results are in agreement with full-wave simulations. Our findings are an essential step toward a realization of broadband flat optical elements. PMID:26168329

  17. Ulcerative keratitis associated with contact lens wear

    Directory of Open Access Journals (Sweden)

    Bharathi M

    2007-01-01

    Full Text Available To review the microbiological profile of ulcerative keratitis associated with contact lens (CL-wear, 35 patients with culture-proven CL-associated microbial keratitis were studied between September 1999 and September 2002. Corneal scrapes and CL-care products were collected and were subjected to microbiological evaluation. Gram-negative bacilli alone were recovered from the corneal scrapes of all 35 (100% patients, all 70 (100% CL storage case wells and also from CL-care solution of six (17.14% of the 35 patients. There was a significantly higher number of Pseudomonas aeruginosa (71.43% isolated from eyes with CL-related keratitis than other bacterial isolates (28.57% ( P < 0.001. Microbial contamination of CL storage cases was a great risk for gram-negative bacterial infection among soft CL-wearers.

  18. The correction of electron lens aberrations.

    Science.gov (United States)

    Hawkes, P W

    2015-09-01

    The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague. PMID:26025209

  19. Ulcerative keratitis associated with contact lens wear.

    Science.gov (United States)

    Bharathi, M Jayahar; Ramakrishnan, R; Meenakshi, R; Kumar, C Shiv; Padmavathy, S; Mittal, S

    2007-01-01

    To review the microbiological profile of ulcerative keratitis associated with contact lens (CL)-wear, 35 patients with culture-proven CL-associated microbial keratitis were studied between September 1999 and September 2002. Corneal scrapes and CL-care products were collected and were subjected to microbiological evaluation. Gram-negative bacilli alone were recovered from the corneal scrapes of all 35 (100%) patients, all 70 (100%) CL storage case wells and also from CL-care solution of six (17.14%) of the 35 patients. There was a significantly higher number of Pseudomonas aeruginosa (71.43%) isolated from eyes with CL-related keratitis than other bacterial isolates (28.57%) (P<0.001). Microbial contamination of CL storage cases was a great risk for gram-negative bacterial infection among soft CL-wearers. PMID:17189892

  20. Actual Stationary State for Plasma Lens

    CERN Document Server

    Zadorozhny, Vladimir F; Parsa, Zohreh

    2005-01-01

    The electrostatic plasma lens (PL) provides an attractive and unique tool for manipulating high-current heavy ion beams. The fundamental concept of the PL is based on the use of magnetically insulated electrons and equipotentialization of magnetic field lines. Rigorous application of PL is, however, limited. The reason is the estimation behaviour of electrons for complicated magnetic fields runs into severe difficults.We show that there are specific conditions that admit steady-state of a longitudinal motion, and consider a question of it stability. These results are needed to develop an optimized PL with minimal spherical aberation, in party by optimization of the magnetic field conficuration in the low-magnetic-field range.

  1. Modulating permanent sextupole triple magnet lens

    International Nuclear Information System (INIS)

    We are developing a permanent magnet sextupole lens (PMSx) that can focus pulsed neutron. It is based on the extended Halbach configuration to generate stronger magnetic field. In order to modulate the strength of magnetic field, the magnet is divided into nested rings, where the inner ring is fixed and outer ring can be rotated. Synchronizing the phase of the modulation with time-of-flight of pulsed neutron beam suppresses the chromatic aberration. This device can focus very cold neutron (VCN) with wavelength from 2.7 to 5.5 nm at a focal length of about 1m. In triple-magnet model, the operation performance has been upgraded. A torque canceling system using permanent magnet is installed to reduce the motor load. In addition, a cooling fan for magnetic pole and neutron flight path filled with helium are installed. (author)

  2. CERN through the lens of Peter Ginter

    CERN Multimedia

    2008-01-01

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

  3. UM 425 - A new gravitational lens candidate

    International Nuclear Information System (INIS)

    The discovery of a probable gravitational lens associated with the quasar UM 425 = QSO 1120+019 is reported. BVR images of the object were obtained with a CCD using a 1.5-m telescope in March, 1987. Three close companions were observed around the bright image of the quasar. Follow-up spectroscopy suggests that the brightest companion has the same emission lines as the quasar. The velocity difference between the two brightest components from the cross-correlation technique is shown to be 200 + or - 100 km/s and is consistent with zero. Subtracting a scaled spectrum of the brighter component from the brightest companion leaves a residual which is interpreted as the spectrum of a lensing galaxy at a redshift of about 0.6. 18 refs

