WorldWideScience

Sample records for lens nuclei increased

  1. Porcine lens nuclei as a model for comparison of 3 ultrasound modalities regarding efficiency and chatter.

    Science.gov (United States)

    Oakey, Zack B; Jensen, Jason D; Zaugg, Brian E; Radmall, Bryce R; Pettey, Jeff H; Olson, Randall J

    2013-08-01

    To validate a porcine lens model by comparing density and ultrasound (US) with known human standards using the Infiniti Ozil with Intelligent Phacoemulsification (torsional), Whitestar Signature Micropulse (longitudinal), and Ellips FX (transversal) modalities. Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Lens nuclei were formalin soaked in hour-based intervals and divided into 2.0 mm cubes. Density was characterized by crushing experiments and compared with known human measures. Efficiency and chatter were examined. The mean weight to cut thickness in half ranged from 16.9 g ± 5.5 (SD) in the 0-hour group to 121.3 ± 47.5 gm in the 4-hour group. Lenses in the 2-hour group (mean 70.2 ± 19.1 g) best matched human density (P=.215). The mean efficiency ranged from 0.432 ± 0.178 seconds to 9.111 ± 2.925 seconds; chatter ranged from zero to 1.85 ± 1.927 bounces. No significant difference was detected when comparing the 2-hour formalin group with human lenses in torsional and transversal US. There was no significant difference between transversal and torsional modalities, consistent with human studies. Although longitudinal (6 milliseconds on, 12 milliseconds off) was significantly more efficient at 50% power than at 25%, there was no significant difference compared with transversal or torsional US. Animal lenses soaked for 2 hours in formalin were most comparable to human lenses. Longitudinal US may be an acceptable alternative to torsional and transversal US. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  2. Increased ionization supports growth of aerosols into cloud condensation nuclei

    DEFF Research Database (Denmark)

    Svensmark, H.; Enghoff, M. B.; Shaviv, N. J.

    2017-01-01

    Ions produced by cosmic rays have been thought to influence aerosols and clouds. In this study, the effect of ionization on the growth of aerosols into cloud condensation nuclei is investigated theoretically and experimentally. We show that the mass-flux of small ions can constitute an important...... and find good agreement with theory. Ion-induced condensation should be of importance not just in Earth’s present day atmosphere for the growth of aerosols into cloud condensation nuclei under pristine marine conditions, but also under elevated atmospheric ionization caused by increased supernova activity....

  3. Aspartic acid racemization rate in narwhal (Monodon monoceros) eye lens nuclei estimated by counting of growth layers in tusks

    DEFF Research Database (Denmark)

    Garde, Eva; Heide-Jørgensen, Mads Peter; Ditlevsen, Susanne

    2012-01-01

    Ages of marine mammals have traditionally been estimated by counting dentinal growth layers in teeth. However, this method is difficult to use on narwhals (Monodon monoceros) because of their special tooth structures. Alternative methods are therefore needed. The aspartic acid racemization (AAR......) technique has been used in age estimation studies of cetaceans, including narwhals. The purpose of this study was to estimate a species-specific racemization rate for narwhals by regressing aspartic acid D/L ratios in eye lens nuclei against growth layer groups in tusks (n=9). Two racemization rates were...

  4. Lens autofluorescence is not increased at high altitude

    DEFF Research Database (Denmark)

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

    2010-01-01

    in Denmark. RESULTS: No significant differences in lens fluorescence or transmittance were found between Bolivian and Danish volunteers. CONCLUSION: Age-corrected lens fluorescence and transmittance were comparable for healthy participants living at high altitude near the equator and healthy volunteers...

  5. nuclei

    Directory of Open Access Journals (Sweden)

    Minkov N.

    2016-01-01

    Full Text Available We study the effects of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even heavy and superheavy nuclei. The neutron two-quasiparticle (2qp isomeric energies and magnetic dipole moments are calculated within a deformed shell model with the Bardeen-Cooper- Schrieffer (BCS pairing interaction over a wide range of quadrupole and octupole deformations. We found that in most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation, while the 2qp energies indicate regions of nuclei in which the presence of high-K isomeric states may be associated with the presence of octupole softness or even with octupole deformation. In the present work we also examine the influence of the BCS pairing strength on the energy of the blocked isomer configuration. We show that the formation of 2qp energy minima in the space of quadrupole-octupole and eventually higher multipolarity deformations is a subtle effect depending on nuclear pairing correlations.

  6. Increased resistance of contact lens related bacterial biofilms to antimicrobial activity of soft contact lens care solutions

    Science.gov (United States)

    Szczotka-Flynn, Loretta B.; Imamura, Yoshifumi; Chandra, Jyotsna; Yu, Changping; Mukherjee, Pranab K.; Pearlman, Eric; Ghannoum, Mahmoud A.

    2014-01-01

    PURPOSE To determine if clinical and reference strains of Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus aureus form biofilms on silicone hydrogel contact lenses, and ascertain antimicrobial activities of contact lens care solutions. METHODS Clinical and American Type Culture Collection (ATCC) reference strains of Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus aureus were incubated with lotrafilcon A lenses under conditions that facilitate biofilm formation. Biofilms were quantified by quantitative culturing (colony forming units, CFUs), and gross morphology and architecture were evaluated using scanning electron microscopy (SEM) and confocal microscopy. Susceptibilities of the planktonic and biofilm growth phases of the bacteria to five common multipurpose contact lens care solutions and one hydrogen peroxide care solution were assessed. RESULTS P. aeruginosa, S. marcescens, and S. aureus reference and clinical strains formed biofilms on lotrafilcon A silicone hydrogel contact lenses, as dense networks of cells arranged in multiple layers with visible extracellular matrix. The biofilms were resistant to commonly used biguanide preserved multipurpose care solutions. P. aeruginosa and S. aureus biofilms were susceptible to a hydrogen peroxide and a polyquaternium preserved care solution, whereas S. marcescens biofilm was resistant to a polyquaternium preserved care solution but susceptible to hydrogen peroxide disinfection. In contrast, the planktonic forms were always susceptible. CONCLUSIONS P. aeruginosa, S. marcescens, and S. aureus form biofilms on lotrafilcon A contact lenses, which in contrast to planktonic cells, are resistant to the antimicrobial activity of several soft contact lens care products. PMID:19654521

  7. Diquafosol Ophthalmic Solution Increases Pre- and Postlens Tear Film During Contact Lens Wear in Rabbit Eyes.

    Science.gov (United States)

    Nagahara, Yukiko; Koh, Shizuka; Oshita, Yoshihiro; Nagano, Takashi; Mano, Hidetoshi; Nishida, Kohji; Watanabe, Hitoshi

    2017-11-01

    To investigate the behavior of prelens tear film (PLTF) and postlens tear film (PoLTF) after the instillation of diquafosol using an experimental rabbit model of eyes with contact lens. Cross-sectional, anterior segment optical coherence tomographic images of the inferior midperipheral cornea were obtained at baseline and at 5, 15, 30, 60, 90, and 120 min after the instillation of 3% diquafosol ophthalmic solution in 10 Japanese white rabbits wearing contact lenses. From the obtained images, the areas of the PLTF and PoLTF were calculated. Both artificial tear solution and 0.1% sodium hyaluronate ophthalmic solution were used for comparison. Significant fluid accumulation in both the PLTF and PoLTF was observed after diquafosol instillation, whereas no fluid accumulation was visible after the instillation of artificial tear or sodium hyaluronate. The increase in PLTF area after diquafosol instillation was significantly higher (Pophthalmic solution increases PLTF and PoLTF in rabbit eyes with contact lenses. Diquafosol has potential as a treatment option for contact lens-related dry eye.

  8. Winter sowing of adapted lines as a potential yield increase strategy in lentil (Lens culinaris Medik.

    Directory of Open Access Journals (Sweden)

    Abel Barrios

    2016-06-01

    Full Text Available Lentil (Lens culinaris Medik. subsp. culinaris is a traditional crop in Spain although current grain yield in Spain is relatively low and unstable. The effect of an early sowing date (winter sowing on yield in the Spanish Central Plateau (meseta was analyzed comparing it to the traditional spring sowing. Yield from eleven cultivars currently available for sowing in Spain and two F6:7  populations of recombinant inbred lines (RIL, ´Precoz´ × ´WA8649041´ (89 lines and ´BGE016365´ × ´ILL1918´ (118 lines, was evaluated in winter and spring sowing dates for three seasons (2005/06, 2006/07 and 2007/08 and two localities. Yield and stability were assessed by the method of consistency of performance with some modifications. When comparing with the best currently available cultivars sown in the traditional spring sowing date, (with an estimated average yield of 43.9 g/m in our experimental conditions, winter sowing using adapted breeding lines proved to be a suitable strategy for increasing lentil yield and yield stability in the Spanish meseta, with an average yield increase of 111% (reaching an estimated yield of 92.8 g/m. Results point to that lentil production can greatly increase in the Spanish meseta if adequate plant materials, such as some of the lines analyzed, are sown at late fall.

  9. Winter sowing of adapted lines as a potential yield increase strategy in lentil (Lens culinaris Medik.)

    Energy Technology Data Exchange (ETDEWEB)

    Barrios, A.; Aparicio, T.; Rodríguez, M.J.; Pérez de la Vega, M.; Caminero, C.

    2016-11-01

    Lentil (Lens culinaris Medik. subsp. culinaris) is a traditional crop in Spain although current grain yield in Spain is relatively low and unstable. The effect of an early sowing date (winter sowing) on yield in the Spanish Central Plateau (meseta) was analyzed comparing it to the traditional spring sowing. Yield from eleven cultivars currently available for sowing in Spain and two F6:7 populations of recombinant inbred lines (RIL), ´Precoz´ × ´WA8649041´ (89 lines) and ´BGE016365´ × ´ILL1918´ (118 lines), was evaluated in winter and spring sowing dates for three seasons (2005/06, 2006/07 and 2007/08) and two localities. Yield and stability were assessed by the method of consistency of performance with some modifications. When comparing with the best currently available cultivars sown in the traditional spring sowing date, (with an estimated average yield of 43.9 g/m in our experimental conditions), winter sowing using adapted breeding lines proved to be a suitable strategy for increasing lentil yield and yield stability in the Spanish meseta, with an average yield increase of 111% (reaching an estimated yield of 92.8 g/m). Results point to that lentil production can greatly increase in the Spanish meseta if adequate plant materials, such as some of the lines analyzed, are sown at late fall. (Author)

  10. Increasing the field-of-view of row–column-addressed ultrasound transducers: implementation of a diverging compound lens

    DEFF Research Database (Denmark)

    Engholm, Mathias; Beers, Christopher; Bouzari, Hamed

    2018-01-01

    was fabricated of a Bi2O3 loaded RTV615 and an unloaded Hapflex 541. The lens was tested using a RCA probe, and a FOV of 32.2° was measured from water tank tests, while the FEM model yielded 33.4°. A wire phantom with 0.15 mm diameter wires was imaged at 3 MHz down to a depth of 14 cm using a synthetic aperture...... imaging sequence with single element transmissions. The beamformed image showed that wires outside the array footprint were visible, demonstrating the increased FOV....

  11. Superdeformed nuclei

    International Nuclear Information System (INIS)

    Janssens, R.V.F.; Khoo, T.L.

    1991-01-01

    Superdeformation was first proposed some twenty years ago to explain the fission isomers observed in some actinide nuclei. It was later realized that superdeformed shapes can occur at high angular momentum in lighter nuclei. The interest in the mechanisms responsible for these exotic shapes has increased enormously with the discovery of a superdeformed band of nineteen discrete lines in 152 Dy (8). At about the same time, evidence for highly deformed nuclei (axis ratio 3:2) was also reported near 132 Ce(9). Striking properties emerged from the first experiments, such as the essentially constant energy spacing between transitions (picket-fence spectra), the unexpectedly strong population of superdeformed bands at high spins, and the apparent lack of a link between the superdeformed states and the yrast levels. These findings were reviewed by Nolan and Twin. The present article follows upon their work and discusses the wealth of information that has since become available. This includes the discovery of a new island of superdeformation near A = 190, the detailed spectroscopy of ground and excited bands in the superdeformed well near A = 150 and A = 190, the surprising occurrence of superdeformed bands with identical transition energies in nuclei differing by one or two mass units, and the improved understanding of mechanisms responsible for the feeding into and the decay out of the superdeformed states

  12. BIX-01294 increases pig cloning efficiency by improving epigenetic reprogramming of somatic cell nuclei.

    Science.gov (United States)

    Huang, Jiaojiao; Zhang, Hongyong; Yao, Jing; Qin, Guosong; Wang, Feng; Wang, Xianlong; Luo, Ailing; Zheng, Qiantao; Cao, Chunwei; Zhao, Jianguo

    2016-01-01

    Accumulating evidence suggests that faulty epigenetic reprogramming leads to the abnormal development of cloned embryos and results in the low success rates observed in all mammals produced through somatic cell nuclear transfer (SCNT). The aberrant methylation status of H3K9me and H3K9me2 has been reported in cloned mouse embryos. To explore the role of H3K9me2 and H3K9me in the porcine somatic cell nuclear reprogramming, BIX-01294, known as a specific inhibitor of G9A (histone-lysine methyltransferase of H3K9), was used to treat the nuclear-transferred (NT) oocytes for 14-16 h after activation. The results showed that the developmental competence of porcine SCNT embryos was significantly enhanced both in vitro (blastocyst rate 16.4% vs 23.2%, Pcloning rate 1.59% vs 2.96%) after 50 nm BIX-01294 treatment. BIX-01294 treatment significantly decreased the levels of H3K9me2 and H3K9me at the 2- and 4-cell stages, which are associated with embryo genetic activation, and increased the transcriptional expression of the pluripotency genes SOX2, NANOG and OCT4 in cloned blastocysts. Furthermore, the histone acetylation levels of H3K9, H4K8 and H4K12 in cloned embryos were decreased after BIX-01294 treatment. However, co-treatment of activated NT oocytes with BIX-01294 and Scriptaid rescued donor nuclear chromatin from decreased histone acetylation of H4K8 that resulted from exposure to BIX-01294 only and consequently improved the preimplantation development of SCNT embryos (blastocyst formation rates of 23.7% vs 21.5%). These results indicated that treatment with BIX-01294 enhanced the developmental competence of porcine SCNT embryos through improvements in epigenetic reprogramming and gene expression. © 2016 Society for Reproduction and Fertility.

  13. Pseudomagic nuclei

    International Nuclear Information System (INIS)

    Scharff-Goldhaber, G.

    1979-01-01

    It was shown previously that, below a critical angular momentum, yrast bands of nonmagic nuclei are well described by the two-parameter variable moment of inertia model. Some striking exceptions to this rule are found in nuclei which have the same mass number as doubly magic nuclei but possess either one (or two) proton pairs beyond a magic number and one (or two) neutron hole pairs, or vice versa. Yrast bands in these pseudomagic nuclei resemble those in magic nuclei. 17 references

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

    Directory of Open Access Journals (Sweden)

    Hong Yan

    2017-02-01

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

  15. Electromagnetic noise inhibits radiofrequency radiation-induced DNA damage and reactive oxygen species increase in human lens epithelial cells

    Science.gov (United States)

    Wu, Wei; Wang, KaiJun; Ni, Shuang; Ye, PanPan; Yu, YiBo; Ye, Juan; Sun, LiXia

    2008-01-01

    Purpose The goal of this study was to investigate whether superposing of electromagnetic noise could block or attenuate DNA damage and intracellular reactive oxygen species (ROS) increase of cultured human lens epithelial cells (HLECs) induced by acute exposure to 1.8 GHz radiofrequency field (RF) of the Global System for Mobile Communications (GSM). Methods An sXc-1800 RF exposure system was used to produce a GSM signal at 1.8 GHz (217 Hz amplitude-modulated) with the specific absorption rate (SAR) of 1, 2, 3, and 4 W/kg. After 2 h of intermittent exposure, the ROS level was assessed by the fluorescent probe, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). DNA damage to HLECs was examined by alkaline comet assay and the phosphorylated form of histone variant H2AX (γH2AX) foci formation assay. Results After exposure to 1.8 GHz RF for 2 h, HLECs exhibited significant intracellular ROS increase in the 2, 3, and 4 W/kg groups. RF radiation at the SAR of 3 W/kg and 4 W/kg could induce significant DNA damage, examined by alkaline comet assay, which was used to detect mainly single strand breaks (SSBs), while no statistical difference in double strand breaks (DSBs), evaluated by γH2AX foci, was found between RF exposure (SAR: 3 and 4 W/kg) and sham exposure groups. When RF was superposed with 2 μT electromagnetic noise could block RF-induced ROS increase and DNA damage. Conclusions DNA damage induced by 1.8 GHz radiofrequency field for 2 h, which was mainly SSBs, may be associated with the increased ROS production. Electromagnetic noise could block RF-induced ROS formation and DNA damage. PMID:18509546

  16. Applying a Total Market Lens: Increased IUD Service Delivery Through Complementary Public- and Private-Sector Interventions in 4 Countries

    Science.gov (United States)

    White, Julia N; Corker, Jamaica

    2016-01-01

    ABSTRACT Increasing access to the intrauterine device (IUD), as part of a comprehensive method mix, is a key strategy for reducing unintended pregnancy and maternal mortality in low-income countries. To expand access to IUDs within the framework of informed choice, Population Services International (PSI) has historically supported increased IUD service delivery through private providers. In applying a total market lens to better understand the family planning market and address major market gaps, PSI identified a lack of high-quality public provision of IUDs. In 2013, PSI started a pilot in 4 countries (Guatemala, Laos, Mali, and Uganda) to grow public-provider IUD service delivery through increased public-sector engagement while maintaining its ongoing focus on private providers. In collaboration with country governments, PSI affiliates carried out family planning market analyses in the 4 pilot countries to identify gaps in IUD service delivery and create sustainable strategies for scaling up IUD services in the public sector. Country-specific interventions to increase service delivery were implemented across all levels of the public health system, including targeted advocacy at the national level to promote government ownership and program sustainability. Mechanisms to ensure government ownership were built into the program design, including a proof-of-concept approach to convince governments of the feasibility and value of taking over and scaling up interventions. In the first 2 years of the pilot (2013–2014), 102,055 IUD services were provided to women at 417 targeted public-sector facilities. These preliminary results suggest that there is untapped demand for IUD service delivery in the public sector that can be met in part through greater participation of the public sector in family planning and IUD provision. PMID:27540122

  17. Applying a Total Market Lens: Increased IUD Service Delivery Through Complementary Public- and Private-Sector Interventions in 4 Countries.

    Science.gov (United States)

    White, Julia N; Corker, Jamaica

    2016-08-11

    Increasing access to the intrauterine device (IUD), as part of a comprehensive method mix, is a key strategy for reducing unintended pregnancy and maternal mortality in low-income countries. To expand access to IUDs within the framework of informed choice, Population Services International (PSI) has historically supported increased IUD service delivery through private providers. In applying a total market lens to better understand the family planning market and address major market gaps, PSI identified a lack of high-quality public provision of IUDs. In 2013, PSI started a pilot in 4 countries (Guatemala, Laos, Mali, and Uganda) to grow public-provider IUD service delivery through increased public-sector engagement while maintaining its ongoing focus on private providers. In collaboration with country governments, PSI affiliates carried out family planning market analyses in the 4 pilot countries to identify gaps in IUD service delivery and create sustainable strategies for scaling up IUD services in the public sector. Country-specific interventions to increase service delivery were implemented across all levels of the public health system, including targeted advocacy at the national level to promote government ownership and program sustainability. Mechanisms to ensure government ownership were built into the program design, including a proof-of-concept approach to convince governments of the feasibility and value of taking over and scaling up interventions. In the first 2 years of the pilot (2013-2014), 102,055 IUD services were provided to women at 417 targeted public-sector facilities. These preliminary results suggest that there is untapped demand for IUD service delivery in the public sector that can be met in part through greater participation of the public sector in family planning and IUD provision. © White et al.

  18. Effect of X-irradiation and vitamin C on DNA degradation and endogenous DNAase in embryonic chick lens cells

    International Nuclear Information System (INIS)

    Trevithick, J.R.; Chaudun, E.; Muel, A.S.; Courtois, Y.; Counis, M.F.

    1987-01-01

    The lens is an organ in which epithelial cells become elongated fibers. During this process, nuclei are transformed and the DNA is degraded. In previous studies, we described an autodigestion of the chromatin in isolated fiber nuclei but not in epithelial nuclei, but the level of DNAase activity was found to be identical in both epithelial and fiber nuclei of lenses at 11 days of development. In this study, we have investigated the possibility that x-irradiation might stimulate the nuclear endogenous activity responsible for chromatin breakdown or epithelial cells to a level comparable to that observed in fiber cells. We have observed that x-irradiation does not increase the nuclear epithelial DNAase activity. Conversely, vitamin C, suspected to prevent cataract formation by protecting DNA against free radical formation, has a damaging effect on the DNA of the lens of chick embryo in vitro. (author)

  19. Selenite and ebselen supplementation attenuates D-galactose-induced oxidative stress and increases expression of SELR and SEP15 in rat lens.

    Science.gov (United States)

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

    2016-12-01

    Selenite and ebselen supplementation has been shown to possess anti-cataract potential in some experimental animal models of cataract, however, the underlying mechanisms remain unclear. The present study was designed to evaluate the anti-cataract effects and the underlying mechanisms of selenite and ebselen supplementation on galactose induced cataract in rats, a common animal model of sugar cataract. Transmission electron microscopy images of lens fiber cells (LFC) and lens epithelial cells (LEC) were observed in D-galactose-induced experimental cataractous rats treated with or without selenite and ebselen, also redox homeostasis and expression of proteins such as selenoprotein R (SELR), 15kD selenoprotein (SEP15), superoxide dismutase 1 (SOD1), catalase (CAT), β-crystallin protein, aldose reductase (AR) and glucose-regulated protein 78 (GRP78) were estimated in the lenses. The results showed that D-galactose injection injured rat lens and resulted in cataract formation; however, selenite and ebselen supplementation markedly alleviated ultrastructural injury of LFC and LEC. Moreover, selenite and ebselen supplementation could mitigate the oxidative damage in rat lens and increase the protein expressions of SELR, SEP15, SOD1, CAT and β-crystallin, as well as decrease the protein expressions of AR and GRP78. Taken together, these findings for the first time reveal the anti-cataract potential of selenite and ebselen in galactosemic cataract, and provide important new insights into the anti-cataract mechanisms of selenite and ebselen in sugar cataract.

  20. Exotic nuclei

    International Nuclear Information System (INIS)

    Villari, A.C.C.

    1990-01-01

    The actual tendencies to study exotic nuclei; applications of exotic nuclei beams in material study and medicine; recent results obtained by GANIL and Berkeley Laboratories of measurements of binding energy and radii of light nuclei; the future experiences to be carry out in several international laboratories and; proposal of studies in Brazil using Pelletron-USP accelerator and the LINAC superconductor accelerator, in construction in the same laboratory, are presented. (M.C.K.)

  1. Disassembly of the lens fiber cell nucleus to create a clear lens: the p27 descent

    Science.gov (United States)

    The eye lens is unique among tissues: it is transparent, does not form tumors, and the majority of its cells degrade their organelles, including their cell nuclei. A mystery for over a century, there has been considerable recent progress in elucidating mechanisms of lens fiber cell denucleation (LFC...

  2. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

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

  3. Prevalence of antiseptic resistance genes increases in staphylococcal isolates from orthokeratology lens wearers over initial six-month period of use.

    Science.gov (United States)

    Guang-Sen, Shi; Boost, Maureen; Cho, Pauline

    2016-06-01

    The purpose of this study was to investigate the prevalence of antiseptic-resistance (QAC) genes in staphylococci colonizing periorbital tissues and accessories of orthokeratology (ortho-k) lens wearers over a 6-month period and determine the effect of their presence on minimum inhibitory (MIC) and bactericidal concentrations (MBC) of disinfectants and log reduction of multipurpose contact lens solutions (MPS). Staphylococci were isolated from periorbital tissues and accessories of patients before commencing ortho-k therapy and at two subsequent visits. Presence of QAC genes in 116 S. aureus and 67 CNS isolates was determined by PCR and association with period of ortho-k use determined. MICs and MBCs of staphylococci gene-positive were compared with gene-negative strains and the effectiveness of four MPS for rigid contact lenses investigated. S. aureus carriage rates in the conjunctiva decreased significantly from 41.2 % (baseline) to 11.8 % (3-months), and 13.3 % (6-months) (p trend 0.03), while CNS increased from 58.8 %(baseline) to 94.1 % (3-months), and 93.3 % (6-months) (p trend 0.02). Prevalence of qacA/B increased considerably over time (S. aureus: 4.4 % to 15.4 %, CNS: 6.7 % to 25 %), but frequency of smr was relatively stable. Only five CNS isolates harboured qacH. MICs and MBCs of gene-positive isolates were significantly increased and three MPS did not achieve a 3-log reduction of many QAC-positive strains. Ortho-k lens wear contributed to changes of staphylococcal carriage rates in the conjunctival sac. Use of MPS containing quaternary ammonium compounds may select for the carriage of organisms harbouring QAC genes, as the low concentration of disinfecting agents is not adequate for killing gene-positive strains.

  4. Structure of Warm Nuclei

    International Nuclear Information System (INIS)

    Aaberg, S.; Uhrenholt, H.

    2009-01-01

    We study the structure of nuclei in the energy region between the ground state and the neutron separation energy, here called warm nuclei. The onset of chaos in the nucleus as excitation energy is increased is briefly reviewed. Chaos implies fluctuations of energies and wave functions qualitatively the same for all chaotic nuclei. On the other hand, large structure effects are seen, e.g. in the level-density function at same excitation energies. A microscopic model for the level density is reviewed and we discuss effects on structure of the total level-density function, parity enhancement, and the spin distribution function. Comparisons to data are performed at the neutron separation energy for all observed nuclei, and structure of the level-density function for a few measured cases. The role of structure effects in the level-density function for fission dynamics is exemplified.

  5. Effects of retinal growth factor and of the increase of the number of subcultures on sulfated glycosaminoglycans of bovine lens epithelial cells

    International Nuclear Information System (INIS)

    Moczar, E.; Courtois, Y.

    1981-01-01

    Sulfated glycosaminoglycans of cultured bovine lens epithelial cells grown in the presence and in the absence of a retinal growth factor were investigated comparatively. The newly formed [ 35 S] sulfate-labeled glycosaminoglycans were analysed in the extra-, peri- and intracellular compartments of early (4-5th) and late (17-18h) subcultures. The following results were obtained: (1) Cultured lens epithelial cells grown in the presence or in the absence of the growth factor synthesize chondroitin 4- and 6-sulfates and dermatan sulfate, with heparan sulfate as the main component, the pericellular compartments were particularly rich in heparan sulfate; (2) The distribution pattern of the glycosaminoglycans changes during successive subcultures; the proportion of heparan sulfate increases in the pericellular compartment, the dermatan sulfate to chondroitin sulfate ratio increases in all three compartments; (3) In contrast to the drastic decrease in the fibronectin levels in the presence of growth factor in the early subcultures, only minor differences were found between the glycosaminoglycan patterns for the treated and non-treated cells. ( orig.)

  6. Multifragmentation of hot nuclei

    International Nuclear Information System (INIS)

    Tamain, B.

    1990-10-01

    It is difficult to deposit a large amount (∼ 1 Gev) of excitation energy into a nucleus. And if one wants to deposit large excitation energy values, the best way consists of shooting a given target nucleus with several nucleons, which can be achieved by using intermediate energy (10-100 MeV/nucleon) heavy ions. Such very excited objects were named hot nuclei. The study of hot nuclei has been undertaken only for 7 years because intermediate energy heavy ion facilities were not available before. The game is then to determine the decay properties of such nuclei, their limits of existence. Their study is connected with general properties of nuclear matter: namely its equation of state. Of special interest, is the onset of a new decay mechanism: multifragmentation, which is the non-sequential disassembly of a hot nucleus into several light nuclei (often called intermediate-mass fragments or IMF) or particles. This paper, shows how this mechanism can reflect fundamental properties of nuclear matter, but also how its experimental signature is difficult to establish. Multifragmentation has also been studied by using very energetic projectiles (protons and heavy ions) in the relativistic or ultra-relativistic region. The multifragmentation question of hot nuclei is far from being solved. One knows that IMF production increases when the excitation energy brought into a system is strongly increased, but very little is known about the mechanisms involved and a clear onset for multifragmentation is not established

  7. Colliding nuclei

    International Nuclear Information System (INIS)

    Balian, Roger; Remaud, Bernard; Suraud, E.; Durand, Dominique; Tamain, Bernard; Gobbi, A.; Cugnon, J.; Drapier, Olivier; Govaerts, Jan; Prieels, Rene

    1995-09-01

    This 14. international school Joliot-Curie of nuclear physic deals with nuclei in collision at high energy. Nine lectures are included in the proceedings of this summer school: 1 - From statistical mechanics outside equilibrium to transport equations (Balian, R.); 2 - Modeling of heavy ions reactions (Remaud, B.); 3 - Kinetic equations in heavy ions physics (Suraud, E.); 4 - Colliding nuclei near the Fermi energy (Durand, D.; Tamain, B.); 5 - From the Fermi to the relativistic energy domain: which observable? For which physics? (Gobbi, A.); 6 - Collisions at relativistic and ultra relativistic energies, Theoretical aspects (Cugnon, J.); 7 - Quark-gluon plasma: experimental signatures (Drapier, O.); 8 - Electroweak interaction: a window on physics beyond the standard model (Govaerts, J.); 9 - Symmetry tests in β nuclear process: polarization techniques (Prieels, R.)

  8. 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...

  9. Social interaction and cocaine conditioning in mice increase spontaneous spike frequency in the nucleus accumbens or septal nuclei as revealed by multielectrode array recordings.

    Science.gov (United States)

    Kummer, Kai K; El Rawas, Rana; Kress, Michaela; Saria, Alois; Zernig, Gerald

    2015-01-01

    Both cocaine and social interaction place preference conditioning lead to increased neuronal expression of the immediate early gene EGR1 in the nucleus accumbens, a central region of the reward pathway, suggesting that both drug and natural rewards may be processed in similar brain regions. In order to gain novel insights into the intrinsic in vitro electrical activity of the nucleus accumbens and adjacent brain regions and to explore the effects of reward conditioning on network activity, we performed multielectrode array recordings of spontaneous firing in acute brain slices of mice conditioned to either cocaine or social interaction place preference. Cocaine conditioning increased the spike frequency of neurons in the septal nuclei, whereas social interaction conditioning increased the spike frequency in the nucleus accumbens compared to saline control animals. In addition, social interaction conditioning decreased the amount of active neuron clusters in the nucleus accumbens. Our findings suggest that place preference conditioning for both drug and natural rewards may induce persistent changes in neuronal network activity in the nucleus accumbens and the septum that are still preserved in acute slice preparations. © 2015 S. Karger AG, Basel.

  10. Primordial nuclei

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The recent detection of intergalactic helium by NASA's Astro-2 mission backs up two earlier measurements by ESA and the University of California, San Diego, using instruments aboard the Hubble Space Telescope. Taken together, these results give strong evidence that this helium is primordial, confirming a key prediction of the Big Bang theory. The amount of helium the results imply could also account for some of the Universe's invisible dark matter - material which affects galactic motion but is otherwise undetectable. According to theory, helium nuclei formed at around 100 seconds after the Big Bang, but the amount of helium depended on even earlier events. Initially, protons turned into neutrons with the same probability that neutrons turned into protons. But after about one second, the Universe had cooled down enough for the weak interaction to freeze out. Neutrons continued to decay into the slightly lighter protons, whilst the opposite reaction became much more scarce. At around 100 seconds, thermonuclear fusion reactions could begin, and all the neutrons that were left became absorbed into helium nuclei, leaving the remaining protons locked up in hydrogen. The ratio of helium to hydrogen was therefore determined by events occurring when the Universe was just one second old. Standard models of primordial nucleosynthesis fix this ratio at slightly less than 2 5% by mass. All heavier elements were cooked up much later in the stars, and amount to less than 1 % of the Universe's mass. These predictions have been borne out remarkably well by observation, although proof of the primordial origins of hydrogen and helium has remained elusive until now. Big Bang nucleosynthesis goes on to estimate that primordial baryonic matter in the form of light nuclei could account for around 10% of the Universe's dark matter. All three recent measurements used the same technique of looking at distant quasars, some of the most luminous objects in the Universe, to

  11. Potential risk of weed outbreak by increasing biochar's application rates in slow-growth legume, lentil (Lens culinaris Medik.).

    Science.gov (United States)

    Safaei Khorram, Mahdi; Fatemi, Akram; Khan, Md Asaduzzaman; Kiefer, Rudolf; Jafarnia, Sasan

    2018-04-01

    Biochar amendment is a promising tool to improve the soil quality and, consequently, higher crop yield has received more attention during last decades. The positive effects of biochar have been attracting more attention especially in the areas with low precipitation rates, such as the Middle East, due to low soil organic carbon content, higher drought intensity, and increasing demands for food production. However, biochar can lead to lower herbicide efficacy, resulting in higher consumption of herbicides. In this study, the impact of two biochars on soil properties, plant growth, and fomesafen efficacy under rain-fed condition was investigated. Biochar amendment at the rate of 5 t ha -1 improved soil quality and plant growth by 40-200% and 46-57%, respectively, compared to the control. The increase of biochar application rate from 5 t ha -1 to 15 t ha -1 showed small additional positive effects on soil and lentil as the tested crop plant, whereas the growth of weeds elevated by 200% in this case. Albeit biochar application could be an effective way to improve the soil fertility, the potential risk of weed outbreak in the long term should be evaluated carefully before the use of biochar amendment at field scale. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  12. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Shin, Jung Hyuck; Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin

    2011-01-01

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

  13. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; Agarwal, P

    2010-01-01

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

  14. Converging or Diverging Lens?

    Science.gov (United States)

    Branca, Mario

    2013-01-01

    Why does a lens magnify? Why does it shrink objects? Why does this happen? The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A converging lens can also act as a diverging lens. (Contains 4 figures.)

  15. An electrophoretic study of the soluble lens proteins from the Indian mackerel, Rastrelliger kanagurta (Cuv)

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    Soluble eye lens nuclei proteins of the Indian mackerel Rastrelliger kanagurta were studied by cellogel electrophoresis, to see whether there are any intra species variations. A distinct pattern characterised by the number of bands, mobility...

  16. Soluble lens protein polymorphism in flying fishes from the central Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    Soluble eye lens nuclei proteins of flying-fishes were studied by cellogel electrophoresis. Three distinct patterns characterized by the number of bands, mobility and staining intensity were observed. Morphological studies of these fishes showed...

  17. Inter-specific and intraspecific eye lens protein differences in some sciaenid fishes from Goa coast

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    Soluble eye lens nuclei proteins of sciaenid fishes were studied by cellogel electrophoresis. Four distinct patterns characterized by the number of bands, mobility and staining intensity were observed. Morphological studies of these fishes showed...

  18. LENS spectroscopy of low energy solar neutrinos

    CERN Document Server

    Schönert, S

    2001-01-01

    The LENS experiments will measure energy resolved sub-MeV solar electron-neutrinos ( nu /sub e/) in real time via inverse beta - transition populating an isomeric state in the daughter nuclei. The subsequent de-excitation provides a delayed coincidence tag which discriminates against background. A liquid scintillation detector loaded with 20 t of Yb would yield an event rate of 190 pp- and 175 /sup 7/Be neutrinos per year. Essential information on neutrino mixing and masses can be derived.

  19. Single lens to lens duplication: The missing link

    OpenAIRE

    Bhatt, Rupal; Jethani, Jitendra; Saluja, Praveen; Bharti, Vinay

    2008-01-01

    Congenital anomalies of the lens include a wide range from lens coloboma to primary aphakia and doubling of lens. There have been few case reports of double lens; the etiology suggested is metaplastic changes in the surface ectoderm that leads to formation of two lens vesicles and hence resulting in double lens. We report a case with bilobed lens, which raises the possibility of explaining the etiology of double lens.

  20. Contact Lens Care

    Science.gov (United States)

    ... Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More sharing ... www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative Contact ...

  1. The tumor suppressor gene Trp53 protects the mouse lens against posterior subcapsular cataracts and the BMP receptor Acvr1 acts as a tumor suppressor in the lens

    Directory of Open Access Journals (Sweden)

    Luke A. Wiley

    2011-07-01

    We previously found that lenses lacking the Acvr1 gene, which encodes a bone morphogenetic protein (BMP receptor, had abnormal proliferation and cell death in epithelial and cortical fiber cells. We tested whether the tumor suppressor protein p53 (encoded by Trp53 affected this phenotype. Acvr1 conditional knockout (Acvr1CKO mouse fiber cells had increased numbers of nuclei that stained for p53 phosphorylated on serine 15, an indicator of p53 stabilization and activation. Deletion of Trp53 rescued the Acvr1CKO cell death phenotype in embryos and reduced Acvr1-dependent apoptosis in postnatal lenses. However, deletion of Trp53 alone increased the number of fiber cells that failed to withdraw from the cell cycle. Trp53CKO and Acvr1;Trp53DCKO (double conditional knockout, but not Acvr1CKO, lenses developed abnormal collections of cells at the posterior of the lens that resembled posterior subcapsular cataracts. Cells from human posterior subcapsular cataracts had morphological and molecular characteristics similar to the cells at the posterior of mouse lenses lacking Trp53. In Trp53CKO lenses, cells in the posterior plaques did not proliferate but, in Acvr1;Trp53DCKO lenses, many cells in the posterior plaques continued to proliferate, eventually forming vascularized tumor-like masses at the posterior of the lens. We conclude that p53 protects the lens against posterior subcapsular cataract formation by suppressing the proliferation of fiber cells and promoting the death of any fiber cells that enter the cell cycle. Acvr1 acts as a tumor suppressor in the lens. Enhancing p53 function in the lens could contribute to the prevention of steroid- and radiation-induced posterior subcapsular cataracts.

  2. Barriers in the energy of deformed nuclei

    Directory of Open Access Journals (Sweden)

    V. Yu. Denisov

    2014-06-01

    Full Text Available Interaction energy between two nuclei considering to their deformations is studied. Coulomb and nuclear in-teraction energies, as well as the deformation energies of both nuclei, are taken into account at evaluation of the interaction energy. It is shown that the barrier related to the interaction energy of two nuclei depends on the de-formations and the height of the minimal barrier is evaluated. It is obtained that the heavier nucleus-nucleus sys-tems have large deformation values at the lowest barrier. The difference between the barrier between spherical nuclei and the lowest barrier between deformed nuclei increases with the mass and the charge of the interacting nuclei.

  3. Role of Aquaporin 0 in lens biomechanics

    International Nuclear Information System (INIS)

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

    2015-01-01

    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

  4. Measurement of the absolute activity of alpha or beta emitters by measuring product nuclei (daughter) activity increase or by studing its radioactive decay

    International Nuclear Information System (INIS)

    Campos, L.C. de.

    1981-01-01

    A new method for determining absolute activity of alpha or beta emitters by measuring daughter product radioactive decay is presented. The separation method of UX from hexahydrated uranyl nitrate UO 2 (NO 3 ) 2 6H 2 O based on its dissolution in ethyl ether is described and the accuracy of this method is shown. The factors which accuate on total efficiency of a Geiger Mueller detector for beta particles are determined. The possibility to determine the mass of precursor element by daughter nuclei activity is shown. The results are compared with the one obtained by direct measurement of the mass (or number of atoms) of precursor radioactive substance and with theoretical values calculated for isotopes in secular equilibrium. (Author) [pt

  5. Aberration design of zoom lens systems using thick lens modules.

    Science.gov (United States)

    Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

    2014-12-20

    A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

  6. Theory of magic nuclei

    International Nuclear Information System (INIS)

    Nosov, V.G.; Kamchatnov, A.M.

    A consistent theory of the shell and magic oscillations of the masses of spherical nuclei is developed on the basis of the Fermi liquid concept of the energy spectrum of nuclear matter. A ''magic'' relationship between the system's dimensions and the limiting momentum of the quasi-particle distribution is derived; an integer number of the de Broglie half-waves falls on the nuclear diameter. An expression for the discontinuity in the nucleon binding energy in the vicinity of a magic nucleus is obtained. The role of the residual interaction is analyzed. It is shown that the width of the Fermi-surface diffuseness due to the residual interaction is proportional to the squared vector of the quasi-particle orbital angular momentum. The values of the corresponding proportionality factors (the coupling constant for quasi particles) are determined from the experimental data for 52 magic nuclei. The rapid drop of the residual interaction with increasing nuclear size is demonstrated. (7 figures, 3 tables) (U.S.)

  7. Studies of exotic nuclei

    International Nuclear Information System (INIS)

    Angelique, J.C.; Orr, N.A.

    1997-01-01

    The study of the nuclei far off stability valley is of much interest for testing the nuclear models established for the stable nuclei but also for astrophysics to understand the nucleosynthesis. Experiments aim to measure the mass and lifetime, to build the decay schemes and also to study the structure and the properties of these nuclei. The radioactive beam group focused its research on light neutron-rich nuclei having a halo neutron structure. Mass measurements in N ∼ Z nuclei namely in A ∼ 60-80 proton-rich nuclei, important for understanding the rp process, are mentioned, as well as in nuclei in the 100 Sn region. In the newly obtained 26 O and 28 O nuclei the lifetimes, the probabilities of emission of one for more neutrons were determined. The data analysis has permitted to determine also for the first time the lifetimes of 27,29 F and 30 Ne. Studies of nuclei in the 100 Sn region, near the proton drip line in the ground and isomeric states are now under way. The spectroscopy (energy levels, gamma emissions, etc.) of the neutron-rich nuclei produced by the 36 S fragmentation has been carried out in 31 Ne, 17 B and 29 F. Studies by Coulomb excitation of the 2 + excited states and associated probability B (E2) in O, Ne, Ni and Zn are now analysed

  8. Nuclei and quantum worlds

    International Nuclear Information System (INIS)

    Chomaz, Ph.

    2000-01-01

    This document gathers the slides and their commentaries that have been presented at the conference 'physics and fundamental questions' by P. Chomaz. The author reviews the different quantum aspects of nuclei: tunnel effect, symmetries, magic numbers, wave functions, size, shapes and deformations. The author shows that nuclei are quantum objects of great complexity, their structures are not yet well understood and the study of exotic nuclei will continue bringing valuable information

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

  10. Pairing correlations in nuclei

    International Nuclear Information System (INIS)

    Baba, C.V.K.

    1988-01-01

    There are many similarities between the properties of nucleons in nuclei and electrons in metals. In addition to the properties explainable in terms of independent particle motion, there are many important co-operative effects suggesting correlated motion. Pairing correlation which leads to superconductivity in metals and several important properties in nuclei , is an exmple of such correlations. An attempt has been made to review the effects of pairing correlations in nuclei. Recent indications of reduction in pairing correlations at high angular momenta is discussed. A comparision between pairing correlations in the cases of nuclei and electrons in metals is attempted. (author). 20 refs., 10 figs

  11. High-spin excitations of atomic nuclei

    International Nuclear Information System (INIS)

    Xu Furong; National Laboratory of Heavy Ion Physics, Lanzhou; Chinese Academy of Sciences, Beijing

    2004-01-01

    The authors used the cranking shell model to investigate the high-spin motions and structures of atomic nuclei. The authors focus the collective rotations of the A∼50, 80 and 110 nuclei. The A∼50 calculations show complicated g spectroscopy, which can have significant vibration effects. The A≅80 N≅Z nuclei show rich shape coexistence with prolate and oblate rotational bands. The A≅110 nuclei near the r-process path can have well-deformed oblate shapes that become yrast and more stable with increasing rotational frequency. As another important investigation, the authors used the configuration-constrained adiabatic method to calculate the multi-quasiparticle high-K states in the A∼130, 180 and superheavy regions. The calculations show significant shape polarizations due to quasi-particle excitations for soft nuclei, which should be considered in the investigations of high-K states. The authors predicted some important high-K isomers, e.g., the 8 - isomers in the unstable nuclei of 140 Dy and 188 Pb, which have been confirmed in experiments. In superheavy nuclei, our calculations show systematic existence of high-K states. The high-K excitations can increase the productions of synthesis and the survival probabilities of superheavy nuclei. (authors)

  12. Refractive neutron lens

    International Nuclear Information System (INIS)

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

    2013-01-01

    Model of the refractive neutron lens is proposed. System of N lenses acts as one thin lens with a complex refraction index n*. The maximum number N max of individual lenses for 'thick' neutron lens is calculated. Refractive neutron lens properties (resolution, focal depth) as function of resolution factor F 0 =ρbc/μ and depth of field factor dF 0 =λF 0 =λρbc/μ are calculated. It is shown that micro resolution of the refractive neutron optics is far from the wavelength in size and its open possibilities for progress in refractive neutron optics. (authors)

  13. 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

    2015-07-01

    To determine if the lens volume changes during accommodation. 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. 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. 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.