  4. Prototype color field sequential television lens assembly

    Science.gov (United States)

    1974-01-01

    The design, development, and evaluation of a prototype modular lens assembly with a self-contained field sequential color wheel is presented. The design of a color wheel of maximum efficiency, the selection of spectral filters, and the design of a quiet, efficient wheel drive system are included. Design tradeoffs considered for each aspect of the modular assembly are discussed. Emphasis is placed on achieving a design which can be attached directly to an unmodified camera, thus permitting use of the assembly in evaluating various candidate camera and sensor designs. A technique is described which permits maintaining high optical efficiency with an unmodified camera. A motor synchronization system is developed which requires only the vertical synchronization signal as a reference frequency input. Equations and tradeoff curves are developed to permit optimizing the filter wheel aperture shapes for a variety of different design conditions.

  5. Motherhood transition through an existential lens

    DEFF Research Database (Denmark)

    Prinds, Christina Lange

    2015-01-01

    Motherhood transition is a significant life event. Research from various disciplines outlines pregnancy, birth and the initial period of motherhood as a period of life in which a woman might experience disruption and gain new perspectives in a bodily, psychological, social and existential way. This...... research about the significance of motherhood transition through the lens of existential psychology. For the second and third study, a nationwide questionnaire survey among Danish first-time FT and PT mothers was conducted. In the second study attitudes about making meaning of life existentially was...... may be even more relevant for women giving birth preterm, since research suggests that mothers of premature babies undergo an experience of loss, crisis and unpredictability. This PhD project aimed to identify whether motherhood transition actualises considerations on how to make meaning of life...

  6. Quantum Weighted Projective and Lens Spaces

    Science.gov (United States)

    D'Andrea, Francesco; Landi, Giovanni

    2015-11-01

    We generalize to quantum weighted projective spaces in any dimension previous results of us on K-theory and K-homology of quantum projective spaces `tout court'. For a class of such spaces, we explicitly construct families of Fredholm modules, both bounded and unbounded (that is, spectral triples), and prove that they are linearly independent in the K-homology of the corresponding C *-algebra. We also show that the quantum weighted projective spaces are base spaces of quantum principal circle bundles whose total spaces are quantum lens spaces. We construct finitely generated projective modules associated with the principal bundles and pair them with the Fredholm modules, thus proving their non-triviality.

  7. Intraocular lens employed for cataract surgery

    Science.gov (United States)

    Roszkowska, A. M.; Torrisi, L.

    2014-04-01

    The aim of this paper is to illustrate the techniques of cataract surgery with implantation of intraocular lenses and some physical properties of the used materials. The new technology, coupled with extensive experience and the studied cases, permits to increase the standardization and accuracy of the engravings, by reducing the use and handling of surgical instruments inside the eye. At present it is possible to replace the cataract with crystalline lenses based on biopolymers such as PMMA, silicone, acrylic hydrophilic and hydrophobic acrylic. These materials are increasingly able to replace the natural lens and to ensure the fully functional of the eye. The role of femtosecond lasers in cataract surgery, to assist or replace several aspects of the manual cataract surgery, are discussed.

  8. Intraocular lens employed for cataract surgery

    International Nuclear Information System (INIS)

    The aim of this paper is to illustrate the techniques of cataract surgery with implantation of intraocular lenses and some physical properties of the used materials. The new technology, coupled with extensive experience and the studied cases, permits to increase the standardization and accuracy of the engravings, by reducing the use and handling of surgical instruments inside the eye. At present it is possible to replace the cataract with crystalline lenses based on biopolymers such as PMMA, silicone, acrylic hydrophilic and hydrophobic acrylic. These materials are increasingly able to replace the natural lens and to ensure the fully functional of the eye. The role of femtosecond lasers in cataract surgery, to assist or replace several aspects of the manual cataract surgery, are discussed.

  9. Tooth extraction

    Science.gov (United States)

    A tooth extraction is a procedure to remove a tooth from the gum socket. It is usually done by a general ... gum. If you need a more complex tooth extraction: You will be given sedation so you are ...

  10. Conduta cirúrgica na subluxação do cristalino Surgical approach to the subluxated lens

    Directory of Open Access Journals (Sweden)

    Nórton Souto Severo

    2004-02-01

    Full Text Available OBJETIVO: Apresentar 10 casos de subluxação de cristalino, secundários a trauma ou a síndrome de Marfan, discutindo o tratamento e os resultados obtidos. MÉTODOS: Foram estudados 10 olhos de 9 pacientes, 6 casos secundários a trauma contuso e 4 casos a síndrome de Marfan. A idade média foi de 48,9 ± 18,2 anos, com tempo de seguimento de 34,6 ± 11,6 meses (12 a 62 meses. Os pacientes foram submetidos à facectomia intracapsular (1 caso, extracapsular com capsulorrexe (1 caso, facoemulsificação sem LIO (1 caso, e facoemulsificação com implante de LIO (7 casos. Anéis expansores capsulares foram utilizados em 7 olhos. RESULTADOS: Houve melhora da acuidade visual em todos os casos durante o seguimento, exceto em um, em que houve descolamento de retina, 20 dias após o procedimento. CONCLUSÃO: A facectomia com implante de LIO em pacientes com cristalino subluxado é procedimento viável, principalmente com a facoemulsificação e o uso do anel expansor capsular, podendo melhorar bastante a acuidade visual e a qualidade de vida desses pacientes.PURPOSE: To evaluate 10 cases of subluxated lens due to trauma or Marfan syndrome, focussing on their treatment and the results. METHODS: Ten eyes of 9 patients were operated on due to lens subluxation. Six eyes were due to trauma and 4 eyes to Marfan syndrome. The mean age was 48.9 ± 18.2 years, and the follow-up period of 34.6 ± 11.6 months. Patients were submitted to intracapsular lens extraction (1 eye, extracapsular lens extraction (1 eye, phacoemulsification without IOL (1 eye, and phacoemulsification with IOL (7 eyes. Endocapsular rings were used in 7 eyes. RESULTS: Best-corrected visual acuity improved in all patients, except for one, who had a regmatogeneous retinal detachment, 20 days after surgery. CONCLUSION: Lens extraction with IOL implantation in subluxated lens patients has a good prognosis, especially with pha-coemulsification and endocapsular rings. With this approach, we were

  11. Solar lens mission concept for interstellar exploration

    Science.gov (United States)

    Brashears, Travis; Lubin, Philip; Turyshev, Slava; Shao, Michael; Zhang, Qicheng

    2015-09-01

    The long standing approach to space travel has been to incorporate massive on-board electronics, probes and propellants to achieve space exploration. This approach has led to many great achievements in science, but will never help to explore the interstellar medium. Fortunately, a paradigm shift is upon us in how a spacecraft is constructed and propelled. This paper describes a mission concept to get to our Sun's Gravity Lens at 550AU in less than 10 years. It will be done by using DE-STAR, a scalable solar-powered phased-array laser in Earth Orbit, as a directed energy photon drive of low-mass wafersats. [1] [2] [3] [4] [5] With recent technologies a complete mission can be placed on a wafer including, power from an embedded radio nuclear thermal generator (RTG), PV, laser communications, imaging, photon thrusters for attitude control and other sensors. As one example, a futuristic 200 MW laser array consisting of 1 - 10 kw meter scale sub elements with a 100m baseline can propel a 10 gram wafer scale spacecraft with a 3m laser sail to 60AU/Year. Directed energy propulsion of low-mass spacecraft gives us an opportunity to capture images of Alpha Centauri and its planets, detailed imaging of the cosmic microwave background, set up interstellar communications by using gravity lenses around nearby stars to boost signals from interstellar probes, and much more. This system offers a very large range of missions allowing hundreds of wafer scale payload launches per day to reach this cosmological data reservoir. Directed Energy Propulsion is the only current technology that can provide a near-term path to utilize our Sun's Gravity Lens.

  12. Aldose reductase inhibitory activity and antioxidant capacity of pomegranate extracts

    OpenAIRE

    Karasu, Çimen; CUMAOĞLU, Ahmet; Gürpinar, Ali Rifat; Kartal, Murat; Kovacikova, Lucia; Milackova, Ivana; Stefek, Milan

    2012-01-01

    The pomegranate, Punica granatum L., has been the subject of current interest as a medicinal agent with wide-ranging therapeutic indications. In the present study, pomegranate ethanolic seed and hull extracts were tested, in comparison with a commercial sample, for the inhibition of aldose reductase, an enzyme involved in the etiology of diabetic complications. In vitro inhibition of rat lens aldose reductase was determined by a conventional method. Pomegranate ethanolic hull extract and comm...