  14. Nuclei with exotic constituents

    International Nuclear Information System (INIS)

    Yamazaki, Toshimitsu.

    1990-08-01

    We discuss various interesting features in the behavior of exotic constituents of nuclei such as hyperons and mesons, in particular, with emphases on the aspect of exotic halos which are formed in general by short-range repulsion and long-range attraction. Specifically, Λ and Σ hypernuclei and pionic nuclei are discussed. (author)

  15. Neutron rich nuclei

    International Nuclear Information System (INIS)

    Foucher, R.

    1979-01-01

    If some β - emitters are particularly interesting to study in light, medium, and heavy nuclei, another (and also) difficult problem is to know systematically the properties of these neutron rich nuclei far from the stability line. A review of some of their characteristics is presented. How far is it possible to be objective in the interpretation of data is questioned and implications are discussed

  16. Baryon resonances in nuclei

    International Nuclear Information System (INIS)

    Arenhoevel, H.

    1977-01-01

    The field of baryon resonances in nuclei is reviewed. Theoretical developments and experimental evidence as well are discussed. Special emphasis is laid on electromagnetic processes for the two nucleon system. Some aspects of real isobars in nuclei are touched upon. (orig.) [de

  17. Nuclei in high forms

    International Nuclear Information System (INIS)

    Szymanski, Z.; Berger, J.F.; Heenen, P.H.; Heyde, K.; Haas, B.; Janssens, R.; Paya, D.; Gogny, D.; Huber, G.; Bjoernholm, S.; Brack, M.

    1991-01-01

    The purpose of 1991 Joliot-Curie Summer School is to review the most advances in the understanding of the nuclei physics after the considerable progress in gamma spectroscopy. It covers the following topics: Highly and super-deformed nuclei, nuclear structures, mean-field approach and beyond, fission isomers, nuclear excitations with long lifetime and metal clusters

  18. Pair correlations in nuclei

    International Nuclear Information System (INIS)

    Shimizu, Yoshifumi

    2009-01-01

    Except for the closed shell nuclei, almost all nuclei are in the superconducting state at their ground states. This well-known pair correlation in nuclei causes various interesting phenomena. It is especially to be noted that the pair correlation becomes weak in the excited states of nuclei with high angular momentum, which leads to the pair phase transition to the normal state in the high spin limit. On the other hand, the pair correlation becomes stronger in the nuclei with lower nucleon density than in those with normal density. In the region of neutron halo or skin state of unstable nuclei, this phenomenon is expected to be further enhanced to be observed compared to the ground state of stable nuclei. An overview of those interesting aspects caused via the pair correlation is presented here in the sections titled 'pair correlations in ground states', pair correlations in high spin states' and 'pair correlations in unstable nuclei' focusing on the high spin state. (S. Funahashi)

  19. Eta mesons in nuclei

    International Nuclear Information System (INIS)

    Liu, L.C.

    1987-01-01

    The possibility of producing eta-mesic nuclei by the use of pions is discussed. If these nuclei are observed experimentally, then the binding energies of the eta in this new nuclear matter can be used to extract accurately the eta-N-N* coupling constant in a nucleus. The framework for these calculations is the coupled channel isobar model

  20. Peripheral Defocus of the Monkey Crystalline Lens With Accommodation in a Lens Stretcher

    Science.gov (United States)

    Maceo Heilman, Bianca; Manns, Fabrice; Ruggeri, Marco; Ho, Arthur; Gonzalez, Alex; Rowaan, Cor; Bernal, Andres; Arrieta, Esdras; Parel, Jean-Marie

    2018-01-01

    Purpose To characterize the peripheral defocus of the monkey crystalline lens and its changes with accommodation. Methods Experiments were performed on 15 lenses from 11 cynomolgus monkey eyes (age: 3.8–12.4 years, postmortem time: 33.5 ± 15.3 hours). The tissue was mounted in a motorized lens stretcher to allow for measurements of the lens in the accommodated (unstretched) and unaccommodated (stretched) states. A custom-built combined laser ray tracing and optical coherence tomography system was used to measure the paraxial on-axis and off-axis lens power for delivery angles ranging from −20° to +20° (in air). For each delivery angle, peripheral defocus was quantified as the difference between paraxial off-axis and on-axis power. The peripheral defocus of the lens was compared in the unstretched and stretched states. Results On average, the paraxial on-axis lens power was 52.0 ± 3.4 D in the unstretched state and 32.5 ± 5.1 D in the stretched state. In both states, the lens power increased with increasing delivery angle. From 0° to +20°, the relative peripheral lens power increased by 10.7 ± 1.4 D in the unstretched state and 7.5 ± 1.6 D in the stretched state. The change in field curvature with accommodation was statistically significant (P lens has greater curvature or relative peripheral power. Conclusions The cynomolgus monkey lens has significant accommodation-dependent curvature of field, which suggests that the lens asserts a significant contribution to the peripheral optical performance of the eye that also varies with the state of accommodation.

  1. Crystalline lens radioprotectors

    International Nuclear Information System (INIS)

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

    2003-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

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

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

    Science.gov (United States)

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

    2018-03-01

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

  4. Glycation precedes lens crystallin aggregation

    International Nuclear Information System (INIS)

    Swamy, M.S.; Perry, R.E.; Abraham, E.C.

    1987-01-01

    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 [ 3 H]NaBH 4 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

  5. Nucleons in nuclei, however

    International Nuclear Information System (INIS)

    Grange, P.; Mathiot, J.F.; Roy-Stephan, M.; Frascaria, R.; Gales, S.

    1990-01-01

    The topics presented at the 1989 Joliot-Curie Lectures are reported. Two main subjects were retained: a simplified description of the N-body motion of particles in the quasi-particle configuration; study of the dynamics of nuclear components which are not described by nucleons in their ground state. The following themes were presented: quasiparticles and the Green functions, relativistic aspects of the quasiparticle concept, the dimensions of nucleons in the nuclei and the EMC effect, quarks and gluons in the nuclei, the delta in the nuclei, the strangeness, quasiparticles far from the Fermi sea, diffusion of electrons, stellar evolution and nucleosynthesis [fr

  6. Dynamic polarisation of nuclei

    International Nuclear Information System (INIS)

    Borghini, M.; Abragam, A.

    1961-01-01

    In magnetic fields of about 13000 gauss, at a temperature of 1.5 deg. K, in samples of about 2 mm 3 , we have obtained by the 'solid effect' (application of a magnetic field at an appropriate frequency around 35000 MHz), nuclear polarizations /I of a few percent: 19 per cent for hydrogen nuclei in single crystals of La 2 Mg 3 (NO 3 ) 12 , 24H 2 O; 5 per cent for hydrogen nuclei in polystyrene; 6 per cent for fluorine nuclei in single crystals of LiF. (author) [fr

  7. Capsular 'pits' in the human lens.

    OpenAIRE

    Harris, M. L.; Brown, N. A.; Shun-Shin, G. A.; Smith, G. T.

    1992-01-01

    The lens capsule is an atypical basement membrane surrounding the lens epithelial cells and lens fibres which make up the remainder of the human lens. A seemingly unreported morphological change visible in the lens capsule with the biomicroscope is described.

  8. The influence of end of day silicone hydrogel daily disposable contact lens fit on ocular comfort, physiology and lens wettability.

    Science.gov (United States)

    Wolffsohn, James; Hall, Lee; Mroczkowska, Stephanie; Hunt, Olivia A; Bilkhu, Paramdeep; Drew, Tom; Sheppard, Amy

    2015-10-01

    To quantify the end-of-day silicone-hydrogel daily disposable contact lens fit and its influence of on ocular comfort, physiology and lens wettability. Thirty-nine subjects (22.1±3.5 years) were randomised to wear each of 3 silicone-hydrogel daily-disposable contact lenses (narafilcon A, delefilcon A and filcon II 3), bilaterally, for one week. Lens fit was assessed objectively using a digital video slit-lamp at 8, 12 and 16h after lens insertion. Hyperaemia, non-invasive tear break-up time, tear meniscus height and comfort were also evaluated at these timepoints, while corneal and conjunctival staining were assessed on lens removal. Lens fit assessments were not different between brands (P>0.05), with the exception of the movement at blink where narafilcon A was more mobile. Overall, lag reduced but push-up speed increased from 8 to 12h (P0.05). Movement-on-blink was unaffected by wear-time (F=0.403, P=0.670). A more mobile lens fit with one brand did not indicate that person would have a more mobile fit with another brand (r=-0.06 to 0.63). Lens fit was not correlated with comfort, ocular physiology or lens wettability (P>0.01). Among the lenses tested, objective lens fit changed between 8h and 12h of lens wear. The weak correlation in individual lens fit between brands indicates that fit is dependent on more than ocular shape. Consequently, substitution of a different lens brand with similar parameters will not necessarily provide comparable lens fit. Copyright © 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  9. Quarks in nuclei

    International Nuclear Information System (INIS)

    Roberts, R.G.

    1984-11-01

    The paper concerns the behaviour of quarks in nuclei. Confinement size changes and dynamical rescaling; A dependence; low-x region; gluons and confinement size; and nucleons in a nucleus; are all discussed. (U.K.)

  10. The shape of nuclei

    International Nuclear Information System (INIS)

    Mackintosh, R.S.

    1977-01-01

    For the class of nuclei which are 'strongly deformed' it is possible to introduce the idea of an empirically measurable static nuclear shape. The limitations of this concept as applied to nuclei (fundamentally quantum-mechanical objects) are discussed. These are basically the limitations of the rotational model which must be introduced in order to define and measure nuclear shape. A unified discussion of the ways in which the shape has been parametrized is given with emphasis on the fact that different parametrizations correspond to different nuclear structures. Accounts of the various theoretical procedures for calculating nuclear shapes and of the interaction between nuclear shapes and nuclear spectroscopy are given. A coherent account of a large subset of nuclei (strongly deformed nuclei) can be given by means of a model in which the concept of nuclear shape plays a central role. (author)

  11. Photosensitized oxidation in the ocular lens: evidence for photosensitizers endogenous to the human lens

    International Nuclear Information System (INIS)

    Zigler, J.S. Jr.; Goosey, J.D.

    1981-01-01

    Numerous investigators have attempted to associate near UV light exposure with various changes which occur to lens crystallins during aging and cataractogenesis. Recently it was shown that in vitro singlet oxygen mediated oxidation of lens crystallins produces effects very similar to those documented for crystallins from old or cataractous lenses and it was suggested that near UV photodynamic effects may play a major role in vivo in aging in the human lens. It has now been shown that certain oxidation products of tryptophan which have been identified in human lens can act as near UV photosensitizers, producing singlet oxygen. The insoluble protein fraction from human cataracts was shown to have the capacity to act as a photosensitizer. An age-related increase in photosensitizing capacity was also demonstrated in the soluble crystallins from human lens. These findings are discussed with respect to development of pigmented nuclear cataracts. (author)

  12. Post-lens tear turbidity and visual quality after scleral lens wear.

    Science.gov (United States)

    Carracedo, Gonzalo; Serramito-Blanco, Maria; Martin-Gil, Alba; Wang, Zicheng; Rodriguez-Pomar, Candela; Pintor, Jesús

    2017-11-01

    The aim was to evaluate the turbidity and thickness of the post-lens tear layer and its effect on visual quality in patients with keratoconus after the beginning of lens wear and before lens removal at the end of eight hours. Twenty-six patients with keratoconus (aged 36.95 ± 8.95 years) participated voluntarily in the study. The sample was divided into two groups: patients with intrastromal corneal ring (ICRS group) and patients without ICRS (KC group). Distance visual acuity (VA), contrast sensitivity, pachymetry, post-lens tear layer height and post-lens tear layer turbidity (percentage area occupied and number of particles per mm 2 ) were evaluated with optical coherence tomography before and after wearing a scleral lens. A significant increase of turbidity was found in all groups assessed (p turbidity parameters with distance VA but no correlation between turbidity and post-lens tear layer thickness at the beginning was found (p > 0.05). A strong correlation in all groups between the post-lens tear layer at the beginning and differences of tear layer thickness between two measures was also found (p turbidity. © 2017 Optometry Australia.

  13. Hot nuclei and fragmentation

    International Nuclear Information System (INIS)

    Guerreau, D.

    1993-01-01

    A review is made of the present status concerning the production of nuclei above 5 MeV temperature. Considerable progress has been made recently on the understanding of the formation and the fate of such hot nuclei. It appears that the nucleus seems more stable against temperature than predicted by static calculations. However, the occurrence of multifragment production at high excitation energies is now well established. The various experimental features of the fragmentation process are discussed. (author) 59 refs., 12 figs

  14. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Mike A. (Albuquerque, NM); Foreman, Larry R. (Los Alamos, NM)

    1997-01-01

    This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

  15. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, M.A.; Foreman, L.R.

    1997-07-08

    This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

  16. Gravitational lens effect and pregalactic halo objects

    International Nuclear Information System (INIS)

    Bontz, R.J.

    1979-01-01

    The changes in flux, position, and size of a distant extended (galaxy, etc.) source that result from the gravitational lens action of a massive opaque object are discussed. The flux increase is described by a single function of two parameters. One of these parameters characterizes the strength of the gravitational lens, the other describes the alignment of source and lens object. This function also describes the relative intensity of the images formed by lens. ( A similar formalism is discussed by Bourassa et al. for a point source). The formalism is applied to the problem of the galactic halo. It appears that a massive (10 1 2 M/sub sun/) spherical halo surrounding the visible part of the galaxy is consistent with the observable properties of extragalactic sources

  17. The total length of myocytes and capillaries, and total number of myocyte nuclei in the rat heart are time-dependently increased by growth hormone

    DEFF Research Database (Denmark)

    Brüel, Annemarie; Oxlund, Hans; Nyengaard, Jens Randel

    2005-01-01

    /kg/day) or vehicle for 5, 10, 20, 40, or 80 days. From the left ventricle (LV) histological sections were made and stereological methods applied. Linear regression showed that GH time-dependently increased: LV volume (r=0.96, P

  18. Electro-magnetic properties of heavy nuclei

    International Nuclear Information System (INIS)

    Otsuka, Takaharu

    1989-01-01

    Two topics of electro-magnetic properties of heavy nuclei are discussed. The first topic is the M1 excitation from well-deformed heavy nuclei, and the other is the sudden increase of the isotope shift as a function of N in going away from the closed shell. These problems are considered in terms of the particle-number projected (Nilsson-) BCS calculation. (author)

  19. Members of the bcl-2 and caspase families regulate nuclear degeneration during chick lens fibre differentiation.

    Science.gov (United States)

    Wride, M A; Parker, E; Sanders, E J

    1999-09-01

    The optical clarity of the lens is ensured by the programmed removal of nuclei and other organelles from the lens fibre cells during development. The morphology of the degenerating nuclei is similar to that observed during apoptosis and is accompanied by DNA fragmentation. Proteins encoded by the bcl-2 proto-oncogene family are important in either promoting or inhibiting apoptosis, and caspases are involved in downstream proteolytic events. Here, the expression of bcl-2 family members (bcl-2, bax, bad, and bcl-x(s/l)) and caspases-1, -2, -3, -4, and -6 was investigated through a range of stages of chick lens development using immunocytochemistry, Western blotting, and affinity labelling for caspases using biotinylated caspase inhibitors. Using differentiating lens epithelial cell cultures, it was demonstrated that the addition to cultures of synthetic peptide inhibitors of caspases -1, -2, -4, -6, and -9 brought about a 50-70% reduction in the number of degenerating nuclei per unit area of culture, as assessed by image analysis. These effects were comparable to those seen when general inhibitors of caspases were added to cultures. On the other hand, inhibitors of caspases-3 and -8 were not effective in significantly reducing the number of TUNEL-labelled nuclei. Expression of the caspase substrates poly(ADP-ribose) polymerase (PARP) and the 45-kDa subunit of DNA fragmentation factor (DFF 45) was also observed in the developing lens. Western blots of cultures to which caspase inhibitors were added revealed alterations in the PARP cleavage pattern, but not in that of DFF. These results demonstrate a role for members of the bcl-2 family and caspases in the degeneration of lens fibre cell nuclei during chick secondary lens fibre development and support the proposal that this process has many characteristics in common with apoptosis. Copyright 1999 Academic Press.

  20. Colored Contact Lens Dangers

    Medline Plus

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

  1. Colored Contact Lens Dangers

    Medline Plus

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

  2. The lens and cataracts.

    Science.gov (United States)

    Matthews, Andrew G

    2004-08-01

    It is conservatively estimated that some form of lens opacity is present in 5% to 7% of horses with otherwise clinically normal eyes.These opacities can range from small epicapsular remnants of the fetal vasculature to dense and extensive cataract. A cataract is defined technically as any opacity or alteration in the optical homogeneity of the lens involving one or more of the following: anterior epithelium, capsule, cortex, or nucleus. In the horse, cataracts rarely involve the entire lens structure (ie, complete cataracts) and are more usually localized to one anatomic landmark or sector of the lens. Complete cataracts are invariably associated with overt and significant visual disability. Focal or incomplete cataracts alone seldom cause any apparent visual dysfunction in affected horses,however.

  3. Colored Contact Lens Dangers

    Medline Plus

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

  4. Colored Contact Lens Dangers

    Medline Plus

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

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... contacto de color Sep. 26, 2013 It started as an impulsive buy from a souvenir shop, but ... require the same level of care or consideration as a standard contact lens because they can be ...

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... With Proper Contact Lens Care Apr 23, 2018 Solar Eclipse Inflicts Damage in the Shape of the ... edging closer, thanks to a wave of new technologies aiming to fix failing eye parts with human- ...

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... glow-in-the-dark lizard lenses, costume contacts can certainly add a spooky, eye-popping touch. But ... consideration as a standard contact lens because they can be purchased over-the-counter or on the ...

  8. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... valid prescription that includes the brand name, lens measurements, and expiration date. Purchase the colored contact lenses ... with human-made versions. U.S. News Highlights the Value of Ophthalmologists APR 20, 2018 By Dan T. ...

  9. Vortex gas lens

    Science.gov (United States)

    Bogdanoff, David W.; Berschauer, Andrew; Parker, Timothy W.; Vickers, Jesse E.

    1989-01-01

    A vortex gas lens concept is presented. Such a lens has a potential power density capability of 10 to the 9th - 10 to the 10th w/sq cm. An experimental prototype was constructed, and the divergence half angle of the exiting beam was measured as a function of the lens operating parameters. Reasonably good agreement is found between the experimental results and theoretical calculations. The expanded beam was observed to be steady, and no strong, potentially beam-degrading jets were found to issue from the ends of the lens. Estimates of random beam deflection angles to be expected due to boundary layer noise are presented; these angles are very small.

  10. 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 ...

  11. Colored Contact Lens Dangers

    Medline Plus

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

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms ...

  13. 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. ...

  14. Colored Contact Lens Dangers

    Medline Plus

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

  15. CONTACT LENS RELATED CORNEAL ULCER

    Directory of Open Access Journals (Sweden)

    AGARWAL P

    2010-01-01

    Full Text Available A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are:overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. The presenting symptoms of contact lens related corneal ulcers include eye discomfort, foreign body sensation and lacrimation. More serious symptoms are redness (especially circum-corneal injection, severe pain, photophobia, eye discharge and blurring of vision. The diagnosis is established by a thorough slit lamp microscopic examination with fluorescein staining and corneal scraping for Gram stain and culture of the infective organism. Delay in diagnosing and treatment can cause permanent blindness, therefore an early referral to ophthalmologist and commencing of antimicrobial therapy can prevent visual loss.

  16. Cosmology and unstable nuclei

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1995-01-01

    Primordial nucleosynthesis has established itself as one of the three pillars of Big Bang cosmology. Many of the Big Bang Nucleosynthesis reactions involve unstable nuclei. Hence there is a tight relationship hetween the subject of this conference and cosmology. The prime role of unstable nuclei in cosmology is related to lithium synthesis and the lack of cosmological synthesis of Be and B. These nuclei will thus be focused upon. Nucleosynthesis involves comparing calculated abundances with observed abundances. In general, abundance determinations are dominated by systematic rather than statistical errors, and work on bounding systematics is crucial. The quark-hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in Ω b are possible vis-a-vis the homogeneous model; hence the robustness of Ω b ∼0.05 is now apparent. (These calculations depend critically on unstable nuclei.) The above argues that the bulk of the baryons in the universe are not producing visible light. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. Ω b ∼1 seems to be definitely excluded, so if Ω TOTAL =1, as some recent observations may hint, then non-baryonic dark matter is required. The implications of the recently reported halo microlensing events are discussed. In summary, it is argued that the physics of unstable nuclei affects the fundamental dark matter argument. ((orig.))

  17. The creation of new nuclei

    International Nuclear Information System (INIS)

    Armbruster, P.; Hessberger, F.P.

    1998-01-01

    In the last 60 years physicists have created 20 artificial elements beyond uranium. In 1934 Enrico Fermi predicted the creation of new elements by bombarding atoms with neutrons. This method led to the discovery of neptunium (Z=93), plutonium, americium, curium, berkelium, californium, einsteinium and fermium (Z=100). In fact the capture of a neutron is followed by a beta-decay which increases the atomic number (Z) by one unit. Beyond Z=100 beta-decay no more occurs so a new approach was necessary. Between the American Lawrence Berkeley Laboratory and the Russian Dubna Institute a fierce competition broke out to produce new elements by bombarding transuranium nuclei with light elements such as helium, carbon, nitrogen. This new method required heavy equipment: ion accelerator and detectors but led to the creation of all the elements from Z=101 to Z=106. A new idea was to provoke the fusion of heavy nuclei such as lead and bismuth with colliding argon, nickel or zinc ion beams. This method called 'cold fusion' opened the way to reach the nuclei beyond Z=107. In 1996 the element Z=112 was the last discovered. The next step could be the element Z=114 for which a particular stability is expected. (A.C.)

  18. 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

  19. 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

  20. Critical-point nuclei

    International Nuclear Information System (INIS)

    Clark, R.M.

    2004-01-01

    It has been suggested that a change of nuclear shape may be described in terms of a phase transition and that specific nuclei may lie close to the critical point of the transition. Analytical descriptions of such critical-point nuclei have been introduced recently and they are described briefly. The results of extensive searches for possible examples of critical-point behavior are presented. Alternative pictures, such as describing bands in the candidate nuclei using simple ΔK = 0 and ΔK = 2 rotational-coupling models, are discussed, and the limitations of the different approaches highlighted. A possible critical-point description of the transition from a vibrational to rotational pairing phase is suggested

  1. Weak interactions with nuclei

    International Nuclear Information System (INIS)

    Walecka, J.D.

    1983-01-01

    Nuclei provide systems where the strong, electomagnetic, and weak interactions are all present. The current picture of the strong interactions is based on quarks and quantum chromodynamics (QCD). The symmetry structure of this theory is SU(3)/sub C/ x SU(2)/sub W/ x U(1)/sub W/. The electroweak interactions in nuclei can be used to probe this structure. Semileptonic weak interactions are considered. The processes under consideration include beta decay, neutrino scattering and weak neutral-current interactions. The starting point in the analysis is the effective Lagrangian of the Standard Model

  2. Quarks in nuclei

    International Nuclear Information System (INIS)

    Rho, M.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette

    1983-01-01

    Some features of quark degrees of freedom in nuclei are discussed in the light of recent developments in QCD. The principal aim of this talk is to propose, and give a tentative support to, the motion that one can study through nuclear matter different facets of the vacuum structure implied by quantum chromodynamics (QCD). This will be done using the recent (exciting) results obtained in particle physics, in particular lattice gauge calculations. Relevance of this aspect of problem to quark degrees of freedom as well as meson degrees of freedom in nuclei will be discussed. (orig.)

  3. Disintegration of comet nuclei

    Science.gov (United States)

    Ksanfomality, Leonid V.

    2012-02-01

    The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is only now that we have efficient enough space exploration tools to see comet nuclei and even - in the particular case of small comet Hartley-2 in 2010 - to watch their disintegration stage. There are also other suspected candidates for disintegration in the vast family of comet nuclei and other Solar System bodies.

  4. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2002-01-01

    The present collection of letters from JINR, Dubna, contains seven separate records on kinematic separation and mass analysis of heavy recoiling nuclei, dynamical effects prior to heavy ion fusion, VACTIV-DELPHI graphical dialog based program for the analysis of gamma-ray spectra, irradiation of nuclear emulsions in relativistic beams of 6 He and 3 H nuclei, optical and structural investigations of PLZT x/65/35 (x = 4, 8 %) ferroelectric ceramics irradiated by a high-current pulsed electron beam, the oscillating charge and first evidence for neutrinoless double beta decay

  5. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2001-01-01

    The present collection of letters from JINR, Dubna, contains seven separate records on physics from extra dimensions, new physics in the new millennium with GENIUS: double beta decay, dark matter, solar neutrinos, the (μ - , e + ) conversion in nuclei mediated by light Majorana neutrinos, exotic muon-to-positron conversion in nuclei: partial transition sum evaluation by using shell model, solar neutrino problem accounting for self consistent magnetohydrodynamics solution for solar magnetic fields, first neutrino observations from the Sudbury neutrino observatory and status report on BOREXINO and results of the muon-background measurements at CERN

  6. Rotational motion in nuclei

    International Nuclear Information System (INIS)

    Bohr, A.

    1976-01-01

    Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

  7. Symmetries and nuclei

    International Nuclear Information System (INIS)

    Henley, E.M.

    1987-01-01

    Nuclei are very useful for testing symmetries, and for studies of symmetry breaking. This thesis is illustrated for two improper space-time transformations, parity and time-reversal and for one internal symmetry: charge symmetry and independence. Recent progress and present interest is reviewed. 23 refs., 8 figs., 2 tabs

  8. Electroweak interactions in nuclei

    International Nuclear Information System (INIS)

    Henley, E.M.

    1984-06-01

    Topics include: introduction to electroweak theory; the Weinberg-Salam theory for leptons; the Weinberg-Salam theory for hadrons-the GIM mechanism; electron scattering as a probe of the electroweak interaction (observation of PV, the weak interaction for nucleons, and parity violation in atoms); and time reversed invariance and electric dipole moments of nucleons, nuclei, and atoms. 52 references

  9. Transfer involving deformed nuclei

    International Nuclear Information System (INIS)

    Rasmussen, J.O.; Guidry, M.W.; Canto, L.F.

    1985-03-01

    Results are reviewed of 1- and 2-neutron transfer reactions at near-barrier energies for deformed nuclei. Rotational angular momentum and excitation patterns are examined. A strong tendency to populating high spin states within a few MeV of the yrast line is noted, and it is interpreted as preferential transfer to rotation-aligned states. 16 refs., 12 figs

  10. Collisions with nuclei

    International Nuclear Information System (INIS)

    Gulamov, K.G.

    1987-01-01

    It is well known that interactions of high energy particles with nuclei, owing to possible intranuclear rescatterings, may provide information about the space-time behaviour of the production process. Therefore the main goals of these investigations are related with the attempts to study the space-time process of hadronization of coloured quarks and gluons produced at the initial stage of an interaction to white final state particles and to clarify the influence of composite quark-gluon structure of both the projectile and target on features of the production mechanisms. Since in both the initial and final states of these reactions the authors have strongly interacting multiparticle systems, it is of importance to study the collective properties of these systems. The questions to the point are: what is the degree of collectivization of particles newly produced in collisions with nuclei and what is the influence of the collective nature of a nucleus itself on the production mechanisms, in particular, what are the manifestations of possible multinucleon (multiquark) configurations in nuclei? It is obvious that the reductability of, say, hadron-nucleus (hA) interaction to hadron-nucleon (hN) collisions is directly related to the above problems. Due to time limitations the author discusses here only a few aspects of low p/sub t/ hA interactions which in his opinion are of importance for better understanding of general regularities of collisions with nuclei and for further investigations of the above problems

  11. Nucleons in nuclei (II)

    International Nuclear Information System (INIS)

    Laget, J.M.

    1988-01-01

    This summary is a review of our understanding of nuclei in terms of hadrons exchanging mesons. The open problems are: the determination of the high momentum components of nuclear systems, the role of the three-body forces and the nature of the short range correlations. The ways of studying these problems are discussed

  12. Electromagnetic structure of nuclei

    International Nuclear Information System (INIS)

    Arnold, R.G.

    1986-07-01

    A brief review is given of selected topics in the electromagnetic structure of nucleons and nuclei, including nucleon form factors from both quantum chromodynamics and electron scattering data, measurements of the deuteron and triton form factors, quasi-elastic scattering, and the EMC effect. 47 refs., 13 figs

  13. Rotational motion in nuclei

    International Nuclear Information System (INIS)

    Bohr, A.

    1977-01-01

    History is surveyed of the development of the theory of rotational states in nuclei. The situation in the 40's when ideas formed of the collective states of a nucleus is evoked. The general rotation theory and the relation between the single-particle and rotational motion are briefly discussed. Future prospects of the rotation theory development are indicated. (I.W.)

  14. Mesons and light nuclei

    International Nuclear Information System (INIS)

    Truhlik, E.; Mach, R.

    1992-01-01

    62 papers and one summary talk were presented at the conference, on subject matters in between nuclear physics (mainly light nuclei) and elementary particle physics, as indicated by the session headings (1) Electroweak nuclear interaction (2) Nuclear physics with pions and antiprotons (3) Nuclear physics with strange particles (4) Relativistic nuclear physics (5) Quark degrees of freedom. (Quittner)

  15. Radii of radioactive nuclei

    International Nuclear Information System (INIS)

    Mittig, W.; Plagnol, E.; Schutz, Y.

    1989-11-01

    A new simple direct method for the measurement of the total reaction cross section (σ R ) for several light radioactive nuclei (A≤40) is developed. From that, the reduced strong absorption radii (r o 2 ) are obtained. A comparison is made with data obtained by other techniques. A strong isospin dependence of the nuclear radii is observed. (L.C.) [pt

  16. Alpha clustering in nuclei

    International Nuclear Information System (INIS)

    Hodgson, P.E.

    1990-01-01

    The effects of nucleon clustering in nuclei are described, with reference to both nuclear structure and nuclear reactions, and the advantages of using the cluster formalism to describe a range of phenomena are discussed. It is shown that bound and scattering alpha-particle states can be described in a unified way using an energy-dependent alpha-nucleus potential. (author)

  17. Particles, imaging and nuclei

    International Nuclear Information System (INIS)

    Harris, J.

    1986-01-01

    The book on particles, imaging and nuclei is one of the Background Readers for the Revised Nuffield Advanced Physics course. The contents contain five educational articles, which extend concepts covered in the course and examine recent developments in physics. Four of the articles on:- particles and the forces of nature, radioisotopes, lasers probe the atomic nucleus, and nuclear history, are indexed separately. (UK)

  18. Comparison of clear lens extraction and collamer lens implantation in high myopia

    Directory of Open Access Journals (Sweden)

    Ahmed M Emarah

    2010-05-01

    Full Text Available Ahmed M Emarah, Mostafa A El-Helw, Hazem M YassinCairo University, Cairo, EgyptAim: To compare the outcomes of clear lens extraction and collamer lens implantation in high myopia.Patients and methods: Myopic patients younger than 40 years old with more than 12 diopters of myopia or who were not fit for laser-assisted in situ keratomileusis were included. Group 1 comprised patients undergoing clear lens extraction and Group 2 patients received the Visian implantable collamer lens. Outcome and complications were evaluated.Results: Postoperative best corrected visual acuity was -0.61 ± 0.18 in Group 1 and 0.79 ± 0.16 in Group 2. In Group 1, 71.4% achieved a postoperative uncorrected visual acuity better than the preoperative best corrected visual acuity, while only 51.8% patients achieved this in Group 2. Intraocular pressure decreased by 12.55% in Group 1, and increased by 15.11% in Group 2. Corneal endothelial cell density decreased by 4.47% in Group 1 and decreased by 5.67% in Group 2. Posterior capsule opacification occurred in Group 1. In Group 2, lens opacification occurred in 11.11%, significant pigment dispersion in 3.7%, and pupillary block glaucoma in 3.7%.Conclusion: Clear lens extraction presents less of a financial load up front, and less likelihood of the need for a secondary intervention in the future. Clear lens extraction is a more viable solution in developing countries with limited financial resources.Keywords: clear lens extraction, implantable collamer lens, myopia

  19. Symmetric lens with extended depth of focus

    OpenAIRE

    Cho, Sung Nae

    2008-01-01

    The lens surface profile is derived based on the instantaneous focal length versus the lens radius data. The lens design based on instantaneous focal length versus the lens radius data has many useful applications in software assisted image focusing technology.

  20. The decay of hot nuclei

    International Nuclear Information System (INIS)

    Moretto, L.G.; Wozniak, G.J.

    1988-11-01

    The formation of hot compound nuclei in intermediate-energy heavy ion reactions is discussed. The statistical decay of such compound nuclei is responsible for the abundant emission of complex fragments and high energy gamma rays. 43 refs., 23 figs

  1. Isotope shifts in unstable nuclei

    International Nuclear Information System (INIS)

    Rebel, H.

    1980-05-01

    Current experimental investigations of isotope shifts in atomic spectra of unstable nuclei and the resulting information about size and shape of nuclei far off stability are discussed with reference to some representative examples. (orig.)

  2. A catoptric lens

    International Nuclear Information System (INIS)

    Rambauske, W.R.

    1973-01-01

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

  3. Energetic Nuclei, Superdensity and Biomedicine

    Science.gov (United States)

    Baldin, A. M.

    1977-01-01

    High-energy, relativistic nuclei were first observed in cosmic rays. Studing these nuclei has provided an opportunity for analyzing the composition of cosmic rays and for experimentally verifying principles governing the behavior of nuclear matter at high and super-high temperatures. Medical research using accelerated nuclei is suggested.…

  4. Nuclear magnetic resonance studies of lens transparency

    International Nuclear Information System (INIS)

    Beaulieu, C.F.

    1989-01-01

    Transparency of normal lens cytoplasm and loss of transparency in cataract were studied by nuclear magnetic resonance (NMR) methods. Phosphorus ( 31 P) NMR spectroscopy was used to measure the 31 P constituents and pH of calf lens cortical and nuclear homogenates and intact lenses as a function of time after lens enucleation and in opacification produced by calcium. Transparency was measured with laser spectroscopy. Despite complete loss of adenosine triphosphate (ATP) within 18 hrs of enucleation, the homogenates and lenses remained 100% transparent. Additions of calcium to ATP-depleted cortical homogenates produced opacification as well as concentration-dependent changes in inorganic phosphate, sugar phosphates, glycerol phosphorylcholine and pH. 1 H relaxation measurements of lens water at 200 MHz proton Larmor frequency studied temperature-dependent phase separation of lens nuclear homogenates. Preliminary measurements of T 1 and T 2 with non-equilibrium temperature changes showed a change in the slope of the temperature dependence of T 1 and T 2 at the phase separation temperature. Subsequent studies with equilibrium temperature changes showed no effect of phase separation on T 1 or T 2 , consistent with the phase separation being a low-energy process. 1 H nuclear magnetic relaxation dispersion (NMRD) studies (measurements of the magnetic field dependence of the water proton 1/T 1 relaxation rates) were performed on (1) calf lens nuclear and cortical homogenates (2) chicken lens homogenates, (3) native and heat-denatured egg white and (4) pure proteins including bovine γ-II crystallin bovine serum albumin (BSA) and myoglobin. The NMRD profiles of all samples exhibited decreases in 1/T 1 with increasing magnetic field

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

    Directory of Open Access Journals (Sweden)

    Niamat Hussain

    2016-01-01

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

  6. A Tribute to Len Barton

    Science.gov (United States)

    Tomlinson, Sally

    2010-01-01

    This article constitutes a short personal tribute to Len Barton in honour of his work and our collegial relationship going back over 30 years. It covers how Len saw his intellectual project of providing critical sociological and political perspectives on special education, disability and inclusion, and his own radical political perspectives. Len's…

  7. Luneburg lens in silicon photonics.

    Science.gov (United States)

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

    2011-03-14

    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.

  8. Lubricant effects on low Dk and silicone hydrogel lens comfort.

    Science.gov (United States)

    Ozkan, Jerome; Papas, Eric

    2008-08-01

    To investigate the influence of three lubricants of varying viscosity, on postinsertion and 6 h comfort with contact lens wear. Comfort and associated symptoms of dryness were assessed in 15 experienced contact lens wearers. Subjects wore a low Dk lens in one eye and a silicone hydrogel in the other and participated in four separate trials involving no lubricant (baseline), saline, and two commercially available lubricants of differing viscosity. The in-eye lubricants were used immediately following lens insertion and every 2 h postinsertion for a 6 h wear period. Postlens insertion comfort was significantly better for both lens types when lubricants or saline were used compared with no lubricant use. After 6 h lens wear, comfort was influenced by lens type and not by in-eye lubricant or saline use. Also after 6 h lens wear, less dryness sensation was reported for silicone hydrogel lenses when using lubricants but not saline. Although lubricant use does help reduce dryness symptoms with silicone hydrogel lens wear, there appears to be minimal longer-term benefit to comfort. Furthermore, increased lubricant viscosity did not lead to improved longer-term comfort.

  9. Colored Contact Lens Dangers

    Medline Plus

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

  10. Contact Lens Risks

    Science.gov (United States)

    ... There is a risk of eye infection from bacteria in swimming pool water, hot tubs, lakes and the ocean Replace your contact lens storage case every 3 months or as directed by your eye care professional. Other Risks of Contact Lenses Other risks of contact lenses include pink eye ( ...

  11. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

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

  12. The Lens of Chemistry

    Science.gov (United States)

    Thalos, Mariam

    2013-01-01

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

  13. Colored Contact Lens Dangers

    Medline Plus

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

  14. Quadrupole magnetic lens

    International Nuclear Information System (INIS)

    Piskunov, V.A.

    1981-01-01

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

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... can 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. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into ...

  16. Stability and production of superheavy nuclei

    International Nuclear Information System (INIS)

    Moeller, P.; Los Alamos National Lab., NM; Nix, J.R.

    1997-01-01

    Beyond uranium heavy elements rapidly become increasingly unstable with respect to spontaneous fission as the proton number Z increases, because of the disruptive effect of the long-range Coulomb force. However, in the region just beyond Z = 100 magic proton and neutron numbers and the associated shell structure enhances nuclear stability sufficient to allow observation of additional nuclei. Some thirty years ago it was speculated that an island of spherical, relatively stable superheavy nuclei would exist near the next doubly magic proton-neutron combination beyond 208 Pb, that is, at proton number Z 114 and neutron number N = 184. Theory and experiment now show that there also exists a rock of stability in the vicinity of Z = 110 and N = 162 between the actinide region, which previously was the end of the peninsula of known elements, and the predicted island of spherical superheavy nuclei slightly southwest of the magic numbers Z = 114 and N = 184. The authors review here the stability properties of the heavy region of nuclei. Just as the decay properties of nuclei in the heavy region depend strongly on shell structure, this structure also dramatically affects the fusion entrance channel. The six most recently discovered new elements were all formed in cold-fusion reactions. They discuss here the effect of the doubly magic structure of the target in cold-fusion reactions on the fusion barrier and on dissipation

  17. Disintegration of comet nuclei

    International Nuclear Information System (INIS)

    Ksanfomality, Leonid V

    2012-01-01

    The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is only now that we have efficient enough space exploration tools to see comet nuclei and even - in the particular case of small comet Hartley-2 in 2010 - to watch their disintegration stage. There are also other suspected candidates for disintegration in the vast family of comet nuclei and other Solar System bodies. (physics of our days)

  18. Pions scatter by nuclei

    International Nuclear Information System (INIS)

    Huefner, J.

    1975-01-01

    Are pions a good tool to study nuclei. If the emphasis of this question rests on ''tool'', the answer must be ''not yet.'' The reason: one does not even understand how a pion interacts with a nucleus. This is part of the many-body problem for strongly interacting particles and its study is a basic problem in physics. One must investigate questions like: Can one understand pion-nucleus interactions from pion-nucleon physics. How does a Δ-resonance look in nuclei. Once one has solved those basic problems, there will be spinoffs in medical, technical and nuclear areas. Then pions can be used as a tool to study nuclear properties

  19. Chaos in collective nuclei

    International Nuclear Information System (INIS)

    Whelan, N.D.

    1993-01-01

    Random Matrix Theory successfully describes the statistics of the low-lying spectra of some nuclei but not of others. It is currently believed that this theory applies to systems in which the corresponding classical motion is chaotic. This conjecture is tested for collective nuclei by studying the Interacting Boson Model. Quantum and classical measures of chaos are proposed and found to be in agreement throughout the parameter space of the model. For some parameter values the measures indicate the presence of a previously unknown approximate symmetry. A phenomenon called partial dynamical symmetry is explored and shown to lead to a suppression of chaos. A time dependent function calculated from the quantum spectrum is discussed. This function is sensitive to the extent of chaos and provides a robust method of analyzing experimental spectra

  20. Chaotic behavior in nuclei

    International Nuclear Information System (INIS)

    Mitchel, G.; Shriner, J.

    2005-01-01

    Although the predictions of Random Matrix Theory (RMT) were available by the early 1960s, data of sufficiently high quality to adequately test the theory were only obtained a decade later by Rainwater. It was another decade later that Bohigas, Haq and Pandey combined the best available nuclear resonance data - the Columbia neutron resonances in heavy nuclei and the TUNL proton resonances in lighter nuclei - to form the Nuclear Data Ensemble. They obtained excellent agreement for the level statistics with the RMT predictions. The expected Porter-Thomas (PT) distribution was considered very early. However, since the widths (amplitudes squared) are measured, the predicted Gaussian distribution for the amplitudes was only qualitatively confirmed. A much more sensitive test was performed by measuring two widths and the relative phase between the two amplitudes. By comparison of the width and amplitude correlations, the Gaussian distribution was confirmed at the 1% level. Following the Bohigas conjecture - that quantum analogs of classically chaotic systems obey RMT - there was an explosion of activity utilizing level statistics in many different quantum systems. In nuclei the focus was verifying the range of applicability of RMT. Of particular interest was the effect of collectivity and of excitation energy on statistical properties. The effect of symmetry breaking on level statistics was examined and early predictions by Dyson were confirmed. The effect of symmetry breaking on the width distribution was also measured for the first time. Although heuristic arguments predicted no change from the PT distribution, experimentally there was a large deviation from the PT prediction. Later theoretical efforts were consistent with this result. The stringent conditions placed on the experiments - for eigenvalue tests the data need to be essentially perfect (few or no missing levels or mis assigned quantum numbers) - has limited the amount of suitable experimental data. The

  1. Hyperdeformed nuclei and the residual pseudo-SU(3) symmetry

    International Nuclear Information System (INIS)

    Dudek, J.; Werner, T.

    1988-01-01

    The author discusses superdeformed and hypothetical hyperdeformed nuclei. Quadrupole deformations characteristic of these types of nuclei are defined. Symmetry features are also discussed. The characteristic cycle dependence of shell structures as functions of the deformation gives rise to chains of the deformed shell closures. Such a chain structure applies to moderately-, super- and hyper-deformed nuclei as well. The resulting total energy calculations give a systematic variation of super- and hyperdeformations with, e.g., increasing N at fixed Z, thus predicting the way nuclei deviate from the simple a:b = 2:1 and a:b = 3:1 symmetries

  2. Structures of exotic nuclei

    International Nuclear Information System (INIS)

    Hamilton, J.H.

    1987-01-01

    Discoveries of many different types of nuclear shape coexistence are being found at both low and high excitation energies throughout the periodic table, as documented in recent reviews. Many new types of shape coexistence have been observed at low excitation energies, for examples bands on more than four different overlapping and coexisting shapes are observed in 185 Au, and competing triaxial and prolate shapes in 71 Se and 176 Pt. Discrete states in super-deformed bands with deformations β 2 ∼ 0.4-0.6, coexisting with other shapes, have been seen to high spin up to 60ℎ in 152 Dy, 132 Ce and 135 Nd. Super-deformed nuclei with N and Z both around 38 and around Z = 38, N ≥ 60. These data led to the discovery of new shell gaps and magic numbers of 38 for N and Z and 60 for N but now for deformed shapes. Marked differences in structure are observed at spins of 6 to 20 in nuclei in this region, which differ by only two protons; for example, 68 Ge and 70 Se. The differences are thought to be related to the competing shell gaps in these nuclei

  3. Elusive active galactic nuclei

    Science.gov (United States)

    Maiolino, R.; Comastri, A.; Gilli, R.; Nagar, N. M.; Bianchi, S.; Böker, T.; Colbert, E.; Krabbe, A.; Marconi, A.; Matt, G.; Salvati, M.