  13. Evaluation of Complications of Extracapsular Cataract Extraction Performed by Trainees

    OpenAIRE

    Ezegwui, IR; Aghaji, AE; Okpala, NE; Onwasigwe, EN

    2014-01-01

    Background: Cataract extraction is the most common intraocular surgery taught to residents. Aim: This study aims to review the complications of trainee-performed extracapsular cataract extraction (ECCE) so as to identify the steps in which the trainee can benefit from closer supervision and practice. Subjects and Methods: This was a descriptive retrospective study of complications in the initial 150 ECCE with intraocular lens implant performed by two Ophthalmologists, from the University of N...

  14. Effect of cataract extraction on the pupil response to mydriatics.

    OpenAIRE

    Gibbens, M V; Goel, R.; Smith, S E

    1989-01-01

    Pupil diameters in the dark, in the light, and after mydriasis with tropicamide+ phenylephrine have been measured in 25 patients before and six months after cataract surgery. The aphakic pupil showed reduced mobility as evidenced by a smaller diameter in the and a larger one in the light. In patients who had intracapsular extraction or extracapsular extraction with intraocular lens implantation the pupils dilated less well than preoperatively. The difference in response to mydriatics is of pr...

  15. Finite Element Analysis of the LOLA Receiver Telescope Lens

    Science.gov (United States)

    Matzinger, Elizabeth

    2007-01-01

    This paper presents the finite element stress and distortion analysis completed on the Receiver Telescope lens of the Lunar Orbiter Laser Altimeter (LOLA). LOLA is one of six instruments on the Lunar Reconnaissance Orbiter (LRO), scheduled to launch in 2008. LOLA's main objective is to produce a high-resolution global lunar topographic model to aid in safe landings and enhance surface mobility in future exploration missions. The Receiver Telescope captures the laser pulses transmitted through a diffractive optical element (DOE) and reflected off the lunar surface. The largest lens of the Receiver Telescope, Lens 1, is a 150 mm diameter aspheric lens originally designed to be made of BK7 glass. The finite element model of the Receiver Telescope Lens 1 is comprised of solid elements and constrained in a manner consistent with the behavior of the mounting configuration of the Receiver Telescope tube. Twenty-one temperature load cases were mapped to the nodes based on thermal analysis completed by LOLA's lead thermal analyst, and loads were applied to simulate the preload applied from the ring flexure. The thermal environment of the baseline design (uncoated BK7 lens with no baffle) produces large radial and axial gradients in the lens. These large gradients create internal stresses that may lead to part failure, as well as significant bending that degrades optical performance. The high stresses and large distortions shown in the analysis precipitated a design change from BK7 glass to sapphire.

  16. Focusing properties of a square electrostatic rainbow lens

    International Nuclear Information System (INIS)

    This paper is devoted to the focusing properties of a square electrostatic rainbow lens, which is a novel ion beam optical element. We consider the transmission of parallel and non-parallel proton beams of the initial kinetic energy of 10 keV through this lens. The potential of the electrodes of the lens is chosen to be 2 kV. The electrostatic potential and components of the electric field in the region of the lens are calculated using a three-dimensional finite element computer code. We investigate the spatial and angular distributions of protons propagating through the lens and in the drift space after it. It is confirmed that the evolutions of these distributions are determined by the evolutions of the corresponding rainbow lines, generated using the theory of crystal rainbows. The beam is separated into two components. One beam component, appearing as a beam core, is generated dominantly by the focused protons. Its boundary line in the transverse position plane can be very well approximated by a hypotrochoid. The other beam component is generated dominantly by the defocused protons. We present the focusing coefficient of the lens, the confining coefficients of the lens for the focused and defocused protons, the density of the beam core, the vertical or horizontal emittance of the beam core, and the brightness of the beam core.

  17. Challenges of using dielectric elastomer actuators to tune liquid lens

    Science.gov (United States)

    Keong, Gih-Keong; La, Thanh-Giang; Shiau, Li-Lynn; Tan, Adrian W. Y.

    2014-03-01

    Recently, dielectric elastomer actuators (DEAs) have been adopted to tune liquid membrane lens, just like ciliary muscles do to the lens in human eye. However, it faces some challenges, such as high stress, membrane puncture, high driving voltage requirement, and limited focus distance (not more than 707cm), that limit its practical use. The design problem gets more complex as the liquid lens shares the same elastomeric membrane as the DEA. To address these challenges, we separate DEA from the lens membrane. Instead, a liquid-immersed DEA, which is safe from terminal failure, is used as a diaphragm pump to inflate or deflate the liquid lens by hydraulic pressure. This opens up the possibility that the DEA can be thinned down and stacked up to reduce the driving voltage, independent of the lens membrane thickness. Preliminary study showed that our 8-mm-diameter tunable lens can focus objects in the range of 15cm to 50cm with a small driving voltage of 1.8kV. Further miniaturization of DEA could achieve a driving voltage less than 1kV.

  18. LASL lens design procedure: simple, fast, precise, versatile

    Energy Technology Data Exchange (ETDEWEB)

    Brixner, B.

    1978-11-01

    The Los Alamos Scientific Laboratory general-purpose lens design procedure optimizes specific lens prescriptions to obtain the smallest possible image spots and therefore near-spherical wave fronts of light converging on all images in the field of view. Optical image errors are analyzed in much the same way that they are measured on the optical bench. This lens design method is made possible by using the full capabilities of large electronic computers. First, the performance of the whole lens is sampled with many precisely traced skew rays. Next, lens performance is analyzed with spot diagrams generated by the many rays. Third, lens performance is optimized with a least squares system aimed at reducing all image errors to zero. This statistical approach to lens design uses skew rays and precisely measured ray deviations from ideal image points to achieve greater accuracy than was possible with the classical procedure, which is based on approximate expressions derived from simplified ray traces developed for pencil-and-paper calculations.

  19. Numerical implementation of generalized Coddington equations for ophthalmic lens design

    Science.gov (United States)

    Rojo, P.; Royo, S.; Ramírez, J.; Madariaga, I.

    2014-02-01

    A method for general implementation in any software platform of the generalized Coddington equations is presented, developed, and validated within a Matlab environment. The ophthalmic lens design strategy is presented thoroughly, and the basic concepts of generalized ray tracing are introduced. The methodology for ray tracing is shown to include two inter-related processes. Firstly, finite ray tracing is used to provide the main direction of propagation of the considered ray at the incidence point of interest. Afterwards, generalized ray tracing provides the principal curvatures of the local wavefront at that point, and its orientation after being refracted by the lens. The curvature values of the local wavefront are interpreted as the sagital and tangential powers of the lens at the point of interest. The proposed approach is validated using a double-check of the calculated lens performance in the spherical lens case: while finite ray tracing is validated using a commercial ray tracing software, generalized ray tracing is validated using a software application for ophthalmic lens design based on the classical version of Coddington equations. Equations of the complete tracing process are developed in detail for the case of generic astigmatic ophthalmic lenses as an example. Three-dimensional representation of the sagital and tangential powers of the ophthalmic lens at all directions of gaze then becomes possible, and results are presented for lenses with different geometries.

  20. Critical Assessment of Correction Methods for Fisheye Lens Distortion

    Science.gov (United States)

    Liu, Y.; Tian, C.; Huang, Y.

    2016-06-01

    A fisheye lens is widely used to create a wide panoramic or hemispherical image. It is an ultra wide-angle lens that produces strong visual distortion. The distortion modeling and estimation of the fisheye lens are the crucial step for fisheye lens calibration and image rectification in computer vision and close-range photography. There are two kinds of distortion: radial and tangential distortion. Radial distortion is large for fisheye imaging and critical for the subsequent image processing. Although many researchers have developed calibration algorithms of radial distortion of fisheye lens, quantitative evaluation of the correction performance has remained a challenge. This is the first paper that intuitively and objectively evaluates the performance of five different calibration algorithms. Upto- date research on fisheye lens calibration is comprehensively reviewed to identify the research need. To differentiate their performance in terms of precision and ease-using, five methods are then tested using a diverse set of actual images of the checkerboard that are taken at Wuhan University, China under varying lighting conditions, shadows, and shooting angles. The method of rational function model, which was generally used for wide-angle lens correction, outperforms the other methods. However, the one parameter division model is easy for practical use without compromising too much the precision. The reason is that it depends on the linear structure in the image and requires no preceding calibration. It is a tradeoff between correction precision and ease-using. By critically assessing the strengths and limitations of the existing algorithms, the paper provides valuable insight and guideline for future practice and algorithm development that are important for fisheye lens calibration. It is promising for the optimal design of lens correction models that are suitable for the millions of portable imaging devices.