    2003-10-01

    A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically `elusive'. X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtain a first estimate of the fraction of elusive active galactic nuclei (AGN) in local galaxies and to constrain their nature. Our results suggest that elusive AGN have a local density comparable to or even higher than optically classified Seyfert nuclei. Most elusive AGN are heavily absorbed in the X-rays, with gas column densities exceeding 1024 cm-2, suggesting that their peculiar nature is associated with obscuration. It is likely that in elusive AGN the nuclear UV source is completely embedded and the ionizing photons cannot escape, which prevents the formation of a classical narrow-line region. Elusive AGN may contribute significantly to the 30-keV bump of the X-ray background.

  4. Training nuclei detection algorithms with simple annotations

    Directory of Open Access Journals (Sweden)

    Henning Kost

    2017-01-01

    Full Text Available Background: Generating good training datasets is essential for machine learning-based nuclei detection methods. However, creating exhaustive nuclei contour annotations, to derive optimal training data from, is often infeasible. Methods: We compared different approaches for training nuclei detection methods solely based on nucleus center markers. Such markers contain less accurate information, especially with regard to nuclear boundaries, but can be produced much easier and in greater quantities. The approaches use different automated sample extraction methods to derive image positions and class labels from nucleus center markers. In addition, the approaches use different automated sample selection methods to improve the detection quality of the classification algorithm and reduce the run time of the training process. We evaluated the approaches based on a previously published generic nuclei detection algorithm and a set of Ki-67-stained breast cancer images. Results: A Voronoi tessellation-based sample extraction method produced the best performing training sets. However, subsampling of the extracted training samples was crucial. Even simple class balancing improved the detection quality considerably. The incorporation of active learning led to a further increase in detection quality. Conclusions: With appropriate sample extraction and selection methods, nuclei detection algorithms trained on the basis of simple center marker annotations can produce comparable quality to algorithms trained on conventionally created training sets.

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

    Directory of Open Access Journals (Sweden)

    Janet J Y Choi

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

  6. The ocular response to extended wear of a high Dk silicone hydrogel contact lens.

    Science.gov (United States)

    Fonn, Desmond; MacDonald, Karen E; Richter, Doris; Pritchard, Nicola

    2002-05-01

    A four-month extended wear clinical trial was conducted to compare the ocular effects of a high Dk Balafilcon A silicone hydrogel lens and a low Dk HEMA 38.6 per cent H20 soft lens. Twenty-four subjects who were adapted to daily wear of soft lenses wore a high Dk lens in one eye and a low Dk HEMA lens in the other eye for four months on an extended wear basis after one week of daily wear. Thirteen progress evaluations were conducted using standard clinical procedures. Eighteen subjects (75 per cent) completed the study. The high Dk lens induced significantly less bulbar and limbal injection and corneal vascularisation than the low Dk HEMA lens (p Dk lens. A significant increase in myopia was found in the eyes wearing the low Dk HEMA lens (mean = 0.50 D, p Dk lens. Three subjects developed small infiltrates in the high Dk lens wearing eyes and significantly more post-lens debris was observed under the high Dk lens. Six subjects developed papillary conjunctivitis in the eye wearing silicone hydrogel lenses but only two of those were discontinued from the study. No hypoxia-related effects were observed with extended wear of the high Dk Balafilcon A silicone hydrogel lens.

  7. Nuclei transmutation by collisions with fast hadrons and nuclei

    International Nuclear Information System (INIS)

    Strugalski, Z.; Strugalska-Gola, E.; Drzymala, A.

    1998-01-01

    Atomic nuclei change their mass- and charge-numbers if bombarded by fast hadrons and nuclei; the transmutation appears as a complicated process. It proceeds in a definite way - through a few stages or phases. Adequate identification of the nucleons and light nuclear fragments emitted and evaporated in a hadron-nucleus or nucleus-nucleus collisions and in the collision-induced intranuclear reactions allows one to estimate quantitatively the nuclei transmutations in the various stages (phases) of the process

  8. Anomalous carbon nuclei

    International Nuclear Information System (INIS)

    Gasparian, A.P.

    1984-01-01

    Results are presented from a bubble chamber experiment to search for anomalous mean free path (MFP) phenomena for secondary multicharged fragments (Zsub(f)=5 and 6) of the beam carbon nucleus at 4.2 GeV/c per nucleon. A total of 50000 primary interactions of carbon with propane (C 3 H 8 ) were created. Approximately 6000 beam tragments with charges Zsub(f)=5 and 6 were analyzed in detail to find out an anomalous decrease of MFP. The anomaly is observed only for secondary 12 C nuclei

  9. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2001-01-01

    The present collection of letters from JINR, Dubna, contains eight separate records on the interaction of high energy Λ 6 He hypernuclear beams with atomic nuclei, the position-sensitive detector of a high spatial resolution on the basis of a multiwire gas electron multiplier, pseudorapidity hadron density at the LHC energy, high precision laser control of the ATLAS tile-calorimeter module mass production at JINR, a new approach to ECG's features recognition involving neural network, subcriticity of a uranium target enriched in 235 U, beam space charge effects in high-current cyclotron injector CI-5, a homogeneous static gravitational field and the principle of equivalence

  10. Active galactic nuclei

    CERN Document Server

    Beckmann, Volker

    2012-01-01

    This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d

  11. Elementary excitations in nuclei

    International Nuclear Information System (INIS)

    Lemmer, R.H.

    1987-01-01

    The role of elementary quasi-particle and quasi-hole excitations is reviewed in connection with the analysis of data involving high-lying nuclear states. This article includes discussions on: (i) single quasi-hole excitations in pick-up reactions, (ii) the formation of single quasi-hole and quasi-particle excitations (in different nuclei) during transfer reactions, followed by (iii) quasi-particle quasi-hole excitations in the same nucleus that are produced by photon absorption. Finally, the question of photon absorption in the vicinity of the elementary Δ resonance is discussed, where nucleonic as well as nuclear degrees of freedom can be excited

  12. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2000-01-01

    The present collection of letters from JINR, Dubna, contains six separate records on the DELPHI experiment at LEP, the Fermi-surface dynamics of rotating nuclei, production of large samples of the silica dioxide aerogel in the 37-litre autoclave and test of its optical properties, preliminary radiation resource results on scintillating fibers, a new algorithm for the direct transformation method of time to digital with the high time resolution and development and design of analogue read-out electronics for HADES drift chamber system

  13. Cumulation of light nuclei

    International Nuclear Information System (INIS)

    Baldin, A.M.; Bondarev, V.K.; Golovanov, L.B.

    1977-01-01

    Limit fragmentation of light nuclei (deuterium, helium) bombarded with 8,6 GeV/c protons was investigated. Fragments (pions, protons and deuterons) were detected within the emission angle 50-150 deg with regard to primary protons and within the pulse range 150-180 MeV/c. By the kinematics of collision of a primary proton with a target at rest the fragments observed correspond to a target mass upto 3 GeV. Thus, the data obtained correspond to teh cumulation upto the third order

  14. Active galactic nuclei

    CERN Document Server

    Blandford, RD; Woltjer, L

    1990-01-01

    Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory

  15. Fabricating customized hydrogel contact lens

    Science.gov (United States)

    Childs, Andre; Li, Hao; Lewittes, Daniella M.; Dong, Biqin; Liu, Wenzhong; Shu, Xiao; Sun, Cheng; Zhang, Hao F.

    2016-10-01

    Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.

  16. Effect of infrared radiation on the lens

    Directory of Open Access Journals (Sweden)

    Aly Eman

    2011-01-01

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

  17. Daily disposable contact lens prescribing around the world.

    Science.gov (United States)

    Efron, Nathan; Morgan, Philip B; Helland, Magne; Itoi, Motozumi; Jones, Deborah; Nichols, Jason J; van der Worp, Eef; Woods, Craig A

    2010-10-01

    Daily disposable contact lenses were introduced into the market 16 years ago. Data that we have gathered from annual contact lens fitting surveys conducted in Australia, Canada, Japan, The Netherlands, Norway, the UK and the USA between 2000 and 2008 indicates an overall increase in daily disposable lens fitting during this period. Daily disposable lenses are especially popular in Japan, Norway and the UK. There is a trend for these lenses to be fitted on a part-time basis. Males are over-represented in daily disposable lens fitting-a trend that is especially evident in Canada. Daily disposable lens wearers are about two years younger than wearers of reusable lenses in Japan and The Netherlands. The convenience and health benefits of daily disposable lenses are expected to fuel continued growth in this sector. Copyright (c) 2010 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  18. A Correlation of Thin Lens Approximation to Thick Lens Design by Using Coddington Factors in Lens Design and Manufacturing

    OpenAIRE

    FARSAKOĞLU, Ö. Faruk

    2014-01-01

    The effect of Coddington factors on aberration functions has been analysed using thin lens approximation. Minimizing spherical aberrations of singlet lenses using Coddington factors in lens design depending on lens manufacturing is discussed. Notation of lens test plate pairs used in lens manufacturing is also presented in terms of Coddington shape factors.

  19. Effect of contact lens use on Computer Vision Syndrome.

    Science.gov (United States)

    Tauste, Ana; Ronda, Elena; Molina, María-José; Seguí, Mar

    2016-03-01

    To analyse the relationship between Computer Vision Syndrome (CVS) in computer workers and contact lens use, according to lens materials. Cross-sectional study. The study included 426 civil-service office workers, of whom 22% were contact lens wearers. Workers completed the Computer Vision Syndrome Questionnaire (CVS-Q) and provided information on their contact lenses and exposure to video display terminals (VDT) at work. CVS was defined as a CVS-Q score of 6 or more. The covariates were age and sex. Logistic regression was used to calculate the association (crude and adjusted for age and sex) between CVS and individual and work-related factors, and between CVS and contact lens type. Contact lens wearers are more likely to suffer CVS than non-lens wearers, with a prevalence of 65% vs 50%. Workers who wear contact lenses and are exposed to the computer for more than 6 h day(-1) are more likely to suffer CVS than non-lens wearers working at the computer for the same amount of time (aOR = 4.85; 95% CI, 1.25-18.80; p = 0.02). Regular contact lens use increases CVS after 6 h of computer work. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

  20. The effect of compliance on contact lens case contamination.

    Science.gov (United States)

    Tilia, Daniel; Lazon de la Jara, Percy; Zhu, Hua; Naduvilath, Thomas J; Holden, Brien A

    2014-03-01

    To determine the efficacy of written instructions on contact lens case hygiene and to quantify the effect of noncompliance on contact lens case contamination. Data were retrospectively analyzed from 16 prospective, 3-month daily-wear studies during which six commercially available silicone hydrogel contact lenses and seven lens care solutions (LCS) were tested following a similar protocol. Verbal instructions regarding case hygiene (rinse case with LCS, not tap water) were given in nine studies, while the same instructions were given verbally and in written format in seven studies. A survey on contact lens, LCS, and lens case hygiene was completed at 1- and 3-month visits and compliance with case hygiene instructions was determined. Regular contact lens cases were used for 1 month and collected for microbial analysis at the 1- and 3-month visits. The rate of case contamination and the types of microbes contaminating cases were evaluated. Participants given verbal and written instructions were more likely to be compliant with case hygiene instructions than those just given verbal instructions (odds ratio [OR]: 2.19, p hygiene can be improved by effective communication of instructions. Contact lens wearers should be actively discouraged from rinsing contact lens cases with tap water because of the increased risk of GNB contamination.

  1. The Role of Aquaporins in Ocular Lens Homeostasis

    Science.gov (United States)

    Schey, Kevin L.; Petrova, Rosica S.; Gletten, Romell B.; Donaldson, Paul J.

    2017-01-01

    Aquaporins (AQPs), by playing essential roles in the maintenance of ocular lens homeostasis, contribute to the establishment and maintenance of the overall optical properties of the lens over many decades of life. Three aquaporins, AQP0, AQP1 and AQP5, each with distinctly different functional properties, are abundantly and differentially expressed in the different regions of the ocular lens. Furthermore, the diversity of AQP functionality is increased in the absence of protein turnover by age-related modifications to lens AQPs that are proposed to alter AQP function in the different regions of the lens. These regional differences in AQP functionality are proposed to contribute to the generation and directionality of the lens internal microcirculation; a system of circulating ionic and fluid fluxes that delivers nutrients to and removes wastes from the lens faster than could be achieved by passive diffusion alone. In this review, we present how regional differences in lens AQP isoforms potentially contribute to this microcirculation system by highlighting current areas of investigation and emphasizing areas where future work is required. PMID:29231874

  2. Contact lens wear and dry eyes: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Markoulli M

    2017-02-01

    Full Text Available Maria Markoulli, Sailesh Kolanu School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia Abstract: The number of contact lens wearers worldwide has remained relatively stable over the past decade, despite the investment that has gone into contact lens technology. This is largely because 10%–50% of wearers dropout of contact lens wear within 3 years of commencement; the most common reason cited being contact lens discomfort (CLD. Of the symptoms reported, sensation of dry eye is the most common. Given the outcome of reduced wearing time, increased chair time, and ultimate contact lens discontinuation, the challenge is to identify the warning signs of CLD early on. Clinically detectable changes such as conjunctival staining, conjunctival indentation, conjunctival epithelial flap formation, lid wiper epitheliopathy, Demodex blepharitis, and meibomian gland dysfunction have been linked to CLD, highlighting the need to perform regular aftercare visits to identify these changes. At a cellular level, conjunctival metaplasia and reduced goblet cell density have been linked to CLD, leading to a downstream effect on the tear film breakup time of contact lens wearers. These factors suggest a strong link between CLD and friction, raising the need to target this as a means of minimizing CLD. The purpose of this review is to identify the clinical signs that relate to CLD as a means of earlier detection and management in order to combat contact lens dropout. Keywords: contact lens discomfort, dry eye disease, lid wiper epitheliopathy, tear film biomarkers, meibomian gland dysfunction

  3. Exotic nuclei and radioactive beams

    International Nuclear Information System (INIS)

    Chomaz, P.

    1996-01-01

    The Nuclei called exotic are all the nuclei that it is necessary to recreate in laboratory to study them. Their life time is too short -in relation to earth age- for it remains enough on earth. The researchers are going to have at their s disposal at GANIL (Caen) with the S.P.I.R.A.L. project, exotic nuclei beams and will study new kinds of nuclear reactions to better understand the atom nucleus. (N.C.). 2 refs., 9 figs

  4. Isolation of Nuclei and Nucleoli.

    Science.gov (United States)

    Pendle, Alison F; Shaw, Peter J

    2017-01-01

    Here we describe methods for producing nuclei from Arabidopsis suspension cultures or root tips of Arabidopsis, wheat, or pea. These methods could be adapted for other species and cell types. The resulting nuclei can be further purified for use in biochemical or proteomic studies, or can be used for microscopy. We also describe how the nuclei can be used to obtain a preparation of nucleoli.

  5. Stability of superheavy nuclei

    Science.gov (United States)

    Pomorski, K.; Nerlo-Pomorska, B.; Bartel, J.; Schmitt, C.

    2018-03-01

    The potential-energy surfaces of an extended set of heavy and superheavy even-even nuclei with 92 ≤Z ≤126 and isospins 40 ≤N -Z ≤74 are evaluated within the recently developed Fourier shape parametrization. Ground-state and decay properties are studied for 324 different even-even isotopes in a four-dimensional deformation space, defined by nonaxiality, quadrupole, octupole, and hexadecapole degrees of freedom. Nuclear deformation energies are evaluated in the framework of the macroscopic-microscopic approach, with the Lublin-Strasbourg drop model and a Yukawa-folded mean-field potential. The evolution of the ground-state equilibrium shape (and possible isomeric, metastable states) is studied as a function of Z and N . α -decay Q values and half-lives, as well as fission-barrier heights, are deduced. In order to understand the transition from asymmetric to symmetric fission along the Fm isotopic chain, the properties of all identified fission paths are investigated. Good agreement is found with experimental data wherever available. New interesting features about the population of different fission modes for nuclei beyond Fm are predicted.

  6. Cluster structures in light nuclei

    International Nuclear Information System (INIS)

    Horiuchi, H.

    2000-01-01

    Complete text of publication follows. Clustering in neutron-rich nuclei is discussed. To understand the novel features (1,2,3) of the clustering in neutron-rich nuclei, the basic features of the clustering in stable nuclei (4) are briefly reviewed. In neutron-rich nuclei, the requirement of the stability of clusters is questioned and the threshold rule is no more obeyed. Examples of clustering in Be and B isotopes (4,5) are discussed in some detail. Possible existence of novel type of clustering near neutron dripline is suggested (1). (author)

  7. Particle-rotation coupling in atomic nuclei

    International Nuclear Information System (INIS)

    Almberger, J.

    1980-01-01

    Recently an increased interest in the rotational nuclei has been spurred by the new experimental high-spin activities and by the possibilities for lower spins to interpret an impressive amount of experimental data by some comparatively simple model calculations. The author discusses the particle modes of excitation for rotational nuclei in the pairing regime where some puzzles in the theoretical description remain to be resolved. A model comparison is made between the particle-rotor and cranking models which have different definitions of the collective rotation. The cranking model is found to imply a smaller value of the quasiparticle spin alignment than the particle-rotor model. Rotational spectra for both even and odd nuclei are investigated with the use of the many-BCS-quasiparticles plus rotor model. This model gives an accurate description of the ground and S-bands in many even-even rare-earth nuclei. However, the discrepancies for odd-A nuclei between theory and experiments point to the importance of additional physical components. Therefore the rotationally induced quadrupole pair field is considered. This field has an effect on the low spin states in odd-A nuclei, but is not sufficient to account for the experimental data. Another topic considered is the interaction matrix element in crossings for given spin between quasiparticle rotational bands. The matrix elements are found to oscillate as a function of the number of particles, thereby influencing the sharpness of the backbending. Finally the low-spin continuation of the S-band is studied and it is shown that such states can be populated selectively by means of one-particle pickup reactions involving high angular momentum transfer. (Auth.)

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

    Science.gov (United States)

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

    2008-10-01

    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 transmission studies, biofilms of Staphylococcus aureus 835 or Pseudomonas aeruginosa no. 3 were grown on lens storage cases and incubated with a contact lens in different multipurpose lens care solutions (Opti-Free(R)Express(R), ReNu(R) MultiPlus(R), and SoloCare Aquatrade mark) or 0.9% NaCl. In addition, planktonic bacteria were directly suspended in multipurpose solutions and their killing efficacies were determined. The numbers of transmitted live and dead bacteria on the lenses were measured using a combination of plate counting and fluorescence microscopy. The highest killing efficacies were shown by Opti-Free(R) Express(R) for planktonic as well as for biofilm bacteria. Silver impregnation of lens cases in combination with the prescribed solution increased the killing efficacy for P. aeruginosa in biofilms, whereas effects for S. aureus were minor. Lowest numbers of live and dead bacteria were transmitted to a lens in Opti-Free(R) Express(R) multipurpose solution, with no significant differences between lens types and no effects of silver impregnation. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008. (c) 2008 Wiley Periodicals, Inc.

  9. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2001-01-01

    The present collection of letters from JINR, Dubna, contains ten separate records on the monochromatic neutrinos from massive fourth generation neutrino annihilation in the Sun and Earth, solar neutrino results from SAGE, the present and future oscillation experiments at reactors, as well as on the possibilities to test the LSND parameters at reactors, the energy spectrum of reactor antineutrinos and searches for new physics (recent developments), angular distribution of radiative gamma quanta in radiative beta decay of neutrons, an 37 Ar based neutrino source for calibration of the iodine solar neutrino detector, detector LENS as a new tool for solar neutrino spectroscopy, limits on different Majoron decay modes of 100 Mo, 116 Cd, 82 Se, and 96 Zr for neutrinoless double beta decays in the NEMO-2 experiment as well as on the search for 76 Ge and 150 Nd double beta decay to excited states

  10. Level structures in Yb nuclei far from stable nuclei

    International Nuclear Information System (INIS)

    Hashizume, Akira

    1982-01-01

    Applying n-γ, γ-γ coincidence techniques, the excited levels in 158 Yb and in 157 Yb nuclei were studied. Stress is placed ona neutron detection technique to assign (HI,xn) reactions which produce the nuclei far from β stability line. (author)

  11. Electron scattering off nuclei

    International Nuclear Information System (INIS)

    Gattone, A.O.

    1989-01-01

    Two recently developed aspects related to the scattering of electrons off nuclei are presented. On the one hand, a model is introduced which emphasizes the relativistic aspects of the problem in the impulse approximation, by demanding strict maintenance of the algebra of the Poincare group. On the other hand, the second model aims at a more sophisticated description of the nuclear response in the case of collective excitations. Basically, it utilizes the RPA formalism with a new development which enables a more careful treatment of the states in the continuum as is the case for the giant resonances. Applications of both models to the description of elastic scattering, inelastic scattering to discrete levels, giant resonances and the quasi-elastic region are discussed. (Author) [es

  12. Antideuteron annihilation on nuclei

    International Nuclear Information System (INIS)

    Cugnon, J.

    1992-01-01

    An investigation of antideuteron annihilation on nuclei within an intranuclear cascade (INC) model is presented. Two models are set up to describe the annihilation itself, which either implies the antideuteron as a whole and occurs at a single point, or which may be considered as two independent nucleon-antinucleon annihilation occurring at different points and different times. Particular attention is paid to the energy transferred from the pions issued from the annihilation to the nuclear system and to the possibility of having a multifragmentation of the target. The latter feature is investigated within a percolation model. The pion distribution and the energy distribution are also discussed. Predictions of proton multiplicity distributions are compared with experiment. (orig.)

  13. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2002-01-01

    The present collection of letters from JINR, Dubna, contains ten separate records on Wien filter using in exploring on low-energy radioactive nuclei, memory effects in dissipative nucleus-nucleus collision, topological charge and topological susceptibility in connection with translation and gauge invariance, solutions of the multitime Dirac equation, the maximum entropy technique. System's statistical description, the charged conductor inside dielectric. Solution of boundary condition by means of auxiliary charges and the method of linear algebraic equations, optical constants of the TGS single crystal irradiated by power pulsed electron beam, interatomic pair potential and n-e amplitude from slow neutron scattering by noble gases, the two-coordinate multiwire proportional chamber of the high spatial resolution and neutron drip line in the region of O-Mg isotopes

  14. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2000-01-01

    The present collection of letters from JINR, Dubna, contains seven separate records on the integral representation for structure functions and target mass effects, multiscale properties of DNA primary structure including cross-scale correlations, dissipative evolution of the elementary act, the fine structure of the M T =1 Gamow-Teller resonance in 147g Tb→ 147 Gd β + /EC decay, the behaviour of the TVO temperature sensors in the magnetic fields, a fast method for searching for tracks in multilayer drift chambers of HADES spectrometer, a novel approach to particle track etching including surfactant enhanced control of pore morphology, azimuthal correlations of secondary particles in 32 S induced interactions with Ag(Br) nuclei at 4.5 GeV/ c/ nucleon

  15. Pulsars: gigantic nuclei

    International Nuclear Information System (INIS)

    Xu, Renxin

    2011-01-01

    What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the gigantic nucleus speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction. (author)

  16. Clusters in nuclei

    CERN Document Server

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  17. Pion production in nuclei

    International Nuclear Information System (INIS)

    Afnan, I.R.; Thomas, A.W.

    1976-01-01

    A method has been suggested for relating μ-capture in nuclei to pion absorption through partially conserved axial vector current hypothesis. The success of the method relies heavily on the knowledge of the pion absorption amplitude at a momentum transfer equal to the μ-meson mass. That is we need to know the pion absorption amplitude off the mass-shell. The simplest nucleus for which this suggestion can be examined is μ-capture in deuterium. The Koltum-Reitan model is used to determine the pion absorption amplitude off the mass shell. In particular the senstivity of this off-mass-shell extrapolution to details of the N-N interaction is studied. (author)

  18. Collective excitations in nuclei

    International Nuclear Information System (INIS)

    Chomaz, Ph.

    1998-01-01

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors)

  19. IBA in deformed nuclei

    International Nuclear Information System (INIS)

    Casten, R.F.; Warner, D.D.

    1982-01-01

    The structure and characteristic properties and predictions of the IBA in deformed nuclei are reviewed, and compared with experiment, in particular for 168 Er. Overall, excellent agreement, with a minimum of free parameters (in effect, two, neglecting scale factors on energy differences), was obtained. A particularly surprising, and unavoidable, prediction is that of strong β → γ transitions, a feature characteristically absent in the geometrical model, but manifest empirically. Some discrepancies were also noted, principally for the K=4 excitation, and the detailed magnitudes of some specific B(E2) values. Considerable attention is paid to analyzing the structure of the IBA states and their relation to geometric models. The bandmixing formalism was studied to interpret both the aforementioned discrepancies and the origin of the β → γ transitions. The IBA states, extremely complex in the usual SU(5) basis, are transformed to the SU(3) basis, as is the interaction Hamiltonian. The IBA wave functions appear with much simplified structure in this way as does the structure of the associated B(E2) values. The nature of the symmetry breaking of SU(3) for actual deformed nuclei is seen to be predominantly ΔK=0 mixing. A modified, and more consistent, formalism for the IBA-1 is introduced which is simpler, has fewer free parameters (in effect, one, neglecting scale factors on energy differences), is in at least as good agreement with experiment as the earlier formalism, contains a special case of the 0(6) limit which corresponds to that known empirically, and appears to have a close relationship to the IBA-2. The new formalism facilitates the construction of contour plots of various observables (e.g., energy or B(E2) ratios) as functions of N and chi/sub Q/ which allow the parameter-free discussion of qualitative trajectories or systematics

  20. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors) 304 refs., 53 figs., 5 tabs.

  1. Spectroscopy of heavy fissionable nuclei

    Indian Academy of Sciences (India)

    2015-08-05

    Aug 5, 2015 ... Nuclei in the actinide chain and beyond are prone to fission owing to ... mass nuclei are typically more difficult, because the intensity is .... j15/2 neutron alignments in a region where shell stablization effects are crucial.

  2. Characteristics of the thick, compound refractive lens

    International Nuclear Information System (INIS)

    Pantell, Richard H.; Feinstein, Joseph; Beguiristain, H. Raul; Piestrup, Melvin A.; Gary, Charles K.; Cremer, Jay T.

    2003-01-01

    A compound refractive lens (CRL), consisting of a series of N closely spaced lens elements each of which contributes a small fraction of the total focusing, can be used to focus x rays or neutrons. The thickness of a CRL can be comparable to its focal length, whereupon a thick-lens analysis must be performed. In contrast with the conventional optical lens, where the ray inside the lens follows a straight line, the ray inside the CRL is continually changing direction because of the multiple refracting surfaces. Thus the matrix representation for the thick CRL is quite different from that for the thick optical lens. Principal planes can be defined such that the thick-lens matrix can be converted to that of a thin lens. For a thick lens the focal length is greater than for a thin lens with the same lens curvature, but this lengthening effect is less for the CRL than for the conventional optical lens

  3. Surgical treatment of hereditary lens subluxations.

    Science.gov (United States)

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

    2002-01-01

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

  4. Crystalline lens thickness determines the perceived chromatic difference in magnification.

    Science.gov (United States)

    Chen, Yun; Schaeffel, Frank

    2014-03-01

    Since the origin of the high interindividual variability of the chromatic difference in retinal image magnification (CDM) in the human eye is not well understood, optical parameters that might determine its magnitude were studied in 21 healthy subjects with ages ranging from 21 to 58 years. Two psychophysical procedures were used to quantify CDM. They produced highly correlated results. First, a red and a blue square, presented on a black screen, had to be matched in size by the subjects with their right eyes. Second, a filled red and blue square, flickering on top of each other at 2 Hz, had to be adjusted in perceived brightness and then in size to minimize the impression of flicker. CDM varied widely among subjects from 0.0% to 3.6%. Biometric ocular parameters were measured with low coherence interferometry and crystalline lens tilt and decentration with a custom-built Purkinjemeter. Correlations were studied between CDM and corneal power, anterior chamber depth, lens thickness, lens tilt and lens decentration, and vitreous chamber depths. Lens thickness was found significantly correlated with CDM and accounted for 64% of its variance. Vertical lens tilt and decentration were also significantly correlated. It was also found that CDM increased by 3.5% per year, and part of this change can be attributed to the age-related increase in lens thickness.

  5. Problem of ''deformed'' superheavy nuclei

    International Nuclear Information System (INIS)

    Sobiczewski, A.; Patyk, Z.; Muntian, I.

    2000-08-01

    Problem of experimental confirmation of deformed shapes of superheavy nuclei situated in the neighbourhood of 270 Hs is discussed. Measurement of the energy E 2+ of the lowest 2+ state in even-even species of these nuclei is considered as a method for this confirmation. The energy is calculated in the cranking approximation for heavy and superheavy nuclei. The branching ratio p 2+ /p 0+ between α decay of a nucleus to this lowest 2+ state and to the ground state 0+ of its daughter is also calculated for these nuclei. The results indicate that a measurement of the energy E 2+ for some superheavy nuclei by electron or α spectroscopy is a promising method for the confirmation of their deformed shapes. (orig.)

  6. Quarks in Few Body Nuclei

    Directory of Open Access Journals (Sweden)

    Holt Roy J.

    2016-01-01

    Full Text Available Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

  7. An image processing pipeline to detect and segment nuclei in muscle fiber microscopic images.

    Science.gov (United States)

    Guo, Yanen; Xu, Xiaoyin; Wang, Yuanyuan; Wang, Yaming; Xia, Shunren; Yang, Zhong

    2014-08-01

    Muscle fiber images play an important role in the medical diagnosis and treatment of many muscular diseases. The number of nuclei in skeletal muscle fiber images is a key bio-marker of the diagnosis of muscular dystrophy. In nuclei segmentation one primary challenge is to correctly separate the clustered nuclei. In this article, we developed an image processing pipeline to automatically detect, segment, and analyze nuclei in microscopic image of muscle fibers. The pipeline consists of image pre-processing, identification of isolated nuclei, identification and segmentation of clustered nuclei, and quantitative analysis. Nuclei are initially extracted from background by using local Otsu's threshold. Based on analysis of morphological features of the isolated nuclei, including their areas, compactness, and major axis lengths, a Bayesian network is trained and applied to identify isolated nuclei from clustered nuclei and artifacts in all the images. Then a two-step refined watershed algorithm is applied to segment clustered nuclei. After segmentation, the nuclei can be quantified for statistical analysis. Comparing the segmented results with those of manual analysis and an existing technique, we find that our proposed image processing pipeline achieves good performance with high accuracy and precision. The presented image processing pipeline can therefore help biologists increase their throughput and objectivity in analyzing large numbers of nuclei in muscle fiber images. © 2014 Wiley Periodicals, Inc.

  8. Lens protection from ionizing radiaton damage with gammaphos

    International Nuclear Information System (INIS)

    Rozsival, P.; Obenberger, J.; Zaydlar, K.

    1986-01-01

    Intramuscular administration of gammaphos prior to irradiation with 60 Co in rabbits significantly reduced the weight increase in the lens after irradiation and delayed it by 8 weeks. No marked opacity of lens was observed even after 24 weeks. The decline in the dry matter content in the irradiated lenses was retarded by 8 weeks and the difference between the protected and unprotected animals was statistically significant. The rise in water content in the lenses after irradiation was also delayed by 8 weeks by the administration of gammaphos prior to irradiation. Gammaphos delays the development of changes in the lens after irradiation. (author) 4 figs., 11 refs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

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

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

    International Nuclear Information System (INIS)

    Rehani, M.

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    Park, J.

    2015-01-01

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

  13. Influence of Ice Nuclei Parameterization Schemes on the Hail Process

    Directory of Open Access Journals (Sweden)

    Xiaoli Liu

    2018-01-01

    Full Text Available Ice nuclei are very important factors as they significantly affect the development and evolvement of convective clouds such as hail clouds. In this study, numerical simulations of hail processes in the Zhejiang Province were conducted using a mesoscale numerical model (WRF v3.4. The effects of six ice nuclei parameterization schemes on the macroscopic and microscopic structures of hail clouds were compared. The effect of the ice nuclei concentration on ground hailfall is stronger than that on ground rainfall. There were significant spatiotemporal, intensity, and distribution differences in hailfall. Changes in the ice nuclei concentration caused different changes in hydrometeors and directly affected the ice crystals, and, hence, the spatiotemporal distribution of other hydrometeors and the thermodynamic structure of clouds. An increased ice nuclei concentration raises the initial concentration of ice crystals with higher mixing ratio. In the developing and early maturation stages of hail cloud, a larger number of ice crystals competed for water vapor with increasing ice nuclei concentration. This effect prevents ice crystals from maturing into snow particles and inhibits the formation and growth of hail embryos. During later maturation stages, updraft in the cloud intensified and more supercooled water was transported above the 0°C level, benefitting the production and growth of hail particles. An increased ice nuclei concentration therefore favors the formation of hail.

  14. Characteristics of disintegration of different emulsion nuclei by ...

    Indian Academy of Sciences (India)

    2Department of Applied Science (Physics), Vidya College of Engineering, ... ded nuclei, offers a great advantage to study the nuclear collisions of the same projectile ... This will also allow us to have an increased statistics of the sample.

  15. Cytokine changes in tears and relationship to contact lens discomfort.

    Science.gov (United States)

    Willcox, Mark D P; Zhao, Zhenjun; Naduvilath, Thomas; Lazon de la Jara, Percy

    2015-01-01

    To determine the reproducibility of a multiplex bead assay for measuring cytokines in tears and correlations between ocular discomfort with or without contact lens wear and the concentration of cytokines in tears. Ninety participants (divided into two groups) were enrolled in this prospective study. They were asked to rate their ocular comfort and collect their tears in the morning and just before sleep for 10 days with or without contact lenses. The participants collected their tears using a glass microcapillary tube for both stages. Galyfilcon A lenses were worn on a daily disposable basis during the contact lens stage, and comfort scores and tears were collected before lens insertion and prior to lens removal at the end of the day. Tears were analyzed for cytokine concentrations using a 27-plex multibead assay. Correlations were sought between cytokine concentrations and comfort. There was a significant (p-0.5 Log pg/ml, p-0.2 Log pg/ml, ptears was correlated to ocular comfort, but this was not changed by contact lens wear. Ocular comfort during the day is magnified by contact lens wear. However, the increase in the change in comfort during lens wear was not associated with changes in 15 cytokines in the tear film.

  16. Numerical studies on the ramped density plasma lens

    International Nuclear Information System (INIS)

    Williams, R.L.; Katsouleas, T.

    1992-01-01

    We consider the so-called adiabatic plasma lens when the plasma density is ramped too quickly to be considered adiabatic. The lens length can be much shorter in such a case, but the final spot size is shown to be larger by a factor of √1+α 2 than for a slowly ramped plasma lens with the same initial and final density (where α=-β'/2 is proportional to the plasma density gradient). We find that the final spot size is the same whether or not the Courant-Snyder parameters of the beam (α and β) are matched to the lens. However, matched beams allow the plasma density to be lower while unmatched beams allow the lens to be shorter (for the same α and for the same final to initial plasma density ratio). Finally, we find that a smaller spot size can be obtained for a given lens length and density ratio by starting at smaller α and increasing α along the lens

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

    Science.gov (United States)

    Lanchares, Elena; Navarro, Rafael; Calvo, Begoña

    2012-01-01

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

  18. K-bar-mesic nuclei

    International Nuclear Information System (INIS)

    Dote, Akinobu; Akaishi, Yoshinori; Yamazaki, Toshimitsu

    2005-01-01

    New nuclei 'K-bar-Mesic Nuclei' having the strangeness are described. At first it is shown that the strongly attractive nature of K-bar N interaction is reasoned inductively from consideration of the relation between Kaonic hydrogen atom and Λ (1405) which is an excited state of hyperon Λ. The K-bar N interactions are reviewed and summarized into three categories: 1. Phenomenological approach with density dependent K-bar N interaction (DD), relativistic mean field (RMF) approach, and hybrid of them (RMF+DD). 2. Boson exchange model. 3. Chiral SU(3) theory. The investigation of some light K-bar-nuclei by Akaishi and Yamazaki using phenomenological K-bar N interaction is explained in detail. Studies by antisymmetrized molecular dynamics (AMD) approach are also presented. From these theoretical researches, the following feature of K-bar-mesic nuclei are revealed: 1) Ground state is discrete and bound by 100 MeV or more. 2) Density is very high in side the K-bar-mesic nuclei. 3) Strange structures develop which are not seen in ordinary nuclei. Finally some recent experiments to explore K-bar-mesic nuclei are reviewed. (S. Funahashi)

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

    Science.gov (United States)

    Delamere, Nicholas A.; Tamiya, Shigeo

    2009-01-01

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

  20. Monopole transitions in hot nuclei

    International Nuclear Information System (INIS)

    Sujkowski, Z.

    1994-01-01

    Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs

  1. Monopole transitions in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sujkowski, Z. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

    1994-12-31

    Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs.

  2. Electron scattering for exotic nuclei

    International Nuclear Information System (INIS)

    Suda, T.

    2013-01-01

    An electron scattering facility is under construction in RIKEN RI Beam Factory, Japan, which is dedicated to the structure studies of short-lived nuclei. This is the world's first and currently only facility of its type. The construction is nearly completed, and the first electron scattering experiment off short-lived nuclei will be carried out in the beginning of next year. The charge density distributions of short-lived nuclei will be precisely determined by elastic electron scattering for the first time. Physics pursued at this facility including future perspectives are explained

  3. Cavitation inception from bubble nuclei

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2015-01-01

    , and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid....... The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model...

  4. Gluon density in nuclei

    International Nuclear Information System (INIS)

    Ayala, A.L.

    1996-01-01

    In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab

  5. Supersymmetry in nuclei

    CERN Document Server

    Jolie, J

    2002-01-01

    All the elementary particles that make up matter (as do quarks, electrons, neutrinos....) are fermions, the particles that convey the fundamental interactions (as do photons, gluons, W, Z...) are bosons. Composite particles are either bosons, or fermions according to the number of fermions they contain: if this number is even the particle is a boson, otherwise it is a fermion. According to this rule a proton is a fermion and the He sup 4 atom is a boson. Symmetry plays an important role in the standard model, a symmetry is a transformation that connect bosons with other bosons or fermions with other fermions. Supersymmetry associates a boson with a fermion or a fermion with a boson, in fact supersymmetry connects nuclei that are not generally considered as akin. Supersymmetry has just been observed in low energy levels of Gold sup 1 sup 9 sup 5 sup - sup 1 sup 9 sup 6 and Platinum sup 1 sup 9 sup 4 - sup 1 sup 9 sup 5 , it means that the description of these energy levels is simplified and can be made by a co...

  6. Supersymmetry in nuclei

    International Nuclear Information System (INIS)

    Jolie, J.

    2002-01-01

    All the elementary particles that make up matter (as do quarks, electrons, neutrinos....) are fermions, the particles that convey the fundamental interactions (as do photons, gluons, W, Z...) are bosons. Composite particles are either bosons, or fermions according to the number of fermions they contain: if this number is even the particle is a boson, otherwise it is a fermion. According to this rule a proton is a fermion and the He 4 atom is a boson. Symmetry plays an important role in the standard model, a symmetry is a transformation that connect bosons with other bosons or fermions with other fermions. Supersymmetry associates a boson with a fermion or a fermion with a boson, in fact supersymmetry connects nuclei that are not generally considered as akin. Supersymmetry has just been observed in low energy levels of Gold 195-196 and Platinum 194 - 195 , it means that the description of these energy levels is simplified and can be made by a common set of quantum numbers. (A.C.)

  7. Photon interactions with nuclei

    International Nuclear Information System (INIS)

    Thornton, S.T.; Sealock, R.M.

    1989-01-01

    This document is a progress report for DOE Grant No. FG05-89ER40501, A000. The grant began March, 1989. Our primary research effort has been expended at the LEGS project at Brookhaven National Laboratory. This report will summarize our present research effort at LEGS as well as data analysis and publications from previous experiments performed at SLAC. In addition the principal investigators are heavily involved in the CLAS collaboration in Hall B at CEBAF. We have submitted several letters of intent and proposals and have made commitments to construct experimental equipment for CEBAF. We expect our primary experimental effort to continue at LEGS until CEBAF becomes operational. This report will be divided into separate sections describing our progress at LEGS, SLAC, and CEBAF. We will also discuss our significant efforts in the education and training of both undergraduate and graduate students. Photon detectors are described as well as experiments on delta deformation in nuclei of quasielastic scattering and excitation of the delta by 4 He(e,e')

  8. Parity violation in nuclei

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1980-01-01

    A summary of parity violating effects in nuclei is given. Thanks to vigorous experimental and theoretical effort, it now appears that a reasonably well-defined value for the weak isovector π-nucleon coupling constant can be obtained. There is one major uncertainty in the analysis, namely the M2/E1 mixing ratio for the 2.79 MeV transition in 21 Ne. This quantity is virtually impossible to calculate reliably and must be measured. If it turns out to be much larger than 1, then a null result in 21 Ne is expected no matter what the weak interaction, so an experimental determination is urgently needed. The most promising approach is perhaps a measurement of the pair internal conversion coefficient. Of course, a direct measurement of a pure isovector case is highly desirable, and it is to be hoped that the four ΔT = 1 experiments will be pushed still further, and that improved calculations will be made for the 6 Li case. Nuclear parity violation seems to be rapidly approaching an interesting and useful synthesis

  9. Fragmentation of relativistic nuclei

    International Nuclear Information System (INIS)

    Cork, B.

    1975-06-01

    Nuclei with energies of several GeV/n interact with hadrons and produce fragments that encompass the fields of nuclear physics, meson physics, and particle physics. Experimental results are now available to explore problems in nuclear physics such as the validity of the shell model to explain the momentum distribution of fragments, the contribution of giant dipole resonances to fragment production cross sections, the effective Coulomb barrier, and nuclear temperatures. A new approach to meson physics is possible by exploring the nucleon charge-exchange process. Particle physics problems are explored by measuring the energy and target dependence of isotope production cross sections, thus determining if limiting fragmentation and target factorization are valid, and measuring total cross sections to determine if the factorization relation, sigma/sub AB/ 2 = sigma/sub AA/ . sigma/sub BB/, is violated. Also, new experiments have been done to measure the angular distribution of fragments that could be explained as nuclear shock waves, and to explore for ultradense matter produced by very heavy ions incident on heavy atoms. (12 figures, 2 tables)

  10. Symmetries in nuclei

    International Nuclear Information System (INIS)

    Arima, A.

    2003-01-01

    (1) There are symmetries in nature, and the concept of symmetry has been used in art and architecture. The symmetry is evaluated high in the European culture. In China, the symmetry is broken in the paintings but it is valued in the architecture. In Japan, however, the symmetry has been broken everywhere. The serious and interesting question is why these differences happens? (2) In this lecture, I reviewed from the very beginning the importance of the rotational symmetry in quantum mechanics. I am sorry to be too fundamental for specialists of nuclear physics. But for people who do not use these theories, I think that you could understand the mathematical aspects of quantum mechanics and the relation between the angular momentum and the rotational symmetry. (3) To the specialists of nuclear physics, I talked about my idea as follows: dynamical treatment of collective motions in nuclei by IBM, especially the meaning of the degeneracy observed in the rotation bands top of γ vibration and β vibration, and the origin of pseudo-spin symmetry. Namely, if there is a symmetry, a degeneracy occurs. Conversely, if there is a degeneracy, there must be a symmetry. I discussed some details of the observed evidence and this correspondence is my strong belief in physics. (author)

  11. Collective excitations in nuclei

    International Nuclear Information System (INIS)

    Chomaz, Ph.

    1997-01-01

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author)

  12. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph

    1997-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author) 270 refs.

  13. Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus)

    DEFF Research Database (Denmark)

    Nielsen, Julius; Hedeholm, Rasmus B.; Heinemeier, Jan

    2016-01-01

    The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas, grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life span well beyond those of other vertebrates. Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm i...

  14. Wedged multilayer Laue lens

    International Nuclear Information System (INIS)

    Conley, Ray; Liu Chian; Qian Jun; Kewish, Cameron M.; Macrander, Albert T.; Yan Hanfei; Maser, Joerg; Kang, Hyon Chol; Stephenson, G. Brian

    2008-01-01

    A multilayer Laue lens (MLL) is an x-ray focusing optic fabricated from a multilayer structure consisting of thousands of layers of two different materials produced by thin-film deposition. The sequence of layer thicknesses is controlled to satisfy the Fresnel zone plate law and the multilayer is sectioned to form the optic. An improved MLL geometry can be created by growing each layer with an in-plane thickness gradient to form a wedge, so that every interface makes the correct angle with the incident beam for symmetric Bragg diffraction. The ultimate hard x-ray focusing performance of a wedged MLL has been predicted to be significantly better than that of a nonwedged MLL, giving subnanometer resolution with high efficiency. Here, we describe a method to deposit the multilayer structure needed for an ideal wedged MLL and report our initial deposition results to produce these structures

  15. Resonant Tidal Disruption in Galactic Nuclei

    OpenAIRE

    Rauch, Kevin P.; Ingalls, Brian

    1997-01-01

    It has recently been shown that the rate of angular momentum relaxation in nearly-Keplerian star clusters is greatly increased by a process termed resonant relaxation (Rauch & Tremaine 1996), who also argued that tidal disruption of stars in galactic nuclei containing massive black holes could be noticeably enhanced by this process. We describe here the results of numerical simulations of resonant tidal disruption which quantitatively test the predictions made by Rauch & Tremaine. The simulat...

  16. Dynamic polarization of radioactive nuclei

    International Nuclear Information System (INIS)

    Kiselev, Yu.F.; Lyuboshits, V.L.; )

    2001-01-01

    Radioactive nuclei, embedded into a frozen polarized proton target, atr proposed to polarize by means of some dynamic polarization methods. Angular distributions of γ-quanta emitted ny 22 Na(3 + ) in the cascade β-γ-radiation are calculated. It is shown that this distribution does not depend on the spin temperature sing at the Boltzmann distribution of populations among the Zeeman magnetic substates, whereas the tensor polarization of quadrupole nuclei, placed in the electric field of the crystal, causes the considerable sing dependence. The new method promises wide opportunities for the magnetic structure investigations as well as for the study of spin-spin interaction dynamics of rare nuclei in dielectrics. Physical-technical advantages and disadvantages of the given method are discussed for the polarization of heavy nuclei in the on-line implantation mode [ru

  17. The delta in nuclei. Experiments

    International Nuclear Information System (INIS)

    Roy-Stephan, M.

    1989-01-01

    Experimental aspects of the Δ excitation will be presented. The Δ excitation in nuclei will be compared to the free Δ excitation. Various probes will be reviewed and their specific features will be underlined [fr

  18. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... Research Center for Electron-Photon Science, Tohoku University, 1-2-1 ... nuclei precisely determined by elastic scattering [1]. .... In order to fulfill these requirements, a window-frame shaped dipole magnet with a gap.

  19. Compliance among soft contact lens wearers.

    Science.gov (United States)

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

    2014-12-01

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

  20. Collisions between complex atomic nuclei

    International Nuclear Information System (INIS)

    Vaagen, J. S.

    1977-08-01

    The use of heavy ion accelerators in the study of nuclear structure and states is reviewed. The reactions discussed are the quasielastic reactions in which small amounts of energy and few particles are exchanged between the colliding nuclei. The development of heavy ion accelerators is also discussed, as well as detection equipment. Exotic phenomena, principally the possible existence of superheavy nuclei, are also treated. (JIW)

  1. Particles and nuclei in PANIC

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-07-15

    PANIC is the triennal International Conference on Particles and Nuclei, and judging from the latest PANIC, held in Kyoto from 20-24 April there is no need for panic yet. Faced with two pictures – one of nuclei described in nucleon and meson terms, and another of nucleons containing quarks and gluons – physicists are intrigued to know what new insights from the quark level can tell us about nuclear physics, or vice versa.

  2. Particles and nuclei in PANIC

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    PANIC is the triennal International Conference on Particles and Nuclei, and judging from the latest PANIC, held in Kyoto from 20-24 April there is no need for panic yet. Faced with two pictures – one of nuclei described in nucleon and meson terms, and another of nucleons containing quarks and gluons – physicists are intrigued to know what new insights from the quark level can tell us about nuclear physics, or vice versa

  3. RADIO VARIABILITY IN SEYFERT NUCLEI

    International Nuclear Information System (INIS)

    Mundell, C. G.; Ferruit, P.; Nagar, N.; Wilson, A. S.

    2009-01-01

    Comparison of 8.4 GHz radio images of a sample of eleven, early-type Seyfert galaxies with previous observations reveals possible variation in the nuclear radio flux density in five of them over a seven year period. Four Seyferts (NGC 2110, NGC 3081, MCG -6-30-15, and NGC 5273) show a decline in their 8.4 GHz nuclear flux density between 1992 and 1999, while one (NGC 4117) shows an increase; the flux densities of the remaining six Seyferts (Mrk 607, NGC 1386, Mrk 620, NGC 3516, NGC 4968, and NGC 7465) have remained constant over this period. New images of MCG -5-23-16 are also presented. We find no correlation between radio variability and nuclear radio luminosity or Seyfert nuclear type, although the sample is small and dominated by type 2 Seyferts. Instead, a possible correlation between the presence of nuclear radio variability and the absence of hundred parsec-scale radio emission is seen, with four out of five marginally resolved or unresolved nuclei showing a change in nuclear flux density, while five out of six extended sources show no nuclear variability despite having unresolved nuclear sources. NGC 2110 is the only source in our sample with significant extended radio structure and strong nuclear variability (∼38% decline in nuclear flux density over seven years). The observed nuclear flux variability indicates significant changes are likely to have occurred in the structure of the nucleus on scales smaller than the VLA beam size (i.e., within the central ∼0.''1 (15 pc)), between the two epochs, possibly due to the appearance and fading of new components or shocks in the jet, consistent with previous detection of subparsec-scale nuclear structure in this Seyfert. Our results suggest that all Seyferts may exhibit variation in their nuclear radio flux density at 8.4 GHz, but that variability is more easily recognized in compact sources in which emission from the variable nucleus is not diluted by unresolved, constant flux density radio jet emission

  4. Investigation of copper nuclei

    International Nuclear Information System (INIS)

    Delfini, M.G.

    1983-01-01

    An extensive study has been performed on copper isotopes in the mass region A=63-66. The results of a precise measurement are presented on the properties of levels of 64 Cu and 66 Cu. They were obtained by bombarding the 63 Cu and 65 Cu nuclei with neutrons. The gamma spectra collected after capture of thermal, 2-keV, 24-keV neutrons have been analysed and combined to give a rather extensive set of precise level energies and gamma transition strengths. From the angular distribution of the gamma rays it is possible to obtain information concerning the angular momentum J of several low-lying states. The level schemes derived from such measurements have been used as a test for calculations in the framework of the shell model. The spectral distributions of eigenstates in 64 Cu for different configuration spaces are presented and discussed. In this study the relative importance of configurations with n holes in the 1f7/2 shell with n up to 16, are investigated. It is found that the results strongly depend on the values of the single-particle energies. The results of the spectral-distribution method were utilized for shell-model calculations. From the information obtained from the spectral analysis it was decided to adopt a configuration space which includes up to one hole in the 1f7/2 shell and up to two particles in the 1g9/2 shell. Further, restrictions on seniority and on the coupling of the two particles in the 1g9/2 orbit have been applied and their effects have been studied. It is found that the calculated excitation energies reproduce the measured values in a satisfactory way, but that some of the electromagnetic properties are less well in agreement with experimental data. (Auth.)

  5. Quest for superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Heenen, P.H. [Universite Libre de Bruxelles, Service de Physique Nucleaire Theorique (Belgium); Nazarewicz, W. [Tennessee Univ., Knoxville, TN (United States). Dept. of Physics; Warsaw Univ. (Poland). Inst. Fizyki Teoretycznej

    2002-02-01

    This article draws the long history of the discovery of new heavy nuclei since its beginning in 1940 when neptunium was found, and presents the current status of research in this field. The last 3 years have brought a number of experimental surprises which have truly rejuvenated the field. In January 1999, scientists from Dubna (Russia) reported the synthesis of 1 atom of element 114 ({sup 298}Uuq) in a hot fusion reaction between a {sup 48}Ca beam and a {sup 244}Pu target. This discovery was followed by 3 other reports from Dubna. First using the {sup 242}Pu({sup 48}Ca,3n) reaction, they produced {sup 287}Uuq. In 1999 the synthesis of another isotope of Z=114, the even-even {sup 288}Uuq was reported. The element Z=116 ({sup 292}Uuh) was discovered as a product of the {sup 248}Cm({sup 48}Ca,4n) reaction. The GSI (Germany) group found a new even isotope of the element 110: {sup 270}Uun and also {sup 272}Uuu (element 111) and {sup 277}Uub (element 112). 2 new isotopes of the element 107: {sup 266}Bh and {sup 267}Bh have been found at Berkeley (Usa). The synthesis of the new element Z=118 ({sup 293}Uuo) announced in 1999 by the Berkeley group was retracted 2 years later. The lifetimes reported for the elements {sup 284}Uub and {sup 280}Uun are by many orders of magnitude longer than those of the isotopes with Z{<=}112 previously discovered at GSI. (A.C.)

  6. Contact Lens-Related Eye Infections

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Contact Lens-Related Eye Infections Sections Contact Lens-Related Eye ... Six Steps to Avoid Contact Lens Infections Contact Lens-Related Eye Infections Leer en Español: Infecciones relacionadas ...

  7. 21 CFR 886.1375 - Bagolini lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bagolini lens. 886.1375 Section 886.1375 Food and... OPHTHALMIC DEVICES Diagnostic Devices § 886.1375 Bagolini lens. (a) Identification. A Bagolini lens is a device that consists of a plane lens containing almost imperceptible striations that do not obscure...

  8. Straylight Measurements in Contact Lens Wear

    NARCIS (Netherlands)

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

    2010-01-01

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

  9. Rat silicone hydrogel contact lens model: effects of high- versus low-Dk lens wear.

    Science.gov (United States)

    Zhang, Yunfan; Gabriel, Manal M; Mowrey-McKee, Mary F; Barrett, Ronald P; McClellan, Sharon; Hazlett, Linda D

    2008-11-01

    This study used a rat contact lens (CL) model to test if high- versus low-Dk lens wear caused changes in (1) conjunctival Langerhans cell (LC) number or location; (2) Bcl-2 expression; and (3) infection risk. Female, Lewis rats wore a high- or low-Dk CL continuously for 2 weeks. Afterward, corneas were harvested and processed for ADPase activity to identify LCs, for immunostaining and for real time-polymerase chain reaction. Contact lens-wearing rats also were challenged with Pseudomonas aeruginosa by placing a bacterial-soaked CL on the eye followed by topical delivery of bacteria. After 48 hrs, slit lamp examination and real time-polymerase chain reaction were used to evaluate the corneal response. Conjunctival LC were significantly increased after low- versus high-Dk CL wear (PDk lens wearing group. Bcl-2 mRNA levels were significantly decreased in low- versus high-Dk CL wearing rats, while Bax, FasL, caspase 3, and caspase 9 levels were unchanged. Immunostaining for Bcl-2 showed fewer positively stained epithelial cells in the low- versus high-Dk lens wearing group. After bacterial challenge, 30% of low- versus none of the high-Dk CL wearing corneas became infected and showed increased mRNA levels for several proinflammatory cytokines/chemokines, inducible nitric oxide synthase and matrix metalloproteinase-9. Low- versus high-Dk or non-CL wear led to an increased number of conjunctival LC, decreased Bcl-2 levels, and increased the risk of bacterial infection.

  10. Immunohistochemical studies of lens crystallins in the dysgenetic lens (dyl) mutant mice

    NARCIS (Netherlands)

    Brahma, S.K.; Sanyal, S.

    1984-01-01

    The lens in the dyl mutant mice shows a persistent lens-ectodermal connection as well as degeneration and extrusion of lens materials after the initial differentiation of the fibres. Immunohistochemical investigation of the ontogeny of the lens crystallins in this developing mutant lens has been

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

    Science.gov (United States)

    Sengor, Tomris; Kurna, Sevda Aydin; Aki, Suat; Ozkurt, Yelda

    2011-01-01

    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. 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. 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. 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.

  12. Spectrin-like proteins in plant nuclei

    NARCIS (Netherlands)

    Ruijter, de N.C.A.; Ketelaar, T.; Blumenthal, S.S.D.; Emons, A.M.C.; Schel, J.H.N.

    2000-01-01

    We analysed the presence and localization of spectrin-like proteins in nuclei of various plant tissues, using several anti-erythrocyte spectrin antibodies on isolated pea nuclei and nuclei in cells. Western blots of extracted purified pea nuclei show a cross-reactive pair of bands at 220–240 kDa,

  13. Crystalline lens and refractive development.

    Science.gov (United States)

    Iribarren, Rafael

    2015-07-01

    Individual refractive errors usually change along lifespan. Most children are hyperopic in early life. This hyperopia is usually lost during growth years, leading to emmetropia in adults, but myopia also develops in children during school years or during early adult life. Those subjects who remain emmetropic are prone to have hyperopic shifts in middle life. And even later, at older ages, myopic shifts are developed with nuclear cataract. The eye grows from 15 mm in premature newborns to approximately 24 mm in early adult years, but, in most cases, refractions are maintained stable in a clustered distribution. This growth in axial length would represent a refractive change of more than 40 diopters, which is compensated by changes in corneal and lens powers. The process which maintains the balance between the ocular components of refraction during growth is still under study. As the lens power cannot be measured in vivo, but can only be calculated based on the other ocular components, there have not been many studies of lens power in humans. Yet, recent studies have confirmed that the lens loses power during growth in children, and that hyperopic and myopic shifts in adulthood may be also produced by changes in the lens. These studies in children and adults give a picture of the changing power of the lens along lifespan. Other recent studies about the growth of the lens and the complexity of its internal structure give clues about how these changes in lens power are produced along life. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Single lens laser beam shaper

    Science.gov (United States)

    Liu, Chuyu [Newport News, VA; Zhang, Shukui [Yorktown, VA

    2011-10-04

    A single lens bullet-shaped laser beam shaper capable of redistributing an arbitrary beam profile into any desired output profile comprising a unitary lens comprising: a convex front input surface defining a focal point and a flat output portion at the focal point; and b) a cylindrical core portion having a flat input surface coincident with the flat output portion of the first input portion at the focal point and a convex rear output surface remote from the convex front input surface.

  15. 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...

  16. Cholesterol Bilayer Domains in the Eye Lens Health: A Review.

    Science.gov (United States)

    Widomska, Justyna; Subczynski, Witold K; Mainali, Laxman; Raguz, Marija

    2017-12-01

    The most unique biochemical characteristic of the eye lens fiber cell plasma membrane is its extremely high cholesterol content, the need for which is still unclear. It is evident, however, that the disturbance of Chol homeostasis may result in damages associated with cataracts. Electron paramagnetic resonance methods allow discrimination of two types of lipid domains in model membranes overloaded with Chol, namely, phospholipid-cholesterol domains and pure Chol bilayer domains. These domains are also detected in human lens lipid membranes prepared from the total lipids extracted from lens cortices and nuclei of donors from different age groups. Independent of the age-related changes in phospholipid composition, the physical properties of phospholipid-Chol domains remain the same for all age groups and are practically identical for cortical and nuclear membranes. The presence of Chol bilayer domains in these membranes provides a buffering capacity for cholesterol concentration in the surrounding phospholipid-Chol domains, keeping it at a constant saturating level and thus keeping the physical properties of the membrane consistent with and independent of changes in phospholipid composition. It seems that the presence of Chol bilayer domains plays an integral role in the regulation of cholesterol-dependent processes in fiber cell plasm membranes and in the maintenance of fiber cell membrane homeostasis.

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

    Directory of Open Access Journals (Sweden)

    Deeksha V Thakur

    2014-01-01

    Full Text Available Background & objectives: With increasing use of soft contact lenses the incidence of contact lens induced infections is also increasing. This study was aimed to assess the knowledge of new and existing contact lens users about the risk of microbial contamination associated with improper use and maintenance of contact lenses, type of microbial flora involved and their potential to cause ophthalmic infections. Methods: Four samples each from 50 participants (n=200 were collected from the lenses, lens care solutions, lens care solution bottles and lens cases along with a questionnaire regarding their lens use. The samples were inoculated onto sheep blood agar, Mac Conkey′s agar and Sabouraud′s dextrose agar. Organisms were identified using standard laboratory protocols. Results: Overall rate of microbial contamination among the total samples was 52 per cent. The most and the least contaminated samples were found to be lens cases (62% and lens care solution (42%, respectively. The most frequently isolated contaminant was Staphylococcus aureus (21% followed by Pseudomonas species (19.5%. Majority (64% of the participants showed medium grade of compliance to lens cleaning practices. Rate of contamination was 100 and 93.75 per cent respectively in those participants who showed low and medium compliance to lens care practices as compared to those who had high level of compliance (43.75% ( p0 <0.05. Interpretation & conclusions: Lens care practices amongst the participants were not optimum which resulted into high level contamination. Hence, creating awareness among the users about the lens care practices and regular cleaning and replacements of lens cases are required.

  18. From heavy nuclei to super-heavy nuclei

    International Nuclear Information System (INIS)

    Theisen, Ch.

    2003-01-01

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

  19. Complete destruction of heavy nuclei by hadrons and nuclei

    International Nuclear Information System (INIS)

    Tolstov, K.D.

    1980-01-01

    The total disintegration is considered of Ag and Pb nuclei and 4 He, 12 C nuclei With a momentum of 4.5 GeV/c per nucleon. It is shown that nucleons are mainly emitted, and there is no residual nUcleus the mass of which is comparable to that of the primary nucleus. The probability of total nucleus disintegration is considered as a function of projectile energy and the mass. The multiplicity, energy and emission angle of particles are considerred as well. It is shown that the density of nuclear matter in the overlap zone of colliding nuclei exceeds the usual one by a factor of approximately 4. A comparison is made with interaction models. A conclusion is drawn of the collective interaction mechanism (perhaps, of the shock wave type) of particle ejection from the target nucleus at the first stage of interaction and of explosive decay of the residual nucleus at the next one

  20. ASSESSMENT OF LENS THICKNESS IN ANGLE CLOSURE DISEASE

    Directory of Open Access Journals (Sweden)

    Nishat Sultana Khayoom

    2016-08-01

    Full Text Available BACKGROUND Anterior chamber depth and lens thickness have been considered as important biometric determinants in primary angle-closure glaucoma. Patients with primary narrow angle may be classified as a primary angle closure suspect (PACS, or as having primary angle closure (PAC or primary angle closure glaucoma (PACG. 23.9% of patients with primary angle closure disease are in India, which highlights the importance of understanding the disease, its natural history, and its underlying pathophysiology, so that we may try to establish effective methods of treatment and preventative measures to delay, or even arrest, disease progression, thereby reducing visual morbidity. AIM To determine the lens thickness using A-scan biometry and its significance in various stages of angle closure disease. MATERIALS AND METHODS Patients attending outpatient department at Minto Ophthalmic Hospital between October 2013 to May 2015 were screened for angle closure disease and subsequently evaluated at glaucoma department. In our study, lens thickness showed a direct correlation with shallowing of the anterior chamber by determining the LT/ ACD ratio. A decrease in anterior chamber depth is proportional to the narrowing of the angle which contributes to the progression of the angle closure disease from just apposition to occlusion enhancing the risk for optic nerve damage and visual field loss. Hence, if the lens thickness values are assessed earlier in the disease process, appropriate intervention can be planned. CONCLUSION Determination of lens changes along with anterior chamber depth and axial length morphometrically can aid in early detection of angle closure. The role of lens extraction for PACG is a subject of increased interest. Lens extraction promotes the benefits of anatomical opening of the angle, IOP reduction and improved vision. This potential intervention may be one among the armamentarium of approaches for PACG. Among the current treatment modalities

  1. Improved illumination system of laparoscopes using an aspherical lens array.

    Science.gov (United States)

    Wu, Rengmao; Qin, Yi; Hua, Hong

    2016-06-01

    The current fiber-based illumination systems of laparoscopes are unable to uniformly illuminate a large enough area in abdomen due to the limited numerical aperture (NA) of the fiber bundle. Most energy is concentrated in a small region at the center of the illumination area. This limitation becomes problematic in laparoscopes which require capturing a wide field of view. In this paper, we propose an aspherical lens array which is used to direct the outgoing rays from the fiber bundle of laparoscope to produce a more uniformly illuminated, substantially larger field coverage than standalone fiber source. An intensity feedback method is developed to design the aspherical lens unit for extended non-Lambertian sources, which is the key to the design of this lens array. By this method, the lens unit is obtained after only one iteration, and the lens array is constructed by Boolean operation. Then, the ray-tracing technique is used to verify the design. Further, the lens array is fabricated and experimental tests are performed. The results clearly show that the well-illuminated area is increased to about 0.107m(2) from 0.02m(2) (about 5x larger than a standard fiber illumination source). More details of the internal organs can be clearly observed under this improved illumination condition, which also reflects the significant improvement in the optical performance of the laparoscope.

  2. Reflection asymmetric shapes in nuclei

    International Nuclear Information System (INIS)

    Ahmad, I.; Carpenter, M.P.; Emling, H.

    1989-01-01

    Experimental data show that there is no even-even nucleus with a reflection asymmetric shape in its ground state. Maximum octupole- octupole correlations occur in nuclei in the mass 224 (N∼134, Z∼88) region. Parity doublets, which are the characteristic signature of octupole deformation, have been observed in several odd mass Ra, Ac and Pa nuclei. Intertwined negative and positive parity levels have been observed in several even-even Ra and Th nuclei above spin ∼8ℎ. In both cases, the opposite parity states are connected by fast El transitions. In some medium-mass nuclei intertwined negative and positive parity levels have also been observed above spin ∼7ℎ. The nuclei which exhibit octupole deformation in this mass region are 144 Ba, 146 Ba and 146 Ce; 142 Ba, 148 Ce, 150 Ce and 142 Xe do not show these characteristics. No case of parity doublet has been observed in the mass 144 region. 32 refs., 16 figs., 1 tab

  3. Human lens colouration, age and cataract

    International Nuclear Information System (INIS)

    Truscott, R.J.W.; Garner, B.; Hood, B.

    1999-01-01

    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

  4. Calculation of crystalline lens power in chickens with a customized version of Bennett's equation.

    Science.gov (United States)

    Iribarren, Rafael; Rozema, Jos J; Schaeffel, Frank; Morgan, Ian G

    2014-03-01

    This paper customizes Bennett's equation for calculating lens power in chicken eyes from refraction, keratometry and biometry. Previously published data on refraction, corneal power, anterior chamber depth, lens thickness, lens radii of curvature, axial length and eye power in chickens aged 10-90 days were used to estimate Gullstrand's lens power and Bennett's lens power for chicken eyes, and to calculate the lens equivalent refractive index. Bennett's A and B constants for the front and back surface powers of the lens were calculated for data measured from day 10 to 90 at 10 day intervals, and mean customized constants were calculated. The mean customized constants for Bennett's equation for chicks were A=0.574±0.023 and B=0.379±0.021. As found previously, lens power decreases with age in chicks, while corneal power decreases and axial length increases. The lens equivalent refractive index decreases with age from 10 to 90 days after hatching. Bennett's equation can be used to calculate lens power in chicken eyes for studies on animal myopia, using standard biometry. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Interaction of slow pions with atomic nuclei

    International Nuclear Information System (INIS)

    Troitskij, M.A.; Tsybul'nikov, A.V.; Chekunaev, N.I.

    1984-01-01

    Interactions of slow pions with atomic nuclei near to pion condensation are investigated. From comparison of experimental data with the theoretical calculation results on the basis of precise microscopic approach not bound with the random phase approximation (RPA) nuclear matter fundamental parameters near a critical point can be found. Optical potential of slow pions in nuclei, πN-scattering amplitudes and lengths, π-atom level isotopic shift, phenomenon of single-nucleon pion absorption by nucleus, phenomenon of nuclear critical opalescence are considered. The results of πN-scattering lengths calculation, sup(40-44)Ca, sup(24-29)Mg, sup(16-18)O π-atom level shift are presented. It is shown that the presence of π-condensate in nuclei can explain the observed suppression of p-wave potential terms. The phenomenon of single-nucleon pion absorption by nucleus is one of direct experiments which permits to reveal the π-condensate. The nuclear opalescence phenomenon is manifested in increase of pion photoproduction reaction cross section for account of nucleus proximity to π-condensation as compared with the calculated in the Fermi-gas model. The suggested method for calculating precondensate phenomena operates the better, the nearer is the system to the condensation threshold whereas the RPA method in this region is inapplicable

  6. Conservation through the economics lens.

    Science.gov (United States)

    Farley, Joshua

    2010-01-01

    Although conservation is an inherently transdisciplinary issue, there is much to be gained from examining the problem through an economics lens. Three benefits of such an approach are laid out in this paper. First, many of the drivers of environmental degradation are economic in origin, and the better we understand them, the better we can conserve ecosystems by reducing degradation. Second, economics offers us a when-to-stop rule, which is equivalent to a when-to-conserve rule. All economic production is based on the transformation of raw materials provided by nature. As the economic system grows in physical size, it necessarily displaces and degrades ecosystems. The marginal benefits of economic growth are diminishing, and the marginal costs of ecological degradation are increasing. Conceptually, we should stop economic growth and focus on conservation when the two are equal. Third, economics can help us understand how to efficiently and justly allocate resources toward conservation, and this paper lays out some basic principles for doing so. Unfortunately, the field of economics is dominated by neoclassical economics, which builds an analytical framework based on questionable assumptions and takes an excessively disciplinary and formalistic approach. Conservation is a complex problem, and analysis from individual disciplinary lenses can make important contributions to conservation only when the resulting insights are synthesized into a coherent vision of the whole. Fortunately, there are a number of emerging transdisciplines, such as ecological economics and environmental management, that are dedicated to this task.

  7. A Class I UV-Blocking (senofilcon A) Soft Contact Lens Prevents UVA-induced Yellow Fluorescence and NADH loss in the Rabbit Lens Nucleus in vivo

    Science.gov (United States)

    Giblin, Frank J.; Lin, Li-Ren; Simpanya, Mukoma F.; Leverenz, Victor R.; Fick, Catherine E.

    2012-01-01

    It is known that fluorescence, much of it caused by UVA light excitation, increases in the aging human lens, resulting in loss of sharp vision. This study used an in vivo animal model to investigate UVA-excited fluorescence in the rabbit lens, which contains a high level of the UVA chromophore NADH, existing both free and bound to λ-crystallin. Also, the ability of a Class I (senofilcon A) soft contact lens to protect against UVA-induced effects on the rabbit lens was tested. Rabbit eyes were irradiated with UVA light in vivo (100 mW/cm2 on the cornea) for 1 hour using monochromatic 365 nm light. Irradiation was conducted in the presence of either a senofilcon A contact lens, a minimally UV-absorbing lotrafilcon A contact lens, or no contact lens at all. Eyes irradiated without a contact lens showed blue 365 nm-excited fluorescence initially, but this changed to intense yellow fluorescence after 1 hour. Isolated, previously irradiated lenses exhibited yellow fluorescence originating from the lens nucleus when viewed under 365 nm light, but showed normal blue fluorescence arising from the cortex. Previously irradiated lenses also exhibited a faint yellow color when observed under visible light. The senofilcon A contact lens protected completely against the UVA-induced effects on fluorescence and lens yellowing, whereas the lotrafilcon A lens showed no protection. The UVA-exposure also produced a 53% loss of total NADH (free plus bound) in the lens nucleus, with only a 13% drop in the anterior cortex. NADH loss in the nucleus was completely prevented with use of a senofilcon A contact lens, but no significant protection was observed with a lotrafilcon A lens. Overall, the senofilcon A lens provided an average of 67% protection against UVA-induced loss of four pyridine nucleotides in four different regions of the lens. HPLC analysis with fluorescence detection indicated a nearly six-fold increase in 365 nm-excited yellow fluorescence arising from lens nuclear

  8. Which soft lens power is better for piggyback in keratoconus? Part II.

    Science.gov (United States)

    Romero-Jiménez, Miguel; Santodomingo-Rubido, Jacinto; González-Meijóme, Jose-Manuel; Flores-Rodriguez, Patricia; Villa-Collar, Cesar

    2015-02-01

    To evaluate how soft lens power affects rigid gas-permeable (RGP) lens power and visual acuity (VA) in piggyback fittings for keratoconus. Sixteen keratoconus subjects (30 eyes) were included in the study. Piggyback contact lens fittings combining Senofilcon-A soft lenses of -6.00, -3.00, +3.00 and +6.00 D with Rose K2 RGP contact lenses were performed. Corneal topography was taken on the naked eye and over each soft contact lens before fitting RGP lenses. Mean central keratometry, over-refraction, RGP back optic zone radius (BOZR) and estimated final power as well as VA were recorded and analyzed. In comparison to the naked eye, the mean central keratometry flattened with both negative lens powers (psoft lens power (p=1.0); and steepened with the +6.00 soft lens power (p=0.02). Rigid gas-permeable over-refraction did not change significantly between different soft lens powers (all p>0.05). RGP's BOZR decreased significantly with both positive in comparison with both negative soft lens powers (all ppowers separately (both p>0.05). Estimated RGP's final power increased significantly with positive in comparison with negative lens powers (all ppowers separately (both p>0.05). Visual acuity did not change significantly between the different soft lens powers assessed (all p>0.05). The use of negative-powered soft lenses in piggyback fitting reduces RGP lens power without impacting VA in keratoconus subjects. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  9. Protonic decay of oriented nuclei

    International Nuclear Information System (INIS)

    Kadmensky, S.G.

    2002-01-01

    On the basis of the multiparticle theory of protonic decay, the angular distributions of protons emitted by oriented spherical and deformed nuclei in the laboratory frame and in the internal coordinate frame of deformed parent nuclei are constructed with allowance for symmetry with respect to time inversion. It is shown that, because of the deep-subbarrier character of protonic decay, the adiabatic approximation is not applicable to describing the angular distributions of protons emitted by oriented deformed nuclei and that the angular distribution of protons in the laboratory frame does not coincide with that in the internal coordinate frame. It is demonstrated that these angular distributions coincide only if the adiabatic and the semiclassical approximation are simultaneously valid

  10. Nuclei in a neutron star

    International Nuclear Information System (INIS)

    Oyamatsu, K.; Yamada, M.

    1994-01-01

    We report on the recent progress in understanding the matter in the crust of a neutron star. For nuclides in the outer crust, recently measured masses of neutron-rich nuclei enable us to determine more accurately the stable nuclide as a function of the matter density. In the inner crust, the compressible liquid-drop model predicts successive change of the nuclear shape, from sphere to cylinder, slab, cylindrical hole and spherical hole at densities just before the transition to uniform matter. In order to go beyond the liquiddrop model, we performed the Thomas-Fermi calculation paying special attention to the surface diffuseness, and have recently calculated the shell energies of the non-spherical nuclei. We have found from these studies that all these non-spherical nuclei exist stably in the above order even if we include the surface diffuseness and shell energies. (author)

  11. Giant dipole resonance in hot nuclei

    International Nuclear Information System (INIS)

    Mau, N.V.

    1993-01-01

    Giant resonances built on an excited state of the nucleus at a finite temperature T are studied. The following questions are investigated: how long such collective effects occur in a nucleus when T increases. How the properties of the giant resonances vary when the temperature increases. How the study of giant resonances in hot nuclei can give information on the structure of the nucleus in a highly excited state. The special case of the giant dipole resonance is studied. Some of the experimental results are reviewed and in their theoretical interpretation is discussed. (K.A.). 56 refs., 20 figs., 4 tabs

  12. Finite element modelling of radial lentotomy cuts to improve the accommodation performance of the human lens.

    Science.gov (United States)

    Burd, H J; Wilde, G S

    2016-04-01

    The use of a femtosecond laser to form planes of cavitation bubbles within the ocular lens has been proposed as a potential treatment for presbyopia. The intended purpose of these planes of cavitation bubbles (referred to in this paper as 'cutting planes') is to increase the compliance of the lens, with a consequential increase in the amplitude of accommodation. The current paper describes a computational modelling study, based on three-dimensional finite element analysis, to investigate the relationship between the geometric arrangement of the cutting planes and the resulting improvement in lens accommodation performance. The study is limited to radial cutting planes. The effectiveness of a variety of cutting plane geometries was investigated by means of modelling studies conducted on a 45-year human lens. The results obtained from the analyses depend on the particular modelling procedures that are employed. When the lens substance is modelled as an incompressible material, radial cutting planes are found to be ineffective. However, when a poroelastic model is employed for the lens substance, radial cuts are shown to cause an increase in the computed accommodation performance of the lens. In this case, radial cuts made in the peripheral regions of the lens have a relatively small influence on the accommodation performance of the lens; the lentotomy process is seen to be more effective when cuts are made near to the polar axis. When the lens substance is modelled as a poroelastic material, the computational results suggest that useful improvements in lens accommodation performance can be achieved, provided that the radial cuts are extended to the polar axis. Radial cuts are ineffective when the lens substance is modelled as an incompressible material. Significant challenges remain in developing a safe and effective surgical procedure based on this lentotomy technique.

  13. Neutron scattering on deformed nuclei

    International Nuclear Information System (INIS)

    Hansen, L.F.; Haight, R.C.; Pohl, B.A.; Wong, C.; Lagrange, C.

    1984-09-01

    Measurements of neutron elastic and inelastic differential cross sections around 14 MeV for 9 Be, C, 181 Ta, 232 Th, 238 U and 239 Pu have been analyzed using a coupled channel (CC) formalism for deformed nuclei and phenomenological global optical model potentials (OMP). For the actinide targets these results are compared with the predictions of a semi-microscopic calculation using Jeukenne, Lejeune and Mahaux (JLM) microscopic OMP and a deformed ground state nuclear density. The overall agreement between calculations and the measurements is reasonable good even for the very light nuclei, where the quality of the fits is better than those obtained with spherical OMP

  14. Nuclei, hadrons, and elementary particles

    International Nuclear Information System (INIS)

    Bopp, F.W.

    1989-01-01

    This book is a short introduction to the physics of the nuclei, hadrons, and elementary particles for students of physics. Important facts and model imaginations on the structure, the decay, and the scattering of nuclei, the 'zoology' of the hadrons and basic facts of hadronic scattering processes, a short introduction to quantum electrodynamics and quantum chromodynamics and the most important processes of lepton and parton physics, as well as the current-current approach of weak interactions and the Glashow-Weinberg-Salam theory are presented. (orig.) With 153 figs., 10 tabs [de

  15. Octupole shapes in heavy nuclei

    International Nuclear Information System (INIS)

    Ahmad, I.

    1994-01-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets

  16. Exotic Nuclei Arena in JHP

    International Nuclear Information System (INIS)

    Nomura, T.

    1991-12-01

    The Exotic Nuclei Arena planned in Japanese Hadron Project aims to accelerate various unstable nuclei produced in 1-GeV proton-induced reactions up to 6.5 MeV/u by means of heavy-ion linacs. The present status of research and development for the Earena is briefly reported. The construction of the prototype facility to accelerate unstable beams up to 0.8 MeV/u is planned in 1992-94, in which the existing cyclotron in INS is used as the primary accelerator. (author)

  17. Spinodal decomposition of atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, P. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Colonna, M.; Guarnera, A. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)]|[LNS, Catania (Italy)

    1996-12-31

    Multifragmentation of atomic nuclei is discussed. It is shown that this description of the dynamics of first order phase transitions in infinite and finite system is now partially achieved. An important conclusion is that in some specific cases well-defined collective motions were initiating the self-organisation of the unstable matter in fragments. In the case of finite systems the possible signals kept from this early fragmentation stage can inform on the possible occurrence of a liquid-gas phase transition in nuclei. (K.A.). 21 refs.

  18. Spinodal decomposition of atomic nuclei

    International Nuclear Information System (INIS)

    Chomaz, P.; Colonna, M.; Guarnera, A.

    1996-01-01

    Multifragmentation of atomic nuclei is discussed. It is shown that this description of the dynamics of first order phase transitions in infinite and finite system is now partially achieved. An important conclusion is that in some specific cases well-defined collective motions were initiating the self-organisation of the unstable matter in fragments. In the case of finite systems the possible signals kept from this early fragmentation stage can inform on the possible occurrence of a liquid-gas phase transition in nuclei. (K.A.)

  19. Are there superheavy atomic nuclei

    International Nuclear Information System (INIS)

    Herrmann, G.

    1982-04-01

    The author presents a populary introduction to the formation of nuclei with special regards to superheavy nuclei. After a general description of the methods of physics the atomic hypothesis is considered. Thereafter the structure of the nucleus is discussed, and the different isotopes are considered. Then radioactivity is described as an element transmutation. Thereafter the thermonuclear reactions in the sun are considered. Then the synthesis of elements using heavy ion reactions is described. In this connection the transuranium elements and the superheavy elements are considered. (orig./HSI) [de

  20. The morphology of cometary nuclei

    Science.gov (United States)

    Keller, H. U.; Jorda, L.

    condensations of comets were agglomerations of dust particles prevailed for about a century. The gas coma was explained by desorption of molecules from dust particles with large surfaces (Levin 1943). The storage of highly reactive radicals (most observed species (CN, CH, NH2, etc.) were of this category) posed a major difficulty to be explained. The inference that these radicals should be dissociation products of stable parent molecules (such as (CN)2, CH4, NH3, etc.) by Wurm (1934, 1935, 1943) led to our present understanding that these molecules are stored as ices within the central nucleus of a comet. Whipple (1950a,b) combined the astrometrical observations of changes of the orbital periods of comets with the existence of an icy cometary nucleus. The sublimation of ices cause reactive (rocket) non-gravitational forces that increase or decrease the orbital period of an active comet according to the sense of rotation of its nucleus. Evidence in support of the icy conglomerate nucleus became more and more compelling by the derived high gas production rates that could not be stored by adsorption on dust grains (Biermann and Trefftz 1964, Huebner 1965, Keller 1976a,b) and by the same account by the large quantities of dust moving into the cometary tail (Finson and Probstein 1968b). The `sand bank' model (Lyttleton 1953) was clearly dismissed in favour of a solid icy nucleus. Its formation and origin could now be explored. While there was some knowledge about the chemical composition of the nucleus, its physical properties, even the basic ones like size, shape and mass, remained largely unknown because the nucleus could not be observed. Early attempts to derive the nucleus size from the `nuclear' magnitudes of comets at large heliocentric distances while they are inactive (Roemer 1966a,b) led to a systematic overestimation of the size because their residual activity could not be eliminated. The advent of modern detectors and large ground-based telescopes revealed that most

  1. Manufacturing PDMS micro lens array using spin coating under a multiphase system

    International Nuclear Information System (INIS)

    Sun, Rongrong; Yang, Hanry; Rock, D Mitchell; Danaei, Roozbeh; Panat, Rahul; Kessler, Michael R; Li, Lei

    2017-01-01

    The development of micro lens arrays has garnered much interest due to increased demand of miniaturized systems. Traditional methods for manufacturing micro lens arrays have several shortcomings. For example, they require expensive facilities and long lead time, and traditional lens materials (i.e. glass) are typically heavy, costly and difficult to manufacture. In this paper, we explore a method for manufacturing a polydimethylsiloxane (PDMS) micro lens array using a simple spin coating technique. The micro lens array, formed under an interfacial tension dominated system, and the influence of material properties and process parameters on the fabricated lens shape are examined. The lenses fabricated using this method show comparable optical properties—including surface finish and image quality—with a reduced cost and manufacturing lead time. (paper)

  2. The mechanism of total disintegration of heavy nuclei by fast hadrons and nuclei

    International Nuclear Information System (INIS)

    Strugalska-Gola, E.; Strugalski, Z.

    1997-01-01

    The mechanism of the total disintegration of atomic nuclei by fast hadrons and nuclei is considered. The passage of energetic hadrons through layers of intranuclear matter, accompanied by emission of fast nucleons with kinetic energies from about 20 up to about 500 MeV from definite local small regions in the nuclei around projectile courses in them, allows one to explain simply the occurrence of the total destruction of nuclei involved in the collisions. Light nuclei may be totally disintegrated by fast hadrons and nuclei; heavier nuclei may be totally disintegrated only in central collisions of nuclei with similar mass numbers

  3. Spectroscopy of very heavy nuclei with a view to study super-heavy nuclei

    International Nuclear Information System (INIS)

    Khalfallah, F.

    2007-08-01

    Within the recent years, the spectroscopic study of single particle orbitals of very heavy elements (VHE) has become possible with the development of increasingly efficient experimental setups. This allows us, through nuclear deformation, to access with these deformed nuclei to orbitals situated around the Fermi level in the spherical superheavy elements (SHE) and learn more about the nuclear structure of these nuclei. The aim of this work is the spectroscopic studies of heavy and very heavy elements. Because of the experimental difficulties associated with the fusion reactions in the VHE region, a detailed optimization studies is essential. Simulation of energy loss and angular straggling of these nuclei due to the interaction in the target and to neutron's evaporation was carried out and allowed us to optimize the angular acceptance of the separators according to the target thickness. An extensive survey and exploration in the VHE region was also conducted on the basis of cross section's systematics in the literature and simulations carried out using the statistical code Hivap. In this framework, the possible extension of the range of validity of a set of Hivap parameters was investigated. This work has enabled us to prepare a list of experiments of interest for the production of very heavy nuclei. In this thesis, our work was concentrated on the spectroscopy of the nuclei No 256 et Rf 256 for which two experimental proposals were accepted. The octupole deformations predicted in the actinides region is studied in another part of this thesis, a part witch is dedicated to the gamma spectroscopy of Pa 223 . The data from a new experiment carried out using the Jurogam-Ritu-Great setup are analysed and compared to previous results. They confirm the octupole deformed shape in this nucleus. (author)

  4. Improved integrating-sphere throughput with a lens and nonimaging concentrator.

    Science.gov (United States)

    Chenault, D B; Snail, K A; Hanssen, L M

    1995-12-01

    A reflectometer design utilizing an integrating sphere with a lens and nonimaging concentrator is described. Compared with previous designs where a collimator was used to restrict the detector field of view, the concentrator-lens combination significantly increases the throughput of the reflectometer. A procedure for designing lens-concentrators is given along with the results of parametric studies. The measured angular response of a lens-concentrator system is compared with ray-trace predictions and with the response of an ideal system.

  5. Fresnel Lens Solar Concentrator Design Based on Geometric Optics and Blackbody Radiation Equations

    Science.gov (United States)

    Watson, Michael D.; Jayroe, Robert, Jr.

    1999-01-01

    Fresnel lenses have been used for years as solar concentrators in a variety of applications. Several variables effect the final design of these lenses including: lens diameter, image spot distance from the lens, and bandwidth focused in the image spot. Defining the image spot as the geometrical optics circle of least confusion and applying blackbody radiation equations the spot energy distribution can be determined. These equations are used to design a fresnel lens to produce maximum flux for a given spot size, lens diameter, and image distance. This approach results in significant increases in solar efficiency over traditional single wavelength designs.

  6. Tinting of intraocular lens implants

    Energy Technology Data Exchange (ETDEWEB)

    Zigman, S.

    1982-06-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users.

  7. Tinting of intraocular lens implants

    International Nuclear Information System (INIS)

    Zigman, S.

    1982-01-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users

  8. Automated Fresnel lens tester system

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.S.

    1981-07-01

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

  9. Early changes in retinal structure and BMP2 expression in the retina and crystalline lens of streptozotocin-induced diabetic pigs.

    Science.gov (United States)

    Jeong, Jae Seung; Lee, Woon-Kyu; Moon, Yeon Sung; Kim, Na Rae

    2017-09-01

    This study aims to evaluate early changes in retinal structure and BMP2 expression in the retina and crystalline lens by comparing streptozotocin-induced diabetic pigs and normal control group pigs. Five eye samples from five diabetic Micro-pigs (Medikinetics, Pyeongtaek, Korea) and five eye samples from five control pigs bred in a specific pathogen-free area were used. Diabetes was developed through intravenous injection of nicotinamide and streptozotocin, and the average fasting glucose level was maintained at 250 mg/dL or higher for 16 weeks. To evaluate BMP2 expression in the retina and crystalline lens, Western blotting was performed. In Hematoxylin and Eosin staining, most diabetic pigs showed structural abnormalities in the inner plexiform layer. The number of nuclei in the ganglion cell layer within the range of 10 4 µm 2 was 3.78±0.60 for diabetic pigs and 5.57±1.07 for control group pigs, showing a statistically significant difference. In immunohistochemical staining, diabetic retinas showed an overall increase in BMP2 expression. In Western blotting, the average BMP2/actin level of diabetic retinas was 1.19±0.05, showing a significant increase compared to the 1.06±0.03 of the control group retinas ( P =0.016). The BMP2/actin level of diabetic crystalline lenses was similar to the control group crystalline lenses ( P =0.730). Compared to control group pigs, the number of nuclei in the inner nuclear layer of retinas from streptozotocin-induced diabetic pigs decreased, while an increase in BMP2 expression was observed in the retina of diabetic pigs.

  10. Transitional nuclei near shell closures

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, G. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Pai, H. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064, India and Present Address: Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)

    2014-08-14

    High spin states in Bismuth and Thallium nuclei near the Z = 82 shell closure and Cesium nuclei near the N = 82 shell closure in A = 190 and A = 130 regions, respectively, have been experimentally investigated using heavy-ion fusion evaporation reaction and by detecting the gamma rays using the Indian National Gamma Array (INGA). Interesting shape properties in these transitional nuclei have been observed. The results were compared with the neighboring nuclei in these two regions. The total Routhian surface (TRS) calculations have been performed for a better understanding of the observed properties. In mass region A = 190, a change in shape from spherical to deformed has been observd around neutron number N = 112 for the Bi (Z = 83) isotopes with proton number above the magic gap Z = 82, whereas, the shape of Tl (Z = 81) isotopes with proton number below the magic gap Z = 82 remains stable as a function of neutron number. An important transition from aplanar to planar configuration of angular momentum vectors leading to the occurance of nuclar chirality and magnetic rotation, respectively, has been proposed for the unique parity πh{sub 11/2}⊗νh{sub 11/2} configuration in Cs isotopes in the mass region A ∼ 130 around neutron number N = 79. These results are in commensurate with the TRS calculations.

  11. Cluster structure in Cf nuclei

    International Nuclear Information System (INIS)

    Singh, Shailesh K.; Biswal, S.K.; Bhuyan, M.; Patra, S.K.; Gupta, R.K.

    2014-01-01

    Due to the availability of advance experimental facilities, it is possible to probe the nuclei upto their nucleon level very precisely and analyzed the internal structure which will help us to resolve some mysterious problem of the decay of nuclei. Recently, the relativistic nuclear collision, confirmed the α cluster type structure in the 12 C which is the mile stone for the cluster structure in nuclei. The clustering phenomena in light and intermediate elements in nuclear chart is very interesting. There is a lot of work done by our group in the clustering behaviour of the nuclei. In this paper, the various prospectus of clustering in the isotopes of Cf nucleus including fission state is discussed. Here, 242 Cf isotope for the analysis, which is experimentally known is taken. The relativistic mean field model with well established NL3 parameter set is taken. For getting the exact ground state configuration of the isotopes, the calculation for minimizing the potential energy surface is performed by constraint method. The clustering structure of other Cf isotopes is discussed

  12. Nuclear astrophysics of light nuclei

    DEFF Research Database (Denmark)

    Fynbo, Hans Otto Uldall

    2013-01-01

    A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...

  13. Particle detection from oriented nuclei

    International Nuclear Information System (INIS)

    Wouters, J.; Moor, P. de; Schuurmans, P.; Severijns, N.; Vanderpoorten, W.; Vanneste, L.

    1992-01-01

    A survey is given of particle emission from nuclei that have been spin oriented by cryogenical means. Experiments and recent developments with detectors in the low temperature environment and their on-line application are reviewed. The most recent results are mentioned. Some phenomena to be unraveled in future studies are pointed out. (orig.)

  14. Rotational damping motion in nuclei

    International Nuclear Information System (INIS)

    Egido, J.L.; Faessler, A.

    1991-01-01

    The recently proposed model to explain the mechanism of the rotational motion damping in nuclei is exactly solved. When compared with the earlier approximative solution, we find significative differences in the low excitation energy limit (i.e. Γ μ 0 ). For the strength functions we find distributions going from the Wigner semicircle through gaussians to Breit-Wigner shapes. (orig.)

  15. Percolation and multifragmentation of nuclei

    International Nuclear Information System (INIS)

    Shmakov, S.Yu.; Uzhinskij, V.V.

    1989-01-01

    A method to build the 'cold' nuclei as percolation clusters is suggested. Within the framework of definite assumptions of the character of nucleon-nucleon couplings breaking resulting from the nuclear reactions as description of the multifragmentation process in the hadron-nucleus and nucleus-nucleus reactions at high energies is obtained. 19 refs.; 6 figs

  16. Octupole correlation effects in nuclei

    International Nuclear Information System (INIS)

    Chasman, R.R.

    1992-01-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions

  17. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world's first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density ...

  18. Lens system for SIMS analysis

    International Nuclear Information System (INIS)

    Martinez, G.; Sancho, M.; Garcia-Galan, J.C.

    1987-01-01

    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. Inclusive charge longitudinal response in finite nuclei

    International Nuclear Information System (INIS)

    Alberico, W.M.; Molinari, A.; Czerski, P.; Czerski, P.; Ericson, M.

    1986-03-01

    The experimental dynamic and static longitudinal structure factors of 12 C, 40 Ca and 56 Fe are investigated with a semiclassical RPA theory. The parameters entering into the nuclear mean field (including the nucleon effective mass) and in the isoscalar and isovector particle-hole forces are set by best fitting procedures. Quite reasonable values of these quantities allow a satisfactory account of the experimental data over a wide range of momentum transfers in all the three nuclei. However, to achieve this result, the proton root mean square radius has to be increased over the conventional value of about 13% in 12 C and 22% in 40 Ca and 56 Fe

  20. 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.

  1. Radiation dose to physicians’ eye lens during interventional radiology

    International Nuclear Information System (INIS)

    Bahruddin, N A; Hashim, S; Karim, M K A; Ang, W C; Salehhon, N; Sabarudin, A; Bakar, K A

    2016-01-01

    The demand of interventional radiology has increased, leading to significant risk of radiation where eye lens dose assessment becomes a major concern. In this study, we investigate physicians' eye lens doses during interventional procedures. Measurement were made using TLD-100 (LiF: Mg, Ti) dosimeters and was recorded in equivalent dose at a depth of 0.07 mm, Hp(0.07). Annual Hp(0.07) and annual effective dose were estimated using workload estimation for a year and Von Boetticher algorithm. Our results showed the mean Hp(0.07) dose of 0.33 mSv and 0.20 mSv for left and right eye lens respectively. The highest estimated annual eye lens dose was 29.33 mSv per year, recorded on left eye lens during fistulogram procedure. Five physicians had exceeded 20 mSv dose limit as recommended by international commission of radiological protection (ICRP). It is suggested that frequent training and education on occupational radiation exposure are necessary to increase knowledge and awareness of the physicians’ thus reducing dose during the interventional procedure. (paper)

  2. Refractive lens exchange with a multifocal diffractive aspheric intraocular lens

    Directory of Open Access Journals (Sweden)

    Teresa Ferrer-Blasco

    2012-06-01

    Full Text Available PURPOSE: To evaluate the safety, efficacy and predictability after refractive lens exchange with multifocal diffractive aspheric intraocular lens implantation. METHODS: Sixty eyes of 30 patients underwent bilateral implantation with AcrySof® ReSTOR® SN6AD3 intraocular lens with +4.00 D near addition. Patients were divided into myopic and hyperopic groups. Monocular best corrected visual acuity at distance and near and monocular uncorrected visual acuity at distance and near were measured before and 6 months postoperatively. RESULTS: After surgery, uncorrected visual acuity was 0.08 ± 0.15 and 0.11 ± 0.14 logMAR for the myopic and hyperopic groups, respectively (50% and 46.67% of patients had an uncorrected visual acuity of 20/20 or better in the myopic and hyperopic groups, respectively. The safety and efficacy indexes were 1.05 and 0.88 for the myopic and 1.01 and 0.86 for the hyperopic groups at distance vision. Within the myopic group, 20 eyes remained unchanged after the surgery, and 3 gained >2 lines of best corrected visual acuity. For the hyperopic group, 2 eyes lost 2 lines of best corrected visual acuity, 21 did not change, and 3 eyes gained 2 lines. At near vision, the safety and efficacy indexes were 1.23 and 1.17 for the myopic and 1.16 and 1.13 for the hyperopic groups. Best corrected near visual acuity improved after surgery in both groups (from 0.10 logMAR to 0.01 logMAR in the myopic group, and from 0.10 logMAR to 0.04 logMAR in the hyperopic group. CONCLUSIONS: The ReSTOR® SN6AD3 intraocular lens in refractive lens exchange demonstrated good safety, efficacy, and predictability in correcting high ametropia and presbyopia.

  3. Lens thickness assessment: anterior segment optical coherence tomography versus A-scan ultrasonography

    Directory of Open Access Journals (Sweden)

    Nikoo Hamzeh

    2015-12-01

    Full Text Available AIM: To assess lens thickness measurements with anterior segment-optical coherence tomography (AS-OCT in comparison with A-scan ultrasonography (A-scan US. METHODS: There were 218 adult subjects (218 eyes aged 59.2±9.2y enrolled in this prospective cross-sectional study. Forty-three eyes had open angles and 175 eyes had narrow angles. Routine ophthalmic exam was performed and nuclear opacity was graded using the Lens Opacities Classification System III (LOCS III. Lens thickness was measured by AS-OCT (Visante OCT, Carl Zeiss Meditec, Dublin, CA, USA. The highest quality image was selected for each eye and lens thickness was calculated using ImageJ software. Lens thickness was also measured by A-scan US. RESULTS: Interclass correlations showed a value of 99.7% for intra-visit measurements and 95.3% for inter-visit measurements. The mean lens thickness measured by AS-OCT was not significantly different from that of A-scan US (4.861±0.404 vs 4.866±0.351 mm, P=0.74. Lens thickness values obtained from the two instruments were highly correlated overall (Pearson correlation coefficient=0.81, P<0.001, and in all LOCS III specific subgroups except in grade 5 of nuclear opacity. Bland-Altman analysis revealed a 95% limit of agreement from -0.45 to 0.46 mm. Lens thickness difference between the two instruments became smaller as the lens thickness increased and AS-OCT yielded smaller values than A-scan US in thicker lens (β=-0.29, P<0.001 CONCLUSION: AS-OCT-derived lens thickness measurement is valid and comparable to the results obtained by A-scan US. It can be used as a reliable noncontact method for measuring lens thickness in adults with or without significant cataract.

  4. Stretchable Binary Fresnel Lens for Focus Tuning

    NARCIS (Netherlands)

    Li, X.; Wei, L.; Poelma, R.H.; Vollebregt, S.; Wei, J.; Urbach, Paul; Sarro, P.M.; Zhang, G.Q.

    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

  5. 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 Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1400 Maddox lens. (a) Identification. A Maddox lens is a device...

  6. Crystalline lens power and refractive error.

    Science.gov (United States)

    Iribarren, Rafael; Morgan, Ian G; Nangia, Vinay; Jonas, Jost B

    2012-02-01

    To study the relationships between the refractive power of the crystalline lens, overall refractive error of the eye, and degree of nuclear cataract. All phakic participants of the population-based Central India Eye and Medical Study with an age of 50+ years were included. Calculation of the refractive lens power was based on distance noncycloplegic refractive error, corneal refractive power, anterior chamber depth, lens thickness, and axial length according to Bennett's formula. The study included 1885 subjects. Mean refractive lens power was 25.5 ± 3.0 D (range, 13.9-36.6). After adjustment for age and sex, the standardized correlation coefficients (β) of the association with the ocular refractive error were highest for crystalline lens power (β = -0.41; P lens opacity grade (β = -0.42; P lens power (β = -0.95), lower corneal refractive power (β = -0.76), higher lens thickness (β = 0.30), deeper anterior chamber (β = 0.28), and less marked nuclear lens opacity (β = -0.05). Lens thickness was significantly lower in eyes with greater nuclear opacity. Variations in refractive error in adults aged 50+ years were mostly influenced by variations in axial length and in crystalline lens refractive power, followed by variations in corneal refractive power, and, to a minor degree, by variations in lens thickness and anterior chamber depth.

  7. 21 CFR 886.3600 - Intraocular lens.

    Science.gov (United States)

    2010-04-01

    ... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification. An intraocular lens is a device made of materials such as glass or plastic intended to be implanted to replace the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a...

  8. Transglutaminase involvement in UV-A damage to the eye lens

    International Nuclear Information System (INIS)

    Weinreb, Orly; Dovrat, A.

    1996-01-01

    Solar radiation is believed to be one of the major environmental factors involved in lens cataractogenesis. The purpose of the study was to investigate the mechanisms by which UV-A at 365 nm causes damage to the eye lens. Bovine lenses were placed in special culture cells for pre-incubation of 24 hr. The lenses were positioned so that the anterior surface faced the incident UV-A radiation source and were maintained in the cells during irradiation. After irradiation, lens optical quality was monitored throughout the culture period and lens epithelium, cortex and nuclear samples were taken for biochemical analysis. Transglutaminase activity in the lens was affected by the radiation. The activity of transglutaminase in lens epithelium cortex and nucleus increased as a result of the irradiation and then declined towards control levels during the culture period, as the lens recovered from the UV-A damage. Specific lens proteins αB and βB1 crystallins (the enzyme substrates) were analyzed by SDS polyacrylamid gel electrophoreses and immunoblotting with specific antibodies. Seventy-two hours after irradiation of 44.8 J cm -2 UV-A, αB crystallins were affected as was shown by the appearance of aggregation and degradation products. Some protein changes seem to be reversible. It appears that transglutaminase may be involved in the mechanism by which UV-A causes damage to the eye lens. (Author)

  9. Physical changes in bovine lens homogenate following ultraviolet irradiation and their prevention by some compounds

    International Nuclear Information System (INIS)

    Ohmori, Shinji; Nose, Hideko

    1985-01-01

    Exposure of the dialyzed supernatant of bovine lens homogenate to ultraviolet (UV) light led to increases in its turbidity, pigmentation, and viscosity. These photochemically induced alterations of lens proteins were prevented by glutathione, cysteine and N-acetylcysteine, but not by ascorbic acid, S-(1,2-dicarboxyethyl)-glutathione or dulcitol. (author)

  10. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  11. ECTOPIC LENS EXTRACTION IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2002-12-01

    Full Text Available Background. Ectopia lentis continues to be a therapeutic challenge for ophthalmologists. It can occur as an isolated condition, after ocular trauma, in association with other ocular disorders, as part of a systemic mesodermal disease or a complication of general metabolic disorders. Minimal subluxation of the lens may cause no visual symptoms, but in more advanced cases serious optical disturbances arise. The most important is amblyopia. Surgical treatment options include iris manipulation, lens discission, aspiration, intracapsular or extracapsular extraction, and pars plana lensectomy. The choice of surgical technique remains controversial, in part because of the historically poor visual results and high rate of perioperative complications, including vitreous loss and retinal detachment.Methods. We describe a surgical technique based on the use of the Cionni endocapsular tension ring, dry irrigation aspiration of lens material, centration of the capsular bag and foldable intraocular lens implantation into the bag. With mentioned surgical technique 8 patients were operated; 4 boys and 4 girls, together 11 eyes.Results. The final BCVA after follow up period improved in 9 eyes and it remained the same as before operation in one eye. Statistical comparison of preoperative and postoperative visual acuities showed significant improvement. On the other hand there was no correlation between preoperative and postoperative visual acuity.Conclusions. This surgical procedure is an alternative approach in solving this challenging cases of ectopia lentis with good postoperative visual rehabilitation.

  12. Temperatures of exploding nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Serfling, V.; Schwarz, C.; Begemann-Blaich, M.; Fritz, S.; Gross, C.; Kleinevoss, U.; Kunze, W.D; Lynen, U.; Mahi, M.; Mueller, W.F.J.; Odeh, T.; Schnittker, M.; Trautmann, W.; Woerner, A.; Xi, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Bassini, R.; Iori, I.; Moroni, A.; Petruzzelli, F. [Milan Univ. (Italy). Ist. di Scienze Fisiche]|[Istituto Nazionale di Fisica Nucleare, Milan (Italy); Gaff, S.J.; Kunde, G.J. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy]|[Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Imme, G.; Maddalena, V.; Nociforo, C.; Raciti, G.; Riccobene, G.; Romano, F.P.; Saija, A.; Sfienti, C.; Verde, G. [Catania Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Catania (Italy); Moehlenkamp, T.; Seidel, W. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany); Ocker, B.; Schuettauf, A. [Frankfurt Univ. (Germany). Inst. fuer Kernphysik; Pochodzalla, J. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Trzcinski, A.; Zwieglinski, B. [Soltan Inst. for Nuclear Studies, Warsaw (Poland)

    1998-01-01

    Breakup temperatures in central collisions of {sup 197}Au+{sup 197}Au at bombarding energies E/A=50 to 200 MeV were determined with two methods. Isotope temperatures, deduced from double ratios of hydrogen, helium, and lithium isotopic yields, increase monotonically with bombarding energy from 5 MeV to 12 MeV, in qualitative agreement with a scenario of chemical freeze-out after adiabatic expansion. Excited-state temperatures, derived from yield ratios of states in {sup 4}He, {sup 5,6}Li, and {sup 8}Be, are about 5 MeV, independent of the projectile energy, and seem to reflect the internal temperature of fragments at their final separation from the system. (orig.)

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

    Directory of Open Access Journals (Sweden)

    Meyer Rita A

    2007-06-01

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

  14. Customer loyalty among daily disposable contact lens wearers.

    Science.gov (United States)

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

    2015-02-01

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

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

    Science.gov (United States)

    Yang, Jian; Cen, Zhaofeng; Li, Xiaotong

    2018-01-01

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

  16. Cavitation nuclei measurements - A review

    International Nuclear Information System (INIS)

    Billet, M.L.

    1985-01-01

    The measurement of cavitation nuclei has been the goal of many cavitation research laboratories and has resulted in the development of many methods. Two significantly different approaches have been developed. One is to measure the particulate-microbubble distribution by utilizing acoustical, electrical or optical methods. The other approach measures a liquid tension and a rate of cavitation events for a liquid in order to establish a cavitation susceptibility. Comparisons between various methods indicate that most methods are capable of giving an indication of the nuclei distribution. Measurements obtained in the ocean environment indicate an average of three bubbles per cubic centimeter are present; whereas, water tunnel bubble distributions vary from much less than one to over a hundred per cubic centimeter

  17. Phonon operators in deformed nuclei

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1981-01-01

    For the description of the excited states in deformed nuclei new phonon operators are introduced, which depend on the sign of the angular momentum projection onto the symmetry axis of a deformed nucleus. In the calculations with new phonons the Pauli principle is correctly taken into account in the two-phonon components of the wave functions. There is a difference in comparison with the calculation with phonons independent of the sign of the angular momentum projection. The new phonons should be used in deformed nuclei if the Pauli principle is consistently taken into account and in the calculations with the excited state wave functions having the components with more than one phonon operator [ru

  18. Phonon operators for deformed nuclei

    International Nuclear Information System (INIS)

    Solov'ev, V.G.

    1982-01-01

    The mathematical formalism with the phonon operators independent of the signature of the angular momentum projection turns out to be inadequate for describing excited states of deformed nuclei. New phonon operators are introduced which depend on the signature of the angular momentum projection on the symmetry axis of a deformed nucleus. It is shown that the calculations with the new phonons take correctly into account the Pauli principle in two-phonon components of wave functions. The results obtained differ from those given by the phonons independent of the signature of the angular momentum projection. The new phonons must be used in deformed nuclei at taking systematically the Pauli principle into account and in calculations involving wave functions of excited states having components with more than one-phonon operator

  19. Nuclear treasure island [superheavy nuclei

    CERN Document Server

    CERN. Geneva

    1999-01-01

    Summary form only given. Soon after the experiments at Dubna, which synthesized element 114 and made the first footprints on the beach of the "island of nuclear stability", two new superheavy elements have been discovered at the Lawrence Berkeley National Laboratory. Element 118 and its immediate decay product, element 116, were manufactured at Berkeley's 88 inch cyclotron by fusing targets of lead-208 with an intense beam of 449 MeV krypton-86 ions. Although both new nuclei almost instantly decay into lighter ones, the decay sequence is consistent with theories that have long predicted the island of stability for nuclei with approximately 114 protons and 184 neutrons. Theorist Robert Smolanczuk, visiting from the Soltan Institute for Nuclear Studies in Poland, had calculated that this reaction should have particularly favourable production rates. Now that this route has been signposted, similar reactions could be possible: new elements and isotopes, tests of nuclear stability and mass models, and a new under...

  20. Moessbauer effects on oriented nuclei

    International Nuclear Information System (INIS)

    Sayouti, E.H.

    1984-01-01

    Standard nuclear orientation methods (not sensitive to the polarization) do not give information on the sign of the magnetic moment. Mossbauer effect separates right-hand and left-hand circularly polarized components, thus its detection on oriented nuclei (T approximately 10 mK) gives the sign of the magnetic moment of oriented state. In this thesis we applied this method to study the 3/2 - ground states of 191 Pt and 193 Os, which are in the prolate-oblate transition region, where assignement of experimental levels to theoretical states is often umbiguous. We show that for those nuclei the sign of the magnetic moment is the signature of the configuration, and its determination establishes the correspondance between experimental and theoretical levels [fr

  1. Clusters in nuclei. Vol. 1

    International Nuclear Information System (INIS)

    Beck, Christian

    2010-01-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is presently one of the domains of heavy-ion nuclear physics facing both the greatest challenges and opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physics decided to team up in producing a comprehensive collection of lectures and tutorial reviews covering the field. This first volume, gathering seven extensive lectures, covers the follow topics: - Cluster Radioactivity - Cluster States and Mean Field Theories - Alpha Clustering and Alpha Condensates - Clustering in Neutron-rich Nuclei - Di-neutron Clustering - Collective Clusterization in Nuclei - Giant Nuclear Molecules By promoting new ideas and developments while retaining a pedagogical nature of presentation throughout, these lectures will both serve as a reference and as advanced teaching material for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  2. 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

  3. Mesons and quarks in nuclei

    International Nuclear Information System (INIS)

    Oset, E.

    1980-01-01

    A short review of the topic of mesons in nuclei is exposed paying particular attention to the relationship between several mesonic processes. Special emphasis is put into the microscopic pictures that can ultimately relate all these processes with the elementary coupling of mesons to the nuclear hadronic components. The importance of the short range part of the nuclear interaction opens the doors to a more basic understanding in terms of the quark components of nucleons and isobars. (orig.)

  4. Exclusive photoreactions on light nuclei

    International Nuclear Information System (INIS)

    Maruyama, K.

    1989-08-01

    The mechanism of photon absorption on light nuclei in the Δ-resonance region is discussed. The present status of experimental results is briefly summarized. A recent data from 1.3-GeV Tokyo ES using a π sr spectrometer is introduced. Exclusive measurements of the photodisintegration of 3 He and 4 He may be a clear way to identify 2N, 3N and 4N absorptions. (author)

  5. Fission barriers of light nuclei

    International Nuclear Information System (INIS)

    Grotowski, K.; Planeta, R.; Blann, M.; Komoto, T.

    1989-01-01

    Experimental fission excitation functions for compound nuclei /sup 52/Fe, /sup 49/Cr, /sup 46/V, and /sup 44/Ti formed in heavy-ion reactions are analyzed in the Hauser-Feshbach/Bohr-Wheeler formalism using fission barriers based on the rotating liquid drop model of Cohen et al. and on the rotating finite range model of Sierk. We conclude that the rotating finite range approach gives better reproduction of experimental fission yields, consistent with results found for heavier systems

  6. Shell closures, loosely bound structures, and halos in exotic nuclei

    International Nuclear Information System (INIS)

    Saxena, G.; Singh, D.

    2013-01-01

    Inspired by the recent experiments indicating doubly magic nuclei that lie near the drip-line and encouraged by the success of our relativistic mean-field (RMF) plus state-dependent BCS approach to the description of the ground-state properties of drip-line nuclei, we develop this approach further, across the entire periodic table, to explore magic nuclei, loosely bound structures, and halo formation in exotic nuclei. In our RMF+BCS approach, the single-particle continuum corresponding to the RMF is replaced by a set of discrete positive-energy states for the calculations of pairing energy. Detailed analysis of the single-particle spectrum, pairing energies, and densities of the nuclei predict the unusual proton shell closures at proton numbers Z = 6, 14, 16, 34, and unusual neutron shell closures at neutron numbers N = 6, 14, 16, 34, 40, 70, 112. Further, in several nuclei like the neutron-rich isotopes of Ca, Zr, Mo, etc., the gradual filling of lowlying single-particle resonant state together with weakly bound single-particle states lying close to the continuum threshold helps accommodate more neutrons but with an extremely small increase in the binding energy. This gives rise to the occurrence of loosely bound systems of neutron-rich nuclei with a large neutron-to-proton ratio. In general, the halo-like formation, irrespective of the existence of any resonant state, is seen to be due to the large spatial extension of the wave functions for the weakly bound single-particle states with low orbital angular momentum having very small or no centrifugal barriers.

  7. Shell closures, loosely bound structures, and halos in exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, G., E-mail: gauravphy@gmail.com [Govt. Women Engineering College, Department of Physics (India); Singh, D. [University of Rajasthan, Department of Physics (India)

    2013-04-15

    Inspired by the recent experiments indicating doubly magic nuclei that lie near the drip-line and encouraged by the success of our relativistic mean-field (RMF) plus state-dependent BCS approach to the description of the ground-state properties of drip-line nuclei, we develop this approach further, across the entire periodic table, to explore magic nuclei, loosely bound structures, and halo formation in exotic nuclei. In our RMF+BCS approach, the single-particle continuum corresponding to the RMF is replaced by a set of discrete positive-energy states for the calculations of pairing energy. Detailed analysis of the single-particle spectrum, pairing energies, and densities of the nuclei predict the unusual proton shell closures at proton numbers Z = 6, 14, 16, 34, and unusual neutron shell closures at neutron numbers N = 6, 14, 16, 34, 40, 70, 112. Further, in several nuclei like the neutron-rich isotopes of Ca, Zr, Mo, etc., the gradual filling of lowlying single-particle resonant state together with weakly bound single-particle states lying close to the continuum threshold helps accommodate more neutrons but with an extremely small increase in the binding energy. This gives rise to the occurrence of loosely bound systems of neutron-rich nuclei with a large neutron-to-proton ratio. In general, the halo-like formation, irrespective of the existence of any resonant state, is seen to be due to the large spatial extension of the wave functions for the weakly bound single-particle states with low orbital angular momentum having very small or no centrifugal barriers.

  8. Radii of nuclei off stability

    International Nuclear Information System (INIS)

    Sugimoto, Kenzo

    1982-01-01

    An experiment is proposed to determine systematically the radii of the nuclei produced through the projectile fragmentation process in high energy heavy-ion collision. The measurement of total reaction cross section using the projectile fragments of a single nuclide on a target give information about nuclear radii. The production cross section of the fragments is appreciable for many nuclides. Therefore, it is possible to map systematically the reaction radii of the nuclei which can be produced as the projectile fragments. In an experiment using the projectile fragments as the incident beam, the cross section can be expressed as a function of the radii of a projectile and a target. An experiment with He-8 produced by the fragmentation of C-12 is proposed. The He-8 has four neutrons in the p-3/2 orbit outside the He-4 core. Proton and neutron distributions for He isotopes were calculated on the basis of the Hartree-Fock method. The information related to this kind of distribution can be obtained by the proposed experiment. The nuclear structure effect is seen in the nuclear radii of other unstable nuclei. The experimental examples of the isotope shift measurement and the excitation energy are presented. (Kato, T.)

  9. Density functional theory of nuclei

    International Nuclear Information System (INIS)

    Terasaki, Jun

    2008-01-01

    The density functional theory of nuclei has come to draw attention of scientists in the field of nuclear structure because the theory is expected to provide reliable numerical data in wide range on the nuclear chart. This article is organized to present an overview of the theory to the people engaged in the theory of other fields as well as those people in the nuclear physics experiments. At first, the outline of the density functional theory widely used in the electronic systems (condensed matter, atoms, and molecules) was described starting from the Kohn-Sham equation derived on the variational principle. Then the theory used in the field of nuclear physics was presented. Hartree-Fock and Hartree-Fock-Bogolyubov approximation by using Skyrme interaction was explained. Comparison of the results of calculations and experiments of binding energies and ground state mean square charge radii of some magic number nuclei were shown. The similarity and dissimilarity between the two streams were summarized. Finally the activities of the international project of Universal Nuclear Energy Density Functional (UNEDF) which was started recently lead by US scientist was reported. This project is programmed for five years. One of the applications of the project is the calculation of the neutron capture cross section of nuclei on the r-process, which is absolutely necessary for the nucleosynthesis research. (S. Funahashi)

  10. Thermodynamical description of excited nuclei

    International Nuclear Information System (INIS)

    Bonche, P.

    1989-01-01

    In heavy ion collisions it has been possible to obtain composite systems at rather high excitation energies corresponding to temperatures of several MeV. The theoretical studies of these systems are based on concepts borrowed from thermodynamics or statistical physics, such as the temperature. In these lectures, we present the concepts of statistical physics which are involved in the physics of heavy ion as they are produced nowadays in the laboratory and also during the final stage of a supernova collapse. We do not attempt to describe the reaction mechanisms which yield such nuclear systems nor their decay by evaporation or fragmentation. We shall only study their static properties. The content of these lectures is organized in four main sections. The first one gives the basic features of statistical physics and thermodynamics necessary to understand quantum mechanics at finite temperature. In the second one, we present a study of the liquid-gas phase transition in nuclear physics. A phenomenological approach of the stability of hot nuclei follows. The microscopic point of view is proposed in the third part. Starting from the basic concepts derived in the first part, it provides a description of excited or hot nuclei which confirms the qualitative results of the second part. Furthermore it gives a full description of most properties of these nuclei as a function of temperature. Finally in the last part, a microscopic derivation of the equation of state of nuclear matter is proposed to study the collapse of a supernova core

  11. Exotic Nuclei and Yukawa's Forces

    International Nuclear Information System (INIS)

    Otsuka, Takaharu; Suzuki, Toshio; Utsuno, Yutaka

    2008-01-01

    In this plenary talk, we will overview the evolution of the shell structure in stable and exotic nuclei as a new paradigm of nuclear structure physics. This shell evolution is primarily due to the tensor force. The robust mechanism and some examples will be presented. Such examples include the disappearance of existing magic numbers and the appearance of new ones. The nuclear magic numbers have been believed, since Mayer and Jensen, to be constants as 2, 8, 20, 28, 50, ... This turned out to be changed, once we entered the regime of exotic nuclei. This shell evolution develops at many places on the nuclear chart in various forms. For example, superheavy magic numbers may be altered. Thus, we are led to a new paradigm as to how and where the nuclear shell evolves, and what consequences arise. The evolution of the shell affects weak process transitions, and plays a crucial role in deformation. The π and ρ mesons generate tensor forces, and are the fundamental elements of such intriguing phenomena. Thus, physics of exotic nuclei arises as a manifestation of Yukawa's forces

  12. Development of a Laue lens for nuclear astrophysics

    International Nuclear Information System (INIS)

    Barriere, N.

    2008-04-01

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

  13. Lens decenter and tilt measurement by interferogram

    Science.gov (United States)

    Hung, Min-Wei; Wu, Wen-Hong; Huang, Kuo-Cheng

    2009-11-01

    For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.

  14. Plasma Lens for Muon and Neutrino Beams

    Science.gov (United States)

    Kahn, Stephen; Korenev, Sergey; Bishai, Mary; Diwan, Milind; Gallardo, Juan; Hershcovitch, Ady; Johnson, Brant

    2008-04-01

    The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-current lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. A plasma lens has additional advantage: larger axial current than horns, minimal neutrino contamination during antineutrino running, and negligible pion absorption or scattering. Results from particle simulations using a plasma lens will be presented.

  15. The colours of Hubble Sc galaxy nuclei

    International Nuclear Information System (INIS)

    Iskudaryan, S.G.

    1975-01-01

    The colorimetric data on the nuclei of the Sc galaxies are given. Comparison of the following parameters: color of a nucleus, integral color of a galaxy, Byurakan class, and spectral type of normal spirals gives the possibility to conclude: (1) The colors of the nuclei of the Sc galaxies have a high dispersion in its values. In all Byurakan classes the galaxies with intensely red and blue nuclei occur; (2) Some Sc galaxies exhibit a discrepancy between the spectral and morphological types. The results of colorimetry of nuclei indicate that almost all such Sc galaxies have intensely red nuclei which, naturally, provide for these late spectral types. It can be assumed that the intensely red color of the nuclei of such Sc galaxies is a result of a new type of activity of these nuclei; and (3) some Sc galaxies show the characteristics of the Markarian objects

  16. A novel lens epithelium gene, LEP503, is highly conserved in different vertebrate species and is developmentally regulated in postnatal rat lens.

    Science.gov (United States)

    Wen, Y; Sachs, G; Athmann, C

    2000-02-01

    The development of the lens is dependent on the proliferation of lens epithelial cells and their differentiation into fiber cells near the lens bow/equator. Identification of genes specifically expressed in the lens epithelial cells and their functions may provide insight into molecular events that regulate the processes of lens epithelial cell differentiation. In this study, a novel lens epithelium gene product, LEP503, identified from rat by a subtractive cDNA cloning strategy was investigated in the genome organization, mRNA expression and protein localization. The genomic sequences for LEP503 isolated from rat, mouse and human span 1754 bp, 1694 bp and 1895 bp regions encompassing the 5'-flanking region, two exons, one intron and 3'-flanking region. All exon-intron junction sequences conform to the GT/AG rule. Both mouse and human LEP503 genes show very high identity (93% for mouse and 79% for human) to rat LEP503 gene in the exon 1 that contains an open reading frame coding for a protein of 61 amino acid residues with a leucine-rich domain. The deduced protein sequences also show high identity (91% between mouse and rat and 77% between human and rat). Western blot shows that LEP503 is present as a specific approximately 6.9 kDa band in the water-insoluble-urea-soluble fraction of lens cortex where lens epithelium is included. Immuno-staining shows that LEP503 is localized in the epithelial cells along the entire anterior surface of rat lens. Developmentally, LEP503 is expressed at a low level at newborn, and then the expression level increases by about ten-fold around postnatal day 14 and remains at this high level for about 25 days before it drops back to the low level by postnatal day 84. These data suggest that the LEP503 may be an important lens epithelial cell gene involving the processes of epithelial cell differentiation. Copyright 2000 Academic Press.

  17. Nonlinear laser pulse response in a crystalline lens.

    Science.gov (United States)

    Sharma, R P; Gupta, Pradeep Kumar; Singh, Ram Kishor; Strickland, D

    2016-04-01

    The propagation characteristics of a spatial Gaussian laser pulse have been studied inside a gradient-index structured crystalline lens with constant-density plasma generated by the laser-tissue interaction. The propagation of the laser pulse is affected by the nonlinearities introduced by the generated plasma inside the crystalline lens. Owing to the movement of plasma species from a higher- to a lower-temperature region, an increase in the refractive index occurs that causes the focusing of the laser pulse. In this study, extended paraxial approximation has been applied to take into account the evolution of the radial profile of the Gaussian laser pulse. To examine the propagation characteristics, variation of the beam width parameter has been observed as a function of the laser power and initial beam radius. The cavitation bubble formation, which plays an important role in the restoration of the elasticity of the crystalline lens, has been investigated.

  18. Expression of c-Fos and c-Jun in the cornea, lens, and retina after ultraviolet irradiation of the rat eye and effect of topical antisense oligodeoxynucleotides

    International Nuclear Information System (INIS)

    Gillardon, F.; Zimmermann, M.

    1995-01-01

    Aims - Immunohistochemical techniques were used to investigate c-Fos and c-Jun proto-oncogene expression in the cornea, lens, and retina after ultraviolet irradiation of the rat eye. Methods -Eyes of anaesthetised rats were exposed to 1.5 J/cm 2 of ultraviolet radiation (280-380 nm). Animals were perfused 1, 6, or 24 hours after irradiation and tissue sections were incubated with specific antiserum to c-Fos and c-Jun, respectively. Non-irradiated contralateral eyes displayed no c-Fos and c-Jun immunoreactivity. One and 6 hours after ultraviolet exposure numerous c-Fos and c-Jun immunopositive nuclei were observed mainly in the epithelial cell layers of the cornea and the lens epithelium. Scattered labelled nuclei were detectable in the retinal ganglion cell layer and the inner nuclear layer. Twenty four hours after irradiation c-Fos and c-Jun protein expression returned to near control levels. Histological signs of ultraviolet damage (for example, chromatin condensation, nuclear fragmentation) were first recognisable in the corneal epithelium 6 hours after irradiation and became more apparent at later times. The rapid and sustained activation of c-Fos and c-Jun expression in the eye after single ultraviolet exposure may represent the molecular mechanism underlying ultraviolet induced photodamage and initiation of cell death. Furthermore, topical application of a c-fos antisense oligode-oxynucleotide to the ultraviolet exposed rat eye inhibited the increase in c-Fos expression in the cornea, suggesting therapeutic activity of antisense drugs in corneal malignant and infectious diseases. (author)

  19. Oral Morphine Consumption Reduces Lens Development in Rat Embryos

    Directory of Open Access Journals (Sweden)

    Hossein Bahadoran

    2012-07-01

    Full Text Available Objective: Consumption of morphine, during pregnancy, in addition to inducing defects in the mother’s nervous system function, caused defects or delays in the formation and evolution of embryonic visual system. In the present study, changes in lens development was assessed in embryos exposed in utero to morphine. Material and Methods: Female Wistar rats (250-300 g were mated with male rats and pregnancy was determined by sperm observation in vaginal smear. This day was considered as embryonic day zero (E0. The females were then divided randomly into the experimental and the control groups. The control group received tap water and the experimental group received morphine (0.05 mg/ml in their water. On embryonic day 13 ( E13, blood samples were collected from the retro-orbital sinus of all animals for plasma corticosterone detection. On embryonic day 17(E17, the animals were killed by an overdose of chloroform and the embryos were taken out surgically. The embryos were fixed in 10% formalin for 30 days. At this time, the head of the embryos were removed for tissue processing and Hematoxylin- Eosin (H&E staining. The samples were evaluated using light microscope and MOTIC software. Results: Our data indicated that plasma corticosterone level was dramatically increased and the lens was thinner in the experimental group. (Although the proliferation of lens cells increased in the experiment group but that lens had delay in removing the proliferated and elongation cells with abnormal density in the lateral part of the lens in compare with control group. I have no idea what the authors are stating here. Moreover, the opening of the eyelids was delayed in the off springs of the mothers who received morphine. Conclusions: This study showed that morphine consumption during pregnancy leads to defects in fetal visual system development, particularly in the lens, and eyelids.

  20. Acanthamoeba keratitis in Scotland: risk factors for contact lens wearers.

    Science.gov (United States)

    Seal, D V; Kirkness, C M; Bennett, H G; Peterson, M

    1999-01-01

    To investigate risk factors for Acanthamoeba keratitis amongst contact lens wearers in Scotland. Patients with Acanthamoeba keratitis in the Scottish study, all of whom wore contact lenses, were compared with 46 healthy asymptomatic contact lens-wearing controls. They were all visited at home for contact lens and environmental microbiological sampling. In addition, all 288 optical practices in the West of Scotland were polled for contact lens types and disinfecting solutions sold in 1995, and a sample, each of whom fitted more than 500 contact lenses per year, were polled for a second time. Independently, a poll was commissioned by the Eyecare Information Service in July/August 1995 to estimate the numbers of contact lens wearers in Scotland and the UK. Industry was polled for numbers of each contact lens disinfecting regimen sold in Scotland in 1995. West of Scotland, UK. All contact lens wearers among the 3 million population of the West of Scotland Health Board Areas. Risk factors for Acanthamoeba infection and recommendations for its prevention. When Acanthamoeba infection occurred, patients' home water systems were frequently (54%) found to be colonised by this amoeba. Patients more frequently washed their storage cases in tap water than controls (Pmethods (chlorine tablets or no disinfection). However further investigation showed that these methods were associated with an increased probability of rinsing the storage case in tap water, so that these two behaviours are confounded in the group studied. Failure to disinfect contact lenses, non-compliant use of chlorine tablets and/or introduction of tap water rinsing of storage cases were associated with increased risk of Acanthamoeba infection. New multipurpose solutions and hydrogen peroxide gave the lowest risk of Acanthamoeba infection, with no statistically significant difference between them. Ionic high-water content (FDA group 4) contact lenses were at increased risk of being associated with Acanthamoeba

  1. Role of neutrons in the fusion of nuclei

    International Nuclear Information System (INIS)

    Zagrebaev, V. I.; Samarin, V. V.

    2007-01-01

    The problem of a quantum-mechanical description of a near-barrier fusion of heavy nuclei under conditions of a strong coupling of their relative motion to neutron degrees of freedom is studied. New mutually complementing efficient models employing the multidimensional time-dependent Schroedinger equation and methods for numerically solving the problems in question within these models are proposed. This makes it possible to study the evolution of wave functions for outer neutrons and to calculate nucleon transfer probabilities and occupation numbers for quasimolecular states over the entire energy range, including that of deep-subbarrier energies. It is shown that the valence-neutron wave functions extend over the volumes of both colliding nuclei before their surfaces come into contact and even before these nuclei overcome the Coulomb barrier (collectivization of outer nucleons). This gives rise to a substantial neutron-transfer effect on the fusion of nuclei and, in particular, to a sizable increase in the probability of subbarrier fusion for specific combinations of nuclei

  2. Topology of White Stars in Relativistic Fragmentation of Light Nuclei

    CERN Document Server

    Andreeva, N P; Vokal, S; Vokalova, A; Gaitinov, A Sh; Gerassimov, S G; Goncharova, L A; Dronov, V A; Zarubin, P I; Zarubina, I G; Kovalenko, A D; Kravchakova, A; Larionova, V G; Levitskaja, O V; Lepehin, F G; Malakhov, A I; Moiseenko, A A; Orlova, G I; Peresadko, N G; Polukhina, N G; Rukojatkin, P A; Rusakova, V V; Salmanova, N A; Sarkisian, V R; Simonov, B B; Stan, E; Stanoeva, R; Chernyavsky, M M; Haidue, M; Kharlamov, S P; Tsakov, I; Shchedrina, T V

    2004-01-01

    In the present paper, experimental observation of the multifragmentation processes of light relativistic nuclei carried out by means of emulsions are reviewed. Events of the type of "white stars" in which the dissociation of relativistic nuclei is not accompanied by the production of mesons and the target-nucleus fragments are considered. A distinctive feature of the charge topology in the dissociation of the Ne, Mg, Si and S nuclei is an almost total suppression of the binary splitting of nuclei to fragments with charges higher than 2. The growth of the nuclear fragmentation degree is revealed in an increase in the multiplicity of singly and doubly charged fragments with decreasing charge of the main non-excited part of the fragmenting nucleus. The processes of dissociation of stable Li, Be, B, C, N, and O isotopes to charged fragments were used to study special features of the formation of systems consisting of the lightest nuclei - alpha, d and t. Clustering of the 3He nucleus can be detected in "white sta...

  3. Synthesis and radioactive properties of the heaviest nuclei

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.

    1996-01-01

    Experimental investigations on the synthesis and study of properties of faraway transactinide elements confirm the predictions of macro-microscopic theory on the existence of closed shells in the region of heavy deformed nuclei. It has been demonstrated experimentally that nuclear structure plays a decisive role in the stability of superheavy nuclides. Based on the experimental confirmation of the main provisions of the theory and after the introduction of a necessary correction into the calculation the properties of heavier nuclides in the region of spherical shells Z=114 and N=180-184 have been predicted. Here a substantial increase in the stability of nuclei is also expected. All the nuclei synthesized by now, were obtained in fusion reactions with a formation of a compound nucleus, the transition of which to the ground state takes place with the emission of neutrons and gamma-rays. Both the reactions of cold and hot fusion of nuclei can be used for the synthesis of new nuclei. Nevertheless, new experimental data on the fusion mechanism are required, since a number of theoretical descriptions of the fusion dynamics of complex nuclear systems need a substantial revising. One can assume that the reactions of the type 244 Pu, 248 Cm + 48 Ca are still within the current potential of the accelerators and experimental technique. This potential, nevertheless, is still to be implemented. 37 refs., 6 figs

  4. LC-lens array with light field algorithm for 3D biomedical applications

    Science.gov (United States)

    Huang, Yi-Pai; Hsieh, Po-Yuan; Hassanfiroozi, Amir; Martinez, Manuel; Javidi, Bahram; Chu, Chao-Yu; Hsuan, Yun; Chu, Wen-Chun

    2016-03-01

    In this paper, liquid crystal lens (LC-lens) array was utilized in 3D bio-medical applications including 3D endoscope and light field microscope. Comparing with conventional plastic lens array, which was usually placed in 3D endoscope or light field microscope system to record image disparity, our LC-lens array has higher flexibility of electrically changing its focal length. By using LC-lens array, the working distance and image quality of 3D endoscope and microscope could be enhanced. Furthermore, the 2D/3D switching ability could be achieved if we turn off/on the electrical power on LClens array. In 3D endoscope case, a hexagonal micro LC-lens array with 350um diameter was placed at the front end of a 1mm diameter endoscope. With applying electric field on LC-lens array, the 3D specimen would be recorded as from seven micro-cameras with different disparity. We could calculate 3D construction of specimen with those micro images. In the other hand, if we turn off the electric field on LC-lens array, the conventional high resolution 2D endoscope image would be recorded. In light field microscope case, the LC-lens array was placed in front of the CMOS sensor. The main purpose of LC-lens array is to extend the refocusing distance of light field microscope, which is usually very narrow in focused light field microscope system, by montaging many light field images sequentially focusing on different depth. With adjusting focal length of LC-lens array from 2.4mm to 2.9mm, the refocusing distance was extended from 1mm to 11.3mm. Moreover, we could use a LC wedge to electrically shift the optics axis and increase the resolution of light field.

  5. Immunoglobulin Concentration in Tears of Contact Lens Wearers

    Directory of Open Access Journals (Sweden)

    Rajendra P Maurya

    2014-01-01

    Conclusion: The relation of immunoglobulin concentration with increasing duration of wear and material of contact lens shows that tear immunoglobulin rise accrues due to mechanical stimulation, hence contact lenses should not be used for a long period and lenses of hard nature should be discouraged. The maintenance, cleaning and deproteinization of the lenses are of high importance to avoid immunostimulation.

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  7. Equivalent refractive index of the human lens upon accommodative response

    NARCIS (Netherlands)

    Hermans, E.A.; Dubbelman, M.; van der Heijde, R.G.L.; Heethaar, R.M.

    2008-01-01

    PURPOSE.: To experimentally verify the suggestion of Gullstrand (1909), i.e., that the equivalent refractive index of the human lens increases with accommodation. METHODS.: The left eye of five subjects was focused on different accommodation stimuli, while the right eye was imaged with Scheimpflug

  8. Statistics of hits to bone cell nuclei

    International Nuclear Information System (INIS)

    Kruglikov, I.L.; Polig, E.; Jee, W.S.S.

    1993-01-01

    The statistics of hits to the nuclei of bone cells irradiated from alpha sources labeling bone tissue is described. It is shown that the law of remodeling of a bone structural unit (BSU), which describes the distribution of quiescence periodes of this unit, affects the statistics of hits. It the irradiation of bone cells occurs during the whole cell cycle, the mean number of hits is independent of the law of remodeling. In this case the variance of hits has the minimum value for constant quiescence periods of BSUs (deterministic remodeling) and the maximum value for exponentially distributed quiescence periods (random remodeling). For the first generation of bone cells, i.e. for the cells which existed at the moment of the uptake of the nuclide, the mean number of hits depends on the law of remodeling. For random remodeling the mean number is equal to the mean value for the complete remodeling cycle. For deterministic remodeling the mean is only half this value. For the first generation of bone cells, changing the law of remodeling from random to deterministic increases the probability of no hits to the nuclei of bone cells. For the same mean value of hits, the difference does not exceed 13.3% of the total number of cells. For the subsequent generations of bone cells, such a change of the law of remodeling decreases the probability of no hits up to 20.4% of the total number of cells. (orig.)

  9. 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.

  10. Looking beyond the perfect lens

    International Nuclear Information System (INIS)

    Wee, W H; Pendry, J B

    2010-01-01

    The holy grail of imaging is the ability to see through anything. From the conservation of energy, we can easily see that to see through a lossy material would require lenses with gain. The aim of this paper therefore is to propose a simple scheme by which we can construct a general perfect lens, with gain-one that can restore both the phases and amplitudes of near and far fields.

  11. On peculiarities of the cascade γ decay of heavy nuclei

    International Nuclear Information System (INIS)

    Boneva, S.T.; Khitrov, V.A.; Popov, Yu.P.; Sukhovoj, A.M.; Vasil'eva, E.V.; Yazvitskij, Yu.S.

    1987-01-01

    Comparison of measured and calculated by statistical theory sums of two-quanta cascade intensities in compound-nuclei 163 ≤ A ≤ 183 points to the dependence of cascade intensity on the structure of initial and intermediate levels. The dependence of two-quanta cascade intensity sum on reduced neutron widths of compound states of even-even nuclei-targets of rare earth regions is detected. In 175 Yb and 179 Hf nuclei a considerable increase in the intensity of two-quanta cascades at the energy of their intermediate level in the range of the calculated position of one-quasiparticle states of the Saxon-Woods deformed potential is observed

  12. On deuteron break-up at interaction with heavy nuclei

    International Nuclear Information System (INIS)

    Evlanov, M.V.; Nemets, O.F.; Struzhko, B.G.

    1975-01-01

    The aim of the paper is the study of the nuclear boundary diffusivity during disintegration of a deutron on heavy nuclei for various combinations of neutron and proton emission angles. The formulae has obtained for the cross section and the amplitude of nuclear interaction. The calculation of angular correlations between emission directions of deutron disintegration products and energy spectra of released protons depending on the nuclear boundary diffusivity is made. It is shown that the differential cross sections of deutron fission disintegration decrease with increasing nuclear boundary diffusivity. This effect may serve a qualitative explanation for observed differences in the deutron disintegration cross sections on heavy nuclei

  13. Reliability of the pseudospin symmetry in atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Marcos, S.; Niembro, R. [Departamento de Fisica Moderna, Universidad de Cantabria, E-39005 Santander (Spain); Lopez-Quelle, M. [Departamento de Fisica Aplicada, Universidad de Cantabria, E-39005 Santander (Spain); Savushkin, L.N. [Department of Physics, St. Petersburg University for Telecommunications, 191065 St. Petersburg (Russian Federation); Bernardos, P. [Departamento de Matematica Aplicada y Ciencias de la Computacion, Universidad de Cantabria, E-39005 Santander (Spain)

    2003-06-01

    The reliability of the pseudospin symmetry (PSS) in atomic nuclei is analyzed in the framework of the relativistic Hartree approach. We find that the nuclear surface strongly increases the effect of the pseudospin-orbit potential (PSOP), spoiling the possibility of the exact realization of the PSS even in the limit of a vanishing PSOP. It is also shown that the PSS cannot be explained by the fact that {sigma}{sub S}{approx_equal}-{sigma}. New arguments to explain the PSS in finite nuclei are given. The important role the spin-orbit interaction plays in the achievement of the PSS is also discussed. (orig.)

  14. Study on decay of rare earth nuclei produced by fission

    Energy Technology Data Exchange (ETDEWEB)

    Kawade, Kiyoshi; Yamamoto, Hiroshi; Shibata, Michihiro; Asai, Masato [Nagoya Univ. (Japan); Tsukada, Kazuaki; Osa, Akihiko; Shinohara, Nobuo; Iimura, Hideki

    1996-01-01

    JAERI-ISOL utilizes charge particle induced fission by proton and heavy proton produced by the tandem type accelerator (JAERI). To study the decay mechanism and nuclei structure of neutron and excess nuclei produced by actinoid fission, JAERI-ISOL was improved by developing the multilayer target tank. So that, the intensity of mass separated ion beam increased enough to use. New 76.6 KeV {gamma}-ray with about 10s of half life was found in the preliminary experiment. (S.Y.)

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

    International Nuclear Information System (INIS)

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

    2017-01-01

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

  16. Exotic light nuclei and nuclei in the lead region

    International Nuclear Information System (INIS)

    Poppelier, N.A.F.M.

    1989-01-01

    Three methods are discussed for modifying, or renormalizing, a truncated nuclear hamiltonian such that the wave functions obtained by diagonalizing this modified or effective hamiltoniandescribe the nucleus as well as possible: deriving the hamiltonian directly from a realistic nucleon-nucleon interaction between free nucleons; parametrizing the hamiltonian in terms of a number of parameters and determining these parameters from a least-squares fit of calculated properties to experimental data; approximating the nucleon-nucleon (NN) interaction between two nucleons in a nucleus by a simple analytic expression. An effective hamiltonian derived following the second method is applied in a theoretical study of exotic nuclei in the region of Z=2-9 and A=4-30 and the problem of the neutron halo in 11 Li is discussed. Results of shell-model calculations of 20i Pb and nuclei in its neighbourhood are presented in which an effective hamiltonian was employed derived with the last method. The quenching of M1 strength in 208 Pb, and the spectroscopic factors measured in proton knock-out reactions could be described quite satisfactory. Finally, a method is presented for deriving the effective hamiltonian directly from the realistic NN interaction with algebraic techniques. (H.W.). 114 refs.; 34 figs.; 12 tabs.; schemes

  17. The Risk of Contact Lens Wear and the Avoidance of Complications

    Directory of Open Access Journals (Sweden)

    Farihah Tariq

    2013-11-01

    Full Text Available Contact lenses are lenses placed on the surface of the cornea to correct refractive errors such as myopia (short-sightedness, hypermetropia (far-sightedness and astigmatism. Lens-related complications are becoming a greater health concern as increasing number of individuals are using them as an alternative to spectacles. Contact lenses alter the natural ocular environment and reduce the efficacy of the innate defences. Although many complications are minor, microbial keratitis is potentially blinding and suspected cases should be rapidly diagnosed and referred to an ophthalmologist for treatment. Several risk factors have been identified with extended wear, poor hand hygiene, inadequate lens and lens-case care being the most significant. Promotion of good contact lens hygiene and practices are essential to reduce the adverse effects of contact lens wear.

  18. Multiplexing Visual Signals in the Suprachiasmatic Nuclei

    Directory of Open Access Journals (Sweden)

    Adam R. Stinchcombe

    2017-11-01

    Full Text Available The suprachiasmatic nuclei (SCN, the site of the mammalian circadian (daily pacemaker, contains thousands of interconnected neurons, some of which receive direct retinal input. Here, we study the fast (<1 s responses of SCN neurons to visual stimuli with a large-scale mathematical model tracking the ionic currents and voltage of all SCN neurons. We reconstruct the SCN network connectivity and reject 99.99% of theoretically possible SCN networks by requiring that the model reproduces experimentally determined receptive fields of SCN neurons. The model shows how the SCN neuronal network can enhance circadian entrainment by sensitizing a population of neurons in the ventral SCN to irradiance. This SCN network also increases the spatial acuity of neurons and increases the accuracy of a simulated subconscious spatial visual task. We hypothesize that much of the fast electrical activity within the SCN is related to the processing of spatial information.

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

    Science.gov (United States)

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

    2012-01-01

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

  20. [Bioinorganic chemical composition of the lens and methods of its investigation].

    Science.gov (United States)

    Avetisov, S E; Novikov, I A; Pakhomova, N A; Motalov, V G

    2018-01-01

    Bioinorganic chemical composition of the lens of human and experimental animals (cows, dogs, rats, rabbits) have been analyzed in various studies. In most cases, the studies employed different methods to determine the gross (total) composition of chemical elements and their concentrations in the examined samples. Less frequently, they included an assessment of the distribution of chemical elements in the lens and correlation of their concentration with its morphological changes. Chemical elements from all groups (series) of the periodic classification system were discovered in the lens substance. Despite similar investigation methods, different authors obtained contradicting results on the chemical composition of the lens. This article presents data suggesting possible correlation between inorganic chemical elements in the lens substance with the development and formation of lenticular opacities. All currently employed methods are known to only analyze limited number of select chemical elements in the tissues and do not consider the whole range of elements that can be analyzed with existing technology; furthermore, the majority of studies are conducted on the animal model lens. Therefore, it is feasible to continue the development of the chemical microanalysis method by increasing the sensitivity of Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) with the purpose of assessing the gross chemical composition and distribution of the elements in the lens substance, as well as revealing possible correlation between element concentration and morphological changes in the lens.

  1. The Effect of the Crystalline Lens on Central Vault After Implantable Collamer Lens Implantation.

    Science.gov (United States)

    Qi, Meng-Ying; Chen, Qian; Zeng, Qing-Yan

    2017-08-01

    To identify associations between crystalline lens-related factors and central vault after Implantable Collamer Lens (ICL) (Staar Surgical, Monrovia, CA) implantation. This retrospective clinical study included 320 eyes from 186 patients who underwent ICL implantation surgery. At 1 year after surgery, the central vault was measured using anterior segment optical coherence tomography. Preoperative anterior chamber depth, lens thickness, lens position (lens position = anterior chamber depth + 1/2 lens thickness), and vault were analyzed to investigate the effects of lens-related factors on postoperative vault. The mean vault was 513 ± 215 µm at 1 year after surgery. Vault was positively correlated with preoperative anterior chamber depth (r = 0.495, P lens position (r = 0.371, P lens thickness (r = -0.262, P lens position than eyes in the other two vault groups (which had vaults ≥ 250 µm) (P lens position less than 5.1 mm had greatly reduced vaults (P lens could have an important influence on postoperative vault. Eyes with a shallower anterior chamber and a forward lens position will have lower vaults. [J Refract Surg. 2017;33(8):519-523.]. Copyright 2017, SLACK Incorporated.

  2. Constituent quark mass and nucleon properties in nuclei

    International Nuclear Information System (INIS)

    Beyer, M.; Singh, S.K.

    1986-01-01

    It is shown that the Nolen-Schiffer anomaly, the quenching of gsub(A) and the increase in some electromagnetic properties of nucleons in nuclei can all be explained qualitatively in a constituent quark model if the quark mass is assumed to depend on its confinement size. (author)

  3. Model for pairing phase transition in atomic nuclei

    International Nuclear Information System (INIS)

    Schiller, A.; Guttormsen, M.; Hjorth-Jensen, M.; Rekstad, J.; Siem, S.

    2002-01-01

    A model is developed which allows the investigation and classification of the pairing phase transition in atomic nuclei. The regions of the parameter space are discussed for which a pairing phase transition can be observed. The model parameters include number of particles, attenuation of pairing correlations with increasing seniority, single-particle level spacing, and pairing gap parameter

  4. Isospin mixing in light nuclei

    International Nuclear Information System (INIS)

    Ludwig, E.J.; Clegg, T.B.; Fauber, R.E.; Karwowski, H.J.; Mooney, T.M.; Thompson, W.J.

    1985-01-01

    This program has provided accurate measurements of isospin mixing (ΔT = 1,2) in proton elastic scattering on even-even target nuclei up to A = 40. In order to improve experimental results and to test the hypothesis that isospin mixing is dominated by mixing in the target ground state (as opposed to mixing in the compound system) the authors have undertaken to (1) extend the proton scattering results to additional T = 3/2 states in certain compound systems and (2) examine processes which can proceed by only isotensor mixing (ΔT = 2) in order to isolate the effects of that contribution

  5. Nucleon transfer between heavy nuclei

    International Nuclear Information System (INIS)

    Von Oertzen, W.

    1984-02-01

    Nucleon transfer reactions between heavy nuclei are characterized by the classical behaviour of the scattering orbits. Thus semiclassical concepts are well suited for the description of these reactions. In the present contribution the characteristics of single and multinucleon transfer reactions at energies below and above the Coulomb barrier are shown for systems like Sn+Sn, Xe+U and Ni+Pb. The role of the pairing interaction in the transfer of nucleon pairs is illustrated. For strong transitions the coupling of channels and the absorption into more complicated channels is taken into account in a coupled channels calculation

  6. Microscopic structure for light nuclei

    International Nuclear Information System (INIS)

    Sharma, V.K.

    1995-01-01

    The microscopic structure for light nuclei e.g. 4 He, 7 Li and 8 Be is considered in the frame work of the generator coordinate method (GCM). The physical interpretation of our GCM is also discussed. The GC amplitudes are used to calculate the various properties like charge and magnetic RMS radii, form factors, electromagnetic moments, astrophysical S-factor, Bremsstrahlung weighted cross sections, relative wavefunctions and vertex functions etc. All the calculated quantities agree well with the values determined experimentally. (author). 30 refs., 10 figs., 2 tabs

  7. Microscopic properties of superdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Lennart B

    1999-04-01

    Many high spin rotational bands in superdeformed nuclei have been found in the A 140 - 150 region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed states. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy. Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential. In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the E{sub {gamma}} and J{sup (2)} distributions. The importance of high-N orbitals for identical bands is also discussed. Additivity of electric quadrupole moment contributions in the superdeformed A - 150 region is discussed with the nucleus {sup 152}Dy as a `core`. In analytic harmonic oscillator calculations, the effective electric quadrupole moment q{sub eff}, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass, quadrupole moment q{sub {nu}}. Also in realistic calculations, simple relations between q{sub eff} and q{sub {nu}} can be used to estimate the total electric quadrupole moment, e.g. for the nucleus {sup 142}Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of {sup 152}Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed A - 150 region. For the superdeformed region around {sup 143}Eu, configuration and spin assignments

  8. Exclusive description of multiple production on nuclei in the additive quark model. Multiplicity distributions in interactions with heavy nuclei

    International Nuclear Information System (INIS)

    Levchenko, B.B.; Nikolaev, N.N.

    1985-01-01

    In the framework of the additive quark model of multiple production on nuclei we calculate the multiplicity distributions of secondary particles and the correlations between secondary particles in πA and pA interactions with heavy nuclei. We show that intranuclear cascades are responsible for up to 50% of the nuclear increase of the multiplicity of fast particles. We analyze the sensitivity of the multiplicities and their correlations to the choice of the quark-hadronization function. We show that with good accuracy the yield of relativistic secondary particles from heavy and intermediate nuclei depends only on the number N/sub p/ of protons knocked out of the nucleus, and not on the mass number of the nucleus (N/sub p/ scaling)

  9. [Magnetic resonance imaging study of effects of accommodation on human lens morphological characters].

    Science.gov (United States)

    Zheng, Sui-lian; Zhang, Ai; Shi, Jian-jing; Zhou, Yun-xin

    2013-11-05

    To evaluate the effects of accommodation on lens morphological characters. From January 2011 to June 2011, magnetic resonance images of eyes were acquired from 30 subjects aged 20 to 24 years during accommodation and at rest. The optimal images were analyzed by Autocad 2010 to obtain the total lens cross-sectional area (CSA) and CSA of anterior and posterior portions of lens, anterior chamber depth, lens thickness, lens diameter, vitreous chamber depth and axial length during accommodation and at rest. Paired-t test was performed. The anterior curvature radius (mm), posterior curvature radius (mm), CSA of anterior portion (mm(2)), CSA of posterior portion (mm(2)), total lens CSA (mm(2)) was (8.7 ± 0.8), (6.2 ± 0.5), (7.5 ± 2.1), (12.0 ± 2.6), (20 ± 4) during relaxed accommodation; anterior curvature radius (mm), posterior curvature radius (mm), CSA of anterior portion (mm(2)), CSA of posterior portion (mm(2)), total lens CSA (mm(2)) was (7.1 ± 1.3), (5.6 ± 0.5), (14.7 ± 2.9), (12.2 ± 2.1) and (27 ± 4) during accommodation. The total lens CSA (t = -11.556, P 0.05) under a statistically independent accommodative state. There was significant difference in the anterior chamber depth (t = 4.366, P 0.05) and axial length (t = 0.418, P > 0.05) under accommodative states. During accommodation, the anterior chamber depth decreases, lens thickness increases and diameter of lens decreases while anterior portions and total lens CSA increase. There are insignificant changes in posterior portions of lens CSA, vitreous chamber depth and axial length. The accommodative changes in CSA indicate that the anterior portion of lens may be related with the properties of anterior capsule and lens material, the position of zonular attachments and the location of fetal nucleus. Helmholtz theory is supported.

  10. Exotic nuclei: another aspect of nuclear structure

    International Nuclear Information System (INIS)

    Dobaczewski, J.; Blumenfeld, Y.; Flocard, H.; Garcia Borge, M.J.; Nowacki, F.; Rombouts, S.; Theisen, Ch.; Marques, F.M.; Lacroix, D.; Dessagne, P.; Gaeggeler, H.

    2002-01-01

    This document gathers the lectures made at the Joliot Curie international summer school in 2002 whose theme that year was exotic nuclei. There were 11 contributions whose titles are: 1) interactions, symmetry breaking and effective fields from quarks to nuclei; 2) status and perspectives for the study of exotic nuclei: experimental aspects; 3) the pairing interaction and the N = Z nuclei; 4) borders of stability region and exotic decays; 5) shell structure of nuclei: from stability to decay; 6) variational approach of system with a few nucleons; 7) from heavy to super-heavy nuclei; 8) halos, molecules and multi-neutrons; 9) macroscopic approaches for fusion reactions; 10) beta decay: a tool for spectroscopy; 11) the gas phase chemistry of super-heavy elements

  11. On the distribution of quarks in nuclei

    International Nuclear Information System (INIS)

    Baldin, A.M.; Panebrattsev, V.S.; Stavinskij, V.S.

    1984-01-01

    On the basis of the data on cumulative proton, deuteron and nuclear fragment production in hadr on-nucleon reactions and deep inelastic muon-nucleon scattering quark distributions in light, intemediate and heavy nuclei have been investigated. Conditions of limiting fragmentation of hadrons and nuclei in the studied processes have been investigated to obtain quark-parton structure functions (Gs 2 ) of the studied hadrons or nuclei. Invariant differential cross sections of π + , π - , K + meson production on aluminium, deuterium and lead nuclei and their dependence on scale variable at the transverse momentum value Psub(T) approximately 0 have been obtained. Properties of structure functions G 2 and behaviour of different nuclei differential cross sections of limiting fragmentation have been investigated. It is concluded that considered regularities testify to the presence of multiquark states in nuclei, different by its structure from nUcleons

  12. Subnanosecond lifetime measurements of excited states in nuclei far from stability

    International Nuclear Information System (INIS)

    Nettles, W.G.; Ramayya, A.V.; Hamilton, J.H.; Avignone, F.T. III; Carter, H.K.

    1979-01-01

    A system was developed to measure the lifetimes of nuclear states in the range of 0.05 to 1 nanosecond in nuclei far from stability. A Gerholm magnetic lens was placed on-line with the UNISOR mass separator to observe conversion electrons in coincidence with γ rays detected in a plastic scintillator. With this system, the half-life of the 522 keV, O + level in 186 Hg was measured to be 155 +- 70 picoseconds. Improvements in this system should make possible on-line measurements of half-lives as short as approx. = 50 picoseconds. 12 references

  13. Subnanosecond lifetime measurements of excited states in nuclei far from stability

    International Nuclear Information System (INIS)

    Nettles, W.G.; Ramayya, A.V.; Hamilton, J.H.; Avignone, F.T. III; Carter, H.K.

    1980-01-01

    A system has been developed to measure the lifetimes of nuclear states in the range of 0.05 to 1 nanosecond in nuclei far from stability. A Gerholm magnetic lens was placed on-line with the UNISOR mass separator to observe conversion electrons in coincidence with γ rays detected in a plastic scintillator. With this system, the half-life of the 522 keV, 0 + level in 186 Hg was measured to be 155 +- 70 picoseconds. Improvements in this system should make possible on-line measurements of half-lives as short as approximately 50 picoseconds. (Auth.)

  14. Laser method of free atom nuclei orientation

    International Nuclear Information System (INIS)

    Barabanov, A.L.

    1987-01-01

    Orientation process of free atom (atoms in beams) nuclei, scattering quanta of circularly polarized laser radiation is considered. A method for the evaluation of nuclei orientation parameters is developed. It is shown that in the process of pumping between the ground and first excited atomic states with electron shell spins J 1 and J 2 , so that J 2 = J 1 + 1, a complete orientation of nuclei can be attained

  15. Are there multiquark bags in nuclei

    International Nuclear Information System (INIS)

    Kondratyuk, L.A.; Scmatkov, M.Zh.

    1983-01-01

    Arguments are presented favouring the idea that multiquark bags do eXist in nuclei. Such hypothesis makes possible to reveal the relationship among three different scopes of phenomena: deep inelastic scattering of leptons by nUclei, large q 2 (where q 2 is a square of momentum transfer) behaviour of the form factors of light nuclei and yield of cumulative proton.s

  16. Understanding Nuclei in the upper sd - shell

    OpenAIRE

    Sarkar, M. Saha; Bisoi, Abhijit; Ray, Sudatta; Kshetri, Ritesh; Sarkar, S.

    2013-01-01

    Nuclei in the upper-$sd$ shell usually exhibit characteristics of spherical single particle excitations. In the recent years, employment of sophisticated techniques of gamma spectroscopy has led to observation of high spin states of several nuclei near A$\\simeq$ 40. In a few of them multiparticle, multihole rotational states coexist with states of single particle nature. We have studied a few nuclei in this mass region experimentally, using various campaigns of the Indian National Gamma Array...

  17. Possible existence of backbending in actinide nuclei

    International Nuclear Information System (INIS)

    Dudek, J.; Nazarewicz, W.; Szymanski, Z.

    1982-01-01

    The possibilities for the backbending effect to occur in actinide nuclei are studied using the pairing-self-consistent independent quasiparticle method. The Hamiltonian used is that of the deformed Woods-Saxon potential plus monopole pairing term. The results of the calculations explain why there is no backbending in most actinide nuclei and simultaneously suggest that in some light neutron deficient nuclei around Th and 22 Ra a backbending effect may occur

  18. Nuclei quadrupole coupling constants in diatomic molecule

    International Nuclear Information System (INIS)

    Ivanov, A.I.; Rebane, T.K.

    1993-01-01

    An approximate relationship between the constants of quadrupole interaction of nuclei in a two-atom molecule is found. It enabled to establish proportionality of oscillatory-rotation corrections to these constants for both nuclei in the molecule. Similar results were obtained for the factors of electrical dipole-quadrupole screening of nuclei. Applicability of these relationships is proven by the example of lithium deuteride molecule. 4 refs., 1 tab

  19. Nuclei at the limits of particle stability

    International Nuclear Information System (INIS)

    Mueller, A.C.

    1993-01-01

    The properties and synthesis of nuclei at the limits of particle stability are reviewed. Nuclear reactions were induced and studied by means of the 'exotic' nuclear beams, i.e. beams of radioactive drip-line nuclei. The beams are mostly generated in heavy-ion projectile fragmentation. The cases of both neutron-rich and proton-rich nuclei are discussed. (K.A.) 270 refs.; 13 figs.; 1 tab

  20. Primary intraocular lens implantation for penetrating lens trauma in Africa.

    Science.gov (United States)

    Bowman, R J; Yorston, D; Wood, M; Gilbert, C; Foster, A

    1998-09-01

    This study aimed to audit the surgical strategy of primary posterior chamber intraocular lens implantation for cases of recent penetrating trauma involving the lens in an African population. Retrospective, noncomparative case series. Seventy-two cases are reported, including all patients who underwent primary intraocular lens implantation for traumatic cataract extraction performed within 1 month of injury between 1988 and 1996. Demographic characteristics and follow-up attendance rates are analyzed. Surgical technique and the occurrence of intraoperative and postoperative complications are reported. Visual outcomes are reported with detailed analysis for cases of poor visual outcome. Mean age was 14.3 years (standard deviation = 11.1), 57 (79%) were male and 15 (21%) were female (chi-square = 23.66, P capsule had been breached by the trauma in 27 (38%) cases, and 15 of these required anterior vitrectomy. Capsular fixation of the implant was achieved in 49% of patients, the remainder having sulcus fixation. Intraoperative rupture of the posterior capsule occurred in four cases. The only common postoperative complication was acute fibrinous anterior uveitis, which occurred in 29 (40%) patients, and 32% of patients followed up for at least 6 months required secondary posterior capsulotomy. This was more common in younger patients (chi-square = 4.2, P < 0.05). Corrected postoperative visual acuities were available for 51 patients, of which 71% achieved 20/60 or better visual acuity. Patients 6 years of age or younger were less likely to achieve 20/60 (chi-square = 6.61, P = 0.01). This surgical strategy has proved successful, producing good visual results and causing no sight-threatening complications. Primary posterior capsulotomy may be appropriate for younger patients.

  1. DISSECTING THE GRAVITATIONAL LENS B1608+656. I. LENS POTENTIAL RECONSTRUCTION

    NARCIS (Netherlands)

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

    2009-01-01

    Strong gravitational lensing is a powerful technique for probing galaxy mass distributions and for measuring cosmological parameters. Lens systems with extended source-intensity distributions are particularly useful for this purpose since they provide additional constraints on the lens potential (

  2. Selfconsistent calculations for hyperdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Molique, H.; Dobaczewski, J.; Dudek, J.; Luo, W.D. [Universite Louis Pasteur, Strasbourg (France)

    1996-12-31

    Properties of the hyperdeformed nuclei in the A {approximately} 170 mass range are re-examined using the self-consistent Hartree-Fock method with the SOP parametrization. A comparison with the previous predictions that were based on a non-selfconsistent approach is made. The existence of the {open_quotes}hyper-deformed shell closures{close_quotes} at the proton and neutron numbers Z=70 and N=100 and their very weak dependence on the rotational frequency is suggested; the corresponding single-particle energy gaps are predicted to play a role similar to that of the Z=66 and N=86 gaps in the super-deformed nuclei of the A {approximately} 150 mass range. Selfconsistent calculations suggest also that the A {approximately} 170 hyperdeformed structures have neglegible mass asymmetry in their shapes. Very importantly for the experimental studies, both the fission barriers and the {open_quotes}inner{close_quotes} barriers (that separate the hyperdeformed structures from those with smaller deformations) are predicted to be relatively high, up to the factor of {approximately}2 higher than the corresponding ones in the {sup 152}Dy superdeformed nucleus used as a reference.

  3. Mass-23 nuclei in astrophysics

    International Nuclear Information System (INIS)

    Fraser, P R; Amos, K; Van der Kniff, D; Canton, L; Karataglidis, S; Svenne, J P

    2015-01-01

    The formation of mass-23 nuclei by radiative capture is of great interest in astrophysics. A topical problem associated with these isobars is the so-called 22 Na puzzle of ONe white dwarf novae, where the abundance of 22 Na observed is not as is predicted by current stellar models, indicating there is more to learn about how the distribution of elements in the universe occurred. Another concerns unexplained variations in elements abundance on the surface of aging red giant stars. One method for theoretically studying nuclear scattering is the Multi-Channel Algebraic Scattering (MCAS) formalism. Studies to date have used a simple collective-rotor prescription to model the target states which couple to projectile nucleons. While, in general, the target states considered all belong to the ground state rotor band, for some systems it is necessary to include coupling to states outside of this band. Herein we discuss an extension of MCAS to allow coupling of different strengths between such states and the ground state band. This consideration is essential when studying the scattering of neutrons from 22 Ne, a necessary step in studying the mass-23 nuclei mentioned above. (paper)

  4. Metallic plates lens focalizing a high power microwave beam

    International Nuclear Information System (INIS)

    Rebuffi, L.

    1987-08-01

    A metallic grating composed of thin parallel plates opportunely spaced, permits to correct the phase of an incident high power microwave beam. In this work we show how it is possible to obtain a beam focalisation (lens), a beam deflection (prisma), or a variation in the polarization (polarizer) using parallel metallic plates. The main design parameters are here presented, in order to obtain the wanted phase modification keeping low the diffraction, the reflected power, the ohmic losses and avoiding breakdowns. Following the given criteria, a metallic plate lens has been realized to focalize the 200 KW, 100 msec 60 GHz beam used in the ECRH experiment on the TFR tokamak. The experimental beam concentration followed satisfactory the design requirements. In fact, the maximum intensity increased about twice the value without lens. In correspondence of this distance a reduction of the beam size of about 50% have been measured for the -3 dB radius. The lens supported high power tests without breakdowns or increase of the reflected power

  5. Deep inelastic collisions between very heavy nuclei

    International Nuclear Information System (INIS)

    Sann, H.; Olmi, A.; Civelekoglu, Y.

    1977-01-01

    A systematic survey of deep inelastic reactions was performed for colliding nuclei of masses between 80 and 240 amu. The application of large surface detectors and, particularly, of a position sensitive ionization chamber, has proved to be very effective and appropriate for this type of investigation. The Wilczynski diagrams describing the relative motion between the colliding objects shows a gradual trend as a function of growing masses of target and projectile where the trajectories lead the particles not toward negative scattering angles but increasingly into the direction around and above the grazing angle. This behavior is attributed to a delicate balance between Coulomb and nuclear forces. The energy dumping as a function of the mass transfer strength matches a general law between total kinetic energy loss and the variance of the proton number distribution. For the partly damped component this relation seems to hold independently from the choice of ingoing channel and bombarding energy. The dissipation of the kinetic energy does not depend only on the relative velocity of the impinging nuclei, and the simple friction model is not appropriate to describe these processes. The γ-multiplicity measurement displays a rapid increase as a function of scattering angle and total kinetic energy loss, which give new insights to the process and indicate the necessity of microscopic quantum mechanical calculations of the interaction. In the U-U collision large mass transfers are present which possibly populate with relatively large cross sections the transuranic elements. In the Pb-Pb reaction the mass transfer is more restricted. The decay probability by fission of the primary masses increases strongly for growing masses and excitation energies

  6. Robust nuclei segmentation in cyto-histopathological images using statistical level set approach with topology preserving constraint

    Science.gov (United States)

    Taheri, Shaghayegh; Fevens, Thomas; Bui, Tien D.

    2017-02-01

    Computerized assessments for diagnosis or malignancy grading of cyto-histopathological specimens have drawn increased attention in the field of digital pathology. Automatic segmentation of cell nuclei is a fundamental step in such automated systems. Despite considerable research, nuclei segmentation is still a challenging task due noise, nonuniform illumination, and most importantly, in 2D projection images, overlapping and touching nuclei. In most published approaches, nuclei refinement is a post-processing step after segmentation, which usually refers to the task of detaching the aggregated nuclei or merging the over-segmented nuclei. In this work, we present a novel segmentation technique which effectively addresses the problem of individually segmenting touching or overlapping cell nuclei during the segmentation process. The proposed framework is a region-based segmentation method, which consists of three major modules: i) the image is passed through a color deconvolution step to extract the desired stains; ii) then the generalized fast radial symmetry transform is applied to the image followed by non-maxima suppression to specify the initial seed points for nuclei, and their corresponding GFRS ellipses which are interpreted as the initial nuclei borders for segmentation; iii) finally, these nuclei border initial curves are evolved through the use of a statistical level-set approach along with topology preserving criteria for segmentation and separation of nuclei at the same time. The proposed method is evaluated using Hematoxylin and Eosin, and fluorescent stained images, performing qualitative and quantitative analysis, showing that the method outperforms thresholding and watershed segmentation approaches.

  7. Algorithm design of liquid lens inspection system

    Science.gov (United States)

    Hsieh, Lu-Lin; Wang, Chun-Chieh

    2008-08-01

    In mobile lens domain, the glass lens is often to be applied in high-resolution requirement situation; but the glass zoom lens needs to be collocated with movable machinery and voice-coil motor, which usually arises some space limits in minimum design. In high level molding component technology development, the appearance of liquid lens has become the focus of mobile phone and digital camera companies. The liquid lens sets with solid optical lens and driving circuit has replaced the original components. As a result, the volume requirement is decreased to merely 50% of the original design. Besides, with the high focus adjusting speed, low energy requirement, high durability, and low-cost manufacturing process, the liquid lens shows advantages in the competitive market. In the past, authors only need to inspect the scrape defect made by external force for the glass lens. As to the liquid lens, authors need to inspect the state of four different structural layers due to the different design and structure. In this paper, authors apply machine vision and digital image processing technology to administer inspections in the particular layer according to the needs of users. According to our experiment results, the algorithm proposed can automatically delete non-focus background, extract the region of interest, find out and analyze the defects efficiently in the particular layer. In the future, authors will combine the algorithm of the system with automatic-focus technology to implement the inside inspection based on the product inspective demands.

  8. Freeform lens design for LED collimating illumination.

    Science.gov (United States)

    Chen, Jin-Jia; Wang, Te-Yuan; Huang, Kuang-Lung; Liu, Te-Shu; Tsai, Ming-Da; Lin, Chin-Tang

    2012-05-07

    We present a simple freeform lens design method for an application to LED collimating illumination. The method is derived from a basic geometric-optics analysis and construction approach. By using this method, a highly collimating lens with LED chip size of 1.0 mm × 1.0 mm and optical simulation efficiency of 86.5% under a view angle of ± 5 deg is constructed. To verify the practical performance of the lens, a prototype of the collimator lens is also made, and an optical efficiency of 90.3% with a beam angle of 4.75 deg is measured.

  9. Ascorbic acid glycation of lens proteins produces UVA sensitizers similar to those in human lens

    International Nuclear Information System (INIS)

    Ortwerth, B.J.; Linetsky, Mikhail; Olesen, P.R.

    1995-01-01

    Soluble calf lens proteins were extensively glycated during a 4 week incubation with ascorbic acid in the presence of oxygen. Amino acids analysis of the dialyzed proteins removed at weekly intervals showed an increasing loss of lysine, arginine and histidine, consistent with the extensive protein cross-linking observed. Irradiation of the dialyzed samples with UVA light (1.0 kJ/cm 2 total illumination through a 338 nm cutoff filter) caused an increasing loss of tryptophan, an additional loss of histidine and the production of micromolar concentrations of hydrogen peroxide. No alteration in amino acid content and no photolytic effects were seen in proteins incubated without ascorbic acid in proteins incubated with glucose for 4 weeks. The rate of hydrogen peroxide formation was linear with each glycated sample with a maximum production of 25 nmol/mg protein illuminated. The possibility that the sensitizer activity was due to an ascorbate-induced oxidation of tryptophan was eliminated by the presence of a heavy metal ion chelator during the incubation and by showing equivalent effects with ascorbate-incubated ribonuclease A, which is devoid of tryptophan. The ascorbate-incubated samples displayed increasing absorbance at wavelengths above 300 nm and increasing fluorescence (340/430) as glycation proceeded. The spectra of the 4 week glycated proteins were identical to those obtained with a solubilized water-insoluble fraction from human lens, which is known to have UVA sensitizer activity. (Author)

  10. Changes in lens stiffness due to capsular opacification in accommodative lens refilling

    NARCIS (Netherlands)

    Nibourg, Lisanne M.; Sharma, Prashant K.; van Kooten, Theo G.; Koopmans, Steven A.

    Accommodation may be restored to presbyopic lenses by refilling the lens capsular bag with a soft polymer. After this accommodative lens refilling prevention of capsular opacification is a requirement, since capsular opacification leads to a decreased clarity of the refilled lens. It has been

  11. Exchange of tears under a contact lens is driven by distortions of the contact lens.

    Science.gov (United States)

    Maki, Kara L; Ross, David S

    2014-12-01

    We studied the flow of the post-lens tear film under a soft contact lens to understand how the design parameters of contact lenses can affect ocular health. When a soft contact lens is inserted, the blinking eyelid causes the lens to stretch in order to conform to the shape of the eye. The deformed contact lens acts to assume its un-deformed shape and thus generates a suction pressure in the post-lens tear film. In consequence, the post-lens tear fluid moves; it responds to the suction pressure. The suction pressure may draw in fresh fluid from the edge of the lens, or it may eject fluid there, as the lens reassumes its un-deformed shape. In this article, we develop a mathematical model of the flow of the post-lens tear fluid in response to the mechanical suction pressure of a deformed contact lens. We predict the amount of exchange of fluid exchange under a contact lens and we explore the influence of the eye's shape on the rate of exchange of fluid. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  12. Real and virtual pions in nuclei

    International Nuclear Information System (INIS)

    Giraud, N.

    1984-02-01

    The thesis first part is concerned with physical pion interaction with deuton, studied in a three-body problem frame. The elastic cross-section in the energy range near the resonance (3-3), has been deduced taking in account the pion virtual absorption. The second part is concerned with virtual pion in nuclei. In particular the virtual pion cloud around the nucleus has been studied and the effective constant coupling pion-nucleus has been deduced. This one is strongly reduced by polorazation effects of the nuclear medium (essentially by virtual excitation of the Δ isobar), in relation to its value for free nucleon collection. In the frame of the same polarization model, the pion field inside the nucleus has been studied also. This field is lowered for small momentum transfer. It is increased for large momentum transfer. This last phenomenon corresponds to critical opalescence related to phase transition of pion condensation [fr

  13. Pseudomonas aeruginosa Survival at Posterior Contact Lens Surfaces after Daily Wear

    Science.gov (United States)

    Wu, Yvonne T.; Zhu, Lucia S.; Tam, K. P. Connie; Evans, David J.; Fleiszig, Suzanne M. J.

    2015-01-01

    Purpose Pseudomonas aeruginosa keratitis is a sight-threatening complication of contact lens wear, yet mechanisms by which lenses predispose to infection remain unclear. Here, we tested the hypothesis that tear fluid at the posterior contact lens surface can lose antimicrobial activity over time during lens wear. Methods Daily disposable lenses were worn for 1, 2, 4, 6 or 8 h immediately after removal from their packaging, or after presoaking in sterile saline for 2 days to remove packaging solution. Unworn lenses were also tested, some coated in tears “aged” in vitro for 1 or 8 h. Lenses were placed anterior surface down into tryptic soy agar cradles containing gentamicin (100µg/ml) to kill bacteria already on the lens, and posterior surfaces inoculated with gentamicin-resistant P. aeruginosa for 3 h. Surviving bacteria were enumerated by viable counts of lens homogenates. Results Posterior surfaces of lenses worn by patients for 8 h supported more P. aeruginosa growth than lenses worn for only 1 h, if lenses were presoaked prior to wear (~ 2.4-fold, p = 0.01). This increase was offset if lenses were not presoaked to remove packaging solution (p = 0.04 at 2 h and 4 h). Irrespective of presoaking, lenses worn for 8 h showed more growth on their posterior surface than unworn lenses coated with tear fluid that was “aged” for 8 h vitro (~8.6-fold, presoaked, p = 0.003: ~ 5.4-fold from packaging solution, p = 0.004). Indeed, in vitro incubation did not impact tear antimicrobial activity. Conclusions This study shows that post lens tear fluid can lose antimicrobial activity over time during contact lens wear, supporting the idea that efficient tear exchange under a lens is critical for homeostasis. Additional studies are needed to determine applicability to other lens types, wearing modalities, and relevance to contact lens-related infections. PMID:25955639

  14. The asymptotic hadron spectrum, anti-nuclei, hyper-nuclei and quark phase

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1978-01-01

    The only hope of determining the hadronic spectrum in the high mass region is through a study of matter produced in very high energy nuclear collisions. Along the way, exotic nuclei, i.e., anti-nuclei and hyper-nuclei may be produced in appreciable numbers, and the detection of a quark phase may be possible. (orig.) [de

  15. Gamow-Teller decay of T = 1 nuclei to odd-odd N = Z nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Lisetskiy, A F [National Superconducting Cyclotron Laboratory, MSU, East Lansing, MI 48824 (United States); Gelberg, A [Institute for Nuclear Physics, University of Cologne, 50937 Cologne (Germany); Institute of Physical and Chemical Reasearch (RIKEN), Wako, 351-0198 (Japan); Brentano, P von [Institute for Nuclear Physics, University of Cologne, 50937 Cologne (Germany)

    2005-01-01

    Transition strengths of Gamow-Teller decay of T{sub z} = {+-}1 nuclei to N = Z odd-odd nuclei have been calculated in a two-nucleon approximation for spherical and deformed nuclei. The results obtained for the latter are quite close to the values obtained by full-space shell-model calculations and to the experiment.

  16. Pigment deposition on the central aspect of the posterior lens capsule in pigmentary dispersion.

    Science.gov (United States)

    Nagarajaiah, Shubha; Shun-Shin, Georges Adrien

    2011-01-01

    We describe a case of an increasing pigmentary plaque on the posterior surface of the lens during follow-up of a case of pigment dispersion syndrome and suggest that this is a new sign of pigment dispersion.

  17. Pigment deposition on the central aspect of the posterior lens capsule in pigmentary dispersion

    OpenAIRE

    Nagarajaiah, Shubha; Shun-Shin, Georges Adrien

    2011-01-01

    We describe a case of an increasing pigmentary plaque on the posterior surface of the lens during follow-up of a case of pigment dispersion syndrome and suggest that this is a new sign of pigment dispersion.

  18. Lens design and local minima

    International Nuclear Information System (INIS)

    Brixner, B.

    1981-01-01

    The widespread belief that local minima exist in the least squares lens-design error function is not confirmed by the Los Alamos Scientific Laboratory (LASL) optimization program. LASL finds the optimum-mimimum region, which is characterized by small parameter gradients of similar size, small performance improvement per iteration, and many designs that give similar performance. Local minima and unique prescriptions have not been found in many-parameter problems. The reason for these absences is that image errors caused by a change in one parameter can be compensated by changes in the remaining parameters. False local minima have been found, and four cases are discussed

  19. Nuclei in neutrino-degenerate dense matter, 1

    International Nuclear Information System (INIS)

    Ogasawara, Ryusuke; Sato, Katsuhiko

    1982-01-01

    The properties of nuclei in cold dense matter with strongly degenerate neutrinos are investigated with the aid of an extended Thomas-Fermi model of nuclei. The following results are obtained. 1) The proton number of nucleus increases with the increasing density of the matter and it becomes very huge compared with that of the cold catalyzed matter due to the decrease of the Coulomb energy caused by the effect of the lattice-Coulomb energy. 2) The matter densities at the neutron-drip points, where the chemical potentials of neutrons equal zero are obtained as a function of the number of leptons per nucleon Y sub(L), and it is found that nuclei coalesce before neutron drip when Y sub(L) is greater than about 0.4 for the case b.c.c. lattice. 3) Along the neutron-drip points, an infinite network of linked nuclei may be formed at the matter density rho sub(P) asymptotically equals 9 x 10 13 g cm - 3 , and the bubble-phase appears at the matter density rho sub(B) asymptotically equals 1.1 x 10 14 g cm - 3 . When the matter density becomes higher than rho sub(H) asymptotically equals 1.7 x 10 14 g cm - 3 , the bubbles melt into a homogeneous matter. (author)

  20. Objective automated quantification of fluorescence signal in histological sections of rat lens.

    Science.gov (United States)

    Talebizadeh, Nooshin; Hagström, Nanna Zhou; Yu, Zhaohua; Kronschläger, Martin; Söderberg, Per; Wählby, Carolina

    2017-08-01

    Visual quantification and classification of fluorescent signals is the gold standard in microscopy. The purpose of this study was to develop an automated method to delineate cells and to quantify expression of fluorescent signal of biomarkers in each nucleus and cytoplasm of lens epithelial cells in a histological section. A region of interest representing the lens epithelium was manually demarcated in each input image. Thereafter, individual cell nuclei within the region of interest were automatically delineated based on watershed segmentation and thresholding with an algorithm developed in Matlab™. Fluorescence signal was quantified within nuclei, cytoplasms and juxtaposed backgrounds. The classification of cells as labelled or not labelled was based on comparison of the fluorescence signal within cells with local background. The classification rule was thereafter optimized as compared with visual classification of a limited dataset. The performance of the automated classification was evaluated by asking 11 independent blinded observers to classify all cells (n = 395) in one lens image. Time consumed by the automatic algorithm and visual classification of cells was recorded. On an average, 77% of the cells were correctly classified as compared with the majority vote of the visual observers. The average agreement among visual observers was 83%. However, variation among visual observers was high, and agreement between two visual observers was as low as 71% in the worst case. Automated classification was on average 10 times faster than visual scoring. The presented method enables objective and fast detection of lens epithelial cells and quantification of expression of fluorescent signal with an accuracy comparable with the variability among visual observers. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

  1. Scientific performance assessments through a gender lens

    DEFF Research Database (Denmark)

    Nielsen, Mathias Wullum

    2018-01-01

    The focus on excellence and quality assurance in the academy has spawned a signifi cant increase in the use of bibliometric measures in performance assessments of individual researchers. This article investigates the organizational consequences of this development through a gender lens. Based...... scholars, evaluators using bibliometrics risk disadvantaging candidates diverging from the norm with implications for gender stratifi cation. Despite these potential biases, bibliometric measures come to function as technologies supporting a managerial narrative of the gender-blind organization....... They adhere to the prevailing ethos of the academic meritocracy by standardizing the criteria for organizational advancement and ensuring transparency and accountability in the selection process. While bibliometric tools in this sense may lead to the recruitment of scientists with a strong CV and track record...

  2. The retro-cut process: precision reshaping of magnetic quadrupole lens profiles to improve field strength

    International Nuclear Information System (INIS)

    Szymanski, Roland; Jamieson, David N.; Rout, Bibhudutta; Brenn, Ruediger

    2005-01-01

    In the evolution of magnetic quadrupole lens technology for nuclear microprobe systems, the pole profile has seen several improvements that have led to increases in the pole tip field for a given lens current. In a design dating from prior to 1994 the magnetic field strength was compromised by pole tip extensions that allowed significant flux leakage away from the central bore of the lens. There are many similar lenses in use world wide and they have a weaker focusing action compared to more modern designs which omit the pole tip extensions. We demonstrate that these pre-1994 lenses can have a new profile cut into the pole tip using a precision wire cutting machine that does not require the lens to be dismantled and does not compromise the purity of the lens field. We present the results of applying this process to lenses 1 and 4 in the antisymmetric quadruplet nuclear microprobe system at the University of Freiburg. The grid shadow method was used to show lens quality was not compromised by the process and we find that the lens field strength for a given current is increased by 15% when used to focus 2 MeV H + ions in the antisymmetric quadruplet

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

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

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

    International Nuclear Information System (INIS)

    Zhang, D.

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    2015-01-01

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

  7. Composite hadrons and relativistic nuclei

    International Nuclear Information System (INIS)

    Blankenbecler, R.

    1978-01-01

    Lectures are presented describing a model of hadronic scattering at large momentum transfer, either transverse or longitudinal. This model emphasizes in this regime the importance of forces involving the interchange of constituents of the hadrons, hence its name, the constituent interchange model CIM. The CIM is a rearrangement of standard perturbation theory to take into account the fact that the binding force is very strong in color singlet states (singlet dominance). The hard scattering expansion, incoherence problems, nuclear wave functions and counting rules, interaction between nuclei, pion and proton yields and form factors, structure functions and nonscaling, massive lepton pairs, hadrons at large transverse momentum, and quark-quark scattering are treated. 49 references

  8. Neutron halo in deformed nuclei

    International Nuclear Information System (INIS)

    Zhou Shangui; Meng Jie; Ring, P.; Zhao Enguang

    2010-01-01

    Halo phenomena in deformed nuclei are investigated within a deformed relativistic Hartree Bogoliubov (DRHB) theory. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Contributions of the halo, deformation effects, and large spatial extensions of these systems are described in a fully self-consistent way by the DRHB equations in a spherical Woods-Saxon basis with the proper asymptotic behavior at a large distance from the nuclear center. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nucleus 44 Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the occurrence of this decoupling effects are discussed.

  9. Order against chaos in nuclei

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1995-01-01

    Order and chaos and order-to-chaos transition are treated in terms of nuclear wave functions. A quasiparticle-phonon interaction is responsible for the fragmentation of one- and many-quasiparticle and phonon states and for the mixing of closely spaced states. Complete damping of one-quasiparticle states cannot be considered as a transition to chaos due to large many-quasiparticle or quasiparticle-phonon terms in their wave functions. An experimental investigation of the strength distribution of many-quasiparticle and quasiparticle-phonon states should uncover a new region of a regularity in nuclei at intermediate excitation energy. A chaotic behaviour of nuclear states can be shifted to higher excitation energies. ((orig.))

  10. Relativistic description of atomic nuclei

    International Nuclear Information System (INIS)

    Krutov, V.A.

    1985-01-01

    Papers on the relativistic description of nuclei are reviewed. The Brown and Rho ''small'' bag'' model is accepted for hardrons. Meson exchange potentials of the nucleon-nucleon interaction have been considered. Then the transition from a system of two interacting nucleons has been performed to the relativistic nucleus description as a multinucleon system on the basis of OBEP (one-boson exchange potential). The proboem of OPEP (one-pion-exchange potential) inclusion to a relativistic scheme is discussed. Simplicity of calculations and attractiveness of the Walecka model for specific computations and calculations was noted. The relativistic model of nucleons interacting through ''effective'' scalar and vector boson fields was used in the Walacka model for describing neutronaand nuclear mater matters

  11. Electric quadrupole strength in nuclei

    International Nuclear Information System (INIS)

    Kirson, M.W.

    1979-01-01

    Isoscalar electric quadrupole strength distributions in nuclei are surveyed, and it is concluded that the strength is shared, in most cases, roughly equally between low-lying transitions and the giant quadrupole state. The same is not true of the isovector case. A simple extension of the schematic model gives a remarkably successul description of the data, and emphasizes the vital importance of the coupling between high-lying and low-lying quadrupole modes. The standadrd simple representation of the giant quadrupole resonance as produced by operating on the nuclear ground state with the quadrupole transition operator is not applicable to the isoscalar case. It is suggested that giant resonances fall into broad classes of similar states, with considerable qualitative differences between the distinct classes. (author)

  12. Cavitation Nuclei: Experiments and Theory

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2009-01-01

    The Swedish astrophysicist and Nobel Prize winner Hannes Alfven said: Theories come and go - the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory...... becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer...... us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories - and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character....

  13. Femtometer toroidal structures in nuclei

    International Nuclear Information System (INIS)

    Forest, J.L.; Pandharipande, V.R.; Pieper, S.C.; Wiringa, R.B.; Schiavilla, R.; Arriaga, A.

    1996-01-01

    The two-nucleon density distributions in states with isospin T=0, spin S=1, and projection M S =0 and ±1 are studied in 2 H, 3,4 He, 6,7 Li, and 16 O. The equidensity surfaces for M S =0 distributions are found to be toroidal in shape, while those of M S =±1 have dumbbell shapes at large density. The dumbbell shapes are generated by rotating tori. The toroidal shapes indicate that the tensor correlations have near maximal strength at r 3 He, 4 He, and 6 Li. The toroidal distribution has a maximum-density diameter of ∼1 fm and a half-maximum density thickness of ∼0.9 fm. Many realistic models of nuclear forces predict these values, which are supported by the observed electromagnetic form factors of the deuteron, and also predicted by classical Skyrme effective Lagrangians, related to QCD in the limit of infinite colors. Due to the rather small size of this structure, it could have a revealing relation to certain aspects of QCD. Experiments to probe this structure and its effects in nuclei are suggested. Pair distribution functions in other T,S channels are also discussed; those in T,S=1,1 have anisotropies expected from one-pion-exchange interactions. The tensor correlations in T,S=0,1 states are found to deplete the number of T,S=1,0 pairs in nuclei and cause a reduction in nuclear binding energies via many-body effects. copyright 1996 The American Physical Society

  14. Quarks and mesons in nuclei

    International Nuclear Information System (INIS)

    Rho, M.

    1981-01-01

    Quantum chromodynamics is believed to be candidate theory for the strong interactions and contains as its ingredients spinor quark fields and vector gluons, none of which can perhaps be ever liberated and detected in laboratories. A nucleus consists of nucleons bound by nuclear force which are however separately observable and which seem to preserve their identities even under extreme conditions. An intriguing question is: when compressed to high densities or heated to high temperature, at what point does a nuclear matter cease to be describable in terms of nucleon and meson degrees of freedom, but become a plasma of quarks and gluons; and how does this transition occur. This is not an idle question. If quarks and gluons are never to be observed isolated, then it may be that at low energies (or at low densities) they are not the right variables to do physics with. Instead hadrons must be. On the other hand, asymptotic freedom - the unique property of non-abelian gauge theories to which QCD belongs that quark-gluon and gluon-gluon interactions get weaker at short distances - tells us that at some large matter density the matter must necessarily be in the form of quark gas interacting only weakly. This means that a change in degrees of freedom must take place. We would like to know where this occurs and how. In this talk, I would like to address to this question by discussing first the large success we have had in understanding the role that mesons play in finite nuclei and nuclear matter and then attempting to correlate nucleon and meson degrees of freedom to quark-gluon degrees of freedom. In my opinion we are now at a stage where we feel fairly confident in our understanding of nucleon-meson structure of nuclei and nuclear matter and any further progress in deeper understanding of nuclear dynamics - and strong interactions - must come from QCD or its effective version, bags or strings. (orig.)

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

    Science.gov (United States)

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

    2009-10-01

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

  16. Mean-field models and exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M; Buervenich, T; Maruhn, J A; Greiner, W [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); Rutz, K [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Reinhard, P G [Inst. fuer Theoretische Physik, Univ. Erlangen (Germany)

    1998-06-01

    We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)

  17. Microscopic Cluster Theory for Exotic Nuclei

    International Nuclear Information System (INIS)

    Tomaselli, M; Kuehl, T; Ursescu, D; Fritzsche, S

    2006-01-01

    For a better understanding of the dynamics of complex exotic nuclei it is of crucial importance to develop a practical microscopic theory easy to be applied to a wide range of masses. In this paper we propose to calculate the structure of neutron-rich nuclei within a dynamic model based on the EoM theory

  18. Reentrainment of radioactive nuclei from filters

    International Nuclear Information System (INIS)

    Dincklage, R.-D. von

    1982-01-01

    The possible relevance of atomic phenomena for the reentrainment of radioactive nuclei is discussed. The considerations are based on the coulombic fragmentation mechanism. Nuclei of potential interest in reprocessing technology are identified. Future experiments have been shown to be of definite need in this field. (author)

  19. Thermodynamics of pairing phase transition in nuclei

    International Nuclear Information System (INIS)

    Karim, Afaque; Ahmad, Shakeb

    2014-01-01

    The pairing gaps, pairing energy, heat capacity and entropy are calculated within BCS (Bardeen- Cooper-Schrieffer) based quasi particle approach, including thermal fluctuations on pairing field within pairing model for all nuclei (light, medium, heavy and super heavy nuclei). Quasi particles approach in BCS theory was introduced and reformulated to study various properties. For thermodynamic behavior of nuclei at finite temperatures, the anomalous averages of creation and annihilation operators are introduced. It is solved self consistently at finite temperatures to obtain BCS Hamiltonian. After doing unitary transformation, we obtained the Hamiltonian in the diagonal form. Thus, one gets temperature dependence gap parameter and pairing energy for nuclei. Moreover, the energy at finite temperatures is the sum of the condensation energy and the thermal energy of fermionic quasi particles. With the help of BCS Hamiltonian, specific heat, entropy and free energy are calculated for different nuclei. In this paper the gap parameter occupation number and pairing energy as a function of temperature which is important for all the light, medium, heavy and super heavy nuclei is calculated. Moreover, the various thermo dynamical quantities like specific heat, entropy and free energy is also obtained for different nuclei. Thus, the thermodynamics of pairing phase transition in nuclei is studied

  20. Mean-field models and exotic nuclei

    International Nuclear Information System (INIS)

    Bender, M.; Buervenich, T.; Maruhn, J.A.; Greiner, W.; Rutz, K.; Reinhard, P.G.

    1998-01-01

    We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)

  1. Static and dynamical properties of hot nuclei

    International Nuclear Information System (INIS)

    Suraud, E.

    1990-01-01

    We briefly review our understanding of the formation of excited/hot nuclei in heavy-ion collisions at some tens of MeV/A. We recall the major theoretical frameworks used for describing as well the entrance channel of the reaction as the structure properties of hot nuclei. We finally focus on multifragmentation within insisting upon the theoretical challenge it does represent

  2. Masses of nuclei close to the dripline

    International Nuclear Information System (INIS)

    Herfurth, F.; Blaum, K.; Audi, G.; Lunney, D.; Beck, D.; Kluge, H.J.; Rodriguez, D.; Sikler, G.; Weber, C.; Bollen, G.; Schwarz, S.; Kellerbauer, A.

    2003-01-01

    Mass measurements of radioactive nuclides are one of the cornerstones of our understanding of the nucleus. The Penning trap spectrometer ISOLTRAP performs direct mass measurements far away from the valley of stability, as well as high-precision measurements of key nuclei to anchor long decay chains. Both schemes provide valuable information on the dripline itself and on nuclei in its close vicinity. (orig.)

  3. Quasars, Seyfert galaxies and active galactic nuclei

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1987-01-01

    This chapter is devoted to the spectroscopic methods for analyzing the observed plasma in the nuclei of quasars, Seyfert galazies, and active galactic nuclei. Both the narrow-line region and the broad-line region are discussed. Physical models are presented

  4. Single Particle Entropy in Heated Nuclei

    International Nuclear Information System (INIS)

    Guttormsen, M.; Chankova, R.; Hjorth-Jensen, M.; Rekstad, J.; Siem, S.; Sunde, A. C.; Syed, N. U. H.; Agvaanluvsan, U.; Schiller, A.; Voinov, A.

    2006-01-01

    The thermal motion of single particles represents the largest contribution to level density (or entropy) in atomic nuclei. The concept of single particle entropy is presented and shown to be an approximate extensive (additive) quantity for mid-shell nuclei. A few applications of single particle entropy are demonstrated

  5. Quantum phase transitions in atomic nuclei

    International Nuclear Information System (INIS)

    Zamfir, N.V.

    2005-01-01

    Studies of quantum phase transitions in mesoscopic systems and applications to atomic nuclei are presented. Analysis in terms of the Interacting Boson Model shows that the main features persist even for moderate number of particles. Experimental evidence in rare-earth nuclei is discussed. New order and control parameters for systems with the same number of particles are proposed. (author)

  6. Interactions of 82Pb208 nuclei with energy 158 GeV per nucleon with photoemulsion nuclei

    International Nuclear Information System (INIS)

    Adamovich, M.I.; Andreeva, N.P.; Bubnov, V.I.; Gajtinov, A.Sh.; Kanygina, Eh.K.; Musaeva, A.K.; Sejtimbetov, A.M.; Skorobagatova, V.I.; Filippova, L.N.; Chasnikov, I.Ya.

    1999-01-01

    In this report there are experimental data on 82 Pb 208 nuclei (158 GeV) interaction with photoemulsion nuclei. The said data are compared to the similar ones for 79 Au 197 nuclei with less energy (10,7 A GeV). Stack of nuclear emulsion was irradiated with the beam of nuclei 82 Pb 208 at SPS of CERN. Events search was done along the primary nucleus trace. Pb nucleus average path length happened to be λ=(3,8±0,1) cm, this virtually coincides with the one calculated by Brandt and Peters formula (3,9 cm). Secondary particles were identified into s (storm), g (knock-on protons) and b- particles (target nucleus fragments), as well as into nucleus-bullet fragments with different charges (Z=1,2,≥3). This allowed obtaining event distribution by multiplicity of these particles (n s , n g , n b ) and fragments (n z=1,2,≥3 ), calculation of average values by multiplicity (see table), finding correlation of characteristics. >From the table it's clear that when the energy increases s > increases 2,5 times where as g > insignificantly decreases and b > doesn't change

  7. Superdeformed bands in Hg and Tl nuclei for N≤112

    International Nuclear Information System (INIS)

    Carpenter, M.P.; Jannsens, R.V.F.; Liang, Y.; Ahmad, I.; Henry, R.; Khoo, T.L.; Lauritsen, T.; Soramel, F.; Lewis, J.M.; Riedinger, L.L.; Yu, C.H.; Garg, U.; Reviol, W.; Pilotte, S.; Bearden, I.G.; Daly, P.J.

    1992-01-01

    The study of superdeformed (SD) nuclei in the A ∼ 190 region has provided a wealth of new information on SD states at moderate to high spins (I ∼ 10 to 50 h). The dynamical moment of inertia for almost all of the SD bands reported on to date in this mass region display a similar behavior, i.e. a smooth increase with increasing rotational frequency. This increase has been attributed to both quasiparticle alignments and a decrease in pairing with increasing rotational frequency. However, standard mean-field calculations have problems reproducing the magnitude and extent of the rise. The authors' recent results on SD states in the Hg-Tl nuclei at and below the N = 112 SD-gap add support to this interpretation of the rise in the dynamical moment of inertia while at the same time showing more clearly the inadequacies of the previous theoretical calculations

  8. Protection of the eye lens

    International Nuclear Information System (INIS)

    2015-01-01

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

  9. Variable wide range of lens power and its improvement in a liquid-crystal lens using highly resistive films divided into two regions with different diameters

    Science.gov (United States)

    Kawamura, Marenori; Sato, Susumu

    2018-05-01

    The variable range of lens power of a liquid-crystal (LC) lens driven by two voltages is discussed on the basis of calculated and experimental results. The LC lens has two electrodes, which are a circularly hole-patterned electrode and a circular electrode, in addition to a common electrode, and highly resistive transparent films. The variable range of lens power increases with increasing driving voltage applied across the circularly hole-patterned electrode and the common electrode, and with decreasing diameter of highly resistive films. However, the optical-phase retardation profile tends to deviate from a parabolic curve in these cases. As a method to improve the trade-off properties, the highly resistive film is divided into two regions with different diameters, where the sheet resistance of an outer film is larger than that of an inner one. The improved LC lens has a lens power that varies in a wide range, and it exhibits a good parabolic phase retardation profile.

  10. Optical fiber plasmonic lens for near-field focusing fabricated through focused ion beam

    Science.gov (United States)

    Sloyan, Karen; Melkonyan, Henrik; Moreira, Paulo; Dahlem, Marcus S.

    2017-02-01

    We report on numerical simulations and fabrication of an optical fiber plasmonic lens for near-field focusing applications. The plasmonic lens consists of an Archimedean spiral structure etched through a 100 nm-thick Au layer on the tip of a single-mode SM600 optical fiber operating at a wavelength of 632:8 nm. Three-dimensional finite-difference time-domain computations show that the relative electric field intensity of the focused spot increases 2:1 times when the number of turns increases from 2 to 12. Furthermore, a reduction of the intensity is observed when the initial inner radius is increased. The optimized plasmonic lens focuses light into a spot with a full-width at half-maximum of 182 nm, beyond the diffraction limit. The lens was fabricated by focused ion beam milling, with a 200nm slit width.

  11. Structure and clusters of light unstable nuclei

    International Nuclear Information System (INIS)

    En'yo, Yoshiko

    2010-01-01

    As it is known, cluster structures are often observed in light nuclei. In the recent evolution of unstable nuclear research (on nuclei having unbalanced number of neutron and proton) further new types of clusters are coming to be revealed. In this report, structures of light unstable nuclei and some of the theoretical models to describe them are reviewed. The following topics are picked up. 1. Cluster structure and theoretical models, 2. Cluster structure of unstable nuclei (low excited state). 3. Cluster structure of neutron excess beryllium isotopes. 4. Cluster gas like state in C isotope. 5. Dineutron structure of He isotopes. Numbers of strange nuclear structures of light nuclei are illustrated. Antisymmetrized molecular dynamics (AMD) is the recently developed theoretical framework which has been successfully used in heavy ion reactions and nuclear structure studies. Successful application of AMD to the isotopes of Be, B and C are illustrated. (S. Funahashi)

  12. Structure of Light Neutron-rich Nuclei

    International Nuclear Information System (INIS)

    Dlouhy, Zdenek

    2007-01-01

    In this contribution we searched for irregularities in various separation energies in the frame of mass measurement of neutron-rich nuclei at GANIL. On this basis we can summarize that the new doubly magic nuclei are 8 He, 22 O and 24 O. They are characterized by extra stability and, except 24 O, they cannot accept and bind additional neutrons. However, if we add to these nuclei a proton we obtain 9 Li and 25 F which are the core for two-neutron halo nucleus 11 Li and enables that fluorine can bound even 6 more neutrons, respectively. In that aspect the doubly magic nuclei in the neutron-rich region can form the basis either for neutron halo or very neutron-rich nuclei. (Author)

  13. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    Kritchman, E.M.

    1979-01-01

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

  14. Analysis of a Thin Optical Lens Model

    Science.gov (United States)

    Ivchenko, Vladimir V.

    2011-01-01

    In this article a thin optical lens model is considered. It is shown that the limits of its applicability are determined not only by the ratio between the thickness of the lens and the modules of the radii of curvature, but above all its geometric type. We have derived the analytical criteria for the applicability of the model for different types…

  15. Mathematical Lens: How Much Can You Bench?

    Science.gov (United States)

    Bolognese, Chris A.

    2013-01-01

    "How Much Can You Bench?" appears in the "Mathematical Lens" section of "Mathematics Teacher." "Mathematical Lens" uses photographs as a springboard for mathematical inquiry and appears in every issue of "Mathematics Teacher." This month the mathematics behind the photograph includes finding areas…

  16. Plasma Lens for Muon and Neutrino Beams

    International Nuclear Information System (INIS)

    Kahn, S.A.; Korenev, S.; Bishai, M.; Diwan, M.; Gallardo, J.C.; Hershcovitch, A.; Johnson, B.M.

    2008-01-01

    The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-energy lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma for optimum focusing. The plasma lens is immersed in an additional solenoid magnetic field to facilitate the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. Plasma lenses have the additional advantage of negligible pion absorption and scattering by the lens material and reduced neutrino contamination during anti-neutrino running. Results of particle simulations using plasma lens will be presented

  17. Clinical evaluation of direct and photosensitized ultraviolet radiation damage to the lens

    International Nuclear Information System (INIS)

    Hockwin, O.; Lerman, S.

    1982-01-01

    We are reporting a new, objective, and quantitative method for monitoring age-related molecular changes in the human ocular lens in vivo, as expressed by increases in at least two (nontryptophan) fluorescence wavelengths. These fluorescence wavelengths appear to be caused by photochemically induced changes in the lens, and they reflect the ultraviolet (UV) filtering capacity of the patients' ocular lenses. These data correlate with previously reported in vitro lens fluorescence changes that are associated with the aging process. This method will also detect alterations in lenticular fluorescence caused by photosensitized as well as direct UV radiation damage

  18. Opto-mechatronics issues in solid immersion lens based near-field recording

    Science.gov (United States)

    Park, No-Cheol; Yoon, Yong-Joong; Lee, Yong-Hyun; Kim, Joong-Gon; Kim, Wan-Chin; Choi, Hyun; Lim, Seungho; Yang, Tae-Man; Choi, Moon-Ho; Yang, Hyunseok; Rhim, Yoon-Chul; Park, Young-Pil

    2007-06-01

    We analyzed the effects of an external shock on a collision problem in a solid immersion lens (SIL) based near-field recording (NFR) through a shock response analysis and proposed a possible solution to this problem with adopting a protector and safety mode. With this proposed method the collision between SIL and media can be avoided. We showed possible solution for contamination problem in SIL based NFR through a numerical air flow analysis. We also introduced possible solid immersion lens designs to increase the fabrication and assembly tolerances of an optical head with replicated lens. Potentially, these research results could advance NFR technology for commercial product.

  19. Strength of Coriolis Coupling in actinide nuclei

    International Nuclear Information System (INIS)

    Peker, L.K.; Rasmussen, J.O.; Hamilton, J.H.

    1982-01-01

    Coriolis Coupling V/sub cor/ plays an important role in deformed nuclei. V/sub cor/ is proportional to h 2 /J[j (j + 1) -Ω (Ω + 1)]/sup 1/2/ and therefore is particularly significant in the nuclei with large j and low Ω Nilsson levels close to Fermi surface: n(i/sub 13/2/) in A = 150 to 170 rare-earth nuclei and p(i/sub 13/2/) and n(j/sub 15/2/) in A greater than or equal to 224 actinide nuclei. Because of larger j (n(j/sub 15/2/) versus n(i/sub 13/2/)) and smaller deformations (β approx. = 0.22 versus β 0.28) it was reasonable to expect that in actinide nuclei Coriolis effects are stronger than in the rare earth nuclei. Recently it was realized that the strength of observed Coriolis effects depends not only on the genuine Coriolis Coupling but also on the interplay between Coriolis ad pairing forces which leads to an interference between the wave functions of two mixing rotational bands. As a consequence the effective interaction V/sub eff/ of both bands is an oscillating function of the degree of shell filling (or chemical potential lambda F). It was shown that in the rare earth nuclei this interference strongly influenced conclusions about the trends in the Coriolis coupling strength and explained many of the observed band-mixing features (the sharpness of back banding curves, details of the blocking effect etc.). From theoretical analysis it was concluded that in the majority of actinide nuclei the effective interaction V/sub eff/ is strong, and therefore the Coriolis band-mixing have to be very strong. In this paper we would like to demonstrate that contrary to these predictions experimental data suggest that Coriolis band mixing in studied actinide nuclei is relatively weak and possibly significantly weaker than in rare earth nuclei

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

    Directory of Open Access Journals (Sweden)

    Yu Qin

    2015-05-01

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

  1. Isovector coupling channel and central properties of the charge density distribution in heavy spherical nuclei

    International Nuclear Information System (INIS)

    Haddad, S.

    2010-01-01

    The influence of the isovector coupling channel on the central depression parameter and the central value of the charge density distribution in heavy spherical nuclei was studied. The isovector coupling channel leads to about 50% increase of the central depression parameter, and weakens the dependency of both central depression parameter and the central density on the asymmetry, impressively contributing to the semibubble form of the charge density distribution in heavy nuclei, and increasing the probability of larger nuclei with higher proton numbers and higher neutron-to-proton ratios stable. (author)

  2. LensEnt2: Maximum-entropy weak lens reconstruction

    Science.gov (United States)

    Marshall, P. J.; Hobson, M. P.; Gull, S. F.; Bridle, S. L.

    2013-08-01

    LensEnt2 is a maximum entropy reconstructor of weak lensing mass maps. The method takes each galaxy shape as an independent estimator of the reduced shear field and incorporates an intrinsic smoothness, determined by Bayesian methods, into the reconstruction. The uncertainties from both the intrinsic distribution of galaxy shapes and galaxy shape estimation are carried through to the final mass reconstruction, and the mass within arbitrarily shaped apertures are calculated with corresponding uncertainties. The input is a galaxy ellipticity catalog with each measured galaxy shape treated as a noisy tracer of the reduced shear field, which is inferred on a fine pixel grid assuming positivity, and smoothness on scales of w arcsec where w is an input parameter. The ICF width w can be chosen by computing the evidence for it.

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

    International Nuclear Information System (INIS)

    Kumari, S. Sindhu; Varadaraj, Kulandaiappan

    2014-01-01

    scanning electron micrographs of lenses of both mouse models showed increased extracellular space between fiber cells. Water content determination study showed increase in water in the lenses of these mouse models. In summary, lens transparency, CTCA and compact packing of fiber cells were affected due to the loss of 50% AQP0 leading to larger extracellular space, more water content and SA, possibly due to alteration in RING. To our knowledge, this is the first report identifying the role of AQP0 in RING development to ward off lens SA during focusing

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-03

    . Transmission and scanning electron micrographs of lenses of both mouse models showed increased extracellular space between fiber cells. Water content determination study showed increase in water in the lenses of these mouse models. In summary, lens transparency, CTCA and compact packing of fiber cells were affected due to the loss of 50% AQP0 leading to larger extracellular space, more water content and SA, possibly due to alteration in RING. To our knowledge, this is the first report identifying the role of AQP0 in RING development to ward off lens SA during focusing.

  5. Changes of enzyme activities in lens after glaucoma trabecular resection

    Directory of Open Access Journals (Sweden)

    Jian-Ping Wang

    2013-08-01

    Full Text Available AIM: To observe the change of lens antioxidant enzyme activity after glaucoma trabecular resection. METHODS: Thirty-two eyes of sixteen New-Zealand rabbits(2.2-2.4kgwere divided into two groups. The left eyes of rabbits underwent standard glaucoma trabecular resection were treatment group, and the normal right eyes served as controls. Transparency of lenses was monitored by a slit-lamp biomicroscopy before and after glaucoma trabecular resection. The morphology of lens cells was observed under the light microscope.The activities of Na+-K+-ATPase,catalase(CAT, glutathion peroxidase(GSH-px, glutathione reductase(GR, superoxide dismutase(SODand content of malondialdehyde(MDAin lenses were detected six months after trabecular resection. RESULTS: Lenses were clear in both treatment group and normal control group during the six months after operation. The morphology and structure of lens cells were normal under the light microscope in both operation group and normal group. The activity of lens cells antioxidant enzyme activity were significantly decreased in operation group compared with control group, Na+-K+-ATPase declined by 20.97%, CAT declined by 16.36%, SOD declined by 4.46%, GR declined by 4.85%, GSH-px declined by 10.02%, and MDA increased by 16.31%. CONCLUSION: Glaucoma trabecular resection can induce the change of Na+-K+-ATPase, CAT, GSH-px, GR, SOD and MDA in lens of rabbit. Glaucoma filtration surgery for the occurrence of cataract development mechanism has important guiding significance.

  6. Wind lens technology and its application to wind and water turbine and beyond

    Directory of Open Access Journals (Sweden)

    Ohya Yuji

    2017-01-01

    Full Text Available Wind lens is a new type of wind power system consisting of a simple brimmed ring structure that surrounds the rotor causing greater wind to pass through the turbine. As a consequence, the turbine's efficiency of capturing energy from the wind gets dramatically increased. A Wind lens turbine can generate 2–5 times the power of an existing wind turbine given at the same rotor diameter and incoming wind speed. This fluid dynamical effect is also effective in the water. We have developed 1–3 kW Wind lens turbines and a 100 kW Wind lens turbine. In addition to the enhanced output power, Wind lens turbine is quiet. The technology is now used in an offshore experiment with a hexagonal float 18 meters in diameter set off the coast of Hakata Bay in Fukuoka City. Moreover, we are now pursuing larger size Wind lens turbines through multi-rotor design consisting of multiple Wind lens turbines in a same vertical plane to embody larger total power output.

  7. Lens epithelial cell apoptosis is an early event in the development of UVB-induced cataract.

    Science.gov (United States)

    Li, W C; Spector, A

    1996-01-01

    Epidemiological and experimental studies have revealed that exposure to UV can induce cataractogenesis. To investigate the mechanism of this induction, viability of the lens epithelial cells from UVB-treated rat lenses were examined. Irradiation of the cultured rat lenses with 8 J/s/m2 UVB for 60 min triggers lens epithelial cell apoptosis as determined by terminal deoxyribonucleotide transferase (TdT) labeling and DNA fragmentation assays. The apoptotic lens epithelial cells were initially found in the equatorial region and then quickly appeared in both equatorial and central regions. The percentage of apoptotic cells continuously increased during the postirradiation incubation. After a 5-h post-UVB incubation, more than 50% of the lens epithelial cells were apoptotic. By 24 h, all of the lens epithelial cells in the irradiated lenses were dead through apoptosis. Associated with this apoptotic process is a large upregulation of the proto-oncogene, c-fos. Opacification appears to follow the death of lens epithelial cells occurring first in the equatorial region and then in the central area. This is also true of classical cataract parameters such as non-protein thiol and wet weight, which are significantly modified only after appreciable epithelial cell apoptosis. Together, these results suggest that the rapid apoptotic death of the lens epithelial cells induced by UVB initiates cataract development.

  8. A Class I UV-blocking (senofilcon A) soft contact lens prevents UVA-induced yellow fluorescence and NADH loss in the rabbit lens nucleus in vivo.

    Science.gov (United States)

    Giblin, Frank J; Lin, Li-Ren; Simpanya, Mukoma F; Leverenz, Victor R; Fick, Catherine E

    2012-09-01

    It is known that fluorescence, much of it caused by UVA light excitation, increases in the aging human lens, resulting in loss of sharp vision. This study used an in vivo animal model to investigate UVA-excited fluorescence in the rabbit lens, which contains a high level of the UVA chromophore NADH, existing both free and bound to λ-crystallin. Also, the ability of a Class I (senofilcon A) soft contact lens to protect against UVA-induced effects on the rabbit lens was tested. Rabbit eyes were irradiated with UVA light in vivo (100 mW/cm(2) on the cornea) for 1 h using monochromatic 365 nm light. Irradiation was conducted in the presence of either a senofilcon A contact lens, a minimally UV-absorbing lotrafilcon A contact lens, or no contact lens at all. Eyes irradiated without a contact lens showed blue 365 nm-excited fluorescence initially, but this changed to intense yellow fluorescence after 1 h. Isolated, previously irradiated lenses exhibited yellow fluorescence originating from the lens nucleus when viewed under 365 nm light, but showed normal blue fluorescence arising from the cortex. Previously irradiated lenses also exhibited a faint yellow color when observed under visible light. The senofilcon A contact lens protected completely against the UVA-induced effects on fluorescence and lens yellowing, whereas the lotrafilcon A lens showed no protection. The UVA-exposure also produced a 53% loss of total NADH (free plus bound) in the lens nucleus, with only a 13% drop in the anterior cortex. NADH loss in the nucleus was completely prevented with use of a senofilcon A contact lens, but no significant protection was observed with a lotrafilcon A lens. Overall, the senofilcon A lens provided an average of 67% protection against UVA-induced loss of four pyridine nucleotides in four different regions of the lens. HPLC analysis with fluorescence detection indicated a nearly six-fold increase in 365 nm-excited yellow fluorescence arising from lens nuclear

  9. Effects of near-UV radiation on the protein of the grey squirrel lens

    International Nuclear Information System (INIS)

    Zigman, S.; Paxhia, T.; Waldron, W.

    1988-01-01

    In vivo exposure of grey squirrels to 40W BLB illumination resulted in alterations in the state of the lens crystallins, mainly in the outer layer of the lens. HPLC revealed an increase of the void volume or crosslinked crystallins and an increase in peptides with molecular weights lower than 20,000 d. In vitro exposure of squirrel lens aqueous extracts to Woods lamp radiation (predominantly 365 nm) led to similar but more exaggerated changes as viewed by high performance liquid chromatography. When viewed by polyacrylamide gel electrophoresis (PAGE), soluble protein crosslinking was also observed. The near-UV absorbing chromophores of low molecular weight present in the lens served as photosensitizers that enhanced the protein changes. Sodium azide inhibited the changes, indicating a role for singlet oxygen in the crosslinking. (author)

  10. Effects of near-UV radiation on the protein of the grey squirrel lens.

    Science.gov (United States)

    Zigman, S; Paxhia, T; Waldron, W

    1988-06-01

    In vivo exposure of grey squirrels to 40W BLB illumination resulted in alterations in the state of the lens crystallins, mainly in the outer layer of the lens. HPLC revealed an increase of the void volume or crosslinked crystallins and an increase in peptides with molecular weights lower than 20,000 d. In vitro exposure of squirrel lens aqueous extracts to Woods lamp radiation (predominantly 365 nm) led to similar but more exaggerated changes as viewed by high performance liquid chromatography. When viewed by polyacrylamide gel electrophoresis (PAGE), soluble protein crosslinking was also observed. The near-UV absorbing chromophores of low molecular weight present in the lens served as photosensitizers that enhanced the protein changes. Sodium azide inhibited the changes, indicating a role for singlet oxygen in the crosslinking.

  11. Effects of near-UV radiation on the protein of the grey squirrel lens

    Energy Technology Data Exchange (ETDEWEB)

    Zigman, S; Paxhia, T; Waldron, W

    1988-06-01

    In vivo exposure of grey squirrels to 40W BLB illumination resulted in alterations in the state of the lens crystallins, mainly in the outer layer of the lens. HPLC revealed an increase of the void volume or crosslinked crystallins and an increase in peptides with molecular weights lower than 20,000 d. In vitro exposure of squirrel lens aqueous extracts to Woods lamp radiation (predominantly 365 nm) led to similar but more exaggerated changes as viewed by high performance liquid chromatography. When viewed by polyacrylamide gel electrophoresis (PAGE), soluble protein crosslinking was also observed. The near-UV absorbing chromophores of low molecular weight present in the lens served as photosensitizers that enhanced the protein changes. Sodium azide inhibited the changes, indicating a role for singlet oxygen in the crosslinking.

  12. Development of a Fresnel lens for cold neutrons based on neutron refractive optics

    International Nuclear Information System (INIS)

    Oku, T.; Morita, S.; Moriyasu, S.; Yamagata, Y.; Ohmori, H.; Takizawa, Y.; Shimizu, H.M.; Hirota, T.; Kiyanagi, Y.; Ino, T.; Furusaka, M.; Suzuki, J.

    2001-01-01

    We have developed compound refractive lenses (CRLs) for cold neutrons, which are made of vitreous silica and have an effective potential of (90.1-2.7x10 -4 i) neV. In the case of compound refractive optics, neutron absorption by the material deteriorates lens performance. Thus, to prevent an increase in neutron absorption with increasing beam size, we have developed Fresnel lenses using the electrolytic in-process dressing grinding technique. The lens characteristics were carefully investigated with experimental and numerical simulation studies. The lenses functioned as a neutron focusing lens, and the focal length of 14 m was obtained with a 44-element series of the Fresnel lenses for 10 A neutrons. Moreover, good neutron transmission of 0.65 for 15 A neutrons was obtained due to the shape effect. According to comprehensive analysis of the obtained results, it is possible to realize a CRL for practical use by choosing a suitable lens shape and material

  13. A new spin on nuclei

    International Nuclear Information System (INIS)

    Clark, R.; Wadsworth, B.

    1998-01-01

    Magnetic rotation is a new phenomenon that is forcing physicists to rethink their understanding of what goes on inside the nucleus The rotation of quantum objects has a long and distinguished history in physics. In 1912 the Danish scientist Niels Bjerrum was the first to recognize that the rotation of molecules is quantized. In 1938 Edward Teller and John Wheeler observed similar features in the spectra of excited nuclei, and suggested that this was caused by the nucleus rotating. But a more complete explanation had to wait until 1951, when Aage Bohr (the son of Niels) pointed out that rotation was a consequence of the nucleus deforming from its spherical shape. We owe much of our current understanding of nuclear rotation to the work of Bohr and Ben Mottelson, who shared the 1975 Nobel Prize for Physics with James Rainwater for developing a model of the nucleus that combined the individual and collective motions of the neutrons and protons inside the nucleus. What makes it possible for a nucleus to rotate? Quantum mechanically, a perfect sphere cannot rotate because it appears the same when viewed from any direction and there is no point of reference against which its change in position can be detected. To see the rotation the spherical symmetry must be broken to allow an orientation in space to be defined. For example, a diatomic molecule, which has a dumbbell shape, can rotate about the two axes perpendicular to its axis of symmetry. A quantum mechanical treatment of a diatomic molecule leads to a very simple relationship between rotational energy, E, and angular momentum. This energy is found to be proportional to J(J + 1), where J is the angular momentum quantum number. The molecule also has a magnetic moment that is proportional to J. These concepts can be applied to the atomic nucleus. If the distribution of mass and/or charge inside the nucleus becomes non-spherical then the nucleus will be able to rotate. The rotation is termed ''collective'' because many

  14. Symmetry and Phase Transitions in Nuclei

    International Nuclear Information System (INIS)

    Iachello, F.

    2009-01-01

    Phase transitions in nuclei have received considerable attention in recent years, especially after the discovery that, contrary to expectations, systems at the critical point of a phase transition display a simple structure. In this talk, quantum phase transitions (QPT), i.e. phase transitions that occur as a function of a coupling constant that appears in the quantum Hamiltonian, H, describing the system, will be reviewed and experimental evidence for their occurrence in nuclei will be presented. The phase transitions discussed in the talk will be shape phase transitions. Different shapes have different symmetries, classified by the dynamic symmetries of the Interacting Boson Model, U(5), SU(3) and SO(6). Very recently, the concept of Quantum Phase Transitions has been extended to Excited State Quantum Phase Transitions (ESQPT). This extension will be discussed and some evidence for incipient ESQPT in nuclei will be presented. Systems at the critical point of a phase transition are called 'critical systems'. Approximate analytic formulas for energy spectra and other properties of 'critical nuclei', in particular for nuclei at the critical point of the second order U(5)-SO(6) transition, called E(5), and along the line of first order U(5)-SU(3) transitions, called X(5), will be presented. Experimental evidence for 'critical nuclei' will be also shown. Finally, the microscopic derivation of shape phase transitions in nuclei within the framework of density functional methods will be briefly discussed.(author)

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

    Directory of Open Access Journals (Sweden)

    Claire M Elkins

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

  16. Lessons learned: wrong intraocular lens.

    Science.gov (United States)

    Schein, Oliver D; Banta, James T; Chen, Teresa C; Pritzker, Scott; Schachat, Andrew P

    2012-10-01

    To report cases involving the placement of the wrong intraocular lens (IOL) at the time of cataract surgery where human error occurred. Retrospective small case series, convenience sample. Seven surgical cases. Institutional review of errors committed and subsequent improvements to clinical protocols. Lessons learned and changes in procedures adapted. The pathways to a wrong IOL are many but largely reflect some combination of poor surgical team communication, transcription error, lack of preoperative clarity in surgical planning or failure to match the patient, and IOL calculation sheet with 2 unique identifiers. Safety in surgery involving IOLs is enhanced both by strict procedures, such as an IOL-specific "time-out," and the fostering of a surgical team culture in which all members are encouraged to voice questions and concerns. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  17. Radiation studies in Lens culinaris

    International Nuclear Information System (INIS)

    Sinha, S.S.N.

    1977-01-01

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

  18. Measurement of total reaction cross sections of exotic neutron rich nuclei

    International Nuclear Information System (INIS)

    Mittig, W.; Chouvel, J.M.; Wen Long, Z.

    1987-01-01

    Total reaction cross-sections of neutron rich nuclei from C to Mg in a thick Si-target have been measured using the detection of the associated γ-rays in a 4Π-geometry. This cross-section strongly increases with neutron excess, indicating an increase of as much as 15% of the reduced strong absorption radius with respect to stable nuclei

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

    Science.gov (United States)

    Sonier, Marcus; Wronski, Matt; Yeboah, Collins

    2015-03-08

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

  20. In Vitro Effect of Lysozyme on Albumin Deposition to Hydrogel Contact Lens Materials.

    Science.gov (United States)

    Babaei Omali, Negar; Subbaraman, Lakshman N; Heynen, Miriam; Fadli, Zohra; Coles-Brennan, Chantal; Jones, Lyndon W

    2017-11-01

    Albumin deposition on contact lenses could be detrimental to contact lens (CL) wear because this may increase the risk of bacterial binding and reduce comfort. Lysozyme deposition on selected lens materials would reduce albumin deposition on lenses. This study aims to determine if lysozyme deposition on CLs could act as a barrier against subsequent albumin adsorption, using an in vitro model. Six hydrogel CL materials (etafilcon A, polymacon, nelfilcon A, omafilcon A, ocufilcon B, and nesofilcon A) were evaluated. Four CLs of each type were soaked in lysozyme solution for 16 hours at 37°C. Lysozyme-coated lenses were then placed in vials with 1.5 mL of artificial tear solution containing I-labeled albumin for 16 hours at 37°C with shaking. Four uncoated lenses of each type were used as controls. Lenses soaked in radiolabeled albumin were rinsed in a phosphate-buffered saline solution, and radioactive counts were measured directly on lenses using a gamma counter. Albumin uptake on lenses was measured using a calibration curve by plotting radioactive counts versus protein concentration. Results are reported as mean ± SD. Lysozyme-coated etafilcon A lenses exhibited lower levels of deposited albumin than uncoated etafilcon A lenses (58 ± 12 vs. 84 ± 5 ng/lens; P albumin adsorption between control (uncoated) and lysozyme-coated polymacon (105 ± 10 vs. 110 ± 34 ng/lens), nelfilcon A (51 ± 7 vs. 42 ± 20 ng/lens), omafilcon A (90 ± 20 vs. 80 ± 38 ng/lens), ocufilcon B (87 ± 20 vs. 115 ± 50 ng/lens), and nesofilcon A (170 ± 29 vs. 161 ± 10 ng/lens) lens materials (P > .05). Uncoated nesofilcon A lenses deposited the highest amount of albumin when compared with other uncoated lenses (P albumin, which may potentially be beneficial to CL wearers.

  1. Refractive power and biometric properties of the nonhuman primate isolated crystalline lens.

    Science.gov (United States)

    Borja, David; Manns, Fabrice; Ho, Arthur; Ziebarth, Noel M; Acosta, Ana Carolina; Arrieta-Quintera, Esdras; Augusteyn, Robert C; Parel, Jean-Marie

    2010-04-01

    Purpose. To characterize the age dependence of shape, refractive power, and refractive index of isolated lenses from nonhuman primates. Methods. Measurements were performed on ex vivo lenses from cynomolgus monkeys (cyno: n = 120; age, 2.7-14.3 years), rhesus monkeys (n = 61; age, 0.7-13.3 years), and hamadryas baboons (baboon: n = 16; age, 1.7-27.3 years). Lens thickness, diameter, and surface curvatures were measured with an optical comparator. Lens refractive power was measured with a custom optical system based on the Scheiner principle. The refractive contributions of the gradient, the surfaces, and the equivalent refractive index were calculated with optical ray-tracing software. The age dependence of the optical and biometric parameters was assessed. Results. Over the measured age range isolated lens thickness decreased (baboon: -0.04, cyno: -0.05, and rhesus: -0.06 mm/y) and equatorial diameter increased (logarithmically for the baboon and rhesus, and linearly for cyno: 0.07 mm/y). The isolated lens surfaces flattened and the corresponding refractive power from the surfaces decreased with age (-0.33, -0.48, and -0.68 D/y). The isolated lens equivalent refractive index decreased (only significant for the baboon, -0.001 D/y), and as a result the total isolated lens refractive power decreased with age (baboon: -1.26, cyno: -0.97, and rhesus: -1.76 D/y). Conclusions. The age-dependent trends in the optical and biometric properties, growth, and aging, of nonhuman primate lenses are similar to those of the pre-presbyopic human lens. As the lens ages, the decrease in refractive contributions from the gradient refractive index causes a rapid age-dependent decrease in maximally accommodated lens refractive power.

  2. A PDMS-based cylindrical hybrid lens for enhanced fluorescence detection in microfluidic systems.

    Science.gov (United States)

    Lin, Bor-Shyh; Yang, Yu-Ching; Ho, Chong-Yi; Yang, Han-Yu; Wang, Hsiang-Yu

    2014-02-13

    Microfluidic systems based on fluorescence detection have been developed and applied for many biological and chemical applications. Because of the tiny amount of sample in the system; the induced fluorescence can be weak. Therefore, most microfluidic systems deploy multiple optical components or sophisticated equipment to enhance the efficiency of fluorescence detection. However, these strategies encounter common issues of complex manufacturing processes and high costs. In this study; a miniature, cylindrical and hybrid lens made of polydimethylsiloxane (PDMS) to improve the fluorescence detection in microfluidic systems is proposed. The hybrid lens integrates a laser focusing lens and a fluorescence collecting lens to achieve dual functions and simplify optical setup. Moreover, PDMS has advantages of low-cost and straightforward fabrication compared with conventional optical components. The performance of the proposed lens is first examined with two fluorescent dyes and the results show that the lens provides satisfactory enhancement for fluorescence detection of Rhodamine 6G and Nile Red. The overall increments in collected fluorescence signal and detection sensitivity are more than 220% of those without lens, and the detection limits of Rhodamine 6G and Nile red are lowered to 0.01 μg/mL and 0.05 μg/mL, respectively. The hybrid lens is further applied to the detection of Nile red-labeled Chlorella vulgaris cells and it increases both signal intensity and detection sensitivity by more than 520%. The proposed hybrid lens also dramatically reduces the variation in detected signal caused by the deviation in incident angle of excitation light.

  3. Neutron rich nuclei around 132Sn

    International Nuclear Information System (INIS)

    Bhattacharya, Sarmishtha

    2016-01-01

    The neutron rich nuclei with few particles or holes in 132 Sn have various experimental and theoretical interest to understand the evolution of nuclear structure around the doubly magic shell closure Z=50 and N=82. Some of the exotic neutron rich nuclei in this mass region are situated near waiting points in the r-process path and are of special astrophysical interest. Neutron rich nuclei near 132 Sn have been studied using fission fragment spectroscopy. The lifetime of low lying isomeric states have been precisely measured and the beta decay from the ground and isomeric states have been characterized using gamma-ray spectroscopy

  4. Collective models of transition nuclei Pt. 2

    International Nuclear Information System (INIS)

    Dombradi, Zs.

    1982-01-01

    The models describing the even-odd and odd-odd transition nuclei (nuclei of moderate ground state deformation) are reviewed. The nuclear core is described by models of even-even nuclei, and the interaction of a single particle and the core is added. Different models of particle-core coupling (phenomenological models, collective models, nuclear field theory, interacting boson-fermion model, vibration nucleon cluster model) and their results are discussed. New developments like dynamical supersymmetry and new research trends are summarized. (D.Gy.)

  5. Coulomb energy differences in mirror nuclei

    International Nuclear Information System (INIS)

    Lenzi, Silvia M

    2006-01-01

    By comparing the excitation energies of analogue states in mirror nuclei, several nuclear structure properties can be studied as a function of the angular momentum up to high spin states. They can be described in the shell model framework by including electromagnetic and nuclear isospin-non-conserving interactions. Calculations for the mirror energy differences in nuclei of the f 7/2 shell are described and compared with recent experimental data. These studies are extended to mirror nuclei in the upper sd and fp shells

  6. Bound states of Θ+ in nuclei

    International Nuclear Information System (INIS)

    Oset, E.; Cabrera, D.; Li, Q.B.; Magas, V.K.; Vicente Vacas, M.J.

    2005-01-01

    We study the binding energy and the width of the Θ + in nuclei, associated to the KN and KπN components. The first one leads to negligible contributions while the second one leads to a sizeable attraction, enough to bind the Θ + in nuclei. Pauli blocking and binding effects on the KN decay reduce considerably the Θ + decay width in nuclei and medium effects associated to the KπN component also lead to a very small width, as a consequence of which one finds separation between the bound levels considerably larger than the width of the states

  7. Is there chirality in atomic nuclei?

    International Nuclear Information System (INIS)

    Meng Jie

    2009-01-01

    Static chiral symmetries are common in nature, for example, the macroscopic spirals of snail shells, the microscopic handedness of certain molecules, and human hands. The concept of chirality in atomic nuclei was first proposed in 1997, and since then many efforts have been made to understand chiral symmetry and its spontaneous breaking in atomic nuclei. Recent theoretical and experimental progress in the verification of chirality in atomic nuclei will be reviewed, together with a discussion of the problems that await to be solved in the future. (authors)

  8. Bubble nuclei in relativistic mean field theory

    International Nuclear Information System (INIS)

    Shukla, A.; Aberg, S.; Patra, S.K.

    2011-01-01

    Bubble nuclei are characterized by a depletion of their central density, i.e. the formation of the proton or neutron void and subsequently forming proton or neutron bubble nuclei. Possibility of the formation of bubble nuclei has been explored through different nuclear models and in different mass regions. Advancements in experimental nuclear physics has led our experimental access to many new shapes and structures, which were inaccessible hitherto. In the present paper, the possibility of observing nuclear bubble in oxygen isotopes, particularly for 22 O has been studied

  9. Formation and decay of hot nuclei

    International Nuclear Information System (INIS)

    Tamain, B.

    1992-09-01

    The mechanisms involved in hot nuclei formation and decay and their eventual connexion with fundamental properties of nuclear matter are discussed, i.e. its equation of state is considered. After a brief review of the reactions in which hot nuclei can be formed, the variables which are used to describe them, the corresponding theoretical descriptions and their limits when extreme states are reached are discussed. Experimental evidences for hot nuclei formation are presented, with the corresponding decay properties used as signatures. (R.P.) 64 refs.; 25 figs.; 2 tabs

  10. Hot nuclei: high temperatures, high angular momenta

    International Nuclear Information System (INIS)

    Guerreau, D.

    1991-01-01

    A review is made of the present status concerning the production of hot nuclei above 5 MeV temperature, concentrating mainly on the possible experimental evidences for the attainment of a critical temperature, on the existence of dynamical limitations to the energy deposition and on the experimental signatures for the formation of hot spinning nuclei. The data strongly suggest a nuclear disassembly in collisions involving very heavy ions at moderate incident velocities. Furthermore, hot nuclei seem to be quite stable against rotation on a short time scale. (author) 26 refs.; 12 figs

  11. Evolution of planetary nebula nuclei

    International Nuclear Information System (INIS)

    Shaw, R.A.

    1985-01-01

    The evolution of planetary nebula nuclei (PNNs) is examined with the aid of the most recent available stellar evolution calculations and new observations of these objects. Their expected distribution in the log L-log T plane is calculated based upon the stellar evolutionary models of Paczynski, Schoenberner and Iben, the initial mass function derived by Miller and Scalo, and various assumptions concerning mass loss during post-main sequence evolution. The distribution is found to be insensitive both to the assumed range of main-sequence progenitor mass and to reasonable variations in the age and the star forming history of the galactic disk. Rather, the distribution is determined by the strong dependence of the rate of stellar evolution upon core mass, the steepness of the initial mass function, and to a lesser extent the finite lifetime of an observable planetary nebula. The theoretical distributions are rather different than any of those inferred from earlier observations. Possible observational selection effects that may be responsible are examined, as well as the intrinsic uncertainties associated with the theoretical model predictions. An extensive photometric and smaller photographic survey of southern hemisphere planetary nebulae (PNs) is presented

  12. Shape nuclei and nuclear reactions

    International Nuclear Information System (INIS)

    Yushkov, A.V.

    1975-01-01

    Experimental methods for obtaining the nucleus shape parameters are reviewed throughout the period of 1955-1975. Spatial properties of a nucleus, which can be directly or indirectly measured, are determined. They include: parameters of nucleus localization in space; parameters characterizing the nucleus nonsphericity; parameters of the nucleus nonaxiality. Dimensional parameters of a nucleus, namely, radius R and surface ΔR are derived from electron scattering. The deformation sign is indirectly obtained in the experiments. Parameters of the nucleus shape, namely, the sign and magnitude of nuclear deformation are derived from the mean energy proton scattering by a coupled channels method. The only direct way of deriving the nucleus surface deformation signs is the method of the Blaire phase shift. Results on scattering of electrons, protons, and α-particles on light and medium nuclei are reported. Data on the nucleus shape can be also obtained from reactions with heavy ions. A difference between strong absorptions of incident particles of high and average energy by a nucleus is noted. Numerous diagrams illustrate experimental and theoretical results

  13. Clusters in Nuclei. Vol. 2

    International Nuclear Information System (INIS)

    Beck, Christian

    2012-01-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This second volume follows the successful Lect. Notes Phys. 818 (Vol.1), and comprises six extensive lectures covering the following topics: - Microscopic cluster models - Neutron halo and break-up reactions - Break-up reaction models for two- and three-cluster projectiles - Clustering effects within the di-nuclear model - Nuclear alpha-particle condensates - Clusters in nuclei: experimental perspectives By promoting new ideas and developments while retaining a pedagogical style of presentation throughout, these lectures will serve as both a reference and an advanced teaching manual for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  14. Clusters in Nuclei. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Christian (ed.) [Strasbourg Univ. (France). Inst. Pluridiciplinaire Hubert Curien

    2012-07-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This second volume follows the successful Lect. Notes Phys. 818 (Vol.1), and comprises six extensive lectures covering the following topics: - Microscopic cluster models - Neutron halo and break-up reactions - Break-up reaction models for two- and three-cluster projectiles - Clustering effects within the di-nuclear model - Nuclear alpha-particle condensates - Clusters in nuclei: experimental perspectives By promoting new ideas and developments while retaining a pedagogical style of presentation throughout, these lectures will serve as both a reference and an advanced teaching manual for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  15. Precision lens assembly with alignment turning system

    Science.gov (United States)

    Ho, Cheng-Fang; Huang, Chien-Yao; Lin, Yi-Hao; Kuo, Hui-Jean; Kuo, Ching-Hsiang; Hsu, Wei-Yao; Chen, Fong-Zhi

    2017-10-01

    The poker chip assembly with high precision lens barrels is widely applied to ultra-high performance optical system. ITRC applies the poker chip assembly technology to the high numerical aperture objective lenses and lithography projection lenses because of its high efficiency assembly process. In order to achieve high precision lens cell for poker chip assembly, an alignment turning system (ATS) is developed. The ATS includes measurement, alignment and turning modules. The measurement module is equipped with a non-contact displacement sensor (NCDS) and an autocollimator (ACM). The NCDS and ACM are used to measure centration errors of the top and the bottom surface of a lens respectively; then the amount of adjustment of displacement and tilt with respect to the rotational axis of the turning machine for the alignment module can be determined. After measurement, alignment and turning processes on the ATS, the centration error of a lens cell with 200 mm in diameter can be controlled within 10 arcsec. Furthermore, a poker chip assembly lens cell with three sub-cells is demonstrated, each sub-cells are measured and accomplished with alignment and turning processes. The lens assembly test for five times by each three technicians; the average transmission centration error of assembly lens is 12.45 arcsec. The results show that ATS can achieve high assembly efficiency for precision optical systems.

  16. Bioinspired adaptive gradient refractive index distribution lens

    Science.gov (United States)

    Yin, Kezhen; Lai, Chuan-Yar; Wang, Jia; Ji, Shanzuo; Aldridge, James; Feng, Jingxing; Olah, Andrew; Baer, Eric; Ponting, Michael

    2018-02-01

    Inspired by the soft, deformable human eye lens, a synthetic polymer gradient refractive index distribution (GRIN) lens with an adaptive geometry and focal power has been demonstrated via multilayer coextrusion and thermoforming of nanolayered elastomeric polymer films. A set of 30 polymer nanolayered films comprised of two thermoplastic polyurethanes having a refractive index difference of 0.05 were coextruded via forced-assembly technique. The set of 30 nanolayered polymer films exhibited transmission near 90% with each film varying in refractive index by 0.0017. An adaptive GRIN lens was fabricated from a laminated stack of the variable refractive index films with a 0.05 spherical GRIN. This lens was subsequently deformed by mechanical ring compression of the lens. Variation in the optical properties of the deformable GRIN lens was determined, including 20% variation in focal length and reduced spherical aberration. These properties were measured and compared to simulated results by placido-cone topography and ANSYS methods. The demonstration of a solid-state, dynamic focal length, GRIN lens with improved aberration correction was discussed relative to the potential future use in implantable devices.

  17. Growth studies on Lens culinaris after gamma irradiation

    International Nuclear Information System (INIS)

    Ahmad, S.; Bokhari, F.S.; Shahnaz, F.

    1996-01-01

    A study on growth parameters was carried out on two varieties of Lens culinaris after gamma irradiation. Experiment was conducted at Botanical Garden, Bahauddin Zakariya University, Multan in 1993. The germination percentage, survival percentage, height, branch number, pods per plant and 100-seed weight decreased with the increasing dose of radiation. Comparing the two varieties, variety-86642 appeared more sensitive to radiation than variety-87528

  18. Environmental properties related to active galactic nuclei

    Science.gov (United States)

    Manzer, Lianne H.

    There continues to be significant controversy regarding the mechanisms responsible for the initiation of activity in galactic nuclei. It is well understood that the non-thermal energy produced by an AGN is due to accretion onto a supermassive black hole. It has not yet been determined, however, what leads particular galaxies to become active. An accurate exploration into what triggers an AGN demands an analysis of a large sample of galaxies across a diverse set of environments. In this work, we investigate possible environmental influences by carrying out a statistical investigation of galaxy groups. Using the catalogue of Yang et al. (2007), in which groups of galaxies containing between 2 and 20 members with redshifts between 0.01 -- 0.20 were taken from the Sloan Digital Sky Survey, we investigate the fraction of active galactic nuclei (AGN) within these groups and compare it to the sample of isolated galaxies also obtained from Yang et al. (2007). After correcting our spectroscopic data for extinction and underlying stellar absorption, we classify the galaxy sample using relevant emission-line ratios. We propose an alternate method for classifying emission-line galaxies, including AGN, which builds upon standard diagnostic utilities used for optical classification and includes uncertainties. Such classification probabilities offer a more robust and consistent method of investigating the effect of group environments with galaxy type. We find our sample to be a fair representation of the local universe by comparing the luminosity function of our entire data set to that of Blanton et al. (2001), Blanton et al. (2003b), and Montero-Dorta & Prada (2009). The evidence also suggests that the luminosity function of galaxies differs between isolated galaxies and galaxies in groups. We find a significant increase in the fraction of AGNs identified in grouped environments. On the other hand, we find a higher fraction of starforming galaxies within isolated systems. We

  19. Design of a hyperbolic microwave metallic lens

    International Nuclear Information System (INIS)

    Uckan, T.

    1979-12-01

    Due to problems caused by multiple reflections in the cavity walls of the EBT fusion research device, the use of a horn becomes important for the directivity of waves in the millimetric range. An ordinary dielectric lens cannot be used because of plasma-wall interactions. Microwave metallic lenses, designed to focus the energy into a plane wave, can improve the directivity considerably. By implementing a 70-GHz standard-gain horn with a delay-type hyperbolic lens, which consists of a solid metallic disk with a number of equal size small holes has indicated a gain of 15 dB over the no lens case

  20. Accelerating convergence in automatic lens design

    International Nuclear Information System (INIS)

    Brixner, B.

    1981-01-01

    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

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

    Science.gov (United States)

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

    2017-01-01

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

  2. Experimental Analysis of Desalination Unit Coupled with Solar Water Lens Concentrator

    Science.gov (United States)

    Chaithanya, K. K.; Rajesh, V. R.; Suresh, Rahul

    2016-09-01

    The main problem that the world faces in this scenario is shortage of potable water. Hence this research work rivets to increase the yield of desalination system in an economical way. The integration of solar concentrator and desalination unit can project the desired yield, but the commercially available concentrated solar power technologies (CSP) are not economically viable. So this study proposes a novel method to concentrate ample amount of solar radiation in a cost effective way. Water acting as lens is a highlighted technology initiated in this work, which can be a substitute for CSP systems. And water lens can accelerate the desalination process so as to increase the yield economically. The solar irradiance passing through the water will be concentrated at a focal point, and the concentration depends on curvature of water lens. The experimental analysis of water lens makes use of transparent thin sheet, supported on a metallic structure. The Plano convex shape of water lens is developed by varying the volume of water that is being poured on the transparent thin sheet. From the experimental analysis it is inferred that, as the curvature of water lens increases, solar irradiance can be focused more accurately on to the focus and a higher water temperature is obtained inside the solar still.

  3. Immunoglobulin Concentration in Tears of Contact Lens Wearers

    Science.gov (United States)

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

    2014-01-01

    Purpose: To evaluate changes in the concentration of tear immunoglobulins in contact lens wearers. Methods: A total of 45 cases including 23 contact lens wearers (43 eyes) and 22 age and sex matched healthy controls having no ocular pathology were studied for immunoglobulins (IgA, IgG, IgM) in their tears by single radial immunodiffusion method. Results: Most of the cases used soft (56.6%) and semi-soft gas permeable (30.4%) contact lenses. Tear IgM was detected in only 17.4% and tear IgG in 43.6% of contact lens wearers, while in controls IgG was detected in 9.1% but none of the controls had IgM. There was a significant rise in total tear IgA (13.17 ± 4.44 mg/dl) in contact lens wearer as compared to controls (8.93 ± 3.79 mg/dl). Rise of tear IgA was more in symptomatic patients (15.38 ± 5.28 mg/dl) and in those wearing hard (19.73 ± 5.43 mg/dl) and semi-soft contact lenses (13.31 ± 5.43 mg/dl). A significant increase in tear IgA was noticed in subjects wearing lenses for >3 years (15.69 ± 5.39 mg/dl). About 43.4% of lens wearers were symptomatic and 80% of their lenses showed deposits and/or haziness. All cases with IgM in tear were symptomatic. Conclusion: The relation of immunoglobulin concentration with increasing duration of wear and material of contact lens shows that tear immunoglobulin rise accrues due to mechanical stimulation, hence contact lenses should not be used for a long period and lenses of hard nature should be discouraged. The maintenance, cleaning and deproteinization of the lenses are of high importance to avoid immunostimulation. PMID:25667732

  4. Radiocarbon Dating of the Human Eye Lens Crystallines Reveal Proteins without Carbon Turnover throughout Life

    Science.gov (United States)

    Lynnerup, Niels; Kjeldsen, Henrik; Heegaard, Steffen; Jacobsen, Christina; Heinemeier, Jan

    2008-01-01

    Background Lens crystallines are special proteins in the eye lens. Because the epithelial basement membrane (lens capsule) completely encloses the lens, desquamation of aging cells is impossible, and due to the complete absence of blood vessels or transport of metabolites in this area, there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its 14C content from the atmospheric carbon dioxide. The 14C content of the lens proteins thus reflects the atmospheric content of 14C when the lens crystallines were formed. Precise radiocarbon dating is made possible by comparing the 14C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric 14C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even on a yearly basis this allows very accurate dating. Methodology/Principal Findings Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close relationship may be further expressed as a mathematical model, which takes into account the timing of the crystalline formation. Conclusions/Significance Such a life-long permanence of human tissue has hitherto only been described for dental enamel. In confront to dental enamel it must be held in mind that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the 14C content of various tissues may be used to assess turnover rates and degree of substitution (for example for brain cell DNA). Potential targets may be nervous tissues in terms of senile or pre-senile degradation, as well as other highly

  5. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life.

    Directory of Open Access Journals (Sweden)

    Niels Lynnerup

    Full Text Available BACKGROUND: Lens crystallines are special proteins in the eye lens. Because the epithelial basement membrane (lens capsule completely encloses the lens, desquamation of aging cells is impossible, and due to the complete absence of blood vessels or transport of metabolites in this area, there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its (14C content from the atmospheric carbon dioxide. The (14C content of the lens proteins thus reflects the atmospheric content of (14C when the lens crystallines were formed. Precise radiocarbon dating is made possible by comparing the (14C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric (14C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close relationship may be further expressed as a mathematical model, which takes into account the timing of the crystalline formation. CONCLUSIONS/SIGNIFICANCE: Such a life-long permanence of human tissue has hitherto only been described for dental enamel. In confront to dental enamel it must be held in mind that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14C content of various tissues may be used to assess turnover rates and degree of substitution (for example for brain cell DNA. Potential targets may be nervous tissues in terms of senile or pre

  6. The Giant Dipole Resonance in hot nuclei. Experimental aspects

    International Nuclear Information System (INIS)

    Alamanos, N.; Auger, F.

    1994-12-01

    Some of the most recent experimental results on the GDR in hot nuclei are presented. All data on the γ-decay of the GDR show a saturation of the apparent width and a saturation of the yield. However, it is not clear until now, if these effects are related to a GDR width which either saturates or increases continuously with the excitation energy. Very new data associated to selected exit channels could help to clarify the situation. (author). 14 refs., 7 figs

  7. Nuclear squid: Diabolic pair transfer in rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nikam, R S; Ring, P; Canto, L F

    1987-02-19

    A new unexpected behavior of pair transfer matrix elements in superfluid rotating nuclei is predicted. With increasing angular velocity they drop to zero, change their sign and in some cases even oscillate between positive and negative values. This effect is related to diabolical points in rotating quasiparticle spectra and is closely analogous to the DC-Josephson effect in superconductors in the presence of a magnetic field.

  8. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in the...

  9. 21 CFR 886.5844 - Prescription spectacle lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prescription spectacle lens. 886.5844 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5844 Prescription spectacle lens. (a) Identification. A prescription spectacle lens is a glass or plastic device that is a lens intended to be worn by...

  10. 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 has...

  11. Understanding nuclei in the upper sd - shell

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, M. Saha; Bisoi, Abhijit; Ray, Sudatta [Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India); Kshetri, Ritesh [Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata 700064, India and Sidho-Kanho-Birsha University, Purulia - 723101 (India); Sarkar, S. [Indian Institute of Engineering Science and Technology, Shibpur, Howrah - 711103 (India)

    2014-08-14

    Nuclei in the upper-sd shell usually exhibit characteristics of spherical single particle excitations. In the recent years, employment of sophisticated techniques of gamma spectroscopy has led to observation of high spin states of several nuclei near A ≃ 40. In a few of them multiparticle, multihole rotational states coexist with states of single particle nature. We have studied a few nuclei in this mass region experimentally, using various campaigns of the Indian National Gamma Array setup. We have compared and combined our empirical observations with the large-scale shell model results to interpret the structure of these nuclei. Indication of population of states of large deformation has been found in our data. This gives us an opportunity to investigate the interplay of single particle and collective degrees of freedom in this mass region.

  12. Perspectives of production of superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Adamian, G. G.; Antonenko, N. V., E-mail: antonenk@theor.jinr.ru; Bezbakh, A. N.; Sargsyan, V. V. [Joint Institute for Nuclear Research, RU–141980 Dubna (Russian Federation); Scheid, W. [Institut für Theoretische Physik der Justus-Liebig-Universität, D–35392 Giessen (Germany)

    2016-07-07

    Possible ways of production of superheavies are discussed. Impact of nuclear structure on the production of superheavy nuclei in complete fusion reactions is discussed. The proton shell closure at Z = 120 is discussed.

  13. Nuclear Computational Low Energy Initiative (NUCLEI)

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Sanjay K. [University of Washington

    2017-08-14

    This is the final report for University of Washington for the NUCLEI SciDAC-3. The NUCLEI -project, as defined by the scope of work, will develop, implement and run codes for large-scale computations of many topics in low-energy nuclear physics. Physics to be studied include the properties of nuclei and nuclear decays, nuclear structure and reactions, and the properties of nuclear matter. The computational techniques to be used include Quantum Monte Carlo, Configuration Interaction, Coupled Cluster, and Density Functional methods. The research program will emphasize areas of high interest to current and possible future DOE nuclear physics facilities, including ATLAS and FRIB (nuclear structure and reactions, and nuclear astrophysics), TJNAF (neutron distributions in nuclei, few body systems, and electroweak processes), NIF (thermonuclear reactions), MAJORANA and FNPB (neutrino-less double-beta decay and physics beyond the Standard Model), and LANSCE (fission studies).

  14. Infrared Observations of Cometary Dust and Nuclei

    Science.gov (United States)

    Lisse, Carey

    2004-01-01

    This bibliography lists citations for publications published under the grant. Subjects of the publications include cometary dust, instellar and interplanetary dust, comet nuclei and comae, Comet Hale-Bopp, infrared observations of comets, mass loss, and comet break-up.

  15. Superheavy nuclei: a relativistic mean field outlook

    International Nuclear Information System (INIS)

    Afanasjev, A.V.

    2006-01-01

    The analysis of quasi-particle spectra in the heaviest A∼250 nuclei with spectroscopic data provides an additional constraint for the choice of effective interaction for the description of superheavy nuclei. It strongly suggests that only the parametrizations which predict Z = 120 and N = 172 as shell closures are reliable for superheavy nuclei within the relativistic mean field theory. The influence of the central depression in the density distribution of spherical superheavy nuclei on the shell structure is studied. A large central depression produces large shell gaps at Z = 120 and N = 172. The shell gaps at Z = 126 and N = 184 are favoured by a flat density distribution in the central part of the nucleus. It is shown that approximate particle number projection (PNP) by means of the Lipkin-Nogami (LN) method removes pairing collapse seen at these gaps in the calculations without PNP

  16. Searching for dual active galactic nuclei

    Indian Academy of Sciences (India)

    K. Rubinur

    2018-02-09

    Feb 9, 2018 ... Abstract. Binary or dual active galactic nuclei (DAGN) are expected from galaxy formation theories. How- ... cuss results from the multi-frequency Expanded Very .... mid-IR color using WISE observations where they have.

  17. Lipkin-Nogami method for rotating nuclei

    International Nuclear Information System (INIS)

    Magierski, P.

    1993-01-01

    The extension of Lipkin-Nogami method to the case of rotating nuclei, where the short-range attraction acting between the nucleus (pairing free) plays a significant role for the coupling scheme is discussed. 7 refs, 6 figs

  18. Collisions on relativistic nuclei: shock waves

    International Nuclear Information System (INIS)

    Gudima, K.K.; Toneev, V.D.

    1976-01-01

    Experiments are analysed which indicate the possible generation of shock waves in collisions of two nuclei. Another interpretation of these data is proposed and the concerned new experiments are discussed

  19. Non-equilibrium entropy in excited nuclei

    International Nuclear Information System (INIS)

    Betak, E.

    1991-06-01

    The time-dependent behaviour of entropy in excited nuclei is investigated. In distinction to recent claims, it is shown that no self-organization is involved in pre-equilibrium nuclear reactions. (author). 9 refs.; 4 figs

  20. ULTRA-RELATIVISTIC NUCLEI: A NEW FRONTIER

    International Nuclear Information System (INIS)

    MCLERRAN, L.

    1999-01-01

    The collisions of ultra-relativistic nuclei provide a window on the behavior of strong interactions at asymptotically high energies. They also will allow the authors to study the bulk properties of hadronic matter at very high densities

  1. Changes in lens following 60Co irradiation

    International Nuclear Information System (INIS)

    Rozsival, P.; Obenberger, J.; Sladkova, J.

    1985-01-01

    Chinchilla rabbit lenses were irradiated using a 60 Co gamma source, and the changes in the transport activities, native weight, water content and dry weight were observed. The heads of rabbits were irradiated with doses of 10 and 20 Gy and functional changes occurring in the lenses were studied till the twenty-fourth week after the irradiation. The weight of the rabbit lens irradiated with a dose of 20 Gy significantly increased after the twelfth week and was maximal 16 weeks after irradiation when also cataracts were observed. The increased weight of lenses was caused by accumulation of water. The decrease in the dry weight of lenses preceded the period of visible cataracts. A decreased uptake of rubidium occurring during in vitro cultivation of lenses was the most sensitive marker for the changes caused by 20 Gy irradiation. It was significantly decreased as early as 8 weeks after irradiation, preceding the increased hydration of lenses by 4 weeks and the presence of visible cataracts by as much as 8 weeks

  2. Multiplexing Visual Signals in the Suprachiasmatic Nuclei.

    Science.gov (United States)

    Stinchcombe, Adam R; Mouland, Joshua W; Wong, Kwoon Y; Lucas, Robert J; Forger, Daniel B

    2017-11-07

    The suprachiasmatic nuclei (SCN), the site of the mammalian circadian (daily) pacemaker, contains thousands of interconnected neurons, some of which receive direct retinal input. Here, we study the fast (<1 s) responses of SCN neurons to visual stimuli with a large-scale mathematical model tracking the ionic currents and voltage of all SCN neurons. We reconstruct the SCN network connectivity and reject 99.99% of theoretically possible SCN networks by requiring that the model reproduces experimentally determined receptive fields of SCN neurons. The model shows how the SCN neuronal network can enhance circadian entrainment by sensitizing a population of neurons in the ventral SCN to irradiance. This SCN network also increases the spatial acuity of neurons and increases the accuracy of a simulated subconscious spatial visual task. We hypothesize that much of the fast electrical activity within the SCN is related to the processing of spatial information. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    Dayang, Wu; Dongbo, Pang

    2017-10-01

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

  4. High energy particle interactions with nuclei

    International Nuclear Information System (INIS)

    Czyz, W.

    1978-01-01

    The recent interest in multiparticle production processes on nuclei was triggered by re-discovering their 'enigmatic simplicity' which has been known to cosmic ray physicists for over 20 years: the mean multiplicity and angular distributions of relativistic secondaries produced on nuclei do not differ markedly from what emerges from p-p collisions. The author considers how such reactions may provide a way of obtaining details of hadron structure. (Auth.)

  5. Hot nuclei, limiting temperatures and excitation energies

    International Nuclear Information System (INIS)

    Peter, J.

    1986-09-01

    Hot fusion nuclei are produced in heavy ion collisions at intermediate energies (20-100 MeV/U). Information on the maximum excitation energy per nucleon -and temperatures- indicated by the experimental data is compared to the predictions of static and dynamical calculations. Temperatures around 5-6 MeV are reached and seem to be the limit of formation of thermally equilibrated fusion nuclei

  6. Electron scattering and collective excitations in nuclei

    International Nuclear Information System (INIS)

    Goutte, D.

    1989-01-01

    Nuclear collective degrees of freedom are investigated through the study of the radial dependance of their wave function. Inelastic electron scattering is shown to be the appropriate tool to extract such a detailed information. Some recent results on spherical as well as deformed nuclei are discussed and the most recent extensions to the mean field approach are compared to these data in order to clarify the present status of our understanding of the dynamical properties of complex nuclei

  7. Proton radioactivity from proton-rich nuclei

    International Nuclear Information System (INIS)

    Guzman, F.; Goncalves, M.; Tavares, O.A.P.; Duarte, S.B.; Garcia, F.; Rodriguez, O.

    1999-03-01

    Half-lives for proton emission from proton-rich nuclei have been calculated by using the effective liquid drop model of heavy-particle decay of nuclei. It is shown that this model is able to offer results or spontaneous proton-emission half-life-values in excellent agreement with the existing experimental data. Predictions of half-life-values for other possible proton-emission cases are present for null orbital angular momentum. (author)

  8. Determining properties of baryon resonances in nuclei

    International Nuclear Information System (INIS)

    Johnson, M.B.; Chen, C.M.; Ernst, D.J.; Jiang, M.F.

    1996-01-01

    Meson-nucleus and photon-nucleus interactions are important sources of information about the medium modifications of baryon resonances in nuclei. Indications of how large the medium effects are for resonances above the Δ 33 (1232) are provided by it combined analysis of photonuclear and pion cross sections in the GeV range of energies. Tile existing data indicate a possible 10-20% renormalization of the pion coupling to higher-lying resonances in nuclei

  9. Nuclei far off the stability line

    International Nuclear Information System (INIS)

    Fenyes, T.

    1978-01-01

    Theoretical and experimental aspects of the formation of some ''exotic'' nuclei far off the stability line were reviewed in addition to the relevant results of research in this field. Results in beta- and gamma-ray spectroscopy, heavy-ion-spectroscopy, achievements in the fields of measuring the atomic mass, the moment, and the radius of the nuclei as well as some astronomical aspects were described. (Z.P.)

  10. Thomas Fermi model of finite nuclei

    International Nuclear Information System (INIS)

    Boguta, J.; Rafelski, J.

    1977-01-01

    A relativistic Thomas-Fermi model of finite-nuclei is considered. The effective nuclear interaction is mediated by exchanges of isoscalar scalar and vector mesons. The authors include also a self-interaction of the scalar meson field and the Coulomb repulsion of the protons. The parameters of the model are constrained by the average nuclear properties. The Thomas-Fermi equations are solved numerically for finite, stable nuclei. The particular case of 208 82 Pb is considered in more detail. (Auth.)

  11. Chemical and physical properties of the normal and aging lens: spectroscopic (UV, fluorescence, phosphorescence, and NMR) analyses

    International Nuclear Information System (INIS)

    Lerman, S.

    1987-01-01

    In vitro [UV absorption, fluorescence, phosphorescence, and nuclear magnetic resonance (NMR)] spectroscopic studies on the normal human lens demonstrate age-related changes which can be correlated with biochemical and photobiologic mechanisms occurring during our lifetime. Chronic cumulative UV exposure results in an age-related increase of photochemically induced chromophores and in color of the lens nucleus. This enables the lens to filter the incident UV radiation, thereby protecting the underlying aging retina from UV photodamage. We have measured the age-related increase in lens fluorescence in vivo on more than 300 normal subjects (1st to 9th decade) by UV slitlamp densitography. These data show a good correlation with the in vitro lens fluorescence studies reported previously and demonstrate that molecular photodamage can be monitored in the lens. In vitro NMR (human and animal lenses) and in vivo experiments currently in progress are rapidly elucidating the physicochemical basis for transparency and the development of light scattering areas. Surface scanning NMR can monitor organophosphate metabolism in the ocular lens in vivo as well as in vitro. These studies demonstrate the feasibility of using biophysical methods (optical spectroscopy and NMR analyses) to delineate age-related parameters in the lens, in vivo as well as in vitro. 46 references

  12. Structure of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Nazarewicz, W.

    2000-01-01

    Complete text of publication follows. The uncharted regions of the (N,Z) plane contain information that can answer many questions of fundamental importance for science: How many protons and neutrons can be clustered together by the strong interaction to form a bound nucleus? What are the proton and neutron magic numbers of the exotic nuclei? What are the properties of very short-lived exotic nuclei with extreme neutron-to-proton ratios? What is the effective nucleon-nucleon interaction in a nucleus that has a very large neutron excess? Nuclear life far from stability is different from that around the stability line; the promised access to completely new combinations of proton and neutron numbers offers prospects for new structural phenomena. The main objective of this talk is to discuss some of the challenges and opportunities of research with exotic nuclei. The covered topics will include: Theoretical challenges; Skins and halos in heavy nuclei; Shape coexistence in exotic nuclei; Beta-decays of neutron-rich nuclei. (author)

  13. Major new sources of biological ice nuclei

    Science.gov (United States)

    Moffett, B. F.; Hill, T.; Henderson-Begg, S. K.

    2009-12-01

    Almost all research on biological ice nucleation has focussed on a limited number of bacteria. Here we characterise several major new sources of biogenic ice nuclei. These include mosses, hornworts, liverworts and cyanobacteria. Ice nucleation in the eukaryotic bryophytes appears to be ubiquitous. The temperature at which these organisms nucleate is that at which the difference in vapour pressure over ice and water is at or close to its maximum. At these temperatures (-8 to -18 degrees C) ice will grow at the expense of supercooled water. These organisms are dependent for their water on occult precipitation - fog, dew and cloudwater which by its nature is not collected in conventional rain gauges. Therefore we suggest that these organism produce ice nuclei as a water harvesting mechanism. Since the same mechanism would also drive the Bergeron-Findeisen process, and as moss is known to become airborne, these nuclei may have a role in the initiation of precipitation. The properties of these ice nuclei are very different from the well characterised bacterial nuclei. We will also present DNA sequence data showing that, although related, the proteins responsible are only very distantly related to the classical bacterial ice nuclei.

  14. AutoLens: Automated Modeling of a Strong Lens's Light, Mass and Source

    Science.gov (United States)

    Nightingale, J. W.; Dye, S.; Massey, Richard J.

    2018-05-01

    This work presents AutoLens, the first entirely automated modeling suite for the analysis of galaxy-scale strong gravitational lenses. AutoLens simultaneously models the lens galaxy's light and mass whilst reconstructing the extended source galaxy on an adaptive pixel-grid. The method's approach to source-plane discretization is amorphous, adapting its clustering and regularization to the intrinsic properties of the lensed source. The lens's light is fitted using a superposition of Sersic functions, allowing AutoLens to cleanly deblend its light from the source. Single component mass models representing the lens's total mass density profile are demonstrated, which in conjunction with light modeling can detect central images using a centrally cored profile. Decomposed mass modeling is also shown, which can fully decouple a lens's light and dark matter and determine whether the two component are geometrically aligned. The complexity of the light and mass models are automatically chosen via Bayesian model comparison. These steps form AutoLens's automated analysis pipeline, such that all results in this work are generated without any user-intervention. This is rigorously tested on a large suite of simulated images, assessing its performance on a broad range of lens profiles, source morphologies and lensing geometries. The method's performance is excellent, with accurate light, mass and source profiles inferred for data sets representative of both existing Hubble imaging and future Euclid wide-field observations.

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

    Science.gov (United States)

    Siedlecki, Damian; Nowak, Jerzy; Zajac, Marek

    2006-01-01

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

  16. Disinfection capacity of PuriLens contact lens cleaning unit against Acanthamoeba.

    Science.gov (United States)

    Hwang, Thomas S; Hyon, Joon Young; Song, Jae Kyung; Reviglio, Victor E; Spahr, Harry T; O'Brien, Terrence P

    2004-01-01

    The PuriLens contact lens system is indicated for cleaning and disinfection of soft (hydrophilic) contact lenses by means of subsonic agitation to remove lens deposits and microorganisms, and ultraviolet irradiation of the storage solution for disinfection. The capacity of the PuriLens system to disinfect storage solutions contaminated with known concentrations of Staphylococcus aureus, Pseudomonas aeruginosa, and Acanthamoeba species was evaluated. An in vitro assessment of the antibacterial and antiparasitic efficacy of the PuriLens system was performed. Separated batches of the storage solution for the cleansing system were contaminated with stock strains of S. aureus and P. aeruginosa. A comparison of the microbiologic content was made between the solution before and after the cycle. The PuriLens system effectively eradicated S. aureus and P. aeruginosa organisms after a 15-minute cycle. However, viable cysts of acanthamoeba were recovered in the solution after the 15-minute cycle. The PuriLens system is highly efficient in protecting against contamination with common bacterial ocular pathogens. Acanthamoeba cysts, however, can survive in the solution or contact lens bath undergoing integrated subsonic debridement and indirect ultraviolet light disinfection. Use of chemical disinfecting solutions that contain agents such as chlorhexidine or other cationic antiseptics may be advisable in conjunction with use of the PuriLens device, especially in high-risk settings.

  17. Contact Lens Visual Rehabilitation in Keratoconus and Corneal Keratoplasty

    Directory of Open Access Journals (Sweden)

    Yelda Ozkurt

    2012-01-01

    Full Text Available Keratoconus is the most common corneal distrophy. It’s a noninflammatory progressive thinning process that leads to conical ectasia of the cornea, causing high myopia and astigmatism. Many treatment choices include spectacle correction and contact lens wear, collagen cross linking, intracorneal ring segments implantation and finally keratoplasty. Contact lenses are commonly used to reduce astigmatism and increase vision. There are various types of lenses are available. We reviewed soft contact lenses, rigid gas permeable contact lenses, piggyback contact lenses, hybrid contact lenses and scleral-semiscleral contact lenses in keratoconus management. The surgical option is keratoplasty, but even after sutur removal, high astigmatism may stil exists. Therefore, contact lens is an adequate treatment option to correct astigmatism after keratoplasty.

  18. D-aspartic acid in aged mouse skin and lens

    International Nuclear Information System (INIS)

    Fujii, Noriko; Muraoka, Shiro; Harada, Kaoru; Tamanoi, Itsuro; Joshima, Hisamasa; Kashima, Masatoshi.

    1987-01-01

    D-aspartic acid (D-Asp) was detected in the skin and lens from naturally aged mice. An analysis of the amino acid composition indicated that D-Asp did not derive from collagen. An immunological analysis using Oucterlony's agar diffusion method also confirmed that the protein containing D-Asp was not a serum protein. The process producing D-Asp is regarded as one other than racemization because the life span of mice is not long enough to permit D-Asp by racemization. Continuous low-dose-rate gamma-irradiation (37R per day) for 102 to 112 days did not increase significantly the amount of D-Asp in skin and lens of mice. (author)

  19. Night Vision Goggles Objectives Lens Focusing Methodology

    National Research Council Canada - National Science Library

    Pinkus, Alan; Task, H. L

    2000-01-01

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

  20. Characteristics of soft X-ray lens

    International Nuclear Information System (INIS)

    Qin Yi

    2007-12-01

    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 10 5 W/cm 2 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/cm 2 can be obtained as far as Qiang-Guang I facility is considered. (authors)